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- # SPDX-License-Identifier: GPL-2.0-only
- config HAVE_GCC_PLUGINS
- bool
- help
- An arch should select this symbol if it supports building with
- GCC plugins.
- menuconfig GCC_PLUGINS
- bool "GCC plugins"
- depends on HAVE_GCC_PLUGINS
- depends on CC_IS_GCC
- depends on $(success,test -e $(shell,$(CC) -print-file-name=plugin)/include/plugin-version.h)
- default y
- help
- GCC plugins are loadable modules that provide extra features to the
- compiler. They are useful for runtime instrumentation and static analysis.
- See Documentation/kbuild/gcc-plugins.rst for details.
- if GCC_PLUGINS
- config GCC_PLUGIN_CYC_COMPLEXITY
- bool "Compute the cyclomatic complexity of a function" if EXPERT
- depends on !COMPILE_TEST # too noisy
- help
- 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).
- Enabling this plugin reports the complexity to stderr during the
- build. It mainly serves as a simple example of how to create a
- gcc plugin for the kernel.
- config GCC_PLUGIN_SANCOV
- bool
- help
- This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
- basic blocks. It supports all gcc versions with plugin support (from
- gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
- by Dmitry Vyukov <[email protected]>.
- config GCC_PLUGIN_LATENT_ENTROPY
- bool "Generate some entropy during boot and runtime"
- help
- By saying Y here the kernel will instrument some kernel code to
- extract some entropy from both original and artificially created
- program state. This will help especially embedded systems where
- there is little 'natural' source of entropy normally. The cost
- is some slowdown of the boot process (about 0.5%) and fork and
- irq processing.
- Note that entropy extracted this way is not cryptographically
- secure!
- This plugin was ported from grsecurity/PaX. More information at:
- * https://grsecurity.net/
- * https://pax.grsecurity.net/
- config GCC_PLUGIN_RANDSTRUCT
- bool "Randomize layout of sensitive kernel structures"
- select MODVERSIONS if MODULES
- help
- If you say Y here, the layouts of structures that are entirely
- function pointers (and have not been manually annotated with
- __no_randomize_layout), or structures that have been explicitly
- marked with __randomize_layout, will be randomized at compile-time.
- This can introduce the requirement of an additional information
- exposure vulnerability for exploits targeting these structure
- types.
- Enabling this feature will introduce some performance impact,
- slightly increase memory usage, and prevent the use of forensic
- tools like Volatility against the system (unless the kernel
- source tree isn't cleaned after kernel installation).
- The seed used for compilation is located at
- scripts/gcc-plugins/randomize_layout_seed.h. It remains after
- a make clean to allow for external modules to be compiled with
- the existing seed and will be removed by a make mrproper or
- make distclean.
- Note that the implementation requires gcc 4.7 or newer.
- This plugin was ported from grsecurity/PaX. More information at:
- * https://grsecurity.net/
- * https://pax.grsecurity.net/
- config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
- bool "Use cacheline-aware structure randomization"
- depends on GCC_PLUGIN_RANDSTRUCT
- depends on !COMPILE_TEST # do not reduce test coverage
- help
- If you say Y here, the RANDSTRUCT randomization will make a
- best effort at restricting randomization to cacheline-sized
- groups of elements. It will further not randomize bitfields
- in structures. This reduces the performance hit of RANDSTRUCT
- at the cost of weakened randomization.
- config GCC_PLUGIN_ARM_SSP_PER_TASK
- bool
- depends on GCC_PLUGINS && ARM
- endif
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