| blob | 3dcbd5bfd49843168d6b45f62d3ae5a7b8cfecdc |
1 menu "Code maturity level options"
3 config EXPERIMENTAL
4 bool "Prompt for development and/or incomplete code/drivers"
5 ---help---
6 Some of the various things that Linux supports (such as network
7 drivers, file systems, network protocols, etc.) can be in a state
8 of development where the functionality, stability, or the level of
9 testing is not yet high enough for general use. This is usually
10 known as the "alpha-test" phase among developers. If a feature is
11 currently in alpha-test, then the developers usually discourage
12 uninformed widespread use of this feature by the general public to
13 avoid "Why doesn't this work?" type mail messages. However, active
14 testing and use of these systems is welcomed. Just be aware that it
15 may not meet the normal level of reliability or it may fail to work
16 in some special cases. Detailed bug reports from people familiar
17 with the kernel internals are usually welcomed by the developers
18 (before submitting bug reports, please read the documents
19 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
20 <file:Documentation/BUG-HUNTING>, and
21 <file:Documentation/oops-tracing.txt> in the kernel source).
23 This option will also make obsoleted drivers available. These are
24 drivers that have been replaced by something else, and/or are
25 scheduled to be removed in a future kernel release.
27 Unless you intend to help test and develop a feature or driver that
28 falls into this category, or you have a situation that requires
29 using these features, you should probably say N here, which will
30 cause the configurator to present you with fewer choices. If
31 you say Y here, you will be offered the choice of using features or
32 drivers that are currently considered to be in the alpha-test phase.
34 config CLEAN_COMPILE
35 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
36 default y
37 help
38 Select this option if you don't even want to see the option
39 to configure known-broken drivers.
41 If unsure, say Y
43 config BROKEN
44 bool
45 depends on !CLEAN_COMPILE
46 default y
48 config BROKEN_ON_SMP
49 bool
50 depends on BROKEN || !SMP
51 default y
53 config LOCK_KERNEL
54 bool
55 depends on SMP || PREEMPT
56 default y
58 config INIT_ENV_ARG_LIMIT
59 int
60 default 32 if !USERMODE
61 default 128 if USERMODE
62 help
63 Maximum of each of the number of arguments and environment
64 variables passed to init from the kernel command line.
66 endmenu
68 menu "General setup"
70 config LOCALVERSION
71 string "Local version - append to kernel release"
72 help
73 Append an extra string to the end of your kernel version.
74 This will show up when you type uname, for example.
75 The string you set here will be appended after the contents of
76 any files with a filename matching localversion* in your
77 object and source tree, in that order. Your total string can
78 be a maximum of 64 characters.
80 config LOCALVERSION_AUTO
81 bool "Automatically append version information to the version string"
82 default y
83 help
84 This will try to automatically determine if the current tree is a
85 release tree by looking for git tags that
86 belong to the current top of tree revision.
88 A string of the format -gxxxxxxxx will be added to the localversion
89 if a git based tree is found. The string generated by this will be
90 appended after any matching localversion* files, and after the value
91 set in CONFIG_LOCALVERSION
93 Note: This requires Perl, and a git repository, but not necessarily
94 the git or cogito tools to be installed.
96 config SWAP
97 bool "Support for paging of anonymous memory (swap)"
98 depends on MMU
99 default y
100 help
101 This option allows you to choose whether you want to have support
102 for socalled swap devices or swap files in your kernel that are
103 used to provide more virtual memory than the actual RAM present
104 in your computer. If unsure say Y.
106 config SYSVIPC
107 bool "System V IPC"
108 depends on MMU
109 ---help---
110 Inter Process Communication is a suite of library functions and
111 system calls which let processes (running programs) synchronize and
112 exchange information. It is generally considered to be a good thing,
113 and some programs won't run unless you say Y here. In particular, if
114 you want to run the DOS emulator dosemu under Linux (read the
115 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
116 you'll need to say Y here.
118 You can find documentation about IPC with "info ipc" and also in
119 section 6.4 of the Linux Programmer's Guide, available from
120 <http://www.tldp.org/guides.html>.
122 config POSIX_MQUEUE
123 bool "POSIX Message Queues"
124 depends on NET && EXPERIMENTAL
125 ---help---
126 POSIX variant of message queues is a part of IPC. In POSIX message
127 queues every message has a priority which decides about succession
128 of receiving it by a process. If you want to compile and run
129 programs written e.g. for Solaris with use of its POSIX message
130 queues (functions mq_*) say Y here. To use this feature you will
131 also need mqueue library, available from
132 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
134 POSIX message queues are visible as a filesystem called 'mqueue'
135 and can be mounted somewhere if you want to do filesystem
136 operations on message queues.
138 If unsure, say Y.
140 config BSD_PROCESS_ACCT
141 bool "BSD Process Accounting"
142 help
143 If you say Y here, a user level program will be able to instruct the
144 kernel (via a special system call) to write process accounting
145 information to a file: whenever a process exits, information about
146 that process will be appended to the file by the kernel. The
147 information includes things such as creation time, owning user,
148 command name, memory usage, controlling terminal etc. (the complete
149 list is in the struct acct in <file:include/linux/acct.h>). It is
150 up to the user level program to do useful things with this
151 information. This is generally a good idea, so say Y.
153 config BSD_PROCESS_ACCT_V3
154 bool "BSD Process Accounting version 3 file format"
155 depends on BSD_PROCESS_ACCT
156 default n
157 help
158 If you say Y here, the process accounting information is written
159 in a new file format that also logs the process IDs of each
160 process and it's parent. Note that this file format is incompatible
161 with previous v0/v1/v2 file formats, so you will need updated tools
162 for processing it. A preliminary version of these tools is available
163 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
165 config SYSCTL
166 bool "Sysctl support"
167 ---help---
168 The sysctl interface provides a means of dynamically changing
169 certain kernel parameters and variables on the fly without requiring
170 a recompile of the kernel or reboot of the system. The primary
171 interface consists of a system call, but if you say Y to "/proc
172 file system support", a tree of modifiable sysctl entries will be
173 generated beneath the /proc/sys directory. They are explained in the
174 files in <file:Documentation/sysctl/>. Note that enabling this
175 option will enlarge the kernel by at least 8 KB.
177 As it is generally a good thing, you should say Y here unless
178 building a kernel for install/rescue disks or your system is very
179 limited in memory.
181 config AUDIT
182 bool "Auditing support"
183 depends on NET
184 default y if SECURITY_SELINUX
185 help
186 Enable auditing infrastructure that can be used with another
187 kernel subsystem, such as SELinux (which requires this for
188 logging of avc messages output). Does not do system-call
189 auditing without CONFIG_AUDITSYSCALL.
191 config AUDITSYSCALL
192 bool "Enable system-call auditing support"
193 depends on AUDIT && (X86 || PPC || PPC64 || ARCH_S390 || IA64 || UML || SPARC64)
194 default y if SECURITY_SELINUX
195 help
196 Enable low-overhead system-call auditing infrastructure that
197 can be used independently or with another kernel subsystem,
198 such as SELinux.
200 config HOTPLUG
201 bool "Support for hot-pluggable devices" if !ARCH_S390
202 default ARCH_S390
203 help
204 This option is provided for the case where no in-kernel-tree
205 modules require HOTPLUG functionality, but a module built
206 outside the kernel tree does. Such modules require Y here.
208 config KOBJECT_UEVENT
209 bool "Kernel Userspace Events"
210 depends on NET
211 default y
212 help
213 This option enables the kernel userspace event layer, which is a
214 simple mechanism for kernel-to-user communication over a netlink
215 socket.
216 The goal of the kernel userspace events layer is to provide a simple
217 and efficient events system, that notifies userspace about kobject
218 state changes. This will enable applications to just listen for
219 events instead of polling system devices and files.
220 Hotplug events (kobject addition and removal) are also available on
221 the netlink socket in addition to the execution of /sbin/hotplug if
222 CONFIG_HOTPLUG is enabled.
224 Say Y, unless you are building a system requiring minimal memory
225 consumption.
227 config IKCONFIG
228 bool "Kernel .config support"
229 ---help---
230 This option enables the complete Linux kernel ".config" file
231 contents to be saved in the kernel. It provides documentation
232 of which kernel options are used in a running kernel or in an
233 on-disk kernel. This information can be extracted from the kernel
234 image file with the script scripts/extract-ikconfig and used as
235 input to rebuild the current kernel or to build another kernel.
236 It can also be extracted from a running kernel by reading
237 /proc/config.gz if enabled (below).
239 config IKCONFIG_PROC
240 bool "Enable access to .config through /proc/config.gz"
241 depends on IKCONFIG && PROC_FS
242 ---help---
243 This option enables access to the kernel configuration file
244 through /proc/config.gz.
246 config CPUSETS
247 bool "Cpuset support"
248 depends on SMP
249 help
250 This option will let you create and manage CPUSETs which
251 allow dynamically partitioning a system into sets of CPUs and
252 Memory Nodes and assigning tasks to run only within those sets.
253 This is primarily useful on large SMP or NUMA systems.
255 Say N if unsure.
257 source "usr/Kconfig"
259 menuconfig EMBEDDED
260 bool "Configure standard kernel features (for small systems)"
261 help
262 This option allows certain base kernel options and settings
263 to be disabled or tweaked. This is for specialized
264 environments which can tolerate a "non-standard" kernel.
265 Only use this if you really know what you are doing.
267 config KALLSYMS
268 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
269 default y
270 help
271 Say Y here to let the kernel print out symbolic crash information and
272 symbolic stack backtraces. This increases the size of the kernel
273 somewhat, as all symbols have to be loaded into the kernel image.
275 config KALLSYMS_ALL
276 bool "Include all symbols in kallsyms"
277 depends on DEBUG_KERNEL && KALLSYMS
278 help
279 Normally kallsyms only contains the symbols of functions, for nicer
280 OOPS messages. Some debuggers can use kallsyms for other
281 symbols too: say Y here to include all symbols, if you need them
282 and you don't care about adding 300k to the size of your kernel.
284 Say N.
286 config KALLSYMS_EXTRA_PASS
287 bool "Do an extra kallsyms pass"
288 depends on KALLSYMS
289 help
290 If kallsyms is not working correctly, the build will fail with
291 inconsistent kallsyms data. If that occurs, log a bug report and
292 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
293 Always say N here unless you find a bug in kallsyms, which must be
294 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
295 you wait for kallsyms to be fixed.
298 config PRINTK
299 default y
300 bool "Enable support for printk" if EMBEDDED
301 help
302 This option enables normal printk support. Removing it
303 eliminates most of the message strings from the kernel image
304 and makes the kernel more or less silent. As this makes it
305 very difficult to diagnose system problems, saying N here is
306 strongly discouraged.
308 config BUG
309 bool "BUG() support" if EMBEDDED
310 default y
311 help
312 Disabling this option eliminates support for BUG and WARN, reducing
313 the size of your kernel image and potentially quietly ignoring
314 numerous fatal conditions. You should only consider disabling this
315 option for embedded systems with no facilities for reporting errors.
316 Just say Y.
318 config BASE_FULL
319 default y
320 bool "Enable full-sized data structures for core" if EMBEDDED
321 help
322 Disabling this option reduces the size of miscellaneous core
323 kernel data structures. This saves memory on small machines,
324 but may reduce performance.
326 config FUTEX
327 bool "Enable futex support" if EMBEDDED
328 default y
329 help
330 Disabling this option will cause the kernel to be built without
331 support for "fast userspace mutexes". The resulting kernel may not
332 run glibc-based applications correctly.
334 config EPOLL
335 bool "Enable eventpoll support" if EMBEDDED
336 default y
337 help
338 Disabling this option will cause the kernel to be built without
339 support for epoll family of system calls.
341 config CC_OPTIMIZE_FOR_SIZE
342 bool "Optimize for size" if EMBEDDED
343 default y if ARM || H8300
344 help
345 Enabling this option will pass "-Os" instead of "-O2" to gcc
346 resulting in a smaller kernel.
348 WARNING: some versions of gcc may generate incorrect code with this
349 option. If problems are observed, a gcc upgrade may be needed.
351 If unsure, say N.
353 config SHMEM
354 bool "Use full shmem filesystem" if EMBEDDED
355 default y
356 depends on MMU
357 help
358 The shmem is an internal filesystem used to manage shared memory.
359 It is backed by swap and manages resource limits. It is also exported
360 to userspace as tmpfs if TMPFS is enabled. Disabling this
361 option replaces shmem and tmpfs with the much simpler ramfs code,
362 which may be appropriate on small systems without swap.
364 config CC_ALIGN_FUNCTIONS
365 int "Function alignment" if EMBEDDED
366 default 0
367 help
368 Align the start of functions to the next power-of-two greater than n,
369 skipping up to n bytes. For instance, 32 aligns functions
370 to the next 32-byte boundary, but 24 would align to the next
371 32-byte boundary only if this can be done by skipping 23 bytes or less.
372 Zero means use compiler's default.
374 config CC_ALIGN_LABELS
375 int "Label alignment" if EMBEDDED
376 default 0
377 help
378 Align all branch targets to a power-of-two boundary, skipping
379 up to n bytes like ALIGN_FUNCTIONS. This option can easily
380 make code slower, because it must insert dummy operations for
381 when the branch target is reached in the usual flow of the code.
382 Zero means use compiler's default.
384 config CC_ALIGN_LOOPS
385 int "Loop alignment" if EMBEDDED
386 default 0
387 help
388 Align loops to a power-of-two boundary, skipping up to n bytes.
389 Zero means use compiler's default.
391 config CC_ALIGN_JUMPS
392 int "Jump alignment" if EMBEDDED
393 default 0
394 help
395 Align branch targets to a power-of-two boundary, for branch
396 targets where the targets can only be reached by jumping,
397 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
398 no dummy operations need be executed.
399 Zero means use compiler's default.
401 endmenu # General setup
403 config TINY_SHMEM
404 default !SHMEM
405 bool
407 config BASE_SMALL
408 int
409 default 0 if BASE_FULL
410 default 1 if !BASE_FULL
412 menu "Loadable module support"
414 config MODULES
415 bool "Enable loadable module support"
416 help
417 Kernel modules are small pieces of compiled code which can
418 be inserted in the running kernel, rather than being
419 permanently built into the kernel. You use the "modprobe"
420 tool to add (and sometimes remove) them. If you say Y here,
421 many parts of the kernel can be built as modules (by
422 answering M instead of Y where indicated): this is most
423 useful for infrequently used options which are not required
424 for booting. For more information, see the man pages for
425 modprobe, lsmod, modinfo, insmod and rmmod.
427 If you say Y here, you will need to run "make
428 modules_install" to put the modules under /lib/modules/
429 where modprobe can find them (you may need to be root to do
430 this).
432 If unsure, say Y.
434 config MODULE_UNLOAD
435 bool "Module unloading"
436 depends on MODULES
437 help
438 Without this option you will not be able to unload any
439 modules (note that some modules may not be unloadable
440 anyway), which makes your kernel slightly smaller and
441 simpler. If unsure, say Y.
443 config MODULE_FORCE_UNLOAD
444 bool "Forced module unloading"
445 depends on MODULE_UNLOAD && EXPERIMENTAL
446 help
447 This option allows you to force a module to unload, even if the
448 kernel believes it is unsafe: the kernel will remove the module
449 without waiting for anyone to stop using it (using the -f option to
450 rmmod). This is mainly for kernel developers and desperate users.
451 If unsure, say N.
453 config OBSOLETE_MODPARM
454 bool
455 default y
456 depends on MODULES
457 help
458 You need this option to use module parameters on modules which
459 have not been converted to the new module parameter system yet.
460 If unsure, say Y.
462 config MODVERSIONS
463 bool "Module versioning support (EXPERIMENTAL)"
464 depends on MODULES && EXPERIMENTAL
465 help
466 Usually, you have to use modules compiled with your kernel.
467 Saying Y here makes it sometimes possible to use modules
468 compiled for different kernels, by adding enough information
469 to the modules to (hopefully) spot any changes which would
470 make them incompatible with the kernel you are running. If
471 unsure, say N.
473 config MODULE_SRCVERSION_ALL
474 bool "Source checksum for all modules"
475 depends on MODULES
476 help
477 Modules which contain a MODULE_VERSION get an extra "srcversion"
478 field inserted into their modinfo section, which contains a
479 sum of the source files which made it. This helps maintainers
480 see exactly which source was used to build a module (since
481 others sometimes change the module source without updating
482 the version). With this option, such a "srcversion" field
483 will be created for all modules. If unsure, say N.
485 config KMOD
486 bool "Automatic kernel module loading"
487 depends on MODULES
488 help
489 Normally when you have selected some parts of the kernel to
490 be created as kernel modules, you must load them (using the
491 "modprobe" command) before you can use them. If you say Y
492 here, some parts of the kernel will be able to load modules
493 automatically: when a part of the kernel needs a module, it
494 runs modprobe with the appropriate arguments, thereby
495 loading the module if it is available. If unsure, say Y.
497 config STOP_MACHINE
498 bool
499 default y
500 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
501 help
502 Need stop_machine() primitive.
503 endmenu