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
37 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
38 select HAVE_ARCH_KGDB if !X86_VOYAGER
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
136 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
143 depends on !SMP || !X86_VOYAGER
145 config ARCH_SUSPEND_POSSIBLE
147 depends on !X86_VOYAGER
153 config ARCH_POPULATES_NODE_MAP
160 config ARCH_SUPPORTS_OPTIMIZED_INLINING
163 # Use the generic interrupt handling code in kernel/irq/:
164 config GENERIC_HARDIRQS
168 config GENERIC_IRQ_PROBE
172 config GENERIC_PENDING_IRQ
174 depends on GENERIC_HARDIRQS && SMP
179 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
182 config USE_GENERIC_SMP_HELPERS
188 depends on X86_32 && SMP
192 depends on X86_64 && SMP
197 depends on (X86_32 && !X86_VOYAGER) || X86_64
200 config X86_BIOS_REBOOT
202 depends on !X86_VOYAGER
205 config X86_TRAMPOLINE
207 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
212 source "init/Kconfig"
213 source "kernel/Kconfig.freezer"
215 menu "Processor type and features"
217 source "kernel/time/Kconfig"
220 bool "Symmetric multi-processing support"
222 This enables support for systems with more than one CPU. If you have
223 a system with only one CPU, like most personal computers, say N. If
224 you have a system with more than one CPU, say Y.
226 If you say N here, the kernel will run on single and multiprocessor
227 machines, but will use only one CPU of a multiprocessor machine. If
228 you say Y here, the kernel will run on many, but not all,
229 singleprocessor machines. On a singleprocessor machine, the kernel
230 will run faster if you say N here.
232 Note that if you say Y here and choose architecture "586" or
233 "Pentium" under "Processor family", the kernel will not work on 486
234 architectures. Similarly, multiprocessor kernels for the "PPro"
235 architecture may not work on all Pentium based boards.
237 People using multiprocessor machines who say Y here should also say
238 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
239 Management" code will be disabled if you say Y here.
241 See also <file:Documentation/i386/IO-APIC.txt>,
242 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
243 <http://www.tldp.org/docs.html#howto>.
245 If you don't know what to do here, say N.
247 config X86_HAS_BOOT_CPU_ID
249 depends on X86_VOYAGER
252 bool "Support sparse irq numbering"
253 depends on PCI_MSI || HT_IRQ
255 This enables support for sparse irqs. This is useful for distro
256 kernels that want to define a high CONFIG_NR_CPUS value but still
257 want to have low kernel memory footprint on smaller machines.
259 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
260 out the irq_desc[] array in a more NUMA-friendly way. )
262 If you don't know what to do here, say N.
264 config NUMA_MIGRATE_IRQ_DESC
265 bool "Move irq desc when changing irq smp_affinity"
266 depends on SPARSE_IRQ && NUMA
269 This enables moving irq_desc to cpu/node that irq will use handled.
271 If you don't know what to do here, say N.
273 config X86_FIND_SMP_CONFIG
275 depends on X86_MPPARSE || X86_VOYAGER
278 bool "Enable MPS table" if ACPI
280 depends on X86_LOCAL_APIC
282 For old smp systems that do not have proper acpi support. Newer systems
283 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
286 prompt "Subarchitecture Type"
292 Choose this option if your computer is a standard PC or compatible.
298 Select this for an AMD Elan processor.
300 Do not use this option for K6/Athlon/Opteron processors!
302 If unsure, choose "PC-compatible" instead.
306 depends on X86_32 && (SMP || BROKEN) && !PCI
308 Voyager is an MCA-based 32-way capable SMP architecture proprietary
309 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
313 If you do not specifically know you have a Voyager based machine,
314 say N here, otherwise the kernel you build will not be bootable.
316 config X86_GENERICARCH
317 bool "Generic architecture"
320 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
321 subarchitectures. It is intended for a generic binary kernel.
322 if you select them all, kernel will probe it one by one. and will
328 bool "NUMAQ (IBM/Sequent)"
329 depends on SMP && X86_32 && PCI && X86_MPPARSE
332 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
333 NUMA multiquad box. This changes the way that processors are
334 bootstrapped, and uses Clustered Logical APIC addressing mode instead
335 of Flat Logical. You will need a new lynxer.elf file to flash your
336 firmware with - send email to <Martin.Bligh@us.ibm.com>.
339 bool "Summit/EXA (IBM x440)"
340 depends on X86_32 && SMP
342 This option is needed for IBM systems that use the Summit/EXA chipset.
343 In particular, it is needed for the x440.
346 bool "Support for Unisys ES7000 IA32 series"
347 depends on X86_32 && SMP
349 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
350 supposed to run on an IA32-based Unisys ES7000 system.
353 bool "Support for big SMP systems with more than 8 CPUs"
354 depends on X86_32 && SMP
356 This option is needed for the systems that have more than 8 CPUs
357 and if the system is not of any sub-arch type above.
362 bool "Support for ScaleMP vSMP"
364 depends on X86_64 && PCI
366 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
367 supposed to run on these EM64T-based machines. Only choose this option
368 if you have one of these machines.
373 bool "SGI 320/540 (Visual Workstation)"
374 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
376 The SGI Visual Workstation series is an IA32-based workstation
377 based on SGI systems chips with some legacy PC hardware attached.
379 Say Y here to create a kernel to run on the SGI 320 or 540.
381 A kernel compiled for the Visual Workstation will run on general
382 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
385 bool "RDC R-321x SoC"
388 select X86_REBOOTFIXUPS
390 This option is needed for RDC R-321x system-on-chip, also known
392 If you don't have one of these chips, you should say N here.
395 bool "SGI Ultraviolet"
398 This option is needed in order to support SGI Ultraviolet systems.
399 If you don't have one of these, you should say N here.
401 config SCHED_OMIT_FRAME_POINTER
403 prompt "Single-depth WCHAN output"
406 Calculate simpler /proc/<PID>/wchan values. If this option
407 is disabled then wchan values will recurse back to the
408 caller function. This provides more accurate wchan values,
409 at the expense of slightly more scheduling overhead.
411 If in doubt, say "Y".
413 menuconfig PARAVIRT_GUEST
414 bool "Paravirtualized guest support"
416 Say Y here to get to see options related to running Linux under
417 various hypervisors. This option alone does not add any kernel code.
419 If you say N, all options in this submenu will be skipped and disabled.
423 source "arch/x86/xen/Kconfig"
426 bool "VMI Guest support"
429 depends on !X86_VOYAGER
431 VMI provides a paravirtualized interface to the VMware ESX server
432 (it could be used by other hypervisors in theory too, but is not
433 at the moment), by linking the kernel to a GPL-ed ROM module
434 provided by the hypervisor.
437 bool "KVM paravirtualized clock"
439 select PARAVIRT_CLOCK
440 depends on !X86_VOYAGER
442 Turning on this option will allow you to run a paravirtualized clock
443 when running over the KVM hypervisor. Instead of relying on a PIT
444 (or probably other) emulation by the underlying device model, the host
445 provides the guest with timing infrastructure such as time of day, and
449 bool "KVM Guest support"
451 depends on !X86_VOYAGER
453 This option enables various optimizations for running under the KVM
456 source "arch/x86/lguest/Kconfig"
459 bool "Enable paravirtualization code"
460 depends on !X86_VOYAGER
462 This changes the kernel so it can modify itself when it is run
463 under a hypervisor, potentially improving performance significantly
464 over full virtualization. However, when run without a hypervisor
465 the kernel is theoretically slower and slightly larger.
467 config PARAVIRT_CLOCK
473 config PARAVIRT_DEBUG
474 bool "paravirt-ops debugging"
475 depends on PARAVIRT && DEBUG_KERNEL
477 Enable to debug paravirt_ops internals. Specifically, BUG if
478 a paravirt_op is missing when it is called.
483 This option adds a kernel parameter 'memtest', which allows memtest
485 memtest=0, mean disabled; -- default
486 memtest=1, mean do 1 test pattern;
488 memtest=4, mean do 4 test patterns.
489 If you are unsure how to answer this question, answer N.
491 config X86_SUMMIT_NUMA
493 depends on X86_32 && NUMA && X86_GENERICARCH
495 config X86_CYCLONE_TIMER
497 depends on X86_GENERICARCH
499 source "arch/x86/Kconfig.cpu"
503 prompt "HPET Timer Support" if X86_32
505 Use the IA-PC HPET (High Precision Event Timer) to manage
506 time in preference to the PIT and RTC, if a HPET is
508 HPET is the next generation timer replacing legacy 8254s.
509 The HPET provides a stable time base on SMP
510 systems, unlike the TSC, but it is more expensive to access,
511 as it is off-chip. You can find the HPET spec at
512 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
514 You can safely choose Y here. However, HPET will only be
515 activated if the platform and the BIOS support this feature.
516 Otherwise the 8254 will be used for timing services.
518 Choose N to continue using the legacy 8254 timer.
520 config HPET_EMULATE_RTC
522 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
524 # Mark as embedded because too many people got it wrong.
525 # The code disables itself when not needed.
528 bool "Enable DMI scanning" if EMBEDDED
530 Enabled scanning of DMI to identify machine quirks. Say Y
531 here unless you have verified that your setup is not
532 affected by entries in the DMI blacklist. Required by PNP
536 bool "GART IOMMU support" if EMBEDDED
540 depends on X86_64 && PCI
542 Support for full DMA access of devices with 32bit memory access only
543 on systems with more than 3GB. This is usually needed for USB,
544 sound, many IDE/SATA chipsets and some other devices.
545 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
546 based hardware IOMMU and a software bounce buffer based IOMMU used
547 on Intel systems and as fallback.
548 The code is only active when needed (enough memory and limited
549 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
553 bool "IBM Calgary IOMMU support"
555 depends on X86_64 && PCI && EXPERIMENTAL
557 Support for hardware IOMMUs in IBM's xSeries x366 and x460
558 systems. Needed to run systems with more than 3GB of memory
559 properly with 32-bit PCI devices that do not support DAC
560 (Double Address Cycle). Calgary also supports bus level
561 isolation, where all DMAs pass through the IOMMU. This
562 prevents them from going anywhere except their intended
563 destination. This catches hard-to-find kernel bugs and
564 mis-behaving drivers and devices that do not use the DMA-API
565 properly to set up their DMA buffers. The IOMMU can be
566 turned off at boot time with the iommu=off parameter.
567 Normally the kernel will make the right choice by itself.
570 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
572 prompt "Should Calgary be enabled by default?"
573 depends on CALGARY_IOMMU
575 Should Calgary be enabled by default? if you choose 'y', Calgary
576 will be used (if it exists). If you choose 'n', Calgary will not be
577 used even if it exists. If you choose 'n' and would like to use
578 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
582 bool "AMD IOMMU support"
585 depends on X86_64 && PCI && ACPI
587 With this option you can enable support for AMD IOMMU hardware in
588 your system. An IOMMU is a hardware component which provides
589 remapping of DMA memory accesses from devices. With an AMD IOMMU you
590 can isolate the the DMA memory of different devices and protect the
591 system from misbehaving device drivers or hardware.
593 You can find out if your system has an AMD IOMMU if you look into
594 your BIOS for an option to enable it or if you have an IVRS ACPI
597 config AMD_IOMMU_STATS
598 bool "Export AMD IOMMU statistics to debugfs"
602 This option enables code in the AMD IOMMU driver to collect various
603 statistics about whats happening in the driver and exports that
604 information to userspace via debugfs.
607 # need this always selected by IOMMU for the VIA workaround
611 Support for software bounce buffers used on x86-64 systems
612 which don't have a hardware IOMMU (e.g. the current generation
613 of Intel's x86-64 CPUs). Using this PCI devices which can only
614 access 32-bits of memory can be used on systems with more than
615 3 GB of memory. If unsure, say Y.
618 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
621 def_bool (AMD_IOMMU || DMAR)
624 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
625 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
626 select CPUMASK_OFFSTACK
629 Configure maximum number of CPUS and NUMA Nodes for this architecture.
633 int "Maximum number of CPUs" if SMP && !MAXSMP
634 range 2 512 if SMP && !MAXSMP
636 default "4096" if MAXSMP
637 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
640 This allows you to specify the maximum number of CPUs which this
641 kernel will support. The maximum supported value is 512 and the
642 minimum value which makes sense is 2.
644 This is purely to save memory - each supported CPU adds
645 approximately eight kilobytes to the kernel image.
648 bool "SMT (Hyperthreading) scheduler support"
651 SMT scheduler support improves the CPU scheduler's decision making
652 when dealing with Intel Pentium 4 chips with HyperThreading at a
653 cost of slightly increased overhead in some places. If unsure say
658 prompt "Multi-core scheduler support"
661 Multi-core scheduler support improves the CPU scheduler's decision
662 making when dealing with multi-core CPU chips at a cost of slightly
663 increased overhead in some places. If unsure say N here.
665 source "kernel/Kconfig.preempt"
668 bool "Local APIC support on uniprocessors"
669 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
671 A local APIC (Advanced Programmable Interrupt Controller) is an
672 integrated interrupt controller in the CPU. If you have a single-CPU
673 system which has a processor with a local APIC, you can say Y here to
674 enable and use it. If you say Y here even though your machine doesn't
675 have a local APIC, then the kernel will still run with no slowdown at
676 all. The local APIC supports CPU-generated self-interrupts (timer,
677 performance counters), and the NMI watchdog which detects hard
681 bool "IO-APIC support on uniprocessors"
682 depends on X86_UP_APIC
684 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
685 SMP-capable replacement for PC-style interrupt controllers. Most
686 SMP systems and many recent uniprocessor systems have one.
688 If you have a single-CPU system with an IO-APIC, you can say Y here
689 to use it. If you say Y here even though your machine doesn't have
690 an IO-APIC, then the kernel will still run with no slowdown at all.
692 config X86_LOCAL_APIC
694 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
698 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
700 config X86_VISWS_APIC
702 depends on X86_32 && X86_VISWS
704 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
705 bool "Reroute for broken boot IRQs"
707 depends on X86_IO_APIC
709 This option enables a workaround that fixes a source of
710 spurious interrupts. This is recommended when threaded
711 interrupt handling is used on systems where the generation of
712 superfluous "boot interrupts" cannot be disabled.
714 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
715 entry in the chipset's IO-APIC is masked (as, e.g. the RT
716 kernel does during interrupt handling). On chipsets where this
717 boot IRQ generation cannot be disabled, this workaround keeps
718 the original IRQ line masked so that only the equivalent "boot
719 IRQ" is delivered to the CPUs. The workaround also tells the
720 kernel to set up the IRQ handler on the boot IRQ line. In this
721 way only one interrupt is delivered to the kernel. Otherwise
722 the spurious second interrupt may cause the kernel to bring
723 down (vital) interrupt lines.
725 Only affects "broken" chipsets. Interrupt sharing may be
726 increased on these systems.
729 bool "Machine Check Exception"
730 depends on !X86_VOYAGER
732 Machine Check Exception support allows the processor to notify the
733 kernel if it detects a problem (e.g. overheating, component failure).
734 The action the kernel takes depends on the severity of the problem,
735 ranging from a warning message on the console, to halting the machine.
736 Your processor must be a Pentium or newer to support this - check the
737 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
738 have a design flaw which leads to false MCE events - hence MCE is
739 disabled on all P5 processors, unless explicitly enabled with "mce"
740 as a boot argument. Similarly, if MCE is built in and creates a
741 problem on some new non-standard machine, you can boot with "nomce"
742 to disable it. MCE support simply ignores non-MCE processors like
743 the 386 and 486, so nearly everyone can say Y here.
747 prompt "Intel MCE features"
748 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
750 Additional support for intel specific MCE features such as
755 prompt "AMD MCE features"
756 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
758 Additional support for AMD specific MCE features such as
759 the DRAM Error Threshold.
761 config X86_MCE_NONFATAL
762 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
763 depends on X86_32 && X86_MCE
765 Enabling this feature starts a timer that triggers every 5 seconds which
766 will look at the machine check registers to see if anything happened.
767 Non-fatal problems automatically get corrected (but still logged).
768 Disable this if you don't want to see these messages.
769 Seeing the messages this option prints out may be indicative of dying
770 or out-of-spec (ie, overclocked) hardware.
771 This option only does something on certain CPUs.
772 (AMD Athlon/Duron and Intel Pentium 4)
774 config X86_MCE_P4THERMAL
775 bool "check for P4 thermal throttling interrupt."
776 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
778 Enabling this feature will cause a message to be printed when the P4
779 enters thermal throttling.
782 bool "Enable VM86 support" if EMBEDDED
786 This option is required by programs like DOSEMU to run 16-bit legacy
787 code on X86 processors. It also may be needed by software like
788 XFree86 to initialize some video cards via BIOS. Disabling this
789 option saves about 6k.
792 tristate "Toshiba Laptop support"
795 This adds a driver to safely access the System Management Mode of
796 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
797 not work on models with a Phoenix BIOS. The System Management Mode
798 is used to set the BIOS and power saving options on Toshiba portables.
800 For information on utilities to make use of this driver see the
801 Toshiba Linux utilities web site at:
802 <http://www.buzzard.org.uk/toshiba/>.
804 Say Y if you intend to run this kernel on a Toshiba portable.
808 tristate "Dell laptop support"
810 This adds a driver to safely access the System Management Mode
811 of the CPU on the Dell Inspiron 8000. The System Management Mode
812 is used to read cpu temperature and cooling fan status and to
813 control the fans on the I8K portables.
815 This driver has been tested only on the Inspiron 8000 but it may
816 also work with other Dell laptops. You can force loading on other
817 models by passing the parameter `force=1' to the module. Use at
820 For information on utilities to make use of this driver see the
821 I8K Linux utilities web site at:
822 <http://people.debian.org/~dz/i8k/>
824 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
827 config X86_REBOOTFIXUPS
828 bool "Enable X86 board specific fixups for reboot"
831 This enables chipset and/or board specific fixups to be done
832 in order to get reboot to work correctly. This is only needed on
833 some combinations of hardware and BIOS. The symptom, for which
834 this config is intended, is when reboot ends with a stalled/hung
837 Currently, the only fixup is for the Geode machines using
838 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
840 Say Y if you want to enable the fixup. Currently, it's safe to
841 enable this option even if you don't need it.
845 tristate "/dev/cpu/microcode - microcode support"
848 If you say Y here, you will be able to update the microcode on
849 certain Intel and AMD processors. The Intel support is for the
850 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
851 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
852 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
853 You will obviously need the actual microcode binary data itself
854 which is not shipped with the Linux kernel.
856 This option selects the general module only, you need to select
857 at least one vendor specific module as well.
859 To compile this driver as a module, choose M here: the
860 module will be called microcode.
862 config MICROCODE_INTEL
863 bool "Intel microcode patch loading support"
868 This options enables microcode patch loading support for Intel
871 For latest news and information on obtaining all the required
872 Intel ingredients for this driver, check:
873 <http://www.urbanmyth.org/microcode/>.
876 bool "AMD microcode patch loading support"
880 If you select this option, microcode patch loading support for AMD
881 processors will be enabled.
883 config MICROCODE_OLD_INTERFACE
888 tristate "/dev/cpu/*/msr - Model-specific register support"
890 This device gives privileged processes access to the x86
891 Model-Specific Registers (MSRs). It is a character device with
892 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
893 MSR accesses are directed to a specific CPU on multi-processor
897 tristate "/dev/cpu/*/cpuid - CPU information support"
899 This device gives processes access to the x86 CPUID instruction to
900 be executed on a specific processor. It is a character device
901 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
905 prompt "High Memory Support"
906 default HIGHMEM4G if !X86_NUMAQ
907 default HIGHMEM64G if X86_NUMAQ
912 depends on !X86_NUMAQ
914 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
915 However, the address space of 32-bit x86 processors is only 4
916 Gigabytes large. That means that, if you have a large amount of
917 physical memory, not all of it can be "permanently mapped" by the
918 kernel. The physical memory that's not permanently mapped is called
921 If you are compiling a kernel which will never run on a machine with
922 more than 1 Gigabyte total physical RAM, answer "off" here (default
923 choice and suitable for most users). This will result in a "3GB/1GB"
924 split: 3GB are mapped so that each process sees a 3GB virtual memory
925 space and the remaining part of the 4GB virtual memory space is used
926 by the kernel to permanently map as much physical memory as
929 If the machine has between 1 and 4 Gigabytes physical RAM, then
932 If more than 4 Gigabytes is used then answer "64GB" here. This
933 selection turns Intel PAE (Physical Address Extension) mode on.
934 PAE implements 3-level paging on IA32 processors. PAE is fully
935 supported by Linux, PAE mode is implemented on all recent Intel
936 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
937 then the kernel will not boot on CPUs that don't support PAE!
939 The actual amount of total physical memory will either be
940 auto detected or can be forced by using a kernel command line option
941 such as "mem=256M". (Try "man bootparam" or see the documentation of
942 your boot loader (lilo or loadlin) about how to pass options to the
943 kernel at boot time.)
945 If unsure, say "off".
949 depends on !X86_NUMAQ
951 Select this if you have a 32-bit processor and between 1 and 4
952 gigabytes of physical RAM.
956 depends on !M386 && !M486
959 Select this if you have a 32-bit processor and more than 4
960 gigabytes of physical RAM.
965 depends on EXPERIMENTAL
966 prompt "Memory split" if EMBEDDED
970 Select the desired split between kernel and user memory.
972 If the address range available to the kernel is less than the
973 physical memory installed, the remaining memory will be available
974 as "high memory". Accessing high memory is a little more costly
975 than low memory, as it needs to be mapped into the kernel first.
976 Note that increasing the kernel address space limits the range
977 available to user programs, making the address space there
978 tighter. Selecting anything other than the default 3G/1G split
979 will also likely make your kernel incompatible with binary-only
982 If you are not absolutely sure what you are doing, leave this
986 bool "3G/1G user/kernel split"
987 config VMSPLIT_3G_OPT
989 bool "3G/1G user/kernel split (for full 1G low memory)"
991 bool "2G/2G user/kernel split"
992 config VMSPLIT_2G_OPT
994 bool "2G/2G user/kernel split (for full 2G low memory)"
996 bool "1G/3G user/kernel split"
1001 default 0xB0000000 if VMSPLIT_3G_OPT
1002 default 0x80000000 if VMSPLIT_2G
1003 default 0x78000000 if VMSPLIT_2G_OPT
1004 default 0x40000000 if VMSPLIT_1G
1010 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1013 bool "PAE (Physical Address Extension) Support"
1014 depends on X86_32 && !HIGHMEM4G
1016 PAE is required for NX support, and furthermore enables
1017 larger swapspace support for non-overcommit purposes. It
1018 has the cost of more pagetable lookup overhead, and also
1019 consumes more pagetable space per process.
1021 config ARCH_PHYS_ADDR_T_64BIT
1022 def_bool X86_64 || X86_PAE
1024 config DIRECT_GBPAGES
1025 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1029 Allow the kernel linear mapping to use 1GB pages on CPUs that
1030 support it. This can improve the kernel's performance a tiny bit by
1031 reducing TLB pressure. If in doubt, say "Y".
1033 # Common NUMA Features
1035 bool "Numa Memory Allocation and Scheduler Support"
1037 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1039 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1041 Enable NUMA (Non Uniform Memory Access) support.
1043 The kernel will try to allocate memory used by a CPU on the
1044 local memory controller of the CPU and add some more
1045 NUMA awareness to the kernel.
1047 For 64-bit this is recommended if the system is Intel Core i7
1048 (or later), AMD Opteron, or EM64T NUMA.
1050 For 32-bit this is only needed on (rare) 32-bit-only platforms
1051 that support NUMA topologies, such as NUMAQ / Summit, or if you
1052 boot a 32-bit kernel on a 64-bit NUMA platform.
1054 Otherwise, you should say N.
1056 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1057 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1061 prompt "Old style AMD Opteron NUMA detection"
1062 depends on X86_64 && NUMA && PCI
1064 Enable K8 NUMA node topology detection. You should say Y here if
1065 you have a multi processor AMD K8 system. This uses an old
1066 method to read the NUMA configuration directly from the builtin
1067 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1068 instead, which also takes priority if both are compiled in.
1070 config X86_64_ACPI_NUMA
1072 prompt "ACPI NUMA detection"
1073 depends on X86_64 && NUMA && ACPI && PCI
1076 Enable ACPI SRAT based node topology detection.
1078 # Some NUMA nodes have memory ranges that span
1079 # other nodes. Even though a pfn is valid and
1080 # between a node's start and end pfns, it may not
1081 # reside on that node. See memmap_init_zone()
1083 config NODES_SPAN_OTHER_NODES
1085 depends on X86_64_ACPI_NUMA
1088 bool "NUMA emulation"
1089 depends on X86_64 && NUMA
1091 Enable NUMA emulation. A flat machine will be split
1092 into virtual nodes when booted with "numa=fake=N", where N is the
1093 number of nodes. This is only useful for debugging.
1096 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1098 default "9" if MAXSMP
1099 default "6" if X86_64
1100 default "4" if X86_NUMAQ
1102 depends on NEED_MULTIPLE_NODES
1104 Specify the maximum number of NUMA Nodes available on the target
1105 system. Increases memory reserved to accomodate various tables.
1107 config HAVE_ARCH_BOOTMEM_NODE
1109 depends on X86_32 && NUMA
1111 config ARCH_HAVE_MEMORY_PRESENT
1113 depends on X86_32 && DISCONTIGMEM
1115 config NEED_NODE_MEMMAP_SIZE
1117 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1119 config HAVE_ARCH_ALLOC_REMAP
1121 depends on X86_32 && NUMA
1123 config ARCH_FLATMEM_ENABLE
1125 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1127 config ARCH_DISCONTIGMEM_ENABLE
1129 depends on NUMA && X86_32
1131 config ARCH_DISCONTIGMEM_DEFAULT
1133 depends on NUMA && X86_32
1135 config ARCH_SPARSEMEM_DEFAULT
1139 config ARCH_SPARSEMEM_ENABLE
1141 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1142 select SPARSEMEM_STATIC if X86_32
1143 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1145 config ARCH_SELECT_MEMORY_MODEL
1147 depends on ARCH_SPARSEMEM_ENABLE
1149 config ARCH_MEMORY_PROBE
1151 depends on MEMORY_HOTPLUG
1156 bool "Allocate 3rd-level pagetables from highmem"
1157 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1159 The VM uses one page table entry for each page of physical memory.
1160 For systems with a lot of RAM, this can be wasteful of precious
1161 low memory. Setting this option will put user-space page table
1162 entries in high memory.
1164 config X86_CHECK_BIOS_CORRUPTION
1165 bool "Check for low memory corruption"
1167 Periodically check for memory corruption in low memory, which
1168 is suspected to be caused by BIOS. Even when enabled in the
1169 configuration, it is disabled at runtime. Enable it by
1170 setting "memory_corruption_check=1" on the kernel command
1171 line. By default it scans the low 64k of memory every 60
1172 seconds; see the memory_corruption_check_size and
1173 memory_corruption_check_period parameters in
1174 Documentation/kernel-parameters.txt to adjust this.
1176 When enabled with the default parameters, this option has
1177 almost no overhead, as it reserves a relatively small amount
1178 of memory and scans it infrequently. It both detects corruption
1179 and prevents it from affecting the running system.
1181 It is, however, intended as a diagnostic tool; if repeatable
1182 BIOS-originated corruption always affects the same memory,
1183 you can use memmap= to prevent the kernel from using that
1186 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1187 bool "Set the default setting of memory_corruption_check"
1188 depends on X86_CHECK_BIOS_CORRUPTION
1191 Set whether the default state of memory_corruption_check is
1194 config X86_RESERVE_LOW_64K
1195 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1198 Reserve the first 64K of physical RAM on BIOSes that are known
1199 to potentially corrupt that memory range. A numbers of BIOSes are
1200 known to utilize this area during suspend/resume, so it must not
1201 be used by the kernel.
1203 Set this to N if you are absolutely sure that you trust the BIOS
1204 to get all its memory reservations and usages right.
1206 If you have doubts about the BIOS (e.g. suspend/resume does not
1207 work or there's kernel crashes after certain hardware hotplug
1208 events) and it's not AMI or Phoenix, then you might want to enable
1209 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1210 corruption patterns.
1214 config MATH_EMULATION
1216 prompt "Math emulation" if X86_32
1218 Linux can emulate a math coprocessor (used for floating point
1219 operations) if you don't have one. 486DX and Pentium processors have
1220 a math coprocessor built in, 486SX and 386 do not, unless you added
1221 a 487DX or 387, respectively. (The messages during boot time can
1222 give you some hints here ["man dmesg"].) Everyone needs either a
1223 coprocessor or this emulation.
1225 If you don't have a math coprocessor, you need to say Y here; if you
1226 say Y here even though you have a coprocessor, the coprocessor will
1227 be used nevertheless. (This behavior can be changed with the kernel
1228 command line option "no387", which comes handy if your coprocessor
1229 is broken. Try "man bootparam" or see the documentation of your boot
1230 loader (lilo or loadlin) about how to pass options to the kernel at
1231 boot time.) This means that it is a good idea to say Y here if you
1232 intend to use this kernel on different machines.
1234 More information about the internals of the Linux math coprocessor
1235 emulation can be found in <file:arch/x86/math-emu/README>.
1237 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1238 kernel, it won't hurt.
1241 bool "MTRR (Memory Type Range Register) support"
1243 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1244 the Memory Type Range Registers (MTRRs) may be used to control
1245 processor access to memory ranges. This is most useful if you have
1246 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1247 allows bus write transfers to be combined into a larger transfer
1248 before bursting over the PCI/AGP bus. This can increase performance
1249 of image write operations 2.5 times or more. Saying Y here creates a
1250 /proc/mtrr file which may be used to manipulate your processor's
1251 MTRRs. Typically the X server should use this.
1253 This code has a reasonably generic interface so that similar
1254 control registers on other processors can be easily supported
1257 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1258 Registers (ARRs) which provide a similar functionality to MTRRs. For
1259 these, the ARRs are used to emulate the MTRRs.
1260 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1261 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1262 write-combining. All of these processors are supported by this code
1263 and it makes sense to say Y here if you have one of them.
1265 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1266 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1267 can lead to all sorts of problems, so it's good to say Y here.
1269 You can safely say Y even if your machine doesn't have MTRRs, you'll
1270 just add about 9 KB to your kernel.
1272 See <file:Documentation/x86/mtrr.txt> for more information.
1274 config MTRR_SANITIZER
1276 prompt "MTRR cleanup support"
1279 Convert MTRR layout from continuous to discrete, so X drivers can
1280 add writeback entries.
1282 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1283 The largest mtrr entry size for a continous block can be set with
1288 config MTRR_SANITIZER_ENABLE_DEFAULT
1289 int "MTRR cleanup enable value (0-1)"
1292 depends on MTRR_SANITIZER
1294 Enable mtrr cleanup default value
1296 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1297 int "MTRR cleanup spare reg num (0-7)"
1300 depends on MTRR_SANITIZER
1302 mtrr cleanup spare entries default, it can be changed via
1303 mtrr_spare_reg_nr=N on the kernel command line.
1307 prompt "x86 PAT support"
1310 Use PAT attributes to setup page level cache control.
1312 PATs are the modern equivalents of MTRRs and are much more
1313 flexible than MTRRs.
1315 Say N here if you see bootup problems (boot crash, boot hang,
1316 spontaneous reboots) or a non-working video driver.
1321 bool "EFI runtime service support"
1324 This enables the kernel to use EFI runtime services that are
1325 available (such as the EFI variable services).
1327 This option is only useful on systems that have EFI firmware.
1328 In addition, you should use the latest ELILO loader available
1329 at <http://elilo.sourceforge.net> in order to take advantage
1330 of EFI runtime services. However, even with this option, the
1331 resultant kernel should continue to boot on existing non-EFI
1336 prompt "Enable seccomp to safely compute untrusted bytecode"
1338 This kernel feature is useful for number crunching applications
1339 that may need to compute untrusted bytecode during their
1340 execution. By using pipes or other transports made available to
1341 the process as file descriptors supporting the read/write
1342 syscalls, it's possible to isolate those applications in
1343 their own address space using seccomp. Once seccomp is
1344 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1345 and the task is only allowed to execute a few safe syscalls
1346 defined by each seccomp mode.
1348 If unsure, say Y. Only embedded should say N here.
1350 config CC_STACKPROTECTOR_ALL
1353 config CC_STACKPROTECTOR
1354 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1356 select CC_STACKPROTECTOR_ALL
1358 This option turns on the -fstack-protector GCC feature. This
1359 feature puts, at the beginning of functions, a canary value on
1360 the stack just before the return address, and validates
1361 the value just before actually returning. Stack based buffer
1362 overflows (that need to overwrite this return address) now also
1363 overwrite the canary, which gets detected and the attack is then
1364 neutralized via a kernel panic.
1366 This feature requires gcc version 4.2 or above, or a distribution
1367 gcc with the feature backported. Older versions are automatically
1368 detected and for those versions, this configuration option is
1369 ignored. (and a warning is printed during bootup)
1371 source kernel/Kconfig.hz
1374 bool "kexec system call"
1375 depends on X86_BIOS_REBOOT
1377 kexec is a system call that implements the ability to shutdown your
1378 current kernel, and to start another kernel. It is like a reboot
1379 but it is independent of the system firmware. And like a reboot
1380 you can start any kernel with it, not just Linux.
1382 The name comes from the similarity to the exec system call.
1384 It is an ongoing process to be certain the hardware in a machine
1385 is properly shutdown, so do not be surprised if this code does not
1386 initially work for you. It may help to enable device hotplugging
1387 support. As of this writing the exact hardware interface is
1388 strongly in flux, so no good recommendation can be made.
1391 bool "kernel crash dumps"
1392 depends on X86_64 || (X86_32 && HIGHMEM)
1394 Generate crash dump after being started by kexec.
1395 This should be normally only set in special crash dump kernels
1396 which are loaded in the main kernel with kexec-tools into
1397 a specially reserved region and then later executed after
1398 a crash by kdump/kexec. The crash dump kernel must be compiled
1399 to a memory address not used by the main kernel or BIOS using
1400 PHYSICAL_START, or it must be built as a relocatable image
1401 (CONFIG_RELOCATABLE=y).
1402 For more details see Documentation/kdump/kdump.txt
1405 bool "kexec jump (EXPERIMENTAL)"
1406 depends on EXPERIMENTAL
1407 depends on KEXEC && HIBERNATION && X86_32
1409 Jump between original kernel and kexeced kernel and invoke
1410 code in physical address mode via KEXEC
1412 config PHYSICAL_START
1413 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1414 default "0x1000000" if X86_NUMAQ
1415 default "0x200000" if X86_64
1418 This gives the physical address where the kernel is loaded.
1420 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1421 bzImage will decompress itself to above physical address and
1422 run from there. Otherwise, bzImage will run from the address where
1423 it has been loaded by the boot loader and will ignore above physical
1426 In normal kdump cases one does not have to set/change this option
1427 as now bzImage can be compiled as a completely relocatable image
1428 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1429 address. This option is mainly useful for the folks who don't want
1430 to use a bzImage for capturing the crash dump and want to use a
1431 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1432 to be specifically compiled to run from a specific memory area
1433 (normally a reserved region) and this option comes handy.
1435 So if you are using bzImage for capturing the crash dump, leave
1436 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1437 Otherwise if you plan to use vmlinux for capturing the crash dump
1438 change this value to start of the reserved region (Typically 16MB
1439 0x1000000). In other words, it can be set based on the "X" value as
1440 specified in the "crashkernel=YM@XM" command line boot parameter
1441 passed to the panic-ed kernel. Typically this parameter is set as
1442 crashkernel=64M@16M. Please take a look at
1443 Documentation/kdump/kdump.txt for more details about crash dumps.
1445 Usage of bzImage for capturing the crash dump is recommended as
1446 one does not have to build two kernels. Same kernel can be used
1447 as production kernel and capture kernel. Above option should have
1448 gone away after relocatable bzImage support is introduced. But it
1449 is present because there are users out there who continue to use
1450 vmlinux for dump capture. This option should go away down the
1453 Don't change this unless you know what you are doing.
1456 bool "Build a relocatable kernel (EXPERIMENTAL)"
1457 depends on EXPERIMENTAL
1459 This builds a kernel image that retains relocation information
1460 so it can be loaded someplace besides the default 1MB.
1461 The relocations tend to make the kernel binary about 10% larger,
1462 but are discarded at runtime.
1464 One use is for the kexec on panic case where the recovery kernel
1465 must live at a different physical address than the primary
1468 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1469 it has been loaded at and the compile time physical address
1470 (CONFIG_PHYSICAL_START) is ignored.
1472 config PHYSICAL_ALIGN
1474 prompt "Alignment value to which kernel should be aligned" if X86_32
1475 default "0x100000" if X86_32
1476 default "0x200000" if X86_64
1477 range 0x2000 0x400000
1479 This value puts the alignment restrictions on physical address
1480 where kernel is loaded and run from. Kernel is compiled for an
1481 address which meets above alignment restriction.
1483 If bootloader loads the kernel at a non-aligned address and
1484 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1485 address aligned to above value and run from there.
1487 If bootloader loads the kernel at a non-aligned address and
1488 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1489 load address and decompress itself to the address it has been
1490 compiled for and run from there. The address for which kernel is
1491 compiled already meets above alignment restrictions. Hence the
1492 end result is that kernel runs from a physical address meeting
1493 above alignment restrictions.
1495 Don't change this unless you know what you are doing.
1498 bool "Support for hot-pluggable CPUs"
1499 depends on SMP && HOTPLUG && !X86_VOYAGER
1501 Say Y here to allow turning CPUs off and on. CPUs can be
1502 controlled through /sys/devices/system/cpu.
1503 ( Note: power management support will enable this option
1504 automatically on SMP systems. )
1505 Say N if you want to disable CPU hotplug.
1509 prompt "Compat VDSO support"
1510 depends on X86_32 || IA32_EMULATION
1512 Map the 32-bit VDSO to the predictable old-style address too.
1514 Say N here if you are running a sufficiently recent glibc
1515 version (2.3.3 or later), to remove the high-mapped
1516 VDSO mapping and to exclusively use the randomized VDSO.
1521 bool "Built-in kernel command line"
1524 Allow for specifying boot arguments to the kernel at
1525 build time. On some systems (e.g. embedded ones), it is
1526 necessary or convenient to provide some or all of the
1527 kernel boot arguments with the kernel itself (that is,
1528 to not rely on the boot loader to provide them.)
1530 To compile command line arguments into the kernel,
1531 set this option to 'Y', then fill in the
1532 the boot arguments in CONFIG_CMDLINE.
1534 Systems with fully functional boot loaders (i.e. non-embedded)
1535 should leave this option set to 'N'.
1538 string "Built-in kernel command string"
1539 depends on CMDLINE_BOOL
1542 Enter arguments here that should be compiled into the kernel
1543 image and used at boot time. If the boot loader provides a
1544 command line at boot time, it is appended to this string to
1545 form the full kernel command line, when the system boots.
1547 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1548 change this behavior.
1550 In most cases, the command line (whether built-in or provided
1551 by the boot loader) should specify the device for the root
1554 config CMDLINE_OVERRIDE
1555 bool "Built-in command line overrides boot loader arguments"
1557 depends on CMDLINE_BOOL
1559 Set this option to 'Y' to have the kernel ignore the boot loader
1560 command line, and use ONLY the built-in command line.
1562 This is used to work around broken boot loaders. This should
1563 be set to 'N' under normal conditions.
1567 config ARCH_ENABLE_MEMORY_HOTPLUG
1569 depends on X86_64 || (X86_32 && HIGHMEM)
1571 config ARCH_ENABLE_MEMORY_HOTREMOVE
1573 depends on MEMORY_HOTPLUG
1575 config HAVE_ARCH_EARLY_PFN_TO_NID
1579 menu "Power management and ACPI options"
1580 depends on !X86_VOYAGER
1582 config ARCH_HIBERNATION_HEADER
1584 depends on X86_64 && HIBERNATION
1586 source "kernel/power/Kconfig"
1588 source "drivers/acpi/Kconfig"
1593 depends on APM || APM_MODULE
1596 tristate "APM (Advanced Power Management) BIOS support"
1597 depends on X86_32 && PM_SLEEP
1599 APM is a BIOS specification for saving power using several different
1600 techniques. This is mostly useful for battery powered laptops with
1601 APM compliant BIOSes. If you say Y here, the system time will be
1602 reset after a RESUME operation, the /proc/apm device will provide
1603 battery status information, and user-space programs will receive
1604 notification of APM "events" (e.g. battery status change).
1606 If you select "Y" here, you can disable actual use of the APM
1607 BIOS by passing the "apm=off" option to the kernel at boot time.
1609 Note that the APM support is almost completely disabled for
1610 machines with more than one CPU.
1612 In order to use APM, you will need supporting software. For location
1613 and more information, read <file:Documentation/power/pm.txt> and the
1614 Battery Powered Linux mini-HOWTO, available from
1615 <http://www.tldp.org/docs.html#howto>.
1617 This driver does not spin down disk drives (see the hdparm(8)
1618 manpage ("man 8 hdparm") for that), and it doesn't turn off
1619 VESA-compliant "green" monitors.
1621 This driver does not support the TI 4000M TravelMate and the ACER
1622 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1623 desktop machines also don't have compliant BIOSes, and this driver
1624 may cause those machines to panic during the boot phase.
1626 Generally, if you don't have a battery in your machine, there isn't
1627 much point in using this driver and you should say N. If you get
1628 random kernel OOPSes or reboots that don't seem to be related to
1629 anything, try disabling/enabling this option (or disabling/enabling
1632 Some other things you should try when experiencing seemingly random,
1635 1) make sure that you have enough swap space and that it is
1637 2) pass the "no-hlt" option to the kernel
1638 3) switch on floating point emulation in the kernel and pass
1639 the "no387" option to the kernel
1640 4) pass the "floppy=nodma" option to the kernel
1641 5) pass the "mem=4M" option to the kernel (thereby disabling
1642 all but the first 4 MB of RAM)
1643 6) make sure that the CPU is not over clocked.
1644 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1645 8) disable the cache from your BIOS settings
1646 9) install a fan for the video card or exchange video RAM
1647 10) install a better fan for the CPU
1648 11) exchange RAM chips
1649 12) exchange the motherboard.
1651 To compile this driver as a module, choose M here: the
1652 module will be called apm.
1656 config APM_IGNORE_USER_SUSPEND
1657 bool "Ignore USER SUSPEND"
1659 This option will ignore USER SUSPEND requests. On machines with a
1660 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1661 series notebooks, it is necessary to say Y because of a BIOS bug.
1663 config APM_DO_ENABLE
1664 bool "Enable PM at boot time"
1666 Enable APM features at boot time. From page 36 of the APM BIOS
1667 specification: "When disabled, the APM BIOS does not automatically
1668 power manage devices, enter the Standby State, enter the Suspend
1669 State, or take power saving steps in response to CPU Idle calls."
1670 This driver will make CPU Idle calls when Linux is idle (unless this
1671 feature is turned off -- see "Do CPU IDLE calls", below). This
1672 should always save battery power, but more complicated APM features
1673 will be dependent on your BIOS implementation. You may need to turn
1674 this option off if your computer hangs at boot time when using APM
1675 support, or if it beeps continuously instead of suspending. Turn
1676 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1677 T400CDT. This is off by default since most machines do fine without
1681 bool "Make CPU Idle calls when idle"
1683 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1684 On some machines, this can activate improved power savings, such as
1685 a slowed CPU clock rate, when the machine is idle. These idle calls
1686 are made after the idle loop has run for some length of time (e.g.,
1687 333 mS). On some machines, this will cause a hang at boot time or
1688 whenever the CPU becomes idle. (On machines with more than one CPU,
1689 this option does nothing.)
1691 config APM_DISPLAY_BLANK
1692 bool "Enable console blanking using APM"
1694 Enable console blanking using the APM. Some laptops can use this to
1695 turn off the LCD backlight when the screen blanker of the Linux
1696 virtual console blanks the screen. Note that this is only used by
1697 the virtual console screen blanker, and won't turn off the backlight
1698 when using the X Window system. This also doesn't have anything to
1699 do with your VESA-compliant power-saving monitor. Further, this
1700 option doesn't work for all laptops -- it might not turn off your
1701 backlight at all, or it might print a lot of errors to the console,
1702 especially if you are using gpm.
1704 config APM_ALLOW_INTS
1705 bool "Allow interrupts during APM BIOS calls"
1707 Normally we disable external interrupts while we are making calls to
1708 the APM BIOS as a measure to lessen the effects of a badly behaving
1709 BIOS implementation. The BIOS should reenable interrupts if it
1710 needs to. Unfortunately, some BIOSes do not -- especially those in
1711 many of the newer IBM Thinkpads. If you experience hangs when you
1712 suspend, try setting this to Y. Otherwise, say N.
1716 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1718 source "drivers/cpuidle/Kconfig"
1720 source "drivers/idle/Kconfig"
1725 menu "Bus options (PCI etc.)"
1730 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1732 Find out whether you have a PCI motherboard. PCI is the name of a
1733 bus system, i.e. the way the CPU talks to the other stuff inside
1734 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1735 VESA. If you have PCI, say Y, otherwise N.
1738 prompt "PCI access mode"
1739 depends on X86_32 && PCI
1742 On PCI systems, the BIOS can be used to detect the PCI devices and
1743 determine their configuration. However, some old PCI motherboards
1744 have BIOS bugs and may crash if this is done. Also, some embedded
1745 PCI-based systems don't have any BIOS at all. Linux can also try to
1746 detect the PCI hardware directly without using the BIOS.
1748 With this option, you can specify how Linux should detect the
1749 PCI devices. If you choose "BIOS", the BIOS will be used,
1750 if you choose "Direct", the BIOS won't be used, and if you
1751 choose "MMConfig", then PCI Express MMCONFIG will be used.
1752 If you choose "Any", the kernel will try MMCONFIG, then the
1753 direct access method and falls back to the BIOS if that doesn't
1754 work. If unsure, go with the default, which is "Any".
1759 config PCI_GOMMCONFIG
1776 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1778 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1781 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1785 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1789 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1796 bool "Support mmconfig PCI config space access"
1797 depends on X86_64 && PCI && ACPI
1800 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1801 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1803 DMA remapping (DMAR) devices support enables independent address
1804 translations for Direct Memory Access (DMA) from devices.
1805 These DMA remapping devices are reported via ACPI tables
1806 and include PCI device scope covered by these DMA
1811 prompt "Support for Graphics workaround"
1814 Current Graphics drivers tend to use physical address
1815 for DMA and avoid using DMA APIs. Setting this config
1816 option permits the IOMMU driver to set a unity map for
1817 all the OS-visible memory. Hence the driver can continue
1818 to use physical addresses for DMA.
1820 config DMAR_FLOPPY_WA
1824 Floppy disk drivers are know to bypass DMA API calls
1825 thereby failing to work when IOMMU is enabled. This
1826 workaround will setup a 1:1 mapping for the first
1827 16M to make floppy (an ISA device) work.
1830 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1831 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1833 Supports Interrupt remapping for IO-APIC and MSI devices.
1834 To use x2apic mode in the CPU's which support x2APIC enhancements or
1835 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1837 source "drivers/pci/pcie/Kconfig"
1839 source "drivers/pci/Kconfig"
1841 # x86_64 have no ISA slots, but do have ISA-style DMA.
1849 depends on !X86_VOYAGER
1851 Find out whether you have ISA slots on your motherboard. ISA is the
1852 name of a bus system, i.e. the way the CPU talks to the other stuff
1853 inside your box. Other bus systems are PCI, EISA, MicroChannel
1854 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1855 newer boards don't support it. If you have ISA, say Y, otherwise N.
1861 The Extended Industry Standard Architecture (EISA) bus was
1862 developed as an open alternative to the IBM MicroChannel bus.
1864 The EISA bus provided some of the features of the IBM MicroChannel
1865 bus while maintaining backward compatibility with cards made for
1866 the older ISA bus. The EISA bus saw limited use between 1988 and
1867 1995 when it was made obsolete by the PCI bus.
1869 Say Y here if you are building a kernel for an EISA-based machine.
1873 source "drivers/eisa/Kconfig"
1876 bool "MCA support" if !X86_VOYAGER
1877 default y if X86_VOYAGER
1879 MicroChannel Architecture is found in some IBM PS/2 machines and
1880 laptops. It is a bus system similar to PCI or ISA. See
1881 <file:Documentation/mca.txt> (and especially the web page given
1882 there) before attempting to build an MCA bus kernel.
1884 source "drivers/mca/Kconfig"
1887 tristate "NatSemi SCx200 support"
1888 depends on !X86_VOYAGER
1890 This provides basic support for National Semiconductor's
1891 (now AMD's) Geode processors. The driver probes for the
1892 PCI-IDs of several on-chip devices, so its a good dependency
1893 for other scx200_* drivers.
1895 If compiled as a module, the driver is named scx200.
1897 config SCx200HR_TIMER
1898 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1899 depends on SCx200 && GENERIC_TIME
1902 This driver provides a clocksource built upon the on-chip
1903 27MHz high-resolution timer. Its also a workaround for
1904 NSC Geode SC-1100's buggy TSC, which loses time when the
1905 processor goes idle (as is done by the scheduler). The
1906 other workaround is idle=poll boot option.
1908 config GEODE_MFGPT_TIMER
1910 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1911 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1913 This driver provides a clock event source based on the MFGPT
1914 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1915 MFGPTs have a better resolution and max interval than the
1916 generic PIT, and are suitable for use as high-res timers.
1919 bool "One Laptop Per Child support"
1922 Add support for detecting the unique features of the OLPC
1929 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1931 source "drivers/pcmcia/Kconfig"
1933 source "drivers/pci/hotplug/Kconfig"
1938 menu "Executable file formats / Emulations"
1940 source "fs/Kconfig.binfmt"
1942 config IA32_EMULATION
1943 bool "IA32 Emulation"
1945 select COMPAT_BINFMT_ELF
1947 Include code to run 32-bit programs under a 64-bit kernel. You should
1948 likely turn this on, unless you're 100% sure that you don't have any
1949 32-bit programs left.
1952 tristate "IA32 a.out support"
1953 depends on IA32_EMULATION
1955 Support old a.out binaries in the 32bit emulation.
1959 depends on IA32_EMULATION
1961 config COMPAT_FOR_U64_ALIGNMENT
1965 config SYSVIPC_COMPAT
1967 depends on COMPAT && SYSVIPC
1972 config HAVE_ATOMIC_IOMAP
1976 source "net/Kconfig"
1978 source "drivers/Kconfig"
1980 source "drivers/firmware/Kconfig"
1984 source "arch/x86/Kconfig.debug"
1986 source "security/Kconfig"
1988 source "crypto/Kconfig"
1990 source "arch/x86/kvm/Kconfig"
1992 source "lib/Kconfig"
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