1menu "Code maturity level options" 2 3config EXPERIMENTAL 4 bool "Prompt for development and/or incomplete code/drivers" 5 ---help--- 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). 22 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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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. 33 34config BROKEN 35 bool 36 37config BROKEN_ON_SMP 38 bool 39 depends on BROKEN || !SMP 40 default y 41 42config LOCK_KERNEL 43 bool 44 depends on SMP || PREEMPT 45 default y 46 47config INIT_ENV_ARG_LIMIT 48 int 49 default 32 if !USERMODE 50 default 128 if USERMODE 51 help 52 Maximum of each of the number of arguments and environment 53 variables passed to init from the kernel command line. 54 55endmenu 56 57menu "General setup" 58 59config LOCALVERSION 60 string "Local version - append to kernel release" 61 help 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. 68 69config LOCALVERSION_AUTO 70 bool "Automatically append version information to the version string" 71 default y 72 help 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. 76 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 81 82 Note: This requires Perl, and a git repository, but not necessarily 83 the git or cogito tools to be installed. 84 85config SWAP 86 bool "Support for paging of anonymous memory (swap)" 87 depends on MMU 88 default y 89 help 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. 94 95config SYSVIPC 96 bool "System V IPC" 97 ---help--- 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. 105 106 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>. 109 110config POSIX_MQUEUE 111 bool "POSIX Message Queues" 112 depends on NET && EXPERIMENTAL 113 ---help--- 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/> 121 122 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. 125 126 If unsure, say Y. 127 128config BSD_PROCESS_ACCT 129 bool "BSD Process Accounting" 130 help 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. 140 141config BSD_PROCESS_ACCT_V3 142 bool "BSD Process Accounting version 3 file format" 143 depends on BSD_PROCESS_ACCT 144 default n 145 help 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/>. 152 153config SYSCTL 154 bool "Sysctl support" 155 ---help--- 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. 164 165 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 167 limited in memory. 168 169config AUDIT 170 bool "Auditing support" 171 depends on NET 172 help 173 Enable auditing infrastructure that can be used with another 174 kernel subsystem, such as SELinux (which requires this for 175 logging of avc messages output). Does not do system-call 176 auditing without CONFIG_AUDITSYSCALL. 177 178config AUDITSYSCALL 179 bool "Enable system-call auditing support" 180 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64) 181 default y if SECURITY_SELINUX 182 help 183 Enable low-overhead system-call auditing infrastructure that 184 can be used independently or with another kernel subsystem, 185 such as SELinux. To use audit's filesystem watch feature, please 186 ensure that INOTIFY is configured. 187 188config IKCONFIG 189 bool "Kernel .config support" 190 ---help--- 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). 199 200config IKCONFIG_PROC 201 bool "Enable access to .config through /proc/config.gz" 202 depends on IKCONFIG && PROC_FS 203 ---help--- 204 This option enables access to the kernel configuration file 205 through /proc/config.gz. 206 207config CPUSETS 208 bool "Cpuset support" 209 depends on SMP 210 help 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. 215 216 Say N if unsure. 217 218config RELAY 219 bool "Kernel->user space relay support (formerly relayfs)" 220 help 221 This option enables support for relay interface support in 222 certain file systems (such as debugfs). 223 It is designed to provide an efficient mechanism for tools and 224 facilities to relay large amounts of data from kernel space to 225 user space. 226 227 If unsure, say N. 228 229source "usr/Kconfig" 230 231config UID16 232 bool "Enable 16-bit UID system calls" if EMBEDDED 233 depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 234 default y 235 help 236 This enables the legacy 16-bit UID syscall wrappers. 237 238config VM86 239 depends X86 240 default y 241 bool "Enable VM86 support" if EMBEDDED 242 help 243 This option is required by programs like DOSEMU to run 16-bit legacy 244 code on X86 processors. It also may be needed by software like 245 XFree86 to initialize some video cards via BIOS. Disabling this 246 option saves about 6k. 247 248config CC_OPTIMIZE_FOR_SIZE 249 bool "Optimize for size (Look out for broken compilers!)" 250 default y 251 depends on ARM || H8300 || EXPERIMENTAL 252 help 253 Enabling this option will pass "-Os" instead of "-O2" to gcc 254 resulting in a smaller kernel. 255 256 WARNING: some versions of gcc may generate incorrect code with this 257 option. If problems are observed, a gcc upgrade may be needed. 258 259 If unsure, say N. 260 261menuconfig EMBEDDED 262 bool "Configure standard kernel features (for small systems)" 263 help 264 This option allows certain base kernel options and settings 265 to be disabled or tweaked. This is for specialized 266 environments which can tolerate a "non-standard" kernel. 267 Only use this if you really know what you are doing. 268 269config KALLSYMS 270 bool "Load all symbols for debugging/kksymoops" if EMBEDDED 271 default y 272 help 273 Say Y here to let the kernel print out symbolic crash information and 274 symbolic stack backtraces. This increases the size of the kernel 275 somewhat, as all symbols have to be loaded into the kernel image. 276 277config KALLSYMS_ALL 278 bool "Include all symbols in kallsyms" 279 depends on DEBUG_KERNEL && KALLSYMS 280 help 281 Normally kallsyms only contains the symbols of functions, for nicer 282 OOPS messages. Some debuggers can use kallsyms for other 283 symbols too: say Y here to include all symbols, if you need them 284 and you don't care about adding 300k to the size of your kernel. 285 286 Say N. 287 288config KALLSYMS_EXTRA_PASS 289 bool "Do an extra kallsyms pass" 290 depends on KALLSYMS 291 help 292 If kallsyms is not working correctly, the build will fail with 293 inconsistent kallsyms data. If that occurs, log a bug report and 294 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 295 Always say N here unless you find a bug in kallsyms, which must be 296 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 297 you wait for kallsyms to be fixed. 298 299 300config HOTPLUG 301 bool "Support for hot-pluggable devices" if EMBEDDED 302 default y 303 help 304 This option is provided for the case where no hotplug or uevent 305 capabilities is wanted by the kernel. You should only consider 306 disabling this option for embedded systems that do not use modules, a 307 dynamic /dev tree, or dynamic device discovery. Just say Y. 308 309config PRINTK 310 default y 311 bool "Enable support for printk" if EMBEDDED 312 help 313 This option enables normal printk support. Removing it 314 eliminates most of the message strings from the kernel image 315 and makes the kernel more or less silent. As this makes it 316 very difficult to diagnose system problems, saying N here is 317 strongly discouraged. 318 319config BUG 320 bool "BUG() support" if EMBEDDED 321 default y 322 help 323 Disabling this option eliminates support for BUG and WARN, reducing 324 the size of your kernel image and potentially quietly ignoring 325 numerous fatal conditions. You should only consider disabling this 326 option for embedded systems with no facilities for reporting errors. 327 Just say Y. 328 329config ELF_CORE 330 default y 331 bool "Enable ELF core dumps" if EMBEDDED 332 help 333 Enable support for generating core dumps. Disabling saves about 4k. 334 335config BASE_FULL 336 default y 337 bool "Enable full-sized data structures for core" if EMBEDDED 338 help 339 Disabling this option reduces the size of miscellaneous core 340 kernel data structures. This saves memory on small machines, 341 but may reduce performance. 342 343config FUTEX 344 bool "Enable futex support" if EMBEDDED 345 default y 346 help 347 Disabling this option will cause the kernel to be built without 348 support for "fast userspace mutexes". The resulting kernel may not 349 run glibc-based applications correctly. 350 351config EPOLL 352 bool "Enable eventpoll support" if EMBEDDED 353 default y 354 help 355 Disabling this option will cause the kernel to be built without 356 support for epoll family of system calls. 357 358config SHMEM 359 bool "Use full shmem filesystem" if EMBEDDED 360 default y 361 depends on MMU 362 help 363 The shmem is an internal filesystem used to manage shared memory. 364 It is backed by swap and manages resource limits. It is also exported 365 to userspace as tmpfs if TMPFS is enabled. Disabling this 366 option replaces shmem and tmpfs with the much simpler ramfs code, 367 which may be appropriate on small systems without swap. 368 369config SLAB 370 default y 371 bool "Use full SLAB allocator" if EMBEDDED 372 help 373 Disabling this replaces the advanced SLAB allocator and 374 kmalloc support with the drastically simpler SLOB allocator. 375 SLOB is more space efficient but does not scale well and is 376 more susceptible to fragmentation. 377 378endmenu # General setup 379 380config TINY_SHMEM 381 default !SHMEM 382 bool 383 384config BASE_SMALL 385 int 386 default 0 if BASE_FULL 387 default 1 if !BASE_FULL 388 389config SLOB 390 default !SLAB 391 bool 392 393menu "Loadable module support" 394 395config MODULES 396 bool "Enable loadable module support" 397 help 398 Kernel modules are small pieces of compiled code which can 399 be inserted in the running kernel, rather than being 400 permanently built into the kernel. You use the "modprobe" 401 tool to add (and sometimes remove) them. If you say Y here, 402 many parts of the kernel can be built as modules (by 403 answering M instead of Y where indicated): this is most 404 useful for infrequently used options which are not required 405 for booting. For more information, see the man pages for 406 modprobe, lsmod, modinfo, insmod and rmmod. 407 408 If you say Y here, you will need to run "make 409 modules_install" to put the modules under /lib/modules/ 410 where modprobe can find them (you may need to be root to do 411 this). 412 413 If unsure, say Y. 414 415config MODULE_UNLOAD 416 bool "Module unloading" 417 depends on MODULES 418 help 419 Without this option you will not be able to unload any 420 modules (note that some modules may not be unloadable 421 anyway), which makes your kernel slightly smaller and 422 simpler. If unsure, say Y. 423 424config MODULE_FORCE_UNLOAD 425 bool "Forced module unloading" 426 depends on MODULE_UNLOAD && EXPERIMENTAL 427 help 428 This option allows you to force a module to unload, even if the 429 kernel believes it is unsafe: the kernel will remove the module 430 without waiting for anyone to stop using it (using the -f option to 431 rmmod). This is mainly for kernel developers and desperate users. 432 If unsure, say N. 433 434config MODVERSIONS 435 bool "Module versioning support" 436 depends on MODULES 437 help 438 Usually, you have to use modules compiled with your kernel. 439 Saying Y here makes it sometimes possible to use modules 440 compiled for different kernels, by adding enough information 441 to the modules to (hopefully) spot any changes which would 442 make them incompatible with the kernel you are running. If 443 unsure, say N. 444 445config MODULE_SRCVERSION_ALL 446 bool "Source checksum for all modules" 447 depends on MODULES 448 help 449 Modules which contain a MODULE_VERSION get an extra "srcversion" 450 field inserted into their modinfo section, which contains a 451 sum of the source files which made it. This helps maintainers 452 see exactly which source was used to build a module (since 453 others sometimes change the module source without updating 454 the version). With this option, such a "srcversion" field 455 will be created for all modules. If unsure, say N. 456 457config KMOD 458 bool "Automatic kernel module loading" 459 depends on MODULES 460 help 461 Normally when you have selected some parts of the kernel to 462 be created as kernel modules, you must load them (using the 463 "modprobe" command) before you can use them. If you say Y 464 here, some parts of the kernel will be able to load modules 465 automatically: when a part of the kernel needs a module, it 466 runs modprobe with the appropriate arguments, thereby 467 loading the module if it is available. If unsure, say Y. 468 469config STOP_MACHINE 470 bool 471 default y 472 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 473 help 474 Need stop_machine() primitive. 475endmenu 476 477menu "Block layer" 478source "block/Kconfig" 479endmenu 480