From: Keir Fraser <keir@xen.org>
Date: Sat, 21 Jan 2012 17:14:37 +0000 (+0000)
Subject: libxc: Update rmb/wmb for x86.
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks:///%22http:/www.example.com/cgi/%22https:/%22bookmarks:/?a=commitdiff_plain;h=8d3f757328e1580a8363597543b8e36ecc8837de;p=xen.git

libxc: Update rmb/wmb for x86.

Only the compiler needs to see the barriers; not the CPU.

Signed-off-by: Keir Fraser <keir@xen.org>
---

diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 8b347697cc..37b0fd6f23 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -69,14 +69,16 @@
  *  DEFINITIONS FOR CPU BARRIERS
  */
 
+#define xen_barrier() asm volatile ( "" : : : "memory")
+
 #if defined(__i386__)
 #define xen_mb()  asm volatile ( "lock; addl $0,0(%%esp)" : : : "memory" )
-#define xen_rmb() asm volatile ( "lock; addl $0,0(%%esp)" : : : "memory" )
-#define xen_wmb() asm volatile ( "" : : : "memory")
+#define xen_rmb() xen_barrier()
+#define xen_wmb() xen_barrier()
 #elif defined(__x86_64__)
 #define xen_mb()  asm volatile ( "mfence" : : : "memory")
-#define xen_rmb() asm volatile ( "lfence" : : : "memory")
-#define xen_wmb() asm volatile ( "" : : : "memory")
+#define xen_rmb() xen_barrier()
+#define xen_wmb() xen_barrier()
 #elif defined(__ia64__)
 #define xen_mb()   asm volatile ("mf" ::: "memory")
 #define xen_rmb()  asm volatile ("mf" ::: "memory")