From: Stefan Weil <sw@weilnetz.de>
To: qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org, Stefan Weil <sw@weilnetz.de>,
qemu-stable@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: [Qemu-devel] [PATCH] qemu-barrier: Fix compiler version check for future gcc versions
Date: Wed, 3 Oct 2012 23:11:02 +0200 [thread overview]
Message-ID: <1349298662-16666-1-git-send-email-sw@weilnetz.de> (raw)
The current check will give a wrong result for gcc-5.x with x < 4.
Using QEMU_GNUC_PREREQ is simpler and fixes that issue.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
With current gcc versions (gcc-4.x) there is no problem.
Nevertheless, I suggest to fix this in stable versions, too.
Regards
Stefan Weil
qemu-barrier.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/qemu-barrier.h b/qemu-barrier.h
index 7e11197..16f0942 100644
--- a/qemu-barrier.h
+++ b/qemu-barrier.h
@@ -19,7 +19,7 @@
* mfence on 32 bit as well, e.g. if built with -march=pentium-m.
* However, on i386, there seem to be known bugs as recently as 4.3.
* */
-#if defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 4
+#if QEMU_GNUC_PREREQ(4, 4)
#define smp_mb() __sync_synchronize()
#else
#define smp_mb() asm volatile("lock; addl $0,0(%%esp) " ::: "memory")
--
1.7.10
next reply other threads:[~2012-10-03 21:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-03 21:11 Stefan Weil [this message]
2012-10-05 13:48 ` [Qemu-devel] [Qemu-trivial] [PATCH] qemu-barrier: Fix compiler version check for future gcc versions Stefan Hajnoczi
2012-10-08 20:01 ` [Qemu-devel] " Michael S. Tsirkin
2012-10-08 20:57 ` Stefan Weil
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