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
37 select HAVE_SPARSE_IRQ if X86_64
41 default "arch/x86/configs/i386_defconfig" if X86_32
42 default "arch/x86/configs/x86_64_defconfig" if X86_64
45 config GENERIC_LOCKBREAK
51 config GENERIC_CMOS_UPDATE
54 config CLOCKSOURCE_WATCHDOG
57 config GENERIC_CLOCKEVENTS
60 config GENERIC_CLOCKEVENTS_BROADCAST
62 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
64 config LOCKDEP_SUPPORT
67 config STACKTRACE_SUPPORT
70 config HAVE_LATENCYTOP_SUPPORT
73 config FAST_CMPXCHG_LOCAL
86 config GENERIC_ISA_DMA
96 config GENERIC_HWEIGHT
102 config ARCH_MAY_HAVE_PC_FDC
105 config RWSEM_GENERIC_SPINLOCK
108 config RWSEM_XCHGADD_ALGORITHM
111 config ARCH_HAS_ILOG2_U32
114 config ARCH_HAS_ILOG2_U64
117 config ARCH_HAS_CPU_IDLE_WAIT
120 config GENERIC_CALIBRATE_DELAY
123 config GENERIC_TIME_VSYSCALL
127 config ARCH_HAS_CPU_RELAX
130 config ARCH_HAS_CACHE_LINE_SIZE
133 config HAVE_SETUP_PER_CPU_AREA
134 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
136 config HAVE_CPUMASK_OF_CPU_MAP
139 config ARCH_HIBERNATION_POSSIBLE
141 depends on !SMP || !X86_VOYAGER
143 config ARCH_SUSPEND_POSSIBLE
145 depends on !X86_VOYAGER
151 config ARCH_POPULATES_NODE_MAP
158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
161 # Use the generic interrupt handling code in kernel/irq/:
162 config GENERIC_HARDIRQS
166 config GENERIC_IRQ_PROBE
170 config GENERIC_PENDING_IRQ
172 depends on GENERIC_HARDIRQS && SMP
177 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
178 select USE_GENERIC_SMP_HELPERS
183 depends on X86_32 && SMP
187 depends on X86_64 && SMP
192 depends on (X86_32 && !X86_VOYAGER) || X86_64
195 config X86_BIOS_REBOOT
197 depends on !X86_VOYAGER
200 config X86_TRAMPOLINE
202 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
207 source "init/Kconfig"
209 menu "Processor type and features"
211 source "kernel/time/Kconfig"
214 bool "Symmetric multi-processing support"
216 This enables support for systems with more than one CPU. If you have
217 a system with only one CPU, like most personal computers, say N. If
218 you have a system with more than one CPU, say Y.
220 If you say N here, the kernel will run on single and multiprocessor
221 machines, but will use only one CPU of a multiprocessor machine. If
222 you say Y here, the kernel will run on many, but not all,
223 singleprocessor machines. On a singleprocessor machine, the kernel
224 will run faster if you say N here.
226 Note that if you say Y here and choose architecture "586" or
227 "Pentium" under "Processor family", the kernel will not work on 486
228 architectures. Similarly, multiprocessor kernels for the "PPro"
229 architecture may not work on all Pentium based boards.
231 People using multiprocessor machines who say Y here should also say
232 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
233 Management" code will be disabled if you say Y here.
235 See also <file:Documentation/i386/IO-APIC.txt>,
236 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
237 <http://www.tldp.org/docs.html#howto>.
239 If you don't know what to do here, say N.
241 config X86_FIND_SMP_CONFIG
243 depends on X86_MPPARSE || X86_VOYAGER
248 bool "Enable MPS table"
249 depends on X86_LOCAL_APIC
251 For old smp systems that do not have proper acpi support. Newer systems
252 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
258 depends on X86_LOCAL_APIC
262 prompt "Subarchitecture Type"
268 Choose this option if your computer is a standard PC or compatible.
274 Select this for an AMD Elan processor.
276 Do not use this option for K6/Athlon/Opteron processors!
278 If unsure, choose "PC-compatible" instead.
282 depends on X86_32 && (SMP || BROKEN) && !PCI
284 Voyager is an MCA-based 32-way capable SMP architecture proprietary
285 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
289 If you do not specifically know you have a Voyager based machine,
290 say N here, otherwise the kernel you build will not be bootable.
292 config X86_GENERICARCH
293 bool "Generic architecture"
296 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
297 subarchitectures. It is intended for a generic binary kernel.
298 if you select them all, kernel will probe it one by one. and will
304 bool "NUMAQ (IBM/Sequent)"
305 depends on SMP && X86_32 && PCI && X86_MPPARSE
308 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
309 NUMA multiquad box. This changes the way that processors are
310 bootstrapped, and uses Clustered Logical APIC addressing mode instead
311 of Flat Logical. You will need a new lynxer.elf file to flash your
312 firmware with - send email to <Martin.Bligh@us.ibm.com>.
315 bool "Summit/EXA (IBM x440)"
316 depends on X86_32 && SMP
318 This option is needed for IBM systems that use the Summit/EXA chipset.
319 In particular, it is needed for the x440.
322 bool "Support for Unisys ES7000 IA32 series"
323 depends on X86_32 && SMP
325 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
326 supposed to run on an IA32-based Unisys ES7000 system.
329 bool "Support for big SMP systems with more than 8 CPUs"
330 depends on X86_32 && SMP
332 This option is needed for the systems that have more than 8 CPUs
333 and if the system is not of any sub-arch type above.
338 bool "Support for ScaleMP vSMP"
340 depends on X86_64 && PCI
342 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
343 supposed to run on these EM64T-based machines. Only choose this option
344 if you have one of these machines.
349 bool "SGI 320/540 (Visual Workstation)"
350 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
352 The SGI Visual Workstation series is an IA32-based workstation
353 based on SGI systems chips with some legacy PC hardware attached.
355 Say Y here to create a kernel to run on the SGI 320 or 540.
357 A kernel compiled for the Visual Workstation will run on general
358 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
361 bool "RDC R-321x SoC"
364 select X86_REBOOTFIXUPS
366 This option is needed for RDC R-321x system-on-chip, also known
368 If you don't have one of these chips, you should say N here.
370 config SCHED_NO_NO_OMIT_FRAME_POINTER
372 prompt "Single-depth WCHAN output"
375 Calculate simpler /proc/<PID>/wchan values. If this option
376 is disabled then wchan values will recurse back to the
377 caller function. This provides more accurate wchan values,
378 at the expense of slightly more scheduling overhead.
380 If in doubt, say "Y".
382 menuconfig PARAVIRT_GUEST
383 bool "Paravirtualized guest support"
385 Say Y here to get to see options related to running Linux under
386 various hypervisors. This option alone does not add any kernel code.
388 If you say N, all options in this submenu will be skipped and disabled.
392 source "arch/x86/xen/Kconfig"
395 bool "VMI Guest support"
398 depends on !X86_VOYAGER
400 VMI provides a paravirtualized interface to the VMware ESX server
401 (it could be used by other hypervisors in theory too, but is not
402 at the moment), by linking the kernel to a GPL-ed ROM module
403 provided by the hypervisor.
406 bool "KVM paravirtualized clock"
408 select PARAVIRT_CLOCK
409 depends on !X86_VOYAGER
411 Turning on this option will allow you to run a paravirtualized clock
412 when running over the KVM hypervisor. Instead of relying on a PIT
413 (or probably other) emulation by the underlying device model, the host
414 provides the guest with timing infrastructure such as time of day, and
418 bool "KVM Guest support"
420 depends on !X86_VOYAGER
422 This option enables various optimizations for running under the KVM
425 source "arch/x86/lguest/Kconfig"
428 bool "Enable paravirtualization code"
429 depends on !X86_VOYAGER
431 This changes the kernel so it can modify itself when it is run
432 under a hypervisor, potentially improving performance significantly
433 over full virtualization. However, when run without a hypervisor
434 the kernel is theoretically slower and slightly larger.
436 config PARAVIRT_CLOCK
442 config PARAVIRT_DEBUG
443 bool "paravirt-ops debugging"
444 depends on PARAVIRT && DEBUG_KERNEL
446 Enable to debug paravirt_ops internals. Specifically, BUG if
447 a paravirt_op is missing when it is called.
452 This option adds a kernel parameter 'memtest', which allows memtest
454 memtest=0, mean disabled; -- default
455 memtest=1, mean do 1 test pattern;
457 memtest=4, mean do 4 test patterns.
458 If you are unsure how to answer this question, answer N.
460 config X86_SUMMIT_NUMA
462 depends on X86_32 && NUMA && X86_GENERICARCH
464 config X86_CYCLONE_TIMER
466 depends on X86_GENERICARCH
468 config ES7000_CLUSTERED_APIC
470 depends on SMP && X86_ES7000 && MPENTIUMIII
472 source "arch/x86/Kconfig.cpu"
476 prompt "HPET Timer Support" if X86_32
478 Use the IA-PC HPET (High Precision Event Timer) to manage
479 time in preference to the PIT and RTC, if a HPET is
481 HPET is the next generation timer replacing legacy 8254s.
482 The HPET provides a stable time base on SMP
483 systems, unlike the TSC, but it is more expensive to access,
484 as it is off-chip. You can find the HPET spec at
485 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
487 You can safely choose Y here. However, HPET will only be
488 activated if the platform and the BIOS support this feature.
489 Otherwise the 8254 will be used for timing services.
491 Choose N to continue using the legacy 8254 timer.
493 config HPET_EMULATE_RTC
495 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
497 # Mark as embedded because too many people got it wrong.
498 # The code disables itself when not needed.
501 bool "Enable DMI scanning" if EMBEDDED
503 Enabled scanning of DMI to identify machine quirks. Say Y
504 here unless you have verified that your setup is not
505 affected by entries in the DMI blacklist. Required by PNP
509 bool "GART IOMMU support" if EMBEDDED
513 depends on X86_64 && PCI
515 Support for full DMA access of devices with 32bit memory access only
516 on systems with more than 3GB. This is usually needed for USB,
517 sound, many IDE/SATA chipsets and some other devices.
518 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
519 based hardware IOMMU and a software bounce buffer based IOMMU used
520 on Intel systems and as fallback.
521 The code is only active when needed (enough memory and limited
522 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
526 bool "IBM Calgary IOMMU support"
528 depends on X86_64 && PCI && EXPERIMENTAL
530 Support for hardware IOMMUs in IBM's xSeries x366 and x460
531 systems. Needed to run systems with more than 3GB of memory
532 properly with 32-bit PCI devices that do not support DAC
533 (Double Address Cycle). Calgary also supports bus level
534 isolation, where all DMAs pass through the IOMMU. This
535 prevents them from going anywhere except their intended
536 destination. This catches hard-to-find kernel bugs and
537 mis-behaving drivers and devices that do not use the DMA-API
538 properly to set up their DMA buffers. The IOMMU can be
539 turned off at boot time with the iommu=off parameter.
540 Normally the kernel will make the right choice by itself.
543 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
545 prompt "Should Calgary be enabled by default?"
546 depends on CALGARY_IOMMU
548 Should Calgary be enabled by default? if you choose 'y', Calgary
549 will be used (if it exists). If you choose 'n', Calgary will not be
550 used even if it exists. If you choose 'n' and would like to use
551 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
555 bool "AMD IOMMU support"
558 depends on X86_64 && PCI && ACPI
560 With this option you can enable support for AMD IOMMU hardware in
561 your system. An IOMMU is a hardware component which provides
562 remapping of DMA memory accesses from devices. With an AMD IOMMU you
563 can isolate the the DMA memory of different devices and protect the
564 system from misbehaving device drivers or hardware.
566 You can find out if your system has an AMD IOMMU if you look into
567 your BIOS for an option to enable it or if you have an IVRS ACPI
570 # need this always selected by IOMMU for the VIA workaround
574 Support for software bounce buffers used on x86-64 systems
575 which don't have a hardware IOMMU (e.g. the current generation
576 of Intel's x86-64 CPUs). Using this PCI devices which can only
577 access 32-bits of memory can be used on systems with more than
578 3 GB of memory. If unsure, say Y.
581 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
584 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
585 depends on X86_64 && SMP && BROKEN
588 Configure maximum number of CPUS and NUMA Nodes for this architecture.
592 int "Maximum number of CPUs (2-512)" if !MAXSMP
595 default "4096" if MAXSMP
596 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
599 This allows you to specify the maximum number of CPUs which this
600 kernel will support. The maximum supported value is 512 and the
601 minimum value which makes sense is 2.
603 This is purely to save memory - each supported CPU adds
604 approximately eight kilobytes to the kernel image.
607 bool "SMT (Hyperthreading) scheduler support"
610 SMT scheduler support improves the CPU scheduler's decision making
611 when dealing with Intel Pentium 4 chips with HyperThreading at a
612 cost of slightly increased overhead in some places. If unsure say
617 prompt "Multi-core scheduler support"
620 Multi-core scheduler support improves the CPU scheduler's decision
621 making when dealing with multi-core CPU chips at a cost of slightly
622 increased overhead in some places. If unsure say N here.
624 source "kernel/Kconfig.preempt"
627 bool "Local APIC support on uniprocessors"
628 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
630 A local APIC (Advanced Programmable Interrupt Controller) is an
631 integrated interrupt controller in the CPU. If you have a single-CPU
632 system which has a processor with a local APIC, you can say Y here to
633 enable and use it. If you say Y here even though your machine doesn't
634 have a local APIC, then the kernel will still run with no slowdown at
635 all. The local APIC supports CPU-generated self-interrupts (timer,
636 performance counters), and the NMI watchdog which detects hard
640 bool "IO-APIC support on uniprocessors"
641 depends on X86_UP_APIC
643 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
644 SMP-capable replacement for PC-style interrupt controllers. Most
645 SMP systems and many recent uniprocessor systems have one.
647 If you have a single-CPU system with an IO-APIC, you can say Y here
648 to use it. If you say Y here even though your machine doesn't have
649 an IO-APIC, then the kernel will still run with no slowdown at all.
651 config X86_LOCAL_APIC
653 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
657 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
659 config X86_VISWS_APIC
661 depends on X86_32 && X86_VISWS
664 bool "Machine Check Exception"
665 depends on !X86_VOYAGER
667 Machine Check Exception support allows the processor to notify the
668 kernel if it detects a problem (e.g. overheating, component failure).
669 The action the kernel takes depends on the severity of the problem,
670 ranging from a warning message on the console, to halting the machine.
671 Your processor must be a Pentium or newer to support this - check the
672 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
673 have a design flaw which leads to false MCE events - hence MCE is
674 disabled on all P5 processors, unless explicitly enabled with "mce"
675 as a boot argument. Similarly, if MCE is built in and creates a
676 problem on some new non-standard machine, you can boot with "nomce"
677 to disable it. MCE support simply ignores non-MCE processors like
678 the 386 and 486, so nearly everyone can say Y here.
682 prompt "Intel MCE features"
683 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
685 Additional support for intel specific MCE features such as
690 prompt "AMD MCE features"
691 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
693 Additional support for AMD specific MCE features such as
694 the DRAM Error Threshold.
696 config X86_MCE_NONFATAL
697 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
698 depends on X86_32 && X86_MCE
700 Enabling this feature starts a timer that triggers every 5 seconds which
701 will look at the machine check registers to see if anything happened.
702 Non-fatal problems automatically get corrected (but still logged).
703 Disable this if you don't want to see these messages.
704 Seeing the messages this option prints out may be indicative of dying
705 or out-of-spec (ie, overclocked) hardware.
706 This option only does something on certain CPUs.
707 (AMD Athlon/Duron and Intel Pentium 4)
709 config X86_MCE_P4THERMAL
710 bool "check for P4 thermal throttling interrupt."
711 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
713 Enabling this feature will cause a message to be printed when the P4
714 enters thermal throttling.
717 bool "Enable VM86 support" if EMBEDDED
721 This option is required by programs like DOSEMU to run 16-bit legacy
722 code on X86 processors. It also may be needed by software like
723 XFree86 to initialize some video cards via BIOS. Disabling this
724 option saves about 6k.
727 tristate "Toshiba Laptop support"
730 This adds a driver to safely access the System Management Mode of
731 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
732 not work on models with a Phoenix BIOS. The System Management Mode
733 is used to set the BIOS and power saving options on Toshiba portables.
735 For information on utilities to make use of this driver see the
736 Toshiba Linux utilities web site at:
737 <http://www.buzzard.org.uk/toshiba/>.
739 Say Y if you intend to run this kernel on a Toshiba portable.
743 tristate "Dell laptop support"
745 This adds a driver to safely access the System Management Mode
746 of the CPU on the Dell Inspiron 8000. The System Management Mode
747 is used to read cpu temperature and cooling fan status and to
748 control the fans on the I8K portables.
750 This driver has been tested only on the Inspiron 8000 but it may
751 also work with other Dell laptops. You can force loading on other
752 models by passing the parameter `force=1' to the module. Use at
755 For information on utilities to make use of this driver see the
756 I8K Linux utilities web site at:
757 <http://people.debian.org/~dz/i8k/>
759 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
762 config X86_REBOOTFIXUPS
764 prompt "Enable X86 board specific fixups for reboot"
765 depends on X86_32 && X86
767 This enables chipset and/or board specific fixups to be done
768 in order to get reboot to work correctly. This is only needed on
769 some combinations of hardware and BIOS. The symptom, for which
770 this config is intended, is when reboot ends with a stalled/hung
773 Currently, the only fixup is for the Geode machines using
774 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
776 Say Y if you want to enable the fixup. Currently, it's safe to
777 enable this option even if you don't need it.
781 tristate "/dev/cpu/microcode - microcode support"
784 If you say Y here, you will be able to update the microcode on
785 certain Intel and AMD processors. The Intel support is for the
786 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
787 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
788 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
789 You will obviously need the actual microcode binary data itself
790 which is not shipped with the Linux kernel.
792 This option selects the general module only, you need to select
793 at least one vendor specific module as well.
795 To compile this driver as a module, choose M here: the
796 module will be called microcode.
798 config MICROCODE_INTEL
799 bool "Intel microcode patch loading support"
804 This options enables microcode patch loading support for Intel
807 For latest news and information on obtaining all the required
808 Intel ingredients for this driver, check:
809 <http://www.urbanmyth.org/microcode/>.
812 bool "AMD microcode patch loading support"
816 If you select this option, microcode patch loading support for AMD
817 processors will be enabled.
819 config MICROCODE_OLD_INTERFACE
824 tristate "/dev/cpu/*/msr - Model-specific register support"
826 This device gives privileged processes access to the x86
827 Model-Specific Registers (MSRs). It is a character device with
828 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
829 MSR accesses are directed to a specific CPU on multi-processor
833 tristate "/dev/cpu/*/cpuid - CPU information support"
835 This device gives processes access to the x86 CPUID instruction to
836 be executed on a specific processor. It is a character device
837 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
841 prompt "High Memory Support"
842 default HIGHMEM4G if !X86_NUMAQ
843 default HIGHMEM64G if X86_NUMAQ
848 depends on !X86_NUMAQ
850 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
851 However, the address space of 32-bit x86 processors is only 4
852 Gigabytes large. That means that, if you have a large amount of
853 physical memory, not all of it can be "permanently mapped" by the
854 kernel. The physical memory that's not permanently mapped is called
857 If you are compiling a kernel which will never run on a machine with
858 more than 1 Gigabyte total physical RAM, answer "off" here (default
859 choice and suitable for most users). This will result in a "3GB/1GB"
860 split: 3GB are mapped so that each process sees a 3GB virtual memory
861 space and the remaining part of the 4GB virtual memory space is used
862 by the kernel to permanently map as much physical memory as
865 If the machine has between 1 and 4 Gigabytes physical RAM, then
868 If more than 4 Gigabytes is used then answer "64GB" here. This
869 selection turns Intel PAE (Physical Address Extension) mode on.
870 PAE implements 3-level paging on IA32 processors. PAE is fully
871 supported by Linux, PAE mode is implemented on all recent Intel
872 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
873 then the kernel will not boot on CPUs that don't support PAE!
875 The actual amount of total physical memory will either be
876 auto detected or can be forced by using a kernel command line option
877 such as "mem=256M". (Try "man bootparam" or see the documentation of
878 your boot loader (lilo or loadlin) about how to pass options to the
879 kernel at boot time.)
881 If unsure, say "off".
885 depends on !X86_NUMAQ
887 Select this if you have a 32-bit processor and between 1 and 4
888 gigabytes of physical RAM.
892 depends on !M386 && !M486
895 Select this if you have a 32-bit processor and more than 4
896 gigabytes of physical RAM.
901 depends on EXPERIMENTAL
902 prompt "Memory split" if EMBEDDED
906 Select the desired split between kernel and user memory.
908 If the address range available to the kernel is less than the
909 physical memory installed, the remaining memory will be available
910 as "high memory". Accessing high memory is a little more costly
911 than low memory, as it needs to be mapped into the kernel first.
912 Note that increasing the kernel address space limits the range
913 available to user programs, making the address space there
914 tighter. Selecting anything other than the default 3G/1G split
915 will also likely make your kernel incompatible with binary-only
918 If you are not absolutely sure what you are doing, leave this
922 bool "3G/1G user/kernel split"
923 config VMSPLIT_3G_OPT
925 bool "3G/1G user/kernel split (for full 1G low memory)"
927 bool "2G/2G user/kernel split"
928 config VMSPLIT_2G_OPT
930 bool "2G/2G user/kernel split (for full 2G low memory)"
932 bool "1G/3G user/kernel split"
937 default 0xB0000000 if VMSPLIT_3G_OPT
938 default 0x80000000 if VMSPLIT_2G
939 default 0x78000000 if VMSPLIT_2G_OPT
940 default 0x40000000 if VMSPLIT_1G
946 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
950 prompt "PAE (Physical Address Extension) Support"
951 depends on X86_32 && !HIGHMEM4G
952 select RESOURCES_64BIT
954 PAE is required for NX support, and furthermore enables
955 larger swapspace support for non-overcommit purposes. It
956 has the cost of more pagetable lookup overhead, and also
957 consumes more pagetable space per process.
959 # Common NUMA Features
961 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
963 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
965 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
967 Enable NUMA (Non Uniform Memory Access) support.
968 The kernel will try to allocate memory used by a CPU on the
969 local memory controller of the CPU and add some more
970 NUMA awareness to the kernel.
972 For 32-bit this is currently highly experimental and should be only
973 used for kernel development. It might also cause boot failures.
974 For 64-bit this is recommended on all multiprocessor Opteron systems.
975 If the system is EM64T, you should say N unless your system is
978 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
979 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
983 prompt "Old style AMD Opteron NUMA detection"
984 depends on X86_64 && NUMA && PCI
986 Enable K8 NUMA node topology detection. You should say Y here if
987 you have a multi processor AMD K8 system. This uses an old
988 method to read the NUMA configuration directly from the builtin
989 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
990 instead, which also takes priority if both are compiled in.
992 config X86_64_ACPI_NUMA
994 prompt "ACPI NUMA detection"
995 depends on X86_64 && NUMA && ACPI && PCI
998 Enable ACPI SRAT based node topology detection.
1000 # Some NUMA nodes have memory ranges that span
1001 # other nodes. Even though a pfn is valid and
1002 # between a node's start and end pfns, it may not
1003 # reside on that node. See memmap_init_zone()
1005 config NODES_SPAN_OTHER_NODES
1007 depends on X86_64_ACPI_NUMA
1010 bool "NUMA emulation"
1011 depends on X86_64 && NUMA
1013 Enable NUMA emulation. A flat machine will be split
1014 into virtual nodes when booted with "numa=fake=N", where N is the
1015 number of nodes. This is only useful for debugging.
1018 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1020 default "9" if MAXSMP
1021 default "6" if X86_64
1022 default "4" if X86_NUMAQ
1024 depends on NEED_MULTIPLE_NODES
1026 Specify the maximum number of NUMA Nodes available on the target
1027 system. Increases memory reserved to accomodate various tables.
1029 config HAVE_ARCH_BOOTMEM_NODE
1031 depends on X86_32 && NUMA
1033 config ARCH_HAVE_MEMORY_PRESENT
1035 depends on X86_32 && DISCONTIGMEM
1037 config NEED_NODE_MEMMAP_SIZE
1039 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1041 config HAVE_ARCH_ALLOC_REMAP
1043 depends on X86_32 && NUMA
1045 config ARCH_FLATMEM_ENABLE
1047 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1049 config ARCH_DISCONTIGMEM_ENABLE
1051 depends on NUMA && X86_32
1053 config ARCH_DISCONTIGMEM_DEFAULT
1055 depends on NUMA && X86_32
1057 config ARCH_SPARSEMEM_DEFAULT
1061 config ARCH_SPARSEMEM_ENABLE
1063 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1064 select SPARSEMEM_STATIC if X86_32
1065 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1067 config ARCH_SELECT_MEMORY_MODEL
1069 depends on ARCH_SPARSEMEM_ENABLE
1071 config ARCH_MEMORY_PROBE
1073 depends on MEMORY_HOTPLUG
1078 bool "Allocate 3rd-level pagetables from highmem"
1079 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1081 The VM uses one page table entry for each page of physical memory.
1082 For systems with a lot of RAM, this can be wasteful of precious
1083 low memory. Setting this option will put user-space page table
1084 entries in high memory.
1086 config X86_CHECK_BIOS_CORRUPTION
1087 bool "Check for low memory corruption"
1089 Periodically check for memory corruption in low memory, which
1090 is suspected to be caused by BIOS. Even when enabled in the
1091 configuration, it is disabled at runtime. Enable it by
1092 setting "memory_corruption_check=1" on the kernel command
1093 line. By default it scans the low 64k of memory every 60
1094 seconds; see the memory_corruption_check_size and
1095 memory_corruption_check_period parameters in
1096 Documentation/kernel-parameters.txt to adjust this.
1098 When enabled with the default parameters, this option has
1099 almost no overhead, as it reserves a relatively small amount
1100 of memory and scans it infrequently. It both detects corruption
1101 and prevents it from affecting the running system.
1103 It is, however, intended as a diagnostic tool; if repeatable
1104 BIOS-originated corruption always affects the same memory,
1105 you can use memmap= to prevent the kernel from using that
1108 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1109 bool "Set the default setting of memory_corruption_check"
1110 depends on X86_CHECK_BIOS_CORRUPTION
1113 Set whether the default state of memory_corruption_check is
1116 config X86_RESERVE_LOW_64K
1117 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1120 Reserve the first 64K of physical RAM on BIOSes that are known
1121 to potentially corrupt that memory range. A numbers of BIOSes are
1122 known to utilize this area during suspend/resume, so it must not
1123 be used by the kernel.
1125 Set this to N if you are absolutely sure that you trust the BIOS
1126 to get all its memory reservations and usages right.
1128 If you have doubts about the BIOS (e.g. suspend/resume does not
1129 work or there's kernel crashes after certain hardware hotplug
1130 events) and it's not AMI or Phoenix, then you might want to enable
1131 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1132 corruption patterns.
1136 config MATH_EMULATION
1138 prompt "Math emulation" if X86_32
1140 Linux can emulate a math coprocessor (used for floating point
1141 operations) if you don't have one. 486DX and Pentium processors have
1142 a math coprocessor built in, 486SX and 386 do not, unless you added
1143 a 487DX or 387, respectively. (The messages during boot time can
1144 give you some hints here ["man dmesg"].) Everyone needs either a
1145 coprocessor or this emulation.
1147 If you don't have a math coprocessor, you need to say Y here; if you
1148 say Y here even though you have a coprocessor, the coprocessor will
1149 be used nevertheless. (This behavior can be changed with the kernel
1150 command line option "no387", which comes handy if your coprocessor
1151 is broken. Try "man bootparam" or see the documentation of your boot
1152 loader (lilo or loadlin) about how to pass options to the kernel at
1153 boot time.) This means that it is a good idea to say Y here if you
1154 intend to use this kernel on different machines.
1156 More information about the internals of the Linux math coprocessor
1157 emulation can be found in <file:arch/x86/math-emu/README>.
1159 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1160 kernel, it won't hurt.
1163 bool "MTRR (Memory Type Range Register) support"
1165 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1166 the Memory Type Range Registers (MTRRs) may be used to control
1167 processor access to memory ranges. This is most useful if you have
1168 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1169 allows bus write transfers to be combined into a larger transfer
1170 before bursting over the PCI/AGP bus. This can increase performance
1171 of image write operations 2.5 times or more. Saying Y here creates a
1172 /proc/mtrr file which may be used to manipulate your processor's
1173 MTRRs. Typically the X server should use this.
1175 This code has a reasonably generic interface so that similar
1176 control registers on other processors can be easily supported
1179 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1180 Registers (ARRs) which provide a similar functionality to MTRRs. For
1181 these, the ARRs are used to emulate the MTRRs.
1182 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1183 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1184 write-combining. All of these processors are supported by this code
1185 and it makes sense to say Y here if you have one of them.
1187 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1188 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1189 can lead to all sorts of problems, so it's good to say Y here.
1191 You can safely say Y even if your machine doesn't have MTRRs, you'll
1192 just add about 9 KB to your kernel.
1194 See <file:Documentation/x86/mtrr.txt> for more information.
1196 config MTRR_SANITIZER
1198 prompt "MTRR cleanup support"
1201 Convert MTRR layout from continuous to discrete, so X drivers can
1202 add writeback entries.
1204 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1205 The largest mtrr entry size for a continous block can be set with
1210 config MTRR_SANITIZER_ENABLE_DEFAULT
1211 int "MTRR cleanup enable value (0-1)"
1214 depends on MTRR_SANITIZER
1216 Enable mtrr cleanup default value
1218 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1219 int "MTRR cleanup spare reg num (0-7)"
1222 depends on MTRR_SANITIZER
1224 mtrr cleanup spare entries default, it can be changed via
1225 mtrr_spare_reg_nr=N on the kernel command line.
1229 prompt "x86 PAT support"
1232 Use PAT attributes to setup page level cache control.
1234 PATs are the modern equivalents of MTRRs and are much more
1235 flexible than MTRRs.
1237 Say N here if you see bootup problems (boot crash, boot hang,
1238 spontaneous reboots) or a non-working video driver.
1244 prompt "EFI runtime service support"
1247 This enables the kernel to use EFI runtime services that are
1248 available (such as the EFI variable services).
1250 This option is only useful on systems that have EFI firmware.
1251 In addition, you should use the latest ELILO loader available
1252 at <http://elilo.sourceforge.net> in order to take advantage
1253 of EFI runtime services. However, even with this option, the
1254 resultant kernel should continue to boot on existing non-EFI
1259 prompt "Enable seccomp to safely compute untrusted bytecode"
1261 This kernel feature is useful for number crunching applications
1262 that may need to compute untrusted bytecode during their
1263 execution. By using pipes or other transports made available to
1264 the process as file descriptors supporting the read/write
1265 syscalls, it's possible to isolate those applications in
1266 their own address space using seccomp. Once seccomp is
1267 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1268 and the task is only allowed to execute a few safe syscalls
1269 defined by each seccomp mode.
1271 If unsure, say Y. Only embedded should say N here.
1273 config CC_STACKPROTECTOR
1274 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1275 depends on X86_64 && EXPERIMENTAL && BROKEN
1277 This option turns on the -fstack-protector GCC feature. This
1278 feature puts, at the beginning of critical functions, a canary
1279 value on the stack just before the return address, and validates
1280 the value just before actually returning. Stack based buffer
1281 overflows (that need to overwrite this return address) now also
1282 overwrite the canary, which gets detected and the attack is then
1283 neutralized via a kernel panic.
1285 This feature requires gcc version 4.2 or above, or a distribution
1286 gcc with the feature backported. Older versions are automatically
1287 detected and for those versions, this configuration option is ignored.
1289 config CC_STACKPROTECTOR_ALL
1290 bool "Use stack-protector for all functions"
1291 depends on CC_STACKPROTECTOR
1293 Normally, GCC only inserts the canary value protection for
1294 functions that use large-ish on-stack buffers. By enabling
1295 this option, GCC will be asked to do this for ALL functions.
1297 source kernel/Kconfig.hz
1300 bool "kexec system call"
1301 depends on X86_BIOS_REBOOT
1303 kexec is a system call that implements the ability to shutdown your
1304 current kernel, and to start another kernel. It is like a reboot
1305 but it is independent of the system firmware. And like a reboot
1306 you can start any kernel with it, not just Linux.
1308 The name comes from the similarity to the exec system call.
1310 It is an ongoing process to be certain the hardware in a machine
1311 is properly shutdown, so do not be surprised if this code does not
1312 initially work for you. It may help to enable device hotplugging
1313 support. As of this writing the exact hardware interface is
1314 strongly in flux, so no good recommendation can be made.
1317 bool "kernel crash dumps"
1318 depends on X86_64 || (X86_32 && HIGHMEM)
1320 Generate crash dump after being started by kexec.
1321 This should be normally only set in special crash dump kernels
1322 which are loaded in the main kernel with kexec-tools into
1323 a specially reserved region and then later executed after
1324 a crash by kdump/kexec. The crash dump kernel must be compiled
1325 to a memory address not used by the main kernel or BIOS using
1326 PHYSICAL_START, or it must be built as a relocatable image
1327 (CONFIG_RELOCATABLE=y).
1328 For more details see Documentation/kdump/kdump.txt
1331 bool "kexec jump (EXPERIMENTAL)"
1332 depends on EXPERIMENTAL
1333 depends on KEXEC && HIBERNATION && X86_32
1335 Jump between original kernel and kexeced kernel and invoke
1336 code in physical address mode via KEXEC
1338 config PHYSICAL_START
1339 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1340 default "0x1000000" if X86_NUMAQ
1341 default "0x200000" if X86_64
1344 This gives the physical address where the kernel is loaded.
1346 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1347 bzImage will decompress itself to above physical address and
1348 run from there. Otherwise, bzImage will run from the address where
1349 it has been loaded by the boot loader and will ignore above physical
1352 In normal kdump cases one does not have to set/change this option
1353 as now bzImage can be compiled as a completely relocatable image
1354 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1355 address. This option is mainly useful for the folks who don't want
1356 to use a bzImage for capturing the crash dump and want to use a
1357 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1358 to be specifically compiled to run from a specific memory area
1359 (normally a reserved region) and this option comes handy.
1361 So if you are using bzImage for capturing the crash dump, leave
1362 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1363 Otherwise if you plan to use vmlinux for capturing the crash dump
1364 change this value to start of the reserved region (Typically 16MB
1365 0x1000000). In other words, it can be set based on the "X" value as
1366 specified in the "crashkernel=YM@XM" command line boot parameter
1367 passed to the panic-ed kernel. Typically this parameter is set as
1368 crashkernel=64M@16M. Please take a look at
1369 Documentation/kdump/kdump.txt for more details about crash dumps.
1371 Usage of bzImage for capturing the crash dump is recommended as
1372 one does not have to build two kernels. Same kernel can be used
1373 as production kernel and capture kernel. Above option should have
1374 gone away after relocatable bzImage support is introduced. But it
1375 is present because there are users out there who continue to use
1376 vmlinux for dump capture. This option should go away down the
1379 Don't change this unless you know what you are doing.
1382 bool "Build a relocatable kernel (EXPERIMENTAL)"
1383 depends on EXPERIMENTAL
1385 This builds a kernel image that retains relocation information
1386 so it can be loaded someplace besides the default 1MB.
1387 The relocations tend to make the kernel binary about 10% larger,
1388 but are discarded at runtime.
1390 One use is for the kexec on panic case where the recovery kernel
1391 must live at a different physical address than the primary
1394 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1395 it has been loaded at and the compile time physical address
1396 (CONFIG_PHYSICAL_START) is ignored.
1398 config PHYSICAL_ALIGN
1400 prompt "Alignment value to which kernel should be aligned" if X86_32
1401 default "0x100000" if X86_32
1402 default "0x200000" if X86_64
1403 range 0x2000 0x400000
1405 This value puts the alignment restrictions on physical address
1406 where kernel is loaded and run from. Kernel is compiled for an
1407 address which meets above alignment restriction.
1409 If bootloader loads the kernel at a non-aligned address and
1410 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1411 address aligned to above value and run from there.
1413 If bootloader loads the kernel at a non-aligned address and
1414 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1415 load address and decompress itself to the address it has been
1416 compiled for and run from there. The address for which kernel is
1417 compiled already meets above alignment restrictions. Hence the
1418 end result is that kernel runs from a physical address meeting
1419 above alignment restrictions.
1421 Don't change this unless you know what you are doing.
1424 bool "Support for hot-pluggable CPUs"
1425 depends on SMP && HOTPLUG && !X86_VOYAGER
1427 Say Y here to allow turning CPUs off and on. CPUs can be
1428 controlled through /sys/devices/system/cpu.
1429 ( Note: power management support will enable this option
1430 automatically on SMP systems. )
1431 Say N if you want to disable CPU hotplug.
1435 prompt "Compat VDSO support"
1436 depends on X86_32 || IA32_EMULATION
1438 Map the 32-bit VDSO to the predictable old-style address too.
1440 Say N here if you are running a sufficiently recent glibc
1441 version (2.3.3 or later), to remove the high-mapped
1442 VDSO mapping and to exclusively use the randomized VDSO.
1447 bool "Built-in kernel command line"
1450 Allow for specifying boot arguments to the kernel at
1451 build time. On some systems (e.g. embedded ones), it is
1452 necessary or convenient to provide some or all of the
1453 kernel boot arguments with the kernel itself (that is,
1454 to not rely on the boot loader to provide them.)
1456 To compile command line arguments into the kernel,
1457 set this option to 'Y', then fill in the
1458 the boot arguments in CONFIG_CMDLINE.
1460 Systems with fully functional boot loaders (i.e. non-embedded)
1461 should leave this option set to 'N'.
1464 string "Built-in kernel command string"
1465 depends on CMDLINE_BOOL
1468 Enter arguments here that should be compiled into the kernel
1469 image and used at boot time. If the boot loader provides a
1470 command line at boot time, it is appended to this string to
1471 form the full kernel command line, when the system boots.
1473 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1474 change this behavior.
1476 In most cases, the command line (whether built-in or provided
1477 by the boot loader) should specify the device for the root
1480 config CMDLINE_OVERRIDE
1481 bool "Built-in command line overrides boot loader arguments"
1483 depends on CMDLINE_BOOL
1485 Set this option to 'Y' to have the kernel ignore the boot loader
1486 command line, and use ONLY the built-in command line.
1488 This is used to work around broken boot loaders. This should
1489 be set to 'N' under normal conditions.
1493 config ARCH_ENABLE_MEMORY_HOTPLUG
1495 depends on X86_64 || (X86_32 && HIGHMEM)
1497 config HAVE_ARCH_EARLY_PFN_TO_NID
1501 menu "Power management options"
1502 depends on !X86_VOYAGER
1504 config ARCH_HIBERNATION_HEADER
1506 depends on X86_64 && HIBERNATION
1508 source "kernel/power/Kconfig"
1510 source "drivers/acpi/Kconfig"
1515 depends on APM || APM_MODULE
1518 tristate "APM (Advanced Power Management) BIOS support"
1519 depends on X86_32 && PM_SLEEP
1521 APM is a BIOS specification for saving power using several different
1522 techniques. This is mostly useful for battery powered laptops with
1523 APM compliant BIOSes. If you say Y here, the system time will be
1524 reset after a RESUME operation, the /proc/apm device will provide
1525 battery status information, and user-space programs will receive
1526 notification of APM "events" (e.g. battery status change).
1528 If you select "Y" here, you can disable actual use of the APM
1529 BIOS by passing the "apm=off" option to the kernel at boot time.
1531 Note that the APM support is almost completely disabled for
1532 machines with more than one CPU.
1534 In order to use APM, you will need supporting software. For location
1535 and more information, read <file:Documentation/power/pm.txt> and the
1536 Battery Powered Linux mini-HOWTO, available from
1537 <http://www.tldp.org/docs.html#howto>.
1539 This driver does not spin down disk drives (see the hdparm(8)
1540 manpage ("man 8 hdparm") for that), and it doesn't turn off
1541 VESA-compliant "green" monitors.
1543 This driver does not support the TI 4000M TravelMate and the ACER
1544 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1545 desktop machines also don't have compliant BIOSes, and this driver
1546 may cause those machines to panic during the boot phase.
1548 Generally, if you don't have a battery in your machine, there isn't
1549 much point in using this driver and you should say N. If you get
1550 random kernel OOPSes or reboots that don't seem to be related to
1551 anything, try disabling/enabling this option (or disabling/enabling
1554 Some other things you should try when experiencing seemingly random,
1557 1) make sure that you have enough swap space and that it is
1559 2) pass the "no-hlt" option to the kernel
1560 3) switch on floating point emulation in the kernel and pass
1561 the "no387" option to the kernel
1562 4) pass the "floppy=nodma" option to the kernel
1563 5) pass the "mem=4M" option to the kernel (thereby disabling
1564 all but the first 4 MB of RAM)
1565 6) make sure that the CPU is not over clocked.
1566 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1567 8) disable the cache from your BIOS settings
1568 9) install a fan for the video card or exchange video RAM
1569 10) install a better fan for the CPU
1570 11) exchange RAM chips
1571 12) exchange the motherboard.
1573 To compile this driver as a module, choose M here: the
1574 module will be called apm.
1578 config APM_IGNORE_USER_SUSPEND
1579 bool "Ignore USER SUSPEND"
1581 This option will ignore USER SUSPEND requests. On machines with a
1582 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1583 series notebooks, it is necessary to say Y because of a BIOS bug.
1585 config APM_DO_ENABLE
1586 bool "Enable PM at boot time"
1588 Enable APM features at boot time. From page 36 of the APM BIOS
1589 specification: "When disabled, the APM BIOS does not automatically
1590 power manage devices, enter the Standby State, enter the Suspend
1591 State, or take power saving steps in response to CPU Idle calls."
1592 This driver will make CPU Idle calls when Linux is idle (unless this
1593 feature is turned off -- see "Do CPU IDLE calls", below). This
1594 should always save battery power, but more complicated APM features
1595 will be dependent on your BIOS implementation. You may need to turn
1596 this option off if your computer hangs at boot time when using APM
1597 support, or if it beeps continuously instead of suspending. Turn
1598 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1599 T400CDT. This is off by default since most machines do fine without
1603 bool "Make CPU Idle calls when idle"
1605 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1606 On some machines, this can activate improved power savings, such as
1607 a slowed CPU clock rate, when the machine is idle. These idle calls
1608 are made after the idle loop has run for some length of time (e.g.,
1609 333 mS). On some machines, this will cause a hang at boot time or
1610 whenever the CPU becomes idle. (On machines with more than one CPU,
1611 this option does nothing.)
1613 config APM_DISPLAY_BLANK
1614 bool "Enable console blanking using APM"
1616 Enable console blanking using the APM. Some laptops can use this to
1617 turn off the LCD backlight when the screen blanker of the Linux
1618 virtual console blanks the screen. Note that this is only used by
1619 the virtual console screen blanker, and won't turn off the backlight
1620 when using the X Window system. This also doesn't have anything to
1621 do with your VESA-compliant power-saving monitor. Further, this
1622 option doesn't work for all laptops -- it might not turn off your
1623 backlight at all, or it might print a lot of errors to the console,
1624 especially if you are using gpm.
1626 config APM_ALLOW_INTS
1627 bool "Allow interrupts during APM BIOS calls"
1629 Normally we disable external interrupts while we are making calls to
1630 the APM BIOS as a measure to lessen the effects of a badly behaving
1631 BIOS implementation. The BIOS should reenable interrupts if it
1632 needs to. Unfortunately, some BIOSes do not -- especially those in
1633 many of the newer IBM Thinkpads. If you experience hangs when you
1634 suspend, try setting this to Y. Otherwise, say N.
1636 config APM_REAL_MODE_POWER_OFF
1637 bool "Use real mode APM BIOS call to power off"
1639 Use real mode APM BIOS calls to switch off the computer. This is
1640 a work-around for a number of buggy BIOSes. Switch this option on if
1641 your computer crashes instead of powering off properly.
1645 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1647 source "drivers/cpuidle/Kconfig"
1652 menu "Bus options (PCI etc.)"
1657 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1659 Find out whether you have a PCI motherboard. PCI is the name of a
1660 bus system, i.e. the way the CPU talks to the other stuff inside
1661 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1662 VESA. If you have PCI, say Y, otherwise N.
1665 prompt "PCI access mode"
1666 depends on X86_32 && PCI
1669 On PCI systems, the BIOS can be used to detect the PCI devices and
1670 determine their configuration. However, some old PCI motherboards
1671 have BIOS bugs and may crash if this is done. Also, some embedded
1672 PCI-based systems don't have any BIOS at all. Linux can also try to
1673 detect the PCI hardware directly without using the BIOS.
1675 With this option, you can specify how Linux should detect the
1676 PCI devices. If you choose "BIOS", the BIOS will be used,
1677 if you choose "Direct", the BIOS won't be used, and if you
1678 choose "MMConfig", then PCI Express MMCONFIG will be used.
1679 If you choose "Any", the kernel will try MMCONFIG, then the
1680 direct access method and falls back to the BIOS if that doesn't
1681 work. If unsure, go with the default, which is "Any".
1686 config PCI_GOMMCONFIG
1703 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1705 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1708 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1712 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1716 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1723 bool "Support mmconfig PCI config space access"
1724 depends on X86_64 && PCI && ACPI
1727 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1728 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1730 DMA remapping (DMAR) devices support enables independent address
1731 translations for Direct Memory Access (DMA) from devices.
1732 These DMA remapping devices are reported via ACPI tables
1733 and include PCI device scope covered by these DMA
1738 prompt "Support for Graphics workaround"
1741 Current Graphics drivers tend to use physical address
1742 for DMA and avoid using DMA APIs. Setting this config
1743 option permits the IOMMU driver to set a unity map for
1744 all the OS-visible memory. Hence the driver can continue
1745 to use physical addresses for DMA.
1747 config DMAR_FLOPPY_WA
1751 Floppy disk drivers are know to bypass DMA API calls
1752 thereby failing to work when IOMMU is enabled. This
1753 workaround will setup a 1:1 mapping for the first
1754 16M to make floppy (an ISA device) work.
1757 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1758 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1760 Supports Interrupt remapping for IO-APIC and MSI devices.
1761 To use x2apic mode in the CPU's which support x2APIC enhancements or
1762 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1764 source "drivers/pci/pcie/Kconfig"
1766 source "drivers/pci/Kconfig"
1768 # x86_64 have no ISA slots, but do have ISA-style DMA.
1776 depends on !X86_VOYAGER
1778 Find out whether you have ISA slots on your motherboard. ISA is the
1779 name of a bus system, i.e. the way the CPU talks to the other stuff
1780 inside your box. Other bus systems are PCI, EISA, MicroChannel
1781 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1782 newer boards don't support it. If you have ISA, say Y, otherwise N.
1788 The Extended Industry Standard Architecture (EISA) bus was
1789 developed as an open alternative to the IBM MicroChannel bus.
1791 The EISA bus provided some of the features of the IBM MicroChannel
1792 bus while maintaining backward compatibility with cards made for
1793 the older ISA bus. The EISA bus saw limited use between 1988 and
1794 1995 when it was made obsolete by the PCI bus.
1796 Say Y here if you are building a kernel for an EISA-based machine.
1800 source "drivers/eisa/Kconfig"
1803 bool "MCA support" if !X86_VOYAGER
1804 default y if X86_VOYAGER
1806 MicroChannel Architecture is found in some IBM PS/2 machines and
1807 laptops. It is a bus system similar to PCI or ISA. See
1808 <file:Documentation/mca.txt> (and especially the web page given
1809 there) before attempting to build an MCA bus kernel.
1811 source "drivers/mca/Kconfig"
1814 tristate "NatSemi SCx200 support"
1815 depends on !X86_VOYAGER
1817 This provides basic support for National Semiconductor's
1818 (now AMD's) Geode processors. The driver probes for the
1819 PCI-IDs of several on-chip devices, so its a good dependency
1820 for other scx200_* drivers.
1822 If compiled as a module, the driver is named scx200.
1824 config SCx200HR_TIMER
1825 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1826 depends on SCx200 && GENERIC_TIME
1829 This driver provides a clocksource built upon the on-chip
1830 27MHz high-resolution timer. Its also a workaround for
1831 NSC Geode SC-1100's buggy TSC, which loses time when the
1832 processor goes idle (as is done by the scheduler). The
1833 other workaround is idle=poll boot option.
1835 config GEODE_MFGPT_TIMER
1837 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1838 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1840 This driver provides a clock event source based on the MFGPT
1841 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1842 MFGPTs have a better resolution and max interval than the
1843 generic PIT, and are suitable for use as high-res timers.
1846 bool "One Laptop Per Child support"
1849 Add support for detecting the unique features of the OLPC
1856 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1858 source "drivers/pcmcia/Kconfig"
1860 source "drivers/pci/hotplug/Kconfig"
1865 menu "Executable file formats / Emulations"
1867 source "fs/Kconfig.binfmt"
1869 config IA32_EMULATION
1870 bool "IA32 Emulation"
1872 select COMPAT_BINFMT_ELF
1874 Include code to run 32-bit programs under a 64-bit kernel. You should
1875 likely turn this on, unless you're 100% sure that you don't have any
1876 32-bit programs left.
1879 tristate "IA32 a.out support"
1880 depends on IA32_EMULATION
1882 Support old a.out binaries in the 32bit emulation.
1886 depends on IA32_EMULATION
1888 config COMPAT_FOR_U64_ALIGNMENT
1892 config SYSVIPC_COMPAT
1894 depends on COMPAT && SYSVIPC
1899 source "net/Kconfig"
1901 source "drivers/Kconfig"
1903 source "drivers/firmware/Kconfig"
1907 source "arch/x86/Kconfig.debug"
1909 source "security/Kconfig"
1911 source "crypto/Kconfig"
1913 source "arch/x86/kvm/Kconfig"
1915 source "lib/Kconfig"
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