5 default "/lib/modules/$UNAME_RELEASE/.config"
6 default "/etc/kernel-config"
7 default "/boot/config-$UNAME_RELEASE"
8 default "arch/$ARCH/defconfig"
10 menu "Code maturity level options"
13 bool "Prompt for development and/or incomplete code/drivers"
15 Some of the various things that Linux supports (such as network
16 drivers, file systems, network protocols, etc.) can be in a state
17 of development where the functionality, stability, or the level of
18 testing is not yet high enough for general use. This is usually
19 known as the "alpha-test" phase among developers. If a feature is
20 currently in alpha-test, then the developers usually discourage
21 uninformed widespread use of this feature by the general public to
22 avoid "Why doesn't this work?" type mail messages. However, active
23 testing and use of these systems is welcomed. Just be aware that it
24 may not meet the normal level of reliability or it may fail to work
25 in some special cases. Detailed bug reports from people familiar
26 with the kernel internals are usually welcomed by the developers
27 (before submitting bug reports, please read the documents
28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>,
29 <file:Documentation/BUG-HUNTING>, and
30 <file:Documentation/oops-tracing.txt> in the kernel source).
32 This option will also make obsoleted drivers available. These are
33 drivers that have been replaced by something else, and/or are
34 scheduled to be removed in a future kernel release.
36 Unless you intend to help test and develop a feature or driver that
37 falls into this category, or you have a situation that requires
38 using these features, you should probably say N here, which will
39 cause the configurator to present you with fewer choices. If
40 you say Y here, you will be offered the choice of using features or
41 drivers that are currently considered to be in the alpha-test phase.
48 depends on BROKEN || !SMP
53 depends on SMP || PREEMPT
56 config INIT_ENV_ARG_LIMIT
61 Maximum of each of the number of arguments and environment
62 variables passed to init from the kernel command line.
69 string "Local version - append to kernel release"
71 Append an extra string to the end of your kernel version.
72 This will show up when you type uname, for example.
73 The string you set here will be appended after the contents of
74 any files with a filename matching localversion* in your
75 object and source tree, in that order. Your total string can
76 be a maximum of 64 characters.
78 config LOCALVERSION_AUTO
79 bool "Automatically append version information to the version string"
82 This will try to automatically determine if the current tree is a
83 release tree by looking for git tags that
84 belong to the current top of tree revision.
86 A string of the format -gxxxxxxxx will be added to the localversion
87 if a git based tree is found. The string generated by this will be
88 appended after any matching localversion* files, and after the value
89 set in CONFIG_LOCALVERSION
91 Note: This requires Perl, and a git repository, but not necessarily
92 the git or cogito tools to be installed.
95 bool "Support for paging of anonymous memory (swap)"
96 depends on MMU && BLOCK
99 This option allows you to choose whether you want to have support
100 for so called swap devices or swap files in your kernel that are
101 used to provide more virtual memory than the actual RAM present
102 in your computer. If unsure say Y.
107 Inter Process Communication is a suite of library functions and
108 system calls which let processes (running programs) synchronize and
109 exchange information. It is generally considered to be a good thing,
110 and some programs won't run unless you say Y here. In particular, if
111 you want to run the DOS emulator dosemu under Linux (read the
112 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>),
113 you'll need to say Y here.
115 You can find documentation about IPC with "info ipc" and also in
116 section 6.4 of the Linux Programmer's Guide, available from
117 <http://www.tldp.org/guides.html>.
120 bool "IPC Namespaces"
124 Support ipc namespaces. This allows containers, i.e. virtual
125 environments, to use ipc namespaces to provide different ipc
126 objects for different servers. If unsure, say N.
129 bool "POSIX Message Queues"
130 depends on NET && EXPERIMENTAL
132 POSIX variant of message queues is a part of IPC. In POSIX message
133 queues every message has a priority which decides about succession
134 of receiving it by a process. If you want to compile and run
135 programs written e.g. for Solaris with use of its POSIX message
136 queues (functions mq_*) say Y here. To use this feature you will
137 also need mqueue library, available from
138 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/>
140 POSIX message queues are visible as a filesystem called 'mqueue'
141 and can be mounted somewhere if you want to do filesystem
142 operations on message queues.
146 config BSD_PROCESS_ACCT
147 bool "BSD Process Accounting"
149 If you say Y here, a user level program will be able to instruct the
150 kernel (via a special system call) to write process accounting
151 information to a file: whenever a process exits, information about
152 that process will be appended to the file by the kernel. The
153 information includes things such as creation time, owning user,
154 command name, memory usage, controlling terminal etc. (the complete
155 list is in the struct acct in <file:include/linux/acct.h>). It is
156 up to the user level program to do useful things with this
157 information. This is generally a good idea, so say Y.
159 config BSD_PROCESS_ACCT_V3
160 bool "BSD Process Accounting version 3 file format"
161 depends on BSD_PROCESS_ACCT
164 If you say Y here, the process accounting information is written
165 in a new file format that also logs the process IDs of each
166 process and it's parent. Note that this file format is incompatible
167 with previous v0/v1/v2 file formats, so you will need updated tools
168 for processing it. A preliminary version of these tools is available
169 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>.
172 bool "Export task/process statistics through netlink (EXPERIMENTAL)"
176 Export selected statistics for tasks/processes through the
177 generic netlink interface. Unlike BSD process accounting, the
178 statistics are available during the lifetime of tasks/processes as
179 responses to commands. Like BSD accounting, they are sent to user
184 config TASK_DELAY_ACCT
185 bool "Enable per-task delay accounting (EXPERIMENTAL)"
188 Collect information on time spent by a task waiting for system
189 resources like cpu, synchronous block I/O completion and swapping
190 in pages. Such statistics can help in setting a task's priorities
191 relative to other tasks for cpu, io, rss limits etc.
196 bool "UTS Namespaces"
199 Support uts namespaces. This allows containers, i.e.
200 vservers, to use uts namespaces to provide different
201 uts info for different servers. If unsure, say N.
204 bool "Auditing support"
207 Enable auditing infrastructure that can be used with another
208 kernel subsystem, such as SELinux (which requires this for
209 logging of avc messages output). Does not do system-call
210 auditing without CONFIG_AUDITSYSCALL.
213 bool "Enable system-call auditing support"
214 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64)
215 default y if SECURITY_SELINUX
217 Enable low-overhead system-call auditing infrastructure that
218 can be used independently or with another kernel subsystem,
219 such as SELinux. To use audit's filesystem watch feature, please
220 ensure that INOTIFY is configured.
223 tristate "Kernel .config support"
225 This option enables the complete Linux kernel ".config" file
226 contents to be saved in the kernel. It provides documentation
227 of which kernel options are used in a running kernel or in an
228 on-disk kernel. This information can be extracted from the kernel
229 image file with the script scripts/extract-ikconfig and used as
230 input to rebuild the current kernel or to build another kernel.
231 It can also be extracted from a running kernel by reading
232 /proc/config.gz if enabled (below).
235 bool "Enable access to .config through /proc/config.gz"
236 depends on IKCONFIG && PROC_FS
238 This option enables access to the kernel configuration file
239 through /proc/config.gz.
245 This option enables panic() to be called when a system is out of
246 memory. This feature along with /proc/sys/kernel/panic allows a
247 different behavior on out-of-memory conditions when the standard
248 behavior (killing processes in an attempt to recover) does not
255 depends on !OOM_PANIC
259 bool "Cpuset support"
262 This option will let you create and manage CPUSETs which
263 allow dynamically partitioning a system into sets of CPUs and
264 Memory Nodes and assigning tasks to run only within those sets.
265 This is primarily useful on large SMP or NUMA systems.
269 config SYSFS_DEPRECATED
270 bool "Create deprecated sysfs files"
273 This option creates deprecated symlinks such as the
274 "device"-link, the <subsystem>:<name>-link, and the
275 "bus"-link. It may also add deprecated key in the
277 None of these features or values should be used today, as
278 they export driver core implementation details to userspace
279 or export properties which can't be kept stable across kernel
282 If enabled, this option will also move any device structures
283 that belong to a class, back into the /sys/class heirachy, in
284 order to support older versions of udev.
286 If you are using a distro that was released in 2006 or later,
287 it should be safe to say N here.
290 bool "Kernel->user space relay support (formerly relayfs)"
292 This option enables support for relay interface support in
293 certain file systems (such as debugfs).
294 It is designed to provide an efficient mechanism for tools and
295 facilities to relay large amounts of data from kernel space to
302 config CC_OPTIMIZE_FOR_SIZE
303 bool "Optimize for size (Look out for broken compilers!)"
305 depends on ARM || H8300 || EXPERIMENTAL
307 Enabling this option will pass "-Os" instead of "-O2" to gcc
308 resulting in a smaller kernel.
310 WARNING: some versions of gcc may generate incorrect code with this
311 option. If problems are observed, a gcc upgrade may be needed.
316 bool "Enable extended accounting over taskstats (EXPERIMENTAL)"
319 Collect extended task accounting data and send the data
320 to userland for processing over the taskstats interface.
324 config TASK_IO_ACCOUNTING
325 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)"
326 depends on TASK_XACCT
328 Collect information on the number of bytes of storage I/O which this
337 bool "Configure standard kernel features (for small systems)"
339 This option allows certain base kernel options and settings
340 to be disabled or tweaked. This is for specialized
341 environments which can tolerate a "non-standard" kernel.
342 Only use this if you really know what you are doing.
345 bool "Enable 16-bit UID system calls" if EMBEDDED
346 depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION)
349 This enables the legacy 16-bit UID syscall wrappers.
351 config SYSCTL_SYSCALL
352 bool "Sysctl syscall support" if EMBEDDED
356 sys_sysctl uses binary paths that have been found challenging
357 to properly maintain and use. The interface in /proc/sys
358 using paths with ascii names is now the primary path to this
361 Almost nothing using the binary sysctl interface so if you are
362 trying to save some space it is probably safe to disable this,
363 making your kernel marginally smaller.
365 If unsure say Y here.
368 bool "Load all symbols for debugging/ksymoops" if EMBEDDED
371 Say Y here to let the kernel print out symbolic crash information and
372 symbolic stack backtraces. This increases the size of the kernel
373 somewhat, as all symbols have to be loaded into the kernel image.
376 bool "Include all symbols in kallsyms"
377 depends on DEBUG_KERNEL && KALLSYMS
379 Normally kallsyms only contains the symbols of functions, for nicer
380 OOPS messages. Some debuggers can use kallsyms for other
381 symbols too: say Y here to include all symbols, if you need them
382 and you don't care about adding 300k to the size of your kernel.
386 config KALLSYMS_EXTRA_PASS
387 bool "Do an extra kallsyms pass"
390 If kallsyms is not working correctly, the build will fail with
391 inconsistent kallsyms data. If that occurs, log a bug report and
392 turn on KALLSYMS_EXTRA_PASS which should result in a stable build.
393 Always say N here unless you find a bug in kallsyms, which must be
394 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
395 you wait for kallsyms to be fixed.
399 bool "Support for hot-pluggable devices" if EMBEDDED
402 This option is provided for the case where no hotplug or uevent
403 capabilities is wanted by the kernel. You should only consider
404 disabling this option for embedded systems that do not use modules, a
405 dynamic /dev tree, or dynamic device discovery. Just say Y.
409 bool "Enable support for printk" if EMBEDDED
411 This option enables normal printk support. Removing it
412 eliminates most of the message strings from the kernel image
413 and makes the kernel more or less silent. As this makes it
414 very difficult to diagnose system problems, saying N here is
415 strongly discouraged.
418 bool "BUG() support" if EMBEDDED
421 Disabling this option eliminates support for BUG and WARN, reducing
422 the size of your kernel image and potentially quietly ignoring
423 numerous fatal conditions. You should only consider disabling this
424 option for embedded systems with no facilities for reporting errors.
429 bool "Enable ELF core dumps" if EMBEDDED
431 Enable support for generating core dumps. Disabling saves about 4k.
435 bool "Enable full-sized data structures for core" if EMBEDDED
437 Disabling this option reduces the size of miscellaneous core
438 kernel data structures. This saves memory on small machines,
439 but may reduce performance.
442 bool "Enable futex support" if EMBEDDED
446 Disabling this option will cause the kernel to be built without
447 support for "fast userspace mutexes". The resulting kernel may not
448 run glibc-based applications correctly.
451 bool "Enable eventpoll support" if EMBEDDED
454 Disabling this option will cause the kernel to be built without
455 support for epoll family of system calls.
458 bool "Use full shmem filesystem" if EMBEDDED
462 The shmem is an internal filesystem used to manage shared memory.
463 It is backed by swap and manages resource limits. It is also exported
464 to userspace as tmpfs if TMPFS is enabled. Disabling this
465 option replaces shmem and tmpfs with the much simpler ramfs code,
466 which may be appropriate on small systems without swap.
470 bool "Use full SLAB allocator" if (EMBEDDED && !SMP && !SPARSEMEM)
472 Disabling this replaces the advanced SLAB allocator and
473 kmalloc support with the drastically simpler SLOB allocator.
474 SLOB is more space efficient but does not scale well and is
475 more susceptible to fragmentation.
477 config VM_EVENT_COUNTERS
479 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
481 VM event counters are needed for event counts to be shown.
482 This option allows the disabling of the VM event counters
483 on EMBEDDED systems. /proc/vmstat will only show page counts
484 if VM event counters are disabled.
486 endmenu # General setup
498 default 0 if BASE_FULL
499 default 1 if !BASE_FULL
505 menu "Loadable module support"
508 bool "Enable loadable module support"
510 Kernel modules are small pieces of compiled code which can
511 be inserted in the running kernel, rather than being
512 permanently built into the kernel. You use the "modprobe"
513 tool to add (and sometimes remove) them. If you say Y here,
514 many parts of the kernel can be built as modules (by
515 answering M instead of Y where indicated): this is most
516 useful for infrequently used options which are not required
517 for booting. For more information, see the man pages for
518 modprobe, lsmod, modinfo, insmod and rmmod.
520 If you say Y here, you will need to run "make
521 modules_install" to put the modules under /lib/modules/
522 where modprobe can find them (you may need to be root to do
528 bool "Module unloading"
531 Without this option you will not be able to unload any
532 modules (note that some modules may not be unloadable
533 anyway), which makes your kernel slightly smaller and
534 simpler. If unsure, say Y.
536 config MODULE_FORCE_UNLOAD
537 bool "Forced module unloading"
538 depends on MODULE_UNLOAD && EXPERIMENTAL
540 This option allows you to force a module to unload, even if the
541 kernel believes it is unsafe: the kernel will remove the module
542 without waiting for anyone to stop using it (using the -f option to
543 rmmod). This is mainly for kernel developers and desperate users.
547 bool "Module versioning support"
550 Usually, you have to use modules compiled with your kernel.
551 Saying Y here makes it sometimes possible to use modules
552 compiled for different kernels, by adding enough information
553 to the modules to (hopefully) spot any changes which would
554 make them incompatible with the kernel you are running. If
557 config MODULE_SRCVERSION_ALL
558 bool "Source checksum for all modules"
561 Modules which contain a MODULE_VERSION get an extra "srcversion"
562 field inserted into their modinfo section, which contains a
563 sum of the source files which made it. This helps maintainers
564 see exactly which source was used to build a module (since
565 others sometimes change the module source without updating
566 the version). With this option, such a "srcversion" field
567 will be created for all modules. If unsure, say N.
569 config MODULE_VERIFY_ELF
570 bool "Module ELF structure verification"
573 Check ELF structure of modules upon load
576 bool "Module signature verification (EXPERIMENTAL)"
577 depends on MODULES && EXPERIMENTAL
580 select CRYPTO_SIGNATURE
582 Check modules for valid signatures upon load.
584 config MODULE_SIG_FORCE
585 bool "Required modules to be validly signed (EXPERIMENTAL)"
586 depends on MODULE_SIG
588 Reject unsigned modules or signed modules for which we don't have a
594 default y if MODULE_VERIFY_ELF || MODULE_SIG
597 bool "Automatic kernel module loading"
600 Normally when you have selected some parts of the kernel to
601 be created as kernel modules, you must load them (using the
602 "modprobe" command) before you can use them. If you say Y
603 here, some parts of the kernel will be able to load modules
604 automatically: when a part of the kernel needs a module, it
605 runs modprobe with the appropriate arguments, thereby
606 loading the module if it is available. If unsure, say Y.
611 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU
613 Need stop_machine() primitive.
616 menu "Process debugging support"
619 bool "Infrastructure for tracing and debugging user processes"
622 Enable the utrace process tracing interface.
623 This is an internal kernel interface to track events in user
624 threads, extract and change user thread state. This interface
625 is exported to kernel modules, and is also used to implement ptrace.
626 If you disable this, no facilities for debugging user processes
627 will be available, nor the facilities used by UML and other
628 applications. Unless you are making a specially stripped-down
629 kernel and are very sure you don't need these facilitiies,
633 bool "Legacy ptrace system call interface"
637 Enable the ptrace system call.
638 This is traditionally used by debuggers like GDB,
639 and is used by UML and some other applications.
640 Unless you are very sure you won't run anything that needs it,
646 source "block/Kconfig"