linux-kernel - [tip:x86/urgent] x86-64, build: Always pass in -mno-sse

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Date:	Tue, 3 Dec 2013 17:42:56 -0800
From:	"tip-bot for H. Peter Anvin" <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	tglx@...utronix.de, hpa@...ux.intel.com, hjl.tools@...il.com,
	kevin.b.smith@...el.com
Subject: [tip:x86/urgent] x86-64, build: Always pass in -mno-sse

Commit-ID:  5551a34e5aeab868f8d37f70d8754868921b4ee5
Gitweb:     http://git.kernel.org/tip/5551a34e5aeab868f8d37f70d8754868921b4ee5
Author:     H. Peter Anvin <hpa@...ux.intel.com>
AuthorDate: Wed, 20 Nov 2013 13:31:49 -0800
Committer:  H. Peter Anvin <hpa@...ux.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@...el.com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
Cc: H. J. Lu <hjl.tools@...il.com>
Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org
Cc: <stable@...r.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)
--
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