1config DEFCONFIG_LIST 2 string 3 depends on !UML 4 option defconfig_list 5 default "/lib/modules/$UNAME_RELEASE/.config" 6 default "/etc/kernel-config" 7 default "/boot/config-$UNAME_RELEASE" 8 default "arch/$ARCH/defconfig" 9 10menu "General setup" 11 12config EXPERIMENTAL 13 bool "Prompt for development and/or incomplete code/drivers" 14 ---help--- 15 Some of the various things that Linux supports (such as network 16 drivers, file systems, network protocols, etc.) can be in a state 17 of development where the functionality, stability, or the level of 18 testing is not yet high enough for general use. This is usually 19 known as the "alpha-test" phase among developers. If a feature is 20 currently in alpha-test, then the developers usually discourage 21 uninformed widespread use of this feature by the general public to 22 avoid "Why doesn't this work?" type mail messages. However, active 23 testing and use of these systems is welcomed. Just be aware that it 24 may not meet the normal level of reliability or it may fail to work 25 in some special cases. Detailed bug reports from people familiar 26 with the kernel internals are usually welcomed by the developers 27 (before submitting bug reports, please read the documents 28 <file:README>, <file:MAINTAINERS>, <file:REPORTING-BUGS>, 29 <file:Documentation/BUG-HUNTING>, and 30 <file:Documentation/oops-tracing.txt> in the kernel source). 31 32 This option will also make obsoleted drivers available. These are 33 drivers that have been replaced by something else, and/or are 34 scheduled to be removed in a future kernel release. 35 36 Unless you intend to help test and develop a feature or driver that 37 falls into this category, or you have a situation that requires 38 using these features, you should probably say N here, which will 39 cause the configurator to present you with fewer choices. If 40 you say Y here, you will be offered the choice of using features or 41 drivers that are currently considered to be in the alpha-test phase. 42 43config BROKEN 44 bool 45 46config BROKEN_ON_SMP 47 bool 48 depends on BROKEN || !SMP 49 default y 50 51config LOCK_KERNEL 52 bool 53 depends on SMP || PREEMPT 54 default y 55 56config INIT_ENV_ARG_LIMIT 57 int 58 default 32 if !UML 59 default 128 if UML 60 help 61 Maximum of each of the number of arguments and environment 62 variables passed to init from the kernel command line. 63 64 65config LOCALVERSION 66 string "Local version - append to kernel release" 67 help 68 Append an extra string to the end of your kernel version. 69 This will show up when you type uname, for example. 70 The string you set here will be appended after the contents of 71 any files with a filename matching localversion* in your 72 object and source tree, in that order. Your total string can 73 be a maximum of 64 characters. 74 75config LOCALVERSION_AUTO 76 bool "Automatically append version information to the version string" 77 default y 78 help 79 This will try to automatically determine if the current tree is a 80 release tree by looking for git tags that belong to the current 81 top of tree revision. 82 83 A string of the format -gxxxxxxxx will be added to the localversion 84 if a git-based tree is found. The string generated by this will be 85 appended after any matching localversion* files, and after the value 86 set in CONFIG_LOCALVERSION. 87 88 (The actual string used here is the first eight characters produced 89 by running the command: 90 91 $ git rev-parse --verify HEAD 92 93 which is done within the script "scripts/setlocalversion".) 94 95config SWAP 96 bool "Support for paging of anonymous memory (swap)" 97 depends on MMU && BLOCK 98 default y 99 help 100 This option allows you to choose whether you want to have support 101 for so called swap devices or swap files in your kernel that are 102 used to provide more virtual memory than the actual RAM present 103 in your computer. If unsure say Y. 104 105config SYSVIPC 106 bool "System V IPC" 107 ---help--- 108 Inter Process Communication is a suite of library functions and 109 system calls which let processes (running programs) synchronize and 110 exchange information. It is generally considered to be a good thing, 111 and some programs won't run unless you say Y here. In particular, if 112 you want to run the DOS emulator dosemu under Linux (read the 113 DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), 114 you'll need to say Y here. 115 116 You can find documentation about IPC with "info ipc" and also in 117 section 6.4 of the Linux Programmer's Guide, available from 118 <http://www.tldp.org/guides.html>. 119 120config SYSVIPC_SYSCTL 121 bool 122 depends on SYSVIPC 123 depends on SYSCTL 124 default y 125 126config POSIX_MQUEUE 127 bool "POSIX Message Queues" 128 depends on NET && EXPERIMENTAL 129 ---help--- 130 POSIX variant of message queues is a part of IPC. In POSIX message 131 queues every message has a priority which decides about succession 132 of receiving it by a process. If you want to compile and run 133 programs written e.g. for Solaris with use of its POSIX message 134 queues (functions mq_*) say Y here. 135 136 POSIX message queues are visible as a filesystem called 'mqueue' 137 and can be mounted somewhere if you want to do filesystem 138 operations on message queues. 139 140 If unsure, say Y. 141 142config BSD_PROCESS_ACCT 143 bool "BSD Process Accounting" 144 help 145 If you say Y here, a user level program will be able to instruct the 146 kernel (via a special system call) to write process accounting 147 information to a file: whenever a process exits, information about 148 that process will be appended to the file by the kernel. The 149 information includes things such as creation time, owning user, 150 command name, memory usage, controlling terminal etc. (the complete 151 list is in the struct acct in <file:include/linux/acct.h>). It is 152 up to the user level program to do useful things with this 153 information. This is generally a good idea, so say Y. 154 155config BSD_PROCESS_ACCT_V3 156 bool "BSD Process Accounting version 3 file format" 157 depends on BSD_PROCESS_ACCT 158 default n 159 help 160 If you say Y here, the process accounting information is written 161 in a new file format that also logs the process IDs of each 162 process and it's parent. Note that this file format is incompatible 163 with previous v0/v1/v2 file formats, so you will need updated tools 164 for processing it. A preliminary version of these tools is available 165 at <http://www.physik3.uni-rostock.de/tim/kernel/utils/acct/>. 166 167config TASKSTATS 168 bool "Export task/process statistics through netlink (EXPERIMENTAL)" 169 depends on NET 170 default n 171 help 172 Export selected statistics for tasks/processes through the 173 generic netlink interface. Unlike BSD process accounting, the 174 statistics are available during the lifetime of tasks/processes as 175 responses to commands. Like BSD accounting, they are sent to user 176 space on task exit. 177 178 Say N if unsure. 179 180config TASK_DELAY_ACCT 181 bool "Enable per-task delay accounting (EXPERIMENTAL)" 182 depends on TASKSTATS 183 help 184 Collect information on time spent by a task waiting for system 185 resources like cpu, synchronous block I/O completion and swapping 186 in pages. Such statistics can help in setting a task's priorities 187 relative to other tasks for cpu, io, rss limits etc. 188 189 Say N if unsure. 190 191config TASK_XACCT 192 bool "Enable extended accounting over taskstats (EXPERIMENTAL)" 193 depends on TASKSTATS 194 help 195 Collect extended task accounting data and send the data 196 to userland for processing over the taskstats interface. 197 198 Say N if unsure. 199 200config TASK_IO_ACCOUNTING 201 bool "Enable per-task storage I/O accounting (EXPERIMENTAL)" 202 depends on TASK_XACCT 203 help 204 Collect information on the number of bytes of storage I/O which this 205 task has caused. 206 207 Say N if unsure. 208 209config USER_NS 210 bool "User Namespaces (EXPERIMENTAL)" 211 default n 212 depends on EXPERIMENTAL 213 help 214 Support user namespaces. This allows containers, i.e. 215 vservers, to use user namespaces to provide different 216 user info for different servers. If unsure, say N. 217 218config AUDIT 219 bool "Auditing support" 220 depends on NET 221 help 222 Enable auditing infrastructure that can be used with another 223 kernel subsystem, such as SELinux (which requires this for 224 logging of avc messages output). Does not do system-call 225 auditing without CONFIG_AUDITSYSCALL. 226 227config AUDITSYSCALL 228 bool "Enable system-call auditing support" 229 depends on AUDIT && (X86 || PPC || PPC64 || S390 || IA64 || UML || SPARC64) 230 default y if SECURITY_SELINUX 231 help 232 Enable low-overhead system-call auditing infrastructure that 233 can be used independently or with another kernel subsystem, 234 such as SELinux. To use audit's filesystem watch feature, please 235 ensure that INOTIFY is configured. 236 237config IKCONFIG 238 tristate "Kernel .config support" 239 ---help--- 240 This option enables the complete Linux kernel ".config" file 241 contents to be saved in the kernel. It provides documentation 242 of which kernel options are used in a running kernel or in an 243 on-disk kernel. This information can be extracted from the kernel 244 image file with the script scripts/extract-ikconfig and used as 245 input to rebuild the current kernel or to build another kernel. 246 It can also be extracted from a running kernel by reading 247 /proc/config.gz if enabled (below). 248 249config IKCONFIG_PROC 250 bool "Enable access to .config through /proc/config.gz" 251 depends on IKCONFIG && PROC_FS 252 ---help--- 253 This option enables access to the kernel configuration file 254 through /proc/config.gz. 255 256config LOG_BUF_SHIFT 257 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" 258 range 12 21 259 default 17 if S390 || LOCKDEP 260 default 16 if X86_NUMAQ || IA64 261 default 15 if SMP 262 default 14 263 help 264 Select kernel log buffer size as a power of 2. 265 Defaults and Examples: 266 17 => 128 KB for S/390 267 16 => 64 KB for x86 NUMAQ or IA-64 268 15 => 32 KB for SMP 269 14 => 16 KB for uniprocessor 270 13 => 8 KB 271 12 => 4 KB 272 273config CPUSETS 274 bool "Cpuset support" 275 depends on SMP 276 help 277 This option will let you create and manage CPUSETs which 278 allow dynamically partitioning a system into sets of CPUs and 279 Memory Nodes and assigning tasks to run only within those sets. 280 This is primarily useful on large SMP or NUMA systems. 281 282 Say N if unsure. 283 284config SYSFS_DEPRECATED 285 bool "Create deprecated sysfs files" 286 default y 287 help 288 This option creates deprecated symlinks such as the 289 "device"-link, the <subsystem>:<name>-link, and the 290 "bus"-link. It may also add deprecated key in the 291 uevent environment. 292 None of these features or values should be used today, as 293 they export driver core implementation details to userspace 294 or export properties which can't be kept stable across kernel 295 releases. 296 297 If enabled, this option will also move any device structures 298 that belong to a class, back into the /sys/class hierarchy, in 299 order to support older versions of udev. 300 301 If you are using a distro that was released in 2006 or later, 302 it should be safe to say N here. 303 304config RELAY 305 bool "Kernel->user space relay support (formerly relayfs)" 306 help 307 This option enables support for relay interface support in 308 certain file systems (such as debugfs). 309 It is designed to provide an efficient mechanism for tools and 310 facilities to relay large amounts of data from kernel space to 311 user space. 312 313 If unsure, say N. 314 315config BLK_DEV_INITRD 316 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" 317 depends on BROKEN || !FRV 318 help 319 The initial RAM filesystem is a ramfs which is loaded by the 320 boot loader (loadlin or lilo) and that is mounted as root 321 before the normal boot procedure. It is typically used to 322 load modules needed to mount the "real" root file system, 323 etc. See <file:Documentation/initrd.txt> for details. 324 325 If RAM disk support (BLK_DEV_RAM) is also included, this 326 also enables initial RAM disk (initrd) support and adds 327 15 Kbytes (more on some other architectures) to the kernel size. 328 329 If unsure say Y. 330 331if BLK_DEV_INITRD 332 333source "usr/Kconfig" 334 335endif 336 337config CC_OPTIMIZE_FOR_SIZE 338 bool "Optimize for size (Look out for broken compilers!)" 339 default y 340 depends on ARM || H8300 || SUPERH || EXPERIMENTAL 341 help 342 Enabling this option will pass "-Os" instead of "-O2" to gcc 343 resulting in a smaller kernel. 344 345 WARNING: some versions of gcc may generate incorrect code with this 346 option. If problems are observed, a gcc upgrade may be needed. 347 348 If unsure, say N. 349 350config SYSCTL 351 bool 352 353menuconfig EMBEDDED 354 bool "Configure standard kernel features (for small systems)" 355 help 356 This option allows certain base kernel options and settings 357 to be disabled or tweaked. This is for specialized 358 environments which can tolerate a "non-standard" kernel. 359 Only use this if you really know what you are doing. 360 361config UID16 362 bool "Enable 16-bit UID system calls" if EMBEDDED 363 depends on ARM || BFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && SPARC32_COMPAT) || UML || (X86_64 && IA32_EMULATION) 364 default y 365 help 366 This enables the legacy 16-bit UID syscall wrappers. 367 368config SYSCTL_SYSCALL 369 bool "Sysctl syscall support" if EMBEDDED 370 default y 371 select SYSCTL 372 ---help--- 373 sys_sysctl uses binary paths that have been found challenging 374 to properly maintain and use. The interface in /proc/sys 375 using paths with ascii names is now the primary path to this 376 information. 377 378 Almost nothing using the binary sysctl interface so if you are 379 trying to save some space it is probably safe to disable this, 380 making your kernel marginally smaller. 381 382 If unsure say Y here. 383 384config KALLSYMS 385 bool "Load all symbols for debugging/ksymoops" if EMBEDDED 386 default y 387 help 388 Say Y here to let the kernel print out symbolic crash information and 389 symbolic stack backtraces. This increases the size of the kernel 390 somewhat, as all symbols have to be loaded into the kernel image. 391 392config KALLSYMS_ALL 393 bool "Include all symbols in kallsyms" 394 depends on DEBUG_KERNEL && KALLSYMS 395 help 396 Normally kallsyms only contains the symbols of functions, for nicer 397 OOPS messages. Some debuggers can use kallsyms for other 398 symbols too: say Y here to include all symbols, if you need them 399 and you don't care about adding 300k to the size of your kernel. 400 401 Say N. 402 403config KALLSYMS_EXTRA_PASS 404 bool "Do an extra kallsyms pass" 405 depends on KALLSYMS 406 help 407 If kallsyms is not working correctly, the build will fail with 408 inconsistent kallsyms data. If that occurs, log a bug report and 409 turn on KALLSYMS_EXTRA_PASS which should result in a stable build. 410 Always say N here unless you find a bug in kallsyms, which must be 411 reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while 412 you wait for kallsyms to be fixed. 413 414 415config HOTPLUG 416 bool "Support for hot-pluggable devices" if EMBEDDED 417 default y 418 help 419 This option is provided for the case where no hotplug or uevent 420 capabilities is wanted by the kernel. You should only consider 421 disabling this option for embedded systems that do not use modules, a 422 dynamic /dev tree, or dynamic device discovery. Just say Y. 423 424config PRINTK 425 default y 426 bool "Enable support for printk" if EMBEDDED 427 help 428 This option enables normal printk support. Removing it 429 eliminates most of the message strings from the kernel image 430 and makes the kernel more or less silent. As this makes it 431 very difficult to diagnose system problems, saying N here is 432 strongly discouraged. 433 434config BUG 435 bool "BUG() support" if EMBEDDED 436 default y 437 help 438 Disabling this option eliminates support for BUG and WARN, reducing 439 the size of your kernel image and potentially quietly ignoring 440 numerous fatal conditions. You should only consider disabling this 441 option for embedded systems with no facilities for reporting errors. 442 Just say Y. 443 444config ELF_CORE 445 default y 446 bool "Enable ELF core dumps" if EMBEDDED 447 help 448 Enable support for generating core dumps. Disabling saves about 4k. 449 450config BASE_FULL 451 default y 452 bool "Enable full-sized data structures for core" if EMBEDDED 453 help 454 Disabling this option reduces the size of miscellaneous core 455 kernel data structures. This saves memory on small machines, 456 but may reduce performance. 457 458config FUTEX 459 bool "Enable futex support" if EMBEDDED 460 default y 461 select RT_MUTEXES 462 help 463 Disabling this option will cause the kernel to be built without 464 support for "fast userspace mutexes". The resulting kernel may not 465 run glibc-based applications correctly. 466 467config ANON_INODES 468 bool 469 470config EPOLL 471 bool "Enable eventpoll support" if EMBEDDED 472 default y 473 select ANON_INODES 474 help 475 Disabling this option will cause the kernel to be built without 476 support for epoll family of system calls. 477 478config SIGNALFD 479 bool "Enable signalfd() system call" if EMBEDDED 480 select ANON_INODES 481 default y 482 help 483 Enable the signalfd() system call that allows to receive signals 484 on a file descriptor. 485 486 If unsure, say Y. 487 488config TIMERFD 489 bool "Enable timerfd() system call" if EMBEDDED 490 select ANON_INODES 491 depends on BROKEN 492 default y 493 help 494 Enable the timerfd() system call that allows to receive timer 495 events on a file descriptor. 496 497 If unsure, say Y. 498 499config EVENTFD 500 bool "Enable eventfd() system call" if EMBEDDED 501 select ANON_INODES 502 default y 503 help 504 Enable the eventfd() system call that allows to receive both 505 kernel notification (ie. KAIO) or userspace notifications. 506 507 If unsure, say Y. 508 509config SHMEM 510 bool "Use full shmem filesystem" if EMBEDDED 511 default y 512 depends on MMU 513 help 514 The shmem is an internal filesystem used to manage shared memory. 515 It is backed by swap and manages resource limits. It is also exported 516 to userspace as tmpfs if TMPFS is enabled. Disabling this 517 option replaces shmem and tmpfs with the much simpler ramfs code, 518 which may be appropriate on small systems without swap. 519 520config VM_EVENT_COUNTERS 521 default y 522 bool "Enable VM event counters for /proc/vmstat" if EMBEDDED 523 help 524 VM event counters are needed for event counts to be shown. 525 This option allows the disabling of the VM event counters 526 on EMBEDDED systems. /proc/vmstat will only show page counts 527 if VM event counters are disabled. 528 529config SLUB_DEBUG 530 default y 531 bool "Enable SLUB debugging support" if EMBEDDED 532 depends on SLUB 533 help 534 SLUB has extensive debug support features. Disabling these can 535 result in significant savings in code size. This also disables 536 SLUB sysfs support. /sys/slab will not exist and there will be 537 no support for cache validation etc. 538 539choice 540 prompt "Choose SLAB allocator" 541 default SLUB 542 help 543 This option allows to select a slab allocator. 544 545config SLAB 546 bool "SLAB" 547 help 548 The regular slab allocator that is established and known to work 549 well in all environments. It organizes cache hot objects in 550 per cpu and per node queues. SLAB is the default choice for 551 a slab allocator. 552 553config SLUB 554 bool "SLUB (Unqueued Allocator)" 555 help 556 SLUB is a slab allocator that minimizes cache line usage 557 instead of managing queues of cached objects (SLAB approach). 558 Per cpu caching is realized using slabs of objects instead 559 of queues of objects. SLUB can use memory efficiently 560 and has enhanced diagnostics. 561 562config SLOB 563 depends on EMBEDDED 564 bool "SLOB (Simple Allocator)" 565 help 566 SLOB replaces the SLAB allocator with a drastically simpler 567 allocator. SLOB is more space efficient than SLAB but does not 568 scale well (single lock for all operations) and is also highly 569 susceptible to fragmentation. SLUB can accomplish a higher object 570 density. It is usually better to use SLUB instead of SLOB. 571 572endchoice 573 574endmenu # General setup 575 576config RT_MUTEXES 577 boolean 578 select PLIST 579 580config TINY_SHMEM 581 default !SHMEM 582 bool 583 584config BASE_SMALL 585 int 586 default 0 if BASE_FULL 587 default 1 if !BASE_FULL 588 589menuconfig MODULES 590 bool "Enable loadable module support" 591 help 592 Kernel modules are small pieces of compiled code which can 593 be inserted in the running kernel, rather than being 594 permanently built into the kernel. You use the "modprobe" 595 tool to add (and sometimes remove) them. If you say Y here, 596 many parts of the kernel can be built as modules (by 597 answering M instead of Y where indicated): this is most 598 useful for infrequently used options which are not required 599 for booting. For more information, see the man pages for 600 modprobe, lsmod, modinfo, insmod and rmmod. 601 602 If you say Y here, you will need to run "make 603 modules_install" to put the modules under /lib/modules/ 604 where modprobe can find them (you may need to be root to do 605 this). 606 607 If unsure, say Y. 608 609config MODULE_UNLOAD 610 bool "Module unloading" 611 depends on MODULES 612 help 613 Without this option you will not be able to unload any 614 modules (note that some modules may not be unloadable 615 anyway), which makes your kernel slightly smaller and 616 simpler. If unsure, say Y. 617 618config MODULE_FORCE_UNLOAD 619 bool "Forced module unloading" 620 depends on MODULE_UNLOAD && EXPERIMENTAL 621 help 622 This option allows you to force a module to unload, even if the 623 kernel believes it is unsafe: the kernel will remove the module 624 without waiting for anyone to stop using it (using the -f option to 625 rmmod). This is mainly for kernel developers and desperate users. 626 If unsure, say N. 627 628config MODVERSIONS 629 bool "Module versioning support" 630 depends on MODULES 631 help 632 Usually, you have to use modules compiled with your kernel. 633 Saying Y here makes it sometimes possible to use modules 634 compiled for different kernels, by adding enough information 635 to the modules to (hopefully) spot any changes which would 636 make them incompatible with the kernel you are running. If 637 unsure, say N. 638 639config MODULE_SRCVERSION_ALL 640 bool "Source checksum for all modules" 641 depends on MODULES 642 help 643 Modules which contain a MODULE_VERSION get an extra "srcversion" 644 field inserted into their modinfo section, which contains a 645 sum of the source files which made it. This helps maintainers 646 see exactly which source was used to build a module (since 647 others sometimes change the module source without updating 648 the version). With this option, such a "srcversion" field 649 will be created for all modules. If unsure, say N. 650 651config KMOD 652 bool "Automatic kernel module loading" 653 depends on MODULES 654 help 655 Normally when you have selected some parts of the kernel to 656 be created as kernel modules, you must load them (using the 657 "modprobe" command) before you can use them. If you say Y 658 here, some parts of the kernel will be able to load modules 659 automatically: when a part of the kernel needs a module, it 660 runs modprobe with the appropriate arguments, thereby 661 loading the module if it is available. If unsure, say Y. 662 663config STOP_MACHINE 664 bool 665 default y 666 depends on (SMP && MODULE_UNLOAD) || HOTPLUG_CPU 667 help 668 Need stop_machine() primitive. 669 670source "block/Kconfig" 671