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 117