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 These are 24 drivers that have been replaced by something else, and/or are 25 scheduled to be removed in a future kernel release. 26 27 Unless you intend to help test and develop a feature or driver that 28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 This is the value of the two limits on the number of argument and of 64 env.var 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 SWAP 81 bool "Support for paging of anonymous memory (swap)" 82 depends on MMU 83 default y 84 help 85 This option allows you to choose whether you want to have support 86 for socalled swap devices or swap files in your kernel that are 87 used to provide more virtual memory than the actual RAM present 88 in your computer. If unsure say Y. 89 90config SYSVIPC 91 bool "System V IPC" 92 depends on MMU 93 ---help--- 94 Inter Process Communication is a suite of library functions and 95 system calls which let processes (running programs) synchronize and 96 exchange information. It is generally considered to be a good thing, 97 and some programs won't run unless you say Y here. In particular, if 98 you want to run the DOS emulator dosemu under Linux (read the 99 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 100 you'll need to say Y here. 101 102 You can find documentation about IPC with "info ipc" and also in 103 section 6.4 of the Linux Programmer's Guide, available from 104 <http://www.tldp.org/guides.html>. 105 106config POSIX_MQUEUE 107 bool "POSIX Message Queues" 108 depends on NET && EXPERIMENTAL 109 ---help--- 110 POSIX variant of message queues is a part of IPC. In POSIX message 111 queues every message has a priority which decides about succession 112 of receiving it by a process. If you want to compile and run 113 programs written e.g. for Solaris with use of its POSIX message 114 queues (functions mq_*) say Y here. To use this feature you will 115 also need mqueue library, available from 116 <http://www.mat.uni.torun.pl/~wrona/posix_ipc/> 117 118 POSIX message queues are visible as a filesystem called 'mqueue' 119 and can be mounted somewhere if you want to do filesystem 120 operations on message queues. 121 122 If unsure, say Y. 123 124config BSD_PROCESS_ACCT 125 bool "BSD Process Accounting" 126 help 127 If you say Y here, a user level program will be able to instruct the 128 kernel (via a special system call) to write process accounting 129 information to a file: whenever a process exits, information about 130 that process will be appended to the file by the kernel. The 131 information includes things such as creation time, owning user, 132 command name, memory usage, controlling terminal etc. (the complete 133 list is in the struct acct in <file:include/linux/acct.h>). It is 134 up to the user level program to do useful things with this 135 information. This is generally a good idea, so say Y. 136 137config BSD_PROCESS_ACCT_V3 138 bool "BSD Process Accounting version 3 file format" 139 depends on BSD_PROCESS_ACCT 140 default n 141 help 142 If you say Y here, the process accounting information is written 143 in a new file format that also logs the process IDs of each 144 process and it's parent. Note that this file format is incompatible 145 with previous v0/v1/v2 file formats, so you will need updated tools 146 for processing it. A preliminary version of these tools is available 147 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 148 149config SYSCTL 150 bool "Sysctl support" 151 ---help--- 152 The sysctl interface provides a means of dynamically changing 153 certain kernel parameters and variables on the fly without requiring 154 a recompile of the kernel or reboot of the system. The primary 155 interface consists of a system call, but if you say Y to "/proc 156 file system support", a tree of modifiable sysctl entries will be 157 generated beneath the /proc/sys directory. They are explained in the 158 files in <file:Documentation/sysctl/>. Note that enabling this 159 option will enlarge the kernel by at least 8 KB. 160 161 As it is generally a good thing, you should say Y here unless 162 building a kernel for install/rescue disks or your system is very 163 limited in memory. 164 165config AUDIT 166 bool "Auditing support" 167 default y if SECURITY_SELINUX 168 help 169 Enable auditing infrastructure that can be used with another 170 kernel subsystem, such as SELinux (which requires this for 171 logging of avc messages output). Does not do system-call 172 auditing without CONFIG_AUDITSYSCALL. 173 174config AUDITSYSCALL 175 bool "Enable system-call auditing support" 176 depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64 || UML) 177 default y if SECURITY_SELINUX 178 help 179 Enable low-overhead system-call auditing infrastructure that 180 can be used independently or with another kernel subsystem, 181 such as SELinux. 182 183config HOTPLUG 184 bool "Support for hot-pluggable devices" if !ARCH_S390 185 default ARCH_S390 186 help 187 This option is provided for the case where no in-kernel-tree 188 modules require HOTPLUG functionality, but a module built 189 outside the kernel tree does. Such modules require Y here. 190 191config KOBJECT_UEVENT 192 bool "Kernel Userspace Events" 193 depends on NET 194 default y 195 help 196 This option enables the kernel userspace event layer, which is a 197 simple mechanism for kernel-to-user communication over a netlink 198 socket. 199 The goal of the kernel userspace events layer is to provide a simple 200 and efficient events system, that notifies userspace about kobject 201 state changes. This will enable applications to just listen for 202 events instead of polling system devices and files. 203 Hotplug events (kobject addition and removal) are also available on 204 the netlink socket in addition to the execution of /sbin/hotplug if 205 CONFIG_HOTPLUG is enabled. 206 207 Say Y, unless you are building a system requiring minimal memory 208 consumption. 209 210config IKCONFIG 211 bool "Kernel .config support" 212 ---help--- 213 This option enables the complete Linux kernel ".config" file 214 contents to be saved in the kernel. It provides documentation 215 of which kernel options are used in a running kernel or in an 216 on-disk kernel. This information can be extracted from the kernel 217 image file with the script scripts/extract-ikconfig and used as 218 input to rebuild the current kernel or to build another kernel. 219 It can also be extracted from a running kernel by reading 220 /proc/config.gz if enabled (below). 221 222config IKCONFIG_PROC 223 bool "Enable access to .config through /proc/config.gz" 224 depends on IKCONFIG && PROC_FS 225 ---help--- 226 This option enables access to the kernel configuration file 227 through /proc/config.gz. 228 229config CPUSETS 230 bool "Cpuset support" 231 depends on SMP 232 help 233 This options will let you create and manage CPUSET's which 234 allow dynamically partitioning a system into sets of CPUs and 235 Memory Nodes and assigning tasks to run only within those sets. 236 This is primarily useful on large SMP or NUMA systems. 237 238 Say N if unsure. 239 240menuconfig EMBEDDED 241 bool "Configure standard kernel features (for small systems)" 242 help 243 This option allows certain base kernel options and settings 244 to be disabled or tweaked. This is for specialized 245 environments which can tolerate a "non-standard" kernel. 246 Only use this if you really know what you are doing. 247 248config KALLSYMS 249 bool "Load all symbols for debugging/kksymoops" if EMBEDDED 250 default y 251 help 252 Say Y here to let the kernel print out symbolic crash information and 253 symbolic stack backtraces. This increases the size of the kernel 254 somewhat, as all symbols have to be loaded into the kernel image. 255 256config KALLSYMS_ALL 257 bool "Include all symbols in kallsyms" 258 depends on DEBUG_KERNEL && KALLSYMS 259 help 260 Normally kallsyms only contains the symbols of functions, for nicer 261 OOPS messages. Some debuggers can use kallsyms for other 262 symbols too: say Y here to include all symbols, and you 263 don't care about adding 300k to the size of your kernel. 264 265 Say N. 266 267config KALLSYMS_EXTRA_PASS 268 bool "Do an extra kallsyms pass" 269 depends on KALLSYMS 270 help 271 If kallsyms is not working correctly, the build will fail with 272 inconsistent kallsyms data. If that occurs, log a bug report and 273 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 274 Always say N here unless you find a bug in kallsyms, which must be 275 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 276 you wait for kallsyms to be fixed. 277 278 279config PRINTK 280 default y 281 bool "Enable support for printk" if EMBEDDED 282 help 283 This option enables normal printk support. Removing it 284 eliminates most of the message strings from the kernel image 285 and makes the kernel more or less silent. As this makes it 286 very difficult to diagnose system problems, saying N here is 287 strongly discouraged. 288 289config BUG 290 bool "BUG() support" if EMBEDDED 291 default y 292 help 293 Disabling this option eliminates support for BUG and WARN, reducing 294 the size of your kernel image and potentially quietly ignoring 295 numerous fatal conditions. You should only consider disabling this 296 option for embedded systems with no facilities for reporting errors. 297 Just say Y. 298 299config BASE_FULL 300 default y 301 bool "Enable full-sized data structures for core" if EMBEDDED 302 help 303 Disabling this option reduces the size of miscellaneous core 304 kernel data structures. This saves memory on small machines, 305 but may reduce performance. 306 307config FUTEX 308 bool "Enable futex support" if EMBEDDED 309 default y 310 help 311 Disabling this option will cause the kernel to be built without 312 support for "fast userspace mutexes". The resulting kernel may not 313 run glibc-based applications correctly. 314 315config EPOLL 316 bool "Enable eventpoll support" if EMBEDDED 317 default y 318 help 319 Disabling this option will cause the kernel to be built without 320 support for epoll family of system calls. 321 322config CC_OPTIMIZE_FOR_SIZE 323 bool "Optimize for size" if EMBEDDED 324 default y if ARM || H8300 325 help 326 Enabling this option will pass "-Os" instead of "-O2" to gcc 327 resulting in a smaller kernel. 328 329 WARNING: some versions of gcc may generate incorrect code with this 330 option. If problems are observed, a gcc upgrade may be needed. 331 332 If unsure, say N. 333 334config SHMEM 335 bool "Use full shmem filesystem" if EMBEDDED 336 default y 337 depends on MMU 338 help 339 The shmem is an internal filesystem used to manage shared memory. 340 It is backed by swap and manages resource limits. It is also exported 341 to userspace as tmpfs if TMPFS is enabled. Disabling this 342 option replaces shmem and tmpfs with the much simpler ramfs code, 343 which may be appropriate on small systems without swap. 344 345config CC_ALIGN_FUNCTIONS 346 int "Function alignment" if EMBEDDED 347 default 0 348 help 349 Align the start of functions to the next power-of-two greater than n, 350 skipping up to n bytes. For instance, 32 aligns functions 351 to the next 32-byte boundary, but 24 would align to the next 352 32-byte boundary only if this can be done by skipping 23 bytes or less. 353 Zero means use compiler's default. 354 355config CC_ALIGN_LABELS 356 int "Label alignment" if EMBEDDED 357 default 0 358 help 359 Align all branch targets to a power-of-two boundary, skipping 360 up to n bytes like ALIGN_FUNCTIONS. This option can easily 361 make code slower, because it must insert dummy operations for 362 when the branch target is reached in the usual flow of the code. 363 Zero means use compiler's default. 364 365config CC_ALIGN_LOOPS 366 int "Loop alignment" if EMBEDDED 367 default 0 368 help 369 Align loops to a power-of-two boundary, skipping up to n bytes. 370 Zero means use compiler's default. 371 372config CC_ALIGN_JUMPS 373 int "Jump alignment" if EMBEDDED 374 default 0 375 help 376 Align branch targets to a power-of-two boundary, for branch 377 targets where the targets can only be reached by jumping, 378 skipping up to n bytes like ALIGN_FUNCTIONS. In this case, 379 no dummy operations need be executed. 380 Zero means use compiler's default. 381 382endmenu # General setup 383 384config TINY_SHMEM 385 default !SHMEM 386 bool 387 388config BASE_SMALL 389 int 390 default 0 if BASE_FULL 391 default 1 if !BASE_FULL 392 393menu "Loadable module support" 394 395config MODULES 396 bool "Enable loadable module support" 397 help 398 Kernel modules are small pieces of compiled code which can 399 be inserted in the running kernel, rather than being 400 permanently built into the kernel. You use the "modprobe" 401 tool to add (and sometimes remove) them. If you say Y here, 402 many parts of the kernel can be built as modules (by 403 answering M instead of Y where indicated): this is most 404 useful for infrequently used options which are not required 405 for booting. For more information, see the man pages for 406 modprobe, lsmod, modinfo, insmod and rmmod. 407 408 If you say Y here, you will need to run "make 409 modules_install" to put the modules under /lib/modules/ 410 where modprobe can find them (you may need to be root to do 411 this). 412 413 If unsure, say Y. 414 415config MODULE_UNLOAD 416 bool "Module unloading" 417 depends on MODULES 418 help 419 Without this option you will not be able to unload any 420 modules (note that some modules may not be unloadable 421 anyway), which makes your kernel slightly smaller and 422 simpler. If unsure, say Y. 423 424config MODULE_FORCE_UNLOAD 425 bool "Forced module unloading" 426 depends on MODULE_UNLOAD && EXPERIMENTAL 427 help 428 This option allows you to force a module to unload, even if the 429 kernel believes it is unsafe: the kernel will remove the module 430 without waiting for anyone to stop using it (using the -f option to 431 rmmod). This is mainly for kernel developers and desperate users. 432 If unsure, say N. 433 434config OBSOLETE_MODPARM 435 bool 436 default y 437 depends on MODULES 438 help 439 You need this option to use module parameters on modules which 440 have not been converted to the new module parameter system yet. 441 If unsure, say Y. 442 443config MODVERSIONS 444 bool "Module versioning support (EXPERIMENTAL)" 445 depends on MODULES && EXPERIMENTAL && !UML 446 help 447 Usually, you have to use modules compiled with your kernel. 448 Saying Y here makes it sometimes possible to use modules 449 compiled for different kernels, by adding enough information 450 to the modules to (hopefully) spot any changes which would 451 make them incompatible with the kernel you are running. If 452 unsure, say N. 453 454config MODULE_SRCVERSION_ALL 455 bool "Source checksum for all modules" 456 depends on MODULES 457 help 458 Modules which contain a MODULE_VERSION get an extra "srcversion" 459 field inserted into their modinfo section, which contains a 460 sum of the source files which made it. This helps maintainers 461 see exactly which source was used to build a module (since 462 others sometimes change the module source without updating 463 the version). With this option, such a "srcversion" field 464 will be created for all modules. If unsure, say N. 465 466config KMOD 467 bool "Automatic kernel module loading" 468 depends on MODULES 469 help 470 Normally when you have selected some parts of the kernel to 471 be created as kernel modules, you must load them (using the 472 "modprobe" command) before you can use them. If you say Y 473 here, some parts of the kernel will be able to load modules 474 automatically: when a part of the kernel needs a module, it 475 runs modprobe with the appropriate arguments, thereby 476 loading the module if it is available. If unsure, say Y. 477 478config STOP_MACHINE 479 bool 480 default y 481 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 482 help 483 Need stop_machine() primitive. 484endmenu 485