2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
22 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IOREMAP_PROT
27 select ARCH_WANT_OPTIONAL_GPIOLIB
28 select HAVE_KRETPROBES
29 select HAVE_DYNAMIC_FTRACE
31 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
32 select HAVE_ARCH_KGDB if !X86_VOYAGER
33 select HAVE_ARCH_TRACEHOOK
34 select HAVE_GENERIC_DMA_COHERENT if X86_32
35 select HAVE_EFFICIENT_UNALIGNED_ACCESS
39 default "arch/x86/configs/i386_defconfig" if X86_32
40 default "arch/x86/configs/x86_64_defconfig" if X86_64
45 config GENERIC_CMOS_UPDATE
48 config CLOCKSOURCE_WATCHDOG
51 config GENERIC_CLOCKEVENTS
54 config GENERIC_CLOCKEVENTS_BROADCAST
56 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
58 config LOCKDEP_SUPPORT
61 config STACKTRACE_SUPPORT
64 config HAVE_LATENCYTOP_SUPPORT
67 config FAST_CMPXCHG_LOCAL
80 config GENERIC_ISA_DMA
90 config GENERIC_HWEIGHT
96 config ARCH_MAY_HAVE_PC_FDC
99 config RWSEM_GENERIC_SPINLOCK
102 config RWSEM_XCHGADD_ALGORITHM
105 config ARCH_HAS_CPU_IDLE_WAIT
108 config GENERIC_CALIBRATE_DELAY
111 config GENERIC_TIME_VSYSCALL
115 config ARCH_HAS_CPU_RELAX
118 config ARCH_HAS_CACHE_LINE_SIZE
121 config HAVE_SETUP_PER_CPU_AREA
122 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
124 config HAVE_CPUMASK_OF_CPU_MAP
127 config ARCH_HIBERNATION_POSSIBLE
129 depends on !SMP || !X86_VOYAGER
131 config ARCH_SUSPEND_POSSIBLE
133 depends on !X86_VOYAGER
139 config ARCH_POPULATES_NODE_MAP
146 config ARCH_SUPPORTS_OPTIMIZED_INLINING
149 # Use the generic interrupt handling code in kernel/irq/:
150 config GENERIC_HARDIRQS
154 config GENERIC_IRQ_PROBE
158 config GENERIC_PENDING_IRQ
160 depends on GENERIC_HARDIRQS && SMP
165 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
166 select USE_GENERIC_SMP_HELPERS
171 depends on X86_32 && SMP
175 depends on X86_64 && SMP
180 depends on (X86_32 && !X86_VOYAGER) || X86_64
183 config X86_BIOS_REBOOT
185 depends on !X86_VOYAGER
188 config X86_TRAMPOLINE
190 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
195 source "init/Kconfig"
197 menu "Processor type and features"
199 source "kernel/time/Kconfig"
202 bool "Symmetric multi-processing support"
204 This enables support for systems with more than one CPU. If you have
205 a system with only one CPU, like most personal computers, say N. If
206 you have a system with more than one CPU, say Y.
208 If you say N here, the kernel will run on single and multiprocessor
209 machines, but will use only one CPU of a multiprocessor machine. If
210 you say Y here, the kernel will run on many, but not all,
211 singleprocessor machines. On a singleprocessor machine, the kernel
212 will run faster if you say N here.
214 Note that if you say Y here and choose architecture "586" or
215 "Pentium" under "Processor family", the kernel will not work on 486
216 architectures. Similarly, multiprocessor kernels for the "PPro"
217 architecture may not work on all Pentium based boards.
219 People using multiprocessor machines who say Y here should also say
220 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
221 Management" code will be disabled if you say Y here.
223 See also <file:Documentation/i386/IO-APIC.txt>,
224 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
225 <http://www.tldp.org/docs.html#howto>.
227 If you don't know what to do here, say N.
229 config X86_FIND_SMP_CONFIG
231 depends on X86_MPPARSE || X86_VOYAGER
236 bool "Enable MPS table"
237 depends on X86_LOCAL_APIC
239 For old smp systems that do not have proper acpi support. Newer systems
240 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
246 depends on X86_LOCAL_APIC
250 prompt "Subarchitecture Type"
256 Choose this option if your computer is a standard PC or compatible.
262 Select this for an AMD Elan processor.
264 Do not use this option for K6/Athlon/Opteron processors!
266 If unsure, choose "PC-compatible" instead.
270 depends on X86_32 && (SMP || BROKEN) && !PCI
272 Voyager is an MCA-based 32-way capable SMP architecture proprietary
273 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
277 If you do not specifically know you have a Voyager based machine,
278 say N here, otherwise the kernel you build will not be bootable.
280 config X86_GENERICARCH
281 bool "Generic architecture"
284 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
285 subarchitectures. It is intended for a generic binary kernel.
286 if you select them all, kernel will probe it one by one. and will
292 bool "NUMAQ (IBM/Sequent)"
293 depends on SMP && X86_32 && PCI && X86_MPPARSE
296 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
297 NUMA multiquad box. This changes the way that processors are
298 bootstrapped, and uses Clustered Logical APIC addressing mode instead
299 of Flat Logical. You will need a new lynxer.elf file to flash your
300 firmware with - send email to <Martin.Bligh@us.ibm.com>.
303 bool "Summit/EXA (IBM x440)"
304 depends on X86_32 && SMP
306 This option is needed for IBM systems that use the Summit/EXA chipset.
307 In particular, it is needed for the x440.
310 bool "Support for Unisys ES7000 IA32 series"
311 depends on X86_32 && SMP
313 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
314 supposed to run on an IA32-based Unisys ES7000 system.
317 bool "Support for big SMP systems with more than 8 CPUs"
318 depends on X86_32 && SMP
320 This option is needed for the systems that have more than 8 CPUs
321 and if the system is not of any sub-arch type above.
326 bool "Support for ScaleMP vSMP"
328 depends on X86_64 && PCI
330 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
331 supposed to run on these EM64T-based machines. Only choose this option
332 if you have one of these machines.
337 bool "SGI 320/540 (Visual Workstation)"
338 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
340 The SGI Visual Workstation series is an IA32-based workstation
341 based on SGI systems chips with some legacy PC hardware attached.
343 Say Y here to create a kernel to run on the SGI 320 or 540.
345 A kernel compiled for the Visual Workstation will run on general
346 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
349 bool "RDC R-321x SoC"
352 select X86_REBOOTFIXUPS
354 This option is needed for RDC R-321x system-on-chip, also known
356 If you don't have one of these chips, you should say N here.
358 config SCHED_NO_NO_OMIT_FRAME_POINTER
360 prompt "Single-depth WCHAN output"
363 Calculate simpler /proc/<PID>/wchan values. If this option
364 is disabled then wchan values will recurse back to the
365 caller function. This provides more accurate wchan values,
366 at the expense of slightly more scheduling overhead.
368 If in doubt, say "Y".
370 menuconfig PARAVIRT_GUEST
371 bool "Paravirtualized guest support"
373 Say Y here to get to see options related to running Linux under
374 various hypervisors. This option alone does not add any kernel code.
376 If you say N, all options in this submenu will be skipped and disabled.
380 source "arch/x86/xen/Kconfig"
383 bool "VMI Guest support"
386 depends on !X86_VOYAGER
388 VMI provides a paravirtualized interface to the VMware ESX server
389 (it could be used by other hypervisors in theory too, but is not
390 at the moment), by linking the kernel to a GPL-ed ROM module
391 provided by the hypervisor.
394 bool "KVM paravirtualized clock"
396 select PARAVIRT_CLOCK
397 depends on !X86_VOYAGER
399 Turning on this option will allow you to run a paravirtualized clock
400 when running over the KVM hypervisor. Instead of relying on a PIT
401 (or probably other) emulation by the underlying device model, the host
402 provides the guest with timing infrastructure such as time of day, and
406 bool "KVM Guest support"
408 depends on !X86_VOYAGER
410 This option enables various optimizations for running under the KVM
413 source "arch/x86/lguest/Kconfig"
416 bool "Enable paravirtualization code"
417 depends on !X86_VOYAGER
419 This changes the kernel so it can modify itself when it is run
420 under a hypervisor, potentially improving performance significantly
421 over full virtualization. However, when run without a hypervisor
422 the kernel is theoretically slower and slightly larger.
424 config PARAVIRT_CLOCK
430 config PARAVIRT_DEBUG
431 bool "paravirt-ops debugging"
432 depends on PARAVIRT && DEBUG_KERNEL
434 Enable to debug paravirt_ops internals. Specifically, BUG if
435 a paravirt_op is missing when it is called.
440 This option adds a kernel parameter 'memtest', which allows memtest
442 memtest=0, mean disabled; -- default
443 memtest=1, mean do 1 test pattern;
445 memtest=4, mean do 4 test patterns.
446 If you are unsure how to answer this question, answer N.
448 config X86_SUMMIT_NUMA
450 depends on X86_32 && NUMA && X86_GENERICARCH
452 config X86_CYCLONE_TIMER
454 depends on X86_GENERICARCH
456 config ES7000_CLUSTERED_APIC
458 depends on SMP && X86_ES7000 && MPENTIUMIII
460 source "arch/x86/Kconfig.cpu"
464 prompt "HPET Timer Support" if X86_32
466 Use the IA-PC HPET (High Precision Event Timer) to manage
467 time in preference to the PIT and RTC, if a HPET is
469 HPET is the next generation timer replacing legacy 8254s.
470 The HPET provides a stable time base on SMP
471 systems, unlike the TSC, but it is more expensive to access,
472 as it is off-chip. You can find the HPET spec at
473 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
475 You can safely choose Y here. However, HPET will only be
476 activated if the platform and the BIOS support this feature.
477 Otherwise the 8254 will be used for timing services.
479 Choose N to continue using the legacy 8254 timer.
481 config HPET_EMULATE_RTC
483 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
485 # Mark as embedded because too many people got it wrong.
486 # The code disables itself when not needed.
489 bool "Enable DMI scanning" if EMBEDDED
491 Enabled scanning of DMI to identify machine quirks. Say Y
492 here unless you have verified that your setup is not
493 affected by entries in the DMI blacklist. Required by PNP
497 bool "GART IOMMU support" if EMBEDDED
501 depends on X86_64 && PCI
503 Support for full DMA access of devices with 32bit memory access only
504 on systems with more than 3GB. This is usually needed for USB,
505 sound, many IDE/SATA chipsets and some other devices.
506 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
507 based hardware IOMMU and a software bounce buffer based IOMMU used
508 on Intel systems and as fallback.
509 The code is only active when needed (enough memory and limited
510 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
514 bool "IBM Calgary IOMMU support"
516 depends on X86_64 && PCI && EXPERIMENTAL
518 Support for hardware IOMMUs in IBM's xSeries x366 and x460
519 systems. Needed to run systems with more than 3GB of memory
520 properly with 32-bit PCI devices that do not support DAC
521 (Double Address Cycle). Calgary also supports bus level
522 isolation, where all DMAs pass through the IOMMU. This
523 prevents them from going anywhere except their intended
524 destination. This catches hard-to-find kernel bugs and
525 mis-behaving drivers and devices that do not use the DMA-API
526 properly to set up their DMA buffers. The IOMMU can be
527 turned off at boot time with the iommu=off parameter.
528 Normally the kernel will make the right choice by itself.
531 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
533 prompt "Should Calgary be enabled by default?"
534 depends on CALGARY_IOMMU
536 Should Calgary be enabled by default? if you choose 'y', Calgary
537 will be used (if it exists). If you choose 'n', Calgary will not be
538 used even if it exists. If you choose 'n' and would like to use
539 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
543 bool "AMD IOMMU support"
546 depends on X86_64 && PCI && ACPI
548 With this option you can enable support for AMD IOMMU hardware in
549 your system. An IOMMU is a hardware component which provides
550 remapping of DMA memory accesses from devices. With an AMD IOMMU you
551 can isolate the the DMA memory of different devices and protect the
552 system from misbehaving device drivers or hardware.
554 You can find out if your system has an AMD IOMMU if you look into
555 your BIOS for an option to enable it or if you have an IVRS ACPI
558 # need this always selected by IOMMU for the VIA workaround
562 Support for software bounce buffers used on x86-64 systems
563 which don't have a hardware IOMMU (e.g. the current generation
564 of Intel's x86-64 CPUs). Using this PCI devices which can only
565 access 32-bits of memory can be used on systems with more than
566 3 GB of memory. If unsure, say Y.
569 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
572 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
573 depends on X86_64 && SMP && BROKEN
576 Configure maximum number of CPUS and NUMA Nodes for this architecture.
580 int "Maximum number of CPUs (2-512)" if !MAXSMP
583 default "4096" if MAXSMP
584 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
587 This allows you to specify the maximum number of CPUs which this
588 kernel will support. The maximum supported value is 512 and the
589 minimum value which makes sense is 2.
591 This is purely to save memory - each supported CPU adds
592 approximately eight kilobytes to the kernel image.
595 bool "SMT (Hyperthreading) scheduler support"
598 SMT scheduler support improves the CPU scheduler's decision making
599 when dealing with Intel Pentium 4 chips with HyperThreading at a
600 cost of slightly increased overhead in some places. If unsure say
605 prompt "Multi-core scheduler support"
608 Multi-core scheduler support improves the CPU scheduler's decision
609 making when dealing with multi-core CPU chips at a cost of slightly
610 increased overhead in some places. If unsure say N here.
612 source "kernel/Kconfig.preempt"
615 bool "Local APIC support on uniprocessors"
616 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
618 A local APIC (Advanced Programmable Interrupt Controller) is an
619 integrated interrupt controller in the CPU. If you have a single-CPU
620 system which has a processor with a local APIC, you can say Y here to
621 enable and use it. If you say Y here even though your machine doesn't
622 have a local APIC, then the kernel will still run with no slowdown at
623 all. The local APIC supports CPU-generated self-interrupts (timer,
624 performance counters), and the NMI watchdog which detects hard
628 bool "IO-APIC support on uniprocessors"
629 depends on X86_UP_APIC
631 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
632 SMP-capable replacement for PC-style interrupt controllers. Most
633 SMP systems and many recent uniprocessor systems have one.
635 If you have a single-CPU system with an IO-APIC, you can say Y here
636 to use it. If you say Y here even though your machine doesn't have
637 an IO-APIC, then the kernel will still run with no slowdown at all.
639 config X86_LOCAL_APIC
641 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
645 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
647 config X86_VISWS_APIC
649 depends on X86_32 && X86_VISWS
652 bool "Machine Check Exception"
653 depends on !X86_VOYAGER
655 Machine Check Exception support allows the processor to notify the
656 kernel if it detects a problem (e.g. overheating, component failure).
657 The action the kernel takes depends on the severity of the problem,
658 ranging from a warning message on the console, to halting the machine.
659 Your processor must be a Pentium or newer to support this - check the
660 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
661 have a design flaw which leads to false MCE events - hence MCE is
662 disabled on all P5 processors, unless explicitly enabled with "mce"
663 as a boot argument. Similarly, if MCE is built in and creates a
664 problem on some new non-standard machine, you can boot with "nomce"
665 to disable it. MCE support simply ignores non-MCE processors like
666 the 386 and 486, so nearly everyone can say Y here.
670 prompt "Intel MCE features"
671 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
673 Additional support for intel specific MCE features such as
678 prompt "AMD MCE features"
679 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
681 Additional support for AMD specific MCE features such as
682 the DRAM Error Threshold.
684 config X86_MCE_NONFATAL
685 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
686 depends on X86_32 && X86_MCE
688 Enabling this feature starts a timer that triggers every 5 seconds which
689 will look at the machine check registers to see if anything happened.
690 Non-fatal problems automatically get corrected (but still logged).
691 Disable this if you don't want to see these messages.
692 Seeing the messages this option prints out may be indicative of dying
693 or out-of-spec (ie, overclocked) hardware.
694 This option only does something on certain CPUs.
695 (AMD Athlon/Duron and Intel Pentium 4)
697 config X86_MCE_P4THERMAL
698 bool "check for P4 thermal throttling interrupt."
699 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
701 Enabling this feature will cause a message to be printed when the P4
702 enters thermal throttling.
705 bool "Enable VM86 support" if EMBEDDED
709 This option is required by programs like DOSEMU to run 16-bit legacy
710 code on X86 processors. It also may be needed by software like
711 XFree86 to initialize some video cards via BIOS. Disabling this
712 option saves about 6k.
715 tristate "Toshiba Laptop support"
718 This adds a driver to safely access the System Management Mode of
719 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
720 not work on models with a Phoenix BIOS. The System Management Mode
721 is used to set the BIOS and power saving options on Toshiba portables.
723 For information on utilities to make use of this driver see the
724 Toshiba Linux utilities web site at:
725 <http://www.buzzard.org.uk/toshiba/>.
727 Say Y if you intend to run this kernel on a Toshiba portable.
731 tristate "Dell laptop support"
733 This adds a driver to safely access the System Management Mode
734 of the CPU on the Dell Inspiron 8000. The System Management Mode
735 is used to read cpu temperature and cooling fan status and to
736 control the fans on the I8K portables.
738 This driver has been tested only on the Inspiron 8000 but it may
739 also work with other Dell laptops. You can force loading on other
740 models by passing the parameter `force=1' to the module. Use at
743 For information on utilities to make use of this driver see the
744 I8K Linux utilities web site at:
745 <http://people.debian.org/~dz/i8k/>
747 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
750 config X86_REBOOTFIXUPS
751 bool "Enable X86 board specific fixups for reboot"
754 This enables chipset and/or board specific fixups to be done
755 in order to get reboot to work correctly. This is only needed on
756 some combinations of hardware and BIOS. The symptom, for which
757 this config is intended, is when reboot ends with a stalled/hung
760 Currently, the only fixup is for the Geode machines using
761 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
763 Say Y if you want to enable the fixup. Currently, it's safe to
764 enable this option even if you don't need it.
768 tristate "/dev/cpu/microcode - microcode support"
771 If you say Y here, you will be able to update the microcode on
772 certain Intel and AMD processors. The Intel support is for the
773 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
774 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
775 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
776 You will obviously need the actual microcode binary data itself
777 which is not shipped with the Linux kernel.
779 This option selects the general module only, you need to select
780 at least one vendor specific module as well.
782 To compile this driver as a module, choose M here: the
783 module will be called microcode.
785 config MICROCODE_INTEL
786 bool "Intel microcode patch loading support"
791 This options enables microcode patch loading support for Intel
794 For latest news and information on obtaining all the required
795 Intel ingredients for this driver, check:
796 <http://www.urbanmyth.org/microcode/>.
799 bool "AMD microcode patch loading support"
803 If you select this option, microcode patch loading support for AMD
804 processors will be enabled.
806 config MICROCODE_OLD_INTERFACE
811 tristate "/dev/cpu/*/msr - Model-specific register support"
813 This device gives privileged processes access to the x86
814 Model-Specific Registers (MSRs). It is a character device with
815 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
816 MSR accesses are directed to a specific CPU on multi-processor
820 tristate "/dev/cpu/*/cpuid - CPU information support"
822 This device gives processes access to the x86 CPUID instruction to
823 be executed on a specific processor. It is a character device
824 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
828 prompt "High Memory Support"
829 default HIGHMEM4G if !X86_NUMAQ
830 default HIGHMEM64G if X86_NUMAQ
835 depends on !X86_NUMAQ
837 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
838 However, the address space of 32-bit x86 processors is only 4
839 Gigabytes large. That means that, if you have a large amount of
840 physical memory, not all of it can be "permanently mapped" by the
841 kernel. The physical memory that's not permanently mapped is called
844 If you are compiling a kernel which will never run on a machine with
845 more than 1 Gigabyte total physical RAM, answer "off" here (default
846 choice and suitable for most users). This will result in a "3GB/1GB"
847 split: 3GB are mapped so that each process sees a 3GB virtual memory
848 space and the remaining part of the 4GB virtual memory space is used
849 by the kernel to permanently map as much physical memory as
852 If the machine has between 1 and 4 Gigabytes physical RAM, then
855 If more than 4 Gigabytes is used then answer "64GB" here. This
856 selection turns Intel PAE (Physical Address Extension) mode on.
857 PAE implements 3-level paging on IA32 processors. PAE is fully
858 supported by Linux, PAE mode is implemented on all recent Intel
859 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
860 then the kernel will not boot on CPUs that don't support PAE!
862 The actual amount of total physical memory will either be
863 auto detected or can be forced by using a kernel command line option
864 such as "mem=256M". (Try "man bootparam" or see the documentation of
865 your boot loader (lilo or loadlin) about how to pass options to the
866 kernel at boot time.)
868 If unsure, say "off".
872 depends on !X86_NUMAQ
874 Select this if you have a 32-bit processor and between 1 and 4
875 gigabytes of physical RAM.
879 depends on !M386 && !M486
882 Select this if you have a 32-bit processor and more than 4
883 gigabytes of physical RAM.
888 depends on EXPERIMENTAL
889 prompt "Memory split" if EMBEDDED
893 Select the desired split between kernel and user memory.
895 If the address range available to the kernel is less than the
896 physical memory installed, the remaining memory will be available
897 as "high memory". Accessing high memory is a little more costly
898 than low memory, as it needs to be mapped into the kernel first.
899 Note that increasing the kernel address space limits the range
900 available to user programs, making the address space there
901 tighter. Selecting anything other than the default 3G/1G split
902 will also likely make your kernel incompatible with binary-only
905 If you are not absolutely sure what you are doing, leave this
909 bool "3G/1G user/kernel split"
910 config VMSPLIT_3G_OPT
912 bool "3G/1G user/kernel split (for full 1G low memory)"
914 bool "2G/2G user/kernel split"
915 config VMSPLIT_2G_OPT
917 bool "2G/2G user/kernel split (for full 2G low memory)"
919 bool "1G/3G user/kernel split"
924 default 0xB0000000 if VMSPLIT_3G_OPT
925 default 0x80000000 if VMSPLIT_2G
926 default 0x78000000 if VMSPLIT_2G_OPT
927 default 0x40000000 if VMSPLIT_1G
933 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
936 bool "PAE (Physical Address Extension) Support"
937 depends on X86_32 && !HIGHMEM4G
938 select RESOURCES_64BIT
940 PAE is required for NX support, and furthermore enables
941 larger swapspace support for non-overcommit purposes. It
942 has the cost of more pagetable lookup overhead, and also
943 consumes more pagetable space per process.
945 # Common NUMA Features
947 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
949 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
951 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
953 Enable NUMA (Non Uniform Memory Access) support.
954 The kernel will try to allocate memory used by a CPU on the
955 local memory controller of the CPU and add some more
956 NUMA awareness to the kernel.
958 For 32-bit this is currently highly experimental and should be only
959 used for kernel development. It might also cause boot failures.
960 For 64-bit this is recommended on all multiprocessor Opteron systems.
961 If the system is EM64T, you should say N unless your system is
964 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
965 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
969 prompt "Old style AMD Opteron NUMA detection"
970 depends on X86_64 && NUMA && PCI
972 Enable K8 NUMA node topology detection. You should say Y here if
973 you have a multi processor AMD K8 system. This uses an old
974 method to read the NUMA configuration directly from the builtin
975 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
976 instead, which also takes priority if both are compiled in.
978 config X86_64_ACPI_NUMA
980 prompt "ACPI NUMA detection"
981 depends on X86_64 && NUMA && ACPI && PCI
984 Enable ACPI SRAT based node topology detection.
986 # Some NUMA nodes have memory ranges that span
987 # other nodes. Even though a pfn is valid and
988 # between a node's start and end pfns, it may not
989 # reside on that node. See memmap_init_zone()
991 config NODES_SPAN_OTHER_NODES
993 depends on X86_64_ACPI_NUMA
996 bool "NUMA emulation"
997 depends on X86_64 && NUMA
999 Enable NUMA emulation. A flat machine will be split
1000 into virtual nodes when booted with "numa=fake=N", where N is the
1001 number of nodes. This is only useful for debugging.
1004 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1006 default "9" if MAXSMP
1007 default "6" if X86_64
1008 default "4" if X86_NUMAQ
1010 depends on NEED_MULTIPLE_NODES
1012 Specify the maximum number of NUMA Nodes available on the target
1013 system. Increases memory reserved to accomodate various tables.
1015 config HAVE_ARCH_BOOTMEM_NODE
1017 depends on X86_32 && NUMA
1019 config ARCH_HAVE_MEMORY_PRESENT
1021 depends on X86_32 && DISCONTIGMEM
1023 config NEED_NODE_MEMMAP_SIZE
1025 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1027 config HAVE_ARCH_ALLOC_REMAP
1029 depends on X86_32 && NUMA
1031 config ARCH_FLATMEM_ENABLE
1033 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1035 config ARCH_DISCONTIGMEM_ENABLE
1037 depends on NUMA && X86_32
1039 config ARCH_DISCONTIGMEM_DEFAULT
1041 depends on NUMA && X86_32
1043 config ARCH_SPARSEMEM_DEFAULT
1047 config ARCH_SPARSEMEM_ENABLE
1049 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1050 select SPARSEMEM_STATIC if X86_32
1051 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1053 config ARCH_SELECT_MEMORY_MODEL
1055 depends on ARCH_SPARSEMEM_ENABLE
1057 config ARCH_MEMORY_PROBE
1059 depends on MEMORY_HOTPLUG
1064 bool "Allocate 3rd-level pagetables from highmem"
1065 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1067 The VM uses one page table entry for each page of physical memory.
1068 For systems with a lot of RAM, this can be wasteful of precious
1069 low memory. Setting this option will put user-space page table
1070 entries in high memory.
1072 config X86_CHECK_BIOS_CORRUPTION
1073 bool "Check for low memory corruption"
1075 Periodically check for memory corruption in low memory, which
1076 is suspected to be caused by BIOS. Even when enabled in the
1077 configuration, it is disabled at runtime. Enable it by
1078 setting "memory_corruption_check=1" on the kernel command
1079 line. By default it scans the low 64k of memory every 60
1080 seconds; see the memory_corruption_check_size and
1081 memory_corruption_check_period parameters in
1082 Documentation/kernel-parameters.txt to adjust this.
1084 When enabled with the default parameters, this option has
1085 almost no overhead, as it reserves a relatively small amount
1086 of memory and scans it infrequently. It both detects corruption
1087 and prevents it from affecting the running system.
1089 It is, however, intended as a diagnostic tool; if repeatable
1090 BIOS-originated corruption always affects the same memory,
1091 you can use memmap= to prevent the kernel from using that
1094 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1095 bool "Set the default setting of memory_corruption_check"
1096 depends on X86_CHECK_BIOS_CORRUPTION
1099 Set whether the default state of memory_corruption_check is
1102 config X86_RESERVE_LOW_64K
1103 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1106 Reserve the first 64K of physical RAM on BIOSes that are known
1107 to potentially corrupt that memory range. A numbers of BIOSes are
1108 known to utilize this area during suspend/resume, so it must not
1109 be used by the kernel.
1111 Set this to N if you are absolutely sure that you trust the BIOS
1112 to get all its memory reservations and usages right.
1114 If you have doubts about the BIOS (e.g. suspend/resume does not
1115 work or there's kernel crashes after certain hardware hotplug
1116 events) and it's not AMI or Phoenix, then you might want to enable
1117 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1118 corruption patterns.
1122 config MATH_EMULATION
1124 prompt "Math emulation" if X86_32
1126 Linux can emulate a math coprocessor (used for floating point
1127 operations) if you don't have one. 486DX and Pentium processors have
1128 a math coprocessor built in, 486SX and 386 do not, unless you added
1129 a 487DX or 387, respectively. (The messages during boot time can
1130 give you some hints here ["man dmesg"].) Everyone needs either a
1131 coprocessor or this emulation.
1133 If you don't have a math coprocessor, you need to say Y here; if you
1134 say Y here even though you have a coprocessor, the coprocessor will
1135 be used nevertheless. (This behavior can be changed with the kernel
1136 command line option "no387", which comes handy if your coprocessor
1137 is broken. Try "man bootparam" or see the documentation of your boot
1138 loader (lilo or loadlin) about how to pass options to the kernel at
1139 boot time.) This means that it is a good idea to say Y here if you
1140 intend to use this kernel on different machines.
1142 More information about the internals of the Linux math coprocessor
1143 emulation can be found in <file:arch/x86/math-emu/README>.
1145 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1146 kernel, it won't hurt.
1149 bool "MTRR (Memory Type Range Register) support"
1151 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1152 the Memory Type Range Registers (MTRRs) may be used to control
1153 processor access to memory ranges. This is most useful if you have
1154 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1155 allows bus write transfers to be combined into a larger transfer
1156 before bursting over the PCI/AGP bus. This can increase performance
1157 of image write operations 2.5 times or more. Saying Y here creates a
1158 /proc/mtrr file which may be used to manipulate your processor's
1159 MTRRs. Typically the X server should use this.
1161 This code has a reasonably generic interface so that similar
1162 control registers on other processors can be easily supported
1165 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1166 Registers (ARRs) which provide a similar functionality to MTRRs. For
1167 these, the ARRs are used to emulate the MTRRs.
1168 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1169 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1170 write-combining. All of these processors are supported by this code
1171 and it makes sense to say Y here if you have one of them.
1173 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1174 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1175 can lead to all sorts of problems, so it's good to say Y here.
1177 You can safely say Y even if your machine doesn't have MTRRs, you'll
1178 just add about 9 KB to your kernel.
1180 See <file:Documentation/x86/mtrr.txt> for more information.
1182 config MTRR_SANITIZER
1184 prompt "MTRR cleanup support"
1187 Convert MTRR layout from continuous to discrete, so X drivers can
1188 add writeback entries.
1190 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1191 The largest mtrr entry size for a continous block can be set with
1196 config MTRR_SANITIZER_ENABLE_DEFAULT
1197 int "MTRR cleanup enable value (0-1)"
1200 depends on MTRR_SANITIZER
1202 Enable mtrr cleanup default value
1204 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1205 int "MTRR cleanup spare reg num (0-7)"
1208 depends on MTRR_SANITIZER
1210 mtrr cleanup spare entries default, it can be changed via
1211 mtrr_spare_reg_nr=N on the kernel command line.
1215 prompt "x86 PAT support"
1218 Use PAT attributes to setup page level cache control.
1220 PATs are the modern equivalents of MTRRs and are much more
1221 flexible than MTRRs.
1223 Say N here if you see bootup problems (boot crash, boot hang,
1224 spontaneous reboots) or a non-working video driver.
1229 bool "EFI runtime service support"
1232 This enables the kernel to use EFI runtime services that are
1233 available (such as the EFI variable services).
1235 This option is only useful on systems that have EFI firmware.
1236 In addition, you should use the latest ELILO loader available
1237 at <http://elilo.sourceforge.net> in order to take advantage
1238 of EFI runtime services. However, even with this option, the
1239 resultant kernel should continue to boot on existing non-EFI
1244 prompt "Enable kernel irq balancing"
1245 depends on X86_32 && SMP && X86_IO_APIC
1247 The default yes will allow the kernel to do irq load balancing.
1248 Saying no will keep the kernel from doing irq load balancing.
1252 prompt "Enable seccomp to safely compute untrusted bytecode"
1254 This kernel feature is useful for number crunching applications
1255 that may need to compute untrusted bytecode during their
1256 execution. By using pipes or other transports made available to
1257 the process as file descriptors supporting the read/write
1258 syscalls, it's possible to isolate those applications in
1259 their own address space using seccomp. Once seccomp is
1260 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1261 and the task is only allowed to execute a few safe syscalls
1262 defined by each seccomp mode.
1264 If unsure, say Y. Only embedded should say N here.
1266 config CC_STACKPROTECTOR
1267 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1268 depends on X86_64 && EXPERIMENTAL && BROKEN
1270 This option turns on the -fstack-protector GCC feature. This
1271 feature puts, at the beginning of critical functions, a canary
1272 value on the stack just before the return address, and validates
1273 the value just before actually returning. Stack based buffer
1274 overflows (that need to overwrite this return address) now also
1275 overwrite the canary, which gets detected and the attack is then
1276 neutralized via a kernel panic.
1278 This feature requires gcc version 4.2 or above, or a distribution
1279 gcc with the feature backported. Older versions are automatically
1280 detected and for those versions, this configuration option is ignored.
1282 config CC_STACKPROTECTOR_ALL
1283 bool "Use stack-protector for all functions"
1284 depends on CC_STACKPROTECTOR
1286 Normally, GCC only inserts the canary value protection for
1287 functions that use large-ish on-stack buffers. By enabling
1288 this option, GCC will be asked to do this for ALL functions.
1290 source kernel/Kconfig.hz
1293 bool "kexec system call"
1294 depends on X86_BIOS_REBOOT
1296 kexec is a system call that implements the ability to shutdown your
1297 current kernel, and to start another kernel. It is like a reboot
1298 but it is independent of the system firmware. And like a reboot
1299 you can start any kernel with it, not just Linux.
1301 The name comes from the similarity to the exec system call.
1303 It is an ongoing process to be certain the hardware in a machine
1304 is properly shutdown, so do not be surprised if this code does not
1305 initially work for you. It may help to enable device hotplugging
1306 support. As of this writing the exact hardware interface is
1307 strongly in flux, so no good recommendation can be made.
1310 bool "kernel crash dumps"
1311 depends on X86_64 || (X86_32 && HIGHMEM)
1313 Generate crash dump after being started by kexec.
1314 This should be normally only set in special crash dump kernels
1315 which are loaded in the main kernel with kexec-tools into
1316 a specially reserved region and then later executed after
1317 a crash by kdump/kexec. The crash dump kernel must be compiled
1318 to a memory address not used by the main kernel or BIOS using
1319 PHYSICAL_START, or it must be built as a relocatable image
1320 (CONFIG_RELOCATABLE=y).
1321 For more details see Documentation/kdump/kdump.txt
1324 bool "kexec jump (EXPERIMENTAL)"
1325 depends on EXPERIMENTAL
1326 depends on KEXEC && HIBERNATION && X86_32
1328 Jump between original kernel and kexeced kernel and invoke
1329 code in physical address mode via KEXEC
1331 config PHYSICAL_START
1332 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1333 default "0x1000000" if X86_NUMAQ
1334 default "0x200000" if X86_64
1337 This gives the physical address where the kernel is loaded.
1339 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1340 bzImage will decompress itself to above physical address and
1341 run from there. Otherwise, bzImage will run from the address where
1342 it has been loaded by the boot loader and will ignore above physical
1345 In normal kdump cases one does not have to set/change this option
1346 as now bzImage can be compiled as a completely relocatable image
1347 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1348 address. This option is mainly useful for the folks who don't want
1349 to use a bzImage for capturing the crash dump and want to use a
1350 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1351 to be specifically compiled to run from a specific memory area
1352 (normally a reserved region) and this option comes handy.
1354 So if you are using bzImage for capturing the crash dump, leave
1355 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1356 Otherwise if you plan to use vmlinux for capturing the crash dump
1357 change this value to start of the reserved region (Typically 16MB
1358 0x1000000). In other words, it can be set based on the "X" value as
1359 specified in the "crashkernel=YM@XM" command line boot parameter
1360 passed to the panic-ed kernel. Typically this parameter is set as
1361 crashkernel=64M@16M. Please take a look at
1362 Documentation/kdump/kdump.txt for more details about crash dumps.
1364 Usage of bzImage for capturing the crash dump is recommended as
1365 one does not have to build two kernels. Same kernel can be used
1366 as production kernel and capture kernel. Above option should have
1367 gone away after relocatable bzImage support is introduced. But it
1368 is present because there are users out there who continue to use
1369 vmlinux for dump capture. This option should go away down the
1372 Don't change this unless you know what you are doing.
1375 bool "Build a relocatable kernel (EXPERIMENTAL)"
1376 depends on EXPERIMENTAL
1378 This builds a kernel image that retains relocation information
1379 so it can be loaded someplace besides the default 1MB.
1380 The relocations tend to make the kernel binary about 10% larger,
1381 but are discarded at runtime.
1383 One use is for the kexec on panic case where the recovery kernel
1384 must live at a different physical address than the primary
1387 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1388 it has been loaded at and the compile time physical address
1389 (CONFIG_PHYSICAL_START) is ignored.
1391 config PHYSICAL_ALIGN
1393 prompt "Alignment value to which kernel should be aligned" if X86_32
1394 default "0x100000" if X86_32
1395 default "0x200000" if X86_64
1396 range 0x2000 0x400000
1398 This value puts the alignment restrictions on physical address
1399 where kernel is loaded and run from. Kernel is compiled for an
1400 address which meets above alignment restriction.
1402 If bootloader loads the kernel at a non-aligned address and
1403 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1404 address aligned to above value and run from there.
1406 If bootloader loads the kernel at a non-aligned address and
1407 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1408 load address and decompress itself to the address it has been
1409 compiled for and run from there. The address for which kernel is
1410 compiled already meets above alignment restrictions. Hence the
1411 end result is that kernel runs from a physical address meeting
1412 above alignment restrictions.
1414 Don't change this unless you know what you are doing.
1417 bool "Support for hot-pluggable CPUs"
1418 depends on SMP && HOTPLUG && !X86_VOYAGER
1420 Say Y here to allow turning CPUs off and on. CPUs can be
1421 controlled through /sys/devices/system/cpu.
1422 ( Note: power management support will enable this option
1423 automatically on SMP systems. )
1424 Say N if you want to disable CPU hotplug.
1428 prompt "Compat VDSO support"
1429 depends on X86_32 || IA32_EMULATION
1431 Map the 32-bit VDSO to the predictable old-style address too.
1433 Say N here if you are running a sufficiently recent glibc
1434 version (2.3.3 or later), to remove the high-mapped
1435 VDSO mapping and to exclusively use the randomized VDSO.
1440 bool "Built-in kernel command line"
1443 Allow for specifying boot arguments to the kernel at
1444 build time. On some systems (e.g. embedded ones), it is
1445 necessary or convenient to provide some or all of the
1446 kernel boot arguments with the kernel itself (that is,
1447 to not rely on the boot loader to provide them.)
1449 To compile command line arguments into the kernel,
1450 set this option to 'Y', then fill in the
1451 the boot arguments in CONFIG_CMDLINE.
1453 Systems with fully functional boot loaders (i.e. non-embedded)
1454 should leave this option set to 'N'.
1457 string "Built-in kernel command string"
1458 depends on CMDLINE_BOOL
1461 Enter arguments here that should be compiled into the kernel
1462 image and used at boot time. If the boot loader provides a
1463 command line at boot time, it is appended to this string to
1464 form the full kernel command line, when the system boots.
1466 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1467 change this behavior.
1469 In most cases, the command line (whether built-in or provided
1470 by the boot loader) should specify the device for the root
1473 config CMDLINE_OVERRIDE
1474 bool "Built-in command line overrides boot loader arguments"
1476 depends on CMDLINE_BOOL
1478 Set this option to 'Y' to have the kernel ignore the boot loader
1479 command line, and use ONLY the built-in command line.
1481 This is used to work around broken boot loaders. This should
1482 be set to 'N' under normal conditions.
1486 config ARCH_ENABLE_MEMORY_HOTPLUG
1488 depends on X86_64 || (X86_32 && HIGHMEM)
1490 config HAVE_ARCH_EARLY_PFN_TO_NID
1494 menu "Power management options"
1495 depends on !X86_VOYAGER
1497 config ARCH_HIBERNATION_HEADER
1499 depends on X86_64 && HIBERNATION
1501 source "kernel/power/Kconfig"
1503 source "drivers/acpi/Kconfig"
1508 depends on APM || APM_MODULE
1511 tristate "APM (Advanced Power Management) BIOS support"
1512 depends on X86_32 && PM_SLEEP
1514 APM is a BIOS specification for saving power using several different
1515 techniques. This is mostly useful for battery powered laptops with
1516 APM compliant BIOSes. If you say Y here, the system time will be
1517 reset after a RESUME operation, the /proc/apm device will provide
1518 battery status information, and user-space programs will receive
1519 notification of APM "events" (e.g. battery status change).
1521 If you select "Y" here, you can disable actual use of the APM
1522 BIOS by passing the "apm=off" option to the kernel at boot time.
1524 Note that the APM support is almost completely disabled for
1525 machines with more than one CPU.
1527 In order to use APM, you will need supporting software. For location
1528 and more information, read <file:Documentation/power/pm.txt> and the
1529 Battery Powered Linux mini-HOWTO, available from
1530 <http://www.tldp.org/docs.html#howto>.
1532 This driver does not spin down disk drives (see the hdparm(8)
1533 manpage ("man 8 hdparm") for that), and it doesn't turn off
1534 VESA-compliant "green" monitors.
1536 This driver does not support the TI 4000M TravelMate and the ACER
1537 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1538 desktop machines also don't have compliant BIOSes, and this driver
1539 may cause those machines to panic during the boot phase.
1541 Generally, if you don't have a battery in your machine, there isn't
1542 much point in using this driver and you should say N. If you get
1543 random kernel OOPSes or reboots that don't seem to be related to
1544 anything, try disabling/enabling this option (or disabling/enabling
1547 Some other things you should try when experiencing seemingly random,
1550 1) make sure that you have enough swap space and that it is
1552 2) pass the "no-hlt" option to the kernel
1553 3) switch on floating point emulation in the kernel and pass
1554 the "no387" option to the kernel
1555 4) pass the "floppy=nodma" option to the kernel
1556 5) pass the "mem=4M" option to the kernel (thereby disabling
1557 all but the first 4 MB of RAM)
1558 6) make sure that the CPU is not over clocked.
1559 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1560 8) disable the cache from your BIOS settings
1561 9) install a fan for the video card or exchange video RAM
1562 10) install a better fan for the CPU
1563 11) exchange RAM chips
1564 12) exchange the motherboard.
1566 To compile this driver as a module, choose M here: the
1567 module will be called apm.
1571 config APM_IGNORE_USER_SUSPEND
1572 bool "Ignore USER SUSPEND"
1574 This option will ignore USER SUSPEND requests. On machines with a
1575 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1576 series notebooks, it is necessary to say Y because of a BIOS bug.
1578 config APM_DO_ENABLE
1579 bool "Enable PM at boot time"
1581 Enable APM features at boot time. From page 36 of the APM BIOS
1582 specification: "When disabled, the APM BIOS does not automatically
1583 power manage devices, enter the Standby State, enter the Suspend
1584 State, or take power saving steps in response to CPU Idle calls."
1585 This driver will make CPU Idle calls when Linux is idle (unless this
1586 feature is turned off -- see "Do CPU IDLE calls", below). This
1587 should always save battery power, but more complicated APM features
1588 will be dependent on your BIOS implementation. You may need to turn
1589 this option off if your computer hangs at boot time when using APM
1590 support, or if it beeps continuously instead of suspending. Turn
1591 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1592 T400CDT. This is off by default since most machines do fine without
1596 bool "Make CPU Idle calls when idle"
1598 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1599 On some machines, this can activate improved power savings, such as
1600 a slowed CPU clock rate, when the machine is idle. These idle calls
1601 are made after the idle loop has run for some length of time (e.g.,
1602 333 mS). On some machines, this will cause a hang at boot time or
1603 whenever the CPU becomes idle. (On machines with more than one CPU,
1604 this option does nothing.)
1606 config APM_DISPLAY_BLANK
1607 bool "Enable console blanking using APM"
1609 Enable console blanking using the APM. Some laptops can use this to
1610 turn off the LCD backlight when the screen blanker of the Linux
1611 virtual console blanks the screen. Note that this is only used by
1612 the virtual console screen blanker, and won't turn off the backlight
1613 when using the X Window system. This also doesn't have anything to
1614 do with your VESA-compliant power-saving monitor. Further, this
1615 option doesn't work for all laptops -- it might not turn off your
1616 backlight at all, or it might print a lot of errors to the console,
1617 especially if you are using gpm.
1619 config APM_ALLOW_INTS
1620 bool "Allow interrupts during APM BIOS calls"
1622 Normally we disable external interrupts while we are making calls to
1623 the APM BIOS as a measure to lessen the effects of a badly behaving
1624 BIOS implementation. The BIOS should reenable interrupts if it
1625 needs to. Unfortunately, some BIOSes do not -- especially those in
1626 many of the newer IBM Thinkpads. If you experience hangs when you
1627 suspend, try setting this to Y. Otherwise, say N.
1629 config APM_REAL_MODE_POWER_OFF
1630 bool "Use real mode APM BIOS call to power off"
1632 Use real mode APM BIOS calls to switch off the computer. This is
1633 a work-around for a number of buggy BIOSes. Switch this option on if
1634 your computer crashes instead of powering off properly.
1638 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1640 source "drivers/cpuidle/Kconfig"
1645 menu "Bus options (PCI etc.)"
1650 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1652 Find out whether you have a PCI motherboard. PCI is the name of a
1653 bus system, i.e. the way the CPU talks to the other stuff inside
1654 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1655 VESA. If you have PCI, say Y, otherwise N.
1658 prompt "PCI access mode"
1659 depends on X86_32 && PCI
1662 On PCI systems, the BIOS can be used to detect the PCI devices and
1663 determine their configuration. However, some old PCI motherboards
1664 have BIOS bugs and may crash if this is done. Also, some embedded
1665 PCI-based systems don't have any BIOS at all. Linux can also try to
1666 detect the PCI hardware directly without using the BIOS.
1668 With this option, you can specify how Linux should detect the
1669 PCI devices. If you choose "BIOS", the BIOS will be used,
1670 if you choose "Direct", the BIOS won't be used, and if you
1671 choose "MMConfig", then PCI Express MMCONFIG will be used.
1672 If you choose "Any", the kernel will try MMCONFIG, then the
1673 direct access method and falls back to the BIOS if that doesn't
1674 work. If unsure, go with the default, which is "Any".
1679 config PCI_GOMMCONFIG
1696 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1698 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1701 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1705 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1709 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1716 bool "Support mmconfig PCI config space access"
1717 depends on X86_64 && PCI && ACPI
1720 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1721 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1723 DMA remapping (DMAR) devices support enables independent address
1724 translations for Direct Memory Access (DMA) from devices.
1725 These DMA remapping devices are reported via ACPI tables
1726 and include PCI device scope covered by these DMA
1731 prompt "Support for Graphics workaround"
1734 Current Graphics drivers tend to use physical address
1735 for DMA and avoid using DMA APIs. Setting this config
1736 option permits the IOMMU driver to set a unity map for
1737 all the OS-visible memory. Hence the driver can continue
1738 to use physical addresses for DMA.
1740 config DMAR_FLOPPY_WA
1744 Floppy disk drivers are know to bypass DMA API calls
1745 thereby failing to work when IOMMU is enabled. This
1746 workaround will setup a 1:1 mapping for the first
1747 16M to make floppy (an ISA device) work.
1750 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1751 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1753 Supports Interrupt remapping for IO-APIC and MSI devices.
1754 To use x2apic mode in the CPU's which support x2APIC enhancements or
1755 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1757 source "drivers/pci/pcie/Kconfig"
1759 source "drivers/pci/Kconfig"
1761 # x86_64 have no ISA slots, but do have ISA-style DMA.
1769 depends on !X86_VOYAGER
1771 Find out whether you have ISA slots on your motherboard. ISA is the
1772 name of a bus system, i.e. the way the CPU talks to the other stuff
1773 inside your box. Other bus systems are PCI, EISA, MicroChannel
1774 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1775 newer boards don't support it. If you have ISA, say Y, otherwise N.
1781 The Extended Industry Standard Architecture (EISA) bus was
1782 developed as an open alternative to the IBM MicroChannel bus.
1784 The EISA bus provided some of the features of the IBM MicroChannel
1785 bus while maintaining backward compatibility with cards made for
1786 the older ISA bus. The EISA bus saw limited use between 1988 and
1787 1995 when it was made obsolete by the PCI bus.
1789 Say Y here if you are building a kernel for an EISA-based machine.
1793 source "drivers/eisa/Kconfig"
1796 bool "MCA support" if !X86_VOYAGER
1797 default y if X86_VOYAGER
1799 MicroChannel Architecture is found in some IBM PS/2 machines and
1800 laptops. It is a bus system similar to PCI or ISA. See
1801 <file:Documentation/mca.txt> (and especially the web page given
1802 there) before attempting to build an MCA bus kernel.
1804 source "drivers/mca/Kconfig"
1807 tristate "NatSemi SCx200 support"
1808 depends on !X86_VOYAGER
1810 This provides basic support for National Semiconductor's
1811 (now AMD's) Geode processors. The driver probes for the
1812 PCI-IDs of several on-chip devices, so its a good dependency
1813 for other scx200_* drivers.
1815 If compiled as a module, the driver is named scx200.
1817 config SCx200HR_TIMER
1818 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1819 depends on SCx200 && GENERIC_TIME
1822 This driver provides a clocksource built upon the on-chip
1823 27MHz high-resolution timer. Its also a workaround for
1824 NSC Geode SC-1100's buggy TSC, which loses time when the
1825 processor goes idle (as is done by the scheduler). The
1826 other workaround is idle=poll boot option.
1828 config GEODE_MFGPT_TIMER
1830 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1831 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1833 This driver provides a clock event source based on the MFGPT
1834 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1835 MFGPTs have a better resolution and max interval than the
1836 generic PIT, and are suitable for use as high-res timers.
1839 bool "One Laptop Per Child support"
1842 Add support for detecting the unique features of the OLPC
1849 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1851 source "drivers/pcmcia/Kconfig"
1853 source "drivers/pci/hotplug/Kconfig"
1858 menu "Executable file formats / Emulations"
1860 source "fs/Kconfig.binfmt"
1862 config IA32_EMULATION
1863 bool "IA32 Emulation"
1865 select COMPAT_BINFMT_ELF
1867 Include code to run 32-bit programs under a 64-bit kernel. You should
1868 likely turn this on, unless you're 100% sure that you don't have any
1869 32-bit programs left.
1872 tristate "IA32 a.out support"
1873 depends on IA32_EMULATION
1875 Support old a.out binaries in the 32bit emulation.
1879 depends on IA32_EMULATION
1881 config COMPAT_FOR_U64_ALIGNMENT
1885 config SYSVIPC_COMPAT
1887 depends on COMPAT && SYSVIPC
1892 source "net/Kconfig"
1894 source "drivers/Kconfig"
1896 source "drivers/firmware/Kconfig"
1900 source "arch/x86/Kconfig.debug"
1902 source "security/Kconfig"
1904 source "crypto/Kconfig"
1906 source "arch/x86/kvm/Kconfig"
1908 source "lib/Kconfig"
projects / linux-2.6 / blob