x86: Import glibc memcpy implementation

Taken from glibc version 2.14.90

--
Changes for v2:
 - None

diff --git a/arch/x86/include/asm/string.h b/arch/x86/include/asm/string.h
index 3aa6c1131b21cd3d192a454414c8c9ccb61dd75f..0ad612f6273af9be2e0137681076ab6f1bb4bef9 100644 (file)
--- a/arch/x86/include/asm/string.h
+++ b/arch/x86/include/asm/string.h
@@ -14,7 +14,7 @@ extern char * strrchr(const char * s, int c);
 #undef __HAVE_ARCH_STRCHR
 extern char * strchr(const char * s, int c);
 
-#undef __HAVE_ARCH_MEMCPY
+#define __HAVE_ARCH_MEMCPY
 extern void * memcpy(void *, const void *, __kernel_size_t);
 
 #undef __HAVE_ARCH_MEMMOVE

diff --git a/arch/x86/lib/string.c b/arch/x86/lib/string.c
index f2ea7e4e338608799d6f7debe93ed8ab0e994512..1fde81b8b760f3b6a3b82eb7b4d64966db984ba1 100644 (file)
--- a/arch/x86/lib/string.c
+++ b/arch/x86/lib/string.c
@@ -85,3 +85,64 @@ void *memset(void *dstpp, int c, size_t len)
 
        return dstpp;
 }
+
+#define        OP_T_THRES      8
+#define OPSIZ  (sizeof(op_t))
+
+#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes)                            \
+do {                                                                     \
+       int __d0;                                                         \
+       asm volatile(                                                     \
+               /* Clear the direction flag, so copying goes forward.  */ \
+               "cld\n"                                                   \
+               /* Copy bytes.  */                                        \
+               "rep\n"                                                   \
+               "movsb" :                                                 \
+               "=D" (dst_bp), "=S" (src_bp), "=c" (__d0) :               \
+               "0" (dst_bp), "1" (src_bp), "2" (nbytes) :                \
+               "memory");                                                \
+} while (0)
+
+#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes)               \
+do {                                                                     \
+       int __d0;                                                         \
+       asm volatile(                                                     \
+               /* Clear the direction flag, so copying goes forward.  */ \
+               "cld\n"                                                   \
+               /* Copy longwords.  */                                    \
+               "rep\n"                                                   \
+               "movsl" :                                                 \
+               "=D" (dst_bp), "=S" (src_bp), "=c" (__d0) :               \
+               "0" (dst_bp), "1" (src_bp), "2" ((nbytes) / 4) :          \
+               "memory");                                                \
+       (nbytes_left) = (nbytes) % 4;                                     \
+} while (0)
+
+void *memcpy(void *dstpp, const void *srcpp, size_t len)
+{
+       unsigned long int dstp = (long int)dstpp;
+       unsigned long int srcp = (long int)srcpp;
+
+       /* Copy from the beginning to the end.  */
+
+       /* If there not too few bytes to copy, use word copy.  */
+       if (len >= OP_T_THRES) {
+               /* Copy just a few bytes to make DSTP aligned.  */
+               len -= (-dstp) % OPSIZ;
+               BYTE_COPY_FWD(dstp, srcp, (-dstp) % OPSIZ);
+
+               /* Copy from SRCP to DSTP taking advantage of the known
+                * alignment of DSTP.  Number of bytes remaining is put
+                * in the third argument, i.e. in LEN.  This number may
+                * vary from machine to machine.
+                */
+               WORD_COPY_FWD(dstp, srcp, len, len);
+
+               /* Fall out and copy the tail.  */
+       }
+
+       /* There are just a few bytes to copy. Use byte memory operations. */
+       BYTE_COPY_FWD(dstp, srcp, len);
+
+       return dstpp;
+}