2 files changed, 41 insertions, 1 deletions

diff --git a/arch/s390/include/asm/string.h b/arch/s390/include/asm/string.h
index 8662f5c8e17f..15a3c005c274 100644
--- a/arch/s390/include/asm/string.h
+++ b/arch/s390/include/asm/string.h
@@ -14,6 +14,7 @@
 #define __HAVE_ARCH_MEMCHR      /* inline & arch function */
 #define __HAVE_ARCH_MEMCMP      /* arch function */
 #define __HAVE_ARCH_MEMCPY      /* gcc builtin & arch function */
+#define __HAVE_ARCH_MEMMOVE     /* gcc builtin & arch function */
 #define __HAVE_ARCH_MEMSCAN     /* inline & arch function */
 #define __HAVE_ARCH_MEMSET      /* gcc builtin & arch function */
 #define __HAVE_ARCH_STRCAT      /* inline & arch function */
@@ -32,6 +33,7 @@
 extern int memcmp(const void *, const void *, size_t);
 extern void *memcpy(void *, const void *, size_t);
 extern void *memset(void *, int, size_t);
+extern void *memmove(void *, const void *, size_t);
 extern int strcmp(const char *,const char *);
 extern size_t strlcat(char *, const char *, size_t);
 extern size_t strlcpy(char *, const char *, size_t);
@@ -40,7 +42,6 @@ extern char *strncpy(char *, const char *, size_t);
 extern char *strrchr(const char *, int);
 extern char *strstr(const char *, const char *);
 
-#undef __HAVE_ARCH_MEMMOVE
 #undef __HAVE_ARCH_STRCHR
 #undef __HAVE_ARCH_STRNCHR
 #undef __HAVE_ARCH_STRNCMP
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
index be9fa65bfac4..7422a706f310 100644
--- a/arch/s390/lib/mem.S
+++ b/arch/s390/lib/mem.S
@@ -8,6 +8,45 @@
 #include <asm/export.h>
 
 /*
+ * void *memmove(void *dest, const void *src, size_t n)
+ */
+ENTRY(memmove)
+        ltgr    %r4,%r4
+        lgr     %r1,%r2
+        bzr     %r14
+        clgr    %r2,%r3
+        jnh     .Lmemmove_forward
+        la      %r5,0(%r4,%r3)
+        clgr    %r2,%r5
+        jl      .Lmemmove_reverse
+.Lmemmove_forward:
+        aghi    %r4,-1
+        srlg    %r0,%r4,8
+        ltgr    %r0,%r0
+        jz      .Lmemmove_rest
+.Lmemmove_loop:
+        mvc     0(256,%r1),0(%r3)
+        la      %r1,256(%r1)
+        la      %r3,256(%r3)
+        brctg   %r0,.Lmemmove_loop
+.Lmemmove_rest:
+        larl    %r5,.Lmemmove_mvc
+        ex      %r4,0(%r5)
+        br      %r14
+.Lmemmove_reverse:
+        aghi    %r4,-1
+.Lmemmove_reverse_loop:
+        ic      %r0,0(%r4,%r3)
+        stc     %r0,0(%r4,%r1)
+        brctg   %r4,.Lmemmove_reverse_loop
+        ic      %r0,0(%r4,%r3)
+        stc     %r0,0(%r4,%r1)
+        br      %r14
+.Lmemmove_mvc:
+        mvc     0(1,%r1),0(%r3)
+EXPORT_SYMBOL(memmove)
+
+/*
  * memset implementation
  *
  * This code corresponds to the C construct below. We do distinguish