blob: 1217fc62ca6193f1d12fdfb90525c7a33c31732d [file] [log] [blame]
Roman Zippelface4372006-06-08 22:12:45 -07001config DEFCONFIG_LIST
2 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -07003 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -07004 option defconfig_list
Masahiro Yamada104daea2018-05-28 18:21:40 +09005 default "/lib/modules/$(UNAME_RELEASE)/.config"
Roman Zippelface4372006-06-08 22:12:45 -07006 default "/etc/kernel-config"
Masahiro Yamada104daea2018-05-28 18:21:40 +09007 default "/boot/config-$(UNAME_RELEASE)"
8 default ARCH_DEFCONFIG
9 default "arch/$(ARCH)/defconfig"
Roman Zippelface4372006-06-08 22:12:45 -070010
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070011config CONSTRUCTORS
12 bool
13 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070014
Peter Zijlstrae360adb2010-10-14 14:01:34 +080015config IRQ_WORK
16 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +080017
David Daney1dbdc6f2012-04-19 14:59:57 -070018config BUILDTIME_EXTABLE_SORT
19 bool
20
Andy Lutomirskic65eacb2016-09-13 14:29:24 -070021config THREAD_INFO_IN_TASK
22 bool
23 help
24 Select this to move thread_info off the stack into task_struct. To
25 make this work, an arch will need to remove all thread_info fields
26 except flags and fix any runtime bugs.
27
Andy Lutomirskic6c314a2016-09-15 22:45:43 -070028 One subtle change that will be needed is to use try_get_task_stack()
29 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
30
Al Boldiff0cfc62007-07-31 00:39:23 -070031menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Linus Torvalds1da177e2005-04-16 15:20:36 -070033config BROKEN
34 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36config BROKEN_ON_SMP
37 bool
38 depends on BROKEN || !SMP
39 default y
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041config INIT_ENV_ARG_LIMIT
42 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070043 default 32 if !UML
44 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080046 Maximum of each of the number of arguments and environment
47 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Jiri Slaby4bb16672013-05-22 10:56:24 +020049config COMPILE_TEST
50 bool "Compile also drivers which will not load"
Richard Weinbergerbc083a62016-08-02 14:03:27 -070051 depends on !UML
Jiri Slaby4bb16672013-05-22 10:56:24 +020052 default n
53 help
54 Some drivers can be compiled on a different platform than they are
55 intended to be run on. Despite they cannot be loaded there (or even
56 when they load they cannot be used due to missing HW support),
57 developers still, opposing to distributors, might want to build such
58 drivers to compile-test them.
59
60 If you are a developer and want to build everything available, say Y
61 here. If you are a user/distributor, say N here to exclude useless
62 drivers to be distributed.
63
Linus Torvalds1da177e2005-04-16 15:20:36 -070064config LOCALVERSION
65 string "Local version - append to kernel release"
66 help
67 Append an extra string to the end of your kernel version.
68 This will show up when you type uname, for example.
69 The string you set here will be appended after the contents of
70 any files with a filename matching localversion* in your
71 object and source tree, in that order. Your total string can
72 be a maximum of 64 characters.
73
Ryan Andersonaaebf432005-07-31 04:57:49 -040074config LOCALVERSION_AUTO
75 bool "Automatically append version information to the version string"
76 default y
Alexey Dobriyanac3339b2016-08-02 14:07:21 -070077 depends on !COMPILE_TEST
Ryan Andersonaaebf432005-07-31 04:57:49 -040078 help
79 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020080 release tree by looking for git tags that belong to the current
81 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040082
83 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020084 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040085 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020086 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -040087
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020088 (The actual string used here is the first eight characters produced
89 by running the command:
90
91 $ git rev-parse --verify HEAD
92
93 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -040094
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -080095config HAVE_KERNEL_GZIP
96 bool
97
98config HAVE_KERNEL_BZIP2
99 bool
100
101config HAVE_KERNEL_LZMA
102 bool
103
Lasse Collin3ebe1242011-01-12 17:01:23 -0800104config HAVE_KERNEL_XZ
105 bool
106
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800107config HAVE_KERNEL_LZO
108 bool
109
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700110config HAVE_KERNEL_LZ4
111 bool
112
Alain Knaff30d65db2009-01-04 22:46:17 +0100113choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800114 prompt "Kernel compression mode"
115 default KERNEL_GZIP
H. Peter Anvin2d3c6272013-11-14 21:43:47 -0800116 depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800117 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100118 The linux kernel is a kind of self-extracting executable.
119 Several compression algorithms are available, which differ
120 in efficiency, compression and decompression speed.
121 Compression speed is only relevant when building a kernel.
122 Decompression speed is relevant at each boot.
123
124 If you have any problems with bzip2 or lzma compressed
125 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
126 version of this functionality (bzip2 only), for 2.4, was
127 supplied by Christian Ludwig)
128
129 High compression options are mostly useful for users, who
130 are low on disk space (embedded systems), but for whom ram
131 size matters less.
132
133 If in doubt, select 'gzip'
134
135config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800136 bool "Gzip"
137 depends on HAVE_KERNEL_GZIP
138 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800139 The old and tried gzip compression. It provides a good balance
140 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100141
142config KERNEL_BZIP2
143 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800144 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100145 help
146 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700147 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800148 size is about 10% smaller with bzip2, in comparison to gzip.
149 Bzip2 uses a large amount of memory. For modern kernels you
150 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100151
152config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800153 bool "LZMA"
154 depends on HAVE_KERNEL_LZMA
155 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700156 This compression algorithm's ratio is best. Decompression speed
157 is between gzip and bzip2. Compression is slowest.
158 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100159
Lasse Collin3ebe1242011-01-12 17:01:23 -0800160config KERNEL_XZ
161 bool "XZ"
162 depends on HAVE_KERNEL_XZ
163 help
164 XZ uses the LZMA2 algorithm and instruction set specific
165 BCJ filters which can improve compression ratio of executable
166 code. The size of the kernel is about 30% smaller with XZ in
167 comparison to gzip. On architectures for which there is a BCJ
168 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
169 will create a few percent smaller kernel than plain LZMA.
170
171 The speed is about the same as with LZMA: The decompression
172 speed of XZ is better than that of bzip2 but worse than gzip
173 and LZO. Compression is slow.
174
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800175config KERNEL_LZO
176 bool "LZO"
177 depends on HAVE_KERNEL_LZO
178 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700179 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200180 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800181 (both compression and decompression) is the fastest.
182
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700183config KERNEL_LZ4
184 bool "LZ4"
185 depends on HAVE_KERNEL_LZ4
186 help
187 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
188 A preliminary version of LZ4 de/compression tool is available at
189 <https://code.google.com/p/lz4/>.
190
191 Its compression ratio is worse than LZO. The size of the kernel
192 is about 8% bigger than LZO. But the decompression speed is
193 faster than LZO.
194
Alain Knaff30d65db2009-01-04 22:46:17 +0100195endchoice
196
Josh Triplettbd5dc172011-06-15 15:08:28 -0700197config DEFAULT_HOSTNAME
198 string "Default hostname"
199 default "(none)"
200 help
201 This option determines the default system hostname before userspace
202 calls sethostname(2). The kernel traditionally uses "(none)" here,
203 but you may wish to use a different default here to make a minimal
204 system more usable with less configuration.
205
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206config SWAP
207 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200208 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 default y
210 help
211 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100212 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 used to provide more virtual memory than the actual RAM present
214 in your computer. If unsure say Y.
215
216config SYSVIPC
217 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 ---help---
219 Inter Process Communication is a suite of library functions and
220 system calls which let processes (running programs) synchronize and
221 exchange information. It is generally considered to be a good thing,
222 and some programs won't run unless you say Y here. In particular, if
223 you want to run the DOS emulator dosemu under Linux (read the
224 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
225 you'll need to say Y here.
226
227 You can find documentation about IPC with "info ipc" and also in
228 section 6.4 of the Linux Programmer's Guide, available from
229 <http://www.tldp.org/guides.html>.
230
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800231config SYSVIPC_SYSCTL
232 bool
233 depends on SYSVIPC
234 depends on SYSCTL
235 default y
236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237config POSIX_MQUEUE
238 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700239 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 ---help---
241 POSIX variant of message queues is a part of IPC. In POSIX message
242 queues every message has a priority which decides about succession
243 of receiving it by a process. If you want to compile and run
244 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200245 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
247 POSIX message queues are visible as a filesystem called 'mqueue'
248 and can be mounted somewhere if you want to do filesystem
249 operations on message queues.
250
251 If unsure, say Y.
252
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700253config POSIX_MQUEUE_SYSCTL
254 bool
255 depends on POSIX_MQUEUE
256 depends on SYSCTL
257 default y
258
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700259config CROSS_MEMORY_ATTACH
260 bool "Enable process_vm_readv/writev syscalls"
261 depends on MMU
262 default y
263 help
264 Enabling this option adds the system calls process_vm_readv and
265 process_vm_writev which allow a process with the correct privileges
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700266 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700267 See the man page for more details.
268
Josh Triplett69369a72014-04-03 14:48:27 -0700269config USELIB
270 bool "uselib syscall"
Riku Voipiob2113a42016-01-15 16:58:13 -0800271 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
Josh Triplett69369a72014-04-03 14:48:27 -0700272 help
273 This option enables the uselib syscall, a system call used in the
274 dynamic linker from libc5 and earlier. glibc does not use this
275 system call. If you intend to run programs built on libc5 or
276 earlier, you may need to enable this syscall. Current systems
277 running glibc can safely disable this.
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279config AUDIT
280 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100281 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 help
283 Enable auditing infrastructure that can be used with another
284 kernel subsystem, such as SELinux (which requires this for
Paul Moorecb74ed22016-01-13 09:18:55 -0500285 logging of avc messages output). System call auditing is included
286 on architectures which support it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900288config HAVE_ARCH_AUDITSYSCALL
289 bool
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291config AUDITSYSCALL
Paul Moorecb74ed22016-01-13 09:18:55 -0500292 def_bool y
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900293 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
Eric Paris939a67f2009-12-17 20:12:06 -0500295config AUDIT_WATCH
296 def_bool y
297 depends on AUDITSYSCALL
298 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
Al Viro74c3cbe2007-07-22 08:04:18 -0400300config AUDIT_TREE
301 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400302 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500303 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400304
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000305source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200306source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000307
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200308menu "CPU/Task time and stats accounting"
309
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200310config VIRT_CPU_ACCOUNTING
311 bool
312
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200313choice
314 prompt "Cputime accounting"
315 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100316 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200317
318# Kind of a stub config for the pure tick based cputime accounting
319config TICK_CPU_ACCOUNTING
320 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200321 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200322 help
323 This is the basic tick based cputime accounting that maintains
324 statistics about user, system and idle time spent on per jiffies
325 granularity.
326
327 If unsure, say Y.
328
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200329config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200330 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200331 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200332 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200333 help
334 Select this option to enable more accurate task and CPU time
335 accounting. This is done by reading a CPU counter on each
336 kernel entry and exit and on transitions within the kernel
337 between system, softirq and hardirq state, so there is a
338 small performance impact. In the case of s390 or IBM POWER > 5,
339 this also enables accounting of stolen time on logically-partitioned
340 systems.
341
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200342config VIRT_CPU_ACCOUNTING_GEN
343 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700344 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700345 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200346 select VIRT_CPU_ACCOUNTING
347 select CONTEXT_TRACKING
348 help
349 Select this option to enable task and CPU time accounting on full
350 dynticks systems. This accounting is implemented by watching every
351 kernel-user boundaries using the context tracking subsystem.
352 The accounting is thus performed at the expense of some significant
353 overhead.
354
355 For now this is only useful if you are working on the full
356 dynticks subsystem development.
357
358 If unsure, say N.
359
Rik van Rielb58c3582016-07-13 16:50:02 +0200360endchoice
361
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200362config IRQ_TIME_ACCOUNTING
363 bool "Fine granularity task level IRQ time accounting"
Rik van Rielb58c3582016-07-13 16:50:02 +0200364 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200365 help
366 Select this option to enable fine granularity task irq time
367 accounting. This is done by reading a timestamp on each
368 transitions between softirq and hardirq state, so there can be a
369 small performance impact.
370
371 If in doubt, say N here.
372
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200373config BSD_PROCESS_ACCT
374 bool "BSD Process Accounting"
Iulia Manda28138932015-04-15 16:16:41 -0700375 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200376 help
377 If you say Y here, a user level program will be able to instruct the
378 kernel (via a special system call) to write process accounting
379 information to a file: whenever a process exits, information about
380 that process will be appended to the file by the kernel. The
381 information includes things such as creation time, owning user,
382 command name, memory usage, controlling terminal etc. (the complete
383 list is in the struct acct in <file:include/linux/acct.h>). It is
384 up to the user level program to do useful things with this
385 information. This is generally a good idea, so say Y.
386
387config BSD_PROCESS_ACCT_V3
388 bool "BSD Process Accounting version 3 file format"
389 depends on BSD_PROCESS_ACCT
390 default n
391 help
392 If you say Y here, the process accounting information is written
393 in a new file format that also logs the process IDs of each
394 process and it's parent. Note that this file format is incompatible
395 with previous v0/v1/v2 file formats, so you will need updated tools
396 for processing it. A preliminary version of these tools is available
397 at <http://www.gnu.org/software/acct/>.
398
399config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700400 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200401 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700402 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200403 default n
404 help
405 Export selected statistics for tasks/processes through the
406 generic netlink interface. Unlike BSD process accounting, the
407 statistics are available during the lifetime of tasks/processes as
408 responses to commands. Like BSD accounting, they are sent to user
409 space on task exit.
410
411 Say N if unsure.
412
413config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700414 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200415 depends on TASKSTATS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530416 select SCHED_INFO
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200417 help
418 Collect information on time spent by a task waiting for system
419 resources like cpu, synchronous block I/O completion and swapping
420 in pages. Such statistics can help in setting a task's priorities
421 relative to other tasks for cpu, io, rss limits etc.
422
423 Say N if unsure.
424
425config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700426 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200427 depends on TASKSTATS
428 help
429 Collect extended task accounting data and send the data
430 to userland for processing over the taskstats interface.
431
432 Say N if unsure.
433
434config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700435 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200436 depends on TASK_XACCT
437 help
438 Collect information on the number of bytes of storage I/O which this
439 task has caused.
440
441 Say N if unsure.
442
443endmenu # "CPU/Task time and stats accounting"
444
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200445config CPU_ISOLATION
446 bool "CPU isolation"
Geert Uytterhoeven414a2dc2018-01-02 12:13:10 +0100447 depends on SMP || COMPILE_TEST
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100448 default y
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200449 help
450 Make sure that CPUs running critical tasks are not disturbed by
451 any source of "noise" such as unbound workqueues, timers, kthreads...
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100452 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
453 the "isolcpus=" boot parameter.
454
455 Say Y if unsure.
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200456
Paul E. McKenney0af92d42017-05-17 08:43:40 -0700457source "kernel/rcu/Kconfig"
Mike Travisc903ff82009-01-15 12:28:29 -0800458
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700459config BUILD_BIN2C
460 bool
461 default n
462
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700464 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700465 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 ---help---
467 This option enables the complete Linux kernel ".config" file
468 contents to be saved in the kernel. It provides documentation
469 of which kernel options are used in a running kernel or in an
470 on-disk kernel. This information can be extracted from the kernel
471 image file with the script scripts/extract-ikconfig and used as
472 input to rebuild the current kernel or to build another kernel.
473 It can also be extracted from a running kernel by reading
474 /proc/config.gz if enabled (below).
475
476config IKCONFIG_PROC
477 bool "Enable access to .config through /proc/config.gz"
478 depends on IKCONFIG && PROC_FS
479 ---help---
480 This option enables access to the kernel configuration file
481 through /proc/config.gz.
482
Alistair John Strachan794543a2007-05-08 00:31:15 -0700483config LOG_BUF_SHIFT
484 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Ingo Molnarfb39f982015-07-01 10:19:11 +0200485 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700486 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700487 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700488 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700489 Select the minimal kernel log buffer size as a power of 2.
490 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
491 parameter, see below. Any higher size also might be forced
492 by "log_buf_len" boot parameter.
493
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700494 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700495 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700496 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700497 15 => 32 KB
498 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700499 13 => 8 KB
500 12 => 4 KB
501
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700502config LOG_CPU_MAX_BUF_SHIFT
503 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700504 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700505 range 0 21
506 default 12 if !BASE_SMALL
507 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700508 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700509 help
510 This option allows to increase the default ring buffer size
511 according to the number of CPUs. The value defines the contribution
512 of each CPU as a power of 2. The used space is typically only few
513 lines however it might be much more when problems are reported,
514 e.g. backtraces.
515
516 The increased size means that a new buffer has to be allocated and
517 the original static one is unused. It makes sense only on systems
518 with more CPUs. Therefore this value is used only when the sum of
519 contributions is greater than the half of the default kernel ring
520 buffer as defined by LOG_BUF_SHIFT. The default values are set
521 so that more than 64 CPUs are needed to trigger the allocation.
522
523 Also this option is ignored when "log_buf_len" kernel parameter is
524 used as it forces an exact (power of two) size of the ring buffer.
525
526 The number of possible CPUs is used for this computation ignoring
Geert Uytterhoeven5e0d8d52016-06-05 10:47:02 +0200527 hotplugging making the computation optimal for the worst case
528 scenario while allowing a simple algorithm to be used from bootup.
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700529
530 Examples shift values and their meaning:
531 17 => 128 KB for each CPU
532 16 => 64 KB for each CPU
533 15 => 32 KB for each CPU
534 14 => 16 KB for each CPU
535 13 => 8 KB for each CPU
536 12 => 4 KB for each CPU
537
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900538config PRINTK_SAFE_LOG_BUF_SHIFT
539 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
Petr Mladek427934b2016-05-20 17:00:39 -0700540 range 10 21
541 default 13
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900542 depends on PRINTK
Petr Mladek427934b2016-05-20 17:00:39 -0700543 help
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900544 Select the size of an alternate printk per-CPU buffer where messages
545 printed from usafe contexts are temporary stored. One example would
546 be NMI messages, another one - printk recursion. The messages are
547 copied to the main log buffer in a safe context to avoid a deadlock.
548 The value defines the size as a power of 2.
Petr Mladek427934b2016-05-20 17:00:39 -0700549
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900550 Those messages are rare and limited. The largest one is when
Petr Mladek427934b2016-05-20 17:00:39 -0700551 a backtrace is printed. It usually fits into 4KB. Select
552 8KB if you want to be on the safe side.
553
554 Examples:
555 17 => 128 KB for each CPU
556 16 => 64 KB for each CPU
557 15 => 32 KB for each CPU
558 14 => 16 KB for each CPU
559 13 => 8 KB for each CPU
560 12 => 4 KB for each CPU
561
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800562#
563# Architectures with an unreliable sched_clock() should select this:
564#
565config HAVE_UNSTABLE_SCHED_CLOCK
566 bool
567
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700568config GENERIC_SCHED_CLOCK
569 bool
570
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200571#
572# For architectures that want to enable the support for NUMA-affine scheduler
573# balancing logic:
574#
575config ARCH_SUPPORTS_NUMA_BALANCING
576 bool
577
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100578#
Mel Gorman72b252a2015-09-04 15:47:32 -0700579# For architectures that prefer to flush all TLBs after a number of pages
580# are unmapped instead of sending one IPI per page to flush. The architecture
581# must provide guarantees on what happens if a clean TLB cache entry is
582# written after the unmap. Details are in mm/rmap.c near the check for
583# should_defer_flush. The architecture should also consider if the full flush
584# and the refill costs are offset by the savings of sending fewer IPIs.
585config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
586 bool
587
588#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100589# For architectures that know their GCC __int128 support is sound
590#
591config ARCH_SUPPORTS_INT128
592 bool
593
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200594# For architectures that (ab)use NUMA to represent different memory regions
595# all cpu-local but of different latencies, such as SuperH.
596#
597config ARCH_WANT_NUMA_VARIABLE_LOCALITY
598 bool
599
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200600config NUMA_BALANCING
601 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200602 depends on ARCH_SUPPORTS_NUMA_BALANCING
603 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
604 depends on SMP && NUMA && MIGRATION
605 help
606 This option adds support for automatic NUMA aware memory/task placement.
607 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400608 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200609
610 This system will be inactive on UMA systems.
611
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800612config NUMA_BALANCING_DEFAULT_ENABLED
613 bool "Automatically enable NUMA aware memory/task placement"
614 default y
615 depends on NUMA_BALANCING
616 help
617 If set, automatic NUMA balancing will be enabled if running on a NUMA
618 machine.
619
Li Zefan23964d22009-01-15 13:50:58 -0800620menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500621 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500622 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700623 help
Li Zefan23964d22009-01-15 13:50:58 -0800624 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800625 use with process control subsystems such as Cpusets, CFS, memory
626 controls or device isolation.
627 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800628 - Documentation/scheduler/sched-design-CFS.txt (CFS)
seokhoon.yoon9991a9c2016-08-02 14:03:13 -0700629 - Documentation/cgroup-v1/ (features for grouping, isolation
Li Zefan45ce80f2009-01-15 13:50:59 -0800630 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700631
632 Say N if unsure.
633
Li Zefan23964d22009-01-15 13:50:58 -0800634if CGROUPS
635
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800636config PAGE_COUNTER
637 bool
638
Andrew Mortonc255a452012-07-31 16:43:02 -0700639config MEMCG
Johannes Weinera0166ec2015-12-17 17:19:56 -0500640 bool "Memory controller"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800641 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500642 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800643 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500644 Provides control over the memory footprint of tasks in a cgroup.
Balbir Singh00f0b822008-03-04 14:28:39 -0800645
Andrew Mortonc255a452012-07-31 16:43:02 -0700646config MEMCG_SWAP
Johannes Weinera0166ec2015-12-17 17:19:56 -0500647 bool "Swap controller"
Andrew Mortonc255a452012-07-31 16:43:02 -0700648 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800649 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500650 Provides control over the swap space consumed by tasks in a cgroup.
651
Andrew Mortonc255a452012-07-31 16:43:02 -0700652config MEMCG_SWAP_ENABLED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500653 bool "Swap controller enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700654 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800655 default y
656 help
657 Memory Resource Controller Swap Extension comes with its price in
658 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700659 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -0700660 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -0800661 parameter should have this option unselected.
662 For those who want to have the feature enabled by default should
663 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700664 then swapaccount=0 does the trick).
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800665
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500666config BLK_CGROUP
667 bool "IO controller"
668 depends on BLOCK
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700669 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500670 ---help---
671 Generic block IO controller cgroup interface. This is the common
672 cgroup interface which should be used by various IO controlling
673 policies.
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700674
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500675 Currently, CFQ IO scheduler uses it to recognize task groups and
676 control disk bandwidth allocation (proportional time slice allocation)
677 to such task groups. It is also used by bio throttling logic in
678 block layer to implement upper limit in IO rates on a device.
Stephane Eraniane5d13672011-02-14 11:20:01 +0200679
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500680 This option only enables generic Block IO controller infrastructure.
681 One needs to also enable actual IO controlling logic/policy. For
682 enabling proportional weight division of disk bandwidth in CFQ, set
683 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
684 CONFIG_BLK_DEV_THROTTLING=y.
685
seokhoon.yoon9991a9c2016-08-02 14:03:13 -0700686 See Documentation/cgroup-v1/blkio-controller.txt for more information.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500687
688config DEBUG_BLK_CGROUP
689 bool "IO controller debugging"
690 depends on BLK_CGROUP
691 default n
692 ---help---
693 Enable some debugging help. Currently it exports additional stat
694 files in a cgroup which can be useful for debugging.
695
696config CGROUP_WRITEBACK
697 bool
698 depends on MEMCG && BLK_CGROUP
699 default y
Stephane Eraniane5d13672011-02-14 11:20:01 +0200700
Dhaval Giani7c941432010-01-20 13:26:18 +0100701menuconfig CGROUP_SCHED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500702 bool "CPU controller"
Dhaval Giani7c941432010-01-20 13:26:18 +0100703 default n
704 help
705 This feature lets CPU scheduler recognize task groups and control CPU
706 bandwidth allocation to such task groups. It uses cgroups to group
707 tasks.
708
709if CGROUP_SCHED
710config FAIR_GROUP_SCHED
711 bool "Group scheduling for SCHED_OTHER"
712 depends on CGROUP_SCHED
713 default CGROUP_SCHED
714
Paul Turnerab84d312011-07-21 09:43:28 -0700715config CFS_BANDWIDTH
716 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -0700717 depends on FAIR_GROUP_SCHED
718 default n
719 help
720 This option allows users to define CPU bandwidth rates (limits) for
721 tasks running within the fair group scheduler. Groups with no limit
722 set are considered to be unconstrained and will run with no
723 restriction.
Sebastian Andrzej Siewiorcd33d882018-05-15 18:53:28 +0200724 See Documentation/scheduler/sched-bwc.txt for more information.
Paul Turnerab84d312011-07-21 09:43:28 -0700725
Dhaval Giani7c941432010-01-20 13:26:18 +0100726config RT_GROUP_SCHED
727 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +0100728 depends on CGROUP_SCHED
729 default n
730 help
731 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800732 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100733 schedule realtime tasks for non-root users until you allocate
734 realtime bandwidth for them.
735 See Documentation/scheduler/sched-rt-group.txt for more information.
736
737endif #CGROUP_SCHED
738
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500739config CGROUP_PIDS
740 bool "PIDs controller"
741 help
742 Provides enforcement of process number limits in the scope of a
743 cgroup. Any attempt to fork more processes than is allowed in the
744 cgroup will fail. PIDs are fundamentally a global resource because it
745 is fairly trivial to reach PID exhaustion before you reach even a
746 conservative kmemcg limit. As a result, it is possible to grind a
747 system to halt without being limited by other cgroup policies. The
Parav Pandit6cc578d2016-03-05 11:30:56 +0530748 PIDs controller is designed to stop this from happening.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500749
750 It should be noted that organisational operations (such as attaching
Parav Pandit6cc578d2016-03-05 11:30:56 +0530751 to a cgroup hierarchy will *not* be blocked by the PIDs controller),
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500752 since the PIDs limit only affects a process's ability to fork, not to
753 attach to a cgroup.
754
Parav Pandit39d3e752017-01-10 00:02:13 +0000755config CGROUP_RDMA
756 bool "RDMA controller"
757 help
758 Provides enforcement of RDMA resources defined by IB stack.
759 It is fairly easy for consumers to exhaust RDMA resources, which
760 can result into resource unavailability to other consumers.
761 RDMA controller is designed to stop this from happening.
762 Attaching processes with active RDMA resources to the cgroup
763 hierarchy is allowed even if can cross the hierarchy's limit.
764
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500765config CGROUP_FREEZER
766 bool "Freezer controller"
767 help
768 Provides a way to freeze and unfreeze all tasks in a
769 cgroup.
770
Johannes Weiner489c2a22016-01-20 15:02:41 -0800771 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
772 controller includes important in-kernel memory consumers per default.
773
774 If you're using cgroup2, say N.
775
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500776config CGROUP_HUGETLB
777 bool "HugeTLB controller"
778 depends on HUGETLB_PAGE
779 select PAGE_COUNTER
Vivek Goyalafc24d42010-04-26 19:27:56 +0200780 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500781 help
782 Provides a cgroup controller for HugeTLB pages.
783 When you enable this, you can put a per cgroup limit on HugeTLB usage.
784 The limit is enforced during page fault. Since HugeTLB doesn't
785 support page reclaim, enforcing the limit at page fault time implies
786 that, the application will get SIGBUS signal if it tries to access
787 HugeTLB pages beyond its limit. This requires the application to know
788 beforehand how much HugeTLB pages it would require for its use. The
789 control group is tracked in the third page lru pointer. This means
790 that we cannot use the controller with huge page less than 3 pages.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200791
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500792config CPUSETS
793 bool "Cpuset controller"
Nicolas Pitree1d4eee2017-06-14 13:19:23 -0400794 depends on SMP
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500795 help
796 This option will let you create and manage CPUSETs which
797 allow dynamically partitioning a system into sets of CPUs and
798 Memory Nodes and assigning tasks to run only within those sets.
799 This is primarily useful on large SMP or NUMA systems.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200800
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500801 Say N if unsure.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200802
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500803config PROC_PID_CPUSET
804 bool "Include legacy /proc/<pid>/cpuset file"
805 depends on CPUSETS
Tejun Heo89e9b9e2015-05-22 17:13:36 -0400806 default y
807
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500808config CGROUP_DEVICE
809 bool "Device controller"
810 help
811 Provides a cgroup controller implementing whitelists for
812 devices which a process in the cgroup can mknod or open.
813
814config CGROUP_CPUACCT
815 bool "Simple CPU accounting controller"
816 help
817 Provides a simple controller for monitoring the
818 total CPU consumed by the tasks in a cgroup.
819
820config CGROUP_PERF
821 bool "Perf controller"
822 depends on PERF_EVENTS
823 help
824 This option extends the perf per-cpu mode to restrict monitoring
825 to threads which belong to the cgroup specified and run on the
826 designated cpu.
827
828 Say N if unsure.
829
Daniel Mack30070982016-11-23 16:52:26 +0100830config CGROUP_BPF
831 bool "Support for eBPF programs attached to cgroups"
Andy Lutomirski483c4932016-12-16 08:33:45 -0800832 depends on BPF_SYSCALL
833 select SOCK_CGROUP_DATA
Daniel Mack30070982016-11-23 16:52:26 +0100834 help
835 Allow attaching eBPF programs to a cgroup using the bpf(2)
836 syscall command BPF_PROG_ATTACH.
837
838 In which context these programs are accessed depends on the type
839 of attachment. For instance, programs that are attached using
840 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
841 inet sockets.
842
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500843config CGROUP_DEBUG
Waiman Long23b0be42017-06-13 17:18:03 -0400844 bool "Debug controller"
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500845 default n
Waiman Long23b0be42017-06-13 17:18:03 -0400846 depends on DEBUG_KERNEL
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500847 help
848 This option enables a simple controller that exports
Waiman Long23b0be42017-06-13 17:18:03 -0400849 debugging information about the cgroups framework. This
850 controller is for control cgroup debugging only. Its
851 interfaces are not stable.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500852
853 Say N.
854
Arnd Bergmann73b35142017-01-10 13:08:06 +0100855config SOCK_CGROUP_DATA
856 bool
857 default n
858
Li Zefan23964d22009-01-15 13:50:58 -0800859endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800860
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700861menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800862 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -0700863 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -0800864 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800865 help
866 Provides the way to make tasks work with different objects using
867 the same id. For example same IPC id may refer to different objects
868 or same user id or pid may refer to different tasks when used in
869 different namespaces.
870
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700871if NAMESPACES
872
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800873config UTS_NS
874 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700875 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800876 help
877 In this namespace tasks see different info provided with the
878 uname() system call
879
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800880config IPC_NS
881 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700882 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700883 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800884 help
885 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700886 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800887
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800888config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -0700889 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -0800890 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800891 help
892 This allows containers, i.e. vservers, to use user namespaces
893 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -0800894
895 When user namespaces are enabled in the kernel it is
Johannes Weinerd886f4e2016-01-20 15:02:47 -0800896 recommended that the MEMCG option also be enabled and that
897 user-space use the memory control groups to limit the amount
898 of memory a memory unprivileged users can use.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -0800899
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800900 If unsure, say N.
901
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800902config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700903 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700904 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800905 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300906 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100907 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800908 pid namespaces. This is a building block of containers.
909
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800910config NET_NS
911 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700912 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700913 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800914 help
915 Allow user space to create what appear to be multiple instances
916 of the network stack.
917
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700918endif # NAMESPACES
919
Mike Galbraith5091faa2010-11-30 14:18:03 +0100920config SCHED_AUTOGROUP
921 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +0100922 select CGROUPS
923 select CGROUP_SCHED
924 select FAIR_GROUP_SCHED
925 help
926 This option optimizes the scheduler for common desktop workloads by
927 automatically creating and populating task groups. This separation
928 of workloads isolates aggressive CPU burners (like build jobs) from
929 desktop applications. Task group autogeneration is currently based
930 upon task session.
931
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700932config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100933 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700934 depends on SYSFS
935 default n
936 help
937 This option adds code that switches the layout of the "block" class
938 devices, to not show up in /sys/class/block/, but only in
939 /sys/block/.
940
941 This switch is only active when the sysfs.deprecated=1 boot option is
942 passed or the SYSFS_DEPRECATED_V2 option is set.
943
944 This option allows new kernels to run on old distributions and tools,
945 which might get confused by /sys/class/block/. Since 2007/2008 all
946 major distributions and tools handle this just fine.
947
948 Recent distributions and userspace tools after 2009/2010 depend on
949 the existence of /sys/class/block/, and will not work with this
950 option enabled.
951
952 Only if you are using a new kernel on an old distribution, you might
953 need to say Y here.
954
955config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100956 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700957 default n
958 depends on SYSFS
959 depends on SYSFS_DEPRECATED
960 help
961 Enable deprecated sysfs by default.
962
963 See the CONFIG_SYSFS_DEPRECATED option for more details about this
964 option.
965
966 Only if you are using a new kernel on an old distribution, you might
967 need to say Y here. Even then, odds are you would not need it
968 enabled, you can always pass the boot option if absolutely necessary.
969
970config RELAY
971 bool "Kernel->user space relay support (formerly relayfs)"
Peter Zijlstra26b56792016-10-11 13:54:33 -0700972 select IRQ_WORK
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700973 help
974 This option enables support for relay interface support in
975 certain file systems (such as debugfs).
976 It is designed to provide an efficient mechanism for tools and
977 facilities to relay large amounts of data from kernel space to
978 user space.
979
980 If unsure, say N.
981
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800982config BLK_DEV_INITRD
983 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800984 help
985 The initial RAM filesystem is a ramfs which is loaded by the
986 boot loader (loadlin or lilo) and that is mounted as root
987 before the normal boot procedure. It is typically used to
988 load modules needed to mount the "real" root file system,
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -0200989 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800990
991 If RAM disk support (BLK_DEV_RAM) is also included, this
992 also enables initial RAM disk (initrd) support and adds
993 15 Kbytes (more on some other architectures) to the kernel size.
994
995 If unsure say Y.
996
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -0800997if BLK_DEV_INITRD
998
Sam Ravnborgdbec4862005-08-10 20:44:50 +0200999source "usr/Kconfig"
1000
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001001endif
1002
Arnd Bergmann877417e2016-04-25 17:35:27 +02001003choice
1004 prompt "Compiler optimization level"
Ulf Magnusson2cc3ce22017-10-04 01:53:26 +02001005 default CC_OPTIMIZE_FOR_PERFORMANCE
Arnd Bergmann877417e2016-04-25 17:35:27 +02001006
1007config CC_OPTIMIZE_FOR_PERFORMANCE
1008 bool "Optimize for performance"
1009 help
1010 This is the default optimization level for the kernel, building
1011 with the "-O2" compiler flag for best performance and most
1012 helpful compile-time warnings.
1013
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001014config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001015 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001016 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001017 Enabling this option will pass "-Os" instead of "-O2" to
1018 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001019
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001020 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001021
Arnd Bergmann877417e2016-04-25 17:35:27 +02001022endchoice
1023
Randy Dunlap08470622006-09-30 23:28:13 -07001024config SYSCTL
1025 bool
1026
Randy Dunlapb943c462009-03-10 12:55:46 -07001027config ANON_INODES
1028 bool
1029
Mike Frysinger657a5202013-04-30 15:28:45 -07001030config HAVE_UID16
1031 bool
1032
1033config SYSCTL_EXCEPTION_TRACE
1034 bool
1035 help
1036 Enable support for /proc/sys/debug/exception-trace.
1037
1038config SYSCTL_ARCH_UNALIGN_NO_WARN
1039 bool
1040 help
1041 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1042 Allows arch to define/use @no_unaligned_warning to possibly warn
1043 about unaligned access emulation going on under the hood.
1044
1045config SYSCTL_ARCH_UNALIGN_ALLOW
1046 bool
1047 help
1048 Enable support for /proc/sys/kernel/unaligned-trap
1049 Allows arches to define/use @unaligned_enabled to runtime toggle
1050 the unaligned access emulation.
1051 see arch/parisc/kernel/unaligned.c for reference
1052
Mike Frysinger657a5202013-04-30 15:28:45 -07001053config HAVE_PCSPKR_PLATFORM
1054 bool
1055
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001056# interpreter that classic socket filters depend on
1057config BPF
1058 bool
1059
David Rientjes6a108a12011-01-20 14:44:16 -08001060menuconfig EXPERT
1061 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001062 # Unhide debug options, to make the on-by-default options visible
1063 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 help
1065 This option allows certain base kernel options and settings
1066 to be disabled or tweaked. This is for specialized
1067 environments which can tolerate a "non-standard" kernel.
1068 Only use this if you really know what you are doing.
1069
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001070config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001071 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001072 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001073 default y
1074 help
1075 This enables the legacy 16-bit UID syscall wrappers.
1076
Iulia Manda28138932015-04-15 16:16:41 -07001077config MULTIUSER
1078 bool "Multiple users, groups and capabilities support" if EXPERT
1079 default y
1080 help
1081 This option enables support for non-root users, groups and
1082 capabilities.
1083
1084 If you say N here, all processes will run with UID 0, GID 0, and all
1085 possible capabilities. Saying N here also compiles out support for
1086 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1087 setgid, and capset.
1088
1089 If unsure, say Y here.
1090
Fabian Frederickf6187762014-06-04 16:11:12 -07001091config SGETMASK_SYSCALL
1092 bool "sgetmask/ssetmask syscalls support" if EXPERT
Arnd Bergmanna687a532018-03-07 23:30:54 +01001093 def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH
Fabian Frederickf6187762014-06-04 16:11:12 -07001094 ---help---
1095 sys_sgetmask and sys_ssetmask are obsolete system calls
1096 no longer supported in libc but still enabled by default in some
1097 architectures.
1098
1099 If unsure, leave the default option here.
1100
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001101config SYSFS_SYSCALL
1102 bool "Sysfs syscall support" if EXPERT
1103 default y
1104 ---help---
1105 sys_sysfs is an obsolete system call no longer supported in libc.
1106 Note that disabling this option is more secure but might break
1107 compatibility with some systems.
1108
1109 If unsure say Y here.
1110
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001111config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001112 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001113 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001114 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001115 select SYSCTL
1116 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001117 sys_sysctl uses binary paths that have been found challenging
1118 to properly maintain and use. The interface in /proc/sys
1119 using paths with ascii names is now the primary path to this
1120 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001121
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001122 Almost nothing using the binary sysctl interface so if you are
1123 trying to save some space it is probably safe to disable this,
1124 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001125
WANG Congc736de62011-11-02 13:39:25 -07001126 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001127
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001128config FHANDLE
1129 bool "open by fhandle syscalls" if EXPERT
1130 select EXPORTFS
1131 default y
1132 help
1133 If you say Y here, a user level program will be able to map
1134 file names to handle and then later use the handle for
1135 different file system operations. This is useful in implementing
1136 userspace file servers, which now track files using handles instead
1137 of names. The handle would remain the same even if file names
1138 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1139 syscalls.
1140
Nicolas Pitrebaa73d92016-11-11 00:10:10 -05001141config POSIX_TIMERS
1142 bool "Posix Clocks & timers" if EXPERT
1143 default y
1144 help
1145 This includes native support for POSIX timers to the kernel.
1146 Some embedded systems have no use for them and therefore they
1147 can be configured out to reduce the size of the kernel image.
1148
1149 When this option is disabled, the following syscalls won't be
1150 available: timer_create, timer_gettime: timer_getoverrun,
1151 timer_settime, timer_delete, clock_adjtime, getitimer,
1152 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1153 clock_getres and clock_nanosleep syscalls will be limited to
1154 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1155
1156 If unsure say y.
1157
Matt Mackalld59745c2005-05-01 08:59:02 -07001158config PRINTK
1159 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001160 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001161 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001162 help
1163 This option enables normal printk support. Removing it
1164 eliminates most of the message strings from the kernel image
1165 and makes the kernel more or less silent. As this makes it
1166 very difficult to diagnose system problems, saying N here is
1167 strongly discouraged.
1168
Petr Mladek42a0bb32016-05-20 17:00:33 -07001169config PRINTK_NMI
1170 def_bool y
1171 depends on PRINTK
1172 depends on HAVE_NMI
1173
Matt Mackallc8538a72005-05-01 08:59:01 -07001174config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001175 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001176 default y
1177 help
1178 Disabling this option eliminates support for BUG and WARN, reducing
1179 the size of your kernel image and potentially quietly ignoring
1180 numerous fatal conditions. You should only consider disabling this
1181 option for embedded systems with no facilities for reporting errors.
1182 Just say Y.
1183
Matt Mackall708e9a72006-01-08 01:05:25 -08001184config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001185 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001186 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001187 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001188 help
1189 Enable support for generating core dumps. Disabling saves about 4k.
1190
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001191
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001192config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001193 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001194 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001195 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001196 default y
1197 help
1198 This option allows to disable the internal PC-Speaker
1199 support, saving some memory.
1200
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201config BASE_FULL
1202 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001203 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 help
1205 Disabling this option reduces the size of miscellaneous core
1206 kernel data structures. This saves memory on small machines,
1207 but may reduce performance.
1208
1209config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001210 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 default y
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001212 imply RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 help
1214 Disabling this option will cause the kernel to be built without
1215 support for "fast userspace mutexes". The resulting kernel may not
1216 run glibc-based applications correctly.
1217
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001218config FUTEX_PI
1219 bool
1220 depends on FUTEX && RT_MUTEXES
1221 default y
1222
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001223config HAVE_FUTEX_CMPXCHG
1224 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001225 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001226 help
1227 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1228 is implemented and always working. This removes a couple of runtime
1229 checks.
1230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001232 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001234 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 help
1236 Disabling this option will cause the kernel to be built without
1237 support for epoll family of system calls.
1238
Davide Libenzifba2afa2007-05-10 22:23:13 -07001239config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001240 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001241 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001242 default y
1243 help
1244 Enable the signalfd() system call that allows to receive signals
1245 on a file descriptor.
1246
1247 If unsure, say Y.
1248
Davide Libenzib215e282007-05-10 22:23:16 -07001249config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001250 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001251 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001252 default y
1253 help
1254 Enable the timerfd() system call that allows to receive timer
1255 events on a file descriptor.
1256
1257 If unsure, say Y.
1258
Davide Libenzie1ad7462007-05-10 22:23:19 -07001259config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001260 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001261 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001262 default y
1263 help
1264 Enable the eventfd() system call that allows to receive both
1265 kernel notification (ie. KAIO) or userspace notifications.
1266
1267 If unsure, say Y.
1268
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001270 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 default y
1272 depends on MMU
1273 help
1274 The shmem is an internal filesystem used to manage shared memory.
1275 It is backed by swap and manages resource limits. It is also exported
1276 to userspace as tmpfs if TMPFS is enabled. Disabling this
1277 option replaces shmem and tmpfs with the much simpler ramfs code,
1278 which may be appropriate on small systems without swap.
1279
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001280config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001281 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001282 default y
1283 help
1284 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001285 by some high performance threaded applications. Disabling
1286 this option saves about 7k.
1287
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001288config ADVISE_SYSCALLS
1289 bool "Enable madvise/fadvise syscalls" if EXPERT
1290 default y
1291 help
1292 This option enables the madvise and fadvise syscalls, used by
1293 applications to advise the kernel about their future memory or file
1294 usage, improving performance. If building an embedded system where no
1295 applications use these syscalls, you can disable this option to save
1296 space.
1297
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001298config MEMBARRIER
1299 bool "Enable membarrier() system call" if EXPERT
1300 default y
1301 help
1302 Enable the membarrier() system call that allows issuing memory
1303 barriers across all running threads, which can be used to distribute
1304 the cost of user-space memory barriers asymmetrically by transforming
1305 pairs of memory barriers into pairs consisting of membarrier() and a
1306 compiler barrier.
1307
1308 If unsure, say Y.
1309
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001310config CHECKPOINT_RESTORE
1311 bool "Checkpoint/restore support" if EXPERT
1312 select PROC_CHILDREN
1313 default n
1314 help
1315 Enables additional kernel features in a sake of checkpoint/restore.
1316 In particular it adds auxiliary prctl codes to setup process text,
1317 data and heap segment sizes, and a few additional /proc filesystem
1318 entries.
1319
1320 If unsure, say N here.
1321
1322config KALLSYMS
1323 bool "Load all symbols for debugging/ksymoops" if EXPERT
1324 default y
1325 help
1326 Say Y here to let the kernel print out symbolic crash information and
1327 symbolic stack backtraces. This increases the size of the kernel
1328 somewhat, as all symbols have to be loaded into the kernel image.
1329
1330config KALLSYMS_ALL
1331 bool "Include all symbols in kallsyms"
1332 depends on DEBUG_KERNEL && KALLSYMS
1333 help
1334 Normally kallsyms only contains the symbols of functions for nicer
1335 OOPS messages and backtraces (i.e., symbols from the text and inittext
1336 sections). This is sufficient for most cases. And only in very rare
1337 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1338 names of variables from the data sections, etc).
1339
1340 This option makes sure that all symbols are loaded into the kernel
1341 image (i.e., symbols from all sections) in cost of increased kernel
1342 size (depending on the kernel configuration, it may be 300KiB or
1343 something like this).
1344
1345 Say N unless you really need all symbols.
1346
1347config KALLSYMS_ABSOLUTE_PERCPU
1348 bool
1349 depends on KALLSYMS
1350 default X86_64 && SMP
1351
1352config KALLSYMS_BASE_RELATIVE
1353 bool
1354 depends on KALLSYMS
Arnd Bergmanna687a532018-03-07 23:30:54 +01001355 default !IA64
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001356 help
1357 Instead of emitting them as absolute values in the native word size,
1358 emit the symbol references in the kallsyms table as 32-bit entries,
1359 each containing a relative value in the range [base, base + U32_MAX]
1360 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1361 an absolute value in the range [0, S32_MAX] or a relative value in the
1362 range [base, base + S32_MAX], where base is the lowest relative symbol
1363 address encountered in the image.
1364
1365 On 64-bit builds, this reduces the size of the address table by 50%,
1366 but more importantly, it results in entries whose values are build
1367 time constants, and no relocation pass is required at runtime to fix
1368 up the entries based on the runtime load address of the kernel.
1369
1370# end of the "standard kernel features (expert users)" menu
1371
1372# syscall, maps, verifier
1373config BPF_SYSCALL
1374 bool "Enable bpf() system call"
1375 select ANON_INODES
1376 select BPF
1377 default n
1378 help
1379 Enable the bpf() system call that allows to manipulate eBPF
1380 programs and maps via file descriptors.
1381
Alexei Starovoitov290af862018-01-09 10:04:29 -08001382config BPF_JIT_ALWAYS_ON
1383 bool "Permanently enable BPF JIT and remove BPF interpreter"
1384 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
1385 help
1386 Enables BPF JIT and removes BPF interpreter to avoid
1387 speculative execution of BPF instructions by the interpreter
1388
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001389config USERFAULTFD
1390 bool "Enable userfaultfd() system call"
1391 select ANON_INODES
1392 depends on MMU
1393 help
1394 Enable the userfaultfd() system call that allows to intercept and
1395 handle page faults in userland.
1396
Mathieu Desnoyers3ccfebe2018-01-29 15:20:11 -05001397config ARCH_HAS_MEMBARRIER_CALLBACKS
1398 bool
1399
Mathieu Desnoyers70216e12018-01-29 15:20:17 -05001400config ARCH_HAS_MEMBARRIER_SYNC_CORE
1401 bool
1402
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001403config EMBEDDED
1404 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001405 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001406 select EXPERT
1407 help
1408 This option should be enabled if compiling the kernel for
1409 an embedded system so certain expert options are available
1410 for configuration.
1411
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001412config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001413 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001414 help
1415 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001416
Peter Zijlstra906010b2009-09-21 16:08:49 +02001417config PERF_USE_VMALLOC
1418 bool
1419 help
1420 See tools/perf/design.txt for details
1421
William Breathitt Grayad90a3d2017-01-10 13:50:54 -05001422config PC104
William Breathitt Gray424529f2017-12-29 15:14:59 -05001423 bool "PC/104 support" if EXPERT
William Breathitt Grayad90a3d2017-01-10 13:50:54 -05001424 help
1425 Expose PC/104 form factor device drivers and options available for
1426 selection and configuration. Enable this option if your target
1427 machine has a PC/104 bus.
1428
Ingo Molnar57c0c152009-09-21 12:20:38 +02001429menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001430
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001431config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001432 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001433 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001434 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001435 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001436 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001437 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001438 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001439 Enable kernel support for various performance events provided
1440 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001441
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001442 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001443 use of generic tracepoints.
1444
1445 Most modern CPUs support performance events via performance
1446 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001447 types of hw events: such as instructions executed, cachemisses
1448 suffered, or branches mis-predicted - without slowing down the
1449 kernel or applications. These registers can also trigger interrupts
1450 when a threshold number of events have passed - and can thus be
1451 used to profile the code that runs on that CPU.
1452
Ingo Molnar57c0c152009-09-21 12:20:38 +02001453 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001454 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001455 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001456 provides per task and per CPU counters, and it provides event
1457 capabilities on top of those.
1458
1459 Say Y if unsure.
1460
Peter Zijlstra906010b2009-09-21 16:08:49 +02001461config DEBUG_PERF_USE_VMALLOC
1462 default n
1463 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001464 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001465 select PERF_USE_VMALLOC
1466 help
1467 Use vmalloc memory to back perf mmap() buffers.
1468
1469 Mostly useful for debugging the vmalloc code on platforms
1470 that don't require it.
1471
1472 Say N if unsure.
1473
Thomas Gleixner0793a612008-12-04 20:12:29 +01001474endmenu
1475
Christoph Lameterf8891e52006-06-30 01:55:45 -07001476config VM_EVENT_COUNTERS
1477 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001478 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001479 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001480 VM event counters are needed for event counts to be shown.
1481 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001482 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001483 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001484
Christoph Lameter41ecc552007-05-09 02:32:44 -07001485config SLUB_DEBUG
1486 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001487 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001488 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001489 help
1490 SLUB has extensive debug support features. Disabling these can
1491 result in significant savings in code size. This also disables
1492 SLUB sysfs support. /sys/slab will not exist and there will be
1493 no support for cache validation etc.
1494
Tejun Heo1663f262017-02-22 15:41:39 -08001495config SLUB_MEMCG_SYSFS_ON
1496 default n
1497 bool "Enable memcg SLUB sysfs support by default" if EXPERT
1498 depends on SLUB && SYSFS && MEMCG
1499 help
1500 SLUB creates a directory under /sys/kernel/slab for each
1501 allocation cache to host info and debug files. If memory
1502 cgroup is enabled, each cache can have per memory cgroup
1503 caches. SLUB can create the same sysfs directories for these
1504 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
1505 to a very high number of debug files being created. This is
1506 controlled by slub_memcg_sysfs boot parameter and this
1507 config option determines the parameter's default value.
1508
Randy Dunlapb943c462009-03-10 12:55:46 -07001509config COMPAT_BRK
1510 bool "Disable heap randomization"
1511 default y
1512 help
1513 Randomizing heap placement makes heap exploits harder, but it
1514 also breaks ancient binaries (including anything libc5 based).
1515 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001516 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001517 /proc/sys/kernel/randomize_va_space to 2.
1518
1519 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1520
Christoph Lameter81819f02007-05-06 14:49:36 -07001521choice
1522 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001523 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001524 help
1525 This option allows to select a slab allocator.
1526
1527config SLAB
1528 bool "SLAB"
Kees Cook04385fc2016-06-23 15:20:59 -07001529 select HAVE_HARDENED_USERCOPY_ALLOCATOR
Christoph Lameter81819f02007-05-06 14:49:36 -07001530 help
1531 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001532 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001533 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001534
1535config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001536 bool "SLUB (Unqueued Allocator)"
Kees Cooked18adc2016-06-23 15:24:05 -07001537 select HAVE_HARDENED_USERCOPY_ALLOCATOR
Christoph Lameter81819f02007-05-06 14:49:36 -07001538 help
1539 SLUB is a slab allocator that minimizes cache line usage
1540 instead of managing queues of cached objects (SLAB approach).
1541 Per cpu caching is realized using slabs of objects instead
1542 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001543 and has enhanced diagnostics. SLUB is the default choice for
1544 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001545
1546config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001547 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001548 bool "SLOB (Simple Allocator)"
1549 help
Matt Mackall37291452008-02-04 22:29:38 -08001550 SLOB replaces the stock allocator with a drastically simpler
1551 allocator. SLOB is generally more space efficient but
1552 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001553
1554endchoice
1555
Kees Cook7660a6f2017-07-06 15:36:40 -07001556config SLAB_MERGE_DEFAULT
1557 bool "Allow slab caches to be merged"
1558 default y
1559 help
1560 For reduced kernel memory fragmentation, slab caches can be
1561 merged when they share the same size and other characteristics.
1562 This carries a risk of kernel heap overflows being able to
1563 overwrite objects from merged caches (and more easily control
1564 cache layout), which makes such heap attacks easier to exploit
1565 by attackers. By keeping caches unmerged, these kinds of exploits
1566 can usually only damage objects in the same cache. To disable
1567 merging at runtime, "slab_nomerge" can be passed on the kernel
1568 command line.
1569
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001570config SLAB_FREELIST_RANDOM
1571 default n
Thomas Garnier210e7a42016-07-26 15:21:59 -07001572 depends on SLAB || SLUB
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001573 bool "SLAB freelist randomization"
1574 help
Thomas Garnier210e7a42016-07-26 15:21:59 -07001575 Randomizes the freelist order used on creating new pages. This
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001576 security feature reduces the predictability of the kernel slab
1577 allocator against heap overflows.
1578
Kees Cook2482dde2017-09-06 16:19:18 -07001579config SLAB_FREELIST_HARDENED
1580 bool "Harden slab freelist metadata"
1581 depends on SLUB
1582 help
1583 Many kernel heap attacks try to target slab cache metadata and
1584 other infrastructure. This options makes minor performance
1585 sacrifies to harden the kernel slab allocator against common
1586 freelist exploit methods.
1587
Joonsoo Kim345c9052013-06-19 14:05:52 +09001588config SLUB_CPU_PARTIAL
1589 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001590 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001591 bool "SLUB per cpu partial cache"
1592 help
1593 Per cpu partial caches accellerate objects allocation and freeing
1594 that is local to a processor at the price of more indeterminism
1595 in the latency of the free. On overflow these caches will be cleared
1596 which requires the taking of locks that may cause latency spikes.
1597 Typically one would choose no for a realtime system.
1598
Jie Zhangea637632009-12-14 18:00:02 -08001599config MMAP_ALLOW_UNINITIALIZED
1600 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001601 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001602 default n
1603 help
1604 Normally, and according to the Linux spec, anonymous memory obtained
1605 from mmap() has it's contents cleared before it is passed to
1606 userspace. Enabling this config option allows you to request that
1607 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1608 providing a huge performance boost. If this option is not enabled,
1609 then the flag will be ignored.
1610
1611 This is taken advantage of by uClibc's malloc(), and also by
1612 ELF-FDPIC binfmt's brk and stack allocator.
1613
1614 Because of the obvious security issues, this option should only be
1615 enabled on embedded devices where you control what is run in
1616 userspace. Since that isn't generally a problem on no-MMU systems,
1617 it is normally safe to say Y here.
1618
1619 See Documentation/nommu-mmap.txt for more information.
1620
David Howells091f6e22015-07-20 21:16:28 +01001621config SYSTEM_DATA_VERIFICATION
1622 def_bool n
1623 select SYSTEM_TRUSTED_KEYRING
1624 select KEYS
1625 select CRYPTO
David Howellsd43de6c2016-03-03 21:49:27 +00001626 select CRYPTO_RSA
David Howells091f6e22015-07-20 21:16:28 +01001627 select ASYMMETRIC_KEY_TYPE
1628 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
David Howells091f6e22015-07-20 21:16:28 +01001629 select ASN1
1630 select OID_REGISTRY
1631 select X509_CERTIFICATE_PARSER
1632 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001633 help
David Howells091f6e22015-07-20 21:16:28 +01001634 Provide PKCS#7 message verification using the contents of the system
1635 trusted keyring to provide public keys. This then can be used for
1636 module verification, kexec image verification and firmware blob
1637 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001638
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001639config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001640 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001641 help
1642 Say Y here to enable the extended profiling support mechanisms used
1643 by profilers such as OProfile.
1644
Ingo Molnar5f87f112008-07-23 14:15:22 +02001645#
1646# Place an empty function call at each tracepoint site. Can be
1647# dynamically changed for a probe function.
1648#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001649config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001650 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001651
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001652source "arch/Kconfig"
1653
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654endmenu # General setup
1655
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001656config HAVE_GENERIC_DMA_COHERENT
1657 bool
1658 default n
1659
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001660config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001661 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001662
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663config BASE_SMALL
1664 int
1665 default 0 if BASE_FULL
1666 default 1 if !BASE_FULL
1667
Jan Engelhardt66da5732007-07-15 23:39:29 -07001668menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001670 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671 help
1672 Kernel modules are small pieces of compiled code which can
1673 be inserted in the running kernel, rather than being
1674 permanently built into the kernel. You use the "modprobe"
1675 tool to add (and sometimes remove) them. If you say Y here,
1676 many parts of the kernel can be built as modules (by
1677 answering M instead of Y where indicated): this is most
1678 useful for infrequently used options which are not required
1679 for booting. For more information, see the man pages for
1680 modprobe, lsmod, modinfo, insmod and rmmod.
1681
1682 If you say Y here, you will need to run "make
1683 modules_install" to put the modules under /lib/modules/
1684 where modprobe can find them (you may need to be root to do
1685 this).
1686
1687 If unsure, say Y.
1688
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001689if MODULES
1690
Linus Torvalds826e4502008-05-04 17:04:16 -07001691config MODULE_FORCE_LOAD
1692 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001693 default n
1694 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001695 Allow loading of modules without version information (ie. modprobe
1696 --force). Forced module loading sets the 'F' (forced) taint flag and
1697 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001698
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699config MODULE_UNLOAD
1700 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 help
1702 Without this option you will not be able to unload any
1703 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001704 anyway), which makes your kernel smaller, faster
1705 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706
1707config MODULE_FORCE_UNLOAD
1708 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001709 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 help
1711 This option allows you to force a module to unload, even if the
1712 kernel believes it is unsafe: the kernel will remove the module
1713 without waiting for anyone to stop using it (using the -f option to
1714 rmmod). This is mainly for kernel developers and desperate users.
1715 If unsure, say N.
1716
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001718 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 help
1720 Usually, you have to use modules compiled with your kernel.
1721 Saying Y here makes it sometimes possible to use modules
1722 compiled for different kernels, by adding enough information
1723 to the modules to (hopefully) spot any changes which would
1724 make them incompatible with the kernel you are running. If
1725 unsure, say N.
1726
Ard Biesheuvel56067812017-02-03 09:54:05 +00001727config MODULE_REL_CRCS
1728 bool
1729 depends on MODVERSIONS
1730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731config MODULE_SRCVERSION_ALL
1732 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 help
1734 Modules which contain a MODULE_VERSION get an extra "srcversion"
1735 field inserted into their modinfo section, which contains a
1736 sum of the source files which made it. This helps maintainers
1737 see exactly which source was used to build a module (since
1738 others sometimes change the module source without updating
1739 the version). With this option, such a "srcversion" field
1740 will be created for all modules. If unsure, say N.
1741
Rusty Russell106a4ee2012-09-26 10:09:40 +01001742config MODULE_SIG
1743 bool "Module signature verification"
1744 depends on MODULES
David Howells091f6e22015-07-20 21:16:28 +01001745 select SYSTEM_DATA_VERIFICATION
Rusty Russell106a4ee2012-09-26 10:09:40 +01001746 help
1747 Check modules for valid signatures upon load: the signature
1748 is simply appended to the module. For more information see
Nathan Chancellorcbdc8212017-09-10 02:48:29 -07001749 <file:Documentation/admin-guide/module-signing.rst>.
Rusty Russell106a4ee2012-09-26 10:09:40 +01001750
David Howells228c37f2015-08-11 12:38:54 +01001751 Note that this option adds the OpenSSL development packages as a
1752 kernel build dependency so that the signing tool can use its crypto
1753 library.
1754
David Howellsea0b6dc2012-09-26 10:09:50 +01001755 !!!WARNING!!! If you enable this option, you MUST make sure that the
1756 module DOES NOT get stripped after being signed. This includes the
1757 debuginfo strip done by some packagers (such as rpmbuild) and
1758 inclusion into an initramfs that wants the module size reduced.
1759
Rusty Russell106a4ee2012-09-26 10:09:40 +01001760config MODULE_SIG_FORCE
1761 bool "Require modules to be validly signed"
1762 depends on MODULE_SIG
1763 help
1764 Reject unsigned modules or signed modules for which we don't have a
1765 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001766
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301767config MODULE_SIG_ALL
1768 bool "Automatically sign all modules"
1769 default y
1770 depends on MODULE_SIG
1771 help
1772 Sign all modules during make modules_install. Without this option,
1773 modules must be signed manually, using the scripts/sign-file tool.
1774
1775comment "Do not forget to sign required modules with scripts/sign-file"
1776 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1777
David Howellsea0b6dc2012-09-26 10:09:50 +01001778choice
1779 prompt "Which hash algorithm should modules be signed with?"
1780 depends on MODULE_SIG
1781 help
1782 This determines which sort of hashing algorithm will be used during
1783 signature generation. This algorithm _must_ be built into the kernel
1784 directly so that signature verification can take place. It is not
1785 possible to load a signed module containing the algorithm to check
1786 the signature on that module.
1787
1788config MODULE_SIG_SHA1
1789 bool "Sign modules with SHA-1"
1790 select CRYPTO_SHA1
1791
1792config MODULE_SIG_SHA224
1793 bool "Sign modules with SHA-224"
1794 select CRYPTO_SHA256
1795
1796config MODULE_SIG_SHA256
1797 bool "Sign modules with SHA-256"
1798 select CRYPTO_SHA256
1799
1800config MODULE_SIG_SHA384
1801 bool "Sign modules with SHA-384"
1802 select CRYPTO_SHA512
1803
1804config MODULE_SIG_SHA512
1805 bool "Sign modules with SHA-512"
1806 select CRYPTO_SHA512
1807
1808endchoice
1809
Michal Marek22753672013-01-25 13:41:00 +10301810config MODULE_SIG_HASH
1811 string
1812 depends on MODULE_SIG
1813 default "sha1" if MODULE_SIG_SHA1
1814 default "sha224" if MODULE_SIG_SHA224
1815 default "sha256" if MODULE_SIG_SHA256
1816 default "sha384" if MODULE_SIG_SHA384
1817 default "sha512" if MODULE_SIG_SHA512
1818
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301819config MODULE_COMPRESS
1820 bool "Compress modules on installation"
1821 depends on MODULES
1822 help
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301823
Rusty Russellb6c09b52015-06-16 12:16:22 +09301824 Compresses kernel modules when 'make modules_install' is run; gzip or
1825 xz depending on "Compression algorithm" below.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301826
Rusty Russellb6c09b52015-06-16 12:16:22 +09301827 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301828
Rusty Russellb6c09b52015-06-16 12:16:22 +09301829 Out-of-tree kernel modules installed using Kbuild will also be
1830 compressed upon installation.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301831
Rusty Russellb6c09b52015-06-16 12:16:22 +09301832 Note: for modules inside an initrd or initramfs, it's more efficient
1833 to compress the whole initrd or initramfs instead.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301834
Rusty Russellb6c09b52015-06-16 12:16:22 +09301835 Note: This is fully compatible with signed modules.
1836
1837 If in doubt, say N.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301838
1839choice
1840 prompt "Compression algorithm"
1841 depends on MODULE_COMPRESS
1842 default MODULE_COMPRESS_GZIP
1843 help
1844 This determines which sort of compression will be used during
1845 'make modules_install'.
1846
1847 GZIP (default) and XZ are supported.
1848
1849config MODULE_COMPRESS_GZIP
1850 bool "GZIP"
1851
1852config MODULE_COMPRESS_XZ
1853 bool "XZ"
1854
1855endchoice
1856
Nicolas Pitredbacb0e2016-01-26 21:51:05 -05001857config TRIM_UNUSED_KSYMS
1858 bool "Trim unused exported kernel symbols"
1859 depends on MODULES && !UNUSED_SYMBOLS
1860 help
1861 The kernel and some modules make many symbols available for
1862 other modules to use via EXPORT_SYMBOL() and variants. Depending
1863 on the set of modules being selected in your kernel configuration,
1864 many of those exported symbols might never be used.
1865
1866 This option allows for unused exported symbols to be dropped from
1867 the build. In turn, this provides the compiler more opportunities
1868 (especially when using LTO) for optimizing the code and reducing
1869 binary size. This might have some security advantages as well.
1870
Valdis Kletnieksf1cb6372016-08-02 14:07:27 -07001871 If unsure, or if you need to build out-of-tree modules, say N.
Nicolas Pitredbacb0e2016-01-26 21:51:05 -05001872
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001873endif # MODULES
1874
Peter Zijlstra6c9692e2015-05-27 11:09:37 +09301875config MODULES_TREE_LOOKUP
1876 def_bool y
1877 depends on PERF_EVENTS || TRACING
1878
Rusty Russell98a79d62008-12-13 21:19:41 +10301879config INIT_ALL_POSSIBLE
1880 bool
1881 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301882 Back when each arch used to define their own cpu_online_mask and
1883 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301884 with all 1s, and others with all 0s. When they were centralised,
1885 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001886 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301887
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001888source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001889
1890config PREEMPT_NOTIFIERS
1891 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001892
Steffen Klassert16295be2010-01-06 19:47:10 +11001893config PADATA
1894 depends on SMP
1895 bool
1896
David Howells4520c6a2012-09-21 23:31:13 +01001897config ASN1
1898 tristate
1899 help
1900 Build a simple ASN.1 grammar compiler that produces a bytecode output
1901 that can be interpreted by the ASN.1 stream decoder and used to
1902 inform it as to what tags are to be expected in a stream and what
1903 functions to call on what tags.
1904
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001905source "kernel/Kconfig.locks"
Mathieu Desnoyerse61938a2018-01-29 15:20:15 -05001906
1907config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
1908 bool
Dominik Brodowski1bd21c62018-04-05 11:53:01 +02001909
1910# It may be useful for an architecture to override the definitions of the
Dominik Brodowski7303e302018-04-05 11:53:03 +02001911# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
1912# and the COMPAT_ variants in <linux/compat.h>, in particular to use a
1913# different calling convention for syscalls. They can also override the
1914# macros for not-implemented syscalls in kernel/sys_ni.c and
1915# kernel/time/posix-stubs.c. All these overrides need to be available in
1916# <asm/syscall_wrapper.h>.
Dominik Brodowski1bd21c62018-04-05 11:53:01 +02001917config ARCH_HAS_SYSCALL_WRAPPER
1918 def_bool n