1# SPDX-License-Identifier: GPL-2.0-only
  2preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
  3
  4config PLUGIN_HOSTCC
  5	string
  6	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC
  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
 11config HAVE_GCC_PLUGINS
 12	bool
 13	help
 14	  An arch should select this symbol if it supports building with
 15	  GCC plugins.
 16
 17config GCC_PLUGINS
 18	bool
 19	depends on HAVE_GCC_PLUGINS
 20	depends on PLUGIN_HOSTCC != ""
 21	default y
 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
 26	  See Documentation/core-api/gcc-plugins.rst for details.
 27
 28menu "GCC plugins"
 29	depends on GCC_PLUGINS
 30
 31config 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
 47config 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
 55config 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
 72config 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
101config 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
112config GCC_PLUGIN_ARM_SSP_PER_TASK
113	bool
114	depends on GCC_PLUGINS && ARM
115
116endmenu