Kconfig 19 KB

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 drivers that have been replaced by something else, and/or are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