2 menu "Code maturity level options"
5 bool "Prompt for development and/or incomplete code/drivers"
7 Some of the various things that Linux supports (such as network
8 drivers, file systems, network protocols, etc.) can be in a state
9 of development where the functionality, stability, or the level of
10 testing is not yet high enough for general use. This is usually
11 known as the "alpha-test" phase among developers. If a feature is
12 currently in alpha-test, then the developers usually discourage
13 uninformed widespread use of this feature by the general public to
14 avoid "Why doesn't this work?" type mail messages. However, active
15 testing and use of these systems is welcomed. Just be aware that it
16 may not meet the normal level of reliability or it may fail to work
17 in some special cases. Detailed bug reports from people familiar
18 with the kernel internals are usually welcomed by the developers
19 (before submitting bug reports, please read the documents
20 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
21 <file:Documentation/BUG-HUNTING>, and
22 <file:Documentation/oops-tracing.txt> in the kernel source).
24 This option will also make obsoleted drivers available. These are
25 drivers that have been replaced by something else, and/or are
26 scheduled to be removed in a future kernel release.
28 Unless you intend to help test and develop a feature or driver that
29 falls into this category, or you have a situation that requires
30 using these features, you should probably say N here, which will
31 cause the configurator to present you with fewer choices. If
32 you say Y here, you will be offered the choice of using features or
33 drivers that are currently considered to be in the alpha-test phase.
36 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
39 Select this option if you don't even want to see the option
40 to configure known-broken drivers.
45 bool "Select only drivers that don't need compile-time external firmware" if EXPERIMENTAL
48 Select this option if you don't have magic firmware for drivers that
55 depends on !CLEAN_COMPILE
60 depends on BROKEN || !SMP
69 bool "Support for paging of anonymous memory (swap)"
73 This option allows you to choose whether you want to have support
74 for socalled swap devices or swap files in your kernel that are
75 used to provide more virtual memory than the actual RAM present
76 in your computer. If unsure say Y.
82 Inter Process Communication is a suite of library functions and
83 system calls which let processes (running programs) synchronize and
84 exchange information. It is generally considered to be a good thing,
85 and some programs won't run unless you say Y here. In particular, if
86 you want to run the DOS emulator dosemu under Linux (read the
87 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
88 you'll need to say Y here.
90 You can find documentation about IPC with "info ipc" and also in
91 section 6.4 of the Linux Programmer's Guide, available from
92 <http://www.tldp.org/guides.html>.
95 bool "POSIX Message Queues"
96 depends on NET && EXPERIMENTAL
98 POSIX variant of message queues is a part of IPC. In POSIX message
99 queues every message has a priority which decides about succession
100 of receiving it by a process. If you want to compile and run
101 programs written e.g. for Solaris with use of its POSIX message
102 queues (functions mq_*) say Y here. To use this feature you will
103 also need mqueue library, available from
104 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
106 POSIX message queues are visible as a filesystem called 'mqueue'
107 and can be mounted somewhere if you want to do filesystem
108 operations on message queues.
112 config BSD_PROCESS_ACCT
113 bool "BSD Process Accounting"
115 If you say Y here, a user level program will be able to instruct the
116 kernel (via a special system call) to write process accounting
117 information to a file: whenever a process exits, information about
118 that process will be appended to the file by the kernel. The
119 information includes things such as creation time, owning user,
120 command name, memory usage, controlling terminal etc. (the complete
121 list is in the struct acct in <file:include/linux/acct.h>). It is
122 up to the user level program to do useful things with this
123 information. This is generally a good idea, so say Y.
125 config BSD_PROCESS_ACCT_V3
126 bool "BSD Process Accounting version 3 file format"
127 depends on BSD_PROCESS_ACCT
130 If you say Y here, the process accounting information is written
131 in a new file format that also logs the process IDs of each
132 process and it's parent. Note that this file format is incompatible
133 with previous v0/v1/v2 file formats, so you will need updated tools
134 for processing it. A preliminary version of these tools is available
135 at <http://http://www.de.kernel.org/pub/linux/utils/acct/>.
138 bool "Sysctl support"
140 The sysctl interface provides a means of dynamically changing
141 certain kernel parameters and variables on the fly without requiring
142 a recompile of the kernel or reboot of the system. The primary
143 interface consists of a system call, but if you say Y to "/proc
144 file system support", a tree of modifiable sysctl entries will be
145 generated beneath the /proc/sys directory. They are explained in the
146 files in <file:Documentation/sysctl/>. Note that enabling this
147 option will enlarge the kernel by at least 8 KB.
149 As it is generally a good thing, you should say Y here unless
150 building a kernel for install/rescue disks or your system is very
154 bool "Auditing support"
155 default y if SECURITY_SELINUX
158 Enable auditing infrastructure that can be used with another
159 kernel subsystem, such as SELinux (which requires this for
160 logging of avc messages output). Does not do system-call
161 auditing without CONFIG_AUDITSYSCALL.
164 bool "Enable system-call auditing support"
165 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
166 default y if SECURITY_SELINUX
169 Enable low-overhead system-call auditing infrastructure that
170 can be used independently or with another kernel subsystem,
174 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
176 default 17 if ARCH_S390
177 default 16 if X86_NUMAQ || IA64
181 Select kernel log buffer size as a power of 2.
182 Defaults and Examples:
183 17 => 128 KB for S/390
184 16 => 64 KB for x86 NUMAQ or IA-64
186 14 => 16 KB for uniprocessor
191 bool "Support for hot-pluggable devices" if !ARCH_S390
194 Say Y here if you want to plug devices into your computer while
195 the system is running, and be able to use them quickly. In many
196 cases, the devices can likewise be unplugged at any time too.
198 One well known example of this is PCMCIA- or PC-cards, credit-card
199 size devices such as network cards, modems or hard drives which are
200 plugged into slots found on all modern laptop computers. Another
201 example, used on modern desktops as well as laptops, is USB.
203 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
204 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
205 Then your kernel will automatically call out to a user mode "policy
206 agent" (/sbin/hotplug) to load modules and set up software needed
207 to use devices as you hotplug them.
210 bool "Kernel .config support"
212 This option enables the complete Linux kernel ".config" file
213 contents to be saved in the kernel. It provides documentation
214 of which kernel options are used in a running kernel or in an
215 on-disk kernel. This information can be extracted from the kernel
216 image file with the script scripts/extract-ikconfig and used as
217 input to rebuild the current kernel or to build another kernel.
218 It can also be extracted from a running kernel by reading
219 /proc/config.gz if enabled (below).
222 bool "Enable access to .config through /proc/config.gz"
223 depends on IKCONFIG && PROC_FS
225 This option enables access to the kernel configuration file
226 through /proc/config.gz.
230 bool "Configure standard kernel features (for small systems)"
232 This option allows certain base kernel options and settings
233 to be disabled or tweaked. This is for specialized
234 environments which can tolerate a "non-standard" kernel.
235 Only use this if you really know what you are doing.
238 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
241 Say Y here to let the kernel print out symbolic crash information and
242 symbolic stack backtraces. This increases the size of the kernel
243 somewhat, as all symbols have to be loaded into the kernel image.
246 bool "Include all symbols in kallsyms"
247 depends on DEBUG_KERNEL && KALLSYMS
249 Normally kallsyms only contains the symbols of functions, for nicer
250 OOPS messages. Some debuggers can use kallsyms for other
251 symbols too: say Y here to include all symbols, and you
252 don't care about adding 300k to the size of your kernel.
256 config KALLSYMS_EXTRA_PASS
257 bool "Do an extra kallsyms pass"
260 If kallsyms is not working correctly, the build will fail with
261 inconsistent kallsyms data. If that occurs, log a bug report and
262 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
263 Always say N here unless you find a bug in kallsyms, which must be
264 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
265 you wait for kallsyms to be fixed.
268 bool "Enable futex support" if EMBEDDED
271 Disabling this option will cause the kernel to be built without
272 support for "fast userspace mutexes". The resulting kernel may not
273 run glibc-based applications correctly.
276 bool "Enable eventpoll support" if EMBEDDED
279 Disabling this option will cause the kernel to be built without
280 support for epoll family of system calls.
282 source "drivers/block/Kconfig.iosched"
284 config CC_OPTIMIZE_FOR_SIZE
285 bool "Optimize for size" if EMBEDDED
286 default y if ARM || H8300
289 Enabling this option will pass "-Os" instead of "-O2" to gcc
290 resulting in a smaller kernel.
292 WARNING: some versions of gcc may generate incorrect code with this
293 option. If problems are observed, a gcc upgrade may be needed.
297 endmenu # General setup
300 menu "Loadable module support"
303 bool "Enable loadable module support"
305 Kernel modules are small pieces of compiled code which can
306 be inserted in the running kernel, rather than being
307 permanently built into the kernel. You use the "modprobe"
308 tool to add (and sometimes remove) them. If you say Y here,
309 many parts of the kernel can be built as modules (by
310 answering M instead of Y where indicated): this is most
311 useful for infrequently used options which are not required
312 for booting. For more information, see the man pages for
313 modprobe, lsmod, modinfo, insmod and rmmod.
315 If you say Y here, you will need to run "make
316 modules_install" to put the modules under /lib/modules/
317 where modprobe can find them (you may need to be root to do
323 bool "Module unloading"
326 Without this option you will not be able to unload any
327 modules (note that some modules may not be unloadable
328 anyway), which makes your kernel slightly smaller and
329 simpler. If unsure, say Y.
331 config MODULE_FORCE_UNLOAD
332 bool "Forced module unloading"
333 depends on MODULE_UNLOAD && EXPERIMENTAL
335 This option allows you to force a module to unload, even if the
336 kernel believes it is unsafe: the kernel will remove the module
337 without waiting for anyone to stop using it (using the -f option to
338 rmmod). This is mainly for kernel developers and desperate users.
341 config OBSOLETE_MODPARM
346 You need this option to use module parameters on modules which
347 have not been converted to the new module parameter system yet.
351 bool "Module versioning support (EXPERIMENTAL)"
352 depends on MODULES && EXPERIMENTAL
354 Usually, you have to use modules compiled with your kernel.
355 Saying Y here makes it sometimes possible to use modules
356 compiled for different kernels, by adding enough information
357 to the modules to (hopefully) spot any changes which would
358 make them incompatible with the kernel you are running. If
362 bool "Automatic kernel module loading"
365 Normally when you have selected some parts of the kernel to
366 be created as kernel modules, you must load them (using the
367 "modprobe" command) before you can use them. If you say Y
368 here, some parts of the kernel will be able to load modules
369 automatically: when a part of the kernel needs a module, it
370 runs modprobe with the appropriate arguments, thereby
371 loading the module if it is available. If unsure, say Y.
376 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
378 Need stop_machine() primitive.