blob: fd664b3ab99ef79432643ab3e954943e759f81ca [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
Al Boldiff0cfc62007-07-31 00:39:23 -070029menu "General setup"
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031config BROKEN
32 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34config BROKEN_ON_SMP
35 bool
36 depends on BROKEN || !SMP
37 default y
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config INIT_ENV_ARG_LIMIT
40 int
Adrian Bunkdd673bc2006-06-30 01:55:51 -070041 default 32 if !UML
42 default 128 if UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 help
Randy Dunlap34ad92c2005-10-30 15:01:46 -080044 Maximum of each of the number of arguments and environment
45 variables passed to init from the kernel command line.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Roland McGrath84336462009-12-21 16:24:06 -080048config CROSS_COMPILE
49 string "Cross-compiler tool prefix"
50 help
51 Same as running 'make CROSS_COMPILE=prefix-' but stored for
52 default make runs in this kernel build directory. You don't
53 need to set this unless you want the configured kernel build
54 directory to select the cross-compiler automatically.
55
Jiri Slaby4bb16672013-05-22 10:56:24 +020056config COMPILE_TEST
57 bool "Compile also drivers which will not load"
58 default n
59 help
60 Some drivers can be compiled on a different platform than they are
61 intended to be run on. Despite they cannot be loaded there (or even
62 when they load they cannot be used due to missing HW support),
63 developers still, opposing to distributors, might want to build such
64 drivers to compile-test them.
65
66 If you are a developer and want to build everything available, say Y
67 here. If you are a user/distributor, say N here to exclude useless
68 drivers to be distributed.
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070config LOCALVERSION
71 string "Local version - append to kernel release"
72 help
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
79
Ryan Andersonaaebf432005-07-31 04:57:49 -040080config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
82 default y
83 help
84 This will try to automatically determine if the current tree is a
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020085 release tree by looking for git tags that belong to the current
86 top of tree revision.
Ryan Andersonaaebf432005-07-31 04:57:49 -040087
88 A string of the format -gxxxxxxxx will be added to the localversion
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020089 if a git-based tree is found. The string generated by this will be
Ryan Andersonaaebf432005-07-31 04:57:49 -040090 appended after any matching localversion* files, and after the value
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020091 set in CONFIG_LOCALVERSION.
Ryan Andersonaaebf432005-07-31 04:57:49 -040092
Robert P. J. Day6e5a5422007-05-01 23:08:11 +020093 (The actual string used here is the first eight characters produced
94 by running the command:
95
96 $ git rev-parse --verify HEAD
97
98 which is done within the script "scripts/setlocalversion".)
Ryan Andersonaaebf432005-07-31 04:57:49 -040099
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800100config HAVE_KERNEL_GZIP
101 bool
102
103config HAVE_KERNEL_BZIP2
104 bool
105
106config HAVE_KERNEL_LZMA
107 bool
108
Lasse Collin3ebe1242011-01-12 17:01:23 -0800109config HAVE_KERNEL_XZ
110 bool
111
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800112config HAVE_KERNEL_LZO
113 bool
114
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700115config HAVE_KERNEL_LZ4
116 bool
117
Alain Knaff30d65db2009-01-04 22:46:17 +0100118choice
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800119 prompt "Kernel compression mode"
120 default KERNEL_GZIP
H. Peter Anvin2d3c6272013-11-14 21:43:47 -0800121 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 -0800122 help
Alain Knaff30d65db2009-01-04 22:46:17 +0100123 The linux kernel is a kind of self-extracting executable.
124 Several compression algorithms are available, which differ
125 in efficiency, compression and decompression speed.
126 Compression speed is only relevant when building a kernel.
127 Decompression speed is relevant at each boot.
128
129 If you have any problems with bzip2 or lzma compressed
130 kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
131 version of this functionality (bzip2 only), for 2.4, was
132 supplied by Christian Ludwig)
133
134 High compression options are mostly useful for users, who
135 are low on disk space (embedded systems), but for whom ram
136 size matters less.
137
138 If in doubt, select 'gzip'
139
140config KERNEL_GZIP
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800141 bool "Gzip"
142 depends on HAVE_KERNEL_GZIP
143 help
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800144 The old and tried gzip compression. It provides a good balance
145 between compression ratio and decompression speed.
Alain Knaff30d65db2009-01-04 22:46:17 +0100146
147config KERNEL_BZIP2
148 bool "Bzip2"
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800149 depends on HAVE_KERNEL_BZIP2
Alain Knaff30d65db2009-01-04 22:46:17 +0100150 help
151 Its compression ratio and speed is intermediate.
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700152 Decompression speed is slowest among the choices. The kernel
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800153 size is about 10% smaller with bzip2, in comparison to gzip.
154 Bzip2 uses a large amount of memory. For modern kernels you
155 will need at least 8MB RAM or more for booting.
Alain Knaff30d65db2009-01-04 22:46:17 +0100156
157config KERNEL_LZMA
H. Peter Anvin2e9f3bd2009-01-04 15:41:25 -0800158 bool "LZMA"
159 depends on HAVE_KERNEL_LZMA
160 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700161 This compression algorithm's ratio is best. Decompression speed
162 is between gzip and bzip2. Compression is slowest.
163 The kernel size is about 33% smaller with LZMA in comparison to gzip.
Alain Knaff30d65db2009-01-04 22:46:17 +0100164
Lasse Collin3ebe1242011-01-12 17:01:23 -0800165config KERNEL_XZ
166 bool "XZ"
167 depends on HAVE_KERNEL_XZ
168 help
169 XZ uses the LZMA2 algorithm and instruction set specific
170 BCJ filters which can improve compression ratio of executable
171 code. The size of the kernel is about 30% smaller with XZ in
172 comparison to gzip. On architectures for which there is a BCJ
173 filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ
174 will create a few percent smaller kernel than plain LZMA.
175
176 The speed is about the same as with LZMA: The decompression
177 speed of XZ is better than that of bzip2 but worse than gzip
178 and LZO. Compression is slow.
179
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800180config KERNEL_LZO
181 bool "LZO"
182 depends on HAVE_KERNEL_LZO
183 help
Randy Dunlap0a4dd352012-05-31 16:26:46 -0700184 Its compression ratio is the poorest among the choices. The kernel
Stephan Sperber681b3042010-07-14 11:23:08 +0200185 size is about 10% bigger than gzip; however its speed
Albin Tonnerre7dd65fe2010-01-08 14:42:42 -0800186 (both compression and decompression) is the fastest.
187
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700188config KERNEL_LZ4
189 bool "LZ4"
190 depends on HAVE_KERNEL_LZ4
191 help
192 LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
193 A preliminary version of LZ4 de/compression tool is available at
194 <https://code.google.com/p/lz4/>.
195
196 Its compression ratio is worse than LZO. The size of the kernel
197 is about 8% bigger than LZO. But the decompression speed is
198 faster than LZO.
199
Alain Knaff30d65db2009-01-04 22:46:17 +0100200endchoice
201
Josh Triplettbd5dc172011-06-15 15:08:28 -0700202config DEFAULT_HOSTNAME
203 string "Default hostname"
204 default "(none)"
205 help
206 This option determines the default system hostname before userspace
207 calls sethostname(2). The kernel traditionally uses "(none)" here,
208 but you may wish to use a different default here to make a minimal
209 system more usable with less configuration.
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211config SWAP
212 bool "Support for paging of anonymous memory (swap)"
David Howells93614012006-09-30 20:45:40 +0200213 depends on MMU && BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 default y
215 help
216 This option allows you to choose whether you want to have support
Jesper Juhl92c35042006-01-15 02:40:08 +0100217 for so called swap devices or swap files in your kernel that are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 used to provide more virtual memory than the actual RAM present
219 in your computer. If unsure say Y.
220
221config SYSVIPC
222 bool "System V IPC"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 ---help---
224 Inter Process Communication is a suite of library functions and
225 system calls which let processes (running programs) synchronize and
226 exchange information. It is generally considered to be a good thing,
227 and some programs won't run unless you say Y here. In particular, if
228 you want to run the DOS emulator dosemu under Linux (read the
229 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
230 you'll need to say Y here.
231
232 You can find documentation about IPC with "info ipc" and also in
233 section 6.4 of the Linux Programmer's Guide, available from
234 <http://www.tldp.org/guides.html>.
235
Eric W. Biedermana5494dc2007-02-14 00:34:06 -0800236config SYSVIPC_SYSCTL
237 bool
238 depends on SYSVIPC
239 depends on SYSCTL
240 default y
241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242config POSIX_MQUEUE
243 bool "POSIX Message Queues"
Kees Cook19c92392012-10-02 11:19:29 -0700244 depends on NET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 ---help---
246 POSIX variant of message queues is a part of IPC. In POSIX message
247 queues every message has a priority which decides about succession
248 of receiving it by a process. If you want to compile and run
249 programs written e.g. for Solaris with use of its POSIX message
Robert P. J. Dayb0e37652007-05-09 07:25:13 +0200250 queues (functions mq_*) say Y here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252 POSIX message queues are visible as a filesystem called 'mqueue'
253 and can be mounted somewhere if you want to do filesystem
254 operations on message queues.
255
256 If unsure, say Y.
257
Serge E. Hallynbdc8e5f2009-04-06 19:01:11 -0700258config POSIX_MQUEUE_SYSCTL
259 bool
260 depends on POSIX_MQUEUE
261 depends on SYSCTL
262 default y
263
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700264config CROSS_MEMORY_ATTACH
265 bool "Enable process_vm_readv/writev syscalls"
266 depends on MMU
267 default y
268 help
269 Enabling this option adds the system calls process_vm_readv and
270 process_vm_writev which allow a process with the correct privileges
Geert Uytterhoevena2a368d2014-08-12 13:46:11 -0700271 to directly read from or write to another process' address space.
Konstantin Khlebnikov226b4cc2014-06-04 16:10:50 -0700272 See the man page for more details.
273
Aneesh Kumar K.V990d6c22011-01-29 18:43:26 +0530274config FHANDLE
275 bool "open by fhandle syscalls"
276 select EXPORTFS
277 help
278 If you say Y here, a user level program will be able to map
279 file names to handle and then later use the handle for
280 different file system operations. This is useful in implementing
281 userspace file servers, which now track files using handles instead
282 of names. The handle would remain the same even if file names
283 get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2)
284 syscalls.
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
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200377config IRQ_TIME_ACCOUNTING
378 bool "Fine granularity task level IRQ time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200379 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200380 help
381 Select this option to enable fine granularity task irq time
382 accounting. This is done by reading a timestamp on each
383 transitions between softirq and hardirq state, so there can be a
384 small performance impact.
385
386 If in doubt, say N here.
387
388endchoice
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
Mike Travisc903ff82009-01-15 12:28:29 -0800462menu "RCU Subsystem"
463
Mike Travisc903ff82009-01-15 12:28:29 -0800464config TREE_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400465 bool
466 default y if !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800467 help
468 This option selects the RCU implementation that is
469 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700470 thousands of CPUs. It also scales down nicely to
471 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800472
Pranith Kumar28f65692014-09-22 14:00:48 -0400473config PREEMPT_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400474 bool
475 default y if PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700476 help
477 This option selects the RCU implementation that is
478 designed for very large SMP systems with hundreds or
479 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700480 is also required. It also scales down nicely to
481 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700482
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800483 Select this option if you are unsure.
484
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700485config TINY_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400486 bool
487 default y if !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700488 help
489 This option selects the RCU implementation that is
490 designed for UP systems from which real-time response
491 is not required. This option greatly reduces the
492 memory footprint of RCU.
493
Paul E. McKenney78cae102015-04-20 12:19:45 -0700494config RCU_EXPERT
495 bool "Make expert-level adjustments to RCU configuration"
496 default n
497 help
498 This option needs to be enabled if you wish to make
499 expert-level adjustments to RCU configuration. By default,
500 no such adjustments can be made, which has the often-beneficial
501 side-effect of preventing "make oldconfig" from asking you all
502 sorts of detailed questions about how you would like numerous
503 obscure RCU options to be set up.
504
505 Say Y if you need to make expert-level adjustments to RCU.
506
507 Say N if you are unsure.
508
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500509config SRCU
510 bool
511 help
512 This option selects the sleepable version of RCU. This version
513 permits arbitrary sleeping or blocking within RCU read-side critical
514 sections.
515
Paul E. McKenney8315f422014-06-27 13:42:20 -0700516config TASKS_RCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -0700517 bool
Paul E. McKenney8315f422014-06-27 13:42:20 -0700518 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500519 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700520 help
521 This option enables a task-based RCU implementation that uses
522 only voluntary context switch (not preemption!), idle, and
523 user-mode execution as quiescent states.
524
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700525config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400526 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700527 help
528 This option enables RCU CPU stall code that is common between
529 the TINY and TREE variants of RCU. The purpose is to allow
530 the tiny variants to disable RCU CPU stall warnings, while
531 making these warnings mandatory for the tree variants.
532
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100533config CONTEXT_TRACKING
534 bool
535
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100536config CONTEXT_TRACKING_FORCE
537 bool "Force context tracking"
538 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200539 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200540 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200541 The major pre-requirement for full dynticks to work is to
542 support the context tracking subsystem. But there are also
543 other dependencies to provide in order to make the full
544 dynticks working.
545
546 This option stands for testing when an arch implements the
547 context tracking backend but doesn't yet fullfill all the
548 requirements to make the full dynticks feature working.
549 Without the full dynticks, there is no way to test the support
550 for context tracking and the subsystems that rely on it: RCU
551 userspace extended quiescent state and tickless cputime
552 accounting. This option copes with the absence of the full
553 dynticks subsystem by forcing the context tracking on all
554 CPUs in the system.
555
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400556 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200557 architecture backend for the context tracking.
558
559 Say N otherwise, this option brings an overhead that you
560 don't want in production.
561
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200562
Mike Travisc903ff82009-01-15 12:28:29 -0800563config RCU_FANOUT
564 int "Tree-based hierarchical RCU fanout value"
565 range 2 64 if 64BIT
566 range 2 32 if !64BIT
Paul E. McKenney05c5df32015-04-20 14:27:43 -0700567 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Mike Travisc903ff82009-01-15 12:28:29 -0800568 default 64 if 64BIT
569 default 32 if !64BIT
570 help
571 This option controls the fanout of hierarchical implementations
572 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700573 large numbers of CPUs. This value must be at least the fourth
574 root of NR_CPUS, which allows NR_CPUS to be insanely large.
575 The default value of RCU_FANOUT should be used for production
576 systems, but if you are stress-testing the RCU implementation
577 itself, small RCU_FANOUT values allow you to test large-system
578 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800579
580 Select a specific number if testing RCU itself.
581 Take the default if unsure.
582
Paul E. McKenney8932a632012-04-19 12:20:14 -0700583config RCU_FANOUT_LEAF
584 int "Tree-based hierarchical RCU leaf-level fanout value"
Paul E. McKenney8739c5c2015-04-20 18:27:54 -0700585 range 2 64 if 64BIT
586 range 2 32 if !64BIT
Paul E. McKenney47d631a2015-04-21 09:12:13 -0700587 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Paul E. McKenney8932a632012-04-19 12:20:14 -0700588 default 16
589 help
590 This option controls the leaf-level fanout of hierarchical
591 implementations of RCU, and allows trading off cache misses
592 against lock contention. Systems that synchronize their
593 scheduling-clock interrupts for energy-efficiency reasons will
594 want the default because the smaller leaf-level fanout keeps
595 lock contention levels acceptably low. Very large systems
596 (hundreds or thousands of CPUs) will instead want to set this
597 value to the maximum value possible in order to reduce the
598 number of cache misses incurred during RCU's grace-period
599 initialization. These systems tend to run CPU-bound, and thus
600 are not helped by synchronized interrupts, and thus tend to
601 skew them, which reduces lock contention enough that large
602 leaf-level fanouts work well.
603
604 Select a specific number if testing RCU itself.
605
606 Select the maximum permissible value for large systems.
607
608 Take the default if unsure.
609
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800610config RCU_FAST_NO_HZ
611 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700612 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800613 default n
614 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800615 This option permits CPUs to enter dynticks-idle state even if
616 they have RCU callbacks queued, and prevents RCU from waking
617 these CPUs up more than roughly once every four jiffies (by
618 default, you can adjust this using the rcutree.rcu_idle_gp_delay
619 parameter), thus improving energy efficiency. On the other
620 hand, this option increases the duration of RCU grace periods,
621 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800622
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800623 Say Y if energy efficiency is critically important, and you
624 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800625
626 Say N if you are unsure.
627
Mike Travisc903ff82009-01-15 12:28:29 -0800628config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400629 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800630 select DEBUG_FS
631 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700632 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400633 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700634 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800635
Paul E. McKenney24278d12010-09-27 17:25:23 -0700636config RCU_BOOST
637 bool "Enable RCU priority boosting"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700638 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700639 default n
640 help
641 This option boosts the priority of preempted RCU readers that
642 block the current preemptible RCU grace period for too long.
643 This option also prevents heavy loads from blocking RCU
644 callback invocation for all flavors of RCU.
645
646 Say Y here if you are working with real-time apps or heavy loads
647 Say N here if you are unsure.
648
Clark Williams21871d72014-09-12 21:21:09 -0500649config RCU_KTHREAD_PRIO
650 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800651 range 1 99 if RCU_BOOST
652 range 0 99 if !RCU_BOOST
653 default 1 if RCU_BOOST
654 default 0 if !RCU_BOOST
Paul E. McKenney26730f52015-04-21 09:22:14 -0700655 depends on RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700656 help
Clark Williams21871d72014-09-12 21:21:09 -0500657 This option specifies the SCHED_FIFO priority value that will be
658 assigned to the rcuc/n and rcub/n threads and is also the value
659 used for RCU_BOOST (if enabled). If you are working with a
660 real-time application that has one or more CPU-bound threads
661 running at a real-time priority level, you should set
662 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
663 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
664 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700665 applications that do not have any CPU-bound threads.
666
667 Some real-time applications might not have a single real-time
668 thread that saturates a given CPU, but instead might have
669 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500670 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700671 a priority higher than the lowest-priority thread that is
672 conspiring to prevent the CPU from running any non-real-time
673 tasks. For example, if one thread at priority 10 and another
674 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500675 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700676 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700677
678 Specify the real-time priority, or take the default if unsure.
679
680config RCU_BOOST_DELAY
681 int "Milliseconds to delay boosting after RCU grace-period start"
682 range 0 3000
683 depends on RCU_BOOST
684 default 500
685 help
686 This option specifies the time to wait after the beginning of
687 a given grace period before priority-boosting preempted RCU
688 readers blocking that grace period. Note that any RCU reader
689 blocking an expedited RCU grace period is boosted immediately.
690
691 Accept the default if unsure.
692
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700693config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700694 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400695 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenneybe55fa22015-06-02 05:29:18 -0700696 depends on RCU_EXPERT || NO_HZ_FULL
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700697 default n
698 help
699 Use this option to reduce OS jitter for aggressive HPC or
700 real-time workloads. It can also be used to offload RCU
701 callback invocation to energy-efficient CPUs in battery-powered
702 asymmetric multiprocessors.
703
704 This option offloads callback invocation from the set of
705 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800706 For each such CPU, a kthread ("rcuox/N") will be created to
707 invoke callbacks, where the "N" is the CPU being offloaded,
708 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
709 "s" for RCU-sched. Nothing prevents this kthread from running
710 on the specified CPUs, but (1) the kthreads may be preempted
711 between each callback, and (2) affinity or cgroups can be used
712 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700713
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800714 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700715 Say N here if you are unsure.
716
Paul E. McKenney911af502013-02-11 10:23:27 -0800717choice
718 prompt "Build-forced no-CBs CPUs"
719 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200720 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800721 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700722 This option allows no-CBs CPUs (whose RCU callbacks are invoked
723 from kthreads rather than from softirq context) to be specified
724 at build time. Additional no-CBs CPUs may be specified by
725 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800726
727config RCU_NOCB_CPU_NONE
728 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800729 help
730 This option does not force any of the CPUs to be no-CBs CPUs.
731 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700732 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
733 kthreads whose names begin with "rcuo". All other CPUs will
734 invoke their own RCU callbacks in softirq context.
735
736 Select this option if you want to choose no-CBs CPUs at
737 boot time, for example, to allow testing of different no-CBs
738 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800739
740config RCU_NOCB_CPU_ZERO
741 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800742 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700743 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
744 callbacks are invoked by a per-CPU kthread whose name begins
745 with "rcuo". Additional CPUs may be designated as no-CBs
746 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
747 All other CPUs will invoke their own RCU callbacks in softirq
748 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800749
750 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700751 or energy-efficiency reasons, but the real reason it exists
752 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800753
754config RCU_NOCB_CPU_ALL
755 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800756 help
757 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700758 boot parameter will be ignored. All CPUs' RCU callbacks will
759 be executed in the context of per-CPU rcuo kthreads created for
760 this purpose. Assuming that the kthreads whose names start with
761 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
762 on the remaining CPUs, but might decrease memory locality during
763 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800764
765 Select this if all CPUs need to be no-CBs CPUs for real-time
766 or energy-efficiency reasons.
767
768endchoice
769
Paul E. McKenneyee425712015-02-19 10:51:32 -0800770config RCU_EXPEDITE_BOOT
771 bool
772 default n
773 help
774 This option enables expedited grace periods at boot time,
775 as if rcu_expedite_gp() had been invoked early in boot.
776 The corresponding rcu_unexpedite_gp() is invoked from
777 rcu_end_inkernel_boot(), which is intended to be invoked
778 at the end of the kernel-only boot sequence, just before
779 init is exec'ed.
780
781 Accept the default if unsure.
782
Mike Travisc903ff82009-01-15 12:28:29 -0800783endmenu # "RCU Subsystem"
784
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700785config BUILD_BIN2C
786 bool
787 default n
788
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700790 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700791 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 ---help---
793 This option enables the complete Linux kernel ".config" file
794 contents to be saved in the kernel. It provides documentation
795 of which kernel options are used in a running kernel or in an
796 on-disk kernel. This information can be extracted from the kernel
797 image file with the script scripts/extract-ikconfig and used as
798 input to rebuild the current kernel or to build another kernel.
799 It can also be extracted from a running kernel by reading
800 /proc/config.gz if enabled (below).
801
802config IKCONFIG_PROC
803 bool "Enable access to .config through /proc/config.gz"
804 depends on IKCONFIG && PROC_FS
805 ---help---
806 This option enables access to the kernel configuration file
807 through /proc/config.gz.
808
Alistair John Strachan794543a2007-05-08 00:31:15 -0700809config LOG_BUF_SHIFT
810 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Ingo Molnarfb39f982015-07-01 10:19:11 +0200811 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700812 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700813 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700814 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700815 Select the minimal kernel log buffer size as a power of 2.
816 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
817 parameter, see below. Any higher size also might be forced
818 by "log_buf_len" boot parameter.
819
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700820 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700821 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700822 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700823 15 => 32 KB
824 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700825 13 => 8 KB
826 12 => 4 KB
827
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700828config LOG_CPU_MAX_BUF_SHIFT
829 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700830 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700831 range 0 21
832 default 12 if !BASE_SMALL
833 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700834 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700835 help
836 This option allows to increase the default ring buffer size
837 according to the number of CPUs. The value defines the contribution
838 of each CPU as a power of 2. The used space is typically only few
839 lines however it might be much more when problems are reported,
840 e.g. backtraces.
841
842 The increased size means that a new buffer has to be allocated and
843 the original static one is unused. It makes sense only on systems
844 with more CPUs. Therefore this value is used only when the sum of
845 contributions is greater than the half of the default kernel ring
846 buffer as defined by LOG_BUF_SHIFT. The default values are set
847 so that more than 64 CPUs are needed to trigger the allocation.
848
849 Also this option is ignored when "log_buf_len" kernel parameter is
850 used as it forces an exact (power of two) size of the ring buffer.
851
852 The number of possible CPUs is used for this computation ignoring
853 hotplugging making the compuation optimal for the the worst case
854 scenerio while allowing a simple algorithm to be used from bootup.
855
856 Examples shift values and their meaning:
857 17 => 128 KB for each CPU
858 16 => 64 KB for each CPU
859 15 => 32 KB for each CPU
860 14 => 16 KB for each CPU
861 13 => 8 KB for each CPU
862 12 => 4 KB for each CPU
863
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800864#
865# Architectures with an unreliable sched_clock() should select this:
866#
867config HAVE_UNSTABLE_SCHED_CLOCK
868 bool
869
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700870config GENERIC_SCHED_CLOCK
871 bool
872
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200873#
874# For architectures that want to enable the support for NUMA-affine scheduler
875# balancing logic:
876#
877config ARCH_SUPPORTS_NUMA_BALANCING
878 bool
879
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100880#
Mel Gorman72b252a2015-09-04 15:47:32 -0700881# For architectures that prefer to flush all TLBs after a number of pages
882# are unmapped instead of sending one IPI per page to flush. The architecture
883# must provide guarantees on what happens if a clean TLB cache entry is
884# written after the unmap. Details are in mm/rmap.c near the check for
885# should_defer_flush. The architecture should also consider if the full flush
886# and the refill costs are offset by the savings of sending fewer IPIs.
887config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
888 bool
889
890#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100891# For architectures that know their GCC __int128 support is sound
892#
893config ARCH_SUPPORTS_INT128
894 bool
895
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200896# For architectures that (ab)use NUMA to represent different memory regions
897# all cpu-local but of different latencies, such as SuperH.
898#
899config ARCH_WANT_NUMA_VARIABLE_LOCALITY
900 bool
901
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200902config NUMA_BALANCING
903 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200904 depends on ARCH_SUPPORTS_NUMA_BALANCING
905 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
906 depends on SMP && NUMA && MIGRATION
907 help
908 This option adds support for automatic NUMA aware memory/task placement.
909 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400910 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200911
912 This system will be inactive on UMA systems.
913
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800914config NUMA_BALANCING_DEFAULT_ENABLED
915 bool "Automatically enable NUMA aware memory/task placement"
916 default y
917 depends on NUMA_BALANCING
918 help
919 If set, automatic NUMA balancing will be enabled if running on a NUMA
920 machine.
921
Li Zefan23964d22009-01-15 13:50:58 -0800922menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500923 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500924 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700925 help
Li Zefan23964d22009-01-15 13:50:58 -0800926 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800927 use with process control subsystems such as Cpusets, CFS, memory
928 controls or device isolation.
929 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800930 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800931 - Documentation/cgroups/ (features for grouping, isolation
932 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700933
934 Say N if unsure.
935
Li Zefan23964d22009-01-15 13:50:58 -0800936if CGROUPS
937
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800938config PAGE_COUNTER
939 bool
940
Andrew Mortonc255a452012-07-31 16:43:02 -0700941config MEMCG
Johannes Weinera0166ec2015-12-17 17:19:56 -0500942 bool "Memory controller"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800943 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500944 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800945 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500946 Provides control over the memory footprint of tasks in a cgroup.
Balbir Singh00f0b822008-03-04 14:28:39 -0800947
Andrew Mortonc255a452012-07-31 16:43:02 -0700948config MEMCG_SWAP
Johannes Weinera0166ec2015-12-17 17:19:56 -0500949 bool "Swap controller"
Andrew Mortonc255a452012-07-31 16:43:02 -0700950 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800951 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500952 Provides control over the swap space consumed by tasks in a cgroup.
953
Andrew Mortonc255a452012-07-31 16:43:02 -0700954config MEMCG_SWAP_ENABLED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500955 bool "Swap controller enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700956 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800957 default y
958 help
959 Memory Resource Controller Swap Extension comes with its price in
960 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700961 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -0700962 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -0800963 parameter should have this option unselected.
964 For those who want to have the feature enabled by default should
965 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700966 then swapaccount=0 does the trick).
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800967
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500968config BLK_CGROUP
969 bool "IO controller"
970 depends on BLOCK
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700971 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500972 ---help---
973 Generic block IO controller cgroup interface. This is the common
974 cgroup interface which should be used by various IO controlling
975 policies.
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700976
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500977 Currently, CFQ IO scheduler uses it to recognize task groups and
978 control disk bandwidth allocation (proportional time slice allocation)
979 to such task groups. It is also used by bio throttling logic in
980 block layer to implement upper limit in IO rates on a device.
Stephane Eraniane5d13672011-02-14 11:20:01 +0200981
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500982 This option only enables generic Block IO controller infrastructure.
983 One needs to also enable actual IO controlling logic/policy. For
984 enabling proportional weight division of disk bandwidth in CFQ, set
985 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
986 CONFIG_BLK_DEV_THROTTLING=y.
987
988 See Documentation/cgroups/blkio-controller.txt for more information.
989
990config DEBUG_BLK_CGROUP
991 bool "IO controller debugging"
992 depends on BLK_CGROUP
993 default n
994 ---help---
995 Enable some debugging help. Currently it exports additional stat
996 files in a cgroup which can be useful for debugging.
997
998config CGROUP_WRITEBACK
999 bool
1000 depends on MEMCG && BLK_CGROUP
1001 default y
Stephane Eraniane5d13672011-02-14 11:20:01 +02001002
Dhaval Giani7c941432010-01-20 13:26:18 +01001003menuconfig CGROUP_SCHED
Johannes Weinera0166ec2015-12-17 17:19:56 -05001004 bool "CPU controller"
Dhaval Giani7c941432010-01-20 13:26:18 +01001005 default n
1006 help
1007 This feature lets CPU scheduler recognize task groups and control CPU
1008 bandwidth allocation to such task groups. It uses cgroups to group
1009 tasks.
1010
1011if CGROUP_SCHED
1012config FAIR_GROUP_SCHED
1013 bool "Group scheduling for SCHED_OTHER"
1014 depends on CGROUP_SCHED
1015 default CGROUP_SCHED
1016
Paul Turnerab84d312011-07-21 09:43:28 -07001017config CFS_BANDWIDTH
1018 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001019 depends on FAIR_GROUP_SCHED
1020 default n
1021 help
1022 This option allows users to define CPU bandwidth rates (limits) for
1023 tasks running within the fair group scheduler. Groups with no limit
1024 set are considered to be unconstrained and will run with no
1025 restriction.
1026 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1027
Dhaval Giani7c941432010-01-20 13:26:18 +01001028config RT_GROUP_SCHED
1029 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001030 depends on CGROUP_SCHED
1031 default n
1032 help
1033 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001034 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001035 schedule realtime tasks for non-root users until you allocate
1036 realtime bandwidth for them.
1037 See Documentation/scheduler/sched-rt-group.txt for more information.
1038
1039endif #CGROUP_SCHED
1040
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001041config CGROUP_PIDS
1042 bool "PIDs controller"
1043 help
1044 Provides enforcement of process number limits in the scope of a
1045 cgroup. Any attempt to fork more processes than is allowed in the
1046 cgroup will fail. PIDs are fundamentally a global resource because it
1047 is fairly trivial to reach PID exhaustion before you reach even a
1048 conservative kmemcg limit. As a result, it is possible to grind a
1049 system to halt without being limited by other cgroup policies. The
1050 PIDs cgroup subsystem is designed to stop this from happening.
1051
1052 It should be noted that organisational operations (such as attaching
1053 to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
1054 since the PIDs limit only affects a process's ability to fork, not to
1055 attach to a cgroup.
1056
1057config CGROUP_FREEZER
1058 bool "Freezer controller"
1059 help
1060 Provides a way to freeze and unfreeze all tasks in a
1061 cgroup.
1062
Johannes Weiner489c2a22016-01-20 15:02:41 -08001063 This option affects the ORIGINAL cgroup interface. The cgroup2 memory
1064 controller includes important in-kernel memory consumers per default.
1065
1066 If you're using cgroup2, say N.
1067
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001068config CGROUP_HUGETLB
1069 bool "HugeTLB controller"
1070 depends on HUGETLB_PAGE
1071 select PAGE_COUNTER
Vivek Goyalafc24d42010-04-26 19:27:56 +02001072 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001073 help
1074 Provides a cgroup controller for HugeTLB pages.
1075 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1076 The limit is enforced during page fault. Since HugeTLB doesn't
1077 support page reclaim, enforcing the limit at page fault time implies
1078 that, the application will get SIGBUS signal if it tries to access
1079 HugeTLB pages beyond its limit. This requires the application to know
1080 beforehand how much HugeTLB pages it would require for its use. The
1081 control group is tracked in the third page lru pointer. This means
1082 that we cannot use the controller with huge page less than 3 pages.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001083
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001084config CPUSETS
1085 bool "Cpuset controller"
1086 help
1087 This option will let you create and manage CPUSETs which
1088 allow dynamically partitioning a system into sets of CPUs and
1089 Memory Nodes and assigning tasks to run only within those sets.
1090 This is primarily useful on large SMP or NUMA systems.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001091
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001092 Say N if unsure.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001093
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001094config PROC_PID_CPUSET
1095 bool "Include legacy /proc/<pid>/cpuset file"
1096 depends on CPUSETS
Tejun Heo89e9b9e2015-05-22 17:13:36 -04001097 default y
1098
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001099config CGROUP_DEVICE
1100 bool "Device controller"
1101 help
1102 Provides a cgroup controller implementing whitelists for
1103 devices which a process in the cgroup can mknod or open.
1104
1105config CGROUP_CPUACCT
1106 bool "Simple CPU accounting controller"
1107 help
1108 Provides a simple controller for monitoring the
1109 total CPU consumed by the tasks in a cgroup.
1110
1111config CGROUP_PERF
1112 bool "Perf controller"
1113 depends on PERF_EVENTS
1114 help
1115 This option extends the perf per-cpu mode to restrict monitoring
1116 to threads which belong to the cgroup specified and run on the
1117 designated cpu.
1118
1119 Say N if unsure.
1120
1121config CGROUP_DEBUG
1122 bool "Example controller"
1123 default n
1124 help
1125 This option enables a simple controller that exports
1126 debugging information about the cgroups framework.
1127
1128 Say N.
1129
Li Zefan23964d22009-01-15 13:50:58 -08001130endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001131
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001132config CHECKPOINT_RESTORE
1133 bool "Checkpoint/restore support" if EXPERT
Iago López Galeiras2e13ba52015-06-25 15:00:57 -07001134 select PROC_CHILDREN
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001135 default n
1136 help
1137 Enables additional kernel features in a sake of checkpoint/restore.
1138 In particular it adds auxiliary prctl codes to setup process text,
1139 data and heap segment sizes, and a few additional /proc filesystem
1140 entries.
1141
1142 If unsure, say N here.
1143
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001144menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001145 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001146 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001147 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001148 help
1149 Provides the way to make tasks work with different objects using
1150 the same id. For example same IPC id may refer to different objects
1151 or same user id or pid may refer to different tasks when used in
1152 different namespaces.
1153
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001154if NAMESPACES
1155
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001156config UTS_NS
1157 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001158 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001159 help
1160 In this namespace tasks see different info provided with the
1161 uname() system call
1162
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001163config IPC_NS
1164 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001165 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001166 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001167 help
1168 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001169 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001170
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001171config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001172 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001173 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001174 help
1175 This allows containers, i.e. vservers, to use user namespaces
1176 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001177
1178 When user namespaces are enabled in the kernel it is
Johannes Weinerd886f4e2016-01-20 15:02:47 -08001179 recommended that the MEMCG option also be enabled and that
1180 user-space use the memory control groups to limit the amount
1181 of memory a memory unprivileged users can use.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001182
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001183 If unsure, say N.
1184
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001185config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001186 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001187 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001188 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001189 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001190 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001191 pid namespaces. This is a building block of containers.
1192
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001193config NET_NS
1194 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001195 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001196 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001197 help
1198 Allow user space to create what appear to be multiple instances
1199 of the network stack.
1200
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001201endif # NAMESPACES
1202
Mike Galbraith5091faa2010-11-30 14:18:03 +01001203config SCHED_AUTOGROUP
1204 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001205 select CGROUPS
1206 select CGROUP_SCHED
1207 select FAIR_GROUP_SCHED
1208 help
1209 This option optimizes the scheduler for common desktop workloads by
1210 automatically creating and populating task groups. This separation
1211 of workloads isolates aggressive CPU burners (like build jobs) from
1212 desktop applications. Task group autogeneration is currently based
1213 upon task session.
1214
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001215config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001216 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001217 depends on SYSFS
1218 default n
1219 help
1220 This option adds code that switches the layout of the "block" class
1221 devices, to not show up in /sys/class/block/, but only in
1222 /sys/block/.
1223
1224 This switch is only active when the sysfs.deprecated=1 boot option is
1225 passed or the SYSFS_DEPRECATED_V2 option is set.
1226
1227 This option allows new kernels to run on old distributions and tools,
1228 which might get confused by /sys/class/block/. Since 2007/2008 all
1229 major distributions and tools handle this just fine.
1230
1231 Recent distributions and userspace tools after 2009/2010 depend on
1232 the existence of /sys/class/block/, and will not work with this
1233 option enabled.
1234
1235 Only if you are using a new kernel on an old distribution, you might
1236 need to say Y here.
1237
1238config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001239 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001240 default n
1241 depends on SYSFS
1242 depends on SYSFS_DEPRECATED
1243 help
1244 Enable deprecated sysfs by default.
1245
1246 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1247 option.
1248
1249 Only if you are using a new kernel on an old distribution, you might
1250 need to say Y here. Even then, odds are you would not need it
1251 enabled, you can always pass the boot option if absolutely necessary.
1252
1253config RELAY
1254 bool "Kernel->user space relay support (formerly relayfs)"
1255 help
1256 This option enables support for relay interface support in
1257 certain file systems (such as debugfs).
1258 It is designed to provide an efficient mechanism for tools and
1259 facilities to relay large amounts of data from kernel space to
1260 user space.
1261
1262 If unsure, say N.
1263
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001264config BLK_DEV_INITRD
1265 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1266 depends on BROKEN || !FRV
1267 help
1268 The initial RAM filesystem is a ramfs which is loaded by the
1269 boot loader (loadlin or lilo) and that is mounted as root
1270 before the normal boot procedure. It is typically used to
1271 load modules needed to mount the "real" root file system,
1272 etc. See <file:Documentation/initrd.txt> for details.
1273
1274 If RAM disk support (BLK_DEV_RAM) is also included, this
1275 also enables initial RAM disk (initrd) support and adds
1276 15 Kbytes (more on some other architectures) to the kernel size.
1277
1278 If unsure say Y.
1279
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001280if BLK_DEV_INITRD
1281
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001282source "usr/Kconfig"
1283
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001284endif
1285
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001286config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001287 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001288 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001289 Enabling this option will pass "-Os" instead of "-O2" to
1290 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001291
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001292 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001293
Randy Dunlap08470622006-09-30 23:28:13 -07001294config SYSCTL
1295 bool
1296
Randy Dunlapb943c462009-03-10 12:55:46 -07001297config ANON_INODES
1298 bool
1299
Mike Frysinger657a5202013-04-30 15:28:45 -07001300config HAVE_UID16
1301 bool
1302
1303config SYSCTL_EXCEPTION_TRACE
1304 bool
1305 help
1306 Enable support for /proc/sys/debug/exception-trace.
1307
1308config SYSCTL_ARCH_UNALIGN_NO_WARN
1309 bool
1310 help
1311 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1312 Allows arch to define/use @no_unaligned_warning to possibly warn
1313 about unaligned access emulation going on under the hood.
1314
1315config SYSCTL_ARCH_UNALIGN_ALLOW
1316 bool
1317 help
1318 Enable support for /proc/sys/kernel/unaligned-trap
1319 Allows arches to define/use @unaligned_enabled to runtime toggle
1320 the unaligned access emulation.
1321 see arch/parisc/kernel/unaligned.c for reference
1322
Mike Frysinger657a5202013-04-30 15:28:45 -07001323config HAVE_PCSPKR_PLATFORM
1324 bool
1325
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001326# interpreter that classic socket filters depend on
1327config BPF
1328 bool
1329
David Rientjes6a108a12011-01-20 14:44:16 -08001330menuconfig EXPERT
1331 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001332 # Unhide debug options, to make the on-by-default options visible
1333 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 help
1335 This option allows certain base kernel options and settings
1336 to be disabled or tweaked. This is for specialized
1337 environments which can tolerate a "non-standard" kernel.
1338 Only use this if you really know what you are doing.
1339
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001340config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001341 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001342 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001343 default y
1344 help
1345 This enables the legacy 16-bit UID syscall wrappers.
1346
Iulia Manda28138932015-04-15 16:16:41 -07001347config MULTIUSER
1348 bool "Multiple users, groups and capabilities support" if EXPERT
1349 default y
1350 help
1351 This option enables support for non-root users, groups and
1352 capabilities.
1353
1354 If you say N here, all processes will run with UID 0, GID 0, and all
1355 possible capabilities. Saying N here also compiles out support for
1356 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1357 setgid, and capset.
1358
1359 If unsure, say Y here.
1360
Fabian Frederickf6187762014-06-04 16:11:12 -07001361config SGETMASK_SYSCALL
1362 bool "sgetmask/ssetmask syscalls support" if EXPERT
1363 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1364 ---help---
1365 sys_sgetmask and sys_ssetmask are obsolete system calls
1366 no longer supported in libc but still enabled by default in some
1367 architectures.
1368
1369 If unsure, leave the default option here.
1370
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001371config SYSFS_SYSCALL
1372 bool "Sysfs syscall support" if EXPERT
1373 default y
1374 ---help---
1375 sys_sysfs is an obsolete system call no longer supported in libc.
1376 Note that disabling this option is more secure but might break
1377 compatibility with some systems.
1378
1379 If unsure say Y here.
1380
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001381config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001382 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001383 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001384 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001385 select SYSCTL
1386 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001387 sys_sysctl uses binary paths that have been found challenging
1388 to properly maintain and use. The interface in /proc/sys
1389 using paths with ascii names is now the primary path to this
1390 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001391
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001392 Almost nothing using the binary sysctl interface so if you are
1393 trying to save some space it is probably safe to disable this,
1394 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001395
WANG Congc736de62011-11-02 13:39:25 -07001396 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001397
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001399 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 default y
1401 help
1402 Say Y here to let the kernel print out symbolic crash information and
1403 symbolic stack backtraces. This increases the size of the kernel
1404 somewhat, as all symbols have to be loaded into the kernel image.
1405
1406config KALLSYMS_ALL
1407 bool "Include all symbols in kallsyms"
1408 depends on DEBUG_KERNEL && KALLSYMS
1409 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001410 Normally kallsyms only contains the symbols of functions for nicer
1411 OOPS messages and backtraces (i.e., symbols from the text and inittext
1412 sections). This is sufficient for most cases. And only in very rare
1413 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1414 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001416 This option makes sure that all symbols are loaded into the kernel
1417 image (i.e., symbols from all sections) in cost of increased kernel
1418 size (depending on the kernel configuration, it may be 300KiB or
1419 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001421 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001422
Ard Biesheuvel4d5d5662016-03-15 14:58:12 -07001423config KALLSYMS_ABSOLUTE_PERCPU
1424 bool
1425 default X86_64 && SMP
1426
Ard Biesheuvel2213e9a2016-03-15 14:58:19 -07001427config KALLSYMS_BASE_RELATIVE
1428 bool
1429 depends on KALLSYMS
1430 default !IA64 && !(TILE && 64BIT)
1431 help
1432 Instead of emitting them as absolute values in the native word size,
1433 emit the symbol references in the kallsyms table as 32-bit entries,
1434 each containing a relative value in the range [base, base + U32_MAX]
1435 or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either
1436 an absolute value in the range [0, S32_MAX] or a relative value in the
1437 range [base, base + S32_MAX], where base is the lowest relative symbol
1438 address encountered in the image.
1439
1440 On 64-bit builds, this reduces the size of the address table by 50%,
1441 but more importantly, it results in entries whose values are build
1442 time constants, and no relocation pass is required at runtime to fix
1443 up the entries based on the runtime load address of the kernel.
1444
Matt Mackalld59745c2005-05-01 08:59:02 -07001445config PRINTK
1446 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001447 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001448 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001449 help
1450 This option enables normal printk support. Removing it
1451 eliminates most of the message strings from the kernel image
1452 and makes the kernel more or less silent. As this makes it
1453 very difficult to diagnose system problems, saying N here is
1454 strongly discouraged.
1455
Matt Mackallc8538a72005-05-01 08:59:01 -07001456config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001457 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001458 default y
1459 help
1460 Disabling this option eliminates support for BUG and WARN, reducing
1461 the size of your kernel image and potentially quietly ignoring
1462 numerous fatal conditions. You should only consider disabling this
1463 option for embedded systems with no facilities for reporting errors.
1464 Just say Y.
1465
Matt Mackall708e9a72006-01-08 01:05:25 -08001466config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001467 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001468 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001469 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001470 help
1471 Enable support for generating core dumps. Disabling saves about 4k.
1472
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001473
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001474config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001475 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001476 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001477 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001478 default y
1479 help
1480 This option allows to disable the internal PC-Speaker
1481 support, saving some memory.
1482
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483config BASE_FULL
1484 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001485 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 help
1487 Disabling this option reduces the size of miscellaneous core
1488 kernel data structures. This saves memory on small machines,
1489 but may reduce performance.
1490
1491config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001492 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001494 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 help
1496 Disabling this option will cause the kernel to be built without
1497 support for "fast userspace mutexes". The resulting kernel may not
1498 run glibc-based applications correctly.
1499
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001500config HAVE_FUTEX_CMPXCHG
1501 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001502 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001503 help
1504 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1505 is implemented and always working. This removes a couple of runtime
1506 checks.
1507
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001509 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001511 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512 help
1513 Disabling this option will cause the kernel to be built without
1514 support for epoll family of system calls.
1515
Davide Libenzifba2afa2007-05-10 22:23:13 -07001516config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001517 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001518 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001519 default y
1520 help
1521 Enable the signalfd() system call that allows to receive signals
1522 on a file descriptor.
1523
1524 If unsure, say Y.
1525
Davide Libenzib215e282007-05-10 22:23:16 -07001526config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001527 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001528 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001529 default y
1530 help
1531 Enable the timerfd() system call that allows to receive timer
1532 events on a file descriptor.
1533
1534 If unsure, say Y.
1535
Davide Libenzie1ad7462007-05-10 22:23:19 -07001536config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001537 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001538 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001539 default y
1540 help
1541 Enable the eventfd() system call that allows to receive both
1542 kernel notification (ie. KAIO) or userspace notifications.
1543
1544 If unsure, say Y.
1545
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001546# syscall, maps, verifier
1547config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001548 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001549 select ANON_INODES
1550 select BPF
1551 default n
1552 help
1553 Enable the bpf() system call that allows to manipulate eBPF
1554 programs and maps via file descriptors.
1555
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001557 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 default y
1559 depends on MMU
1560 help
1561 The shmem is an internal filesystem used to manage shared memory.
1562 It is backed by swap and manages resource limits. It is also exported
1563 to userspace as tmpfs if TMPFS is enabled. Disabling this
1564 option replaces shmem and tmpfs with the much simpler ramfs code,
1565 which may be appropriate on small systems without swap.
1566
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001567config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001568 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001569 default y
1570 help
1571 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001572 by some high performance threaded applications. Disabling
1573 this option saves about 7k.
1574
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001575config ADVISE_SYSCALLS
1576 bool "Enable madvise/fadvise syscalls" if EXPERT
1577 default y
1578 help
1579 This option enables the madvise and fadvise syscalls, used by
1580 applications to advise the kernel about their future memory or file
1581 usage, improving performance. If building an embedded system where no
1582 applications use these syscalls, you can disable this option to save
1583 space.
1584
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001585config USERFAULTFD
1586 bool "Enable userfaultfd() system call"
1587 select ANON_INODES
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001588 depends on MMU
1589 help
1590 Enable the userfaultfd() system call that allows to intercept and
1591 handle page faults in userland.
1592
Mike Frysinger657a5202013-04-30 15:28:45 -07001593config PCI_QUIRKS
1594 default y
1595 bool "Enable PCI quirk workarounds" if EXPERT
1596 depends on PCI
1597 help
1598 This enables workarounds for various PCI chipset
1599 bugs/quirks. Disable this only if your target machine is
1600 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001601
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001602config MEMBARRIER
1603 bool "Enable membarrier() system call" if EXPERT
1604 default y
1605 help
1606 Enable the membarrier() system call that allows issuing memory
1607 barriers across all running threads, which can be used to distribute
1608 the cost of user-space memory barriers asymmetrically by transforming
1609 pairs of memory barriers into pairs consisting of membarrier() and a
1610 compiler barrier.
1611
1612 If unsure, say Y.
1613
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001614config EMBEDDED
1615 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001616 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001617 select EXPERT
1618 help
1619 This option should be enabled if compiling the kernel for
1620 an embedded system so certain expert options are available
1621 for configuration.
1622
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001623config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001624 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001625 help
1626 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001627
Peter Zijlstra906010b2009-09-21 16:08:49 +02001628config PERF_USE_VMALLOC
1629 bool
1630 help
1631 See tools/perf/design.txt for details
1632
Ingo Molnar57c0c152009-09-21 12:20:38 +02001633menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001634
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001635config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001636 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001637 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001638 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001639 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001640 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001641 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001642 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001643 Enable kernel support for various performance events provided
1644 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001645
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001646 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001647 use of generic tracepoints.
1648
1649 Most modern CPUs support performance events via performance
1650 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001651 types of hw events: such as instructions executed, cachemisses
1652 suffered, or branches mis-predicted - without slowing down the
1653 kernel or applications. These registers can also trigger interrupts
1654 when a threshold number of events have passed - and can thus be
1655 used to profile the code that runs on that CPU.
1656
Ingo Molnar57c0c152009-09-21 12:20:38 +02001657 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001658 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001659 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001660 provides per task and per CPU counters, and it provides event
1661 capabilities on top of those.
1662
1663 Say Y if unsure.
1664
Peter Zijlstra906010b2009-09-21 16:08:49 +02001665config DEBUG_PERF_USE_VMALLOC
1666 default n
1667 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001668 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001669 select PERF_USE_VMALLOC
1670 help
1671 Use vmalloc memory to back perf mmap() buffers.
1672
1673 Mostly useful for debugging the vmalloc code on platforms
1674 that don't require it.
1675
1676 Say N if unsure.
1677
Thomas Gleixner0793a612008-12-04 20:12:29 +01001678endmenu
1679
Christoph Lameterf8891e52006-06-30 01:55:45 -07001680config VM_EVENT_COUNTERS
1681 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001682 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001683 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001684 VM event counters are needed for event counts to be shown.
1685 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001686 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001687 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001688
Christoph Lameter41ecc552007-05-09 02:32:44 -07001689config SLUB_DEBUG
1690 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001691 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001692 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001693 help
1694 SLUB has extensive debug support features. Disabling these can
1695 result in significant savings in code size. This also disables
1696 SLUB sysfs support. /sys/slab will not exist and there will be
1697 no support for cache validation etc.
1698
Randy Dunlapb943c462009-03-10 12:55:46 -07001699config COMPAT_BRK
1700 bool "Disable heap randomization"
1701 default y
1702 help
1703 Randomizing heap placement makes heap exploits harder, but it
1704 also breaks ancient binaries (including anything libc5 based).
1705 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001706 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001707 /proc/sys/kernel/randomize_va_space to 2.
1708
1709 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1710
Christoph Lameter81819f02007-05-06 14:49:36 -07001711choice
1712 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001713 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001714 help
1715 This option allows to select a slab allocator.
1716
1717config SLAB
1718 bool "SLAB"
1719 help
1720 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001721 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001722 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001723
1724config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001725 bool "SLUB (Unqueued Allocator)"
1726 help
1727 SLUB is a slab allocator that minimizes cache line usage
1728 instead of managing queues of cached objects (SLAB approach).
1729 Per cpu caching is realized using slabs of objects instead
1730 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001731 and has enhanced diagnostics. SLUB is the default choice for
1732 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001733
1734config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001735 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001736 bool "SLOB (Simple Allocator)"
1737 help
Matt Mackall37291452008-02-04 22:29:38 -08001738 SLOB replaces the stock allocator with a drastically simpler
1739 allocator. SLOB is generally more space efficient but
1740 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001741
1742endchoice
1743
Joonsoo Kim345c9052013-06-19 14:05:52 +09001744config SLUB_CPU_PARTIAL
1745 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001746 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001747 bool "SLUB per cpu partial cache"
1748 help
1749 Per cpu partial caches accellerate objects allocation and freeing
1750 that is local to a processor at the price of more indeterminism
1751 in the latency of the free. On overflow these caches will be cleared
1752 which requires the taking of locks that may cause latency spikes.
1753 Typically one would choose no for a realtime system.
1754
Jie Zhangea637632009-12-14 18:00:02 -08001755config MMAP_ALLOW_UNINITIALIZED
1756 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001757 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001758 default n
1759 help
1760 Normally, and according to the Linux spec, anonymous memory obtained
1761 from mmap() has it's contents cleared before it is passed to
1762 userspace. Enabling this config option allows you to request that
1763 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1764 providing a huge performance boost. If this option is not enabled,
1765 then the flag will be ignored.
1766
1767 This is taken advantage of by uClibc's malloc(), and also by
1768 ELF-FDPIC binfmt's brk and stack allocator.
1769
1770 Because of the obvious security issues, this option should only be
1771 enabled on embedded devices where you control what is run in
1772 userspace. Since that isn't generally a problem on no-MMU systems,
1773 it is normally safe to say Y here.
1774
1775 See Documentation/nommu-mmap.txt for more information.
1776
David Howells091f6e22015-07-20 21:16:28 +01001777config SYSTEM_DATA_VERIFICATION
1778 def_bool n
1779 select SYSTEM_TRUSTED_KEYRING
1780 select KEYS
1781 select CRYPTO
1782 select ASYMMETRIC_KEY_TYPE
1783 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1784 select PUBLIC_KEY_ALGO_RSA
1785 select ASN1
1786 select OID_REGISTRY
1787 select X509_CERTIFICATE_PARSER
1788 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001789 help
David Howells091f6e22015-07-20 21:16:28 +01001790 Provide PKCS#7 message verification using the contents of the system
1791 trusted keyring to provide public keys. This then can be used for
1792 module verification, kexec image verification and firmware blob
1793 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001794
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001795config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001796 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001797 help
1798 Say Y here to enable the extended profiling support mechanisms used
1799 by profilers such as OProfile.
1800
Ingo Molnar5f87f112008-07-23 14:15:22 +02001801#
1802# Place an empty function call at each tracepoint site. Can be
1803# dynamically changed for a probe function.
1804#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001805config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001806 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001807
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001808source "arch/Kconfig"
1809
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810endmenu # General setup
1811
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001812config HAVE_GENERIC_DMA_COHERENT
1813 bool
1814 default n
1815
Linus Torvalds158a9622008-01-02 13:04:48 -08001816config SLABINFO
1817 bool
1818 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001819 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001820 default y
1821
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001822config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001823 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001824
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825config BASE_SMALL
1826 int
1827 default 0 if BASE_FULL
1828 default 1 if !BASE_FULL
1829
Jan Engelhardt66da5732007-07-15 23:39:29 -07001830menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001832 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 help
1834 Kernel modules are small pieces of compiled code which can
1835 be inserted in the running kernel, rather than being
1836 permanently built into the kernel. You use the "modprobe"
1837 tool to add (and sometimes remove) them. If you say Y here,
1838 many parts of the kernel can be built as modules (by
1839 answering M instead of Y where indicated): this is most
1840 useful for infrequently used options which are not required
1841 for booting. For more information, see the man pages for
1842 modprobe, lsmod, modinfo, insmod and rmmod.
1843
1844 If you say Y here, you will need to run "make
1845 modules_install" to put the modules under /lib/modules/
1846 where modprobe can find them (you may need to be root to do
1847 this).
1848
1849 If unsure, say Y.
1850
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001851if MODULES
1852
Linus Torvalds826e4502008-05-04 17:04:16 -07001853config MODULE_FORCE_LOAD
1854 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001855 default n
1856 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001857 Allow loading of modules without version information (ie. modprobe
1858 --force). Forced module loading sets the 'F' (forced) taint flag and
1859 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001860
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861config MODULE_UNLOAD
1862 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 help
1864 Without this option you will not be able to unload any
1865 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001866 anyway), which makes your kernel smaller, faster
1867 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868
1869config MODULE_FORCE_UNLOAD
1870 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001871 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 help
1873 This option allows you to force a module to unload, even if the
1874 kernel believes it is unsafe: the kernel will remove the module
1875 without waiting for anyone to stop using it (using the -f option to
1876 rmmod). This is mainly for kernel developers and desperate users.
1877 If unsure, say N.
1878
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001880 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 help
1882 Usually, you have to use modules compiled with your kernel.
1883 Saying Y here makes it sometimes possible to use modules
1884 compiled for different kernels, by adding enough information
1885 to the modules to (hopefully) spot any changes which would
1886 make them incompatible with the kernel you are running. If
1887 unsure, say N.
1888
1889config MODULE_SRCVERSION_ALL
1890 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 help
1892 Modules which contain a MODULE_VERSION get an extra "srcversion"
1893 field inserted into their modinfo section, which contains a
1894 sum of the source files which made it. This helps maintainers
1895 see exactly which source was used to build a module (since
1896 others sometimes change the module source without updating
1897 the version). With this option, such a "srcversion" field
1898 will be created for all modules. If unsure, say N.
1899
Rusty Russell106a4ee2012-09-26 10:09:40 +01001900config MODULE_SIG
1901 bool "Module signature verification"
1902 depends on MODULES
David Howells091f6e22015-07-20 21:16:28 +01001903 select SYSTEM_DATA_VERIFICATION
Rusty Russell106a4ee2012-09-26 10:09:40 +01001904 help
1905 Check modules for valid signatures upon load: the signature
1906 is simply appended to the module. For more information see
1907 Documentation/module-signing.txt.
1908
David Howells228c37f2015-08-11 12:38:54 +01001909 Note that this option adds the OpenSSL development packages as a
1910 kernel build dependency so that the signing tool can use its crypto
1911 library.
1912
David Howellsea0b6dc2012-09-26 10:09:50 +01001913 !!!WARNING!!! If you enable this option, you MUST make sure that the
1914 module DOES NOT get stripped after being signed. This includes the
1915 debuginfo strip done by some packagers (such as rpmbuild) and
1916 inclusion into an initramfs that wants the module size reduced.
1917
Rusty Russell106a4ee2012-09-26 10:09:40 +01001918config MODULE_SIG_FORCE
1919 bool "Require modules to be validly signed"
1920 depends on MODULE_SIG
1921 help
1922 Reject unsigned modules or signed modules for which we don't have a
1923 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001924
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301925config MODULE_SIG_ALL
1926 bool "Automatically sign all modules"
1927 default y
1928 depends on MODULE_SIG
1929 help
1930 Sign all modules during make modules_install. Without this option,
1931 modules must be signed manually, using the scripts/sign-file tool.
1932
1933comment "Do not forget to sign required modules with scripts/sign-file"
1934 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1935
David Howellsea0b6dc2012-09-26 10:09:50 +01001936choice
1937 prompt "Which hash algorithm should modules be signed with?"
1938 depends on MODULE_SIG
1939 help
1940 This determines which sort of hashing algorithm will be used during
1941 signature generation. This algorithm _must_ be built into the kernel
1942 directly so that signature verification can take place. It is not
1943 possible to load a signed module containing the algorithm to check
1944 the signature on that module.
1945
1946config MODULE_SIG_SHA1
1947 bool "Sign modules with SHA-1"
1948 select CRYPTO_SHA1
1949
1950config MODULE_SIG_SHA224
1951 bool "Sign modules with SHA-224"
1952 select CRYPTO_SHA256
1953
1954config MODULE_SIG_SHA256
1955 bool "Sign modules with SHA-256"
1956 select CRYPTO_SHA256
1957
1958config MODULE_SIG_SHA384
1959 bool "Sign modules with SHA-384"
1960 select CRYPTO_SHA512
1961
1962config MODULE_SIG_SHA512
1963 bool "Sign modules with SHA-512"
1964 select CRYPTO_SHA512
1965
1966endchoice
1967
Michal Marek22753672013-01-25 13:41:00 +10301968config MODULE_SIG_HASH
1969 string
1970 depends on MODULE_SIG
1971 default "sha1" if MODULE_SIG_SHA1
1972 default "sha224" if MODULE_SIG_SHA224
1973 default "sha256" if MODULE_SIG_SHA256
1974 default "sha384" if MODULE_SIG_SHA384
1975 default "sha512" if MODULE_SIG_SHA512
1976
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301977config MODULE_COMPRESS
1978 bool "Compress modules on installation"
1979 depends on MODULES
1980 help
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301981
Rusty Russellb6c09b52015-06-16 12:16:22 +09301982 Compresses kernel modules when 'make modules_install' is run; gzip or
1983 xz depending on "Compression algorithm" below.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301984
Rusty Russellb6c09b52015-06-16 12:16:22 +09301985 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301986
Rusty Russellb6c09b52015-06-16 12:16:22 +09301987 Out-of-tree kernel modules installed using Kbuild will also be
1988 compressed upon installation.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301989
Rusty Russellb6c09b52015-06-16 12:16:22 +09301990 Note: for modules inside an initrd or initramfs, it's more efficient
1991 to compress the whole initrd or initramfs instead.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301992
Rusty Russellb6c09b52015-06-16 12:16:22 +09301993 Note: This is fully compatible with signed modules.
1994
1995 If in doubt, say N.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301996
1997choice
1998 prompt "Compression algorithm"
1999 depends on MODULE_COMPRESS
2000 default MODULE_COMPRESS_GZIP
2001 help
2002 This determines which sort of compression will be used during
2003 'make modules_install'.
2004
2005 GZIP (default) and XZ are supported.
2006
2007config MODULE_COMPRESS_GZIP
2008 bool "GZIP"
2009
2010config MODULE_COMPRESS_XZ
2011 bool "XZ"
2012
2013endchoice
2014
Robert P. J. Day0b0de142008-08-04 13:31:32 -04002015endif # MODULES
2016
Peter Zijlstra6c9692e2015-05-27 11:09:37 +09302017config MODULES_TREE_LOOKUP
2018 def_bool y
2019 depends on PERF_EVENTS || TRACING
2020
Rusty Russell98a79d62008-12-13 21:19:41 +10302021config INIT_ALL_POSSIBLE
2022 bool
2023 help
Rusty Russell5f054e32012-03-29 15:38:31 +10302024 Back when each arch used to define their own cpu_online_mask and
2025 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10302026 with all 1s, and others with all 0s. When they were centralised,
2027 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01002028 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10302029
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002030source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07002031
2032config PREEMPT_NOTIFIERS
2033 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01002034
Steffen Klassert16295be2010-01-06 19:47:10 +11002035config PADATA
2036 depends on SMP
2037 bool
2038
Andi Kleen754b7b62012-10-04 17:11:27 -07002039# Can be selected by architectures with broken toolchains
2040# that get confused by correct const<->read_only section
2041# mappings
2042config BROKEN_RODATA
2043 bool
2044
David Howells4520c6a2012-09-21 23:31:13 +01002045config ASN1
2046 tristate
2047 help
2048 Build a simple ASN.1 grammar compiler that produces a bytecode output
2049 that can be interpreted by the ASN.1 stream decoder and used to
2050 inform it as to what tags are to be expected in a stream and what
2051 functions to call on what tags.
2052
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002053source "kernel/Kconfig.locks"