scripts/gcc-plugins/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
   3
   4 config PLUGIN_HOSTCC
   5         string
   6         default "$(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
  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
  17 config 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
  28 menu "GCC plugins"
  29         depends on GCC_PLUGINS
  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
  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
 112 config GCC_PLUGIN_ARM_SSP_PER_TASK
 113         bool
 114         depends on GCC_PLUGINS && ARM
 115
 116 endmenu