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24 drivers that have been replaced by something else, and/or are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
58 config INIT_ENV_ARG_LIMIT
60 default 32 if !USERMODE
61 default 128 if USERMODE
63 Maximum of each of the number of arguments and environment
64 variables passed to init from the kernel command line.
71 string "Local version - append to kernel release"
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"
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.
97 bool "Support for paging of anonymous memory (swap)"
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.
109 Inter Process Communication is a suite of library functions and
110 system calls which let processes (running programs) synchronize and
111 exchange information. It is generally considered to be a good thing,
112 and some programs won't run unless you say Y here. In particular, if
113 you want to run the DOS emulator dosemu under Linux (read the
114 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
115 you'll need to say Y here.
117 You can find documentation about IPC with "info ipc" and also in
118 section 6.4 of the Linux Programmer's Guide, available from
119 <http://www.tldp.org/guides.html>.
122 bool "POSIX Message Queues"
123 depends on NET && EXPERIMENTAL
125 POSIX variant of message queues is a part of IPC. In POSIX message
126 queues every message has a priority which decides about succession
127 of receiving it by a process. If you want to compile and run
128 programs written e.g. for Solaris with use of its POSIX message
129 queues (functions mq_*) say Y here. To use this feature you will
130 also need mqueue library, available from
131 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
133 POSIX message queues are visible as a filesystem called 'mqueue'
134 and can be mounted somewhere if you want to do filesystem
135 operations on message queues.
139 config BSD_PROCESS_ACCT
140 bool "BSD Process Accounting"
142 If you say Y here, a user level program will be able to instruct the
143 kernel (via a special system call) to write process accounting
144 information to a file: whenever a process exits, information about
145 that process will be appended to the file by the kernel. The
146 information includes things such as creation time, owning user,
147 command name, memory usage, controlling terminal etc. (the complete
148 list is in the struct acct in <file:include/linux/acct.h>). It is
149 up to the user level program to do useful things with this
150 information. This is generally a good idea, so say Y.
152 config BSD_PROCESS_ACCT_V3
153 bool "BSD Process Accounting version 3 file format"
154 depends on BSD_PROCESS_ACCT
157 If you say Y here, the process accounting information is written
158 in a new file format that also logs the process IDs of each
159 process and it's parent. Note that this file format is incompatible
160 with previous v0/v1/v2 file formats, so you will need updated tools
161 for processing it. A preliminary version of these tools is available
162 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
165 bool "Sysctl support"
167 The sysctl interface provides a means of dynamically changing
168 certain kernel parameters and variables on the fly without requiring
169 a recompile of the kernel or reboot of the system. The primary
170 interface consists of a system call, but if you say Y to "/proc
171 file system support", a tree of modifiable sysctl entries will be
172 generated beneath the /proc/sys directory. They are explained in the
173 files in <file:Documentation/sysctl/>. Note that enabling this
174 option will enlarge the kernel by at least 8 KB.
176 As it is generally a good thing, you should say Y here unless
177 building a kernel for install/rescue disks or your system is very
181 bool "Auditing support"
183 default y if SECURITY_SELINUX
185 Enable auditing infrastructure that can be used with another
186 kernel subsystem, such as SELinux (which requires this for
187 logging of avc messages output). Does not do system-call
188 auditing without CONFIG_AUDITSYSCALL.
191 bool "Enable system-call auditing support"
192 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
193 default y if SECURITY_SELINUX
195 Enable low-overhead system-call auditing infrastructure that
196 can be used independently or with another kernel subsystem,
200 bool "Kernel .config support"
202 This option enables the complete Linux kernel ".config" file
203 contents to be saved in the kernel. It provides documentation
204 of which kernel options are used in a running kernel or in an
205 on-disk kernel. This information can be extracted from the kernel
206 image file with the script scripts/extract-ikconfig and used as
207 input to rebuild the current kernel or to build another kernel.
208 It can also be extracted from a running kernel by reading
209 /proc/config.gz if enabled (below).
212 bool "Enable access to .config through /proc/config.gz"
213 depends on IKCONFIG && PROC_FS
215 This option enables access to the kernel configuration file
216 through /proc/config.gz.
219 bool "Cpuset support"
222 This option will let you create and manage CPUSETs which
223 allow dynamically partitioning a system into sets of CPUs and
224 Memory Nodes and assigning tasks to run only within those sets.
225 This is primarily useful on large SMP or NUMA systems.
231 config CC_OPTIMIZE_FOR_SIZE
232 bool "Optimize for size (Look out for broken compilers!)"
234 depends on ARM || H8300 || EXPERIMENTAL
236 Enabling this option will pass "-Os" instead of "-O2" to gcc
237 resulting in a smaller kernel.
239 WARNING: some versions of gcc may generate incorrect code with this
240 option. If problems are observed, a gcc upgrade may be needed.
245 bool "Configure standard kernel features (for small systems)"
247 This option allows certain base kernel options and settings
248 to be disabled or tweaked. This is for specialized
249 environments which can tolerate a "non-standard" kernel.
250 Only use this if you really know what you are doing.
253 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
256 Say Y here to let the kernel print out symbolic crash information and
257 symbolic stack backtraces. This increases the size of the kernel
258 somewhat, as all symbols have to be loaded into the kernel image.
261 bool "Include all symbols in kallsyms"
262 depends on DEBUG_KERNEL && KALLSYMS
264 Normally kallsyms only contains the symbols of functions, for nicer
265 OOPS messages. Some debuggers can use kallsyms for other
266 symbols too: say Y here to include all symbols, if you need them
267 and you don't care about adding 300k to the size of your kernel.
271 config KALLSYMS_EXTRA_PASS
272 bool "Do an extra kallsyms pass"
275 If kallsyms is not working correctly, the build will fail with
276 inconsistent kallsyms data. If that occurs, log a bug report and
277 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
278 Always say N here unless you find a bug in kallsyms, which must be
279 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
280 you wait for kallsyms to be fixed.
284 bool "Support for hot-pluggable devices" if EMBEDDED
287 This option is provided for the case where no hotplug or uevent
288 capabilities is wanted by the kernel. You should only consider
289 disabling this option for embedded systems that do not use modules, a
290 dynamic /dev tree, or dynamic device discovery. Just say Y.
294 bool "Enable support for printk" if EMBEDDED
296 This option enables normal printk support. Removing it
297 eliminates most of the message strings from the kernel image
298 and makes the kernel more or less silent. As this makes it
299 very difficult to diagnose system problems, saying N here is
300 strongly discouraged.
303 bool "BUG() support" if EMBEDDED
306 Disabling this option eliminates support for BUG and WARN, reducing
307 the size of your kernel image and potentially quietly ignoring
308 numerous fatal conditions. You should only consider disabling this
309 option for embedded systems with no facilities for reporting errors.
314 bool "Enable full-sized data structures for core" if EMBEDDED
316 Disabling this option reduces the size of miscellaneous core
317 kernel data structures. This saves memory on small machines,
318 but may reduce performance.
321 bool "Enable futex support" if EMBEDDED
324 Disabling this option will cause the kernel to be built without
325 support for "fast userspace mutexes". The resulting kernel may not
326 run glibc-based applications correctly.
329 bool "Enable eventpoll support" if EMBEDDED
332 Disabling this option will cause the kernel to be built without
333 support for epoll family of system calls.
336 bool "Use full shmem filesystem" if EMBEDDED
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
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
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
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
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.
385 bool "Use full SLAB allocator" if EMBEDDED
387 Disabling this replaces the advanced SLAB allocator and
388 kmalloc support with the drastically simpler SLOB allocator.
389 SLOB is more space efficient but does not scale well and is
390 more susceptible to fragmentation.
392 endmenu # General setup
400 default 0 if BASE_FULL
401 default 1 if !BASE_FULL
407 menu "Loadable module support"
410 bool "Enable loadable module support"
412 Kernel modules are small pieces of compiled code which can
413 be inserted in the running kernel, rather than being
414 permanently built into the kernel. You use the "modprobe"
415 tool to add (and sometimes remove) them. If you say Y here,
416 many parts of the kernel can be built as modules (by
417 answering M instead of Y where indicated): this is most
418 useful for infrequently used options which are not required
419 for booting. For more information, see the man pages for
420 modprobe, lsmod, modinfo, insmod and rmmod.
422 If you say Y here, you will need to run "make
423 modules_install" to put the modules under /lib/modules/
424 where modprobe can find them (you may need to be root to do
430 bool "Module unloading"
433 Without this option you will not be able to unload any
434 modules (note that some modules may not be unloadable
435 anyway), which makes your kernel slightly smaller and
436 simpler. If unsure, say Y.
438 config MODULE_FORCE_UNLOAD
439 bool "Forced module unloading"
440 depends on MODULE_UNLOAD && EXPERIMENTAL
442 This option allows you to force a module to unload, even if the
443 kernel believes it is unsafe: the kernel will remove the module
444 without waiting for anyone to stop using it (using the -f option to
445 rmmod). This is mainly for kernel developers and desperate users.
448 config OBSOLETE_MODPARM
453 You need this option to use module parameters on modules which
454 have not been converted to the new module parameter system yet.
458 bool "Module versioning support"
461 Usually, you have to use modules compiled with your kernel.
462 Saying Y here makes it sometimes possible to use modules
463 compiled for different kernels, by adding enough information
464 to the modules to (hopefully) spot any changes which would
465 make them incompatible with the kernel you are running. If
468 config MODULE_SRCVERSION_ALL
469 bool "Source checksum for all modules"
472 Modules which contain a MODULE_VERSION get an extra "srcversion"
473 field inserted into their modinfo section, which contains a
474 sum of the source files which made it. This helps maintainers
475 see exactly which source was used to build a module (since
476 others sometimes change the module source without updating
477 the version). With this option, such a "srcversion" field
478 will be created for all modules. If unsure, say N.
481 bool "Automatic kernel module loading"
484 Normally when you have selected some parts of the kernel to
485 be created as kernel modules, you must load them (using the
486 "modprobe" command) before you can use them. If you say Y
487 here, some parts of the kernel will be able to load modules
488 automatically: when a part of the kernel needs a module, it
489 runs modprobe with the appropriate arguments, thereby
490 loading the module if it is available. If unsure, say Y.
495 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
497 Need stop_machine() primitive.
501 source "block/Kconfig"
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