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Thomas Gleixnerec8f24b2019-05-19 13:07:45 +01001# SPDX-License-Identifier: GPL-2.0-only
Masahiro Yamada8b59cd82020-04-23 23:23:52 +09002config CC_VERSION_TEXT
3 string
4 default "$(CC_VERSION_TEXT)"
5 help
6 This is used in unclear ways:
7
8 - Re-run Kconfig when the compiler is updated
9 The 'default' property references the environment variable,
10 CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd.
11 When the compiler is updated, Kconfig will be invoked.
12
Bhaskar Chowdhuryf9c8bc42021-02-25 17:22:18 -080013 - Ensure full rebuild when the compiler is updated
Masahiro Yamadace6ed1c2021-03-04 20:37:08 +090014 include/linux/compiler-version.h contains this option in the comment
Alexey Dobriyan0e0345b2021-04-15 20:36:07 +030015 line so fixdep adds include/config/CC_VERSION_TEXT into the
Masahiro Yamadace6ed1c2021-03-04 20:37:08 +090016 auto-generated dependency. When the compiler is updated, syncconfig
17 will touch it and then every file will be rebuilt.
Masahiro Yamada8b59cd82020-04-23 23:23:52 +090018
Masahiro Yamadaa4353892018-05-28 18:22:01 +090019config CC_IS_GCC
Masahiro Yamadaaec6c602021-01-16 08:35:42 +090020 def_bool $(success,test "$(cc-name)" = GCC)
Masahiro Yamadaa4353892018-05-28 18:22:01 +090021
22config GCC_VERSION
23 int
Masahiro Yamadaaec6c602021-01-16 08:35:42 +090024 default $(cc-version) if CC_IS_GCC
Masahiro Yamadaa4353892018-05-28 18:22:01 +090025 default 0
26
Masahiro Yamada469cb732018-05-28 18:22:02 +090027config CC_IS_CLANG
Masahiro Yamadaaec6c602021-01-16 08:35:42 +090028 def_bool $(success,test "$(cc-name)" = Clang)
Sami Tolvanenb744b432020-04-28 15:14:15 -070029
Masahiro Yamada469cb732018-05-28 18:22:02 +090030config CLANG_VERSION
31 int
Masahiro Yamadaaec6c602021-01-16 08:35:42 +090032 default $(cc-version) if CC_IS_CLANG
33 default 0
Masahiro Yamada469cb732018-05-28 18:22:02 +090034
Masahiro Yamadaba64beb2021-03-16 01:12:56 +090035config AS_IS_GNU
36 def_bool $(success,test "$(as-name)" = GNU)
37
38config AS_IS_LLVM
39 def_bool $(success,test "$(as-name)" = LLVM)
40
41config AS_VERSION
42 int
43 # Use clang version if this is the integrated assembler
44 default CLANG_VERSION if AS_IS_LLVM
45 default $(as-version)
46
Masahiro Yamada02aff852021-02-16 12:10:04 +090047config LD_IS_BFD
48 def_bool $(success,test "$(ld-name)" = BFD)
49
50config LD_VERSION
51 int
52 default $(ld-version) if LD_IS_BFD
53 default 0
54
55config LD_IS_LLD
56 def_bool $(success,test "$(ld-name)" = LLD)
Andy Lutomirskic65eacb2016-09-13 14:29:24 -070057
Nathan Chancellord5750cd2020-11-19 13:46:58 -070058config LLD_VERSION
59 int
Masahiro Yamada02aff852021-02-16 12:10:04 +090060 default $(ld-version) if LD_IS_LLD
61 default 0
Nathan Chancellord5750cd2020-11-19 13:46:58 -070062
Miguel Ojeda2f7ab122021-07-03 16:42:57 +020063config RUST_IS_AVAILABLE
64 def_bool $(success,$(srctree)/scripts/rust_is_available.sh)
65 help
66 This shows whether a suitable Rust toolchain is available (found).
67
68 Please see Documentation/rust/quick-start.rst for instructions on how
Colin Ian Kingeacf96d2022-10-07 21:43:39 +010069 to satisfy the build requirements of Rust support.
Miguel Ojeda2f7ab122021-07-03 16:42:57 +020070
71 In particular, the Makefile target 'rustavailable' is useful to check
72 why the Rust toolchain is not being detected.
73
Masahiro Yamada1a927fd2019-07-01 09:58:39 +090074config CC_CAN_LINK
Masahiro Yamada9371f862020-04-29 12:45:13 +090075 bool
Elliot Bermanf67695c92022-02-01 13:35:42 -080076 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
77 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag))
Masahiro Yamada1a927fd2019-07-01 09:58:39 +090078
Masahiro Yamadab1183b62020-05-09 16:39:15 +090079config CC_CAN_LINK_STATIC
80 bool
Elliot Bermanf67695c92022-02-01 13:35:42 -080081 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT
82 default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
Andy Lutomirskic65eacb2016-09-13 14:29:24 -070083
Nick Desaulniers587f1702020-02-14 14:18:11 -080084config CC_HAS_ASM_GOTO_OUTPUT
Nick Desaulniers587f1702020-02-14 14:18:11 -080085 def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
86
Sean Christopherson1aa0e8b2022-02-02 00:49:41 +000087config CC_HAS_ASM_GOTO_TIED_OUTPUT
88 depends on CC_HAS_ASM_GOTO_OUTPUT
89 # Detect buggy gcc and clang, fixed in gcc-11 clang-14.
Alexandre Belloni534bd702022-11-15 12:01:58 +010090 def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
Sean Christopherson1aa0e8b2022-02-02 00:49:41 +000091
Peter Collingbourne5cf896fb62019-07-31 18:18:42 -070092config TOOLS_SUPPORT_RELR
Will Deacon2d122942019-08-20 10:11:54 +010093 def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
Peter Collingbourne5cf896fb62019-07-31 18:18:42 -070094
Rasmus Villemoeseb111862019-09-13 00:19:25 +020095config CC_HAS_ASM_INLINE
96 def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
97
Nick Desaulniers51c2ee62021-06-21 16:18:22 -070098config CC_HAS_NO_PROFILE_FN_ATTR
99 def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
100
Nathan Chancellor613fe162022-02-01 13:56:21 -0700101config PAHOLE_VERSION
102 int
103 default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))
104
Peter Oberparleiterb99b87f72009-06-17 16:28:03 -0700105config CONSTRUCTORS
106 bool
Peter Oberparleiterb99b87f72009-06-17 16:28:03 -0700107
Peter Zijlstrae360adb2010-10-14 14:01:34 +0800108config IRQ_WORK
109 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +0800110
Shile Zhang10916702019-12-04 08:46:31 +0800111config BUILDTIME_TABLE_SORT
David Daney1dbdc6f2012-04-19 14:59:57 -0700112 bool
113
Andy Lutomirskic65eacb2016-09-13 14:29:24 -0700114config THREAD_INFO_IN_TASK
115 bool
116 help
117 Select this to move thread_info off the stack into task_struct. To
118 make this work, an arch will need to remove all thread_info fields
119 except flags and fix any runtime bugs.
120
Andy Lutomirskic6c314a2016-09-15 22:45:43 -0700121 One subtle change that will be needed is to use try_get_task_stack()
122 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
123
Al Boldiff0cfc62007-07-31 00:39:23 -0700124menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126config BROKEN
127 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129config BROKEN_ON_SMP
130 bool
131 depends on BROKEN || !SMP
132 default y
133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134config INIT_ENV_ARG_LIMIT
135 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -0700136 default 32 if !UML
137 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 help
Randy Dunlap34ad92c22005-10-30 15:01:46 -0800139 Maximum of each of the number of arguments and environment
140 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Jiri Slaby4bb16672013-05-22 10:56:24 +0200142config COMPILE_TEST
143 bool "Compile also drivers which will not load"
Masahiro Yamadaea29b202021-03-12 21:07:08 -0800144 depends on HAS_IOMEM
Jiri Slaby4bb16672013-05-22 10:56:24 +0200145 help
146 Some drivers can be compiled on a different platform than they are
147 intended to be run on. Despite they cannot be loaded there (or even
148 when they load they cannot be used due to missing HW support),
149 developers still, opposing to distributors, might want to build such
150 drivers to compile-test them.
151
152 If you are a developer and want to build everything available, say Y
153 here. If you are a user/distributor, say N here to exclude useless
154 drivers to be distributed.
155
Linus Torvalds3fe617c2021-09-05 11:24:05 -0700156config WERROR
157 bool "Compile the kernel with warnings as errors"
Marco Elverb339ec92021-09-07 23:12:08 +0200158 default COMPILE_TEST
Linus Torvalds3fe617c2021-09-05 11:24:05 -0700159 help
160 A kernel build should not cause any compiler warnings, and this
Miguel Ojeda2f7ab122021-07-03 16:42:57 +0200161 enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
Xin Lie1789d72022-10-25 00:30:23 -0700162 to enforce that rule by default. Certain warnings from other tools
163 such as the linker may be upgraded to errors with this option as
164 well.
Linus Torvalds3fe617c2021-09-05 11:24:05 -0700165
Xin Lie1789d72022-10-25 00:30:23 -0700166 However, if you have a new (or very old) compiler or linker with odd
167 and unusual warnings, or you have some architecture with problems,
Linus Torvalds3fe617c2021-09-05 11:24:05 -0700168 you may need to disable this config option in order to
169 successfully build the kernel.
170
171 If in doubt, say Y.
172
Masahiro Yamadad6fc9fc2019-07-01 09:58:40 +0900173config UAPI_HEADER_TEST
174 bool "Compile test UAPI headers"
Masahiro Yamadafcbb8462019-11-07 16:14:40 +0900175 depends on HEADERS_INSTALL && CC_CAN_LINK
Masahiro Yamadad6fc9fc2019-07-01 09:58:40 +0900176 help
177 Compile test headers exported to user-space to ensure they are
178 self-contained, i.e. compilable as standalone units.
179
180 If you are a developer or tester and want to ensure the exported
181 headers are self-contained, say Y here. Otherwise, choose N.
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183config LOCALVERSION
184 string "Local version - append to kernel release"
185 help
186 Append an extra string to the end of your kernel version.
187 This will show up when you type uname, for example.
188 The string you set here will be appended after the contents of
189 any files with a filename matching localversion* in your
190 object and source tree, in that order. Your total string can
191 be a maximum of 64 characters.
192
Ryan Andersonaaebf432005-07-31 04:57:49 -0400193config LOCALVERSION_AUTO
194 bool "Automatically append version information to the version string"
195 default y
Alexey Dobriyanac3339b2016-08-02 14:07:21 -0700196 depends on !COMPILE_TEST
Ryan Andersonaaebf432005-07-31 04:57:49 -0400197 help
198 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200199 release tree by looking for git tags that belong to the current
200 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400201
202 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200203 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400204 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200205 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400206
Rasmus Villemoes0f9c6082023-01-11 10:38:22 +0100207 (The actual string used here is the first 12 characters produced
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200208 by running the command:
209
210 $ git rev-parse --verify HEAD
211
212 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400213
Laura Abbott9afb7192018-07-05 17:49:37 -0700214config BUILD_SALT
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -0800215 string "Build ID Salt"
216 default ""
217 help
218 The build ID is used to link binaries and their debug info. Setting
219 this option will use the value in the calculation of the build id.
220 This is mostly useful for distributions which want to ensure the
221 build is unique between builds. It's safe to leave the default.
Laura Abbott9afb7192018-07-05 17:49:37 -0700222
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800223config HAVE_KERNEL_GZIP
224 bool
225
226config HAVE_KERNEL_BZIP2
227 bool
228
229config HAVE_KERNEL_LZMA
230 bool
231
Lasse Collin3ebe1242011-01-12 17:01:23 -0800232config HAVE_KERNEL_XZ
233 bool
234
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800235config HAVE_KERNEL_LZO
236 bool
237
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700238config HAVE_KERNEL_LZ4
239 bool
240
Nick Terrell48f7ddf2020-07-30 12:08:36 -0700241config HAVE_KERNEL_ZSTD
242 bool
243
Vasily Gorbikf16466a2018-06-12 21:26:35 +0200244config HAVE_KERNEL_UNCOMPRESSED
245 bool
246
Alain Knaff30d65db2009-01-04 22:46:17 +0100247choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800248 prompt "Kernel compression mode"
249 default KERNEL_GZIP
Nick Terrell48f7ddf2020-07-30 12:08:36 -0700250 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800251 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100252 The linux kernel is a kind of self-extracting executable.
253 Several compression algorithms are available, which differ
254 in efficiency, compression and decompression speed.
255 Compression speed is only relevant when building a kernel.
256 Decompression speed is relevant at each boot.
257
258 If you have any problems with bzip2 or lzma compressed
259 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
260 version of this functionality (bzip2 only), for 2.4, was
261 supplied by Christian Ludwig)
262
263 High compression options are mostly useful for users, who
264 are low on disk space (embedded systems), but for whom ram
265 size matters less.
266
267 If in doubt, select 'gzip'
268
269config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800270 bool "Gzip"
271 depends on HAVE_KERNEL_GZIP
272 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800273 The old and tried gzip compression. It provides a good balance
274 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100275
276config KERNEL_BZIP2
277 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800278 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100279 help
280 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700281 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800282 size is about 10% smaller with bzip2, in comparison to gzip.
283 Bzip2 uses a large amount of memory. For modern kernels you
284 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100285
286config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800287 bool "LZMA"
288 depends on HAVE_KERNEL_LZMA
289 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700290 This compression algorithm's ratio is best. Decompression speed
291 is between gzip and bzip2. Compression is slowest.
292 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100293
Lasse Collin3ebe1242011-01-12 17:01:23 -0800294config KERNEL_XZ
295 bool "XZ"
296 depends on HAVE_KERNEL_XZ
297 help
298 XZ uses the LZMA2 algorithm and instruction set specific
299 BCJ filters which can improve compression ratio of executable
300 code. The size of the kernel is about 30% smaller with XZ in
301 comparison to gzip. On architectures for which there is a BCJ
302 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
303 will create a few percent smaller kernel than plain LZMA.
304
305 The speed is about the same as with LZMA: The decompression
306 speed of XZ is better than that of bzip2 but worse than gzip
307 and LZO. Compression is slow.
308
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800309config KERNEL_LZO
310 bool "LZO"
311 depends on HAVE_KERNEL_LZO
312 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700313 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200314 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800315 (both compression and decompression) is the fastest.
316
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700317config KERNEL_LZ4
318 bool "LZ4"
319 depends on HAVE_KERNEL_LZ4
320 help
321 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
322 A preliminary version of LZ4 de/compression tool is available at
323 <https://code.google.com/p/lz4/>.
324
325 Its compression ratio is worse than LZO. The size of the kernel
326 is about 8% bigger than LZO. But the decompression speed is
327 faster than LZO.
328
Nick Terrell48f7ddf2020-07-30 12:08:36 -0700329config KERNEL_ZSTD
330 bool "ZSTD"
331 depends on HAVE_KERNEL_ZSTD
332 help
333 ZSTD is a compression algorithm targeting intermediate compression
334 with fast decompression speed. It will compress better than GZIP and
335 decompress around the same speed as LZO, but slower than LZ4. You
336 will need at least 192 KB RAM or more for booting. The zstd command
337 line tool is required for compression.
338
Vasily Gorbikf16466a2018-06-12 21:26:35 +0200339config KERNEL_UNCOMPRESSED
340 bool "None"
341 depends on HAVE_KERNEL_UNCOMPRESSED
342 help
343 Produce uncompressed kernel image. This option is usually not what
344 you want. It is useful for debugging the kernel in slow simulation
345 environments, where decompressing and moving the kernel is awfully
346 slow. This option allows early boot code to skip the decompressor
347 and jump right at uncompressed kernel image.
348
Alain Knaff30d65db2009-01-04 22:46:17 +0100349endchoice
350
Chris Downada4ab72020-06-04 16:50:53 -0700351config DEFAULT_INIT
352 string "Default init path"
353 default ""
354 help
355 This option determines the default init for the system if no init=
356 option is passed on the kernel command line. If the requested path is
357 not present, we will still then move on to attempting further
358 locations (e.g. /sbin/init, etc). If this is empty, we will just use
359 the fallback list when init= is not passed.
360
Josh Triplettbd5dc172011-06-15 15:08:28 -0700361config DEFAULT_HOSTNAME
362 string "Default hostname"
363 default "(none)"
364 help
365 This option determines the default system hostname before userspace
366 calls sethostname(2). The kernel traditionally uses "(none)" here,
367 but you may wish to use a different default here to make a minimal
368 system more usable with less configuration.
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370config SYSVIPC
371 bool "System V IPC"
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900372 help
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 Inter Process Communication is a suite of library functions and
374 system calls which let processes (running programs) synchronize and
375 exchange information. It is generally considered to be a good thing,
376 and some programs won't run unless you say Y here. In particular, if
377 you want to run the DOS emulator dosemu under Linux (read the
378 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
379 you'll need to say Y here.
380
381 You can find documentation about IPC with "info ipc" and also in
382 section 6.4 of the Linux Programmer's Guide, available from
383 <http://www.tldp.org/guides.html>.
384
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800385config SYSVIPC_SYSCTL
386 bool
387 depends on SYSVIPC
388 depends on SYSCTL
389 default y
390
Guo Ren0cbed0e2022-04-05 15:12:58 +0800391config SYSVIPC_COMPAT
392 def_bool y
393 depends on COMPAT && SYSVIPC
394
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395config POSIX_MQUEUE
396 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700397 depends on NET
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900398 help
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 POSIX variant of message queues is a part of IPC. In POSIX message
400 queues every message has a priority which decides about succession
401 of receiving it by a process. If you want to compile and run
402 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e376502007-05-09 07:25:13 +0200403 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404
405 POSIX message queues are visible as a filesystem called 'mqueue'
406 and can be mounted somewhere if you want to do filesystem
407 operations on message queues.
408
409 If unsure, say Y.
410
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700411config POSIX_MQUEUE_SYSCTL
412 bool
413 depends on POSIX_MQUEUE
414 depends on SYSCTL
415 default y
416
David Howellsc73be612020-01-14 17:07:11 +0000417config WATCH_QUEUE
418 bool "General notification queue"
419 default n
420 help
421
422 This is a general notification queue for the kernel to pass events to
423 userspace by splicing them into pipes. It can be used in conjunction
424 with watches for key/keyring change notifications and device
425 notifications.
426
Mauro Carvalho Chehabc02b8722022-06-26 10:10:56 +0100427 See Documentation/core-api/watch_queue.rst
David Howellsc73be612020-01-14 17:07:11 +0000428
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700429config CROSS_MEMORY_ATTACH
430 bool "Enable process_vm_readv/writev syscalls"
431 depends on MMU
432 default y
433 help
434 Enabling this option adds the system calls process_vm_readv and
435 process_vm_writev which allow a process with the correct privileges
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700436 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700437 See the man page for more details.
438
Josh Triplett69369a72014-04-03 14:48:27 -0700439config USELIB
Kees Cook7374fa32022-04-29 14:38:01 -0700440 bool "uselib syscall (for libc5 and earlier)"
441 default ALPHA || M68K || SPARC
Josh Triplett69369a72014-04-03 14:48:27 -0700442 help
443 This option enables the uselib syscall, a system call used in the
444 dynamic linker from libc5 and earlier. glibc does not use this
445 system call. If you intend to run programs built on libc5 or
446 earlier, you may need to enable this syscall. Current systems
447 running glibc can safely disable this.
448
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449config AUDIT
450 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100451 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 help
453 Enable auditing infrastructure that can be used with another
454 kernel subsystem, such as SELinux (which requires this for
Paul Moorecb74ed22016-01-13 09:18:55 -0500455 logging of avc messages output). System call auditing is included
456 on architectures which support it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900458config HAVE_ARCH_AUDITSYSCALL
459 bool
460
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461config AUDITSYSCALL
Paul Moorecb74ed22016-01-13 09:18:55 -0500462 def_bool y
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900463 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500464 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400465
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000466source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200467source "kernel/time/Kconfig"
Daniel Borkmannb24abcf2021-05-11 22:35:16 +0200468source "kernel/bpf/Kconfig"
Christoph Hellwig87a4c372018-07-31 13:39:32 +0200469source "kernel/Kconfig.preempt"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000470
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200471menu "CPU/Task time and stats accounting"
472
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200473config VIRT_CPU_ACCOUNTING
474 bool
475
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200476choice
477 prompt "Cputime accounting"
Nicholas Piggin02382af2022-09-02 18:53:15 +1000478 default TICK_CPU_ACCOUNTING
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200479
480# Kind of a stub config for the pure tick based cputime accounting
481config TICK_CPU_ACCOUNTING
482 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200483 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200484 help
485 This is the basic tick based cputime accounting that maintains
486 statistics about user, system and idle time spent on per jiffies
487 granularity.
488
489 If unsure, say Y.
490
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200491config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200492 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200493 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200494 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200495 help
496 Select this option to enable more accurate task and CPU time
497 accounting. This is done by reading a CPU counter on each
498 kernel entry and exit and on transitions within the kernel
499 between system, softirq and hardirq state, so there is a
500 small performance impact. In the case of s390 or IBM POWER > 5,
501 this also enables accounting of stolen time on logically-partitioned
502 systems.
503
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200504config VIRT_CPU_ACCOUNTING_GEN
505 bool "Full dynticks CPU time accounting"
Frederic Weisbecker24a9c5412022-06-08 16:40:24 +0200506 depends on HAVE_CONTEXT_TRACKING_USER
Kevin Hilman554b0002013-09-16 15:28:21 -0700507 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Arnd Bergmann041a1572019-03-04 21:01:31 +0100508 depends on GENERIC_CLOCKEVENTS
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200509 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker24a9c5412022-06-08 16:40:24 +0200510 select CONTEXT_TRACKING_USER
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200511 help
512 Select this option to enable task and CPU time accounting on full
513 dynticks systems. This accounting is implemented by watching every
514 kernel-user boundaries using the context tracking subsystem.
515 The accounting is thus performed at the expense of some significant
516 overhead.
517
518 For now this is only useful if you are working on the full
519 dynticks subsystem development.
520
521 If unsure, say N.
522
Rik van Rielb58c3582016-07-13 16:50:02 +0200523endchoice
524
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200525config IRQ_TIME_ACCOUNTING
526 bool "Fine granularity task level IRQ time accounting"
Rik van Rielb58c3582016-07-13 16:50:02 +0200527 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200528 help
529 Select this option to enable fine granularity task irq time
530 accounting. This is done by reading a timestamp on each
531 transitions between softirq and hardirq state, so there can be a
532 small performance impact.
533
534 If in doubt, say N here.
535
Vincent Guittot11d4afd2018-09-25 11:17:42 +0200536config HAVE_SCHED_AVG_IRQ
537 def_bool y
538 depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
539 depends on SMP
540
Thara Gopinath76504792020-02-21 19:52:05 -0500541config SCHED_THERMAL_PRESSURE
Valentin Schneider98eb4012020-07-12 17:59:16 +0100542 bool
Valentin Schneiderfcd7c9c2020-07-29 14:57:18 +0100543 default y if ARM && ARM_CPU_TOPOLOGY
544 default y if ARM64
Thara Gopinath76504792020-02-21 19:52:05 -0500545 depends on SMP
Valentin Schneider98eb4012020-07-12 17:59:16 +0100546 depends on CPU_FREQ_THERMAL
547 help
548 Select this option to enable thermal pressure accounting in the
549 scheduler. Thermal pressure is the value conveyed to the scheduler
550 that reflects the reduction in CPU compute capacity resulted from
551 thermal throttling. Thermal throttling occurs when the performance of
552 a CPU is capped due to high operating temperatures.
553
554 If selected, the scheduler will be able to balance tasks accordingly,
555 i.e. put less load on throttled CPUs than on non/less throttled ones.
556
557 This requires the architecture to implement
Lukasz Luba7e97b3d2021-11-09 19:57:14 +0000558 arch_update_thermal_pressure() and arch_scale_thermal_pressure().
Thara Gopinath76504792020-02-21 19:52:05 -0500559
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200560config BSD_PROCESS_ACCT
561 bool "BSD Process Accounting"
Iulia Manda28138932015-04-15 16:16:41 -0700562 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200563 help
564 If you say Y here, a user level program will be able to instruct the
565 kernel (via a special system call) to write process accounting
566 information to a file: whenever a process exits, information about
567 that process will be appended to the file by the kernel. The
568 information includes things such as creation time, owning user,
569 command name, memory usage, controlling terminal etc. (the complete
570 list is in the struct acct in <file:include/linux/acct.h>). It is
571 up to the user level program to do useful things with this
572 information. This is generally a good idea, so say Y.
573
574config BSD_PROCESS_ACCT_V3
575 bool "BSD Process Accounting version 3 file format"
576 depends on BSD_PROCESS_ACCT
577 default n
578 help
579 If you say Y here, the process accounting information is written
580 in a new file format that also logs the process IDs of each
Randy Dunlap3903bf92018-08-21 21:58:34 -0700581 process and its parent. Note that this file format is incompatible
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200582 with previous v0/v1/v2 file formats, so you will need updated tools
583 for processing it. A preliminary version of these tools is available
584 at <http://www.gnu.org/software/acct/>.
585
586config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700587 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200588 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700589 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200590 default n
591 help
592 Export selected statistics for tasks/processes through the
593 generic netlink interface. Unlike BSD process accounting, the
594 statistics are available during the lifetime of tasks/processes as
595 responses to commands. Like BSD accounting, they are sent to user
596 space on task exit.
597
598 Say N if unsure.
599
600config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700601 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200602 depends on TASKSTATS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530603 select SCHED_INFO
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200604 help
605 Collect information on time spent by a task waiting for system
606 resources like cpu, synchronous block I/O completion and swapping
607 in pages. Such statistics can help in setting a task's priorities
608 relative to other tasks for cpu, io, rss limits etc.
609
610 Say N if unsure.
611
612config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700613 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200614 depends on TASKSTATS
615 help
616 Collect extended task accounting data and send the data
617 to userland for processing over the taskstats interface.
618
619 Say N if unsure.
620
621config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700622 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200623 depends on TASK_XACCT
624 help
625 Collect information on the number of bytes of storage I/O which this
626 task has caused.
627
628 Say N if unsure.
629
Johannes Weinereb414682018-10-26 15:06:27 -0700630config PSI
631 bool "Pressure stall information tracking"
Randy Dunlap98dfdd92023-07-30 20:07:40 -0700632 select KERNFS
Johannes Weinereb414682018-10-26 15:06:27 -0700633 help
634 Collect metrics that indicate how overcommitted the CPU, memory,
635 and IO capacity are in the system.
636
637 If you say Y here, the kernel will create /proc/pressure/ with the
638 pressure statistics files cpu, memory, and io. These will indicate
639 the share of walltime in which some or all tasks in the system are
640 delayed due to contention of the respective resource.
641
Johannes Weiner2ce71352018-10-26 15:06:31 -0700642 In kernels with cgroup support, cgroups (cgroup2 only) will
643 have cpu.pressure, memory.pressure, and io.pressure files,
644 which aggregate pressure stalls for the grouped tasks only.
645
Mauro Carvalho Chehabc3123552019-04-17 05:46:08 -0300646 For more details see Documentation/accounting/psi.rst.
Johannes Weinereb414682018-10-26 15:06:27 -0700647
648 Say N if unsure.
649
Johannes Weinere0c27442018-11-30 14:09:58 -0800650config PSI_DEFAULT_DISABLED
651 bool "Require boot parameter to enable pressure stall information tracking"
652 default n
653 depends on PSI
654 help
655 If set, pressure stall information tracking will be disabled
Baruch Siach428a1cb2018-12-14 14:17:03 -0800656 per default but can be enabled through passing psi=1 on the
657 kernel commandline during boot.
Johannes Weinere0c27442018-11-30 14:09:58 -0800658
Johannes Weiner7b2489d2019-02-01 14:21:15 -0800659 This feature adds some code to the task wakeup and sleep
660 paths of the scheduler. The overhead is too low to affect
661 common scheduling-intense workloads in practice (such as
662 webservers, memcache), but it does show up in artificial
663 scheduler stress tests, such as hackbench.
664
665 If you are paranoid and not sure what the kernel will be
666 used for, say Y.
667
668 Say N if unsure.
669
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200670endmenu # "CPU/Task time and stats accounting"
671
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200672config CPU_ISOLATION
673 bool "CPU isolation"
Geert Uytterhoeven414a2dc2018-01-02 12:13:10 +0100674 depends on SMP || COMPILE_TEST
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100675 default y
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200676 help
677 Make sure that CPUs running critical tasks are not disturbed by
678 any source of "noise" such as unbound workqueues, timers, kthreads...
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100679 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
680 the "isolcpus=" boot parameter.
681
682 Say Y if unsure.
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200683
Paul E. McKenney0af92d42017-05-17 08:43:40 -0700684source "kernel/rcu/Kconfig"
Mike Travisc903ff82009-01-15 12:28:29 -0800685
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700687 tristate "Kernel .config support"
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900688 help
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 This option enables the complete Linux kernel ".config" file
690 contents to be saved in the kernel. It provides documentation
691 of which kernel options are used in a running kernel or in an
692 on-disk kernel. This information can be extracted from the kernel
693 image file with the script scripts/extract-ikconfig and used as
694 input to rebuild the current kernel or to build another kernel.
695 It can also be extracted from a running kernel by reading
696 /proc/config.gz if enabled (below).
697
698config IKCONFIG_PROC
699 bool "Enable access to .config through /proc/config.gz"
700 depends on IKCONFIG && PROC_FS
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900701 help
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 This option enables access to the kernel configuration file
703 through /proc/config.gz.
704
Joel Fernandes (Google)f7b101d2019-05-15 17:35:51 -0400705config IKHEADERS
706 tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
707 depends on SYSFS
Joel Fernandes (Google)43d8ce92019-04-26 15:04:29 -0400708 help
Joel Fernandes (Google)f7b101d2019-05-15 17:35:51 -0400709 This option enables access to the in-kernel headers that are generated during
710 the build process. These can be used to build eBPF tracing programs,
711 or similar programs. If you build the headers as a module, a module called
712 kheaders.ko is built which can be loaded on-demand to get access to headers.
Joel Fernandes (Google)43d8ce92019-04-26 15:04:29 -0400713
Alistair John Strachan794543a2007-05-08 00:31:15 -0700714config LOG_BUF_SHIFT
715 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Christoph Hellwig1c4b5ec2022-02-23 08:47:20 +0100716 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700717 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700718 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700719 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700720 Select the minimal kernel log buffer size as a power of 2.
721 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
722 parameter, see below. Any higher size also might be forced
723 by "log_buf_len" boot parameter.
724
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700725 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700726 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700727 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700728 15 => 32 KB
729 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700730 13 => 8 KB
731 12 => 4 KB
732
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700733config LOG_CPU_MAX_BUF_SHIFT
734 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700735 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700736 range 0 21
737 default 12 if !BASE_SMALL
738 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700739 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700740 help
741 This option allows to increase the default ring buffer size
742 according to the number of CPUs. The value defines the contribution
743 of each CPU as a power of 2. The used space is typically only few
744 lines however it might be much more when problems are reported,
745 e.g. backtraces.
746
747 The increased size means that a new buffer has to be allocated and
748 the original static one is unused. It makes sense only on systems
749 with more CPUs. Therefore this value is used only when the sum of
750 contributions is greater than the half of the default kernel ring
751 buffer as defined by LOG_BUF_SHIFT. The default values are set
Paul Menzel0f7636e12020-08-11 11:29:23 +0200752 so that more than 16 CPUs are needed to trigger the allocation.
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700753
754 Also this option is ignored when "log_buf_len" kernel parameter is
755 used as it forces an exact (power of two) size of the ring buffer.
756
757 The number of possible CPUs is used for this computation ignoring
Geert Uytterhoeven5e0d8d52016-06-05 10:47:02 +0200758 hotplugging making the computation optimal for the worst case
759 scenario while allowing a simple algorithm to be used from bootup.
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700760
761 Examples shift values and their meaning:
762 17 => 128 KB for each CPU
763 16 => 64 KB for each CPU
764 15 => 32 KB for each CPU
765 14 => 16 KB for each CPU
766 13 => 8 KB for each CPU
767 12 => 4 KB for each CPU
768
Chris Down33701552021-06-15 17:52:53 +0100769config PRINTK_INDEX
770 bool "Printk indexing debugfs interface"
771 depends on PRINTK && DEBUG_FS
772 help
773 Add support for indexing of all printk formats known at compile time
774 at <debugfs>/printk/index/<module>.
775
776 This can be used as part of maintaining daemons which monitor
777 /dev/kmsg, as it permits auditing the printk formats present in a
778 kernel, allowing detection of cases where monitored printks are
779 changed or no longer present.
780
781 There is no additional runtime cost to printk with this enabled.
782
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800783#
784# Architectures with an unreliable sched_clock() should select this:
785#
786config HAVE_UNSTABLE_SCHED_CLOCK
787 bool
788
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700789config GENERIC_SCHED_CLOCK
790 bool
791
Patrick Bellasi69842cb2019-06-21 09:42:02 +0100792menu "Scheduler features"
793
794config UCLAMP_TASK
795 bool "Enable utilization clamping for RT/FAIR tasks"
796 depends on CPU_FREQ_GOV_SCHEDUTIL
797 help
798 This feature enables the scheduler to track the clamped utilization
799 of each CPU based on RUNNABLE tasks scheduled on that CPU.
800
801 With this option, the user can specify the min and max CPU
802 utilization allowed for RUNNABLE tasks. The max utilization defines
803 the maximum frequency a task should use while the min utilization
804 defines the minimum frequency it should use.
805
806 Both min and max utilization clamp values are hints to the scheduler,
807 aiming at improving its frequency selection policy, but they do not
808 enforce or grant any specific bandwidth for tasks.
809
810 If in doubt, say N.
811
812config UCLAMP_BUCKETS_COUNT
813 int "Number of supported utilization clamp buckets"
814 range 5 20
815 default 5
816 depends on UCLAMP_TASK
817 help
818 Defines the number of clamp buckets to use. The range of each bucket
819 will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the
820 number of clamp buckets the finer their granularity and the higher
821 the precision of clamping aggregation and tracking at run-time.
822
823 For example, with the minimum configuration value we will have 5
824 clamp buckets tracking 20% utilization each. A 25% boosted tasks will
825 be refcounted in the [20..39]% bucket and will set the bucket clamp
826 effective value to 25%.
827 If a second 30% boosted task should be co-scheduled on the same CPU,
828 that task will be refcounted in the same bucket of the first task and
829 it will boost the bucket clamp effective value to 30%.
830 The clamp effective value of a bucket is reset to its nominal value
831 (20% in the example above) when there are no more tasks refcounted in
832 that bucket.
833
834 An additional boost/capping margin can be added to some tasks. In the
835 example above the 25% task will be boosted to 30% until it exits the
836 CPU. If that should be considered not acceptable on certain systems,
837 it's always possible to reduce the margin by increasing the number of
838 clamp buckets to trade off used memory for run-time tracking
839 precision.
840
841 If in doubt, use the default value.
842
843endmenu
844
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200845#
846# For architectures that want to enable the support for NUMA-affine scheduler
847# balancing logic:
848#
849config ARCH_SUPPORTS_NUMA_BALANCING
850 bool
851
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100852#
Mel Gorman72b252a2015-09-04 15:47:32 -0700853# For architectures that prefer to flush all TLBs after a number of pages
854# are unmapped instead of sending one IPI per page to flush. The architecture
855# must provide guarantees on what happens if a clean TLB cache entry is
856# written after the unmap. Details are in mm/rmap.c near the check for
857# should_defer_flush. The architecture should also consider if the full flush
858# and the refill costs are offset by the savings of sending fewer IPIs.
859config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
860 bool
861
Ard Biesheuvelc12d3362019-11-08 13:22:27 +0100862config CC_HAS_INT128
Masahiro Yamada3a7c7332020-03-10 19:12:50 +0900863 def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
Ard Biesheuvelc12d3362019-11-08 13:22:27 +0100864
Gustavo A. R. Silvadee2b7022021-11-13 18:57:25 -0600865config CC_IMPLICIT_FALLTHROUGH
866 string
Gustavo A. R. Silva158ea2d2021-11-14 20:48:44 -0600867 default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
Gustavo A. R. Silvadee2b7022021-11-13 18:57:25 -0600868 default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)
869
Linus Torvalds0da6e5f2023-04-23 09:56:20 -0700870# Currently, disable gcc-11+ array-bounds globally.
871# It's still broken in gcc-13, so no upper bound yet.
Linus Torvalds5a412372023-01-09 17:04:49 -0600872config GCC11_NO_ARRAY_BOUNDS
873 def_bool y
874
Linus Torvaldsf0be87c2022-06-09 10:11:12 -0700875config CC_NO_ARRAY_BOUNDS
876 bool
Linus Torvalds0da6e5f2023-04-23 09:56:20 -0700877 default y if CC_IS_GCC && GCC_VERSION >= 110000 && GCC11_NO_ARRAY_BOUNDS
Linus Torvaldsf0be87c2022-06-09 10:11:12 -0700878
Mel Gorman72b252a2015-09-04 15:47:32 -0700879#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100880# For architectures that know their GCC __int128 support is sound
881#
882config ARCH_SUPPORTS_INT128
883 bool
884
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200885# For architectures that (ab)use NUMA to represent different memory regions
886# all cpu-local but of different latencies, such as SuperH.
887#
888config ARCH_WANT_NUMA_VARIABLE_LOCALITY
889 bool
890
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200891config NUMA_BALANCING
892 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200893 depends on ARCH_SUPPORTS_NUMA_BALANCING
894 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
Sebastian Andrzej Siewior554b0f32021-11-05 13:35:27 -0700895 depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200896 help
897 This option adds support for automatic NUMA aware memory/task placement.
898 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400899 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200900
901 This system will be inactive on UMA systems.
902
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800903config NUMA_BALANCING_DEFAULT_ENABLED
904 bool "Automatically enable NUMA aware memory/task placement"
905 default y
906 depends on NUMA_BALANCING
907 help
908 If set, automatic NUMA balancing will be enabled if running on a NUMA
909 machine.
910
Li Zefan23964d22009-01-15 13:50:58 -0800911menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500912 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500913 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700914 help
Li Zefan23964d22009-01-15 13:50:58 -0800915 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800916 use with process control subsystems such as Cpusets, CFS, memory
917 controls or device isolation.
918 See
Mauro Carvalho Chehabd6a3b242019-06-12 14:53:03 -0300919 - Documentation/scheduler/sched-design-CFS.rst (CFS)
Mauro Carvalho Chehabda82c922019-06-27 13:08:35 -0300920 - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation
Li Zefan45ce80f2009-01-15 13:50:59 -0800921 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700922
923 Say N if unsure.
924
Li Zefan23964d22009-01-15 13:50:58 -0800925if CGROUPS
926
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800927config PAGE_COUNTER
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -0800928 bool
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800929
Tejun Heo6a010a42022-07-23 04:28:28 -1000930config CGROUP_FAVOR_DYNMODS
931 bool "Favor dynamic modification latency reduction by default"
932 help
933 This option enables the "favordynmods" mount option by default
934 which reduces the latencies of dynamic cgroup modifications such
935 as task migrations and controller on/offs at the cost of making
936 hot path operations such as forks and exits more expensive.
937
938 Say N if unsure.
939
Andrew Mortonc255a452012-07-31 16:43:02 -0700940config MEMCG
Johannes Weinera0166ec2015-12-17 17:19:56 -0500941 bool "Memory controller"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800942 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500943 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800944 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500945 Provides control over the memory footprint of tasks in a cgroup.
Balbir Singh00f0b822008-03-04 14:28:39 -0800946
Kirill Tkhai84c07d12018-08-17 15:47:25 -0700947config MEMCG_KMEM
948 bool
Vlastimil Babkac9929f02023-02-27 17:46:13 +0100949 depends on MEMCG
Kirill Tkhai84c07d12018-08-17 15:47:25 -0700950 default y
951
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500952config BLK_CGROUP
953 bool "IO controller"
954 depends on BLOCK
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700955 default n
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +0900956 help
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500957 Generic block IO controller cgroup interface. This is the common
958 cgroup interface which should be used by various IO controlling
959 policies.
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700960
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500961 Currently, CFQ IO scheduler uses it to recognize task groups and
962 control disk bandwidth allocation (proportional time slice allocation)
963 to such task groups. It is also used by bio throttling logic in
964 block layer to implement upper limit in IO rates on a device.
Stephane Eraniane5d13672011-02-14 11:20:01 +0200965
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500966 This option only enables generic Block IO controller infrastructure.
967 One needs to also enable actual IO controlling logic/policy. For
968 enabling proportional weight division of disk bandwidth in CFQ, set
Krzysztof Kozlowski7baf2192020-04-06 20:12:02 -0700969 CONFIG_BFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500970 CONFIG_BLK_DEV_THROTTLING=y.
971
Mauro Carvalho Chehabda82c922019-06-27 13:08:35 -0300972 See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500973
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500974config CGROUP_WRITEBACK
975 bool
976 depends on MEMCG && BLK_CGROUP
977 default y
Stephane Eraniane5d13672011-02-14 11:20:01 +0200978
Dhaval Giani7c941432010-01-20 13:26:18 +0100979menuconfig CGROUP_SCHED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500980 bool "CPU controller"
Dhaval Giani7c941432010-01-20 13:26:18 +0100981 default n
982 help
983 This feature lets CPU scheduler recognize task groups and control CPU
984 bandwidth allocation to such task groups. It uses cgroups to group
985 tasks.
986
987if CGROUP_SCHED
988config FAIR_GROUP_SCHED
989 bool "Group scheduling for SCHED_OTHER"
990 depends on CGROUP_SCHED
991 default CGROUP_SCHED
992
Paul Turnerab84d312011-07-21 09:43:28 -0700993config CFS_BANDWIDTH
994 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -0700995 depends on FAIR_GROUP_SCHED
996 default n
997 help
998 This option allows users to define CPU bandwidth rates (limits) for
999 tasks running within the fair group scheduler. Groups with no limit
1000 set are considered to be unconstrained and will run with no
1001 restriction.
Mauro Carvalho Chehabd6a3b242019-06-12 14:53:03 -03001002 See Documentation/scheduler/sched-bwc.rst for more information.
Paul Turnerab84d312011-07-21 09:43:28 -07001003
Dhaval Giani7c941432010-01-20 13:26:18 +01001004config RT_GROUP_SCHED
1005 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001006 depends on CGROUP_SCHED
1007 default n
1008 help
1009 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001010 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001011 schedule realtime tasks for non-root users until you allocate
1012 realtime bandwidth for them.
Mauro Carvalho Chehabd6a3b242019-06-12 14:53:03 -03001013 See Documentation/scheduler/sched-rt-group.rst for more information.
Dhaval Giani7c941432010-01-20 13:26:18 +01001014
1015endif #CGROUP_SCHED
1016
Mathieu Desnoyersaf7f5882022-11-22 15:39:09 -05001017config SCHED_MM_CID
1018 def_bool y
1019 depends on SMP && RSEQ
1020
Patrick Bellasi2480c092019-08-22 14:28:06 +01001021config UCLAMP_TASK_GROUP
1022 bool "Utilization clamping per group of tasks"
1023 depends on CGROUP_SCHED
1024 depends on UCLAMP_TASK
1025 default n
1026 help
1027 This feature enables the scheduler to track the clamped utilization
1028 of each CPU based on RUNNABLE tasks currently scheduled on that CPU.
1029
1030 When this option is enabled, the user can specify a min and max
1031 CPU bandwidth which is allowed for each single task in a group.
1032 The max bandwidth allows to clamp the maximum frequency a task
1033 can use, while the min bandwidth allows to define a minimum
1034 frequency a task will always use.
1035
1036 When task group based utilization clamping is enabled, an eventually
1037 specified task-specific clamp value is constrained by the cgroup
1038 specified clamp value. Both minimum and maximum task clamping cannot
1039 be bigger than the corresponding clamping defined at task group level.
1040
1041 If in doubt, say N.
1042
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001043config CGROUP_PIDS
1044 bool "PIDs controller"
1045 help
1046 Provides enforcement of process number limits in the scope of a
1047 cgroup. Any attempt to fork more processes than is allowed in the
1048 cgroup will fail. PIDs are fundamentally a global resource because it
1049 is fairly trivial to reach PID exhaustion before you reach even a
1050 conservative kmemcg limit. As a result, it is possible to grind a
1051 system to halt without being limited by other cgroup policies. The
Parav Pandit6cc578d2016-03-05 11:30:56 +05301052 PIDs controller is designed to stop this from happening.
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001053
1054 It should be noted that organisational operations (such as attaching
Jonathan Neuschäfer98076832019-02-01 14:21:01 -08001055 to a cgroup hierarchy) will *not* be blocked by the PIDs controller,
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001056 since the PIDs limit only affects a process's ability to fork, not to
1057 attach to a cgroup.
1058
Parav Pandit39d3e752017-01-10 00:02:13 +00001059config CGROUP_RDMA
1060 bool "RDMA controller"
1061 help
1062 Provides enforcement of RDMA resources defined by IB stack.
1063 It is fairly easy for consumers to exhaust RDMA resources, which
1064 can result into resource unavailability to other consumers.
1065 RDMA controller is designed to stop this from happening.
1066 Attaching processes with active RDMA resources to the cgroup
1067 hierarchy is allowed even if can cross the hierarchy's limit.
1068
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001069config CGROUP_FREEZER
1070 bool "Freezer controller"
1071 help
1072 Provides a way to freeze and unfreeze all tasks in a
1073 cgroup.
1074
Johannes Weiner489c2a22016-01-20 15:02:41 -08001075 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1076 controller includes important in-kernel memory consumers per default.
1077
1078 If you're using cgroup2, say N.
1079
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001080config CGROUP_HUGETLB
1081 bool "HugeTLB controller"
1082 depends on HUGETLB_PAGE
1083 select PAGE_COUNTER
Vivek Goyalafc24d42010-04-26 19:27:56 +02001084 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001085 help
1086 Provides a cgroup controller for HugeTLB pages.
1087 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1088 The limit is enforced during page fault. Since HugeTLB doesn't
1089 support page reclaim, enforcing the limit at page fault time implies
1090 that, the application will get SIGBUS signal if it tries to access
1091 HugeTLB pages beyond its limit. This requires the application to know
1092 beforehand how much HugeTLB pages it would require for its use. The
1093 control group is tracked in the third page lru pointer. This means
1094 that we cannot use the controller with huge page less than 3 pages.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001095
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001096config CPUSETS
1097 bool "Cpuset controller"
Nicolas Pitree1d4eee2017-06-14 13:19:23 -04001098 depends on SMP
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001099 help
1100 This option will let you create and manage CPUSETs which
1101 allow dynamically partitioning a system into sets of CPUs and
1102 Memory Nodes and assigning tasks to run only within those sets.
1103 This is primarily useful on large SMP or NUMA systems.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001104
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001105 Say N if unsure.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001106
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001107config PROC_PID_CPUSET
1108 bool "Include legacy /proc/<pid>/cpuset file"
1109 depends on CPUSETS
Tejun Heo89e9b9e2015-05-22 17:13:36 -04001110 default y
1111
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001112config CGROUP_DEVICE
1113 bool "Device controller"
1114 help
1115 Provides a cgroup controller implementing whitelists for
1116 devices which a process in the cgroup can mknod or open.
1117
1118config CGROUP_CPUACCT
1119 bool "Simple CPU accounting controller"
1120 help
1121 Provides a simple controller for monitoring the
1122 total CPU consumed by the tasks in a cgroup.
1123
1124config CGROUP_PERF
1125 bool "Perf controller"
1126 depends on PERF_EVENTS
1127 help
1128 This option extends the perf per-cpu mode to restrict monitoring
1129 to threads which belong to the cgroup specified and run on the
Namhyung Kim6546b192020-03-25 21:45:29 +09001130 designated cpu. Or this can be used to have cgroup ID in samples
1131 so that it can monitor performance events among cgroups.
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001132
1133 Say N if unsure.
1134
Daniel Mack30070982016-11-23 16:52:26 +01001135config CGROUP_BPF
1136 bool "Support for eBPF programs attached to cgroups"
Andy Lutomirski483c4932016-12-16 08:33:45 -08001137 depends on BPF_SYSCALL
1138 select SOCK_CGROUP_DATA
Daniel Mack30070982016-11-23 16:52:26 +01001139 help
1140 Allow attaching eBPF programs to a cgroup using the bpf(2)
1141 syscall command BPF_PROG_ATTACH.
1142
1143 In which context these programs are accessed depends on the type
1144 of attachment. For instance, programs that are attached using
1145 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
1146 inet sockets.
1147
Vipin Sharmaa72232e2021-03-29 21:42:04 -07001148config CGROUP_MISC
1149 bool "Misc resource controller"
1150 default n
1151 help
1152 Provides a controller for miscellaneous resources on a host.
1153
1154 Miscellaneous scalar resources are the resources on the host system
1155 which cannot be abstracted like the other cgroups. This controller
1156 tracks and limits the miscellaneous resources used by a process
1157 attached to a cgroup hierarchy.
1158
1159 For more information, please check misc cgroup section in
1160 /Documentation/admin-guide/cgroup-v2.rst.
1161
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001162config CGROUP_DEBUG
Waiman Long23b0be42017-06-13 17:18:03 -04001163 bool "Debug controller"
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001164 default n
Waiman Long23b0be42017-06-13 17:18:03 -04001165 depends on DEBUG_KERNEL
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001166 help
1167 This option enables a simple controller that exports
Waiman Long23b0be42017-06-13 17:18:03 -04001168 debugging information about the cgroups framework. This
1169 controller is for control cgroup debugging only. Its
1170 interfaces are not stable.
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001171
1172 Say N.
1173
Arnd Bergmann73b35142017-01-10 13:08:06 +01001174config SOCK_CGROUP_DATA
1175 bool
1176 default n
1177
Li Zefan23964d22009-01-15 13:50:58 -08001178endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001179
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001180menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001181 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001182 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001183 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001184 help
1185 Provides the way to make tasks work with different objects using
1186 the same id. For example same IPC id may refer to different objects
1187 or same user id or pid may refer to different tasks when used in
1188 different namespaces.
1189
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001190if NAMESPACES
1191
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001192config UTS_NS
1193 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001194 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001195 help
1196 In this namespace tasks see different info provided with the
1197 uname() system call
1198
Andrei Vagin769071a2019-11-12 01:26:52 +00001199config TIME_NS
1200 bool "TIME namespace"
Thomas Gleixner660fd042019-11-12 01:27:09 +00001201 depends on GENERIC_VDSO_TIME_NS
Andrei Vagin769071a2019-11-12 01:26:52 +00001202 default y
1203 help
1204 In this namespace boottime and monotonic clocks can be set.
1205 The time will keep going with the same pace.
1206
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001207config IPC_NS
1208 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001209 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001210 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001211 help
1212 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001213 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001214
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001215config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001216 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001217 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001218 help
1219 This allows containers, i.e. vservers, to use user namespaces
1220 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001221
1222 When user namespaces are enabled in the kernel it is
Johannes Weinerd886f4e2016-01-20 15:02:47 -08001223 recommended that the MEMCG option also be enabled and that
1224 user-space use the memory control groups to limit the amount
1225 of memory a memory unprivileged users can use.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001226
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001227 If unsure, say N.
1228
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001229config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001230 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001231 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001232 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001233 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001234 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001235 pid namespaces. This is a building block of containers.
1236
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001237config NET_NS
1238 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001239 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001240 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001241 help
1242 Allow user space to create what appear to be multiple instances
1243 of the network stack.
1244
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001245endif # NAMESPACES
1246
Adrian Reber5cb366b2018-08-21 22:01:17 -07001247config CHECKPOINT_RESTORE
1248 bool "Checkpoint/restore support"
Ren Zhijie30341ec2022-09-29 07:00:57 +00001249 depends on PROC_FS
Adrian Reber5cb366b2018-08-21 22:01:17 -07001250 select PROC_CHILDREN
Chris Wilsonbfe39112021-02-05 22:00:12 +00001251 select KCMP
Adrian Reber5cb366b2018-08-21 22:01:17 -07001252 default n
1253 help
1254 Enables additional kernel features in a sake of checkpoint/restore.
1255 In particular it adds auxiliary prctl codes to setup process text,
1256 data and heap segment sizes, and a few additional /proc filesystem
1257 entries.
1258
1259 If unsure, say N here.
1260
Mike Galbraith5091faa2010-11-30 14:18:03 +01001261config SCHED_AUTOGROUP
1262 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001263 select CGROUPS
1264 select CGROUP_SCHED
1265 select FAIR_GROUP_SCHED
1266 help
1267 This option optimizes the scheduler for common desktop workloads by
1268 automatically creating and populating task groups. This separation
1269 of workloads isolates aggressive CPU burners (like build jobs) from
1270 desktop applications. Task group autogeneration is currently based
1271 upon task session.
1272
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001273config RELAY
1274 bool "Kernel->user space relay support (formerly relayfs)"
Peter Zijlstra26b56792016-10-11 13:54:33 -07001275 select IRQ_WORK
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001276 help
1277 This option enables support for relay interface support in
1278 certain file systems (such as debugfs).
1279 It is designed to provide an efficient mechanism for tools and
1280 facilities to relay large amounts of data from kernel space to
1281 user space.
1282
1283 If unsure, say N.
1284
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001285config BLK_DEV_INITRD
1286 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001287 help
1288 The initial RAM filesystem is a ramfs which is loaded by the
1289 boot loader (loadlin or lilo) and that is mounted as root
1290 before the normal boot procedure. It is typically used to
1291 load modules needed to mount the "real" root file system,
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -02001292 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001293
1294 If RAM disk support (BLK_DEV_RAM) is also included, this
1295 also enables initial RAM disk (initrd) support and adds
1296 15 Kbytes (more on some other architectures) to the kernel size.
1297
1298 If unsure say Y.
1299
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001300if BLK_DEV_INITRD
1301
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001302source "usr/Kconfig"
1303
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001304endif
1305
Masami Hiramatsu76db5a22020-01-11 01:03:32 +09001306config BOOT_CONFIG
1307 bool "Boot config support"
Masami Hiramatsua2a9d672022-04-06 11:31:19 +09001308 select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
Masami Hiramatsu76db5a22020-01-11 01:03:32 +09001309 help
1310 Extra boot config allows system admin to pass a config file as
1311 complemental extension of kernel cmdline when booting.
Masami Hiramatsu0947db02020-01-20 12:23:00 +09001312 The boot config file must be attached at the end of initramfs
Masami Hiramatsu85c46b72020-02-20 21:18:42 +09001313 with checksum, size and magic word.
Masami Hiramatsu0947db02020-01-20 12:23:00 +09001314 See <file:Documentation/admin-guide/bootconfig.rst> for details.
Masami Hiramatsu76db5a22020-01-11 01:03:32 +09001315
1316 If unsure, say Y.
1317
Paul E. McKenneyb7438522023-02-22 08:27:48 +09001318config BOOT_CONFIG_FORCE
1319 bool "Force unconditional bootconfig processing"
1320 depends on BOOT_CONFIG
Paul E. McKenney6ded8a22023-02-22 08:27:49 +09001321 default y if BOOT_CONFIG_EMBED
Paul E. McKenneyb7438522023-02-22 08:27:48 +09001322 help
1323 With this Kconfig option set, BOOT_CONFIG processing is carried
1324 out even when the "bootconfig" kernel-boot parameter is omitted.
1325 In fact, with this Kconfig option set, there is no way to
1326 make the kernel ignore the BOOT_CONFIG-supplied kernel-boot
1327 parameters.
1328
1329 If unsure, say N.
1330
Masami Hiramatsua2a9d672022-04-06 11:31:19 +09001331config BOOT_CONFIG_EMBED
1332 bool "Embed bootconfig file in the kernel"
1333 depends on BOOT_CONFIG
1334 help
1335 Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
1336 kernel. Usually, the bootconfig file is loaded with the initrd
1337 image. But if the system doesn't support initrd, this option will
1338 help you by embedding a bootconfig file while building the kernel.
1339
1340 If unsure, say N.
1341
1342config BOOT_CONFIG_EMBED_FILE
1343 string "Embedded bootconfig file path"
1344 depends on BOOT_CONFIG_EMBED
1345 help
1346 Specify a bootconfig file which will be embedded to the kernel.
1347 This bootconfig will be used if there is no initrd or no other
1348 bootconfig in the initrd.
1349
David Disseldorp1274aea12022-05-09 18:29:19 -07001350config INITRAMFS_PRESERVE_MTIME
1351 bool "Preserve cpio archive mtimes in initramfs"
1352 default y
1353 help
1354 Each entry in an initramfs cpio archive carries an mtime value. When
1355 enabled, extracted cpio items take this mtime, with directory mtime
1356 setting deferred until after creation of any child entries.
1357
1358 If unsure, say Y.
1359
Arnd Bergmann877417e2016-04-25 17:35:27 +02001360choice
1361 prompt "Compiler optimization level"
Ulf Magnusson2cc3ce22017-10-04 01:53:26 +02001362 default CC_OPTIMIZE_FOR_PERFORMANCE
Arnd Bergmann877417e2016-04-25 17:35:27 +02001363
1364config CC_OPTIMIZE_FOR_PERFORMANCE
Masahiro Yamada15f5db62019-08-21 02:09:40 +09001365 bool "Optimize for performance (-O2)"
Arnd Bergmann877417e2016-04-25 17:35:27 +02001366 help
1367 This is the default optimization level for the kernel, building
1368 with the "-O2" compiler flag for best performance and most
1369 helpful compile-time warnings.
1370
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001371config CC_OPTIMIZE_FOR_SIZE
Masahiro Yamada15f5db62019-08-21 02:09:40 +09001372 bool "Optimize for size (-Os)"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001373 help
Masahiro Yamadace3b4872019-08-21 02:09:39 +09001374 Choosing this option will pass "-Os" to your compiler resulting
1375 in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001376
Arnd Bergmann877417e2016-04-25 17:35:27 +02001377endchoice
1378
Nicholas Piggin5d20ee32018-05-09 23:00:00 +10001379config HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1380 bool
1381 help
1382 This requires that the arch annotates or otherwise protects
1383 its external entry points from being discarded. Linker scripts
1384 must also merge .text.*, .data.*, and .bss.* correctly into
1385 output sections. Care must be taken not to pull in unrelated
1386 sections (e.g., '.text.init'). Typically '.' in section names
1387 is used to distinguish them from label names / C identifiers.
1388
1389config LD_DEAD_CODE_DATA_ELIMINATION
1390 bool "Dead code and data elimination (EXPERIMENTAL)"
1391 depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
1392 depends on EXPERT
Masahiro Yamadae85d1d62018-08-22 22:51:09 +09001393 depends on $(cc-option,-ffunction-sections -fdata-sections)
1394 depends on $(ld-option,--gc-sections)
Nicholas Piggin5d20ee32018-05-09 23:00:00 +10001395 help
Masahiro Yamada8b9d2712018-06-24 01:41:51 +09001396 Enable this if you want to do dead code and data elimination with
1397 the linker by compiling with -ffunction-sections -fdata-sections,
1398 and linking with --gc-sections.
Nicholas Piggin5d20ee32018-05-09 23:00:00 +10001399
1400 This can reduce on disk and in-memory size of the kernel
1401 code and static data, particularly for small configs and
1402 on small systems. This has the possibility of introducing
1403 silently broken kernel if the required annotations are not
1404 present. This option is not well tested yet, so use at your
1405 own risk.
1406
Nathan Chancellor59612b22020-11-19 13:46:56 -07001407config LD_ORPHAN_WARN
1408 def_bool y
1409 depends on ARCH_WANT_LD_ORPHAN_WARN
1410 depends on $(ld-option,--orphan-handling=warn)
Xin Lie1789d72022-10-25 00:30:23 -07001411 depends on $(ld-option,--orphan-handling=error)
1412
1413config LD_ORPHAN_WARN_LEVEL
1414 string
1415 depends on LD_ORPHAN_WARN
1416 default "error" if WERROR
1417 default "warn"
Nathan Chancellor59612b22020-11-19 13:46:56 -07001418
Randy Dunlap08470622006-09-30 23:28:13 -07001419config SYSCTL
1420 bool
1421
Mike Frysinger657a5202013-04-30 15:28:45 -07001422config HAVE_UID16
1423 bool
1424
1425config SYSCTL_EXCEPTION_TRACE
1426 bool
1427 help
1428 Enable support for /proc/sys/debug/exception-trace.
1429
1430config SYSCTL_ARCH_UNALIGN_NO_WARN
1431 bool
1432 help
1433 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1434 Allows arch to define/use @no_unaligned_warning to possibly warn
1435 about unaligned access emulation going on under the hood.
1436
1437config SYSCTL_ARCH_UNALIGN_ALLOW
1438 bool
1439 help
1440 Enable support for /proc/sys/kernel/unaligned-trap
1441 Allows arches to define/use @unaligned_enabled to runtime toggle
1442 the unaligned access emulation.
1443 see arch/parisc/kernel/unaligned.c for reference
1444
Mike Frysinger657a5202013-04-30 15:28:45 -07001445config HAVE_PCSPKR_PLATFORM
1446 bool
1447
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001448# interpreter that classic socket filters depend on
1449config BPF
1450 bool
Eric Biggersec8f7f42022-07-09 14:18:49 -07001451 select CRYPTO_LIB_SHA1
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001452
David Rientjes6a108a12011-01-20 14:44:16 -08001453menuconfig EXPERT
1454 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001455 # Unhide debug options, to make the on-by-default options visible
1456 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 help
1458 This option allows certain base kernel options and settings
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001459 to be disabled or tweaked. This is for specialized
1460 environments which can tolerate a "non-standard" kernel.
1461 Only use this if you really know what you are doing.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001463config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001464 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001465 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001466 default y
1467 help
1468 This enables the legacy 16-bit UID syscall wrappers.
1469
Iulia Manda28138932015-04-15 16:16:41 -07001470config MULTIUSER
1471 bool "Multiple users, groups and capabilities support" if EXPERT
1472 default y
1473 help
1474 This option enables support for non-root users, groups and
1475 capabilities.
1476
1477 If you say N here, all processes will run with UID 0, GID 0, and all
1478 possible capabilities. Saying N here also compiles out support for
1479 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1480 setgid, and capset.
1481
1482 If unsure, say Y here.
1483
Fabian Frederickf6187762014-06-04 16:11:12 -07001484config SGETMASK_SYSCALL
1485 bool "sgetmask/ssetmask syscalls support" if EXPERT
Arnd Bergmanna687a532018-03-07 23:30:54 +01001486 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +09001487 help
Fabian Frederickf6187762014-06-04 16:11:12 -07001488 sys_sgetmask and sys_ssetmask are obsolete system calls
1489 no longer supported in libc but still enabled by default in some
1490 architectures.
1491
1492 If unsure, leave the default option here.
1493
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001494config SYSFS_SYSCALL
1495 bool "Sysfs syscall support" if EXPERT
1496 default y
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +09001497 help
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001498 sys_sysfs is an obsolete system call no longer supported in libc.
1499 Note that disabling this option is more secure but might break
1500 compatibility with some systems.
1501
1502 If unsure say Y here.
1503
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001504config FHANDLE
1505 bool "open by fhandle syscalls" if EXPERT
1506 select EXPORTFS
1507 default y
1508 help
1509 If you say Y here, a user level program will be able to map
1510 file names to handle and then later use the handle for
1511 different file system operations. This is useful in implementing
1512 userspace file servers, which now track files using handles instead
1513 of names. The handle would remain the same even if file names
1514 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1515 syscalls.
1516
Nicolas Pitrebaa73d92016-11-11 00:10:10 -05001517config POSIX_TIMERS
1518 bool "Posix Clocks & timers" if EXPERT
1519 default y
1520 help
1521 This includes native support for POSIX timers to the kernel.
1522 Some embedded systems have no use for them and therefore they
1523 can be configured out to reduce the size of the kernel image.
1524
1525 When this option is disabled, the following syscalls won't be
1526 available: timer_create, timer_gettime: timer_getoverrun,
1527 timer_settime, timer_delete, clock_adjtime, getitimer,
1528 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1529 clock_getres and clock_nanosleep syscalls will be limited to
1530 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1531
1532 If unsure say y.
1533
Matt Mackalld59745c2005-05-01 08:59:02 -07001534config PRINTK
1535 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001536 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001537 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001538 help
1539 This option enables normal printk support. Removing it
1540 eliminates most of the message strings from the kernel image
1541 and makes the kernel more or less silent. As this makes it
1542 very difficult to diagnose system problems, saying N here is
1543 strongly discouraged.
1544
Matt Mackallc8538a72005-05-01 08:59:01 -07001545config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001546 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001547 default y
1548 help
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001549 Disabling this option eliminates support for BUG and WARN, reducing
1550 the size of your kernel image and potentially quietly ignoring
1551 numerous fatal conditions. You should only consider disabling this
1552 option for embedded systems with no facilities for reporting errors.
1553 Just say Y.
Matt Mackallc8538a72005-05-01 08:59:01 -07001554
Matt Mackall708e9a72006-01-08 01:05:25 -08001555config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001556 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001557 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001558 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001559 help
1560 Enable support for generating core dumps. Disabling saves about 4k.
1561
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001562
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001563config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001564 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001565 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001566 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001567 default y
1568 help
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001569 This option allows to disable the internal PC-Speaker
1570 support, saving some memory.
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001571
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572config BASE_FULL
1573 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001574 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575 help
1576 Disabling this option reduces the size of miscellaneous core
1577 kernel data structures. This saves memory on small machines,
1578 but may reduce performance.
1579
1580config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001581 bool "Enable futex support" if EXPERT
Arnd Bergmann3f2beda2021-10-26 12:03:47 +02001582 depends on !(SPARC32 && SMP)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 default y
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001584 imply RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585 help
1586 Disabling this option will cause the kernel to be built without
1587 support for "fast userspace mutexes". The resulting kernel may not
1588 run glibc-based applications correctly.
1589
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001590config FUTEX_PI
1591 bool
1592 depends on FUTEX && RT_MUTEXES
1593 default y
1594
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001596 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 default y
1598 help
1599 Disabling this option will cause the kernel to be built without
1600 support for epoll family of system calls.
1601
Davide Libenzifba2afa2007-05-10 22:23:13 -07001602config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001603 bool "Enable signalfd() system call" if EXPERT
Davide Libenzifba2afa2007-05-10 22:23:13 -07001604 default y
1605 help
1606 Enable the signalfd() system call that allows to receive signals
1607 on a file descriptor.
1608
1609 If unsure, say Y.
1610
Davide Libenzib215e282007-05-10 22:23:16 -07001611config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001612 bool "Enable timerfd() system call" if EXPERT
Davide Libenzib215e282007-05-10 22:23:16 -07001613 default y
1614 help
1615 Enable the timerfd() system call that allows to receive timer
1616 events on a file descriptor.
1617
1618 If unsure, say Y.
1619
Davide Libenzie1ad7462007-05-10 22:23:19 -07001620config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001621 bool "Enable eventfd() system call" if EXPERT
Davide Libenzie1ad7462007-05-10 22:23:19 -07001622 default y
1623 help
1624 Enable the eventfd() system call that allows to receive both
1625 kernel notification (ie. KAIO) or userspace notifications.
1626
1627 If unsure, say Y.
1628
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001630 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 default y
1632 depends on MMU
1633 help
1634 The shmem is an internal filesystem used to manage shared memory.
1635 It is backed by swap and manages resource limits. It is also exported
1636 to userspace as tmpfs if TMPFS is enabled. Disabling this
1637 option replaces shmem and tmpfs with the much simpler ramfs code,
1638 which may be appropriate on small systems without swap.
1639
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001640config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001641 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001642 default y
1643 help
1644 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001645 by some high performance threaded applications. Disabling
1646 this option saves about 7k.
1647
Jens Axboe2b188cc2019-01-07 10:46:33 -07001648config IO_URING
1649 bool "Enable IO uring support" if EXPERT
Jens Axboe561fb042019-10-24 07:25:42 -06001650 select IO_WQ
Jens Axboe2b188cc2019-01-07 10:46:33 -07001651 default y
1652 help
1653 This option enables support for the io_uring interface, enabling
1654 applications to submit and complete IO through submission and
1655 completion rings that are shared between the kernel and application.
1656
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001657config ADVISE_SYSCALLS
1658 bool "Enable madvise/fadvise syscalls" if EXPERT
1659 default y
1660 help
1661 This option enables the madvise and fadvise syscalls, used by
1662 applications to advise the kernel about their future memory or file
1663 usage, improving performance. If building an embedded system where no
1664 applications use these syscalls, you can disable this option to save
1665 space.
1666
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001667config MEMBARRIER
1668 bool "Enable membarrier() system call" if EXPERT
1669 default y
1670 help
1671 Enable the membarrier() system call that allows issuing memory
1672 barriers across all running threads, which can be used to distribute
1673 the cost of user-space memory barriers asymmetrically by transforming
1674 pairs of memory barriers into pairs consisting of membarrier() and a
1675 compiler barrier.
1676
1677 If unsure, say Y.
1678
Randy Dunlapa751ea32023-12-07 20:58:19 -08001679config KCMP
1680 bool "Enable kcmp() system call" if EXPERT
1681 help
1682 Enable the kernel resource comparison system call. It provides
1683 user-space with the ability to compare two processes to see if they
1684 share a common resource, such as a file descriptor or even virtual
1685 memory space.
1686
1687 If unsure, say N.
1688
1689config RSEQ
1690 bool "Enable rseq() system call" if EXPERT
1691 default y
1692 depends on HAVE_RSEQ
1693 select MEMBARRIER
1694 help
1695 Enable the restartable sequences system call. It provides a
1696 user-space cache for the current CPU number value, which
1697 speeds up getting the current CPU number from user-space,
1698 as well as an ABI to speed up user-space operations on
1699 per-CPU data.
1700
1701 If unsure, say Y.
1702
1703config DEBUG_RSEQ
1704 default n
1705 bool "Enable debugging of rseq() system call" if EXPERT
1706 depends on RSEQ && DEBUG_KERNEL
1707 help
1708 Enable extra debugging checks for the rseq system call.
1709
1710 If unsure, say N.
1711
1712config CACHESTAT_SYSCALL
1713 bool "Enable cachestat() system call" if EXPERT
1714 default y
1715 help
1716 Enable the cachestat system call, which queries the page cache
1717 statistics of a file (number of cached pages, dirty pages,
1718 pages marked for writeback, (recently) evicted pages).
1719
1720 If unsure say Y here.
1721
1722config PC104
1723 bool "PC/104 support" if EXPERT
1724 help
1725 Expose PC/104 form factor device drivers and options available for
1726 selection and configuration. Enable this option if your target
1727 machine has a PC/104 bus.
1728
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001729config KALLSYMS
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001730 bool "Load all symbols for debugging/ksymoops" if EXPERT
1731 default y
1732 help
1733 Say Y here to let the kernel print out symbolic crash information and
1734 symbolic stack backtraces. This increases the size of the kernel
1735 somewhat, as all symbols have to be loaded into the kernel image.
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001736
Zhen Lei30f3bb02022-11-15 16:33:48 +08001737config KALLSYMS_SELFTEST
1738 bool "Test the basic functions and performance of kallsyms"
1739 depends on KALLSYMS
1740 default n
1741 help
1742 Test the basic functions and performance of some interfaces, such as
1743 kallsyms_lookup_name. It also calculates the compression rate of the
1744 kallsyms compression algorithm for the current symbol set.
1745
1746 Start self-test automatically after system startup. Suggest executing
1747 "dmesg | grep kallsyms_selftest" to collect test results. "finish" is
1748 displayed in the last line, indicating that the test is complete.
1749
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001750config KALLSYMS_ALL
1751 bool "Include all symbols in kallsyms"
1752 depends on DEBUG_KERNEL && KALLSYMS
1753 help
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001754 Normally kallsyms only contains the symbols of functions for nicer
1755 OOPS messages and backtraces (i.e., symbols from the text and inittext
Baruch Siachbdf0fe32022-07-07 07:43:29 +03001756 sections). This is sufficient for most cases. And only if you want to
1757 enable kernel live patching, or other less common use cases (e.g.,
1758 when a debugger is used) all symbols are required (i.e., names of
1759 variables from the data sections, etc).
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001760
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001761 This option makes sure that all symbols are loaded into the kernel
1762 image (i.e., symbols from all sections) in cost of increased kernel
1763 size (depending on the kernel configuration, it may be 300KiB or
1764 something like this).
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001765
Baruch Siachbdf0fe32022-07-07 07:43:29 +03001766 Say N unless you really need all symbols, or kernel live patching.
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001767
1768config KALLSYMS_ABSOLUTE_PERCPU
1769 bool
1770 depends on KALLSYMS
1771 default X86_64 && SMP
1772
1773config KALLSYMS_BASE_RELATIVE
1774 bool
1775 depends on KALLSYMS
Ard Biesheuvelcf8e8652022-10-20 15:54:33 +02001776 default y
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001777 help
1778 Instead of emitting them as absolute values in the native word size,
1779 emit the symbol references in the kallsyms table as 32-bit entries,
1780 each containing a relative value in the range [base, base + U32_MAX]
1781 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1782 an absolute value in the range [0, S32_MAX] or a relative value in the
1783 range [base, base + S32_MAX], where base is the lowest relative symbol
1784 address encountered in the image.
1785
1786 On 64-bit builds, this reduces the size of the address table by 50%,
1787 but more importantly, it results in entries whose values are build
1788 time constants, and no relocation pass is required at runtime to fix
1789 up the entries based on the runtime load address of the kernel.
1790
1791# end of the "standard kernel features (expert users)" menu
1792
Mathieu Desnoyers3ccfebe2018-01-29 15:20:11 -05001793config ARCH_HAS_MEMBARRIER_CALLBACKS
1794 bool
1795
Mathieu Desnoyers70216e12018-01-29 15:20:17 -05001796config ARCH_HAS_MEMBARRIER_SYNC_CORE
1797 bool
1798
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001799config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001800 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001801 help
1802 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001803
Sean Christopherson2aef6f32021-11-11 02:07:29 +00001804config GUEST_PERF_EVENTS
1805 bool
1806 depends on HAVE_PERF_EVENTS
1807
Peter Zijlstra906010b2009-09-21 16:08:49 +02001808config PERF_USE_VMALLOC
1809 bool
1810 help
1811 See tools/perf/design.txt for details
1812
Ingo Molnar57c0c152009-09-21 12:20:38 +02001813menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001814
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001815config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001816 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001817 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001818 depends on HAVE_PERF_EVENTS
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001819 select IRQ_WORK
Thomas Gleixner0793a612008-12-04 20:12:29 +01001820 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001821 Enable kernel support for various performance events provided
1822 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001823
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001824 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001825 use of generic tracepoints.
1826
1827 Most modern CPUs support performance events via performance
1828 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001829 types of hw events: such as instructions executed, cachemisses
1830 suffered, or branches mis-predicted - without slowing down the
1831 kernel or applications. These registers can also trigger interrupts
1832 when a threshold number of events have passed - and can thus be
1833 used to profile the code that runs on that CPU.
1834
Ingo Molnar57c0c152009-09-21 12:20:38 +02001835 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001836 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001837 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001838 provides per task and per CPU counters, and it provides event
1839 capabilities on top of those.
1840
1841 Say Y if unsure.
1842
Peter Zijlstra906010b2009-09-21 16:08:49 +02001843config DEBUG_PERF_USE_VMALLOC
1844 default n
1845 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb3071132015-05-04 16:26:39 +10001846 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001847 select PERF_USE_VMALLOC
1848 help
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001849 Use vmalloc memory to back perf mmap() buffers.
Peter Zijlstra906010b2009-09-21 16:08:49 +02001850
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001851 Mostly useful for debugging the vmalloc code on platforms
1852 that don't require it.
Peter Zijlstra906010b2009-09-21 16:08:49 +02001853
Krzysztof Kozlowskie8cf4e92019-12-04 16:52:28 -08001854 Say N if unsure.
Peter Zijlstra906010b2009-09-21 16:08:49 +02001855
Thomas Gleixner0793a612008-12-04 20:12:29 +01001856endmenu
1857
David Howells091f6e22015-07-20 21:16:28 +01001858config SYSTEM_DATA_VERIFICATION
1859 def_bool n
1860 select SYSTEM_TRUSTED_KEYRING
1861 select KEYS
1862 select CRYPTO
David Howellsd43de6c2016-03-03 21:49:27 +00001863 select CRYPTO_RSA
David Howells091f6e22015-07-20 21:16:28 +01001864 select ASYMMETRIC_KEY_TYPE
1865 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
David Howells091f6e22015-07-20 21:16:28 +01001866 select ASN1
1867 select OID_REGISTRY
1868 select X509_CERTIFICATE_PARSER
1869 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001870 help
David Howells091f6e22015-07-20 21:16:28 +01001871 Provide PKCS#7 message verification using the contents of the system
1872 trusted keyring to provide public keys. This then can be used for
1873 module verification, kexec image verification and firmware blob
1874 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001875
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001876config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001877 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001878 help
1879 Say Y here to enable the extended profiling support mechanisms used
Viresh Kumarf8408262021-01-14 17:05:30 +05301880 by profilers.
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001881
Miguel Ojeda2f7ab122021-07-03 16:42:57 +02001882config RUST
1883 bool "Rust support"
1884 depends on HAVE_RUST
1885 depends on RUST_IS_AVAILABLE
1886 depends on !MODVERSIONS
1887 depends on !GCC_PLUGINS
1888 depends on !RANDSTRUCT
Martin Rodriguez Reboredoc1177972023-01-11 12:20:50 -03001889 depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
Miguel Ojeda2f7ab122021-07-03 16:42:57 +02001890 select CONSTRUCTORS
1891 help
1892 Enables Rust support in the kernel.
1893
1894 This allows other Rust-related options, like drivers written in Rust,
1895 to be selected.
1896
1897 It is also required to be able to load external kernel modules
1898 written in Rust.
1899
1900 See Documentation/rust/ for more information.
1901
1902 If unsure, say N.
1903
1904config RUSTC_VERSION_TEXT
1905 string
1906 depends on RUST
1907 default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
1908
1909config BINDGEN_VERSION_TEXT
1910 string
1911 depends on RUST
1912 default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
1913
Ingo Molnar5f87f112008-07-23 14:15:22 +02001914#
1915# Place an empty function call at each tracepoint site. Can be
1916# dynamically changed for a probe function.
1917#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001918config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001919 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001920
Eric DeVolder89cde452023-07-12 12:15:32 -04001921source "kernel/Kconfig.kexec"
1922
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923endmenu # General setup
1924
Christoph Hellwig15724972018-07-31 13:39:30 +02001925source "arch/Kconfig"
1926
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001927config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001928 bool
Sebastian Andrzej Siewior1c6f9ec2022-02-08 18:21:10 +01001929 default y if PREEMPT_RT
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001930
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931config BASE_SMALL
1932 int
1933 default 0 if BASE_FULL
1934 default 1 if !BASE_FULL
1935
Thiago Jung Bauermannc8424e72019-07-04 15:57:34 -03001936config MODULE_SIG_FORMAT
1937 def_bool n
1938 select SYSTEM_DATA_VERIFICATION
1939
Christophe Leroy73b4fc92022-07-12 07:52:33 +02001940source "kernel/module/Kconfig"
Peter Zijlstra6c9692e22015-05-27 11:09:37 +09301941
Rusty Russell98a79d62008-12-13 21:19:41 +10301942config INIT_ALL_POSSIBLE
1943 bool
1944 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301945 Back when each arch used to define their own cpu_online_mask and
1946 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301947 with all 1s, and others with all 0s. When they were centralised,
1948 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001949 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301950
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001951source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001952
1953config PREEMPT_NOTIFIERS
1954 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001955
Steffen Klassert16295be2010-01-06 19:47:10 +11001956config PADATA
1957 depends on SMP
1958 bool
1959
David Howells4520c6a2012-09-21 23:31:13 +01001960config ASN1
1961 tristate
1962 help
1963 Build a simple ASN.1 grammar compiler that produces a bytecode output
1964 that can be interpreted by the ASN.1 stream decoder and used to
1965 inform it as to what tags are to be expected in a stream and what
1966 functions to call on what tags.
1967
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001968source "kernel/Kconfig.locks"
Mathieu Desnoyerse61938a2018-01-29 15:20:15 -05001969
Daniel Borkmann0ebeea82020-05-15 12:11:16 +02001970config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1971 bool
1972
Mathieu Desnoyerse61938a2018-01-29 15:20:15 -05001973config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
1974 bool
Dominik Brodowski1bd21c62018-04-05 11:53:01 +02001975
1976# It may be useful for an architecture to override the definitions of the
Dominik Brodowski7303e302018-04-05 11:53:03 +02001977# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
1978# and the COMPAT_ variants in <linux/compat.h>, in particular to use a
1979# different calling convention for syscalls. They can also override the
1980# macros for not-implemented syscalls in kernel/sys_ni.c and
1981# kernel/time/posix-stubs.c. All these overrides need to be available in
1982# <asm/syscall_wrapper.h>.
Dominik Brodowski1bd21c62018-04-05 11:53:01 +02001983config ARCH_HAS_SYSCALL_WRAPPER
1984 def_bool n