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 17menuconfig GCC_PLUGINS 18 bool "GCC plugins" 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 28if GCC_PLUGINS 29 30config GCC_PLUGIN_CYC_COMPLEXITY 31 bool "Compute the cyclomatic complexity of a function" if EXPERT 32 depends on !COMPILE_TEST # too noisy 33 help 34 The complexity M of a function's control flow graph is defined as: 35 M = E - N + 2P 36 where 37 38 E = the number of edges 39 N = the number of nodes 40 P = the number of connected components (exit nodes). 41 42 Enabling this plugin reports the complexity to stderr during the 43 build. It mainly serves as a simple example of how to create a 44 gcc plugin for the kernel. 45 46config GCC_PLUGIN_SANCOV 47 bool 48 help 49 This plugin inserts a __sanitizer_cov_trace_pc() call at the start of 50 basic blocks. It supports all gcc versions with plugin support (from 51 gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" 52 by Dmitry Vyukov <dvyukov@google.com>. 53 54config GCC_PLUGIN_LATENT_ENTROPY 55 bool "Generate some entropy during boot and runtime" 56 help 57 By saying Y here the kernel will instrument some kernel code to 58 extract some entropy from both original and artificially created 59 program state. This will help especially embedded systems where 60 there is little 'natural' source of entropy normally. The cost 61 is some slowdown of the boot process (about 0.5%) and fork and 62 irq processing. 63 64 Note that entropy extracted this way is not cryptographically 65 secure! 66 67 This plugin was ported from grsecurity/PaX. More information at: 68 * https://grsecurity.net/ 69 * https://pax.grsecurity.net/ 70 71config GCC_PLUGIN_RANDSTRUCT 72 bool "Randomize layout of sensitive kernel structures" 73 select MODVERSIONS if MODULES 74 help 75 If you say Y here, the layouts of structures that are entirely 76 function pointers (and have not been manually annotated with 77 __no_randomize_layout), or structures that have been explicitly 78 marked with __randomize_layout, will be randomized at compile-time. 79 This can introduce the requirement of an additional information 80 exposure vulnerability for exploits targeting these structure 81 types. 82 83 Enabling this feature will introduce some performance impact, 84 slightly increase memory usage, and prevent the use of forensic 85 tools like Volatility against the system (unless the kernel 86 source tree isn't cleaned after kernel installation). 87 88 The seed used for compilation is located at 89 scripts/gcc-plgins/randomize_layout_seed.h. It remains after 90 a make clean to allow for external modules to be compiled with 91 the existing seed and will be removed by a make mrproper or 92 make distclean. 93 94 Note that the implementation requires gcc 4.7 or newer. 95 96 This plugin was ported from grsecurity/PaX. More information at: 97 * https://grsecurity.net/ 98 * https://pax.grsecurity.net/ 99 100config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE 101 bool "Use cacheline-aware structure randomization" 102 depends on GCC_PLUGIN_RANDSTRUCT 103 depends on !COMPILE_TEST # do not reduce test coverage 104 help 105 If you say Y here, the RANDSTRUCT randomization will make a 106 best effort at restricting randomization to cacheline-sized 107 groups of elements. It will further not randomize bitfields 108 in structures. This reduces the performance hit of RANDSTRUCT 109 at the cost of weakened randomization. 110 111config GCC_PLUGIN_ARM_SSP_PER_TASK 112 bool 113 depends on GCC_PLUGINS && ARM 114 115endif 116