diff --git a/xen/include/xen/prefetch.h b/xen/include/xen/prefetch.h
index 8d7d3ffeb4..ba7399828e 100644
--- a/xen/include/xen/prefetch.h
+++ b/xen/include/xen/prefetch.h
@@ -28,24 +28,17 @@
 	prefetchw(x)	- prefetches the cacheline at "x" for write
 	spin_lock_prefetch(x) - prefectches the spinlock *x for taking
 	
-	there is also PREFETCH_STRIDE which is the architecure-prefered 
+	there is also PREFETCH_STRIDE which is the architecture-preferred
 	"lookahead" size for prefetching streamed operations.
 	
 */
 
-/*
- *	These cannot be do{}while(0) macros. See the mental gymnastics in
- *	the loop macro.
- */
- 
 #ifndef ARCH_HAS_PREFETCH
-#define ARCH_HAS_PREFETCH
-static inline void prefetch(const void *x) {;}
+#define prefetch(x) __builtin_prefetch(x)
 #endif
 
 #ifndef ARCH_HAS_PREFETCHW
-#define ARCH_HAS_PREFETCHW
-static inline void prefetchw(const void *x) {;}
+#define prefetchw(x) __builtin_prefetch(x,1)
 #endif
 
 #ifndef ARCH_HAS_SPINLOCK_PREFETCH