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
457 bool "Provide RTC interrupt"
458 depends on HPET_TIMER && RTC=y
461 bool "Symmetric multi-processing support"
463 This enables support for systems with more than one CPU. If you have
464 a system with only one CPU, like most personal computers, say N. If
465 you have a system with more than one CPU, say Y.
467 If you say N here, the kernel will run on single and multiprocessor
468 machines, but will use only one CPU of a multiprocessor machine. If
469 you say Y here, the kernel will run on many, but not all,
470 singleprocessor machines. On a singleprocessor machine, the kernel
471 will run faster if you say N here.
473 Note that if you say Y here and choose architecture "586" or
474 "Pentium" under "Processor family", the kernel will not work on 486
475 architectures. Similarly, multiprocessor kernels for the "PPro"
476 architecture may not work on all Pentium based boards.
478 People using multiprocessor machines who say Y here should also say
479 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
480 Management" code will be disabled if you say Y here.
482 See also the <file:Documentation/smp.txt>,
483 <file:Documentation/i386/IO-APIC.txt>,
484 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
485 <http://www.tldp.org/docs.html#howto>.
487 If you don't know what to do here, say N.
490 int "Maximum number of CPUs (2-255)"
493 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
496 This allows you to specify the maximum number of CPUs which this
497 kernel will support. The maximum supported value is 255 and the
498 minimum value which makes sense is 2.
500 This is purely to save memory - each supported CPU adds
501 approximately eight kilobytes to the kernel image.
504 bool "SMT (Hyperthreading) scheduler support"
508 SMT scheduler support improves the CPU scheduler's decision making
509 when dealing with Intel Pentium 4 chips with HyperThreading at a
510 cost of slightly increased overhead in some places. If unsure say
514 bool "Preemptible Kernel"
516 This option reduces the latency of the kernel when reacting to
517 real-time or interactive events by allowing a low priority process to
518 be preempted even if it is in kernel mode executing a system call.
519 This allows applications to run more reliably even when the system is
522 Say Y here if you are building a kernel for a desktop, embedded
523 or real-time system. Say N if you are unsure.
526 bool "Preempt The Big Kernel Lock"
530 This option reduces the latency of the kernel by making the
531 big kernel lock preemptible.
533 Say Y here if you are building a kernel for a desktop system.
534 Say N if you are unsure.
537 bool "Local APIC support on uniprocessors"
538 depends on !SMP && !(X86_VISWS || X86_VOYAGER)
540 A local APIC (Advanced Programmable Interrupt Controller) is an
541 integrated interrupt controller in the CPU. If you have a single-CPU
542 system which has a processor with a local APIC, you can say Y here to
543 enable and use it. If you say Y here even though your machine doesn't
544 have a local APIC, then the kernel will still run with no slowdown at
545 all. The local APIC supports CPU-generated self-interrupts (timer,
546 performance counters), and the NMI watchdog which detects hard
550 bool "IO-APIC support on uniprocessors"
551 depends on X86_UP_APIC
553 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
554 SMP-capable replacement for PC-style interrupt controllers. Most
555 SMP systems and many recent uniprocessor systems have one.
557 If you have a single-CPU system with an IO-APIC, you can say Y here
558 to use it. If you say Y here even though your machine doesn't have
559 an IO-APIC, then the kernel will still run with no slowdown at all.
561 config X86_LOCAL_APIC
563 depends on X86_UP_APIC || ((X86_VISWS || SMP) && !X86_VOYAGER)
568 depends on X86_UP_IOAPIC || (SMP && !(X86_VISWS || X86_VOYAGER))
571 config X86_VISWS_APIC
578 depends on (MWINCHIP3D || MWINCHIP2 || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MGEODEGX1) && !X86_NUMAQ
582 bool "Machine Check Exception"
583 depends on !X86_VOYAGER
585 Machine Check Exception support allows the processor to notify the
586 kernel if it detects a problem (e.g. overheating, component failure).
587 The action the kernel takes depends on the severity of the problem,
588 ranging from a warning message on the console, to halting the machine.
589 Your processor must be a Pentium or newer to support this - check the
590 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
591 have a design flaw which leads to false MCE events - hence MCE is
592 disabled on all P5 processors, unless explicitly enabled with "mce"
593 as a boot argument. Similarly, if MCE is built in and creates a
594 problem on some new non-standard machine, you can boot with "nomce"
595 to disable it. MCE support simply ignores non-MCE processors like
596 the 386 and 486, so nearly everyone can say Y here.
598 config X86_MCE_NONFATAL
599 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
602 Enabling this feature starts a timer that triggers every 5 seconds which
603 will look at the machine check registers to see if anything happened.
604 Non-fatal problems automatically get corrected (but still logged).
605 Disable this if you don't want to see these messages.
606 Seeing the messages this option prints out may be indicative of dying hardware,
607 or out-of-spec (ie, overclocked) hardware.
608 This option only does something on certain CPUs.
609 (AMD Athlon/Duron and Intel Pentium 4)
611 config X86_MCE_P4THERMAL
612 bool "check for P4 thermal throttling interrupt."
613 depends on X86_MCE && (X86_UP_APIC || SMP) && !X86_VISWS
615 Enabling this feature will cause a message to be printed when the P4
616 enters thermal throttling.
619 tristate "Toshiba Laptop support"
621 This adds a driver to safely access the System Management Mode of
622 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
623 not work on models with a Phoenix BIOS. The System Management Mode
624 is used to set the BIOS and power saving options on Toshiba portables.
626 For information on utilities to make use of this driver see the
627 Toshiba Linux utilities web site at:
628 <http://www.buzzard.org.uk/toshiba/>.
630 Say Y if you intend to run this kernel on a Toshiba portable.
634 tristate "Dell laptop support"
636 This adds a driver to safely access the System Management Mode
637 of the CPU on the Dell Inspiron 8000. The System Management Mode
638 is used to read cpu temperature and cooling fan status and to
639 control the fans on the I8K portables.
641 This driver has been tested only on the Inspiron 8000 but it may
642 also work with other Dell laptops. You can force loading on other
643 models by passing the parameter `force=1' to the module. Use at
646 For information on utilities to make use of this driver see the
647 I8K Linux utilities web site at:
648 <http://people.debian.org/~dz/i8k/>
650 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
653 config X86_REBOOTFIXUPS
654 bool "Enable X86 board specific fixups for reboot"
658 This enables chipset and/or board specific fixups to be done
659 in order to get reboot to work correctly. This is only needed on
660 some combinations of hardware and BIOS. The symptom, for which
661 this config is intended, is when reboot ends with a stalled/hung
664 Currently, the only fixup is for the Geode GX1/CS5530A/TROM2.1.
667 Say Y if you want to enable the fixup. Currently, it's safe to
668 enable this option even if you don't need it.
672 tristate "/dev/cpu/microcode - Intel IA32 CPU microcode support"
674 If you say Y here and also to "/dev file system support" in the
675 'File systems' section, you will be able to update the microcode on
676 Intel processors in the IA32 family, e.g. Pentium Pro, Pentium II,
677 Pentium III, Pentium 4, Xeon etc. You will obviously need the
678 actual microcode binary data itself which is not shipped with the
681 For latest news and information on obtaining all the required
682 ingredients for this driver, check:
683 <http://www.urbanmyth.org/microcode/>.
685 To compile this driver as a module, choose M here: the
686 module will be called microcode.
689 tristate "/dev/cpu/*/msr - Model-specific register support"
691 This device gives privileged processes access to the x86
692 Model-Specific Registers (MSRs). It is a character device with
693 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
694 MSR accesses are directed to a specific CPU on multi-processor
698 tristate "/dev/cpu/*/cpuid - CPU information support"
700 This device gives processes access to the x86 CPUID instruction to
701 be executed on a specific processor. It is a character device
702 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
705 source "drivers/firmware/Kconfig"
708 prompt "High Memory Support"
714 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
715 However, the address space of 32-bit x86 processors is only 4
716 Gigabytes large. That means that, if you have a large amount of
717 physical memory, not all of it can be "permanently mapped" by the
718 kernel. The physical memory that's not permanently mapped is called
721 If you are compiling a kernel which will never run on a machine with
722 more than 1 Gigabyte total physical RAM, answer "off" here (default
723 choice and suitable for most users). This will result in a "3GB/1GB"
724 split: 3GB are mapped so that each process sees a 3GB virtual memory
725 space and the remaining part of the 4GB virtual memory space is used
726 by the kernel to permanently map as much physical memory as
729 If the machine has between 1 and 4 Gigabytes physical RAM, then
732 If more than 4 Gigabytes is used then answer "64GB" here. This
733 selection turns Intel PAE (Physical Address Extension) mode on.
734 PAE implements 3-level paging on IA32 processors. PAE is fully
735 supported by Linux, PAE mode is implemented on all recent Intel
736 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
737 then the kernel will not boot on CPUs that don't support PAE!
739 The actual amount of total physical memory will either be
740 auto detected or can be forced by using a kernel command line option
741 such as "mem=256M". (Try "man bootparam" or see the documentation of
742 your boot loader (lilo or loadlin) about how to pass options to the
743 kernel at boot time.)
745 If unsure, say "off".
750 Select this if you have a 32-bit processor and between 1 and 4
751 gigabytes of physical RAM.
756 Select this if you have a 32-bit processor and more than 4
757 gigabytes of physical RAM.
763 depends on HIGHMEM64G || HIGHMEM4G
768 depends on HIGHMEM64G
771 # Common NUMA Features
773 bool "Numa Memory Allocation and Scheduler Support"
774 depends on SMP && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || (X86_SUMMIT && ACPI))
776 default y if (X86_NUMAQ || X86_SUMMIT)
778 # Need comments to help the hapless user trying to turn on NUMA support
779 comment "NUMA (NUMA-Q) requires SMP, 64GB highmem support"
780 depends on X86_NUMAQ && (!HIGHMEM64G || !SMP)
782 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
783 depends on X86_SUMMIT && (!HIGHMEM64G || !ACPI)
785 config HAVE_ARCH_BOOTMEM_NODE
790 config ARCH_HAVE_MEMORY_PRESENT
792 depends on DISCONTIGMEM
795 config NEED_NODE_MEMMAP_SIZE
797 depends on DISCONTIGMEM || SPARSEMEM
800 config HAVE_ARCH_ALLOC_REMAP
805 config ARCH_DISCONTIGMEM_ENABLE
809 config ARCH_DISCONTIGMEM_DEFAULT
813 config ARCH_SPARSEMEM_ENABLE
817 config ARCH_SELECT_MEMORY_MODEL
819 depends on ARCH_SPARSEMEM_ENABLE
823 config HAVE_ARCH_EARLY_PFN_TO_NID
829 bool "Allocate 3rd-level pagetables from highmem"
830 depends on HIGHMEM4G || HIGHMEM64G
832 The VM uses one page table entry for each page of physical memory.
833 For systems with a lot of RAM, this can be wasteful of precious
834 low memory. Setting this option will put user-space page table
835 entries in high memory.
837 config MATH_EMULATION
838 bool "Math emulation"
840 Linux can emulate a math coprocessor (used for floating point
841 operations) if you don't have one. 486DX and Pentium processors have
842 a math coprocessor built in, 486SX and 386 do not, unless you added
843 a 487DX or 387, respectively. (The messages during boot time can
844 give you some hints here ["man dmesg"].) Everyone needs either a
845 coprocessor or this emulation.
847 If you don't have a math coprocessor, you need to say Y here; if you
848 say Y here even though you have a coprocessor, the coprocessor will
849 be used nevertheless. (This behavior can be changed with the kernel
850 command line option "no387", which comes handy if your coprocessor
851 is broken. Try "man bootparam" or see the documentation of your boot
852 loader (lilo or loadlin) about how to pass options to the kernel at
853 boot time.) This means that it is a good idea to say Y here if you
854 intend to use this kernel on different machines.
856 More information about the internals of the Linux math coprocessor
857 emulation can be found in <file:arch/i386/math-emu/README>.
859 If you are not sure, say Y; apart from resulting in a 66 KB bigger
860 kernel, it won't hurt.
863 bool "MTRR (Memory Type Range Register) support"
865 On Intel P6 family processors (Pentium Pro, Pentium II and later)
866 the Memory Type Range Registers (MTRRs) may be used to control
867 processor access to memory ranges. This is most useful if you have
868 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
869 allows bus write transfers to be combined into a larger transfer
870 before bursting over the PCI/AGP bus. This can increase performance
871 of image write operations 2.5 times or more. Saying Y here creates a
872 /proc/mtrr file which may be used to manipulate your processor's
873 MTRRs. Typically the X server should use this.
875 This code has a reasonably generic interface so that similar
876 control registers on other processors can be easily supported
879 The Cyrix 6x86, 6x86MX and M II processors have Address Range
880 Registers (ARRs) which provide a similar functionality to MTRRs. For
881 these, the ARRs are used to emulate the MTRRs.
882 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
883 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
884 write-combining. All of these processors are supported by this code
885 and it makes sense to say Y here if you have one of them.
887 Saying Y here also fixes a problem with buggy SMP BIOSes which only
888 set the MTRRs for the boot CPU and not for the secondary CPUs. This
889 can lead to all sorts of problems, so it's good to say Y here.
891 You can safely say Y even if your machine doesn't have MTRRs, you'll
892 just add about 9 KB to your kernel.
894 See <file:Documentation/mtrr.txt> for more information.
897 bool "Boot from EFI support (EXPERIMENTAL)"
901 This enables the the kernel to boot on EFI platforms using
902 system configuration information passed to it from the firmware.
903 This also enables the kernel to use any EFI runtime services that are
904 available (such as the EFI variable services).
906 This option is only useful on systems that have EFI firmware
907 and will result in a kernel image that is ~8k larger. In addition,
908 you must use the latest ELILO loader available at
909 <http://elilo.sourceforge.net> in order to take advantage of
910 kernel initialization using EFI information (neither GRUB nor LILO know
911 anything about EFI). However, even with this option, the resultant
912 kernel should continue to boot on existing non-EFI platforms.
915 bool "Enable kernel irq balancing"
916 depends on SMP && X86_IO_APIC
919 The default yes will allow the kernel to do irq load balancing.
920 Saying no will keep the kernel from doing irq load balancing.
924 depends on (SMP || PREEMPT) && X86_CMPXCHG
927 # turning this on wastes a bunch of space.
928 # Summit needs it only when NUMA is on
931 depends on (((X86_SUMMIT || X86_GENERICARCH) && NUMA) || (X86 && EFI))
935 bool "Use register arguments (EXPERIMENTAL)"
936 depends on EXPERIMENTAL
939 Compile the kernel with -mregparm=3. This uses a different ABI
940 and passes the first three arguments of a function call in registers.
941 This will probably break binary only modules.
943 This feature is only enabled for gcc-3.0 and later - earlier compilers
944 generate incorrect output with certain kernel constructs when
948 bool "Enable seccomp to safely compute untrusted bytecode"
952 This kernel feature is useful for number crunching applications
953 that may need to compute untrusted bytecode during their
954 execution. By using pipes or other transports made available to
955 the process as file descriptors supporting the read/write
956 syscalls, it's possible to isolate those applications in
957 their own address space using seccomp. Once seccomp is
958 enabled via /proc/<pid>/seccomp, it cannot be disabled
959 and the task is only allowed to execute a few safe syscalls
960 defined by each seccomp mode.
962 If unsure, say Y. Only embedded should say N here.
964 source kernel/Kconfig.hz
969 menu "Power management options (ACPI, APM)"
970 depends on !X86_VOYAGER
972 source kernel/power/Kconfig
974 source "drivers/acpi/Kconfig"
976 menu "APM (Advanced Power Management) BIOS Support"
977 depends on PM && !X86_VISWS
980 tristate "APM (Advanced Power Management) BIOS support"
983 APM is a BIOS specification for saving power using several different
984 techniques. This is mostly useful for battery powered laptops with
985 APM compliant BIOSes. If you say Y here, the system time will be
986 reset after a RESUME operation, the /proc/apm device will provide
987 battery status information, and user-space programs will receive
988 notification of APM "events" (e.g. battery status change).
990 If you select "Y" here, you can disable actual use of the APM
991 BIOS by passing the "apm=off" option to the kernel at boot time.
993 Note that the APM support is almost completely disabled for
994 machines with more than one CPU.
996 In order to use APM, you will need supporting software. For location
997 and more information, read <file:Documentation/pm.txt> and the
998 Battery Powered Linux mini-HOWTO, available from
999 <http://www.tldp.org/docs.html#howto>.
1001 This driver does not spin down disk drives (see the hdparm(8)
1002 manpage ("man 8 hdparm") for that), and it doesn't turn off
1003 VESA-compliant "green" monitors.
1005 This driver does not support the TI 4000M TravelMate and the ACER
1006 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1007 desktop machines also don't have compliant BIOSes, and this driver
1008 may cause those machines to panic during the boot phase.
1010 Generally, if you don't have a battery in your machine, there isn't
1011 much point in using this driver and you should say N. If you get
1012 random kernel OOPSes or reboots that don't seem to be related to
1013 anything, try disabling/enabling this option (or disabling/enabling
1016 Some other things you should try when experiencing seemingly random,
1019 1) make sure that you have enough swap space and that it is
1021 2) pass the "no-hlt" option to the kernel
1022 3) switch on floating point emulation in the kernel and pass
1023 the "no387" option to the kernel
1024 4) pass the "floppy=nodma" option to the kernel
1025 5) pass the "mem=4M" option to the kernel (thereby disabling
1026 all but the first 4 MB of RAM)
1027 6) make sure that the CPU is not over clocked.
1028 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1029 8) disable the cache from your BIOS settings
1030 9) install a fan for the video card or exchange video RAM
1031 10) install a better fan for the CPU
1032 11) exchange RAM chips
1033 12) exchange the motherboard.
1035 To compile this driver as a module, choose M here: the
1036 module will be called apm.
1038 config APM_IGNORE_USER_SUSPEND
1039 bool "Ignore USER SUSPEND"
1042 This option will ignore USER SUSPEND requests. On machines with a
1043 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1044 series notebooks, it is necessary to say Y because of a BIOS bug.
1046 config APM_DO_ENABLE
1047 bool "Enable PM at boot time"
1050 Enable APM features at boot time. From page 36 of the APM BIOS
1051 specification: "When disabled, the APM BIOS does not automatically
1052 power manage devices, enter the Standby State, enter the Suspend
1053 State, or take power saving steps in response to CPU Idle calls."
1054 This driver will make CPU Idle calls when Linux is idle (unless this
1055 feature is turned off -- see "Do CPU IDLE calls", below). This
1056 should always save battery power, but more complicated APM features
1057 will be dependent on your BIOS implementation. You may need to turn
1058 this option off if your computer hangs at boot time when using APM
1059 support, or if it beeps continuously instead of suspending. Turn
1060 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1061 T400CDT. This is off by default since most machines do fine without
1065 bool "Make CPU Idle calls when idle"
1068 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1069 On some machines, this can activate improved power savings, such as
1070 a slowed CPU clock rate, when the machine is idle. These idle calls
1071 are made after the idle loop has run for some length of time (e.g.,
1072 333 mS). On some machines, this will cause a hang at boot time or
1073 whenever the CPU becomes idle. (On machines with more than one CPU,
1074 this option does nothing.)
1076 config APM_DISPLAY_BLANK
1077 bool "Enable console blanking using APM"
1080 Enable console blanking using the APM. Some laptops can use this to
1081 turn off the LCD backlight when the screen blanker of the Linux
1082 virtual console blanks the screen. Note that this is only used by
1083 the virtual console screen blanker, and won't turn off the backlight
1084 when using the X Window system. This also doesn't have anything to
1085 do with your VESA-compliant power-saving monitor. Further, this
1086 option doesn't work for all laptops -- it might not turn off your
1087 backlight at all, or it might print a lot of errors to the console,
1088 especially if you are using gpm.
1090 config APM_RTC_IS_GMT
1091 bool "RTC stores time in GMT"
1094 Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
1095 stores the time in GMT (Greenwich Mean Time). Say N if your RTC
1098 It is in fact recommended to store GMT in your RTC, because then you
1099 don't have to worry about daylight savings time changes. The only
1100 reason not to use GMT in your RTC is if you also run a broken OS
1101 that doesn't understand GMT.
1103 config APM_ALLOW_INTS
1104 bool "Allow interrupts during APM BIOS calls"
1107 Normally we disable external interrupts while we are making calls to
1108 the APM BIOS as a measure to lessen the effects of a badly behaving
1109 BIOS implementation. The BIOS should reenable interrupts if it
1110 needs to. Unfortunately, some BIOSes do not -- especially those in
1111 many of the newer IBM Thinkpads. If you experience hangs when you
1112 suspend, try setting this to Y. Otherwise, say N.
1114 config APM_REAL_MODE_POWER_OFF
1115 bool "Use real mode APM BIOS call to power off"
1118 Use real mode APM BIOS calls to switch off the computer. This is
1119 a work-around for a number of buggy BIOSes. Switch this option on if
1120 your computer crashes instead of powering off properly.
1124 source "arch/i386/kernel/cpu/cpufreq/Kconfig"
1128 menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
1131 bool "PCI support" if !X86_VISWS
1132 depends on !X86_VOYAGER
1133 default y if X86_VISWS
1135 Find out whether you have a PCI motherboard. PCI is the name of a
1136 bus system, i.e. the way the CPU talks to the other stuff inside
1137 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1138 VESA. If you have PCI, say Y, otherwise N.
1140 The PCI-HOWTO, available from
1141 <http://www.tldp.org/docs.html#howto>, contains valuable
1142 information about which PCI hardware does work under Linux and which
1146 prompt "PCI access mode"
1147 depends on PCI && !X86_VISWS
1150 On PCI systems, the BIOS can be used to detect the PCI devices and
1151 determine their configuration. However, some old PCI motherboards
1152 have BIOS bugs and may crash if this is done. Also, some embedded
1153 PCI-based systems don't have any BIOS at all. Linux can also try to
1154 detect the PCI hardware directly without using the BIOS.
1156 With this option, you can specify how Linux should detect the
1157 PCI devices. If you choose "BIOS", the BIOS will be used,
1158 if you choose "Direct", the BIOS won't be used, and if you
1159 choose "MMConfig", then PCI Express MMCONFIG will be used.
1160 If you choose "Any", the kernel will try MMCONFIG, then the
1161 direct access method and falls back to the BIOS if that doesn't
1162 work. If unsure, go with the default, which is "Any".
1167 config PCI_GOMMCONFIG
1180 depends on !X86_VISWS && PCI && (PCI_GOBIOS || PCI_GOANY)
1185 depends on PCI && ((PCI_GODIRECT || PCI_GOANY) || X86_VISWS)
1190 depends on PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1194 source "drivers/pci/pcie/Kconfig"
1196 source "drivers/pci/Kconfig"
1204 depends on !(X86_VOYAGER || X86_VISWS)
1206 Find out whether you have ISA slots on your motherboard. ISA is the
1207 name of a bus system, i.e. the way the CPU talks to the other stuff
1208 inside your box. Other bus systems are PCI, EISA, MicroChannel
1209 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1210 newer boards don't support it. If you have ISA, say Y, otherwise N.
1216 The Extended Industry Standard Architecture (EISA) bus was
1217 developed as an open alternative to the IBM MicroChannel bus.
1219 The EISA bus provided some of the features of the IBM MicroChannel
1220 bus while maintaining backward compatibility with cards made for
1221 the older ISA bus. The EISA bus saw limited use between 1988 and
1222 1995 when it was made obsolete by the PCI bus.
1224 Say Y here if you are building a kernel for an EISA-based machine.
1228 source "drivers/eisa/Kconfig"
1231 bool "MCA support" if !(X86_VISWS || X86_VOYAGER)
1232 default y if X86_VOYAGER
1234 MicroChannel Architecture is found in some IBM PS/2 machines and
1235 laptops. It is a bus system similar to PCI or ISA. See
1236 <file:Documentation/mca.txt> (and especially the web page given
1237 there) before attempting to build an MCA bus kernel.
1239 source "drivers/mca/Kconfig"
1242 tristate "NatSemi SCx200 support"
1243 depends on !X86_VOYAGER
1245 This provides basic support for the National Semiconductor SCx200
1246 processor. Right now this is just a driver for the GPIO pins.
1248 If you don't know what to do here, say N.
1250 This support is also available as a module. If compiled as a
1251 module, it will be called scx200.
1254 bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
1255 depends on SMP && HOTPLUG && EXPERIMENTAL
1257 Say Y here to experiment with turning CPUs off and on. CPUs
1258 can be controlled through /sys/devices/system/cpu.
1262 source "drivers/pcmcia/Kconfig"
1264 source "drivers/pci/hotplug/Kconfig"
1268 menu "Executable file formats"
1270 source "fs/Kconfig.binfmt"
1274 source "drivers/Kconfig"
1278 source "arch/i386/oprofile/Kconfig"
1280 source "arch/i386/Kconfig.debug"
1282 source "security/Kconfig"
1284 source "crypto/Kconfig"
1286 source "lib/Kconfig"
1289 # Use the generic interrupt handling code in kernel/irq/:
1291 config GENERIC_HARDIRQS
1295 config GENERIC_IRQ_PROBE
1301 depends on SMP && !X86_VOYAGER
1306 depends on SMP && !(X86_VISWS || X86_VOYAGER)
1309 config X86_BIOS_REBOOT
1311 depends on !(X86_VISWS || X86_VOYAGER)
1314 config X86_TRAMPOLINE
1316 depends on X86_SMP || (X86_VOYAGER && SMP)
1321 depends on X86 && !EMBEDDED