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24 drivers that have been replaced by something else, and/or are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.
39 depends on BROKEN || !SMP
44 depends on SMP || PREEMPT
47 config INIT_ENV_ARG_LIMIT
49 default 32 if !USERMODE
50 default 128 if USERMODE
52 Maximum of each of the number of arguments and environment
53 variables passed to init from the kernel command line.
60 string "Local version - append to kernel release"
62 Append an extra string to the end of your kernel version.
63 This will show up when you type uname, for example.
64 The string you set here will be appended after the contents of
65 any files with a filename matching localversion* in your
66 object and source tree, in that order. Your total string can
67 be a maximum of 64 characters.
69 config LOCALVERSION_AUTO
70 bool "Automatically append version information to the version string"
73 This will try to automatically determine if the current tree is a
74 release tree by looking for git tags that
75 belong to the current top of tree revision.
77 A string of the format -gxxxxxxxx will be added to the localversion
78 if a git based tree is found. The string generated by this will be
79 appended after any matching localversion* files, and after the value
80 set in CONFIG_LOCALVERSION
82 Note: This requires Perl, and a git repository, but not necessarily
83 the git or cogito tools to be installed.
86 bool "Support for paging of anonymous memory (swap)"
90 This option allows you to choose whether you want to have support
91 for so called swap devices or swap files in your kernel that are
92 used to provide more virtual memory than the actual RAM present
93 in your computer. If unsure say Y.
98 Inter Process Communication is a suite of library functions and
99 system calls which let processes (running programs) synchronize and
100 exchange information. It is generally considered to be a good thing,
101 and some programs won't run unless you say Y here. In particular, if
102 you want to run the DOS emulator dosemu under Linux (read the
103 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
104 you'll need to say Y here.
106 You can find documentation about IPC with "info ipc" and also in
107 section 6.4 of the Linux Programmer's Guide, available from
108 <http://www.tldp.org/guides.html>.
111 bool "POSIX Message Queues"
112 depends on NET && EXPERIMENTAL
114 POSIX variant of message queues is a part of IPC. In POSIX message
115 queues every message has a priority which decides about succession
116 of receiving it by a process. If you want to compile and run
117 programs written e.g. for Solaris with use of its POSIX message
118 queues (functions mq_*) say Y here. To use this feature you will
119 also need mqueue library, available from
120 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
122 POSIX message queues are visible as a filesystem called 'mqueue'
123 and can be mounted somewhere if you want to do filesystem
124 operations on message queues.
128 config BSD_PROCESS_ACCT
129 bool "BSD Process Accounting"
131 If you say Y here, a user level program will be able to instruct the
132 kernel (via a special system call) to write process accounting
133 information to a file: whenever a process exits, information about
134 that process will be appended to the file by the kernel. The
135 information includes things such as creation time, owning user,
136 command name, memory usage, controlling terminal etc. (the complete
137 list is in the struct acct in <file:include/linux/acct.h>). It is
138 up to the user level program to do useful things with this
139 information. This is generally a good idea, so say Y.
141 config BSD_PROCESS_ACCT_V3
142 bool "BSD Process Accounting version 3 file format"
143 depends on BSD_PROCESS_ACCT
146 If you say Y here, the process accounting information is written
147 in a new file format that also logs the process IDs of each
148 process and it's parent. Note that this file format is incompatible
149 with previous v0/v1/v2 file formats, so you will need updated tools
150 for processing it. A preliminary version of these tools is available
151 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
154 bool "Sysctl support"
156 The sysctl interface provides a means of dynamically changing
157 certain kernel parameters and variables on the fly without requiring
158 a recompile of the kernel or reboot of the system. The primary
159 interface consists of a system call, but if you say Y to "/proc
160 file system support", a tree of modifiable sysctl entries will be
161 generated beneath the /proc/sys directory. They are explained in the
162 files in <file:Documentation/sysctl/>. Note that enabling this
163 option will enlarge the kernel by at least 8 KB.
165 As it is generally a good thing, you should say Y here unless
166 building a kernel for install/rescue disks or your system is very
170 bool "Auditing support"
172 default y if SECURITY_SELINUX
174 Enable auditing infrastructure that can be used with another
175 kernel subsystem, such as SELinux (which requires this for
176 logging of avc messages output). Does not do system-call
177 auditing without CONFIG_AUDITSYSCALL.
180 bool "Enable system-call auditing support"
181 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
182 default y if SECURITY_SELINUX
184 Enable low-overhead system-call auditing infrastructure that
185 can be used independently or with another kernel subsystem,
189 bool "Kernel .config support"
191 This option enables the complete Linux kernel ".config" file
192 contents to be saved in the kernel. It provides documentation
193 of which kernel options are used in a running kernel or in an
194 on-disk kernel. This information can be extracted from the kernel
195 image file with the script scripts/extract-ikconfig and used as
196 input to rebuild the current kernel or to build another kernel.
197 It can also be extracted from a running kernel by reading
198 /proc/config.gz if enabled (below).
201 bool "Enable access to .config through /proc/config.gz"
202 depends on IKCONFIG && PROC_FS
204 This option enables access to the kernel configuration file
205 through /proc/config.gz.
208 bool "Cpuset support"
211 This option will let you create and manage CPUSETs which
212 allow dynamically partitioning a system into sets of CPUs and
213 Memory Nodes and assigning tasks to run only within those sets.
214 This is primarily useful on large SMP or NUMA systems.
221 bool "Enable 16-bit UID system calls" if EMBEDDED
222 depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
225 This enables the legacy 16-bit UID syscall wrappers.
230 bool "Enable VM86 support" if EMBEDDED
232 This option is required by programs like DOSEMU to run 16-bit legacy
233 code on X86 processors. It also may be needed by software like
234 XFree86 to initialize some video cards via BIOS. Disabling this
235 option saves about 6k.
237 config CC_OPTIMIZE_FOR_SIZE
238 bool "Optimize for size (Look out for broken compilers!)"
240 depends on ARM || H8300 || EXPERIMENTAL
242 Enabling this option will pass "-Os" instead of "-O2" to gcc
243 resulting in a smaller kernel.
245 WARNING: some versions of gcc may generate incorrect code with this
246 option. If problems are observed, a gcc upgrade may be needed.
251 bool "Configure standard kernel features (for small systems)"
253 This option allows certain base kernel options and settings
254 to be disabled or tweaked. This is for specialized
255 environments which can tolerate a "non-standard" kernel.
256 Only use this if you really know what you are doing.
259 bool "Load all symbols for debugging/kksymoops" if EMBEDDED
262 Say Y here to let the kernel print out symbolic crash information and
263 symbolic stack backtraces. This increases the size of the kernel
264 somewhat, as all symbols have to be loaded into the kernel image.
267 bool "Include all symbols in kallsyms"
268 depends on DEBUG_KERNEL && KALLSYMS
270 Normally kallsyms only contains the symbols of functions, for nicer
271 OOPS messages. Some debuggers can use kallsyms for other
272 symbols too: say Y here to include all symbols, if you need them
273 and you don't care about adding 300k to the size of your kernel.
277 config KALLSYMS_EXTRA_PASS
278 bool "Do an extra kallsyms pass"
281 If kallsyms is not working correctly, the build will fail with
282 inconsistent kallsyms data. If that occurs, log a bug report and
283 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
284 Always say N here unless you find a bug in kallsyms, which must be
285 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
286 you wait for kallsyms to be fixed.
290 bool "Support for hot-pluggable devices" if EMBEDDED
293 This option is provided for the case where no hotplug or uevent
294 capabilities is wanted by the kernel. You should only consider
295 disabling this option for embedded systems that do not use modules, a
296 dynamic /dev tree, or dynamic device discovery. Just say Y.
300 bool "Enable support for printk" if EMBEDDED
302 This option enables normal printk support. Removing it
303 eliminates most of the message strings from the kernel image
304 and makes the kernel more or less silent. As this makes it
305 very difficult to diagnose system problems, saying N here is
306 strongly discouraged.
309 bool "BUG() support" if EMBEDDED
312 Disabling this option eliminates support for BUG and WARN, reducing
313 the size of your kernel image and potentially quietly ignoring
314 numerous fatal conditions. You should only consider disabling this
315 option for embedded systems with no facilities for reporting errors.
320 bool "Enable ELF core dumps" if EMBEDDED
322 Enable support for generating core dumps. Disabling saves about 4k.
326 bool "Enable full-sized data structures for core" if EMBEDDED
328 Disabling this option reduces the size of miscellaneous core
329 kernel data structures. This saves memory on small machines,
330 but may reduce performance.
333 bool "Enable futex support" if EMBEDDED
336 Disabling this option will cause the kernel to be built without
337 support for "fast userspace mutexes". The resulting kernel may not
338 run glibc-based applications correctly.
341 bool "Enable eventpoll support" if EMBEDDED
344 Disabling this option will cause the kernel to be built without
345 support for epoll family of system calls.
348 bool "Use full shmem filesystem" if EMBEDDED
352 The shmem is an internal filesystem used to manage shared memory.
353 It is backed by swap and manages resource limits. It is also exported
354 to userspace as tmpfs if TMPFS is enabled. Disabling this
355 option replaces shmem and tmpfs with the much simpler ramfs code,
356 which may be appropriate on small systems without swap.
358 config CC_ALIGN_FUNCTIONS
359 int "Function alignment" if EMBEDDED
362 Align the start of functions to the next power-of-two greater than n,
363 skipping up to n bytes. For instance, 32 aligns functions
364 to the next 32-byte boundary, but 24 would align to the next
365 32-byte boundary only if this can be done by skipping 23 bytes or less.
366 Zero means use compiler's default.
368 config CC_ALIGN_LABELS
369 int "Label alignment" if EMBEDDED
372 Align all branch targets to a power-of-two boundary, skipping
373 up to n bytes like ALIGN_FUNCTIONS. This option can easily
374 make code slower, because it must insert dummy operations for
375 when the branch target is reached in the usual flow of the code.
376 Zero means use compiler's default.
378 config CC_ALIGN_LOOPS
379 int "Loop alignment" if EMBEDDED
382 Align loops to a power-of-two boundary, skipping up to n bytes.
383 Zero means use compiler's default.
385 config CC_ALIGN_JUMPS
386 int "Jump alignment" if EMBEDDED
389 Align branch targets to a power-of-two boundary, for branch
390 targets where the targets can only be reached by jumping,
391 skipping up to n bytes like ALIGN_FUNCTIONS. In this case,
392 no dummy operations need be executed.
393 Zero means use compiler's default.
397 bool "Use full SLAB allocator" if EMBEDDED
399 Disabling this replaces the advanced SLAB allocator and
400 kmalloc support with the drastically simpler SLOB allocator.
401 SLOB is more space efficient but does not scale well and is
402 more susceptible to fragmentation.
404 endmenu # General setup
412 default 0 if BASE_FULL
413 default 1 if !BASE_FULL
419 config OBSOLETE_INTERMODULE
422 menu "Loadable module support"
425 bool "Enable loadable module support"
427 Kernel modules are small pieces of compiled code which can
428 be inserted in the running kernel, rather than being
429 permanently built into the kernel. You use the "modprobe"
430 tool to add (and sometimes remove) them. If you say Y here,
431 many parts of the kernel can be built as modules (by
432 answering M instead of Y where indicated): this is most
433 useful for infrequently used options which are not required
434 for booting. For more information, see the man pages for
435 modprobe, lsmod, modinfo, insmod and rmmod.
437 If you say Y here, you will need to run "make
438 modules_install" to put the modules under /lib/modules/
439 where modprobe can find them (you may need to be root to do
445 bool "Module unloading"
448 Without this option you will not be able to unload any
449 modules (note that some modules may not be unloadable
450 anyway), which makes your kernel slightly smaller and
451 simpler. If unsure, say Y.
453 config MODULE_FORCE_UNLOAD
454 bool "Forced module unloading"
455 depends on MODULE_UNLOAD && EXPERIMENTAL
457 This option allows you to force a module to unload, even if the
458 kernel believes it is unsafe: the kernel will remove the module
459 without waiting for anyone to stop using it (using the -f option to
460 rmmod). This is mainly for kernel developers and desperate users.
463 config OBSOLETE_MODPARM
468 You need this option to use module parameters on modules which
469 have not been converted to the new module parameter system yet.
473 bool "Module versioning support"
476 Usually, you have to use modules compiled with your kernel.
477 Saying Y here makes it sometimes possible to use modules
478 compiled for different kernels, by adding enough information
479 to the modules to (hopefully) spot any changes which would
480 make them incompatible with the kernel you are running. If
483 config MODULE_SRCVERSION_ALL
484 bool "Source checksum for all modules"
487 Modules which contain a MODULE_VERSION get an extra "srcversion"
488 field inserted into their modinfo section, which contains a
489 sum of the source files which made it. This helps maintainers
490 see exactly which source was used to build a module (since
491 others sometimes change the module source without updating
492 the version). With this option, such a "srcversion" field
493 will be created for all modules. If unsure, say N.
496 bool "Automatic kernel module loading"
499 Normally when you have selected some parts of the kernel to
500 be created as kernel modules, you must load them (using the
501 "modprobe" command) before you can use them. If you say Y
502 here, some parts of the kernel will be able to load modules
503 automatically: when a part of the kernel needs a module, it
504 runs modprobe with the appropriate arguments, thereby
505 loading the module if it is available. If unsure, say Y.
510 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
512 Need stop_machine() primitive.
516 source "block/Kconfig"