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