| blob | 96b54595f1dc16e1809852ca0462184b948b54b4 |
1 config DEFCONFIG_LIST
2 string
3 depends on !UML
4 option defconfig_list
5 default "/lib/modules/$UNAME_RELEASE/.config"
6 default "/etc/kernel-config"
7 default "/boot/config-$UNAME_RELEASE"
8 default "arch/$ARCH/defconfig"
10 menu "General setup"
12 config EXPERIMENTAL
13 bool "Prompt for development and/or incomplete code/drivers"
14 ---help---
15 Some of the various things that Linux supports (such as network
16 drivers, file systems, network protocols, etc.) can be in a state
17 of development where the functionality, stability, or the level of
18 testing is not yet high enough for general use. This is usually
19 known as the "alpha-test" phase among developers. If a feature is
20 currently in alpha-test, then the developers usually discourage
21 uninformed widespread use of this feature by the general public to
22 avoid "Why doesn't this work?" type mail messages. However, active
23 testing and use of these systems is welcomed. Just be aware that it
24 may not meet the normal level of reliability or it may fail to work
25 in some special cases. Detailed bug reports from people familiar
26 with the kernel internals are usually welcomed by the developers
27 (before submitting bug reports, please read the documents
28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
29 <file:Documentation/BUG-HUNTING>, and
30 <file:Documentation/oops-tracing.txt> in the kernel source).
32 This option will also make obsoleted drivers available. These are
33 drivers that have been replaced by something else, and/or are
34 scheduled to be removed in a future kernel release.
36 Unless you intend to help test and develop a feature or driver that
37 falls into this category, or you have a situation that requires
38 using these features, you should probably say N here, which will
39 cause the configurator to present you with fewer choices. If
40 you say Y here, you will be offered the choice of using features or
41 drivers that are currently considered to be in the alpha-test phase.
43 config BROKEN
44 bool
46 config BROKEN_ON_SMP
47 bool
48 depends on BROKEN || !SMP
49 default y
51 config LOCK_KERNEL
52 bool
53 depends on SMP || PREEMPT
54 default y
56 config INIT_ENV_ARG_LIMIT
57 int
58 default 32 if !UML
59 default 128 if UML
60 help
61 Maximum of each of the number of arguments and environment
62 variables passed to init from the kernel command line.
65 config LOCALVERSION
66 string "Local version - append to kernel release"
67 help
68 Append an extra string to the end of your kernel version.
69 This will show up when you type uname, for example.
70 The string you set here will be appended after the contents of
71 any files with a filename matching localversion* in your
72 object and source tree, in that order. Your total string can
73 be a maximum of 64 characters.
75 config LOCALVERSION_AUTO
76 bool "Automatically append version information to the version string"
77 default y
78 help
79 This will try to automatically determine if the current tree is a
80 release tree by looking for git tags that belong to the current
81 top of tree revision.
83 A string of the format -gxxxxxxxx will be added to the localversion
84 if a git-based tree is found. The string generated by this will be
85 appended after any matching localversion* files, and after the value
86 set in CONFIG_LOCALVERSION.
88 (The actual string used here is the first eight characters produced
89 by running the command:
91 $ git rev-parse --verify HEAD
93 which is done within the script "scripts/setlocalversion".)
95 config SWAP
96 bool "Support for paging of anonymous memory (swap)"
97 depends on MMU && BLOCK
98 default y
99 help
100 This option allows you to choose whether you want to have support
101 for so called swap devices or swap files in your kernel that are
102 used to provide more virtual memory than the actual RAM present
103 in your computer. If unsure say Y.
105 config SYSVIPC
106 bool "System V IPC"
107 ---help---
108 Inter Process Communication is a suite of library functions and
109 system calls which let processes (running programs) synchronize and
110 exchange information. It is generally considered to be a good thing,
111 and some programs won't run unless you say Y here. In particular, if
112 you want to run the DOS emulator dosemu under Linux (read the
113 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
114 you'll need to say Y here.
116 You can find documentation about IPC with "info ipc" and also in
117 section 6.4 of the Linux Programmer's Guide, available from
118 <http://www.tldp.org/guides.html>.
120 config SYSVIPC_SYSCTL
121 bool
122 depends on SYSVIPC
123 depends on SYSCTL
124 default y
126 config POSIX_MQUEUE
127 bool "POSIX Message Queues"
128 depends on NET && EXPERIMENTAL
129 ---help---
130 POSIX variant of message queues is a part of IPC. In POSIX message
131 queues every message has a priority which decides about succession
132 of receiving it by a process. If you want to compile and run
133 programs written e.g. for Solaris with use of its POSIX message
134 queues (functions mq_*) say Y here.
136 POSIX message queues are visible as a filesystem called 'mqueue'
137 and can be mounted somewhere if you want to do filesystem
138 operations on message queues.
140 If unsure, say Y.
142 config BSD_PROCESS_ACCT
143 bool "BSD Process Accounting"
144 help
145 If you say Y here, a user level program will be able to instruct the
146 kernel (via a special system call) to write process accounting
147 information to a file: whenever a process exits, information about
148 that process will be appended to the file by the kernel. The
149 information includes things such as creation time, owning user,
150 command name, memory usage, controlling terminal etc. (the complete
151 list is in the struct acct in <file:include/linux/acct.h>). It is
152 up to the user level program to do useful things with this
153 information. This is generally a good idea, so say Y.
155 config BSD_PROCESS_ACCT_V3
156 bool "BSD Process Accounting version 3 file format"
157 depends on BSD_PROCESS_ACCT
158 default n
159 help
160 If you say Y here, the process accounting information is written
161 in a new file format that also logs the process IDs of each
162 process and it's parent. Note that this file format is incompatible
163 with previous v0/v1/v2 file formats, so you will need updated tools
164 for processing it. A preliminary version of these tools is available
165 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
167 config TASKSTATS
168 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
169 depends on NET
170 default n
171 help
172 Export selected statistics for tasks/processes through the
173 generic netlink interface. Unlike BSD process accounting, the
174 statistics are available during the lifetime of tasks/processes as
175 responses to commands. Like BSD accounting, they are sent to user
176 space on task exit.
178 Say N if unsure.
180 config TASK_DELAY_ACCT
181 bool "Enable per-task delay accounting (EXPERIMENTAL)"
182 depends on TASKSTATS
183 help
184 Collect information on time spent by a task waiting for system
185 resources like cpu, synchronous block I/O completion and swapping
186 in pages. Such statistics can help in setting a task's priorities
187 relative to other tasks for cpu, io, rss limits etc.
189 Say N if unsure.
191 config TASK_XACCT
192 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
193 depends on TASKSTATS
194 help
195 Collect extended task accounting data and send the data
196 to userland for processing over the taskstats interface.
198 Say N if unsure.
200 config TASK_IO_ACCOUNTING
201 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
202 depends on TASK_XACCT
203 help
204 Collect information on the number of bytes of storage I/O which this
205 task has caused.
207 Say N if unsure.
209 config USER_NS
210 bool "User Namespaces (EXPERIMENTAL)"
211 default n
212 depends on EXPERIMENTAL
213 help
214 Support user namespaces. This allows containers, i.e.
215 vservers, to use user namespaces to provide different
216 user info for different servers. If unsure, say N.
218 config AUDIT
219 bool "Auditing support"
220 depends on NET
221 help
222 Enable auditing infrastructure that can be used with another
223 kernel subsystem, such as SELinux (which requires this for
224 logging of avc messages output). Does not do system-call
225 auditing without CONFIG_AUDITSYSCALL.
227 config AUDITSYSCALL
228 bool "Enable system-call auditing support"
229 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
230 default y if SECURITY_SELINUX
231 help
232 Enable low-overhead system-call auditing infrastructure that
233 can be used independently or with another kernel subsystem,
234 such as SELinux. To use audit's filesystem watch feature, please
235 ensure that INOTIFY is configured.
237 config IKCONFIG
238 tristate "Kernel .config support"
239 ---help---
240 This option enables the complete Linux kernel ".config" file
241 contents to be saved in the kernel. It provides documentation
242 of which kernel options are used in a running kernel or in an
243 on-disk kernel. This information can be extracted from the kernel
244 image file with the script scripts/extract-ikconfig and used as
245 input to rebuild the current kernel or to build another kernel.
246 It can also be extracted from a running kernel by reading
247 /proc/config.gz if enabled (below).
249 config IKCONFIG_PROC
250 bool "Enable access to .config through /proc/config.gz"
251 depends on IKCONFIG && PROC_FS
252 ---help---
253 This option enables access to the kernel configuration file
254 through /proc/config.gz.
256 config LOG_BUF_SHIFT
257 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
258 range 12 21
259 default 17 if S390 || LOCKDEP
260 default 16 if X86_NUMAQ || IA64
261 default 15 if SMP
262 default 14
263 help
264 Select kernel log buffer size as a power of 2.
265 Defaults and Examples:
266 17 => 128 KB for S/390
267 16 => 64 KB for x86 NUMAQ or IA-64
268 15 => 32 KB for SMP
269 14 => 16 KB for uniprocessor
270 13 => 8 KB
271 12 => 4 KB
273 config CPUSETS
274 bool "Cpuset support"
275 depends on SMP
276 help
277 This option will let you create and manage CPUSETs which
278 allow dynamically partitioning a system into sets of CPUs and
279 Memory Nodes and assigning tasks to run only within those sets.
280 This is primarily useful on large SMP or NUMA systems.
282 Say N if unsure.
284 config SYSFS_DEPRECATED
285 bool "Create deprecated sysfs files"
286 default y
287 help
288 This option creates deprecated symlinks such as the
289 "device"-link, the <subsystem>:<name>-link, and the
290 "bus"-link. It may also add deprecated key in the
291 uevent environment.
292 None of these features or values should be used today, as
293 they export driver core implementation details to userspace
294 or export properties which can't be kept stable across kernel
295 releases.
297 If enabled, this option will also move any device structures
298 that belong to a class, back into the /sys/class hierarchy, in
299 order to support older versions of udev.
301 If you are using a distro that was released in 2006 or later,
302 it should be safe to say N here.
304 config RELAY
305 bool "Kernel->user space relay support (formerly relayfs)"
306 help
307 This option enables support for relay interface support in
308 certain file systems (such as debugfs).
309 It is designed to provide an efficient mechanism for tools and
310 facilities to relay large amounts of data from kernel space to
311 user space.
313 If unsure, say N.
315 config BLK_DEV_INITRD
316 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
317 depends on BROKEN || !FRV
318 help
319 The initial RAM filesystem is a ramfs which is loaded by the
320 boot loader (loadlin or lilo) and that is mounted as root
321 before the normal boot procedure. It is typically used to
322 load modules needed to mount the "real" root file system,
323 etc. See <file:Documentation/initrd.txt> for details.
325 If RAM disk support (BLK_DEV_RAM) is also included, this
326 also enables initial RAM disk (initrd) support and adds
327 15 Kbytes (more on some other architectures) to the kernel size.
329 If unsure say Y.
331 if BLK_DEV_INITRD
333 source "usr/Kconfig"
335 endif
337 config CC_OPTIMIZE_FOR_SIZE
338 bool "Optimize for size (Look out for broken compilers!)"
339 default y
340 depends on ARM || H8300 || SUPERH || EXPERIMENTAL
341 help
342 Enabling this option will pass "-Os" instead of "-O2" to gcc
343 resulting in a smaller kernel.
345 WARNING: some versions of gcc may generate incorrect code with this
346 option. If problems are observed, a gcc upgrade may be needed.
348 If unsure, say N.
350 config SYSCTL
351 bool
353 menuconfig EMBEDDED
354 bool "Configure standard kernel features (for small systems)"
355 help
356 This option allows certain base kernel options and settings
357 to be disabled or tweaked. This is for specialized
358 environments which can tolerate a "non-standard" kernel.
359 Only use this if you really know what you are doing.
361 config UID16
362 bool "Enable 16-bit UID system calls" if EMBEDDED
363 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
364 default y
365 help
366 This enables the legacy 16-bit UID syscall wrappers.
368 config SYSCTL_SYSCALL
369 bool "Sysctl syscall support" if EMBEDDED
370 default y
371 select SYSCTL
372 ---help---
373 sys_sysctl uses binary paths that have been found challenging
374 to properly maintain and use. The interface in /proc/sys
375 using paths with ascii names is now the primary path to this
376 information.
378 Almost nothing using the binary sysctl interface so if you are
379 trying to save some space it is probably safe to disable this,
380 making your kernel marginally smaller.
382 If unsure say Y here.
384 config KALLSYMS
385 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
386 default y
387 help
388 Say Y here to let the kernel print out symbolic crash information and
389 symbolic stack backtraces. This increases the size of the kernel
390 somewhat, as all symbols have to be loaded into the kernel image.
392 config KALLSYMS_ALL
393 bool "Include all symbols in kallsyms"
394 depends on DEBUG_KERNEL && KALLSYMS
395 help
396 Normally kallsyms only contains the symbols of functions, for nicer
397 OOPS messages. Some debuggers can use kallsyms for other
398 symbols too: say Y here to include all symbols, if you need them
399 and you don't care about adding 300k to the size of your kernel.
401 Say N.
403 config KALLSYMS_EXTRA_PASS
404 bool "Do an extra kallsyms pass"
405 depends on KALLSYMS
406 help
407 If kallsyms is not working correctly, the build will fail with
408 inconsistent kallsyms data. If that occurs, log a bug report and
409 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
410 Always say N here unless you find a bug in kallsyms, which must be
411 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
412 you wait for kallsyms to be fixed.
415 config HOTPLUG
416 bool "Support for hot-pluggable devices" if EMBEDDED
417 default y
418 help
419 This option is provided for the case where no hotplug or uevent
420 capabilities is wanted by the kernel. You should only consider
421 disabling this option for embedded systems that do not use modules, a
422 dynamic /dev tree, or dynamic device discovery. Just say Y.
424 config PRINTK
425 default y
426 bool "Enable support for printk" if EMBEDDED
427 help
428 This option enables normal printk support. Removing it
429 eliminates most of the message strings from the kernel image
430 and makes the kernel more or less silent. As this makes it
431 very difficult to diagnose system problems, saying N here is
432 strongly discouraged.
434 config BUG
435 bool "BUG() support" if EMBEDDED
436 default y
437 help
438 Disabling this option eliminates support for BUG and WARN, reducing
439 the size of your kernel image and potentially quietly ignoring
440 numerous fatal conditions. You should only consider disabling this
441 option for embedded systems with no facilities for reporting errors.
442 Just say Y.
444 config ELF_CORE
445 default y
446 bool "Enable ELF core dumps" if EMBEDDED
447 help
448 Enable support for generating core dumps. Disabling saves about 4k.
450 config BASE_FULL
451 default y
452 bool "Enable full-sized data structures for core" if EMBEDDED
453 help
454 Disabling this option reduces the size of miscellaneous core
455 kernel data structures. This saves memory on small machines,
456 but may reduce performance.
458 config FUTEX
459 bool "Enable futex support" if EMBEDDED
460 default y
461 select RT_MUTEXES
462 help
463 Disabling this option will cause the kernel to be built without
464 support for "fast userspace mutexes". The resulting kernel may not
465 run glibc-based applications correctly.
467 config ANON_INODES
468 bool
470 config EPOLL
471 bool "Enable eventpoll support" if EMBEDDED
472 default y
473 select ANON_INODES
474 help
475 Disabling this option will cause the kernel to be built without
476 support for epoll family of system calls.
478 config SIGNALFD
479 bool "Enable signalfd() system call" if EMBEDDED
480 select ANON_INODES
481 default y
482 help
483 Enable the signalfd() system call that allows to receive signals
484 on a file descriptor.
486 If unsure, say Y.
488 config TIMERFD
489 bool "Enable timerfd() system call" if EMBEDDED
490 select ANON_INODES
491 default y
492 help
493 Enable the timerfd() system call that allows to receive timer
494 events on a file descriptor.
496 If unsure, say Y.
498 config EVENTFD
499 bool "Enable eventfd() system call" if EMBEDDED
500 select ANON_INODES
501 default y
502 help
503 Enable the eventfd() system call that allows to receive both
504 kernel notification (ie. KAIO) or userspace notifications.
506 If unsure, say Y.
508 config SHMEM
509 bool "Use full shmem filesystem" if EMBEDDED
510 default y
511 depends on MMU
512 help
513 The shmem is an internal filesystem used to manage shared memory.
514 It is backed by swap and manages resource limits. It is also exported
515 to userspace as tmpfs if TMPFS is enabled. Disabling this
516 option replaces shmem and tmpfs with the much simpler ramfs code,
517 which may be appropriate on small systems without swap.
519 config VM_EVENT_COUNTERS
520 default y
521 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
522 help
523 VM event counters are needed for event counts to be shown.
524 This option allows the disabling of the VM event counters
525 on EMBEDDED systems. /proc/vmstat will only show page counts
526 if VM event counters are disabled.
528 config SLUB_DEBUG
529 default y
530 bool "Enable SLUB debugging support" if EMBEDDED
531 depends on SLUB
532 help
533 SLUB has extensive debug support features. Disabling these can
534 result in significant savings in code size. This also disables
535 SLUB sysfs support. /sys/slab will not exist and there will be
536 no support for cache validation etc.
538 choice
539 prompt "Choose SLAB allocator"
540 default SLUB
541 help
542 This option allows to select a slab allocator.
544 config SLAB
545 bool "SLAB"
546 help
547 The regular slab allocator that is established and known to work
548 well in all environments. It organizes cache hot objects in
549 per cpu and per node queues. SLAB is the default choice for
550 a slab allocator.
552 config SLUB
553 bool "SLUB (Unqueued Allocator)"
554 help
555 SLUB is a slab allocator that minimizes cache line usage
556 instead of managing queues of cached objects (SLAB approach).
557 Per cpu caching is realized using slabs of objects instead
558 of queues of objects. SLUB can use memory efficiently
559 and has enhanced diagnostics.
561 config SLOB
562 depends on EMBEDDED
563 bool "SLOB (Simple Allocator)"
564 help
565 SLOB replaces the SLAB allocator with a drastically simpler
566 allocator. SLOB is more space efficient than SLAB but does not
567 scale well (single lock for all operations) and is also highly
568 susceptible to fragmentation. SLUB can accomplish a higher object
569 density. It is usually better to use SLUB instead of SLOB.
571 endchoice
573 endmenu # General setup
575 config RT_MUTEXES
576 boolean
577 select PLIST
579 config TINY_SHMEM
580 default !SHMEM
581 bool
583 config BASE_SMALL
584 int
585 default 0 if BASE_FULL
586 default 1 if !BASE_FULL
588 menuconfig MODULES
589 bool "Enable loadable module support"
590 help
591 Kernel modules are small pieces of compiled code which can
592 be inserted in the running kernel, rather than being
593 permanently built into the kernel. You use the "modprobe"
594 tool to add (and sometimes remove) them. If you say Y here,
595 many parts of the kernel can be built as modules (by
596 answering M instead of Y where indicated): this is most
597 useful for infrequently used options which are not required
598 for booting. For more information, see the man pages for
599 modprobe, lsmod, modinfo, insmod and rmmod.
601 If you say Y here, you will need to run "make
602 modules_install" to put the modules under /lib/modules/
603 where modprobe can find them (you may need to be root to do
604 this).
606 If unsure, say Y.
608 config MODULE_UNLOAD
609 bool "Module unloading"
610 depends on MODULES
611 help
612 Without this option you will not be able to unload any
613 modules (note that some modules may not be unloadable
614 anyway), which makes your kernel slightly smaller and
615 simpler. If unsure, say Y.
617 config MODULE_FORCE_UNLOAD
618 bool "Forced module unloading"
619 depends on MODULE_UNLOAD && EXPERIMENTAL
620 help
621 This option allows you to force a module to unload, even if the
622 kernel believes it is unsafe: the kernel will remove the module
623 without waiting for anyone to stop using it (using the -f option to
624 rmmod). This is mainly for kernel developers and desperate users.
625 If unsure, say N.
627 config MODVERSIONS
628 bool "Module versioning support"
629 depends on MODULES
630 help
631 Usually, you have to use modules compiled with your kernel.
632 Saying Y here makes it sometimes possible to use modules
633 compiled for different kernels, by adding enough information
634 to the modules to (hopefully) spot any changes which would
635 make them incompatible with the kernel you are running. If
636 unsure, say N.
638 config MODULE_SRCVERSION_ALL
639 bool "Source checksum for all modules"
640 depends on MODULES
641 help
642 Modules which contain a MODULE_VERSION get an extra "srcversion"
643 field inserted into their modinfo section, which contains a
644 sum of the source files which made it. This helps maintainers
645 see exactly which source was used to build a module (since
646 others sometimes change the module source without updating
647 the version). With this option, such a "srcversion" field
648 will be created for all modules. If unsure, say N.
650 config KMOD
651 bool "Automatic kernel module loading"
652 depends on MODULES
653 help
654 Normally when you have selected some parts of the kernel to
655 be created as kernel modules, you must load them (using the
656 "modprobe" command) before you can use them. If you say Y
657 here, some parts of the kernel will be able to load modules
658 automatically: when a part of the kernel needs a module, it
659 runs modprobe with the appropriate arguments, thereby
660 loading the module if it is available. If unsure, say Y.
662 config STOP_MACHINE
663 bool
664 default y
665 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
666 help
667 Need stop_machine() primitive.
669 source "block/Kconfig"