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x86/lib/memmove_64.S: Convert memmove() to ALTERNATIVE macro

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Make it execute the ERMS version if support is present and we're in the
forward memmove() part and remove the unfolded alternatives section
definition.

Signed-off-by: Borislav Petkov <bp@suse.de>
This commit is contained in:
Borislav Petkov 2015-02-04 09:11:17 +01:00
parent 84d95ad4cb
commit a77600cd03
1 changed files with 2 additions and 17 deletions
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19
arch/x86/lib/memmove_64.S
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@ -5,7 +5,6 @@
* This assembly file is re-written from memmove_64.c file.
* - Copyright 2011 Fenghua Yu <fenghua.yu@intel.com>
*/
#define _STRING_C
#include <linux/linkage.h>
#include <asm/dwarf2.h>
#include <asm/cpufeature.h>
@ -44,6 +43,8 @@ ENTRY(__memmove)
jg 2f
.Lmemmove_begin_forward:
ALTERNATIVE "", "movq %rdx, %rcx; rep movsb; retq", X86_FEATURE_ERMS
/*
* movsq instruction have many startup latency
* so we handle small size by general register.
@ -207,21 +208,5 @@ ENTRY(__memmove)
13:
retq
CFI_ENDPROC
.section .altinstr_replacement,"ax"
.Lmemmove_begin_forward_efs:
/* Forward moving data. */
movq %rdx, %rcx
rep movsb
retq
.Lmemmove_end_forward_efs:
.previous
.section .altinstructions,"a"
altinstruction_entry .Lmemmove_begin_forward, \
.Lmemmove_begin_forward_efs,X86_FEATURE_ERMS, \
.Lmemmove_end_forward-.Lmemmove_begin_forward, \
.Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs,0
.previous
ENDPROC(__memmove)
ENDPROC(memmove)