Kconfig 23 KB

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 drivers that have been replaced by something else, and/or are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