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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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 ---help--- 109 Inter Process Communication is a suite of library functions and 110 system calls which let processes (running programs) synchronize and 111 exchange information. It is generally considered to be a good thing, 112 and some programs won't run unless you say Y here. In particular, if 113 you want to run the DOS emulator dosemu under Linux (read the 114 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 115 you'll need to say Y here. 116 117 You can find documentation about IPC with "info ipc" and also in 118 section 6.4 of the Linux Programmer's Guide, available from 119 <http://www.tldp.org/guides.html>. 120 121config POSIX_MQUEUE 122 bool "POSIX Message Queues" 123 depends on NET && EXPERIMENTAL 124 ---help--- 125 POSIX variant of message queues is a part of IPC. In POSIX message 126 queues every message has a priority which decides about succession 127 of receiving it by a process. If you want to compile and run 128 programs written e.g. for Solaris with use of its POSIX message 129 queues (functions mq_*) say Y here. To use this feature you will 130 also need mqueue library, available from 131 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/> 132 133 POSIX message queues are visible as a filesystem called 'mqueue' 134 and can be mounted somewhere if you want to do filesystem 135 operations on message queues. 136 137 If unsure, say Y. 138 139config BSD_PROCESS_ACCT 140 bool "BSD Process Accounting" 141 help 142 If you say Y here, a user level program will be able to instruct the 143 kernel (via a special system call) to write process accounting 144 information to a file: whenever a process exits, information about 145 that process will be appended to the file by the kernel. The 146 information includes things such as creation time, owning user, 147 command name, memory usage, controlling terminal etc. (the complete 148 list is in the struct acct in <file:include/linux/acct.h>). It is 149 up to the user level program to do useful things with this 150 information. This is generally a good idea, so say Y. 151 152config BSD_PROCESS_ACCT_V3 153 bool "BSD Process Accounting version 3 file format" 154 depends on BSD_PROCESS_ACCT 155 default n 156 help 157 If you say Y here, the process accounting information is written 158 in a new file format that also logs the process IDs of each 159 process and it's parent. Note that this file format is incompatible 160 with previous v0/v1/v2 file formats, so you will need updated tools 161 for processing it. A preliminary version of these tools is available 162 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 163 164config SYSCTL 165 bool "Sysctl support" 166 ---help--- 167 The sysctl interface provides a means of dynamically changing 168 certain kernel parameters and variables on the fly without requiring 169 a recompile of the kernel or reboot of the system. The primary 170 interface consists of a system call, but if you say Y to "/proc 171 file system support", a tree of modifiable sysctl entries will be 172 generated beneath the /proc/sys directory. They are explained in the 173 files in <file:Documentation/sysctl/>. Note that enabling this 174 option will enlarge the kernel by at least 8 KB. 175 176 As it is generally a good thing, you should say Y here unless 177 building a kernel for install/rescue disks or your system is very 178 limited in memory. 179 180config AUDIT 181 bool "Auditing support" 182 depends on NET 183 default y if SECURITY_SELINUX 184 help 185 Enable auditing infrastructure that can be used with another 186 kernel subsystem, such as SELinux (which requires this for 187 logging of avc messages output). Does not do system-call 188 auditing without CONFIG_AUDITSYSCALL. 189 190config AUDITSYSCALL 191 bool "Enable system-call auditing support" 192 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64) 193 default y if SECURITY_SELINUX 194 help 195 Enable low-overhead system-call auditing infrastructure that 196 can be used independently or with another kernel subsystem, 197 such as SELinux. 198 199config IKCONFIG 200 bool "Kernel .config support" 201 ---help--- 202 This option enables the complete Linux kernel ".config" file 203 contents to be saved in the kernel. It provides documentation 204 of which kernel options are used in a running kernel or in an 205 on-disk kernel. This information can be extracted from the kernel 206 image file with the script scripts/extract-ikconfig and used as 207 input to rebuild the current kernel or to build another kernel. 208 It can also be extracted from a running kernel by reading 209 /proc/config.gz if enabled (below). 210 211config IKCONFIG_PROC 212 bool "Enable access to .config through /proc/config.gz" 213 depends on IKCONFIG && PROC_FS 214 ---help--- 215 This option enables access to the kernel configuration file 216 through /proc/config.gz. 217 218config CPUSETS 219 bool "Cpuset support" 220 depends on SMP 221 help 222 This option will let you create and manage CPUSETs which 223 allow dynamically partitioning a system into sets of CPUs and 224 Memory Nodes and assigning tasks to run only within those sets. 225 This is primarily useful on large SMP or NUMA systems. 226 227 Say N if unsure. 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 DOUBLEFAULT 330 depends X86 331 default y if X86 332 bool "Enable doublefault exception handler" if EMBEDDED 333 help 334 This option allows trapping of rare doublefault exceptions that 335 would otherwise cause a system to silently reboot. Disabling this 336 option saves about 4k. 337 338config ELF_CORE 339 default y 340 bool "Enable ELF core dumps" if EMBEDDED 341 help 342 Enable support for generating core dumps. Disabling saves about 4k. 343 344config BASE_FULL 345 default y 346 bool "Enable full-sized data structures for core" if EMBEDDED 347 help 348 Disabling this option reduces the size of miscellaneous core 349 kernel data structures. This saves memory on small machines, 350 but may reduce performance. 351 352config FUTEX 353 bool "Enable futex support" if EMBEDDED 354 default y 355 help 356 Disabling this option will cause the kernel to be built without 357 support for "fast userspace mutexes". The resulting kernel may not 358 run glibc-based applications correctly. 359 360config EPOLL 361 bool "Enable eventpoll support" if EMBEDDED 362 default y 363 help 364 Disabling this option will cause the kernel to be built without 365 support for epoll family of system calls. 366 367config SHMEM 368 bool "Use full shmem filesystem" if EMBEDDED 369 default y 370 depends on MMU 371 help 372 The shmem is an internal filesystem used to manage shared memory. 373 It is backed by swap and manages resource limits. It is also exported 374 to userspace as tmpfs if TMPFS is enabled. Disabling this 375 option replaces shmem and tmpfs with the much simpler ramfs code, 376 which may be appropriate on small systems without swap. 377 378config CC_ALIGN_FUNCTIONS 379 int "Function alignment" if EMBEDDED 380 default 0 381 help 382 Align the start of functions to the next power-of-two greater than n, 383 skipping up to n bytes. For instance, 32 aligns functions 384 to the next 32-byte boundary, but 24 would align to the next 385 32-byte boundary only if this can be done by skipping 23 bytes or less. 386 Zero means use compiler's default. 387 388config CC_ALIGN_LABELS 389 int "Label alignment" if EMBEDDED 390 default 0 391 help 392 Align all branch targets to a power-of-two boundary, skipping 393 up to n bytes like ALIGN_FUNCTIONS. This option can easily 394 make code slower, because it must insert dummy operations for 395 when the branch target is reached in the usual flow of the code. 396 Zero means use compiler's default. 397 398config CC_ALIGN_LOOPS 399 int "Loop alignment" if EMBEDDED 400 default 0 401 help 402 Align loops to a power-of-two boundary, skipping up to n bytes. 403 Zero means use compiler's default. 404 405config CC_ALIGN_JUMPS 406 int "Jump alignment" if EMBEDDED 407 default 0 408 help 409 Align branch targets to a power-of-two boundary, for branch 410 targets where the targets can only be reached by jumping, 411 skipping up to n bytes like ALIGN_FUNCTIONS. In this case, 412 no dummy operations need be executed. 413 Zero means use compiler's default. 414 415config SLAB 416 default y 417 bool "Use full SLAB allocator" if EMBEDDED 418 help 419 Disabling this replaces the advanced SLAB allocator and 420 kmalloc support with the drastically simpler SLOB allocator. 421 SLOB is more space efficient but does not scale well and is 422 more susceptible to fragmentation. 423 424endmenu # General setup 425 426config TINY_SHMEM 427 default !SHMEM 428 bool 429 430config BASE_SMALL 431 int 432 default 0 if BASE_FULL 433 default 1 if !BASE_FULL 434 435config SLOB 436 default !SLAB 437 bool 438 439menu "Loadable module support" 440 441config MODULES 442 bool "Enable loadable module support" 443 help 444 Kernel modules are small pieces of compiled code which can 445 be inserted in the running kernel, rather than being 446 permanently built into the kernel. You use the "modprobe" 447 tool to add (and sometimes remove) them. If you say Y here, 448 many parts of the kernel can be built as modules (by 449 answering M instead of Y where indicated): this is most 450 useful for infrequently used options which are not required 451 for booting. For more information, see the man pages for 452 modprobe, lsmod, modinfo, insmod and rmmod. 453 454 If you say Y here, you will need to run "make 455 modules_install" to put the modules under /lib/modules/ 456 where modprobe can find them (you may need to be root to do 457 this). 458 459 If unsure, say Y. 460 461config MODULE_UNLOAD 462 bool "Module unloading" 463 depends on MODULES 464 help 465 Without this option you will not be able to unload any 466 modules (note that some modules may not be unloadable 467 anyway), which makes your kernel slightly smaller and 468 simpler. If unsure, say Y. 469 470config MODULE_FORCE_UNLOAD 471 bool "Forced module unloading" 472 depends on MODULE_UNLOAD && EXPERIMENTAL 473 help 474 This option allows you to force a module to unload, even if the 475 kernel believes it is unsafe: the kernel will remove the module 476 without waiting for anyone to stop using it (using the -f option to 477 rmmod). This is mainly for kernel developers and desperate users. 478 If unsure, say N. 479 480config OBSOLETE_MODPARM 481 bool 482 default y 483 depends on MODULES 484 help 485 You need this option to use module parameters on modules which 486 have not been converted to the new module parameter system yet. 487 If unsure, say Y. 488 489config MODVERSIONS 490 bool "Module versioning support" 491 depends on MODULES 492 help 493 Usually, you have to use modules compiled with your kernel. 494 Saying Y here makes it sometimes possible to use modules 495 compiled for different kernels, by adding enough information 496 to the modules to (hopefully) spot any changes which would 497 make them incompatible with the kernel you are running. If 498 unsure, say N. 499 500config MODULE_SRCVERSION_ALL 501 bool "Source checksum for all modules" 502 depends on MODULES 503 help 504 Modules which contain a MODULE_VERSION get an extra "srcversion" 505 field inserted into their modinfo section, which contains a 506 sum of the source files which made it. This helps maintainers 507 see exactly which source was used to build a module (since 508 others sometimes change the module source without updating 509 the version). With this option, such a "srcversion" field 510 will be created for all modules. If unsure, say N. 511 512config KMOD 513 bool "Automatic kernel module loading" 514 depends on MODULES 515 help 516 Normally when you have selected some parts of the kernel to 517 be created as kernel modules, you must load them (using the 518 "modprobe" command) before you can use them. If you say Y 519 here, some parts of the kernel will be able to load modules 520 automatically: when a part of the kernel needs a module, it 521 runs modprobe with the appropriate arguments, thereby 522 loading the module if it is available. If unsure, say Y. 523 524config STOP_MACHINE 525 bool 526 default y 527 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 528 help 529 Need stop_machine() primitive. 530endmenu 531 532menu "Block layer" 533source "block/Kconfig" 534endmenu 535