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 && AMD_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 config IRQ_TIME_ACCOUNTING
803 bool "Fine granularity task level IRQ time accounting"
806 Select this option to enable fine granularity task irq time
807 accounting. This is done by reading a timestamp on each
808 transitions between softirq and hardirq state, so there can be a
809 small performance impact.
811 If in doubt, say N here.
813 source "kernel/Kconfig.preempt"
816 bool "Local APIC support on uniprocessors"
817 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
819 A local APIC (Advanced Programmable Interrupt Controller) is an
820 integrated interrupt controller in the CPU. If you have a single-CPU
821 system which has a processor with a local APIC, you can say Y here to
822 enable and use it. If you say Y here even though your machine doesn't
823 have a local APIC, then the kernel will still run with no slowdown at
824 all. The local APIC supports CPU-generated self-interrupts (timer,
825 performance counters), and the NMI watchdog which detects hard
829 bool "IO-APIC support on uniprocessors"
830 depends on X86_UP_APIC
832 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
833 SMP-capable replacement for PC-style interrupt controllers. Most
834 SMP systems and many recent uniprocessor systems have one.
836 If you have a single-CPU system with an IO-APIC, you can say Y here
837 to use it. If you say Y here even though your machine doesn't have
838 an IO-APIC, then the kernel will still run with no slowdown at all.
840 config X86_LOCAL_APIC
842 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
846 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
848 config X86_VISWS_APIC
850 depends on X86_32 && X86_VISWS
852 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
853 bool "Reroute for broken boot IRQs"
854 depends on X86_IO_APIC
856 This option enables a workaround that fixes a source of
857 spurious interrupts. This is recommended when threaded
858 interrupt handling is used on systems where the generation of
859 superfluous "boot interrupts" cannot be disabled.
861 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
862 entry in the chipset's IO-APIC is masked (as, e.g. the RT
863 kernel does during interrupt handling). On chipsets where this
864 boot IRQ generation cannot be disabled, this workaround keeps
865 the original IRQ line masked so that only the equivalent "boot
866 IRQ" is delivered to the CPUs. The workaround also tells the
867 kernel to set up the IRQ handler on the boot IRQ line. In this
868 way only one interrupt is delivered to the kernel. Otherwise
869 the spurious second interrupt may cause the kernel to bring
870 down (vital) interrupt lines.
872 Only affects "broken" chipsets. Interrupt sharing may be
873 increased on these systems.
876 bool "Machine Check / overheating reporting"
878 Machine Check support allows the processor to notify the
879 kernel if it detects a problem (e.g. overheating, data corruption).
880 The action the kernel takes depends on the severity of the problem,
881 ranging from warning messages to halting the machine.
885 prompt "Intel MCE features"
886 depends on X86_MCE && X86_LOCAL_APIC
888 Additional support for intel specific MCE features such as
893 prompt "AMD MCE features"
894 depends on X86_MCE && X86_LOCAL_APIC
896 Additional support for AMD specific MCE features such as
897 the DRAM Error Threshold.
899 config X86_ANCIENT_MCE
900 bool "Support for old Pentium 5 / WinChip machine checks"
901 depends on X86_32 && X86_MCE
903 Include support for machine check handling on old Pentium 5 or WinChip
904 systems. These typically need to be enabled explicitely on the command
907 config X86_MCE_THRESHOLD
908 depends on X86_MCE_AMD || X86_MCE_INTEL
911 config X86_MCE_INJECT
913 tristate "Machine check injector support"
915 Provide support for injecting machine checks for testing purposes.
916 If you don't know what a machine check is and you don't do kernel
917 QA it is safe to say n.
919 config X86_THERMAL_VECTOR
921 depends on X86_MCE_INTEL
924 bool "Enable VM86 support" if EMBEDDED
928 This option is required by programs like DOSEMU to run 16-bit legacy
929 code on X86 processors. It also may be needed by software like
930 XFree86 to initialize some video cards via BIOS. Disabling this
931 option saves about 6k.
934 tristate "Toshiba Laptop support"
937 This adds a driver to safely access the System Management Mode of
938 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
939 not work on models with a Phoenix BIOS. The System Management Mode
940 is used to set the BIOS and power saving options on Toshiba portables.
942 For information on utilities to make use of this driver see the
943 Toshiba Linux utilities web site at:
944 <http://www.buzzard.org.uk/toshiba/>.
946 Say Y if you intend to run this kernel on a Toshiba portable.
950 tristate "Dell laptop support"
952 This adds a driver to safely access the System Management Mode
953 of the CPU on the Dell Inspiron 8000. The System Management Mode
954 is used to read cpu temperature and cooling fan status and to
955 control the fans on the I8K portables.
957 This driver has been tested only on the Inspiron 8000 but it may
958 also work with other Dell laptops. You can force loading on other
959 models by passing the parameter `force=1' to the module. Use at
962 For information on utilities to make use of this driver see the
963 I8K Linux utilities web site at:
964 <http://people.debian.org/~dz/i8k/>
966 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
969 config X86_REBOOTFIXUPS
970 bool "Enable X86 board specific fixups for reboot"
973 This enables chipset and/or board specific fixups to be done
974 in order to get reboot to work correctly. This is only needed on
975 some combinations of hardware and BIOS. The symptom, for which
976 this config is intended, is when reboot ends with a stalled/hung
979 Currently, the only fixup is for the Geode machines using
980 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
982 Say Y if you want to enable the fixup. Currently, it's safe to
983 enable this option even if you don't need it.
987 tristate "/dev/cpu/microcode - microcode support"
990 If you say Y here, you will be able to update the microcode on
991 certain Intel and AMD processors. The Intel support is for the
992 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
993 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
994 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
995 You will obviously need the actual microcode binary data itself
996 which is not shipped with the Linux kernel.
998 This option selects the general module only, you need to select
999 at least one vendor specific module as well.
1001 To compile this driver as a module, choose M here: the
1002 module will be called microcode.
1004 config MICROCODE_INTEL
1005 bool "Intel microcode patch loading support"
1006 depends on MICROCODE
1010 This options enables microcode patch loading support for Intel
1013 For latest news and information on obtaining all the required
1014 Intel ingredients for this driver, check:
1015 <http://www.urbanmyth.org/microcode/>.
1017 config MICROCODE_AMD
1018 bool "AMD microcode patch loading support"
1019 depends on MICROCODE
1022 If you select this option, microcode patch loading support for AMD
1023 processors will be enabled.
1025 config MICROCODE_OLD_INTERFACE
1027 depends on MICROCODE
1030 tristate "/dev/cpu/*/msr - Model-specific register support"
1032 This device gives privileged processes access to the x86
1033 Model-Specific Registers (MSRs). It is a character device with
1034 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1035 MSR accesses are directed to a specific CPU on multi-processor
1039 tristate "/dev/cpu/*/cpuid - CPU information support"
1041 This device gives processes access to the x86 CPUID instruction to
1042 be executed on a specific processor. It is a character device
1043 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1047 prompt "High Memory Support"
1048 default HIGHMEM64G if X86_NUMAQ
1054 depends on !X86_NUMAQ
1056 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1057 However, the address space of 32-bit x86 processors is only 4
1058 Gigabytes large. That means that, if you have a large amount of
1059 physical memory, not all of it can be "permanently mapped" by the
1060 kernel. The physical memory that's not permanently mapped is called
1063 If you are compiling a kernel which will never run on a machine with
1064 more than 1 Gigabyte total physical RAM, answer "off" here (default
1065 choice and suitable for most users). This will result in a "3GB/1GB"
1066 split: 3GB are mapped so that each process sees a 3GB virtual memory
1067 space and the remaining part of the 4GB virtual memory space is used
1068 by the kernel to permanently map as much physical memory as
1071 If the machine has between 1 and 4 Gigabytes physical RAM, then
1074 If more than 4 Gigabytes is used then answer "64GB" here. This
1075 selection turns Intel PAE (Physical Address Extension) mode on.
1076 PAE implements 3-level paging on IA32 processors. PAE is fully
1077 supported by Linux, PAE mode is implemented on all recent Intel
1078 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1079 then the kernel will not boot on CPUs that don't support PAE!
1081 The actual amount of total physical memory will either be
1082 auto detected or can be forced by using a kernel command line option
1083 such as "mem=256M". (Try "man bootparam" or see the documentation of
1084 your boot loader (lilo or loadlin) about how to pass options to the
1085 kernel at boot time.)
1087 If unsure, say "off".
1091 depends on !X86_NUMAQ
1093 Select this if you have a 32-bit processor and between 1 and 4
1094 gigabytes of physical RAM.
1098 depends on !M386 && !M486
1101 Select this if you have a 32-bit processor and more than 4
1102 gigabytes of physical RAM.
1107 depends on EXPERIMENTAL
1108 prompt "Memory split" if EMBEDDED
1112 Select the desired split between kernel and user memory.
1114 If the address range available to the kernel is less than the
1115 physical memory installed, the remaining memory will be available
1116 as "high memory". Accessing high memory is a little more costly
1117 than low memory, as it needs to be mapped into the kernel first.
1118 Note that increasing the kernel address space limits the range
1119 available to user programs, making the address space there
1120 tighter. Selecting anything other than the default 3G/1G split
1121 will also likely make your kernel incompatible with binary-only
1124 If you are not absolutely sure what you are doing, leave this
1128 bool "3G/1G user/kernel split"
1129 config VMSPLIT_3G_OPT
1131 bool "3G/1G user/kernel split (for full 1G low memory)"
1133 bool "2G/2G user/kernel split"
1134 config VMSPLIT_2G_OPT
1136 bool "2G/2G user/kernel split (for full 2G low memory)"
1138 bool "1G/3G user/kernel split"
1143 default 0xB0000000 if VMSPLIT_3G_OPT
1144 default 0x80000000 if VMSPLIT_2G
1145 default 0x78000000 if VMSPLIT_2G_OPT
1146 default 0x40000000 if VMSPLIT_1G
1152 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1155 bool "PAE (Physical Address Extension) Support"
1156 depends on X86_32 && !HIGHMEM4G
1158 PAE is required for NX support, and furthermore enables
1159 larger swapspace support for non-overcommit purposes. It
1160 has the cost of more pagetable lookup overhead, and also
1161 consumes more pagetable space per process.
1163 config ARCH_PHYS_ADDR_T_64BIT
1164 def_bool X86_64 || X86_PAE
1166 config ARCH_DMA_ADDR_T_64BIT
1167 def_bool X86_64 || HIGHMEM64G
1169 config DIRECT_GBPAGES
1170 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1174 Allow the kernel linear mapping to use 1GB pages on CPUs that
1175 support it. This can improve the kernel's performance a tiny bit by
1176 reducing TLB pressure. If in doubt, say "Y".
1178 # Common NUMA Features
1180 bool "Numa Memory Allocation and Scheduler Support"
1182 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1183 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1185 Enable NUMA (Non Uniform Memory Access) support.
1187 The kernel will try to allocate memory used by a CPU on the
1188 local memory controller of the CPU and add some more
1189 NUMA awareness to the kernel.
1191 For 64-bit this is recommended if the system is Intel Core i7
1192 (or later), AMD Opteron, or EM64T NUMA.
1194 For 32-bit this is only needed on (rare) 32-bit-only platforms
1195 that support NUMA topologies, such as NUMAQ / Summit, or if you
1196 boot a 32-bit kernel on a 64-bit NUMA platform.
1198 Otherwise, you should say N.
1200 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1201 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1205 prompt "Old style AMD Opteron NUMA detection"
1206 depends on X86_64 && NUMA && PCI
1208 Enable K8 NUMA node topology detection. You should say Y here if
1209 you have a multi processor AMD K8 system. This uses an old
1210 method to read the NUMA configuration directly from the builtin
1211 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1212 instead, which also takes priority if both are compiled in.
1214 config X86_64_ACPI_NUMA
1216 prompt "ACPI NUMA detection"
1217 depends on X86_64 && NUMA && ACPI && PCI
1220 Enable ACPI SRAT based node topology detection.
1222 # Some NUMA nodes have memory ranges that span
1223 # other nodes. Even though a pfn is valid and
1224 # between a node's start and end pfns, it may not
1225 # reside on that node. See memmap_init_zone()
1227 config NODES_SPAN_OTHER_NODES
1229 depends on X86_64_ACPI_NUMA
1232 bool "NUMA emulation"
1233 depends on X86_64 && NUMA
1235 Enable NUMA emulation. A flat machine will be split
1236 into virtual nodes when booted with "numa=fake=N", where N is the
1237 number of nodes. This is only useful for debugging.
1240 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1242 default "10" if MAXSMP
1243 default "6" if X86_64
1244 default "4" if X86_NUMAQ
1246 depends on NEED_MULTIPLE_NODES
1248 Specify the maximum number of NUMA Nodes available on the target
1249 system. Increases memory reserved to accommodate various tables.
1251 config HAVE_ARCH_BOOTMEM
1253 depends on X86_32 && NUMA
1255 config ARCH_HAVE_MEMORY_PRESENT
1257 depends on X86_32 && DISCONTIGMEM
1259 config NEED_NODE_MEMMAP_SIZE
1261 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1263 config HAVE_ARCH_ALLOC_REMAP
1265 depends on X86_32 && NUMA
1267 config ARCH_FLATMEM_ENABLE
1269 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1271 config ARCH_DISCONTIGMEM_ENABLE
1273 depends on NUMA && X86_32
1275 config ARCH_DISCONTIGMEM_DEFAULT
1277 depends on NUMA && X86_32
1279 config ARCH_PROC_KCORE_TEXT
1281 depends on X86_64 && PROC_KCORE
1283 config ARCH_SPARSEMEM_DEFAULT
1287 config ARCH_SPARSEMEM_ENABLE
1289 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1290 select SPARSEMEM_STATIC if X86_32
1291 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1293 config ARCH_SELECT_MEMORY_MODEL
1295 depends on ARCH_SPARSEMEM_ENABLE
1297 config ARCH_MEMORY_PROBE
1299 depends on MEMORY_HOTPLUG
1301 config ILLEGAL_POINTER_VALUE
1304 default 0xdead000000000000 if X86_64
1309 bool "Allocate 3rd-level pagetables from highmem"
1312 The VM uses one page table entry for each page of physical memory.
1313 For systems with a lot of RAM, this can be wasteful of precious
1314 low memory. Setting this option will put user-space page table
1315 entries in high memory.
1317 config X86_CHECK_BIOS_CORRUPTION
1318 bool "Check for low memory corruption"
1320 Periodically check for memory corruption in low memory, which
1321 is suspected to be caused by BIOS. Even when enabled in the
1322 configuration, it is disabled at runtime. Enable it by
1323 setting "memory_corruption_check=1" on the kernel command
1324 line. By default it scans the low 64k of memory every 60
1325 seconds; see the memory_corruption_check_size and
1326 memory_corruption_check_period parameters in
1327 Documentation/kernel-parameters.txt to adjust this.
1329 When enabled with the default parameters, this option has
1330 almost no overhead, as it reserves a relatively small amount
1331 of memory and scans it infrequently. It both detects corruption
1332 and prevents it from affecting the running system.
1334 It is, however, intended as a diagnostic tool; if repeatable
1335 BIOS-originated corruption always affects the same memory,
1336 you can use memmap= to prevent the kernel from using that
1339 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1340 bool "Set the default setting of memory_corruption_check"
1341 depends on X86_CHECK_BIOS_CORRUPTION
1344 Set whether the default state of memory_corruption_check is
1347 config X86_RESERVE_LOW
1348 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1352 Specify the amount of low memory to reserve for the BIOS.
1354 The first page contains BIOS data structures that the kernel
1355 must not use, so that page must always be reserved.
1357 By default we reserve the first 64K of physical RAM, as a
1358 number of BIOSes are known to corrupt that memory range
1359 during events such as suspend/resume or monitor cable
1360 insertion, so it must not be used by the kernel.
1362 You can set this to 4 if you are absolutely sure that you
1363 trust the BIOS to get all its memory reservations and usages
1364 right. If you know your BIOS have problems beyond the
1365 default 64K area, you can set this to 640 to avoid using the
1366 entire low memory range.
1368 If you have doubts about the BIOS (e.g. suspend/resume does
1369 not work or there's kernel crashes after certain hardware
1370 hotplug events) then you might want to enable
1371 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1372 typical corruption patterns.
1374 Leave this to the default value of 64 if you are unsure.
1376 config MATH_EMULATION
1378 prompt "Math emulation" if X86_32
1380 Linux can emulate a math coprocessor (used for floating point
1381 operations) if you don't have one. 486DX and Pentium processors have
1382 a math coprocessor built in, 486SX and 386 do not, unless you added
1383 a 487DX or 387, respectively. (The messages during boot time can
1384 give you some hints here ["man dmesg"].) Everyone needs either a
1385 coprocessor or this emulation.
1387 If you don't have a math coprocessor, you need to say Y here; if you
1388 say Y here even though you have a coprocessor, the coprocessor will
1389 be used nevertheless. (This behavior can be changed with the kernel
1390 command line option "no387", which comes handy if your coprocessor
1391 is broken. Try "man bootparam" or see the documentation of your boot
1392 loader (lilo or loadlin) about how to pass options to the kernel at
1393 boot time.) This means that it is a good idea to say Y here if you
1394 intend to use this kernel on different machines.
1396 More information about the internals of the Linux math coprocessor
1397 emulation can be found in <file:arch/x86/math-emu/README>.
1399 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1400 kernel, it won't hurt.
1404 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1406 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1407 the Memory Type Range Registers (MTRRs) may be used to control
1408 processor access to memory ranges. This is most useful if you have
1409 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1410 allows bus write transfers to be combined into a larger transfer
1411 before bursting over the PCI/AGP bus. This can increase performance
1412 of image write operations 2.5 times or more. Saying Y here creates a
1413 /proc/mtrr file which may be used to manipulate your processor's
1414 MTRRs. Typically the X server should use this.
1416 This code has a reasonably generic interface so that similar
1417 control registers on other processors can be easily supported
1420 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1421 Registers (ARRs) which provide a similar functionality to MTRRs. For
1422 these, the ARRs are used to emulate the MTRRs.
1423 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1424 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1425 write-combining. All of these processors are supported by this code
1426 and it makes sense to say Y here if you have one of them.
1428 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1429 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1430 can lead to all sorts of problems, so it's good to say Y here.
1432 You can safely say Y even if your machine doesn't have MTRRs, you'll
1433 just add about 9 KB to your kernel.
1435 See <file:Documentation/x86/mtrr.txt> for more information.
1437 config MTRR_SANITIZER
1439 prompt "MTRR cleanup support"
1442 Convert MTRR layout from continuous to discrete, so X drivers can
1443 add writeback entries.
1445 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1446 The largest mtrr entry size for a continuous block can be set with
1451 config MTRR_SANITIZER_ENABLE_DEFAULT
1452 int "MTRR cleanup enable value (0-1)"
1455 depends on MTRR_SANITIZER
1457 Enable mtrr cleanup default value
1459 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1460 int "MTRR cleanup spare reg num (0-7)"
1463 depends on MTRR_SANITIZER
1465 mtrr cleanup spare entries default, it can be changed via
1466 mtrr_spare_reg_nr=N on the kernel command line.
1470 prompt "x86 PAT support" if EMBEDDED
1473 Use PAT attributes to setup page level cache control.
1475 PATs are the modern equivalents of MTRRs and are much more
1476 flexible than MTRRs.
1478 Say N here if you see bootup problems (boot crash, boot hang,
1479 spontaneous reboots) or a non-working video driver.
1483 config ARCH_USES_PG_UNCACHED
1488 bool "EFI runtime service support"
1491 This enables the kernel to use EFI runtime services that are
1492 available (such as the EFI variable services).
1494 This option is only useful on systems that have EFI firmware.
1495 In addition, you should use the latest ELILO loader available
1496 at <http://elilo.sourceforge.net> in order to take advantage
1497 of EFI runtime services. However, even with this option, the
1498 resultant kernel should continue to boot on existing non-EFI
1503 prompt "Enable seccomp to safely compute untrusted bytecode"
1505 This kernel feature is useful for number crunching applications
1506 that may need to compute untrusted bytecode during their
1507 execution. By using pipes or other transports made available to
1508 the process as file descriptors supporting the read/write
1509 syscalls, it's possible to isolate those applications in
1510 their own address space using seccomp. Once seccomp is
1511 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1512 and the task is only allowed to execute a few safe syscalls
1513 defined by each seccomp mode.
1515 If unsure, say Y. Only embedded should say N here.
1517 config CC_STACKPROTECTOR
1518 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1520 This option turns on the -fstack-protector GCC feature. This
1521 feature puts, at the beginning of functions, a canary value on
1522 the stack just before the return address, and validates
1523 the value just before actually returning. Stack based buffer
1524 overflows (that need to overwrite this return address) now also
1525 overwrite the canary, which gets detected and the attack is then
1526 neutralized via a kernel panic.
1528 This feature requires gcc version 4.2 or above, or a distribution
1529 gcc with the feature backported. Older versions are automatically
1530 detected and for those versions, this configuration option is
1531 ignored. (and a warning is printed during bootup)
1533 source kernel/Kconfig.hz
1536 bool "kexec system call"
1538 kexec is a system call that implements the ability to shutdown your
1539 current kernel, and to start another kernel. It is like a reboot
1540 but it is independent of the system firmware. And like a reboot
1541 you can start any kernel with it, not just Linux.
1543 The name comes from the similarity to the exec system call.
1545 It is an ongoing process to be certain the hardware in a machine
1546 is properly shutdown, so do not be surprised if this code does not
1547 initially work for you. It may help to enable device hotplugging
1548 support. As of this writing the exact hardware interface is
1549 strongly in flux, so no good recommendation can be made.
1552 bool "kernel crash dumps"
1553 depends on X86_64 || (X86_32 && HIGHMEM)
1555 Generate crash dump after being started by kexec.
1556 This should be normally only set in special crash dump kernels
1557 which are loaded in the main kernel with kexec-tools into
1558 a specially reserved region and then later executed after
1559 a crash by kdump/kexec. The crash dump kernel must be compiled
1560 to a memory address not used by the main kernel or BIOS using
1561 PHYSICAL_START, or it must be built as a relocatable image
1562 (CONFIG_RELOCATABLE=y).
1563 For more details see Documentation/kdump/kdump.txt
1566 bool "kexec jump (EXPERIMENTAL)"
1567 depends on EXPERIMENTAL
1568 depends on KEXEC && HIBERNATION
1570 Jump between original kernel and kexeced kernel and invoke
1571 code in physical address mode via KEXEC
1573 config PHYSICAL_START
1574 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1577 This gives the physical address where the kernel is loaded.
1579 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1580 bzImage will decompress itself to above physical address and
1581 run from there. Otherwise, bzImage will run from the address where
1582 it has been loaded by the boot loader and will ignore above physical
1585 In normal kdump cases one does not have to set/change this option
1586 as now bzImage can be compiled as a completely relocatable image
1587 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1588 address. This option is mainly useful for the folks who don't want
1589 to use a bzImage for capturing the crash dump and want to use a
1590 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1591 to be specifically compiled to run from a specific memory area
1592 (normally a reserved region) and this option comes handy.
1594 So if you are using bzImage for capturing the crash dump,
1595 leave the value here unchanged to 0x1000000 and set
1596 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1597 for capturing the crash dump change this value to start of
1598 the reserved region. In other words, it can be set based on
1599 the "X" value as specified in the "crashkernel=YM@XM"
1600 command line boot parameter passed to the panic-ed
1601 kernel. Please take a look at Documentation/kdump/kdump.txt
1602 for more details about crash dumps.
1604 Usage of bzImage for capturing the crash dump is recommended as
1605 one does not have to build two kernels. Same kernel can be used
1606 as production kernel and capture kernel. Above option should have
1607 gone away after relocatable bzImage support is introduced. But it
1608 is present because there are users out there who continue to use
1609 vmlinux for dump capture. This option should go away down the
1612 Don't change this unless you know what you are doing.
1615 bool "Build a relocatable kernel"
1618 This builds a kernel image that retains relocation information
1619 so it can be loaded someplace besides the default 1MB.
1620 The relocations tend to make the kernel binary about 10% larger,
1621 but are discarded at runtime.
1623 One use is for the kexec on panic case where the recovery kernel
1624 must live at a different physical address than the primary
1627 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1628 it has been loaded at and the compile time physical address
1629 (CONFIG_PHYSICAL_START) is ignored.
1631 # Relocation on x86-32 needs some additional build support
1632 config X86_NEED_RELOCS
1634 depends on X86_32 && RELOCATABLE
1636 config PHYSICAL_ALIGN
1637 hex "Alignment value to which kernel should be aligned" if X86_32
1639 range 0x2000 0x1000000
1641 This value puts the alignment restrictions on physical address
1642 where kernel is loaded and run from. Kernel is compiled for an
1643 address which meets above alignment restriction.
1645 If bootloader loads the kernel at a non-aligned address and
1646 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1647 address aligned to above value and run from there.
1649 If bootloader loads the kernel at a non-aligned address and
1650 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1651 load address and decompress itself to the address it has been
1652 compiled for and run from there. The address for which kernel is
1653 compiled already meets above alignment restrictions. Hence the
1654 end result is that kernel runs from a physical address meeting
1655 above alignment restrictions.
1657 Don't change this unless you know what you are doing.
1660 bool "Support for hot-pluggable CPUs"
1661 depends on SMP && HOTPLUG
1663 Say Y here to allow turning CPUs off and on. CPUs can be
1664 controlled through /sys/devices/system/cpu.
1665 ( Note: power management support will enable this option
1666 automatically on SMP systems. )
1667 Say N if you want to disable CPU hotplug.
1671 prompt "Compat VDSO support"
1672 depends on X86_32 || IA32_EMULATION
1674 Map the 32-bit VDSO to the predictable old-style address too.
1676 Say N here if you are running a sufficiently recent glibc
1677 version (2.3.3 or later), to remove the high-mapped
1678 VDSO mapping and to exclusively use the randomized VDSO.
1683 bool "Built-in kernel command line"
1685 Allow for specifying boot arguments to the kernel at
1686 build time. On some systems (e.g. embedded ones), it is
1687 necessary or convenient to provide some or all of the
1688 kernel boot arguments with the kernel itself (that is,
1689 to not rely on the boot loader to provide them.)
1691 To compile command line arguments into the kernel,
1692 set this option to 'Y', then fill in the
1693 the boot arguments in CONFIG_CMDLINE.
1695 Systems with fully functional boot loaders (i.e. non-embedded)
1696 should leave this option set to 'N'.
1699 string "Built-in kernel command string"
1700 depends on CMDLINE_BOOL
1703 Enter arguments here that should be compiled into the kernel
1704 image and used at boot time. If the boot loader provides a
1705 command line at boot time, it is appended to this string to
1706 form the full kernel command line, when the system boots.
1708 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1709 change this behavior.
1711 In most cases, the command line (whether built-in or provided
1712 by the boot loader) should specify the device for the root
1715 config CMDLINE_OVERRIDE
1716 bool "Built-in command line overrides boot loader arguments"
1717 depends on CMDLINE_BOOL
1719 Set this option to 'Y' to have the kernel ignore the boot loader
1720 command line, and use ONLY the built-in command line.
1722 This is used to work around broken boot loaders. This should
1723 be set to 'N' under normal conditions.
1727 config ARCH_ENABLE_MEMORY_HOTPLUG
1729 depends on X86_64 || (X86_32 && HIGHMEM)
1731 config ARCH_ENABLE_MEMORY_HOTREMOVE
1733 depends on MEMORY_HOTPLUG
1735 config HAVE_ARCH_EARLY_PFN_TO_NID
1739 config USE_PERCPU_NUMA_NODE_ID
1743 menu "Power management and ACPI options"
1745 config ARCH_HIBERNATION_HEADER
1747 depends on X86_64 && HIBERNATION
1749 source "kernel/power/Kconfig"
1751 source "drivers/acpi/Kconfig"
1753 source "drivers/sfi/Kconfig"
1757 depends on APM || APM_MODULE
1760 tristate "APM (Advanced Power Management) BIOS support"
1761 depends on X86_32 && PM_SLEEP
1763 APM is a BIOS specification for saving power using several different
1764 techniques. This is mostly useful for battery powered laptops with
1765 APM compliant BIOSes. If you say Y here, the system time will be
1766 reset after a RESUME operation, the /proc/apm device will provide
1767 battery status information, and user-space programs will receive
1768 notification of APM "events" (e.g. battery status change).
1770 If you select "Y" here, you can disable actual use of the APM
1771 BIOS by passing the "apm=off" option to the kernel at boot time.
1773 Note that the APM support is almost completely disabled for
1774 machines with more than one CPU.
1776 In order to use APM, you will need supporting software. For location
1777 and more information, read <file:Documentation/power/pm.txt> and the
1778 Battery Powered Linux mini-HOWTO, available from
1779 <http://www.tldp.org/docs.html#howto>.
1781 This driver does not spin down disk drives (see the hdparm(8)
1782 manpage ("man 8 hdparm") for that), and it doesn't turn off
1783 VESA-compliant "green" monitors.
1785 This driver does not support the TI 4000M TravelMate and the ACER
1786 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1787 desktop machines also don't have compliant BIOSes, and this driver
1788 may cause those machines to panic during the boot phase.
1790 Generally, if you don't have a battery in your machine, there isn't
1791 much point in using this driver and you should say N. If you get
1792 random kernel OOPSes or reboots that don't seem to be related to
1793 anything, try disabling/enabling this option (or disabling/enabling
1796 Some other things you should try when experiencing seemingly random,
1799 1) make sure that you have enough swap space and that it is
1801 2) pass the "no-hlt" option to the kernel
1802 3) switch on floating point emulation in the kernel and pass
1803 the "no387" option to the kernel
1804 4) pass the "floppy=nodma" option to the kernel
1805 5) pass the "mem=4M" option to the kernel (thereby disabling
1806 all but the first 4 MB of RAM)
1807 6) make sure that the CPU is not over clocked.
1808 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1809 8) disable the cache from your BIOS settings
1810 9) install a fan for the video card or exchange video RAM
1811 10) install a better fan for the CPU
1812 11) exchange RAM chips
1813 12) exchange the motherboard.
1815 To compile this driver as a module, choose M here: the
1816 module will be called apm.
1820 config APM_IGNORE_USER_SUSPEND
1821 bool "Ignore USER SUSPEND"
1823 This option will ignore USER SUSPEND requests. On machines with a
1824 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1825 series notebooks, it is necessary to say Y because of a BIOS bug.
1827 config APM_DO_ENABLE
1828 bool "Enable PM at boot time"
1830 Enable APM features at boot time. From page 36 of the APM BIOS
1831 specification: "When disabled, the APM BIOS does not automatically
1832 power manage devices, enter the Standby State, enter the Suspend
1833 State, or take power saving steps in response to CPU Idle calls."
1834 This driver will make CPU Idle calls when Linux is idle (unless this
1835 feature is turned off -- see "Do CPU IDLE calls", below). This
1836 should always save battery power, but more complicated APM features
1837 will be dependent on your BIOS implementation. You may need to turn
1838 this option off if your computer hangs at boot time when using APM
1839 support, or if it beeps continuously instead of suspending. Turn
1840 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1841 T400CDT. This is off by default since most machines do fine without
1845 bool "Make CPU Idle calls when idle"
1847 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1848 On some machines, this can activate improved power savings, such as
1849 a slowed CPU clock rate, when the machine is idle. These idle calls
1850 are made after the idle loop has run for some length of time (e.g.,
1851 333 mS). On some machines, this will cause a hang at boot time or
1852 whenever the CPU becomes idle. (On machines with more than one CPU,
1853 this option does nothing.)
1855 config APM_DISPLAY_BLANK
1856 bool "Enable console blanking using APM"
1858 Enable console blanking using the APM. Some laptops can use this to
1859 turn off the LCD backlight when the screen blanker of the Linux
1860 virtual console blanks the screen. Note that this is only used by
1861 the virtual console screen blanker, and won't turn off the backlight
1862 when using the X Window system. This also doesn't have anything to
1863 do with your VESA-compliant power-saving monitor. Further, this
1864 option doesn't work for all laptops -- it might not turn off your
1865 backlight at all, or it might print a lot of errors to the console,
1866 especially if you are using gpm.
1868 config APM_ALLOW_INTS
1869 bool "Allow interrupts during APM BIOS calls"
1871 Normally we disable external interrupts while we are making calls to
1872 the APM BIOS as a measure to lessen the effects of a badly behaving
1873 BIOS implementation. The BIOS should reenable interrupts if it
1874 needs to. Unfortunately, some BIOSes do not -- especially those in
1875 many of the newer IBM Thinkpads. If you experience hangs when you
1876 suspend, try setting this to Y. Otherwise, say N.
1880 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1882 source "drivers/cpuidle/Kconfig"
1884 source "drivers/idle/Kconfig"
1889 menu "Bus options (PCI etc.)"
1894 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1896 Find out whether you have a PCI motherboard. PCI is the name of a
1897 bus system, i.e. the way the CPU talks to the other stuff inside
1898 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1899 VESA. If you have PCI, say Y, otherwise N.
1902 prompt "PCI access mode"
1903 depends on X86_32 && PCI
1906 On PCI systems, the BIOS can be used to detect the PCI devices and
1907 determine their configuration. However, some old PCI motherboards
1908 have BIOS bugs and may crash if this is done. Also, some embedded
1909 PCI-based systems don't have any BIOS at all. Linux can also try to
1910 detect the PCI hardware directly without using the BIOS.
1912 With this option, you can specify how Linux should detect the
1913 PCI devices. If you choose "BIOS", the BIOS will be used,
1914 if you choose "Direct", the BIOS won't be used, and if you
1915 choose "MMConfig", then PCI Express MMCONFIG will be used.
1916 If you choose "Any", the kernel will try MMCONFIG, then the
1917 direct access method and falls back to the BIOS if that doesn't
1918 work. If unsure, go with the default, which is "Any".
1923 config PCI_GOMMCONFIG
1940 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1942 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1945 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1949 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1953 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1960 bool "Support mmconfig PCI config space access"
1961 depends on X86_64 && PCI && ACPI
1963 config PCI_CNB20LE_QUIRK
1964 bool "Read CNB20LE Host Bridge Windows"
1967 Read the PCI windows out of the CNB20LE host bridge. This allows
1968 PCI hotplug to work on systems with the CNB20LE chipset which do
1972 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1973 depends on PCI_MSI && ACPI && EXPERIMENTAL
1975 DMA remapping (DMAR) devices support enables independent address
1976 translations for Direct Memory Access (DMA) from devices.
1977 These DMA remapping devices are reported via ACPI tables
1978 and include PCI device scope covered by these DMA
1981 config DMAR_DEFAULT_ON
1983 prompt "Enable DMA Remapping Devices by default"
1986 Selecting this option will enable a DMAR device at boot time if
1987 one is found. If this option is not selected, DMAR support can
1988 be enabled by passing intel_iommu=on to the kernel. It is
1989 recommended you say N here while the DMAR code remains
1992 config DMAR_BROKEN_GFX_WA
1993 bool "Workaround broken graphics drivers (going away soon)"
1994 depends on DMAR && BROKEN
1996 Current Graphics drivers tend to use physical address
1997 for DMA and avoid using DMA APIs. Setting this config
1998 option permits the IOMMU driver to set a unity map for
1999 all the OS-visible memory. Hence the driver can continue
2000 to use physical addresses for DMA, at least until this
2001 option is removed in the 2.6.32 kernel.
2003 config DMAR_FLOPPY_WA
2007 Floppy disk drivers are known to bypass DMA API calls
2008 thereby failing to work when IOMMU is enabled. This
2009 workaround will setup a 1:1 mapping for the first
2010 16MiB to make floppy (an ISA device) work.
2013 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
2014 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
2016 Supports Interrupt remapping for IO-APIC and MSI devices.
2017 To use x2apic mode in the CPU's which support x2APIC enhancements or
2018 to support platforms with CPU's having > 8 bit APIC ID, say Y.
2020 source "drivers/pci/pcie/Kconfig"
2022 source "drivers/pci/Kconfig"
2024 # x86_64 have no ISA slots, but do have ISA-style DMA.
2033 Find out whether you have ISA slots on your motherboard. ISA is the
2034 name of a bus system, i.e. the way the CPU talks to the other stuff
2035 inside your box. Other bus systems are PCI, EISA, MicroChannel
2036 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2037 newer boards don't support it. If you have ISA, say Y, otherwise N.
2043 The Extended Industry Standard Architecture (EISA) bus was
2044 developed as an open alternative to the IBM MicroChannel bus.
2046 The EISA bus provided some of the features of the IBM MicroChannel
2047 bus while maintaining backward compatibility with cards made for
2048 the older ISA bus. The EISA bus saw limited use between 1988 and
2049 1995 when it was made obsolete by the PCI bus.
2051 Say Y here if you are building a kernel for an EISA-based machine.
2055 source "drivers/eisa/Kconfig"
2060 MicroChannel Architecture is found in some IBM PS/2 machines and
2061 laptops. It is a bus system similar to PCI or ISA. See
2062 <file:Documentation/mca.txt> (and especially the web page given
2063 there) before attempting to build an MCA bus kernel.
2065 source "drivers/mca/Kconfig"
2068 tristate "NatSemi SCx200 support"
2070 This provides basic support for National Semiconductor's
2071 (now AMD's) Geode processors. The driver probes for the
2072 PCI-IDs of several on-chip devices, so its a good dependency
2073 for other scx200_* drivers.
2075 If compiled as a module, the driver is named scx200.
2077 config SCx200HR_TIMER
2078 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2082 This driver provides a clocksource built upon the on-chip
2083 27MHz high-resolution timer. Its also a workaround for
2084 NSC Geode SC-1100's buggy TSC, which loses time when the
2085 processor goes idle (as is done by the scheduler). The
2086 other workaround is idle=poll boot option.
2089 bool "One Laptop Per Child support"
2092 Add support for detecting the unique features of the OLPC
2095 config OLPC_OPENFIRMWARE
2096 bool "Support for OLPC's Open Firmware"
2097 depends on !X86_64 && !X86_PAE
2100 This option adds support for the implementation of Open Firmware
2101 that is used on the OLPC XO-1 Children's Machine.
2102 If unsure, say N here.
2108 depends on CPU_SUP_AMD && PCI
2110 source "drivers/pcmcia/Kconfig"
2112 source "drivers/pci/hotplug/Kconfig"
2117 menu "Executable file formats / Emulations"
2119 source "fs/Kconfig.binfmt"
2121 config IA32_EMULATION
2122 bool "IA32 Emulation"
2124 select COMPAT_BINFMT_ELF
2126 Include code to run 32-bit programs under a 64-bit kernel. You should
2127 likely turn this on, unless you're 100% sure that you don't have any
2128 32-bit programs left.
2131 tristate "IA32 a.out support"
2132 depends on IA32_EMULATION
2134 Support old a.out binaries in the 32bit emulation.
2138 depends on IA32_EMULATION
2140 config COMPAT_FOR_U64_ALIGNMENT
2144 config SYSVIPC_COMPAT
2146 depends on COMPAT && SYSVIPC
2151 config HAVE_ATOMIC_IOMAP
2155 config HAVE_TEXT_POKE_SMP
2157 select STOP_MACHINE if SMP
2159 source "net/Kconfig"
2161 source "drivers/Kconfig"
2163 source "drivers/firmware/Kconfig"
2167 source "arch/x86/Kconfig.debug"
2169 source "security/Kconfig"
2171 source "crypto/Kconfig"
2173 source "arch/x86/kvm/Kconfig"
2175 source "lib/Kconfig"
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