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authorLinus Torvalds <torvalds@linux-foundation.org>2014-01-20 10:26:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-20 10:26:31 -0800
commitad3ab302fd8239a1ddee01e606683c3197ca6908 (patch)
treed4984d29bcc90252118bdf3a0c32d5c1e027fc08 /Makefile
parenta693c46e14c9fdadbcd68ddfa94a4f72495531a9 (diff)
parent8779657d29c0ebcc0c94ede4df2f497baf1b563f (diff)
downloadlinux-ad3ab302fd8239a1ddee01e606683c3197ca6908.tar.gz
Merge branch 'core-stackprotector-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull strong stackprotector support from Ingo Molnar: "This tree adds a CONFIG_CC_STACKPROTECTOR_STRONG=y, a new, stronger stack canary checking method supported by the newest GCC versions (4.9 and later). Here's the 'intensity comparison' between the various protection modes: - defconfig 11430641 kernel text size 36110 function bodies - defconfig + CONFIG_CC_STACKPROTECTOR_REGULAR 11468490 kernel text size (+0.33%) 1015 of 36110 functions are stack-protected (2.81%) - defconfig + CONFIG_CC_STACKPROTECTOR_STRONG via this patch 11692790 kernel text size (+2.24%) 7401 of 36110 functions are stack-protected (20.5%) the strong model comes with non-trivial costs, which is why we preserved the 'regular' and 'none' models as well" * 'core-stackprotector-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile20
1 files changed, 17 insertions, 3 deletions
diff --git a/Makefile b/Makefile
index b8b7f74696b..455fd484b20 100644
--- a/Makefile
+++ b/Makefile
@@ -595,10 +595,24 @@ ifneq ($(CONFIG_FRAME_WARN),0)
KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
endif
-# Force gcc to behave correct even for buggy distributions
-ifndef CONFIG_CC_STACKPROTECTOR
-KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+# Handle stack protector mode.
+ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
+ stackp-flag := -fstack-protector
+ ifeq ($(call cc-option, $(stackp-flag)),)
+ $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \
+ -fstack-protector not supported by compiler))
+ endif
+else ifdef CONFIG_CC_STACKPROTECTOR_STRONG
+ stackp-flag := -fstack-protector-strong
+ ifeq ($(call cc-option, $(stackp-flag)),)
+ $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \
+ -fstack-protector-strong not supported by compiler)
+ endif
+else
+ # Force off for distro compilers that enable stack protector by default.
+ stackp-flag := $(call cc-option, -fno-stack-protector)
endif
+KBUILD_CFLAGS += $(stackp-flag)
# This warning generated too much noise in a regular build.
# Use make W=1 to enable this warning (see scripts/Makefile.build)