| blob | 05a75c4f5ce2a230f9193233dd4e05737878b5bf |
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24 drivers that have been replaced by something else, and/or are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 This is the value of the two limits on the number of argument and of
64 env.var 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 SWAP
81 bool "Support for paging of anonymous memory (swap)"
82 depends on MMU
83 default y
84 help
85 This option allows you to choose whether you want to have support
86 for socalled swap devices or swap files in your kernel that are
87 used to provide more virtual memory than the actual RAM present
88 in your computer. If unsure say Y.
90 config SYSVIPC
91 bool "System V IPC"
92 depends on MMU
93 ---help---
94 Inter Process Communication is a suite of library functions and
95 system calls which let processes (running programs) synchronize and
96 exchange information. It is generally considered to be a good thing,
97 and some programs won't run unless you say Y here. In particular, if
98 you want to run the DOS emulator dosemu under Linux (read the
99 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
100 you'll need to say Y here.
102 You can find documentation about IPC with "info ipc" and also in
103 section 6.4 of the Linux Programmer's Guide, available from
104 <http://www.tldp.org/guides.html>.
106 config POSIX_MQUEUE
107 bool "POSIX Message Queues"
108 depends on NET && EXPERIMENTAL
109 ---help---
110 POSIX variant of message queues is a part of IPC. In POSIX message
111 queues every message has a priority which decides about succession
112 of receiving it by a process. If you want to compile and run
113 programs written e.g. for Solaris with use of its POSIX message
114 queues (functions mq_*) say Y here. To use this feature you will
115 also need mqueue library, available from
116 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
118 POSIX message queues are visible as a filesystem called 'mqueue'
119 and can be mounted somewhere if you want to do filesystem
120 operations on message queues.
122 If unsure, say Y.
124 config BSD_PROCESS_ACCT
125 bool "BSD Process Accounting"
126 help
127 If you say Y here, a user level program will be able to instruct the
128 kernel (via a special system call) to write process accounting
129 information to a file: whenever a process exits, information about
130 that process will be appended to the file by the kernel. The
131 information includes things such as creation time, owning user,
132 command name, memory usage, controlling terminal etc. (the complete
133 list is in the struct acct in <file:include/linux/acct.h>). It is
134 up to the user level program to do useful things with this
135 information. This is generally a good idea, so say Y.
137 config BSD_PROCESS_ACCT_V3
138 bool "BSD Process Accounting version 3 file format"
139 depends on BSD_PROCESS_ACCT
140 default n
141 help
142 If you say Y here, the process accounting information is written
143 in a new file format that also logs the process IDs of each
144 process and it's parent. Note that this file format is incompatible
145 with previous v0/v1/v2 file formats, so you will need updated tools
146 for processing it. A preliminary version of these tools is available
147 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
149 config SYSCTL
150 bool "Sysctl support"
151 ---help---
152 The sysctl interface provides a means of dynamically changing
153 certain kernel parameters and variables on the fly without requiring
154 a recompile of the kernel or reboot of the system. The primary
155 interface consists of a system call, but if you say Y to "/proc
156 file system support", a tree of modifiable sysctl entries will be
157 generated beneath the /proc/sys directory. They are explained in the
158 files in <file:Documentation/sysctl/>. Note that enabling this
159 option will enlarge the kernel by at least 8 KB.
161 As it is generally a good thing, you should say Y here unless
162 building a kernel for install/rescue disks or your system is very
163 limited in memory.
165 config AUDIT
166 bool "Auditing support"
167 depends on NET
168 default y if SECURITY_SELINUX
169 help
170 Enable auditing infrastructure that can be used with another
171 kernel subsystem, such as SELinux (which requires this for
172 logging of avc messages output). Does not do system-call
173 auditing without CONFIG_AUDITSYSCALL.
175 config AUDITSYSCALL
176 bool "Enable system-call auditing support"
177 depends on AUDIT && (X86 || PPC || PPC64 || ARCH_S390 || IA64 || UML || SPARC64)
178 default y if SECURITY_SELINUX
179 help
180 Enable low-overhead system-call auditing infrastructure that
181 can be used independently or with another kernel subsystem,
182 such as SELinux.
184 config HOTPLUG
185 bool "Support for hot-pluggable devices" if !ARCH_S390
186 default ARCH_S390
187 help
188 This option is provided for the case where no in-kernel-tree
189 modules require HOTPLUG functionality, but a module built
190 outside the kernel tree does. Such modules require Y here.
192 config KOBJECT_UEVENT
193 bool "Kernel Userspace Events"
194 depends on NET
195 default y
196 help
197 This option enables the kernel userspace event layer, which is a
198 simple mechanism for kernel-to-user communication over a netlink
199 socket.
200 The goal of the kernel userspace events layer is to provide a simple
201 and efficient events system, that notifies userspace about kobject
202 state changes. This will enable applications to just listen for
203 events instead of polling system devices and files.
204 Hotplug events (kobject addition and removal) are also available on
205 the netlink socket in addition to the execution of /sbin/hotplug if
206 CONFIG_HOTPLUG is enabled.
208 Say Y, unless you are building a system requiring minimal memory
209 consumption.
211 config IKCONFIG
212 bool "Kernel .config support"
213 ---help---
214 This option enables the complete Linux kernel ".config" file
215 contents to be saved in the kernel. It provides documentation
216 of which kernel options are used in a running kernel or in an
217 on-disk kernel. This information can be extracted from the kernel
218 image file with the script scripts/extract-ikconfig and used as
219 input to rebuild the current kernel or to build another kernel.
220 It can also be extracted from a running kernel by reading
221 /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.
230 config CPUSETS
231 bool "Cpuset support"
232 depends on SMP
233 help
234 This option will let you create and manage CPUSETs which
235 allow dynamically partitioning a system into sets of CPUs and
236 Memory Nodes and assigning tasks to run only within those sets.
237 This is primarily useful on large SMP or NUMA systems.
239 Say N if unsure.
241 menuconfig EMBEDDED
242 bool "Configure standard kernel features (for small systems)"
243 help
244 This option allows certain base kernel options and settings
245 to be disabled or tweaked. This is for specialized
246 environments which can tolerate a "non-standard" kernel.
247 Only use this if you really know what you are doing.
249 config KALLSYMS
250 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
251 default y
252 help
253 Say Y here to let the kernel print out symbolic crash information and
254 symbolic stack backtraces. This increases the size of the kernel
255 somewhat, as all symbols have to be loaded into the kernel image.
257 config KALLSYMS_ALL
258 bool "Include all symbols in kallsyms"
259 depends on DEBUG_KERNEL && KALLSYMS
260 help
261 Normally kallsyms only contains the symbols of functions, for nicer
262 OOPS messages. Some debuggers can use kallsyms for other
263 symbols too: say Y here to include all symbols, and you
264 don't care about adding 300k to the size of your kernel.
266 Say N.
268 config KALLSYMS_EXTRA_PASS
269 bool "Do an extra kallsyms pass"
270 depends on KALLSYMS
271 help
272 If kallsyms is not working correctly, the build will fail with
273 inconsistent kallsyms data. If that occurs, log a bug report and
274 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
275 Always say N here unless you find a bug in kallsyms, which must be
276 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
277 you wait for kallsyms to be fixed.
280 config PRINTK
281 default y
282 bool "Enable support for printk" if EMBEDDED
283 help
284 This option enables normal printk support. Removing it
285 eliminates most of the message strings from the kernel image
286 and makes the kernel more or less silent. As this makes it
287 very difficult to diagnose system problems, saying N here is
288 strongly discouraged.
290 config BUG
291 bool "BUG() support" if EMBEDDED
292 default y
293 help
294 Disabling this option eliminates support for BUG and WARN, reducing
295 the size of your kernel image and potentially quietly ignoring
296 numerous fatal conditions. You should only consider disabling this
297 option for embedded systems with no facilities for reporting errors.
298 Just say Y.
300 config BASE_FULL
301 default y
302 bool "Enable full-sized data structures for core" if EMBEDDED
303 help
304 Disabling this option reduces the size of miscellaneous core
305 kernel data structures. This saves memory on small machines,
306 but may reduce performance.
308 config FUTEX
309 bool "Enable futex support" if EMBEDDED
310 default y
311 help
312 Disabling this option will cause the kernel to be built without
313 support for "fast userspace mutexes". The resulting kernel may not
314 run glibc-based applications correctly.
316 config EPOLL
317 bool "Enable eventpoll support" if EMBEDDED
318 default y
319 help
320 Disabling this option will cause the kernel to be built without
321 support for epoll family of system calls.
323 config CC_OPTIMIZE_FOR_SIZE
324 bool "Optimize for size" if EMBEDDED
325 default y if ARM || H8300
326 help
327 Enabling this option will pass "-Os" instead of "-O2" to gcc
328 resulting in a smaller kernel.
330 WARNING: some versions of gcc may generate incorrect code with this
331 option. If problems are observed, a gcc upgrade may be needed.
333 If unsure, say N.
335 config SHMEM
336 bool "Use full shmem filesystem" if EMBEDDED
337 default y
338 depends on MMU
339 help
340 The shmem is an internal filesystem used to manage shared memory.
341 It is backed by swap and manages resource limits. It is also exported
342 to userspace as tmpfs if TMPFS is enabled. Disabling this
343 option replaces shmem and tmpfs with the much simpler ramfs code,
344 which may be appropriate on small systems without swap.
346 config CC_ALIGN_FUNCTIONS
347 int "Function alignment" if EMBEDDED
348 default 0
349 help
350 Align the start of functions to the next power-of-two greater than n,
351 skipping up to n bytes. For instance, 32 aligns functions
352 to the next 32-byte boundary, but 24 would align to the next
353 32-byte boundary only if this can be done by skipping 23 bytes or less.
354 Zero means use compiler's default.
356 config CC_ALIGN_LABELS
357 int "Label alignment" if EMBEDDED
358 default 0
359 help
360 Align all branch targets to a power-of-two boundary, skipping
361 up to n bytes like ALIGN_FUNCTIONS. This option can easily
362 make code slower, because it must insert dummy operations for
363 when the branch target is reached in the usual flow of the code.
364 Zero means use compiler's default.
366 config CC_ALIGN_LOOPS
367 int "Loop alignment" if EMBEDDED
368 default 0
369 help
370 Align loops to a power-of-two boundary, skipping up to n bytes.
371 Zero means use compiler's default.
373 config CC_ALIGN_JUMPS
374 int "Jump alignment" if EMBEDDED
375 default 0
376 help
377 Align branch targets to a power-of-two boundary, for branch
378 targets where the targets can only be reached by jumping,
379 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
380 no dummy operations need be executed.
381 Zero means use compiler's default.
383 endmenu # General setup
385 config TINY_SHMEM
386 default !SHMEM
387 bool
389 config BASE_SMALL
390 int
391 default 0 if BASE_FULL
392 default 1 if !BASE_FULL
394 menu "Loadable module support"
396 config MODULES
397 bool "Enable loadable module support"
398 help
399 Kernel modules are small pieces of compiled code which can
400 be inserted in the running kernel, rather than being
401 permanently built into the kernel. You use the "modprobe"
402 tool to add (and sometimes remove) them. If you say Y here,
403 many parts of the kernel can be built as modules (by
404 answering M instead of Y where indicated): this is most
405 useful for infrequently used options which are not required
406 for booting. For more information, see the man pages for
407 modprobe, lsmod, modinfo, insmod and rmmod.
409 If you say Y here, you will need to run "make
410 modules_install" to put the modules under /lib/modules/
411 where modprobe can find them (you may need to be root to do
412 this).
414 If unsure, say Y.
416 config MODULE_UNLOAD
417 bool "Module unloading"
418 depends on MODULES
419 help
420 Without this option you will not be able to unload any
421 modules (note that some modules may not be unloadable
422 anyway), which makes your kernel slightly smaller and
423 simpler. If unsure, say Y.
425 config MODULE_FORCE_UNLOAD
426 bool "Forced module unloading"
427 depends on MODULE_UNLOAD && EXPERIMENTAL
428 help
429 This option allows you to force a module to unload, even if the
430 kernel believes it is unsafe: the kernel will remove the module
431 without waiting for anyone to stop using it (using the -f option to
432 rmmod). This is mainly for kernel developers and desperate users.
433 If unsure, say N.
435 config OBSOLETE_MODPARM
436 bool
437 default y
438 depends on MODULES
439 help
440 You need this option to use module parameters on modules which
441 have not been converted to the new module parameter system yet.
442 If unsure, say Y.
444 config MODVERSIONS
445 bool "Module versioning support (EXPERIMENTAL)"
446 depends on MODULES && EXPERIMENTAL
447 help
448 Usually, you have to use modules compiled with your kernel.
449 Saying Y here makes it sometimes possible to use modules
450 compiled for different kernels, by adding enough information
451 to the modules to (hopefully) spot any changes which would
452 make them incompatible with the kernel you are running. If
453 unsure, say N.
455 config MODULE_SRCVERSION_ALL
456 bool "Source checksum for all modules"
457 depends on MODULES
458 help
459 Modules which contain a MODULE_VERSION get an extra "srcversion"
460 field inserted into their modinfo section, which contains a
461 sum of the source files which made it. This helps maintainers
462 see exactly which source was used to build a module (since
463 others sometimes change the module source without updating
464 the version). With this option, such a "srcversion" field
465 will be created for all modules. If unsure, say N.
467 config KMOD
468 bool "Automatic kernel module loading"
469 depends on MODULES
470 help
471 Normally when you have selected some parts of the kernel to
472 be created as kernel modules, you must load them (using the
473 "modprobe" command) before you can use them. If you say Y
474 here, some parts of the kernel will be able to load modules
475 automatically: when a part of the kernel needs a module, it
476 runs modprobe with the appropriate arguments, thereby
477 loading the module if it is available. If unsure, say Y.
479 config STOP_MACHINE
480 bool
481 default y
482 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
483 help
484 Need stop_machine() primitive.
485 endmenu