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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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