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
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_SYSCALL_TRACEPOINTS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_DMA_API_DEBUG
49 select HAVE_KERNEL_GZIP
50 select HAVE_KERNEL_BZIP2
51 select HAVE_KERNEL_LZMA
52 select HAVE_KERNEL_LZO
53 select HAVE_HW_BREAKPOINT
56 select HAVE_ARCH_KMEMCHECK
57 select HAVE_USER_RETURN_NOTIFIER
61 default "elf32-i386" if X86_32
62 default "elf64-x86-64" if X86_64
66 default "arch/x86/configs/i386_defconfig" if X86_32
67 default "arch/x86/configs/x86_64_defconfig" if X86_64
72 config GENERIC_CMOS_UPDATE
75 config CLOCKSOURCE_WATCHDOG
78 config GENERIC_CLOCKEVENTS
81 config GENERIC_CLOCKEVENTS_BROADCAST
83 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
85 config LOCKDEP_SUPPORT
88 config STACKTRACE_SUPPORT
91 config HAVE_LATENCYTOP_SUPPORT
103 config GENERIC_ISA_DMA
112 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
114 config GENERIC_BUG_RELATIVE_POINTERS
117 config GENERIC_HWEIGHT
123 config ARCH_MAY_HAVE_PC_FDC
126 config RWSEM_GENERIC_SPINLOCK
129 config RWSEM_XCHGADD_ALGORITHM
132 config ARCH_HAS_CPU_IDLE_WAIT
135 config GENERIC_CALIBRATE_DELAY
138 config GENERIC_TIME_VSYSCALL
142 config ARCH_HAS_CPU_RELAX
145 config ARCH_HAS_DEFAULT_IDLE
148 config ARCH_HAS_CACHE_LINE_SIZE
151 config HAVE_SETUP_PER_CPU_AREA
154 config NEED_PER_CPU_EMBED_FIRST_CHUNK
157 config NEED_PER_CPU_PAGE_FIRST_CHUNK
160 config HAVE_CPUMASK_OF_CPU_MAP
163 config ARCH_HIBERNATION_POSSIBLE
166 config ARCH_SUSPEND_POSSIBLE
173 config ARCH_POPULATES_NODE_MAP
180 config ARCH_SUPPORTS_OPTIMIZED_INLINING
183 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
186 config HAVE_INTEL_TXT
188 depends on EXPERIMENTAL && DMAR && ACPI
190 # Use the generic interrupt handling code in kernel/irq/:
191 config GENERIC_HARDIRQS
195 config GENERIC_HARDIRQS_NO__DO_IRQ
198 config GENERIC_IRQ_PROBE
202 config GENERIC_PENDING_IRQ
204 depends on GENERIC_HARDIRQS && SMP
207 config USE_GENERIC_SMP_HELPERS
213 depends on X86_32 && SMP
217 depends on X86_64 && SMP
224 config X86_TRAMPOLINE
226 depends on SMP || (64BIT && ACPI_SLEEP)
229 config X86_32_LAZY_GS
231 depends on X86_32 && !CC_STACKPROTECTOR
235 source "init/Kconfig"
236 source "kernel/Kconfig.freezer"
238 menu "Processor type and features"
240 source "kernel/time/Kconfig"
243 bool "Symmetric multi-processing support"
245 This enables support for systems with more than one CPU. If you have
246 a system with only one CPU, like most personal computers, say N. If
247 you have a system with more than one CPU, say Y.
249 If you say N here, the kernel will run on single and multiprocessor
250 machines, but will use only one CPU of a multiprocessor machine. If
251 you say Y here, the kernel will run on many, but not all,
252 singleprocessor machines. On a singleprocessor machine, the kernel
253 will run faster if you say N here.
255 Note that if you say Y here and choose architecture "586" or
256 "Pentium" under "Processor family", the kernel will not work on 486
257 architectures. Similarly, multiprocessor kernels for the "PPro"
258 architecture may not work on all Pentium based boards.
260 People using multiprocessor machines who say Y here should also say
261 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
262 Management" code will be disabled if you say Y here.
264 See also <file:Documentation/i386/IO-APIC.txt>,
265 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
266 <http://www.tldp.org/docs.html#howto>.
268 If you don't know what to do here, say N.
271 bool "Support x2apic"
272 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
274 This enables x2apic support on CPUs that have this feature.
276 This allows 32-bit apic IDs (so it can support very large systems),
277 and accesses the local apic via MSRs not via mmio.
279 If you don't know what to do here, say N.
282 bool "Support sparse irq numbering"
283 depends on PCI_MSI || HT_IRQ
285 This enables support for sparse irqs. This is useful for distro
286 kernels that want to define a high CONFIG_NR_CPUS value but still
287 want to have low kernel memory footprint on smaller machines.
289 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
290 out the irq_desc[] array in a more NUMA-friendly way. )
292 If you don't know what to do here, say N.
296 depends on SPARSE_IRQ && NUMA
299 bool "Enable MPS table" if ACPI
301 depends on X86_LOCAL_APIC
303 For old smp systems that do not have proper acpi support. Newer systems
304 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
307 bool "Support for big SMP systems with more than 8 CPUs"
308 depends on X86_32 && SMP
310 This option is needed for the systems that have more than 8 CPUs
313 config X86_EXTENDED_PLATFORM
314 bool "Support for extended (non-PC) x86 platforms"
317 If you disable this option then the kernel will only support
318 standard PC platforms. (which covers the vast majority of
321 If you enable this option then you'll be able to select support
322 for the following (non-PC) 32 bit x86 platforms:
326 SGI 320/540 (Visual Workstation)
327 Summit/EXA (IBM x440)
328 Unisys ES7000 IA32 series
329 Moorestown MID devices
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
336 config X86_EXTENDED_PLATFORM
337 bool "Support for extended (non-PC) x86 platforms"
340 If you disable this option then the kernel will only support
341 standard PC platforms. (which covers the vast majority of
344 If you enable this option then you'll be able to select support
345 for the following (non-PC) 64 bit x86 platforms:
349 If you have one of these systems, or if you want to build a
350 generic distribution kernel, say Y here - otherwise say N.
352 # This is an alphabetically sorted list of 64 bit extended platforms
353 # Please maintain the alphabetic order if and when there are additions
358 depends on X86_64 && PCI
359 depends on X86_EXTENDED_PLATFORM
361 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
362 supposed to run on these EM64T-based machines. Only choose this option
363 if you have one of these machines.
366 bool "SGI Ultraviolet"
368 depends on X86_EXTENDED_PLATFORM
370 depends on X86_X2APIC
372 This option is needed in order to support SGI Ultraviolet systems.
373 If you don't have one of these, you should say N here.
375 # Following is an alphabetically sorted list of 32 bit extended platforms
376 # Please maintain the alphabetic order if and when there are additions
381 depends on X86_EXTENDED_PLATFORM
383 Select this for an AMD Elan processor.
385 Do not use this option for K6/Athlon/Opteron processors!
387 If unsure, choose "PC-compatible" instead.
390 bool "Moorestown MID platform"
392 depends on X86_EXTENDED_PLATFORM
394 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
395 Internet Device(MID) platform. Moorestown consists of two chips:
396 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
397 Unlike standard x86 PCs, Moorestown does not have many legacy devices
398 nor standard legacy replacement devices/features. e.g. Moorestown does
399 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
402 bool "RDC R-321x SoC"
404 depends on X86_EXTENDED_PLATFORM
406 select X86_REBOOTFIXUPS
408 This option is needed for RDC R-321x system-on-chip, also known
410 If you don't have one of these chips, you should say N here.
412 config X86_32_NON_STANDARD
413 bool "Support non-standard 32-bit SMP architectures"
414 depends on X86_32 && SMP
415 depends on X86_EXTENDED_PLATFORM
417 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
418 subarchitectures. It is intended for a generic binary kernel.
419 if you select them all, kernel will probe it one by one. and will
422 # Alphabetically sorted list of Non standard 32 bit platforms
425 bool "NUMAQ (IBM/Sequent)"
426 depends on X86_32_NON_STANDARD
430 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
431 NUMA multiquad box. This changes the way that processors are
432 bootstrapped, and uses Clustered Logical APIC addressing mode instead
433 of Flat Logical. You will need a new lynxer.elf file to flash your
434 firmware with - send email to <Martin.Bligh@us.ibm.com>.
436 config X86_SUPPORTS_MEMORY_FAILURE
438 # MCE code calls memory_failure():
440 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
441 depends on !X86_NUMAQ
442 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
443 depends on X86_64 || !SPARSEMEM
444 select ARCH_SUPPORTS_MEMORY_FAILURE
448 bool "SGI 320/540 (Visual Workstation)"
449 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
450 depends on X86_32_NON_STANDARD
452 The SGI Visual Workstation series is an IA32-based workstation
453 based on SGI systems chips with some legacy PC hardware attached.
455 Say Y here to create a kernel to run on the SGI 320 or 540.
457 A kernel compiled for the Visual Workstation will run on general
458 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
461 bool "Summit/EXA (IBM x440)"
462 depends on X86_32_NON_STANDARD
464 This option is needed for IBM systems that use the Summit/EXA chipset.
465 In particular, it is needed for the x440.
468 bool "Unisys ES7000 IA32 series"
469 depends on X86_32_NON_STANDARD && X86_BIGSMP
471 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
472 supposed to run on an IA32-based Unisys ES7000 system.
474 config SCHED_OMIT_FRAME_POINTER
476 prompt "Single-depth WCHAN output"
479 Calculate simpler /proc/<PID>/wchan values. If this option
480 is disabled then wchan values will recurse back to the
481 caller function. This provides more accurate wchan values,
482 at the expense of slightly more scheduling overhead.
484 If in doubt, say "Y".
486 menuconfig PARAVIRT_GUEST
487 bool "Paravirtualized guest support"
489 Say Y here to get to see options related to running Linux under
490 various hypervisors. This option alone does not add any kernel code.
492 If you say N, all options in this submenu will be skipped and disabled.
496 source "arch/x86/xen/Kconfig"
499 bool "VMI Guest support (DEPRECATED)"
503 VMI provides a paravirtualized interface to the VMware ESX server
504 (it could be used by other hypervisors in theory too, but is not
505 at the moment), by linking the kernel to a GPL-ed ROM module
506 provided by the hypervisor.
508 As of September 2009, VMware has started a phased retirement
509 of this feature from VMware's products. Please see
510 feature-removal-schedule.txt for details. If you are
511 planning to enable this option, please note that you cannot
512 live migrate a VMI enabled VM to a future VMware product,
513 which doesn't support VMI. So if you expect your kernel to
514 seamlessly migrate to newer VMware products, keep this
518 bool "KVM paravirtualized clock"
520 select PARAVIRT_CLOCK
522 Turning on this option will allow you to run a paravirtualized clock
523 when running over the KVM hypervisor. Instead of relying on a PIT
524 (or probably other) emulation by the underlying device model, the host
525 provides the guest with timing infrastructure such as time of day, and
529 bool "KVM Guest support"
532 This option enables various optimizations for running under the KVM
535 source "arch/x86/lguest/Kconfig"
538 bool "Enable paravirtualization code"
540 This changes the kernel so it can modify itself when it is run
541 under a hypervisor, potentially improving performance significantly
542 over full virtualization. However, when run without a hypervisor
543 the kernel is theoretically slower and slightly larger.
545 config PARAVIRT_SPINLOCKS
546 bool "Paravirtualization layer for spinlocks"
547 depends on PARAVIRT && SMP && EXPERIMENTAL
549 Paravirtualized spinlocks allow a pvops backend to replace the
550 spinlock implementation with something virtualization-friendly
551 (for example, block the virtual CPU rather than spinning).
553 Unfortunately the downside is an up to 5% performance hit on
554 native kernels, with various workloads.
556 If you are unsure how to answer this question, answer N.
558 config PARAVIRT_CLOCK
564 config PARAVIRT_DEBUG
565 bool "paravirt-ops debugging"
566 depends on PARAVIRT && DEBUG_KERNEL
568 Enable to debug paravirt_ops internals. Specifically, BUG if
569 a paravirt_op is missing when it is called.
573 bool "Disable Bootmem code"
576 Use early_res directly instead of bootmem before slab is ready.
577 - allocator (buddy) [generic]
578 - early allocator (bootmem) [generic]
579 - very early allocator (reserve_early*()) [x86]
580 - very very early allocator (early brk model) [x86]
581 So reduce one layer between early allocator to final allocator
587 This option adds a kernel parameter 'memtest', which allows memtest
589 memtest=0, mean disabled; -- default
590 memtest=1, mean do 1 test pattern;
592 memtest=4, mean do 4 test patterns.
593 If you are unsure how to answer this question, answer N.
595 config X86_SUMMIT_NUMA
597 depends on X86_32 && NUMA && X86_32_NON_STANDARD
599 config X86_CYCLONE_TIMER
601 depends on X86_32_NON_STANDARD
603 source "arch/x86/Kconfig.cpu"
607 prompt "HPET Timer Support" if X86_32
609 Use the IA-PC HPET (High Precision Event Timer) to manage
610 time in preference to the PIT and RTC, if a HPET is
612 HPET is the next generation timer replacing legacy 8254s.
613 The HPET provides a stable time base on SMP
614 systems, unlike the TSC, but it is more expensive to access,
615 as it is off-chip. You can find the HPET spec at
616 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
618 You can safely choose Y here. However, HPET will only be
619 activated if the platform and the BIOS support this feature.
620 Otherwise the 8254 will be used for timing services.
622 Choose N to continue using the legacy 8254 timer.
624 config HPET_EMULATE_RTC
626 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
628 # Mark as embedded because too many people got it wrong.
629 # The code disables itself when not needed.
632 bool "Enable DMI scanning" if EMBEDDED
634 Enabled scanning of DMI to identify machine quirks. Say Y
635 here unless you have verified that your setup is not
636 affected by entries in the DMI blacklist. Required by PNP
640 bool "GART IOMMU support" if EMBEDDED
643 depends on X86_64 && PCI
645 Support for full DMA access of devices with 32bit memory access only
646 on systems with more than 3GB. This is usually needed for USB,
647 sound, many IDE/SATA chipsets and some other devices.
648 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
649 based hardware IOMMU and a software bounce buffer based IOMMU used
650 on Intel systems and as fallback.
651 The code is only active when needed (enough memory and limited
652 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
656 bool "IBM Calgary IOMMU support"
658 depends on X86_64 && PCI && EXPERIMENTAL
660 Support for hardware IOMMUs in IBM's xSeries x366 and x460
661 systems. Needed to run systems with more than 3GB of memory
662 properly with 32-bit PCI devices that do not support DAC
663 (Double Address Cycle). Calgary also supports bus level
664 isolation, where all DMAs pass through the IOMMU. This
665 prevents them from going anywhere except their intended
666 destination. This catches hard-to-find kernel bugs and
667 mis-behaving drivers and devices that do not use the DMA-API
668 properly to set up their DMA buffers. The IOMMU can be
669 turned off at boot time with the iommu=off parameter.
670 Normally the kernel will make the right choice by itself.
673 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
675 prompt "Should Calgary be enabled by default?"
676 depends on CALGARY_IOMMU
678 Should Calgary be enabled by default? if you choose 'y', Calgary
679 will be used (if it exists). If you choose 'n', Calgary will not be
680 used even if it exists. If you choose 'n' and would like to use
681 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
685 bool "AMD IOMMU support"
688 depends on X86_64 && PCI && ACPI
690 With this option you can enable support for AMD IOMMU hardware in
691 your system. An IOMMU is a hardware component which provides
692 remapping of DMA memory accesses from devices. With an AMD IOMMU you
693 can isolate the the DMA memory of different devices and protect the
694 system from misbehaving device drivers or hardware.
696 You can find out if your system has an AMD IOMMU if you look into
697 your BIOS for an option to enable it or if you have an IVRS ACPI
700 config AMD_IOMMU_STATS
701 bool "Export AMD IOMMU statistics to debugfs"
705 This option enables code in the AMD IOMMU driver to collect various
706 statistics about whats happening in the driver and exports that
707 information to userspace via debugfs.
710 # need this always selected by IOMMU for the VIA workaround
714 Support for software bounce buffers used on x86-64 systems
715 which don't have a hardware IOMMU (e.g. the current generation
716 of Intel's x86-64 CPUs). Using this PCI devices which can only
717 access 32-bits of memory can be used on systems with more than
718 3 GB of memory. If unsure, say Y.
721 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
724 def_bool (AMD_IOMMU || DMAR)
727 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
728 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
729 select CPUMASK_OFFSTACK
732 Configure maximum number of CPUS and NUMA Nodes for this architecture.
736 int "Maximum number of CPUs" if SMP && !MAXSMP
737 range 2 8 if SMP && X86_32 && !X86_BIGSMP
738 range 2 512 if SMP && !MAXSMP
740 default "4096" if MAXSMP
741 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
744 This allows you to specify the maximum number of CPUs which this
745 kernel will support. The maximum supported value is 512 and the
746 minimum value which makes sense is 2.
748 This is purely to save memory - each supported CPU adds
749 approximately eight kilobytes to the kernel image.
752 bool "SMT (Hyperthreading) scheduler support"
755 SMT scheduler support improves the CPU scheduler's decision making
756 when dealing with Intel Pentium 4 chips with HyperThreading at a
757 cost of slightly increased overhead in some places. If unsure say
762 prompt "Multi-core scheduler support"
765 Multi-core scheduler support improves the CPU scheduler's decision
766 making when dealing with multi-core CPU chips at a cost of slightly
767 increased overhead in some places. If unsure say N here.
769 source "kernel/Kconfig.preempt"
772 bool "Local APIC support on uniprocessors"
773 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
775 A local APIC (Advanced Programmable Interrupt Controller) is an
776 integrated interrupt controller in the CPU. If you have a single-CPU
777 system which has a processor with a local APIC, you can say Y here to
778 enable and use it. If you say Y here even though your machine doesn't
779 have a local APIC, then the kernel will still run with no slowdown at
780 all. The local APIC supports CPU-generated self-interrupts (timer,
781 performance counters), and the NMI watchdog which detects hard
785 bool "IO-APIC support on uniprocessors"
786 depends on X86_UP_APIC
788 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
789 SMP-capable replacement for PC-style interrupt controllers. Most
790 SMP systems and many recent uniprocessor systems have one.
792 If you have a single-CPU system with an IO-APIC, you can say Y here
793 to use it. If you say Y here even though your machine doesn't have
794 an IO-APIC, then the kernel will still run with no slowdown at all.
796 config X86_LOCAL_APIC
798 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
802 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
804 config X86_VISWS_APIC
806 depends on X86_32 && X86_VISWS
808 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
809 bool "Reroute for broken boot IRQs"
811 depends on X86_IO_APIC
813 This option enables a workaround that fixes a source of
814 spurious interrupts. This is recommended when threaded
815 interrupt handling is used on systems where the generation of
816 superfluous "boot interrupts" cannot be disabled.
818 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
819 entry in the chipset's IO-APIC is masked (as, e.g. the RT
820 kernel does during interrupt handling). On chipsets where this
821 boot IRQ generation cannot be disabled, this workaround keeps
822 the original IRQ line masked so that only the equivalent "boot
823 IRQ" is delivered to the CPUs. The workaround also tells the
824 kernel to set up the IRQ handler on the boot IRQ line. In this
825 way only one interrupt is delivered to the kernel. Otherwise
826 the spurious second interrupt may cause the kernel to bring
827 down (vital) interrupt lines.
829 Only affects "broken" chipsets. Interrupt sharing may be
830 increased on these systems.
833 bool "Machine Check / overheating reporting"
835 Machine Check support allows the processor to notify the
836 kernel if it detects a problem (e.g. overheating, data corruption).
837 The action the kernel takes depends on the severity of the problem,
838 ranging from warning messages to halting the machine.
842 prompt "Intel MCE features"
843 depends on X86_MCE && X86_LOCAL_APIC
845 Additional support for intel specific MCE features such as
850 prompt "AMD MCE features"
851 depends on X86_MCE && X86_LOCAL_APIC
853 Additional support for AMD specific MCE features such as
854 the DRAM Error Threshold.
856 config X86_ANCIENT_MCE
858 depends on X86_32 && X86_MCE
859 prompt "Support for old Pentium 5 / WinChip machine checks"
861 Include support for machine check handling on old Pentium 5 or WinChip
862 systems. These typically need to be enabled explicitely on the command
865 config X86_MCE_THRESHOLD
866 depends on X86_MCE_AMD || X86_MCE_INTEL
870 config X86_MCE_INJECT
872 tristate "Machine check injector support"
874 Provide support for injecting machine checks for testing purposes.
875 If you don't know what a machine check is and you don't do kernel
876 QA it is safe to say n.
878 config X86_THERMAL_VECTOR
880 depends on X86_MCE_INTEL
883 bool "Enable VM86 support" if EMBEDDED
887 This option is required by programs like DOSEMU to run 16-bit legacy
888 code on X86 processors. It also may be needed by software like
889 XFree86 to initialize some video cards via BIOS. Disabling this
890 option saves about 6k.
893 tristate "Toshiba Laptop support"
896 This adds a driver to safely access the System Management Mode of
897 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
898 not work on models with a Phoenix BIOS. The System Management Mode
899 is used to set the BIOS and power saving options on Toshiba portables.
901 For information on utilities to make use of this driver see the
902 Toshiba Linux utilities web site at:
903 <http://www.buzzard.org.uk/toshiba/>.
905 Say Y if you intend to run this kernel on a Toshiba portable.
909 tristate "Dell laptop support"
911 This adds a driver to safely access the System Management Mode
912 of the CPU on the Dell Inspiron 8000. The System Management Mode
913 is used to read cpu temperature and cooling fan status and to
914 control the fans on the I8K portables.
916 This driver has been tested only on the Inspiron 8000 but it may
917 also work with other Dell laptops. You can force loading on other
918 models by passing the parameter `force=1' to the module. Use at
921 For information on utilities to make use of this driver see the
922 I8K Linux utilities web site at:
923 <http://people.debian.org/~dz/i8k/>
925 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
928 config X86_REBOOTFIXUPS
929 bool "Enable X86 board specific fixups for reboot"
932 This enables chipset and/or board specific fixups to be done
933 in order to get reboot to work correctly. This is only needed on
934 some combinations of hardware and BIOS. The symptom, for which
935 this config is intended, is when reboot ends with a stalled/hung
938 Currently, the only fixup is for the Geode machines using
939 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
941 Say Y if you want to enable the fixup. Currently, it's safe to
942 enable this option even if you don't need it.
946 tristate "/dev/cpu/microcode - microcode support"
949 If you say Y here, you will be able to update the microcode on
950 certain Intel and AMD processors. The Intel support is for the
951 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
952 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
953 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
954 You will obviously need the actual microcode binary data itself
955 which is not shipped with the Linux kernel.
957 This option selects the general module only, you need to select
958 at least one vendor specific module as well.
960 To compile this driver as a module, choose M here: the
961 module will be called microcode.
963 config MICROCODE_INTEL
964 bool "Intel microcode patch loading support"
969 This options enables microcode patch loading support for Intel
972 For latest news and information on obtaining all the required
973 Intel ingredients for this driver, check:
974 <http://www.urbanmyth.org/microcode/>.
977 bool "AMD microcode patch loading support"
981 If you select this option, microcode patch loading support for AMD
982 processors will be enabled.
984 config MICROCODE_OLD_INTERFACE
989 tristate "/dev/cpu/*/msr - Model-specific register support"
991 This device gives privileged processes access to the x86
992 Model-Specific Registers (MSRs). It is a character device with
993 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
994 MSR accesses are directed to a specific CPU on multi-processor
998 tristate "/dev/cpu/*/cpuid - CPU information support"
1000 This device gives processes access to the x86 CPUID instruction to
1001 be executed on a specific processor. It is a character device
1002 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1006 prompt "High Memory Support"
1007 default HIGHMEM4G if !X86_NUMAQ
1008 default HIGHMEM64G if X86_NUMAQ
1013 depends on !X86_NUMAQ
1015 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1016 However, the address space of 32-bit x86 processors is only 4
1017 Gigabytes large. That means that, if you have a large amount of
1018 physical memory, not all of it can be "permanently mapped" by the
1019 kernel. The physical memory that's not permanently mapped is called
1022 If you are compiling a kernel which will never run on a machine with
1023 more than 1 Gigabyte total physical RAM, answer "off" here (default
1024 choice and suitable for most users). This will result in a "3GB/1GB"
1025 split: 3GB are mapped so that each process sees a 3GB virtual memory
1026 space and the remaining part of the 4GB virtual memory space is used
1027 by the kernel to permanently map as much physical memory as
1030 If the machine has between 1 and 4 Gigabytes physical RAM, then
1033 If more than 4 Gigabytes is used then answer "64GB" here. This
1034 selection turns Intel PAE (Physical Address Extension) mode on.
1035 PAE implements 3-level paging on IA32 processors. PAE is fully
1036 supported by Linux, PAE mode is implemented on all recent Intel
1037 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1038 then the kernel will not boot on CPUs that don't support PAE!
1040 The actual amount of total physical memory will either be
1041 auto detected or can be forced by using a kernel command line option
1042 such as "mem=256M". (Try "man bootparam" or see the documentation of
1043 your boot loader (lilo or loadlin) about how to pass options to the
1044 kernel at boot time.)
1046 If unsure, say "off".
1050 depends on !X86_NUMAQ
1052 Select this if you have a 32-bit processor and between 1 and 4
1053 gigabytes of physical RAM.
1057 depends on !M386 && !M486
1060 Select this if you have a 32-bit processor and more than 4
1061 gigabytes of physical RAM.
1066 depends on EXPERIMENTAL
1067 prompt "Memory split" if EMBEDDED
1071 Select the desired split between kernel and user memory.
1073 If the address range available to the kernel is less than the
1074 physical memory installed, the remaining memory will be available
1075 as "high memory". Accessing high memory is a little more costly
1076 than low memory, as it needs to be mapped into the kernel first.
1077 Note that increasing the kernel address space limits the range
1078 available to user programs, making the address space there
1079 tighter. Selecting anything other than the default 3G/1G split
1080 will also likely make your kernel incompatible with binary-only
1083 If you are not absolutely sure what you are doing, leave this
1087 bool "3G/1G user/kernel split"
1088 config VMSPLIT_3G_OPT
1090 bool "3G/1G user/kernel split (for full 1G low memory)"
1092 bool "2G/2G user/kernel split"
1093 config VMSPLIT_2G_OPT
1095 bool "2G/2G user/kernel split (for full 2G low memory)"
1097 bool "1G/3G user/kernel split"
1102 default 0xB0000000 if VMSPLIT_3G_OPT
1103 default 0x80000000 if VMSPLIT_2G
1104 default 0x78000000 if VMSPLIT_2G_OPT
1105 default 0x40000000 if VMSPLIT_1G
1111 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1114 bool "PAE (Physical Address Extension) Support"
1115 depends on X86_32 && !HIGHMEM4G
1117 PAE is required for NX support, and furthermore enables
1118 larger swapspace support for non-overcommit purposes. It
1119 has the cost of more pagetable lookup overhead, and also
1120 consumes more pagetable space per process.
1122 config ARCH_PHYS_ADDR_T_64BIT
1123 def_bool X86_64 || X86_PAE
1125 config DIRECT_GBPAGES
1126 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1130 Allow the kernel linear mapping to use 1GB pages on CPUs that
1131 support it. This can improve the kernel's performance a tiny bit by
1132 reducing TLB pressure. If in doubt, say "Y".
1134 # Common NUMA Features
1136 bool "Numa Memory Allocation and Scheduler Support"
1138 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1139 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1141 Enable NUMA (Non Uniform Memory Access) support.
1143 The kernel will try to allocate memory used by a CPU on the
1144 local memory controller of the CPU and add some more
1145 NUMA awareness to the kernel.
1147 For 64-bit this is recommended if the system is Intel Core i7
1148 (or later), AMD Opteron, or EM64T NUMA.
1150 For 32-bit this is only needed on (rare) 32-bit-only platforms
1151 that support NUMA topologies, such as NUMAQ / Summit, or if you
1152 boot a 32-bit kernel on a 64-bit NUMA platform.
1154 Otherwise, you should say N.
1156 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1157 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1161 prompt "Old style AMD Opteron NUMA detection"
1162 depends on X86_64 && NUMA && PCI
1164 Enable K8 NUMA node topology detection. You should say Y here if
1165 you have a multi processor AMD K8 system. This uses an old
1166 method to read the NUMA configuration directly from the builtin
1167 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1168 instead, which also takes priority if both are compiled in.
1170 config X86_64_ACPI_NUMA
1172 prompt "ACPI NUMA detection"
1173 depends on X86_64 && NUMA && ACPI && PCI
1176 Enable ACPI SRAT based node topology detection.
1178 # Some NUMA nodes have memory ranges that span
1179 # other nodes. Even though a pfn is valid and
1180 # between a node's start and end pfns, it may not
1181 # reside on that node. See memmap_init_zone()
1183 config NODES_SPAN_OTHER_NODES
1185 depends on X86_64_ACPI_NUMA
1188 bool "NUMA emulation"
1189 depends on X86_64 && NUMA
1191 Enable NUMA emulation. A flat machine will be split
1192 into virtual nodes when booted with "numa=fake=N", where N is the
1193 number of nodes. This is only useful for debugging.
1196 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1198 default "9" if MAXSMP
1199 default "6" if X86_64
1200 default "4" if X86_NUMAQ
1202 depends on NEED_MULTIPLE_NODES
1204 Specify the maximum number of NUMA Nodes available on the target
1205 system. Increases memory reserved to accommodate various tables.
1207 config HAVE_ARCH_BOOTMEM
1209 depends on X86_32 && NUMA
1211 config ARCH_HAVE_MEMORY_PRESENT
1213 depends on X86_32 && DISCONTIGMEM
1215 config NEED_NODE_MEMMAP_SIZE
1217 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1219 config HAVE_ARCH_ALLOC_REMAP
1221 depends on X86_32 && NUMA
1223 config ARCH_FLATMEM_ENABLE
1225 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1227 config ARCH_DISCONTIGMEM_ENABLE
1229 depends on NUMA && X86_32
1231 config ARCH_DISCONTIGMEM_DEFAULT
1233 depends on NUMA && X86_32
1235 config ARCH_PROC_KCORE_TEXT
1237 depends on X86_64 && PROC_KCORE
1239 config ARCH_SPARSEMEM_DEFAULT
1243 config ARCH_SPARSEMEM_ENABLE
1245 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1246 select SPARSEMEM_STATIC if X86_32
1247 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1249 config ARCH_SELECT_MEMORY_MODEL
1251 depends on ARCH_SPARSEMEM_ENABLE
1253 config ARCH_MEMORY_PROBE
1255 depends on MEMORY_HOTPLUG
1257 config ILLEGAL_POINTER_VALUE
1260 default 0xdead000000000000 if X86_64
1265 bool "Allocate 3rd-level pagetables from highmem"
1266 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1268 The VM uses one page table entry for each page of physical memory.
1269 For systems with a lot of RAM, this can be wasteful of precious
1270 low memory. Setting this option will put user-space page table
1271 entries in high memory.
1273 config X86_CHECK_BIOS_CORRUPTION
1274 bool "Check for low memory corruption"
1276 Periodically check for memory corruption in low memory, which
1277 is suspected to be caused by BIOS. Even when enabled in the
1278 configuration, it is disabled at runtime. Enable it by
1279 setting "memory_corruption_check=1" on the kernel command
1280 line. By default it scans the low 64k of memory every 60
1281 seconds; see the memory_corruption_check_size and
1282 memory_corruption_check_period parameters in
1283 Documentation/kernel-parameters.txt to adjust this.
1285 When enabled with the default parameters, this option has
1286 almost no overhead, as it reserves a relatively small amount
1287 of memory and scans it infrequently. It both detects corruption
1288 and prevents it from affecting the running system.
1290 It is, however, intended as a diagnostic tool; if repeatable
1291 BIOS-originated corruption always affects the same memory,
1292 you can use memmap= to prevent the kernel from using that
1295 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1296 bool "Set the default setting of memory_corruption_check"
1297 depends on X86_CHECK_BIOS_CORRUPTION
1300 Set whether the default state of memory_corruption_check is
1303 config X86_RESERVE_LOW_64K
1304 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1307 Reserve the first 64K of physical RAM on BIOSes that are known
1308 to potentially corrupt that memory range. A numbers of BIOSes are
1309 known to utilize this area during suspend/resume, so it must not
1310 be used by the kernel.
1312 Set this to N if you are absolutely sure that you trust the BIOS
1313 to get all its memory reservations and usages right.
1315 If you have doubts about the BIOS (e.g. suspend/resume does not
1316 work or there's kernel crashes after certain hardware hotplug
1317 events) and it's not AMI or Phoenix, then you might want to enable
1318 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1319 corruption patterns.
1323 config MATH_EMULATION
1325 prompt "Math emulation" if X86_32
1327 Linux can emulate a math coprocessor (used for floating point
1328 operations) if you don't have one. 486DX and Pentium processors have
1329 a math coprocessor built in, 486SX and 386 do not, unless you added
1330 a 487DX or 387, respectively. (The messages during boot time can
1331 give you some hints here ["man dmesg"].) Everyone needs either a
1332 coprocessor or this emulation.
1334 If you don't have a math coprocessor, you need to say Y here; if you
1335 say Y here even though you have a coprocessor, the coprocessor will
1336 be used nevertheless. (This behavior can be changed with the kernel
1337 command line option "no387", which comes handy if your coprocessor
1338 is broken. Try "man bootparam" or see the documentation of your boot
1339 loader (lilo or loadlin) about how to pass options to the kernel at
1340 boot time.) This means that it is a good idea to say Y here if you
1341 intend to use this kernel on different machines.
1343 More information about the internals of the Linux math coprocessor
1344 emulation can be found in <file:arch/x86/math-emu/README>.
1346 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1347 kernel, it won't hurt.
1352 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1354 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1355 the Memory Type Range Registers (MTRRs) may be used to control
1356 processor access to memory ranges. This is most useful if you have
1357 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1358 allows bus write transfers to be combined into a larger transfer
1359 before bursting over the PCI/AGP bus. This can increase performance
1360 of image write operations 2.5 times or more. Saying Y here creates a
1361 /proc/mtrr file which may be used to manipulate your processor's
1362 MTRRs. Typically the X server should use this.
1364 This code has a reasonably generic interface so that similar
1365 control registers on other processors can be easily supported
1368 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1369 Registers (ARRs) which provide a similar functionality to MTRRs. For
1370 these, the ARRs are used to emulate the MTRRs.
1371 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1372 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1373 write-combining. All of these processors are supported by this code
1374 and it makes sense to say Y here if you have one of them.
1376 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1377 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1378 can lead to all sorts of problems, so it's good to say Y here.
1380 You can safely say Y even if your machine doesn't have MTRRs, you'll
1381 just add about 9 KB to your kernel.
1383 See <file:Documentation/x86/mtrr.txt> for more information.
1385 config MTRR_SANITIZER
1387 prompt "MTRR cleanup support"
1390 Convert MTRR layout from continuous to discrete, so X drivers can
1391 add writeback entries.
1393 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1394 The largest mtrr entry size for a continuous block can be set with
1399 config MTRR_SANITIZER_ENABLE_DEFAULT
1400 int "MTRR cleanup enable value (0-1)"
1403 depends on MTRR_SANITIZER
1405 Enable mtrr cleanup default value
1407 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1408 int "MTRR cleanup spare reg num (0-7)"
1411 depends on MTRR_SANITIZER
1413 mtrr cleanup spare entries default, it can be changed via
1414 mtrr_spare_reg_nr=N on the kernel command line.
1419 prompt "x86 PAT support" if EMBEDDED
1422 Use PAT attributes to setup page level cache control.
1424 PATs are the modern equivalents of MTRRs and are much more
1425 flexible than MTRRs.
1427 Say N here if you see bootup problems (boot crash, boot hang,
1428 spontaneous reboots) or a non-working video driver.
1432 config ARCH_USES_PG_UNCACHED
1437 bool "EFI runtime service support"
1440 This enables the kernel to use EFI runtime services that are
1441 available (such as the EFI variable services).
1443 This option is only useful on systems that have EFI firmware.
1444 In addition, you should use the latest ELILO loader available
1445 at <http://elilo.sourceforge.net> in order to take advantage
1446 of EFI runtime services. However, even with this option, the
1447 resultant kernel should continue to boot on existing non-EFI
1452 prompt "Enable seccomp to safely compute untrusted bytecode"
1454 This kernel feature is useful for number crunching applications
1455 that may need to compute untrusted bytecode during their
1456 execution. By using pipes or other transports made available to
1457 the process as file descriptors supporting the read/write
1458 syscalls, it's possible to isolate those applications in
1459 their own address space using seccomp. Once seccomp is
1460 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1461 and the task is only allowed to execute a few safe syscalls
1462 defined by each seccomp mode.
1464 If unsure, say Y. Only embedded should say N here.
1466 config CC_STACKPROTECTOR
1467 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1469 This option turns on the -fstack-protector GCC feature. This
1470 feature puts, at the beginning of functions, a canary value on
1471 the stack just before the return address, and validates
1472 the value just before actually returning. Stack based buffer
1473 overflows (that need to overwrite this return address) now also
1474 overwrite the canary, which gets detected and the attack is then
1475 neutralized via a kernel panic.
1477 This feature requires gcc version 4.2 or above, or a distribution
1478 gcc with the feature backported. Older versions are automatically
1479 detected and for those versions, this configuration option is
1480 ignored. (and a warning is printed during bootup)
1482 source kernel/Kconfig.hz
1485 bool "kexec system call"
1487 kexec is a system call that implements the ability to shutdown your
1488 current kernel, and to start another kernel. It is like a reboot
1489 but it is independent of the system firmware. And like a reboot
1490 you can start any kernel with it, not just Linux.
1492 The name comes from the similarity to the exec system call.
1494 It is an ongoing process to be certain the hardware in a machine
1495 is properly shutdown, so do not be surprised if this code does not
1496 initially work for you. It may help to enable device hotplugging
1497 support. As of this writing the exact hardware interface is
1498 strongly in flux, so no good recommendation can be made.
1501 bool "kernel crash dumps"
1502 depends on X86_64 || (X86_32 && HIGHMEM)
1504 Generate crash dump after being started by kexec.
1505 This should be normally only set in special crash dump kernels
1506 which are loaded in the main kernel with kexec-tools into
1507 a specially reserved region and then later executed after
1508 a crash by kdump/kexec. The crash dump kernel must be compiled
1509 to a memory address not used by the main kernel or BIOS using
1510 PHYSICAL_START, or it must be built as a relocatable image
1511 (CONFIG_RELOCATABLE=y).
1512 For more details see Documentation/kdump/kdump.txt
1515 bool "kexec jump (EXPERIMENTAL)"
1516 depends on EXPERIMENTAL
1517 depends on KEXEC && HIBERNATION
1519 Jump between original kernel and kexeced kernel and invoke
1520 code in physical address mode via KEXEC
1522 config PHYSICAL_START
1523 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1526 This gives the physical address where the kernel is loaded.
1528 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1529 bzImage will decompress itself to above physical address and
1530 run from there. Otherwise, bzImage will run from the address where
1531 it has been loaded by the boot loader and will ignore above physical
1534 In normal kdump cases one does not have to set/change this option
1535 as now bzImage can be compiled as a completely relocatable image
1536 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1537 address. This option is mainly useful for the folks who don't want
1538 to use a bzImage for capturing the crash dump and want to use a
1539 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1540 to be specifically compiled to run from a specific memory area
1541 (normally a reserved region) and this option comes handy.
1543 So if you are using bzImage for capturing the crash dump,
1544 leave the value here unchanged to 0x1000000 and set
1545 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1546 for capturing the crash dump change this value to start of
1547 the reserved region. In other words, it can be set based on
1548 the "X" value as specified in the "crashkernel=YM@XM"
1549 command line boot parameter passed to the panic-ed
1550 kernel. Please take a look at Documentation/kdump/kdump.txt
1551 for more details about crash dumps.
1553 Usage of bzImage for capturing the crash dump is recommended as
1554 one does not have to build two kernels. Same kernel can be used
1555 as production kernel and capture kernel. Above option should have
1556 gone away after relocatable bzImage support is introduced. But it
1557 is present because there are users out there who continue to use
1558 vmlinux for dump capture. This option should go away down the
1561 Don't change this unless you know what you are doing.
1564 bool "Build a relocatable kernel"
1567 This builds a kernel image that retains relocation information
1568 so it can be loaded someplace besides the default 1MB.
1569 The relocations tend to make the kernel binary about 10% larger,
1570 but are discarded at runtime.
1572 One use is for the kexec on panic case where the recovery kernel
1573 must live at a different physical address than the primary
1576 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1577 it has been loaded at and the compile time physical address
1578 (CONFIG_PHYSICAL_START) is ignored.
1580 # Relocation on x86-32 needs some additional build support
1581 config X86_NEED_RELOCS
1583 depends on X86_32 && RELOCATABLE
1585 config PHYSICAL_ALIGN
1587 prompt "Alignment value to which kernel should be aligned" if X86_32
1589 range 0x2000 0x1000000
1591 This value puts the alignment restrictions on physical address
1592 where kernel is loaded and run from. Kernel is compiled for an
1593 address which meets above alignment restriction.
1595 If bootloader loads the kernel at a non-aligned address and
1596 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1597 address aligned to above value and run from there.
1599 If bootloader loads the kernel at a non-aligned address and
1600 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1601 load address and decompress itself to the address it has been
1602 compiled for and run from there. The address for which kernel is
1603 compiled already meets above alignment restrictions. Hence the
1604 end result is that kernel runs from a physical address meeting
1605 above alignment restrictions.
1607 Don't change this unless you know what you are doing.
1610 bool "Support for hot-pluggable CPUs"
1611 depends on SMP && HOTPLUG
1613 Say Y here to allow turning CPUs off and on. CPUs can be
1614 controlled through /sys/devices/system/cpu.
1615 ( Note: power management support will enable this option
1616 automatically on SMP systems. )
1617 Say N if you want to disable CPU hotplug.
1621 prompt "Compat VDSO support"
1622 depends on X86_32 || IA32_EMULATION
1624 Map the 32-bit VDSO to the predictable old-style address too.
1626 Say N here if you are running a sufficiently recent glibc
1627 version (2.3.3 or later), to remove the high-mapped
1628 VDSO mapping and to exclusively use the randomized VDSO.
1633 bool "Built-in kernel command line"
1636 Allow for specifying boot arguments to the kernel at
1637 build time. On some systems (e.g. embedded ones), it is
1638 necessary or convenient to provide some or all of the
1639 kernel boot arguments with the kernel itself (that is,
1640 to not rely on the boot loader to provide them.)
1642 To compile command line arguments into the kernel,
1643 set this option to 'Y', then fill in the
1644 the boot arguments in CONFIG_CMDLINE.
1646 Systems with fully functional boot loaders (i.e. non-embedded)
1647 should leave this option set to 'N'.
1650 string "Built-in kernel command string"
1651 depends on CMDLINE_BOOL
1654 Enter arguments here that should be compiled into the kernel
1655 image and used at boot time. If the boot loader provides a
1656 command line at boot time, it is appended to this string to
1657 form the full kernel command line, when the system boots.
1659 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1660 change this behavior.
1662 In most cases, the command line (whether built-in or provided
1663 by the boot loader) should specify the device for the root
1666 config CMDLINE_OVERRIDE
1667 bool "Built-in command line overrides boot loader arguments"
1669 depends on CMDLINE_BOOL
1671 Set this option to 'Y' to have the kernel ignore the boot loader
1672 command line, and use ONLY the built-in command line.
1674 This is used to work around broken boot loaders. This should
1675 be set to 'N' under normal conditions.
1679 config ARCH_ENABLE_MEMORY_HOTPLUG
1681 depends on X86_64 || (X86_32 && HIGHMEM)
1683 config ARCH_ENABLE_MEMORY_HOTREMOVE
1685 depends on MEMORY_HOTPLUG
1687 config HAVE_ARCH_EARLY_PFN_TO_NID
1691 menu "Power management and ACPI options"
1693 config ARCH_HIBERNATION_HEADER
1695 depends on X86_64 && HIBERNATION
1697 source "kernel/power/Kconfig"
1699 source "drivers/acpi/Kconfig"
1701 source "drivers/sfi/Kconfig"
1706 depends on APM || APM_MODULE
1709 tristate "APM (Advanced Power Management) BIOS support"
1710 depends on X86_32 && PM_SLEEP
1712 APM is a BIOS specification for saving power using several different
1713 techniques. This is mostly useful for battery powered laptops with
1714 APM compliant BIOSes. If you say Y here, the system time will be
1715 reset after a RESUME operation, the /proc/apm device will provide
1716 battery status information, and user-space programs will receive
1717 notification of APM "events" (e.g. battery status change).
1719 If you select "Y" here, you can disable actual use of the APM
1720 BIOS by passing the "apm=off" option to the kernel at boot time.
1722 Note that the APM support is almost completely disabled for
1723 machines with more than one CPU.
1725 In order to use APM, you will need supporting software. For location
1726 and more information, read <file:Documentation/power/pm.txt> and the
1727 Battery Powered Linux mini-HOWTO, available from
1728 <http://www.tldp.org/docs.html#howto>.
1730 This driver does not spin down disk drives (see the hdparm(8)
1731 manpage ("man 8 hdparm") for that), and it doesn't turn off
1732 VESA-compliant "green" monitors.
1734 This driver does not support the TI 4000M TravelMate and the ACER
1735 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1736 desktop machines also don't have compliant BIOSes, and this driver
1737 may cause those machines to panic during the boot phase.
1739 Generally, if you don't have a battery in your machine, there isn't
1740 much point in using this driver and you should say N. If you get
1741 random kernel OOPSes or reboots that don't seem to be related to
1742 anything, try disabling/enabling this option (or disabling/enabling
1745 Some other things you should try when experiencing seemingly random,
1748 1) make sure that you have enough swap space and that it is
1750 2) pass the "no-hlt" option to the kernel
1751 3) switch on floating point emulation in the kernel and pass
1752 the "no387" option to the kernel
1753 4) pass the "floppy=nodma" option to the kernel
1754 5) pass the "mem=4M" option to the kernel (thereby disabling
1755 all but the first 4 MB of RAM)
1756 6) make sure that the CPU is not over clocked.
1757 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1758 8) disable the cache from your BIOS settings
1759 9) install a fan for the video card or exchange video RAM
1760 10) install a better fan for the CPU
1761 11) exchange RAM chips
1762 12) exchange the motherboard.
1764 To compile this driver as a module, choose M here: the
1765 module will be called apm.
1769 config APM_IGNORE_USER_SUSPEND
1770 bool "Ignore USER SUSPEND"
1772 This option will ignore USER SUSPEND requests. On machines with a
1773 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1774 series notebooks, it is necessary to say Y because of a BIOS bug.
1776 config APM_DO_ENABLE
1777 bool "Enable PM at boot time"
1779 Enable APM features at boot time. From page 36 of the APM BIOS
1780 specification: "When disabled, the APM BIOS does not automatically
1781 power manage devices, enter the Standby State, enter the Suspend
1782 State, or take power saving steps in response to CPU Idle calls."
1783 This driver will make CPU Idle calls when Linux is idle (unless this
1784 feature is turned off -- see "Do CPU IDLE calls", below). This
1785 should always save battery power, but more complicated APM features
1786 will be dependent on your BIOS implementation. You may need to turn
1787 this option off if your computer hangs at boot time when using APM
1788 support, or if it beeps continuously instead of suspending. Turn
1789 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1790 T400CDT. This is off by default since most machines do fine without
1794 bool "Make CPU Idle calls when idle"
1796 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1797 On some machines, this can activate improved power savings, such as
1798 a slowed CPU clock rate, when the machine is idle. These idle calls
1799 are made after the idle loop has run for some length of time (e.g.,
1800 333 mS). On some machines, this will cause a hang at boot time or
1801 whenever the CPU becomes idle. (On machines with more than one CPU,
1802 this option does nothing.)
1804 config APM_DISPLAY_BLANK
1805 bool "Enable console blanking using APM"
1807 Enable console blanking using the APM. Some laptops can use this to
1808 turn off the LCD backlight when the screen blanker of the Linux
1809 virtual console blanks the screen. Note that this is only used by
1810 the virtual console screen blanker, and won't turn off the backlight
1811 when using the X Window system. This also doesn't have anything to
1812 do with your VESA-compliant power-saving monitor. Further, this
1813 option doesn't work for all laptops -- it might not turn off your
1814 backlight at all, or it might print a lot of errors to the console,
1815 especially if you are using gpm.
1817 config APM_ALLOW_INTS
1818 bool "Allow interrupts during APM BIOS calls"
1820 Normally we disable external interrupts while we are making calls to
1821 the APM BIOS as a measure to lessen the effects of a badly behaving
1822 BIOS implementation. The BIOS should reenable interrupts if it
1823 needs to. Unfortunately, some BIOSes do not -- especially those in
1824 many of the newer IBM Thinkpads. If you experience hangs when you
1825 suspend, try setting this to Y. Otherwise, say N.
1829 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1831 source "drivers/cpuidle/Kconfig"
1833 source "drivers/idle/Kconfig"
1838 menu "Bus options (PCI etc.)"
1843 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1845 Find out whether you have a PCI motherboard. PCI is the name of a
1846 bus system, i.e. the way the CPU talks to the other stuff inside
1847 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1848 VESA. If you have PCI, say Y, otherwise N.
1851 prompt "PCI access mode"
1852 depends on X86_32 && PCI
1855 On PCI systems, the BIOS can be used to detect the PCI devices and
1856 determine their configuration. However, some old PCI motherboards
1857 have BIOS bugs and may crash if this is done. Also, some embedded
1858 PCI-based systems don't have any BIOS at all. Linux can also try to
1859 detect the PCI hardware directly without using the BIOS.
1861 With this option, you can specify how Linux should detect the
1862 PCI devices. If you choose "BIOS", the BIOS will be used,
1863 if you choose "Direct", the BIOS won't be used, and if you
1864 choose "MMConfig", then PCI Express MMCONFIG will be used.
1865 If you choose "Any", the kernel will try MMCONFIG, then the
1866 direct access method and falls back to the BIOS if that doesn't
1867 work. If unsure, go with the default, which is "Any".
1872 config PCI_GOMMCONFIG
1889 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1891 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1894 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1898 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1902 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1909 bool "Support mmconfig PCI config space access"
1910 depends on X86_64 && PCI && ACPI
1913 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1914 depends on PCI_MSI && ACPI && EXPERIMENTAL
1916 DMA remapping (DMAR) devices support enables independent address
1917 translations for Direct Memory Access (DMA) from devices.
1918 These DMA remapping devices are reported via ACPI tables
1919 and include PCI device scope covered by these DMA
1922 config DMAR_DEFAULT_ON
1924 prompt "Enable DMA Remapping Devices by default"
1927 Selecting this option will enable a DMAR device at boot time if
1928 one is found. If this option is not selected, DMAR support can
1929 be enabled by passing intel_iommu=on to the kernel. It is
1930 recommended you say N here while the DMAR code remains
1933 config DMAR_BROKEN_GFX_WA
1935 prompt "Workaround broken graphics drivers (going away soon)"
1936 depends on DMAR && BROKEN
1938 Current Graphics drivers tend to use physical address
1939 for DMA and avoid using DMA APIs. Setting this config
1940 option permits the IOMMU driver to set a unity map for
1941 all the OS-visible memory. Hence the driver can continue
1942 to use physical addresses for DMA, at least until this
1943 option is removed in the 2.6.32 kernel.
1945 config DMAR_FLOPPY_WA
1949 Floppy disk drivers are known to bypass DMA API calls
1950 thereby failing to work when IOMMU is enabled. This
1951 workaround will setup a 1:1 mapping for the first
1952 16MiB to make floppy (an ISA device) work.
1955 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1956 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1958 Supports Interrupt remapping for IO-APIC and MSI devices.
1959 To use x2apic mode in the CPU's which support x2APIC enhancements or
1960 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1962 source "drivers/pci/pcie/Kconfig"
1964 source "drivers/pci/Kconfig"
1966 # x86_64 have no ISA slots, but do have ISA-style DMA.
1975 Find out whether you have ISA slots on your motherboard. ISA is the
1976 name of a bus system, i.e. the way the CPU talks to the other stuff
1977 inside your box. Other bus systems are PCI, EISA, MicroChannel
1978 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1979 newer boards don't support it. If you have ISA, say Y, otherwise N.
1985 The Extended Industry Standard Architecture (EISA) bus was
1986 developed as an open alternative to the IBM MicroChannel bus.
1988 The EISA bus provided some of the features of the IBM MicroChannel
1989 bus while maintaining backward compatibility with cards made for
1990 the older ISA bus. The EISA bus saw limited use between 1988 and
1991 1995 when it was made obsolete by the PCI bus.
1993 Say Y here if you are building a kernel for an EISA-based machine.
1997 source "drivers/eisa/Kconfig"
2002 MicroChannel Architecture is found in some IBM PS/2 machines and
2003 laptops. It is a bus system similar to PCI or ISA. See
2004 <file:Documentation/mca.txt> (and especially the web page given
2005 there) before attempting to build an MCA bus kernel.
2007 source "drivers/mca/Kconfig"
2010 tristate "NatSemi SCx200 support"
2012 This provides basic support for National Semiconductor's
2013 (now AMD's) Geode processors. The driver probes for the
2014 PCI-IDs of several on-chip devices, so its a good dependency
2015 for other scx200_* drivers.
2017 If compiled as a module, the driver is named scx200.
2019 config SCx200HR_TIMER
2020 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2021 depends on SCx200 && GENERIC_TIME
2024 This driver provides a clocksource built upon the on-chip
2025 27MHz high-resolution timer. Its also a workaround for
2026 NSC Geode SC-1100's buggy TSC, which loses time when the
2027 processor goes idle (as is done by the scheduler). The
2028 other workaround is idle=poll boot option.
2031 bool "One Laptop Per Child support"
2035 Add support for detecting the unique features of the OLPC
2042 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2044 source "drivers/pcmcia/Kconfig"
2046 source "drivers/pci/hotplug/Kconfig"
2051 menu "Executable file formats / Emulations"
2053 source "fs/Kconfig.binfmt"
2055 config IA32_EMULATION
2056 bool "IA32 Emulation"
2058 select COMPAT_BINFMT_ELF
2060 Include code to run 32-bit programs under a 64-bit kernel. You should
2061 likely turn this on, unless you're 100% sure that you don't have any
2062 32-bit programs left.
2065 tristate "IA32 a.out support"
2066 depends on IA32_EMULATION
2068 Support old a.out binaries in the 32bit emulation.
2072 depends on IA32_EMULATION
2074 config COMPAT_FOR_U64_ALIGNMENT
2078 config SYSVIPC_COMPAT
2080 depends on COMPAT && SYSVIPC
2085 config HAVE_ATOMIC_IOMAP
2089 source "net/Kconfig"
2091 source "drivers/Kconfig"
2093 source "drivers/firmware/Kconfig"
2097 source "arch/x86/Kconfig.debug"
2099 source "security/Kconfig"
2101 source "crypto/Kconfig"
2103 source "arch/x86/kvm/Kconfig"
2105 source "lib/Kconfig"