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.
17 config SEMAPHORE_SLEEPERS
36 config GENERIC_ISA_DMA
44 config ARCH_MAY_HAVE_PC_FDC
50 menu "Processor type and features"
53 prompt "Subarchitecture Type"
59 Choose this option if your computer is a standard PC or compatible.
64 Select this for an AMD Elan processor.
66 Do not use this option for K6/Athlon/Opteron processors!
68 If unsure, choose "PC-compatible" instead.
73 Voyager is an MCA-based 32-way capable SMP architecture proprietary
74 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
78 If you do not specifically know you have a Voyager based machine,
79 say N here, otherwise the kernel you build will not be bootable.
82 bool "NUMAQ (IBM/Sequent)"
85 This option is used for getting Linux to run on a (IBM/Sequent) NUMA
86 multiquad box. This changes the way that processors are bootstrapped,
87 and uses Clustered Logical APIC addressing mode instead of Flat Logical.
88 You will need a new lynxer.elf file to flash your firmware with - send
89 email to <Martin.Bligh@us.ibm.com>.
92 bool "Summit/EXA (IBM x440)"
95 This option is needed for IBM systems that use the Summit/EXA chipset.
96 In particular, it is needed for the x440.
98 If you don't have one of these computers, you should say N here.
101 bool "Support for other sub-arch SMP systems with more than 8 CPUs"
104 This option is needed for the systems that have more than 8 CPUs
105 and if the system is not of any sub-arch type above.
107 If you don't have such a system, you should say N here.
110 bool "SGI 320/540 (Visual Workstation)"
112 The SGI Visual Workstation series is an IA32-based workstation
113 based on SGI systems chips with some legacy PC hardware attached.
115 Say Y here to create a kernel to run on the SGI 320 or 540.
117 A kernel compiled for the Visual Workstation will not run on PCs
118 and vice versa. See <file:Documentation/sgi-visws.txt> for details.
120 config X86_GENERICARCH
121 bool "Generic architecture (Summit, bigsmp, ES7000, default)"
124 This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
125 It is intended for a generic binary kernel.
128 bool "Support for Unisys ES7000 IA32 series"
131 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
132 supposed to run on an IA32-based Unisys ES7000 system.
133 Only choose this option if you have such a system, otherwise you
141 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
143 config X86_SUMMIT_NUMA
146 depends on NUMA && (X86_SUMMIT || X86_GENERICARCH)
148 config X86_CYCLONE_TIMER
151 depends on X86_SUMMIT || X86_GENERICARCH
153 config ES7000_CLUSTERED_APIC
156 depends on SMP && X86_ES7000 && MPENTIUMIII
161 prompt "Processor family"
167 This is the processor type of your CPU. This information is used for
168 optimizing purposes. In order to compile a kernel that can run on
169 all x86 CPU types (albeit not optimally fast), you can specify
172 The kernel will not necessarily run on earlier architectures than
173 the one you have chosen, e.g. a Pentium optimized kernel will run on
174 a PPro, but not necessarily on a i486.
176 Here are the settings recommended for greatest speed:
177 - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
178 486DLC/DLC2, UMC 486SX-S and NexGen Nx586. Only "386" kernels
179 will run on a 386 class machine.
180 - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
181 SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
182 - "586" for generic Pentium CPUs lacking the TSC
183 (time stamp counter) register.
184 - "Pentium-Classic" for the Intel Pentium.
185 - "Pentium-MMX" for the Intel Pentium MMX.
186 - "Pentium-Pro" for the Intel Pentium Pro.
187 - "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
188 - "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
189 - "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
190 - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
191 - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
192 - "Crusoe" for the Transmeta Crusoe series.
193 - "Efficeon" for the Transmeta Efficeon series.
194 - "Winchip-C6" for original IDT Winchip.
195 - "Winchip-2" for IDT Winchip 2.
196 - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
197 - "GeodeGX1" for Geode GX1 (Cyrix MediaGX).
198 - "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
199 - "VIA C3-2 for VIA C3-2 "Nehemiah" (model 9 and above).
201 If you don't know what to do, choose "386".
206 Select this for a 486 series processor, either Intel or one of the
207 compatible processors from AMD, Cyrix, IBM, or Intel. Includes DX,
208 DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
212 bool "586/K5/5x86/6x86/6x86MX"
214 Select this for an 586 or 686 series processor such as the AMD K5,
215 the Cyrix 5x86, 6x86 and 6x86MX. This choice does not
216 assume the RDTSC (Read Time Stamp Counter) instruction.
219 bool "Pentium-Classic"
221 Select this for a Pentium Classic processor with the RDTSC (Read
222 Time Stamp Counter) instruction for benchmarking.
227 Select this for a Pentium with the MMX graphics/multimedia
228 extended instructions.
233 Select this for Intel Pentium Pro chips. This enables the use of
234 Pentium Pro extended instructions, and disables the init-time guard
235 against the f00f bug found in earlier Pentiums.
238 bool "Pentium-II/Celeron(pre-Coppermine)"
240 Select this for Intel chips based on the Pentium-II and
241 pre-Coppermine Celeron core. This option enables an unaligned
242 copy optimization, compiles the kernel with optimization flags
243 tailored for the chip, and applies any applicable Pentium Pro
247 bool "Pentium-III/Celeron(Coppermine)/Pentium-III Xeon"
249 Select this for Intel chips based on the Pentium-III and
250 Celeron-Coppermine core. This option enables use of some
251 extended prefetch instructions in addition to the Pentium II
257 Select this for Intel Pentium M (not Pentium-4 M)
261 bool "Pentium-4/Celeron(P4-based)/Pentium-4 M/Xeon"
263 Select this for Intel Pentium 4 chips. This includes the
264 Pentium 4, P4-based Celeron and Xeon, and Pentium-4 M
265 (not Pentium M) chips. This option enables compile flags
266 optimized for the chip, uses the correct cache shift, and
267 applies any applicable Pentium III optimizations.
270 bool "K6/K6-II/K6-III"
272 Select this for an AMD K6-family processor. Enables use of
273 some extended instructions, and passes appropriate optimization
277 bool "Athlon/Duron/K7"
279 Select this for an AMD Athlon K7-family processor. Enables use of
280 some extended instructions, and passes appropriate optimization
284 bool "Opteron/Athlon64/Hammer/K8"
286 Select this for an AMD Opteron or Athlon64 Hammer-family processor. Enables
287 use of some extended instructions, and passes appropriate optimization
293 Select this for a Transmeta Crusoe processor. Treats the processor
294 like a 586 with TSC, and sets some GCC optimization flags (like a
295 Pentium Pro with no alignment requirements).
300 Select this for a Transmeta Efficeon processor.
305 Select this for an IDT Winchip C6 chip. Linux and GCC
306 treat this chip as a 586TSC with some extended instructions
307 and alignment requirements.
312 Select this for an IDT Winchip-2. Linux and GCC
313 treat this chip as a 586TSC with some extended instructions
314 and alignment requirements.
317 bool "Winchip-2A/Winchip-3"
319 Select this for an IDT Winchip-2A or 3. Linux and GCC
320 treat this chip as a 586TSC with some extended instructions
321 and alignment reqirements. Also enable out of order memory
322 stores for this CPU, which can increase performance of some
328 Select this for a Geode GX1 (Cyrix MediaGX) chip.
331 bool "CyrixIII/VIA-C3"
333 Select this for a Cyrix III or C3 chip. Presently Linux and GCC
334 treat this chip as a generic 586. Whilst the CPU is 686 class,
335 it lacks the cmov extension which gcc assumes is present when
337 Note that Nehemiah (Model 9) and above will not boot with this
338 kernel due to them lacking the 3DNow! instructions used in earlier
339 incarnations of the CPU.
342 bool "VIA C3-2 (Nehemiah)"
344 Select this for a VIA C3 "Nehemiah". Selecting this enables usage
345 of SSE and tells gcc to treat the CPU as a 686.
346 Note, this kernel will not boot on older (pre model 9) C3s.
351 bool "Generic x86 support"
353 Instead of just including optimizations for the selected
354 x86 variant (e.g. PII, Crusoe or Athlon), include some more
355 generic optimizations as well. This will make the kernel
356 perform better on x86 CPUs other than that selected.
358 This is really intended for distributors who need more
359 generic optimizations.
364 # Define implied options from the CPU selection here
376 config X86_L1_CACHE_SHIFT
378 default "7" if MPENTIUM4 || X86_GENERIC
379 default "4" if X86_ELAN || M486 || M386
380 default "5" if MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODEGX1
381 default "6" if MK7 || MK8 || MPENTIUMM
383 config RWSEM_GENERIC_SPINLOCK
388 config RWSEM_XCHGADD_ALGORITHM
393 config GENERIC_CALIBRATE_DELAY
397 config X86_PPRO_FENCE
399 depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1
404 depends on M586MMX || M586TSC || M586 || M486 || M386
407 config X86_WP_WORKS_OK
429 depends on !M386 && !M486
432 config X86_ALIGNMENT_16
434 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
439 depends on MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || MK8 || MEFFICEON
442 config X86_INTEL_USERCOPY
444 depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON
447 config X86_USE_PPRO_CHECKSUM
449 depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MEFFICEON
454 depends on MCYRIXIII || MK7
459 depends on (MWINCHIP3D || MWINCHIP2 || MWINCHIPC6) && MTRR
463 bool "HPET Timer Support"
465 This enables the use of the HPET for the kernel's internal timer.
466 HPET is the next generation timer replacing legacy 8254s.
467 You can safely choose Y here. However, HPET will only be
468 activated if the platform and the BIOS support this feature.
469 Otherwise the 8254 will be used for timing services.
471 Choose N to continue using the legacy 8254 timer.
473 config HPET_EMULATE_RTC
475 depends on HPET_TIMER && RTC=y
479 bool "Symmetric multi-processing support"
481 This enables support for systems with more than one CPU. If you have
482 a system with only one CPU, like most personal computers, say N. If
483 you have a system with more than one CPU, say Y.
485 If you say N here, the kernel will run on single and multiprocessor
486 machines, but will use only one CPU of a multiprocessor machine. If
487 you say Y here, the kernel will run on many, but not all,
488 singleprocessor machines. On a singleprocessor machine, the kernel
489 will run faster if you say N here.
491 Note that if you say Y here and choose architecture "586" or
492 "Pentium" under "Processor family", the kernel will not work on 486
493 architectures. Similarly, multiprocessor kernels for the "PPro"
494 architecture may not work on all Pentium based boards.
496 People using multiprocessor machines who say Y here should also say
497 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
498 Management" code will be disabled if you say Y here.
500 See also the <file:Documentation/smp.txt>,
501 <file:Documentation/i386/IO-APIC.txt>,
502 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
503 <http://www.tldp.org/docs.html#howto>.
505 If you don't know what to do here, say N.
508 int "Maximum number of CPUs (2-255)"
511 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
514 This allows you to specify the maximum number of CPUs which this
515 kernel will support. The maximum supported value is 255 and the
516 minimum value which makes sense is 2.
518 This is purely to save memory - each supported CPU adds
519 approximately eight kilobytes to the kernel image.
522 bool "SMT (Hyperthreading) scheduler support"
526 SMT scheduler support improves the CPU scheduler's decision making
527 when dealing with Intel Pentium 4 chips with HyperThreading at a
528 cost of slightly increased overhead in some places. If unsure say
531 source "kernel/Kconfig.preempt"
534 bool "Local APIC support on uniprocessors"
535 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
537 A local APIC (Advanced Programmable Interrupt Controller) is an
538 integrated interrupt controller in the CPU. If you have a single-CPU
539 system which has a processor with a local APIC, you can say Y here to
540 enable and use it. If you say Y here even though your machine doesn't
541 have a local APIC, then the kernel will still run with no slowdown at
542 all. The local APIC supports CPU-generated self-interrupts (timer,
543 performance counters), and the NMI watchdog which detects hard
547 bool "IO-APIC support on uniprocessors"
548 depends on X86_UP_APIC
550 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
551 SMP-capable replacement for PC-style interrupt controllers. Most
552 SMP systems and many recent uniprocessor systems have one.
554 If you have a single-CPU system with an IO-APIC, you can say Y here
555 to use it. If you say Y here even though your machine doesn't have
556 an IO-APIC, then the kernel will still run with no slowdown at all.
558 config X86_LOCAL_APIC
560 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
565 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
568 config X86_VISWS_APIC
575 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
579 bool "Machine Check Exception"
580 depends on !X86_VOYAGER
582 Machine Check Exception support allows the processor to notify the
583 kernel if it detects a problem (e.g. overheating, component failure).
584 The action the kernel takes depends on the severity of the problem,
585 ranging from a warning message on the console, to halting the machine.
586 Your processor must be a Pentium or newer to support this - check the
587 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
588 have a design flaw which leads to false MCE events - hence MCE is
589 disabled on all P5 processors, unless explicitly enabled with "mce"
590 as a boot argument. Similarly, if MCE is built in and creates a
591 problem on some new non-standard machine, you can boot with "nomce"
592 to disable it. MCE support simply ignores non-MCE processors like
593 the 386 and 486, so nearly everyone can say Y here.
595 config X86_MCE_NONFATAL
596 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
599 Enabling this feature starts a timer that triggers every 5 seconds which
600 will look at the machine check registers to see if anything happened.
601 Non-fatal problems automatically get corrected (but still logged).
602 Disable this if you don't want to see these messages.
603 Seeing the messages this option prints out may be indicative of dying hardware,
604 or out-of-spec (ie, overclocked) hardware.
605 This option only does something on certain CPUs.
606 (AMD Athlon/Duron and Intel Pentium 4)
608 config X86_MCE_P4THERMAL
609 bool "check for P4 thermal throttling interrupt."
610 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
612 Enabling this feature will cause a message to be printed when the P4
613 enters thermal throttling.
616 tristate "Toshiba Laptop support"
618 This adds a driver to safely access the System Management Mode of
619 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
620 not work on models with a Phoenix BIOS. The System Management Mode
621 is used to set the BIOS and power saving options on Toshiba portables.
623 For information on utilities to make use of this driver see the
624 Toshiba Linux utilities web site at:
625 <http://www.buzzard.org.uk/toshiba/>.
627 Say Y if you intend to run this kernel on a Toshiba portable.
631 tristate "Dell laptop support"
633 This adds a driver to safely access the System Management Mode
634 of the CPU on the Dell Inspiron 8000. The System Management Mode
635 is used to read cpu temperature and cooling fan status and to
636 control the fans on the I8K portables.
638 This driver has been tested only on the Inspiron 8000 but it may
639 also work with other Dell laptops. You can force loading on other
640 models by passing the parameter `force=1' to the module. Use at
643 For information on utilities to make use of this driver see the
644 I8K Linux utilities web site at:
645 <http://people.debian.org/~dz/i8k/>
647 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
650 config X86_REBOOTFIXUPS
651 bool "Enable X86 board specific fixups for reboot"
655 This enables chipset and/or board specific fixups to be done
656 in order to get reboot to work correctly. This is only needed on
657 some combinations of hardware and BIOS. The symptom, for which
658 this config is intended, is when reboot ends with a stalled/hung
661 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
664 Say Y if you want to enable the fixup. Currently, it's safe to
665 enable this option even if you don't need it.
669 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
671 If you say Y here and also to "/dev file system support" in the
672 'File systems' section, you will be able to update the microcode on
673 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
674 Pentium III, Pentium 4, Xeon etc. You will obviously need the
675 actual microcode binary data itself which is not shipped with the
678 For latest news and information on obtaining all the required
679 ingredients for this driver, check:
680 <http://www.urbanmyth.org/microcode/>.
682 To compile this driver as a module, choose M here: the
683 module will be called microcode.
686 tristate "/dev/cpu/*/msr - Model-specific register support"
688 This device gives privileged processes access to the x86
689 Model-Specific Registers (MSRs). It is a character device with
690 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
691 MSR accesses are directed to a specific CPU on multi-processor
695 tristate "/dev/cpu/*/cpuid - CPU information support"
697 This device gives processes access to the x86 CPUID instruction to
698 be executed on a specific processor. It is a character device
699 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
702 source "drivers/firmware/Kconfig"
705 prompt "High Memory Support"
711 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
712 However, the address space of 32-bit x86 processors is only 4
713 Gigabytes large. That means that, if you have a large amount of
714 physical memory, not all of it can be "permanently mapped" by the
715 kernel. The physical memory that's not permanently mapped is called
718 If you are compiling a kernel which will never run on a machine with
719 more than 1 Gigabyte total physical RAM, answer "off" here (default
720 choice and suitable for most users). This will result in a "3GB/1GB"
721 split: 3GB are mapped so that each process sees a 3GB virtual memory
722 space and the remaining part of the 4GB virtual memory space is used
723 by the kernel to permanently map as much physical memory as
726 If the machine has between 1 and 4 Gigabytes physical RAM, then
729 If more than 4 Gigabytes is used then answer "64GB" here. This
730 selection turns Intel PAE (Physical Address Extension) mode on.
731 PAE implements 3-level paging on IA32 processors. PAE is fully
732 supported by Linux, PAE mode is implemented on all recent Intel
733 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
734 then the kernel will not boot on CPUs that don't support PAE!
736 The actual amount of total physical memory will either be
737 auto detected or can be forced by using a kernel command line option
738 such as "mem=256M". (Try "man bootparam" or see the documentation of
739 your boot loader (lilo or loadlin) about how to pass options to the
740 kernel at boot time.)
742 If unsure, say "off".
747 Select this if you have a 32-bit processor and between 1 and 4
748 gigabytes of physical RAM.
753 Select this if you have a 32-bit processor and more than 4
754 gigabytes of physical RAM.
760 depends on HIGHMEM64G || HIGHMEM4G
765 depends on HIGHMEM64G
768 # Common NUMA Features
770 bool "Numa Memory Allocation and Scheduler Support"
771 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
773 default y if (X86_NUMAQ || X86_SUMMIT)
774 select SPARSEMEM_STATIC
776 # Need comments to help the hapless user trying to turn on NUMA support
777 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
778 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
780 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
781 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
783 config HAVE_ARCH_BOOTMEM_NODE
788 config ARCH_HAVE_MEMORY_PRESENT
790 depends on DISCONTIGMEM
793 config NEED_NODE_MEMMAP_SIZE
795 depends on DISCONTIGMEM || SPARSEMEM
798 config HAVE_ARCH_ALLOC_REMAP
803 config ARCH_DISCONTIGMEM_ENABLE
807 config ARCH_DISCONTIGMEM_DEFAULT
811 config ARCH_SPARSEMEM_ENABLE
815 config ARCH_SELECT_MEMORY_MODEL
817 depends on ARCH_SPARSEMEM_ENABLE
821 config HAVE_ARCH_EARLY_PFN_TO_NID
827 bool "Allocate 3rd-level pagetables from highmem"
828 depends on HIGHMEM4G || HIGHMEM64G
830 The VM uses one page table entry for each page of physical memory.
831 For systems with a lot of RAM, this can be wasteful of precious
832 low memory. Setting this option will put user-space page table
833 entries in high memory.
835 config MATH_EMULATION
836 bool "Math emulation"
838 Linux can emulate a math coprocessor (used for floating point
839 operations) if you don't have one. 486DX and Pentium processors have
840 a math coprocessor built in, 486SX and 386 do not, unless you added
841 a 487DX or 387, respectively. (The messages during boot time can
842 give you some hints here ["man dmesg"].) Everyone needs either a
843 coprocessor or this emulation.
845 If you don't have a math coprocessor, you need to say Y here; if you
846 say Y here even though you have a coprocessor, the coprocessor will
847 be used nevertheless. (This behavior can be changed with the kernel
848 command line option "no387", which comes handy if your coprocessor
849 is broken. Try "man bootparam" or see the documentation of your boot
850 loader (lilo or loadlin) about how to pass options to the kernel at
851 boot time.) This means that it is a good idea to say Y here if you
852 intend to use this kernel on different machines.
854 More information about the internals of the Linux math coprocessor
855 emulation can be found in <file:arch/i386/math-emu/README>.
857 If you are not sure, say Y; apart from resulting in a 66 KB bigger
858 kernel, it won't hurt.
861 bool "MTRR (Memory Type Range Register) support"
863 On Intel P6 family processors (Pentium Pro, Pentium II and later)
864 the Memory Type Range Registers (MTRRs) may be used to control
865 processor access to memory ranges. This is most useful if you have
866 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
867 allows bus write transfers to be combined into a larger transfer
868 before bursting over the PCI/AGP bus. This can increase performance
869 of image write operations 2.5 times or more. Saying Y here creates a
870 /proc/mtrr file which may be used to manipulate your processor's
871 MTRRs. Typically the X server should use this.
873 This code has a reasonably generic interface so that similar
874 control registers on other processors can be easily supported
877 The Cyrix 6x86, 6x86MX and M II processors have Address Range
878 Registers (ARRs) which provide a similar functionality to MTRRs. For
879 these, the ARRs are used to emulate the MTRRs.
880 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
881 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
882 write-combining. All of these processors are supported by this code
883 and it makes sense to say Y here if you have one of them.
885 Saying Y here also fixes a problem with buggy SMP BIOSes which only
886 set the MTRRs for the boot CPU and not for the secondary CPUs. This
887 can lead to all sorts of problems, so it's good to say Y here.
889 You can safely say Y even if your machine doesn't have MTRRs, you'll
890 just add about 9 KB to your kernel.
892 See <file:Documentation/mtrr.txt> for more information.
895 bool "Boot from EFI support (EXPERIMENTAL)"
899 This enables the the kernel to boot on EFI platforms using
900 system configuration information passed to it from the firmware.
901 This also enables the kernel to use any EFI runtime services that are
902 available (such as the EFI variable services).
904 This option is only useful on systems that have EFI firmware
905 and will result in a kernel image that is ~8k larger. In addition,
906 you must use the latest ELILO loader available at
907 <http://elilo.sourceforge.net> in order to take advantage of
908 kernel initialization using EFI information (neither GRUB nor LILO know
909 anything about EFI). However, even with this option, the resultant
910 kernel should continue to boot on existing non-EFI platforms.
913 bool "Enable kernel irq balancing"
914 depends on SMP && X86_IO_APIC
917 The default yes will allow the kernel to do irq load balancing.
918 Saying no will keep the kernel from doing irq load balancing.
920 # turning this on wastes a bunch of space.
921 # Summit needs it only when NUMA is on
924 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
928 bool "Use register arguments (EXPERIMENTAL)"
929 depends on EXPERIMENTAL
932 Compile the kernel with -mregparm=3. This uses a different ABI
933 and passes the first three arguments of a function call in registers.
934 This will probably break binary only modules.
936 This feature is only enabled for gcc-3.0 and later - earlier compilers
937 generate incorrect output with certain kernel constructs when
941 bool "Enable seccomp to safely compute untrusted bytecode"
945 This kernel feature is useful for number crunching applications
946 that may need to compute untrusted bytecode during their
947 execution. By using pipes or other transports made available to
948 the process as file descriptors supporting the read/write
949 syscalls, it's possible to isolate those applications in
950 their own address space using seccomp. Once seccomp is
951 enabled via /proc/<pid>/seccomp, it cannot be disabled
952 and the task is only allowed to execute a few safe syscalls
953 defined by each seccomp mode.
955 If unsure, say Y. Only embedded should say N here.
957 source kernel/Kconfig.hz
959 config PHYSICAL_START
960 hex "Physical address where the kernel is loaded" if EMBEDDED
963 This gives the physical address where the kernel is loaded.
964 Primarily used in the case of kexec on panic where the
965 fail safe kernel needs to run at a different address than
968 Don't change this unless you know what you are doing.
971 bool "kexec system call (EXPERIMENTAL)"
972 depends on EXPERIMENTAL
974 kexec is a system call that implements the ability to shutdown your
975 current kernel, and to start another kernel. It is like a reboot
976 but it is indepedent of the system firmware. And like a reboot
977 you can start any kernel with it, not just Linux.
979 The name comes from the similiarity to the exec system call.
981 It is an ongoing process to be certain the hardware in a machine
982 is properly shutdown, so do not be surprised if this code does not
983 initially work for you. It may help to enable device hotplugging
984 support. As of this writing the exact hardware interface is
985 strongly in flux, so no good recommendation can be made.
988 bool "kernel crash dumps (EXPERIMENTAL)"
990 depends on EXPERIMENTAL
993 Generate crash dump after being started by kexec.
997 menu "Power management options (ACPI, APM)"
998 depends on !X86_VOYAGER
1000 source kernel/power/Kconfig
1002 source "drivers/acpi/Kconfig"
1004 menu "APM (Advanced Power Management) BIOS Support"
1005 depends on PM && !X86_VISWS
1008 tristate "APM (Advanced Power Management) BIOS support"
1011 APM is a BIOS specification for saving power using several different
1012 techniques. This is mostly useful for battery powered laptops with
1013 APM compliant BIOSes. If you say Y here, the system time will be
1014 reset after a RESUME operation, the /proc/apm device will provide
1015 battery status information, and user-space programs will receive
1016 notification of APM "events" (e.g. battery status change).
1018 If you select "Y" here, you can disable actual use of the APM
1019 BIOS by passing the "apm=off" option to the kernel at boot time.
1021 Note that the APM support is almost completely disabled for
1022 machines with more than one CPU.
1024 In order to use APM, you will need supporting software. For location
1025 and more information, read <file:Documentation/pm.txt> and the
1026 Battery Powered Linux mini-HOWTO, available from
1027 <http://www.tldp.org/docs.html#howto>.
1029 This driver does not spin down disk drives (see the hdparm(8)
1030 manpage ("man 8 hdparm") for that), and it doesn't turn off
1031 VESA-compliant "green" monitors.
1033 This driver does not support the TI 4000M TravelMate and the ACER
1034 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1035 desktop machines also don't have compliant BIOSes, and this driver
1036 may cause those machines to panic during the boot phase.
1038 Generally, if you don't have a battery in your machine, there isn't
1039 much point in using this driver and you should say N. If you get
1040 random kernel OOPSes or reboots that don't seem to be related to
1041 anything, try disabling/enabling this option (or disabling/enabling
1044 Some other things you should try when experiencing seemingly random,
1047 1) make sure that you have enough swap space and that it is
1049 2) pass the "no-hlt" option to the kernel
1050 3) switch on floating point emulation in the kernel and pass
1051 the "no387" option to the kernel
1052 4) pass the "floppy=nodma" option to the kernel
1053 5) pass the "mem=4M" option to the kernel (thereby disabling
1054 all but the first 4 MB of RAM)
1055 6) make sure that the CPU is not over clocked.
1056 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1057 8) disable the cache from your BIOS settings
1058 9) install a fan for the video card or exchange video RAM
1059 10) install a better fan for the CPU
1060 11) exchange RAM chips
1061 12) exchange the motherboard.
1063 To compile this driver as a module, choose M here: the
1064 module will be called apm.
1066 config APM_IGNORE_USER_SUSPEND
1067 bool "Ignore USER SUSPEND"
1070 This option will ignore USER SUSPEND requests. On machines with a
1071 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1072 series notebooks, it is necessary to say Y because of a BIOS bug.
1074 config APM_DO_ENABLE
1075 bool "Enable PM at boot time"
1078 Enable APM features at boot time. From page 36 of the APM BIOS
1079 specification: "When disabled, the APM BIOS does not automatically
1080 power manage devices, enter the Standby State, enter the Suspend
1081 State, or take power saving steps in response to CPU Idle calls."
1082 This driver will make CPU Idle calls when Linux is idle (unless this
1083 feature is turned off -- see "Do CPU IDLE calls", below). This
1084 should always save battery power, but more complicated APM features
1085 will be dependent on your BIOS implementation. You may need to turn
1086 this option off if your computer hangs at boot time when using APM
1087 support, or if it beeps continuously instead of suspending. Turn
1088 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1089 T400CDT. This is off by default since most machines do fine without
1093 bool "Make CPU Idle calls when idle"
1096 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1097 On some machines, this can activate improved power savings, such as
1098 a slowed CPU clock rate, when the machine is idle. These idle calls
1099 are made after the idle loop has run for some length of time (e.g.,
1100 333 mS). On some machines, this will cause a hang at boot time or
1101 whenever the CPU becomes idle. (On machines with more than one CPU,
1102 this option does nothing.)
1104 config APM_DISPLAY_BLANK
1105 bool "Enable console blanking using APM"
1108 Enable console blanking using the APM. Some laptops can use this to
1109 turn off the LCD backlight when the screen blanker of the Linux
1110 virtual console blanks the screen. Note that this is only used by
1111 the virtual console screen blanker, and won't turn off the backlight
1112 when using the X Window system. This also doesn't have anything to
1113 do with your VESA-compliant power-saving monitor. Further, this
1114 option doesn't work for all laptops -- it might not turn off your
1115 backlight at all, or it might print a lot of errors to the console,
1116 especially if you are using gpm.
1118 config APM_RTC_IS_GMT
1119 bool "RTC stores time in GMT"
1122 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1123 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1126 It is in fact recommended to store GMT in your RTC, because then you
1127 don't have to worry about daylight savings time changes. The only
1128 reason not to use GMT in your RTC is if you also run a broken OS
1129 that doesn't understand GMT.
1131 config APM_ALLOW_INTS
1132 bool "Allow interrupts during APM BIOS calls"
1135 Normally we disable external interrupts while we are making calls to
1136 the APM BIOS as a measure to lessen the effects of a badly behaving
1137 BIOS implementation. The BIOS should reenable interrupts if it
1138 needs to. Unfortunately, some BIOSes do not -- especially those in
1139 many of the newer IBM Thinkpads. If you experience hangs when you
1140 suspend, try setting this to Y. Otherwise, say N.
1142 config APM_REAL_MODE_POWER_OFF
1143 bool "Use real mode APM BIOS call to power off"
1146 Use real mode APM BIOS calls to switch off the computer. This is
1147 a work-around for a number of buggy BIOSes. Switch this option on if
1148 your computer crashes instead of powering off properly.
1152 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1156 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1159 bool "PCI support" if !X86_VISWS
1160 depends on !X86_VOYAGER
1161 default y if X86_VISWS
1163 Find out whether you have a PCI motherboard. PCI is the name of a
1164 bus system, i.e. the way the CPU talks to the other stuff inside
1165 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1166 VESA. If you have PCI, say Y, otherwise N.
1168 The PCI-HOWTO, available from
1169 <http://www.tldp.org/docs.html#howto>, contains valuable
1170 information about which PCI hardware does work under Linux and which
1174 prompt "PCI access mode"
1175 depends on PCI && !X86_VISWS
1178 On PCI systems, the BIOS can be used to detect the PCI devices and
1179 determine their configuration. However, some old PCI motherboards
1180 have BIOS bugs and may crash if this is done. Also, some embedded
1181 PCI-based systems don't have any BIOS at all. Linux can also try to
1182 detect the PCI hardware directly without using the BIOS.
1184 With this option, you can specify how Linux should detect the
1185 PCI devices. If you choose "BIOS", the BIOS will be used,
1186 if you choose "Direct", the BIOS won't be used, and if you
1187 choose "MMConfig", then PCI Express MMCONFIG will be used.
1188 If you choose "Any", the kernel will try MMCONFIG, then the
1189 direct access method and falls back to the BIOS if that doesn't
1190 work. If unsure, go with the default, which is "Any".
1195 config PCI_GOMMCONFIG
1208 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1213 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1218 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1221 source "drivers/pci/pcie/Kconfig"
1223 source "drivers/pci/Kconfig"
1231 depends on !(X86_VOYAGER || X86_VISWS)
1233 Find out whether you have ISA slots on your motherboard. ISA is the
1234 name of a bus system, i.e. the way the CPU talks to the other stuff
1235 inside your box. Other bus systems are PCI, EISA, MicroChannel
1236 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1237 newer boards don't support it. If you have ISA, say Y, otherwise N.
1243 The Extended Industry Standard Architecture (EISA) bus was
1244 developed as an open alternative to the IBM MicroChannel bus.
1246 The EISA bus provided some of the features of the IBM MicroChannel
1247 bus while maintaining backward compatibility with cards made for
1248 the older ISA bus. The EISA bus saw limited use between 1988 and
1249 1995 when it was made obsolete by the PCI bus.
1251 Say Y here if you are building a kernel for an EISA-based machine.
1255 source "drivers/eisa/Kconfig"
1258 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1259 default y if X86_VOYAGER
1261 MicroChannel Architecture is found in some IBM PS/2 machines and
1262 laptops. It is a bus system similar to PCI or ISA. See
1263 <file:Documentation/mca.txt> (and especially the web page given
1264 there) before attempting to build an MCA bus kernel.
1266 source "drivers/mca/Kconfig"
1269 tristate "NatSemi SCx200 support"
1270 depends on !X86_VOYAGER
1272 This provides basic support for the National Semiconductor SCx200
1273 processor. Right now this is just a driver for the GPIO pins.
1275 If you don't know what to do here, say N.
1277 This support is also available as a module. If compiled as a
1278 module, it will be called scx200.
1281 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
1282 depends on SMP && HOTPLUG && EXPERIMENTAL
1284 Say Y here to experiment with turning CPUs off and on. CPUs
1285 can be controlled through /sys/devices/system/cpu.
1289 source "drivers/pcmcia/Kconfig"
1291 source "drivers/pci/hotplug/Kconfig"
1295 menu "Executable file formats"
1297 source "fs/Kconfig.binfmt"
1301 source "net/Kconfig"
1303 source "drivers/Kconfig"
1307 source "arch/i386/oprofile/Kconfig"
1309 source "arch/i386/Kconfig.debug"
1311 source "security/Kconfig"
1313 source "crypto/Kconfig"
1315 source "lib/Kconfig"
1318 # Use the generic interrupt handling code in kernel/irq/:
1320 config GENERIC_HARDIRQS
1324 config GENERIC_IRQ_PROBE
1328 config GENERIC_PENDING_IRQ
1330 depends on GENERIC_HARDIRQS && SMP
1335 depends on SMP && !X86_VOYAGER
1340 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1343 config X86_BIOS_REBOOT
1345 depends on !(X86_VISWS || X86_VOYAGER)
1348 config X86_TRAMPOLINE
1350 depends on X86_SMP || (X86_VOYAGER && SMP)
1355 depends on X86 && !EMBEDDED