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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-13 08:40:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-13 08:40:34 -0700
commitbe779f03d563981c65cc7417cc5e0dbbc5b89d30 (patch)
treece0638b1f449e2fe45419567ee287e2c97847836 /Documentation
parentd290ef9305ebaaac884ae0350bfc243dd01d354d (diff)
parent00979ce4fcc90d488c7f27f750097adc6b11bd07 (diff)
Merge tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada: - fix some bugs introduced by the recent Kconfig syntax extension - add some symbols about compiler information in Kconfig, such as CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc. - test compiler capability for the stack protector in Kconfig, and clean-up Makefile - test compiler capability for GCC-plugins in Kconfig, and clean-up Makefile - allow to enable GCC-plugins for COMPILE_TEST - test compiler capability for KCOV in Kconfig and correct dependency - remove auto-detect mode of the GCOV format, which is now more nicely handled in Kconfig - test compiler capability for mprofile-kernel on PowerPC, and clean-up Makefile - misc cleanups * tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify() kconfig: fix localmodconfig sh: remove no-op macro VMLINUX_SYMBOL() powerpc/kbuild: move -mprofile-kernel check to Kconfig Documentation: kconfig: add recommended way to describe compiler support gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST gcc-plugins: test plugin support in Kconfig and clean up Makefile gcc-plugins: move GCC version check for PowerPC to Kconfig kcov: test compiler capability in Kconfig and correct dependency gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig kconfig: add CC_IS_CLANG and CLANG_VERSION kconfig: add CC_IS_GCC and GCC_VERSION stack-protector: test compiler capability in Kconfig and drop AUTO mode kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kbuild/kconfig-language.txt18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index 0e966e8f9ec7..a4eb01843c04 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -473,6 +473,24 @@ config option to 'y' no matter the dependencies.
The dependencies are moved to the symbol GENERIC_IOMAP and we avoid the
situation where select forces a symbol equals to 'y'.
+Adding features that need compiler support
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+There are several features that need compiler support. The recommended way
+to describe the dependency on the compiler feature is to use "depends on"
+followed by a test macro.
+
+config CC_STACKPROTECTOR
+ bool "Stack Protector buffer overflow detection"
+ depends on $(cc-option,-fstack-protector)
+ ...
+
+If you need to expose a compiler capability to makefiles and/or C source files,
+CC_HAS_ is the recommended prefix for the config option.
+
+config CC_HAS_STACKPROTECTOR_NONE
+ def_bool $(cc-option,-fno-stack-protector)
+
Build as module only
~~~~~~~~~~~~~~~~~~~~
To restrict a component build to module-only, qualify its config symbol