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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"
288 default y
289 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
302 logging of avc messages output). Does not do system-call
303 auditing without CONFIG_AUDITSYSCALL.
304
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900305config HAVE_ARCH_AUDITSYSCALL
306 bool
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308config AUDITSYSCALL
309 bool "Enable system-call auditing support"
AKASHI Takahiro7a017722014-02-25 18:16:24 +0900310 depends on AUDIT && HAVE_ARCH_AUDITSYSCALL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 default y if SECURITY_SELINUX
312 help
313 Enable low-overhead system-call auditing infrastructure that
314 can be used independently or with another kernel subsystem,
Eric Paris67640b62009-12-17 20:12:06 -0500315 such as SELinux.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Eric Paris939a67f2009-12-17 20:12:06 -0500317config AUDIT_WATCH
318 def_bool y
319 depends on AUDITSYSCALL
320 select FSNOTIFY
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Al Viro74c3cbe2007-07-22 08:04:18 -0400322config AUDIT_TREE
323 def_bool y
Eric Paris63c882a2009-05-21 17:02:01 -0400324 depends on AUDITSYSCALL
Eric Paris28a3a7e2009-12-17 20:12:05 -0500325 select FSNOTIFY
Al Viro74c3cbe2007-07-22 08:04:18 -0400326
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000327source "kernel/irq/Kconfig"
Thomas Gleixner764e0da2012-05-21 23:16:18 +0200328source "kernel/time/Kconfig"
Thomas Gleixnerd9817eb2010-09-27 12:45:59 +0000329
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200330menu "CPU/Task time and stats accounting"
331
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200332config VIRT_CPU_ACCOUNTING
333 bool
334
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200335choice
336 prompt "Cputime accounting"
337 default TICK_CPU_ACCOUNTING if !PPC64
Stephen Rothwell02fc8d32013-02-08 14:19:38 +1100338 default VIRT_CPU_ACCOUNTING_NATIVE if PPC64
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200339
340# Kind of a stub config for the pure tick based cputime accounting
341config TICK_CPU_ACCOUNTING
342 bool "Simple tick based cputime accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200343 depends on !S390 && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200344 help
345 This is the basic tick based cputime accounting that maintains
346 statistics about user, system and idle time spent on per jiffies
347 granularity.
348
349 If unsure, say Y.
350
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200351config VIRT_CPU_ACCOUNTING_NATIVE
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200352 bool "Deterministic task and CPU time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200353 depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200354 select VIRT_CPU_ACCOUNTING
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200355 help
356 Select this option to enable more accurate task and CPU time
357 accounting. This is done by reading a CPU counter on each
358 kernel entry and exit and on transitions within the kernel
359 between system, softirq and hardirq state, so there is a
360 small performance impact. In the case of s390 or IBM POWER > 5,
361 this also enables accounting of stolen time on logically-partitioned
362 systems.
363
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200364config VIRT_CPU_ACCOUNTING_GEN
365 bool "Full dynticks CPU time accounting"
Kevin Hilmanff3fb252013-09-16 15:28:19 -0700366 depends on HAVE_CONTEXT_TRACKING
Kevin Hilman554b0002013-09-16 15:28:21 -0700367 depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
Frederic Weisbeckerabf917c2012-07-25 07:56:04 +0200368 select VIRT_CPU_ACCOUNTING
369 select CONTEXT_TRACKING
370 help
371 Select this option to enable task and CPU time accounting on full
372 dynticks systems. This accounting is implemented by watching every
373 kernel-user boundaries using the context tracking subsystem.
374 The accounting is thus performed at the expense of some significant
375 overhead.
376
377 For now this is only useful if you are working on the full
378 dynticks subsystem development.
379
380 If unsure, say N.
381
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200382config IRQ_TIME_ACCOUNTING
383 bool "Fine granularity task level IRQ time accounting"
Frederic Weisbeckerc58b0df2013-04-26 15:16:31 +0200384 depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200385 help
386 Select this option to enable fine granularity task irq time
387 accounting. This is done by reading a timestamp on each
388 transitions between softirq and hardirq state, so there can be a
389 small performance impact.
390
391 If in doubt, say N here.
392
393endchoice
394
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200395config BSD_PROCESS_ACCT
396 bool "BSD Process Accounting"
Iulia Manda28138932015-04-15 16:16:41 -0700397 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200398 help
399 If you say Y here, a user level program will be able to instruct the
400 kernel (via a special system call) to write process accounting
401 information to a file: whenever a process exits, information about
402 that process will be appended to the file by the kernel. The
403 information includes things such as creation time, owning user,
404 command name, memory usage, controlling terminal etc. (the complete
405 list is in the struct acct in <file:include/linux/acct.h>). It is
406 up to the user level program to do useful things with this
407 information. This is generally a good idea, so say Y.
408
409config BSD_PROCESS_ACCT_V3
410 bool "BSD Process Accounting version 3 file format"
411 depends on BSD_PROCESS_ACCT
412 default n
413 help
414 If you say Y here, the process accounting information is written
415 in a new file format that also logs the process IDs of each
416 process and it's parent. Note that this file format is incompatible
417 with previous v0/v1/v2 file formats, so you will need updated tools
418 for processing it. A preliminary version of these tools is available
419 at <http://www.gnu.org/software/acct/>.
420
421config TASKSTATS
Kees Cook19c92392012-10-02 11:19:29 -0700422 bool "Export task/process statistics through netlink"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200423 depends on NET
Iulia Manda28138932015-04-15 16:16:41 -0700424 depends on MULTIUSER
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200425 default n
426 help
427 Export selected statistics for tasks/processes through the
428 generic netlink interface. Unlike BSD process accounting, the
429 statistics are available during the lifetime of tasks/processes as
430 responses to commands. Like BSD accounting, they are sent to user
431 space on task exit.
432
433 Say N if unsure.
434
435config TASK_DELAY_ACCT
Kees Cook19c92392012-10-02 11:19:29 -0700436 bool "Enable per-task delay accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200437 depends on TASKSTATS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530438 select SCHED_INFO
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200439 help
440 Collect information on time spent by a task waiting for system
441 resources like cpu, synchronous block I/O completion and swapping
442 in pages. Such statistics can help in setting a task's priorities
443 relative to other tasks for cpu, io, rss limits etc.
444
445 Say N if unsure.
446
447config TASK_XACCT
Kees Cook19c92392012-10-02 11:19:29 -0700448 bool "Enable extended accounting over taskstats"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200449 depends on TASKSTATS
450 help
451 Collect extended task accounting data and send the data
452 to userland for processing over the taskstats interface.
453
454 Say N if unsure.
455
456config TASK_IO_ACCOUNTING
Kees Cook19c92392012-10-02 11:19:29 -0700457 bool "Enable per-task storage I/O accounting"
Frederic Weisbecker391dc692012-09-09 14:22:07 +0200458 depends on TASK_XACCT
459 help
460 Collect information on the number of bytes of storage I/O which this
461 task has caused.
462
463 Say N if unsure.
464
465endmenu # "CPU/Task time and stats accounting"
466
Mike Travisc903ff82009-01-15 12:28:29 -0800467menu "RCU Subsystem"
468
Mike Travisc903ff82009-01-15 12:28:29 -0800469config TREE_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400470 bool
471 default y if !PREEMPT && SMP
Mike Travisc903ff82009-01-15 12:28:29 -0800472 help
473 This option selects the RCU implementation that is
474 designed for very large SMP system with hundreds or
Paul E. McKenneyc17ef452009-06-23 17:12:47 -0700475 thousands of CPUs. It also scales down nicely to
476 smaller systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800477
Pranith Kumar28f65692014-09-22 14:00:48 -0400478config PREEMPT_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400479 bool
480 default y if PREEMPT
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700481 help
482 This option selects the RCU implementation that is
483 designed for very large SMP systems with hundreds or
484 thousands of CPUs, but for which real-time response
Paul E. McKenneybbe3eae2009-09-13 09:15:08 -0700485 is also required. It also scales down nicely to
486 smaller systems.
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700487
Paul E. McKenney9fc52d82013-01-08 15:48:33 -0800488 Select this option if you are unsure.
489
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700490config TINY_RCU
Pranith Kumare72aeaf2015-04-21 17:29:42 -0400491 bool
492 default y if !PREEMPT && !SMP
Paul E. McKenney9b1d82f2009-10-25 19:03:50 -0700493 help
494 This option selects the RCU implementation that is
495 designed for UP systems from which real-time response
496 is not required. This option greatly reduces the
497 memory footprint of RCU.
498
Paul E. McKenney78cae102015-04-20 12:19:45 -0700499config RCU_EXPERT
500 bool "Make expert-level adjustments to RCU configuration"
501 default n
502 help
503 This option needs to be enabled if you wish to make
504 expert-level adjustments to RCU configuration. By default,
505 no such adjustments can be made, which has the often-beneficial
506 side-effect of preventing "make oldconfig" from asking you all
507 sorts of detailed questions about how you would like numerous
508 obscure RCU options to be set up.
509
510 Say Y if you need to make expert-level adjustments to RCU.
511
512 Say N if you are unsure.
513
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500514config SRCU
515 bool
516 help
517 This option selects the sleepable version of RCU. This version
518 permits arbitrary sleeping or blocking within RCU read-side critical
519 sections.
520
Paul E. McKenney8315f422014-06-27 13:42:20 -0700521config TASKS_RCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -0700522 bool
Paul E. McKenney8315f422014-06-27 13:42:20 -0700523 default n
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500524 select SRCU
Paul E. McKenney8315f422014-06-27 13:42:20 -0700525 help
526 This option enables a task-based RCU implementation that uses
527 only voluntary context switch (not preemption!), idle, and
528 user-mode execution as quiescent states.
529
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700530config RCU_STALL_COMMON
Pranith Kumar28f65692014-09-22 14:00:48 -0400531 def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700532 help
533 This option enables RCU CPU stall code that is common between
534 the TINY and TREE variants of RCU. The purpose is to allow
535 the tiny variants to disable RCU CPU stall warnings, while
536 making these warnings mandatory for the tree variants.
537
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100538config CONTEXT_TRACKING
539 bool
540
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100541config CONTEXT_TRACKING_FORCE
542 bool "Force context tracking"
543 depends on CONTEXT_TRACKING
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200544 default y if !NO_HZ_FULL
Frederic Weisbecker1fd2b442012-07-11 20:26:40 +0200545 help
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200546 The major pre-requirement for full dynticks to work is to
547 support the context tracking subsystem. But there are also
548 other dependencies to provide in order to make the full
549 dynticks working.
550
551 This option stands for testing when an arch implements the
552 context tracking backend but doesn't yet fullfill all the
553 requirements to make the full dynticks feature working.
554 Without the full dynticks, there is no way to test the support
555 for context tracking and the subsystems that rely on it: RCU
556 userspace extended quiescent state and tickless cputime
557 accounting. This option copes with the absence of the full
558 dynticks subsystem by forcing the context tracking on all
559 CPUs in the system.
560
Paul Gortmaker99c8b1e2013-10-24 10:07:47 -0400561 Say Y only if you're working on the development of an
Frederic Weisbeckerd84d27a2013-07-24 21:59:29 +0200562 architecture backend for the context tracking.
563
564 Say N otherwise, this option brings an overhead that you
565 don't want in production.
566
Frederic Weisbeckerd6771242012-10-11 01:48:28 +0200567
Mike Travisc903ff82009-01-15 12:28:29 -0800568config RCU_FANOUT
569 int "Tree-based hierarchical RCU fanout value"
570 range 2 64 if 64BIT
571 range 2 32 if !64BIT
Paul E. McKenney05c5df32015-04-20 14:27:43 -0700572 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Mike Travisc903ff82009-01-15 12:28:29 -0800573 default 64 if 64BIT
574 default 32 if !64BIT
575 help
576 This option controls the fanout of hierarchical implementations
577 of RCU, allowing RCU to work efficiently on machines with
Paul E. McKenney4d87ffa2010-08-04 17:31:12 -0700578 large numbers of CPUs. This value must be at least the fourth
579 root of NR_CPUS, which allows NR_CPUS to be insanely large.
580 The default value of RCU_FANOUT should be used for production
581 systems, but if you are stress-testing the RCU implementation
582 itself, small RCU_FANOUT values allow you to test large-system
583 code paths on small(er) systems.
Mike Travisc903ff82009-01-15 12:28:29 -0800584
585 Select a specific number if testing RCU itself.
586 Take the default if unsure.
587
Paul E. McKenney8932a632012-04-19 12:20:14 -0700588config RCU_FANOUT_LEAF
589 int "Tree-based hierarchical RCU leaf-level fanout value"
Paul E. McKenney8739c5c2015-04-20 18:27:54 -0700590 range 2 64 if 64BIT
591 range 2 32 if !64BIT
Paul E. McKenney47d631a2015-04-21 09:12:13 -0700592 depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
Paul E. McKenney8932a632012-04-19 12:20:14 -0700593 default 16
594 help
595 This option controls the leaf-level fanout of hierarchical
596 implementations of RCU, and allows trading off cache misses
597 against lock contention. Systems that synchronize their
598 scheduling-clock interrupts for energy-efficiency reasons will
599 want the default because the smaller leaf-level fanout keeps
600 lock contention levels acceptably low. Very large systems
601 (hundreds or thousands of CPUs) will instead want to set this
602 value to the maximum value possible in order to reduce the
603 number of cache misses incurred during RCU's grace-period
604 initialization. These systems tend to run CPU-bound, and thus
605 are not helped by synchronized interrupts, and thus tend to
606 skew them, which reduces lock contention enough that large
607 leaf-level fanouts work well.
608
609 Select a specific number if testing RCU itself.
610
611 Select the maximum permissible value for large systems.
612
613 Take the default if unsure.
614
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800615config RCU_FAST_NO_HZ
616 bool "Accelerate last non-dyntick-idle CPU's grace periods"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700617 depends on NO_HZ_COMMON && SMP && RCU_EXPERT
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800618 default n
619 help
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800620 This option permits CPUs to enter dynticks-idle state even if
621 they have RCU callbacks queued, and prevents RCU from waking
622 these CPUs up more than roughly once every four jiffies (by
623 default, you can adjust this using the rcutree.rcu_idle_gp_delay
624 parameter), thus improving energy efficiency. On the other
625 hand, this option increases the duration of RCU grace periods,
626 for example, slowing down synchronize_rcu().
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800627
Paul E. McKenneyc0f4dfd2012-12-28 11:30:36 -0800628 Say Y if energy efficiency is critically important, and you
629 don't care about increased grace-period durations.
Paul E. McKenney8bd93a22010-02-22 17:04:59 -0800630
631 Say N if you are unsure.
632
Mike Travisc903ff82009-01-15 12:28:29 -0800633config TREE_RCU_TRACE
Pranith Kumar28f65692014-09-22 14:00:48 -0400634 def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
Mike Travisc903ff82009-01-15 12:28:29 -0800635 select DEBUG_FS
636 help
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700637 This option provides tracing for the TREE_RCU and
Pranith Kumar28f65692014-09-22 14:00:48 -0400638 PREEMPT_RCU implementations, permitting Makefile to
Paul E. McKenneyf41d9112009-08-22 13:56:52 -0700639 trivially select kernel/rcutree_trace.c.
Mike Travisc903ff82009-01-15 12:28:29 -0800640
Paul E. McKenney24278d12010-09-27 17:25:23 -0700641config RCU_BOOST
642 bool "Enable RCU priority boosting"
Paul E. McKenney78cae102015-04-20 12:19:45 -0700643 depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700644 default n
645 help
646 This option boosts the priority of preempted RCU readers that
647 block the current preemptible RCU grace period for too long.
648 This option also prevents heavy loads from blocking RCU
649 callback invocation for all flavors of RCU.
650
651 Say Y here if you are working with real-time apps or heavy loads
652 Say N here if you are unsure.
653
Clark Williams21871d72014-09-12 21:21:09 -0500654config RCU_KTHREAD_PRIO
655 int "Real-time priority to use for RCU worker threads"
Paul E. McKenneya94844b2014-12-12 07:37:48 -0800656 range 1 99 if RCU_BOOST
657 range 0 99 if !RCU_BOOST
658 default 1 if RCU_BOOST
659 default 0 if !RCU_BOOST
Paul E. McKenney26730f52015-04-21 09:22:14 -0700660 depends on RCU_EXPERT
Paul E. McKenney24278d12010-09-27 17:25:23 -0700661 help
Clark Williams21871d72014-09-12 21:21:09 -0500662 This option specifies the SCHED_FIFO priority value that will be
663 assigned to the rcuc/n and rcub/n threads and is also the value
664 used for RCU_BOOST (if enabled). If you are working with a
665 real-time application that has one or more CPU-bound threads
666 running at a real-time priority level, you should set
667 RCU_KTHREAD_PRIO to a priority higher than the highest-priority
668 real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
669 value of 1 is appropriate in the common case, which is real-time
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700670 applications that do not have any CPU-bound threads.
671
672 Some real-time applications might not have a single real-time
673 thread that saturates a given CPU, but instead might have
674 multiple real-time threads that, taken together, fully utilize
Clark Williams21871d72014-09-12 21:21:09 -0500675 that CPU. In this case, you should set RCU_KTHREAD_PRIO to
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700676 a priority higher than the lowest-priority thread that is
677 conspiring to prevent the CPU from running any non-real-time
678 tasks. For example, if one thread at priority 10 and another
679 thread at priority 5 are between themselves fully consuming
Clark Williams21871d72014-09-12 21:21:09 -0500680 the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
Paul E. McKenneyc9336642012-04-18 16:20:18 -0700681 set to priority 6 or higher.
Paul E. McKenney24278d12010-09-27 17:25:23 -0700682
683 Specify the real-time priority, or take the default if unsure.
684
685config RCU_BOOST_DELAY
686 int "Milliseconds to delay boosting after RCU grace-period start"
687 range 0 3000
688 depends on RCU_BOOST
689 default 500
690 help
691 This option specifies the time to wait after the beginning of
692 a given grace period before priority-boosting preempted RCU
693 readers blocking that grace period. Note that any RCU reader
694 blocking an expedited RCU grace period is boosted immediately.
695
696 Accept the default if unsure.
697
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700698config RCU_NOCB_CPU
Paul E. McKenney9a5739d2013-03-28 20:48:36 -0700699 bool "Offload RCU callback processing from boot-selected CPUs"
Pranith Kumar28f65692014-09-22 14:00:48 -0400700 depends on TREE_RCU || PREEMPT_RCU
Paul E. McKenneybe55fa22015-06-02 05:29:18 -0700701 depends on RCU_EXPERT || NO_HZ_FULL
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700702 default n
703 help
704 Use this option to reduce OS jitter for aggressive HPC or
705 real-time workloads. It can also be used to offload RCU
706 callback invocation to energy-efficient CPUs in battery-powered
707 asymmetric multiprocessors.
708
709 This option offloads callback invocation from the set of
710 CPUs specified at boot time by the rcu_nocbs parameter.
Paul E. McKenneya4889852012-12-03 08:16:28 -0800711 For each such CPU, a kthread ("rcuox/N") will be created to
712 invoke callbacks, where the "N" is the CPU being offloaded,
713 and where the "x" is "b" for RCU-bh, "p" for RCU-preempt, and
714 "s" for RCU-sched. Nothing prevents this kthread from running
715 on the specified CPUs, but (1) the kthreads may be preempted
716 between each callback, and (2) affinity or cgroups can be used
717 to force the kthreads to run on whatever set of CPUs is desired.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700718
Paul E. McKenney34ed62462013-01-07 13:37:42 -0800719 Say Y here if you want to help to debug reduced OS jitter.
Paul E. McKenney3fbfbf72012-08-19 21:35:53 -0700720 Say N here if you are unsure.
721
Paul E. McKenney911af502013-02-11 10:23:27 -0800722choice
723 prompt "Build-forced no-CBs CPUs"
724 default RCU_NOCB_CPU_NONE
Stefan Hengelein45687792014-09-02 19:55:11 +0200725 depends on RCU_NOCB_CPU
Paul E. McKenney911af502013-02-11 10:23:27 -0800726 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700727 This option allows no-CBs CPUs (whose RCU callbacks are invoked
728 from kthreads rather than from softirq context) to be specified
729 at build time. Additional no-CBs CPUs may be specified by
730 the rcu_nocbs= boot parameter.
Paul E. McKenney911af502013-02-11 10:23:27 -0800731
732config RCU_NOCB_CPU_NONE
733 bool "No build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800734 help
735 This option does not force any of the CPUs to be no-CBs CPUs.
736 Only CPUs designated by the rcu_nocbs= boot parameter will be
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700737 no-CBs CPUs, whose RCU callbacks will be invoked by per-CPU
738 kthreads whose names begin with "rcuo". All other CPUs will
739 invoke their own RCU callbacks in softirq context.
740
741 Select this option if you want to choose no-CBs CPUs at
742 boot time, for example, to allow testing of different no-CBs
743 configurations without having to rebuild the kernel each time.
Paul E. McKenney911af502013-02-11 10:23:27 -0800744
745config RCU_NOCB_CPU_ZERO
746 bool "CPU 0 is a build_forced no-CBs CPU"
Paul E. McKenney911af502013-02-11 10:23:27 -0800747 help
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700748 This option forces CPU 0 to be a no-CBs CPU, so that its RCU
749 callbacks are invoked by a per-CPU kthread whose name begins
750 with "rcuo". Additional CPUs may be designated as no-CBs
751 CPUs using the rcu_nocbs= boot parameter will be no-CBs CPUs.
752 All other CPUs will invoke their own RCU callbacks in softirq
753 context.
Paul E. McKenney911af502013-02-11 10:23:27 -0800754
755 Select this if CPU 0 needs to be a no-CBs CPU for real-time
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700756 or energy-efficiency reasons, but the real reason it exists
757 is to ensure that randconfig testing covers mixed systems.
Paul E. McKenney911af502013-02-11 10:23:27 -0800758
759config RCU_NOCB_CPU_ALL
760 bool "All CPUs are build_forced no-CBs CPUs"
Paul E. McKenney911af502013-02-11 10:23:27 -0800761 help
762 This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
Paul E. McKenney676c3dc2013-04-30 14:49:42 -0700763 boot parameter will be ignored. All CPUs' RCU callbacks will
764 be executed in the context of per-CPU rcuo kthreads created for
765 this purpose. Assuming that the kthreads whose names start with
766 "rcuo" are bound to "housekeeping" CPUs, this reduces OS jitter
767 on the remaining CPUs, but might decrease memory locality during
768 RCU-callback invocation, thus potentially degrading throughput.
Paul E. McKenney911af502013-02-11 10:23:27 -0800769
770 Select this if all CPUs need to be no-CBs CPUs for real-time
771 or energy-efficiency reasons.
772
773endchoice
774
Paul E. McKenneyee425712015-02-19 10:51:32 -0800775config RCU_EXPEDITE_BOOT
776 bool
777 default n
778 help
779 This option enables expedited grace periods at boot time,
780 as if rcu_expedite_gp() had been invoked early in boot.
781 The corresponding rcu_unexpedite_gp() is invoked from
782 rcu_end_inkernel_boot(), which is intended to be invoked
783 at the end of the kernel-only boot sequence, just before
784 init is exec'ed.
785
786 Accept the default if unsure.
787
Mike Travisc903ff82009-01-15 12:28:29 -0800788endmenu # "RCU Subsystem"
789
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700790config BUILD_BIN2C
791 bool
792 default n
793
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794config IKCONFIG
Ross Birof2443ab2006-09-30 23:27:25 -0700795 tristate "Kernel .config support"
Vivek Goyalde5b56b2014-08-08 14:25:41 -0700796 select BUILD_BIN2C
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 ---help---
798 This option enables the complete Linux kernel ".config" file
799 contents to be saved in the kernel. It provides documentation
800 of which kernel options are used in a running kernel or in an
801 on-disk kernel. This information can be extracted from the kernel
802 image file with the script scripts/extract-ikconfig and used as
803 input to rebuild the current kernel or to build another kernel.
804 It can also be extracted from a running kernel by reading
805 /proc/config.gz if enabled (below).
806
807config IKCONFIG_PROC
808 bool "Enable access to .config through /proc/config.gz"
809 depends on IKCONFIG && PROC_FS
810 ---help---
811 This option enables access to the kernel configuration file
812 through /proc/config.gz.
813
Alistair John Strachan794543a2007-05-08 00:31:15 -0700814config LOG_BUF_SHIFT
815 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
Ingo Molnarfb39f982015-07-01 10:19:11 +0200816 range 12 25
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700817 default 17
Josh Triplett361e9df2014-10-03 16:00:54 -0700818 depends on PRINTK
Alistair John Strachan794543a2007-05-08 00:31:15 -0700819 help
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700820 Select the minimal kernel log buffer size as a power of 2.
821 The final size is affected by LOG_CPU_MAX_BUF_SHIFT config
822 parameter, see below. Any higher size also might be forced
823 by "log_buf_len" boot parameter.
824
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700825 Examples:
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700826 17 => 128 KB
Adrian Bunkf17a32e2008-04-29 00:58:58 -0700827 16 => 64 KB
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700828 15 => 32 KB
829 14 => 16 KB
Alistair John Strachan794543a2007-05-08 00:31:15 -0700830 13 => 8 KB
831 12 => 4 KB
832
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700833config LOG_CPU_MAX_BUF_SHIFT
834 int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)"
Geert Uytterhoeven2240a312014-10-13 15:51:11 -0700835 depends on SMP
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700836 range 0 21
837 default 12 if !BASE_SMALL
838 default 0 if BASE_SMALL
Josh Triplett361e9df2014-10-03 16:00:54 -0700839 depends on PRINTK
Luis R. Rodriguez23b28992014-08-06 16:08:56 -0700840 help
841 This option allows to increase the default ring buffer size
842 according to the number of CPUs. The value defines the contribution
843 of each CPU as a power of 2. The used space is typically only few
844 lines however it might be much more when problems are reported,
845 e.g. backtraces.
846
847 The increased size means that a new buffer has to be allocated and
848 the original static one is unused. It makes sense only on systems
849 with more CPUs. Therefore this value is used only when the sum of
850 contributions is greater than the half of the default kernel ring
851 buffer as defined by LOG_BUF_SHIFT. The default values are set
852 so that more than 64 CPUs are needed to trigger the allocation.
853
854 Also this option is ignored when "log_buf_len" kernel parameter is
855 used as it forces an exact (power of two) size of the ring buffer.
856
857 The number of possible CPUs is used for this computation ignoring
858 hotplugging making the compuation optimal for the the worst case
859 scenerio while allowing a simple algorithm to be used from bootup.
860
861 Examples shift values and their meaning:
862 17 => 128 KB for each CPU
863 16 => 64 KB for each CPU
864 15 => 32 KB for each CPU
865 14 => 16 KB for each CPU
866 13 => 8 KB for each CPU
867 12 => 4 KB for each CPU
868
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800869#
870# Architectures with an unreliable sched_clock() should select this:
871#
872config HAVE_UNSTABLE_SCHED_CLOCK
873 bool
874
Stephen Boyd38ff87f2013-06-01 23:39:40 -0700875config GENERIC_SCHED_CLOCK
876 bool
877
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200878#
879# For architectures that want to enable the support for NUMA-affine scheduler
880# balancing logic:
881#
882config ARCH_SUPPORTS_NUMA_BALANCING
883 bool
884
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100885#
Mel Gorman72b252a2015-09-04 15:47:32 -0700886# For architectures that prefer to flush all TLBs after a number of pages
887# are unmapped instead of sending one IPI per page to flush. The architecture
888# must provide guarantees on what happens if a clean TLB cache entry is
889# written after the unmap. Details are in mm/rmap.c near the check for
890# should_defer_flush. The architecture should also consider if the full flush
891# and the refill costs are offset by the savings of sending fewer IPIs.
892config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
893 bool
894
895#
Peter Zijlstrabe5e6102013-11-18 18:27:06 +0100896# For architectures that know their GCC __int128 support is sound
897#
898config ARCH_SUPPORTS_INT128
899 bool
900
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200901# For architectures that (ab)use NUMA to represent different memory regions
902# all cpu-local but of different latencies, such as SuperH.
903#
904config ARCH_WANT_NUMA_VARIABLE_LOCALITY
905 bool
906
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200907config NUMA_BALANCING
908 bool "Memory placement aware NUMA scheduler"
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200909 depends on ARCH_SUPPORTS_NUMA_BALANCING
910 depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
911 depends on SMP && NUMA && MIGRATION
912 help
913 This option adds support for automatic NUMA aware memory/task placement.
914 The mechanism is quite primitive and is based on migrating memory when
Paul Gortmaker6d56a412013-08-13 11:06:50 -0400915 it has references to the node the task is running on.
Andrea Arcangelibe3a7282012-10-04 01:50:47 +0200916
917 This system will be inactive on UMA systems.
918
Aneesh Kumar K.V6f7c97e2014-12-10 15:43:37 -0800919config NUMA_BALANCING_DEFAULT_ENABLED
920 bool "Automatically enable NUMA aware memory/task placement"
921 default y
922 depends on NUMA_BALANCING
923 help
924 If set, automatic NUMA balancing will be enabled if running on a NUMA
925 machine.
926
Li Zefan23964d22009-01-15 13:50:58 -0800927menuconfig CGROUPS
Christoph Jaeger6341e622014-12-20 15:41:11 -0500928 bool "Control Group support"
Tejun Heo2bd59d42014-02-11 11:52:49 -0500929 select KERNFS
Paul Menageddbcc7e2007-10-18 23:39:30 -0700930 help
Li Zefan23964d22009-01-15 13:50:58 -0800931 This option adds support for grouping sets of processes together, for
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800932 use with process control subsystems such as Cpusets, CFS, memory
933 controls or device isolation.
934 See
KAMEZAWA Hiroyuki5cdc38f2009-01-07 18:07:30 -0800935 - Documentation/scheduler/sched-design-CFS.txt (CFS)
Li Zefan45ce80f2009-01-15 13:50:59 -0800936 - Documentation/cgroups/ (features for grouping, isolation
937 and resource control)
Paul Menageddbcc7e2007-10-18 23:39:30 -0700938
939 Say N if unsure.
940
Li Zefan23964d22009-01-15 13:50:58 -0800941if CGROUPS
942
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800943config PAGE_COUNTER
944 bool
945
Andrew Mortonc255a452012-07-31 16:43:02 -0700946config MEMCG
Johannes Weinera0166ec2015-12-17 17:19:56 -0500947 bool "Memory controller"
Johannes Weiner3e32cb22014-12-10 15:42:31 -0800948 select PAGE_COUNTER
Tejun Heo79bd9812013-11-22 18:20:42 -0500949 select EVENTFD
Balbir Singh00f0b822008-03-04 14:28:39 -0800950 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500951 Provides control over the memory footprint of tasks in a cgroup.
Balbir Singh00f0b822008-03-04 14:28:39 -0800952
Andrew Mortonc255a452012-07-31 16:43:02 -0700953config MEMCG_SWAP
Johannes Weinera0166ec2015-12-17 17:19:56 -0500954 bool "Swap controller"
Andrew Mortonc255a452012-07-31 16:43:02 -0700955 depends on MEMCG && SWAP
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800956 help
Johannes Weinera0166ec2015-12-17 17:19:56 -0500957 Provides control over the swap space consumed by tasks in a cgroup.
958
Andrew Mortonc255a452012-07-31 16:43:02 -0700959config MEMCG_SWAP_ENABLED
Johannes Weinera0166ec2015-12-17 17:19:56 -0500960 bool "Swap controller enabled by default"
Andrew Mortonc255a452012-07-31 16:43:02 -0700961 depends on MEMCG_SWAP
Michal Hockoa42c3902010-11-24 12:57:08 -0800962 default y
963 help
964 Memory Resource Controller Swap Extension comes with its price in
965 a bigger memory consumption. General purpose distribution kernels
Jim Cromie43d547f2010-12-17 14:32:36 -0700966 which want to enable the feature but keep it disabled by default
Michal Hocko07555ac2013-08-22 16:35:46 -0700967 and let the user enable it by swapaccount=1 boot command line
Michal Hockoa42c3902010-11-24 12:57:08 -0800968 parameter should have this option unselected.
969 For those who want to have the feature enabled by default should
970 select this option (if, for some reason, they need to disable it
WANG Cong00a66d22011-07-25 17:12:12 -0700971 then swapaccount=0 does the trick).
Andrew Mortonc255a452012-07-31 16:43:02 -0700972config MEMCG_KMEM
Kees Cook19c92392012-10-02 11:19:29 -0700973 bool "Memory Resource Controller Kernel Memory accounting"
974 depends on MEMCG
Glauber Costa510fc4e2012-12-18 14:21:47 -0800975 depends on SLUB || SLAB
Glauber Costae5671df2011-12-11 21:47:01 +0000976 help
977 The Kernel Memory extension for Memory Resource Controller can limit
978 the amount of memory used by kernel objects in the system. Those are
979 fundamentally different from the entities handled by the standard
980 Memory Controller, which are page-based, and can be swapped. Users of
981 the kmem extension can use it to guarantee that no group of processes
982 will ever exhaust kernel resources alone.
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -0800983
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500984config BLK_CGROUP
985 bool "IO controller"
986 depends on BLOCK
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700987 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500988 ---help---
989 Generic block IO controller cgroup interface. This is the common
990 cgroup interface which should be used by various IO controlling
991 policies.
Aneesh Kumar K.V2bc64a22012-07-31 16:42:12 -0700992
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500993 Currently, CFQ IO scheduler uses it to recognize task groups and
994 control disk bandwidth allocation (proportional time slice allocation)
995 to such task groups. It is also used by bio throttling logic in
996 block layer to implement upper limit in IO rates on a device.
Stephane Eraniane5d13672011-02-14 11:20:01 +0200997
Johannes Weiner6bf024e2015-12-17 17:19:57 -0500998 This option only enables generic Block IO controller infrastructure.
999 One needs to also enable actual IO controlling logic/policy. For
1000 enabling proportional weight division of disk bandwidth in CFQ, set
1001 CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set
1002 CONFIG_BLK_DEV_THROTTLING=y.
1003
1004 See Documentation/cgroups/blkio-controller.txt for more information.
1005
1006config DEBUG_BLK_CGROUP
1007 bool "IO controller debugging"
1008 depends on BLK_CGROUP
1009 default n
1010 ---help---
1011 Enable some debugging help. Currently it exports additional stat
1012 files in a cgroup which can be useful for debugging.
1013
1014config CGROUP_WRITEBACK
1015 bool
1016 depends on MEMCG && BLK_CGROUP
1017 default y
Stephane Eraniane5d13672011-02-14 11:20:01 +02001018
Dhaval Giani7c941432010-01-20 13:26:18 +01001019menuconfig CGROUP_SCHED
Johannes Weinera0166ec2015-12-17 17:19:56 -05001020 bool "CPU controller"
Dhaval Giani7c941432010-01-20 13:26:18 +01001021 default n
1022 help
1023 This feature lets CPU scheduler recognize task groups and control CPU
1024 bandwidth allocation to such task groups. It uses cgroups to group
1025 tasks.
1026
1027if CGROUP_SCHED
1028config FAIR_GROUP_SCHED
1029 bool "Group scheduling for SCHED_OTHER"
1030 depends on CGROUP_SCHED
1031 default CGROUP_SCHED
1032
Paul Turnerab84d312011-07-21 09:43:28 -07001033config CFS_BANDWIDTH
1034 bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
Paul Turnerab84d312011-07-21 09:43:28 -07001035 depends on FAIR_GROUP_SCHED
1036 default n
1037 help
1038 This option allows users to define CPU bandwidth rates (limits) for
1039 tasks running within the fair group scheduler. Groups with no limit
1040 set are considered to be unconstrained and will run with no
1041 restriction.
1042 See tip/Documentation/scheduler/sched-bwc.txt for more information.
1043
Dhaval Giani7c941432010-01-20 13:26:18 +01001044config RT_GROUP_SCHED
1045 bool "Group scheduling for SCHED_RR/FIFO"
Dhaval Giani7c941432010-01-20 13:26:18 +01001046 depends on CGROUP_SCHED
1047 default n
1048 help
1049 This feature lets you explicitly allocate real CPU bandwidth
Li Zefan32bd7eb2010-03-24 13:17:19 +08001050 to task groups. If enabled, it will also make it impossible to
Dhaval Giani7c941432010-01-20 13:26:18 +01001051 schedule realtime tasks for non-root users until you allocate
1052 realtime bandwidth for them.
1053 See Documentation/scheduler/sched-rt-group.txt for more information.
1054
1055endif #CGROUP_SCHED
1056
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001057config CGROUP_PIDS
1058 bool "PIDs controller"
1059 help
1060 Provides enforcement of process number limits in the scope of a
1061 cgroup. Any attempt to fork more processes than is allowed in the
1062 cgroup will fail. PIDs are fundamentally a global resource because it
1063 is fairly trivial to reach PID exhaustion before you reach even a
1064 conservative kmemcg limit. As a result, it is possible to grind a
1065 system to halt without being limited by other cgroup policies. The
1066 PIDs cgroup subsystem is designed to stop this from happening.
1067
1068 It should be noted that organisational operations (such as attaching
1069 to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
1070 since the PIDs limit only affects a process's ability to fork, not to
1071 attach to a cgroup.
1072
1073config CGROUP_FREEZER
1074 bool "Freezer controller"
1075 help
1076 Provides a way to freeze and unfreeze all tasks in a
1077 cgroup.
1078
1079config CGROUP_HUGETLB
1080 bool "HugeTLB controller"
1081 depends on HUGETLB_PAGE
1082 select PAGE_COUNTER
Vivek Goyalafc24d42010-04-26 19:27:56 +02001083 default n
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001084 help
1085 Provides a cgroup controller for HugeTLB pages.
1086 When you enable this, you can put a per cgroup limit on HugeTLB usage.
1087 The limit is enforced during page fault. Since HugeTLB doesn't
1088 support page reclaim, enforcing the limit at page fault time implies
1089 that, the application will get SIGBUS signal if it tries to access
1090 HugeTLB pages beyond its limit. This requires the application to know
1091 beforehand how much HugeTLB pages it would require for its use. The
1092 control group is tracked in the third page lru pointer. This means
1093 that we cannot use the controller with huge page less than 3 pages.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001094
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001095config CPUSETS
1096 bool "Cpuset controller"
1097 help
1098 This option will let you create and manage CPUSETs which
1099 allow dynamically partitioning a system into sets of CPUs and
1100 Memory Nodes and assigning tasks to run only within those sets.
1101 This is primarily useful on large SMP or NUMA systems.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001102
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001103 Say N if unsure.
Vivek Goyalafc24d42010-04-26 19:27:56 +02001104
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001105config PROC_PID_CPUSET
1106 bool "Include legacy /proc/<pid>/cpuset file"
1107 depends on CPUSETS
Tejun Heo89e9b9e2015-05-22 17:13:36 -04001108 default y
1109
Johannes Weiner6bf024e2015-12-17 17:19:57 -05001110config CGROUP_DEVICE
1111 bool "Device controller"
1112 help
1113 Provides a cgroup controller implementing whitelists for
1114 devices which a process in the cgroup can mknod or open.
1115
1116config CGROUP_CPUACCT
1117 bool "Simple CPU accounting controller"
1118 help
1119 Provides a simple controller for monitoring the
1120 total CPU consumed by the tasks in a cgroup.
1121
1122config CGROUP_PERF
1123 bool "Perf controller"
1124 depends on PERF_EVENTS
1125 help
1126 This option extends the perf per-cpu mode to restrict monitoring
1127 to threads which belong to the cgroup specified and run on the
1128 designated cpu.
1129
1130 Say N if unsure.
1131
1132config CGROUP_DEBUG
1133 bool "Example controller"
1134 default n
1135 help
1136 This option enables a simple controller that exports
1137 debugging information about the cgroups framework.
1138
1139 Say N.
1140
Li Zefan23964d22009-01-15 13:50:58 -08001141endif # CGROUPS
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001142
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001143config CHECKPOINT_RESTORE
1144 bool "Checkpoint/restore support" if EXPERT
Iago López Galeiras2e13ba52015-06-25 15:00:57 -07001145 select PROC_CHILDREN
Cyrill Gorcunov067bce12012-01-12 17:20:49 -08001146 default n
1147 help
1148 Enables additional kernel features in a sake of checkpoint/restore.
1149 In particular it adds auxiliary prctl codes to setup process text,
1150 data and heap segment sizes, and a few additional /proc filesystem
1151 entries.
1152
1153 If unsure, say N here.
1154
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001155menuconfig NAMESPACES
David Rientjes6a108a12011-01-20 14:44:16 -08001156 bool "Namespaces support" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001157 depends on MULTIUSER
David Rientjes6a108a12011-01-20 14:44:16 -08001158 default !EXPERT
Pavel Emelyanovc5289a62008-02-08 04:18:19 -08001159 help
1160 Provides the way to make tasks work with different objects using
1161 the same id. For example same IPC id may refer to different objects
1162 or same user id or pid may refer to different tasks when used in
1163 different namespaces.
1164
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001165if NAMESPACES
1166
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001167config UTS_NS
1168 bool "UTS namespace"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001169 default y
Pavel Emelyanov58bfdd6d2008-02-08 04:18:21 -08001170 help
1171 In this namespace tasks see different info provided with the
1172 uname() system call
1173
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001174config IPC_NS
1175 bool "IPC namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001176 depends on (SYSVIPC || POSIX_MQUEUE)
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001177 default y
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001178 help
1179 In this namespace tasks work with IPC ids which correspond to
Serge E. Hallyn614b84c2009-04-06 19:01:08 -07001180 different IPC objects in different namespaces.
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001181
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001182config USER_NS
Kees Cook19c92392012-10-02 11:19:29 -07001183 bool "User namespace"
Eric W. Biederman5673a942011-11-17 10:23:55 -08001184 default n
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001185 help
1186 This allows containers, i.e. vservers, to use user namespaces
1187 to provide different user info for different servers.
Eric W. Biedermane11f0ae2013-01-25 16:48:31 -08001188
1189 When user namespaces are enabled in the kernel it is
1190 recommended that the MEMCG and MEMCG_KMEM options also be
1191 enabled and that user-space use the memory control groups to
1192 limit the amount of memory a memory unprivileged users can
1193 use.
1194
Pavel Emelyanovaee16ce2008-02-08 04:18:23 -08001195 If unsure, say N.
1196
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001197config PID_NS
Daniel Lezcano9bd38c22010-10-27 15:34:37 -07001198 bool "PID Namespaces"
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001199 default y
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001200 help
Heikki Orsila12d2b8f2008-07-06 15:48:02 +03001201 Support process id namespaces. This allows having multiple
Matt LaPlante692105b2009-01-26 11:12:25 +01001202 processes with the same pid as long as they are in different
Pavel Emelyanov74bd59b2008-02-08 04:18:24 -08001203 pid namespaces. This is a building block of containers.
1204
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001205config NET_NS
1206 bool "Network namespace"
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001207 depends on NET
Daniel Lezcano17a6d442010-10-27 15:34:37 -07001208 default y
Matt Helsleyd6eb6332009-01-26 12:25:55 -08001209 help
1210 Allow user space to create what appear to be multiple instances
1211 of the network stack.
1212
Daniel Lezcano8dd2a822010-10-27 15:34:38 -07001213endif # NAMESPACES
1214
Mike Galbraith5091faa2010-11-30 14:18:03 +01001215config SCHED_AUTOGROUP
1216 bool "Automatic process group scheduling"
Mike Galbraith5091faa2010-11-30 14:18:03 +01001217 select CGROUPS
1218 select CGROUP_SCHED
1219 select FAIR_GROUP_SCHED
1220 help
1221 This option optimizes the scheduler for common desktop workloads by
1222 automatically creating and populating task groups. This separation
1223 of workloads isolates aggressive CPU burners (like build jobs) from
1224 desktop applications. Task group autogeneration is currently based
1225 upon task session.
1226
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001227config SYSFS_DEPRECATED
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001228 bool "Enable deprecated sysfs features to support old userspace tools"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001229 depends on SYSFS
1230 default n
1231 help
1232 This option adds code that switches the layout of the "block" class
1233 devices, to not show up in /sys/class/block/, but only in
1234 /sys/block/.
1235
1236 This switch is only active when the sysfs.deprecated=1 boot option is
1237 passed or the SYSFS_DEPRECATED_V2 option is set.
1238
1239 This option allows new kernels to run on old distributions and tools,
1240 which might get confused by /sys/class/block/. Since 2007/2008 all
1241 major distributions and tools handle this just fine.
1242
1243 Recent distributions and userspace tools after 2009/2010 depend on
1244 the existence of /sys/class/block/, and will not work with this
1245 option enabled.
1246
1247 Only if you are using a new kernel on an old distribution, you might
1248 need to say Y here.
1249
1250config SYSFS_DEPRECATED_V2
Ferenc Wagner5d6a4ea2011-01-10 19:04:22 +01001251 bool "Enable deprecated sysfs features by default"
Daniel Lezcano7af37be2010-10-27 15:34:41 -07001252 default n
1253 depends on SYSFS
1254 depends on SYSFS_DEPRECATED
1255 help
1256 Enable deprecated sysfs by default.
1257
1258 See the CONFIG_SYSFS_DEPRECATED option for more details about this
1259 option.
1260
1261 Only if you are using a new kernel on an old distribution, you might
1262 need to say Y here. Even then, odds are you would not need it
1263 enabled, you can always pass the boot option if absolutely necessary.
1264
1265config RELAY
1266 bool "Kernel->user space relay support (formerly relayfs)"
1267 help
1268 This option enables support for relay interface support in
1269 certain file systems (such as debugfs).
1270 It is designed to provide an efficient mechanism for tools and
1271 facilities to relay large amounts of data from kernel space to
1272 user space.
1273
1274 If unsure, say N.
1275
Dimitri Gorokhovikf9916332007-03-06 01:42:17 -08001276config BLK_DEV_INITRD
1277 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
1278 depends on BROKEN || !FRV
1279 help
1280 The initial RAM filesystem is a ramfs which is loaded by the
1281 boot loader (loadlin or lilo) and that is mounted as root
1282 before the normal boot procedure. It is typically used to
1283 load modules needed to mount the "real" root file system,
1284 etc. See <file:Documentation/initrd.txt> for details.
1285
1286 If RAM disk support (BLK_DEV_RAM) is also included, this
1287 also enables initial RAM disk (initrd) support and adds
1288 15 Kbytes (more on some other architectures) to the kernel size.
1289
1290 If unsure say Y.
1291
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001292if BLK_DEV_INITRD
1293
Sam Ravnborgdbec4862005-08-10 20:44:50 +02001294source "usr/Kconfig"
1295
Jean-Paul Samanc33df4e2007-02-10 01:44:43 -08001296endif
1297
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001298config CC_OPTIMIZE_FOR_SIZE
Ingo Molnar96fffeb2008-04-28 01:39:43 +02001299 bool "Optimize for size"
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001300 help
Masahiro Yamada31a4af72014-08-05 14:43:07 +09001301 Enabling this option will pass "-Os" instead of "-O2" to
1302 your compiler resulting in a smaller kernel.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001303
Kirill Smelkov3a55fb02012-11-02 15:41:01 +04001304 If unsure, say N.
Linus Torvaldsc45b4f12005-12-14 18:52:21 -08001305
Randy Dunlap08470622006-09-30 23:28:13 -07001306config SYSCTL
1307 bool
1308
Randy Dunlapb943c462009-03-10 12:55:46 -07001309config ANON_INODES
1310 bool
1311
Mike Frysinger657a5202013-04-30 15:28:45 -07001312config HAVE_UID16
1313 bool
1314
1315config SYSCTL_EXCEPTION_TRACE
1316 bool
1317 help
1318 Enable support for /proc/sys/debug/exception-trace.
1319
1320config SYSCTL_ARCH_UNALIGN_NO_WARN
1321 bool
1322 help
1323 Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
1324 Allows arch to define/use @no_unaligned_warning to possibly warn
1325 about unaligned access emulation going on under the hood.
1326
1327config SYSCTL_ARCH_UNALIGN_ALLOW
1328 bool
1329 help
1330 Enable support for /proc/sys/kernel/unaligned-trap
1331 Allows arches to define/use @unaligned_enabled to runtime toggle
1332 the unaligned access emulation.
1333 see arch/parisc/kernel/unaligned.c for reference
1334
Mike Frysinger657a5202013-04-30 15:28:45 -07001335config HAVE_PCSPKR_PLATFORM
1336 bool
1337
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001338# interpreter that classic socket filters depend on
1339config BPF
1340 bool
1341
David Rientjes6a108a12011-01-20 14:44:16 -08001342menuconfig EXPERT
1343 bool "Configure standard kernel features (expert users)"
Josh Triplettf505c552011-06-05 18:23:58 -07001344 # Unhide debug options, to make the on-by-default options visible
1345 select DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 help
1347 This option allows certain base kernel options and settings
1348 to be disabled or tweaked. This is for specialized
1349 environments which can tolerate a "non-standard" kernel.
1350 Only use this if you really know what you are doing.
1351
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001352config UID16
David Rientjes6a108a12011-01-20 14:44:16 -08001353 bool "Enable 16-bit UID system calls" if EXPERT
Iulia Manda28138932015-04-15 16:16:41 -07001354 depends on HAVE_UID16 && MULTIUSER
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001355 default y
1356 help
1357 This enables the legacy 16-bit UID syscall wrappers.
1358
Iulia Manda28138932015-04-15 16:16:41 -07001359config MULTIUSER
1360 bool "Multiple users, groups and capabilities support" if EXPERT
1361 default y
1362 help
1363 This option enables support for non-root users, groups and
1364 capabilities.
1365
1366 If you say N here, all processes will run with UID 0, GID 0, and all
1367 possible capabilities. Saying N here also compiles out support for
1368 system calls related to UIDs, GIDs, and capabilities, such as setuid,
1369 setgid, and capset.
1370
1371 If unsure, say Y here.
1372
Fabian Frederickf6187762014-06-04 16:11:12 -07001373config SGETMASK_SYSCALL
1374 bool "sgetmask/ssetmask syscalls support" if EXPERT
1375 def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH
1376 ---help---
1377 sys_sgetmask and sys_ssetmask are obsolete system calls
1378 no longer supported in libc but still enabled by default in some
1379 architectures.
1380
1381 If unsure, leave the default option here.
1382
Fabian Frederick6af9f7b2014-04-03 14:48:25 -07001383config SYSFS_SYSCALL
1384 bool "Sysfs syscall support" if EXPERT
1385 default y
1386 ---help---
1387 sys_sysfs is an obsolete system call no longer supported in libc.
1388 Note that disabling this option is more secure but might break
1389 compatibility with some systems.
1390
1391 If unsure say Y here.
1392
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001393config SYSCTL_SYSCALL
David Rientjes6a108a12011-01-20 14:44:16 -08001394 bool "Sysctl syscall support" if EXPERT
Eric W. Biederman26a70342009-11-05 05:26:41 -08001395 depends on PROC_SYSCTL
WANG Congc736de62011-11-02 13:39:25 -07001396 default n
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001397 select SYSCTL
1398 ---help---
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001399 sys_sysctl uses binary paths that have been found challenging
1400 to properly maintain and use. The interface in /proc/sys
1401 using paths with ascii names is now the primary path to this
1402 information.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001403
Eric W. Biederman13bb7e32006-11-08 17:44:51 -08001404 Almost nothing using the binary sysctl interface so if you are
1405 trying to save some space it is probably safe to disable this,
1406 making your kernel marginally smaller.
Eric W. Biedermanb89a8172006-09-27 01:51:04 -07001407
WANG Congc736de62011-11-02 13:39:25 -07001408 If unsure say N here.
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001409
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410config KALLSYMS
David Rientjes6a108a12011-01-20 14:44:16 -08001411 bool "Load all symbols for debugging/ksymoops" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 default y
1413 help
1414 Say Y here to let the kernel print out symbolic crash information and
1415 symbolic stack backtraces. This increases the size of the kernel
1416 somewhat, as all symbols have to be loaded into the kernel image.
1417
1418config KALLSYMS_ALL
1419 bool "Include all symbols in kallsyms"
1420 depends on DEBUG_KERNEL && KALLSYMS
1421 help
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001422 Normally kallsyms only contains the symbols of functions for nicer
1423 OOPS messages and backtraces (i.e., symbols from the text and inittext
1424 sections). This is sufficient for most cases. And only in very rare
1425 cases (e.g., when a debugger is used) all symbols are required (e.g.,
1426 names of variables from the data sections, etc).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001428 This option makes sure that all symbols are loaded into the kernel
1429 image (i.e., symbols from all sections) in cost of increased kernel
1430 size (depending on the kernel configuration, it may be 300KiB or
1431 something like this).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432
Artem Bityutskiy71a83ec2011-04-05 13:24:57 +03001433 Say N unless you really need all symbols.
Matt Mackalld59745c2005-05-01 08:59:02 -07001434
1435config PRINTK
1436 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001437 bool "Enable support for printk" if EXPERT
Frederic Weisbecker74876a92012-10-12 18:00:23 +02001438 select IRQ_WORK
Matt Mackalld59745c2005-05-01 08:59:02 -07001439 help
1440 This option enables normal printk support. Removing it
1441 eliminates most of the message strings from the kernel image
1442 and makes the kernel more or less silent. As this makes it
1443 very difficult to diagnose system problems, saying N here is
1444 strongly discouraged.
1445
Matt Mackallc8538a72005-05-01 08:59:01 -07001446config BUG
David Rientjes6a108a12011-01-20 14:44:16 -08001447 bool "BUG() support" if EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -07001448 default y
1449 help
1450 Disabling this option eliminates support for BUG and WARN, reducing
1451 the size of your kernel image and potentially quietly ignoring
1452 numerous fatal conditions. You should only consider disabling this
1453 option for embedded systems with no facilities for reporting errors.
1454 Just say Y.
1455
Matt Mackall708e9a72006-01-08 01:05:25 -08001456config ELF_CORE
Alex Kelly046d6622012-10-04 17:15:23 -07001457 depends on COREDUMP
Matt Mackall708e9a72006-01-08 01:05:25 -08001458 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001459 bool "Enable ELF core dumps" if EXPERT
Matt Mackall708e9a72006-01-08 01:05:25 -08001460 help
1461 Enable support for generating core dumps. Disabling saves about 4k.
1462
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001463
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001464config PCSPKR_PLATFORM
David Rientjes6a108a12011-01-20 14:44:16 -08001465 bool "Enable PC-Speaker support" if EXPERT
Ralf Baechle8761f1a2011-06-01 19:05:09 +01001466 depends on HAVE_PCSPKR_PLATFORM
Ralf Baechle15f304b2011-06-01 19:04:59 +01001467 select I8253_LOCK
Stas Sergeeve5e1d3c2008-05-07 12:39:56 +02001468 default y
1469 help
1470 This option allows to disable the internal PC-Speaker
1471 support, saving some memory.
1472
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473config BASE_FULL
1474 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001475 bool "Enable full-sized data structures for core" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 help
1477 Disabling this option reduces the size of miscellaneous core
1478 kernel data structures. This saves memory on small machines,
1479 but may reduce performance.
1480
1481config FUTEX
David Rientjes6a108a12011-01-20 14:44:16 -08001482 bool "Enable futex support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 default y
Ingo Molnar23f78d4a2006-06-27 02:54:53 -07001484 select RT_MUTEXES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 help
1486 Disabling this option will cause the kernel to be built without
1487 support for "fast userspace mutexes". The resulting kernel may not
1488 run glibc-based applications correctly.
1489
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001490config HAVE_FUTEX_CMPXCHG
1491 bool
Josh Triplett62b4d202014-10-03 16:19:24 -07001492 depends on FUTEX
Heiko Carstens03b8c7b2014-03-02 13:09:47 +01001493 help
1494 Architectures should select this if futex_atomic_cmpxchg_inatomic()
1495 is implemented and always working. This removes a couple of runtime
1496 checks.
1497
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498config EPOLL
David Rientjes6a108a12011-01-20 14:44:16 -08001499 bool "Enable eventpoll support" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 default y
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001501 select ANON_INODES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 help
1503 Disabling this option will cause the kernel to be built without
1504 support for epoll family of system calls.
1505
Davide Libenzifba2afa2007-05-10 22:23:13 -07001506config SIGNALFD
David Rientjes6a108a12011-01-20 14:44:16 -08001507 bool "Enable signalfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001508 select ANON_INODES
Davide Libenzifba2afa2007-05-10 22:23:13 -07001509 default y
1510 help
1511 Enable the signalfd() system call that allows to receive signals
1512 on a file descriptor.
1513
1514 If unsure, say Y.
1515
Davide Libenzib215e282007-05-10 22:23:16 -07001516config TIMERFD
David Rientjes6a108a12011-01-20 14:44:16 -08001517 bool "Enable timerfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001518 select ANON_INODES
Davide Libenzib215e282007-05-10 22:23:16 -07001519 default y
1520 help
1521 Enable the timerfd() system call that allows to receive timer
1522 events on a file descriptor.
1523
1524 If unsure, say Y.
1525
Davide Libenzie1ad7462007-05-10 22:23:19 -07001526config EVENTFD
David Rientjes6a108a12011-01-20 14:44:16 -08001527 bool "Enable eventfd() system call" if EXPERT
Adrian Bunk448e3ce2007-07-31 00:39:10 -07001528 select ANON_INODES
Davide Libenzie1ad7462007-05-10 22:23:19 -07001529 default y
1530 help
1531 Enable the eventfd() system call that allows to receive both
1532 kernel notification (ie. KAIO) or userspace notifications.
1533
1534 If unsure, say Y.
1535
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001536# syscall, maps, verifier
1537config BPF_SYSCALL
Ingo Molnare1abf2c2015-04-02 15:51:39 +02001538 bool "Enable bpf() system call"
Alexei Starovoitovf89b7752014-10-23 18:41:08 -07001539 select ANON_INODES
1540 select BPF
1541 default n
1542 help
1543 Enable the bpf() system call that allows to manipulate eBPF
1544 programs and maps via file descriptors.
1545
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546config SHMEM
David Rientjes6a108a12011-01-20 14:44:16 -08001547 bool "Use full shmem filesystem" if EXPERT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548 default y
1549 depends on MMU
1550 help
1551 The shmem is an internal filesystem used to manage shared memory.
1552 It is backed by swap and manages resource limits. It is also exported
1553 to userspace as tmpfs if TMPFS is enabled. Disabling this
1554 option replaces shmem and tmpfs with the much simpler ramfs code,
1555 which may be appropriate on small systems without swap.
1556
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001557config AIO
David Rientjes6a108a12011-01-20 14:44:16 -08001558 bool "Enable AIO support" if EXPERT
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001559 default y
1560 help
1561 This option enables POSIX asynchronous I/O which may by used
Mike Frysinger657a5202013-04-30 15:28:45 -07001562 by some high performance threaded applications. Disabling
1563 this option saves about 7k.
1564
Josh Triplettd3ac21c2014-08-17 19:41:09 -05001565config ADVISE_SYSCALLS
1566 bool "Enable madvise/fadvise syscalls" if EXPERT
1567 default y
1568 help
1569 This option enables the madvise and fadvise syscalls, used by
1570 applications to advise the kernel about their future memory or file
1571 usage, improving performance. If building an embedded system where no
1572 applications use these syscalls, you can disable this option to save
1573 space.
1574
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001575config USERFAULTFD
1576 bool "Enable userfaultfd() system call"
1577 select ANON_INODES
Andrea Arcangelia14c1512015-09-04 15:46:54 -07001578 depends on MMU
1579 help
1580 Enable the userfaultfd() system call that allows to intercept and
1581 handle page faults in userland.
1582
Mike Frysinger657a5202013-04-30 15:28:45 -07001583config PCI_QUIRKS
1584 default y
1585 bool "Enable PCI quirk workarounds" if EXPERT
1586 depends on PCI
1587 help
1588 This enables workarounds for various PCI chipset
1589 bugs/quirks. Disable this only if your target machine is
1590 unaffected by PCI quirks.
Thomas Petazzoniebf3f092008-10-15 22:05:12 -07001591
Mathieu Desnoyers5b25b132015-09-11 13:07:39 -07001592config MEMBARRIER
1593 bool "Enable membarrier() system call" if EXPERT
1594 default y
1595 help
1596 Enable the membarrier() system call that allows issuing memory
1597 barriers across all running threads, which can be used to distribute
1598 the cost of user-space memory barriers asymmetrically by transforming
1599 pairs of memory barriers into pairs consisting of membarrier() and a
1600 compiler barrier.
1601
1602 If unsure, say Y.
1603
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001604config EMBEDDED
1605 bool "Embedded system"
Josh Triplett5d2acfc2014-04-07 15:39:09 -07001606 option allnoconfig_y
Randy Dunlap6befe5f2011-04-26 12:33:21 -07001607 select EXPERT
1608 help
1609 This option should be enabled if compiling the kernel for
1610 an embedded system so certain expert options are available
1611 for configuration.
1612
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001613config HAVE_PERF_EVENTS
Thomas Gleixner0793a612008-12-04 20:12:29 +01001614 bool
Mike Frysinger018df722009-06-12 13:17:43 -04001615 help
1616 See tools/perf/design.txt for details.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001617
Peter Zijlstra906010b2009-09-21 16:08:49 +02001618config PERF_USE_VMALLOC
1619 bool
1620 help
1621 See tools/perf/design.txt for details
1622
Ingo Molnar57c0c152009-09-21 12:20:38 +02001623menu "Kernel Performance Events And Counters"
Thomas Gleixner0793a612008-12-04 20:12:29 +01001624
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001625config PERF_EVENTS
Ingo Molnar57c0c152009-09-21 12:20:38 +02001626 bool "Kernel performance events and counters"
Robert Richter392d65a2012-04-05 18:24:44 +02001627 default y if PROFILING
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001628 depends on HAVE_PERF_EVENTS
Ingo Molnar4c59e462008-12-08 19:38:33 +01001629 select ANON_INODES
Peter Zijlstrae360adb2010-10-14 14:01:34 +08001630 select IRQ_WORK
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001631 select SRCU
Thomas Gleixner0793a612008-12-04 20:12:29 +01001632 help
Ingo Molnar57c0c152009-09-21 12:20:38 +02001633 Enable kernel support for various performance events provided
1634 by software and hardware.
Thomas Gleixner0793a612008-12-04 20:12:29 +01001635
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001636 Software events are supported either built-in or via the
Ingo Molnar57c0c152009-09-21 12:20:38 +02001637 use of generic tracepoints.
1638
1639 Most modern CPUs support performance events via performance
1640 counter registers. These registers count the number of certain
Thomas Gleixner0793a612008-12-04 20:12:29 +01001641 types of hw events: such as instructions executed, cachemisses
1642 suffered, or branches mis-predicted - without slowing down the
1643 kernel or applications. These registers can also trigger interrupts
1644 when a threshold number of events have passed - and can thus be
1645 used to profile the code that runs on that CPU.
1646
Ingo Molnar57c0c152009-09-21 12:20:38 +02001647 The Linux Performance Event subsystem provides an abstraction of
Thadeu Lima de Souza Cascardodd770382009-10-30 19:32:25 -02001648 these software and hardware event capabilities, available via a
Ingo Molnar57c0c152009-09-21 12:20:38 +02001649 system call and used by the "perf" utility in tools/perf/. It
Thomas Gleixner0793a612008-12-04 20:12:29 +01001650 provides per task and per CPU counters, and it provides event
1651 capabilities on top of those.
1652
1653 Say Y if unsure.
1654
Peter Zijlstra906010b2009-09-21 16:08:49 +02001655config DEBUG_PERF_USE_VMALLOC
1656 default n
1657 bool "Debug: use vmalloc to back perf mmap() buffers"
Michael Ellermancb307112015-05-04 16:26:39 +10001658 depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
Peter Zijlstra906010b2009-09-21 16:08:49 +02001659 select PERF_USE_VMALLOC
1660 help
1661 Use vmalloc memory to back perf mmap() buffers.
1662
1663 Mostly useful for debugging the vmalloc code on platforms
1664 that don't require it.
1665
1666 Say N if unsure.
1667
Thomas Gleixner0793a612008-12-04 20:12:29 +01001668endmenu
1669
Christoph Lameterf8891e52006-06-30 01:55:45 -07001670config VM_EVENT_COUNTERS
1671 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001672 bool "Enable VM event counters for /proc/vmstat" if EXPERT
Christoph Lameterf8891e52006-06-30 01:55:45 -07001673 help
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001674 VM event counters are needed for event counts to be shown.
1675 This option allows the disabling of the VM event counters
David Rientjes6a108a12011-01-20 14:44:16 -08001676 on EXPERT systems. /proc/vmstat will only show page counts
Paul Jackson2aea4fb2006-12-22 01:06:10 -08001677 if VM event counters are disabled.
Christoph Lameterf8891e52006-06-30 01:55:45 -07001678
Christoph Lameter41ecc552007-05-09 02:32:44 -07001679config SLUB_DEBUG
1680 default y
David Rientjes6a108a12011-01-20 14:44:16 -08001681 bool "Enable SLUB debugging support" if EXPERT
Christoph Lameterf6acb632008-04-29 16:16:06 -07001682 depends on SLUB && SYSFS
Christoph Lameter41ecc552007-05-09 02:32:44 -07001683 help
1684 SLUB has extensive debug support features. Disabling these can
1685 result in significant savings in code size. This also disables
1686 SLUB sysfs support. /sys/slab will not exist and there will be
1687 no support for cache validation etc.
1688
Randy Dunlapb943c462009-03-10 12:55:46 -07001689config COMPAT_BRK
1690 bool "Disable heap randomization"
1691 default y
1692 help
1693 Randomizing heap placement makes heap exploits harder, but it
1694 also breaks ancient binaries (including anything libc5 based).
1695 This option changes the bootup default to heap randomization
Matt LaPlante692105b2009-01-26 11:12:25 +01001696 disabled, and can be overridden at runtime by setting
Randy Dunlapb943c462009-03-10 12:55:46 -07001697 /proc/sys/kernel/randomize_va_space to 2.
1698
1699 On non-ancient distros (post-2000 ones) N is usually a safe choice.
1700
Christoph Lameter81819f02007-05-06 14:49:36 -07001701choice
1702 prompt "Choose SLAB allocator"
Christoph Lametera0acd822007-07-17 04:03:32 -07001703 default SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001704 help
1705 This option allows to select a slab allocator.
1706
1707config SLAB
1708 bool "SLAB"
1709 help
1710 The regular slab allocator that is established and known to work
Christoph Lameter34013882007-05-09 02:32:47 -07001711 well in all environments. It organizes cache hot objects in
Simon Arlott02f56212008-11-05 22:18:19 +00001712 per cpu and per node queues.
Christoph Lameter81819f02007-05-06 14:49:36 -07001713
1714config SLUB
Christoph Lameter81819f02007-05-06 14:49:36 -07001715 bool "SLUB (Unqueued Allocator)"
1716 help
1717 SLUB is a slab allocator that minimizes cache line usage
1718 instead of managing queues of cached objects (SLAB approach).
1719 Per cpu caching is realized using slabs of objects instead
1720 of queues of objects. SLUB can use memory efficiently
Simon Arlott02f56212008-11-05 22:18:19 +00001721 and has enhanced diagnostics. SLUB is the default choice for
1722 a slab allocator.
Christoph Lameter81819f02007-05-06 14:49:36 -07001723
1724config SLOB
David Rientjes6a108a12011-01-20 14:44:16 -08001725 depends on EXPERT
Christoph Lameter81819f02007-05-06 14:49:36 -07001726 bool "SLOB (Simple Allocator)"
1727 help
Matt Mackall37291452008-02-04 22:29:38 -08001728 SLOB replaces the stock allocator with a drastically simpler
1729 allocator. SLOB is generally more space efficient but
1730 does not perform as well on large systems.
Christoph Lameter81819f02007-05-06 14:49:36 -07001731
1732endchoice
1733
Joonsoo Kim345c9052013-06-19 14:05:52 +09001734config SLUB_CPU_PARTIAL
1735 default y
Uwe Kleine-Königb39ffbf2013-07-17 16:54:59 +02001736 depends on SLUB && SMP
Joonsoo Kim345c9052013-06-19 14:05:52 +09001737 bool "SLUB per cpu partial cache"
1738 help
1739 Per cpu partial caches accellerate objects allocation and freeing
1740 that is local to a processor at the price of more indeterminism
1741 in the latency of the free. On overflow these caches will be cleared
1742 which requires the taking of locks that may cause latency spikes.
1743 Typically one would choose no for a realtime system.
1744
Jie Zhangea637632009-12-14 18:00:02 -08001745config MMAP_ALLOW_UNINITIALIZED
1746 bool "Allow mmapped anonymous memory to be uninitialized"
David Rientjes6a108a12011-01-20 14:44:16 -08001747 depends on EXPERT && !MMU
Jie Zhangea637632009-12-14 18:00:02 -08001748 default n
1749 help
1750 Normally, and according to the Linux spec, anonymous memory obtained
1751 from mmap() has it's contents cleared before it is passed to
1752 userspace. Enabling this config option allows you to request that
1753 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
1754 providing a huge performance boost. If this option is not enabled,
1755 then the flag will be ignored.
1756
1757 This is taken advantage of by uClibc's malloc(), and also by
1758 ELF-FDPIC binfmt's brk and stack allocator.
1759
1760 Because of the obvious security issues, this option should only be
1761 enabled on embedded devices where you control what is run in
1762 userspace. Since that isn't generally a problem on no-MMU systems,
1763 it is normally safe to say Y here.
1764
1765 See Documentation/nommu-mmap.txt for more information.
1766
David Howells091f6e22015-07-20 21:16:28 +01001767config SYSTEM_DATA_VERIFICATION
1768 def_bool n
1769 select SYSTEM_TRUSTED_KEYRING
1770 select KEYS
1771 select CRYPTO
1772 select ASYMMETRIC_KEY_TYPE
1773 select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
1774 select PUBLIC_KEY_ALGO_RSA
1775 select ASN1
1776 select OID_REGISTRY
1777 select X509_CERTIFICATE_PARSER
1778 select PKCS7_MESSAGE_PARSER
Peter Foley82c04ff2014-04-18 15:07:11 -07001779 help
David Howells091f6e22015-07-20 21:16:28 +01001780 Provide PKCS#7 message verification using the contents of the system
1781 trusted keyring to provide public keys. This then can be used for
1782 module verification, kexec image verification and firmware blob
1783 verification.
Peter Foley82c04ff2014-04-18 15:07:11 -07001784
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001785config PROFILING
Robert Richterb309a292010-02-26 15:01:23 +01001786 bool "Profiling support"
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05001787 help
1788 Say Y here to enable the extended profiling support mechanisms used
1789 by profilers such as OProfile.
1790
Ingo Molnar5f87f112008-07-23 14:15:22 +02001791#
1792# Place an empty function call at each tracepoint site. Can be
1793# dynamically changed for a probe function.
1794#
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001795config TRACEPOINTS
Ingo Molnar5f87f112008-07-23 14:15:22 +02001796 bool
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001797
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05001798source "arch/Kconfig"
1799
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800endmenu # General setup
1801
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +04001802config HAVE_GENERIC_DMA_COHERENT
1803 bool
1804 default n
1805
Linus Torvalds158a9622008-01-02 13:04:48 -08001806config SLABINFO
1807 bool
1808 depends on PROC_FS
Christoph Lameter0f389ec2008-04-14 18:53:02 +03001809 depends on SLAB || SLUB_DEBUG
Linus Torvalds158a9622008-01-02 13:04:48 -08001810 default y
1811
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001812config RT_MUTEXES
Christoph Jaeger6341e622014-12-20 15:41:11 -05001813 bool
Chuck Ebbertae81f9e2006-09-16 12:15:53 -07001814
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815config BASE_SMALL
1816 int
1817 default 0 if BASE_FULL
1818 default 1 if !BASE_FULL
1819
Jan Engelhardt66da5732007-07-15 23:39:29 -07001820menuconfig MODULES
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 bool "Enable loadable module support"
Yann E. MORIN11097a02013-08-11 16:07:50 +02001822 option modules
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 help
1824 Kernel modules are small pieces of compiled code which can
1825 be inserted in the running kernel, rather than being
1826 permanently built into the kernel. You use the "modprobe"
1827 tool to add (and sometimes remove) them. If you say Y here,
1828 many parts of the kernel can be built as modules (by
1829 answering M instead of Y where indicated): this is most
1830 useful for infrequently used options which are not required
1831 for booting. For more information, see the man pages for
1832 modprobe, lsmod, modinfo, insmod and rmmod.
1833
1834 If you say Y here, you will need to run "make
1835 modules_install" to put the modules under /lib/modules/
1836 where modprobe can find them (you may need to be root to do
1837 this).
1838
1839 If unsure, say Y.
1840
Robert P. J. Day0b0de142008-08-04 13:31:32 -04001841if MODULES
1842
Linus Torvalds826e4502008-05-04 17:04:16 -07001843config MODULE_FORCE_LOAD
1844 bool "Forced module loading"
Linus Torvalds826e4502008-05-04 17:04:16 -07001845 default n
1846 help
Rusty Russell91e37a72008-05-09 16:25:28 +10001847 Allow loading of modules without version information (ie. modprobe
1848 --force). Forced module loading sets the 'F' (forced) taint flag and
1849 is usually a really bad idea.
Linus Torvalds826e4502008-05-04 17:04:16 -07001850
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851config MODULE_UNLOAD
1852 bool "Module unloading"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853 help
1854 Without this option you will not be able to unload any
1855 modules (note that some modules may not be unloadable
Denys Vlasenkof7f5b672008-07-22 19:24:26 -05001856 anyway), which makes your kernel smaller, faster
1857 and simpler. If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858
1859config MODULE_FORCE_UNLOAD
1860 bool "Forced module unloading"
Kees Cook19c92392012-10-02 11:19:29 -07001861 depends on MODULE_UNLOAD
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862 help
1863 This option allows you to force a module to unload, even if the
1864 kernel believes it is unsafe: the kernel will remove the module
1865 without waiting for anyone to stop using it (using the -f option to
1866 rmmod). This is mainly for kernel developers and desperate users.
1867 If unsure, say N.
1868
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869config MODVERSIONS
Sam Ravnborg0d541642005-12-26 23:04:02 +01001870 bool "Module versioning support"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871 help
1872 Usually, you have to use modules compiled with your kernel.
1873 Saying Y here makes it sometimes possible to use modules
1874 compiled for different kernels, by adding enough information
1875 to the modules to (hopefully) spot any changes which would
1876 make them incompatible with the kernel you are running. If
1877 unsure, say N.
1878
1879config MODULE_SRCVERSION_ALL
1880 bool "Source checksum for all modules"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 help
1882 Modules which contain a MODULE_VERSION get an extra "srcversion"
1883 field inserted into their modinfo section, which contains a
1884 sum of the source files which made it. This helps maintainers
1885 see exactly which source was used to build a module (since
1886 others sometimes change the module source without updating
1887 the version). With this option, such a "srcversion" field
1888 will be created for all modules. If unsure, say N.
1889
Rusty Russell106a4ee2012-09-26 10:09:40 +01001890config MODULE_SIG
1891 bool "Module signature verification"
1892 depends on MODULES
David Howells091f6e22015-07-20 21:16:28 +01001893 select SYSTEM_DATA_VERIFICATION
Rusty Russell106a4ee2012-09-26 10:09:40 +01001894 help
1895 Check modules for valid signatures upon load: the signature
1896 is simply appended to the module. For more information see
1897 Documentation/module-signing.txt.
1898
David Howells228c37f2015-08-11 12:38:54 +01001899 Note that this option adds the OpenSSL development packages as a
1900 kernel build dependency so that the signing tool can use its crypto
1901 library.
1902
David Howellsea0b6dc2012-09-26 10:09:50 +01001903 !!!WARNING!!! If you enable this option, you MUST make sure that the
1904 module DOES NOT get stripped after being signed. This includes the
1905 debuginfo strip done by some packagers (such as rpmbuild) and
1906 inclusion into an initramfs that wants the module size reduced.
1907
Rusty Russell106a4ee2012-09-26 10:09:40 +01001908config MODULE_SIG_FORCE
1909 bool "Require modules to be validly signed"
1910 depends on MODULE_SIG
1911 help
1912 Reject unsigned modules or signed modules for which we don't have a
1913 key. Without this, such modules will simply taint the kernel.
David Howellsea0b6dc2012-09-26 10:09:50 +01001914
Michal Marekd9d8d7e2013-01-25 13:41:31 +10301915config MODULE_SIG_ALL
1916 bool "Automatically sign all modules"
1917 default y
1918 depends on MODULE_SIG
1919 help
1920 Sign all modules during make modules_install. Without this option,
1921 modules must be signed manually, using the scripts/sign-file tool.
1922
1923comment "Do not forget to sign required modules with scripts/sign-file"
1924 depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
1925
David Howellsea0b6dc2012-09-26 10:09:50 +01001926choice
1927 prompt "Which hash algorithm should modules be signed with?"
1928 depends on MODULE_SIG
1929 help
1930 This determines which sort of hashing algorithm will be used during
1931 signature generation. This algorithm _must_ be built into the kernel
1932 directly so that signature verification can take place. It is not
1933 possible to load a signed module containing the algorithm to check
1934 the signature on that module.
1935
1936config MODULE_SIG_SHA1
1937 bool "Sign modules with SHA-1"
1938 select CRYPTO_SHA1
1939
1940config MODULE_SIG_SHA224
1941 bool "Sign modules with SHA-224"
1942 select CRYPTO_SHA256
1943
1944config MODULE_SIG_SHA256
1945 bool "Sign modules with SHA-256"
1946 select CRYPTO_SHA256
1947
1948config MODULE_SIG_SHA384
1949 bool "Sign modules with SHA-384"
1950 select CRYPTO_SHA512
1951
1952config MODULE_SIG_SHA512
1953 bool "Sign modules with SHA-512"
1954 select CRYPTO_SHA512
1955
1956endchoice
1957
Michal Marek22753672013-01-25 13:41:00 +10301958config MODULE_SIG_HASH
1959 string
1960 depends on MODULE_SIG
1961 default "sha1" if MODULE_SIG_SHA1
1962 default "sha224" if MODULE_SIG_SHA224
1963 default "sha256" if MODULE_SIG_SHA256
1964 default "sha384" if MODULE_SIG_SHA384
1965 default "sha512" if MODULE_SIG_SHA512
1966
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301967config MODULE_COMPRESS
1968 bool "Compress modules on installation"
1969 depends on MODULES
1970 help
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301971
Rusty Russellb6c09b52015-06-16 12:16:22 +09301972 Compresses kernel modules when 'make modules_install' is run; gzip or
1973 xz depending on "Compression algorithm" below.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301974
Rusty Russellb6c09b52015-06-16 12:16:22 +09301975 module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301976
Rusty Russellb6c09b52015-06-16 12:16:22 +09301977 Out-of-tree kernel modules installed using Kbuild will also be
1978 compressed upon installation.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301979
Rusty Russellb6c09b52015-06-16 12:16:22 +09301980 Note: for modules inside an initrd or initramfs, it's more efficient
1981 to compress the whole initrd or initramfs instead.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301982
Rusty Russellb6c09b52015-06-16 12:16:22 +09301983 Note: This is fully compatible with signed modules.
1984
1985 If in doubt, say N.
Bertrand Jacquinbeb50df2014-08-27 20:31:56 +09301986
1987choice
1988 prompt "Compression algorithm"
1989 depends on MODULE_COMPRESS
1990 default MODULE_COMPRESS_GZIP
1991 help
1992 This determines which sort of compression will be used during
1993 'make modules_install'.
1994
1995 GZIP (default) and XZ are supported.
1996
1997config MODULE_COMPRESS_GZIP
1998 bool "GZIP"
1999
2000config MODULE_COMPRESS_XZ
2001 bool "XZ"
2002
2003endchoice
2004
Robert P. J. Day0b0de142008-08-04 13:31:32 -04002005endif # MODULES
2006
Peter Zijlstra6c9692e2015-05-27 11:09:37 +09302007config MODULES_TREE_LOOKUP
2008 def_bool y
2009 depends on PERF_EVENTS || TRACING
2010
Rusty Russell98a79d62008-12-13 21:19:41 +10302011config INIT_ALL_POSSIBLE
2012 bool
2013 help
Rusty Russell5f054e32012-03-29 15:38:31 +10302014 Back when each arch used to define their own cpu_online_mask and
2015 cpu_possible_mask, some of them chose to initialize cpu_possible_mask
Rusty Russell98a79d62008-12-13 21:19:41 +10302016 with all 1s, and others with all 0s. When they were centralised,
2017 it was better to provide this option than to break all the archs
Matt LaPlante692105b2009-01-26 11:12:25 +01002018 and have several arch maintainers pursuing me down dark alleys.
Rusty Russell98a79d62008-12-13 21:19:41 +10302019
Jens Axboe3a65dfe2005-11-04 08:43:35 +01002020source "block/Kconfig"
Avi Kivitye98c3202007-10-16 23:27:31 -07002021
2022config PREEMPT_NOTIFIERS
2023 bool
Paul E. McKenneye260be62008-01-25 21:08:24 +01002024
Steffen Klassert16295be2010-01-06 19:47:10 +11002025config PADATA
2026 depends on SMP
2027 bool
2028
Andi Kleen754b7b62012-10-04 17:11:27 -07002029# Can be selected by architectures with broken toolchains
2030# that get confused by correct const<->read_only section
2031# mappings
2032config BROKEN_RODATA
2033 bool
2034
David Howells4520c6a2012-09-21 23:31:13 +01002035config ASN1
2036 tristate
2037 help
2038 Build a simple ASN.1 grammar compiler that produces a bytecode output
2039 that can be interpreted by the ASN.1 stream decoder and used to
2040 inform it as to what tags are to be expected in a stream and what
2041 functions to call on what tags.
2042
Thomas Gleixner6beb0002009-11-09 15:21:34 +00002043source "kernel/Kconfig.locks"