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 "Zero initialize stack variables"	help	  While the kernel is built with warnings enabled for any missed	  stack variable initializations, this warning is silenced for	  anything passed by reference to another function, under the	  occasionally misguided assumption that the function will do	  the initialization. As this regularly leads to exploitable	  flaws, this plugin is available to identify and zero-initialize	  such variables, depending on the chosen level of coverage. 	  This plugin was originally ported from grsecurity/PaX. More	  information at:	   * https://grsecurity.net/	   * https://pax.grsecurity.net/ choice	prompt "Coverage"	depends on GCC_PLUGIN_STRUCTLEAK	default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL	help	  This chooses the level of coverage over classes of potentially	  uninitialized variables. The selected class will be	  zero-initialized before use. 	config GCC_PLUGIN_STRUCTLEAK_USER		bool "structs marked for userspace"		help		  Zero-initialize any structures on the stack containing		  a __user attribute. This can prevent some classes of		  uninitialized stack variable exploits and information		  exposures, like CVE-2013-2141:		  https://git.kernel.org/linus/b9e146d8eb3b9eca 	config GCC_PLUGIN_STRUCTLEAK_BYREF		bool "structs passed by reference"		help		  Zero-initialize any structures on the stack that may		  be passed by reference and had not already been		  explicitly initialized. This can prevent most classes		  of uninitialized stack variable exploits and information		  exposures, like CVE-2017-1000410:		  https://git.kernel.org/linus/06e7e776ca4d3654 	config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL		bool "anything passed by reference"		help		  Zero-initialize any stack variables that may be passed		  by reference and had not already been explicitly		  initialized. This is intended to eliminate all classes		  of uninitialized stack variable exploits and information		  exposures. endchoice 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/<pid>/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