blob: e37f4b2a64453bc30d7b84c550043d0f678d8634 [file] [log] [blame]
Roman Zippel80daa562008-01-14 04:51:16 +01001config ARCH
2 string
3 option env="ARCH"
4
5config KERNELVERSION
6 string
7 option env="KERNELVERSION"
8
Roman Zippelface4372006-06-08 22:12:45 -07009config DEFCONFIG_LIST
10 string
Paolo 'Blaisorblade' Giarrussob2670eac2006-10-19 23:28:23 -070011 depends on !UML
Roman Zippelface4372006-06-08 22:12:45 -070012 option defconfig_list
13 default "/lib/modules/$UNAME_RELEASE/.config"
14 default "/etc/kernel-config"
15 default "/boot/config-$UNAME_RELEASE"
Sam Ravnborg73531902008-05-25 23:03:18 +020016 default "$ARCH_DEFCONFIG"
Roman Zippelface4372006-06-08 22:12:45 -070017 default "arch/$ARCH/defconfig"
18
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070019config CONSTRUCTORS
20 bool
21 depends on !UML
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -070022
Peter Zijlstrae360adb2010-10-14 14:01:34 +080023config IRQ_WORK
24 bool
Peter Zijlstrae360adb2010-10-14 14:01:34 +080025
David Daney1dbdc6f2012-04-19 14:59:57 -070026config BUILDTIME_EXTABLE_SORT
27 bool
28
Andy Lutomirskic65eacb2016-09-13 14:29:24 -070029config THREAD_INFO_IN_TASK
30 bool
31 help
32 Select this to move thread_info off the stack into task_struct. To
33 make this work, an arch will need to remove all thread_info fields
34 except flags and fix any runtime bugs.
35
Andy Lutomirskic6c314a2016-09-15 22:45:43 -070036 One subtle change that will be needed is to use try_get_task_stack()
37 and put_task_stack() in save_thread_stack_tsk() and get_wchan().
38
Al Boldiff0cfc62007-07-31 00:39:23 -070039menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Linus Torvalds1da177e2005-04-16 15:20:36 -070041config BROKEN
42 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44config BROKEN_ON_SMP
45 bool
46 depends on BROKEN || !SMP
47 default y
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049config INIT_ENV_ARG_LIMIT
50 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070051 default 32 if !UML
52 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080054 Maximum of each of the number of arguments and environment
55 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Roland McGrath84336462009-12-21 16:24:06 -080058config CROSS_COMPILE
59 string "Cross-compiler tool prefix"
60 help
61 Same as running 'make CROSS_COMPILE=prefix-' but stored for
62 default make runs in this kernel build directory. You don't
63 need to set this unless you want the configured kernel build
64 directory to select the cross-compiler automatically.
65
Jiri Slaby4bb16672013-05-22 10:56:24 +020066config COMPILE_TEST
67 bool "Compile also drivers which will not load"
Richard Weinbergerbc083a62016-08-02 14:03:27 -070068 depends on !UML
Jiri Slaby4bb16672013-05-22 10:56:24 +020069 default n
70 help
71 Some drivers can be compiled on a different platform than they are
72 intended to be run on. Despite they cannot be loaded there (or even
73 when they load they cannot be used due to missing HW support),
74 developers still, opposing to distributors, might want to build such
75 drivers to compile-test them.
76
77 If you are a developer and want to build everything available, say Y
78 here. If you are a user/distributor, say N here to exclude useless
79 drivers to be distributed.
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081config LOCALVERSION
82 string "Local version - append to kernel release"
83 help
84 Append an extra string to the end of your kernel version.
85 This will show up when you type uname, for example.
86 The string you set here will be appended after the contents of
87 any files with a filename matching localversion* in your
88 object and source tree, in that order. Your total string can
89 be a maximum of 64 characters.
90
Ryan Andersonaaebf432005-07-31 04:57:49 -040091config LOCALVERSION_AUTO
92 bool "Automatically append version information to the version string"
93 default y
Alexey Dobriyanac3339b2016-08-02 14:07:21 -070094 depends on !COMPILE_TEST
Ryan Andersonaaebf432005-07-31 04:57:49 -040095 help
96 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020097 release tree by looking for git tags that belong to the current
98 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040099
100 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200101 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -0400102 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200103 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -0400104
Robert P. J. Day6e5a5422007-05-01 23:08:11 +0200105 (The actual string used here is the first eight characters produced
106 by running the command:
107
108 $ git rev-parse --verify HEAD
109
110 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -0400111
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800112config HAVE_KERNEL_GZIP
113 bool
114
115config HAVE_KERNEL_BZIP2
116 bool
117
118config HAVE_KERNEL_LZMA
119 bool
120
Lasse Collin3ebe1242011-01-12 17:01:23 -0800121config HAVE_KERNEL_XZ
122 bool
123
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800124config HAVE_KERNEL_LZO
125 bool
126
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700127config HAVE_KERNEL_LZ4
128 bool
129
Alain Knaff30d65db2009-01-04 22:46:17 +0100130choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800131 prompt "Kernel compression mode"
132 default KERNEL_GZIP
H. Peter Anvin2d3c6272013-11-14 21:43:47 -0800133 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 -0800134 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100135 The linux kernel is a kind of self-extracting executable.
136 Several compression algorithms are available, which differ
137 in efficiency, compression and decompression speed.
138 Compression speed is only relevant when building a kernel.
139 Decompression speed is relevant at each boot.
140
141 If you have any problems with bzip2 or lzma compressed
142 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
143 version of this functionality (bzip2 only), for 2.4, was
144 supplied by Christian Ludwig)
145
146 High compression options are mostly useful for users, who
147 are low on disk space (embedded systems), but for whom ram
148 size matters less.
149
150 If in doubt, select 'gzip'
151
152config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800153 bool "Gzip"
154 depends on HAVE_KERNEL_GZIP
155 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800156 The old and tried gzip compression. It provides a good balance
157 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100158
159config KERNEL_BZIP2
160 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800161 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100162 help
163 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700164 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800165 size is about 10% smaller with bzip2, in comparison to gzip.
166 Bzip2 uses a large amount of memory. For modern kernels you
167 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100168
169config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800170 bool "LZMA"
171 depends on HAVE_KERNEL_LZMA
172 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700173 This compression algorithm's ratio is best. Decompression speed
174 is between gzip and bzip2. Compression is slowest.
175 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100176
Lasse Collin3ebe1242011-01-12 17:01:23 -0800177config KERNEL_XZ
178 bool "XZ"
179 depends on HAVE_KERNEL_XZ
180 help
181 XZ uses the LZMA2 algorithm and instruction set specific
182 BCJ filters which can improve compression ratio of executable
183 code. The size of the kernel is about 30% smaller with XZ in
184 comparison to gzip. On architectures for which there is a BCJ
185 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
186 will create a few percent smaller kernel than plain LZMA.
187
188 The speed is about the same as with LZMA: The decompression
189 speed of XZ is better than that of bzip2 but worse than gzip
190 and LZO. Compression is slow.
191
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800192config KERNEL_LZO
193 bool "LZO"
194 depends on HAVE_KERNEL_LZO
195 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700196 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200197 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800198 (both compression and decompression) is the fastest.
199
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700200config KERNEL_LZ4
201 bool "LZ4"
202 depends on HAVE_KERNEL_LZ4
203 help
204 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
205 A preliminary version of LZ4 de/compression tool is available at
206 <https://code.google.com/p/lz4/>.
207
208 Its compression ratio is worse than LZO. The size of the kernel
209 is about 8% bigger than LZO. But the decompression speed is
210 faster than LZO.
211
Alain Knaff30d65db2009-01-04 22:46:17 +0100212endchoice
213
Josh Triplettbd5dc172011-06-15 15:08:28 -0700214config DEFAULT_HOSTNAME
215 string "Default hostname"
216 default "(none)"
217 help
218 This option determines the default system hostname before userspace
219 calls sethostname(2). The kernel traditionally uses "(none)" here,
220 but you may wish to use a different default here to make a minimal
221 system more usable with less configuration.
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223config SWAP
224 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200225 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 default y
227 help
228 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100229 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 used to provide more virtual memory than the actual RAM present
231 in your computer. If unsure say Y.
232
233config SYSVIPC
234 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 ---help---
236 Inter Process Communication is a suite of library functions and
237 system calls which let processes (running programs) synchronize and
238 exchange information. It is generally considered to be a good thing,
239 and some programs won't run unless you say Y here. In particular, if
240 you want to run the DOS emulator dosemu under Linux (read the
241 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
242 you'll need to say Y here.
243
244 You can find documentation about IPC with "info ipc" and also in
245 section 6.4 of the Linux Programmer's Guide, available from
246 <http://www.tldp.org/guides.html>.
247
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800248config SYSVIPC_SYSCTL
249 bool
250 depends on SYSVIPC
251 depends on SYSCTL
252 default y
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254config POSIX_MQUEUE
255 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700256 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 ---help---
258 POSIX variant of message queues is a part of IPC. In POSIX message
259 queues every message has a priority which decides about succession
260 of receiving it by a process. If you want to compile and run
261 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200262 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264 POSIX message queues are visible as a filesystem called 'mqueue'
265 and can be mounted somewhere if you want to do filesystem
266 operations on message queues.
267
268 If unsure, say Y.
269
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700270config POSIX_MQUEUE_SYSCTL
271 bool
272 depends on POSIX_MQUEUE
273 depends on SYSCTL
274 default y
275
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700276config CROSS_MEMORY_ATTACH
277 bool "Enable process_vm_readv/writev syscalls"
278 depends on MMU
279 default y
280 help
281 Enabling this option adds the system calls process_vm_readv and
282 process_vm_writev which allow a process with the correct privileges
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700283 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700284 See the man page for more details.
285
Josh Triplett69369a72014-04-03 14:48:27 -0700286config USELIB
287 bool "uselib syscall"
Riku Voipiob2113a42016-01-15 16:58:13 -0800288 def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION
Josh Triplett69369a72014-04-03 14:48:27 -0700289 help
290 This option enables the uselib syscall, a system call used in the
291 dynamic linker from libc5 and earlier. glibc does not use this
292 system call. If you intend to run programs built on libc5 or
293 earlier, you may need to enable this syscall. Current systems
294 running glibc can safely disable this.
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296config AUDIT
297 bool "Auditing support"
Chris Wright804a6a492005-05-11 10:52:45 +0100298 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 help
300 Enable auditing infrastructure that can be used with another
301 kernel subsystem, such as SELinux (which requires this for
Paul Moorecb74ed22016-01-13 09:18:55 -0500302 logging of avc messages output). System call auditing is included
303 on architectures which support it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900305config HAVE_ARCH_AUDITSYSCALL
306 bool
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308config AUDITSYSCALL
Paul Moorecb74ed22016-01-13 09:18:55 -0500309 def_bool y
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
Eric Paris939a67f2009-12-17 20:12:06 -0500312config AUDIT_WATCH
313 def_bool y
314 depends on AUDITSYSCALL
315 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Al Viro74c3cbe2007-07-22 08:04:18 -0400317config AUDIT_TREE
318 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400319 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500320 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400321
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000322source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200323source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000324
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200325menu "CPU/Task time and stats accounting"
326
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200327config VIRT_CPU_ACCOUNTING
328 bool
329
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200330choice
331 prompt "Cputime accounting"
332 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100333 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200334
335# Kind of a stub config for the pure tick based cputime accounting
336config TICK_CPU_ACCOUNTING
337 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200338 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200339 help
340 This is the basic tick based cputime accounting that maintains
341 statistics about user, system and idle time spent on per jiffies
342 granularity.
343
344 If unsure, say Y.
345
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200346config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200347 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200348 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200349 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200350 help
351 Select this option to enable more accurate task and CPU time
352 accounting. This is done by reading a CPU counter on each
353 kernel entry and exit and on transitions within the kernel
354 between system, softirq and hardirq state, so there is a
355 small performance impact. In the case of s390 or IBM POWER > 5,
356 this also enables accounting of stolen time on logically-partitioned
357 systems.
358
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200359config VIRT_CPU_ACCOUNTING_GEN
360 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700361 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700362 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200363 select VIRT_CPU_ACCOUNTING
364 select CONTEXT_TRACKING
365 help
366 Select this option to enable task and CPU time accounting on full
367 dynticks systems. This accounting is implemented by watching every
368 kernel-user boundaries using the context tracking subsystem.
369 The accounting is thus performed at the expense of some significant
370 overhead.
371
372 For now this is only useful if you are working on the full
373 dynticks subsystem development.
374
375 If unsure, say N.
376
Rik van Rielb58c3582016-07-13 16:50:02 +0200377endchoice
378
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200379config IRQ_TIME_ACCOUNTING
380 bool "Fine granularity task level IRQ time accounting"
Rik van Rielb58c3582016-07-13 16:50:02 +0200381 depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200382 help
383 Select this option to enable fine granularity task irq time
384 accounting. This is done by reading a timestamp on each
385 transitions between softirq and hardirq state, so there can be a
386 small performance impact.
387
388 If in doubt, say N here.
389
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200390config BSD_PROCESS_ACCT
391 bool "BSD Process Accounting"
Iulia Manda28138932015-04-15 16:16:41 -0700392 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200393 help
394 If you say Y here, a user level program will be able to instruct the
395 kernel (via a special system call) to write process accounting
396 information to a file: whenever a process exits, information about
397 that process will be appended to the file by the kernel. The
398 information includes things such as creation time, owning user,
399 command name, memory usage, controlling terminal etc. (the complete
400 list is in the struct acct in <file:include/linux/acct.h>). It is
401 up to the user level program to do useful things with this
402 information. This is generally a good idea, so say Y.
403
404config BSD_PROCESS_ACCT_V3
405 bool "BSD Process Accounting version 3 file format"
406 depends on BSD_PROCESS_ACCT
407 default n
408 help
409 If you say Y here, the process accounting information is written
410 in a new file format that also logs the process IDs of each
411 process and it's parent. Note that this file format is incompatible
412 with previous v0/v1/v2 file formats, so you will need updated tools
413 for processing it. A preliminary version of these tools is available
414 at <http://www.gnu.org/software/acct/>.
415
416config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700417 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200418 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700419 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200420 default n
421 help
422 Export selected statistics for tasks/processes through the
423 generic netlink interface. Unlike BSD process accounting, the
424 statistics are available during the lifetime of tasks/processes as
425 responses to commands. Like BSD accounting, they are sent to user
426 space on task exit.
427
428 Say N if unsure.
429
430config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700431 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200432 depends on TASKSTATS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530433 select SCHED_INFO
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200434 help
435 Collect information on time spent by a task waiting for system
436 resources like cpu, synchronous block I/O completion and swapping
437 in pages. Such statistics can help in setting a task's priorities
438 relative to other tasks for cpu, io, rss limits etc.
439
440 Say N if unsure.
441
442config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700443 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200444 depends on TASKSTATS
445 help
446 Collect extended task accounting data and send the data
447 to userland for processing over the taskstats interface.
448
449 Say N if unsure.
450
451config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700452 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200453 depends on TASK_XACCT
454 help
455 Collect information on the number of bytes of storage I/O which this
456 task has caused.
457
458 Say N if unsure.
459
460endmenu # "CPU/Task time and stats accounting"
461
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200462config CPU_ISOLATION
463 bool "CPU isolation"
Geert Uytterhoeven414a2dc2018-01-02 12:13:10 +0100464 depends on SMP || COMPILE_TEST
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100465 default y
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200466 help
467 Make sure that CPUs running critical tasks are not disturbed by
468 any source of "noise" such as unbound workqueues, timers, kthreads...
Frederic Weisbecker2c438382017-12-14 19:18:26 +0100469 Unbound jobs get offloaded to housekeeping CPUs. This is driven by
470 the "isolcpus=" boot parameter.
471
472 Say Y if unsure.
Frederic Weisbecker5c4991e2017-10-27 04:42:34 +0200473
Paul E. McKenney0af92d42017-05-17 08:43:40 -0700474source "kernel/rcu/Kconfig"
Mike Travisc903ff82009-01-15 12:28:29 -0800475
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700476config BUILD_BIN2C
477 bool
478 default n
479
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700481 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700482 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 ---help---
484 This option enables the complete Linux kernel ".config" file
485 contents to be saved in the kernel. It provides documentation
486 of which kernel options are used in a running kernel or in an
487 on-disk kernel. This information can be extracted from the kernel
488 image file with the script scripts/extract-ikconfig and used as
489 input to rebuild the current kernel or to build another kernel.
490 It can also be extracted from a running kernel by reading
491 /proc/config.gz if enabled (below).
492
493config IKCONFIG_PROC
494 bool "Enable access to .config through /proc/config.gz"
495 depends on IKCONFIG && PROC_FS
496 ---help---
497 This option enables access to the kernel configuration file
498 through /proc/config.gz.
499
Alistair John Strachan794543a2007-05-08 00:31:15 -0700500config LOG_BUF_SHIFT
501 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Ingo Molnarfb39f982015-07-01 10:19:11 +0200502 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700503 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700504 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700505 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700506 Select the minimal kernel log buffer size as a power of 2.
507 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
508 parameter, see below. Any higher size also might be forced
509 by "log_buf_len" boot parameter.
510
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700511 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700512 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700513 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700514 15 => 32 KB
515 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700516 13 => 8 KB
517 12 => 4 KB
518
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700519config LOG_CPU_MAX_BUF_SHIFT
520 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700521 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700522 range 0 21
523 default 12 if !BASE_SMALL
524 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700525 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700526 help
527 This option allows to increase the default ring buffer size
528 according to the number of CPUs. The value defines the contribution
529 of each CPU as a power of 2. The used space is typically only few
530 lines however it might be much more when problems are reported,
531 e.g. backtraces.
532
533 The increased size means that a new buffer has to be allocated and
534 the original static one is unused. It makes sense only on systems
535 with more CPUs. Therefore this value is used only when the sum of
536 contributions is greater than the half of the default kernel ring
537 buffer as defined by LOG_BUF_SHIFT. The default values are set
538 so that more than 64 CPUs are needed to trigger the allocation.
539
540 Also this option is ignored when "log_buf_len" kernel parameter is
541 used as it forces an exact (power of two) size of the ring buffer.
542
543 The number of possible CPUs is used for this computation ignoring
Geert Uytterhoeven5e0d8d52016-06-05 10:47:02 +0200544 hotplugging making the computation optimal for the worst case
545 scenario while allowing a simple algorithm to be used from bootup.
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700546
547 Examples shift values and their meaning:
548 17 => 128 KB for each CPU
549 16 => 64 KB for each CPU
550 15 => 32 KB for each CPU
551 14 => 16 KB for each CPU
552 13 => 8 KB for each CPU
553 12 => 4 KB for each CPU
554
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900555config PRINTK_SAFE_LOG_BUF_SHIFT
556 int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)"
Petr Mladek427934b2016-05-20 17:00:39 -0700557 range 10 21
558 default 13
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900559 depends on PRINTK
Petr Mladek427934b2016-05-20 17:00:39 -0700560 help
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900561 Select the size of an alternate printk per-CPU buffer where messages
562 printed from usafe contexts are temporary stored. One example would
563 be NMI messages, another one - printk recursion. The messages are
564 copied to the main log buffer in a safe context to avoid a deadlock.
565 The value defines the size as a power of 2.
Petr Mladek427934b2016-05-20 17:00:39 -0700566
Sergey Senozhatskyf92bac32016-12-27 23:16:05 +0900567 Those messages are rare and limited. The largest one is when
Petr Mladek427934b2016-05-20 17:00:39 -0700568 a backtrace is printed. It usually fits into 4KB. Select
569 8KB if you want to be on the safe side.
570
571 Examples:
572 17 => 128 KB for each CPU
573 16 => 64 KB for each CPU
574 15 => 32 KB for each CPU
575 14 => 16 KB for each CPU
576 13 => 8 KB for each CPU
577 12 => 4 KB for each CPU
578
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800579#
580# Architectures with an unreliable sched_clock() should select this:
581#
582config HAVE_UNSTABLE_SCHED_CLOCK
583 bool
584
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700585config GENERIC_SCHED_CLOCK
586 bool
587
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200588#
589# For architectures that want to enable the support for NUMA-affine scheduler
590# balancing logic:
591#
592config ARCH_SUPPORTS_NUMA_BALANCING
593 bool
594
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100595#
Mel Gorman72b252a2015-09-04 15:47:32 -0700596# For architectures that prefer to flush all TLBs after a number of pages
597# are unmapped instead of sending one IPI per page to flush. The architecture
598# must provide guarantees on what happens if a clean TLB cache entry is
599# written after the unmap. Details are in mm/rmap.c near the check for
600# should_defer_flush. The architecture should also consider if the full flush
601# and the refill costs are offset by the savings of sending fewer IPIs.
602config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
603 bool
604
605#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100606# For architectures that know their GCC __int128 support is sound
607#
608config ARCH_SUPPORTS_INT128
609 bool
610
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200611# For architectures that (ab)use NUMA to represent different memory regions
612# all cpu-local but of different latencies, such as SuperH.
613#
614config ARCH_WANT_NUMA_VARIABLE_LOCALITY
615 bool
616
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200617config NUMA_BALANCING
618 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200619 depends on ARCH_SUPPORTS_NUMA_BALANCING
620 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
621 depends on SMP && NUMA && MIGRATION
622 help
623 This option adds support for automatic NUMA aware memory/task placement.
624 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400625 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200626
627 This system will be inactive on UMA systems.
628
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800629config NUMA_BALANCING_DEFAULT_ENABLED
630 bool "Automatically enable NUMA aware memory/task placement"
631 default y
632 depends on NUMA_BALANCING
633 help
634 If set, automatic NUMA balancing will be enabled if running on a NUMA
635 machine.
636
Li Zefan23964d22009-01-15 13:50:58 -0800637menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500638 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500639 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700640 help
Li Zefan23964d22009-01-15 13:50:58 -0800641 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800642 use with process control subsystems such as Cpusets, CFS, memory
643 controls or device isolation.
644 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800645 - Documentation/scheduler/sched-design-CFS.txt (CFS)
seokhoon.yoon9991a9c2016-08-02 14:03:13 -0700646 - Documentation/cgroup-v1/ (features for grouping, isolation
Li Zefan45ce80f2009-01-15 13:50:59 -0800647 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700648
649 Say N if unsure.
650
Li Zefan23964d22009-01-15 13:50:58 -0800651if CGROUPS
652
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800653config PAGE_COUNTER
654 bool
655
Andrew Mortonc255a452012-07-31 16:43:02 -0700656config MEMCG
Johannes Weinera0166ec2015-12-17 17:19:56 -0500657 bool "Memory controller"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800658 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500659 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800660 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500661 Provides control over the memory footprint of tasks in a cgroup.
Balbir Singh00f0b822008-03-04 14:28:39 -0800662
Andrew Mortonc255a452012-07-31 16:43:02 -0700663config MEMCG_SWAP
Johannes Weinera0166ec2015-12-17 17:19:56 -0500664 bool "Swap controller"
Andrew Mortonc255a452012-07-31 16:43:02 -0700665 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800666 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500667 Provides control over the swap space consumed by tasks in a cgroup.
668
Andrew Mortonc255a452012-07-31 16:43:02 -0700669config MEMCG_SWAP_ENABLED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500670 bool "Swap controller enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700671 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800672 default y
673 help
674 Memory Resource Controller Swap Extension comes with its price in
675 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700676 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -0700677 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -0800678 parameter should have this option unselected.
679 For those who want to have the feature enabled by default should
680 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700681 then swapaccount=0 does the trick).
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800682
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500683config BLK_CGROUP
684 bool "IO controller"
685 depends on BLOCK
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700686 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500687 ---help---
688 Generic block IO controller cgroup interface. This is the common
689 cgroup interface which should be used by various IO controlling
690 policies.
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700691
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500692 Currently, CFQ IO scheduler uses it to recognize task groups and
693 control disk bandwidth allocation (proportional time slice allocation)
694 to such task groups. It is also used by bio throttling logic in
695 block layer to implement upper limit in IO rates on a device.
Stephane Eraniane5d13672011-02-14 11:20:01 +0200696
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500697 This option only enables generic Block IO controller infrastructure.
698 One needs to also enable actual IO controlling logic/policy. For
699 enabling proportional weight division of disk bandwidth in CFQ, set
700 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
701 CONFIG_BLK_DEV_THROTTLING=y.
702
seokhoon.yoon9991a9c2016-08-02 14:03:13 -0700703 See Documentation/cgroup-v1/blkio-controller.txt for more information.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500704
705config DEBUG_BLK_CGROUP
706 bool "IO controller debugging"
707 depends on BLK_CGROUP
708 default n
709 ---help---
710 Enable some debugging help. Currently it exports additional stat
711 files in a cgroup which can be useful for debugging.
712
713config CGROUP_WRITEBACK
714 bool
715 depends on MEMCG && BLK_CGROUP
716 default y
Stephane Eraniane5d13672011-02-14 11:20:01 +0200717
Dhaval Giani7c941432010-01-20 13:26:18 +0100718menuconfig CGROUP_SCHED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500719 bool "CPU controller"
Dhaval Giani7c941432010-01-20 13:26:18 +0100720 default n
721 help
722 This feature lets CPU scheduler recognize task groups and control CPU
723 bandwidth allocation to such task groups. It uses cgroups to group
724 tasks.
725
726if CGROUP_SCHED
727config FAIR_GROUP_SCHED
728 bool "Group scheduling for SCHED_OTHER"
729 depends on CGROUP_SCHED
730 default CGROUP_SCHED
731
Paul Turnerab84d312011-07-21 09:43:28 -0700732config CFS_BANDWIDTH
733 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -0700734 depends on FAIR_GROUP_SCHED
735 default n
736 help
737 This option allows users to define CPU bandwidth rates (limits) for
738 tasks running within the fair group scheduler. Groups with no limit
739 set are considered to be unconstrained and will run with no
740 restriction.
741 See tip/Documentation/scheduler/sched-bwc.txt for more information.
742
Dhaval Giani7c941432010-01-20 13:26:18 +0100743config RT_GROUP_SCHED
744 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +0100745 depends on CGROUP_SCHED
746 default n
747 help
748 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +0800749 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +0100750 schedule realtime tasks for non-root users until you allocate
751 realtime bandwidth for them.
752 See Documentation/scheduler/sched-rt-group.txt for more information.
753
754endif #CGROUP_SCHED
755
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500756config CGROUP_PIDS
757 bool "PIDs controller"
758 help
759 Provides enforcement of process number limits in the scope of a
760 cgroup. Any attempt to fork more processes than is allowed in the
761 cgroup will fail. PIDs are fundamentally a global resource because it
762 is fairly trivial to reach PID exhaustion before you reach even a
763 conservative kmemcg limit. As a result, it is possible to grind a
764 system to halt without being limited by other cgroup policies. The
Parav Pandit6cc578d2016-03-05 11:30:56 +0530765 PIDs controller is designed to stop this from happening.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500766
767 It should be noted that organisational operations (such as attaching
Parav Pandit6cc578d2016-03-05 11:30:56 +0530768 to a cgroup hierarchy will *not* be blocked by the PIDs controller),
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500769 since the PIDs limit only affects a process's ability to fork, not to
770 attach to a cgroup.
771
Parav Pandit39d3e752017-01-10 00:02:13 +0000772config CGROUP_RDMA
773 bool "RDMA controller"
774 help
775 Provides enforcement of RDMA resources defined by IB stack.
776 It is fairly easy for consumers to exhaust RDMA resources, which
777 can result into resource unavailability to other consumers.
778 RDMA controller is designed to stop this from happening.
779 Attaching processes with active RDMA resources to the cgroup
780 hierarchy is allowed even if can cross the hierarchy's limit.
781
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500782config CGROUP_FREEZER
783 bool "Freezer controller"
784 help
785 Provides a way to freeze and unfreeze all tasks in a
786 cgroup.
787
Johannes Weiner489c2a22016-01-20 15:02:41 -0800788 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
789 controller includes important in-kernel memory consumers per default.
790
791 If you're using cgroup2, say N.
792
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500793config CGROUP_HUGETLB
794 bool "HugeTLB controller"
795 depends on HUGETLB_PAGE
796 select PAGE_COUNTER
Vivek Goyalafc24d42010-04-26 19:27:56 +0200797 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500798 help
799 Provides a cgroup controller for HugeTLB pages.
800 When you enable this, you can put a per cgroup limit on HugeTLB usage.
801 The limit is enforced during page fault. Since HugeTLB doesn't
802 support page reclaim, enforcing the limit at page fault time implies
803 that, the application will get SIGBUS signal if it tries to access
804 HugeTLB pages beyond its limit. This requires the application to know
805 beforehand how much HugeTLB pages it would require for its use. The
806 control group is tracked in the third page lru pointer. This means
807 that we cannot use the controller with huge page less than 3 pages.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200808
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500809config CPUSETS
810 bool "Cpuset controller"
Nicolas Pitree1d4eee2017-06-14 13:19:23 -0400811 depends on SMP
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500812 help
813 This option will let you create and manage CPUSETs which
814 allow dynamically partitioning a system into sets of CPUs and
815 Memory Nodes and assigning tasks to run only within those sets.
816 This is primarily useful on large SMP or NUMA systems.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200817
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500818 Say N if unsure.
Vivek Goyalafc24d42010-04-26 19:27:56 +0200819
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500820config PROC_PID_CPUSET
821 bool "Include legacy /proc/<pid>/cpuset file"
822 depends on CPUSETS
Tejun Heo89e9b9e2015-05-22 17:13:36 -0400823 default y
824
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500825config CGROUP_DEVICE
826 bool "Device controller"
827 help
828 Provides a cgroup controller implementing whitelists for
829 devices which a process in the cgroup can mknod or open.
830
831config CGROUP_CPUACCT
832 bool "Simple CPU accounting controller"
833 help
834 Provides a simple controller for monitoring the
835 total CPU consumed by the tasks in a cgroup.
836
837config CGROUP_PERF
838 bool "Perf controller"
839 depends on PERF_EVENTS
840 help
841 This option extends the perf per-cpu mode to restrict monitoring
842 to threads which belong to the cgroup specified and run on the
843 designated cpu.
844
845 Say N if unsure.
846
Daniel Mack30070982016-11-23 16:52:26 +0100847config CGROUP_BPF
848 bool "Support for eBPF programs attached to cgroups"
Andy Lutomirski483c4932016-12-16 08:33:45 -0800849 depends on BPF_SYSCALL
850 select SOCK_CGROUP_DATA
Daniel Mack30070982016-11-23 16:52:26 +0100851 help
852 Allow attaching eBPF programs to a cgroup using the bpf(2)
853 syscall command BPF_PROG_ATTACH.
854
855 In which context these programs are accessed depends on the type
856 of attachment. For instance, programs that are attached using
857 BPF_CGROUP_INET_INGRESS will be executed on the ingress path of
858 inet sockets.
859
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500860config CGROUP_DEBUG
Waiman Long23b0be42017-06-13 17:18:03 -0400861 bool "Debug controller"
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500862 default n
Waiman Long23b0be42017-06-13 17:18:03 -0400863 depends on DEBUG_KERNEL
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500864 help
865 This option enables a simple controller that exports
Waiman Long23b0be42017-06-13 17:18:03 -0400866 debugging information about the cgroups framework. This
867 controller is for control cgroup debugging only. Its
868 interfaces are not stable.
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500869
870 Say N.
871
Arnd Bergmann73b35142017-01-10 13:08:06 +0100872config SOCK_CGROUP_DATA
873 bool
874 default n
875
Li Zefan23964d22009-01-15 13:50:58 -0800876endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800877
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700878menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -0800879 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -0700880 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -0800881 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -0800882 help
883 Provides the way to make tasks work with different objects using
884 the same id. For example same IPC id may refer to different objects
885 or same user id or pid may refer to different tasks when used in
886 different namespaces.
887
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700888if NAMESPACES
889
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800890config UTS_NS
891 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700892 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -0800893 help
894 In this namespace tasks see different info provided with the
895 uname() system call
896
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800897config IPC_NS
898 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700899 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700900 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800901 help
902 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -0700903 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800904
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800905config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -0700906 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -0800907 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800908 help
909 This allows containers, i.e. vservers, to use user namespaces
910 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -0800911
912 When user namespaces are enabled in the kernel it is
Johannes Weinerd886f4e2016-01-20 15:02:47 -0800913 recommended that the MEMCG option also be enabled and that
914 user-space use the memory control groups to limit the amount
915 of memory a memory unprivileged users can use.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -0800916
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -0800917 If unsure, say N.
918
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800919config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -0700920 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700921 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800922 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +0300923 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +0100924 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -0800925 pid namespaces. This is a building block of containers.
926
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800927config NET_NS
928 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700929 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -0700930 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -0800931 help
932 Allow user space to create what appear to be multiple instances
933 of the network stack.
934
Daniel Lezcano8dd2a822010-10-27 15:34:38 -0700935endif # NAMESPACES
936
Mike Galbraith5091faa2010-11-30 14:18:03 +0100937config SCHED_AUTOGROUP
938 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +0100939 select CGROUPS
940 select CGROUP_SCHED
941 select FAIR_GROUP_SCHED
942 help
943 This option optimizes the scheduler for common desktop workloads by
944 automatically creating and populating task groups. This separation
945 of workloads isolates aggressive CPU burners (like build jobs) from
946 desktop applications. Task group autogeneration is currently based
947 upon task session.
948
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700949config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100950 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700951 depends on SYSFS
952 default n
953 help
954 This option adds code that switches the layout of the "block" class
955 devices, to not show up in /sys/class/block/, but only in
956 /sys/block/.
957
958 This switch is only active when the sysfs.deprecated=1 boot option is
959 passed or the SYSFS_DEPRECATED_V2 option is set.
960
961 This option allows new kernels to run on old distributions and tools,
962 which might get confused by /sys/class/block/. Since 2007/2008 all
963 major distributions and tools handle this just fine.
964
965 Recent distributions and userspace tools after 2009/2010 depend on
966 the existence of /sys/class/block/, and will not work with this
967 option enabled.
968
969 Only if you are using a new kernel on an old distribution, you might
970 need to say Y here.
971
972config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +0100973 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700974 default n
975 depends on SYSFS
976 depends on SYSFS_DEPRECATED
977 help
978 Enable deprecated sysfs by default.
979
980 See the CONFIG_SYSFS_DEPRECATED option for more details about this
981 option.
982
983 Only if you are using a new kernel on an old distribution, you might
984 need to say Y here. Even then, odds are you would not need it
985 enabled, you can always pass the boot option if absolutely necessary.
986
987config RELAY
988 bool "Kernel->user space relay support (formerly relayfs)"
Peter Zijlstra26b56792016-10-11 13:54:33 -0700989 select IRQ_WORK
Daniel Lezcano7af37be2010-10-27 15:34:41 -0700990 help
991 This option enables support for relay interface support in
992 certain file systems (such as debugfs).
993 It is designed to provide an efficient mechanism for tools and
994 facilities to relay large amounts of data from kernel space to
995 user space.
996
997 If unsure, say N.
998
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -0800999config BLK_DEV_INITRD
1000 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1001 depends on BROKEN || !FRV
1002 help
1003 The initial RAM filesystem is a ramfs which is loaded by the
1004 boot loader (loadlin or lilo) and that is mounted as root
1005 before the normal boot procedure. It is typically used to
1006 load modules needed to mount the "real" root file system,
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -02001007 etc. See <file:Documentation/admin-guide/initrd.rst> for details.
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001008
1009 If RAM disk support (BLK_DEV_RAM) is also included, this
1010 also enables initial RAM disk (initrd) support and adds
1011 15 Kbytes (more on some other architectures) to the kernel size.
1012
1013 If unsure say Y.
1014
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001015if BLK_DEV_INITRD
1016
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001017source "usr/Kconfig"
1018
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001019endif
1020
Arnd Bergmann877417e2016-04-25 17:35:27 +02001021choice
1022 prompt "Compiler optimization level"
Ulf Magnusson2cc3ce22017-10-04 01:53:26 +02001023 default CC_OPTIMIZE_FOR_PERFORMANCE
Arnd Bergmann877417e2016-04-25 17:35:27 +02001024
1025config CC_OPTIMIZE_FOR_PERFORMANCE
1026 bool "Optimize for performance"
1027 help
1028 This is the default optimization level for the kernel, building
1029 with the "-O2" compiler flag for best performance and most
1030 helpful compile-time warnings.
1031
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001032config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001033 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001034 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001035 Enabling this option will pass "-Os" instead of "-O2" to
1036 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001037
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001038 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001039
Arnd Bergmann877417e2016-04-25 17:35:27 +02001040endchoice
1041
Randy Dunlap08470622006-09-30 23:28:13 -07001042config SYSCTL
1043 bool
1044
Randy Dunlapb943c462009-03-10 12:55:46 -07001045config ANON_INODES
1046 bool
1047
Mike Frysinger657a5202013-04-30 15:28:45 -07001048config HAVE_UID16
1049 bool
1050
1051config SYSCTL_EXCEPTION_TRACE
1052 bool
1053 help
1054 Enable support for /proc/sys/debug/exception-trace.
1055
1056config SYSCTL_ARCH_UNALIGN_NO_WARN
1057 bool
1058 help
1059 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1060 Allows arch to define/use @no_unaligned_warning to possibly warn
1061 about unaligned access emulation going on under the hood.
1062
1063config SYSCTL_ARCH_UNALIGN_ALLOW
1064 bool
1065 help
1066 Enable support for /proc/sys/kernel/unaligned-trap
1067 Allows arches to define/use @unaligned_enabled to runtime toggle
1068 the unaligned access emulation.
1069 see arch/parisc/kernel/unaligned.c for reference
1070
Mike Frysinger657a5202013-04-30 15:28:45 -07001071config HAVE_PCSPKR_PLATFORM
1072 bool
1073
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001074# interpreter that classic socket filters depend on
1075config BPF
1076 bool
1077
David Rientjes6a108a12011-01-20 14:44:16 -08001078menuconfig EXPERT
1079 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001080 # Unhide debug options, to make the on-by-default options visible
1081 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 help
1083 This option allows certain base kernel options and settings
1084 to be disabled or tweaked. This is for specialized
1085 environments which can tolerate a "non-standard" kernel.
1086 Only use this if you really know what you are doing.
1087
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001088config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001089 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001090 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001091 default y
1092 help
1093 This enables the legacy 16-bit UID syscall wrappers.
1094
Iulia Manda28138932015-04-15 16:16:41 -07001095config MULTIUSER
1096 bool "Multiple users, groups and capabilities support" if EXPERT
1097 default y
1098 help
1099 This option enables support for non-root users, groups and
1100 capabilities.
1101
1102 If you say N here, all processes will run with UID 0, GID 0, and all
1103 possible capabilities. Saying N here also compiles out support for
1104 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1105 setgid, and capset.
1106
1107 If unsure, say Y here.
1108
Fabian Frederickf6187762014-06-04 16:11:12 -07001109config SGETMASK_SYSCALL
1110 bool "sgetmask/ssetmask syscalls support" if EXPERT
1111 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1112 ---help---
1113 sys_sgetmask and sys_ssetmask are obsolete system calls
1114 no longer supported in libc but still enabled by default in some
1115 architectures.
1116
1117 If unsure, leave the default option here.
1118
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001119config SYSFS_SYSCALL
1120 bool "Sysfs syscall support" if EXPERT
1121 default y
1122 ---help---
1123 sys_sysfs is an obsolete system call no longer supported in libc.
1124 Note that disabling this option is more secure but might break
1125 compatibility with some systems.
1126
1127 If unsure say Y here.
1128
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001129config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001130 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001131 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001132 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001133 select SYSCTL
1134 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001135 sys_sysctl uses binary paths that have been found challenging
1136 to properly maintain and use. The interface in /proc/sys
1137 using paths with ascii names is now the primary path to this
1138 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001139
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001140 Almost nothing using the binary sysctl interface so if you are
1141 trying to save some space it is probably safe to disable this,
1142 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001143
WANG Congc736de62011-11-02 13:39:25 -07001144 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001145
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001146config FHANDLE
1147 bool "open by fhandle syscalls" if EXPERT
1148 select EXPORTFS
1149 default y
1150 help
1151 If you say Y here, a user level program will be able to map
1152 file names to handle and then later use the handle for
1153 different file system operations. This is useful in implementing
1154 userspace file servers, which now track files using handles instead
1155 of names. The handle would remain the same even if file names
1156 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
1157 syscalls.
1158
Nicolas Pitrebaa73d92016-11-11 00:10:10 -05001159config POSIX_TIMERS
1160 bool "Posix Clocks & timers" if EXPERT
1161 default y
1162 help
1163 This includes native support for POSIX timers to the kernel.
1164 Some embedded systems have no use for them and therefore they
1165 can be configured out to reduce the size of the kernel image.
1166
1167 When this option is disabled, the following syscalls won't be
1168 available: timer_create, timer_gettime: timer_getoverrun,
1169 timer_settime, timer_delete, clock_adjtime, getitimer,
1170 setitimer, alarm. Furthermore, the clock_settime, clock_gettime,
1171 clock_getres and clock_nanosleep syscalls will be limited to
1172 CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only.
1173
1174 If unsure say y.
1175
Matt Mackalld59745c2005-05-01 08:59:02 -07001176config PRINTK
1177 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001178 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001179 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001180 help
1181 This option enables normal printk support. Removing it
1182 eliminates most of the message strings from the kernel image
1183 and makes the kernel more or less silent. As this makes it
1184 very difficult to diagnose system problems, saying N here is
1185 strongly discouraged.
1186
Petr Mladek42a0bb32016-05-20 17:00:33 -07001187config PRINTK_NMI
1188 def_bool y
1189 depends on PRINTK
1190 depends on HAVE_NMI
1191
Matt Mackallc8538a72005-05-01 08:59:01 -07001192config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001193 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001194 default y
1195 help
1196 Disabling this option eliminates support for BUG and WARN, reducing
1197 the size of your kernel image and potentially quietly ignoring
1198 numerous fatal conditions. You should only consider disabling this
1199 option for embedded systems with no facilities for reporting errors.
1200 Just say Y.
1201
Matt Mackall708e9a72006-01-08 01:05:25 -08001202config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001203 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001204 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001205 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001206 help
1207 Enable support for generating core dumps. Disabling saves about 4k.
1208
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001209
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001210config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001211 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001212 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001213 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001214 default y
1215 help
1216 This option allows to disable the internal PC-Speaker
1217 support, saving some memory.
1218
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219config BASE_FULL
1220 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001221 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 help
1223 Disabling this option reduces the size of miscellaneous core
1224 kernel data structures. This saves memory on small machines,
1225 but may reduce performance.
1226
1227config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001228 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 default y
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001230 imply RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 help
1232 Disabling this option will cause the kernel to be built without
1233 support for "fast userspace mutexes". The resulting kernel may not
1234 run glibc-based applications correctly.
1235
Nicolas Pitrebc2eecd2017-08-01 00:31:32 -04001236config FUTEX_PI
1237 bool
1238 depends on FUTEX && RT_MUTEXES
1239 default y
1240
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001241config HAVE_FUTEX_CMPXCHG
1242 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001243 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001244 help
1245 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1246 is implemented and always working. This removes a couple of runtime
1247 checks.
1248
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001250 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001252 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 help
1254 Disabling this option will cause the kernel to be built without
1255 support for epoll family of system calls.
1256
Davide Libenzifba2afa2007-05-10 22:23:13 -07001257config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001258 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001259 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001260 default y
1261 help
1262 Enable the signalfd() system call that allows to receive signals
1263 on a file descriptor.
1264
1265 If unsure, say Y.
1266
Davide Libenzib215e282007-05-10 22:23:16 -07001267config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001268 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001269 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001270 default y
1271 help
1272 Enable the timerfd() system call that allows to receive timer
1273 events on a file descriptor.
1274
1275 If unsure, say Y.
1276
Davide Libenzie1ad7462007-05-10 22:23:19 -07001277config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001278 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001279 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001280 default y
1281 help
1282 Enable the eventfd() system call that allows to receive both
1283 kernel notification (ie. KAIO) or userspace notifications.
1284
1285 If unsure, say Y.
1286
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001288 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 default y
1290 depends on MMU
1291 help
1292 The shmem is an internal filesystem used to manage shared memory.
1293 It is backed by swap and manages resource limits. It is also exported
1294 to userspace as tmpfs if TMPFS is enabled. Disabling this
1295 option replaces shmem and tmpfs with the much simpler ramfs code,
1296 which may be appropriate on small systems without swap.
1297
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001298config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001299 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001300 default y
1301 help
1302 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001303 by some high performance threaded applications. Disabling
1304 this option saves about 7k.
1305
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001306config ADVISE_SYSCALLS
1307 bool "Enable madvise/fadvise syscalls" if EXPERT
1308 default y
1309 help
1310 This option enables the madvise and fadvise syscalls, used by
1311 applications to advise the kernel about their future memory or file
1312 usage, improving performance. If building an embedded system where no
1313 applications use these syscalls, you can disable this option to save
1314 space.
1315
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001316config MEMBARRIER
1317 bool "Enable membarrier() system call" if EXPERT
1318 default y
1319 help
1320 Enable the membarrier() system call that allows issuing memory
1321 barriers across all running threads, which can be used to distribute
1322 the cost of user-space memory barriers asymmetrically by transforming
1323 pairs of memory barriers into pairs consisting of membarrier() and a
1324 compiler barrier.
1325
1326 If unsure, say Y.
1327
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001328config CHECKPOINT_RESTORE
1329 bool "Checkpoint/restore support" if EXPERT
1330 select PROC_CHILDREN
1331 default n
1332 help
1333 Enables additional kernel features in a sake of checkpoint/restore.
1334 In particular it adds auxiliary prctl codes to setup process text,
1335 data and heap segment sizes, and a few additional /proc filesystem
1336 entries.
1337
1338 If unsure, say N here.
1339
1340config KALLSYMS
1341 bool "Load all symbols for debugging/ksymoops" if EXPERT
1342 default y
1343 help
1344 Say Y here to let the kernel print out symbolic crash information and
1345 symbolic stack backtraces. This increases the size of the kernel
1346 somewhat, as all symbols have to be loaded into the kernel image.
1347
1348config KALLSYMS_ALL
1349 bool "Include all symbols in kallsyms"
1350 depends on DEBUG_KERNEL && KALLSYMS
1351 help
1352 Normally kallsyms only contains the symbols of functions for nicer
1353 OOPS messages and backtraces (i.e., symbols from the text and inittext
1354 sections). This is sufficient for most cases. And only in very rare
1355 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1356 names of variables from the data sections, etc).
1357
1358 This option makes sure that all symbols are loaded into the kernel
1359 image (i.e., symbols from all sections) in cost of increased kernel
1360 size (depending on the kernel configuration, it may be 300KiB or
1361 something like this).
1362
1363 Say N unless you really need all symbols.
1364
1365config KALLSYMS_ABSOLUTE_PERCPU
1366 bool
1367 depends on KALLSYMS
1368 default X86_64 && SMP
1369
1370config KALLSYMS_BASE_RELATIVE
1371 bool
1372 depends on KALLSYMS
1373 default !IA64 && !(TILE && 64BIT)
1374 help
1375 Instead of emitting them as absolute values in the native word size,
1376 emit the symbol references in the kallsyms table as 32-bit entries,
1377 each containing a relative value in the range [base, base + U32_MAX]
1378 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1379 an absolute value in the range [0, S32_MAX] or a relative value in the
1380 range [base, base + S32_MAX], where base is the lowest relative symbol
1381 address encountered in the image.
1382
1383 On 64-bit builds, this reduces the size of the address table by 50%,
1384 but more importantly, it results in entries whose values are build
1385 time constants, and no relocation pass is required at runtime to fix
1386 up the entries based on the runtime load address of the kernel.
1387
1388# end of the "standard kernel features (expert users)" menu
1389
1390# syscall, maps, verifier
1391config BPF_SYSCALL
1392 bool "Enable bpf() system call"
1393 select ANON_INODES
1394 select BPF
1395 default n
1396 help
1397 Enable the bpf() system call that allows to manipulate eBPF
1398 programs and maps via file descriptors.
1399
Alexei Starovoitov290af862018-01-09 10:04:29 -08001400config BPF_JIT_ALWAYS_ON
1401 bool "Permanently enable BPF JIT and remove BPF interpreter"
1402 depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
1403 help
1404 Enables BPF JIT and removes BPF interpreter to avoid
1405 speculative execution of BPF instructions by the interpreter
1406
Randy Dunlapd1b069f2017-11-17 15:31:47 -08001407config USERFAULTFD
1408 bool "Enable userfaultfd() system call"
1409 select ANON_INODES
1410 depends on MMU
1411 help
1412 Enable the userfaultfd() system call that allows to intercept and
1413 handle page faults in userland.
1414
Mathieu Desnoyers3ccfebe2018-01-29 15:20:11 -05001415config ARCH_HAS_MEMBARRIER_CALLBACKS
1416 bool
1417
Mathieu Desnoyers70216e12018-01-29 15:20:17 -05001418config ARCH_HAS_MEMBARRIER_SYNC_CORE
1419 bool
1420
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001421config EMBEDDED
1422 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001423 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001424 select EXPERT
1425 help
1426 This option should be enabled if compiling the kernel for
1427 an embedded system so certain expert options are available
1428 for configuration.
1429
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001430config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001431 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001432 help
1433 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001434
Peter Zijlstra906010b2009-09-21 16:08:49 +02001435config PERF_USE_VMALLOC
1436 bool
1437 help
1438 See tools/perf/design.txt for details
1439
William Breathitt Grayad90a3d2017-01-10 13:50:54 -05001440config PC104
1441 bool "PC/104 support"
1442 help
1443 Expose PC/104 form factor device drivers and options available for
1444 selection and configuration. Enable this option if your target
1445 machine has a PC/104 bus.
1446
Ingo Molnar57c0c152009-09-21 12:20:38 +02001447menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001448
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001449config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001450 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001451 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001452 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001453 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001454 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001455 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001456 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001457 Enable kernel support for various performance events provided
1458 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001459
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001460 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001461 use of generic tracepoints.
1462
1463 Most modern CPUs support performance events via performance
1464 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001465 types of hw events: such as instructions executed, cachemisses
1466 suffered, or branches mis-predicted - without slowing down the
1467 kernel or applications. These registers can also trigger interrupts
1468 when a threshold number of events have passed - and can thus be
1469 used to profile the code that runs on that CPU.
1470
Ingo Molnar57c0c152009-09-21 12:20:38 +02001471 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001472 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001473 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001474 provides per task and per CPU counters, and it provides event
1475 capabilities on top of those.
1476
1477 Say Y if unsure.
1478
Peter Zijlstra906010b2009-09-21 16:08:49 +02001479config DEBUG_PERF_USE_VMALLOC
1480 default n
1481 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001482 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001483 select PERF_USE_VMALLOC
1484 help
1485 Use vmalloc memory to back perf mmap() buffers.
1486
1487 Mostly useful for debugging the vmalloc code on platforms
1488 that don't require it.
1489
1490 Say N if unsure.
1491
Thomas Gleixner0793a612008-12-04 20:12:29 +01001492endmenu
1493
Christoph Lameterf8891e52006-06-30 01:55:45 -07001494config VM_EVENT_COUNTERS
1495 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001496 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001497 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001498 VM event counters are needed for event counts to be shown.
1499 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001500 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001501 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001502
Christoph Lameter41ecc552007-05-09 02:32:44 -07001503config SLUB_DEBUG
1504 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001505 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001506 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001507 help
1508 SLUB has extensive debug support features. Disabling these can
1509 result in significant savings in code size. This also disables
1510 SLUB sysfs support. /sys/slab will not exist and there will be
1511 no support for cache validation etc.
1512
Tejun Heo1663f262017-02-22 15:41:39 -08001513config SLUB_MEMCG_SYSFS_ON
1514 default n
1515 bool "Enable memcg SLUB sysfs support by default" if EXPERT
1516 depends on SLUB && SYSFS && MEMCG
1517 help
1518 SLUB creates a directory under /sys/kernel/slab for each
1519 allocation cache to host info and debug files. If memory
1520 cgroup is enabled, each cache can have per memory cgroup
1521 caches. SLUB can create the same sysfs directories for these
1522 caches under /sys/kernel/slab/CACHE/cgroup but it can lead
1523 to a very high number of debug files being created. This is
1524 controlled by slub_memcg_sysfs boot parameter and this
1525 config option determines the parameter's default value.
1526
Randy Dunlapb943c462009-03-10 12:55:46 -07001527config COMPAT_BRK
1528 bool "Disable heap randomization"
1529 default y
1530 help
1531 Randomizing heap placement makes heap exploits harder, but it
1532 also breaks ancient binaries (including anything libc5 based).
1533 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001534 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001535 /proc/sys/kernel/randomize_va_space to 2.
1536
1537 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1538
Christoph Lameter81819f02007-05-06 14:49:36 -07001539choice
1540 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001541 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001542 help
1543 This option allows to select a slab allocator.
1544
1545config SLAB
1546 bool "SLAB"
Kees Cook04385fc2016-06-23 15:20:59 -07001547 select HAVE_HARDENED_USERCOPY_ALLOCATOR
Christoph Lameter81819f02007-05-06 14:49:36 -07001548 help
1549 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001550 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001551 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001552
1553config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001554 bool "SLUB (Unqueued Allocator)"
Kees Cooked18adc2016-06-23 15:24:05 -07001555 select HAVE_HARDENED_USERCOPY_ALLOCATOR
Christoph Lameter81819f02007-05-06 14:49:36 -07001556 help
1557 SLUB is a slab allocator that minimizes cache line usage
1558 instead of managing queues of cached objects (SLAB approach).
1559 Per cpu caching is realized using slabs of objects instead
1560 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001561 and has enhanced diagnostics. SLUB is the default choice for
1562 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001563
1564config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001565 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001566 bool "SLOB (Simple Allocator)"
1567 help
Matt Mackall37291452008-02-04 22:29:38 -08001568 SLOB replaces the stock allocator with a drastically simpler
1569 allocator. SLOB is generally more space efficient but
1570 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001571
1572endchoice
1573
Kees Cook7660a6f2017-07-06 15:36:40 -07001574config SLAB_MERGE_DEFAULT
1575 bool "Allow slab caches to be merged"
1576 default y
1577 help
1578 For reduced kernel memory fragmentation, slab caches can be
1579 merged when they share the same size and other characteristics.
1580 This carries a risk of kernel heap overflows being able to
1581 overwrite objects from merged caches (and more easily control
1582 cache layout), which makes such heap attacks easier to exploit
1583 by attackers. By keeping caches unmerged, these kinds of exploits
1584 can usually only damage objects in the same cache. To disable
1585 merging at runtime, "slab_nomerge" can be passed on the kernel
1586 command line.
1587
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001588config SLAB_FREELIST_RANDOM
1589 default n
Thomas Garnier210e7a42016-07-26 15:21:59 -07001590 depends on SLAB || SLUB
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001591 bool "SLAB freelist randomization"
1592 help
Thomas Garnier210e7a42016-07-26 15:21:59 -07001593 Randomizes the freelist order used on creating new pages. This
Thomas Garnierc7ce4f602016-05-19 17:10:37 -07001594 security feature reduces the predictability of the kernel slab
1595 allocator against heap overflows.
1596
Kees Cook2482dde2017-09-06 16:19:18 -07001597config SLAB_FREELIST_HARDENED
1598 bool "Harden slab freelist metadata"
1599 depends on SLUB
1600 help
1601 Many kernel heap attacks try to target slab cache metadata and
1602 other infrastructure. This options makes minor performance
1603 sacrifies to harden the kernel slab allocator against common
1604 freelist exploit methods.
1605
Joonsoo Kim345c9052013-06-19 14:05:52 +09001606config SLUB_CPU_PARTIAL
1607 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001608 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001609 bool "SLUB per cpu partial cache"
1610 help
1611 Per cpu partial caches accellerate objects allocation and freeing
1612 that is local to a processor at the price of more indeterminism
1613 in the latency of the free. On overflow these caches will be cleared
1614 which requires the taking of locks that may cause latency spikes.
1615 Typically one would choose no for a realtime system.
1616
Jie Zhangea637632009-12-14 18:00:02 -08001617config MMAP_ALLOW_UNINITIALIZED
1618 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001619 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001620 default n
1621 help
1622 Normally, and according to the Linux spec, anonymous memory obtained
1623 from mmap() has it's contents cleared before it is passed to
1624 userspace. Enabling this config option allows you to request that
1625 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1626 providing a huge performance boost. If this option is not enabled,
1627 then the flag will be ignored.
1628
1629 This is taken advantage of by uClibc's malloc(), and also by
1630 ELF-FDPIC binfmt's brk and stack allocator.
1631
1632 Because of the obvious security issues, this option should only be
1633 enabled on embedded devices where you control what is run in
1634 userspace. Since that isn't generally a problem on no-MMU systems,
1635 it is normally safe to say Y here.
1636
1637 See Documentation/nommu-mmap.txt for more information.
1638
David Howells091f6e22015-07-20 21:16:28 +01001639config SYSTEM_DATA_VERIFICATION
1640 def_bool n
1641 select SYSTEM_TRUSTED_KEYRING
1642 select KEYS
1643 select CRYPTO
David Howellsd43de6c2016-03-03 21:49:27 +00001644 select CRYPTO_RSA
David Howells091f6e22015-07-20 21:16:28 +01001645 select ASYMMETRIC_KEY_TYPE
1646 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
David Howells091f6e22015-07-20 21:16:28 +01001647 select ASN1
1648 select OID_REGISTRY
1649 select X509_CERTIFICATE_PARSER
1650 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001651 help
David Howells091f6e22015-07-20 21:16:28 +01001652 Provide PKCS#7 message verification using the contents of the system
1653 trusted keyring to provide public keys. This then can be used for
1654 module verification, kexec image verification and firmware blob
1655 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001656
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001657config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001658 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001659 help
1660 Say Y here to enable the extended profiling support mechanisms used
1661 by profilers such as OProfile.
1662
Ingo Molnar5f87f112008-07-23 14:15:22 +02001663#
1664# Place an empty function call at each tracepoint site. Can be
1665# dynamically changed for a probe function.
1666#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001667config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001668 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001669
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001670source "arch/Kconfig"
1671
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672endmenu # General setup
1673
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001674config HAVE_GENERIC_DMA_COHERENT
1675 bool
1676 default n
1677
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001678config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001679 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001680
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681config BASE_SMALL
1682 int
1683 default 0 if BASE_FULL
1684 default 1 if !BASE_FULL
1685
Jan Engelhardt66da5732007-07-15 23:39:29 -07001686menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001688 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 help
1690 Kernel modules are small pieces of compiled code which can
1691 be inserted in the running kernel, rather than being
1692 permanently built into the kernel. You use the "modprobe"
1693 tool to add (and sometimes remove) them. If you say Y here,
1694 many parts of the kernel can be built as modules (by
1695 answering M instead of Y where indicated): this is most
1696 useful for infrequently used options which are not required
1697 for booting. For more information, see the man pages for
1698 modprobe, lsmod, modinfo, insmod and rmmod.
1699
1700 If you say Y here, you will need to run "make
1701 modules_install" to put the modules under /lib/modules/
1702 where modprobe can find them (you may need to be root to do
1703 this).
1704
1705 If unsure, say Y.
1706
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001707if MODULES
1708
Linus Torvalds826e4502008-05-04 17:04:16 -07001709config MODULE_FORCE_LOAD
1710 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001711 default n
1712 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001713 Allow loading of modules without version information (ie. modprobe
1714 --force). Forced module loading sets the 'F' (forced) taint flag and
1715 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001716
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717config MODULE_UNLOAD
1718 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 help
1720 Without this option you will not be able to unload any
1721 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001722 anyway), which makes your kernel smaller, faster
1723 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724
1725config MODULE_FORCE_UNLOAD
1726 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001727 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 help
1729 This option allows you to force a module to unload, even if the
1730 kernel believes it is unsafe: the kernel will remove the module
1731 without waiting for anyone to stop using it (using the -f option to
1732 rmmod). This is mainly for kernel developers and desperate users.
1733 If unsure, say N.
1734
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001736 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 help
1738 Usually, you have to use modules compiled with your kernel.
1739 Saying Y here makes it sometimes possible to use modules
1740 compiled for different kernels, by adding enough information
1741 to the modules to (hopefully) spot any changes which would
1742 make them incompatible with the kernel you are running. If
1743 unsure, say N.
1744
Ard Biesheuvel56067812017-02-03 09:54:05 +00001745config MODULE_REL_CRCS
1746 bool
1747 depends on MODVERSIONS
1748
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749config MODULE_SRCVERSION_ALL
1750 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 help
1752 Modules which contain a MODULE_VERSION get an extra "srcversion"
1753 field inserted into their modinfo section, which contains a
1754 sum of the source files which made it. This helps maintainers
1755 see exactly which source was used to build a module (since
1756 others sometimes change the module source without updating
1757 the version). With this option, such a "srcversion" field
1758 will be created for all modules. If unsure, say N.
1759
Rusty Russell106a4ee2012-09-26 10:09:40 +01001760config MODULE_SIG
1761 bool "Module signature verification"
1762 depends on MODULES
David Howells091f6e22015-07-20 21:16:28 +01001763 select SYSTEM_DATA_VERIFICATION
Rusty Russell106a4ee2012-09-26 10:09:40 +01001764 help
1765 Check modules for valid signatures upon load: the signature
1766 is simply appended to the module. For more information see
Nathan Chancellorcbdc8212017-09-10 02:48:29 -07001767 <file:Documentation/admin-guide/module-signing.rst>.
Rusty Russell106a4ee2012-09-26 10:09:40 +01001768
David Howells228c37f2015-08-11 12:38:54 +01001769 Note that this option adds the OpenSSL development packages as a
1770 kernel build dependency so that the signing tool can use its crypto
1771 library.
1772
David Howellsea0b6dc2012-09-26 10:09:50 +01001773 !!!WARNING!!! If you enable this option, you MUST make sure that the
1774 module DOES NOT get stripped after being signed. This includes the
1775 debuginfo strip done by some packagers (such as rpmbuild) and
1776 inclusion into an initramfs that wants the module size reduced.
1777
Rusty Russell106a4ee2012-09-26 10:09:40 +01001778config MODULE_SIG_FORCE
1779 bool "Require modules to be validly signed"
1780 depends on MODULE_SIG
1781 help
1782 Reject unsigned modules or signed modules for which we don't have a
1783 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001784
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301785config MODULE_SIG_ALL
1786 bool "Automatically sign all modules"
1787 default y
1788 depends on MODULE_SIG
1789 help
1790 Sign all modules during make modules_install. Without this option,
1791 modules must be signed manually, using the scripts/sign-file tool.
1792
1793comment "Do not forget to sign required modules with scripts/sign-file"
1794 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1795
David Howellsea0b6dc2012-09-26 10:09:50 +01001796choice
1797 prompt "Which hash algorithm should modules be signed with?"
1798 depends on MODULE_SIG
1799 help
1800 This determines which sort of hashing algorithm will be used during
1801 signature generation. This algorithm _must_ be built into the kernel
1802 directly so that signature verification can take place. It is not
1803 possible to load a signed module containing the algorithm to check
1804 the signature on that module.
1805
1806config MODULE_SIG_SHA1
1807 bool "Sign modules with SHA-1"
1808 select CRYPTO_SHA1
1809
1810config MODULE_SIG_SHA224
1811 bool "Sign modules with SHA-224"
1812 select CRYPTO_SHA256
1813
1814config MODULE_SIG_SHA256
1815 bool "Sign modules with SHA-256"
1816 select CRYPTO_SHA256
1817
1818config MODULE_SIG_SHA384
1819 bool "Sign modules with SHA-384"
1820 select CRYPTO_SHA512
1821
1822config MODULE_SIG_SHA512
1823 bool "Sign modules with SHA-512"
1824 select CRYPTO_SHA512
1825
1826endchoice
1827
Michal Marek22753672013-01-25 13:41:00 +10301828config MODULE_SIG_HASH
1829 string
1830 depends on MODULE_SIG
1831 default "sha1" if MODULE_SIG_SHA1
1832 default "sha224" if MODULE_SIG_SHA224
1833 default "sha256" if MODULE_SIG_SHA256
1834 default "sha384" if MODULE_SIG_SHA384
1835 default "sha512" if MODULE_SIG_SHA512
1836
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301837config MODULE_COMPRESS
1838 bool "Compress modules on installation"
1839 depends on MODULES
1840 help
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301841
Rusty Russellb6c09b52015-06-16 12:16:22 +09301842 Compresses kernel modules when 'make modules_install' is run; gzip or
1843 xz depending on "Compression algorithm" below.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301844
Rusty Russellb6c09b52015-06-16 12:16:22 +09301845 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301846
Rusty Russellb6c09b52015-06-16 12:16:22 +09301847 Out-of-tree kernel modules installed using Kbuild will also be
1848 compressed upon installation.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301849
Rusty Russellb6c09b52015-06-16 12:16:22 +09301850 Note: for modules inside an initrd or initramfs, it's more efficient
1851 to compress the whole initrd or initramfs instead.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301852
Rusty Russellb6c09b52015-06-16 12:16:22 +09301853 Note: This is fully compatible with signed modules.
1854
1855 If in doubt, say N.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301856
1857choice
1858 prompt "Compression algorithm"
1859 depends on MODULE_COMPRESS
1860 default MODULE_COMPRESS_GZIP
1861 help
1862 This determines which sort of compression will be used during
1863 'make modules_install'.
1864
1865 GZIP (default) and XZ are supported.
1866
1867config MODULE_COMPRESS_GZIP
1868 bool "GZIP"
1869
1870config MODULE_COMPRESS_XZ
1871 bool "XZ"
1872
1873endchoice
1874
Nicolas Pitredbacb0e2016-01-26 21:51:05 -05001875config TRIM_UNUSED_KSYMS
1876 bool "Trim unused exported kernel symbols"
1877 depends on MODULES && !UNUSED_SYMBOLS
1878 help
1879 The kernel and some modules make many symbols available for
1880 other modules to use via EXPORT_SYMBOL() and variants. Depending
1881 on the set of modules being selected in your kernel configuration,
1882 many of those exported symbols might never be used.
1883
1884 This option allows for unused exported symbols to be dropped from
1885 the build. In turn, this provides the compiler more opportunities
1886 (especially when using LTO) for optimizing the code and reducing
1887 binary size. This might have some security advantages as well.
1888
Valdis Kletnieksf1cb6372016-08-02 14:07:27 -07001889 If unsure, or if you need to build out-of-tree modules, say N.
Nicolas Pitredbacb0e2016-01-26 21:51:05 -05001890
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001891endif # MODULES
1892
Peter Zijlstra6c9692e2015-05-27 11:09:37 +09301893config MODULES_TREE_LOOKUP
1894 def_bool y
1895 depends on PERF_EVENTS || TRACING
1896
Rusty Russell98a79d62008-12-13 21:19:41 +10301897config INIT_ALL_POSSIBLE
1898 bool
1899 help
Rusty Russell5f054e32012-03-29 15:38:31 +10301900 Back when each arch used to define their own cpu_online_mask and
1901 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10301902 with all 1s, and others with all 0s. When they were centralised,
1903 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01001904 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10301905
Jens Axboe3a65dfe2005-11-04 08:43:35 +01001906source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07001907
1908config PREEMPT_NOTIFIERS
1909 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01001910
Steffen Klassert16295be2010-01-06 19:47:10 +11001911config PADATA
1912 depends on SMP
1913 bool
1914
David Howells4520c6a2012-09-21 23:31:13 +01001915config ASN1
1916 tristate
1917 help
1918 Build a simple ASN.1 grammar compiler that produces a bytecode output
1919 that can be interpreted by the ASN.1 stream decoder and used to
1920 inform it as to what tags are to be expected in a stream and what
1921 functions to call on what tags.
1922
Thomas Gleixner6beb0002009-11-09 15:21:34 +00001923source "kernel/Kconfig.locks"
Mathieu Desnoyerse61938a2018-01-29 15:20:15 -05001924
1925config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
1926 bool