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_FTRACE_MCOUNT_RECORD
30 select HAVE_DYNAMIC_FTRACE
31 select HAVE_FUNCTION_TRACER
32 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
33 select HAVE_ARCH_KGDB if !X86_VOYAGER
34 select HAVE_ARCH_TRACEHOOK
35 select HAVE_GENERIC_DMA_COHERENT if X86_32
36 select HAVE_EFFICIENT_UNALIGNED_ACCESS
40 default "arch/x86/configs/i386_defconfig" if X86_32
41 default "arch/x86/configs/x86_64_defconfig" if X86_64
46 config GENERIC_CMOS_UPDATE
49 config CLOCKSOURCE_WATCHDOG
52 config GENERIC_CLOCKEVENTS
55 config GENERIC_CLOCKEVENTS_BROADCAST
57 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
59 config LOCKDEP_SUPPORT
62 config STACKTRACE_SUPPORT
65 config HAVE_LATENCYTOP_SUPPORT
68 config FAST_CMPXCHG_LOCAL
81 config GENERIC_ISA_DMA
91 config GENERIC_HWEIGHT
97 config ARCH_MAY_HAVE_PC_FDC
100 config RWSEM_GENERIC_SPINLOCK
103 config RWSEM_XCHGADD_ALGORITHM
106 config ARCH_HAS_CPU_IDLE_WAIT
109 config GENERIC_CALIBRATE_DELAY
112 config GENERIC_TIME_VSYSCALL
116 config ARCH_HAS_CPU_RELAX
119 config ARCH_HAS_DEFAULT_IDLE
122 config ARCH_HAS_CACHE_LINE_SIZE
125 config HAVE_SETUP_PER_CPU_AREA
126 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
128 config HAVE_CPUMASK_OF_CPU_MAP
131 config ARCH_HIBERNATION_POSSIBLE
133 depends on !SMP || !X86_VOYAGER
135 config ARCH_SUSPEND_POSSIBLE
137 depends on !X86_VOYAGER
143 config ARCH_POPULATES_NODE_MAP
150 config ARCH_SUPPORTS_OPTIMIZED_INLINING
153 # Use the generic interrupt handling code in kernel/irq/:
154 config GENERIC_HARDIRQS
158 config GENERIC_IRQ_PROBE
162 config GENERIC_PENDING_IRQ
164 depends on GENERIC_HARDIRQS && SMP
169 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
172 config USE_GENERIC_SMP_HELPERS
178 depends on X86_32 && SMP
182 depends on X86_64 && SMP
187 depends on (X86_32 && !X86_VOYAGER) || X86_64
190 config X86_BIOS_REBOOT
192 depends on !X86_VOYAGER
195 config X86_TRAMPOLINE
197 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
202 source "init/Kconfig"
203 source "kernel/Kconfig.freezer"
205 menu "Processor type and features"
207 source "kernel/time/Kconfig"
210 bool "Symmetric multi-processing support"
212 This enables support for systems with more than one CPU. If you have
213 a system with only one CPU, like most personal computers, say N. If
214 you have a system with more than one CPU, say Y.
216 If you say N here, the kernel will run on single and multiprocessor
217 machines, but will use only one CPU of a multiprocessor machine. If
218 you say Y here, the kernel will run on many, but not all,
219 singleprocessor machines. On a singleprocessor machine, the kernel
220 will run faster if you say N here.
222 Note that if you say Y here and choose architecture "586" or
223 "Pentium" under "Processor family", the kernel will not work on 486
224 architectures. Similarly, multiprocessor kernels for the "PPro"
225 architecture may not work on all Pentium based boards.
227 People using multiprocessor machines who say Y here should also say
228 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
229 Management" code will be disabled if you say Y here.
231 See also <file:Documentation/i386/IO-APIC.txt>,
232 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
233 <http://www.tldp.org/docs.html#howto>.
235 If you don't know what to do here, say N.
237 config X86_HAS_BOOT_CPU_ID
239 depends on X86_VOYAGER
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
763 bool "Enable X86 board specific fixups for reboot"
766 This enables chipset and/or board specific fixups to be done
767 in order to get reboot to work correctly. This is only needed on
768 some combinations of hardware and BIOS. The symptom, for which
769 this config is intended, is when reboot ends with a stalled/hung
772 Currently, the only fixup is for the Geode machines using
773 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
775 Say Y if you want to enable the fixup. Currently, it's safe to
776 enable this option even if you don't need it.
780 tristate "/dev/cpu/microcode - microcode support"
783 If you say Y here, you will be able to update the microcode on
784 certain Intel and AMD processors. The Intel support is for the
785 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
786 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
787 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
788 You will obviously need the actual microcode binary data itself
789 which is not shipped with the Linux kernel.
791 This option selects the general module only, you need to select
792 at least one vendor specific module as well.
794 To compile this driver as a module, choose M here: the
795 module will be called microcode.
797 config MICROCODE_INTEL
798 bool "Intel microcode patch loading support"
803 This options enables microcode patch loading support for Intel
806 For latest news and information on obtaining all the required
807 Intel ingredients for this driver, check:
808 <http://www.urbanmyth.org/microcode/>.
811 bool "AMD microcode patch loading support"
815 If you select this option, microcode patch loading support for AMD
816 processors will be enabled.
818 config MICROCODE_OLD_INTERFACE
823 tristate "/dev/cpu/*/msr - Model-specific register support"
825 This device gives privileged processes access to the x86
826 Model-Specific Registers (MSRs). It is a character device with
827 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
828 MSR accesses are directed to a specific CPU on multi-processor
832 tristate "/dev/cpu/*/cpuid - CPU information support"
834 This device gives processes access to the x86 CPUID instruction to
835 be executed on a specific processor. It is a character device
836 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
840 prompt "High Memory Support"
841 default HIGHMEM4G if !X86_NUMAQ
842 default HIGHMEM64G if X86_NUMAQ
847 depends on !X86_NUMAQ
849 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
850 However, the address space of 32-bit x86 processors is only 4
851 Gigabytes large. That means that, if you have a large amount of
852 physical memory, not all of it can be "permanently mapped" by the
853 kernel. The physical memory that's not permanently mapped is called
856 If you are compiling a kernel which will never run on a machine with
857 more than 1 Gigabyte total physical RAM, answer "off" here (default
858 choice and suitable for most users). This will result in a "3GB/1GB"
859 split: 3GB are mapped so that each process sees a 3GB virtual memory
860 space and the remaining part of the 4GB virtual memory space is used
861 by the kernel to permanently map as much physical memory as
864 If the machine has between 1 and 4 Gigabytes physical RAM, then
867 If more than 4 Gigabytes is used then answer "64GB" here. This
868 selection turns Intel PAE (Physical Address Extension) mode on.
869 PAE implements 3-level paging on IA32 processors. PAE is fully
870 supported by Linux, PAE mode is implemented on all recent Intel
871 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
872 then the kernel will not boot on CPUs that don't support PAE!
874 The actual amount of total physical memory will either be
875 auto detected or can be forced by using a kernel command line option
876 such as "mem=256M". (Try "man bootparam" or see the documentation of
877 your boot loader (lilo or loadlin) about how to pass options to the
878 kernel at boot time.)
880 If unsure, say "off".
884 depends on !X86_NUMAQ
886 Select this if you have a 32-bit processor and between 1 and 4
887 gigabytes of physical RAM.
891 depends on !M386 && !M486
894 Select this if you have a 32-bit processor and more than 4
895 gigabytes of physical RAM.
900 depends on EXPERIMENTAL
901 prompt "Memory split" if EMBEDDED
905 Select the desired split between kernel and user memory.
907 If the address range available to the kernel is less than the
908 physical memory installed, the remaining memory will be available
909 as "high memory". Accessing high memory is a little more costly
910 than low memory, as it needs to be mapped into the kernel first.
911 Note that increasing the kernel address space limits the range
912 available to user programs, making the address space there
913 tighter. Selecting anything other than the default 3G/1G split
914 will also likely make your kernel incompatible with binary-only
917 If you are not absolutely sure what you are doing, leave this
921 bool "3G/1G user/kernel split"
922 config VMSPLIT_3G_OPT
924 bool "3G/1G user/kernel split (for full 1G low memory)"
926 bool "2G/2G user/kernel split"
927 config VMSPLIT_2G_OPT
929 bool "2G/2G user/kernel split (for full 2G low memory)"
931 bool "1G/3G user/kernel split"
936 default 0xB0000000 if VMSPLIT_3G_OPT
937 default 0x80000000 if VMSPLIT_2G
938 default 0x78000000 if VMSPLIT_2G_OPT
939 default 0x40000000 if VMSPLIT_1G
945 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
948 bool "PAE (Physical Address Extension) Support"
949 depends on X86_32 && !HIGHMEM4G
951 PAE is required for NX support, and furthermore enables
952 larger swapspace support for non-overcommit purposes. It
953 has the cost of more pagetable lookup overhead, and also
954 consumes more pagetable space per process.
956 config ARCH_PHYS_ADDR_T_64BIT
957 def_bool X86_64 || X86_PAE
959 config DIRECT_GBPAGES
960 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
964 Allow the kernel linear mapping to use 1GB pages on CPUs that
965 support it. This can improve the kernel's performance a tiny bit by
966 reducing TLB pressure. If in doubt, say "Y".
968 # Common NUMA Features
970 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
972 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
974 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
976 Enable NUMA (Non Uniform Memory Access) support.
977 The kernel will try to allocate memory used by a CPU on the
978 local memory controller of the CPU and add some more
979 NUMA awareness to the kernel.
981 For 32-bit this is currently highly experimental and should be only
982 used for kernel development. It might also cause boot failures.
983 For 64-bit this is recommended on all multiprocessor Opteron systems.
984 If the system is EM64T, you should say N unless your system is
987 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
988 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
992 prompt "Old style AMD Opteron NUMA detection"
993 depends on X86_64 && NUMA && PCI
995 Enable K8 NUMA node topology detection. You should say Y here if
996 you have a multi processor AMD K8 system. This uses an old
997 method to read the NUMA configuration directly from the builtin
998 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
999 instead, which also takes priority if both are compiled in.
1001 config X86_64_ACPI_NUMA
1003 prompt "ACPI NUMA detection"
1004 depends on X86_64 && NUMA && ACPI && PCI
1007 Enable ACPI SRAT based node topology detection.
1009 # Some NUMA nodes have memory ranges that span
1010 # other nodes. Even though a pfn is valid and
1011 # between a node's start and end pfns, it may not
1012 # reside on that node. See memmap_init_zone()
1014 config NODES_SPAN_OTHER_NODES
1016 depends on X86_64_ACPI_NUMA
1019 bool "NUMA emulation"
1020 depends on X86_64 && NUMA
1022 Enable NUMA emulation. A flat machine will be split
1023 into virtual nodes when booted with "numa=fake=N", where N is the
1024 number of nodes. This is only useful for debugging.
1027 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1029 default "9" if MAXSMP
1030 default "6" if X86_64
1031 default "4" if X86_NUMAQ
1033 depends on NEED_MULTIPLE_NODES
1035 Specify the maximum number of NUMA Nodes available on the target
1036 system. Increases memory reserved to accomodate various tables.
1038 config HAVE_ARCH_BOOTMEM_NODE
1040 depends on X86_32 && NUMA
1042 config ARCH_HAVE_MEMORY_PRESENT
1044 depends on X86_32 && DISCONTIGMEM
1046 config NEED_NODE_MEMMAP_SIZE
1048 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1050 config HAVE_ARCH_ALLOC_REMAP
1052 depends on X86_32 && NUMA
1054 config ARCH_FLATMEM_ENABLE
1056 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1058 config ARCH_DISCONTIGMEM_ENABLE
1060 depends on NUMA && X86_32
1062 config ARCH_DISCONTIGMEM_DEFAULT
1064 depends on NUMA && X86_32
1066 config ARCH_SPARSEMEM_DEFAULT
1070 config ARCH_SPARSEMEM_ENABLE
1072 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1073 select SPARSEMEM_STATIC if X86_32
1074 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1076 config ARCH_SELECT_MEMORY_MODEL
1078 depends on ARCH_SPARSEMEM_ENABLE
1080 config ARCH_MEMORY_PROBE
1082 depends on MEMORY_HOTPLUG
1087 bool "Allocate 3rd-level pagetables from highmem"
1088 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1090 The VM uses one page table entry for each page of physical memory.
1091 For systems with a lot of RAM, this can be wasteful of precious
1092 low memory. Setting this option will put user-space page table
1093 entries in high memory.
1095 config X86_CHECK_BIOS_CORRUPTION
1096 bool "Check for low memory corruption"
1098 Periodically check for memory corruption in low memory, which
1099 is suspected to be caused by BIOS. Even when enabled in the
1100 configuration, it is disabled at runtime. Enable it by
1101 setting "memory_corruption_check=1" on the kernel command
1102 line. By default it scans the low 64k of memory every 60
1103 seconds; see the memory_corruption_check_size and
1104 memory_corruption_check_period parameters in
1105 Documentation/kernel-parameters.txt to adjust this.
1107 When enabled with the default parameters, this option has
1108 almost no overhead, as it reserves a relatively small amount
1109 of memory and scans it infrequently. It both detects corruption
1110 and prevents it from affecting the running system.
1112 It is, however, intended as a diagnostic tool; if repeatable
1113 BIOS-originated corruption always affects the same memory,
1114 you can use memmap= to prevent the kernel from using that
1117 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1118 bool "Set the default setting of memory_corruption_check"
1119 depends on X86_CHECK_BIOS_CORRUPTION
1122 Set whether the default state of memory_corruption_check is
1125 config X86_RESERVE_LOW_64K
1126 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1129 Reserve the first 64K of physical RAM on BIOSes that are known
1130 to potentially corrupt that memory range. A numbers of BIOSes are
1131 known to utilize this area during suspend/resume, so it must not
1132 be used by the kernel.
1134 Set this to N if you are absolutely sure that you trust the BIOS
1135 to get all its memory reservations and usages right.
1137 If you have doubts about the BIOS (e.g. suspend/resume does not
1138 work or there's kernel crashes after certain hardware hotplug
1139 events) and it's not AMI or Phoenix, then you might want to enable
1140 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1141 corruption patterns.
1145 config MATH_EMULATION
1147 prompt "Math emulation" if X86_32
1149 Linux can emulate a math coprocessor (used for floating point
1150 operations) if you don't have one. 486DX and Pentium processors have
1151 a math coprocessor built in, 486SX and 386 do not, unless you added
1152 a 487DX or 387, respectively. (The messages during boot time can
1153 give you some hints here ["man dmesg"].) Everyone needs either a
1154 coprocessor or this emulation.
1156 If you don't have a math coprocessor, you need to say Y here; if you
1157 say Y here even though you have a coprocessor, the coprocessor will
1158 be used nevertheless. (This behavior can be changed with the kernel
1159 command line option "no387", which comes handy if your coprocessor
1160 is broken. Try "man bootparam" or see the documentation of your boot
1161 loader (lilo or loadlin) about how to pass options to the kernel at
1162 boot time.) This means that it is a good idea to say Y here if you
1163 intend to use this kernel on different machines.
1165 More information about the internals of the Linux math coprocessor
1166 emulation can be found in <file:arch/x86/math-emu/README>.
1168 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1169 kernel, it won't hurt.
1172 bool "MTRR (Memory Type Range Register) support"
1174 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1175 the Memory Type Range Registers (MTRRs) may be used to control
1176 processor access to memory ranges. This is most useful if you have
1177 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1178 allows bus write transfers to be combined into a larger transfer
1179 before bursting over the PCI/AGP bus. This can increase performance
1180 of image write operations 2.5 times or more. Saying Y here creates a
1181 /proc/mtrr file which may be used to manipulate your processor's
1182 MTRRs. Typically the X server should use this.
1184 This code has a reasonably generic interface so that similar
1185 control registers on other processors can be easily supported
1188 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1189 Registers (ARRs) which provide a similar functionality to MTRRs. For
1190 these, the ARRs are used to emulate the MTRRs.
1191 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1192 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1193 write-combining. All of these processors are supported by this code
1194 and it makes sense to say Y here if you have one of them.
1196 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1197 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1198 can lead to all sorts of problems, so it's good to say Y here.
1200 You can safely say Y even if your machine doesn't have MTRRs, you'll
1201 just add about 9 KB to your kernel.
1203 See <file:Documentation/x86/mtrr.txt> for more information.
1205 config MTRR_SANITIZER
1207 prompt "MTRR cleanup support"
1210 Convert MTRR layout from continuous to discrete, so X drivers can
1211 add writeback entries.
1213 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1214 The largest mtrr entry size for a continous block can be set with
1219 config MTRR_SANITIZER_ENABLE_DEFAULT
1220 int "MTRR cleanup enable value (0-1)"
1223 depends on MTRR_SANITIZER
1225 Enable mtrr cleanup default value
1227 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1228 int "MTRR cleanup spare reg num (0-7)"
1231 depends on MTRR_SANITIZER
1233 mtrr cleanup spare entries default, it can be changed via
1234 mtrr_spare_reg_nr=N on the kernel command line.
1238 prompt "x86 PAT support"
1241 Use PAT attributes to setup page level cache control.
1243 PATs are the modern equivalents of MTRRs and are much more
1244 flexible than MTRRs.
1246 Say N here if you see bootup problems (boot crash, boot hang,
1247 spontaneous reboots) or a non-working video driver.
1252 bool "EFI runtime service support"
1255 This enables the kernel to use EFI runtime services that are
1256 available (such as the EFI variable services).
1258 This option is only useful on systems that have EFI firmware.
1259 In addition, you should use the latest ELILO loader available
1260 at <http://elilo.sourceforge.net> in order to take advantage
1261 of EFI runtime services. However, even with this option, the
1262 resultant kernel should continue to boot on existing non-EFI
1267 prompt "Enable seccomp to safely compute untrusted bytecode"
1269 This kernel feature is useful for number crunching applications
1270 that may need to compute untrusted bytecode during their
1271 execution. By using pipes or other transports made available to
1272 the process as file descriptors supporting the read/write
1273 syscalls, it's possible to isolate those applications in
1274 their own address space using seccomp. Once seccomp is
1275 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1276 and the task is only allowed to execute a few safe syscalls
1277 defined by each seccomp mode.
1279 If unsure, say Y. Only embedded should say N here.
1281 config CC_STACKPROTECTOR
1282 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1283 depends on X86_64 && EXPERIMENTAL && BROKEN
1285 This option turns on the -fstack-protector GCC feature. This
1286 feature puts, at the beginning of critical functions, a canary
1287 value on the stack just before the return address, and validates
1288 the value just before actually returning. Stack based buffer
1289 overflows (that need to overwrite this return address) now also
1290 overwrite the canary, which gets detected and the attack is then
1291 neutralized via a kernel panic.
1293 This feature requires gcc version 4.2 or above, or a distribution
1294 gcc with the feature backported. Older versions are automatically
1295 detected and for those versions, this configuration option is ignored.
1297 config CC_STACKPROTECTOR_ALL
1298 bool "Use stack-protector for all functions"
1299 depends on CC_STACKPROTECTOR
1301 Normally, GCC only inserts the canary value protection for
1302 functions that use large-ish on-stack buffers. By enabling
1303 this option, GCC will be asked to do this for ALL functions.
1305 source kernel/Kconfig.hz
1308 bool "kexec system call"
1309 depends on X86_BIOS_REBOOT
1311 kexec is a system call that implements the ability to shutdown your
1312 current kernel, and to start another kernel. It is like a reboot
1313 but it is independent of the system firmware. And like a reboot
1314 you can start any kernel with it, not just Linux.
1316 The name comes from the similarity to the exec system call.
1318 It is an ongoing process to be certain the hardware in a machine
1319 is properly shutdown, so do not be surprised if this code does not
1320 initially work for you. It may help to enable device hotplugging
1321 support. As of this writing the exact hardware interface is
1322 strongly in flux, so no good recommendation can be made.
1325 bool "kernel crash dumps"
1326 depends on X86_64 || (X86_32 && HIGHMEM)
1328 Generate crash dump after being started by kexec.
1329 This should be normally only set in special crash dump kernels
1330 which are loaded in the main kernel with kexec-tools into
1331 a specially reserved region and then later executed after
1332 a crash by kdump/kexec. The crash dump kernel must be compiled
1333 to a memory address not used by the main kernel or BIOS using
1334 PHYSICAL_START, or it must be built as a relocatable image
1335 (CONFIG_RELOCATABLE=y).
1336 For more details see Documentation/kdump/kdump.txt
1339 bool "kexec jump (EXPERIMENTAL)"
1340 depends on EXPERIMENTAL
1341 depends on KEXEC && HIBERNATION && X86_32
1343 Jump between original kernel and kexeced kernel and invoke
1344 code in physical address mode via KEXEC
1346 config PHYSICAL_START
1347 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1348 default "0x1000000" if X86_NUMAQ
1349 default "0x200000" if X86_64
1352 This gives the physical address where the kernel is loaded.
1354 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1355 bzImage will decompress itself to above physical address and
1356 run from there. Otherwise, bzImage will run from the address where
1357 it has been loaded by the boot loader and will ignore above physical
1360 In normal kdump cases one does not have to set/change this option
1361 as now bzImage can be compiled as a completely relocatable image
1362 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1363 address. This option is mainly useful for the folks who don't want
1364 to use a bzImage for capturing the crash dump and want to use a
1365 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1366 to be specifically compiled to run from a specific memory area
1367 (normally a reserved region) and this option comes handy.
1369 So if you are using bzImage for capturing the crash dump, leave
1370 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1371 Otherwise if you plan to use vmlinux for capturing the crash dump
1372 change this value to start of the reserved region (Typically 16MB
1373 0x1000000). In other words, it can be set based on the "X" value as
1374 specified in the "crashkernel=YM@XM" command line boot parameter
1375 passed to the panic-ed kernel. Typically this parameter is set as
1376 crashkernel=64M@16M. Please take a look at
1377 Documentation/kdump/kdump.txt for more details about crash dumps.
1379 Usage of bzImage for capturing the crash dump is recommended as
1380 one does not have to build two kernels. Same kernel can be used
1381 as production kernel and capture kernel. Above option should have
1382 gone away after relocatable bzImage support is introduced. But it
1383 is present because there are users out there who continue to use
1384 vmlinux for dump capture. This option should go away down the
1387 Don't change this unless you know what you are doing.
1390 bool "Build a relocatable kernel (EXPERIMENTAL)"
1391 depends on EXPERIMENTAL
1393 This builds a kernel image that retains relocation information
1394 so it can be loaded someplace besides the default 1MB.
1395 The relocations tend to make the kernel binary about 10% larger,
1396 but are discarded at runtime.
1398 One use is for the kexec on panic case where the recovery kernel
1399 must live at a different physical address than the primary
1402 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1403 it has been loaded at and the compile time physical address
1404 (CONFIG_PHYSICAL_START) is ignored.
1406 config PHYSICAL_ALIGN
1408 prompt "Alignment value to which kernel should be aligned" if X86_32
1409 default "0x100000" if X86_32
1410 default "0x200000" if X86_64
1411 range 0x2000 0x400000
1413 This value puts the alignment restrictions on physical address
1414 where kernel is loaded and run from. Kernel is compiled for an
1415 address which meets above alignment restriction.
1417 If bootloader loads the kernel at a non-aligned address and
1418 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1419 address aligned to above value and run from there.
1421 If bootloader loads the kernel at a non-aligned address and
1422 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1423 load address and decompress itself to the address it has been
1424 compiled for and run from there. The address for which kernel is
1425 compiled already meets above alignment restrictions. Hence the
1426 end result is that kernel runs from a physical address meeting
1427 above alignment restrictions.
1429 Don't change this unless you know what you are doing.
1432 bool "Support for hot-pluggable CPUs"
1433 depends on SMP && HOTPLUG && !X86_VOYAGER
1435 Say Y here to allow turning CPUs off and on. CPUs can be
1436 controlled through /sys/devices/system/cpu.
1437 ( Note: power management support will enable this option
1438 automatically on SMP systems. )
1439 Say N if you want to disable CPU hotplug.
1443 prompt "Compat VDSO support"
1444 depends on X86_32 || IA32_EMULATION
1446 Map the 32-bit VDSO to the predictable old-style address too.
1448 Say N here if you are running a sufficiently recent glibc
1449 version (2.3.3 or later), to remove the high-mapped
1450 VDSO mapping and to exclusively use the randomized VDSO.
1455 bool "Built-in kernel command line"
1458 Allow for specifying boot arguments to the kernel at
1459 build time. On some systems (e.g. embedded ones), it is
1460 necessary or convenient to provide some or all of the
1461 kernel boot arguments with the kernel itself (that is,
1462 to not rely on the boot loader to provide them.)
1464 To compile command line arguments into the kernel,
1465 set this option to 'Y', then fill in the
1466 the boot arguments in CONFIG_CMDLINE.
1468 Systems with fully functional boot loaders (i.e. non-embedded)
1469 should leave this option set to 'N'.
1472 string "Built-in kernel command string"
1473 depends on CMDLINE_BOOL
1476 Enter arguments here that should be compiled into the kernel
1477 image and used at boot time. If the boot loader provides a
1478 command line at boot time, it is appended to this string to
1479 form the full kernel command line, when the system boots.
1481 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1482 change this behavior.
1484 In most cases, the command line (whether built-in or provided
1485 by the boot loader) should specify the device for the root
1488 config CMDLINE_OVERRIDE
1489 bool "Built-in command line overrides boot loader arguments"
1491 depends on CMDLINE_BOOL
1493 Set this option to 'Y' to have the kernel ignore the boot loader
1494 command line, and use ONLY the built-in command line.
1496 This is used to work around broken boot loaders. This should
1497 be set to 'N' under normal conditions.
1501 config ARCH_ENABLE_MEMORY_HOTPLUG
1503 depends on X86_64 || (X86_32 && HIGHMEM)
1505 config ARCH_ENABLE_MEMORY_HOTREMOVE
1507 depends on MEMORY_HOTPLUG
1509 config HAVE_ARCH_EARLY_PFN_TO_NID
1513 menu "Power management and ACPI options"
1514 depends on !X86_VOYAGER
1516 config ARCH_HIBERNATION_HEADER
1518 depends on X86_64 && HIBERNATION
1520 source "kernel/power/Kconfig"
1522 source "drivers/acpi/Kconfig"
1527 depends on APM || APM_MODULE
1530 tristate "APM (Advanced Power Management) BIOS support"
1531 depends on X86_32 && PM_SLEEP
1533 APM is a BIOS specification for saving power using several different
1534 techniques. This is mostly useful for battery powered laptops with
1535 APM compliant BIOSes. If you say Y here, the system time will be
1536 reset after a RESUME operation, the /proc/apm device will provide
1537 battery status information, and user-space programs will receive
1538 notification of APM "events" (e.g. battery status change).
1540 If you select "Y" here, you can disable actual use of the APM
1541 BIOS by passing the "apm=off" option to the kernel at boot time.
1543 Note that the APM support is almost completely disabled for
1544 machines with more than one CPU.
1546 In order to use APM, you will need supporting software. For location
1547 and more information, read <file:Documentation/power/pm.txt> and the
1548 Battery Powered Linux mini-HOWTO, available from
1549 <http://www.tldp.org/docs.html#howto>.
1551 This driver does not spin down disk drives (see the hdparm(8)
1552 manpage ("man 8 hdparm") for that), and it doesn't turn off
1553 VESA-compliant "green" monitors.
1555 This driver does not support the TI 4000M TravelMate and the ACER
1556 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1557 desktop machines also don't have compliant BIOSes, and this driver
1558 may cause those machines to panic during the boot phase.
1560 Generally, if you don't have a battery in your machine, there isn't
1561 much point in using this driver and you should say N. If you get
1562 random kernel OOPSes or reboots that don't seem to be related to
1563 anything, try disabling/enabling this option (or disabling/enabling
1566 Some other things you should try when experiencing seemingly random,
1569 1) make sure that you have enough swap space and that it is
1571 2) pass the "no-hlt" option to the kernel
1572 3) switch on floating point emulation in the kernel and pass
1573 the "no387" option to the kernel
1574 4) pass the "floppy=nodma" option to the kernel
1575 5) pass the "mem=4M" option to the kernel (thereby disabling
1576 all but the first 4 MB of RAM)
1577 6) make sure that the CPU is not over clocked.
1578 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1579 8) disable the cache from your BIOS settings
1580 9) install a fan for the video card or exchange video RAM
1581 10) install a better fan for the CPU
1582 11) exchange RAM chips
1583 12) exchange the motherboard.
1585 To compile this driver as a module, choose M here: the
1586 module will be called apm.
1590 config APM_IGNORE_USER_SUSPEND
1591 bool "Ignore USER SUSPEND"
1593 This option will ignore USER SUSPEND requests. On machines with a
1594 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1595 series notebooks, it is necessary to say Y because of a BIOS bug.
1597 config APM_DO_ENABLE
1598 bool "Enable PM at boot time"
1600 Enable APM features at boot time. From page 36 of the APM BIOS
1601 specification: "When disabled, the APM BIOS does not automatically
1602 power manage devices, enter the Standby State, enter the Suspend
1603 State, or take power saving steps in response to CPU Idle calls."
1604 This driver will make CPU Idle calls when Linux is idle (unless this
1605 feature is turned off -- see "Do CPU IDLE calls", below). This
1606 should always save battery power, but more complicated APM features
1607 will be dependent on your BIOS implementation. You may need to turn
1608 this option off if your computer hangs at boot time when using APM
1609 support, or if it beeps continuously instead of suspending. Turn
1610 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1611 T400CDT. This is off by default since most machines do fine without
1615 bool "Make CPU Idle calls when idle"
1617 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1618 On some machines, this can activate improved power savings, such as
1619 a slowed CPU clock rate, when the machine is idle. These idle calls
1620 are made after the idle loop has run for some length of time (e.g.,
1621 333 mS). On some machines, this will cause a hang at boot time or
1622 whenever the CPU becomes idle. (On machines with more than one CPU,
1623 this option does nothing.)
1625 config APM_DISPLAY_BLANK
1626 bool "Enable console blanking using APM"
1628 Enable console blanking using the APM. Some laptops can use this to
1629 turn off the LCD backlight when the screen blanker of the Linux
1630 virtual console blanks the screen. Note that this is only used by
1631 the virtual console screen blanker, and won't turn off the backlight
1632 when using the X Window system. This also doesn't have anything to
1633 do with your VESA-compliant power-saving monitor. Further, this
1634 option doesn't work for all laptops -- it might not turn off your
1635 backlight at all, or it might print a lot of errors to the console,
1636 especially if you are using gpm.
1638 config APM_ALLOW_INTS
1639 bool "Allow interrupts during APM BIOS calls"
1641 Normally we disable external interrupts while we are making calls to
1642 the APM BIOS as a measure to lessen the effects of a badly behaving
1643 BIOS implementation. The BIOS should reenable interrupts if it
1644 needs to. Unfortunately, some BIOSes do not -- especially those in
1645 many of the newer IBM Thinkpads. If you experience hangs when you
1646 suspend, try setting this to Y. Otherwise, say N.
1648 config APM_REAL_MODE_POWER_OFF
1649 bool "Use real mode APM BIOS call to power off"
1651 Use real mode APM BIOS calls to switch off the computer. This is
1652 a work-around for a number of buggy BIOSes. Switch this option on if
1653 your computer crashes instead of powering off properly.
1657 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1659 source "drivers/cpuidle/Kconfig"
1661 source "drivers/idle/Kconfig"
1666 menu "Bus options (PCI etc.)"
1671 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1673 Find out whether you have a PCI motherboard. PCI is the name of a
1674 bus system, i.e. the way the CPU talks to the other stuff inside
1675 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1676 VESA. If you have PCI, say Y, otherwise N.
1679 prompt "PCI access mode"
1680 depends on X86_32 && PCI
1683 On PCI systems, the BIOS can be used to detect the PCI devices and
1684 determine their configuration. However, some old PCI motherboards
1685 have BIOS bugs and may crash if this is done. Also, some embedded
1686 PCI-based systems don't have any BIOS at all. Linux can also try to
1687 detect the PCI hardware directly without using the BIOS.
1689 With this option, you can specify how Linux should detect the
1690 PCI devices. If you choose "BIOS", the BIOS will be used,
1691 if you choose "Direct", the BIOS won't be used, and if you
1692 choose "MMConfig", then PCI Express MMCONFIG will be used.
1693 If you choose "Any", the kernel will try MMCONFIG, then the
1694 direct access method and falls back to the BIOS if that doesn't
1695 work. If unsure, go with the default, which is "Any".
1700 config PCI_GOMMCONFIG
1717 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1719 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1722 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1726 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1730 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1737 bool "Support mmconfig PCI config space access"
1738 depends on X86_64 && PCI && ACPI
1741 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1742 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1744 DMA remapping (DMAR) devices support enables independent address
1745 translations for Direct Memory Access (DMA) from devices.
1746 These DMA remapping devices are reported via ACPI tables
1747 and include PCI device scope covered by these DMA
1752 prompt "Support for Graphics workaround"
1755 Current Graphics drivers tend to use physical address
1756 for DMA and avoid using DMA APIs. Setting this config
1757 option permits the IOMMU driver to set a unity map for
1758 all the OS-visible memory. Hence the driver can continue
1759 to use physical addresses for DMA.
1761 config DMAR_FLOPPY_WA
1765 Floppy disk drivers are know to bypass DMA API calls
1766 thereby failing to work when IOMMU is enabled. This
1767 workaround will setup a 1:1 mapping for the first
1768 16M to make floppy (an ISA device) work.
1771 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1772 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1774 Supports Interrupt remapping for IO-APIC and MSI devices.
1775 To use x2apic mode in the CPU's which support x2APIC enhancements or
1776 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1778 source "drivers/pci/pcie/Kconfig"
1780 source "drivers/pci/Kconfig"
1782 # x86_64 have no ISA slots, but do have ISA-style DMA.
1790 depends on !X86_VOYAGER
1792 Find out whether you have ISA slots on your motherboard. ISA is the
1793 name of a bus system, i.e. the way the CPU talks to the other stuff
1794 inside your box. Other bus systems are PCI, EISA, MicroChannel
1795 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1796 newer boards don't support it. If you have ISA, say Y, otherwise N.
1802 The Extended Industry Standard Architecture (EISA) bus was
1803 developed as an open alternative to the IBM MicroChannel bus.
1805 The EISA bus provided some of the features of the IBM MicroChannel
1806 bus while maintaining backward compatibility with cards made for
1807 the older ISA bus. The EISA bus saw limited use between 1988 and
1808 1995 when it was made obsolete by the PCI bus.
1810 Say Y here if you are building a kernel for an EISA-based machine.
1814 source "drivers/eisa/Kconfig"
1817 bool "MCA support" if !X86_VOYAGER
1818 default y if X86_VOYAGER
1820 MicroChannel Architecture is found in some IBM PS/2 machines and
1821 laptops. It is a bus system similar to PCI or ISA. See
1822 <file:Documentation/mca.txt> (and especially the web page given
1823 there) before attempting to build an MCA bus kernel.
1825 source "drivers/mca/Kconfig"
1828 tristate "NatSemi SCx200 support"
1829 depends on !X86_VOYAGER
1831 This provides basic support for National Semiconductor's
1832 (now AMD's) Geode processors. The driver probes for the
1833 PCI-IDs of several on-chip devices, so its a good dependency
1834 for other scx200_* drivers.
1836 If compiled as a module, the driver is named scx200.
1838 config SCx200HR_TIMER
1839 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1840 depends on SCx200 && GENERIC_TIME
1843 This driver provides a clocksource built upon the on-chip
1844 27MHz high-resolution timer. Its also a workaround for
1845 NSC Geode SC-1100's buggy TSC, which loses time when the
1846 processor goes idle (as is done by the scheduler). The
1847 other workaround is idle=poll boot option.
1849 config GEODE_MFGPT_TIMER
1851 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1852 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1854 This driver provides a clock event source based on the MFGPT
1855 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1856 MFGPTs have a better resolution and max interval than the
1857 generic PIT, and are suitable for use as high-res timers.
1860 bool "One Laptop Per Child support"
1863 Add support for detecting the unique features of the OLPC
1870 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1872 source "drivers/pcmcia/Kconfig"
1874 source "drivers/pci/hotplug/Kconfig"
1879 menu "Executable file formats / Emulations"
1881 source "fs/Kconfig.binfmt"
1883 config IA32_EMULATION
1884 bool "IA32 Emulation"
1886 select COMPAT_BINFMT_ELF
1888 Include code to run 32-bit programs under a 64-bit kernel. You should
1889 likely turn this on, unless you're 100% sure that you don't have any
1890 32-bit programs left.
1893 tristate "IA32 a.out support"
1894 depends on IA32_EMULATION
1896 Support old a.out binaries in the 32bit emulation.
1900 depends on IA32_EMULATION
1902 config COMPAT_FOR_U64_ALIGNMENT
1906 config SYSVIPC_COMPAT
1908 depends on COMPAT && SYSVIPC
1913 config HAVE_ATOMIC_IOMAP
1917 source "net/Kconfig"
1919 source "drivers/Kconfig"
1921 source "drivers/firmware/Kconfig"
1925 source "arch/x86/Kconfig.debug"
1927 source "security/Kconfig"
1929 source "crypto/Kconfig"
1931 source "arch/x86/kvm/Kconfig"
1933 source "lib/Kconfig"
projects / linux-2.6 / blob