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