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 HAVE_KRETPROBES
31 select HAVE_FTRACE_MCOUNT_RECORD
32 select HAVE_DYNAMIC_FTRACE
33 select HAVE_FUNCTION_TRACER
34 select HAVE_FUNCTION_GRAPH_TRACER
35 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
36 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
37 select HAVE_ARCH_KGDB if !X86_VOYAGER
38 select HAVE_ARCH_TRACEHOOK
39 select HAVE_GENERIC_DMA_COHERENT if X86_32
40 select HAVE_EFFICIENT_UNALIGNED_ACCESS
41 select USER_STACKTRACE_SUPPORT
45 default "arch/x86/configs/i386_defconfig" if X86_32
46 default "arch/x86/configs/x86_64_defconfig" if X86_64
51 config GENERIC_CMOS_UPDATE
54 config CLOCKSOURCE_WATCHDOG
57 config GENERIC_CLOCKEVENTS
60 config GENERIC_CLOCKEVENTS_BROADCAST
62 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
64 config LOCKDEP_SUPPORT
67 config STACKTRACE_SUPPORT
70 config HAVE_LATENCYTOP_SUPPORT
73 config FAST_CMPXCHG_LOCAL
86 config GENERIC_ISA_DMA
95 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
97 config GENERIC_BUG_RELATIVE_POINTERS
100 config GENERIC_HWEIGHT
106 config ARCH_MAY_HAVE_PC_FDC
109 config RWSEM_GENERIC_SPINLOCK
112 config RWSEM_XCHGADD_ALGORITHM
115 config ARCH_HAS_CPU_IDLE_WAIT
118 config GENERIC_CALIBRATE_DELAY
121 config GENERIC_TIME_VSYSCALL
125 config ARCH_HAS_CPU_RELAX
128 config ARCH_HAS_DEFAULT_IDLE
131 config ARCH_HAS_CACHE_LINE_SIZE
134 config HAVE_SETUP_PER_CPU_AREA
135 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
137 config HAVE_CPUMASK_OF_CPU_MAP
140 config ARCH_HIBERNATION_POSSIBLE
142 depends on !SMP || !X86_VOYAGER
144 config ARCH_SUSPEND_POSSIBLE
146 depends on !X86_VOYAGER
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
178 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
181 config USE_GENERIC_SMP_HELPERS
187 depends on X86_32 && SMP
191 depends on X86_64 && SMP
196 depends on (X86_32 && !X86_VOYAGER) || X86_64
199 config X86_BIOS_REBOOT
201 depends on !X86_VOYAGER
204 config X86_TRAMPOLINE
206 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
211 source "init/Kconfig"
212 source "kernel/Kconfig.freezer"
214 menu "Processor type and features"
216 source "kernel/time/Kconfig"
219 bool "Symmetric multi-processing support"
221 This enables support for systems with more than one CPU. If you have
222 a system with only one CPU, like most personal computers, say N. If
223 you have a system with more than one CPU, say Y.
225 If you say N here, the kernel will run on single and multiprocessor
226 machines, but will use only one CPU of a multiprocessor machine. If
227 you say Y here, the kernel will run on many, but not all,
228 singleprocessor machines. On a singleprocessor machine, the kernel
229 will run faster if you say N here.
231 Note that if you say Y here and choose architecture "586" or
232 "Pentium" under "Processor family", the kernel will not work on 486
233 architectures. Similarly, multiprocessor kernels for the "PPro"
234 architecture may not work on all Pentium based boards.
236 People using multiprocessor machines who say Y here should also say
237 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
238 Management" code will be disabled if you say Y here.
240 See also <file:Documentation/i386/IO-APIC.txt>,
241 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
242 <http://www.tldp.org/docs.html#howto>.
244 If you don't know what to do here, say N.
246 config X86_HAS_BOOT_CPU_ID
248 depends on X86_VOYAGER
251 bool "Support sparse irq numbering"
252 depends on PCI_MSI || HT_IRQ
254 This enables support for sparse irqs. This is useful for distro
255 kernels that want to define a high CONFIG_NR_CPUS value but still
256 want to have low kernel memory footprint on smaller machines.
258 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
259 out the irq_desc[] array in a more NUMA-friendly way. )
261 If you don't know what to do here, say N.
263 config NUMA_MIGRATE_IRQ_DESC
264 bool "Move irq desc when changing irq smp_affinity"
265 depends on SPARSE_IRQ && NUMA
268 This enables moving irq_desc to cpu/node that irq will use handled.
270 If you don't know what to do here, say N.
272 config X86_FIND_SMP_CONFIG
274 depends on X86_MPPARSE || X86_VOYAGER
277 bool "Enable MPS table" if ACPI
279 depends on X86_LOCAL_APIC
281 For old smp systems that do not have proper acpi support. Newer systems
282 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
285 prompt "Subarchitecture Type"
291 Choose this option if your computer is a standard PC or compatible.
297 Select this for an AMD Elan processor.
299 Do not use this option for K6/Athlon/Opteron processors!
301 If unsure, choose "PC-compatible" instead.
305 depends on X86_32 && (SMP || BROKEN) && !PCI
307 Voyager is an MCA-based 32-way capable SMP architecture proprietary
308 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
312 If you do not specifically know you have a Voyager based machine,
313 say N here, otherwise the kernel you build will not be bootable.
315 config X86_GENERICARCH
316 bool "Generic architecture"
319 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
320 subarchitectures. It is intended for a generic binary kernel.
321 if you select them all, kernel will probe it one by one. and will
327 bool "NUMAQ (IBM/Sequent)"
328 depends on SMP && X86_32 && PCI && X86_MPPARSE
331 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
332 NUMA multiquad box. This changes the way that processors are
333 bootstrapped, and uses Clustered Logical APIC addressing mode instead
334 of Flat Logical. You will need a new lynxer.elf file to flash your
335 firmware with - send email to <Martin.Bligh@us.ibm.com>.
338 bool "Summit/EXA (IBM x440)"
339 depends on X86_32 && SMP
341 This option is needed for IBM systems that use the Summit/EXA chipset.
342 In particular, it is needed for the x440.
345 bool "Support for Unisys ES7000 IA32 series"
346 depends on X86_32 && SMP
348 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
349 supposed to run on an IA32-based Unisys ES7000 system.
352 bool "Support for big SMP systems with more than 8 CPUs"
353 depends on X86_32 && SMP
355 This option is needed for the systems that have more than 8 CPUs
356 and if the system is not of any sub-arch type above.
361 bool "Support for ScaleMP vSMP"
363 depends on X86_64 && PCI
365 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
366 supposed to run on these EM64T-based machines. Only choose this option
367 if you have one of these machines.
372 bool "SGI 320/540 (Visual Workstation)"
373 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
375 The SGI Visual Workstation series is an IA32-based workstation
376 based on SGI systems chips with some legacy PC hardware attached.
378 Say Y here to create a kernel to run on the SGI 320 or 540.
380 A kernel compiled for the Visual Workstation will run on general
381 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
384 bool "RDC R-321x SoC"
387 select X86_REBOOTFIXUPS
389 This option is needed for RDC R-321x system-on-chip, also known
391 If you don't have one of these chips, you should say N here.
393 config SCHED_OMIT_FRAME_POINTER
395 prompt "Single-depth WCHAN output"
398 Calculate simpler /proc/<PID>/wchan values. If this option
399 is disabled then wchan values will recurse back to the
400 caller function. This provides more accurate wchan values,
401 at the expense of slightly more scheduling overhead.
403 If in doubt, say "Y".
405 menuconfig PARAVIRT_GUEST
406 bool "Paravirtualized guest support"
408 Say Y here to get to see options related to running Linux under
409 various hypervisors. This option alone does not add any kernel code.
411 If you say N, all options in this submenu will be skipped and disabled.
415 source "arch/x86/xen/Kconfig"
418 bool "VMI Guest support"
421 depends on !X86_VOYAGER
423 VMI provides a paravirtualized interface to the VMware ESX server
424 (it could be used by other hypervisors in theory too, but is not
425 at the moment), by linking the kernel to a GPL-ed ROM module
426 provided by the hypervisor.
429 bool "KVM paravirtualized clock"
431 select PARAVIRT_CLOCK
432 depends on !X86_VOYAGER
434 Turning on this option will allow you to run a paravirtualized clock
435 when running over the KVM hypervisor. Instead of relying on a PIT
436 (or probably other) emulation by the underlying device model, the host
437 provides the guest with timing infrastructure such as time of day, and
441 bool "KVM Guest support"
443 depends on !X86_VOYAGER
445 This option enables various optimizations for running under the KVM
448 source "arch/x86/lguest/Kconfig"
451 bool "Enable paravirtualization code"
452 depends on !X86_VOYAGER
454 This changes the kernel so it can modify itself when it is run
455 under a hypervisor, potentially improving performance significantly
456 over full virtualization. However, when run without a hypervisor
457 the kernel is theoretically slower and slightly larger.
459 config PARAVIRT_CLOCK
465 config PARAVIRT_DEBUG
466 bool "paravirt-ops debugging"
467 depends on PARAVIRT && DEBUG_KERNEL
469 Enable to debug paravirt_ops internals. Specifically, BUG if
470 a paravirt_op is missing when it is called.
475 This option adds a kernel parameter 'memtest', which allows memtest
477 memtest=0, mean disabled; -- default
478 memtest=1, mean do 1 test pattern;
480 memtest=4, mean do 4 test patterns.
481 If you are unsure how to answer this question, answer N.
483 config X86_SUMMIT_NUMA
485 depends on X86_32 && NUMA && X86_GENERICARCH
487 config X86_CYCLONE_TIMER
489 depends on X86_GENERICARCH
491 source "arch/x86/Kconfig.cpu"
495 prompt "HPET Timer Support" if X86_32
497 Use the IA-PC HPET (High Precision Event Timer) to manage
498 time in preference to the PIT and RTC, if a HPET is
500 HPET is the next generation timer replacing legacy 8254s.
501 The HPET provides a stable time base on SMP
502 systems, unlike the TSC, but it is more expensive to access,
503 as it is off-chip. You can find the HPET spec at
504 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
506 You can safely choose Y here. However, HPET will only be
507 activated if the platform and the BIOS support this feature.
508 Otherwise the 8254 will be used for timing services.
510 Choose N to continue using the legacy 8254 timer.
512 config HPET_EMULATE_RTC
514 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
516 # Mark as embedded because too many people got it wrong.
517 # The code disables itself when not needed.
520 bool "Enable DMI scanning" if EMBEDDED
522 Enabled scanning of DMI to identify machine quirks. Say Y
523 here unless you have verified that your setup is not
524 affected by entries in the DMI blacklist. Required by PNP
528 bool "GART IOMMU support" if EMBEDDED
532 depends on X86_64 && PCI
534 Support for full DMA access of devices with 32bit memory access only
535 on systems with more than 3GB. This is usually needed for USB,
536 sound, many IDE/SATA chipsets and some other devices.
537 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
538 based hardware IOMMU and a software bounce buffer based IOMMU used
539 on Intel systems and as fallback.
540 The code is only active when needed (enough memory and limited
541 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
545 bool "IBM Calgary IOMMU support"
547 depends on X86_64 && PCI && EXPERIMENTAL
549 Support for hardware IOMMUs in IBM's xSeries x366 and x460
550 systems. Needed to run systems with more than 3GB of memory
551 properly with 32-bit PCI devices that do not support DAC
552 (Double Address Cycle). Calgary also supports bus level
553 isolation, where all DMAs pass through the IOMMU. This
554 prevents them from going anywhere except their intended
555 destination. This catches hard-to-find kernel bugs and
556 mis-behaving drivers and devices that do not use the DMA-API
557 properly to set up their DMA buffers. The IOMMU can be
558 turned off at boot time with the iommu=off parameter.
559 Normally the kernel will make the right choice by itself.
562 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
564 prompt "Should Calgary be enabled by default?"
565 depends on CALGARY_IOMMU
567 Should Calgary be enabled by default? if you choose 'y', Calgary
568 will be used (if it exists). If you choose 'n', Calgary will not be
569 used even if it exists. If you choose 'n' and would like to use
570 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
574 bool "AMD IOMMU support"
577 depends on X86_64 && PCI && ACPI
579 With this option you can enable support for AMD IOMMU hardware in
580 your system. An IOMMU is a hardware component which provides
581 remapping of DMA memory accesses from devices. With an AMD IOMMU you
582 can isolate the the DMA memory of different devices and protect the
583 system from misbehaving device drivers or hardware.
585 You can find out if your system has an AMD IOMMU if you look into
586 your BIOS for an option to enable it or if you have an IVRS ACPI
589 config AMD_IOMMU_STATS
590 bool "Export AMD IOMMU statistics to debugfs"
594 This option enables code in the AMD IOMMU driver to collect various
595 statistics about whats happening in the driver and exports that
596 information to userspace via debugfs.
599 # need this always selected by IOMMU for the VIA workaround
603 Support for software bounce buffers used on x86-64 systems
604 which don't have a hardware IOMMU (e.g. the current generation
605 of Intel's x86-64 CPUs). Using this PCI devices which can only
606 access 32-bits of memory can be used on systems with more than
607 3 GB of memory. If unsure, say Y.
610 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
613 def_bool (AMD_IOMMU || DMAR)
616 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
617 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
618 select CPUMASK_OFFSTACK
621 Configure maximum number of CPUS and NUMA Nodes for this architecture.
625 int "Maximum number of CPUs" if SMP && !MAXSMP
626 range 2 512 if SMP && !MAXSMP
628 default "4096" if MAXSMP
629 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
632 This allows you to specify the maximum number of CPUs which this
633 kernel will support. The maximum supported value is 512 and the
634 minimum value which makes sense is 2.
636 This is purely to save memory - each supported CPU adds
637 approximately eight kilobytes to the kernel image.
640 bool "SMT (Hyperthreading) scheduler support"
643 SMT scheduler support improves the CPU scheduler's decision making
644 when dealing with Intel Pentium 4 chips with HyperThreading at a
645 cost of slightly increased overhead in some places. If unsure say
650 prompt "Multi-core scheduler support"
653 Multi-core scheduler support improves the CPU scheduler's decision
654 making when dealing with multi-core CPU chips at a cost of slightly
655 increased overhead in some places. If unsure say N here.
657 source "kernel/Kconfig.preempt"
660 bool "Local APIC support on uniprocessors"
661 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
663 A local APIC (Advanced Programmable Interrupt Controller) is an
664 integrated interrupt controller in the CPU. If you have a single-CPU
665 system which has a processor with a local APIC, you can say Y here to
666 enable and use it. If you say Y here even though your machine doesn't
667 have a local APIC, then the kernel will still run with no slowdown at
668 all. The local APIC supports CPU-generated self-interrupts (timer,
669 performance counters), and the NMI watchdog which detects hard
673 bool "IO-APIC support on uniprocessors"
674 depends on X86_UP_APIC
676 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
677 SMP-capable replacement for PC-style interrupt controllers. Most
678 SMP systems and many recent uniprocessor systems have one.
680 If you have a single-CPU system with an IO-APIC, you can say Y here
681 to use it. If you say Y here even though your machine doesn't have
682 an IO-APIC, then the kernel will still run with no slowdown at all.
684 config X86_LOCAL_APIC
686 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
690 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
692 config X86_VISWS_APIC
694 depends on X86_32 && X86_VISWS
696 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
697 bool "Reroute for broken boot IRQs"
699 depends on X86_IO_APIC
701 This option enables a workaround that fixes a source of
702 spurious interrupts. This is recommended when threaded
703 interrupt handling is used on systems where the generation of
704 superfluous "boot interrupts" cannot be disabled.
706 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
707 entry in the chipset's IO-APIC is masked (as, e.g. the RT
708 kernel does during interrupt handling). On chipsets where this
709 boot IRQ generation cannot be disabled, this workaround keeps
710 the original IRQ line masked so that only the equivalent "boot
711 IRQ" is delivered to the CPUs. The workaround also tells the
712 kernel to set up the IRQ handler on the boot IRQ line. In this
713 way only one interrupt is delivered to the kernel. Otherwise
714 the spurious second interrupt may cause the kernel to bring
715 down (vital) interrupt lines.
717 Only affects "broken" chipsets. Interrupt sharing may be
718 increased on these systems.
721 bool "Machine Check Exception"
722 depends on !X86_VOYAGER
724 Machine Check Exception support allows the processor to notify the
725 kernel if it detects a problem (e.g. overheating, component failure).
726 The action the kernel takes depends on the severity of the problem,
727 ranging from a warning message on the console, to halting the machine.
728 Your processor must be a Pentium or newer to support this - check the
729 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
730 have a design flaw which leads to false MCE events - hence MCE is
731 disabled on all P5 processors, unless explicitly enabled with "mce"
732 as a boot argument. Similarly, if MCE is built in and creates a
733 problem on some new non-standard machine, you can boot with "nomce"
734 to disable it. MCE support simply ignores non-MCE processors like
735 the 386 and 486, so nearly everyone can say Y here.
739 prompt "Intel MCE features"
740 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
742 Additional support for intel specific MCE features such as
747 prompt "AMD MCE features"
748 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
750 Additional support for AMD specific MCE features such as
751 the DRAM Error Threshold.
753 config X86_MCE_NONFATAL
754 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
755 depends on X86_32 && X86_MCE
757 Enabling this feature starts a timer that triggers every 5 seconds which
758 will look at the machine check registers to see if anything happened.
759 Non-fatal problems automatically get corrected (but still logged).
760 Disable this if you don't want to see these messages.
761 Seeing the messages this option prints out may be indicative of dying
762 or out-of-spec (ie, overclocked) hardware.
763 This option only does something on certain CPUs.
764 (AMD Athlon/Duron and Intel Pentium 4)
766 config X86_MCE_P4THERMAL
767 bool "check for P4 thermal throttling interrupt."
768 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
770 Enabling this feature will cause a message to be printed when the P4
771 enters thermal throttling.
774 bool "Enable VM86 support" if EMBEDDED
778 This option is required by programs like DOSEMU to run 16-bit legacy
779 code on X86 processors. It also may be needed by software like
780 XFree86 to initialize some video cards via BIOS. Disabling this
781 option saves about 6k.
784 tristate "Toshiba Laptop support"
787 This adds a driver to safely access the System Management Mode of
788 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
789 not work on models with a Phoenix BIOS. The System Management Mode
790 is used to set the BIOS and power saving options on Toshiba portables.
792 For information on utilities to make use of this driver see the
793 Toshiba Linux utilities web site at:
794 <http://www.buzzard.org.uk/toshiba/>.
796 Say Y if you intend to run this kernel on a Toshiba portable.
800 tristate "Dell laptop support"
802 This adds a driver to safely access the System Management Mode
803 of the CPU on the Dell Inspiron 8000. The System Management Mode
804 is used to read cpu temperature and cooling fan status and to
805 control the fans on the I8K portables.
807 This driver has been tested only on the Inspiron 8000 but it may
808 also work with other Dell laptops. You can force loading on other
809 models by passing the parameter `force=1' to the module. Use at
812 For information on utilities to make use of this driver see the
813 I8K Linux utilities web site at:
814 <http://people.debian.org/~dz/i8k/>
816 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
819 config X86_REBOOTFIXUPS
820 bool "Enable X86 board specific fixups for reboot"
823 This enables chipset and/or board specific fixups to be done
824 in order to get reboot to work correctly. This is only needed on
825 some combinations of hardware and BIOS. The symptom, for which
826 this config is intended, is when reboot ends with a stalled/hung
829 Currently, the only fixup is for the Geode machines using
830 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
832 Say Y if you want to enable the fixup. Currently, it's safe to
833 enable this option even if you don't need it.
837 tristate "/dev/cpu/microcode - microcode support"
840 If you say Y here, you will be able to update the microcode on
841 certain Intel and AMD processors. The Intel support is for the
842 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
843 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
844 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
845 You will obviously need the actual microcode binary data itself
846 which is not shipped with the Linux kernel.
848 This option selects the general module only, you need to select
849 at least one vendor specific module as well.
851 To compile this driver as a module, choose M here: the
852 module will be called microcode.
854 config MICROCODE_INTEL
855 bool "Intel microcode patch loading support"
860 This options enables microcode patch loading support for Intel
863 For latest news and information on obtaining all the required
864 Intel ingredients for this driver, check:
865 <http://www.urbanmyth.org/microcode/>.
868 bool "AMD microcode patch loading support"
872 If you select this option, microcode patch loading support for AMD
873 processors will be enabled.
875 config MICROCODE_OLD_INTERFACE
880 tristate "/dev/cpu/*/msr - Model-specific register support"
882 This device gives privileged processes access to the x86
883 Model-Specific Registers (MSRs). It is a character device with
884 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
885 MSR accesses are directed to a specific CPU on multi-processor
889 tristate "/dev/cpu/*/cpuid - CPU information support"
891 This device gives processes access to the x86 CPUID instruction to
892 be executed on a specific processor. It is a character device
893 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
897 prompt "High Memory Support"
898 default HIGHMEM4G if !X86_NUMAQ
899 default HIGHMEM64G if X86_NUMAQ
904 depends on !X86_NUMAQ
906 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
907 However, the address space of 32-bit x86 processors is only 4
908 Gigabytes large. That means that, if you have a large amount of
909 physical memory, not all of it can be "permanently mapped" by the
910 kernel. The physical memory that's not permanently mapped is called
913 If you are compiling a kernel which will never run on a machine with
914 more than 1 Gigabyte total physical RAM, answer "off" here (default
915 choice and suitable for most users). This will result in a "3GB/1GB"
916 split: 3GB are mapped so that each process sees a 3GB virtual memory
917 space and the remaining part of the 4GB virtual memory space is used
918 by the kernel to permanently map as much physical memory as
921 If the machine has between 1 and 4 Gigabytes physical RAM, then
924 If more than 4 Gigabytes is used then answer "64GB" here. This
925 selection turns Intel PAE (Physical Address Extension) mode on.
926 PAE implements 3-level paging on IA32 processors. PAE is fully
927 supported by Linux, PAE mode is implemented on all recent Intel
928 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
929 then the kernel will not boot on CPUs that don't support PAE!
931 The actual amount of total physical memory will either be
932 auto detected or can be forced by using a kernel command line option
933 such as "mem=256M". (Try "man bootparam" or see the documentation of
934 your boot loader (lilo or loadlin) about how to pass options to the
935 kernel at boot time.)
937 If unsure, say "off".
941 depends on !X86_NUMAQ
943 Select this if you have a 32-bit processor and between 1 and 4
944 gigabytes of physical RAM.
948 depends on !M386 && !M486
951 Select this if you have a 32-bit processor and more than 4
952 gigabytes of physical RAM.
957 depends on EXPERIMENTAL
958 prompt "Memory split" if EMBEDDED
962 Select the desired split between kernel and user memory.
964 If the address range available to the kernel is less than the
965 physical memory installed, the remaining memory will be available
966 as "high memory". Accessing high memory is a little more costly
967 than low memory, as it needs to be mapped into the kernel first.
968 Note that increasing the kernel address space limits the range
969 available to user programs, making the address space there
970 tighter. Selecting anything other than the default 3G/1G split
971 will also likely make your kernel incompatible with binary-only
974 If you are not absolutely sure what you are doing, leave this
978 bool "3G/1G user/kernel split"
979 config VMSPLIT_3G_OPT
981 bool "3G/1G user/kernel split (for full 1G low memory)"
983 bool "2G/2G user/kernel split"
984 config VMSPLIT_2G_OPT
986 bool "2G/2G user/kernel split (for full 2G low memory)"
988 bool "1G/3G user/kernel split"
993 default 0xB0000000 if VMSPLIT_3G_OPT
994 default 0x80000000 if VMSPLIT_2G
995 default 0x78000000 if VMSPLIT_2G_OPT
996 default 0x40000000 if VMSPLIT_1G
1002 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1005 bool "PAE (Physical Address Extension) Support"
1006 depends on X86_32 && !HIGHMEM4G
1008 PAE is required for NX support, and furthermore enables
1009 larger swapspace support for non-overcommit purposes. It
1010 has the cost of more pagetable lookup overhead, and also
1011 consumes more pagetable space per process.
1013 config ARCH_PHYS_ADDR_T_64BIT
1014 def_bool X86_64 || X86_PAE
1016 config DIRECT_GBPAGES
1017 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1021 Allow the kernel linear mapping to use 1GB pages on CPUs that
1022 support it. This can improve the kernel's performance a tiny bit by
1023 reducing TLB pressure. If in doubt, say "Y".
1025 # Common NUMA Features
1027 bool "Numa Memory Allocation and Scheduler Support"
1029 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1031 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1033 Enable NUMA (Non Uniform Memory Access) support.
1035 The kernel will try to allocate memory used by a CPU on the
1036 local memory controller of the CPU and add some more
1037 NUMA awareness to the kernel.
1039 For 64-bit this is recommended if the system is Intel Core i7
1040 (or later), AMD Opteron, or EM64T NUMA.
1042 For 32-bit this is only needed on (rare) 32-bit-only platforms
1043 that support NUMA topologies, such as NUMAQ / Summit, or if you
1044 boot a 32-bit kernel on a 64-bit NUMA platform.
1046 Otherwise, you should say N.
1048 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1049 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1053 prompt "Old style AMD Opteron NUMA detection"
1054 depends on X86_64 && NUMA && PCI
1056 Enable K8 NUMA node topology detection. You should say Y here if
1057 you have a multi processor AMD K8 system. This uses an old
1058 method to read the NUMA configuration directly from the builtin
1059 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1060 instead, which also takes priority if both are compiled in.
1062 config X86_64_ACPI_NUMA
1064 prompt "ACPI NUMA detection"
1065 depends on X86_64 && NUMA && ACPI && PCI
1068 Enable ACPI SRAT based node topology detection.
1070 # Some NUMA nodes have memory ranges that span
1071 # other nodes. Even though a pfn is valid and
1072 # between a node's start and end pfns, it may not
1073 # reside on that node. See memmap_init_zone()
1075 config NODES_SPAN_OTHER_NODES
1077 depends on X86_64_ACPI_NUMA
1080 bool "NUMA emulation"
1081 depends on X86_64 && NUMA
1083 Enable NUMA emulation. A flat machine will be split
1084 into virtual nodes when booted with "numa=fake=N", where N is the
1085 number of nodes. This is only useful for debugging.
1088 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1090 default "9" if MAXSMP
1091 default "6" if X86_64
1092 default "4" if X86_NUMAQ
1094 depends on NEED_MULTIPLE_NODES
1096 Specify the maximum number of NUMA Nodes available on the target
1097 system. Increases memory reserved to accomodate various tables.
1099 config HAVE_ARCH_BOOTMEM_NODE
1101 depends on X86_32 && NUMA
1103 config ARCH_HAVE_MEMORY_PRESENT
1105 depends on X86_32 && DISCONTIGMEM
1107 config NEED_NODE_MEMMAP_SIZE
1109 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1111 config HAVE_ARCH_ALLOC_REMAP
1113 depends on X86_32 && NUMA
1115 config ARCH_FLATMEM_ENABLE
1117 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1119 config ARCH_DISCONTIGMEM_ENABLE
1121 depends on NUMA && X86_32
1123 config ARCH_DISCONTIGMEM_DEFAULT
1125 depends on NUMA && X86_32
1127 config ARCH_SPARSEMEM_DEFAULT
1131 config ARCH_SPARSEMEM_ENABLE
1133 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1134 select SPARSEMEM_STATIC if X86_32
1135 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1137 config ARCH_SELECT_MEMORY_MODEL
1139 depends on ARCH_SPARSEMEM_ENABLE
1141 config ARCH_MEMORY_PROBE
1143 depends on MEMORY_HOTPLUG
1148 bool "Allocate 3rd-level pagetables from highmem"
1149 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1151 The VM uses one page table entry for each page of physical memory.
1152 For systems with a lot of RAM, this can be wasteful of precious
1153 low memory. Setting this option will put user-space page table
1154 entries in high memory.
1156 config X86_CHECK_BIOS_CORRUPTION
1157 bool "Check for low memory corruption"
1159 Periodically check for memory corruption in low memory, which
1160 is suspected to be caused by BIOS. Even when enabled in the
1161 configuration, it is disabled at runtime. Enable it by
1162 setting "memory_corruption_check=1" on the kernel command
1163 line. By default it scans the low 64k of memory every 60
1164 seconds; see the memory_corruption_check_size and
1165 memory_corruption_check_period parameters in
1166 Documentation/kernel-parameters.txt to adjust this.
1168 When enabled with the default parameters, this option has
1169 almost no overhead, as it reserves a relatively small amount
1170 of memory and scans it infrequently. It both detects corruption
1171 and prevents it from affecting the running system.
1173 It is, however, intended as a diagnostic tool; if repeatable
1174 BIOS-originated corruption always affects the same memory,
1175 you can use memmap= to prevent the kernel from using that
1178 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1179 bool "Set the default setting of memory_corruption_check"
1180 depends on X86_CHECK_BIOS_CORRUPTION
1183 Set whether the default state of memory_corruption_check is
1186 config X86_RESERVE_LOW_64K
1187 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1190 Reserve the first 64K of physical RAM on BIOSes that are known
1191 to potentially corrupt that memory range. A numbers of BIOSes are
1192 known to utilize this area during suspend/resume, so it must not
1193 be used by the kernel.
1195 Set this to N if you are absolutely sure that you trust the BIOS
1196 to get all its memory reservations and usages right.
1198 If you have doubts about the BIOS (e.g. suspend/resume does not
1199 work or there's kernel crashes after certain hardware hotplug
1200 events) and it's not AMI or Phoenix, then you might want to enable
1201 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1202 corruption patterns.
1206 config MATH_EMULATION
1208 prompt "Math emulation" if X86_32
1210 Linux can emulate a math coprocessor (used for floating point
1211 operations) if you don't have one. 486DX and Pentium processors have
1212 a math coprocessor built in, 486SX and 386 do not, unless you added
1213 a 487DX or 387, respectively. (The messages during boot time can
1214 give you some hints here ["man dmesg"].) Everyone needs either a
1215 coprocessor or this emulation.
1217 If you don't have a math coprocessor, you need to say Y here; if you
1218 say Y here even though you have a coprocessor, the coprocessor will
1219 be used nevertheless. (This behavior can be changed with the kernel
1220 command line option "no387", which comes handy if your coprocessor
1221 is broken. Try "man bootparam" or see the documentation of your boot
1222 loader (lilo or loadlin) about how to pass options to the kernel at
1223 boot time.) This means that it is a good idea to say Y here if you
1224 intend to use this kernel on different machines.
1226 More information about the internals of the Linux math coprocessor
1227 emulation can be found in <file:arch/x86/math-emu/README>.
1229 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1230 kernel, it won't hurt.
1233 bool "MTRR (Memory Type Range Register) support"
1235 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1236 the Memory Type Range Registers (MTRRs) may be used to control
1237 processor access to memory ranges. This is most useful if you have
1238 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1239 allows bus write transfers to be combined into a larger transfer
1240 before bursting over the PCI/AGP bus. This can increase performance
1241 of image write operations 2.5 times or more. Saying Y here creates a
1242 /proc/mtrr file which may be used to manipulate your processor's
1243 MTRRs. Typically the X server should use this.
1245 This code has a reasonably generic interface so that similar
1246 control registers on other processors can be easily supported
1249 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1250 Registers (ARRs) which provide a similar functionality to MTRRs. For
1251 these, the ARRs are used to emulate the MTRRs.
1252 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1253 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1254 write-combining. All of these processors are supported by this code
1255 and it makes sense to say Y here if you have one of them.
1257 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1258 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1259 can lead to all sorts of problems, so it's good to say Y here.
1261 You can safely say Y even if your machine doesn't have MTRRs, you'll
1262 just add about 9 KB to your kernel.
1264 See <file:Documentation/x86/mtrr.txt> for more information.
1266 config MTRR_SANITIZER
1268 prompt "MTRR cleanup support"
1271 Convert MTRR layout from continuous to discrete, so X drivers can
1272 add writeback entries.
1274 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1275 The largest mtrr entry size for a continous block can be set with
1280 config MTRR_SANITIZER_ENABLE_DEFAULT
1281 int "MTRR cleanup enable value (0-1)"
1284 depends on MTRR_SANITIZER
1286 Enable mtrr cleanup default value
1288 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1289 int "MTRR cleanup spare reg num (0-7)"
1292 depends on MTRR_SANITIZER
1294 mtrr cleanup spare entries default, it can be changed via
1295 mtrr_spare_reg_nr=N on the kernel command line.
1299 prompt "x86 PAT support"
1302 Use PAT attributes to setup page level cache control.
1304 PATs are the modern equivalents of MTRRs and are much more
1305 flexible than MTRRs.
1307 Say N here if you see bootup problems (boot crash, boot hang,
1308 spontaneous reboots) or a non-working video driver.
1313 bool "EFI runtime service support"
1316 This enables the kernel to use EFI runtime services that are
1317 available (such as the EFI variable services).
1319 This option is only useful on systems that have EFI firmware.
1320 In addition, you should use the latest ELILO loader available
1321 at <http://elilo.sourceforge.net> in order to take advantage
1322 of EFI runtime services. However, even with this option, the
1323 resultant kernel should continue to boot on existing non-EFI
1328 prompt "Enable seccomp to safely compute untrusted bytecode"
1330 This kernel feature is useful for number crunching applications
1331 that may need to compute untrusted bytecode during their
1332 execution. By using pipes or other transports made available to
1333 the process as file descriptors supporting the read/write
1334 syscalls, it's possible to isolate those applications in
1335 their own address space using seccomp. Once seccomp is
1336 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1337 and the task is only allowed to execute a few safe syscalls
1338 defined by each seccomp mode.
1340 If unsure, say Y. Only embedded should say N here.
1342 config CC_STACKPROTECTOR
1343 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1344 depends on X86_64 && EXPERIMENTAL && BROKEN
1346 This option turns on the -fstack-protector GCC feature. This
1347 feature puts, at the beginning of critical functions, a canary
1348 value on the stack just before the return address, and validates
1349 the value just before actually returning. Stack based buffer
1350 overflows (that need to overwrite this return address) now also
1351 overwrite the canary, which gets detected and the attack is then
1352 neutralized via a kernel panic.
1354 This feature requires gcc version 4.2 or above, or a distribution
1355 gcc with the feature backported. Older versions are automatically
1356 detected and for those versions, this configuration option is ignored.
1358 config CC_STACKPROTECTOR_ALL
1359 bool "Use stack-protector for all functions"
1360 depends on CC_STACKPROTECTOR
1362 Normally, GCC only inserts the canary value protection for
1363 functions that use large-ish on-stack buffers. By enabling
1364 this option, GCC will be asked to do this for ALL functions.
1366 source kernel/Kconfig.hz
1369 bool "kexec system call"
1370 depends on X86_BIOS_REBOOT
1372 kexec is a system call that implements the ability to shutdown your
1373 current kernel, and to start another kernel. It is like a reboot
1374 but it is independent of the system firmware. And like a reboot
1375 you can start any kernel with it, not just Linux.
1377 The name comes from the similarity to the exec system call.
1379 It is an ongoing process to be certain the hardware in a machine
1380 is properly shutdown, so do not be surprised if this code does not
1381 initially work for you. It may help to enable device hotplugging
1382 support. As of this writing the exact hardware interface is
1383 strongly in flux, so no good recommendation can be made.
1386 bool "kernel crash dumps"
1387 depends on X86_64 || (X86_32 && HIGHMEM)
1389 Generate crash dump after being started by kexec.
1390 This should be normally only set in special crash dump kernels
1391 which are loaded in the main kernel with kexec-tools into
1392 a specially reserved region and then later executed after
1393 a crash by kdump/kexec. The crash dump kernel must be compiled
1394 to a memory address not used by the main kernel or BIOS using
1395 PHYSICAL_START, or it must be built as a relocatable image
1396 (CONFIG_RELOCATABLE=y).
1397 For more details see Documentation/kdump/kdump.txt
1400 bool "kexec jump (EXPERIMENTAL)"
1401 depends on EXPERIMENTAL
1402 depends on KEXEC && HIBERNATION && X86_32
1404 Jump between original kernel and kexeced kernel and invoke
1405 code in physical address mode via KEXEC
1407 config PHYSICAL_START
1408 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1409 default "0x1000000" if X86_NUMAQ
1410 default "0x200000" if X86_64
1413 This gives the physical address where the kernel is loaded.
1415 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1416 bzImage will decompress itself to above physical address and
1417 run from there. Otherwise, bzImage will run from the address where
1418 it has been loaded by the boot loader and will ignore above physical
1421 In normal kdump cases one does not have to set/change this option
1422 as now bzImage can be compiled as a completely relocatable image
1423 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1424 address. This option is mainly useful for the folks who don't want
1425 to use a bzImage for capturing the crash dump and want to use a
1426 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1427 to be specifically compiled to run from a specific memory area
1428 (normally a reserved region) and this option comes handy.
1430 So if you are using bzImage for capturing the crash dump, leave
1431 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1432 Otherwise if you plan to use vmlinux for capturing the crash dump
1433 change this value to start of the reserved region (Typically 16MB
1434 0x1000000). In other words, it can be set based on the "X" value as
1435 specified in the "crashkernel=YM@XM" command line boot parameter
1436 passed to the panic-ed kernel. Typically this parameter is set as
1437 crashkernel=64M@16M. Please take a look at
1438 Documentation/kdump/kdump.txt for more details about crash dumps.
1440 Usage of bzImage for capturing the crash dump is recommended as
1441 one does not have to build two kernels. Same kernel can be used
1442 as production kernel and capture kernel. Above option should have
1443 gone away after relocatable bzImage support is introduced. But it
1444 is present because there are users out there who continue to use
1445 vmlinux for dump capture. This option should go away down the
1448 Don't change this unless you know what you are doing.
1451 bool "Build a relocatable kernel (EXPERIMENTAL)"
1452 depends on EXPERIMENTAL
1454 This builds a kernel image that retains relocation information
1455 so it can be loaded someplace besides the default 1MB.
1456 The relocations tend to make the kernel binary about 10% larger,
1457 but are discarded at runtime.
1459 One use is for the kexec on panic case where the recovery kernel
1460 must live at a different physical address than the primary
1463 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1464 it has been loaded at and the compile time physical address
1465 (CONFIG_PHYSICAL_START) is ignored.
1467 config PHYSICAL_ALIGN
1469 prompt "Alignment value to which kernel should be aligned" if X86_32
1470 default "0x100000" if X86_32
1471 default "0x200000" if X86_64
1472 range 0x2000 0x400000
1474 This value puts the alignment restrictions on physical address
1475 where kernel is loaded and run from. Kernel is compiled for an
1476 address which meets above alignment restriction.
1478 If bootloader loads the kernel at a non-aligned address and
1479 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1480 address aligned to above value and run from there.
1482 If bootloader loads the kernel at a non-aligned address and
1483 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1484 load address and decompress itself to the address it has been
1485 compiled for and run from there. The address for which kernel is
1486 compiled already meets above alignment restrictions. Hence the
1487 end result is that kernel runs from a physical address meeting
1488 above alignment restrictions.
1490 Don't change this unless you know what you are doing.
1493 bool "Support for hot-pluggable CPUs"
1494 depends on SMP && HOTPLUG && !X86_VOYAGER
1496 Say Y here to allow turning CPUs off and on. CPUs can be
1497 controlled through /sys/devices/system/cpu.
1498 ( Note: power management support will enable this option
1499 automatically on SMP systems. )
1500 Say N if you want to disable CPU hotplug.
1504 prompt "Compat VDSO support"
1505 depends on X86_32 || IA32_EMULATION
1507 Map the 32-bit VDSO to the predictable old-style address too.
1509 Say N here if you are running a sufficiently recent glibc
1510 version (2.3.3 or later), to remove the high-mapped
1511 VDSO mapping and to exclusively use the randomized VDSO.
1516 bool "Built-in kernel command line"
1519 Allow for specifying boot arguments to the kernel at
1520 build time. On some systems (e.g. embedded ones), it is
1521 necessary or convenient to provide some or all of the
1522 kernel boot arguments with the kernel itself (that is,
1523 to not rely on the boot loader to provide them.)
1525 To compile command line arguments into the kernel,
1526 set this option to 'Y', then fill in the
1527 the boot arguments in CONFIG_CMDLINE.
1529 Systems with fully functional boot loaders (i.e. non-embedded)
1530 should leave this option set to 'N'.
1533 string "Built-in kernel command string"
1534 depends on CMDLINE_BOOL
1537 Enter arguments here that should be compiled into the kernel
1538 image and used at boot time. If the boot loader provides a
1539 command line at boot time, it is appended to this string to
1540 form the full kernel command line, when the system boots.
1542 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1543 change this behavior.
1545 In most cases, the command line (whether built-in or provided
1546 by the boot loader) should specify the device for the root
1549 config CMDLINE_OVERRIDE
1550 bool "Built-in command line overrides boot loader arguments"
1552 depends on CMDLINE_BOOL
1554 Set this option to 'Y' to have the kernel ignore the boot loader
1555 command line, and use ONLY the built-in command line.
1557 This is used to work around broken boot loaders. This should
1558 be set to 'N' under normal conditions.
1562 config ARCH_ENABLE_MEMORY_HOTPLUG
1564 depends on X86_64 || (X86_32 && HIGHMEM)
1566 config ARCH_ENABLE_MEMORY_HOTREMOVE
1568 depends on MEMORY_HOTPLUG
1570 config HAVE_ARCH_EARLY_PFN_TO_NID
1574 menu "Power management and ACPI options"
1575 depends on !X86_VOYAGER
1577 config ARCH_HIBERNATION_HEADER
1579 depends on X86_64 && HIBERNATION
1581 source "kernel/power/Kconfig"
1583 source "drivers/acpi/Kconfig"
1588 depends on APM || APM_MODULE
1591 tristate "APM (Advanced Power Management) BIOS support"
1592 depends on X86_32 && PM_SLEEP
1594 APM is a BIOS specification for saving power using several different
1595 techniques. This is mostly useful for battery powered laptops with
1596 APM compliant BIOSes. If you say Y here, the system time will be
1597 reset after a RESUME operation, the /proc/apm device will provide
1598 battery status information, and user-space programs will receive
1599 notification of APM "events" (e.g. battery status change).
1601 If you select "Y" here, you can disable actual use of the APM
1602 BIOS by passing the "apm=off" option to the kernel at boot time.
1604 Note that the APM support is almost completely disabled for
1605 machines with more than one CPU.
1607 In order to use APM, you will need supporting software. For location
1608 and more information, read <file:Documentation/power/pm.txt> and the
1609 Battery Powered Linux mini-HOWTO, available from
1610 <http://www.tldp.org/docs.html#howto>.
1612 This driver does not spin down disk drives (see the hdparm(8)
1613 manpage ("man 8 hdparm") for that), and it doesn't turn off
1614 VESA-compliant "green" monitors.
1616 This driver does not support the TI 4000M TravelMate and the ACER
1617 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1618 desktop machines also don't have compliant BIOSes, and this driver
1619 may cause those machines to panic during the boot phase.
1621 Generally, if you don't have a battery in your machine, there isn't
1622 much point in using this driver and you should say N. If you get
1623 random kernel OOPSes or reboots that don't seem to be related to
1624 anything, try disabling/enabling this option (or disabling/enabling
1627 Some other things you should try when experiencing seemingly random,
1630 1) make sure that you have enough swap space and that it is
1632 2) pass the "no-hlt" option to the kernel
1633 3) switch on floating point emulation in the kernel and pass
1634 the "no387" option to the kernel
1635 4) pass the "floppy=nodma" option to the kernel
1636 5) pass the "mem=4M" option to the kernel (thereby disabling
1637 all but the first 4 MB of RAM)
1638 6) make sure that the CPU is not over clocked.
1639 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1640 8) disable the cache from your BIOS settings
1641 9) install a fan for the video card or exchange video RAM
1642 10) install a better fan for the CPU
1643 11) exchange RAM chips
1644 12) exchange the motherboard.
1646 To compile this driver as a module, choose M here: the
1647 module will be called apm.
1651 config APM_IGNORE_USER_SUSPEND
1652 bool "Ignore USER SUSPEND"
1654 This option will ignore USER SUSPEND requests. On machines with a
1655 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1656 series notebooks, it is necessary to say Y because of a BIOS bug.
1658 config APM_DO_ENABLE
1659 bool "Enable PM at boot time"
1661 Enable APM features at boot time. From page 36 of the APM BIOS
1662 specification: "When disabled, the APM BIOS does not automatically
1663 power manage devices, enter the Standby State, enter the Suspend
1664 State, or take power saving steps in response to CPU Idle calls."
1665 This driver will make CPU Idle calls when Linux is idle (unless this
1666 feature is turned off -- see "Do CPU IDLE calls", below). This
1667 should always save battery power, but more complicated APM features
1668 will be dependent on your BIOS implementation. You may need to turn
1669 this option off if your computer hangs at boot time when using APM
1670 support, or if it beeps continuously instead of suspending. Turn
1671 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1672 T400CDT. This is off by default since most machines do fine without
1676 bool "Make CPU Idle calls when idle"
1678 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1679 On some machines, this can activate improved power savings, such as
1680 a slowed CPU clock rate, when the machine is idle. These idle calls
1681 are made after the idle loop has run for some length of time (e.g.,
1682 333 mS). On some machines, this will cause a hang at boot time or
1683 whenever the CPU becomes idle. (On machines with more than one CPU,
1684 this option does nothing.)
1686 config APM_DISPLAY_BLANK
1687 bool "Enable console blanking using APM"
1689 Enable console blanking using the APM. Some laptops can use this to
1690 turn off the LCD backlight when the screen blanker of the Linux
1691 virtual console blanks the screen. Note that this is only used by
1692 the virtual console screen blanker, and won't turn off the backlight
1693 when using the X Window system. This also doesn't have anything to
1694 do with your VESA-compliant power-saving monitor. Further, this
1695 option doesn't work for all laptops -- it might not turn off your
1696 backlight at all, or it might print a lot of errors to the console,
1697 especially if you are using gpm.
1699 config APM_ALLOW_INTS
1700 bool "Allow interrupts during APM BIOS calls"
1702 Normally we disable external interrupts while we are making calls to
1703 the APM BIOS as a measure to lessen the effects of a badly behaving
1704 BIOS implementation. The BIOS should reenable interrupts if it
1705 needs to. Unfortunately, some BIOSes do not -- especially those in
1706 many of the newer IBM Thinkpads. If you experience hangs when you
1707 suspend, try setting this to Y. Otherwise, say N.
1711 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1713 source "drivers/cpuidle/Kconfig"
1715 source "drivers/idle/Kconfig"
1720 menu "Bus options (PCI etc.)"
1725 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1727 Find out whether you have a PCI motherboard. PCI is the name of a
1728 bus system, i.e. the way the CPU talks to the other stuff inside
1729 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1730 VESA. If you have PCI, say Y, otherwise N.
1733 prompt "PCI access mode"
1734 depends on X86_32 && PCI
1737 On PCI systems, the BIOS can be used to detect the PCI devices and
1738 determine their configuration. However, some old PCI motherboards
1739 have BIOS bugs and may crash if this is done. Also, some embedded
1740 PCI-based systems don't have any BIOS at all. Linux can also try to
1741 detect the PCI hardware directly without using the BIOS.
1743 With this option, you can specify how Linux should detect the
1744 PCI devices. If you choose "BIOS", the BIOS will be used,
1745 if you choose "Direct", the BIOS won't be used, and if you
1746 choose "MMConfig", then PCI Express MMCONFIG will be used.
1747 If you choose "Any", the kernel will try MMCONFIG, then the
1748 direct access method and falls back to the BIOS if that doesn't
1749 work. If unsure, go with the default, which is "Any".
1754 config PCI_GOMMCONFIG
1771 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1773 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1776 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1780 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1784 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1791 bool "Support mmconfig PCI config space access"
1792 depends on X86_64 && PCI && ACPI
1795 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1796 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1798 DMA remapping (DMAR) devices support enables independent address
1799 translations for Direct Memory Access (DMA) from devices.
1800 These DMA remapping devices are reported via ACPI tables
1801 and include PCI device scope covered by these DMA
1806 prompt "Support for Graphics workaround"
1809 Current Graphics drivers tend to use physical address
1810 for DMA and avoid using DMA APIs. Setting this config
1811 option permits the IOMMU driver to set a unity map for
1812 all the OS-visible memory. Hence the driver can continue
1813 to use physical addresses for DMA.
1815 config DMAR_FLOPPY_WA
1819 Floppy disk drivers are know to bypass DMA API calls
1820 thereby failing to work when IOMMU is enabled. This
1821 workaround will setup a 1:1 mapping for the first
1822 16M to make floppy (an ISA device) work.
1825 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1826 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1828 Supports Interrupt remapping for IO-APIC and MSI devices.
1829 To use x2apic mode in the CPU's which support x2APIC enhancements or
1830 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1832 source "drivers/pci/pcie/Kconfig"
1834 source "drivers/pci/Kconfig"
1836 # x86_64 have no ISA slots, but do have ISA-style DMA.
1844 depends on !X86_VOYAGER
1846 Find out whether you have ISA slots on your motherboard. ISA is the
1847 name of a bus system, i.e. the way the CPU talks to the other stuff
1848 inside your box. Other bus systems are PCI, EISA, MicroChannel
1849 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1850 newer boards don't support it. If you have ISA, say Y, otherwise N.
1856 The Extended Industry Standard Architecture (EISA) bus was
1857 developed as an open alternative to the IBM MicroChannel bus.
1859 The EISA bus provided some of the features of the IBM MicroChannel
1860 bus while maintaining backward compatibility with cards made for
1861 the older ISA bus. The EISA bus saw limited use between 1988 and
1862 1995 when it was made obsolete by the PCI bus.
1864 Say Y here if you are building a kernel for an EISA-based machine.
1868 source "drivers/eisa/Kconfig"
1871 bool "MCA support" if !X86_VOYAGER
1872 default y if X86_VOYAGER
1874 MicroChannel Architecture is found in some IBM PS/2 machines and
1875 laptops. It is a bus system similar to PCI or ISA. See
1876 <file:Documentation/mca.txt> (and especially the web page given
1877 there) before attempting to build an MCA bus kernel.
1879 source "drivers/mca/Kconfig"
1882 tristate "NatSemi SCx200 support"
1883 depends on !X86_VOYAGER
1885 This provides basic support for National Semiconductor's
1886 (now AMD's) Geode processors. The driver probes for the
1887 PCI-IDs of several on-chip devices, so its a good dependency
1888 for other scx200_* drivers.
1890 If compiled as a module, the driver is named scx200.
1892 config SCx200HR_TIMER
1893 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1894 depends on SCx200 && GENERIC_TIME
1897 This driver provides a clocksource built upon the on-chip
1898 27MHz high-resolution timer. Its also a workaround for
1899 NSC Geode SC-1100's buggy TSC, which loses time when the
1900 processor goes idle (as is done by the scheduler). The
1901 other workaround is idle=poll boot option.
1903 config GEODE_MFGPT_TIMER
1905 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1906 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1908 This driver provides a clock event source based on the MFGPT
1909 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1910 MFGPTs have a better resolution and max interval than the
1911 generic PIT, and are suitable for use as high-res timers.
1914 bool "One Laptop Per Child support"
1917 Add support for detecting the unique features of the OLPC
1924 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1926 source "drivers/pcmcia/Kconfig"
1928 source "drivers/pci/hotplug/Kconfig"
1933 menu "Executable file formats / Emulations"
1935 source "fs/Kconfig.binfmt"
1937 config IA32_EMULATION
1938 bool "IA32 Emulation"
1940 select COMPAT_BINFMT_ELF
1942 Include code to run 32-bit programs under a 64-bit kernel. You should
1943 likely turn this on, unless you're 100% sure that you don't have any
1944 32-bit programs left.
1947 tristate "IA32 a.out support"
1948 depends on IA32_EMULATION
1950 Support old a.out binaries in the 32bit emulation.
1954 depends on IA32_EMULATION
1956 config COMPAT_FOR_U64_ALIGNMENT
1960 config SYSVIPC_COMPAT
1962 depends on COMPAT && SYSVIPC
1967 config HAVE_ATOMIC_IOMAP
1971 source "net/Kconfig"
1973 source "drivers/Kconfig"
1975 source "drivers/firmware/Kconfig"
1979 source "arch/x86/Kconfig.debug"
1981 source "security/Kconfig"
1983 source "crypto/Kconfig"
1985 source "arch/x86/kvm/Kconfig"
1987 source "lib/Kconfig"
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