[PATCH] Makefile: Unset stack-protector gcc flag if it is not supported

From: Markos Chandras
Date: Fri Feb 07 2014 - 12:15:29 EST


In case the compiler does not support the stack-protector option,
unset the flag to avoid build failures. Printing a warning is enough
to let the user know that this flag will not be used.
Fixes the following build problem when using a toolchain which does
not support the -fstack-protector-strong flag:

Makefile:614: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG:
-fstack-protector-strong not supported by compiler
mips-linux-gnu-gcc: error: unrecognized command line option
'-fstack-protector-strong'
scripts/Makefile.build:308: recipe for target 'scripts/mod/empty.o' failed
make[2]: *** [scripts/mod/empty.o] Error 1
make[2]: *** Waiting for unfinished jobs....
scripts/Makefile.build:455: recipe for target 'scripts/mod' failed

Cc: Michal Marek <mmarek@xxxxxxx>
Cc: linux-kbuild@xxxxxxxxxxxxxxx
Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
Makefile | 2 ++
1 file changed, 2 insertions(+)

diff --git a/Makefile b/Makefile
index 606ef7c..63a5333 100644
--- a/Makefile
+++ b/Makefile
@@ -607,12 +607,14 @@ ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
ifeq ($(call cc-option, $(stackp-flag)),)
$(warning Cannot use CONFIG_CC_STACKPROTECTOR: \
-fstack-protector not supported by compiler))
+ stackp-flag :=
endif
else ifdef CONFIG_CC_STACKPROTECTOR_STRONG
stackp-flag := -fstack-protector-strong
ifeq ($(call cc-option, $(stackp-flag)),)
$(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \
-fstack-protector-strong not supported by compiler)
+ stackp-flag :=
endif
else
# Force off for distro compilers that enable stack protector by default.
--
1.8.5.4


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