gcc-plugins: Add support for plugin subdirectories

This adds support for building more complex gcc plugins that live in a
subdirectory instead of just in a single source file.

Reported-by: PaX Team

gcc-plugins: Add support for plugin subdirectories

This adds support for building more complex gcc plugins that live in a
subdirectory instead of just in a single source file.

Reported-by: PaX Team <[email protected]>
Signed-off-by: Emese Revfy <[email protected]>
[kees: clarified commit message]
Signed-off-by: Kees Cook <[email protected]>

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gcc-plugins: Add support for passing plugin arguments

The latent_entropy plugin needs to pass arguments, so this adds the
support.

Signed-off-by: Emese Revfy <[email protected]>
Signed-off-by: Kee

gcc-plugins: Add support for passing plugin arguments

The latent_entropy plugin needs to pass arguments, so this adds the
support.

Signed-off-by: Emese Revfy <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

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gcc-plugins: abort builds cleanly when not supported

When the compiler doesn't support gcc plugins (either due to missing
headers or too old a version), report the problem and abort the build
instea

gcc-plugins: abort builds cleanly when not supported

When the compiler doesn't support gcc plugins (either due to missing
headers or too old a version), report the problem and abort the build
instead of emitting a warning and letting the build founder with arcane
compiler errors.

Signed-off-by: Kees Cook <[email protected]>

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Add sancov plugin

The sancov gcc plugin inserts a __sanitizer_cov_trace_pc() call
at the start of basic blocks.

This plugin is a helper plugin for the kcov feature. It supports
all gcc versions wit

Add sancov plugin

The sancov gcc plugin inserts a __sanitizer_cov_trace_pc() call
at the start of basic blocks.

This plugin is a helper plugin for the kcov feature. It supports
all gcc versions with plugin support (from gcc-4.5 on).
It is based on the gcc commit "Add fuzzing coverage support" by Dmitry Vyukov
(https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296).

Signed-off-by: Emese Revfy <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: Michal Marek <[email protected]>

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Add Cyclomatic complexity GCC plugin

Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC
plugin computes the cyclomatic complexity of each function.

The complexity M of

Add Cyclomatic complexity GCC plugin

Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC
plugin computes the cyclomatic complexity of each function.

The complexity M of a function's control flow graph is defined as:
M = E - N + 2P
where
E = the number of edges
N = the number of nodes
P = the number of connected components (exit nodes).

Signed-off-by: Emese Revfy <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: Michal Marek <[email protected]>

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GCC plugin infrastructure

This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a

GCC plugin infrastructure

This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a separate directory. Cross-compilation is supported too.
Currently the x86, arm, arm64 and uml architectures enable plugins.

The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
there. The plugins compile with these options:
* -fno-rtti: gcc is compiled with this option so the plugins must use it too
* -fno-exceptions: this is inherited from gcc too
* -fasynchronous-unwind-tables: this is inherited from gcc too
* -ggdb: it is useful for debugging a plugin (better backtrace on internal
errors)
* -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
* -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
variable, plugin-version.h)

The infrastructure introduces a new Makefile target called gcc-plugins. It
supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
This script also checks the availability of the included headers in
scripts/gcc-plugins/gcc-common.h.

The gcc-common.h header contains frequently included headers for GCC plugins
and it has a compatibility layer for the supported gcc versions.

The gcc-generate-*-pass.h headers automatically generate the registration
structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.

Note that 'make clean' keeps the *.so files (only the distclean or mrproper
targets clean all) because they are needed for out-of-tree modules.

Based on work created by the PaX Team.

Signed-off-by: Emese Revfy <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: Michal Marek <[email protected]>

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