[PATCH] x86_64: make string func definition work as intended

In include/asm-x86_64/string.h there are such comments:

/* Use C out of line version for memcmp */
#define memcmp __builtin_memcmp
int memcmp(const void * cs,const void * ct,size_t count);

This would mean that if the compiler does not decide to use __builtin_memcmp,
it emits a call to memcmp to be satisfied by the C out-of-line version in
lib/string.c.  What happens is that after preprocessing, in lib/string.i you
may find the definition of "__builtin_strcmp".

Actually, by accident, in the object you will find the definition of strcmp
and such (maybe a trick intended to redirect calls to __builtin_memcmp to the
default memcmp when the definition is not expanded); however, this particular
case is not a documented feature as far as I can see.

Also, the EXPORT_SYMBOL does not work, so it's duplicated in the arch.

I simply added some #undef to lib/string.c and removed the (now duplicated)
exports in x86-64 and UML/x86_64 subarchs (the second ones are introduced by
another patch I just posted for -mm).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/string.c b/lib/string.c
index 4bb93ad23c6..5c8b55af0df 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -65,6 +65,7 @@ EXPORT_SYMBOL(strnicmp);
  * @dest: Where to copy the string to
  * @src: Where to copy the string from
  */
+#undef strcpy
 char * strcpy(char * dest,const char *src)
 {
 	char *tmp = dest;
@@ -132,6 +133,7 @@ EXPORT_SYMBOL(strlcpy);
  * @dest: The string to be appended to
  * @src: The string to append to it
  */
+#undef strcat
 char * strcat(char * dest, const char * src)
 {
 	char *tmp = dest;
@@ -209,6 +211,7 @@ EXPORT_SYMBOL(strlcat);
  * @cs: One string
  * @ct: Another string
  */
+#undef strcmp
 int strcmp(const char * cs,const char * ct)
 {
 	register signed char __res;
@@ -514,6 +517,7 @@ EXPORT_SYMBOL(memmove);
  * @ct: Another area of memory
  * @count: The size of the area.
  */
+#undef memcmp
 int memcmp(const void * cs,const void * ct,size_t count)
 {
 	const unsigned char *su1, *su2;