Kconfig 22 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 drivers that have been replaced by something else, and/or are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 AUDIT
  179. bool "Auditing support"
  180. depends on NET
  181. help
  182. Enable auditing infrastructure that can be used with another
  183. kernel subsystem, such as SELinux (which requires this for
  184. logging of avc messages output). Does not do system-call
  185. auditing without CONFIG_AUDITSYSCALL.
  186. config AUDITSYSCALL
  187. bool "Enable system-call auditing support"
  188. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  189. default y if SECURITY_SELINUX
  190. help
  191. Enable low-overhead system-call auditing infrastructure that
  192. can be used independently or with another kernel subsystem,
  193. such as SELinux. To use audit's filesystem watch feature, please
  194. ensure that INOTIFY is configured.
  195. config IKCONFIG
  196. tristate "Kernel .config support"
  197. ---help---
  198. This option enables the complete Linux kernel ".config" file
  199. contents to be saved in the kernel. It provides documentation
  200. of which kernel options are used in a running kernel or in an
  201. on-disk kernel. This information can be extracted from the kernel
  202. image file with the script scripts/extract-ikconfig and used as
  203. input to rebuild the current kernel or to build another kernel.
  204. It can also be extracted from a running kernel by reading
  205. /proc/config.gz if enabled (below).
  206. config IKCONFIG_PROC
  207. bool "Enable access to .config through /proc/config.gz"
  208. depends on IKCONFIG && PROC_FS
  209. ---help---
  210. This option enables access to the kernel configuration file
  211. through /proc/config.gz.
  212. config LOG_BUF_SHIFT
  213. int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  214. range 12 21
  215. default 17 if S390 || LOCKDEP
  216. default 16 if X86_NUMAQ || IA64
  217. default 15 if SMP
  218. default 14
  219. help
  220. Select kernel log buffer size as a power of 2.
  221. Defaults and Examples:
  222. 17 => 128 KB for S/390
  223. 16 => 64 KB for x86 NUMAQ or IA-64
  224. 15 => 32 KB for SMP
  225. 14 => 16 KB for uniprocessor
  226. 13 => 8 KB
  227. 12 => 4 KB
  228. config CPUSETS
  229. bool "Cpuset support"
  230. depends on SMP
  231. help
  232. This option will let you create and manage CPUSETs which
  233. allow dynamically partitioning a system into sets of CPUs and
  234. Memory Nodes and assigning tasks to run only within those sets.
  235. This is primarily useful on large SMP or NUMA systems.
  236. Say N if unsure.
  237. config SYSFS_DEPRECATED
  238. bool "Create deprecated sysfs files"
  239. default y
  240. help
  241. This option creates deprecated symlinks such as the
  242. "device"-link, the <subsystem>:<name>-link, and the
  243. "bus"-link. It may also add deprecated key in the
  244. uevent environment.
  245. None of these features or values should be used today, as
  246. they export driver core implementation details to userspace
  247. or export properties which can't be kept stable across kernel
  248. releases.
  249. If enabled, this option will also move any device structures
  250. that belong to a class, back into the /sys/class hierarchy, in
  251. order to support older versions of udev.
  252. If you are using a distro that was released in 2006 or later,
  253. it should be safe to say N here.
  254. config RELAY
  255. bool "Kernel->user space relay support (formerly relayfs)"
  256. help
  257. This option enables support for relay interface support in
  258. certain file systems (such as debugfs).
  259. It is designed to provide an efficient mechanism for tools and
  260. facilities to relay large amounts of data from kernel space to
  261. user space.
  262. If unsure, say N.
  263. config BLK_DEV_INITRD
  264. bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  265. depends on BROKEN || !FRV
  266. help
  267. The initial RAM filesystem is a ramfs which is loaded by the
  268. boot loader (loadlin or lilo) and that is mounted as root
  269. before the normal boot procedure. It is typically used to
  270. load modules needed to mount the "real" root file system,
  271. etc. See <file:Documentation/initrd.txt> for details.
  272. If RAM disk support (BLK_DEV_RAM) is also included, this
  273. also enables initial RAM disk (initrd) support and adds
  274. 15 Kbytes (more on some other architectures) to the kernel size.
  275. If unsure say Y.
  276. if BLK_DEV_INITRD
  277. source "usr/Kconfig"
  278. endif
  279. config CC_OPTIMIZE_FOR_SIZE
  280. bool "Optimize for size (Look out for broken compilers!)"
  281. default y
  282. depends on ARM || H8300 || EXPERIMENTAL
  283. help
  284. Enabling this option will pass "-Os" instead of "-O2" to gcc
  285. resulting in a smaller kernel.
  286. WARNING: some versions of gcc may generate incorrect code with this
  287. option. If problems are observed, a gcc upgrade may be needed.
  288. If unsure, say N.
  289. config SYSCTL
  290. bool
  291. menuconfig EMBEDDED
  292. bool "Configure standard kernel features (for small systems)"
  293. help
  294. This option allows certain base kernel options and settings
  295. to be disabled or tweaked. This is for specialized
  296. environments which can tolerate a "non-standard" kernel.
  297. Only use this if you really know what you are doing.
  298. config UID16
  299. bool "Enable 16-bit UID system calls" if EMBEDDED
  300. depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  301. default y
  302. help
  303. This enables the legacy 16-bit UID syscall wrappers.
  304. config SYSCTL_SYSCALL
  305. bool "Sysctl syscall support" if EMBEDDED
  306. default y
  307. select SYSCTL
  308. ---help---
  309. sys_sysctl uses binary paths that have been found challenging
  310. to properly maintain and use. The interface in /proc/sys
  311. using paths with ascii names is now the primary path to this
  312. information.
  313. Almost nothing using the binary sysctl interface so if you are
  314. trying to save some space it is probably safe to disable this,
  315. making your kernel marginally smaller.
  316. If unsure say Y here.
  317. config KALLSYMS
  318. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  319. default y
  320. help
  321. Say Y here to let the kernel print out symbolic crash information and
  322. symbolic stack backtraces. This increases the size of the kernel
  323. somewhat, as all symbols have to be loaded into the kernel image.
  324. config KALLSYMS_ALL
  325. bool "Include all symbols in kallsyms"
  326. depends on DEBUG_KERNEL && KALLSYMS
  327. help
  328. Normally kallsyms only contains the symbols of functions, for nicer
  329. OOPS messages. Some debuggers can use kallsyms for other
  330. symbols too: say Y here to include all symbols, if you need them
  331. and you don't care about adding 300k to the size of your kernel.
  332. Say N.
  333. config KALLSYMS_EXTRA_PASS
  334. bool "Do an extra kallsyms pass"
  335. depends on KALLSYMS
  336. help
  337. If kallsyms is not working correctly, the build will fail with
  338. inconsistent kallsyms data. If that occurs, log a bug report and
  339. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  340. Always say N here unless you find a bug in kallsyms, which must be
  341. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  342. you wait for kallsyms to be fixed.
  343. config HOTPLUG
  344. bool "Support for hot-pluggable devices" if EMBEDDED
  345. default y
  346. help
  347. This option is provided for the case where no hotplug or uevent
  348. capabilities is wanted by the kernel. You should only consider
  349. disabling this option for embedded systems that do not use modules, a
  350. dynamic /dev tree, or dynamic device discovery. Just say Y.
  351. config PRINTK
  352. default y
  353. bool "Enable support for printk" if EMBEDDED
  354. help
  355. This option enables normal printk support. Removing it
  356. eliminates most of the message strings from the kernel image
  357. and makes the kernel more or less silent. As this makes it
  358. very difficult to diagnose system problems, saying N here is
  359. strongly discouraged.
  360. config BUG
  361. bool "BUG() support" if EMBEDDED
  362. default y
  363. help
  364. Disabling this option eliminates support for BUG and WARN, reducing
  365. the size of your kernel image and potentially quietly ignoring
  366. numerous fatal conditions. You should only consider disabling this
  367. option for embedded systems with no facilities for reporting errors.
  368. Just say Y.
  369. config ELF_CORE
  370. default y
  371. bool "Enable ELF core dumps" if EMBEDDED
  372. help
  373. Enable support for generating core dumps. Disabling saves about 4k.
  374. config BASE_FULL
  375. default y
  376. bool "Enable full-sized data structures for core" if EMBEDDED
  377. help
  378. Disabling this option reduces the size of miscellaneous core
  379. kernel data structures. This saves memory on small machines,
  380. but may reduce performance.
  381. config FUTEX
  382. bool "Enable futex support" if EMBEDDED
  383. default y
  384. select RT_MUTEXES
  385. help
  386. Disabling this option will cause the kernel to be built without
  387. support for "fast userspace mutexes". The resulting kernel may not
  388. run glibc-based applications correctly.
  389. config ANON_INODES
  390. bool "Enable anonymous inode source" if EMBEDDED
  391. default y
  392. help
  393. Anonymous inode source for pseudo-files like epoll, signalfd,
  394. timerfd and eventfd.
  395. If unsure, say Y.
  396. config EPOLL
  397. bool "Enable eventpoll support" if EMBEDDED
  398. default y
  399. depends on ANON_INODES
  400. help
  401. Disabling this option will cause the kernel to be built without
  402. support for epoll family of system calls.
  403. config SIGNALFD
  404. bool "Enable signalfd() system call" if EMBEDDED
  405. depends on ANON_INODES
  406. default y
  407. help
  408. Enable the signalfd() system call that allows to receive signals
  409. on a file descriptor.
  410. If unsure, say Y.
  411. config TIMERFD
  412. bool "Enable timerfd() system call" if EMBEDDED
  413. depends on ANON_INODES
  414. default y
  415. help
  416. Enable the timerfd() system call that allows to receive timer
  417. events on a file descriptor.
  418. If unsure, say Y.
  419. config EVENTFD
  420. bool "Enable eventfd() system call" if EMBEDDED
  421. depends on ANON_INODES
  422. default y
  423. help
  424. Enable the eventfd() system call that allows to receive both
  425. kernel notification (ie. KAIO) or userspace notifications.
  426. If unsure, say Y.
  427. config SHMEM
  428. bool "Use full shmem filesystem" if EMBEDDED
  429. default y
  430. depends on MMU
  431. help
  432. The shmem is an internal filesystem used to manage shared memory.
  433. It is backed by swap and manages resource limits. It is also exported
  434. to userspace as tmpfs if TMPFS is enabled. Disabling this
  435. option replaces shmem and tmpfs with the much simpler ramfs code,
  436. which may be appropriate on small systems without swap.
  437. config VM_EVENT_COUNTERS
  438. default y
  439. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  440. help
  441. VM event counters are needed for event counts to be shown.
  442. This option allows the disabling of the VM event counters
  443. on EMBEDDED systems. /proc/vmstat will only show page counts
  444. if VM event counters are disabled.
  445. config SLUB_DEBUG
  446. default y
  447. bool "Enable SLUB debugging support" if EMBEDDED
  448. depends on SLUB
  449. help
  450. SLUB has extensive debug support features. Disabling these can
  451. result in significant savings in code size. This also disables
  452. SLUB sysfs support. /sys/slab will not exist and there will be
  453. no support for cache validation etc.
  454. choice
  455. prompt "Choose SLAB allocator"
  456. default SLAB
  457. help
  458. This option allows to select a slab allocator.
  459. config SLAB
  460. bool "SLAB"
  461. help
  462. The regular slab allocator that is established and known to work
  463. well in all environments. It organizes cache hot objects in
  464. per cpu and per node queues. SLAB is the default choice for
  465. a slab allocator.
  466. config SLUB
  467. bool "SLUB (Unqueued Allocator)"
  468. help
  469. SLUB is a slab allocator that minimizes cache line usage
  470. instead of managing queues of cached objects (SLAB approach).
  471. Per cpu caching is realized using slabs of objects instead
  472. of queues of objects. SLUB can use memory efficiently
  473. and has enhanced diagnostics.
  474. config SLOB
  475. depends on EMBEDDED
  476. bool "SLOB (Simple Allocator)"
  477. help
  478. SLOB replaces the SLAB allocator with a drastically simpler
  479. allocator. SLOB is more space efficient than SLAB but does not
  480. scale well (single lock for all operations) and is also highly
  481. susceptible to fragmentation. SLUB can accomplish a higher object
  482. density. It is usually better to use SLUB instead of SLOB.
  483. endchoice
  484. endmenu # General setup
  485. config RT_MUTEXES
  486. boolean
  487. select PLIST
  488. config TINY_SHMEM
  489. default !SHMEM
  490. bool
  491. config BASE_SMALL
  492. int
  493. default 0 if BASE_FULL
  494. default 1 if !BASE_FULL
  495. menuconfig MODULES
  496. bool "Enable loadable module support"
  497. help
  498. Kernel modules are small pieces of compiled code which can
  499. be inserted in the running kernel, rather than being
  500. permanently built into the kernel. You use the "modprobe"
  501. tool to add (and sometimes remove) them. If you say Y here,
  502. many parts of the kernel can be built as modules (by
  503. answering M instead of Y where indicated): this is most
  504. useful for infrequently used options which are not required
  505. for booting. For more information, see the man pages for
  506. modprobe, lsmod, modinfo, insmod and rmmod.
  507. If you say Y here, you will need to run "make
  508. modules_install" to put the modules under /lib/modules/
  509. where modprobe can find them (you may need to be root to do
  510. this).
  511. If unsure, say Y.
  512. config MODULE_UNLOAD
  513. bool "Module unloading"
  514. depends on MODULES
  515. help
  516. Without this option you will not be able to unload any
  517. modules (note that some modules may not be unloadable
  518. anyway), which makes your kernel slightly smaller and
  519. simpler. If unsure, say Y.
  520. config MODULE_FORCE_UNLOAD
  521. bool "Forced module unloading"
  522. depends on MODULE_UNLOAD && EXPERIMENTAL
  523. help
  524. This option allows you to force a module to unload, even if the
  525. kernel believes it is unsafe: the kernel will remove the module
  526. without waiting for anyone to stop using it (using the -f option to
  527. rmmod). This is mainly for kernel developers and desperate users.
  528. If unsure, say N.
  529. config MODVERSIONS
  530. bool "Module versioning support"
  531. depends on MODULES
  532. help
  533. Usually, you have to use modules compiled with your kernel.
  534. Saying Y here makes it sometimes possible to use modules
  535. compiled for different kernels, by adding enough information
  536. to the modules to (hopefully) spot any changes which would
  537. make them incompatible with the kernel you are running. If
  538. unsure, say N.
  539. config MODULE_SRCVERSION_ALL
  540. bool "Source checksum for all modules"
  541. depends on MODULES
  542. help
  543. Modules which contain a MODULE_VERSION get an extra "srcversion"
  544. field inserted into their modinfo section, which contains a
  545. sum of the source files which made it. This helps maintainers
  546. see exactly which source was used to build a module (since
  547. others sometimes change the module source without updating
  548. the version). With this option, such a "srcversion" field
  549. will be created for all modules. If unsure, say N.
  550. config KMOD
  551. bool "Automatic kernel module loading"
  552. depends on MODULES
  553. help
  554. Normally when you have selected some parts of the kernel to
  555. be created as kernel modules, you must load them (using the
  556. "modprobe" command) before you can use them. If you say Y
  557. here, some parts of the kernel will be able to load modules
  558. automatically: when a part of the kernel needs a module, it
  559. runs modprobe with the appropriate arguments, thereby
  560. loading the module if it is available. If unsure, say Y.
  561. config STOP_MACHINE
  562. bool
  563. default y
  564. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  565. help
  566. Need stop_machine() primitive.
  567. source "block/Kconfig"