[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-trivial] [PATCH] qemu-barrier: Fix compiler version check for
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-trivial] [PATCH] qemu-barrier: Fix compiler version check for future gcc versions |
Date: |
Mon, 8 Oct 2012 22:01:20 +0200 |
On Wed, Oct 03, 2012 at 11:11:02PM +0200, Stefan Weil wrote:
> 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 <address@hidden>
> ---
>
> With current gcc versions (gcc-4.x) there is no problem.
> Nevertheless, I suggest to fix this in stable versions, too.
>
> Regards
>
> Stefan Weil
ACK for stable tree.
> 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