From ea8f3b02a74a4e798e1fe5a8574ca6ccb829f353 Mon Sep 17 00:00:00 2001
From: Fenghua Yu <fenghua.yu@intel.com>
Date: Tue, 17 May 2011 15:29:17 -0700
Subject: [PATCH] --- yaml --- r: 245519 b: refs/heads/master c:
 057e05c1d6440117875f455e59da8691e08f65d5 h: refs/heads/master i:   245517:
 fa9c3c739e1a170607b8377587eb6c0373cfce95   245515:
 78df506fe8692fa1c5c10744be5cb9e06cd310b0   245511:
 c43269d9562664919ccc6ec5637260ddf2ad4450   245503:
 0ddf95c0b7b7fa09762f8d70f81afa7854636e93 v: v3

---
 [refs]                          |  2 +-
 trunk/arch/x86/lib/memmove_64.S | 29 ++++++++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 96eafaf21595..9ab68ad84461 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 101068c1f4a947ffa08f2782c78e40097300754d
+refs/heads/master: 057e05c1d6440117875f455e59da8691e08f65d5
diff --git a/trunk/arch/x86/lib/memmove_64.S b/trunk/arch/x86/lib/memmove_64.S
index 0ecb8433e5a8..d0ec9c2936d7 100644
--- a/trunk/arch/x86/lib/memmove_64.S
+++ b/trunk/arch/x86/lib/memmove_64.S
@@ -8,6 +8,7 @@
 #define _STRING_C
 #include <linux/linkage.h>
 #include <asm/dwarf2.h>
+#include <asm/cpufeature.h>
 
 #undef memmove
 
@@ -24,6 +25,7 @@
  */
 ENTRY(memmove)
 	CFI_STARTPROC
+
 	/* Handle more 32bytes in loop */
 	mov %rdi, %rax
 	cmp $0x20, %rdx
@@ -31,8 +33,13 @@ ENTRY(memmove)
 
 	/* Decide forward/backward copy mode */
 	cmp %rdi, %rsi
-	jb	2f
+	jge .Lmemmove_begin_forward
+	mov %rsi, %r8
+	add %rdx, %r8
+	cmp %rdi, %r8
+	jg 2f
 
+.Lmemmove_begin_forward:
 	/*
 	 * movsq instruction have many startup latency
 	 * so we handle small size by general register.
@@ -78,6 +85,8 @@ ENTRY(memmove)
 	rep movsq
 	movq %r11, (%r10)
 	jmp 13f
+.Lmemmove_end_forward:
+
 	/*
 	 * Handle data backward by movsq.
 	 */
@@ -194,4 +203,22 @@ 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"
+	.align 8
+	.quad .Lmemmove_begin_forward
+	.quad .Lmemmove_begin_forward_efs
+	.word X86_FEATURE_ERMS
+	.byte .Lmemmove_end_forward-.Lmemmove_begin_forward
+	.byte .Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs
+	.previous
 ENDPROC(memmove)