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
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
43 select HAVE_DMA_API_DEBUG
44 select HAVE_KERNEL_GZIP
45 select HAVE_KERNEL_BZIP2
46 select HAVE_KERNEL_LZMA
50 default "arch/x86/configs/i386_defconfig" if X86_32
51 default "arch/x86/configs/x86_64_defconfig" if X86_64
56 config GENERIC_CMOS_UPDATE
59 config CLOCKSOURCE_WATCHDOG
62 config GENERIC_CLOCKEVENTS
65 config GENERIC_CLOCKEVENTS_BROADCAST
67 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
69 config LOCKDEP_SUPPORT
72 config STACKTRACE_SUPPORT
75 config HAVE_LATENCYTOP_SUPPORT
78 config FAST_CMPXCHG_LOCAL
91 config GENERIC_ISA_DMA
100 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
102 config GENERIC_BUG_RELATIVE_POINTERS
105 config GENERIC_HWEIGHT
111 config ARCH_MAY_HAVE_PC_FDC
114 config RWSEM_GENERIC_SPINLOCK
117 config RWSEM_XCHGADD_ALGORITHM
120 config ARCH_HAS_CPU_IDLE_WAIT
123 config GENERIC_CALIBRATE_DELAY
126 config GENERIC_TIME_VSYSCALL
130 config ARCH_HAS_CPU_RELAX
133 config ARCH_HAS_DEFAULT_IDLE
136 config ARCH_HAS_CACHE_LINE_SIZE
139 config HAVE_SETUP_PER_CPU_AREA
142 config HAVE_DYNAMIC_PER_CPU_AREA
145 config HAVE_CPUMASK_OF_CPU_MAP
148 config ARCH_HIBERNATION_POSSIBLE
151 config ARCH_SUSPEND_POSSIBLE
158 config ARCH_POPULATES_NODE_MAP
165 config ARCH_SUPPORTS_OPTIMIZED_INLINING
168 # Use the generic interrupt handling code in kernel/irq/:
169 config GENERIC_HARDIRQS
173 config GENERIC_HARDIRQS_NO__DO_IRQ
176 config GENERIC_IRQ_PROBE
180 config GENERIC_PENDING_IRQ
182 depends on GENERIC_HARDIRQS && SMP
185 config USE_GENERIC_SMP_HELPERS
191 depends on X86_32 && SMP
195 depends on X86_64 && SMP
202 config X86_TRAMPOLINE
204 depends on SMP || (64BIT && ACPI_SLEEP)
207 config X86_32_LAZY_GS
209 depends on X86_32 && !CC_STACKPROTECTOR
213 source "init/Kconfig"
214 source "kernel/Kconfig.freezer"
216 menu "Processor type and features"
218 source "kernel/time/Kconfig"
221 bool "Symmetric multi-processing support"
223 This enables support for systems with more than one CPU. If you have
224 a system with only one CPU, like most personal computers, say N. If
225 you have a system with more than one CPU, say Y.
227 If you say N here, the kernel will run on single and multiprocessor
228 machines, but will use only one CPU of a multiprocessor machine. If
229 you say Y here, the kernel will run on many, but not all,
230 singleprocessor machines. On a singleprocessor machine, the kernel
231 will run faster if you say N here.
233 Note that if you say Y here and choose architecture "586" or
234 "Pentium" under "Processor family", the kernel will not work on 486
235 architectures. Similarly, multiprocessor kernels for the "PPro"
236 architecture may not work on all Pentium based boards.
238 People using multiprocessor machines who say Y here should also say
239 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
240 Management" code will be disabled if you say Y here.
242 See also <file:Documentation/i386/IO-APIC.txt>,
243 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
244 <http://www.tldp.org/docs.html#howto>.
246 If you don't know what to do here, say N.
249 bool "Support x2apic"
250 depends on X86_LOCAL_APIC && X86_64
252 This enables x2apic support on CPUs that have this feature.
254 This allows 32-bit apic IDs (so it can support very large systems),
255 and accesses the local apic via MSRs not via mmio.
257 ( On certain CPU models you may need to enable INTR_REMAP too,
258 to get functional x2apic mode. )
260 If you don't know what to do here, say N.
263 bool "Support sparse irq numbering"
264 depends on PCI_MSI || HT_IRQ
266 This enables support for sparse irqs. This is useful for distro
267 kernels that want to define a high CONFIG_NR_CPUS value but still
268 want to have low kernel memory footprint on smaller machines.
270 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
271 out the irq_desc[] array in a more NUMA-friendly way. )
273 If you don't know what to do here, say N.
275 config NUMA_MIGRATE_IRQ_DESC
276 bool "Move irq desc when changing irq smp_affinity"
277 depends on SPARSE_IRQ && NUMA
280 This enables moving irq_desc to cpu/node that irq will use handled.
282 If you don't know what to do here, say N.
285 bool "Enable MPS table" if ACPI
287 depends on X86_LOCAL_APIC
289 For old smp systems that do not have proper acpi support. Newer systems
290 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
293 bool "Support for big SMP systems with more than 8 CPUs"
294 depends on X86_32 && SMP
296 This option is needed for the systems that have more than 8 CPUs
299 config X86_EXTENDED_PLATFORM
300 bool "Support for extended (non-PC) x86 platforms"
303 If you disable this option then the kernel will only support
304 standard PC platforms. (which covers the vast majority of
307 If you enable this option then you'll be able to select support
308 for the following (non-PC) 32 bit x86 platforms:
312 SGI 320/540 (Visual Workstation)
313 Summit/EXA (IBM x440)
314 Unisys ES7000 IA32 series
316 If you have one of these systems, or if you want to build a
317 generic distribution kernel, say Y here - otherwise say N.
321 config X86_EXTENDED_PLATFORM
322 bool "Support for extended (non-PC) x86 platforms"
325 If you disable this option then the kernel will only support
326 standard PC platforms. (which covers the vast majority of
329 If you enable this option then you'll be able to select support
330 for the following (non-PC) 64 bit x86 platforms:
334 If you have one of these systems, or if you want to build a
335 generic distribution kernel, say Y here - otherwise say N.
337 # This is an alphabetically sorted list of 64 bit extended platforms
338 # Please maintain the alphabetic order if and when there are additions
343 depends on X86_64 && PCI
344 depends on X86_EXTENDED_PLATFORM
346 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
347 supposed to run on these EM64T-based machines. Only choose this option
348 if you have one of these machines.
351 bool "SGI Ultraviolet"
353 depends on X86_EXTENDED_PLATFORM
356 This option is needed in order to support SGI Ultraviolet systems.
357 If you don't have one of these, you should say N here.
359 # Following is an alphabetically sorted list of 32 bit extended platforms
360 # Please maintain the alphabetic order if and when there are additions
365 depends on X86_EXTENDED_PLATFORM
367 Select this for an AMD Elan processor.
369 Do not use this option for K6/Athlon/Opteron processors!
371 If unsure, choose "PC-compatible" instead.
374 bool "RDC R-321x SoC"
376 depends on X86_EXTENDED_PLATFORM
378 select X86_REBOOTFIXUPS
380 This option is needed for RDC R-321x system-on-chip, also known
382 If you don't have one of these chips, you should say N here.
384 config X86_32_NON_STANDARD
385 bool "Support non-standard 32-bit SMP architectures"
386 depends on X86_32 && SMP
387 depends on X86_EXTENDED_PLATFORM
389 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
390 subarchitectures. It is intended for a generic binary kernel.
391 if you select them all, kernel will probe it one by one. and will
394 # Alphabetically sorted list of Non standard 32 bit platforms
397 bool "NUMAQ (IBM/Sequent)"
398 depends on X86_32_NON_STANDARD
402 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
403 NUMA multiquad box. This changes the way that processors are
404 bootstrapped, and uses Clustered Logical APIC addressing mode instead
405 of Flat Logical. You will need a new lynxer.elf file to flash your
406 firmware with - send email to <Martin.Bligh@us.ibm.com>.
409 bool "SGI 320/540 (Visual Workstation)"
410 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
411 depends on X86_32_NON_STANDARD
413 The SGI Visual Workstation series is an IA32-based workstation
414 based on SGI systems chips with some legacy PC hardware attached.
416 Say Y here to create a kernel to run on the SGI 320 or 540.
418 A kernel compiled for the Visual Workstation will run on general
419 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
422 bool "Summit/EXA (IBM x440)"
423 depends on X86_32_NON_STANDARD
425 This option is needed for IBM systems that use the Summit/EXA chipset.
426 In particular, it is needed for the x440.
429 bool "Unisys ES7000 IA32 series"
430 depends on X86_32_NON_STANDARD && X86_BIGSMP
432 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
433 supposed to run on an IA32-based Unisys ES7000 system.
435 config SCHED_OMIT_FRAME_POINTER
437 prompt "Single-depth WCHAN output"
440 Calculate simpler /proc/<PID>/wchan values. If this option
441 is disabled then wchan values will recurse back to the
442 caller function. This provides more accurate wchan values,
443 at the expense of slightly more scheduling overhead.
445 If in doubt, say "Y".
447 menuconfig PARAVIRT_GUEST
448 bool "Paravirtualized guest support"
450 Say Y here to get to see options related to running Linux under
451 various hypervisors. This option alone does not add any kernel code.
453 If you say N, all options in this submenu will be skipped and disabled.
457 source "arch/x86/xen/Kconfig"
460 bool "VMI Guest support"
464 VMI provides a paravirtualized interface to the VMware ESX server
465 (it could be used by other hypervisors in theory too, but is not
466 at the moment), by linking the kernel to a GPL-ed ROM module
467 provided by the hypervisor.
470 bool "KVM paravirtualized clock"
472 select PARAVIRT_CLOCK
474 Turning on this option will allow you to run a paravirtualized clock
475 when running over the KVM hypervisor. Instead of relying on a PIT
476 (or probably other) emulation by the underlying device model, the host
477 provides the guest with timing infrastructure such as time of day, and
481 bool "KVM Guest support"
484 This option enables various optimizations for running under the KVM
487 source "arch/x86/lguest/Kconfig"
490 bool "Enable paravirtualization code"
492 This changes the kernel so it can modify itself when it is run
493 under a hypervisor, potentially improving performance significantly
494 over full virtualization. However, when run without a hypervisor
495 the kernel is theoretically slower and slightly larger.
497 config PARAVIRT_CLOCK
503 config PARAVIRT_DEBUG
504 bool "paravirt-ops debugging"
505 depends on PARAVIRT && DEBUG_KERNEL
507 Enable to debug paravirt_ops internals. Specifically, BUG if
508 a paravirt_op is missing when it is called.
513 This option adds a kernel parameter 'memtest', which allows memtest
515 memtest=0, mean disabled; -- default
516 memtest=1, mean do 1 test pattern;
518 memtest=4, mean do 4 test patterns.
519 If you are unsure how to answer this question, answer N.
521 config X86_SUMMIT_NUMA
523 depends on X86_32 && NUMA && X86_32_NON_STANDARD
525 config X86_CYCLONE_TIMER
527 depends on X86_32_NON_STANDARD
529 source "arch/x86/Kconfig.cpu"
533 prompt "HPET Timer Support" if X86_32
535 Use the IA-PC HPET (High Precision Event Timer) to manage
536 time in preference to the PIT and RTC, if a HPET is
538 HPET is the next generation timer replacing legacy 8254s.
539 The HPET provides a stable time base on SMP
540 systems, unlike the TSC, but it is more expensive to access,
541 as it is off-chip. You can find the HPET spec at
542 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
544 You can safely choose Y here. However, HPET will only be
545 activated if the platform and the BIOS support this feature.
546 Otherwise the 8254 will be used for timing services.
548 Choose N to continue using the legacy 8254 timer.
550 config HPET_EMULATE_RTC
552 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
554 # Mark as embedded because too many people got it wrong.
555 # The code disables itself when not needed.
558 bool "Enable DMI scanning" if EMBEDDED
560 Enabled scanning of DMI to identify machine quirks. Say Y
561 here unless you have verified that your setup is not
562 affected by entries in the DMI blacklist. Required by PNP
566 bool "GART IOMMU support" if EMBEDDED
570 depends on X86_64 && PCI
572 Support for full DMA access of devices with 32bit memory access only
573 on systems with more than 3GB. This is usually needed for USB,
574 sound, many IDE/SATA chipsets and some other devices.
575 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
576 based hardware IOMMU and a software bounce buffer based IOMMU used
577 on Intel systems and as fallback.
578 The code is only active when needed (enough memory and limited
579 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
583 bool "IBM Calgary IOMMU support"
585 depends on X86_64 && PCI && EXPERIMENTAL
587 Support for hardware IOMMUs in IBM's xSeries x366 and x460
588 systems. Needed to run systems with more than 3GB of memory
589 properly with 32-bit PCI devices that do not support DAC
590 (Double Address Cycle). Calgary also supports bus level
591 isolation, where all DMAs pass through the IOMMU. This
592 prevents them from going anywhere except their intended
593 destination. This catches hard-to-find kernel bugs and
594 mis-behaving drivers and devices that do not use the DMA-API
595 properly to set up their DMA buffers. The IOMMU can be
596 turned off at boot time with the iommu=off parameter.
597 Normally the kernel will make the right choice by itself.
600 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
602 prompt "Should Calgary be enabled by default?"
603 depends on CALGARY_IOMMU
605 Should Calgary be enabled by default? if you choose 'y', Calgary
606 will be used (if it exists). If you choose 'n', Calgary will not be
607 used even if it exists. If you choose 'n' and would like to use
608 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
612 bool "AMD IOMMU support"
615 depends on X86_64 && PCI && ACPI
617 With this option you can enable support for AMD IOMMU hardware in
618 your system. An IOMMU is a hardware component which provides
619 remapping of DMA memory accesses from devices. With an AMD IOMMU you
620 can isolate the the DMA memory of different devices and protect the
621 system from misbehaving device drivers or hardware.
623 You can find out if your system has an AMD IOMMU if you look into
624 your BIOS for an option to enable it or if you have an IVRS ACPI
627 config AMD_IOMMU_STATS
628 bool "Export AMD IOMMU statistics to debugfs"
632 This option enables code in the AMD IOMMU driver to collect various
633 statistics about whats happening in the driver and exports that
634 information to userspace via debugfs.
637 # need this always selected by IOMMU for the VIA workaround
641 Support for software bounce buffers used on x86-64 systems
642 which don't have a hardware IOMMU (e.g. the current generation
643 of Intel's x86-64 CPUs). Using this PCI devices which can only
644 access 32-bits of memory can be used on systems with more than
645 3 GB of memory. If unsure, say Y.
648 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
651 def_bool (AMD_IOMMU || DMAR)
654 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
655 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
656 select CPUMASK_OFFSTACK
659 Configure maximum number of CPUS and NUMA Nodes for this architecture.
663 int "Maximum number of CPUs" if SMP && !MAXSMP
664 range 2 512 if SMP && !MAXSMP
666 default "4096" if MAXSMP
667 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
670 This allows you to specify the maximum number of CPUs which this
671 kernel will support. The maximum supported value is 512 and the
672 minimum value which makes sense is 2.
674 This is purely to save memory - each supported CPU adds
675 approximately eight kilobytes to the kernel image.
678 bool "SMT (Hyperthreading) scheduler support"
681 SMT scheduler support improves the CPU scheduler's decision making
682 when dealing with Intel Pentium 4 chips with HyperThreading at a
683 cost of slightly increased overhead in some places. If unsure say
688 prompt "Multi-core scheduler support"
691 Multi-core scheduler support improves the CPU scheduler's decision
692 making when dealing with multi-core CPU chips at a cost of slightly
693 increased overhead in some places. If unsure say N here.
695 source "kernel/Kconfig.preempt"
698 bool "Local APIC support on uniprocessors"
699 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
701 A local APIC (Advanced Programmable Interrupt Controller) is an
702 integrated interrupt controller in the CPU. If you have a single-CPU
703 system which has a processor with a local APIC, you can say Y here to
704 enable and use it. If you say Y here even though your machine doesn't
705 have a local APIC, then the kernel will still run with no slowdown at
706 all. The local APIC supports CPU-generated self-interrupts (timer,
707 performance counters), and the NMI watchdog which detects hard
711 bool "IO-APIC support on uniprocessors"
712 depends on X86_UP_APIC
714 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
715 SMP-capable replacement for PC-style interrupt controllers. Most
716 SMP systems and many recent uniprocessor systems have one.
718 If you have a single-CPU system with an IO-APIC, you can say Y here
719 to use it. If you say Y here even though your machine doesn't have
720 an IO-APIC, then the kernel will still run with no slowdown at all.
722 config X86_LOCAL_APIC
724 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
728 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
730 config X86_VISWS_APIC
732 depends on X86_32 && X86_VISWS
734 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
735 bool "Reroute for broken boot IRQs"
737 depends on X86_IO_APIC
739 This option enables a workaround that fixes a source of
740 spurious interrupts. This is recommended when threaded
741 interrupt handling is used on systems where the generation of
742 superfluous "boot interrupts" cannot be disabled.
744 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
745 entry in the chipset's IO-APIC is masked (as, e.g. the RT
746 kernel does during interrupt handling). On chipsets where this
747 boot IRQ generation cannot be disabled, this workaround keeps
748 the original IRQ line masked so that only the equivalent "boot
749 IRQ" is delivered to the CPUs. The workaround also tells the
750 kernel to set up the IRQ handler on the boot IRQ line. In this
751 way only one interrupt is delivered to the kernel. Otherwise
752 the spurious second interrupt may cause the kernel to bring
753 down (vital) interrupt lines.
755 Only affects "broken" chipsets. Interrupt sharing may be
756 increased on these systems.
759 bool "Machine Check Exception"
761 Machine Check Exception support allows the processor to notify the
762 kernel if it detects a problem (e.g. overheating, component failure).
763 The action the kernel takes depends on the severity of the problem,
764 ranging from a warning message on the console, to halting the machine.
765 Your processor must be a Pentium or newer to support this - check the
766 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
767 have a design flaw which leads to false MCE events - hence MCE is
768 disabled on all P5 processors, unless explicitly enabled with "mce"
769 as a boot argument. Similarly, if MCE is built in and creates a
770 problem on some new non-standard machine, you can boot with "nomce"
771 to disable it. MCE support simply ignores non-MCE processors like
772 the 386 and 486, so nearly everyone can say Y here.
776 prompt "Intel MCE features"
777 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
779 Additional support for intel specific MCE features such as
784 prompt "AMD MCE features"
785 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
787 Additional support for AMD specific MCE features such as
788 the DRAM Error Threshold.
790 config X86_MCE_NONFATAL
791 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
792 depends on X86_32 && X86_MCE
794 Enabling this feature starts a timer that triggers every 5 seconds which
795 will look at the machine check registers to see if anything happened.
796 Non-fatal problems automatically get corrected (but still logged).
797 Disable this if you don't want to see these messages.
798 Seeing the messages this option prints out may be indicative of dying
799 or out-of-spec (ie, overclocked) hardware.
800 This option only does something on certain CPUs.
801 (AMD Athlon/Duron and Intel Pentium 4)
803 config X86_MCE_P4THERMAL
804 bool "check for P4 thermal throttling interrupt."
805 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
807 Enabling this feature will cause a message to be printed when the P4
808 enters thermal throttling.
811 bool "Enable VM86 support" if EMBEDDED
815 This option is required by programs like DOSEMU to run 16-bit legacy
816 code on X86 processors. It also may be needed by software like
817 XFree86 to initialize some video cards via BIOS. Disabling this
818 option saves about 6k.
821 tristate "Toshiba Laptop support"
824 This adds a driver to safely access the System Management Mode of
825 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
826 not work on models with a Phoenix BIOS. The System Management Mode
827 is used to set the BIOS and power saving options on Toshiba portables.
829 For information on utilities to make use of this driver see the
830 Toshiba Linux utilities web site at:
831 <http://www.buzzard.org.uk/toshiba/>.
833 Say Y if you intend to run this kernel on a Toshiba portable.
837 tristate "Dell laptop support"
839 This adds a driver to safely access the System Management Mode
840 of the CPU on the Dell Inspiron 8000. The System Management Mode
841 is used to read cpu temperature and cooling fan status and to
842 control the fans on the I8K portables.
844 This driver has been tested only on the Inspiron 8000 but it may
845 also work with other Dell laptops. You can force loading on other
846 models by passing the parameter `force=1' to the module. Use at
849 For information on utilities to make use of this driver see the
850 I8K Linux utilities web site at:
851 <http://people.debian.org/~dz/i8k/>
853 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
856 config X86_REBOOTFIXUPS
857 bool "Enable X86 board specific fixups for reboot"
860 This enables chipset and/or board specific fixups to be done
861 in order to get reboot to work correctly. This is only needed on
862 some combinations of hardware and BIOS. The symptom, for which
863 this config is intended, is when reboot ends with a stalled/hung
866 Currently, the only fixup is for the Geode machines using
867 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
869 Say Y if you want to enable the fixup. Currently, it's safe to
870 enable this option even if you don't need it.
874 tristate "/dev/cpu/microcode - microcode support"
877 If you say Y here, you will be able to update the microcode on
878 certain Intel and AMD processors. The Intel support is for the
879 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
880 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
881 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
882 You will obviously need the actual microcode binary data itself
883 which is not shipped with the Linux kernel.
885 This option selects the general module only, you need to select
886 at least one vendor specific module as well.
888 To compile this driver as a module, choose M here: the
889 module will be called microcode.
891 config MICROCODE_INTEL
892 bool "Intel microcode patch loading support"
897 This options enables microcode patch loading support for Intel
900 For latest news and information on obtaining all the required
901 Intel ingredients for this driver, check:
902 <http://www.urbanmyth.org/microcode/>.
905 bool "AMD microcode patch loading support"
909 If you select this option, microcode patch loading support for AMD
910 processors will be enabled.
912 config MICROCODE_OLD_INTERFACE
917 tristate "/dev/cpu/*/msr - Model-specific register support"
919 This device gives privileged processes access to the x86
920 Model-Specific Registers (MSRs). It is a character device with
921 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
922 MSR accesses are directed to a specific CPU on multi-processor
926 tristate "/dev/cpu/*/cpuid - CPU information support"
928 This device gives processes access to the x86 CPUID instruction to
929 be executed on a specific processor. It is a character device
930 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
934 prompt "High Memory Support"
935 default HIGHMEM4G if !X86_NUMAQ
936 default HIGHMEM64G if X86_NUMAQ
941 depends on !X86_NUMAQ
943 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
944 However, the address space of 32-bit x86 processors is only 4
945 Gigabytes large. That means that, if you have a large amount of
946 physical memory, not all of it can be "permanently mapped" by the
947 kernel. The physical memory that's not permanently mapped is called
950 If you are compiling a kernel which will never run on a machine with
951 more than 1 Gigabyte total physical RAM, answer "off" here (default
952 choice and suitable for most users). This will result in a "3GB/1GB"
953 split: 3GB are mapped so that each process sees a 3GB virtual memory
954 space and the remaining part of the 4GB virtual memory space is used
955 by the kernel to permanently map as much physical memory as
958 If the machine has between 1 and 4 Gigabytes physical RAM, then
961 If more than 4 Gigabytes is used then answer "64GB" here. This
962 selection turns Intel PAE (Physical Address Extension) mode on.
963 PAE implements 3-level paging on IA32 processors. PAE is fully
964 supported by Linux, PAE mode is implemented on all recent Intel
965 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
966 then the kernel will not boot on CPUs that don't support PAE!
968 The actual amount of total physical memory will either be
969 auto detected or can be forced by using a kernel command line option
970 such as "mem=256M". (Try "man bootparam" or see the documentation of
971 your boot loader (lilo or loadlin) about how to pass options to the
972 kernel at boot time.)
974 If unsure, say "off".
978 depends on !X86_NUMAQ
980 Select this if you have a 32-bit processor and between 1 and 4
981 gigabytes of physical RAM.
985 depends on !M386 && !M486
988 Select this if you have a 32-bit processor and more than 4
989 gigabytes of physical RAM.
994 depends on EXPERIMENTAL
995 prompt "Memory split" if EMBEDDED
999 Select the desired split between kernel and user memory.
1001 If the address range available to the kernel is less than the
1002 physical memory installed, the remaining memory will be available
1003 as "high memory". Accessing high memory is a little more costly
1004 than low memory, as it needs to be mapped into the kernel first.
1005 Note that increasing the kernel address space limits the range
1006 available to user programs, making the address space there
1007 tighter. Selecting anything other than the default 3G/1G split
1008 will also likely make your kernel incompatible with binary-only
1011 If you are not absolutely sure what you are doing, leave this
1015 bool "3G/1G user/kernel split"
1016 config VMSPLIT_3G_OPT
1018 bool "3G/1G user/kernel split (for full 1G low memory)"
1020 bool "2G/2G user/kernel split"
1021 config VMSPLIT_2G_OPT
1023 bool "2G/2G user/kernel split (for full 2G low memory)"
1025 bool "1G/3G user/kernel split"
1030 default 0xB0000000 if VMSPLIT_3G_OPT
1031 default 0x80000000 if VMSPLIT_2G
1032 default 0x78000000 if VMSPLIT_2G_OPT
1033 default 0x40000000 if VMSPLIT_1G
1039 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1042 bool "PAE (Physical Address Extension) Support"
1043 depends on X86_32 && !HIGHMEM4G
1045 PAE is required for NX support, and furthermore enables
1046 larger swapspace support for non-overcommit purposes. It
1047 has the cost of more pagetable lookup overhead, and also
1048 consumes more pagetable space per process.
1050 config ARCH_PHYS_ADDR_T_64BIT
1051 def_bool X86_64 || X86_PAE
1053 config DIRECT_GBPAGES
1054 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1058 Allow the kernel linear mapping to use 1GB pages on CPUs that
1059 support it. This can improve the kernel's performance a tiny bit by
1060 reducing TLB pressure. If in doubt, say "Y".
1062 # Common NUMA Features
1064 bool "Numa Memory Allocation and Scheduler Support"
1066 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1067 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1069 Enable NUMA (Non Uniform Memory Access) support.
1071 The kernel will try to allocate memory used by a CPU on the
1072 local memory controller of the CPU and add some more
1073 NUMA awareness to the kernel.
1075 For 64-bit this is recommended if the system is Intel Core i7
1076 (or later), AMD Opteron, or EM64T NUMA.
1078 For 32-bit this is only needed on (rare) 32-bit-only platforms
1079 that support NUMA topologies, such as NUMAQ / Summit, or if you
1080 boot a 32-bit kernel on a 64-bit NUMA platform.
1082 Otherwise, you should say N.
1084 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1085 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1089 prompt "Old style AMD Opteron NUMA detection"
1090 depends on X86_64 && NUMA && PCI
1092 Enable K8 NUMA node topology detection. You should say Y here if
1093 you have a multi processor AMD K8 system. This uses an old
1094 method to read the NUMA configuration directly from the builtin
1095 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1096 instead, which also takes priority if both are compiled in.
1098 config X86_64_ACPI_NUMA
1100 prompt "ACPI NUMA detection"
1101 depends on X86_64 && NUMA && ACPI && PCI
1104 Enable ACPI SRAT based node topology detection.
1106 # Some NUMA nodes have memory ranges that span
1107 # other nodes. Even though a pfn is valid and
1108 # between a node's start and end pfns, it may not
1109 # reside on that node. See memmap_init_zone()
1111 config NODES_SPAN_OTHER_NODES
1113 depends on X86_64_ACPI_NUMA
1116 bool "NUMA emulation"
1117 depends on X86_64 && NUMA
1119 Enable NUMA emulation. A flat machine will be split
1120 into virtual nodes when booted with "numa=fake=N", where N is the
1121 number of nodes. This is only useful for debugging.
1124 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1126 default "9" if MAXSMP
1127 default "6" if X86_64
1128 default "4" if X86_NUMAQ
1130 depends on NEED_MULTIPLE_NODES
1132 Specify the maximum number of NUMA Nodes available on the target
1133 system. Increases memory reserved to accomodate various tables.
1135 config HAVE_ARCH_BOOTMEM
1137 depends on X86_32 && NUMA
1139 config ARCH_HAVE_MEMORY_PRESENT
1141 depends on X86_32 && DISCONTIGMEM
1143 config NEED_NODE_MEMMAP_SIZE
1145 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1147 config HAVE_ARCH_ALLOC_REMAP
1149 depends on X86_32 && NUMA
1151 config ARCH_FLATMEM_ENABLE
1153 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1155 config ARCH_DISCONTIGMEM_ENABLE
1157 depends on NUMA && X86_32
1159 config ARCH_DISCONTIGMEM_DEFAULT
1161 depends on NUMA && X86_32
1163 config ARCH_SPARSEMEM_DEFAULT
1167 config ARCH_SPARSEMEM_ENABLE
1169 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1170 select SPARSEMEM_STATIC if X86_32
1171 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1173 config ARCH_SELECT_MEMORY_MODEL
1175 depends on ARCH_SPARSEMEM_ENABLE
1177 config ARCH_MEMORY_PROBE
1179 depends on MEMORY_HOTPLUG
1184 bool "Allocate 3rd-level pagetables from highmem"
1185 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1187 The VM uses one page table entry for each page of physical memory.
1188 For systems with a lot of RAM, this can be wasteful of precious
1189 low memory. Setting this option will put user-space page table
1190 entries in high memory.
1192 config X86_CHECK_BIOS_CORRUPTION
1193 bool "Check for low memory corruption"
1195 Periodically check for memory corruption in low memory, which
1196 is suspected to be caused by BIOS. Even when enabled in the
1197 configuration, it is disabled at runtime. Enable it by
1198 setting "memory_corruption_check=1" on the kernel command
1199 line. By default it scans the low 64k of memory every 60
1200 seconds; see the memory_corruption_check_size and
1201 memory_corruption_check_period parameters in
1202 Documentation/kernel-parameters.txt to adjust this.
1204 When enabled with the default parameters, this option has
1205 almost no overhead, as it reserves a relatively small amount
1206 of memory and scans it infrequently. It both detects corruption
1207 and prevents it from affecting the running system.
1209 It is, however, intended as a diagnostic tool; if repeatable
1210 BIOS-originated corruption always affects the same memory,
1211 you can use memmap= to prevent the kernel from using that
1214 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1215 bool "Set the default setting of memory_corruption_check"
1216 depends on X86_CHECK_BIOS_CORRUPTION
1219 Set whether the default state of memory_corruption_check is
1222 config X86_RESERVE_LOW_64K
1223 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1226 Reserve the first 64K of physical RAM on BIOSes that are known
1227 to potentially corrupt that memory range. A numbers of BIOSes are
1228 known to utilize this area during suspend/resume, so it must not
1229 be used by the kernel.
1231 Set this to N if you are absolutely sure that you trust the BIOS
1232 to get all its memory reservations and usages right.
1234 If you have doubts about the BIOS (e.g. suspend/resume does not
1235 work or there's kernel crashes after certain hardware hotplug
1236 events) and it's not AMI or Phoenix, then you might want to enable
1237 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1238 corruption patterns.
1242 config MATH_EMULATION
1244 prompt "Math emulation" if X86_32
1246 Linux can emulate a math coprocessor (used for floating point
1247 operations) if you don't have one. 486DX and Pentium processors have
1248 a math coprocessor built in, 486SX and 386 do not, unless you added
1249 a 487DX or 387, respectively. (The messages during boot time can
1250 give you some hints here ["man dmesg"].) Everyone needs either a
1251 coprocessor or this emulation.
1253 If you don't have a math coprocessor, you need to say Y here; if you
1254 say Y here even though you have a coprocessor, the coprocessor will
1255 be used nevertheless. (This behavior can be changed with the kernel
1256 command line option "no387", which comes handy if your coprocessor
1257 is broken. Try "man bootparam" or see the documentation of your boot
1258 loader (lilo or loadlin) about how to pass options to the kernel at
1259 boot time.) This means that it is a good idea to say Y here if you
1260 intend to use this kernel on different machines.
1262 More information about the internals of the Linux math coprocessor
1263 emulation can be found in <file:arch/x86/math-emu/README>.
1265 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1266 kernel, it won't hurt.
1269 bool "MTRR (Memory Type Range Register) support"
1271 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1272 the Memory Type Range Registers (MTRRs) may be used to control
1273 processor access to memory ranges. This is most useful if you have
1274 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1275 allows bus write transfers to be combined into a larger transfer
1276 before bursting over the PCI/AGP bus. This can increase performance
1277 of image write operations 2.5 times or more. Saying Y here creates a
1278 /proc/mtrr file which may be used to manipulate your processor's
1279 MTRRs. Typically the X server should use this.
1281 This code has a reasonably generic interface so that similar
1282 control registers on other processors can be easily supported
1285 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1286 Registers (ARRs) which provide a similar functionality to MTRRs. For
1287 these, the ARRs are used to emulate the MTRRs.
1288 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1289 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1290 write-combining. All of these processors are supported by this code
1291 and it makes sense to say Y here if you have one of them.
1293 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1294 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1295 can lead to all sorts of problems, so it's good to say Y here.
1297 You can safely say Y even if your machine doesn't have MTRRs, you'll
1298 just add about 9 KB to your kernel.
1300 See <file:Documentation/x86/mtrr.txt> for more information.
1302 config MTRR_SANITIZER
1304 prompt "MTRR cleanup support"
1307 Convert MTRR layout from continuous to discrete, so X drivers can
1308 add writeback entries.
1310 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1311 The largest mtrr entry size for a continous block can be set with
1316 config MTRR_SANITIZER_ENABLE_DEFAULT
1317 int "MTRR cleanup enable value (0-1)"
1320 depends on MTRR_SANITIZER
1322 Enable mtrr cleanup default value
1324 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1325 int "MTRR cleanup spare reg num (0-7)"
1328 depends on MTRR_SANITIZER
1330 mtrr cleanup spare entries default, it can be changed via
1331 mtrr_spare_reg_nr=N on the kernel command line.
1335 prompt "x86 PAT support"
1338 Use PAT attributes to setup page level cache control.
1340 PATs are the modern equivalents of MTRRs and are much more
1341 flexible than MTRRs.
1343 Say N here if you see bootup problems (boot crash, boot hang,
1344 spontaneous reboots) or a non-working video driver.
1349 bool "EFI runtime service support"
1352 This enables the kernel to use EFI runtime services that are
1353 available (such as the EFI variable services).
1355 This option is only useful on systems that have EFI firmware.
1356 In addition, you should use the latest ELILO loader available
1357 at <http://elilo.sourceforge.net> in order to take advantage
1358 of EFI runtime services. However, even with this option, the
1359 resultant kernel should continue to boot on existing non-EFI
1364 prompt "Enable seccomp to safely compute untrusted bytecode"
1366 This kernel feature is useful for number crunching applications
1367 that may need to compute untrusted bytecode during their
1368 execution. By using pipes or other transports made available to
1369 the process as file descriptors supporting the read/write
1370 syscalls, it's possible to isolate those applications in
1371 their own address space using seccomp. Once seccomp is
1372 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1373 and the task is only allowed to execute a few safe syscalls
1374 defined by each seccomp mode.
1376 If unsure, say Y. Only embedded should say N here.
1378 config CC_STACKPROTECTOR_ALL
1381 config CC_STACKPROTECTOR
1382 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1383 select CC_STACKPROTECTOR_ALL
1385 This option turns on the -fstack-protector GCC feature. This
1386 feature puts, at the beginning of functions, a canary value on
1387 the stack just before the return address, and validates
1388 the value just before actually returning. Stack based buffer
1389 overflows (that need to overwrite this return address) now also
1390 overwrite the canary, which gets detected and the attack is then
1391 neutralized via a kernel panic.
1393 This feature requires gcc version 4.2 or above, or a distribution
1394 gcc with the feature backported. Older versions are automatically
1395 detected and for those versions, this configuration option is
1396 ignored. (and a warning is printed during bootup)
1398 source kernel/Kconfig.hz
1401 bool "kexec system call"
1403 kexec is a system call that implements the ability to shutdown your
1404 current kernel, and to start another kernel. It is like a reboot
1405 but it is independent of the system firmware. And like a reboot
1406 you can start any kernel with it, not just Linux.
1408 The name comes from the similarity to the exec system call.
1410 It is an ongoing process to be certain the hardware in a machine
1411 is properly shutdown, so do not be surprised if this code does not
1412 initially work for you. It may help to enable device hotplugging
1413 support. As of this writing the exact hardware interface is
1414 strongly in flux, so no good recommendation can be made.
1417 bool "kernel crash dumps"
1418 depends on X86_64 || (X86_32 && HIGHMEM)
1420 Generate crash dump after being started by kexec.
1421 This should be normally only set in special crash dump kernels
1422 which are loaded in the main kernel with kexec-tools into
1423 a specially reserved region and then later executed after
1424 a crash by kdump/kexec. The crash dump kernel must be compiled
1425 to a memory address not used by the main kernel or BIOS using
1426 PHYSICAL_START, or it must be built as a relocatable image
1427 (CONFIG_RELOCATABLE=y).
1428 For more details see Documentation/kdump/kdump.txt
1431 bool "kexec jump (EXPERIMENTAL)"
1432 depends on EXPERIMENTAL
1433 depends on KEXEC && HIBERNATION && X86_32
1435 Jump between original kernel and kexeced kernel and invoke
1436 code in physical address mode via KEXEC
1438 config PHYSICAL_START
1439 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1440 default "0x1000000" if X86_NUMAQ
1441 default "0x200000" if X86_64
1444 This gives the physical address where the kernel is loaded.
1446 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1447 bzImage will decompress itself to above physical address and
1448 run from there. Otherwise, bzImage will run from the address where
1449 it has been loaded by the boot loader and will ignore above physical
1452 In normal kdump cases one does not have to set/change this option
1453 as now bzImage can be compiled as a completely relocatable image
1454 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1455 address. This option is mainly useful for the folks who don't want
1456 to use a bzImage for capturing the crash dump and want to use a
1457 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1458 to be specifically compiled to run from a specific memory area
1459 (normally a reserved region) and this option comes handy.
1461 So if you are using bzImage for capturing the crash dump, leave
1462 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1463 Otherwise if you plan to use vmlinux for capturing the crash dump
1464 change this value to start of the reserved region (Typically 16MB
1465 0x1000000). In other words, it can be set based on the "X" value as
1466 specified in the "crashkernel=YM@XM" command line boot parameter
1467 passed to the panic-ed kernel. Typically this parameter is set as
1468 crashkernel=64M@16M. Please take a look at
1469 Documentation/kdump/kdump.txt for more details about crash dumps.
1471 Usage of bzImage for capturing the crash dump is recommended as
1472 one does not have to build two kernels. Same kernel can be used
1473 as production kernel and capture kernel. Above option should have
1474 gone away after relocatable bzImage support is introduced. But it
1475 is present because there are users out there who continue to use
1476 vmlinux for dump capture. This option should go away down the
1479 Don't change this unless you know what you are doing.
1482 bool "Build a relocatable kernel (EXPERIMENTAL)"
1483 depends on EXPERIMENTAL
1485 This builds a kernel image that retains relocation information
1486 so it can be loaded someplace besides the default 1MB.
1487 The relocations tend to make the kernel binary about 10% larger,
1488 but are discarded at runtime.
1490 One use is for the kexec on panic case where the recovery kernel
1491 must live at a different physical address than the primary
1494 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1495 it has been loaded at and the compile time physical address
1496 (CONFIG_PHYSICAL_START) is ignored.
1498 config PHYSICAL_ALIGN
1500 prompt "Alignment value to which kernel should be aligned" if X86_32
1501 default "0x100000" if X86_32
1502 default "0x200000" if X86_64
1503 range 0x2000 0x400000
1505 This value puts the alignment restrictions on physical address
1506 where kernel is loaded and run from. Kernel is compiled for an
1507 address which meets above alignment restriction.
1509 If bootloader loads the kernel at a non-aligned address and
1510 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1511 address aligned to above value and run from there.
1513 If bootloader loads the kernel at a non-aligned address and
1514 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1515 load address and decompress itself to the address it has been
1516 compiled for and run from there. The address for which kernel is
1517 compiled already meets above alignment restrictions. Hence the
1518 end result is that kernel runs from a physical address meeting
1519 above alignment restrictions.
1521 Don't change this unless you know what you are doing.
1524 bool "Support for hot-pluggable CPUs"
1525 depends on SMP && HOTPLUG
1527 Say Y here to allow turning CPUs off and on. CPUs can be
1528 controlled through /sys/devices/system/cpu.
1529 ( Note: power management support will enable this option
1530 automatically on SMP systems. )
1531 Say N if you want to disable CPU hotplug.
1535 prompt "Compat VDSO support"
1536 depends on X86_32 || IA32_EMULATION
1538 Map the 32-bit VDSO to the predictable old-style address too.
1540 Say N here if you are running a sufficiently recent glibc
1541 version (2.3.3 or later), to remove the high-mapped
1542 VDSO mapping and to exclusively use the randomized VDSO.
1547 bool "Built-in kernel command line"
1550 Allow for specifying boot arguments to the kernel at
1551 build time. On some systems (e.g. embedded ones), it is
1552 necessary or convenient to provide some or all of the
1553 kernel boot arguments with the kernel itself (that is,
1554 to not rely on the boot loader to provide them.)
1556 To compile command line arguments into the kernel,
1557 set this option to 'Y', then fill in the
1558 the boot arguments in CONFIG_CMDLINE.
1560 Systems with fully functional boot loaders (i.e. non-embedded)
1561 should leave this option set to 'N'.
1564 string "Built-in kernel command string"
1565 depends on CMDLINE_BOOL
1568 Enter arguments here that should be compiled into the kernel
1569 image and used at boot time. If the boot loader provides a
1570 command line at boot time, it is appended to this string to
1571 form the full kernel command line, when the system boots.
1573 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1574 change this behavior.
1576 In most cases, the command line (whether built-in or provided
1577 by the boot loader) should specify the device for the root
1580 config CMDLINE_OVERRIDE
1581 bool "Built-in command line overrides boot loader arguments"
1583 depends on CMDLINE_BOOL
1585 Set this option to 'Y' to have the kernel ignore the boot loader
1586 command line, and use ONLY the built-in command line.
1588 This is used to work around broken boot loaders. This should
1589 be set to 'N' under normal conditions.
1593 config ARCH_ENABLE_MEMORY_HOTPLUG
1595 depends on X86_64 || (X86_32 && HIGHMEM)
1597 config ARCH_ENABLE_MEMORY_HOTREMOVE
1599 depends on MEMORY_HOTPLUG
1601 config HAVE_ARCH_EARLY_PFN_TO_NID
1605 menu "Power management and ACPI options"
1607 config ARCH_HIBERNATION_HEADER
1609 depends on X86_64 && HIBERNATION
1611 source "kernel/power/Kconfig"
1613 source "drivers/acpi/Kconfig"
1618 depends on APM || APM_MODULE
1621 tristate "APM (Advanced Power Management) BIOS support"
1622 depends on X86_32 && PM_SLEEP
1624 APM is a BIOS specification for saving power using several different
1625 techniques. This is mostly useful for battery powered laptops with
1626 APM compliant BIOSes. If you say Y here, the system time will be
1627 reset after a RESUME operation, the /proc/apm device will provide
1628 battery status information, and user-space programs will receive
1629 notification of APM "events" (e.g. battery status change).
1631 If you select "Y" here, you can disable actual use of the APM
1632 BIOS by passing the "apm=off" option to the kernel at boot time.
1634 Note that the APM support is almost completely disabled for
1635 machines with more than one CPU.
1637 In order to use APM, you will need supporting software. For location
1638 and more information, read <file:Documentation/power/pm.txt> and the
1639 Battery Powered Linux mini-HOWTO, available from
1640 <http://www.tldp.org/docs.html#howto>.
1642 This driver does not spin down disk drives (see the hdparm(8)
1643 manpage ("man 8 hdparm") for that), and it doesn't turn off
1644 VESA-compliant "green" monitors.
1646 This driver does not support the TI 4000M TravelMate and the ACER
1647 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1648 desktop machines also don't have compliant BIOSes, and this driver
1649 may cause those machines to panic during the boot phase.
1651 Generally, if you don't have a battery in your machine, there isn't
1652 much point in using this driver and you should say N. If you get
1653 random kernel OOPSes or reboots that don't seem to be related to
1654 anything, try disabling/enabling this option (or disabling/enabling
1657 Some other things you should try when experiencing seemingly random,
1660 1) make sure that you have enough swap space and that it is
1662 2) pass the "no-hlt" option to the kernel
1663 3) switch on floating point emulation in the kernel and pass
1664 the "no387" option to the kernel
1665 4) pass the "floppy=nodma" option to the kernel
1666 5) pass the "mem=4M" option to the kernel (thereby disabling
1667 all but the first 4 MB of RAM)
1668 6) make sure that the CPU is not over clocked.
1669 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1670 8) disable the cache from your BIOS settings
1671 9) install a fan for the video card or exchange video RAM
1672 10) install a better fan for the CPU
1673 11) exchange RAM chips
1674 12) exchange the motherboard.
1676 To compile this driver as a module, choose M here: the
1677 module will be called apm.
1681 config APM_IGNORE_USER_SUSPEND
1682 bool "Ignore USER SUSPEND"
1684 This option will ignore USER SUSPEND requests. On machines with a
1685 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1686 series notebooks, it is necessary to say Y because of a BIOS bug.
1688 config APM_DO_ENABLE
1689 bool "Enable PM at boot time"
1691 Enable APM features at boot time. From page 36 of the APM BIOS
1692 specification: "When disabled, the APM BIOS does not automatically
1693 power manage devices, enter the Standby State, enter the Suspend
1694 State, or take power saving steps in response to CPU Idle calls."
1695 This driver will make CPU Idle calls when Linux is idle (unless this
1696 feature is turned off -- see "Do CPU IDLE calls", below). This
1697 should always save battery power, but more complicated APM features
1698 will be dependent on your BIOS implementation. You may need to turn
1699 this option off if your computer hangs at boot time when using APM
1700 support, or if it beeps continuously instead of suspending. Turn
1701 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1702 T400CDT. This is off by default since most machines do fine without
1706 bool "Make CPU Idle calls when idle"
1708 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1709 On some machines, this can activate improved power savings, such as
1710 a slowed CPU clock rate, when the machine is idle. These idle calls
1711 are made after the idle loop has run for some length of time (e.g.,
1712 333 mS). On some machines, this will cause a hang at boot time or
1713 whenever the CPU becomes idle. (On machines with more than one CPU,
1714 this option does nothing.)
1716 config APM_DISPLAY_BLANK
1717 bool "Enable console blanking using APM"
1719 Enable console blanking using the APM. Some laptops can use this to
1720 turn off the LCD backlight when the screen blanker of the Linux
1721 virtual console blanks the screen. Note that this is only used by
1722 the virtual console screen blanker, and won't turn off the backlight
1723 when using the X Window system. This also doesn't have anything to
1724 do with your VESA-compliant power-saving monitor. Further, this
1725 option doesn't work for all laptops -- it might not turn off your
1726 backlight at all, or it might print a lot of errors to the console,
1727 especially if you are using gpm.
1729 config APM_ALLOW_INTS
1730 bool "Allow interrupts during APM BIOS calls"
1732 Normally we disable external interrupts while we are making calls to
1733 the APM BIOS as a measure to lessen the effects of a badly behaving
1734 BIOS implementation. The BIOS should reenable interrupts if it
1735 needs to. Unfortunately, some BIOSes do not -- especially those in
1736 many of the newer IBM Thinkpads. If you experience hangs when you
1737 suspend, try setting this to Y. Otherwise, say N.
1741 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1743 source "drivers/cpuidle/Kconfig"
1745 source "drivers/idle/Kconfig"
1750 menu "Bus options (PCI etc.)"
1755 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1757 Find out whether you have a PCI motherboard. PCI is the name of a
1758 bus system, i.e. the way the CPU talks to the other stuff inside
1759 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1760 VESA. If you have PCI, say Y, otherwise N.
1763 prompt "PCI access mode"
1764 depends on X86_32 && PCI
1767 On PCI systems, the BIOS can be used to detect the PCI devices and
1768 determine their configuration. However, some old PCI motherboards
1769 have BIOS bugs and may crash if this is done. Also, some embedded
1770 PCI-based systems don't have any BIOS at all. Linux can also try to
1771 detect the PCI hardware directly without using the BIOS.
1773 With this option, you can specify how Linux should detect the
1774 PCI devices. If you choose "BIOS", the BIOS will be used,
1775 if you choose "Direct", the BIOS won't be used, and if you
1776 choose "MMConfig", then PCI Express MMCONFIG will be used.
1777 If you choose "Any", the kernel will try MMCONFIG, then the
1778 direct access method and falls back to the BIOS if that doesn't
1779 work. If unsure, go with the default, which is "Any".
1784 config PCI_GOMMCONFIG
1801 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1803 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1806 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1810 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1814 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1821 bool "Support mmconfig PCI config space access"
1822 depends on X86_64 && PCI && ACPI
1825 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1826 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1828 DMA remapping (DMAR) devices support enables independent address
1829 translations for Direct Memory Access (DMA) from devices.
1830 These DMA remapping devices are reported via ACPI tables
1831 and include PCI device scope covered by these DMA
1834 config DMAR_DEFAULT_ON
1836 prompt "Enable DMA Remapping Devices by default"
1839 Selecting this option will enable a DMAR device at boot time if
1840 one is found. If this option is not selected, DMAR support can
1841 be enabled by passing intel_iommu=on to the kernel. It is
1842 recommended you say N here while the DMAR code remains
1847 prompt "Support for Graphics workaround"
1850 Current Graphics drivers tend to use physical address
1851 for DMA and avoid using DMA APIs. Setting this config
1852 option permits the IOMMU driver to set a unity map for
1853 all the OS-visible memory. Hence the driver can continue
1854 to use physical addresses for DMA.
1856 config DMAR_FLOPPY_WA
1860 Floppy disk drivers are know to bypass DMA API calls
1861 thereby failing to work when IOMMU is enabled. This
1862 workaround will setup a 1:1 mapping for the first
1863 16M to make floppy (an ISA device) work.
1866 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1867 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1870 Supports Interrupt remapping for IO-APIC and MSI devices.
1871 To use x2apic mode in the CPU's which support x2APIC enhancements or
1872 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1874 source "drivers/pci/pcie/Kconfig"
1876 source "drivers/pci/Kconfig"
1878 # x86_64 have no ISA slots, but do have ISA-style DMA.
1887 Find out whether you have ISA slots on your motherboard. ISA is the
1888 name of a bus system, i.e. the way the CPU talks to the other stuff
1889 inside your box. Other bus systems are PCI, EISA, MicroChannel
1890 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1891 newer boards don't support it. If you have ISA, say Y, otherwise N.
1897 The Extended Industry Standard Architecture (EISA) bus was
1898 developed as an open alternative to the IBM MicroChannel bus.
1900 The EISA bus provided some of the features of the IBM MicroChannel
1901 bus while maintaining backward compatibility with cards made for
1902 the older ISA bus. The EISA bus saw limited use between 1988 and
1903 1995 when it was made obsolete by the PCI bus.
1905 Say Y here if you are building a kernel for an EISA-based machine.
1909 source "drivers/eisa/Kconfig"
1914 MicroChannel Architecture is found in some IBM PS/2 machines and
1915 laptops. It is a bus system similar to PCI or ISA. See
1916 <file:Documentation/mca.txt> (and especially the web page given
1917 there) before attempting to build an MCA bus kernel.
1919 source "drivers/mca/Kconfig"
1922 tristate "NatSemi SCx200 support"
1924 This provides basic support for National Semiconductor's
1925 (now AMD's) Geode processors. The driver probes for the
1926 PCI-IDs of several on-chip devices, so its a good dependency
1927 for other scx200_* drivers.
1929 If compiled as a module, the driver is named scx200.
1931 config SCx200HR_TIMER
1932 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1933 depends on SCx200 && GENERIC_TIME
1936 This driver provides a clocksource built upon the on-chip
1937 27MHz high-resolution timer. Its also a workaround for
1938 NSC Geode SC-1100's buggy TSC, which loses time when the
1939 processor goes idle (as is done by the scheduler). The
1940 other workaround is idle=poll boot option.
1942 config GEODE_MFGPT_TIMER
1944 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1945 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1947 This driver provides a clock event source based on the MFGPT
1948 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1949 MFGPTs have a better resolution and max interval than the
1950 generic PIT, and are suitable for use as high-res timers.
1953 bool "One Laptop Per Child support"
1956 Add support for detecting the unique features of the OLPC
1963 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1965 source "drivers/pcmcia/Kconfig"
1967 source "drivers/pci/hotplug/Kconfig"
1972 menu "Executable file formats / Emulations"
1974 source "fs/Kconfig.binfmt"
1976 config IA32_EMULATION
1977 bool "IA32 Emulation"
1979 select COMPAT_BINFMT_ELF
1981 Include code to run 32-bit programs under a 64-bit kernel. You should
1982 likely turn this on, unless you're 100% sure that you don't have any
1983 32-bit programs left.
1986 tristate "IA32 a.out support"
1987 depends on IA32_EMULATION
1989 Support old a.out binaries in the 32bit emulation.
1993 depends on IA32_EMULATION
1995 config COMPAT_FOR_U64_ALIGNMENT
1999 config SYSVIPC_COMPAT
2001 depends on COMPAT && SYSVIPC
2006 config HAVE_ATOMIC_IOMAP
2010 source "net/Kconfig"
2012 source "drivers/Kconfig"
2014 source "drivers/firmware/Kconfig"
2018 source "arch/x86/Kconfig.debug"
2020 source "security/Kconfig"
2022 source "crypto/Kconfig"
2024 source "arch/x86/kvm/Kconfig"
2026 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob