Kconfig 35 KB

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  1. #
  2. # For a description of the syntax of this configuration file,
  3. # see Documentation/kbuild/kconfig-language.txt.
  4. #
  5. mainmenu "Linux Kernel Configuration"
  6. config X86_32
  7. bool
  8. default y
  9. help
  10. This is Linux's home port. Linux was originally native to the Intel
  11. 386, and runs on all the later x86 processors including the Intel
  12. 486, 586, Pentiums, and various instruction-set-compatible chips by
  13. AMD, Cyrix, and others.
  14. config SEMAPHORE_SLEEPERS
  15. bool
  16. default y
  17. config X86
  18. bool
  19. default y
  20. config MMU
  21. bool
  22. default y
  23. config SBUS
  24. bool
  25. config GENERIC_ISA_DMA
  26. bool
  27. default y
  28. config GENERIC_IOMAP
  29. bool
  30. default y
  31. config ARCH_MAY_HAVE_PC_FDC
  32. bool
  33. default y
  34. config DMI
  35. bool
  36. default y
  37. source "init/Kconfig"
  38. config DOUBLEFAULT
  39. default y
  40. bool "Enable doublefault exception handler" if EMBEDDED
  41. help
  42. This option allows trapping of rare doublefault exceptions that
  43. would otherwise cause a system to silently reboot. Disabling this
  44. option saves about 4k and might cause you much additional grey
  45. hair.
  46. menu "Processor type and features"
  47. choice
  48. prompt "Subarchitecture Type"
  49. default X86_PC
  50. config X86_PC
  51. bool "PC-compatible"
  52. help
  53. Choose this option if your computer is a standard PC or compatible.
  54. config X86_ELAN
  55. bool "AMD Elan"
  56. help
  57. Select this for an AMD Elan processor.
  58. Do not use this option for K6/Athlon/Opteron processors!
  59. If unsure, choose "PC-compatible" instead.
  60. config X86_VOYAGER
  61. bool "Voyager (NCR)"
  62. help
  63. Voyager is an MCA-based 32-way capable SMP architecture proprietary
  64. to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
  65. *** WARNING ***
  66. If you do not specifically know you have a Voyager based machine,
  67. say N here, otherwise the kernel you build will not be bootable.
  68. config X86_NUMAQ
  69. bool "NUMAQ (IBM/Sequent)"
  70. select NUMA
  71. help
  72. This option is used for getting Linux to run on a (IBM/Sequent) NUMA
  73. multiquad box. This changes the way that processors are bootstrapped,
  74. and uses Clustered Logical APIC addressing mode instead of Flat Logical.
  75. You will need a new lynxer.elf file to flash your firmware with - send
  76. email to <Martin.Bligh@us.ibm.com>.
  77. config X86_SUMMIT
  78. bool "Summit/EXA (IBM x440)"
  79. depends on SMP
  80. help
  81. This option is needed for IBM systems that use the Summit/EXA chipset.
  82. In particular, it is needed for the x440.
  83. If you don't have one of these computers, you should say N here.
  84. config X86_BIGSMP
  85. bool "Support for other sub-arch SMP systems with more than 8 CPUs"
  86. depends on SMP
  87. help
  88. This option is needed for the systems that have more than 8 CPUs
  89. and if the system is not of any sub-arch type above.
  90. If you don't have such a system, you should say N here.
  91. config X86_VISWS
  92. bool "SGI 320/540 (Visual Workstation)"
  93. help
  94. The SGI Visual Workstation series is an IA32-based workstation
  95. based on SGI systems chips with some legacy PC hardware attached.
  96. Say Y here to create a kernel to run on the SGI 320 or 540.
  97. A kernel compiled for the Visual Workstation will not run on PCs
  98. and vice versa. See <file:Documentation/sgi-visws.txt> for details.
  99. config X86_GENERICARCH
  100. bool "Generic architecture (Summit, bigsmp, ES7000, default)"
  101. depends on SMP
  102. help
  103. This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
  104. It is intended for a generic binary kernel.
  105. config X86_ES7000
  106. bool "Support for Unisys ES7000 IA32 series"
  107. depends on SMP
  108. help
  109. Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
  110. supposed to run on an IA32-based Unisys ES7000 system.
  111. Only choose this option if you have such a system, otherwise you
  112. should say N here.
  113. endchoice
  114. config ACPI_SRAT
  115. bool
  116. default y
  117. depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
  118. config X86_SUMMIT_NUMA
  119. bool
  120. default y
  121. depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
  122. config X86_CYCLONE_TIMER
  123. bool
  124. default y
  125. depends on X86_SUMMIT || X86_GENERICARCH
  126. config ES7000_CLUSTERED_APIC
  127. bool
  128. default y
  129. depends on SMP && X86_ES7000 && MPENTIUMIII
  130. source "arch/i386/Kconfig.cpu"
  131. config HPET_TIMER
  132. bool "HPET Timer Support"
  133. help
  134. This enables the use of the HPET for the kernel's internal timer.
  135. HPET is the next generation timer replacing legacy 8254s.
  136. You can safely choose Y here. However, HPET will only be
  137. activated if the platform and the BIOS support this feature.
  138. Otherwise the 8254 will be used for timing services.
  139. Choose N to continue using the legacy 8254 timer.
  140. config HPET_EMULATE_RTC
  141. bool
  142. depends on HPET_TIMER && RTC=y
  143. default y
  144. config SMP
  145. bool "Symmetric multi-processing support"
  146. ---help---
  147. This enables support for systems with more than one CPU. If you have
  148. a system with only one CPU, like most personal computers, say N. If
  149. you have a system with more than one CPU, say Y.
  150. If you say N here, the kernel will run on single and multiprocessor
  151. machines, but will use only one CPU of a multiprocessor machine. If
  152. you say Y here, the kernel will run on many, but not all,
  153. singleprocessor machines. On a singleprocessor machine, the kernel
  154. will run faster if you say N here.
  155. Note that if you say Y here and choose architecture "586" or
  156. "Pentium" under "Processor family", the kernel will not work on 486
  157. architectures. Similarly, multiprocessor kernels for the "PPro"
  158. architecture may not work on all Pentium based boards.
  159. People using multiprocessor machines who say Y here should also say
  160. Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
  161. Management" code will be disabled if you say Y here.
  162. See also the <file:Documentation/smp.txt>,
  163. <file:Documentation/i386/IO-APIC.txt>,
  164. <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
  165. <http://www.tldp.org/docs.html#howto>.
  166. If you don't know what to do here, say N.
  167. config NR_CPUS
  168. int "Maximum number of CPUs (2-255)"
  169. range 2 255
  170. depends on SMP
  171. default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
  172. default "8"
  173. help
  174. This allows you to specify the maximum number of CPUs which this
  175. kernel will support. The maximum supported value is 255 and the
  176. minimum value which makes sense is 2.
  177. This is purely to save memory - each supported CPU adds
  178. approximately eight kilobytes to the kernel image.
  179. config SCHED_SMT
  180. bool "SMT (Hyperthreading) scheduler support"
  181. depends on SMP
  182. default off
  183. help
  184. SMT scheduler support improves the CPU scheduler's decision making
  185. when dealing with Intel Pentium 4 chips with HyperThreading at a
  186. cost of slightly increased overhead in some places. If unsure say
  187. N here.
  188. source "kernel/Kconfig.preempt"
  189. config X86_UP_APIC
  190. bool "Local APIC support on uniprocessors"
  191. depends on !SMP && !(X86_VISWS || X86_VOYAGER)
  192. help
  193. A local APIC (Advanced Programmable Interrupt Controller) is an
  194. integrated interrupt controller in the CPU. If you have a single-CPU
  195. system which has a processor with a local APIC, you can say Y here to
  196. enable and use it. If you say Y here even though your machine doesn't
  197. have a local APIC, then the kernel will still run with no slowdown at
  198. all. The local APIC supports CPU-generated self-interrupts (timer,
  199. performance counters), and the NMI watchdog which detects hard
  200. lockups.
  201. config X86_UP_IOAPIC
  202. bool "IO-APIC support on uniprocessors"
  203. depends on X86_UP_APIC
  204. help
  205. An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
  206. SMP-capable replacement for PC-style interrupt controllers. Most
  207. SMP systems and many recent uniprocessor systems have one.
  208. If you have a single-CPU system with an IO-APIC, you can say Y here
  209. to use it. If you say Y here even though your machine doesn't have
  210. an IO-APIC, then the kernel will still run with no slowdown at all.
  211. config X86_LOCAL_APIC
  212. bool
  213. depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
  214. default y
  215. config X86_IO_APIC
  216. bool
  217. depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
  218. default y
  219. config X86_VISWS_APIC
  220. bool
  221. depends on X86_VISWS
  222. default y
  223. config X86_MCE
  224. bool "Machine Check Exception"
  225. depends on !X86_VOYAGER
  226. ---help---
  227. Machine Check Exception support allows the processor to notify the
  228. kernel if it detects a problem (e.g. overheating, component failure).
  229. The action the kernel takes depends on the severity of the problem,
  230. ranging from a warning message on the console, to halting the machine.
  231. Your processor must be a Pentium or newer to support this - check the
  232. flags in /proc/cpuinfo for mce. Note that some older Pentium systems
  233. have a design flaw which leads to false MCE events - hence MCE is
  234. disabled on all P5 processors, unless explicitly enabled with "mce"
  235. as a boot argument. Similarly, if MCE is built in and creates a
  236. problem on some new non-standard machine, you can boot with "nomce"
  237. to disable it. MCE support simply ignores non-MCE processors like
  238. the 386 and 486, so nearly everyone can say Y here.
  239. config X86_MCE_NONFATAL
  240. tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
  241. depends on X86_MCE
  242. help
  243. Enabling this feature starts a timer that triggers every 5 seconds which
  244. will look at the machine check registers to see if anything happened.
  245. Non-fatal problems automatically get corrected (but still logged).
  246. Disable this if you don't want to see these messages.
  247. Seeing the messages this option prints out may be indicative of dying hardware,
  248. or out-of-spec (ie, overclocked) hardware.
  249. This option only does something on certain CPUs.
  250. (AMD Athlon/Duron and Intel Pentium 4)
  251. config X86_MCE_P4THERMAL
  252. bool "check for P4 thermal throttling interrupt."
  253. depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
  254. help
  255. Enabling this feature will cause a message to be printed when the P4
  256. enters thermal throttling.
  257. config TOSHIBA
  258. tristate "Toshiba Laptop support"
  259. ---help---
  260. This adds a driver to safely access the System Management Mode of
  261. the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
  262. not work on models with a Phoenix BIOS. The System Management Mode
  263. is used to set the BIOS and power saving options on Toshiba portables.
  264. For information on utilities to make use of this driver see the
  265. Toshiba Linux utilities web site at:
  266. <http://www.buzzard.org.uk/toshiba/>.
  267. Say Y if you intend to run this kernel on a Toshiba portable.
  268. Say N otherwise.
  269. config I8K
  270. tristate "Dell laptop support"
  271. ---help---
  272. This adds a driver to safely access the System Management Mode
  273. of the CPU on the Dell Inspiron 8000. The System Management Mode
  274. is used to read cpu temperature and cooling fan status and to
  275. control the fans on the I8K portables.
  276. This driver has been tested only on the Inspiron 8000 but it may
  277. also work with other Dell laptops. You can force loading on other
  278. models by passing the parameter `force=1' to the module. Use at
  279. your own risk.
  280. For information on utilities to make use of this driver see the
  281. I8K Linux utilities web site at:
  282. <http://people.debian.org/~dz/i8k/>
  283. Say Y if you intend to run this kernel on a Dell Inspiron 8000.
  284. Say N otherwise.
  285. config X86_REBOOTFIXUPS
  286. bool "Enable X86 board specific fixups for reboot"
  287. depends on X86
  288. default n
  289. ---help---
  290. This enables chipset and/or board specific fixups to be done
  291. in order to get reboot to work correctly. This is only needed on
  292. some combinations of hardware and BIOS. The symptom, for which
  293. this config is intended, is when reboot ends with a stalled/hung
  294. system.
  295. Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
  296. combination.
  297. Say Y if you want to enable the fixup. Currently, it's safe to
  298. enable this option even if you don't need it.
  299. Say N otherwise.
  300. config MICROCODE
  301. tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
  302. ---help---
  303. If you say Y here and also to "/dev file system support" in the
  304. 'File systems' section, you will be able to update the microcode on
  305. Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
  306. Pentium III, Pentium 4, Xeon etc. You will obviously need the
  307. actual microcode binary data itself which is not shipped with the
  308. Linux kernel.
  309. For latest news and information on obtaining all the required
  310. ingredients for this driver, check:
  311. <http://www.urbanmyth.org/microcode/>.
  312. To compile this driver as a module, choose M here: the
  313. module will be called microcode.
  314. config X86_MSR
  315. tristate "/dev/cpu/*/msr - Model-specific register support"
  316. help
  317. This device gives privileged processes access to the x86
  318. Model-Specific Registers (MSRs). It is a character device with
  319. major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
  320. MSR accesses are directed to a specific CPU on multi-processor
  321. systems.
  322. config X86_CPUID
  323. tristate "/dev/cpu/*/cpuid - CPU information support"
  324. help
  325. This device gives processes access to the x86 CPUID instruction to
  326. be executed on a specific processor. It is a character device
  327. with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
  328. /dev/cpu/31/cpuid.
  329. source "drivers/firmware/Kconfig"
  330. choice
  331. prompt "High Memory Support"
  332. default NOHIGHMEM
  333. config NOHIGHMEM
  334. bool "off"
  335. ---help---
  336. Linux can use up to 64 Gigabytes of physical memory on x86 systems.
  337. However, the address space of 32-bit x86 processors is only 4
  338. Gigabytes large. That means that, if you have a large amount of
  339. physical memory, not all of it can be "permanently mapped" by the
  340. kernel. The physical memory that's not permanently mapped is called
  341. "high memory".
  342. If you are compiling a kernel which will never run on a machine with
  343. more than 1 Gigabyte total physical RAM, answer "off" here (default
  344. choice and suitable for most users). This will result in a "3GB/1GB"
  345. split: 3GB are mapped so that each process sees a 3GB virtual memory
  346. space and the remaining part of the 4GB virtual memory space is used
  347. by the kernel to permanently map as much physical memory as
  348. possible.
  349. If the machine has between 1 and 4 Gigabytes physical RAM, then
  350. answer "4GB" here.
  351. If more than 4 Gigabytes is used then answer "64GB" here. This
  352. selection turns Intel PAE (Physical Address Extension) mode on.
  353. PAE implements 3-level paging on IA32 processors. PAE is fully
  354. supported by Linux, PAE mode is implemented on all recent Intel
  355. processors (Pentium Pro and better). NOTE: If you say "64GB" here,
  356. then the kernel will not boot on CPUs that don't support PAE!
  357. The actual amount of total physical memory will either be
  358. auto detected or can be forced by using a kernel command line option
  359. such as "mem=256M". (Try "man bootparam" or see the documentation of
  360. your boot loader (lilo or loadlin) about how to pass options to the
  361. kernel at boot time.)
  362. If unsure, say "off".
  363. config HIGHMEM4G
  364. bool "4GB"
  365. help
  366. Select this if you have a 32-bit processor and between 1 and 4
  367. gigabytes of physical RAM.
  368. config HIGHMEM64G
  369. bool "64GB"
  370. help
  371. Select this if you have a 32-bit processor and more than 4
  372. gigabytes of physical RAM.
  373. endchoice
  374. config HIGHMEM
  375. bool
  376. depends on HIGHMEM64G || HIGHMEM4G
  377. default y
  378. config X86_PAE
  379. bool
  380. depends on HIGHMEM64G
  381. default y
  382. # Common NUMA Features
  383. config NUMA
  384. bool "Numa Memory Allocation and Scheduler Support"
  385. depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
  386. default n if X86_PC
  387. default y if (X86_NUMAQ || X86_SUMMIT)
  388. # Need comments to help the hapless user trying to turn on NUMA support
  389. comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
  390. depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
  391. comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
  392. depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
  393. config HAVE_ARCH_BOOTMEM_NODE
  394. bool
  395. depends on NUMA
  396. default y
  397. config ARCH_HAVE_MEMORY_PRESENT
  398. bool
  399. depends on DISCONTIGMEM
  400. default y
  401. config NEED_NODE_MEMMAP_SIZE
  402. bool
  403. depends on DISCONTIGMEM || SPARSEMEM
  404. default y
  405. config HAVE_ARCH_ALLOC_REMAP
  406. bool
  407. depends on NUMA
  408. default y
  409. config ARCH_FLATMEM_ENABLE
  410. def_bool y
  411. depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
  412. config ARCH_DISCONTIGMEM_ENABLE
  413. def_bool y
  414. depends on NUMA
  415. config ARCH_DISCONTIGMEM_DEFAULT
  416. def_bool y
  417. depends on NUMA
  418. config ARCH_SPARSEMEM_ENABLE
  419. def_bool y
  420. depends on (NUMA || (X86_PC && EXPERIMENTAL))
  421. select SPARSEMEM_STATIC
  422. config ARCH_SELECT_MEMORY_MODEL
  423. def_bool y
  424. depends on ARCH_SPARSEMEM_ENABLE
  425. source "mm/Kconfig"
  426. config HAVE_ARCH_EARLY_PFN_TO_NID
  427. bool
  428. default y
  429. depends on NUMA
  430. config HIGHPTE
  431. bool "Allocate 3rd-level pagetables from highmem"
  432. depends on HIGHMEM4G || HIGHMEM64G
  433. help
  434. The VM uses one page table entry for each page of physical memory.
  435. For systems with a lot of RAM, this can be wasteful of precious
  436. low memory. Setting this option will put user-space page table
  437. entries in high memory.
  438. config MATH_EMULATION
  439. bool "Math emulation"
  440. ---help---
  441. Linux can emulate a math coprocessor (used for floating point
  442. operations) if you don't have one. 486DX and Pentium processors have
  443. a math coprocessor built in, 486SX and 386 do not, unless you added
  444. a 487DX or 387, respectively. (The messages during boot time can
  445. give you some hints here ["man dmesg"].) Everyone needs either a
  446. coprocessor or this emulation.
  447. If you don't have a math coprocessor, you need to say Y here; if you
  448. say Y here even though you have a coprocessor, the coprocessor will
  449. be used nevertheless. (This behavior can be changed with the kernel
  450. command line option "no387", which comes handy if your coprocessor
  451. is broken. Try "man bootparam" or see the documentation of your boot
  452. loader (lilo or loadlin) about how to pass options to the kernel at
  453. boot time.) This means that it is a good idea to say Y here if you
  454. intend to use this kernel on different machines.
  455. More information about the internals of the Linux math coprocessor
  456. emulation can be found in <file:arch/i386/math-emu/README>.
  457. If you are not sure, say Y; apart from resulting in a 66 KB bigger
  458. kernel, it won't hurt.
  459. config MTRR
  460. bool "MTRR (Memory Type Range Register) support"
  461. ---help---
  462. On Intel P6 family processors (Pentium Pro, Pentium II and later)
  463. the Memory Type Range Registers (MTRRs) may be used to control
  464. processor access to memory ranges. This is most useful if you have
  465. a video (VGA) card on a PCI or AGP bus. Enabling write-combining
  466. allows bus write transfers to be combined into a larger transfer
  467. before bursting over the PCI/AGP bus. This can increase performance
  468. of image write operations 2.5 times or more. Saying Y here creates a
  469. /proc/mtrr file which may be used to manipulate your processor's
  470. MTRRs. Typically the X server should use this.
  471. This code has a reasonably generic interface so that similar
  472. control registers on other processors can be easily supported
  473. as well:
  474. The Cyrix 6x86, 6x86MX and M II processors have Address Range
  475. Registers (ARRs) which provide a similar functionality to MTRRs. For
  476. these, the ARRs are used to emulate the MTRRs.
  477. The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
  478. MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
  479. write-combining. All of these processors are supported by this code
  480. and it makes sense to say Y here if you have one of them.
  481. Saying Y here also fixes a problem with buggy SMP BIOSes which only
  482. set the MTRRs for the boot CPU and not for the secondary CPUs. This
  483. can lead to all sorts of problems, so it's good to say Y here.
  484. You can safely say Y even if your machine doesn't have MTRRs, you'll
  485. just add about 9 KB to your kernel.
  486. See <file:Documentation/mtrr.txt> for more information.
  487. config EFI
  488. bool "Boot from EFI support (EXPERIMENTAL)"
  489. depends on ACPI
  490. default n
  491. ---help---
  492. This enables the the kernel to boot on EFI platforms using
  493. system configuration information passed to it from the firmware.
  494. This also enables the kernel to use any EFI runtime services that are
  495. available (such as the EFI variable services).
  496. This option is only useful on systems that have EFI firmware
  497. and will result in a kernel image that is ~8k larger. In addition,
  498. you must use the latest ELILO loader available at
  499. <http://elilo.sourceforge.net> in order to take advantage of
  500. kernel initialization using EFI information (neither GRUB nor LILO know
  501. anything about EFI). However, even with this option, the resultant
  502. kernel should continue to boot on existing non-EFI platforms.
  503. config IRQBALANCE
  504. bool "Enable kernel irq balancing"
  505. depends on SMP && X86_IO_APIC
  506. default y
  507. help
  508. The default yes will allow the kernel to do irq load balancing.
  509. Saying no will keep the kernel from doing irq load balancing.
  510. # turning this on wastes a bunch of space.
  511. # Summit needs it only when NUMA is on
  512. config BOOT_IOREMAP
  513. bool
  514. depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
  515. default y
  516. config REGPARM
  517. bool "Use register arguments (EXPERIMENTAL)"
  518. depends on EXPERIMENTAL
  519. default n
  520. help
  521. Compile the kernel with -mregparm=3. This uses a different ABI
  522. and passes the first three arguments of a function call in registers.
  523. This will probably break binary only modules.
  524. config SECCOMP
  525. bool "Enable seccomp to safely compute untrusted bytecode"
  526. depends on PROC_FS
  527. default y
  528. help
  529. This kernel feature is useful for number crunching applications
  530. that may need to compute untrusted bytecode during their
  531. execution. By using pipes or other transports made available to
  532. the process as file descriptors supporting the read/write
  533. syscalls, it's possible to isolate those applications in
  534. their own address space using seccomp. Once seccomp is
  535. enabled via /proc/<pid>/seccomp, it cannot be disabled
  536. and the task is only allowed to execute a few safe syscalls
  537. defined by each seccomp mode.
  538. If unsure, say Y. Only embedded should say N here.
  539. source kernel/Kconfig.hz
  540. config KEXEC
  541. bool "kexec system call (EXPERIMENTAL)"
  542. depends on EXPERIMENTAL
  543. help
  544. kexec is a system call that implements the ability to shutdown your
  545. current kernel, and to start another kernel. It is like a reboot
  546. but it is indepedent of the system firmware. And like a reboot
  547. you can start any kernel with it, not just Linux.
  548. The name comes from the similiarity to the exec system call.
  549. It is an ongoing process to be certain the hardware in a machine
  550. is properly shutdown, so do not be surprised if this code does not
  551. initially work for you. It may help to enable device hotplugging
  552. support. As of this writing the exact hardware interface is
  553. strongly in flux, so no good recommendation can be made.
  554. config CRASH_DUMP
  555. bool "kernel crash dumps (EXPERIMENTAL)"
  556. depends on EXPERIMENTAL
  557. depends on HIGHMEM
  558. help
  559. Generate crash dump after being started by kexec.
  560. config PHYSICAL_START
  561. hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
  562. default "0x1000000" if CRASH_DUMP
  563. default "0x100000"
  564. help
  565. This gives the physical address where the kernel is loaded. Normally
  566. for regular kernels this value is 0x100000 (1MB). But in the case
  567. of kexec on panic the fail safe kernel needs to run at a different
  568. address than the panic-ed kernel. This option is used to set the load
  569. address for kernels used to capture crash dump on being kexec'ed
  570. after panic. The default value for crash dump kernels is
  571. 0x1000000 (16MB). This can also be set based on the "X" value as
  572. specified in the "crashkernel=YM@XM" command line boot parameter
  573. passed to the panic-ed kernel. Typically this parameter is set as
  574. crashkernel=64M@16M. Please take a look at
  575. Documentation/kdump/kdump.txt for more details about crash dumps.
  576. Don't change this unless you know what you are doing.
  577. config HOTPLUG_CPU
  578. bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
  579. depends on SMP && HOTPLUG && EXPERIMENTAL
  580. ---help---
  581. Say Y here to experiment with turning CPUs off and on. CPUs
  582. can be controlled through /sys/devices/system/cpu.
  583. Say N.
  584. endmenu
  585. menu "Power management options (ACPI, APM)"
  586. depends on !X86_VOYAGER
  587. source kernel/power/Kconfig
  588. source "drivers/acpi/Kconfig"
  589. menu "APM (Advanced Power Management) BIOS Support"
  590. depends on PM && !X86_VISWS
  591. config APM
  592. tristate "APM (Advanced Power Management) BIOS support"
  593. depends on PM
  594. ---help---
  595. APM is a BIOS specification for saving power using several different
  596. techniques. This is mostly useful for battery powered laptops with
  597. APM compliant BIOSes. If you say Y here, the system time will be
  598. reset after a RESUME operation, the /proc/apm device will provide
  599. battery status information, and user-space programs will receive
  600. notification of APM "events" (e.g. battery status change).
  601. If you select "Y" here, you can disable actual use of the APM
  602. BIOS by passing the "apm=off" option to the kernel at boot time.
  603. Note that the APM support is almost completely disabled for
  604. machines with more than one CPU.
  605. In order to use APM, you will need supporting software. For location
  606. and more information, read <file:Documentation/pm.txt> and the
  607. Battery Powered Linux mini-HOWTO, available from
  608. <http://www.tldp.org/docs.html#howto>.
  609. This driver does not spin down disk drives (see the hdparm(8)
  610. manpage ("man 8 hdparm") for that), and it doesn't turn off
  611. VESA-compliant "green" monitors.
  612. This driver does not support the TI 4000M TravelMate and the ACER
  613. 486/DX4/75 because they don't have compliant BIOSes. Many "green"
  614. desktop machines also don't have compliant BIOSes, and this driver
  615. may cause those machines to panic during the boot phase.
  616. Generally, if you don't have a battery in your machine, there isn't
  617. much point in using this driver and you should say N. If you get
  618. random kernel OOPSes or reboots that don't seem to be related to
  619. anything, try disabling/enabling this option (or disabling/enabling
  620. APM in your BIOS).
  621. Some other things you should try when experiencing seemingly random,
  622. "weird" problems:
  623. 1) make sure that you have enough swap space and that it is
  624. enabled.
  625. 2) pass the "no-hlt" option to the kernel
  626. 3) switch on floating point emulation in the kernel and pass
  627. the "no387" option to the kernel
  628. 4) pass the "floppy=nodma" option to the kernel
  629. 5) pass the "mem=4M" option to the kernel (thereby disabling
  630. all but the first 4 MB of RAM)
  631. 6) make sure that the CPU is not over clocked.
  632. 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
  633. 8) disable the cache from your BIOS settings
  634. 9) install a fan for the video card or exchange video RAM
  635. 10) install a better fan for the CPU
  636. 11) exchange RAM chips
  637. 12) exchange the motherboard.
  638. To compile this driver as a module, choose M here: the
  639. module will be called apm.
  640. config APM_IGNORE_USER_SUSPEND
  641. bool "Ignore USER SUSPEND"
  642. depends on APM
  643. help
  644. This option will ignore USER SUSPEND requests. On machines with a
  645. compliant APM BIOS, you want to say N. However, on the NEC Versa M
  646. series notebooks, it is necessary to say Y because of a BIOS bug.
  647. config APM_DO_ENABLE
  648. bool "Enable PM at boot time"
  649. depends on APM
  650. ---help---
  651. Enable APM features at boot time. From page 36 of the APM BIOS
  652. specification: "When disabled, the APM BIOS does not automatically
  653. power manage devices, enter the Standby State, enter the Suspend
  654. State, or take power saving steps in response to CPU Idle calls."
  655. This driver will make CPU Idle calls when Linux is idle (unless this
  656. feature is turned off -- see "Do CPU IDLE calls", below). This
  657. should always save battery power, but more complicated APM features
  658. will be dependent on your BIOS implementation. You may need to turn
  659. this option off if your computer hangs at boot time when using APM
  660. support, or if it beeps continuously instead of suspending. Turn
  661. this off if you have a NEC UltraLite Versa 33/C or a Toshiba
  662. T400CDT. This is off by default since most machines do fine without
  663. this feature.
  664. config APM_CPU_IDLE
  665. bool "Make CPU Idle calls when idle"
  666. depends on APM
  667. help
  668. Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
  669. On some machines, this can activate improved power savings, such as
  670. a slowed CPU clock rate, when the machine is idle. These idle calls
  671. are made after the idle loop has run for some length of time (e.g.,
  672. 333 mS). On some machines, this will cause a hang at boot time or
  673. whenever the CPU becomes idle. (On machines with more than one CPU,
  674. this option does nothing.)
  675. config APM_DISPLAY_BLANK
  676. bool "Enable console blanking using APM"
  677. depends on APM
  678. help
  679. Enable console blanking using the APM. Some laptops can use this to
  680. turn off the LCD backlight when the screen blanker of the Linux
  681. virtual console blanks the screen. Note that this is only used by
  682. the virtual console screen blanker, and won't turn off the backlight
  683. when using the X Window system. This also doesn't have anything to
  684. do with your VESA-compliant power-saving monitor. Further, this
  685. option doesn't work for all laptops -- it might not turn off your
  686. backlight at all, or it might print a lot of errors to the console,
  687. especially if you are using gpm.
  688. config APM_RTC_IS_GMT
  689. bool "RTC stores time in GMT"
  690. depends on APM
  691. help
  692. Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
  693. stores the time in GMT (Greenwich Mean Time). Say N if your RTC
  694. stores localtime.
  695. It is in fact recommended to store GMT in your RTC, because then you
  696. don't have to worry about daylight savings time changes. The only
  697. reason not to use GMT in your RTC is if you also run a broken OS
  698. that doesn't understand GMT.
  699. config APM_ALLOW_INTS
  700. bool "Allow interrupts during APM BIOS calls"
  701. depends on APM
  702. help
  703. Normally we disable external interrupts while we are making calls to
  704. the APM BIOS as a measure to lessen the effects of a badly behaving
  705. BIOS implementation. The BIOS should reenable interrupts if it
  706. needs to. Unfortunately, some BIOSes do not -- especially those in
  707. many of the newer IBM Thinkpads. If you experience hangs when you
  708. suspend, try setting this to Y. Otherwise, say N.
  709. config APM_REAL_MODE_POWER_OFF
  710. bool "Use real mode APM BIOS call to power off"
  711. depends on APM
  712. help
  713. Use real mode APM BIOS calls to switch off the computer. This is
  714. a work-around for a number of buggy BIOSes. Switch this option on if
  715. your computer crashes instead of powering off properly.
  716. endmenu
  717. source "arch/i386/kernel/cpu/cpufreq/Kconfig"
  718. endmenu
  719. menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
  720. config PCI
  721. bool "PCI support" if !X86_VISWS
  722. depends on !X86_VOYAGER
  723. default y if X86_VISWS
  724. help
  725. Find out whether you have a PCI motherboard. PCI is the name of a
  726. bus system, i.e. the way the CPU talks to the other stuff inside
  727. your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
  728. VESA. If you have PCI, say Y, otherwise N.
  729. The PCI-HOWTO, available from
  730. <http://www.tldp.org/docs.html#howto>, contains valuable
  731. information about which PCI hardware does work under Linux and which
  732. doesn't.
  733. choice
  734. prompt "PCI access mode"
  735. depends on PCI && !X86_VISWS
  736. default PCI_GOANY
  737. ---help---
  738. On PCI systems, the BIOS can be used to detect the PCI devices and
  739. determine their configuration. However, some old PCI motherboards
  740. have BIOS bugs and may crash if this is done. Also, some embedded
  741. PCI-based systems don't have any BIOS at all. Linux can also try to
  742. detect the PCI hardware directly without using the BIOS.
  743. With this option, you can specify how Linux should detect the
  744. PCI devices. If you choose "BIOS", the BIOS will be used,
  745. if you choose "Direct", the BIOS won't be used, and if you
  746. choose "MMConfig", then PCI Express MMCONFIG will be used.
  747. If you choose "Any", the kernel will try MMCONFIG, then the
  748. direct access method and falls back to the BIOS if that doesn't
  749. work. If unsure, go with the default, which is "Any".
  750. config PCI_GOBIOS
  751. bool "BIOS"
  752. config PCI_GOMMCONFIG
  753. bool "MMConfig"
  754. config PCI_GODIRECT
  755. bool "Direct"
  756. config PCI_GOANY
  757. bool "Any"
  758. endchoice
  759. config PCI_BIOS
  760. bool
  761. depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
  762. default y
  763. config PCI_DIRECT
  764. bool
  765. depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
  766. default y
  767. config PCI_MMCONFIG
  768. bool
  769. depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
  770. default y
  771. source "drivers/pci/pcie/Kconfig"
  772. source "drivers/pci/Kconfig"
  773. config ISA_DMA_API
  774. bool
  775. default y
  776. config ISA
  777. bool "ISA support"
  778. depends on !(X86_VOYAGER || X86_VISWS)
  779. help
  780. Find out whether you have ISA slots on your motherboard. ISA is the
  781. name of a bus system, i.e. the way the CPU talks to the other stuff
  782. inside your box. Other bus systems are PCI, EISA, MicroChannel
  783. (MCA) or VESA. ISA is an older system, now being displaced by PCI;
  784. newer boards don't support it. If you have ISA, say Y, otherwise N.
  785. config EISA
  786. bool "EISA support"
  787. depends on ISA
  788. ---help---
  789. The Extended Industry Standard Architecture (EISA) bus was
  790. developed as an open alternative to the IBM MicroChannel bus.
  791. The EISA bus provided some of the features of the IBM MicroChannel
  792. bus while maintaining backward compatibility with cards made for
  793. the older ISA bus. The EISA bus saw limited use between 1988 and
  794. 1995 when it was made obsolete by the PCI bus.
  795. Say Y here if you are building a kernel for an EISA-based machine.
  796. Otherwise, say N.
  797. source "drivers/eisa/Kconfig"
  798. config MCA
  799. bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
  800. default y if X86_VOYAGER
  801. help
  802. MicroChannel Architecture is found in some IBM PS/2 machines and
  803. laptops. It is a bus system similar to PCI or ISA. See
  804. <file:Documentation/mca.txt> (and especially the web page given
  805. there) before attempting to build an MCA bus kernel.
  806. source "drivers/mca/Kconfig"
  807. config SCx200
  808. tristate "NatSemi SCx200 support"
  809. depends on !X86_VOYAGER
  810. help
  811. This provides basic support for the National Semiconductor SCx200
  812. processor. Right now this is just a driver for the GPIO pins.
  813. If you don't know what to do here, say N.
  814. This support is also available as a module. If compiled as a
  815. module, it will be called scx200.
  816. source "drivers/pcmcia/Kconfig"
  817. source "drivers/pci/hotplug/Kconfig"
  818. endmenu
  819. menu "Executable file formats"
  820. source "fs/Kconfig.binfmt"
  821. endmenu
  822. source "net/Kconfig"
  823. source "drivers/Kconfig"
  824. source "fs/Kconfig"
  825. menu "Instrumentation Support"
  826. depends on EXPERIMENTAL
  827. source "arch/i386/oprofile/Kconfig"
  828. config KPROBES
  829. bool "Kprobes (EXPERIMENTAL)"
  830. help
  831. Kprobes allows you to trap at almost any kernel address and
  832. execute a callback function. register_kprobe() establishes
  833. a probepoint and specifies the callback. Kprobes is useful
  834. for kernel debugging, non-intrusive instrumentation and testing.
  835. If in doubt, say "N".
  836. endmenu
  837. source "arch/i386/Kconfig.debug"
  838. source "security/Kconfig"
  839. source "crypto/Kconfig"
  840. source "lib/Kconfig"
  841. #
  842. # Use the generic interrupt handling code in kernel/irq/:
  843. #
  844. config GENERIC_HARDIRQS
  845. bool
  846. default y
  847. config GENERIC_IRQ_PROBE
  848. bool
  849. default y
  850. config GENERIC_PENDING_IRQ
  851. bool
  852. depends on GENERIC_HARDIRQS && SMP
  853. default y
  854. config X86_SMP
  855. bool
  856. depends on SMP && !X86_VOYAGER
  857. default y
  858. config X86_HT
  859. bool
  860. depends on SMP && !(X86_VISWS || X86_VOYAGER)
  861. default y
  862. config X86_BIOS_REBOOT
  863. bool
  864. depends on !(X86_VISWS || X86_VOYAGER)
  865. default y
  866. config X86_TRAMPOLINE
  867. bool
  868. depends on X86_SMP || (X86_VOYAGER && SMP)
  869. default y
  870. config KTIME_SCALAR
  871. bool
  872. default y