diff -Nur xen-unstable-0301.orig/tools/blktap/blktaplib.h xen-unstable-0301-test/tools/blktap/blktaplib.h
--- xen-unstable-0301.orig/tools/blktap/blktaplib.h	2005-03-01 06:54:49.000000000 -0600
+++ xen-unstable-0301-test/tools/blktap/blktaplib.h	2005-03-01 16:24:25.780124280 -0600
@@ -10,22 +10,6 @@
 
 #include <stdint.h>
 
-typedef uint8_t            u8;
-typedef uint16_t           u16;
-typedef uint32_t           u32;
-typedef uint64_t           u64;
-typedef int8_t             s8;
-typedef int16_t            s16;
-typedef int32_t            s32;
-typedef int64_t            s64;
-                                                                                
-#if defined(__i386__)
-#define rmb() __asm__ __volatile__ ( "lock; addl $0,0(%%esp)" : : : "memory" )
-#define wmb() __asm__ __volatile__ ( "" : : : "memory" )
-#else
-#error "Define barriers"
-#endif
-    
 #include <sys/user.h>
 #include <xen/xen.h>
 #include <xen/io/blkif.h>
diff -Nur xen-unstable-0301.orig/tools/libxc/xc.h xen-unstable-0301-test/tools/libxc/xc.h
--- xen-unstable-0301.orig/tools/libxc/xc.h	2005-03-01 06:54:49.000000000 -0600
+++ xen-unstable-0301-test/tools/libxc/xc.h	2005-03-01 16:05:53.248254832 -0600
@@ -25,6 +25,21 @@
 #include <xen/event_channel.h>
 #include <xen/sched_ctl.h>
 
+
+/*\
+ *  DEFINITIONS FOR CPU BARRIERS
+\*/ 
+#if defined(__i386__)
+#define rmb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)" : : : "memory")
+#define wmb() __asm__ __volatile__ ("" : : : "memory")
+#elif defined(__x86_64__)
+#define mb()     asm volatile("mfence":::"memory")
+#define rmb()    asm volatile("lfence":::"memory")
+#define wmb()    asm volatile( "" :::"memory")
+#else
+#error "Define barriers"
+#endif
+
 /*\
  *  INITIALIZATION FUNCTIONS
 \*/ 
diff -Nur xen-unstable-0301.orig/tools/python/xen/lowlevel/xu/xu.c xen-unstable-0301-test/tools/python/xen/lowlevel/xu/xu.c
--- xen-unstable-0301.orig/tools/python/xen/lowlevel/xu/xu.c	2005-03-01 06:54:49.000000000 -0600
+++ xen-unstable-0301-test/tools/python/xen/lowlevel/xu/xu.c	2005-03-01 16:01:13.083846296 -0600
@@ -49,14 +49,6 @@
 /* Size of a machine page frame. */
 #define PAGE_SIZE 4096
 
-#if defined(__i386__)
-#define rmb() __asm__ __volatile__ ( "lock; addl $0,0(%%esp)" : : : "memory" )
-#define wmb() __asm__ __volatile__ ( "" : : : "memory" )
-#else
-#error "Define barriers"
-#endif
-
-
 /* Set the close-on-exec flag on a file descriptor.  Doesn't currently bother
  * to check for errors. */
 /*
diff -Nur xen-unstable-0301.orig/tools/xcs/xcs.h xen-unstable-0301-test/tools/xcs/xcs.h
--- xen-unstable-0301.orig/tools/xcs/xcs.h	2005-03-01 06:54:49.000000000 -0600
+++ xen-unstable-0301-test/tools/xcs/xcs.h	2005-03-01 16:02:22.707261928 -0600
@@ -39,13 +39,6 @@
 /* Size of a machine page frame. */
 #define PAGE_SIZE 4096
 
-#if defined(__i386__)
-#define rmb() __asm__ __volatile__ ( "lock; addl $0,0(%%esp)" : : : "memory" )
-#define wmb() __asm__ __volatile__ ( "" : : : "memory" )
-#else
-#error "Define barriers"
-#endif
-
 #ifndef timersub /* XOPEN and __BSD don't cooperate well... */
 #define timersub(a, b, result)                                                \
   do {                                                                        \