Kconfig 20 KB

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  1. config DEFCONFIG_LIST
  2. string
  3. depends on !UML
  4. option defconfig_list
  5. default "/lib/modules/$UNAME_RELEASE/.config"
  6. default "/etc/kernel-config"
  7. default "/boot/config-$UNAME_RELEASE"
  8. default "arch/$ARCH/defconfig"
  9. menu "Code maturity level options"
  10. config EXPERIMENTAL
  11. bool "Prompt for development and/or incomplete code/drivers"
  12. ---help---
  13. Some of the various things that Linux supports (such as network
  14. drivers, file systems, network protocols, etc.) can be in a state
  15. of development where the functionality, stability, or the level of
  16. testing is not yet high enough for general use. This is usually
  17. known as the "alpha-test" phase among developers. If a feature is
  18. currently in alpha-test, then the developers usually discourage
  19. uninformed widespread use of this feature by the general public to
  20. avoid "Why doesn't this work?" type mail messages. However, active
  21. testing and use of these systems is welcomed. Just be aware that it
  22. may not meet the normal level of reliability or it may fail to work
  23. in some special cases. Detailed bug reports from people familiar
  24. with the kernel internals are usually welcomed by the developers
  25. (before submitting bug reports, please read the documents
  26. <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
  27. <file:Documentation/BUG-HUNTING>, and
  28. <file:Documentation/oops-tracing.txt> in the kernel source).
  29. This option will also make obsoleted drivers available. These are
  30. drivers that have been replaced by something else, and/or are
  31. scheduled to be removed in a future kernel release.
  32. Unless you intend to help test and develop a feature or driver that
  33. falls into this category, or you have a situation that requires
  34. using these features, you should probably say N here, which will
  35. cause the configurator to present you with fewer choices. If
  36. you say Y here, you will be offered the choice of using features or
  37. drivers that are currently considered to be in the alpha-test phase.
  38. config BROKEN
  39. bool
  40. config BROKEN_ON_SMP
  41. bool
  42. depends on BROKEN || !SMP
  43. default y
  44. config LOCK_KERNEL
  45. bool
  46. depends on SMP || PREEMPT
  47. default y
  48. config INIT_ENV_ARG_LIMIT
  49. int
  50. default 32 if !UML
  51. default 128 if UML
  52. help
  53. Maximum of each of the number of arguments and environment
  54. variables passed to init from the kernel command line.
  55. endmenu
  56. menu "General setup"
  57. config LOCALVERSION
  58. string "Local version - append to kernel release"
  59. help
  60. Append an extra string to the end of your kernel version.
  61. This will show up when you type uname, for example.
  62. The string you set here will be appended after the contents of
  63. any files with a filename matching localversion* in your
  64. object and source tree, in that order. Your total string can
  65. be a maximum of 64 characters.
  66. config LOCALVERSION_AUTO
  67. bool "Automatically append version information to the version string"
  68. default y
  69. help
  70. This will try to automatically determine if the current tree is a
  71. release tree by looking for git tags that
  72. belong to the current top of tree revision.
  73. A string of the format -gxxxxxxxx will be added to the localversion
  74. if a git based tree is found. The string generated by this will be
  75. appended after any matching localversion* files, and after the value
  76. set in CONFIG_LOCALVERSION
  77. Note: This requires Perl, and a git repository, but not necessarily
  78. the git or cogito tools to be installed.
  79. config SWAP
  80. bool "Support for paging of anonymous memory (swap)"
  81. depends on MMU && BLOCK
  82. default y
  83. help
  84. This option allows you to choose whether you want to have support
  85. for so called swap devices or swap files in your kernel that are
  86. used to provide more virtual memory than the actual RAM present
  87. in your computer. If unsure say Y.
  88. config SYSVIPC
  89. bool "System V IPC"
  90. ---help---
  91. Inter Process Communication is a suite of library functions and
  92. system calls which let processes (running programs) synchronize and
  93. exchange information. It is generally considered to be a good thing,
  94. and some programs won't run unless you say Y here. In particular, if
  95. you want to run the DOS emulator dosemu under Linux (read the
  96. DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
  97. you'll need to say Y here.
  98. You can find documentation about IPC with "info ipc" and also in
  99. section 6.4 of the Linux Programmer's Guide, available from
  100. <http://www.tldp.org/guides.html>.
  101. config IPC_NS
  102. bool "IPC Namespaces"
  103. depends on SYSVIPC
  104. default n
  105. help
  106. Support ipc namespaces. This allows containers, i.e. virtual
  107. environments, to use ipc namespaces to provide different ipc
  108. objects for different servers. If unsure, say N.
  109. config SYSVIPC_SYSCTL
  110. bool
  111. depends on SYSVIPC
  112. depends on SYSCTL
  113. default y
  114. config POSIX_MQUEUE
  115. bool "POSIX Message Queues"
  116. depends on NET && EXPERIMENTAL
  117. ---help---
  118. POSIX variant of message queues is a part of IPC. In POSIX message
  119. queues every message has a priority which decides about succession
  120. of receiving it by a process. If you want to compile and run
  121. programs written e.g. for Solaris with use of its POSIX message
  122. queues (functions mq_*) say Y here. To use this feature you will
  123. also need mqueue library, available from
  124. <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
  125. POSIX message queues are visible as a filesystem called 'mqueue'
  126. and can be mounted somewhere if you want to do filesystem
  127. operations on message queues.
  128. If unsure, say Y.
  129. config BSD_PROCESS_ACCT
  130. bool "BSD Process Accounting"
  131. help
  132. If you say Y here, a user level program will be able to instruct the
  133. kernel (via a special system call) to write process accounting
  134. information to a file: whenever a process exits, information about
  135. that process will be appended to the file by the kernel. The
  136. information includes things such as creation time, owning user,
  137. command name, memory usage, controlling terminal etc. (the complete
  138. list is in the struct acct in <file:include/linux/acct.h>). It is
  139. up to the user level program to do useful things with this
  140. information. This is generally a good idea, so say Y.
  141. config BSD_PROCESS_ACCT_V3
  142. bool "BSD Process Accounting version 3 file format"
  143. depends on BSD_PROCESS_ACCT
  144. default n
  145. help
  146. If you say Y here, the process accounting information is written
  147. in a new file format that also logs the process IDs of each
  148. process and it's parent. Note that this file format is incompatible
  149. with previous v0/v1/v2 file formats, so you will need updated tools
  150. for processing it. A preliminary version of these tools is available
  151. at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
  152. config TASKSTATS
  153. bool "Export task/process statistics through netlink (EXPERIMENTAL)"
  154. depends on NET
  155. default n
  156. help
  157. Export selected statistics for tasks/processes through the
  158. generic netlink interface. Unlike BSD process accounting, the
  159. statistics are available during the lifetime of tasks/processes as
  160. responses to commands. Like BSD accounting, they are sent to user
  161. space on task exit.
  162. Say N if unsure.
  163. config TASK_DELAY_ACCT
  164. bool "Enable per-task delay accounting (EXPERIMENTAL)"
  165. depends on TASKSTATS
  166. help
  167. Collect information on time spent by a task waiting for system
  168. resources like cpu, synchronous block I/O completion and swapping
  169. in pages. Such statistics can help in setting a task's priorities
  170. relative to other tasks for cpu, io, rss limits etc.
  171. Say N if unsure.
  172. config TASK_XACCT
  173. bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
  174. depends on TASKSTATS
  175. help
  176. Collect extended task accounting data and send the data
  177. to userland for processing over the taskstats interface.
  178. Say N if unsure.
  179. config TASK_IO_ACCOUNTING
  180. bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
  181. depends on TASK_XACCT
  182. help
  183. Collect information on the number of bytes of storage I/O which this
  184. task has caused.
  185. Say N if unsure.
  186. config UTS_NS
  187. bool "UTS Namespaces"
  188. default n
  189. help
  190. Support uts namespaces. This allows containers, i.e.
  191. vservers, to use uts namespaces to provide different
  192. uts info for different servers. If unsure, say N.
  193. config AUDIT
  194. bool "Auditing support"
  195. depends on NET
  196. help
  197. Enable auditing infrastructure that can be used with another
  198. kernel subsystem, such as SELinux (which requires this for
  199. logging of avc messages output). Does not do system-call
  200. auditing without CONFIG_AUDITSYSCALL.
  201. config AUDITSYSCALL
  202. bool "Enable system-call auditing support"
  203. depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
  204. default y if SECURITY_SELINUX
  205. help
  206. Enable low-overhead system-call auditing infrastructure that
  207. can be used independently or with another kernel subsystem,
  208. such as SELinux. To use audit's filesystem watch feature, please
  209. ensure that INOTIFY is configured.
  210. config IKCONFIG
  211. tristate "Kernel .config support"
  212. ---help---
  213. This option enables the complete Linux kernel ".config" file
  214. contents to be saved in the kernel. It provides documentation
  215. of which kernel options are used in a running kernel or in an
  216. on-disk kernel. This information can be extracted from the kernel
  217. image file with the script scripts/extract-ikconfig and used as
  218. input to rebuild the current kernel or to build another kernel.
  219. It can also be extracted from a running kernel by reading
  220. /proc/config.gz if enabled (below).
  221. config IKCONFIG_PROC
  222. bool "Enable access to .config through /proc/config.gz"
  223. depends on IKCONFIG && PROC_FS
  224. ---help---
  225. This option enables access to the kernel configuration file
  226. through /proc/config.gz.
  227. config CPUSETS
  228. bool "Cpuset support"
  229. depends on SMP
  230. help
  231. This option will let you create and manage CPUSETs which
  232. allow dynamically partitioning a system into sets of CPUs and
  233. Memory Nodes and assigning tasks to run only within those sets.
  234. This is primarily useful on large SMP or NUMA systems.
  235. Say N if unsure.
  236. config SYSFS_DEPRECATED
  237. bool "Create deprecated sysfs files"
  238. default y
  239. help
  240. This option creates deprecated symlinks such as the
  241. "device"-link, the <subsystem>:<name>-link, and the
  242. "bus"-link. It may also add deprecated key in the
  243. uevent environment.
  244. None of these features or values should be used today, as
  245. they export driver core implementation details to userspace
  246. or export properties which can't be kept stable across kernel
  247. releases.
  248. If enabled, this option will also move any device structures
  249. that belong to a class, back into the /sys/class heirachy, in
  250. order to support older versions of udev.
  251. If you are using a distro that was released in 2006 or later,
  252. it should be safe to say N here.
  253. config RELAY
  254. bool "Kernel->user space relay support (formerly relayfs)"
  255. help
  256. This option enables support for relay interface support in
  257. certain file systems (such as debugfs).
  258. It is designed to provide an efficient mechanism for tools and
  259. facilities to relay large amounts of data from kernel space to
  260. user space.
  261. If unsure, say N.
  262. if BLK_DEV_INITRD
  263. source "usr/Kconfig"
  264. endif
  265. config CC_OPTIMIZE_FOR_SIZE
  266. bool "Optimize for size (Look out for broken compilers!)"
  267. default y
  268. depends on ARM || H8300 || EXPERIMENTAL
  269. help
  270. Enabling this option will pass "-Os" instead of "-O2" to gcc
  271. resulting in a smaller kernel.
  272. WARNING: some versions of gcc may generate incorrect code with this
  273. option. If problems are observed, a gcc upgrade may be needed.
  274. If unsure, say N.
  275. config SYSCTL
  276. bool
  277. menuconfig EMBEDDED
  278. bool "Configure standard kernel features (for small systems)"
  279. help
  280. This option allows certain base kernel options and settings
  281. to be disabled or tweaked. This is for specialized
  282. environments which can tolerate a "non-standard" kernel.
  283. Only use this if you really know what you are doing.
  284. config UID16
  285. bool "Enable 16-bit UID system calls" if EMBEDDED
  286. depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
  287. default y
  288. help
  289. This enables the legacy 16-bit UID syscall wrappers.
  290. config SYSCTL_SYSCALL
  291. bool "Sysctl syscall support" if EMBEDDED
  292. default y
  293. select SYSCTL
  294. ---help---
  295. sys_sysctl uses binary paths that have been found challenging
  296. to properly maintain and use. The interface in /proc/sys
  297. using paths with ascii names is now the primary path to this
  298. information.
  299. Almost nothing using the binary sysctl interface so if you are
  300. trying to save some space it is probably safe to disable this,
  301. making your kernel marginally smaller.
  302. If unsure say Y here.
  303. config KALLSYMS
  304. bool "Load all symbols for debugging/ksymoops" if EMBEDDED
  305. default y
  306. help
  307. Say Y here to let the kernel print out symbolic crash information and
  308. symbolic stack backtraces. This increases the size of the kernel
  309. somewhat, as all symbols have to be loaded into the kernel image.
  310. config KALLSYMS_ALL
  311. bool "Include all symbols in kallsyms"
  312. depends on DEBUG_KERNEL && KALLSYMS
  313. help
  314. Normally kallsyms only contains the symbols of functions, for nicer
  315. OOPS messages. Some debuggers can use kallsyms for other
  316. symbols too: say Y here to include all symbols, if you need them
  317. and you don't care about adding 300k to the size of your kernel.
  318. Say N.
  319. config KALLSYMS_EXTRA_PASS
  320. bool "Do an extra kallsyms pass"
  321. depends on KALLSYMS
  322. help
  323. If kallsyms is not working correctly, the build will fail with
  324. inconsistent kallsyms data. If that occurs, log a bug report and
  325. turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
  326. Always say N here unless you find a bug in kallsyms, which must be
  327. reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
  328. you wait for kallsyms to be fixed.
  329. config HOTPLUG
  330. bool "Support for hot-pluggable devices" if EMBEDDED
  331. default y
  332. help
  333. This option is provided for the case where no hotplug or uevent
  334. capabilities is wanted by the kernel. You should only consider
  335. disabling this option for embedded systems that do not use modules, a
  336. dynamic /dev tree, or dynamic device discovery. Just say Y.
  337. config PRINTK
  338. default y
  339. bool "Enable support for printk" if EMBEDDED
  340. help
  341. This option enables normal printk support. Removing it
  342. eliminates most of the message strings from the kernel image
  343. and makes the kernel more or less silent. As this makes it
  344. very difficult to diagnose system problems, saying N here is
  345. strongly discouraged.
  346. config BUG
  347. bool "BUG() support" if EMBEDDED
  348. default y
  349. help
  350. Disabling this option eliminates support for BUG and WARN, reducing
  351. the size of your kernel image and potentially quietly ignoring
  352. numerous fatal conditions. You should only consider disabling this
  353. option for embedded systems with no facilities for reporting errors.
  354. Just say Y.
  355. config ELF_CORE
  356. default y
  357. bool "Enable ELF core dumps" if EMBEDDED
  358. help
  359. Enable support for generating core dumps. Disabling saves about 4k.
  360. config BASE_FULL
  361. default y
  362. bool "Enable full-sized data structures for core" if EMBEDDED
  363. help
  364. Disabling this option reduces the size of miscellaneous core
  365. kernel data structures. This saves memory on small machines,
  366. but may reduce performance.
  367. config FUTEX
  368. bool "Enable futex support" if EMBEDDED
  369. default y
  370. select RT_MUTEXES
  371. help
  372. Disabling this option will cause the kernel to be built without
  373. support for "fast userspace mutexes". The resulting kernel may not
  374. run glibc-based applications correctly.
  375. config EPOLL
  376. bool "Enable eventpoll support" if EMBEDDED
  377. default y
  378. help
  379. Disabling this option will cause the kernel to be built without
  380. support for epoll family of system calls.
  381. config SHMEM
  382. bool "Use full shmem filesystem" if EMBEDDED
  383. default y
  384. depends on MMU
  385. help
  386. The shmem is an internal filesystem used to manage shared memory.
  387. It is backed by swap and manages resource limits. It is also exported
  388. to userspace as tmpfs if TMPFS is enabled. Disabling this
  389. option replaces shmem and tmpfs with the much simpler ramfs code,
  390. which may be appropriate on small systems without swap.
  391. config SLAB
  392. default y
  393. bool "Use full SLAB allocator" if (EMBEDDED && !SMP && !SPARSEMEM)
  394. help
  395. Disabling this replaces the advanced SLAB allocator and
  396. kmalloc support with the drastically simpler SLOB allocator.
  397. SLOB is more space efficient but does not scale well and is
  398. more susceptible to fragmentation.
  399. config VM_EVENT_COUNTERS
  400. default y
  401. bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
  402. help
  403. VM event counters are needed for event counts to be shown.
  404. This option allows the disabling of the VM event counters
  405. on EMBEDDED systems. /proc/vmstat will only show page counts
  406. if VM event counters are disabled.
  407. endmenu # General setup
  408. config RT_MUTEXES
  409. boolean
  410. select PLIST
  411. config TINY_SHMEM
  412. default !SHMEM
  413. bool
  414. config BASE_SMALL
  415. int
  416. default 0 if BASE_FULL
  417. default 1 if !BASE_FULL
  418. config SLOB
  419. default !SLAB
  420. bool
  421. menu "Loadable module support"
  422. config MODULES
  423. bool "Enable loadable module support"
  424. help
  425. Kernel modules are small pieces of compiled code which can
  426. be inserted in the running kernel, rather than being
  427. permanently built into the kernel. You use the "modprobe"
  428. tool to add (and sometimes remove) them. If you say Y here,
  429. many parts of the kernel can be built as modules (by
  430. answering M instead of Y where indicated): this is most
  431. useful for infrequently used options which are not required
  432. for booting. For more information, see the man pages for
  433. modprobe, lsmod, modinfo, insmod and rmmod.
  434. If you say Y here, you will need to run "make
  435. modules_install" to put the modules under /lib/modules/
  436. where modprobe can find them (you may need to be root to do
  437. this).
  438. If unsure, say Y.
  439. config MODULE_UNLOAD
  440. bool "Module unloading"
  441. depends on MODULES
  442. help
  443. Without this option you will not be able to unload any
  444. modules (note that some modules may not be unloadable
  445. anyway), which makes your kernel slightly smaller and
  446. simpler. If unsure, say Y.
  447. config MODULE_FORCE_UNLOAD
  448. bool "Forced module unloading"
  449. depends on MODULE_UNLOAD && EXPERIMENTAL
  450. help
  451. This option allows you to force a module to unload, even if the
  452. kernel believes it is unsafe: the kernel will remove the module
  453. without waiting for anyone to stop using it (using the -f option to
  454. rmmod). This is mainly for kernel developers and desperate users.
  455. If unsure, say N.
  456. config MODVERSIONS
  457. bool "Module versioning support"
  458. depends on MODULES
  459. help
  460. Usually, you have to use modules compiled with your kernel.
  461. Saying Y here makes it sometimes possible to use modules
  462. compiled for different kernels, by adding enough information
  463. to the modules to (hopefully) spot any changes which would
  464. make them incompatible with the kernel you are running. If
  465. unsure, say N.
  466. config MODULE_SRCVERSION_ALL
  467. bool "Source checksum for all modules"
  468. depends on MODULES
  469. help
  470. Modules which contain a MODULE_VERSION get an extra "srcversion"
  471. field inserted into their modinfo section, which contains a
  472. sum of the source files which made it. This helps maintainers
  473. see exactly which source was used to build a module (since
  474. others sometimes change the module source without updating
  475. the version). With this option, such a "srcversion" field
  476. will be created for all modules. If unsure, say N.
  477. config KMOD
  478. bool "Automatic kernel module loading"
  479. depends on MODULES
  480. help
  481. Normally when you have selected some parts of the kernel to
  482. be created as kernel modules, you must load them (using the
  483. "modprobe" command) before you can use them. If you say Y
  484. here, some parts of the kernel will be able to load modules
  485. automatically: when a part of the kernel needs a module, it
  486. runs modprobe with the appropriate arguments, thereby
  487. loading the module if it is available. If unsure, say Y.
  488. config STOP_MACHINE
  489. bool
  490. default y
  491. depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
  492. help
  493. Need stop_machine() primitive.
  494. endmenu
  495. menu "Block layer"
  496. source "block/Kconfig"
  497. endmenu