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-rw-r--r--Documentation/kbuild/gcc-plugins.rst41
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.