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33 drivers that have been replaced by something else, and/or are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