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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#
2# For a description of the syntax of this configuration file,
3# see Documentation/kbuild/kconfig-language.txt.
4#
5
6mainmenu "Linux Kernel Configuration"
7
Brian Gerst0d078f62005-10-30 14:59:20 -08008config X86_32
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 bool
10 default y
11 help
12 This is Linux's home port. Linux was originally native to the Intel
13 386, and runs on all the later x86 processors including the Intel
14 486, 586, Pentiums, and various instruction-set-compatible chips by
15 AMD, Cyrix, and others.
16
john stultz6f84fa22006-06-26 00:25:11 -070017config GENERIC_TIME
18 bool
19 default y
20
Benjamin LaHaise52fdd082005-09-03 15:56:52 -070021config SEMAPHORE_SLEEPERS
22 bool
23 default y
24
Brian Gerst0d078f62005-10-30 14:59:20 -080025config X86
26 bool
27 default y
28
Linus Torvalds1da177e2005-04-16 15:20:36 -070029config MMU
30 bool
31 default y
32
33config SBUS
34 bool
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036config GENERIC_ISA_DMA
37 bool
38 default y
39
40config GENERIC_IOMAP
41 bool
42 default y
43
Akinobu Mita1cc2b992006-03-26 01:39:24 -080044config GENERIC_HWEIGHT
45 bool
46 default y
47
viro@ZenIV.linux.org.uka08b6b72005-09-06 01:48:42 +010048config ARCH_MAY_HAVE_PC_FDC
49 bool
50 default y
51
Andi Kleene9928672006-01-11 22:43:33 +010052config DMI
53 bool
54 default y
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056source "init/Kconfig"
57
58menu "Processor type and features"
59
Adrian Bunkedd711f2006-04-10 22:53:14 -070060config SMP
61 bool "Symmetric multi-processing support"
62 ---help---
63 This enables support for systems with more than one CPU. If you have
64 a system with only one CPU, like most personal computers, say N. If
65 you have a system with more than one CPU, say Y.
66
67 If you say N here, the kernel will run on single and multiprocessor
68 machines, but will use only one CPU of a multiprocessor machine. If
69 you say Y here, the kernel will run on many, but not all,
70 singleprocessor machines. On a singleprocessor machine, the kernel
71 will run faster if you say N here.
72
73 Note that if you say Y here and choose architecture "586" or
74 "Pentium" under "Processor family", the kernel will not work on 486
75 architectures. Similarly, multiprocessor kernels for the "PPro"
76 architecture may not work on all Pentium based boards.
77
78 People using multiprocessor machines who say Y here should also say
79 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
80 Management" code will be disabled if you say Y here.
81
82 See also the <file:Documentation/smp.txt>,
83 <file:Documentation/i386/IO-APIC.txt>,
84 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
85 <http://www.tldp.org/docs.html#howto>.
86
87 If you don't know what to do here, say N.
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089choice
90 prompt "Subarchitecture Type"
91 default X86_PC
92
93config X86_PC
94 bool "PC-compatible"
95 help
96 Choose this option if your computer is a standard PC or compatible.
97
98config X86_ELAN
99 bool "AMD Elan"
100 help
101 Select this for an AMD Elan processor.
102
103 Do not use this option for K6/Athlon/Opteron processors!
104
105 If unsure, choose "PC-compatible" instead.
106
107config X86_VOYAGER
108 bool "Voyager (NCR)"
109 help
110 Voyager is an MCA-based 32-way capable SMP architecture proprietary
111 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
112
113 *** WARNING ***
114
115 If you do not specifically know you have a Voyager based machine,
116 say N here, otherwise the kernel you build will not be bootable.
117
118config X86_NUMAQ
119 bool "NUMAQ (IBM/Sequent)"
Adrian Bunk905c3992006-03-23 02:59:55 -0800120 select SMP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 select NUMA
122 help
123 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
124 multiquad box. This changes the way that processors are bootstrapped,
125 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
126 You will need a new lynxer.elf file to flash your firmware with - send
127 email to <Martin.Bligh@us.ibm.com>.
128
129config X86_SUMMIT
130 bool "Summit/EXA (IBM x440)"
131 depends on SMP
132 help
133 This option is needed for IBM systems that use the Summit/EXA chipset.
134 In particular, it is needed for the x440.
135
136 If you don't have one of these computers, you should say N here.
137
138config X86_BIGSMP
139 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
140 depends on SMP
141 help
142 This option is needed for the systems that have more than 8 CPUs
143 and if the system is not of any sub-arch type above.
144
145 If you don't have such a system, you should say N here.
146
147config X86_VISWS
148 bool "SGI 320/540 (Visual Workstation)"
149 help
150 The SGI Visual Workstation series is an IA32-based workstation
151 based on SGI systems chips with some legacy PC hardware attached.
152
153 Say Y here to create a kernel to run on the SGI 320 or 540.
154
155 A kernel compiled for the Visual Workstation will not run on PCs
156 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
157
158config X86_GENERICARCH
159 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
160 depends on SMP
161 help
162 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
163 It is intended for a generic binary kernel.
164
165config X86_ES7000
166 bool "Support for Unisys ES7000 IA32 series"
167 depends on SMP
168 help
169 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
170 supposed to run on an IA32-based Unisys ES7000 system.
171 Only choose this option if you have such a system, otherwise you
172 should say N here.
173
174endchoice
175
176config ACPI_SRAT
177 bool
178 default y
179 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
Yasunori Goto762834e2006-06-23 02:03:19 -0700180 select ACPI_NUMA
181
182config HAVE_ARCH_PARSE_SRAT
183 bool
184 default y
185 depends on ACPI_SRAT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
187config X86_SUMMIT_NUMA
188 bool
189 default y
190 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
191
192config X86_CYCLONE_TIMER
193 bool
194 default y
195 depends on X86_SUMMIT || X86_GENERICARCH
196
197config ES7000_CLUSTERED_APIC
198 bool
199 default y
200 depends on SMP && X86_ES7000 && MPENTIUMIII
201
Paolo 'Blaisorblade' Giarrusso96d55b82005-10-30 15:00:07 -0800202source "arch/i386/Kconfig.cpu"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204config HPET_TIMER
205 bool "HPET Timer Support"
206 help
207 This enables the use of the HPET for the kernel's internal timer.
208 HPET is the next generation timer replacing legacy 8254s.
209 You can safely choose Y here. However, HPET will only be
210 activated if the platform and the BIOS support this feature.
211 Otherwise the 8254 will be used for timing services.
212
213 Choose N to continue using the legacy 8254 timer.
214
215config HPET_EMULATE_RTC
Venkatesh Pallipadic91096d2005-08-04 15:36:10 -0700216 bool
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 depends on HPET_TIMER && RTC=y
Venkatesh Pallipadic91096d2005-08-04 15:36:10 -0700218 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220config NR_CPUS
221 int "Maximum number of CPUs (2-255)"
222 range 2 255
223 depends on SMP
224 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
225 default "8"
226 help
227 This allows you to specify the maximum number of CPUs which this
228 kernel will support. The maximum supported value is 255 and the
229 minimum value which makes sense is 2.
230
231 This is purely to save memory - each supported CPU adds
232 approximately eight kilobytes to the kernel image.
233
234config SCHED_SMT
235 bool "SMT (Hyperthreading) scheduler support"
236 depends on SMP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 help
238 SMT scheduler support improves the CPU scheduler's decision making
239 when dealing with Intel Pentium 4 chips with HyperThreading at a
240 cost of slightly increased overhead in some places. If unsure say
241 N here.
242
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -0800243config SCHED_MC
244 bool "Multi-core scheduler support"
245 depends on SMP
246 default y
247 help
248 Multi-core scheduler support improves the CPU scheduler's decision
249 making when dealing with multi-core CPU chips at a cost of slightly
250 increased overhead in some places. If unsure say N here.
251
Ingo Molnarcc19ca82005-06-25 14:57:36 -0700252source "kernel/Kconfig.preempt"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254config X86_UP_APIC
255 bool "Local APIC support on uniprocessors"
256 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
257 help
258 A local APIC (Advanced Programmable Interrupt Controller) is an
259 integrated interrupt controller in the CPU. If you have a single-CPU
260 system which has a processor with a local APIC, you can say Y here to
261 enable and use it. If you say Y here even though your machine doesn't
262 have a local APIC, then the kernel will still run with no slowdown at
263 all. The local APIC supports CPU-generated self-interrupts (timer,
264 performance counters), and the NMI watchdog which detects hard
265 lockups.
266
267config X86_UP_IOAPIC
268 bool "IO-APIC support on uniprocessors"
269 depends on X86_UP_APIC
270 help
271 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
272 SMP-capable replacement for PC-style interrupt controllers. Most
273 SMP systems and many recent uniprocessor systems have one.
274
275 If you have a single-CPU system with an IO-APIC, you can say Y here
276 to use it. If you say Y here even though your machine doesn't have
277 an IO-APIC, then the kernel will still run with no slowdown at all.
278
279config X86_LOCAL_APIC
280 bool
281 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
282 default y
283
284config X86_IO_APIC
285 bool
286 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
287 default y
288
289config X86_VISWS_APIC
290 bool
291 depends on X86_VISWS
292 default y
293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294config X86_MCE
295 bool "Machine Check Exception"
296 depends on !X86_VOYAGER
297 ---help---
298 Machine Check Exception support allows the processor to notify the
299 kernel if it detects a problem (e.g. overheating, component failure).
300 The action the kernel takes depends on the severity of the problem,
301 ranging from a warning message on the console, to halting the machine.
302 Your processor must be a Pentium or newer to support this - check the
303 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
304 have a design flaw which leads to false MCE events - hence MCE is
305 disabled on all P5 processors, unless explicitly enabled with "mce"
306 as a boot argument. Similarly, if MCE is built in and creates a
307 problem on some new non-standard machine, you can boot with "nomce"
308 to disable it. MCE support simply ignores non-MCE processors like
309 the 386 and 486, so nearly everyone can say Y here.
310
311config X86_MCE_NONFATAL
312 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
313 depends on X86_MCE
314 help
315 Enabling this feature starts a timer that triggers every 5 seconds which
316 will look at the machine check registers to see if anything happened.
317 Non-fatal problems automatically get corrected (but still logged).
318 Disable this if you don't want to see these messages.
319 Seeing the messages this option prints out may be indicative of dying hardware,
320 or out-of-spec (ie, overclocked) hardware.
321 This option only does something on certain CPUs.
322 (AMD Athlon/Duron and Intel Pentium 4)
323
324config X86_MCE_P4THERMAL
325 bool "check for P4 thermal throttling interrupt."
326 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
327 help
328 Enabling this feature will cause a message to be printed when the P4
329 enters thermal throttling.
330
Andi Kleenc38bfdc2006-06-26 13:58:44 +0200331config VM86
332 default y
333 bool "Enable VM86 support" if EMBEDDED
334 help
335 This option is required by programs like DOSEMU to run 16-bit legacy
336 code on X86 processors. It also may be needed by software like
337 XFree86 to initialize some video cards via BIOS. Disabling this
338 option saves about 6k.
339
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340config TOSHIBA
341 tristate "Toshiba Laptop support"
342 ---help---
343 This adds a driver to safely access the System Management Mode of
344 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
345 not work on models with a Phoenix BIOS. The System Management Mode
346 is used to set the BIOS and power saving options on Toshiba portables.
347
348 For information on utilities to make use of this driver see the
349 Toshiba Linux utilities web site at:
350 <http://www.buzzard.org.uk/toshiba/>.
351
352 Say Y if you intend to run this kernel on a Toshiba portable.
353 Say N otherwise.
354
355config I8K
356 tristate "Dell laptop support"
357 ---help---
358 This adds a driver to safely access the System Management Mode
359 of the CPU on the Dell Inspiron 8000. The System Management Mode
360 is used to read cpu temperature and cooling fan status and to
361 control the fans on the I8K portables.
362
363 This driver has been tested only on the Inspiron 8000 but it may
364 also work with other Dell laptops. You can force loading on other
365 models by passing the parameter `force=1' to the module. Use at
366 your own risk.
367
368 For information on utilities to make use of this driver see the
369 I8K Linux utilities web site at:
370 <http://people.debian.org/~dz/i8k/>
371
372 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
373 Say N otherwise.
374
Jaya Kumara2f7c352005-05-01 08:58:49 -0700375config X86_REBOOTFIXUPS
376 bool "Enable X86 board specific fixups for reboot"
377 depends on X86
378 default n
379 ---help---
380 This enables chipset and/or board specific fixups to be done
381 in order to get reboot to work correctly. This is only needed on
382 some combinations of hardware and BIOS. The symptom, for which
383 this config is intended, is when reboot ends with a stalled/hung
384 system.
385
386 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
387 combination.
388
389 Say Y if you want to enable the fixup. Currently, it's safe to
390 enable this option even if you don't need it.
391 Say N otherwise.
392
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393config MICROCODE
394 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
395 ---help---
396 If you say Y here and also to "/dev file system support" in the
397 'File systems' section, you will be able to update the microcode on
398 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
399 Pentium III, Pentium 4, Xeon etc. You will obviously need the
400 actual microcode binary data itself which is not shipped with the
401 Linux kernel.
402
403 For latest news and information on obtaining all the required
404 ingredients for this driver, check:
405 <http://www.urbanmyth.org/microcode/>.
406
407 To compile this driver as a module, choose M here: the
408 module will be called microcode.
409
410config X86_MSR
411 tristate "/dev/cpu/*/msr - Model-specific register support"
412 help
413 This device gives privileged processes access to the x86
414 Model-Specific Registers (MSRs). It is a character device with
415 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
416 MSR accesses are directed to a specific CPU on multi-processor
417 systems.
418
419config X86_CPUID
420 tristate "/dev/cpu/*/cpuid - CPU information support"
421 help
422 This device gives processes access to the x86 CPUID instruction to
423 be executed on a specific processor. It is a character device
424 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
425 /dev/cpu/31/cpuid.
426
427source "drivers/firmware/Kconfig"
428
429choice
430 prompt "High Memory Support"
431 default NOHIGHMEM
432
433config NOHIGHMEM
434 bool "off"
Adrian Bunk905c3992006-03-23 02:59:55 -0800435 depends on !X86_NUMAQ
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 ---help---
437 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
438 However, the address space of 32-bit x86 processors is only 4
439 Gigabytes large. That means that, if you have a large amount of
440 physical memory, not all of it can be "permanently mapped" by the
441 kernel. The physical memory that's not permanently mapped is called
442 "high memory".
443
444 If you are compiling a kernel which will never run on a machine with
445 more than 1 Gigabyte total physical RAM, answer "off" here (default
446 choice and suitable for most users). This will result in a "3GB/1GB"
447 split: 3GB are mapped so that each process sees a 3GB virtual memory
448 space and the remaining part of the 4GB virtual memory space is used
449 by the kernel to permanently map as much physical memory as
450 possible.
451
452 If the machine has between 1 and 4 Gigabytes physical RAM, then
453 answer "4GB" here.
454
455 If more than 4 Gigabytes is used then answer "64GB" here. This
456 selection turns Intel PAE (Physical Address Extension) mode on.
457 PAE implements 3-level paging on IA32 processors. PAE is fully
458 supported by Linux, PAE mode is implemented on all recent Intel
459 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
460 then the kernel will not boot on CPUs that don't support PAE!
461
462 The actual amount of total physical memory will either be
463 auto detected or can be forced by using a kernel command line option
464 such as "mem=256M". (Try "man bootparam" or see the documentation of
465 your boot loader (lilo or loadlin) about how to pass options to the
466 kernel at boot time.)
467
468 If unsure, say "off".
469
470config HIGHMEM4G
471 bool "4GB"
Adrian Bunk905c3992006-03-23 02:59:55 -0800472 depends on !X86_NUMAQ
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 help
474 Select this if you have a 32-bit processor and between 1 and 4
475 gigabytes of physical RAM.
476
477config HIGHMEM64G
478 bool "64GB"
Adrian Bunk4be68a72006-02-04 23:28:05 -0800479 depends on X86_CMPXCHG64
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 help
481 Select this if you have a 32-bit processor and more than 4
482 gigabytes of physical RAM.
483
484endchoice
485
Mark Lord975b3d32006-02-01 03:06:11 -0800486choice
487 depends on EXPERIMENTAL && !X86_PAE
Andi Kleen9539d4e2006-04-27 18:39:36 -0700488 prompt "Memory split" if EMBEDDED
Mark Lord975b3d32006-02-01 03:06:11 -0800489 default VMSPLIT_3G
490 help
491 Select the desired split between kernel and user memory.
492
493 If the address range available to the kernel is less than the
494 physical memory installed, the remaining memory will be available
495 as "high memory". Accessing high memory is a little more costly
496 than low memory, as it needs to be mapped into the kernel first.
497 Note that increasing the kernel address space limits the range
498 available to user programs, making the address space there
499 tighter. Selecting anything other than the default 3G/1G split
500 will also likely make your kernel incompatible with binary-only
501 kernel modules.
502
503 If you are not absolutely sure what you are doing, leave this
504 option alone!
505
506 config VMSPLIT_3G
507 bool "3G/1G user/kernel split"
508 config VMSPLIT_3G_OPT
509 bool "3G/1G user/kernel split (for full 1G low memory)"
510 config VMSPLIT_2G
511 bool "2G/2G user/kernel split"
512 config VMSPLIT_1G
513 bool "1G/3G user/kernel split"
514endchoice
515
516config PAGE_OFFSET
517 hex
518 default 0xB0000000 if VMSPLIT_3G_OPT
519 default 0x78000000 if VMSPLIT_2G
520 default 0x40000000 if VMSPLIT_1G
521 default 0xC0000000
522
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523config HIGHMEM
524 bool
525 depends on HIGHMEM64G || HIGHMEM4G
526 default y
527
528config X86_PAE
529 bool
530 depends on HIGHMEM64G
531 default y
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700532 select RESOURCES_64BIT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533
534# Common NUMA Features
535config NUMA
536 bool "Numa Memory Allocation and Scheduler Support"
537 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
538 default n if X86_PC
539 default y if (X86_NUMAQ || X86_SUMMIT)
540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
542 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
543
Yasunori Gotoc80d79d2006-04-10 22:53:53 -0700544config NODES_SHIFT
545 int
546 default "4" if X86_NUMAQ
547 default "3"
548 depends on NEED_MULTIPLE_NODES
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550config HAVE_ARCH_BOOTMEM_NODE
551 bool
552 depends on NUMA
553 default y
554
Andy Whitcroftaf705362005-06-23 00:07:53 -0700555config ARCH_HAVE_MEMORY_PRESENT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 bool
557 depends on DISCONTIGMEM
558 default y
559
560config NEED_NODE_MEMMAP_SIZE
561 bool
Andy Whitcroft05b79bd2005-06-23 00:07:57 -0700562 depends on DISCONTIGMEM || SPARSEMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 default y
564
Dave Hansen6f167ec2005-06-23 00:07:39 -0700565config HAVE_ARCH_ALLOC_REMAP
566 bool
567 depends on NUMA
568 default y
569
Andy Whitcroft215c3402006-01-06 00:12:06 -0800570config ARCH_FLATMEM_ENABLE
571 def_bool y
572 depends on (ARCH_SELECT_MEMORY_MODEL && X86_PC)
573
Andy Whitcroft05b79bd2005-06-23 00:07:57 -0700574config ARCH_DISCONTIGMEM_ENABLE
575 def_bool y
576 depends on NUMA
577
578config ARCH_DISCONTIGMEM_DEFAULT
579 def_bool y
580 depends on NUMA
581
582config ARCH_SPARSEMEM_ENABLE
583 def_bool y
Andy Whitcroft215c3402006-01-06 00:12:06 -0800584 depends on (NUMA || (X86_PC && EXPERIMENTAL))
585 select SPARSEMEM_STATIC
Andy Whitcroft05b79bd2005-06-23 00:07:57 -0700586
587config ARCH_SELECT_MEMORY_MODEL
588 def_bool y
589 depends on ARCH_SPARSEMEM_ENABLE
590
Dave Hansen3f22ab22005-06-23 00:07:43 -0700591source "mm/Kconfig"
592
Andy Whitcroftb159d432005-06-23 00:07:52 -0700593config HAVE_ARCH_EARLY_PFN_TO_NID
594 bool
595 default y
Andy Whitcroftd41dee32005-06-23 00:07:54 -0700596 depends on NUMA
Andy Whitcroftb159d432005-06-23 00:07:52 -0700597
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598config HIGHPTE
599 bool "Allocate 3rd-level pagetables from highmem"
600 depends on HIGHMEM4G || HIGHMEM64G
601 help
602 The VM uses one page table entry for each page of physical memory.
603 For systems with a lot of RAM, this can be wasteful of precious
604 low memory. Setting this option will put user-space page table
605 entries in high memory.
606
607config MATH_EMULATION
608 bool "Math emulation"
609 ---help---
610 Linux can emulate a math coprocessor (used for floating point
611 operations) if you don't have one. 486DX and Pentium processors have
612 a math coprocessor built in, 486SX and 386 do not, unless you added
613 a 487DX or 387, respectively. (The messages during boot time can
614 give you some hints here ["man dmesg"].) Everyone needs either a
615 coprocessor or this emulation.
616
617 If you don't have a math coprocessor, you need to say Y here; if you
618 say Y here even though you have a coprocessor, the coprocessor will
619 be used nevertheless. (This behavior can be changed with the kernel
620 command line option "no387", which comes handy if your coprocessor
621 is broken. Try "man bootparam" or see the documentation of your boot
622 loader (lilo or loadlin) about how to pass options to the kernel at
623 boot time.) This means that it is a good idea to say Y here if you
624 intend to use this kernel on different machines.
625
626 More information about the internals of the Linux math coprocessor
627 emulation can be found in <file:arch/i386/math-emu/README>.
628
629 If you are not sure, say Y; apart from resulting in a 66 KB bigger
630 kernel, it won't hurt.
631
632config MTRR
633 bool "MTRR (Memory Type Range Register) support"
634 ---help---
635 On Intel P6 family processors (Pentium Pro, Pentium II and later)
636 the Memory Type Range Registers (MTRRs) may be used to control
637 processor access to memory ranges. This is most useful if you have
638 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
639 allows bus write transfers to be combined into a larger transfer
640 before bursting over the PCI/AGP bus. This can increase performance
641 of image write operations 2.5 times or more. Saying Y here creates a
642 /proc/mtrr file which may be used to manipulate your processor's
643 MTRRs. Typically the X server should use this.
644
645 This code has a reasonably generic interface so that similar
646 control registers on other processors can be easily supported
647 as well:
648
649 The Cyrix 6x86, 6x86MX and M II processors have Address Range
650 Registers (ARRs) which provide a similar functionality to MTRRs. For
651 these, the ARRs are used to emulate the MTRRs.
652 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
653 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
654 write-combining. All of these processors are supported by this code
655 and it makes sense to say Y here if you have one of them.
656
657 Saying Y here also fixes a problem with buggy SMP BIOSes which only
658 set the MTRRs for the boot CPU and not for the secondary CPUs. This
659 can lead to all sorts of problems, so it's good to say Y here.
660
661 You can safely say Y even if your machine doesn't have MTRRs, you'll
662 just add about 9 KB to your kernel.
663
664 See <file:Documentation/mtrr.txt> for more information.
665
666config EFI
667 bool "Boot from EFI support (EXPERIMENTAL)"
668 depends on ACPI
669 default n
670 ---help---
671 This enables the the kernel to boot on EFI platforms using
672 system configuration information passed to it from the firmware.
673 This also enables the kernel to use any EFI runtime services that are
674 available (such as the EFI variable services).
675
676 This option is only useful on systems that have EFI firmware
677 and will result in a kernel image that is ~8k larger. In addition,
678 you must use the latest ELILO loader available at
679 <http://elilo.sourceforge.net> in order to take advantage of
680 kernel initialization using EFI information (neither GRUB nor LILO know
681 anything about EFI). However, even with this option, the resultant
682 kernel should continue to boot on existing non-EFI platforms.
683
684config IRQBALANCE
685 bool "Enable kernel irq balancing"
686 depends on SMP && X86_IO_APIC
687 default y
688 help
689 The default yes will allow the kernel to do irq load balancing.
690 Saying no will keep the kernel from doing irq load balancing.
691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692# turning this on wastes a bunch of space.
693# Summit needs it only when NUMA is on
694config BOOT_IOREMAP
695 bool
696 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
697 default y
698
699config REGPARM
Adrian Bunk69ef4142006-03-23 02:59:28 -0800700 bool "Use register arguments"
Ingo Molnarb824eb62006-03-23 02:59:29 -0800701 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 help
Ingo Molnarb824eb62006-03-23 02:59:29 -0800703 Compile the kernel with -mregparm=3. This instructs gcc to use
704 a more efficient function call ABI which passes the first three
705 arguments of a function call via registers, which results in denser
706 and faster code.
707
708 If this option is disabled, then the default ABI of passing
709 arguments via the stack is used.
710
711 If unsure, say Y.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713config SECCOMP
714 bool "Enable seccomp to safely compute untrusted bytecode"
715 depends on PROC_FS
716 default y
717 help
718 This kernel feature is useful for number crunching applications
719 that may need to compute untrusted bytecode during their
720 execution. By using pipes or other transports made available to
721 the process as file descriptors supporting the read/write
722 syscalls, it's possible to isolate those applications in
723 their own address space using seccomp. Once seccomp is
724 enabled via /proc/<pid>/seccomp, it cannot be disabled
725 and the task is only allowed to execute a few safe syscalls
726 defined by each seccomp mode.
727
728 If unsure, say Y. Only embedded should say N here.
729
Christoph Lameter59121002005-06-23 00:08:25 -0700730source kernel/Kconfig.hz
731
Eric W. Biederman5033cba2005-06-25 14:57:56 -0700732config KEXEC
733 bool "kexec system call (EXPERIMENTAL)"
734 depends on EXPERIMENTAL
735 help
736 kexec is a system call that implements the ability to shutdown your
737 current kernel, and to start another kernel. It is like a reboot
Egry Gabor48a12042006-06-26 18:47:15 +0200738 but it is independent of the system firmware. And like a reboot
Eric W. Biederman5033cba2005-06-25 14:57:56 -0700739 you can start any kernel with it, not just Linux.
740
741 The name comes from the similiarity to the exec system call.
742
743 It is an ongoing process to be certain the hardware in a machine
744 is properly shutdown, so do not be surprised if this code does not
745 initially work for you. It may help to enable device hotplugging
746 support. As of this writing the exact hardware interface is
747 strongly in flux, so no good recommendation can be made.
748
Vivek Goyal5f016452005-06-25 14:58:19 -0700749config CRASH_DUMP
750 bool "kernel crash dumps (EXPERIMENTAL)"
Vivek Goyal5f016452005-06-25 14:58:19 -0700751 depends on EXPERIMENTAL
752 depends on HIGHMEM
753 help
754 Generate crash dump after being started by kexec.
Maneesh Soni05970d42006-01-09 20:51:52 -0800755
756config PHYSICAL_START
757 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
758
759 default "0x1000000" if CRASH_DUMP
760 default "0x100000"
761 help
762 This gives the physical address where the kernel is loaded. Normally
763 for regular kernels this value is 0x100000 (1MB). But in the case
764 of kexec on panic the fail safe kernel needs to run at a different
765 address than the panic-ed kernel. This option is used to set the load
766 address for kernels used to capture crash dump on being kexec'ed
767 after panic. The default value for crash dump kernels is
768 0x1000000 (16MB). This can also be set based on the "X" value as
769 specified in the "crashkernel=YM@XM" command line boot parameter
770 passed to the panic-ed kernel. Typically this parameter is set as
771 crashkernel=64M@16M. Please take a look at
772 Documentation/kdump/kdump.txt for more details about crash dumps.
773
774 Don't change this unless you know what you are doing.
775
Randy Dunlapce63ad72006-01-14 13:20:51 -0800776config HOTPLUG_CPU
777 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
Ashok Raj35076bd2006-04-27 18:39:30 -0700778 depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
Randy Dunlapce63ad72006-01-14 13:20:51 -0800779 ---help---
Pavel Machekb2d596d2006-05-15 09:44:34 -0700780 Say Y here to experiment with turning CPUs off and on, and to
781 enable suspend on SMP systems. CPUs can be controlled through
782 /sys/devices/system/cpu.
Randy Dunlapce63ad72006-01-14 13:20:51 -0800783
Randy Dunlapce63ad72006-01-14 13:20:51 -0800784
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785endmenu
786
787
788menu "Power management options (ACPI, APM)"
789 depends on !X86_VOYAGER
790
791source kernel/power/Kconfig
792
793source "drivers/acpi/Kconfig"
794
795menu "APM (Advanced Power Management) BIOS Support"
796depends on PM && !X86_VISWS
797
798config APM
799 tristate "APM (Advanced Power Management) BIOS support"
Dave Jones987d46132006-01-08 01:05:09 -0800800 depends on PM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 ---help---
802 APM is a BIOS specification for saving power using several different
803 techniques. This is mostly useful for battery powered laptops with
804 APM compliant BIOSes. If you say Y here, the system time will be
805 reset after a RESUME operation, the /proc/apm device will provide
806 battery status information, and user-space programs will receive
807 notification of APM "events" (e.g. battery status change).
808
809 If you select "Y" here, you can disable actual use of the APM
810 BIOS by passing the "apm=off" option to the kernel at boot time.
811
812 Note that the APM support is almost completely disabled for
813 machines with more than one CPU.
814
815 In order to use APM, you will need supporting software. For location
816 and more information, read <file:Documentation/pm.txt> and the
817 Battery Powered Linux mini-HOWTO, available from
818 <http://www.tldp.org/docs.html#howto>.
819
820 This driver does not spin down disk drives (see the hdparm(8)
821 manpage ("man 8 hdparm") for that), and it doesn't turn off
822 VESA-compliant "green" monitors.
823
824 This driver does not support the TI 4000M TravelMate and the ACER
825 486/DX4/75 because they don't have compliant BIOSes. Many "green"
826 desktop machines also don't have compliant BIOSes, and this driver
827 may cause those machines to panic during the boot phase.
828
829 Generally, if you don't have a battery in your machine, there isn't
830 much point in using this driver and you should say N. If you get
831 random kernel OOPSes or reboots that don't seem to be related to
832 anything, try disabling/enabling this option (or disabling/enabling
833 APM in your BIOS).
834
835 Some other things you should try when experiencing seemingly random,
836 "weird" problems:
837
838 1) make sure that you have enough swap space and that it is
839 enabled.
840 2) pass the "no-hlt" option to the kernel
841 3) switch on floating point emulation in the kernel and pass
842 the "no387" option to the kernel
843 4) pass the "floppy=nodma" option to the kernel
844 5) pass the "mem=4M" option to the kernel (thereby disabling
845 all but the first 4 MB of RAM)
846 6) make sure that the CPU is not over clocked.
847 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
848 8) disable the cache from your BIOS settings
849 9) install a fan for the video card or exchange video RAM
850 10) install a better fan for the CPU
851 11) exchange RAM chips
852 12) exchange the motherboard.
853
854 To compile this driver as a module, choose M here: the
855 module will be called apm.
856
857config APM_IGNORE_USER_SUSPEND
858 bool "Ignore USER SUSPEND"
859 depends on APM
860 help
861 This option will ignore USER SUSPEND requests. On machines with a
862 compliant APM BIOS, you want to say N. However, on the NEC Versa M
863 series notebooks, it is necessary to say Y because of a BIOS bug.
864
865config APM_DO_ENABLE
866 bool "Enable PM at boot time"
867 depends on APM
868 ---help---
869 Enable APM features at boot time. From page 36 of the APM BIOS
870 specification: "When disabled, the APM BIOS does not automatically
871 power manage devices, enter the Standby State, enter the Suspend
872 State, or take power saving steps in response to CPU Idle calls."
873 This driver will make CPU Idle calls when Linux is idle (unless this
874 feature is turned off -- see "Do CPU IDLE calls", below). This
875 should always save battery power, but more complicated APM features
876 will be dependent on your BIOS implementation. You may need to turn
877 this option off if your computer hangs at boot time when using APM
878 support, or if it beeps continuously instead of suspending. Turn
879 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
880 T400CDT. This is off by default since most machines do fine without
881 this feature.
882
883config APM_CPU_IDLE
884 bool "Make CPU Idle calls when idle"
885 depends on APM
886 help
887 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
888 On some machines, this can activate improved power savings, such as
889 a slowed CPU clock rate, when the machine is idle. These idle calls
890 are made after the idle loop has run for some length of time (e.g.,
891 333 mS). On some machines, this will cause a hang at boot time or
892 whenever the CPU becomes idle. (On machines with more than one CPU,
893 this option does nothing.)
894
895config APM_DISPLAY_BLANK
896 bool "Enable console blanking using APM"
897 depends on APM
898 help
899 Enable console blanking using the APM. Some laptops can use this to
900 turn off the LCD backlight when the screen blanker of the Linux
901 virtual console blanks the screen. Note that this is only used by
902 the virtual console screen blanker, and won't turn off the backlight
903 when using the X Window system. This also doesn't have anything to
904 do with your VESA-compliant power-saving monitor. Further, this
905 option doesn't work for all laptops -- it might not turn off your
906 backlight at all, or it might print a lot of errors to the console,
907 especially if you are using gpm.
908
909config APM_RTC_IS_GMT
910 bool "RTC stores time in GMT"
911 depends on APM
912 help
913 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
914 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
915 stores localtime.
916
917 It is in fact recommended to store GMT in your RTC, because then you
918 don't have to worry about daylight savings time changes. The only
919 reason not to use GMT in your RTC is if you also run a broken OS
920 that doesn't understand GMT.
921
922config APM_ALLOW_INTS
923 bool "Allow interrupts during APM BIOS calls"
924 depends on APM
925 help
926 Normally we disable external interrupts while we are making calls to
927 the APM BIOS as a measure to lessen the effects of a badly behaving
928 BIOS implementation. The BIOS should reenable interrupts if it
929 needs to. Unfortunately, some BIOSes do not -- especially those in
930 many of the newer IBM Thinkpads. If you experience hangs when you
931 suspend, try setting this to Y. Otherwise, say N.
932
933config APM_REAL_MODE_POWER_OFF
934 bool "Use real mode APM BIOS call to power off"
935 depends on APM
936 help
937 Use real mode APM BIOS calls to switch off the computer. This is
938 a work-around for a number of buggy BIOSes. Switch this option on if
939 your computer crashes instead of powering off properly.
940
941endmenu
942
943source "arch/i386/kernel/cpu/cpufreq/Kconfig"
944
945endmenu
946
947menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
948
949config PCI
950 bool "PCI support" if !X86_VISWS
951 depends on !X86_VOYAGER
952 default y if X86_VISWS
953 help
954 Find out whether you have a PCI motherboard. PCI is the name of a
955 bus system, i.e. the way the CPU talks to the other stuff inside
956 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
957 VESA. If you have PCI, say Y, otherwise N.
958
959 The PCI-HOWTO, available from
960 <http://www.tldp.org/docs.html#howto>, contains valuable
961 information about which PCI hardware does work under Linux and which
962 doesn't.
963
964choice
965 prompt "PCI access mode"
966 depends on PCI && !X86_VISWS
967 default PCI_GOANY
968 ---help---
969 On PCI systems, the BIOS can be used to detect the PCI devices and
970 determine their configuration. However, some old PCI motherboards
971 have BIOS bugs and may crash if this is done. Also, some embedded
972 PCI-based systems don't have any BIOS at all. Linux can also try to
973 detect the PCI hardware directly without using the BIOS.
974
975 With this option, you can specify how Linux should detect the
976 PCI devices. If you choose "BIOS", the BIOS will be used,
977 if you choose "Direct", the BIOS won't be used, and if you
978 choose "MMConfig", then PCI Express MMCONFIG will be used.
979 If you choose "Any", the kernel will try MMCONFIG, then the
980 direct access method and falls back to the BIOS if that doesn't
981 work. If unsure, go with the default, which is "Any".
982
983config PCI_GOBIOS
984 bool "BIOS"
985
986config PCI_GOMMCONFIG
987 bool "MMConfig"
988
989config PCI_GODIRECT
990 bool "Direct"
991
992config PCI_GOANY
993 bool "Any"
994
995endchoice
996
997config PCI_BIOS
998 bool
999 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1000 default y
1001
1002config PCI_DIRECT
1003 bool
1004 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1005 default y
1006
1007config PCI_MMCONFIG
1008 bool
Alexander Nyberg8aadff72005-05-27 12:48:50 +02001009 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 default y
1011
1012source "drivers/pci/pcie/Kconfig"
1013
1014source "drivers/pci/Kconfig"
1015
Al Viro5cae8412005-05-04 05:39:22 +01001016config ISA_DMA_API
1017 bool
1018 default y
1019
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020config ISA
1021 bool "ISA support"
1022 depends on !(X86_VOYAGER || X86_VISWS)
1023 help
1024 Find out whether you have ISA slots on your motherboard. ISA is the
1025 name of a bus system, i.e. the way the CPU talks to the other stuff
1026 inside your box. Other bus systems are PCI, EISA, MicroChannel
1027 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1028 newer boards don't support it. If you have ISA, say Y, otherwise N.
1029
1030config EISA
1031 bool "EISA support"
1032 depends on ISA
1033 ---help---
1034 The Extended Industry Standard Architecture (EISA) bus was
1035 developed as an open alternative to the IBM MicroChannel bus.
1036
1037 The EISA bus provided some of the features of the IBM MicroChannel
1038 bus while maintaining backward compatibility with cards made for
1039 the older ISA bus. The EISA bus saw limited use between 1988 and
1040 1995 when it was made obsolete by the PCI bus.
1041
1042 Say Y here if you are building a kernel for an EISA-based machine.
1043
1044 Otherwise, say N.
1045
1046source "drivers/eisa/Kconfig"
1047
1048config MCA
1049 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1050 default y if X86_VOYAGER
1051 help
1052 MicroChannel Architecture is found in some IBM PS/2 machines and
1053 laptops. It is a bus system similar to PCI or ISA. See
1054 <file:Documentation/mca.txt> (and especially the web page given
1055 there) before attempting to build an MCA bus kernel.
1056
1057source "drivers/mca/Kconfig"
1058
1059config SCx200
1060 tristate "NatSemi SCx200 support"
1061 depends on !X86_VOYAGER
1062 help
Jim Cromie6ae74402006-06-26 00:25:19 -07001063 This provides basic support for National Semiconductor's
1064 (now AMD's) Geode processors. The driver probes for the
1065 PCI-IDs of several on-chip devices, so its a good dependency
1066 for other scx200_* drivers.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067
Jim Cromie6ae74402006-06-26 00:25:19 -07001068 If compiled as a module, the driver is named scx200.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069
Jim Cromie6ae74402006-06-26 00:25:19 -07001070config SCx200HR_TIMER
1071 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1072 depends on SCx200 && GENERIC_TIME
1073 default y
1074 help
1075 This driver provides a clocksource built upon the on-chip
1076 27MHz high-resolution timer. Its also a workaround for
1077 NSC Geode SC-1100's buggy TSC, which loses time when the
1078 processor goes idle (as is done by the scheduler). The
1079 other workaround is idle=poll boot option.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
Andi Kleena32073b2006-06-26 13:56:40 +02001081config K8_NB
1082 def_bool y
1083 depends on AGP_AMD64
1084
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085source "drivers/pcmcia/Kconfig"
1086
1087source "drivers/pci/hotplug/Kconfig"
1088
1089endmenu
1090
1091menu "Executable file formats"
1092
1093source "fs/Kconfig.binfmt"
1094
1095endmenu
1096
Sam Ravnborgd5950b42005-07-11 21:03:49 -07001097source "net/Kconfig"
1098
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099source "drivers/Kconfig"
1100
1101source "fs/Kconfig"
1102
Prasanna S Panchamukhicd6b0762005-11-07 00:59:14 -08001103menu "Instrumentation Support"
1104 depends on EXPERIMENTAL
1105
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106source "arch/i386/oprofile/Kconfig"
1107
Prasanna S Panchamukhicd6b0762005-11-07 00:59:14 -08001108config KPROBES
1109 bool "Kprobes (EXPERIMENTAL)"
Linus Torvaldsadd2b6f2006-02-26 20:24:40 -08001110 depends on EXPERIMENTAL && MODULES
Prasanna S Panchamukhicd6b0762005-11-07 00:59:14 -08001111 help
1112 Kprobes allows you to trap at almost any kernel address and
1113 execute a callback function. register_kprobe() establishes
1114 a probepoint and specifies the callback. Kprobes is useful
1115 for kernel debugging, non-intrusive instrumentation and testing.
1116 If in doubt, say "N".
1117endmenu
1118
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119source "arch/i386/Kconfig.debug"
1120
1121source "security/Kconfig"
1122
1123source "crypto/Kconfig"
1124
1125source "lib/Kconfig"
1126
1127#
1128# Use the generic interrupt handling code in kernel/irq/:
1129#
1130config GENERIC_HARDIRQS
1131 bool
1132 default y
1133
1134config GENERIC_IRQ_PROBE
1135 bool
1136 default y
1137
Ashok Raj54d5d422005-09-06 15:16:15 -07001138config GENERIC_PENDING_IRQ
1139 bool
1140 depends on GENERIC_HARDIRQS && SMP
1141 default y
1142
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143config X86_SMP
1144 bool
1145 depends on SMP && !X86_VOYAGER
1146 default y
1147
1148config X86_HT
1149 bool
1150 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1151 default y
1152
1153config X86_BIOS_REBOOT
1154 bool
1155 depends on !(X86_VISWS || X86_VOYAGER)
1156 default y
1157
1158config X86_TRAMPOLINE
1159 bool
1160 depends on X86_SMP || (X86_VOYAGER && SMP)
1161 default y
Thomas Gleixner97fc79f2006-01-09 20:52:31 -08001162
1163config KTIME_SCALAR
1164 bool
1165 default y