From 1d93f0f03d4d911fdf1dc4ef529d8b2a0c0765f2 Mon Sep 17 00:00:00 2001
From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Fri, 25 Jun 2010 16:56:49 +0200
Subject: Introduce proper compiler barrier

Define barrier() as optimization barrier and replace (potentially
unreliable) asm("") fences.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
 cpu-exec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'cpu-exec.c')

diff --git a/cpu-exec.c b/cpu-exec.c
index 026980a552..525b3b45ee 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -21,6 +21,7 @@
 #include "disas.h"
 #include "tcg.h"
 #include "kvm.h"
+#include "qemu-barrier.h"
 
 #if !defined(CONFIG_SOFTMMU)
 #undef EAX
@@ -233,7 +234,7 @@ int cpu_exec(CPUState *env1)
        use it.  */
     QEMU_BUILD_BUG_ON (sizeof (saved_env_reg) != sizeof (env));
     saved_env_reg = (host_reg_t) env;
-    asm("");
+    barrier();
     env = env1;
 
     if (exit_request) {
@@ -669,7 +670,7 @@ int cpu_exec(CPUState *env1)
 #endif
 
     /* restore global registers */
-    asm("");
+    barrier();
     env = (void *) saved_env_reg;
 
     /* fail safe : never use cpu_single_env outside cpu_exec() */
-- 
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