Kconfig 20 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 drivers that have been replaced by something else, and/or are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
  72. belong to the current 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. Note: This requires Perl, and a git repository, but not necessarily
  78. the git or cogito tools to be installed.
  79. config SWAP
  80. bool "Support for paging of anonymous memory (swap)"
  81. depends on MMU && BLOCK
  82. default y
  83. help
  84. This option allows you to choose whether you want to have support
  85. for so called swap devices or swap files in your kernel that are
  86. used to provide more virtual memory than the actual RAM present
  87. in your computer. If unsure say Y.
  88. config SYSVIPC
  89. bool "System V IPC"
  90. ---help---
  91. Inter Process Communication is a suite of library functions and
  92. system calls which let processes (running programs) synchronize and
  93. exchange information. It is generally considered to be a good thing,
  94. and some programs won't run unless you say Y here. In particular, if
  95. you want to run the DOS emulator dosemu under Linux (read the
  96. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  97. you'll need to say Y here.
  98. You can find documentation about IPC with "info ipc" and also in
  99. section 6.4 of the Linux Programmer's Guide, available from
  100. <http://www.tldp.org/guides.html>.
  101. config IPC_NS
  102. bool "IPC Namespaces"
  103. depends on SYSVIPC
  104. default n
  105. help
  106. Support ipc namespaces. This allows containers, i.e. virtual
  107. environments, to use ipc namespaces to provide different ipc
  108. objects for different servers. If unsure, say N.
  109. config POSIX_MQUEUE
  110. bool "POSIX Message Queues"
  111. depends on NET && EXPERIMENTAL
  112. ---help---
  113. POSIX variant of message queues is a part of IPC. In POSIX message
  114. queues every message has a priority which decides about succession
  115. of receiving it by a process. If you want to compile and run
  116. programs written e.g. for Solaris with use of its POSIX message
  117. queues (functions mq_*) say Y here. To use this feature you will
  118. also need mqueue library, available from
  119. <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
  120. POSIX message queues are visible as a filesystem called 'mqueue'
  121. and can be mounted somewhere if you want to do filesystem
  122. operations on message queues.
  123. If unsure, say Y.
  124. config BSD_PROCESS_ACCT
  125. bool "BSD Process Accounting"
  126. help
  127. If you say Y here, a user level program will be able to instruct the
  128. kernel (via a special system call) to write process accounting
  129. information to a file: whenever a process exits, information about
  130. that process will be appended to the file by the kernel. The
  131. information includes things such as creation time, owning user,
  132. command name, memory usage, controlling terminal etc. (the complete
  133. list is in the struct acct in <file:include/linux/acct.h>). It is
  134. up to the user level program to do useful things with this
  135. information. This is generally a good idea, so say Y.
  136. config BSD_PROCESS_ACCT_V3
  137. bool "BSD Process Accounting version 3 file format"
  138. depends on BSD_PROCESS_ACCT
  139. default n
  140. help
  141. If you say Y here, the process accounting information is written
  142. in a new file format that also logs the process IDs of each
  143. process and it's parent. Note that this file format is incompatible
  144. with previous v0/v1/v2 file formats, so you will need updated tools
  145. for processing it. A preliminary version of these tools is available
  146. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  147. config TASKSTATS
  148. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  149. depends on NET
  150. default n
  151. help
  152. Export selected statistics for tasks/processes through the
  153. generic netlink interface. Unlike BSD process accounting, the
  154. statistics are available during the lifetime of tasks/processes as
  155. responses to commands. Like BSD accounting, they are sent to user
  156. space on task exit.
  157. Say N if unsure.
  158. config TASK_DELAY_ACCT
  159. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  160. depends on TASKSTATS
  161. help
  162. Collect information on time spent by a task waiting for system
  163. resources like cpu, synchronous block I/O completion and swapping
  164. in pages. Such statistics can help in setting a task's priorities
  165. relative to other tasks for cpu, io, rss limits etc.
  166. Say N if unsure.
  167. config UTS_NS
  168. bool "UTS Namespaces"
  169. default n
  170. help
  171. Support uts namespaces. This allows containers, i.e.
  172. vservers, to use uts namespaces to provide different
  173. uts info for different servers. If unsure, say N.
  174. config AUDIT
  175. bool "Auditing support"
  176. depends on NET
  177. help
  178. Enable auditing infrastructure that can be used with another
  179. kernel subsystem, such as SELinux (which requires this for
  180. logging of avc messages output). Does not do system-call
  181. auditing without CONFIG_AUDITSYSCALL.
  182. config AUDITSYSCALL
  183. bool "Enable system-call auditing support"
  184. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  185. default y if SECURITY_SELINUX
  186. help
  187. Enable low-overhead system-call auditing infrastructure that
  188. can be used independently or with another kernel subsystem,
  189. such as SELinux. To use audit's filesystem watch feature, please
  190. ensure that INOTIFY is configured.
  191. config IKCONFIG
  192. tristate "Kernel .config support"
  193. ---help---
  194. This option enables the complete Linux kernel ".config" file
  195. contents to be saved in the kernel. It provides documentation
  196. of which kernel options are used in a running kernel or in an
  197. on-disk kernel. This information can be extracted from the kernel
  198. image file with the script scripts/extract-ikconfig and used as
  199. input to rebuild the current kernel or to build another kernel.
  200. It can also be extracted from a running kernel by reading
  201. /proc/config.gz if enabled (below).
  202. config IKCONFIG_PROC
  203. bool "Enable access to .config through /proc/config.gz"
  204. depends on IKCONFIG && PROC_FS
  205. ---help---
  206. This option enables access to the kernel configuration file
  207. through /proc/config.gz.
  208. config CPUSETS
  209. bool "Cpuset support"
  210. depends on SMP
  211. help
  212. This option will let you create and manage CPUSETs which
  213. allow dynamically partitioning a system into sets of CPUs and
  214. Memory Nodes and assigning tasks to run only within those sets.
  215. This is primarily useful on large SMP or NUMA systems.
  216. Say N if unsure.
  217. config SYSFS_DEPRECATED
  218. bool "Create deprecated sysfs files"
  219. default y
  220. help
  221. This option creates deprecated symlinks such as the
  222. "device"-link, the <subsystem>:<name>-link, and the
  223. "bus"-link. It may also add deprecated key in the
  224. uevent environment.
  225. None of these features or values should be used today, as
  226. they export driver core implementation details to userspace
  227. or export properties which can't be kept stable across kernel
  228. releases.
  229. If enabled, this option will also move any device structures
  230. that belong to a class, back into the /sys/class heirachy, in
  231. order to support older versions of udev.
  232. If you are using a distro that was released in 2006 or later,
  233. it should be safe to say N here.
  234. config RELAY
  235. bool "Kernel->user space relay support (formerly relayfs)"
  236. help
  237. This option enables support for relay interface support in
  238. certain file systems (such as debugfs).
  239. It is designed to provide an efficient mechanism for tools and
  240. facilities to relay large amounts of data from kernel space to
  241. user space.
  242. If unsure, say N.
  243. source "usr/Kconfig"
  244. config CC_OPTIMIZE_FOR_SIZE
  245. bool "Optimize for size (Look out for broken compilers!)"
  246. default y
  247. depends on ARM || H8300 || EXPERIMENTAL
  248. help
  249. Enabling this option will pass "-Os" instead of "-O2" to gcc
  250. resulting in a smaller kernel.
  251. WARNING: some versions of gcc may generate incorrect code with this
  252. option. If problems are observed, a gcc upgrade may be needed.
  253. If unsure, say N.
  254. config TASK_XACCT
  255. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  256. depends on TASKSTATS
  257. help
  258. Collect extended task accounting data and send the data
  259. to userland for processing over the taskstats interface.
  260. Say N if unsure.
  261. config SYSCTL
  262. bool
  263. menuconfig EMBEDDED
  264. bool "Configure standard kernel features (for small systems)"
  265. help
  266. This option allows certain base kernel options and settings
  267. to be disabled or tweaked. This is for specialized
  268. environments which can tolerate a "non-standard" kernel.
  269. Only use this if you really know what you are doing.
  270. config UID16
  271. bool "Enable 16-bit UID system calls" if EMBEDDED
  272. depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  273. default y
  274. help
  275. This enables the legacy 16-bit UID syscall wrappers.
  276. config SYSCTL_SYSCALL
  277. bool "Sysctl syscall support" if EMBEDDED
  278. default y
  279. select SYSCTL
  280. ---help---
  281. sys_sysctl uses binary paths that have been found challenging
  282. to properly maintain and use. The interface in /proc/sys
  283. using paths with ascii names is now the primary path to this
  284. information.
  285. Almost nothing using the binary sysctl interface so if you are
  286. trying to save some space it is probably safe to disable this,
  287. making your kernel marginally smaller.
  288. If unsure say Y here.
  289. config KALLSYMS
  290. bool "Load all symbols for debugging/kksymoops" if EMBEDDED
  291. default y
  292. help
  293. Say Y here to let the kernel print out symbolic crash information and
  294. symbolic stack backtraces. This increases the size of the kernel
  295. somewhat, as all symbols have to be loaded into the kernel image.
  296. config KALLSYMS_ALL
  297. bool "Include all symbols in kallsyms"
  298. depends on DEBUG_KERNEL && KALLSYMS
  299. help
  300. Normally kallsyms only contains the symbols of functions, for nicer
  301. OOPS messages. Some debuggers can use kallsyms for other
  302. symbols too: say Y here to include all symbols, if you need them
  303. and you don't care about adding 300k to the size of your kernel.
  304. Say N.
  305. config KALLSYMS_EXTRA_PASS
  306. bool "Do an extra kallsyms pass"
  307. depends on KALLSYMS
  308. help
  309. If kallsyms is not working correctly, the build will fail with
  310. inconsistent kallsyms data. If that occurs, log a bug report and
  311. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  312. Always say N here unless you find a bug in kallsyms, which must be
  313. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  314. you wait for kallsyms to be fixed.
  315. config HOTPLUG
  316. bool "Support for hot-pluggable devices" if EMBEDDED
  317. default y
  318. help
  319. This option is provided for the case where no hotplug or uevent
  320. capabilities is wanted by the kernel. You should only consider
  321. disabling this option for embedded systems that do not use modules, a
  322. dynamic /dev tree, or dynamic device discovery. Just say Y.
  323. config PRINTK
  324. default y
  325. bool "Enable support for printk" if EMBEDDED
  326. help
  327. This option enables normal printk support. Removing it
  328. eliminates most of the message strings from the kernel image
  329. and makes the kernel more or less silent. As this makes it
  330. very difficult to diagnose system problems, saying N here is
  331. strongly discouraged.
  332. config BUG
  333. bool "BUG() support" if EMBEDDED
  334. default y
  335. help
  336. Disabling this option eliminates support for BUG and WARN, reducing
  337. the size of your kernel image and potentially quietly ignoring
  338. numerous fatal conditions. You should only consider disabling this
  339. option for embedded systems with no facilities for reporting errors.
  340. Just say Y.
  341. config ELF_CORE
  342. default y
  343. bool "Enable ELF core dumps" if EMBEDDED
  344. help
  345. Enable support for generating core dumps. Disabling saves about 4k.
  346. config BASE_FULL
  347. default y
  348. bool "Enable full-sized data structures for core" if EMBEDDED
  349. help
  350. Disabling this option reduces the size of miscellaneous core
  351. kernel data structures. This saves memory on small machines,
  352. but may reduce performance.
  353. config FUTEX
  354. bool "Enable futex support" if EMBEDDED
  355. default y
  356. select RT_MUTEXES
  357. help
  358. Disabling this option will cause the kernel to be built without
  359. support for "fast userspace mutexes". The resulting kernel may not
  360. run glibc-based applications correctly.
  361. config EPOLL
  362. bool "Enable eventpoll support" if EMBEDDED
  363. default y
  364. help
  365. Disabling this option will cause the kernel to be built without
  366. support for epoll family of system calls.
  367. config SHMEM
  368. bool "Use full shmem filesystem" if EMBEDDED
  369. default y
  370. depends on MMU
  371. help
  372. The shmem is an internal filesystem used to manage shared memory.
  373. It is backed by swap and manages resource limits. It is also exported
  374. to userspace as tmpfs if TMPFS is enabled. Disabling this
  375. option replaces shmem and tmpfs with the much simpler ramfs code,
  376. which may be appropriate on small systems without swap.
  377. config SLAB
  378. default y
  379. bool "Use full SLAB allocator" if EMBEDDED
  380. help
  381. Disabling this replaces the advanced SLAB allocator and
  382. kmalloc support with the drastically simpler SLOB allocator.
  383. SLOB is more space efficient but does not scale well and is
  384. more susceptible to fragmentation.
  385. config VM_EVENT_COUNTERS
  386. default y
  387. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  388. help
  389. VM event counters are only needed to for event counts to be
  390. shown. They have no function for the kernel itself. This
  391. option allows the disabling of the VM event counters.
  392. /proc/vmstat will only show page counts.
  393. endmenu # General setup
  394. config RT_MUTEXES
  395. boolean
  396. select PLIST
  397. config TINY_SHMEM
  398. default !SHMEM
  399. bool
  400. config BASE_SMALL
  401. int
  402. default 0 if BASE_FULL
  403. default 1 if !BASE_FULL
  404. config SLOB
  405. default !SLAB
  406. bool
  407. menu "Loadable module support"
  408. config MODULES
  409. bool "Enable loadable module support"
  410. help
  411. Kernel modules are small pieces of compiled code which can
  412. be inserted in the running kernel, rather than being
  413. permanently built into the kernel. You use the "modprobe"
  414. tool to add (and sometimes remove) them. If you say Y here,
  415. many parts of the kernel can be built as modules (by
  416. answering M instead of Y where indicated): this is most
  417. useful for infrequently used options which are not required
  418. for booting. For more information, see the man pages for
  419. modprobe, lsmod, modinfo, insmod and rmmod.
  420. If you say Y here, you will need to run "make
  421. modules_install" to put the modules under /lib/modules/
  422. where modprobe can find them (you may need to be root to do
  423. this).
  424. If unsure, say Y.
  425. config MODULE_UNLOAD
  426. bool "Module unloading"
  427. depends on MODULES
  428. help
  429. Without this option you will not be able to unload any
  430. modules (note that some modules may not be unloadable
  431. anyway), which makes your kernel slightly smaller and
  432. simpler. If unsure, say Y.
  433. config MODULE_FORCE_UNLOAD
  434. bool "Forced module unloading"
  435. depends on MODULE_UNLOAD && EXPERIMENTAL
  436. help
  437. This option allows you to force a module to unload, even if the
  438. kernel believes it is unsafe: the kernel will remove the module
  439. without waiting for anyone to stop using it (using the -f option to
  440. rmmod). This is mainly for kernel developers and desperate users.
  441. If unsure, say N.
  442. config MODVERSIONS
  443. bool "Module versioning support"
  444. depends on MODULES
  445. help
  446. Usually, you have to use modules compiled with your kernel.
  447. Saying Y here makes it sometimes possible to use modules
  448. compiled for different kernels, by adding enough information
  449. to the modules to (hopefully) spot any changes which would
  450. make them incompatible with the kernel you are running. If
  451. unsure, say N.
  452. config MODULE_SRCVERSION_ALL
  453. bool "Source checksum for all modules"
  454. depends on MODULES
  455. help
  456. Modules which contain a MODULE_VERSION get an extra "srcversion"
  457. field inserted into their modinfo section, which contains a
  458. sum of the source files which made it. This helps maintainers
  459. see exactly which source was used to build a module (since
  460. others sometimes change the module source without updating
  461. the version). With this option, such a "srcversion" field
  462. will be created for all modules. If unsure, say N.
  463. config KMOD
  464. bool "Automatic kernel module loading"
  465. depends on MODULES
  466. help
  467. Normally when you have selected some parts of the kernel to
  468. be created as kernel modules, you must load them (using the
  469. "modprobe" command) before you can use them. If you say Y
  470. here, some parts of the kernel will be able to load modules
  471. automatically: when a part of the kernel needs a module, it
  472. runs modprobe with the appropriate arguments, thereby
  473. loading the module if it is available. If unsure, say Y.
  474. config STOP_MACHINE
  475. bool
  476. default y
  477. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  478. help
  479. Need stop_machine() primitive.
  480. endmenu
  481. menu "Block layer"
  482. source "block/Kconfig"
  483. endmenu