[tip:x86/cpufeature] x86, cpufeature: Add CPU feature bit for enhanced REP MOVSB/STOSB

From: tip-bot for Fenghua Yu
Date: Tue May 17 2011 - 19:13:36 EST

Commit-ID: 724a92ee45c04cb9d82884a856b03b1e594d9de1
Gitweb: http://git.kernel.org/tip/724a92ee45c04cb9d82884a856b03b1e594d9de1
Author: Fenghua Yu <fenghua.yu@xxxxxxxxx>
AuthorDate: Tue, 17 May 2011 15:29:10 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 17 May 2011 14:56:36 -0700

x86, cpufeature: Add CPU feature bit for enhanced REP MOVSB/STOSB

Intel processors are adding enhancements to REP MOVSB/STOSB and the use of
REP MOVSB/STOSB for optimal memcpy/memset or similar functions is recommended.
Enhancement availability is indicated by CPUID.7.0.EBX[9] (Enhanced REP MOVSB/

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1305671358-14478-2-git-send-email-fenghua.yu@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
arch/x86/include/asm/cpufeature.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 91f3e087..7f2f7b1 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -195,6 +195,7 @@

/* Intel-defined CPU features, CPUID level 0x00000007:0 (ebx), word 9 */
#define X86_FEATURE_FSGSBASE (9*32+ 0) /* {RD/WR}{FS/GS}BASE instructions*/
+#define X86_FEATURE_ERMS (9*32+ 9) /* Enhanced REP MOVSB/STOSB */

#if defined(__KERNEL__) && !defined(__ASSEMBLY__)

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