diff -ur src.old/sys/amd64/include/atomic.h src/sys/amd64/include/atomic.h
--- src.old/sys/amd64/include/atomic.h	Sat Apr 29 18:55:51 2006
+++ src/sys/amd64/include/atomic.h	Sat Apr 29 19:57:47 2006
@@ -203,15 +203,8 @@
 static __inline u_##TYPE				\
 atomic_load_acq_##TYPE(volatile u_##TYPE *p)		\
 {							\
-	u_##TYPE res;					\
-							\
-	__asm __volatile(__XSTRING(MPLOCKED) LOP	\
-	: "=a" (res),			/* 0 (result) */\
-	  "=m" (*p)			/* 1 */		\
-	: "m" (*p)			/* 2 */		\
-	: "memory");				 	\
-							\
-	return (res);					\
+	__asm__ __volatile("lfence");			\
+	return (*p);					\
 }							\
 							\
 /*							\
@@ -220,10 +213,8 @@
 static __inline void					\
 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
 {							\
-	__asm __volatile(SOP				\
-	: "=m" (*p),			/* 0 */		\
-	  "+r" (v)			/* 1 */		\
-	: "m" (*p));			/* 2 */		\
+	*p = v;						\
+	__asm__ __volatile("lfence");			\
 }							\
 struct __hack