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
395 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
396 Internet Device(MID) platform. Moorestown consists of two chips:
397 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
398 Unlike standard x86 PCs, Moorestown does not have many legacy devices
399 nor standard legacy replacement devices/features. e.g. Moorestown does
400 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
403 bool "RDC R-321x SoC"
405 depends on X86_EXTENDED_PLATFORM
407 select X86_REBOOTFIXUPS
409 This option is needed for RDC R-321x system-on-chip, also known
411 If you don't have one of these chips, you should say N here.
413 config X86_32_NON_STANDARD
414 bool "Support non-standard 32-bit SMP architectures"
415 depends on X86_32 && SMP
416 depends on X86_EXTENDED_PLATFORM
418 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
419 subarchitectures. It is intended for a generic binary kernel.
420 if you select them all, kernel will probe it one by one. and will
423 # Alphabetically sorted list of Non standard 32 bit platforms
426 bool "NUMAQ (IBM/Sequent)"
427 depends on X86_32_NON_STANDARD
432 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
433 NUMA multiquad box. This changes the way that processors are
434 bootstrapped, and uses Clustered Logical APIC addressing mode instead
435 of Flat Logical. You will need a new lynxer.elf file to flash your
436 firmware with - send email to <Martin.Bligh@us.ibm.com>.
438 config X86_SUPPORTS_MEMORY_FAILURE
440 # MCE code calls memory_failure():
442 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
443 depends on !X86_NUMAQ
444 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
445 depends on X86_64 || !SPARSEMEM
446 select ARCH_SUPPORTS_MEMORY_FAILURE
450 bool "SGI 320/540 (Visual Workstation)"
451 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
452 depends on X86_32_NON_STANDARD
454 The SGI Visual Workstation series is an IA32-based workstation
455 based on SGI systems chips with some legacy PC hardware attached.
457 Say Y here to create a kernel to run on the SGI 320 or 540.
459 A kernel compiled for the Visual Workstation will run on general
460 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
463 bool "Summit/EXA (IBM x440)"
464 depends on X86_32_NON_STANDARD
466 This option is needed for IBM systems that use the Summit/EXA chipset.
467 In particular, it is needed for the x440.
470 bool "Unisys ES7000 IA32 series"
471 depends on X86_32_NON_STANDARD && X86_BIGSMP
473 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
474 supposed to run on an IA32-based Unisys ES7000 system.
476 config SCHED_OMIT_FRAME_POINTER
478 prompt "Single-depth WCHAN output"
481 Calculate simpler /proc/<PID>/wchan values. If this option
482 is disabled then wchan values will recurse back to the
483 caller function. This provides more accurate wchan values,
484 at the expense of slightly more scheduling overhead.
486 If in doubt, say "Y".
488 menuconfig PARAVIRT_GUEST
489 bool "Paravirtualized guest support"
491 Say Y here to get to see options related to running Linux under
492 various hypervisors. This option alone does not add any kernel code.
494 If you say N, all options in this submenu will be skipped and disabled.
498 source "arch/x86/xen/Kconfig"
501 bool "VMI Guest support (DEPRECATED)"
505 VMI provides a paravirtualized interface to the VMware ESX server
506 (it could be used by other hypervisors in theory too, but is not
507 at the moment), by linking the kernel to a GPL-ed ROM module
508 provided by the hypervisor.
510 As of September 2009, VMware has started a phased retirement
511 of this feature from VMware's products. Please see
512 feature-removal-schedule.txt for details. If you are
513 planning to enable this option, please note that you cannot
514 live migrate a VMI enabled VM to a future VMware product,
515 which doesn't support VMI. So if you expect your kernel to
516 seamlessly migrate to newer VMware products, keep this
520 bool "KVM paravirtualized clock"
522 select PARAVIRT_CLOCK
524 Turning on this option will allow you to run a paravirtualized clock
525 when running over the KVM hypervisor. Instead of relying on a PIT
526 (or probably other) emulation by the underlying device model, the host
527 provides the guest with timing infrastructure such as time of day, and
531 bool "KVM Guest support"
534 This option enables various optimizations for running under the KVM
537 source "arch/x86/lguest/Kconfig"
540 bool "Enable paravirtualization code"
542 This changes the kernel so it can modify itself when it is run
543 under a hypervisor, potentially improving performance significantly
544 over full virtualization. However, when run without a hypervisor
545 the kernel is theoretically slower and slightly larger.
547 config PARAVIRT_SPINLOCKS
548 bool "Paravirtualization layer for spinlocks"
549 depends on PARAVIRT && SMP && EXPERIMENTAL
551 Paravirtualized spinlocks allow a pvops backend to replace the
552 spinlock implementation with something virtualization-friendly
553 (for example, block the virtual CPU rather than spinning).
555 Unfortunately the downside is an up to 5% performance hit on
556 native kernels, with various workloads.
558 If you are unsure how to answer this question, answer N.
560 config PARAVIRT_CLOCK
566 config PARAVIRT_DEBUG
567 bool "paravirt-ops debugging"
568 depends on PARAVIRT && DEBUG_KERNEL
570 Enable to debug paravirt_ops internals. Specifically, BUG if
571 a paravirt_op is missing when it is called.
576 This option adds a kernel parameter 'memtest', which allows memtest
578 memtest=0, mean disabled; -- default
579 memtest=1, mean do 1 test pattern;
581 memtest=4, mean do 4 test patterns.
582 If you are unsure how to answer this question, answer N.
584 config X86_SUMMIT_NUMA
586 depends on X86_32 && NUMA && X86_32_NON_STANDARD
588 config X86_CYCLONE_TIMER
590 depends on X86_32_NON_STANDARD
592 source "arch/x86/Kconfig.cpu"
596 prompt "HPET Timer Support" if X86_32
598 Use the IA-PC HPET (High Precision Event Timer) to manage
599 time in preference to the PIT and RTC, if a HPET is
601 HPET is the next generation timer replacing legacy 8254s.
602 The HPET provides a stable time base on SMP
603 systems, unlike the TSC, but it is more expensive to access,
604 as it is off-chip. You can find the HPET spec at
605 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
607 You can safely choose Y here. However, HPET will only be
608 activated if the platform and the BIOS support this feature.
609 Otherwise the 8254 will be used for timing services.
611 Choose N to continue using the legacy 8254 timer.
613 config HPET_EMULATE_RTC
615 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
619 prompt "Langwell APB Timer Support" if X86_MRST
621 APB timer is the replacement for 8254, HPET on X86 MID platforms.
622 The APBT provides a stable time base on SMP
623 systems, unlike the TSC, but it is more expensive to access,
624 as it is off-chip. APB timers are always running regardless of CPU
625 C states, they are used as per CPU clockevent device when possible.
627 # Mark as embedded because too many people got it wrong.
628 # The code disables itself when not needed.
631 bool "Enable DMI scanning" if EMBEDDED
633 Enabled scanning of DMI to identify machine quirks. Say Y
634 here unless you have verified that your setup is not
635 affected by entries in the DMI blacklist. Required by PNP
639 bool "GART IOMMU support" if EMBEDDED
642 depends on X86_64 && PCI
644 Support for full DMA access of devices with 32bit memory access only
645 on systems with more than 3GB. This is usually needed for USB,
646 sound, many IDE/SATA chipsets and some other devices.
647 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
648 based hardware IOMMU and a software bounce buffer based IOMMU used
649 on Intel systems and as fallback.
650 The code is only active when needed (enough memory and limited
651 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
655 bool "IBM Calgary IOMMU support"
657 depends on X86_64 && PCI && EXPERIMENTAL
659 Support for hardware IOMMUs in IBM's xSeries x366 and x460
660 systems. Needed to run systems with more than 3GB of memory
661 properly with 32-bit PCI devices that do not support DAC
662 (Double Address Cycle). Calgary also supports bus level
663 isolation, where all DMAs pass through the IOMMU. This
664 prevents them from going anywhere except their intended
665 destination. This catches hard-to-find kernel bugs and
666 mis-behaving drivers and devices that do not use the DMA-API
667 properly to set up their DMA buffers. The IOMMU can be
668 turned off at boot time with the iommu=off parameter.
669 Normally the kernel will make the right choice by itself.
672 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
674 prompt "Should Calgary be enabled by default?"
675 depends on CALGARY_IOMMU
677 Should Calgary be enabled by default? if you choose 'y', Calgary
678 will be used (if it exists). If you choose 'n', Calgary will not be
679 used even if it exists. If you choose 'n' and would like to use
680 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
684 bool "AMD IOMMU support"
687 depends on X86_64 && PCI && ACPI
689 With this option you can enable support for AMD IOMMU hardware in
690 your system. An IOMMU is a hardware component which provides
691 remapping of DMA memory accesses from devices. With an AMD IOMMU you
692 can isolate the the DMA memory of different devices and protect the
693 system from misbehaving device drivers or hardware.
695 You can find out if your system has an AMD IOMMU if you look into
696 your BIOS for an option to enable it or if you have an IVRS ACPI
699 config AMD_IOMMU_STATS
700 bool "Export AMD IOMMU statistics to debugfs"
704 This option enables code in the AMD IOMMU driver to collect various
705 statistics about whats happening in the driver and exports that
706 information to userspace via debugfs.
709 # need this always selected by IOMMU for the VIA workaround
713 Support for software bounce buffers used on x86-64 systems
714 which don't have a hardware IOMMU (e.g. the current generation
715 of Intel's x86-64 CPUs). Using this PCI devices which can only
716 access 32-bits of memory can be used on systems with more than
717 3 GB of memory. If unsure, say Y.
720 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
723 def_bool (AMD_IOMMU || DMAR)
726 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
727 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
728 select CPUMASK_OFFSTACK
731 Configure maximum number of CPUS and NUMA Nodes for this architecture.
735 int "Maximum number of CPUs" if SMP && !MAXSMP
736 range 2 8 if SMP && X86_32 && !X86_BIGSMP
737 range 2 512 if SMP && !MAXSMP
739 default "4096" if MAXSMP
740 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
743 This allows you to specify the maximum number of CPUs which this
744 kernel will support. The maximum supported value is 512 and the
745 minimum value which makes sense is 2.
747 This is purely to save memory - each supported CPU adds
748 approximately eight kilobytes to the kernel image.
751 bool "SMT (Hyperthreading) scheduler support"
754 SMT scheduler support improves the CPU scheduler's decision making
755 when dealing with Intel Pentium 4 chips with HyperThreading at a
756 cost of slightly increased overhead in some places. If unsure say
761 prompt "Multi-core scheduler support"
764 Multi-core scheduler support improves the CPU scheduler's decision
765 making when dealing with multi-core CPU chips at a cost of slightly
766 increased overhead in some places. If unsure say N here.
768 source "kernel/Kconfig.preempt"
771 bool "Local APIC support on uniprocessors"
772 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
774 A local APIC (Advanced Programmable Interrupt Controller) is an
775 integrated interrupt controller in the CPU. If you have a single-CPU
776 system which has a processor with a local APIC, you can say Y here to
777 enable and use it. If you say Y here even though your machine doesn't
778 have a local APIC, then the kernel will still run with no slowdown at
779 all. The local APIC supports CPU-generated self-interrupts (timer,
780 performance counters), and the NMI watchdog which detects hard
784 bool "IO-APIC support on uniprocessors"
785 depends on X86_UP_APIC
787 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
788 SMP-capable replacement for PC-style interrupt controllers. Most
789 SMP systems and many recent uniprocessor systems have one.
791 If you have a single-CPU system with an IO-APIC, you can say Y here
792 to use it. If you say Y here even though your machine doesn't have
793 an IO-APIC, then the kernel will still run with no slowdown at all.
795 config X86_LOCAL_APIC
797 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
801 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
803 config X86_VISWS_APIC
805 depends on X86_32 && X86_VISWS
807 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
808 bool "Reroute for broken boot IRQs"
810 depends on X86_IO_APIC
812 This option enables a workaround that fixes a source of
813 spurious interrupts. This is recommended when threaded
814 interrupt handling is used on systems where the generation of
815 superfluous "boot interrupts" cannot be disabled.
817 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
818 entry in the chipset's IO-APIC is masked (as, e.g. the RT
819 kernel does during interrupt handling). On chipsets where this
820 boot IRQ generation cannot be disabled, this workaround keeps
821 the original IRQ line masked so that only the equivalent "boot
822 IRQ" is delivered to the CPUs. The workaround also tells the
823 kernel to set up the IRQ handler on the boot IRQ line. In this
824 way only one interrupt is delivered to the kernel. Otherwise
825 the spurious second interrupt may cause the kernel to bring
826 down (vital) interrupt lines.
828 Only affects "broken" chipsets. Interrupt sharing may be
829 increased on these systems.
832 bool "Machine Check / overheating reporting"
834 Machine Check support allows the processor to notify the
835 kernel if it detects a problem (e.g. overheating, data corruption).
836 The action the kernel takes depends on the severity of the problem,
837 ranging from warning messages to halting the machine.
841 prompt "Intel MCE features"
842 depends on X86_MCE && X86_LOCAL_APIC
844 Additional support for intel specific MCE features such as
849 prompt "AMD MCE features"
850 depends on X86_MCE && X86_LOCAL_APIC
852 Additional support for AMD specific MCE features such as
853 the DRAM Error Threshold.
855 config X86_ANCIENT_MCE
857 depends on X86_32 && X86_MCE
858 prompt "Support for old Pentium 5 / WinChip machine checks"
860 Include support for machine check handling on old Pentium 5 or WinChip
861 systems. These typically need to be enabled explicitely on the command
864 config X86_MCE_THRESHOLD
865 depends on X86_MCE_AMD || X86_MCE_INTEL
869 config X86_MCE_INJECT
871 tristate "Machine check injector support"
873 Provide support for injecting machine checks for testing purposes.
874 If you don't know what a machine check is and you don't do kernel
875 QA it is safe to say n.
877 config X86_THERMAL_VECTOR
879 depends on X86_MCE_INTEL
882 bool "Enable VM86 support" if EMBEDDED
886 This option is required by programs like DOSEMU to run 16-bit legacy
887 code on X86 processors. It also may be needed by software like
888 XFree86 to initialize some video cards via BIOS. Disabling this
889 option saves about 6k.
892 tristate "Toshiba Laptop support"
895 This adds a driver to safely access the System Management Mode of
896 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
897 not work on models with a Phoenix BIOS. The System Management Mode
898 is used to set the BIOS and power saving options on Toshiba portables.
900 For information on utilities to make use of this driver see the
901 Toshiba Linux utilities web site at:
902 <http://www.buzzard.org.uk/toshiba/>.
904 Say Y if you intend to run this kernel on a Toshiba portable.
908 tristate "Dell laptop support"
910 This adds a driver to safely access the System Management Mode
911 of the CPU on the Dell Inspiron 8000. The System Management Mode
912 is used to read cpu temperature and cooling fan status and to
913 control the fans on the I8K portables.
915 This driver has been tested only on the Inspiron 8000 but it may
916 also work with other Dell laptops. You can force loading on other
917 models by passing the parameter `force=1' to the module. Use at
920 For information on utilities to make use of this driver see the
921 I8K Linux utilities web site at:
922 <http://people.debian.org/~dz/i8k/>
924 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
927 config X86_REBOOTFIXUPS
928 bool "Enable X86 board specific fixups for reboot"
931 This enables chipset and/or board specific fixups to be done
932 in order to get reboot to work correctly. This is only needed on
933 some combinations of hardware and BIOS. The symptom, for which
934 this config is intended, is when reboot ends with a stalled/hung
937 Currently, the only fixup is for the Geode machines using
938 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
940 Say Y if you want to enable the fixup. Currently, it's safe to
941 enable this option even if you don't need it.
945 tristate "/dev/cpu/microcode - microcode support"
948 If you say Y here, you will be able to update the microcode on
949 certain Intel and AMD processors. The Intel support is for the
950 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
951 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
952 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
953 You will obviously need the actual microcode binary data itself
954 which is not shipped with the Linux kernel.
956 This option selects the general module only, you need to select
957 at least one vendor specific module as well.
959 To compile this driver as a module, choose M here: the
960 module will be called microcode.
962 config MICROCODE_INTEL
963 bool "Intel microcode patch loading support"
968 This options enables microcode patch loading support for Intel
971 For latest news and information on obtaining all the required
972 Intel ingredients for this driver, check:
973 <http://www.urbanmyth.org/microcode/>.
976 bool "AMD microcode patch loading support"
980 If you select this option, microcode patch loading support for AMD
981 processors will be enabled.
983 config MICROCODE_OLD_INTERFACE
988 tristate "/dev/cpu/*/msr - Model-specific register support"
990 This device gives privileged processes access to the x86
991 Model-Specific Registers (MSRs). It is a character device with
992 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
993 MSR accesses are directed to a specific CPU on multi-processor
997 tristate "/dev/cpu/*/cpuid - CPU information support"
999 This device gives processes access to the x86 CPUID instruction to
1000 be executed on a specific processor. It is a character device
1001 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1005 prompt "High Memory Support"
1006 default HIGHMEM4G if !X86_NUMAQ
1007 default HIGHMEM64G if X86_NUMAQ
1012 depends on !X86_NUMAQ
1014 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1015 However, the address space of 32-bit x86 processors is only 4
1016 Gigabytes large. That means that, if you have a large amount of
1017 physical memory, not all of it can be "permanently mapped" by the
1018 kernel. The physical memory that's not permanently mapped is called
1021 If you are compiling a kernel which will never run on a machine with
1022 more than 1 Gigabyte total physical RAM, answer "off" here (default
1023 choice and suitable for most users). This will result in a "3GB/1GB"
1024 split: 3GB are mapped so that each process sees a 3GB virtual memory
1025 space and the remaining part of the 4GB virtual memory space is used
1026 by the kernel to permanently map as much physical memory as
1029 If the machine has between 1 and 4 Gigabytes physical RAM, then
1032 If more than 4 Gigabytes is used then answer "64GB" here. This
1033 selection turns Intel PAE (Physical Address Extension) mode on.
1034 PAE implements 3-level paging on IA32 processors. PAE is fully
1035 supported by Linux, PAE mode is implemented on all recent Intel
1036 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1037 then the kernel will not boot on CPUs that don't support PAE!
1039 The actual amount of total physical memory will either be
1040 auto detected or can be forced by using a kernel command line option
1041 such as "mem=256M". (Try "man bootparam" or see the documentation of
1042 your boot loader (lilo or loadlin) about how to pass options to the
1043 kernel at boot time.)
1045 If unsure, say "off".
1049 depends on !X86_NUMAQ
1051 Select this if you have a 32-bit processor and between 1 and 4
1052 gigabytes of physical RAM.
1056 depends on !M386 && !M486
1059 Select this if you have a 32-bit processor and more than 4
1060 gigabytes of physical RAM.
1065 depends on EXPERIMENTAL
1066 prompt "Memory split" if EMBEDDED
1070 Select the desired split between kernel and user memory.
1072 If the address range available to the kernel is less than the
1073 physical memory installed, the remaining memory will be available
1074 as "high memory". Accessing high memory is a little more costly
1075 than low memory, as it needs to be mapped into the kernel first.
1076 Note that increasing the kernel address space limits the range
1077 available to user programs, making the address space there
1078 tighter. Selecting anything other than the default 3G/1G split
1079 will also likely make your kernel incompatible with binary-only
1082 If you are not absolutely sure what you are doing, leave this
1086 bool "3G/1G user/kernel split"
1087 config VMSPLIT_3G_OPT
1089 bool "3G/1G user/kernel split (for full 1G low memory)"
1091 bool "2G/2G user/kernel split"
1092 config VMSPLIT_2G_OPT
1094 bool "2G/2G user/kernel split (for full 2G low memory)"
1096 bool "1G/3G user/kernel split"
1101 default 0xB0000000 if VMSPLIT_3G_OPT
1102 default 0x80000000 if VMSPLIT_2G
1103 default 0x78000000 if VMSPLIT_2G_OPT
1104 default 0x40000000 if VMSPLIT_1G
1110 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1113 bool "PAE (Physical Address Extension) Support"
1114 depends on X86_32 && !HIGHMEM4G
1116 PAE is required for NX support, and furthermore enables
1117 larger swapspace support for non-overcommit purposes. It
1118 has the cost of more pagetable lookup overhead, and also
1119 consumes more pagetable space per process.
1121 config ARCH_PHYS_ADDR_T_64BIT
1122 def_bool X86_64 || X86_PAE
1124 config DIRECT_GBPAGES
1125 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1129 Allow the kernel linear mapping to use 1GB pages on CPUs that
1130 support it. This can improve the kernel's performance a tiny bit by
1131 reducing TLB pressure. If in doubt, say "Y".
1133 # Common NUMA Features
1135 bool "Numa Memory Allocation and Scheduler Support"
1137 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1138 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1140 Enable NUMA (Non Uniform Memory Access) support.
1142 The kernel will try to allocate memory used by a CPU on the
1143 local memory controller of the CPU and add some more
1144 NUMA awareness to the kernel.
1146 For 64-bit this is recommended if the system is Intel Core i7
1147 (or later), AMD Opteron, or EM64T NUMA.
1149 For 32-bit this is only needed on (rare) 32-bit-only platforms
1150 that support NUMA topologies, such as NUMAQ / Summit, or if you
1151 boot a 32-bit kernel on a 64-bit NUMA platform.
1153 Otherwise, you should say N.
1155 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1156 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1160 prompt "Old style AMD Opteron NUMA detection"
1161 depends on X86_64 && NUMA && PCI
1163 Enable K8 NUMA node topology detection. You should say Y here if
1164 you have a multi processor AMD K8 system. This uses an old
1165 method to read the NUMA configuration directly from the builtin
1166 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1167 instead, which also takes priority if both are compiled in.
1169 config X86_64_ACPI_NUMA
1171 prompt "ACPI NUMA detection"
1172 depends on X86_64 && NUMA && ACPI && PCI
1175 Enable ACPI SRAT based node topology detection.
1177 # Some NUMA nodes have memory ranges that span
1178 # other nodes. Even though a pfn is valid and
1179 # between a node's start and end pfns, it may not
1180 # reside on that node. See memmap_init_zone()
1182 config NODES_SPAN_OTHER_NODES
1184 depends on X86_64_ACPI_NUMA
1187 bool "NUMA emulation"
1188 depends on X86_64 && NUMA
1190 Enable NUMA emulation. A flat machine will be split
1191 into virtual nodes when booted with "numa=fake=N", where N is the
1192 number of nodes. This is only useful for debugging.
1195 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1197 default "9" if MAXSMP
1198 default "6" if X86_64
1199 default "4" if X86_NUMAQ
1201 depends on NEED_MULTIPLE_NODES
1203 Specify the maximum number of NUMA Nodes available on the target
1204 system. Increases memory reserved to accommodate various tables.
1206 config HAVE_ARCH_BOOTMEM
1208 depends on X86_32 && NUMA
1210 config ARCH_HAVE_MEMORY_PRESENT
1212 depends on X86_32 && DISCONTIGMEM
1214 config NEED_NODE_MEMMAP_SIZE
1216 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1218 config HAVE_ARCH_ALLOC_REMAP
1220 depends on X86_32 && NUMA
1222 config ARCH_FLATMEM_ENABLE
1224 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1226 config ARCH_DISCONTIGMEM_ENABLE
1228 depends on NUMA && X86_32
1230 config ARCH_DISCONTIGMEM_DEFAULT
1232 depends on NUMA && X86_32
1234 config ARCH_PROC_KCORE_TEXT
1236 depends on X86_64 && PROC_KCORE
1238 config ARCH_SPARSEMEM_DEFAULT
1242 config ARCH_SPARSEMEM_ENABLE
1244 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1245 select SPARSEMEM_STATIC if X86_32
1246 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1248 config ARCH_SELECT_MEMORY_MODEL
1250 depends on ARCH_SPARSEMEM_ENABLE
1252 config ARCH_MEMORY_PROBE
1254 depends on MEMORY_HOTPLUG
1256 config ILLEGAL_POINTER_VALUE
1259 default 0xdead000000000000 if X86_64
1264 bool "Allocate 3rd-level pagetables from highmem"
1265 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1267 The VM uses one page table entry for each page of physical memory.
1268 For systems with a lot of RAM, this can be wasteful of precious
1269 low memory. Setting this option will put user-space page table
1270 entries in high memory.
1272 config X86_CHECK_BIOS_CORRUPTION
1273 bool "Check for low memory corruption"
1275 Periodically check for memory corruption in low memory, which
1276 is suspected to be caused by BIOS. Even when enabled in the
1277 configuration, it is disabled at runtime. Enable it by
1278 setting "memory_corruption_check=1" on the kernel command
1279 line. By default it scans the low 64k of memory every 60
1280 seconds; see the memory_corruption_check_size and
1281 memory_corruption_check_period parameters in
1282 Documentation/kernel-parameters.txt to adjust this.
1284 When enabled with the default parameters, this option has
1285 almost no overhead, as it reserves a relatively small amount
1286 of memory and scans it infrequently. It both detects corruption
1287 and prevents it from affecting the running system.
1289 It is, however, intended as a diagnostic tool; if repeatable
1290 BIOS-originated corruption always affects the same memory,
1291 you can use memmap= to prevent the kernel from using that
1294 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1295 bool "Set the default setting of memory_corruption_check"
1296 depends on X86_CHECK_BIOS_CORRUPTION
1299 Set whether the default state of memory_corruption_check is
1302 config X86_RESERVE_LOW_64K
1303 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1306 Reserve the first 64K of physical RAM on BIOSes that are known
1307 to potentially corrupt that memory range. A numbers of BIOSes are
1308 known to utilize this area during suspend/resume, so it must not
1309 be used by the kernel.
1311 Set this to N if you are absolutely sure that you trust the BIOS
1312 to get all its memory reservations and usages right.
1314 If you have doubts about the BIOS (e.g. suspend/resume does not
1315 work or there's kernel crashes after certain hardware hotplug
1316 events) and it's not AMI or Phoenix, then you might want to enable
1317 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1318 corruption patterns.
1322 config MATH_EMULATION
1324 prompt "Math emulation" if X86_32
1326 Linux can emulate a math coprocessor (used for floating point
1327 operations) if you don't have one. 486DX and Pentium processors have
1328 a math coprocessor built in, 486SX and 386 do not, unless you added
1329 a 487DX or 387, respectively. (The messages during boot time can
1330 give you some hints here ["man dmesg"].) Everyone needs either a
1331 coprocessor or this emulation.
1333 If you don't have a math coprocessor, you need to say Y here; if you
1334 say Y here even though you have a coprocessor, the coprocessor will
1335 be used nevertheless. (This behavior can be changed with the kernel
1336 command line option "no387", which comes handy if your coprocessor
1337 is broken. Try "man bootparam" or see the documentation of your boot
1338 loader (lilo or loadlin) about how to pass options to the kernel at
1339 boot time.) This means that it is a good idea to say Y here if you
1340 intend to use this kernel on different machines.
1342 More information about the internals of the Linux math coprocessor
1343 emulation can be found in <file:arch/x86/math-emu/README>.
1345 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1346 kernel, it won't hurt.
1351 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1353 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1354 the Memory Type Range Registers (MTRRs) may be used to control
1355 processor access to memory ranges. This is most useful if you have
1356 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1357 allows bus write transfers to be combined into a larger transfer
1358 before bursting over the PCI/AGP bus. This can increase performance
1359 of image write operations 2.5 times or more. Saying Y here creates a
1360 /proc/mtrr file which may be used to manipulate your processor's
1361 MTRRs. Typically the X server should use this.
1363 This code has a reasonably generic interface so that similar
1364 control registers on other processors can be easily supported
1367 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1368 Registers (ARRs) which provide a similar functionality to MTRRs. For
1369 these, the ARRs are used to emulate the MTRRs.
1370 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1371 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1372 write-combining. All of these processors are supported by this code
1373 and it makes sense to say Y here if you have one of them.
1375 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1376 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1377 can lead to all sorts of problems, so it's good to say Y here.
1379 You can safely say Y even if your machine doesn't have MTRRs, you'll
1380 just add about 9 KB to your kernel.
1382 See <file:Documentation/x86/mtrr.txt> for more information.
1384 config MTRR_SANITIZER
1386 prompt "MTRR cleanup support"
1389 Convert MTRR layout from continuous to discrete, so X drivers can
1390 add writeback entries.
1392 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1393 The largest mtrr entry size for a continuous block can be set with
1398 config MTRR_SANITIZER_ENABLE_DEFAULT
1399 int "MTRR cleanup enable value (0-1)"
1402 depends on MTRR_SANITIZER
1404 Enable mtrr cleanup default value
1406 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1407 int "MTRR cleanup spare reg num (0-7)"
1410 depends on MTRR_SANITIZER
1412 mtrr cleanup spare entries default, it can be changed via
1413 mtrr_spare_reg_nr=N on the kernel command line.
1418 prompt "x86 PAT support" if EMBEDDED
1421 Use PAT attributes to setup page level cache control.
1423 PATs are the modern equivalents of MTRRs and are much more
1424 flexible than MTRRs.
1426 Say N here if you see bootup problems (boot crash, boot hang,
1427 spontaneous reboots) or a non-working video driver.
1431 config ARCH_USES_PG_UNCACHED
1436 bool "EFI runtime service support"
1439 This enables the kernel to use EFI runtime services that are
1440 available (such as the EFI variable services).
1442 This option is only useful on systems that have EFI firmware.
1443 In addition, you should use the latest ELILO loader available
1444 at <http://elilo.sourceforge.net> in order to take advantage
1445 of EFI runtime services. However, even with this option, the
1446 resultant kernel should continue to boot on existing non-EFI
1451 prompt "Enable seccomp to safely compute untrusted bytecode"
1453 This kernel feature is useful for number crunching applications
1454 that may need to compute untrusted bytecode during their
1455 execution. By using pipes or other transports made available to
1456 the process as file descriptors supporting the read/write
1457 syscalls, it's possible to isolate those applications in
1458 their own address space using seccomp. Once seccomp is
1459 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1460 and the task is only allowed to execute a few safe syscalls
1461 defined by each seccomp mode.
1463 If unsure, say Y. Only embedded should say N here.
1465 config CC_STACKPROTECTOR
1466 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1468 This option turns on the -fstack-protector GCC feature. This
1469 feature puts, at the beginning of functions, a canary value on
1470 the stack just before the return address, and validates
1471 the value just before actually returning. Stack based buffer
1472 overflows (that need to overwrite this return address) now also
1473 overwrite the canary, which gets detected and the attack is then
1474 neutralized via a kernel panic.
1476 This feature requires gcc version 4.2 or above, or a distribution
1477 gcc with the feature backported. Older versions are automatically
1478 detected and for those versions, this configuration option is
1479 ignored. (and a warning is printed during bootup)
1481 source kernel/Kconfig.hz
1484 bool "kexec system call"
1486 kexec is a system call that implements the ability to shutdown your
1487 current kernel, and to start another kernel. It is like a reboot
1488 but it is independent of the system firmware. And like a reboot
1489 you can start any kernel with it, not just Linux.
1491 The name comes from the similarity to the exec system call.
1493 It is an ongoing process to be certain the hardware in a machine
1494 is properly shutdown, so do not be surprised if this code does not
1495 initially work for you. It may help to enable device hotplugging
1496 support. As of this writing the exact hardware interface is
1497 strongly in flux, so no good recommendation can be made.
1500 bool "kernel crash dumps"
1501 depends on X86_64 || (X86_32 && HIGHMEM)
1503 Generate crash dump after being started by kexec.
1504 This should be normally only set in special crash dump kernels
1505 which are loaded in the main kernel with kexec-tools into
1506 a specially reserved region and then later executed after
1507 a crash by kdump/kexec. The crash dump kernel must be compiled
1508 to a memory address not used by the main kernel or BIOS using
1509 PHYSICAL_START, or it must be built as a relocatable image
1510 (CONFIG_RELOCATABLE=y).
1511 For more details see Documentation/kdump/kdump.txt
1514 bool "kexec jump (EXPERIMENTAL)"
1515 depends on EXPERIMENTAL
1516 depends on KEXEC && HIBERNATION
1518 Jump between original kernel and kexeced kernel and invoke
1519 code in physical address mode via KEXEC
1521 config PHYSICAL_START
1522 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1525 This gives the physical address where the kernel is loaded.
1527 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1528 bzImage will decompress itself to above physical address and
1529 run from there. Otherwise, bzImage will run from the address where
1530 it has been loaded by the boot loader and will ignore above physical
1533 In normal kdump cases one does not have to set/change this option
1534 as now bzImage can be compiled as a completely relocatable image
1535 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1536 address. This option is mainly useful for the folks who don't want
1537 to use a bzImage for capturing the crash dump and want to use a
1538 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1539 to be specifically compiled to run from a specific memory area
1540 (normally a reserved region) and this option comes handy.
1542 So if you are using bzImage for capturing the crash dump,
1543 leave the value here unchanged to 0x1000000 and set
1544 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1545 for capturing the crash dump change this value to start of
1546 the reserved region. In other words, it can be set based on
1547 the "X" value as specified in the "crashkernel=YM@XM"
1548 command line boot parameter passed to the panic-ed
1549 kernel. Please take a look at Documentation/kdump/kdump.txt
1550 for more details about crash dumps.
1552 Usage of bzImage for capturing the crash dump is recommended as
1553 one does not have to build two kernels. Same kernel can be used
1554 as production kernel and capture kernel. Above option should have
1555 gone away after relocatable bzImage support is introduced. But it
1556 is present because there are users out there who continue to use
1557 vmlinux for dump capture. This option should go away down the
1560 Don't change this unless you know what you are doing.
1563 bool "Build a relocatable kernel"
1566 This builds a kernel image that retains relocation information
1567 so it can be loaded someplace besides the default 1MB.
1568 The relocations tend to make the kernel binary about 10% larger,
1569 but are discarded at runtime.
1571 One use is for the kexec on panic case where the recovery kernel
1572 must live at a different physical address than the primary
1575 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1576 it has been loaded at and the compile time physical address
1577 (CONFIG_PHYSICAL_START) is ignored.
1579 # Relocation on x86-32 needs some additional build support
1580 config X86_NEED_RELOCS
1582 depends on X86_32 && RELOCATABLE
1584 config PHYSICAL_ALIGN
1586 prompt "Alignment value to which kernel should be aligned" if X86_32
1588 range 0x2000 0x1000000
1590 This value puts the alignment restrictions on physical address
1591 where kernel is loaded and run from. Kernel is compiled for an
1592 address which meets above alignment restriction.
1594 If bootloader loads the kernel at a non-aligned address and
1595 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1596 address aligned to above value and run from there.
1598 If bootloader loads the kernel at a non-aligned address and
1599 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1600 load address and decompress itself to the address it has been
1601 compiled for and run from there. The address for which kernel is
1602 compiled already meets above alignment restrictions. Hence the
1603 end result is that kernel runs from a physical address meeting
1604 above alignment restrictions.
1606 Don't change this unless you know what you are doing.
1609 bool "Support for hot-pluggable CPUs"
1610 depends on SMP && HOTPLUG
1612 Say Y here to allow turning CPUs off and on. CPUs can be
1613 controlled through /sys/devices/system/cpu.
1614 ( Note: power management support will enable this option
1615 automatically on SMP systems. )
1616 Say N if you want to disable CPU hotplug.
1620 prompt "Compat VDSO support"
1621 depends on X86_32 || IA32_EMULATION
1623 Map the 32-bit VDSO to the predictable old-style address too.
1625 Say N here if you are running a sufficiently recent glibc
1626 version (2.3.3 or later), to remove the high-mapped
1627 VDSO mapping and to exclusively use the randomized VDSO.
1632 bool "Built-in kernel command line"
1635 Allow for specifying boot arguments to the kernel at
1636 build time. On some systems (e.g. embedded ones), it is
1637 necessary or convenient to provide some or all of the
1638 kernel boot arguments with the kernel itself (that is,
1639 to not rely on the boot loader to provide them.)
1641 To compile command line arguments into the kernel,
1642 set this option to 'Y', then fill in the
1643 the boot arguments in CONFIG_CMDLINE.
1645 Systems with fully functional boot loaders (i.e. non-embedded)
1646 should leave this option set to 'N'.
1649 string "Built-in kernel command string"
1650 depends on CMDLINE_BOOL
1653 Enter arguments here that should be compiled into the kernel
1654 image and used at boot time. If the boot loader provides a
1655 command line at boot time, it is appended to this string to
1656 form the full kernel command line, when the system boots.
1658 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1659 change this behavior.
1661 In most cases, the command line (whether built-in or provided
1662 by the boot loader) should specify the device for the root
1665 config CMDLINE_OVERRIDE
1666 bool "Built-in command line overrides boot loader arguments"
1668 depends on CMDLINE_BOOL
1670 Set this option to 'Y' to have the kernel ignore the boot loader
1671 command line, and use ONLY the built-in command line.
1673 This is used to work around broken boot loaders. This should
1674 be set to 'N' under normal conditions.
1678 config ARCH_ENABLE_MEMORY_HOTPLUG
1680 depends on X86_64 || (X86_32 && HIGHMEM)
1682 config ARCH_ENABLE_MEMORY_HOTREMOVE
1684 depends on MEMORY_HOTPLUG
1686 config HAVE_ARCH_EARLY_PFN_TO_NID
1690 menu "Power management and ACPI options"
1692 config ARCH_HIBERNATION_HEADER
1694 depends on X86_64 && HIBERNATION
1696 source "kernel/power/Kconfig"
1698 source "drivers/acpi/Kconfig"
1700 source "drivers/sfi/Kconfig"
1705 depends on APM || APM_MODULE
1708 tristate "APM (Advanced Power Management) BIOS support"
1709 depends on X86_32 && PM_SLEEP
1711 APM is a BIOS specification for saving power using several different
1712 techniques. This is mostly useful for battery powered laptops with
1713 APM compliant BIOSes. If you say Y here, the system time will be
1714 reset after a RESUME operation, the /proc/apm device will provide
1715 battery status information, and user-space programs will receive
1716 notification of APM "events" (e.g. battery status change).
1718 If you select "Y" here, you can disable actual use of the APM
1719 BIOS by passing the "apm=off" option to the kernel at boot time.
1721 Note that the APM support is almost completely disabled for
1722 machines with more than one CPU.
1724 In order to use APM, you will need supporting software. For location
1725 and more information, read <file:Documentation/power/pm.txt> and the
1726 Battery Powered Linux mini-HOWTO, available from
1727 <http://www.tldp.org/docs.html#howto>.
1729 This driver does not spin down disk drives (see the hdparm(8)
1730 manpage ("man 8 hdparm") for that), and it doesn't turn off
1731 VESA-compliant "green" monitors.
1733 This driver does not support the TI 4000M TravelMate and the ACER
1734 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1735 desktop machines also don't have compliant BIOSes, and this driver
1736 may cause those machines to panic during the boot phase.
1738 Generally, if you don't have a battery in your machine, there isn't
1739 much point in using this driver and you should say N. If you get
1740 random kernel OOPSes or reboots that don't seem to be related to
1741 anything, try disabling/enabling this option (or disabling/enabling
1744 Some other things you should try when experiencing seemingly random,
1747 1) make sure that you have enough swap space and that it is
1749 2) pass the "no-hlt" option to the kernel
1750 3) switch on floating point emulation in the kernel and pass
1751 the "no387" option to the kernel
1752 4) pass the "floppy=nodma" option to the kernel
1753 5) pass the "mem=4M" option to the kernel (thereby disabling
1754 all but the first 4 MB of RAM)
1755 6) make sure that the CPU is not over clocked.
1756 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1757 8) disable the cache from your BIOS settings
1758 9) install a fan for the video card or exchange video RAM
1759 10) install a better fan for the CPU
1760 11) exchange RAM chips
1761 12) exchange the motherboard.
1763 To compile this driver as a module, choose M here: the
1764 module will be called apm.
1768 config APM_IGNORE_USER_SUSPEND
1769 bool "Ignore USER SUSPEND"
1771 This option will ignore USER SUSPEND requests. On machines with a
1772 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1773 series notebooks, it is necessary to say Y because of a BIOS bug.
1775 config APM_DO_ENABLE
1776 bool "Enable PM at boot time"
1778 Enable APM features at boot time. From page 36 of the APM BIOS
1779 specification: "When disabled, the APM BIOS does not automatically
1780 power manage devices, enter the Standby State, enter the Suspend
1781 State, or take power saving steps in response to CPU Idle calls."
1782 This driver will make CPU Idle calls when Linux is idle (unless this
1783 feature is turned off -- see "Do CPU IDLE calls", below). This
1784 should always save battery power, but more complicated APM features
1785 will be dependent on your BIOS implementation. You may need to turn
1786 this option off if your computer hangs at boot time when using APM
1787 support, or if it beeps continuously instead of suspending. Turn
1788 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1789 T400CDT. This is off by default since most machines do fine without
1793 bool "Make CPU Idle calls when idle"
1795 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1796 On some machines, this can activate improved power savings, such as
1797 a slowed CPU clock rate, when the machine is idle. These idle calls
1798 are made after the idle loop has run for some length of time (e.g.,
1799 333 mS). On some machines, this will cause a hang at boot time or
1800 whenever the CPU becomes idle. (On machines with more than one CPU,
1801 this option does nothing.)
1803 config APM_DISPLAY_BLANK
1804 bool "Enable console blanking using APM"
1806 Enable console blanking using the APM. Some laptops can use this to
1807 turn off the LCD backlight when the screen blanker of the Linux
1808 virtual console blanks the screen. Note that this is only used by
1809 the virtual console screen blanker, and won't turn off the backlight
1810 when using the X Window system. This also doesn't have anything to
1811 do with your VESA-compliant power-saving monitor. Further, this
1812 option doesn't work for all laptops -- it might not turn off your
1813 backlight at all, or it might print a lot of errors to the console,
1814 especially if you are using gpm.
1816 config APM_ALLOW_INTS
1817 bool "Allow interrupts during APM BIOS calls"
1819 Normally we disable external interrupts while we are making calls to
1820 the APM BIOS as a measure to lessen the effects of a badly behaving
1821 BIOS implementation. The BIOS should reenable interrupts if it
1822 needs to. Unfortunately, some BIOSes do not -- especially those in
1823 many of the newer IBM Thinkpads. If you experience hangs when you
1824 suspend, try setting this to Y. Otherwise, say N.
1828 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1830 source "drivers/cpuidle/Kconfig"
1832 source "drivers/idle/Kconfig"
1837 menu "Bus options (PCI etc.)"
1842 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1844 Find out whether you have a PCI motherboard. PCI is the name of a
1845 bus system, i.e. the way the CPU talks to the other stuff inside
1846 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1847 VESA. If you have PCI, say Y, otherwise N.
1850 prompt "PCI access mode"
1851 depends on X86_32 && PCI
1854 On PCI systems, the BIOS can be used to detect the PCI devices and
1855 determine their configuration. However, some old PCI motherboards
1856 have BIOS bugs and may crash if this is done. Also, some embedded
1857 PCI-based systems don't have any BIOS at all. Linux can also try to
1858 detect the PCI hardware directly without using the BIOS.
1860 With this option, you can specify how Linux should detect the
1861 PCI devices. If you choose "BIOS", the BIOS will be used,
1862 if you choose "Direct", the BIOS won't be used, and if you
1863 choose "MMConfig", then PCI Express MMCONFIG will be used.
1864 If you choose "Any", the kernel will try MMCONFIG, then the
1865 direct access method and falls back to the BIOS if that doesn't
1866 work. If unsure, go with the default, which is "Any".
1871 config PCI_GOMMCONFIG
1888 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1890 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1893 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1897 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1901 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1908 bool "Support mmconfig PCI config space access"
1909 depends on X86_64 && PCI && ACPI
1912 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1913 depends on PCI_MSI && ACPI && EXPERIMENTAL
1915 DMA remapping (DMAR) devices support enables independent address
1916 translations for Direct Memory Access (DMA) from devices.
1917 These DMA remapping devices are reported via ACPI tables
1918 and include PCI device scope covered by these DMA
1921 config DMAR_DEFAULT_ON
1923 prompt "Enable DMA Remapping Devices by default"
1926 Selecting this option will enable a DMAR device at boot time if
1927 one is found. If this option is not selected, DMAR support can
1928 be enabled by passing intel_iommu=on to the kernel. It is
1929 recommended you say N here while the DMAR code remains
1932 config DMAR_BROKEN_GFX_WA
1934 prompt "Workaround broken graphics drivers (going away soon)"
1935 depends on DMAR && BROKEN
1937 Current Graphics drivers tend to use physical address
1938 for DMA and avoid using DMA APIs. Setting this config
1939 option permits the IOMMU driver to set a unity map for
1940 all the OS-visible memory. Hence the driver can continue
1941 to use physical addresses for DMA, at least until this
1942 option is removed in the 2.6.32 kernel.
1944 config DMAR_FLOPPY_WA
1948 Floppy disk drivers are known to bypass DMA API calls
1949 thereby failing to work when IOMMU is enabled. This
1950 workaround will setup a 1:1 mapping for the first
1951 16MiB to make floppy (an ISA device) work.
1954 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1955 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1957 Supports Interrupt remapping for IO-APIC and MSI devices.
1958 To use x2apic mode in the CPU's which support x2APIC enhancements or
1959 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1961 source "drivers/pci/pcie/Kconfig"
1963 source "drivers/pci/Kconfig"
1965 # x86_64 have no ISA slots, but do have ISA-style DMA.
1974 Find out whether you have ISA slots on your motherboard. ISA is the
1975 name of a bus system, i.e. the way the CPU talks to the other stuff
1976 inside your box. Other bus systems are PCI, EISA, MicroChannel
1977 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1978 newer boards don't support it. If you have ISA, say Y, otherwise N.
1984 The Extended Industry Standard Architecture (EISA) bus was
1985 developed as an open alternative to the IBM MicroChannel bus.
1987 The EISA bus provided some of the features of the IBM MicroChannel
1988 bus while maintaining backward compatibility with cards made for
1989 the older ISA bus. The EISA bus saw limited use between 1988 and
1990 1995 when it was made obsolete by the PCI bus.
1992 Say Y here if you are building a kernel for an EISA-based machine.
1996 source "drivers/eisa/Kconfig"
2001 MicroChannel Architecture is found in some IBM PS/2 machines and
2002 laptops. It is a bus system similar to PCI or ISA. See
2003 <file:Documentation/mca.txt> (and especially the web page given
2004 there) before attempting to build an MCA bus kernel.
2006 source "drivers/mca/Kconfig"
2009 tristate "NatSemi SCx200 support"
2011 This provides basic support for National Semiconductor's
2012 (now AMD's) Geode processors. The driver probes for the
2013 PCI-IDs of several on-chip devices, so its a good dependency
2014 for other scx200_* drivers.
2016 If compiled as a module, the driver is named scx200.
2018 config SCx200HR_TIMER
2019 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2020 depends on SCx200 && GENERIC_TIME
2023 This driver provides a clocksource built upon the on-chip
2024 27MHz high-resolution timer. Its also a workaround for
2025 NSC Geode SC-1100's buggy TSC, which loses time when the
2026 processor goes idle (as is done by the scheduler). The
2027 other workaround is idle=poll boot option.
2030 bool "One Laptop Per Child support"
2034 Add support for detecting the unique features of the OLPC
2041 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2043 source "drivers/pcmcia/Kconfig"
2045 source "drivers/pci/hotplug/Kconfig"
2050 menu "Executable file formats / Emulations"
2052 source "fs/Kconfig.binfmt"
2054 config IA32_EMULATION
2055 bool "IA32 Emulation"
2057 select COMPAT_BINFMT_ELF
2059 Include code to run 32-bit programs under a 64-bit kernel. You should
2060 likely turn this on, unless you're 100% sure that you don't have any
2061 32-bit programs left.
2064 tristate "IA32 a.out support"
2065 depends on IA32_EMULATION
2067 Support old a.out binaries in the 32bit emulation.
2071 depends on IA32_EMULATION
2073 config COMPAT_FOR_U64_ALIGNMENT
2077 config SYSVIPC_COMPAT
2079 depends on COMPAT && SYSVIPC
2084 config HAVE_ATOMIC_IOMAP
2088 source "net/Kconfig"
2090 source "drivers/Kconfig"
2092 source "drivers/firmware/Kconfig"
2096 source "arch/x86/Kconfig.debug"
2098 source "security/Kconfig"
2100 source "crypto/Kconfig"
2102 source "arch/x86/kvm/Kconfig"
2104 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob