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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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 default y if SECURITY_SELINUX 173 help 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. 178 179config 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 183 help 184 Enable low-overhead system-call auditing infrastructure that 185 can be used independently or with another kernel subsystem, 186 such as SELinux. 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 218source "usr/Kconfig" 219 220config UID16 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) 223 default y 224 help 225 This enables the legacy 16-bit UID syscall wrappers. 226 227config VM86 228 depends X86 229 default y 230 bool "Enable VM86 support" if EMBEDDED 231 help 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. 236 237config CC_OPTIMIZE_FOR_SIZE 238 bool "Optimize for size (Look out for broken compilers!)" 239 default y 240 depends on ARM || H8300 || EXPERIMENTAL 241 help 242 Enabling this option will pass "-Os" instead of "-O2" to gcc 243 resulting in a smaller kernel. 244 245 WARNING: some versions of gcc may generate incorrect code with this 246 option. If problems are observed, a gcc upgrade may be needed. 247 248 If unsure, say N. 249 250menuconfig EMBEDDED 251 bool "Configure standard kernel features (for small systems)" 252 help 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. 257 258config KALLSYMS 259 bool "Load all symbols for debugging/kksymoops" if EMBEDDED 260 default y 261 help 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. 265 266config KALLSYMS_ALL 267 bool "Include all symbols in kallsyms" 268 depends on DEBUG_KERNEL && KALLSYMS 269 help 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. 274 275 Say N. 276 277config KALLSYMS_EXTRA_PASS 278 bool "Do an extra kallsyms pass" 279 depends on KALLSYMS 280 help 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. 287 288 289config HOTPLUG 290 bool "Support for hot-pluggable devices" if EMBEDDED 291 default y 292 help 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. 297 298config PRINTK 299 default y 300 bool "Enable support for printk" if EMBEDDED 301 help 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. 307 308config BUG 309 bool "BUG() support" if EMBEDDED 310 default y 311 help 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. 316 Just say Y. 317 318config ELF_CORE 319 default y 320 bool "Enable ELF core dumps" if EMBEDDED 321 help 322 Enable support for generating core dumps. Disabling saves about 4k. 323 324config BASE_FULL 325 default y 326 bool "Enable full-sized data structures for core" if EMBEDDED 327 help 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. 331 332config FUTEX 333 bool "Enable futex support" if EMBEDDED 334 default y 335 help 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. 339 340config EPOLL 341 bool "Enable eventpoll support" if EMBEDDED 342 default y 343 help 344 Disabling this option will cause the kernel to be built without 345 support for epoll family of system calls. 346 347config SHMEM 348 bool "Use full shmem filesystem" if EMBEDDED 349 default y 350 depends on MMU 351 help 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. 357 358config CC_ALIGN_FUNCTIONS 359 int "Function alignment" if EMBEDDED 360 default 0 361 help 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. 367 368config CC_ALIGN_LABELS 369 int "Label alignment" if EMBEDDED 370 default 0 371 help 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. 377 378config CC_ALIGN_LOOPS 379 int "Loop alignment" if EMBEDDED 380 default 0 381 help 382 Align loops to a power-of-two boundary, skipping up to n bytes. 383 Zero means use compiler's default. 384 385config CC_ALIGN_JUMPS 386 int "Jump alignment" if EMBEDDED 387 default 0 388 help 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. 394 395config SLAB 396 default y 397 bool "Use full SLAB allocator" if EMBEDDED 398 help 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. 403 404endmenu # General setup 405 406config TINY_SHMEM 407 default !SHMEM 408 bool 409 410config BASE_SMALL 411 int 412 default 0 if BASE_FULL 413 default 1 if !BASE_FULL 414 415config SLOB 416 default !SLAB 417 bool 418 419config OBSOLETE_INTERMODULE 420 tristate 421 422menu "Loadable module support" 423 424config MODULES 425 bool "Enable loadable module support" 426 help 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. 436 437 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 440 this). 441 442 If unsure, say Y. 443 444config MODULE_UNLOAD 445 bool "Module unloading" 446 depends on MODULES 447 help 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. 452 453config MODULE_FORCE_UNLOAD 454 bool "Forced module unloading" 455 depends on MODULE_UNLOAD && EXPERIMENTAL 456 help 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. 461 If unsure, say N. 462 463config OBSOLETE_MODPARM 464 bool 465 default y 466 depends on MODULES 467 help 468 You need this option to use module parameters on modules which 469 have not been converted to the new module parameter system yet. 470 If unsure, say Y. 471 472config MODVERSIONS 473 bool "Module versioning support" 474 depends on MODULES 475 help 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 481 unsure, say N. 482 483config MODULE_SRCVERSION_ALL 484 bool "Source checksum for all modules" 485 depends on MODULES 486 help 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. 494 495config KMOD 496 bool "Automatic kernel module loading" 497 depends on MODULES 498 help 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. 506 507config STOP_MACHINE 508 bool 509 default y 510 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 511 help 512 Need stop_machine() primitive. 513endmenu 514 515menu "Block layer" 516source "block/Kconfig" 517endmenu 518