Messages in this thread |  | | Date | Wed, 4 Dec 2013 09:54:48 +0100 | From | Ingo Molnar <> | Subject | Re: [tip:x86/urgent] x86-64, build: Always pass in -mno-sse |
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* tip-bot for H. Peter Anvin <tipbot@zytor.com> wrote:
> Commit-ID: 5551a34e5aeab868f8d37f70d8754868921b4ee5 > Gitweb: http://git.kernel.org/tip/5551a34e5aeab868f8d37f70d8754868921b4ee5 > Author: H. Peter Anvin <hpa@linux.intel.com> > AuthorDate: Wed, 20 Nov 2013 13:31:49 -0800 > Committer: H. Peter Anvin <hpa@linux.intel.com> > CommitDate: Tue, 3 Dec 2013 17:40:22 -0800 > > x86-64, build: Always pass in -mno-sse > > Always pass in the -mno-sse argument, regardless if > -preferred-stack-boundary is supported. We never want to generate SSE > instructions in the kernel unless we *really* know what we're doing. > > According to H. J. Lu, any version of gcc new enough that we support > it at all should handle the -mno-sse option, so just add it > unconditionally. > > Reported-by: Kevin B. Smith <kevin.b.smith@intel.com> > Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> > Cc: H. J. Lu <hjl.tools@gmail.com> > Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org > Cc: <stable@vger.kernel.org> # build fix only > --- > arch/x86/Makefile | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index 41250fb..eda00f9 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -31,6 +31,9 @@ ifeq ($(CONFIG_X86_32),y) > > KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return > > + # Don't autogenerate SSE instructions > + KBUILD_CFLAGS += -mno-sse > + > # Never want PIC in a 32-bit kernel, prevent breakage with GCC built > # with nonstandard options > KBUILD_CFLAGS += -fno-pic > @@ -57,8 +60,11 @@ else > KBUILD_AFLAGS += -m64 > KBUILD_CFLAGS += -m64 > > + # Don't autogenerate SSE instructions > + KBUILD_CFLAGS += -mno-sse > + > # Use -mpreferred-stack-boundary=3 if supported. > - KBUILD_CFLAGS += $(call cc-option,-mno-sse -mpreferred-stack-boundary=3) > + KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=3) > > # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) > cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
Just a detail I noticed: in kbuild we intentionally use 8 spaces for tabs in Makefiles and only use tabs for commands where tabs are required.
The above code introduces tabs in the middle of 8-space sequences. It works but is inconsistent.
Thanks,
Ingo
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