Kconfig 19 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 drivers that have been replaced by something else, and/or are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 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. Maximum of each of the number of arguments and environment
  55. variables 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 LOCALVERSION_AUTO
  68. bool "Automatically append version information to the version string"
  69. default y
  70. help
  71. This will try to automatically determine if the current tree is a
  72. release tree by looking for git tags that
  73. belong to the current top of tree revision.
  74. A string of the format -gxxxxxxxx will be added to the localversion
  75. if a git based tree is found. The string generated by this will be
  76. appended after any matching localversion* files, and after the value
  77. set in CONFIG_LOCALVERSION
  78. Note: This requires Perl, and a git repository, but not necessarily
  79. the git or cogito tools to be installed.
  80. config SWAP
  81. bool "Support for paging of anonymous memory (swap)"
  82. depends on MMU
  83. default y
  84. help
  85. This option allows you to choose whether you want to have support
  86. for socalled swap devices or swap files in your kernel that are
  87. used to provide more virtual memory than the actual RAM present
  88. in your computer. If unsure say Y.
  89. config SYSVIPC
  90. bool "System V IPC"
  91. ---help---
  92. Inter Process Communication is a suite of library functions and
  93. system calls which let processes (running programs) synchronize and
  94. exchange information. It is generally considered to be a good thing,
  95. and some programs won't run unless you say Y here. In particular, if
  96. you want to run the DOS emulator dosemu under Linux (read the
  97. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  98. you'll need to say Y here.
  99. You can find documentation about IPC with "info ipc" and also in
  100. section 6.4 of the Linux Programmer's Guide, available from
  101. <http://www.tldp.org/guides.html>.
  102. config POSIX_MQUEUE
  103. bool "POSIX Message Queues"
  104. depends on NET && EXPERIMENTAL
  105. ---help---
  106. POSIX variant of message queues is a part of IPC. In POSIX message
  107. queues every message has a priority which decides about succession
  108. of receiving it by a process. If you want to compile and run
  109. programs written e.g. for Solaris with use of its POSIX message
  110. queues (functions mq_*) say Y here. To use this feature you will
  111. also need mqueue library, available from
  112. <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
  113. POSIX message queues are visible as a filesystem called 'mqueue'
  114. and can be mounted somewhere if you want to do filesystem
  115. operations on message queues.
  116. If unsure, say Y.
  117. config BSD_PROCESS_ACCT
  118. bool "BSD Process Accounting"
  119. help
  120. If you say Y here, a user level program will be able to instruct the
  121. kernel (via a special system call) to write process accounting
  122. information to a file: whenever a process exits, information about
  123. that process will be appended to the file by the kernel. The
  124. information includes things such as creation time, owning user,
  125. command name, memory usage, controlling terminal etc. (the complete
  126. list is in the struct acct in <file:include/linux/acct.h>). It is
  127. up to the user level program to do useful things with this
  128. information. This is generally a good idea, so say Y.
  129. config BSD_PROCESS_ACCT_V3
  130. bool "BSD Process Accounting version 3 file format"
  131. depends on BSD_PROCESS_ACCT
  132. default n
  133. help
  134. If you say Y here, the process accounting information is written
  135. in a new file format that also logs the process IDs of each
  136. process and it's parent. Note that this file format is incompatible
  137. with previous v0/v1/v2 file formats, so you will need updated tools
  138. for processing it. A preliminary version of these tools is available
  139. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  140. config SYSCTL
  141. bool "Sysctl support"
  142. ---help---
  143. The sysctl interface provides a means of dynamically changing
  144. certain kernel parameters and variables on the fly without requiring
  145. a recompile of the kernel or reboot of the system. The primary
  146. interface consists of a system call, but if you say Y to "/proc
  147. file system support", a tree of modifiable sysctl entries will be
  148. generated beneath the /proc/sys directory. They are explained in the
  149. files in <file:Documentation/sysctl/>. Note that enabling this
  150. option will enlarge the kernel by at least 8 KB.
  151. As it is generally a good thing, you should say Y here unless
  152. building a kernel for install/rescue disks or your system is very
  153. limited in memory.
  154. config AUDIT
  155. bool "Auditing support"
  156. depends on NET
  157. default y if SECURITY_SELINUX
  158. help
  159. Enable auditing infrastructure that can be used with another
  160. kernel subsystem, such as SELinux (which requires this for
  161. logging of avc messages output). Does not do system-call
  162. auditing without CONFIG_AUDITSYSCALL.
  163. config AUDITSYSCALL
  164. bool "Enable system-call auditing support"
  165. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  166. default y if SECURITY_SELINUX
  167. help
  168. Enable low-overhead system-call auditing infrastructure that
  169. can be used independently or with another kernel subsystem,
  170. such as SELinux.
  171. config IKCONFIG
  172. bool "Kernel .config support"
  173. ---help---
  174. This option enables the complete Linux kernel ".config" file
  175. contents to be saved in the kernel. It provides documentation
  176. of which kernel options are used in a running kernel or in an
  177. on-disk kernel. This information can be extracted from the kernel
  178. image file with the script scripts/extract-ikconfig and used as
  179. input to rebuild the current kernel or to build another kernel.
  180. It can also be extracted from a running kernel by reading
  181. /proc/config.gz if enabled (below).
  182. config IKCONFIG_PROC
  183. bool "Enable access to .config through /proc/config.gz"
  184. depends on IKCONFIG && PROC_FS
  185. ---help---
  186. This option enables access to the kernel configuration file
  187. through /proc/config.gz.
  188. config CPUSETS
  189. bool "Cpuset support"
  190. depends on SMP
  191. help
  192. This option will let you create and manage CPUSETs which
  193. allow dynamically partitioning a system into sets of CPUs and
  194. Memory Nodes and assigning tasks to run only within those sets.
  195. This is primarily useful on large SMP or NUMA systems.
  196. Say N if unsure.
  197. source "usr/Kconfig"
  198. config UID16
  199. bool "Enable 16-bit UID system calls" if EMBEDDED
  200. depends !ALPHA && !PPC && !PPC64 && !PARISC && !V850 && !ARCH_S390X
  201. depends !X86_64 || IA32_EMULATION
  202. depends !SPARC64 || SPARC32_COMPAT
  203. default y
  204. help
  205. This enables the legacy 16-bit UID syscall wrappers.
  206. config VM86
  207. depends X86
  208. default y
  209. bool "Enable VM86 support" if EMBEDDED
  210. help
  211. This option is required by programs like DOSEMU to run 16-bit legacy
  212. code on X86 processors. It also may be needed by software like
  213. XFree86 to initialize some video cards via BIOS. Disabling this
  214. option saves about 6k.
  215. config CC_OPTIMIZE_FOR_SIZE
  216. bool "Optimize for size (Look out for broken compilers!)"
  217. default y
  218. depends on ARM || H8300 || EXPERIMENTAL
  219. help
  220. Enabling this option will pass "-Os" instead of "-O2" to gcc
  221. resulting in a smaller kernel.
  222. WARNING: some versions of gcc may generate incorrect code with this
  223. option. If problems are observed, a gcc upgrade may be needed.
  224. If unsure, say N.
  225. menuconfig EMBEDDED
  226. bool "Configure standard kernel features (for small systems)"
  227. help
  228. This option allows certain base kernel options and settings
  229. to be disabled or tweaked. This is for specialized
  230. environments which can tolerate a "non-standard" kernel.
  231. Only use this if you really know what you are doing.
  232. config KALLSYMS
  233. bool "Load all symbols for debugging/kksymoops" if EMBEDDED
  234. default y
  235. help
  236. Say Y here to let the kernel print out symbolic crash information and
  237. symbolic stack backtraces. This increases the size of the kernel
  238. somewhat, as all symbols have to be loaded into the kernel image.
  239. config KALLSYMS_ALL
  240. bool "Include all symbols in kallsyms"
  241. depends on DEBUG_KERNEL && KALLSYMS
  242. help
  243. Normally kallsyms only contains the symbols of functions, for nicer
  244. OOPS messages. Some debuggers can use kallsyms for other
  245. symbols too: say Y here to include all symbols, if you need them
  246. and you don't care about adding 300k to the size of your kernel.
  247. Say N.
  248. config KALLSYMS_EXTRA_PASS
  249. bool "Do an extra kallsyms pass"
  250. depends on KALLSYMS
  251. help
  252. If kallsyms is not working correctly, the build will fail with
  253. inconsistent kallsyms data. If that occurs, log a bug report and
  254. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  255. Always say N here unless you find a bug in kallsyms, which must be
  256. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  257. you wait for kallsyms to be fixed.
  258. config HOTPLUG
  259. bool "Support for hot-pluggable devices" if EMBEDDED
  260. default y
  261. help
  262. This option is provided for the case where no hotplug or uevent
  263. capabilities is wanted by the kernel. You should only consider
  264. disabling this option for embedded systems that do not use modules, a
  265. dynamic /dev tree, or dynamic device discovery. Just say Y.
  266. config PRINTK
  267. default y
  268. bool "Enable support for printk" if EMBEDDED
  269. help
  270. This option enables normal printk support. Removing it
  271. eliminates most of the message strings from the kernel image
  272. and makes the kernel more or less silent. As this makes it
  273. very difficult to diagnose system problems, saying N here is
  274. strongly discouraged.
  275. config BUG
  276. bool "BUG() support" if EMBEDDED
  277. default y
  278. help
  279. Disabling this option eliminates support for BUG and WARN, reducing
  280. the size of your kernel image and potentially quietly ignoring
  281. numerous fatal conditions. You should only consider disabling this
  282. option for embedded systems with no facilities for reporting errors.
  283. Just say Y.
  284. config DOUBLEFAULT
  285. depends X86
  286. default y if X86
  287. bool "Enable doublefault exception handler" if EMBEDDED
  288. help
  289. This option allows trapping of rare doublefault exceptions that
  290. would otherwise cause a system to silently reboot. Disabling this
  291. option saves about 4k.
  292. config ELF_CORE
  293. default y
  294. bool "Enable ELF core dumps" if EMBEDDED
  295. help
  296. Enable support for generating core dumps. Disabling saves about 4k.
  297. config BASE_FULL
  298. default y
  299. bool "Enable full-sized data structures for core" if EMBEDDED
  300. help
  301. Disabling this option reduces the size of miscellaneous core
  302. kernel data structures. This saves memory on small machines,
  303. but may reduce performance.
  304. config FUTEX
  305. bool "Enable futex support" if EMBEDDED
  306. default y
  307. help
  308. Disabling this option will cause the kernel to be built without
  309. support for "fast userspace mutexes". The resulting kernel may not
  310. run glibc-based applications correctly.
  311. config EPOLL
  312. bool "Enable eventpoll support" if EMBEDDED
  313. default y
  314. help
  315. Disabling this option will cause the kernel to be built without
  316. support for epoll family of system calls.
  317. config SHMEM
  318. bool "Use full shmem filesystem" if EMBEDDED
  319. default y
  320. depends on MMU
  321. help
  322. The shmem is an internal filesystem used to manage shared memory.
  323. It is backed by swap and manages resource limits. It is also exported
  324. to userspace as tmpfs if TMPFS is enabled. Disabling this
  325. option replaces shmem and tmpfs with the much simpler ramfs code,
  326. which may be appropriate on small systems without swap.
  327. config CC_ALIGN_FUNCTIONS
  328. int "Function alignment" if EMBEDDED
  329. default 0
  330. help
  331. Align the start of functions to the next power-of-two greater than n,
  332. skipping up to n bytes. For instance, 32 aligns functions
  333. to the next 32-byte boundary, but 24 would align to the next
  334. 32-byte boundary only if this can be done by skipping 23 bytes or less.
  335. Zero means use compiler's default.
  336. config CC_ALIGN_LABELS
  337. int "Label alignment" if EMBEDDED
  338. default 0
  339. help
  340. Align all branch targets to a power-of-two boundary, skipping
  341. up to n bytes like ALIGN_FUNCTIONS. This option can easily
  342. make code slower, because it must insert dummy operations for
  343. when the branch target is reached in the usual flow of the code.
  344. Zero means use compiler's default.
  345. config CC_ALIGN_LOOPS
  346. int "Loop alignment" if EMBEDDED
  347. default 0
  348. help
  349. Align loops to a power-of-two boundary, skipping up to n bytes.
  350. Zero means use compiler's default.
  351. config CC_ALIGN_JUMPS
  352. int "Jump alignment" if EMBEDDED
  353. default 0
  354. help
  355. Align branch targets to a power-of-two boundary, for branch
  356. targets where the targets can only be reached by jumping,
  357. skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
  358. no dummy operations need be executed.
  359. Zero means use compiler's default.
  360. config SLAB
  361. default y
  362. bool "Use full SLAB allocator" if EMBEDDED
  363. help
  364. Disabling this replaces the advanced SLAB allocator and
  365. kmalloc support with the drastically simpler SLOB allocator.
  366. SLOB is more space efficient but does not scale well and is
  367. more susceptible to fragmentation.
  368. endmenu # General setup
  369. config TINY_SHMEM
  370. default !SHMEM
  371. bool
  372. config BASE_SMALL
  373. int
  374. default 0 if BASE_FULL
  375. default 1 if !BASE_FULL
  376. config SLOB
  377. default !SLAB
  378. bool
  379. menu "Loadable module support"
  380. config MODULES
  381. bool "Enable loadable module support"
  382. help
  383. Kernel modules are small pieces of compiled code which can
  384. be inserted in the running kernel, rather than being
  385. permanently built into the kernel. You use the "modprobe"
  386. tool to add (and sometimes remove) them. If you say Y here,
  387. many parts of the kernel can be built as modules (by
  388. answering M instead of Y where indicated): this is most
  389. useful for infrequently used options which are not required
  390. for booting. For more information, see the man pages for
  391. modprobe, lsmod, modinfo, insmod and rmmod.
  392. If you say Y here, you will need to run "make
  393. modules_install" to put the modules under /lib/modules/
  394. where modprobe can find them (you may need to be root to do
  395. this).
  396. If unsure, say Y.
  397. config MODULE_UNLOAD
  398. bool "Module unloading"
  399. depends on MODULES
  400. help
  401. Without this option you will not be able to unload any
  402. modules (note that some modules may not be unloadable
  403. anyway), which makes your kernel slightly smaller and
  404. simpler. If unsure, say Y.
  405. config MODULE_FORCE_UNLOAD
  406. bool "Forced module unloading"
  407. depends on MODULE_UNLOAD && EXPERIMENTAL
  408. help
  409. This option allows you to force a module to unload, even if the
  410. kernel believes it is unsafe: the kernel will remove the module
  411. without waiting for anyone to stop using it (using the -f option to
  412. rmmod). This is mainly for kernel developers and desperate users.
  413. If unsure, say N.
  414. config OBSOLETE_MODPARM
  415. bool
  416. default y
  417. depends on MODULES
  418. help
  419. You need this option to use module parameters on modules which
  420. have not been converted to the new module parameter system yet.
  421. If unsure, say Y.
  422. config MODVERSIONS
  423. bool "Module versioning support"
  424. depends on MODULES
  425. help
  426. Usually, you have to use modules compiled with your kernel.
  427. Saying Y here makes it sometimes possible to use modules
  428. compiled for different kernels, by adding enough information
  429. to the modules to (hopefully) spot any changes which would
  430. make them incompatible with the kernel you are running. If
  431. unsure, say N.
  432. config MODULE_SRCVERSION_ALL
  433. bool "Source checksum for all modules"
  434. depends on MODULES
  435. help
  436. Modules which contain a MODULE_VERSION get an extra "srcversion"
  437. field inserted into their modinfo section, which contains a
  438. sum of the source files which made it. This helps maintainers
  439. see exactly which source was used to build a module (since
  440. others sometimes change the module source without updating
  441. the version). With this option, such a "srcversion" field
  442. will be created for all modules. If unsure, say N.
  443. config KMOD
  444. bool "Automatic kernel module loading"
  445. depends on MODULES
  446. help
  447. Normally when you have selected some parts of the kernel to
  448. be created as kernel modules, you must load them (using the
  449. "modprobe" command) before you can use them. If you say Y
  450. here, some parts of the kernel will be able to load modules
  451. automatically: when a part of the kernel needs a module, it
  452. runs modprobe with the appropriate arguments, thereby
  453. loading the module if it is available. If unsure, say Y.
  454. config STOP_MACHINE
  455. bool
  456. default y
  457. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  458. help
  459. Need stop_machine() primitive.
  460. endmenu
  461. menu "Block layer"
  462. source "block/Kconfig"
  463. endmenu