| blob | ebe04f56d8343b980814b5ee551cc7f62242e282 |
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"
10 menu "Code maturity level options"
12 config EXPERIMENTAL
13 bool "Prompt for development and/or incomplete code/drivers"
14 ---help---
15 Some of the various things that Linux supports (such as network
16 drivers, file systems, network protocols, etc.) can be in a state
17 of development where the functionality, stability, or the level of
18 testing is not yet high enough for general use. This is usually
19 known as the "alpha-test" phase among developers. If a feature is
20 currently in alpha-test, then the developers usually discourage
21 uninformed widespread use of this feature by the general public to
22 avoid "Why doesn't this work?" type mail messages. However, active
23 testing and use of these systems is welcomed. Just be aware that it
24 may not meet the normal level of reliability or it may fail to work
25 in some special cases. Detailed bug reports from people familiar
26 with the kernel internals are usually welcomed by the developers
27 (before submitting bug reports, please read the documents
28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
29 <file:Documentation/BUG-HUNTING>, and
30 <file:Documentation/oops-tracing.txt> in the kernel source).
32 This option will also make obsoleted drivers available. These are
33 drivers that have been replaced by something else, and/or are
34 scheduled to be removed in a future kernel release.
36 Unless you intend to help test and develop a feature or driver that
37 falls into this category, or you have a situation that requires
38 using these features, you should probably say N here, which will
39 cause the configurator to present you with fewer choices. If
40 you say Y here, you will be offered the choice of using features or
41 drivers that are currently considered to be in the alpha-test phase.
43 config BROKEN
44 bool
46 config BROKEN_ON_SMP
47 bool
48 depends on BROKEN || !SMP
49 default y
51 config LOCK_KERNEL
52 bool
53 depends on SMP || PREEMPT
54 default y
56 config INIT_ENV_ARG_LIMIT
57 int
58 default 32 if !UML
59 default 128 if UML
60 help
61 Maximum of each of the number of arguments and environment
62 variables passed to init from the kernel command line.
64 endmenu
66 menu "General setup"
68 config LOCALVERSION
69 string "Local version - append to kernel release"
70 help
71 Append an extra string to the end of your kernel version.
72 This will show up when you type uname, for example.
73 The string you set here will be appended after the contents of
74 any files with a filename matching localversion* in your
75 object and source tree, in that order. Your total string can
76 be a maximum of 64 characters.
78 config LOCALVERSION_AUTO
79 bool "Automatically append version information to the version string"
80 default y
81 help
82 This will try to automatically determine if the current tree is a
83 release tree by looking for git tags that belong to the current
84 top of tree revision.
86 A string of the format -gxxxxxxxx will be added to the localversion
87 if a git-based tree is found. The string generated by this will be
88 appended after any matching localversion* files, and after the value
89 set in CONFIG_LOCALVERSION.
91 (The actual string used here is the first eight characters produced
92 by running the command:
94 $ git rev-parse --verify HEAD
96 which is done within the script "scripts/setlocalversion".)
98 config SWAP
99 bool "Support for paging of anonymous memory (swap)"
100 depends on MMU && BLOCK
101 default y
102 help
103 This option allows you to choose whether you want to have support
104 for so called swap devices or swap files in your kernel that are
105 used to provide more virtual memory than the actual RAM present
106 in your computer. If unsure say Y.
108 config SYSVIPC
109 bool "System V IPC"
110 ---help---
111 Inter Process Communication is a suite of library functions and
112 system calls which let processes (running programs) synchronize and
113 exchange information. It is generally considered to be a good thing,
114 and some programs won't run unless you say Y here. In particular, if
115 you want to run the DOS emulator dosemu under Linux (read the
116 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
117 you'll need to say Y here.
119 You can find documentation about IPC with "info ipc" and also in
120 section 6.4 of the Linux Programmer's Guide, available from
121 <http://www.tldp.org/guides.html>.
123 config IPC_NS
124 bool "IPC Namespaces"
125 depends on SYSVIPC
126 default n
127 help
128 Support ipc namespaces. This allows containers, i.e. virtual
129 environments, to use ipc namespaces to provide different ipc
130 objects for different servers. If unsure, say N.
132 config SYSVIPC_SYSCTL
133 bool
134 depends on SYSVIPC
135 depends on SYSCTL
136 default y
138 config POSIX_MQUEUE
139 bool "POSIX Message Queues"
140 depends on NET && EXPERIMENTAL
141 ---help---
142 POSIX variant of message queues is a part of IPC. In POSIX message
143 queues every message has a priority which decides about succession
144 of receiving it by a process. If you want to compile and run
145 programs written e.g. for Solaris with use of its POSIX message
146 queues (functions mq_*) say Y here. To use this feature you will
147 also need mqueue library, available from
148 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
150 POSIX message queues are visible as a filesystem called 'mqueue'
151 and can be mounted somewhere if you want to do filesystem
152 operations on message queues.
154 If unsure, say Y.
156 config BSD_PROCESS_ACCT
157 bool "BSD Process Accounting"
158 help
159 If you say Y here, a user level program will be able to instruct the
160 kernel (via a special system call) to write process accounting
161 information to a file: whenever a process exits, information about
162 that process will be appended to the file by the kernel. The
163 information includes things such as creation time, owning user,
164 command name, memory usage, controlling terminal etc. (the complete
165 list is in the struct acct in <file:include/linux/acct.h>). It is
166 up to the user level program to do useful things with this
167 information. This is generally a good idea, so say Y.
169 config BSD_PROCESS_ACCT_V3
170 bool "BSD Process Accounting version 3 file format"
171 depends on BSD_PROCESS_ACCT
172 default n
173 help
174 If you say Y here, the process accounting information is written
175 in a new file format that also logs the process IDs of each
176 process and it's parent. Note that this file format is incompatible
177 with previous v0/v1/v2 file formats, so you will need updated tools
178 for processing it. A preliminary version of these tools is available
179 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
181 config TASKSTATS
182 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
183 depends on NET
184 default n
185 help
186 Export selected statistics for tasks/processes through the
187 generic netlink interface. Unlike BSD process accounting, the
188 statistics are available during the lifetime of tasks/processes as
189 responses to commands. Like BSD accounting, they are sent to user
190 space on task exit.
192 Say N if unsure.
194 config TASK_DELAY_ACCT
195 bool "Enable per-task delay accounting (EXPERIMENTAL)"
196 depends on TASKSTATS
197 help
198 Collect information on time spent by a task waiting for system
199 resources like cpu, synchronous block I/O completion and swapping
200 in pages. Such statistics can help in setting a task's priorities
201 relative to other tasks for cpu, io, rss limits etc.
203 Say N if unsure.
205 config TASK_XACCT
206 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
207 depends on TASKSTATS
208 help
209 Collect extended task accounting data and send the data
210 to userland for processing over the taskstats interface.
212 Say N if unsure.
214 config TASK_IO_ACCOUNTING
215 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
216 depends on TASK_XACCT
217 help
218 Collect information on the number of bytes of storage I/O which this
219 task has caused.
221 Say N if unsure.
223 config UTS_NS
224 bool "UTS Namespaces"
225 default n
226 help
227 Support uts namespaces. This allows containers, i.e.
228 vservers, to use uts namespaces to provide different
229 uts info for different servers. If unsure, say N.
231 config AUDIT
232 bool "Auditing support"
233 depends on NET
234 help
235 Enable auditing infrastructure that can be used with another
236 kernel subsystem, such as SELinux (which requires this for
237 logging of avc messages output). Does not do system-call
238 auditing without CONFIG_AUDITSYSCALL.
240 config AUDITSYSCALL
241 bool "Enable system-call auditing support"
242 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
243 default y if SECURITY_SELINUX
244 help
245 Enable low-overhead system-call auditing infrastructure that
246 can be used independently or with another kernel subsystem,
247 such as SELinux. To use audit's filesystem watch feature, please
248 ensure that INOTIFY is configured.
250 config IKCONFIG
251 tristate "Kernel .config support"
252 ---help---
253 This option enables the complete Linux kernel ".config" file
254 contents to be saved in the kernel. It provides documentation
255 of which kernel options are used in a running kernel or in an
256 on-disk kernel. This information can be extracted from the kernel
257 image file with the script scripts/extract-ikconfig and used as
258 input to rebuild the current kernel or to build another kernel.
259 It can also be extracted from a running kernel by reading
260 /proc/config.gz if enabled (below).
262 config IKCONFIG_PROC
263 bool "Enable access to .config through /proc/config.gz"
264 depends on IKCONFIG && PROC_FS
265 ---help---
266 This option enables access to the kernel configuration file
267 through /proc/config.gz.
269 config CPUSETS
270 bool "Cpuset support"
271 depends on SMP
272 help
273 This option will let you create and manage CPUSETs which
274 allow dynamically partitioning a system into sets of CPUs and
275 Memory Nodes and assigning tasks to run only within those sets.
276 This is primarily useful on large SMP or NUMA systems.
278 Say N if unsure.
280 config SYSFS_DEPRECATED
281 bool "Create deprecated sysfs files"
282 default y
283 help
284 This option creates deprecated symlinks such as the
285 "device"-link, the <subsystem>:<name>-link, and the
286 "bus"-link. It may also add deprecated key in the
287 uevent environment.
288 None of these features or values should be used today, as
289 they export driver core implementation details to userspace
290 or export properties which can't be kept stable across kernel
291 releases.
293 If enabled, this option will also move any device structures
294 that belong to a class, back into the /sys/class heirachy, in
295 order to support older versions of udev.
297 If you are using a distro that was released in 2006 or later,
298 it should be safe to say N here.
300 config RELAY
301 bool "Kernel->user space relay support (formerly relayfs)"
302 help
303 This option enables support for relay interface support in
304 certain file systems (such as debugfs).
305 It is designed to provide an efficient mechanism for tools and
306 facilities to relay large amounts of data from kernel space to
307 user space.
309 If unsure, say N.
311 config BLK_DEV_INITRD
312 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
313 depends on BROKEN || !FRV
314 help
315 The initial RAM filesystem is a ramfs which is loaded by the
316 boot loader (loadlin or lilo) and that is mounted as root
317 before the normal boot procedure. It is typically used to
318 load modules needed to mount the "real" root file system,
319 etc. See <file:Documentation/initrd.txt> for details.
321 If RAM disk support (BLK_DEV_RAM) is also included, this
322 also enables initial RAM disk (initrd) support and adds
323 15 Kbytes (more on some other architectures) to the kernel size.
325 If unsure say Y.
327 if BLK_DEV_INITRD
329 source "usr/Kconfig"
331 endif
333 config CC_OPTIMIZE_FOR_SIZE
334 bool "Optimize for size (Look out for broken compilers!)"
335 default y
336 depends on ARM || H8300 || EXPERIMENTAL
337 help
338 Enabling this option will pass "-Os" instead of "-O2" to gcc
339 resulting in a smaller kernel.
341 WARNING: some versions of gcc may generate incorrect code with this
342 option. If problems are observed, a gcc upgrade may be needed.
344 If unsure, say N.
346 config SYSCTL
347 bool
349 menuconfig EMBEDDED
350 bool "Configure standard kernel features (for small systems)"
351 help
352 This option allows certain base kernel options and settings
353 to be disabled or tweaked. This is for specialized
354 environments which can tolerate a "non-standard" kernel.
355 Only use this if you really know what you are doing.
357 config UID16
358 bool "Enable 16-bit UID system calls" if EMBEDDED
359 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
360 default y
361 help
362 This enables the legacy 16-bit UID syscall wrappers.
364 config SYSCTL_SYSCALL
365 bool "Sysctl syscall support" if EMBEDDED
366 default y
367 select SYSCTL
368 ---help---
369 sys_sysctl uses binary paths that have been found challenging
370 to properly maintain and use. The interface in /proc/sys
371 using paths with ascii names is now the primary path to this
372 information.
374 Almost nothing using the binary sysctl interface so if you are
375 trying to save some space it is probably safe to disable this,
376 making your kernel marginally smaller.
378 If unsure say Y here.
380 config KALLSYMS
381 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
382 default y
383 help
384 Say Y here to let the kernel print out symbolic crash information and
385 symbolic stack backtraces. This increases the size of the kernel
386 somewhat, as all symbols have to be loaded into the kernel image.
388 config KALLSYMS_ALL
389 bool "Include all symbols in kallsyms"
390 depends on DEBUG_KERNEL && KALLSYMS
391 help
392 Normally kallsyms only contains the symbols of functions, for nicer
393 OOPS messages. Some debuggers can use kallsyms for other
394 symbols too: say Y here to include all symbols, if you need them
395 and you don't care about adding 300k to the size of your kernel.
397 Say N.
399 config KALLSYMS_EXTRA_PASS
400 bool "Do an extra kallsyms pass"
401 depends on KALLSYMS
402 help
403 If kallsyms is not working correctly, the build will fail with
404 inconsistent kallsyms data. If that occurs, log a bug report and
405 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
406 Always say N here unless you find a bug in kallsyms, which must be
407 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
408 you wait for kallsyms to be fixed.
411 config HOTPLUG
412 bool "Support for hot-pluggable devices" if EMBEDDED
413 default y
414 help
415 This option is provided for the case where no hotplug or uevent
416 capabilities is wanted by the kernel. You should only consider
417 disabling this option for embedded systems that do not use modules, a
418 dynamic /dev tree, or dynamic device discovery. Just say Y.
420 config PRINTK
421 default y
422 bool "Enable support for printk" if EMBEDDED
423 help
424 This option enables normal printk support. Removing it
425 eliminates most of the message strings from the kernel image
426 and makes the kernel more or less silent. As this makes it
427 very difficult to diagnose system problems, saying N here is
428 strongly discouraged.
430 config BUG
431 bool "BUG() support" if EMBEDDED
432 default y
433 help
434 Disabling this option eliminates support for BUG and WARN, reducing
435 the size of your kernel image and potentially quietly ignoring
436 numerous fatal conditions. You should only consider disabling this
437 option for embedded systems with no facilities for reporting errors.
438 Just say Y.
440 config ELF_CORE
441 default y
442 bool "Enable ELF core dumps" if EMBEDDED
443 help
444 Enable support for generating core dumps. Disabling saves about 4k.
446 config BASE_FULL
447 default y
448 bool "Enable full-sized data structures for core" if EMBEDDED
449 help
450 Disabling this option reduces the size of miscellaneous core
451 kernel data structures. This saves memory on small machines,
452 but may reduce performance.
454 config FUTEX
455 bool "Enable futex support" if EMBEDDED
456 default y
457 select RT_MUTEXES
458 help
459 Disabling this option will cause the kernel to be built without
460 support for "fast userspace mutexes". The resulting kernel may not
461 run glibc-based applications correctly.
463 config EPOLL
464 bool "Enable eventpoll support" if EMBEDDED
465 default y
466 help
467 Disabling this option will cause the kernel to be built without
468 support for epoll family of system calls.
470 config SHMEM
471 bool "Use full shmem filesystem" if EMBEDDED
472 default y
473 depends on MMU
474 help
475 The shmem is an internal filesystem used to manage shared memory.
476 It is backed by swap and manages resource limits. It is also exported
477 to userspace as tmpfs if TMPFS is enabled. Disabling this
478 option replaces shmem and tmpfs with the much simpler ramfs code,
479 which may be appropriate on small systems without swap.
481 config VM_EVENT_COUNTERS
482 default y
483 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
484 help
485 VM event counters are needed for event counts to be shown.
486 This option allows the disabling of the VM event counters
487 on EMBEDDED systems. /proc/vmstat will only show page counts
488 if VM event counters are disabled.
490 choice
491 prompt "Choose SLAB allocator"
492 default SLAB
493 help
494 This option allows to select a slab allocator.
496 config SLAB
497 bool "SLAB"
498 help
499 The regular slab allocator that is established and known to work
500 well in all environments. It organizes chache hot objects in
501 per cpu and per node queues. SLAB is the default choice for
502 slab allocator.
504 config SLUB
505 depends on EXPERIMENTAL && !ARCH_USES_SLAB_PAGE_STRUCT
506 bool "SLUB (Unqueued Allocator)"
507 help
508 SLUB is a slab allocator that minimizes cache line usage
509 instead of managing queues of cached objects (SLAB approach).
510 Per cpu caching is realized using slabs of objects instead
511 of queues of objects. SLUB can use memory efficiently
512 way and has enhanced diagnostics.
514 config SLOB
515 #
516 # SLOB cannot support SMP because SLAB_DESTROY_BY_RCU does not work
517 # properly.
518 #
519 depends on EMBEDDED && !SMP && !SPARSEMEM
520 bool "SLOB (Simple Allocator)"
521 help
522 SLOB replaces the SLAB allocator with a drastically simpler
523 allocator. SLOB is more space efficient that SLAB but does not
524 scale well (single lock for all operations) and is more susceptible
525 to fragmentation. SLOB it is a great choice to reduce
526 memory usage and code size for embedded systems.
528 endchoice
530 endmenu # General setup
532 config RT_MUTEXES
533 boolean
534 select PLIST
536 config TINY_SHMEM
537 default !SHMEM
538 bool
540 config BASE_SMALL
541 int
542 default 0 if BASE_FULL
543 default 1 if !BASE_FULL
545 menu "Loadable module support"
547 config MODULES
548 bool "Enable loadable module support"
549 help
550 Kernel modules are small pieces of compiled code which can
551 be inserted in the running kernel, rather than being
552 permanently built into the kernel. You use the "modprobe"
553 tool to add (and sometimes remove) them. If you say Y here,
554 many parts of the kernel can be built as modules (by
555 answering M instead of Y where indicated): this is most
556 useful for infrequently used options which are not required
557 for booting. For more information, see the man pages for
558 modprobe, lsmod, modinfo, insmod and rmmod.
560 If you say Y here, you will need to run "make
561 modules_install" to put the modules under /lib/modules/
562 where modprobe can find them (you may need to be root to do
563 this).
565 If unsure, say Y.
567 config MODULE_UNLOAD
568 bool "Module unloading"
569 depends on MODULES
570 help
571 Without this option you will not be able to unload any
572 modules (note that some modules may not be unloadable
573 anyway), which makes your kernel slightly smaller and
574 simpler. If unsure, say Y.
576 config MODULE_FORCE_UNLOAD
577 bool "Forced module unloading"
578 depends on MODULE_UNLOAD && EXPERIMENTAL
579 help
580 This option allows you to force a module to unload, even if the
581 kernel believes it is unsafe: the kernel will remove the module
582 without waiting for anyone to stop using it (using the -f option to
583 rmmod). This is mainly for kernel developers and desperate users.
584 If unsure, say N.
586 config MODVERSIONS
587 bool "Module versioning support"
588 depends on MODULES
589 help
590 Usually, you have to use modules compiled with your kernel.
591 Saying Y here makes it sometimes possible to use modules
592 compiled for different kernels, by adding enough information
593 to the modules to (hopefully) spot any changes which would
594 make them incompatible with the kernel you are running. If
595 unsure, say N.
597 config MODULE_SRCVERSION_ALL
598 bool "Source checksum for all modules"
599 depends on MODULES
600 help
601 Modules which contain a MODULE_VERSION get an extra "srcversion"
602 field inserted into their modinfo section, which contains a
603 sum of the source files which made it. This helps maintainers
604 see exactly which source was used to build a module (since
605 others sometimes change the module source without updating
606 the version). With this option, such a "srcversion" field
607 will be created for all modules. If unsure, say N.
609 config KMOD
610 bool "Automatic kernel module loading"
611 depends on MODULES
612 help
613 Normally when you have selected some parts of the kernel to
614 be created as kernel modules, you must load them (using the
615 "modprobe" command) before you can use them. If you say Y
616 here, some parts of the kernel will be able to load modules
617 automatically: when a part of the kernel needs a module, it
618 runs modprobe with the appropriate arguments, thereby
619 loading the module if it is available. If unsure, say Y.
621 config STOP_MACHINE
622 bool
623 default y
624 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
625 help
626 Need stop_machine() primitive.
627 endmenu
629 menu "Block layer"
630 source "block/Kconfig"
631 endmenu