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_HARDIRQS_NO__DO_IRQ
171 config GENERIC_IRQ_PROBE
175 config GENERIC_PENDING_IRQ
177 depends on GENERIC_HARDIRQS && SMP
182 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
185 config USE_GENERIC_SMP_HELPERS
191 depends on X86_32 && SMP
195 depends on X86_64 && SMP
200 depends on (X86_32 && !X86_VOYAGER) || X86_64
203 config X86_BIOS_REBOOT
205 depends on !X86_VOYAGER
208 config X86_TRAMPOLINE
210 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
215 source "init/Kconfig"
216 source "kernel/Kconfig.freezer"
218 menu "Processor type and features"
220 source "kernel/time/Kconfig"
223 bool "Symmetric multi-processing support"
225 This enables support for systems with more than one CPU. If you have
226 a system with only one CPU, like most personal computers, say N. If
227 you have a system with more than one CPU, say Y.
229 If you say N here, the kernel will run on single and multiprocessor
230 machines, but will use only one CPU of a multiprocessor machine. If
231 you say Y here, the kernel will run on many, but not all,
232 singleprocessor machines. On a singleprocessor machine, the kernel
233 will run faster if you say N here.
235 Note that if you say Y here and choose architecture "586" or
236 "Pentium" under "Processor family", the kernel will not work on 486
237 architectures. Similarly, multiprocessor kernels for the "PPro"
238 architecture may not work on all Pentium based boards.
240 People using multiprocessor machines who say Y here should also say
241 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
242 Management" code will be disabled if you say Y here.
244 See also <file:Documentation/i386/IO-APIC.txt>,
245 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
246 <http://www.tldp.org/docs.html#howto>.
248 If you don't know what to do here, say N.
250 config X86_HAS_BOOT_CPU_ID
252 depends on X86_VOYAGER
255 bool "Support sparse irq numbering"
256 depends on PCI_MSI || HT_IRQ
258 This enables support for sparse irqs. This is useful for distro
259 kernels that want to define a high CONFIG_NR_CPUS value but still
260 want to have low kernel memory footprint on smaller machines.
262 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
263 out the irq_desc[] array in a more NUMA-friendly way. )
265 If you don't know what to do here, say N.
267 config NUMA_MIGRATE_IRQ_DESC
268 bool "Move irq desc when changing irq smp_affinity"
269 depends on SPARSE_IRQ && NUMA
272 This enables moving irq_desc to cpu/node that irq will use handled.
274 If you don't know what to do here, say N.
276 config X86_FIND_SMP_CONFIG
278 depends on X86_MPPARSE || X86_VOYAGER
281 bool "Enable MPS table" if ACPI
283 depends on X86_LOCAL_APIC
285 For old smp systems that do not have proper acpi support. Newer systems
286 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
289 prompt "Subarchitecture Type"
295 Choose this option if your computer is a standard PC or compatible.
301 Select this for an AMD Elan processor.
303 Do not use this option for K6/Athlon/Opteron processors!
305 If unsure, choose "PC-compatible" instead.
309 depends on X86_32 && (SMP || BROKEN) && !PCI
311 Voyager is an MCA-based 32-way capable SMP architecture proprietary
312 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
316 If you do not specifically know you have a Voyager based machine,
317 say N here, otherwise the kernel you build will not be bootable.
319 config X86_GENERICARCH
320 bool "Generic architecture"
323 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
324 subarchitectures. It is intended for a generic binary kernel.
325 if you select them all, kernel will probe it one by one. and will
331 bool "NUMAQ (IBM/Sequent)"
332 depends on SMP && X86_32 && PCI && X86_MPPARSE
335 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
336 NUMA multiquad box. This changes the way that processors are
337 bootstrapped, and uses Clustered Logical APIC addressing mode instead
338 of Flat Logical. You will need a new lynxer.elf file to flash your
339 firmware with - send email to <Martin.Bligh@us.ibm.com>.
342 bool "Summit/EXA (IBM x440)"
343 depends on X86_32 && SMP
345 This option is needed for IBM systems that use the Summit/EXA chipset.
346 In particular, it is needed for the x440.
349 bool "Support for Unisys ES7000 IA32 series"
350 depends on X86_32 && SMP
352 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
353 supposed to run on an IA32-based Unisys ES7000 system.
356 bool "Support for big SMP systems with more than 8 CPUs"
357 depends on X86_32 && SMP
359 This option is needed for the systems that have more than 8 CPUs
360 and if the system is not of any sub-arch type above.
365 bool "Support for ScaleMP vSMP"
367 depends on X86_64 && PCI
369 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
370 supposed to run on these EM64T-based machines. Only choose this option
371 if you have one of these machines.
376 bool "SGI 320/540 (Visual Workstation)"
377 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
379 The SGI Visual Workstation series is an IA32-based workstation
380 based on SGI systems chips with some legacy PC hardware attached.
382 Say Y here to create a kernel to run on the SGI 320 or 540.
384 A kernel compiled for the Visual Workstation will run on general
385 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
388 bool "RDC R-321x SoC"
391 select X86_REBOOTFIXUPS
393 This option is needed for RDC R-321x system-on-chip, also known
395 If you don't have one of these chips, you should say N here.
397 config SCHED_OMIT_FRAME_POINTER
399 prompt "Single-depth WCHAN output"
402 Calculate simpler /proc/<PID>/wchan values. If this option
403 is disabled then wchan values will recurse back to the
404 caller function. This provides more accurate wchan values,
405 at the expense of slightly more scheduling overhead.
407 If in doubt, say "Y".
409 menuconfig PARAVIRT_GUEST
410 bool "Paravirtualized guest support"
412 Say Y here to get to see options related to running Linux under
413 various hypervisors. This option alone does not add any kernel code.
415 If you say N, all options in this submenu will be skipped and disabled.
419 source "arch/x86/xen/Kconfig"
422 bool "VMI Guest support"
425 depends on !X86_VOYAGER
427 VMI provides a paravirtualized interface to the VMware ESX server
428 (it could be used by other hypervisors in theory too, but is not
429 at the moment), by linking the kernel to a GPL-ed ROM module
430 provided by the hypervisor.
433 bool "KVM paravirtualized clock"
435 select PARAVIRT_CLOCK
436 depends on !X86_VOYAGER
438 Turning on this option will allow you to run a paravirtualized clock
439 when running over the KVM hypervisor. Instead of relying on a PIT
440 (or probably other) emulation by the underlying device model, the host
441 provides the guest with timing infrastructure such as time of day, and
445 bool "KVM Guest support"
447 depends on !X86_VOYAGER
449 This option enables various optimizations for running under the KVM
452 source "arch/x86/lguest/Kconfig"
455 bool "Enable paravirtualization code"
456 depends on !X86_VOYAGER
458 This changes the kernel so it can modify itself when it is run
459 under a hypervisor, potentially improving performance significantly
460 over full virtualization. However, when run without a hypervisor
461 the kernel is theoretically slower and slightly larger.
463 config PARAVIRT_CLOCK
469 config PARAVIRT_DEBUG
470 bool "paravirt-ops debugging"
471 depends on PARAVIRT && DEBUG_KERNEL
473 Enable to debug paravirt_ops internals. Specifically, BUG if
474 a paravirt_op is missing when it is called.
479 This option adds a kernel parameter 'memtest', which allows memtest
481 memtest=0, mean disabled; -- default
482 memtest=1, mean do 1 test pattern;
484 memtest=4, mean do 4 test patterns.
485 If you are unsure how to answer this question, answer N.
487 config X86_SUMMIT_NUMA
489 depends on X86_32 && NUMA && X86_GENERICARCH
491 config X86_CYCLONE_TIMER
493 depends on X86_GENERICARCH
495 source "arch/x86/Kconfig.cpu"
499 prompt "HPET Timer Support" if X86_32
501 Use the IA-PC HPET (High Precision Event Timer) to manage
502 time in preference to the PIT and RTC, if a HPET is
504 HPET is the next generation timer replacing legacy 8254s.
505 The HPET provides a stable time base on SMP
506 systems, unlike the TSC, but it is more expensive to access,
507 as it is off-chip. You can find the HPET spec at
508 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
510 You can safely choose Y here. However, HPET will only be
511 activated if the platform and the BIOS support this feature.
512 Otherwise the 8254 will be used for timing services.
514 Choose N to continue using the legacy 8254 timer.
516 config HPET_EMULATE_RTC
518 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
520 # Mark as embedded because too many people got it wrong.
521 # The code disables itself when not needed.
524 bool "Enable DMI scanning" if EMBEDDED
526 Enabled scanning of DMI to identify machine quirks. Say Y
527 here unless you have verified that your setup is not
528 affected by entries in the DMI blacklist. Required by PNP
532 bool "GART IOMMU support" if EMBEDDED
536 depends on X86_64 && PCI
538 Support for full DMA access of devices with 32bit memory access only
539 on systems with more than 3GB. This is usually needed for USB,
540 sound, many IDE/SATA chipsets and some other devices.
541 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
542 based hardware IOMMU and a software bounce buffer based IOMMU used
543 on Intel systems and as fallback.
544 The code is only active when needed (enough memory and limited
545 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
549 bool "IBM Calgary IOMMU support"
551 depends on X86_64 && PCI && EXPERIMENTAL
553 Support for hardware IOMMUs in IBM's xSeries x366 and x460
554 systems. Needed to run systems with more than 3GB of memory
555 properly with 32-bit PCI devices that do not support DAC
556 (Double Address Cycle). Calgary also supports bus level
557 isolation, where all DMAs pass through the IOMMU. This
558 prevents them from going anywhere except their intended
559 destination. This catches hard-to-find kernel bugs and
560 mis-behaving drivers and devices that do not use the DMA-API
561 properly to set up their DMA buffers. The IOMMU can be
562 turned off at boot time with the iommu=off parameter.
563 Normally the kernel will make the right choice by itself.
566 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
568 prompt "Should Calgary be enabled by default?"
569 depends on CALGARY_IOMMU
571 Should Calgary be enabled by default? if you choose 'y', Calgary
572 will be used (if it exists). If you choose 'n', Calgary will not be
573 used even if it exists. If you choose 'n' and would like to use
574 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
578 bool "AMD IOMMU support"
581 depends on X86_64 && PCI && ACPI
583 With this option you can enable support for AMD IOMMU hardware in
584 your system. An IOMMU is a hardware component which provides
585 remapping of DMA memory accesses from devices. With an AMD IOMMU you
586 can isolate the the DMA memory of different devices and protect the
587 system from misbehaving device drivers or hardware.
589 You can find out if your system has an AMD IOMMU if you look into
590 your BIOS for an option to enable it or if you have an IVRS ACPI
593 config AMD_IOMMU_STATS
594 bool "Export AMD IOMMU statistics to debugfs"
598 This option enables code in the AMD IOMMU driver to collect various
599 statistics about whats happening in the driver and exports that
600 information to userspace via debugfs.
603 # need this always selected by IOMMU for the VIA workaround
607 Support for software bounce buffers used on x86-64 systems
608 which don't have a hardware IOMMU (e.g. the current generation
609 of Intel's x86-64 CPUs). Using this PCI devices which can only
610 access 32-bits of memory can be used on systems with more than
611 3 GB of memory. If unsure, say Y.
614 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
617 def_bool (AMD_IOMMU || DMAR)
620 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
621 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
622 select CPUMASK_OFFSTACK
625 Configure maximum number of CPUS and NUMA Nodes for this architecture.
629 int "Maximum number of CPUs" if SMP && !MAXSMP
630 range 2 512 if SMP && !MAXSMP
632 default "4096" if MAXSMP
633 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
636 This allows you to specify the maximum number of CPUs which this
637 kernel will support. The maximum supported value is 512 and the
638 minimum value which makes sense is 2.
640 This is purely to save memory - each supported CPU adds
641 approximately eight kilobytes to the kernel image.
644 bool "SMT (Hyperthreading) scheduler support"
647 SMT scheduler support improves the CPU scheduler's decision making
648 when dealing with Intel Pentium 4 chips with HyperThreading at a
649 cost of slightly increased overhead in some places. If unsure say
654 prompt "Multi-core scheduler support"
657 Multi-core scheduler support improves the CPU scheduler's decision
658 making when dealing with multi-core CPU chips at a cost of slightly
659 increased overhead in some places. If unsure say N here.
661 source "kernel/Kconfig.preempt"
664 bool "Local APIC support on uniprocessors"
665 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
667 A local APIC (Advanced Programmable Interrupt Controller) is an
668 integrated interrupt controller in the CPU. If you have a single-CPU
669 system which has a processor with a local APIC, you can say Y here to
670 enable and use it. If you say Y here even though your machine doesn't
671 have a local APIC, then the kernel will still run with no slowdown at
672 all. The local APIC supports CPU-generated self-interrupts (timer,
673 performance counters), and the NMI watchdog which detects hard
677 bool "IO-APIC support on uniprocessors"
678 depends on X86_UP_APIC
680 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
681 SMP-capable replacement for PC-style interrupt controllers. Most
682 SMP systems and many recent uniprocessor systems have one.
684 If you have a single-CPU system with an IO-APIC, you can say Y here
685 to use it. If you say Y here even though your machine doesn't have
686 an IO-APIC, then the kernel will still run with no slowdown at all.
688 config X86_LOCAL_APIC
690 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
694 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
696 config X86_VISWS_APIC
698 depends on X86_32 && X86_VISWS
700 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
701 bool "Reroute for broken boot IRQs"
703 depends on X86_IO_APIC
705 This option enables a workaround that fixes a source of
706 spurious interrupts. This is recommended when threaded
707 interrupt handling is used on systems where the generation of
708 superfluous "boot interrupts" cannot be disabled.
710 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
711 entry in the chipset's IO-APIC is masked (as, e.g. the RT
712 kernel does during interrupt handling). On chipsets where this
713 boot IRQ generation cannot be disabled, this workaround keeps
714 the original IRQ line masked so that only the equivalent "boot
715 IRQ" is delivered to the CPUs. The workaround also tells the
716 kernel to set up the IRQ handler on the boot IRQ line. In this
717 way only one interrupt is delivered to the kernel. Otherwise
718 the spurious second interrupt may cause the kernel to bring
719 down (vital) interrupt lines.
721 Only affects "broken" chipsets. Interrupt sharing may be
722 increased on these systems.
725 bool "Machine Check Exception"
726 depends on !X86_VOYAGER
728 Machine Check Exception support allows the processor to notify the
729 kernel if it detects a problem (e.g. overheating, component failure).
730 The action the kernel takes depends on the severity of the problem,
731 ranging from a warning message on the console, to halting the machine.
732 Your processor must be a Pentium or newer to support this - check the
733 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
734 have a design flaw which leads to false MCE events - hence MCE is
735 disabled on all P5 processors, unless explicitly enabled with "mce"
736 as a boot argument. Similarly, if MCE is built in and creates a
737 problem on some new non-standard machine, you can boot with "nomce"
738 to disable it. MCE support simply ignores non-MCE processors like
739 the 386 and 486, so nearly everyone can say Y here.
743 prompt "Intel MCE features"
744 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
746 Additional support for intel specific MCE features such as
751 prompt "AMD MCE features"
752 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
754 Additional support for AMD specific MCE features such as
755 the DRAM Error Threshold.
757 config X86_MCE_NONFATAL
758 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
759 depends on X86_32 && X86_MCE
761 Enabling this feature starts a timer that triggers every 5 seconds which
762 will look at the machine check registers to see if anything happened.
763 Non-fatal problems automatically get corrected (but still logged).
764 Disable this if you don't want to see these messages.
765 Seeing the messages this option prints out may be indicative of dying
766 or out-of-spec (ie, overclocked) hardware.
767 This option only does something on certain CPUs.
768 (AMD Athlon/Duron and Intel Pentium 4)
770 config X86_MCE_P4THERMAL
771 bool "check for P4 thermal throttling interrupt."
772 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
774 Enabling this feature will cause a message to be printed when the P4
775 enters thermal throttling.
778 bool "Enable VM86 support" if EMBEDDED
782 This option is required by programs like DOSEMU to run 16-bit legacy
783 code on X86 processors. It also may be needed by software like
784 XFree86 to initialize some video cards via BIOS. Disabling this
785 option saves about 6k.
788 tristate "Toshiba Laptop support"
791 This adds a driver to safely access the System Management Mode of
792 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
793 not work on models with a Phoenix BIOS. The System Management Mode
794 is used to set the BIOS and power saving options on Toshiba portables.
796 For information on utilities to make use of this driver see the
797 Toshiba Linux utilities web site at:
798 <http://www.buzzard.org.uk/toshiba/>.
800 Say Y if you intend to run this kernel on a Toshiba portable.
804 tristate "Dell laptop support"
806 This adds a driver to safely access the System Management Mode
807 of the CPU on the Dell Inspiron 8000. The System Management Mode
808 is used to read cpu temperature and cooling fan status and to
809 control the fans on the I8K portables.
811 This driver has been tested only on the Inspiron 8000 but it may
812 also work with other Dell laptops. You can force loading on other
813 models by passing the parameter `force=1' to the module. Use at
816 For information on utilities to make use of this driver see the
817 I8K Linux utilities web site at:
818 <http://people.debian.org/~dz/i8k/>
820 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
823 config X86_REBOOTFIXUPS
824 bool "Enable X86 board specific fixups for reboot"
827 This enables chipset and/or board specific fixups to be done
828 in order to get reboot to work correctly. This is only needed on
829 some combinations of hardware and BIOS. The symptom, for which
830 this config is intended, is when reboot ends with a stalled/hung
833 Currently, the only fixup is for the Geode machines using
834 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
836 Say Y if you want to enable the fixup. Currently, it's safe to
837 enable this option even if you don't need it.
841 tristate "/dev/cpu/microcode - microcode support"
844 If you say Y here, you will be able to update the microcode on
845 certain Intel and AMD processors. The Intel support is for the
846 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
847 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
848 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
849 You will obviously need the actual microcode binary data itself
850 which is not shipped with the Linux kernel.
852 This option selects the general module only, you need to select
853 at least one vendor specific module as well.
855 To compile this driver as a module, choose M here: the
856 module will be called microcode.
858 config MICROCODE_INTEL
859 bool "Intel microcode patch loading support"
864 This options enables microcode patch loading support for Intel
867 For latest news and information on obtaining all the required
868 Intel ingredients for this driver, check:
869 <http://www.urbanmyth.org/microcode/>.
872 bool "AMD microcode patch loading support"
876 If you select this option, microcode patch loading support for AMD
877 processors will be enabled.
879 config MICROCODE_OLD_INTERFACE
884 tristate "/dev/cpu/*/msr - Model-specific register support"
886 This device gives privileged processes access to the x86
887 Model-Specific Registers (MSRs). It is a character device with
888 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
889 MSR accesses are directed to a specific CPU on multi-processor
893 tristate "/dev/cpu/*/cpuid - CPU information support"
895 This device gives processes access to the x86 CPUID instruction to
896 be executed on a specific processor. It is a character device
897 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
901 prompt "High Memory Support"
902 default HIGHMEM4G if !X86_NUMAQ
903 default HIGHMEM64G if X86_NUMAQ
908 depends on !X86_NUMAQ
910 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
911 However, the address space of 32-bit x86 processors is only 4
912 Gigabytes large. That means that, if you have a large amount of
913 physical memory, not all of it can be "permanently mapped" by the
914 kernel. The physical memory that's not permanently mapped is called
917 If you are compiling a kernel which will never run on a machine with
918 more than 1 Gigabyte total physical RAM, answer "off" here (default
919 choice and suitable for most users). This will result in a "3GB/1GB"
920 split: 3GB are mapped so that each process sees a 3GB virtual memory
921 space and the remaining part of the 4GB virtual memory space is used
922 by the kernel to permanently map as much physical memory as
925 If the machine has between 1 and 4 Gigabytes physical RAM, then
928 If more than 4 Gigabytes is used then answer "64GB" here. This
929 selection turns Intel PAE (Physical Address Extension) mode on.
930 PAE implements 3-level paging on IA32 processors. PAE is fully
931 supported by Linux, PAE mode is implemented on all recent Intel
932 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
933 then the kernel will not boot on CPUs that don't support PAE!
935 The actual amount of total physical memory will either be
936 auto detected or can be forced by using a kernel command line option
937 such as "mem=256M". (Try "man bootparam" or see the documentation of
938 your boot loader (lilo or loadlin) about how to pass options to the
939 kernel at boot time.)
941 If unsure, say "off".
945 depends on !X86_NUMAQ
947 Select this if you have a 32-bit processor and between 1 and 4
948 gigabytes of physical RAM.
952 depends on !M386 && !M486
955 Select this if you have a 32-bit processor and more than 4
956 gigabytes of physical RAM.
961 depends on EXPERIMENTAL
962 prompt "Memory split" if EMBEDDED
966 Select the desired split between kernel and user memory.
968 If the address range available to the kernel is less than the
969 physical memory installed, the remaining memory will be available
970 as "high memory". Accessing high memory is a little more costly
971 than low memory, as it needs to be mapped into the kernel first.
972 Note that increasing the kernel address space limits the range
973 available to user programs, making the address space there
974 tighter. Selecting anything other than the default 3G/1G split
975 will also likely make your kernel incompatible with binary-only
978 If you are not absolutely sure what you are doing, leave this
982 bool "3G/1G user/kernel split"
983 config VMSPLIT_3G_OPT
985 bool "3G/1G user/kernel split (for full 1G low memory)"
987 bool "2G/2G user/kernel split"
988 config VMSPLIT_2G_OPT
990 bool "2G/2G user/kernel split (for full 2G low memory)"
992 bool "1G/3G user/kernel split"
997 default 0xB0000000 if VMSPLIT_3G_OPT
998 default 0x80000000 if VMSPLIT_2G
999 default 0x78000000 if VMSPLIT_2G_OPT
1000 default 0x40000000 if VMSPLIT_1G
1006 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1009 bool "PAE (Physical Address Extension) Support"
1010 depends on X86_32 && !HIGHMEM4G
1012 PAE is required for NX support, and furthermore enables
1013 larger swapspace support for non-overcommit purposes. It
1014 has the cost of more pagetable lookup overhead, and also
1015 consumes more pagetable space per process.
1017 config ARCH_PHYS_ADDR_T_64BIT
1018 def_bool X86_64 || X86_PAE
1020 config DIRECT_GBPAGES
1021 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1025 Allow the kernel linear mapping to use 1GB pages on CPUs that
1026 support it. This can improve the kernel's performance a tiny bit by
1027 reducing TLB pressure. If in doubt, say "Y".
1029 # Common NUMA Features
1031 bool "Numa Memory Allocation and Scheduler Support"
1033 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1035 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1037 Enable NUMA (Non Uniform Memory Access) support.
1039 The kernel will try to allocate memory used by a CPU on the
1040 local memory controller of the CPU and add some more
1041 NUMA awareness to the kernel.
1043 For 64-bit this is recommended if the system is Intel Core i7
1044 (or later), AMD Opteron, or EM64T NUMA.
1046 For 32-bit this is only needed on (rare) 32-bit-only platforms
1047 that support NUMA topologies, such as NUMAQ / Summit, or if you
1048 boot a 32-bit kernel on a 64-bit NUMA platform.
1050 Otherwise, you should say N.
1052 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1053 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1057 prompt "Old style AMD Opteron NUMA detection"
1058 depends on X86_64 && NUMA && PCI
1060 Enable K8 NUMA node topology detection. You should say Y here if
1061 you have a multi processor AMD K8 system. This uses an old
1062 method to read the NUMA configuration directly from the builtin
1063 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1064 instead, which also takes priority if both are compiled in.
1066 config X86_64_ACPI_NUMA
1068 prompt "ACPI NUMA detection"
1069 depends on X86_64 && NUMA && ACPI && PCI
1072 Enable ACPI SRAT based node topology detection.
1074 # Some NUMA nodes have memory ranges that span
1075 # other nodes. Even though a pfn is valid and
1076 # between a node's start and end pfns, it may not
1077 # reside on that node. See memmap_init_zone()
1079 config NODES_SPAN_OTHER_NODES
1081 depends on X86_64_ACPI_NUMA
1084 bool "NUMA emulation"
1085 depends on X86_64 && NUMA
1087 Enable NUMA emulation. A flat machine will be split
1088 into virtual nodes when booted with "numa=fake=N", where N is the
1089 number of nodes. This is only useful for debugging.
1092 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1094 default "9" if MAXSMP
1095 default "6" if X86_64
1096 default "4" if X86_NUMAQ
1098 depends on NEED_MULTIPLE_NODES
1100 Specify the maximum number of NUMA Nodes available on the target
1101 system. Increases memory reserved to accomodate various tables.
1103 config HAVE_ARCH_BOOTMEM_NODE
1105 depends on X86_32 && NUMA
1107 config ARCH_HAVE_MEMORY_PRESENT
1109 depends on X86_32 && DISCONTIGMEM
1111 config NEED_NODE_MEMMAP_SIZE
1113 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1115 config HAVE_ARCH_ALLOC_REMAP
1117 depends on X86_32 && NUMA
1119 config ARCH_FLATMEM_ENABLE
1121 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1123 config ARCH_DISCONTIGMEM_ENABLE
1125 depends on NUMA && X86_32
1127 config ARCH_DISCONTIGMEM_DEFAULT
1129 depends on NUMA && X86_32
1131 config ARCH_SPARSEMEM_DEFAULT
1135 config ARCH_SPARSEMEM_ENABLE
1137 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1138 select SPARSEMEM_STATIC if X86_32
1139 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1141 config ARCH_SELECT_MEMORY_MODEL
1143 depends on ARCH_SPARSEMEM_ENABLE
1145 config ARCH_MEMORY_PROBE
1147 depends on MEMORY_HOTPLUG
1152 bool "Allocate 3rd-level pagetables from highmem"
1153 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1155 The VM uses one page table entry for each page of physical memory.
1156 For systems with a lot of RAM, this can be wasteful of precious
1157 low memory. Setting this option will put user-space page table
1158 entries in high memory.
1160 config X86_CHECK_BIOS_CORRUPTION
1161 bool "Check for low memory corruption"
1163 Periodically check for memory corruption in low memory, which
1164 is suspected to be caused by BIOS. Even when enabled in the
1165 configuration, it is disabled at runtime. Enable it by
1166 setting "memory_corruption_check=1" on the kernel command
1167 line. By default it scans the low 64k of memory every 60
1168 seconds; see the memory_corruption_check_size and
1169 memory_corruption_check_period parameters in
1170 Documentation/kernel-parameters.txt to adjust this.
1172 When enabled with the default parameters, this option has
1173 almost no overhead, as it reserves a relatively small amount
1174 of memory and scans it infrequently. It both detects corruption
1175 and prevents it from affecting the running system.
1177 It is, however, intended as a diagnostic tool; if repeatable
1178 BIOS-originated corruption always affects the same memory,
1179 you can use memmap= to prevent the kernel from using that
1182 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1183 bool "Set the default setting of memory_corruption_check"
1184 depends on X86_CHECK_BIOS_CORRUPTION
1187 Set whether the default state of memory_corruption_check is
1190 config X86_RESERVE_LOW_64K
1191 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1194 Reserve the first 64K of physical RAM on BIOSes that are known
1195 to potentially corrupt that memory range. A numbers of BIOSes are
1196 known to utilize this area during suspend/resume, so it must not
1197 be used by the kernel.
1199 Set this to N if you are absolutely sure that you trust the BIOS
1200 to get all its memory reservations and usages right.
1202 If you have doubts about the BIOS (e.g. suspend/resume does not
1203 work or there's kernel crashes after certain hardware hotplug
1204 events) and it's not AMI or Phoenix, then you might want to enable
1205 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1206 corruption patterns.
1210 config MATH_EMULATION
1212 prompt "Math emulation" if X86_32
1214 Linux can emulate a math coprocessor (used for floating point
1215 operations) if you don't have one. 486DX and Pentium processors have
1216 a math coprocessor built in, 486SX and 386 do not, unless you added
1217 a 487DX or 387, respectively. (The messages during boot time can
1218 give you some hints here ["man dmesg"].) Everyone needs either a
1219 coprocessor or this emulation.
1221 If you don't have a math coprocessor, you need to say Y here; if you
1222 say Y here even though you have a coprocessor, the coprocessor will
1223 be used nevertheless. (This behavior can be changed with the kernel
1224 command line option "no387", which comes handy if your coprocessor
1225 is broken. Try "man bootparam" or see the documentation of your boot
1226 loader (lilo or loadlin) about how to pass options to the kernel at
1227 boot time.) This means that it is a good idea to say Y here if you
1228 intend to use this kernel on different machines.
1230 More information about the internals of the Linux math coprocessor
1231 emulation can be found in <file:arch/x86/math-emu/README>.
1233 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1234 kernel, it won't hurt.
1237 bool "MTRR (Memory Type Range Register) support"
1239 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1240 the Memory Type Range Registers (MTRRs) may be used to control
1241 processor access to memory ranges. This is most useful if you have
1242 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1243 allows bus write transfers to be combined into a larger transfer
1244 before bursting over the PCI/AGP bus. This can increase performance
1245 of image write operations 2.5 times or more. Saying Y here creates a
1246 /proc/mtrr file which may be used to manipulate your processor's
1247 MTRRs. Typically the X server should use this.
1249 This code has a reasonably generic interface so that similar
1250 control registers on other processors can be easily supported
1253 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1254 Registers (ARRs) which provide a similar functionality to MTRRs. For
1255 these, the ARRs are used to emulate the MTRRs.
1256 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1257 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1258 write-combining. All of these processors are supported by this code
1259 and it makes sense to say Y here if you have one of them.
1261 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1262 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1263 can lead to all sorts of problems, so it's good to say Y here.
1265 You can safely say Y even if your machine doesn't have MTRRs, you'll
1266 just add about 9 KB to your kernel.
1268 See <file:Documentation/x86/mtrr.txt> for more information.
1270 config MTRR_SANITIZER
1272 prompt "MTRR cleanup support"
1275 Convert MTRR layout from continuous to discrete, so X drivers can
1276 add writeback entries.
1278 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1279 The largest mtrr entry size for a continous block can be set with
1284 config MTRR_SANITIZER_ENABLE_DEFAULT
1285 int "MTRR cleanup enable value (0-1)"
1288 depends on MTRR_SANITIZER
1290 Enable mtrr cleanup default value
1292 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1293 int "MTRR cleanup spare reg num (0-7)"
1296 depends on MTRR_SANITIZER
1298 mtrr cleanup spare entries default, it can be changed via
1299 mtrr_spare_reg_nr=N on the kernel command line.
1303 prompt "x86 PAT support"
1306 Use PAT attributes to setup page level cache control.
1308 PATs are the modern equivalents of MTRRs and are much more
1309 flexible than MTRRs.
1311 Say N here if you see bootup problems (boot crash, boot hang,
1312 spontaneous reboots) or a non-working video driver.
1317 bool "EFI runtime service support"
1320 This enables the kernel to use EFI runtime services that are
1321 available (such as the EFI variable services).
1323 This option is only useful on systems that have EFI firmware.
1324 In addition, you should use the latest ELILO loader available
1325 at <http://elilo.sourceforge.net> in order to take advantage
1326 of EFI runtime services. However, even with this option, the
1327 resultant kernel should continue to boot on existing non-EFI
1332 prompt "Enable seccomp to safely compute untrusted bytecode"
1334 This kernel feature is useful for number crunching applications
1335 that may need to compute untrusted bytecode during their
1336 execution. By using pipes or other transports made available to
1337 the process as file descriptors supporting the read/write
1338 syscalls, it's possible to isolate those applications in
1339 their own address space using seccomp. Once seccomp is
1340 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1341 and the task is only allowed to execute a few safe syscalls
1342 defined by each seccomp mode.
1344 If unsure, say Y. Only embedded should say N here.
1346 config CC_STACKPROTECTOR
1347 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1348 depends on X86_64 && EXPERIMENTAL && BROKEN
1350 This option turns on the -fstack-protector GCC feature. This
1351 feature puts, at the beginning of critical functions, a canary
1352 value on the stack just before the return address, and validates
1353 the value just before actually returning. Stack based buffer
1354 overflows (that need to overwrite this return address) now also
1355 overwrite the canary, which gets detected and the attack is then
1356 neutralized via a kernel panic.
1358 This feature requires gcc version 4.2 or above, or a distribution
1359 gcc with the feature backported. Older versions are automatically
1360 detected and for those versions, this configuration option is ignored.
1362 config CC_STACKPROTECTOR_ALL
1363 bool "Use stack-protector for all functions"
1364 depends on CC_STACKPROTECTOR
1366 Normally, GCC only inserts the canary value protection for
1367 functions that use large-ish on-stack buffers. By enabling
1368 this option, GCC will be asked to do this for ALL functions.
1370 source kernel/Kconfig.hz
1373 bool "kexec system call"
1374 depends on X86_BIOS_REBOOT
1376 kexec is a system call that implements the ability to shutdown your
1377 current kernel, and to start another kernel. It is like a reboot
1378 but it is independent of the system firmware. And like a reboot
1379 you can start any kernel with it, not just Linux.
1381 The name comes from the similarity to the exec system call.
1383 It is an ongoing process to be certain the hardware in a machine
1384 is properly shutdown, so do not be surprised if this code does not
1385 initially work for you. It may help to enable device hotplugging
1386 support. As of this writing the exact hardware interface is
1387 strongly in flux, so no good recommendation can be made.
1390 bool "kernel crash dumps"
1391 depends on X86_64 || (X86_32 && HIGHMEM)
1393 Generate crash dump after being started by kexec.
1394 This should be normally only set in special crash dump kernels
1395 which are loaded in the main kernel with kexec-tools into
1396 a specially reserved region and then later executed after
1397 a crash by kdump/kexec. The crash dump kernel must be compiled
1398 to a memory address not used by the main kernel or BIOS using
1399 PHYSICAL_START, or it must be built as a relocatable image
1400 (CONFIG_RELOCATABLE=y).
1401 For more details see Documentation/kdump/kdump.txt
1404 bool "kexec jump (EXPERIMENTAL)"
1405 depends on EXPERIMENTAL
1406 depends on KEXEC && HIBERNATION && X86_32
1408 Jump between original kernel and kexeced kernel and invoke
1409 code in physical address mode via KEXEC
1411 config PHYSICAL_START
1412 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1413 default "0x1000000" if X86_NUMAQ
1414 default "0x200000" if X86_64
1417 This gives the physical address where the kernel is loaded.
1419 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1420 bzImage will decompress itself to above physical address and
1421 run from there. Otherwise, bzImage will run from the address where
1422 it has been loaded by the boot loader and will ignore above physical
1425 In normal kdump cases one does not have to set/change this option
1426 as now bzImage can be compiled as a completely relocatable image
1427 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1428 address. This option is mainly useful for the folks who don't want
1429 to use a bzImage for capturing the crash dump and want to use a
1430 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1431 to be specifically compiled to run from a specific memory area
1432 (normally a reserved region) and this option comes handy.
1434 So if you are using bzImage for capturing the crash dump, leave
1435 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1436 Otherwise if you plan to use vmlinux for capturing the crash dump
1437 change this value to start of the reserved region (Typically 16MB
1438 0x1000000). In other words, it can be set based on the "X" value as
1439 specified in the "crashkernel=YM@XM" command line boot parameter
1440 passed to the panic-ed kernel. Typically this parameter is set as
1441 crashkernel=64M@16M. Please take a look at
1442 Documentation/kdump/kdump.txt for more details about crash dumps.
1444 Usage of bzImage for capturing the crash dump is recommended as
1445 one does not have to build two kernels. Same kernel can be used
1446 as production kernel and capture kernel. Above option should have
1447 gone away after relocatable bzImage support is introduced. But it
1448 is present because there are users out there who continue to use
1449 vmlinux for dump capture. This option should go away down the
1452 Don't change this unless you know what you are doing.
1455 bool "Build a relocatable kernel (EXPERIMENTAL)"
1456 depends on EXPERIMENTAL
1458 This builds a kernel image that retains relocation information
1459 so it can be loaded someplace besides the default 1MB.
1460 The relocations tend to make the kernel binary about 10% larger,
1461 but are discarded at runtime.
1463 One use is for the kexec on panic case where the recovery kernel
1464 must live at a different physical address than the primary
1467 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1468 it has been loaded at and the compile time physical address
1469 (CONFIG_PHYSICAL_START) is ignored.
1471 config PHYSICAL_ALIGN
1473 prompt "Alignment value to which kernel should be aligned" if X86_32
1474 default "0x100000" if X86_32
1475 default "0x200000" if X86_64
1476 range 0x2000 0x400000
1478 This value puts the alignment restrictions on physical address
1479 where kernel is loaded and run from. Kernel is compiled for an
1480 address which meets above alignment restriction.
1482 If bootloader loads the kernel at a non-aligned address and
1483 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1484 address aligned to above value and run from there.
1486 If bootloader loads the kernel at a non-aligned address and
1487 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1488 load address and decompress itself to the address it has been
1489 compiled for and run from there. The address for which kernel is
1490 compiled already meets above alignment restrictions. Hence the
1491 end result is that kernel runs from a physical address meeting
1492 above alignment restrictions.
1494 Don't change this unless you know what you are doing.
1497 bool "Support for hot-pluggable CPUs"
1498 depends on SMP && HOTPLUG && !X86_VOYAGER
1500 Say Y here to allow turning CPUs off and on. CPUs can be
1501 controlled through /sys/devices/system/cpu.
1502 ( Note: power management support will enable this option
1503 automatically on SMP systems. )
1504 Say N if you want to disable CPU hotplug.
1508 prompt "Compat VDSO support"
1509 depends on X86_32 || IA32_EMULATION
1511 Map the 32-bit VDSO to the predictable old-style address too.
1513 Say N here if you are running a sufficiently recent glibc
1514 version (2.3.3 or later), to remove the high-mapped
1515 VDSO mapping and to exclusively use the randomized VDSO.
1520 bool "Built-in kernel command line"
1523 Allow for specifying boot arguments to the kernel at
1524 build time. On some systems (e.g. embedded ones), it is
1525 necessary or convenient to provide some or all of the
1526 kernel boot arguments with the kernel itself (that is,
1527 to not rely on the boot loader to provide them.)
1529 To compile command line arguments into the kernel,
1530 set this option to 'Y', then fill in the
1531 the boot arguments in CONFIG_CMDLINE.
1533 Systems with fully functional boot loaders (i.e. non-embedded)
1534 should leave this option set to 'N'.
1537 string "Built-in kernel command string"
1538 depends on CMDLINE_BOOL
1541 Enter arguments here that should be compiled into the kernel
1542 image and used at boot time. If the boot loader provides a
1543 command line at boot time, it is appended to this string to
1544 form the full kernel command line, when the system boots.
1546 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1547 change this behavior.
1549 In most cases, the command line (whether built-in or provided
1550 by the boot loader) should specify the device for the root
1553 config CMDLINE_OVERRIDE
1554 bool "Built-in command line overrides boot loader arguments"
1556 depends on CMDLINE_BOOL
1558 Set this option to 'Y' to have the kernel ignore the boot loader
1559 command line, and use ONLY the built-in command line.
1561 This is used to work around broken boot loaders. This should
1562 be set to 'N' under normal conditions.
1566 config ARCH_ENABLE_MEMORY_HOTPLUG
1568 depends on X86_64 || (X86_32 && HIGHMEM)
1570 config ARCH_ENABLE_MEMORY_HOTREMOVE
1572 depends on MEMORY_HOTPLUG
1574 config HAVE_ARCH_EARLY_PFN_TO_NID
1578 menu "Power management and ACPI options"
1579 depends on !X86_VOYAGER
1581 config ARCH_HIBERNATION_HEADER
1583 depends on X86_64 && HIBERNATION
1585 source "kernel/power/Kconfig"
1587 source "drivers/acpi/Kconfig"
1592 depends on APM || APM_MODULE
1595 tristate "APM (Advanced Power Management) BIOS support"
1596 depends on X86_32 && PM_SLEEP
1598 APM is a BIOS specification for saving power using several different
1599 techniques. This is mostly useful for battery powered laptops with
1600 APM compliant BIOSes. If you say Y here, the system time will be
1601 reset after a RESUME operation, the /proc/apm device will provide
1602 battery status information, and user-space programs will receive
1603 notification of APM "events" (e.g. battery status change).
1605 If you select "Y" here, you can disable actual use of the APM
1606 BIOS by passing the "apm=off" option to the kernel at boot time.
1608 Note that the APM support is almost completely disabled for
1609 machines with more than one CPU.
1611 In order to use APM, you will need supporting software. For location
1612 and more information, read <file:Documentation/power/pm.txt> and the
1613 Battery Powered Linux mini-HOWTO, available from
1614 <http://www.tldp.org/docs.html#howto>.
1616 This driver does not spin down disk drives (see the hdparm(8)
1617 manpage ("man 8 hdparm") for that), and it doesn't turn off
1618 VESA-compliant "green" monitors.
1620 This driver does not support the TI 4000M TravelMate and the ACER
1621 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1622 desktop machines also don't have compliant BIOSes, and this driver
1623 may cause those machines to panic during the boot phase.
1625 Generally, if you don't have a battery in your machine, there isn't
1626 much point in using this driver and you should say N. If you get
1627 random kernel OOPSes or reboots that don't seem to be related to
1628 anything, try disabling/enabling this option (or disabling/enabling
1631 Some other things you should try when experiencing seemingly random,
1634 1) make sure that you have enough swap space and that it is
1636 2) pass the "no-hlt" option to the kernel
1637 3) switch on floating point emulation in the kernel and pass
1638 the "no387" option to the kernel
1639 4) pass the "floppy=nodma" option to the kernel
1640 5) pass the "mem=4M" option to the kernel (thereby disabling
1641 all but the first 4 MB of RAM)
1642 6) make sure that the CPU is not over clocked.
1643 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1644 8) disable the cache from your BIOS settings
1645 9) install a fan for the video card or exchange video RAM
1646 10) install a better fan for the CPU
1647 11) exchange RAM chips
1648 12) exchange the motherboard.
1650 To compile this driver as a module, choose M here: the
1651 module will be called apm.
1655 config APM_IGNORE_USER_SUSPEND
1656 bool "Ignore USER SUSPEND"
1658 This option will ignore USER SUSPEND requests. On machines with a
1659 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1660 series notebooks, it is necessary to say Y because of a BIOS bug.
1662 config APM_DO_ENABLE
1663 bool "Enable PM at boot time"
1665 Enable APM features at boot time. From page 36 of the APM BIOS
1666 specification: "When disabled, the APM BIOS does not automatically
1667 power manage devices, enter the Standby State, enter the Suspend
1668 State, or take power saving steps in response to CPU Idle calls."
1669 This driver will make CPU Idle calls when Linux is idle (unless this
1670 feature is turned off -- see "Do CPU IDLE calls", below). This
1671 should always save battery power, but more complicated APM features
1672 will be dependent on your BIOS implementation. You may need to turn
1673 this option off if your computer hangs at boot time when using APM
1674 support, or if it beeps continuously instead of suspending. Turn
1675 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1676 T400CDT. This is off by default since most machines do fine without
1680 bool "Make CPU Idle calls when idle"
1682 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1683 On some machines, this can activate improved power savings, such as
1684 a slowed CPU clock rate, when the machine is idle. These idle calls
1685 are made after the idle loop has run for some length of time (e.g.,
1686 333 mS). On some machines, this will cause a hang at boot time or
1687 whenever the CPU becomes idle. (On machines with more than one CPU,
1688 this option does nothing.)
1690 config APM_DISPLAY_BLANK
1691 bool "Enable console blanking using APM"
1693 Enable console blanking using the APM. Some laptops can use this to
1694 turn off the LCD backlight when the screen blanker of the Linux
1695 virtual console blanks the screen. Note that this is only used by
1696 the virtual console screen blanker, and won't turn off the backlight
1697 when using the X Window system. This also doesn't have anything to
1698 do with your VESA-compliant power-saving monitor. Further, this
1699 option doesn't work for all laptops -- it might not turn off your
1700 backlight at all, or it might print a lot of errors to the console,
1701 especially if you are using gpm.
1703 config APM_ALLOW_INTS
1704 bool "Allow interrupts during APM BIOS calls"
1706 Normally we disable external interrupts while we are making calls to
1707 the APM BIOS as a measure to lessen the effects of a badly behaving
1708 BIOS implementation. The BIOS should reenable interrupts if it
1709 needs to. Unfortunately, some BIOSes do not -- especially those in
1710 many of the newer IBM Thinkpads. If you experience hangs when you
1711 suspend, try setting this to Y. Otherwise, say N.
1715 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1717 source "drivers/cpuidle/Kconfig"
1719 source "drivers/idle/Kconfig"
1724 menu "Bus options (PCI etc.)"
1729 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1731 Find out whether you have a PCI motherboard. PCI is the name of a
1732 bus system, i.e. the way the CPU talks to the other stuff inside
1733 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1734 VESA. If you have PCI, say Y, otherwise N.
1737 prompt "PCI access mode"
1738 depends on X86_32 && PCI
1741 On PCI systems, the BIOS can be used to detect the PCI devices and
1742 determine their configuration. However, some old PCI motherboards
1743 have BIOS bugs and may crash if this is done. Also, some embedded
1744 PCI-based systems don't have any BIOS at all. Linux can also try to
1745 detect the PCI hardware directly without using the BIOS.
1747 With this option, you can specify how Linux should detect the
1748 PCI devices. If you choose "BIOS", the BIOS will be used,
1749 if you choose "Direct", the BIOS won't be used, and if you
1750 choose "MMConfig", then PCI Express MMCONFIG will be used.
1751 If you choose "Any", the kernel will try MMCONFIG, then the
1752 direct access method and falls back to the BIOS if that doesn't
1753 work. If unsure, go with the default, which is "Any".
1758 config PCI_GOMMCONFIG
1775 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1777 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1780 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1784 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1788 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1795 bool "Support mmconfig PCI config space access"
1796 depends on X86_64 && PCI && ACPI
1799 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1800 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1802 DMA remapping (DMAR) devices support enables independent address
1803 translations for Direct Memory Access (DMA) from devices.
1804 These DMA remapping devices are reported via ACPI tables
1805 and include PCI device scope covered by these DMA
1808 config DMAR_DEFAULT_ON
1810 prompt "Enable DMA Remapping Devices by default"
1813 Selecting this option will enable a DMAR device at boot time if
1814 one is found. If this option is not selected, DMAR support can
1815 be enabled by passing intel_iommu=on to the kernel. It is
1816 recommended you say N here while the DMAR code remains
1821 prompt "Support for Graphics workaround"
1824 Current Graphics drivers tend to use physical address
1825 for DMA and avoid using DMA APIs. Setting this config
1826 option permits the IOMMU driver to set a unity map for
1827 all the OS-visible memory. Hence the driver can continue
1828 to use physical addresses for DMA.
1830 config DMAR_FLOPPY_WA
1834 Floppy disk drivers are know to bypass DMA API calls
1835 thereby failing to work when IOMMU is enabled. This
1836 workaround will setup a 1:1 mapping for the first
1837 16M to make floppy (an ISA device) work.
1840 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1841 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1843 Supports Interrupt remapping for IO-APIC and MSI devices.
1844 To use x2apic mode in the CPU's which support x2APIC enhancements or
1845 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1847 source "drivers/pci/pcie/Kconfig"
1849 source "drivers/pci/Kconfig"
1851 # x86_64 have no ISA slots, but do have ISA-style DMA.
1859 depends on !X86_VOYAGER
1861 Find out whether you have ISA slots on your motherboard. ISA is the
1862 name of a bus system, i.e. the way the CPU talks to the other stuff
1863 inside your box. Other bus systems are PCI, EISA, MicroChannel
1864 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1865 newer boards don't support it. If you have ISA, say Y, otherwise N.
1871 The Extended Industry Standard Architecture (EISA) bus was
1872 developed as an open alternative to the IBM MicroChannel bus.
1874 The EISA bus provided some of the features of the IBM MicroChannel
1875 bus while maintaining backward compatibility with cards made for
1876 the older ISA bus. The EISA bus saw limited use between 1988 and
1877 1995 when it was made obsolete by the PCI bus.
1879 Say Y here if you are building a kernel for an EISA-based machine.
1883 source "drivers/eisa/Kconfig"
1886 bool "MCA support" if !X86_VOYAGER
1887 default y if X86_VOYAGER
1889 MicroChannel Architecture is found in some IBM PS/2 machines and
1890 laptops. It is a bus system similar to PCI or ISA. See
1891 <file:Documentation/mca.txt> (and especially the web page given
1892 there) before attempting to build an MCA bus kernel.
1894 source "drivers/mca/Kconfig"
1897 tristate "NatSemi SCx200 support"
1898 depends on !X86_VOYAGER
1900 This provides basic support for National Semiconductor's
1901 (now AMD's) Geode processors. The driver probes for the
1902 PCI-IDs of several on-chip devices, so its a good dependency
1903 for other scx200_* drivers.
1905 If compiled as a module, the driver is named scx200.
1907 config SCx200HR_TIMER
1908 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1909 depends on SCx200 && GENERIC_TIME
1912 This driver provides a clocksource built upon the on-chip
1913 27MHz high-resolution timer. Its also a workaround for
1914 NSC Geode SC-1100's buggy TSC, which loses time when the
1915 processor goes idle (as is done by the scheduler). The
1916 other workaround is idle=poll boot option.
1918 config GEODE_MFGPT_TIMER
1920 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1921 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1923 This driver provides a clock event source based on the MFGPT
1924 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1925 MFGPTs have a better resolution and max interval than the
1926 generic PIT, and are suitable for use as high-res timers.
1929 bool "One Laptop Per Child support"
1932 Add support for detecting the unique features of the OLPC
1939 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1941 source "drivers/pcmcia/Kconfig"
1943 source "drivers/pci/hotplug/Kconfig"
1948 menu "Executable file formats / Emulations"
1950 source "fs/Kconfig.binfmt"
1952 config IA32_EMULATION
1953 bool "IA32 Emulation"
1955 select COMPAT_BINFMT_ELF
1957 Include code to run 32-bit programs under a 64-bit kernel. You should
1958 likely turn this on, unless you're 100% sure that you don't have any
1959 32-bit programs left.
1962 tristate "IA32 a.out support"
1963 depends on IA32_EMULATION
1965 Support old a.out binaries in the 32bit emulation.
1969 depends on IA32_EMULATION
1971 config COMPAT_FOR_U64_ALIGNMENT
1975 config SYSVIPC_COMPAT
1977 depends on COMPAT && SYSVIPC
1982 config HAVE_ATOMIC_IOMAP
1986 source "net/Kconfig"
1988 source "drivers/Kconfig"
1990 source "drivers/firmware/Kconfig"
1994 source "arch/x86/Kconfig.debug"
1996 source "security/Kconfig"
1998 source "crypto/Kconfig"
2000 source "arch/x86/kvm/Kconfig"
2002 source "lib/Kconfig"
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