Kconfig 18 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 drivers that have been replaced by something else, and/or are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"
  133. ---help---
  134. The sysctl interface provides a means of dynamically changing
  135. certain kernel parameters and variables on the fly without requiring
  136. a recompile of the kernel or reboot of the system. The primary
  137. interface consists of a system call, but if you say Y to "/proc
  138. file system support", a tree of modifiable sysctl entries will be
  139. generated beneath the /proc/sys directory. They are explained in the
  140. files in <file:Documentation/sysctl/>. Note that enabling this
  141. option will enlarge the kernel by at least 8 KB.
  142. As it is generally a good thing, you should say Y here unless
  143. building a kernel for install/rescue disks or your system is very
  144. limited in memory.
  145. config AUDIT
  146. bool "Auditing support"
  147. depends on NET
  148. default y if SECURITY_SELINUX
  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.
  162. config IKCONFIG
  163. bool "Kernel .config support"
  164. ---help---
  165. This option enables the complete Linux kernel ".config" file
  166. contents to be saved in the kernel. It provides documentation
  167. of which kernel options are used in a running kernel or in an
  168. on-disk kernel. This information can be extracted from the kernel
  169. image file with the script scripts/extract-ikconfig and used as
  170. input to rebuild the current kernel or to build another kernel.
  171. It can also be extracted from a running kernel by reading
  172. /proc/config.gz if enabled (below).
  173. config IKCONFIG_PROC
  174. bool "Enable access to .config through /proc/config.gz"
  175. depends on IKCONFIG && PROC_FS
  176. ---help---
  177. This option enables access to the kernel configuration file
  178. through /proc/config.gz.
  179. config CPUSETS
  180. bool "Cpuset support"
  181. depends on SMP
  182. help
  183. This option will let you create and manage CPUSETs which
  184. allow dynamically partitioning a system into sets of CPUs and
  185. Memory Nodes and assigning tasks to run only within those sets.
  186. This is primarily useful on large SMP or NUMA systems.
  187. Say N if unsure.
  188. source "usr/Kconfig"
  189. config UID16
  190. bool "Enable 16-bit UID system calls" if EMBEDDED
  191. depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  192. default y
  193. help
  194. This enables the legacy 16-bit UID syscall wrappers.
  195. config VM86
  196. depends X86
  197. default y
  198. bool "Enable VM86 support" if EMBEDDED
  199. help
  200. This option is required by programs like DOSEMU to run 16-bit legacy
  201. code on X86 processors. It also may be needed by software like
  202. XFree86 to initialize some video cards via BIOS. Disabling this
  203. option saves about 6k.
  204. config CC_OPTIMIZE_FOR_SIZE
  205. bool "Optimize for size (Look out for broken compilers!)"
  206. default y
  207. depends on ARM || H8300 || EXPERIMENTAL
  208. help
  209. Enabling this option will pass "-Os" instead of "-O2" to gcc
  210. resulting in a smaller kernel.
  211. WARNING: some versions of gcc may generate incorrect code with this
  212. option. If problems are observed, a gcc upgrade may be needed.
  213. If unsure, say N.
  214. menuconfig EMBEDDED
  215. bool "Configure standard kernel features (for small systems)"
  216. help
  217. This option allows certain base kernel options and settings
  218. to be disabled or tweaked. This is for specialized
  219. environments which can tolerate a "non-standard" kernel.
  220. Only use this if you really know what you are doing.
  221. config KALLSYMS
  222. bool "Load all symbols for debugging/kksymoops" if EMBEDDED
  223. default y
  224. help
  225. Say Y here to let the kernel print out symbolic crash information and
  226. symbolic stack backtraces. This increases the size of the kernel
  227. somewhat, as all symbols have to be loaded into the kernel image.
  228. config KALLSYMS_ALL
  229. bool "Include all symbols in kallsyms"
  230. depends on DEBUG_KERNEL && KALLSYMS
  231. help
  232. Normally kallsyms only contains the symbols of functions, for nicer
  233. OOPS messages. Some debuggers can use kallsyms for other
  234. symbols too: say Y here to include all symbols, if you need them
  235. and you don't care about adding 300k to the size of your kernel.
  236. Say N.
  237. config KALLSYMS_EXTRA_PASS
  238. bool "Do an extra kallsyms pass"
  239. depends on KALLSYMS
  240. help
  241. If kallsyms is not working correctly, the build will fail with
  242. inconsistent kallsyms data. If that occurs, log a bug report and
  243. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  244. Always say N here unless you find a bug in kallsyms, which must be
  245. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  246. you wait for kallsyms to be fixed.
  247. config HOTPLUG
  248. bool "Support for hot-pluggable devices" if EMBEDDED
  249. default y
  250. help
  251. This option is provided for the case where no hotplug or uevent
  252. capabilities is wanted by the kernel. You should only consider
  253. disabling this option for embedded systems that do not use modules, a
  254. dynamic /dev tree, or dynamic device discovery. Just say Y.
  255. config PRINTK
  256. default y
  257. bool "Enable support for printk" if EMBEDDED
  258. help
  259. This option enables normal printk support. Removing it
  260. eliminates most of the message strings from the kernel image
  261. and makes the kernel more or less silent. As this makes it
  262. very difficult to diagnose system problems, saying N here is
  263. strongly discouraged.
  264. config BUG
  265. bool "BUG() support" if EMBEDDED
  266. default y
  267. help
  268. Disabling this option eliminates support for BUG and WARN, reducing
  269. the size of your kernel image and potentially quietly ignoring
  270. numerous fatal conditions. You should only consider disabling this
  271. option for embedded systems with no facilities for reporting errors.
  272. Just say Y.
  273. config ELF_CORE
  274. default y
  275. bool "Enable ELF core dumps" if EMBEDDED
  276. help
  277. Enable support for generating core dumps. Disabling saves about 4k.
  278. config BASE_FULL
  279. default y
  280. bool "Enable full-sized data structures for core" if EMBEDDED
  281. help
  282. Disabling this option reduces the size of miscellaneous core
  283. kernel data structures. This saves memory on small machines,
  284. but may reduce performance.
  285. config FUTEX
  286. bool "Enable futex support" if EMBEDDED
  287. default y
  288. help
  289. Disabling this option will cause the kernel to be built without
  290. support for "fast userspace mutexes". The resulting kernel may not
  291. run glibc-based applications correctly.
  292. config EPOLL
  293. bool "Enable eventpoll support" if EMBEDDED
  294. default y
  295. help
  296. Disabling this option will cause the kernel to be built without
  297. support for epoll family of system calls.
  298. config SHMEM
  299. bool "Use full shmem filesystem" if EMBEDDED
  300. default y
  301. depends on MMU
  302. help
  303. The shmem is an internal filesystem used to manage shared memory.
  304. It is backed by swap and manages resource limits. It is also exported
  305. to userspace as tmpfs if TMPFS is enabled. Disabling this
  306. option replaces shmem and tmpfs with the much simpler ramfs code,
  307. which may be appropriate on small systems without swap.
  308. config CC_ALIGN_FUNCTIONS
  309. int "Function alignment" if EMBEDDED
  310. default 0
  311. help
  312. Align the start of functions to the next power-of-two greater than n,
  313. skipping up to n bytes. For instance, 32 aligns functions
  314. to the next 32-byte boundary, but 24 would align to the next
  315. 32-byte boundary only if this can be done by skipping 23 bytes or less.
  316. Zero means use compiler's default.
  317. config CC_ALIGN_LABELS
  318. int "Label alignment" if EMBEDDED
  319. default 0
  320. help
  321. Align all branch targets to a power-of-two boundary, skipping
  322. up to n bytes like ALIGN_FUNCTIONS. This option can easily
  323. make code slower, because it must insert dummy operations for
  324. when the branch target is reached in the usual flow of the code.
  325. Zero means use compiler's default.
  326. config CC_ALIGN_LOOPS
  327. int "Loop alignment" if EMBEDDED
  328. default 0
  329. help
  330. Align loops to a power-of-two boundary, skipping up to n bytes.
  331. Zero means use compiler's default.
  332. config CC_ALIGN_JUMPS
  333. int "Jump alignment" if EMBEDDED
  334. default 0
  335. help
  336. Align branch targets to a power-of-two boundary, for branch
  337. targets where the targets can only be reached by jumping,
  338. skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
  339. no dummy operations need be executed.
  340. Zero means use compiler's default.
  341. config SLAB
  342. default y
  343. bool "Use full SLAB allocator" if EMBEDDED
  344. help
  345. Disabling this replaces the advanced SLAB allocator and
  346. kmalloc support with the drastically simpler SLOB allocator.
  347. SLOB is more space efficient but does not scale well and is
  348. more susceptible to fragmentation.
  349. endmenu # General setup
  350. config TINY_SHMEM
  351. default !SHMEM
  352. bool
  353. config BASE_SMALL
  354. int
  355. default 0 if BASE_FULL
  356. default 1 if !BASE_FULL
  357. config SLOB
  358. default !SLAB
  359. bool
  360. config OBSOLETE_INTERMODULE
  361. tristate
  362. menu "Loadable module support"
  363. config MODULES
  364. bool "Enable loadable module support"
  365. help
  366. Kernel modules are small pieces of compiled code which can
  367. be inserted in the running kernel, rather than being
  368. permanently built into the kernel. You use the "modprobe"
  369. tool to add (and sometimes remove) them. If you say Y here,
  370. many parts of the kernel can be built as modules (by
  371. answering M instead of Y where indicated): this is most
  372. useful for infrequently used options which are not required
  373. for booting. For more information, see the man pages for
  374. modprobe, lsmod, modinfo, insmod and rmmod.
  375. If you say Y here, you will need to run "make
  376. modules_install" to put the modules under /lib/modules/
  377. where modprobe can find them (you may need to be root to do
  378. this).
  379. If unsure, say Y.
  380. config MODULE_UNLOAD
  381. bool "Module unloading"
  382. depends on MODULES
  383. help
  384. Without this option you will not be able to unload any
  385. modules (note that some modules may not be unloadable
  386. anyway), which makes your kernel slightly smaller and
  387. simpler. If unsure, say Y.
  388. config MODULE_FORCE_UNLOAD
  389. bool "Forced module unloading"
  390. depends on MODULE_UNLOAD && EXPERIMENTAL
  391. help
  392. This option allows you to force a module to unload, even if the
  393. kernel believes it is unsafe: the kernel will remove the module
  394. without waiting for anyone to stop using it (using the -f option to
  395. rmmod). This is mainly for kernel developers and desperate users.
  396. If unsure, say N.
  397. config OBSOLETE_MODPARM
  398. bool
  399. default y
  400. depends on MODULES
  401. help
  402. You need this option to use module parameters on modules which
  403. have not been converted to the new module parameter system yet.
  404. If unsure, say Y.
  405. config MODVERSIONS
  406. bool "Module versioning support"
  407. depends on MODULES
  408. help
  409. Usually, you have to use modules compiled with your kernel.
  410. Saying Y here makes it sometimes possible to use modules
  411. compiled for different kernels, by adding enough information
  412. to the modules to (hopefully) spot any changes which would
  413. make them incompatible with the kernel you are running. If
  414. unsure, say N.
  415. config MODULE_SRCVERSION_ALL
  416. bool "Source checksum for all modules"
  417. depends on MODULES
  418. help
  419. Modules which contain a MODULE_VERSION get an extra "srcversion"
  420. field inserted into their modinfo section, which contains a
  421. sum of the source files which made it. This helps maintainers
  422. see exactly which source was used to build a module (since
  423. others sometimes change the module source without updating
  424. the version). With this option, such a "srcversion" field
  425. will be created for all modules. If unsure, say N.
  426. config KMOD
  427. bool "Automatic kernel module loading"
  428. depends on MODULES
  429. help
  430. Normally when you have selected some parts of the kernel to
  431. be created as kernel modules, you must load them (using the
  432. "modprobe" command) before you can use them. If you say Y
  433. here, some parts of the kernel will be able to load modules
  434. automatically: when a part of the kernel needs a module, it
  435. runs modprobe with the appropriate arguments, thereby
  436. loading the module if it is available. If unsure, say Y.
  437. config STOP_MACHINE
  438. bool
  439. default y
  440. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  441. help
  442. Need stop_machine() primitive.
  443. endmenu
  444. menu "Block layer"
  445. source "block/Kconfig"
  446. endmenu