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authorLinus Torvalds <torvalds@linux-foundation.org>2009-03-19 11:10:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-19 11:10:17 -0700
commit68df3755e383e6fecf2354a67b08f92f18536594 (patch)
treea5091127ecb61f30c448ec2abb534509791a7d19 /Makefile
parenta1e4ee22863d41a6fbb24310d7951836cb6dafe7 (diff)
downloadvexpress-lsk-68df3755e383e6fecf2354a67b08f92f18536594.tar.gz
Add '-fwrapv' to gcc CFLAGS
This makes sure that gcc doesn't try to optimize away wrapping arithmetic, which the kernel occasionally uses for overflow testing, ie things like if (ptr + offset < ptr) which technically is undefined for non-unsigned types. See http://bugzilla.kernel.org/show_bug.cgi?id=12597 for details. Not all versions of gcc support it, so we need to make it conditional (it looks like it was introduced in gcc-3.4). Reminded-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 2e2f4a4324a..f607658ac89 100644
--- a/Makefile
+++ b/Makefile
@@ -347,6 +347,7 @@ KBUILD_CPPFLAGS := -D__KERNEL__
KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-fno-strict-aliasing -fno-common \
-Werror-implicit-function-declaration
+KBUILD_CFLAGS += $(call cc-option,-fwrapv)
KBUILD_AFLAGS := -D__ASSEMBLY__
# Read KERNELRELEASE from include/config/kernel.release (if it exists)