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
265 config X86_NON_STANDARD
266 bool "Support for non-standard x86 platforms"
268 If you disable this option then the kernel will only support
269 standard PC platforms. (which covers the vast majority of
272 If you enable this option then you'll be able to select a number
273 of less common non-PC x86 platforms: VisWS, RDC321, SGI/UV.
275 If you have one of these systems, or if you want to build a
276 generic distribution kernel, say Y here - otherwise say N.
279 bool "SGI 320/540 (Visual Workstation)"
280 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
281 depends on X86_NON_STANDARD
283 The SGI Visual Workstation series is an IA32-based workstation
284 based on SGI systems chips with some legacy PC hardware attached.
286 Say Y here to create a kernel to run on the SGI 320 or 540.
288 A kernel compiled for the Visual Workstation will run on general
289 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
292 bool "RDC R-321x SoC"
294 depends on X86_NON_STANDARD
296 select X86_REBOOTFIXUPS
298 This option is needed for RDC R-321x system-on-chip, also known
300 If you don't have one of these chips, you should say N here.
303 bool "SGI Ultraviolet"
305 depends on X86_NON_STANDARD
307 This option is needed in order to support SGI Ultraviolet systems.
308 If you don't have one of these, you should say N here.
311 bool "Support for ScaleMP vSMP"
313 depends on X86_64 && PCI
314 depends on X86_NON_STANDARD
316 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
317 supposed to run on these EM64T-based machines. Only choose this option
318 if you have one of these machines.
323 depends on X86_NON_STANDARD
325 Select this for an AMD Elan processor.
327 Do not use this option for K6/Athlon/Opteron processors!
329 If unsure, choose "PC-compatible" instead.
331 config X86_32_NON_STANDARD
332 bool "Support non-standard 32-bit SMP architectures"
333 depends on X86_32 && SMP
334 depends on X86_NON_STANDARD
336 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
337 subarchitectures. It is intended for a generic binary kernel.
338 if you select them all, kernel will probe it one by one. and will
342 bool "Support for big SMP systems with more than 8 CPUs"
343 depends on X86_32_NON_STANDARD
345 This option is needed for the systems that have more than 8 CPUs
346 and if the system is not of any sub-arch type above.
349 bool "NUMAQ (IBM/Sequent)"
350 depends on X86_32_NON_STANDARD
354 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
355 NUMA multiquad box. This changes the way that processors are
356 bootstrapped, and uses Clustered Logical APIC addressing mode instead
357 of Flat Logical. You will need a new lynxer.elf file to flash your
358 firmware with - send email to <Martin.Bligh@us.ibm.com>.
361 bool "Summit/EXA (IBM x440)"
362 depends on X86_32_NON_STANDARD
364 This option is needed for IBM systems that use the Summit/EXA chipset.
365 In particular, it is needed for the x440.
368 bool "Support for Unisys ES7000 IA32 series"
369 depends on X86_32_NON_STANDARD
371 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
372 supposed to run on an IA32-based Unisys ES7000 system.
376 depends on SMP && !PCI && BROKEN
377 depends on X86_32_NON_STANDARD
379 Voyager is an MCA-based 32-way capable SMP architecture proprietary
380 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
384 If you do not specifically know you have a Voyager based machine,
385 say N here, otherwise the kernel you build will not be bootable.
387 config SCHED_OMIT_FRAME_POINTER
389 prompt "Single-depth WCHAN output"
392 Calculate simpler /proc/<PID>/wchan values. If this option
393 is disabled then wchan values will recurse back to the
394 caller function. This provides more accurate wchan values,
395 at the expense of slightly more scheduling overhead.
397 If in doubt, say "Y".
399 menuconfig PARAVIRT_GUEST
400 bool "Paravirtualized guest support"
402 Say Y here to get to see options related to running Linux under
403 various hypervisors. This option alone does not add any kernel code.
405 If you say N, all options in this submenu will be skipped and disabled.
409 source "arch/x86/xen/Kconfig"
412 bool "VMI Guest support"
416 VMI provides a paravirtualized interface to the VMware ESX server
417 (it could be used by other hypervisors in theory too, but is not
418 at the moment), by linking the kernel to a GPL-ed ROM module
419 provided by the hypervisor.
422 bool "KVM paravirtualized clock"
424 select PARAVIRT_CLOCK
426 Turning on this option will allow you to run a paravirtualized clock
427 when running over the KVM hypervisor. Instead of relying on a PIT
428 (or probably other) emulation by the underlying device model, the host
429 provides the guest with timing infrastructure such as time of day, and
433 bool "KVM Guest support"
436 This option enables various optimizations for running under the KVM
439 source "arch/x86/lguest/Kconfig"
442 bool "Enable paravirtualization code"
444 This changes the kernel so it can modify itself when it is run
445 under a hypervisor, potentially improving performance significantly
446 over full virtualization. However, when run without a hypervisor
447 the kernel is theoretically slower and slightly larger.
449 config PARAVIRT_CLOCK
455 config PARAVIRT_DEBUG
456 bool "paravirt-ops debugging"
457 depends on PARAVIRT && DEBUG_KERNEL
459 Enable to debug paravirt_ops internals. Specifically, BUG if
460 a paravirt_op is missing when it is called.
465 This option adds a kernel parameter 'memtest', which allows memtest
467 memtest=0, mean disabled; -- default
468 memtest=1, mean do 1 test pattern;
470 memtest=4, mean do 4 test patterns.
471 If you are unsure how to answer this question, answer N.
473 config X86_SUMMIT_NUMA
475 depends on X86_32 && NUMA && X86_32_NON_STANDARD
477 config X86_CYCLONE_TIMER
479 depends on X86_32_NON_STANDARD
481 source "arch/x86/Kconfig.cpu"
485 prompt "HPET Timer Support" if X86_32
487 Use the IA-PC HPET (High Precision Event Timer) to manage
488 time in preference to the PIT and RTC, if a HPET is
490 HPET is the next generation timer replacing legacy 8254s.
491 The HPET provides a stable time base on SMP
492 systems, unlike the TSC, but it is more expensive to access,
493 as it is off-chip. You can find the HPET spec at
494 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
496 You can safely choose Y here. However, HPET will only be
497 activated if the platform and the BIOS support this feature.
498 Otherwise the 8254 will be used for timing services.
500 Choose N to continue using the legacy 8254 timer.
502 config HPET_EMULATE_RTC
504 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506 # Mark as embedded because too many people got it wrong.
507 # The code disables itself when not needed.
510 bool "Enable DMI scanning" if EMBEDDED
512 Enabled scanning of DMI to identify machine quirks. Say Y
513 here unless you have verified that your setup is not
514 affected by entries in the DMI blacklist. Required by PNP
518 bool "GART IOMMU support" if EMBEDDED
522 depends on X86_64 && PCI
524 Support for full DMA access of devices with 32bit memory access only
525 on systems with more than 3GB. This is usually needed for USB,
526 sound, many IDE/SATA chipsets and some other devices.
527 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
528 based hardware IOMMU and a software bounce buffer based IOMMU used
529 on Intel systems and as fallback.
530 The code is only active when needed (enough memory and limited
531 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
535 bool "IBM Calgary IOMMU support"
537 depends on X86_64 && PCI && EXPERIMENTAL
539 Support for hardware IOMMUs in IBM's xSeries x366 and x460
540 systems. Needed to run systems with more than 3GB of memory
541 properly with 32-bit PCI devices that do not support DAC
542 (Double Address Cycle). Calgary also supports bus level
543 isolation, where all DMAs pass through the IOMMU. This
544 prevents them from going anywhere except their intended
545 destination. This catches hard-to-find kernel bugs and
546 mis-behaving drivers and devices that do not use the DMA-API
547 properly to set up their DMA buffers. The IOMMU can be
548 turned off at boot time with the iommu=off parameter.
549 Normally the kernel will make the right choice by itself.
552 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
554 prompt "Should Calgary be enabled by default?"
555 depends on CALGARY_IOMMU
557 Should Calgary be enabled by default? if you choose 'y', Calgary
558 will be used (if it exists). If you choose 'n', Calgary will not be
559 used even if it exists. If you choose 'n' and would like to use
560 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
564 bool "AMD IOMMU support"
567 depends on X86_64 && PCI && ACPI
569 With this option you can enable support for AMD IOMMU hardware in
570 your system. An IOMMU is a hardware component which provides
571 remapping of DMA memory accesses from devices. With an AMD IOMMU you
572 can isolate the the DMA memory of different devices and protect the
573 system from misbehaving device drivers or hardware.
575 You can find out if your system has an AMD IOMMU if you look into
576 your BIOS for an option to enable it or if you have an IVRS ACPI
579 config AMD_IOMMU_STATS
580 bool "Export AMD IOMMU statistics to debugfs"
584 This option enables code in the AMD IOMMU driver to collect various
585 statistics about whats happening in the driver and exports that
586 information to userspace via debugfs.
589 # need this always selected by IOMMU for the VIA workaround
593 Support for software bounce buffers used on x86-64 systems
594 which don't have a hardware IOMMU (e.g. the current generation
595 of Intel's x86-64 CPUs). Using this PCI devices which can only
596 access 32-bits of memory can be used on systems with more than
597 3 GB of memory. If unsure, say Y.
600 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
603 def_bool (AMD_IOMMU || DMAR)
606 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
607 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
608 select CPUMASK_OFFSTACK
611 Configure maximum number of CPUS and NUMA Nodes for this architecture.
615 int "Maximum number of CPUs" if SMP && !MAXSMP
616 range 2 512 if SMP && !MAXSMP
618 default "4096" if MAXSMP
619 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
622 This allows you to specify the maximum number of CPUs which this
623 kernel will support. The maximum supported value is 512 and the
624 minimum value which makes sense is 2.
626 This is purely to save memory - each supported CPU adds
627 approximately eight kilobytes to the kernel image.
630 bool "SMT (Hyperthreading) scheduler support"
633 SMT scheduler support improves the CPU scheduler's decision making
634 when dealing with Intel Pentium 4 chips with HyperThreading at a
635 cost of slightly increased overhead in some places. If unsure say
640 prompt "Multi-core scheduler support"
643 Multi-core scheduler support improves the CPU scheduler's decision
644 making when dealing with multi-core CPU chips at a cost of slightly
645 increased overhead in some places. If unsure say N here.
647 source "kernel/Kconfig.preempt"
650 bool "Local APIC support on uniprocessors"
651 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
653 A local APIC (Advanced Programmable Interrupt Controller) is an
654 integrated interrupt controller in the CPU. If you have a single-CPU
655 system which has a processor with a local APIC, you can say Y here to
656 enable and use it. If you say Y here even though your machine doesn't
657 have a local APIC, then the kernel will still run with no slowdown at
658 all. The local APIC supports CPU-generated self-interrupts (timer,
659 performance counters), and the NMI watchdog which detects hard
663 bool "IO-APIC support on uniprocessors"
664 depends on X86_UP_APIC
666 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
667 SMP-capable replacement for PC-style interrupt controllers. Most
668 SMP systems and many recent uniprocessor systems have one.
670 If you have a single-CPU system with an IO-APIC, you can say Y here
671 to use it. If you say Y here even though your machine doesn't have
672 an IO-APIC, then the kernel will still run with no slowdown at all.
674 config X86_LOCAL_APIC
676 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
680 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
682 config X86_VISWS_APIC
684 depends on X86_32 && X86_VISWS
686 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
687 bool "Reroute for broken boot IRQs"
689 depends on X86_IO_APIC
691 This option enables a workaround that fixes a source of
692 spurious interrupts. This is recommended when threaded
693 interrupt handling is used on systems where the generation of
694 superfluous "boot interrupts" cannot be disabled.
696 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
697 entry in the chipset's IO-APIC is masked (as, e.g. the RT
698 kernel does during interrupt handling). On chipsets where this
699 boot IRQ generation cannot be disabled, this workaround keeps
700 the original IRQ line masked so that only the equivalent "boot
701 IRQ" is delivered to the CPUs. The workaround also tells the
702 kernel to set up the IRQ handler on the boot IRQ line. In this
703 way only one interrupt is delivered to the kernel. Otherwise
704 the spurious second interrupt may cause the kernel to bring
705 down (vital) interrupt lines.
707 Only affects "broken" chipsets. Interrupt sharing may be
708 increased on these systems.
711 bool "Machine Check Exception"
713 Machine Check Exception support allows the processor to notify the
714 kernel if it detects a problem (e.g. overheating, component failure).
715 The action the kernel takes depends on the severity of the problem,
716 ranging from a warning message on the console, to halting the machine.
717 Your processor must be a Pentium or newer to support this - check the
718 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
719 have a design flaw which leads to false MCE events - hence MCE is
720 disabled on all P5 processors, unless explicitly enabled with "mce"
721 as a boot argument. Similarly, if MCE is built in and creates a
722 problem on some new non-standard machine, you can boot with "nomce"
723 to disable it. MCE support simply ignores non-MCE processors like
724 the 386 and 486, so nearly everyone can say Y here.
728 prompt "Intel MCE features"
729 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
731 Additional support for intel specific MCE features such as
736 prompt "AMD MCE features"
737 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
739 Additional support for AMD specific MCE features such as
740 the DRAM Error Threshold.
742 config X86_MCE_NONFATAL
743 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
744 depends on X86_32 && X86_MCE
746 Enabling this feature starts a timer that triggers every 5 seconds which
747 will look at the machine check registers to see if anything happened.
748 Non-fatal problems automatically get corrected (but still logged).
749 Disable this if you don't want to see these messages.
750 Seeing the messages this option prints out may be indicative of dying
751 or out-of-spec (ie, overclocked) hardware.
752 This option only does something on certain CPUs.
753 (AMD Athlon/Duron and Intel Pentium 4)
755 config X86_MCE_P4THERMAL
756 bool "check for P4 thermal throttling interrupt."
757 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
759 Enabling this feature will cause a message to be printed when the P4
760 enters thermal throttling.
763 bool "Enable VM86 support" if EMBEDDED
767 This option is required by programs like DOSEMU to run 16-bit legacy
768 code on X86 processors. It also may be needed by software like
769 XFree86 to initialize some video cards via BIOS. Disabling this
770 option saves about 6k.
773 tristate "Toshiba Laptop support"
776 This adds a driver to safely access the System Management Mode of
777 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
778 not work on models with a Phoenix BIOS. The System Management Mode
779 is used to set the BIOS and power saving options on Toshiba portables.
781 For information on utilities to make use of this driver see the
782 Toshiba Linux utilities web site at:
783 <http://www.buzzard.org.uk/toshiba/>.
785 Say Y if you intend to run this kernel on a Toshiba portable.
789 tristate "Dell laptop support"
791 This adds a driver to safely access the System Management Mode
792 of the CPU on the Dell Inspiron 8000. The System Management Mode
793 is used to read cpu temperature and cooling fan status and to
794 control the fans on the I8K portables.
796 This driver has been tested only on the Inspiron 8000 but it may
797 also work with other Dell laptops. You can force loading on other
798 models by passing the parameter `force=1' to the module. Use at
801 For information on utilities to make use of this driver see the
802 I8K Linux utilities web site at:
803 <http://people.debian.org/~dz/i8k/>
805 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
808 config X86_REBOOTFIXUPS
809 bool "Enable X86 board specific fixups for reboot"
812 This enables chipset and/or board specific fixups to be done
813 in order to get reboot to work correctly. This is only needed on
814 some combinations of hardware and BIOS. The symptom, for which
815 this config is intended, is when reboot ends with a stalled/hung
818 Currently, the only fixup is for the Geode machines using
819 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
821 Say Y if you want to enable the fixup. Currently, it's safe to
822 enable this option even if you don't need it.
826 tristate "/dev/cpu/microcode - microcode support"
829 If you say Y here, you will be able to update the microcode on
830 certain Intel and AMD processors. The Intel support is for the
831 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
832 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
833 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
834 You will obviously need the actual microcode binary data itself
835 which is not shipped with the Linux kernel.
837 This option selects the general module only, you need to select
838 at least one vendor specific module as well.
840 To compile this driver as a module, choose M here: the
841 module will be called microcode.
843 config MICROCODE_INTEL
844 bool "Intel microcode patch loading support"
849 This options enables microcode patch loading support for Intel
852 For latest news and information on obtaining all the required
853 Intel ingredients for this driver, check:
854 <http://www.urbanmyth.org/microcode/>.
857 bool "AMD microcode patch loading support"
861 If you select this option, microcode patch loading support for AMD
862 processors will be enabled.
864 config MICROCODE_OLD_INTERFACE
869 tristate "/dev/cpu/*/msr - Model-specific register support"
871 This device gives privileged processes access to the x86
872 Model-Specific Registers (MSRs). It is a character device with
873 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
874 MSR accesses are directed to a specific CPU on multi-processor
878 tristate "/dev/cpu/*/cpuid - CPU information support"
880 This device gives processes access to the x86 CPUID instruction to
881 be executed on a specific processor. It is a character device
882 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
886 prompt "High Memory Support"
887 default HIGHMEM4G if !X86_NUMAQ
888 default HIGHMEM64G if X86_NUMAQ
893 depends on !X86_NUMAQ
895 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
896 However, the address space of 32-bit x86 processors is only 4
897 Gigabytes large. That means that, if you have a large amount of
898 physical memory, not all of it can be "permanently mapped" by the
899 kernel. The physical memory that's not permanently mapped is called
902 If you are compiling a kernel which will never run on a machine with
903 more than 1 Gigabyte total physical RAM, answer "off" here (default
904 choice and suitable for most users). This will result in a "3GB/1GB"
905 split: 3GB are mapped so that each process sees a 3GB virtual memory
906 space and the remaining part of the 4GB virtual memory space is used
907 by the kernel to permanently map as much physical memory as
910 If the machine has between 1 and 4 Gigabytes physical RAM, then
913 If more than 4 Gigabytes is used then answer "64GB" here. This
914 selection turns Intel PAE (Physical Address Extension) mode on.
915 PAE implements 3-level paging on IA32 processors. PAE is fully
916 supported by Linux, PAE mode is implemented on all recent Intel
917 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
918 then the kernel will not boot on CPUs that don't support PAE!
920 The actual amount of total physical memory will either be
921 auto detected or can be forced by using a kernel command line option
922 such as "mem=256M". (Try "man bootparam" or see the documentation of
923 your boot loader (lilo or loadlin) about how to pass options to the
924 kernel at boot time.)
926 If unsure, say "off".
930 depends on !X86_NUMAQ
932 Select this if you have a 32-bit processor and between 1 and 4
933 gigabytes of physical RAM.
937 depends on !M386 && !M486
940 Select this if you have a 32-bit processor and more than 4
941 gigabytes of physical RAM.
946 depends on EXPERIMENTAL
947 prompt "Memory split" if EMBEDDED
951 Select the desired split between kernel and user memory.
953 If the address range available to the kernel is less than the
954 physical memory installed, the remaining memory will be available
955 as "high memory". Accessing high memory is a little more costly
956 than low memory, as it needs to be mapped into the kernel first.
957 Note that increasing the kernel address space limits the range
958 available to user programs, making the address space there
959 tighter. Selecting anything other than the default 3G/1G split
960 will also likely make your kernel incompatible with binary-only
963 If you are not absolutely sure what you are doing, leave this
967 bool "3G/1G user/kernel split"
968 config VMSPLIT_3G_OPT
970 bool "3G/1G user/kernel split (for full 1G low memory)"
972 bool "2G/2G user/kernel split"
973 config VMSPLIT_2G_OPT
975 bool "2G/2G user/kernel split (for full 2G low memory)"
977 bool "1G/3G user/kernel split"
982 default 0xB0000000 if VMSPLIT_3G_OPT
983 default 0x80000000 if VMSPLIT_2G
984 default 0x78000000 if VMSPLIT_2G_OPT
985 default 0x40000000 if VMSPLIT_1G
991 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
994 bool "PAE (Physical Address Extension) Support"
995 depends on X86_32 && !HIGHMEM4G
997 PAE is required for NX support, and furthermore enables
998 larger swapspace support for non-overcommit purposes. It
999 has the cost of more pagetable lookup overhead, and also
1000 consumes more pagetable space per process.
1002 config ARCH_PHYS_ADDR_T_64BIT
1003 def_bool X86_64 || X86_PAE
1005 config DIRECT_GBPAGES
1006 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1010 Allow the kernel linear mapping to use 1GB pages on CPUs that
1011 support it. This can improve the kernel's performance a tiny bit by
1012 reducing TLB pressure. If in doubt, say "Y".
1014 # Common NUMA Features
1016 bool "Numa Memory Allocation and Scheduler Support"
1018 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1019 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1021 Enable NUMA (Non Uniform Memory Access) support.
1023 The kernel will try to allocate memory used by a CPU on the
1024 local memory controller of the CPU and add some more
1025 NUMA awareness to the kernel.
1027 For 64-bit this is recommended if the system is Intel Core i7
1028 (or later), AMD Opteron, or EM64T NUMA.
1030 For 32-bit this is only needed on (rare) 32-bit-only platforms
1031 that support NUMA topologies, such as NUMAQ / Summit, or if you
1032 boot a 32-bit kernel on a 64-bit NUMA platform.
1034 Otherwise, you should say N.
1036 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1037 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1041 prompt "Old style AMD Opteron NUMA detection"
1042 depends on X86_64 && NUMA && PCI
1044 Enable K8 NUMA node topology detection. You should say Y here if
1045 you have a multi processor AMD K8 system. This uses an old
1046 method to read the NUMA configuration directly from the builtin
1047 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1048 instead, which also takes priority if both are compiled in.
1050 config X86_64_ACPI_NUMA
1052 prompt "ACPI NUMA detection"
1053 depends on X86_64 && NUMA && ACPI && PCI
1056 Enable ACPI SRAT based node topology detection.
1058 # Some NUMA nodes have memory ranges that span
1059 # other nodes. Even though a pfn is valid and
1060 # between a node's start and end pfns, it may not
1061 # reside on that node. See memmap_init_zone()
1063 config NODES_SPAN_OTHER_NODES
1065 depends on X86_64_ACPI_NUMA
1068 bool "NUMA emulation"
1069 depends on X86_64 && NUMA
1071 Enable NUMA emulation. A flat machine will be split
1072 into virtual nodes when booted with "numa=fake=N", where N is the
1073 number of nodes. This is only useful for debugging.
1076 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1078 default "9" if MAXSMP
1079 default "6" if X86_64
1080 default "4" if X86_NUMAQ
1082 depends on NEED_MULTIPLE_NODES
1084 Specify the maximum number of NUMA Nodes available on the target
1085 system. Increases memory reserved to accomodate various tables.
1087 config HAVE_ARCH_BOOTMEM_NODE
1089 depends on X86_32 && NUMA
1091 config ARCH_HAVE_MEMORY_PRESENT
1093 depends on X86_32 && DISCONTIGMEM
1095 config NEED_NODE_MEMMAP_SIZE
1097 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1099 config HAVE_ARCH_ALLOC_REMAP
1101 depends on X86_32 && NUMA
1103 config ARCH_FLATMEM_ENABLE
1105 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1107 config ARCH_DISCONTIGMEM_ENABLE
1109 depends on NUMA && X86_32
1111 config ARCH_DISCONTIGMEM_DEFAULT
1113 depends on NUMA && X86_32
1115 config ARCH_SPARSEMEM_DEFAULT
1119 config ARCH_SPARSEMEM_ENABLE
1121 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1122 select SPARSEMEM_STATIC if X86_32
1123 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1125 config ARCH_SELECT_MEMORY_MODEL
1127 depends on ARCH_SPARSEMEM_ENABLE
1129 config ARCH_MEMORY_PROBE
1131 depends on MEMORY_HOTPLUG
1136 bool "Allocate 3rd-level pagetables from highmem"
1137 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1139 The VM uses one page table entry for each page of physical memory.
1140 For systems with a lot of RAM, this can be wasteful of precious
1141 low memory. Setting this option will put user-space page table
1142 entries in high memory.
1144 config X86_CHECK_BIOS_CORRUPTION
1145 bool "Check for low memory corruption"
1147 Periodically check for memory corruption in low memory, which
1148 is suspected to be caused by BIOS. Even when enabled in the
1149 configuration, it is disabled at runtime. Enable it by
1150 setting "memory_corruption_check=1" on the kernel command
1151 line. By default it scans the low 64k of memory every 60
1152 seconds; see the memory_corruption_check_size and
1153 memory_corruption_check_period parameters in
1154 Documentation/kernel-parameters.txt to adjust this.
1156 When enabled with the default parameters, this option has
1157 almost no overhead, as it reserves a relatively small amount
1158 of memory and scans it infrequently. It both detects corruption
1159 and prevents it from affecting the running system.
1161 It is, however, intended as a diagnostic tool; if repeatable
1162 BIOS-originated corruption always affects the same memory,
1163 you can use memmap= to prevent the kernel from using that
1166 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1167 bool "Set the default setting of memory_corruption_check"
1168 depends on X86_CHECK_BIOS_CORRUPTION
1171 Set whether the default state of memory_corruption_check is
1174 config X86_RESERVE_LOW_64K
1175 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1178 Reserve the first 64K of physical RAM on BIOSes that are known
1179 to potentially corrupt that memory range. A numbers of BIOSes are
1180 known to utilize this area during suspend/resume, so it must not
1181 be used by the kernel.
1183 Set this to N if you are absolutely sure that you trust the BIOS
1184 to get all its memory reservations and usages right.
1186 If you have doubts about the BIOS (e.g. suspend/resume does not
1187 work or there's kernel crashes after certain hardware hotplug
1188 events) and it's not AMI or Phoenix, then you might want to enable
1189 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1190 corruption patterns.
1194 config MATH_EMULATION
1196 prompt "Math emulation" if X86_32
1198 Linux can emulate a math coprocessor (used for floating point
1199 operations) if you don't have one. 486DX and Pentium processors have
1200 a math coprocessor built in, 486SX and 386 do not, unless you added
1201 a 487DX or 387, respectively. (The messages during boot time can
1202 give you some hints here ["man dmesg"].) Everyone needs either a
1203 coprocessor or this emulation.
1205 If you don't have a math coprocessor, you need to say Y here; if you
1206 say Y here even though you have a coprocessor, the coprocessor will
1207 be used nevertheless. (This behavior can be changed with the kernel
1208 command line option "no387", which comes handy if your coprocessor
1209 is broken. Try "man bootparam" or see the documentation of your boot
1210 loader (lilo or loadlin) about how to pass options to the kernel at
1211 boot time.) This means that it is a good idea to say Y here if you
1212 intend to use this kernel on different machines.
1214 More information about the internals of the Linux math coprocessor
1215 emulation can be found in <file:arch/x86/math-emu/README>.
1217 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1218 kernel, it won't hurt.
1221 bool "MTRR (Memory Type Range Register) support"
1223 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1224 the Memory Type Range Registers (MTRRs) may be used to control
1225 processor access to memory ranges. This is most useful if you have
1226 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1227 allows bus write transfers to be combined into a larger transfer
1228 before bursting over the PCI/AGP bus. This can increase performance
1229 of image write operations 2.5 times or more. Saying Y here creates a
1230 /proc/mtrr file which may be used to manipulate your processor's
1231 MTRRs. Typically the X server should use this.
1233 This code has a reasonably generic interface so that similar
1234 control registers on other processors can be easily supported
1237 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1238 Registers (ARRs) which provide a similar functionality to MTRRs. For
1239 these, the ARRs are used to emulate the MTRRs.
1240 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1241 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1242 write-combining. All of these processors are supported by this code
1243 and it makes sense to say Y here if you have one of them.
1245 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1246 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1247 can lead to all sorts of problems, so it's good to say Y here.
1249 You can safely say Y even if your machine doesn't have MTRRs, you'll
1250 just add about 9 KB to your kernel.
1252 See <file:Documentation/x86/mtrr.txt> for more information.
1254 config MTRR_SANITIZER
1256 prompt "MTRR cleanup support"
1259 Convert MTRR layout from continuous to discrete, so X drivers can
1260 add writeback entries.
1262 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1263 The largest mtrr entry size for a continous block can be set with
1268 config MTRR_SANITIZER_ENABLE_DEFAULT
1269 int "MTRR cleanup enable value (0-1)"
1272 depends on MTRR_SANITIZER
1274 Enable mtrr cleanup default value
1276 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1277 int "MTRR cleanup spare reg num (0-7)"
1280 depends on MTRR_SANITIZER
1282 mtrr cleanup spare entries default, it can be changed via
1283 mtrr_spare_reg_nr=N on the kernel command line.
1287 prompt "x86 PAT support"
1290 Use PAT attributes to setup page level cache control.
1292 PATs are the modern equivalents of MTRRs and are much more
1293 flexible than MTRRs.
1295 Say N here if you see bootup problems (boot crash, boot hang,
1296 spontaneous reboots) or a non-working video driver.
1301 bool "EFI runtime service support"
1304 This enables the kernel to use EFI runtime services that are
1305 available (such as the EFI variable services).
1307 This option is only useful on systems that have EFI firmware.
1308 In addition, you should use the latest ELILO loader available
1309 at <http://elilo.sourceforge.net> in order to take advantage
1310 of EFI runtime services. However, even with this option, the
1311 resultant kernel should continue to boot on existing non-EFI
1316 prompt "Enable seccomp to safely compute untrusted bytecode"
1318 This kernel feature is useful for number crunching applications
1319 that may need to compute untrusted bytecode during their
1320 execution. By using pipes or other transports made available to
1321 the process as file descriptors supporting the read/write
1322 syscalls, it's possible to isolate those applications in
1323 their own address space using seccomp. Once seccomp is
1324 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1325 and the task is only allowed to execute a few safe syscalls
1326 defined by each seccomp mode.
1328 If unsure, say Y. Only embedded should say N here.
1330 config CC_STACKPROTECTOR_ALL
1333 config CC_STACKPROTECTOR
1334 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1336 select CC_STACKPROTECTOR_ALL
1338 This option turns on the -fstack-protector GCC feature. This
1339 feature puts, at the beginning of functions, a canary value on
1340 the stack just before the return address, and validates
1341 the value just before actually returning. Stack based buffer
1342 overflows (that need to overwrite this return address) now also
1343 overwrite the canary, which gets detected and the attack is then
1344 neutralized via a kernel panic.
1346 This feature requires gcc version 4.2 or above, or a distribution
1347 gcc with the feature backported. Older versions are automatically
1348 detected and for those versions, this configuration option is
1349 ignored. (and a warning is printed during bootup)
1351 source kernel/Kconfig.hz
1354 bool "kexec system call"
1356 kexec is a system call that implements the ability to shutdown your
1357 current kernel, and to start another kernel. It is like a reboot
1358 but it is independent of the system firmware. And like a reboot
1359 you can start any kernel with it, not just Linux.
1361 The name comes from the similarity to the exec system call.
1363 It is an ongoing process to be certain the hardware in a machine
1364 is properly shutdown, so do not be surprised if this code does not
1365 initially work for you. It may help to enable device hotplugging
1366 support. As of this writing the exact hardware interface is
1367 strongly in flux, so no good recommendation can be made.
1370 bool "kernel crash dumps"
1371 depends on X86_64 || (X86_32 && HIGHMEM)
1373 Generate crash dump after being started by kexec.
1374 This should be normally only set in special crash dump kernels
1375 which are loaded in the main kernel with kexec-tools into
1376 a specially reserved region and then later executed after
1377 a crash by kdump/kexec. The crash dump kernel must be compiled
1378 to a memory address not used by the main kernel or BIOS using
1379 PHYSICAL_START, or it must be built as a relocatable image
1380 (CONFIG_RELOCATABLE=y).
1381 For more details see Documentation/kdump/kdump.txt
1384 bool "kexec jump (EXPERIMENTAL)"
1385 depends on EXPERIMENTAL
1386 depends on KEXEC && HIBERNATION && X86_32
1388 Jump between original kernel and kexeced kernel and invoke
1389 code in physical address mode via KEXEC
1391 config PHYSICAL_START
1392 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1393 default "0x1000000" if X86_NUMAQ
1394 default "0x200000" if X86_64
1397 This gives the physical address where the kernel is loaded.
1399 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1400 bzImage will decompress itself to above physical address and
1401 run from there. Otherwise, bzImage will run from the address where
1402 it has been loaded by the boot loader and will ignore above physical
1405 In normal kdump cases one does not have to set/change this option
1406 as now bzImage can be compiled as a completely relocatable image
1407 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1408 address. This option is mainly useful for the folks who don't want
1409 to use a bzImage for capturing the crash dump and want to use a
1410 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1411 to be specifically compiled to run from a specific memory area
1412 (normally a reserved region) and this option comes handy.
1414 So if you are using bzImage for capturing the crash dump, leave
1415 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1416 Otherwise if you plan to use vmlinux for capturing the crash dump
1417 change this value to start of the reserved region (Typically 16MB
1418 0x1000000). In other words, it can be set based on the "X" value as
1419 specified in the "crashkernel=YM@XM" command line boot parameter
1420 passed to the panic-ed kernel. Typically this parameter is set as
1421 crashkernel=64M@16M. Please take a look at
1422 Documentation/kdump/kdump.txt for more details about crash dumps.
1424 Usage of bzImage for capturing the crash dump is recommended as
1425 one does not have to build two kernels. Same kernel can be used
1426 as production kernel and capture kernel. Above option should have
1427 gone away after relocatable bzImage support is introduced. But it
1428 is present because there are users out there who continue to use
1429 vmlinux for dump capture. This option should go away down the
1432 Don't change this unless you know what you are doing.
1435 bool "Build a relocatable kernel (EXPERIMENTAL)"
1436 depends on EXPERIMENTAL
1438 This builds a kernel image that retains relocation information
1439 so it can be loaded someplace besides the default 1MB.
1440 The relocations tend to make the kernel binary about 10% larger,
1441 but are discarded at runtime.
1443 One use is for the kexec on panic case where the recovery kernel
1444 must live at a different physical address than the primary
1447 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1448 it has been loaded at and the compile time physical address
1449 (CONFIG_PHYSICAL_START) is ignored.
1451 config PHYSICAL_ALIGN
1453 prompt "Alignment value to which kernel should be aligned" if X86_32
1454 default "0x100000" if X86_32
1455 default "0x200000" if X86_64
1456 range 0x2000 0x400000
1458 This value puts the alignment restrictions on physical address
1459 where kernel is loaded and run from. Kernel is compiled for an
1460 address which meets above alignment restriction.
1462 If bootloader loads the kernel at a non-aligned address and
1463 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1464 address aligned to above value and run from there.
1466 If bootloader loads the kernel at a non-aligned address and
1467 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1468 load address and decompress itself to the address it has been
1469 compiled for and run from there. The address for which kernel is
1470 compiled already meets above alignment restrictions. Hence the
1471 end result is that kernel runs from a physical address meeting
1472 above alignment restrictions.
1474 Don't change this unless you know what you are doing.
1477 bool "Support for hot-pluggable CPUs"
1478 depends on SMP && HOTPLUG
1480 Say Y here to allow turning CPUs off and on. CPUs can be
1481 controlled through /sys/devices/system/cpu.
1482 ( Note: power management support will enable this option
1483 automatically on SMP systems. )
1484 Say N if you want to disable CPU hotplug.
1488 prompt "Compat VDSO support"
1489 depends on X86_32 || IA32_EMULATION
1491 Map the 32-bit VDSO to the predictable old-style address too.
1493 Say N here if you are running a sufficiently recent glibc
1494 version (2.3.3 or later), to remove the high-mapped
1495 VDSO mapping and to exclusively use the randomized VDSO.
1500 bool "Built-in kernel command line"
1503 Allow for specifying boot arguments to the kernel at
1504 build time. On some systems (e.g. embedded ones), it is
1505 necessary or convenient to provide some or all of the
1506 kernel boot arguments with the kernel itself (that is,
1507 to not rely on the boot loader to provide them.)
1509 To compile command line arguments into the kernel,
1510 set this option to 'Y', then fill in the
1511 the boot arguments in CONFIG_CMDLINE.
1513 Systems with fully functional boot loaders (i.e. non-embedded)
1514 should leave this option set to 'N'.
1517 string "Built-in kernel command string"
1518 depends on CMDLINE_BOOL
1521 Enter arguments here that should be compiled into the kernel
1522 image and used at boot time. If the boot loader provides a
1523 command line at boot time, it is appended to this string to
1524 form the full kernel command line, when the system boots.
1526 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1527 change this behavior.
1529 In most cases, the command line (whether built-in or provided
1530 by the boot loader) should specify the device for the root
1533 config CMDLINE_OVERRIDE
1534 bool "Built-in command line overrides boot loader arguments"
1536 depends on CMDLINE_BOOL
1538 Set this option to 'Y' to have the kernel ignore the boot loader
1539 command line, and use ONLY the built-in command line.
1541 This is used to work around broken boot loaders. This should
1542 be set to 'N' under normal conditions.
1546 config ARCH_ENABLE_MEMORY_HOTPLUG
1548 depends on X86_64 || (X86_32 && HIGHMEM)
1550 config ARCH_ENABLE_MEMORY_HOTREMOVE
1552 depends on MEMORY_HOTPLUG
1554 config HAVE_ARCH_EARLY_PFN_TO_NID
1558 menu "Power management and ACPI options"
1560 config ARCH_HIBERNATION_HEADER
1562 depends on X86_64 && HIBERNATION
1564 source "kernel/power/Kconfig"
1566 source "drivers/acpi/Kconfig"
1571 depends on APM || APM_MODULE
1574 tristate "APM (Advanced Power Management) BIOS support"
1575 depends on X86_32 && PM_SLEEP
1577 APM is a BIOS specification for saving power using several different
1578 techniques. This is mostly useful for battery powered laptops with
1579 APM compliant BIOSes. If you say Y here, the system time will be
1580 reset after a RESUME operation, the /proc/apm device will provide
1581 battery status information, and user-space programs will receive
1582 notification of APM "events" (e.g. battery status change).
1584 If you select "Y" here, you can disable actual use of the APM
1585 BIOS by passing the "apm=off" option to the kernel at boot time.
1587 Note that the APM support is almost completely disabled for
1588 machines with more than one CPU.
1590 In order to use APM, you will need supporting software. For location
1591 and more information, read <file:Documentation/power/pm.txt> and the
1592 Battery Powered Linux mini-HOWTO, available from
1593 <http://www.tldp.org/docs.html#howto>.
1595 This driver does not spin down disk drives (see the hdparm(8)
1596 manpage ("man 8 hdparm") for that), and it doesn't turn off
1597 VESA-compliant "green" monitors.
1599 This driver does not support the TI 4000M TravelMate and the ACER
1600 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1601 desktop machines also don't have compliant BIOSes, and this driver
1602 may cause those machines to panic during the boot phase.
1604 Generally, if you don't have a battery in your machine, there isn't
1605 much point in using this driver and you should say N. If you get
1606 random kernel OOPSes or reboots that don't seem to be related to
1607 anything, try disabling/enabling this option (or disabling/enabling
1610 Some other things you should try when experiencing seemingly random,
1613 1) make sure that you have enough swap space and that it is
1615 2) pass the "no-hlt" option to the kernel
1616 3) switch on floating point emulation in the kernel and pass
1617 the "no387" option to the kernel
1618 4) pass the "floppy=nodma" option to the kernel
1619 5) pass the "mem=4M" option to the kernel (thereby disabling
1620 all but the first 4 MB of RAM)
1621 6) make sure that the CPU is not over clocked.
1622 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1623 8) disable the cache from your BIOS settings
1624 9) install a fan for the video card or exchange video RAM
1625 10) install a better fan for the CPU
1626 11) exchange RAM chips
1627 12) exchange the motherboard.
1629 To compile this driver as a module, choose M here: the
1630 module will be called apm.
1634 config APM_IGNORE_USER_SUSPEND
1635 bool "Ignore USER SUSPEND"
1637 This option will ignore USER SUSPEND requests. On machines with a
1638 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1639 series notebooks, it is necessary to say Y because of a BIOS bug.
1641 config APM_DO_ENABLE
1642 bool "Enable PM at boot time"
1644 Enable APM features at boot time. From page 36 of the APM BIOS
1645 specification: "When disabled, the APM BIOS does not automatically
1646 power manage devices, enter the Standby State, enter the Suspend
1647 State, or take power saving steps in response to CPU Idle calls."
1648 This driver will make CPU Idle calls when Linux is idle (unless this
1649 feature is turned off -- see "Do CPU IDLE calls", below). This
1650 should always save battery power, but more complicated APM features
1651 will be dependent on your BIOS implementation. You may need to turn
1652 this option off if your computer hangs at boot time when using APM
1653 support, or if it beeps continuously instead of suspending. Turn
1654 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1655 T400CDT. This is off by default since most machines do fine without
1659 bool "Make CPU Idle calls when idle"
1661 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1662 On some machines, this can activate improved power savings, such as
1663 a slowed CPU clock rate, when the machine is idle. These idle calls
1664 are made after the idle loop has run for some length of time (e.g.,
1665 333 mS). On some machines, this will cause a hang at boot time or
1666 whenever the CPU becomes idle. (On machines with more than one CPU,
1667 this option does nothing.)
1669 config APM_DISPLAY_BLANK
1670 bool "Enable console blanking using APM"
1672 Enable console blanking using the APM. Some laptops can use this to
1673 turn off the LCD backlight when the screen blanker of the Linux
1674 virtual console blanks the screen. Note that this is only used by
1675 the virtual console screen blanker, and won't turn off the backlight
1676 when using the X Window system. This also doesn't have anything to
1677 do with your VESA-compliant power-saving monitor. Further, this
1678 option doesn't work for all laptops -- it might not turn off your
1679 backlight at all, or it might print a lot of errors to the console,
1680 especially if you are using gpm.
1682 config APM_ALLOW_INTS
1683 bool "Allow interrupts during APM BIOS calls"
1685 Normally we disable external interrupts while we are making calls to
1686 the APM BIOS as a measure to lessen the effects of a badly behaving
1687 BIOS implementation. The BIOS should reenable interrupts if it
1688 needs to. Unfortunately, some BIOSes do not -- especially those in
1689 many of the newer IBM Thinkpads. If you experience hangs when you
1690 suspend, try setting this to Y. Otherwise, say N.
1694 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1696 source "drivers/cpuidle/Kconfig"
1698 source "drivers/idle/Kconfig"
1703 menu "Bus options (PCI etc.)"
1708 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1710 Find out whether you have a PCI motherboard. PCI is the name of a
1711 bus system, i.e. the way the CPU talks to the other stuff inside
1712 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1713 VESA. If you have PCI, say Y, otherwise N.
1716 prompt "PCI access mode"
1717 depends on X86_32 && PCI
1720 On PCI systems, the BIOS can be used to detect the PCI devices and
1721 determine their configuration. However, some old PCI motherboards
1722 have BIOS bugs and may crash if this is done. Also, some embedded
1723 PCI-based systems don't have any BIOS at all. Linux can also try to
1724 detect the PCI hardware directly without using the BIOS.
1726 With this option, you can specify how Linux should detect the
1727 PCI devices. If you choose "BIOS", the BIOS will be used,
1728 if you choose "Direct", the BIOS won't be used, and if you
1729 choose "MMConfig", then PCI Express MMCONFIG will be used.
1730 If you choose "Any", the kernel will try MMCONFIG, then the
1731 direct access method and falls back to the BIOS if that doesn't
1732 work. If unsure, go with the default, which is "Any".
1737 config PCI_GOMMCONFIG
1754 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1756 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1759 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1763 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1767 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1774 bool "Support mmconfig PCI config space access"
1775 depends on X86_64 && PCI && ACPI
1778 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1779 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1781 DMA remapping (DMAR) devices support enables independent address
1782 translations for Direct Memory Access (DMA) from devices.
1783 These DMA remapping devices are reported via ACPI tables
1784 and include PCI device scope covered by these DMA
1789 prompt "Support for Graphics workaround"
1792 Current Graphics drivers tend to use physical address
1793 for DMA and avoid using DMA APIs. Setting this config
1794 option permits the IOMMU driver to set a unity map for
1795 all the OS-visible memory. Hence the driver can continue
1796 to use physical addresses for DMA.
1798 config DMAR_FLOPPY_WA
1802 Floppy disk drivers are know to bypass DMA API calls
1803 thereby failing to work when IOMMU is enabled. This
1804 workaround will setup a 1:1 mapping for the first
1805 16M to make floppy (an ISA device) work.
1808 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1809 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1811 Supports Interrupt remapping for IO-APIC and MSI devices.
1812 To use x2apic mode in the CPU's which support x2APIC enhancements or
1813 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1815 source "drivers/pci/pcie/Kconfig"
1817 source "drivers/pci/Kconfig"
1819 # x86_64 have no ISA slots, but do have ISA-style DMA.
1828 Find out whether you have ISA slots on your motherboard. ISA is the
1829 name of a bus system, i.e. the way the CPU talks to the other stuff
1830 inside your box. Other bus systems are PCI, EISA, MicroChannel
1831 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1832 newer boards don't support it. If you have ISA, say Y, otherwise N.
1838 The Extended Industry Standard Architecture (EISA) bus was
1839 developed as an open alternative to the IBM MicroChannel bus.
1841 The EISA bus provided some of the features of the IBM MicroChannel
1842 bus while maintaining backward compatibility with cards made for
1843 the older ISA bus. The EISA bus saw limited use between 1988 and
1844 1995 when it was made obsolete by the PCI bus.
1846 Say Y here if you are building a kernel for an EISA-based machine.
1850 source "drivers/eisa/Kconfig"
1855 MicroChannel Architecture is found in some IBM PS/2 machines and
1856 laptops. It is a bus system similar to PCI or ISA. See
1857 <file:Documentation/mca.txt> (and especially the web page given
1858 there) before attempting to build an MCA bus kernel.
1860 source "drivers/mca/Kconfig"
1863 tristate "NatSemi SCx200 support"
1865 This provides basic support for National Semiconductor's
1866 (now AMD's) Geode processors. The driver probes for the
1867 PCI-IDs of several on-chip devices, so its a good dependency
1868 for other scx200_* drivers.
1870 If compiled as a module, the driver is named scx200.
1872 config SCx200HR_TIMER
1873 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1874 depends on SCx200 && GENERIC_TIME
1877 This driver provides a clocksource built upon the on-chip
1878 27MHz high-resolution timer. Its also a workaround for
1879 NSC Geode SC-1100's buggy TSC, which loses time when the
1880 processor goes idle (as is done by the scheduler). The
1881 other workaround is idle=poll boot option.
1883 config GEODE_MFGPT_TIMER
1885 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1886 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1888 This driver provides a clock event source based on the MFGPT
1889 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1890 MFGPTs have a better resolution and max interval than the
1891 generic PIT, and are suitable for use as high-res timers.
1894 bool "One Laptop Per Child support"
1897 Add support for detecting the unique features of the OLPC
1904 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1906 source "drivers/pcmcia/Kconfig"
1908 source "drivers/pci/hotplug/Kconfig"
1913 menu "Executable file formats / Emulations"
1915 source "fs/Kconfig.binfmt"
1917 config IA32_EMULATION
1918 bool "IA32 Emulation"
1920 select COMPAT_BINFMT_ELF
1922 Include code to run 32-bit programs under a 64-bit kernel. You should
1923 likely turn this on, unless you're 100% sure that you don't have any
1924 32-bit programs left.
1927 tristate "IA32 a.out support"
1928 depends on IA32_EMULATION
1930 Support old a.out binaries in the 32bit emulation.
1934 depends on IA32_EMULATION
1936 config COMPAT_FOR_U64_ALIGNMENT
1940 config SYSVIPC_COMPAT
1942 depends on COMPAT && SYSVIPC
1947 config HAVE_ATOMIC_IOMAP
1951 source "net/Kconfig"
1953 source "drivers/Kconfig"
1955 source "drivers/firmware/Kconfig"
1959 source "arch/x86/Kconfig.debug"
1961 source "security/Kconfig"
1963 source "crypto/Kconfig"
1965 source "arch/x86/kvm/Kconfig"
1967 source "lib/Kconfig"
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