diff -Napur -X /home/jbarnes/dontdiff linux-2.6.20/arch/x86_64/lib/memcpy.S linux-2.6.20-no-rmb/arch/x86_64/lib/memcpy.S
--- linux-2.6.20/arch/x86_64/lib/memcpy.S	2007-02-04 10:44:54.000000000 -0800
+++ linux-2.6.20-no-rmb/arch/x86_64/lib/memcpy.S	2007-04-19 12:01:34.000000000 -0700
@@ -26,6 +26,7 @@ memcpy_c:
 	rep movsq
 	movl %edx,%ecx
 	rep movsb
+	sfence
 	ret
 	CFI_ENDPROC
 ENDPROC(memcpy_c)
diff -Napur -X /home/jbarnes/dontdiff linux-2.6.20/arch/x86_64/lib/memset.S linux-2.6.20-no-rmb/arch/x86_64/lib/memset.S
--- linux-2.6.20/arch/x86_64/lib/memset.S	2007-02-04 10:44:54.000000000 -0800
+++ linux-2.6.20-no-rmb/arch/x86_64/lib/memset.S	2007-04-19 12:02:04.000000000 -0700
@@ -28,6 +28,7 @@ memset_c:
 	movl %r8d,%ecx
 	rep stosb
 	movq %r9,%rax
+	sfence
 	ret
 	CFI_ENDPROC
 ENDPROC(memset_c)
diff -Napur -X /home/jbarnes/dontdiff linux-2.6.20/include/asm-i386/system.h linux-2.6.20-no-rmb/include/asm-i386/system.h
--- linux-2.6.20/include/asm-i386/system.h	2007-02-04 10:44:54.000000000 -0800
+++ linux-2.6.20-no-rmb/include/asm-i386/system.h	2007-04-19 11:19:26.000000000 -0700
@@ -421,7 +421,7 @@ static inline unsigned long long __cmpxc
  */
 
 #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
-#define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
+#define rmb() asm volatile("" ::: "memory")
 
 /**
  * read_barrier_depends - Flush all pending reads that subsequents reads