diff options
Diffstat (limited to 'features/rt/arm-Add-support-for-lazy-preemption.patch')
| -rw-r--r-- | features/rt/arm-Add-support-for-lazy-preemption.patch | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/features/rt/arm-Add-support-for-lazy-preemption.patch b/features/rt/arm-Add-support-for-lazy-preemption.patch new file mode 100644 index 00000000..b6e2718c --- /dev/null +++ b/features/rt/arm-Add-support-for-lazy-preemption.patch @@ -0,0 +1,136 @@ +From 71f7a0c901c01218f119d2e16cb22e1069a61900 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Wed, 31 Oct 2012 12:04:11 +0100 +Subject: [PATCH 166/191] arm: Add support for lazy preemption + +Implement the arm pieces for lazy preempt. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +--- + arch/arm/Kconfig | 1 + + arch/arm/include/asm/thread_info.h | 6 +++++- + arch/arm/kernel/asm-offsets.c | 1 + + arch/arm/kernel/entry-armv.S | 19 ++++++++++++++++--- + arch/arm/kernel/signal.c | 3 ++- + 5 files changed, 25 insertions(+), 5 deletions(-) + +diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig +index 5da96f5df48f..5179eb3a35d5 100644 +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -107,6 +107,7 @@ 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 +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 be8050b0c3df..884e40a525ce 100644 +--- a/arch/arm/kernel/asm-offsets.c ++++ b/arch/arm/kernel/asm-offsets.c +@@ -42,6 +42,7 @@ 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))) +-- +2.19.1 + |