3 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86/include/asm/string_32.h b/arch/x86/include/asm/string_32.h
index 0e0e3ba827f7..c86f452256de 100644
--- a/arch/x86/include/asm/string_32.h
+++ b/arch/x86/include/asm/string_32.h
@@ -177,10 +177,18 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
  *      No 3D Now!
  */
 
+#ifndef CONFIG_KMEMCHECK
 #define memcpy(t, f, n)                         \
         (__builtin_constant_p((n))              \
          ? __constant_memcpy((t), (f), (n))     \
          : __memcpy((t), (f), (n)))
+#else
+/*
+ * kmemcheck becomes very happy if we use the REP instructions unconditionally,
+ * because it means that we know both memory operands in advance.
+ */
+#define memcpy(t, f, n) __memcpy((t), (f), (n))
+#endif
 
 #endif
 
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 2afe164bf1e6..19e2c468fc2c 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -27,6 +27,7 @@ static __always_inline void *__inline_memcpy(void *to, const void *from, size_t
    function. */
 
 #define __HAVE_ARCH_MEMCPY 1
+#ifndef CONFIG_KMEMCHECK
 #if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4
 extern void *memcpy(void *to, const void *from, size_t len);
 #else
@@ -42,6 +43,13 @@ extern void *__memcpy(void *to, const void *from, size_t len);
         __ret;                                                  \
 })
 #endif
+#else
+/*
+ * kmemcheck becomes very happy if we use the REP instructions unconditionally,
+ * because it means that we know both memory operands in advance.
+ */
+#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
+#endif
 
 #define __HAVE_ARCH_MEMSET
 void *memset(void *s, int c, size_t n);
diff --git a/arch/x86/include/asm/xor.h b/arch/x86/include/asm/xor.h
index 11b3bb86e17b..7fcf6f3dbcc3 100644
--- a/arch/x86/include/asm/xor.h
+++ b/arch/x86/include/asm/xor.h
@@ -1,5 +1,10 @@
+#ifdef CONFIG_KMEMCHECK
+/* kmemcheck doesn't handle MMX/SSE/SSE2 instructions */
+# include <asm-generic/xor.h>
+#else
 #ifdef CONFIG_X86_32
 # include "xor_32.h"
 #else
 # include "xor_64.h"
 #endif
+#endif