2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PERF_EVENTS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
35 select HAVE_FTRACE_MCOUNT_RECORD
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
56 select HAVE_MIXED_BREAKPOINTS_REGS
58 select HAVE_PERF_EVENTS_NMI
60 select HAVE_ARCH_KMEMCHECK
61 select HAVE_USER_RETURN_NOTIFIER
62 select HAVE_ARCH_JUMP_LABEL
63 select HAVE_TEXT_POKE_SMP
65 config INSTRUCTION_DECODER
66 def_bool (KPROBES || PERF_EVENTS)
70 default "elf32-i386" if X86_32
71 default "elf64-x86-64" if X86_64
75 default "arch/x86/configs/i386_defconfig" if X86_32
76 default "arch/x86/configs/x86_64_defconfig" if X86_64
78 config GENERIC_CMOS_UPDATE
81 config CLOCKSOURCE_WATCHDOG
84 config GENERIC_CLOCKEVENTS
87 config GENERIC_CLOCKEVENTS_BROADCAST
89 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
91 config LOCKDEP_SUPPORT
94 config STACKTRACE_SUPPORT
97 config HAVE_LATENCYTOP_SUPPORT
109 config NEED_DMA_MAP_STATE
110 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
112 config NEED_SG_DMA_LENGTH
115 config GENERIC_ISA_DMA
124 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
126 config GENERIC_BUG_RELATIVE_POINTERS
129 config GENERIC_HWEIGHT
135 config ARCH_MAY_HAVE_PC_FDC
138 config RWSEM_GENERIC_SPINLOCK
141 config RWSEM_XCHGADD_ALGORITHM
144 config ARCH_HAS_CPU_IDLE_WAIT
147 config GENERIC_CALIBRATE_DELAY
150 config GENERIC_TIME_VSYSCALL
154 config ARCH_HAS_CPU_RELAX
157 config ARCH_HAS_DEFAULT_IDLE
160 config ARCH_HAS_CACHE_LINE_SIZE
163 config HAVE_SETUP_PER_CPU_AREA
166 config NEED_PER_CPU_EMBED_FIRST_CHUNK
169 config NEED_PER_CPU_PAGE_FIRST_CHUNK
172 config HAVE_CPUMASK_OF_CPU_MAP
175 config ARCH_HIBERNATION_POSSIBLE
178 config ARCH_SUSPEND_POSSIBLE
185 config ARCH_POPULATES_NODE_MAP
192 config ARCH_SUPPORTS_OPTIMIZED_INLINING
195 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
198 config HAVE_EARLY_RES
201 config HAVE_INTEL_TXT
203 depends on EXPERIMENTAL && DMAR && ACPI
205 # Use the generic interrupt handling code in kernel/irq/:
206 config GENERIC_HARDIRQS
209 config GENERIC_HARDIRQS_NO__DO_IRQ
212 config GENERIC_IRQ_PROBE
215 config GENERIC_PENDING_IRQ
217 depends on GENERIC_HARDIRQS && SMP
219 config USE_GENERIC_SMP_HELPERS
225 depends on X86_32 && SMP
229 depends on X86_64 && SMP
235 config X86_TRAMPOLINE
237 depends on SMP || (64BIT && ACPI_SLEEP)
239 config X86_32_LAZY_GS
241 depends on X86_32 && !CC_STACKPROTECTOR
243 config ARCH_HWEIGHT_CFLAGS
245 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
246 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
251 config ARCH_CPU_PROBE_RELEASE
253 depends on HOTPLUG_CPU
255 source "init/Kconfig"
256 source "kernel/Kconfig.freezer"
258 menu "Processor type and features"
260 source "kernel/time/Kconfig"
263 bool "Symmetric multi-processing support"
265 This enables support for systems with more than one CPU. If you have
266 a system with only one CPU, like most personal computers, say N. If
267 you have a system with more than one CPU, say Y.
269 If you say N here, the kernel will run on single and multiprocessor
270 machines, but will use only one CPU of a multiprocessor machine. If
271 you say Y here, the kernel will run on many, but not all,
272 singleprocessor machines. On a singleprocessor machine, the kernel
273 will run faster if you say N here.
275 Note that if you say Y here and choose architecture "586" or
276 "Pentium" under "Processor family", the kernel will not work on 486
277 architectures. Similarly, multiprocessor kernels for the "PPro"
278 architecture may not work on all Pentium based boards.
280 People using multiprocessor machines who say Y here should also say
281 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
282 Management" code will be disabled if you say Y here.
284 See also <file:Documentation/i386/IO-APIC.txt>,
285 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
286 <http://www.tldp.org/docs.html#howto>.
288 If you don't know what to do here, say N.
291 bool "Support x2apic"
292 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
294 This enables x2apic support on CPUs that have this feature.
296 This allows 32-bit apic IDs (so it can support very large systems),
297 and accesses the local apic via MSRs not via mmio.
299 If you don't know what to do here, say N.
302 bool "Support sparse irq numbering"
303 depends on PCI_MSI || HT_IRQ
305 This enables support for sparse irqs. This is useful for distro
306 kernels that want to define a high CONFIG_NR_CPUS value but still
307 want to have low kernel memory footprint on smaller machines.
309 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
310 out the irq_desc[] array in a more NUMA-friendly way. )
312 If you don't know what to do here, say N.
316 depends on SPARSE_IRQ && NUMA
319 bool "Enable MPS table" if ACPI
321 depends on X86_LOCAL_APIC
323 For old smp systems that do not have proper acpi support. Newer systems
324 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
327 bool "Support for big SMP systems with more than 8 CPUs"
328 depends on X86_32 && SMP
330 This option is needed for the systems that have more than 8 CPUs
333 config X86_EXTENDED_PLATFORM
334 bool "Support for extended (non-PC) x86 platforms"
337 If you disable this option then the kernel will only support
338 standard PC platforms. (which covers the vast majority of
341 If you enable this option then you'll be able to select support
342 for the following (non-PC) 32 bit x86 platforms:
346 SGI 320/540 (Visual Workstation)
347 Summit/EXA (IBM x440)
348 Unisys ES7000 IA32 series
349 Moorestown MID devices
351 If you have one of these systems, or if you want to build a
352 generic distribution kernel, say Y here - otherwise say N.
356 config X86_EXTENDED_PLATFORM
357 bool "Support for extended (non-PC) x86 platforms"
360 If you disable this option then the kernel will only support
361 standard PC platforms. (which covers the vast majority of
364 If you enable this option then you'll be able to select support
365 for the following (non-PC) 64 bit x86 platforms:
369 If you have one of these systems, or if you want to build a
370 generic distribution kernel, say Y here - otherwise say N.
372 # This is an alphabetically sorted list of 64 bit extended platforms
373 # Please maintain the alphabetic order if and when there are additions
378 depends on X86_64 && PCI
379 depends on X86_EXTENDED_PLATFORM
381 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
382 supposed to run on these EM64T-based machines. Only choose this option
383 if you have one of these machines.
386 bool "SGI Ultraviolet"
388 depends on X86_EXTENDED_PLATFORM
390 depends on X86_X2APIC
392 This option is needed in order to support SGI Ultraviolet systems.
393 If you don't have one of these, you should say N here.
395 # Following is an alphabetically sorted list of 32 bit extended platforms
396 # Please maintain the alphabetic order if and when there are additions
401 depends on X86_EXTENDED_PLATFORM
403 Select this for an AMD Elan processor.
405 Do not use this option for K6/Athlon/Opteron processors!
407 If unsure, choose "PC-compatible" instead.
410 bool "Moorestown MID platform"
414 depends on X86_EXTENDED_PLATFORM
415 depends on X86_IO_APIC
418 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
419 Internet Device(MID) platform. Moorestown consists of two chips:
420 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
421 Unlike standard x86 PCs, Moorestown does not have many legacy devices
422 nor standard legacy replacement devices/features. e.g. Moorestown does
423 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
426 bool "RDC R-321x SoC"
428 depends on X86_EXTENDED_PLATFORM
430 select X86_REBOOTFIXUPS
432 This option is needed for RDC R-321x system-on-chip, also known
434 If you don't have one of these chips, you should say N here.
436 config X86_32_NON_STANDARD
437 bool "Support non-standard 32-bit SMP architectures"
438 depends on X86_32 && SMP
439 depends on X86_EXTENDED_PLATFORM
441 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
442 subarchitectures. It is intended for a generic binary kernel.
443 if you select them all, kernel will probe it one by one. and will
446 # Alphabetically sorted list of Non standard 32 bit platforms
449 bool "NUMAQ (IBM/Sequent)"
450 depends on X86_32_NON_STANDARD
455 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
456 NUMA multiquad box. This changes the way that processors are
457 bootstrapped, and uses Clustered Logical APIC addressing mode instead
458 of Flat Logical. You will need a new lynxer.elf file to flash your
459 firmware with - send email to <Martin.Bligh@us.ibm.com>.
461 config X86_SUPPORTS_MEMORY_FAILURE
463 # MCE code calls memory_failure():
465 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
466 depends on !X86_NUMAQ
467 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
468 depends on X86_64 || !SPARSEMEM
469 select ARCH_SUPPORTS_MEMORY_FAILURE
472 bool "SGI 320/540 (Visual Workstation)"
473 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
474 depends on X86_32_NON_STANDARD
476 The SGI Visual Workstation series is an IA32-based workstation
477 based on SGI systems chips with some legacy PC hardware attached.
479 Say Y here to create a kernel to run on the SGI 320 or 540.
481 A kernel compiled for the Visual Workstation will run on general
482 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
485 bool "Summit/EXA (IBM x440)"
486 depends on X86_32_NON_STANDARD
488 This option is needed for IBM systems that use the Summit/EXA chipset.
489 In particular, it is needed for the x440.
492 bool "Unisys ES7000 IA32 series"
493 depends on X86_32_NON_STANDARD && X86_BIGSMP
495 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
496 supposed to run on an IA32-based Unisys ES7000 system.
498 config SCHED_OMIT_FRAME_POINTER
500 prompt "Single-depth WCHAN output"
503 Calculate simpler /proc/<PID>/wchan values. If this option
504 is disabled then wchan values will recurse back to the
505 caller function. This provides more accurate wchan values,
506 at the expense of slightly more scheduling overhead.
508 If in doubt, say "Y".
510 menuconfig PARAVIRT_GUEST
511 bool "Paravirtualized guest support"
513 Say Y here to get to see options related to running Linux under
514 various hypervisors. This option alone does not add any kernel code.
516 If you say N, all options in this submenu will be skipped and disabled.
520 source "arch/x86/xen/Kconfig"
523 bool "VMI Guest support (DEPRECATED)"
527 VMI provides a paravirtualized interface to the VMware ESX server
528 (it could be used by other hypervisors in theory too, but is not
529 at the moment), by linking the kernel to a GPL-ed ROM module
530 provided by the hypervisor.
532 As of September 2009, VMware has started a phased retirement
533 of this feature from VMware's products. Please see
534 feature-removal-schedule.txt for details. If you are
535 planning to enable this option, please note that you cannot
536 live migrate a VMI enabled VM to a future VMware product,
537 which doesn't support VMI. So if you expect your kernel to
538 seamlessly migrate to newer VMware products, keep this
542 bool "KVM paravirtualized clock"
544 select PARAVIRT_CLOCK
546 Turning on this option will allow you to run a paravirtualized clock
547 when running over the KVM hypervisor. Instead of relying on a PIT
548 (or probably other) emulation by the underlying device model, the host
549 provides the guest with timing infrastructure such as time of day, and
553 bool "KVM Guest support"
556 This option enables various optimizations for running under the KVM
559 source "arch/x86/lguest/Kconfig"
562 bool "Enable paravirtualization code"
564 This changes the kernel so it can modify itself when it is run
565 under a hypervisor, potentially improving performance significantly
566 over full virtualization. However, when run without a hypervisor
567 the kernel is theoretically slower and slightly larger.
569 config PARAVIRT_SPINLOCKS
570 bool "Paravirtualization layer for spinlocks"
571 depends on PARAVIRT && SMP && EXPERIMENTAL
573 Paravirtualized spinlocks allow a pvops backend to replace the
574 spinlock implementation with something virtualization-friendly
575 (for example, block the virtual CPU rather than spinning).
577 Unfortunately the downside is an up to 5% performance hit on
578 native kernels, with various workloads.
580 If you are unsure how to answer this question, answer N.
582 config PARAVIRT_CLOCK
587 config PARAVIRT_DEBUG
588 bool "paravirt-ops debugging"
589 depends on PARAVIRT && DEBUG_KERNEL
591 Enable to debug paravirt_ops internals. Specifically, BUG if
592 a paravirt_op is missing when it is called.
596 bool "Disable Bootmem code"
598 Use early_res directly instead of bootmem before slab is ready.
599 - allocator (buddy) [generic]
600 - early allocator (bootmem) [generic]
601 - very early allocator (reserve_early*()) [x86]
602 - very very early allocator (early brk model) [x86]
603 So reduce one layer between early allocator to final allocator
609 This option adds a kernel parameter 'memtest', which allows memtest
611 memtest=0, mean disabled; -- default
612 memtest=1, mean do 1 test pattern;
614 memtest=4, mean do 4 test patterns.
615 If you are unsure how to answer this question, answer N.
617 config X86_SUMMIT_NUMA
619 depends on X86_32 && NUMA && X86_32_NON_STANDARD
621 config X86_CYCLONE_TIMER
623 depends on X86_32_NON_STANDARD
625 source "arch/x86/Kconfig.cpu"
629 prompt "HPET Timer Support" if X86_32
631 Use the IA-PC HPET (High Precision Event Timer) to manage
632 time in preference to the PIT and RTC, if a HPET is
634 HPET is the next generation timer replacing legacy 8254s.
635 The HPET provides a stable time base on SMP
636 systems, unlike the TSC, but it is more expensive to access,
637 as it is off-chip. You can find the HPET spec at
638 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
640 You can safely choose Y here. However, HPET will only be
641 activated if the platform and the BIOS support this feature.
642 Otherwise the 8254 will be used for timing services.
644 Choose N to continue using the legacy 8254 timer.
646 config HPET_EMULATE_RTC
648 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
652 prompt "Langwell APB Timer Support" if X86_MRST
654 APB timer is the replacement for 8254, HPET on X86 MID platforms.
655 The APBT provides a stable time base on SMP
656 systems, unlike the TSC, but it is more expensive to access,
657 as it is off-chip. APB timers are always running regardless of CPU
658 C states, they are used as per CPU clockevent device when possible.
660 # Mark as embedded because too many people got it wrong.
661 # The code disables itself when not needed.
664 bool "Enable DMI scanning" if EMBEDDED
666 Enabled scanning of DMI to identify machine quirks. Say Y
667 here unless you have verified that your setup is not
668 affected by entries in the DMI blacklist. Required by PNP
672 bool "GART IOMMU support" if EMBEDDED
675 depends on X86_64 && PCI && K8_NB
677 Support for full DMA access of devices with 32bit memory access only
678 on systems with more than 3GB. This is usually needed for USB,
679 sound, many IDE/SATA chipsets and some other devices.
680 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
681 based hardware IOMMU and a software bounce buffer based IOMMU used
682 on Intel systems and as fallback.
683 The code is only active when needed (enough memory and limited
684 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
688 bool "IBM Calgary IOMMU support"
690 depends on X86_64 && PCI && EXPERIMENTAL
692 Support for hardware IOMMUs in IBM's xSeries x366 and x460
693 systems. Needed to run systems with more than 3GB of memory
694 properly with 32-bit PCI devices that do not support DAC
695 (Double Address Cycle). Calgary also supports bus level
696 isolation, where all DMAs pass through the IOMMU. This
697 prevents them from going anywhere except their intended
698 destination. This catches hard-to-find kernel bugs and
699 mis-behaving drivers and devices that do not use the DMA-API
700 properly to set up their DMA buffers. The IOMMU can be
701 turned off at boot time with the iommu=off parameter.
702 Normally the kernel will make the right choice by itself.
705 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
707 prompt "Should Calgary be enabled by default?"
708 depends on CALGARY_IOMMU
710 Should Calgary be enabled by default? if you choose 'y', Calgary
711 will be used (if it exists). If you choose 'n', Calgary will not be
712 used even if it exists. If you choose 'n' and would like to use
713 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
717 bool "AMD IOMMU support"
720 depends on X86_64 && PCI && ACPI
722 With this option you can enable support for AMD IOMMU hardware in
723 your system. An IOMMU is a hardware component which provides
724 remapping of DMA memory accesses from devices. With an AMD IOMMU you
725 can isolate the the DMA memory of different devices and protect the
726 system from misbehaving device drivers or hardware.
728 You can find out if your system has an AMD IOMMU if you look into
729 your BIOS for an option to enable it or if you have an IVRS ACPI
732 config AMD_IOMMU_STATS
733 bool "Export AMD IOMMU statistics to debugfs"
737 This option enables code in the AMD IOMMU driver to collect various
738 statistics about whats happening in the driver and exports that
739 information to userspace via debugfs.
742 # need this always selected by IOMMU for the VIA workaround
746 Support for software bounce buffers used on x86-64 systems
747 which don't have a hardware IOMMU (e.g. the current generation
748 of Intel's x86-64 CPUs). Using this PCI devices which can only
749 access 32-bits of memory can be used on systems with more than
750 3 GB of memory. If unsure, say Y.
753 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
756 def_bool (AMD_IOMMU || DMAR)
759 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
760 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
761 select CPUMASK_OFFSTACK
763 Enable maximum number of CPUS and NUMA Nodes for this architecture.
767 int "Maximum number of CPUs" if SMP && !MAXSMP
768 range 2 8 if SMP && X86_32 && !X86_BIGSMP
769 range 2 512 if SMP && !MAXSMP
771 default "4096" if MAXSMP
772 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
775 This allows you to specify the maximum number of CPUs which this
776 kernel will support. The maximum supported value is 512 and the
777 minimum value which makes sense is 2.
779 This is purely to save memory - each supported CPU adds
780 approximately eight kilobytes to the kernel image.
783 bool "SMT (Hyperthreading) scheduler support"
786 SMT scheduler support improves the CPU scheduler's decision making
787 when dealing with Intel Pentium 4 chips with HyperThreading at a
788 cost of slightly increased overhead in some places. If unsure say
793 prompt "Multi-core scheduler support"
796 Multi-core scheduler support improves the CPU scheduler's decision
797 making when dealing with multi-core CPU chips at a cost of slightly
798 increased overhead in some places. If unsure say N here.
800 source "kernel/Kconfig.preempt"
803 bool "Local APIC support on uniprocessors"
804 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
806 A local APIC (Advanced Programmable Interrupt Controller) is an
807 integrated interrupt controller in the CPU. If you have a single-CPU
808 system which has a processor with a local APIC, you can say Y here to
809 enable and use it. If you say Y here even though your machine doesn't
810 have a local APIC, then the kernel will still run with no slowdown at
811 all. The local APIC supports CPU-generated self-interrupts (timer,
812 performance counters), and the NMI watchdog which detects hard
816 bool "IO-APIC support on uniprocessors"
817 depends on X86_UP_APIC
819 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
820 SMP-capable replacement for PC-style interrupt controllers. Most
821 SMP systems and many recent uniprocessor systems have one.
823 If you have a single-CPU system with an IO-APIC, you can say Y here
824 to use it. If you say Y here even though your machine doesn't have
825 an IO-APIC, then the kernel will still run with no slowdown at all.
827 config X86_LOCAL_APIC
829 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
833 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
835 config X86_VISWS_APIC
837 depends on X86_32 && X86_VISWS
839 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
840 bool "Reroute for broken boot IRQs"
841 depends on X86_IO_APIC
843 This option enables a workaround that fixes a source of
844 spurious interrupts. This is recommended when threaded
845 interrupt handling is used on systems where the generation of
846 superfluous "boot interrupts" cannot be disabled.
848 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
849 entry in the chipset's IO-APIC is masked (as, e.g. the RT
850 kernel does during interrupt handling). On chipsets where this
851 boot IRQ generation cannot be disabled, this workaround keeps
852 the original IRQ line masked so that only the equivalent "boot
853 IRQ" is delivered to the CPUs. The workaround also tells the
854 kernel to set up the IRQ handler on the boot IRQ line. In this
855 way only one interrupt is delivered to the kernel. Otherwise
856 the spurious second interrupt may cause the kernel to bring
857 down (vital) interrupt lines.
859 Only affects "broken" chipsets. Interrupt sharing may be
860 increased on these systems.
863 bool "Machine Check / overheating reporting"
865 Machine Check support allows the processor to notify the
866 kernel if it detects a problem (e.g. overheating, data corruption).
867 The action the kernel takes depends on the severity of the problem,
868 ranging from warning messages to halting the machine.
872 prompt "Intel MCE features"
873 depends on X86_MCE && X86_LOCAL_APIC
875 Additional support for intel specific MCE features such as
880 prompt "AMD MCE features"
881 depends on X86_MCE && X86_LOCAL_APIC
883 Additional support for AMD specific MCE features such as
884 the DRAM Error Threshold.
886 config X86_ANCIENT_MCE
887 bool "Support for old Pentium 5 / WinChip machine checks"
888 depends on X86_32 && X86_MCE
890 Include support for machine check handling on old Pentium 5 or WinChip
891 systems. These typically need to be enabled explicitely on the command
894 config X86_MCE_THRESHOLD
895 depends on X86_MCE_AMD || X86_MCE_INTEL
898 config X86_MCE_INJECT
900 tristate "Machine check injector support"
902 Provide support for injecting machine checks for testing purposes.
903 If you don't know what a machine check is and you don't do kernel
904 QA it is safe to say n.
906 config X86_THERMAL_VECTOR
908 depends on X86_MCE_INTEL
911 bool "Enable VM86 support" if EMBEDDED
915 This option is required by programs like DOSEMU to run 16-bit legacy
916 code on X86 processors. It also may be needed by software like
917 XFree86 to initialize some video cards via BIOS. Disabling this
918 option saves about 6k.
921 tristate "Toshiba Laptop support"
924 This adds a driver to safely access the System Management Mode of
925 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
926 not work on models with a Phoenix BIOS. The System Management Mode
927 is used to set the BIOS and power saving options on Toshiba portables.
929 For information on utilities to make use of this driver see the
930 Toshiba Linux utilities web site at:
931 <http://www.buzzard.org.uk/toshiba/>.
933 Say Y if you intend to run this kernel on a Toshiba portable.
937 tristate "Dell laptop support"
939 This adds a driver to safely access the System Management Mode
940 of the CPU on the Dell Inspiron 8000. The System Management Mode
941 is used to read cpu temperature and cooling fan status and to
942 control the fans on the I8K portables.
944 This driver has been tested only on the Inspiron 8000 but it may
945 also work with other Dell laptops. You can force loading on other
946 models by passing the parameter `force=1' to the module. Use at
949 For information on utilities to make use of this driver see the
950 I8K Linux utilities web site at:
951 <http://people.debian.org/~dz/i8k/>
953 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
956 config X86_REBOOTFIXUPS
957 bool "Enable X86 board specific fixups for reboot"
960 This enables chipset and/or board specific fixups to be done
961 in order to get reboot to work correctly. This is only needed on
962 some combinations of hardware and BIOS. The symptom, for which
963 this config is intended, is when reboot ends with a stalled/hung
966 Currently, the only fixup is for the Geode machines using
967 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
969 Say Y if you want to enable the fixup. Currently, it's safe to
970 enable this option even if you don't need it.
974 tristate "/dev/cpu/microcode - microcode support"
977 If you say Y here, you will be able to update the microcode on
978 certain Intel and AMD processors. The Intel support is for the
979 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
980 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
981 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
982 You will obviously need the actual microcode binary data itself
983 which is not shipped with the Linux kernel.
985 This option selects the general module only, you need to select
986 at least one vendor specific module as well.
988 To compile this driver as a module, choose M here: the
989 module will be called microcode.
991 config MICROCODE_INTEL
992 bool "Intel microcode patch loading support"
997 This options enables microcode patch loading support for Intel
1000 For latest news and information on obtaining all the required
1001 Intel ingredients for this driver, check:
1002 <http://www.urbanmyth.org/microcode/>.
1004 config MICROCODE_AMD
1005 bool "AMD microcode patch loading support"
1006 depends on MICROCODE
1009 If you select this option, microcode patch loading support for AMD
1010 processors will be enabled.
1012 config MICROCODE_OLD_INTERFACE
1014 depends on MICROCODE
1017 tristate "/dev/cpu/*/msr - Model-specific register support"
1019 This device gives privileged processes access to the x86
1020 Model-Specific Registers (MSRs). It is a character device with
1021 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1022 MSR accesses are directed to a specific CPU on multi-processor
1026 tristate "/dev/cpu/*/cpuid - CPU information support"
1028 This device gives processes access to the x86 CPUID instruction to
1029 be executed on a specific processor. It is a character device
1030 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1034 prompt "High Memory Support"
1035 default HIGHMEM64G if X86_NUMAQ
1041 depends on !X86_NUMAQ
1043 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1044 However, the address space of 32-bit x86 processors is only 4
1045 Gigabytes large. That means that, if you have a large amount of
1046 physical memory, not all of it can be "permanently mapped" by the
1047 kernel. The physical memory that's not permanently mapped is called
1050 If you are compiling a kernel which will never run on a machine with
1051 more than 1 Gigabyte total physical RAM, answer "off" here (default
1052 choice and suitable for most users). This will result in a "3GB/1GB"
1053 split: 3GB are mapped so that each process sees a 3GB virtual memory
1054 space and the remaining part of the 4GB virtual memory space is used
1055 by the kernel to permanently map as much physical memory as
1058 If the machine has between 1 and 4 Gigabytes physical RAM, then
1061 If more than 4 Gigabytes is used then answer "64GB" here. This
1062 selection turns Intel PAE (Physical Address Extension) mode on.
1063 PAE implements 3-level paging on IA32 processors. PAE is fully
1064 supported by Linux, PAE mode is implemented on all recent Intel
1065 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1066 then the kernel will not boot on CPUs that don't support PAE!
1068 The actual amount of total physical memory will either be
1069 auto detected or can be forced by using a kernel command line option
1070 such as "mem=256M". (Try "man bootparam" or see the documentation of
1071 your boot loader (lilo or loadlin) about how to pass options to the
1072 kernel at boot time.)
1074 If unsure, say "off".
1078 depends on !X86_NUMAQ
1080 Select this if you have a 32-bit processor and between 1 and 4
1081 gigabytes of physical RAM.
1085 depends on !M386 && !M486
1088 Select this if you have a 32-bit processor and more than 4
1089 gigabytes of physical RAM.
1094 depends on EXPERIMENTAL
1095 prompt "Memory split" if EMBEDDED
1099 Select the desired split between kernel and user memory.
1101 If the address range available to the kernel is less than the
1102 physical memory installed, the remaining memory will be available
1103 as "high memory". Accessing high memory is a little more costly
1104 than low memory, as it needs to be mapped into the kernel first.
1105 Note that increasing the kernel address space limits the range
1106 available to user programs, making the address space there
1107 tighter. Selecting anything other than the default 3G/1G split
1108 will also likely make your kernel incompatible with binary-only
1111 If you are not absolutely sure what you are doing, leave this
1115 bool "3G/1G user/kernel split"
1116 config VMSPLIT_3G_OPT
1118 bool "3G/1G user/kernel split (for full 1G low memory)"
1120 bool "2G/2G user/kernel split"
1121 config VMSPLIT_2G_OPT
1123 bool "2G/2G user/kernel split (for full 2G low memory)"
1125 bool "1G/3G user/kernel split"
1130 default 0xB0000000 if VMSPLIT_3G_OPT
1131 default 0x80000000 if VMSPLIT_2G
1132 default 0x78000000 if VMSPLIT_2G_OPT
1133 default 0x40000000 if VMSPLIT_1G
1139 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1142 bool "PAE (Physical Address Extension) Support"
1143 depends on X86_32 && !HIGHMEM4G
1145 PAE is required for NX support, and furthermore enables
1146 larger swapspace support for non-overcommit purposes. It
1147 has the cost of more pagetable lookup overhead, and also
1148 consumes more pagetable space per process.
1150 config ARCH_PHYS_ADDR_T_64BIT
1151 def_bool X86_64 || X86_PAE
1153 config DIRECT_GBPAGES
1154 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1158 Allow the kernel linear mapping to use 1GB pages on CPUs that
1159 support it. This can improve the kernel's performance a tiny bit by
1160 reducing TLB pressure. If in doubt, say "Y".
1162 # Common NUMA Features
1164 bool "Numa Memory Allocation and Scheduler Support"
1166 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1167 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1169 Enable NUMA (Non Uniform Memory Access) support.
1171 The kernel will try to allocate memory used by a CPU on the
1172 local memory controller of the CPU and add some more
1173 NUMA awareness to the kernel.
1175 For 64-bit this is recommended if the system is Intel Core i7
1176 (or later), AMD Opteron, or EM64T NUMA.
1178 For 32-bit this is only needed on (rare) 32-bit-only platforms
1179 that support NUMA topologies, such as NUMAQ / Summit, or if you
1180 boot a 32-bit kernel on a 64-bit NUMA platform.
1182 Otherwise, you should say N.
1184 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1185 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1189 prompt "Old style AMD Opteron NUMA detection"
1190 depends on X86_64 && NUMA && PCI
1192 Enable K8 NUMA node topology detection. You should say Y here if
1193 you have a multi processor AMD K8 system. This uses an old
1194 method to read the NUMA configuration directly from the builtin
1195 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1196 instead, which also takes priority if both are compiled in.
1198 config X86_64_ACPI_NUMA
1200 prompt "ACPI NUMA detection"
1201 depends on X86_64 && NUMA && ACPI && PCI
1204 Enable ACPI SRAT based node topology detection.
1206 # Some NUMA nodes have memory ranges that span
1207 # other nodes. Even though a pfn is valid and
1208 # between a node's start and end pfns, it may not
1209 # reside on that node. See memmap_init_zone()
1211 config NODES_SPAN_OTHER_NODES
1213 depends on X86_64_ACPI_NUMA
1216 bool "NUMA emulation"
1217 depends on X86_64 && NUMA
1219 Enable NUMA emulation. A flat machine will be split
1220 into virtual nodes when booted with "numa=fake=N", where N is the
1221 number of nodes. This is only useful for debugging.
1224 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1226 default "10" if MAXSMP
1227 default "6" if X86_64
1228 default "4" if X86_NUMAQ
1230 depends on NEED_MULTIPLE_NODES
1232 Specify the maximum number of NUMA Nodes available on the target
1233 system. Increases memory reserved to accommodate various tables.
1235 config HAVE_ARCH_BOOTMEM
1237 depends on X86_32 && NUMA
1239 config ARCH_HAVE_MEMORY_PRESENT
1241 depends on X86_32 && DISCONTIGMEM
1243 config NEED_NODE_MEMMAP_SIZE
1245 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1247 config HAVE_ARCH_ALLOC_REMAP
1249 depends on X86_32 && NUMA
1251 config ARCH_FLATMEM_ENABLE
1253 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1255 config ARCH_DISCONTIGMEM_ENABLE
1257 depends on NUMA && X86_32
1259 config ARCH_DISCONTIGMEM_DEFAULT
1261 depends on NUMA && X86_32
1263 config ARCH_PROC_KCORE_TEXT
1265 depends on X86_64 && PROC_KCORE
1267 config ARCH_SPARSEMEM_DEFAULT
1271 config ARCH_SPARSEMEM_ENABLE
1273 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1274 select SPARSEMEM_STATIC if X86_32
1275 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1277 config ARCH_SELECT_MEMORY_MODEL
1279 depends on ARCH_SPARSEMEM_ENABLE
1281 config ARCH_MEMORY_PROBE
1283 depends on MEMORY_HOTPLUG
1285 config ILLEGAL_POINTER_VALUE
1288 default 0xdead000000000000 if X86_64
1293 bool "Allocate 3rd-level pagetables from highmem"
1296 The VM uses one page table entry for each page of physical memory.
1297 For systems with a lot of RAM, this can be wasteful of precious
1298 low memory. Setting this option will put user-space page table
1299 entries in high memory.
1301 config X86_CHECK_BIOS_CORRUPTION
1302 bool "Check for low memory corruption"
1304 Periodically check for memory corruption in low memory, which
1305 is suspected to be caused by BIOS. Even when enabled in the
1306 configuration, it is disabled at runtime. Enable it by
1307 setting "memory_corruption_check=1" on the kernel command
1308 line. By default it scans the low 64k of memory every 60
1309 seconds; see the memory_corruption_check_size and
1310 memory_corruption_check_period parameters in
1311 Documentation/kernel-parameters.txt to adjust this.
1313 When enabled with the default parameters, this option has
1314 almost no overhead, as it reserves a relatively small amount
1315 of memory and scans it infrequently. It both detects corruption
1316 and prevents it from affecting the running system.
1318 It is, however, intended as a diagnostic tool; if repeatable
1319 BIOS-originated corruption always affects the same memory,
1320 you can use memmap= to prevent the kernel from using that
1323 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1324 bool "Set the default setting of memory_corruption_check"
1325 depends on X86_CHECK_BIOS_CORRUPTION
1328 Set whether the default state of memory_corruption_check is
1331 config X86_RESERVE_LOW_64K
1332 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1335 Reserve the first 64K of physical RAM on BIOSes that are known
1336 to potentially corrupt that memory range. A numbers of BIOSes are
1337 known to utilize this area during suspend/resume, so it must not
1338 be used by the kernel.
1340 Set this to N if you are absolutely sure that you trust the BIOS
1341 to get all its memory reservations and usages right.
1343 If you have doubts about the BIOS (e.g. suspend/resume does not
1344 work or there's kernel crashes after certain hardware hotplug
1345 events) and it's not AMI or Phoenix, then you might want to enable
1346 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1347 corruption patterns.
1351 config MATH_EMULATION
1353 prompt "Math emulation" if X86_32
1355 Linux can emulate a math coprocessor (used for floating point
1356 operations) if you don't have one. 486DX and Pentium processors have
1357 a math coprocessor built in, 486SX and 386 do not, unless you added
1358 a 487DX or 387, respectively. (The messages during boot time can
1359 give you some hints here ["man dmesg"].) Everyone needs either a
1360 coprocessor or this emulation.
1362 If you don't have a math coprocessor, you need to say Y here; if you
1363 say Y here even though you have a coprocessor, the coprocessor will
1364 be used nevertheless. (This behavior can be changed with the kernel
1365 command line option "no387", which comes handy if your coprocessor
1366 is broken. Try "man bootparam" or see the documentation of your boot
1367 loader (lilo or loadlin) about how to pass options to the kernel at
1368 boot time.) This means that it is a good idea to say Y here if you
1369 intend to use this kernel on different machines.
1371 More information about the internals of the Linux math coprocessor
1372 emulation can be found in <file:arch/x86/math-emu/README>.
1374 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1375 kernel, it won't hurt.
1379 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1381 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1382 the Memory Type Range Registers (MTRRs) may be used to control
1383 processor access to memory ranges. This is most useful if you have
1384 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1385 allows bus write transfers to be combined into a larger transfer
1386 before bursting over the PCI/AGP bus. This can increase performance
1387 of image write operations 2.5 times or more. Saying Y here creates a
1388 /proc/mtrr file which may be used to manipulate your processor's
1389 MTRRs. Typically the X server should use this.
1391 This code has a reasonably generic interface so that similar
1392 control registers on other processors can be easily supported
1395 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1396 Registers (ARRs) which provide a similar functionality to MTRRs. For
1397 these, the ARRs are used to emulate the MTRRs.
1398 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1399 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1400 write-combining. All of these processors are supported by this code
1401 and it makes sense to say Y here if you have one of them.
1403 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1404 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1405 can lead to all sorts of problems, so it's good to say Y here.
1407 You can safely say Y even if your machine doesn't have MTRRs, you'll
1408 just add about 9 KB to your kernel.
1410 See <file:Documentation/x86/mtrr.txt> for more information.
1412 config MTRR_SANITIZER
1414 prompt "MTRR cleanup support"
1417 Convert MTRR layout from continuous to discrete, so X drivers can
1418 add writeback entries.
1420 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1421 The largest mtrr entry size for a continuous block can be set with
1426 config MTRR_SANITIZER_ENABLE_DEFAULT
1427 int "MTRR cleanup enable value (0-1)"
1430 depends on MTRR_SANITIZER
1432 Enable mtrr cleanup default value
1434 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1435 int "MTRR cleanup spare reg num (0-7)"
1438 depends on MTRR_SANITIZER
1440 mtrr cleanup spare entries default, it can be changed via
1441 mtrr_spare_reg_nr=N on the kernel command line.
1445 prompt "x86 PAT support" if EMBEDDED
1448 Use PAT attributes to setup page level cache control.
1450 PATs are the modern equivalents of MTRRs and are much more
1451 flexible than MTRRs.
1453 Say N here if you see bootup problems (boot crash, boot hang,
1454 spontaneous reboots) or a non-working video driver.
1458 config ARCH_USES_PG_UNCACHED
1463 bool "EFI runtime service support"
1466 This enables the kernel to use EFI runtime services that are
1467 available (such as the EFI variable services).
1469 This option is only useful on systems that have EFI firmware.
1470 In addition, you should use the latest ELILO loader available
1471 at <http://elilo.sourceforge.net> in order to take advantage
1472 of EFI runtime services. However, even with this option, the
1473 resultant kernel should continue to boot on existing non-EFI
1478 prompt "Enable seccomp to safely compute untrusted bytecode"
1480 This kernel feature is useful for number crunching applications
1481 that may need to compute untrusted bytecode during their
1482 execution. By using pipes or other transports made available to
1483 the process as file descriptors supporting the read/write
1484 syscalls, it's possible to isolate those applications in
1485 their own address space using seccomp. Once seccomp is
1486 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1487 and the task is only allowed to execute a few safe syscalls
1488 defined by each seccomp mode.
1490 If unsure, say Y. Only embedded should say N here.
1492 config CC_STACKPROTECTOR
1493 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1495 This option turns on the -fstack-protector GCC feature. This
1496 feature puts, at the beginning of functions, a canary value on
1497 the stack just before the return address, and validates
1498 the value just before actually returning. Stack based buffer
1499 overflows (that need to overwrite this return address) now also
1500 overwrite the canary, which gets detected and the attack is then
1501 neutralized via a kernel panic.
1503 This feature requires gcc version 4.2 or above, or a distribution
1504 gcc with the feature backported. Older versions are automatically
1505 detected and for those versions, this configuration option is
1506 ignored. (and a warning is printed during bootup)
1508 source kernel/Kconfig.hz
1511 bool "kexec system call"
1513 kexec is a system call that implements the ability to shutdown your
1514 current kernel, and to start another kernel. It is like a reboot
1515 but it is independent of the system firmware. And like a reboot
1516 you can start any kernel with it, not just Linux.
1518 The name comes from the similarity to the exec system call.
1520 It is an ongoing process to be certain the hardware in a machine
1521 is properly shutdown, so do not be surprised if this code does not
1522 initially work for you. It may help to enable device hotplugging
1523 support. As of this writing the exact hardware interface is
1524 strongly in flux, so no good recommendation can be made.
1527 bool "kernel crash dumps"
1528 depends on X86_64 || (X86_32 && HIGHMEM)
1530 Generate crash dump after being started by kexec.
1531 This should be normally only set in special crash dump kernels
1532 which are loaded in the main kernel with kexec-tools into
1533 a specially reserved region and then later executed after
1534 a crash by kdump/kexec. The crash dump kernel must be compiled
1535 to a memory address not used by the main kernel or BIOS using
1536 PHYSICAL_START, or it must be built as a relocatable image
1537 (CONFIG_RELOCATABLE=y).
1538 For more details see Documentation/kdump/kdump.txt
1541 bool "kexec jump (EXPERIMENTAL)"
1542 depends on EXPERIMENTAL
1543 depends on KEXEC && HIBERNATION
1545 Jump between original kernel and kexeced kernel and invoke
1546 code in physical address mode via KEXEC
1548 config PHYSICAL_START
1549 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1552 This gives the physical address where the kernel is loaded.
1554 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1555 bzImage will decompress itself to above physical address and
1556 run from there. Otherwise, bzImage will run from the address where
1557 it has been loaded by the boot loader and will ignore above physical
1560 In normal kdump cases one does not have to set/change this option
1561 as now bzImage can be compiled as a completely relocatable image
1562 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1563 address. This option is mainly useful for the folks who don't want
1564 to use a bzImage for capturing the crash dump and want to use a
1565 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1566 to be specifically compiled to run from a specific memory area
1567 (normally a reserved region) and this option comes handy.
1569 So if you are using bzImage for capturing the crash dump,
1570 leave the value here unchanged to 0x1000000 and set
1571 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1572 for capturing the crash dump change this value to start of
1573 the reserved region. In other words, it can be set based on
1574 the "X" value as specified in the "crashkernel=YM@XM"
1575 command line boot parameter passed to the panic-ed
1576 kernel. Please take a look at Documentation/kdump/kdump.txt
1577 for more details about crash dumps.
1579 Usage of bzImage for capturing the crash dump is recommended as
1580 one does not have to build two kernels. Same kernel can be used
1581 as production kernel and capture kernel. Above option should have
1582 gone away after relocatable bzImage support is introduced. But it
1583 is present because there are users out there who continue to use
1584 vmlinux for dump capture. This option should go away down the
1587 Don't change this unless you know what you are doing.
1590 bool "Build a relocatable kernel"
1593 This builds a kernel image that retains relocation information
1594 so it can be loaded someplace besides the default 1MB.
1595 The relocations tend to make the kernel binary about 10% larger,
1596 but are discarded at runtime.
1598 One use is for the kexec on panic case where the recovery kernel
1599 must live at a different physical address than the primary
1602 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1603 it has been loaded at and the compile time physical address
1604 (CONFIG_PHYSICAL_START) is ignored.
1606 # Relocation on x86-32 needs some additional build support
1607 config X86_NEED_RELOCS
1609 depends on X86_32 && RELOCATABLE
1611 config PHYSICAL_ALIGN
1612 hex "Alignment value to which kernel should be aligned" if X86_32
1614 range 0x2000 0x1000000
1616 This value puts the alignment restrictions on physical address
1617 where kernel is loaded and run from. Kernel is compiled for an
1618 address which meets above alignment restriction.
1620 If bootloader loads the kernel at a non-aligned address and
1621 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1622 address aligned to above value and run from there.
1624 If bootloader loads the kernel at a non-aligned address and
1625 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1626 load address and decompress itself to the address it has been
1627 compiled for and run from there. The address for which kernel is
1628 compiled already meets above alignment restrictions. Hence the
1629 end result is that kernel runs from a physical address meeting
1630 above alignment restrictions.
1632 Don't change this unless you know what you are doing.
1635 bool "Support for hot-pluggable CPUs"
1636 depends on SMP && HOTPLUG
1638 Say Y here to allow turning CPUs off and on. CPUs can be
1639 controlled through /sys/devices/system/cpu.
1640 ( Note: power management support will enable this option
1641 automatically on SMP systems. )
1642 Say N if you want to disable CPU hotplug.
1646 prompt "Compat VDSO support"
1647 depends on X86_32 || IA32_EMULATION
1649 Map the 32-bit VDSO to the predictable old-style address too.
1651 Say N here if you are running a sufficiently recent glibc
1652 version (2.3.3 or later), to remove the high-mapped
1653 VDSO mapping and to exclusively use the randomized VDSO.
1658 bool "Built-in kernel command line"
1660 Allow for specifying boot arguments to the kernel at
1661 build time. On some systems (e.g. embedded ones), it is
1662 necessary or convenient to provide some or all of the
1663 kernel boot arguments with the kernel itself (that is,
1664 to not rely on the boot loader to provide them.)
1666 To compile command line arguments into the kernel,
1667 set this option to 'Y', then fill in the
1668 the boot arguments in CONFIG_CMDLINE.
1670 Systems with fully functional boot loaders (i.e. non-embedded)
1671 should leave this option set to 'N'.
1674 string "Built-in kernel command string"
1675 depends on CMDLINE_BOOL
1678 Enter arguments here that should be compiled into the kernel
1679 image and used at boot time. If the boot loader provides a
1680 command line at boot time, it is appended to this string to
1681 form the full kernel command line, when the system boots.
1683 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1684 change this behavior.
1686 In most cases, the command line (whether built-in or provided
1687 by the boot loader) should specify the device for the root
1690 config CMDLINE_OVERRIDE
1691 bool "Built-in command line overrides boot loader arguments"
1692 depends on CMDLINE_BOOL
1694 Set this option to 'Y' to have the kernel ignore the boot loader
1695 command line, and use ONLY the built-in command line.
1697 This is used to work around broken boot loaders. This should
1698 be set to 'N' under normal conditions.
1702 config ARCH_ENABLE_MEMORY_HOTPLUG
1704 depends on X86_64 || (X86_32 && HIGHMEM)
1706 config ARCH_ENABLE_MEMORY_HOTREMOVE
1708 depends on MEMORY_HOTPLUG
1710 config HAVE_ARCH_EARLY_PFN_TO_NID
1714 config USE_PERCPU_NUMA_NODE_ID
1718 menu "Power management and ACPI options"
1720 config ARCH_HIBERNATION_HEADER
1722 depends on X86_64 && HIBERNATION
1724 source "kernel/power/Kconfig"
1726 source "drivers/acpi/Kconfig"
1728 source "drivers/sfi/Kconfig"
1732 depends on APM || APM_MODULE
1735 tristate "APM (Advanced Power Management) BIOS support"
1736 depends on X86_32 && PM_SLEEP
1738 APM is a BIOS specification for saving power using several different
1739 techniques. This is mostly useful for battery powered laptops with
1740 APM compliant BIOSes. If you say Y here, the system time will be
1741 reset after a RESUME operation, the /proc/apm device will provide
1742 battery status information, and user-space programs will receive
1743 notification of APM "events" (e.g. battery status change).
1745 If you select "Y" here, you can disable actual use of the APM
1746 BIOS by passing the "apm=off" option to the kernel at boot time.
1748 Note that the APM support is almost completely disabled for
1749 machines with more than one CPU.
1751 In order to use APM, you will need supporting software. For location
1752 and more information, read <file:Documentation/power/pm.txt> and the
1753 Battery Powered Linux mini-HOWTO, available from
1754 <http://www.tldp.org/docs.html#howto>.
1756 This driver does not spin down disk drives (see the hdparm(8)
1757 manpage ("man 8 hdparm") for that), and it doesn't turn off
1758 VESA-compliant "green" monitors.
1760 This driver does not support the TI 4000M TravelMate and the ACER
1761 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1762 desktop machines also don't have compliant BIOSes, and this driver
1763 may cause those machines to panic during the boot phase.
1765 Generally, if you don't have a battery in your machine, there isn't
1766 much point in using this driver and you should say N. If you get
1767 random kernel OOPSes or reboots that don't seem to be related to
1768 anything, try disabling/enabling this option (or disabling/enabling
1771 Some other things you should try when experiencing seemingly random,
1774 1) make sure that you have enough swap space and that it is
1776 2) pass the "no-hlt" option to the kernel
1777 3) switch on floating point emulation in the kernel and pass
1778 the "no387" option to the kernel
1779 4) pass the "floppy=nodma" option to the kernel
1780 5) pass the "mem=4M" option to the kernel (thereby disabling
1781 all but the first 4 MB of RAM)
1782 6) make sure that the CPU is not over clocked.
1783 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1784 8) disable the cache from your BIOS settings
1785 9) install a fan for the video card or exchange video RAM
1786 10) install a better fan for the CPU
1787 11) exchange RAM chips
1788 12) exchange the motherboard.
1790 To compile this driver as a module, choose M here: the
1791 module will be called apm.
1795 config APM_IGNORE_USER_SUSPEND
1796 bool "Ignore USER SUSPEND"
1798 This option will ignore USER SUSPEND requests. On machines with a
1799 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1800 series notebooks, it is necessary to say Y because of a BIOS bug.
1802 config APM_DO_ENABLE
1803 bool "Enable PM at boot time"
1805 Enable APM features at boot time. From page 36 of the APM BIOS
1806 specification: "When disabled, the APM BIOS does not automatically
1807 power manage devices, enter the Standby State, enter the Suspend
1808 State, or take power saving steps in response to CPU Idle calls."
1809 This driver will make CPU Idle calls when Linux is idle (unless this
1810 feature is turned off -- see "Do CPU IDLE calls", below). This
1811 should always save battery power, but more complicated APM features
1812 will be dependent on your BIOS implementation. You may need to turn
1813 this option off if your computer hangs at boot time when using APM
1814 support, or if it beeps continuously instead of suspending. Turn
1815 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1816 T400CDT. This is off by default since most machines do fine without
1820 bool "Make CPU Idle calls when idle"
1822 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1823 On some machines, this can activate improved power savings, such as
1824 a slowed CPU clock rate, when the machine is idle. These idle calls
1825 are made after the idle loop has run for some length of time (e.g.,
1826 333 mS). On some machines, this will cause a hang at boot time or
1827 whenever the CPU becomes idle. (On machines with more than one CPU,
1828 this option does nothing.)
1830 config APM_DISPLAY_BLANK
1831 bool "Enable console blanking using APM"
1833 Enable console blanking using the APM. Some laptops can use this to
1834 turn off the LCD backlight when the screen blanker of the Linux
1835 virtual console blanks the screen. Note that this is only used by
1836 the virtual console screen blanker, and won't turn off the backlight
1837 when using the X Window system. This also doesn't have anything to
1838 do with your VESA-compliant power-saving monitor. Further, this
1839 option doesn't work for all laptops -- it might not turn off your
1840 backlight at all, or it might print a lot of errors to the console,
1841 especially if you are using gpm.
1843 config APM_ALLOW_INTS
1844 bool "Allow interrupts during APM BIOS calls"
1846 Normally we disable external interrupts while we are making calls to
1847 the APM BIOS as a measure to lessen the effects of a badly behaving
1848 BIOS implementation. The BIOS should reenable interrupts if it
1849 needs to. Unfortunately, some BIOSes do not -- especially those in
1850 many of the newer IBM Thinkpads. If you experience hangs when you
1851 suspend, try setting this to Y. Otherwise, say N.
1855 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1857 source "drivers/cpuidle/Kconfig"
1859 source "drivers/idle/Kconfig"
1864 menu "Bus options (PCI etc.)"
1869 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1871 Find out whether you have a PCI motherboard. PCI is the name of a
1872 bus system, i.e. the way the CPU talks to the other stuff inside
1873 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1874 VESA. If you have PCI, say Y, otherwise N.
1877 prompt "PCI access mode"
1878 depends on X86_32 && PCI
1881 On PCI systems, the BIOS can be used to detect the PCI devices and
1882 determine their configuration. However, some old PCI motherboards
1883 have BIOS bugs and may crash if this is done. Also, some embedded
1884 PCI-based systems don't have any BIOS at all. Linux can also try to
1885 detect the PCI hardware directly without using the BIOS.
1887 With this option, you can specify how Linux should detect the
1888 PCI devices. If you choose "BIOS", the BIOS will be used,
1889 if you choose "Direct", the BIOS won't be used, and if you
1890 choose "MMConfig", then PCI Express MMCONFIG will be used.
1891 If you choose "Any", the kernel will try MMCONFIG, then the
1892 direct access method and falls back to the BIOS if that doesn't
1893 work. If unsure, go with the default, which is "Any".
1898 config PCI_GOMMCONFIG
1915 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1917 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1920 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1924 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1928 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1935 bool "Support mmconfig PCI config space access"
1936 depends on X86_64 && PCI && ACPI
1938 config PCI_CNB20LE_QUIRK
1939 bool "Read CNB20LE Host Bridge Windows"
1942 Read the PCI windows out of the CNB20LE host bridge. This allows
1943 PCI hotplug to work on systems with the CNB20LE chipset which do
1947 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1948 depends on PCI_MSI && ACPI && EXPERIMENTAL
1950 DMA remapping (DMAR) devices support enables independent address
1951 translations for Direct Memory Access (DMA) from devices.
1952 These DMA remapping devices are reported via ACPI tables
1953 and include PCI device scope covered by these DMA
1956 config DMAR_DEFAULT_ON
1958 prompt "Enable DMA Remapping Devices by default"
1961 Selecting this option will enable a DMAR device at boot time if
1962 one is found. If this option is not selected, DMAR support can
1963 be enabled by passing intel_iommu=on to the kernel. It is
1964 recommended you say N here while the DMAR code remains
1967 config DMAR_BROKEN_GFX_WA
1968 bool "Workaround broken graphics drivers (going away soon)"
1969 depends on DMAR && BROKEN
1971 Current Graphics drivers tend to use physical address
1972 for DMA and avoid using DMA APIs. Setting this config
1973 option permits the IOMMU driver to set a unity map for
1974 all the OS-visible memory. Hence the driver can continue
1975 to use physical addresses for DMA, at least until this
1976 option is removed in the 2.6.32 kernel.
1978 config DMAR_FLOPPY_WA
1982 Floppy disk drivers are known to bypass DMA API calls
1983 thereby failing to work when IOMMU is enabled. This
1984 workaround will setup a 1:1 mapping for the first
1985 16MiB to make floppy (an ISA device) work.
1988 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1989 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1991 Supports Interrupt remapping for IO-APIC and MSI devices.
1992 To use x2apic mode in the CPU's which support x2APIC enhancements or
1993 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1995 source "drivers/pci/pcie/Kconfig"
1997 source "drivers/pci/Kconfig"
1999 # x86_64 have no ISA slots, but do have ISA-style DMA.
2008 Find out whether you have ISA slots on your motherboard. ISA is the
2009 name of a bus system, i.e. the way the CPU talks to the other stuff
2010 inside your box. Other bus systems are PCI, EISA, MicroChannel
2011 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2012 newer boards don't support it. If you have ISA, say Y, otherwise N.
2018 The Extended Industry Standard Architecture (EISA) bus was
2019 developed as an open alternative to the IBM MicroChannel bus.
2021 The EISA bus provided some of the features of the IBM MicroChannel
2022 bus while maintaining backward compatibility with cards made for
2023 the older ISA bus. The EISA bus saw limited use between 1988 and
2024 1995 when it was made obsolete by the PCI bus.
2026 Say Y here if you are building a kernel for an EISA-based machine.
2030 source "drivers/eisa/Kconfig"
2035 MicroChannel Architecture is found in some IBM PS/2 machines and
2036 laptops. It is a bus system similar to PCI or ISA. See
2037 <file:Documentation/mca.txt> (and especially the web page given
2038 there) before attempting to build an MCA bus kernel.
2040 source "drivers/mca/Kconfig"
2043 tristate "NatSemi SCx200 support"
2045 This provides basic support for National Semiconductor's
2046 (now AMD's) Geode processors. The driver probes for the
2047 PCI-IDs of several on-chip devices, so its a good dependency
2048 for other scx200_* drivers.
2050 If compiled as a module, the driver is named scx200.
2052 config SCx200HR_TIMER
2053 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2057 This driver provides a clocksource built upon the on-chip
2058 27MHz high-resolution timer. Its also a workaround for
2059 NSC Geode SC-1100's buggy TSC, which loses time when the
2060 processor goes idle (as is done by the scheduler). The
2061 other workaround is idle=poll boot option.
2064 bool "One Laptop Per Child support"
2067 Add support for detecting the unique features of the OLPC
2070 config OLPC_OPENFIRMWARE
2071 bool "Support for OLPC's Open Firmware"
2072 depends on !X86_64 && !X86_PAE
2075 This option adds support for the implementation of Open Firmware
2076 that is used on the OLPC XO-1 Children's Machine.
2077 If unsure, say N here.
2083 depends on CPU_SUP_AMD && PCI
2085 source "drivers/pcmcia/Kconfig"
2087 source "drivers/pci/hotplug/Kconfig"
2092 menu "Executable file formats / Emulations"
2094 source "fs/Kconfig.binfmt"
2096 config IA32_EMULATION
2097 bool "IA32 Emulation"
2099 select COMPAT_BINFMT_ELF
2101 Include code to run 32-bit programs under a 64-bit kernel. You should
2102 likely turn this on, unless you're 100% sure that you don't have any
2103 32-bit programs left.
2106 tristate "IA32 a.out support"
2107 depends on IA32_EMULATION
2109 Support old a.out binaries in the 32bit emulation.
2113 depends on IA32_EMULATION
2115 config COMPAT_FOR_U64_ALIGNMENT
2119 config SYSVIPC_COMPAT
2121 depends on COMPAT && SYSVIPC
2126 config HAVE_ATOMIC_IOMAP
2130 config HAVE_TEXT_POKE_SMP
2132 select STOP_MACHINE if SMP
2134 source "net/Kconfig"
2136 source "drivers/Kconfig"
2138 source "drivers/firmware/Kconfig"
2142 source "arch/x86/Kconfig.debug"
2144 source "security/Kconfig"
2146 source "crypto/Kconfig"
2148 source "arch/x86/kvm/Kconfig"
2150 source "lib/Kconfig"