linux-yocto/scripts/gcc-plugins/Kconfig

preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))

config PLUGIN_HOSTCC string default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC help Host compiler used to build GCC plugins. This can be $(HOSTCXX), $(HOSTCC), or a null string if GCC plugin is unsupported.

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 PLUGIN_HOSTCC != "" help GCC plugins are loadable modules that provide extra features to the compiler. They are useful for runtime instrumentation and static analysis.

  See Documentation/gcc-plugins.txt 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 dvyukov@google.com.

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_STRUCTLEAK bool "Force initialization of variables containing userspace addresses" help This plugin zero-initializes any structures containing a __user attribute. This can prevent some classes of information exposures.

  This plugin was ported from grsecurity/PaX. More information at:
   * https://grsecurity.net/
   * https://pax.grsecurity.net/

config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL bool "Force initialize all struct type variables passed by reference" depends on GCC_PLUGIN_STRUCTLEAK depends on !COMPILE_TEST help Zero initialize any struct type local variable that may be passed by reference without having been initialized.

config GCC_PLUGIN_STRUCTLEAK_VERBOSE bool "Report forcefully initialized variables" depends on GCC_PLUGIN_STRUCTLEAK depends on !COMPILE_TEST # too noisy help This option will cause a warning to be printed each time the structleak plugin finds a variable it thinks needs to be initialized. Since not all existing initializers are detected by the plugin, this can produce false positive warnings.

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-plgins/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_STACKLEAK bool "Erase the kernel stack before returning from syscalls" depends on GCC_PLUGINS depends on HAVE_ARCH_STACKLEAK help This option makes the kernel erase the kernel stack before returning from system calls. That reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks.

  The tradeoff is the performance impact: on a single CPU system kernel
  compilation sees a 1% slowdown, other systems and workloads may vary
  and you are advised to test this feature on your expected workload
  before deploying it.

  This plugin was ported from grsecurity/PaX. More information at:
   * https://grsecurity.net/
   * https://pax.grsecurity.net/

config STACKLEAK_TRACK_MIN_SIZE int "Minimum stack frame size of functions tracked by STACKLEAK" default 100 range 0 4096 depends on GCC_PLUGIN_STACKLEAK help The STACKLEAK gcc plugin instruments the kernel code for tracking the lowest border of the kernel stack (and for some other purposes). It inserts the stackleak_track_stack() call for the functions with a stack frame size greater than or equal to this parameter. If unsure, leave the default value 100.

config STACKLEAK_METRICS bool "Show STACKLEAK metrics in the /proc file system" depends on GCC_PLUGIN_STACKLEAK depends on PROC_FS help If this is set, STACKLEAK metrics for every task are available in the /proc file system. In particular, /proc//stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it can be useful for estimating the STACKLEAK performance impact for your workloads.

config STACKLEAK_RUNTIME_DISABLE bool "Allow runtime disabling of kernel stack erasing" depends on GCC_PLUGIN_STACKLEAK help This option provides 'stack_erasing' sysctl, which can be used in runtime to control kernel stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK.

config GCC_PLUGIN_ARM_SSP_PER_TASK bool depends on GCC_PLUGINS && ARM

endif