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
63 config INSTRUCTION_DECODER
64 def_bool (KPROBES || PERF_EVENTS)
68 default "elf32-i386" if X86_32
69 default "elf64-x86-64" if X86_64
73 default "arch/x86/configs/i386_defconfig" if X86_32
74 default "arch/x86/configs/x86_64_defconfig" if X86_64
79 config GENERIC_CMOS_UPDATE
82 config CLOCKSOURCE_WATCHDOG
85 config GENERIC_CLOCKEVENTS
88 config GENERIC_CLOCKEVENTS_BROADCAST
90 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
92 config LOCKDEP_SUPPORT
95 config STACKTRACE_SUPPORT
98 config HAVE_LATENCYTOP_SUPPORT
110 config NEED_DMA_MAP_STATE
111 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
113 config NEED_SG_DMA_LENGTH
116 config GENERIC_ISA_DMA
125 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
127 config GENERIC_BUG_RELATIVE_POINTERS
130 config GENERIC_HWEIGHT
136 config ARCH_MAY_HAVE_PC_FDC
139 config RWSEM_GENERIC_SPINLOCK
142 config RWSEM_XCHGADD_ALGORITHM
145 config ARCH_HAS_CPU_IDLE_WAIT
148 config GENERIC_CALIBRATE_DELAY
151 config GENERIC_TIME_VSYSCALL
155 config ARCH_HAS_CPU_RELAX
158 config ARCH_HAS_DEFAULT_IDLE
161 config ARCH_HAS_CACHE_LINE_SIZE
164 config HAVE_SETUP_PER_CPU_AREA
167 config NEED_PER_CPU_EMBED_FIRST_CHUNK
170 config NEED_PER_CPU_PAGE_FIRST_CHUNK
173 config HAVE_CPUMASK_OF_CPU_MAP
176 config ARCH_HIBERNATION_POSSIBLE
179 config ARCH_SUSPEND_POSSIBLE
186 config ARCH_POPULATES_NODE_MAP
193 config ARCH_SUPPORTS_OPTIMIZED_INLINING
196 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
199 config HAVE_EARLY_RES
202 config HAVE_INTEL_TXT
204 depends on EXPERIMENTAL && DMAR && ACPI
206 # Use the generic interrupt handling code in kernel/irq/:
207 config GENERIC_HARDIRQS
210 config GENERIC_HARDIRQS_NO__DO_IRQ
213 config GENERIC_IRQ_PROBE
216 config GENERIC_PENDING_IRQ
218 depends on GENERIC_HARDIRQS && SMP
220 config USE_GENERIC_SMP_HELPERS
226 depends on X86_32 && SMP
230 depends on X86_64 && SMP
236 config X86_TRAMPOLINE
238 depends on SMP || (64BIT && ACPI_SLEEP)
240 config X86_32_LAZY_GS
242 depends on X86_32 && !CC_STACKPROTECTOR
244 config ARCH_HWEIGHT_CFLAGS
246 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
247 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 source "init/Kconfig"
252 source "kernel/Kconfig.freezer"
254 menu "Processor type and features"
256 source "kernel/time/Kconfig"
259 bool "Symmetric multi-processing support"
261 This enables support for systems with more than one CPU. If you have
262 a system with only one CPU, like most personal computers, say N. If
263 you have a system with more than one CPU, say Y.
265 If you say N here, the kernel will run on single and multiprocessor
266 machines, but will use only one CPU of a multiprocessor machine. If
267 you say Y here, the kernel will run on many, but not all,
268 singleprocessor machines. On a singleprocessor machine, the kernel
269 will run faster if you say N here.
271 Note that if you say Y here and choose architecture "586" or
272 "Pentium" under "Processor family", the kernel will not work on 486
273 architectures. Similarly, multiprocessor kernels for the "PPro"
274 architecture may not work on all Pentium based boards.
276 People using multiprocessor machines who say Y here should also say
277 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
278 Management" code will be disabled if you say Y here.
280 See also <file:Documentation/i386/IO-APIC.txt>,
281 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
282 <http://www.tldp.org/docs.html#howto>.
284 If you don't know what to do here, say N.
287 bool "Support x2apic"
288 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
290 This enables x2apic support on CPUs that have this feature.
292 This allows 32-bit apic IDs (so it can support very large systems),
293 and accesses the local apic via MSRs not via mmio.
295 If you don't know what to do here, say N.
298 bool "Support sparse irq numbering"
299 depends on PCI_MSI || HT_IRQ
301 This enables support for sparse irqs. This is useful for distro
302 kernels that want to define a high CONFIG_NR_CPUS value but still
303 want to have low kernel memory footprint on smaller machines.
305 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
306 out the irq_desc[] array in a more NUMA-friendly way. )
308 If you don't know what to do here, say N.
312 depends on SPARSE_IRQ && NUMA
315 bool "Enable MPS table" if ACPI
317 depends on X86_LOCAL_APIC
319 For old smp systems that do not have proper acpi support. Newer systems
320 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
323 bool "Support for big SMP systems with more than 8 CPUs"
324 depends on X86_32 && SMP
326 This option is needed for the systems that have more than 8 CPUs
329 config X86_EXTENDED_PLATFORM
330 bool "Support for extended (non-PC) x86 platforms"
333 If you disable this option then the kernel will only support
334 standard PC platforms. (which covers the vast majority of
337 If you enable this option then you'll be able to select support
338 for the following (non-PC) 32 bit x86 platforms:
342 SGI 320/540 (Visual Workstation)
343 Summit/EXA (IBM x440)
344 Unisys ES7000 IA32 series
345 Moorestown MID devices
347 If you have one of these systems, or if you want to build a
348 generic distribution kernel, say Y here - otherwise say N.
352 config X86_EXTENDED_PLATFORM
353 bool "Support for extended (non-PC) x86 platforms"
356 If you disable this option then the kernel will only support
357 standard PC platforms. (which covers the vast majority of
360 If you enable this option then you'll be able to select support
361 for the following (non-PC) 64 bit x86 platforms:
365 If you have one of these systems, or if you want to build a
366 generic distribution kernel, say Y here - otherwise say N.
368 # This is an alphabetically sorted list of 64 bit extended platforms
369 # Please maintain the alphabetic order if and when there are additions
374 depends on X86_64 && PCI
375 depends on X86_EXTENDED_PLATFORM
377 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
378 supposed to run on these EM64T-based machines. Only choose this option
379 if you have one of these machines.
382 bool "SGI Ultraviolet"
384 depends on X86_EXTENDED_PLATFORM
386 depends on X86_X2APIC
388 This option is needed in order to support SGI Ultraviolet systems.
389 If you don't have one of these, you should say N here.
391 # Following is an alphabetically sorted list of 32 bit extended platforms
392 # Please maintain the alphabetic order if and when there are additions
397 depends on X86_EXTENDED_PLATFORM
399 Select this for an AMD Elan processor.
401 Do not use this option for K6/Athlon/Opteron processors!
403 If unsure, choose "PC-compatible" instead.
406 bool "Moorestown MID platform"
410 depends on X86_EXTENDED_PLATFORM
411 depends on X86_IO_APIC
414 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
415 Internet Device(MID) platform. Moorestown consists of two chips:
416 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
417 Unlike standard x86 PCs, Moorestown does not have many legacy devices
418 nor standard legacy replacement devices/features. e.g. Moorestown does
419 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
422 bool "RDC R-321x SoC"
424 depends on X86_EXTENDED_PLATFORM
426 select X86_REBOOTFIXUPS
428 This option is needed for RDC R-321x system-on-chip, also known
430 If you don't have one of these chips, you should say N here.
432 config X86_32_NON_STANDARD
433 bool "Support non-standard 32-bit SMP architectures"
434 depends on X86_32 && SMP
435 depends on X86_EXTENDED_PLATFORM
437 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
438 subarchitectures. It is intended for a generic binary kernel.
439 if you select them all, kernel will probe it one by one. and will
442 # Alphabetically sorted list of Non standard 32 bit platforms
445 bool "NUMAQ (IBM/Sequent)"
446 depends on X86_32_NON_STANDARD
451 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
452 NUMA multiquad box. This changes the way that processors are
453 bootstrapped, and uses Clustered Logical APIC addressing mode instead
454 of Flat Logical. You will need a new lynxer.elf file to flash your
455 firmware with - send email to <Martin.Bligh@us.ibm.com>.
457 config X86_SUPPORTS_MEMORY_FAILURE
459 # MCE code calls memory_failure():
461 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
462 depends on !X86_NUMAQ
463 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
464 depends on X86_64 || !SPARSEMEM
465 select ARCH_SUPPORTS_MEMORY_FAILURE
468 bool "SGI 320/540 (Visual Workstation)"
469 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
470 depends on X86_32_NON_STANDARD
472 The SGI Visual Workstation series is an IA32-based workstation
473 based on SGI systems chips with some legacy PC hardware attached.
475 Say Y here to create a kernel to run on the SGI 320 or 540.
477 A kernel compiled for the Visual Workstation will run on general
478 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
481 bool "Summit/EXA (IBM x440)"
482 depends on X86_32_NON_STANDARD
484 This option is needed for IBM systems that use the Summit/EXA chipset.
485 In particular, it is needed for the x440.
488 bool "Unisys ES7000 IA32 series"
489 depends on X86_32_NON_STANDARD && X86_BIGSMP
491 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
492 supposed to run on an IA32-based Unisys ES7000 system.
494 config SCHED_OMIT_FRAME_POINTER
496 prompt "Single-depth WCHAN output"
499 Calculate simpler /proc/<PID>/wchan values. If this option
500 is disabled then wchan values will recurse back to the
501 caller function. This provides more accurate wchan values,
502 at the expense of slightly more scheduling overhead.
504 If in doubt, say "Y".
506 menuconfig PARAVIRT_GUEST
507 bool "Paravirtualized guest support"
509 Say Y here to get to see options related to running Linux under
510 various hypervisors. This option alone does not add any kernel code.
512 If you say N, all options in this submenu will be skipped and disabled.
516 source "arch/x86/xen/Kconfig"
519 bool "VMI Guest support (DEPRECATED)"
523 VMI provides a paravirtualized interface to the VMware ESX server
524 (it could be used by other hypervisors in theory too, but is not
525 at the moment), by linking the kernel to a GPL-ed ROM module
526 provided by the hypervisor.
528 As of September 2009, VMware has started a phased retirement
529 of this feature from VMware's products. Please see
530 feature-removal-schedule.txt for details. If you are
531 planning to enable this option, please note that you cannot
532 live migrate a VMI enabled VM to a future VMware product,
533 which doesn't support VMI. So if you expect your kernel to
534 seamlessly migrate to newer VMware products, keep this
538 bool "KVM paravirtualized clock"
540 select PARAVIRT_CLOCK
542 Turning on this option will allow you to run a paravirtualized clock
543 when running over the KVM hypervisor. Instead of relying on a PIT
544 (or probably other) emulation by the underlying device model, the host
545 provides the guest with timing infrastructure such as time of day, and
549 bool "KVM Guest support"
552 This option enables various optimizations for running under the KVM
555 source "arch/x86/lguest/Kconfig"
558 bool "Enable paravirtualization code"
560 This changes the kernel so it can modify itself when it is run
561 under a hypervisor, potentially improving performance significantly
562 over full virtualization. However, when run without a hypervisor
563 the kernel is theoretically slower and slightly larger.
565 config PARAVIRT_SPINLOCKS
566 bool "Paravirtualization layer for spinlocks"
567 depends on PARAVIRT && SMP && EXPERIMENTAL
569 Paravirtualized spinlocks allow a pvops backend to replace the
570 spinlock implementation with something virtualization-friendly
571 (for example, block the virtual CPU rather than spinning).
573 Unfortunately the downside is an up to 5% performance hit on
574 native kernels, with various workloads.
576 If you are unsure how to answer this question, answer N.
578 config PARAVIRT_CLOCK
583 config PARAVIRT_DEBUG
584 bool "paravirt-ops debugging"
585 depends on PARAVIRT && DEBUG_KERNEL
587 Enable to debug paravirt_ops internals. Specifically, BUG if
588 a paravirt_op is missing when it is called.
592 bool "Disable Bootmem code"
594 Use early_res directly instead of bootmem before slab is ready.
595 - allocator (buddy) [generic]
596 - early allocator (bootmem) [generic]
597 - very early allocator (reserve_early*()) [x86]
598 - very very early allocator (early brk model) [x86]
599 So reduce one layer between early allocator to final allocator
605 This option adds a kernel parameter 'memtest', which allows memtest
607 memtest=0, mean disabled; -- default
608 memtest=1, mean do 1 test pattern;
610 memtest=4, mean do 4 test patterns.
611 If you are unsure how to answer this question, answer N.
613 config X86_SUMMIT_NUMA
615 depends on X86_32 && NUMA && X86_32_NON_STANDARD
617 config X86_CYCLONE_TIMER
619 depends on X86_32_NON_STANDARD
621 source "arch/x86/Kconfig.cpu"
625 prompt "HPET Timer Support" if X86_32
627 Use the IA-PC HPET (High Precision Event Timer) to manage
628 time in preference to the PIT and RTC, if a HPET is
630 HPET is the next generation timer replacing legacy 8254s.
631 The HPET provides a stable time base on SMP
632 systems, unlike the TSC, but it is more expensive to access,
633 as it is off-chip. You can find the HPET spec at
634 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
636 You can safely choose Y here. However, HPET will only be
637 activated if the platform and the BIOS support this feature.
638 Otherwise the 8254 will be used for timing services.
640 Choose N to continue using the legacy 8254 timer.
642 config HPET_EMULATE_RTC
644 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
648 prompt "Langwell APB Timer Support" if X86_MRST
650 APB timer is the replacement for 8254, HPET on X86 MID platforms.
651 The APBT provides a stable time base on SMP
652 systems, unlike the TSC, but it is more expensive to access,
653 as it is off-chip. APB timers are always running regardless of CPU
654 C states, they are used as per CPU clockevent device when possible.
656 # Mark as embedded because too many people got it wrong.
657 # The code disables itself when not needed.
660 bool "Enable DMI scanning" if EMBEDDED
662 Enabled scanning of DMI to identify machine quirks. Say Y
663 here unless you have verified that your setup is not
664 affected by entries in the DMI blacklist. Required by PNP
668 bool "GART IOMMU support" if EMBEDDED
671 depends on X86_64 && PCI && K8_NB
673 Support for full DMA access of devices with 32bit memory access only
674 on systems with more than 3GB. This is usually needed for USB,
675 sound, many IDE/SATA chipsets and some other devices.
676 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
677 based hardware IOMMU and a software bounce buffer based IOMMU used
678 on Intel systems and as fallback.
679 The code is only active when needed (enough memory and limited
680 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
684 bool "IBM Calgary IOMMU support"
686 depends on X86_64 && PCI && EXPERIMENTAL
688 Support for hardware IOMMUs in IBM's xSeries x366 and x460
689 systems. Needed to run systems with more than 3GB of memory
690 properly with 32-bit PCI devices that do not support DAC
691 (Double Address Cycle). Calgary also supports bus level
692 isolation, where all DMAs pass through the IOMMU. This
693 prevents them from going anywhere except their intended
694 destination. This catches hard-to-find kernel bugs and
695 mis-behaving drivers and devices that do not use the DMA-API
696 properly to set up their DMA buffers. The IOMMU can be
697 turned off at boot time with the iommu=off parameter.
698 Normally the kernel will make the right choice by itself.
701 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
703 prompt "Should Calgary be enabled by default?"
704 depends on CALGARY_IOMMU
706 Should Calgary be enabled by default? if you choose 'y', Calgary
707 will be used (if it exists). If you choose 'n', Calgary will not be
708 used even if it exists. If you choose 'n' and would like to use
709 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
713 bool "AMD IOMMU support"
716 depends on X86_64 && PCI && ACPI
718 With this option you can enable support for AMD IOMMU hardware in
719 your system. An IOMMU is a hardware component which provides
720 remapping of DMA memory accesses from devices. With an AMD IOMMU you
721 can isolate the the DMA memory of different devices and protect the
722 system from misbehaving device drivers or hardware.
724 You can find out if your system has an AMD IOMMU if you look into
725 your BIOS for an option to enable it or if you have an IVRS ACPI
728 config AMD_IOMMU_STATS
729 bool "Export AMD IOMMU statistics to debugfs"
733 This option enables code in the AMD IOMMU driver to collect various
734 statistics about whats happening in the driver and exports that
735 information to userspace via debugfs.
738 # need this always selected by IOMMU for the VIA workaround
742 Support for software bounce buffers used on x86-64 systems
743 which don't have a hardware IOMMU (e.g. the current generation
744 of Intel's x86-64 CPUs). Using this PCI devices which can only
745 access 32-bits of memory can be used on systems with more than
746 3 GB of memory. If unsure, say Y.
749 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
752 def_bool (AMD_IOMMU || DMAR)
755 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
756 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
757 select CPUMASK_OFFSTACK
759 Configure maximum number of CPUS and NUMA Nodes for this architecture.
763 int "Maximum number of CPUs" if SMP && !MAXSMP
764 range 2 8 if SMP && X86_32 && !X86_BIGSMP
765 range 2 512 if SMP && !MAXSMP
767 default "4096" if MAXSMP
768 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
771 This allows you to specify the maximum number of CPUs which this
772 kernel will support. The maximum supported value is 512 and the
773 minimum value which makes sense is 2.
775 This is purely to save memory - each supported CPU adds
776 approximately eight kilobytes to the kernel image.
779 bool "SMT (Hyperthreading) scheduler support"
782 SMT scheduler support improves the CPU scheduler's decision making
783 when dealing with Intel Pentium 4 chips with HyperThreading at a
784 cost of slightly increased overhead in some places. If unsure say
789 prompt "Multi-core scheduler support"
792 Multi-core scheduler support improves the CPU scheduler's decision
793 making when dealing with multi-core CPU chips at a cost of slightly
794 increased overhead in some places. If unsure say N here.
796 source "kernel/Kconfig.preempt"
799 bool "Local APIC support on uniprocessors"
800 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
802 A local APIC (Advanced Programmable Interrupt Controller) is an
803 integrated interrupt controller in the CPU. If you have a single-CPU
804 system which has a processor with a local APIC, you can say Y here to
805 enable and use it. If you say Y here even though your machine doesn't
806 have a local APIC, then the kernel will still run with no slowdown at
807 all. The local APIC supports CPU-generated self-interrupts (timer,
808 performance counters), and the NMI watchdog which detects hard
812 bool "IO-APIC support on uniprocessors"
813 depends on X86_UP_APIC
815 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
816 SMP-capable replacement for PC-style interrupt controllers. Most
817 SMP systems and many recent uniprocessor systems have one.
819 If you have a single-CPU system with an IO-APIC, you can say Y here
820 to use it. If you say Y here even though your machine doesn't have
821 an IO-APIC, then the kernel will still run with no slowdown at all.
823 config X86_LOCAL_APIC
825 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
829 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
831 config X86_VISWS_APIC
833 depends on X86_32 && X86_VISWS
835 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
836 bool "Reroute for broken boot IRQs"
837 depends on X86_IO_APIC
839 This option enables a workaround that fixes a source of
840 spurious interrupts. This is recommended when threaded
841 interrupt handling is used on systems where the generation of
842 superfluous "boot interrupts" cannot be disabled.
844 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
845 entry in the chipset's IO-APIC is masked (as, e.g. the RT
846 kernel does during interrupt handling). On chipsets where this
847 boot IRQ generation cannot be disabled, this workaround keeps
848 the original IRQ line masked so that only the equivalent "boot
849 IRQ" is delivered to the CPUs. The workaround also tells the
850 kernel to set up the IRQ handler on the boot IRQ line. In this
851 way only one interrupt is delivered to the kernel. Otherwise
852 the spurious second interrupt may cause the kernel to bring
853 down (vital) interrupt lines.
855 Only affects "broken" chipsets. Interrupt sharing may be
856 increased on these systems.
859 bool "Machine Check / overheating reporting"
861 Machine Check support allows the processor to notify the
862 kernel if it detects a problem (e.g. overheating, data corruption).
863 The action the kernel takes depends on the severity of the problem,
864 ranging from warning messages to halting the machine.
868 prompt "Intel MCE features"
869 depends on X86_MCE && X86_LOCAL_APIC
871 Additional support for intel specific MCE features such as
876 prompt "AMD MCE features"
877 depends on X86_MCE && X86_LOCAL_APIC
879 Additional support for AMD specific MCE features such as
880 the DRAM Error Threshold.
882 config X86_ANCIENT_MCE
883 bool "Support for old Pentium 5 / WinChip machine checks"
884 depends on X86_32 && X86_MCE
886 Include support for machine check handling on old Pentium 5 or WinChip
887 systems. These typically need to be enabled explicitely on the command
890 config X86_MCE_THRESHOLD
891 depends on X86_MCE_AMD || X86_MCE_INTEL
894 config X86_MCE_INJECT
896 tristate "Machine check injector support"
898 Provide support for injecting machine checks for testing purposes.
899 If you don't know what a machine check is and you don't do kernel
900 QA it is safe to say n.
902 config X86_THERMAL_VECTOR
904 depends on X86_MCE_INTEL
907 bool "Enable VM86 support" if EMBEDDED
911 This option is required by programs like DOSEMU to run 16-bit legacy
912 code on X86 processors. It also may be needed by software like
913 XFree86 to initialize some video cards via BIOS. Disabling this
914 option saves about 6k.
917 tristate "Toshiba Laptop support"
920 This adds a driver to safely access the System Management Mode of
921 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
922 not work on models with a Phoenix BIOS. The System Management Mode
923 is used to set the BIOS and power saving options on Toshiba portables.
925 For information on utilities to make use of this driver see the
926 Toshiba Linux utilities web site at:
927 <http://www.buzzard.org.uk/toshiba/>.
929 Say Y if you intend to run this kernel on a Toshiba portable.
933 tristate "Dell laptop support"
935 This adds a driver to safely access the System Management Mode
936 of the CPU on the Dell Inspiron 8000. The System Management Mode
937 is used to read cpu temperature and cooling fan status and to
938 control the fans on the I8K portables.
940 This driver has been tested only on the Inspiron 8000 but it may
941 also work with other Dell laptops. You can force loading on other
942 models by passing the parameter `force=1' to the module. Use at
945 For information on utilities to make use of this driver see the
946 I8K Linux utilities web site at:
947 <http://people.debian.org/~dz/i8k/>
949 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
952 config X86_REBOOTFIXUPS
953 bool "Enable X86 board specific fixups for reboot"
956 This enables chipset and/or board specific fixups to be done
957 in order to get reboot to work correctly. This is only needed on
958 some combinations of hardware and BIOS. The symptom, for which
959 this config is intended, is when reboot ends with a stalled/hung
962 Currently, the only fixup is for the Geode machines using
963 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
965 Say Y if you want to enable the fixup. Currently, it's safe to
966 enable this option even if you don't need it.
970 tristate "/dev/cpu/microcode - microcode support"
973 If you say Y here, you will be able to update the microcode on
974 certain Intel and AMD processors. The Intel support is for the
975 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
976 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
977 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
978 You will obviously need the actual microcode binary data itself
979 which is not shipped with the Linux kernel.
981 This option selects the general module only, you need to select
982 at least one vendor specific module as well.
984 To compile this driver as a module, choose M here: the
985 module will be called microcode.
987 config MICROCODE_INTEL
988 bool "Intel microcode patch loading support"
993 This options enables microcode patch loading support for Intel
996 For latest news and information on obtaining all the required
997 Intel ingredients for this driver, check:
998 <http://www.urbanmyth.org/microcode/>.
1000 config MICROCODE_AMD
1001 bool "AMD microcode patch loading support"
1002 depends on MICROCODE
1005 If you select this option, microcode patch loading support for AMD
1006 processors will be enabled.
1008 config MICROCODE_OLD_INTERFACE
1010 depends on MICROCODE
1013 tristate "/dev/cpu/*/msr - Model-specific register support"
1015 This device gives privileged processes access to the x86
1016 Model-Specific Registers (MSRs). It is a character device with
1017 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1018 MSR accesses are directed to a specific CPU on multi-processor
1022 tristate "/dev/cpu/*/cpuid - CPU information support"
1024 This device gives processes access to the x86 CPUID instruction to
1025 be executed on a specific processor. It is a character device
1026 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1030 prompt "High Memory Support"
1031 default HIGHMEM64G if X86_NUMAQ
1037 depends on !X86_NUMAQ
1039 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1040 However, the address space of 32-bit x86 processors is only 4
1041 Gigabytes large. That means that, if you have a large amount of
1042 physical memory, not all of it can be "permanently mapped" by the
1043 kernel. The physical memory that's not permanently mapped is called
1046 If you are compiling a kernel which will never run on a machine with
1047 more than 1 Gigabyte total physical RAM, answer "off" here (default
1048 choice and suitable for most users). This will result in a "3GB/1GB"
1049 split: 3GB are mapped so that each process sees a 3GB virtual memory
1050 space and the remaining part of the 4GB virtual memory space is used
1051 by the kernel to permanently map as much physical memory as
1054 If the machine has between 1 and 4 Gigabytes physical RAM, then
1057 If more than 4 Gigabytes is used then answer "64GB" here. This
1058 selection turns Intel PAE (Physical Address Extension) mode on.
1059 PAE implements 3-level paging on IA32 processors. PAE is fully
1060 supported by Linux, PAE mode is implemented on all recent Intel
1061 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1062 then the kernel will not boot on CPUs that don't support PAE!
1064 The actual amount of total physical memory will either be
1065 auto detected or can be forced by using a kernel command line option
1066 such as "mem=256M". (Try "man bootparam" or see the documentation of
1067 your boot loader (lilo or loadlin) about how to pass options to the
1068 kernel at boot time.)
1070 If unsure, say "off".
1074 depends on !X86_NUMAQ
1076 Select this if you have a 32-bit processor and between 1 and 4
1077 gigabytes of physical RAM.
1081 depends on !M386 && !M486
1084 Select this if you have a 32-bit processor and more than 4
1085 gigabytes of physical RAM.
1090 depends on EXPERIMENTAL
1091 prompt "Memory split" if EMBEDDED
1095 Select the desired split between kernel and user memory.
1097 If the address range available to the kernel is less than the
1098 physical memory installed, the remaining memory will be available
1099 as "high memory". Accessing high memory is a little more costly
1100 than low memory, as it needs to be mapped into the kernel first.
1101 Note that increasing the kernel address space limits the range
1102 available to user programs, making the address space there
1103 tighter. Selecting anything other than the default 3G/1G split
1104 will also likely make your kernel incompatible with binary-only
1107 If you are not absolutely sure what you are doing, leave this
1111 bool "3G/1G user/kernel split"
1112 config VMSPLIT_3G_OPT
1114 bool "3G/1G user/kernel split (for full 1G low memory)"
1116 bool "2G/2G user/kernel split"
1117 config VMSPLIT_2G_OPT
1119 bool "2G/2G user/kernel split (for full 2G low memory)"
1121 bool "1G/3G user/kernel split"
1126 default 0xB0000000 if VMSPLIT_3G_OPT
1127 default 0x80000000 if VMSPLIT_2G
1128 default 0x78000000 if VMSPLIT_2G_OPT
1129 default 0x40000000 if VMSPLIT_1G
1135 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1138 bool "PAE (Physical Address Extension) Support"
1139 depends on X86_32 && !HIGHMEM4G
1141 PAE is required for NX support, and furthermore enables
1142 larger swapspace support for non-overcommit purposes. It
1143 has the cost of more pagetable lookup overhead, and also
1144 consumes more pagetable space per process.
1146 config ARCH_PHYS_ADDR_T_64BIT
1147 def_bool X86_64 || X86_PAE
1149 config DIRECT_GBPAGES
1150 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1154 Allow the kernel linear mapping to use 1GB pages on CPUs that
1155 support it. This can improve the kernel's performance a tiny bit by
1156 reducing TLB pressure. If in doubt, say "Y".
1158 # Common NUMA Features
1160 bool "Numa Memory Allocation and Scheduler Support"
1162 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1163 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1165 Enable NUMA (Non Uniform Memory Access) support.
1167 The kernel will try to allocate memory used by a CPU on the
1168 local memory controller of the CPU and add some more
1169 NUMA awareness to the kernel.
1171 For 64-bit this is recommended if the system is Intel Core i7
1172 (or later), AMD Opteron, or EM64T NUMA.
1174 For 32-bit this is only needed on (rare) 32-bit-only platforms
1175 that support NUMA topologies, such as NUMAQ / Summit, or if you
1176 boot a 32-bit kernel on a 64-bit NUMA platform.
1178 Otherwise, you should say N.
1180 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1181 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1185 prompt "Old style AMD Opteron NUMA detection"
1186 depends on X86_64 && NUMA && PCI
1188 Enable K8 NUMA node topology detection. You should say Y here if
1189 you have a multi processor AMD K8 system. This uses an old
1190 method to read the NUMA configuration directly from the builtin
1191 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1192 instead, which also takes priority if both are compiled in.
1194 config X86_64_ACPI_NUMA
1196 prompt "ACPI NUMA detection"
1197 depends on X86_64 && NUMA && ACPI && PCI
1200 Enable ACPI SRAT based node topology detection.
1202 # Some NUMA nodes have memory ranges that span
1203 # other nodes. Even though a pfn is valid and
1204 # between a node's start and end pfns, it may not
1205 # reside on that node. See memmap_init_zone()
1207 config NODES_SPAN_OTHER_NODES
1209 depends on X86_64_ACPI_NUMA
1212 bool "NUMA emulation"
1213 depends on X86_64 && NUMA
1215 Enable NUMA emulation. A flat machine will be split
1216 into virtual nodes when booted with "numa=fake=N", where N is the
1217 number of nodes. This is only useful for debugging.
1220 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1222 default "10" if MAXSMP
1223 default "6" if X86_64
1224 default "4" if X86_NUMAQ
1226 depends on NEED_MULTIPLE_NODES
1228 Specify the maximum number of NUMA Nodes available on the target
1229 system. Increases memory reserved to accommodate various tables.
1231 config HAVE_ARCH_BOOTMEM
1233 depends on X86_32 && NUMA
1235 config ARCH_HAVE_MEMORY_PRESENT
1237 depends on X86_32 && DISCONTIGMEM
1239 config NEED_NODE_MEMMAP_SIZE
1241 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1243 config HAVE_ARCH_ALLOC_REMAP
1245 depends on X86_32 && NUMA
1247 config ARCH_FLATMEM_ENABLE
1249 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1251 config ARCH_DISCONTIGMEM_ENABLE
1253 depends on NUMA && X86_32
1255 config ARCH_DISCONTIGMEM_DEFAULT
1257 depends on NUMA && X86_32
1259 config ARCH_PROC_KCORE_TEXT
1261 depends on X86_64 && PROC_KCORE
1263 config ARCH_SPARSEMEM_DEFAULT
1267 config ARCH_SPARSEMEM_ENABLE
1269 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1270 select SPARSEMEM_STATIC if X86_32
1271 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1273 config ARCH_SELECT_MEMORY_MODEL
1275 depends on ARCH_SPARSEMEM_ENABLE
1277 config ARCH_MEMORY_PROBE
1279 depends on MEMORY_HOTPLUG
1281 config ILLEGAL_POINTER_VALUE
1284 default 0xdead000000000000 if X86_64
1289 bool "Allocate 3rd-level pagetables from highmem"
1292 The VM uses one page table entry for each page of physical memory.
1293 For systems with a lot of RAM, this can be wasteful of precious
1294 low memory. Setting this option will put user-space page table
1295 entries in high memory.
1297 config X86_CHECK_BIOS_CORRUPTION
1298 bool "Check for low memory corruption"
1300 Periodically check for memory corruption in low memory, which
1301 is suspected to be caused by BIOS. Even when enabled in the
1302 configuration, it is disabled at runtime. Enable it by
1303 setting "memory_corruption_check=1" on the kernel command
1304 line. By default it scans the low 64k of memory every 60
1305 seconds; see the memory_corruption_check_size and
1306 memory_corruption_check_period parameters in
1307 Documentation/kernel-parameters.txt to adjust this.
1309 When enabled with the default parameters, this option has
1310 almost no overhead, as it reserves a relatively small amount
1311 of memory and scans it infrequently. It both detects corruption
1312 and prevents it from affecting the running system.
1314 It is, however, intended as a diagnostic tool; if repeatable
1315 BIOS-originated corruption always affects the same memory,
1316 you can use memmap= to prevent the kernel from using that
1319 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1320 bool "Set the default setting of memory_corruption_check"
1321 depends on X86_CHECK_BIOS_CORRUPTION
1324 Set whether the default state of memory_corruption_check is
1327 config X86_RESERVE_LOW_64K
1328 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1331 Reserve the first 64K of physical RAM on BIOSes that are known
1332 to potentially corrupt that memory range. A numbers of BIOSes are
1333 known to utilize this area during suspend/resume, so it must not
1334 be used by the kernel.
1336 Set this to N if you are absolutely sure that you trust the BIOS
1337 to get all its memory reservations and usages right.
1339 If you have doubts about the BIOS (e.g. suspend/resume does not
1340 work or there's kernel crashes after certain hardware hotplug
1341 events) and it's not AMI or Phoenix, then you might want to enable
1342 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1343 corruption patterns.
1347 config MATH_EMULATION
1349 prompt "Math emulation" if X86_32
1351 Linux can emulate a math coprocessor (used for floating point
1352 operations) if you don't have one. 486DX and Pentium processors have
1353 a math coprocessor built in, 486SX and 386 do not, unless you added
1354 a 487DX or 387, respectively. (The messages during boot time can
1355 give you some hints here ["man dmesg"].) Everyone needs either a
1356 coprocessor or this emulation.
1358 If you don't have a math coprocessor, you need to say Y here; if you
1359 say Y here even though you have a coprocessor, the coprocessor will
1360 be used nevertheless. (This behavior can be changed with the kernel
1361 command line option "no387", which comes handy if your coprocessor
1362 is broken. Try "man bootparam" or see the documentation of your boot
1363 loader (lilo or loadlin) about how to pass options to the kernel at
1364 boot time.) This means that it is a good idea to say Y here if you
1365 intend to use this kernel on different machines.
1367 More information about the internals of the Linux math coprocessor
1368 emulation can be found in <file:arch/x86/math-emu/README>.
1370 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1371 kernel, it won't hurt.
1375 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1377 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1378 the Memory Type Range Registers (MTRRs) may be used to control
1379 processor access to memory ranges. This is most useful if you have
1380 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1381 allows bus write transfers to be combined into a larger transfer
1382 before bursting over the PCI/AGP bus. This can increase performance
1383 of image write operations 2.5 times or more. Saying Y here creates a
1384 /proc/mtrr file which may be used to manipulate your processor's
1385 MTRRs. Typically the X server should use this.
1387 This code has a reasonably generic interface so that similar
1388 control registers on other processors can be easily supported
1391 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1392 Registers (ARRs) which provide a similar functionality to MTRRs. For
1393 these, the ARRs are used to emulate the MTRRs.
1394 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1395 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1396 write-combining. All of these processors are supported by this code
1397 and it makes sense to say Y here if you have one of them.
1399 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1400 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1401 can lead to all sorts of problems, so it's good to say Y here.
1403 You can safely say Y even if your machine doesn't have MTRRs, you'll
1404 just add about 9 KB to your kernel.
1406 See <file:Documentation/x86/mtrr.txt> for more information.
1408 config MTRR_SANITIZER
1410 prompt "MTRR cleanup support"
1413 Convert MTRR layout from continuous to discrete, so X drivers can
1414 add writeback entries.
1416 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1417 The largest mtrr entry size for a continuous block can be set with
1422 config MTRR_SANITIZER_ENABLE_DEFAULT
1423 int "MTRR cleanup enable value (0-1)"
1426 depends on MTRR_SANITIZER
1428 Enable mtrr cleanup default value
1430 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1431 int "MTRR cleanup spare reg num (0-7)"
1434 depends on MTRR_SANITIZER
1436 mtrr cleanup spare entries default, it can be changed via
1437 mtrr_spare_reg_nr=N on the kernel command line.
1441 prompt "x86 PAT support" if EMBEDDED
1444 Use PAT attributes to setup page level cache control.
1446 PATs are the modern equivalents of MTRRs and are much more
1447 flexible than MTRRs.
1449 Say N here if you see bootup problems (boot crash, boot hang,
1450 spontaneous reboots) or a non-working video driver.
1454 config ARCH_USES_PG_UNCACHED
1459 bool "EFI runtime service support"
1462 This enables the kernel to use EFI runtime services that are
1463 available (such as the EFI variable services).
1465 This option is only useful on systems that have EFI firmware.
1466 In addition, you should use the latest ELILO loader available
1467 at <http://elilo.sourceforge.net> in order to take advantage
1468 of EFI runtime services. However, even with this option, the
1469 resultant kernel should continue to boot on existing non-EFI
1474 prompt "Enable seccomp to safely compute untrusted bytecode"
1476 This kernel feature is useful for number crunching applications
1477 that may need to compute untrusted bytecode during their
1478 execution. By using pipes or other transports made available to
1479 the process as file descriptors supporting the read/write
1480 syscalls, it's possible to isolate those applications in
1481 their own address space using seccomp. Once seccomp is
1482 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1483 and the task is only allowed to execute a few safe syscalls
1484 defined by each seccomp mode.
1486 If unsure, say Y. Only embedded should say N here.
1488 config CC_STACKPROTECTOR
1489 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1491 This option turns on the -fstack-protector GCC feature. This
1492 feature puts, at the beginning of functions, a canary value on
1493 the stack just before the return address, and validates
1494 the value just before actually returning. Stack based buffer
1495 overflows (that need to overwrite this return address) now also
1496 overwrite the canary, which gets detected and the attack is then
1497 neutralized via a kernel panic.
1499 This feature requires gcc version 4.2 or above, or a distribution
1500 gcc with the feature backported. Older versions are automatically
1501 detected and for those versions, this configuration option is
1502 ignored. (and a warning is printed during bootup)
1504 source kernel/Kconfig.hz
1507 bool "kexec system call"
1509 kexec is a system call that implements the ability to shutdown your
1510 current kernel, and to start another kernel. It is like a reboot
1511 but it is independent of the system firmware. And like a reboot
1512 you can start any kernel with it, not just Linux.
1514 The name comes from the similarity to the exec system call.
1516 It is an ongoing process to be certain the hardware in a machine
1517 is properly shutdown, so do not be surprised if this code does not
1518 initially work for you. It may help to enable device hotplugging
1519 support. As of this writing the exact hardware interface is
1520 strongly in flux, so no good recommendation can be made.
1523 bool "kernel crash dumps"
1524 depends on X86_64 || (X86_32 && HIGHMEM)
1526 Generate crash dump after being started by kexec.
1527 This should be normally only set in special crash dump kernels
1528 which are loaded in the main kernel with kexec-tools into
1529 a specially reserved region and then later executed after
1530 a crash by kdump/kexec. The crash dump kernel must be compiled
1531 to a memory address not used by the main kernel or BIOS using
1532 PHYSICAL_START, or it must be built as a relocatable image
1533 (CONFIG_RELOCATABLE=y).
1534 For more details see Documentation/kdump/kdump.txt
1537 bool "kexec jump (EXPERIMENTAL)"
1538 depends on EXPERIMENTAL
1539 depends on KEXEC && HIBERNATION
1541 Jump between original kernel and kexeced kernel and invoke
1542 code in physical address mode via KEXEC
1544 config PHYSICAL_START
1545 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1548 This gives the physical address where the kernel is loaded.
1550 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1551 bzImage will decompress itself to above physical address and
1552 run from there. Otherwise, bzImage will run from the address where
1553 it has been loaded by the boot loader and will ignore above physical
1556 In normal kdump cases one does not have to set/change this option
1557 as now bzImage can be compiled as a completely relocatable image
1558 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1559 address. This option is mainly useful for the folks who don't want
1560 to use a bzImage for capturing the crash dump and want to use a
1561 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1562 to be specifically compiled to run from a specific memory area
1563 (normally a reserved region) and this option comes handy.
1565 So if you are using bzImage for capturing the crash dump,
1566 leave the value here unchanged to 0x1000000 and set
1567 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1568 for capturing the crash dump change this value to start of
1569 the reserved region. In other words, it can be set based on
1570 the "X" value as specified in the "crashkernel=YM@XM"
1571 command line boot parameter passed to the panic-ed
1572 kernel. Please take a look at Documentation/kdump/kdump.txt
1573 for more details about crash dumps.
1575 Usage of bzImage for capturing the crash dump is recommended as
1576 one does not have to build two kernels. Same kernel can be used
1577 as production kernel and capture kernel. Above option should have
1578 gone away after relocatable bzImage support is introduced. But it
1579 is present because there are users out there who continue to use
1580 vmlinux for dump capture. This option should go away down the
1583 Don't change this unless you know what you are doing.
1586 bool "Build a relocatable kernel"
1589 This builds a kernel image that retains relocation information
1590 so it can be loaded someplace besides the default 1MB.
1591 The relocations tend to make the kernel binary about 10% larger,
1592 but are discarded at runtime.
1594 One use is for the kexec on panic case where the recovery kernel
1595 must live at a different physical address than the primary
1598 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1599 it has been loaded at and the compile time physical address
1600 (CONFIG_PHYSICAL_START) is ignored.
1602 # Relocation on x86-32 needs some additional build support
1603 config X86_NEED_RELOCS
1605 depends on X86_32 && RELOCATABLE
1607 config PHYSICAL_ALIGN
1608 hex "Alignment value to which kernel should be aligned" if X86_32
1610 range 0x2000 0x1000000
1612 This value puts the alignment restrictions on physical address
1613 where kernel is loaded and run from. Kernel is compiled for an
1614 address which meets above alignment restriction.
1616 If bootloader loads the kernel at a non-aligned address and
1617 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1618 address aligned to above value and run from there.
1620 If bootloader loads the kernel at a non-aligned address and
1621 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1622 load address and decompress itself to the address it has been
1623 compiled for and run from there. The address for which kernel is
1624 compiled already meets above alignment restrictions. Hence the
1625 end result is that kernel runs from a physical address meeting
1626 above alignment restrictions.
1628 Don't change this unless you know what you are doing.
1631 bool "Support for hot-pluggable CPUs"
1632 depends on SMP && HOTPLUG
1634 Say Y here to allow turning CPUs off and on. CPUs can be
1635 controlled through /sys/devices/system/cpu.
1636 ( Note: power management support will enable this option
1637 automatically on SMP systems. )
1638 Say N if you want to disable CPU hotplug.
1642 prompt "Compat VDSO support"
1643 depends on X86_32 || IA32_EMULATION
1645 Map the 32-bit VDSO to the predictable old-style address too.
1647 Say N here if you are running a sufficiently recent glibc
1648 version (2.3.3 or later), to remove the high-mapped
1649 VDSO mapping and to exclusively use the randomized VDSO.
1654 bool "Built-in kernel command line"
1656 Allow for specifying boot arguments to the kernel at
1657 build time. On some systems (e.g. embedded ones), it is
1658 necessary or convenient to provide some or all of the
1659 kernel boot arguments with the kernel itself (that is,
1660 to not rely on the boot loader to provide them.)
1662 To compile command line arguments into the kernel,
1663 set this option to 'Y', then fill in the
1664 the boot arguments in CONFIG_CMDLINE.
1666 Systems with fully functional boot loaders (i.e. non-embedded)
1667 should leave this option set to 'N'.
1670 string "Built-in kernel command string"
1671 depends on CMDLINE_BOOL
1674 Enter arguments here that should be compiled into the kernel
1675 image and used at boot time. If the boot loader provides a
1676 command line at boot time, it is appended to this string to
1677 form the full kernel command line, when the system boots.
1679 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1680 change this behavior.
1682 In most cases, the command line (whether built-in or provided
1683 by the boot loader) should specify the device for the root
1686 config CMDLINE_OVERRIDE
1687 bool "Built-in command line overrides boot loader arguments"
1688 depends on CMDLINE_BOOL
1690 Set this option to 'Y' to have the kernel ignore the boot loader
1691 command line, and use ONLY the built-in command line.
1693 This is used to work around broken boot loaders. This should
1694 be set to 'N' under normal conditions.
1698 config ARCH_ENABLE_MEMORY_HOTPLUG
1700 depends on X86_64 || (X86_32 && HIGHMEM)
1702 config ARCH_ENABLE_MEMORY_HOTREMOVE
1704 depends on MEMORY_HOTPLUG
1706 config HAVE_ARCH_EARLY_PFN_TO_NID
1710 config USE_PERCPU_NUMA_NODE_ID
1714 menu "Power management and ACPI options"
1716 config ARCH_HIBERNATION_HEADER
1718 depends on X86_64 && HIBERNATION
1720 source "kernel/power/Kconfig"
1722 source "drivers/acpi/Kconfig"
1724 source "drivers/sfi/Kconfig"
1728 depends on APM || APM_MODULE
1731 tristate "APM (Advanced Power Management) BIOS support"
1732 depends on X86_32 && PM_SLEEP
1734 APM is a BIOS specification for saving power using several different
1735 techniques. This is mostly useful for battery powered laptops with
1736 APM compliant BIOSes. If you say Y here, the system time will be
1737 reset after a RESUME operation, the /proc/apm device will provide
1738 battery status information, and user-space programs will receive
1739 notification of APM "events" (e.g. battery status change).
1741 If you select "Y" here, you can disable actual use of the APM
1742 BIOS by passing the "apm=off" option to the kernel at boot time.
1744 Note that the APM support is almost completely disabled for
1745 machines with more than one CPU.
1747 In order to use APM, you will need supporting software. For location
1748 and more information, read <file:Documentation/power/pm.txt> and the
1749 Battery Powered Linux mini-HOWTO, available from
1750 <http://www.tldp.org/docs.html#howto>.
1752 This driver does not spin down disk drives (see the hdparm(8)
1753 manpage ("man 8 hdparm") for that), and it doesn't turn off
1754 VESA-compliant "green" monitors.
1756 This driver does not support the TI 4000M TravelMate and the ACER
1757 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1758 desktop machines also don't have compliant BIOSes, and this driver
1759 may cause those machines to panic during the boot phase.
1761 Generally, if you don't have a battery in your machine, there isn't
1762 much point in using this driver and you should say N. If you get
1763 random kernel OOPSes or reboots that don't seem to be related to
1764 anything, try disabling/enabling this option (or disabling/enabling
1767 Some other things you should try when experiencing seemingly random,
1770 1) make sure that you have enough swap space and that it is
1772 2) pass the "no-hlt" option to the kernel
1773 3) switch on floating point emulation in the kernel and pass
1774 the "no387" option to the kernel
1775 4) pass the "floppy=nodma" option to the kernel
1776 5) pass the "mem=4M" option to the kernel (thereby disabling
1777 all but the first 4 MB of RAM)
1778 6) make sure that the CPU is not over clocked.
1779 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1780 8) disable the cache from your BIOS settings
1781 9) install a fan for the video card or exchange video RAM
1782 10) install a better fan for the CPU
1783 11) exchange RAM chips
1784 12) exchange the motherboard.
1786 To compile this driver as a module, choose M here: the
1787 module will be called apm.
1791 config APM_IGNORE_USER_SUSPEND
1792 bool "Ignore USER SUSPEND"
1794 This option will ignore USER SUSPEND requests. On machines with a
1795 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1796 series notebooks, it is necessary to say Y because of a BIOS bug.
1798 config APM_DO_ENABLE
1799 bool "Enable PM at boot time"
1801 Enable APM features at boot time. From page 36 of the APM BIOS
1802 specification: "When disabled, the APM BIOS does not automatically
1803 power manage devices, enter the Standby State, enter the Suspend
1804 State, or take power saving steps in response to CPU Idle calls."
1805 This driver will make CPU Idle calls when Linux is idle (unless this
1806 feature is turned off -- see "Do CPU IDLE calls", below). This
1807 should always save battery power, but more complicated APM features
1808 will be dependent on your BIOS implementation. You may need to turn
1809 this option off if your computer hangs at boot time when using APM
1810 support, or if it beeps continuously instead of suspending. Turn
1811 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1812 T400CDT. This is off by default since most machines do fine without
1816 bool "Make CPU Idle calls when idle"
1818 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1819 On some machines, this can activate improved power savings, such as
1820 a slowed CPU clock rate, when the machine is idle. These idle calls
1821 are made after the idle loop has run for some length of time (e.g.,
1822 333 mS). On some machines, this will cause a hang at boot time or
1823 whenever the CPU becomes idle. (On machines with more than one CPU,
1824 this option does nothing.)
1826 config APM_DISPLAY_BLANK
1827 bool "Enable console blanking using APM"
1829 Enable console blanking using the APM. Some laptops can use this to
1830 turn off the LCD backlight when the screen blanker of the Linux
1831 virtual console blanks the screen. Note that this is only used by
1832 the virtual console screen blanker, and won't turn off the backlight
1833 when using the X Window system. This also doesn't have anything to
1834 do with your VESA-compliant power-saving monitor. Further, this
1835 option doesn't work for all laptops -- it might not turn off your
1836 backlight at all, or it might print a lot of errors to the console,
1837 especially if you are using gpm.
1839 config APM_ALLOW_INTS
1840 bool "Allow interrupts during APM BIOS calls"
1842 Normally we disable external interrupts while we are making calls to
1843 the APM BIOS as a measure to lessen the effects of a badly behaving
1844 BIOS implementation. The BIOS should reenable interrupts if it
1845 needs to. Unfortunately, some BIOSes do not -- especially those in
1846 many of the newer IBM Thinkpads. If you experience hangs when you
1847 suspend, try setting this to Y. Otherwise, say N.
1851 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1853 source "drivers/cpuidle/Kconfig"
1855 source "drivers/idle/Kconfig"
1860 menu "Bus options (PCI etc.)"
1865 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1867 Find out whether you have a PCI motherboard. PCI is the name of a
1868 bus system, i.e. the way the CPU talks to the other stuff inside
1869 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1870 VESA. If you have PCI, say Y, otherwise N.
1873 prompt "PCI access mode"
1874 depends on X86_32 && PCI
1877 On PCI systems, the BIOS can be used to detect the PCI devices and
1878 determine their configuration. However, some old PCI motherboards
1879 have BIOS bugs and may crash if this is done. Also, some embedded
1880 PCI-based systems don't have any BIOS at all. Linux can also try to
1881 detect the PCI hardware directly without using the BIOS.
1883 With this option, you can specify how Linux should detect the
1884 PCI devices. If you choose "BIOS", the BIOS will be used,
1885 if you choose "Direct", the BIOS won't be used, and if you
1886 choose "MMConfig", then PCI Express MMCONFIG will be used.
1887 If you choose "Any", the kernel will try MMCONFIG, then the
1888 direct access method and falls back to the BIOS if that doesn't
1889 work. If unsure, go with the default, which is "Any".
1894 config PCI_GOMMCONFIG
1911 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1913 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1916 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1920 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1924 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1931 bool "Support mmconfig PCI config space access"
1932 depends on X86_64 && PCI && ACPI
1934 config PCI_CNB20LE_QUIRK
1935 bool "Read CNB20LE Host Bridge Windows"
1938 Read the PCI windows out of the CNB20LE host bridge. This allows
1939 PCI hotplug to work on systems with the CNB20LE chipset which do
1943 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1944 depends on PCI_MSI && ACPI && EXPERIMENTAL
1946 DMA remapping (DMAR) devices support enables independent address
1947 translations for Direct Memory Access (DMA) from devices.
1948 These DMA remapping devices are reported via ACPI tables
1949 and include PCI device scope covered by these DMA
1952 config DMAR_DEFAULT_ON
1954 prompt "Enable DMA Remapping Devices by default"
1957 Selecting this option will enable a DMAR device at boot time if
1958 one is found. If this option is not selected, DMAR support can
1959 be enabled by passing intel_iommu=on to the kernel. It is
1960 recommended you say N here while the DMAR code remains
1963 config DMAR_BROKEN_GFX_WA
1964 bool "Workaround broken graphics drivers (going away soon)"
1965 depends on DMAR && BROKEN
1967 Current Graphics drivers tend to use physical address
1968 for DMA and avoid using DMA APIs. Setting this config
1969 option permits the IOMMU driver to set a unity map for
1970 all the OS-visible memory. Hence the driver can continue
1971 to use physical addresses for DMA, at least until this
1972 option is removed in the 2.6.32 kernel.
1974 config DMAR_FLOPPY_WA
1978 Floppy disk drivers are known to bypass DMA API calls
1979 thereby failing to work when IOMMU is enabled. This
1980 workaround will setup a 1:1 mapping for the first
1981 16MiB to make floppy (an ISA device) work.
1984 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1985 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1987 Supports Interrupt remapping for IO-APIC and MSI devices.
1988 To use x2apic mode in the CPU's which support x2APIC enhancements or
1989 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1991 source "drivers/pci/pcie/Kconfig"
1993 source "drivers/pci/Kconfig"
1995 # x86_64 have no ISA slots, but do have ISA-style DMA.
2004 Find out whether you have ISA slots on your motherboard. ISA is the
2005 name of a bus system, i.e. the way the CPU talks to the other stuff
2006 inside your box. Other bus systems are PCI, EISA, MicroChannel
2007 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2008 newer boards don't support it. If you have ISA, say Y, otherwise N.
2014 The Extended Industry Standard Architecture (EISA) bus was
2015 developed as an open alternative to the IBM MicroChannel bus.
2017 The EISA bus provided some of the features of the IBM MicroChannel
2018 bus while maintaining backward compatibility with cards made for
2019 the older ISA bus. The EISA bus saw limited use between 1988 and
2020 1995 when it was made obsolete by the PCI bus.
2022 Say Y here if you are building a kernel for an EISA-based machine.
2026 source "drivers/eisa/Kconfig"
2031 MicroChannel Architecture is found in some IBM PS/2 machines and
2032 laptops. It is a bus system similar to PCI or ISA. See
2033 <file:Documentation/mca.txt> (and especially the web page given
2034 there) before attempting to build an MCA bus kernel.
2036 source "drivers/mca/Kconfig"
2039 tristate "NatSemi SCx200 support"
2041 This provides basic support for National Semiconductor's
2042 (now AMD's) Geode processors. The driver probes for the
2043 PCI-IDs of several on-chip devices, so its a good dependency
2044 for other scx200_* drivers.
2046 If compiled as a module, the driver is named scx200.
2048 config SCx200HR_TIMER
2049 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2050 depends on SCx200 && GENERIC_TIME
2053 This driver provides a clocksource built upon the on-chip
2054 27MHz high-resolution timer. Its also a workaround for
2055 NSC Geode SC-1100's buggy TSC, which loses time when the
2056 processor goes idle (as is done by the scheduler). The
2057 other workaround is idle=poll boot option.
2060 bool "One Laptop Per Child support"
2063 Add support for detecting the unique features of the OLPC
2070 depends on CPU_SUP_AMD && PCI
2072 source "drivers/pcmcia/Kconfig"
2074 source "drivers/pci/hotplug/Kconfig"
2079 menu "Executable file formats / Emulations"
2081 source "fs/Kconfig.binfmt"
2083 config IA32_EMULATION
2084 bool "IA32 Emulation"
2086 select COMPAT_BINFMT_ELF
2088 Include code to run 32-bit programs under a 64-bit kernel. You should
2089 likely turn this on, unless you're 100% sure that you don't have any
2090 32-bit programs left.
2093 tristate "IA32 a.out support"
2094 depends on IA32_EMULATION
2096 Support old a.out binaries in the 32bit emulation.
2100 depends on IA32_EMULATION
2102 config COMPAT_FOR_U64_ALIGNMENT
2106 config SYSVIPC_COMPAT
2108 depends on COMPAT && SYSVIPC
2113 config HAVE_ATOMIC_IOMAP
2117 source "net/Kconfig"
2119 source "drivers/Kconfig"
2121 source "drivers/firmware/Kconfig"
2125 source "arch/x86/Kconfig.debug"
2127 source "security/Kconfig"
2129 source "crypto/Kconfig"
2131 source "arch/x86/kvm/Kconfig"
2133 source "lib/Kconfig"