Message-ID: <49D13385.5060900@intel.com>
Date: Mon, 30 Mar 2009 14:03:01 -0700
From: Joseph Cihula <joseph.cihula@intel.com>
Reply-To: joseph.cihula@intel.com
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To: linux-kernel@vger.kernel.org, arjan@linux.intel.com, mingo@elte.hu
Subject: [PATCH] x86: disable stack-protector for __restore_processor_state()
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The __restore_processor_state() fn restores %gs on resume from S3.  As
such, it cannot be protected by the stack-protector guard since %gs will
not be correct on function entry.

There are only a few other fns in this file and it should not negatively
impact kernel security that they will also have the stack-protector
guard removed (and so it's not worth moving them to another file).

Without this change, S3 resume on a kernel built with
CONFIG_CC_STACKPROTECTOR_ALL=y will fail.

Signed-off-by:  Joseph Cihula <joseph.cihula@intel.com>

--- ../linux.trees.git/arch/x86/power/Makefile	2009-03-29 
12:12:13.000000000 -0700
+++ arch/x86/power/Makefile	2009-03-30 12:21:19.000000000 -0700
@@ -1,2 +1,7 @@
+# __restore_processor_state() restores %gs after S3 resume and so 
should not
+# itself be stack-protected
+nostackp := $(call cc-option, -fno-stack-protector)
+CFLAGS_cpu_$(BITS).o	:= $(nostackp)
+
obj-$(CONFIG_PM_SLEEP)		+= cpu_$(BITS).o
obj-$(CONFIG_HIBERNATION)	+= hibernate_$(BITS).o hibernate_asm_$(BITS).o


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