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 drivers that have been replaced by something else, and/or are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