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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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. 186 187config IKCONFIG 188 bool "Kernel .config support" 189 ---help--- 190 This option enables the complete Linux kernel ".config" file 191 contents to be saved in the kernel. It provides documentation 192 of which kernel options are used in a running kernel or in an 193 on-disk kernel. This information can be extracted from the kernel 194 image file with the script scripts/extract-ikconfig and used as 195 input to rebuild the current kernel or to build another kernel. 196 It can also be extracted from a running kernel by reading 197 /proc/config.gz if enabled (below). 198 199config IKCONFIG_PROC 200 bool "Enable access to .config through /proc/config.gz" 201 depends on IKCONFIG && PROC_FS 202 ---help--- 203 This option enables access to the kernel configuration file 204 through /proc/config.gz. 205 206config CPUSETS 207 bool "Cpuset support" 208 depends on SMP 209 help 210 This option will let you create and manage CPUSETs which 211 allow dynamically partitioning a system into sets of CPUs and 212 Memory Nodes and assigning tasks to run only within those sets. 213 This is primarily useful on large SMP or NUMA systems. 214 215 Say N if unsure. 216 217source "usr/Kconfig" 218 219config UID16 220 bool "Enable 16-bit UID system calls" if EMBEDDED 221 depends on ARM || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 222 default y 223 help 224 This enables the legacy 16-bit UID syscall wrappers. 225 226config VM86 227 depends X86 228 default y 229 bool "Enable VM86 support" if EMBEDDED 230 help 231 This option is required by programs like DOSEMU to run 16-bit legacy 232 code on X86 processors. It also may be needed by software like 233 XFree86 to initialize some video cards via BIOS. Disabling this 234 option saves about 6k. 235 236config CC_OPTIMIZE_FOR_SIZE 237 bool "Optimize for size (Look out for broken compilers!)" 238 default y 239 depends on ARM || H8300 || EXPERIMENTAL 240 help 241 Enabling this option will pass "-Os" instead of "-O2" to gcc 242 resulting in a smaller kernel. 243 244 WARNING: some versions of gcc may generate incorrect code with this 245 option. If problems are observed, a gcc upgrade may be needed. 246 247 If unsure, say N. 248 249menuconfig EMBEDDED 250 bool "Configure standard kernel features (for small systems)" 251 help 252 This option allows certain base kernel options and settings 253 to be disabled or tweaked. This is for specialized 254 environments which can tolerate a "non-standard" kernel. 255 Only use this if you really know what you are doing. 256 257config KALLSYMS 258 bool "Load all symbols for debugging/kksymoops" if EMBEDDED 259 default y 260 help 261 Say Y here to let the kernel print out symbolic crash information and 262 symbolic stack backtraces. This increases the size of the kernel 263 somewhat, as all symbols have to be loaded into the kernel image. 264 265config KALLSYMS_ALL 266 bool "Include all symbols in kallsyms" 267 depends on DEBUG_KERNEL && KALLSYMS 268 help 269 Normally kallsyms only contains the symbols of functions, for nicer 270 OOPS messages. Some debuggers can use kallsyms for other 271 symbols too: say Y here to include all symbols, if you need them 272 and you don't care about adding 300k to the size of your kernel. 273 274 Say N. 275 276config KALLSYMS_EXTRA_PASS 277 bool "Do an extra kallsyms pass" 278 depends on KALLSYMS 279 help 280 If kallsyms is not working correctly, the build will fail with 281 inconsistent kallsyms data. If that occurs, log a bug report and 282 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 283 Always say N here unless you find a bug in kallsyms, which must be 284 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 285 you wait for kallsyms to be fixed. 286 287 288config HOTPLUG 289 bool "Support for hot-pluggable devices" if EMBEDDED 290 default y 291 help 292 This option is provided for the case where no hotplug or uevent 293 capabilities is wanted by the kernel. You should only consider 294 disabling this option for embedded systems that do not use modules, a 295 dynamic /dev tree, or dynamic device discovery. Just say Y. 296 297config PRINTK 298 default y 299 bool "Enable support for printk" if EMBEDDED 300 help 301 This option enables normal printk support. Removing it 302 eliminates most of the message strings from the kernel image 303 and makes the kernel more or less silent. As this makes it 304 very difficult to diagnose system problems, saying N here is 305 strongly discouraged. 306 307config BUG 308 bool "BUG() support" if EMBEDDED 309 default y 310 help 311 Disabling this option eliminates support for BUG and WARN, reducing 312 the size of your kernel image and potentially quietly ignoring 313 numerous fatal conditions. You should only consider disabling this 314 option for embedded systems with no facilities for reporting errors. 315 Just say Y. 316 317config ELF_CORE 318 default y 319 bool "Enable ELF core dumps" if EMBEDDED 320 help 321 Enable support for generating core dumps. Disabling saves about 4k. 322 323config BASE_FULL 324 default y 325 bool "Enable full-sized data structures for core" if EMBEDDED 326 help 327 Disabling this option reduces the size of miscellaneous core 328 kernel data structures. This saves memory on small machines, 329 but may reduce performance. 330 331config FUTEX 332 bool "Enable futex support" if EMBEDDED 333 default y 334 help 335 Disabling this option will cause the kernel to be built without 336 support for "fast userspace mutexes". The resulting kernel may not 337 run glibc-based applications correctly. 338 339config EPOLL 340 bool "Enable eventpoll support" if EMBEDDED 341 default y 342 help 343 Disabling this option will cause the kernel to be built without 344 support for epoll family of system calls. 345 346config SHMEM 347 bool "Use full shmem filesystem" if EMBEDDED 348 default y 349 depends on MMU 350 help 351 The shmem is an internal filesystem used to manage shared memory. 352 It is backed by swap and manages resource limits. It is also exported 353 to userspace as tmpfs if TMPFS is enabled. Disabling this 354 option replaces shmem and tmpfs with the much simpler ramfs code, 355 which may be appropriate on small systems without swap. 356 357config CC_ALIGN_FUNCTIONS 358 int "Function alignment" if EMBEDDED 359 default 0 360 help 361 Align the start of functions to the next power-of-two greater than n, 362 skipping up to n bytes. For instance, 32 aligns functions 363 to the next 32-byte boundary, but 24 would align to the next 364 32-byte boundary only if this can be done by skipping 23 bytes or less. 365 Zero means use compiler's default. 366 367config CC_ALIGN_LABELS 368 int "Label alignment" if EMBEDDED 369 default 0 370 help 371 Align all branch targets to a power-of-two boundary, skipping 372 up to n bytes like ALIGN_FUNCTIONS. This option can easily 373 make code slower, because it must insert dummy operations for 374 when the branch target is reached in the usual flow of the code. 375 Zero means use compiler's default. 376 377config CC_ALIGN_LOOPS 378 int "Loop alignment" if EMBEDDED 379 default 0 380 help 381 Align loops to a power-of-two boundary, skipping up to n bytes. 382 Zero means use compiler's default. 383 384config CC_ALIGN_JUMPS 385 int "Jump alignment" if EMBEDDED 386 default 0 387 help 388 Align branch targets to a power-of-two boundary, for branch 389 targets where the targets can only be reached by jumping, 390 skipping up to n bytes like ALIGN_FUNCTIONS. In this case, 391 no dummy operations need be executed. 392 Zero means use compiler's default. 393 394config SLAB 395 default y 396 bool "Use full SLAB allocator" if EMBEDDED 397 help 398 Disabling this replaces the advanced SLAB allocator and 399 kmalloc support with the drastically simpler SLOB allocator. 400 SLOB is more space efficient but does not scale well and is 401 more susceptible to fragmentation. 402 403endmenu # General setup 404 405config TINY_SHMEM 406 default !SHMEM 407 bool 408 409config BASE_SMALL 410 int 411 default 0 if BASE_FULL 412 default 1 if !BASE_FULL 413 414config SLOB 415 default !SLAB 416 bool 417 418config OBSOLETE_INTERMODULE 419 tristate 420 421menu "Loadable module support" 422 423config MODULES 424 bool "Enable loadable module support" 425 help 426 Kernel modules are small pieces of compiled code which can 427 be inserted in the running kernel, rather than being 428 permanently built into the kernel. You use the "modprobe" 429 tool to add (and sometimes remove) them. If you say Y here, 430 many parts of the kernel can be built as modules (by 431 answering M instead of Y where indicated): this is most 432 useful for infrequently used options which are not required 433 for booting. For more information, see the man pages for 434 modprobe, lsmod, modinfo, insmod and rmmod. 435 436 If you say Y here, you will need to run "make 437 modules_install" to put the modules under /lib/modules/ 438 where modprobe can find them (you may need to be root to do 439 this). 440 441 If unsure, say Y. 442 443config MODULE_UNLOAD 444 bool "Module unloading" 445 depends on MODULES 446 help 447 Without this option you will not be able to unload any 448 modules (note that some modules may not be unloadable 449 anyway), which makes your kernel slightly smaller and 450 simpler. If unsure, say Y. 451 452config MODULE_FORCE_UNLOAD 453 bool "Forced module unloading" 454 depends on MODULE_UNLOAD && EXPERIMENTAL 455 help 456 This option allows you to force a module to unload, even if the 457 kernel believes it is unsafe: the kernel will remove the module 458 without waiting for anyone to stop using it (using the -f option to 459 rmmod). This is mainly for kernel developers and desperate users. 460 If unsure, say N. 461 462config OBSOLETE_MODPARM 463 bool 464 default y 465 depends on MODULES 466 help 467 You need this option to use module parameters on modules which 468 have not been converted to the new module parameter system yet. 469 If unsure, say Y. 470 471config MODVERSIONS 472 bool "Module versioning support" 473 depends on MODULES 474 help 475 Usually, you have to use modules compiled with your kernel. 476 Saying Y here makes it sometimes possible to use modules 477 compiled for different kernels, by adding enough information 478 to the modules to (hopefully) spot any changes which would 479 make them incompatible with the kernel you are running. If 480 unsure, say N. 481 482config MODULE_SRCVERSION_ALL 483 bool "Source checksum for all modules" 484 depends on MODULES 485 help 486 Modules which contain a MODULE_VERSION get an extra "srcversion" 487 field inserted into their modinfo section, which contains a 488 sum of the source files which made it. This helps maintainers 489 see exactly which source was used to build a module (since 490 others sometimes change the module source without updating 491 the version). With this option, such a "srcversion" field 492 will be created for all modules. If unsure, say N. 493 494config KMOD 495 bool "Automatic kernel module loading" 496 depends on MODULES 497 help 498 Normally when you have selected some parts of the kernel to 499 be created as kernel modules, you must load them (using the 500 "modprobe" command) before you can use them. If you say Y 501 here, some parts of the kernel will be able to load modules 502 automatically: when a part of the kernel needs a module, it 503 runs modprobe with the appropriate arguments, thereby 504 loading the module if it is available. If unsure, say Y. 505 506config STOP_MACHINE 507 bool 508 default y 509 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 510 help 511 Need stop_machine() primitive. 512endmenu 513 514menu "Block layer" 515source "block/Kconfig" 516endmenu 517