Kconfig 17 KB

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 drivers that have been replaced by something else, and/or are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