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)
29 select HAVE_IOREMAP_PROT
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_C_RECORDMCOUNT
38 select HAVE_DYNAMIC_FTRACE
39 select HAVE_FUNCTION_TRACER
40 select HAVE_FUNCTION_GRAPH_TRACER
41 select HAVE_FUNCTION_GRAPH_FP_TEST
42 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
43 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
44 select HAVE_SYSCALL_TRACEPOINTS
47 select HAVE_ARCH_TRACEHOOK
48 select HAVE_GENERIC_DMA_COHERENT if X86_32
49 select HAVE_EFFICIENT_UNALIGNED_ACCESS
50 select USER_STACKTRACE_SUPPORT
51 select HAVE_REGS_AND_STACK_ACCESS_API
52 select HAVE_DMA_API_DEBUG
53 select HAVE_KERNEL_GZIP
54 select HAVE_KERNEL_BZIP2
55 select HAVE_KERNEL_LZMA
56 select HAVE_KERNEL_LZO
57 select HAVE_HW_BREAKPOINT
58 select HAVE_MIXED_BREAKPOINTS_REGS
60 select HAVE_PERF_EVENTS_NMI
62 select HAVE_ARCH_KMEMCHECK
63 select HAVE_USER_RETURN_NOTIFIER
64 select HAVE_ARCH_JUMP_LABEL
65 select HAVE_TEXT_POKE_SMP
67 config INSTRUCTION_DECODER
68 def_bool (KPROBES || PERF_EVENTS)
72 default "elf32-i386" if X86_32
73 default "elf64-x86-64" if X86_64
77 default "arch/x86/configs/i386_defconfig" if X86_32
78 default "arch/x86/configs/x86_64_defconfig" if X86_64
80 config GENERIC_CMOS_UPDATE
83 config CLOCKSOURCE_WATCHDOG
86 config GENERIC_CLOCKEVENTS
89 config GENERIC_CLOCKEVENTS_BROADCAST
91 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
93 config LOCKDEP_SUPPORT
96 config STACKTRACE_SUPPORT
99 config HAVE_LATENCYTOP_SUPPORT
111 config NEED_DMA_MAP_STATE
112 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
114 config NEED_SG_DMA_LENGTH
117 config GENERIC_ISA_DMA
126 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
128 config GENERIC_BUG_RELATIVE_POINTERS
131 config GENERIC_HWEIGHT
137 config ARCH_MAY_HAVE_PC_FDC
140 config RWSEM_GENERIC_SPINLOCK
143 config RWSEM_XCHGADD_ALGORITHM
146 config ARCH_HAS_CPU_IDLE_WAIT
149 config GENERIC_CALIBRATE_DELAY
152 config GENERIC_TIME_VSYSCALL
156 config ARCH_HAS_CPU_RELAX
159 config ARCH_HAS_DEFAULT_IDLE
162 config ARCH_HAS_CACHE_LINE_SIZE
165 config HAVE_SETUP_PER_CPU_AREA
168 config NEED_PER_CPU_EMBED_FIRST_CHUNK
171 config NEED_PER_CPU_PAGE_FIRST_CHUNK
174 config HAVE_CPUMASK_OF_CPU_MAP
177 config ARCH_HIBERNATION_POSSIBLE
180 config ARCH_SUSPEND_POSSIBLE
187 config ARCH_POPULATES_NODE_MAP
194 config ARCH_SUPPORTS_OPTIMIZED_INLINING
197 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
200 config HAVE_EARLY_RES
203 config HAVE_INTEL_TXT
205 depends on EXPERIMENTAL && DMAR && ACPI
207 # Use the generic interrupt handling code in kernel/irq/:
208 config GENERIC_HARDIRQS
211 config GENERIC_HARDIRQS_NO__DO_IRQ
214 config GENERIC_IRQ_PROBE
217 config GENERIC_PENDING_IRQ
219 depends on GENERIC_HARDIRQS && SMP
221 config USE_GENERIC_SMP_HELPERS
227 depends on X86_32 && SMP
231 depends on X86_64 && SMP
237 config X86_TRAMPOLINE
239 depends on SMP || (64BIT && ACPI_SLEEP)
241 config X86_32_LAZY_GS
243 depends on X86_32 && !CC_STACKPROTECTOR
245 config ARCH_HWEIGHT_CFLAGS
247 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
248 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
253 config ARCH_CPU_PROBE_RELEASE
255 depends on HOTPLUG_CPU
257 source "init/Kconfig"
258 source "kernel/Kconfig.freezer"
260 menu "Processor type and features"
262 source "kernel/time/Kconfig"
265 bool "Symmetric multi-processing support"
267 This enables support for systems with more than one CPU. If you have
268 a system with only one CPU, like most personal computers, say N. If
269 you have a system with more than one CPU, say Y.
271 If you say N here, the kernel will run on single and multiprocessor
272 machines, but will use only one CPU of a multiprocessor machine. If
273 you say Y here, the kernel will run on many, but not all,
274 singleprocessor machines. On a singleprocessor machine, the kernel
275 will run faster if you say N here.
277 Note that if you say Y here and choose architecture "586" or
278 "Pentium" under "Processor family", the kernel will not work on 486
279 architectures. Similarly, multiprocessor kernels for the "PPro"
280 architecture may not work on all Pentium based boards.
282 People using multiprocessor machines who say Y here should also say
283 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
284 Management" code will be disabled if you say Y here.
286 See also <file:Documentation/i386/IO-APIC.txt>,
287 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
288 <http://www.tldp.org/docs.html#howto>.
290 If you don't know what to do here, say N.
293 bool "Support x2apic"
294 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
296 This enables x2apic support on CPUs that have this feature.
298 This allows 32-bit apic IDs (so it can support very large systems),
299 and accesses the local apic via MSRs not via mmio.
301 If you don't know what to do here, say N.
304 bool "Support sparse irq numbering"
305 depends on PCI_MSI || HT_IRQ
307 This enables support for sparse irqs. This is useful for distro
308 kernels that want to define a high CONFIG_NR_CPUS value but still
309 want to have low kernel memory footprint on smaller machines.
311 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
312 out the irq_desc[] array in a more NUMA-friendly way. )
314 If you don't know what to do here, say N.
318 depends on SPARSE_IRQ && NUMA
321 bool "Enable MPS table" if ACPI
323 depends on X86_LOCAL_APIC
325 For old smp systems that do not have proper acpi support. Newer systems
326 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
329 bool "Support for big SMP systems with more than 8 CPUs"
330 depends on X86_32 && SMP
332 This option is needed for the systems that have more than 8 CPUs
335 config X86_EXTENDED_PLATFORM
336 bool "Support for extended (non-PC) x86 platforms"
339 If you disable this option then the kernel will only support
340 standard PC platforms. (which covers the vast majority of
343 If you enable this option then you'll be able to select support
344 for the following (non-PC) 32 bit x86 platforms:
348 SGI 320/540 (Visual Workstation)
349 Summit/EXA (IBM x440)
350 Unisys ES7000 IA32 series
351 Moorestown MID devices
353 If you have one of these systems, or if you want to build a
354 generic distribution kernel, say Y here - otherwise say N.
358 config X86_EXTENDED_PLATFORM
359 bool "Support for extended (non-PC) x86 platforms"
362 If you disable this option then the kernel will only support
363 standard PC platforms. (which covers the vast majority of
366 If you enable this option then you'll be able to select support
367 for the following (non-PC) 64 bit x86 platforms:
371 If you have one of these systems, or if you want to build a
372 generic distribution kernel, say Y here - otherwise say N.
374 # This is an alphabetically sorted list of 64 bit extended platforms
375 # Please maintain the alphabetic order if and when there are additions
380 depends on X86_64 && PCI
381 depends on X86_EXTENDED_PLATFORM
383 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
384 supposed to run on these EM64T-based machines. Only choose this option
385 if you have one of these machines.
388 bool "SGI Ultraviolet"
390 depends on X86_EXTENDED_PLATFORM
392 depends on X86_X2APIC
394 This option is needed in order to support SGI Ultraviolet systems.
395 If you don't have one of these, you should say N here.
397 # Following is an alphabetically sorted list of 32 bit extended platforms
398 # Please maintain the alphabetic order if and when there are additions
403 depends on X86_EXTENDED_PLATFORM
405 Select this for an AMD Elan processor.
407 Do not use this option for K6/Athlon/Opteron processors!
409 If unsure, choose "PC-compatible" instead.
412 bool "Moorestown MID platform"
416 depends on X86_EXTENDED_PLATFORM
417 depends on X86_IO_APIC
420 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
421 Internet Device(MID) platform. Moorestown consists of two chips:
422 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
423 Unlike standard x86 PCs, Moorestown does not have many legacy devices
424 nor standard legacy replacement devices/features. e.g. Moorestown does
425 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
428 bool "RDC R-321x SoC"
430 depends on X86_EXTENDED_PLATFORM
432 select X86_REBOOTFIXUPS
434 This option is needed for RDC R-321x system-on-chip, also known
436 If you don't have one of these chips, you should say N here.
438 config X86_32_NON_STANDARD
439 bool "Support non-standard 32-bit SMP architectures"
440 depends on X86_32 && SMP
441 depends on X86_EXTENDED_PLATFORM
443 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
444 subarchitectures. It is intended for a generic binary kernel.
445 if you select them all, kernel will probe it one by one. and will
448 # Alphabetically sorted list of Non standard 32 bit platforms
451 bool "NUMAQ (IBM/Sequent)"
452 depends on X86_32_NON_STANDARD
457 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
458 NUMA multiquad box. This changes the way that processors are
459 bootstrapped, and uses Clustered Logical APIC addressing mode instead
460 of Flat Logical. You will need a new lynxer.elf file to flash your
461 firmware with - send email to <Martin.Bligh@us.ibm.com>.
463 config X86_SUPPORTS_MEMORY_FAILURE
465 # MCE code calls memory_failure():
467 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
468 depends on !X86_NUMAQ
469 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
470 depends on X86_64 || !SPARSEMEM
471 select ARCH_SUPPORTS_MEMORY_FAILURE
474 bool "SGI 320/540 (Visual Workstation)"
475 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
476 depends on X86_32_NON_STANDARD
478 The SGI Visual Workstation series is an IA32-based workstation
479 based on SGI systems chips with some legacy PC hardware attached.
481 Say Y here to create a kernel to run on the SGI 320 or 540.
483 A kernel compiled for the Visual Workstation will run on general
484 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
487 bool "Summit/EXA (IBM x440)"
488 depends on X86_32_NON_STANDARD
490 This option is needed for IBM systems that use the Summit/EXA chipset.
491 In particular, it is needed for the x440.
494 bool "Unisys ES7000 IA32 series"
495 depends on X86_32_NON_STANDARD && X86_BIGSMP
497 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
498 supposed to run on an IA32-based Unisys ES7000 system.
500 config SCHED_OMIT_FRAME_POINTER
502 prompt "Single-depth WCHAN output"
505 Calculate simpler /proc/<PID>/wchan values. If this option
506 is disabled then wchan values will recurse back to the
507 caller function. This provides more accurate wchan values,
508 at the expense of slightly more scheduling overhead.
510 If in doubt, say "Y".
512 menuconfig PARAVIRT_GUEST
513 bool "Paravirtualized guest support"
515 Say Y here to get to see options related to running Linux under
516 various hypervisors. This option alone does not add any kernel code.
518 If you say N, all options in this submenu will be skipped and disabled.
522 source "arch/x86/xen/Kconfig"
525 bool "VMI Guest support (DEPRECATED)"
529 VMI provides a paravirtualized interface to the VMware ESX server
530 (it could be used by other hypervisors in theory too, but is not
531 at the moment), by linking the kernel to a GPL-ed ROM module
532 provided by the hypervisor.
534 As of September 2009, VMware has started a phased retirement
535 of this feature from VMware's products. Please see
536 feature-removal-schedule.txt for details. If you are
537 planning to enable this option, please note that you cannot
538 live migrate a VMI enabled VM to a future VMware product,
539 which doesn't support VMI. So if you expect your kernel to
540 seamlessly migrate to newer VMware products, keep this
544 bool "KVM paravirtualized clock"
546 select PARAVIRT_CLOCK
548 Turning on this option will allow you to run a paravirtualized clock
549 when running over the KVM hypervisor. Instead of relying on a PIT
550 (or probably other) emulation by the underlying device model, the host
551 provides the guest with timing infrastructure such as time of day, and
555 bool "KVM Guest support"
558 This option enables various optimizations for running under the KVM
561 source "arch/x86/lguest/Kconfig"
564 bool "Enable paravirtualization code"
566 This changes the kernel so it can modify itself when it is run
567 under a hypervisor, potentially improving performance significantly
568 over full virtualization. However, when run without a hypervisor
569 the kernel is theoretically slower and slightly larger.
571 config PARAVIRT_SPINLOCKS
572 bool "Paravirtualization layer for spinlocks"
573 depends on PARAVIRT && SMP && EXPERIMENTAL
575 Paravirtualized spinlocks allow a pvops backend to replace the
576 spinlock implementation with something virtualization-friendly
577 (for example, block the virtual CPU rather than spinning).
579 Unfortunately the downside is an up to 5% performance hit on
580 native kernels, with various workloads.
582 If you are unsure how to answer this question, answer N.
584 config PARAVIRT_CLOCK
589 config PARAVIRT_DEBUG
590 bool "paravirt-ops debugging"
591 depends on PARAVIRT && DEBUG_KERNEL
593 Enable to debug paravirt_ops internals. Specifically, BUG if
594 a paravirt_op is missing when it is called.
598 bool "Disable Bootmem code"
600 Use early_res directly instead of bootmem before slab is ready.
601 - allocator (buddy) [generic]
602 - early allocator (bootmem) [generic]
603 - very early allocator (reserve_early*()) [x86]
604 - very very early allocator (early brk model) [x86]
605 So reduce one layer between early allocator to final allocator
611 This option adds a kernel parameter 'memtest', which allows memtest
613 memtest=0, mean disabled; -- default
614 memtest=1, mean do 1 test pattern;
616 memtest=4, mean do 4 test patterns.
617 If you are unsure how to answer this question, answer N.
619 config X86_SUMMIT_NUMA
621 depends on X86_32 && NUMA && X86_32_NON_STANDARD
623 config X86_CYCLONE_TIMER
625 depends on X86_32_NON_STANDARD
627 source "arch/x86/Kconfig.cpu"
631 prompt "HPET Timer Support" if X86_32
633 Use the IA-PC HPET (High Precision Event Timer) to manage
634 time in preference to the PIT and RTC, if a HPET is
636 HPET is the next generation timer replacing legacy 8254s.
637 The HPET provides a stable time base on SMP
638 systems, unlike the TSC, but it is more expensive to access,
639 as it is off-chip. You can find the HPET spec at
640 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
642 You can safely choose Y here. However, HPET will only be
643 activated if the platform and the BIOS support this feature.
644 Otherwise the 8254 will be used for timing services.
646 Choose N to continue using the legacy 8254 timer.
648 config HPET_EMULATE_RTC
650 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
654 prompt "Langwell APB Timer Support" if X86_MRST
656 APB timer is the replacement for 8254, HPET on X86 MID platforms.
657 The APBT provides a stable time base on SMP
658 systems, unlike the TSC, but it is more expensive to access,
659 as it is off-chip. APB timers are always running regardless of CPU
660 C states, they are used as per CPU clockevent device when possible.
662 # Mark as embedded because too many people got it wrong.
663 # The code disables itself when not needed.
666 bool "Enable DMI scanning" if EMBEDDED
668 Enabled scanning of DMI to identify machine quirks. Say Y
669 here unless you have verified that your setup is not
670 affected by entries in the DMI blacklist. Required by PNP
674 bool "GART IOMMU support" if EMBEDDED
677 depends on X86_64 && PCI && K8_NB
679 Support for full DMA access of devices with 32bit memory access only
680 on systems with more than 3GB. This is usually needed for USB,
681 sound, many IDE/SATA chipsets and some other devices.
682 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
683 based hardware IOMMU and a software bounce buffer based IOMMU used
684 on Intel systems and as fallback.
685 The code is only active when needed (enough memory and limited
686 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
690 bool "IBM Calgary IOMMU support"
692 depends on X86_64 && PCI && EXPERIMENTAL
694 Support for hardware IOMMUs in IBM's xSeries x366 and x460
695 systems. Needed to run systems with more than 3GB of memory
696 properly with 32-bit PCI devices that do not support DAC
697 (Double Address Cycle). Calgary also supports bus level
698 isolation, where all DMAs pass through the IOMMU. This
699 prevents them from going anywhere except their intended
700 destination. This catches hard-to-find kernel bugs and
701 mis-behaving drivers and devices that do not use the DMA-API
702 properly to set up their DMA buffers. The IOMMU can be
703 turned off at boot time with the iommu=off parameter.
704 Normally the kernel will make the right choice by itself.
707 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
709 prompt "Should Calgary be enabled by default?"
710 depends on CALGARY_IOMMU
712 Should Calgary be enabled by default? if you choose 'y', Calgary
713 will be used (if it exists). If you choose 'n', Calgary will not be
714 used even if it exists. If you choose 'n' and would like to use
715 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
719 bool "AMD IOMMU support"
722 depends on X86_64 && PCI && ACPI
724 With this option you can enable support for AMD IOMMU hardware in
725 your system. An IOMMU is a hardware component which provides
726 remapping of DMA memory accesses from devices. With an AMD IOMMU you
727 can isolate the the DMA memory of different devices and protect the
728 system from misbehaving device drivers or hardware.
730 You can find out if your system has an AMD IOMMU if you look into
731 your BIOS for an option to enable it or if you have an IVRS ACPI
734 config AMD_IOMMU_STATS
735 bool "Export AMD IOMMU statistics to debugfs"
739 This option enables code in the AMD IOMMU driver to collect various
740 statistics about whats happening in the driver and exports that
741 information to userspace via debugfs.
744 # need this always selected by IOMMU for the VIA workaround
748 Support for software bounce buffers used on x86-64 systems
749 which don't have a hardware IOMMU (e.g. the current generation
750 of Intel's x86-64 CPUs). Using this PCI devices which can only
751 access 32-bits of memory can be used on systems with more than
752 3 GB of memory. If unsure, say Y.
755 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
758 def_bool (AMD_IOMMU || DMAR)
761 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
762 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
763 select CPUMASK_OFFSTACK
765 Enable maximum number of CPUS and NUMA Nodes for this architecture.
769 int "Maximum number of CPUs" if SMP && !MAXSMP
770 range 2 8 if SMP && X86_32 && !X86_BIGSMP
771 range 2 512 if SMP && !MAXSMP
773 default "4096" if MAXSMP
774 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
777 This allows you to specify the maximum number of CPUs which this
778 kernel will support. The maximum supported value is 512 and the
779 minimum value which makes sense is 2.
781 This is purely to save memory - each supported CPU adds
782 approximately eight kilobytes to the kernel image.
785 bool "SMT (Hyperthreading) scheduler support"
788 SMT scheduler support improves the CPU scheduler's decision making
789 when dealing with Intel Pentium 4 chips with HyperThreading at a
790 cost of slightly increased overhead in some places. If unsure say
795 prompt "Multi-core scheduler support"
798 Multi-core scheduler support improves the CPU scheduler's decision
799 making when dealing with multi-core CPU chips at a cost of slightly
800 increased overhead in some places. If unsure say N here.
802 source "kernel/Kconfig.preempt"
805 bool "Local APIC support on uniprocessors"
806 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
808 A local APIC (Advanced Programmable Interrupt Controller) is an
809 integrated interrupt controller in the CPU. If you have a single-CPU
810 system which has a processor with a local APIC, you can say Y here to
811 enable and use it. If you say Y here even though your machine doesn't
812 have a local APIC, then the kernel will still run with no slowdown at
813 all. The local APIC supports CPU-generated self-interrupts (timer,
814 performance counters), and the NMI watchdog which detects hard
818 bool "IO-APIC support on uniprocessors"
819 depends on X86_UP_APIC
821 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
822 SMP-capable replacement for PC-style interrupt controllers. Most
823 SMP systems and many recent uniprocessor systems have one.
825 If you have a single-CPU system with an IO-APIC, you can say Y here
826 to use it. If you say Y here even though your machine doesn't have
827 an IO-APIC, then the kernel will still run with no slowdown at all.
829 config X86_LOCAL_APIC
831 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
835 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
837 config X86_VISWS_APIC
839 depends on X86_32 && X86_VISWS
841 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
842 bool "Reroute for broken boot IRQs"
843 depends on X86_IO_APIC
845 This option enables a workaround that fixes a source of
846 spurious interrupts. This is recommended when threaded
847 interrupt handling is used on systems where the generation of
848 superfluous "boot interrupts" cannot be disabled.
850 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
851 entry in the chipset's IO-APIC is masked (as, e.g. the RT
852 kernel does during interrupt handling). On chipsets where this
853 boot IRQ generation cannot be disabled, this workaround keeps
854 the original IRQ line masked so that only the equivalent "boot
855 IRQ" is delivered to the CPUs. The workaround also tells the
856 kernel to set up the IRQ handler on the boot IRQ line. In this
857 way only one interrupt is delivered to the kernel. Otherwise
858 the spurious second interrupt may cause the kernel to bring
859 down (vital) interrupt lines.
861 Only affects "broken" chipsets. Interrupt sharing may be
862 increased on these systems.
865 bool "Machine Check / overheating reporting"
867 Machine Check support allows the processor to notify the
868 kernel if it detects a problem (e.g. overheating, data corruption).
869 The action the kernel takes depends on the severity of the problem,
870 ranging from warning messages to halting the machine.
874 prompt "Intel MCE features"
875 depends on X86_MCE && X86_LOCAL_APIC
877 Additional support for intel specific MCE features such as
882 prompt "AMD MCE features"
883 depends on X86_MCE && X86_LOCAL_APIC
885 Additional support for AMD specific MCE features such as
886 the DRAM Error Threshold.
888 config X86_ANCIENT_MCE
889 bool "Support for old Pentium 5 / WinChip machine checks"
890 depends on X86_32 && X86_MCE
892 Include support for machine check handling on old Pentium 5 or WinChip
893 systems. These typically need to be enabled explicitely on the command
896 config X86_MCE_THRESHOLD
897 depends on X86_MCE_AMD || X86_MCE_INTEL
900 config X86_MCE_INJECT
902 tristate "Machine check injector support"
904 Provide support for injecting machine checks for testing purposes.
905 If you don't know what a machine check is and you don't do kernel
906 QA it is safe to say n.
908 config X86_THERMAL_VECTOR
910 depends on X86_MCE_INTEL
913 bool "Enable VM86 support" if EMBEDDED
917 This option is required by programs like DOSEMU to run 16-bit legacy
918 code on X86 processors. It also may be needed by software like
919 XFree86 to initialize some video cards via BIOS. Disabling this
920 option saves about 6k.
923 tristate "Toshiba Laptop support"
926 This adds a driver to safely access the System Management Mode of
927 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
928 not work on models with a Phoenix BIOS. The System Management Mode
929 is used to set the BIOS and power saving options on Toshiba portables.
931 For information on utilities to make use of this driver see the
932 Toshiba Linux utilities web site at:
933 <http://www.buzzard.org.uk/toshiba/>.
935 Say Y if you intend to run this kernel on a Toshiba portable.
939 tristate "Dell laptop support"
941 This adds a driver to safely access the System Management Mode
942 of the CPU on the Dell Inspiron 8000. The System Management Mode
943 is used to read cpu temperature and cooling fan status and to
944 control the fans on the I8K portables.
946 This driver has been tested only on the Inspiron 8000 but it may
947 also work with other Dell laptops. You can force loading on other
948 models by passing the parameter `force=1' to the module. Use at
951 For information on utilities to make use of this driver see the
952 I8K Linux utilities web site at:
953 <http://people.debian.org/~dz/i8k/>
955 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
958 config X86_REBOOTFIXUPS
959 bool "Enable X86 board specific fixups for reboot"
962 This enables chipset and/or board specific fixups to be done
963 in order to get reboot to work correctly. This is only needed on
964 some combinations of hardware and BIOS. The symptom, for which
965 this config is intended, is when reboot ends with a stalled/hung
968 Currently, the only fixup is for the Geode machines using
969 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
971 Say Y if you want to enable the fixup. Currently, it's safe to
972 enable this option even if you don't need it.
976 tristate "/dev/cpu/microcode - microcode support"
979 If you say Y here, you will be able to update the microcode on
980 certain Intel and AMD processors. The Intel support is for the
981 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
982 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
983 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
984 You will obviously need the actual microcode binary data itself
985 which is not shipped with the Linux kernel.
987 This option selects the general module only, you need to select
988 at least one vendor specific module as well.
990 To compile this driver as a module, choose M here: the
991 module will be called microcode.
993 config MICROCODE_INTEL
994 bool "Intel microcode patch loading support"
999 This options enables microcode patch loading support for Intel
1002 For latest news and information on obtaining all the required
1003 Intel ingredients for this driver, check:
1004 <http://www.urbanmyth.org/microcode/>.
1006 config MICROCODE_AMD
1007 bool "AMD microcode patch loading support"
1008 depends on MICROCODE
1011 If you select this option, microcode patch loading support for AMD
1012 processors will be enabled.
1014 config MICROCODE_OLD_INTERFACE
1016 depends on MICROCODE
1019 tristate "/dev/cpu/*/msr - Model-specific register support"
1021 This device gives privileged processes access to the x86
1022 Model-Specific Registers (MSRs). It is a character device with
1023 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1024 MSR accesses are directed to a specific CPU on multi-processor
1028 tristate "/dev/cpu/*/cpuid - CPU information support"
1030 This device gives processes access to the x86 CPUID instruction to
1031 be executed on a specific processor. It is a character device
1032 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1036 prompt "High Memory Support"
1037 default HIGHMEM64G if X86_NUMAQ
1043 depends on !X86_NUMAQ
1045 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1046 However, the address space of 32-bit x86 processors is only 4
1047 Gigabytes large. That means that, if you have a large amount of
1048 physical memory, not all of it can be "permanently mapped" by the
1049 kernel. The physical memory that's not permanently mapped is called
1052 If you are compiling a kernel which will never run on a machine with
1053 more than 1 Gigabyte total physical RAM, answer "off" here (default
1054 choice and suitable for most users). This will result in a "3GB/1GB"
1055 split: 3GB are mapped so that each process sees a 3GB virtual memory
1056 space and the remaining part of the 4GB virtual memory space is used
1057 by the kernel to permanently map as much physical memory as
1060 If the machine has between 1 and 4 Gigabytes physical RAM, then
1063 If more than 4 Gigabytes is used then answer "64GB" here. This
1064 selection turns Intel PAE (Physical Address Extension) mode on.
1065 PAE implements 3-level paging on IA32 processors. PAE is fully
1066 supported by Linux, PAE mode is implemented on all recent Intel
1067 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1068 then the kernel will not boot on CPUs that don't support PAE!
1070 The actual amount of total physical memory will either be
1071 auto detected or can be forced by using a kernel command line option
1072 such as "mem=256M". (Try "man bootparam" or see the documentation of
1073 your boot loader (lilo or loadlin) about how to pass options to the
1074 kernel at boot time.)
1076 If unsure, say "off".
1080 depends on !X86_NUMAQ
1082 Select this if you have a 32-bit processor and between 1 and 4
1083 gigabytes of physical RAM.
1087 depends on !M386 && !M486
1090 Select this if you have a 32-bit processor and more than 4
1091 gigabytes of physical RAM.
1096 depends on EXPERIMENTAL
1097 prompt "Memory split" if EMBEDDED
1101 Select the desired split between kernel and user memory.
1103 If the address range available to the kernel is less than the
1104 physical memory installed, the remaining memory will be available
1105 as "high memory". Accessing high memory is a little more costly
1106 than low memory, as it needs to be mapped into the kernel first.
1107 Note that increasing the kernel address space limits the range
1108 available to user programs, making the address space there
1109 tighter. Selecting anything other than the default 3G/1G split
1110 will also likely make your kernel incompatible with binary-only
1113 If you are not absolutely sure what you are doing, leave this
1117 bool "3G/1G user/kernel split"
1118 config VMSPLIT_3G_OPT
1120 bool "3G/1G user/kernel split (for full 1G low memory)"
1122 bool "2G/2G user/kernel split"
1123 config VMSPLIT_2G_OPT
1125 bool "2G/2G user/kernel split (for full 2G low memory)"
1127 bool "1G/3G user/kernel split"
1132 default 0xB0000000 if VMSPLIT_3G_OPT
1133 default 0x80000000 if VMSPLIT_2G
1134 default 0x78000000 if VMSPLIT_2G_OPT
1135 default 0x40000000 if VMSPLIT_1G
1141 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1144 bool "PAE (Physical Address Extension) Support"
1145 depends on X86_32 && !HIGHMEM4G
1147 PAE is required for NX support, and furthermore enables
1148 larger swapspace support for non-overcommit purposes. It
1149 has the cost of more pagetable lookup overhead, and also
1150 consumes more pagetable space per process.
1152 config ARCH_PHYS_ADDR_T_64BIT
1153 def_bool X86_64 || X86_PAE
1155 config DIRECT_GBPAGES
1156 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1160 Allow the kernel linear mapping to use 1GB pages on CPUs that
1161 support it. This can improve the kernel's performance a tiny bit by
1162 reducing TLB pressure. If in doubt, say "Y".
1164 # Common NUMA Features
1166 bool "Numa Memory Allocation and Scheduler Support"
1168 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1169 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1171 Enable NUMA (Non Uniform Memory Access) support.
1173 The kernel will try to allocate memory used by a CPU on the
1174 local memory controller of the CPU and add some more
1175 NUMA awareness to the kernel.
1177 For 64-bit this is recommended if the system is Intel Core i7
1178 (or later), AMD Opteron, or EM64T NUMA.
1180 For 32-bit this is only needed on (rare) 32-bit-only platforms
1181 that support NUMA topologies, such as NUMAQ / Summit, or if you
1182 boot a 32-bit kernel on a 64-bit NUMA platform.
1184 Otherwise, you should say N.
1186 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1187 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1191 prompt "Old style AMD Opteron NUMA detection"
1192 depends on X86_64 && NUMA && PCI
1194 Enable K8 NUMA node topology detection. You should say Y here if
1195 you have a multi processor AMD K8 system. This uses an old
1196 method to read the NUMA configuration directly from the builtin
1197 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1198 instead, which also takes priority if both are compiled in.
1200 config X86_64_ACPI_NUMA
1202 prompt "ACPI NUMA detection"
1203 depends on X86_64 && NUMA && ACPI && PCI
1206 Enable ACPI SRAT based node topology detection.
1208 # Some NUMA nodes have memory ranges that span
1209 # other nodes. Even though a pfn is valid and
1210 # between a node's start and end pfns, it may not
1211 # reside on that node. See memmap_init_zone()
1213 config NODES_SPAN_OTHER_NODES
1215 depends on X86_64_ACPI_NUMA
1218 bool "NUMA emulation"
1219 depends on X86_64 && NUMA
1221 Enable NUMA emulation. A flat machine will be split
1222 into virtual nodes when booted with "numa=fake=N", where N is the
1223 number of nodes. This is only useful for debugging.
1226 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1228 default "10" if MAXSMP
1229 default "6" if X86_64
1230 default "4" if X86_NUMAQ
1232 depends on NEED_MULTIPLE_NODES
1234 Specify the maximum number of NUMA Nodes available on the target
1235 system. Increases memory reserved to accommodate various tables.
1237 config HAVE_ARCH_BOOTMEM
1239 depends on X86_32 && NUMA
1241 config ARCH_HAVE_MEMORY_PRESENT
1243 depends on X86_32 && DISCONTIGMEM
1245 config NEED_NODE_MEMMAP_SIZE
1247 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1249 config HAVE_ARCH_ALLOC_REMAP
1251 depends on X86_32 && NUMA
1253 config ARCH_FLATMEM_ENABLE
1255 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1257 config ARCH_DISCONTIGMEM_ENABLE
1259 depends on NUMA && X86_32
1261 config ARCH_DISCONTIGMEM_DEFAULT
1263 depends on NUMA && X86_32
1265 config ARCH_PROC_KCORE_TEXT
1267 depends on X86_64 && PROC_KCORE
1269 config ARCH_SPARSEMEM_DEFAULT
1273 config ARCH_SPARSEMEM_ENABLE
1275 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1276 select SPARSEMEM_STATIC if X86_32
1277 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1279 config ARCH_SELECT_MEMORY_MODEL
1281 depends on ARCH_SPARSEMEM_ENABLE
1283 config ARCH_MEMORY_PROBE
1285 depends on MEMORY_HOTPLUG
1287 config ILLEGAL_POINTER_VALUE
1290 default 0xdead000000000000 if X86_64
1295 bool "Allocate 3rd-level pagetables from highmem"
1298 The VM uses one page table entry for each page of physical memory.
1299 For systems with a lot of RAM, this can be wasteful of precious
1300 low memory. Setting this option will put user-space page table
1301 entries in high memory.
1303 config X86_CHECK_BIOS_CORRUPTION
1304 bool "Check for low memory corruption"
1306 Periodically check for memory corruption in low memory, which
1307 is suspected to be caused by BIOS. Even when enabled in the
1308 configuration, it is disabled at runtime. Enable it by
1309 setting "memory_corruption_check=1" on the kernel command
1310 line. By default it scans the low 64k of memory every 60
1311 seconds; see the memory_corruption_check_size and
1312 memory_corruption_check_period parameters in
1313 Documentation/kernel-parameters.txt to adjust this.
1315 When enabled with the default parameters, this option has
1316 almost no overhead, as it reserves a relatively small amount
1317 of memory and scans it infrequently. It both detects corruption
1318 and prevents it from affecting the running system.
1320 It is, however, intended as a diagnostic tool; if repeatable
1321 BIOS-originated corruption always affects the same memory,
1322 you can use memmap= to prevent the kernel from using that
1325 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1326 bool "Set the default setting of memory_corruption_check"
1327 depends on X86_CHECK_BIOS_CORRUPTION
1330 Set whether the default state of memory_corruption_check is
1333 config X86_RESERVE_LOW_64K
1334 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1337 Reserve the first 64K of physical RAM on BIOSes that are known
1338 to potentially corrupt that memory range. A numbers of BIOSes are
1339 known to utilize this area during suspend/resume, so it must not
1340 be used by the kernel.
1342 Set this to N if you are absolutely sure that you trust the BIOS
1343 to get all its memory reservations and usages right.
1345 If you have doubts about the BIOS (e.g. suspend/resume does not
1346 work or there's kernel crashes after certain hardware hotplug
1347 events) and it's not AMI or Phoenix, then you might want to enable
1348 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1349 corruption patterns.
1353 config MATH_EMULATION
1355 prompt "Math emulation" if X86_32
1357 Linux can emulate a math coprocessor (used for floating point
1358 operations) if you don't have one. 486DX and Pentium processors have
1359 a math coprocessor built in, 486SX and 386 do not, unless you added
1360 a 487DX or 387, respectively. (The messages during boot time can
1361 give you some hints here ["man dmesg"].) Everyone needs either a
1362 coprocessor or this emulation.
1364 If you don't have a math coprocessor, you need to say Y here; if you
1365 say Y here even though you have a coprocessor, the coprocessor will
1366 be used nevertheless. (This behavior can be changed with the kernel
1367 command line option "no387", which comes handy if your coprocessor
1368 is broken. Try "man bootparam" or see the documentation of your boot
1369 loader (lilo or loadlin) about how to pass options to the kernel at
1370 boot time.) This means that it is a good idea to say Y here if you
1371 intend to use this kernel on different machines.
1373 More information about the internals of the Linux math coprocessor
1374 emulation can be found in <file:arch/x86/math-emu/README>.
1376 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1377 kernel, it won't hurt.
1381 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1383 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1384 the Memory Type Range Registers (MTRRs) may be used to control
1385 processor access to memory ranges. This is most useful if you have
1386 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1387 allows bus write transfers to be combined into a larger transfer
1388 before bursting over the PCI/AGP bus. This can increase performance
1389 of image write operations 2.5 times or more. Saying Y here creates a
1390 /proc/mtrr file which may be used to manipulate your processor's
1391 MTRRs. Typically the X server should use this.
1393 This code has a reasonably generic interface so that similar
1394 control registers on other processors can be easily supported
1397 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1398 Registers (ARRs) which provide a similar functionality to MTRRs. For
1399 these, the ARRs are used to emulate the MTRRs.
1400 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1401 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1402 write-combining. All of these processors are supported by this code
1403 and it makes sense to say Y here if you have one of them.
1405 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1406 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1407 can lead to all sorts of problems, so it's good to say Y here.
1409 You can safely say Y even if your machine doesn't have MTRRs, you'll
1410 just add about 9 KB to your kernel.
1412 See <file:Documentation/x86/mtrr.txt> for more information.
1414 config MTRR_SANITIZER
1416 prompt "MTRR cleanup support"
1419 Convert MTRR layout from continuous to discrete, so X drivers can
1420 add writeback entries.
1422 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1423 The largest mtrr entry size for a continuous block can be set with
1428 config MTRR_SANITIZER_ENABLE_DEFAULT
1429 int "MTRR cleanup enable value (0-1)"
1432 depends on MTRR_SANITIZER
1434 Enable mtrr cleanup default value
1436 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1437 int "MTRR cleanup spare reg num (0-7)"
1440 depends on MTRR_SANITIZER
1442 mtrr cleanup spare entries default, it can be changed via
1443 mtrr_spare_reg_nr=N on the kernel command line.
1447 prompt "x86 PAT support" if EMBEDDED
1450 Use PAT attributes to setup page level cache control.
1452 PATs are the modern equivalents of MTRRs and are much more
1453 flexible than MTRRs.
1455 Say N here if you see bootup problems (boot crash, boot hang,
1456 spontaneous reboots) or a non-working video driver.
1460 config ARCH_USES_PG_UNCACHED
1465 bool "EFI runtime service support"
1468 This enables the kernel to use EFI runtime services that are
1469 available (such as the EFI variable services).
1471 This option is only useful on systems that have EFI firmware.
1472 In addition, you should use the latest ELILO loader available
1473 at <http://elilo.sourceforge.net> in order to take advantage
1474 of EFI runtime services. However, even with this option, the
1475 resultant kernel should continue to boot on existing non-EFI
1480 prompt "Enable seccomp to safely compute untrusted bytecode"
1482 This kernel feature is useful for number crunching applications
1483 that may need to compute untrusted bytecode during their
1484 execution. By using pipes or other transports made available to
1485 the process as file descriptors supporting the read/write
1486 syscalls, it's possible to isolate those applications in
1487 their own address space using seccomp. Once seccomp is
1488 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1489 and the task is only allowed to execute a few safe syscalls
1490 defined by each seccomp mode.
1492 If unsure, say Y. Only embedded should say N here.
1494 config CC_STACKPROTECTOR
1495 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1497 This option turns on the -fstack-protector GCC feature. This
1498 feature puts, at the beginning of functions, a canary value on
1499 the stack just before the return address, and validates
1500 the value just before actually returning. Stack based buffer
1501 overflows (that need to overwrite this return address) now also
1502 overwrite the canary, which gets detected and the attack is then
1503 neutralized via a kernel panic.
1505 This feature requires gcc version 4.2 or above, or a distribution
1506 gcc with the feature backported. Older versions are automatically
1507 detected and for those versions, this configuration option is
1508 ignored. (and a warning is printed during bootup)
1510 source kernel/Kconfig.hz
1513 bool "kexec system call"
1515 kexec is a system call that implements the ability to shutdown your
1516 current kernel, and to start another kernel. It is like a reboot
1517 but it is independent of the system firmware. And like a reboot
1518 you can start any kernel with it, not just Linux.
1520 The name comes from the similarity to the exec system call.
1522 It is an ongoing process to be certain the hardware in a machine
1523 is properly shutdown, so do not be surprised if this code does not
1524 initially work for you. It may help to enable device hotplugging
1525 support. As of this writing the exact hardware interface is
1526 strongly in flux, so no good recommendation can be made.
1529 bool "kernel crash dumps"
1530 depends on X86_64 || (X86_32 && HIGHMEM)
1532 Generate crash dump after being started by kexec.
1533 This should be normally only set in special crash dump kernels
1534 which are loaded in the main kernel with kexec-tools into
1535 a specially reserved region and then later executed after
1536 a crash by kdump/kexec. The crash dump kernel must be compiled
1537 to a memory address not used by the main kernel or BIOS using
1538 PHYSICAL_START, or it must be built as a relocatable image
1539 (CONFIG_RELOCATABLE=y).
1540 For more details see Documentation/kdump/kdump.txt
1543 bool "kexec jump (EXPERIMENTAL)"
1544 depends on EXPERIMENTAL
1545 depends on KEXEC && HIBERNATION
1547 Jump between original kernel and kexeced kernel and invoke
1548 code in physical address mode via KEXEC
1550 config PHYSICAL_START
1551 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1554 This gives the physical address where the kernel is loaded.
1556 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1557 bzImage will decompress itself to above physical address and
1558 run from there. Otherwise, bzImage will run from the address where
1559 it has been loaded by the boot loader and will ignore above physical
1562 In normal kdump cases one does not have to set/change this option
1563 as now bzImage can be compiled as a completely relocatable image
1564 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1565 address. This option is mainly useful for the folks who don't want
1566 to use a bzImage for capturing the crash dump and want to use a
1567 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1568 to be specifically compiled to run from a specific memory area
1569 (normally a reserved region) and this option comes handy.
1571 So if you are using bzImage for capturing the crash dump,
1572 leave the value here unchanged to 0x1000000 and set
1573 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1574 for capturing the crash dump change this value to start of
1575 the reserved region. In other words, it can be set based on
1576 the "X" value as specified in the "crashkernel=YM@XM"
1577 command line boot parameter passed to the panic-ed
1578 kernel. Please take a look at Documentation/kdump/kdump.txt
1579 for more details about crash dumps.
1581 Usage of bzImage for capturing the crash dump is recommended as
1582 one does not have to build two kernels. Same kernel can be used
1583 as production kernel and capture kernel. Above option should have
1584 gone away after relocatable bzImage support is introduced. But it
1585 is present because there are users out there who continue to use
1586 vmlinux for dump capture. This option should go away down the
1589 Don't change this unless you know what you are doing.
1592 bool "Build a relocatable kernel"
1595 This builds a kernel image that retains relocation information
1596 so it can be loaded someplace besides the default 1MB.
1597 The relocations tend to make the kernel binary about 10% larger,
1598 but are discarded at runtime.
1600 One use is for the kexec on panic case where the recovery kernel
1601 must live at a different physical address than the primary
1604 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1605 it has been loaded at and the compile time physical address
1606 (CONFIG_PHYSICAL_START) is ignored.
1608 # Relocation on x86-32 needs some additional build support
1609 config X86_NEED_RELOCS
1611 depends on X86_32 && RELOCATABLE
1613 config PHYSICAL_ALIGN
1614 hex "Alignment value to which kernel should be aligned" if X86_32
1616 range 0x2000 0x1000000
1618 This value puts the alignment restrictions on physical address
1619 where kernel is loaded and run from. Kernel is compiled for an
1620 address which meets above alignment restriction.
1622 If bootloader loads the kernel at a non-aligned address and
1623 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1624 address aligned to above value and run from there.
1626 If bootloader loads the kernel at a non-aligned address and
1627 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1628 load address and decompress itself to the address it has been
1629 compiled for and run from there. The address for which kernel is
1630 compiled already meets above alignment restrictions. Hence the
1631 end result is that kernel runs from a physical address meeting
1632 above alignment restrictions.
1634 Don't change this unless you know what you are doing.
1637 bool "Support for hot-pluggable CPUs"
1638 depends on SMP && HOTPLUG
1640 Say Y here to allow turning CPUs off and on. CPUs can be
1641 controlled through /sys/devices/system/cpu.
1642 ( Note: power management support will enable this option
1643 automatically on SMP systems. )
1644 Say N if you want to disable CPU hotplug.
1648 prompt "Compat VDSO support"
1649 depends on X86_32 || IA32_EMULATION
1651 Map the 32-bit VDSO to the predictable old-style address too.
1653 Say N here if you are running a sufficiently recent glibc
1654 version (2.3.3 or later), to remove the high-mapped
1655 VDSO mapping and to exclusively use the randomized VDSO.
1660 bool "Built-in kernel command line"
1662 Allow for specifying boot arguments to the kernel at
1663 build time. On some systems (e.g. embedded ones), it is
1664 necessary or convenient to provide some or all of the
1665 kernel boot arguments with the kernel itself (that is,
1666 to not rely on the boot loader to provide them.)
1668 To compile command line arguments into the kernel,
1669 set this option to 'Y', then fill in the
1670 the boot arguments in CONFIG_CMDLINE.
1672 Systems with fully functional boot loaders (i.e. non-embedded)
1673 should leave this option set to 'N'.
1676 string "Built-in kernel command string"
1677 depends on CMDLINE_BOOL
1680 Enter arguments here that should be compiled into the kernel
1681 image and used at boot time. If the boot loader provides a
1682 command line at boot time, it is appended to this string to
1683 form the full kernel command line, when the system boots.
1685 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1686 change this behavior.
1688 In most cases, the command line (whether built-in or provided
1689 by the boot loader) should specify the device for the root
1692 config CMDLINE_OVERRIDE
1693 bool "Built-in command line overrides boot loader arguments"
1694 depends on CMDLINE_BOOL
1696 Set this option to 'Y' to have the kernel ignore the boot loader
1697 command line, and use ONLY the built-in command line.
1699 This is used to work around broken boot loaders. This should
1700 be set to 'N' under normal conditions.
1704 config ARCH_ENABLE_MEMORY_HOTPLUG
1706 depends on X86_64 || (X86_32 && HIGHMEM)
1708 config ARCH_ENABLE_MEMORY_HOTREMOVE
1710 depends on MEMORY_HOTPLUG
1712 config HAVE_ARCH_EARLY_PFN_TO_NID
1716 config USE_PERCPU_NUMA_NODE_ID
1720 menu "Power management and ACPI options"
1722 config ARCH_HIBERNATION_HEADER
1724 depends on X86_64 && HIBERNATION
1726 source "kernel/power/Kconfig"
1728 source "drivers/acpi/Kconfig"
1730 source "drivers/sfi/Kconfig"
1734 depends on APM || APM_MODULE
1737 tristate "APM (Advanced Power Management) BIOS support"
1738 depends on X86_32 && PM_SLEEP
1740 APM is a BIOS specification for saving power using several different
1741 techniques. This is mostly useful for battery powered laptops with
1742 APM compliant BIOSes. If you say Y here, the system time will be
1743 reset after a RESUME operation, the /proc/apm device will provide
1744 battery status information, and user-space programs will receive
1745 notification of APM "events" (e.g. battery status change).
1747 If you select "Y" here, you can disable actual use of the APM
1748 BIOS by passing the "apm=off" option to the kernel at boot time.
1750 Note that the APM support is almost completely disabled for
1751 machines with more than one CPU.
1753 In order to use APM, you will need supporting software. For location
1754 and more information, read <file:Documentation/power/pm.txt> and the
1755 Battery Powered Linux mini-HOWTO, available from
1756 <http://www.tldp.org/docs.html#howto>.
1758 This driver does not spin down disk drives (see the hdparm(8)
1759 manpage ("man 8 hdparm") for that), and it doesn't turn off
1760 VESA-compliant "green" monitors.
1762 This driver does not support the TI 4000M TravelMate and the ACER
1763 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1764 desktop machines also don't have compliant BIOSes, and this driver
1765 may cause those machines to panic during the boot phase.
1767 Generally, if you don't have a battery in your machine, there isn't
1768 much point in using this driver and you should say N. If you get
1769 random kernel OOPSes or reboots that don't seem to be related to
1770 anything, try disabling/enabling this option (or disabling/enabling
1773 Some other things you should try when experiencing seemingly random,
1776 1) make sure that you have enough swap space and that it is
1778 2) pass the "no-hlt" option to the kernel
1779 3) switch on floating point emulation in the kernel and pass
1780 the "no387" option to the kernel
1781 4) pass the "floppy=nodma" option to the kernel
1782 5) pass the "mem=4M" option to the kernel (thereby disabling
1783 all but the first 4 MB of RAM)
1784 6) make sure that the CPU is not over clocked.
1785 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1786 8) disable the cache from your BIOS settings
1787 9) install a fan for the video card or exchange video RAM
1788 10) install a better fan for the CPU
1789 11) exchange RAM chips
1790 12) exchange the motherboard.
1792 To compile this driver as a module, choose M here: the
1793 module will be called apm.
1797 config APM_IGNORE_USER_SUSPEND
1798 bool "Ignore USER SUSPEND"
1800 This option will ignore USER SUSPEND requests. On machines with a
1801 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1802 series notebooks, it is necessary to say Y because of a BIOS bug.
1804 config APM_DO_ENABLE
1805 bool "Enable PM at boot time"
1807 Enable APM features at boot time. From page 36 of the APM BIOS
1808 specification: "When disabled, the APM BIOS does not automatically
1809 power manage devices, enter the Standby State, enter the Suspend
1810 State, or take power saving steps in response to CPU Idle calls."
1811 This driver will make CPU Idle calls when Linux is idle (unless this
1812 feature is turned off -- see "Do CPU IDLE calls", below). This
1813 should always save battery power, but more complicated APM features
1814 will be dependent on your BIOS implementation. You may need to turn
1815 this option off if your computer hangs at boot time when using APM
1816 support, or if it beeps continuously instead of suspending. Turn
1817 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1818 T400CDT. This is off by default since most machines do fine without
1822 bool "Make CPU Idle calls when idle"
1824 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1825 On some machines, this can activate improved power savings, such as
1826 a slowed CPU clock rate, when the machine is idle. These idle calls
1827 are made after the idle loop has run for some length of time (e.g.,
1828 333 mS). On some machines, this will cause a hang at boot time or
1829 whenever the CPU becomes idle. (On machines with more than one CPU,
1830 this option does nothing.)
1832 config APM_DISPLAY_BLANK
1833 bool "Enable console blanking using APM"
1835 Enable console blanking using the APM. Some laptops can use this to
1836 turn off the LCD backlight when the screen blanker of the Linux
1837 virtual console blanks the screen. Note that this is only used by
1838 the virtual console screen blanker, and won't turn off the backlight
1839 when using the X Window system. This also doesn't have anything to
1840 do with your VESA-compliant power-saving monitor. Further, this
1841 option doesn't work for all laptops -- it might not turn off your
1842 backlight at all, or it might print a lot of errors to the console,
1843 especially if you are using gpm.
1845 config APM_ALLOW_INTS
1846 bool "Allow interrupts during APM BIOS calls"
1848 Normally we disable external interrupts while we are making calls to
1849 the APM BIOS as a measure to lessen the effects of a badly behaving
1850 BIOS implementation. The BIOS should reenable interrupts if it
1851 needs to. Unfortunately, some BIOSes do not -- especially those in
1852 many of the newer IBM Thinkpads. If you experience hangs when you
1853 suspend, try setting this to Y. Otherwise, say N.
1857 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1859 source "drivers/cpuidle/Kconfig"
1861 source "drivers/idle/Kconfig"
1866 menu "Bus options (PCI etc.)"
1871 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1873 Find out whether you have a PCI motherboard. PCI is the name of a
1874 bus system, i.e. the way the CPU talks to the other stuff inside
1875 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1876 VESA. If you have PCI, say Y, otherwise N.
1879 prompt "PCI access mode"
1880 depends on X86_32 && PCI
1883 On PCI systems, the BIOS can be used to detect the PCI devices and
1884 determine their configuration. However, some old PCI motherboards
1885 have BIOS bugs and may crash if this is done. Also, some embedded
1886 PCI-based systems don't have any BIOS at all. Linux can also try to
1887 detect the PCI hardware directly without using the BIOS.
1889 With this option, you can specify how Linux should detect the
1890 PCI devices. If you choose "BIOS", the BIOS will be used,
1891 if you choose "Direct", the BIOS won't be used, and if you
1892 choose "MMConfig", then PCI Express MMCONFIG will be used.
1893 If you choose "Any", the kernel will try MMCONFIG, then the
1894 direct access method and falls back to the BIOS if that doesn't
1895 work. If unsure, go with the default, which is "Any".
1900 config PCI_GOMMCONFIG
1917 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1919 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1922 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1926 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1930 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1937 bool "Support mmconfig PCI config space access"
1938 depends on X86_64 && PCI && ACPI
1940 config PCI_CNB20LE_QUIRK
1941 bool "Read CNB20LE Host Bridge Windows"
1944 Read the PCI windows out of the CNB20LE host bridge. This allows
1945 PCI hotplug to work on systems with the CNB20LE chipset which do
1949 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1950 depends on PCI_MSI && ACPI && EXPERIMENTAL
1952 DMA remapping (DMAR) devices support enables independent address
1953 translations for Direct Memory Access (DMA) from devices.
1954 These DMA remapping devices are reported via ACPI tables
1955 and include PCI device scope covered by these DMA
1958 config DMAR_DEFAULT_ON
1960 prompt "Enable DMA Remapping Devices by default"
1963 Selecting this option will enable a DMAR device at boot time if
1964 one is found. If this option is not selected, DMAR support can
1965 be enabled by passing intel_iommu=on to the kernel. It is
1966 recommended you say N here while the DMAR code remains
1969 config DMAR_BROKEN_GFX_WA
1970 bool "Workaround broken graphics drivers (going away soon)"
1971 depends on DMAR && BROKEN
1973 Current Graphics drivers tend to use physical address
1974 for DMA and avoid using DMA APIs. Setting this config
1975 option permits the IOMMU driver to set a unity map for
1976 all the OS-visible memory. Hence the driver can continue
1977 to use physical addresses for DMA, at least until this
1978 option is removed in the 2.6.32 kernel.
1980 config DMAR_FLOPPY_WA
1984 Floppy disk drivers are known to bypass DMA API calls
1985 thereby failing to work when IOMMU is enabled. This
1986 workaround will setup a 1:1 mapping for the first
1987 16MiB to make floppy (an ISA device) work.
1990 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1991 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1993 Supports Interrupt remapping for IO-APIC and MSI devices.
1994 To use x2apic mode in the CPU's which support x2APIC enhancements or
1995 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1997 source "drivers/pci/pcie/Kconfig"
1999 source "drivers/pci/Kconfig"
2001 # x86_64 have no ISA slots, but do have ISA-style DMA.
2010 Find out whether you have ISA slots on your motherboard. ISA is the
2011 name of a bus system, i.e. the way the CPU talks to the other stuff
2012 inside your box. Other bus systems are PCI, EISA, MicroChannel
2013 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2014 newer boards don't support it. If you have ISA, say Y, otherwise N.
2020 The Extended Industry Standard Architecture (EISA) bus was
2021 developed as an open alternative to the IBM MicroChannel bus.
2023 The EISA bus provided some of the features of the IBM MicroChannel
2024 bus while maintaining backward compatibility with cards made for
2025 the older ISA bus. The EISA bus saw limited use between 1988 and
2026 1995 when it was made obsolete by the PCI bus.
2028 Say Y here if you are building a kernel for an EISA-based machine.
2032 source "drivers/eisa/Kconfig"
2037 MicroChannel Architecture is found in some IBM PS/2 machines and
2038 laptops. It is a bus system similar to PCI or ISA. See
2039 <file:Documentation/mca.txt> (and especially the web page given
2040 there) before attempting to build an MCA bus kernel.
2042 source "drivers/mca/Kconfig"
2045 tristate "NatSemi SCx200 support"
2047 This provides basic support for National Semiconductor's
2048 (now AMD's) Geode processors. The driver probes for the
2049 PCI-IDs of several on-chip devices, so its a good dependency
2050 for other scx200_* drivers.
2052 If compiled as a module, the driver is named scx200.
2054 config SCx200HR_TIMER
2055 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2059 This driver provides a clocksource built upon the on-chip
2060 27MHz high-resolution timer. Its also a workaround for
2061 NSC Geode SC-1100's buggy TSC, which loses time when the
2062 processor goes idle (as is done by the scheduler). The
2063 other workaround is idle=poll boot option.
2066 bool "One Laptop Per Child support"
2069 Add support for detecting the unique features of the OLPC
2072 config OLPC_OPENFIRMWARE
2073 bool "Support for OLPC's Open Firmware"
2074 depends on !X86_64 && !X86_PAE
2077 This option adds support for the implementation of Open Firmware
2078 that is used on the OLPC XO-1 Children's Machine.
2079 If unsure, say N here.
2085 depends on CPU_SUP_AMD && PCI
2087 source "drivers/pcmcia/Kconfig"
2089 source "drivers/pci/hotplug/Kconfig"
2094 menu "Executable file formats / Emulations"
2096 source "fs/Kconfig.binfmt"
2098 config IA32_EMULATION
2099 bool "IA32 Emulation"
2101 select COMPAT_BINFMT_ELF
2103 Include code to run 32-bit programs under a 64-bit kernel. You should
2104 likely turn this on, unless you're 100% sure that you don't have any
2105 32-bit programs left.
2108 tristate "IA32 a.out support"
2109 depends on IA32_EMULATION
2111 Support old a.out binaries in the 32bit emulation.
2115 depends on IA32_EMULATION
2117 config COMPAT_FOR_U64_ALIGNMENT
2121 config SYSVIPC_COMPAT
2123 depends on COMPAT && SYSVIPC
2128 config HAVE_ATOMIC_IOMAP
2132 config HAVE_TEXT_POKE_SMP
2134 select STOP_MACHINE if SMP
2136 source "net/Kconfig"
2138 source "drivers/Kconfig"
2140 source "drivers/firmware/Kconfig"
2144 source "arch/x86/Kconfig.debug"
2146 source "security/Kconfig"
2148 source "crypto/Kconfig"
2150 source "arch/x86/kvm/Kconfig"
2152 source "lib/Kconfig"