add WEAK() for creating weak asm labels

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index 6c9873f..ff203dd 100644
--- a/include/linux/linkage.h
+++ b/include/linux/linkage.h
@@ -34,6 +34,12 @@
   name:
 #endif
 
+#ifndef WEAK
+#define WEAK(name)	   \
+	.weak name;	   \
+	name:
+#endif
+
 #define KPROBE_ENTRY(name) \
   .pushsection .kprobes.text, "ax"; \
   ENTRY(name)