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_PERF_EVENTS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
35 select HAVE_FTRACE_MCOUNT_RECORD
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
58 select HAVE_ARCH_KMEMCHECK
59 select HAVE_USER_RETURN_NOTIFIER
63 default "elf32-i386" if X86_32
64 default "elf64-x86-64" if X86_64
68 default "arch/x86/configs/i386_defconfig" if X86_32
69 default "arch/x86/configs/x86_64_defconfig" if X86_64
74 config GENERIC_CMOS_UPDATE
77 config CLOCKSOURCE_WATCHDOG
80 config GENERIC_CLOCKEVENTS
83 config GENERIC_CLOCKEVENTS_BROADCAST
85 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
87 config LOCKDEP_SUPPORT
90 config STACKTRACE_SUPPORT
93 config HAVE_LATENCYTOP_SUPPORT
105 config GENERIC_ISA_DMA
114 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
116 config GENERIC_BUG_RELATIVE_POINTERS
119 config GENERIC_HWEIGHT
125 config ARCH_MAY_HAVE_PC_FDC
128 config RWSEM_GENERIC_SPINLOCK
131 config RWSEM_XCHGADD_ALGORITHM
134 config ARCH_HAS_CPU_IDLE_WAIT
137 config GENERIC_CALIBRATE_DELAY
140 config GENERIC_TIME_VSYSCALL
144 config ARCH_HAS_CPU_RELAX
147 config ARCH_HAS_DEFAULT_IDLE
150 config ARCH_HAS_CACHE_LINE_SIZE
153 config HAVE_SETUP_PER_CPU_AREA
156 config NEED_PER_CPU_EMBED_FIRST_CHUNK
159 config NEED_PER_CPU_PAGE_FIRST_CHUNK
162 config HAVE_CPUMASK_OF_CPU_MAP
165 config ARCH_HIBERNATION_POSSIBLE
168 config ARCH_SUSPEND_POSSIBLE
175 config ARCH_POPULATES_NODE_MAP
182 config ARCH_SUPPORTS_OPTIMIZED_INLINING
185 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
188 config HAVE_EARLY_RES
191 config HAVE_INTEL_TXT
193 depends on EXPERIMENTAL && DMAR && ACPI
195 # Use the generic interrupt handling code in kernel/irq/:
196 config GENERIC_HARDIRQS
200 config GENERIC_HARDIRQS_NO__DO_IRQ
203 config GENERIC_IRQ_PROBE
207 config GENERIC_PENDING_IRQ
209 depends on GENERIC_HARDIRQS && SMP
212 config USE_GENERIC_SMP_HELPERS
218 depends on X86_32 && SMP
222 depends on X86_64 && SMP
229 config X86_TRAMPOLINE
231 depends on SMP || (64BIT && ACPI_SLEEP)
234 config X86_32_LAZY_GS
236 depends on X86_32 && !CC_STACKPROTECTOR
240 source "init/Kconfig"
241 source "kernel/Kconfig.freezer"
243 menu "Processor type and features"
245 source "kernel/time/Kconfig"
248 bool "Symmetric multi-processing support"
250 This enables support for systems with more than one CPU. If you have
251 a system with only one CPU, like most personal computers, say N. If
252 you have a system with more than one CPU, say Y.
254 If you say N here, the kernel will run on single and multiprocessor
255 machines, but will use only one CPU of a multiprocessor machine. If
256 you say Y here, the kernel will run on many, but not all,
257 singleprocessor machines. On a singleprocessor machine, the kernel
258 will run faster if you say N here.
260 Note that if you say Y here and choose architecture "586" or
261 "Pentium" under "Processor family", the kernel will not work on 486
262 architectures. Similarly, multiprocessor kernels for the "PPro"
263 architecture may not work on all Pentium based boards.
265 People using multiprocessor machines who say Y here should also say
266 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
267 Management" code will be disabled if you say Y here.
269 See also <file:Documentation/i386/IO-APIC.txt>,
270 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
271 <http://www.tldp.org/docs.html#howto>.
273 If you don't know what to do here, say N.
276 bool "Support x2apic"
277 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
279 This enables x2apic support on CPUs that have this feature.
281 This allows 32-bit apic IDs (so it can support very large systems),
282 and accesses the local apic via MSRs not via mmio.
284 If you don't know what to do here, say N.
287 bool "Support sparse irq numbering"
288 depends on PCI_MSI || HT_IRQ
290 This enables support for sparse irqs. This is useful for distro
291 kernels that want to define a high CONFIG_NR_CPUS value but still
292 want to have low kernel memory footprint on smaller machines.
294 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
295 out the irq_desc[] array in a more NUMA-friendly way. )
297 If you don't know what to do here, say N.
301 depends on SPARSE_IRQ && NUMA
304 bool "Enable MPS table" if ACPI
306 depends on X86_LOCAL_APIC
308 For old smp systems that do not have proper acpi support. Newer systems
309 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
312 bool "Support for big SMP systems with more than 8 CPUs"
313 depends on X86_32 && SMP
315 This option is needed for the systems that have more than 8 CPUs
318 config X86_EXTENDED_PLATFORM
319 bool "Support for extended (non-PC) x86 platforms"
322 If you disable this option then the kernel will only support
323 standard PC platforms. (which covers the vast majority of
326 If you enable this option then you'll be able to select support
327 for the following (non-PC) 32 bit x86 platforms:
331 SGI 320/540 (Visual Workstation)
332 Summit/EXA (IBM x440)
333 Unisys ES7000 IA32 series
334 Moorestown MID devices
336 If you have one of these systems, or if you want to build a
337 generic distribution kernel, say Y here - otherwise say N.
341 config X86_EXTENDED_PLATFORM
342 bool "Support for extended (non-PC) x86 platforms"
345 If you disable this option then the kernel will only support
346 standard PC platforms. (which covers the vast majority of
349 If you enable this option then you'll be able to select support
350 for the following (non-PC) 64 bit x86 platforms:
354 If you have one of these systems, or if you want to build a
355 generic distribution kernel, say Y here - otherwise say N.
357 # This is an alphabetically sorted list of 64 bit extended platforms
358 # Please maintain the alphabetic order if and when there are additions
363 depends on X86_64 && PCI
364 depends on X86_EXTENDED_PLATFORM
366 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
367 supposed to run on these EM64T-based machines. Only choose this option
368 if you have one of these machines.
371 bool "SGI Ultraviolet"
373 depends on X86_EXTENDED_PLATFORM
375 depends on X86_X2APIC
377 This option is needed in order to support SGI Ultraviolet systems.
378 If you don't have one of these, you should say N here.
380 # Following is an alphabetically sorted list of 32 bit extended platforms
381 # Please maintain the alphabetic order if and when there are additions
386 depends on X86_EXTENDED_PLATFORM
388 Select this for an AMD Elan processor.
390 Do not use this option for K6/Athlon/Opteron processors!
392 If unsure, choose "PC-compatible" instead.
395 bool "Moorestown MID platform"
397 depends on X86_EXTENDED_PLATFORM
399 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
400 Internet Device(MID) platform. Moorestown consists of two chips:
401 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
402 Unlike standard x86 PCs, Moorestown does not have many legacy devices
403 nor standard legacy replacement devices/features. e.g. Moorestown does
404 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
407 bool "RDC R-321x SoC"
409 depends on X86_EXTENDED_PLATFORM
411 select X86_REBOOTFIXUPS
413 This option is needed for RDC R-321x system-on-chip, also known
415 If you don't have one of these chips, you should say N here.
417 config X86_32_NON_STANDARD
418 bool "Support non-standard 32-bit SMP architectures"
419 depends on X86_32 && SMP
420 depends on X86_EXTENDED_PLATFORM
422 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
423 subarchitectures. It is intended for a generic binary kernel.
424 if you select them all, kernel will probe it one by one. and will
427 # Alphabetically sorted list of Non standard 32 bit platforms
430 bool "NUMAQ (IBM/Sequent)"
431 depends on X86_32_NON_STANDARD
435 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
436 NUMA multiquad box. This changes the way that processors are
437 bootstrapped, and uses Clustered Logical APIC addressing mode instead
438 of Flat Logical. You will need a new lynxer.elf file to flash your
439 firmware with - send email to <Martin.Bligh@us.ibm.com>.
441 config X86_SUPPORTS_MEMORY_FAILURE
443 # MCE code calls memory_failure():
445 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
446 depends on !X86_NUMAQ
447 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
448 depends on X86_64 || !SPARSEMEM
449 select ARCH_SUPPORTS_MEMORY_FAILURE
453 bool "SGI 320/540 (Visual Workstation)"
454 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
455 depends on X86_32_NON_STANDARD
457 The SGI Visual Workstation series is an IA32-based workstation
458 based on SGI systems chips with some legacy PC hardware attached.
460 Say Y here to create a kernel to run on the SGI 320 or 540.
462 A kernel compiled for the Visual Workstation will run on general
463 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
466 bool "Summit/EXA (IBM x440)"
467 depends on X86_32_NON_STANDARD
469 This option is needed for IBM systems that use the Summit/EXA chipset.
470 In particular, it is needed for the x440.
473 bool "Unisys ES7000 IA32 series"
474 depends on X86_32_NON_STANDARD && X86_BIGSMP
476 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
477 supposed to run on an IA32-based Unisys ES7000 system.
479 config SCHED_OMIT_FRAME_POINTER
481 prompt "Single-depth WCHAN output"
484 Calculate simpler /proc/<PID>/wchan values. If this option
485 is disabled then wchan values will recurse back to the
486 caller function. This provides more accurate wchan values,
487 at the expense of slightly more scheduling overhead.
489 If in doubt, say "Y".
491 menuconfig PARAVIRT_GUEST
492 bool "Paravirtualized guest support"
494 Say Y here to get to see options related to running Linux under
495 various hypervisors. This option alone does not add any kernel code.
497 If you say N, all options in this submenu will be skipped and disabled.
501 source "arch/x86/xen/Kconfig"
504 bool "VMI Guest support (DEPRECATED)"
508 VMI provides a paravirtualized interface to the VMware ESX server
509 (it could be used by other hypervisors in theory too, but is not
510 at the moment), by linking the kernel to a GPL-ed ROM module
511 provided by the hypervisor.
513 As of September 2009, VMware has started a phased retirement
514 of this feature from VMware's products. Please see
515 feature-removal-schedule.txt for details. If you are
516 planning to enable this option, please note that you cannot
517 live migrate a VMI enabled VM to a future VMware product,
518 which doesn't support VMI. So if you expect your kernel to
519 seamlessly migrate to newer VMware products, keep this
523 bool "KVM paravirtualized clock"
525 select PARAVIRT_CLOCK
527 Turning on this option will allow you to run a paravirtualized clock
528 when running over the KVM hypervisor. Instead of relying on a PIT
529 (or probably other) emulation by the underlying device model, the host
530 provides the guest with timing infrastructure such as time of day, and
534 bool "KVM Guest support"
537 This option enables various optimizations for running under the KVM
540 source "arch/x86/lguest/Kconfig"
543 bool "Enable paravirtualization code"
545 This changes the kernel so it can modify itself when it is run
546 under a hypervisor, potentially improving performance significantly
547 over full virtualization. However, when run without a hypervisor
548 the kernel is theoretically slower and slightly larger.
550 config PARAVIRT_SPINLOCKS
551 bool "Paravirtualization layer for spinlocks"
552 depends on PARAVIRT && SMP && EXPERIMENTAL
554 Paravirtualized spinlocks allow a pvops backend to replace the
555 spinlock implementation with something virtualization-friendly
556 (for example, block the virtual CPU rather than spinning).
558 Unfortunately the downside is an up to 5% performance hit on
559 native kernels, with various workloads.
561 If you are unsure how to answer this question, answer N.
563 config PARAVIRT_CLOCK
569 config PARAVIRT_DEBUG
570 bool "paravirt-ops debugging"
571 depends on PARAVIRT && DEBUG_KERNEL
573 Enable to debug paravirt_ops internals. Specifically, BUG if
574 a paravirt_op is missing when it is called.
578 bool "Disable Bootmem code"
580 Use early_res directly instead of bootmem before slab is ready.
581 - allocator (buddy) [generic]
582 - early allocator (bootmem) [generic]
583 - very early allocator (reserve_early*()) [x86]
584 - very very early allocator (early brk model) [x86]
585 So reduce one layer between early allocator to final allocator
591 This option adds a kernel parameter 'memtest', which allows memtest
593 memtest=0, mean disabled; -- default
594 memtest=1, mean do 1 test pattern;
596 memtest=4, mean do 4 test patterns.
597 If you are unsure how to answer this question, answer N.
599 config X86_SUMMIT_NUMA
601 depends on X86_32 && NUMA && X86_32_NON_STANDARD
603 config X86_CYCLONE_TIMER
605 depends on X86_32_NON_STANDARD
607 source "arch/x86/Kconfig.cpu"
611 prompt "HPET Timer Support" if X86_32
613 Use the IA-PC HPET (High Precision Event Timer) to manage
614 time in preference to the PIT and RTC, if a HPET is
616 HPET is the next generation timer replacing legacy 8254s.
617 The HPET provides a stable time base on SMP
618 systems, unlike the TSC, but it is more expensive to access,
619 as it is off-chip. You can find the HPET spec at
620 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
622 You can safely choose Y here. However, HPET will only be
623 activated if the platform and the BIOS support this feature.
624 Otherwise the 8254 will be used for timing services.
626 Choose N to continue using the legacy 8254 timer.
628 config HPET_EMULATE_RTC
630 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
632 # Mark as embedded because too many people got it wrong.
633 # The code disables itself when not needed.
636 bool "Enable DMI scanning" if EMBEDDED
638 Enabled scanning of DMI to identify machine quirks. Say Y
639 here unless you have verified that your setup is not
640 affected by entries in the DMI blacklist. Required by PNP
644 bool "GART IOMMU support" if EMBEDDED
647 depends on X86_64 && PCI
649 Support for full DMA access of devices with 32bit memory access only
650 on systems with more than 3GB. This is usually needed for USB,
651 sound, many IDE/SATA chipsets and some other devices.
652 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
653 based hardware IOMMU and a software bounce buffer based IOMMU used
654 on Intel systems and as fallback.
655 The code is only active when needed (enough memory and limited
656 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
660 bool "IBM Calgary IOMMU support"
662 depends on X86_64 && PCI && EXPERIMENTAL
664 Support for hardware IOMMUs in IBM's xSeries x366 and x460
665 systems. Needed to run systems with more than 3GB of memory
666 properly with 32-bit PCI devices that do not support DAC
667 (Double Address Cycle). Calgary also supports bus level
668 isolation, where all DMAs pass through the IOMMU. This
669 prevents them from going anywhere except their intended
670 destination. This catches hard-to-find kernel bugs and
671 mis-behaving drivers and devices that do not use the DMA-API
672 properly to set up their DMA buffers. The IOMMU can be
673 turned off at boot time with the iommu=off parameter.
674 Normally the kernel will make the right choice by itself.
677 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
679 prompt "Should Calgary be enabled by default?"
680 depends on CALGARY_IOMMU
682 Should Calgary be enabled by default? if you choose 'y', Calgary
683 will be used (if it exists). If you choose 'n', Calgary will not be
684 used even if it exists. If you choose 'n' and would like to use
685 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
689 bool "AMD IOMMU support"
692 depends on X86_64 && PCI && ACPI
694 With this option you can enable support for AMD IOMMU hardware in
695 your system. An IOMMU is a hardware component which provides
696 remapping of DMA memory accesses from devices. With an AMD IOMMU you
697 can isolate the the DMA memory of different devices and protect the
698 system from misbehaving device drivers or hardware.
700 You can find out if your system has an AMD IOMMU if you look into
701 your BIOS for an option to enable it or if you have an IVRS ACPI
704 config AMD_IOMMU_STATS
705 bool "Export AMD IOMMU statistics to debugfs"
709 This option enables code in the AMD IOMMU driver to collect various
710 statistics about whats happening in the driver and exports that
711 information to userspace via debugfs.
714 # need this always selected by IOMMU for the VIA workaround
718 Support for software bounce buffers used on x86-64 systems
719 which don't have a hardware IOMMU (e.g. the current generation
720 of Intel's x86-64 CPUs). Using this PCI devices which can only
721 access 32-bits of memory can be used on systems with more than
722 3 GB of memory. If unsure, say Y.
725 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
728 def_bool (AMD_IOMMU || DMAR)
731 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
732 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
733 select CPUMASK_OFFSTACK
736 Configure maximum number of CPUS and NUMA Nodes for this architecture.
740 int "Maximum number of CPUs" if SMP && !MAXSMP
741 range 2 8 if SMP && X86_32 && !X86_BIGSMP
742 range 2 512 if SMP && !MAXSMP
744 default "4096" if MAXSMP
745 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
748 This allows you to specify the maximum number of CPUs which this
749 kernel will support. The maximum supported value is 512 and the
750 minimum value which makes sense is 2.
752 This is purely to save memory - each supported CPU adds
753 approximately eight kilobytes to the kernel image.
756 bool "SMT (Hyperthreading) scheduler support"
759 SMT scheduler support improves the CPU scheduler's decision making
760 when dealing with Intel Pentium 4 chips with HyperThreading at a
761 cost of slightly increased overhead in some places. If unsure say
766 prompt "Multi-core scheduler support"
769 Multi-core scheduler support improves the CPU scheduler's decision
770 making when dealing with multi-core CPU chips at a cost of slightly
771 increased overhead in some places. If unsure say N here.
773 source "kernel/Kconfig.preempt"
776 bool "Local APIC support on uniprocessors"
777 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
779 A local APIC (Advanced Programmable Interrupt Controller) is an
780 integrated interrupt controller in the CPU. If you have a single-CPU
781 system which has a processor with a local APIC, you can say Y here to
782 enable and use it. If you say Y here even though your machine doesn't
783 have a local APIC, then the kernel will still run with no slowdown at
784 all. The local APIC supports CPU-generated self-interrupts (timer,
785 performance counters), and the NMI watchdog which detects hard
789 bool "IO-APIC support on uniprocessors"
790 depends on X86_UP_APIC
792 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
793 SMP-capable replacement for PC-style interrupt controllers. Most
794 SMP systems and many recent uniprocessor systems have one.
796 If you have a single-CPU system with an IO-APIC, you can say Y here
797 to use it. If you say Y here even though your machine doesn't have
798 an IO-APIC, then the kernel will still run with no slowdown at all.
800 config X86_LOCAL_APIC
802 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
806 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
808 config X86_VISWS_APIC
810 depends on X86_32 && X86_VISWS
812 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
813 bool "Reroute for broken boot IRQs"
815 depends on X86_IO_APIC
817 This option enables a workaround that fixes a source of
818 spurious interrupts. This is recommended when threaded
819 interrupt handling is used on systems where the generation of
820 superfluous "boot interrupts" cannot be disabled.
822 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
823 entry in the chipset's IO-APIC is masked (as, e.g. the RT
824 kernel does during interrupt handling). On chipsets where this
825 boot IRQ generation cannot be disabled, this workaround keeps
826 the original IRQ line masked so that only the equivalent "boot
827 IRQ" is delivered to the CPUs. The workaround also tells the
828 kernel to set up the IRQ handler on the boot IRQ line. In this
829 way only one interrupt is delivered to the kernel. Otherwise
830 the spurious second interrupt may cause the kernel to bring
831 down (vital) interrupt lines.
833 Only affects "broken" chipsets. Interrupt sharing may be
834 increased on these systems.
837 bool "Machine Check / overheating reporting"
839 Machine Check support allows the processor to notify the
840 kernel if it detects a problem (e.g. overheating, data corruption).
841 The action the kernel takes depends on the severity of the problem,
842 ranging from warning messages to halting the machine.
846 prompt "Intel MCE features"
847 depends on X86_MCE && X86_LOCAL_APIC
849 Additional support for intel specific MCE features such as
854 prompt "AMD MCE features"
855 depends on X86_MCE && X86_LOCAL_APIC
857 Additional support for AMD specific MCE features such as
858 the DRAM Error Threshold.
860 config X86_ANCIENT_MCE
862 depends on X86_32 && X86_MCE
863 prompt "Support for old Pentium 5 / WinChip machine checks"
865 Include support for machine check handling on old Pentium 5 or WinChip
866 systems. These typically need to be enabled explicitely on the command
869 config X86_MCE_THRESHOLD
870 depends on X86_MCE_AMD || X86_MCE_INTEL
874 config X86_MCE_INJECT
876 tristate "Machine check injector support"
878 Provide support for injecting machine checks for testing purposes.
879 If you don't know what a machine check is and you don't do kernel
880 QA it is safe to say n.
882 config X86_THERMAL_VECTOR
884 depends on X86_MCE_INTEL
887 bool "Enable VM86 support" if EMBEDDED
891 This option is required by programs like DOSEMU to run 16-bit legacy
892 code on X86 processors. It also may be needed by software like
893 XFree86 to initialize some video cards via BIOS. Disabling this
894 option saves about 6k.
897 tristate "Toshiba Laptop support"
900 This adds a driver to safely access the System Management Mode of
901 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
902 not work on models with a Phoenix BIOS. The System Management Mode
903 is used to set the BIOS and power saving options on Toshiba portables.
905 For information on utilities to make use of this driver see the
906 Toshiba Linux utilities web site at:
907 <http://www.buzzard.org.uk/toshiba/>.
909 Say Y if you intend to run this kernel on a Toshiba portable.
913 tristate "Dell laptop support"
915 This adds a driver to safely access the System Management Mode
916 of the CPU on the Dell Inspiron 8000. The System Management Mode
917 is used to read cpu temperature and cooling fan status and to
918 control the fans on the I8K portables.
920 This driver has been tested only on the Inspiron 8000 but it may
921 also work with other Dell laptops. You can force loading on other
922 models by passing the parameter `force=1' to the module. Use at
925 For information on utilities to make use of this driver see the
926 I8K Linux utilities web site at:
927 <http://people.debian.org/~dz/i8k/>
929 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
932 config X86_REBOOTFIXUPS
933 bool "Enable X86 board specific fixups for reboot"
936 This enables chipset and/or board specific fixups to be done
937 in order to get reboot to work correctly. This is only needed on
938 some combinations of hardware and BIOS. The symptom, for which
939 this config is intended, is when reboot ends with a stalled/hung
942 Currently, the only fixup is for the Geode machines using
943 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
945 Say Y if you want to enable the fixup. Currently, it's safe to
946 enable this option even if you don't need it.
950 tristate "/dev/cpu/microcode - microcode support"
953 If you say Y here, you will be able to update the microcode on
954 certain Intel and AMD processors. The Intel support is for the
955 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
956 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
957 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
958 You will obviously need the actual microcode binary data itself
959 which is not shipped with the Linux kernel.
961 This option selects the general module only, you need to select
962 at least one vendor specific module as well.
964 To compile this driver as a module, choose M here: the
965 module will be called microcode.
967 config MICROCODE_INTEL
968 bool "Intel microcode patch loading support"
973 This options enables microcode patch loading support for Intel
976 For latest news and information on obtaining all the required
977 Intel ingredients for this driver, check:
978 <http://www.urbanmyth.org/microcode/>.
981 bool "AMD microcode patch loading support"
985 If you select this option, microcode patch loading support for AMD
986 processors will be enabled.
988 config MICROCODE_OLD_INTERFACE
993 tristate "/dev/cpu/*/msr - Model-specific register support"
995 This device gives privileged processes access to the x86
996 Model-Specific Registers (MSRs). It is a character device with
997 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
998 MSR accesses are directed to a specific CPU on multi-processor
1002 tristate "/dev/cpu/*/cpuid - CPU information support"
1004 This device gives processes access to the x86 CPUID instruction to
1005 be executed on a specific processor. It is a character device
1006 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1010 prompt "High Memory Support"
1011 default HIGHMEM4G if !X86_NUMAQ
1012 default HIGHMEM64G if X86_NUMAQ
1017 depends on !X86_NUMAQ
1019 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1020 However, the address space of 32-bit x86 processors is only 4
1021 Gigabytes large. That means that, if you have a large amount of
1022 physical memory, not all of it can be "permanently mapped" by the
1023 kernel. The physical memory that's not permanently mapped is called
1026 If you are compiling a kernel which will never run on a machine with
1027 more than 1 Gigabyte total physical RAM, answer "off" here (default
1028 choice and suitable for most users). This will result in a "3GB/1GB"
1029 split: 3GB are mapped so that each process sees a 3GB virtual memory
1030 space and the remaining part of the 4GB virtual memory space is used
1031 by the kernel to permanently map as much physical memory as
1034 If the machine has between 1 and 4 Gigabytes physical RAM, then
1037 If more than 4 Gigabytes is used then answer "64GB" here. This
1038 selection turns Intel PAE (Physical Address Extension) mode on.
1039 PAE implements 3-level paging on IA32 processors. PAE is fully
1040 supported by Linux, PAE mode is implemented on all recent Intel
1041 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1042 then the kernel will not boot on CPUs that don't support PAE!
1044 The actual amount of total physical memory will either be
1045 auto detected or can be forced by using a kernel command line option
1046 such as "mem=256M". (Try "man bootparam" or see the documentation of
1047 your boot loader (lilo or loadlin) about how to pass options to the
1048 kernel at boot time.)
1050 If unsure, say "off".
1054 depends on !X86_NUMAQ
1056 Select this if you have a 32-bit processor and between 1 and 4
1057 gigabytes of physical RAM.
1061 depends on !M386 && !M486
1064 Select this if you have a 32-bit processor and more than 4
1065 gigabytes of physical RAM.
1070 depends on EXPERIMENTAL
1071 prompt "Memory split" if EMBEDDED
1075 Select the desired split between kernel and user memory.
1077 If the address range available to the kernel is less than the
1078 physical memory installed, the remaining memory will be available
1079 as "high memory". Accessing high memory is a little more costly
1080 than low memory, as it needs to be mapped into the kernel first.
1081 Note that increasing the kernel address space limits the range
1082 available to user programs, making the address space there
1083 tighter. Selecting anything other than the default 3G/1G split
1084 will also likely make your kernel incompatible with binary-only
1087 If you are not absolutely sure what you are doing, leave this
1091 bool "3G/1G user/kernel split"
1092 config VMSPLIT_3G_OPT
1094 bool "3G/1G user/kernel split (for full 1G low memory)"
1096 bool "2G/2G user/kernel split"
1097 config VMSPLIT_2G_OPT
1099 bool "2G/2G user/kernel split (for full 2G low memory)"
1101 bool "1G/3G user/kernel split"
1106 default 0xB0000000 if VMSPLIT_3G_OPT
1107 default 0x80000000 if VMSPLIT_2G
1108 default 0x78000000 if VMSPLIT_2G_OPT
1109 default 0x40000000 if VMSPLIT_1G
1115 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1118 bool "PAE (Physical Address Extension) Support"
1119 depends on X86_32 && !HIGHMEM4G
1121 PAE is required for NX support, and furthermore enables
1122 larger swapspace support for non-overcommit purposes. It
1123 has the cost of more pagetable lookup overhead, and also
1124 consumes more pagetable space per process.
1126 config ARCH_PHYS_ADDR_T_64BIT
1127 def_bool X86_64 || X86_PAE
1129 config DIRECT_GBPAGES
1130 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1134 Allow the kernel linear mapping to use 1GB pages on CPUs that
1135 support it. This can improve the kernel's performance a tiny bit by
1136 reducing TLB pressure. If in doubt, say "Y".
1138 # Common NUMA Features
1140 bool "Numa Memory Allocation and Scheduler Support"
1142 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1143 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1145 Enable NUMA (Non Uniform Memory Access) support.
1147 The kernel will try to allocate memory used by a CPU on the
1148 local memory controller of the CPU and add some more
1149 NUMA awareness to the kernel.
1151 For 64-bit this is recommended if the system is Intel Core i7
1152 (or later), AMD Opteron, or EM64T NUMA.
1154 For 32-bit this is only needed on (rare) 32-bit-only platforms
1155 that support NUMA topologies, such as NUMAQ / Summit, or if you
1156 boot a 32-bit kernel on a 64-bit NUMA platform.
1158 Otherwise, you should say N.
1160 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1161 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1165 prompt "Old style AMD Opteron NUMA detection"
1166 depends on X86_64 && NUMA && PCI
1168 Enable K8 NUMA node topology detection. You should say Y here if
1169 you have a multi processor AMD K8 system. This uses an old
1170 method to read the NUMA configuration directly from the builtin
1171 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1172 instead, which also takes priority if both are compiled in.
1174 config X86_64_ACPI_NUMA
1176 prompt "ACPI NUMA detection"
1177 depends on X86_64 && NUMA && ACPI && PCI
1180 Enable ACPI SRAT based node topology detection.
1182 # Some NUMA nodes have memory ranges that span
1183 # other nodes. Even though a pfn is valid and
1184 # between a node's start and end pfns, it may not
1185 # reside on that node. See memmap_init_zone()
1187 config NODES_SPAN_OTHER_NODES
1189 depends on X86_64_ACPI_NUMA
1192 bool "NUMA emulation"
1193 depends on X86_64 && NUMA
1195 Enable NUMA emulation. A flat machine will be split
1196 into virtual nodes when booted with "numa=fake=N", where N is the
1197 number of nodes. This is only useful for debugging.
1200 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1202 default "9" if MAXSMP
1203 default "6" if X86_64
1204 default "4" if X86_NUMAQ
1206 depends on NEED_MULTIPLE_NODES
1208 Specify the maximum number of NUMA Nodes available on the target
1209 system. Increases memory reserved to accommodate various tables.
1211 config HAVE_ARCH_BOOTMEM
1213 depends on X86_32 && NUMA
1215 config ARCH_HAVE_MEMORY_PRESENT
1217 depends on X86_32 && DISCONTIGMEM
1219 config NEED_NODE_MEMMAP_SIZE
1221 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1223 config HAVE_ARCH_ALLOC_REMAP
1225 depends on X86_32 && NUMA
1227 config ARCH_FLATMEM_ENABLE
1229 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1231 config ARCH_DISCONTIGMEM_ENABLE
1233 depends on NUMA && X86_32
1235 config ARCH_DISCONTIGMEM_DEFAULT
1237 depends on NUMA && X86_32
1239 config ARCH_PROC_KCORE_TEXT
1241 depends on X86_64 && PROC_KCORE
1243 config ARCH_SPARSEMEM_DEFAULT
1247 config ARCH_SPARSEMEM_ENABLE
1249 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1250 select SPARSEMEM_STATIC if X86_32
1251 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1253 config ARCH_SELECT_MEMORY_MODEL
1255 depends on ARCH_SPARSEMEM_ENABLE
1257 config ARCH_MEMORY_PROBE
1259 depends on MEMORY_HOTPLUG
1261 config ILLEGAL_POINTER_VALUE
1264 default 0xdead000000000000 if X86_64
1269 bool "Allocate 3rd-level pagetables from highmem"
1270 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1272 The VM uses one page table entry for each page of physical memory.
1273 For systems with a lot of RAM, this can be wasteful of precious
1274 low memory. Setting this option will put user-space page table
1275 entries in high memory.
1277 config X86_CHECK_BIOS_CORRUPTION
1278 bool "Check for low memory corruption"
1280 Periodically check for memory corruption in low memory, which
1281 is suspected to be caused by BIOS. Even when enabled in the
1282 configuration, it is disabled at runtime. Enable it by
1283 setting "memory_corruption_check=1" on the kernel command
1284 line. By default it scans the low 64k of memory every 60
1285 seconds; see the memory_corruption_check_size and
1286 memory_corruption_check_period parameters in
1287 Documentation/kernel-parameters.txt to adjust this.
1289 When enabled with the default parameters, this option has
1290 almost no overhead, as it reserves a relatively small amount
1291 of memory and scans it infrequently. It both detects corruption
1292 and prevents it from affecting the running system.
1294 It is, however, intended as a diagnostic tool; if repeatable
1295 BIOS-originated corruption always affects the same memory,
1296 you can use memmap= to prevent the kernel from using that
1299 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1300 bool "Set the default setting of memory_corruption_check"
1301 depends on X86_CHECK_BIOS_CORRUPTION
1304 Set whether the default state of memory_corruption_check is
1307 config X86_RESERVE_LOW_64K
1308 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1311 Reserve the first 64K of physical RAM on BIOSes that are known
1312 to potentially corrupt that memory range. A numbers of BIOSes are
1313 known to utilize this area during suspend/resume, so it must not
1314 be used by the kernel.
1316 Set this to N if you are absolutely sure that you trust the BIOS
1317 to get all its memory reservations and usages right.
1319 If you have doubts about the BIOS (e.g. suspend/resume does not
1320 work or there's kernel crashes after certain hardware hotplug
1321 events) and it's not AMI or Phoenix, then you might want to enable
1322 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1323 corruption patterns.
1327 config MATH_EMULATION
1329 prompt "Math emulation" if X86_32
1331 Linux can emulate a math coprocessor (used for floating point
1332 operations) if you don't have one. 486DX and Pentium processors have
1333 a math coprocessor built in, 486SX and 386 do not, unless you added
1334 a 487DX or 387, respectively. (The messages during boot time can
1335 give you some hints here ["man dmesg"].) Everyone needs either a
1336 coprocessor or this emulation.
1338 If you don't have a math coprocessor, you need to say Y here; if you
1339 say Y here even though you have a coprocessor, the coprocessor will
1340 be used nevertheless. (This behavior can be changed with the kernel
1341 command line option "no387", which comes handy if your coprocessor
1342 is broken. Try "man bootparam" or see the documentation of your boot
1343 loader (lilo or loadlin) about how to pass options to the kernel at
1344 boot time.) This means that it is a good idea to say Y here if you
1345 intend to use this kernel on different machines.
1347 More information about the internals of the Linux math coprocessor
1348 emulation can be found in <file:arch/x86/math-emu/README>.
1350 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1351 kernel, it won't hurt.
1356 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1358 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1359 the Memory Type Range Registers (MTRRs) may be used to control
1360 processor access to memory ranges. This is most useful if you have
1361 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1362 allows bus write transfers to be combined into a larger transfer
1363 before bursting over the PCI/AGP bus. This can increase performance
1364 of image write operations 2.5 times or more. Saying Y here creates a
1365 /proc/mtrr file which may be used to manipulate your processor's
1366 MTRRs. Typically the X server should use this.
1368 This code has a reasonably generic interface so that similar
1369 control registers on other processors can be easily supported
1372 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1373 Registers (ARRs) which provide a similar functionality to MTRRs. For
1374 these, the ARRs are used to emulate the MTRRs.
1375 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1376 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1377 write-combining. All of these processors are supported by this code
1378 and it makes sense to say Y here if you have one of them.
1380 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1381 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1382 can lead to all sorts of problems, so it's good to say Y here.
1384 You can safely say Y even if your machine doesn't have MTRRs, you'll
1385 just add about 9 KB to your kernel.
1387 See <file:Documentation/x86/mtrr.txt> for more information.
1389 config MTRR_SANITIZER
1391 prompt "MTRR cleanup support"
1394 Convert MTRR layout from continuous to discrete, so X drivers can
1395 add writeback entries.
1397 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1398 The largest mtrr entry size for a continuous block can be set with
1403 config MTRR_SANITIZER_ENABLE_DEFAULT
1404 int "MTRR cleanup enable value (0-1)"
1407 depends on MTRR_SANITIZER
1409 Enable mtrr cleanup default value
1411 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1412 int "MTRR cleanup spare reg num (0-7)"
1415 depends on MTRR_SANITIZER
1417 mtrr cleanup spare entries default, it can be changed via
1418 mtrr_spare_reg_nr=N on the kernel command line.
1423 prompt "x86 PAT support" if EMBEDDED
1426 Use PAT attributes to setup page level cache control.
1428 PATs are the modern equivalents of MTRRs and are much more
1429 flexible than MTRRs.
1431 Say N here if you see bootup problems (boot crash, boot hang,
1432 spontaneous reboots) or a non-working video driver.
1436 config ARCH_USES_PG_UNCACHED
1441 bool "EFI runtime service support"
1444 This enables the kernel to use EFI runtime services that are
1445 available (such as the EFI variable services).
1447 This option is only useful on systems that have EFI firmware.
1448 In addition, you should use the latest ELILO loader available
1449 at <http://elilo.sourceforge.net> in order to take advantage
1450 of EFI runtime services. However, even with this option, the
1451 resultant kernel should continue to boot on existing non-EFI
1456 prompt "Enable seccomp to safely compute untrusted bytecode"
1458 This kernel feature is useful for number crunching applications
1459 that may need to compute untrusted bytecode during their
1460 execution. By using pipes or other transports made available to
1461 the process as file descriptors supporting the read/write
1462 syscalls, it's possible to isolate those applications in
1463 their own address space using seccomp. Once seccomp is
1464 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1465 and the task is only allowed to execute a few safe syscalls
1466 defined by each seccomp mode.
1468 If unsure, say Y. Only embedded should say N here.
1470 config CC_STACKPROTECTOR
1471 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1473 This option turns on the -fstack-protector GCC feature. This
1474 feature puts, at the beginning of functions, a canary value on
1475 the stack just before the return address, and validates
1476 the value just before actually returning. Stack based buffer
1477 overflows (that need to overwrite this return address) now also
1478 overwrite the canary, which gets detected and the attack is then
1479 neutralized via a kernel panic.
1481 This feature requires gcc version 4.2 or above, or a distribution
1482 gcc with the feature backported. Older versions are automatically
1483 detected and for those versions, this configuration option is
1484 ignored. (and a warning is printed during bootup)
1486 source kernel/Kconfig.hz
1489 bool "kexec system call"
1491 kexec is a system call that implements the ability to shutdown your
1492 current kernel, and to start another kernel. It is like a reboot
1493 but it is independent of the system firmware. And like a reboot
1494 you can start any kernel with it, not just Linux.
1496 The name comes from the similarity to the exec system call.
1498 It is an ongoing process to be certain the hardware in a machine
1499 is properly shutdown, so do not be surprised if this code does not
1500 initially work for you. It may help to enable device hotplugging
1501 support. As of this writing the exact hardware interface is
1502 strongly in flux, so no good recommendation can be made.
1505 bool "kernel crash dumps"
1506 depends on X86_64 || (X86_32 && HIGHMEM)
1508 Generate crash dump after being started by kexec.
1509 This should be normally only set in special crash dump kernels
1510 which are loaded in the main kernel with kexec-tools into
1511 a specially reserved region and then later executed after
1512 a crash by kdump/kexec. The crash dump kernel must be compiled
1513 to a memory address not used by the main kernel or BIOS using
1514 PHYSICAL_START, or it must be built as a relocatable image
1515 (CONFIG_RELOCATABLE=y).
1516 For more details see Documentation/kdump/kdump.txt
1519 bool "kexec jump (EXPERIMENTAL)"
1520 depends on EXPERIMENTAL
1521 depends on KEXEC && HIBERNATION
1523 Jump between original kernel and kexeced kernel and invoke
1524 code in physical address mode via KEXEC
1526 config PHYSICAL_START
1527 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1530 This gives the physical address where the kernel is loaded.
1532 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1533 bzImage will decompress itself to above physical address and
1534 run from there. Otherwise, bzImage will run from the address where
1535 it has been loaded by the boot loader and will ignore above physical
1538 In normal kdump cases one does not have to set/change this option
1539 as now bzImage can be compiled as a completely relocatable image
1540 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1541 address. This option is mainly useful for the folks who don't want
1542 to use a bzImage for capturing the crash dump and want to use a
1543 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1544 to be specifically compiled to run from a specific memory area
1545 (normally a reserved region) and this option comes handy.
1547 So if you are using bzImage for capturing the crash dump,
1548 leave the value here unchanged to 0x1000000 and set
1549 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1550 for capturing the crash dump change this value to start of
1551 the reserved region. In other words, it can be set based on
1552 the "X" value as specified in the "crashkernel=YM@XM"
1553 command line boot parameter passed to the panic-ed
1554 kernel. Please take a look at Documentation/kdump/kdump.txt
1555 for more details about crash dumps.
1557 Usage of bzImage for capturing the crash dump is recommended as
1558 one does not have to build two kernels. Same kernel can be used
1559 as production kernel and capture kernel. Above option should have
1560 gone away after relocatable bzImage support is introduced. But it
1561 is present because there are users out there who continue to use
1562 vmlinux for dump capture. This option should go away down the
1565 Don't change this unless you know what you are doing.
1568 bool "Build a relocatable kernel"
1571 This builds a kernel image that retains relocation information
1572 so it can be loaded someplace besides the default 1MB.
1573 The relocations tend to make the kernel binary about 10% larger,
1574 but are discarded at runtime.
1576 One use is for the kexec on panic case where the recovery kernel
1577 must live at a different physical address than the primary
1580 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1581 it has been loaded at and the compile time physical address
1582 (CONFIG_PHYSICAL_START) is ignored.
1584 # Relocation on x86-32 needs some additional build support
1585 config X86_NEED_RELOCS
1587 depends on X86_32 && RELOCATABLE
1589 config PHYSICAL_ALIGN
1591 prompt "Alignment value to which kernel should be aligned" if X86_32
1593 range 0x2000 0x1000000
1595 This value puts the alignment restrictions on physical address
1596 where kernel is loaded and run from. Kernel is compiled for an
1597 address which meets above alignment restriction.
1599 If bootloader loads the kernel at a non-aligned address and
1600 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1601 address aligned to above value and run from there.
1603 If bootloader loads the kernel at a non-aligned address and
1604 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1605 load address and decompress itself to the address it has been
1606 compiled for and run from there. The address for which kernel is
1607 compiled already meets above alignment restrictions. Hence the
1608 end result is that kernel runs from a physical address meeting
1609 above alignment restrictions.
1611 Don't change this unless you know what you are doing.
1614 bool "Support for hot-pluggable CPUs"
1615 depends on SMP && HOTPLUG
1617 Say Y here to allow turning CPUs off and on. CPUs can be
1618 controlled through /sys/devices/system/cpu.
1619 ( Note: power management support will enable this option
1620 automatically on SMP systems. )
1621 Say N if you want to disable CPU hotplug.
1625 prompt "Compat VDSO support"
1626 depends on X86_32 || IA32_EMULATION
1628 Map the 32-bit VDSO to the predictable old-style address too.
1630 Say N here if you are running a sufficiently recent glibc
1631 version (2.3.3 or later), to remove the high-mapped
1632 VDSO mapping and to exclusively use the randomized VDSO.
1637 bool "Built-in kernel command line"
1640 Allow for specifying boot arguments to the kernel at
1641 build time. On some systems (e.g. embedded ones), it is
1642 necessary or convenient to provide some or all of the
1643 kernel boot arguments with the kernel itself (that is,
1644 to not rely on the boot loader to provide them.)
1646 To compile command line arguments into the kernel,
1647 set this option to 'Y', then fill in the
1648 the boot arguments in CONFIG_CMDLINE.
1650 Systems with fully functional boot loaders (i.e. non-embedded)
1651 should leave this option set to 'N'.
1654 string "Built-in kernel command string"
1655 depends on CMDLINE_BOOL
1658 Enter arguments here that should be compiled into the kernel
1659 image and used at boot time. If the boot loader provides a
1660 command line at boot time, it is appended to this string to
1661 form the full kernel command line, when the system boots.
1663 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1664 change this behavior.
1666 In most cases, the command line (whether built-in or provided
1667 by the boot loader) should specify the device for the root
1670 config CMDLINE_OVERRIDE
1671 bool "Built-in command line overrides boot loader arguments"
1673 depends on CMDLINE_BOOL
1675 Set this option to 'Y' to have the kernel ignore the boot loader
1676 command line, and use ONLY the built-in command line.
1678 This is used to work around broken boot loaders. This should
1679 be set to 'N' under normal conditions.
1683 config ARCH_ENABLE_MEMORY_HOTPLUG
1685 depends on X86_64 || (X86_32 && HIGHMEM)
1687 config ARCH_ENABLE_MEMORY_HOTREMOVE
1689 depends on MEMORY_HOTPLUG
1691 config HAVE_ARCH_EARLY_PFN_TO_NID
1695 menu "Power management and ACPI options"
1697 config ARCH_HIBERNATION_HEADER
1699 depends on X86_64 && HIBERNATION
1701 source "kernel/power/Kconfig"
1703 source "drivers/acpi/Kconfig"
1705 source "drivers/sfi/Kconfig"
1710 depends on APM || APM_MODULE
1713 tristate "APM (Advanced Power Management) BIOS support"
1714 depends on X86_32 && PM_SLEEP
1716 APM is a BIOS specification for saving power using several different
1717 techniques. This is mostly useful for battery powered laptops with
1718 APM compliant BIOSes. If you say Y here, the system time will be
1719 reset after a RESUME operation, the /proc/apm device will provide
1720 battery status information, and user-space programs will receive
1721 notification of APM "events" (e.g. battery status change).
1723 If you select "Y" here, you can disable actual use of the APM
1724 BIOS by passing the "apm=off" option to the kernel at boot time.
1726 Note that the APM support is almost completely disabled for
1727 machines with more than one CPU.
1729 In order to use APM, you will need supporting software. For location
1730 and more information, read <file:Documentation/power/pm.txt> and the
1731 Battery Powered Linux mini-HOWTO, available from
1732 <http://www.tldp.org/docs.html#howto>.
1734 This driver does not spin down disk drives (see the hdparm(8)
1735 manpage ("man 8 hdparm") for that), and it doesn't turn off
1736 VESA-compliant "green" monitors.
1738 This driver does not support the TI 4000M TravelMate and the ACER
1739 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1740 desktop machines also don't have compliant BIOSes, and this driver
1741 may cause those machines to panic during the boot phase.
1743 Generally, if you don't have a battery in your machine, there isn't
1744 much point in using this driver and you should say N. If you get
1745 random kernel OOPSes or reboots that don't seem to be related to
1746 anything, try disabling/enabling this option (or disabling/enabling
1749 Some other things you should try when experiencing seemingly random,
1752 1) make sure that you have enough swap space and that it is
1754 2) pass the "no-hlt" option to the kernel
1755 3) switch on floating point emulation in the kernel and pass
1756 the "no387" option to the kernel
1757 4) pass the "floppy=nodma" option to the kernel
1758 5) pass the "mem=4M" option to the kernel (thereby disabling
1759 all but the first 4 MB of RAM)
1760 6) make sure that the CPU is not over clocked.
1761 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1762 8) disable the cache from your BIOS settings
1763 9) install a fan for the video card or exchange video RAM
1764 10) install a better fan for the CPU
1765 11) exchange RAM chips
1766 12) exchange the motherboard.
1768 To compile this driver as a module, choose M here: the
1769 module will be called apm.
1773 config APM_IGNORE_USER_SUSPEND
1774 bool "Ignore USER SUSPEND"
1776 This option will ignore USER SUSPEND requests. On machines with a
1777 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1778 series notebooks, it is necessary to say Y because of a BIOS bug.
1780 config APM_DO_ENABLE
1781 bool "Enable PM at boot time"
1783 Enable APM features at boot time. From page 36 of the APM BIOS
1784 specification: "When disabled, the APM BIOS does not automatically
1785 power manage devices, enter the Standby State, enter the Suspend
1786 State, or take power saving steps in response to CPU Idle calls."
1787 This driver will make CPU Idle calls when Linux is idle (unless this
1788 feature is turned off -- see "Do CPU IDLE calls", below). This
1789 should always save battery power, but more complicated APM features
1790 will be dependent on your BIOS implementation. You may need to turn
1791 this option off if your computer hangs at boot time when using APM
1792 support, or if it beeps continuously instead of suspending. Turn
1793 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1794 T400CDT. This is off by default since most machines do fine without
1798 bool "Make CPU Idle calls when idle"
1800 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1801 On some machines, this can activate improved power savings, such as
1802 a slowed CPU clock rate, when the machine is idle. These idle calls
1803 are made after the idle loop has run for some length of time (e.g.,
1804 333 mS). On some machines, this will cause a hang at boot time or
1805 whenever the CPU becomes idle. (On machines with more than one CPU,
1806 this option does nothing.)
1808 config APM_DISPLAY_BLANK
1809 bool "Enable console blanking using APM"
1811 Enable console blanking using the APM. Some laptops can use this to
1812 turn off the LCD backlight when the screen blanker of the Linux
1813 virtual console blanks the screen. Note that this is only used by
1814 the virtual console screen blanker, and won't turn off the backlight
1815 when using the X Window system. This also doesn't have anything to
1816 do with your VESA-compliant power-saving monitor. Further, this
1817 option doesn't work for all laptops -- it might not turn off your
1818 backlight at all, or it might print a lot of errors to the console,
1819 especially if you are using gpm.
1821 config APM_ALLOW_INTS
1822 bool "Allow interrupts during APM BIOS calls"
1824 Normally we disable external interrupts while we are making calls to
1825 the APM BIOS as a measure to lessen the effects of a badly behaving
1826 BIOS implementation. The BIOS should reenable interrupts if it
1827 needs to. Unfortunately, some BIOSes do not -- especially those in
1828 many of the newer IBM Thinkpads. If you experience hangs when you
1829 suspend, try setting this to Y. Otherwise, say N.
1833 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1835 source "drivers/cpuidle/Kconfig"
1837 source "drivers/idle/Kconfig"
1842 menu "Bus options (PCI etc.)"
1847 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1849 Find out whether you have a PCI motherboard. PCI is the name of a
1850 bus system, i.e. the way the CPU talks to the other stuff inside
1851 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1852 VESA. If you have PCI, say Y, otherwise N.
1855 prompt "PCI access mode"
1856 depends on X86_32 && PCI
1859 On PCI systems, the BIOS can be used to detect the PCI devices and
1860 determine their configuration. However, some old PCI motherboards
1861 have BIOS bugs and may crash if this is done. Also, some embedded
1862 PCI-based systems don't have any BIOS at all. Linux can also try to
1863 detect the PCI hardware directly without using the BIOS.
1865 With this option, you can specify how Linux should detect the
1866 PCI devices. If you choose "BIOS", the BIOS will be used,
1867 if you choose "Direct", the BIOS won't be used, and if you
1868 choose "MMConfig", then PCI Express MMCONFIG will be used.
1869 If you choose "Any", the kernel will try MMCONFIG, then the
1870 direct access method and falls back to the BIOS if that doesn't
1871 work. If unsure, go with the default, which is "Any".
1876 config PCI_GOMMCONFIG
1893 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1895 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1898 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1902 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1906 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1913 bool "Support mmconfig PCI config space access"
1914 depends on X86_64 && PCI && ACPI
1917 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1918 depends on PCI_MSI && ACPI && EXPERIMENTAL
1920 DMA remapping (DMAR) devices support enables independent address
1921 translations for Direct Memory Access (DMA) from devices.
1922 These DMA remapping devices are reported via ACPI tables
1923 and include PCI device scope covered by these DMA
1926 config DMAR_DEFAULT_ON
1928 prompt "Enable DMA Remapping Devices by default"
1931 Selecting this option will enable a DMAR device at boot time if
1932 one is found. If this option is not selected, DMAR support can
1933 be enabled by passing intel_iommu=on to the kernel. It is
1934 recommended you say N here while the DMAR code remains
1937 config DMAR_BROKEN_GFX_WA
1939 prompt "Workaround broken graphics drivers (going away soon)"
1940 depends on DMAR && BROKEN
1942 Current Graphics drivers tend to use physical address
1943 for DMA and avoid using DMA APIs. Setting this config
1944 option permits the IOMMU driver to set a unity map for
1945 all the OS-visible memory. Hence the driver can continue
1946 to use physical addresses for DMA, at least until this
1947 option is removed in the 2.6.32 kernel.
1949 config DMAR_FLOPPY_WA
1953 Floppy disk drivers are known to bypass DMA API calls
1954 thereby failing to work when IOMMU is enabled. This
1955 workaround will setup a 1:1 mapping for the first
1956 16MiB to make floppy (an ISA device) work.
1959 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1960 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1962 Supports Interrupt remapping for IO-APIC and MSI devices.
1963 To use x2apic mode in the CPU's which support x2APIC enhancements or
1964 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1966 source "drivers/pci/pcie/Kconfig"
1968 source "drivers/pci/Kconfig"
1970 # x86_64 have no ISA slots, but do have ISA-style DMA.
1979 Find out whether you have ISA slots on your motherboard. ISA is the
1980 name of a bus system, i.e. the way the CPU talks to the other stuff
1981 inside your box. Other bus systems are PCI, EISA, MicroChannel
1982 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1983 newer boards don't support it. If you have ISA, say Y, otherwise N.
1989 The Extended Industry Standard Architecture (EISA) bus was
1990 developed as an open alternative to the IBM MicroChannel bus.
1992 The EISA bus provided some of the features of the IBM MicroChannel
1993 bus while maintaining backward compatibility with cards made for
1994 the older ISA bus. The EISA bus saw limited use between 1988 and
1995 1995 when it was made obsolete by the PCI bus.
1997 Say Y here if you are building a kernel for an EISA-based machine.
2001 source "drivers/eisa/Kconfig"
2006 MicroChannel Architecture is found in some IBM PS/2 machines and
2007 laptops. It is a bus system similar to PCI or ISA. See
2008 <file:Documentation/mca.txt> (and especially the web page given
2009 there) before attempting to build an MCA bus kernel.
2011 source "drivers/mca/Kconfig"
2014 tristate "NatSemi SCx200 support"
2016 This provides basic support for National Semiconductor's
2017 (now AMD's) Geode processors. The driver probes for the
2018 PCI-IDs of several on-chip devices, so its a good dependency
2019 for other scx200_* drivers.
2021 If compiled as a module, the driver is named scx200.
2023 config SCx200HR_TIMER
2024 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2025 depends on SCx200 && GENERIC_TIME
2028 This driver provides a clocksource built upon the on-chip
2029 27MHz high-resolution timer. Its also a workaround for
2030 NSC Geode SC-1100's buggy TSC, which loses time when the
2031 processor goes idle (as is done by the scheduler). The
2032 other workaround is idle=poll boot option.
2035 bool "One Laptop Per Child support"
2039 Add support for detecting the unique features of the OLPC
2046 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2048 source "drivers/pcmcia/Kconfig"
2050 source "drivers/pci/hotplug/Kconfig"
2055 menu "Executable file formats / Emulations"
2057 source "fs/Kconfig.binfmt"
2059 config IA32_EMULATION
2060 bool "IA32 Emulation"
2062 select COMPAT_BINFMT_ELF
2064 Include code to run 32-bit programs under a 64-bit kernel. You should
2065 likely turn this on, unless you're 100% sure that you don't have any
2066 32-bit programs left.
2069 tristate "IA32 a.out support"
2070 depends on IA32_EMULATION
2072 Support old a.out binaries in the 32bit emulation.
2076 depends on IA32_EMULATION
2078 config COMPAT_FOR_U64_ALIGNMENT
2082 config SYSVIPC_COMPAT
2084 depends on COMPAT && SYSVIPC
2089 config HAVE_ATOMIC_IOMAP
2093 source "net/Kconfig"
2095 source "drivers/Kconfig"
2097 source "drivers/firmware/Kconfig"
2101 source "arch/x86/Kconfig.debug"
2103 source "security/Kconfig"
2105 source "crypto/Kconfig"
2107 source "arch/x86/kvm/Kconfig"
2109 source "lib/Kconfig"