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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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 CLEAN_COMPILE 35 bool "Select only drivers expected to compile cleanly" if EXPERIMENTAL 36 default y 37 help 38 Select this option if you don't even want to see the option 39 to configure known-broken drivers. 40 41 If unsure, say Y 42 43config BROKEN 44 bool 45 depends on !CLEAN_COMPILE 46 default y 47 48config BROKEN_ON_SMP 49 bool 50 depends on BROKEN || !SMP 51 default y 52 53config LOCK_KERNEL 54 bool 55 depends on SMP || PREEMPT 56 default y 57 58config INIT_ENV_ARG_LIMIT 59 int 60 default 32 if !USERMODE 61 default 128 if USERMODE 62 help 63 Maximum of each of the number of arguments and environment 64 variables passed to init from the kernel command line. 65 66endmenu 67 68menu "General setup" 69 70config LOCALVERSION 71 string "Local version - append to kernel release" 72 help 73 Append an extra string to the end of your kernel version. 74 This will show up when you type uname, for example. 75 The string you set here will be appended after the contents of 76 any files with a filename matching localversion* in your 77 object and source tree, in that order. Your total string can 78 be a maximum of 64 characters. 79 80config LOCALVERSION_AUTO 81 bool "Automatically append version information to the version string" 82 default y 83 help 84 This will try to automatically determine if the current tree is a 85 release tree by looking for git tags that 86 belong to the current top of tree revision. 87 88 A string of the format -gxxxxxxxx will be added to the localversion 89 if a git based tree is found. The string generated by this will be 90 appended after any matching localversion* files, and after the value 91 set in CONFIG_LOCALVERSION 92 93 Note: This requires Perl, and a git repository, but not necessarily 94 the git or cogito tools to be installed. 95 96config SWAP 97 bool "Support for paging of anonymous memory (swap)" 98 depends on MMU 99 default y 100 help 101 This option allows you to choose whether you want to have support 102 for socalled swap devices or swap files in your kernel that are 103 used to provide more virtual memory than the actual RAM present 104 in your computer. If unsure say Y. 105 106config SYSVIPC 107 bool "System V IPC" 108 depends on MMU 109 ---help--- 110 Inter Process Communication is a suite of library functions and 111 system calls which let processes (running programs) synchronize and 112 exchange information. It is generally considered to be a good thing, 113 and some programs won't run unless you say Y here. In particular, if 114 you want to run the DOS emulator dosemu under Linux (read the 115 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 116 you'll need to say Y here. 117 118 You can find documentation about IPC with "info ipc" and also in 119 section 6.4 of the Linux Programmer's Guide, available from 120 <http://www.tldp.org/guides.html>. 121 122config POSIX_MQUEUE 123 bool "POSIX Message Queues" 124 depends on NET && EXPERIMENTAL 125 ---help--- 126 POSIX variant of message queues is a part of IPC. In POSIX message 127 queues every message has a priority which decides about succession 128 of receiving it by a process. If you want to compile and run 129 programs written e.g. for Solaris with use of its POSIX message 130 queues (functions mq_*) say Y here. To use this feature you will 131 also need mqueue library, available from 132 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/> 133 134 POSIX message queues are visible as a filesystem called 'mqueue' 135 and can be mounted somewhere if you want to do filesystem 136 operations on message queues. 137 138 If unsure, say Y. 139 140config BSD_PROCESS_ACCT 141 bool "BSD Process Accounting" 142 help 143 If you say Y here, a user level program will be able to instruct the 144 kernel (via a special system call) to write process accounting 145 information to a file: whenever a process exits, information about 146 that process will be appended to the file by the kernel. The 147 information includes things such as creation time, owning user, 148 command name, memory usage, controlling terminal etc. (the complete 149 list is in the struct acct in <file:include/linux/acct.h>). It is 150 up to the user level program to do useful things with this 151 information. This is generally a good idea, so say Y. 152 153config BSD_PROCESS_ACCT_V3 154 bool "BSD Process Accounting version 3 file format" 155 depends on BSD_PROCESS_ACCT 156 default n 157 help 158 If you say Y here, the process accounting information is written 159 in a new file format that also logs the process IDs of each 160 process and it's parent. Note that this file format is incompatible 161 with previous v0/v1/v2 file formats, so you will need updated tools 162 for processing it. A preliminary version of these tools is available 163 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 164 165config SYSCTL 166 bool "Sysctl support" 167 ---help--- 168 The sysctl interface provides a means of dynamically changing 169 certain kernel parameters and variables on the fly without requiring 170 a recompile of the kernel or reboot of the system. The primary 171 interface consists of a system call, but if you say Y to "/proc 172 file system support", a tree of modifiable sysctl entries will be 173 generated beneath the /proc/sys directory. They are explained in the 174 files in <file:Documentation/sysctl/>. Note that enabling this 175 option will enlarge the kernel by at least 8 KB. 176 177 As it is generally a good thing, you should say Y here unless 178 building a kernel for install/rescue disks or your system is very 179 limited in memory. 180 181config AUDIT 182 bool "Auditing support" 183 depends on NET 184 default y if SECURITY_SELINUX 185 help 186 Enable auditing infrastructure that can be used with another 187 kernel subsystem, such as SELinux (which requires this for 188 logging of avc messages output). Does not do system-call 189 auditing without CONFIG_AUDITSYSCALL. 190 191config AUDITSYSCALL 192 bool "Enable system-call auditing support" 193 depends on AUDIT && (X86 || PPC || PPC64 || ARCH_S390 || IA64 || UML || SPARC64) 194 default y if SECURITY_SELINUX 195 help 196 Enable low-overhead system-call auditing infrastructure that 197 can be used independently or with another kernel subsystem, 198 such as SELinux. 199 200config HOTPLUG 201 bool "Support for hot-pluggable devices" if !ARCH_S390 202 default ARCH_S390 203 help 204 This option is provided for the case where no in-kernel-tree 205 modules require HOTPLUG functionality, but a module built 206 outside the kernel tree does. Such modules require Y here. 207 208config KOBJECT_UEVENT 209 bool "Kernel Userspace Events" if EMBEDDED 210 depends on NET 211 default y 212 help 213 This option enables the kernel userspace event layer, which is a 214 simple mechanism for kernel-to-user communication over a netlink 215 socket. 216 The goal of the kernel userspace events layer is to provide a simple 217 and efficient events system, that notifies userspace about kobject 218 state changes. This will enable applications to just listen for 219 events instead of polling system devices and files. 220 Hotplug events (kobject addition and removal) are also available on 221 the netlink socket in addition to the execution of /sbin/hotplug if 222 CONFIG_HOTPLUG is enabled. 223 224 Say Y, unless you are building a system requiring minimal memory 225 consumption. 226 227config IKCONFIG 228 bool "Kernel .config support" 229 ---help--- 230 This option enables the complete Linux kernel ".config" file 231 contents to be saved in the kernel. It provides documentation 232 of which kernel options are used in a running kernel or in an 233 on-disk kernel. This information can be extracted from the kernel 234 image file with the script scripts/extract-ikconfig and used as 235 input to rebuild the current kernel or to build another kernel. 236 It can also be extracted from a running kernel by reading 237 /proc/config.gz if enabled (below). 238 239config IKCONFIG_PROC 240 bool "Enable access to .config through /proc/config.gz" 241 depends on IKCONFIG && PROC_FS 242 ---help--- 243 This option enables access to the kernel configuration file 244 through /proc/config.gz. 245 246config CPUSETS 247 bool "Cpuset support" 248 depends on SMP 249 help 250 This option will let you create and manage CPUSETs which 251 allow dynamically partitioning a system into sets of CPUs and 252 Memory Nodes and assigning tasks to run only within those sets. 253 This is primarily useful on large SMP or NUMA systems. 254 255 Say N if unsure. 256 257source "usr/Kconfig" 258 259config CC_OPTIMIZE_FOR_SIZE 260 bool "Optimize for size (Look out for broken compilers!)" 261 default y 262 depends on ARM || H8300 || EXPERIMENTAL 263 depends on !SPARC64 264 help 265 Enabling this option will pass "-Os" instead of "-O2" to gcc 266 resulting in a smaller kernel. 267 268 WARNING: some versions of gcc may generate incorrect code with this 269 option. If problems are observed, a gcc upgrade may be needed. 270 271 If unsure, say N. 272 273menuconfig EMBEDDED 274 bool "Configure standard kernel features (for small systems)" 275 help 276 This option allows certain base kernel options and settings 277 to be disabled or tweaked. This is for specialized 278 environments which can tolerate a "non-standard" kernel. 279 Only use this if you really know what you are doing. 280 281config KALLSYMS 282 bool "Load all symbols for debugging/kksymoops" if EMBEDDED 283 default y 284 help 285 Say Y here to let the kernel print out symbolic crash information and 286 symbolic stack backtraces. This increases the size of the kernel 287 somewhat, as all symbols have to be loaded into the kernel image. 288 289config KALLSYMS_ALL 290 bool "Include all symbols in kallsyms" 291 depends on DEBUG_KERNEL && KALLSYMS 292 help 293 Normally kallsyms only contains the symbols of functions, for nicer 294 OOPS messages. Some debuggers can use kallsyms for other 295 symbols too: say Y here to include all symbols, if you need them 296 and you don't care about adding 300k to the size of your kernel. 297 298 Say N. 299 300config KALLSYMS_EXTRA_PASS 301 bool "Do an extra kallsyms pass" 302 depends on KALLSYMS 303 help 304 If kallsyms is not working correctly, the build will fail with 305 inconsistent kallsyms data. If that occurs, log a bug report and 306 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 307 Always say N here unless you find a bug in kallsyms, which must be 308 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 309 you wait for kallsyms to be fixed. 310 311 312config PRINTK 313 default y 314 bool "Enable support for printk" if EMBEDDED 315 help 316 This option enables normal printk support. Removing it 317 eliminates most of the message strings from the kernel image 318 and makes the kernel more or less silent. As this makes it 319 very difficult to diagnose system problems, saying N here is 320 strongly discouraged. 321 322config BUG 323 bool "BUG() support" if EMBEDDED 324 default y 325 help 326 Disabling this option eliminates support for BUG and WARN, reducing 327 the size of your kernel image and potentially quietly ignoring 328 numerous fatal conditions. You should only consider disabling this 329 option for embedded systems with no facilities for reporting errors. 330 Just say Y. 331 332config BASE_FULL 333 default y 334 bool "Enable full-sized data structures for core" if EMBEDDED 335 help 336 Disabling this option reduces the size of miscellaneous core 337 kernel data structures. This saves memory on small machines, 338 but may reduce performance. 339 340config FUTEX 341 bool "Enable futex support" if EMBEDDED 342 default y 343 help 344 Disabling this option will cause the kernel to be built without 345 support for "fast userspace mutexes". The resulting kernel may not 346 run glibc-based applications correctly. 347 348config EPOLL 349 bool "Enable eventpoll support" if EMBEDDED 350 default y 351 help 352 Disabling this option will cause the kernel to be built without 353 support for epoll family of system calls. 354 355config SHMEM 356 bool "Use full shmem filesystem" if EMBEDDED 357 default y 358 depends on MMU 359 help 360 The shmem is an internal filesystem used to manage shared memory. 361 It is backed by swap and manages resource limits. It is also exported 362 to userspace as tmpfs if TMPFS is enabled. Disabling this 363 option replaces shmem and tmpfs with the much simpler ramfs code, 364 which may be appropriate on small systems without swap. 365 366config CC_ALIGN_FUNCTIONS 367 int "Function alignment" if EMBEDDED 368 default 0 369 help 370 Align the start of functions to the next power-of-two greater than n, 371 skipping up to n bytes. For instance, 32 aligns functions 372 to the next 32-byte boundary, but 24 would align to the next 373 32-byte boundary only if this can be done by skipping 23 bytes or less. 374 Zero means use compiler's default. 375 376config CC_ALIGN_LABELS 377 int "Label alignment" if EMBEDDED 378 default 0 379 help 380 Align all branch targets to a power-of-two boundary, skipping 381 up to n bytes like ALIGN_FUNCTIONS. This option can easily 382 make code slower, because it must insert dummy operations for 383 when the branch target is reached in the usual flow of the code. 384 Zero means use compiler's default. 385 386config CC_ALIGN_LOOPS 387 int "Loop alignment" if EMBEDDED 388 default 0 389 help 390 Align loops to a power-of-two boundary, skipping up to n bytes. 391 Zero means use compiler's default. 392 393config CC_ALIGN_JUMPS 394 int "Jump alignment" if EMBEDDED 395 default 0 396 help 397 Align branch targets to a power-of-two boundary, for branch 398 targets where the targets can only be reached by jumping, 399 skipping up to n bytes like ALIGN_FUNCTIONS. In this case, 400 no dummy operations need be executed. 401 Zero means use compiler's default. 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 414menu "Loadable module support" 415 416config MODULES 417 bool "Enable loadable module support" 418 help 419 Kernel modules are small pieces of compiled code which can 420 be inserted in the running kernel, rather than being 421 permanently built into the kernel. You use the "modprobe" 422 tool to add (and sometimes remove) them. If you say Y here, 423 many parts of the kernel can be built as modules (by 424 answering M instead of Y where indicated): this is most 425 useful for infrequently used options which are not required 426 for booting. For more information, see the man pages for 427 modprobe, lsmod, modinfo, insmod and rmmod. 428 429 If you say Y here, you will need to run "make 430 modules_install" to put the modules under /lib/modules/ 431 where modprobe can find them (you may need to be root to do 432 this). 433 434 If unsure, say Y. 435 436config MODULE_UNLOAD 437 bool "Module unloading" 438 depends on MODULES 439 help 440 Without this option you will not be able to unload any 441 modules (note that some modules may not be unloadable 442 anyway), which makes your kernel slightly smaller and 443 simpler. If unsure, say Y. 444 445config MODULE_FORCE_UNLOAD 446 bool "Forced module unloading" 447 depends on MODULE_UNLOAD && EXPERIMENTAL 448 help 449 This option allows you to force a module to unload, even if the 450 kernel believes it is unsafe: the kernel will remove the module 451 without waiting for anyone to stop using it (using the -f option to 452 rmmod). This is mainly for kernel developers and desperate users. 453 If unsure, say N. 454 455config OBSOLETE_MODPARM 456 bool 457 default y 458 depends on MODULES 459 help 460 You need this option to use module parameters on modules which 461 have not been converted to the new module parameter system yet. 462 If unsure, say Y. 463 464config MODVERSIONS 465 bool "Module versioning support (EXPERIMENTAL)" 466 depends on MODULES && EXPERIMENTAL 467 help 468 Usually, you have to use modules compiled with your kernel. 469 Saying Y here makes it sometimes possible to use modules 470 compiled for different kernels, by adding enough information 471 to the modules to (hopefully) spot any changes which would 472 make them incompatible with the kernel you are running. If 473 unsure, say N. 474 475config MODULE_SRCVERSION_ALL 476 bool "Source checksum for all modules" 477 depends on MODULES 478 help 479 Modules which contain a MODULE_VERSION get an extra "srcversion" 480 field inserted into their modinfo section, which contains a 481 sum of the source files which made it. This helps maintainers 482 see exactly which source was used to build a module (since 483 others sometimes change the module source without updating 484 the version). With this option, such a "srcversion" field 485 will be created for all modules. If unsure, say N. 486 487config KMOD 488 bool "Automatic kernel module loading" 489 depends on MODULES 490 help 491 Normally when you have selected some parts of the kernel to 492 be created as kernel modules, you must load them (using the 493 "modprobe" command) before you can use them. If you say Y 494 here, some parts of the kernel will be able to load modules 495 automatically: when a part of the kernel needs a module, it 496 runs modprobe with the appropriate arguments, thereby 497 loading the module if it is available. If unsure, say Y. 498 499config STOP_MACHINE 500 bool 501 default y 502 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 503 help 504 Need stop_machine() primitive. 505endmenu 506 507menu "Block layer" 508source "block/Kconfig" 509endmenu 510