x86: re-introduce support for ERMS copies for user space accesses

[sfrench/cifs-2.6.git] / arch / x86 / lib / copy_user_64.S

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 4fc5c2de2de467c689ddf91eb1684eeb00aeb9db..01c5de4c279b8fe8cf0fcd914f4cb4ec31945bc8 100644 (file)
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -7,6 +7,8 @@
  */
 
 #include <linux/linkage.h>
+#include <asm/cpufeatures.h>
+#include <asm/alternative.h>
 #include <asm/asm.h>
 #include <asm/export.h>
 
@@ -29,7 +31,7 @@
  */
 SYM_FUNC_START(rep_movs_alternative)
        cmpq $64,%rcx
-       jae .Lunrolled
+       jae .Llarge
 
        cmp $8,%ecx
        jae .Lword
@@ -65,6 +67,12 @@ SYM_FUNC_START(rep_movs_alternative)
        _ASM_EXTABLE_UA( 2b, .Lcopy_user_tail)
        _ASM_EXTABLE_UA( 3b, .Lcopy_user_tail)
 
+.Llarge:
+0:     ALTERNATIVE "jmp .Lunrolled", "rep movsb", X86_FEATURE_ERMS
+1:     RET
+
+        _ASM_EXTABLE_UA( 0b, 1b)
+
        .p2align 4
 .Lunrolled:
 10:    movq (%rsi),%r8