2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
6 mainmenu "Linux Kernel Configuration"
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.
28 config GENERIC_ISA_DMA
38 menu "Processor type and features"
41 prompt "Subarchitecture Type"
47 Choose this option if your computer is a standard PC or compatible.
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.
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.
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.
70 bool "NUMAQ (IBM/Sequent)"
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>.
80 bool "Summit/EXA (IBM x440)"
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.
89 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
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.
98 bool "SGI 320/540 (Visual Workstation)"
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)"
112 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
113 It is intended for a generic binary kernel.
116 bool "Support for Unisys ES7000 IA32 series"
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
129 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
131 config X86_SUMMIT_NUMA
134 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
136 config X86_CYCLONE_TIMER
139 depends on X86_SUMMIT || X86_GENERICARCH
141 config ES7000_CLUSTERED_APIC
144 depends on SMP && X86_ES7000 && MPENTIUMIII
149 prompt "Processor family"
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
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".
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
200 bool "586/K5/5x86/6x86/6x86MX"
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.
207 bool "Pentium-Classic"
209 Select this for a Pentium Classic processor with the RDTSC (Read
210 Time Stamp Counter) instruction for benchmarking.
215 Select this for a Pentium with the MMX graphics/multimedia
216 extended instructions.
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.
226 bool "Pentium-II/Celeron(pre-Coppermine)"
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
235 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
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
245 Select this for Intel Pentium M (not Pentium-4 M)
249 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
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.
258 bool "K6/K6-II/K6-III"
260 Select this for an AMD K6-family processor. Enables use of
261 some extended instructions, and passes appropriate optimization
265 bool "Athlon/Duron/K7"
267 Select this for an AMD Athlon K7-family processor. Enables use of
268 some extended instructions, and passes appropriate optimization
272 bool "Opteron/Athlon64/Hammer/K8"
274 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
275 use of some extended instructions, and passes appropriate optimization
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).
288 Select this for a Transmeta Efficeon processor.
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.
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.
305 bool "Winchip-2A/Winchip-3"
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
316 Select this for a Geode GX1 (Cyrix MediaGX) chip.
319 bool "CyrixIII/VIA-C3"
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
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.
330 bool "VIA C3-2 (Nehemiah)"
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.
339 bool "Generic x86 support"
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.
352 # Define implied options from the CPU selection here
364 config X86_L1_CACHE_SHIFT
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
376 config RWSEM_XCHGADD_ALGORITHM
381 config GENERIC_CALIBRATE_DELAY
385 config X86_PPRO_FENCE
387 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1
392 depends on M586MMX || M586TSC || M586 || M486 || M386
395 config X86_WP_WORKS_OK
415 config X86_ALIGNMENT_16
417 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
422 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
425 config X86_INTEL_USERCOPY
427 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
430 config X86_USE_PPRO_CHECKSUM
432 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
437 depends on MCYRIXIII || MK7
442 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
446 bool "HPET Timer Support"
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
458 depends on HPET_TIMER && RTC=y
462 bool "Symmetric multi-processing support"
464 This enables support for systems with more than one CPU. If you have
465 a system with only one CPU, like most personal computers, say N. If
466 you have a system with more than one CPU, say Y.
468 If you say N here, the kernel will run on single and multiprocessor
469 machines, but will use only one CPU of a multiprocessor machine. If
470 you say Y here, the kernel will run on many, but not all,
471 singleprocessor machines. On a singleprocessor machine, the kernel
472 will run faster if you say N here.
474 Note that if you say Y here and choose architecture "586" or
475 "Pentium" under "Processor family", the kernel will not work on 486
476 architectures. Similarly, multiprocessor kernels for the "PPro"
477 architecture may not work on all Pentium based boards.
479 People using multiprocessor machines who say Y here should also say
480 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
481 Management" code will be disabled if you say Y here.
483 See also the <file:Documentation/smp.txt>,
484 <file:Documentation/i386/IO-APIC.txt>,
485 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
486 <http://www.tldp.org/docs.html#howto>.
488 If you don't know what to do here, say N.
491 int "Maximum number of CPUs (2-255)"
494 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
497 This allows you to specify the maximum number of CPUs which this
498 kernel will support. The maximum supported value is 255 and the
499 minimum value which makes sense is 2.
501 This is purely to save memory - each supported CPU adds
502 approximately eight kilobytes to the kernel image.
505 bool "SMT (Hyperthreading) scheduler support"
509 SMT scheduler support improves the CPU scheduler's decision making
510 when dealing with Intel Pentium 4 chips with HyperThreading at a
511 cost of slightly increased overhead in some places. If unsure say
514 source "kernel/Kconfig.preempt"
517 bool "Local APIC support on uniprocessors"
518 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
520 A local APIC (Advanced Programmable Interrupt Controller) is an
521 integrated interrupt controller in the CPU. If you have a single-CPU
522 system which has a processor with a local APIC, you can say Y here to
523 enable and use it. If you say Y here even though your machine doesn't
524 have a local APIC, then the kernel will still run with no slowdown at
525 all. The local APIC supports CPU-generated self-interrupts (timer,
526 performance counters), and the NMI watchdog which detects hard
530 bool "IO-APIC support on uniprocessors"
531 depends on X86_UP_APIC
533 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
534 SMP-capable replacement for PC-style interrupt controllers. Most
535 SMP systems and many recent uniprocessor systems have one.
537 If you have a single-CPU system with an IO-APIC, you can say Y here
538 to use it. If you say Y here even though your machine doesn't have
539 an IO-APIC, then the kernel will still run with no slowdown at all.
541 config X86_LOCAL_APIC
543 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
548 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
551 config X86_VISWS_APIC
558 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
562 bool "Machine Check Exception"
563 depends on !X86_VOYAGER
565 Machine Check Exception support allows the processor to notify the
566 kernel if it detects a problem (e.g. overheating, component failure).
567 The action the kernel takes depends on the severity of the problem,
568 ranging from a warning message on the console, to halting the machine.
569 Your processor must be a Pentium or newer to support this - check the
570 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
571 have a design flaw which leads to false MCE events - hence MCE is
572 disabled on all P5 processors, unless explicitly enabled with "mce"
573 as a boot argument. Similarly, if MCE is built in and creates a
574 problem on some new non-standard machine, you can boot with "nomce"
575 to disable it. MCE support simply ignores non-MCE processors like
576 the 386 and 486, so nearly everyone can say Y here.
578 config X86_MCE_NONFATAL
579 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
582 Enabling this feature starts a timer that triggers every 5 seconds which
583 will look at the machine check registers to see if anything happened.
584 Non-fatal problems automatically get corrected (but still logged).
585 Disable this if you don't want to see these messages.
586 Seeing the messages this option prints out may be indicative of dying hardware,
587 or out-of-spec (ie, overclocked) hardware.
588 This option only does something on certain CPUs.
589 (AMD Athlon/Duron and Intel Pentium 4)
591 config X86_MCE_P4THERMAL
592 bool "check for P4 thermal throttling interrupt."
593 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
595 Enabling this feature will cause a message to be printed when the P4
596 enters thermal throttling.
599 tristate "Toshiba Laptop support"
601 This adds a driver to safely access the System Management Mode of
602 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
603 not work on models with a Phoenix BIOS. The System Management Mode
604 is used to set the BIOS and power saving options on Toshiba portables.
606 For information on utilities to make use of this driver see the
607 Toshiba Linux utilities web site at:
608 <http://www.buzzard.org.uk/toshiba/>.
610 Say Y if you intend to run this kernel on a Toshiba portable.
614 tristate "Dell laptop support"
616 This adds a driver to safely access the System Management Mode
617 of the CPU on the Dell Inspiron 8000. The System Management Mode
618 is used to read cpu temperature and cooling fan status and to
619 control the fans on the I8K portables.
621 This driver has been tested only on the Inspiron 8000 but it may
622 also work with other Dell laptops. You can force loading on other
623 models by passing the parameter `force=1' to the module. Use at
626 For information on utilities to make use of this driver see the
627 I8K Linux utilities web site at:
628 <http://people.debian.org/~dz/i8k/>
630 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
633 config X86_REBOOTFIXUPS
634 bool "Enable X86 board specific fixups for reboot"
638 This enables chipset and/or board specific fixups to be done
639 in order to get reboot to work correctly. This is only needed on
640 some combinations of hardware and BIOS. The symptom, for which
641 this config is intended, is when reboot ends with a stalled/hung
644 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
647 Say Y if you want to enable the fixup. Currently, it's safe to
648 enable this option even if you don't need it.
652 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
654 If you say Y here and also to "/dev file system support" in the
655 'File systems' section, you will be able to update the microcode on
656 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
657 Pentium III, Pentium 4, Xeon etc. You will obviously need the
658 actual microcode binary data itself which is not shipped with the
661 For latest news and information on obtaining all the required
662 ingredients for this driver, check:
663 <http://www.urbanmyth.org/microcode/>.
665 To compile this driver as a module, choose M here: the
666 module will be called microcode.
669 tristate "/dev/cpu/*/msr - Model-specific register support"
671 This device gives privileged processes access to the x86
672 Model-Specific Registers (MSRs). It is a character device with
673 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
674 MSR accesses are directed to a specific CPU on multi-processor
678 tristate "/dev/cpu/*/cpuid - CPU information support"
680 This device gives processes access to the x86 CPUID instruction to
681 be executed on a specific processor. It is a character device
682 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
685 source "drivers/firmware/Kconfig"
688 prompt "High Memory Support"
694 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
695 However, the address space of 32-bit x86 processors is only 4
696 Gigabytes large. That means that, if you have a large amount of
697 physical memory, not all of it can be "permanently mapped" by the
698 kernel. The physical memory that's not permanently mapped is called
701 If you are compiling a kernel which will never run on a machine with
702 more than 1 Gigabyte total physical RAM, answer "off" here (default
703 choice and suitable for most users). This will result in a "3GB/1GB"
704 split: 3GB are mapped so that each process sees a 3GB virtual memory
705 space and the remaining part of the 4GB virtual memory space is used
706 by the kernel to permanently map as much physical memory as
709 If the machine has between 1 and 4 Gigabytes physical RAM, then
712 If more than 4 Gigabytes is used then answer "64GB" here. This
713 selection turns Intel PAE (Physical Address Extension) mode on.
714 PAE implements 3-level paging on IA32 processors. PAE is fully
715 supported by Linux, PAE mode is implemented on all recent Intel
716 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
717 then the kernel will not boot on CPUs that don't support PAE!
719 The actual amount of total physical memory will either be
720 auto detected or can be forced by using a kernel command line option
721 such as "mem=256M". (Try "man bootparam" or see the documentation of
722 your boot loader (lilo or loadlin) about how to pass options to the
723 kernel at boot time.)
725 If unsure, say "off".
730 Select this if you have a 32-bit processor and between 1 and 4
731 gigabytes of physical RAM.
736 Select this if you have a 32-bit processor and more than 4
737 gigabytes of physical RAM.
743 depends on HIGHMEM64G || HIGHMEM4G
748 depends on HIGHMEM64G
751 # Common NUMA Features
753 bool "Numa Memory Allocation and Scheduler Support"
754 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
756 default y if (X86_NUMAQ || X86_SUMMIT)
757 select SPARSEMEM_STATIC
759 # Need comments to help the hapless user trying to turn on NUMA support
760 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
761 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
763 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
764 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
766 config HAVE_ARCH_BOOTMEM_NODE
771 config ARCH_HAVE_MEMORY_PRESENT
773 depends on DISCONTIGMEM
776 config NEED_NODE_MEMMAP_SIZE
778 depends on DISCONTIGMEM || SPARSEMEM
781 config HAVE_ARCH_ALLOC_REMAP
786 config ARCH_DISCONTIGMEM_ENABLE
790 config ARCH_DISCONTIGMEM_DEFAULT
794 config ARCH_SPARSEMEM_ENABLE
798 config ARCH_SELECT_MEMORY_MODEL
800 depends on ARCH_SPARSEMEM_ENABLE
804 config HAVE_ARCH_EARLY_PFN_TO_NID
810 bool "Allocate 3rd-level pagetables from highmem"
811 depends on HIGHMEM4G || HIGHMEM64G
813 The VM uses one page table entry for each page of physical memory.
814 For systems with a lot of RAM, this can be wasteful of precious
815 low memory. Setting this option will put user-space page table
816 entries in high memory.
818 config MATH_EMULATION
819 bool "Math emulation"
821 Linux can emulate a math coprocessor (used for floating point
822 operations) if you don't have one. 486DX and Pentium processors have
823 a math coprocessor built in, 486SX and 386 do not, unless you added
824 a 487DX or 387, respectively. (The messages during boot time can
825 give you some hints here ["man dmesg"].) Everyone needs either a
826 coprocessor or this emulation.
828 If you don't have a math coprocessor, you need to say Y here; if you
829 say Y here even though you have a coprocessor, the coprocessor will
830 be used nevertheless. (This behavior can be changed with the kernel
831 command line option "no387", which comes handy if your coprocessor
832 is broken. Try "man bootparam" or see the documentation of your boot
833 loader (lilo or loadlin) about how to pass options to the kernel at
834 boot time.) This means that it is a good idea to say Y here if you
835 intend to use this kernel on different machines.
837 More information about the internals of the Linux math coprocessor
838 emulation can be found in <file:arch/i386/math-emu/README>.
840 If you are not sure, say Y; apart from resulting in a 66 KB bigger
841 kernel, it won't hurt.
844 bool "MTRR (Memory Type Range Register) support"
846 On Intel P6 family processors (Pentium Pro, Pentium II and later)
847 the Memory Type Range Registers (MTRRs) may be used to control
848 processor access to memory ranges. This is most useful if you have
849 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
850 allows bus write transfers to be combined into a larger transfer
851 before bursting over the PCI/AGP bus. This can increase performance
852 of image write operations 2.5 times or more. Saying Y here creates a
853 /proc/mtrr file which may be used to manipulate your processor's
854 MTRRs. Typically the X server should use this.
856 This code has a reasonably generic interface so that similar
857 control registers on other processors can be easily supported
860 The Cyrix 6x86, 6x86MX and M II processors have Address Range
861 Registers (ARRs) which provide a similar functionality to MTRRs. For
862 these, the ARRs are used to emulate the MTRRs.
863 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
864 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
865 write-combining. All of these processors are supported by this code
866 and it makes sense to say Y here if you have one of them.
868 Saying Y here also fixes a problem with buggy SMP BIOSes which only
869 set the MTRRs for the boot CPU and not for the secondary CPUs. This
870 can lead to all sorts of problems, so it's good to say Y here.
872 You can safely say Y even if your machine doesn't have MTRRs, you'll
873 just add about 9 KB to your kernel.
875 See <file:Documentation/mtrr.txt> for more information.
878 bool "Boot from EFI support (EXPERIMENTAL)"
882 This enables the the kernel to boot on EFI platforms using
883 system configuration information passed to it from the firmware.
884 This also enables the kernel to use any EFI runtime services that are
885 available (such as the EFI variable services).
887 This option is only useful on systems that have EFI firmware
888 and will result in a kernel image that is ~8k larger. In addition,
889 you must use the latest ELILO loader available at
890 <http://elilo.sourceforge.net> in order to take advantage of
891 kernel initialization using EFI information (neither GRUB nor LILO know
892 anything about EFI). However, even with this option, the resultant
893 kernel should continue to boot on existing non-EFI platforms.
896 bool "Enable kernel irq balancing"
897 depends on SMP && X86_IO_APIC
900 The default yes will allow the kernel to do irq load balancing.
901 Saying no will keep the kernel from doing irq load balancing.
905 depends on (SMP || PREEMPT) && X86_CMPXCHG
908 # turning this on wastes a bunch of space.
909 # Summit needs it only when NUMA is on
912 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
916 bool "Use register arguments (EXPERIMENTAL)"
917 depends on EXPERIMENTAL
920 Compile the kernel with -mregparm=3. This uses a different ABI
921 and passes the first three arguments of a function call in registers.
922 This will probably break binary only modules.
924 This feature is only enabled for gcc-3.0 and later - earlier compilers
925 generate incorrect output with certain kernel constructs when
929 bool "Enable seccomp to safely compute untrusted bytecode"
933 This kernel feature is useful for number crunching applications
934 that may need to compute untrusted bytecode during their
935 execution. By using pipes or other transports made available to
936 the process as file descriptors supporting the read/write
937 syscalls, it's possible to isolate those applications in
938 their own address space using seccomp. Once seccomp is
939 enabled via /proc/<pid>/seccomp, it cannot be disabled
940 and the task is only allowed to execute a few safe syscalls
941 defined by each seccomp mode.
943 If unsure, say Y. Only embedded should say N here.
945 source kernel/Kconfig.hz
947 config PHYSICAL_START
948 hex "Physical address where the kernel is loaded" if EMBEDDED
951 This gives the physical address where the kernel is loaded.
952 Primarily used in the case of kexec on panic where the
953 fail safe kernel needs to run at a different address than
956 Don't change this unless you know what you are doing.
959 bool "kexec system call (EXPERIMENTAL)"
960 depends on EXPERIMENTAL
962 kexec is a system call that implements the ability to shutdown your
963 current kernel, and to start another kernel. It is like a reboot
964 but it is indepedent of the system firmware. And like a reboot
965 you can start any kernel with it, not just Linux.
967 The name comes from the similiarity to the exec system call.
969 It is an ongoing process to be certain the hardware in a machine
970 is properly shutdown, so do not be surprised if this code does not
971 initially work for you. It may help to enable device hotplugging
972 support. As of this writing the exact hardware interface is
973 strongly in flux, so no good recommendation can be made.
976 bool "kernel crash dumps (EXPERIMENTAL)"
978 depends on EXPERIMENTAL
981 Generate crash dump after being started by kexec.
985 menu "Power management options (ACPI, APM)"
986 depends on !X86_VOYAGER
988 source kernel/power/Kconfig
990 source "drivers/acpi/Kconfig"
992 menu "APM (Advanced Power Management) BIOS Support"
993 depends on PM && !X86_VISWS
996 tristate "APM (Advanced Power Management) BIOS support"
999 APM is a BIOS specification for saving power using several different
1000 techniques. This is mostly useful for battery powered laptops with
1001 APM compliant BIOSes. If you say Y here, the system time will be
1002 reset after a RESUME operation, the /proc/apm device will provide
1003 battery status information, and user-space programs will receive
1004 notification of APM "events" (e.g. battery status change).
1006 If you select "Y" here, you can disable actual use of the APM
1007 BIOS by passing the "apm=off" option to the kernel at boot time.
1009 Note that the APM support is almost completely disabled for
1010 machines with more than one CPU.
1012 In order to use APM, you will need supporting software. For location
1013 and more information, read <file:Documentation/pm.txt> and the
1014 Battery Powered Linux mini-HOWTO, available from
1015 <http://www.tldp.org/docs.html#howto>.
1017 This driver does not spin down disk drives (see the hdparm(8)
1018 manpage ("man 8 hdparm") for that), and it doesn't turn off
1019 VESA-compliant "green" monitors.
1021 This driver does not support the TI 4000M TravelMate and the ACER
1022 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1023 desktop machines also don't have compliant BIOSes, and this driver
1024 may cause those machines to panic during the boot phase.
1026 Generally, if you don't have a battery in your machine, there isn't
1027 much point in using this driver and you should say N. If you get
1028 random kernel OOPSes or reboots that don't seem to be related to
1029 anything, try disabling/enabling this option (or disabling/enabling
1032 Some other things you should try when experiencing seemingly random,
1035 1) make sure that you have enough swap space and that it is
1037 2) pass the "no-hlt" option to the kernel
1038 3) switch on floating point emulation in the kernel and pass
1039 the "no387" option to the kernel
1040 4) pass the "floppy=nodma" option to the kernel
1041 5) pass the "mem=4M" option to the kernel (thereby disabling
1042 all but the first 4 MB of RAM)
1043 6) make sure that the CPU is not over clocked.
1044 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1045 8) disable the cache from your BIOS settings
1046 9) install a fan for the video card or exchange video RAM
1047 10) install a better fan for the CPU
1048 11) exchange RAM chips
1049 12) exchange the motherboard.
1051 To compile this driver as a module, choose M here: the
1052 module will be called apm.
1054 config APM_IGNORE_USER_SUSPEND
1055 bool "Ignore USER SUSPEND"
1058 This option will ignore USER SUSPEND requests. On machines with a
1059 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1060 series notebooks, it is necessary to say Y because of a BIOS bug.
1062 config APM_DO_ENABLE
1063 bool "Enable PM at boot time"
1066 Enable APM features at boot time. From page 36 of the APM BIOS
1067 specification: "When disabled, the APM BIOS does not automatically
1068 power manage devices, enter the Standby State, enter the Suspend
1069 State, or take power saving steps in response to CPU Idle calls."
1070 This driver will make CPU Idle calls when Linux is idle (unless this
1071 feature is turned off -- see "Do CPU IDLE calls", below). This
1072 should always save battery power, but more complicated APM features
1073 will be dependent on your BIOS implementation. You may need to turn
1074 this option off if your computer hangs at boot time when using APM
1075 support, or if it beeps continuously instead of suspending. Turn
1076 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1077 T400CDT. This is off by default since most machines do fine without
1081 bool "Make CPU Idle calls when idle"
1084 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1085 On some machines, this can activate improved power savings, such as
1086 a slowed CPU clock rate, when the machine is idle. These idle calls
1087 are made after the idle loop has run for some length of time (e.g.,
1088 333 mS). On some machines, this will cause a hang at boot time or
1089 whenever the CPU becomes idle. (On machines with more than one CPU,
1090 this option does nothing.)
1092 config APM_DISPLAY_BLANK
1093 bool "Enable console blanking using APM"
1096 Enable console blanking using the APM. Some laptops can use this to
1097 turn off the LCD backlight when the screen blanker of the Linux
1098 virtual console blanks the screen. Note that this is only used by
1099 the virtual console screen blanker, and won't turn off the backlight
1100 when using the X Window system. This also doesn't have anything to
1101 do with your VESA-compliant power-saving monitor. Further, this
1102 option doesn't work for all laptops -- it might not turn off your
1103 backlight at all, or it might print a lot of errors to the console,
1104 especially if you are using gpm.
1106 config APM_RTC_IS_GMT
1107 bool "RTC stores time in GMT"
1110 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1111 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1114 It is in fact recommended to store GMT in your RTC, because then you
1115 don't have to worry about daylight savings time changes. The only
1116 reason not to use GMT in your RTC is if you also run a broken OS
1117 that doesn't understand GMT.
1119 config APM_ALLOW_INTS
1120 bool "Allow interrupts during APM BIOS calls"
1123 Normally we disable external interrupts while we are making calls to
1124 the APM BIOS as a measure to lessen the effects of a badly behaving
1125 BIOS implementation. The BIOS should reenable interrupts if it
1126 needs to. Unfortunately, some BIOSes do not -- especially those in
1127 many of the newer IBM Thinkpads. If you experience hangs when you
1128 suspend, try setting this to Y. Otherwise, say N.
1130 config APM_REAL_MODE_POWER_OFF
1131 bool "Use real mode APM BIOS call to power off"
1134 Use real mode APM BIOS calls to switch off the computer. This is
1135 a work-around for a number of buggy BIOSes. Switch this option on if
1136 your computer crashes instead of powering off properly.
1140 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1144 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1147 bool "PCI support" if !X86_VISWS
1148 depends on !X86_VOYAGER
1149 default y if X86_VISWS
1151 Find out whether you have a PCI motherboard. PCI is the name of a
1152 bus system, i.e. the way the CPU talks to the other stuff inside
1153 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1154 VESA. If you have PCI, say Y, otherwise N.
1156 The PCI-HOWTO, available from
1157 <http://www.tldp.org/docs.html#howto>, contains valuable
1158 information about which PCI hardware does work under Linux and which
1162 prompt "PCI access mode"
1163 depends on PCI && !X86_VISWS
1166 On PCI systems, the BIOS can be used to detect the PCI devices and
1167 determine their configuration. However, some old PCI motherboards
1168 have BIOS bugs and may crash if this is done. Also, some embedded
1169 PCI-based systems don't have any BIOS at all. Linux can also try to
1170 detect the PCI hardware directly without using the BIOS.
1172 With this option, you can specify how Linux should detect the
1173 PCI devices. If you choose "BIOS", the BIOS will be used,
1174 if you choose "Direct", the BIOS won't be used, and if you
1175 choose "MMConfig", then PCI Express MMCONFIG will be used.
1176 If you choose "Any", the kernel will try MMCONFIG, then the
1177 direct access method and falls back to the BIOS if that doesn't
1178 work. If unsure, go with the default, which is "Any".
1183 config PCI_GOMMCONFIG
1196 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1201 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1206 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1210 source "drivers/pci/pcie/Kconfig"
1212 source "drivers/pci/Kconfig"
1220 depends on !(X86_VOYAGER || X86_VISWS)
1222 Find out whether you have ISA slots on your motherboard. ISA is the
1223 name of a bus system, i.e. the way the CPU talks to the other stuff
1224 inside your box. Other bus systems are PCI, EISA, MicroChannel
1225 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1226 newer boards don't support it. If you have ISA, say Y, otherwise N.
1232 The Extended Industry Standard Architecture (EISA) bus was
1233 developed as an open alternative to the IBM MicroChannel bus.
1235 The EISA bus provided some of the features of the IBM MicroChannel
1236 bus while maintaining backward compatibility with cards made for
1237 the older ISA bus. The EISA bus saw limited use between 1988 and
1238 1995 when it was made obsolete by the PCI bus.
1240 Say Y here if you are building a kernel for an EISA-based machine.
1244 source "drivers/eisa/Kconfig"
1247 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1248 default y if X86_VOYAGER
1250 MicroChannel Architecture is found in some IBM PS/2 machines and
1251 laptops. It is a bus system similar to PCI or ISA. See
1252 <file:Documentation/mca.txt> (and especially the web page given
1253 there) before attempting to build an MCA bus kernel.
1255 source "drivers/mca/Kconfig"
1258 tristate "NatSemi SCx200 support"
1259 depends on !X86_VOYAGER
1261 This provides basic support for the National Semiconductor SCx200
1262 processor. Right now this is just a driver for the GPIO pins.
1264 If you don't know what to do here, say N.
1266 This support is also available as a module. If compiled as a
1267 module, it will be called scx200.
1270 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
1271 depends on SMP && HOTPLUG && EXPERIMENTAL
1273 Say Y here to experiment with turning CPUs off and on. CPUs
1274 can be controlled through /sys/devices/system/cpu.
1278 source "drivers/pcmcia/Kconfig"
1280 source "drivers/pci/hotplug/Kconfig"
1284 menu "Executable file formats"
1286 source "fs/Kconfig.binfmt"
1290 source "net/Kconfig"
1292 source "drivers/Kconfig"
1296 source "arch/i386/oprofile/Kconfig"
1298 source "arch/i386/Kconfig.debug"
1300 source "security/Kconfig"
1302 source "crypto/Kconfig"
1304 source "lib/Kconfig"
1307 # Use the generic interrupt handling code in kernel/irq/:
1309 config GENERIC_HARDIRQS
1313 config GENERIC_IRQ_PROBE
1319 depends on SMP && !X86_VOYAGER
1324 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1327 config X86_BIOS_REBOOT
1329 depends on !(X86_VISWS || X86_VOYAGER)
1332 config X86_TRAMPOLINE
1334 depends on X86_SMP || (X86_VOYAGER && SMP)
1339 depends on X86 && !EMBEDDED