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authorAndi Kleen <andi@firstfloor.org>2008-02-22 15:15:03 +0100
committerSam Ravnborg <sam@uranus.ravnborg.org>2008-04-25 20:23:47 +0200
commit35bb5b1e0e84cfa1a8906f7e6a77f391ff315791 (patch)
treefd3fa4e426bd11df3496141d8a251a783bce5f8d
parent80ff26241623875636674a31c0540a78c0fb5433 (diff)
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op-kernel-dev-35bb5b1e0e84cfa1a8906f7e6a77f391ff315791.tar.gz
Add option to enable -Wframe-larger-than= on gcc 4.4
Add option to enable -Wframe-larger-than= on gcc 4.4 gcc mainline (upcoming 4.4) added a new -Wframe-larger-than=... option to warn at build time about too large stack frames. Add a config option to enable this warning, since this very useful for the kernel. I choose (somewhat arbitarily) 2048 as default warning threshold for 64bit and 1024 as default for 32bit architectures. With some research and fixing all the code for smaller values these defaults should be probably lowered. With the default allyesconfigs have some new warnings, but I think that is all code that should be just fixed. At some point (when gcc 4.4 is released and widely used) this should obsolete make checkstack Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
-rw-r--r--Makefile4
-rw-r--r--lib/Kconfig.debug11
2 files changed, 15 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 6ae7fd4..c6d331b 100644
--- a/Makefile
+++ b/Makefile
@@ -507,6 +507,10 @@ else
KBUILD_CFLAGS += -O2
endif
+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
# Arch Makefiles may override this setting
KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 623ef24..754cc00 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -25,6 +25,17 @@ config ENABLE_MUST_CHECK
suppress the "warning: ignoring return value of 'foo', declared with
attribute warn_unused_result" messages.
+config FRAME_WARN
+ int "Warn for stack frames larger than (needs gcc 4.4)"
+ range 0 8192
+ default 1024 if !64BIT
+ default 2048 if 64BIT
+ help
+ Tell gcc to warn at build time for stack frames larger than this.
+ Setting this too low will cause a lot of warnings.
+ Setting it to 0 disables the warning.
+ Requires gcc 4.4
+
config MAGIC_SYSRQ
bool "Magic SysRq key"
depends on !UML
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