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 HAVE_MEMBLOCK_NODE_MAP
30 select ARCH_DISCARD_MEMBLOCK
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_C_RECORDMCOUNT
38 select HAVE_DYNAMIC_FTRACE
39 select HAVE_FUNCTION_TRACER
40 select HAVE_FUNCTION_GRAPH_TRACER
41 select HAVE_FUNCTION_GRAPH_FP_TEST
42 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
43 select HAVE_SYSCALL_TRACEPOINTS
46 select HAVE_ARCH_TRACEHOOK
47 select HAVE_GENERIC_DMA_COHERENT if X86_32
48 select HAVE_EFFICIENT_UNALIGNED_ACCESS
49 select USER_STACKTRACE_SUPPORT
50 select HAVE_REGS_AND_STACK_ACCESS_API
51 select HAVE_DMA_API_DEBUG
52 select HAVE_KERNEL_GZIP
53 select HAVE_KERNEL_BZIP2
54 select HAVE_KERNEL_LZMA
56 select HAVE_KERNEL_LZO
57 select HAVE_HW_BREAKPOINT
58 select HAVE_MIXED_BREAKPOINTS_REGS
60 select HAVE_PERF_EVENTS_NMI
62 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
63 select HAVE_CMPXCHG_LOCAL if !M386
64 select HAVE_CMPXCHG_DOUBLE
65 select HAVE_ARCH_KMEMCHECK
66 select HAVE_USER_RETURN_NOTIFIER
67 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
68 select HAVE_ARCH_JUMP_LABEL
69 select HAVE_TEXT_POKE_SMP
70 select HAVE_GENERIC_HARDIRQS
72 select GENERIC_FIND_FIRST_BIT
73 select GENERIC_IRQ_PROBE
74 select GENERIC_PENDING_IRQ if SMP
75 select GENERIC_IRQ_SHOW
76 select GENERIC_CLOCKEVENTS_MIN_ADJUST
77 select IRQ_FORCED_THREADING
78 select USE_GENERIC_SMP_HELPERS if SMP
79 select HAVE_BPF_JIT if (X86_64 && NET)
81 select ARCH_HAVE_NMI_SAFE_CMPXCHG
83 select DCACHE_WORD_ACCESS if !DEBUG_PAGEALLOC
85 config INSTRUCTION_DECODER
86 def_bool (KPROBES || PERF_EVENTS || UPROBES)
90 default "elf32-i386" if X86_32
91 default "elf64-x86-64" if X86_64
95 default "arch/x86/configs/i386_defconfig" if X86_32
96 default "arch/x86/configs/x86_64_defconfig" if X86_64
98 config GENERIC_CMOS_UPDATE
101 config CLOCKSOURCE_WATCHDOG
104 config GENERIC_CLOCKEVENTS
107 config ARCH_CLOCKSOURCE_DATA
111 config GENERIC_CLOCKEVENTS_BROADCAST
113 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
115 config LOCKDEP_SUPPORT
118 config STACKTRACE_SUPPORT
121 config HAVE_LATENCYTOP_SUPPORT
130 config NEED_DMA_MAP_STATE
131 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
133 config NEED_SG_DMA_LENGTH
136 config GENERIC_ISA_DMA
142 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
144 config GENERIC_BUG_RELATIVE_POINTERS
147 config GENERIC_HWEIGHT
153 config ARCH_MAY_HAVE_PC_FDC
156 config RWSEM_GENERIC_SPINLOCK
159 config RWSEM_XCHGADD_ALGORITHM
162 config ARCH_HAS_CPU_IDLE_WAIT
165 config GENERIC_CALIBRATE_DELAY
168 config GENERIC_TIME_VSYSCALL
172 config ARCH_HAS_CPU_RELAX
175 config ARCH_HAS_DEFAULT_IDLE
178 config ARCH_HAS_CACHE_LINE_SIZE
181 config ARCH_HAS_CPU_AUTOPROBE
184 config HAVE_SETUP_PER_CPU_AREA
187 config NEED_PER_CPU_EMBED_FIRST_CHUNK
190 config NEED_PER_CPU_PAGE_FIRST_CHUNK
193 config ARCH_HIBERNATION_POSSIBLE
196 config ARCH_SUSPEND_POSSIBLE
207 config ARCH_SUPPORTS_OPTIMIZED_INLINING
210 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
213 config HAVE_INTEL_TXT
215 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
219 depends on X86_32 && SMP
223 depends on X86_64 && SMP
229 config X86_32_LAZY_GS
231 depends on X86_32 && !CC_STACKPROTECTOR
233 config ARCH_HWEIGHT_CFLAGS
235 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
236 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
241 config ARCH_CPU_PROBE_RELEASE
243 depends on HOTPLUG_CPU
245 config ARCH_SUPPORTS_UPROBES
248 source "init/Kconfig"
249 source "kernel/Kconfig.freezer"
251 menu "Processor type and features"
254 bool "DMA memory allocation support" if EXPERT
257 DMA memory allocation support allows devices with less than 32-bit
258 addressing to allocate within the first 16MB of address space.
259 Disable if no such devices will be used.
263 source "kernel/time/Kconfig"
266 bool "Symmetric multi-processing support"
268 This enables support for systems with more than one CPU. If you have
269 a system with only one CPU, like most personal computers, say N. If
270 you have a system with more than one CPU, say Y.
272 If you say N here, the kernel will run on single and multiprocessor
273 machines, but will use only one CPU of a multiprocessor machine. If
274 you say Y here, the kernel will run on many, but not all,
275 singleprocessor machines. On a singleprocessor machine, the kernel
276 will run faster if you say N here.
278 Note that if you say Y here and choose architecture "586" or
279 "Pentium" under "Processor family", the kernel will not work on 486
280 architectures. Similarly, multiprocessor kernels for the "PPro"
281 architecture may not work on all Pentium based boards.
283 People using multiprocessor machines who say Y here should also say
284 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
285 Management" code will be disabled if you say Y here.
287 See also <file:Documentation/x86/i386/IO-APIC.txt>,
288 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
289 <http://www.tldp.org/docs.html#howto>.
291 If you don't know what to do here, say N.
294 bool "Support x2apic"
295 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
297 This enables x2apic support on CPUs that have this feature.
299 This allows 32-bit apic IDs (so it can support very large systems),
300 and accesses the local apic via MSRs not via mmio.
302 If you don't know what to do here, say N.
305 bool "Enable MPS table" if ACPI
307 depends on X86_LOCAL_APIC
309 For old smp systems that do not have proper acpi support. Newer systems
310 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
313 bool "Support for big SMP systems with more than 8 CPUs"
314 depends on X86_32 && SMP
316 This option is needed for the systems that have more than 8 CPUs
319 config X86_EXTENDED_PLATFORM
320 bool "Support for extended (non-PC) x86 platforms"
323 If you disable this option then the kernel will only support
324 standard PC platforms. (which covers the vast majority of
327 If you enable this option then you'll be able to select support
328 for the following (non-PC) 32 bit x86 platforms:
332 SGI 320/540 (Visual Workstation)
333 Summit/EXA (IBM x440)
334 Unisys ES7000 IA32 series
335 Moorestown MID devices
337 If you have one of these systems, or if you want to build a
338 generic distribution kernel, say Y here - otherwise say N.
342 config X86_EXTENDED_PLATFORM
343 bool "Support for extended (non-PC) x86 platforms"
346 If you disable this option then the kernel will only support
347 standard PC platforms. (which covers the vast majority of
350 If you enable this option then you'll be able to select support
351 for the following (non-PC) 64 bit x86 platforms:
356 If you have one of these systems, or if you want to build a
357 generic distribution kernel, say Y here - otherwise say N.
359 # This is an alphabetically sorted list of 64 bit extended platforms
360 # Please maintain the alphabetic order if and when there are additions
362 bool "Numascale NumaChip"
364 depends on X86_EXTENDED_PLATFORM
367 depends on X86_X2APIC
369 Adds support for Numascale NumaChip large-SMP systems. Needed to
370 enable more than ~168 cores.
371 If you don't have one of these, you should say N here.
375 select PARAVIRT_GUEST
377 depends on X86_64 && PCI
378 depends on X86_EXTENDED_PLATFORM
380 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
381 supposed to run on these EM64T-based machines. Only choose this option
382 if you have one of these machines.
385 bool "SGI Ultraviolet"
387 depends on X86_EXTENDED_PLATFORM
389 depends on X86_X2APIC
391 This option is needed in order to support SGI Ultraviolet systems.
392 If you don't have one of these, you should say N here.
394 # Following is an alphabetically sorted list of 32 bit extended platforms
395 # Please maintain the alphabetic order if and when there are additions
398 bool "CE4100 TV platform"
400 depends on PCI_GODIRECT
402 depends on X86_EXTENDED_PLATFORM
403 select X86_REBOOTFIXUPS
405 select OF_EARLY_FLATTREE
408 Select for the Intel CE media processor (CE4100) SOC.
409 This option compiles in support for the CE4100 SOC for settop
410 boxes and media devices.
412 config X86_WANT_INTEL_MID
413 bool "Intel MID platform support"
415 depends on X86_EXTENDED_PLATFORM
417 Select to build a kernel capable of supporting Intel MID platform
418 systems which do not have the PCI legacy interfaces (Moorestown,
419 Medfield). If you are building for a PC class system say N here.
421 if X86_WANT_INTEL_MID
427 bool "Medfield MID platform"
430 depends on X86_IO_APIC
438 select X86_PLATFORM_DEVICES
439 select MFD_INTEL_MSIC
441 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
442 Internet Device(MID) platform.
443 Unlike standard x86 PCs, Medfield does not have many legacy devices
444 nor standard legacy replacement devices/features. e.g. Medfield does
445 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
450 bool "RDC R-321x SoC"
452 depends on X86_EXTENDED_PLATFORM
454 select X86_REBOOTFIXUPS
456 This option is needed for RDC R-321x system-on-chip, also known
458 If you don't have one of these chips, you should say N here.
460 config X86_32_NON_STANDARD
461 bool "Support non-standard 32-bit SMP architectures"
462 depends on X86_32 && SMP
463 depends on X86_EXTENDED_PLATFORM
465 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
466 subarchitectures. It is intended for a generic binary kernel.
467 if you select them all, kernel will probe it one by one. and will
470 # Alphabetically sorted list of Non standard 32 bit platforms
473 bool "NUMAQ (IBM/Sequent)"
474 depends on X86_32_NON_STANDARD
479 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
480 NUMA multiquad box. This changes the way that processors are
481 bootstrapped, and uses Clustered Logical APIC addressing mode instead
482 of Flat Logical. You will need a new lynxer.elf file to flash your
483 firmware with - send email to <Martin.Bligh@us.ibm.com>.
485 config X86_SUPPORTS_MEMORY_FAILURE
487 # MCE code calls memory_failure():
489 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
490 depends on !X86_NUMAQ
491 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
492 depends on X86_64 || !SPARSEMEM
493 select ARCH_SUPPORTS_MEMORY_FAILURE
496 bool "SGI 320/540 (Visual Workstation)"
497 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
498 depends on X86_32_NON_STANDARD
500 The SGI Visual Workstation series is an IA32-based workstation
501 based on SGI systems chips with some legacy PC hardware attached.
503 Say Y here to create a kernel to run on the SGI 320 or 540.
505 A kernel compiled for the Visual Workstation will run on general
506 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
509 bool "Summit/EXA (IBM x440)"
510 depends on X86_32_NON_STANDARD
512 This option is needed for IBM systems that use the Summit/EXA chipset.
513 In particular, it is needed for the x440.
516 bool "Unisys ES7000 IA32 series"
517 depends on X86_32_NON_STANDARD && X86_BIGSMP
519 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
520 supposed to run on an IA32-based Unisys ES7000 system.
523 tristate "Eurobraille/Iris poweroff module"
526 The Iris machines from EuroBraille do not have APM or ACPI support
527 to shut themselves down properly. A special I/O sequence is
528 needed to do so, which is what this module does at
531 This is only for Iris machines from EuroBraille.
535 config SCHED_OMIT_FRAME_POINTER
537 prompt "Single-depth WCHAN output"
540 Calculate simpler /proc/<PID>/wchan values. If this option
541 is disabled then wchan values will recurse back to the
542 caller function. This provides more accurate wchan values,
543 at the expense of slightly more scheduling overhead.
545 If in doubt, say "Y".
547 menuconfig PARAVIRT_GUEST
548 bool "Paravirtualized guest support"
550 Say Y here to get to see options related to running Linux under
551 various hypervisors. This option alone does not add any kernel code.
553 If you say N, all options in this submenu will be skipped and disabled.
557 config PARAVIRT_TIME_ACCOUNTING
558 bool "Paravirtual steal time accounting"
562 Select this option to enable fine granularity task steal time
563 accounting. Time spent executing other tasks in parallel with
564 the current vCPU is discounted from the vCPU power. To account for
565 that, there can be a small performance impact.
567 If in doubt, say N here.
569 source "arch/x86/xen/Kconfig"
572 bool "KVM paravirtualized clock"
574 select PARAVIRT_CLOCK
576 Turning on this option will allow you to run a paravirtualized clock
577 when running over the KVM hypervisor. Instead of relying on a PIT
578 (or probably other) emulation by the underlying device model, the host
579 provides the guest with timing infrastructure such as time of day, and
583 bool "KVM Guest support"
586 This option enables various optimizations for running under the KVM
589 source "arch/x86/lguest/Kconfig"
592 bool "Enable paravirtualization code"
594 This changes the kernel so it can modify itself when it is run
595 under a hypervisor, potentially improving performance significantly
596 over full virtualization. However, when run without a hypervisor
597 the kernel is theoretically slower and slightly larger.
599 config PARAVIRT_SPINLOCKS
600 bool "Paravirtualization layer for spinlocks"
601 depends on PARAVIRT && SMP && EXPERIMENTAL
603 Paravirtualized spinlocks allow a pvops backend to replace the
604 spinlock implementation with something virtualization-friendly
605 (for example, block the virtual CPU rather than spinning).
607 Unfortunately the downside is an up to 5% performance hit on
608 native kernels, with various workloads.
610 If you are unsure how to answer this question, answer N.
612 config PARAVIRT_CLOCK
617 config PARAVIRT_DEBUG
618 bool "paravirt-ops debugging"
619 depends on PARAVIRT && DEBUG_KERNEL
621 Enable to debug paravirt_ops internals. Specifically, BUG if
622 a paravirt_op is missing when it is called.
630 This option adds a kernel parameter 'memtest', which allows memtest
632 memtest=0, mean disabled; -- default
633 memtest=1, mean do 1 test pattern;
635 memtest=4, mean do 4 test patterns.
636 If you are unsure how to answer this question, answer N.
638 config X86_SUMMIT_NUMA
640 depends on X86_32 && NUMA && X86_32_NON_STANDARD
642 config X86_CYCLONE_TIMER
644 depends on X86_SUMMIT
646 source "arch/x86/Kconfig.cpu"
650 prompt "HPET Timer Support" if X86_32
652 Use the IA-PC HPET (High Precision Event Timer) to manage
653 time in preference to the PIT and RTC, if a HPET is
655 HPET is the next generation timer replacing legacy 8254s.
656 The HPET provides a stable time base on SMP
657 systems, unlike the TSC, but it is more expensive to access,
658 as it is off-chip. You can find the HPET spec at
659 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
661 You can safely choose Y here. However, HPET will only be
662 activated if the platform and the BIOS support this feature.
663 Otherwise the 8254 will be used for timing services.
665 Choose N to continue using the legacy 8254 timer.
667 config HPET_EMULATE_RTC
669 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
672 def_bool y if X86_INTEL_MID
673 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
675 depends on X86_INTEL_MID && SFI
677 APB timer is the replacement for 8254, HPET on X86 MID platforms.
678 The APBT provides a stable time base on SMP
679 systems, unlike the TSC, but it is more expensive to access,
680 as it is off-chip. APB timers are always running regardless of CPU
681 C states, they are used as per CPU clockevent device when possible.
683 # Mark as expert because too many people got it wrong.
684 # The code disables itself when not needed.
687 bool "Enable DMI scanning" if EXPERT
689 Enabled scanning of DMI to identify machine quirks. Say Y
690 here unless you have verified that your setup is not
691 affected by entries in the DMI blacklist. Required by PNP
695 bool "GART IOMMU support" if EXPERT
698 depends on X86_64 && PCI && AMD_NB
700 Support for full DMA access of devices with 32bit memory access only
701 on systems with more than 3GB. This is usually needed for USB,
702 sound, many IDE/SATA chipsets and some other devices.
703 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
704 based hardware IOMMU and a software bounce buffer based IOMMU used
705 on Intel systems and as fallback.
706 The code is only active when needed (enough memory and limited
707 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
711 bool "IBM Calgary IOMMU support"
713 depends on X86_64 && PCI && EXPERIMENTAL
715 Support for hardware IOMMUs in IBM's xSeries x366 and x460
716 systems. Needed to run systems with more than 3GB of memory
717 properly with 32-bit PCI devices that do not support DAC
718 (Double Address Cycle). Calgary also supports bus level
719 isolation, where all DMAs pass through the IOMMU. This
720 prevents them from going anywhere except their intended
721 destination. This catches hard-to-find kernel bugs and
722 mis-behaving drivers and devices that do not use the DMA-API
723 properly to set up their DMA buffers. The IOMMU can be
724 turned off at boot time with the iommu=off parameter.
725 Normally the kernel will make the right choice by itself.
728 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
730 prompt "Should Calgary be enabled by default?"
731 depends on CALGARY_IOMMU
733 Should Calgary be enabled by default? if you choose 'y', Calgary
734 will be used (if it exists). If you choose 'n', Calgary will not be
735 used even if it exists. If you choose 'n' and would like to use
736 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
739 # need this always selected by IOMMU for the VIA workaround
743 Support for software bounce buffers used on x86-64 systems
744 which don't have a hardware IOMMU (e.g. the current generation
745 of Intel's x86-64 CPUs). Using this PCI devices which can only
746 access 32-bits of memory can be used on systems with more than
747 3 GB of memory. If unsure, say Y.
750 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
753 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
754 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
755 select CPUMASK_OFFSTACK
757 Enable maximum number of CPUS and NUMA Nodes for this architecture.
761 int "Maximum number of CPUs" if SMP && !MAXSMP
762 range 2 8 if SMP && X86_32 && !X86_BIGSMP
763 range 2 512 if SMP && !MAXSMP
765 default "4096" if MAXSMP
766 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
769 This allows you to specify the maximum number of CPUs which this
770 kernel will support. The maximum supported value is 512 and the
771 minimum value which makes sense is 2.
773 This is purely to save memory - each supported CPU adds
774 approximately eight kilobytes to the kernel image.
777 bool "SMT (Hyperthreading) scheduler support"
780 SMT scheduler support improves the CPU scheduler's decision making
781 when dealing with Intel Pentium 4 chips with HyperThreading at a
782 cost of slightly increased overhead in some places. If unsure say
787 prompt "Multi-core scheduler support"
790 Multi-core scheduler support improves the CPU scheduler's decision
791 making when dealing with multi-core CPU chips at a cost of slightly
792 increased overhead in some places. If unsure say N here.
794 config IRQ_TIME_ACCOUNTING
795 bool "Fine granularity task level IRQ time accounting"
798 Select this option to enable fine granularity task irq time
799 accounting. This is done by reading a timestamp on each
800 transitions between softirq and hardirq state, so there can be a
801 small performance impact.
803 If in doubt, say N here.
805 source "kernel/Kconfig.preempt"
808 bool "Local APIC support on uniprocessors"
809 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
811 A local APIC (Advanced Programmable Interrupt Controller) is an
812 integrated interrupt controller in the CPU. If you have a single-CPU
813 system which has a processor with a local APIC, you can say Y here to
814 enable and use it. If you say Y here even though your machine doesn't
815 have a local APIC, then the kernel will still run with no slowdown at
816 all. The local APIC supports CPU-generated self-interrupts (timer,
817 performance counters), and the NMI watchdog which detects hard
821 bool "IO-APIC support on uniprocessors"
822 depends on X86_UP_APIC
824 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
825 SMP-capable replacement for PC-style interrupt controllers. Most
826 SMP systems and many recent uniprocessor systems have one.
828 If you have a single-CPU system with an IO-APIC, you can say Y here
829 to use it. If you say Y here even though your machine doesn't have
830 an IO-APIC, then the kernel will still run with no slowdown at all.
832 config X86_LOCAL_APIC
834 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
838 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
840 config X86_VISWS_APIC
842 depends on X86_32 && X86_VISWS
844 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
845 bool "Reroute for broken boot IRQs"
846 depends on X86_IO_APIC
848 This option enables a workaround that fixes a source of
849 spurious interrupts. This is recommended when threaded
850 interrupt handling is used on systems where the generation of
851 superfluous "boot interrupts" cannot be disabled.
853 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
854 entry in the chipset's IO-APIC is masked (as, e.g. the RT
855 kernel does during interrupt handling). On chipsets where this
856 boot IRQ generation cannot be disabled, this workaround keeps
857 the original IRQ line masked so that only the equivalent "boot
858 IRQ" is delivered to the CPUs. The workaround also tells the
859 kernel to set up the IRQ handler on the boot IRQ line. In this
860 way only one interrupt is delivered to the kernel. Otherwise
861 the spurious second interrupt may cause the kernel to bring
862 down (vital) interrupt lines.
864 Only affects "broken" chipsets. Interrupt sharing may be
865 increased on these systems.
868 bool "Machine Check / overheating reporting"
870 Machine Check support allows the processor to notify the
871 kernel if it detects a problem (e.g. overheating, data corruption).
872 The action the kernel takes depends on the severity of the problem,
873 ranging from warning messages to halting the machine.
877 prompt "Intel MCE features"
878 depends on X86_MCE && X86_LOCAL_APIC
880 Additional support for intel specific MCE features such as
885 prompt "AMD MCE features"
886 depends on X86_MCE && X86_LOCAL_APIC
888 Additional support for AMD specific MCE features such as
889 the DRAM Error Threshold.
891 config X86_ANCIENT_MCE
892 bool "Support for old Pentium 5 / WinChip machine checks"
893 depends on X86_32 && X86_MCE
895 Include support for machine check handling on old Pentium 5 or WinChip
896 systems. These typically need to be enabled explicitely on the command
899 config X86_MCE_THRESHOLD
900 depends on X86_MCE_AMD || X86_MCE_INTEL
903 config X86_MCE_INJECT
905 tristate "Machine check injector support"
907 Provide support for injecting machine checks for testing purposes.
908 If you don't know what a machine check is and you don't do kernel
909 QA it is safe to say n.
911 config X86_THERMAL_VECTOR
913 depends on X86_MCE_INTEL
916 bool "Enable VM86 support" if EXPERT
920 This option is required by programs like DOSEMU to run 16-bit legacy
921 code on X86 processors. It also may be needed by software like
922 XFree86 to initialize some video cards via BIOS. Disabling this
923 option saves about 6k.
926 tristate "Toshiba Laptop support"
929 This adds a driver to safely access the System Management Mode of
930 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
931 not work on models with a Phoenix BIOS. The System Management Mode
932 is used to set the BIOS and power saving options on Toshiba portables.
934 For information on utilities to make use of this driver see the
935 Toshiba Linux utilities web site at:
936 <http://www.buzzard.org.uk/toshiba/>.
938 Say Y if you intend to run this kernel on a Toshiba portable.
942 tristate "Dell laptop support"
945 This adds a driver to safely access the System Management Mode
946 of the CPU on the Dell Inspiron 8000. The System Management Mode
947 is used to read cpu temperature and cooling fan status and to
948 control the fans on the I8K portables.
950 This driver has been tested only on the Inspiron 8000 but it may
951 also work with other Dell laptops. You can force loading on other
952 models by passing the parameter `force=1' to the module. Use at
955 For information on utilities to make use of this driver see the
956 I8K Linux utilities web site at:
957 <http://people.debian.org/~dz/i8k/>
959 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
962 config X86_REBOOTFIXUPS
963 bool "Enable X86 board specific fixups for reboot"
966 This enables chipset and/or board specific fixups to be done
967 in order to get reboot to work correctly. This is only needed on
968 some combinations of hardware and BIOS. The symptom, for which
969 this config is intended, is when reboot ends with a stalled/hung
972 Currently, the only fixup is for the Geode machines using
973 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
975 Say Y if you want to enable the fixup. Currently, it's safe to
976 enable this option even if you don't need it.
980 tristate "/dev/cpu/microcode - microcode support"
983 If you say Y here, you will be able to update the microcode on
984 certain Intel and AMD processors. The Intel support is for the
985 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
986 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
987 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
988 You will obviously need the actual microcode binary data itself
989 which is not shipped with the Linux kernel.
991 This option selects the general module only, you need to select
992 at least one vendor specific module as well.
994 To compile this driver as a module, choose M here: the
995 module will be called microcode.
997 config MICROCODE_INTEL
998 bool "Intel microcode patch loading support"
1003 This options enables microcode patch loading support for Intel
1006 For latest news and information on obtaining all the required
1007 Intel ingredients for this driver, check:
1008 <http://www.urbanmyth.org/microcode/>.
1010 config MICROCODE_AMD
1011 bool "AMD microcode patch loading support"
1012 depends on MICROCODE
1015 If you select this option, microcode patch loading support for AMD
1016 processors will be enabled.
1018 config MICROCODE_OLD_INTERFACE
1020 depends on MICROCODE
1023 tristate "/dev/cpu/*/msr - Model-specific register support"
1025 This device gives privileged processes access to the x86
1026 Model-Specific Registers (MSRs). It is a character device with
1027 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1028 MSR accesses are directed to a specific CPU on multi-processor
1032 tristate "/dev/cpu/*/cpuid - CPU information support"
1034 This device gives processes access to the x86 CPUID instruction to
1035 be executed on a specific processor. It is a character device
1036 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1040 prompt "High Memory Support"
1041 default HIGHMEM64G if X86_NUMAQ
1047 depends on !X86_NUMAQ
1049 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1050 However, the address space of 32-bit x86 processors is only 4
1051 Gigabytes large. That means that, if you have a large amount of
1052 physical memory, not all of it can be "permanently mapped" by the
1053 kernel. The physical memory that's not permanently mapped is called
1056 If you are compiling a kernel which will never run on a machine with
1057 more than 1 Gigabyte total physical RAM, answer "off" here (default
1058 choice and suitable for most users). This will result in a "3GB/1GB"
1059 split: 3GB are mapped so that each process sees a 3GB virtual memory
1060 space and the remaining part of the 4GB virtual memory space is used
1061 by the kernel to permanently map as much physical memory as
1064 If the machine has between 1 and 4 Gigabytes physical RAM, then
1067 If more than 4 Gigabytes is used then answer "64GB" here. This
1068 selection turns Intel PAE (Physical Address Extension) mode on.
1069 PAE implements 3-level paging on IA32 processors. PAE is fully
1070 supported by Linux, PAE mode is implemented on all recent Intel
1071 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1072 then the kernel will not boot on CPUs that don't support PAE!
1074 The actual amount of total physical memory will either be
1075 auto detected or can be forced by using a kernel command line option
1076 such as "mem=256M". (Try "man bootparam" or see the documentation of
1077 your boot loader (lilo or loadlin) about how to pass options to the
1078 kernel at boot time.)
1080 If unsure, say "off".
1084 depends on !X86_NUMAQ
1086 Select this if you have a 32-bit processor and between 1 and 4
1087 gigabytes of physical RAM.
1091 depends on !M386 && !M486
1094 Select this if you have a 32-bit processor and more than 4
1095 gigabytes of physical RAM.
1100 depends on EXPERIMENTAL
1101 prompt "Memory split" if EXPERT
1105 Select the desired split between kernel and user memory.
1107 If the address range available to the kernel is less than the
1108 physical memory installed, the remaining memory will be available
1109 as "high memory". Accessing high memory is a little more costly
1110 than low memory, as it needs to be mapped into the kernel first.
1111 Note that increasing the kernel address space limits the range
1112 available to user programs, making the address space there
1113 tighter. Selecting anything other than the default 3G/1G split
1114 will also likely make your kernel incompatible with binary-only
1117 If you are not absolutely sure what you are doing, leave this
1121 bool "3G/1G user/kernel split"
1122 config VMSPLIT_3G_OPT
1124 bool "3G/1G user/kernel split (for full 1G low memory)"
1126 bool "2G/2G user/kernel split"
1127 config VMSPLIT_2G_OPT
1129 bool "2G/2G user/kernel split (for full 2G low memory)"
1131 bool "1G/3G user/kernel split"
1136 default 0xB0000000 if VMSPLIT_3G_OPT
1137 default 0x80000000 if VMSPLIT_2G
1138 default 0x78000000 if VMSPLIT_2G_OPT
1139 default 0x40000000 if VMSPLIT_1G
1145 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1148 bool "PAE (Physical Address Extension) Support"
1149 depends on X86_32 && !HIGHMEM4G
1151 PAE is required for NX support, and furthermore enables
1152 larger swapspace support for non-overcommit purposes. It
1153 has the cost of more pagetable lookup overhead, and also
1154 consumes more pagetable space per process.
1156 config ARCH_PHYS_ADDR_T_64BIT
1157 def_bool X86_64 || X86_PAE
1159 config ARCH_DMA_ADDR_T_64BIT
1160 def_bool X86_64 || HIGHMEM64G
1162 config DIRECT_GBPAGES
1163 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1167 Allow the kernel linear mapping to use 1GB pages on CPUs that
1168 support it. This can improve the kernel's performance a tiny bit by
1169 reducing TLB pressure. If in doubt, say "Y".
1171 # Common NUMA Features
1173 bool "Numa Memory Allocation and Scheduler Support"
1175 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1176 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1178 Enable NUMA (Non Uniform Memory Access) support.
1180 The kernel will try to allocate memory used by a CPU on the
1181 local memory controller of the CPU and add some more
1182 NUMA awareness to the kernel.
1184 For 64-bit this is recommended if the system is Intel Core i7
1185 (or later), AMD Opteron, or EM64T NUMA.
1187 For 32-bit this is only needed on (rare) 32-bit-only platforms
1188 that support NUMA topologies, such as NUMAQ / Summit, or if you
1189 boot a 32-bit kernel on a 64-bit NUMA platform.
1191 Otherwise, you should say N.
1193 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1194 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1198 prompt "Old style AMD Opteron NUMA detection"
1199 depends on X86_64 && NUMA && PCI
1201 Enable AMD NUMA node topology detection. You should say Y here if
1202 you have a multi processor AMD system. This uses an old method to
1203 read the NUMA configuration directly from the builtin Northbridge
1204 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1205 which also takes priority if both are compiled in.
1207 config X86_64_ACPI_NUMA
1209 prompt "ACPI NUMA detection"
1210 depends on X86_64 && NUMA && ACPI && PCI
1213 Enable ACPI SRAT based node topology detection.
1215 # Some NUMA nodes have memory ranges that span
1216 # other nodes. Even though a pfn is valid and
1217 # between a node's start and end pfns, it may not
1218 # reside on that node. See memmap_init_zone()
1220 config NODES_SPAN_OTHER_NODES
1222 depends on X86_64_ACPI_NUMA
1225 bool "NUMA emulation"
1228 Enable NUMA emulation. A flat machine will be split
1229 into virtual nodes when booted with "numa=fake=N", where N is the
1230 number of nodes. This is only useful for debugging.
1233 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1235 default "10" if MAXSMP
1236 default "6" if X86_64
1237 default "4" if X86_NUMAQ
1239 depends on NEED_MULTIPLE_NODES
1241 Specify the maximum number of NUMA Nodes available on the target
1242 system. Increases memory reserved to accommodate various tables.
1244 config HAVE_ARCH_BOOTMEM
1246 depends on X86_32 && NUMA
1248 config HAVE_ARCH_ALLOC_REMAP
1250 depends on X86_32 && NUMA
1252 config ARCH_HAVE_MEMORY_PRESENT
1254 depends on X86_32 && DISCONTIGMEM
1256 config NEED_NODE_MEMMAP_SIZE
1258 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1260 config ARCH_FLATMEM_ENABLE
1262 depends on X86_32 && !NUMA
1264 config ARCH_DISCONTIGMEM_ENABLE
1266 depends on NUMA && X86_32
1268 config ARCH_DISCONTIGMEM_DEFAULT
1270 depends on NUMA && X86_32
1272 config ARCH_SPARSEMEM_ENABLE
1274 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1275 select SPARSEMEM_STATIC if X86_32
1276 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1278 config ARCH_SPARSEMEM_DEFAULT
1282 config ARCH_SELECT_MEMORY_MODEL
1284 depends on ARCH_SPARSEMEM_ENABLE
1286 config ARCH_MEMORY_PROBE
1288 depends on MEMORY_HOTPLUG
1290 config ARCH_PROC_KCORE_TEXT
1292 depends on X86_64 && PROC_KCORE
1294 config ILLEGAL_POINTER_VALUE
1297 default 0xdead000000000000 if X86_64
1302 bool "Allocate 3rd-level pagetables from highmem"
1305 The VM uses one page table entry for each page of physical memory.
1306 For systems with a lot of RAM, this can be wasteful of precious
1307 low memory. Setting this option will put user-space page table
1308 entries in high memory.
1310 config X86_CHECK_BIOS_CORRUPTION
1311 bool "Check for low memory corruption"
1313 Periodically check for memory corruption in low memory, which
1314 is suspected to be caused by BIOS. Even when enabled in the
1315 configuration, it is disabled at runtime. Enable it by
1316 setting "memory_corruption_check=1" on the kernel command
1317 line. By default it scans the low 64k of memory every 60
1318 seconds; see the memory_corruption_check_size and
1319 memory_corruption_check_period parameters in
1320 Documentation/kernel-parameters.txt to adjust this.
1322 When enabled with the default parameters, this option has
1323 almost no overhead, as it reserves a relatively small amount
1324 of memory and scans it infrequently. It both detects corruption
1325 and prevents it from affecting the running system.
1327 It is, however, intended as a diagnostic tool; if repeatable
1328 BIOS-originated corruption always affects the same memory,
1329 you can use memmap= to prevent the kernel from using that
1332 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1333 bool "Set the default setting of memory_corruption_check"
1334 depends on X86_CHECK_BIOS_CORRUPTION
1337 Set whether the default state of memory_corruption_check is
1340 config X86_RESERVE_LOW
1341 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1345 Specify the amount of low memory to reserve for the BIOS.
1347 The first page contains BIOS data structures that the kernel
1348 must not use, so that page must always be reserved.
1350 By default we reserve the first 64K of physical RAM, as a
1351 number of BIOSes are known to corrupt that memory range
1352 during events such as suspend/resume or monitor cable
1353 insertion, so it must not be used by the kernel.
1355 You can set this to 4 if you are absolutely sure that you
1356 trust the BIOS to get all its memory reservations and usages
1357 right. If you know your BIOS have problems beyond the
1358 default 64K area, you can set this to 640 to avoid using the
1359 entire low memory range.
1361 If you have doubts about the BIOS (e.g. suspend/resume does
1362 not work or there's kernel crashes after certain hardware
1363 hotplug events) then you might want to enable
1364 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1365 typical corruption patterns.
1367 Leave this to the default value of 64 if you are unsure.
1369 config MATH_EMULATION
1371 prompt "Math emulation" if X86_32
1373 Linux can emulate a math coprocessor (used for floating point
1374 operations) if you don't have one. 486DX and Pentium processors have
1375 a math coprocessor built in, 486SX and 386 do not, unless you added
1376 a 487DX or 387, respectively. (The messages during boot time can
1377 give you some hints here ["man dmesg"].) Everyone needs either a
1378 coprocessor or this emulation.
1380 If you don't have a math coprocessor, you need to say Y here; if you
1381 say Y here even though you have a coprocessor, the coprocessor will
1382 be used nevertheless. (This behavior can be changed with the kernel
1383 command line option "no387", which comes handy if your coprocessor
1384 is broken. Try "man bootparam" or see the documentation of your boot
1385 loader (lilo or loadlin) about how to pass options to the kernel at
1386 boot time.) This means that it is a good idea to say Y here if you
1387 intend to use this kernel on different machines.
1389 More information about the internals of the Linux math coprocessor
1390 emulation can be found in <file:arch/x86/math-emu/README>.
1392 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1393 kernel, it won't hurt.
1397 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1399 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1400 the Memory Type Range Registers (MTRRs) may be used to control
1401 processor access to memory ranges. This is most useful if you have
1402 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1403 allows bus write transfers to be combined into a larger transfer
1404 before bursting over the PCI/AGP bus. This can increase performance
1405 of image write operations 2.5 times or more. Saying Y here creates a
1406 /proc/mtrr file which may be used to manipulate your processor's
1407 MTRRs. Typically the X server should use this.
1409 This code has a reasonably generic interface so that similar
1410 control registers on other processors can be easily supported
1413 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1414 Registers (ARRs) which provide a similar functionality to MTRRs. For
1415 these, the ARRs are used to emulate the MTRRs.
1416 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1417 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1418 write-combining. All of these processors are supported by this code
1419 and it makes sense to say Y here if you have one of them.
1421 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1422 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1423 can lead to all sorts of problems, so it's good to say Y here.
1425 You can safely say Y even if your machine doesn't have MTRRs, you'll
1426 just add about 9 KB to your kernel.
1428 See <file:Documentation/x86/mtrr.txt> for more information.
1430 config MTRR_SANITIZER
1432 prompt "MTRR cleanup support"
1435 Convert MTRR layout from continuous to discrete, so X drivers can
1436 add writeback entries.
1438 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1439 The largest mtrr entry size for a continuous block can be set with
1444 config MTRR_SANITIZER_ENABLE_DEFAULT
1445 int "MTRR cleanup enable value (0-1)"
1448 depends on MTRR_SANITIZER
1450 Enable mtrr cleanup default value
1452 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1453 int "MTRR cleanup spare reg num (0-7)"
1456 depends on MTRR_SANITIZER
1458 mtrr cleanup spare entries default, it can be changed via
1459 mtrr_spare_reg_nr=N on the kernel command line.
1463 prompt "x86 PAT support" if EXPERT
1466 Use PAT attributes to setup page level cache control.
1468 PATs are the modern equivalents of MTRRs and are much more
1469 flexible than MTRRs.
1471 Say N here if you see bootup problems (boot crash, boot hang,
1472 spontaneous reboots) or a non-working video driver.
1476 config ARCH_USES_PG_UNCACHED
1482 prompt "x86 architectural random number generator" if EXPERT
1484 Enable the x86 architectural RDRAND instruction
1485 (Intel Bull Mountain technology) to generate random numbers.
1486 If supported, this is a high bandwidth, cryptographically
1487 secure hardware random number generator.
1490 bool "EFI runtime service support"
1493 This enables the kernel to use EFI runtime services that are
1494 available (such as the EFI variable services).
1496 This option is only useful on systems that have EFI firmware.
1497 In addition, you should use the latest ELILO loader available
1498 at <http://elilo.sourceforge.net> in order to take advantage
1499 of EFI runtime services. However, even with this option, the
1500 resultant kernel should continue to boot on existing non-EFI
1504 bool "EFI stub support"
1507 This kernel feature allows a bzImage to be loaded directly
1508 by EFI firmware without the use of a bootloader.
1512 prompt "Enable seccomp to safely compute untrusted bytecode"
1514 This kernel feature is useful for number crunching applications
1515 that may need to compute untrusted bytecode during their
1516 execution. By using pipes or other transports made available to
1517 the process as file descriptors supporting the read/write
1518 syscalls, it's possible to isolate those applications in
1519 their own address space using seccomp. Once seccomp is
1520 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1521 and the task is only allowed to execute a few safe syscalls
1522 defined by each seccomp mode.
1524 If unsure, say Y. Only embedded should say N here.
1526 config CC_STACKPROTECTOR
1527 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1529 This option turns on the -fstack-protector GCC feature. This
1530 feature puts, at the beginning of functions, a canary value on
1531 the stack just before the return address, and validates
1532 the value just before actually returning. Stack based buffer
1533 overflows (that need to overwrite this return address) now also
1534 overwrite the canary, which gets detected and the attack is then
1535 neutralized via a kernel panic.
1537 This feature requires gcc version 4.2 or above, or a distribution
1538 gcc with the feature backported. Older versions are automatically
1539 detected and for those versions, this configuration option is
1540 ignored. (and a warning is printed during bootup)
1542 source kernel/Kconfig.hz
1545 bool "kexec system call"
1547 kexec is a system call that implements the ability to shutdown your
1548 current kernel, and to start another kernel. It is like a reboot
1549 but it is independent of the system firmware. And like a reboot
1550 you can start any kernel with it, not just Linux.
1552 The name comes from the similarity to the exec system call.
1554 It is an ongoing process to be certain the hardware in a machine
1555 is properly shutdown, so do not be surprised if this code does not
1556 initially work for you. It may help to enable device hotplugging
1557 support. As of this writing the exact hardware interface is
1558 strongly in flux, so no good recommendation can be made.
1561 bool "kernel crash dumps"
1562 depends on X86_64 || (X86_32 && HIGHMEM)
1564 Generate crash dump after being started by kexec.
1565 This should be normally only set in special crash dump kernels
1566 which are loaded in the main kernel with kexec-tools into
1567 a specially reserved region and then later executed after
1568 a crash by kdump/kexec. The crash dump kernel must be compiled
1569 to a memory address not used by the main kernel or BIOS using
1570 PHYSICAL_START, or it must be built as a relocatable image
1571 (CONFIG_RELOCATABLE=y).
1572 For more details see Documentation/kdump/kdump.txt
1575 bool "kexec jump (EXPERIMENTAL)"
1576 depends on EXPERIMENTAL
1577 depends on KEXEC && HIBERNATION
1579 Jump between original kernel and kexeced kernel and invoke
1580 code in physical address mode via KEXEC
1582 config PHYSICAL_START
1583 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1586 This gives the physical address where the kernel is loaded.
1588 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1589 bzImage will decompress itself to above physical address and
1590 run from there. Otherwise, bzImage will run from the address where
1591 it has been loaded by the boot loader and will ignore above physical
1594 In normal kdump cases one does not have to set/change this option
1595 as now bzImage can be compiled as a completely relocatable image
1596 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1597 address. This option is mainly useful for the folks who don't want
1598 to use a bzImage for capturing the crash dump and want to use a
1599 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1600 to be specifically compiled to run from a specific memory area
1601 (normally a reserved region) and this option comes handy.
1603 So if you are using bzImage for capturing the crash dump,
1604 leave the value here unchanged to 0x1000000 and set
1605 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1606 for capturing the crash dump change this value to start of
1607 the reserved region. In other words, it can be set based on
1608 the "X" value as specified in the "crashkernel=YM@XM"
1609 command line boot parameter passed to the panic-ed
1610 kernel. Please take a look at Documentation/kdump/kdump.txt
1611 for more details about crash dumps.
1613 Usage of bzImage for capturing the crash dump is recommended as
1614 one does not have to build two kernels. Same kernel can be used
1615 as production kernel and capture kernel. Above option should have
1616 gone away after relocatable bzImage support is introduced. But it
1617 is present because there are users out there who continue to use
1618 vmlinux for dump capture. This option should go away down the
1621 Don't change this unless you know what you are doing.
1624 bool "Build a relocatable kernel"
1627 This builds a kernel image that retains relocation information
1628 so it can be loaded someplace besides the default 1MB.
1629 The relocations tend to make the kernel binary about 10% larger,
1630 but are discarded at runtime.
1632 One use is for the kexec on panic case where the recovery kernel
1633 must live at a different physical address than the primary
1636 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1637 it has been loaded at and the compile time physical address
1638 (CONFIG_PHYSICAL_START) is ignored.
1640 # Relocation on x86-32 needs some additional build support
1641 config X86_NEED_RELOCS
1643 depends on X86_32 && RELOCATABLE
1645 config PHYSICAL_ALIGN
1646 hex "Alignment value to which kernel should be aligned" if X86_32
1648 range 0x2000 0x1000000
1650 This value puts the alignment restrictions on physical address
1651 where kernel is loaded and run from. Kernel is compiled for an
1652 address which meets above alignment restriction.
1654 If bootloader loads the kernel at a non-aligned address and
1655 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1656 address aligned to above value and run from there.
1658 If bootloader loads the kernel at a non-aligned address and
1659 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1660 load address and decompress itself to the address it has been
1661 compiled for and run from there. The address for which kernel is
1662 compiled already meets above alignment restrictions. Hence the
1663 end result is that kernel runs from a physical address meeting
1664 above alignment restrictions.
1666 Don't change this unless you know what you are doing.
1669 bool "Support for hot-pluggable CPUs"
1670 depends on SMP && HOTPLUG
1672 Say Y here to allow turning CPUs off and on. CPUs can be
1673 controlled through /sys/devices/system/cpu.
1674 ( Note: power management support will enable this option
1675 automatically on SMP systems. )
1676 Say N if you want to disable CPU hotplug.
1680 prompt "Compat VDSO support"
1681 depends on X86_32 || IA32_EMULATION
1683 Map the 32-bit VDSO to the predictable old-style address too.
1685 Say N here if you are running a sufficiently recent glibc
1686 version (2.3.3 or later), to remove the high-mapped
1687 VDSO mapping and to exclusively use the randomized VDSO.
1692 bool "Built-in kernel command line"
1694 Allow for specifying boot arguments to the kernel at
1695 build time. On some systems (e.g. embedded ones), it is
1696 necessary or convenient to provide some or all of the
1697 kernel boot arguments with the kernel itself (that is,
1698 to not rely on the boot loader to provide them.)
1700 To compile command line arguments into the kernel,
1701 set this option to 'Y', then fill in the
1702 the boot arguments in CONFIG_CMDLINE.
1704 Systems with fully functional boot loaders (i.e. non-embedded)
1705 should leave this option set to 'N'.
1708 string "Built-in kernel command string"
1709 depends on CMDLINE_BOOL
1712 Enter arguments here that should be compiled into the kernel
1713 image and used at boot time. If the boot loader provides a
1714 command line at boot time, it is appended to this string to
1715 form the full kernel command line, when the system boots.
1717 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1718 change this behavior.
1720 In most cases, the command line (whether built-in or provided
1721 by the boot loader) should specify the device for the root
1724 config CMDLINE_OVERRIDE
1725 bool "Built-in command line overrides boot loader arguments"
1726 depends on CMDLINE_BOOL
1728 Set this option to 'Y' to have the kernel ignore the boot loader
1729 command line, and use ONLY the built-in command line.
1731 This is used to work around broken boot loaders. This should
1732 be set to 'N' under normal conditions.
1736 config ARCH_ENABLE_MEMORY_HOTPLUG
1738 depends on X86_64 || (X86_32 && HIGHMEM)
1740 config ARCH_ENABLE_MEMORY_HOTREMOVE
1742 depends on MEMORY_HOTPLUG
1744 config USE_PERCPU_NUMA_NODE_ID
1748 menu "Power management and ACPI options"
1750 config ARCH_HIBERNATION_HEADER
1752 depends on X86_64 && HIBERNATION
1754 source "kernel/power/Kconfig"
1756 source "drivers/acpi/Kconfig"
1758 source "drivers/sfi/Kconfig"
1765 tristate "APM (Advanced Power Management) BIOS support"
1766 depends on X86_32 && PM_SLEEP
1768 APM is a BIOS specification for saving power using several different
1769 techniques. This is mostly useful for battery powered laptops with
1770 APM compliant BIOSes. If you say Y here, the system time will be
1771 reset after a RESUME operation, the /proc/apm device will provide
1772 battery status information, and user-space programs will receive
1773 notification of APM "events" (e.g. battery status change).
1775 If you select "Y" here, you can disable actual use of the APM
1776 BIOS by passing the "apm=off" option to the kernel at boot time.
1778 Note that the APM support is almost completely disabled for
1779 machines with more than one CPU.
1781 In order to use APM, you will need supporting software. For location
1782 and more information, read <file:Documentation/power/apm-acpi.txt>
1783 and the Battery Powered Linux mini-HOWTO, available from
1784 <http://www.tldp.org/docs.html#howto>.
1786 This driver does not spin down disk drives (see the hdparm(8)
1787 manpage ("man 8 hdparm") for that), and it doesn't turn off
1788 VESA-compliant "green" monitors.
1790 This driver does not support the TI 4000M TravelMate and the ACER
1791 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1792 desktop machines also don't have compliant BIOSes, and this driver
1793 may cause those machines to panic during the boot phase.
1795 Generally, if you don't have a battery in your machine, there isn't
1796 much point in using this driver and you should say N. If you get
1797 random kernel OOPSes or reboots that don't seem to be related to
1798 anything, try disabling/enabling this option (or disabling/enabling
1801 Some other things you should try when experiencing seemingly random,
1804 1) make sure that you have enough swap space and that it is
1806 2) pass the "no-hlt" option to the kernel
1807 3) switch on floating point emulation in the kernel and pass
1808 the "no387" option to the kernel
1809 4) pass the "floppy=nodma" option to the kernel
1810 5) pass the "mem=4M" option to the kernel (thereby disabling
1811 all but the first 4 MB of RAM)
1812 6) make sure that the CPU is not over clocked.
1813 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1814 8) disable the cache from your BIOS settings
1815 9) install a fan for the video card or exchange video RAM
1816 10) install a better fan for the CPU
1817 11) exchange RAM chips
1818 12) exchange the motherboard.
1820 To compile this driver as a module, choose M here: the
1821 module will be called apm.
1825 config APM_IGNORE_USER_SUSPEND
1826 bool "Ignore USER SUSPEND"
1828 This option will ignore USER SUSPEND requests. On machines with a
1829 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1830 series notebooks, it is necessary to say Y because of a BIOS bug.
1832 config APM_DO_ENABLE
1833 bool "Enable PM at boot time"
1835 Enable APM features at boot time. From page 36 of the APM BIOS
1836 specification: "When disabled, the APM BIOS does not automatically
1837 power manage devices, enter the Standby State, enter the Suspend
1838 State, or take power saving steps in response to CPU Idle calls."
1839 This driver will make CPU Idle calls when Linux is idle (unless this
1840 feature is turned off -- see "Do CPU IDLE calls", below). This
1841 should always save battery power, but more complicated APM features
1842 will be dependent on your BIOS implementation. You may need to turn
1843 this option off if your computer hangs at boot time when using APM
1844 support, or if it beeps continuously instead of suspending. Turn
1845 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1846 T400CDT. This is off by default since most machines do fine without
1850 bool "Make CPU Idle calls when idle"
1852 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1853 On some machines, this can activate improved power savings, such as
1854 a slowed CPU clock rate, when the machine is idle. These idle calls
1855 are made after the idle loop has run for some length of time (e.g.,
1856 333 mS). On some machines, this will cause a hang at boot time or
1857 whenever the CPU becomes idle. (On machines with more than one CPU,
1858 this option does nothing.)
1860 config APM_DISPLAY_BLANK
1861 bool "Enable console blanking using APM"
1863 Enable console blanking using the APM. Some laptops can use this to
1864 turn off the LCD backlight when the screen blanker of the Linux
1865 virtual console blanks the screen. Note that this is only used by
1866 the virtual console screen blanker, and won't turn off the backlight
1867 when using the X Window system. This also doesn't have anything to
1868 do with your VESA-compliant power-saving monitor. Further, this
1869 option doesn't work for all laptops -- it might not turn off your
1870 backlight at all, or it might print a lot of errors to the console,
1871 especially if you are using gpm.
1873 config APM_ALLOW_INTS
1874 bool "Allow interrupts during APM BIOS calls"
1876 Normally we disable external interrupts while we are making calls to
1877 the APM BIOS as a measure to lessen the effects of a badly behaving
1878 BIOS implementation. The BIOS should reenable interrupts if it
1879 needs to. Unfortunately, some BIOSes do not -- especially those in
1880 many of the newer IBM Thinkpads. If you experience hangs when you
1881 suspend, try setting this to Y. Otherwise, say N.
1885 source "drivers/cpufreq/Kconfig"
1887 source "drivers/cpuidle/Kconfig"
1889 source "drivers/idle/Kconfig"
1894 menu "Bus options (PCI etc.)"
1899 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1901 Find out whether you have a PCI motherboard. PCI is the name of a
1902 bus system, i.e. the way the CPU talks to the other stuff inside
1903 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1904 VESA. If you have PCI, say Y, otherwise N.
1907 prompt "PCI access mode"
1908 depends on X86_32 && PCI
1911 On PCI systems, the BIOS can be used to detect the PCI devices and
1912 determine their configuration. However, some old PCI motherboards
1913 have BIOS bugs and may crash if this is done. Also, some embedded
1914 PCI-based systems don't have any BIOS at all. Linux can also try to
1915 detect the PCI hardware directly without using the BIOS.
1917 With this option, you can specify how Linux should detect the
1918 PCI devices. If you choose "BIOS", the BIOS will be used,
1919 if you choose "Direct", the BIOS won't be used, and if you
1920 choose "MMConfig", then PCI Express MMCONFIG will be used.
1921 If you choose "Any", the kernel will try MMCONFIG, then the
1922 direct access method and falls back to the BIOS if that doesn't
1923 work. If unsure, go with the default, which is "Any".
1928 config PCI_GOMMCONFIG
1945 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1947 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1950 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1954 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1958 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1962 depends on PCI && XEN
1970 bool "Support mmconfig PCI config space access"
1971 depends on X86_64 && PCI && ACPI
1973 config PCI_CNB20LE_QUIRK
1974 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1976 depends on PCI && EXPERIMENTAL
1978 Read the PCI windows out of the CNB20LE host bridge. This allows
1979 PCI hotplug to work on systems with the CNB20LE chipset which do
1982 There's no public spec for this chipset, and this functionality
1983 is known to be incomplete.
1985 You should say N unless you know you need this.
1987 source "drivers/pci/pcie/Kconfig"
1989 source "drivers/pci/Kconfig"
1991 # x86_64 have no ISA slots, but can have ISA-style DMA.
1993 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1996 Enables ISA-style DMA support for devices requiring such controllers.
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"
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"
2067 Add support for detecting the unique features of the OLPC
2071 bool "OLPC XO-1 Power Management"
2072 depends on OLPC && MFD_CS5535 && PM_SLEEP
2075 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2078 bool "OLPC XO-1 Real Time Clock"
2079 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2081 Add support for the XO-1 real time clock, which can be used as a
2082 programmable wakeup source.
2085 bool "OLPC XO-1 SCI extras"
2086 depends on OLPC && OLPC_XO1_PM
2091 Add support for SCI-based features of the OLPC XO-1 laptop:
2092 - EC-driven system wakeups
2096 - AC adapter status updates
2097 - Battery status updates
2099 config OLPC_XO15_SCI
2100 bool "OLPC XO-1.5 SCI extras"
2101 depends on OLPC && ACPI
2104 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2105 - EC-driven system wakeups
2106 - AC adapter status updates
2107 - Battery status updates
2110 bool "PCEngines ALIX System Support (LED setup)"
2113 This option enables system support for the PCEngines ALIX.
2114 At present this just sets up LEDs for GPIO control on
2115 ALIX2/3/6 boards. However, other system specific setup should
2118 Note: You must still enable the drivers for GPIO and LED support
2119 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2121 Note: You have to set alix.force=1 for boards with Award BIOS.
2124 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2127 This option enables system support for the Soekris Engineering net5501.
2130 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2134 This option enables system support for the Traverse Technologies GEOS.
2140 depends on CPU_SUP_AMD && PCI
2142 source "drivers/pcmcia/Kconfig"
2144 source "drivers/pci/hotplug/Kconfig"
2147 bool "RapidIO support"
2151 If you say Y here, the kernel will include drivers and
2152 infrastructure code to support RapidIO interconnect devices.
2154 source "drivers/rapidio/Kconfig"
2159 menu "Executable file formats / Emulations"
2161 source "fs/Kconfig.binfmt"
2163 config IA32_EMULATION
2164 bool "IA32 Emulation"
2166 select COMPAT_BINFMT_ELF
2168 Include code to run legacy 32-bit programs under a
2169 64-bit kernel. You should likely turn this on, unless you're
2170 100% sure that you don't have any 32-bit programs left.
2173 tristate "IA32 a.out support"
2174 depends on IA32_EMULATION
2176 Support old a.out binaries in the 32bit emulation.
2179 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2180 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2182 Include code to run binaries for the x32 native 32-bit ABI
2183 for 64-bit processors. An x32 process gets access to the
2184 full 64-bit register file and wide data path while leaving
2185 pointers at 32 bits for smaller memory footprint.
2187 You will need a recent binutils (2.22 or later) with
2188 elf32_x86_64 support enabled to compile a kernel with this
2193 depends on IA32_EMULATION || X86_X32
2194 select ARCH_WANT_OLD_COMPAT_IPC
2196 config COMPAT_FOR_U64_ALIGNMENT
2200 config SYSVIPC_COMPAT
2202 depends on COMPAT && SYSVIPC
2206 depends on COMPAT && KEYS
2212 config HAVE_ATOMIC_IOMAP
2216 config HAVE_TEXT_POKE_SMP
2218 select STOP_MACHINE if SMP
2220 source "net/Kconfig"
2222 source "drivers/Kconfig"
2224 source "drivers/firmware/Kconfig"
2228 source "arch/x86/Kconfig.debug"
2230 source "security/Kconfig"
2232 source "crypto/Kconfig"
2234 source "arch/x86/kvm/Kconfig"
2236 source "lib/Kconfig"