Kconfig 17 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484
  1. menu "Code maturity level options"
  2. config EXPERIMENTAL
  3. bool "Prompt for development and/or incomplete code/drivers"
  4. ---help---
  5. Some of the various things that Linux supports (such as network
  6. drivers, file systems, network protocols, etc.) can be in a state
  7. of development where the functionality, stability, or the level of
  8. testing is not yet high enough for general use. This is usually
  9. known as the "alpha-test" phase among developers. If a feature is
  10. currently in alpha-test, then the developers usually discourage
  11. uninformed widespread use of this feature by the general public to
  12. avoid "Why doesn't this work?" type mail messages. However, active
  13. testing and use of these systems is welcomed. Just be aware that it
  14. may not meet the normal level of reliability or it may fail to work
  15. in some special cases. Detailed bug reports from people familiar
  16. with the kernel internals are usually welcomed by the developers
  17. (before submitting bug reports, please read the documents
  18. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  19. <file:Documentation/BUG-HUNTING>, and
  20. <file:Documentation/oops-tracing.txt> in the kernel source).
  21. This option will also make obsoleted drivers available. These are
  22. drivers that have been replaced by something else, and/or are
  23. scheduled to be removed in a future kernel release.
  24. Unless you intend to help test and develop a feature or driver that
  25. falls into this category, or you have a situation that requires
  26. using these features, you should probably say N here, which will
  27. cause the configurator to present you with fewer choices. If
  28. you say Y here, you will be offered the choice of using features or
  29. drivers that are currently considered to be in the alpha-test phase.
  30. config CLEAN_COMPILE
  31. bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
  32. default y
  33. help
  34. Select this option if you don't even want to see the option
  35. to configure known-broken drivers.
  36. If unsure, say Y
  37. config BROKEN
  38. bool
  39. depends on !CLEAN_COMPILE
  40. default y
  41. config BROKEN_ON_SMP
  42. bool
  43. depends on BROKEN || !SMP
  44. default y
  45. config LOCK_KERNEL
  46. bool
  47. depends on SMP || PREEMPT
  48. default y
  49. config INIT_ENV_ARG_LIMIT
  50. int
  51. default 32 if !USERMODE
  52. default 128 if USERMODE
  53. help
  54. This is the value of the two limits on the number of argument and of
  55. env.var passed to init from the kernel command line.
  56. endmenu
  57. menu "General setup"
  58. config LOCALVERSION
  59. string "Local version - append to kernel release"
  60. help
  61. Append an extra string to the end of your kernel version.
  62. This will show up when you type uname, for example.
  63. The string you set here will be appended after the contents of
  64. any files with a filename matching localversion* in your
  65. object and source tree, in that order. Your total string can
  66. be a maximum of 64 characters.
  67. config SWAP
  68. bool "Support for paging of anonymous memory (swap)"
  69. depends on MMU
  70. default y
  71. help
  72. This option allows you to choose whether you want to have support
  73. for socalled swap devices or swap files in your kernel that are
  74. used to provide more virtual memory than the actual RAM present
  75. in your computer. If unsure say Y.
  76. config SYSVIPC
  77. bool "System V IPC"
  78. depends on MMU
  79. ---help---
  80. Inter Process Communication is a suite of library functions and
  81. system calls which let processes (running programs) synchronize and
  82. exchange information. It is generally considered to be a good thing,
  83. and some programs won't run unless you say Y here. In particular, if
  84. you want to run the DOS emulator dosemu under Linux (read the
  85. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  86. you'll need to say Y here.
  87. You can find documentation about IPC with "info ipc" and also in
  88. section 6.4 of the Linux Programmer's Guide, available from
  89. <http://www.tldp.org/guides.html>.
  90. config POSIX_MQUEUE
  91. bool "POSIX Message Queues"
  92. depends on NET && EXPERIMENTAL
  93. ---help---
  94. POSIX variant of message queues is a part of IPC. In POSIX message
  95. queues every message has a priority which decides about succession
  96. of receiving it by a process. If you want to compile and run
  97. programs written e.g. for Solaris with use of its POSIX message
  98. queues (functions mq_*) say Y here. To use this feature you will
  99. also need mqueue library, available from
  100. <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
  101. POSIX message queues are visible as a filesystem called 'mqueue'
  102. and can be mounted somewhere if you want to do filesystem
  103. operations on message queues.
  104. If unsure, say Y.
  105. config BSD_PROCESS_ACCT
  106. bool "BSD Process Accounting"
  107. help
  108. If you say Y here, a user level program will be able to instruct the
  109. kernel (via a special system call) to write process accounting
  110. information to a file: whenever a process exits, information about
  111. that process will be appended to the file by the kernel. The
  112. information includes things such as creation time, owning user,
  113. command name, memory usage, controlling terminal etc. (the complete
  114. list is in the struct acct in <file:include/linux/acct.h>). It is
  115. up to the user level program to do useful things with this
  116. information. This is generally a good idea, so say Y.
  117. config BSD_PROCESS_ACCT_V3
  118. bool "BSD Process Accounting version 3 file format"
  119. depends on BSD_PROCESS_ACCT
  120. default n
  121. help
  122. If you say Y here, the process accounting information is written
  123. in a new file format that also logs the process IDs of each
  124. process and it's parent. Note that this file format is incompatible
  125. with previous v0/v1/v2 file formats, so you will need updated tools
  126. for processing it. A preliminary version of these tools is available
  127. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  128. config SYSCTL
  129. bool "Sysctl support"
  130. ---help---
  131. The sysctl interface provides a means of dynamically changing
  132. certain kernel parameters and variables on the fly without requiring
  133. a recompile of the kernel or reboot of the system. The primary
  134. interface consists of a system call, but if you say Y to "/proc
  135. file system support", a tree of modifiable sysctl entries will be
  136. generated beneath the /proc/sys directory. They are explained in the
  137. files in <file:Documentation/sysctl/>. Note that enabling this
  138. option will enlarge the kernel by at least 8 KB.
  139. As it is generally a good thing, you should say Y here unless
  140. building a kernel for install/rescue disks or your system is very
  141. limited in memory.
  142. config AUDIT
  143. bool "Auditing support"
  144. default y if SECURITY_SELINUX
  145. help
  146. Enable auditing infrastructure that can be used with another
  147. kernel subsystem, such as SELinux (which requires this for
  148. logging of avc messages output). Does not do system-call
  149. auditing without CONFIG_AUDITSYSCALL.
  150. config AUDITSYSCALL
  151. bool "Enable system-call auditing support"
  152. depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
  153. default y if SECURITY_SELINUX
  154. help
  155. Enable low-overhead system-call auditing infrastructure that
  156. can be used independently or with another kernel subsystem,
  157. such as SELinux.
  158. config HOTPLUG
  159. bool "Support for hot-pluggable devices" if !ARCH_S390
  160. default ARCH_S390
  161. help
  162. This option is provided for the case where no in-kernel-tree
  163. modules require HOTPLUG functionality, but a module built
  164. outside the kernel tree does. Such modules require Y here.
  165. config KOBJECT_UEVENT
  166. bool "Kernel Userspace Events"
  167. depends on NET
  168. default y
  169. help
  170. This option enables the kernel userspace event layer, which is a
  171. simple mechanism for kernel-to-user communication over a netlink
  172. socket.
  173. The goal of the kernel userspace events layer is to provide a simple
  174. and efficient events system, that notifies userspace about kobject
  175. state changes. This will enable applications to just listen for
  176. events instead of polling system devices and files.
  177. Hotplug events (kobject addition and removal) are also available on
  178. the netlink socket in addition to the execution of /sbin/hotplug if
  179. CONFIG_HOTPLUG is enabled.
  180. Say Y, unless you are building a system requiring minimal memory
  181. consumption.
  182. config IKCONFIG
  183. bool "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 options will let you create and manage CPUSET's 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. menuconfig EMBEDDED
  209. bool "Configure standard kernel features (for small systems)"
  210. help
  211. This option allows certain base kernel options and settings
  212. to be disabled or tweaked. This is for specialized
  213. environments which can tolerate a "non-standard" kernel.
  214. Only use this if you really know what you are doing.
  215. config KALLSYMS
  216. bool "Load all symbols for debugging/kksymoops" if EMBEDDED
  217. default y
  218. help
  219. Say Y here to let the kernel print out symbolic crash information and
  220. symbolic stack backtraces. This increases the size of the kernel
  221. somewhat, as all symbols have to be loaded into the kernel image.
  222. config KALLSYMS_ALL
  223. bool "Include all symbols in kallsyms"
  224. depends on DEBUG_KERNEL && KALLSYMS
  225. help
  226. Normally kallsyms only contains the symbols of functions, for nicer
  227. OOPS messages. Some debuggers can use kallsyms for other
  228. symbols too: say Y here to include all symbols, and you
  229. don't care about adding 300k to the size of your kernel.
  230. Say N.
  231. config KALLSYMS_EXTRA_PASS
  232. bool "Do an extra kallsyms pass"
  233. depends on KALLSYMS
  234. help
  235. If kallsyms is not working correctly, the build will fail with
  236. inconsistent kallsyms data. If that occurs, log a bug report and
  237. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  238. Always say N here unless you find a bug in kallsyms, which must be
  239. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  240. you wait for kallsyms to be fixed.
  241. config PRINTK
  242. default y
  243. bool "Enable support for printk" if EMBEDDED
  244. help
  245. This option enables normal printk support. Removing it
  246. eliminates most of the message strings from the kernel image
  247. and makes the kernel more or less silent. As this makes it
  248. very difficult to diagnose system problems, saying N here is
  249. strongly discouraged.
  250. config BUG
  251. bool "BUG() support" if EMBEDDED
  252. default y
  253. help
  254. Disabling this option eliminates support for BUG and WARN, reducing
  255. the size of your kernel image and potentially quietly ignoring
  256. numerous fatal conditions. You should only consider disabling this
  257. option for embedded systems with no facilities for reporting errors.
  258. Just say Y.
  259. config BASE_FULL
  260. default y
  261. bool "Enable full-sized data structures for core" if EMBEDDED
  262. help
  263. Disabling this option reduces the size of miscellaneous core
  264. kernel data structures. This saves memory on small machines,
  265. but may reduce performance.
  266. config FUTEX
  267. bool "Enable futex support" if EMBEDDED
  268. default y
  269. help
  270. Disabling this option will cause the kernel to be built without
  271. support for "fast userspace mutexes". The resulting kernel may not
  272. run glibc-based applications correctly.
  273. config EPOLL
  274. bool "Enable eventpoll support" if EMBEDDED
  275. default y
  276. help
  277. Disabling this option will cause the kernel to be built without
  278. support for epoll family of system calls.
  279. config CC_OPTIMIZE_FOR_SIZE
  280. bool "Optimize for size" if EMBEDDED
  281. default y if ARM || H8300
  282. help
  283. Enabling this option will pass "-Os" instead of "-O2" to gcc
  284. resulting in a smaller kernel.
  285. WARNING: some versions of gcc may generate incorrect code with this
  286. option. If problems are observed, a gcc upgrade may be needed.
  287. If unsure, say N.
  288. config SHMEM
  289. bool "Use full shmem filesystem" if EMBEDDED
  290. default y
  291. depends on MMU
  292. help
  293. The shmem is an internal filesystem used to manage shared memory.
  294. It is backed by swap and manages resource limits. It is also exported
  295. to userspace as tmpfs if TMPFS is enabled. Disabling this
  296. option replaces shmem and tmpfs with the much simpler ramfs code,
  297. which may be appropriate on small systems without swap.
  298. config CC_ALIGN_FUNCTIONS
  299. int "Function alignment" if EMBEDDED
  300. default 0
  301. help
  302. Align the start of functions to the next power-of-two greater than n,
  303. skipping up to n bytes. For instance, 32 aligns functions
  304. to the next 32-byte boundary, but 24 would align to the next
  305. 32-byte boundary only if this can be done by skipping 23 bytes or less.
  306. Zero means use compiler's default.
  307. config CC_ALIGN_LABELS
  308. int "Label alignment" if EMBEDDED
  309. default 0
  310. help
  311. Align all branch targets to a power-of-two boundary, skipping
  312. up to n bytes like ALIGN_FUNCTIONS. This option can easily
  313. make code slower, because it must insert dummy operations for
  314. when the branch target is reached in the usual flow of the code.
  315. Zero means use compiler's default.
  316. config CC_ALIGN_LOOPS
  317. int "Loop alignment" if EMBEDDED
  318. default 0
  319. help
  320. Align loops to a power-of-two boundary, skipping up to n bytes.
  321. Zero means use compiler's default.
  322. config CC_ALIGN_JUMPS
  323. int "Jump alignment" if EMBEDDED
  324. default 0
  325. help
  326. Align branch targets to a power-of-two boundary, for branch
  327. targets where the targets can only be reached by jumping,
  328. skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
  329. no dummy operations need be executed.
  330. Zero means use compiler's default.
  331. endmenu # General setup
  332. config TINY_SHMEM
  333. default !SHMEM
  334. bool
  335. config BASE_SMALL
  336. int
  337. default 0 if BASE_FULL
  338. default 1 if !BASE_FULL
  339. menu "Loadable module support"
  340. config MODULES
  341. bool "Enable loadable module support"
  342. help
  343. Kernel modules are small pieces of compiled code which can
  344. be inserted in the running kernel, rather than being
  345. permanently built into the kernel. You use the "modprobe"
  346. tool to add (and sometimes remove) them. If you say Y here,
  347. many parts of the kernel can be built as modules (by
  348. answering M instead of Y where indicated): this is most
  349. useful for infrequently used options which are not required
  350. for booting. For more information, see the man pages for
  351. modprobe, lsmod, modinfo, insmod and rmmod.
  352. If you say Y here, you will need to run "make
  353. modules_install" to put the modules under /lib/modules/
  354. where modprobe can find them (you may need to be root to do
  355. this).
  356. If unsure, say Y.
  357. config MODULE_UNLOAD
  358. bool "Module unloading"
  359. depends on MODULES
  360. help
  361. Without this option you will not be able to unload any
  362. modules (note that some modules may not be unloadable
  363. anyway), which makes your kernel slightly smaller and
  364. simpler. If unsure, say Y.
  365. config MODULE_FORCE_UNLOAD
  366. bool "Forced module unloading"
  367. depends on MODULE_UNLOAD && EXPERIMENTAL
  368. help
  369. This option allows you to force a module to unload, even if the
  370. kernel believes it is unsafe: the kernel will remove the module
  371. without waiting for anyone to stop using it (using the -f option to
  372. rmmod). This is mainly for kernel developers and desperate users.
  373. If unsure, say N.
  374. config OBSOLETE_MODPARM
  375. bool
  376. default y
  377. depends on MODULES
  378. help
  379. You need this option to use module parameters on modules which
  380. have not been converted to the new module parameter system yet.
  381. If unsure, say Y.
  382. config MODVERSIONS
  383. bool "Module versioning support (EXPERIMENTAL)"
  384. depends on MODULES && EXPERIMENTAL && !UML
  385. help
  386. Usually, you have to use modules compiled with your kernel.
  387. Saying Y here makes it sometimes possible to use modules
  388. compiled for different kernels, by adding enough information
  389. to the modules to (hopefully) spot any changes which would
  390. make them incompatible with the kernel you are running. If
  391. unsure, say N.
  392. config MODULE_SRCVERSION_ALL
  393. bool "Source checksum for all modules"
  394. depends on MODULES
  395. help
  396. Modules which contain a MODULE_VERSION get an extra "srcversion"
  397. field inserted into their modinfo section, which contains a
  398. sum of the source files which made it. This helps maintainers
  399. see exactly which source was used to build a module (since
  400. others sometimes change the module source without updating
  401. the version). With this option, such a "srcversion" field
  402. will be created for all modules. If unsure, say N.
  403. config KMOD
  404. bool "Automatic kernel module loading"
  405. depends on MODULES
  406. help
  407. Normally when you have selected some parts of the kernel to
  408. be created as kernel modules, you must load them (using the
  409. "modprobe" command) before you can use them. If you say Y
  410. here, some parts of the kernel will be able to load modules
  411. automatically: when a part of the kernel needs a module, it
  412. runs modprobe with the appropriate arguments, thereby
  413. loading the module if it is available. If unsure, say Y.
  414. config STOP_MACHINE
  415. bool
  416. default y
  417. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  418. help
  419. Need stop_machine() primitive.
  420. endmenu