[linux-2.6-block.git] / scripts / gcc-plugins / Kconfig

# SPDX-License-Identifier: GPL-2.0-only
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.

config GCC_PLUGINS
	bool
	depends on HAVE_GCC_PLUGINS
	depends on PLUGIN_HOSTCC != ""
	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/core-api/gcc-plugins.rst for details.

menu "GCC plugins"
	depends on 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_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_ARM_SSP_PER_TASK
	bool
	depends on GCC_PLUGINS && ARM

endmenu
Commit	Line	Data
ec8f24b7	1	# SPDX-License-Identifier: GPL-2.0-only
45332b1b MY	2	preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
	3
	4	config PLUGIN_HOSTCC
	5	string
b0441333	6	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC
45332b1b MY	7	help
	8	Host compiler used to build GCC plugins. This can be $(HOSTCXX),
	9	$(HOSTCC), or a null string if GCC plugin is unsupported.
	10
	11	config HAVE_GCC_PLUGINS
	12	bool
	13	help
	14	An arch should select this symbol if it supports building with
	15	GCC plugins.
	16
9f671e58 KC	17	config GCC_PLUGINS
9f671e58 KC	18	bool
45332b1b MY	19	depends on HAVE_GCC_PLUGINS
45332b1b MY	20	depends on PLUGIN_HOSTCC != ""
9f671e58	21	default y
45332b1b MY	22	help
	23	GCC plugins are loadable modules that provide extra features to the
	24	compiler. They are useful for runtime instrumentation and static analysis.
	25
d5ccd65a	26	See Documentation/core-api/gcc-plugins.rst for details.
45332b1b	27
9f671e58 KC	28	menu "GCC plugins"
9f671e58 KC	29	depends on GCC_PLUGINS
45332b1b MY	30
	31	config GCC_PLUGIN_CYC_COMPLEXITY
	32	bool "Compute the cyclomatic complexity of a function" if EXPERT
	33	depends on !COMPILE_TEST # too noisy
	34	help
	35	The complexity M of a function's control flow graph is defined as:
	36	M = E - N + 2P
	37	where
	38
	39	E = the number of edges
	40	N = the number of nodes
	41	P = the number of connected components (exit nodes).
	42
	43	Enabling this plugin reports the complexity to stderr during the
	44	build. It mainly serves as a simple example of how to create a
	45	gcc plugin for the kernel.
	46
	47	config GCC_PLUGIN_SANCOV
	48	bool
	49	help
	50	This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
	51	basic blocks. It supports all gcc versions with plugin support (from
	52	gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
	53	by Dmitry Vyukov <dvyukov@google.com>.
	54
	55	config GCC_PLUGIN_LATENT_ENTROPY
	56	bool "Generate some entropy during boot and runtime"
	57	help
	58	By saying Y here the kernel will instrument some kernel code to
	59	extract some entropy from both original and artificially created
	60	program state. This will help especially embedded systems where
	61	there is little 'natural' source of entropy normally. The cost
	62	is some slowdown of the boot process (about 0.5%) and fork and
	63	irq processing.
	64
	65	Note that entropy extracted this way is not cryptographically
	66	secure!
	67
	68	This plugin was ported from grsecurity/PaX. More information at:
	69	* https://grsecurity.net/
	70	* https://pax.grsecurity.net/
	71
45332b1b MY	72	config GCC_PLUGIN_RANDSTRUCT
	73	bool "Randomize layout of sensitive kernel structures"
	74	select MODVERSIONS if MODULES
	75	help
	76	If you say Y here, the layouts of structures that are entirely
	77	function pointers (and have not been manually annotated with
	78	__no_randomize_layout), or structures that have been explicitly
	79	marked with __randomize_layout, will be randomized at compile-time.
	80	This can introduce the requirement of an additional information
	81	exposure vulnerability for exploits targeting these structure
	82	types.
	83
	84	Enabling this feature will introduce some performance impact,
	85	slightly increase memory usage, and prevent the use of forensic
	86	tools like Volatility against the system (unless the kernel
	87	source tree isn't cleaned after kernel installation).
	88
	89	The seed used for compilation is located at
	90	scripts/gcc-plgins/randomize_layout_seed.h. It remains after
	91	a make clean to allow for external modules to be compiled with
	92	the existing seed and will be removed by a make mrproper or
	93	make distclean.
	94
	95	Note that the implementation requires gcc 4.7 or newer.
	96
	97	This plugin was ported from grsecurity/PaX. More information at:
	98	* https://grsecurity.net/
	99	* https://pax.grsecurity.net/
	100
	101	config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
	102	bool "Use cacheline-aware structure randomization"
	103	depends on GCC_PLUGIN_RANDSTRUCT
	104	depends on !COMPILE_TEST # do not reduce test coverage
	105	help
	106	If you say Y here, the RANDSTRUCT randomization will make a
	107	best effort at restricting randomization to cacheline-sized
	108	groups of elements. It will further not randomize bitfields
	109	in structures. This reduces the performance hit of RANDSTRUCT
	110	at the cost of weakened randomization.
	111
189af465 AB	112	config GCC_PLUGIN_ARM_SSP_PER_TASK
	113	bool
	114	depends on GCC_PLUGINS && ARM
	115
9f671e58	116	endmenu