asm: Move builtin_memcpy helper into asm/string.h

There will be a couple of more builtin helpers needed
in pie code soon. Thus to unify approach do

 - rename asm/memcpy_64.h to asm/string.h

 - introduce include/asm-generic/string.h file
   where all helpers are implemented if optimized
   variant is not  yet provided
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/arm/include/asm/string.h

+#ifndef __CR_ASM_STRING_H__
+#define __CR_ASM_STRING_H__
+
+#include "compiler.h"
+#include "asm-generic/string.h"
+
+#endif /* __CR_ASM_STRING_H__ */

arch/arm/restorer.c

@@ -2,7 +2,7 @@
 
 #include "restorer.h"
 #include "asm/restorer.h"
-#include "asm/memcpy_64.h"
+#include "asm/string.h"
 
 #include "syscall.h"
 #include "log.h"

arch/x86/include/asm/memcpy_64.h → arch/x86/include/asm/string.h

-#ifndef __CR_MEMCPY_64_H__
-#define __CR_MEMCPY_64_H__
+#ifndef __CR_ASM_STRING_H__
+#define __CR_ASM_STRING_H__
+
+#define HAS_BUILTIN_MEMCPY
 
 #include "compiler.h"
-#include "asm/types.h"
+#include "asm-generic/string.h"
 
 static always_inline void *builtin_memcpy(void *to, const void *from, unsigned int n)
 {
@@ -19,4 +21,4 @@ static always_inline void *builtin_memcpy(void *to, const void *from, unsigned i
 	return to;
 }
 
-#endif /* __CR_MEMCPY_64_H__ */
+#endif /* __CR_ASM_STRING_H__ */

arch/arm/include/asm/memcpy_64.h → include/asm-generic/string.h

-#ifndef __MEMCPY_ARM_H__
-#define __MEMCPY_ARM_H__
+#ifndef __CR_ASM_GENERIC_STRING_H__
+#define __CR_ASM_GENERIC_STRING_H__
 
 #include "compiler.h"
-#include "types.h"
 
+#ifndef HAS_BUILTIN_MEMCPY
 static always_inline void *builtin_memcpy(void *to, const void *from, unsigned int n)
 {
 	int i;
@@ -16,5 +16,6 @@ static always_inline void *builtin_memcpy(void *to, const void *from, unsigned i
 
 	return to;
 }
-
 #endif
+
+#endif /* __CR_ASM_GENERIC_STRING_H__ */

pie/util-net.c

@@ -4,7 +4,7 @@
 #include <errno.h>
 
 #include "compiler.h"
-#include "asm/memcpy_64.h"
+#include "asm/string.h"
 #include "asm/types.h"
 #include "syscall.h"