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authorMasahiro Yamada <yamada.masahiro@socionext.com>2018-05-28 18:22:04 +0900
committerMasahiro Yamada <yamada.masahiro@socionext.com>2018-06-11 09:14:08 +0900
commit5aadfdeb8de001ca04d500586e3b033404c28617 (patch)
treea430e73a414b972a4a4cb71ba98fad5af960254d /Makefile
parent6a61b70b43c9c4cbc7314bf6c8b5ba8b0d6e1e7b (diff)
downloadlwn-5aadfdeb8de001ca04d500586e3b033404c28617.tar.gz
lwn-5aadfdeb8de001ca04d500586e3b033404c28617.zip
kcov: test compiler capability in Kconfig and correct dependency
As Documentation/kbuild/kconfig-language.txt notes, 'select' should be be used with care - it forces a lower limit of another symbol, ignoring the dependency. Currently, KCOV can select GCC_PLUGINS even if arch does not select HAVE_GCC_PLUGINS. This could cause the unmet direct dependency. Now that Kconfig can test compiler capability, let's handle this in a more sophisticated way. There are two ways to enable KCOV; use the compiler that natively supports -fsanitize-coverage=trace-pc, or build the SANCOV plugin if the compiler has ability to build GCC plugins. Hence, the correct dependency for KCOV is: depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS You do not need to build the SANCOV plugin if the compiler already supports -fsanitize-coverage=trace-pc. Hence, the select should be: select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC With this, GCC_PLUGIN_SANCOV is selected only when necessary, so scripts/Makefile.gcc-plugins can be cleaner. I also cleaned up Kconfig and scripts/Makefile.kcov as well. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index ca9d98b4a71b..73f0bb2c7a98 100644
--- a/Makefile
+++ b/Makefile
@@ -601,7 +601,7 @@ all: vmlinux
CFLAGS_GCOV := -fprofile-arcs -ftest-coverage \
$(call cc-option,-fno-tree-loop-im) \
$(call cc-disable-warning,maybe-uninitialized,)
-export CFLAGS_GCOV CFLAGS_KCOV
+export CFLAGS_GCOV
# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
# values of the respective KBUILD_* variables