On Thu, Feb 11, 2016 at 2:43 PM, Emese Revfy <re.emese@xxxxxxxxx> wrote: > This is the GCC infrastructure documentation about its operation, how to add > and use a new plugin with an example. > --- > Documentation/gcc-plugins.txt | 68 +++++++++++++++++++++++++++++++++++++++++++ > arch/Kconfig | 2 ++ > 2 files changed, 70 insertions(+) > create mode 100644 Documentation/gcc-plugins.txt > > diff --git a/Documentation/gcc-plugins.txt b/Documentation/gcc-plugins.txt > new file mode 100644 > index 0000000..e1171c2 > --- /dev/null > +++ b/Documentation/gcc-plugins.txt > @@ -0,0 +1,68 @@ > +GCC plugin infrastructure > +========================= > + > + > +1. Introduction > +=============== > + > +GCC plugins are loadable modules that provide extra features to the > +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. > + > +Currently the GCC plugin infrastructure supports only the x86 architecture. What's needed to support other architectures? > + > +This infrastructure was ported from grsecurity [6] and PaX [7]. > + > +-- > +[1] https://gcc.gnu.org/onlinedocs/gccint/Plugins.html > +[2] https://gcc.gnu.org/onlinedocs/gccint/Plugin-API.html#Plugin-API > +[3] https://gcc.gnu.org/onlinedocs/gccint/GIMPLE.html > +[4] https://gcc.gnu.org/onlinedocs/gccint/IPA.html > +[5] https://gcc.gnu.org/onlinedocs/gccint/RTL.html > +[6] https://grsecurity.net/ > +[7] https://pax.grsecurity.net/ > + > + > +2. Files > +======== > + > +$(src)/tools/gcc > + This is the directory of the GCC plugins. > + > +$(src)/tools/gcc/gcc-common.h > + This is a compatibility header for GCC plugins. > + It should be always included instead of individual gcc headers. > + > +$(src)/scripts/gcc-plugin.sh > + This script checks the availability of the included headers in > + gcc-common.h and chooses the proper host compiler to build the plugins > + (gcc-4.7 can be built by either gcc or g++). The part about the proper host compiler isn't clear to me. It looks like each of three compilers are examined: $CC for the header location $HOSTCC for actually doing the build, or $HOSTCXX for doing the plugin build? Shouldn't the headers be coming from the compiler that is actually going to be used to build the .so file? > + > + > +3. Usage > +======== > + > +Enable a GCC plugin based feature in the kernel config: > + > + CONFIG_GCC_PLUGIN_CYC_COMPLEXITY = y > + > +To compile only the plugin(s): > + > + make gcc-plugins > + > +or just run the kernel make and compile the whole kernel with > +the cyclomatic complexity GCC plugin. > + > + > +4. How to add a new GCC plugin > +============================== > + > +The GCC plugins are in $(src)/tools/gcc/. You can use a file or a directory > +here. It must be added to $(src)/tools/gcc/Makefile, > +$(src)/scripts/Makefile.gcc-plugins and $(src)/arch/Kconfig. > +See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin. > diff --git a/arch/Kconfig b/arch/Kconfig > index a558ecb..38964dd 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -377,6 +377,8 @@ config GCC_PLUGIN_CYC_COMPLEXITY > N = the number of nodes > P = the number of connected components (exit nodes). > > + See Documentation/gcc-plugins.txt for details. > + > endmenu # "GCC plugins" > > config HAVE_CC_STACKPROTECTOR > -- > 2.4.1 Thanks! I'm looking forward to more plugins. :) -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
