1 menu "Code maturity level options"
4 bool "Prompt for development and/or incomplete code/drivers"
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24 drivers that have been replaced by something else, and/or are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.
35 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL
38 Select this option if you don't even want to see the option
39 to configure known-broken drivers.
45 depends on !CLEAN_COMPILE
50 depends on BROKEN || !SMP
55 depends on SMP || PREEMPT
63 string "Local version - append to kernel release"
65 Append an extra string to the end of your kernel version.
66 This will show up when you type uname, for example.
67 The string you set here will be appended after the contents of
68 any files with a filename matching localversion* in your
69 object and source tree, in that order. Your total string can
70 be a maximum of 64 characters.
73 bool "Support for paging of anonymous memory (swap)"
77 This option allows you to choose whether you want to have support
78 for socalled swap devices or swap files in your kernel that are
79 used to provide more virtual memory than the actual RAM present
80 in your computer. If unsure say Y.
86 Inter Process Communication is a suite of library functions and
87 system calls which let processes (running programs) synchronize and
88 exchange information. It is generally considered to be a good thing,
89 and some programs won't run unless you say Y here. In particular, if
90 you want to run the DOS emulator dosemu under Linux (read the
91 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
92 you'll need to say Y here.
94 You can find documentation about IPC with "info ipc" and also in
95 section 6.4 of the Linux Programmer's Guide, available from
96 <http://www.tldp.org/guides.html>.
99 bool "POSIX Message Queues"
100 depends on NET && EXPERIMENTAL
102 POSIX variant of message queues is a part of IPC. In POSIX message
103 queues every message has a priority which decides about succession
104 of receiving it by a process. If you want to compile and run
105 programs written e.g. for Solaris with use of its POSIX message
106 queues (functions mq_*) say Y here. To use this feature you will
107 also need mqueue library, available from
108 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
110 POSIX message queues are visible as a filesystem called 'mqueue'
111 and can be mounted somewhere if you want to do filesystem
112 operations on message queues.
116 config BSD_PROCESS_ACCT
117 bool "BSD Process Accounting"
119 If you say Y here, a user level program will be able to instruct the
120 kernel (via a special system call) to write process accounting
121 information to a file: whenever a process exits, information about
122 that process will be appended to the file by the kernel. The
123 information includes things such as creation time, owning user,
124 command name, memory usage, controlling terminal etc. (the complete
125 list is in the struct acct in <file:include/linux/acct.h>). It is
126 up to the user level program to do useful things with this
127 information. This is generally a good idea, so say Y.
129 config BSD_PROCESS_ACCT_V3
130 bool "BSD Process Accounting version 3 file format"
131 depends on BSD_PROCESS_ACCT
134 If you say Y here, the process accounting information is written
135 in a new file format that also logs the process IDs of each
136 process and it's parent. Note that this file format is incompatible
137 with previous v0/v1/v2 file formats, so you will need updated tools
138 for processing it. A preliminary version of these tools is available
139 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
142 bool "Sysctl support"
144 The sysctl interface provides a means of dynamically changing
145 certain kernel parameters and variables on the fly without requiring
146 a recompile of the kernel or reboot of the system. The primary
147 interface consists of a system call, but if you say Y to "/proc
148 file system support", a tree of modifiable sysctl entries will be
149 generated beneath the /proc/sys directory. They are explained in the
150 files in <file:Documentation/sysctl/>. Note that enabling this
151 option will enlarge the kernel by at least 8 KB.
153 As it is generally a good thing, you should say Y here unless
154 building a kernel for install/rescue disks or your system is very
158 bool "Auditing support"
159 default y if SECURITY_SELINUX
162 Enable auditing infrastructure that can be used with another
163 kernel subsystem, such as SELinux (which requires this for
164 logging of avc messages output). Does not do system-call
165 auditing without CONFIG_AUDITSYSCALL.
168 bool "Enable system-call auditing support"
169 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64)
170 default y if SECURITY_SELINUX
173 Enable low-overhead system-call auditing infrastructure that
174 can be used independently or with another kernel subsystem,
178 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
180 default 17 if ARCH_S390
181 default 16 if X86_NUMAQ || IA64
185 Select kernel log buffer size as a power of 2.
186 Defaults and Examples:
187 17 => 128 KB for S/390
188 16 => 64 KB for x86 NUMAQ or IA-64
190 14 => 16 KB for uniprocessor
195 bool "Support for hot-pluggable devices" if !ARCH_S390
198 Say Y here if you want to plug devices into your computer while
199 the system is running, and be able to use them quickly. In many
200 cases, the devices can likewise be unplugged at any time too.
202 One well known example of this is PCMCIA- or PC-cards, credit-card
203 size devices such as network cards, modems or hard drives which are
204 plugged into slots found on all modern laptop computers. Another
205 example, used on modern desktops as well as laptops, is USB.
207 Enable HOTPLUG and KMOD, and build a modular kernel. Get agent
208 software (at <http://linux-hotplug.sourceforge.net/>) and install it.
209 Then your kernel will automatically call out to a user mode "policy
210 agent" (/sbin/hotplug) to load modules and set up software needed
211 to use devices as you hotplug them.
213 config KOBJECT_UEVENT
214 bool "Kernel Userspace Events"
218 This option enables the kernel userspace event layer, which is a
219 simple mechanism for kernel-to-user communication over a netlink
221 The goal of the kernel userspace events layer is to provide a simple
222 and efficient events system, that notifies userspace about kobject
223 state changes. This will enable applications to just listen for
224 events instead of polling system devices and files.
225 Hotplug events (kobject addition and removal) are also available on
226 the netlink socket in addition to the execution of /sbin/hotplug if
227 CONFIG_HOTPLUG is enabled.
229 Say Y, unless you are building a system requiring minimal memory
233 bool "Kernel .config support"
235 This option enables the complete Linux kernel ".config" file
236 contents to be saved in the kernel. It provides documentation
237 of which kernel options are used in a running kernel or in an
238 on-disk kernel. This information can be extracted from the kernel
239 image file with the script scripts/extract-ikconfig and used as
240 input to rebuild the current kernel or to build another kernel.
241 It can also be extracted from a running kernel by reading
242 /proc/config.gz if enabled (below).
245 bool "Enable access to .config through /proc/config.gz"
246 depends on IKCONFIG && PROC_FS
248 This option enables access to the kernel configuration file
249 through /proc/config.gz.
253 bool "Configure standard kernel features (for small systems)"
255 This option allows certain base kernel options and settings
256 to be disabled or tweaked. This is for specialized
257 environments which can tolerate a "non-standard" kernel.
258 Only use this if you really know what you are doing.
261 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
264 Say Y here to let the kernel print out symbolic crash information and
265 symbolic stack backtraces. This increases the size of the kernel
266 somewhat, as all symbols have to be loaded into the kernel image.
269 bool "Include all symbols in kallsyms"
270 depends on DEBUG_KERNEL && KALLSYMS
272 Normally kallsyms only contains the symbols of functions, for nicer
273 OOPS messages. Some debuggers can use kallsyms for other
274 symbols too: say Y here to include all symbols, and you
275 don't care about adding 300k to the size of your kernel.
279 config KALLSYMS_EXTRA_PASS
280 bool "Do an extra kallsyms pass"
283 If kallsyms is not working correctly, the build will fail with
284 inconsistent kallsyms data. If that occurs, log a bug report and
285 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
286 Always say N here unless you find a bug in kallsyms, which must be
287 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
288 you wait for kallsyms to be fixed.
291 bool "Enable futex support" if EMBEDDED
294 Disabling this option will cause the kernel to be built without
295 support for "fast userspace mutexes". The resulting kernel may not
296 run glibc-based applications correctly.
299 bool "Enable eventpoll support" if EMBEDDED
302 Disabling this option will cause the kernel to be built without
303 support for epoll family of system calls.
305 config CC_OPTIMIZE_FOR_SIZE
306 bool "Optimize for size" if EMBEDDED
307 default y if ARM || H8300
310 Enabling this option will pass "-Os" instead of "-O2" to gcc
311 resulting in a smaller kernel.
313 WARNING: some versions of gcc may generate incorrect code with this
314 option. If problems are observed, a gcc upgrade may be needed.
320 bool "Use full shmem filesystem" if EMBEDDED && MMU
322 The shmem is an internal filesystem used to manage shared memory.
323 It is backed by swap and manages resource limits. It is also exported
324 to userspace as tmpfs if TMPFS is enabled. Disabling this
325 option replaces shmem and tmpfs with the much simpler ramfs code,
326 which may be appropriate on small systems without swap.
328 config CC_ALIGN_FUNCTIONS
329 int "Function alignment" if EMBEDDED
332 Align the start of functions to the next power-of-two greater than n,
333 skipping up to n bytes. For instance, 32 aligns functions
334 to the next 32-byte boundary, but 24 would align to the next
335 32-byte boundary only if this can be done by skipping 23 bytes or less.
336 Zero means use compiler's default.
338 config CC_ALIGN_LABELS
339 int "Label alignment" if EMBEDDED
342 Align all branch targets to a power-of-two boundary, skipping
343 up to n bytes like ALIGN_FUNCTIONS. This option can easily
344 make code slower, because it must insert dummy operations for
345 when the branch target is reached in the usual flow of the code.
346 Zero means use compiler's default.
348 config CC_ALIGN_LOOPS
349 int "Loop alignment" if EMBEDDED
352 Align loops to a power-of-two boundary, skipping up to n bytes.
353 Zero means use compiler's default.
355 config CC_ALIGN_JUMPS
356 int "Jump alignment" if EMBEDDED
359 Align branch targets to a power-of-two boundary, for branch
360 targets where the targets can only be reached by jumping,
361 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
362 no dummy operations need be executed.
363 Zero means use compiler's default.
365 endmenu # General setup
371 menu "Loadable module support"
374 bool "Enable loadable module support"
376 Kernel modules are small pieces of compiled code which can
377 be inserted in the running kernel, rather than being
378 permanently built into the kernel. You use the "modprobe"
379 tool to add (and sometimes remove) them. If you say Y here,
380 many parts of the kernel can be built as modules (by
381 answering M instead of Y where indicated): this is most
382 useful for infrequently used options which are not required
383 for booting. For more information, see the man pages for
384 modprobe, lsmod, modinfo, insmod and rmmod.
386 If you say Y here, you will need to run "make
387 modules_install" to put the modules under /lib/modules/
388 where modprobe can find them (you may need to be root to do
394 bool "Module unloading"
397 Without this option you will not be able to unload any
398 modules (note that some modules may not be unloadable
399 anyway), which makes your kernel slightly smaller and
400 simpler. If unsure, say Y.
402 config MODULE_FORCE_UNLOAD
403 bool "Forced module unloading"
404 depends on MODULE_UNLOAD && EXPERIMENTAL
406 This option allows you to force a module to unload, even if the
407 kernel believes it is unsafe: the kernel will remove the module
408 without waiting for anyone to stop using it (using the -f option to
409 rmmod). This is mainly for kernel developers and desperate users.
412 config OBSOLETE_MODPARM
417 You need this option to use module parameters on modules which
418 have not been converted to the new module parameter system yet.
422 bool "Module versioning support (EXPERIMENTAL)"
423 depends on MODULES && EXPERIMENTAL
425 Usually, you have to use modules compiled with your kernel.
426 Saying Y here makes it sometimes possible to use modules
427 compiled for different kernels, by adding enough information
428 to the modules to (hopefully) spot any changes which would
429 make them incompatible with the kernel you are running. If
432 config MODULE_SRCVERSION_ALL
433 bool "Source checksum for all modules"
436 Modules which contain a MODULE_VERSION get an extra "srcversion"
437 field inserted into their modinfo section, which contains a
438 sum of the source files which made it. This helps maintainers
439 see exactly which source was used to build a module (since
440 others sometimes change the module source without updating
441 the version). With this option, such a "srcversion" field
442 will be created for all modules. If unsure, say N.
445 bool "Automatic kernel module loading"
448 Normally when you have selected some parts of the kernel to
449 be created as kernel modules, you must load them (using the
450 "modprobe" command) before you can use them. If you say Y
451 here, some parts of the kernel will be able to load modules
452 automatically: when a part of the kernel needs a module, it
453 runs modprobe with the appropriate arguments, thereby
454 loading the module if it is available. If unsure, say Y.
459 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
461 Need stop_machine() primitive.