3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
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
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_PERF_EVENTS_NMI
61 select HAVE_ARCH_KMEMCHECK
62 select HAVE_USER_RETURN_NOTIFIER
63 select HAVE_ARCH_JUMP_LABEL
64 select HAVE_TEXT_POKE_SMP
65 select HAVE_GENERIC_HARDIRQS
66 select HAVE_SPARSE_IRQ
68 select GENERIC_FIND_FIRST_BIT
69 select GENERIC_IRQ_PROBE
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_IRQ_SHOW
72 select GENERIC_CLOCKEVENTS_MIN_ADJUST
73 select IRQ_FORCED_THREADING
74 select USE_GENERIC_SMP_HELPERS if SMP
75 select HAVE_BPF_JIT if (X86_64 && NET)
76 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
78 select ARCH_HAVE_NMI_SAFE_CMPXCHG
79 select ARCH_SUPPORTS_ATOMIC_RMW
81 config INSTRUCTION_DECODER
82 def_bool (KPROBES || PERF_EVENTS)
86 default "elf32-i386" if X86_32
87 default "elf64-x86-64" if X86_64
91 default "arch/x86/configs/i386_defconfig" if X86_32
92 default "arch/x86/configs/x86_64_defconfig" if X86_64
94 config GENERIC_CMOS_UPDATE
97 config CLOCKSOURCE_WATCHDOG
100 config GENERIC_CLOCKEVENTS
103 config ARCH_CLOCKSOURCE_DATA
107 config GENERIC_CLOCKEVENTS_BROADCAST
109 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
111 config LOCKDEP_SUPPORT
114 config STACKTRACE_SUPPORT
117 config HAVE_LATENCYTOP_SUPPORT
124 bool "DMA memory allocation support" if EXPERT
127 DMA memory allocation support allows devices with less than 32-bit
128 addressing to allocate within the first 16MB of address space.
129 Disable if no such devices will be used.
136 config NEED_DMA_MAP_STATE
138 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
140 config NEED_SG_DMA_LENGTH
143 config GENERIC_ISA_DMA
152 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
154 config GENERIC_BUG_RELATIVE_POINTERS
157 config GENERIC_HWEIGHT
163 config ARCH_MAY_HAVE_PC_FDC
166 config RWSEM_GENERIC_SPINLOCK
169 config RWSEM_XCHGADD_ALGORITHM
172 config ARCH_HAS_CPU_IDLE_WAIT
175 config GENERIC_CALIBRATE_DELAY
178 config GENERIC_TIME_VSYSCALL
182 config ARCH_HAS_CPU_RELAX
185 config ARCH_HAS_DEFAULT_IDLE
188 config ARCH_HAS_CACHE_LINE_SIZE
191 config HAVE_SETUP_PER_CPU_AREA
194 config NEED_PER_CPU_EMBED_FIRST_CHUNK
197 config NEED_PER_CPU_PAGE_FIRST_CHUNK
200 config ARCH_HIBERNATION_POSSIBLE
203 config ARCH_SUSPEND_POSSIBLE
210 config ARCH_POPULATES_NODE_MAP
217 config ARCH_SUPPORTS_OPTIMIZED_INLINING
220 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
223 config HAVE_INTEL_TXT
225 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
229 depends on X86_32 && SMP
233 depends on X86_64 && SMP
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/x86/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 && IRQ_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 "Enable MPS table" if ACPI
304 depends on X86_LOCAL_APIC
306 For old smp systems that do not have proper acpi support. Newer systems
307 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
310 bool "Support for big SMP systems with more than 8 CPUs"
311 depends on X86_32 && SMP
313 This option is needed for the systems that have more than 8 CPUs
316 config X86_EXTENDED_PLATFORM
317 bool "Support for extended (non-PC) x86 platforms"
320 If you disable this option then the kernel will only support
321 standard PC platforms. (which covers the vast majority of
324 If you enable this option then you'll be able to select support
325 for the following (non-PC) 32 bit x86 platforms:
329 SGI 320/540 (Visual Workstation)
330 Summit/EXA (IBM x440)
331 Unisys ES7000 IA32 series
332 Moorestown MID devices
334 If you have one of these systems, or if you want to build a
335 generic distribution kernel, say Y here - otherwise say N.
339 config X86_EXTENDED_PLATFORM
340 bool "Support for extended (non-PC) x86 platforms"
343 If you disable this option then the kernel will only support
344 standard PC platforms. (which covers the vast majority of
347 If you enable this option then you'll be able to select support
348 for the following (non-PC) 64 bit x86 platforms:
352 If you have one of these systems, or if you want to build a
353 generic distribution kernel, say Y here - otherwise say N.
355 # This is an alphabetically sorted list of 64 bit extended platforms
356 # Please maintain the alphabetic order if and when there are additions
360 select PARAVIRT_GUEST
362 depends on X86_64 && PCI
363 depends on X86_EXTENDED_PLATFORM
365 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
366 supposed to run on these EM64T-based machines. Only choose this option
367 if you have one of these machines.
370 bool "SGI Ultraviolet"
372 depends on X86_EXTENDED_PLATFORM
374 depends on X86_X2APIC
376 This option is needed in order to support SGI Ultraviolet systems.
377 If you don't have one of these, you should say N here.
379 # Following is an alphabetically sorted list of 32 bit extended platforms
380 # Please maintain the alphabetic order if and when there are additions
383 bool "CE4100 TV platform"
385 depends on PCI_GODIRECT
387 depends on X86_EXTENDED_PLATFORM
388 select X86_REBOOTFIXUPS
390 select OF_EARLY_FLATTREE
392 Select for the Intel CE media processor (CE4100) SOC.
393 This option compiles in support for the CE4100 SOC for settop
394 boxes and media devices.
396 config X86_WANT_INTEL_MID
397 bool "Intel MID platform support"
399 depends on X86_EXTENDED_PLATFORM
401 Select to build a kernel capable of supporting Intel MID platform
402 systems which do not have the PCI legacy interfaces (Moorestown,
403 Medfield). If you are building for a PC class system say N here.
405 if X86_WANT_INTEL_MID
411 bool "Moorestown MID platform"
414 depends on X86_IO_APIC
419 select X86_PLATFORM_DEVICES
422 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
423 Internet Device(MID) platform. Moorestown consists of two chips:
424 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
425 Unlike standard x86 PCs, Moorestown does not have many legacy devices
426 nor standard legacy replacement devices/features. e.g. Moorestown does
427 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
432 bool "RDC R-321x SoC"
434 depends on X86_EXTENDED_PLATFORM
436 select X86_REBOOTFIXUPS
438 This option is needed for RDC R-321x system-on-chip, also known
440 If you don't have one of these chips, you should say N here.
442 config X86_32_NON_STANDARD
443 bool "Support non-standard 32-bit SMP architectures"
444 depends on X86_32 && SMP
445 depends on X86_EXTENDED_PLATFORM
447 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
448 subarchitectures. It is intended for a generic binary kernel.
449 if you select them all, kernel will probe it one by one. and will
452 # Alphabetically sorted list of Non standard 32 bit platforms
455 bool "NUMAQ (IBM/Sequent)"
456 depends on X86_32_NON_STANDARD
461 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
462 NUMA multiquad box. This changes the way that processors are
463 bootstrapped, and uses Clustered Logical APIC addressing mode instead
464 of Flat Logical. You will need a new lynxer.elf file to flash your
465 firmware with - send email to <Martin.Bligh@us.ibm.com>.
467 config X86_SUPPORTS_MEMORY_FAILURE
469 # MCE code calls memory_failure():
471 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
472 depends on !X86_NUMAQ
473 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
474 depends on X86_64 || !SPARSEMEM
475 select ARCH_SUPPORTS_MEMORY_FAILURE
478 bool "SGI 320/540 (Visual Workstation)"
479 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
480 depends on X86_32_NON_STANDARD
482 The SGI Visual Workstation series is an IA32-based workstation
483 based on SGI systems chips with some legacy PC hardware attached.
485 Say Y here to create a kernel to run on the SGI 320 or 540.
487 A kernel compiled for the Visual Workstation will run on general
488 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
491 bool "Summit/EXA (IBM x440)"
492 depends on X86_32_NON_STANDARD
494 This option is needed for IBM systems that use the Summit/EXA chipset.
495 In particular, it is needed for the x440.
498 bool "Unisys ES7000 IA32 series"
499 depends on X86_32_NON_STANDARD && X86_BIGSMP
501 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
502 supposed to run on an IA32-based Unisys ES7000 system.
505 tristate "Eurobraille/Iris poweroff module"
508 The Iris machines from EuroBraille do not have APM or ACPI support
509 to shut themselves down properly. A special I/O sequence is
510 needed to do so, which is what this module does at
513 This is only for Iris machines from EuroBraille.
517 config SCHED_OMIT_FRAME_POINTER
519 prompt "Single-depth WCHAN output"
522 Calculate simpler /proc/<PID>/wchan values. If this option
523 is disabled then wchan values will recurse back to the
524 caller function. This provides more accurate wchan values,
525 at the expense of slightly more scheduling overhead.
527 If in doubt, say "Y".
529 menuconfig PARAVIRT_GUEST
530 bool "Paravirtualized guest support"
532 Say Y here to get to see options related to running Linux under
533 various hypervisors. This option alone does not add any kernel code.
535 If you say N, all options in this submenu will be skipped and disabled.
539 config PARAVIRT_TIME_ACCOUNTING
540 bool "Paravirtual steal time accounting"
544 Select this option to enable fine granularity task steal time
545 accounting. Time spent executing other tasks in parallel with
546 the current vCPU is discounted from the vCPU power. To account for
547 that, there can be a small performance impact.
549 If in doubt, say N here.
551 source "arch/x86/xen/Kconfig"
554 bool "KVM paravirtualized clock"
556 select PARAVIRT_CLOCK
558 Turning on this option will allow you to run a paravirtualized clock
559 when running over the KVM hypervisor. Instead of relying on a PIT
560 (or probably other) emulation by the underlying device model, the host
561 provides the guest with timing infrastructure such as time of day, and
565 bool "KVM Guest support"
568 This option enables various optimizations for running under the KVM
571 source "arch/x86/lguest/Kconfig"
574 bool "Enable paravirtualization code"
576 This changes the kernel so it can modify itself when it is run
577 under a hypervisor, potentially improving performance significantly
578 over full virtualization. However, when run without a hypervisor
579 the kernel is theoretically slower and slightly larger.
581 config PARAVIRT_SPINLOCKS
582 bool "Paravirtualization layer for spinlocks"
583 depends on PARAVIRT && SMP && EXPERIMENTAL
585 Paravirtualized spinlocks allow a pvops backend to replace the
586 spinlock implementation with something virtualization-friendly
587 (for example, block the virtual CPU rather than spinning).
589 Unfortunately the downside is an up to 5% performance hit on
590 native kernels, with various workloads.
592 If you are unsure how to answer this question, answer N.
594 config PARAVIRT_CLOCK
599 config PARAVIRT_DEBUG
600 bool "paravirt-ops debugging"
601 depends on PARAVIRT && DEBUG_KERNEL
603 Enable to debug paravirt_ops internals. Specifically, BUG if
604 a paravirt_op is missing when it is called.
612 This option adds a kernel parameter 'memtest', which allows memtest
614 memtest=0, mean disabled; -- default
615 memtest=1, mean do 1 test pattern;
617 memtest=4, mean do 4 test patterns.
618 If you are unsure how to answer this question, answer N.
620 config X86_SUMMIT_NUMA
622 depends on X86_32 && NUMA && X86_32_NON_STANDARD
624 config X86_CYCLONE_TIMER
626 depends on X86_32_NON_STANDARD
628 source "arch/x86/Kconfig.cpu"
632 prompt "HPET Timer Support" if X86_32
634 Use the IA-PC HPET (High Precision Event Timer) to manage
635 time in preference to the PIT and RTC, if a HPET is
637 HPET is the next generation timer replacing legacy 8254s.
638 The HPET provides a stable time base on SMP
639 systems, unlike the TSC, but it is more expensive to access,
640 as it is off-chip. You can find the HPET spec at
641 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
643 You can safely choose Y here. However, HPET will only be
644 activated if the platform and the BIOS support this feature.
645 Otherwise the 8254 will be used for timing services.
647 Choose N to continue using the legacy 8254 timer.
649 config HPET_EMULATE_RTC
651 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
655 prompt "Langwell APB Timer Support" if X86_MRST
658 APB timer is the replacement for 8254, HPET on X86 MID platforms.
659 The APBT provides a stable time base on SMP
660 systems, unlike the TSC, but it is more expensive to access,
661 as it is off-chip. APB timers are always running regardless of CPU
662 C states, they are used as per CPU clockevent device when possible.
664 # Mark as expert because too many people got it wrong.
665 # The code disables itself when not needed.
668 bool "Enable DMI scanning" if EXPERT
670 Enabled scanning of DMI to identify machine quirks. Say Y
671 here unless you have verified that your setup is not
672 affected by entries in the DMI blacklist. Required by PNP
676 bool "GART IOMMU support" if EXPERT
679 depends on X86_64 && PCI && AMD_NB
681 Support for full DMA access of devices with 32bit memory access only
682 on systems with more than 3GB. This is usually needed for USB,
683 sound, many IDE/SATA chipsets and some other devices.
684 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
685 based hardware IOMMU and a software bounce buffer based IOMMU used
686 on Intel systems and as fallback.
687 The code is only active when needed (enough memory and limited
688 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
692 bool "IBM Calgary IOMMU support"
694 depends on X86_64 && PCI && EXPERIMENTAL
696 Support for hardware IOMMUs in IBM's xSeries x366 and x460
697 systems. Needed to run systems with more than 3GB of memory
698 properly with 32-bit PCI devices that do not support DAC
699 (Double Address Cycle). Calgary also supports bus level
700 isolation, where all DMAs pass through the IOMMU. This
701 prevents them from going anywhere except their intended
702 destination. This catches hard-to-find kernel bugs and
703 mis-behaving drivers and devices that do not use the DMA-API
704 properly to set up their DMA buffers. The IOMMU can be
705 turned off at boot time with the iommu=off parameter.
706 Normally the kernel will make the right choice by itself.
709 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
711 prompt "Should Calgary be enabled by default?"
712 depends on CALGARY_IOMMU
714 Should Calgary be enabled by default? if you choose 'y', Calgary
715 will be used (if it exists). If you choose 'n', Calgary will not be
716 used even if it exists. If you choose 'n' and would like to use
717 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
720 # need this always selected by IOMMU for the VIA workaround
724 Support for software bounce buffers used on x86-64 systems
725 which don't have a hardware IOMMU (e.g. the current generation
726 of Intel's x86-64 CPUs). Using this PCI devices which can only
727 access 32-bits of memory can be used on systems with more than
728 3 GB of memory. If unsure, say Y.
731 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
734 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
735 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
736 select CPUMASK_OFFSTACK
738 Enable maximum number of CPUS and NUMA Nodes for this architecture.
742 int "Maximum number of CPUs" if SMP && !MAXSMP
743 range 2 8 if SMP && X86_32 && !X86_BIGSMP
744 range 2 512 if SMP && !MAXSMP
746 default "4096" if MAXSMP
747 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
750 This allows you to specify the maximum number of CPUs which this
751 kernel will support. The maximum supported value is 512 and the
752 minimum value which makes sense is 2.
754 This is purely to save memory - each supported CPU adds
755 approximately eight kilobytes to the kernel image.
758 bool "SMT (Hyperthreading) scheduler support"
761 SMT scheduler support improves the CPU scheduler's decision making
762 when dealing with Intel Pentium 4 chips with HyperThreading at a
763 cost of slightly increased overhead in some places. If unsure say
768 prompt "Multi-core scheduler support"
771 Multi-core scheduler support improves the CPU scheduler's decision
772 making when dealing with multi-core CPU chips at a cost of slightly
773 increased overhead in some places. If unsure say N here.
775 config IRQ_TIME_ACCOUNTING
776 bool "Fine granularity task level IRQ time accounting"
779 Select this option to enable fine granularity task irq time
780 accounting. This is done by reading a timestamp on each
781 transitions between softirq and hardirq state, so there can be a
782 small performance impact.
784 If in doubt, say N here.
786 source "kernel/Kconfig.preempt"
789 bool "Local APIC support on uniprocessors"
790 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
792 A local APIC (Advanced Programmable Interrupt Controller) is an
793 integrated interrupt controller in the CPU. If you have a single-CPU
794 system which has a processor with a local APIC, you can say Y here to
795 enable and use it. If you say Y here even though your machine doesn't
796 have a local APIC, then the kernel will still run with no slowdown at
797 all. The local APIC supports CPU-generated self-interrupts (timer,
798 performance counters), and the NMI watchdog which detects hard
802 bool "IO-APIC support on uniprocessors"
803 depends on X86_UP_APIC
805 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
806 SMP-capable replacement for PC-style interrupt controllers. Most
807 SMP systems and many recent uniprocessor systems have one.
809 If you have a single-CPU system with an IO-APIC, you can say Y here
810 to use it. If you say Y here even though your machine doesn't have
811 an IO-APIC, then the kernel will still run with no slowdown at all.
813 config X86_LOCAL_APIC
815 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
819 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
821 config X86_VISWS_APIC
823 depends on X86_32 && X86_VISWS
825 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
826 bool "Reroute for broken boot IRQs"
827 depends on X86_IO_APIC
829 This option enables a workaround that fixes a source of
830 spurious interrupts. This is recommended when threaded
831 interrupt handling is used on systems where the generation of
832 superfluous "boot interrupts" cannot be disabled.
834 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
835 entry in the chipset's IO-APIC is masked (as, e.g. the RT
836 kernel does during interrupt handling). On chipsets where this
837 boot IRQ generation cannot be disabled, this workaround keeps
838 the original IRQ line masked so that only the equivalent "boot
839 IRQ" is delivered to the CPUs. The workaround also tells the
840 kernel to set up the IRQ handler on the boot IRQ line. In this
841 way only one interrupt is delivered to the kernel. Otherwise
842 the spurious second interrupt may cause the kernel to bring
843 down (vital) interrupt lines.
845 Only affects "broken" chipsets. Interrupt sharing may be
846 increased on these systems.
849 bool "Machine Check / overheating reporting"
851 Machine Check support allows the processor to notify the
852 kernel if it detects a problem (e.g. overheating, data corruption).
853 The action the kernel takes depends on the severity of the problem,
854 ranging from warning messages to halting the machine.
858 prompt "Intel MCE features"
859 depends on X86_MCE && X86_LOCAL_APIC
861 Additional support for intel specific MCE features such as
866 prompt "AMD MCE features"
867 depends on X86_MCE && X86_LOCAL_APIC
869 Additional support for AMD specific MCE features such as
870 the DRAM Error Threshold.
872 config X86_ANCIENT_MCE
873 bool "Support for old Pentium 5 / WinChip machine checks"
874 depends on X86_32 && X86_MCE
876 Include support for machine check handling on old Pentium 5 or WinChip
877 systems. These typically need to be enabled explicitely on the command
880 config X86_MCE_THRESHOLD
881 depends on X86_MCE_AMD || X86_MCE_INTEL
884 config X86_MCE_INJECT
886 tristate "Machine check injector support"
888 Provide support for injecting machine checks for testing purposes.
889 If you don't know what a machine check is and you don't do kernel
890 QA it is safe to say n.
892 config X86_THERMAL_VECTOR
894 depends on X86_MCE_INTEL
897 bool "Enable VM86 support" if EXPERT
901 This option is required by programs like DOSEMU to run
902 16-bit real mode legacy code on x86 processors. It also may
903 be needed by software like XFree86 to initialize some video
904 cards via BIOS. Disabling this option saves about 6K.
907 bool "Enable support for 16-bit segments" if EXPERT
910 This option is required by programs like Wine to run 16-bit
911 protected mode legacy code on x86 processors. Disabling
912 this option saves about 300 bytes on i386, or around 6K text
913 plus 16K runtime memory on x86-64,
917 depends on X86_16BIT && X86_32
921 depends on X86_16BIT && X86_64
924 tristate "Toshiba Laptop support"
927 This adds a driver to safely access the System Management Mode of
928 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
929 not work on models with a Phoenix BIOS. The System Management Mode
930 is used to set the BIOS and power saving options on Toshiba portables.
932 For information on utilities to make use of this driver see the
933 Toshiba Linux utilities web site at:
934 <http://www.buzzard.org.uk/toshiba/>.
936 Say Y if you intend to run this kernel on a Toshiba portable.
940 tristate "Dell laptop support"
943 This adds a driver to safely access the System Management Mode
944 of the CPU on the Dell Inspiron 8000. The System Management Mode
945 is used to read cpu temperature and cooling fan status and to
946 control the fans on the I8K portables.
948 This driver has been tested only on the Inspiron 8000 but it may
949 also work with other Dell laptops. You can force loading on other
950 models by passing the parameter `force=1' to the module. Use at
953 For information on utilities to make use of this driver see the
954 I8K Linux utilities web site at:
955 <http://people.debian.org/~dz/i8k/>
957 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
960 config X86_REBOOTFIXUPS
961 bool "Enable X86 board specific fixups for reboot"
964 This enables chipset and/or board specific fixups to be done
965 in order to get reboot to work correctly. This is only needed on
966 some combinations of hardware and BIOS. The symptom, for which
967 this config is intended, is when reboot ends with a stalled/hung
970 Currently, the only fixup is for the Geode machines using
971 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
973 Say Y if you want to enable the fixup. Currently, it's safe to
974 enable this option even if you don't need it.
978 tristate "/dev/cpu/microcode - microcode support"
981 If you say Y here, you will be able to update the microcode on
982 certain Intel and AMD processors. The Intel support is for the
983 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
984 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
985 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
986 You will obviously need the actual microcode binary data itself
987 which is not shipped with the Linux kernel.
989 This option selects the general module only, you need to select
990 at least one vendor specific module as well.
992 To compile this driver as a module, choose M here: the
993 module will be called microcode.
995 config MICROCODE_INTEL
996 bool "Intel microcode patch loading support"
1001 This options enables microcode patch loading support for Intel
1004 For latest news and information on obtaining all the required
1005 Intel ingredients for this driver, check:
1006 <http://www.urbanmyth.org/microcode/>.
1008 config MICROCODE_AMD
1009 bool "AMD microcode patch loading support"
1010 depends on MICROCODE
1013 If you select this option, microcode patch loading support for AMD
1014 processors will be enabled.
1016 config MICROCODE_OLD_INTERFACE
1018 depends on MICROCODE
1021 tristate "/dev/cpu/*/msr - Model-specific register support"
1023 This device gives privileged processes access to the x86
1024 Model-Specific Registers (MSRs). It is a character device with
1025 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1026 MSR accesses are directed to a specific CPU on multi-processor
1030 tristate "/dev/cpu/*/cpuid - CPU information support"
1032 This device gives processes access to the x86 CPUID instruction to
1033 be executed on a specific processor. It is a character device
1034 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1038 prompt "High Memory Support"
1039 default HIGHMEM64G if X86_NUMAQ
1045 depends on !X86_NUMAQ
1047 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1048 However, the address space of 32-bit x86 processors is only 4
1049 Gigabytes large. That means that, if you have a large amount of
1050 physical memory, not all of it can be "permanently mapped" by the
1051 kernel. The physical memory that's not permanently mapped is called
1054 If you are compiling a kernel which will never run on a machine with
1055 more than 1 Gigabyte total physical RAM, answer "off" here (default
1056 choice and suitable for most users). This will result in a "3GB/1GB"
1057 split: 3GB are mapped so that each process sees a 3GB virtual memory
1058 space and the remaining part of the 4GB virtual memory space is used
1059 by the kernel to permanently map as much physical memory as
1062 If the machine has between 1 and 4 Gigabytes physical RAM, then
1065 If more than 4 Gigabytes is used then answer "64GB" here. This
1066 selection turns Intel PAE (Physical Address Extension) mode on.
1067 PAE implements 3-level paging on IA32 processors. PAE is fully
1068 supported by Linux, PAE mode is implemented on all recent Intel
1069 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1070 then the kernel will not boot on CPUs that don't support PAE!
1072 The actual amount of total physical memory will either be
1073 auto detected or can be forced by using a kernel command line option
1074 such as "mem=256M". (Try "man bootparam" or see the documentation of
1075 your boot loader (lilo or loadlin) about how to pass options to the
1076 kernel at boot time.)
1078 If unsure, say "off".
1082 depends on !X86_NUMAQ
1084 Select this if you have a 32-bit processor and between 1 and 4
1085 gigabytes of physical RAM.
1089 depends on !M386 && !M486
1092 Select this if you have a 32-bit processor and more than 4
1093 gigabytes of physical RAM.
1098 depends on EXPERIMENTAL
1099 prompt "Memory split" if EXPERT
1103 Select the desired split between kernel and user memory.
1105 If the address range available to the kernel is less than the
1106 physical memory installed, the remaining memory will be available
1107 as "high memory". Accessing high memory is a little more costly
1108 than low memory, as it needs to be mapped into the kernel first.
1109 Note that increasing the kernel address space limits the range
1110 available to user programs, making the address space there
1111 tighter. Selecting anything other than the default 3G/1G split
1112 will also likely make your kernel incompatible with binary-only
1115 If you are not absolutely sure what you are doing, leave this
1119 bool "3G/1G user/kernel split"
1120 config VMSPLIT_3G_OPT
1122 bool "3G/1G user/kernel split (for full 1G low memory)"
1124 bool "2G/2G user/kernel split"
1125 config VMSPLIT_2G_OPT
1127 bool "2G/2G user/kernel split (for full 2G low memory)"
1129 bool "1G/3G user/kernel split"
1134 default 0xB0000000 if VMSPLIT_3G_OPT
1135 default 0x80000000 if VMSPLIT_2G
1136 default 0x78000000 if VMSPLIT_2G_OPT
1137 default 0x40000000 if VMSPLIT_1G
1143 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1146 bool "PAE (Physical Address Extension) Support"
1147 depends on X86_32 && !HIGHMEM4G
1149 PAE is required for NX support, and furthermore enables
1150 larger swapspace support for non-overcommit purposes. It
1151 has the cost of more pagetable lookup overhead, and also
1152 consumes more pagetable space per process.
1154 config ARCH_PHYS_ADDR_T_64BIT
1155 def_bool X86_64 || X86_PAE
1157 config ARCH_DMA_ADDR_T_64BIT
1158 def_bool X86_64 || HIGHMEM64G
1160 config DIRECT_GBPAGES
1161 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1165 Allow the kernel linear mapping to use 1GB pages on CPUs that
1166 support it. This can improve the kernel's performance a tiny bit by
1167 reducing TLB pressure. If in doubt, say "Y".
1169 # Common NUMA Features
1171 bool "Numa Memory Allocation and Scheduler Support"
1173 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && BROKEN)
1174 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1176 Enable NUMA (Non Uniform Memory Access) support.
1178 The kernel will try to allocate memory used by a CPU on the
1179 local memory controller of the CPU and add some more
1180 NUMA awareness to the kernel.
1182 For 64-bit this is recommended if the system is Intel Core i7
1183 (or later), AMD Opteron, or EM64T NUMA.
1185 For 32-bit this is only needed on (rare) 32-bit-only platforms
1186 that support NUMA topologies, such as NUMAQ / Summit, or if you
1187 boot a 32-bit kernel on a 64-bit NUMA platform.
1189 Otherwise, you should say N.
1191 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1192 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1196 prompt "Old style AMD Opteron NUMA detection"
1197 depends on X86_64 && NUMA && PCI
1199 Enable AMD NUMA node topology detection. You should say Y here if
1200 you have a multi processor AMD system. This uses an old method to
1201 read the NUMA configuration directly from the builtin Northbridge
1202 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1203 which also takes priority if both are compiled in.
1205 config X86_64_ACPI_NUMA
1207 prompt "ACPI NUMA detection"
1208 depends on X86_64 && NUMA && ACPI && PCI
1211 Enable ACPI SRAT based node topology detection.
1213 # Some NUMA nodes have memory ranges that span
1214 # other nodes. Even though a pfn is valid and
1215 # between a node's start and end pfns, it may not
1216 # reside on that node. See memmap_init_zone()
1218 config NODES_SPAN_OTHER_NODES
1220 depends on X86_64_ACPI_NUMA
1223 bool "NUMA emulation"
1226 Enable NUMA emulation. A flat machine will be split
1227 into virtual nodes when booted with "numa=fake=N", where N is the
1228 number of nodes. This is only useful for debugging.
1231 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1233 default "10" if MAXSMP
1234 default "6" if X86_64
1235 default "4" if X86_NUMAQ
1237 depends on NEED_MULTIPLE_NODES
1239 Specify the maximum number of NUMA Nodes available on the target
1240 system. Increases memory reserved to accommodate various tables.
1242 config HAVE_ARCH_BOOTMEM
1244 depends on X86_32 && NUMA
1246 config HAVE_ARCH_ALLOC_REMAP
1248 depends on X86_32 && NUMA
1250 config ARCH_HAVE_MEMORY_PRESENT
1252 depends on X86_32 && DISCONTIGMEM
1254 config NEED_NODE_MEMMAP_SIZE
1256 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1258 config ARCH_FLATMEM_ENABLE
1260 depends on X86_32 && !NUMA
1262 config ARCH_DISCONTIGMEM_ENABLE
1264 depends on NUMA && X86_32
1266 config ARCH_DISCONTIGMEM_DEFAULT
1268 depends on NUMA && X86_32
1270 config ARCH_SPARSEMEM_ENABLE
1272 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1273 select SPARSEMEM_STATIC if X86_32
1274 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1276 config ARCH_SPARSEMEM_DEFAULT
1280 config ARCH_SELECT_MEMORY_MODEL
1282 depends on ARCH_SPARSEMEM_ENABLE
1284 config ARCH_MEMORY_PROBE
1286 depends on MEMORY_HOTPLUG
1288 config ARCH_PROC_KCORE_TEXT
1290 depends on X86_64 && PROC_KCORE
1292 config ILLEGAL_POINTER_VALUE
1295 default 0xdead000000000000 if X86_64
1300 bool "Allocate 3rd-level pagetables from highmem"
1303 The VM uses one page table entry for each page of physical memory.
1304 For systems with a lot of RAM, this can be wasteful of precious
1305 low memory. Setting this option will put user-space page table
1306 entries in high memory.
1308 config X86_CHECK_BIOS_CORRUPTION
1309 bool "Check for low memory corruption"
1311 Periodically check for memory corruption in low memory, which
1312 is suspected to be caused by BIOS. Even when enabled in the
1313 configuration, it is disabled at runtime. Enable it by
1314 setting "memory_corruption_check=1" on the kernel command
1315 line. By default it scans the low 64k of memory every 60
1316 seconds; see the memory_corruption_check_size and
1317 memory_corruption_check_period parameters in
1318 Documentation/kernel-parameters.txt to adjust this.
1320 When enabled with the default parameters, this option has
1321 almost no overhead, as it reserves a relatively small amount
1322 of memory and scans it infrequently. It both detects corruption
1323 and prevents it from affecting the running system.
1325 It is, however, intended as a diagnostic tool; if repeatable
1326 BIOS-originated corruption always affects the same memory,
1327 you can use memmap= to prevent the kernel from using that
1330 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1331 bool "Set the default setting of memory_corruption_check"
1332 depends on X86_CHECK_BIOS_CORRUPTION
1335 Set whether the default state of memory_corruption_check is
1338 config X86_RESERVE_LOW
1339 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1343 Specify the amount of low memory to reserve for the BIOS.
1345 The first page contains BIOS data structures that the kernel
1346 must not use, so that page must always be reserved.
1348 By default we reserve the first 64K of physical RAM, as a
1349 number of BIOSes are known to corrupt that memory range
1350 during events such as suspend/resume or monitor cable
1351 insertion, so it must not be used by the kernel.
1353 You can set this to 4 if you are absolutely sure that you
1354 trust the BIOS to get all its memory reservations and usages
1355 right. If you know your BIOS have problems beyond the
1356 default 64K area, you can set this to 640 to avoid using the
1357 entire low memory range.
1359 If you have doubts about the BIOS (e.g. suspend/resume does
1360 not work or there's kernel crashes after certain hardware
1361 hotplug events) then you might want to enable
1362 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1363 typical corruption patterns.
1365 Leave this to the default value of 64 if you are unsure.
1367 config MATH_EMULATION
1369 prompt "Math emulation" if X86_32
1371 Linux can emulate a math coprocessor (used for floating point
1372 operations) if you don't have one. 486DX and Pentium processors have
1373 a math coprocessor built in, 486SX and 386 do not, unless you added
1374 a 487DX or 387, respectively. (The messages during boot time can
1375 give you some hints here ["man dmesg"].) Everyone needs either a
1376 coprocessor or this emulation.
1378 If you don't have a math coprocessor, you need to say Y here; if you
1379 say Y here even though you have a coprocessor, the coprocessor will
1380 be used nevertheless. (This behavior can be changed with the kernel
1381 command line option "no387", which comes handy if your coprocessor
1382 is broken. Try "man bootparam" or see the documentation of your boot
1383 loader (lilo or loadlin) about how to pass options to the kernel at
1384 boot time.) This means that it is a good idea to say Y here if you
1385 intend to use this kernel on different machines.
1387 More information about the internals of the Linux math coprocessor
1388 emulation can be found in <file:arch/x86/math-emu/README>.
1390 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1391 kernel, it won't hurt.
1395 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1397 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1398 the Memory Type Range Registers (MTRRs) may be used to control
1399 processor access to memory ranges. This is most useful if you have
1400 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1401 allows bus write transfers to be combined into a larger transfer
1402 before bursting over the PCI/AGP bus. This can increase performance
1403 of image write operations 2.5 times or more. Saying Y here creates a
1404 /proc/mtrr file which may be used to manipulate your processor's
1405 MTRRs. Typically the X server should use this.
1407 This code has a reasonably generic interface so that similar
1408 control registers on other processors can be easily supported
1411 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1412 Registers (ARRs) which provide a similar functionality to MTRRs. For
1413 these, the ARRs are used to emulate the MTRRs.
1414 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1415 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1416 write-combining. All of these processors are supported by this code
1417 and it makes sense to say Y here if you have one of them.
1419 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1420 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1421 can lead to all sorts of problems, so it's good to say Y here.
1423 You can safely say Y even if your machine doesn't have MTRRs, you'll
1424 just add about 9 KB to your kernel.
1426 See <file:Documentation/x86/mtrr.txt> for more information.
1428 config MTRR_SANITIZER
1430 prompt "MTRR cleanup support"
1433 Convert MTRR layout from continuous to discrete, so X drivers can
1434 add writeback entries.
1436 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1437 The largest mtrr entry size for a continuous block can be set with
1442 config MTRR_SANITIZER_ENABLE_DEFAULT
1443 int "MTRR cleanup enable value (0-1)"
1446 depends on MTRR_SANITIZER
1448 Enable mtrr cleanup default value
1450 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1451 int "MTRR cleanup spare reg num (0-7)"
1454 depends on MTRR_SANITIZER
1456 mtrr cleanup spare entries default, it can be changed via
1457 mtrr_spare_reg_nr=N on the kernel command line.
1461 prompt "x86 PAT support" if EXPERT
1464 Use PAT attributes to setup page level cache control.
1466 PATs are the modern equivalents of MTRRs and are much more
1467 flexible than MTRRs.
1469 Say N here if you see bootup problems (boot crash, boot hang,
1470 spontaneous reboots) or a non-working video driver.
1474 config ARCH_USES_PG_UNCACHED
1480 prompt "x86 architectural random number generator" if EXPERT
1482 Enable the x86 architectural RDRAND instruction
1483 (Intel Bull Mountain technology) to generate random numbers.
1484 If supported, this is a high bandwidth, cryptographically
1485 secure hardware random number generator.
1488 bool "EFI runtime service support"
1491 This enables the kernel to use EFI runtime services that are
1492 available (such as the EFI variable services).
1494 This option is only useful on systems that have EFI firmware.
1495 In addition, you should use the latest ELILO loader available
1496 at <http://elilo.sourceforge.net> in order to take advantage
1497 of EFI runtime services. However, even with this option, the
1498 resultant kernel should continue to boot on existing non-EFI
1503 prompt "Enable seccomp to safely compute untrusted bytecode"
1505 This kernel feature is useful for number crunching applications
1506 that may need to compute untrusted bytecode during their
1507 execution. By using pipes or other transports made available to
1508 the process as file descriptors supporting the read/write
1509 syscalls, it's possible to isolate those applications in
1510 their own address space using seccomp. Once seccomp is
1511 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1512 and the task is only allowed to execute a few safe syscalls
1513 defined by each seccomp mode.
1515 If unsure, say Y. Only embedded should say N here.
1517 config CC_STACKPROTECTOR
1518 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1520 This option turns on the -fstack-protector GCC feature. This
1521 feature puts, at the beginning of functions, a canary value on
1522 the stack just before the return address, and validates
1523 the value just before actually returning. Stack based buffer
1524 overflows (that need to overwrite this return address) now also
1525 overwrite the canary, which gets detected and the attack is then
1526 neutralized via a kernel panic.
1528 This feature requires gcc version 4.2 or above, or a distribution
1529 gcc with the feature backported. Older versions are automatically
1530 detected and for those versions, this configuration option is
1531 ignored. (and a warning is printed during bootup)
1533 source kernel/Kconfig.hz
1536 bool "kexec system call"
1538 kexec is a system call that implements the ability to shutdown your
1539 current kernel, and to start another kernel. It is like a reboot
1540 but it is independent of the system firmware. And like a reboot
1541 you can start any kernel with it, not just Linux.
1543 The name comes from the similarity to the exec system call.
1545 It is an ongoing process to be certain the hardware in a machine
1546 is properly shutdown, so do not be surprised if this code does not
1547 initially work for you. It may help to enable device hotplugging
1548 support. As of this writing the exact hardware interface is
1549 strongly in flux, so no good recommendation can be made.
1552 bool "kernel crash dumps"
1553 depends on X86_64 || (X86_32 && HIGHMEM)
1555 Generate crash dump after being started by kexec.
1556 This should be normally only set in special crash dump kernels
1557 which are loaded in the main kernel with kexec-tools into
1558 a specially reserved region and then later executed after
1559 a crash by kdump/kexec. The crash dump kernel must be compiled
1560 to a memory address not used by the main kernel or BIOS using
1561 PHYSICAL_START, or it must be built as a relocatable image
1562 (CONFIG_RELOCATABLE=y).
1563 For more details see Documentation/kdump/kdump.txt
1566 bool "kexec jump (EXPERIMENTAL)"
1567 depends on EXPERIMENTAL
1568 depends on KEXEC && HIBERNATION
1570 Jump between original kernel and kexeced kernel and invoke
1571 code in physical address mode via KEXEC
1573 config PHYSICAL_START
1574 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1577 This gives the physical address where the kernel is loaded.
1579 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1580 bzImage will decompress itself to above physical address and
1581 run from there. Otherwise, bzImage will run from the address where
1582 it has been loaded by the boot loader and will ignore above physical
1585 In normal kdump cases one does not have to set/change this option
1586 as now bzImage can be compiled as a completely relocatable image
1587 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1588 address. This option is mainly useful for the folks who don't want
1589 to use a bzImage for capturing the crash dump and want to use a
1590 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1591 to be specifically compiled to run from a specific memory area
1592 (normally a reserved region) and this option comes handy.
1594 So if you are using bzImage for capturing the crash dump,
1595 leave the value here unchanged to 0x1000000 and set
1596 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1597 for capturing the crash dump change this value to start of
1598 the reserved region. In other words, it can be set based on
1599 the "X" value as specified in the "crashkernel=YM@XM"
1600 command line boot parameter passed to the panic-ed
1601 kernel. Please take a look at Documentation/kdump/kdump.txt
1602 for more details about crash dumps.
1604 Usage of bzImage for capturing the crash dump is recommended as
1605 one does not have to build two kernels. Same kernel can be used
1606 as production kernel and capture kernel. Above option should have
1607 gone away after relocatable bzImage support is introduced. But it
1608 is present because there are users out there who continue to use
1609 vmlinux for dump capture. This option should go away down the
1612 Don't change this unless you know what you are doing.
1615 bool "Build a relocatable kernel"
1618 This builds a kernel image that retains relocation information
1619 so it can be loaded someplace besides the default 1MB.
1620 The relocations tend to make the kernel binary about 10% larger,
1621 but are discarded at runtime.
1623 One use is for the kexec on panic case where the recovery kernel
1624 must live at a different physical address than the primary
1627 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1628 it has been loaded at and the compile time physical address
1629 (CONFIG_PHYSICAL_START) is ignored.
1631 # Relocation on x86-32 needs some additional build support
1632 config X86_NEED_RELOCS
1634 depends on X86_32 && RELOCATABLE
1636 config PHYSICAL_ALIGN
1637 hex "Alignment value to which kernel should be aligned" if X86_32
1639 range 0x2000 0x1000000
1641 This value puts the alignment restrictions on physical address
1642 where kernel is loaded and run from. Kernel is compiled for an
1643 address which meets above alignment restriction.
1645 If bootloader loads the kernel at a non-aligned address and
1646 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1647 address aligned to above value and run from there.
1649 If bootloader loads the kernel at a non-aligned address and
1650 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1651 load address and decompress itself to the address it has been
1652 compiled for and run from there. The address for which kernel is
1653 compiled already meets above alignment restrictions. Hence the
1654 end result is that kernel runs from a physical address meeting
1655 above alignment restrictions.
1657 Don't change this unless you know what you are doing.
1660 bool "Support for hot-pluggable CPUs"
1661 depends on SMP && HOTPLUG
1663 Say Y here to allow turning CPUs off and on. CPUs can be
1664 controlled through /sys/devices/system/cpu.
1665 ( Note: power management support will enable this option
1666 automatically on SMP systems. )
1667 Say N if you want to disable CPU hotplug.
1671 prompt "Compat VDSO support"
1672 depends on X86_32 || IA32_EMULATION
1674 Map the 32-bit VDSO to the predictable old-style address too.
1676 Say N here if you are running a sufficiently recent glibc
1677 version (2.3.3 or later), to remove the high-mapped
1678 VDSO mapping and to exclusively use the randomized VDSO.
1683 bool "Built-in kernel command line"
1685 Allow for specifying boot arguments to the kernel at
1686 build time. On some systems (e.g. embedded ones), it is
1687 necessary or convenient to provide some or all of the
1688 kernel boot arguments with the kernel itself (that is,
1689 to not rely on the boot loader to provide them.)
1691 To compile command line arguments into the kernel,
1692 set this option to 'Y', then fill in the
1693 the boot arguments in CONFIG_CMDLINE.
1695 Systems with fully functional boot loaders (i.e. non-embedded)
1696 should leave this option set to 'N'.
1699 string "Built-in kernel command string"
1700 depends on CMDLINE_BOOL
1703 Enter arguments here that should be compiled into the kernel
1704 image and used at boot time. If the boot loader provides a
1705 command line at boot time, it is appended to this string to
1706 form the full kernel command line, when the system boots.
1708 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1709 change this behavior.
1711 In most cases, the command line (whether built-in or provided
1712 by the boot loader) should specify the device for the root
1715 config CMDLINE_OVERRIDE
1716 bool "Built-in command line overrides boot loader arguments"
1717 depends on CMDLINE_BOOL
1719 Set this option to 'Y' to have the kernel ignore the boot loader
1720 command line, and use ONLY the built-in command line.
1722 This is used to work around broken boot loaders. This should
1723 be set to 'N' under normal conditions.
1727 config ARCH_ENABLE_MEMORY_HOTPLUG
1729 depends on X86_64 || (X86_32 && HIGHMEM)
1731 config ARCH_ENABLE_MEMORY_HOTREMOVE
1733 depends on MEMORY_HOTPLUG
1735 config USE_PERCPU_NUMA_NODE_ID
1739 menu "Power management and ACPI options"
1741 config ARCH_HIBERNATION_HEADER
1743 depends on X86_64 && HIBERNATION
1745 source "kernel/power/Kconfig"
1747 source "drivers/acpi/Kconfig"
1749 source "drivers/sfi/Kconfig"
1753 depends on APM || APM_MODULE
1756 tristate "APM (Advanced Power Management) BIOS support"
1757 depends on X86_32 && PM_SLEEP
1759 APM is a BIOS specification for saving power using several different
1760 techniques. This is mostly useful for battery powered laptops with
1761 APM compliant BIOSes. If you say Y here, the system time will be
1762 reset after a RESUME operation, the /proc/apm device will provide
1763 battery status information, and user-space programs will receive
1764 notification of APM "events" (e.g. battery status change).
1766 If you select "Y" here, you can disable actual use of the APM
1767 BIOS by passing the "apm=off" option to the kernel at boot time.
1769 Note that the APM support is almost completely disabled for
1770 machines with more than one CPU.
1772 In order to use APM, you will need supporting software. For location
1773 and more information, read <file:Documentation/power/apm-acpi.txt>
1774 and the Battery Powered Linux mini-HOWTO, available from
1775 <http://www.tldp.org/docs.html#howto>.
1777 This driver does not spin down disk drives (see the hdparm(8)
1778 manpage ("man 8 hdparm") for that), and it doesn't turn off
1779 VESA-compliant "green" monitors.
1781 This driver does not support the TI 4000M TravelMate and the ACER
1782 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1783 desktop machines also don't have compliant BIOSes, and this driver
1784 may cause those machines to panic during the boot phase.
1786 Generally, if you don't have a battery in your machine, there isn't
1787 much point in using this driver and you should say N. If you get
1788 random kernel OOPSes or reboots that don't seem to be related to
1789 anything, try disabling/enabling this option (or disabling/enabling
1792 Some other things you should try when experiencing seemingly random,
1795 1) make sure that you have enough swap space and that it is
1797 2) pass the "no-hlt" option to the kernel
1798 3) switch on floating point emulation in the kernel and pass
1799 the "no387" option to the kernel
1800 4) pass the "floppy=nodma" option to the kernel
1801 5) pass the "mem=4M" option to the kernel (thereby disabling
1802 all but the first 4 MB of RAM)
1803 6) make sure that the CPU is not over clocked.
1804 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1805 8) disable the cache from your BIOS settings
1806 9) install a fan for the video card or exchange video RAM
1807 10) install a better fan for the CPU
1808 11) exchange RAM chips
1809 12) exchange the motherboard.
1811 To compile this driver as a module, choose M here: the
1812 module will be called apm.
1816 config APM_IGNORE_USER_SUSPEND
1817 bool "Ignore USER SUSPEND"
1819 This option will ignore USER SUSPEND requests. On machines with a
1820 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1821 series notebooks, it is necessary to say Y because of a BIOS bug.
1823 config APM_DO_ENABLE
1824 bool "Enable PM at boot time"
1826 Enable APM features at boot time. From page 36 of the APM BIOS
1827 specification: "When disabled, the APM BIOS does not automatically
1828 power manage devices, enter the Standby State, enter the Suspend
1829 State, or take power saving steps in response to CPU Idle calls."
1830 This driver will make CPU Idle calls when Linux is idle (unless this
1831 feature is turned off -- see "Do CPU IDLE calls", below). This
1832 should always save battery power, but more complicated APM features
1833 will be dependent on your BIOS implementation. You may need to turn
1834 this option off if your computer hangs at boot time when using APM
1835 support, or if it beeps continuously instead of suspending. Turn
1836 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1837 T400CDT. This is off by default since most machines do fine without
1841 bool "Make CPU Idle calls when idle"
1843 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1844 On some machines, this can activate improved power savings, such as
1845 a slowed CPU clock rate, when the machine is idle. These idle calls
1846 are made after the idle loop has run for some length of time (e.g.,
1847 333 mS). On some machines, this will cause a hang at boot time or
1848 whenever the CPU becomes idle. (On machines with more than one CPU,
1849 this option does nothing.)
1851 config APM_DISPLAY_BLANK
1852 bool "Enable console blanking using APM"
1854 Enable console blanking using the APM. Some laptops can use this to
1855 turn off the LCD backlight when the screen blanker of the Linux
1856 virtual console blanks the screen. Note that this is only used by
1857 the virtual console screen blanker, and won't turn off the backlight
1858 when using the X Window system. This also doesn't have anything to
1859 do with your VESA-compliant power-saving monitor. Further, this
1860 option doesn't work for all laptops -- it might not turn off your
1861 backlight at all, or it might print a lot of errors to the console,
1862 especially if you are using gpm.
1864 config APM_ALLOW_INTS
1865 bool "Allow interrupts during APM BIOS calls"
1867 Normally we disable external interrupts while we are making calls to
1868 the APM BIOS as a measure to lessen the effects of a badly behaving
1869 BIOS implementation. The BIOS should reenable interrupts if it
1870 needs to. Unfortunately, some BIOSes do not -- especially those in
1871 many of the newer IBM Thinkpads. If you experience hangs when you
1872 suspend, try setting this to Y. Otherwise, say N.
1876 source "drivers/cpufreq/Kconfig"
1878 source "drivers/cpuidle/Kconfig"
1880 source "drivers/idle/Kconfig"
1885 menu "Bus options (PCI etc.)"
1890 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1892 Find out whether you have a PCI motherboard. PCI is the name of a
1893 bus system, i.e. the way the CPU talks to the other stuff inside
1894 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1895 VESA. If you have PCI, say Y, otherwise N.
1898 prompt "PCI access mode"
1899 depends on X86_32 && PCI
1902 On PCI systems, the BIOS can be used to detect the PCI devices and
1903 determine their configuration. However, some old PCI motherboards
1904 have BIOS bugs and may crash if this is done. Also, some embedded
1905 PCI-based systems don't have any BIOS at all. Linux can also try to
1906 detect the PCI hardware directly without using the BIOS.
1908 With this option, you can specify how Linux should detect the
1909 PCI devices. If you choose "BIOS", the BIOS will be used,
1910 if you choose "Direct", the BIOS won't be used, and if you
1911 choose "MMConfig", then PCI Express MMCONFIG will be used.
1912 If you choose "Any", the kernel will try MMCONFIG, then the
1913 direct access method and falls back to the BIOS if that doesn't
1914 work. If unsure, go with the default, which is "Any".
1919 config PCI_GOMMCONFIG
1936 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1938 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1941 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1945 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1949 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1953 depends on PCI && XEN
1961 bool "Support mmconfig PCI config space access"
1962 depends on X86_64 && PCI && ACPI
1964 config PCI_CNB20LE_QUIRK
1965 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1967 depends on PCI && EXPERIMENTAL
1969 Read the PCI windows out of the CNB20LE host bridge. This allows
1970 PCI hotplug to work on systems with the CNB20LE chipset which do
1973 There's no public spec for this chipset, and this functionality
1974 is known to be incomplete.
1976 You should say N unless you know you need this.
1978 source "drivers/pci/pcie/Kconfig"
1980 source "drivers/pci/Kconfig"
1982 # x86_64 have no ISA slots, but can have ISA-style DMA.
1984 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1987 Enables ISA-style DMA support for devices requiring such controllers.
1995 Find out whether you have ISA slots on your motherboard. ISA is the
1996 name of a bus system, i.e. the way the CPU talks to the other stuff
1997 inside your box. Other bus systems are PCI, EISA, MicroChannel
1998 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1999 newer boards don't support it. If you have ISA, say Y, otherwise N.
2005 The Extended Industry Standard Architecture (EISA) bus was
2006 developed as an open alternative to the IBM MicroChannel bus.
2008 The EISA bus provided some of the features of the IBM MicroChannel
2009 bus while maintaining backward compatibility with cards made for
2010 the older ISA bus. The EISA bus saw limited use between 1988 and
2011 1995 when it was made obsolete by the PCI bus.
2013 Say Y here if you are building a kernel for an EISA-based machine.
2017 source "drivers/eisa/Kconfig"
2022 MicroChannel Architecture is found in some IBM PS/2 machines and
2023 laptops. It is a bus system similar to PCI or ISA. See
2024 <file:Documentation/mca.txt> (and especially the web page given
2025 there) before attempting to build an MCA bus kernel.
2027 source "drivers/mca/Kconfig"
2030 tristate "NatSemi SCx200 support"
2032 This provides basic support for National Semiconductor's
2033 (now AMD's) Geode processors. The driver probes for the
2034 PCI-IDs of several on-chip devices, so its a good dependency
2035 for other scx200_* drivers.
2037 If compiled as a module, the driver is named scx200.
2039 config SCx200HR_TIMER
2040 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2044 This driver provides a clocksource built upon the on-chip
2045 27MHz high-resolution timer. Its also a workaround for
2046 NSC Geode SC-1100's buggy TSC, which loses time when the
2047 processor goes idle (as is done by the scheduler). The
2048 other workaround is idle=poll boot option.
2051 bool "One Laptop Per Child support"
2057 Add support for detecting the unique features of the OLPC
2061 bool "OLPC XO-1 Power Management"
2062 depends on OLPC && MFD_CS5535 && PM_SLEEP
2065 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2068 bool "OLPC XO-1 Real Time Clock"
2069 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2071 Add support for the XO-1 real time clock, which can be used as a
2072 programmable wakeup source.
2075 bool "OLPC XO-1 SCI extras"
2076 depends on OLPC && OLPC_XO1_PM
2081 Add support for SCI-based features of the OLPC XO-1 laptop:
2082 - EC-driven system wakeups
2086 - AC adapter status updates
2087 - Battery status updates
2089 config OLPC_XO15_SCI
2090 bool "OLPC XO-1.5 SCI extras"
2091 depends on OLPC && ACPI
2094 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2095 - EC-driven system wakeups
2096 - AC adapter status updates
2097 - Battery status updates
2100 bool "PCEngines ALIX System Support (LED setup)"
2103 This option enables system support for the PCEngines ALIX.
2104 At present this just sets up LEDs for GPIO control on
2105 ALIX2/3/6 boards. However, other system specific setup should
2108 Note: You must still enable the drivers for GPIO and LED support
2109 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2111 Note: You have to set alix.force=1 for boards with Award BIOS.
2117 depends on CPU_SUP_AMD && PCI
2119 source "drivers/pcmcia/Kconfig"
2121 source "drivers/pci/hotplug/Kconfig"
2124 bool "RapidIO support"
2128 If you say Y here, the kernel will include drivers and
2129 infrastructure code to support RapidIO interconnect devices.
2131 source "drivers/rapidio/Kconfig"
2136 menu "Executable file formats / Emulations"
2138 source "fs/Kconfig.binfmt"
2140 config IA32_EMULATION
2141 bool "IA32 Emulation"
2144 select COMPAT_BINFMT_ELF
2146 Include code to run 32-bit programs under a 64-bit kernel. You should
2147 likely turn this on, unless you're 100% sure that you don't have any
2148 32-bit programs left.
2151 tristate "IA32 a.out support"
2152 depends on IA32_EMULATION
2154 Support old a.out binaries in the 32bit emulation.
2158 depends on IA32_EMULATION
2160 config COMPAT_FOR_U64_ALIGNMENT
2164 config SYSVIPC_COMPAT
2166 depends on COMPAT && SYSVIPC
2170 depends on COMPAT && KEYS
2176 config HAVE_ATOMIC_IOMAP
2180 config HAVE_TEXT_POKE_SMP
2182 select STOP_MACHINE if SMP
2184 source "net/Kconfig"
2186 source "drivers/Kconfig"
2188 source "drivers/firmware/Kconfig"
2192 source "arch/x86/Kconfig.debug"
2194 source "security/Kconfig"
2196 source "crypto/Kconfig"
2198 source "arch/x86/kvm/Kconfig"
2200 source "lib/Kconfig"