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1 config DEFCONFIG_LIST
2 string
3 option defconfig_list
4 default "/lib/modules/$UNAME_RELEASE/.config"
5 default "/etc/kernel-config"
6 default "/boot/config-$UNAME_RELEASE"
7 default "arch/$ARCH/defconfig"
9 menu "Code maturity level options"
11 config EXPERIMENTAL
12 bool "Prompt for development and/or incomplete code/drivers"
13 ---help---
14 Some of the various things that Linux supports (such as network
15 drivers, file systems, network protocols, etc.) can be in a state
16 of development where the functionality, stability, or the level of
17 testing is not yet high enough for general use. This is usually
18 known as the "alpha-test" phase among developers. If a feature is
19 currently in alpha-test, then the developers usually discourage
20 uninformed widespread use of this feature by the general public to
21 avoid "Why doesn't this work?" type mail messages. However, active
22 testing and use of these systems is welcomed. Just be aware that it
23 may not meet the normal level of reliability or it may fail to work
24 in some special cases. Detailed bug reports from people familiar
25 with the kernel internals are usually welcomed by the developers
26 (before submitting bug reports, please read the documents
27 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
28 <file:Documentation/BUG-HUNTING>, and
29 <file:Documentation/oops-tracing.txt> in the kernel source).
31 This option will also make obsoleted drivers available. These are
32 drivers that have been replaced by something else, and/or are
33 scheduled to be removed in a future kernel release.
35 Unless you intend to help test and develop a feature or driver that
36 falls into this category, or you have a situation that requires
37 using these features, you should probably say N here, which will
38 cause the configurator to present you with fewer choices. If
39 you say Y here, you will be offered the choice of using features or
40 drivers that are currently considered to be in the alpha-test phase.
42 config BROKEN
43 bool
45 config BROKEN_ON_SMP
46 bool
47 depends on BROKEN || !SMP
48 default y
50 config LOCK_KERNEL
51 bool
52 depends on SMP || PREEMPT
53 default y
55 config INIT_ENV_ARG_LIMIT
56 int
57 default 32 if !UML
58 default 128 if UML
59 help
60 Maximum of each of the number of arguments and environment
61 variables passed to init from the kernel command line.
63 endmenu
65 menu "General setup"
67 config LOCALVERSION
68 string "Local version - append to kernel release"
69 help
70 Append an extra string to the end of your kernel version.
71 This will show up when you type uname, for example.
72 The string you set here will be appended after the contents of
73 any files with a filename matching localversion* in your
74 object and source tree, in that order. Your total string can
75 be a maximum of 64 characters.
77 config LOCALVERSION_AUTO
78 bool "Automatically append version information to the version string"
79 default y
80 help
81 This will try to automatically determine if the current tree is a
82 release tree by looking for git tags that
83 belong to the current top of tree revision.
85 A string of the format -gxxxxxxxx will be added to the localversion
86 if a git based tree is found. The string generated by this will be
87 appended after any matching localversion* files, and after the value
88 set in CONFIG_LOCALVERSION
90 Note: This requires Perl, and a git repository, but not necessarily
91 the git or cogito tools to be installed.
93 config SWAP
94 bool "Support for paging of anonymous memory (swap)"
95 depends on MMU
96 default y
97 help
98 This option allows you to choose whether you want to have support
99 for so called swap devices or swap files in your kernel that are
100 used to provide more virtual memory than the actual RAM present
101 in your computer. If unsure say Y.
103 config SYSVIPC
104 bool "System V IPC"
105 ---help---
106 Inter Process Communication is a suite of library functions and
107 system calls which let processes (running programs) synchronize and
108 exchange information. It is generally considered to be a good thing,
109 and some programs won't run unless you say Y here. In particular, if
110 you want to run the DOS emulator dosemu under Linux (read the
111 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
112 you'll need to say Y here.
114 You can find documentation about IPC with "info ipc" and also in
115 section 6.4 of the Linux Programmer's Guide, available from
116 <http://www.tldp.org/guides.html>.
118 config POSIX_MQUEUE
119 bool "POSIX Message Queues"
120 depends on NET && EXPERIMENTAL
121 ---help---
122 POSIX variant of message queues is a part of IPC. In POSIX message
123 queues every message has a priority which decides about succession
124 of receiving it by a process. If you want to compile and run
125 programs written e.g. for Solaris with use of its POSIX message
126 queues (functions mq_*) say Y here. To use this feature you will
127 also need mqueue library, available from
128 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
130 POSIX message queues are visible as a filesystem called 'mqueue'
131 and can be mounted somewhere if you want to do filesystem
132 operations on message queues.
134 If unsure, say Y.
136 config BSD_PROCESS_ACCT
137 bool "BSD Process Accounting"
138 help
139 If you say Y here, a user level program will be able to instruct the
140 kernel (via a special system call) to write process accounting
141 information to a file: whenever a process exits, information about
142 that process will be appended to the file by the kernel. The
143 information includes things such as creation time, owning user,
144 command name, memory usage, controlling terminal etc. (the complete
145 list is in the struct acct in <file:include/linux/acct.h>). It is
146 up to the user level program to do useful things with this
147 information. This is generally a good idea, so say Y.
149 config BSD_PROCESS_ACCT_V3
150 bool "BSD Process Accounting version 3 file format"
151 depends on BSD_PROCESS_ACCT
152 default n
153 help
154 If you say Y here, the process accounting information is written
155 in a new file format that also logs the process IDs of each
156 process and it's parent. Note that this file format is incompatible
157 with previous v0/v1/v2 file formats, so you will need updated tools
158 for processing it. A preliminary version of these tools is available
159 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
161 config TASKSTATS
162 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
163 depends on NET
164 default n
165 help
166 Export selected statistics for tasks/processes through the
167 generic netlink interface. Unlike BSD process accounting, the
168 statistics are available during the lifetime of tasks/processes as
169 responses to commands. Like BSD accounting, they are sent to user
170 space on task exit.
172 Say N if unsure.
174 config TASK_DELAY_ACCT
175 bool "Enable per-task delay accounting (EXPERIMENTAL)"
176 depends on TASKSTATS
177 help
178 Collect information on time spent by a task waiting for system
179 resources like cpu, synchronous block I/O completion and swapping
180 in pages. Such statistics can help in setting a task's priorities
181 relative to other tasks for cpu, io, rss limits etc.
183 Say N if unsure.
185 config AUDIT
186 bool "Auditing support"
187 depends on NET
188 help
189 Enable auditing infrastructure that can be used with another
190 kernel subsystem, such as SELinux (which requires this for
191 logging of avc messages output). Does not do system-call
192 auditing without CONFIG_AUDITSYSCALL.
194 config AUDITSYSCALL
195 bool "Enable system-call auditing support"
196 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
197 default y if SECURITY_SELINUX
198 help
199 Enable low-overhead system-call auditing infrastructure that
200 can be used independently or with another kernel subsystem,
201 such as SELinux. To use audit's filesystem watch feature, please
202 ensure that INOTIFY is configured.
204 config IKCONFIG
205 bool "Kernel .config support"
206 ---help---
207 This option enables the complete Linux kernel ".config" file
208 contents to be saved in the kernel. It provides documentation
209 of which kernel options are used in a running kernel or in an
210 on-disk kernel. This information can be extracted from the kernel
211 image file with the script scripts/extract-ikconfig and used as
212 input to rebuild the current kernel or to build another kernel.
213 It can also be extracted from a running kernel by reading
214 /proc/config.gz if enabled (below).
216 config IKCONFIG_PROC
217 bool "Enable access to .config through /proc/config.gz"
218 depends on IKCONFIG && PROC_FS
219 ---help---
220 This option enables access to the kernel configuration file
221 through /proc/config.gz.
223 config CPUSETS
224 bool "Cpuset support"
225 depends on SMP
226 help
227 This option will let you create and manage CPUSETs which
228 allow dynamically partitioning a system into sets of CPUs and
229 Memory Nodes and assigning tasks to run only within those sets.
230 This is primarily useful on large SMP or NUMA systems.
232 Say N if unsure.
234 config RELAY
235 bool "Kernel->user space relay support (formerly relayfs)"
236 help
237 This option enables support for relay interface support in
238 certain file systems (such as debugfs).
239 It is designed to provide an efficient mechanism for tools and
240 facilities to relay large amounts of data from kernel space to
241 user space.
243 If unsure, say N.
245 source "usr/Kconfig"
247 config CC_OPTIMIZE_FOR_SIZE
248 bool "Optimize for size (Look out for broken compilers!)"
249 default y
250 depends on ARM || H8300 || EXPERIMENTAL
251 help
252 Enabling this option will pass "-Os" instead of "-O2" to gcc
253 resulting in a smaller kernel.
255 WARNING: some versions of gcc may generate incorrect code with this
256 option. If problems are observed, a gcc upgrade may be needed.
258 If unsure, say N.
260 menuconfig EMBEDDED
261 bool "Configure standard kernel features (for small systems)"
262 help
263 This option allows certain base kernel options and settings
264 to be disabled or tweaked. This is for specialized
265 environments which can tolerate a "non-standard" kernel.
266 Only use this if you really know what you are doing.
268 config UID16
269 bool "Enable 16-bit UID system calls" if EMBEDDED
270 depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
271 default y
272 help
273 This enables the legacy 16-bit UID syscall wrappers.
275 config SYSCTL
276 bool
278 config SYSCTL_SYSCALL
279 bool "Sysctl syscall support"
280 default n
281 select SYSCTL
282 ---help---
283 Enable the deprecated sysctl system call. sys_sysctl uses
284 binary paths that have been found to be a major pain to maintain
285 and use. The interface in /proc/sys is now the primary and what
286 everyone uses.
288 Nothing has been using the binary sysctl interface for some time
289 time now so nothing should break if you disable sysctl syscall
290 support, and you kernel will get marginally smaller.
292 Unless you have an application that uses the sys_syscall interface
293 you should probably say N here.
295 config KALLSYMS
296 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
297 default y
298 help
299 Say Y here to let the kernel print out symbolic crash information and
300 symbolic stack backtraces. This increases the size of the kernel
301 somewhat, as all symbols have to be loaded into the kernel image.
303 config KALLSYMS_ALL
304 bool "Include all symbols in kallsyms"
305 depends on DEBUG_KERNEL && KALLSYMS
306 help
307 Normally kallsyms only contains the symbols of functions, for nicer
308 OOPS messages. Some debuggers can use kallsyms for other
309 symbols too: say Y here to include all symbols, if you need them
310 and you don't care about adding 300k to the size of your kernel.
312 Say N.
314 config KALLSYMS_EXTRA_PASS
315 bool "Do an extra kallsyms pass"
316 depends on KALLSYMS
317 help
318 If kallsyms is not working correctly, the build will fail with
319 inconsistent kallsyms data. If that occurs, log a bug report and
320 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
321 Always say N here unless you find a bug in kallsyms, which must be
322 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
323 you wait for kallsyms to be fixed.
326 config HOTPLUG
327 bool "Support for hot-pluggable devices" if EMBEDDED
328 default y
329 help
330 This option is provided for the case where no hotplug or uevent
331 capabilities is wanted by the kernel. You should only consider
332 disabling this option for embedded systems that do not use modules, a
333 dynamic /dev tree, or dynamic device discovery. Just say Y.
335 config PRINTK
336 default y
337 bool "Enable support for printk" if EMBEDDED
338 help
339 This option enables normal printk support. Removing it
340 eliminates most of the message strings from the kernel image
341 and makes the kernel more or less silent. As this makes it
342 very difficult to diagnose system problems, saying N here is
343 strongly discouraged.
345 config BUG
346 bool "BUG() support" if EMBEDDED
347 default y
348 help
349 Disabling this option eliminates support for BUG and WARN, reducing
350 the size of your kernel image and potentially quietly ignoring
351 numerous fatal conditions. You should only consider disabling this
352 option for embedded systems with no facilities for reporting errors.
353 Just say Y.
355 config ELF_CORE
356 default y
357 bool "Enable ELF core dumps" if EMBEDDED
358 help
359 Enable support for generating core dumps. Disabling saves about 4k.
361 config BASE_FULL
362 default y
363 bool "Enable full-sized data structures for core" if EMBEDDED
364 help
365 Disabling this option reduces the size of miscellaneous core
366 kernel data structures. This saves memory on small machines,
367 but may reduce performance.
369 config FUTEX
370 bool "Enable futex support" if EMBEDDED
371 default y
372 select RT_MUTEXES
373 help
374 Disabling this option will cause the kernel to be built without
375 support for "fast userspace mutexes". The resulting kernel may not
376 run glibc-based applications correctly.
378 config EPOLL
379 bool "Enable eventpoll support" if EMBEDDED
380 default y
381 help
382 Disabling this option will cause the kernel to be built without
383 support for epoll family of system calls.
385 config SHMEM
386 bool "Use full shmem filesystem" if EMBEDDED
387 default y
388 depends on MMU
389 help
390 The shmem is an internal filesystem used to manage shared memory.
391 It is backed by swap and manages resource limits. It is also exported
392 to userspace as tmpfs if TMPFS is enabled. Disabling this
393 option replaces shmem and tmpfs with the much simpler ramfs code,
394 which may be appropriate on small systems without swap.
396 config SLAB
397 default y
398 bool "Use full SLAB allocator" if EMBEDDED
399 help
400 Disabling this replaces the advanced SLAB allocator and
401 kmalloc support with the drastically simpler SLOB allocator.
402 SLOB is more space efficient but does not scale well and is
403 more susceptible to fragmentation.
405 config VM_EVENT_COUNTERS
406 default y
407 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
408 help
409 VM event counters are only needed to for event counts to be
410 shown. They have no function for the kernel itself. This
411 option allows the disabling of the VM event counters.
412 /proc/vmstat will only show page counts.
414 endmenu # General setup
416 config RT_MUTEXES
417 boolean
418 select PLIST
420 config TINY_SHMEM
421 default !SHMEM
422 bool
424 config BASE_SMALL
425 int
426 default 0 if BASE_FULL
427 default 1 if !BASE_FULL
429 config SLOB
430 default !SLAB
431 bool
433 menu "Loadable module support"
435 config MODULES
436 bool "Enable loadable module support"
437 help
438 Kernel modules are small pieces of compiled code which can
439 be inserted in the running kernel, rather than being
440 permanently built into the kernel. You use the "modprobe"
441 tool to add (and sometimes remove) them. If you say Y here,
442 many parts of the kernel can be built as modules (by
443 answering M instead of Y where indicated): this is most
444 useful for infrequently used options which are not required
445 for booting. For more information, see the man pages for
446 modprobe, lsmod, modinfo, insmod and rmmod.
448 If you say Y here, you will need to run "make
449 modules_install" to put the modules under /lib/modules/
450 where modprobe can find them (you may need to be root to do
451 this).
453 If unsure, say Y.
455 config MODULE_UNLOAD
456 bool "Module unloading"
457 depends on MODULES
458 help
459 Without this option you will not be able to unload any
460 modules (note that some modules may not be unloadable
461 anyway), which makes your kernel slightly smaller and
462 simpler. If unsure, say Y.
464 config MODULE_FORCE_UNLOAD
465 bool "Forced module unloading"
466 depends on MODULE_UNLOAD && EXPERIMENTAL
467 help
468 This option allows you to force a module to unload, even if the
469 kernel believes it is unsafe: the kernel will remove the module
470 without waiting for anyone to stop using it (using the -f option to
471 rmmod). This is mainly for kernel developers and desperate users.
472 If unsure, say N.
474 config MODVERSIONS
475 bool "Module versioning support"
476 depends on MODULES
477 help
478 Usually, you have to use modules compiled with your kernel.
479 Saying Y here makes it sometimes possible to use modules
480 compiled for different kernels, by adding enough information
481 to the modules to (hopefully) spot any changes which would
482 make them incompatible with the kernel you are running. If
483 unsure, say N.
485 config MODULE_SRCVERSION_ALL
486 bool "Source checksum for all modules"
487 depends on MODULES
488 help
489 Modules which contain a MODULE_VERSION get an extra "srcversion"
490 field inserted into their modinfo section, which contains a
491 sum of the source files which made it. This helps maintainers
492 see exactly which source was used to build a module (since
493 others sometimes change the module source without updating
494 the version). With this option, such a "srcversion" field
495 will be created for all modules. If unsure, say N.
497 config KMOD
498 bool "Automatic kernel module loading"
499 depends on MODULES
500 help
501 Normally when you have selected some parts of the kernel to
502 be created as kernel modules, you must load them (using the
503 "modprobe" command) before you can use them. If you say Y
504 here, some parts of the kernel will be able to load modules
505 automatically: when a part of the kernel needs a module, it
506 runs modprobe with the appropriate arguments, thereby
507 loading the module if it is available. If unsure, say Y.
509 config STOP_MACHINE
510 bool
511 default y
512 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
513 help
514 Need stop_machine() primitive.
515 endmenu
517 menu "Block layer"
518 source "block/Kconfig"
519 endmenu