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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 SEMAPHORE_SLEEPERS
18 bool
19 default y
21 config MMU
22 bool
23 default y
25 config SBUS
26 bool
28 config UID16
29 bool
30 default y
32 config GENERIC_ISA_DMA
33 bool
34 default y
36 config GENERIC_IOMAP
37 bool
38 default y
40 source "init/Kconfig"
42 menu "Processor type and features"
44 choice
45 prompt "Subarchitecture Type"
46 default X86_PC
48 config X86_PC
49 bool "PC-compatible"
50 help
51 Choose this option if your computer is a standard PC or compatible.
53 config X86_ELAN
54 bool "AMD Elan"
55 help
56 Select this for an AMD Elan processor.
58 Do not use this option for K6/Athlon/Opteron processors!
60 If unsure, choose "PC-compatible" instead.
62 config X86_VOYAGER
63 bool "Voyager (NCR)"
64 help
65 Voyager is an MCA-based 32-way capable SMP architecture proprietary
66 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
68 *** WARNING ***
70 If you do not specifically know you have a Voyager based machine,
71 say N here, otherwise the kernel you build will not be bootable.
73 config X86_NUMAQ
74 bool "NUMAQ (IBM/Sequent)"
75 select NUMA
76 help
77 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
78 multiquad box. This changes the way that processors are bootstrapped,
79 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
80 You will need a new lynxer.elf file to flash your firmware with - send
81 email to <Martin.Bligh@us.ibm.com>.
83 config X86_SUMMIT
84 bool "Summit/EXA (IBM x440)"
85 depends on SMP
86 help
87 This option is needed for IBM systems that use the Summit/EXA chipset.
88 In particular, it is needed for the x440.
90 If you don't have one of these computers, you should say N here.
92 config X86_BIGSMP
93 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
94 depends on SMP
95 help
96 This option is needed for the systems that have more than 8 CPUs
97 and if the system is not of any sub-arch type above.
99 If you don't have such a system, you should say N here.
101 config X86_VISWS
102 bool "SGI 320/540 (Visual Workstation)"
103 help
104 The SGI Visual Workstation series is an IA32-based workstation
105 based on SGI systems chips with some legacy PC hardware attached.
107 Say Y here to create a kernel to run on the SGI 320 or 540.
109 A kernel compiled for the Visual Workstation will not run on PCs
110 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
112 config X86_GENERICARCH
113 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
114 depends on SMP
115 help
116 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
117 It is intended for a generic binary kernel.
119 config X86_ES7000
120 bool "Support for Unisys ES7000 IA32 series"
121 depends on SMP
122 help
123 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
124 supposed to run on an IA32-based Unisys ES7000 system.
125 Only choose this option if you have such a system, otherwise you
126 should say N here.
128 endchoice
130 config ACPI_SRAT
131 bool
132 default y
133 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
135 config X86_SUMMIT_NUMA
136 bool
137 default y
138 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
140 config X86_CYCLONE_TIMER
141 bool
142 default y
143 depends on X86_SUMMIT || X86_GENERICARCH
145 config ES7000_CLUSTERED_APIC
146 bool
147 default y
148 depends on SMP && X86_ES7000 && MPENTIUMIII
150 if !X86_ELAN
152 choice
153 prompt "Processor family"
154 default M686
156 config M386
157 bool "386"
158 ---help---
159 This is the processor type of your CPU. This information is used for
160 optimizing purposes. In order to compile a kernel that can run on
161 all x86 CPU types (albeit not optimally fast), you can specify
162 "386" here.
164 The kernel will not necessarily run on earlier architectures than
165 the one you have chosen, e.g. a Pentium optimized kernel will run on
166 a PPro, but not necessarily on a i486.
168 Here are the settings recommended for greatest speed:
169 - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
170 486DLC/DLC2, UMC 486SX-S and NexGen Nx586. Only "386" kernels
171 will run on a 386 class machine.
172 - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
173 SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
174 - "586" for generic Pentium CPUs lacking the TSC
175 (time stamp counter) register.
176 - "Pentium-Classic" for the Intel Pentium.
177 - "Pentium-MMX" for the Intel Pentium MMX.
178 - "Pentium-Pro" for the Intel Pentium Pro.
179 - "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
180 - "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
181 - "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
182 - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
183 - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
184 - "Crusoe" for the Transmeta Crusoe series.
185 - "Efficeon" for the Transmeta Efficeon series.
186 - "Winchip-C6" for original IDT Winchip.
187 - "Winchip-2" for IDT Winchip 2.
188 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
189 - "GeodeGX1" for Geode GX1 (Cyrix MediaGX).
190 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
191 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
193 If you don't know what to do, choose "386".
195 config M486
196 bool "486"
197 help
198 Select this for a 486 series processor, either Intel or one of the
199 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
200 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
201 U5S.
203 config M586
204 bool "586/K5/5x86/6x86/6x86MX"
205 help
206 Select this for an 586 or 686 series processor such as the AMD K5,
207 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
208 assume the RDTSC (Read Time Stamp Counter) instruction.
210 config M586TSC
211 bool "Pentium-Classic"
212 help
213 Select this for a Pentium Classic processor with the RDTSC (Read
214 Time Stamp Counter) instruction for benchmarking.
216 config M586MMX
217 bool "Pentium-MMX"
218 help
219 Select this for a Pentium with the MMX graphics/multimedia
220 extended instructions.
222 config M686
223 bool "Pentium-Pro"
224 help
225 Select this for Intel Pentium Pro chips. This enables the use of
226 Pentium Pro extended instructions, and disables the init-time guard
227 against the f00f bug found in earlier Pentiums.
229 config MPENTIUMII
230 bool "Pentium-II/Celeron(pre-Coppermine)"
231 help
232 Select this for Intel chips based on the Pentium-II and
233 pre-Coppermine Celeron core. This option enables an unaligned
234 copy optimization, compiles the kernel with optimization flags
235 tailored for the chip, and applies any applicable Pentium Pro
236 optimizations.
238 config MPENTIUMIII
239 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
240 help
241 Select this for Intel chips based on the Pentium-III and
242 Celeron-Coppermine core. This option enables use of some
243 extended prefetch instructions in addition to the Pentium II
244 extensions.
246 config MPENTIUMM
247 bool "Pentium M"
248 help
249 Select this for Intel Pentium M (not Pentium-4 M)
250 notebook chips.
252 config MPENTIUM4
253 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
254 help
255 Select this for Intel Pentium 4 chips. This includes the
256 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
257 (not Pentium M) chips. This option enables compile flags
258 optimized for the chip, uses the correct cache shift, and
259 applies any applicable Pentium III optimizations.
261 config MK6
262 bool "K6/K6-II/K6-III"
263 help
264 Select this for an AMD K6-family processor. Enables use of
265 some extended instructions, and passes appropriate optimization
266 flags to GCC.
268 config MK7
269 bool "Athlon/Duron/K7"
270 help
271 Select this for an AMD Athlon K7-family processor. Enables use of
272 some extended instructions, and passes appropriate optimization
273 flags to GCC.
275 config MK8
276 bool "Opteron/Athlon64/Hammer/K8"
277 help
278 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
279 use of some extended instructions, and passes appropriate optimization
280 flags to GCC.
282 config MCRUSOE
283 bool "Crusoe"
284 help
285 Select this for a Transmeta Crusoe processor. Treats the processor
286 like a 586 with TSC, and sets some GCC optimization flags (like a
287 Pentium Pro with no alignment requirements).
289 config MEFFICEON
290 bool "Efficeon"
291 help
292 Select this for a Transmeta Efficeon processor.
294 config MWINCHIPC6
295 bool "Winchip-C6"
296 help
297 Select this for an IDT Winchip C6 chip. Linux and GCC
298 treat this chip as a 586TSC with some extended instructions
299 and alignment requirements.
301 config MWINCHIP2
302 bool "Winchip-2"
303 help
304 Select this for an IDT Winchip-2. Linux and GCC
305 treat this chip as a 586TSC with some extended instructions
306 and alignment requirements.
308 config MWINCHIP3D
309 bool "Winchip-2A/Winchip-3"
310 help
311 Select this for an IDT Winchip-2A or 3. Linux and GCC
312 treat this chip as a 586TSC with some extended instructions
313 and alignment reqirements. Also enable out of order memory
314 stores for this CPU, which can increase performance of some
315 operations.
317 config MGEODEGX1
318 bool "GeodeGX1"
319 help
320 Select this for a Geode GX1 (Cyrix MediaGX) chip.
322 config MCYRIXIII
323 bool "CyrixIII/VIA-C3"
324 help
325 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
326 treat this chip as a generic 586. Whilst the CPU is 686 class,
327 it lacks the cmov extension which gcc assumes is present when
328 generating 686 code.
329 Note that Nehemiah (Model 9) and above will not boot with this
330 kernel due to them lacking the 3DNow! instructions used in earlier
331 incarnations of the CPU.
333 config MVIAC3_2
334 bool "VIA C3-2 (Nehemiah)"
335 help
336 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
337 of SSE and tells gcc to treat the CPU as a 686.
338 Note, this kernel will not boot on older (pre model 9) C3s.
340 endchoice
342 config X86_GENERIC
343 bool "Generic x86 support"
344 help
345 Instead of just including optimizations for the selected
346 x86 variant (e.g. PII, Crusoe or Athlon), include some more
347 generic optimizations as well. This will make the kernel
348 perform better on x86 CPUs other than that selected.
350 This is really intended for distributors who need more
351 generic optimizations.
353 endif
355 #
356 # Define implied options from the CPU selection here
357 #
358 config X86_CMPXCHG
359 bool
360 depends on !M386
361 default y
363 config X86_XADD
364 bool
365 depends on !M386
366 default y
368 config X86_L1_CACHE_SHIFT
369 int
370 default "7" if MPENTIUM4 || X86_GENERIC
371 default "4" if X86_ELAN || M486 || M386
372 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODEGX1
373 default "6" if MK7 || MK8 || MPENTIUMM
375 config RWSEM_GENERIC_SPINLOCK
376 bool
377 depends on M386
378 default y
380 config RWSEM_XCHGADD_ALGORITHM
381 bool
382 depends on !M386
383 default y
385 config GENERIC_CALIBRATE_DELAY
386 bool
387 default y
389 config X86_PPRO_FENCE
390 bool
391 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1
392 default y
394 config X86_F00F_BUG
395 bool
396 depends on M586MMX || M586TSC || M586 || M486 || M386
397 default y
399 config X86_WP_WORKS_OK
400 bool
401 depends on !M386
402 default y
404 config X86_INVLPG
405 bool
406 depends on !M386
407 default y
409 config X86_BSWAP
410 bool
411 depends on !M386
412 default y
414 config X86_POPAD_OK
415 bool
416 depends on !M386
417 default y
419 config X86_ALIGNMENT_16
420 bool
421 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
422 default y
424 config X86_GOOD_APIC
425 bool
426 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
427 default y
429 config X86_INTEL_USERCOPY
430 bool
431 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
432 default y
434 config X86_USE_PPRO_CHECKSUM
435 bool
436 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
437 default y
439 config X86_USE_3DNOW
440 bool
441 depends on MCYRIXIII || MK7
442 default y
444 config X86_OOSTORE
445 bool
446 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
447 default y
449 config HPET_TIMER
450 bool "HPET Timer Support"
451 help
452 This enables the use of the HPET for the kernel's internal timer.
453 HPET is the next generation timer replacing legacy 8254s.
454 You can safely choose Y here. However, HPET will only be
455 activated if the platform and the BIOS support this feature.
456 Otherwise the 8254 will be used for timing services.
458 Choose N to continue using the legacy 8254 timer.
460 config HPET_EMULATE_RTC
461 bool
462 depends on HPET_TIMER && RTC=y
463 default y
465 config SMP
466 bool "Symmetric multi-processing support"
467 ---help---
468 This enables support for systems with more than one CPU. If you have
469 a system with only one CPU, like most personal computers, say N. If
470 you have a system with more than one CPU, say Y.
472 If you say N here, the kernel will run on single and multiprocessor
473 machines, but will use only one CPU of a multiprocessor machine. If
474 you say Y here, the kernel will run on many, but not all,
475 singleprocessor machines. On a singleprocessor machine, the kernel
476 will run faster if you say N here.
478 Note that if you say Y here and choose architecture "586" or
479 "Pentium" under "Processor family", the kernel will not work on 486
480 architectures. Similarly, multiprocessor kernels for the "PPro"
481 architecture may not work on all Pentium based boards.
483 People using multiprocessor machines who say Y here should also say
484 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
485 Management" code will be disabled if you say Y here.
487 See also the <file:Documentation/smp.txt>,
488 <file:Documentation/i386/IO-APIC.txt>,
489 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
490 <http://www.tldp.org/docs.html#howto>.
492 If you don't know what to do here, say N.
494 config NR_CPUS
495 int "Maximum number of CPUs (2-255)"
496 range 2 255
497 depends on SMP
498 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
499 default "8"
500 help
501 This allows you to specify the maximum number of CPUs which this
502 kernel will support. The maximum supported value is 255 and the
503 minimum value which makes sense is 2.
505 This is purely to save memory - each supported CPU adds
506 approximately eight kilobytes to the kernel image.
508 config SCHED_SMT
509 bool "SMT (Hyperthreading) scheduler support"
510 depends on SMP
511 default off
512 help
513 SMT scheduler support improves the CPU scheduler's decision making
514 when dealing with Intel Pentium 4 chips with HyperThreading at a
515 cost of slightly increased overhead in some places. If unsure say
516 N here.
518 source "kernel/Kconfig.preempt"
520 config X86_UP_APIC
521 bool "Local APIC support on uniprocessors"
522 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
523 help
524 A local APIC (Advanced Programmable Interrupt Controller) is an
525 integrated interrupt controller in the CPU. If you have a single-CPU
526 system which has a processor with a local APIC, you can say Y here to
527 enable and use it. If you say Y here even though your machine doesn't
528 have a local APIC, then the kernel will still run with no slowdown at
529 all. The local APIC supports CPU-generated self-interrupts (timer,
530 performance counters), and the NMI watchdog which detects hard
531 lockups.
533 config X86_UP_IOAPIC
534 bool "IO-APIC support on uniprocessors"
535 depends on X86_UP_APIC
536 help
537 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
538 SMP-capable replacement for PC-style interrupt controllers. Most
539 SMP systems and many recent uniprocessor systems have one.
541 If you have a single-CPU system with an IO-APIC, you can say Y here
542 to use it. If you say Y here even though your machine doesn't have
543 an IO-APIC, then the kernel will still run with no slowdown at all.
545 config X86_LOCAL_APIC
546 bool
547 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
548 default y
550 config X86_IO_APIC
551 bool
552 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
553 default y
555 config X86_VISWS_APIC
556 bool
557 depends on X86_VISWS
558 default y
560 config X86_TSC
561 bool
562 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
563 default y
565 config X86_MCE
566 bool "Machine Check Exception"
567 depends on !X86_VOYAGER
568 ---help---
569 Machine Check Exception support allows the processor to notify the
570 kernel if it detects a problem (e.g. overheating, component failure).
571 The action the kernel takes depends on the severity of the problem,
572 ranging from a warning message on the console, to halting the machine.
573 Your processor must be a Pentium or newer to support this - check the
574 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
575 have a design flaw which leads to false MCE events - hence MCE is
576 disabled on all P5 processors, unless explicitly enabled with "mce"
577 as a boot argument. Similarly, if MCE is built in and creates a
578 problem on some new non-standard machine, you can boot with "nomce"
579 to disable it. MCE support simply ignores non-MCE processors like
580 the 386 and 486, so nearly everyone can say Y here.
582 config X86_MCE_NONFATAL
583 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
584 depends on X86_MCE
585 help
586 Enabling this feature starts a timer that triggers every 5 seconds which
587 will look at the machine check registers to see if anything happened.
588 Non-fatal problems automatically get corrected (but still logged).
589 Disable this if you don't want to see these messages.
590 Seeing the messages this option prints out may be indicative of dying hardware,
591 or out-of-spec (ie, overclocked) hardware.
592 This option only does something on certain CPUs.
593 (AMD Athlon/Duron and Intel Pentium 4)
595 config X86_MCE_P4THERMAL
596 bool "check for P4 thermal throttling interrupt."
597 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
598 help
599 Enabling this feature will cause a message to be printed when the P4
600 enters thermal throttling.
602 config TOSHIBA
603 tristate "Toshiba Laptop support"
604 ---help---
605 This adds a driver to safely access the System Management Mode of
606 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
607 not work on models with a Phoenix BIOS. The System Management Mode
608 is used to set the BIOS and power saving options on Toshiba portables.
610 For information on utilities to make use of this driver see the
611 Toshiba Linux utilities web site at:
612 <http://www.buzzard.org.uk/toshiba/>.
614 Say Y if you intend to run this kernel on a Toshiba portable.
615 Say N otherwise.
617 config I8K
618 tristate "Dell laptop support"
619 ---help---
620 This adds a driver to safely access the System Management Mode
621 of the CPU on the Dell Inspiron 8000. The System Management Mode
622 is used to read cpu temperature and cooling fan status and to
623 control the fans on the I8K portables.
625 This driver has been tested only on the Inspiron 8000 but it may
626 also work with other Dell laptops. You can force loading on other
627 models by passing the parameter `force=1' to the module. Use at
628 your own risk.
630 For information on utilities to make use of this driver see the
631 I8K Linux utilities web site at:
632 <http://people.debian.org/~dz/i8k/>
634 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
635 Say N otherwise.
637 config X86_REBOOTFIXUPS
638 bool "Enable X86 board specific fixups for reboot"
639 depends on X86
640 default n
641 ---help---
642 This enables chipset and/or board specific fixups to be done
643 in order to get reboot to work correctly. This is only needed on
644 some combinations of hardware and BIOS. The symptom, for which
645 this config is intended, is when reboot ends with a stalled/hung
646 system.
648 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
649 combination.
651 Say Y if you want to enable the fixup. Currently, it's safe to
652 enable this option even if you don't need it.
653 Say N otherwise.
655 config MICROCODE
656 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
657 ---help---
658 If you say Y here and also to "/dev file system support" in the
659 'File systems' section, you will be able to update the microcode on
660 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
661 Pentium III, Pentium 4, Xeon etc. You will obviously need the
662 actual microcode binary data itself which is not shipped with the
663 Linux kernel.
665 For latest news and information on obtaining all the required
666 ingredients for this driver, check:
667 <http://www.urbanmyth.org/microcode/>.
669 To compile this driver as a module, choose M here: the
670 module will be called microcode.
672 config X86_MSR
673 tristate "/dev/cpu/*/msr - Model-specific register support"
674 help
675 This device gives privileged processes access to the x86
676 Model-Specific Registers (MSRs). It is a character device with
677 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
678 MSR accesses are directed to a specific CPU on multi-processor
679 systems.
681 config X86_CPUID
682 tristate "/dev/cpu/*/cpuid - CPU information support"
683 help
684 This device gives processes access to the x86 CPUID instruction to
685 be executed on a specific processor. It is a character device
686 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
687 /dev/cpu/31/cpuid.
689 source "drivers/firmware/Kconfig"
691 choice
692 prompt "High Memory Support"
693 default NOHIGHMEM
695 config NOHIGHMEM
696 bool "off"
697 ---help---
698 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
699 However, the address space of 32-bit x86 processors is only 4
700 Gigabytes large. That means that, if you have a large amount of
701 physical memory, not all of it can be "permanently mapped" by the
702 kernel. The physical memory that's not permanently mapped is called
703 "high memory".
705 If you are compiling a kernel which will never run on a machine with
706 more than 1 Gigabyte total physical RAM, answer "off" here (default
707 choice and suitable for most users). This will result in a "3GB/1GB"
708 split: 3GB are mapped so that each process sees a 3GB virtual memory
709 space and the remaining part of the 4GB virtual memory space is used
710 by the kernel to permanently map as much physical memory as
711 possible.
713 If the machine has between 1 and 4 Gigabytes physical RAM, then
714 answer "4GB" here.
716 If more than 4 Gigabytes is used then answer "64GB" here. This
717 selection turns Intel PAE (Physical Address Extension) mode on.
718 PAE implements 3-level paging on IA32 processors. PAE is fully
719 supported by Linux, PAE mode is implemented on all recent Intel
720 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
721 then the kernel will not boot on CPUs that don't support PAE!
723 The actual amount of total physical memory will either be
724 auto detected or can be forced by using a kernel command line option
725 such as "mem=256M". (Try "man bootparam" or see the documentation of
726 your boot loader (lilo or loadlin) about how to pass options to the
727 kernel at boot time.)
729 If unsure, say "off".
731 config HIGHMEM4G
732 bool "4GB"
733 help
734 Select this if you have a 32-bit processor and between 1 and 4
735 gigabytes of physical RAM.
737 config HIGHMEM64G
738 bool "64GB"
739 help
740 Select this if you have a 32-bit processor and more than 4
741 gigabytes of physical RAM.
743 endchoice
745 config HIGHMEM
746 bool
747 depends on HIGHMEM64G || HIGHMEM4G
748 default y
750 config X86_PAE
751 bool
752 depends on HIGHMEM64G
753 default y
755 # Common NUMA Features
756 config NUMA
757 bool "Numa Memory Allocation and Scheduler Support"
758 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
759 default n if X86_PC
760 default y if (X86_NUMAQ || X86_SUMMIT)
761 select SPARSEMEM_STATIC
763 # Need comments to help the hapless user trying to turn on NUMA support
764 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
765 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
767 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
768 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
770 config HAVE_ARCH_BOOTMEM_NODE
771 bool
772 depends on NUMA
773 default y
775 config ARCH_HAVE_MEMORY_PRESENT
776 bool
777 depends on DISCONTIGMEM
778 default y
780 config NEED_NODE_MEMMAP_SIZE
781 bool
782 depends on DISCONTIGMEM || SPARSEMEM
783 default y
785 config HAVE_ARCH_ALLOC_REMAP
786 bool
787 depends on NUMA
788 default y
790 config ARCH_DISCONTIGMEM_ENABLE
791 def_bool y
792 depends on NUMA
794 config ARCH_DISCONTIGMEM_DEFAULT
795 def_bool y
796 depends on NUMA
798 config ARCH_SPARSEMEM_ENABLE
799 def_bool y
800 depends on NUMA
802 config ARCH_SELECT_MEMORY_MODEL
803 def_bool y
804 depends on ARCH_SPARSEMEM_ENABLE
806 source "mm/Kconfig"
808 config HAVE_ARCH_EARLY_PFN_TO_NID
809 bool
810 default y
811 depends on NUMA
813 config HIGHPTE
814 bool "Allocate 3rd-level pagetables from highmem"
815 depends on HIGHMEM4G || HIGHMEM64G
816 help
817 The VM uses one page table entry for each page of physical memory.
818 For systems with a lot of RAM, this can be wasteful of precious
819 low memory. Setting this option will put user-space page table
820 entries in high memory.
822 config MATH_EMULATION
823 bool "Math emulation"
824 ---help---
825 Linux can emulate a math coprocessor (used for floating point
826 operations) if you don't have one. 486DX and Pentium processors have
827 a math coprocessor built in, 486SX and 386 do not, unless you added
828 a 487DX or 387, respectively. (The messages during boot time can
829 give you some hints here ["man dmesg"].) Everyone needs either a
830 coprocessor or this emulation.
832 If you don't have a math coprocessor, you need to say Y here; if you
833 say Y here even though you have a coprocessor, the coprocessor will
834 be used nevertheless. (This behavior can be changed with the kernel
835 command line option "no387", which comes handy if your coprocessor
836 is broken. Try "man bootparam" or see the documentation of your boot
837 loader (lilo or loadlin) about how to pass options to the kernel at
838 boot time.) This means that it is a good idea to say Y here if you
839 intend to use this kernel on different machines.
841 More information about the internals of the Linux math coprocessor
842 emulation can be found in <file:arch/i386/math-emu/README>.
844 If you are not sure, say Y; apart from resulting in a 66 KB bigger
845 kernel, it won't hurt.
847 config MTRR
848 bool "MTRR (Memory Type Range Register) support"
849 ---help---
850 On Intel P6 family processors (Pentium Pro, Pentium II and later)
851 the Memory Type Range Registers (MTRRs) may be used to control
852 processor access to memory ranges. This is most useful if you have
853 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
854 allows bus write transfers to be combined into a larger transfer
855 before bursting over the PCI/AGP bus. This can increase performance
856 of image write operations 2.5 times or more. Saying Y here creates a
857 /proc/mtrr file which may be used to manipulate your processor's
858 MTRRs. Typically the X server should use this.
860 This code has a reasonably generic interface so that similar
861 control registers on other processors can be easily supported
862 as well:
864 The Cyrix 6x86, 6x86MX and M II processors have Address Range
865 Registers (ARRs) which provide a similar functionality to MTRRs. For
866 these, the ARRs are used to emulate the MTRRs.
867 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
868 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
869 write-combining. All of these processors are supported by this code
870 and it makes sense to say Y here if you have one of them.
872 Saying Y here also fixes a problem with buggy SMP BIOSes which only
873 set the MTRRs for the boot CPU and not for the secondary CPUs. This
874 can lead to all sorts of problems, so it's good to say Y here.
876 You can safely say Y even if your machine doesn't have MTRRs, you'll
877 just add about 9 KB to your kernel.
879 See <file:Documentation/mtrr.txt> for more information.
881 config EFI
882 bool "Boot from EFI support (EXPERIMENTAL)"
883 depends on ACPI
884 default n
885 ---help---
886 This enables the the kernel to boot on EFI platforms using
887 system configuration information passed to it from the firmware.
888 This also enables the kernel to use any EFI runtime services that are
889 available (such as the EFI variable services).
891 This option is only useful on systems that have EFI firmware
892 and will result in a kernel image that is ~8k larger. In addition,
893 you must use the latest ELILO loader available at
894 <http://elilo.sourceforge.net> in order to take advantage of
895 kernel initialization using EFI information (neither GRUB nor LILO know
896 anything about EFI). However, even with this option, the resultant
897 kernel should continue to boot on existing non-EFI platforms.
899 config IRQBALANCE
900 bool "Enable kernel irq balancing"
901 depends on SMP && X86_IO_APIC
902 default y
903 help
904 The default yes will allow the kernel to do irq load balancing.
905 Saying no will keep the kernel from doing irq load balancing.
907 config HAVE_DEC_LOCK
908 bool
909 depends on (SMP || PREEMPT) && X86_CMPXCHG
910 default y
912 # turning this on wastes a bunch of space.
913 # Summit needs it only when NUMA is on
914 config BOOT_IOREMAP
915 bool
916 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
917 default y
919 config REGPARM
920 bool "Use register arguments (EXPERIMENTAL)"
921 depends on EXPERIMENTAL
922 default n
923 help
924 Compile the kernel with -mregparm=3. This uses a different ABI
925 and passes the first three arguments of a function call in registers.
926 This will probably break binary only modules.
928 This feature is only enabled for gcc-3.0 and later - earlier compilers
929 generate incorrect output with certain kernel constructs when
930 -mregparm=3 is used.
932 config SECCOMP
933 bool "Enable seccomp to safely compute untrusted bytecode"
934 depends on PROC_FS
935 default y
936 help
937 This kernel feature is useful for number crunching applications
938 that may need to compute untrusted bytecode during their
939 execution. By using pipes or other transports made available to
940 the process as file descriptors supporting the read/write
941 syscalls, it's possible to isolate those applications in
942 their own address space using seccomp. Once seccomp is
943 enabled via /proc/<pid>/seccomp, it cannot be disabled
944 and the task is only allowed to execute a few safe syscalls
945 defined by each seccomp mode.
947 If unsure, say Y. Only embedded should say N here.
949 source kernel/Kconfig.hz
951 config PHYSICAL_START
952 hex "Physical address where the kernel is loaded" if EMBEDDED
953 default "0x100000"
954 help
955 This gives the physical address where the kernel is loaded.
956 Primarily used in the case of kexec on panic where the
957 fail safe kernel needs to run at a different address than
958 the panic-ed kernel.
960 Don't change this unless you know what you are doing.
962 config KEXEC
963 bool "kexec system call (EXPERIMENTAL)"
964 depends on EXPERIMENTAL
965 help
966 kexec is a system call that implements the ability to shutdown your
967 current kernel, and to start another kernel. It is like a reboot
968 but it is indepedent of the system firmware. And like a reboot
969 you can start any kernel with it, not just Linux.
971 The name comes from the similiarity to the exec system call.
973 It is an ongoing process to be certain the hardware in a machine
974 is properly shutdown, so do not be surprised if this code does not
975 initially work for you. It may help to enable device hotplugging
976 support. As of this writing the exact hardware interface is
977 strongly in flux, so no good recommendation can be made.
979 config CRASH_DUMP
980 bool "kernel crash dumps (EXPERIMENTAL)"
981 depends on EMBEDDED
982 depends on EXPERIMENTAL
983 depends on HIGHMEM
984 help
985 Generate crash dump after being started by kexec.
986 endmenu
989 menu "Power management options (ACPI, APM)"
990 depends on !X86_VOYAGER
992 source kernel/power/Kconfig
994 source "drivers/acpi/Kconfig"
996 menu "APM (Advanced Power Management) BIOS Support"
997 depends on PM && !X86_VISWS
999 config APM
1000 tristate "APM (Advanced Power Management) BIOS support"
1001 depends on PM
1002 ---help---
1003 APM is a BIOS specification for saving power using several different
1004 techniques. This is mostly useful for battery powered laptops with
1005 APM compliant BIOSes. If you say Y here, the system time will be
1006 reset after a RESUME operation, the /proc/apm device will provide
1007 battery status information, and user-space programs will receive
1008 notification of APM "events" (e.g. battery status change).
1010 If you select "Y" here, you can disable actual use of the APM
1011 BIOS by passing the "apm=off" option to the kernel at boot time.
1013 Note that the APM support is almost completely disabled for
1014 machines with more than one CPU.
1016 In order to use APM, you will need supporting software. For location
1017 and more information, read <file:Documentation/pm.txt> and the
1018 Battery Powered Linux mini-HOWTO, available from
1019 <http://www.tldp.org/docs.html#howto>.
1021 This driver does not spin down disk drives (see the hdparm(8)
1022 manpage ("man 8 hdparm") for that), and it doesn't turn off
1023 VESA-compliant "green" monitors.
1025 This driver does not support the TI 4000M TravelMate and the ACER
1026 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1027 desktop machines also don't have compliant BIOSes, and this driver
1028 may cause those machines to panic during the boot phase.
1030 Generally, if you don't have a battery in your machine, there isn't
1031 much point in using this driver and you should say N. If you get
1032 random kernel OOPSes or reboots that don't seem to be related to
1033 anything, try disabling/enabling this option (or disabling/enabling
1034 APM in your BIOS).
1036 Some other things you should try when experiencing seemingly random,
1037 "weird" problems:
1039 1) make sure that you have enough swap space and that it is
1040 enabled.
1041 2) pass the "no-hlt" option to the kernel
1042 3) switch on floating point emulation in the kernel and pass
1043 the "no387" option to the kernel
1044 4) pass the "floppy=nodma" option to the kernel
1045 5) pass the "mem=4M" option to the kernel (thereby disabling
1046 all but the first 4 MB of RAM)
1047 6) make sure that the CPU is not over clocked.
1048 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1049 8) disable the cache from your BIOS settings
1050 9) install a fan for the video card or exchange video RAM
1051 10) install a better fan for the CPU
1052 11) exchange RAM chips
1053 12) exchange the motherboard.
1055 To compile this driver as a module, choose M here: the
1056 module will be called apm.
1058 config APM_IGNORE_USER_SUSPEND
1059 bool "Ignore USER SUSPEND"
1060 depends on APM
1061 help
1062 This option will ignore USER SUSPEND requests. On machines with a
1063 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1064 series notebooks, it is necessary to say Y because of a BIOS bug.
1066 config APM_DO_ENABLE
1067 bool "Enable PM at boot time"
1068 depends on APM
1069 ---help---
1070 Enable APM features at boot time. From page 36 of the APM BIOS
1071 specification: "When disabled, the APM BIOS does not automatically
1072 power manage devices, enter the Standby State, enter the Suspend
1073 State, or take power saving steps in response to CPU Idle calls."
1074 This driver will make CPU Idle calls when Linux is idle (unless this
1075 feature is turned off -- see "Do CPU IDLE calls", below). This
1076 should always save battery power, but more complicated APM features
1077 will be dependent on your BIOS implementation. You may need to turn
1078 this option off if your computer hangs at boot time when using APM
1079 support, or if it beeps continuously instead of suspending. Turn
1080 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1081 T400CDT. This is off by default since most machines do fine without
1082 this feature.
1084 config APM_CPU_IDLE
1085 bool "Make CPU Idle calls when idle"
1086 depends on APM
1087 help
1088 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1089 On some machines, this can activate improved power savings, such as
1090 a slowed CPU clock rate, when the machine is idle. These idle calls
1091 are made after the idle loop has run for some length of time (e.g.,
1092 333 mS). On some machines, this will cause a hang at boot time or
1093 whenever the CPU becomes idle. (On machines with more than one CPU,
1094 this option does nothing.)
1096 config APM_DISPLAY_BLANK
1097 bool "Enable console blanking using APM"
1098 depends on APM
1099 help
1100 Enable console blanking using the APM. Some laptops can use this to
1101 turn off the LCD backlight when the screen blanker of the Linux
1102 virtual console blanks the screen. Note that this is only used by
1103 the virtual console screen blanker, and won't turn off the backlight
1104 when using the X Window system. This also doesn't have anything to
1105 do with your VESA-compliant power-saving monitor. Further, this
1106 option doesn't work for all laptops -- it might not turn off your
1107 backlight at all, or it might print a lot of errors to the console,
1108 especially if you are using gpm.
1110 config APM_RTC_IS_GMT
1111 bool "RTC stores time in GMT"
1112 depends on APM
1113 help
1114 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1115 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1116 stores localtime.
1118 It is in fact recommended to store GMT in your RTC, because then you
1119 don't have to worry about daylight savings time changes. The only
1120 reason not to use GMT in your RTC is if you also run a broken OS
1121 that doesn't understand GMT.
1123 config APM_ALLOW_INTS
1124 bool "Allow interrupts during APM BIOS calls"
1125 depends on APM
1126 help
1127 Normally we disable external interrupts while we are making calls to
1128 the APM BIOS as a measure to lessen the effects of a badly behaving
1129 BIOS implementation. The BIOS should reenable interrupts if it
1130 needs to. Unfortunately, some BIOSes do not -- especially those in
1131 many of the newer IBM Thinkpads. If you experience hangs when you
1132 suspend, try setting this to Y. Otherwise, say N.
1134 config APM_REAL_MODE_POWER_OFF
1135 bool "Use real mode APM BIOS call to power off"
1136 depends on APM
1137 help
1138 Use real mode APM BIOS calls to switch off the computer. This is
1139 a work-around for a number of buggy BIOSes. Switch this option on if
1140 your computer crashes instead of powering off properly.
1142 endmenu
1144 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1146 endmenu
1148 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1150 config PCI
1151 bool "PCI support" if !X86_VISWS
1152 depends on !X86_VOYAGER
1153 default y if X86_VISWS
1154 help
1155 Find out whether you have a PCI motherboard. PCI is the name of a
1156 bus system, i.e. the way the CPU talks to the other stuff inside
1157 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1158 VESA. If you have PCI, say Y, otherwise N.
1160 The PCI-HOWTO, available from
1161 <http://www.tldp.org/docs.html#howto>, contains valuable
1162 information about which PCI hardware does work under Linux and which
1163 doesn't.
1165 choice
1166 prompt "PCI access mode"
1167 depends on PCI && !X86_VISWS
1168 default PCI_GOANY
1169 ---help---
1170 On PCI systems, the BIOS can be used to detect the PCI devices and
1171 determine their configuration. However, some old PCI motherboards
1172 have BIOS bugs and may crash if this is done. Also, some embedded
1173 PCI-based systems don't have any BIOS at all. Linux can also try to
1174 detect the PCI hardware directly without using the BIOS.
1176 With this option, you can specify how Linux should detect the
1177 PCI devices. If you choose "BIOS", the BIOS will be used,
1178 if you choose "Direct", the BIOS won't be used, and if you
1179 choose "MMConfig", then PCI Express MMCONFIG will be used.
1180 If you choose "Any", the kernel will try MMCONFIG, then the
1181 direct access method and falls back to the BIOS if that doesn't
1182 work. If unsure, go with the default, which is "Any".
1184 config PCI_GOBIOS
1185 bool "BIOS"
1187 config PCI_GOMMCONFIG
1188 bool "MMConfig"
1190 config PCI_GODIRECT
1191 bool "Direct"
1193 config PCI_GOANY
1194 bool "Any"
1196 endchoice
1198 config PCI_BIOS
1199 bool
1200 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1201 default y
1203 config PCI_DIRECT
1204 bool
1205 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1206 default y
1208 config PCI_MMCONFIG
1209 bool
1210 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1211 select ACPI_BOOT
1212 default y
1214 source "drivers/pci/pcie/Kconfig"
1216 source "drivers/pci/Kconfig"
1218 config ISA_DMA_API
1219 bool
1220 default y
1222 config ISA
1223 bool "ISA support"
1224 depends on !(X86_VOYAGER || X86_VISWS)
1225 help
1226 Find out whether you have ISA slots on your motherboard. ISA is the
1227 name of a bus system, i.e. the way the CPU talks to the other stuff
1228 inside your box. Other bus systems are PCI, EISA, MicroChannel
1229 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1230 newer boards don't support it. If you have ISA, say Y, otherwise N.
1232 config EISA
1233 bool "EISA support"
1234 depends on ISA
1235 ---help---
1236 The Extended Industry Standard Architecture (EISA) bus was
1237 developed as an open alternative to the IBM MicroChannel bus.
1239 The EISA bus provided some of the features of the IBM MicroChannel
1240 bus while maintaining backward compatibility with cards made for
1241 the older ISA bus. The EISA bus saw limited use between 1988 and
1242 1995 when it was made obsolete by the PCI bus.
1244 Say Y here if you are building a kernel for an EISA-based machine.
1246 Otherwise, say N.
1248 source "drivers/eisa/Kconfig"
1250 config MCA
1251 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1252 default y if X86_VOYAGER
1253 help
1254 MicroChannel Architecture is found in some IBM PS/2 machines and
1255 laptops. It is a bus system similar to PCI or ISA. See
1256 <file:Documentation/mca.txt> (and especially the web page given
1257 there) before attempting to build an MCA bus kernel.
1259 source "drivers/mca/Kconfig"
1261 config SCx200
1262 tristate "NatSemi SCx200 support"
1263 depends on !X86_VOYAGER
1264 help
1265 This provides basic support for the National Semiconductor SCx200
1266 processor. Right now this is just a driver for the GPIO pins.
1268 If you don't know what to do here, say N.
1270 This support is also available as a module. If compiled as a
1271 module, it will be called scx200.
1273 config HOTPLUG_CPU
1274 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
1275 depends on SMP && HOTPLUG && EXPERIMENTAL
1276 ---help---
1277 Say Y here to experiment with turning CPUs off and on. CPUs
1278 can be controlled through /sys/devices/system/cpu.
1280 Say N.
1282 source "drivers/pcmcia/Kconfig"
1284 source "drivers/pci/hotplug/Kconfig"
1286 endmenu
1288 menu "Executable file formats"
1290 source "fs/Kconfig.binfmt"
1292 endmenu
1294 source "net/Kconfig"
1296 source "drivers/Kconfig"
1298 source "fs/Kconfig"
1300 source "arch/i386/oprofile/Kconfig"
1302 source "arch/i386/Kconfig.debug"
1304 source "security/Kconfig"
1306 source "crypto/Kconfig"
1308 source "lib/Kconfig"
1310 #
1311 # Use the generic interrupt handling code in kernel/irq/:
1312 #
1313 config GENERIC_HARDIRQS
1314 bool
1315 default y
1317 config GENERIC_IRQ_PROBE
1318 bool
1319 default y
1321 config X86_SMP
1322 bool
1323 depends on SMP && !X86_VOYAGER
1324 default y
1326 config X86_HT
1327 bool
1328 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1329 default y
1331 config X86_BIOS_REBOOT
1332 bool
1333 depends on !(X86_VISWS || X86_VOYAGER)
1334 default y
1336 config X86_TRAMPOLINE
1337 bool
1338 depends on X86_SMP || (X86_VOYAGER && SMP)
1339 default y
1341 config PC
1342 bool
1343 depends on X86 && !EMBEDDED
1344 default y