diff options
265 files changed, 7439 insertions, 3689 deletions
diff --git a/Documentation/dev-tools/kcov.rst b/Documentation/dev-tools/kcov.rst index d2c4c27e1702..d83c9ab49427 100644 --- a/Documentation/dev-tools/kcov.rst +++ b/Documentation/dev-tools/kcov.rst @@ -50,6 +50,7 @@ program using kcov: #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> + #include <linux/types.h> #define KCOV_INIT_TRACE _IOR('c', 1, unsigned long) #define KCOV_ENABLE _IO('c', 100) @@ -177,6 +178,8 @@ Comparison operands collection is similar to coverage collection: /* Read number of comparisons collected. */ n = __atomic_load_n(&cover[0], __ATOMIC_RELAXED); for (i = 0; i < n; i++) { + uint64_t ip; + type = cover[i * KCOV_WORDS_PER_CMP + 1]; /* arg1 and arg2 - operands of the comparison. */ arg1 = cover[i * KCOV_WORDS_PER_CMP + 2]; @@ -251,6 +254,8 @@ selectively from different subsystems. .. code-block:: c + /* Same includes and defines as above. */ + struct kcov_remote_arg { __u32 trace_mode; __u32 area_size; diff --git a/arch/alpha/include/asm/spinlock_types.h b/arch/alpha/include/asm/spinlock_types.h index 1d5716bc060b..2526fd3be5fd 100644 --- a/arch/alpha/include/asm/spinlock_types.h +++ b/arch/alpha/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef _ALPHA_SPINLOCK_TYPES_H #define _ALPHA_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 110b305af27f..94d1404923f4 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -32,6 +32,7 @@ config ARM select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_HUGETLBFS if ARM_LPAE + select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF select ARCH_USE_MEMTEST @@ -69,7 +70,7 @@ config ARM select HARDIRQS_SW_RESEND select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 - select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU + select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU && !PREEMPT_RT select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL select HAVE_ARCH_MMAP_RND_BITS if MMU @@ -110,6 +111,7 @@ config ARM select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_PREEMPT_LAZY select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RSEQ @@ -125,6 +127,7 @@ config ARM select OLD_SIGSUSPEND3 select PCI_SYSCALL if PCI select PERF_USE_VMALLOC + select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM select RTC_LIB select SET_FS select SYS_SUPPORTS_APM_EMULATION diff --git a/arch/arm/include/asm/spinlock_types.h b/arch/arm/include/asm/spinlock_types.h index 5976958647fe..0c14b36ef101 100644 --- a/arch/arm/include/asm/spinlock_types.h +++ b/arch/arm/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef __ASM_SPINLOCK_TYPES_H #define __ASM_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index 70d4cbc49ae1..b86418b4dfef 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -54,6 +54,7 @@ struct cpu_context_save { struct thread_info { unsigned long flags; /* low level flags */ int preempt_count; /* 0 => preemptable, <0 => bug */ + int preempt_lazy_count; /* 0 => preemptable, <0 => bug */ mm_segment_t addr_limit; /* address limit */ struct task_struct *task; /* main task structure */ __u32 cpu; /* cpu */ @@ -146,6 +147,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, #define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */ #define TIF_SECCOMP 7 /* seccomp syscall filtering active */ #define TIF_NOTIFY_SIGNAL 8 /* signal notifications exist */ +#define TIF_NEED_RESCHED_LAZY 9 #define TIF_USING_IWMMXT 17 #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ @@ -160,6 +162,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) +#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT) /* Checks for any syscall work in entry-common.S */ @@ -169,7 +172,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *, /* * Change these and you break ASM code in entry-common.S */ -#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ +#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | \ + _TIF_SIGPENDING | \ _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ _TIF_NOTIFY_SIGNAL) diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 70993af22d80..024c65c3a0f2 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -43,6 +43,7 @@ int main(void) BLANK(); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count)); + DEFINE(TI_PREEMPT_LAZY, offsetof(struct thread_info, preempt_lazy_count)); DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit)); DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 0ea8529a4872..fa0d155d21b3 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -206,11 +206,18 @@ __irq_svc: #ifdef CONFIG_PREEMPTION ldr r8, [tsk, #TI_PREEMPT] @ get preempt count - ldr r0, [tsk, #TI_FLAGS] @ get flags teq r8, #0 @ if preempt count != 0 + bne 1f @ return from exeption + ldr r0, [tsk, #TI_FLAGS] @ get flags + tst r0, #_TIF_NEED_RESCHED @ if NEED_RESCHED is set + blne svc_preempt @ preempt! + + ldr r8, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count + teq r8, #0 @ if preempt lazy count != 0 movne r0, #0 @ force flags to 0 - tst r0, #_TIF_NEED_RESCHED + tst r0, #_TIF_NEED_RESCHED_LAZY blne svc_preempt +1: #endif svc_exit r5, irq = 1 @ return from exception @@ -225,8 +232,14 @@ svc_preempt: 1: bl preempt_schedule_irq @ irq en/disable is done inside ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS tst r0, #_TIF_NEED_RESCHED + bne 1b + tst r0, #_TIF_NEED_RESCHED_LAZY reteq r8 @ go again - b 1b + ldr r0, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count + teq r0, #0 @ if preempt lazy count != 0 + beq 1b + ret r8 @ go again + #endif __und_fault: diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a3a38d0a4c85..f04ccf19ab1f 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -649,7 +649,8 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) */ trace_hardirqs_off(); do { - if (likely(thread_flags & _TIF_NEED_RESCHED)) { + if (likely(thread_flags & (_TIF_NEED_RESCHED | + _TIF_NEED_RESCHED_LAZY))) { schedule(); } else { if (unlikely(!user_mode(regs))) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index c7bb168b0d97..b943e2df9540 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -667,9 +667,7 @@ static void do_handle_IPI(int ipinr) break; case IPI_CPU_BACKTRACE: - printk_nmi_enter(); nmi_cpu_backtrace(get_irq_regs()); - printk_nmi_exit(); break; default: diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index da78740faf7b..07f79e533a29 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -400,6 +400,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr, if (addr < TASK_SIZE) return do_page_fault(addr, fsr, regs); + if (interrupts_enabled(regs)) + local_irq_enable(); + if (user_mode(regs)) goto bad_area; @@ -479,6 +482,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr, static int do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { + if (interrupts_enabled(regs)) + local_irq_enable(); + do_bad_area(addr, fsr, regs); return 0; } diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 62c3c1d2190f..ae8e49784705 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -88,6 +88,7 @@ config ARM64 select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG) select ARCH_SUPPORTS_NUMA_BALANCING + select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT select ARCH_WANT_DEFAULT_BPF_JIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT @@ -194,6 +195,7 @@ config ARM64 select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_PREEMPT_LAZY select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_FUTEX_CMPXCHG if FUTEX select MMU_GATHER_RCU_TABLE_FREE @@ -215,6 +217,7 @@ config ARM64 select PCI_DOMAINS_GENERIC if PCI select PCI_ECAM if (ACPI && PCI) select PCI_SYSCALL if PCI + select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM select POWER_RESET select POWER_SUPPLY select SPARSE_IRQ diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 16e53d251508..4a1bf6309e38 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1001,7 +1001,7 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, */ static inline bool arch_faults_on_old_pte(void) { - WARN_ON(preemptible()); + WARN_ON(is_migratable()); return !cpu_has_hw_af(); } diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h index e83f0982b99c..2545c17281e1 100644 --- a/arch/arm64/include/asm/preempt.h +++ b/arch/arm64/include/asm/preempt.h @@ -70,13 +70,36 @@ static inline bool __preempt_count_dec_and_test(void) * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE * pair. */ - return !pc || !READ_ONCE(ti->preempt_count); + if (!pc || !READ_ONCE(ti->preempt_count)) + return true; +#ifdef CONFIG_PREEMPT_LAZY + if ((pc & ~PREEMPT_NEED_RESCHED)) + return false; + if (current_thread_info()->preempt_lazy_count) + return false; + return test_thread_flag(TIF_NEED_RESCHED_LAZY); +#else + return false; +#endif } static inline bool should_resched(int preempt_offset) { +#ifdef CONFIG_PREEMPT_LAZY + u64 pc = READ_ONCE(current_thread_info()->preempt_count); + if (pc == preempt_offset) + return true; + + if ((pc & ~PREEMPT_NEED_RESCHED) != preempt_offset) + return false; + + if (current_thread_info()->preempt_lazy_count) + return false; + return test_thread_flag(TIF_NEED_RESCHED_LAZY); +#else u64 pc = READ_ONCE(current_thread_info()->preempt_count); return pc == preempt_offset; +#endif } #ifdef CONFIG_PREEMPTION diff --git a/arch/arm64/include/asm/spinlock_types.h b/arch/arm64/include/asm/spinlock_types.h index 18782f0c4721..11ab1c077697 100644 --- a/arch/arm64/include/asm/spinlock_types.h +++ b/arch/arm64/include/asm/spinlock_types.h @@ -5,7 +5,7 @@ #ifndef __ASM_SPINLOCK_TYPES_H #define __ASM_SPINLOCK_TYPES_H -#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H) +#if !defined(__LINUX_SPINLOCK_TYPES_RAW_H) && !defined(__ASM_SPINLOCK_H) # error "please don't include this file directly" #endif diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 6623c99f0984..c55ccec33a5a 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -26,6 +26,7 @@ struct thread_info { #ifdef CONFIG_ARM64_SW_TTBR0_PAN u64 ttbr0; /* saved TTBR0_EL1 */ #endif + int preempt_lazy_count; /* 0 => preemptable, <0 => bug */ union { u64 preempt_count; /* 0 => preemptible, <0 => bug */ struct { @@ -67,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst, #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */ #define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */ #define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */ +#define TIF_NEED_RESCHED_LAZY 7 #define TIF_SYSCALL_TRACE 8 /* syscall trace active */ #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */ #define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */ @@ -97,8 +99,10 @@ int arch_dup_task_struct(struct task_struct *dst, #define _TIF_SVE (1 << TIF_SVE) #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) +#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) -#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ +#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | \ + _TIF_SIGPENDING | \ _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ _TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \ _TIF_NOTIFY_SIGNAL) @@ -107,6 +111,8 @@ int arch_dup_task_struct(struct task_struct *dst, _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \ _TIF_SYSCALL_EMU) +#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY) + #ifdef CONFIG_SHADOW_CALL_STACK #define INIT_SCS \ .scs_base = init_shadow_call_stack, \ diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index c85670692afa..51586f98eb13 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -31,6 +31,7 @@ int main(void) BLANK(); DEFINE(TSK_TI_FLAGS, offsetof(struct task_struct, thread_info.flags)); DEFINE(TSK_TI_PREEMPT, offsetof(struct task_struct, thread_info.preempt_count)); + DEFINE(TSK_TI_PREEMPT_LAZY, offsetof(struct task_struct, thread_info.preempt_lazy_count)); #ifdef CONFIG_ARM64_SW_TTBR0_PAN DEFINE(TSK_TI_TTBR0, offsetof(struct task_struct, thread_info.ttbr0)); #endif diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 3599b9a2f1df..f1665b1b2d38 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -177,10 +177,19 @@ static void __get_cpu_fpsimd_context(void) * * The double-underscore version must only be called if you know the task * can't be preempted. + * + * On RT kernels local_bh_disable() is not sufficient because it only + * serializes soft interrupt related sections via a local lock, but stays + * preemptible. Disabling preemption is the right choice here as bottom + * half processing is always in thread context on RT kernels so it + * implicitly prevents bottom half processing as well. */ static void get_cpu_fpsimd_context(void) { - local_bh_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_disable(); + else + preempt_disable(); __get_cpu_fpsimd_context(); } @@ -201,7 +210,10 @@ static void __put_cpu_fpsimd_context(void) static void put_cpu_fpsimd_context(void) { __put_cpu_fpsimd_context(); - local_bh_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_enable(); + else + preempt_enable(); } static bool have_cpu_fpsimd_context(void) @@ -1033,6 +1045,7 @@ void fpsimd_thread_switch(struct task_struct *next) void fpsimd_flush_thread(void) { int vl, supported_vl; + void *sve_state = NULL; if (!system_supports_fpsimd()) return; @@ -1045,7 +1058,10 @@ void fpsimd_flush_thread(void) if (system_supports_sve()) { clear_thread_flag(TIF_SVE); - sve_free(current); + + /* Defer kfree() while in atomic context */ + sve_state = current->thread.sve_state; + current->thread.sve_state = NULL; /* * Reset the task vector length as required. @@ -1079,6 +1095,7 @@ void fpsimd_flush_thread(void) } put_cpu_fpsimd_context(); + kfree(sve_state); } /* diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 23036334f4dc..4c41672af805 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -929,7 +929,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) { do { - if (thread_flags & _TIF_NEED_RESCHED) { + if (thread_flags & _TIF_NEED_RESCHED_MASK) { /* Unmask Debug and SError for the next task */ local_daif_restore(DAIF_PROCCTX_NOIRQ); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 45ee8abcf202..02981e08fee7 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -773,7 +773,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) * involves poking the GIC, which must be done in a * non-preemptible context. */ - preempt_disable(); + migrate_disable(); kvm_pmu_flush_hwstate(vcpu); @@ -822,7 +822,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_timer_sync_user(vcpu); kvm_vgic_sync_hwstate(vcpu); local_irq_enable(); - preempt_enable(); + migrate_enable(); continue; } @@ -894,7 +894,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) /* Exit types that need handling before we can be preempted */ handle_exit_early(vcpu, ret); - preempt_enable(); + migrate_enable(); /* * The ARMv8 architecture doesn't give the hypervisor diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h index 8ff0f6ff3a00..db87a12c3827 100644 --- a/arch/csky/include/asm/spinlock_types.h +++ b/arch/csky/include/asm/spinlock_types.h @@ -3,7 +3,7 @@ #ifndef __ASM_CSKY_SPINLOCK_TYPES_H #define __ASM_CSKY_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/hexagon/include/asm/spinlock_types.h b/arch/hexagon/include/asm/spinlock_types.h index 19d233497ba5..d5f66495b670 100644 --- a/arch/hexagon/include/asm/spinlock_types.h +++ b/arch/hexagon/include/asm/spinlock_types.h @@ -8,7 +8,7 @@ #ifndef _ASM_SPINLOCK_TYPES_H #define _ASM_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/ia64/include/asm/spinlock_types.h b/arch/ia64/include/asm/spinlock_types.h index 6e345fefcdca..14b8a161c165 100644 --- a/arch/ia64/include/asm/spinlock_types.h +++ b/arch/ia64/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef _ASM_IA64_SPINLOCK_TYPES_H #define _ASM_IA64_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index d4d274bb07ff..b9e2a8087f02 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -153,6 +153,7 @@ config PPC select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select ARCH_STACKWALK select ARCH_SUPPORTS_ATOMIC_RMW + select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK select ARCH_SUPPORTS_DEBUG_PAGEALLOC if PPC_BOOK3S || PPC_8xx || 40x select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if PPC64 @@ -223,6 +224,7 @@ config PPC select HAVE_IOREMAP_PROT select HAVE_IRQ_EXIT_ON_IRQ_STACK select HAVE_IRQ_TIME_ACCOUNTING + select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM select HAVE_KERNEL_GZIP select HAVE_KERNEL_LZMA if DEFAULT_UIMAGE select HAVE_KERNEL_LZO if DEFAULT_UIMAGE @@ -239,6 +241,7 @@ config PPC select HAVE_PERF_EVENTS_NMI if PPC64 select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_PREEMPT_LAZY select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE select HAVE_RSEQ diff --git a/arch/powerpc/include/asm/simple_spinlock_types.h b/arch/powerpc/include/asm/simple_spinlock_types.h index 0f3cdd8faa95..08243338069d 100644 --- a/arch/powerpc/include/asm/simple_spinlock_types.h +++ b/arch/powerpc/include/asm/simple_spinlock_types.h @@ -2,7 +2,7 @@ #ifndef _ASM_POWERPC_SIMPLE_SPINLOCK_TYPES_H #define _ASM_POWERPC_SIMPLE_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index 03b3d010cbab..eec452e647b3 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -58,6 +58,7 @@ struct smp_ops_t { extern int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us); extern int smp_send_safe_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us); +extern void smp_send_debugger_break_cpu(unsigned int cpu); extern void smp_send_debugger_break(void); extern void start_secondary_resume(void); extern void smp_generic_give_timebase(void); diff --git a/arch/powerpc/include/asm/spinlock_types.h b/arch/powerpc/include/asm/spinlock_types.h index c5d742f18021..d5f8a74ed2e8 100644 --- a/arch/powerpc/include/asm/spinlock_types.h +++ b/arch/powerpc/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef _ASM_POWERPC_SPINLOCK_TYPES_H #define _ASM_POWERPC_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h index 1c8460e23583..b1653c160bab 100644 --- a/arch/powerpc/include/asm/stackprotector.h +++ b/arch/powerpc/include/asm/stackprotector.h @@ -24,7 +24,11 @@ static __always_inline void boot_init_stack_canary(void) unsigned long canary; /* Try to get a semi random initial value. */ +#ifdef CONFIG_PREEMPT_RT + canary = (unsigned long)&canary; +#else canary = get_random_canary(); +#endif canary ^= mftb(); canary ^= LINUX_VERSION_CODE; canary &= CANARY_MASK; diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index b4ec6c7dd72e..07df83231ec2 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -47,6 +47,8 @@ struct thread_info { int preempt_count; /* 0 => preemptable, <0 => BUG */ + int preempt_lazy_count; /* 0 => preemptable, + <0 => BUG */ unsigned long local_flags; /* private flags for thread */ #ifdef CONFIG_LIVEPATCH unsigned long *livepatch_sp; @@ -93,6 +95,7 @@ void arch_setup_new_exec(void); #define TIF_PATCH_PENDING 6 /* pending live patching update */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SINGLESTEP 8 /* singlestepping active */ +#define TIF_NEED_RESCHED_LAZY 9 /* lazy rescheduling necessary */ #define TIF_SECCOMP 10 /* secure computing */ #define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */ #define TIF_NOERROR 12 /* Force successful syscall return */ @@ -108,6 +111,7 @@ void arch_setup_new_exec(void); #define TIF_POLLING_NRFLAG 19 /* true if poll_idle() is polling TIF_NEED_RESCHED */ #define TIF_32BIT 20 /* 32 bit binary */ + /* as above, but as bit values */ #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE) #define _TIF_SIGPENDING (1<<TIF_SIGPENDING) @@ -119,6 +123,7 @@ void arch_setup_new_exec(void); #define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING) #define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT) #define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP) +#define _TIF_NEED_RESCHED_LAZY (1<<TIF_NEED_RESCHED_LAZY) #define _TIF_SECCOMP (1<<TIF_SECCOMP) #define _TIF_RESTOREALL (1<<TIF_RESTOREALL) #define _TIF_NOERROR (1<<TIF_NOERROR) @@ -132,10 +137,12 @@ void arch_setup_new_exec(void); _TIF_SYSCALL_EMU) #define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \ + _TIF_NEED_RESCHED_LAZY | \ _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ _TIF_RESTORE_TM | _TIF_PATCH_PENDING | \ _TIF_NOTIFY_SIGNAL) #define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR) +#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY) /* Bits in local_flags */ /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */ diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index 795bf682ec71..e7a3d6e4924e 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -348,7 +348,7 @@ again: ti_flags = READ_ONCE(current_thread_info()->flags); while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) { local_irq_enable(); - if (ti_flags & _TIF_NEED_RESCHED) { + if (ti_flags & _TIF_NEED_RESCHED_MASK) { schedule(); } else { /* @@ -558,11 +558,15 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) /* Returning to a kernel context with local irqs enabled. */ WARN_ON_ONCE(!(regs->msr & MSR_EE)); again: - if (IS_ENABLED(CONFIG_PREEMPT)) { + if (IS_ENABLED(CONFIG_PREEMPTION)) { /* Return to preemptible kernel context */ if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED)) { if (preempt_count() == 0) preempt_schedule_irq(); + } else if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED_LAZY)) { + if ((preempt_count() == 0) && + (current_thread_info()->preempt_lazy_count == 0)) + preempt_schedule_irq(); } } diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 551b653228c4..2a226cad6449 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -684,6 +684,7 @@ static inline void check_stack_overflow(void) } } +#ifndef CONFIG_PREEMPT_RT static __always_inline void call_do_softirq(const void *sp) { /* Temporarily switch r1 to sp, call __do_softirq() then restore r1. */ @@ -702,6 +703,7 @@ static __always_inline void call_do_softirq(const void *sp) "r11", "r12" ); } +#endif static __always_inline void call_do_irq(struct pt_regs *regs, void *sp) { @@ -814,10 +816,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_mostly; void *softirq_ctx[NR_CPUS] __read_mostly; void *hardirq_ctx[NR_CPUS] __read_mostly; +#ifndef CONFIG_PREEMPT_RT void do_softirq_own_stack(void) { call_do_softirq(softirq_ctx[smp_processor_id()]); } +#endif irq_hw_number_t virq_to_hw(unsigned int virq) { diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index bdee7262c080..d57d37497862 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -120,11 +120,19 @@ int kgdb_skipexception(int exception, struct pt_regs *regs) static int kgdb_debugger_ipi(struct pt_regs *regs) { - kgdb_nmicallback(raw_smp_processor_id(), regs); + int cpu = raw_smp_processor_id(); + + if (!kgdb_roundup_delay(cpu)) + kgdb_nmicallback(cpu, regs); return 0; } #ifdef CONFIG_SMP +void kgdb_roundup_cpu(unsigned int cpu) +{ + smp_send_debugger_break_cpu(cpu); +} + void kgdb_roundup_cpus(void) { smp_send_debugger_break(); diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 3c5eb9dc101b..a22bf94a3342 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -582,6 +582,11 @@ static void debugger_ipi_callback(struct pt_regs *regs) debugger_ipi(regs); } +void smp_send_debugger_break_cpu(unsigned int cpu) +{ + smp_send_nmi_ipi(cpu, debugger_ipi_callback, 1000000); +} + void smp_send_debugger_break(void) { smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, debugger_ipi_callback, 1000000); diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 08356ec9bfed..c875056873cb 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -171,7 +171,6 @@ extern void panic_flush_kmsg_start(void) extern void panic_flush_kmsg_end(void) { - printk_safe_flush_on_panic(); kmsg_dump(KMSG_DUMP_PANIC); bust_spinlocks(0); debug_locks_off(); @@ -261,12 +260,17 @@ static char *get_mmu_str(void) static int __die(const char *str, struct pt_regs *regs, long err) { + const char *pr = ""; + printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter); + if (IS_ENABLED(CONFIG_PREEMPTION)) + pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT"; + printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n", IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE", PAGE_SIZE / 1024, get_mmu_str(), - IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "", + pr, IS_ENABLED(CONFIG_SMP) ? " SMP" : "", IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "", debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "", diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index a165635fd214..f9ea0e5357f9 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -184,11 +184,6 @@ static void watchdog_smp_panic(int cpu, u64 tb) wd_smp_unlock(&flags); - printk_safe_flush(); - /* - * printk_safe_flush() seems to require another print - * before anything actually goes out to console. - */ if (sysctl_hardlockup_all_cpu_backtrace) trigger_allbutself_cpu_backtrace(); diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index 10f997e6bb95..d5359701f787 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -312,9 +312,6 @@ void default_machine_crash_shutdown(struct pt_regs *regs) unsigned int i; int (*old_handler)(struct pt_regs *regs); - /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */ - printk_nmi_enter(); - /* * This function is only called after the system * has panicked or is otherwise in a critical state. diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index e45644657d49..b826174ce983 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -179,6 +179,7 @@ config KVM_E500MC config KVM_MPIC bool "KVM in-kernel MPIC emulation" depends on KVM && E500 + depends on !PREEMPT_RT select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQFD select HAVE_KVM_IRQ_ROUTING diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 0c55b991f665..b529370fb27a 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -24,6 +24,7 @@ #include <linux/of.h> #include <linux/iommu.h> #include <linux/rculist.h> +#include <linux/local_lock.h> #include <asm/io.h> #include <asm/prom.h> #include <asm/rtas.h> @@ -190,7 +191,13 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift, return ret; } -static DEFINE_PER_CPU(__be64 *, tce_page); +struct tce_page { + __be64 * page; + local_lock_t lock; +}; +static DEFINE_PER_CPU(struct tce_page, tce_page) = { + .lock = INIT_LOCAL_LOCK(lock), +}; static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long npages, unsigned long uaddr, @@ -212,9 +219,10 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, direction, attrs); } - local_irq_save(flags); /* to protect tcep and the page behind it */ + /* to protect tcep and the page behind it */ + local_lock_irqsave(&tce_page.lock, flags); - tcep = __this_cpu_read(tce_page); + tcep = __this_cpu_read(tce_page.page); /* This is safe to do since interrupts are off when we're called * from iommu_alloc{,_sg}() @@ -223,12 +231,12 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcep = (__be64 *)__get_free_page(GFP_ATOMIC); /* If allocation fails, fall back to the loop implementation */ if (!tcep) { - local_irq_restore(flags); + local_unlock_irqrestore(&tce_page.lock, flags); return tce_build_pSeriesLP(tbl->it_index, tcenum, tbl->it_page_shift, npages, uaddr, direction, attrs); } - __this_cpu_write(tce_page, tcep); + __this_cpu_write(tce_page.page, tcep); } rpn = __pa(uaddr) >> TCE_SHIFT; @@ -258,7 +266,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcenum += limit; } while (npages > 0 && !rc); - local_irq_restore(flags); + local_unlock_irqrestore(&tce_page.lock, flags); if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) { ret = (int)rc; @@ -429,16 +437,17 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, DMA_BIDIRECTIONAL, 0); } - local_irq_disable(); /* to protect tcep and the page behind it */ - tcep = __this_cpu_read(tce_page); + /* to protect tcep and the page behind it */ + local_lock_irq(&tce_page.lock); + tcep = __this_cpu_read(tce_page.page); if (!tcep) { tcep = (__be64 *)__get_free_page(GFP_ATOMIC); if (!tcep) { - local_irq_enable(); + local_unlock_irq(&tce_page.lock); return -ENOMEM; } - __this_cpu_write(tce_page, tcep); + __this_cpu_write(tce_page.page, tcep); } proto_tce = TCE_PCI_READ | TCE_PCI_WRITE; @@ -481,7 +490,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, /* error cleanup: caller will clear whole range */ - local_irq_enable(); + local_unlock_irq(&tce_page.lock); return rc; } diff --git a/arch/riscv/include/asm/spinlock_types.h b/arch/riscv/include/asm/spinlock_types.h index f398e7638dd6..5a35a49505da 100644 --- a/arch/riscv/include/asm/spinlock_types.h +++ b/arch/riscv/include/asm/spinlock_types.h @@ -6,7 +6,7 @@ #ifndef _ASM_RISCV_SPINLOCK_TYPES_H #define _ASM_RISCV_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/s390/include/asm/spinlock_types.h b/arch/s390/include/asm/spinlock_types.h index a2bbfd7df85f..b69695e39957 100644 --- a/arch/s390/include/asm/spinlock_types.h +++ b/arch/s390/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef __ASM_SPINLOCK_TYPES_H #define __ASM_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/sh/include/asm/spinlock_types.h b/arch/sh/include/asm/spinlock_types.h index e82369f286a2..907bda4b1619 100644 --- a/arch/sh/include/asm/spinlock_types.h +++ b/arch/sh/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef __ASM_SH_SPINLOCK_TYPES_H #define __ASM_SH_SPINLOCK_TYPES_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c index ef0f0827cf57..2d3eca8fee01 100644 --- a/arch/sh/kernel/irq.c +++ b/arch/sh/kernel/irq.c @@ -149,6 +149,7 @@ void irq_ctx_exit(int cpu) hardirq_ctx[cpu] = NULL; } +#ifndef CONFIG_PREEMPT_RT void do_softirq_own_stack(void) { struct thread_info *curctx; @@ -176,6 +177,7 @@ void do_softirq_own_stack(void) "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr" ); } +#endif #else static inline void handle_one_irq(unsigned int irq) { diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c index c8848bb681a1..41fa1be980a3 100644 --- a/arch/sparc/kernel/irq_64.c +++ b/arch/sparc/kernel/irq_64.c @@ -855,6 +855,7 @@ void __irq_entry handler_irq(int pil, struct pt_regs *regs) set_irq_regs(old_regs); } +#ifndef CONFIG_PREEMPT_RT void do_softirq_own_stack(void) { void *orig_sp, *sp = softirq_stack[smp_processor_id()]; @@ -869,6 +870,7 @@ void do_softirq_own_stack(void) __asm__ __volatile__("mov %0, %%sp" : : "r" (orig_sp)); } +#endif #ifdef CONFIG_HOTPLUG_CPU void fixup_irqs(void) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c925f182a194..619d5c398d56 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -107,6 +107,7 @@ config X86 select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 select ARCH_SUPPORTS_LTO_CLANG select ARCH_SUPPORTS_LTO_CLANG_THIN + select ARCH_SUPPORTS_RT select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_MEMTEST select ARCH_USE_QUEUED_RWLOCKS @@ -231,6 +232,7 @@ config X86 select HAVE_PCI select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_PREEMPT_LAZY select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT select HAVE_POSIX_CPU_TIMERS_TASK_WORK select HAVE_REGS_AND_STACK_ACCESS_API diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 23bef08a8388..62cf3e4c06fb 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -28,6 +28,7 @@ extern void kernel_fpu_begin_mask(unsigned int kfpu_mask); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); extern void fpregs_mark_activate(void); +extern void kernel_fpu_resched(void); /* Code that is unaware of kernel_fpu_begin_mask() can use this */ static inline void kernel_fpu_begin(void) diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h index 8d55bd11848c..f755c217f67b 100644 --- a/arch/x86/include/asm/irq_stack.h +++ b/arch/x86/include/asm/irq_stack.h @@ -201,6 +201,7 @@ IRQ_CONSTRAINTS, regs, vector); \ } +#ifndef CONFIG_PREEMPT_RT /* * Macro to invoke __do_softirq on the irq stack. This is only called from * task context when bottom halves are about to be reenabled and soft @@ -214,6 +215,8 @@ __this_cpu_write(hardirq_stack_inuse, false); \ } +#endif + #else /* CONFIG_X86_64 */ /* System vector handlers always run on the stack they interrupted. */ #define run_sysvec_on_irqstack_cond(func, regs) \ diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index fe5efbcba824..ab8cb5fc2329 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -90,17 +90,48 @@ static __always_inline void __preempt_count_sub(int val) * a decrement which hits zero means we have no preempt_count and should * reschedule. */ -static __always_inline bool __preempt_count_dec_and_test(void) +static __always_inline bool ____preempt_count_dec_and_test(void) { return GEN_UNARY_RMWcc("decl", __preempt_count, e, __percpu_arg([var])); } +static __always_inline bool __preempt_count_dec_and_test(void) +{ + if (____preempt_count_dec_and_test()) + return true; +#ifdef CONFIG_PREEMPT_LAZY + if (preempt_count()) + return false; + if (current_thread_info()->preempt_lazy_count) + return false; + return test_thread_flag(TIF_NEED_RESCHED_LAZY); +#else + return false; +#endif +} + /* * Returns true when we need to resched and can (barring IRQ state). */ static __always_inline bool should_resched(int preempt_offset) { +#ifdef CONFIG_PREEMPT_LAZY + u32 tmp; + tmp = raw_cpu_read_4(__preempt_count); + if (tmp == preempt_offset) + return true; + + /* preempt count == 0 ? */ + tmp &= ~PREEMPT_NEED_RESCHED; + if (tmp != preempt_offset) + return false; + /* XXX PREEMPT_LOCK_OFFSET */ + if (current_thread_info()->preempt_lazy_count) + return false; + return test_thread_flag(TIF_NEED_RESCHED_LAZY); +#else return unlikely(raw_cpu_read_4(__preempt_count) == preempt_offset); +#endif } #ifdef CONFIG_PREEMPTION diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h index 6fd8410a3910..f3bf2f515edb 100644 --- a/arch/x86/include/asm/signal.h +++ b/arch/x86/include/asm/signal.h @@ -28,6 +28,19 @@ typedef struct { #define SA_IA32_ABI 0x02000000u #define SA_X32_ABI 0x01000000u +/* + * Because some traps use the IST stack, we must keep preemption + * disabled while calling do_trap(), but do_trap() may call + * force_sig_info() which will grab the signal spin_locks for the + * task, which in PREEMPT_RT are mutexes. By defining + * ARCH_RT_DELAYS_SIGNAL_SEND the force_sig_info() will set + * TIF_NOTIFY_RESUME and set up the signal to be sent on exit of the + * trap. + */ +#if defined(CONFIG_PREEMPT_RT) +#define ARCH_RT_DELAYS_SIGNAL_SEND +#endif + #ifndef CONFIG_COMPAT typedef sigset_t compat_sigset_t; #endif diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index 24a8d6c4fb18..2fc22c27df18 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -50,7 +50,7 @@ */ static __always_inline void boot_init_stack_canary(void) { - u64 canary; + u64 canary = 0; u64 tsc; #ifdef CONFIG_X86_64 @@ -61,8 +61,14 @@ static __always_inline void boot_init_stack_canary(void) * of randomness. The TSC only matters for very early init, * there it already has some randomness on most systems. Later * on during the bootup the random pool has true entropy too. + * For preempt-rt we need to weaken the randomness a bit, as + * we can't call into the random generator from atomic context + * due to locking constraints. We just leave canary + * uninitialized and use the TSC based randomness on top of it. */ +#ifndef CONFIG_PREEMPT_RT get_random_bytes(&canary, sizeof(canary)); +#endif tsc = rdtsc(); canary += tsc + (tsc << 32UL); canary &= CANARY_MASK; diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index de406d93b515..53d0ddd2586a 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -57,11 +57,14 @@ struct thread_info { unsigned long flags; /* low level flags */ unsigned long syscall_work; /* SYSCALL_WORK_ flags */ u32 status; /* thread synchronous flags */ + int preempt_lazy_count; /* 0 => lazy preemptable + <0 => BUG */ }; #define INIT_THREAD_INFO(tsk) \ { \ .flags = 0, \ + .preempt_lazy_count = 0, \ } #else /* !__ASSEMBLY__ */ @@ -90,6 +93,7 @@ struct thread_info { #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_NOTIFY_SIGNAL 17 /* signal notifications exist */ #define TIF_SLD 18 /* Restore split lock detection on context switch */ +#define TIF_NEED_RESCHED_LAZY 19 /* lazy rescheduling necessary */ #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ @@ -113,6 +117,7 @@ struct thread_info { #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) #define _TIF_SLD (1 << TIF_SLD) +#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index ba54c44a64e2..7b587f8d5aa5 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -81,11 +81,12 @@ EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler); DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0) { struct pt_regs *old_regs = set_irq_regs(regs); + u64 ip = regs ? instruction_pointer(regs) : 0; inc_irq_stat(hyperv_stimer0_count); if (hv_stimer0_handler) hv_stimer0_handler(); - add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0); + add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0, ip); ack_APIC_irq(); set_irq_regs(old_regs); diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index 722fd712e1cf..82cc3a7be6bd 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -141,7 +141,7 @@ recursion_check: */ if (visit_mask) { if (*visit_mask & (1UL << info->type)) { - printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); + pr_warn_once("WARNING: stack recursion on stack type %d\n", info->type); goto unknown; } *visit_mask |= 1UL << info->type; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 6c5defd6569a..5f725b0ceb29 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -207,7 +207,8 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, if (visit_mask) { if (*visit_mask & (1UL << info->type)) { if (task == current) - printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); + pr_warn_once("WARNING: stack recursion on stack type %d\n", + info->type); goto unknown; } *visit_mask |= 1UL << info->type; diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 7ada7bd03a32..e17fe40ee51e 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -185,6 +185,18 @@ void kernel_fpu_end(void) } EXPORT_SYMBOL_GPL(kernel_fpu_end); +void kernel_fpu_resched(void) +{ + WARN_ON_FPU(!this_cpu_read(in_kernel_fpu)); + + if (should_resched(PREEMPT_OFFSET)) { + kernel_fpu_end(); + cond_resched(); + kernel_fpu_begin(); + } +} +EXPORT_SYMBOL_GPL(kernel_fpu_resched); + /* * Sync the FPU register state to current's memory register state when the * current task owns the FPU. The hardware register state is preserved. diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c index 282b4ee1339f..161bcf35014d 100644 --- a/arch/x86/kernel/i8259.c +++ b/arch/x86/kernel/i8259.c @@ -207,8 +207,7 @@ spurious_8259A_irq: * lets ACK and report it. [once per IRQ] */ if (!(spurious_irq_mask & irqmask)) { - printk_deferred(KERN_DEBUG - "spurious 8259A interrupt: IRQ%d.\n", irq); + printk(KERN_DEBUG "spurious 8259A interrupt: IRQ%d.\n", irq); spurious_irq_mask |= irqmask; } atomic_inc(&irq_err_count); diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 044902d5a3c4..e5dd6da78713 100644 --- a/arch/x86/kernel/irq_32.c +++ b/arch/x86/kernel/irq_32.c @@ -132,6 +132,7 @@ int irq_init_percpu_irqstack(unsigned int cpu) return 0; } +#ifndef CONFIG_PREEMPT_RT void do_softirq_own_stack(void) { struct irq_stack *irqstk; @@ -148,6 +149,7 @@ void do_softirq_own_stack(void) call_on_stack(__do_softirq, isp); } +#endif void __handle_irq(struct irq_desc *desc, struct pt_regs *regs) { diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 3a43a2dee658..37bd37cdf2b6 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -502,9 +502,12 @@ static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs) if (atomic_read(&kgdb_active) != -1) { /* KGDB CPU roundup */ cpu = raw_smp_processor_id(); - kgdb_nmicallback(cpu, regs); - set_bit(cpu, was_in_debug_nmi); - touch_nmi_watchdog(); + + if (!kgdb_roundup_delay(cpu)) { + kgdb_nmicallback(cpu, regs); + set_bit(cpu, was_in_debug_nmi); + touch_nmi_watchdog(); + } return NMI_HANDLED; } diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index d7c44b257f7f..2d0361cd304f 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -41,9 +41,9 @@ static void unwind_dump(struct unwind_state *state) dumped_before = true; - printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n", - state->stack_info.type, state->stack_info.next_sp, - state->stack_mask, state->graph_idx); + printk("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n", + state->stack_info.type, state->stack_info.next_sp, + state->stack_mask, state->graph_idx); for (sp = PTR_ALIGN(state->orig_sp, sizeof(long)); sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { @@ -59,13 +59,11 @@ static void unwind_dump(struct unwind_state *state) if (zero) { if (!prev_zero) - printk_deferred("%p: %0*x ...\n", - sp, BITS_PER_LONG/4, 0); + printk("%p: %0*x ...\n", sp, BITS_PER_LONG/4, 0); continue; } - printk_deferred("%p: %0*lx (%pB)\n", - sp, BITS_PER_LONG/4, word, (void *)word); + printk("%p: %0*lx (%pB)\n", sp, BITS_PER_LONG/4, word, (void *)word); } } } @@ -342,13 +340,13 @@ bad_address: goto the_end; if (state->regs) { - printk_deferred_once(KERN_WARNING + pr_warn_once( "WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n", state->regs, state->task->comm, state->task->pid, next_bp); unwind_dump(state); } else { - printk_deferred_once(KERN_WARNING + pr_warn_once( "WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n", state->bp, state->task->comm, state->task->pid, next_bp); diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index a1202536fc57..a26a7c3849f5 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -9,7 +9,7 @@ #include <asm/orc_lookup.h> #define orc_warn(fmt, ...) \ - printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__) + pr_warn_once("WARNING: " fmt, ##__VA_ARGS__) #define orc_warn_current(args...) \ ({ \ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 599ed79581bf..775fb903a311 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8485,6 +8485,14 @@ int kvm_arch_init(void *opaque) goto out; } +#ifdef CONFIG_PREEMPT_RT + if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { + pr_err("RT requires X86_FEATURE_CONSTANT_TSC\n"); + r = -EOPNOTSUPP; + goto out; + } +#endif + r = -ENOMEM; x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu), __alignof__(struct fpu), SLAB_ACCOUNT, diff --git a/arch/xtensa/include/asm/spinlock_types.h b/arch/xtensa/include/asm/spinlock_types.h index 64c9389254f1..797aed7df3dd 100644 --- a/arch/xtensa/include/asm/spinlock_types.h +++ b/arch/xtensa/include/asm/spinlock_types.h @@ -2,7 +2,7 @@ #ifndef __ASM_SPINLOCK_TYPES_H #define __ASM_SPINLOCK_TYPES_H -#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H) +#if !defined(__LINUX_SPINLOCK_TYPES_RAW_H) && !defined(__ASM_SPINLOCK_H) # error "please don't include this file directly" #endif diff --git a/block/blk-mq.c b/block/blk-mq.c index 5a5dbb3d0875..bd2d2be28e78 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1556,14 +1556,14 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, return; if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { - int cpu = get_cpu(); + int cpu = get_cpu_light(); if (cpumask_test_cpu(cpu, hctx->cpumask)) { __blk_mq_run_hw_queue(hctx); - put_cpu(); + put_cpu_light(); return; } - put_cpu(); + put_cpu_light(); } kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, diff --git a/crypto/cryptd.c b/crypto/cryptd.c index a1bea0f4baa8..5f8ca8c1f59c 100644 --- a/crypto/cryptd.c +++ b/crypto/cryptd.c @@ -36,6 +36,7 @@ static struct workqueue_struct *cryptd_wq; struct cryptd_cpu_queue { struct crypto_queue queue; struct work_struct work; + spinlock_t qlock; }; struct cryptd_queue { @@ -105,6 +106,7 @@ static int cryptd_init_queue(struct cryptd_queue *queue, cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu); crypto_init_queue(&cpu_queue->queue, max_cpu_qlen); INIT_WORK(&cpu_queue->work, cryptd_queue_worker); + spin_lock_init(&cpu_queue->qlock); } pr_info("cryptd: max_cpu_qlen set to %d\n", max_cpu_qlen); return 0; @@ -129,8 +131,10 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue, struct cryptd_cpu_queue *cpu_queue; refcount_t *refcnt; - cpu = get_cpu(); - cpu_queue = this_cpu_ptr(queue->cpu_queue); + cpu_queue = raw_cpu_ptr(queue->cpu_queue); + spin_lock_bh(&cpu_queue->qlock); + cpu = smp_processor_id(); + err = crypto_enqueue_request(&cpu_queue->queue, request); refcnt = crypto_tfm_ctx(request->tfm); @@ -146,7 +150,7 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue, refcount_inc(refcnt); out_put_cpu: - put_cpu(); + spin_unlock_bh(&cpu_queue->qlock); return err; } @@ -162,16 +166,11 @@ static void cryptd_queue_worker(struct work_struct *work) cpu_queue = container_of(work, struct cryptd_cpu_queue, work); /* * Only handle one request at a time to avoid hogging crypto workqueue. - * preempt_disable/enable is used to prevent being preempted by - * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent - * cryptd_enqueue_request() being accessed from software interrupts. */ - local_bh_disable(); - preempt_disable(); + spin_lock_bh(&cpu_queue->qlock); backlog = crypto_get_backlog(&cpu_queue->queue); req = crypto_dequeue_request(&cpu_queue->queue); - preempt_enable(); - local_bh_enable(); + spin_unlock_bh(&cpu_queue->qlock); if (!req) return; diff --git a/crypto/testmgr.c b/crypto/testmgr.c index c978e41f11a1..3ef88ed3811e 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -1061,14 +1061,14 @@ static void generate_random_testvec_config(struct testvec_config *cfg, static void crypto_disable_simd_for_test(void) { - preempt_disable(); + migrate_disable(); __this_cpu_write(crypto_simd_disabled_for_test, true); } static void crypto_reenable_simd_for_test(void) { __this_cpu_write(crypto_simd_disabled_for_test, false); - preempt_enable(); + migrate_enable(); } /* diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 6383c81ac5b3..abb695f5f5e4 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -59,6 +59,40 @@ static void zram_free_page(struct zram *zram, size_t index); static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, u32 index, int offset, struct bio *bio); +#ifdef CONFIG_PREEMPT_RT +static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) +{ + size_t index; + + for (index = 0; index < num_pages; index++) + spin_lock_init(&zram->table[index].lock); +} + +static int zram_slot_trylock(struct zram *zram, u32 index) +{ + int ret; + + ret = spin_trylock(&zram->table[index].lock); + if (ret) + __set_bit(ZRAM_LOCK, &zram->table[index].flags); + return ret; +} + +static void zram_slot_lock(struct zram *zram, u32 index) +{ + spin_lock(&zram->table[index].lock); + __set_bit(ZRAM_LOCK, &zram->table[index].flags); +} + +static void zram_slot_unlock(struct zram *zram, u32 index) +{ + __clear_bit(ZRAM_LOCK, &zram->table[index].flags); + spin_unlock(&zram->table[index].lock); +} + +#else + +static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { } static int zram_slot_trylock(struct zram *zram, u32 index) { @@ -74,6 +108,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index) { bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags); } +#endif static inline bool init_done(struct zram *zram) { @@ -1169,6 +1204,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize) if (!huge_class_size) huge_class_size = zs_huge_class_size(zram->mem_pool); + zram_meta_init_table_locks(zram, num_pages); return true; } diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 80c3b43b4828..d8f6d880f915 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -63,6 +63,7 @@ struct zram_table_entry { unsigned long element; }; unsigned long flags; + spinlock_t lock; #ifdef CONFIG_ZRAM_MEMORY_TRACKING ktime_t ac_time; #endif diff --git a/drivers/char/random.c b/drivers/char/random.c index 605969ed0f96..56b2d5a7e2a0 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1242,26 +1242,25 @@ static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs) return *ptr; } -void add_interrupt_randomness(int irq, int irq_flags) +void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) { struct entropy_store *r; struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness); - struct pt_regs *regs = get_irq_regs(); unsigned long now = jiffies; cycles_t cycles = random_get_entropy(); __u32 c_high, j_high; - __u64 ip; if (cycles == 0) - cycles = get_reg(fast_pool, regs); + cycles = get_reg(fast_pool, NULL); c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0; j_high = (sizeof(now) > 4) ? now >> 32 : 0; fast_pool->pool[0] ^= cycles ^ j_high ^ irq; fast_pool->pool[1] ^= now ^ c_high; - ip = regs ? instruction_pointer(regs) : _RET_IP_; + if (!ip) + ip = _RET_IP_; fast_pool->pool[2] ^= ip; fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 : - get_reg(fast_pool, regs); + get_reg(fast_pool, NULL); fast_mix(fast_pool); add_interrupt_bench(cycles); @@ -1507,9 +1506,8 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, print_once = true; #endif if (__ratelimit(&unseeded_warning)) - printk_deferred(KERN_NOTICE "random: %s called from %pS " - "with crng_init=%d\n", func_name, caller, - crng_init); + pr_notice("random: %s called from %pS with crng_init=%d\n", + func_name, caller, crng_init); } /* diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c index d3f2e5364c27..9c4a99757afd 100644 --- a/drivers/char/tpm/tpm_tis.c +++ b/drivers/char/tpm/tpm_tis.c @@ -50,6 +50,31 @@ static inline struct tpm_tis_tcg_phy *to_tpm_tis_tcg_phy(struct tpm_tis_data *da return container_of(data, struct tpm_tis_tcg_phy, priv); } +#ifdef CONFIG_PREEMPT_RT +/* + * Flushes previous write operations to chip so that a subsequent + * ioread*()s won't stall a cpu. + */ +static inline void tpm_tis_flush(void __iomem *iobase) +{ + ioread8(iobase + TPM_ACCESS(0)); +} +#else +#define tpm_tis_flush(iobase) do { } while (0) +#endif + +static inline void tpm_tis_iowrite8(u8 b, void __iomem *iobase, u32 addr) +{ + iowrite8(b, iobase + addr); + tpm_tis_flush(iobase); +} + +static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr) +{ + iowrite32(b, iobase + addr); + tpm_tis_flush(iobase); +} + static int interrupts = -1; module_param(interrupts, int, 0444); MODULE_PARM_DESC(interrupts, "Enable interrupts"); @@ -169,7 +194,7 @@ static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data); while (len--) - iowrite8(*value++, phy->iobase + addr); + tpm_tis_iowrite8(*value++, phy->iobase, addr); return 0; } @@ -196,7 +221,7 @@ static int tpm_tcg_write32(struct tpm_tis_data *data, u32 addr, u32 value) { struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data); - iowrite32(value, phy->iobase + addr); + tpm_tis_iowrite32(value, phy->iobase, addr); return 0; } diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 847f33ffc4ae..ae79c3300129 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -66,7 +66,7 @@ struct mm_struct efi_mm = { struct workqueue_struct *efi_rts_wq; -static bool disable_runtime; +static bool disable_runtime = IS_ENABLED(CONFIG_PREEMPT_RT); static int __init setup_noefi(char *arg) { disable_runtime = true; @@ -97,6 +97,9 @@ static int __init parse_efi_cmdline(char *str) if (parse_option_str(str, "noruntime")) disable_runtime = true; + if (parse_option_str(str, "runtime")) + disable_runtime = false; + if (parse_option_str(str, "nosoftreserve")) set_bit(EFI_MEM_NO_SOFT_RESERVE, &efi.flags); diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c index 95ff1707b4bd..cea166e12777 100644 --- a/drivers/gpu/drm/i915/display/intel_crtc.c +++ b/drivers/gpu/drm/i915/display/intel_crtc.c @@ -425,7 +425,8 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state) */ intel_psr_wait_for_idle(new_crtc_state); - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); crtc->debug.min_vbl = min; crtc->debug.max_vbl = max; @@ -450,11 +451,13 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state) break; } - local_irq_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); timeout = schedule_timeout(timeout); - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); } finish_wait(wq, &wait); @@ -487,7 +490,8 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state) return; irq_disable: - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); } #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE) @@ -566,7 +570,8 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state) new_crtc_state->uapi.event = NULL; } - local_irq_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); /* Send VRR Push to terminate Vblank */ intel_vrr_send_push(new_crtc_state); diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index 38cc42783dfb..594dec2f7695 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -318,10 +318,9 @@ void __intel_breadcrumbs_park(struct intel_breadcrumbs *b) /* Kick the work once more to drain the signalers, and disarm the irq */ irq_work_sync(&b->irq_work); while (READ_ONCE(b->irq_armed) && !atomic_read(&b->active)) { - local_irq_disable(); - signal_irq_work(&b->irq_work); - local_irq_enable(); + irq_work_queue(&b->irq_work); cond_resched(); + irq_work_sync(&b->irq_work); } } diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c index 47f4397095e5..0361ef2fb614 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -84,9 +84,10 @@ static int __engine_unpark(struct intel_wakeref *wf) static unsigned long __timeline_mark_lock(struct intel_context *ce) { - unsigned long flags; + unsigned long flags = 0; - local_irq_save(flags); + if (!force_irqthreads) + local_irq_save(flags); mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_); return flags; @@ -96,7 +97,8 @@ static void __timeline_mark_unlock(struct intel_context *ce, unsigned long flags) { mutex_release(&ce->timeline->mutex.dep_map, _THIS_IP_); - local_irq_restore(flags); + if (!force_irqthreads) + local_irq_restore(flags); } #else diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 4bf1fdd93344..0eee93724bda 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -1265,7 +1265,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * and context switches) submission. */ - spin_lock(&engine->active.lock); + spin_lock_irq(&engine->active.lock); /* * If the queue is higher priority than the last @@ -1365,7 +1365,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * Even if ELSP[1] is occupied and not worthy * of timeslices, our queue might be. */ - spin_unlock(&engine->active.lock); + spin_unlock_irq(&engine->active.lock); return; } } @@ -1391,7 +1391,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if (last && !can_merge_rq(last, rq)) { spin_unlock(&ve->base.active.lock); - spin_unlock(&engine->active.lock); + spin_unlock_irq(&engine->active.lock); return; /* leave this for another sibling */ } @@ -1552,7 +1552,7 @@ done: * interrupt for secondary ports). */ execlists->queue_priority_hint = queue_prio(execlists); - spin_unlock(&engine->active.lock); + spin_unlock_irq(&engine->active.lock); /* * We can skip poking the HW if we ended up with exactly the same set @@ -1578,13 +1578,6 @@ done: } } -static void execlists_dequeue_irq(struct intel_engine_cs *engine) -{ - local_irq_disable(); /* Suspend interrupts across request submission */ - execlists_dequeue(engine); - local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */ -} - static void clear_ports(struct i915_request **ports, int count) { memset_p((void **)ports, NULL, count); @@ -2373,7 +2366,7 @@ static void execlists_submission_tasklet(struct tasklet_struct *t) } if (!engine->execlists.pending[0]) { - execlists_dequeue_irq(engine); + execlists_dequeue(engine); start_timeslice(engine); } diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index c3816f5c6900..54414b7b62dd 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -887,6 +887,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, spin_lock_irqsave(&dev_priv->uncore.lock, irqflags); /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */ + preempt_disable_rt(); /* Get optional system timestamp before query. */ if (stime) @@ -951,6 +952,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, *etime = ktime_get(); /* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */ + preempt_enable_rt(); spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags); diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h index 6778ad2a14a4..df253a9cc719 100644 --- a/drivers/gpu/drm/i915/i915_trace.h +++ b/drivers/gpu/drm/i915/i915_trace.h @@ -2,6 +2,10 @@ #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ) #define _I915_TRACE_H_ +#ifdef CONFIG_PREEMPT_RT +#define NOTRACE +#endif + #include <linux/stringify.h> #include <linux/types.h> #include <linux/tracepoint.h> @@ -817,7 +821,7 @@ DEFINE_EVENT(i915_request, i915_request_add, TP_ARGS(rq) ); -#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) +#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) && !defined(NOTRACE) DEFINE_EVENT(i915_request, i915_request_submit, TP_PROTO(struct i915_request *rq), TP_ARGS(rq) diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c index 573154268d43..9a08bc8e1f12 100644 --- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -1814,6 +1814,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, struct radeon_device *rdev = dev->dev_private; /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */ + preempt_disable_rt(); /* Get optional system timestamp before query. */ if (stime) @@ -1906,6 +1907,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, *etime = ktime_get(); /* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */ + preempt_enable_rt(); /* Decode into vertical and horizontal scanout position. */ *vpos = position & 0x1fff; diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index d030577ad6a2..ef1db3367df7 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -19,6 +19,7 @@ #include <linux/atomic.h> #include <linux/hyperv.h> #include <linux/interrupt.h> +#include <linux/irq.h> #include "hv_trace.h" diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 57bbbaa4e8f7..bd3fcf38811f 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -22,6 +22,7 @@ #include <linux/clockchips.h> #include <linux/cpu.h> #include <linux/sched/task_stack.h> +#include <linux/irq.h> #include <linux/delay.h> #include <linux/notifier.h> @@ -1340,6 +1341,8 @@ static void vmbus_isr(void) void *page_addr = hv_cpu->synic_event_page; struct hv_message *msg; union hv_synic_event_flags *event; + struct pt_regs *regs = get_irq_regs(); + u64 ip = regs ? instruction_pointer(regs) : 0; bool handled = false; if (unlikely(page_addr == NULL)) @@ -1384,7 +1387,7 @@ static void vmbus_isr(void) tasklet_schedule(&hv_cpu->msg_dpc); } - add_interrupt_randomness(vmbus_interrupt, 0); + add_interrupt_randomness(vmbus_interrupt, 0, ip); } static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id) diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig index b77a01bd27f4..aa74e2a05798 100644 --- a/drivers/leds/trigger/Kconfig +++ b/drivers/leds/trigger/Kconfig @@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT config LEDS_TRIGGER_CPU bool "LED CPU Trigger" + depends on !PREEMPT_RT help This allows LEDs to be controlled by active CPUs. This shows the active CPUs across an array of LEDs so you can see which diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index b8436e4930ed..5c5046f04ead 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2217,8 +2217,9 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) struct raid5_percpu *percpu; unsigned long cpu; - cpu = get_cpu(); + cpu = get_cpu_light(); percpu = per_cpu_ptr(conf->percpu, cpu); + spin_lock(&percpu->lock); if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) { ops_run_biofill(sh); overlap_clear++; @@ -2277,7 +2278,8 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) if (test_and_clear_bit(R5_Overlap, &dev->flags)) wake_up(&sh->raid_conf->wait_for_overlap); } - put_cpu(); + spin_unlock(&percpu->lock); + put_cpu_light(); } static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh) @@ -7102,6 +7104,7 @@ static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) __func__, cpu); return -ENOMEM; } + spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock); return 0; } diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index 5c05acf20e1f..665fe138ab4f 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -635,6 +635,7 @@ struct r5conf { int recovery_disabled; /* per cpu variables */ struct raid5_percpu { + spinlock_t lock; /* Protection for -RT */ struct page *spare_page; /* Used when checking P/Q in raid6 */ void *scribble; /* space for constructing buffer * lists and performing address diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c index 5ae6c207d3ac..660908027dc5 100644 --- a/drivers/scsi/fcoe/fcoe.c +++ b/drivers/scsi/fcoe/fcoe.c @@ -1450,11 +1450,11 @@ err2: static int fcoe_alloc_paged_crc_eof(struct sk_buff *skb, int tlen) { struct fcoe_percpu_s *fps; - int rc; + int rc, cpu = get_cpu_light(); - fps = &get_cpu_var(fcoe_percpu); + fps = &per_cpu(fcoe_percpu, cpu); rc = fcoe_get_paged_crc_eof(skb, tlen, fps); - put_cpu_var(fcoe_percpu); + put_cpu_light(); return rc; } @@ -1639,11 +1639,11 @@ static inline int fcoe_filter_frames(struct fc_lport *lport, return 0; } - stats = per_cpu_ptr(lport->stats, get_cpu()); + stats = per_cpu_ptr(lport->stats, get_cpu_light()); stats->InvalidCRCCount++; if (stats->InvalidCRCCount < 5) printk(KERN_WARNING "fcoe: dropping frame with CRC error\n"); - put_cpu(); + put_cpu_light(); return -EINVAL; } @@ -1684,7 +1684,7 @@ static void fcoe_recv_frame(struct sk_buff *skb) */ hp = (struct fcoe_hdr *) skb_network_header(skb); - stats = per_cpu_ptr(lport->stats, get_cpu()); + stats = per_cpu_ptr(lport->stats, get_cpu_light()); if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) { if (stats->ErrorFrames < 5) printk(KERN_WARNING "fcoe: FCoE version " @@ -1716,13 +1716,13 @@ static void fcoe_recv_frame(struct sk_buff *skb) goto drop; if (!fcoe_filter_frames(lport, fp)) { - put_cpu(); + put_cpu_light(); fc_exch_recv(lport, fp); return; } drop: stats->ErrorFrames++; - put_cpu(); + put_cpu_light(); kfree_skb(skb); } diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c index 1756a0ac6f08..3a2cbf35ea3d 100644 --- a/drivers/scsi/fcoe/fcoe_ctlr.c +++ b/drivers/scsi/fcoe/fcoe_ctlr.c @@ -828,7 +828,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip) INIT_LIST_HEAD(&del_list); - stats = per_cpu_ptr(fip->lp->stats, get_cpu()); + stats = per_cpu_ptr(fip->lp->stats, get_cpu_light()); list_for_each_entry_safe(fcf, next, &fip->fcfs, list) { deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2; @@ -864,7 +864,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip) sel_time = fcf->time; } } - put_cpu(); + put_cpu_light(); list_for_each_entry_safe(fcf, next, &del_list, list) { /* Removes fcf from current list */ diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c index 841000445b9a..26d661ddc950 100644 --- a/drivers/scsi/libfc/fc_exch.c +++ b/drivers/scsi/libfc/fc_exch.c @@ -825,10 +825,10 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport, } memset(ep, 0, sizeof(*ep)); - cpu = get_cpu(); + cpu = get_cpu_light(); pool = per_cpu_ptr(mp->pool, cpu); spin_lock_bh(&pool->lock); - put_cpu(); + put_cpu_light(); /* peek cache of free slot */ if (pool->left != FC_XID_UNKNOWN) { diff --git a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c index 6f5fe5092154..c8a625667e81 100644 --- a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c +++ b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c @@ -1904,8 +1904,8 @@ int __atomisp_streamoff(struct file *file, void *fh, enum v4l2_buf_type type) dev_dbg(isp->dev, "Stop stream on pad %d for asd%d\n", atomisp_subdev_source_pad(vdev), asd->index); - BUG_ON(!rt_mutex_is_locked(&isp->mutex)); - BUG_ON(!mutex_is_locked(&isp->streamoff_mutex)); + lockdep_assert_held(&isp->mutex); + lockdep_assert_held(&isp->streamoff_mutex); if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE) { dev_dbg(isp->dev, "unsupported v4l2 buf type\n"); diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 6473361525d1..2321d02e9b7a 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -132,12 +132,55 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value) up->dl_write(up, value); } +static inline void serial8250_set_IER(struct uart_8250_port *up, + unsigned char ier) +{ + struct uart_port *port = &up->port; + unsigned long flags; + bool is_console; + + is_console = uart_console(port); + + if (is_console) + console_atomic_lock(flags); + + serial_out(up, UART_IER, ier); + + if (is_console) + console_atomic_unlock(flags); +} + +static inline unsigned char serial8250_clear_IER(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + unsigned int clearval = 0; + unsigned long flags; + unsigned int prior; + bool is_console; + + is_console = uart_console(port); + + if (up->capabilities & UART_CAP_UUE) + clearval = UART_IER_UUE; + + if (is_console) + console_atomic_lock(flags); + + prior = serial_port_in(port, UART_IER); + serial_port_out(port, UART_IER, clearval); + + if (is_console) + console_atomic_unlock(flags); + + return prior; +} + static inline bool serial8250_set_THRI(struct uart_8250_port *up) { if (up->ier & UART_IER_THRI) return false; up->ier |= UART_IER_THRI; - serial_out(up, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); return true; } @@ -146,7 +189,7 @@ static inline bool serial8250_clear_THRI(struct uart_8250_port *up) if (!(up->ier & UART_IER_THRI)) return false; up->ier &= ~UART_IER_THRI; - serial_out(up, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); return true; } diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 1ce193daea7f..fad00c0414e3 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -264,10 +264,8 @@ static void serial8250_backup_timeout(struct timer_list *t) * Must disable interrupts or else we risk racing with the interrupt * based handler. */ - if (up->port.irq) { - ier = serial_in(up, UART_IER); - serial_out(up, UART_IER, 0); - } + if (up->port.irq) + ier = serial8250_clear_IER(up); iir = serial_in(up, UART_IIR); @@ -290,7 +288,7 @@ static void serial8250_backup_timeout(struct timer_list *t) serial8250_tx_chars(up); if (up->port.irq) - serial_out(up, UART_IER, ier); + serial8250_set_IER(up, ier); spin_unlock_irqrestore(&up->port.lock, flags); @@ -568,6 +566,14 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev) #ifdef CONFIG_SERIAL_8250_CONSOLE +static void univ8250_console_write_atomic(struct console *co, const char *s, + unsigned int count) +{ + struct uart_8250_port *up = &serial8250_ports[co->index]; + + serial8250_console_write_atomic(up, s, count); +} + static void univ8250_console_write(struct console *co, const char *s, unsigned int count) { @@ -661,6 +667,7 @@ static int univ8250_console_match(struct console *co, char *name, int idx, static struct console univ8250_console = { .name = "ttyS", + .write_atomic = univ8250_console_write_atomic, .write = univ8250_console_write, .device = uart_console_device, .setup = univ8250_console_setup, diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index fc65a2293ce9..19a92530040f 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -60,9 +60,18 @@ int fsl8250_handle_irq(struct uart_port *port) /* Stop processing interrupts on input overrun */ if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) { + unsigned long flags; unsigned long delay; + bool is_console; + is_console = uart_console(port); + + if (is_console) + console_atomic_lock(flags); up->ier = port->serial_in(port, UART_IER); + if (is_console) + console_atomic_unlock(flags); + if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { port->ops->stop_rx(port); } else { diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c index 988bf6bcce42..1e7468e6ccb1 100644 --- a/drivers/tty/serial/8250/8250_ingenic.c +++ b/drivers/tty/serial/8250/8250_ingenic.c @@ -146,6 +146,8 @@ OF_EARLYCON_DECLARE(x1000_uart, "ingenic,x1000-uart", static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value) { + unsigned long flags; + bool is_console; int ier; switch (offset) { @@ -167,7 +169,12 @@ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value) * If we have enabled modem status IRQs we should enable * modem mode. */ + is_console = uart_console(p); + if (is_console) + console_atomic_lock(flags); ier = p->serial_in(p, UART_IER); + if (is_console) + console_atomic_unlock(flags); if (ier & UART_IER_MSI) value |= UART_MCR_MDCE | UART_MCR_FCM; diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index fb65dc601b23..9af18b5d8296 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -218,12 +218,37 @@ static void mtk8250_shutdown(struct uart_port *port) static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask) { - serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask)); + struct uart_port *port = &up->port; + unsigned long flags; + unsigned int ier; + bool is_console; + + is_console = uart_console(port); + + if (is_console) + console_atomic_lock(flags); + + ier = serial_in(up, UART_IER); + serial_out(up, UART_IER, ier & (~mask)); + + if (is_console) + console_atomic_unlock(flags); } static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask) { - serial_out(up, UART_IER, serial_in(up, UART_IER) | mask); + struct uart_port *port = &up->port; + unsigned long flags; + unsigned int ier; + + if (uart_console(port)) + console_atomic_lock(flags); + + ier = serial_in(up, UART_IER); + serial_out(up, UART_IER, ier | mask); + + if (uart_console(port)) + console_atomic_unlock(flags); } static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index e4dd82fd7c2a..3c957489fc44 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -762,7 +762,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) serial_out(p, UART_EFR, UART_EFR_ECB); serial_out(p, UART_LCR, 0); } - serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0); + serial8250_set_IER(p, sleep ? UART_IERX_SLEEP : 0); if (p->capabilities & UART_CAP_EFR) { serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B); serial_out(p, UART_EFR, efr); @@ -1436,7 +1436,7 @@ static void serial8250_stop_rx(struct uart_port *port) up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); up->port.read_status_mask &= ~UART_LSR_DR; - serial_port_out(port, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); serial8250_rpm_put(up); } @@ -1466,7 +1466,7 @@ void serial8250_em485_stop_tx(struct uart_8250_port *p) serial8250_clear_and_reinit_fifos(p); p->ier |= UART_IER_RLSI | UART_IER_RDI; - serial_port_out(&p->port, UART_IER, p->ier); + serial8250_set_IER(p, p->ier); } } EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx); @@ -1688,7 +1688,7 @@ static void serial8250_disable_ms(struct uart_port *port) mctrl_gpio_disable_ms(up->gpios); up->ier &= ~UART_IER_MSI; - serial_port_out(port, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); } static void serial8250_enable_ms(struct uart_port *port) @@ -1704,7 +1704,7 @@ static void serial8250_enable_ms(struct uart_port *port) up->ier |= UART_IER_MSI; serial8250_rpm_get(up); - serial_port_out(port, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); serial8250_rpm_put(up); } @@ -2132,14 +2132,7 @@ static void serial8250_put_poll_char(struct uart_port *port, struct uart_8250_port *up = up_to_u8250p(port); serial8250_rpm_get(up); - /* - * First save the IER then disable the interrupts - */ - ier = serial_port_in(port, UART_IER); - if (up->capabilities & UART_CAP_UUE) - serial_port_out(port, UART_IER, UART_IER_UUE); - else - serial_port_out(port, UART_IER, 0); + ier = serial8250_clear_IER(up); wait_for_xmitr(up, BOTH_EMPTY); /* @@ -2152,7 +2145,7 @@ static void serial8250_put_poll_char(struct uart_port *port, * and restore the IER */ wait_for_xmitr(up, BOTH_EMPTY); - serial_port_out(port, UART_IER, ier); + serial8250_set_IER(up, ier); serial8250_rpm_put(up); } @@ -2455,7 +2448,7 @@ void serial8250_do_shutdown(struct uart_port *port) */ spin_lock_irqsave(&port->lock, flags); up->ier = 0; - serial_port_out(port, UART_IER, 0); + serial8250_set_IER(up, 0); spin_unlock_irqrestore(&port->lock, flags); synchronize_irq(port->irq); @@ -2837,7 +2830,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, if (up->capabilities & UART_CAP_RTOIE) up->ier |= UART_IER_RTOIE; - serial_port_out(port, UART_IER, up->ier); + serial8250_set_IER(up, up->ier); if (up->capabilities & UART_CAP_EFR) { unsigned char efr = 0; @@ -3303,7 +3296,7 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults); #ifdef CONFIG_SERIAL_8250_CONSOLE -static void serial8250_console_putchar(struct uart_port *port, int ch) +static void serial8250_console_putchar_locked(struct uart_port *port, int ch) { struct uart_8250_port *up = up_to_u8250p(port); @@ -3311,6 +3304,18 @@ static void serial8250_console_putchar(struct uart_port *port, int ch) serial_port_out(port, UART_TX, ch); } +static void serial8250_console_putchar(struct uart_port *port, int ch) +{ + struct uart_8250_port *up = up_to_u8250p(port); + unsigned long flags; + + wait_for_xmitr(up, UART_LSR_THRE); + + console_atomic_lock(flags); + serial8250_console_putchar_locked(port, ch); + console_atomic_unlock(flags); +} + /* * Restore serial console when h/w power-off detected */ @@ -3332,6 +3337,32 @@ static void serial8250_console_restore(struct uart_8250_port *up) serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS); } +void serial8250_console_write_atomic(struct uart_8250_port *up, + const char *s, unsigned int count) +{ + struct uart_port *port = &up->port; + unsigned long flags; + unsigned int ier; + + console_atomic_lock(flags); + + touch_nmi_watchdog(); + + ier = serial8250_clear_IER(up); + + if (atomic_fetch_inc(&up->console_printing)) { + uart_console_write(port, "\n", 1, + serial8250_console_putchar_locked); + } + uart_console_write(port, s, count, serial8250_console_putchar_locked); + atomic_dec(&up->console_printing); + + wait_for_xmitr(up, BOTH_EMPTY); + serial8250_set_IER(up, ier); + + console_atomic_unlock(flags); +} + /* * Print a string to the serial port trying not to disturb * any possible real use of the port... @@ -3348,24 +3379,12 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, struct uart_port *port = &up->port; unsigned long flags; unsigned int ier; - int locked = 1; touch_nmi_watchdog(); - if (oops_in_progress) - locked = spin_trylock_irqsave(&port->lock, flags); - else - spin_lock_irqsave(&port->lock, flags); - - /* - * First save the IER then disable the interrupts - */ - ier = serial_port_in(port, UART_IER); + spin_lock_irqsave(&port->lock, flags); - if (up->capabilities & UART_CAP_UUE) - serial_port_out(port, UART_IER, UART_IER_UUE); - else - serial_port_out(port, UART_IER, 0); + ier = serial8250_clear_IER(up); /* check scratch reg to see if port powered off during system sleep */ if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) { @@ -3379,7 +3398,9 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, mdelay(port->rs485.delay_rts_before_send); } + atomic_inc(&up->console_printing); uart_console_write(port, s, count, serial8250_console_putchar); + atomic_dec(&up->console_printing); /* * Finally, wait for transmitter to become empty @@ -3392,8 +3413,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, if (em485->tx_stopped) up->rs485_stop_tx(up); } - - serial_port_out(port, UART_IER, ier); + serial8250_set_IER(up, ier); /* * The receive handling will happen properly because the @@ -3405,8 +3425,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, if (up->msr_saved_flags) serial8250_modem_status(up); - if (locked) - spin_unlock_irqrestore(&port->lock, flags); + spin_unlock_irqrestore(&port->lock, flags); } static unsigned int probe_baud(struct uart_port *port) @@ -3426,6 +3445,7 @@ static unsigned int probe_baud(struct uart_port *port) int serial8250_console_setup(struct uart_port *port, char *options, bool probe) { + struct uart_8250_port *up = up_to_u8250p(port); int baud = 9600; int bits = 8; int parity = 'n'; @@ -3435,6 +3455,8 @@ int serial8250_console_setup(struct uart_port *port, char *options, bool probe) if (!port->iobase && !port->membase) return -ENODEV; + atomic_set(&up->console_printing, 0); + if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else if (probe) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index e14f3378b8a0..c722121bd7ca 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2199,18 +2199,24 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) { struct uart_amba_port *uap = amba_ports[co->index]; unsigned int old_cr = 0, new_cr; - unsigned long flags; + unsigned long flags = 0; int locked = 1; clk_enable(uap->clk); - local_irq_save(flags); + /* + * local_irq_save(flags); + * + * This local_irq_save() is nonsense. If we come in via sysrq + * handling then interrupts are already disabled. Aside of + * that the port.sysrq check is racy on SMP regardless. + */ if (uap->port.sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock(&uap->port.lock); + locked = spin_trylock_irqsave(&uap->port.lock, flags); else - spin_lock(&uap->port.lock); + spin_lock_irqsave(&uap->port.lock, flags); /* * First save the CR then disable the interrupts @@ -2236,8 +2242,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) pl011_write(old_cr, uap, REG_CR); if (locked) - spin_unlock(&uap->port.lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&uap->port.lock, flags); clk_disable(uap->clk); } diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index 9e81b09ba08e..0dd0e2223253 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1311,13 +1311,10 @@ serial_omap_console_write(struct console *co, const char *s, pm_runtime_get_sync(up->dev); - local_irq_save(flags); - if (up->port.sysrq) - locked = 0; - else if (oops_in_progress) - locked = spin_trylock(&up->port.lock); + if (up->port.sysrq || oops_in_progress) + locked = spin_trylock_irqsave(&up->port.lock, flags); else - spin_lock(&up->port.lock); + spin_lock_irqsave(&up->port.lock, flags); /* * First save the IER then disable the interrupts @@ -1346,8 +1343,7 @@ serial_omap_console_write(struct console *co, const char *s, pm_runtime_mark_last_busy(up->dev); pm_runtime_put_autosuspend(up->dev); if (locked) - spin_unlock(&up->port.lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&up->port.lock, flags); } static int __init diff --git a/drivers/virt/acrn/irqfd.c b/drivers/virt/acrn/irqfd.c index df5184979b28..d4ad211dce7a 100644 --- a/drivers/virt/acrn/irqfd.c +++ b/drivers/virt/acrn/irqfd.c @@ -17,7 +17,6 @@ #include "acrn_drv.h" static LIST_HEAD(acrn_irqfd_clients); -static DEFINE_MUTEX(acrn_irqfds_mutex); /** * struct hsm_irqfd - Properties of HSM irqfd diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c index dae9a57d7ec0..9a6a0ec4d1fb 100644 --- a/fs/afs/dir_silly.c +++ b/fs/afs/dir_silly.c @@ -239,7 +239,7 @@ int afs_silly_iput(struct dentry *dentry, struct inode *inode) struct dentry *alias; int ret; - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); _enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode); @@ -1695,7 +1695,7 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, list_del(&iocb->ki_list); iocb->ki_res.res = mangle_poll(mask); req->done = true; - if (iocb->ki_eventfd && eventfd_signal_count()) { + if (iocb->ki_eventfd && eventfd_signal_allowed()) { iocb = NULL; INIT_WORK(&req->work, aio_poll_put_work); schedule_work(&req->work); diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c index 54d77c99e21c..dc0626af4487 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -70,7 +70,7 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name, struct inode *inode; struct super_block *sb = parent->d_sb; struct cifs_sb_info *cifs_sb = CIFS_SB(sb); - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); cifs_dbg(FYI, "%s: for %s\n", __func__, name->name); diff --git a/fs/dcache.c b/fs/dcache.c index 9508bd57a3bc..654b4c9d4f8b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2539,9 +2539,10 @@ EXPORT_SYMBOL(d_rehash); static inline unsigned start_dir_add(struct inode *dir) { + preempt_disable_rt(); for (;;) { - unsigned n = dir->i_dir_seq; - if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n) + unsigned n = dir->__i_dir_seq; + if (!(n & 1) && cmpxchg(&dir->__i_dir_seq, n, n + 1) == n) return n; cpu_relax(); } @@ -2549,26 +2550,30 @@ static inline unsigned start_dir_add(struct inode *dir) static inline void end_dir_add(struct inode *dir, unsigned n) { - smp_store_release(&dir->i_dir_seq, n + 2); + smp_store_release(&dir->__i_dir_seq, n + 2); + preempt_enable_rt(); } static void d_wait_lookup(struct dentry *dentry) { - if (d_in_lookup(dentry)) { - DECLARE_WAITQUEUE(wait, current); - add_wait_queue(dentry->d_wait, &wait); - do { - set_current_state(TASK_UNINTERRUPTIBLE); - spin_unlock(&dentry->d_lock); - schedule(); - spin_lock(&dentry->d_lock); - } while (d_in_lookup(dentry)); - } + struct swait_queue __wait; + + if (!d_in_lookup(dentry)) + return; + + INIT_LIST_HEAD(&__wait.task_list); + do { + prepare_to_swait_exclusive(dentry->d_wait, &__wait, TASK_UNINTERRUPTIBLE); + spin_unlock(&dentry->d_lock); + schedule(); + spin_lock(&dentry->d_lock); + } while (d_in_lookup(dentry)); + finish_swait(dentry->d_wait, &__wait); } struct dentry *d_alloc_parallel(struct dentry *parent, const struct qstr *name, - wait_queue_head_t *wq) + struct swait_queue_head *wq) { unsigned int hash = name->hash; struct hlist_bl_head *b = in_lookup_hash(parent, hash); @@ -2582,7 +2587,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent, retry: rcu_read_lock(); - seq = smp_load_acquire(&parent->d_inode->i_dir_seq); + seq = smp_load_acquire(&parent->d_inode->__i_dir_seq); r_seq = read_seqbegin(&rename_lock); dentry = __d_lookup_rcu(parent, name, &d_seq); if (unlikely(dentry)) { @@ -2610,7 +2615,7 @@ retry: } hlist_bl_lock(b); - if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) { + if (unlikely(READ_ONCE(parent->d_inode->__i_dir_seq) != seq)) { hlist_bl_unlock(b); rcu_read_unlock(); goto retry; @@ -2683,7 +2688,7 @@ void __d_lookup_done(struct dentry *dentry) hlist_bl_lock(b); dentry->d_flags &= ~DCACHE_PAR_LOOKUP; __hlist_bl_del(&dentry->d_u.d_in_lookup_hash); - wake_up_all(dentry->d_wait); + swake_up_all(dentry->d_wait); dentry->d_wait = NULL; hlist_bl_unlock(b); INIT_HLIST_NODE(&dentry->d_u.d_alias); diff --git a/fs/eventfd.c b/fs/eventfd.c index e265b6dd4f34..3627dd7d25db 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -25,8 +25,6 @@ #include <linux/idr.h> #include <linux/uio.h> -DEFINE_PER_CPU(int, eventfd_wake_count); - static DEFINE_IDA(eventfd_ida); struct eventfd_ctx { @@ -67,21 +65,21 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) * Deadlock or stack overflow issues can happen if we recurse here * through waitqueue wakeup handlers. If the caller users potentially * nested waitqueues with custom wakeup handlers, then it should - * check eventfd_signal_count() before calling this function. If - * it returns true, the eventfd_signal() call should be deferred to a + * check eventfd_signal_allowed() before calling this function. If + * it returns false, the eventfd_signal() call should be deferred to a * safe context. */ - if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count))) + if (WARN_ON_ONCE(current->in_eventfd_signal)) return 0; spin_lock_irqsave(&ctx->wqh.lock, flags); - this_cpu_inc(eventfd_wake_count); + current->in_eventfd_signal = 1; if (ULLONG_MAX - ctx->count < n) n = ULLONG_MAX - ctx->count; ctx->count += n; if (waitqueue_active(&ctx->wqh)) wake_up_locked_poll(&ctx->wqh, EPOLLIN); - this_cpu_dec(eventfd_wake_count); + current->in_eventfd_signal = 0; spin_unlock_irqrestore(&ctx->wqh.lock, flags); return n; diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c index bc267832310c..3176913fae6c 100644 --- a/fs/fuse/readdir.c +++ b/fs/fuse/readdir.c @@ -158,7 +158,7 @@ static int fuse_direntplus_link(struct file *file, struct inode *dir = d_inode(parent); struct fuse_conn *fc; struct inode *inode; - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); if (!o->nodeid) { /* diff --git a/fs/inode.c b/fs/inode.c index 78de5b5dc084..646fe09ba5ec 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -157,7 +157,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_pipe = NULL; inode->i_cdev = NULL; inode->i_link = NULL; - inode->i_dir_seq = 0; + inode->__i_dir_seq = 0; inode->i_rdev = 0; inode->dirtied_when = 0; diff --git a/fs/namei.c b/fs/namei.c index bf6d8a738c59..96e507822b39 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1622,7 +1622,7 @@ static struct dentry *__lookup_slow(const struct qstr *name, { struct dentry *dentry, *old; struct inode *inode = dir->d_inode; - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); /* Don't go there if it's already dead */ if (unlikely(IS_DEADDIR(inode))) @@ -3140,7 +3140,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file, struct dentry *dentry; int error, create_error = 0; umode_t mode = op->mode; - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); if (unlikely(IS_DEADDIR(dir_inode))) return ERR_PTR(-ENOENT); diff --git a/fs/namespace.c b/fs/namespace.c index 74d756a79cb7..b3322390f4de 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -14,6 +14,7 @@ #include <linux/mnt_namespace.h> #include <linux/user_namespace.h> #include <linux/namei.h> +#include <linux/hrtimer.h> #include <linux/security.h> #include <linux/cred.h> #include <linux/idr.h> @@ -342,8 +343,11 @@ int __mnt_want_write(struct vfsmount *m) * incremented count after it has set MNT_WRITE_HOLD. */ smp_mb(); - while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) - cpu_relax(); + while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) { + preempt_enable(); + cpu_chill(); + preempt_disable(); + } /* * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will * be set to match its requirements. So we must not load that until diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 5b68c44848ca..85a1006e0a85 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -636,7 +636,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry, unsigned long dir_verifier) { struct qstr filename = QSTR_INIT(entry->name, entry->len); - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); struct dentry *dentry; struct dentry *alias; struct inode *inode; @@ -1875,7 +1875,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry, struct file *file, unsigned open_flags, umode_t mode) { - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); struct nfs_open_context *ctx; struct dentry *res; struct iattr attr = { .ia_valid = ATTR_OPEN }; diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c index 5fa11e1aca4c..984f26eb888c 100644 --- a/fs/nfs/unlink.c +++ b/fs/nfs/unlink.c @@ -13,7 +13,7 @@ #include <linux/sunrpc/clnt.h> #include <linux/nfs_fs.h> #include <linux/sched.h> -#include <linux/wait.h> +#include <linux/swait.h> #include <linux/namei.h> #include <linux/fsnotify.h> @@ -180,7 +180,7 @@ nfs_async_unlink(struct dentry *dentry, const struct qstr *name) data->cred = get_current_cred(); data->res.dir_attr = &data->dir_attr; - init_waitqueue_head(&data->wq); + init_swait_queue_head(&data->wq); status = -EBUSY; spin_lock(&dentry->d_lock); diff --git a/fs/proc/base.c b/fs/proc/base.c index 24a729d095c0..f57cb7122c6b 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -96,6 +96,7 @@ #include <linux/posix-timers.h> #include <linux/time_namespace.h> #include <linux/resctrl.h> +#include <linux/swait.h> #include <trace/events/oom.h> #include "internal.h" #include "fd.h" @@ -2040,7 +2041,7 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx, child = d_hash_and_lookup(dir, &qname); if (!child) { - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); child = d_alloc_parallel(dir, &qname, &wq); if (IS_ERR(child)) goto end_instantiate; diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 5d66faecd4ef..619d8e114646 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -678,7 +678,7 @@ static bool proc_sys_fill_cache(struct file *file, child = d_lookup(dir, &qname); if (!child) { - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq); child = d_alloc_parallel(dir, &qname, &wq); if (IS_ERR(child)) return false; diff --git a/include/asm-generic/softirq_stack.h b/include/asm-generic/softirq_stack.h index eceeecf6a5bd..d3e2d81656e0 100644 --- a/include/asm-generic/softirq_stack.h +++ b/include/asm-generic/softirq_stack.h @@ -2,7 +2,7 @@ #ifndef __ASM_GENERIC_SOFTIRQ_STACK_H #define __ASM_GENERIC_SOFTIRQ_STACK_H -#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK +#if defined(CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK) && !defined(CONFIG_PREEMPT_RT) void do_softirq_own_stack(void); #else static inline void do_softirq_own_stack(void) diff --git a/include/linux/console.h b/include/linux/console.h index a97f277cfdfa..487a4266ab2c 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -16,6 +16,13 @@ #include <linux/atomic.h> #include <linux/types.h> +#include <linux/printk.h> +#include <linux/seqlock.h> + +struct latched_seq { + seqcount_latch_t latch; + u64 val[2]; +}; struct vc_data; struct console_font_op; @@ -136,10 +143,12 @@ static inline int con_debug_leave(void) #define CON_ANYTIME (16) /* Safe to call when cpu is offline */ #define CON_BRL (32) /* Used for a braille device */ #define CON_EXTENDED (64) /* Use the extended output format a la /dev/kmsg */ +#define CON_HANDOVER (128) /* Device was previously a boot console. */ struct console { char name[16]; void (*write)(struct console *, const char *, unsigned); + void (*write_atomic)(struct console *co, const char *s, unsigned int count); int (*read)(struct console *, char *, unsigned); struct tty_driver *(*device)(struct console *, int *); void (*unblank)(void); @@ -149,6 +158,16 @@ struct console { short flags; short index; int cflag; +#ifdef CONFIG_PRINTK + char sync_buf[CONSOLE_LOG_MAX]; + struct latched_seq printk_seq; + struct latched_seq printk_sync_seq; +#ifdef CONFIG_HAVE_NMI + struct latched_seq printk_sync_nmi_seq; +#endif +#endif /* CONFIG_PRINTK */ + + struct task_struct *thread; uint ispeed; uint ospeed; void *data; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 9e23d33bb6f1..9f89d4887e35 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -108,7 +108,7 @@ struct dentry { union { struct list_head d_lru; /* LRU list */ - wait_queue_head_t *d_wait; /* in-lookup ones only */ + struct swait_queue_head *d_wait; /* in-lookup ones only */ }; struct list_head d_child; /* child of parent list */ struct list_head d_subdirs; /* our children */ @@ -240,7 +240,7 @@ extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op extern struct dentry * d_alloc(struct dentry *, const struct qstr *); extern struct dentry * d_alloc_anon(struct super_block *); extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, - wait_queue_head_t *); + struct swait_queue_head *); extern struct dentry * d_splice_alias(struct inode *, struct dentry *); extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); extern struct dentry * d_exact_alias(struct dentry *, struct inode *); diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h index edb5c186b0b7..3f49e65169c6 100644 --- a/include/linux/debug_locks.h +++ b/include/linux/debug_locks.h @@ -3,8 +3,7 @@ #define __LINUX_DEBUG_LOCKING_H #include <linux/atomic.h> -#include <linux/bug.h> -#include <linux/printk.h> +#include <linux/cache.h> struct task_struct; diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 2e2b8d6140ed..71064a2c2caf 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -57,9 +57,15 @@ # define ARCH_EXIT_TO_USER_MODE_WORK (0) #endif +#ifdef CONFIG_PREEMPT_LAZY +# define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY) +#else +# define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED) +#endif + #define EXIT_TO_USER_MODE_WORK \ (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \ - _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \ + _TIF_NEED_RESCHED_MASK | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \ ARCH_EXIT_TO_USER_MODE_WORK) /** diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index fa0a524baed0..305d5f19093b 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -14,6 +14,7 @@ #include <linux/err.h> #include <linux/percpu-defs.h> #include <linux/percpu.h> +#include <linux/sched.h> /* * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining @@ -43,11 +44,9 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w __u64 *cnt); void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); -DECLARE_PER_CPU(int, eventfd_wake_count); - -static inline bool eventfd_signal_count(void) +static inline bool eventfd_signal_allowed(void) { - return this_cpu_read(eventfd_wake_count); + return !current->in_eventfd_signal; } #else /* CONFIG_EVENTFD */ @@ -78,9 +77,9 @@ static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, return -ENOSYS; } -static inline bool eventfd_signal_count(void) +static inline bool eventfd_signal_allowed(void) { - return false; + return true; } static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) diff --git a/include/linux/fs.h b/include/linux/fs.h index ffeed3ccd2d6..aec0f7207209 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -699,7 +699,7 @@ struct inode { struct pipe_inode_info *i_pipe; struct cdev *i_cdev; char *i_link; - unsigned i_dir_seq; + unsigned __i_dir_seq; }; __u32 i_generation; diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 69bc86ea382c..76878b357ffa 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -116,7 +116,6 @@ extern void rcu_nmi_exit(void); do { \ lockdep_off(); \ arch_nmi_enter(); \ - printk_nmi_enter(); \ BUG_ON(in_nmi() == NMI_MASK); \ __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \ } while (0) @@ -135,7 +134,6 @@ extern void rcu_nmi_exit(void); do { \ BUG_ON(!in_nmi()); \ __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ - printk_nmi_exit(); \ arch_nmi_exit(); \ lockdep_on(); \ } while (0) diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h index 7902c7d8b55f..4aa1031d3e4c 100644 --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -90,7 +90,11 @@ static inline void __kunmap_local(void *vaddr) static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) { - preempt_disable(); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + migrate_disable(); + else + preempt_disable(); + pagefault_disable(); return __kmap_local_page_prot(page, prot); } @@ -102,7 +106,11 @@ static inline void *kmap_atomic(struct page *page) static inline void *kmap_atomic_pfn(unsigned long pfn) { - preempt_disable(); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + migrate_disable(); + else + preempt_disable(); + pagefault_disable(); return __kmap_local_pfn_prot(pfn, kmap_prot); } @@ -111,7 +119,10 @@ static inline void __kunmap_atomic(void *addr) { kunmap_local_indexed(addr); pagefault_enable(); - preempt_enable(); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + migrate_enable(); + else + preempt_enable(); } unsigned int __nr_free_highpages(void); @@ -179,7 +190,10 @@ static inline void __kunmap_local(void *addr) static inline void *kmap_atomic(struct page *page) { - preempt_disable(); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + migrate_disable(); + else + preempt_disable(); pagefault_disable(); return page_address(page); } @@ -200,7 +214,10 @@ static inline void __kunmap_atomic(void *addr) kunmap_flush_on_unmap(addr); #endif pagefault_enable(); - preempt_enable(); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + migrate_enable(); + else + preempt_enable(); } static inline unsigned int nr_free_highpages(void) { return 0; } diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 77295af72426..bf7fa1777b1b 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -42,6 +42,7 @@ enum hrtimer_mode { HRTIMER_MODE_PINNED = 0x02, HRTIMER_MODE_SOFT = 0x04, HRTIMER_MODE_HARD = 0x08, + HRTIMER_MODE_CHILL = 0x10, HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED, HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED, @@ -124,6 +125,7 @@ struct hrtimer { u8 is_rel; u8 is_soft; u8 is_hard; + u8 is_chill; }; /** @@ -535,4 +537,10 @@ int hrtimers_dead_cpu(unsigned int cpu); #define hrtimers_dead_cpu NULL #endif +#ifdef CONFIG_PREEMPT_RT +extern void cpu_chill(void); +#else +# define cpu_chill() cpu_relax() +#endif + #endif diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h index ec2a47a81e42..cfc3804ec9a0 100644 --- a/include/linux/irq_work.h +++ b/include/linux/irq_work.h @@ -3,6 +3,7 @@ #define _LINUX_IRQ_WORK_H #include <linux/smp_types.h> +#include <linux/rcuwait.h> /* * An entry can be in one of four states: @@ -16,11 +17,13 @@ struct irq_work { struct __call_single_node node; void (*func)(struct irq_work *); + struct rcuwait irqwait; }; #define __IRQ_WORK_INIT(_func, _flags) (struct irq_work){ \ .node = { .u_flags = (_flags), }, \ .func = (_func), \ + .irqwait = __RCUWAIT_INITIALIZER(irqwait), \ } #define IRQ_WORK_INIT(_func) __IRQ_WORK_INIT(_func, 0) @@ -46,6 +49,11 @@ static inline bool irq_work_is_busy(struct irq_work *work) return atomic_read(&work->node.a_flags) & IRQ_WORK_BUSY; } +static inline bool irq_work_is_hard(struct irq_work *work) +{ + return atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ; +} + bool irq_work_queue(struct irq_work *work); bool irq_work_queue_on(struct irq_work *work, int cpu); @@ -64,4 +72,10 @@ static inline void irq_work_run(void) { } static inline void irq_work_single(void *arg) { } #endif +#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT) +void irq_work_tick_soft(void); +#else +static inline void irq_work_tick_soft(void) { } +#endif + #endif /* _LINUX_IRQ_WORK_H */ diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 59aea39785bf..ab70314af3d5 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -68,6 +68,7 @@ struct irq_desc { unsigned int irqs_unhandled; atomic_t threads_handled; int threads_handled_last; + u64 random_ip; raw_spinlock_t lock; struct cpumask *percpu_enabled; const struct cpumask *percpu_affinity; diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 600c10da321a..4b140938b03e 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -71,14 +71,6 @@ do { \ do { \ __this_cpu_dec(hardirq_context); \ } while (0) -# define lockdep_softirq_enter() \ -do { \ - current->softirq_context++; \ -} while (0) -# define lockdep_softirq_exit() \ -do { \ - current->softirq_context--; \ -} while (0) # define lockdep_hrtimer_enter(__hrtimer) \ ({ \ @@ -140,6 +132,21 @@ do { \ # define lockdep_irq_work_exit(__work) do { } while (0) #endif +#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT) +# define lockdep_softirq_enter() \ +do { \ + current->softirq_context++; \ +} while (0) +# define lockdep_softirq_exit() \ +do { \ + current->softirq_context--; \ +} while (0) + +#else +# define lockdep_softirq_enter() do { } while (0) +# define lockdep_softirq_exit() do { } while (0) +#endif + #if defined(CONFIG_IRQSOFF_TRACER) || \ defined(CONFIG_PREEMPT_TRACER) extern void stop_critical_timings(void); diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 258cdde8d356..9bca0d98db5a 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -212,6 +212,8 @@ extern void kgdb_call_nmi_hook(void *ignored); */ extern void kgdb_roundup_cpus(void); +extern void kgdb_roundup_cpu(unsigned int cpu); + /** * kgdb_arch_set_pc - Generic call back to the program counter * @regs: Current &struct pt_regs. @@ -365,5 +367,6 @@ extern void kgdb_free_init_mem(void); #define dbg_late_init() static inline void kgdb_panic(const char *msg) {} static inline void kgdb_free_init_mem(void) { } +static inline void kgdb_roundup_cpu(unsigned int cpu) {} #endif /* ! CONFIG_KGDB */ #endif /* _KGDB_H_ */ diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h index 3f02b818625e..975e33b793a7 100644 --- a/include/linux/local_lock_internal.h +++ b/include/linux/local_lock_internal.h @@ -6,6 +6,8 @@ #include <linux/percpu-defs.h> #include <linux/lockdep.h> +#ifndef CONFIG_PREEMPT_RT + typedef struct { #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; @@ -95,3 +97,45 @@ do { \ local_lock_release(this_cpu_ptr(lock)); \ local_irq_restore(flags); \ } while (0) + +#else /* !CONFIG_PREEMPT_RT */ + +/* + * On PREEMPT_RT local_lock maps to a per CPU spinlock, which protects the + * critical section while staying preemptible. + */ +typedef spinlock_t local_lock_t; + +#define INIT_LOCAL_LOCK(lockname) __LOCAL_SPIN_LOCK_UNLOCKED((lockname)) + +#define __local_lock_init(l) \ + do { \ + local_spin_lock_init((l)); \ + } while (0) + +#define __local_lock(__lock) \ + do { \ + migrate_disable(); \ + spin_lock(this_cpu_ptr((__lock))); \ + } while (0) + +#define __local_lock_irq(lock) __local_lock(lock) + +#define __local_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + flags = 0; \ + __local_lock(lock); \ + } while (0) + +#define __local_unlock(__lock) \ + do { \ + spin_unlock(this_cpu_ptr((__lock))); \ + migrate_enable(); \ + } while (0) + +#define __local_unlock_irq(lock) __local_unlock(lock) + +#define __local_unlock_irqrestore(lock, flags) __local_unlock(lock) + +#endif /* CONFIG_PREEMPT_RT */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index aeb888d44805..0dbdfa4b78e2 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -12,6 +12,7 @@ #include <linux/completion.h> #include <linux/cpumask.h> #include <linux/uprobes.h> +#include <linux/rcupdate.h> #include <linux/page-flags-layout.h> #include <linux/workqueue.h> #include <linux/seqlock.h> @@ -566,6 +567,9 @@ struct mm_struct { bool tlb_flush_batched; #endif struct uprobes_state uprobes_state; +#ifdef CONFIG_PREEMPT_RT + struct rcu_head delayed_drop; +#endif #ifdef CONFIG_HUGETLB_PAGE atomic_long_t hugetlb_usage; #endif diff --git a/include/linux/mutex.h b/include/linux/mutex.h index e19323521f9c..8f226d460f51 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -20,8 +20,17 @@ #include <linux/osq_lock.h> #include <linux/debug_locks.h> -struct ww_class; -struct ww_acquire_ctx; +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ + , .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_SLEEP, \ + } +#else +# define __DEP_MAP_MUTEX_INITIALIZER(lockname) +#endif + +#ifndef CONFIG_PREEMPT_RT /* * Simple, straightforward mutexes with strict semantics: @@ -53,7 +62,7 @@ struct ww_acquire_ctx; */ struct mutex { atomic_long_t owner; - spinlock_t wait_lock; + raw_spinlock_t wait_lock; #ifdef CONFIG_MUTEX_SPIN_ON_OWNER struct optimistic_spin_queue osq; /* Spinner MCS lock */ #endif @@ -66,27 +75,6 @@ struct mutex { #endif }; -struct ww_mutex { - struct mutex base; - struct ww_acquire_ctx *ctx; -#ifdef CONFIG_DEBUG_MUTEXES - struct ww_class *ww_class; -#endif -}; - -/* - * This is the control structure for tasks blocked on mutex, - * which resides on the blocked task's kernel stack: - */ -struct mutex_waiter { - struct list_head list; - struct task_struct *task; - struct ww_acquire_ctx *ww_ctx; -#ifdef CONFIG_DEBUG_MUTEXES - void *magic; -#endif -}; - #ifdef CONFIG_DEBUG_MUTEXES #define __DEBUG_MUTEX_INITIALIZER(lockname) \ @@ -117,19 +105,9 @@ do { \ __mutex_init((mutex), #mutex, &__key); \ } while (0) -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ - , .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_SLEEP, \ - } -#else -# define __DEP_MAP_MUTEX_INITIALIZER(lockname) -#endif - #define __MUTEX_INITIALIZER(lockname) \ { .owner = ATOMIC_LONG_INIT(0) \ - , .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ + , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \ , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \ __DEBUG_MUTEX_INITIALIZER(lockname) \ __DEP_MAP_MUTEX_INITIALIZER(lockname) } @@ -148,6 +126,50 @@ extern void __mutex_init(struct mutex *lock, const char *name, */ extern bool mutex_is_locked(struct mutex *lock); +#else /* !CONFIG_PREEMPT_RT */ +/* + * Preempt-RT variant based on rtmutexes. + */ +#include <linux/rtmutex.h> + +struct mutex { + struct rt_mutex_base rtmutex; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +}; + +#define __MUTEX_INITIALIZER(mutexname) \ +{ \ + .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex) \ + __DEP_MAP_MUTEX_INITIALIZER(mutexname) \ +} + +#define DEFINE_MUTEX(mutexname) \ + struct mutex mutexname = __MUTEX_INITIALIZER(mutexname) + +extern void __mutex_rt_init(struct mutex *lock, const char *name, + struct lock_class_key *key); +extern int mutex_trylock(struct mutex *lock); + +static inline void mutex_destroy(struct mutex *lock) { } + +#define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) + +#define __mutex_init(mutex, name, key) \ +do { \ + rt_mutex_base_init(&(mutex)->rtmutex); \ + __mutex_rt_init((mutex), name, key); \ +} while (0) + +#define mutex_init(mutex) \ +do { \ + static struct lock_class_key __key; \ + \ + __mutex_init((mutex), #mutex, &__key); \ +} while (0) +#endif /* CONFIG_PREEMPT_RT */ + /* * See kernel/locking/mutex.c for detailed documentation of these APIs. * Also see Documentation/locking/mutex-design.rst. diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index aee1aa09702d..abb9b8d84420 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -1692,7 +1692,7 @@ struct nfs_unlinkdata { struct nfs_removeargs args; struct nfs_removeres res; struct dentry *dentry; - wait_queue_head_t wq; + struct swait_queue_head wq; const struct cred *cred; struct nfs_fattr dir_attr; long timeout; diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 2fb373a5c1ed..87069b8459af 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -168,8 +168,6 @@ extern int raw_notifier_call_chain(struct raw_notifier_head *nh, extern int srcu_notifier_call_chain(struct srcu_notifier_head *nh, unsigned long val, void *v); -extern int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh, - unsigned long val_up, unsigned long val_down, void *v); extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh, unsigned long val_up, unsigned long val_down, void *v); extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh, diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index c573fccfc475..612e28176d45 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -838,6 +838,15 @@ static inline int PageSlabPfmemalloc(struct page *page) return PageActive(page); } +/* + * A version of PageSlabPfmemalloc() for opportunistic checks where the page + * might have been freed under us and not be a PageSlab anymore. + */ +static inline int __PageSlabPfmemalloc(struct page *page) +{ + return PageActive(page); +} + static inline void SetPageSlabPfmemalloc(struct page *page) { VM_BUG_ON_PAGE(!PageSlab(page), page); diff --git a/include/linux/pid.h b/include/linux/pid.h index fa10acb8d6a4..2f86f84e9fc1 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -3,6 +3,7 @@ #define _LINUX_PID_H #include <linux/rculist.h> +#include <linux/atomic.h> #include <linux/wait.h> #include <linux/refcount.h> diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 9881eac0698f..af39859f02ee 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -121,7 +121,11 @@ /* * The preempt_count offset after spin_lock() */ +#if !defined(CONFIG_PREEMPT_RT) #define PREEMPT_LOCK_OFFSET PREEMPT_DISABLE_OFFSET +#else +#define PREEMPT_LOCK_OFFSET 0 +#endif /* * The preempt_count offset needed for things like: @@ -170,6 +174,20 @@ extern void preempt_count_sub(int val); #define preempt_count_inc() preempt_count_add(1) #define preempt_count_dec() preempt_count_sub(1) +#ifdef CONFIG_PREEMPT_LAZY +#define add_preempt_lazy_count(val) do { preempt_lazy_count() += (val); } while (0) +#define sub_preempt_lazy_count(val) do { preempt_lazy_count() -= (val); } while (0) +#define inc_preempt_lazy_count() add_preempt_lazy_count(1) +#define dec_preempt_lazy_count() sub_preempt_lazy_count(1) +#define preempt_lazy_count() (current_thread_info()->preempt_lazy_count) +#else +#define add_preempt_lazy_count(val) do { } while (0) +#define sub_preempt_lazy_count(val) do { } while (0) +#define inc_preempt_lazy_count() do { } while (0) +#define dec_preempt_lazy_count() do { } while (0) +#define preempt_lazy_count() (0) +#endif + #ifdef CONFIG_PREEMPT_COUNT #define preempt_disable() \ @@ -178,13 +196,25 @@ do { \ barrier(); \ } while (0) +#define preempt_lazy_disable() \ +do { \ + inc_preempt_lazy_count(); \ + barrier(); \ +} while (0) + #define sched_preempt_enable_no_resched() \ do { \ barrier(); \ preempt_count_dec(); \ } while (0) -#define preempt_enable_no_resched() sched_preempt_enable_no_resched() +#ifdef CONFIG_PREEMPT_RT +# define preempt_enable_no_resched() sched_preempt_enable_no_resched() +# define preempt_check_resched_rt() preempt_check_resched() +#else +# define preempt_enable_no_resched() preempt_enable() +# define preempt_check_resched_rt() barrier(); +#endif #define preemptible() (preempt_count() == 0 && !irqs_disabled()) @@ -209,6 +239,18 @@ do { \ __preempt_schedule(); \ } while (0) +/* + * open code preempt_check_resched() because it is not exported to modules and + * used by local_unlock() or bpf_enable_instrumentation(). + */ +#define preempt_lazy_enable() \ +do { \ + dec_preempt_lazy_count(); \ + barrier(); \ + if (should_resched(0)) \ + __preempt_schedule(); \ +} while (0) + #else /* !CONFIG_PREEMPTION */ #define preempt_enable() \ do { \ @@ -216,6 +258,12 @@ do { \ preempt_count_dec(); \ } while (0) +#define preempt_lazy_enable() \ +do { \ + dec_preempt_lazy_count(); \ + barrier(); \ +} while (0) + #define preempt_enable_notrace() \ do { \ barrier(); \ @@ -254,8 +302,12 @@ do { \ #define preempt_disable_notrace() barrier() #define preempt_enable_no_resched_notrace() barrier() #define preempt_enable_notrace() barrier() +#define preempt_check_resched_rt() barrier() #define preemptible() 0 +#define preempt_lazy_disable() barrier() +#define preempt_lazy_enable() barrier() + #endif /* CONFIG_PREEMPT_COUNT */ #ifdef MODULE @@ -274,10 +326,22 @@ do { \ } while (0) #define preempt_fold_need_resched() \ do { \ - if (tif_need_resched()) \ + if (tif_need_resched_now()) \ set_preempt_need_resched(); \ } while (0) +#ifdef CONFIG_PREEMPT_RT +# define preempt_disable_rt() preempt_disable() +# define preempt_enable_rt() preempt_enable() +# define preempt_disable_nort() barrier() +# define preempt_enable_nort() barrier() +#else +# define preempt_disable_rt() barrier() +# define preempt_enable_rt() barrier() +# define preempt_disable_nort() preempt_disable() +# define preempt_enable_nort() preempt_enable() +#endif + #ifdef CONFIG_PREEMPT_NOTIFIERS struct preempt_notifier; @@ -390,8 +454,15 @@ extern void migrate_enable(void); #else -static inline void migrate_disable(void) { } -static inline void migrate_enable(void) { } +static inline void migrate_disable(void) +{ + preempt_lazy_disable(); +} + +static inline void migrate_enable(void) +{ + preempt_lazy_enable(); +} #endif /* CONFIG_SMP */ diff --git a/include/linux/printk.h b/include/linux/printk.h index e834d78f0478..c4f127d7fc38 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -47,6 +47,12 @@ static inline const char *printk_skip_headers(const char *buffer) #define CONSOLE_EXT_LOG_MAX 8192 +/* + * The maximum size of a record formatted for console printing + * (i.e. with the prefix prepended to every line). + */ +#define CONSOLE_LOG_MAX 1024 + /* printk's without a loglevel use this.. */ #define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT @@ -150,18 +156,6 @@ static inline __printf(1, 2) __cold void early_printk(const char *s, ...) { } #endif -#ifdef CONFIG_PRINTK_NMI -extern void printk_nmi_enter(void); -extern void printk_nmi_exit(void); -extern void printk_nmi_direct_enter(void); -extern void printk_nmi_direct_exit(void); -#else -static inline void printk_nmi_enter(void) { } -static inline void printk_nmi_exit(void) { } -static inline void printk_nmi_direct_enter(void) { } -static inline void printk_nmi_direct_exit(void) { } -#endif /* PRINTK_NMI */ - struct dev_printk_info; #ifdef CONFIG_PRINTK @@ -176,10 +170,7 @@ int vprintk(const char *fmt, va_list args); asmlinkage __printf(1, 2) __cold int printk(const char *fmt, ...); -/* - * Special printk facility for scheduler/timekeeping use only, _DO_NOT_USE_ ! - */ -__printf(1, 2) __cold int printk_deferred(const char *fmt, ...); +bool pr_flush(int timeout_ms, bool reset_on_progress); /* * Please don't use printk_ratelimit(), because it shares ratelimiting state @@ -209,8 +200,6 @@ void dump_stack_print_info(const char *log_lvl); void show_regs_print_info(const char *log_lvl); extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; extern asmlinkage void dump_stack(void) __cold; -extern void printk_safe_flush(void); -extern void printk_safe_flush_on_panic(void); #else static inline __printf(1, 0) int vprintk(const char *s, va_list args) @@ -222,11 +211,12 @@ int printk(const char *s, ...) { return 0; } -static inline __printf(1, 2) __cold -int printk_deferred(const char *s, ...) + +static inline bool pr_flush(int timeout_ms, bool reset_on_progress) { - return 0; + return true; } + static inline int printk_ratelimit(void) { return 0; @@ -278,31 +268,36 @@ static inline void dump_stack_lvl(const char *log_lvl) static inline void dump_stack(void) { } - -static inline void printk_safe_flush(void) -{ -} - -static inline void printk_safe_flush_on_panic(void) -{ -} #endif #ifdef CONFIG_SMP extern int __printk_cpu_trylock(void); extern void __printk_wait_on_cpu_lock(void); extern void __printk_cpu_unlock(void); +extern bool kgdb_roundup_delay(unsigned int cpu); + +#else + +#define __printk_cpu_trylock() 1 +#define __printk_wait_on_cpu_lock() +#define __printk_cpu_unlock() + +static inline bool kgdb_roundup_delay(unsigned int cpu) +{ + return false; +} +#endif /* CONFIG_SMP */ /** - * printk_cpu_lock_irqsave() - Acquire the printk cpu-reentrant spinning - * lock and disable interrupts. + * raw_printk_cpu_lock_irqsave() - Acquire the printk cpu-reentrant spinning + * lock and disable interrupts. * @flags: Stack-allocated storage for saving local interrupt state, - * to be passed to printk_cpu_unlock_irqrestore(). + * to be passed to raw_printk_cpu_unlock_irqrestore(). * * If the lock is owned by another CPU, spin until it becomes available. * Interrupts are restored while spinning. */ -#define printk_cpu_lock_irqsave(flags) \ +#define raw_printk_cpu_lock_irqsave(flags) \ for (;;) { \ local_irq_save(flags); \ if (__printk_cpu_trylock()) \ @@ -312,22 +307,30 @@ extern void __printk_cpu_unlock(void); } /** - * printk_cpu_unlock_irqrestore() - Release the printk cpu-reentrant spinning - * lock and restore interrupts. - * @flags: Caller's saved interrupt state, from printk_cpu_lock_irqsave(). + * raw_printk_cpu_unlock_irqrestore() - Release the printk cpu-reentrant + * spinning lock and restore interrupts. + * @flags: Caller's saved interrupt state from raw_printk_cpu_lock_irqsave(). */ -#define printk_cpu_unlock_irqrestore(flags) \ +#define raw_printk_cpu_unlock_irqrestore(flags) \ do { \ __printk_cpu_unlock(); \ local_irq_restore(flags); \ - } while (0) \ + } while (0) -#else - -#define printk_cpu_lock_irqsave(flags) ((void)flags) -#define printk_cpu_unlock_irqrestore(flags) ((void)flags) +/* + * Used to synchronize atomic consoles. + * + * The same as raw_printk_cpu_lock_irqsave() except that hardware interrupts + * are _not_ restored while spinning. + */ +#define console_atomic_lock(flags) \ + do { \ + local_irq_save(flags); \ + while (!__printk_cpu_trylock()) \ + cpu_relax(); \ + } while (0) -#endif /* CONFIG_SMP */ +#define console_atomic_unlock raw_printk_cpu_unlock_irqrestore extern int kptr_restrict; @@ -484,13 +487,9 @@ extern int kptr_restrict; #ifdef CONFIG_PRINTK #define printk_once(fmt, ...) \ DO_ONCE_LITE(printk, fmt, ##__VA_ARGS__) -#define printk_deferred_once(fmt, ...) \ - DO_ONCE_LITE(printk_deferred, fmt, ##__VA_ARGS__) #else #define printk_once(fmt, ...) \ no_printk(fmt, ##__VA_ARGS__) -#define printk_deferred_once(fmt, ...) \ - no_printk(fmt, ##__VA_ARGS__) #endif #define pr_emerg_once(fmt, ...) \ diff --git a/include/linux/random.h b/include/linux/random.h index f45b8be3e3c4..0e41d0527809 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -35,7 +35,7 @@ static inline void add_latent_entropy(void) {} extern void add_input_randomness(unsigned int type, unsigned int code, unsigned int value) __latent_entropy; -extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy; +extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) __latent_entropy; extern void get_random_bytes(void *buf, int nbytes); extern int wait_for_random_bytes(void); diff --git a/include/linux/ratelimit_types.h b/include/linux/ratelimit_types.h index b676aa419eef..c21c7f8103e2 100644 --- a/include/linux/ratelimit_types.h +++ b/include/linux/ratelimit_types.h @@ -4,7 +4,7 @@ #include <linux/bits.h> #include <linux/param.h> -#include <linux/spinlock_types.h> +#include <linux/spinlock_types_raw.h> #define DEFAULT_RATELIMIT_INTERVAL (5 * HZ) #define DEFAULT_RATELIMIT_BURST 10 diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h index d31ecaf4fdd3..235047d7a1b5 100644 --- a/include/linux/rbtree.h +++ b/include/linux/rbtree.h @@ -17,24 +17,14 @@ #ifndef _LINUX_RBTREE_H #define _LINUX_RBTREE_H +#include <linux/rbtree_types.h> + #include <linux/kernel.h> #include <linux/stddef.h> #include <linux/rcupdate.h> -struct rb_node { - unsigned long __rb_parent_color; - struct rb_node *rb_right; - struct rb_node *rb_left; -} __attribute__((aligned(sizeof(long)))); - /* The alignment might seem pointless, but allegedly CRIS needs it */ - -struct rb_root { - struct rb_node *rb_node; -}; - #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) -#define RB_ROOT (struct rb_root) { NULL, } #define rb_entry(ptr, type, member) container_of(ptr, type, member) #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL) @@ -112,23 +102,6 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent typeof(*pos), field); 1; }); \ pos = n) -/* - * Leftmost-cached rbtrees. - * - * We do not cache the rightmost node based on footprint - * size vs number of potential users that could benefit - * from O(1) rb_last(). Just not worth it, users that want - * this feature can always implement the logic explicitly. - * Furthermore, users that want to cache both pointers may - * find it a bit asymmetric, but that's ok. - */ -struct rb_root_cached { - struct rb_root rb_root; - struct rb_node *rb_leftmost; -}; - -#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } - /* Same as rb_first(), but O(1) */ #define rb_first_cached(root) (root)->rb_leftmost diff --git a/include/linux/rbtree_types.h b/include/linux/rbtree_types.h new file mode 100644 index 000000000000..45b6ecde3665 --- /dev/null +++ b/include/linux/rbtree_types.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_RBTREE_TYPES_H +#define _LINUX_RBTREE_TYPES_H + +struct rb_node { + unsigned long __rb_parent_color; + struct rb_node *rb_right; + struct rb_node *rb_left; +} __attribute__((aligned(sizeof(long)))); +/* The alignment might seem pointless, but allegedly CRIS needs it */ + +struct rb_root { + struct rb_node *rb_node; +}; + +/* + * Leftmost-cached rbtrees. + * + * We do not cache the rightmost node based on footprint + * size vs number of potential users that could benefit + * from O(1) rb_last(). Just not worth it, users that want + * this feature can always implement the logic explicitly. + * Furthermore, users that want to cache both pointers may + * find it a bit asymmetric, but that's ok. + */ +struct rb_root_cached { + struct rb_root rb_root; + struct rb_node *rb_leftmost; +}; + +#define RB_ROOT (struct rb_root) { NULL, } +#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } + +#endif diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 955c82b4737c..d177cd22bc78 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -54,6 +54,11 @@ void __rcu_read_unlock(void); * types of kernel builds, the rcu_read_lock() nesting depth is unknowable. */ #define rcu_preempt_depth() (current->rcu_read_lock_nesting) +#ifndef CONFIG_PREEMPT_RT +#define sched_rcu_preempt_depth() rcu_preempt_depth() +#else +static inline int sched_rcu_preempt_depth(void) { return 0; } +#endif #else /* #ifdef CONFIG_PREEMPT_RCU */ @@ -79,6 +84,8 @@ static inline int rcu_preempt_depth(void) return 0; } +#define sched_rcu_preempt_depth() rcu_preempt_depth() + #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ /* Internal to kernel */ @@ -94,6 +101,13 @@ void rcu_init_tasks_generic(void); static inline void rcu_init_tasks_generic(void) { } #endif +#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TASKS_RCU_GENERIC) +void rcu_tasks_initiate_self_tests(void); +#else +static inline void rcu_tasks_initiate_self_tests(void) {} +#endif + + #ifdef CONFIG_RCU_STALL_COMMON void rcu_sysrq_start(void); void rcu_sysrq_end(void); diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h index 87b325aec508..7d049883a08a 100644 --- a/include/linux/rtmutex.h +++ b/include/linux/rtmutex.h @@ -13,12 +13,39 @@ #ifndef __LINUX_RT_MUTEX_H #define __LINUX_RT_MUTEX_H +#include <linux/compiler.h> #include <linux/linkage.h> -#include <linux/rbtree.h> -#include <linux/spinlock_types.h> +#include <linux/rbtree_types.h> +#include <linux/spinlock_types_raw.h> extern int max_lock_depth; /* for sysctl */ +struct rt_mutex_base { + raw_spinlock_t wait_lock; + struct rb_root_cached waiters; + struct task_struct *owner; +}; + +#define __RT_MUTEX_BASE_INITIALIZER(rtbasename) \ +{ \ + .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(rtbasename.wait_lock), \ + .waiters = RB_ROOT_CACHED, \ + .owner = NULL \ +} + +/** + * rt_mutex_base_is_locked - is the rtmutex locked + * @lock: the mutex to be queried + * + * Returns true if the mutex is locked, false if unlocked. + */ +static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock) +{ + return READ_ONCE(lock->owner) != NULL; +} + +extern void rt_mutex_base_init(struct rt_mutex_base *rtb); + /** * The rt_mutex structure * @@ -28,9 +55,7 @@ extern int max_lock_depth; /* for sysctl */ * @owner: the mutex owner */ struct rt_mutex { - raw_spinlock_t wait_lock; - struct rb_root_cached waiters; - struct task_struct *owner; + struct rt_mutex_base rtmutex; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif @@ -63,37 +88,33 @@ do { \ #define __RT_MUTEX_INITIALIZER(mutexname) \ { \ - .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock), \ - .waiters = RB_ROOT_CACHED, \ - .owner = NULL, \ + .rtmutex = __RT_MUTEX_BASE_INITIALIZER(mutexname.rtmutex), \ __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \ } #define DEFINE_RT_MUTEX(mutexname) \ struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname) -/** - * rt_mutex_is_locked - is the mutex locked - * @lock: the mutex to be queried - * - * Returns 1 if the mutex is locked, 0 if unlocked. - */ -static inline int rt_mutex_is_locked(struct rt_mutex *lock) -{ - return lock->owner != NULL; -} - extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key); #ifdef CONFIG_DEBUG_LOCK_ALLOC extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass); +extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock); #define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0) +#define rt_mutex_lock_nest_lock(lock, nest_lock) \ + do { \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ + _rt_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \ + } while (0) + #else extern void rt_mutex_lock(struct rt_mutex *lock); #define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock) +#define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock) #endif extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); +extern int rt_mutex_lock_killable(struct rt_mutex *lock); extern int rt_mutex_trylock(struct rt_mutex *lock); extern void rt_mutex_unlock(struct rt_mutex *lock); diff --git a/include/linux/rwbase_rt.h b/include/linux/rwbase_rt.h new file mode 100644 index 000000000000..1d264dd08625 --- /dev/null +++ b/include/linux/rwbase_rt.h @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +#ifndef _LINUX_RWBASE_RT_H +#define _LINUX_RWBASE_RT_H + +#include <linux/rtmutex.h> +#include <linux/atomic.h> + +#define READER_BIAS (1U << 31) +#define WRITER_BIAS (1U << 30) + +struct rwbase_rt { + atomic_t readers; + struct rt_mutex_base rtmutex; +}; + +#define __RWBASE_INITIALIZER(name) \ +{ \ + .readers = ATOMIC_INIT(READER_BIAS), \ + .rtmutex = __RT_MUTEX_BASE_INITIALIZER(name.rtmutex), \ +} + +#define init_rwbase_rt(rwbase) \ + do { \ + rt_mutex_base_init(&(rwbase)->rtmutex); \ + atomic_set(&(rwbase)->readers, READER_BIAS); \ + } while (0) + + +static __always_inline bool rw_base_is_locked(struct rwbase_rt *rwb) +{ + return atomic_read(&rwb->readers) != READER_BIAS; +} + +static __always_inline bool rw_base_is_contended(struct rwbase_rt *rwb) +{ + return atomic_read(&rwb->readers) > 0; +} + +#endif /* _LINUX_RWBASE_RT_H */ diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h new file mode 100644 index 000000000000..49c1f3842ed5 --- /dev/null +++ b/include/linux/rwlock_rt.h @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-only +#ifndef __LINUX_RWLOCK_RT_H +#define __LINUX_RWLOCK_RT_H + +#ifndef __LINUX_SPINLOCK_RT_H +#error Do not #include directly. Use <linux/spinlock.h>. +#endif + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern void __rt_rwlock_init(rwlock_t *rwlock, const char *name, + struct lock_class_key *key); +#else +static inline void __rt_rwlock_init(rwlock_t *rwlock, char *name, + struct lock_class_key *key) +{ +} +#endif + +#define rwlock_init(rwl) \ +do { \ + static struct lock_class_key __key; \ + \ + init_rwbase_rt(&(rwl)->rwbase); \ + __rt_rwlock_init(rwl, #rwl, &__key); \ +} while (0) + +extern void rt_read_lock(rwlock_t *rwlock); +extern int rt_read_trylock(rwlock_t *rwlock); +extern void rt_read_unlock(rwlock_t *rwlock); +extern void rt_write_lock(rwlock_t *rwlock); +extern int rt_write_trylock(rwlock_t *rwlock); +extern void rt_write_unlock(rwlock_t *rwlock); + +static __always_inline void read_lock(rwlock_t *rwlock) +{ + rt_read_lock(rwlock); +} + +static __always_inline void read_lock_bh(rwlock_t *rwlock) +{ + local_bh_disable(); + rt_read_lock(rwlock); +} + +static __always_inline void read_lock_irq(rwlock_t *rwlock) +{ + rt_read_lock(rwlock); +} + +#define read_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + rt_read_lock(lock); \ + flags = 0; \ + } while (0) + +#define read_trylock(lock) __cond_lock(lock, rt_read_trylock(lock)) + +static __always_inline void read_unlock(rwlock_t *rwlock) +{ + rt_read_unlock(rwlock); +} + +static __always_inline void read_unlock_bh(rwlock_t *rwlock) +{ + rt_read_unlock(rwlock); + local_bh_enable(); +} + +static __always_inline void read_unlock_irq(rwlock_t *rwlock) +{ + rt_read_unlock(rwlock); +} + +static __always_inline void read_unlock_irqrestore(rwlock_t *rwlock, + unsigned long flags) +{ + rt_read_unlock(rwlock); +} + +static __always_inline void write_lock(rwlock_t *rwlock) +{ + rt_write_lock(rwlock); +} + +static __always_inline void write_lock_bh(rwlock_t *rwlock) +{ + local_bh_disable(); + rt_write_lock(rwlock); +} + +static __always_inline void write_lock_irq(rwlock_t *rwlock) +{ + rt_write_lock(rwlock); +} + +#define write_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + rt_write_lock(lock); \ + flags = 0; \ + } while (0) + +#define write_trylock(lock) __cond_lock(lock, rt_write_trylock(lock)) + +#define write_trylock_irqsave(lock, flags) \ +({ \ + int __locked; \ + \ + typecheck(unsigned long, flags); \ + flags = 0; \ + __locked = write_trylock(lock); \ + __locked; \ +}) + +static __always_inline void write_unlock(rwlock_t *rwlock) +{ + rt_write_unlock(rwlock); +} + +static __always_inline void write_unlock_bh(rwlock_t *rwlock) +{ + rt_write_unlock(rwlock); + local_bh_enable(); +} + +static __always_inline void write_unlock_irq(rwlock_t *rwlock) +{ + rt_write_unlock(rwlock); +} + +static __always_inline void write_unlock_irqrestore(rwlock_t *rwlock, + unsigned long flags) +{ + rt_write_unlock(rwlock); +} + +#define rwlock_is_contended(lock) (((void)(lock), 0)) + +#endif /* __LINUX_RWLOCK_RT_H */ diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h index 3bd03e18061c..1948442e7750 100644 --- a/include/linux/rwlock_types.h +++ b/include/linux/rwlock_types.h @@ -1,9 +1,23 @@ #ifndef __LINUX_RWLOCK_TYPES_H #define __LINUX_RWLOCK_TYPES_H +#if !defined(__LINUX_SPINLOCK_TYPES_H) +# error "Do not include directly, include spinlock_types.h" +#endif + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define RW_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_CONFIG, \ + } +#else +# define RW_DEP_MAP_INIT(lockname) +#endif + +#ifndef CONFIG_PREEMPT_RT /* - * include/linux/rwlock_types.h - generic rwlock type definitions - * and initializers + * generic rwlock type definitions and initializers * * portions Copyright 2005, Red Hat, Inc., Ingo Molnar * Released under the General Public License (GPL). @@ -21,16 +35,6 @@ typedef struct { #define RWLOCK_MAGIC 0xdeaf1eed -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define RW_DEP_MAP_INIT(lockname) \ - .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_CONFIG, \ - } -#else -# define RW_DEP_MAP_INIT(lockname) -#endif - #ifdef CONFIG_DEBUG_SPINLOCK #define __RW_LOCK_UNLOCKED(lockname) \ (rwlock_t) { .raw_lock = __ARCH_RW_LOCK_UNLOCKED, \ @@ -46,4 +50,29 @@ typedef struct { #define DEFINE_RWLOCK(x) rwlock_t x = __RW_LOCK_UNLOCKED(x) +#else /* !CONFIG_PREEMPT_RT */ + +#include <linux/rwbase_rt.h> + +typedef struct { + struct rwbase_rt rwbase; + atomic_t readers; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +} rwlock_t; + +#define __RWLOCK_RT_INITIALIZER(name) \ +{ \ + .rwbase = __RWBASE_INITIALIZER(name), \ + RW_DEP_MAP_INIT(name) \ +} + +#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name) + +#define DEFINE_RWLOCK(name) \ + rwlock_t name = __RW_LOCK_UNLOCKED(name) + +#endif /* CONFIG_PREEMPT_RT */ + #endif /* __LINUX_RWLOCK_TYPES_H */ diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index a66038d88878..426e98e0b675 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -16,6 +16,19 @@ #include <linux/spinlock.h> #include <linux/atomic.h> #include <linux/err.h> + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define __RWSEM_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_SLEEP, \ + }, +#else +# define __RWSEM_DEP_MAP_INIT(lockname) +#endif + +#ifndef CONFIG_PREEMPT_RT + #ifdef CONFIG_RWSEM_SPIN_ON_OWNER #include <linux/osq_lock.h> #endif @@ -64,16 +77,6 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) /* Common initializer macros and functions */ -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define __RWSEM_DEP_MAP_INIT(lockname) \ - .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_SLEEP, \ - }, -#else -# define __RWSEM_DEP_MAP_INIT(lockname) -#endif - #ifdef CONFIG_DEBUG_RWSEMS # define __RWSEM_DEBUG_INIT(lockname) .magic = &lockname, #else @@ -119,6 +122,61 @@ static inline int rwsem_is_contended(struct rw_semaphore *sem) return !list_empty(&sem->wait_list); } +#else /* !CONFIG_PREEMPT_RT */ + +#include <linux/rwbase_rt.h> + +struct rw_semaphore { + struct rwbase_rt rwbase; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +}; + +#define __RWSEM_INITIALIZER(name) \ + { \ + .rwbase = __RWBASE_INITIALIZER(name), \ + __RWSEM_DEP_MAP_INIT(name) \ + } + +#define DECLARE_RWSEM(lockname) \ + struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname) + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern void __rwsem_init(struct rw_semaphore *rwsem, const char *name, + struct lock_class_key *key); +#else +static inline void __rwsem_init(struct rw_semaphore *rwsem, const char *name, + struct lock_class_key *key) +{ +} +#endif + +#define init_rwsem(sem) \ +do { \ + static struct lock_class_key __key; \ + \ + init_rwbase_rt(&(sem)->rwbase); \ + __rwsem_init((sem), #sem, &__key); \ +} while (0) + +static __always_inline int rwsem_is_locked(struct rw_semaphore *sem) +{ + return rw_base_is_locked(&sem->rwbase); +} + +static __always_inline int rwsem_is_contended(struct rw_semaphore *sem) +{ + return rw_base_is_contended(&sem->rwbase); +} + +#endif /* CONFIG_PREEMPT_RT */ + +/* + * The functions below are the same for all rwsem implementations including + * the RT specific variant. + */ + /* * lock for reading */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 8e10c7accdbc..9188f416de0b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -95,7 +95,9 @@ struct task_group; #define TASK_WAKING 0x0200 #define TASK_NOLOAD 0x0400 #define TASK_NEW 0x0800 -#define TASK_STATE_MAX 0x1000 +/* RT specific auxilliary flag to mark RT lock waiters */ +#define TASK_RTLOCK_WAIT 0x1000 +#define TASK_STATE_MAX 0x2000 /* Convenience macros for the sake of set_current_state: */ #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE) @@ -115,14 +117,8 @@ struct task_group; #define task_is_running(task) (READ_ONCE((task)->__state) == TASK_RUNNING) -#define task_is_traced(task) ((READ_ONCE(task->__state) & __TASK_TRACED) != 0) - #define task_is_stopped(task) ((READ_ONCE(task->__state) & __TASK_STOPPED) != 0) -#define task_is_stopped_or_traced(task) ((READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED)) != 0) - -#ifdef CONFIG_DEBUG_ATOMIC_SLEEP - /* * Special states are those that do not use the normal wait-loop pattern. See * the comment with set_special_state(). @@ -130,30 +126,37 @@ struct task_group; #define is_special_task_state(state) \ ((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED | TASK_DEAD)) -#define __set_current_state(state_value) \ - do { \ - WARN_ON_ONCE(is_special_task_state(state_value));\ - current->task_state_change = _THIS_IP_; \ - WRITE_ONCE(current->__state, (state_value)); \ - } while (0) - -#define set_current_state(state_value) \ - do { \ - WARN_ON_ONCE(is_special_task_state(state_value));\ - current->task_state_change = _THIS_IP_; \ - smp_store_mb(current->__state, (state_value)); \ +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP +# define debug_normal_state_change(state_value) \ + do { \ + WARN_ON_ONCE(is_special_task_state(state_value)); \ + current->task_state_change = _THIS_IP_; \ } while (0) -#define set_special_state(state_value) \ +# define debug_special_state_change(state_value) \ do { \ - unsigned long flags; /* may shadow */ \ WARN_ON_ONCE(!is_special_task_state(state_value)); \ - raw_spin_lock_irqsave(¤t->pi_lock, flags); \ current->task_state_change = _THIS_IP_; \ - WRITE_ONCE(current->__state, (state_value)); \ - raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ } while (0) + +# define debug_rtlock_wait_set_state() \ + do { \ + current->saved_state_change = current->task_state_change;\ + current->task_state_change = _THIS_IP_; \ + } while (0) + +# define debug_rtlock_wait_restore_state() \ + do { \ + current->task_state_change = current->saved_state_change;\ + } while (0) + #else +# define debug_normal_state_change(cond) do { } while (0) +# define debug_special_state_change(cond) do { } while (0) +# define debug_rtlock_wait_set_state() do { } while (0) +# define debug_rtlock_wait_restore_state() do { } while (0) +#endif + /* * set_current_state() includes a barrier so that the write of current->state * is correctly serialised wrt the caller's subsequent test of whether to @@ -192,26 +195,77 @@ struct task_group; * Also see the comments of try_to_wake_up(). */ #define __set_current_state(state_value) \ - WRITE_ONCE(current->__state, (state_value)) + do { \ + debug_normal_state_change((state_value)); \ + WRITE_ONCE(current->__state, (state_value)); \ + } while (0) #define set_current_state(state_value) \ - smp_store_mb(current->__state, (state_value)) + do { \ + debug_normal_state_change((state_value)); \ + smp_store_mb(current->__state, (state_value)); \ + } while (0) /* * set_special_state() should be used for those states when the blocking task * can not use the regular condition based wait-loop. In that case we must - * serialize against wakeups such that any possible in-flight TASK_RUNNING stores - * will not collide with our state change. + * serialize against wakeups such that any possible in-flight TASK_RUNNING + * stores will not collide with our state change. */ #define set_special_state(state_value) \ do { \ unsigned long flags; /* may shadow */ \ + \ raw_spin_lock_irqsave(¤t->pi_lock, flags); \ + debug_special_state_change((state_value)); \ WRITE_ONCE(current->__state, (state_value)); \ raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ } while (0) -#endif +/* + * PREEMPT_RT specific variants for "sleeping" spin/rwlocks + * + * RT's spin/rwlock substitutions are state preserving. The state of the + * task when blocking on the lock is saved in task_struct::saved_state and + * restored after the lock has been acquired. These operations are + * serialized by task_struct::pi_lock against try_to_wake_up(). Any non RT + * lock related wakeups while the task is blocked on the lock are + * redirected to operate on task_struct::saved_state to ensure that these + * are not dropped. On restore task_struct::saved_state is set to + * TASK_RUNNING so any wakeup attempt redirected to saved_state will fail. + * + * The lock operation looks like this: + * + * current_save_and_set_rtlock_wait_state(); + * for (;;) { + * if (try_lock()) + * break; + * raw_spin_unlock_irq(&lock->wait_lock); + * schedule_rtlock(); + * raw_spin_lock_irq(&lock->wait_lock); + * set_current_state(TASK_RTLOCK_WAIT); + * } + * current_restore_rtlock_saved_state(); + */ +#define current_save_and_set_rtlock_wait_state() \ + do { \ + lockdep_assert_irqs_disabled(); \ + raw_spin_lock(¤t->pi_lock); \ + current->saved_state = current->__state; \ + debug_rtlock_wait_set_state(); \ + WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT); \ + raw_spin_unlock(¤t->pi_lock); \ + } while (0); + +#define current_restore_rtlock_saved_state() \ + do { \ + lockdep_assert_irqs_disabled(); \ + raw_spin_lock(¤t->pi_lock); \ + debug_rtlock_wait_restore_state(); \ + WRITE_ONCE(current->__state, current->saved_state); \ + current->saved_state = TASK_RUNNING; \ + raw_spin_unlock(¤t->pi_lock); \ + } while (0); #define get_current_state() READ_ONCE(current->__state) @@ -230,6 +284,9 @@ extern long schedule_timeout_idle(long timeout); asmlinkage void schedule(void); extern void schedule_preempt_disabled(void); asmlinkage void preempt_schedule_irq(void); +#ifdef CONFIG_PREEMPT_RT + extern void schedule_rtlock(void); +#endif extern int __must_check io_schedule_prepare(void); extern void io_schedule_finish(int token); @@ -668,6 +725,11 @@ struct task_struct { #endif unsigned int __state; +#ifdef CONFIG_PREEMPT_RT + /* saved state for "spinlock sleepers" */ + unsigned int saved_state; +#endif + /* * This begins the randomizable portion of task_struct. Only * scheduling-critical items should be added above here. @@ -863,6 +925,10 @@ struct task_struct { /* Used by page_owner=on to detect recursion in page tracking. */ unsigned in_page_owner:1; #endif +#ifdef CONFIG_EVENTFD + /* Recursion prevention for eventfd_signal() */ + unsigned in_eventfd_signal:1; +#endif unsigned long atomic_flags; /* Flags requiring atomic access. */ @@ -1012,6 +1078,10 @@ struct task_struct { /* Restored if set_restore_sigmask() was used: */ sigset_t saved_sigmask; struct sigpending pending; +#ifdef CONFIG_PREEMPT_RT + /* TODO: move me into ->restart_block ? */ + struct kernel_siginfo forced_info; +#endif unsigned long sas_ss_sp; size_t sas_ss_size; unsigned int sas_ss_flags; @@ -1357,6 +1427,9 @@ struct task_struct { struct kmap_ctrl kmap_ctrl; #ifdef CONFIG_DEBUG_ATOMIC_SLEEP unsigned long task_state_change; +# ifdef CONFIG_PREEMPT_RT + unsigned long saved_state_change; +# endif #endif int pagefault_disabled; #ifdef CONFIG_MMU @@ -1643,6 +1716,16 @@ static __always_inline bool is_percpu_thread(void) #endif } +/* Is the current task guaranteed to stay on its current CPU? */ +static inline bool is_migratable(void) +{ +#ifdef CONFIG_SMP + return preemptible() && !current->migration_disabled; +#else + return false; +#endif +} + /* Per-process atomic flags. */ #define PFA_NO_NEW_PRIVS 0 /* May not gain new privileges. */ #define PFA_SPREAD_PAGE 1 /* Spread page cache over cpuset */ @@ -1898,6 +1981,118 @@ static inline int test_tsk_need_resched(struct task_struct *tsk) return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED)); } +#ifdef CONFIG_PREEMPT_LAZY +static inline void set_tsk_need_resched_lazy(struct task_struct *tsk) +{ + set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY); +} + +static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) +{ + clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY); +} + +static inline int test_tsk_need_resched_lazy(struct task_struct *tsk) +{ + return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY)); +} + +static inline int need_resched_lazy(void) +{ + return test_thread_flag(TIF_NEED_RESCHED_LAZY); +} + +static inline int need_resched_now(void) +{ + return test_thread_flag(TIF_NEED_RESCHED); +} + +#else +static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { } +static inline int need_resched_lazy(void) { return 0; } + +static inline int need_resched_now(void) +{ + return test_thread_flag(TIF_NEED_RESCHED); +} + +#endif + +#ifdef CONFIG_PREEMPT_RT +static inline bool task_match_saved_state(struct task_struct *p, long match_state) +{ + return p->saved_state == match_state; +} + +static inline bool task_is_traced(struct task_struct *task) +{ + bool traced = false; + + /* in case the task is sleeping on tasklist_lock */ + raw_spin_lock_irq(&task->pi_lock); + if (READ_ONCE(task->__state) & __TASK_TRACED) + traced = true; + else if (task->saved_state & __TASK_TRACED) + traced = true; + raw_spin_unlock_irq(&task->pi_lock); + return traced; +} + +static inline bool task_is_stopped_or_traced(struct task_struct *task) +{ + bool traced_stopped = false; + unsigned long flags; + + raw_spin_lock_irqsave(&task->pi_lock, flags); + + if (READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED)) + traced_stopped = true; + else if (task->saved_state & (__TASK_STOPPED | __TASK_TRACED)) + traced_stopped = true; + + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + return traced_stopped; +} + +#else + +static inline bool task_match_saved_state(struct task_struct *p, long match_state) +{ + return false; +} + +static inline bool task_is_traced(struct task_struct *task) +{ + return READ_ONCE(task->__state) & __TASK_TRACED; +} + +static inline bool task_is_stopped_or_traced(struct task_struct *task) +{ + return READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED); +} +#endif + +static inline bool task_match_state_or_saved(struct task_struct *p, + long match_state) +{ + if (READ_ONCE(p->__state) == match_state) + return true; + + return task_match_saved_state(p, match_state); +} + +static inline bool task_match_state_lock(struct task_struct *p, + long match_state) +{ + bool match; + + raw_spin_lock_irq(&p->pi_lock); + match = task_match_state_or_saved(p, match_state); + raw_spin_unlock_irq(&p->pi_lock); + + return match; +} + /* * cond_resched() and cond_resched_lock(): latency reduction via * explicit rescheduling in places that are safe. The return diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index e24b1fe348e3..52ecb2c11c18 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -49,6 +49,17 @@ static inline void mmdrop(struct mm_struct *mm) __mmdrop(mm); } +#ifdef CONFIG_PREEMPT_RT +extern void __mmdrop_delayed(struct rcu_head *rhp); +static inline void mmdrop_delayed(struct mm_struct *mm) +{ + if (atomic_dec_and_test(&mm->mm_count)) + call_rcu(&mm->delayed_drop, __mmdrop_delayed); +} +#else +# define mmdrop_delayed(mm) mmdrop(mm) +#endif + /** * mmget() - Pin the address space associated with a &struct mm_struct. * @mm: The address space to pin. diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h index 26a2013ac39c..06cd8fb2f409 100644 --- a/include/linux/sched/wake_q.h +++ b/include/linux/sched/wake_q.h @@ -42,8 +42,11 @@ struct wake_q_head { #define WAKE_Q_TAIL ((struct wake_q_node *) 0x01) -#define DEFINE_WAKE_Q(name) \ - struct wake_q_head name = { WAKE_Q_TAIL, &name.first } +#define WAKE_Q_HEAD_INITIALIZER(name) \ + { WAKE_Q_TAIL, &name.first } + +#define DEFINE_WAKE_Q(name) \ + struct wake_q_head name = WAKE_Q_HEAD_INITIALIZER(name) static inline void wake_q_init(struct wake_q_head *head) { diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 5db211f43b29..aa011f668705 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -7,6 +7,7 @@ #ifndef _LINUX_SERIAL_8250_H #define _LINUX_SERIAL_8250_H +#include <linux/atomic.h> #include <linux/serial_core.h> #include <linux/serial_reg.h> #include <linux/platform_device.h> @@ -125,6 +126,8 @@ struct uart_8250_port { #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA unsigned char msr_saved_flags; + atomic_t console_printing; + struct uart_8250_dma *dma; const struct uart_8250_ops *ops; @@ -180,6 +183,8 @@ void serial8250_init_port(struct uart_8250_port *up); void serial8250_set_defaults(struct uart_8250_port *up); void serial8250_console_write(struct uart_8250_port *up, const char *s, unsigned int count); +void serial8250_console_write_atomic(struct uart_8250_port *up, const char *s, + unsigned int count); int serial8250_console_setup(struct uart_port *port, char *options, bool probe); int serial8250_console_exit(struct uart_port *port); diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 8e775ce517bb..0a8499fb9c3c 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -31,7 +31,7 @@ struct shmem_sb_info { struct percpu_counter used_blocks; /* How many are allocated */ unsigned long max_inodes; /* How many inodes are allowed */ unsigned long free_inodes; /* How many are left for allocation */ - spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ + raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ umode_t mode; /* Mount mode for root directory */ unsigned char huge; /* Whether to try for hugepages */ kuid_t uid; /* Mount uid for root directory */ diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 4f7478c48273..351a1b5075f1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -297,6 +297,7 @@ struct sk_buff_head { __u32 qlen; spinlock_t lock; + raw_spinlock_t raw_lock; }; struct sk_buff; @@ -1911,6 +1912,12 @@ static inline void skb_queue_head_init(struct sk_buff_head *list) __skb_queue_head_init(list); } +static inline void skb_queue_head_init_raw(struct sk_buff_head *list) +{ + raw_spin_lock_init(&list->raw_lock); + __skb_queue_head_init(list); +} + static inline void skb_queue_head_init_class(struct sk_buff_head *list, struct lock_class_key *class) { diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index dcde82a4434c..85499f0586b0 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -10,6 +10,7 @@ #include <linux/kfence.h> #include <linux/kobject.h> #include <linux/reciprocal_div.h> +#include <linux/local_lock.h> enum stat_item { ALLOC_FASTPATH, /* Allocation from cpu slab */ @@ -40,6 +41,10 @@ enum stat_item { CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */ NR_SLUB_STAT_ITEMS }; +/* + * When changing the layout, make sure freelist and tid are still compatible + * with this_cpu_cmpxchg_double() alignment requirements. + */ struct kmem_cache_cpu { void **freelist; /* Pointer to next available object */ unsigned long tid; /* Globally unique transaction id */ @@ -47,6 +52,7 @@ struct kmem_cache_cpu { #ifdef CONFIG_SLUB_CPU_PARTIAL struct page *partial; /* Partially allocated frozen slabs */ #endif + local_lock_t lock; /* Protects the fields above */ #ifdef CONFIG_SLUB_STATS unsigned stat[NR_SLUB_STAT_ITEMS]; #endif diff --git a/include/linux/smp.h b/include/linux/smp.h index 510519e8a1eb..7ac9fdb5ad09 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -268,6 +268,9 @@ static inline int get_boot_cpu_id(void) #define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) #define put_cpu() preempt_enable() +#define get_cpu_light() ({ migrate_disable(); __smp_processor_id(); }) +#define put_cpu_light() migrate_enable() + /* * Callback to arch code if there's nosmp or maxcpus=0 on the * boot command line: diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 79897841a2cc..45310ea1b1d7 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -12,6 +12,8 @@ * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the * initializers * + * linux/spinlock_types_raw: + * The raw types and initializers * linux/spinlock_types.h: * defines the generic type and initializers * @@ -31,6 +33,8 @@ * contains the generic, simplified UP spinlock type. * (which is an empty structure on non-debug builds) * + * linux/spinlock_types_raw: + * The raw RT types and initializers * linux/spinlock_types.h: * defines the generic type and initializers * @@ -308,8 +312,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) 1 : ({ local_irq_restore(flags); 0; }); \ }) -/* Include rwlock functions */ +#ifndef CONFIG_PREEMPT_RT +/* Include rwlock functions for !RT */ #include <linux/rwlock.h> +#endif /* * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: @@ -320,6 +326,9 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) # include <linux/spinlock_api_up.h> #endif +/* Non PREEMPT_RT kernel, map to raw spinlocks: */ +#ifndef CONFIG_PREEMPT_RT + /* * Map the spin_lock functions to the raw variants for PREEMPT_RT=n */ @@ -454,6 +463,10 @@ static __always_inline int spin_is_contended(spinlock_t *lock) #define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) +#else /* !CONFIG_PREEMPT_RT */ +# include <linux/spinlock_rt.h> +#endif /* CONFIG_PREEMPT_RT */ + /* * Pull the atomic_t declaration: * (asm-mips/atomic.h needs above definitions) diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h index 19a9be9d97ee..6b8e1a0b137b 100644 --- a/include/linux/spinlock_api_smp.h +++ b/include/linux/spinlock_api_smp.h @@ -187,6 +187,9 @@ static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock) return 0; } +/* PREEMPT_RT has its own rwlock implementation */ +#ifndef CONFIG_PREEMPT_RT #include <linux/rwlock_api_smp.h> +#endif #endif /* __LINUX_SPINLOCK_API_SMP_H */ diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h new file mode 100644 index 000000000000..835aedaf68ac --- /dev/null +++ b/include/linux/spinlock_rt.h @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0-only +#ifndef __LINUX_SPINLOCK_RT_H +#define __LINUX_SPINLOCK_RT_H + +#ifndef __LINUX_SPINLOCK_H +#error Do not include directly. Use spinlock.h +#endif + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern void __rt_spin_lock_init(spinlock_t *lock, const char *name, + struct lock_class_key *key, bool percpu); +#else +static inline void __rt_spin_lock_init(spinlock_t *lock, const char *name, + struct lock_class_key *key, bool percpu) +{ +} +#endif + +#define spin_lock_init(slock) \ +do { \ + static struct lock_class_key __key; \ + \ + rt_mutex_base_init(&(slock)->lock); \ + __rt_spin_lock_init(slock, #slock, &__key, false); \ +} while (0) + +#define local_spin_lock_init(slock) \ +do { \ + static struct lock_class_key __key; \ + \ + rt_mutex_base_init(&(slock)->lock); \ + __rt_spin_lock_init(slock, #slock, &__key, true); \ +} while (0) + +extern void rt_spin_lock(spinlock_t *lock); +extern void rt_spin_lock_nested(spinlock_t *lock, int subclass); +extern void rt_spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *nest_lock); +extern void rt_spin_unlock(spinlock_t *lock); +extern void rt_spin_lock_unlock(spinlock_t *lock); +extern int rt_spin_trylock_bh(spinlock_t *lock); +extern int rt_spin_trylock(spinlock_t *lock); + +static __always_inline void spin_lock(spinlock_t *lock) +{ + rt_spin_lock(lock); +} + +#ifdef CONFIG_LOCKDEP +# define __spin_lock_nested(lock, subclass) \ + rt_spin_lock_nested(lock, subclass) + +# define __spin_lock_nest_lock(lock, nest_lock) \ + do { \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \ + rt_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ + } while (0) +# define __spin_lock_irqsave_nested(lock, flags, subclass) \ + do { \ + typecheck(unsigned long, flags); \ + flags = 0; \ + __spin_lock_nested(lock, subclass); \ + } while (0) + +#else + /* + * Always evaluate the 'subclass' argument to avoid that the compiler + * warns about set-but-not-used variables when building with + * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. + */ +# define __spin_lock_nested(lock, subclass) spin_lock(((void)(subclass), (lock))) +# define __spin_lock_nest_lock(lock, subclass) spin_lock(((void)(subclass), (lock))) +# define __spin_lock_irqsave_nested(lock, flags, subclass) \ + spin_lock_irqsave(((void)(subclass), (lock)), flags) +#endif + +#define spin_lock_nested(lock, subclass) \ + __spin_lock_nested(lock, subclass) + +#define spin_lock_nest_lock(lock, nest_lock) \ + __spin_lock_nest_lock(lock, nest_lock) + +#define spin_lock_irqsave_nested(lock, flags, subclass) \ + __spin_lock_irqsave_nested(lock, flags, subclass) + +static __always_inline void spin_lock_bh(spinlock_t *lock) +{ + /* Investigate: Drop bh when blocking ? */ + local_bh_disable(); + rt_spin_lock(lock); +} + +static __always_inline void spin_lock_irq(spinlock_t *lock) +{ + rt_spin_lock(lock); +} + +#define spin_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + flags = 0; \ + spin_lock(lock); \ + } while (0) + +static __always_inline void spin_unlock(spinlock_t *lock) +{ + rt_spin_unlock(lock); +} + +static __always_inline void spin_unlock_bh(spinlock_t *lock) +{ + rt_spin_unlock(lock); + local_bh_enable(); +} + +static __always_inline void spin_unlock_irq(spinlock_t *lock) +{ + rt_spin_unlock(lock); +} + +static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, + unsigned long flags) +{ + rt_spin_unlock(lock); +} + +#define spin_trylock(lock) \ + __cond_lock(lock, rt_spin_trylock(lock)) + +#define spin_trylock_bh(lock) \ + __cond_lock(lock, rt_spin_trylock_bh(lock)) + +#define spin_trylock_irq(lock) \ + __cond_lock(lock, rt_spin_trylock(lock)) + +#define __spin_trylock_irqsave(lock, flags) \ +({ \ + int __locked; \ + \ + typecheck(unsigned long, flags); \ + flags = 0; \ + __locked = spin_trylock(lock); \ + __locked; \ +}) + +#define spin_trylock_irqsave(lock, flags) \ + __cond_lock(lock, __spin_trylock_irqsave(lock, flags)) + +#define spin_is_contended(lock) (((void)(lock), 0)) + +static inline int spin_is_locked(spinlock_t *lock) +{ + return rt_mutex_base_is_locked(&lock->lock); +} + +#define assert_spin_locked(lock) BUG_ON(!spin_is_locked(lock)) + +#include <linux/rwlock_rt.h> + +#endif diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h index b981caafe8bf..2dfa35ffec76 100644 --- a/include/linux/spinlock_types.h +++ b/include/linux/spinlock_types.h @@ -9,65 +9,11 @@ * Released under the General Public License (GPL). */ -#if defined(CONFIG_SMP) -# include <asm/spinlock_types.h> -#else -# include <linux/spinlock_types_up.h> -#endif - -#include <linux/lockdep_types.h> +#include <linux/spinlock_types_raw.h> -typedef struct raw_spinlock { - arch_spinlock_t raw_lock; -#ifdef CONFIG_DEBUG_SPINLOCK - unsigned int magic, owner_cpu; - void *owner; -#endif -#ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map dep_map; -#endif -} raw_spinlock_t; - -#define SPINLOCK_MAGIC 0xdead4ead - -#define SPINLOCK_OWNER_INIT ((void *)-1L) - -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define RAW_SPIN_DEP_MAP_INIT(lockname) \ - .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_SPIN, \ - } -# define SPIN_DEP_MAP_INIT(lockname) \ - .dep_map = { \ - .name = #lockname, \ - .wait_type_inner = LD_WAIT_CONFIG, \ - } -#else -# define RAW_SPIN_DEP_MAP_INIT(lockname) -# define SPIN_DEP_MAP_INIT(lockname) -#endif - -#ifdef CONFIG_DEBUG_SPINLOCK -# define SPIN_DEBUG_INIT(lockname) \ - .magic = SPINLOCK_MAGIC, \ - .owner_cpu = -1, \ - .owner = SPINLOCK_OWNER_INIT, -#else -# define SPIN_DEBUG_INIT(lockname) -#endif - -#define __RAW_SPIN_LOCK_INITIALIZER(lockname) \ - { \ - .raw_lock = __ARCH_SPIN_LOCK_UNLOCKED, \ - SPIN_DEBUG_INIT(lockname) \ - RAW_SPIN_DEP_MAP_INIT(lockname) } - -#define __RAW_SPIN_LOCK_UNLOCKED(lockname) \ - (raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname) - -#define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) +#ifndef CONFIG_PREEMPT_RT +/* Non PREEMPT_RT kernels map spinlock to raw_spinlock */ typedef struct spinlock { union { struct raw_spinlock rlock; @@ -96,6 +42,35 @@ typedef struct spinlock { #define DEFINE_SPINLOCK(x) spinlock_t x = __SPIN_LOCK_UNLOCKED(x) +#else /* !CONFIG_PREEMPT_RT */ + +/* PREEMPT_RT kernels map spinlock to rt_mutex */ +#include <linux/rtmutex.h> + +typedef struct spinlock { + struct rt_mutex_base lock; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +} spinlock_t; + +#define __SPIN_LOCK_UNLOCKED(name) \ + { \ + .lock = __RT_MUTEX_BASE_INITIALIZER(name.lock), \ + SPIN_DEP_MAP_INIT(name) \ + } + +#define __LOCAL_SPIN_LOCK_UNLOCKED(name) \ + { \ + .lock = __RT_MUTEX_BASE_INITIALIZER(name.lock), \ + LOCAL_SPIN_DEP_MAP_INIT(name) \ + } + +#define DEFINE_SPINLOCK(name) \ + spinlock_t name = __SPIN_LOCK_UNLOCKED(name) + +#endif /* CONFIG_PREEMPT_RT */ + #include <linux/rwlock_types.h> #endif /* __LINUX_SPINLOCK_TYPES_H */ diff --git a/include/linux/spinlock_types_raw.h b/include/linux/spinlock_types_raw.h new file mode 100644 index 000000000000..91cb36b65a17 --- /dev/null +++ b/include/linux/spinlock_types_raw.h @@ -0,0 +1,73 @@ +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H +#define __LINUX_SPINLOCK_TYPES_RAW_H + +#include <linux/types.h> + +#if defined(CONFIG_SMP) +# include <asm/spinlock_types.h> +#else +# include <linux/spinlock_types_up.h> +#endif + +#include <linux/lockdep_types.h> + +typedef struct raw_spinlock { + arch_spinlock_t raw_lock; +#ifdef CONFIG_DEBUG_SPINLOCK + unsigned int magic, owner_cpu; + void *owner; +#endif +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif +} raw_spinlock_t; + +#define SPINLOCK_MAGIC 0xdead4ead + +#define SPINLOCK_OWNER_INIT ((void *)-1L) + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define RAW_SPIN_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_SPIN, \ + } +# define SPIN_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_CONFIG, \ + } + +# define LOCAL_SPIN_DEP_MAP_INIT(lockname) \ + .dep_map = { \ + .name = #lockname, \ + .wait_type_inner = LD_WAIT_CONFIG, \ + .lock_type = LD_LOCK_PERCPU, \ + } +#else +# define RAW_SPIN_DEP_MAP_INIT(lockname) +# define SPIN_DEP_MAP_INIT(lockname) +# define LOCAL_SPIN_DEP_MAP_INIT(lockname) +#endif + +#ifdef CONFIG_DEBUG_SPINLOCK +# define SPIN_DEBUG_INIT(lockname) \ + .magic = SPINLOCK_MAGIC, \ + .owner_cpu = -1, \ + .owner = SPINLOCK_OWNER_INIT, +#else +# define SPIN_DEBUG_INIT(lockname) +#endif + +#define __RAW_SPIN_LOCK_INITIALIZER(lockname) \ +{ \ + .raw_lock = __ARCH_SPIN_LOCK_UNLOCKED, \ + SPIN_DEBUG_INIT(lockname) \ + RAW_SPIN_DEP_MAP_INIT(lockname) } + +#define __RAW_SPIN_LOCK_UNLOCKED(lockname) \ + (raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname) + +#define DEFINE_RAW_SPINLOCK(x) raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x) + +#endif /* __LINUX_SPINLOCK_TYPES_RAW_H */ diff --git a/include/linux/spinlock_types_up.h b/include/linux/spinlock_types_up.h index c09b6407ae1b..7f86a2016ac5 100644 --- a/include/linux/spinlock_types_up.h +++ b/include/linux/spinlock_types_up.h @@ -1,7 +1,7 @@ #ifndef __LINUX_SPINLOCK_TYPES_UP_H #define __LINUX_SPINLOCK_TYPES_UP_H -#ifndef __LINUX_SPINLOCK_TYPES_H +#ifndef __LINUX_SPINLOCK_TYPES_RAW_H # error "please don't include this file directly" #endif diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 8af13ba60c7e..79b6933ef8a0 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -550,23 +550,17 @@ static inline void unlock_system_sleep(void) {} #ifdef CONFIG_PM_SLEEP_DEBUG extern bool pm_print_times_enabled; extern bool pm_debug_messages_on; -extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...); +extern __printf(1, 2) void pm_pr_dbg(const char *fmt, ...); #else #define pm_print_times_enabled (false) #define pm_debug_messages_on (false) #include <linux/printk.h> -#define __pm_pr_dbg(defer, fmt, ...) \ +#define pm_pr_dbg(fmt, ...) \ no_printk(KERN_DEBUG fmt, ##__VA_ARGS__) #endif -#define pm_pr_dbg(fmt, ...) \ - __pm_pr_dbg(false, fmt, ##__VA_ARGS__) - -#define pm_deferred_pr_dbg(fmt, ...) \ - __pm_pr_dbg(true, fmt, ##__VA_ARGS__) - #ifdef CONFIG_PM_AUTOSLEEP /* kernel/power/autosleep.c */ diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 0999f6317978..7af834b7c114 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -163,7 +163,17 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag) clear_ti_thread_flag(task_thread_info(t), TIF_##fl) #endif /* !CONFIG_GENERIC_ENTRY */ -#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED) +#ifdef CONFIG_PREEMPT_LAZY +#define tif_need_resched() (test_thread_flag(TIF_NEED_RESCHED) || \ + test_thread_flag(TIF_NEED_RESCHED_LAZY)) +#define tif_need_resched_now() (test_thread_flag(TIF_NEED_RESCHED)) +#define tif_need_resched_lazy() test_thread_flag(TIF_NEED_RESCHED_LAZY) + +#else +#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED) +#define tif_need_resched_now() test_thread_flag(TIF_NEED_RESCHED) +#define tif_need_resched_lazy() 0 +#endif #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES static inline int arch_within_stack_frames(const void * const stack, diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index ad413b382a3c..415fb02dd13f 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -69,6 +69,8 @@ struct trace_entry { unsigned char flags; unsigned char preempt_count; int pid; + unsigned char migrate_disable; + unsigned char preempt_lazy_count; }; #define TRACE_EVENT_TYPE_MAX \ @@ -157,9 +159,11 @@ static inline void tracing_generic_entry_update(struct trace_entry *entry, unsigned int trace_ctx) { entry->preempt_count = trace_ctx & 0xff; + entry->migrate_disable = (trace_ctx >> 8) & 0xff; + entry->preempt_lazy_count = (trace_ctx >> 16) & 0xff; entry->pid = current->pid; entry->type = type; - entry->flags = trace_ctx >> 16; + entry->flags = trace_ctx >> 24; } unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status); @@ -172,6 +176,7 @@ enum trace_flag_type { TRACE_FLAG_SOFTIRQ = 0x10, TRACE_FLAG_PREEMPT_RESCHED = 0x20, TRACE_FLAG_NMI = 0x40, + TRACE_FLAG_NEED_RESCHED_LAZY = 0x80, }; #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h index e81856c0ba13..66eb968a09d4 100644 --- a/include/linux/u64_stats_sync.h +++ b/include/linux/u64_stats_sync.h @@ -66,7 +66,7 @@ #include <linux/seqlock.h> struct u64_stats_sync { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG==32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) seqcount_t seq; #endif }; @@ -115,7 +115,7 @@ static inline void u64_stats_inc(u64_stats_t *p) } #endif -#if BITS_PER_LONG == 32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) #define u64_stats_init(syncp) seqcount_init(&(syncp)->seq) #else static inline void u64_stats_init(struct u64_stats_sync *syncp) @@ -125,15 +125,19 @@ static inline void u64_stats_init(struct u64_stats_sync *syncp) static inline void u64_stats_update_begin(struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); write_seqcount_begin(&syncp->seq); #endif } static inline void u64_stats_update_end(struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) write_seqcount_end(&syncp->seq); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); #endif } @@ -142,8 +146,11 @@ u64_stats_update_begin_irqsave(struct u64_stats_sync *syncp) { unsigned long flags = 0; -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - local_irq_save(flags); +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + else + local_irq_save(flags); write_seqcount_begin(&syncp->seq); #endif return flags; @@ -153,15 +160,18 @@ static inline void u64_stats_update_end_irqrestore(struct u64_stats_sync *syncp, unsigned long flags) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) write_seqcount_end(&syncp->seq); - local_irq_restore(flags); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); + else + local_irq_restore(flags); #endif } static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) return read_seqcount_begin(&syncp->seq); #else return 0; @@ -170,7 +180,7 @@ static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync * static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT)) preempt_disable(); #endif return __u64_stats_fetch_begin(syncp); @@ -179,7 +189,7 @@ static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *sy static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp, unsigned int start) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)) return read_seqcount_retry(&syncp->seq, start); #else return false; @@ -189,7 +199,7 @@ static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp, static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp, unsigned int start) { -#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT)) preempt_enable(); #endif return __u64_stats_fetch_retry(syncp, start); @@ -203,7 +213,9 @@ static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp, */ static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT) + preempt_disable(); +#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP) local_irq_disable(); #endif return __u64_stats_fetch_begin(syncp); @@ -212,7 +224,9 @@ static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync *syncp, unsigned int start) { -#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) +#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT) + preempt_enable(); +#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP) local_irq_enable(); #endif return __u64_stats_fetch_retry(syncp, start); diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index d6a6cf53b127..81f001e71a31 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -63,7 +63,9 @@ DECLARE_PER_CPU(struct vm_event_state, vm_event_states); */ static inline void __count_vm_event(enum vm_event_item item) { + preempt_disable_rt(); raw_cpu_inc(vm_event_states.event[item]); + preempt_enable_rt(); } static inline void count_vm_event(enum vm_event_item item) @@ -73,7 +75,9 @@ static inline void count_vm_event(enum vm_event_item item) static inline void __count_vm_events(enum vm_event_item item, long delta) { + preempt_disable_rt(); raw_cpu_add(vm_event_states.event[item], delta); + preempt_enable_rt(); } static inline void count_vm_events(enum vm_event_item item, long delta) diff --git a/include/linux/wait.h b/include/linux/wait.h index 6598ae35e1b5..172efca327e9 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -10,6 +10,7 @@ #include <asm/current.h> #include <uapi/linux/wait.h> +#include <linux/atomic.h> typedef struct wait_queue_entry wait_queue_entry_t; diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h index b77f39f319ad..29db736af86d 100644 --- a/include/linux/ww_mutex.h +++ b/include/linux/ww_mutex.h @@ -18,6 +18,24 @@ #define __LINUX_WW_MUTEX_H #include <linux/mutex.h> +#include <linux/rtmutex.h> + +#if defined(CONFIG_DEBUG_MUTEXES) || \ + (defined(CONFIG_PREEMPT_RT) && defined(CONFIG_DEBUG_RT_MUTEXES)) +#define DEBUG_WW_MUTEXES +#endif + +#ifndef CONFIG_PREEMPT_RT +#define WW_MUTEX_BASE mutex +#define ww_mutex_base_init(l,n,k) __mutex_init(l,n,k) +#define ww_mutex_base_trylock(l) mutex_trylock(l) +#define ww_mutex_base_is_locked(b) mutex_is_locked((b)) +#else +#define WW_MUTEX_BASE rt_mutex +#define ww_mutex_base_init(l,n,k) __rt_mutex_init(l,n,k) +#define ww_mutex_base_trylock(l) rt_mutex_trylock(l) +#define ww_mutex_base_is_locked(b) rt_mutex_base_is_locked(&(b)->rtmutex) +#endif struct ww_class { atomic_long_t stamp; @@ -28,16 +46,24 @@ struct ww_class { unsigned int is_wait_die; }; +struct ww_mutex { + struct WW_MUTEX_BASE base; + struct ww_acquire_ctx *ctx; +#ifdef DEBUG_WW_MUTEXES + struct ww_class *ww_class; +#endif +}; + struct ww_acquire_ctx { struct task_struct *task; unsigned long stamp; unsigned int acquired; unsigned short wounded; unsigned short is_wait_die; -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES unsigned int done_acquire; struct ww_class *ww_class; - struct ww_mutex *contending_lock; + void *contending_lock; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; @@ -74,9 +100,9 @@ struct ww_acquire_ctx { static inline void ww_mutex_init(struct ww_mutex *lock, struct ww_class *ww_class) { - __mutex_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key); + ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key); lock->ctx = NULL; -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES lock->ww_class = ww_class; #endif } @@ -113,7 +139,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx, ctx->acquired = 0; ctx->wounded = false; ctx->is_wait_die = ww_class->is_wait_die; -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES ctx->ww_class = ww_class; ctx->done_acquire = 0; ctx->contending_lock = NULL; @@ -143,7 +169,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx, */ static inline void ww_acquire_done(struct ww_acquire_ctx *ctx) { -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES lockdep_assert_held(ctx); DEBUG_LOCKS_WARN_ON(ctx->done_acquire); @@ -163,7 +189,7 @@ static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx) #ifdef CONFIG_DEBUG_LOCK_ALLOC mutex_release(&ctx->dep_map, _THIS_IP_); #endif -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES DEBUG_LOCKS_WARN_ON(ctx->acquired); if (!IS_ENABLED(CONFIG_PROVE_LOCKING)) /* @@ -269,7 +295,7 @@ static inline void ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { int ret; -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES DEBUG_LOCKS_WARN_ON(!ctx->contending_lock); #endif ret = ww_mutex_lock(lock, ctx); @@ -305,7 +331,7 @@ static inline int __must_check ww_mutex_lock_slow_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES DEBUG_LOCKS_WARN_ON(!ctx->contending_lock); #endif return ww_mutex_lock_interruptible(lock, ctx); @@ -322,7 +348,7 @@ extern void ww_mutex_unlock(struct ww_mutex *lock); */ static inline int __must_check ww_mutex_trylock(struct ww_mutex *lock) { - return mutex_trylock(&lock->base); + return ww_mutex_base_trylock(&lock->base); } /*** @@ -335,7 +361,9 @@ static inline int __must_check ww_mutex_trylock(struct ww_mutex *lock) */ static inline void ww_mutex_destroy(struct ww_mutex *lock) { +#ifndef CONFIG_PREEMPT_RT mutex_destroy(&lock->base); +#endif } /** @@ -346,7 +374,7 @@ static inline void ww_mutex_destroy(struct ww_mutex *lock) */ static inline bool ww_mutex_is_locked(struct ww_mutex *lock) { - return mutex_is_locked(&lock->base); + return ww_mutex_base_is_locked(&lock->base); } #endif diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h index 1424e02cef90..163f8415e5db 100644 --- a/include/net/gen_stats.h +++ b/include/net/gen_stats.h @@ -6,6 +6,7 @@ #include <linux/socket.h> #include <linux/rtnetlink.h> #include <linux/pkt_sched.h> +#include <net/net_seq_lock.h> /* Note: this used to be in include/uapi/linux/gen_stats.h */ struct gnet_stats_basic_packed { @@ -42,15 +43,15 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type, spinlock_t *lock, struct gnet_dump *d, int padattr); -int gnet_stats_copy_basic(const seqcount_t *running, +int gnet_stats_copy_basic(net_seqlock_t *running, struct gnet_dump *d, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b); -void __gnet_stats_copy_basic(const seqcount_t *running, +void __gnet_stats_copy_basic(net_seqlock_t *running, struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b); -int gnet_stats_copy_basic_hw(const seqcount_t *running, +int gnet_stats_copy_basic_hw(net_seqlock_t *running, struct gnet_dump *d, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b); @@ -70,13 +71,13 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu_bstats, struct net_rate_estimator __rcu **rate_est, spinlock_t *lock, - seqcount_t *running, struct nlattr *opt); + net_seqlock_t *running, struct nlattr *opt); void gen_kill_estimator(struct net_rate_estimator __rcu **ptr); int gen_replace_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu_bstats, struct net_rate_estimator __rcu **ptr, spinlock_t *lock, - seqcount_t *running, struct nlattr *opt); + net_seqlock_t *running, struct nlattr *opt); bool gen_estimator_active(struct net_rate_estimator __rcu **ptr); bool gen_estimator_read(struct net_rate_estimator __rcu **ptr, struct gnet_stats_rate_est64 *sample); diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h new file mode 100644 index 000000000000..67710bace741 --- /dev/null +++ b/include/net/net_seq_lock.h @@ -0,0 +1,15 @@ +#ifndef __NET_NET_SEQ_LOCK_H__ +#define __NET_NET_SEQ_LOCK_H__ + +#ifdef CONFIG_PREEMPT_RT +# define net_seqlock_t seqlock_t +# define net_seq_begin(__r) read_seqbegin(__r) +# define net_seq_retry(__r, __s) read_seqretry(__r, __s) + +#else +# define net_seqlock_t seqcount_t +# define net_seq_begin(__r) read_seqcount_begin(__r) +# define net_seq_retry(__r, __s) read_seqcount_retry(__r, __s) +#endif + +#endif diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 30da65a421d7..c25c01e2faca 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -10,6 +10,7 @@ #include <linux/percpu.h> #include <linux/dynamic_queue_limits.h> #include <linux/list.h> +#include <net/net_seq_lock.h> #include <linux/refcount.h> #include <linux/workqueue.h> #include <linux/mutex.h> @@ -108,7 +109,7 @@ struct Qdisc { struct sk_buff_head gso_skb ____cacheline_aligned_in_smp; struct qdisc_skb_head q; struct gnet_stats_basic_packed bstats; - seqcount_t running; + net_seqlock_t running; struct gnet_stats_queue qstats; unsigned long state; struct Qdisc *next_sched; @@ -147,7 +148,11 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc) { if (qdisc->flags & TCQ_F_NOLOCK) return spin_is_locked(&qdisc->seqlock); +#ifdef CONFIG_PREEMPT_RT + return spin_is_locked(&qdisc->running.lock); +#else return (raw_read_seqcount(&qdisc->running) & 1) ? true : false; +#endif } static inline bool nolock_qdisc_is_empty(const struct Qdisc *qdisc) @@ -209,12 +214,28 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) } else if (qdisc_is_running(qdisc)) { return false; } + +#ifdef CONFIG_PREEMPT_RT + if (spin_trylock(&qdisc->running.lock)) { + seqcount_t *s = &qdisc->running.seqcount.seqcount; + + /* + * Variant of write_seqcount_t_begin() telling lockdep that + * a trylock was attempted. + */ + do_raw_write_seqcount_begin(s); + seqcount_acquire(&s->dep_map, 0, 1, _RET_IP_); + return true; + } + return false; +#else /* Variant of write_seqcount_begin() telling lockdep a trylock * was attempted. */ raw_write_seqcount_begin(&qdisc->running); seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_); return true; +#endif } static inline void qdisc_run_end(struct Qdisc *qdisc) @@ -226,7 +247,11 @@ static inline void qdisc_run_end(struct Qdisc *qdisc) &qdisc->state))) __netif_schedule(qdisc); } else { +#ifdef CONFIG_PREEMPT_RT + write_sequnlock(&qdisc->running); +#else write_seqcount_end(&qdisc->running); +#endif } } @@ -592,7 +617,7 @@ static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc) return qdisc_lock(root); } -static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc) +static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc) { struct Qdisc *root = qdisc_root_sleeping(qdisc); diff --git a/init/Kconfig b/init/Kconfig index 55f9f7738ebb..bb0703889a03 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -910,6 +910,7 @@ config PAGE_COUNTER config MEMCG bool "Memory controller" + depends on !PREEMPT_RT select PAGE_COUNTER select EVENTFD help @@ -980,6 +981,7 @@ config CFS_BANDWIDTH config RT_GROUP_SCHED bool "Group scheduling for SCHED_RR/FIFO" depends on CGROUP_SCHED + depends on !PREEMPT_RT default n help This feature lets you explicitly allocate real CPU bandwidth @@ -1509,11 +1511,6 @@ config PRINTK very difficult to diagnose system problems, saying N here is strongly discouraged. -config PRINTK_NMI - def_bool y - depends on PRINTK - depends on HAVE_NMI - config BUG bool "BUG() support" if EXPERT default y @@ -1873,6 +1870,7 @@ choice config SLAB bool "SLAB" + depends on !PREEMPT_RT select HAVE_HARDENED_USERCOPY_ALLOCATOR help The regular slab allocator that is established and known to work @@ -1893,6 +1891,7 @@ config SLUB config SLOB depends on EXPERT bool "SLOB (Simple Allocator)" + depends on !PREEMPT_RT help SLOB replaces the stock allocator with a drastically simpler allocator. SLOB is generally more space efficient but diff --git a/init/main.c b/init/main.c index 70fed1294617..768555301065 100644 --- a/init/main.c +++ b/init/main.c @@ -1598,6 +1598,7 @@ static noinline void __init kernel_init_freeable(void) rcu_init_tasks_generic(); do_pre_smp_initcalls(); + rcu_tasks_initiate_self_tests(); lockup_detector_init(); smp_init(); diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index 3de8fd11873b..4198f0273ecd 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -251,7 +251,7 @@ config ARCH_USE_QUEUED_RWLOCKS config QUEUED_RWLOCKS def_bool y if ARCH_USE_QUEUED_RWLOCKS - depends on SMP + depends on SMP && !PREEMPT_RT config ARCH_HAS_MMIOWB bool diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index 5876e30c5740..5df0776264c2 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -1,5 +1,11 @@ # SPDX-License-Identifier: GPL-2.0-only +config HAVE_PREEMPT_LAZY + bool + +config PREEMPT_LAZY + def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT + choice prompt "Preemption Model" default PREEMPT_NONE diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 13b5be6df4da..c7f82b3f5ec5 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -345,7 +345,7 @@ void cpuset_read_unlock(void) percpu_up_read(&cpuset_rwsem); } -static DEFINE_SPINLOCK(callback_lock); +static DEFINE_RAW_SPINLOCK(callback_lock); static struct workqueue_struct *cpuset_migrate_mm_wq; @@ -1282,7 +1282,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, * Newly added CPUs will be removed from effective_cpus and * newly deleted ones will be added back to effective_cpus. */ - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); if (adding) { cpumask_or(parent->subparts_cpus, parent->subparts_cpus, tmp->addmask); @@ -1304,7 +1304,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, if (cpuset->partition_root_state != new_prs) cpuset->partition_root_state = new_prs; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); return cmd == partcmd_update; } @@ -1407,7 +1407,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) continue; rcu_read_unlock(); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cpumask_copy(cp->effective_cpus, tmp->new_cpus); if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) { @@ -1441,7 +1441,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) if (new_prs != cp->partition_root_state) cp->partition_root_state = new_prs; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); WARN_ON(!is_in_v2_mode() && !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); @@ -1559,7 +1559,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, return -EINVAL; } - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); /* @@ -1570,7 +1570,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, cs->cpus_allowed); cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus); } - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); update_cpumasks_hier(cs, &tmp); @@ -1764,9 +1764,9 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) continue; rcu_read_unlock(); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cp->effective_mems = *new_mems; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems)); @@ -1834,9 +1834,9 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, if (retval < 0) goto done; - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->mems_allowed = trialcs->mems_allowed; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); /* use trialcs->mems_allowed as a temp variable */ update_nodemasks_hier(cs, &trialcs->mems_allowed); @@ -1927,9 +1927,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) || (is_spread_page(cs) != is_spread_page(trialcs))); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->flags = trialcs->flags; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) rebuild_sched_domains_locked(); @@ -2020,9 +2020,9 @@ static int update_prstate(struct cpuset *cs, int new_prs) rebuild_sched_domains_locked(); out: if (!err) { - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->partition_root_state = new_prs; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); } free_cpumasks(NULL, &tmpmask); @@ -2438,7 +2438,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v) cpuset_filetype_t type = seq_cft(sf)->private; int ret = 0; - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); switch (type) { case FILE_CPULIST: @@ -2460,7 +2460,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v) ret = -EINVAL; } - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); return ret; } @@ -2773,14 +2773,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) cpuset_inc(); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); if (is_in_v2_mode()) { cpumask_copy(cs->effective_cpus, parent->effective_cpus); cs->effective_mems = parent->effective_mems; cs->use_parent_ecpus = true; parent->child_ecpus_count++; } - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) goto out_unlock; @@ -2807,12 +2807,12 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) } rcu_read_unlock(); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->mems_allowed = parent->mems_allowed; cs->effective_mems = parent->mems_allowed; cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); cpumask_copy(cs->effective_cpus, parent->cpus_allowed); - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); out_unlock: percpu_up_write(&cpuset_rwsem); put_online_cpus(); @@ -2868,7 +2868,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css) static void cpuset_bind(struct cgroup_subsys_state *root_css) { percpu_down_write(&cpuset_rwsem); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); if (is_in_v2_mode()) { cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); @@ -2879,7 +2879,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) top_cpuset.mems_allowed = top_cpuset.effective_mems; } - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); percpu_up_write(&cpuset_rwsem); } @@ -2976,12 +2976,12 @@ hotplug_update_tasks_legacy(struct cpuset *cs, { bool is_empty; - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cpumask_copy(cs->cpus_allowed, new_cpus); cpumask_copy(cs->effective_cpus, new_cpus); cs->mems_allowed = *new_mems; cs->effective_mems = *new_mems; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); /* * Don't call update_tasks_cpumask() if the cpuset becomes empty, @@ -3018,10 +3018,10 @@ hotplug_update_tasks(struct cpuset *cs, if (nodes_empty(*new_mems)) *new_mems = parent_cs(cs)->effective_mems; - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cpumask_copy(cs->effective_cpus, new_cpus); cs->effective_mems = *new_mems; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); if (cpus_updated) update_tasks_cpumask(cs); @@ -3088,10 +3088,10 @@ retry: if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || (parent->partition_root_state == PRS_ERROR))) { if (cs->nr_subparts_cpus) { - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->nr_subparts_cpus = 0; cpumask_clear(cs->subparts_cpus); - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); compute_effective_cpumask(&new_cpus, cs, parent); } @@ -3105,9 +3105,9 @@ retry: cpumask_empty(&new_cpus)) { update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp); - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); cs->partition_root_state = PRS_ERROR; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); } cpuset_force_rebuild(); } @@ -3187,7 +3187,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); if (!on_dfl) cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); /* @@ -3207,17 +3207,17 @@ static void cpuset_hotplug_workfn(struct work_struct *work) } } cpumask_copy(top_cpuset.effective_cpus, &new_cpus); - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); /* we don't mess with cpumasks of tasks in top_cpuset */ } /* synchronize mems_allowed to N_MEMORY */ if (mems_updated) { - spin_lock_irq(&callback_lock); + raw_spin_lock_irq(&callback_lock); if (!on_dfl) top_cpuset.mems_allowed = new_mems; top_cpuset.effective_mems = new_mems; - spin_unlock_irq(&callback_lock); + raw_spin_unlock_irq(&callback_lock); update_tasks_nodemask(&top_cpuset); } @@ -3318,11 +3318,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) { unsigned long flags; - spin_lock_irqsave(&callback_lock, flags); + raw_spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); guarantee_online_cpus(task_cs(tsk), pmask); rcu_read_unlock(); - spin_unlock_irqrestore(&callback_lock, flags); + raw_spin_unlock_irqrestore(&callback_lock, flags); } /** @@ -3383,11 +3383,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) nodemask_t mask; unsigned long flags; - spin_lock_irqsave(&callback_lock, flags); + raw_spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); guarantee_online_mems(task_cs(tsk), &mask); rcu_read_unlock(); - spin_unlock_irqrestore(&callback_lock, flags); + raw_spin_unlock_irqrestore(&callback_lock, flags); return mask; } @@ -3479,14 +3479,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) return true; /* Not hardwall and node outside mems_allowed: scan up cpusets */ - spin_lock_irqsave(&callback_lock, flags); + raw_spin_lock_irqsave(&callback_lock, flags); rcu_read_lock(); cs = nearest_hardwall_ancestor(task_cs(current)); allowed = node_isset(node, cs->mems_allowed); rcu_read_unlock(); - spin_unlock_irqrestore(&callback_lock, flags); + raw_spin_unlock_irqrestore(&callback_lock, flags); return allowed; } diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 1486768f2318..bb3b805436c4 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -156,8 +156,9 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep) raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu); struct cgroup *pos = NULL; + unsigned long flags; - raw_spin_lock(cpu_lock); + raw_spin_lock_irqsave(cpu_lock, flags); while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) { struct cgroup_subsys_state *css; @@ -169,7 +170,7 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep) css->ss->css_rstat_flush(css, cpu); rcu_read_unlock(); } - raw_spin_unlock(cpu_lock); + raw_spin_unlock_irqrestore(cpu_lock, flags); /* if @may_sleep, play nice and yield if necessary */ if (may_sleep && (need_resched() || diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index b4aa6bb6b2bd..9117ca86b81c 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -241,35 +241,42 @@ NOKPROBE_SYMBOL(kgdb_call_nmi_hook); static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd) = CSD_INIT(kgdb_call_nmi_hook, NULL); -void __weak kgdb_roundup_cpus(void) +void __weak kgdb_roundup_cpu(unsigned int cpu) { call_single_data_t *csd; + int ret; + + csd = &per_cpu(kgdb_roundup_csd, cpu); + + /* + * If it didn't round up last time, don't try again + * since smp_call_function_single_async() will block. + * + * If rounding_up is false then we know that the + * previous call must have at least started and that + * means smp_call_function_single_async() won't block. + */ + if (kgdb_info[cpu].rounding_up) + return; + kgdb_info[cpu].rounding_up = true; + + ret = smp_call_function_single_async(cpu, csd); + if (ret) + kgdb_info[cpu].rounding_up = false; +} +NOKPROBE_SYMBOL(kgdb_roundup_cpu); + +void __weak kgdb_roundup_cpus(void) +{ int this_cpu = raw_smp_processor_id(); int cpu; - int ret; for_each_online_cpu(cpu) { /* No need to roundup ourselves */ if (cpu == this_cpu) continue; - csd = &per_cpu(kgdb_roundup_csd, cpu); - - /* - * If it didn't round up last time, don't try again - * since smp_call_function_single_async() will block. - * - * If rounding_up is false then we know that the - * previous call must have at least started and that - * means smp_call_function_single_async() won't block. - */ - if (kgdb_info[cpu].rounding_up) - continue; - kgdb_info[cpu].rounding_up = true; - - ret = smp_call_function_single_async(cpu, csd); - if (ret) - kgdb_info[cpu].rounding_up = false; + kgdb_roundup_cpu(cpu); } } NOKPROBE_SYMBOL(kgdb_roundup_cpus); diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 6735ac36b718..539a2f0dc89d 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -559,23 +559,17 @@ static void kdb_msg_write(const char *msg, int msg_len) cp++; } + /* mirror output on atomic consoles */ for_each_console(c) { if (!(c->flags & CON_ENABLED)) continue; if (c == dbg_io_ops->cons) continue; - /* - * Set oops_in_progress to encourage the console drivers to - * disregard their internal spin locks: in the current calling - * context the risk of deadlock is a bigger problem than risks - * due to re-entering the console driver. We operate directly on - * oops_in_progress rather than using bust_spinlocks() because - * the calls bust_spinlocks() makes on exit are not appropriate - * for this calling context. - */ - ++oops_in_progress; - c->write(c, msg, msg_len); - --oops_in_progress; + + if (!c->write_atomic) + continue; + c->write_atomic(c, msg, msg_len); + touch_nmi_watchdog(); } } diff --git a/kernel/entry/common.c b/kernel/entry/common.c index bf16395b9e13..d8bedab935b2 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -159,9 +159,17 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, local_irq_enable_exit_to_user(ti_work); - if (ti_work & _TIF_NEED_RESCHED) + if (ti_work & _TIF_NEED_RESCHED_MASK) schedule(); +#ifdef ARCH_RT_DELAYS_SIGNAL_SEND + if (unlikely(current->forced_info.si_signo)) { + struct task_struct *t = current; + force_sig_info(&t->forced_info); + t->forced_info.si_signo = 0; + } +#endif + if (ti_work & _TIF_UPROBE) uprobe_notify_resume(regs); @@ -389,7 +397,7 @@ void irqentry_exit_cond_resched(void) rcu_irq_exit_check_preempt(); if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) WARN_ON_ONCE(!on_thread_stack()); - if (need_resched()) + if (should_resched(0)) preempt_schedule_irq(); } } diff --git a/kernel/fork.c b/kernel/fork.c index edfa199270d3..e05fa0fdd25e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -42,6 +42,7 @@ #include <linux/mmu_notifier.h> #include <linux/fs.h> #include <linux/mm.h> +#include <linux/kprobes.h> #include <linux/vmacache.h> #include <linux/nsproxy.h> #include <linux/capability.h> @@ -289,7 +290,7 @@ static inline void free_thread_stack(struct task_struct *tsk) return; } - vfree_atomic(tsk->stack); + vfree(tsk->stack); return; } #endif @@ -693,6 +694,19 @@ void __mmdrop(struct mm_struct *mm) } EXPORT_SYMBOL_GPL(__mmdrop); +#ifdef CONFIG_PREEMPT_RT +/* + * RCU callback for delayed mm drop. Not strictly rcu, but we don't + * want another facility to make this work. + */ +void __mmdrop_delayed(struct rcu_head *rhp) +{ + struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop); + + __mmdrop(mm); +} +#endif + static void mmdrop_async_fn(struct work_struct *work) { struct mm_struct *mm; @@ -734,6 +748,15 @@ void __put_task_struct(struct task_struct *tsk) WARN_ON(refcount_read(&tsk->usage)); WARN_ON(tsk == current); + /* + * Remove function-return probe instances associated with this + * task and put them back on the free list. + */ + kprobe_flush_task(tsk); + + /* Task is done with its stack. */ + put_task_stack(tsk); + io_uring_free(tsk); cgroup_free(tsk); task_numa_free(tsk, true); diff --git a/kernel/futex.c b/kernel/futex.c index 2ecb07575055..a316dce74c3d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -179,7 +179,7 @@ struct futex_pi_state { /* * The PI object: */ - struct rt_mutex pi_mutex; + struct rt_mutex_base pi_mutex; struct task_struct *owner; refcount_t refcount; @@ -197,6 +197,8 @@ struct futex_pi_state { * @rt_waiter: rt_waiter storage for use with requeue_pi * @requeue_pi_key: the requeue_pi target futex key * @bitset: bitset for the optional bitmasked wakeup + * @requeue_state: State field for futex_requeue_pi() + * @requeue_wait: RCU wait for futex_requeue_pi() (RT only) * * We use this hashed waitqueue, instead of a normal wait_queue_entry_t, so * we can wake only the relevant ones (hashed queues may be shared). @@ -219,12 +221,68 @@ struct futex_q { struct rt_mutex_waiter *rt_waiter; union futex_key *requeue_pi_key; u32 bitset; + atomic_t requeue_state; +#ifdef CONFIG_PREEMPT_RT + struct rcuwait requeue_wait; +#endif } __randomize_layout; +/* + * On PREEMPT_RT, the hash bucket lock is a 'sleeping' spinlock with an + * underlying rtmutex. The task which is about to be requeued could have + * just woken up (timeout, signal). After the wake up the task has to + * acquire hash bucket lock, which is held by the requeue code. As a task + * can only be blocked on _ONE_ rtmutex at a time, the proxy lock blocking + * and the hash bucket lock blocking would collide and corrupt state. + * + * On !PREEMPT_RT this is not a problem and everything could be serialized + * on hash bucket lock, but aside of having the benefit of common code, + * this allows to avoid doing the requeue when the task is already on the + * way out and taking the hash bucket lock of the original uaddr1 when the + * requeue has been completed. + * + * The following state transitions are valid: + * + * On the waiter side: + * Q_REQUEUE_PI_NONE -> Q_REQUEUE_PI_IGNORE + * Q_REQUEUE_PI_IN_PROGRESS -> Q_REQUEUE_PI_WAIT + * + * On the requeue side: + * Q_REQUEUE_PI_NONE -> Q_REQUEUE_PI_INPROGRESS + * Q_REQUEUE_PI_IN_PROGRESS -> Q_REQUEUE_PI_DONE/LOCKED + * Q_REQUEUE_PI_IN_PROGRESS -> Q_REQUEUE_PI_NONE (requeue failed) + * Q_REQUEUE_PI_WAIT -> Q_REQUEUE_PI_DONE/LOCKED + * Q_REQUEUE_PI_WAIT -> Q_REQUEUE_PI_IGNORE (requeue failed) + * + * The requeue side ignores a waiter with state Q_REQUEUE_PI_IGNORE as this + * signals that the waiter is already on the way out. It also means that + * the waiter is still on the 'wait' futex, i.e. uaddr1. + * + * The waiter side signals early wakeup to the requeue side either through + * setting state to Q_REQUEUE_PI_IGNORE or to Q_REQUEUE_PI_WAIT depending + * on the current state. In case of Q_REQUEUE_PI_IGNORE it can immediately + * proceed to take the hash bucket lock of uaddr1. If it set state to WAIT, + * which means the wakeup is interleaving with a requeue in progress it has + * to wait for the requeue side to change the state. Either to DONE/LOCKED + * or to IGNORE. DONE/LOCKED means the waiter q is now on the uaddr2 futex + * and either blocked (DONE) or has acquired it (LOCKED). IGNORE is set by + * the requeue side when the requeue attempt failed via deadlock detection + * and therefore the waiter q is still on the uaddr1 futex. + */ +enum { + Q_REQUEUE_PI_NONE = 0, + Q_REQUEUE_PI_IGNORE, + Q_REQUEUE_PI_IN_PROGRESS, + Q_REQUEUE_PI_WAIT, + Q_REQUEUE_PI_DONE, + Q_REQUEUE_PI_LOCKED, +}; + static const struct futex_q futex_q_init = { /* list gets initialized in queue_me()*/ - .key = FUTEX_KEY_INIT, - .bitset = FUTEX_BITSET_MATCH_ANY + .key = FUTEX_KEY_INIT, + .bitset = FUTEX_BITSET_MATCH_ANY, + .requeue_state = ATOMIC_INIT(Q_REQUEUE_PI_NONE), }; /* @@ -1205,6 +1263,36 @@ static int handle_exit_race(u32 __user *uaddr, u32 uval, return -ESRCH; } +static void __attach_to_pi_owner(struct task_struct *p, union futex_key *key, + struct futex_pi_state **ps) +{ + /* + * No existing pi state. First waiter. [2] + * + * This creates pi_state, we have hb->lock held, this means nothing can + * observe this state, wait_lock is irrelevant. + */ + struct futex_pi_state *pi_state = alloc_pi_state(); + + /* + * Initialize the pi_mutex in locked state and make @p + * the owner of it: + */ + rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p); + + /* Store the key for possible exit cleanups: */ + pi_state->key = *key; + + WARN_ON(!list_empty(&pi_state->list)); + list_add(&pi_state->list, &p->pi_state_list); + /* + * Assignment without holding pi_state->pi_mutex.wait_lock is safe + * because there is no concurrency as the object is not published yet. + */ + pi_state->owner = p; + + *ps = pi_state; +} /* * Lookup the task for the TID provided from user space and attach to * it after doing proper sanity checks. @@ -1214,7 +1302,6 @@ static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key, struct task_struct **exiting) { pid_t pid = uval & FUTEX_TID_MASK; - struct futex_pi_state *pi_state; struct task_struct *p; /* @@ -1266,60 +1353,14 @@ static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key, return ret; } - /* - * No existing pi state. First waiter. [2] - * - * This creates pi_state, we have hb->lock held, this means nothing can - * observe this state, wait_lock is irrelevant. - */ - pi_state = alloc_pi_state(); - - /* - * Initialize the pi_mutex in locked state and make @p - * the owner of it: - */ - rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p); - - /* Store the key for possible exit cleanups: */ - pi_state->key = *key; - - WARN_ON(!list_empty(&pi_state->list)); - list_add(&pi_state->list, &p->pi_state_list); - /* - * Assignment without holding pi_state->pi_mutex.wait_lock is safe - * because there is no concurrency as the object is not published yet. - */ - pi_state->owner = p; + __attach_to_pi_owner(p, key, ps); raw_spin_unlock_irq(&p->pi_lock); put_task_struct(p); - *ps = pi_state; - return 0; } -static int lookup_pi_state(u32 __user *uaddr, u32 uval, - struct futex_hash_bucket *hb, - union futex_key *key, struct futex_pi_state **ps, - struct task_struct **exiting) -{ - struct futex_q *top_waiter = futex_top_waiter(hb, key); - - /* - * If there is a waiter on that futex, validate it and - * attach to the pi_state when the validation succeeds. - */ - if (top_waiter) - return attach_to_pi_state(uaddr, uval, top_waiter->pi_state, ps); - - /* - * We are the first waiter - try to look up the owner based on - * @uval and attach to it. - */ - return attach_to_pi_owner(uaddr, uval, key, ps, exiting); -} - static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval) { int err; @@ -1354,7 +1395,7 @@ static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval) * - 1 - acquired the lock; * - <0 - error * - * The hb->lock and futex_key refs shall be held by the caller. + * The hb->lock must be held by the caller. * * @exiting is only set when the return value is -EBUSY. If so, this holds * a refcount on the exiting task on return and the caller needs to drop it @@ -1417,8 +1458,26 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, newval |= FUTEX_WAITERS; ret = lock_pi_update_atomic(uaddr, uval, newval); - /* If the take over worked, return 1 */ - return ret < 0 ? ret : 1; + if (ret) + return ret; + + /* + * If the waiter bit was requested the caller also needs PI + * state attached to the new owner of the user space futex. + * + * @task is guaranteed to be alive and it cannot be exiting + * because it is either sleeping or waiting in + * futex_requeue_pi_wakeup_sync(). + * + * No need to do the full attach_to_pi_owner() exercise + * because @task is known and valid. + */ + if (set_waiters) { + raw_spin_lock_irq(&task->pi_lock); + __attach_to_pi_owner(task, key, ps); + raw_spin_unlock_irq(&task->pi_lock); + } + return 1; } /* @@ -1493,11 +1552,11 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q) */ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_state) { - u32 curval, newval; struct rt_mutex_waiter *top_waiter; struct task_struct *new_owner; bool postunlock = false; - DEFINE_WAKE_Q(wake_q); + DEFINE_RT_WAKE_Q(wqh); + u32 curval, newval; int ret = 0; top_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex); @@ -1549,14 +1608,14 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_ * not fail. */ pi_state_update_owner(pi_state, new_owner); - postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q); + postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wqh); } out_unlock: raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); if (postunlock) - rt_mutex_postunlock(&wake_q); + rt_mutex_postunlock(&wqh); return ret; } @@ -1793,6 +1852,108 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, q->key = *key2; } +static inline bool futex_requeue_pi_prepare(struct futex_q *q, + struct futex_pi_state *pi_state) +{ + int old, new; + + /* + * Set state to Q_REQUEUE_PI_IN_PROGRESS unless an early wakeup has + * already set Q_REQUEUE_PI_IGNORE to signal that requeue should + * ignore the waiter. + */ + old = atomic_read_acquire(&q->requeue_state); + do { + if (old == Q_REQUEUE_PI_IGNORE) + return false; + + /* + * futex_proxy_trylock_atomic() might have set it to + * IN_PROGRESS and a interleaved early wake to WAIT. + * + * It was considered to have an extra state for that + * trylock, but that would just add more conditionals + * all over the place for a dubious value. + */ + if (old != Q_REQUEUE_PI_NONE) + break; + + new = Q_REQUEUE_PI_IN_PROGRESS; + } while (!atomic_try_cmpxchg(&q->requeue_state, &old, new)); + + q->pi_state = pi_state; + return true; +} + +static inline void futex_requeue_pi_complete(struct futex_q *q, int locked) +{ + int old, new; + + old = atomic_read_acquire(&q->requeue_state); + do { + if (old == Q_REQUEUE_PI_IGNORE) + return; + + if (locked >= 0) { + /* Requeue succeeded. Set DONE or LOCKED */ + WARN_ON_ONCE(old != Q_REQUEUE_PI_IN_PROGRESS && + old != Q_REQUEUE_PI_WAIT); + new = Q_REQUEUE_PI_DONE + locked; + } else if (old == Q_REQUEUE_PI_IN_PROGRESS) { + /* Deadlock, no early wakeup interleave */ + new = Q_REQUEUE_PI_NONE; + } else { + /* Deadlock, early wakeup interleave. */ + WARN_ON_ONCE(old != Q_REQUEUE_PI_WAIT); + new = Q_REQUEUE_PI_IGNORE; + } + } while (!atomic_try_cmpxchg(&q->requeue_state, &old, new)); + +#ifdef CONFIG_PREEMPT_RT + /* If the waiter interleaved with the requeue let it know */ + if (unlikely(old == Q_REQUEUE_PI_WAIT)) + rcuwait_wake_up(&q->requeue_wait); +#endif +} + +static inline int futex_requeue_pi_wakeup_sync(struct futex_q *q) +{ + int old, new; + + old = atomic_read_acquire(&q->requeue_state); + do { + /* Is requeue done already? */ + if (old >= Q_REQUEUE_PI_DONE) + return old; + + /* + * If not done, then tell the requeue code to either ignore + * the waiter or to wake it up once the requeue is done. + */ + new = Q_REQUEUE_PI_WAIT; + if (old == Q_REQUEUE_PI_NONE) + new = Q_REQUEUE_PI_IGNORE; + } while (!atomic_try_cmpxchg(&q->requeue_state, &old, new)); + + /* If the requeue was in progress, wait for it to complete */ + if (old == Q_REQUEUE_PI_IN_PROGRESS) { +#ifdef CONFIG_PREEMPT_RT + rcuwait_wait_event(&q->requeue_wait, + atomic_read(&q->requeue_state) != Q_REQUEUE_PI_WAIT, + TASK_UNINTERRUPTIBLE); +#else + (void)atomic_cond_read_relaxed(&q->requeue_state, VAL != Q_REQUEUE_PI_WAIT); +#endif + } + + /* + * Requeue is now either prohibited or complete. Reread state + * because during the wait above it might have changed. Nothing + * will modify q->requeue_state after this point. + */ + return atomic_read(&q->requeue_state); +} + /** * requeue_pi_wake_futex() - Wake a task that acquired the lock during requeue * @q: the futex_q @@ -1800,12 +1961,26 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, * @hb: the hash_bucket of the requeue target futex * * During futex_requeue, with requeue_pi=1, it is possible to acquire the - * target futex if it is uncontended or via a lock steal. Set the futex_q key - * to the requeue target futex so the waiter can detect the wakeup on the right - * futex, but remove it from the hb and NULL the rt_waiter so it can detect - * atomic lock acquisition. Set the q->lock_ptr to the requeue target hb->lock - * to protect access to the pi_state to fixup the owner later. Must be called - * with both q->lock_ptr and hb->lock held. + * target futex if it is uncontended or via a lock steal. + * + * 1) Set @q::key to the requeue target futex key so the waiter can detect + * the wakeup on the right futex. + * + * 2) Dequeue @q from the hash bucket. + * + * 3) Set @q::rt_waiter to NULL so the woken up task can detect atomic lock + * acquisition. + * + * 4) Set the q->lock_ptr to the requeue target hb->lock for the case that + * the waiter has to fixup the pi state. + * + * 5) Complete the requeue state so the waiter can make progress. After + * this point the waiter task can return from the syscall immediately in + * case that the pi state does not have to be fixed up. + * + * 6) Wake the waiter task. + * + * Must be called with both q->lock_ptr and hb->lock held. */ static inline void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, @@ -1820,6 +1995,8 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, q->lock_ptr = &hb->lock; + /* Signal locked state to the waiter */ + futex_requeue_pi_complete(q, 1); wake_up_state(q->task, TASK_NORMAL); } @@ -1879,21 +2056,53 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1, if (!top_waiter) return 0; + /* + * Ensure that this is a waiter sitting in futex_wait_requeue_pi() + * and waiting on the 'waitqueue' futex which is always !PI. + */ + if (!top_waiter->rt_waiter || top_waiter->pi_state) + return -EINVAL; + /* Ensure we requeue to the expected futex. */ if (!match_futex(top_waiter->requeue_pi_key, key2)) return -EINVAL; + /* Ensure that this does not race against an early wakeup */ + if (!futex_requeue_pi_prepare(top_waiter, NULL)) + return -EAGAIN; + /* - * Try to take the lock for top_waiter. Set the FUTEX_WAITERS bit in - * the contended case or if set_waiters is 1. The pi_state is returned - * in ps in contended cases. + * Try to take the lock for top_waiter and set the FUTEX_WAITERS bit + * in the contended case or if @set_waiters is true. + * + * In the contended case PI state is attached to the lock owner. If + * the user space lock can be acquired then PI state is attached to + * the new owner (@top_waiter->task) when @set_waiters is true. */ vpid = task_pid_vnr(top_waiter->task); ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task, exiting, set_waiters); if (ret == 1) { + /* + * Lock was acquired in user space and PI state was + * attached to @top_waiter->task. That means state is fully + * consistent and the waiter can return to user space + * immediately after the wakeup. + */ requeue_pi_wake_futex(top_waiter, key2, hb2); - return vpid; + } else if (ret < 0) { + /* Rewind top_waiter::requeue_state */ + futex_requeue_pi_complete(top_waiter, ret); + } else { + /* + * futex_lock_pi_atomic() did not acquire the user space + * futex, but managed to establish the proxy lock and pi + * state. top_waiter::requeue_state cannot be fixed up here + * because the waiter is not enqueued on the rtmutex + * yet. This is handled at the callsite depending on the + * result of rt_mutex_start_proxy_lock() which is + * guaranteed to be reached with this function returning 0. + */ } return ret; } @@ -1948,23 +2157,35 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, return -EINVAL; /* + * futex_requeue() allows the caller to define the number + * of waiters to wake up via the @nr_wake argument. With + * REQUEUE_PI, waking up more than one waiter is creating + * more problems than it solves. Waking up a waiter makes + * only sense if the PI futex @uaddr2 is uncontended as + * this allows the requeue code to acquire the futex + * @uaddr2 before waking the waiter. The waiter can then + * return to user space without further action. A secondary + * wakeup would just make the futex_wait_requeue_pi() + * handling more complex, because that code would have to + * look up pi_state and do more or less all the handling + * which the requeue code has to do for the to be requeued + * waiters. So restrict the number of waiters to wake to + * one, and only wake it up when the PI futex is + * uncontended. Otherwise requeue it and let the unlock of + * the PI futex handle the wakeup. + * + * All REQUEUE_PI users, e.g. pthread_cond_signal() and + * pthread_cond_broadcast() must use nr_wake=1. + */ + if (nr_wake != 1) + return -EINVAL; + + /* * requeue_pi requires a pi_state, try to allocate it now * without any locks in case it fails. */ if (refill_pi_state_cache()) return -ENOMEM; - /* - * requeue_pi must wake as many tasks as it can, up to nr_wake - * + nr_requeue, since it acquires the rt_mutex prior to - * returning to userspace, so as to not leave the rt_mutex with - * waiters and no owner. However, second and third wake-ups - * cannot be predicted as they involve race conditions with the - * first wake and a fault while looking up the pi_state. Both - * pthread_cond_signal() and pthread_cond_broadcast() should - * use nr_wake=1. - */ - if (nr_wake != 1) - return -EINVAL; } retry: @@ -2014,7 +2235,7 @@ retry_private: } } - if (requeue_pi && (task_count - nr_wake < nr_requeue)) { + if (requeue_pi) { struct task_struct *exiting = NULL; /* @@ -2022,45 +2243,65 @@ retry_private: * intend to requeue waiters, force setting the FUTEX_WAITERS * bit. We force this here where we are able to easily handle * faults rather in the requeue loop below. + * + * Updates topwaiter::requeue_state if a top waiter exists. */ ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1, &key2, &pi_state, &exiting, nr_requeue); /* - * At this point the top_waiter has either taken uaddr2 or is - * waiting on it. If the former, then the pi_state will not - * exist yet, look it up one more time to ensure we have a - * reference to it. If the lock was taken, ret contains the - * vpid of the top waiter task. - * If the lock was not taken, we have pi_state and an initial - * refcount on it. In case of an error we have nothing. + * At this point the top_waiter has either taken uaddr2 or + * is waiting on it. In both cases pi_state has been + * established and an initial refcount on it. In case of an + * error there's nothing. + * + * The top waiter's requeue_state is up to date: + * + * - If the lock was acquired atomically (ret == 1), then + * the state is Q_REQUEUE_PI_LOCKED. + * + * The top waiter has been dequeued and woken up and can + * return to user space immediately. The kernel/user + * space state is consistent. In case that there must be + * more waiters requeued the WAITERS bit in the user + * space futex is set so the top waiter task has to go + * into the syscall slowpath to unlock the futex. This + * will block until this requeue operation has been + * completed and the hash bucket locks have been + * dropped. + * + * - If the trylock failed with an error (ret < 0) then + * the state is either Q_REQUEUE_PI_NONE, i.e. "nothing + * happened", or Q_REQUEUE_PI_IGNORE when there was an + * interleaved early wakeup. + * + * - If the trylock did not succeed (ret == 0) then the + * state is either Q_REQUEUE_PI_IN_PROGRESS or + * Q_REQUEUE_PI_WAIT if an early wakeup interleaved. + * This will be cleaned up in the loop below, which + * cannot fail because futex_proxy_trylock_atomic() did + * the same sanity checks for requeue_pi as the loop + * below does. */ - if (ret > 0) { - WARN_ON(pi_state); - task_count++; - /* - * If we acquired the lock, then the user space value - * of uaddr2 should be vpid. It cannot be changed by - * the top waiter as it is blocked on hb2 lock if it - * tries to do so. If something fiddled with it behind - * our back the pi state lookup might unearth it. So - * we rather use the known value than rereading and - * handing potential crap to lookup_pi_state. - * - * If that call succeeds then we have pi_state and an - * initial refcount on it. - */ - ret = lookup_pi_state(uaddr2, ret, hb2, &key2, - &pi_state, &exiting); - } - switch (ret) { case 0: /* We hold a reference on the pi state. */ break; - /* If the above failed, then pi_state is NULL */ + case 1: + /* + * futex_proxy_trylock_atomic() acquired the user space + * futex. Adjust task_count. + */ + task_count++; + ret = 0; + break; + + /* + * If the above failed, then pi_state is NULL and + * waiter::requeue_state is correct. + */ case -EFAULT: double_unlock_hb(hb1, hb2); hb_waiters_dec(hb2); @@ -2112,18 +2353,17 @@ retry_private: break; } - /* - * Wake nr_wake waiters. For requeue_pi, if we acquired the - * lock, we already woke the top_waiter. If not, it will be - * woken by futex_unlock_pi(). - */ - if (++task_count <= nr_wake && !requeue_pi) { - mark_wake_futex(&wake_q, this); + /* Plain futexes just wake or requeue and are done */ + if (!requeue_pi) { + if (++task_count <= nr_wake) + mark_wake_futex(&wake_q, this); + else + requeue_futex(this, hb1, hb2, &key2); continue; } /* Ensure we requeue to the expected futex for requeue_pi. */ - if (requeue_pi && !match_futex(this->requeue_pi_key, &key2)) { + if (!match_futex(this->requeue_pi_key, &key2)) { ret = -EINVAL; break; } @@ -2131,54 +2371,66 @@ retry_private: /* * Requeue nr_requeue waiters and possibly one more in the case * of requeue_pi if we couldn't acquire the lock atomically. + * + * Prepare the waiter to take the rt_mutex. Take a refcount + * on the pi_state and store the pointer in the futex_q + * object of the waiter. */ - if (requeue_pi) { + get_pi_state(pi_state); + + /* Don't requeue when the waiter is already on the way out. */ + if (!futex_requeue_pi_prepare(this, pi_state)) { /* - * Prepare the waiter to take the rt_mutex. Take a - * refcount on the pi_state and store the pointer in - * the futex_q object of the waiter. + * Early woken waiter signaled that it is on the + * way out. Drop the pi_state reference and try the + * next waiter. @this->pi_state is still NULL. */ - get_pi_state(pi_state); - this->pi_state = pi_state; - ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex, - this->rt_waiter, - this->task); - if (ret == 1) { - /* - * We got the lock. We do neither drop the - * refcount on pi_state nor clear - * this->pi_state because the waiter needs the - * pi_state for cleaning up the user space - * value. It will drop the refcount after - * doing so. - */ - requeue_pi_wake_futex(this, &key2, hb2); - continue; - } else if (ret) { - /* - * rt_mutex_start_proxy_lock() detected a - * potential deadlock when we tried to queue - * that waiter. Drop the pi_state reference - * which we took above and remove the pointer - * to the state from the waiters futex_q - * object. - */ - this->pi_state = NULL; - put_pi_state(pi_state); - /* - * We stop queueing more waiters and let user - * space deal with the mess. - */ - break; - } + put_pi_state(pi_state); + continue; + } + + ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex, + this->rt_waiter, + this->task); + + if (ret == 1) { + /* + * We got the lock. We do neither drop the refcount + * on pi_state nor clear this->pi_state because the + * waiter needs the pi_state for cleaning up the + * user space value. It will drop the refcount + * after doing so. this::requeue_state is updated + * in the wakeup as well. + */ + requeue_pi_wake_futex(this, &key2, hb2); + task_count++; + } else if (!ret) { + /* Waiter is queued, move it to hb2 */ + requeue_futex(this, hb1, hb2, &key2); + futex_requeue_pi_complete(this, 0); + task_count++; + } else { + /* + * rt_mutex_start_proxy_lock() detected a potential + * deadlock when we tried to queue that waiter. + * Drop the pi_state reference which we took above + * and remove the pointer to the state from the + * waiters futex_q object. + */ + this->pi_state = NULL; + put_pi_state(pi_state); + futex_requeue_pi_complete(this, ret); + /* + * We stop queueing more waiters and let user space + * deal with the mess. + */ + break; } - requeue_futex(this, hb1, hb2, &key2); } /* - * We took an extra initial reference to the pi_state either - * in futex_proxy_trylock_atomic() or in lookup_pi_state(). We - * need to drop it here again. + * We took an extra initial reference to the pi_state in + * futex_proxy_trylock_atomic(). We need to drop it here again. */ put_pi_state(pi_state); @@ -2357,7 +2609,7 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, * Modifying pi_state _before_ the user space value would leave the * pi_state in an inconsistent state when we fault here, because we * need to drop the locks to handle the fault. This might be observed - * in the PID check in lookup_pi_state. + * in the PID checks when attaching to PI state . */ retry: if (!argowner) { @@ -2614,8 +2866,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q, * * Setup the futex_q and locate the hash_bucket. Get the futex value and * compare it with the expected value. Handle atomic faults internally. - * Return with the hb lock held and a q.key reference on success, and unlocked - * with no q.key reference on failure. + * Return with the hb lock held on success, and unlocked on failure. * * Return: * - 0 - uaddr contains val and hb has been locked; @@ -2693,8 +2944,8 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, current->timer_slack_ns); retry: /* - * Prepare to wait on uaddr. On success, holds hb lock and increments - * q.key refs. + * Prepare to wait on uaddr. On success, it holds hb->lock and q + * is initialized. */ ret = futex_wait_setup(uaddr, val, flags, &q, &hb); if (ret) @@ -2705,7 +2956,6 @@ retry: /* If we were woken (and unqueued), we succeeded, whatever. */ ret = 0; - /* unqueue_me() drops q.key ref */ if (!unqueue_me(&q)) goto out; ret = -ETIMEDOUT; @@ -3072,27 +3322,22 @@ pi_faulted: } /** - * handle_early_requeue_pi_wakeup() - Detect early wakeup on the initial futex + * handle_early_requeue_pi_wakeup() - Handle early wakeup on the initial futex * @hb: the hash_bucket futex_q was original enqueued on * @q: the futex_q woken while waiting to be requeued - * @key2: the futex_key of the requeue target futex * @timeout: the timeout associated with the wait (NULL if none) * - * Detect if the task was woken on the initial futex as opposed to the requeue - * target futex. If so, determine if it was a timeout or a signal that caused - * the wakeup and return the appropriate error code to the caller. Must be - * called with the hb lock held. + * Determine the cause for the early wakeup. * * Return: - * - 0 = no early wakeup detected; - * - <0 = -ETIMEDOUT or -ERESTARTNOINTR + * -EWOULDBLOCK or -ETIMEDOUT or -ERESTARTNOINTR */ static inline int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, - struct futex_q *q, union futex_key *key2, + struct futex_q *q, struct hrtimer_sleeper *timeout) { - int ret = 0; + int ret; /* * With the hb lock held, we avoid races while we process the wakeup. @@ -3101,22 +3346,21 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, * It can't be requeued from uaddr2 to something else since we don't * support a PI aware source futex for requeue. */ - if (!match_futex(&q->key, key2)) { - WARN_ON(q->lock_ptr && (&hb->lock != q->lock_ptr)); - /* - * We were woken prior to requeue by a timeout or a signal. - * Unqueue the futex_q and determine which it was. - */ - plist_del(&q->list, &hb->chain); - hb_waiters_dec(hb); + WARN_ON_ONCE(&hb->lock != q->lock_ptr); - /* Handle spurious wakeups gracefully */ - ret = -EWOULDBLOCK; - if (timeout && !timeout->task) - ret = -ETIMEDOUT; - else if (signal_pending(current)) - ret = -ERESTARTNOINTR; - } + /* + * We were woken prior to requeue by a timeout or a signal. + * Unqueue the futex_q and determine which it was. + */ + plist_del(&q->list, &hb->chain); + hb_waiters_dec(hb); + + /* Handle spurious wakeups gracefully */ + ret = -EWOULDBLOCK; + if (timeout && !timeout->task) + ret = -ETIMEDOUT; + else if (signal_pending(current)) + ret = -ERESTARTNOINTR; return ret; } @@ -3169,6 +3413,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, struct futex_hash_bucket *hb; union futex_key key2 = FUTEX_KEY_INIT; struct futex_q q = futex_q_init; + struct rt_mutex_base *pi_mutex; int res, ret; if (!IS_ENABLED(CONFIG_FUTEX_PI)) @@ -3198,8 +3443,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, q.requeue_pi_key = &key2; /* - * Prepare to wait on uaddr. On success, increments q.key (key1) ref - * count. + * Prepare to wait on uaddr. On success, it holds hb->lock and q + * is initialized. */ ret = futex_wait_setup(uaddr, val, flags, &q, &hb); if (ret) @@ -3218,32 +3463,22 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, /* Queue the futex_q, drop the hb lock, wait for wakeup. */ futex_wait_queue_me(hb, &q, to); - spin_lock(&hb->lock); - ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to); - spin_unlock(&hb->lock); - if (ret) - goto out; - - /* - * In order for us to be here, we know our q.key == key2, and since - * we took the hb->lock above, we also know that futex_requeue() has - * completed and we no longer have to concern ourselves with a wakeup - * race with the atomic proxy lock acquisition by the requeue code. The - * futex_requeue dropped our key1 reference and incremented our key2 - * reference count. - */ + switch (futex_requeue_pi_wakeup_sync(&q)) { + case Q_REQUEUE_PI_IGNORE: + /* The waiter is still on uaddr1 */ + spin_lock(&hb->lock); + ret = handle_early_requeue_pi_wakeup(hb, &q, to); + spin_unlock(&hb->lock); + break; - /* - * Check if the requeue code acquired the second futex for us and do - * any pertinent fixup. - */ - if (!q.rt_waiter) { + case Q_REQUEUE_PI_LOCKED: + /* The requeue acquired the lock */ if (q.pi_state && (q.pi_state->owner != current)) { spin_lock(q.lock_ptr); ret = fixup_owner(uaddr2, &q, true); /* - * Drop the reference to the pi state which - * the requeue_pi() code acquired for us. + * Drop the reference to the pi state which the + * requeue_pi() code acquired for us. */ put_pi_state(q.pi_state); spin_unlock(q.lock_ptr); @@ -3253,18 +3488,14 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, */ ret = ret < 0 ? ret : 0; } - } else { - struct rt_mutex *pi_mutex; + break; - /* - * We have been woken up by futex_unlock_pi(), a timeout, or a - * signal. futex_unlock_pi() will not destroy the lock_ptr nor - * the pi_state. - */ - WARN_ON(!q.pi_state); + case Q_REQUEUE_PI_DONE: + /* Requeue completed. Current is 'pi_blocked_on' the rtmutex */ pi_mutex = &q.pi_state->pi_mutex; ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter); + /* Current is not longer pi_blocked_on */ spin_lock(q.lock_ptr); if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter)) ret = 0; @@ -3284,17 +3515,21 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, unqueue_me_pi(&q); spin_unlock(q.lock_ptr); - } - if (ret == -EINTR) { - /* - * We've already been requeued, but cannot restart by calling - * futex_lock_pi() directly. We could restart this syscall, but - * it would detect that the user space "val" changed and return - * -EWOULDBLOCK. Save the overhead of the restart and return - * -EWOULDBLOCK directly. - */ - ret = -EWOULDBLOCK; + if (ret == -EINTR) { + /* + * We've already been requeued, but cannot restart + * by calling futex_lock_pi() directly. We could + * restart this syscall, but it would detect that + * the user space "val" changed and return + * -EWOULDBLOCK. Save the overhead of the restart + * and return -EWOULDBLOCK directly. + */ + ret = -EWOULDBLOCK; + } + break; + default: + BUG(); } out: diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 221d80c31e94..1543934f26d2 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -190,12 +190,18 @@ irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) { - irqreturn_t retval; + struct pt_regs *regs = get_irq_regs(); + u64 ip = regs ? instruction_pointer(regs) : 0; unsigned int flags = 0; + irqreturn_t retval; retval = __handle_irq_event_percpu(desc, &flags); - add_interrupt_randomness(desc->irq_data.irq, flags); +#ifdef CONFIG_PREEMPT_RT + desc->random_ip = ip; +#else + add_interrupt_randomness(desc->irq_data.irq, flags, ip); +#endif if (!irq_settings_no_debug(desc)) note_interrupt(desc, retval); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index ef30b4762947..3f13b3d9cda9 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1260,6 +1260,8 @@ static int irq_thread(void *data) irqreturn_t (*handler_fn)(struct irq_desc *desc, struct irqaction *action); + sched_set_fifo(current); + if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD, &action->thread_flags)) handler_fn = irq_forced_thread_fn; @@ -1280,6 +1282,12 @@ static int irq_thread(void *data) if (action_ret == IRQ_WAKE_THREAD) irq_wake_secondary(desc, action); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + migrate_disable(); + add_interrupt_randomness(action->irq, 0, + desc->random_ip ^ (unsigned long) action); + migrate_enable(); + } wake_threads_waitq(desc); } @@ -1425,8 +1433,6 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary) if (IS_ERR(t)) return PTR_ERR(t); - sched_set_fifo(t); - /* * We keep the reference to the task struct even if * the thread dies to avoid that the interrupt code @@ -2828,7 +2834,7 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state); * This call sets the internal irqchip state of an interrupt, * depending on the value of @which. * - * This function should be called with preemption disabled if the + * This function should be called with migration disabled if the * interrupt controller has per-cpu registers. */ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index c481d8458325..ca4bdc53d6c7 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -447,6 +447,10 @@ MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true"); static int __init irqfixup_setup(char *str) { +#ifdef CONFIG_PREEMPT_RT + pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT\n"); + return 1; +#endif irqfixup = 1; printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n"); printk(KERN_WARNING "This may impact system performance.\n"); @@ -459,6 +463,10 @@ module_param(irqfixup, int, 0644); static int __init irqpoll_setup(char *str) { +#ifdef CONFIG_PREEMPT_RT + pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT\n"); + return 1; +#endif irqfixup = 2; printk(KERN_WARNING "Misrouted IRQ fixup and polling support " "enabled\n"); diff --git a/kernel/irq_work.c b/kernel/irq_work.c index db8c248ebc8c..14c2aba4c947 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -18,6 +18,7 @@ #include <linux/cpu.h> #include <linux/notifier.h> #include <linux/smp.h> +#include <linux/interrupt.h> #include <asm/processor.h> #include <linux/kasan.h> @@ -52,13 +53,27 @@ void __weak arch_irq_work_raise(void) /* Enqueue on current CPU, work must already be claimed and preempt disabled */ static void __irq_work_queue_local(struct irq_work *work) { - /* If the work is "lazy", handle it from next tick if any */ - if (atomic_read(&work->node.a_flags) & IRQ_WORK_LAZY) { - if (llist_add(&work->node.llist, this_cpu_ptr(&lazy_list)) && - tick_nohz_tick_stopped()) - arch_irq_work_raise(); - } else { - if (llist_add(&work->node.llist, this_cpu_ptr(&raised_list))) + struct llist_head *list; + bool lazy_work; + int work_flags; + + work_flags = atomic_read(&work->node.a_flags); + if (work_flags & IRQ_WORK_LAZY) + lazy_work = true; + else if (IS_ENABLED(CONFIG_PREEMPT_RT) && + !(work_flags & IRQ_WORK_HARD_IRQ)) + lazy_work = true; + else + lazy_work = false; + + if (lazy_work) + list = this_cpu_ptr(&lazy_list); + else + list = this_cpu_ptr(&raised_list); + + if (llist_add(&work->node.llist, list)) { + /* If the work is "lazy", handle it from next tick if any */ + if (!lazy_work || tick_nohz_tick_stopped()) arch_irq_work_raise(); } } @@ -104,7 +119,14 @@ bool irq_work_queue_on(struct irq_work *work, int cpu) if (cpu != smp_processor_id()) { /* Arch remote IPI send/receive backend aren't NMI safe */ WARN_ON_ONCE(in_nmi()); - __smp_call_single_queue(cpu, &work->node.llist); + + if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ)) { + if (llist_add(&work->node.llist, &per_cpu(lazy_list, cpu))) + /* && tick_nohz_tick_stopped_cpu(cpu) */ + arch_send_call_function_single_ipi(cpu); + } else { + __smp_call_single_queue(cpu, &work->node.llist); + } } else { __irq_work_queue_local(work); } @@ -122,9 +144,8 @@ bool irq_work_needs_cpu(void) raised = this_cpu_ptr(&raised_list); lazy = this_cpu_ptr(&lazy_list); - if (llist_empty(raised) || arch_irq_work_has_interrupt()) - if (llist_empty(lazy)) - return false; + if (llist_empty(raised) && llist_empty(lazy)) + return false; /* All work should have been flushed before going offline */ WARN_ON_ONCE(cpu_is_offline(smp_processor_id())); @@ -160,6 +181,10 @@ void irq_work_single(void *arg) * else claimed it meanwhile. */ (void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY); + + if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) || + !arch_irq_work_has_interrupt()) + rcuwait_wake_up(&work->irqwait); } static void irq_work_run_list(struct llist_head *list) @@ -167,8 +192,12 @@ static void irq_work_run_list(struct llist_head *list) struct irq_work *work, *tmp; struct llist_node *llnode; +#ifndef CONFIG_PREEMPT_RT + /* + * nort: On RT IRQ-work may run in SOFTIRQ context. + */ BUG_ON(!irqs_disabled()); - +#endif if (llist_empty(list)) return; @@ -184,7 +213,16 @@ static void irq_work_run_list(struct llist_head *list) void irq_work_run(void) { irq_work_run_list(this_cpu_ptr(&raised_list)); - irq_work_run_list(this_cpu_ptr(&lazy_list)); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + /* + * NOTE: we raise softirq via IPI for safety, + * and execute in irq_work_tick() to move the + * overhead from hard to soft irq context. + */ + if (!llist_empty(this_cpu_ptr(&lazy_list))) + raise_softirq(TIMER_SOFTIRQ); + } else + irq_work_run_list(this_cpu_ptr(&lazy_list)); } EXPORT_SYMBOL_GPL(irq_work_run); @@ -194,8 +232,17 @@ void irq_work_tick(void) if (!llist_empty(raised) && !arch_irq_work_has_interrupt()) irq_work_run_list(raised); + + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + irq_work_run_list(this_cpu_ptr(&lazy_list)); +} + +#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT) +void irq_work_tick_soft(void) +{ irq_work_run_list(this_cpu_ptr(&lazy_list)); } +#endif /* * Synchronize against the irq_work @entry, ensures the entry is not @@ -204,6 +251,14 @@ void irq_work_tick(void) void irq_work_sync(struct irq_work *work) { lockdep_assert_irqs_enabled(); + might_sleep(); + + if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) || + !arch_irq_work_has_interrupt()) { + rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work), + TASK_UNINTERRUPTIBLE); + return; + } while (irq_work_is_busy(work)) cpu_relax(); diff --git a/kernel/kcov.c b/kernel/kcov.c index 80bfe71bbe13..36ca640c4f8e 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -88,6 +88,7 @@ static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas); struct kcov_percpu_data { void *irq_area; + local_lock_t lock; unsigned int saved_mode; unsigned int saved_size; @@ -96,7 +97,9 @@ struct kcov_percpu_data { int saved_sequence; }; -static DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data); +static DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data) = { + .lock = INIT_LOCAL_LOCK(lock), +}; /* Must be called with kcov_remote_lock locked. */ static struct kcov_remote *kcov_remote_find(u64 handle) @@ -824,7 +827,7 @@ void kcov_remote_start(u64 handle) if (!in_task() && !in_serving_softirq()) return; - local_irq_save(flags); + local_lock_irqsave(&kcov_percpu_data.lock, flags); /* * Check that kcov_remote_start() is not called twice in background @@ -832,7 +835,7 @@ void kcov_remote_start(u64 handle) */ mode = READ_ONCE(t->kcov_mode); if (WARN_ON(in_task() && kcov_mode_enabled(mode))) { - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } /* @@ -841,14 +844,15 @@ void kcov_remote_start(u64 handle) * happened while collecting coverage from a background thread. */ if (WARN_ON(in_serving_softirq() && t->kcov_softirq)) { - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } spin_lock(&kcov_remote_lock); remote = kcov_remote_find(handle); if (!remote) { - spin_unlock_irqrestore(&kcov_remote_lock, flags); + spin_unlock(&kcov_remote_lock); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } kcov_debug("handle = %llx, context: %s\n", handle, @@ -869,19 +873,19 @@ void kcov_remote_start(u64 handle) size = CONFIG_KCOV_IRQ_AREA_SIZE; area = this_cpu_ptr(&kcov_percpu_data)->irq_area; } - spin_unlock_irqrestore(&kcov_remote_lock, flags); + spin_unlock(&kcov_remote_lock); /* Can only happen when in_task(). */ if (!area) { + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); area = vmalloc(size * sizeof(unsigned long)); if (!area) { kcov_put(kcov); return; } + local_lock_irqsave(&kcov_percpu_data.lock, flags); } - local_irq_save(flags); - /* Reset coverage size. */ *(u64 *)area = 0; @@ -891,7 +895,7 @@ void kcov_remote_start(u64 handle) } kcov_start(t, kcov, size, area, mode, sequence); - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); } EXPORT_SYMBOL(kcov_remote_start); @@ -965,12 +969,12 @@ void kcov_remote_stop(void) if (!in_task() && !in_serving_softirq()) return; - local_irq_save(flags); + local_lock_irqsave(&kcov_percpu_data.lock, flags); mode = READ_ONCE(t->kcov_mode); barrier(); if (!kcov_mode_enabled(mode)) { - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } /* @@ -978,12 +982,12 @@ void kcov_remote_stop(void) * actually found the remote handle and started collecting coverage. */ if (in_serving_softirq() && !t->kcov_softirq) { - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } /* Make sure that kcov_softirq is only set when in softirq. */ if (WARN_ON(!in_serving_softirq() && t->kcov_softirq)) { - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); return; } @@ -1013,7 +1017,7 @@ void kcov_remote_stop(void) spin_unlock(&kcov_remote_lock); } - local_irq_restore(flags); + local_unlock_irqrestore(&kcov_percpu_data.lock, flags); /* Get in kcov_remote_start(). */ kcov_put(kcov); @@ -1034,8 +1038,8 @@ static int __init kcov_init(void) int cpu; for_each_possible_cpu(cpu) { - void *area = vmalloc(CONFIG_KCOV_IRQ_AREA_SIZE * - sizeof(unsigned long)); + void *area = vmalloc_node(CONFIG_KCOV_IRQ_AREA_SIZE * + sizeof(unsigned long), cpu_to_node(cpu)); if (!area) return -ENOMEM; per_cpu_ptr(&kcov_percpu_data, cpu)->irq_area = area; diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 4b34a9aa32bc..5a5d192a89ac 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -979,7 +979,6 @@ void crash_kexec(struct pt_regs *regs) old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); if (old_cpu == PANIC_CPU_INVALID) { /* This is the 1st CPU which comes here, so go ahead. */ - printk_safe_flush_on_panic(); __crash_kexec(regs); /* diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 35859da8bd4f..dfff31ed644a 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -138,6 +138,15 @@ KERNEL_ATTR_RO(vmcoreinfo); #endif /* CONFIG_CRASH_CORE */ +#if defined(CONFIG_PREEMPT_RT) +static ssize_t realtime_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", 1); +} +KERNEL_ATTR_RO(realtime); +#endif + /* whether file capabilities are enabled */ static ssize_t fscaps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -229,6 +238,9 @@ static struct attribute * kernel_attrs[] = { &rcu_expedited_attr.attr, &rcu_normal_attr.attr, #endif +#ifdef CONFIG_PREEMPT_RT + &realtime_attr.attr, +#endif NULL }; diff --git a/kernel/kthread.c b/kernel/kthread.c index 5b37a8567168..4a4d7092a2d8 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -270,6 +270,7 @@ EXPORT_SYMBOL_GPL(kthread_parkme); static int kthread(void *_create) { + static const struct sched_param param = { .sched_priority = 0 }; /* Copy data: it's on kthread's stack */ struct kthread_create_info *create = _create; int (*threadfn)(void *data) = create->threadfn; @@ -300,6 +301,13 @@ static int kthread(void *_create) init_completion(&self->parked); current->vfork_done = &self->exited; + /* + * The new thread inherited kthreadd's priority and CPU mask. Reset + * back to default in case they have been changed. + */ + sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m); + set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_KTHREAD)); + /* OK, tell user we're spawned, wait for stop or wakeup */ __set_current_state(TASK_UNINTERRUPTIBLE); create->result = current; @@ -397,7 +405,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), } task = create->result; if (!IS_ERR(task)) { - static const struct sched_param param = { .sched_priority = 0 }; char name[TASK_COMM_LEN]; /* @@ -406,13 +413,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), */ vsnprintf(name, sizeof(name), namefmt, args); set_task_comm(task, name); - /* - * root may have changed our (kthreadd's) priority or CPU mask. - * The kernel thread should not inherit these properties. - */ - sched_setscheduler_nocheck(task, SCHED_NORMAL, ¶m); - set_cpus_allowed_ptr(task, - housekeeping_cpumask(HK_FLAG_KTHREAD)); } kfree(create); return task; diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index 3572808223e4..d51cabf28f38 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -24,7 +24,8 @@ obj-$(CONFIG_SMP) += spinlock.o obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o obj-$(CONFIG_PROVE_LOCKING) += spinlock.o obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o -obj-$(CONFIG_RT_MUTEXES) += rtmutex.o +obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o +obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o ww_rt_mutex.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 0627584f7872..5bef051a55c5 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5475,6 +5475,7 @@ static noinstr void check_flags(unsigned long flags) } } +#ifndef CONFIG_PREEMPT_RT /* * We dont accurately track softirq state in e.g. * hardirq contexts (such as on 4KSTACKS), so only @@ -5489,6 +5490,7 @@ static noinstr void check_flags(unsigned long flags) DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); } } +#endif if (!debug_locks) print_irqtrace_events(current); diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c index db9301591e3f..bc8abb8549d2 100644 --- a/kernel/locking/mutex-debug.c +++ b/kernel/locking/mutex-debug.c @@ -1,6 +1,4 @@ /* - * kernel/mutex-debug.c - * * Debugging code for mutexes * * Started by Ingo Molnar: @@ -22,7 +20,7 @@ #include <linux/interrupt.h> #include <linux/debug_locks.h> -#include "mutex-debug.h" +#include "mutex.h" /* * Must be called with lock->wait_lock held. @@ -32,6 +30,7 @@ void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter)); waiter->magic = waiter; INIT_LIST_HEAD(&waiter->list); + waiter->ww_ctx = MUTEX_POISON_WW_CTX; } void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter) diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h deleted file mode 100644 index 53e631e1d76d..000000000000 --- a/kernel/locking/mutex-debug.h +++ /dev/null @@ -1,29 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * Mutexes: blocking mutual exclusion locks - * - * started by Ingo Molnar: - * - * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> - * - * This file contains mutex debugging related internal declarations, - * prototypes and inline functions, for the CONFIG_DEBUG_MUTEXES case. - * More details are in kernel/mutex-debug.c. - */ - -/* - * This must be called with lock->wait_lock held. - */ -extern void debug_mutex_lock_common(struct mutex *lock, - struct mutex_waiter *waiter); -extern void debug_mutex_wake_waiter(struct mutex *lock, - struct mutex_waiter *waiter); -extern void debug_mutex_free_waiter(struct mutex_waiter *waiter); -extern void debug_mutex_add_waiter(struct mutex *lock, - struct mutex_waiter *waiter, - struct task_struct *task); -extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter, - struct task_struct *task); -extern void debug_mutex_unlock(struct mutex *lock); -extern void debug_mutex_init(struct mutex *lock, const char *name, - struct lock_class_key *key); diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index fb30e1436dfb..2b609c2e1084 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -30,17 +30,14 @@ #include <linux/debug_locks.h> #include <linux/osq_lock.h> -#ifdef CONFIG_DEBUG_MUTEXES -# include "mutex-debug.h" -#else -# include "mutex.h" -#endif +#ifndef CONFIG_PREEMPT_RT +#include "mutex.h" void __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key) { atomic_long_set(&lock->owner, 0); - spin_lock_init(&lock->wait_lock); + raw_spin_lock_init(&lock->wait_lock); INIT_LIST_HEAD(&lock->wait_list); #ifdef CONFIG_MUTEX_SPIN_ON_OWNER osq_lock_init(&lock->osq); @@ -286,215 +283,7 @@ void __sched mutex_lock(struct mutex *lock) EXPORT_SYMBOL(mutex_lock); #endif -/* - * Wait-Die: - * The newer transactions are killed when: - * It (the new transaction) makes a request for a lock being held - * by an older transaction. - * - * Wound-Wait: - * The newer transactions are wounded when: - * An older transaction makes a request for a lock being held by - * the newer transaction. - */ - -/* - * Associate the ww_mutex @ww with the context @ww_ctx under which we acquired - * it. - */ -static __always_inline void -ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx) -{ -#ifdef CONFIG_DEBUG_MUTEXES - /* - * If this WARN_ON triggers, you used ww_mutex_lock to acquire, - * but released with a normal mutex_unlock in this call. - * - * This should never happen, always use ww_mutex_unlock. - */ - DEBUG_LOCKS_WARN_ON(ww->ctx); - - /* - * Not quite done after calling ww_acquire_done() ? - */ - DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire); - - if (ww_ctx->contending_lock) { - /* - * After -EDEADLK you tried to - * acquire a different ww_mutex? Bad! - */ - DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww); - - /* - * You called ww_mutex_lock after receiving -EDEADLK, - * but 'forgot' to unlock everything else first? - */ - DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0); - ww_ctx->contending_lock = NULL; - } - - /* - * Naughty, using a different class will lead to undefined behavior! - */ - DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class); -#endif - ww_ctx->acquired++; - ww->ctx = ww_ctx; -} - -/* - * Determine if context @a is 'after' context @b. IOW, @a is a younger - * transaction than @b and depending on algorithm either needs to wait for - * @b or die. - */ -static inline bool __sched -__ww_ctx_stamp_after(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b) -{ - - return (signed long)(a->stamp - b->stamp) > 0; -} - -/* - * Wait-Die; wake a younger waiter context (when locks held) such that it can - * die. - * - * Among waiters with context, only the first one can have other locks acquired - * already (ctx->acquired > 0), because __ww_mutex_add_waiter() and - * __ww_mutex_check_kill() wake any but the earliest context. - */ -static bool __sched -__ww_mutex_die(struct mutex *lock, struct mutex_waiter *waiter, - struct ww_acquire_ctx *ww_ctx) -{ - if (!ww_ctx->is_wait_die) - return false; - - if (waiter->ww_ctx->acquired > 0 && - __ww_ctx_stamp_after(waiter->ww_ctx, ww_ctx)) { - debug_mutex_wake_waiter(lock, waiter); - wake_up_process(waiter->task); - } - - return true; -} - -/* - * Wound-Wait; wound a younger @hold_ctx if it holds the lock. - * - * Wound the lock holder if there are waiters with older transactions than - * the lock holders. Even if multiple waiters may wound the lock holder, - * it's sufficient that only one does. - */ -static bool __ww_mutex_wound(struct mutex *lock, - struct ww_acquire_ctx *ww_ctx, - struct ww_acquire_ctx *hold_ctx) -{ - struct task_struct *owner = __mutex_owner(lock); - - lockdep_assert_held(&lock->wait_lock); - - /* - * Possible through __ww_mutex_add_waiter() when we race with - * ww_mutex_set_context_fastpath(). In that case we'll get here again - * through __ww_mutex_check_waiters(). - */ - if (!hold_ctx) - return false; - - /* - * Can have !owner because of __mutex_unlock_slowpath(), but if owner, - * it cannot go away because we'll have FLAG_WAITERS set and hold - * wait_lock. - */ - if (!owner) - return false; - - if (ww_ctx->acquired > 0 && __ww_ctx_stamp_after(hold_ctx, ww_ctx)) { - hold_ctx->wounded = 1; - - /* - * wake_up_process() paired with set_current_state() - * inserts sufficient barriers to make sure @owner either sees - * it's wounded in __ww_mutex_check_kill() or has a - * wakeup pending to re-read the wounded state. - */ - if (owner != current) - wake_up_process(owner); - - return true; - } - - return false; -} - -/* - * We just acquired @lock under @ww_ctx, if there are later contexts waiting - * behind us on the wait-list, check if they need to die, or wound us. - * - * See __ww_mutex_add_waiter() for the list-order construction; basically the - * list is ordered by stamp, smallest (oldest) first. - * - * This relies on never mixing wait-die/wound-wait on the same wait-list; - * which is currently ensured by that being a ww_class property. - * - * The current task must not be on the wait list. - */ -static void __sched -__ww_mutex_check_waiters(struct mutex *lock, struct ww_acquire_ctx *ww_ctx) -{ - struct mutex_waiter *cur; - - lockdep_assert_held(&lock->wait_lock); - - list_for_each_entry(cur, &lock->wait_list, list) { - if (!cur->ww_ctx) - continue; - - if (__ww_mutex_die(lock, cur, ww_ctx) || - __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx)) - break; - } -} - -/* - * After acquiring lock with fastpath, where we do not hold wait_lock, set ctx - * and wake up any waiters so they can recheck. - */ -static __always_inline void -ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) -{ - ww_mutex_lock_acquired(lock, ctx); - - /* - * The lock->ctx update should be visible on all cores before - * the WAITERS check is done, otherwise contended waiters might be - * missed. The contended waiters will either see ww_ctx == NULL - * and keep spinning, or it will acquire wait_lock, add itself - * to waiter list and sleep. - */ - smp_mb(); /* See comments above and below. */ - - /* - * [W] ww->ctx = ctx [W] MUTEX_FLAG_WAITERS - * MB MB - * [R] MUTEX_FLAG_WAITERS [R] ww->ctx - * - * The memory barrier above pairs with the memory barrier in - * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx - * and/or !empty list. - */ - if (likely(!(atomic_long_read(&lock->base.owner) & MUTEX_FLAG_WAITERS))) - return; - - /* - * Uh oh, we raced in fastpath, check if any of the waiters need to - * die or wound us. - */ - spin_lock(&lock->base.wait_lock); - __ww_mutex_check_waiters(&lock->base, ctx); - spin_unlock(&lock->base.wait_lock); -} +#include "ww_mutex.h" #ifdef CONFIG_MUTEX_SPIN_ON_OWNER @@ -754,171 +543,11 @@ EXPORT_SYMBOL(mutex_unlock); */ void __sched ww_mutex_unlock(struct ww_mutex *lock) { - /* - * The unlocking fastpath is the 0->1 transition from 'locked' - * into 'unlocked' state: - */ - if (lock->ctx) { -#ifdef CONFIG_DEBUG_MUTEXES - DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired); -#endif - if (lock->ctx->acquired > 0) - lock->ctx->acquired--; - lock->ctx = NULL; - } - + __ww_mutex_unlock(lock); mutex_unlock(&lock->base); } EXPORT_SYMBOL(ww_mutex_unlock); - -static __always_inline int __sched -__ww_mutex_kill(struct mutex *lock, struct ww_acquire_ctx *ww_ctx) -{ - if (ww_ctx->acquired > 0) { -#ifdef CONFIG_DEBUG_MUTEXES - struct ww_mutex *ww; - - ww = container_of(lock, struct ww_mutex, base); - DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock); - ww_ctx->contending_lock = ww; -#endif - return -EDEADLK; - } - - return 0; -} - - -/* - * Check the wound condition for the current lock acquire. - * - * Wound-Wait: If we're wounded, kill ourself. - * - * Wait-Die: If we're trying to acquire a lock already held by an older - * context, kill ourselves. - * - * Since __ww_mutex_add_waiter() orders the wait-list on stamp, we only have to - * look at waiters before us in the wait-list. - */ -static inline int __sched -__ww_mutex_check_kill(struct mutex *lock, struct mutex_waiter *waiter, - struct ww_acquire_ctx *ctx) -{ - struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); - struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx); - struct mutex_waiter *cur; - - if (ctx->acquired == 0) - return 0; - - if (!ctx->is_wait_die) { - if (ctx->wounded) - return __ww_mutex_kill(lock, ctx); - - return 0; - } - - if (hold_ctx && __ww_ctx_stamp_after(ctx, hold_ctx)) - return __ww_mutex_kill(lock, ctx); - - /* - * If there is a waiter in front of us that has a context, then its - * stamp is earlier than ours and we must kill ourself. - */ - cur = waiter; - list_for_each_entry_continue_reverse(cur, &lock->wait_list, list) { - if (!cur->ww_ctx) - continue; - - return __ww_mutex_kill(lock, ctx); - } - - return 0; -} - -/* - * Add @waiter to the wait-list, keep the wait-list ordered by stamp, smallest - * first. Such that older contexts are preferred to acquire the lock over - * younger contexts. - * - * Waiters without context are interspersed in FIFO order. - * - * Furthermore, for Wait-Die kill ourself immediately when possible (there are - * older contexts already waiting) to avoid unnecessary waiting and for - * Wound-Wait ensure we wound the owning context when it is younger. - */ -static inline int __sched -__ww_mutex_add_waiter(struct mutex_waiter *waiter, - struct mutex *lock, - struct ww_acquire_ctx *ww_ctx) -{ - struct mutex_waiter *cur; - struct list_head *pos; - bool is_wait_die; - - if (!ww_ctx) { - __mutex_add_waiter(lock, waiter, &lock->wait_list); - return 0; - } - - is_wait_die = ww_ctx->is_wait_die; - - /* - * Add the waiter before the first waiter with a higher stamp. - * Waiters without a context are skipped to avoid starving - * them. Wait-Die waiters may die here. Wound-Wait waiters - * never die here, but they are sorted in stamp order and - * may wound the lock holder. - */ - pos = &lock->wait_list; - list_for_each_entry_reverse(cur, &lock->wait_list, list) { - if (!cur->ww_ctx) - continue; - - if (__ww_ctx_stamp_after(ww_ctx, cur->ww_ctx)) { - /* - * Wait-Die: if we find an older context waiting, there - * is no point in queueing behind it, as we'd have to - * die the moment it would acquire the lock. - */ - if (is_wait_die) { - int ret = __ww_mutex_kill(lock, ww_ctx); - - if (ret) - return ret; - } - - break; - } - - pos = &cur->list; - - /* Wait-Die: ensure younger waiters die. */ - __ww_mutex_die(lock, cur, ww_ctx); - } - - __mutex_add_waiter(lock, waiter, pos); - - /* - * Wound-Wait: if we're blocking on a mutex owned by a younger context, - * wound that such that we might proceed. - */ - if (!is_wait_die) { - struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); - - /* - * See ww_mutex_set_context_fastpath(). Orders setting - * MUTEX_FLAG_WAITERS vs the ww->ctx load, - * such that either we or the fastpath will wound @ww->ctx. - */ - smp_mb(); - __ww_mutex_wound(lock, ww_ctx, ww->ctx); - } - - return 0; -} - /* * Lock a mutex (possibly interruptible), slowpath: */ @@ -952,6 +581,10 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas */ if (ww_ctx->acquired == 0) ww_ctx->wounded = 0; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + nest_lock = &ww_ctx->dep_map; +#endif } preempt_disable(); @@ -967,7 +600,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas return 0; } - spin_lock(&lock->wait_lock); + raw_spin_lock(&lock->wait_lock); /* * After waiting to acquire the wait_lock, try again. */ @@ -979,17 +612,15 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } debug_mutex_lock_common(lock, &waiter); + waiter.task = current; + if (use_ww_ctx) + waiter.ww_ctx = ww_ctx; lock_contended(&lock->dep_map, ip); if (!use_ww_ctx) { /* add waiting tasks to the end of the waitqueue (FIFO): */ __mutex_add_waiter(lock, &waiter, &lock->wait_list); - - -#ifdef CONFIG_DEBUG_MUTEXES - waiter.ww_ctx = MUTEX_POISON_WW_CTX; -#endif } else { /* * Add in stamp order, waking up waiters that must kill @@ -998,12 +629,8 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx); if (ret) goto err_early_kill; - - waiter.ww_ctx = ww_ctx; } - waiter.task = current; - set_current_state(state); for (;;) { bool first; @@ -1033,7 +660,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err; } - spin_unlock(&lock->wait_lock); + raw_spin_unlock(&lock->wait_lock); schedule_preempt_disabled(); first = __mutex_waiter_is_first(lock, &waiter); @@ -1050,9 +677,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas (first && mutex_optimistic_spin(lock, ww_ctx, &waiter))) break; - spin_lock(&lock->wait_lock); + raw_spin_lock(&lock->wait_lock); } - spin_lock(&lock->wait_lock); + raw_spin_lock(&lock->wait_lock); acquired: __set_current_state(TASK_RUNNING); @@ -1077,7 +704,7 @@ skip_wait: if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); - spin_unlock(&lock->wait_lock); + raw_spin_unlock(&lock->wait_lock); preempt_enable(); return 0; @@ -1085,7 +712,7 @@ err: __set_current_state(TASK_RUNNING); __mutex_remove_waiter(lock, &waiter); err_early_kill: - spin_unlock(&lock->wait_lock); + raw_spin_unlock(&lock->wait_lock); debug_mutex_free_waiter(&waiter); mutex_release(&lock->dep_map, ip); preempt_enable(); @@ -1101,10 +728,9 @@ __mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass, static int __sched __ww_mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass, - struct lockdep_map *nest_lock, unsigned long ip, - struct ww_acquire_ctx *ww_ctx) + unsigned long ip, struct ww_acquire_ctx *ww_ctx) { - return __mutex_lock_common(lock, state, subclass, nest_lock, ip, ww_ctx, true); + return __mutex_lock_common(lock, state, subclass, NULL, ip, ww_ctx, true); } #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -1184,8 +810,7 @@ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) might_sleep(); ret = __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, - 0, ctx ? &ctx->dep_map : NULL, _RET_IP_, - ctx); + 0, _RET_IP_, ctx); if (!ret && ctx && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); @@ -1200,8 +825,7 @@ ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) might_sleep(); ret = __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, - 0, ctx ? &ctx->dep_map : NULL, _RET_IP_, - ctx); + 0, _RET_IP_, ctx); if (!ret && ctx && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); @@ -1254,7 +878,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne owner = old; } - spin_lock(&lock->wait_lock); + raw_spin_lock(&lock->wait_lock); debug_mutex_unlock(lock); if (!list_empty(&lock->wait_list)) { /* get the first entry from the wait-list: */ @@ -1271,7 +895,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne if (owner & MUTEX_FLAG_HANDOFF) __mutex_handoff(lock, next); - spin_unlock(&lock->wait_lock); + raw_spin_unlock(&lock->wait_lock); wake_up_q(&wake_q); } @@ -1375,7 +999,7 @@ __mutex_lock_interruptible_slowpath(struct mutex *lock) static noinline int __sched __ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { - return __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, 0, NULL, + return __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, 0, _RET_IP_, ctx); } @@ -1383,7 +1007,7 @@ static noinline int __sched __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { - return __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, 0, NULL, + return __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, 0, _RET_IP_, ctx); } @@ -1450,7 +1074,8 @@ ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) } EXPORT_SYMBOL(ww_mutex_lock_interruptible); -#endif +#endif /* !CONFIG_DEBUG_LOCK_ALLOC */ +#endif /* !CONFIG_PREEMPT_RT */ /** * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0 diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h index f0c710b1d192..0b2a79c4013b 100644 --- a/kernel/locking/mutex.h +++ b/kernel/locking/mutex.h @@ -5,19 +5,41 @@ * started by Ingo Molnar: * * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> - * - * This file contains mutex debugging related internal prototypes, for the - * !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs: */ -#define debug_mutex_wake_waiter(lock, waiter) do { } while (0) -#define debug_mutex_free_waiter(waiter) do { } while (0) -#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0) -#define debug_mutex_remove_waiter(lock, waiter, ti) do { } while (0) -#define debug_mutex_unlock(lock) do { } while (0) -#define debug_mutex_init(lock, name, key) do { } while (0) +/* + * This is the control structure for tasks blocked on mutex, which resides + * on the blocked task's kernel stack: + */ +struct mutex_waiter { + struct list_head list; + struct task_struct *task; + struct ww_acquire_ctx *ww_ctx; +#ifdef CONFIG_DEBUG_MUTEXES + void *magic; +#endif +}; -static inline void -debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) -{ -} +#ifdef CONFIG_DEBUG_MUTEXES +extern void debug_mutex_lock_common(struct mutex *lock, + struct mutex_waiter *waiter); +extern void debug_mutex_wake_waiter(struct mutex *lock, + struct mutex_waiter *waiter); +extern void debug_mutex_free_waiter(struct mutex_waiter *waiter); +extern void debug_mutex_add_waiter(struct mutex *lock, + struct mutex_waiter *waiter, + struct task_struct *task); +extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter, + struct task_struct *task); +extern void debug_mutex_unlock(struct mutex *lock); +extern void debug_mutex_init(struct mutex *lock, const char *name, + struct lock_class_key *key); +#else /* CONFIG_DEBUG_MUTEXES */ +# define debug_mutex_lock_common(lock, waiter) do { } while (0) +# define debug_mutex_wake_waiter(lock, waiter) do { } while (0) +# define debug_mutex_free_waiter(waiter) do { } while (0) +# define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0) +# define debug_mutex_remove_waiter(lock, waiter, ti) do { } while (0) +# define debug_mutex_unlock(lock) do { } while (0) +# define debug_mutex_init(lock, name, key) do { } while (0) +#endif /* !CONFIG_DEBUG_MUTEXES */ diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 1a7e3f838077..3665583361c0 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -8,20 +8,58 @@ * Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com> * Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt * Copyright (C) 2006 Esben Nielsen + * Adaptive Spinlocks: + * Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich, + * and Peter Morreale, + * Adaptive Spinlocks simplification: + * Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com> * * See Documentation/locking/rt-mutex-design.rst for details. */ -#include <linux/spinlock.h> -#include <linux/export.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/deadline.h> #include <linux/sched/signal.h> #include <linux/sched/rt.h> -#include <linux/sched/deadline.h> #include <linux/sched/wake_q.h> -#include <linux/sched/debug.h> -#include <linux/timer.h> +#include <linux/ww_mutex.h> #include "rtmutex_common.h" +#ifndef WW_RT +# define build_ww_mutex() (false) +# define ww_container_of(rtm) NULL + +static inline int __ww_mutex_add_waiter(struct rt_mutex_waiter *waiter, + struct rt_mutex *lock, + struct ww_acquire_ctx *ww_ctx) +{ + return 0; +} + +static inline void __ww_mutex_check_waiters(struct rt_mutex *lock, + struct ww_acquire_ctx *ww_ctx) +{ +} + +static inline void ww_mutex_lock_acquired(struct ww_mutex *lock, + struct ww_acquire_ctx *ww_ctx) +{ +} + +static inline int __ww_mutex_check_kill(struct rt_mutex *lock, + struct rt_mutex_waiter *waiter, + struct ww_acquire_ctx *ww_ctx) +{ + return 0; +} + +#else +# define build_ww_mutex() (true) +# define ww_container_of(rtm) container_of(rtm, struct ww_mutex, base) +# include "ww_mutex.h" +#endif + /* * lock->owner state tracking: * @@ -50,7 +88,7 @@ */ static __always_inline void -rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner) +rt_mutex_set_owner(struct rt_mutex_base *lock, struct task_struct *owner) { unsigned long val = (unsigned long)owner; @@ -60,13 +98,13 @@ rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner) WRITE_ONCE(lock->owner, (struct task_struct *)val); } -static __always_inline void clear_rt_mutex_waiters(struct rt_mutex *lock) +static __always_inline void clear_rt_mutex_waiters(struct rt_mutex_base *lock) { lock->owner = (struct task_struct *) ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); } -static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock) +static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex_base *lock) { unsigned long owner, *p = (unsigned long *) &lock->owner; @@ -141,15 +179,26 @@ static __always_inline void fixup_rt_mutex_waiters(struct rt_mutex *lock) * set up. */ #ifndef CONFIG_DEBUG_RT_MUTEXES -# define rt_mutex_cmpxchg_acquire(l,c,n) (cmpxchg_acquire(&l->owner, c, n) == c) -# define rt_mutex_cmpxchg_release(l,c,n) (cmpxchg_release(&l->owner, c, n) == c) +static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +{ + return try_cmpxchg_acquire(&lock->owner, &old, new); +} + +static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +{ + return try_cmpxchg_release(&lock->owner, &old, new); +} /* * Callers must hold the ->wait_lock -- which is the whole purpose as we force * all future threads that attempt to [Rmw] the lock to the slowpath. As such * relaxed semantics suffice. */ -static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock) { unsigned long owner, *p = (unsigned long *) &lock->owner; @@ -165,7 +214,7 @@ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock) * 2) Drop lock->wait_lock * 3) Try to unlock the lock with cmpxchg */ -static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock, +static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock, unsigned long flags) __releases(lock->wait_lock) { @@ -201,10 +250,22 @@ static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock, } #else -# define rt_mutex_cmpxchg_acquire(l,c,n) (0) -# define rt_mutex_cmpxchg_release(l,c,n) (0) +static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +{ + return false; + +} -static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock) +static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock, + struct task_struct *old, + struct task_struct *new) +{ + return false; +} + +static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock) { lock->owner = (struct task_struct *) ((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); @@ -213,7 +274,7 @@ static __always_inline void mark_rt_mutex_waiters(struct rt_mutex *lock) /* * Simple slow path only version: lock->owner is protected by lock->wait_lock. */ -static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock, +static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock, unsigned long flags) __releases(lock->wait_lock) { @@ -223,11 +284,28 @@ static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex *lock, } #endif +static __always_inline int __waiter_prio(struct task_struct *task) +{ + int prio = task->prio; + + if (!rt_prio(prio)) + return DEFAULT_PRIO; + + return prio; +} + +static __always_inline void +waiter_update_prio(struct rt_mutex_waiter *waiter, struct task_struct *task) +{ + waiter->prio = __waiter_prio(task); + waiter->deadline = task->dl.deadline; +} + /* * Only use with rt_mutex_waiter_{less,equal}() */ #define task_to_waiter(p) \ - &(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline } + &(struct rt_mutex_waiter){ .prio = __waiter_prio(p), .deadline = (p)->dl.deadline } static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left, struct rt_mutex_waiter *right) @@ -265,22 +343,63 @@ static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left, return 1; } +static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter, + struct rt_mutex_waiter *top_waiter) +{ + if (rt_mutex_waiter_less(waiter, top_waiter)) + return true; + +#ifdef RT_MUTEX_BUILD_SPINLOCKS + /* + * Note that RT tasks are excluded from same priority (lateral) + * steals to prevent the introduction of an unbounded latency. + */ + if (rt_prio(waiter->prio) || dl_prio(waiter->prio)) + return false; + + return rt_mutex_waiter_equal(waiter, top_waiter); +#else + return false; +#endif +} + #define __node_2_waiter(node) \ rb_entry((node), struct rt_mutex_waiter, tree_entry) static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b) { - return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b)); + struct rt_mutex_waiter *aw = __node_2_waiter(a); + struct rt_mutex_waiter *bw = __node_2_waiter(b); + + if (rt_mutex_waiter_less(aw, bw)) + return 1; + + if (!build_ww_mutex()) + return 0; + + if (rt_mutex_waiter_less(bw, aw)) + return 0; + + /* NOTE: relies on waiter->ww_ctx being set before insertion */ + if (aw->ww_ctx) { + if (!bw->ww_ctx) + return 1; + + return (signed long)(aw->ww_ctx->stamp - + bw->ww_ctx->stamp) < 0; + } + + return 0; } static __always_inline void -rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) +rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter) { rb_add_cached(&waiter->tree_entry, &lock->waiters, __waiter_less); } static __always_inline void -rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) +rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter) { if (RB_EMPTY_NODE(&waiter->tree_entry)) return; @@ -326,6 +445,35 @@ static __always_inline void rt_mutex_adjust_prio(struct task_struct *p) rt_mutex_setprio(p, pi_task); } +/* RT mutex specific wake_q wrappers */ +static __always_inline void rt_mutex_wake_q_add(struct rt_wake_q_head *wqh, + struct rt_mutex_waiter *w) +{ + if (IS_ENABLED(CONFIG_PREEMPT_RT) && w->wake_state != TASK_NORMAL) { + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) + WARN_ON_ONCE(wqh->rtlock_task); + get_task_struct(w->task); + wqh->rtlock_task = w->task; + } else { + wake_q_add(&wqh->head, w->task); + } +} + +static __always_inline void rt_mutex_wake_up_q(struct rt_wake_q_head *wqh) +{ + if (IS_ENABLED(CONFIG_PREEMPT_RT) && wqh->rtlock_task) { + wake_up_state(wqh->rtlock_task, TASK_RTLOCK_WAIT); + put_task_struct(wqh->rtlock_task); + wqh->rtlock_task = NULL; + } + + if (!wake_q_empty(&wqh->head)) + wake_up_q(&wqh->head); + + /* Pairs with preempt_disable() in mark_wakeup_next_waiter() */ + preempt_enable(); +} + /* * Deadlock detection is conditional: * @@ -348,12 +496,7 @@ rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter, return chwalk == RT_MUTEX_FULL_CHAINWALK; } -/* - * Max number of times we'll walk the boosting chain: - */ -int max_lock_depth = 1024; - -static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p) +static __always_inline struct rt_mutex_base *task_blocked_on_lock(struct task_struct *p) { return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL; } @@ -423,15 +566,15 @@ static __always_inline struct rt_mutex *task_blocked_on_lock(struct task_struct */ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, enum rtmutex_chainwalk chwalk, - struct rt_mutex *orig_lock, - struct rt_mutex *next_lock, + struct rt_mutex_base *orig_lock, + struct rt_mutex_base *next_lock, struct rt_mutex_waiter *orig_waiter, struct task_struct *top_task) { struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; struct rt_mutex_waiter *prerequeue_top_waiter; int ret = 0, depth = 0; - struct rt_mutex *lock; + struct rt_mutex_base *lock; bool detect_deadlock; bool requeue = true; @@ -514,6 +657,31 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, goto out_unlock_pi; /* + * There could be 'spurious' loops in the lock graph due to ww_mutex, + * consider: + * + * P1: A, ww_A, ww_B + * P2: ww_B, ww_A + * P3: A + * + * P3 should not return -EDEADLK because it gets trapped in the cycle + * created by P1 and P2 (which will resolve -- and runs into + * max_lock_depth above). Therefore disable detect_deadlock such that + * the below termination condition can trigger once all relevant tasks + * are boosted. + * + * Even when we start with ww_mutex we can disable deadlock detection, + * since we would supress a ww_mutex induced deadlock at [6] anyway. + * Supressing it here however is not sufficient since we might still + * hit [6] due to adjustment driven iteration. + * + * NOTE: if someone were to create a deadlock between 2 ww_classes we'd + * utterly fail to report it; lockdep should. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT) && waiter->ww_ctx && detect_deadlock) + detect_deadlock = false; + + /* * Drop out, when the task has no waiters. Note, * top_waiter can be NULL, when we are in the deboosting * mode! @@ -574,8 +742,21 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, * walk, we detected a deadlock. */ if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { - raw_spin_unlock(&lock->wait_lock); ret = -EDEADLK; + + /* + * When the deadlock is due to ww_mutex; also see above. Don't + * report the deadlock and instead let the ww_mutex wound/die + * logic pick which of the contending threads gets -EDEADLK. + * + * NOTE: assumes the cycle only contains a single ww_class; any + * other configuration and we fail to report; also, see + * lockdep. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT) && orig_waiter && orig_waiter->ww_ctx) + ret = 0; + + raw_spin_unlock(&lock->wait_lock); goto out_unlock_pi; } @@ -653,8 +834,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, * serializes all pi_waiters access and rb_erase() does not care about * the values of the node being removed. */ - waiter->prio = task->prio; - waiter->deadline = task->dl.deadline; + waiter_update_prio(waiter, task); rt_mutex_enqueue(lock, waiter); @@ -676,7 +856,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, * to get the lock. */ if (prerequeue_top_waiter != rt_mutex_top_waiter(lock)) - wake_up_process(rt_mutex_top_waiter(lock)->task); + wake_up_state(waiter->task, waiter->wake_state); raw_spin_unlock_irq(&lock->wait_lock); return 0; } @@ -779,7 +959,7 @@ static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task, * callsite called task_blocked_on_lock(), otherwise NULL */ static int __sched -try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, +try_to_take_rt_mutex(struct rt_mutex_base *lock, struct task_struct *task, struct rt_mutex_waiter *waiter) { lockdep_assert_held(&lock->wait_lock); @@ -815,19 +995,21 @@ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, * trylock attempt. */ if (waiter) { - /* - * If waiter is not the highest priority waiter of - * @lock, give up. - */ - if (waiter != rt_mutex_top_waiter(lock)) - return 0; + struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock); /* - * We can acquire the lock. Remove the waiter from the - * lock waiters tree. + * If waiter is the highest priority waiter of @lock, + * or allowed to steal it, take it over. */ - rt_mutex_dequeue(lock, waiter); - + if (waiter == top_waiter || rt_mutex_steal(waiter, top_waiter)) { + /* + * We can acquire the lock. Remove the waiter from the + * lock waiters tree. + */ + rt_mutex_dequeue(lock, waiter); + } else { + return 0; + } } else { /* * If the lock has waiters already we check whether @task is @@ -838,13 +1020,9 @@ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, * not need to be dequeued. */ if (rt_mutex_has_waiters(lock)) { - /* - * If @task->prio is greater than or equal to - * the top waiter priority (kernel view), - * @task lost. - */ - if (!rt_mutex_waiter_less(task_to_waiter(task), - rt_mutex_top_waiter(lock))) + /* Check whether the trylock can steal it. */ + if (!rt_mutex_steal(task_to_waiter(task), + rt_mutex_top_waiter(lock))) return 0; /* @@ -897,14 +1075,15 @@ takeit: * * This must be called with lock->wait_lock held and interrupts disabled */ -static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock, +static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter, struct task_struct *task, + struct ww_acquire_ctx *ww_ctx, enum rtmutex_chainwalk chwalk) { struct task_struct *owner = rt_mutex_owner(lock); struct rt_mutex_waiter *top_waiter = waiter; - struct rt_mutex *next_lock; + struct rt_mutex_base *next_lock; int chain_walk = 0, res; lockdep_assert_held(&lock->wait_lock); @@ -918,14 +1097,31 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock, * which is wrong, as the other waiter is not in a deadlock * situation. */ - if (owner == task) + if (owner == task) { +#if defined(DEBUG_WW_MUTEXES) && defined(CONFIG_DEBUG_LOCKING_API_SELFTESTS) + /* + * The lockdep selftest for ww-mutex assumes in a few cases + * the ww_ctx->contending_lock assignment via + * __ww_mutex_check_kill() which does not happen if the rtmutex + * detects the deadlock early. + */ + if (build_ww_mutex() && ww_ctx) { + struct rt_mutex *rtm; + + /* Check whether the waiter should backout immediately */ + rtm = container_of(lock, struct rt_mutex, rtmutex); + + __ww_mutex_add_waiter(waiter, rtm, ww_ctx); + __ww_mutex_check_kill(rtm, waiter, ww_ctx); + } +#endif return -EDEADLK; + } raw_spin_lock(&task->pi_lock); waiter->task = task; waiter->lock = lock; - waiter->prio = task->prio; - waiter->deadline = task->dl.deadline; + waiter_update_prio(waiter, task); /* Get the top priority waiter on the lock */ if (rt_mutex_has_waiters(lock)) @@ -936,6 +1132,21 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock, raw_spin_unlock(&task->pi_lock); + if (build_ww_mutex() && ww_ctx) { + struct rt_mutex *rtm; + + /* Check whether the waiter should back out immediately */ + rtm = container_of(lock, struct rt_mutex, rtmutex); + res = __ww_mutex_add_waiter(waiter, rtm, ww_ctx); + if (res) { + raw_spin_lock(&task->pi_lock); + rt_mutex_dequeue(lock, waiter); + task->pi_blocked_on = NULL; + raw_spin_unlock(&task->pi_lock); + return res; + } + } + if (!owner) return 0; @@ -986,8 +1197,8 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex *lock, * * Called with lock->wait_lock held and interrupts disabled. */ -static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q, - struct rt_mutex *lock) +static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh, + struct rt_mutex_base *lock) { struct rt_mutex_waiter *waiter; @@ -1023,235 +1234,14 @@ static void __sched mark_wakeup_next_waiter(struct wake_q_head *wake_q, * deboost but before waking our donor task, hence the preempt_disable() * before unlock. * - * Pairs with preempt_enable() in rt_mutex_postunlock(); + * Pairs with preempt_enable() in rt_mutex_wake_up_q(); */ preempt_disable(); - wake_q_add(wake_q, waiter->task); - raw_spin_unlock(¤t->pi_lock); -} - -/* - * Remove a waiter from a lock and give up - * - * Must be called with lock->wait_lock held and interrupts disabled. I must - * have just failed to try_to_take_rt_mutex(). - */ -static void __sched remove_waiter(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter) -{ - bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock)); - struct task_struct *owner = rt_mutex_owner(lock); - struct rt_mutex *next_lock; - - lockdep_assert_held(&lock->wait_lock); - - raw_spin_lock(¤t->pi_lock); - rt_mutex_dequeue(lock, waiter); - current->pi_blocked_on = NULL; + rt_mutex_wake_q_add(wqh, waiter); raw_spin_unlock(¤t->pi_lock); - - /* - * Only update priority if the waiter was the highest priority - * waiter of the lock and there is an owner to update. - */ - if (!owner || !is_top_waiter) - return; - - raw_spin_lock(&owner->pi_lock); - - rt_mutex_dequeue_pi(owner, waiter); - - if (rt_mutex_has_waiters(lock)) - rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock)); - - rt_mutex_adjust_prio(owner); - - /* Store the lock on which owner is blocked or NULL */ - next_lock = task_blocked_on_lock(owner); - - raw_spin_unlock(&owner->pi_lock); - - /* - * Don't walk the chain, if the owner task is not blocked - * itself. - */ - if (!next_lock) - return; - - /* gets dropped in rt_mutex_adjust_prio_chain()! */ - get_task_struct(owner); - - raw_spin_unlock_irq(&lock->wait_lock); - - rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock, - next_lock, NULL, current); - - raw_spin_lock_irq(&lock->wait_lock); -} - -/* - * Recheck the pi chain, in case we got a priority setting - * - * Called from sched_setscheduler - */ -void __sched rt_mutex_adjust_pi(struct task_struct *task) -{ - struct rt_mutex_waiter *waiter; - struct rt_mutex *next_lock; - unsigned long flags; - - raw_spin_lock_irqsave(&task->pi_lock, flags); - - waiter = task->pi_blocked_on; - if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { - raw_spin_unlock_irqrestore(&task->pi_lock, flags); - return; - } - next_lock = waiter->lock; - raw_spin_unlock_irqrestore(&task->pi_lock, flags); - - /* gets dropped in rt_mutex_adjust_prio_chain()! */ - get_task_struct(task); - - rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL, - next_lock, NULL, task); -} - -void __sched rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) -{ - debug_rt_mutex_init_waiter(waiter); - RB_CLEAR_NODE(&waiter->pi_tree_entry); - RB_CLEAR_NODE(&waiter->tree_entry); - waiter->task = NULL; -} - -/** - * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop - * @lock: the rt_mutex to take - * @state: the state the task should block in (TASK_INTERRUPTIBLE - * or TASK_UNINTERRUPTIBLE) - * @timeout: the pre-initialized and started timer, or NULL for none - * @waiter: the pre-initialized rt_mutex_waiter - * - * Must be called with lock->wait_lock held and interrupts disabled - */ -static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state, - struct hrtimer_sleeper *timeout, - struct rt_mutex_waiter *waiter) -{ - int ret = 0; - - for (;;) { - /* Try to acquire the lock: */ - if (try_to_take_rt_mutex(lock, current, waiter)) - break; - - if (timeout && !timeout->task) { - ret = -ETIMEDOUT; - break; - } - if (signal_pending_state(state, current)) { - ret = -EINTR; - break; - } - - raw_spin_unlock_irq(&lock->wait_lock); - - schedule(); - - raw_spin_lock_irq(&lock->wait_lock); - set_current_state(state); - } - - __set_current_state(TASK_RUNNING); - return ret; -} - -static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, - struct rt_mutex_waiter *w) -{ - /* - * If the result is not -EDEADLOCK or the caller requested - * deadlock detection, nothing to do here. - */ - if (res != -EDEADLOCK || detect_deadlock) - return; - - /* - * Yell loudly and stop the task right here. - */ - WARN(1, "rtmutex deadlock detected\n"); - while (1) { - set_current_state(TASK_INTERRUPTIBLE); - schedule(); - } -} - -/* - * Slow path lock function: - */ -static int __sched rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state, - struct hrtimer_sleeper *timeout, - enum rtmutex_chainwalk chwalk) -{ - struct rt_mutex_waiter waiter; - unsigned long flags; - int ret = 0; - - rt_mutex_init_waiter(&waiter); - - /* - * Technically we could use raw_spin_[un]lock_irq() here, but this can - * be called in early boot if the cmpxchg() fast path is disabled - * (debug, no architecture support). In this case we will acquire the - * rtmutex with lock->wait_lock held. But we cannot unconditionally - * enable interrupts in that early boot case. So we need to use the - * irqsave/restore variants. - */ - raw_spin_lock_irqsave(&lock->wait_lock, flags); - - /* Try to acquire the lock again: */ - if (try_to_take_rt_mutex(lock, current, NULL)) { - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - return 0; - } - - set_current_state(state); - - /* Setup the timer, when timeout != NULL */ - if (unlikely(timeout)) - hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); - - ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk); - - if (likely(!ret)) - /* sleep on the mutex */ - ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); - - if (unlikely(ret)) { - __set_current_state(TASK_RUNNING); - remove_waiter(lock, &waiter); - rt_mutex_handle_deadlock(ret, chwalk, &waiter); - } - - /* - * try_to_take_rt_mutex() sets the waiter bit - * unconditionally. We might have to fix that up. - */ - fixup_rt_mutex_waiters(lock); - - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - - /* Remove pending timer: */ - if (unlikely(timeout)) - hrtimer_cancel(&timeout->timer); - - debug_rt_mutex_free_waiter(&waiter); - - return ret; } -static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock) +static int __sched __rt_mutex_slowtrylock(struct rt_mutex_base *lock) { int ret = try_to_take_rt_mutex(lock, current, NULL); @@ -1267,7 +1257,7 @@ static int __sched __rt_mutex_slowtrylock(struct rt_mutex *lock) /* * Slow path try-lock function: */ -static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock) +static int __sched rt_mutex_slowtrylock(struct rt_mutex_base *lock) { unsigned long flags; int ret; @@ -1293,25 +1283,20 @@ static int __sched rt_mutex_slowtrylock(struct rt_mutex *lock) return ret; } -/* - * Performs the wakeup of the top-waiter and re-enables preemption. - */ -void __sched rt_mutex_postunlock(struct wake_q_head *wake_q) +static __always_inline int __rt_mutex_trylock(struct rt_mutex_base *lock) { - wake_up_q(wake_q); + if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) + return 1; - /* Pairs with preempt_disable() in mark_wakeup_next_waiter() */ - preempt_enable(); + return rt_mutex_slowtrylock(lock); } /* * Slow path to release a rt-mutex. - * - * Return whether the current task needs to call rt_mutex_postunlock(). */ -static void __sched rt_mutex_slowunlock(struct rt_mutex *lock) +static void __sched rt_mutex_slowunlock(struct rt_mutex_base *lock) { - DEFINE_WAKE_Q(wake_q); + DEFINE_RT_WAKE_Q(wqh); unsigned long flags; /* irqsave required to support early boot calls */ @@ -1364,422 +1349,387 @@ static void __sched rt_mutex_slowunlock(struct rt_mutex *lock) * * Queue the next waiter for wakeup once we release the wait_lock. */ - mark_wakeup_next_waiter(&wake_q, lock); + mark_wakeup_next_waiter(&wqh, lock); raw_spin_unlock_irqrestore(&lock->wait_lock, flags); - rt_mutex_postunlock(&wake_q); + rt_mutex_wake_up_q(&wqh); } -/* - * debug aware fast / slowpath lock,trylock,unlock - * - * The atomic acquire/release ops are compiled away, when either the - * architecture does not support cmpxchg or when debugging is enabled. - */ -static __always_inline int __rt_mutex_lock(struct rt_mutex *lock, long state, - unsigned int subclass) +static __always_inline void __rt_mutex_unlock(struct rt_mutex_base *lock) { - int ret; - - might_sleep(); - mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_); - - if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) - return 0; + if (likely(rt_mutex_cmpxchg_release(lock, current, NULL))) + return; - ret = rt_mutex_slowlock(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK); - if (ret) - mutex_release(&lock->dep_map, _RET_IP_); - return ret; + rt_mutex_slowunlock(lock); } -#ifdef CONFIG_DEBUG_LOCK_ALLOC -/** - * rt_mutex_lock_nested - lock a rt_mutex - * - * @lock: the rt_mutex to be locked - * @subclass: the lockdep subclass - */ -void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass) +#ifdef CONFIG_SMP +static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *owner) { - __rt_mutex_lock(lock, TASK_UNINTERRUPTIBLE, subclass); -} -EXPORT_SYMBOL_GPL(rt_mutex_lock_nested); + bool res = true; -#else /* !CONFIG_DEBUG_LOCK_ALLOC */ - -/** - * rt_mutex_lock - lock a rt_mutex - * - * @lock: the rt_mutex to be locked - */ -void __sched rt_mutex_lock(struct rt_mutex *lock) + rcu_read_lock(); + for (;;) { + /* If owner changed, trylock again. */ + if (owner != rt_mutex_owner(lock)) + break; + /* + * Ensure that @owner is dereferenced after checking that + * the lock owner still matches @owner. If that fails, + * @owner might point to freed memory. If it still matches, + * the rcu_read_lock() ensures the memory stays valid. + */ + barrier(); + /* + * Stop spinning when: + * - the lock owner has been scheduled out + * - current is not longer the top waiter + * - current is requested to reschedule (redundant + * for CONFIG_PREEMPT_RCU=y) + * - the VCPU on which owner runs is preempted + */ + if (!owner->on_cpu || need_resched() || + rt_mutex_waiter_is_top_waiter(lock, waiter) || + vcpu_is_preempted(task_cpu(owner))) { + res = false; + break; + } + cpu_relax(); + } + rcu_read_unlock(); + return res; +} +#else +static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *owner) { - __rt_mutex_lock(lock, TASK_UNINTERRUPTIBLE, 0); + return false; } -EXPORT_SYMBOL_GPL(rt_mutex_lock); #endif -/** - * rt_mutex_lock_interruptible - lock a rt_mutex interruptible - * - * @lock: the rt_mutex to be locked - * - * Returns: - * 0 on success - * -EINTR when interrupted by a signal +#ifdef RT_MUTEX_BUILD_MUTEX +/* + * Functions required for: + * - rtmutex, futex on all kernels + * - mutex and rwsem substitutions on RT kernels */ -int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock) -{ - return __rt_mutex_lock(lock, TASK_INTERRUPTIBLE, 0); -} -EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); -/** - * rt_mutex_trylock - try to lock a rt_mutex - * - * @lock: the rt_mutex to be locked - * - * This function can only be called in thread context. It's safe to call it - * from atomic regions, but not from hard or soft interrupt context. +/* + * Remove a waiter from a lock and give up * - * Returns: - * 1 on success - * 0 on contention + * Must be called with lock->wait_lock held and interrupts disabled. It must + * have just failed to try_to_take_rt_mutex(). */ -int __sched rt_mutex_trylock(struct rt_mutex *lock) +static void __sched remove_waiter(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter) { - int ret; + bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock)); + struct task_struct *owner = rt_mutex_owner(lock); + struct rt_mutex_base *next_lock; - if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task())) - return 0; + lockdep_assert_held(&lock->wait_lock); + + raw_spin_lock(¤t->pi_lock); + rt_mutex_dequeue(lock, waiter); + current->pi_blocked_on = NULL; + raw_spin_unlock(¤t->pi_lock); /* - * No lockdep annotation required because lockdep disables the fast - * path. + * Only update priority if the waiter was the highest priority + * waiter of the lock and there is an owner to update. */ - if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) - return 1; - - ret = rt_mutex_slowtrylock(lock); - if (ret) - mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_); - - return ret; -} -EXPORT_SYMBOL_GPL(rt_mutex_trylock); - -/** - * rt_mutex_unlock - unlock a rt_mutex - * - * @lock: the rt_mutex to be unlocked - */ -void __sched rt_mutex_unlock(struct rt_mutex *lock) -{ - mutex_release(&lock->dep_map, _RET_IP_); - if (likely(rt_mutex_cmpxchg_release(lock, current, NULL))) + if (!owner || !is_top_waiter) return; - rt_mutex_slowunlock(lock); -} -EXPORT_SYMBOL_GPL(rt_mutex_unlock); + raw_spin_lock(&owner->pi_lock); -/* - * Futex variants, must not use fastpath. - */ -int __sched rt_mutex_futex_trylock(struct rt_mutex *lock) -{ - return rt_mutex_slowtrylock(lock); -} + rt_mutex_dequeue_pi(owner, waiter); -int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock) -{ - return __rt_mutex_slowtrylock(lock); -} + if (rt_mutex_has_waiters(lock)) + rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock)); -/** - * __rt_mutex_futex_unlock - Futex variant, that since futex variants - * do not use the fast-path, can be simple and will not need to retry. - * - * @lock: The rt_mutex to be unlocked - * @wake_q: The wake queue head from which to get the next lock waiter - */ -bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock, - struct wake_q_head *wake_q) -{ - lockdep_assert_held(&lock->wait_lock); + rt_mutex_adjust_prio(owner); - debug_rt_mutex_unlock(lock); + /* Store the lock on which owner is blocked or NULL */ + next_lock = task_blocked_on_lock(owner); - if (!rt_mutex_has_waiters(lock)) { - lock->owner = NULL; - return false; /* done */ - } + raw_spin_unlock(&owner->pi_lock); /* - * We've already deboosted, mark_wakeup_next_waiter() will - * retain preempt_disabled when we drop the wait_lock, to - * avoid inversion prior to the wakeup. preempt_disable() - * therein pairs with rt_mutex_postunlock(). + * Don't walk the chain, if the owner task is not blocked + * itself. */ - mark_wakeup_next_waiter(wake_q, lock); + if (!next_lock) + return; - return true; /* call postunlock() */ -} + /* gets dropped in rt_mutex_adjust_prio_chain()! */ + get_task_struct(owner); -void __sched rt_mutex_futex_unlock(struct rt_mutex *lock) -{ - DEFINE_WAKE_Q(wake_q); - unsigned long flags; - bool postunlock; + raw_spin_unlock_irq(&lock->wait_lock); - raw_spin_lock_irqsave(&lock->wait_lock, flags); - postunlock = __rt_mutex_futex_unlock(lock, &wake_q); - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); + rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock, + next_lock, NULL, current); - if (postunlock) - rt_mutex_postunlock(&wake_q); + raw_spin_lock_irq(&lock->wait_lock); } /** - * __rt_mutex_init - initialize the rt_mutex - * - * @lock: The rt_mutex to be initialized - * @name: The lock name used for debugging - * @key: The lock class key used for debugging - * - * Initialize the rt_mutex to unlocked state. + * rt_mutex_slowlock_block() - Perform the wait-wake-try-to-take loop + * @lock: the rt_mutex to take + * @ww_ctx: WW mutex context pointer + * @state: the state the task should block in (TASK_INTERRUPTIBLE + * or TASK_UNINTERRUPTIBLE) + * @timeout: the pre-initialized and started timer, or NULL for none + * @waiter: the pre-initialized rt_mutex_waiter * - * Initializing of a locked rt_mutex is not allowed + * Must be called with lock->wait_lock held and interrupts disabled */ -void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name, - struct lock_class_key *key) +static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock, + struct ww_acquire_ctx *ww_ctx, + unsigned int state, + struct hrtimer_sleeper *timeout, + struct rt_mutex_waiter *waiter) { - debug_check_no_locks_freed((void *)lock, sizeof(*lock)); - lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP); + struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex); + struct task_struct *owner; + int ret = 0; - __rt_mutex_basic_init(lock); -} -EXPORT_SYMBOL_GPL(__rt_mutex_init); + for (;;) { + /* Try to acquire the lock: */ + if (try_to_take_rt_mutex(lock, current, waiter)) + break; -/** - * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a - * proxy owner - * - * @lock: the rt_mutex to be locked - * @proxy_owner:the task to set as owner - * - * No locking. Caller has to do serializing itself - * - * Special API call for PI-futex support. This initializes the rtmutex and - * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not - * possible at this point because the pi_state which contains the rtmutex - * is not yet visible to other tasks. - */ -void __sched rt_mutex_init_proxy_locked(struct rt_mutex *lock, - struct task_struct *proxy_owner) -{ - __rt_mutex_basic_init(lock); - rt_mutex_set_owner(lock, proxy_owner); + if (timeout && !timeout->task) { + ret = -ETIMEDOUT; + break; + } + if (signal_pending_state(state, current)) { + ret = -EINTR; + break; + } + + if (build_ww_mutex() && ww_ctx) { + ret = __ww_mutex_check_kill(rtm, waiter, ww_ctx); + if (ret) + break; + } + + if (waiter == rt_mutex_top_waiter(lock)) + owner = rt_mutex_owner(lock); + else + owner = NULL; + raw_spin_unlock_irq(&lock->wait_lock); + + if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner)) + schedule(); + + raw_spin_lock_irq(&lock->wait_lock); + set_current_state(state); + } + + __set_current_state(TASK_RUNNING); + return ret; } -/** - * rt_mutex_proxy_unlock - release a lock on behalf of owner - * - * @lock: the rt_mutex to be locked - * - * No locking. Caller has to do serializing itself - * - * Special API call for PI-futex support. This merrily cleans up the rtmutex - * (debugging) state. Concurrent operations on this rt_mutex are not - * possible because it belongs to the pi_state which is about to be freed - * and it is not longer visible to other tasks. - */ -void __sched rt_mutex_proxy_unlock(struct rt_mutex *lock) +static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex_waiter *w) { - debug_rt_mutex_proxy_unlock(lock); - rt_mutex_set_owner(lock, NULL); + /* + * If the result is not -EDEADLOCK or the caller requested + * deadlock detection, nothing to do here. + */ + if (res != -EDEADLOCK || detect_deadlock) + return; + + if (build_ww_mutex() && w->ww_ctx) + return; + + /* + * Yell loudly and stop the task right here. + */ + WARN(1, "rtmutex deadlock detected\n"); + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + schedule(); + } } /** - * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task - * @lock: the rt_mutex to take - * @waiter: the pre-initialized rt_mutex_waiter - * @task: the task to prepare - * - * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock - * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that. - * - * NOTE: does _NOT_ remove the @waiter on failure; must either call - * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this. - * - * Returns: - * 0 - task blocked on lock - * 1 - acquired the lock for task, caller should wake it up - * <0 - error - * - * Special API call for PI-futex support. + * __rt_mutex_slowlock - Locking slowpath invoked with lock::wait_lock held + * @lock: The rtmutex to block lock + * @ww_ctx: WW mutex context pointer + * @state: The task state for sleeping + * @chwalk: Indicator whether full or partial chainwalk is requested + * @waiter: Initializer waiter for blocking */ -int __sched __rt_mutex_start_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter, - struct task_struct *task) +static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, + struct ww_acquire_ctx *ww_ctx, + unsigned int state, + enum rtmutex_chainwalk chwalk, + struct rt_mutex_waiter *waiter) { + struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex); + struct ww_mutex *ww = ww_container_of(rtm); int ret; lockdep_assert_held(&lock->wait_lock); - if (try_to_take_rt_mutex(lock, task, NULL)) - return 1; + /* Try to acquire the lock again: */ + if (try_to_take_rt_mutex(lock, current, NULL)) { + if (build_ww_mutex() && ww_ctx) { + __ww_mutex_check_waiters(rtm, ww_ctx); + ww_mutex_lock_acquired(ww, ww_ctx); + } + return 0; + } - /* We enforce deadlock detection for futexes */ - ret = task_blocks_on_rt_mutex(lock, waiter, task, - RT_MUTEX_FULL_CHAINWALK); + set_current_state(state); - if (ret && !rt_mutex_owner(lock)) { - /* - * Reset the return value. We might have - * returned with -EDEADLK and the owner - * released the lock while we were walking the - * pi chain. Let the waiter sort it out. - */ - ret = 0; + ret = task_blocks_on_rt_mutex(lock, waiter, current, ww_ctx, chwalk); + if (likely(!ret)) + ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter); + + if (likely(!ret)) { + /* acquired the lock */ + if (build_ww_mutex() && ww_ctx) { + if (!ww_ctx->is_wait_die) + __ww_mutex_check_waiters(rtm, ww_ctx); + ww_mutex_lock_acquired(ww, ww_ctx); + } + } else { + __set_current_state(TASK_RUNNING); + remove_waiter(lock, waiter); + rt_mutex_handle_deadlock(ret, chwalk, waiter); } + /* + * try_to_take_rt_mutex() sets the waiter bit + * unconditionally. We might have to fix that up. + */ + fixup_rt_mutex_waiters(lock); return ret; } -/** - * rt_mutex_start_proxy_lock() - Start lock acquisition for another task - * @lock: the rt_mutex to take - * @waiter: the pre-initialized rt_mutex_waiter - * @task: the task to prepare - * - * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock - * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that. - * - * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter - * on failure. - * - * Returns: - * 0 - task blocked on lock - * 1 - acquired the lock for task, caller should wake it up - * <0 - error - * - * Special API call for PI-futex support. - */ -int __sched rt_mutex_start_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter, - struct task_struct *task) +static inline int __rt_mutex_slowlock_locked(struct rt_mutex_base *lock, + struct ww_acquire_ctx *ww_ctx, + unsigned int state) { + struct rt_mutex_waiter waiter; int ret; - raw_spin_lock_irq(&lock->wait_lock); - ret = __rt_mutex_start_proxy_lock(lock, waiter, task); - if (unlikely(ret)) - remove_waiter(lock, waiter); - raw_spin_unlock_irq(&lock->wait_lock); + rt_mutex_init_waiter(&waiter); + waiter.ww_ctx = ww_ctx; + + ret = __rt_mutex_slowlock(lock, ww_ctx, state, RT_MUTEX_MIN_CHAINWALK, + &waiter); + debug_rt_mutex_free_waiter(&waiter); return ret; } -/** - * rt_mutex_wait_proxy_lock() - Wait for lock acquisition - * @lock: the rt_mutex we were woken on - * @to: the timeout, null if none. hrtimer should already have - * been started. - * @waiter: the pre-initialized rt_mutex_waiter - * - * Wait for the lock acquisition started on our behalf by - * rt_mutex_start_proxy_lock(). Upon failure, the caller must call - * rt_mutex_cleanup_proxy_lock(). - * - * Returns: - * 0 - success - * <0 - error, one of -EINTR, -ETIMEDOUT - * - * Special API call for PI-futex support +/* + * rt_mutex_slowlock - Locking slowpath invoked when fast path fails + * @lock: The rtmutex to block lock + * @ww_ctx: WW mutex context pointer + * @state: The task state for sleeping */ -int __sched rt_mutex_wait_proxy_lock(struct rt_mutex *lock, - struct hrtimer_sleeper *to, - struct rt_mutex_waiter *waiter) +static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock, + struct ww_acquire_ctx *ww_ctx, + unsigned int state) { + unsigned long flags; int ret; - raw_spin_lock_irq(&lock->wait_lock); - /* sleep on the mutex */ - set_current_state(TASK_INTERRUPTIBLE); - ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); /* - * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might - * have to fix that up. + * Technically we could use raw_spin_[un]lock_irq() here, but this can + * be called in early boot if the cmpxchg() fast path is disabled + * (debug, no architecture support). In this case we will acquire the + * rtmutex with lock->wait_lock held. But we cannot unconditionally + * enable interrupts in that early boot case. So we need to use the + * irqsave/restore variants. */ - fixup_rt_mutex_waiters(lock); - raw_spin_unlock_irq(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); + ret = __rt_mutex_slowlock_locked(lock, ww_ctx, state); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); return ret; } +static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock, + unsigned int state) +{ + if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current))) + return 0; + + return rt_mutex_slowlock(lock, NULL, state); +} +#endif /* RT_MUTEX_BUILD_MUTEX */ + +#ifdef RT_MUTEX_BUILD_SPINLOCKS +/* + * Functions required for spin/rw_lock substitution on RT kernels + */ + /** - * rt_mutex_cleanup_proxy_lock() - Cleanup failed lock acquisition - * @lock: the rt_mutex we were woken on - * @waiter: the pre-initialized rt_mutex_waiter - * - * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or - * rt_mutex_wait_proxy_lock(). - * - * Unless we acquired the lock; we're still enqueued on the wait-list and can - * in fact still be granted ownership until we're removed. Therefore we can - * find we are in fact the owner and must disregard the - * rt_mutex_wait_proxy_lock() failure. - * - * Returns: - * true - did the cleanup, we done. - * false - we acquired the lock after rt_mutex_wait_proxy_lock() returned, - * caller should disregards its return value. - * - * Special API call for PI-futex support + * rtlock_slowlock_locked - Slow path lock acquisition for RT locks + * @lock: The underlying RT mutex */ -bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter) +static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock) { - bool cleanup = false; + struct rt_mutex_waiter waiter; + struct task_struct *owner; - raw_spin_lock_irq(&lock->wait_lock); - /* - * Do an unconditional try-lock, this deals with the lock stealing - * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter() - * sets a NULL owner. - * - * We're not interested in the return value, because the subsequent - * test on rt_mutex_owner() will infer that. If the trylock succeeded, - * we will own the lock and it will have removed the waiter. If we - * failed the trylock, we're still not owner and we need to remove - * ourselves. - */ - try_to_take_rt_mutex(lock, current, waiter); - /* - * Unless we're the owner; we're still enqueued on the wait_list. - * So check if we became owner, if not, take us off the wait_list. - */ - if (rt_mutex_owner(lock) != current) { - remove_waiter(lock, waiter); - cleanup = true; + lockdep_assert_held(&lock->wait_lock); + + if (try_to_take_rt_mutex(lock, current, NULL)) + return; + + rt_mutex_init_rtlock_waiter(&waiter); + + /* Save current state and set state to TASK_RTLOCK_WAIT */ + current_save_and_set_rtlock_wait_state(); + + task_blocks_on_rt_mutex(lock, &waiter, current, NULL, RT_MUTEX_MIN_CHAINWALK); + + for (;;) { + /* Try to acquire the lock again */ + if (try_to_take_rt_mutex(lock, current, &waiter)) + break; + + if (&waiter == rt_mutex_top_waiter(lock)) + owner = rt_mutex_owner(lock); + else + owner = NULL; + raw_spin_unlock_irq(&lock->wait_lock); + + if (!owner || !rtmutex_spin_on_owner(lock, &waiter, owner)) + schedule_rtlock(); + + raw_spin_lock_irq(&lock->wait_lock); + set_current_state(TASK_RTLOCK_WAIT); } + + /* Restore the task state */ + current_restore_rtlock_saved_state(); + /* - * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might - * have to fix that up. + * try_to_take_rt_mutex() sets the waiter bit unconditionally. + * We might have to fix that up: */ fixup_rt_mutex_waiters(lock); - - raw_spin_unlock_irq(&lock->wait_lock); - - return cleanup; + debug_rt_mutex_free_waiter(&waiter); } -#ifdef CONFIG_DEBUG_RT_MUTEXES -void rt_mutex_debug_task_free(struct task_struct *task) +static __always_inline void __sched rtlock_slowlock(struct rt_mutex_base *lock) { - DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); - DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); + unsigned long flags; + + raw_spin_lock_irqsave(&lock->wait_lock, flags); + rtlock_slowlock_locked(lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); } -#endif + +#endif /* RT_MUTEX_BUILD_SPINLOCKS */ diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c new file mode 100644 index 000000000000..900220941caa --- /dev/null +++ b/kernel/locking/rtmutex_api.c @@ -0,0 +1,612 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * rtmutex API + */ +#include <linux/spinlock.h> +#include <linux/export.h> + +#define RT_MUTEX_BUILD_MUTEX +#include "rtmutex.c" + +/* + * Max number of times we'll walk the boosting chain: + */ +int max_lock_depth = 1024; + +/* + * Debug aware fast / slowpath lock,trylock,unlock + * + * The atomic acquire/release ops are compiled away, when either the + * architecture does not support cmpxchg or when debugging is enabled. + */ +static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock, + unsigned int state, + struct lockdep_map *nest_lock, + unsigned int subclass) +{ + int ret; + + might_sleep(); + mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, _RET_IP_); + ret = __rt_mutex_lock(&lock->rtmutex, state); + if (ret) + mutex_release(&lock->dep_map, _RET_IP_); + return ret; +} + +void rt_mutex_base_init(struct rt_mutex_base *rtb) +{ + __rt_mutex_base_init(rtb); +} +EXPORT_SYMBOL(rt_mutex_base_init); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +/** + * rt_mutex_lock_nested - lock a rt_mutex + * + * @lock: the rt_mutex to be locked + * @subclass: the lockdep subclass + */ +void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass) +{ + __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass); +} +EXPORT_SYMBOL_GPL(rt_mutex_lock_nested); + +void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock) +{ + __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0); +} +EXPORT_SYMBOL_GPL(_rt_mutex_lock_nest_lock); + +#else /* !CONFIG_DEBUG_LOCK_ALLOC */ + +/** + * rt_mutex_lock - lock a rt_mutex + * + * @lock: the rt_mutex to be locked + */ +void __sched rt_mutex_lock(struct rt_mutex *lock) +{ + __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, 0); +} +EXPORT_SYMBOL_GPL(rt_mutex_lock); +#endif + +/** + * rt_mutex_lock_interruptible - lock a rt_mutex interruptible + * + * @lock: the rt_mutex to be locked + * + * Returns: + * 0 on success + * -EINTR when interrupted by a signal + */ +int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock) +{ + return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, NULL, 0); +} +EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); + +/** + * rt_mutex_lock_killable - lock a rt_mutex killable + * + * @lock: the rt_mutex to be locked + * + * Returns: + * 0 on success + * -EINTR when interrupted by a signal + */ +int __sched rt_mutex_lock_killable(struct rt_mutex *lock) +{ + return __rt_mutex_lock_common(lock, TASK_KILLABLE, NULL, 0); +} +EXPORT_SYMBOL_GPL(rt_mutex_lock_killable); + +/** + * rt_mutex_trylock - try to lock a rt_mutex + * + * @lock: the rt_mutex to be locked + * + * This function can only be called in thread context. It's safe to call it + * from atomic regions, but not from hard or soft interrupt context. + * + * Returns: + * 1 on success + * 0 on contention + */ +int __sched rt_mutex_trylock(struct rt_mutex *lock) +{ + int ret; + + if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task())) + return 0; + + ret = __rt_mutex_trylock(&lock->rtmutex); + if (ret) + mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_); + + return ret; +} +EXPORT_SYMBOL_GPL(rt_mutex_trylock); + +/** + * rt_mutex_unlock - unlock a rt_mutex + * + * @lock: the rt_mutex to be unlocked + */ +void __sched rt_mutex_unlock(struct rt_mutex *lock) +{ + mutex_release(&lock->dep_map, _RET_IP_); + __rt_mutex_unlock(&lock->rtmutex); +} +EXPORT_SYMBOL_GPL(rt_mutex_unlock); + +/* + * Futex variants, must not use fastpath. + */ +int __sched rt_mutex_futex_trylock(struct rt_mutex_base *lock) +{ + return rt_mutex_slowtrylock(lock); +} + +int __sched __rt_mutex_futex_trylock(struct rt_mutex_base *lock) +{ + return __rt_mutex_slowtrylock(lock); +} + +/** + * __rt_mutex_futex_unlock - Futex variant, that since futex variants + * do not use the fast-path, can be simple and will not need to retry. + * + * @lock: The rt_mutex to be unlocked + * @wqh: The wake queue head from which to get the next lock waiter + */ +bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock, + struct rt_wake_q_head *wqh) +{ + lockdep_assert_held(&lock->wait_lock); + + debug_rt_mutex_unlock(lock); + + if (!rt_mutex_has_waiters(lock)) { + lock->owner = NULL; + return false; /* done */ + } + + /* + * We've already deboosted, mark_wakeup_next_waiter() will + * retain preempt_disabled when we drop the wait_lock, to + * avoid inversion prior to the wakeup. preempt_disable() + * therein pairs with rt_mutex_postunlock(). + */ + mark_wakeup_next_waiter(wqh, lock); + + return true; /* call postunlock() */ +} + +void __sched rt_mutex_futex_unlock(struct rt_mutex_base *lock) +{ + DEFINE_RT_WAKE_Q(wqh); + unsigned long flags; + bool postunlock; + + raw_spin_lock_irqsave(&lock->wait_lock, flags); + postunlock = __rt_mutex_futex_unlock(lock, &wqh); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); + + if (postunlock) + rt_mutex_postunlock(&wqh); +} + +/** + * __rt_mutex_init - initialize the rt_mutex + * + * @lock: The rt_mutex to be initialized + * @name: The lock name used for debugging + * @key: The lock class key used for debugging + * + * Initialize the rt_mutex to unlocked state. + * + * Initializing of a locked rt_mutex is not allowed + */ +void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name, + struct lock_class_key *key) +{ + debug_check_no_locks_freed((void *)lock, sizeof(*lock)); + __rt_mutex_base_init(&lock->rtmutex); + lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP); +} +EXPORT_SYMBOL_GPL(__rt_mutex_init); + +/** + * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a + * proxy owner + * + * @lock: the rt_mutex to be locked + * @proxy_owner:the task to set as owner + * + * No locking. Caller has to do serializing itself + * + * Special API call for PI-futex support. This initializes the rtmutex and + * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not + * possible at this point because the pi_state which contains the rtmutex + * is not yet visible to other tasks. + */ +void __sched rt_mutex_init_proxy_locked(struct rt_mutex_base *lock, + struct task_struct *proxy_owner) +{ + static struct lock_class_key pi_futex_key; + + __rt_mutex_base_init(lock); + /* + * On PREEMPT_RT the futex hashbucket spinlock becomes 'sleeping' + * and rtmutex based. That causes a lockdep false positive, because + * some of the futex functions invoke spin_unlock(&hb->lock) with + * the wait_lock of the rtmutex associated to the pi_futex held. + * spin_unlock() in turn takes wait_lock of the rtmutex on which + * the spinlock is based, which makes lockdep notice a lock + * recursion. Give the futex/rtmutex wait_lock a separate key. + */ + lockdep_set_class(&lock->wait_lock, &pi_futex_key); + rt_mutex_set_owner(lock, proxy_owner); +} + +/** + * rt_mutex_proxy_unlock - release a lock on behalf of owner + * + * @lock: the rt_mutex to be locked + * + * No locking. Caller has to do serializing itself + * + * Special API call for PI-futex support. This just cleans up the rtmutex + * (debugging) state. Concurrent operations on this rt_mutex are not + * possible because it belongs to the pi_state which is about to be freed + * and it is not longer visible to other tasks. + */ +void __sched rt_mutex_proxy_unlock(struct rt_mutex_base *lock) +{ + debug_rt_mutex_proxy_unlock(lock); + rt_mutex_set_owner(lock, NULL); +} + +/** + * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task + * @lock: the rt_mutex to take + * @waiter: the pre-initialized rt_mutex_waiter + * @task: the task to prepare + * + * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock + * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that. + * + * NOTE: does _NOT_ remove the @waiter on failure; must either call + * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this. + * + * Returns: + * 0 - task blocked on lock + * 1 - acquired the lock for task, caller should wake it up + * <0 - error + * + * Special API call for PI-futex support. + */ +int __sched __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *task) +{ + int ret; + + lockdep_assert_held(&lock->wait_lock); + + if (try_to_take_rt_mutex(lock, task, NULL)) + return 1; + + /* We enforce deadlock detection for futexes */ + ret = task_blocks_on_rt_mutex(lock, waiter, task, NULL, + RT_MUTEX_FULL_CHAINWALK); + + if (ret && !rt_mutex_owner(lock)) { + /* + * Reset the return value. We might have + * returned with -EDEADLK and the owner + * released the lock while we were walking the + * pi chain. Let the waiter sort it out. + */ + ret = 0; + } + + return ret; +} + +/** + * rt_mutex_start_proxy_lock() - Start lock acquisition for another task + * @lock: the rt_mutex to take + * @waiter: the pre-initialized rt_mutex_waiter + * @task: the task to prepare + * + * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock + * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that. + * + * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter + * on failure. + * + * Returns: + * 0 - task blocked on lock + * 1 - acquired the lock for task, caller should wake it up + * <0 - error + * + * Special API call for PI-futex support. + */ +int __sched rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *task) +{ + int ret; + + raw_spin_lock_irq(&lock->wait_lock); + ret = __rt_mutex_start_proxy_lock(lock, waiter, task); + if (unlikely(ret)) + remove_waiter(lock, waiter); + raw_spin_unlock_irq(&lock->wait_lock); + + return ret; +} + +/** + * rt_mutex_wait_proxy_lock() - Wait for lock acquisition + * @lock: the rt_mutex we were woken on + * @to: the timeout, null if none. hrtimer should already have + * been started. + * @waiter: the pre-initialized rt_mutex_waiter + * + * Wait for the lock acquisition started on our behalf by + * rt_mutex_start_proxy_lock(). Upon failure, the caller must call + * rt_mutex_cleanup_proxy_lock(). + * + * Returns: + * 0 - success + * <0 - error, one of -EINTR, -ETIMEDOUT + * + * Special API call for PI-futex support + */ +int __sched rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock, + struct hrtimer_sleeper *to, + struct rt_mutex_waiter *waiter) +{ + int ret; + + raw_spin_lock_irq(&lock->wait_lock); + /* sleep on the mutex */ + set_current_state(TASK_INTERRUPTIBLE); + ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter); + /* + * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might + * have to fix that up. + */ + fixup_rt_mutex_waiters(lock); + raw_spin_unlock_irq(&lock->wait_lock); + + return ret; +} + +/** + * rt_mutex_cleanup_proxy_lock() - Cleanup failed lock acquisition + * @lock: the rt_mutex we were woken on + * @waiter: the pre-initialized rt_mutex_waiter + * + * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or + * rt_mutex_wait_proxy_lock(). + * + * Unless we acquired the lock; we're still enqueued on the wait-list and can + * in fact still be granted ownership until we're removed. Therefore we can + * find we are in fact the owner and must disregard the + * rt_mutex_wait_proxy_lock() failure. + * + * Returns: + * true - did the cleanup, we done. + * false - we acquired the lock after rt_mutex_wait_proxy_lock() returned, + * caller should disregards its return value. + * + * Special API call for PI-futex support + */ +bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter) +{ + bool cleanup = false; + + raw_spin_lock_irq(&lock->wait_lock); + /* + * Do an unconditional try-lock, this deals with the lock stealing + * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter() + * sets a NULL owner. + * + * We're not interested in the return value, because the subsequent + * test on rt_mutex_owner() will infer that. If the trylock succeeded, + * we will own the lock and it will have removed the waiter. If we + * failed the trylock, we're still not owner and we need to remove + * ourselves. + */ + try_to_take_rt_mutex(lock, current, waiter); + /* + * Unless we're the owner; we're still enqueued on the wait_list. + * So check if we became owner, if not, take us off the wait_list. + */ + if (rt_mutex_owner(lock) != current) { + remove_waiter(lock, waiter); + cleanup = true; + } + /* + * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might + * have to fix that up. + */ + fixup_rt_mutex_waiters(lock); + + raw_spin_unlock_irq(&lock->wait_lock); + + return cleanup; +} + +/* + * Recheck the pi chain, in case we got a priority setting + * + * Called from sched_setscheduler + */ +void __sched rt_mutex_adjust_pi(struct task_struct *task) +{ + struct rt_mutex_waiter *waiter; + struct rt_mutex_base *next_lock; + unsigned long flags; + + raw_spin_lock_irqsave(&task->pi_lock, flags); + + waiter = task->pi_blocked_on; + if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) { + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + return; + } + next_lock = waiter->lock; + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + + /* gets dropped in rt_mutex_adjust_prio_chain()! */ + get_task_struct(task); + + rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL, + next_lock, NULL, task); +} + +/* + * Performs the wakeup of the top-waiter and re-enables preemption. + */ +void __sched rt_mutex_postunlock(struct rt_wake_q_head *wqh) +{ + rt_mutex_wake_up_q(wqh); +} + +#ifdef CONFIG_DEBUG_RT_MUTEXES +void rt_mutex_debug_task_free(struct task_struct *task) +{ + DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); + DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); +} +#endif + +#ifdef CONFIG_PREEMPT_RT +/* Mutexes */ +void __mutex_rt_init(struct mutex *mutex, const char *name, + struct lock_class_key *key) +{ + debug_check_no_locks_freed((void *)mutex, sizeof(*mutex)); + lockdep_init_map_wait(&mutex->dep_map, name, key, 0, LD_WAIT_SLEEP); +} +EXPORT_SYMBOL(__mutex_rt_init); + +static __always_inline int __mutex_lock_common(struct mutex *lock, + unsigned int state, + unsigned int subclass, + struct lockdep_map *nest_lock, + unsigned long ip) +{ + int ret; + + might_sleep(); + mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip); + ret = __rt_mutex_lock(&lock->rtmutex, state); + if (ret) + mutex_release(&lock->dep_map, ip); + else + lock_acquired(&lock->dep_map, ip); + return ret; +} + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void __sched mutex_lock_nested(struct mutex *lock, unsigned int subclass) +{ + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_); +} +EXPORT_SYMBOL_GPL(mutex_lock_nested); + +void __sched _mutex_lock_nest_lock(struct mutex *lock, + struct lockdep_map *nest_lock) +{ + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, nest_lock, _RET_IP_); +} +EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock); + +int __sched mutex_lock_interruptible_nested(struct mutex *lock, + unsigned int subclass) +{ + return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, NULL, _RET_IP_); +} +EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); + +int __sched mutex_lock_killable_nested(struct mutex *lock, + unsigned int subclass) +{ + return __mutex_lock_common(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_); +} +EXPORT_SYMBOL_GPL(mutex_lock_killable_nested); + +void __sched mutex_lock_io_nested(struct mutex *lock, unsigned int subclass) +{ + int token; + + might_sleep(); + + token = io_schedule_prepare(); + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_); + io_schedule_finish(token); +} +EXPORT_SYMBOL_GPL(mutex_lock_io_nested); + +#else /* CONFIG_DEBUG_LOCK_ALLOC */ + +void __sched mutex_lock(struct mutex *lock) +{ + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_); +} +EXPORT_SYMBOL(mutex_lock); + +int __sched mutex_lock_interruptible(struct mutex *lock) +{ + return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, NULL, _RET_IP_); +} +EXPORT_SYMBOL(mutex_lock_interruptible); + +int __sched mutex_lock_killable(struct mutex *lock) +{ + return __mutex_lock_common(lock, TASK_KILLABLE, 0, NULL, _RET_IP_); +} +EXPORT_SYMBOL(mutex_lock_killable); + +void __sched mutex_lock_io(struct mutex *lock) +{ + int token = io_schedule_prepare(); + + __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_); + io_schedule_finish(token); +} +EXPORT_SYMBOL(mutex_lock_io); +#endif /* !CONFIG_DEBUG_LOCK_ALLOC */ + +int __sched mutex_trylock(struct mutex *lock) +{ + int ret; + + if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task())) + return 0; + + ret = __rt_mutex_trylock(&lock->rtmutex); + if (ret) + mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_); + + return ret; +} +EXPORT_SYMBOL(mutex_trylock); + +void __sched mutex_unlock(struct mutex *lock) +{ + mutex_release(&lock->dep_map, _RET_IP_); + __rt_mutex_unlock(&lock->rtmutex); +} +EXPORT_SYMBOL(mutex_unlock); + +#endif /* CONFIG_PREEMPT_RT */ diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index a90c22abdbca..c47e8361bfb5 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -25,29 +25,90 @@ * @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree * @task: task reference to the blocked task * @lock: Pointer to the rt_mutex on which the waiter blocks + * @wake_state: Wakeup state to use (TASK_NORMAL or TASK_RTLOCK_WAIT) * @prio: Priority of the waiter * @deadline: Deadline of the waiter if applicable + * @ww_ctx: WW context pointer */ struct rt_mutex_waiter { struct rb_node tree_entry; struct rb_node pi_tree_entry; struct task_struct *task; - struct rt_mutex *lock; + struct rt_mutex_base *lock; + unsigned int wake_state; int prio; u64 deadline; + struct ww_acquire_ctx *ww_ctx; }; +/** + * rt_wake_q_head - Wrapper around regular wake_q_head to support + * "sleeping" spinlocks on RT + * @head: The regular wake_q_head for sleeping lock variants + * @rtlock_task: Task pointer for RT lock (spin/rwlock) wakeups + */ +struct rt_wake_q_head { + struct wake_q_head head; + struct task_struct *rtlock_task; +}; + +#define DEFINE_RT_WAKE_Q(name) \ + struct rt_wake_q_head name = { \ + .head = WAKE_Q_HEAD_INITIALIZER(name.head), \ + .rtlock_task = NULL, \ + } + +/* + * PI-futex support (proxy locking functions, etc.): + */ +extern void rt_mutex_init_proxy_locked(struct rt_mutex_base *lock, + struct task_struct *proxy_owner); +extern void rt_mutex_proxy_unlock(struct rt_mutex_base *lock); +extern int __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *task); +extern int rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter, + struct task_struct *task); +extern int rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock, + struct hrtimer_sleeper *to, + struct rt_mutex_waiter *waiter); +extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter); + +extern int rt_mutex_futex_trylock(struct rt_mutex_base *l); +extern int __rt_mutex_futex_trylock(struct rt_mutex_base *l); + +extern void rt_mutex_futex_unlock(struct rt_mutex_base *lock); +extern bool __rt_mutex_futex_unlock(struct rt_mutex_base *lock, + struct rt_wake_q_head *wqh); + +extern void rt_mutex_postunlock(struct rt_wake_q_head *wqh); + /* * Must be guarded because this header is included from rcu/tree_plugin.h * unconditionally. */ #ifdef CONFIG_RT_MUTEXES -static inline int rt_mutex_has_waiters(struct rt_mutex *lock) +static inline int rt_mutex_has_waiters(struct rt_mutex_base *lock) { return !RB_EMPTY_ROOT(&lock->waiters.rb_root); } -static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock) +/* + * Lockless speculative check whether @waiter is still the top waiter on + * @lock. This is solely comparing pointers and not derefencing the + * leftmost entry which might be about to vanish. + */ +static inline bool rt_mutex_waiter_is_top_waiter(struct rt_mutex_base *lock, + struct rt_mutex_waiter *waiter) +{ + struct rb_node *leftmost = rb_first_cached(&lock->waiters); + + return rb_entry(leftmost, struct rt_mutex_waiter, tree_entry) == waiter; +} + +static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex_base *lock) { struct rb_node *leftmost = rb_first_cached(&lock->waiters); struct rt_mutex_waiter *w = NULL; @@ -72,19 +133,12 @@ static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p) #define RT_MUTEX_HAS_WAITERS 1UL -static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock) +static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock) { unsigned long owner = (unsigned long) READ_ONCE(lock->owner); return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS); } -#else /* CONFIG_RT_MUTEXES */ -/* Used in rcu/tree_plugin.h */ -static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock) -{ - return NULL; -} -#endif /* !CONFIG_RT_MUTEXES */ /* * Constants for rt mutex functions which have a selectable deadlock @@ -101,49 +155,21 @@ enum rtmutex_chainwalk { RT_MUTEX_FULL_CHAINWALK, }; -static inline void __rt_mutex_basic_init(struct rt_mutex *lock) +static inline void __rt_mutex_base_init(struct rt_mutex_base *lock) { - lock->owner = NULL; raw_spin_lock_init(&lock->wait_lock); lock->waiters = RB_ROOT_CACHED; + lock->owner = NULL; } -/* - * PI-futex support (proxy locking functions, etc.): - */ -extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock, - struct task_struct *proxy_owner); -extern void rt_mutex_proxy_unlock(struct rt_mutex *lock); -extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter); -extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter, - struct task_struct *task); -extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter, - struct task_struct *task); -extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock, - struct hrtimer_sleeper *to, - struct rt_mutex_waiter *waiter); -extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock, - struct rt_mutex_waiter *waiter); - -extern int rt_mutex_futex_trylock(struct rt_mutex *l); -extern int __rt_mutex_futex_trylock(struct rt_mutex *l); - -extern void rt_mutex_futex_unlock(struct rt_mutex *lock); -extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock, - struct wake_q_head *wqh); - -extern void rt_mutex_postunlock(struct wake_q_head *wake_q); - /* Debug functions */ -static inline void debug_rt_mutex_unlock(struct rt_mutex *lock) +static inline void debug_rt_mutex_unlock(struct rt_mutex_base *lock) { if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES)) DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current); } -static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock) +static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex_base *lock) { if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES)) DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock)); @@ -161,4 +187,27 @@ static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) memset(waiter, 0x22, sizeof(*waiter)); } +static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) +{ + debug_rt_mutex_init_waiter(waiter); + RB_CLEAR_NODE(&waiter->pi_tree_entry); + RB_CLEAR_NODE(&waiter->tree_entry); + waiter->wake_state = TASK_NORMAL; + waiter->task = NULL; +} + +static inline void rt_mutex_init_rtlock_waiter(struct rt_mutex_waiter *waiter) +{ + rt_mutex_init_waiter(waiter); + waiter->wake_state = TASK_RTLOCK_WAIT; +} + +#else /* CONFIG_RT_MUTEXES */ +/* Used in rcu/tree_plugin.h */ +static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock) +{ + return NULL; +} +#endif /* !CONFIG_RT_MUTEXES */ + #endif diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c new file mode 100644 index 000000000000..4ba15088e640 --- /dev/null +++ b/kernel/locking/rwbase_rt.c @@ -0,0 +1,263 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * RT-specific reader/writer semaphores and reader/writer locks + * + * down_write/write_lock() + * 1) Lock rtmutex + * 2) Remove the reader BIAS to force readers into the slow path + * 3) Wait until all readers have left the critical section + * 4) Mark it write locked + * + * up_write/write_unlock() + * 1) Remove the write locked marker + * 2) Set the reader BIAS, so readers can use the fast path again + * 3) Unlock rtmutex, to release blocked readers + * + * down_read/read_lock() + * 1) Try fast path acquisition (reader BIAS is set) + * 2) Take tmutex::wait_lock, which protects the writelocked flag + * 3) If !writelocked, acquire it for read + * 4) If writelocked, block on tmutex + * 5) unlock rtmutex, goto 1) + * + * up_read/read_unlock() + * 1) Try fast path release (reader count != 1) + * 2) Wake the writer waiting in down_write()/write_lock() #3 + * + * down_read/read_lock()#3 has the consequence, that rw semaphores and rw + * locks on RT are not writer fair, but writers, which should be avoided in + * RT tasks (think mmap_sem), are subject to the rtmutex priority/DL + * inheritance mechanism. + * + * It's possible to make the rw primitives writer fair by keeping a list of + * active readers. A blocked writer would force all newly incoming readers + * to block on the rtmutex, but the rtmutex would have to be proxy locked + * for one reader after the other. We can't use multi-reader inheritance + * because there is no way to support that with SCHED_DEADLINE. + * Implementing the one by one reader boosting/handover mechanism is a + * major surgery for a very dubious value. + * + * The risk of writer starvation is there, but the pathological use cases + * which trigger it are not necessarily the typical RT workloads. + * + * Common code shared between RT rw_semaphore and rwlock + */ + +static __always_inline int rwbase_read_trylock(struct rwbase_rt *rwb) +{ + int r; + + /* + * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is + * set. + */ + for (r = atomic_read(&rwb->readers); r < 0;) { + if (likely(atomic_try_cmpxchg(&rwb->readers, &r, r + 1))) + return 1; + } + return 0; +} + +static int __sched __rwbase_read_lock(struct rwbase_rt *rwb, + unsigned int state) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + int ret; + + raw_spin_lock_irq(&rtm->wait_lock); + /* + * Allow readers, as long as the writer has not completely + * acquired the semaphore for write. + */ + if (atomic_read(&rwb->readers) != WRITER_BIAS) { + atomic_inc(&rwb->readers); + raw_spin_unlock_irq(&rtm->wait_lock); + return 0; + } + + /* + * Call into the slow lock path with the rtmutex->wait_lock + * held, so this can't result in the following race: + * + * Reader1 Reader2 Writer + * down_read() + * down_write() + * rtmutex_lock(m) + * wait() + * down_read() + * unlock(m->wait_lock) + * up_read() + * wake(Writer) + * lock(m->wait_lock) + * sem->writelocked=true + * unlock(m->wait_lock) + * + * up_write() + * sem->writelocked=false + * rtmutex_unlock(m) + * down_read() + * down_write() + * rtmutex_lock(m) + * wait() + * rtmutex_lock(m) + * + * That would put Reader1 behind the writer waiting on + * Reader2 to call up_read(), which might be unbound. + */ + + /* + * For rwlocks this returns 0 unconditionally, so the below + * !ret conditionals are optimized out. + */ + ret = rwbase_rtmutex_slowlock_locked(rtm, state); + + /* + * On success the rtmutex is held, so there can't be a writer + * active. Increment the reader count and immediately drop the + * rtmutex again. + * + * rtmutex->wait_lock has to be unlocked in any case of course. + */ + if (!ret) + atomic_inc(&rwb->readers); + raw_spin_unlock_irq(&rtm->wait_lock); + if (!ret) + rwbase_rtmutex_unlock(rtm); + return ret; +} + +static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb, + unsigned int state) +{ + if (rwbase_read_trylock(rwb)) + return 0; + + return __rwbase_read_lock(rwb, state); +} + +static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb, + unsigned int state) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + struct task_struct *owner; + + raw_spin_lock_irq(&rtm->wait_lock); + /* + * Wake the writer, i.e. the rtmutex owner. It might release the + * rtmutex concurrently in the fast path (due to a signal), but to + * clean up rwb->readers it needs to acquire rtm->wait_lock. The + * worst case which can happen is a spurious wakeup. + */ + owner = rt_mutex_owner(rtm); + if (owner) + wake_up_state(owner, state); + + raw_spin_unlock_irq(&rtm->wait_lock); +} + +static __always_inline void rwbase_read_unlock(struct rwbase_rt *rwb, + unsigned int state) +{ + /* + * rwb->readers can only hit 0 when a writer is waiting for the + * active readers to leave the critical section. + */ + if (unlikely(atomic_dec_and_test(&rwb->readers))) + __rwbase_read_unlock(rwb, state); +} + +static inline void __rwbase_write_unlock(struct rwbase_rt *rwb, int bias, + unsigned long flags) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + + atomic_add(READER_BIAS - bias, &rwb->readers); + raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); + rwbase_rtmutex_unlock(rtm); +} + +static inline void rwbase_write_unlock(struct rwbase_rt *rwb) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + unsigned long flags; + + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + __rwbase_write_unlock(rwb, WRITER_BIAS, flags); +} + +static inline void rwbase_write_downgrade(struct rwbase_rt *rwb) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + unsigned long flags; + + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + /* Release it and account current as reader */ + __rwbase_write_unlock(rwb, WRITER_BIAS - 1, flags); +} + +static int __sched rwbase_write_lock(struct rwbase_rt *rwb, + unsigned int state) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + unsigned long flags; + + /* Take the rtmutex as a first step */ + if (rwbase_rtmutex_lock_state(rtm, state)) + return -EINTR; + + /* Force readers into slow path */ + atomic_sub(READER_BIAS, &rwb->readers); + + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + /* + * set_current_state() for rw_semaphore + * current_save_and_set_rtlock_wait_state() for rwlock + */ + rwbase_set_and_save_current_state(state); + + /* Block until all readers have left the critical section. */ + for (; atomic_read(&rwb->readers);) { + /* Optimized out for rwlocks */ + if (rwbase_signal_pending_state(state, current)) { + __set_current_state(TASK_RUNNING); + __rwbase_write_unlock(rwb, 0, flags); + return -EINTR; + } + raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); + + /* + * Schedule and wait for the readers to leave the critical + * section. The last reader leaving it wakes the waiter. + */ + if (atomic_read(&rwb->readers) != 0) + rwbase_schedule(); + set_current_state(state); + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + } + + atomic_set(&rwb->readers, WRITER_BIAS); + rwbase_restore_current_state(); + raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); + return 0; +} + +static inline int rwbase_write_trylock(struct rwbase_rt *rwb) +{ + struct rt_mutex_base *rtm = &rwb->rtmutex; + unsigned long flags; + + if (!rwbase_rtmutex_trylock(rtm)) + return 0; + + atomic_sub(READER_BIAS, &rwb->readers); + + raw_spin_lock_irqsave(&rtm->wait_lock, flags); + if (!atomic_read(&rwb->readers)) { + atomic_set(&rwb->readers, WRITER_BIAS); + raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); + return 1; + } + __rwbase_write_unlock(rwb, 0, flags); + return 0; +} diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 1d42c1873638..8e6c48c4eb49 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -28,6 +28,7 @@ #include <linux/rwsem.h> #include <linux/atomic.h> +#ifndef CONFIG_PREEMPT_RT #include "lock_events.h" /* @@ -1351,6 +1352,114 @@ static inline void __downgrade_write(struct rw_semaphore *sem) rwsem_downgrade_wake(sem); } +#else /* !CONFIG_PREEMPT_RT */ + +#define RT_MUTEX_BUILD_MUTEX +#include "rtmutex.c" + +#define rwbase_set_and_save_current_state(state) \ + set_current_state(state) + +#define rwbase_restore_current_state() \ + __set_current_state(TASK_RUNNING) + +#define rwbase_rtmutex_lock_state(rtm, state) \ + __rt_mutex_lock(rtm, state) + +#define rwbase_rtmutex_slowlock_locked(rtm, state) \ + __rt_mutex_slowlock_locked(rtm, NULL, state) + +#define rwbase_rtmutex_unlock(rtm) \ + __rt_mutex_unlock(rtm) + +#define rwbase_rtmutex_trylock(rtm) \ + __rt_mutex_trylock(rtm) + +#define rwbase_signal_pending_state(state, current) \ + signal_pending_state(state, current) + +#define rwbase_schedule() \ + schedule() + +#include "rwbase_rt.c" + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void __rwsem_init(struct rw_semaphore *sem, const char *name, + struct lock_class_key *key) +{ + debug_check_no_locks_freed((void *)sem, sizeof(*sem)); + lockdep_init_map_wait(&sem->dep_map, name, key, 0, LD_WAIT_SLEEP); +} +EXPORT_SYMBOL(__rwsem_init); +#endif + +static inline void __down_read(struct rw_semaphore *sem) +{ + rwbase_read_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE); +} + +static inline int __down_read_interruptible(struct rw_semaphore *sem) +{ + return rwbase_read_lock(&sem->rwbase, TASK_INTERRUPTIBLE); +} + +static inline int __down_read_killable(struct rw_semaphore *sem) +{ + return rwbase_read_lock(&sem->rwbase, TASK_KILLABLE); +} + +static inline int __down_read_trylock(struct rw_semaphore *sem) +{ + return rwbase_read_trylock(&sem->rwbase); +} + +static inline void __up_read(struct rw_semaphore *sem) +{ + rwbase_read_unlock(&sem->rwbase, TASK_NORMAL); +} + +static inline void __sched __down_write(struct rw_semaphore *sem) +{ + rwbase_write_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE); +} + +static inline int __sched __down_write_killable(struct rw_semaphore *sem) +{ + return rwbase_write_lock(&sem->rwbase, TASK_KILLABLE); +} + +static inline int __down_write_trylock(struct rw_semaphore *sem) +{ + return rwbase_write_trylock(&sem->rwbase); +} + +static inline void __up_write(struct rw_semaphore *sem) +{ + rwbase_write_unlock(&sem->rwbase); +} + +static inline void __downgrade_write(struct rw_semaphore *sem) +{ + rwbase_write_downgrade(&sem->rwbase); +} + +/* Debug stubs for the common API */ +#define DEBUG_RWSEMS_WARN_ON(c, sem) + +static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem, + struct task_struct *owner) +{ +} + +static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem) +{ + int count = atomic_read(&sem->rwbase.readers); + + return count < 0 && count != READER_BIAS; +} + +#endif /* CONFIG_PREEMPT_RT */ + /* * lock for reading */ diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c index c8d7ad9fb9b2..c5830cfa379a 100644 --- a/kernel/locking/spinlock.c +++ b/kernel/locking/spinlock.c @@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \ * __[spin|read|write]_lock_bh() */ BUILD_LOCK_OPS(spin, raw_spinlock); + +#ifndef CONFIG_PREEMPT_RT BUILD_LOCK_OPS(read, rwlock); BUILD_LOCK_OPS(write, rwlock); +#endif #endif @@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock) EXPORT_SYMBOL(_raw_spin_unlock_bh); #endif +#ifndef CONFIG_PREEMPT_RT + #ifndef CONFIG_INLINE_READ_TRYLOCK int __lockfunc _raw_read_trylock(rwlock_t *lock) { @@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwlock_t *lock) EXPORT_SYMBOL(_raw_write_unlock_bh); #endif +#endif /* !CONFIG_PREEMPT_RT */ + #ifdef CONFIG_DEBUG_LOCK_ALLOC void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass) diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c index b9d93087ee66..14235671a1a7 100644 --- a/kernel/locking/spinlock_debug.c +++ b/kernel/locking/spinlock_debug.c @@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, EXPORT_SYMBOL(__raw_spin_lock_init); +#ifndef CONFIG_PREEMPT_RT void __rwlock_init(rwlock_t *lock, const char *name, struct lock_class_key *key) { @@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const char *name, } EXPORT_SYMBOL(__rwlock_init); +#endif static void spin_dump(raw_spinlock_t *lock, const char *msg) { @@ -139,6 +141,7 @@ void do_raw_spin_unlock(raw_spinlock_t *lock) arch_spin_unlock(&lock->raw_lock); } +#ifndef CONFIG_PREEMPT_RT static void rwlock_bug(rwlock_t *lock, const char *msg) { if (!debug_locks_off()) @@ -228,3 +231,5 @@ void do_raw_write_unlock(rwlock_t *lock) debug_write_unlock(lock); arch_write_unlock(&lock->raw_lock); } + +#endif /* !CONFIG_PREEMPT_RT */ diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c new file mode 100644 index 000000000000..839041f8460f --- /dev/null +++ b/kernel/locking/spinlock_rt.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PREEMPT_RT substitution for spin/rw_locks + * + * spinlocks and rwlocks on RT are based on rtmutexes, with a few twists to + * resemble the non RT semantics: + * + * - Contrary to plain rtmutexes, spinlocks and rwlocks are state + * preserving. The task state is saved before blocking on the underlying + * rtmutex, and restored when the lock has been acquired. Regular wakeups + * during that time are redirected to the saved state so no wake up is + * missed. + * + * - Non RT spin/rwlocks disable preemption and eventually interrupts. + * Disabling preemption has the side effect of disabling migration and + * preventing RCU grace periods. + * + * The RT substitutions explicitly disable migration and take + * rcu_read_lock() across the lock held section. + */ +#include <linux/spinlock.h> +#include <linux/export.h> + +#define RT_MUTEX_BUILD_SPINLOCKS +#include "rtmutex.c" + +static __always_inline void rtlock_lock(struct rt_mutex_base *rtm) +{ + if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current))) + rtlock_slowlock(rtm); +} + +static __always_inline void __rt_spin_lock(spinlock_t *lock) +{ + ___might_sleep(__FILE__, __LINE__, 0); + rtlock_lock(&lock->lock); + rcu_read_lock(); + migrate_disable(); +} + +void __sched rt_spin_lock(spinlock_t *lock) +{ + spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); + __rt_spin_lock(lock); +} +EXPORT_SYMBOL(rt_spin_lock); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void __sched rt_spin_lock_nested(spinlock_t *lock, int subclass) +{ + spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + __rt_spin_lock(lock); +} +EXPORT_SYMBOL(rt_spin_lock_nested); + +void __sched rt_spin_lock_nest_lock(spinlock_t *lock, + struct lockdep_map *nest_lock) +{ + spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); + __rt_spin_lock(lock); +} +EXPORT_SYMBOL(rt_spin_lock_nest_lock); +#endif + +void __sched rt_spin_unlock(spinlock_t *lock) +{ + spin_release(&lock->dep_map, _RET_IP_); + migrate_enable(); + rcu_read_unlock(); + + if (unlikely(!rt_mutex_cmpxchg_release(&lock->lock, current, NULL))) + rt_mutex_slowunlock(&lock->lock); +} +EXPORT_SYMBOL(rt_spin_unlock); + +/* + * Wait for the lock to get unlocked: instead of polling for an unlock + * (like raw spinlocks do), lock and unlock, to force the kernel to + * schedule if there's contention: + */ +void __sched rt_spin_lock_unlock(spinlock_t *lock) +{ + spin_lock(lock); + spin_unlock(lock); +} +EXPORT_SYMBOL(rt_spin_lock_unlock); + +static __always_inline int __rt_spin_trylock(spinlock_t *lock) +{ + int ret = 1; + + if (unlikely(!rt_mutex_cmpxchg_acquire(&lock->lock, NULL, current))) + ret = rt_mutex_slowtrylock(&lock->lock); + + if (ret) { + spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); + migrate_disable(); + } + return ret; +} + +int __sched rt_spin_trylock(spinlock_t *lock) +{ + return __rt_spin_trylock(lock); +} +EXPORT_SYMBOL(rt_spin_trylock); + +int __sched rt_spin_trylock_bh(spinlock_t *lock) +{ + int ret; + + local_bh_disable(); + ret = __rt_spin_trylock(lock); + if (!ret) + local_bh_enable(); + return ret; +} +EXPORT_SYMBOL(rt_spin_trylock_bh); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void __rt_spin_lock_init(spinlock_t *lock, const char *name, + struct lock_class_key *key, bool percpu) +{ + u8 type = percpu ? LD_LOCK_PERCPU : LD_LOCK_NORMAL; + + debug_check_no_locks_freed((void *)lock, sizeof(*lock)); + lockdep_init_map_type(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG, + LD_WAIT_INV, type); +} +EXPORT_SYMBOL(__rt_spin_lock_init); +#endif + +/* + * RT-specific reader/writer locks + */ +#define rwbase_set_and_save_current_state(state) \ + current_save_and_set_rtlock_wait_state() + +#define rwbase_restore_current_state() \ + current_restore_rtlock_saved_state() + +static __always_inline int +rwbase_rtmutex_lock_state(struct rt_mutex_base *rtm, unsigned int state) +{ + if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current))) + rtlock_slowlock(rtm); + return 0; +} + +static __always_inline int +rwbase_rtmutex_slowlock_locked(struct rt_mutex_base *rtm, unsigned int state) +{ + rtlock_slowlock_locked(rtm); + return 0; +} + +static __always_inline void rwbase_rtmutex_unlock(struct rt_mutex_base *rtm) +{ + if (likely(rt_mutex_cmpxchg_acquire(rtm, current, NULL))) + return; + + rt_mutex_slowunlock(rtm); +} + +static __always_inline int rwbase_rtmutex_trylock(struct rt_mutex_base *rtm) +{ + if (likely(rt_mutex_cmpxchg_acquire(rtm, NULL, current))) + return 1; + + return rt_mutex_slowtrylock(rtm); +} + +#define rwbase_signal_pending_state(state, current) (0) + +#define rwbase_schedule() \ + schedule_rtlock() + +#include "rwbase_rt.c" +/* + * The common functions which get wrapped into the rwlock API. + */ +int __sched rt_read_trylock(rwlock_t *rwlock) +{ + int ret; + + ret = rwbase_read_trylock(&rwlock->rwbase); + if (ret) { + rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); + migrate_disable(); + } + return ret; +} +EXPORT_SYMBOL(rt_read_trylock); + +int __sched rt_write_trylock(rwlock_t *rwlock) +{ + int ret; + + ret = rwbase_write_trylock(&rwlock->rwbase); + if (ret) { + rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); + migrate_disable(); + } + return ret; +} +EXPORT_SYMBOL(rt_write_trylock); + +void __sched rt_read_lock(rwlock_t *rwlock) +{ + ___might_sleep(__FILE__, __LINE__, 0); + rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_); + rwbase_read_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT); + rcu_read_lock(); + migrate_disable(); +} +EXPORT_SYMBOL(rt_read_lock); + +void __sched rt_write_lock(rwlock_t *rwlock) +{ + ___might_sleep(__FILE__, __LINE__, 0); + rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); + rwbase_write_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT); + rcu_read_lock(); + migrate_disable(); +} +EXPORT_SYMBOL(rt_write_lock); + +void __sched rt_read_unlock(rwlock_t *rwlock) +{ + rwlock_release(&rwlock->dep_map, _RET_IP_); + migrate_enable(); + rcu_read_unlock(); + rwbase_read_unlock(&rwlock->rwbase, TASK_RTLOCK_WAIT); +} +EXPORT_SYMBOL(rt_read_unlock); + +void __sched rt_write_unlock(rwlock_t *rwlock) +{ + rwlock_release(&rwlock->dep_map, _RET_IP_); + rcu_read_unlock(); + migrate_enable(); + rwbase_write_unlock(&rwlock->rwbase); +} +EXPORT_SYMBOL(rt_write_unlock); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void __rt_rwlock_init(rwlock_t *rwlock, const char *name, + struct lock_class_key *key) +{ + debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock)); + lockdep_init_map_wait(&rwlock->dep_map, name, key, 0, LD_WAIT_CONFIG); +} +EXPORT_SYMBOL(__rt_rwlock_init); +#endif diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h new file mode 100644 index 000000000000..56f139201f24 --- /dev/null +++ b/kernel/locking/ww_mutex.h @@ -0,0 +1,569 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef WW_RT + +#define MUTEX mutex +#define MUTEX_WAITER mutex_waiter + +static inline struct mutex_waiter * +__ww_waiter_first(struct mutex *lock) +{ + struct mutex_waiter *w; + + w = list_first_entry(&lock->wait_list, struct mutex_waiter, list); + if (list_entry_is_head(w, &lock->wait_list, list)) + return NULL; + + return w; +} + +static inline struct mutex_waiter * +__ww_waiter_next(struct mutex *lock, struct mutex_waiter *w) +{ + w = list_next_entry(w, list); + if (list_entry_is_head(w, &lock->wait_list, list)) + return NULL; + + return w; +} + +static inline struct mutex_waiter * +__ww_waiter_prev(struct mutex *lock, struct mutex_waiter *w) +{ + w = list_prev_entry(w, list); + if (list_entry_is_head(w, &lock->wait_list, list)) + return NULL; + + return w; +} + +static inline struct mutex_waiter * +__ww_waiter_last(struct mutex *lock) +{ + struct mutex_waiter *w; + + w = list_last_entry(&lock->wait_list, struct mutex_waiter, list); + if (list_entry_is_head(w, &lock->wait_list, list)) + return NULL; + + return w; +} + +static inline void +__ww_waiter_add(struct mutex *lock, struct mutex_waiter *waiter, struct mutex_waiter *pos) +{ + struct list_head *p = &lock->wait_list; + if (pos) + p = &pos->list; + __mutex_add_waiter(lock, waiter, p); +} + +static inline struct task_struct * +__ww_mutex_owner(struct mutex *lock) +{ + return __mutex_owner(lock); +} + +static inline bool +__ww_mutex_has_waiters(struct mutex *lock) +{ + return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS; +} + +static inline void lock_wait_lock(struct mutex *lock) +{ + raw_spin_lock(&lock->wait_lock); +} + +static inline void unlock_wait_lock(struct mutex *lock) +{ + raw_spin_unlock(&lock->wait_lock); +} + +static inline void lockdep_assert_wait_lock_held(struct mutex *lock) +{ + lockdep_assert_held(&lock->wait_lock); +} + +#else /* WW_RT */ + +#define MUTEX rt_mutex +#define MUTEX_WAITER rt_mutex_waiter + +static inline struct rt_mutex_waiter * +__ww_waiter_first(struct rt_mutex *lock) +{ + struct rb_node *n = rb_first(&lock->rtmutex.waiters.rb_root); + if (!n) + return NULL; + return rb_entry(n, struct rt_mutex_waiter, tree_entry); +} + +static inline struct rt_mutex_waiter * +__ww_waiter_next(struct rt_mutex *lock, struct rt_mutex_waiter *w) +{ + struct rb_node *n = rb_next(&w->tree_entry); + if (!n) + return NULL; + return rb_entry(n, struct rt_mutex_waiter, tree_entry); +} + +static inline struct rt_mutex_waiter * +__ww_waiter_prev(struct rt_mutex *lock, struct rt_mutex_waiter *w) +{ + struct rb_node *n = rb_prev(&w->tree_entry); + if (!n) + return NULL; + return rb_entry(n, struct rt_mutex_waiter, tree_entry); +} + +static inline struct rt_mutex_waiter * +__ww_waiter_last(struct rt_mutex *lock) +{ + struct rb_node *n = rb_last(&lock->rtmutex.waiters.rb_root); + if (!n) + return NULL; + return rb_entry(n, struct rt_mutex_waiter, tree_entry); +} + +static inline void +__ww_waiter_add(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, struct rt_mutex_waiter *pos) +{ + /* RT unconditionally adds the waiter first and then removes it on error */ +} + +static inline struct task_struct * +__ww_mutex_owner(struct rt_mutex *lock) +{ + return rt_mutex_owner(&lock->rtmutex); +} + +static inline bool +__ww_mutex_has_waiters(struct rt_mutex *lock) +{ + return rt_mutex_has_waiters(&lock->rtmutex); +} + +static inline void lock_wait_lock(struct rt_mutex *lock) +{ + raw_spin_lock(&lock->rtmutex.wait_lock); +} + +static inline void unlock_wait_lock(struct rt_mutex *lock) +{ + raw_spin_unlock(&lock->rtmutex.wait_lock); +} + +static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock) +{ + lockdep_assert_held(&lock->rtmutex.wait_lock); +} + +#endif /* WW_RT */ + +/* + * Wait-Die: + * The newer transactions are killed when: + * It (the new transaction) makes a request for a lock being held + * by an older transaction. + * + * Wound-Wait: + * The newer transactions are wounded when: + * An older transaction makes a request for a lock being held by + * the newer transaction. + */ + +/* + * Associate the ww_mutex @ww with the context @ww_ctx under which we acquired + * it. + */ +static __always_inline void +ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx) +{ +#ifdef DEBUG_WW_MUTEXES + /* + * If this WARN_ON triggers, you used ww_mutex_lock to acquire, + * but released with a normal mutex_unlock in this call. + * + * This should never happen, always use ww_mutex_unlock. + */ + DEBUG_LOCKS_WARN_ON(ww->ctx); + + /* + * Not quite done after calling ww_acquire_done() ? + */ + DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire); + + if (ww_ctx->contending_lock) { + /* + * After -EDEADLK you tried to + * acquire a different ww_mutex? Bad! + */ + DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww); + + /* + * You called ww_mutex_lock after receiving -EDEADLK, + * but 'forgot' to unlock everything else first? + */ + DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0); + ww_ctx->contending_lock = NULL; + } + + /* + * Naughty, using a different class will lead to undefined behavior! + */ + DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class); +#endif + ww_ctx->acquired++; + ww->ctx = ww_ctx; +} + +/* + * Determine if @a is 'less' than @b. IOW, either @a is a lower priority task + * or, when of equal priority, a younger transaction than @b. + * + * Depending on the algorithm, @a will either need to wait for @b, or die. + */ +static inline bool +__ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b) +{ +/* + * Can only do the RT prio for WW_RT, because task->prio isn't stable due to PI, + * so the wait_list ordering will go wobbly. rt_mutex re-queues the waiter and + * isn't affected by this. + */ +#ifdef WW_RT + /* kernel prio; less is more */ + int a_prio = a->task->prio; + int b_prio = b->task->prio; + + if (rt_prio(a_prio) || rt_prio(b_prio)) { + + if (a_prio > b_prio) + return true; + + if (a_prio < b_prio) + return false; + + /* equal static prio */ + + if (dl_prio(a_prio)) { + if (dl_time_before(b->task->dl.deadline, + a->task->dl.deadline)) + return true; + + if (dl_time_before(a->task->dl.deadline, + b->task->dl.deadline)) + return false; + } + + /* equal prio */ + } +#endif + + /* FIFO order tie break -- bigger is younger */ + return (signed long)(a->stamp - b->stamp) > 0; +} + +/* + * Wait-Die; wake a lesser waiter context (when locks held) such that it can + * die. + * + * Among waiters with context, only the first one can have other locks acquired + * already (ctx->acquired > 0), because __ww_mutex_add_waiter() and + * __ww_mutex_check_kill() wake any but the earliest context. + */ +static bool +__ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter, + struct ww_acquire_ctx *ww_ctx) +{ + if (!ww_ctx->is_wait_die) + return false; + + if (waiter->ww_ctx->acquired > 0 && __ww_ctx_less(waiter->ww_ctx, ww_ctx)) { +#ifndef WW_RT + debug_mutex_wake_waiter(lock, waiter); +#endif + wake_up_process(waiter->task); + } + + return true; +} + +/* + * Wound-Wait; wound a lesser @hold_ctx if it holds the lock. + * + * Wound the lock holder if there are waiters with more important transactions + * than the lock holders. Even if multiple waiters may wound the lock holder, + * it's sufficient that only one does. + */ +static bool __ww_mutex_wound(struct MUTEX *lock, + struct ww_acquire_ctx *ww_ctx, + struct ww_acquire_ctx *hold_ctx) +{ + struct task_struct *owner = __ww_mutex_owner(lock); + + lockdep_assert_wait_lock_held(lock); + + /* + * Possible through __ww_mutex_add_waiter() when we race with + * ww_mutex_set_context_fastpath(). In that case we'll get here again + * through __ww_mutex_check_waiters(). + */ + if (!hold_ctx) + return false; + + /* + * Can have !owner because of __mutex_unlock_slowpath(), but if owner, + * it cannot go away because we'll have FLAG_WAITERS set and hold + * wait_lock. + */ + if (!owner) + return false; + + if (ww_ctx->acquired > 0 && __ww_ctx_less(hold_ctx, ww_ctx)) { + hold_ctx->wounded = 1; + + /* + * wake_up_process() paired with set_current_state() + * inserts sufficient barriers to make sure @owner either sees + * it's wounded in __ww_mutex_check_kill() or has a + * wakeup pending to re-read the wounded state. + */ + if (owner != current) + wake_up_process(owner); + + return true; + } + + return false; +} + +/* + * We just acquired @lock under @ww_ctx, if there are more important contexts + * waiting behind us on the wait-list, check if they need to die, or wound us. + * + * See __ww_mutex_add_waiter() for the list-order construction; basically the + * list is ordered by stamp, smallest (oldest) first. + * + * This relies on never mixing wait-die/wound-wait on the same wait-list; + * which is currently ensured by that being a ww_class property. + * + * The current task must not be on the wait list. + */ +static void +__ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) +{ + struct MUTEX_WAITER *cur; + + lockdep_assert_wait_lock_held(lock); + + for (cur = __ww_waiter_first(lock); cur; + cur = __ww_waiter_next(lock, cur)) { + + if (!cur->ww_ctx) + continue; + + if (__ww_mutex_die(lock, cur, ww_ctx) || + __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx)) + break; + } +} + +/* + * After acquiring lock with fastpath, where we do not hold wait_lock, set ctx + * and wake up any waiters so they can recheck. + */ +static __always_inline void +ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) +{ + ww_mutex_lock_acquired(lock, ctx); + + /* + * The lock->ctx update should be visible on all cores before + * the WAITERS check is done, otherwise contended waiters might be + * missed. The contended waiters will either see ww_ctx == NULL + * and keep spinning, or it will acquire wait_lock, add itself + * to waiter list and sleep. + */ + smp_mb(); /* See comments above and below. */ + + /* + * [W] ww->ctx = ctx [W] MUTEX_FLAG_WAITERS + * MB MB + * [R] MUTEX_FLAG_WAITERS [R] ww->ctx + * + * The memory barrier above pairs with the memory barrier in + * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx + * and/or !empty list. + */ + if (likely(!__ww_mutex_has_waiters(&lock->base))) + return; + + /* + * Uh oh, we raced in fastpath, check if any of the waiters need to + * die or wound us. + */ + lock_wait_lock(&lock->base); + __ww_mutex_check_waiters(&lock->base, ctx); + unlock_wait_lock(&lock->base); +} + +static __always_inline int +__ww_mutex_kill(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx) +{ + if (ww_ctx->acquired > 0) { +#ifdef DEBUG_WW_MUTEXES + struct ww_mutex *ww; + + ww = container_of(lock, struct ww_mutex, base); + DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock); + ww_ctx->contending_lock = ww; +#endif + return -EDEADLK; + } + + return 0; +} + +/* + * Check the wound condition for the current lock acquire. + * + * Wound-Wait: If we're wounded, kill ourself. + * + * Wait-Die: If we're trying to acquire a lock already held by an older + * context, kill ourselves. + * + * Since __ww_mutex_add_waiter() orders the wait-list on stamp, we only have to + * look at waiters before us in the wait-list. + */ +static inline int +__ww_mutex_check_kill(struct MUTEX *lock, struct MUTEX_WAITER *waiter, + struct ww_acquire_ctx *ctx) +{ + struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); + struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx); + struct MUTEX_WAITER *cur; + + if (ctx->acquired == 0) + return 0; + + if (!ctx->is_wait_die) { + if (ctx->wounded) + return __ww_mutex_kill(lock, ctx); + + return 0; + } + + if (hold_ctx && __ww_ctx_less(ctx, hold_ctx)) + return __ww_mutex_kill(lock, ctx); + + /* + * If there is a waiter in front of us that has a context, then its + * stamp is earlier than ours and we must kill ourself. + */ + for (cur = __ww_waiter_prev(lock, waiter); cur; + cur = __ww_waiter_prev(lock, cur)) { + + if (!cur->ww_ctx) + continue; + + return __ww_mutex_kill(lock, ctx); + } + + return 0; +} + +/* + * Add @waiter to the wait-list, keep the wait-list ordered by stamp, smallest + * first. Such that older contexts are preferred to acquire the lock over + * younger contexts. + * + * Waiters without context are interspersed in FIFO order. + * + * Furthermore, for Wait-Die kill ourself immediately when possible (there are + * older contexts already waiting) to avoid unnecessary waiting and for + * Wound-Wait ensure we wound the owning context when it is younger. + */ +static inline int +__ww_mutex_add_waiter(struct MUTEX_WAITER *waiter, + struct MUTEX *lock, + struct ww_acquire_ctx *ww_ctx) +{ + struct MUTEX_WAITER *cur, *pos = NULL; + bool is_wait_die; + + if (!ww_ctx) { + __ww_waiter_add(lock, waiter, NULL); + return 0; + } + + is_wait_die = ww_ctx->is_wait_die; + + /* + * Add the waiter before the first waiter with a higher stamp. + * Waiters without a context are skipped to avoid starving + * them. Wait-Die waiters may die here. Wound-Wait waiters + * never die here, but they are sorted in stamp order and + * may wound the lock holder. + */ + for (cur = __ww_waiter_last(lock); cur; + cur = __ww_waiter_prev(lock, cur)) { + + if (!cur->ww_ctx) + continue; + + if (__ww_ctx_less(ww_ctx, cur->ww_ctx)) { + /* + * Wait-Die: if we find an older context waiting, there + * is no point in queueing behind it, as we'd have to + * die the moment it would acquire the lock. + */ + if (is_wait_die) { + int ret = __ww_mutex_kill(lock, ww_ctx); + + if (ret) + return ret; + } + + break; + } + + pos = cur; + + /* Wait-Die: ensure younger waiters die. */ + __ww_mutex_die(lock, cur, ww_ctx); + } + + __ww_waiter_add(lock, waiter, pos); + + /* + * Wound-Wait: if we're blocking on a mutex owned by a younger context, + * wound that such that we might proceed. + */ + if (!is_wait_die) { + struct ww_mutex *ww = container_of(lock, struct ww_mutex, base); + + /* + * See ww_mutex_set_context_fastpath(). Orders setting + * MUTEX_FLAG_WAITERS vs the ww->ctx load, + * such that either we or the fastpath will wound @ww->ctx. + */ + smp_mb(); + __ww_mutex_wound(lock, ww_ctx, ww->ctx); + } + + return 0; +} + +static inline void __ww_mutex_unlock(struct ww_mutex *lock) +{ + if (lock->ctx) { +#ifdef DEBUG_WW_MUTEXES + DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired); +#endif + if (lock->ctx->acquired > 0) + lock->ctx->acquired--; + lock->ctx = NULL; + } +} diff --git a/kernel/locking/ww_rt_mutex.c b/kernel/locking/ww_rt_mutex.c new file mode 100644 index 000000000000..3f1fff7d2780 --- /dev/null +++ b/kernel/locking/ww_rt_mutex.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * rtmutex API + */ +#include <linux/spinlock.h> +#include <linux/export.h> + +#define RT_MUTEX_BUILD_MUTEX +#define WW_RT +#include "rtmutex.c" + +static int __sched +__ww_rt_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx, + unsigned int state, unsigned long ip) +{ + struct lockdep_map __maybe_unused *nest_lock = NULL; + struct rt_mutex *rtm = &lock->base; + int ret; + + might_sleep(); + + if (ww_ctx) { + if (unlikely(ww_ctx == READ_ONCE(lock->ctx))) + return -EALREADY; + + /* + * Reset the wounded flag after a kill. No other process can + * race and wound us here, since they can't have a valid owner + * pointer if we don't have any locks held. + */ + if (ww_ctx->acquired == 0) + ww_ctx->wounded = 0; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + nest_lock = &ww_ctx->dep_map; +#endif + } + mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip); + + if (likely(rt_mutex_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) { + if (ww_ctx) + ww_mutex_set_context_fastpath(lock, ww_ctx); + return 0; + } + + ret = rt_mutex_slowlock(&rtm->rtmutex, ww_ctx, state); + + if (ret) + mutex_release(&rtm->dep_map, ip); + return ret; +} + +int __sched +ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) +{ + return __ww_rt_mutex_lock(lock, ctx, TASK_UNINTERRUPTIBLE, _RET_IP_); +} +EXPORT_SYMBOL(ww_mutex_lock); + +int __sched +ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) +{ + return __ww_rt_mutex_lock(lock, ctx, TASK_INTERRUPTIBLE, _RET_IP_); +} +EXPORT_SYMBOL(ww_mutex_lock_interruptible); + +void __sched ww_mutex_unlock(struct ww_mutex *lock) +{ + struct rt_mutex *rtm = &lock->base; + + __ww_mutex_unlock(lock); + + mutex_release(&rtm->dep_map, _RET_IP_); + __rt_mutex_unlock(&rtm->rtmutex); +} +EXPORT_SYMBOL(ww_mutex_unlock); diff --git a/kernel/notifier.c b/kernel/notifier.c index 1b019cbca594..b8251dc0bc0f 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -172,25 +172,6 @@ int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, } EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister); -int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh, - unsigned long val_up, unsigned long val_down, void *v) -{ - unsigned long flags; - int ret; - - /* - * Musn't use RCU; because then the notifier list can - * change between the up and down traversal. - */ - spin_lock_irqsave(&nh->lock, flags); - ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v); - spin_unlock_irqrestore(&nh->lock, flags); - - return ret; -} -EXPORT_SYMBOL_GPL(atomic_notifier_call_chain_robust); -NOKPROBE_SYMBOL(atomic_notifier_call_chain_robust); - /** * atomic_notifier_call_chain - Call functions in an atomic notifier chain * @nh: Pointer to head of the atomic notifier chain diff --git a/kernel/panic.c b/kernel/panic.c index ea9ceb608735..73c794d8d204 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -178,12 +178,28 @@ static void panic_print_sys_info(void) void panic(const char *fmt, ...) { static char buf[1024]; + va_list args2; va_list args; long i, i_next = 0, len; int state = 0; int old_cpu, this_cpu; bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; + console_verbose(); + pr_emerg("Kernel panic - not syncing:\n"); + va_start(args2, fmt); + va_copy(args, args2); + vprintk(fmt, args2); + va_end(args2); +#ifdef CONFIG_DEBUG_BUGVERBOSE + /* + * Avoid nested stack-dumping if a panic occurs during oops processing + */ + if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) + dump_stack(); +#endif + pr_flush(1000, true); + /* * Disable local interrupts. This will prevent panic_smp_self_stop * from deadlocking the first cpu that invokes the panic, since @@ -214,24 +230,13 @@ void panic(const char *fmt, ...) if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) panic_smp_self_stop(); - console_verbose(); bust_spinlocks(1); - va_start(args, fmt); len = vscnprintf(buf, sizeof(buf), fmt, args); va_end(args); if (len && buf[len - 1] == '\n') buf[len - 1] = '\0'; - pr_emerg("Kernel panic - not syncing: %s\n", buf); -#ifdef CONFIG_DEBUG_BUGVERBOSE - /* - * Avoid nested stack-dumping if a panic occurs during oops processing - */ - if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) - dump_stack(); -#endif - /* * If kgdb is enabled, give it a chance to run before we stop all * the other CPUs or else we won't be able to debug processes left @@ -248,7 +253,6 @@ void panic(const char *fmt, ...) * Bypass the panic_cpu check and call __crash_kexec directly. */ if (!_crash_kexec_post_notifiers) { - printk_safe_flush_on_panic(); __crash_kexec(NULL); /* @@ -272,8 +276,6 @@ void panic(const char *fmt, ...) */ atomic_notifier_call_chain(&panic_notifier_list, 0, buf); - /* Call flush even twice. It tries harder with a single online CPU */ - printk_safe_flush_on_panic(); kmsg_dump(KMSG_DUMP_PANIC); /* @@ -543,9 +545,11 @@ static u64 oops_id; static int init_oops_id(void) { +#ifndef CONFIG_PREEMPT_RT if (!oops_id) get_random_bytes(&oops_id, sizeof(oops_id)); else +#endif oops_id++; return 0; @@ -556,6 +560,7 @@ static void print_oops_end_marker(void) { init_oops_id(); pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); + pr_flush(1000, true); } /* diff --git a/kernel/power/main.c b/kernel/power/main.c index 12c7e1bb442f..66158a5f9d6f 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -543,14 +543,13 @@ static int __init pm_debug_messages_setup(char *str) __setup("pm_debug_messages", pm_debug_messages_setup); /** - * __pm_pr_dbg - Print a suspend debug message to the kernel log. - * @defer: Whether or not to use printk_deferred() to print the message. + * pm_pr_dbg - Print a suspend debug message to the kernel log. * @fmt: Message format. * * The message will be emitted if enabled through the pm_debug_messages * sysfs attribute. */ -void __pm_pr_dbg(bool defer, const char *fmt, ...) +void pm_pr_dbg(const char *fmt, ...) { struct va_format vaf; va_list args; @@ -563,10 +562,7 @@ void __pm_pr_dbg(bool defer, const char *fmt, ...) vaf.fmt = fmt; vaf.va = &args; - if (defer) - printk_deferred(KERN_DEBUG "PM: %pV", &vaf); - else - printk(KERN_DEBUG "PM: %pV", &vaf); + printk(KERN_DEBUG "PM: %pV", &vaf); va_end(args); } diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index eee3dc9b60a9..59cb24e25f00 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,5 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y = printk.o -obj-$(CONFIG_PRINTK) += printk_safe.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o obj-$(CONFIG_PRINTK) += printk_ringbuffer.o diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h deleted file mode 100644 index 51615c909b2f..000000000000 --- a/kernel/printk/internal.h +++ /dev/null @@ -1,69 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* - * internal.h - printk internal definitions - */ -#include <linux/percpu.h> - -#ifdef CONFIG_PRINTK - -#define PRINTK_SAFE_CONTEXT_MASK 0x007ffffff -#define PRINTK_NMI_DIRECT_CONTEXT_MASK 0x008000000 -#define PRINTK_NMI_CONTEXT_MASK 0xff0000000 - -#define PRINTK_NMI_CONTEXT_OFFSET 0x010000000 - -__printf(4, 0) -int vprintk_store(int facility, int level, - const struct dev_printk_info *dev_info, - const char *fmt, va_list args); - -__printf(1, 0) int vprintk_default(const char *fmt, va_list args); -__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args); -void __printk_safe_enter(void); -void __printk_safe_exit(void); - -void printk_safe_init(void); -bool printk_percpu_data_ready(void); - -#define printk_safe_enter_irqsave(flags) \ - do { \ - local_irq_save(flags); \ - __printk_safe_enter(); \ - } while (0) - -#define printk_safe_exit_irqrestore(flags) \ - do { \ - __printk_safe_exit(); \ - local_irq_restore(flags); \ - } while (0) - -#define printk_safe_enter_irq() \ - do { \ - local_irq_disable(); \ - __printk_safe_enter(); \ - } while (0) - -#define printk_safe_exit_irq() \ - do { \ - __printk_safe_exit(); \ - local_irq_enable(); \ - } while (0) - -void defer_console_output(void); - -#else - -/* - * In !PRINTK builds we still export console_sem - * semaphore and some of console functions (console_unlock()/etc.), so - * printk-safe must preserve the existing local IRQ guarantees. - */ -#define printk_safe_enter_irqsave(flags) local_irq_save(flags) -#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) - -#define printk_safe_enter_irq() local_irq_disable() -#define printk_safe_exit_irq() local_irq_enable() - -static inline void printk_safe_init(void) { } -static inline bool printk_percpu_data_ready(void) { return false; } -#endif /* CONFIG_PRINTK */ diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 6dad7da8f383..500ae4b18864 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -44,6 +44,10 @@ #include <linux/irq_work.h> #include <linux/ctype.h> #include <linux/uio.h> +#include <linux/kdb.h> +#include <linux/kgdb.h> +#include <linux/kthread.h> +#include <linux/clocksource.h> #include <linux/sched/clock.h> #include <linux/sched/debug.h> #include <linux/sched/task_stack.h> @@ -58,7 +62,6 @@ #include "printk_ringbuffer.h" #include "console_cmdline.h" #include "braille.h" -#include "internal.h" int console_printk[4] = { CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ @@ -225,19 +228,7 @@ static int nr_ext_console_drivers; static int __down_trylock_console_sem(unsigned long ip) { - int lock_failed; - unsigned long flags; - - /* - * Here and in __up_console_sem() we need to be in safe mode, - * because spindump/WARN/etc from under console ->lock will - * deadlock in printk()->down_trylock_console_sem() otherwise. - */ - printk_safe_enter_irqsave(flags); - lock_failed = down_trylock(&console_sem); - printk_safe_exit_irqrestore(flags); - - if (lock_failed) + if (down_trylock(&console_sem)) return 1; mutex_acquire(&console_lock_dep_map, 0, 1, ip); return 0; @@ -246,13 +237,9 @@ static int __down_trylock_console_sem(unsigned long ip) static void __up_console_sem(unsigned long ip) { - unsigned long flags; - mutex_release(&console_lock_dep_map, ip); - printk_safe_enter_irqsave(flags); up(&console_sem); - printk_safe_exit_irqrestore(flags); } #define up_console_sem() __up_console_sem(_RET_IP_) @@ -267,11 +254,6 @@ static void __up_console_sem(unsigned long ip) static int console_locked, console_suspended; /* - * If exclusive_console is non-NULL then only this console is to be printed to. - */ -static struct console *exclusive_console; - -/* * Array of consoles built from command line options (console=) */ @@ -355,10 +337,13 @@ enum log_flags { LOG_CONT = 8, /* text is a fragment of a continuation line */ }; +#ifdef CONFIG_PRINTK /* syslog_lock protects syslog_* variables and write access to clear_seq. */ -static DEFINE_RAW_SPINLOCK(syslog_lock); +static DEFINE_MUTEX(syslog_lock); + +/* Set to enable sync mode. Once set, it is never cleared. */ +static bool sync_mode; -#ifdef CONFIG_PRINTK DECLARE_WAIT_QUEUE_HEAD(log_wait); /* All 3 protected by @syslog_lock. */ /* the next printk record to read by syslog(READ) or /proc/kmsg */ @@ -366,17 +351,6 @@ static u64 syslog_seq; static size_t syslog_partial; static bool syslog_time; -/* All 3 protected by @console_sem. */ -/* the next printk record to write to the console */ -static u64 console_seq; -static u64 exclusive_console_stop_seq; -static unsigned long console_dropped; - -struct latched_seq { - seqcount_latch_t latch; - u64 val[2]; -}; - /* * The next printk record to read after the last 'clear' command. There are * two copies (updated with seqcount_latch) so that reads can locklessly @@ -394,9 +368,6 @@ static struct latched_seq clear_seq = { #define PREFIX_MAX 32 #endif -/* the maximum size of a formatted record (i.e. with prefix added per line) */ -#define CONSOLE_LOG_MAX 1024 - /* the maximum size allowed to be reserved for a record */ #define LOG_LINE_MAX (CONSOLE_LOG_MAX - PREFIX_MAX) @@ -435,12 +406,12 @@ static struct printk_ringbuffer *prb = &printk_rb_static; */ static bool __printk_percpu_data_ready __read_mostly; -bool printk_percpu_data_ready(void) +static bool printk_percpu_data_ready(void) { return __printk_percpu_data_ready; } -/* Must be called under syslog_lock. */ +/* Must be called under associated write-protection lock. */ static void latched_seq_write(struct latched_seq *ls, u64 val) { raw_write_seqcount_latch(&ls->latch); @@ -732,27 +703,22 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, if (ret) return ret; - printk_safe_enter_irq(); if (!prb_read_valid(prb, atomic64_read(&user->seq), r)) { if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; - printk_safe_exit_irq(); goto out; } - printk_safe_exit_irq(); ret = wait_event_interruptible(log_wait, prb_read_valid(prb, atomic64_read(&user->seq), r)); if (ret) goto out; - printk_safe_enter_irq(); } if (r->info->seq != atomic64_read(&user->seq)) { /* our last seen message is gone, return error and reset */ atomic64_set(&user->seq, r->info->seq); ret = -EPIPE; - printk_safe_exit_irq(); goto out; } @@ -762,7 +728,6 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, &r->info->dev_info); atomic64_set(&user->seq, r->info->seq + 1); - printk_safe_exit_irq(); if (len > count) { ret = -EINVAL; @@ -797,7 +762,6 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) if (offset) return -ESPIPE; - printk_safe_enter_irq(); switch (whence) { case SEEK_SET: /* the first record */ @@ -818,7 +782,6 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) default: ret = -EINVAL; } - printk_safe_exit_irq(); return ret; } @@ -833,7 +796,6 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait) poll_wait(file, &log_wait, wait); - printk_safe_enter_irq(); if (prb_read_valid_info(prb, atomic64_read(&user->seq), &info, NULL)) { /* return error when data has vanished underneath us */ if (info.seq != atomic64_read(&user->seq)) @@ -841,7 +803,6 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait) else ret = EPOLLIN|EPOLLRDNORM; } - printk_safe_exit_irq(); return ret; } @@ -874,9 +835,7 @@ static int devkmsg_open(struct inode *inode, struct file *file) prb_rec_init_rd(&user->record, &user->info, &user->text_buf[0], sizeof(user->text_buf)); - printk_safe_enter_irq(); atomic64_set(&user->seq, prb_first_valid_seq(prb)); - printk_safe_exit_irq(); file->private_data = user; return 0; @@ -1042,9 +1001,6 @@ static inline void log_buf_add_cpu(void) {} static void __init set_percpu_data_ready(void) { - printk_safe_init(); - /* Make sure we set this flag only after printk_safe() init is done */ - barrier(); __printk_percpu_data_ready = true; } @@ -1082,6 +1038,7 @@ void __init setup_log_buf(int early) struct prb_desc *new_descs; struct printk_info info; struct printk_record r; + unsigned int text_size; size_t new_descs_size; size_t new_infos_size; unsigned long flags; @@ -1142,24 +1099,37 @@ void __init setup_log_buf(int early) new_descs, ilog2(new_descs_count), new_infos); - printk_safe_enter_irqsave(flags); + local_irq_save(flags); log_buf_len = new_log_buf_len; log_buf = new_log_buf; new_log_buf_len = 0; free = __LOG_BUF_LEN; - prb_for_each_record(0, &printk_rb_static, seq, &r) - free -= add_to_rb(&printk_rb_dynamic, &r); + prb_for_each_record(0, &printk_rb_static, seq, &r) { + text_size = add_to_rb(&printk_rb_dynamic, &r); + if (text_size > free) + free = 0; + else + free -= text_size; + } - /* - * This is early enough that everything is still running on the - * boot CPU and interrupts are disabled. So no new messages will - * appear during the transition to the dynamic buffer. - */ prb = &printk_rb_dynamic; - printk_safe_exit_irqrestore(flags); + local_irq_restore(flags); + + /* + * Copy any remaining messages that might have appeared from + * NMI context after copying but before switching to the + * dynamic buffer. + */ + prb_for_each_record(seq, &printk_rb_static, seq, &r) { + text_size = add_to_rb(&printk_rb_dynamic, &r); + if (text_size > free) + free = 0; + else + free -= text_size; + } if (seq != prb_next_seq(&printk_rb_static)) { pr_err("dropped %llu messages\n", @@ -1481,12 +1451,14 @@ static u64 find_first_fitting_seq(u64 start_seq, u64 max_seq, size_t size, return seq; } +/* The caller is responsible for making sure @size is greater than 0. */ static int syslog_print(char __user *buf, int size) { struct printk_info info; struct printk_record r; char *text; int len = 0; + u64 seq; text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL); if (!text) @@ -1494,17 +1466,35 @@ static int syslog_print(char __user *buf, int size) prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX); - while (size > 0) { + mutex_lock(&syslog_lock); + + /* + * Wait for the @syslog_seq record to be available. @syslog_seq may + * change while waiting. + */ + do { + seq = syslog_seq; + + mutex_unlock(&syslog_lock); + len = wait_event_interruptible(log_wait, prb_read_valid(prb, seq, NULL)); + mutex_lock(&syslog_lock); + + if (len) + goto out; + } while (syslog_seq != seq); + + /* + * Copy records that fit into the buffer. The above cycle makes sure + * that the first record is always available. + */ + do { size_t n; size_t skip; + int err; - printk_safe_enter_irq(); - raw_spin_lock(&syslog_lock); - if (!prb_read_valid(prb, syslog_seq, &r)) { - raw_spin_unlock(&syslog_lock); - printk_safe_exit_irq(); + if (!prb_read_valid(prb, syslog_seq, &r)) break; - } + if (r.info->seq != syslog_seq) { /* message is gone, move to next valid one */ syslog_seq = r.info->seq; @@ -1531,13 +1521,15 @@ static int syslog_print(char __user *buf, int size) syslog_partial += n; } else n = 0; - raw_spin_unlock(&syslog_lock); - printk_safe_exit_irq(); if (!n) break; - if (copy_to_user(buf, text + skip, n)) { + mutex_unlock(&syslog_lock); + err = copy_to_user(buf, text + skip, n); + mutex_lock(&syslog_lock); + + if (err) { if (!len) len = -EFAULT; break; @@ -1546,8 +1538,9 @@ static int syslog_print(char __user *buf, int size) len += n; size -= n; buf += n; - } - + } while (size); +out: + mutex_unlock(&syslog_lock); kfree(text); return len; } @@ -1566,7 +1559,6 @@ static int syslog_print_all(char __user *buf, int size, bool clear) return -ENOMEM; time = printk_time; - printk_safe_enter_irq(); /* * Find first record that fits, including all following records, * into the user-provided buffer for this dump. @@ -1587,23 +1579,20 @@ static int syslog_print_all(char __user *buf, int size, bool clear) break; } - printk_safe_exit_irq(); if (copy_to_user(buf + len, text, textlen)) len = -EFAULT; else len += textlen; - printk_safe_enter_irq(); if (len < 0) break; } if (clear) { - raw_spin_lock(&syslog_lock); + mutex_lock(&syslog_lock); latched_seq_write(&clear_seq, seq); - raw_spin_unlock(&syslog_lock); + mutex_unlock(&syslog_lock); } - printk_safe_exit_irq(); kfree(text); return len; @@ -1611,23 +1600,9 @@ static int syslog_print_all(char __user *buf, int size, bool clear) static void syslog_clear(void) { - printk_safe_enter_irq(); - raw_spin_lock(&syslog_lock); + mutex_lock(&syslog_lock); latched_seq_write(&clear_seq, prb_next_seq(prb)); - raw_spin_unlock(&syslog_lock); - printk_safe_exit_irq(); -} - -/* Return a consistent copy of @syslog_seq. */ -static u64 read_syslog_seq_irq(void) -{ - u64 seq; - - raw_spin_lock_irq(&syslog_lock); - seq = syslog_seq; - raw_spin_unlock_irq(&syslog_lock); - - return seq; + mutex_unlock(&syslog_lock); } int do_syslog(int type, char __user *buf, int len, int source) @@ -1653,11 +1628,6 @@ int do_syslog(int type, char __user *buf, int len, int source) return 0; if (!access_ok(buf, len)) return -EFAULT; - - error = wait_event_interruptible(log_wait, - prb_read_valid(prb, read_syslog_seq_irq(), NULL)); - if (error) - return error; error = syslog_print(buf, len); break; /* Read/clear last kernel messages */ @@ -1703,12 +1673,10 @@ int do_syslog(int type, char __user *buf, int len, int source) break; /* Number of chars in the log buffer */ case SYSLOG_ACTION_SIZE_UNREAD: - printk_safe_enter_irq(); - raw_spin_lock(&syslog_lock); + mutex_lock(&syslog_lock); if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) { /* No unread messages. */ - raw_spin_unlock(&syslog_lock); - printk_safe_exit_irq(); + mutex_unlock(&syslog_lock); return 0; } if (info.seq != syslog_seq) { @@ -1736,8 +1704,7 @@ int do_syslog(int type, char __user *buf, int len, int source) } error -= syslog_partial; } - raw_spin_unlock(&syslog_lock); - printk_safe_exit_irq(); + mutex_unlock(&syslog_lock); break; /* Size of the log buffer */ case SYSLOG_ACTION_SIZE_BUFFER: @@ -1756,204 +1723,224 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) return do_syslog(type, buf, len, SYSLOG_FROM_READER); } -/* - * Special console_lock variants that help to reduce the risk of soft-lockups. - * They allow to pass console_lock to another printk() call using a busy wait. - */ +int printk_delay_msec __read_mostly; -#ifdef CONFIG_LOCKDEP -static struct lockdep_map console_owner_dep_map = { - .name = "console_owner" -}; -#endif +static inline void printk_delay(int level) +{ + boot_delay_msec(level); -static DEFINE_RAW_SPINLOCK(console_owner_lock); -static struct task_struct *console_owner; -static bool console_waiter; + if (unlikely(printk_delay_msec)) { + int m = printk_delay_msec; -/** - * console_lock_spinning_enable - mark beginning of code where another - * thread might safely busy wait - * - * This basically converts console_lock into a spinlock. This marks - * the section where the console_lock owner can not sleep, because - * there may be a waiter spinning (like a spinlock). Also it must be - * ready to hand over the lock at the end of the section. - */ -static void console_lock_spinning_enable(void) + while (m--) { + mdelay(1); + touch_nmi_watchdog(); + } + } +} + +static bool kernel_sync_mode(void) { - raw_spin_lock(&console_owner_lock); - console_owner = current; - raw_spin_unlock(&console_owner_lock); + return (oops_in_progress || sync_mode); +} - /* The waiter may spin on us after setting console_owner */ - spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_); +static bool console_may_sync(struct console *con) +{ + if (!(con->flags & CON_ENABLED)) + return false; + if (con->write_atomic && kernel_sync_mode()) + return true; + if (con->write_atomic && (con->flags & CON_HANDOVER) && !con->thread) + return true; + if (con->write && (con->flags & CON_BOOT) && !con->thread) + return true; + return false; } -/** - * console_lock_spinning_disable_and_check - mark end of code where another - * thread was able to busy wait and check if there is a waiter - * - * This is called at the end of the section where spinning is allowed. - * It has two functions. First, it is a signal that it is no longer - * safe to start busy waiting for the lock. Second, it checks if - * there is a busy waiter and passes the lock rights to her. - * - * Important: Callers lose the lock if there was a busy waiter. - * They must not touch items synchronized by console_lock - * in this case. - * - * Return: 1 if the lock rights were passed, 0 otherwise. - */ -static int console_lock_spinning_disable_and_check(void) +static bool call_sync_console_driver(struct console *con, const char *text, size_t text_len) { - int waiter; + if (!(con->flags & CON_ENABLED)) + return false; - raw_spin_lock(&console_owner_lock); - waiter = READ_ONCE(console_waiter); - console_owner = NULL; - raw_spin_unlock(&console_owner_lock); + if (con->write_atomic && kernel_sync_mode()) { + con->write_atomic(con, text, text_len); + return true; + } - if (!waiter) { - spin_release(&console_owner_dep_map, _THIS_IP_); - return 0; + if (con->write_atomic && (con->flags & CON_HANDOVER) && !con->thread) { + if (console_trylock()) { + con->write_atomic(con, text, text_len); + console_unlock(); + return true; + } + + } else if (con->write && (con->flags & CON_BOOT) && !con->thread) { + if (console_trylock()) { + con->write(con, text, text_len); + console_unlock(); + return true; + } } - /* The waiter is now free to continue */ - WRITE_ONCE(console_waiter, false); + return false; +} - spin_release(&console_owner_dep_map, _THIS_IP_); +static bool have_atomic_console(void) +{ + struct console *con; - /* - * Hand off console_lock to waiter. The waiter will perform - * the up(). After this, the waiter is the console_lock owner. - */ - mutex_release(&console_lock_dep_map, _THIS_IP_); - return 1; + for_each_console(con) { + if (!(con->flags & CON_ENABLED)) + continue; + if (con->write_atomic) + return true; + } + return false; } -/** - * console_trylock_spinning - try to get console_lock by busy waiting - * - * This allows to busy wait for the console_lock when the current - * owner is running in specially marked sections. It means that - * the current owner is running and cannot reschedule until it - * is ready to lose the lock. - * - * Return: 1 if we got the lock, 0 othrewise - */ -static int console_trylock_spinning(void) +static bool print_sync(struct console *con, u64 *seq) { - struct task_struct *owner = NULL; - bool waiter; - bool spin = false; - unsigned long flags; + struct printk_info info; + struct printk_record r; + size_t text_len; - if (console_trylock()) - return 1; + prb_rec_init_rd(&r, &info, &con->sync_buf[0], sizeof(con->sync_buf)); - printk_safe_enter_irqsave(flags); + if (!prb_read_valid(prb, *seq, &r)) + return false; - raw_spin_lock(&console_owner_lock); - owner = READ_ONCE(console_owner); - waiter = READ_ONCE(console_waiter); - if (!waiter && owner && owner != current) { - WRITE_ONCE(console_waiter, true); - spin = true; - } - raw_spin_unlock(&console_owner_lock); + text_len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time); - /* - * If there is an active printk() writing to the - * consoles, instead of having it write our data too, - * see if we can offload that load from the active - * printer, and do some printing ourselves. - * Go into a spin only if there isn't already a waiter - * spinning, and there is an active printer, and - * that active printer isn't us (recursive printk?). - */ - if (!spin) { - printk_safe_exit_irqrestore(flags); - return 0; - } + if (!call_sync_console_driver(con, &con->sync_buf[0], text_len)) + return false; - /* We spin waiting for the owner to release us */ - spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_); - /* Owner will clear console_waiter on hand off */ - while (READ_ONCE(console_waiter)) - cpu_relax(); - spin_release(&console_owner_dep_map, _THIS_IP_); + *seq = r.info->seq; - printk_safe_exit_irqrestore(flags); - /* - * The owner passed the console lock to us. - * Since we did not spin on console lock, annotate - * this as a trylock. Otherwise lockdep will - * complain. - */ - mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_); + touch_softlockup_watchdog_sync(); + clocksource_touch_watchdog(); + rcu_cpu_stall_reset(); + touch_nmi_watchdog(); - return 1; + if (text_len) + printk_delay(r.info->level); + + return true; } -/* - * Call the console drivers, asking them to write out - * log_buf[start] to log_buf[end - 1]. - * The console_lock must be held. - */ -static void call_console_drivers(const char *ext_text, size_t ext_len, - const char *text, size_t len) +static u64 read_console_seq(struct console *con) { - static char dropped_text[64]; - size_t dropped_len = 0; - struct console *con; + u64 seq2; + u64 seq; - trace_console_rcuidle(text, len); + seq = latched_seq_read_nolock(&con->printk_seq); + seq2 = latched_seq_read_nolock(&con->printk_sync_seq); + if (seq2 > seq) + seq = seq2; +#ifdef CONFIG_HAVE_NMI + seq2 = latched_seq_read_nolock(&con->printk_sync_nmi_seq); + if (seq2 > seq) + seq = seq2; +#endif + return seq; +} - if (!console_drivers) - return; +static void print_sync_until(struct console *con, u64 seq, bool is_locked) +{ + u64 printk_seq; - if (console_dropped) { - dropped_len = snprintf(dropped_text, sizeof(dropped_text), - "** %lu printk messages dropped **\n", - console_dropped); - console_dropped = 0; - } + while (!__printk_cpu_trylock()) + cpu_relax(); - for_each_console(con) { - if (exclusive_console && con != exclusive_console) - continue; - if (!(con->flags & CON_ENABLED)) - continue; - if (!con->write) - continue; - if (!cpu_online(smp_processor_id()) && - !(con->flags & CON_ANYTIME)) - continue; - if (con->flags & CON_EXTENDED) - con->write(con, ext_text, ext_len); - else { - if (dropped_len) - con->write(con, dropped_text, dropped_len); - con->write(con, text, len); - } + for (;;) { + printk_seq = read_console_seq(con); + if (printk_seq >= seq) + break; + if (!print_sync(con, &printk_seq)) + break; + + if (is_locked) + latched_seq_write(&con->printk_seq, printk_seq + 1); +#ifdef CONFIG_PRINTK_NMI + else if (in_nmi()) + latched_seq_write(&con->printk_sync_nmi_seq, printk_seq + 1); +#endif + else + latched_seq_write(&con->printk_sync_seq, printk_seq + 1); } + + __printk_cpu_unlock(); } -int printk_delay_msec __read_mostly; +/* + * Recursion is tracked separately on each CPU. If NMIs are supported, an + * additional NMI context per CPU is also separately tracked. Until per-CPU + * is available, a separate "early tracking" is performed. + */ +static DEFINE_PER_CPU(u8, printk_count); +static u8 printk_count_early; +#ifdef CONFIG_HAVE_NMI +static DEFINE_PER_CPU(u8, printk_count_nmi); +static u8 printk_count_nmi_early; +#endif -static inline void printk_delay(void) -{ - if (unlikely(printk_delay_msec)) { - int m = printk_delay_msec; +/* + * Recursion is limited to keep the output sane. printk() should not require + * more than 1 level of recursion (allowing, for example, printk() to trigger + * a WARN), but a higher value is used in case some printk-internal errors + * exist, such as the ringbuffer validation checks failing. + */ +#define PRINTK_MAX_RECURSION 3 - while (m--) { - mdelay(1); - touch_nmi_watchdog(); - } +/* + * Return a pointer to the dedicated counter for the CPU+context of the + * caller. + */ +static u8 *__printk_recursion_counter(void) +{ +#ifdef CONFIG_HAVE_NMI + if (in_nmi()) { + if (printk_percpu_data_ready()) + return this_cpu_ptr(&printk_count_nmi); + return &printk_count_nmi_early; } +#endif + if (printk_percpu_data_ready()) + return this_cpu_ptr(&printk_count); + return &printk_count_early; } +/* + * Enter recursion tracking. Interrupts are disabled to simplify tracking. + * The caller must check the boolean return value to see if the recursion is + * allowed. On failure, interrupts are not disabled. + * + * @recursion_ptr must be a variable of type (u8 *) and is the same variable + * that is passed to printk_exit_irqrestore(). + */ +#define printk_enter_irqsave(recursion_ptr, flags) \ +({ \ + bool success = true; \ + \ + typecheck(u8 *, recursion_ptr); \ + local_irq_save(flags); \ + (recursion_ptr) = __printk_recursion_counter(); \ + if (*(recursion_ptr) > PRINTK_MAX_RECURSION) { \ + local_irq_restore(flags); \ + success = false; \ + } else { \ + (*(recursion_ptr))++; \ + } \ + success; \ +}) + +/* Exit recursion tracking, restoring interrupts. */ +#define printk_exit_irqrestore(recursion_ptr, flags) \ + do { \ + typecheck(u8 *, recursion_ptr); \ + (*(recursion_ptr))--; \ + local_irq_restore(flags); \ + } while (0) + static inline u32 printk_caller_id(void) { return in_task() ? task_pid_nr(current) : @@ -2032,20 +2019,25 @@ static u16 printk_sprint(char *text, u16 size, int facility, enum log_flags *lfl } __printf(4, 0) -int vprintk_store(int facility, int level, - const struct dev_printk_info *dev_info, - const char *fmt, va_list args) +static int vprintk_store(int facility, int level, + const struct dev_printk_info *dev_info, + const char *fmt, va_list args) { const u32 caller_id = printk_caller_id(); struct prb_reserved_entry e; enum log_flags lflags = 0; + bool final_commit = false; struct printk_record r; + unsigned long irqflags; u16 trunc_msg_len = 0; char prefix_buf[8]; + u8 *recursion_ptr; u16 reserve_size; va_list args2; u16 text_len; + int ret = 0; u64 ts_nsec; + u64 seq; /* * Since the duration of printk() can vary depending on the message @@ -2055,6 +2047,9 @@ int vprintk_store(int facility, int level, */ ts_nsec = local_clock(); + if (!printk_enter_irqsave(recursion_ptr, irqflags)) + return 0; + /* * The sprintf needs to come first since the syslog prefix might be * passed in as a parameter. An extra byte must be reserved so that @@ -2081,6 +2076,7 @@ int vprintk_store(int facility, int level, if (lflags & LOG_CONT) { prb_rec_init_wr(&r, reserve_size); if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) { + seq = r.info->seq; text_len = printk_sprint(&r.text_buf[r.info->text_len], reserve_size, facility, &lflags, fmt, args); r.info->text_len += text_len; @@ -2088,11 +2084,13 @@ int vprintk_store(int facility, int level, if (lflags & LOG_NEWLINE) { r.info->flags |= LOG_NEWLINE; prb_final_commit(&e); + final_commit = true; } else { prb_commit(&e); } - return text_len; + ret = text_len; + goto out; } } @@ -2108,9 +2106,11 @@ int vprintk_store(int facility, int level, prb_rec_init_wr(&r, reserve_size + trunc_msg_len); if (!prb_reserve(&e, prb, &r)) - return 0; + goto out; } + seq = r.info->seq; + /* fill message */ text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &lflags, fmt, args); if (trunc_msg_len) @@ -2125,12 +2125,27 @@ int vprintk_store(int facility, int level, memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info)); /* A message without a trailing newline can be continued. */ - if (!(lflags & LOG_NEWLINE)) + if (!(lflags & LOG_NEWLINE)) { prb_commit(&e); - else + } else { prb_final_commit(&e); + final_commit = true; + } + + ret = text_len + trunc_msg_len; +out: + /* only the kernel may perform synchronous printing */ + if (facility == 0 && final_commit) { + struct console *con; - return (text_len + trunc_msg_len); + for_each_console(con) { + if (console_may_sync(con)) + print_sync_until(con, seq + 1, false); + } + } + + printk_exit_irqrestore(recursion_ptr, irqflags); + return ret; } asmlinkage int vprintk_emit(int facility, int level, @@ -2138,53 +2153,43 @@ asmlinkage int vprintk_emit(int facility, int level, const char *fmt, va_list args) { int printed_len; - bool in_sched = false; - unsigned long flags; /* Suppress unimportant messages after panic happens */ if (unlikely(suppress_printk)) return 0; - if (level == LOGLEVEL_SCHED) { + if (level == LOGLEVEL_SCHED) level = LOGLEVEL_DEFAULT; - in_sched = true; - } - boot_delay_msec(level); - printk_delay(); - - printk_safe_enter_irqsave(flags); printed_len = vprintk_store(facility, level, dev_info, fmt, args); - printk_safe_exit_irqrestore(flags); - - /* If called from the scheduler, we can not call up(). */ - if (!in_sched) { - /* - * Disable preemption to avoid being preempted while holding - * console_sem which would prevent anyone from printing to - * console - */ - preempt_disable(); - /* - * Try to acquire and then immediately release the console - * semaphore. The release will print out buffers and wake up - * /dev/kmsg and syslog() users. - */ - if (console_trylock_spinning()) - console_unlock(); - preempt_enable(); - } wake_up_klogd(); return printed_len; } EXPORT_SYMBOL(vprintk_emit); -int vprintk_default(const char *fmt, va_list args) +__printf(1, 0) +static int vprintk_default(const char *fmt, va_list args) { return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args); } -EXPORT_SYMBOL_GPL(vprintk_default); + +__printf(1, 0) +static int vprintk_func(const char *fmt, va_list args) +{ +#ifdef CONFIG_KGDB_KDB + /* Allow to pass printk() to kdb but avoid a recursion. */ + if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0)) + return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); +#endif + return vprintk_default(fmt, args); +} + +asmlinkage int vprintk(const char *fmt, va_list args) +{ + return vprintk_func(fmt, args); +} +EXPORT_SYMBOL(vprintk); /** * printk - print a kernel message @@ -2220,38 +2225,163 @@ asmlinkage __visible int printk(const char *fmt, ...) } EXPORT_SYMBOL(printk); -#else /* CONFIG_PRINTK */ +static int printk_kthread_func(void *data) +{ + struct console *con = data; + unsigned long dropped = 0; + char *dropped_text = NULL; + struct printk_info info; + struct printk_record r; + char *ext_text = NULL; + size_t dropped_len; + int ret = -ENOMEM; + char *text = NULL; + char *write_text; + size_t len; + int error; + u64 seq; -#define CONSOLE_LOG_MAX 0 -#define printk_time false + if (con->flags & CON_EXTENDED) { + ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL); + if (!ext_text) + goto out; + } + text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); + dropped_text = kmalloc(64, GFP_KERNEL); + if (!text || !dropped_text) + goto out; -#define prb_read_valid(rb, seq, r) false -#define prb_first_valid_seq(rb) 0 + if (con->flags & CON_EXTENDED) + write_text = ext_text; + else + write_text = text; -static u64 syslog_seq; -static u64 console_seq; -static u64 exclusive_console_stop_seq; -static unsigned long console_dropped; + seq = read_console_seq(con); -static size_t record_print_text(const struct printk_record *r, - bool syslog, bool time) -{ - return 0; + prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX); + + for (;;) { + error = wait_event_interruptible(log_wait, + prb_read_valid(prb, seq, &r) || kthread_should_stop()); + + if (kthread_should_stop()) + break; + + if (error) + continue; + + if (seq != r.info->seq) { + dropped += r.info->seq - seq; + seq = r.info->seq; + } + + seq++; + + if (!(con->flags & CON_ENABLED)) + continue; + + if (suppress_message_printing(r.info->level)) + continue; + + if (con->flags & CON_EXTENDED) { + len = info_print_ext_header(ext_text, + CONSOLE_EXT_LOG_MAX, + r.info); + len += msg_print_ext_body(ext_text + len, + CONSOLE_EXT_LOG_MAX - len, + &r.text_buf[0], r.info->text_len, + &r.info->dev_info); + } else { + len = record_print_text(&r, + console_msg_format & MSG_FORMAT_SYSLOG, + printk_time); + } + + console_lock(); + + /* + * Even though the printk kthread is always preemptible, it is + * still not allowed to call cond_resched() from within + * console drivers. The task may become non-preemptible in the + * console driver call chain. For example, vt_console_print() + * takes a spinlock and then can call into fbcon_redraw(), + * which can conditionally invoke cond_resched(). + */ + console_may_schedule = 0; + + if (kernel_sync_mode() && con->write_atomic) { + console_unlock(); + break; + } + + if (!(con->flags & CON_EXTENDED) && dropped) { + dropped_len = snprintf(dropped_text, 64, + "** %lu printk messages dropped **\n", + dropped); + dropped = 0; + + con->write(con, dropped_text, dropped_len); + printk_delay(r.info->level); + } + + con->write(con, write_text, len); + if (len) + printk_delay(r.info->level); + + latched_seq_write(&con->printk_seq, seq); + + console_unlock(); + } + ret = 0; +out: + kfree(dropped_text); + kfree(text); + kfree(ext_text); + pr_info("%sconsole [%s%d]: printing thread stopped\n", + (con->flags & CON_BOOT) ? "boot" : "", + con->name, con->index); + return ret; } -static ssize_t info_print_ext_header(char *buf, size_t size, - struct printk_info *info) + +/* Must be called within console_lock(). */ +static void start_printk_kthread(struct console *con) { - return 0; + con->thread = kthread_run(printk_kthread_func, con, + "pr/%s%d", con->name, con->index); + if (IS_ERR(con->thread)) { + pr_err("%sconsole [%s%d]: unable to start printing thread\n", + (con->flags & CON_BOOT) ? "boot" : "", + con->name, con->index); + return; + } + pr_info("%sconsole [%s%d]: printing thread started\n", + (con->flags & CON_BOOT) ? "boot" : "", + con->name, con->index); } -static ssize_t msg_print_ext_body(char *buf, size_t size, - char *text, size_t text_len, - struct dev_printk_info *dev_info) { return 0; } -static void console_lock_spinning_enable(void) { } -static int console_lock_spinning_disable_and_check(void) { return 0; } -static void call_console_drivers(const char *ext_text, size_t ext_len, - const char *text, size_t len) {} -static bool suppress_message_printing(int level) { return false; } +/* protected by console_lock */ +static bool kthreads_started; + +/* Must be called within console_lock(). */ +static void console_try_thread(struct console *con) +{ + if (kthreads_started) { + start_printk_kthread(con); + return; + } + + /* + * The printing threads have not been started yet. If this console + * can print synchronously, print all unprinted messages. + */ + if (console_may_sync(con)) { + unsigned long flags; + + local_irq_save(flags); + print_sync_until(con, prb_next_seq(prb), true); + local_irq_restore(flags); + } +} #endif /* CONFIG_PRINTK */ #ifdef CONFIG_EARLY_PRINTK @@ -2495,34 +2625,6 @@ int is_console_locked(void) } EXPORT_SYMBOL(is_console_locked); -/* - * Check if we have any console that is capable of printing while cpu is - * booting or shutting down. Requires console_sem. - */ -static int have_callable_console(void) -{ - struct console *con; - - for_each_console(con) - if ((con->flags & CON_ENABLED) && - (con->flags & CON_ANYTIME)) - return 1; - - return 0; -} - -/* - * Can we actually use the console at this time on this cpu? - * - * Console drivers may assume that per-cpu resources have been allocated. So - * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't - * call them until this CPU is officially up. - */ -static inline int can_use_console(void) -{ - return cpu_online(raw_smp_processor_id()) || have_callable_console(); -} - /** * console_unlock - unlock the console system * @@ -2539,139 +2641,13 @@ static inline int can_use_console(void) */ void console_unlock(void) { - static char ext_text[CONSOLE_EXT_LOG_MAX]; - static char text[CONSOLE_LOG_MAX]; - unsigned long flags; - bool do_cond_resched, retry; - struct printk_info info; - struct printk_record r; - u64 __maybe_unused next_seq; - if (console_suspended) { up_console_sem(); return; } - prb_rec_init_rd(&r, &info, text, sizeof(text)); - - /* - * Console drivers are called with interrupts disabled, so - * @console_may_schedule should be cleared before; however, we may - * end up dumping a lot of lines, for example, if called from - * console registration path, and should invoke cond_resched() - * between lines if allowable. Not doing so can cause a very long - * scheduling stall on a slow console leading to RCU stall and - * softlockup warnings which exacerbate the issue with more - * messages practically incapacitating the system. - * - * console_trylock() is not able to detect the preemptive - * context reliably. Therefore the value must be stored before - * and cleared after the "again" goto label. - */ - do_cond_resched = console_may_schedule; -again: - console_may_schedule = 0; - - /* - * We released the console_sem lock, so we need to recheck if - * cpu is online and (if not) is there at least one CON_ANYTIME - * console. - */ - if (!can_use_console()) { - console_locked = 0; - up_console_sem(); - return; - } - - for (;;) { - size_t ext_len = 0; - size_t len; - - printk_safe_enter_irqsave(flags); -skip: - if (!prb_read_valid(prb, console_seq, &r)) - break; - - if (console_seq != r.info->seq) { - console_dropped += r.info->seq - console_seq; - console_seq = r.info->seq; - } - - if (suppress_message_printing(r.info->level)) { - /* - * Skip record we have buffered and already printed - * directly to the console when we received it, and - * record that has level above the console loglevel. - */ - console_seq++; - goto skip; - } - - /* Output to all consoles once old messages replayed. */ - if (unlikely(exclusive_console && - console_seq >= exclusive_console_stop_seq)) { - exclusive_console = NULL; - } - - /* - * Handle extended console text first because later - * record_print_text() will modify the record buffer in-place. - */ - if (nr_ext_console_drivers) { - ext_len = info_print_ext_header(ext_text, - sizeof(ext_text), - r.info); - ext_len += msg_print_ext_body(ext_text + ext_len, - sizeof(ext_text) - ext_len, - &r.text_buf[0], - r.info->text_len, - &r.info->dev_info); - } - len = record_print_text(&r, - console_msg_format & MSG_FORMAT_SYSLOG, - printk_time); - console_seq++; - - /* - * While actively printing out messages, if another printk() - * were to occur on another CPU, it may wait for this one to - * finish. This task can not be preempted if there is a - * waiter waiting to take over. - */ - console_lock_spinning_enable(); - - stop_critical_timings(); /* don't trace print latency */ - call_console_drivers(ext_text, ext_len, text, len); - start_critical_timings(); - - if (console_lock_spinning_disable_and_check()) { - printk_safe_exit_irqrestore(flags); - return; - } - - printk_safe_exit_irqrestore(flags); - - if (do_cond_resched) - cond_resched(); - } - - /* Get consistent value of the next-to-be-used sequence number. */ - next_seq = console_seq; - console_locked = 0; up_console_sem(); - - /* - * Someone could have filled up the buffer again, so re-check if there's - * something to flush. In case we cannot trylock the console_sem again, - * there's a new owner and the console_unlock() from them will do the - * flush, no worries. - */ - retry = prb_read_valid(prb, next_seq, NULL); - printk_safe_exit_irqrestore(flags); - - if (retry && console_trylock()) - goto again; } EXPORT_SYMBOL(console_unlock); @@ -2721,23 +2697,20 @@ void console_unblank(void) */ void console_flush_on_panic(enum con_flush_mode mode) { - /* - * If someone else is holding the console lock, trylock will fail - * and may_schedule may be set. Ignore and proceed to unlock so - * that messages are flushed out. As this can be called from any - * context and we don't want to get preempted while flushing, - * ensure may_schedule is cleared. - */ - console_trylock(); - console_may_schedule = 0; + if (!console_trylock()) + return; +#ifdef CONFIG_PRINTK if (mode == CONSOLE_REPLAY_ALL) { - unsigned long flags; + struct console *c; + u64 seq; - printk_safe_enter_irqsave(flags); - console_seq = prb_first_valid_seq(prb); - printk_safe_exit_irqrestore(flags); + seq = prb_first_valid_seq(prb); + for_each_console(c) + latched_seq_write(&c->printk_seq, seq); } +#endif + console_unlock(); } @@ -2872,8 +2845,8 @@ static int try_enable_new_console(struct console *newcon, bool user_specified) */ void register_console(struct console *newcon) { - unsigned long flags; struct console *bcon = NULL; + u64 __maybe_unused seq = 0; int err; for_each_console(bcon) { @@ -2896,6 +2869,8 @@ void register_console(struct console *newcon) } } + newcon->thread = NULL; + if (console_drivers && console_drivers->flags & CON_BOOT) bcon = console_drivers; @@ -2937,8 +2912,10 @@ void register_console(struct console *newcon) * the real console are the same physical device, it's annoying to * see the beginning boot messages twice */ - if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) + if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) { newcon->flags &= ~CON_PRINTBUFFER; + newcon->flags |= CON_HANDOVER; + } /* * Put this console in the list - keep the @@ -2960,27 +2937,21 @@ void register_console(struct console *newcon) if (newcon->flags & CON_EXTENDED) nr_ext_console_drivers++; - if (newcon->flags & CON_PRINTBUFFER) { - /* - * console_unlock(); will print out the buffered messages - * for us. - * - * We're about to replay the log buffer. Only do this to the - * just-registered console to avoid excessive message spam to - * the already-registered consoles. - * - * Set exclusive_console with disabled interrupts to reduce - * race window with eventual console_flush_on_panic() that - * ignores console_lock. - */ - exclusive_console = newcon; - exclusive_console_stop_seq = console_seq; +#ifdef CONFIG_PRINTK + if (!(newcon->flags & CON_PRINTBUFFER)) + seq = prb_next_seq(prb); + + seqcount_latch_init(&newcon->printk_seq.latch); + latched_seq_write(&newcon->printk_seq, seq); + seqcount_latch_init(&newcon->printk_sync_seq.latch); + latched_seq_write(&newcon->printk_sync_seq, seq); +#ifdef CONFIG_HAVE_NMI + seqcount_latch_init(&newcon->printk_sync_nmi_seq.latch); + latched_seq_write(&newcon->printk_sync_nmi_seq, seq); +#endif - /* Get a consistent copy of @syslog_seq. */ - raw_spin_lock_irqsave(&syslog_lock, flags); - console_seq = syslog_seq; - raw_spin_unlock_irqrestore(&syslog_lock, flags); - } + console_try_thread(newcon); +#endif /* CONFIG_PRINTK */ console_unlock(); console_sysfs_notify(); @@ -3054,6 +3025,9 @@ int unregister_console(struct console *console) console_unlock(); console_sysfs_notify(); + if (console->thread && !IS_ERR(console->thread)) + kthread_stop(console->thread); + if (console->exit) res = console->exit(console); @@ -3136,6 +3110,15 @@ static int __init printk_late_init(void) unregister_console(con); } } + +#ifdef CONFIG_PRINTK + console_lock(); + for_each_console(con) + start_printk_kthread(con); + kthreads_started = true; + console_unlock(); +#endif + ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, console_cpu_notify); WARN_ON(ret < 0); @@ -3151,7 +3134,6 @@ late_initcall(printk_late_init); * Delayed printk version, for scheduler-internal messages: */ #define PRINTK_PENDING_WAKEUP 0x01 -#define PRINTK_PENDING_OUTPUT 0x02 static DEFINE_PER_CPU(int, printk_pending); @@ -3159,14 +3141,8 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work) { int pending = __this_cpu_xchg(printk_pending, 0); - if (pending & PRINTK_PENDING_OUTPUT) { - /* If trylock fails, someone else is doing the printing */ - if (console_trylock()) - console_unlock(); - } - if (pending & PRINTK_PENDING_WAKEUP) - wake_up_interruptible(&log_wait); + wake_up_interruptible_all(&log_wait); } static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = @@ -3185,39 +3161,6 @@ void wake_up_klogd(void) preempt_enable(); } -void defer_console_output(void) -{ - if (!printk_percpu_data_ready()) - return; - - preempt_disable(); - __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); - irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); - preempt_enable(); -} - -int vprintk_deferred(const char *fmt, va_list args) -{ - int r; - - r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, fmt, args); - defer_console_output(); - - return r; -} - -int printk_deferred(const char *fmt, ...) -{ - va_list args; - int r; - - va_start(args, fmt); - r = vprintk_deferred(fmt, args); - va_end(args); - - return r; -} - /* * printk rate limiting, lifted from the networking subsystem. * @@ -3344,6 +3287,24 @@ void kmsg_dump(enum kmsg_dump_reason reason) { struct kmsg_dumper *dumper; + if (!oops_in_progress) { + /* + * If atomic consoles are available, activate kernel sync mode + * to make sure any final messages are visible. The trailing + * printk message is important to flush any pending messages. + */ + if (have_atomic_console()) { + sync_mode = true; + pr_info("enabled sync mode\n"); + } + + /* + * Give the printing threads time to flush, allowing up to + * 1s of no printing forward progress before giving up. + */ + pr_flush(1000, true); + } + rcu_read_lock(); list_for_each_entry_rcu(dumper, &dump_list, list) { enum kmsg_dump_reason max_reason = dumper->max_reason; @@ -3389,14 +3350,12 @@ bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, struct printk_info info; unsigned int line_count; struct printk_record r; - unsigned long flags; size_t l = 0; bool ret = false; if (iter->cur_seq < min_seq) iter->cur_seq = min_seq; - printk_safe_enter_irqsave(flags); prb_rec_init_rd(&r, &info, line, size); /* Read text or count text lines? */ @@ -3417,7 +3376,6 @@ bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog, iter->cur_seq = r.info->seq + 1; ret = true; out: - printk_safe_exit_irqrestore(flags); if (len) *len = l; return ret; @@ -3449,7 +3407,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, u64 min_seq = latched_seq_read_nolock(&clear_seq); struct printk_info info; struct printk_record r; - unsigned long flags; u64 seq; u64 next_seq; size_t len = 0; @@ -3462,7 +3419,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, if (iter->cur_seq < min_seq) iter->cur_seq = min_seq; - printk_safe_enter_irqsave(flags); if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) { if (info.seq != iter->cur_seq) { /* messages are gone, move to first available one */ @@ -3471,10 +3427,8 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, } /* last entry */ - if (iter->cur_seq >= iter->next_seq) { - printk_safe_exit_irqrestore(flags); + if (iter->cur_seq >= iter->next_seq) goto out; - } /* * Find first record that fits, including all following records, @@ -3506,7 +3460,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog, iter->next_seq = next_seq; ret = true; - printk_safe_exit_irqrestore(flags); out: if (len_out) *len_out = len; @@ -3524,12 +3477,8 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); */ void kmsg_dump_rewind(struct kmsg_dump_iter *iter) { - unsigned long flags; - - printk_safe_enter_irqsave(flags); iter->cur_seq = latched_seq_read_nolock(&clear_seq); iter->next_seq = prb_next_seq(prb); - printk_safe_exit_irqrestore(flags); } EXPORT_SYMBOL_GPL(kmsg_dump_rewind); @@ -3538,6 +3487,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_rewind); #ifdef CONFIG_SMP static atomic_t printk_cpulock_owner = ATOMIC_INIT(-1); static atomic_t printk_cpulock_nested = ATOMIC_INIT(0); +static unsigned int kgdb_cpu = -1; /** * __printk_wait_on_cpu_lock() - Busy wait until the printk cpu-reentrant @@ -3617,6 +3567,9 @@ EXPORT_SYMBOL(__printk_cpu_trylock); */ void __printk_cpu_unlock(void) { + bool trigger_kgdb = false; + unsigned int cpu; + if (atomic_read(&printk_cpulock_nested)) { atomic_dec(&printk_cpulock_nested); return; @@ -3627,6 +3580,12 @@ void __printk_cpu_unlock(void) * LMM(__printk_cpu_unlock:A) */ + cpu = smp_processor_id(); + if (kgdb_cpu == cpu) { + trigger_kgdb = true; + kgdb_cpu = -1; + } + /* * Guarantee loads and stores from this CPU when it was the * lock owner are visible to the next lock owner. This pairs @@ -3647,6 +3606,98 @@ void __printk_cpu_unlock(void) */ atomic_set_release(&printk_cpulock_owner, -1); /* LMM(__printk_cpu_unlock:B) */ + + if (trigger_kgdb) { + pr_warn("re-triggering kgdb roundup for CPU#%d\n", cpu); + kgdb_roundup_cpu(cpu); + } } EXPORT_SYMBOL(__printk_cpu_unlock); + +bool kgdb_roundup_delay(unsigned int cpu) +{ + if (cpu != atomic_read(&printk_cpulock_owner)) + return false; + + kgdb_cpu = cpu; + return true; +} +EXPORT_SYMBOL(kgdb_roundup_delay); #endif /* CONFIG_SMP */ + +#ifdef CONFIG_PRINTK +static void pr_msleep(bool may_sleep, int ms) +{ + if (may_sleep) { + msleep(ms); + } else { + while (ms--) + udelay(1000); + } +} + +/** + * pr_flush() - Wait for printing threads to catch up. + * + * @timeout_ms: The maximum time (in ms) to wait. + * @reset_on_progress: Reset the timeout if forward progress is seen. + * + * A value of 0 for @timeout_ms means no waiting will occur. A value of -1 + * represents infinite waiting. + * + * If @reset_on_progress is true, the timeout will be reset whenever any + * printer has been seen to make some forward progress. + * + * Context: Any context. + * Return: true if all enabled printers are caught up. + */ +bool pr_flush(int timeout_ms, bool reset_on_progress) +{ + int remaining = timeout_ms; + struct console *con; + u64 last_diff = 0; + bool may_sleep; + u64 printk_seq; + u64 diff; + u64 seq; + + may_sleep = (preemptible() && + !in_softirq() && + system_state >= SYSTEM_RUNNING); + + seq = prb_next_seq(prb); + + for (;;) { + diff = 0; + + for_each_console(con) { + if (!(con->flags & CON_ENABLED)) + continue; + printk_seq = read_console_seq(con); + if (printk_seq < seq) + diff += seq - printk_seq; + } + + if (diff != last_diff && reset_on_progress) + remaining = timeout_ms; + + if (diff == 0 || remaining == 0) + break; + + if (remaining < 0) { + pr_msleep(may_sleep, 100); + } else if (remaining < 100) { + pr_msleep(may_sleep, remaining); + remaining = 0; + } else { + pr_msleep(may_sleep, 100); + remaining -= 100; + } + + last_diff = diff; + } + + return (diff == 0); +} +EXPORT_SYMBOL(pr_flush); +#endif /* CONFIG_PRINTK */ diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c deleted file mode 100644 index 94232186fccb..000000000000 --- a/kernel/printk/printk_safe.c +++ /dev/null @@ -1,414 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * printk_safe.c - Safe printk for printk-deadlock-prone contexts - */ - -#include <linux/preempt.h> -#include <linux/spinlock.h> -#include <linux/debug_locks.h> -#include <linux/kdb.h> -#include <linux/smp.h> -#include <linux/cpumask.h> -#include <linux/irq_work.h> -#include <linux/printk.h> -#include <linux/kprobes.h> - -#include "internal.h" - -/* - * In NMI and safe mode, printk() avoids taking locks. Instead, - * it uses an alternative implementation that temporary stores - * the strings into a per-CPU buffer. The content of the buffer - * is later flushed into the main ring buffer via IRQ work. - * - * The alternative implementation is chosen transparently - * by examining current printk() context mask stored in @printk_context - * per-CPU variable. - * - * The implementation allows to flush the strings also from another CPU. - * There are situations when we want to make sure that all buffers - * were handled or when IRQs are blocked. - */ - -#define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) - \ - sizeof(atomic_t) - \ - sizeof(atomic_t) - \ - sizeof(struct irq_work)) - -struct printk_safe_seq_buf { - atomic_t len; /* length of written data */ - atomic_t message_lost; - struct irq_work work; /* IRQ work that flushes the buffer */ - unsigned char buffer[SAFE_LOG_BUF_LEN]; -}; - -static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq); -static DEFINE_PER_CPU(int, printk_context); - -static DEFINE_RAW_SPINLOCK(safe_read_lock); - -#ifdef CONFIG_PRINTK_NMI -static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq); -#endif - -/* Get flushed in a more safe context. */ -static void queue_flush_work(struct printk_safe_seq_buf *s) -{ - if (printk_percpu_data_ready()) - irq_work_queue(&s->work); -} - -/* - * Add a message to per-CPU context-dependent buffer. NMI and printk-safe - * have dedicated buffers, because otherwise printk-safe preempted by - * NMI-printk would have overwritten the NMI messages. - * - * The messages are flushed from irq work (or from panic()), possibly, - * from other CPU, concurrently with printk_safe_log_store(). Should this - * happen, printk_safe_log_store() will notice the buffer->len mismatch - * and repeat the write. - */ -static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s, - const char *fmt, va_list args) -{ - int add; - size_t len; - va_list ap; - -again: - len = atomic_read(&s->len); - - /* The trailing '\0' is not counted into len. */ - if (len >= sizeof(s->buffer) - 1) { - atomic_inc(&s->message_lost); - queue_flush_work(s); - return 0; - } - - /* - * Make sure that all old data have been read before the buffer - * was reset. This is not needed when we just append data. - */ - if (!len) - smp_rmb(); - - va_copy(ap, args); - add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap); - va_end(ap); - if (!add) - return 0; - - /* - * Do it once again if the buffer has been flushed in the meantime. - * Note that atomic_cmpxchg() is an implicit memory barrier that - * makes sure that the data were written before updating s->len. - */ - if (atomic_cmpxchg(&s->len, len, len + add) != len) - goto again; - - queue_flush_work(s); - return add; -} - -static inline void printk_safe_flush_line(const char *text, int len) -{ - /* - * Avoid any console drivers calls from here, because we may be - * in NMI or printk_safe context (when in panic). The messages - * must go only into the ring buffer at this stage. Consoles will - * get explicitly called later when a crashdump is not generated. - */ - printk_deferred("%.*s", len, text); -} - -/* printk part of the temporary buffer line by line */ -static int printk_safe_flush_buffer(const char *start, size_t len) -{ - const char *c, *end; - bool header; - - c = start; - end = start + len; - header = true; - - /* Print line by line. */ - while (c < end) { - if (*c == '\n') { - printk_safe_flush_line(start, c - start + 1); - start = ++c; - header = true; - continue; - } - - /* Handle continuous lines or missing new line. */ - if ((c + 1 < end) && printk_get_level(c)) { - if (header) { - c = printk_skip_level(c); - continue; - } - - printk_safe_flush_line(start, c - start); - start = c++; - header = true; - continue; - } - - header = false; - c++; - } - - /* Check if there was a partial line. Ignore pure header. */ - if (start < end && !header) { - static const char newline[] = KERN_CONT "\n"; - - printk_safe_flush_line(start, end - start); - printk_safe_flush_line(newline, strlen(newline)); - } - - return len; -} - -static void report_message_lost(struct printk_safe_seq_buf *s) -{ - int lost = atomic_xchg(&s->message_lost, 0); - - if (lost) - printk_deferred("Lost %d message(s)!\n", lost); -} - -/* - * Flush data from the associated per-CPU buffer. The function - * can be called either via IRQ work or independently. - */ -static void __printk_safe_flush(struct irq_work *work) -{ - struct printk_safe_seq_buf *s = - container_of(work, struct printk_safe_seq_buf, work); - unsigned long flags; - size_t len; - int i; - - /* - * The lock has two functions. First, one reader has to flush all - * available message to make the lockless synchronization with - * writers easier. Second, we do not want to mix messages from - * different CPUs. This is especially important when printing - * a backtrace. - */ - raw_spin_lock_irqsave(&safe_read_lock, flags); - - i = 0; -more: - len = atomic_read(&s->len); - - /* - * This is just a paranoid check that nobody has manipulated - * the buffer an unexpected way. If we printed something then - * @len must only increase. Also it should never overflow the - * buffer size. - */ - if ((i && i >= len) || len > sizeof(s->buffer)) { - const char *msg = "printk_safe_flush: internal error\n"; - - printk_safe_flush_line(msg, strlen(msg)); - len = 0; - } - - if (!len) - goto out; /* Someone else has already flushed the buffer. */ - - /* Make sure that data has been written up to the @len */ - smp_rmb(); - i += printk_safe_flush_buffer(s->buffer + i, len - i); - - /* - * Check that nothing has got added in the meantime and truncate - * the buffer. Note that atomic_cmpxchg() is an implicit memory - * barrier that makes sure that the data were copied before - * updating s->len. - */ - if (atomic_cmpxchg(&s->len, len, 0) != len) - goto more; - -out: - report_message_lost(s); - raw_spin_unlock_irqrestore(&safe_read_lock, flags); -} - -/** - * printk_safe_flush - flush all per-cpu nmi buffers. - * - * The buffers are flushed automatically via IRQ work. This function - * is useful only when someone wants to be sure that all buffers have - * been flushed at some point. - */ -void printk_safe_flush(void) -{ - int cpu; - - for_each_possible_cpu(cpu) { -#ifdef CONFIG_PRINTK_NMI - __printk_safe_flush(&per_cpu(nmi_print_seq, cpu).work); -#endif - __printk_safe_flush(&per_cpu(safe_print_seq, cpu).work); - } -} - -/** - * printk_safe_flush_on_panic - flush all per-cpu nmi buffers when the system - * goes down. - * - * Similar to printk_safe_flush() but it can be called even in NMI context when - * the system goes down. It does the best effort to get NMI messages into - * the main ring buffer. - * - * Note that it could try harder when there is only one CPU online. - */ -void printk_safe_flush_on_panic(void) -{ - /* - * Make sure that we could access the safe buffers. - * Do not risk a double release when more CPUs are up. - */ - if (raw_spin_is_locked(&safe_read_lock)) { - if (num_online_cpus() > 1) - return; - - debug_locks_off(); - raw_spin_lock_init(&safe_read_lock); - } - - printk_safe_flush(); -} - -#ifdef CONFIG_PRINTK_NMI -/* - * Safe printk() for NMI context. It uses a per-CPU buffer to - * store the message. NMIs are not nested, so there is always only - * one writer running. But the buffer might get flushed from another - * CPU, so we need to be careful. - */ -static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) -{ - struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq); - - return printk_safe_log_store(s, fmt, args); -} - -void noinstr printk_nmi_enter(void) -{ - this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET); -} - -void noinstr printk_nmi_exit(void) -{ - this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET); -} - -/* - * Marks a code that might produce many messages in NMI context - * and the risk of losing them is more critical than eventual - * reordering. - * - * It has effect only when called in NMI context. Then printk() - * will store the messages into the main logbuf directly. - */ -void printk_nmi_direct_enter(void) -{ - if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK) - this_cpu_or(printk_context, PRINTK_NMI_DIRECT_CONTEXT_MASK); -} - -void printk_nmi_direct_exit(void) -{ - this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK); -} - -#else - -static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) -{ - return 0; -} - -#endif /* CONFIG_PRINTK_NMI */ - -/* - * Lock-less printk(), to avoid deadlocks should the printk() recurse - * into itself. It uses a per-CPU buffer to store the message, just like - * NMI. - */ -static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args) -{ - struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq); - - return printk_safe_log_store(s, fmt, args); -} - -/* Can be preempted by NMI. */ -void __printk_safe_enter(void) -{ - this_cpu_inc(printk_context); -} - -/* Can be preempted by NMI. */ -void __printk_safe_exit(void) -{ - this_cpu_dec(printk_context); -} - -asmlinkage int vprintk(const char *fmt, va_list args) -{ -#ifdef CONFIG_KGDB_KDB - /* Allow to pass printk() to kdb but avoid a recursion. */ - if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0)) - return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); -#endif - - /* - * Use the main logbuf even in NMI. But avoid calling console - * drivers that might have their own locks. - */ - if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) { - unsigned long flags; - int len; - - printk_safe_enter_irqsave(flags); - len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, fmt, args); - printk_safe_exit_irqrestore(flags); - defer_console_output(); - return len; - } - - /* Use extra buffer in NMI. */ - if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK) - return vprintk_nmi(fmt, args); - - /* Use extra buffer to prevent a recursion deadlock in safe mode. */ - if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK) - return vprintk_safe(fmt, args); - - /* No obstacles. */ - return vprintk_default(fmt, args); -} -EXPORT_SYMBOL(vprintk); - -void __init printk_safe_init(void) -{ - int cpu; - - for_each_possible_cpu(cpu) { - struct printk_safe_seq_buf *s; - - s = &per_cpu(safe_print_seq, cpu); - init_irq_work(&s->work, __printk_safe_flush); - -#ifdef CONFIG_PRINTK_NMI - s = &per_cpu(nmi_print_seq, cpu); - init_irq_work(&s->work, __printk_safe_flush); -#endif - } - - /* Flush pending messages that did not have scheduled IRQ works. */ - printk_safe_flush(); -} diff --git a/kernel/ptrace.c b/kernel/ptrace.c index f8589bf8d7dc..df08e8e64a83 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -197,7 +197,18 @@ static bool ptrace_freeze_traced(struct task_struct *task) spin_lock_irq(&task->sighand->siglock); if (task_is_traced(task) && !looks_like_a_spurious_pid(task) && !__fatal_signal_pending(task)) { +#ifdef CONFIG_PREEMPT_RT + unsigned long flags; + + raw_spin_lock_irqsave(&task->pi_lock, flags); + if (READ_ONCE(task->__state) & __TASK_TRACED) + WRITE_ONCE(task->__state, __TASK_TRACED); + else + task->saved_state = __TASK_TRACED; + raw_spin_unlock_irqrestore(&task->pi_lock, flags); +#else WRITE_ONCE(task->__state, __TASK_TRACED); +#endif ret = true; } spin_unlock_irq(&task->sighand->siglock); @@ -207,7 +218,11 @@ static bool ptrace_freeze_traced(struct task_struct *task) static void ptrace_unfreeze_traced(struct task_struct *task) { - if (READ_ONCE(task->__state) != __TASK_TRACED) + unsigned long flags; + bool frozen = true; + + if (!IS_ENABLED(CONFIG_PREEMPT_RT) && + READ_ONCE(task->__state) != __TASK_TRACED) return; WARN_ON(!task->ptrace || task->parent != current); @@ -217,12 +232,21 @@ static void ptrace_unfreeze_traced(struct task_struct *task) * Recheck state under the lock to close this race. */ spin_lock_irq(&task->sighand->siglock); - if (READ_ONCE(task->__state) == __TASK_TRACED) { - if (__fatal_signal_pending(task)) - wake_up_state(task, __TASK_TRACED); - else - WRITE_ONCE(task->__state, TASK_TRACED); - } + raw_spin_lock_irqsave(&task->pi_lock, flags); + if (READ_ONCE(task->__state) == __TASK_TRACED) + WRITE_ONCE(task->__state, TASK_TRACED); + +#ifdef CONFIG_PREEMPT_RT + else if (task->saved_state == __TASK_TRACED) + task->saved_state = TASK_TRACED; +#endif + else + frozen = false; + raw_spin_unlock_irqrestore(&task->pi_lock, flags); + + if (frozen && __fatal_signal_pending(task)) + wake_up_state(task, __TASK_TRACED); + spin_unlock_irq(&task->sighand->siglock); } diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index fd3909c59b6a..66d7e3c3706d 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1337,7 +1337,7 @@ static void test_rcu_tasks_callback(struct rcu_head *rhp) rttd->notrun = true; } -static void rcu_tasks_initiate_self_tests(void) +void rcu_tasks_initiate_self_tests(void) { pr_info("Running RCU-tasks wait API self tests\n"); #ifdef CONFIG_TASKS_RCU @@ -1374,9 +1374,7 @@ static int rcu_tasks_verify_self_tests(void) return ret; } late_initcall(rcu_tasks_verify_self_tests); -#else /* #ifdef CONFIG_PROVE_RCU */ -static void rcu_tasks_initiate_self_tests(void) { } -#endif /* #else #ifdef CONFIG_PROVE_RCU */ +#endif /* #ifdef CONFIG_PROVE_RCU */ void __init rcu_init_tasks_generic(void) { @@ -1391,9 +1389,6 @@ void __init rcu_init_tasks_generic(void) #ifdef CONFIG_TASKS_TRACE_RCU rcu_spawn_tasks_trace_kthread(); #endif - - // Run the self-tests. - rcu_tasks_initiate_self_tests(); } #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 51f24ecd94b2..caadfec994f3 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -87,6 +87,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = { .dynticks = ATOMIC_INIT(RCU_DYNTICK_CTRL_CTR), #ifdef CONFIG_RCU_NOCB_CPU .cblist.flags = SEGCBLIST_SOFTIRQ_ONLY, + .nocb_local_lock = INIT_LOCAL_LOCK(nocb_local_lock), #endif }; static struct rcu_state rcu_state = { @@ -2853,10 +2854,12 @@ static void rcu_cpu_kthread(unsigned int cpu) { unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_cpu_kthread_status); char work, *workp = this_cpu_ptr(&rcu_data.rcu_cpu_has_work); + struct rcu_data *rdp = this_cpu_ptr(&rcu_data); int spincnt; trace_rcu_utilization(TPS("Start CPU kthread@rcu_run")); for (spincnt = 0; spincnt < 10; spincnt++) { + rcu_nocb_local_lock(rdp); local_bh_disable(); *statusp = RCU_KTHREAD_RUNNING; local_irq_disable(); @@ -2866,6 +2869,7 @@ static void rcu_cpu_kthread(unsigned int cpu) if (work) rcu_core(); local_bh_enable(); + rcu_nocb_local_unlock(rdp); if (*workp == 0) { trace_rcu_utilization(TPS("End CPU kthread@rcu_wait")); *statusp = RCU_KTHREAD_WAITING; diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 305cf6aeb408..aa6831255fec 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -210,6 +210,8 @@ struct rcu_data { struct timer_list nocb_timer; /* Enforce finite deferral. */ unsigned long nocb_gp_adv_time; /* Last call_rcu() CB adv (jiffies). */ + local_lock_t nocb_local_lock; + /* The following fields are used by call_rcu, hence own cacheline. */ raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp; struct rcu_cblist nocb_bypass; /* Lock-contention-bypass CB list. */ @@ -445,6 +447,8 @@ static void rcu_nocb_unlock(struct rcu_data *rdp); static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp, unsigned long flags); static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp); +static void rcu_nocb_local_lock(struct rcu_data *rdp); +static void rcu_nocb_local_unlock(struct rcu_data *rdp); #ifdef CONFIG_RCU_NOCB_CPU static void __init rcu_organize_nocb_kthreads(void); #define rcu_nocb_lock_irqsave(rdp, flags) \ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 591e038e7670..ca75127f0c12 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -21,6 +21,11 @@ static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp) return lockdep_is_held(&rdp->nocb_lock); } +static inline int rcu_lockdep_is_held_nocb_local(struct rcu_data *rdp) +{ + return lockdep_is_held(&rdp->nocb_local_lock); +} + static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp) { /* Race on early boot between thread creation and assignment */ @@ -38,7 +43,10 @@ static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp) { return 0; } - +static inline int rcu_lockdep_is_held_nocb_local(struct rcu_data *rdp) +{ + return 0; +} static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp) { return false; @@ -46,23 +54,44 @@ static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp) #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ +/* + * Is a local read of the rdp's offloaded state safe and stable? + * See rcu_nocb_local_lock() & family. + */ +static inline bool rcu_local_offload_access_safe(struct rcu_data *rdp) +{ + if (!preemptible()) + return true; + + if (!is_migratable()) { + if (!IS_ENABLED(CONFIG_RCU_NOCB)) + return true; + + return rcu_lockdep_is_held_nocb_local(rdp); + } + + return false; +} + static bool rcu_rdp_is_offloaded(struct rcu_data *rdp) { /* - * In order to read the offloaded state of an rdp is a safe - * and stable way and prevent from its value to be changed - * under us, we must either hold the barrier mutex, the cpu - * hotplug lock (read or write) or the nocb lock. Local - * non-preemptible reads are also safe. NOCB kthreads and - * timers have their own means of synchronization against the - * offloaded state updaters. + * In order to read the offloaded state of an rdp is a safe and stable + * way and prevent from its value to be changed under us, we must either... */ RCU_LOCKDEP_WARN( + // ...hold the barrier mutex... !(lockdep_is_held(&rcu_state.barrier_mutex) || + // ... the cpu hotplug lock (read or write)... (IS_ENABLED(CONFIG_HOTPLUG_CPU) && lockdep_is_cpus_held()) || + // ... or the NOCB lock. rcu_lockdep_is_held_nocb(rdp) || + // Local reads still require the local state to remain stable + // (preemption disabled / local lock held) (rdp == this_cpu_ptr(&rcu_data) && - !(IS_ENABLED(CONFIG_PREEMPT_COUNT) && preemptible())) || + rcu_local_offload_access_safe(rdp)) || + // NOCB kthreads and timers have their own means of synchronization + // against the offloaded state updaters. rcu_current_is_nocb_kthread(rdp)), "Unsafe read of RCU_NOCB offloaded state" ); @@ -559,7 +588,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) WRITE_ONCE(rnp->exp_tasks, np); if (IS_ENABLED(CONFIG_RCU_BOOST)) { /* Snapshot ->boost_mtx ownership w/rnp->lock held. */ - drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t; + drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx.rtmutex) == t; if (&t->rcu_node_entry == rnp->boost_tasks) WRITE_ONCE(rnp->boost_tasks, np); } @@ -586,7 +615,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) /* Unboost if we were boosted. */ if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex) - rt_mutex_futex_unlock(&rnp->boost_mtx); + rt_mutex_futex_unlock(&rnp->boost_mtx.rtmutex); /* * If this was the last task on the expedited lists, @@ -1083,7 +1112,7 @@ static int rcu_boost(struct rcu_node *rnp) * section. */ t = container_of(tb, struct task_struct, rcu_node_entry); - rt_mutex_init_proxy_locked(&rnp->boost_mtx, t); + rt_mutex_init_proxy_locked(&rnp->boost_mtx.rtmutex, t); raw_spin_unlock_irqrestore_rcu_node(rnp, flags); /* Lock only for side effect: boosts task t's priority. */ rt_mutex_lock(&rnp->boost_mtx); @@ -1629,6 +1658,22 @@ static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp, } } +/* + * The invocation of rcu_core() within the RCU core kthreads remains preemptible + * under PREEMPT_RT, thus the offload state of a CPU could change while + * said kthreads are preempted. Prevent this from happening by protecting the + * offload state with a local_lock(). + */ +static void rcu_nocb_local_lock(struct rcu_data *rdp) +{ + local_lock(&rcu_data.nocb_local_lock); +} + +static void rcu_nocb_local_unlock(struct rcu_data *rdp) +{ + local_unlock(&rcu_data.nocb_local_lock); +} + /* Lockdep check that ->cblist may be safely accessed. */ static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp) { @@ -2396,6 +2441,7 @@ static int rdp_offload_toggle(struct rcu_data *rdp, if (rdp->nocb_cb_sleep) rdp->nocb_cb_sleep = false; rcu_nocb_unlock_irqrestore(rdp, flags); + rcu_nocb_local_unlock(rdp); /* * Ignore former value of nocb_cb_sleep and force wake up as it could @@ -2427,6 +2473,7 @@ static long rcu_nocb_rdp_deoffload(void *arg) pr_info("De-offloading %d\n", rdp->cpu); + rcu_nocb_local_lock(rdp); rcu_nocb_lock_irqsave(rdp, flags); /* * Flush once and for all now. This suffices because we are @@ -2509,6 +2556,7 @@ static long rcu_nocb_rdp_offload(void *arg) * Can't use rcu_nocb_lock_irqsave() while we are in * SEGCBLIST_SOFTIRQ_ONLY mode. */ + rcu_nocb_local_lock(rdp); raw_spin_lock_irqsave(&rdp->nocb_lock, flags); /* @@ -2868,6 +2916,16 @@ static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp, local_irq_restore(flags); } +/* No ->nocb_local_lock to acquire. */ +static void rcu_nocb_local_lock(struct rcu_data *rdp) +{ +} + +/* No ->nocb_local_lock to release. */ +static void rcu_nocb_local_unlock(struct rcu_data *rdp) +{ +} + /* Lockdep check that ->cblist may be safely accessed. */ static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp) { diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 9289da7f0ac4..889b3632d56d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -74,7 +74,11 @@ __read_mostly int sysctl_resched_latency_warn_once = 1; * Number of tasks to iterate in a single balance run. * Limited because this is done with IRQs disabled. */ +#ifdef CONFIG_PREEMPT_RT +const_debug unsigned int sysctl_sched_nr_migrate = 8; +#else const_debug unsigned int sysctl_sched_nr_migrate = 32; +#endif /* * period over which we measure -rt task CPU usage in us. @@ -982,6 +986,46 @@ void resched_curr(struct rq *rq) trace_sched_wake_idle_without_ipi(cpu); } +#ifdef CONFIG_PREEMPT_LAZY + +static int tsk_is_polling(struct task_struct *p) +{ +#ifdef TIF_POLLING_NRFLAG + return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG); +#else + return 0; +#endif +} + +void resched_curr_lazy(struct rq *rq) +{ + struct task_struct *curr = rq->curr; + int cpu; + + if (!sched_feat(PREEMPT_LAZY)) { + resched_curr(rq); + return; + } + + if (test_tsk_need_resched(curr)) + return; + + if (test_tsk_need_resched_lazy(curr)) + return; + + set_tsk_need_resched_lazy(curr); + + cpu = cpu_of(rq); + if (cpu == smp_processor_id()) + return; + + /* NEED_RESCHED_LAZY must be visible before we test polling */ + smp_mb(); + if (!tsk_is_polling(curr)) + smp_send_reschedule(cpu); +} +#endif + void resched_cpu(int cpu) { struct rq *rq = cpu_rq(cpu); @@ -2135,6 +2179,7 @@ void migrate_disable(void) preempt_disable(); this_rq()->nr_pinned++; p->migration_disabled = 1; + preempt_lazy_disable(); preempt_enable(); } EXPORT_SYMBOL_GPL(migrate_disable); @@ -2146,6 +2191,8 @@ void migrate_enable(void) if (p->migration_disabled > 1) { p->migration_disabled--; return; + } else if (WARN_ON_ONCE(p->migration_disabled == 0)) { + return; } /* @@ -2163,6 +2210,7 @@ void migrate_enable(void) barrier(); p->migration_disabled = 0; this_rq()->nr_pinned--; + preempt_lazy_enable(); preempt_enable(); } EXPORT_SYMBOL_GPL(migrate_enable); @@ -3011,7 +3059,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state * is actually now running somewhere else! */ while (task_running(rq, p)) { - if (match_state && unlikely(READ_ONCE(p->__state) != match_state)) + if (match_state && !task_match_state_lock(p, match_state)) return 0; cpu_relax(); } @@ -3026,7 +3074,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state running = task_running(rq, p); queued = task_on_rq_queued(p); ncsw = 0; - if (!match_state || READ_ONCE(p->__state) == match_state) + if (!match_state || task_match_state_or_saved(p, match_state)) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ task_rq_unlock(rq, p, &rf); @@ -3060,7 +3108,7 @@ unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state ktime_t to = NSEC_PER_SEC / HZ; set_current_state(TASK_UNINTERRUPTIBLE); - schedule_hrtimeout(&to, HRTIMER_MODE_REL); + schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD); continue; } @@ -3189,8 +3237,8 @@ out: * leave kernel. */ if (p->mm && printk_ratelimit()) { - printk_deferred("process %d (%s) no longer affine to cpu%d\n", - task_pid_nr(p), p->comm, cpu); + printk("process %d (%s) no longer affine to cpu%d\n", + task_pid_nr(p), p->comm, cpu); } } @@ -3589,6 +3637,55 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) } /* + * Invoked from try_to_wake_up() to check whether the task can be woken up. + * + * The caller holds p::pi_lock if p != current or has preemption + * disabled when p == current. + * + * The rules of PREEMPT_RT saved_state: + * + * The related locking code always holds p::pi_lock when updating + * p::saved_state, which means the code is fully serialized in both cases. + * + * The lock wait and lock wakeups happen via TASK_RTLOCK_WAIT. No other + * bits set. This allows to distinguish all wakeup scenarios. + */ +static __always_inline +bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success) +{ + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) { + WARN_ON_ONCE((state & TASK_RTLOCK_WAIT) && + state != TASK_RTLOCK_WAIT); + } + + if (READ_ONCE(p->__state) & state) { + *success = 1; + return true; + } + +#ifdef CONFIG_PREEMPT_RT + /* + * Saved state preserves the task state across blocking on + * an RT lock. If the state matches, set p::saved_state to + * TASK_RUNNING, but do not wake the task because it waits + * for a lock wakeup. Also indicate success because from + * the regular waker's point of view this has succeeded. + * + * After acquiring the lock the task will restore p::__state + * from p::saved_state which ensures that the regular + * wakeup is not lost. The restore will also set + * p::saved_state to TASK_RUNNING so any further tests will + * not result in false positives vs. @success + */ + if (p->saved_state & state) { + p->saved_state = TASK_RUNNING; + *success = 1; + } +#endif + return false; +} + +/* * Notes on Program-Order guarantees on SMP systems. * * MIGRATION @@ -3727,10 +3824,9 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * - we're serialized against set_special_state() by virtue of * it disabling IRQs (this allows not taking ->pi_lock). */ - if (!(READ_ONCE(p->__state) & state)) + if (!ttwu_state_match(p, state, &success)) goto out; - success = 1; trace_sched_waking(p); WRITE_ONCE(p->__state, TASK_RUNNING); trace_sched_wakeup(p); @@ -3745,14 +3841,11 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) */ raw_spin_lock_irqsave(&p->pi_lock, flags); smp_mb__after_spinlock(); - if (!(READ_ONCE(p->__state) & state)) + if (!ttwu_state_match(p, state, &success)) goto unlock; trace_sched_waking(p); - /* We're going to change ->state: */ - success = 1; - /* * Ensure we load p->on_rq _after_ p->state, otherwise it would * be possible to, falsely, observe p->on_rq == 0 and get stuck @@ -4149,6 +4242,9 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) p->on_cpu = 0; #endif init_task_preempt_count(p); +#ifdef CONFIG_HAVE_PREEMPT_LAZY + task_thread_info(p)->preempt_lazy_count = 0; +#endif #ifdef CONFIG_SMP plist_node_init(&p->pushable_tasks, MAX_PRIO); RB_CLEAR_NODE(&p->pushable_dl_tasks); @@ -4603,23 +4699,18 @@ static struct rq *finish_task_switch(struct task_struct *prev) * provided by mmdrop(), * - a sync_core for SYNC_CORE. */ + /* + * We use mmdrop_delayed() here so we don't have to do the + * full __mmdrop() when we are the last user. + */ if (mm) { membarrier_mm_sync_core_before_usermode(mm); - mmdrop(mm); + mmdrop_delayed(mm); } if (unlikely(prev_state == TASK_DEAD)) { if (prev->sched_class->task_dead) prev->sched_class->task_dead(prev); - /* - * Remove function-return probe instances associated with this - * task and put them back on the free list. - */ - kprobe_flush_task(prev); - - /* Task is done with its stack. */ - put_task_stack(prev); - put_task_struct_rcu_user(prev); } @@ -5877,6 +5968,24 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) #endif /* CONFIG_SCHED_CORE */ /* + * Constants for the sched_mode argument of __schedule(). + * + * The mode argument allows RT enabled kernels to differentiate a + * preemption from blocking on an 'sleeping' spin/rwlock. Note that + * SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to + * optimize the AND operation out and just check for zero. + */ +#define SM_NONE 0x0 +#define SM_PREEMPT 0x1 +#define SM_RTLOCK_WAIT 0x2 + +#ifndef CONFIG_PREEMPT_RT +# define SM_MASK_PREEMPT (~0U) +#else +# define SM_MASK_PREEMPT SM_PREEMPT +#endif + +/* * __schedule() is the main scheduler function. * * The main means of driving the scheduler and thus entering this function are: @@ -5915,7 +6024,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) * * WARNING: must be called with preemption disabled! */ -static void __sched notrace __schedule(bool preempt) +static void __sched notrace __schedule(unsigned int sched_mode) { struct task_struct *prev, *next; unsigned long *switch_count; @@ -5928,13 +6037,13 @@ static void __sched notrace __schedule(bool preempt) rq = cpu_rq(cpu); prev = rq->curr; - schedule_debug(prev, preempt); + schedule_debug(prev, !!sched_mode); if (sched_feat(HRTICK) || sched_feat(HRTICK_DL)) hrtick_clear(rq); local_irq_disable(); - rcu_note_context_switch(preempt); + rcu_note_context_switch(!!sched_mode); /* * Make sure that signal_pending_state()->signal_pending() below @@ -5968,7 +6077,7 @@ static void __sched notrace __schedule(bool preempt) * - ptrace_{,un}freeze_traced() can change ->state underneath us. */ prev_state = READ_ONCE(prev->__state); - if (!preempt && prev_state) { + if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) { if (signal_pending_state(prev_state, prev)) { WRITE_ONCE(prev->__state, TASK_RUNNING); } else { @@ -6003,6 +6112,7 @@ static void __sched notrace __schedule(bool preempt) next = pick_next_task(rq, prev, &rf); clear_tsk_need_resched(prev); + clear_tsk_need_resched_lazy(prev); clear_preempt_need_resched(); #ifdef CONFIG_SCHED_DEBUG rq->last_seen_need_resched_ns = 0; @@ -6034,7 +6144,7 @@ static void __sched notrace __schedule(bool preempt) migrate_disable_switch(rq, prev); psi_sched_switch(prev, next, !task_on_rq_queued(prev)); - trace_sched_switch(preempt, prev, next); + trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next); /* Also unlocks the rq: */ rq = context_switch(rq, prev, next, &rf); @@ -6055,7 +6165,7 @@ void __noreturn do_task_dead(void) /* Tell freezer to ignore us: */ current->flags |= PF_NOFREEZE; - __schedule(false); + __schedule(SM_NONE); BUG(); /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */ @@ -6116,7 +6226,7 @@ asmlinkage __visible void __sched schedule(void) sched_submit_work(tsk); do { preempt_disable(); - __schedule(false); + __schedule(SM_NONE); sched_preempt_enable_no_resched(); } while (need_resched()); sched_update_worker(tsk); @@ -6144,7 +6254,7 @@ void __sched schedule_idle(void) */ WARN_ON_ONCE(current->__state); do { - __schedule(false); + __schedule(SM_NONE); } while (need_resched()); } @@ -6179,6 +6289,18 @@ void __sched schedule_preempt_disabled(void) preempt_disable(); } +#ifdef CONFIG_PREEMPT_RT +void __sched notrace schedule_rtlock(void) +{ + do { + preempt_disable(); + __schedule(SM_RTLOCK_WAIT); + sched_preempt_enable_no_resched(); + } while (need_resched()); +} +NOKPROBE_SYMBOL(schedule_rtlock); +#endif + static void __sched notrace preempt_schedule_common(void) { do { @@ -6197,7 +6319,7 @@ static void __sched notrace preempt_schedule_common(void) */ preempt_disable_notrace(); preempt_latency_start(1); - __schedule(true); + __schedule(SM_PREEMPT); preempt_latency_stop(1); preempt_enable_no_resched_notrace(); @@ -6208,6 +6330,30 @@ static void __sched notrace preempt_schedule_common(void) } while (need_resched()); } +#ifdef CONFIG_PREEMPT_LAZY +/* + * If TIF_NEED_RESCHED is then we allow to be scheduled away since this is + * set by a RT task. Oterwise we try to avoid beeing scheduled out as long as + * preempt_lazy_count counter >0. + */ +static __always_inline int preemptible_lazy(void) +{ + if (test_thread_flag(TIF_NEED_RESCHED)) + return 1; + if (current_thread_info()->preempt_lazy_count) + return 0; + return 1; +} + +#else + +static inline int preemptible_lazy(void) +{ + return 1; +} + +#endif + #ifdef CONFIG_PREEMPTION /* * This is the entry point to schedule() from in-kernel preemption @@ -6221,7 +6367,8 @@ asmlinkage __visible void __sched notrace preempt_schedule(void) */ if (likely(!preemptible())) return; - + if (!preemptible_lazy()) + return; preempt_schedule_common(); } NOKPROBE_SYMBOL(preempt_schedule); @@ -6254,6 +6401,9 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) if (likely(!preemptible())) return; + if (!preemptible_lazy()) + return; + do { /* * Because the function tracer can trace preempt_count_sub() @@ -6276,7 +6426,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) * an infinite recursion. */ prev_ctx = exception_enter(); - __schedule(true); + __schedule(SM_PREEMPT); exception_exit(prev_ctx); preempt_latency_stop(1); @@ -6425,7 +6575,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void) do { preempt_disable(); local_irq_enable(); - __schedule(true); + __schedule(SM_PREEMPT); local_irq_disable(); sched_preempt_enable_no_resched(); } while (need_resched()); @@ -8375,7 +8525,9 @@ void __init init_idle(struct task_struct *idle, int cpu) /* Set the preempt count _outside_ the spinlocks! */ init_idle_preempt_count(idle, cpu); - +#ifdef CONFIG_HAVE_PREEMPT_LAZY + task_thread_info(idle)->preempt_lazy_count = 0; +#endif /* * The idle tasks have their own, simple scheduling class: */ @@ -8480,6 +8632,7 @@ void sched_setnuma(struct task_struct *p, int nid) #endif /* CONFIG_NUMA_BALANCING */ #ifdef CONFIG_HOTPLUG_CPU + /* * Ensure that the idle task is using init_mm right before its CPU goes * offline. @@ -9172,7 +9325,7 @@ void __init sched_init(void) #ifdef CONFIG_DEBUG_ATOMIC_SLEEP static inline int preempt_count_equals(int preempt_offset) { - int nested = preempt_count() + rcu_preempt_depth(); + int nested = preempt_count() + sched_rcu_preempt_depth(); return (nested == preempt_offset); } diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index e94314633b39..fd7c4f972aaf 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -800,7 +800,7 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se) * entity. */ if (dl_time_before(dl_se->deadline, rq_clock(rq))) { - printk_deferred_once("sched: DL replenish lagged too much\n"); + printk_once("sched: DL replenish lagged too much\n"); dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline; dl_se->runtime = pi_of(dl_se)->dl_runtime; } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 423ec671a306..4b08a25703a7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4205,10 +4205,7 @@ static inline void check_schedstat_required(void) trace_sched_stat_iowait_enabled() || trace_sched_stat_blocked_enabled() || trace_sched_stat_runtime_enabled()) { - printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, " - "stat_blocked and stat_runtime require the " - "kernel parameter schedstats=enable or " - "kernel.sched_schedstats=1\n"); + printk_once("Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1\n"); } #endif } @@ -4416,7 +4413,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) ideal_runtime = sched_slice(cfs_rq, curr); delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; if (delta_exec > ideal_runtime) { - resched_curr(rq_of(cfs_rq)); + resched_curr_lazy(rq_of(cfs_rq)); /* * The current task ran long enough, ensure it doesn't get * re-elected due to buddy favours. @@ -4440,7 +4437,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) return; if (delta > ideal_runtime) - resched_curr(rq_of(cfs_rq)); + resched_curr_lazy(rq_of(cfs_rq)); } static void @@ -4583,7 +4580,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) * validating it and just reschedule. */ if (queued) { - resched_curr(rq_of(cfs_rq)); + resched_curr_lazy(rq_of(cfs_rq)); return; } /* @@ -4723,7 +4720,7 @@ static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) * hierarchy can be throttled */ if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) - resched_curr(rq_of(cfs_rq)); + resched_curr_lazy(rq_of(cfs_rq)); } static __always_inline @@ -5474,7 +5471,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p) if (delta < 0) { if (task_current(rq, p)) - resched_curr(rq); + resched_curr_lazy(rq); return; } hrtick_start(rq, delta); @@ -7142,7 +7139,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ return; preempt: - resched_curr(rq); + resched_curr_lazy(rq); /* * Only set the backward buddy when the current task is still * on the rq. This can happen when a wakeup gets interleaved @@ -11041,7 +11038,7 @@ static void task_fork_fair(struct task_struct *p) * 'current' within the tree based on its new key value. */ swap(curr->vruntime, se->vruntime); - resched_curr(rq); + resched_curr_lazy(rq); } se->vruntime -= cfs_rq->min_vruntime; @@ -11068,7 +11065,7 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) */ if (task_current(rq, p)) { if (p->prio > oldprio) - resched_curr(rq); + resched_curr_lazy(rq); } else check_preempt_curr(rq, p, 0); } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 7f8dace0964c..d5cee51819bf 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -46,11 +46,19 @@ SCHED_FEAT(DOUBLE_TICK, false) */ SCHED_FEAT(NONTASK_CAPACITY, true) +#ifdef CONFIG_PREEMPT_RT +SCHED_FEAT(TTWU_QUEUE, false) +# ifdef CONFIG_PREEMPT_LAZY +SCHED_FEAT(PREEMPT_LAZY, true) +# endif +#else + /* * Queue remote wakeups on the target CPU and process them * using the scheduler IPI. Reduces rq->lock contention/bounces. */ SCHED_FEAT(TTWU_QUEUE, true) +#endif /* * When doing wakeups, attempt to limit superfluous scans of the LLC domain. diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 1652f2bb54b7..ab54b2012469 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -710,10 +710,10 @@ static void psi_group_change(struct psi_group *group, int cpu, if (groupc->tasks[t]) { groupc->tasks[t]--; } else if (!psi_bug) { - printk_deferred(KERN_ERR "psi: task underflow! cpu=%d t=%d tasks=[%u %u %u %u] clear=%x set=%x\n", - cpu, t, groupc->tasks[0], - groupc->tasks[1], groupc->tasks[2], - groupc->tasks[3], clear, set); + pr_err("psi: task underflow! cpu=%d t=%d tasks=[%u %u %u %u] clear=%x set=%x\n", + cpu, t, groupc->tasks[0], + groupc->tasks[1], groupc->tasks[2], + groupc->tasks[3], clear, set); psi_bug = 1; } } @@ -779,9 +779,9 @@ static void psi_flags_change(struct task_struct *task, int clear, int set) if (((task->psi_flags & set) || (task->psi_flags & clear) != clear) && !psi_bug) { - printk_deferred(KERN_ERR "psi: inconsistent task state! task=%d:%s cpu=%d psi_flags=%x clear=%x set=%x\n", - task->pid, task->comm, task_cpu(task), - task->psi_flags, clear, set); + pr_err("psi: inconsistent task state! task=%d:%s cpu=%d psi_flags=%x clear=%x set=%x\n", + task->pid, task->comm, task_cpu(task), + task->psi_flags, clear, set); psi_bug = 1; } diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 3daf42a0f462..151e384d53a9 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -971,7 +971,7 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) */ if (likely(rt_b->rt_runtime)) { rt_rq->rt_throttled = 1; - printk_deferred_once("sched: RT throttling activated\n"); + printk_once("sched: RT throttling activated\n"); } else { /* * In case we did anyway, make it go away, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d53d19770866..561d12682a2e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2308,6 +2308,15 @@ extern void reweight_task(struct task_struct *p, int prio); extern void resched_curr(struct rq *rq); extern void resched_cpu(int cpu); +#ifdef CONFIG_PREEMPT_LAZY +extern void resched_curr_lazy(struct rq *rq); +#else +static inline void resched_curr_lazy(struct rq *rq) +{ + resched_curr(rq); +} +#endif + extern struct rt_bandwidth def_rt_bandwidth; extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime); diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index e1c655f928c7..f230b1ac7f91 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -64,6 +64,7 @@ void swake_up_all(struct swait_queue_head *q) struct swait_queue *curr; LIST_HEAD(tmp); + WARN_ON(irqs_disabled()); raw_spin_lock_irq(&q->lock); list_splice_init(&q->task_list, &tmp); while (!list_empty(&tmp)) { diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 4e8698e62f07..27cd0052a222 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -526,7 +526,8 @@ static int init_rootdomain(struct root_domain *rd) #ifdef HAVE_RT_PUSH_IPI rd->rto_cpu = -1; raw_spin_lock_init(&rd->rto_lock); - init_irq_work(&rd->rto_push_work, rto_push_irq_work_func); +// init_irq_work(&rd->rto_push_work, rto_push_irq_work_func); + rd->rto_push_work = IRQ_WORK_INIT_HARD(rto_push_irq_work_func); #endif rd->visit_gen = 0; diff --git a/kernel/signal.c b/kernel/signal.c index 59af8e2f4008..e66aec396be1 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1316,6 +1316,34 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t) struct k_sigaction *action; int sig = info->si_signo; + /* + * On some archs, PREEMPT_RT has to delay sending a signal from a trap + * since it can not enable preemption, and the signal code's spin_locks + * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will + * send the signal on exit of the trap. + */ +#ifdef ARCH_RT_DELAYS_SIGNAL_SEND + if (in_atomic()) { + struct task_struct *t = current; + + if (WARN_ON_ONCE(t->forced_info.si_signo)) + return 0; + + if (is_si_special(info)) { + WARN_ON_ONCE(info != SEND_SIG_PRIV); + t->forced_info.si_signo = info->si_signo; + t->forced_info.si_errno = 0; + t->forced_info.si_code = SI_KERNEL; + t->forced_info.si_pid = 0; + t->forced_info.si_uid = 0; + } else { + t->forced_info = *info; + } + + set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); + return 0; + } +#endif spin_lock_irqsave(&t->sighand->siglock, flags); action = &t->sighand->action[sig-1]; ignored = action->sa.sa_handler == SIG_IGN; @@ -2205,16 +2233,8 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t if (gstop_done && ptrace_reparented(current)) do_notify_parent_cldstop(current, false, why); - /* - * Don't want to allow preemption here, because - * sys_ptrace() needs this task to be inactive. - * - * XXX: implement read_unlock_no_resched(). - */ - preempt_disable(); read_unlock(&tasklist_lock); cgroup_enter_frozen(); - preempt_enable_no_resched(); freezable_schedule(); cgroup_leave_frozen(true); } else { diff --git a/kernel/smp.c b/kernel/smp.c index 52bf159ec400..3ce4e9656019 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -690,10 +690,21 @@ void flush_smp_call_function_from_idle(void) cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU, smp_processor_id(), CFD_SEQ_IDLE); + local_irq_save(flags); flush_smp_call_function_queue(true); - if (local_softirq_pending()) - do_softirq(); + + if (local_softirq_pending()) { + + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { + do_softirq(); + } else { + struct task_struct *ksoftirqd = this_cpu_ksoftirqd(); + + if (ksoftirqd && task_is_running(ksoftirqd)) + wake_up_process(ksoftirqd); + } + } local_irq_restore(flags); } diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 003ccf338d20..00fc43605c6b 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -203,8 +203,7 @@ static int clockevents_increase_min_delta(struct clock_event_device *dev) { /* Nothing to do if we already reached the limit */ if (dev->min_delta_ns >= MIN_DELTA_LIMIT) { - printk_deferred(KERN_WARNING - "CE: Reprogramming failure. Giving up\n"); + pr_warn("CE: Reprogramming failure. Giving up\n"); dev->next_event = KTIME_MAX; return -ETIME; } @@ -217,10 +216,8 @@ static int clockevents_increase_min_delta(struct clock_event_device *dev) if (dev->min_delta_ns > MIN_DELTA_LIMIT) dev->min_delta_ns = MIN_DELTA_LIMIT; - printk_deferred(KERN_WARNING - "CE: %s increased min_delta_ns to %llu nsec\n", - dev->name ? dev->name : "?", - (unsigned long long) dev->min_delta_ns); + pr_warn("CE: %s increased min_delta_ns to %llu nsec\n", + dev->name ? dev->name : "?", (unsigned long long) dev->min_delta_ns); return 0; } diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 5af758473488..bdcbf3036a40 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1468,6 +1468,7 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, base += hrtimer_clockid_to_base(clock_id); timer->is_soft = softtimer; timer->is_hard = !!(mode & HRTIMER_MODE_HARD); + timer->is_chill = !!(mode & HRTIMER_MODE_CHILL); timer->base = &cpu_base->clock_base[base]; timerqueue_init(&timer->node); } @@ -1834,7 +1835,7 @@ static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer) t->task = NULL; if (task) - wake_up_process(task); + wake_up_state(task, timer->is_chill ? TASK_RTLOCK_WAIT : TASK_NORMAL); return HRTIMER_NORESTART; } @@ -2052,6 +2053,34 @@ SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp, } #endif +#ifdef CONFIG_PREEMPT_RT +/* + * Sleep for 1 ms in hope whoever holds what we want will let it go. + */ +void cpu_chill(void) +{ + unsigned int freeze_flag = current->flags & PF_NOFREEZE; + ktime_t chill_time; + + local_irq_disable(); + current_save_and_set_rtlock_wait_state(); + local_irq_enable(); + + chill_time = ktime_set(0, NSEC_PER_MSEC); + + current->flags |= PF_NOFREEZE; + schedule_hrtimeout(&chill_time, + HRTIMER_MODE_REL_HARD| HRTIMER_MODE_CHILL); + if (!freeze_flag) + current->flags &= ~PF_NOFREEZE; + + local_irq_disable(); + current_restore_rtlock_saved_state(); + local_irq_enable(); +} +EXPORT_SYMBOL(cpu_chill); +#endif + /* * Functions related to boot-time initialization: */ diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 406dccb79c2b..829d7797811f 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -939,9 +939,7 @@ static long hardpps_update_freq(struct pps_normtime freq_norm) time_status |= STA_PPSERROR; pps_errcnt++; pps_dec_freq_interval(); - printk_deferred(KERN_ERR - "hardpps: PPSERROR: interval too long - %lld s\n", - freq_norm.sec); + pr_err("hardpps: PPSERROR: interval too long - %lld s\n", freq_norm.sec); return 0; } @@ -954,8 +952,7 @@ static long hardpps_update_freq(struct pps_normtime freq_norm) delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT); pps_freq = ftemp; if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) { - printk_deferred(KERN_WARNING - "hardpps: PPSWANDER: change=%ld\n", delta); + pr_warn("hardpps: PPSWANDER: change=%ld\n", delta); time_status |= STA_PPSWANDER; pps_stbcnt++; pps_dec_freq_interval(); @@ -999,9 +996,8 @@ static void hardpps_update_phase(long error) * the time offset is updated. */ if (jitter > (pps_jitter << PPS_POPCORN)) { - printk_deferred(KERN_WARNING - "hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", - jitter, (pps_jitter << PPS_POPCORN)); + pr_warn("hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", + jitter, (pps_jitter << PPS_POPCORN)); time_status |= STA_PPSJITTER; pps_jitcnt++; } else if (time_status & STA_PPSTIME) { @@ -1058,7 +1054,7 @@ void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_t time_status |= STA_PPSJITTER; /* restart the frequency calibration interval */ pps_fbase = *raw_ts; - printk_deferred(KERN_ERR "hardpps: PPSJITTER: bad pulse\n"); + pr_err("hardpps: PPSJITTER: bad pulse\n"); return; } diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 8a364aa9881a..f30bcddbec4f 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -203,22 +203,23 @@ static void timekeeping_check_update(struct timekeeper *tk, u64 offset) const char *name = tk->tkr_mono.clock->name; if (offset > max_cycles) { - printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n", - offset, name, max_cycles); - printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n"); + printk("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n", + offset, name, max_cycles); + printk(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n"); } else { if (offset > (max_cycles >> 1)) { - printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n", - offset, name, max_cycles >> 1); - printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n"); + printk("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n", + offset, name, max_cycles >> 1); + printk(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n"); } } if (tk->underflow_seen) { if (jiffies - tk->last_warning > WARNING_FREQ) { - printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name); - printk_deferred(" Please report this, consider using a different clocksource, if possible.\n"); - printk_deferred(" Your kernel is probably still fine.\n"); + printk("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", + name); + printk(" Please report this, consider using a different clocksource, if possible.\n"); + printk(" Your kernel is probably still fine.\n"); tk->last_warning = jiffies; } tk->underflow_seen = 0; @@ -226,9 +227,10 @@ static void timekeeping_check_update(struct timekeeper *tk, u64 offset) if (tk->overflow_seen) { if (jiffies - tk->last_warning > WARNING_FREQ) { - printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name); - printk_deferred(" Please report this, consider using a different clocksource, if possible.\n"); - printk_deferred(" Your kernel is probably still fine.\n"); + printk("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", + name); + printk(" Please report this, consider using a different clocksource, if possible.\n"); + printk(" Your kernel is probably still fine.\n"); tk->last_warning = jiffies; } tk->overflow_seen = 0; @@ -1669,9 +1671,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, const struct timespec64 *delta) { if (!timespec64_valid_strict(delta)) { - printk_deferred(KERN_WARNING - "__timekeeping_inject_sleeptime: Invalid " - "sleep delta value!\n"); + pr_warn("%s: Invalid sleep delta value!\n", __func__); return; } tk_xtime_add(tk, delta); diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c index b73e8850e58d..149cc4b08d8e 100644 --- a/kernel/time/timekeeping_debug.c +++ b/kernel/time/timekeeping_debug.c @@ -49,7 +49,7 @@ void tk_debug_account_sleep_time(const struct timespec64 *t) int bin = min(fls(t->tv_sec), NUM_BINS-1); sleep_time_bin[bin]++; - pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n", + pm_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n", (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC); } diff --git a/kernel/time/timer.c b/kernel/time/timer.c index e3d2c23c413d..fb235b3e91b3 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1744,6 +1744,8 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h) { struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); + irq_work_tick_soft(); + __run_timers(base); if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1b5946a3a823..633c454f3abd 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2603,6 +2603,15 @@ enum print_line_t trace_handle_return(struct trace_seq *s) } EXPORT_SYMBOL_GPL(trace_handle_return); +static unsigned short migration_disable_value(void) +{ +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT) + return current->migration_disabled; +#else + return 0; +#endif +} + unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status) { unsigned int trace_flags = irqs_status; @@ -2621,7 +2630,16 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status) trace_flags |= TRACE_FLAG_NEED_RESCHED; if (test_preempt_need_resched()) trace_flags |= TRACE_FLAG_PREEMPT_RESCHED; - return (trace_flags << 16) | (pc & 0xff); + +#ifdef CONFIG_PREEMPT_LAZY + if (need_resched_lazy()) + trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY; +#endif + + return (pc & 0xff) | + (migration_disable_value() & 0xff) << 8 | + (preempt_lazy_count() & 0xff) << 16 | + (trace_flags << 24); } struct ring_buffer_event * @@ -4184,14 +4202,17 @@ unsigned long trace_total_entries(struct trace_array *tr) static void print_lat_help_header(struct seq_file *m) { - seq_puts(m, "# _------=> CPU# \n" - "# / _-----=> irqs-off \n" - "# | / _----=> need-resched \n" - "# || / _---=> hardirq/softirq \n" - "# ||| / _--=> preempt-depth \n" - "# |||| / delay \n" - "# cmd pid ||||| time | caller \n" - "# \\ / ||||| \\ | / \n"); + seq_puts(m, "# _--------=> CPU# \n" + "# / _-------=> irqs-off \n" + "# | / _------=> need-resched \n" + "# || / _-----=> need-resched-lazy\n" + "# ||| / _----=> hardirq/softirq \n" + "# |||| / _---=> preempt-depth \n" + "# ||||| / _--=> preempt-lazy-depth\n" + "# |||||| / _-=> migrate-disable \n" + "# ||||||| / delay \n" + "# cmd pid |||||||| time | caller \n" + "# \\ / |||||||| \\ | / \n"); } static void print_event_info(struct array_buffer *buf, struct seq_file *m) @@ -4225,13 +4246,16 @@ static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file print_event_info(buf, m); - seq_printf(m, "# %.*s _-----=> irqs-off\n", prec, space); - seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space); - seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space); - seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space); - seq_printf(m, "# %.*s||| / delay\n", prec, space); - seq_printf(m, "# TASK-PID %.*s CPU# |||| TIMESTAMP FUNCTION\n", prec, " TGID "); - seq_printf(m, "# | | %.*s | |||| | |\n", prec, " | "); + seq_printf(m, "# %.*s _-------=> irqs-off\n", prec, space); + seq_printf(m, "# %.*s / _------=> need-resched\n", prec, space); + seq_printf(m, "# %.*s| / _-----=> need-resched-lazy\n", prec, space); + seq_printf(m, "# %.*s|| / _----=> hardirq/softirq\n", prec, space); + seq_printf(m, "# %.*s||| / _---=> preempt-depth\n", prec, space); + seq_printf(m, "# %.*s|||| / _--=> preempt-lazy-depth\n", prec, space); + seq_printf(m, "# %.*s||||| / _-=> migrate-disable\n", prec, space); + seq_printf(m, "# %.*s|||||| / delay\n", prec, space); + seq_printf(m, "# TASK-PID %.*s CPU# ||||||| TIMESTAMP FUNCTION\n", prec, " TGID "); + seq_printf(m, "# | | %.*s | ||||||| | |\n", prec, " | "); } void @@ -9813,7 +9837,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) tracing_off(); local_irq_save(flags); - printk_nmi_direct_enter(); /* Simulate the iterator */ trace_init_global_iter(&iter); @@ -9895,7 +9918,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); } atomic_dec(&dump_running); - printk_nmi_direct_exit(); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(ftrace_dump); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 478f328c30d1..2697dce52df7 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -183,6 +183,8 @@ static int trace_define_common_fields(void) __common_field(unsigned char, flags); __common_field(unsigned char, preempt_count); __common_field(int, pid); + __common_field(unsigned char, migrate_disable); + __common_field(unsigned char, preempt_lazy_count); return ret; } diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index a0bf446bb034..dd2bdd751aed 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -451,6 +451,7 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry) { char hardsoft_irq; char need_resched; + char need_resched_lazy; char irqs_off; int hardirq; int softirq; @@ -481,6 +482,9 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry) break; } + need_resched_lazy = + (entry->flags & TRACE_FLAG_NEED_RESCHED_LAZY) ? 'L' : '.'; + hardsoft_irq = (nmi && hardirq) ? 'Z' : nmi ? 'z' : @@ -489,14 +493,25 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry) softirq ? 's' : '.' ; - trace_seq_printf(s, "%c%c%c", - irqs_off, need_resched, hardsoft_irq); + trace_seq_printf(s, "%c%c%c%c", + irqs_off, need_resched, need_resched_lazy, + hardsoft_irq); if (entry->preempt_count) trace_seq_printf(s, "%x", entry->preempt_count); else trace_seq_putc(s, '.'); + if (entry->preempt_lazy_count) + trace_seq_printf(s, "%x", entry->preempt_lazy_count); + else + trace_seq_putc(s, '.'); + + if (entry->migrate_disable) + trace_seq_printf(s, "%x", entry->migrate_disable); + else + trace_seq_putc(s, '.'); + return !trace_seq_has_overflowed(s); } diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ffd22e499997..8baff0ab0331 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1234,7 +1234,7 @@ config PROVE_LOCKING depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select LOCKDEP select DEBUG_SPINLOCK - select DEBUG_MUTEXES + select DEBUG_MUTEXES if !PREEMPT_RT select DEBUG_RT_MUTEXES if RT_MUTEXES select DEBUG_RWSEMS select DEBUG_WW_MUTEX_SLOWPATH @@ -1298,7 +1298,7 @@ config LOCK_STAT depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select LOCKDEP select DEBUG_SPINLOCK - select DEBUG_MUTEXES + select DEBUG_MUTEXES if !PREEMPT_RT select DEBUG_RT_MUTEXES if RT_MUTEXES select DEBUG_LOCK_ALLOC default n @@ -1334,7 +1334,7 @@ config DEBUG_SPINLOCK config DEBUG_MUTEXES bool "Mutex debugging: basic checks" - depends on DEBUG_KERNEL + depends on DEBUG_KERNEL && !PREEMPT_RT help This feature allows mutex semantics violations to be detected and reported. @@ -1344,7 +1344,8 @@ config DEBUG_WW_MUTEX_SLOWPATH depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select DEBUG_LOCK_ALLOC select DEBUG_SPINLOCK - select DEBUG_MUTEXES + select DEBUG_MUTEXES if !PREEMPT_RT + select DEBUG_RT_MUTEXES if PREEMPT_RT help This feature enables slowpath testing for w/w mutex users by injecting additional -EDEADLK wound/backoff cases. Together with @@ -1367,7 +1368,7 @@ config DEBUG_LOCK_ALLOC bool "Lock debugging: detect incorrect freeing of live locks" depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select DEBUG_SPINLOCK - select DEBUG_MUTEXES + select DEBUG_MUTEXES if !PREEMPT_RT select DEBUG_RT_MUTEXES if RT_MUTEXES select LOCKDEP help diff --git a/lib/bug.c b/lib/bug.c index 45a0584f6541..03a87df69ed2 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -206,6 +206,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) else pr_crit("Kernel BUG at %pB [verbose debug info unavailable]\n", (void *)bugaddr); + pr_flush(1000, true); return BUG_TRAP_TYPE_BUG; } diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 9e14ae02306b..083882a3cf2f 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -557,7 +557,10 @@ __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack struct debug_obj *obj; unsigned long flags; - fill_pool(); +#ifdef CONFIG_PREEMPT_RT + if (preempt_count() == 0 && !irqs_disabled()) +#endif + fill_pool(); db = get_bucket((unsigned long) addr); diff --git a/lib/dump_stack.c b/lib/dump_stack.c index cd3387bb34e5..7af32829b062 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -101,9 +101,9 @@ asmlinkage __visible void dump_stack_lvl(const char *log_lvl) * Permit this cpu to perform nested stack dumps while serialising * against other CPUs */ - printk_cpu_lock_irqsave(flags); + raw_printk_cpu_lock_irqsave(flags); __dump_stack(log_lvl); - printk_cpu_unlock_irqrestore(flags); + raw_printk_cpu_unlock_irqrestore(flags); } EXPORT_SYMBOL(dump_stack_lvl); diff --git a/lib/irq_poll.c b/lib/irq_poll.c index 2f17b488d58e..7557bf7ecf1f 100644 --- a/lib/irq_poll.c +++ b/lib/irq_poll.c @@ -37,6 +37,7 @@ void irq_poll_sched(struct irq_poll *iop) list_add_tail(&iop->list, this_cpu_ptr(&blk_cpu_iopoll)); raise_softirq_irqoff(IRQ_POLL_SOFTIRQ); local_irq_restore(flags); + preempt_check_resched_rt(); } EXPORT_SYMBOL(irq_poll_sched); @@ -72,6 +73,7 @@ void irq_poll_complete(struct irq_poll *iop) local_irq_save(flags); __irq_poll_complete(iop); local_irq_restore(flags); + preempt_check_resched_rt(); } EXPORT_SYMBOL(irq_poll_complete); @@ -96,6 +98,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h) } local_irq_enable(); + preempt_check_resched_rt(); /* Even though interrupts have been re-enabled, this * access is safe because interrupts can only add new @@ -133,6 +136,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h) __raise_softirq_irqoff(IRQ_POLL_SOFTIRQ); local_irq_enable(); + preempt_check_resched_rt(); } /** @@ -196,6 +200,7 @@ static int irq_poll_cpu_dead(unsigned int cpu) this_cpu_ptr(&blk_cpu_iopoll)); __raise_softirq_irqoff(IRQ_POLL_SOFTIRQ); local_irq_enable(); + preempt_check_resched_rt(); return 0; } diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 161108e5d2fe..1266ea3726d7 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -26,6 +26,12 @@ #include <linux/rtmutex.h> #include <linux/local_lock.h> +#ifdef CONFIG_PREEMPT_RT +# define NON_RT(...) +#else +# define NON_RT(...) __VA_ARGS__ +#endif + /* * Change this to 1 if you want to see the failure printouts: */ @@ -139,7 +145,7 @@ static DEFINE_RT_MUTEX(rtmutex_Z2); #endif -static local_lock_t local_A = INIT_LOCAL_LOCK(local_A); +static DEFINE_PER_CPU(local_lock_t, local_A); /* * non-inlined runtime initializers, to let separate locks share @@ -712,12 +718,18 @@ GENERATE_TESTCASE(ABCDBCDA_rtmutex); #undef E +#ifdef CONFIG_PREEMPT_RT +# define RT_PREPARE_DBL_UNLOCK() { migrate_disable(); rcu_read_lock(); } +#else +# define RT_PREPARE_DBL_UNLOCK() +#endif /* * Double unlock: */ #define E() \ \ LOCK(A); \ + RT_PREPARE_DBL_UNLOCK(); \ UNLOCK(A); \ UNLOCK(A); /* fail */ @@ -802,6 +814,7 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_rlock) #include "locking-selftest-wlock-hardirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-spin-softirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_spin) @@ -810,10 +823,12 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_rlock) #include "locking-selftest-wlock-softirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_wlock) +#endif #undef E1 #undef E2 +#ifndef CONFIG_PREEMPT_RT /* * Enabling hardirqs with a softirq-safe lock held: */ @@ -846,6 +861,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock) #undef E1 #undef E2 +#endif + /* * Enabling irqs with an irq-safe lock held: */ @@ -875,6 +892,7 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_rlock) #include "locking-selftest-wlock-hardirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-spin-softirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_spin) @@ -883,6 +901,7 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_rlock) #include "locking-selftest-wlock-softirq.h" GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock) +#endif #undef E1 #undef E2 @@ -921,6 +940,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_rlock) #include "locking-selftest-wlock-hardirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-spin-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_spin) @@ -929,6 +949,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_rlock) #include "locking-selftest-wlock-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock) +#endif #undef E1 #undef E2 @@ -969,6 +990,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_rlock) #include "locking-selftest-wlock-hardirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-spin-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_spin) @@ -977,6 +999,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_rlock) #include "locking-selftest-wlock-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_wlock) +#endif #undef E1 #undef E2 @@ -1031,6 +1054,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_hard_rlock) #include "locking-selftest-wlock-hardirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-spin-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_spin) @@ -1039,6 +1063,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_rlock) #include "locking-selftest-wlock-softirq.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_wlock) +#endif #undef E1 #undef E2 @@ -1206,12 +1231,14 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_hard_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-softirq.h" #include "locking-selftest-rlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft_wlock) +#endif #undef E1 #undef E2 @@ -1252,12 +1279,14 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_hard_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-softirq.h" #include "locking-selftest-rlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft_wlock) +#endif #undef E1 #undef E2 @@ -1306,12 +1335,14 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_hard_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_hard_wlock) +#ifndef CONFIG_PREEMPT_RT #include "locking-selftest-softirq.h" #include "locking-selftest-rlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock) +#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC # define I_SPINLOCK(x) lockdep_reset_lock(&lock_##x.dep_map) @@ -1320,7 +1351,7 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock) # define I_MUTEX(x) lockdep_reset_lock(&mutex_##x.dep_map) # define I_RWSEM(x) lockdep_reset_lock(&rwsem_##x.dep_map) # define I_WW(x) lockdep_reset_lock(&x.dep_map) -# define I_LOCAL_LOCK(x) lockdep_reset_lock(&local_##x.dep_map) +# define I_LOCAL_LOCK(x) lockdep_reset_lock(this_cpu_ptr(&local_##x.dep_map)) #ifdef CONFIG_RT_MUTEXES # define I_RTMUTEX(x) lockdep_reset_lock(&rtmutex_##x.dep_map) #endif @@ -1380,7 +1411,7 @@ static void reset_locks(void) init_shared_classes(); raw_spin_lock_init(&raw_lock_A); raw_spin_lock_init(&raw_lock_B); - local_lock_init(&local_A); + local_lock_init(this_cpu_ptr(&local_A)); ww_mutex_init(&o, &ww_lockdep); ww_mutex_init(&o2, &ww_lockdep); ww_mutex_init(&o3, &ww_lockdep); memset(&t, 0, sizeof(t)); memset(&t2, 0, sizeof(t2)); @@ -1398,7 +1429,13 @@ static int unexpected_testcase_failures; static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask) { - unsigned long saved_preempt_count = preempt_count(); + int saved_preempt_count = preempt_count(); +#ifdef CONFIG_PREEMPT_RT +#ifdef CONFIG_SMP + int saved_mgd_count = current->migration_disabled; +#endif + int saved_rcu_count = current->rcu_read_lock_nesting; +#endif WARN_ON(irqs_disabled()); @@ -1432,6 +1469,18 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask) * count, so restore it: */ preempt_count_set(saved_preempt_count); + +#ifdef CONFIG_PREEMPT_RT +#ifdef CONFIG_SMP + while (current->migration_disabled > saved_mgd_count) + migrate_enable(); +#endif + + while (current->rcu_read_lock_nesting > saved_rcu_count) + rcu_read_unlock(); + WARN_ON_ONCE(current->rcu_read_lock_nesting < saved_rcu_count); +#endif + #ifdef CONFIG_TRACE_IRQFLAGS if (softirq_count()) current->softirqs_enabled = 0; @@ -1499,7 +1548,7 @@ static inline void print_testname(const char *testname) #define DO_TESTCASE_2x2RW(desc, name, nr) \ DO_TESTCASE_2RW("hard-"desc, name##_hard, nr) \ - DO_TESTCASE_2RW("soft-"desc, name##_soft, nr) \ + NON_RT(DO_TESTCASE_2RW("soft-"desc, name##_soft, nr)) \ #define DO_TESTCASE_6x2x2RW(desc, name) \ DO_TESTCASE_2x2RW(desc, name, 123); \ @@ -1547,19 +1596,19 @@ static inline void print_testname(const char *testname) #define DO_TESTCASE_2I(desc, name, nr) \ DO_TESTCASE_1("hard-"desc, name##_hard, nr); \ - DO_TESTCASE_1("soft-"desc, name##_soft, nr); + NON_RT(DO_TESTCASE_1("soft-"desc, name##_soft, nr)); #define DO_TESTCASE_2IB(desc, name, nr) \ DO_TESTCASE_1B("hard-"desc, name##_hard, nr); \ - DO_TESTCASE_1B("soft-"desc, name##_soft, nr); + NON_RT(DO_TESTCASE_1B("soft-"desc, name##_soft, nr)); #define DO_TESTCASE_6I(desc, name, nr) \ DO_TESTCASE_3("hard-"desc, name##_hard, nr); \ - DO_TESTCASE_3("soft-"desc, name##_soft, nr); + NON_RT(DO_TESTCASE_3("soft-"desc, name##_soft, nr)); #define DO_TESTCASE_6IRW(desc, name, nr) \ DO_TESTCASE_3RW("hard-"desc, name##_hard, nr); \ - DO_TESTCASE_3RW("soft-"desc, name##_soft, nr); + NON_RT(DO_TESTCASE_3RW("soft-"desc, name##_soft, nr)); #define DO_TESTCASE_2x3(desc, name) \ DO_TESTCASE_3(desc, name, 12); \ @@ -1651,6 +1700,20 @@ static void ww_test_fail_acquire(void) #endif } +#ifdef CONFIG_PREEMPT_RT +#define ww_mutex_base_lock(b) rt_mutex_lock(b) +#define ww_mutex_base_lock_nest_lock(b, b2) rt_mutex_lock_nest_lock(b, b2) +#define ww_mutex_base_lock_interruptible(b) rt_mutex_lock_interruptible(b) +#define ww_mutex_base_lock_killable(b) rt_mutex_lock_killable(b) +#define ww_mutex_base_unlock(b) rt_mutex_unlock(b) +#else +#define ww_mutex_base_lock(b) mutex_lock(b) +#define ww_mutex_base_lock_nest_lock(b, b2) mutex_lock_nest_lock(b, b2) +#define ww_mutex_base_lock_interruptible(b) mutex_lock_interruptible(b) +#define ww_mutex_base_lock_killable(b) mutex_lock_killable(b) +#define ww_mutex_base_unlock(b) mutex_unlock(b) +#endif + static void ww_test_normal(void) { int ret; @@ -1665,50 +1728,50 @@ static void ww_test_normal(void) /* mutex_lock (and indirectly, mutex_lock_nested) */ o.ctx = (void *)~0UL; - mutex_lock(&o.base); - mutex_unlock(&o.base); + ww_mutex_base_lock(&o.base); + ww_mutex_base_unlock(&o.base); WARN_ON(o.ctx != (void *)~0UL); /* mutex_lock_interruptible (and *_nested) */ o.ctx = (void *)~0UL; - ret = mutex_lock_interruptible(&o.base); + ret = ww_mutex_base_lock_interruptible(&o.base); if (!ret) - mutex_unlock(&o.base); + ww_mutex_base_unlock(&o.base); else WARN_ON(1); WARN_ON(o.ctx != (void *)~0UL); /* mutex_lock_killable (and *_nested) */ o.ctx = (void *)~0UL; - ret = mutex_lock_killable(&o.base); + ret = ww_mutex_base_lock_killable(&o.base); if (!ret) - mutex_unlock(&o.base); + ww_mutex_base_unlock(&o.base); else WARN_ON(1); WARN_ON(o.ctx != (void *)~0UL); /* trylock, succeeding */ o.ctx = (void *)~0UL; - ret = mutex_trylock(&o.base); + ret = ww_mutex_base_trylock(&o.base); WARN_ON(!ret); if (ret) - mutex_unlock(&o.base); + ww_mutex_base_unlock(&o.base); else WARN_ON(1); WARN_ON(o.ctx != (void *)~0UL); /* trylock, failing */ o.ctx = (void *)~0UL; - mutex_lock(&o.base); - ret = mutex_trylock(&o.base); + ww_mutex_base_lock(&o.base); + ret = ww_mutex_base_trylock(&o.base); WARN_ON(ret); - mutex_unlock(&o.base); + ww_mutex_base_unlock(&o.base); WARN_ON(o.ctx != (void *)~0UL); /* nest_lock */ o.ctx = (void *)~0UL; - mutex_lock_nest_lock(&o.base, &t); - mutex_unlock(&o.base); + ww_mutex_base_lock_nest_lock(&o.base, &t); + ww_mutex_base_unlock(&o.base); WARN_ON(o.ctx != (void *)~0UL); } @@ -1721,7 +1784,7 @@ static void ww_test_two_contexts(void) static void ww_test_diff_class(void) { WWAI(&t); -#ifdef CONFIG_DEBUG_MUTEXES +#ifdef DEBUG_WW_MUTEXES t.ww_class = NULL; #endif WWL(&o, &t); @@ -1785,7 +1848,7 @@ static void ww_test_edeadlk_normal(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); o2.ctx = &t2; mutex_release(&o2.base.dep_map, _THIS_IP_); @@ -1801,7 +1864,7 @@ static void ww_test_edeadlk_normal(void) o2.ctx = NULL; mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); - mutex_unlock(&o2.base); + ww_mutex_base_unlock(&o2.base); WWU(&o); WWL(&o2, &t); @@ -1811,7 +1874,7 @@ static void ww_test_edeadlk_normal_slow(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -1827,7 +1890,7 @@ static void ww_test_edeadlk_normal_slow(void) o2.ctx = NULL; mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); - mutex_unlock(&o2.base); + ww_mutex_base_unlock(&o2.base); WWU(&o); ww_mutex_lock_slow(&o2, &t); @@ -1837,7 +1900,7 @@ static void ww_test_edeadlk_no_unlock(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); o2.ctx = &t2; mutex_release(&o2.base.dep_map, _THIS_IP_); @@ -1853,7 +1916,7 @@ static void ww_test_edeadlk_no_unlock(void) o2.ctx = NULL; mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); - mutex_unlock(&o2.base); + ww_mutex_base_unlock(&o2.base); WWL(&o2, &t); } @@ -1862,7 +1925,7 @@ static void ww_test_edeadlk_no_unlock_slow(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -1878,7 +1941,7 @@ static void ww_test_edeadlk_no_unlock_slow(void) o2.ctx = NULL; mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); - mutex_unlock(&o2.base); + ww_mutex_base_unlock(&o2.base); ww_mutex_lock_slow(&o2, &t); } @@ -1887,7 +1950,7 @@ static void ww_test_edeadlk_acquire_more(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -1908,7 +1971,7 @@ static void ww_test_edeadlk_acquire_more_slow(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -1929,11 +1992,11 @@ static void ww_test_edeadlk_acquire_more_edeadlk(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; - mutex_lock(&o3.base); + ww_mutex_base_lock(&o3.base); mutex_release(&o3.base.dep_map, _THIS_IP_); o3.ctx = &t2; @@ -1955,11 +2018,11 @@ static void ww_test_edeadlk_acquire_more_edeadlk_slow(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; - mutex_lock(&o3.base); + ww_mutex_base_lock(&o3.base); mutex_release(&o3.base.dep_map, _THIS_IP_); o3.ctx = &t2; @@ -1980,7 +2043,7 @@ static void ww_test_edeadlk_acquire_wrong(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -2005,7 +2068,7 @@ static void ww_test_edeadlk_acquire_wrong_slow(void) { int ret; - mutex_lock(&o2.base); + ww_mutex_base_lock(&o2.base); mutex_release(&o2.base.dep_map, _THIS_IP_); o2.ctx = &t2; @@ -2646,8 +2709,8 @@ static void wait_context_tests(void) static void local_lock_2(void) { - local_lock_acquire(&local_A); /* IRQ-ON */ - local_lock_release(&local_A); + local_lock(&local_A); /* IRQ-ON */ + local_unlock(&local_A); HARDIRQ_ENTER(); spin_lock(&lock_A); /* IN-IRQ */ @@ -2656,18 +2719,18 @@ static void local_lock_2(void) HARDIRQ_DISABLE(); spin_lock(&lock_A); - local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle, false */ - local_lock_release(&local_A); + local_lock(&local_A); /* IN-IRQ <-> IRQ-ON cycle, false */ + local_unlock(&local_A); spin_unlock(&lock_A); HARDIRQ_ENABLE(); } static void local_lock_3A(void) { - local_lock_acquire(&local_A); /* IRQ-ON */ + local_lock(&local_A); /* IRQ-ON */ spin_lock(&lock_B); /* IRQ-ON */ spin_unlock(&lock_B); - local_lock_release(&local_A); + local_unlock(&local_A); HARDIRQ_ENTER(); spin_lock(&lock_A); /* IN-IRQ */ @@ -2676,18 +2739,18 @@ static void local_lock_3A(void) HARDIRQ_DISABLE(); spin_lock(&lock_A); - local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */ - local_lock_release(&local_A); + local_lock(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */ + local_unlock(&local_A); spin_unlock(&lock_A); HARDIRQ_ENABLE(); } static void local_lock_3B(void) { - local_lock_acquire(&local_A); /* IRQ-ON */ + local_lock(&local_A); /* IRQ-ON */ spin_lock(&lock_B); /* IRQ-ON */ spin_unlock(&lock_B); - local_lock_release(&local_A); + local_unlock(&local_A); HARDIRQ_ENTER(); spin_lock(&lock_A); /* IN-IRQ */ @@ -2696,8 +2759,8 @@ static void local_lock_3B(void) HARDIRQ_DISABLE(); spin_lock(&lock_A); - local_lock_acquire(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */ - local_lock_release(&local_A); + local_lock(&local_A); /* IN-IRQ <-> IRQ-ON cycle only if we count local_lock(), false */ + local_unlock(&local_A); spin_unlock(&lock_A); HARDIRQ_ENABLE(); @@ -2812,7 +2875,7 @@ void locking_selftest(void) printk("------------------------\n"); printk("| Locking API testsuite:\n"); printk("----------------------------------------------------------------------------\n"); - printk(" | spin |wlock |rlock |mutex | wsem | rsem |\n"); + printk(" | spin |wlock |rlock |mutex | wsem | rsem |rtmutex\n"); printk(" --------------------------------------------------------------------------\n"); init_shared_classes(); @@ -2885,12 +2948,11 @@ void locking_selftest(void) DO_TESTCASE_6x1RR("rlock W1R2/R2R3/W3W1", W1R2_R2R3_W3W1); printk(" --------------------------------------------------------------------------\n"); - /* * irq-context testcases: */ DO_TESTCASE_2x6("irqs-on + irq-safe-A", irqsafe1); - DO_TESTCASE_2x3("sirq-safe-A => hirqs-on", irqsafe2A); + NON_RT(DO_TESTCASE_2x3("sirq-safe-A => hirqs-on", irqsafe2A)); DO_TESTCASE_2x6("safe-A + irqs-on", irqsafe2B); DO_TESTCASE_6x6("safe-A + unsafe-B #1", irqsafe3); DO_TESTCASE_6x6("safe-A + unsafe-B #2", irqsafe4); diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c index 8abe1870dba4..0dda04784f8a 100644 --- a/lib/nmi_backtrace.c +++ b/lib/nmi_backtrace.c @@ -75,12 +75,6 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, touch_softlockup_watchdog(); } - /* - * Force flush any remote buffers that might be stuck in IRQ context - * and therefore could not run their irq_work. - */ - printk_safe_flush(); - clear_bit_unlock(0, &backtrace_flag); put_cpu(); } @@ -92,17 +86,24 @@ module_param(backtrace_idle, bool, 0644); bool nmi_cpu_backtrace(struct pt_regs *regs) { int cpu = smp_processor_id(); + unsigned long flags; if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { if (!READ_ONCE(backtrace_idle) && regs && cpu_in_idle(instruction_pointer(regs))) { pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n", cpu, (void *)instruction_pointer(regs)); } else { + /* + * Allow nested NMI backtraces while serializing + * against other CPUs. + */ + raw_printk_cpu_lock_irqsave(flags); pr_warn("NMI backtrace for cpu %d\n", cpu); if (regs) show_regs(regs); else dump_stack(); + raw_printk_cpu_unlock_irqrestore(flags); } cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); return true; diff --git a/lib/ratelimit.c b/lib/ratelimit.c index e01a93f46f83..524cf65dce53 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -47,9 +47,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func) if (time_is_before_jiffies(rs->begin + rs->interval)) { if (rs->missed) { if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) { - printk_deferred(KERN_WARNING - "%s: %d callbacks suppressed\n", - func, rs->missed); + pr_warn("%s: %d callbacks suppressed\n", func, rs->missed); rs->missed = 0; } } diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 27efa6178153..d5cd169e87a2 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -892,7 +892,7 @@ void sg_miter_stop(struct sg_mapping_iter *miter) flush_kernel_dcache_page(miter->page); if (miter->__flags & SG_MITER_ATOMIC) { - WARN_ON_ONCE(preemptible()); + WARN_ON_ONCE(!pagefault_disabled()); kunmap_atomic(miter->addr); } else kunmap(miter->page); diff --git a/lib/test_lockup.c b/lib/test_lockup.c index 864554e76973..906b598740a7 100644 --- a/lib/test_lockup.c +++ b/lib/test_lockup.c @@ -485,13 +485,13 @@ static int __init test_lockup_init(void) offsetof(spinlock_t, lock.wait_lock.magic), SPINLOCK_MAGIC) || test_magic(lock_rwlock_ptr, - offsetof(rwlock_t, rtmutex.wait_lock.magic), + offsetof(rwlock_t, rwbase.rtmutex.wait_lock.magic), SPINLOCK_MAGIC) || test_magic(lock_mutex_ptr, - offsetof(struct mutex, lock.wait_lock.magic), + offsetof(struct mutex, rtmutex.wait_lock.magic), SPINLOCK_MAGIC) || test_magic(lock_rwsem_ptr, - offsetof(struct rw_semaphore, rtmutex.wait_lock.magic), + offsetof(struct rw_semaphore, rwbase.rtmutex.wait_lock.magic), SPINLOCK_MAGIC)) return -EINVAL; #else @@ -502,7 +502,7 @@ static int __init test_lockup_init(void) offsetof(rwlock_t, magic), RWLOCK_MAGIC) || test_magic(lock_mutex_ptr, - offsetof(struct mutex, wait_lock.rlock.magic), + offsetof(struct mutex, wait_lock.magic), SPINLOCK_MAGIC) || test_magic(lock_rwsem_ptr, offsetof(struct rw_semaphore, wait_lock.magic), diff --git a/localversion-rt b/localversion-rt new file mode 100644 index 000000000000..6c6cde1c29e3 --- /dev/null +++ b/localversion-rt @@ -0,0 +1 @@ +-rt21 diff --git a/mm/Kconfig b/mm/Kconfig index 40a9bfcd5062..b6ad15177d27 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -374,7 +374,7 @@ config NOMMU_INITIAL_TRIM_EXCESS config TRANSPARENT_HUGEPAGE bool "Transparent Hugepage Support" - depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE + depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT select COMPACTION select XARRAY_MULTI help diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7db847fa62f8..f5595947d430 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3166,9 +3166,9 @@ static void drain_local_pages_wq(struct work_struct *work) * cpu which is alright but we also have to make sure to not move to * a different one. */ - preempt_disable(); + migrate_disable(); drain_local_pages(drain->zone); - preempt_enable(); + migrate_enable(); } /* diff --git a/mm/shmem.c b/mm/shmem.c index dacda7463d54..7eec13e39ac3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -278,10 +278,10 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) ino_t ino; if (!(sb->s_flags & SB_KERNMOUNT)) { - spin_lock(&sbinfo->stat_lock); + raw_spin_lock(&sbinfo->stat_lock); if (sbinfo->max_inodes) { if (!sbinfo->free_inodes) { - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); return -ENOSPC; } sbinfo->free_inodes--; @@ -304,7 +304,7 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) } *inop = ino; } - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); } else if (inop) { /* * __shmem_file_setup, one of our callers, is lock-free: it @@ -319,13 +319,14 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) * to worry about things like glibc compatibility. */ ino_t *next_ino; + next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu()); ino = *next_ino; if (unlikely(ino % SHMEM_INO_BATCH == 0)) { - spin_lock(&sbinfo->stat_lock); + raw_spin_lock(&sbinfo->stat_lock); ino = sbinfo->next_ino; sbinfo->next_ino += SHMEM_INO_BATCH; - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); if (unlikely(is_zero_ino(ino))) ino++; } @@ -341,9 +342,9 @@ static void shmem_free_inode(struct super_block *sb) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); if (sbinfo->max_inodes) { - spin_lock(&sbinfo->stat_lock); + raw_spin_lock(&sbinfo->stat_lock); sbinfo->free_inodes++; - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); } } @@ -1453,10 +1454,10 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) { struct mempolicy *mpol = NULL; if (sbinfo->mpol) { - spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ + raw_spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ mpol = sbinfo->mpol; mpol_get(mpol); - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); } return mpol; } @@ -3488,9 +3489,10 @@ static int shmem_reconfigure(struct fs_context *fc) struct shmem_options *ctx = fc->fs_private; struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb); unsigned long inodes; + struct mempolicy *mpol = NULL; const char *err; - spin_lock(&sbinfo->stat_lock); + raw_spin_lock(&sbinfo->stat_lock); inodes = sbinfo->max_inodes - sbinfo->free_inodes; if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) { if (!sbinfo->max_blocks) { @@ -3535,14 +3537,15 @@ static int shmem_reconfigure(struct fs_context *fc) * Preserve previous mempolicy unless mpol remount option was specified. */ if (ctx->mpol) { - mpol_put(sbinfo->mpol); + mpol = sbinfo->mpol; sbinfo->mpol = ctx->mpol; /* transfers initial ref */ ctx->mpol = NULL; } - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); + mpol_put(mpol); return 0; out: - spin_unlock(&sbinfo->stat_lock); + raw_spin_unlock(&sbinfo->stat_lock); return invalfc(fc, "%s", err); } @@ -3659,7 +3662,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) sbinfo->mpol = ctx->mpol; ctx->mpol = NULL; - spin_lock_init(&sbinfo->stat_lock); + raw_spin_lock_init(&sbinfo->stat_lock); if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) goto failed; spin_lock_init(&sbinfo->shrinklist_lock); diff --git a/mm/slab_common.c b/mm/slab_common.c index 1c673c323baf..ec2bb0beed75 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -502,6 +502,7 @@ void kmem_cache_destroy(struct kmem_cache *s) if (unlikely(!s)) return; + cpus_read_lock(); mutex_lock(&slab_mutex); s->refcount--; @@ -516,6 +517,7 @@ void kmem_cache_destroy(struct kmem_cache *s) } out_unlock: mutex_unlock(&slab_mutex); + cpus_read_unlock(); } EXPORT_SYMBOL(kmem_cache_destroy); diff --git a/mm/slub.c b/mm/slub.c index 1d2587d9dbfd..7b9bb9e3ac84 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -46,13 +46,21 @@ /* * Lock order: * 1. slab_mutex (Global Mutex) - * 2. node->list_lock - * 3. slab_lock(page) (Only on some arches and for debugging) + * 2. node->list_lock (Spinlock) + * 3. kmem_cache->cpu_slab->lock (Local lock) + * 4. slab_lock(page) (Only on some arches or for debugging) + * 5. object_map_lock (Only for debugging) * * slab_mutex * * The role of the slab_mutex is to protect the list of all the slabs * and to synchronize major metadata changes to slab cache structures. + * Also synchronizes memory hotplug callbacks. + * + * slab_lock + * + * The slab_lock is a wrapper around the page lock, thus it is a bit + * spinlock. * * The slab_lock is only used for debugging and on arches that do not * have the ability to do a cmpxchg_double. It only protects: @@ -61,6 +69,8 @@ * C. page->objects -> Number of objects in page * D. page->frozen -> frozen state * + * Frozen slabs + * * If a slab is frozen then it is exempt from list management. It is not * on any list except per cpu partial list. The processor that froze the * slab is the one who can perform list operations on the page. Other @@ -68,6 +78,8 @@ * froze the slab is the only one that can retrieve the objects from the * page's freelist. * + * list_lock + * * The list_lock protects the partial and full list on each node and * the partial slab counter. If taken then no new slabs may be added or * removed from the lists nor make the number of partial slabs be modified. @@ -79,10 +91,36 @@ * slabs, operations can continue without any centralized lock. F.e. * allocating a long series of objects that fill up slabs does not require * the list lock. - * Interrupts are disabled during allocation and deallocation in order to - * make the slab allocator safe to use in the context of an irq. In addition - * interrupts are disabled to ensure that the processor does not change - * while handling per_cpu slabs, due to kernel preemption. + * + * cpu_slab->lock local lock + * + * This locks protect slowpath manipulation of all kmem_cache_cpu fields + * except the stat counters. This is a percpu structure manipulated only by + * the local cpu, so the lock protects against being preempted or interrupted + * by an irq. Fast path operations rely on lockless operations instead. + * On PREEMPT_RT, the local lock does not actually disable irqs (and thus + * prevent the lockless operations), so fastpath operations also need to take + * the lock and are no longer lockless. + * + * lockless fastpaths + * + * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free()) + * are fully lockless when satisfied from the percpu slab (and when + * cmpxchg_double is possible to use, otherwise slab_lock is taken). + * They also don't disable preemption or migration or irqs. They rely on + * the transaction id (tid) field to detect being preempted or moved to + * another cpu. + * + * irq, preemption, migration considerations + * + * Interrupts are disabled as part of list_lock or local_lock operations, or + * around the slab_lock operation, in order to make the slab allocator safe + * to use in the context of an irq. + * + * In addition, preemption (or migration on PREEMPT_RT) is disabled in the + * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the + * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer + * doesn't have to be revalidated in each section protected by the local lock. * * SLUB assigns one slab for allocation to each processor. * Allocations only occur from these slabs called cpu slabs. @@ -118,6 +156,26 @@ * the fast path and disables lockless freelists. */ +/* + * We could simply use migrate_disable()/enable() but as long as it's a + * function call even on !PREEMPT_RT, use inline preempt_disable() there. + */ +#ifndef CONFIG_PREEMPT_RT +#define slub_get_cpu_ptr(var) get_cpu_ptr(var) +#define slub_put_cpu_ptr(var) put_cpu_ptr(var) +#else +#define slub_get_cpu_ptr(var) \ +({ \ + migrate_disable(); \ + this_cpu_ptr(var); \ +}) +#define slub_put_cpu_ptr(var) \ +do { \ + (void)(var); \ + migrate_enable(); \ +} while (0) +#endif + #ifdef CONFIG_SLUB_DEBUG #ifdef CONFIG_SLUB_DEBUG_ON DEFINE_STATIC_KEY_TRUE(slub_debug_enabled); @@ -359,25 +417,44 @@ static inline unsigned int oo_objects(struct kmem_cache_order_objects x) /* * Per slab locking using the pagelock */ -static __always_inline void slab_lock(struct page *page) +static __always_inline void __slab_lock(struct page *page) { VM_BUG_ON_PAGE(PageTail(page), page); bit_spin_lock(PG_locked, &page->flags); } -static __always_inline void slab_unlock(struct page *page) +static __always_inline void __slab_unlock(struct page *page) { VM_BUG_ON_PAGE(PageTail(page), page); __bit_spin_unlock(PG_locked, &page->flags); } -/* Interrupts must be disabled (for the fallback code to work right) */ +static __always_inline void slab_lock(struct page *page, unsigned long *flags) +{ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_save(*flags); + __slab_lock(page); +} + +static __always_inline void slab_unlock(struct page *page, unsigned long *flags) +{ + __slab_unlock(page); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_restore(*flags); +} + +/* + * Interrupts must be disabled (for the fallback code to work right), typically + * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different + * so we disable interrupts as part of slab_[un]lock(). + */ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page, void *freelist_old, unsigned long counters_old, void *freelist_new, unsigned long counters_new, const char *n) { - VM_BUG_ON(!irqs_disabled()); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + lockdep_assert_irqs_disabled(); #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) if (s->flags & __CMPXCHG_DOUBLE) { @@ -388,15 +465,18 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page } else #endif { - slab_lock(page); + /* init to 0 to prevent spurious warnings */ + unsigned long flags = 0; + + slab_lock(page, &flags); if (page->freelist == freelist_old && page->counters == counters_old) { page->freelist = freelist_new; page->counters = counters_new; - slab_unlock(page); + slab_unlock(page, &flags); return true; } - slab_unlock(page); + slab_unlock(page, &flags); } cpu_relax(); @@ -427,16 +507,16 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, unsigned long flags; local_irq_save(flags); - slab_lock(page); + __slab_lock(page); if (page->freelist == freelist_old && page->counters == counters_old) { page->freelist = freelist_new; page->counters = counters_new; - slab_unlock(page); + __slab_unlock(page); local_irq_restore(flags); return true; } - slab_unlock(page); + __slab_unlock(page); local_irq_restore(flags); } @@ -452,7 +532,19 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, #ifdef CONFIG_SLUB_DEBUG static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; -static DEFINE_SPINLOCK(object_map_lock); +static DEFINE_RAW_SPINLOCK(object_map_lock); + +static void __fill_map(unsigned long *obj_map, struct kmem_cache *s, + struct page *page) +{ + void *addr = page_address(page); + void *p; + + bitmap_zero(obj_map, page->objects); + + for (p = page->freelist; p; p = get_freepointer(s, p)) + set_bit(__obj_to_index(s, addr, p), obj_map); +} #if IS_ENABLED(CONFIG_KUNIT) static bool slab_add_kunit_errors(void) @@ -483,17 +575,11 @@ static inline bool slab_add_kunit_errors(void) { return false; } static unsigned long *get_map(struct kmem_cache *s, struct page *page) __acquires(&object_map_lock) { - void *p; - void *addr = page_address(page); - VM_BUG_ON(!irqs_disabled()); - spin_lock(&object_map_lock); + raw_spin_lock(&object_map_lock); - bitmap_zero(object_map, page->objects); - - for (p = page->freelist; p; p = get_freepointer(s, p)) - set_bit(__obj_to_index(s, addr, p), object_map); + __fill_map(object_map, s, page); return object_map; } @@ -501,7 +587,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) static void put_map(unsigned long *map) __releases(&object_map_lock) { VM_BUG_ON(map != object_map); - spin_unlock(&object_map_lock); + raw_spin_unlock(&object_map_lock); } static inline unsigned int size_from_object(struct kmem_cache *s) @@ -1003,8 +1089,6 @@ static int check_slab(struct kmem_cache *s, struct page *page) { int maxobj; - VM_BUG_ON(!irqs_disabled()); - if (!PageSlab(page)) { slab_err(s, page, "Not a valid slab page"); return 0; @@ -1265,11 +1349,11 @@ static noinline int free_debug_processing( struct kmem_cache_node *n = get_node(s, page_to_nid(page)); void *object = head; int cnt = 0; - unsigned long flags; + unsigned long flags, flags2; int ret = 0; spin_lock_irqsave(&n->list_lock, flags); - slab_lock(page); + slab_lock(page, &flags2); if (s->flags & SLAB_CONSISTENCY_CHECKS) { if (!check_slab(s, page)) @@ -1302,7 +1386,7 @@ out: slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n", bulk_cnt, cnt); - slab_unlock(page); + slab_unlock(page, &flags2); spin_unlock_irqrestore(&n->list_lock, flags); if (!ret) slab_fix(s, "Object at 0x%p not freed", object); @@ -1585,20 +1669,8 @@ static __always_inline bool slab_free_hook(struct kmem_cache *s, { kmemleak_free_recursive(x, s->flags); - /* - * Trouble is that we may no longer disable interrupts in the fast path - * So in order to make the debug calls that expect irqs to be - * disabled we need to disable interrupts temporarily. - */ -#ifdef CONFIG_LOCKDEP - { - unsigned long flags; + debug_check_no_locks_freed(x, s->object_size); - local_irq_save(flags); - debug_check_no_locks_freed(x, s->object_size); - local_irq_restore(flags); - } -#endif if (!(s->flags & SLAB_DEBUG_OBJECTS)) debug_check_no_obj_freed(x, s->object_size); @@ -1822,9 +1894,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) flags &= gfp_allowed_mask; - if (gfpflags_allow_blocking(flags)) - local_irq_enable(); - flags |= s->allocflags; /* @@ -1883,8 +1952,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) page->frozen = 1; out: - if (gfpflags_allow_blocking(flags)) - local_irq_disable(); if (!page) return NULL; @@ -1898,6 +1965,8 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) if (unlikely(flags & GFP_SLAB_BUG_MASK)) flags = kmalloc_fix_flags(flags); + WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); + return allocate_slab(s, flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); } @@ -2021,18 +2090,24 @@ static inline void *acquire_slab(struct kmem_cache *s, return freelist; } +#ifdef CONFIG_SLUB_CPU_PARTIAL static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain); +#else +static inline void put_cpu_partial(struct kmem_cache *s, struct page *page, + int drain) { } +#endif static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags); /* * Try to allocate a partial slab from a specific node. */ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, - struct kmem_cache_cpu *c, gfp_t flags) + struct page **ret_page, gfp_t gfpflags) { struct page *page, *page2; void *object = NULL; unsigned int available = 0; + unsigned long flags; int objects; /* @@ -2044,11 +2119,11 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, if (!n || !n->nr_partial) return NULL; - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry_safe(page, page2, &n->partial, slab_list) { void *t; - if (!pfmemalloc_match(page, flags)) + if (!pfmemalloc_match(page, gfpflags)) continue; t = acquire_slab(s, n, page, object == NULL, &objects); @@ -2057,7 +2132,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, available += objects; if (!object) { - c->page = page; + *ret_page = page; stat(s, ALLOC_FROM_PARTIAL); object = t; } else { @@ -2069,7 +2144,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, break; } - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); return object; } @@ -2077,7 +2152,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, * Get a page from somewhere. Search in increasing NUMA distances. */ static void *get_any_partial(struct kmem_cache *s, gfp_t flags, - struct kmem_cache_cpu *c) + struct page **ret_page) { #ifdef CONFIG_NUMA struct zonelist *zonelist; @@ -2119,7 +2194,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags, if (n && cpuset_zone_allowed(zone, flags) && n->nr_partial > s->min_partial) { - object = get_partial_node(s, n, c, flags); + object = get_partial_node(s, n, ret_page, flags); if (object) { /* * Don't check read_mems_allowed_retry() @@ -2141,7 +2216,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags, * Get a partial page, lock it and return it. */ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, - struct kmem_cache_cpu *c) + struct page **ret_page) { void *object; int searchnode = node; @@ -2149,11 +2224,11 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, if (node == NUMA_NO_NODE) searchnode = numa_mem_id(); - object = get_partial_node(s, get_node(s, searchnode), c, flags); + object = get_partial_node(s, get_node(s, searchnode), ret_page, flags); if (object || node != NUMA_NO_NODE) return object; - return get_any_partial(s, flags, c); + return get_any_partial(s, flags, ret_page); } #ifdef CONFIG_PREEMPTION @@ -2220,16 +2295,23 @@ static inline void note_cmpxchg_failure(const char *n, static void init_kmem_cache_cpus(struct kmem_cache *s) { int cpu; + struct kmem_cache_cpu *c; - for_each_possible_cpu(cpu) - per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu); + for_each_possible_cpu(cpu) { + c = per_cpu_ptr(s->cpu_slab, cpu); + local_lock_init(&c->lock); + c->tid = init_tid(cpu); + } } /* - * Remove the cpu slab + * Finishes removing the cpu slab. Merges cpu's freelist with page's freelist, + * unfreezes the slabs and puts it on the proper list. + * Assumes the slab has been already safely taken away from kmem_cache_cpu + * by the caller. */ static void deactivate_slab(struct kmem_cache *s, struct page *page, - void *freelist, struct kmem_cache_cpu *c) + void *freelist) { enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE }; struct kmem_cache_node *n = get_node(s, page_to_nid(page)); @@ -2237,6 +2319,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, enum slab_modes l = M_NONE, m = M_NONE; void *nextfree, *freelist_iter, *freelist_tail; int tail = DEACTIVATE_TO_HEAD; + unsigned long flags = 0; struct page new; struct page old; @@ -2312,7 +2395,7 @@ redo: * that acquire_slab() will see a slab page that * is frozen */ - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); } } else { m = M_FULL; @@ -2323,7 +2406,7 @@ redo: * slabs from diagnostic functions will not see * any frozen slabs. */ - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); } } @@ -2340,14 +2423,14 @@ redo: } l = m; - if (!__cmpxchg_double_slab(s, page, + if (!cmpxchg_double_slab(s, page, old.freelist, old.counters, new.freelist, new.counters, "unfreezing slab")) goto redo; if (lock) - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); if (m == M_PARTIAL) stat(s, tail); @@ -2358,38 +2441,29 @@ redo: discard_slab(s, page); stat(s, FREE_SLAB); } - - c->page = NULL; - c->freelist = NULL; } -/* - * Unfreeze all the cpu partial slabs. - * - * This function must be called with interrupts disabled - * for the cpu using c (or some other guarantee must be there - * to guarantee no concurrent accesses). - */ -static void unfreeze_partials(struct kmem_cache *s, - struct kmem_cache_cpu *c) -{ #ifdef CONFIG_SLUB_CPU_PARTIAL +static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page) +{ struct kmem_cache_node *n = NULL, *n2 = NULL; struct page *page, *discard_page = NULL; + unsigned long flags = 0; - while ((page = slub_percpu_partial(c))) { + while (partial_page) { struct page new; struct page old; - slub_set_percpu_partial(c, page); + page = partial_page; + partial_page = page->next; n2 = get_node(s, page_to_nid(page)); if (n != n2) { if (n) - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); n = n2; - spin_lock(&n->list_lock); + spin_lock_irqsave(&n->list_lock, flags); } do { @@ -2418,7 +2492,7 @@ static void unfreeze_partials(struct kmem_cache *s, } if (n) - spin_unlock(&n->list_lock); + spin_unlock_irqrestore(&n->list_lock, flags); while (discard_page) { page = discard_page; @@ -2428,7 +2502,35 @@ static void unfreeze_partials(struct kmem_cache *s, discard_slab(s, page); stat(s, FREE_SLAB); } -#endif /* CONFIG_SLUB_CPU_PARTIAL */ +} + +/* + * Unfreeze all the cpu partial slabs. + */ +static void unfreeze_partials(struct kmem_cache *s) +{ + struct page *partial_page; + unsigned long flags; + + local_lock_irqsave(&s->cpu_slab->lock, flags); + partial_page = this_cpu_read(s->cpu_slab->partial); + this_cpu_write(s->cpu_slab->partial, NULL); + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + + if (partial_page) + __unfreeze_partials(s, partial_page); +} + +static void unfreeze_partials_cpu(struct kmem_cache *s, + struct kmem_cache_cpu *c) +{ + struct page *partial_page; + + partial_page = slub_percpu_partial(c); + c->partial = NULL; + + if (partial_page) + __unfreeze_partials(s, partial_page); } /* @@ -2440,97 +2542,170 @@ static void unfreeze_partials(struct kmem_cache *s, */ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) { -#ifdef CONFIG_SLUB_CPU_PARTIAL struct page *oldpage; - int pages; - int pobjects; + struct page *page_to_unfreeze = NULL; + unsigned long flags; + int pages = 0; + int pobjects = 0; - preempt_disable(); - do { - pages = 0; - pobjects = 0; - oldpage = this_cpu_read(s->cpu_slab->partial); + local_lock_irqsave(&s->cpu_slab->lock, flags); + + oldpage = this_cpu_read(s->cpu_slab->partial); - if (oldpage) { + if (oldpage) { + if (drain && oldpage->pobjects > slub_cpu_partial(s)) { + /* + * Partial array is full. Move the existing set to the + * per node partial list. Postpone the actual unfreezing + * outside of the critical section. + */ + page_to_unfreeze = oldpage; + oldpage = NULL; + } else { pobjects = oldpage->pobjects; pages = oldpage->pages; - if (drain && pobjects > slub_cpu_partial(s)) { - unsigned long flags; - /* - * partial array is full. Move the existing - * set to the per node partial list. - */ - local_irq_save(flags); - unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); - local_irq_restore(flags); - oldpage = NULL; - pobjects = 0; - pages = 0; - stat(s, CPU_PARTIAL_DRAIN); - } } + } - pages++; - pobjects += page->objects - page->inuse; + pages++; + pobjects += page->objects - page->inuse; - page->pages = pages; - page->pobjects = pobjects; - page->next = oldpage; + page->pages = pages; + page->pobjects = pobjects; + page->next = oldpage; - } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) - != oldpage); - if (unlikely(!slub_cpu_partial(s))) { - unsigned long flags; + this_cpu_write(s->cpu_slab->partial, page); - local_irq_save(flags); - unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); - local_irq_restore(flags); + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + + if (page_to_unfreeze) { + __unfreeze_partials(s, page_to_unfreeze); + stat(s, CPU_PARTIAL_DRAIN); } - preempt_enable(); -#endif /* CONFIG_SLUB_CPU_PARTIAL */ } +#else /* CONFIG_SLUB_CPU_PARTIAL */ + +static inline void unfreeze_partials(struct kmem_cache *s) { } +static inline void unfreeze_partials_cpu(struct kmem_cache *s, + struct kmem_cache_cpu *c) { } + +#endif /* CONFIG_SLUB_CPU_PARTIAL */ + static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) { - stat(s, CPUSLAB_FLUSH); - deactivate_slab(s, c->page, c->freelist, c); + unsigned long flags; + struct page *page; + void *freelist; + + local_lock_irqsave(&s->cpu_slab->lock, flags); + + page = c->page; + freelist = c->freelist; + + c->page = NULL; + c->freelist = NULL; + c->tid = next_tid(c->tid); + + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + + if (page) { + deactivate_slab(s, page, freelist); + stat(s, CPUSLAB_FLUSH); + } +} + +static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) +{ + struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); + void *freelist = c->freelist; + struct page *page = c->page; + c->page = NULL; + c->freelist = NULL; c->tid = next_tid(c->tid); + + if (page) { + deactivate_slab(s, page, freelist); + stat(s, CPUSLAB_FLUSH); + } + + unfreeze_partials_cpu(s, c); } +struct slub_flush_work { + struct work_struct work; + struct kmem_cache *s; + bool skip; +}; + /* * Flush cpu slab. * - * Called from IPI handler with interrupts disabled. + * Called from CPU work handler with migration disabled. */ -static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) +static void flush_cpu_slab(struct work_struct *w) { - struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); + struct kmem_cache *s; + struct kmem_cache_cpu *c; + struct slub_flush_work *sfw; + + sfw = container_of(w, struct slub_flush_work, work); + + s = sfw->s; + c = this_cpu_ptr(s->cpu_slab); if (c->page) flush_slab(s, c); - unfreeze_partials(s, c); + unfreeze_partials(s); } -static void flush_cpu_slab(void *d) +static bool has_cpu_slab(int cpu, struct kmem_cache *s) { - struct kmem_cache *s = d; + struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); - __flush_cpu_slab(s, smp_processor_id()); + return c->page || slub_percpu_partial(c); } -static bool has_cpu_slab(int cpu, void *info) +static DEFINE_MUTEX(flush_lock); +static DEFINE_PER_CPU(struct slub_flush_work, slub_flush); + +static void flush_all_cpus_locked(struct kmem_cache *s) { - struct kmem_cache *s = info; - struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); + struct slub_flush_work *sfw; + unsigned int cpu; - return c->page || slub_percpu_partial(c); + lockdep_assert_cpus_held(); + mutex_lock(&flush_lock); + + for_each_online_cpu(cpu) { + sfw = &per_cpu(slub_flush, cpu); + if (!has_cpu_slab(cpu, s)) { + sfw->skip = true; + continue; + } + INIT_WORK(&sfw->work, flush_cpu_slab); + sfw->skip = false; + sfw->s = s; + schedule_work_on(cpu, &sfw->work); + } + + for_each_online_cpu(cpu) { + sfw = &per_cpu(slub_flush, cpu); + if (sfw->skip) + continue; + flush_work(&sfw->work); + } + + mutex_unlock(&flush_lock); } static void flush_all(struct kmem_cache *s) { - on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1); + cpus_read_lock(); + flush_all_cpus_locked(s); + cpus_read_unlock(); } /* @@ -2540,14 +2715,10 @@ static void flush_all(struct kmem_cache *s) static int slub_cpu_dead(unsigned int cpu) { struct kmem_cache *s; - unsigned long flags; mutex_lock(&slab_mutex); - list_for_each_entry(s, &slab_caches, list) { - local_irq_save(flags); + list_for_each_entry(s, &slab_caches, list) __flush_cpu_slab(s, cpu); - local_irq_restore(flags); - } mutex_unlock(&slab_mutex); return 0; } @@ -2630,44 +2801,22 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) #endif } -static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, - int node, struct kmem_cache_cpu **pc) +static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags) { - void *freelist; - struct kmem_cache_cpu *c = *pc; - struct page *page; - - WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); - - freelist = get_partial(s, flags, node, c); - - if (freelist) - return freelist; - - page = new_slab(s, flags, node); - if (page) { - c = raw_cpu_ptr(s->cpu_slab); - if (c->page) - flush_slab(s, c); - - /* - * No other reference to the page yet so we can - * muck around with it freely without cmpxchg - */ - freelist = page->freelist; - page->freelist = NULL; - - stat(s, ALLOC_SLAB); - c->page = page; - *pc = c; - } + if (unlikely(PageSlabPfmemalloc(page))) + return gfp_pfmemalloc_allowed(gfpflags); - return freelist; + return true; } -static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags) +/* + * A variant of pfmemalloc_match() that tests page flags without asserting + * PageSlab. Intended for opportunistic checks before taking a lock and + * rechecking that nobody else freed the page under us. + */ +static inline bool pfmemalloc_match_unsafe(struct page *page, gfp_t gfpflags) { - if (unlikely(PageSlabPfmemalloc(page))) + if (unlikely(__PageSlabPfmemalloc(page))) return gfp_pfmemalloc_allowed(gfpflags); return true; @@ -2680,8 +2829,6 @@ static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags) * The page is still frozen if the return value is not NULL. * * If this function returns NULL then the page has been unfrozen. - * - * This function must be called with interrupt disabled. */ static inline void *get_freelist(struct kmem_cache *s, struct page *page) { @@ -2689,6 +2836,8 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page) unsigned long counters; void *freelist; + lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock)); + do { freelist = page->freelist; counters = page->counters; @@ -2723,7 +2872,7 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page) * we need to allocate a new slab. This is the slowest path since it involves * a call to the page allocator and the setup of a new slab. * - * Version of __slab_alloc to use when we know that interrupts are + * Version of __slab_alloc to use when we know that preemption is * already disabled (which is the case for bulk allocation). */ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, @@ -2731,10 +2880,13 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, { void *freelist; struct page *page; + unsigned long flags; stat(s, ALLOC_SLOWPATH); - page = c->page; +reread_page: + + page = READ_ONCE(c->page); if (!page) { /* * if the node is not online or has no normal memory, just @@ -2757,8 +2909,7 @@ redo: goto redo; } else { stat(s, ALLOC_NODE_MISMATCH); - deactivate_slab(s, page, c->freelist, c); - goto new_slab; + goto deactivate_slab; } } @@ -2767,12 +2918,15 @@ redo: * PFMEMALLOC but right now, we are losing the pfmemalloc * information when the page leaves the per-cpu allocator */ - if (unlikely(!pfmemalloc_match(page, gfpflags))) { - deactivate_slab(s, page, c->freelist, c); - goto new_slab; + if (unlikely(!pfmemalloc_match_unsafe(page, gfpflags))) + goto deactivate_slab; + + /* must check again c->page in case we got preempted and it changed */ + local_lock_irqsave(&s->cpu_slab->lock, flags); + if (unlikely(page != c->page)) { + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + goto reread_page; } - - /* must check again c->freelist in case of cpu migration or IRQ */ freelist = c->freelist; if (freelist) goto load_freelist; @@ -2781,6 +2935,7 @@ redo: if (!freelist) { c->page = NULL; + local_unlock_irqrestore(&s->cpu_slab->lock, flags); stat(s, DEACTIVATE_BYPASS); goto new_slab; } @@ -2788,6 +2943,9 @@ redo: stat(s, ALLOC_REFILL); load_freelist: + + lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock)); + /* * freelist is pointing to the list of objects to be used. * page is pointing to the page from which the objects are obtained. @@ -2796,59 +2954,141 @@ load_freelist: VM_BUG_ON(!c->page->frozen); c->freelist = get_freepointer(s, freelist); c->tid = next_tid(c->tid); + local_unlock_irqrestore(&s->cpu_slab->lock, flags); return freelist; +deactivate_slab: + + local_lock_irqsave(&s->cpu_slab->lock, flags); + if (page != c->page) { + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + goto reread_page; + } + freelist = c->freelist; + c->page = NULL; + c->freelist = NULL; + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + deactivate_slab(s, page, freelist); + new_slab: if (slub_percpu_partial(c)) { + local_lock_irqsave(&s->cpu_slab->lock, flags); + if (unlikely(c->page)) { + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + goto reread_page; + } + if (unlikely(!slub_percpu_partial(c))) { + local_unlock_irqrestore(&s->cpu_slab->lock, flags); + /* we were preempted and partial list got empty */ + goto new_objects; + } + page = c->page = slub_percpu_partial(c); slub_set_percpu_partial(c, page); + local_unlock_irqrestore(&s->cpu_slab->lock, flags); stat(s, CPU_PARTIAL_ALLOC); goto redo; } - freelist = new_slab_objects(s, gfpflags, node, &c); +new_objects: + + freelist = get_partial(s, gfpflags, node, &page); + if (freelist) + goto check_new_page; + + slub_put_cpu_ptr(s->cpu_slab); + page = new_slab(s, gfpflags, node); + c = slub_get_cpu_ptr(s->cpu_slab); - if (unlikely(!freelist)) { + if (unlikely(!page)) { slab_out_of_memory(s, gfpflags, node); return NULL; } - page = c->page; - if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags))) - goto load_freelist; + /* + * No other reference to the page yet so we can + * muck around with it freely without cmpxchg + */ + freelist = page->freelist; + page->freelist = NULL; - /* Only entered in the debug case */ - if (kmem_cache_debug(s) && - !alloc_debug_processing(s, page, freelist, addr)) - goto new_slab; /* Slab failed checks. Next slab needed */ + stat(s, ALLOC_SLAB); + +check_new_page: + + if (kmem_cache_debug(s)) { + if (!alloc_debug_processing(s, page, freelist, addr)) { + /* Slab failed checks. Next slab needed */ + goto new_slab; + } else { + /* + * For debug case, we don't load freelist so that all + * allocations go through alloc_debug_processing() + */ + goto return_single; + } + } + + if (unlikely(!pfmemalloc_match(page, gfpflags))) + /* + * For !pfmemalloc_match() case we don't load freelist so that + * we don't make further mismatched allocations easier. + */ + goto return_single; + +retry_load_page: + + local_lock_irqsave(&s->cpu_slab->lock, flags); + if (unlikely(c->page)) { + void *flush_freelist = c->freelist; + struct page *flush_page = c->page; + + c->page = NULL; + c->freelist = NULL; + c->tid = next_tid(c->tid); + + local_unlock_irqrestore(&s->cpu_slab->lock, flags); - deactivate_slab(s, page, get_freepointer(s, freelist), c); + deactivate_slab(s, flush_page, flush_freelist); + + stat(s, CPUSLAB_FLUSH); + + goto retry_load_page; + } + c->page = page; + + goto load_freelist; + +return_single: + + deactivate_slab(s, page, get_freepointer(s, freelist)); return freelist; } /* - * Another one that disabled interrupt and compensates for possible - * cpu changes by refetching the per cpu area pointer. + * A wrapper for ___slab_alloc() for contexts where preemption is not yet + * disabled. Compensates for possible cpu changes by refetching the per cpu area + * pointer. */ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, unsigned long addr, struct kmem_cache_cpu *c) { void *p; - unsigned long flags; - local_irq_save(flags); -#ifdef CONFIG_PREEMPTION +#ifdef CONFIG_PREEMPT_COUNT /* * We may have been preempted and rescheduled on a different - * cpu before disabling interrupts. Need to reload cpu area + * cpu before disabling preemption. Need to reload cpu area * pointer. */ - c = this_cpu_ptr(s->cpu_slab); + c = slub_get_cpu_ptr(s->cpu_slab); #endif p = ___slab_alloc(s, gfpflags, node, addr, c); - local_irq_restore(flags); +#ifdef CONFIG_PREEMPT_COUNT + slub_put_cpu_ptr(s->cpu_slab); +#endif return p; } @@ -2899,15 +3139,14 @@ redo: * reading from one cpu area. That does not matter as long * as we end up on the original cpu again when doing the cmpxchg. * - * We should guarantee that tid and kmem_cache are retrieved on - * the same cpu. It could be different if CONFIG_PREEMPTION so we need - * to check if it is matched or not. + * We must guarantee that tid and kmem_cache_cpu are retrieved on the + * same cpu. We read first the kmem_cache_cpu pointer and use it to read + * the tid. If we are preempted and switched to another cpu between the + * two reads, it's OK as the two are still associated with the same cpu + * and cmpxchg later will validate the cpu. */ - do { - tid = this_cpu_read(s->cpu_slab->tid); - c = raw_cpu_ptr(s->cpu_slab); - } while (IS_ENABLED(CONFIG_PREEMPTION) && - unlikely(tid != READ_ONCE(c->tid))); + c = raw_cpu_ptr(s->cpu_slab); + tid = READ_ONCE(c->tid); /* * Irqless object alloc/free algorithm used here depends on sequence @@ -2928,7 +3167,15 @@ redo: object = c->freelist; page = c->page; - if (unlikely(!object || !page || !node_match(page, node))) { + /* + * We cannot use the lockless fastpath on PREEMPT_RT because if a + * slowpath has taken the local_lock_irqsave(), it is not protected + * against a fast path operation in an irq handler. So we need to take + * the slow path which uses local_lock. It is still relatively fast if + * there is a suitable cpu freelist. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT) || + unlikely(!object || !page || !node_match(page, node))) { object = __slab_alloc(s, gfpflags, node, addr, c); } else { void *next_object = get_freepointer_safe(s, object); @@ -3183,16 +3430,14 @@ redo: * data is retrieved via this pointer. If we are on the same cpu * during the cmpxchg then the free will succeed. */ - do { - tid = this_cpu_read(s->cpu_slab->tid); - c = raw_cpu_ptr(s->cpu_slab); - } while (IS_ENABLED(CONFIG_PREEMPTION) && - unlikely(tid != READ_ONCE(c->tid))); + c = raw_cpu_ptr(s->cpu_slab); + tid = READ_ONCE(c->tid); /* Same with comment on barrier() in slab_alloc_node() */ barrier(); if (likely(page == c->page)) { +#ifndef CONFIG_PREEMPT_RT void **freelist = READ_ONCE(c->freelist); set_freepointer(s, tail_obj, freelist); @@ -3205,6 +3450,31 @@ redo: note_cmpxchg_failure("slab_free", s, tid); goto redo; } +#else /* CONFIG_PREEMPT_RT */ + /* + * We cannot use the lockless fastpath on PREEMPT_RT because if + * a slowpath has taken the local_lock_irqsave(), it is not + * protected against a fast path operation in an irq handler. So + * we need to take the local_lock. We shouldn't simply defer to + * __slab_free() as that wouldn't use the cpu freelist at all. + */ + void **freelist; + + local_lock(&s->cpu_slab->lock); + c = this_cpu_ptr(s->cpu_slab); + if (unlikely(page != c->page)) { + local_unlock(&s->cpu_slab->lock); + goto redo; + } + tid = c->tid; + freelist = c->freelist; + + set_freepointer(s, tail_obj, freelist); + c->freelist = head; + c->tid = next_tid(tid); + + local_unlock(&s->cpu_slab->lock); +#endif stat(s, FREE_FASTPATH); } else __slab_free(s, page, head, tail_obj, cnt, addr); @@ -3382,8 +3652,8 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, * IRQs, which protects against PREEMPT and interrupts * handlers invoking normal fastpath. */ - local_irq_disable(); - c = this_cpu_ptr(s->cpu_slab); + c = slub_get_cpu_ptr(s->cpu_slab); + local_lock_irq(&s->cpu_slab->lock); for (i = 0; i < size; i++) { void *object = kfence_alloc(s, s->object_size, flags); @@ -3404,6 +3674,8 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, */ c->tid = next_tid(c->tid); + local_unlock_irq(&s->cpu_slab->lock); + /* * Invoking slow path likely have side-effect * of re-populating per CPU c->freelist @@ -3416,6 +3688,8 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, c = this_cpu_ptr(s->cpu_slab); maybe_wipe_obj_freeptr(s, p[i]); + local_lock_irq(&s->cpu_slab->lock); + continue; /* goto for-loop */ } c->freelist = get_freepointer(s, object); @@ -3423,7 +3697,8 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, maybe_wipe_obj_freeptr(s, p[i]); } c->tid = next_tid(c->tid); - local_irq_enable(); + local_unlock_irq(&s->cpu_slab->lock); + slub_put_cpu_ptr(s->cpu_slab); /* * memcg and kmem_cache debug support and memory initialization. @@ -3433,7 +3708,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, slab_want_init_on_alloc(flags, s)); return i; error: - local_irq_enable(); + slub_put_cpu_ptr(s->cpu_slab); slab_post_alloc_hook(s, objcg, flags, i, p, false); __kmem_cache_free_bulk(s, i, p); return 0; @@ -3947,11 +4222,12 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, { #ifdef CONFIG_SLUB_DEBUG void *addr = page_address(page); + unsigned long flags; unsigned long *map; void *p; slab_err(s, page, text, s->name); - slab_lock(page); + slab_lock(page, &flags); map = get_map(s, page); for_each_object(p, s, addr, page->objects) { @@ -3962,7 +4238,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, } } put_map(map); - slab_unlock(page); + slab_unlock(page, &flags); #endif } @@ -4012,7 +4288,7 @@ int __kmem_cache_shutdown(struct kmem_cache *s) int node; struct kmem_cache_node *n; - flush_all(s); + flush_all_cpus_locked(s); /* Attempt to free all objects */ for_each_kmem_cache_node(s, node, n) { free_partial(s, n); @@ -4288,7 +4564,7 @@ EXPORT_SYMBOL(kfree); * being allocated from last increasing the chance that the last objects * are freed in them. */ -int __kmem_cache_shrink(struct kmem_cache *s) +static int __kmem_cache_do_shrink(struct kmem_cache *s) { int node; int i; @@ -4300,7 +4576,6 @@ int __kmem_cache_shrink(struct kmem_cache *s) unsigned long flags; int ret = 0; - flush_all(s); for_each_kmem_cache_node(s, node, n) { INIT_LIST_HEAD(&discard); for (i = 0; i < SHRINK_PROMOTE_MAX; i++) @@ -4350,13 +4625,21 @@ int __kmem_cache_shrink(struct kmem_cache *s) return ret; } +int __kmem_cache_shrink(struct kmem_cache *s) +{ + flush_all(s); + return __kmem_cache_do_shrink(s); +} + static int slab_mem_going_offline_callback(void *arg) { struct kmem_cache *s; mutex_lock(&slab_mutex); - list_for_each_entry(s, &slab_caches, list) - __kmem_cache_shrink(s); + list_for_each_entry(s, &slab_caches, list) { + flush_all_cpus_locked(s); + __kmem_cache_do_shrink(s); + } mutex_unlock(&slab_mutex); return 0; @@ -4684,33 +4967,33 @@ static int count_total(struct page *page) #endif #ifdef CONFIG_SLUB_DEBUG -static void validate_slab(struct kmem_cache *s, struct page *page) +static void validate_slab(struct kmem_cache *s, struct page *page, + unsigned long *obj_map) { void *p; void *addr = page_address(page); - unsigned long *map; + unsigned long flags; - slab_lock(page); + slab_lock(page, &flags); if (!check_slab(s, page) || !on_freelist(s, page, NULL)) goto unlock; /* Now we know that a valid freelist exists */ - map = get_map(s, page); + __fill_map(obj_map, s, page); for_each_object(p, s, addr, page->objects) { - u8 val = test_bit(__obj_to_index(s, addr, p), map) ? + u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ? SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; if (!check_object(s, page, p, val)) break; } - put_map(map); unlock: - slab_unlock(page); + slab_unlock(page, &flags); } static int validate_slab_node(struct kmem_cache *s, - struct kmem_cache_node *n) + struct kmem_cache_node *n, unsigned long *obj_map) { unsigned long count = 0; struct page *page; @@ -4719,7 +5002,7 @@ static int validate_slab_node(struct kmem_cache *s, spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, slab_list) { - validate_slab(s, page); + validate_slab(s, page, obj_map); count++; } if (count != n->nr_partial) { @@ -4732,7 +5015,7 @@ static int validate_slab_node(struct kmem_cache *s, goto out; list_for_each_entry(page, &n->full, slab_list) { - validate_slab(s, page); + validate_slab(s, page, obj_map); count++; } if (count != atomic_long_read(&n->nr_slabs)) { @@ -4751,10 +5034,17 @@ long validate_slab_cache(struct kmem_cache *s) int node; unsigned long count = 0; struct kmem_cache_node *n; + unsigned long *obj_map; + + obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL); + if (!obj_map) + return -ENOMEM; flush_all(s); for_each_kmem_cache_node(s, node, n) - count += validate_slab_node(s, n); + count += validate_slab_node(s, n, obj_map); + + bitmap_free(obj_map); return count; } @@ -4890,17 +5180,17 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, } static void process_slab(struct loc_track *t, struct kmem_cache *s, - struct page *page, enum track_item alloc) + struct page *page, enum track_item alloc, + unsigned long *obj_map) { void *addr = page_address(page); void *p; - unsigned long *map; - map = get_map(s, page); + __fill_map(obj_map, s, page); + for_each_object(p, s, addr, page->objects) - if (!test_bit(__obj_to_index(s, addr, p), map)) + if (!test_bit(__obj_to_index(s, addr, p), obj_map)) add_location(t, s, get_track(s, p, alloc)); - put_map(map); } #endif /* CONFIG_DEBUG_FS */ #endif /* CONFIG_SLUB_DEBUG */ @@ -5827,17 +6117,21 @@ static int slab_debug_trace_open(struct inode *inode, struct file *filep) struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops, sizeof(struct loc_track)); struct kmem_cache *s = file_inode(filep)->i_private; + unsigned long *obj_map; + + obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL); + if (!obj_map) + return -ENOMEM; if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0) alloc = TRACK_ALLOC; else alloc = TRACK_FREE; - if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) + if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) { + bitmap_free(obj_map); return -ENOMEM; - - /* Push back cpu slabs */ - flush_all(s); + } for_each_kmem_cache_node(s, node, n) { unsigned long flags; @@ -5848,12 +6142,13 @@ static int slab_debug_trace_open(struct inode *inode, struct file *filep) spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry(page, &n->partial, slab_list) - process_slab(t, s, page, alloc); + process_slab(t, s, page, alloc, obj_map); list_for_each_entry(page, &n->full, slab_list) - process_slab(t, s, page, alloc); + process_slab(t, s, page, alloc, obj_map); spin_unlock_irqrestore(&n->list_lock, flags); } + bitmap_free(obj_map); return 0; } diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d5cd52805149..cf2d9abdd959 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1847,7 +1847,7 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) struct vmap_block *vb; struct vmap_area *va; unsigned long vb_idx; - int node, err; + int node, err, cpu; void *vaddr; node = numa_node_id(); @@ -1884,11 +1884,12 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) return ERR_PTR(err); } - vbq = &get_cpu_var(vmap_block_queue); + cpu = get_cpu_light(); + vbq = this_cpu_ptr(&vmap_block_queue); spin_lock(&vbq->lock); list_add_tail_rcu(&vb->free_list, &vbq->free); spin_unlock(&vbq->lock); - put_cpu_var(vmap_block_queue); + put_cpu_light(); return vaddr; } @@ -1953,6 +1954,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) struct vmap_block *vb; void *vaddr = NULL; unsigned int order; + int cpu; BUG_ON(offset_in_page(size)); BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); @@ -1967,7 +1969,8 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) order = get_order(size); rcu_read_lock(); - vbq = &get_cpu_var(vmap_block_queue); + cpu = get_cpu_light(); + vbq = this_cpu_ptr(&vmap_block_queue); list_for_each_entry_rcu(vb, &vbq->free, free_list) { unsigned long pages_off; @@ -1990,7 +1993,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) break; } - put_cpu_var(vmap_block_queue); + put_cpu_light(); rcu_read_unlock(); /* Allocate new block if nothing was found */ diff --git a/mm/vmstat.c b/mm/vmstat.c index b0534e068166..d06332c221b1 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -319,6 +319,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, long x; long t; + preempt_disable_rt(); x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -328,6 +329,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, x = 0; } __this_cpu_write(*p, x); + preempt_enable_rt(); } EXPORT_SYMBOL(__mod_zone_page_state); @@ -350,6 +352,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, delta >>= PAGE_SHIFT; } + preempt_disable_rt(); x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -359,6 +362,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, x = 0; } __this_cpu_write(*p, x); + preempt_enable_rt(); } EXPORT_SYMBOL(__mod_node_page_state); @@ -391,6 +395,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; + preempt_disable_rt(); v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { @@ -399,6 +404,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) zone_page_state_add(v + overstep, zone, item); __this_cpu_write(*p, -overstep); } + preempt_enable_rt(); } void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) @@ -409,6 +415,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); + preempt_disable_rt(); v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { @@ -417,6 +424,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) node_page_state_add(v + overstep, pgdat, item); __this_cpu_write(*p, -overstep); } + preempt_enable_rt(); } void __inc_zone_page_state(struct page *page, enum zone_stat_item item) @@ -437,6 +445,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item) s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; + preempt_disable_rt(); v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { @@ -445,6 +454,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item) zone_page_state_add(v - overstep, zone, item); __this_cpu_write(*p, overstep); } + preempt_enable_rt(); } void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) @@ -455,6 +465,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); + preempt_disable_rt(); v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { @@ -463,6 +474,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) node_page_state_add(v - overstep, pgdat, item); __this_cpu_write(*p, overstep); } + preempt_enable_rt(); } void __dec_zone_page_state(struct page *page, enum zone_stat_item item) diff --git a/mm/workingset.c b/mm/workingset.c index 5ba3e42446fa..8d2ba861bc74 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -432,6 +432,8 @@ static struct list_lru shadow_nodes; void workingset_update_node(struct xa_node *node) { + struct address_space *mapping; + /* * Track non-empty nodes that contain only shadow entries; * unlink those that contain pages or are being freed. @@ -440,7 +442,8 @@ void workingset_update_node(struct xa_node *node) * already where they should be. The list_empty() test is safe * as node->private_list is protected by the i_pages lock. */ - VM_WARN_ON_ONCE(!irqs_disabled()); /* For __inc_lruvec_page_state */ + mapping = container_of(node->array, struct address_space, i_pages); + lockdep_assert_held(&mapping->i_pages.xa_lock); if (node->count && node->count == node->nr_values) { if (list_empty(&node->private_list)) { diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index b897ce3b399a..4c6a206176bd 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -57,6 +57,7 @@ #include <linux/wait.h> #include <linux/pagemap.h> #include <linux/fs.h> +#include <linux/local_lock.h> #define ZSPAGE_MAGIC 0x58 @@ -77,6 +78,20 @@ #define ZS_HANDLE_SIZE (sizeof(unsigned long)) +#ifdef CONFIG_PREEMPT_RT + +struct zsmalloc_handle { + unsigned long addr; + spinlock_t lock; +}; + +#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle)) + +#else + +#define ZS_HANDLE_ALLOC_SIZE (sizeof(unsigned long)) +#endif + /* * Object location (<PFN>, <obj_idx>) is encoded as * a single (unsigned long) handle value. @@ -293,6 +308,7 @@ struct zspage { }; struct mapping_area { + local_lock_t lock; char *vm_buf; /* copy buffer for objects that span pages */ char *vm_addr; /* address of kmap_atomic()'ed pages */ enum zs_mapmode vm_mm; /* mapping mode */ @@ -322,7 +338,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {} static int create_cache(struct zs_pool *pool) { - pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE, + pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_ALLOC_SIZE, 0, 0, NULL); if (!pool->handle_cachep) return 1; @@ -346,10 +362,27 @@ static void destroy_cache(struct zs_pool *pool) static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp) { - return (unsigned long)kmem_cache_alloc(pool->handle_cachep, - gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); + void *p; + + p = kmem_cache_alloc(pool->handle_cachep, + gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); +#ifdef CONFIG_PREEMPT_RT + if (p) { + struct zsmalloc_handle *zh = p; + + spin_lock_init(&zh->lock); + } +#endif + return (unsigned long)p; } +#ifdef CONFIG_PREEMPT_RT +static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle) +{ + return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1)); +} +#endif + static void cache_free_handle(struct zs_pool *pool, unsigned long handle) { kmem_cache_free(pool->handle_cachep, (void *)handle); @@ -368,12 +401,18 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage) static void record_obj(unsigned long handle, unsigned long obj) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + WRITE_ONCE(zh->addr, obj); +#else /* * lsb of @obj represents handle lock while other bits * represent object value the handle is pointing so * updating shouldn't do store tearing. */ WRITE_ONCE(*(unsigned long *)handle, obj); +#endif } /* zpool driver */ @@ -455,7 +494,10 @@ MODULE_ALIAS("zpool-zsmalloc"); #endif /* CONFIG_ZPOOL */ /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ -static DEFINE_PER_CPU(struct mapping_area, zs_map_area); +static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = { + /* XXX remove this and use a spin_lock_t in pin_tag() */ + .lock = INIT_LOCAL_LOCK(lock), +}; static bool is_zspage_isolated(struct zspage *zspage) { @@ -862,7 +904,13 @@ static unsigned long location_to_obj(struct page *page, unsigned int obj_idx) static unsigned long handle_to_obj(unsigned long handle) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + return zh->addr; +#else return *(unsigned long *)handle; +#endif } static unsigned long obj_to_head(struct page *page, void *obj) @@ -876,22 +924,46 @@ static unsigned long obj_to_head(struct page *page, void *obj) static inline int testpin_tag(unsigned long handle) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + return spin_is_locked(&zh->lock); +#else return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle); +#endif } static inline int trypin_tag(unsigned long handle) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + return spin_trylock(&zh->lock); +#else return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle); +#endif } static void pin_tag(unsigned long handle) __acquires(bitlock) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + return spin_lock(&zh->lock); +#else bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle); +#endif } static void unpin_tag(unsigned long handle) __releases(bitlock) { +#ifdef CONFIG_PREEMPT_RT + struct zsmalloc_handle *zh = zs_get_pure_handle(handle); + + return spin_unlock(&zh->lock); +#else bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle); +#endif } static void reset_page(struct page *page) @@ -1274,7 +1346,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, class = pool->size_class[class_idx]; off = (class->size * obj_idx) & ~PAGE_MASK; - area = &get_cpu_var(zs_map_area); + local_lock(&zs_map_area.lock); + area = this_cpu_ptr(&zs_map_area); area->vm_mm = mm; if (off + class->size <= PAGE_SIZE) { /* this object is contained entirely within a page */ @@ -1328,7 +1401,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) __zs_unmap_object(area, pages, off, class->size); } - put_cpu_var(zs_map_area); + local_unlock(&zs_map_area.lock); migrate_read_unlock(zspage); unpin_tag(handle); diff --git a/net/Kconfig b/net/Kconfig index c7392c449b25..d254b5143761 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -294,7 +294,7 @@ config CGROUP_NET_CLASSID config NET_RX_BUSY_POLL bool - default y + default y if !PREEMPT_RT config BQL bool diff --git a/net/core/dev.c b/net/core/dev.c index 1d66548b6fc0..1f7bf542899d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -225,14 +225,14 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex) static inline void rps_lock(struct softnet_data *sd) { #ifdef CONFIG_RPS - spin_lock(&sd->input_pkt_queue.lock); + raw_spin_lock(&sd->input_pkt_queue.raw_lock); #endif } static inline void rps_unlock(struct softnet_data *sd) { #ifdef CONFIG_RPS - spin_unlock(&sd->input_pkt_queue.lock); + raw_spin_unlock(&sd->input_pkt_queue.raw_lock); #endif } @@ -3125,6 +3125,7 @@ static void __netif_reschedule(struct Qdisc *q) sd->output_queue_tailp = &q->next_sched; raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_restore(flags); + preempt_check_resched_rt(); } void __netif_schedule(struct Qdisc *q) @@ -3187,6 +3188,7 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason) __this_cpu_write(softnet_data.completion_queue, skb); raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_restore(flags); + preempt_check_resched_rt(); } EXPORT_SYMBOL(__dev_kfree_skb_irq); @@ -3914,7 +3916,11 @@ no_lock_out: * This permits qdisc->running owner to get the lock more * often and dequeue packets faster. */ +#ifdef CONFIG_PREEMPT_RT + contended = true; +#else contended = qdisc_is_running(q); +#endif if (unlikely(contended)) spin_lock(&q->busylock); @@ -4736,6 +4742,7 @@ drop: rps_unlock(sd); local_irq_restore(flags); + preempt_check_resched_rt(); atomic_long_inc(&skb->dev->rx_dropped); kfree_skb(skb); @@ -4953,7 +4960,7 @@ static int netif_rx_internal(struct sk_buff *skb) struct rps_dev_flow voidflow, *rflow = &voidflow; int cpu; - preempt_disable(); + migrate_disable(); rcu_read_lock(); cpu = get_rps_cpu(skb->dev, skb, &rflow); @@ -4963,14 +4970,14 @@ static int netif_rx_internal(struct sk_buff *skb) ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail); rcu_read_unlock(); - preempt_enable(); + migrate_enable(); } else #endif { unsigned int qtail; - ret = enqueue_to_backlog(skb, get_cpu(), &qtail); - put_cpu(); + ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail); + put_cpu_light(); } return ret; } @@ -5009,11 +5016,9 @@ int netif_rx_ni(struct sk_buff *skb) trace_netif_rx_ni_entry(skb); - preempt_disable(); + local_bh_disable(); err = netif_rx_internal(skb); - if (local_softirq_pending()) - do_softirq(); - preempt_enable(); + local_bh_enable(); trace_netif_rx_ni_exit(err); return err; @@ -6461,12 +6466,14 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd) sd->rps_ipi_list = NULL; local_irq_enable(); + preempt_check_resched_rt(); /* Send pending IPI's to kick RPS processing on remote cpus. */ net_rps_send_ipi(remsd); } else #endif local_irq_enable(); + preempt_check_resched_rt(); } static bool sd_has_rps_ipi_waiting(struct softnet_data *sd) @@ -6544,6 +6551,7 @@ void __napi_schedule(struct napi_struct *n) local_irq_save(flags); ____napi_schedule(this_cpu_ptr(&softnet_data), n); local_irq_restore(flags); + preempt_check_resched_rt(); } EXPORT_SYMBOL(__napi_schedule); @@ -11355,6 +11363,7 @@ static int dev_cpu_dead(unsigned int oldcpu) raise_softirq_irqoff(NET_TX_SOFTIRQ); local_irq_enable(); + preempt_check_resched_rt(); #ifdef CONFIG_RPS remsd = oldsd->rps_ipi_list; @@ -11368,7 +11377,7 @@ static int dev_cpu_dead(unsigned int oldcpu) netif_rx_ni(skb); input_queue_head_incr(oldsd); } - while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) { + while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) { netif_rx_ni(skb); input_queue_head_incr(oldsd); } @@ -11684,7 +11693,7 @@ static int __init net_dev_init(void) INIT_WORK(flush, flush_backlog); - skb_queue_head_init(&sd->input_pkt_queue); + skb_queue_head_init_raw(&sd->input_pkt_queue); skb_queue_head_init(&sd->process_queue); #ifdef CONFIG_XFRM_OFFLOAD skb_queue_head_init(&sd->xfrm_backlog); diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c index 8e582e29a41e..e51f4854d8b2 100644 --- a/net/core/gen_estimator.c +++ b/net/core/gen_estimator.c @@ -42,7 +42,7 @@ struct net_rate_estimator { struct gnet_stats_basic_packed *bstats; spinlock_t *stats_lock; - seqcount_t *running; + net_seqlock_t *running; struct gnet_stats_basic_cpu __percpu *cpu_bstats; u8 ewma_log; u8 intvl_log; /* period : (250ms << intvl_log) */ @@ -125,7 +125,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu_bstats, struct net_rate_estimator __rcu **rate_est, spinlock_t *lock, - seqcount_t *running, + net_seqlock_t *running, struct nlattr *opt) { struct gnet_estimator *parm = nla_data(opt); @@ -226,7 +226,7 @@ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu_bstats, struct net_rate_estimator __rcu **rate_est, spinlock_t *lock, - seqcount_t *running, struct nlattr *opt) + net_seqlock_t *running, struct nlattr *opt) { return gen_new_estimator(bstats, cpu_bstats, rate_est, lock, running, opt); diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c index e491b083b348..ef432cea2e10 100644 --- a/net/core/gen_stats.c +++ b/net/core/gen_stats.c @@ -137,7 +137,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats, } void -__gnet_stats_copy_basic(const seqcount_t *running, +__gnet_stats_copy_basic(net_seqlock_t *running, struct gnet_stats_basic_packed *bstats, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b) @@ -150,15 +150,15 @@ __gnet_stats_copy_basic(const seqcount_t *running, } do { if (running) - seq = read_seqcount_begin(running); + seq = net_seq_begin(running); bstats->bytes = b->bytes; bstats->packets = b->packets; - } while (running && read_seqcount_retry(running, seq)); + } while (running && net_seq_retry(running, seq)); } EXPORT_SYMBOL(__gnet_stats_copy_basic); static int -___gnet_stats_copy_basic(const seqcount_t *running, +___gnet_stats_copy_basic(net_seqlock_t *running, struct gnet_dump *d, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b, @@ -204,7 +204,7 @@ ___gnet_stats_copy_basic(const seqcount_t *running, * if the room in the socket buffer was not sufficient. */ int -gnet_stats_copy_basic(const seqcount_t *running, +gnet_stats_copy_basic(net_seqlock_t *running, struct gnet_dump *d, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b) @@ -228,7 +228,7 @@ EXPORT_SYMBOL(gnet_stats_copy_basic); * if the room in the socket buffer was not sufficient. */ int -gnet_stats_copy_basic_hw(const seqcount_t *running, +gnet_stats_copy_basic_hw(net_seqlock_t *running, struct gnet_dump *d, struct gnet_stats_basic_cpu __percpu *cpu, struct gnet_stats_basic_packed *b) diff --git a/net/core/sock.c b/net/core/sock.c index 4a08ae6de578..daf6ef125318 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3183,12 +3183,11 @@ void lock_sock_nested(struct sock *sk, int subclass) if (sk->sk_lock.owned) __lock_sock(sk); sk->sk_lock.owned = 1; - spin_unlock(&sk->sk_lock.slock); + spin_unlock_bh(&sk->sk_lock.slock); /* * The sk_lock has mutex_lock() semantics here: */ mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_); - local_bh_enable(); } EXPORT_SYMBOL(lock_sock_nested); @@ -3237,13 +3236,12 @@ bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock) __lock_sock(sk); sk->sk_lock.owned = 1; - spin_unlock(&sk->sk_lock.slock); + spin_unlock_bh(&sk->sk_lock.slock); /* * The sk_lock has mutex_lock() semantics here: */ mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_); __acquire(&sk->sk_lock.slock); - local_bh_enable(); return true; } EXPORT_SYMBOL(lock_sock_fast); diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 75737267746f..e460c84b1f8e 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -637,7 +637,9 @@ int __inet_hash(struct sock *sk, struct sock *osk) int err = 0; if (sk->sk_state != TCP_LISTEN) { + local_bh_disable(); inet_ehash_nolisten(sk, osk, NULL); + local_bh_enable(); return 0; } WARN_ON(!sk_unhashed(sk)); @@ -669,11 +671,8 @@ int inet_hash(struct sock *sk) { int err = 0; - if (sk->sk_state != TCP_CLOSE) { - local_bh_disable(); + if (sk->sk_state != TCP_CLOSE) err = __inet_hash(sk, NULL); - local_bh_enable(); - } return err; } @@ -684,17 +683,20 @@ void inet_unhash(struct sock *sk) struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; struct inet_listen_hashbucket *ilb = NULL; spinlock_t *lock; + bool state_listen; if (sk_unhashed(sk)) return; if (sk->sk_state == TCP_LISTEN) { + state_listen = true; ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; - lock = &ilb->lock; + spin_lock(&ilb->lock); } else { + state_listen = false; lock = inet_ehash_lockp(hashinfo, sk->sk_hash); + spin_lock_bh(lock); } - spin_lock_bh(lock); if (sk_unhashed(sk)) goto unlock; @@ -707,7 +709,10 @@ void inet_unhash(struct sock *sk) __sk_nulls_del_node_init_rcu(sk); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); unlock: - spin_unlock_bh(lock); + if (state_listen) + spin_unlock(&ilb->lock); + else + spin_unlock_bh(lock); } EXPORT_SYMBOL_GPL(inet_unhash); diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 67c9114835c8..0a2e7f228391 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -333,11 +333,8 @@ int inet6_hash(struct sock *sk) { int err = 0; - if (sk->sk_state != TCP_CLOSE) { - local_bh_disable(); + if (sk->sk_state != TCP_CLOSE) err = __inet_hash(sk, NULL); - local_bh_enable(); - } return err; } diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 148edd0e71e3..21affae79e90 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1264,7 +1264,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, rcu_assign_pointer(sch->stab, stab); } if (tca[TCA_RATE]) { - seqcount_t *running; + net_seqlock_t *running; err = -EOPNOTSUPP; if (sch->flags & TCQ_F_MQROOT) { diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 66d2fbe9ef50..5d8c80ab16fc 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -606,7 +606,11 @@ struct Qdisc noop_qdisc = { .ops = &noop_qdisc_ops, .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock), .dev_queue = &noop_netdev_queue, +#ifdef CONFIG_PREEMPT_RT + .running = __SEQLOCK_UNLOCKED(noop_qdisc.running), +#else .running = SEQCNT_ZERO(noop_qdisc.running), +#endif .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock), .gso_skb = { .next = (struct sk_buff *)&noop_qdisc.gso_skb, @@ -916,9 +920,15 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, lockdep_set_class(&sch->seqlock, dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); +#ifdef CONFIG_PREEMPT_RT + seqlock_init(&sch->running); + lockdep_set_class(&sch->running.lock, + dev->qdisc_running_key ?: &qdisc_running_key); +#else seqcount_init(&sch->running); lockdep_set_class(&sch->running, dev->qdisc_running_key ?: &qdisc_running_key); +#endif sch->ops = ops; sch->flags = ops->static_flags; diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index cd5a2b186f0d..30190c03f4a2 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -441,7 +441,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) return; - cpu = get_cpu(); + cpu = get_cpu_light(); pool = svc_pool_for_cpu(xprt->xpt_server, cpu); atomic_long_inc(&pool->sp_stats.packets); @@ -465,7 +465,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) rqstp = NULL; out_unlock: rcu_read_unlock(); - put_cpu(); + put_cpu_light(); trace_svc_xprt_do_enqueue(xprt, rqstp); } EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue); diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c index 5a90aa527877..642d0748c169 100644 --- a/samples/kfifo/bytestream-example.c +++ b/samples/kfifo/bytestream-example.c @@ -22,10 +22,10 @@ #define PROC_FIFO "bytestream-fifo" /* lock for procfs read access */ -static DEFINE_MUTEX(read_lock); +static DEFINE_MUTEX(read_access); /* lock for procfs write access */ -static DEFINE_MUTEX(write_lock); +static DEFINE_MUTEX(write_access); /* * define DYNAMIC in this example for a dynamically allocated fifo. @@ -116,12 +116,12 @@ static ssize_t fifo_write(struct file *file, const char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&write_lock)) + if (mutex_lock_interruptible(&write_access)) return -ERESTARTSYS; ret = kfifo_from_user(&test, buf, count, &copied); - mutex_unlock(&write_lock); + mutex_unlock(&write_access); if (ret) return ret; @@ -134,12 +134,12 @@ static ssize_t fifo_read(struct file *file, char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&read_lock)) + if (mutex_lock_interruptible(&read_access)) return -ERESTARTSYS; ret = kfifo_to_user(&test, buf, count, &copied); - mutex_unlock(&read_lock); + mutex_unlock(&read_access); if (ret) return ret; diff --git a/samples/kfifo/inttype-example.c b/samples/kfifo/inttype-example.c index e5403d8c971a..c61482ba94f4 100644 --- a/samples/kfifo/inttype-example.c +++ b/samples/kfifo/inttype-example.c @@ -22,10 +22,10 @@ #define PROC_FIFO "int-fifo" /* lock for procfs read access */ -static DEFINE_MUTEX(read_lock); +static DEFINE_MUTEX(read_access); /* lock for procfs write access */ -static DEFINE_MUTEX(write_lock); +static DEFINE_MUTEX(write_access); /* * define DYNAMIC in this example for a dynamically allocated fifo. @@ -109,12 +109,12 @@ static ssize_t fifo_write(struct file *file, const char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&write_lock)) + if (mutex_lock_interruptible(&write_access)) return -ERESTARTSYS; ret = kfifo_from_user(&test, buf, count, &copied); - mutex_unlock(&write_lock); + mutex_unlock(&write_access); if (ret) return ret; @@ -127,12 +127,12 @@ static ssize_t fifo_read(struct file *file, char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&read_lock)) + if (mutex_lock_interruptible(&read_access)) return -ERESTARTSYS; ret = kfifo_to_user(&test, buf, count, &copied); - mutex_unlock(&read_lock); + mutex_unlock(&read_access); if (ret) return ret; diff --git a/samples/kfifo/record-example.c b/samples/kfifo/record-example.c index f64f3d62d6c2..e4087b2d3fc4 100644 --- a/samples/kfifo/record-example.c +++ b/samples/kfifo/record-example.c @@ -22,10 +22,10 @@ #define PROC_FIFO "record-fifo" /* lock for procfs read access */ -static DEFINE_MUTEX(read_lock); +static DEFINE_MUTEX(read_access); /* lock for procfs write access */ -static DEFINE_MUTEX(write_lock); +static DEFINE_MUTEX(write_access); /* * define DYNAMIC in this example for a dynamically allocated fifo. @@ -123,12 +123,12 @@ static ssize_t fifo_write(struct file *file, const char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&write_lock)) + if (mutex_lock_interruptible(&write_access)) return -ERESTARTSYS; ret = kfifo_from_user(&test, buf, count, &copied); - mutex_unlock(&write_lock); + mutex_unlock(&write_access); if (ret) return ret; @@ -141,12 +141,12 @@ static ssize_t fifo_read(struct file *file, char __user *buf, int ret; unsigned int copied; - if (mutex_lock_interruptible(&read_lock)) + if (mutex_lock_interruptible(&read_access)) return -ERESTARTSYS; ret = kfifo_to_user(&test, buf, count, &copied); - mutex_unlock(&read_lock); + mutex_unlock(&read_access); if (ret) return ret; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index b1694fa6f12b..726240013399 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -51,8 +51,10 @@ #define SMK_RECEIVING 1 #define SMK_SENDING 2 +#ifdef SMACK_IPV6_PORT_LABELING static DEFINE_MUTEX(smack_ipv6_lock); static LIST_HEAD(smk_ipv6_port_list); +#endif struct kmem_cache *smack_rule_cache; int smack_enabled; @@ -2603,7 +2605,6 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address) mutex_unlock(&smack_ipv6_lock); return; } -#endif /** * smk_ipv6_port_check - check Smack port access @@ -2666,6 +2667,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, return smk_ipv6_check(skp, object, address, act); } +#endif /** * smack_inode_setsecurity - set smack xattrs @@ -2852,8 +2854,9 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap, rc = smk_ipv6_check(ssp->smk_out, rsp, sip, SMK_CONNECTING); } - if (__is_defined(SMACK_IPV6_PORT_LABELING)) +#ifdef SMACK_IPV6_PORT_LABELING rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING); +#endif return rc; } diff --git a/sound/soc/mediatek/common/mtk-afe-fe-dai.c b/sound/soc/mediatek/common/mtk-afe-fe-dai.c index ab7bbd53bb01..1fd05b45d49e 100644 --- a/sound/soc/mediatek/common/mtk-afe-fe-dai.c +++ b/sound/soc/mediatek/common/mtk-afe-fe-dai.c @@ -288,7 +288,6 @@ const struct snd_soc_dai_ops mtk_afe_fe_ops = { }; EXPORT_SYMBOL_GPL(mtk_afe_fe_ops); -static DEFINE_MUTEX(irqs_lock); int mtk_dynamic_irq_acquire(struct mtk_base_afe *afe) { int i; |