1# SPDX-License-Identifier: GPL-2.0-only
2config HAVE_ARCH_KMSAN
3	bool
4
5config HAVE_KMSAN_COMPILER
6	# Clang versions <14.0.0 also support -fsanitize=kernel-memory, but not
7	# all the features necessary to build the kernel with KMSAN.
8	depends on CC_IS_CLANG && CLANG_VERSION >= 140000
9	def_bool $(cc-option,-fsanitize=kernel-memory -mllvm -msan-disable-checks=1)
10
11config KMSAN
12	bool "KMSAN: detector of uninitialized values use"
13	depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER
14	depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN
15	depends on !PREEMPT_RT
16	select STACKDEPOT
17	select STACKDEPOT_ALWAYS_INIT
18	help
19	  KernelMemorySanitizer (KMSAN) is a dynamic detector of uses of
20	  uninitialized values in the kernel. It is based on compiler
21	  instrumentation provided by Clang and thus requires Clang to build.
22
23	  An important note is that KMSAN is not intended for production use,
24	  because it drastically increases kernel memory footprint and slows
25	  the whole system down.
26
27	  See <file:Documentation/dev-tools/kmsan.rst> for more details.
28
29if KMSAN
30
31config HAVE_KMSAN_PARAM_RETVAL
32	# -fsanitize-memory-param-retval is supported only by Clang >= 14.
33	depends on HAVE_KMSAN_COMPILER
34	def_bool $(cc-option,-fsanitize=kernel-memory -fsanitize-memory-param-retval)
35
36config KMSAN_CHECK_PARAM_RETVAL
37	bool "Check for uninitialized values passed to and returned from functions"
38	default y
39	depends on HAVE_KMSAN_PARAM_RETVAL
40	help
41	  If the compiler supports -fsanitize-memory-param-retval, KMSAN will
42	  eagerly check every function parameter passed by value and every
43	  function return value.
44
45	  Disabling KMSAN_CHECK_PARAM_RETVAL will result in tracking shadow for
46	  function parameters and return values across function borders. This
47	  is a more relaxed mode, but it generates more instrumentation code and
48	  may potentially report errors in corner cases when non-instrumented
49	  functions call instrumented ones.
50
51config KMSAN_KUNIT_TEST
52	tristate "KMSAN integration test suite" if !KUNIT_ALL_TESTS
53	default KUNIT_ALL_TESTS
54	depends on TRACEPOINTS && KUNIT
55	help
56	  Test suite for KMSAN, testing various error detection scenarios,
57	  and checking that reports are correctly output to console.
58
59	  Say Y here if you want the test to be built into the kernel and run
60	  during boot; say M if you want the test to build as a module; say N
61	  if you are unsure.
62
63endif
64