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@linux.intel.com>
Link: http://lkml.kernel.org/r/1332960678-11879-1-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
This commit is contained in:
Andi Kleen 2012-03-28 11:51:17 -07:00 committed by H. Peter Anvin
parent f6365201d8
commit c0e9afc0da

View File

@ -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)