Messages in this thread | | | Date | Fri, 29 Sep 2017 10:38:28 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH] x86: use register variable to get stack pointer value |
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On Fri, Sep 29, 2017 at 05:15:36PM +0300, Andrey Ryabinin wrote: > 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 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 removed function. > > Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
-- Josh
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