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
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
145 config ARCH_SUSPEND_POSSIBLE
152 config ARCH_POPULATES_NODE_MAP
159 config ARCH_SUPPORTS_OPTIMIZED_INLINING
162 # Use the generic interrupt handling code in kernel/irq/:
163 config GENERIC_HARDIRQS
167 config GENERIC_IRQ_PROBE
171 config GENERIC_PENDING_IRQ
173 depends on GENERIC_HARDIRQS && SMP
176 config USE_GENERIC_SMP_HELPERS
182 depends on X86_32 && SMP
186 depends on X86_64 && SMP
193 config X86_TRAMPOLINE
195 depends on SMP || (64BIT && ACPI_SLEEP)
200 source "init/Kconfig"
201 source "kernel/Kconfig.freezer"
203 menu "Processor type and features"
205 source "kernel/time/Kconfig"
208 bool "Symmetric multi-processing support"
210 This enables support for systems with more than one CPU. If you have
211 a system with only one CPU, like most personal computers, say N. If
212 you have a system with more than one CPU, say Y.
214 If you say N here, the kernel will run on single and multiprocessor
215 machines, but will use only one CPU of a multiprocessor machine. If
216 you say Y here, the kernel will run on many, but not all,
217 singleprocessor machines. On a singleprocessor machine, the kernel
218 will run faster if you say N here.
220 Note that if you say Y here and choose architecture "586" or
221 "Pentium" under "Processor family", the kernel will not work on 486
222 architectures. Similarly, multiprocessor kernels for the "PPro"
223 architecture may not work on all Pentium based boards.
225 People using multiprocessor machines who say Y here should also say
226 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
227 Management" code will be disabled if you say Y here.
229 See also <file:Documentation/i386/IO-APIC.txt>,
230 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
231 <http://www.tldp.org/docs.html#howto>.
233 If you don't know what to do here, say N.
236 bool "Support sparse irq numbering"
237 depends on PCI_MSI || HT_IRQ
239 This enables support for sparse irqs. This is useful for distro
240 kernels that want to define a high CONFIG_NR_CPUS value but still
241 want to have low kernel memory footprint on smaller machines.
243 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
244 out the irq_desc[] array in a more NUMA-friendly way. )
246 If you don't know what to do here, say N.
248 config NUMA_MIGRATE_IRQ_DESC
249 bool "Move irq desc when changing irq smp_affinity"
250 depends on SPARSE_IRQ && NUMA
253 This enables moving irq_desc to cpu/node that irq will use handled.
255 If you don't know what to do here, say N.
258 bool "Enable MPS table" if ACPI
260 depends on X86_LOCAL_APIC
262 For old smp systems that do not have proper acpi support. Newer systems
263 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
268 config X86_NON_STANDARD
269 bool "Support for non-standard x86 platforms"
271 If you disable this option then the kernel will only support
272 standard PC platforms. (which covers the vast majority of
275 If you enable this option then you'll be able to select a number
276 of less common non-PC x86 platforms: VisWS, RDC321, SGI/UV.
278 If you have one of these systems, or if you want to build a
279 generic distribution kernel, say Y here - otherwise say N.
282 bool "SGI 320/540 (Visual Workstation)"
283 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
284 depends on X86_NON_STANDARD
286 The SGI Visual Workstation series is an IA32-based workstation
287 based on SGI systems chips with some legacy PC hardware attached.
289 Say Y here to create a kernel to run on the SGI 320 or 540.
291 A kernel compiled for the Visual Workstation will run on general
292 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
295 bool "RDC R-321x SoC"
297 depends on X86_NON_STANDARD
299 select X86_REBOOTFIXUPS
301 This option is needed for RDC R-321x system-on-chip, also known
303 If you don't have one of these chips, you should say N here.
306 bool "SGI Ultraviolet"
308 depends on X86_NON_STANDARD
310 This option is needed in order to support SGI Ultraviolet systems.
311 If you don't have one of these, you should say N here.
314 bool "Support for ScaleMP vSMP"
316 depends on X86_64 && PCI
317 depends on X86_NON_STANDARD
319 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
320 supposed to run on these EM64T-based machines. Only choose this option
321 if you have one of these machines.
326 depends on X86_NON_STANDARD
328 Select this for an AMD Elan processor.
330 Do not use this option for K6/Athlon/Opteron processors!
332 If unsure, choose "PC-compatible" instead.
334 config X86_32_NON_STANDARD
335 bool "Support non-standard 32-bit SMP architectures"
336 depends on X86_32 && SMP
337 depends on X86_NON_STANDARD
339 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
340 subarchitectures. It is intended for a generic binary kernel.
341 if you select them all, kernel will probe it one by one. and will
345 bool "Support for big SMP systems with more than 8 CPUs"
346 depends on X86_32_NON_STANDARD
348 This option is needed for the systems that have more than 8 CPUs
349 and if the system is not of any sub-arch type above.
352 bool "NUMAQ (IBM/Sequent)"
353 depends on X86_32_NON_STANDARD
357 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
358 NUMA multiquad box. This changes the way that processors are
359 bootstrapped, and uses Clustered Logical APIC addressing mode instead
360 of Flat Logical. You will need a new lynxer.elf file to flash your
361 firmware with - send email to <Martin.Bligh@us.ibm.com>.
364 bool "Summit/EXA (IBM x440)"
365 depends on X86_32_NON_STANDARD
367 This option is needed for IBM systems that use the Summit/EXA chipset.
368 In particular, it is needed for the x440.
371 bool "Support for Unisys ES7000 IA32 series"
372 depends on X86_32_NON_STANDARD
374 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
375 supposed to run on an IA32-based Unisys ES7000 system.
379 depends on SMP && !PCI && BROKEN
380 depends on X86_32_NON_STANDARD
382 Voyager is an MCA-based 32-way capable SMP architecture proprietary
383 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
387 If you do not specifically know you have a Voyager based machine,
388 say N here, otherwise the kernel you build will not be bootable.
390 config SCHED_OMIT_FRAME_POINTER
392 prompt "Single-depth WCHAN output"
395 Calculate simpler /proc/<PID>/wchan values. If this option
396 is disabled then wchan values will recurse back to the
397 caller function. This provides more accurate wchan values,
398 at the expense of slightly more scheduling overhead.
400 If in doubt, say "Y".
402 menuconfig PARAVIRT_GUEST
403 bool "Paravirtualized guest support"
405 Say Y here to get to see options related to running Linux under
406 various hypervisors. This option alone does not add any kernel code.
408 If you say N, all options in this submenu will be skipped and disabled.
412 source "arch/x86/xen/Kconfig"
415 bool "VMI Guest support"
419 VMI provides a paravirtualized interface to the VMware ESX server
420 (it could be used by other hypervisors in theory too, but is not
421 at the moment), by linking the kernel to a GPL-ed ROM module
422 provided by the hypervisor.
425 bool "KVM paravirtualized clock"
427 select PARAVIRT_CLOCK
429 Turning on this option will allow you to run a paravirtualized clock
430 when running over the KVM hypervisor. Instead of relying on a PIT
431 (or probably other) emulation by the underlying device model, the host
432 provides the guest with timing infrastructure such as time of day, and
436 bool "KVM Guest support"
439 This option enables various optimizations for running under the KVM
442 source "arch/x86/lguest/Kconfig"
445 bool "Enable paravirtualization code"
447 This changes the kernel so it can modify itself when it is run
448 under a hypervisor, potentially improving performance significantly
449 over full virtualization. However, when run without a hypervisor
450 the kernel is theoretically slower and slightly larger.
452 config PARAVIRT_CLOCK
458 config PARAVIRT_DEBUG
459 bool "paravirt-ops debugging"
460 depends on PARAVIRT && DEBUG_KERNEL
462 Enable to debug paravirt_ops internals. Specifically, BUG if
463 a paravirt_op is missing when it is called.
468 This option adds a kernel parameter 'memtest', which allows memtest
470 memtest=0, mean disabled; -- default
471 memtest=1, mean do 1 test pattern;
473 memtest=4, mean do 4 test patterns.
474 If you are unsure how to answer this question, answer N.
476 config X86_SUMMIT_NUMA
478 depends on X86_32 && NUMA && X86_32_NON_STANDARD
480 config X86_CYCLONE_TIMER
482 depends on X86_32_NON_STANDARD
484 source "arch/x86/Kconfig.cpu"
488 prompt "HPET Timer Support" if X86_32
490 Use the IA-PC HPET (High Precision Event Timer) to manage
491 time in preference to the PIT and RTC, if a HPET is
493 HPET is the next generation timer replacing legacy 8254s.
494 The HPET provides a stable time base on SMP
495 systems, unlike the TSC, but it is more expensive to access,
496 as it is off-chip. You can find the HPET spec at
497 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
499 You can safely choose Y here. However, HPET will only be
500 activated if the platform and the BIOS support this feature.
501 Otherwise the 8254 will be used for timing services.
503 Choose N to continue using the legacy 8254 timer.
505 config HPET_EMULATE_RTC
507 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
509 # Mark as embedded because too many people got it wrong.
510 # The code disables itself when not needed.
513 bool "Enable DMI scanning" if EMBEDDED
515 Enabled scanning of DMI to identify machine quirks. Say Y
516 here unless you have verified that your setup is not
517 affected by entries in the DMI blacklist. Required by PNP
521 bool "GART IOMMU support" if EMBEDDED
525 depends on X86_64 && PCI
527 Support for full DMA access of devices with 32bit memory access only
528 on systems with more than 3GB. This is usually needed for USB,
529 sound, many IDE/SATA chipsets and some other devices.
530 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
531 based hardware IOMMU and a software bounce buffer based IOMMU used
532 on Intel systems and as fallback.
533 The code is only active when needed (enough memory and limited
534 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
538 bool "IBM Calgary IOMMU support"
540 depends on X86_64 && PCI && EXPERIMENTAL
542 Support for hardware IOMMUs in IBM's xSeries x366 and x460
543 systems. Needed to run systems with more than 3GB of memory
544 properly with 32-bit PCI devices that do not support DAC
545 (Double Address Cycle). Calgary also supports bus level
546 isolation, where all DMAs pass through the IOMMU. This
547 prevents them from going anywhere except their intended
548 destination. This catches hard-to-find kernel bugs and
549 mis-behaving drivers and devices that do not use the DMA-API
550 properly to set up their DMA buffers. The IOMMU can be
551 turned off at boot time with the iommu=off parameter.
552 Normally the kernel will make the right choice by itself.
555 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
557 prompt "Should Calgary be enabled by default?"
558 depends on CALGARY_IOMMU
560 Should Calgary be enabled by default? if you choose 'y', Calgary
561 will be used (if it exists). If you choose 'n', Calgary will not be
562 used even if it exists. If you choose 'n' and would like to use
563 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
567 bool "AMD IOMMU support"
570 depends on X86_64 && PCI && ACPI
572 With this option you can enable support for AMD IOMMU hardware in
573 your system. An IOMMU is a hardware component which provides
574 remapping of DMA memory accesses from devices. With an AMD IOMMU you
575 can isolate the the DMA memory of different devices and protect the
576 system from misbehaving device drivers or hardware.
578 You can find out if your system has an AMD IOMMU if you look into
579 your BIOS for an option to enable it or if you have an IVRS ACPI
582 config AMD_IOMMU_STATS
583 bool "Export AMD IOMMU statistics to debugfs"
587 This option enables code in the AMD IOMMU driver to collect various
588 statistics about whats happening in the driver and exports that
589 information to userspace via debugfs.
592 # need this always selected by IOMMU for the VIA workaround
596 Support for software bounce buffers used on x86-64 systems
597 which don't have a hardware IOMMU (e.g. the current generation
598 of Intel's x86-64 CPUs). Using this PCI devices which can only
599 access 32-bits of memory can be used on systems with more than
600 3 GB of memory. If unsure, say Y.
603 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
606 def_bool (AMD_IOMMU || DMAR)
609 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
610 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
611 select CPUMASK_OFFSTACK
614 Configure maximum number of CPUS and NUMA Nodes for this architecture.
618 int "Maximum number of CPUs" if SMP && !MAXSMP
619 range 2 512 if SMP && !MAXSMP
621 default "4096" if MAXSMP
622 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
625 This allows you to specify the maximum number of CPUs which this
626 kernel will support. The maximum supported value is 512 and the
627 minimum value which makes sense is 2.
629 This is purely to save memory - each supported CPU adds
630 approximately eight kilobytes to the kernel image.
633 bool "SMT (Hyperthreading) scheduler support"
636 SMT scheduler support improves the CPU scheduler's decision making
637 when dealing with Intel Pentium 4 chips with HyperThreading at a
638 cost of slightly increased overhead in some places. If unsure say
643 prompt "Multi-core scheduler support"
646 Multi-core scheduler support improves the CPU scheduler's decision
647 making when dealing with multi-core CPU chips at a cost of slightly
648 increased overhead in some places. If unsure say N here.
650 source "kernel/Kconfig.preempt"
653 bool "Local APIC support on uniprocessors"
654 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
656 A local APIC (Advanced Programmable Interrupt Controller) is an
657 integrated interrupt controller in the CPU. If you have a single-CPU
658 system which has a processor with a local APIC, you can say Y here to
659 enable and use it. If you say Y here even though your machine doesn't
660 have a local APIC, then the kernel will still run with no slowdown at
661 all. The local APIC supports CPU-generated self-interrupts (timer,
662 performance counters), and the NMI watchdog which detects hard
666 bool "IO-APIC support on uniprocessors"
667 depends on X86_UP_APIC
669 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
670 SMP-capable replacement for PC-style interrupt controllers. Most
671 SMP systems and many recent uniprocessor systems have one.
673 If you have a single-CPU system with an IO-APIC, you can say Y here
674 to use it. If you say Y here even though your machine doesn't have
675 an IO-APIC, then the kernel will still run with no slowdown at all.
677 config X86_LOCAL_APIC
679 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
683 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
685 config X86_VISWS_APIC
687 depends on X86_32 && X86_VISWS
689 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
690 bool "Reroute for broken boot IRQs"
692 depends on X86_IO_APIC
694 This option enables a workaround that fixes a source of
695 spurious interrupts. This is recommended when threaded
696 interrupt handling is used on systems where the generation of
697 superfluous "boot interrupts" cannot be disabled.
699 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
700 entry in the chipset's IO-APIC is masked (as, e.g. the RT
701 kernel does during interrupt handling). On chipsets where this
702 boot IRQ generation cannot be disabled, this workaround keeps
703 the original IRQ line masked so that only the equivalent "boot
704 IRQ" is delivered to the CPUs. The workaround also tells the
705 kernel to set up the IRQ handler on the boot IRQ line. In this
706 way only one interrupt is delivered to the kernel. Otherwise
707 the spurious second interrupt may cause the kernel to bring
708 down (vital) interrupt lines.
710 Only affects "broken" chipsets. Interrupt sharing may be
711 increased on these systems.
714 bool "Machine Check Exception"
716 Machine Check Exception support allows the processor to notify the
717 kernel if it detects a problem (e.g. overheating, component failure).
718 The action the kernel takes depends on the severity of the problem,
719 ranging from a warning message on the console, to halting the machine.
720 Your processor must be a Pentium or newer to support this - check the
721 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
722 have a design flaw which leads to false MCE events - hence MCE is
723 disabled on all P5 processors, unless explicitly enabled with "mce"
724 as a boot argument. Similarly, if MCE is built in and creates a
725 problem on some new non-standard machine, you can boot with "nomce"
726 to disable it. MCE support simply ignores non-MCE processors like
727 the 386 and 486, so nearly everyone can say Y here.
731 prompt "Intel MCE features"
732 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
734 Additional support for intel specific MCE features such as
739 prompt "AMD MCE features"
740 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
742 Additional support for AMD specific MCE features such as
743 the DRAM Error Threshold.
745 config X86_MCE_NONFATAL
746 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
747 depends on X86_32 && X86_MCE
749 Enabling this feature starts a timer that triggers every 5 seconds which
750 will look at the machine check registers to see if anything happened.
751 Non-fatal problems automatically get corrected (but still logged).
752 Disable this if you don't want to see these messages.
753 Seeing the messages this option prints out may be indicative of dying
754 or out-of-spec (ie, overclocked) hardware.
755 This option only does something on certain CPUs.
756 (AMD Athlon/Duron and Intel Pentium 4)
758 config X86_MCE_P4THERMAL
759 bool "check for P4 thermal throttling interrupt."
760 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
762 Enabling this feature will cause a message to be printed when the P4
763 enters thermal throttling.
766 bool "Enable VM86 support" if EMBEDDED
770 This option is required by programs like DOSEMU to run 16-bit legacy
771 code on X86 processors. It also may be needed by software like
772 XFree86 to initialize some video cards via BIOS. Disabling this
773 option saves about 6k.
776 tristate "Toshiba Laptop support"
779 This adds a driver to safely access the System Management Mode of
780 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
781 not work on models with a Phoenix BIOS. The System Management Mode
782 is used to set the BIOS and power saving options on Toshiba portables.
784 For information on utilities to make use of this driver see the
785 Toshiba Linux utilities web site at:
786 <http://www.buzzard.org.uk/toshiba/>.
788 Say Y if you intend to run this kernel on a Toshiba portable.
792 tristate "Dell laptop support"
794 This adds a driver to safely access the System Management Mode
795 of the CPU on the Dell Inspiron 8000. The System Management Mode
796 is used to read cpu temperature and cooling fan status and to
797 control the fans on the I8K portables.
799 This driver has been tested only on the Inspiron 8000 but it may
800 also work with other Dell laptops. You can force loading on other
801 models by passing the parameter `force=1' to the module. Use at
804 For information on utilities to make use of this driver see the
805 I8K Linux utilities web site at:
806 <http://people.debian.org/~dz/i8k/>
808 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
811 config X86_REBOOTFIXUPS
812 bool "Enable X86 board specific fixups for reboot"
815 This enables chipset and/or board specific fixups to be done
816 in order to get reboot to work correctly. This is only needed on
817 some combinations of hardware and BIOS. The symptom, for which
818 this config is intended, is when reboot ends with a stalled/hung
821 Currently, the only fixup is for the Geode machines using
822 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
824 Say Y if you want to enable the fixup. Currently, it's safe to
825 enable this option even if you don't need it.
829 tristate "/dev/cpu/microcode - microcode support"
832 If you say Y here, you will be able to update the microcode on
833 certain Intel and AMD processors. The Intel support is for the
834 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
835 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
836 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
837 You will obviously need the actual microcode binary data itself
838 which is not shipped with the Linux kernel.
840 This option selects the general module only, you need to select
841 at least one vendor specific module as well.
843 To compile this driver as a module, choose M here: the
844 module will be called microcode.
846 config MICROCODE_INTEL
847 bool "Intel microcode patch loading support"
852 This options enables microcode patch loading support for Intel
855 For latest news and information on obtaining all the required
856 Intel ingredients for this driver, check:
857 <http://www.urbanmyth.org/microcode/>.
860 bool "AMD microcode patch loading support"
864 If you select this option, microcode patch loading support for AMD
865 processors will be enabled.
867 config MICROCODE_OLD_INTERFACE
872 tristate "/dev/cpu/*/msr - Model-specific register support"
874 This device gives privileged processes access to the x86
875 Model-Specific Registers (MSRs). It is a character device with
876 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
877 MSR accesses are directed to a specific CPU on multi-processor
881 tristate "/dev/cpu/*/cpuid - CPU information support"
883 This device gives processes access to the x86 CPUID instruction to
884 be executed on a specific processor. It is a character device
885 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
889 prompt "High Memory Support"
890 default HIGHMEM4G if !X86_NUMAQ
891 default HIGHMEM64G if X86_NUMAQ
896 depends on !X86_NUMAQ
898 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
899 However, the address space of 32-bit x86 processors is only 4
900 Gigabytes large. That means that, if you have a large amount of
901 physical memory, not all of it can be "permanently mapped" by the
902 kernel. The physical memory that's not permanently mapped is called
905 If you are compiling a kernel which will never run on a machine with
906 more than 1 Gigabyte total physical RAM, answer "off" here (default
907 choice and suitable for most users). This will result in a "3GB/1GB"
908 split: 3GB are mapped so that each process sees a 3GB virtual memory
909 space and the remaining part of the 4GB virtual memory space is used
910 by the kernel to permanently map as much physical memory as
913 If the machine has between 1 and 4 Gigabytes physical RAM, then
916 If more than 4 Gigabytes is used then answer "64GB" here. This
917 selection turns Intel PAE (Physical Address Extension) mode on.
918 PAE implements 3-level paging on IA32 processors. PAE is fully
919 supported by Linux, PAE mode is implemented on all recent Intel
920 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
921 then the kernel will not boot on CPUs that don't support PAE!
923 The actual amount of total physical memory will either be
924 auto detected or can be forced by using a kernel command line option
925 such as "mem=256M". (Try "man bootparam" or see the documentation of
926 your boot loader (lilo or loadlin) about how to pass options to the
927 kernel at boot time.)
929 If unsure, say "off".
933 depends on !X86_NUMAQ
935 Select this if you have a 32-bit processor and between 1 and 4
936 gigabytes of physical RAM.
940 depends on !M386 && !M486
943 Select this if you have a 32-bit processor and more than 4
944 gigabytes of physical RAM.
949 depends on EXPERIMENTAL
950 prompt "Memory split" if EMBEDDED
954 Select the desired split between kernel and user memory.
956 If the address range available to the kernel is less than the
957 physical memory installed, the remaining memory will be available
958 as "high memory". Accessing high memory is a little more costly
959 than low memory, as it needs to be mapped into the kernel first.
960 Note that increasing the kernel address space limits the range
961 available to user programs, making the address space there
962 tighter. Selecting anything other than the default 3G/1G split
963 will also likely make your kernel incompatible with binary-only
966 If you are not absolutely sure what you are doing, leave this
970 bool "3G/1G user/kernel split"
971 config VMSPLIT_3G_OPT
973 bool "3G/1G user/kernel split (for full 1G low memory)"
975 bool "2G/2G user/kernel split"
976 config VMSPLIT_2G_OPT
978 bool "2G/2G user/kernel split (for full 2G low memory)"
980 bool "1G/3G user/kernel split"
985 default 0xB0000000 if VMSPLIT_3G_OPT
986 default 0x80000000 if VMSPLIT_2G
987 default 0x78000000 if VMSPLIT_2G_OPT
988 default 0x40000000 if VMSPLIT_1G
994 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
997 bool "PAE (Physical Address Extension) Support"
998 depends on X86_32 && !HIGHMEM4G
1000 PAE is required for NX support, and furthermore enables
1001 larger swapspace support for non-overcommit purposes. It
1002 has the cost of more pagetable lookup overhead, and also
1003 consumes more pagetable space per process.
1005 config ARCH_PHYS_ADDR_T_64BIT
1006 def_bool X86_64 || X86_PAE
1008 config DIRECT_GBPAGES
1009 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1013 Allow the kernel linear mapping to use 1GB pages on CPUs that
1014 support it. This can improve the kernel's performance a tiny bit by
1015 reducing TLB pressure. If in doubt, say "Y".
1017 # Common NUMA Features
1019 bool "Numa Memory Allocation and Scheduler Support"
1021 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1023 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1025 Enable NUMA (Non Uniform Memory Access) support.
1027 The kernel will try to allocate memory used by a CPU on the
1028 local memory controller of the CPU and add some more
1029 NUMA awareness to the kernel.
1031 For 64-bit this is recommended if the system is Intel Core i7
1032 (or later), AMD Opteron, or EM64T NUMA.
1034 For 32-bit this is only needed on (rare) 32-bit-only platforms
1035 that support NUMA topologies, such as NUMAQ / Summit, or if you
1036 boot a 32-bit kernel on a 64-bit NUMA platform.
1038 Otherwise, you should say N.
1040 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1041 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1045 prompt "Old style AMD Opteron NUMA detection"
1046 depends on X86_64 && NUMA && PCI
1048 Enable K8 NUMA node topology detection. You should say Y here if
1049 you have a multi processor AMD K8 system. This uses an old
1050 method to read the NUMA configuration directly from the builtin
1051 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1052 instead, which also takes priority if both are compiled in.
1054 config X86_64_ACPI_NUMA
1056 prompt "ACPI NUMA detection"
1057 depends on X86_64 && NUMA && ACPI && PCI
1060 Enable ACPI SRAT based node topology detection.
1062 # Some NUMA nodes have memory ranges that span
1063 # other nodes. Even though a pfn is valid and
1064 # between a node's start and end pfns, it may not
1065 # reside on that node. See memmap_init_zone()
1067 config NODES_SPAN_OTHER_NODES
1069 depends on X86_64_ACPI_NUMA
1072 bool "NUMA emulation"
1073 depends on X86_64 && NUMA
1075 Enable NUMA emulation. A flat machine will be split
1076 into virtual nodes when booted with "numa=fake=N", where N is the
1077 number of nodes. This is only useful for debugging.
1080 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1082 default "9" if MAXSMP
1083 default "6" if X86_64
1084 default "4" if X86_NUMAQ
1086 depends on NEED_MULTIPLE_NODES
1088 Specify the maximum number of NUMA Nodes available on the target
1089 system. Increases memory reserved to accomodate various tables.
1091 config HAVE_ARCH_BOOTMEM_NODE
1093 depends on X86_32 && NUMA
1095 config ARCH_HAVE_MEMORY_PRESENT
1097 depends on X86_32 && DISCONTIGMEM
1099 config NEED_NODE_MEMMAP_SIZE
1101 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1103 config HAVE_ARCH_ALLOC_REMAP
1105 depends on X86_32 && NUMA
1107 config ARCH_FLATMEM_ENABLE
1109 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1111 config ARCH_DISCONTIGMEM_ENABLE
1113 depends on NUMA && X86_32
1115 config ARCH_DISCONTIGMEM_DEFAULT
1117 depends on NUMA && X86_32
1119 config ARCH_SPARSEMEM_DEFAULT
1123 config ARCH_SPARSEMEM_ENABLE
1125 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_32_NON_STANDARD
1126 select SPARSEMEM_STATIC if X86_32
1127 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1129 config ARCH_SELECT_MEMORY_MODEL
1131 depends on ARCH_SPARSEMEM_ENABLE
1133 config ARCH_MEMORY_PROBE
1135 depends on MEMORY_HOTPLUG
1140 bool "Allocate 3rd-level pagetables from highmem"
1141 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1143 The VM uses one page table entry for each page of physical memory.
1144 For systems with a lot of RAM, this can be wasteful of precious
1145 low memory. Setting this option will put user-space page table
1146 entries in high memory.
1148 config X86_CHECK_BIOS_CORRUPTION
1149 bool "Check for low memory corruption"
1151 Periodically check for memory corruption in low memory, which
1152 is suspected to be caused by BIOS. Even when enabled in the
1153 configuration, it is disabled at runtime. Enable it by
1154 setting "memory_corruption_check=1" on the kernel command
1155 line. By default it scans the low 64k of memory every 60
1156 seconds; see the memory_corruption_check_size and
1157 memory_corruption_check_period parameters in
1158 Documentation/kernel-parameters.txt to adjust this.
1160 When enabled with the default parameters, this option has
1161 almost no overhead, as it reserves a relatively small amount
1162 of memory and scans it infrequently. It both detects corruption
1163 and prevents it from affecting the running system.
1165 It is, however, intended as a diagnostic tool; if repeatable
1166 BIOS-originated corruption always affects the same memory,
1167 you can use memmap= to prevent the kernel from using that
1170 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1171 bool "Set the default setting of memory_corruption_check"
1172 depends on X86_CHECK_BIOS_CORRUPTION
1175 Set whether the default state of memory_corruption_check is
1178 config X86_RESERVE_LOW_64K
1179 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1182 Reserve the first 64K of physical RAM on BIOSes that are known
1183 to potentially corrupt that memory range. A numbers of BIOSes are
1184 known to utilize this area during suspend/resume, so it must not
1185 be used by the kernel.
1187 Set this to N if you are absolutely sure that you trust the BIOS
1188 to get all its memory reservations and usages right.
1190 If you have doubts about the BIOS (e.g. suspend/resume does not
1191 work or there's kernel crashes after certain hardware hotplug
1192 events) and it's not AMI or Phoenix, then you might want to enable
1193 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1194 corruption patterns.
1198 config MATH_EMULATION
1200 prompt "Math emulation" if X86_32
1202 Linux can emulate a math coprocessor (used for floating point
1203 operations) if you don't have one. 486DX and Pentium processors have
1204 a math coprocessor built in, 486SX and 386 do not, unless you added
1205 a 487DX or 387, respectively. (The messages during boot time can
1206 give you some hints here ["man dmesg"].) Everyone needs either a
1207 coprocessor or this emulation.
1209 If you don't have a math coprocessor, you need to say Y here; if you
1210 say Y here even though you have a coprocessor, the coprocessor will
1211 be used nevertheless. (This behavior can be changed with the kernel
1212 command line option "no387", which comes handy if your coprocessor
1213 is broken. Try "man bootparam" or see the documentation of your boot
1214 loader (lilo or loadlin) about how to pass options to the kernel at
1215 boot time.) This means that it is a good idea to say Y here if you
1216 intend to use this kernel on different machines.
1218 More information about the internals of the Linux math coprocessor
1219 emulation can be found in <file:arch/x86/math-emu/README>.
1221 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1222 kernel, it won't hurt.
1225 bool "MTRR (Memory Type Range Register) support"
1227 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1228 the Memory Type Range Registers (MTRRs) may be used to control
1229 processor access to memory ranges. This is most useful if you have
1230 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1231 allows bus write transfers to be combined into a larger transfer
1232 before bursting over the PCI/AGP bus. This can increase performance
1233 of image write operations 2.5 times or more. Saying Y here creates a
1234 /proc/mtrr file which may be used to manipulate your processor's
1235 MTRRs. Typically the X server should use this.
1237 This code has a reasonably generic interface so that similar
1238 control registers on other processors can be easily supported
1241 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1242 Registers (ARRs) which provide a similar functionality to MTRRs. For
1243 these, the ARRs are used to emulate the MTRRs.
1244 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1245 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1246 write-combining. All of these processors are supported by this code
1247 and it makes sense to say Y here if you have one of them.
1249 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1250 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1251 can lead to all sorts of problems, so it's good to say Y here.
1253 You can safely say Y even if your machine doesn't have MTRRs, you'll
1254 just add about 9 KB to your kernel.
1256 See <file:Documentation/x86/mtrr.txt> for more information.
1258 config MTRR_SANITIZER
1260 prompt "MTRR cleanup support"
1263 Convert MTRR layout from continuous to discrete, so X drivers can
1264 add writeback entries.
1266 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1267 The largest mtrr entry size for a continous block can be set with
1272 config MTRR_SANITIZER_ENABLE_DEFAULT
1273 int "MTRR cleanup enable value (0-1)"
1276 depends on MTRR_SANITIZER
1278 Enable mtrr cleanup default value
1280 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1281 int "MTRR cleanup spare reg num (0-7)"
1284 depends on MTRR_SANITIZER
1286 mtrr cleanup spare entries default, it can be changed via
1287 mtrr_spare_reg_nr=N on the kernel command line.
1291 prompt "x86 PAT support"
1294 Use PAT attributes to setup page level cache control.
1296 PATs are the modern equivalents of MTRRs and are much more
1297 flexible than MTRRs.
1299 Say N here if you see bootup problems (boot crash, boot hang,
1300 spontaneous reboots) or a non-working video driver.
1305 bool "EFI runtime service support"
1308 This enables the kernel to use EFI runtime services that are
1309 available (such as the EFI variable services).
1311 This option is only useful on systems that have EFI firmware.
1312 In addition, you should use the latest ELILO loader available
1313 at <http://elilo.sourceforge.net> in order to take advantage
1314 of EFI runtime services. However, even with this option, the
1315 resultant kernel should continue to boot on existing non-EFI
1320 prompt "Enable seccomp to safely compute untrusted bytecode"
1322 This kernel feature is useful for number crunching applications
1323 that may need to compute untrusted bytecode during their
1324 execution. By using pipes or other transports made available to
1325 the process as file descriptors supporting the read/write
1326 syscalls, it's possible to isolate those applications in
1327 their own address space using seccomp. Once seccomp is
1328 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1329 and the task is only allowed to execute a few safe syscalls
1330 defined by each seccomp mode.
1332 If unsure, say Y. Only embedded should say N here.
1334 config CC_STACKPROTECTOR_ALL
1337 config CC_STACKPROTECTOR
1338 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1340 select CC_STACKPROTECTOR_ALL
1342 This option turns on the -fstack-protector GCC feature. This
1343 feature puts, at the beginning of functions, a canary value on
1344 the stack just before the return address, and validates
1345 the value just before actually returning. Stack based buffer
1346 overflows (that need to overwrite this return address) now also
1347 overwrite the canary, which gets detected and the attack is then
1348 neutralized via a kernel panic.
1350 This feature requires gcc version 4.2 or above, or a distribution
1351 gcc with the feature backported. Older versions are automatically
1352 detected and for those versions, this configuration option is
1353 ignored. (and a warning is printed during bootup)
1355 source kernel/Kconfig.hz
1358 bool "kexec system call"
1360 kexec is a system call that implements the ability to shutdown your
1361 current kernel, and to start another kernel. It is like a reboot
1362 but it is independent of the system firmware. And like a reboot
1363 you can start any kernel with it, not just Linux.
1365 The name comes from the similarity to the exec system call.
1367 It is an ongoing process to be certain the hardware in a machine
1368 is properly shutdown, so do not be surprised if this code does not
1369 initially work for you. It may help to enable device hotplugging
1370 support. As of this writing the exact hardware interface is
1371 strongly in flux, so no good recommendation can be made.
1374 bool "kernel crash dumps"
1375 depends on X86_64 || (X86_32 && HIGHMEM)
1377 Generate crash dump after being started by kexec.
1378 This should be normally only set in special crash dump kernels
1379 which are loaded in the main kernel with kexec-tools into
1380 a specially reserved region and then later executed after
1381 a crash by kdump/kexec. The crash dump kernel must be compiled
1382 to a memory address not used by the main kernel or BIOS using
1383 PHYSICAL_START, or it must be built as a relocatable image
1384 (CONFIG_RELOCATABLE=y).
1385 For more details see Documentation/kdump/kdump.txt
1388 bool "kexec jump (EXPERIMENTAL)"
1389 depends on EXPERIMENTAL
1390 depends on KEXEC && HIBERNATION && X86_32
1392 Jump between original kernel and kexeced kernel and invoke
1393 code in physical address mode via KEXEC
1395 config PHYSICAL_START
1396 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1397 default "0x1000000" if X86_NUMAQ
1398 default "0x200000" if X86_64
1401 This gives the physical address where the kernel is loaded.
1403 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1404 bzImage will decompress itself to above physical address and
1405 run from there. Otherwise, bzImage will run from the address where
1406 it has been loaded by the boot loader and will ignore above physical
1409 In normal kdump cases one does not have to set/change this option
1410 as now bzImage can be compiled as a completely relocatable image
1411 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1412 address. This option is mainly useful for the folks who don't want
1413 to use a bzImage for capturing the crash dump and want to use a
1414 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1415 to be specifically compiled to run from a specific memory area
1416 (normally a reserved region) and this option comes handy.
1418 So if you are using bzImage for capturing the crash dump, leave
1419 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1420 Otherwise if you plan to use vmlinux for capturing the crash dump
1421 change this value to start of the reserved region (Typically 16MB
1422 0x1000000). In other words, it can be set based on the "X" value as
1423 specified in the "crashkernel=YM@XM" command line boot parameter
1424 passed to the panic-ed kernel. Typically this parameter is set as
1425 crashkernel=64M@16M. Please take a look at
1426 Documentation/kdump/kdump.txt for more details about crash dumps.
1428 Usage of bzImage for capturing the crash dump is recommended as
1429 one does not have to build two kernels. Same kernel can be used
1430 as production kernel and capture kernel. Above option should have
1431 gone away after relocatable bzImage support is introduced. But it
1432 is present because there are users out there who continue to use
1433 vmlinux for dump capture. This option should go away down the
1436 Don't change this unless you know what you are doing.
1439 bool "Build a relocatable kernel (EXPERIMENTAL)"
1440 depends on EXPERIMENTAL
1442 This builds a kernel image that retains relocation information
1443 so it can be loaded someplace besides the default 1MB.
1444 The relocations tend to make the kernel binary about 10% larger,
1445 but are discarded at runtime.
1447 One use is for the kexec on panic case where the recovery kernel
1448 must live at a different physical address than the primary
1451 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1452 it has been loaded at and the compile time physical address
1453 (CONFIG_PHYSICAL_START) is ignored.
1455 config PHYSICAL_ALIGN
1457 prompt "Alignment value to which kernel should be aligned" if X86_32
1458 default "0x100000" if X86_32
1459 default "0x200000" if X86_64
1460 range 0x2000 0x400000
1462 This value puts the alignment restrictions on physical address
1463 where kernel is loaded and run from. Kernel is compiled for an
1464 address which meets above alignment restriction.
1466 If bootloader loads the kernel at a non-aligned address and
1467 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1468 address aligned to above value and run from there.
1470 If bootloader loads the kernel at a non-aligned address and
1471 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1472 load address and decompress itself to the address it has been
1473 compiled for and run from there. The address for which kernel is
1474 compiled already meets above alignment restrictions. Hence the
1475 end result is that kernel runs from a physical address meeting
1476 above alignment restrictions.
1478 Don't change this unless you know what you are doing.
1481 bool "Support for hot-pluggable CPUs"
1482 depends on SMP && HOTPLUG
1484 Say Y here to allow turning CPUs off and on. CPUs can be
1485 controlled through /sys/devices/system/cpu.
1486 ( Note: power management support will enable this option
1487 automatically on SMP systems. )
1488 Say N if you want to disable CPU hotplug.
1492 prompt "Compat VDSO support"
1493 depends on X86_32 || IA32_EMULATION
1495 Map the 32-bit VDSO to the predictable old-style address too.
1497 Say N here if you are running a sufficiently recent glibc
1498 version (2.3.3 or later), to remove the high-mapped
1499 VDSO mapping and to exclusively use the randomized VDSO.
1504 bool "Built-in kernel command line"
1507 Allow for specifying boot arguments to the kernel at
1508 build time. On some systems (e.g. embedded ones), it is
1509 necessary or convenient to provide some or all of the
1510 kernel boot arguments with the kernel itself (that is,
1511 to not rely on the boot loader to provide them.)
1513 To compile command line arguments into the kernel,
1514 set this option to 'Y', then fill in the
1515 the boot arguments in CONFIG_CMDLINE.
1517 Systems with fully functional boot loaders (i.e. non-embedded)
1518 should leave this option set to 'N'.
1521 string "Built-in kernel command string"
1522 depends on CMDLINE_BOOL
1525 Enter arguments here that should be compiled into the kernel
1526 image and used at boot time. If the boot loader provides a
1527 command line at boot time, it is appended to this string to
1528 form the full kernel command line, when the system boots.
1530 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1531 change this behavior.
1533 In most cases, the command line (whether built-in or provided
1534 by the boot loader) should specify the device for the root
1537 config CMDLINE_OVERRIDE
1538 bool "Built-in command line overrides boot loader arguments"
1540 depends on CMDLINE_BOOL
1542 Set this option to 'Y' to have the kernel ignore the boot loader
1543 command line, and use ONLY the built-in command line.
1545 This is used to work around broken boot loaders. This should
1546 be set to 'N' under normal conditions.
1550 config ARCH_ENABLE_MEMORY_HOTPLUG
1552 depends on X86_64 || (X86_32 && HIGHMEM)
1554 config ARCH_ENABLE_MEMORY_HOTREMOVE
1556 depends on MEMORY_HOTPLUG
1558 config HAVE_ARCH_EARLY_PFN_TO_NID
1562 menu "Power management and ACPI options"
1564 config ARCH_HIBERNATION_HEADER
1566 depends on X86_64 && HIBERNATION
1568 source "kernel/power/Kconfig"
1570 source "drivers/acpi/Kconfig"
1575 depends on APM || APM_MODULE
1578 tristate "APM (Advanced Power Management) BIOS support"
1579 depends on X86_32 && PM_SLEEP
1581 APM is a BIOS specification for saving power using several different
1582 techniques. This is mostly useful for battery powered laptops with
1583 APM compliant BIOSes. If you say Y here, the system time will be
1584 reset after a RESUME operation, the /proc/apm device will provide
1585 battery status information, and user-space programs will receive
1586 notification of APM "events" (e.g. battery status change).
1588 If you select "Y" here, you can disable actual use of the APM
1589 BIOS by passing the "apm=off" option to the kernel at boot time.
1591 Note that the APM support is almost completely disabled for
1592 machines with more than one CPU.
1594 In order to use APM, you will need supporting software. For location
1595 and more information, read <file:Documentation/power/pm.txt> and the
1596 Battery Powered Linux mini-HOWTO, available from
1597 <http://www.tldp.org/docs.html#howto>.
1599 This driver does not spin down disk drives (see the hdparm(8)
1600 manpage ("man 8 hdparm") for that), and it doesn't turn off
1601 VESA-compliant "green" monitors.
1603 This driver does not support the TI 4000M TravelMate and the ACER
1604 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1605 desktop machines also don't have compliant BIOSes, and this driver
1606 may cause those machines to panic during the boot phase.
1608 Generally, if you don't have a battery in your machine, there isn't
1609 much point in using this driver and you should say N. If you get
1610 random kernel OOPSes or reboots that don't seem to be related to
1611 anything, try disabling/enabling this option (or disabling/enabling
1614 Some other things you should try when experiencing seemingly random,
1617 1) make sure that you have enough swap space and that it is
1619 2) pass the "no-hlt" option to the kernel
1620 3) switch on floating point emulation in the kernel and pass
1621 the "no387" option to the kernel
1622 4) pass the "floppy=nodma" option to the kernel
1623 5) pass the "mem=4M" option to the kernel (thereby disabling
1624 all but the first 4 MB of RAM)
1625 6) make sure that the CPU is not over clocked.
1626 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1627 8) disable the cache from your BIOS settings
1628 9) install a fan for the video card or exchange video RAM
1629 10) install a better fan for the CPU
1630 11) exchange RAM chips
1631 12) exchange the motherboard.
1633 To compile this driver as a module, choose M here: the
1634 module will be called apm.
1638 config APM_IGNORE_USER_SUSPEND
1639 bool "Ignore USER SUSPEND"
1641 This option will ignore USER SUSPEND requests. On machines with a
1642 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1643 series notebooks, it is necessary to say Y because of a BIOS bug.
1645 config APM_DO_ENABLE
1646 bool "Enable PM at boot time"
1648 Enable APM features at boot time. From page 36 of the APM BIOS
1649 specification: "When disabled, the APM BIOS does not automatically
1650 power manage devices, enter the Standby State, enter the Suspend
1651 State, or take power saving steps in response to CPU Idle calls."
1652 This driver will make CPU Idle calls when Linux is idle (unless this
1653 feature is turned off -- see "Do CPU IDLE calls", below). This
1654 should always save battery power, but more complicated APM features
1655 will be dependent on your BIOS implementation. You may need to turn
1656 this option off if your computer hangs at boot time when using APM
1657 support, or if it beeps continuously instead of suspending. Turn
1658 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1659 T400CDT. This is off by default since most machines do fine without
1663 bool "Make CPU Idle calls when idle"
1665 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1666 On some machines, this can activate improved power savings, such as
1667 a slowed CPU clock rate, when the machine is idle. These idle calls
1668 are made after the idle loop has run for some length of time (e.g.,
1669 333 mS). On some machines, this will cause a hang at boot time or
1670 whenever the CPU becomes idle. (On machines with more than one CPU,
1671 this option does nothing.)
1673 config APM_DISPLAY_BLANK
1674 bool "Enable console blanking using APM"
1676 Enable console blanking using the APM. Some laptops can use this to
1677 turn off the LCD backlight when the screen blanker of the Linux
1678 virtual console blanks the screen. Note that this is only used by
1679 the virtual console screen blanker, and won't turn off the backlight
1680 when using the X Window system. This also doesn't have anything to
1681 do with your VESA-compliant power-saving monitor. Further, this
1682 option doesn't work for all laptops -- it might not turn off your
1683 backlight at all, or it might print a lot of errors to the console,
1684 especially if you are using gpm.
1686 config APM_ALLOW_INTS
1687 bool "Allow interrupts during APM BIOS calls"
1689 Normally we disable external interrupts while we are making calls to
1690 the APM BIOS as a measure to lessen the effects of a badly behaving
1691 BIOS implementation. The BIOS should reenable interrupts if it
1692 needs to. Unfortunately, some BIOSes do not -- especially those in
1693 many of the newer IBM Thinkpads. If you experience hangs when you
1694 suspend, try setting this to Y. Otherwise, say N.
1698 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1700 source "drivers/cpuidle/Kconfig"
1702 source "drivers/idle/Kconfig"
1707 menu "Bus options (PCI etc.)"
1712 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1714 Find out whether you have a PCI motherboard. PCI is the name of a
1715 bus system, i.e. the way the CPU talks to the other stuff inside
1716 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1717 VESA. If you have PCI, say Y, otherwise N.
1720 prompt "PCI access mode"
1721 depends on X86_32 && PCI
1724 On PCI systems, the BIOS can be used to detect the PCI devices and
1725 determine their configuration. However, some old PCI motherboards
1726 have BIOS bugs and may crash if this is done. Also, some embedded
1727 PCI-based systems don't have any BIOS at all. Linux can also try to
1728 detect the PCI hardware directly without using the BIOS.
1730 With this option, you can specify how Linux should detect the
1731 PCI devices. If you choose "BIOS", the BIOS will be used,
1732 if you choose "Direct", the BIOS won't be used, and if you
1733 choose "MMConfig", then PCI Express MMCONFIG will be used.
1734 If you choose "Any", the kernel will try MMCONFIG, then the
1735 direct access method and falls back to the BIOS if that doesn't
1736 work. If unsure, go with the default, which is "Any".
1741 config PCI_GOMMCONFIG
1758 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1760 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1763 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1767 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1771 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1778 bool "Support mmconfig PCI config space access"
1779 depends on X86_64 && PCI && ACPI
1782 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1783 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1785 DMA remapping (DMAR) devices support enables independent address
1786 translations for Direct Memory Access (DMA) from devices.
1787 These DMA remapping devices are reported via ACPI tables
1788 and include PCI device scope covered by these DMA
1793 prompt "Support for Graphics workaround"
1796 Current Graphics drivers tend to use physical address
1797 for DMA and avoid using DMA APIs. Setting this config
1798 option permits the IOMMU driver to set a unity map for
1799 all the OS-visible memory. Hence the driver can continue
1800 to use physical addresses for DMA.
1802 config DMAR_FLOPPY_WA
1806 Floppy disk drivers are know to bypass DMA API calls
1807 thereby failing to work when IOMMU is enabled. This
1808 workaround will setup a 1:1 mapping for the first
1809 16M to make floppy (an ISA device) work.
1812 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1813 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1815 Supports Interrupt remapping for IO-APIC and MSI devices.
1816 To use x2apic mode in the CPU's which support x2APIC enhancements or
1817 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1819 source "drivers/pci/pcie/Kconfig"
1821 source "drivers/pci/Kconfig"
1823 # x86_64 have no ISA slots, but do have ISA-style DMA.
1832 Find out whether you have ISA slots on your motherboard. ISA is the
1833 name of a bus system, i.e. the way the CPU talks to the other stuff
1834 inside your box. Other bus systems are PCI, EISA, MicroChannel
1835 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1836 newer boards don't support it. If you have ISA, say Y, otherwise N.
1842 The Extended Industry Standard Architecture (EISA) bus was
1843 developed as an open alternative to the IBM MicroChannel bus.
1845 The EISA bus provided some of the features of the IBM MicroChannel
1846 bus while maintaining backward compatibility with cards made for
1847 the older ISA bus. The EISA bus saw limited use between 1988 and
1848 1995 when it was made obsolete by the PCI bus.
1850 Say Y here if you are building a kernel for an EISA-based machine.
1854 source "drivers/eisa/Kconfig"
1859 MicroChannel Architecture is found in some IBM PS/2 machines and
1860 laptops. It is a bus system similar to PCI or ISA. See
1861 <file:Documentation/mca.txt> (and especially the web page given
1862 there) before attempting to build an MCA bus kernel.
1864 source "drivers/mca/Kconfig"
1867 tristate "NatSemi SCx200 support"
1869 This provides basic support for National Semiconductor's
1870 (now AMD's) Geode processors. The driver probes for the
1871 PCI-IDs of several on-chip devices, so its a good dependency
1872 for other scx200_* drivers.
1874 If compiled as a module, the driver is named scx200.
1876 config SCx200HR_TIMER
1877 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1878 depends on SCx200 && GENERIC_TIME
1881 This driver provides a clocksource built upon the on-chip
1882 27MHz high-resolution timer. Its also a workaround for
1883 NSC Geode SC-1100's buggy TSC, which loses time when the
1884 processor goes idle (as is done by the scheduler). The
1885 other workaround is idle=poll boot option.
1887 config GEODE_MFGPT_TIMER
1889 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1890 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1892 This driver provides a clock event source based on the MFGPT
1893 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1894 MFGPTs have a better resolution and max interval than the
1895 generic PIT, and are suitable for use as high-res timers.
1898 bool "One Laptop Per Child support"
1901 Add support for detecting the unique features of the OLPC
1908 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1910 source "drivers/pcmcia/Kconfig"
1912 source "drivers/pci/hotplug/Kconfig"
1917 menu "Executable file formats / Emulations"
1919 source "fs/Kconfig.binfmt"
1921 config IA32_EMULATION
1922 bool "IA32 Emulation"
1924 select COMPAT_BINFMT_ELF
1926 Include code to run 32-bit programs under a 64-bit kernel. You should
1927 likely turn this on, unless you're 100% sure that you don't have any
1928 32-bit programs left.
1931 tristate "IA32 a.out support"
1932 depends on IA32_EMULATION
1934 Support old a.out binaries in the 32bit emulation.
1938 depends on IA32_EMULATION
1940 config COMPAT_FOR_U64_ALIGNMENT
1944 config SYSVIPC_COMPAT
1946 depends on COMPAT && SYSVIPC
1951 config HAVE_ATOMIC_IOMAP
1955 source "net/Kconfig"
1957 source "drivers/Kconfig"
1959 source "drivers/firmware/Kconfig"
1963 source "arch/x86/Kconfig.debug"
1965 source "security/Kconfig"
1967 source "crypto/Kconfig"
1969 source "arch/x86/kvm/Kconfig"
1971 source "lib/Kconfig"
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