diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0065-x86-asm-Use-register-variable-to-get-stack-pointer-v.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0065-x86-asm-Use-register-variable-to-get-stack-pointer-v.patch | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0065-x86-asm-Use-register-variable-to-get-stack-pointer-v.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0065-x86-asm-Use-register-variable-to-get-stack-pointer-v.patch new file mode 100644 index 00000000..d6be8601 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0065-x86-asm-Use-register-variable-to-get-stack-pointer-v.patch @@ -0,0 +1,150 @@ +From e162de37c3c74f0615f030cb30571a6adad3a6c7 Mon Sep 17 00:00:00 2001 +From: Andrey Ryabinin <aryabinin@virtuozzo.com> +Date: Fri, 29 Sep 2017 17:15:36 +0300 +Subject: [PATCH 065/103] x86/asm: Use register variable to get stack pointer + value + +commit 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc upstream. + +Currently we use current_stack_pointer() function to get the value +of the stack pointer register. Since commit: + + f5caf621ee35 ("x86/asm: Fix inline asm call constraints for Clang") + +... we have a stack register variable declared. It can be used instead of +current_stack_pointer() function which allows to optimize away some +excessive "mov %rsp, %<dst>" instructions: + + -mov %rsp,%rdx + -sub %rdx,%rax + -cmp $0x3fff,%rax + -ja ffffffff810722fd <ist_begin_non_atomic+0x2d> + + +sub %rsp,%rax + +cmp $0x3fff,%rax + +ja ffffffff810722fa <ist_begin_non_atomic+0x2a> + +Remove current_stack_pointer(), rename __asm_call_sp to current_stack_pointer +and use it instead of the removed function. + +Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> +Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> +Cc: Andy Lutomirski <luto@kernel.org> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Thomas Gleixner <tglx@linutronix.de> +Link: http://lkml.kernel.org/r/20170929141537.29167-1-aryabinin@virtuozzo.com +Signed-off-by: Ingo Molnar <mingo@kernel.org> +[dwmw2: We want ASM_CALL_CONSTRAINT for retpoline] +Signed-off-by: David Woodhouse <dwmw@amazon.co.ku> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/include/asm/asm.h | 11 +++++++++++ + arch/x86/include/asm/thread_info.h | 11 ----------- + arch/x86/kernel/irq_32.c | 6 +++--- + arch/x86/kernel/traps.c | 2 +- + arch/x86/mm/tlb.c | 2 +- + 5 files changed, 16 insertions(+), 16 deletions(-) + +diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h +index 7acb51c..0052352 100644 +--- a/arch/x86/include/asm/asm.h ++++ b/arch/x86/include/asm/asm.h +@@ -125,4 +125,15 @@ + /* For C file, we already have NOKPROBE_SYMBOL macro */ + #endif + ++#ifndef __ASSEMBLY__ ++/* ++ * This output constraint should be used for any inline asm which has a "call" ++ * instruction. Otherwise the asm may be inserted before the frame pointer ++ * gets set up by the containing function. If you forget to do this, objtool ++ * may print a "call without frame pointer save/setup" warning. ++ */ ++register unsigned long current_stack_pointer asm(_ASM_SP); ++#define ASM_CALL_CONSTRAINT "+r" (current_stack_pointer) ++#endif ++ + #endif /* _ASM_X86_ASM_H */ +diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h +index ad6f5eb0..bdf9c4c 100644 +--- a/arch/x86/include/asm/thread_info.h ++++ b/arch/x86/include/asm/thread_info.h +@@ -152,17 +152,6 @@ struct thread_info { + */ + #ifndef __ASSEMBLY__ + +-static inline unsigned long current_stack_pointer(void) +-{ +- unsigned long sp; +-#ifdef CONFIG_X86_64 +- asm("mov %%rsp,%0" : "=g" (sp)); +-#else +- asm("mov %%esp,%0" : "=g" (sp)); +-#endif +- return sp; +-} +- + /* + * Walks up the stack frames to make sure that the specified object is + * entirely contained by a single stack frame. +diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c +index 1f38d9a..d4eb450 100644 +--- a/arch/x86/kernel/irq_32.c ++++ b/arch/x86/kernel/irq_32.c +@@ -64,7 +64,7 @@ static void call_on_stack(void *func, void *stack) + + static inline void *current_stack(void) + { +- return (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1)); ++ return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1)); + } + + static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc) +@@ -88,7 +88,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc) + + /* Save the next esp at the bottom of the stack */ + prev_esp = (u32 *)irqstk; +- *prev_esp = current_stack_pointer(); ++ *prev_esp = current_stack_pointer; + + if (unlikely(overflow)) + call_on_stack(print_stack_overflow, isp); +@@ -139,7 +139,7 @@ void do_softirq_own_stack(void) + + /* Push the previous esp onto the stack */ + prev_esp = (u32 *)irqstk; +- *prev_esp = current_stack_pointer(); ++ *prev_esp = current_stack_pointer; + + call_on_stack(__do_softirq, isp); + } +diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c +index bd4e3d4..322f433 100644 +--- a/arch/x86/kernel/traps.c ++++ b/arch/x86/kernel/traps.c +@@ -153,7 +153,7 @@ void ist_begin_non_atomic(struct pt_regs *regs) + * from double_fault. + */ + BUG_ON((unsigned long)(current_top_of_stack() - +- current_stack_pointer()) >= THREAD_SIZE); ++ current_stack_pointer) >= THREAD_SIZE); + + preempt_enable_no_resched(); + } +diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c +index e81f8bb..0cf44ac 100644 +--- a/arch/x86/mm/tlb.c ++++ b/arch/x86/mm/tlb.c +@@ -114,7 +114,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, + * mapped in the new pgd, we'll double-fault. Forcibly + * map it. + */ +- unsigned int stack_pgd_index = pgd_index(current_stack_pointer()); ++ unsigned int stack_pgd_index = pgd_index(current_stack_pointer); + + pgd_t *pgd = next->pgd + stack_pgd_index; + +-- +2.7.4 + |