[tip:x86/urgent] x86: Use -mno-avx when available

From: tip-bot for Andi Kleen
Date: Fri Mar 30 2012 - 13:17:03 EST

Commit-ID: c0e9afc0da6cb0f11497e5ea83377b3c451450e0
Gitweb: http://git.kernel.org/tip/c0e9afc0da6cb0f11497e5ea83377b3c451450e0
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 28 Mar 2012 11:51:17 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Fri, 30 Mar 2012 10:06:39 -0700

x86: Use -mno-avx when available

On gccs that support AVX it's a good idea to disable that too, similar to
how SSE2, SSE1 etc. are already disabled. This prevents the compiler
from generating AVX ever implicitely.

No failure observed, just from review.

[ hpa: Marking this for urgent and stable, simply because the patch
will either have absolutely no effect *or* it will avoid potentially
very hard to debug failures. ]

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1332960678-11879-1-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
arch/x86/Makefile | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 968dbe2..41a7237 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -129,6 +129,7 @@ KBUILD_CFLAGS += -Wno-sign-compare
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# prevent gcc from generating any FP code by mistake
KBUILD_CFLAGS += $(call cc-option,-mno-sse -mno-mmx -mno-sse2 -mno-3dnow,)
+KBUILD_CFLAGS += $(call cc-option,-mno-avx,)

KBUILD_CFLAGS += $(mflags-y)
KBUILD_AFLAGS += $(mflags-y)
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