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author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2017-09-29 17:15:36 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2017-09-29 19:39:44 +0200 |
commit | 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc (patch) | |
tree | a3cc45bbdcfb19bb4a46fd0713b34862da6c2657 /arch/x86/mm/tlb.c | |
parent | bc829ee36e0ec92383c9d9b88fe08f00d4d592f8 (diff) | |
download | linux-196bd485ee4f03ce4c690bfcf38138abfcd0a4bc.tar.gz |
x86/asm: Use register variable to get stack pointer value
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>
Diffstat (limited to 'arch/x86/mm/tlb.c')
-rw-r--r-- | arch/x86/mm/tlb.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 93fe97cce581..49d9778376d7 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -191,7 +191,7 @@ 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 index = pgd_index(current_stack_pointer()); + unsigned int index = pgd_index(current_stack_pointer); pgd_t *pgd = next->pgd + index; if (unlikely(pgd_none(*pgd))) |