VisionFive2 Linux kernel

0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  1) # SPDX-License-Identifier: GPL-2.0-only
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  2) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  3) config HAVE_ARCH_KFENCE
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  4) 	bool
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  5) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  6) menuconfig KFENCE
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  7) 	bool "KFENCE: low-overhead sampling-based memory safety error detector"
2b8305260fb37 (Alexander Potapenko 2021-02-25 17:19:21 -0800  8) 	depends on HAVE_ARCH_KFENCE && (SLAB || SLUB)
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800  9) 	select STACKTRACE
407f1d8c1b5f3 (Marco Elver         2021-05-04 18:40:21 -0700 10) 	select IRQ_WORK
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 11) 	help
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 12) 	  KFENCE is a low-overhead sampling-based detector of heap out-of-bounds
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 13) 	  access, use-after-free, and invalid-free errors. KFENCE is designed
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 14) 	  to have negligible cost to permit enabling it in production
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 15) 	  environments.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 16) 
10efe55f883f2 (Marco Elver         2021-02-25 17:19:26 -0800 17) 	  See <file:Documentation/dev-tools/kfence.rst> for more details.
10efe55f883f2 (Marco Elver         2021-02-25 17:19:26 -0800 18) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 19) 	  Note that, KFENCE is not a substitute for explicit testing with tools
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 20) 	  such as KASAN. KFENCE can detect a subset of bugs that KASAN can
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 21) 	  detect, albeit at very different performance profiles. If you can
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 22) 	  afford to use KASAN, continue using KASAN, for example in test
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 23) 	  environments. If your kernel targets production use, and cannot
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 24) 	  enable KASAN due to its cost, consider using KFENCE.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 25) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 26) if KFENCE
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 27) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 28) config KFENCE_STATIC_KEYS
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 29) 	bool "Use static keys to set up allocations"
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 30) 	default y
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 31) 	depends on JUMP_LABEL # To ensure performance, require jump labels
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 32) 	help
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 33) 	  Use static keys (static branches) to set up KFENCE allocations. Using
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 34) 	  static keys is normally recommended, because it avoids a dynamic
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 35) 	  branch in the allocator's fast path. However, with very low sample
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 36) 	  intervals, or on systems that do not support jump labels, a dynamic
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 37) 	  branch may still be an acceptable performance trade-off.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 38) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 39) config KFENCE_SAMPLE_INTERVAL
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 40) 	int "Default sample interval in milliseconds"
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 41) 	default 100
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 42) 	help
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 43) 	  The KFENCE sample interval determines the frequency with which heap
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 44) 	  allocations will be guarded by KFENCE. May be overridden via boot
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 45) 	  parameter "kfence.sample_interval".
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 46) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 47) 	  Set this to 0 to disable KFENCE by default, in which case only
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 48) 	  setting "kfence.sample_interval" to a non-zero value enables KFENCE.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 49) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 50) config KFENCE_NUM_OBJECTS
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 51) 	int "Number of guarded objects available"
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 52) 	range 1 65535
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 53) 	default 255
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 54) 	help
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 55) 	  The number of guarded objects available. For each KFENCE object, 2
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 56) 	  pages are required; with one containing the object and two adjacent
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 57) 	  ones used as guard pages.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 58) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 59) config KFENCE_STRESS_TEST_FAULTS
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 60) 	int "Stress testing of fault handling and error reporting" if EXPERT
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 61) 	default 0
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 62) 	help
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 63) 	  The inverse probability with which to randomly protect KFENCE object
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 64) 	  pages, resulting in spurious use-after-frees. The main purpose of
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 65) 	  this option is to stress test KFENCE with concurrent error reports
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 66) 	  and allocations/frees. A value of 0 disables stress testing logic.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 67) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 68) 	  Only for KFENCE testing; set to 0 if you are not a KFENCE developer.
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 69) 
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 70) config KFENCE_KUNIT_TEST
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 71) 	tristate "KFENCE integration test suite" if !KUNIT_ALL_TESTS
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 72) 	default KUNIT_ALL_TESTS
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 73) 	depends on TRACEPOINTS && KUNIT
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 74) 	help
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 75) 	  Test suite for KFENCE, testing various error detection scenarios with
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 76) 	  various allocation types, and checking that reports are correctly
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 77) 	  output to console.
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 78) 
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 79) 	  Say Y here if you want the test to be built into the kernel and run
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 80) 	  during boot; say M if you want the test to build as a module; say N
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 81) 	  if you are unsure.
bc8fbc5f305ae (Marco Elver         2021-02-25 17:19:31 -0800 82) 
0ce20dd840897 (Alexander Potapenko 2021-02-25 17:18:53 -0800 83) endif # KFENCE