From 5aadfdeb8de001ca04d500586e3b033404c28617 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 28 May 2018 18:22:04 +0900 Subject: 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 Reviewed-by: Kees Cook --- scripts/gcc-plugins/Makefile | 4 ---- 1 file changed, 4 deletions(-) (limited to 'scripts/gcc-plugins') diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index e2ff425f4c7e..ea465799ced5 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -13,10 +13,6 @@ else export HOST_EXTRACXXFLAGS endif -ifneq ($(CFLAGS_KCOV), $(SANCOV_PLUGIN)) - GCC_PLUGIN := $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGIN)) -endif - export HOSTLIBS $(obj)/randomize_layout_plugin.o: $(objtree)/$(obj)/randomize_layout_seed.h -- cgit v1.2.3 From 59f53855babf757ac7be19995670ab884aaf9b71 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 28 May 2018 18:22:06 +0900 Subject: gcc-plugins: test plugin support in Kconfig and clean up Makefile Run scripts/gcc-plugin.sh from Kconfig so that users can enable GCC_PLUGINS only when the compiler supports building plugins. Kconfig defines a new symbol, PLUGIN_HOSTCC. This will contain the compiler (g++ or gcc) used for building plugins, or empty if the plugin can not be supported at all. This allows us to remove all ugly testing in Makefile.gcc-plugins. Signed-off-by: Masahiro Yamada Acked-by: Kees Cook --- scripts/gcc-plugins/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts/gcc-plugins') diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index ea465799ced5..326254653bd0 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 +PLUGINCC := $(CONFIG_PLUGIN_HOSTCC:"%"=%) GCC_PLUGINS_DIR := $(shell $(CC) -print-file-name=plugin) ifeq ($(PLUGINCC),$(HOSTCC)) -- cgit v1.2.3