x86-64, build: Always pass in -mno-sse (5551a34e) · Commits · 戴 / test

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

+7 −1

Original line number	Diff line number	Diff line
		@@ -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)

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