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| -rw-r--r-- | Documentation/kbuild/gcc-plugins.rst | 41 |
1 files changed, 21 insertions, 20 deletions
diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst index 63379d0150e3..3349966f213d 100644 --- a/Documentation/kbuild/gcc-plugins.rst +++ b/Documentation/kbuild/gcc-plugins.rst @@ -11,16 +11,13 @@ compiler [1]_. They are useful for runtime instrumentation and static analysis. We can analyse, change and add further code during compilation via callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_. -The GCC plugin infrastructure of the kernel supports all gcc versions from -4.5 to 6.0, building out-of-tree modules, cross-compilation and building in a -separate directory. -Plugin source files have to be compilable by both a C and a C++ compiler as well -because gcc versions 4.5 and 4.6 are compiled by a C compiler, -gcc-4.7 can be compiled by a C or a C++ compiler, -and versions 4.8+ can only be compiled by a C++ compiler. +The GCC plugin infrastructure of the kernel supports building out-of-tree +modules, cross-compilation and building in a separate directory. +Plugin source files have to be compilable by a C++ compiler. -Currently the GCC plugin infrastructure supports only the x86, arm, arm64 and -powerpc architectures. +Currently the GCC plugin infrastructure supports only some architectures. +Grep "select HAVE_GCC_PLUGINS" to find out which architectures support +GCC plugins. This infrastructure was ported from grsecurity [6]_ and PaX [7]_. @@ -53,8 +50,7 @@ $(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h, $(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h** These headers automatically generate the registration structures for - GIMPLE, SIMPLE_IPA, IPA and RTL passes. They support all gcc versions - from 4.5 to 6.0. + GIMPLE, SIMPLE_IPA, IPA and RTL passes. They should be preferred to creating the structures by hand. @@ -62,21 +58,25 @@ Usage ===== You must install the gcc plugin headers for your gcc version, -e.g., on Ubuntu for gcc-4.9:: +e.g., on Ubuntu for gcc-10:: - apt-get install gcc-4.9-plugin-dev + apt-get install gcc-10-plugin-dev Or on Fedora:: dnf install gcc-plugin-devel -Enable a GCC plugin based feature in the kernel config:: +Enable the GCC plugin infrastructure and some plugin(s) you want to use +in the kernel config:: - CONFIG_GCC_PLUGIN_CYC_COMPLEXITY = y + CONFIG_GCC_PLUGINS=y + CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y + CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y + ... -To compile only the plugin(s):: +To compile the minimum tool set including the plugin(s):: - make gcc-plugins + make scripts or just run the kernel make and compile the whole kernel with the cyclomatic complexity GCC plugin. @@ -85,7 +85,8 @@ the cyclomatic complexity GCC plugin. 4. How to add a new GCC plugin ============================== -The GCC plugins are in $(src)/scripts/gcc-plugins/. You can use a file or a directory -here. It must be added to $(src)/scripts/gcc-plugins/Makefile, -$(src)/scripts/Makefile.gcc-plugins and $(src)/arch/Kconfig. +The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files +right under scripts/gcc-plugins/. Creating subdirectories is not supported. +It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins +and a relevant Kconfig file. See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin. |