2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
22 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IOREMAP_PROT
27 select ARCH_WANT_OPTIONAL_GPIOLIB
28 select HAVE_KRETPROBES
29 select HAVE_DYNAMIC_FTRACE
31 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
32 select HAVE_ARCH_KGDB if !X86_VOYAGER
33 select HAVE_ARCH_TRACEHOOK
34 select HAVE_GENERIC_DMA_COHERENT if X86_32
35 select HAVE_EFFICIENT_UNALIGNED_ACCESS
39 default "arch/x86/configs/i386_defconfig" if X86_32
40 default "arch/x86/configs/x86_64_defconfig" if X86_64
45 config GENERIC_CMOS_UPDATE
48 config CLOCKSOURCE_WATCHDOG
51 config GENERIC_CLOCKEVENTS
54 config GENERIC_CLOCKEVENTS_BROADCAST
56 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
58 config LOCKDEP_SUPPORT
61 config STACKTRACE_SUPPORT
64 config HAVE_LATENCYTOP_SUPPORT
67 config FAST_CMPXCHG_LOCAL
80 config GENERIC_ISA_DMA
90 config GENERIC_HWEIGHT
96 config ARCH_MAY_HAVE_PC_FDC
99 config RWSEM_GENERIC_SPINLOCK
102 config RWSEM_XCHGADD_ALGORITHM
105 config ARCH_HAS_CPU_IDLE_WAIT
108 config GENERIC_CALIBRATE_DELAY
111 config GENERIC_TIME_VSYSCALL
115 config ARCH_HAS_CPU_RELAX
118 config ARCH_HAS_CACHE_LINE_SIZE
121 config HAVE_SETUP_PER_CPU_AREA
122 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
124 config HAVE_CPUMASK_OF_CPU_MAP
127 config ARCH_HIBERNATION_POSSIBLE
129 depends on !SMP || !X86_VOYAGER
131 config ARCH_SUSPEND_POSSIBLE
133 depends on !X86_VOYAGER
139 config ARCH_POPULATES_NODE_MAP
146 config ARCH_SUPPORTS_OPTIMIZED_INLINING
149 # Use the generic interrupt handling code in kernel/irq/:
150 config GENERIC_HARDIRQS
154 config GENERIC_IRQ_PROBE
158 config GENERIC_PENDING_IRQ
160 depends on GENERIC_HARDIRQS && SMP
165 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
166 select USE_GENERIC_SMP_HELPERS
171 depends on X86_32 && SMP
175 depends on X86_64 && SMP
180 depends on (X86_32 && !X86_VOYAGER) || X86_64
183 config X86_BIOS_REBOOT
185 depends on !X86_VOYAGER
188 config X86_TRAMPOLINE
190 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
195 source "init/Kconfig"
196 source "kernel/Kconfig.freezer"
198 menu "Processor type and features"
200 source "kernel/time/Kconfig"
203 bool "Symmetric multi-processing support"
205 This enables support for systems with more than one CPU. If you have
206 a system with only one CPU, like most personal computers, say N. If
207 you have a system with more than one CPU, say Y.
209 If you say N here, the kernel will run on single and multiprocessor
210 machines, but will use only one CPU of a multiprocessor machine. If
211 you say Y here, the kernel will run on many, but not all,
212 singleprocessor machines. On a singleprocessor machine, the kernel
213 will run faster if you say N here.
215 Note that if you say Y here and choose architecture "586" or
216 "Pentium" under "Processor family", the kernel will not work on 486
217 architectures. Similarly, multiprocessor kernels for the "PPro"
218 architecture may not work on all Pentium based boards.
220 People using multiprocessor machines who say Y here should also say
221 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
222 Management" code will be disabled if you say Y here.
224 See also <file:Documentation/i386/IO-APIC.txt>,
225 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
226 <http://www.tldp.org/docs.html#howto>.
228 If you don't know what to do here, say N.
230 config X86_FIND_SMP_CONFIG
232 depends on X86_MPPARSE || X86_VOYAGER
237 bool "Enable MPS table"
238 depends on X86_LOCAL_APIC
240 For old smp systems that do not have proper acpi support. Newer systems
241 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
247 depends on X86_LOCAL_APIC
251 prompt "Subarchitecture Type"
257 Choose this option if your computer is a standard PC or compatible.
263 Select this for an AMD Elan processor.
265 Do not use this option for K6/Athlon/Opteron processors!
267 If unsure, choose "PC-compatible" instead.
271 depends on X86_32 && (SMP || BROKEN) && !PCI
273 Voyager is an MCA-based 32-way capable SMP architecture proprietary
274 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
278 If you do not specifically know you have a Voyager based machine,
279 say N here, otherwise the kernel you build will not be bootable.
281 config X86_GENERICARCH
282 bool "Generic architecture"
285 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
286 subarchitectures. It is intended for a generic binary kernel.
287 if you select them all, kernel will probe it one by one. and will
293 bool "NUMAQ (IBM/Sequent)"
294 depends on SMP && X86_32 && PCI && X86_MPPARSE
297 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
298 NUMA multiquad box. This changes the way that processors are
299 bootstrapped, and uses Clustered Logical APIC addressing mode instead
300 of Flat Logical. You will need a new lynxer.elf file to flash your
301 firmware with - send email to <Martin.Bligh@us.ibm.com>.
304 bool "Summit/EXA (IBM x440)"
305 depends on X86_32 && SMP
307 This option is needed for IBM systems that use the Summit/EXA chipset.
308 In particular, it is needed for the x440.
311 bool "Support for Unisys ES7000 IA32 series"
312 depends on X86_32 && SMP
314 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
315 supposed to run on an IA32-based Unisys ES7000 system.
318 bool "Support for big SMP systems with more than 8 CPUs"
319 depends on X86_32 && SMP
321 This option is needed for the systems that have more than 8 CPUs
322 and if the system is not of any sub-arch type above.
327 bool "Support for ScaleMP vSMP"
329 depends on X86_64 && PCI
331 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
332 supposed to run on these EM64T-based machines. Only choose this option
333 if you have one of these machines.
338 bool "SGI 320/540 (Visual Workstation)"
339 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
341 The SGI Visual Workstation series is an IA32-based workstation
342 based on SGI systems chips with some legacy PC hardware attached.
344 Say Y here to create a kernel to run on the SGI 320 or 540.
346 A kernel compiled for the Visual Workstation will run on general
347 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
350 bool "RDC R-321x SoC"
353 select X86_REBOOTFIXUPS
355 This option is needed for RDC R-321x system-on-chip, also known
357 If you don't have one of these chips, you should say N here.
359 config SCHED_NO_NO_OMIT_FRAME_POINTER
361 prompt "Single-depth WCHAN output"
364 Calculate simpler /proc/<PID>/wchan values. If this option
365 is disabled then wchan values will recurse back to the
366 caller function. This provides more accurate wchan values,
367 at the expense of slightly more scheduling overhead.
369 If in doubt, say "Y".
371 menuconfig PARAVIRT_GUEST
372 bool "Paravirtualized guest support"
374 Say Y here to get to see options related to running Linux under
375 various hypervisors. This option alone does not add any kernel code.
377 If you say N, all options in this submenu will be skipped and disabled.
381 source "arch/x86/xen/Kconfig"
384 bool "VMI Guest support"
387 depends on !X86_VOYAGER
389 VMI provides a paravirtualized interface to the VMware ESX server
390 (it could be used by other hypervisors in theory too, but is not
391 at the moment), by linking the kernel to a GPL-ed ROM module
392 provided by the hypervisor.
395 bool "KVM paravirtualized clock"
397 select PARAVIRT_CLOCK
398 depends on !X86_VOYAGER
400 Turning on this option will allow you to run a paravirtualized clock
401 when running over the KVM hypervisor. Instead of relying on a PIT
402 (or probably other) emulation by the underlying device model, the host
403 provides the guest with timing infrastructure such as time of day, and
407 bool "KVM Guest support"
409 depends on !X86_VOYAGER
411 This option enables various optimizations for running under the KVM
414 source "arch/x86/lguest/Kconfig"
417 bool "Enable paravirtualization code"
418 depends on !X86_VOYAGER
420 This changes the kernel so it can modify itself when it is run
421 under a hypervisor, potentially improving performance significantly
422 over full virtualization. However, when run without a hypervisor
423 the kernel is theoretically slower and slightly larger.
425 config PARAVIRT_CLOCK
431 config PARAVIRT_DEBUG
432 bool "paravirt-ops debugging"
433 depends on PARAVIRT && DEBUG_KERNEL
435 Enable to debug paravirt_ops internals. Specifically, BUG if
436 a paravirt_op is missing when it is called.
441 This option adds a kernel parameter 'memtest', which allows memtest
443 memtest=0, mean disabled; -- default
444 memtest=1, mean do 1 test pattern;
446 memtest=4, mean do 4 test patterns.
447 If you are unsure how to answer this question, answer N.
449 config X86_SUMMIT_NUMA
451 depends on X86_32 && NUMA && X86_GENERICARCH
453 config X86_CYCLONE_TIMER
455 depends on X86_GENERICARCH
457 config ES7000_CLUSTERED_APIC
459 depends on SMP && X86_ES7000 && MPENTIUMIII
461 source "arch/x86/Kconfig.cpu"
465 prompt "HPET Timer Support" if X86_32
467 Use the IA-PC HPET (High Precision Event Timer) to manage
468 time in preference to the PIT and RTC, if a HPET is
470 HPET is the next generation timer replacing legacy 8254s.
471 The HPET provides a stable time base on SMP
472 systems, unlike the TSC, but it is more expensive to access,
473 as it is off-chip. You can find the HPET spec at
474 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
476 You can safely choose Y here. However, HPET will only be
477 activated if the platform and the BIOS support this feature.
478 Otherwise the 8254 will be used for timing services.
480 Choose N to continue using the legacy 8254 timer.
482 config HPET_EMULATE_RTC
484 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
486 # Mark as embedded because too many people got it wrong.
487 # The code disables itself when not needed.
490 bool "Enable DMI scanning" if EMBEDDED
492 Enabled scanning of DMI to identify machine quirks. Say Y
493 here unless you have verified that your setup is not
494 affected by entries in the DMI blacklist. Required by PNP
498 bool "GART IOMMU support" if EMBEDDED
502 depends on X86_64 && PCI
504 Support for full DMA access of devices with 32bit memory access only
505 on systems with more than 3GB. This is usually needed for USB,
506 sound, many IDE/SATA chipsets and some other devices.
507 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
508 based hardware IOMMU and a software bounce buffer based IOMMU used
509 on Intel systems and as fallback.
510 The code is only active when needed (enough memory and limited
511 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
515 bool "IBM Calgary IOMMU support"
517 depends on X86_64 && PCI && EXPERIMENTAL
519 Support for hardware IOMMUs in IBM's xSeries x366 and x460
520 systems. Needed to run systems with more than 3GB of memory
521 properly with 32-bit PCI devices that do not support DAC
522 (Double Address Cycle). Calgary also supports bus level
523 isolation, where all DMAs pass through the IOMMU. This
524 prevents them from going anywhere except their intended
525 destination. This catches hard-to-find kernel bugs and
526 mis-behaving drivers and devices that do not use the DMA-API
527 properly to set up their DMA buffers. The IOMMU can be
528 turned off at boot time with the iommu=off parameter.
529 Normally the kernel will make the right choice by itself.
532 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
534 prompt "Should Calgary be enabled by default?"
535 depends on CALGARY_IOMMU
537 Should Calgary be enabled by default? if you choose 'y', Calgary
538 will be used (if it exists). If you choose 'n', Calgary will not be
539 used even if it exists. If you choose 'n' and would like to use
540 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
544 bool "AMD IOMMU support"
547 depends on X86_64 && PCI && ACPI
549 With this option you can enable support for AMD IOMMU hardware in
550 your system. An IOMMU is a hardware component which provides
551 remapping of DMA memory accesses from devices. With an AMD IOMMU you
552 can isolate the the DMA memory of different devices and protect the
553 system from misbehaving device drivers or hardware.
555 You can find out if your system has an AMD IOMMU if you look into
556 your BIOS for an option to enable it or if you have an IVRS ACPI
559 # need this always selected by IOMMU for the VIA workaround
563 Support for software bounce buffers used on x86-64 systems
564 which don't have a hardware IOMMU (e.g. the current generation
565 of Intel's x86-64 CPUs). Using this PCI devices which can only
566 access 32-bits of memory can be used on systems with more than
567 3 GB of memory. If unsure, say Y.
570 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
573 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
574 depends on X86_64 && SMP && BROKEN
577 Configure maximum number of CPUS and NUMA Nodes for this architecture.
581 int "Maximum number of CPUs (2-512)" if !MAXSMP
584 default "4096" if MAXSMP
585 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
588 This allows you to specify the maximum number of CPUs which this
589 kernel will support. The maximum supported value is 512 and the
590 minimum value which makes sense is 2.
592 This is purely to save memory - each supported CPU adds
593 approximately eight kilobytes to the kernel image.
596 bool "SMT (Hyperthreading) scheduler support"
599 SMT scheduler support improves the CPU scheduler's decision making
600 when dealing with Intel Pentium 4 chips with HyperThreading at a
601 cost of slightly increased overhead in some places. If unsure say
606 prompt "Multi-core scheduler support"
609 Multi-core scheduler support improves the CPU scheduler's decision
610 making when dealing with multi-core CPU chips at a cost of slightly
611 increased overhead in some places. If unsure say N here.
613 source "kernel/Kconfig.preempt"
616 bool "Local APIC support on uniprocessors"
617 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
619 A local APIC (Advanced Programmable Interrupt Controller) is an
620 integrated interrupt controller in the CPU. If you have a single-CPU
621 system which has a processor with a local APIC, you can say Y here to
622 enable and use it. If you say Y here even though your machine doesn't
623 have a local APIC, then the kernel will still run with no slowdown at
624 all. The local APIC supports CPU-generated self-interrupts (timer,
625 performance counters), and the NMI watchdog which detects hard
629 bool "IO-APIC support on uniprocessors"
630 depends on X86_UP_APIC
632 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
633 SMP-capable replacement for PC-style interrupt controllers. Most
634 SMP systems and many recent uniprocessor systems have one.
636 If you have a single-CPU system with an IO-APIC, you can say Y here
637 to use it. If you say Y here even though your machine doesn't have
638 an IO-APIC, then the kernel will still run with no slowdown at all.
640 config X86_LOCAL_APIC
642 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
646 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
648 config X86_VISWS_APIC
650 depends on X86_32 && X86_VISWS
653 bool "Machine Check Exception"
654 depends on !X86_VOYAGER
656 Machine Check Exception support allows the processor to notify the
657 kernel if it detects a problem (e.g. overheating, component failure).
658 The action the kernel takes depends on the severity of the problem,
659 ranging from a warning message on the console, to halting the machine.
660 Your processor must be a Pentium or newer to support this - check the
661 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
662 have a design flaw which leads to false MCE events - hence MCE is
663 disabled on all P5 processors, unless explicitly enabled with "mce"
664 as a boot argument. Similarly, if MCE is built in and creates a
665 problem on some new non-standard machine, you can boot with "nomce"
666 to disable it. MCE support simply ignores non-MCE processors like
667 the 386 and 486, so nearly everyone can say Y here.
671 prompt "Intel MCE features"
672 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
674 Additional support for intel specific MCE features such as
679 prompt "AMD MCE features"
680 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
682 Additional support for AMD specific MCE features such as
683 the DRAM Error Threshold.
685 config X86_MCE_NONFATAL
686 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
687 depends on X86_32 && X86_MCE
689 Enabling this feature starts a timer that triggers every 5 seconds which
690 will look at the machine check registers to see if anything happened.
691 Non-fatal problems automatically get corrected (but still logged).
692 Disable this if you don't want to see these messages.
693 Seeing the messages this option prints out may be indicative of dying
694 or out-of-spec (ie, overclocked) hardware.
695 This option only does something on certain CPUs.
696 (AMD Athlon/Duron and Intel Pentium 4)
698 config X86_MCE_P4THERMAL
699 bool "check for P4 thermal throttling interrupt."
700 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
702 Enabling this feature will cause a message to be printed when the P4
703 enters thermal throttling.
706 bool "Enable VM86 support" if EMBEDDED
710 This option is required by programs like DOSEMU to run 16-bit legacy
711 code on X86 processors. It also may be needed by software like
712 XFree86 to initialize some video cards via BIOS. Disabling this
713 option saves about 6k.
716 tristate "Toshiba Laptop support"
719 This adds a driver to safely access the System Management Mode of
720 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
721 not work on models with a Phoenix BIOS. The System Management Mode
722 is used to set the BIOS and power saving options on Toshiba portables.
724 For information on utilities to make use of this driver see the
725 Toshiba Linux utilities web site at:
726 <http://www.buzzard.org.uk/toshiba/>.
728 Say Y if you intend to run this kernel on a Toshiba portable.
732 tristate "Dell laptop support"
734 This adds a driver to safely access the System Management Mode
735 of the CPU on the Dell Inspiron 8000. The System Management Mode
736 is used to read cpu temperature and cooling fan status and to
737 control the fans on the I8K portables.
739 This driver has been tested only on the Inspiron 8000 but it may
740 also work with other Dell laptops. You can force loading on other
741 models by passing the parameter `force=1' to the module. Use at
744 For information on utilities to make use of this driver see the
745 I8K Linux utilities web site at:
746 <http://people.debian.org/~dz/i8k/>
748 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
751 config X86_REBOOTFIXUPS
752 bool "Enable X86 board specific fixups for reboot"
755 This enables chipset and/or board specific fixups to be done
756 in order to get reboot to work correctly. This is only needed on
757 some combinations of hardware and BIOS. The symptom, for which
758 this config is intended, is when reboot ends with a stalled/hung
761 Currently, the only fixup is for the Geode machines using
762 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
764 Say Y if you want to enable the fixup. Currently, it's safe to
765 enable this option even if you don't need it.
769 tristate "/dev/cpu/microcode - microcode support"
772 If you say Y here, you will be able to update the microcode on
773 certain Intel and AMD processors. The Intel support is for the
774 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
775 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
776 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
777 You will obviously need the actual microcode binary data itself
778 which is not shipped with the Linux kernel.
780 This option selects the general module only, you need to select
781 at least one vendor specific module as well.
783 To compile this driver as a module, choose M here: the
784 module will be called microcode.
786 config MICROCODE_INTEL
787 bool "Intel microcode patch loading support"
792 This options enables microcode patch loading support for Intel
795 For latest news and information on obtaining all the required
796 Intel ingredients for this driver, check:
797 <http://www.urbanmyth.org/microcode/>.
800 bool "AMD microcode patch loading support"
804 If you select this option, microcode patch loading support for AMD
805 processors will be enabled.
807 config MICROCODE_OLD_INTERFACE
812 tristate "/dev/cpu/*/msr - Model-specific register support"
814 This device gives privileged processes access to the x86
815 Model-Specific Registers (MSRs). It is a character device with
816 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
817 MSR accesses are directed to a specific CPU on multi-processor
821 tristate "/dev/cpu/*/cpuid - CPU information support"
823 This device gives processes access to the x86 CPUID instruction to
824 be executed on a specific processor. It is a character device
825 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
829 prompt "High Memory Support"
830 default HIGHMEM4G if !X86_NUMAQ
831 default HIGHMEM64G if X86_NUMAQ
836 depends on !X86_NUMAQ
838 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
839 However, the address space of 32-bit x86 processors is only 4
840 Gigabytes large. That means that, if you have a large amount of
841 physical memory, not all of it can be "permanently mapped" by the
842 kernel. The physical memory that's not permanently mapped is called
845 If you are compiling a kernel which will never run on a machine with
846 more than 1 Gigabyte total physical RAM, answer "off" here (default
847 choice and suitable for most users). This will result in a "3GB/1GB"
848 split: 3GB are mapped so that each process sees a 3GB virtual memory
849 space and the remaining part of the 4GB virtual memory space is used
850 by the kernel to permanently map as much physical memory as
853 If the machine has between 1 and 4 Gigabytes physical RAM, then
856 If more than 4 Gigabytes is used then answer "64GB" here. This
857 selection turns Intel PAE (Physical Address Extension) mode on.
858 PAE implements 3-level paging on IA32 processors. PAE is fully
859 supported by Linux, PAE mode is implemented on all recent Intel
860 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
861 then the kernel will not boot on CPUs that don't support PAE!
863 The actual amount of total physical memory will either be
864 auto detected or can be forced by using a kernel command line option
865 such as "mem=256M". (Try "man bootparam" or see the documentation of
866 your boot loader (lilo or loadlin) about how to pass options to the
867 kernel at boot time.)
869 If unsure, say "off".
873 depends on !X86_NUMAQ
875 Select this if you have a 32-bit processor and between 1 and 4
876 gigabytes of physical RAM.
880 depends on !M386 && !M486
883 Select this if you have a 32-bit processor and more than 4
884 gigabytes of physical RAM.
889 depends on EXPERIMENTAL
890 prompt "Memory split" if EMBEDDED
894 Select the desired split between kernel and user memory.
896 If the address range available to the kernel is less than the
897 physical memory installed, the remaining memory will be available
898 as "high memory". Accessing high memory is a little more costly
899 than low memory, as it needs to be mapped into the kernel first.
900 Note that increasing the kernel address space limits the range
901 available to user programs, making the address space there
902 tighter. Selecting anything other than the default 3G/1G split
903 will also likely make your kernel incompatible with binary-only
906 If you are not absolutely sure what you are doing, leave this
910 bool "3G/1G user/kernel split"
911 config VMSPLIT_3G_OPT
913 bool "3G/1G user/kernel split (for full 1G low memory)"
915 bool "2G/2G user/kernel split"
916 config VMSPLIT_2G_OPT
918 bool "2G/2G user/kernel split (for full 2G low memory)"
920 bool "1G/3G user/kernel split"
925 default 0xB0000000 if VMSPLIT_3G_OPT
926 default 0x80000000 if VMSPLIT_2G
927 default 0x78000000 if VMSPLIT_2G_OPT
928 default 0x40000000 if VMSPLIT_1G
934 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
937 bool "PAE (Physical Address Extension) Support"
938 depends on X86_32 && !HIGHMEM4G
940 PAE is required for NX support, and furthermore enables
941 larger swapspace support for non-overcommit purposes. It
942 has the cost of more pagetable lookup overhead, and also
943 consumes more pagetable space per process.
945 config ARCH_PHYS_ADDR_T_64BIT
946 def_bool X86_64 || X86_PAE
948 # Common NUMA Features
950 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
952 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
954 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
956 Enable NUMA (Non Uniform Memory Access) support.
957 The kernel will try to allocate memory used by a CPU on the
958 local memory controller of the CPU and add some more
959 NUMA awareness to the kernel.
961 For 32-bit this is currently highly experimental and should be only
962 used for kernel development. It might also cause boot failures.
963 For 64-bit this is recommended on all multiprocessor Opteron systems.
964 If the system is EM64T, you should say N unless your system is
967 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
968 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
972 prompt "Old style AMD Opteron NUMA detection"
973 depends on X86_64 && NUMA && PCI
975 Enable K8 NUMA node topology detection. You should say Y here if
976 you have a multi processor AMD K8 system. This uses an old
977 method to read the NUMA configuration directly from the builtin
978 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
979 instead, which also takes priority if both are compiled in.
981 config X86_64_ACPI_NUMA
983 prompt "ACPI NUMA detection"
984 depends on X86_64 && NUMA && ACPI && PCI
987 Enable ACPI SRAT based node topology detection.
989 # Some NUMA nodes have memory ranges that span
990 # other nodes. Even though a pfn is valid and
991 # between a node's start and end pfns, it may not
992 # reside on that node. See memmap_init_zone()
994 config NODES_SPAN_OTHER_NODES
996 depends on X86_64_ACPI_NUMA
999 bool "NUMA emulation"
1000 depends on X86_64 && NUMA
1002 Enable NUMA emulation. A flat machine will be split
1003 into virtual nodes when booted with "numa=fake=N", where N is the
1004 number of nodes. This is only useful for debugging.
1007 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1009 default "9" if MAXSMP
1010 default "6" if X86_64
1011 default "4" if X86_NUMAQ
1013 depends on NEED_MULTIPLE_NODES
1015 Specify the maximum number of NUMA Nodes available on the target
1016 system. Increases memory reserved to accomodate various tables.
1018 config HAVE_ARCH_BOOTMEM_NODE
1020 depends on X86_32 && NUMA
1022 config ARCH_HAVE_MEMORY_PRESENT
1024 depends on X86_32 && DISCONTIGMEM
1026 config NEED_NODE_MEMMAP_SIZE
1028 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1030 config HAVE_ARCH_ALLOC_REMAP
1032 depends on X86_32 && NUMA
1034 config ARCH_FLATMEM_ENABLE
1036 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1038 config ARCH_DISCONTIGMEM_ENABLE
1040 depends on NUMA && X86_32
1042 config ARCH_DISCONTIGMEM_DEFAULT
1044 depends on NUMA && X86_32
1046 config ARCH_SPARSEMEM_DEFAULT
1050 config ARCH_SPARSEMEM_ENABLE
1052 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1053 select SPARSEMEM_STATIC if X86_32
1054 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1056 config ARCH_SELECT_MEMORY_MODEL
1058 depends on ARCH_SPARSEMEM_ENABLE
1060 config ARCH_MEMORY_PROBE
1062 depends on MEMORY_HOTPLUG
1067 bool "Allocate 3rd-level pagetables from highmem"
1068 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1070 The VM uses one page table entry for each page of physical memory.
1071 For systems with a lot of RAM, this can be wasteful of precious
1072 low memory. Setting this option will put user-space page table
1073 entries in high memory.
1075 config X86_CHECK_BIOS_CORRUPTION
1076 bool "Check for low memory corruption"
1078 Periodically check for memory corruption in low memory, which
1079 is suspected to be caused by BIOS. Even when enabled in the
1080 configuration, it is disabled at runtime. Enable it by
1081 setting "memory_corruption_check=1" on the kernel command
1082 line. By default it scans the low 64k of memory every 60
1083 seconds; see the memory_corruption_check_size and
1084 memory_corruption_check_period parameters in
1085 Documentation/kernel-parameters.txt to adjust this.
1087 When enabled with the default parameters, this option has
1088 almost no overhead, as it reserves a relatively small amount
1089 of memory and scans it infrequently. It both detects corruption
1090 and prevents it from affecting the running system.
1092 It is, however, intended as a diagnostic tool; if repeatable
1093 BIOS-originated corruption always affects the same memory,
1094 you can use memmap= to prevent the kernel from using that
1097 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1098 bool "Set the default setting of memory_corruption_check"
1099 depends on X86_CHECK_BIOS_CORRUPTION
1102 Set whether the default state of memory_corruption_check is
1105 config X86_RESERVE_LOW_64K
1106 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1109 Reserve the first 64K of physical RAM on BIOSes that are known
1110 to potentially corrupt that memory range. A numbers of BIOSes are
1111 known to utilize this area during suspend/resume, so it must not
1112 be used by the kernel.
1114 Set this to N if you are absolutely sure that you trust the BIOS
1115 to get all its memory reservations and usages right.
1117 If you have doubts about the BIOS (e.g. suspend/resume does not
1118 work or there's kernel crashes after certain hardware hotplug
1119 events) and it's not AMI or Phoenix, then you might want to enable
1120 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1121 corruption patterns.
1125 config MATH_EMULATION
1127 prompt "Math emulation" if X86_32
1129 Linux can emulate a math coprocessor (used for floating point
1130 operations) if you don't have one. 486DX and Pentium processors have
1131 a math coprocessor built in, 486SX and 386 do not, unless you added
1132 a 487DX or 387, respectively. (The messages during boot time can
1133 give you some hints here ["man dmesg"].) Everyone needs either a
1134 coprocessor or this emulation.
1136 If you don't have a math coprocessor, you need to say Y here; if you
1137 say Y here even though you have a coprocessor, the coprocessor will
1138 be used nevertheless. (This behavior can be changed with the kernel
1139 command line option "no387", which comes handy if your coprocessor
1140 is broken. Try "man bootparam" or see the documentation of your boot
1141 loader (lilo or loadlin) about how to pass options to the kernel at
1142 boot time.) This means that it is a good idea to say Y here if you
1143 intend to use this kernel on different machines.
1145 More information about the internals of the Linux math coprocessor
1146 emulation can be found in <file:arch/x86/math-emu/README>.
1148 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1149 kernel, it won't hurt.
1152 bool "MTRR (Memory Type Range Register) support"
1154 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1155 the Memory Type Range Registers (MTRRs) may be used to control
1156 processor access to memory ranges. This is most useful if you have
1157 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1158 allows bus write transfers to be combined into a larger transfer
1159 before bursting over the PCI/AGP bus. This can increase performance
1160 of image write operations 2.5 times or more. Saying Y here creates a
1161 /proc/mtrr file which may be used to manipulate your processor's
1162 MTRRs. Typically the X server should use this.
1164 This code has a reasonably generic interface so that similar
1165 control registers on other processors can be easily supported
1168 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1169 Registers (ARRs) which provide a similar functionality to MTRRs. For
1170 these, the ARRs are used to emulate the MTRRs.
1171 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1172 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1173 write-combining. All of these processors are supported by this code
1174 and it makes sense to say Y here if you have one of them.
1176 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1177 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1178 can lead to all sorts of problems, so it's good to say Y here.
1180 You can safely say Y even if your machine doesn't have MTRRs, you'll
1181 just add about 9 KB to your kernel.
1183 See <file:Documentation/x86/mtrr.txt> for more information.
1185 config MTRR_SANITIZER
1187 prompt "MTRR cleanup support"
1190 Convert MTRR layout from continuous to discrete, so X drivers can
1191 add writeback entries.
1193 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1194 The largest mtrr entry size for a continous block can be set with
1199 config MTRR_SANITIZER_ENABLE_DEFAULT
1200 int "MTRR cleanup enable value (0-1)"
1203 depends on MTRR_SANITIZER
1205 Enable mtrr cleanup default value
1207 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1208 int "MTRR cleanup spare reg num (0-7)"
1211 depends on MTRR_SANITIZER
1213 mtrr cleanup spare entries default, it can be changed via
1214 mtrr_spare_reg_nr=N on the kernel command line.
1218 prompt "x86 PAT support"
1221 Use PAT attributes to setup page level cache control.
1223 PATs are the modern equivalents of MTRRs and are much more
1224 flexible than MTRRs.
1226 Say N here if you see bootup problems (boot crash, boot hang,
1227 spontaneous reboots) or a non-working video driver.
1232 bool "EFI runtime service support"
1235 This enables the kernel to use EFI runtime services that are
1236 available (such as the EFI variable services).
1238 This option is only useful on systems that have EFI firmware.
1239 In addition, you should use the latest ELILO loader available
1240 at <http://elilo.sourceforge.net> in order to take advantage
1241 of EFI runtime services. However, even with this option, the
1242 resultant kernel should continue to boot on existing non-EFI
1247 prompt "Enable seccomp to safely compute untrusted bytecode"
1249 This kernel feature is useful for number crunching applications
1250 that may need to compute untrusted bytecode during their
1251 execution. By using pipes or other transports made available to
1252 the process as file descriptors supporting the read/write
1253 syscalls, it's possible to isolate those applications in
1254 their own address space using seccomp. Once seccomp is
1255 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1256 and the task is only allowed to execute a few safe syscalls
1257 defined by each seccomp mode.
1259 If unsure, say Y. Only embedded should say N here.
1261 config CC_STACKPROTECTOR
1262 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1263 depends on X86_64 && EXPERIMENTAL && BROKEN
1265 This option turns on the -fstack-protector GCC feature. This
1266 feature puts, at the beginning of critical functions, a canary
1267 value on the stack just before the return address, and validates
1268 the value just before actually returning. Stack based buffer
1269 overflows (that need to overwrite this return address) now also
1270 overwrite the canary, which gets detected and the attack is then
1271 neutralized via a kernel panic.
1273 This feature requires gcc version 4.2 or above, or a distribution
1274 gcc with the feature backported. Older versions are automatically
1275 detected and for those versions, this configuration option is ignored.
1277 config CC_STACKPROTECTOR_ALL
1278 bool "Use stack-protector for all functions"
1279 depends on CC_STACKPROTECTOR
1281 Normally, GCC only inserts the canary value protection for
1282 functions that use large-ish on-stack buffers. By enabling
1283 this option, GCC will be asked to do this for ALL functions.
1285 source kernel/Kconfig.hz
1288 bool "kexec system call"
1289 depends on X86_BIOS_REBOOT
1291 kexec is a system call that implements the ability to shutdown your
1292 current kernel, and to start another kernel. It is like a reboot
1293 but it is independent of the system firmware. And like a reboot
1294 you can start any kernel with it, not just Linux.
1296 The name comes from the similarity to the exec system call.
1298 It is an ongoing process to be certain the hardware in a machine
1299 is properly shutdown, so do not be surprised if this code does not
1300 initially work for you. It may help to enable device hotplugging
1301 support. As of this writing the exact hardware interface is
1302 strongly in flux, so no good recommendation can be made.
1305 bool "kernel crash dumps"
1306 depends on X86_64 || (X86_32 && HIGHMEM)
1308 Generate crash dump after being started by kexec.
1309 This should be normally only set in special crash dump kernels
1310 which are loaded in the main kernel with kexec-tools into
1311 a specially reserved region and then later executed after
1312 a crash by kdump/kexec. The crash dump kernel must be compiled
1313 to a memory address not used by the main kernel or BIOS using
1314 PHYSICAL_START, or it must be built as a relocatable image
1315 (CONFIG_RELOCATABLE=y).
1316 For more details see Documentation/kdump/kdump.txt
1319 bool "kexec jump (EXPERIMENTAL)"
1320 depends on EXPERIMENTAL
1321 depends on KEXEC && HIBERNATION && X86_32
1323 Jump between original kernel and kexeced kernel and invoke
1324 code in physical address mode via KEXEC
1326 config PHYSICAL_START
1327 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1328 default "0x1000000" if X86_NUMAQ
1329 default "0x200000" if X86_64
1332 This gives the physical address where the kernel is loaded.
1334 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1335 bzImage will decompress itself to above physical address and
1336 run from there. Otherwise, bzImage will run from the address where
1337 it has been loaded by the boot loader and will ignore above physical
1340 In normal kdump cases one does not have to set/change this option
1341 as now bzImage can be compiled as a completely relocatable image
1342 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1343 address. This option is mainly useful for the folks who don't want
1344 to use a bzImage for capturing the crash dump and want to use a
1345 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1346 to be specifically compiled to run from a specific memory area
1347 (normally a reserved region) and this option comes handy.
1349 So if you are using bzImage for capturing the crash dump, leave
1350 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1351 Otherwise if you plan to use vmlinux for capturing the crash dump
1352 change this value to start of the reserved region (Typically 16MB
1353 0x1000000). In other words, it can be set based on the "X" value as
1354 specified in the "crashkernel=YM@XM" command line boot parameter
1355 passed to the panic-ed kernel. Typically this parameter is set as
1356 crashkernel=64M@16M. Please take a look at
1357 Documentation/kdump/kdump.txt for more details about crash dumps.
1359 Usage of bzImage for capturing the crash dump is recommended as
1360 one does not have to build two kernels. Same kernel can be used
1361 as production kernel and capture kernel. Above option should have
1362 gone away after relocatable bzImage support is introduced. But it
1363 is present because there are users out there who continue to use
1364 vmlinux for dump capture. This option should go away down the
1367 Don't change this unless you know what you are doing.
1370 bool "Build a relocatable kernel (EXPERIMENTAL)"
1371 depends on EXPERIMENTAL
1373 This builds a kernel image that retains relocation information
1374 so it can be loaded someplace besides the default 1MB.
1375 The relocations tend to make the kernel binary about 10% larger,
1376 but are discarded at runtime.
1378 One use is for the kexec on panic case where the recovery kernel
1379 must live at a different physical address than the primary
1382 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1383 it has been loaded at and the compile time physical address
1384 (CONFIG_PHYSICAL_START) is ignored.
1386 config PHYSICAL_ALIGN
1388 prompt "Alignment value to which kernel should be aligned" if X86_32
1389 default "0x100000" if X86_32
1390 default "0x200000" if X86_64
1391 range 0x2000 0x400000
1393 This value puts the alignment restrictions on physical address
1394 where kernel is loaded and run from. Kernel is compiled for an
1395 address which meets above alignment restriction.
1397 If bootloader loads the kernel at a non-aligned address and
1398 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1399 address aligned to above value and run from there.
1401 If bootloader loads the kernel at a non-aligned address and
1402 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1403 load address and decompress itself to the address it has been
1404 compiled for and run from there. The address for which kernel is
1405 compiled already meets above alignment restrictions. Hence the
1406 end result is that kernel runs from a physical address meeting
1407 above alignment restrictions.
1409 Don't change this unless you know what you are doing.
1412 bool "Support for hot-pluggable CPUs"
1413 depends on SMP && HOTPLUG && !X86_VOYAGER
1415 Say Y here to allow turning CPUs off and on. CPUs can be
1416 controlled through /sys/devices/system/cpu.
1417 ( Note: power management support will enable this option
1418 automatically on SMP systems. )
1419 Say N if you want to disable CPU hotplug.
1423 prompt "Compat VDSO support"
1424 depends on X86_32 || IA32_EMULATION
1426 Map the 32-bit VDSO to the predictable old-style address too.
1428 Say N here if you are running a sufficiently recent glibc
1429 version (2.3.3 or later), to remove the high-mapped
1430 VDSO mapping and to exclusively use the randomized VDSO.
1435 bool "Built-in kernel command line"
1438 Allow for specifying boot arguments to the kernel at
1439 build time. On some systems (e.g. embedded ones), it is
1440 necessary or convenient to provide some or all of the
1441 kernel boot arguments with the kernel itself (that is,
1442 to not rely on the boot loader to provide them.)
1444 To compile command line arguments into the kernel,
1445 set this option to 'Y', then fill in the
1446 the boot arguments in CONFIG_CMDLINE.
1448 Systems with fully functional boot loaders (i.e. non-embedded)
1449 should leave this option set to 'N'.
1452 string "Built-in kernel command string"
1453 depends on CMDLINE_BOOL
1456 Enter arguments here that should be compiled into the kernel
1457 image and used at boot time. If the boot loader provides a
1458 command line at boot time, it is appended to this string to
1459 form the full kernel command line, when the system boots.
1461 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1462 change this behavior.
1464 In most cases, the command line (whether built-in or provided
1465 by the boot loader) should specify the device for the root
1468 config CMDLINE_OVERRIDE
1469 bool "Built-in command line overrides boot loader arguments"
1471 depends on CMDLINE_BOOL
1473 Set this option to 'Y' to have the kernel ignore the boot loader
1474 command line, and use ONLY the built-in command line.
1476 This is used to work around broken boot loaders. This should
1477 be set to 'N' under normal conditions.
1481 config ARCH_ENABLE_MEMORY_HOTPLUG
1483 depends on X86_64 || (X86_32 && HIGHMEM)
1485 config HAVE_ARCH_EARLY_PFN_TO_NID
1489 menu "Power management options"
1490 depends on !X86_VOYAGER
1492 config ARCH_HIBERNATION_HEADER
1494 depends on X86_64 && HIBERNATION
1496 source "kernel/power/Kconfig"
1498 source "drivers/acpi/Kconfig"
1503 depends on APM || APM_MODULE
1506 tristate "APM (Advanced Power Management) BIOS support"
1507 depends on X86_32 && PM_SLEEP
1509 APM is a BIOS specification for saving power using several different
1510 techniques. This is mostly useful for battery powered laptops with
1511 APM compliant BIOSes. If you say Y here, the system time will be
1512 reset after a RESUME operation, the /proc/apm device will provide
1513 battery status information, and user-space programs will receive
1514 notification of APM "events" (e.g. battery status change).
1516 If you select "Y" here, you can disable actual use of the APM
1517 BIOS by passing the "apm=off" option to the kernel at boot time.
1519 Note that the APM support is almost completely disabled for
1520 machines with more than one CPU.
1522 In order to use APM, you will need supporting software. For location
1523 and more information, read <file:Documentation/power/pm.txt> and the
1524 Battery Powered Linux mini-HOWTO, available from
1525 <http://www.tldp.org/docs.html#howto>.
1527 This driver does not spin down disk drives (see the hdparm(8)
1528 manpage ("man 8 hdparm") for that), and it doesn't turn off
1529 VESA-compliant "green" monitors.
1531 This driver does not support the TI 4000M TravelMate and the ACER
1532 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1533 desktop machines also don't have compliant BIOSes, and this driver
1534 may cause those machines to panic during the boot phase.
1536 Generally, if you don't have a battery in your machine, there isn't
1537 much point in using this driver and you should say N. If you get
1538 random kernel OOPSes or reboots that don't seem to be related to
1539 anything, try disabling/enabling this option (or disabling/enabling
1542 Some other things you should try when experiencing seemingly random,
1545 1) make sure that you have enough swap space and that it is
1547 2) pass the "no-hlt" option to the kernel
1548 3) switch on floating point emulation in the kernel and pass
1549 the "no387" option to the kernel
1550 4) pass the "floppy=nodma" option to the kernel
1551 5) pass the "mem=4M" option to the kernel (thereby disabling
1552 all but the first 4 MB of RAM)
1553 6) make sure that the CPU is not over clocked.
1554 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1555 8) disable the cache from your BIOS settings
1556 9) install a fan for the video card or exchange video RAM
1557 10) install a better fan for the CPU
1558 11) exchange RAM chips
1559 12) exchange the motherboard.
1561 To compile this driver as a module, choose M here: the
1562 module will be called apm.
1566 config APM_IGNORE_USER_SUSPEND
1567 bool "Ignore USER SUSPEND"
1569 This option will ignore USER SUSPEND requests. On machines with a
1570 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1571 series notebooks, it is necessary to say Y because of a BIOS bug.
1573 config APM_DO_ENABLE
1574 bool "Enable PM at boot time"
1576 Enable APM features at boot time. From page 36 of the APM BIOS
1577 specification: "When disabled, the APM BIOS does not automatically
1578 power manage devices, enter the Standby State, enter the Suspend
1579 State, or take power saving steps in response to CPU Idle calls."
1580 This driver will make CPU Idle calls when Linux is idle (unless this
1581 feature is turned off -- see "Do CPU IDLE calls", below). This
1582 should always save battery power, but more complicated APM features
1583 will be dependent on your BIOS implementation. You may need to turn
1584 this option off if your computer hangs at boot time when using APM
1585 support, or if it beeps continuously instead of suspending. Turn
1586 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1587 T400CDT. This is off by default since most machines do fine without
1591 bool "Make CPU Idle calls when idle"
1593 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1594 On some machines, this can activate improved power savings, such as
1595 a slowed CPU clock rate, when the machine is idle. These idle calls
1596 are made after the idle loop has run for some length of time (e.g.,
1597 333 mS). On some machines, this will cause a hang at boot time or
1598 whenever the CPU becomes idle. (On machines with more than one CPU,
1599 this option does nothing.)
1601 config APM_DISPLAY_BLANK
1602 bool "Enable console blanking using APM"
1604 Enable console blanking using the APM. Some laptops can use this to
1605 turn off the LCD backlight when the screen blanker of the Linux
1606 virtual console blanks the screen. Note that this is only used by
1607 the virtual console screen blanker, and won't turn off the backlight
1608 when using the X Window system. This also doesn't have anything to
1609 do with your VESA-compliant power-saving monitor. Further, this
1610 option doesn't work for all laptops -- it might not turn off your
1611 backlight at all, or it might print a lot of errors to the console,
1612 especially if you are using gpm.
1614 config APM_ALLOW_INTS
1615 bool "Allow interrupts during APM BIOS calls"
1617 Normally we disable external interrupts while we are making calls to
1618 the APM BIOS as a measure to lessen the effects of a badly behaving
1619 BIOS implementation. The BIOS should reenable interrupts if it
1620 needs to. Unfortunately, some BIOSes do not -- especially those in
1621 many of the newer IBM Thinkpads. If you experience hangs when you
1622 suspend, try setting this to Y. Otherwise, say N.
1624 config APM_REAL_MODE_POWER_OFF
1625 bool "Use real mode APM BIOS call to power off"
1627 Use real mode APM BIOS calls to switch off the computer. This is
1628 a work-around for a number of buggy BIOSes. Switch this option on if
1629 your computer crashes instead of powering off properly.
1633 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1635 source "drivers/cpuidle/Kconfig"
1640 menu "Bus options (PCI etc.)"
1645 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1647 Find out whether you have a PCI motherboard. PCI is the name of a
1648 bus system, i.e. the way the CPU talks to the other stuff inside
1649 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1650 VESA. If you have PCI, say Y, otherwise N.
1653 prompt "PCI access mode"
1654 depends on X86_32 && PCI
1657 On PCI systems, the BIOS can be used to detect the PCI devices and
1658 determine their configuration. However, some old PCI motherboards
1659 have BIOS bugs and may crash if this is done. Also, some embedded
1660 PCI-based systems don't have any BIOS at all. Linux can also try to
1661 detect the PCI hardware directly without using the BIOS.
1663 With this option, you can specify how Linux should detect the
1664 PCI devices. If you choose "BIOS", the BIOS will be used,
1665 if you choose "Direct", the BIOS won't be used, and if you
1666 choose "MMConfig", then PCI Express MMCONFIG will be used.
1667 If you choose "Any", the kernel will try MMCONFIG, then the
1668 direct access method and falls back to the BIOS if that doesn't
1669 work. If unsure, go with the default, which is "Any".
1674 config PCI_GOMMCONFIG
1691 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1693 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1696 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1700 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1704 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1711 bool "Support mmconfig PCI config space access"
1712 depends on X86_64 && PCI && ACPI
1715 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1716 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1718 DMA remapping (DMAR) devices support enables independent address
1719 translations for Direct Memory Access (DMA) from devices.
1720 These DMA remapping devices are reported via ACPI tables
1721 and include PCI device scope covered by these DMA
1726 prompt "Support for Graphics workaround"
1729 Current Graphics drivers tend to use physical address
1730 for DMA and avoid using DMA APIs. Setting this config
1731 option permits the IOMMU driver to set a unity map for
1732 all the OS-visible memory. Hence the driver can continue
1733 to use physical addresses for DMA.
1735 config DMAR_FLOPPY_WA
1739 Floppy disk drivers are know to bypass DMA API calls
1740 thereby failing to work when IOMMU is enabled. This
1741 workaround will setup a 1:1 mapping for the first
1742 16M to make floppy (an ISA device) work.
1745 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1746 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1748 Supports Interrupt remapping for IO-APIC and MSI devices.
1749 To use x2apic mode in the CPU's which support x2APIC enhancements or
1750 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1752 source "drivers/pci/pcie/Kconfig"
1754 source "drivers/pci/Kconfig"
1756 # x86_64 have no ISA slots, but do have ISA-style DMA.
1764 depends on !X86_VOYAGER
1766 Find out whether you have ISA slots on your motherboard. ISA is the
1767 name of a bus system, i.e. the way the CPU talks to the other stuff
1768 inside your box. Other bus systems are PCI, EISA, MicroChannel
1769 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1770 newer boards don't support it. If you have ISA, say Y, otherwise N.
1776 The Extended Industry Standard Architecture (EISA) bus was
1777 developed as an open alternative to the IBM MicroChannel bus.
1779 The EISA bus provided some of the features of the IBM MicroChannel
1780 bus while maintaining backward compatibility with cards made for
1781 the older ISA bus. The EISA bus saw limited use between 1988 and
1782 1995 when it was made obsolete by the PCI bus.
1784 Say Y here if you are building a kernel for an EISA-based machine.
1788 source "drivers/eisa/Kconfig"
1791 bool "MCA support" if !X86_VOYAGER
1792 default y if X86_VOYAGER
1794 MicroChannel Architecture is found in some IBM PS/2 machines and
1795 laptops. It is a bus system similar to PCI or ISA. See
1796 <file:Documentation/mca.txt> (and especially the web page given
1797 there) before attempting to build an MCA bus kernel.
1799 source "drivers/mca/Kconfig"
1802 tristate "NatSemi SCx200 support"
1803 depends on !X86_VOYAGER
1805 This provides basic support for National Semiconductor's
1806 (now AMD's) Geode processors. The driver probes for the
1807 PCI-IDs of several on-chip devices, so its a good dependency
1808 for other scx200_* drivers.
1810 If compiled as a module, the driver is named scx200.
1812 config SCx200HR_TIMER
1813 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1814 depends on SCx200 && GENERIC_TIME
1817 This driver provides a clocksource built upon the on-chip
1818 27MHz high-resolution timer. Its also a workaround for
1819 NSC Geode SC-1100's buggy TSC, which loses time when the
1820 processor goes idle (as is done by the scheduler). The
1821 other workaround is idle=poll boot option.
1823 config GEODE_MFGPT_TIMER
1825 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1826 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1828 This driver provides a clock event source based on the MFGPT
1829 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1830 MFGPTs have a better resolution and max interval than the
1831 generic PIT, and are suitable for use as high-res timers.
1834 bool "One Laptop Per Child support"
1837 Add support for detecting the unique features of the OLPC
1844 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1846 source "drivers/pcmcia/Kconfig"
1848 source "drivers/pci/hotplug/Kconfig"
1853 menu "Executable file formats / Emulations"
1855 source "fs/Kconfig.binfmt"
1857 config IA32_EMULATION
1858 bool "IA32 Emulation"
1860 select COMPAT_BINFMT_ELF
1862 Include code to run 32-bit programs under a 64-bit kernel. You should
1863 likely turn this on, unless you're 100% sure that you don't have any
1864 32-bit programs left.
1867 tristate "IA32 a.out support"
1868 depends on IA32_EMULATION
1870 Support old a.out binaries in the 32bit emulation.
1874 depends on IA32_EMULATION
1876 config COMPAT_FOR_U64_ALIGNMENT
1880 config SYSVIPC_COMPAT
1882 depends on COMPAT && SYSVIPC
1887 source "net/Kconfig"
1889 source "drivers/Kconfig"
1891 source "drivers/firmware/Kconfig"
1895 source "arch/x86/Kconfig.debug"
1897 source "security/Kconfig"
1899 source "crypto/Kconfig"
1901 source "arch/x86/kvm/Kconfig"
1903 source "lib/Kconfig"
projects / linux-2.6 / blob