2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
144 config ARCH_SUSPEND_POSSIBLE
151 config ARCH_POPULATES_NODE_MAP
158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
161 # Use the generic interrupt handling code in kernel/irq/:
162 config GENERIC_HARDIRQS
166 config GENERIC_IRQ_PROBE
170 config GENERIC_PENDING_IRQ
172 depends on GENERIC_HARDIRQS && SMP
175 config USE_GENERIC_SMP_HELPERS
181 depends on X86_32 && SMP
185 depends on X86_64 && SMP
192 config X86_TRAMPOLINE
194 depends on SMP || (64BIT && ACPI_SLEEP)
197 config X86_32_LAZY_GS
199 depends on X86_32 && !CC_STACKPROTECTOR
203 source "init/Kconfig"
204 source "kernel/Kconfig.freezer"
206 menu "Processor type and features"
208 source "kernel/time/Kconfig"
211 bool "Symmetric multi-processing support"
213 This enables support for systems with more than one CPU. If you have
214 a system with only one CPU, like most personal computers, say N. If
215 you have a system with more than one CPU, say Y.
217 If you say N here, the kernel will run on single and multiprocessor
218 machines, but will use only one CPU of a multiprocessor machine. If
219 you say Y here, the kernel will run on many, but not all,
220 singleprocessor machines. On a singleprocessor machine, the kernel
221 will run faster if you say N here.
223 Note that if you say Y here and choose architecture "586" or
224 "Pentium" under "Processor family", the kernel will not work on 486
225 architectures. Similarly, multiprocessor kernels for the "PPro"
226 architecture may not work on all Pentium based boards.
228 People using multiprocessor machines who say Y here should also say
229 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
230 Management" code will be disabled if you say Y here.
232 See also <file:Documentation/i386/IO-APIC.txt>,
233 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
234 <http://www.tldp.org/docs.html#howto>.
236 If you don't know what to do here, say N.
239 bool "Support x2apic"
240 depends on X86_LOCAL_APIC && X86_64
242 This enables x2apic support on CPUs that have this feature.
244 This allows 32-bit apic IDs (so it can support very large systems),
245 and accesses the local apic via MSRs not via mmio.
247 ( On certain CPU models you may need to enable INTR_REMAP too,
248 to get functional x2apic mode. )
250 If you don't know what to do here, say N.
253 bool "Support sparse irq numbering"
254 depends on PCI_MSI || HT_IRQ
256 This enables support for sparse irqs. This is useful for distro
257 kernels that want to define a high CONFIG_NR_CPUS value but still
258 want to have low kernel memory footprint on smaller machines.
260 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
261 out the irq_desc[] array in a more NUMA-friendly way. )
263 If you don't know what to do here, say N.
265 config NUMA_MIGRATE_IRQ_DESC
266 bool "Move irq desc when changing irq smp_affinity"
267 depends on SPARSE_IRQ && NUMA
270 This enables moving irq_desc to cpu/node that irq will use handled.
272 If you don't know what to do here, say N.
275 bool "Enable MPS table" if ACPI
277 depends on X86_LOCAL_APIC
279 For old smp systems that do not have proper acpi support. Newer systems
280 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
283 bool "Support for big SMP systems with more than 8 CPUs"
284 depends on X86_32 && SMP
286 This option is needed for the systems that have more than 8 CPUs
289 config X86_EXTENDED_PLATFORM
290 bool "Support for extended (non-PC) x86 platforms"
293 If you disable this option then the kernel will only support
294 standard PC platforms. (which covers the vast majority of
297 If you enable this option then you'll be able to select support
298 for the following (non-PC) 32 bit x86 platforms:
302 SGI 320/540 (Visual Workstation)
303 Summit/EXA (IBM x440)
304 Unisys ES7000 IA32 series
306 If you have one of these systems, or if you want to build a
307 generic distribution kernel, say Y here - otherwise say N.
311 config X86_EXTENDED_PLATFORM
312 bool "Support for extended (non-PC) x86 platforms"
315 If you disable this option then the kernel will only support
316 standard PC platforms. (which covers the vast majority of
319 If you enable this option then you'll be able to select support
320 for the following (non-PC) 64 bit x86 platforms:
324 If you have one of these systems, or if you want to build a
325 generic distribution kernel, say Y here - otherwise say N.
327 # This is an alphabetically sorted list of 64 bit extended platforms
328 # Please maintain the alphabetic order if and when there are additions
333 depends on X86_64 && PCI
334 depends on X86_EXTENDED_PLATFORM
336 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
337 supposed to run on these EM64T-based machines. Only choose this option
338 if you have one of these machines.
341 bool "SGI Ultraviolet"
343 depends on X86_EXTENDED_PLATFORM
346 This option is needed in order to support SGI Ultraviolet systems.
347 If you don't have one of these, you should say N here.
349 # Following is an alphabetically sorted list of 32 bit extended platforms
350 # Please maintain the alphabetic order if and when there are additions
355 depends on X86_EXTENDED_PLATFORM
357 Select this for an AMD Elan processor.
359 Do not use this option for K6/Athlon/Opteron processors!
361 If unsure, choose "PC-compatible" instead.
364 bool "RDC R-321x SoC"
366 depends on X86_EXTENDED_PLATFORM
368 select X86_REBOOTFIXUPS
370 This option is needed for RDC R-321x system-on-chip, also known
372 If you don't have one of these chips, you should say N here.
374 config X86_32_NON_STANDARD
375 bool "Support non-standard 32-bit SMP architectures"
376 depends on X86_32 && SMP
377 depends on X86_EXTENDED_PLATFORM
379 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
380 subarchitectures. It is intended for a generic binary kernel.
381 if you select them all, kernel will probe it one by one. and will
384 # Alphabetically sorted list of Non standard 32 bit platforms
387 bool "NUMAQ (IBM/Sequent)"
388 depends on X86_32_NON_STANDARD
392 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
393 NUMA multiquad box. This changes the way that processors are
394 bootstrapped, and uses Clustered Logical APIC addressing mode instead
395 of Flat Logical. You will need a new lynxer.elf file to flash your
396 firmware with - send email to <Martin.Bligh@us.ibm.com>.
399 bool "SGI 320/540 (Visual Workstation)"
400 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
401 depends on X86_32_NON_STANDARD
403 The SGI Visual Workstation series is an IA32-based workstation
404 based on SGI systems chips with some legacy PC hardware attached.
406 Say Y here to create a kernel to run on the SGI 320 or 540.
408 A kernel compiled for the Visual Workstation will run on general
409 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
412 bool "Summit/EXA (IBM x440)"
413 depends on X86_32_NON_STANDARD
415 This option is needed for IBM systems that use the Summit/EXA chipset.
416 In particular, it is needed for the x440.
419 bool "Unisys ES7000 IA32 series"
420 depends on X86_32_NON_STANDARD && X86_BIGSMP
422 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
423 supposed to run on an IA32-based Unisys ES7000 system.
425 config SCHED_OMIT_FRAME_POINTER
427 prompt "Single-depth WCHAN output"
430 Calculate simpler /proc/<PID>/wchan values. If this option
431 is disabled then wchan values will recurse back to the
432 caller function. This provides more accurate wchan values,
433 at the expense of slightly more scheduling overhead.
435 If in doubt, say "Y".
437 menuconfig PARAVIRT_GUEST
438 bool "Paravirtualized guest support"
440 Say Y here to get to see options related to running Linux under
441 various hypervisors. This option alone does not add any kernel code.
443 If you say N, all options in this submenu will be skipped and disabled.
447 source "arch/x86/xen/Kconfig"
450 bool "VMI Guest support"
454 VMI provides a paravirtualized interface to the VMware ESX server
455 (it could be used by other hypervisors in theory too, but is not
456 at the moment), by linking the kernel to a GPL-ed ROM module
457 provided by the hypervisor.
460 bool "KVM paravirtualized clock"
462 select PARAVIRT_CLOCK
464 Turning on this option will allow you to run a paravirtualized clock
465 when running over the KVM hypervisor. Instead of relying on a PIT
466 (or probably other) emulation by the underlying device model, the host
467 provides the guest with timing infrastructure such as time of day, and
471 bool "KVM Guest support"
474 This option enables various optimizations for running under the KVM
477 source "arch/x86/lguest/Kconfig"
480 bool "Enable paravirtualization code"
482 This changes the kernel so it can modify itself when it is run
483 under a hypervisor, potentially improving performance significantly
484 over full virtualization. However, when run without a hypervisor
485 the kernel is theoretically slower and slightly larger.
487 config PARAVIRT_CLOCK
493 config PARAVIRT_DEBUG
494 bool "paravirt-ops debugging"
495 depends on PARAVIRT && DEBUG_KERNEL
497 Enable to debug paravirt_ops internals. Specifically, BUG if
498 a paravirt_op is missing when it is called.
503 This option adds a kernel parameter 'memtest', which allows memtest
505 memtest=0, mean disabled; -- default
506 memtest=1, mean do 1 test pattern;
508 memtest=4, mean do 4 test patterns.
509 If you are unsure how to answer this question, answer N.
511 config X86_SUMMIT_NUMA
513 depends on X86_32 && NUMA && X86_32_NON_STANDARD
515 config X86_CYCLONE_TIMER
517 depends on X86_32_NON_STANDARD
519 source "arch/x86/Kconfig.cpu"
523 prompt "HPET Timer Support" if X86_32
525 Use the IA-PC HPET (High Precision Event Timer) to manage
526 time in preference to the PIT and RTC, if a HPET is
528 HPET is the next generation timer replacing legacy 8254s.
529 The HPET provides a stable time base on SMP
530 systems, unlike the TSC, but it is more expensive to access,
531 as it is off-chip. You can find the HPET spec at
532 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
534 You can safely choose Y here. However, HPET will only be
535 activated if the platform and the BIOS support this feature.
536 Otherwise the 8254 will be used for timing services.
538 Choose N to continue using the legacy 8254 timer.
540 config HPET_EMULATE_RTC
542 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
544 # Mark as embedded because too many people got it wrong.
545 # The code disables itself when not needed.
548 bool "Enable DMI scanning" if EMBEDDED
550 Enabled scanning of DMI to identify machine quirks. Say Y
551 here unless you have verified that your setup is not
552 affected by entries in the DMI blacklist. Required by PNP
556 bool "GART IOMMU support" if EMBEDDED
560 depends on X86_64 && PCI
562 Support for full DMA access of devices with 32bit memory access only
563 on systems with more than 3GB. This is usually needed for USB,
564 sound, many IDE/SATA chipsets and some other devices.
565 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
566 based hardware IOMMU and a software bounce buffer based IOMMU used
567 on Intel systems and as fallback.
568 The code is only active when needed (enough memory and limited
569 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
573 bool "IBM Calgary IOMMU support"
575 depends on X86_64 && PCI && EXPERIMENTAL
577 Support for hardware IOMMUs in IBM's xSeries x366 and x460
578 systems. Needed to run systems with more than 3GB of memory
579 properly with 32-bit PCI devices that do not support DAC
580 (Double Address Cycle). Calgary also supports bus level
581 isolation, where all DMAs pass through the IOMMU. This
582 prevents them from going anywhere except their intended
583 destination. This catches hard-to-find kernel bugs and
584 mis-behaving drivers and devices that do not use the DMA-API
585 properly to set up their DMA buffers. The IOMMU can be
586 turned off at boot time with the iommu=off parameter.
587 Normally the kernel will make the right choice by itself.
590 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
592 prompt "Should Calgary be enabled by default?"
593 depends on CALGARY_IOMMU
595 Should Calgary be enabled by default? if you choose 'y', Calgary
596 will be used (if it exists). If you choose 'n', Calgary will not be
597 used even if it exists. If you choose 'n' and would like to use
598 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
602 bool "AMD IOMMU support"
605 depends on X86_64 && PCI && ACPI
607 With this option you can enable support for AMD IOMMU hardware in
608 your system. An IOMMU is a hardware component which provides
609 remapping of DMA memory accesses from devices. With an AMD IOMMU you
610 can isolate the the DMA memory of different devices and protect the
611 system from misbehaving device drivers or hardware.
613 You can find out if your system has an AMD IOMMU if you look into
614 your BIOS for an option to enable it or if you have an IVRS ACPI
617 config AMD_IOMMU_STATS
618 bool "Export AMD IOMMU statistics to debugfs"
622 This option enables code in the AMD IOMMU driver to collect various
623 statistics about whats happening in the driver and exports that
624 information to userspace via debugfs.
627 # need this always selected by IOMMU for the VIA workaround
631 Support for software bounce buffers used on x86-64 systems
632 which don't have a hardware IOMMU (e.g. the current generation
633 of Intel's x86-64 CPUs). Using this PCI devices which can only
634 access 32-bits of memory can be used on systems with more than
635 3 GB of memory. If unsure, say Y.
638 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
641 def_bool (AMD_IOMMU || DMAR)
644 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
645 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
646 select CPUMASK_OFFSTACK
649 Configure maximum number of CPUS and NUMA Nodes for this architecture.
653 int "Maximum number of CPUs" if SMP && !MAXSMP
654 range 2 512 if SMP && !MAXSMP
656 default "4096" if MAXSMP
657 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
660 This allows you to specify the maximum number of CPUs which this
661 kernel will support. The maximum supported value is 512 and the
662 minimum value which makes sense is 2.
664 This is purely to save memory - each supported CPU adds
665 approximately eight kilobytes to the kernel image.
668 bool "SMT (Hyperthreading) scheduler support"
671 SMT scheduler support improves the CPU scheduler's decision making
672 when dealing with Intel Pentium 4 chips with HyperThreading at a
673 cost of slightly increased overhead in some places. If unsure say
678 prompt "Multi-core scheduler support"
681 Multi-core scheduler support improves the CPU scheduler's decision
682 making when dealing with multi-core CPU chips at a cost of slightly
683 increased overhead in some places. If unsure say N here.
685 source "kernel/Kconfig.preempt"
688 bool "Local APIC support on uniprocessors"
689 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
691 A local APIC (Advanced Programmable Interrupt Controller) is an
692 integrated interrupt controller in the CPU. If you have a single-CPU
693 system which has a processor with a local APIC, you can say Y here to
694 enable and use it. If you say Y here even though your machine doesn't
695 have a local APIC, then the kernel will still run with no slowdown at
696 all. The local APIC supports CPU-generated self-interrupts (timer,
697 performance counters), and the NMI watchdog which detects hard
701 bool "IO-APIC support on uniprocessors"
702 depends on X86_UP_APIC
704 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
705 SMP-capable replacement for PC-style interrupt controllers. Most
706 SMP systems and many recent uniprocessor systems have one.
708 If you have a single-CPU system with an IO-APIC, you can say Y here
709 to use it. If you say Y here even though your machine doesn't have
710 an IO-APIC, then the kernel will still run with no slowdown at all.
712 config X86_LOCAL_APIC
714 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
718 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
720 config X86_VISWS_APIC
722 depends on X86_32 && X86_VISWS
724 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
725 bool "Reroute for broken boot IRQs"
727 depends on X86_IO_APIC
729 This option enables a workaround that fixes a source of
730 spurious interrupts. This is recommended when threaded
731 interrupt handling is used on systems where the generation of
732 superfluous "boot interrupts" cannot be disabled.
734 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
735 entry in the chipset's IO-APIC is masked (as, e.g. the RT
736 kernel does during interrupt handling). On chipsets where this
737 boot IRQ generation cannot be disabled, this workaround keeps
738 the original IRQ line masked so that only the equivalent "boot
739 IRQ" is delivered to the CPUs. The workaround also tells the
740 kernel to set up the IRQ handler on the boot IRQ line. In this
741 way only one interrupt is delivered to the kernel. Otherwise
742 the spurious second interrupt may cause the kernel to bring
743 down (vital) interrupt lines.
745 Only affects "broken" chipsets. Interrupt sharing may be
746 increased on these systems.
749 bool "Machine Check Exception"
751 Machine Check Exception support allows the processor to notify the
752 kernel if it detects a problem (e.g. overheating, component failure).
753 The action the kernel takes depends on the severity of the problem,
754 ranging from a warning message on the console, to halting the machine.
755 Your processor must be a Pentium or newer to support this - check the
756 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
757 have a design flaw which leads to false MCE events - hence MCE is
758 disabled on all P5 processors, unless explicitly enabled with "mce"
759 as a boot argument. Similarly, if MCE is built in and creates a
760 problem on some new non-standard machine, you can boot with "nomce"
761 to disable it. MCE support simply ignores non-MCE processors like
762 the 386 and 486, so nearly everyone can say Y here.
766 prompt "Intel MCE features"
767 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
769 Additional support for intel specific MCE features such as
774 prompt "AMD MCE features"
775 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
777 Additional support for AMD specific MCE features such as
778 the DRAM Error Threshold.
780 config X86_MCE_THRESHOLD
781 depends on X86_MCE_AMD || X86_MCE_INTEL
785 config X86_MCE_NONFATAL
786 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
787 depends on X86_32 && X86_MCE
789 Enabling this feature starts a timer that triggers every 5 seconds which
790 will look at the machine check registers to see if anything happened.
791 Non-fatal problems automatically get corrected (but still logged).
792 Disable this if you don't want to see these messages.
793 Seeing the messages this option prints out may be indicative of dying
794 or out-of-spec (ie, overclocked) hardware.
795 This option only does something on certain CPUs.
796 (AMD Athlon/Duron and Intel Pentium 4)
798 config X86_MCE_P4THERMAL
799 bool "check for P4 thermal throttling interrupt."
800 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
802 Enabling this feature will cause a message to be printed when the P4
803 enters thermal throttling.
806 bool "Enable VM86 support" if EMBEDDED
810 This option is required by programs like DOSEMU to run 16-bit legacy
811 code on X86 processors. It also may be needed by software like
812 XFree86 to initialize some video cards via BIOS. Disabling this
813 option saves about 6k.
816 tristate "Toshiba Laptop support"
819 This adds a driver to safely access the System Management Mode of
820 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
821 not work on models with a Phoenix BIOS. The System Management Mode
822 is used to set the BIOS and power saving options on Toshiba portables.
824 For information on utilities to make use of this driver see the
825 Toshiba Linux utilities web site at:
826 <http://www.buzzard.org.uk/toshiba/>.
828 Say Y if you intend to run this kernel on a Toshiba portable.
832 tristate "Dell laptop support"
834 This adds a driver to safely access the System Management Mode
835 of the CPU on the Dell Inspiron 8000. The System Management Mode
836 is used to read cpu temperature and cooling fan status and to
837 control the fans on the I8K portables.
839 This driver has been tested only on the Inspiron 8000 but it may
840 also work with other Dell laptops. You can force loading on other
841 models by passing the parameter `force=1' to the module. Use at
844 For information on utilities to make use of this driver see the
845 I8K Linux utilities web site at:
846 <http://people.debian.org/~dz/i8k/>
848 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
851 config X86_REBOOTFIXUPS
852 bool "Enable X86 board specific fixups for reboot"
855 This enables chipset and/or board specific fixups to be done
856 in order to get reboot to work correctly. This is only needed on
857 some combinations of hardware and BIOS. The symptom, for which
858 this config is intended, is when reboot ends with a stalled/hung
861 Currently, the only fixup is for the Geode machines using
862 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
864 Say Y if you want to enable the fixup. Currently, it's safe to
865 enable this option even if you don't need it.
869 tristate "/dev/cpu/microcode - microcode support"
872 If you say Y here, you will be able to update the microcode on
873 certain Intel and AMD processors. The Intel support is for the
874 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
875 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
876 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
877 You will obviously need the actual microcode binary data itself
878 which is not shipped with the Linux kernel.
880 This option selects the general module only, you need to select
881 at least one vendor specific module as well.
883 To compile this driver as a module, choose M here: the
884 module will be called microcode.
886 config MICROCODE_INTEL
887 bool "Intel microcode patch loading support"
892 This options enables microcode patch loading support for Intel
895 For latest news and information on obtaining all the required
896 Intel ingredients for this driver, check:
897 <http://www.urbanmyth.org/microcode/>.
900 bool "AMD microcode patch loading support"
904 If you select this option, microcode patch loading support for AMD
905 processors will be enabled.
907 config MICROCODE_OLD_INTERFACE
912 tristate "/dev/cpu/*/msr - Model-specific register support"
914 This device gives privileged processes access to the x86
915 Model-Specific Registers (MSRs). It is a character device with
916 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
917 MSR accesses are directed to a specific CPU on multi-processor
921 tristate "/dev/cpu/*/cpuid - CPU information support"
923 This device gives processes access to the x86 CPUID instruction to
924 be executed on a specific processor. It is a character device
925 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
929 prompt "High Memory Support"
930 default HIGHMEM4G if !X86_NUMAQ
931 default HIGHMEM64G if X86_NUMAQ
936 depends on !X86_NUMAQ
938 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
939 However, the address space of 32-bit x86 processors is only 4
940 Gigabytes large. That means that, if you have a large amount of
941 physical memory, not all of it can be "permanently mapped" by the
942 kernel. The physical memory that's not permanently mapped is called
945 If you are compiling a kernel which will never run on a machine with
946 more than 1 Gigabyte total physical RAM, answer "off" here (default
947 choice and suitable for most users). This will result in a "3GB/1GB"
948 split: 3GB are mapped so that each process sees a 3GB virtual memory
949 space and the remaining part of the 4GB virtual memory space is used
950 by the kernel to permanently map as much physical memory as
953 If the machine has between 1 and 4 Gigabytes physical RAM, then
956 If more than 4 Gigabytes is used then answer "64GB" here. This
957 selection turns Intel PAE (Physical Address Extension) mode on.
958 PAE implements 3-level paging on IA32 processors. PAE is fully
959 supported by Linux, PAE mode is implemented on all recent Intel
960 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
961 then the kernel will not boot on CPUs that don't support PAE!
963 The actual amount of total physical memory will either be
964 auto detected or can be forced by using a kernel command line option
965 such as "mem=256M". (Try "man bootparam" or see the documentation of
966 your boot loader (lilo or loadlin) about how to pass options to the
967 kernel at boot time.)
969 If unsure, say "off".
973 depends on !X86_NUMAQ
975 Select this if you have a 32-bit processor and between 1 and 4
976 gigabytes of physical RAM.
980 depends on !M386 && !M486
983 Select this if you have a 32-bit processor and more than 4
984 gigabytes of physical RAM.
989 depends on EXPERIMENTAL
990 prompt "Memory split" if EMBEDDED
994 Select the desired split between kernel and user memory.
996 If the address range available to the kernel is less than the
997 physical memory installed, the remaining memory will be available
998 as "high memory". Accessing high memory is a little more costly
999 than low memory, as it needs to be mapped into the kernel first.
1000 Note that increasing the kernel address space limits the range
1001 available to user programs, making the address space there
1002 tighter. Selecting anything other than the default 3G/1G split
1003 will also likely make your kernel incompatible with binary-only
1006 If you are not absolutely sure what you are doing, leave this
1010 bool "3G/1G user/kernel split"
1011 config VMSPLIT_3G_OPT
1013 bool "3G/1G user/kernel split (for full 1G low memory)"
1015 bool "2G/2G user/kernel split"
1016 config VMSPLIT_2G_OPT
1018 bool "2G/2G user/kernel split (for full 2G low memory)"
1020 bool "1G/3G user/kernel split"
1025 default 0xB0000000 if VMSPLIT_3G_OPT
1026 default 0x80000000 if VMSPLIT_2G
1027 default 0x78000000 if VMSPLIT_2G_OPT
1028 default 0x40000000 if VMSPLIT_1G
1034 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1037 bool "PAE (Physical Address Extension) Support"
1038 depends on X86_32 && !HIGHMEM4G
1040 PAE is required for NX support, and furthermore enables
1041 larger swapspace support for non-overcommit purposes. It
1042 has the cost of more pagetable lookup overhead, and also
1043 consumes more pagetable space per process.
1045 config ARCH_PHYS_ADDR_T_64BIT
1046 def_bool X86_64 || X86_PAE
1048 config DIRECT_GBPAGES
1049 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1053 Allow the kernel linear mapping to use 1GB pages on CPUs that
1054 support it. This can improve the kernel's performance a tiny bit by
1055 reducing TLB pressure. If in doubt, say "Y".
1057 # Common NUMA Features
1059 bool "Numa Memory Allocation and Scheduler Support"
1061 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1062 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1064 Enable NUMA (Non Uniform Memory Access) support.
1066 The kernel will try to allocate memory used by a CPU on the
1067 local memory controller of the CPU and add some more
1068 NUMA awareness to the kernel.
1070 For 64-bit this is recommended if the system is Intel Core i7
1071 (or later), AMD Opteron, or EM64T NUMA.
1073 For 32-bit this is only needed on (rare) 32-bit-only platforms
1074 that support NUMA topologies, such as NUMAQ / Summit, or if you
1075 boot a 32-bit kernel on a 64-bit NUMA platform.
1077 Otherwise, you should say N.
1079 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1080 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1084 prompt "Old style AMD Opteron NUMA detection"
1085 depends on X86_64 && NUMA && PCI
1087 Enable K8 NUMA node topology detection. You should say Y here if
1088 you have a multi processor AMD K8 system. This uses an old
1089 method to read the NUMA configuration directly from the builtin
1090 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1091 instead, which also takes priority if both are compiled in.
1093 config X86_64_ACPI_NUMA
1095 prompt "ACPI NUMA detection"
1096 depends on X86_64 && NUMA && ACPI && PCI
1099 Enable ACPI SRAT based node topology detection.
1101 # Some NUMA nodes have memory ranges that span
1102 # other nodes. Even though a pfn is valid and
1103 # between a node's start and end pfns, it may not
1104 # reside on that node. See memmap_init_zone()
1106 config NODES_SPAN_OTHER_NODES
1108 depends on X86_64_ACPI_NUMA
1111 bool "NUMA emulation"
1112 depends on X86_64 && NUMA
1114 Enable NUMA emulation. A flat machine will be split
1115 into virtual nodes when booted with "numa=fake=N", where N is the
1116 number of nodes. This is only useful for debugging.
1119 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1121 default "9" if MAXSMP
1122 default "6" if X86_64
1123 default "4" if X86_NUMAQ
1125 depends on NEED_MULTIPLE_NODES
1127 Specify the maximum number of NUMA Nodes available on the target
1128 system. Increases memory reserved to accomodate various tables.
1130 config HAVE_ARCH_BOOTMEM_NODE
1132 depends on X86_32 && NUMA
1134 config ARCH_HAVE_MEMORY_PRESENT
1136 depends on X86_32 && DISCONTIGMEM
1138 config NEED_NODE_MEMMAP_SIZE
1140 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1142 config HAVE_ARCH_ALLOC_REMAP
1144 depends on X86_32 && NUMA
1146 config ARCH_FLATMEM_ENABLE
1148 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1150 config ARCH_DISCONTIGMEM_ENABLE
1152 depends on NUMA && X86_32
1154 config ARCH_DISCONTIGMEM_DEFAULT
1156 depends on NUMA && X86_32
1158 config ARCH_SPARSEMEM_DEFAULT
1162 config ARCH_SPARSEMEM_ENABLE
1164 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1165 select SPARSEMEM_STATIC if X86_32
1166 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1168 config ARCH_SELECT_MEMORY_MODEL
1170 depends on ARCH_SPARSEMEM_ENABLE
1172 config ARCH_MEMORY_PROBE
1174 depends on MEMORY_HOTPLUG
1179 bool "Allocate 3rd-level pagetables from highmem"
1180 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1182 The VM uses one page table entry for each page of physical memory.
1183 For systems with a lot of RAM, this can be wasteful of precious
1184 low memory. Setting this option will put user-space page table
1185 entries in high memory.
1187 config X86_CHECK_BIOS_CORRUPTION
1188 bool "Check for low memory corruption"
1190 Periodically check for memory corruption in low memory, which
1191 is suspected to be caused by BIOS. Even when enabled in the
1192 configuration, it is disabled at runtime. Enable it by
1193 setting "memory_corruption_check=1" on the kernel command
1194 line. By default it scans the low 64k of memory every 60
1195 seconds; see the memory_corruption_check_size and
1196 memory_corruption_check_period parameters in
1197 Documentation/kernel-parameters.txt to adjust this.
1199 When enabled with the default parameters, this option has
1200 almost no overhead, as it reserves a relatively small amount
1201 of memory and scans it infrequently. It both detects corruption
1202 and prevents it from affecting the running system.
1204 It is, however, intended as a diagnostic tool; if repeatable
1205 BIOS-originated corruption always affects the same memory,
1206 you can use memmap= to prevent the kernel from using that
1209 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1210 bool "Set the default setting of memory_corruption_check"
1211 depends on X86_CHECK_BIOS_CORRUPTION
1214 Set whether the default state of memory_corruption_check is
1217 config X86_RESERVE_LOW_64K
1218 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1221 Reserve the first 64K of physical RAM on BIOSes that are known
1222 to potentially corrupt that memory range. A numbers of BIOSes are
1223 known to utilize this area during suspend/resume, so it must not
1224 be used by the kernel.
1226 Set this to N if you are absolutely sure that you trust the BIOS
1227 to get all its memory reservations and usages right.
1229 If you have doubts about the BIOS (e.g. suspend/resume does not
1230 work or there's kernel crashes after certain hardware hotplug
1231 events) and it's not AMI or Phoenix, then you might want to enable
1232 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1233 corruption patterns.
1237 config MATH_EMULATION
1239 prompt "Math emulation" if X86_32
1241 Linux can emulate a math coprocessor (used for floating point
1242 operations) if you don't have one. 486DX and Pentium processors have
1243 a math coprocessor built in, 486SX and 386 do not, unless you added
1244 a 487DX or 387, respectively. (The messages during boot time can
1245 give you some hints here ["man dmesg"].) Everyone needs either a
1246 coprocessor or this emulation.
1248 If you don't have a math coprocessor, you need to say Y here; if you
1249 say Y here even though you have a coprocessor, the coprocessor will
1250 be used nevertheless. (This behavior can be changed with the kernel
1251 command line option "no387", which comes handy if your coprocessor
1252 is broken. Try "man bootparam" or see the documentation of your boot
1253 loader (lilo or loadlin) about how to pass options to the kernel at
1254 boot time.) This means that it is a good idea to say Y here if you
1255 intend to use this kernel on different machines.
1257 More information about the internals of the Linux math coprocessor
1258 emulation can be found in <file:arch/x86/math-emu/README>.
1260 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1261 kernel, it won't hurt.
1264 bool "MTRR (Memory Type Range Register) support"
1266 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1267 the Memory Type Range Registers (MTRRs) may be used to control
1268 processor access to memory ranges. This is most useful if you have
1269 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1270 allows bus write transfers to be combined into a larger transfer
1271 before bursting over the PCI/AGP bus. This can increase performance
1272 of image write operations 2.5 times or more. Saying Y here creates a
1273 /proc/mtrr file which may be used to manipulate your processor's
1274 MTRRs. Typically the X server should use this.
1276 This code has a reasonably generic interface so that similar
1277 control registers on other processors can be easily supported
1280 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1281 Registers (ARRs) which provide a similar functionality to MTRRs. For
1282 these, the ARRs are used to emulate the MTRRs.
1283 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1284 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1285 write-combining. All of these processors are supported by this code
1286 and it makes sense to say Y here if you have one of them.
1288 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1289 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1290 can lead to all sorts of problems, so it's good to say Y here.
1292 You can safely say Y even if your machine doesn't have MTRRs, you'll
1293 just add about 9 KB to your kernel.
1295 See <file:Documentation/x86/mtrr.txt> for more information.
1297 config MTRR_SANITIZER
1299 prompt "MTRR cleanup support"
1302 Convert MTRR layout from continuous to discrete, so X drivers can
1303 add writeback entries.
1305 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1306 The largest mtrr entry size for a continous block can be set with
1311 config MTRR_SANITIZER_ENABLE_DEFAULT
1312 int "MTRR cleanup enable value (0-1)"
1315 depends on MTRR_SANITIZER
1317 Enable mtrr cleanup default value
1319 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1320 int "MTRR cleanup spare reg num (0-7)"
1323 depends on MTRR_SANITIZER
1325 mtrr cleanup spare entries default, it can be changed via
1326 mtrr_spare_reg_nr=N on the kernel command line.
1330 prompt "x86 PAT support"
1333 Use PAT attributes to setup page level cache control.
1335 PATs are the modern equivalents of MTRRs and are much more
1336 flexible than MTRRs.
1338 Say N here if you see bootup problems (boot crash, boot hang,
1339 spontaneous reboots) or a non-working video driver.
1344 bool "EFI runtime service support"
1347 This enables the kernel to use EFI runtime services that are
1348 available (such as the EFI variable services).
1350 This option is only useful on systems that have EFI firmware.
1351 In addition, you should use the latest ELILO loader available
1352 at <http://elilo.sourceforge.net> in order to take advantage
1353 of EFI runtime services. However, even with this option, the
1354 resultant kernel should continue to boot on existing non-EFI
1359 prompt "Enable seccomp to safely compute untrusted bytecode"
1361 This kernel feature is useful for number crunching applications
1362 that may need to compute untrusted bytecode during their
1363 execution. By using pipes or other transports made available to
1364 the process as file descriptors supporting the read/write
1365 syscalls, it's possible to isolate those applications in
1366 their own address space using seccomp. Once seccomp is
1367 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1368 and the task is only allowed to execute a few safe syscalls
1369 defined by each seccomp mode.
1371 If unsure, say Y. Only embedded should say N here.
1373 config CC_STACKPROTECTOR_ALL
1376 config CC_STACKPROTECTOR
1377 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1378 select CC_STACKPROTECTOR_ALL
1380 This option turns on the -fstack-protector GCC feature. This
1381 feature puts, at the beginning of functions, a canary value on
1382 the stack just before the return address, and validates
1383 the value just before actually returning. Stack based buffer
1384 overflows (that need to overwrite this return address) now also
1385 overwrite the canary, which gets detected and the attack is then
1386 neutralized via a kernel panic.
1388 This feature requires gcc version 4.2 or above, or a distribution
1389 gcc with the feature backported. Older versions are automatically
1390 detected and for those versions, this configuration option is
1391 ignored. (and a warning is printed during bootup)
1393 source kernel/Kconfig.hz
1396 bool "kexec system call"
1398 kexec is a system call that implements the ability to shutdown your
1399 current kernel, and to start another kernel. It is like a reboot
1400 but it is independent of the system firmware. And like a reboot
1401 you can start any kernel with it, not just Linux.
1403 The name comes from the similarity to the exec system call.
1405 It is an ongoing process to be certain the hardware in a machine
1406 is properly shutdown, so do not be surprised if this code does not
1407 initially work for you. It may help to enable device hotplugging
1408 support. As of this writing the exact hardware interface is
1409 strongly in flux, so no good recommendation can be made.
1412 bool "kernel crash dumps"
1413 depends on X86_64 || (X86_32 && HIGHMEM)
1415 Generate crash dump after being started by kexec.
1416 This should be normally only set in special crash dump kernels
1417 which are loaded in the main kernel with kexec-tools into
1418 a specially reserved region and then later executed after
1419 a crash by kdump/kexec. The crash dump kernel must be compiled
1420 to a memory address not used by the main kernel or BIOS using
1421 PHYSICAL_START, or it must be built as a relocatable image
1422 (CONFIG_RELOCATABLE=y).
1423 For more details see Documentation/kdump/kdump.txt
1426 bool "kexec jump (EXPERIMENTAL)"
1427 depends on EXPERIMENTAL
1428 depends on KEXEC && HIBERNATION && X86_32
1430 Jump between original kernel and kexeced kernel and invoke
1431 code in physical address mode via KEXEC
1433 config PHYSICAL_START
1434 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1435 default "0x1000000" if X86_NUMAQ
1436 default "0x200000" if X86_64
1439 This gives the physical address where the kernel is loaded.
1441 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1442 bzImage will decompress itself to above physical address and
1443 run from there. Otherwise, bzImage will run from the address where
1444 it has been loaded by the boot loader and will ignore above physical
1447 In normal kdump cases one does not have to set/change this option
1448 as now bzImage can be compiled as a completely relocatable image
1449 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1450 address. This option is mainly useful for the folks who don't want
1451 to use a bzImage for capturing the crash dump and want to use a
1452 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1453 to be specifically compiled to run from a specific memory area
1454 (normally a reserved region) and this option comes handy.
1456 So if you are using bzImage for capturing the crash dump, leave
1457 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1458 Otherwise if you plan to use vmlinux for capturing the crash dump
1459 change this value to start of the reserved region (Typically 16MB
1460 0x1000000). In other words, it can be set based on the "X" value as
1461 specified in the "crashkernel=YM@XM" command line boot parameter
1462 passed to the panic-ed kernel. Typically this parameter is set as
1463 crashkernel=64M@16M. Please take a look at
1464 Documentation/kdump/kdump.txt for more details about crash dumps.
1466 Usage of bzImage for capturing the crash dump is recommended as
1467 one does not have to build two kernels. Same kernel can be used
1468 as production kernel and capture kernel. Above option should have
1469 gone away after relocatable bzImage support is introduced. But it
1470 is present because there are users out there who continue to use
1471 vmlinux for dump capture. This option should go away down the
1474 Don't change this unless you know what you are doing.
1477 bool "Build a relocatable kernel (EXPERIMENTAL)"
1478 depends on EXPERIMENTAL
1480 This builds a kernel image that retains relocation information
1481 so it can be loaded someplace besides the default 1MB.
1482 The relocations tend to make the kernel binary about 10% larger,
1483 but are discarded at runtime.
1485 One use is for the kexec on panic case where the recovery kernel
1486 must live at a different physical address than the primary
1489 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1490 it has been loaded at and the compile time physical address
1491 (CONFIG_PHYSICAL_START) is ignored.
1493 config PHYSICAL_ALIGN
1495 prompt "Alignment value to which kernel should be aligned" if X86_32
1496 default "0x100000" if X86_32
1497 default "0x200000" if X86_64
1498 range 0x2000 0x400000
1500 This value puts the alignment restrictions on physical address
1501 where kernel is loaded and run from. Kernel is compiled for an
1502 address which meets above alignment restriction.
1504 If bootloader loads the kernel at a non-aligned address and
1505 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1506 address aligned to above value and run from there.
1508 If bootloader loads the kernel at a non-aligned address and
1509 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1510 load address and decompress itself to the address it has been
1511 compiled for and run from there. The address for which kernel is
1512 compiled already meets above alignment restrictions. Hence the
1513 end result is that kernel runs from a physical address meeting
1514 above alignment restrictions.
1516 Don't change this unless you know what you are doing.
1519 bool "Support for hot-pluggable CPUs"
1520 depends on SMP && HOTPLUG
1522 Say Y here to allow turning CPUs off and on. CPUs can be
1523 controlled through /sys/devices/system/cpu.
1524 ( Note: power management support will enable this option
1525 automatically on SMP systems. )
1526 Say N if you want to disable CPU hotplug.
1530 prompt "Compat VDSO support"
1531 depends on X86_32 || IA32_EMULATION
1533 Map the 32-bit VDSO to the predictable old-style address too.
1535 Say N here if you are running a sufficiently recent glibc
1536 version (2.3.3 or later), to remove the high-mapped
1537 VDSO mapping and to exclusively use the randomized VDSO.
1542 bool "Built-in kernel command line"
1545 Allow for specifying boot arguments to the kernel at
1546 build time. On some systems (e.g. embedded ones), it is
1547 necessary or convenient to provide some or all of the
1548 kernel boot arguments with the kernel itself (that is,
1549 to not rely on the boot loader to provide them.)
1551 To compile command line arguments into the kernel,
1552 set this option to 'Y', then fill in the
1553 the boot arguments in CONFIG_CMDLINE.
1555 Systems with fully functional boot loaders (i.e. non-embedded)
1556 should leave this option set to 'N'.
1559 string "Built-in kernel command string"
1560 depends on CMDLINE_BOOL
1563 Enter arguments here that should be compiled into the kernel
1564 image and used at boot time. If the boot loader provides a
1565 command line at boot time, it is appended to this string to
1566 form the full kernel command line, when the system boots.
1568 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1569 change this behavior.
1571 In most cases, the command line (whether built-in or provided
1572 by the boot loader) should specify the device for the root
1575 config CMDLINE_OVERRIDE
1576 bool "Built-in command line overrides boot loader arguments"
1578 depends on CMDLINE_BOOL
1580 Set this option to 'Y' to have the kernel ignore the boot loader
1581 command line, and use ONLY the built-in command line.
1583 This is used to work around broken boot loaders. This should
1584 be set to 'N' under normal conditions.
1588 config ARCH_ENABLE_MEMORY_HOTPLUG
1590 depends on X86_64 || (X86_32 && HIGHMEM)
1592 config ARCH_ENABLE_MEMORY_HOTREMOVE
1594 depends on MEMORY_HOTPLUG
1596 config HAVE_ARCH_EARLY_PFN_TO_NID
1600 menu "Power management and ACPI options"
1602 config ARCH_HIBERNATION_HEADER
1604 depends on X86_64 && HIBERNATION
1606 source "kernel/power/Kconfig"
1608 source "drivers/acpi/Kconfig"
1613 depends on APM || APM_MODULE
1616 tristate "APM (Advanced Power Management) BIOS support"
1617 depends on X86_32 && PM_SLEEP
1619 APM is a BIOS specification for saving power using several different
1620 techniques. This is mostly useful for battery powered laptops with
1621 APM compliant BIOSes. If you say Y here, the system time will be
1622 reset after a RESUME operation, the /proc/apm device will provide
1623 battery status information, and user-space programs will receive
1624 notification of APM "events" (e.g. battery status change).
1626 If you select "Y" here, you can disable actual use of the APM
1627 BIOS by passing the "apm=off" option to the kernel at boot time.
1629 Note that the APM support is almost completely disabled for
1630 machines with more than one CPU.
1632 In order to use APM, you will need supporting software. For location
1633 and more information, read <file:Documentation/power/pm.txt> and the
1634 Battery Powered Linux mini-HOWTO, available from
1635 <http://www.tldp.org/docs.html#howto>.
1637 This driver does not spin down disk drives (see the hdparm(8)
1638 manpage ("man 8 hdparm") for that), and it doesn't turn off
1639 VESA-compliant "green" monitors.
1641 This driver does not support the TI 4000M TravelMate and the ACER
1642 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1643 desktop machines also don't have compliant BIOSes, and this driver
1644 may cause those machines to panic during the boot phase.
1646 Generally, if you don't have a battery in your machine, there isn't
1647 much point in using this driver and you should say N. If you get
1648 random kernel OOPSes or reboots that don't seem to be related to
1649 anything, try disabling/enabling this option (or disabling/enabling
1652 Some other things you should try when experiencing seemingly random,
1655 1) make sure that you have enough swap space and that it is
1657 2) pass the "no-hlt" option to the kernel
1658 3) switch on floating point emulation in the kernel and pass
1659 the "no387" option to the kernel
1660 4) pass the "floppy=nodma" option to the kernel
1661 5) pass the "mem=4M" option to the kernel (thereby disabling
1662 all but the first 4 MB of RAM)
1663 6) make sure that the CPU is not over clocked.
1664 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1665 8) disable the cache from your BIOS settings
1666 9) install a fan for the video card or exchange video RAM
1667 10) install a better fan for the CPU
1668 11) exchange RAM chips
1669 12) exchange the motherboard.
1671 To compile this driver as a module, choose M here: the
1672 module will be called apm.
1676 config APM_IGNORE_USER_SUSPEND
1677 bool "Ignore USER SUSPEND"
1679 This option will ignore USER SUSPEND requests. On machines with a
1680 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1681 series notebooks, it is necessary to say Y because of a BIOS bug.
1683 config APM_DO_ENABLE
1684 bool "Enable PM at boot time"
1686 Enable APM features at boot time. From page 36 of the APM BIOS
1687 specification: "When disabled, the APM BIOS does not automatically
1688 power manage devices, enter the Standby State, enter the Suspend
1689 State, or take power saving steps in response to CPU Idle calls."
1690 This driver will make CPU Idle calls when Linux is idle (unless this
1691 feature is turned off -- see "Do CPU IDLE calls", below). This
1692 should always save battery power, but more complicated APM features
1693 will be dependent on your BIOS implementation. You may need to turn
1694 this option off if your computer hangs at boot time when using APM
1695 support, or if it beeps continuously instead of suspending. Turn
1696 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1697 T400CDT. This is off by default since most machines do fine without
1701 bool "Make CPU Idle calls when idle"
1703 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1704 On some machines, this can activate improved power savings, such as
1705 a slowed CPU clock rate, when the machine is idle. These idle calls
1706 are made after the idle loop has run for some length of time (e.g.,
1707 333 mS). On some machines, this will cause a hang at boot time or
1708 whenever the CPU becomes idle. (On machines with more than one CPU,
1709 this option does nothing.)
1711 config APM_DISPLAY_BLANK
1712 bool "Enable console blanking using APM"
1714 Enable console blanking using the APM. Some laptops can use this to
1715 turn off the LCD backlight when the screen blanker of the Linux
1716 virtual console blanks the screen. Note that this is only used by
1717 the virtual console screen blanker, and won't turn off the backlight
1718 when using the X Window system. This also doesn't have anything to
1719 do with your VESA-compliant power-saving monitor. Further, this
1720 option doesn't work for all laptops -- it might not turn off your
1721 backlight at all, or it might print a lot of errors to the console,
1722 especially if you are using gpm.
1724 config APM_ALLOW_INTS
1725 bool "Allow interrupts during APM BIOS calls"
1727 Normally we disable external interrupts while we are making calls to
1728 the APM BIOS as a measure to lessen the effects of a badly behaving
1729 BIOS implementation. The BIOS should reenable interrupts if it
1730 needs to. Unfortunately, some BIOSes do not -- especially those in
1731 many of the newer IBM Thinkpads. If you experience hangs when you
1732 suspend, try setting this to Y. Otherwise, say N.
1736 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1738 source "drivers/cpuidle/Kconfig"
1740 source "drivers/idle/Kconfig"
1745 menu "Bus options (PCI etc.)"
1750 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1752 Find out whether you have a PCI motherboard. PCI is the name of a
1753 bus system, i.e. the way the CPU talks to the other stuff inside
1754 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1755 VESA. If you have PCI, say Y, otherwise N.
1758 prompt "PCI access mode"
1759 depends on X86_32 && PCI
1762 On PCI systems, the BIOS can be used to detect the PCI devices and
1763 determine their configuration. However, some old PCI motherboards
1764 have BIOS bugs and may crash if this is done. Also, some embedded
1765 PCI-based systems don't have any BIOS at all. Linux can also try to
1766 detect the PCI hardware directly without using the BIOS.
1768 With this option, you can specify how Linux should detect the
1769 PCI devices. If you choose "BIOS", the BIOS will be used,
1770 if you choose "Direct", the BIOS won't be used, and if you
1771 choose "MMConfig", then PCI Express MMCONFIG will be used.
1772 If you choose "Any", the kernel will try MMCONFIG, then the
1773 direct access method and falls back to the BIOS if that doesn't
1774 work. If unsure, go with the default, which is "Any".
1779 config PCI_GOMMCONFIG
1796 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1798 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1801 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1805 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1809 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1816 bool "Support mmconfig PCI config space access"
1817 depends on X86_64 && PCI && ACPI
1820 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1821 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1823 DMA remapping (DMAR) devices support enables independent address
1824 translations for Direct Memory Access (DMA) from devices.
1825 These DMA remapping devices are reported via ACPI tables
1826 and include PCI device scope covered by these DMA
1829 config DMAR_DEFAULT_ON
1831 prompt "Enable DMA Remapping Devices by default"
1834 Selecting this option will enable a DMAR device at boot time if
1835 one is found. If this option is not selected, DMAR support can
1836 be enabled by passing intel_iommu=on to the kernel. It is
1837 recommended you say N here while the DMAR code remains
1842 prompt "Support for Graphics workaround"
1845 Current Graphics drivers tend to use physical address
1846 for DMA and avoid using DMA APIs. Setting this config
1847 option permits the IOMMU driver to set a unity map for
1848 all the OS-visible memory. Hence the driver can continue
1849 to use physical addresses for DMA.
1851 config DMAR_FLOPPY_WA
1855 Floppy disk drivers are know to bypass DMA API calls
1856 thereby failing to work when IOMMU is enabled. This
1857 workaround will setup a 1:1 mapping for the first
1858 16M to make floppy (an ISA device) work.
1861 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1862 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1865 Supports Interrupt remapping for IO-APIC and MSI devices.
1866 To use x2apic mode in the CPU's which support x2APIC enhancements or
1867 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1869 source "drivers/pci/pcie/Kconfig"
1871 source "drivers/pci/Kconfig"
1873 # x86_64 have no ISA slots, but do have ISA-style DMA.
1882 Find out whether you have ISA slots on your motherboard. ISA is the
1883 name of a bus system, i.e. the way the CPU talks to the other stuff
1884 inside your box. Other bus systems are PCI, EISA, MicroChannel
1885 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1886 newer boards don't support it. If you have ISA, say Y, otherwise N.
1892 The Extended Industry Standard Architecture (EISA) bus was
1893 developed as an open alternative to the IBM MicroChannel bus.
1895 The EISA bus provided some of the features of the IBM MicroChannel
1896 bus while maintaining backward compatibility with cards made for
1897 the older ISA bus. The EISA bus saw limited use between 1988 and
1898 1995 when it was made obsolete by the PCI bus.
1900 Say Y here if you are building a kernel for an EISA-based machine.
1904 source "drivers/eisa/Kconfig"
1909 MicroChannel Architecture is found in some IBM PS/2 machines and
1910 laptops. It is a bus system similar to PCI or ISA. See
1911 <file:Documentation/mca.txt> (and especially the web page given
1912 there) before attempting to build an MCA bus kernel.
1914 source "drivers/mca/Kconfig"
1917 tristate "NatSemi SCx200 support"
1919 This provides basic support for National Semiconductor's
1920 (now AMD's) Geode processors. The driver probes for the
1921 PCI-IDs of several on-chip devices, so its a good dependency
1922 for other scx200_* drivers.
1924 If compiled as a module, the driver is named scx200.
1926 config SCx200HR_TIMER
1927 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1928 depends on SCx200 && GENERIC_TIME
1931 This driver provides a clocksource built upon the on-chip
1932 27MHz high-resolution timer. Its also a workaround for
1933 NSC Geode SC-1100's buggy TSC, which loses time when the
1934 processor goes idle (as is done by the scheduler). The
1935 other workaround is idle=poll boot option.
1937 config GEODE_MFGPT_TIMER
1939 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1940 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1942 This driver provides a clock event source based on the MFGPT
1943 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1944 MFGPTs have a better resolution and max interval than the
1945 generic PIT, and are suitable for use as high-res timers.
1948 bool "One Laptop Per Child support"
1951 Add support for detecting the unique features of the OLPC
1958 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1960 source "drivers/pcmcia/Kconfig"
1962 source "drivers/pci/hotplug/Kconfig"
1967 menu "Executable file formats / Emulations"
1969 source "fs/Kconfig.binfmt"
1971 config IA32_EMULATION
1972 bool "IA32 Emulation"
1974 select COMPAT_BINFMT_ELF
1976 Include code to run 32-bit programs under a 64-bit kernel. You should
1977 likely turn this on, unless you're 100% sure that you don't have any
1978 32-bit programs left.
1981 tristate "IA32 a.out support"
1982 depends on IA32_EMULATION
1984 Support old a.out binaries in the 32bit emulation.
1988 depends on IA32_EMULATION
1990 config COMPAT_FOR_U64_ALIGNMENT
1994 config SYSVIPC_COMPAT
1996 depends on COMPAT && SYSVIPC
2001 config HAVE_ATOMIC_IOMAP
2005 source "net/Kconfig"
2007 source "drivers/Kconfig"
2009 source "drivers/firmware/Kconfig"
2013 source "arch/x86/Kconfig.debug"
2015 source "security/Kconfig"
2017 source "crypto/Kconfig"
2019 source "arch/x86/kvm/Kconfig"
2021 source "lib/Kconfig"