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1 #
2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
4 #
6 mainmenu "Linux Kernel Configuration"
8 config X86
9 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.
17 config MMU
18 bool
19 default y
21 config SBUS
22 bool
24 config UID16
25 bool
26 default y
28 config GENERIC_ISA_DMA
29 bool
30 default y
32 config GENERIC_IOMAP
33 bool
34 default y
36 source "init/Kconfig"
38 menu "Processor type and features"
40 choice
41 prompt "Subarchitecture Type"
42 default X86_PC
44 config X86_PC
45 bool "PC-compatible"
46 help
47 Choose this option if your computer is a standard PC or compatible.
49 config X86_ELAN
50 bool "AMD Elan"
51 help
52 Select this for an AMD Elan processor.
54 Do not use this option for K6/Athlon/Opteron processors!
56 If unsure, choose "PC-compatible" instead.
58 config X86_VOYAGER
59 bool "Voyager (NCR)"
60 help
61 Voyager is an MCA-based 32-way capable SMP architecture proprietary
62 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
64 *** 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.
69 config X86_NUMAQ
70 bool "NUMAQ (IBM/Sequent)"
71 select NUMA
72 help
73 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
74 multiquad box. This changes the way that processors are bootstrapped,
75 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
76 You will need a new lynxer.elf file to flash your firmware with - send
77 email to <Martin.Bligh@us.ibm.com>.
79 config X86_SUMMIT
80 bool "Summit/EXA (IBM x440)"
81 depends on SMP
82 help
83 This option is needed for IBM systems that use the Summit/EXA chipset.
84 In particular, it is needed for the x440.
86 If you don't have one of these computers, you should say N here.
88 config X86_BIGSMP
89 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
90 depends on SMP
91 help
92 This option is needed for the systems that have more than 8 CPUs
93 and if the system is not of any sub-arch type above.
95 If you don't have such a system, you should say N here.
97 config X86_VISWS
98 bool "SGI 320/540 (Visual Workstation)"
99 help
100 The SGI Visual Workstation series is an IA32-based workstation
101 based on SGI systems chips with some legacy PC hardware attached.
103 Say Y here to create a kernel to run on the SGI 320 or 540.
105 A kernel compiled for the Visual Workstation will not run on PCs
106 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
108 config X86_GENERICARCH
109 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
110 depends on SMP
111 help
112 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
113 It is intended for a generic binary kernel.
115 config X86_ES7000
116 bool "Support for Unisys ES7000 IA32 series"
117 depends on SMP
118 help
119 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
120 supposed to run on an IA32-based Unisys ES7000 system.
121 Only choose this option if you have such a system, otherwise you
122 should say N here.
124 endchoice
126 config ACPI_SRAT
127 bool
128 default y
129 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
131 config X86_SUMMIT_NUMA
132 bool
133 default y
134 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
136 config X86_CYCLONE_TIMER
137 bool
138 default y
139 depends on X86_SUMMIT || X86_GENERICARCH
141 config ES7000_CLUSTERED_APIC
142 bool
143 default y
144 depends on SMP && X86_ES7000 && MPENTIUMIII
146 if !X86_ELAN
148 choice
149 prompt "Processor family"
150 default M686
152 config M386
153 bool "386"
154 ---help---
155 This is the processor type of your CPU. This information is used for
156 optimizing purposes. In order to compile a kernel that can run on
157 all x86 CPU types (albeit not optimally fast), you can specify
158 "386" here.
160 The kernel will not necessarily run on earlier architectures than
161 the one you have chosen, e.g. a Pentium optimized kernel will run on
162 a PPro, but not necessarily on a i486.
164 Here are the settings recommended for greatest speed:
165 - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
166 486DLC/DLC2, UMC 486SX-S and NexGen Nx586. Only "386" kernels
167 will run on a 386 class machine.
168 - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
169 SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
170 - "586" for generic Pentium CPUs lacking the TSC
171 (time stamp counter) register.
172 - "Pentium-Classic" for the Intel Pentium.
173 - "Pentium-MMX" for the Intel Pentium MMX.
174 - "Pentium-Pro" for the Intel Pentium Pro.
175 - "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
176 - "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
177 - "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
178 - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
179 - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
180 - "Crusoe" for the Transmeta Crusoe series.
181 - "Efficeon" for the Transmeta Efficeon series.
182 - "Winchip-C6" for original IDT Winchip.
183 - "Winchip-2" for IDT Winchip 2.
184 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
185 - "GeodeGX1" for Geode GX1 (Cyrix MediaGX).
186 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
187 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
189 If you don't know what to do, choose "386".
191 config M486
192 bool "486"
193 help
194 Select this for a 486 series processor, either Intel or one of the
195 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
196 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
197 U5S.
199 config M586
200 bool "586/K5/5x86/6x86/6x86MX"
201 help
202 Select this for an 586 or 686 series processor such as the AMD K5,
203 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
204 assume the RDTSC (Read Time Stamp Counter) instruction.
206 config M586TSC
207 bool "Pentium-Classic"
208 help
209 Select this for a Pentium Classic processor with the RDTSC (Read
210 Time Stamp Counter) instruction for benchmarking.
212 config M586MMX
213 bool "Pentium-MMX"
214 help
215 Select this for a Pentium with the MMX graphics/multimedia
216 extended instructions.
218 config M686
219 bool "Pentium-Pro"
220 help
221 Select this for Intel Pentium Pro chips. This enables the use of
222 Pentium Pro extended instructions, and disables the init-time guard
223 against the f00f bug found in earlier Pentiums.
225 config MPENTIUMII
226 bool "Pentium-II/Celeron(pre-Coppermine)"
227 help
228 Select this for Intel chips based on the Pentium-II and
229 pre-Coppermine Celeron core. This option enables an unaligned
230 copy optimization, compiles the kernel with optimization flags
231 tailored for the chip, and applies any applicable Pentium Pro
232 optimizations.
234 config MPENTIUMIII
235 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
236 help
237 Select this for Intel chips based on the Pentium-III and
238 Celeron-Coppermine core. This option enables use of some
239 extended prefetch instructions in addition to the Pentium II
240 extensions.
242 config MPENTIUMM
243 bool "Pentium M"
244 help
245 Select this for Intel Pentium M (not Pentium-4 M)
246 notebook chips.
248 config MPENTIUM4
249 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
250 help
251 Select this for Intel Pentium 4 chips. This includes the
252 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
253 (not Pentium M) chips. This option enables compile flags
254 optimized for the chip, uses the correct cache shift, and
255 applies any applicable Pentium III optimizations.
257 config MK6
258 bool "K6/K6-II/K6-III"
259 help
260 Select this for an AMD K6-family processor. Enables use of
261 some extended instructions, and passes appropriate optimization
262 flags to GCC.
264 config MK7
265 bool "Athlon/Duron/K7"
266 help
267 Select this for an AMD Athlon K7-family processor. Enables use of
268 some extended instructions, and passes appropriate optimization
269 flags to GCC.
271 config MK8
272 bool "Opteron/Athlon64/Hammer/K8"
273 help
274 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
275 use of some extended instructions, and passes appropriate optimization
276 flags to GCC.
278 config MCRUSOE
279 bool "Crusoe"
280 help
281 Select this for a Transmeta Crusoe processor. Treats the processor
282 like a 586 with TSC, and sets some GCC optimization flags (like a
283 Pentium Pro with no alignment requirements).
285 config MEFFICEON
286 bool "Efficeon"
287 help
288 Select this for a Transmeta Efficeon processor.
290 config MWINCHIPC6
291 bool "Winchip-C6"
292 help
293 Select this for an IDT Winchip C6 chip. Linux and GCC
294 treat this chip as a 586TSC with some extended instructions
295 and alignment requirements.
297 config MWINCHIP2
298 bool "Winchip-2"
299 help
300 Select this for an IDT Winchip-2. Linux and GCC
301 treat this chip as a 586TSC with some extended instructions
302 and alignment requirements.
304 config MWINCHIP3D
305 bool "Winchip-2A/Winchip-3"
306 help
307 Select this for an IDT Winchip-2A or 3. Linux and GCC
308 treat this chip as a 586TSC with some extended instructions
309 and alignment reqirements. Also enable out of order memory
310 stores for this CPU, which can increase performance of some
311 operations.
313 config MGEODEGX1
314 bool "GeodeGX1"
315 help
316 Select this for a Geode GX1 (Cyrix MediaGX) chip.
318 config MCYRIXIII
319 bool "CyrixIII/VIA-C3"
320 help
321 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
322 treat this chip as a generic 586. Whilst the CPU is 686 class,
323 it lacks the cmov extension which gcc assumes is present when
324 generating 686 code.
325 Note that Nehemiah (Model 9) and above will not boot with this
326 kernel due to them lacking the 3DNow! instructions used in earlier
327 incarnations of the CPU.
329 config MVIAC3_2
330 bool "VIA C3-2 (Nehemiah)"
331 help
332 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
333 of SSE and tells gcc to treat the CPU as a 686.
334 Note, this kernel will not boot on older (pre model 9) C3s.
336 endchoice
338 config X86_GENERIC
339 bool "Generic x86 support"
340 help
341 Instead of just including optimizations for the selected
342 x86 variant (e.g. PII, Crusoe or Athlon), include some more
343 generic optimizations as well. This will make the kernel
344 perform better on x86 CPUs other than that selected.
346 This is really intended for distributors who need more
347 generic optimizations.
349 endif
351 #
352 # Define implied options from the CPU selection here
353 #
354 config X86_CMPXCHG
355 bool
356 depends on !M386
357 default y
359 config X86_XADD
360 bool
361 depends on !M386
362 default y
364 config X86_L1_CACHE_SHIFT
365 int
366 default "7" if MPENTIUM4 || X86_GENERIC
367 default "4" if X86_ELAN || M486 || M386
368 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODEGX1
369 default "6" if MK7 || MK8 || MPENTIUMM
371 config RWSEM_GENERIC_SPINLOCK
372 bool
373 depends on M386
374 default y
376 config RWSEM_XCHGADD_ALGORITHM
377 bool
378 depends on !M386
379 default y
381 config GENERIC_CALIBRATE_DELAY
382 bool
383 default y
385 config X86_PPRO_FENCE
386 bool
387 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1
388 default y
390 config X86_F00F_BUG
391 bool
392 depends on M586MMX || M586TSC || M586 || M486 || M386
393 default y
395 config X86_WP_WORKS_OK
396 bool
397 depends on !M386
398 default y
400 config X86_INVLPG
401 bool
402 depends on !M386
403 default y
405 config X86_BSWAP
406 bool
407 depends on !M386
408 default y
410 config X86_POPAD_OK
411 bool
412 depends on !M386
413 default y
415 config X86_ALIGNMENT_16
416 bool
417 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
418 default y
420 config X86_GOOD_APIC
421 bool
422 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
423 default y
425 config X86_INTEL_USERCOPY
426 bool
427 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
428 default y
430 config X86_USE_PPRO_CHECKSUM
431 bool
432 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
433 default y
435 config X86_USE_3DNOW
436 bool
437 depends on MCYRIXIII || MK7
438 default y
440 config X86_OOSTORE
441 bool
442 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
443 default y
445 config HPET_TIMER
446 bool "HPET Timer Support"
447 help
448 This enables the use of the HPET for the kernel's internal timer.
449 HPET is the next generation timer replacing legacy 8254s.
450 You can safely choose Y here. However, HPET will only be
451 activated if the platform and the BIOS support this feature.
452 Otherwise the 8254 will be used for timing services.
454 Choose N to continue using the legacy 8254 timer.
456 config HPET_EMULATE_RTC
457 bool "Provide RTC interrupt"
458 depends on HPET_TIMER && RTC=y
460 config SMP
461 bool "Symmetric multi-processing support"
462 ---help---
463 This enables support for systems with more than one CPU. If you have
464 a system with only one CPU, like most personal computers, say N. If
465 you have a system with more than one CPU, say Y.
467 If you say N here, the kernel will run on single and multiprocessor
468 machines, but will use only one CPU of a multiprocessor machine. If
469 you say Y here, the kernel will run on many, but not all,
470 singleprocessor machines. On a singleprocessor machine, the kernel
471 will run faster if you say N here.
473 Note that if you say Y here and choose architecture "586" or
474 "Pentium" under "Processor family", the kernel will not work on 486
475 architectures. Similarly, multiprocessor kernels for the "PPro"
476 architecture may not work on all Pentium based boards.
478 People using multiprocessor machines who say Y here should also say
479 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
480 Management" code will be disabled if you say Y here.
482 See also the <file:Documentation/smp.txt>,
483 <file:Documentation/i386/IO-APIC.txt>,
484 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
485 <http://www.tldp.org/docs.html#howto>.
487 If you don't know what to do here, say N.
489 config NR_CPUS
490 int "Maximum number of CPUs (2-255)"
491 range 2 255
492 depends on SMP
493 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
494 default "8"
495 help
496 This allows you to specify the maximum number of CPUs which this
497 kernel will support. The maximum supported value is 255 and the
498 minimum value which makes sense is 2.
500 This is purely to save memory - each supported CPU adds
501 approximately eight kilobytes to the kernel image.
503 config SCHED_SMT
504 bool "SMT (Hyperthreading) scheduler support"
505 depends on SMP
506 default off
507 help
508 SMT scheduler support improves the CPU scheduler's decision making
509 when dealing with Intel Pentium 4 chips with HyperThreading at a
510 cost of slightly increased overhead in some places. If unsure say
511 N here.
513 source "kernel/Kconfig.preempt"
515 config X86_UP_APIC
516 bool "Local APIC support on uniprocessors"
517 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
518 help
519 A local APIC (Advanced Programmable Interrupt Controller) is an
520 integrated interrupt controller in the CPU. If you have a single-CPU
521 system which has a processor with a local APIC, you can say Y here to
522 enable and use it. If you say Y here even though your machine doesn't
523 have a local APIC, then the kernel will still run with no slowdown at
524 all. The local APIC supports CPU-generated self-interrupts (timer,
525 performance counters), and the NMI watchdog which detects hard
526 lockups.
528 config X86_UP_IOAPIC
529 bool "IO-APIC support on uniprocessors"
530 depends on X86_UP_APIC
531 help
532 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
533 SMP-capable replacement for PC-style interrupt controllers. Most
534 SMP systems and many recent uniprocessor systems have one.
536 If you have a single-CPU system with an IO-APIC, you can say Y here
537 to use it. If you say Y here even though your machine doesn't have
538 an IO-APIC, then the kernel will still run with no slowdown at all.
540 config X86_LOCAL_APIC
541 bool
542 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
543 default y
545 config X86_IO_APIC
546 bool
547 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
548 default y
550 config X86_VISWS_APIC
551 bool
552 depends on X86_VISWS
553 default y
555 config X86_TSC
556 bool
557 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
558 default y
560 config X86_MCE
561 bool "Machine Check Exception"
562 depends on !X86_VOYAGER
563 ---help---
564 Machine Check Exception support allows the processor to notify the
565 kernel if it detects a problem (e.g. overheating, component failure).
566 The action the kernel takes depends on the severity of the problem,
567 ranging from a warning message on the console, to halting the machine.
568 Your processor must be a Pentium or newer to support this - check the
569 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
570 have a design flaw which leads to false MCE events - hence MCE is
571 disabled on all P5 processors, unless explicitly enabled with "mce"
572 as a boot argument. Similarly, if MCE is built in and creates a
573 problem on some new non-standard machine, you can boot with "nomce"
574 to disable it. MCE support simply ignores non-MCE processors like
575 the 386 and 486, so nearly everyone can say Y here.
577 config X86_MCE_NONFATAL
578 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
579 depends on X86_MCE
580 help
581 Enabling this feature starts a timer that triggers every 5 seconds which
582 will look at the machine check registers to see if anything happened.
583 Non-fatal problems automatically get corrected (but still logged).
584 Disable this if you don't want to see these messages.
585 Seeing the messages this option prints out may be indicative of dying hardware,
586 or out-of-spec (ie, overclocked) hardware.
587 This option only does something on certain CPUs.
588 (AMD Athlon/Duron and Intel Pentium 4)
590 config X86_MCE_P4THERMAL
591 bool "check for P4 thermal throttling interrupt."
592 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
593 help
594 Enabling this feature will cause a message to be printed when the P4
595 enters thermal throttling.
597 config TOSHIBA
598 tristate "Toshiba Laptop support"
599 ---help---
600 This adds a driver to safely access the System Management Mode of
601 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
602 not work on models with a Phoenix BIOS. The System Management Mode
603 is used to set the BIOS and power saving options on Toshiba portables.
605 For information on utilities to make use of this driver see the
606 Toshiba Linux utilities web site at:
607 <http://www.buzzard.org.uk/toshiba/>.
609 Say Y if you intend to run this kernel on a Toshiba portable.
610 Say N otherwise.
612 config I8K
613 tristate "Dell laptop support"
614 ---help---
615 This adds a driver to safely access the System Management Mode
616 of the CPU on the Dell Inspiron 8000. The System Management Mode
617 is used to read cpu temperature and cooling fan status and to
618 control the fans on the I8K portables.
620 This driver has been tested only on the Inspiron 8000 but it may
621 also work with other Dell laptops. You can force loading on other
622 models by passing the parameter `force=1' to the module. Use at
623 your own risk.
625 For information on utilities to make use of this driver see the
626 I8K Linux utilities web site at:
627 <http://people.debian.org/~dz/i8k/>
629 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
630 Say N otherwise.
632 config X86_REBOOTFIXUPS
633 bool "Enable X86 board specific fixups for reboot"
634 depends on X86
635 default n
636 ---help---
637 This enables chipset and/or board specific fixups to be done
638 in order to get reboot to work correctly. This is only needed on
639 some combinations of hardware and BIOS. The symptom, for which
640 this config is intended, is when reboot ends with a stalled/hung
641 system.
643 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
644 combination.
646 Say Y if you want to enable the fixup. Currently, it's safe to
647 enable this option even if you don't need it.
648 Say N otherwise.
650 config MICROCODE
651 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
652 ---help---
653 If you say Y here and also to "/dev file system support" in the
654 'File systems' section, you will be able to update the microcode on
655 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
656 Pentium III, Pentium 4, Xeon etc. You will obviously need the
657 actual microcode binary data itself which is not shipped with the
658 Linux kernel.
660 For latest news and information on obtaining all the required
661 ingredients for this driver, check:
662 <http://www.urbanmyth.org/microcode/>.
664 To compile this driver as a module, choose M here: the
665 module will be called microcode.
667 config X86_MSR
668 tristate "/dev/cpu/*/msr - Model-specific register support"
669 help
670 This device gives privileged processes access to the x86
671 Model-Specific Registers (MSRs). It is a character device with
672 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
673 MSR accesses are directed to a specific CPU on multi-processor
674 systems.
676 config X86_CPUID
677 tristate "/dev/cpu/*/cpuid - CPU information support"
678 help
679 This device gives processes access to the x86 CPUID instruction to
680 be executed on a specific processor. It is a character device
681 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
682 /dev/cpu/31/cpuid.
684 source "drivers/firmware/Kconfig"
686 choice
687 prompt "High Memory Support"
688 default NOHIGHMEM
690 config NOHIGHMEM
691 bool "off"
692 ---help---
693 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
694 However, the address space of 32-bit x86 processors is only 4
695 Gigabytes large. That means that, if you have a large amount of
696 physical memory, not all of it can be "permanently mapped" by the
697 kernel. The physical memory that's not permanently mapped is called
698 "high memory".
700 If you are compiling a kernel which will never run on a machine with
701 more than 1 Gigabyte total physical RAM, answer "off" here (default
702 choice and suitable for most users). This will result in a "3GB/1GB"
703 split: 3GB are mapped so that each process sees a 3GB virtual memory
704 space and the remaining part of the 4GB virtual memory space is used
705 by the kernel to permanently map as much physical memory as
706 possible.
708 If the machine has between 1 and 4 Gigabytes physical RAM, then
709 answer "4GB" here.
711 If more than 4 Gigabytes is used then answer "64GB" here. This
712 selection turns Intel PAE (Physical Address Extension) mode on.
713 PAE implements 3-level paging on IA32 processors. PAE is fully
714 supported by Linux, PAE mode is implemented on all recent Intel
715 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
716 then the kernel will not boot on CPUs that don't support PAE!
718 The actual amount of total physical memory will either be
719 auto detected or can be forced by using a kernel command line option
720 such as "mem=256M". (Try "man bootparam" or see the documentation of
721 your boot loader (lilo or loadlin) about how to pass options to the
722 kernel at boot time.)
724 If unsure, say "off".
726 config HIGHMEM4G
727 bool "4GB"
728 help
729 Select this if you have a 32-bit processor and between 1 and 4
730 gigabytes of physical RAM.
732 config HIGHMEM64G
733 bool "64GB"
734 help
735 Select this if you have a 32-bit processor and more than 4
736 gigabytes of physical RAM.
738 endchoice
740 config HIGHMEM
741 bool
742 depends on HIGHMEM64G || HIGHMEM4G
743 default y
745 config X86_PAE
746 bool
747 depends on HIGHMEM64G
748 default y
750 # Common NUMA Features
751 config NUMA
752 bool "Numa Memory Allocation and Scheduler Support"
753 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
754 default n if X86_PC
755 default y if (X86_NUMAQ || X86_SUMMIT)
757 # Need comments to help the hapless user trying to turn on NUMA support
758 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
759 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
761 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
762 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
764 config HAVE_ARCH_BOOTMEM_NODE
765 bool
766 depends on NUMA
767 default y
769 config ARCH_HAVE_MEMORY_PRESENT
770 bool
771 depends on DISCONTIGMEM
772 default y
774 config NEED_NODE_MEMMAP_SIZE
775 bool
776 depends on DISCONTIGMEM || SPARSEMEM
777 default y
779 config HAVE_ARCH_ALLOC_REMAP
780 bool
781 depends on NUMA
782 default y
784 config ARCH_DISCONTIGMEM_ENABLE
785 def_bool y
786 depends on NUMA
788 config ARCH_DISCONTIGMEM_DEFAULT
789 def_bool y
790 depends on NUMA
792 config ARCH_SPARSEMEM_ENABLE
793 def_bool y
794 depends on NUMA
796 config ARCH_SELECT_MEMORY_MODEL
797 def_bool y
798 depends on ARCH_SPARSEMEM_ENABLE
800 source "mm/Kconfig"
802 config HAVE_ARCH_EARLY_PFN_TO_NID
803 bool
804 default y
805 depends on NUMA
807 config HIGHPTE
808 bool "Allocate 3rd-level pagetables from highmem"
809 depends on HIGHMEM4G || HIGHMEM64G
810 help
811 The VM uses one page table entry for each page of physical memory.
812 For systems with a lot of RAM, this can be wasteful of precious
813 low memory. Setting this option will put user-space page table
814 entries in high memory.
816 config MATH_EMULATION
817 bool "Math emulation"
818 ---help---
819 Linux can emulate a math coprocessor (used for floating point
820 operations) if you don't have one. 486DX and Pentium processors have
821 a math coprocessor built in, 486SX and 386 do not, unless you added
822 a 487DX or 387, respectively. (The messages during boot time can
823 give you some hints here ["man dmesg"].) Everyone needs either a
824 coprocessor or this emulation.
826 If you don't have a math coprocessor, you need to say Y here; if you
827 say Y here even though you have a coprocessor, the coprocessor will
828 be used nevertheless. (This behavior can be changed with the kernel
829 command line option "no387", which comes handy if your coprocessor
830 is broken. Try "man bootparam" or see the documentation of your boot
831 loader (lilo or loadlin) about how to pass options to the kernel at
832 boot time.) This means that it is a good idea to say Y here if you
833 intend to use this kernel on different machines.
835 More information about the internals of the Linux math coprocessor
836 emulation can be found in <file:arch/i386/math-emu/README>.
838 If you are not sure, say Y; apart from resulting in a 66 KB bigger
839 kernel, it won't hurt.
841 config MTRR
842 bool "MTRR (Memory Type Range Register) support"
843 ---help---
844 On Intel P6 family processors (Pentium Pro, Pentium II and later)
845 the Memory Type Range Registers (MTRRs) may be used to control
846 processor access to memory ranges. This is most useful if you have
847 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
848 allows bus write transfers to be combined into a larger transfer
849 before bursting over the PCI/AGP bus. This can increase performance
850 of image write operations 2.5 times or more. Saying Y here creates a
851 /proc/mtrr file which may be used to manipulate your processor's
852 MTRRs. Typically the X server should use this.
854 This code has a reasonably generic interface so that similar
855 control registers on other processors can be easily supported
856 as well:
858 The Cyrix 6x86, 6x86MX and M II processors have Address Range
859 Registers (ARRs) which provide a similar functionality to MTRRs. For
860 these, the ARRs are used to emulate the MTRRs.
861 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
862 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
863 write-combining. All of these processors are supported by this code
864 and it makes sense to say Y here if you have one of them.
866 Saying Y here also fixes a problem with buggy SMP BIOSes which only
867 set the MTRRs for the boot CPU and not for the secondary CPUs. This
868 can lead to all sorts of problems, so it's good to say Y here.
870 You can safely say Y even if your machine doesn't have MTRRs, you'll
871 just add about 9 KB to your kernel.
873 See <file:Documentation/mtrr.txt> for more information.
875 config EFI
876 bool "Boot from EFI support (EXPERIMENTAL)"
877 depends on ACPI
878 default n
879 ---help---
880 This enables the the kernel to boot on EFI platforms using
881 system configuration information passed to it from the firmware.
882 This also enables the kernel to use any EFI runtime services that are
883 available (such as the EFI variable services).
885 This option is only useful on systems that have EFI firmware
886 and will result in a kernel image that is ~8k larger. In addition,
887 you must use the latest ELILO loader available at
888 <http://elilo.sourceforge.net> in order to take advantage of
889 kernel initialization using EFI information (neither GRUB nor LILO know
890 anything about EFI). However, even with this option, the resultant
891 kernel should continue to boot on existing non-EFI platforms.
893 config IRQBALANCE
894 bool "Enable kernel irq balancing"
895 depends on SMP && X86_IO_APIC
896 default y
897 help
898 The default yes will allow the kernel to do irq load balancing.
899 Saying no will keep the kernel from doing irq load balancing.
901 config HAVE_DEC_LOCK
902 bool
903 depends on (SMP || PREEMPT) && X86_CMPXCHG
904 default y
906 # turning this on wastes a bunch of space.
907 # Summit needs it only when NUMA is on
908 config BOOT_IOREMAP
909 bool
910 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
911 default y
913 config REGPARM
914 bool "Use register arguments (EXPERIMENTAL)"
915 depends on EXPERIMENTAL
916 default n
917 help
918 Compile the kernel with -mregparm=3. This uses a different ABI
919 and passes the first three arguments of a function call in registers.
920 This will probably break binary only modules.
922 This feature is only enabled for gcc-3.0 and later - earlier compilers
923 generate incorrect output with certain kernel constructs when
924 -mregparm=3 is used.
926 config SECCOMP
927 bool "Enable seccomp to safely compute untrusted bytecode"
928 depends on PROC_FS
929 default y
930 help
931 This kernel feature is useful for number crunching applications
932 that may need to compute untrusted bytecode during their
933 execution. By using pipes or other transports made available to
934 the process as file descriptors supporting the read/write
935 syscalls, it's possible to isolate those applications in
936 their own address space using seccomp. Once seccomp is
937 enabled via /proc/<pid>/seccomp, it cannot be disabled
938 and the task is only allowed to execute a few safe syscalls
939 defined by each seccomp mode.
941 If unsure, say Y. Only embedded should say N here.
943 source kernel/Kconfig.hz
945 config PHYSICAL_START
946 hex "Physical address where the kernel is loaded" if EMBEDDED
947 default "0x100000"
948 help
949 This gives the physical address where the kernel is loaded.
950 Primarily used in the case of kexec on panic where the
951 fail safe kernel needs to run at a different address than
952 the panic-ed kernel.
954 Don't change this unless you know what you are doing.
956 config KEXEC
957 bool "kexec system call (EXPERIMENTAL)"
958 depends on EXPERIMENTAL
959 help
960 kexec is a system call that implements the ability to shutdown your
961 current kernel, and to start another kernel. It is like a reboot
962 but it is indepedent of the system firmware. And like a reboot
963 you can start any kernel with it, not just Linux.
965 The name comes from the similiarity to the exec system call.
967 It is an ongoing process to be certain the hardware in a machine
968 is properly shutdown, so do not be surprised if this code does not
969 initially work for you. It may help to enable device hotplugging
970 support. As of this writing the exact hardware interface is
971 strongly in flux, so no good recommendation can be made.
973 config CRASH_DUMP
974 bool "kernel crash dumps (EXPERIMENTAL)"
975 depends on EMBEDDED
976 depends on EXPERIMENTAL
977 depends on HIGHMEM
978 help
979 Generate crash dump after being started by kexec.
980 endmenu
983 menu "Power management options (ACPI, APM)"
984 depends on !X86_VOYAGER
986 source kernel/power/Kconfig
988 source "drivers/acpi/Kconfig"
990 menu "APM (Advanced Power Management) BIOS Support"
991 depends on PM && !X86_VISWS
993 config APM
994 tristate "APM (Advanced Power Management) BIOS support"
995 depends on PM
996 ---help---
997 APM is a BIOS specification for saving power using several different
998 techniques. This is mostly useful for battery powered laptops with
999 APM compliant BIOSes. If you say Y here, the system time will be
1000 reset after a RESUME operation, the /proc/apm device will provide
1001 battery status information, and user-space programs will receive
1002 notification of APM "events" (e.g. battery status change).
1004 If you select "Y" here, you can disable actual use of the APM
1005 BIOS by passing the "apm=off" option to the kernel at boot time.
1007 Note that the APM support is almost completely disabled for
1008 machines with more than one CPU.
1010 In order to use APM, you will need supporting software. For location
1011 and more information, read <file:Documentation/pm.txt> and the
1012 Battery Powered Linux mini-HOWTO, available from
1013 <http://www.tldp.org/docs.html#howto>.
1015 This driver does not spin down disk drives (see the hdparm(8)
1016 manpage ("man 8 hdparm") for that), and it doesn't turn off
1017 VESA-compliant "green" monitors.
1019 This driver does not support the TI 4000M TravelMate and the ACER
1020 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1021 desktop machines also don't have compliant BIOSes, and this driver
1022 may cause those machines to panic during the boot phase.
1024 Generally, if you don't have a battery in your machine, there isn't
1025 much point in using this driver and you should say N. If you get
1026 random kernel OOPSes or reboots that don't seem to be related to
1027 anything, try disabling/enabling this option (or disabling/enabling
1028 APM in your BIOS).
1030 Some other things you should try when experiencing seemingly random,
1031 "weird" problems:
1033 1) make sure that you have enough swap space and that it is
1034 enabled.
1035 2) pass the "no-hlt" option to the kernel
1036 3) switch on floating point emulation in the kernel and pass
1037 the "no387" option to the kernel
1038 4) pass the "floppy=nodma" option to the kernel
1039 5) pass the "mem=4M" option to the kernel (thereby disabling
1040 all but the first 4 MB of RAM)
1041 6) make sure that the CPU is not over clocked.
1042 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1043 8) disable the cache from your BIOS settings
1044 9) install a fan for the video card or exchange video RAM
1045 10) install a better fan for the CPU
1046 11) exchange RAM chips
1047 12) exchange the motherboard.
1049 To compile this driver as a module, choose M here: the
1050 module will be called apm.
1052 config APM_IGNORE_USER_SUSPEND
1053 bool "Ignore USER SUSPEND"
1054 depends on APM
1055 help
1056 This option will ignore USER SUSPEND requests. On machines with a
1057 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1058 series notebooks, it is necessary to say Y because of a BIOS bug.
1060 config APM_DO_ENABLE
1061 bool "Enable PM at boot time"
1062 depends on APM
1063 ---help---
1064 Enable APM features at boot time. From page 36 of the APM BIOS
1065 specification: "When disabled, the APM BIOS does not automatically
1066 power manage devices, enter the Standby State, enter the Suspend
1067 State, or take power saving steps in response to CPU Idle calls."
1068 This driver will make CPU Idle calls when Linux is idle (unless this
1069 feature is turned off -- see "Do CPU IDLE calls", below). This
1070 should always save battery power, but more complicated APM features
1071 will be dependent on your BIOS implementation. You may need to turn
1072 this option off if your computer hangs at boot time when using APM
1073 support, or if it beeps continuously instead of suspending. Turn
1074 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1075 T400CDT. This is off by default since most machines do fine without
1076 this feature.
1078 config APM_CPU_IDLE
1079 bool "Make CPU Idle calls when idle"
1080 depends on APM
1081 help
1082 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1083 On some machines, this can activate improved power savings, such as
1084 a slowed CPU clock rate, when the machine is idle. These idle calls
1085 are made after the idle loop has run for some length of time (e.g.,
1086 333 mS). On some machines, this will cause a hang at boot time or
1087 whenever the CPU becomes idle. (On machines with more than one CPU,
1088 this option does nothing.)
1090 config APM_DISPLAY_BLANK
1091 bool "Enable console blanking using APM"
1092 depends on APM
1093 help
1094 Enable console blanking using the APM. Some laptops can use this to
1095 turn off the LCD backlight when the screen blanker of the Linux
1096 virtual console blanks the screen. Note that this is only used by
1097 the virtual console screen blanker, and won't turn off the backlight
1098 when using the X Window system. This also doesn't have anything to
1099 do with your VESA-compliant power-saving monitor. Further, this
1100 option doesn't work for all laptops -- it might not turn off your
1101 backlight at all, or it might print a lot of errors to the console,
1102 especially if you are using gpm.
1104 config APM_RTC_IS_GMT
1105 bool "RTC stores time in GMT"
1106 depends on APM
1107 help
1108 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1109 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1110 stores localtime.
1112 It is in fact recommended to store GMT in your RTC, because then you
1113 don't have to worry about daylight savings time changes. The only
1114 reason not to use GMT in your RTC is if you also run a broken OS
1115 that doesn't understand GMT.
1117 config APM_ALLOW_INTS
1118 bool "Allow interrupts during APM BIOS calls"
1119 depends on APM
1120 help
1121 Normally we disable external interrupts while we are making calls to
1122 the APM BIOS as a measure to lessen the effects of a badly behaving
1123 BIOS implementation. The BIOS should reenable interrupts if it
1124 needs to. Unfortunately, some BIOSes do not -- especially those in
1125 many of the newer IBM Thinkpads. If you experience hangs when you
1126 suspend, try setting this to Y. Otherwise, say N.
1128 config APM_REAL_MODE_POWER_OFF
1129 bool "Use real mode APM BIOS call to power off"
1130 depends on APM
1131 help
1132 Use real mode APM BIOS calls to switch off the computer. This is
1133 a work-around for a number of buggy BIOSes. Switch this option on if
1134 your computer crashes instead of powering off properly.
1136 endmenu
1138 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1140 endmenu
1142 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1144 config PCI
1145 bool "PCI support" if !X86_VISWS
1146 depends on !X86_VOYAGER
1147 default y if X86_VISWS
1148 help
1149 Find out whether you have a PCI motherboard. PCI is the name of a
1150 bus system, i.e. the way the CPU talks to the other stuff inside
1151 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1152 VESA. If you have PCI, say Y, otherwise N.
1154 The PCI-HOWTO, available from
1155 <http://www.tldp.org/docs.html#howto>, contains valuable
1156 information about which PCI hardware does work under Linux and which
1157 doesn't.
1159 choice
1160 prompt "PCI access mode"
1161 depends on PCI && !X86_VISWS
1162 default PCI_GOANY
1163 ---help---
1164 On PCI systems, the BIOS can be used to detect the PCI devices and
1165 determine their configuration. However, some old PCI motherboards
1166 have BIOS bugs and may crash if this is done. Also, some embedded
1167 PCI-based systems don't have any BIOS at all. Linux can also try to
1168 detect the PCI hardware directly without using the BIOS.
1170 With this option, you can specify how Linux should detect the
1171 PCI devices. If you choose "BIOS", the BIOS will be used,
1172 if you choose "Direct", the BIOS won't be used, and if you
1173 choose "MMConfig", then PCI Express MMCONFIG will be used.
1174 If you choose "Any", the kernel will try MMCONFIG, then the
1175 direct access method and falls back to the BIOS if that doesn't
1176 work. If unsure, go with the default, which is "Any".
1178 config PCI_GOBIOS
1179 bool "BIOS"
1181 config PCI_GOMMCONFIG
1182 bool "MMConfig"
1184 config PCI_GODIRECT
1185 bool "Direct"
1187 config PCI_GOANY
1188 bool "Any"
1190 endchoice
1192 config PCI_BIOS
1193 bool
1194 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1195 default y
1197 config PCI_DIRECT
1198 bool
1199 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1200 default y
1202 config PCI_MMCONFIG
1203 bool
1204 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1205 select ACPI_BOOT
1206 default y
1208 source "drivers/pci/pcie/Kconfig"
1210 source "drivers/pci/Kconfig"
1212 config ISA_DMA_API
1213 bool
1214 default y
1216 config ISA
1217 bool "ISA support"
1218 depends on !(X86_VOYAGER || X86_VISWS)
1219 help
1220 Find out whether you have ISA slots on your motherboard. ISA is the
1221 name of a bus system, i.e. the way the CPU talks to the other stuff
1222 inside your box. Other bus systems are PCI, EISA, MicroChannel
1223 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1224 newer boards don't support it. If you have ISA, say Y, otherwise N.
1226 config EISA
1227 bool "EISA support"
1228 depends on ISA
1229 ---help---
1230 The Extended Industry Standard Architecture (EISA) bus was
1231 developed as an open alternative to the IBM MicroChannel bus.
1233 The EISA bus provided some of the features of the IBM MicroChannel
1234 bus while maintaining backward compatibility with cards made for
1235 the older ISA bus. The EISA bus saw limited use between 1988 and
1236 1995 when it was made obsolete by the PCI bus.
1238 Say Y here if you are building a kernel for an EISA-based machine.
1240 Otherwise, say N.
1242 source "drivers/eisa/Kconfig"
1244 config MCA
1245 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1246 default y if X86_VOYAGER
1247 help
1248 MicroChannel Architecture is found in some IBM PS/2 machines and
1249 laptops. It is a bus system similar to PCI or ISA. See
1250 <file:Documentation/mca.txt> (and especially the web page given
1251 there) before attempting to build an MCA bus kernel.
1253 source "drivers/mca/Kconfig"
1255 config SCx200
1256 tristate "NatSemi SCx200 support"
1257 depends on !X86_VOYAGER
1258 help
1259 This provides basic support for the National Semiconductor SCx200
1260 processor. Right now this is just a driver for the GPIO pins.
1262 If you don't know what to do here, say N.
1264 This support is also available as a module. If compiled as a
1265 module, it will be called scx200.
1267 config HOTPLUG_CPU
1268 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
1269 depends on SMP && HOTPLUG && EXPERIMENTAL
1270 ---help---
1271 Say Y here to experiment with turning CPUs off and on. CPUs
1272 can be controlled through /sys/devices/system/cpu.
1274 Say N.
1276 source "drivers/pcmcia/Kconfig"
1278 source "drivers/pci/hotplug/Kconfig"
1280 endmenu
1282 menu "Executable file formats"
1284 source "fs/Kconfig.binfmt"
1286 endmenu
1288 source "drivers/Kconfig"
1290 source "fs/Kconfig"
1292 source "arch/i386/oprofile/Kconfig"
1294 source "arch/i386/Kconfig.debug"
1296 source "security/Kconfig"
1298 source "crypto/Kconfig"
1300 source "lib/Kconfig"
1302 #
1303 # Use the generic interrupt handling code in kernel/irq/:
1304 #
1305 config GENERIC_HARDIRQS
1306 bool
1307 default y
1309 config GENERIC_IRQ_PROBE
1310 bool
1311 default y
1313 config X86_SMP
1314 bool
1315 depends on SMP && !X86_VOYAGER
1316 default y
1318 config X86_HT
1319 bool
1320 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1321 default y
1323 config X86_BIOS_REBOOT
1324 bool
1325 depends on !(X86_VISWS || X86_VOYAGER)
1326 default y
1328 config X86_TRAMPOLINE
1329 bool
1330 depends on X86_SMP || (X86_VOYAGER && SMP)
1331 default y
1333 config PC
1334 bool
1335 depends on X86 && !EMBEDDED
1336 default y