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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 20:39:44 +0300 |
commit | 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc (patch) | |
tree | a3cc45bbdcfb19bb4a46fd0713b34862da6c2657 /Kconfig | |
parent | bc829ee36e0ec92383c9d9b88fe08f00d4d592f8 (diff) | |
download | linux-196bd485ee4f03ce4c690bfcf38138abfcd0a4bc.tar.xz |
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 'Kconfig')
0 files changed, 0 insertions, 0 deletions