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)
77 select ARCH_HAVE_NMI_SAFE_CMPXCHG
78 select ARCH_SUPPORTS_ATOMIC_RMW
80 config INSTRUCTION_DECODER
81 def_bool (KPROBES || PERF_EVENTS)
85 default "elf32-i386" if X86_32
86 default "elf64-x86-64" if X86_64
90 default "arch/x86/configs/i386_defconfig" if X86_32
91 default "arch/x86/configs/x86_64_defconfig" if X86_64
93 config GENERIC_CMOS_UPDATE
96 config CLOCKSOURCE_WATCHDOG
99 config GENERIC_CLOCKEVENTS
102 config ARCH_CLOCKSOURCE_DATA
106 config GENERIC_CLOCKEVENTS_BROADCAST
108 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
110 config LOCKDEP_SUPPORT
113 config STACKTRACE_SUPPORT
116 config HAVE_LATENCYTOP_SUPPORT
123 bool "DMA memory allocation support" if EXPERT
126 DMA memory allocation support allows devices with less than 32-bit
127 addressing to allocate within the first 16MB of address space.
128 Disable if no such devices will be used.
135 config NEED_DMA_MAP_STATE
136 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
138 config NEED_SG_DMA_LENGTH
141 config GENERIC_ISA_DMA
150 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
152 config GENERIC_BUG_RELATIVE_POINTERS
155 config GENERIC_HWEIGHT
161 config ARCH_MAY_HAVE_PC_FDC
164 config RWSEM_GENERIC_SPINLOCK
167 config RWSEM_XCHGADD_ALGORITHM
170 config ARCH_HAS_CPU_IDLE_WAIT
173 config GENERIC_CALIBRATE_DELAY
176 config GENERIC_TIME_VSYSCALL
180 config ARCH_HAS_CPU_RELAX
183 config ARCH_HAS_DEFAULT_IDLE
186 config ARCH_HAS_CACHE_LINE_SIZE
189 config HAVE_SETUP_PER_CPU_AREA
192 config NEED_PER_CPU_EMBED_FIRST_CHUNK
195 config NEED_PER_CPU_PAGE_FIRST_CHUNK
198 config ARCH_HIBERNATION_POSSIBLE
201 config ARCH_SUSPEND_POSSIBLE
208 config ARCH_POPULATES_NODE_MAP
215 config ARCH_SUPPORTS_OPTIMIZED_INLINING
218 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
221 config HAVE_INTEL_TXT
223 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
227 depends on X86_32 && SMP
231 depends on X86_64 && SMP
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
241 config ARCH_HWEIGHT_CFLAGS
243 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
244 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
249 config ARCH_CPU_PROBE_RELEASE
251 depends on HOTPLUG_CPU
253 source "init/Kconfig"
254 source "kernel/Kconfig.freezer"
256 menu "Processor type and features"
258 source "kernel/time/Kconfig"
261 bool "Symmetric multi-processing support"
263 This enables support for systems with more than one CPU. If you have
264 a system with only one CPU, like most personal computers, say N. If
265 you have a system with more than one CPU, say Y.
267 If you say N here, the kernel will run on single and multiprocessor
268 machines, but will use only one CPU of a multiprocessor machine. If
269 you say Y here, the kernel will run on many, but not all,
270 singleprocessor machines. On a singleprocessor machine, the kernel
271 will run faster if you say N here.
273 Note that if you say Y here and choose architecture "586" or
274 "Pentium" under "Processor family", the kernel will not work on 486
275 architectures. Similarly, multiprocessor kernels for the "PPro"
276 architecture may not work on all Pentium based boards.
278 People using multiprocessor machines who say Y here should also say
279 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
280 Management" code will be disabled if you say Y here.
282 See also <file:Documentation/x86/i386/IO-APIC.txt>,
283 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
284 <http://www.tldp.org/docs.html#howto>.
286 If you don't know what to do here, say N.
289 bool "Support x2apic"
290 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
292 This enables x2apic support on CPUs that have this feature.
294 This allows 32-bit apic IDs (so it can support very large systems),
295 and accesses the local apic via MSRs not via mmio.
297 If you don't know what to do here, say N.
300 bool "Enable MPS table" if ACPI
302 depends on X86_LOCAL_APIC
304 For old smp systems that do not have proper acpi support. Newer systems
305 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
308 bool "Support for big SMP systems with more than 8 CPUs"
309 depends on X86_32 && SMP
311 This option is needed for the systems that have more than 8 CPUs
314 config X86_EXTENDED_PLATFORM
315 bool "Support for extended (non-PC) x86 platforms"
318 If you disable this option then the kernel will only support
319 standard PC platforms. (which covers the vast majority of
322 If you enable this option then you'll be able to select support
323 for the following (non-PC) 32 bit x86 platforms:
327 SGI 320/540 (Visual Workstation)
328 Summit/EXA (IBM x440)
329 Unisys ES7000 IA32 series
330 Moorestown MID devices
332 If you have one of these systems, or if you want to build a
333 generic distribution kernel, say Y here - otherwise say N.
337 config X86_EXTENDED_PLATFORM
338 bool "Support for extended (non-PC) x86 platforms"
341 If you disable this option then the kernel will only support
342 standard PC platforms. (which covers the vast majority of
345 If you enable this option then you'll be able to select support
346 for the following (non-PC) 64 bit x86 platforms:
350 If you have one of these systems, or if you want to build a
351 generic distribution kernel, say Y here - otherwise say N.
353 # This is an alphabetically sorted list of 64 bit extended platforms
354 # Please maintain the alphabetic order if and when there are additions
358 select PARAVIRT_GUEST
360 depends on X86_64 && PCI
361 depends on X86_EXTENDED_PLATFORM
363 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
364 supposed to run on these EM64T-based machines. Only choose this option
365 if you have one of these machines.
368 bool "SGI Ultraviolet"
370 depends on X86_EXTENDED_PLATFORM
372 depends on X86_X2APIC
374 This option is needed in order to support SGI Ultraviolet systems.
375 If you don't have one of these, you should say N here.
377 # Following is an alphabetically sorted list of 32 bit extended platforms
378 # Please maintain the alphabetic order if and when there are additions
381 bool "CE4100 TV platform"
383 depends on PCI_GODIRECT
385 depends on X86_EXTENDED_PLATFORM
386 select X86_REBOOTFIXUPS
388 select OF_EARLY_FLATTREE
390 Select for the Intel CE media processor (CE4100) SOC.
391 This option compiles in support for the CE4100 SOC for settop
392 boxes and media devices.
394 config X86_WANT_INTEL_MID
395 bool "Intel MID platform support"
397 depends on X86_EXTENDED_PLATFORM
399 Select to build a kernel capable of supporting Intel MID platform
400 systems which do not have the PCI legacy interfaces (Moorestown,
401 Medfield). If you are building for a PC class system say N here.
403 if X86_WANT_INTEL_MID
409 bool "Moorestown MID platform"
412 depends on X86_IO_APIC
417 select X86_PLATFORM_DEVICES
420 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
421 Internet Device(MID) platform. Moorestown consists of two chips:
422 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
423 Unlike standard x86 PCs, Moorestown does not have many legacy devices
424 nor standard legacy replacement devices/features. e.g. Moorestown does
425 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
430 bool "RDC R-321x SoC"
432 depends on X86_EXTENDED_PLATFORM
434 select X86_REBOOTFIXUPS
436 This option is needed for RDC R-321x system-on-chip, also known
438 If you don't have one of these chips, you should say N here.
440 config X86_32_NON_STANDARD
441 bool "Support non-standard 32-bit SMP architectures"
442 depends on X86_32 && SMP
443 depends on X86_EXTENDED_PLATFORM
445 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
446 subarchitectures. It is intended for a generic binary kernel.
447 if you select them all, kernel will probe it one by one. and will
450 # Alphabetically sorted list of Non standard 32 bit platforms
453 bool "NUMAQ (IBM/Sequent)"
454 depends on X86_32_NON_STANDARD
459 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
460 NUMA multiquad box. This changes the way that processors are
461 bootstrapped, and uses Clustered Logical APIC addressing mode instead
462 of Flat Logical. You will need a new lynxer.elf file to flash your
463 firmware with - send email to <Martin.Bligh@us.ibm.com>.
465 config X86_SUPPORTS_MEMORY_FAILURE
467 # MCE code calls memory_failure():
469 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
470 depends on !X86_NUMAQ
471 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
472 depends on X86_64 || !SPARSEMEM
473 select ARCH_SUPPORTS_MEMORY_FAILURE
476 bool "SGI 320/540 (Visual Workstation)"
477 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
478 depends on X86_32_NON_STANDARD
480 The SGI Visual Workstation series is an IA32-based workstation
481 based on SGI systems chips with some legacy PC hardware attached.
483 Say Y here to create a kernel to run on the SGI 320 or 540.
485 A kernel compiled for the Visual Workstation will run on general
486 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
489 bool "Summit/EXA (IBM x440)"
490 depends on X86_32_NON_STANDARD
492 This option is needed for IBM systems that use the Summit/EXA chipset.
493 In particular, it is needed for the x440.
496 bool "Unisys ES7000 IA32 series"
497 depends on X86_32_NON_STANDARD && X86_BIGSMP
499 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
500 supposed to run on an IA32-based Unisys ES7000 system.
503 tristate "Eurobraille/Iris poweroff module"
506 The Iris machines from EuroBraille do not have APM or ACPI support
507 to shut themselves down properly. A special I/O sequence is
508 needed to do so, which is what this module does at
511 This is only for Iris machines from EuroBraille.
515 config SCHED_OMIT_FRAME_POINTER
517 prompt "Single-depth WCHAN output"
520 Calculate simpler /proc/<PID>/wchan values. If this option
521 is disabled then wchan values will recurse back to the
522 caller function. This provides more accurate wchan values,
523 at the expense of slightly more scheduling overhead.
525 If in doubt, say "Y".
527 menuconfig PARAVIRT_GUEST
528 bool "Paravirtualized guest support"
530 Say Y here to get to see options related to running Linux under
531 various hypervisors. This option alone does not add any kernel code.
533 If you say N, all options in this submenu will be skipped and disabled.
537 config PARAVIRT_TIME_ACCOUNTING
538 bool "Paravirtual steal time accounting"
542 Select this option to enable fine granularity task steal time
543 accounting. Time spent executing other tasks in parallel with
544 the current vCPU is discounted from the vCPU power. To account for
545 that, there can be a small performance impact.
547 If in doubt, say N here.
549 source "arch/x86/xen/Kconfig"
552 bool "KVM paravirtualized clock"
554 select PARAVIRT_CLOCK
556 Turning on this option will allow you to run a paravirtualized clock
557 when running over the KVM hypervisor. Instead of relying on a PIT
558 (or probably other) emulation by the underlying device model, the host
559 provides the guest with timing infrastructure such as time of day, and
563 bool "KVM Guest support"
566 This option enables various optimizations for running under the KVM
569 source "arch/x86/lguest/Kconfig"
572 bool "Enable paravirtualization code"
574 This changes the kernel so it can modify itself when it is run
575 under a hypervisor, potentially improving performance significantly
576 over full virtualization. However, when run without a hypervisor
577 the kernel is theoretically slower and slightly larger.
579 config PARAVIRT_SPINLOCKS
580 bool "Paravirtualization layer for spinlocks"
581 depends on PARAVIRT && SMP && EXPERIMENTAL
583 Paravirtualized spinlocks allow a pvops backend to replace the
584 spinlock implementation with something virtualization-friendly
585 (for example, block the virtual CPU rather than spinning).
587 Unfortunately the downside is an up to 5% performance hit on
588 native kernels, with various workloads.
590 If you are unsure how to answer this question, answer N.
592 config PARAVIRT_CLOCK
597 config PARAVIRT_DEBUG
598 bool "paravirt-ops debugging"
599 depends on PARAVIRT && DEBUG_KERNEL
601 Enable to debug paravirt_ops internals. Specifically, BUG if
602 a paravirt_op is missing when it is called.
610 This option adds a kernel parameter 'memtest', which allows memtest
612 memtest=0, mean disabled; -- default
613 memtest=1, mean do 1 test pattern;
615 memtest=4, mean do 4 test patterns.
616 If you are unsure how to answer this question, answer N.
618 config X86_SUMMIT_NUMA
620 depends on X86_32 && NUMA && X86_32_NON_STANDARD
622 config X86_CYCLONE_TIMER
624 depends on X86_32_NON_STANDARD
626 source "arch/x86/Kconfig.cpu"
630 prompt "HPET Timer Support" if X86_32
632 Use the IA-PC HPET (High Precision Event Timer) to manage
633 time in preference to the PIT and RTC, if a HPET is
635 HPET is the next generation timer replacing legacy 8254s.
636 The HPET provides a stable time base on SMP
637 systems, unlike the TSC, but it is more expensive to access,
638 as it is off-chip. You can find the HPET spec at
639 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
641 You can safely choose Y here. However, HPET will only be
642 activated if the platform and the BIOS support this feature.
643 Otherwise the 8254 will be used for timing services.
645 Choose N to continue using the legacy 8254 timer.
647 config HPET_EMULATE_RTC
649 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
653 prompt "Langwell APB Timer Support" if X86_MRST
656 APB timer is the replacement for 8254, HPET on X86 MID platforms.
657 The APBT provides a stable time base on SMP
658 systems, unlike the TSC, but it is more expensive to access,
659 as it is off-chip. APB timers are always running regardless of CPU
660 C states, they are used as per CPU clockevent device when possible.
662 # Mark as expert because too many people got it wrong.
663 # The code disables itself when not needed.
666 bool "Enable DMI scanning" if EXPERT
668 Enabled scanning of DMI to identify machine quirks. Say Y
669 here unless you have verified that your setup is not
670 affected by entries in the DMI blacklist. Required by PNP
674 bool "GART IOMMU support" if EXPERT
677 depends on X86_64 && PCI && AMD_NB
679 Support for full DMA access of devices with 32bit memory access only
680 on systems with more than 3GB. This is usually needed for USB,
681 sound, many IDE/SATA chipsets and some other devices.
682 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
683 based hardware IOMMU and a software bounce buffer based IOMMU used
684 on Intel systems and as fallback.
685 The code is only active when needed (enough memory and limited
686 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
690 bool "IBM Calgary IOMMU support"
692 depends on X86_64 && PCI && EXPERIMENTAL
694 Support for hardware IOMMUs in IBM's xSeries x366 and x460
695 systems. Needed to run systems with more than 3GB of memory
696 properly with 32-bit PCI devices that do not support DAC
697 (Double Address Cycle). Calgary also supports bus level
698 isolation, where all DMAs pass through the IOMMU. This
699 prevents them from going anywhere except their intended
700 destination. This catches hard-to-find kernel bugs and
701 mis-behaving drivers and devices that do not use the DMA-API
702 properly to set up their DMA buffers. The IOMMU can be
703 turned off at boot time with the iommu=off parameter.
704 Normally the kernel will make the right choice by itself.
707 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
709 prompt "Should Calgary be enabled by default?"
710 depends on CALGARY_IOMMU
712 Should Calgary be enabled by default? if you choose 'y', Calgary
713 will be used (if it exists). If you choose 'n', Calgary will not be
714 used even if it exists. If you choose 'n' and would like to use
715 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
718 # need this always selected by IOMMU for the VIA workaround
722 Support for software bounce buffers used on x86-64 systems
723 which don't have a hardware IOMMU (e.g. the current generation
724 of Intel's x86-64 CPUs). Using this PCI devices which can only
725 access 32-bits of memory can be used on systems with more than
726 3 GB of memory. If unsure, say Y.
729 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
732 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
733 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
734 select CPUMASK_OFFSTACK
736 Enable maximum number of CPUS and NUMA Nodes for this architecture.
740 int "Maximum number of CPUs" if SMP && !MAXSMP
741 range 2 8 if SMP && X86_32 && !X86_BIGSMP
742 range 2 512 if SMP && !MAXSMP
744 default "4096" if MAXSMP
745 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
748 This allows you to specify the maximum number of CPUs which this
749 kernel will support. The maximum supported value is 512 and the
750 minimum value which makes sense is 2.
752 This is purely to save memory - each supported CPU adds
753 approximately eight kilobytes to the kernel image.
756 bool "SMT (Hyperthreading) scheduler support"
759 SMT scheduler support improves the CPU scheduler's decision making
760 when dealing with Intel Pentium 4 chips with HyperThreading at a
761 cost of slightly increased overhead in some places. If unsure say
766 prompt "Multi-core scheduler support"
769 Multi-core scheduler support improves the CPU scheduler's decision
770 making when dealing with multi-core CPU chips at a cost of slightly
771 increased overhead in some places. If unsure say N here.
773 config IRQ_TIME_ACCOUNTING
774 bool "Fine granularity task level IRQ time accounting"
777 Select this option to enable fine granularity task irq time
778 accounting. This is done by reading a timestamp on each
779 transitions between softirq and hardirq state, so there can be a
780 small performance impact.
782 If in doubt, say N here.
784 source "kernel/Kconfig.preempt"
787 bool "Local APIC support on uniprocessors"
788 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
790 A local APIC (Advanced Programmable Interrupt Controller) is an
791 integrated interrupt controller in the CPU. If you have a single-CPU
792 system which has a processor with a local APIC, you can say Y here to
793 enable and use it. If you say Y here even though your machine doesn't
794 have a local APIC, then the kernel will still run with no slowdown at
795 all. The local APIC supports CPU-generated self-interrupts (timer,
796 performance counters), and the NMI watchdog which detects hard
800 bool "IO-APIC support on uniprocessors"
801 depends on X86_UP_APIC
803 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
804 SMP-capable replacement for PC-style interrupt controllers. Most
805 SMP systems and many recent uniprocessor systems have one.
807 If you have a single-CPU system with an IO-APIC, you can say Y here
808 to use it. If you say Y here even though your machine doesn't have
809 an IO-APIC, then the kernel will still run with no slowdown at all.
811 config X86_LOCAL_APIC
813 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
817 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
819 config X86_VISWS_APIC
821 depends on X86_32 && X86_VISWS
823 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
824 bool "Reroute for broken boot IRQs"
825 depends on X86_IO_APIC
827 This option enables a workaround that fixes a source of
828 spurious interrupts. This is recommended when threaded
829 interrupt handling is used on systems where the generation of
830 superfluous "boot interrupts" cannot be disabled.
832 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
833 entry in the chipset's IO-APIC is masked (as, e.g. the RT
834 kernel does during interrupt handling). On chipsets where this
835 boot IRQ generation cannot be disabled, this workaround keeps
836 the original IRQ line masked so that only the equivalent "boot
837 IRQ" is delivered to the CPUs. The workaround also tells the
838 kernel to set up the IRQ handler on the boot IRQ line. In this
839 way only one interrupt is delivered to the kernel. Otherwise
840 the spurious second interrupt may cause the kernel to bring
841 down (vital) interrupt lines.
843 Only affects "broken" chipsets. Interrupt sharing may be
844 increased on these systems.
847 bool "Machine Check / overheating reporting"
849 Machine Check support allows the processor to notify the
850 kernel if it detects a problem (e.g. overheating, data corruption).
851 The action the kernel takes depends on the severity of the problem,
852 ranging from warning messages to halting the machine.
856 prompt "Intel MCE features"
857 depends on X86_MCE && X86_LOCAL_APIC
859 Additional support for intel specific MCE features such as
864 prompt "AMD MCE features"
865 depends on X86_MCE && X86_LOCAL_APIC
867 Additional support for AMD specific MCE features such as
868 the DRAM Error Threshold.
870 config X86_ANCIENT_MCE
871 bool "Support for old Pentium 5 / WinChip machine checks"
872 depends on X86_32 && X86_MCE
874 Include support for machine check handling on old Pentium 5 or WinChip
875 systems. These typically need to be enabled explicitely on the command
878 config X86_MCE_THRESHOLD
879 depends on X86_MCE_AMD || X86_MCE_INTEL
882 config X86_MCE_INJECT
884 tristate "Machine check injector support"
886 Provide support for injecting machine checks for testing purposes.
887 If you don't know what a machine check is and you don't do kernel
888 QA it is safe to say n.
890 config X86_THERMAL_VECTOR
892 depends on X86_MCE_INTEL
895 bool "Enable VM86 support" if EXPERT
899 This option is required by programs like DOSEMU to run 16-bit legacy
900 code on X86 processors. It also may be needed by software like
901 XFree86 to initialize some video cards via BIOS. Disabling this
902 option saves about 6k.
909 tristate "Toshiba Laptop support"
912 This adds a driver to safely access the System Management Mode of
913 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
914 not work on models with a Phoenix BIOS. The System Management Mode
915 is used to set the BIOS and power saving options on Toshiba portables.
917 For information on utilities to make use of this driver see the
918 Toshiba Linux utilities web site at:
919 <http://www.buzzard.org.uk/toshiba/>.
921 Say Y if you intend to run this kernel on a Toshiba portable.
925 tristate "Dell laptop support"
928 This adds a driver to safely access the System Management Mode
929 of the CPU on the Dell Inspiron 8000. The System Management Mode
930 is used to read cpu temperature and cooling fan status and to
931 control the fans on the I8K portables.
933 This driver has been tested only on the Inspiron 8000 but it may
934 also work with other Dell laptops. You can force loading on other
935 models by passing the parameter `force=1' to the module. Use at
938 For information on utilities to make use of this driver see the
939 I8K Linux utilities web site at:
940 <http://people.debian.org/~dz/i8k/>
942 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
945 config X86_REBOOTFIXUPS
946 bool "Enable X86 board specific fixups for reboot"
949 This enables chipset and/or board specific fixups to be done
950 in order to get reboot to work correctly. This is only needed on
951 some combinations of hardware and BIOS. The symptom, for which
952 this config is intended, is when reboot ends with a stalled/hung
955 Currently, the only fixup is for the Geode machines using
956 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
958 Say Y if you want to enable the fixup. Currently, it's safe to
959 enable this option even if you don't need it.
963 tristate "/dev/cpu/microcode - microcode support"
966 If you say Y here, you will be able to update the microcode on
967 certain Intel and AMD processors. The Intel support is for the
968 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
969 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
970 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
971 You will obviously need the actual microcode binary data itself
972 which is not shipped with the Linux kernel.
974 This option selects the general module only, you need to select
975 at least one vendor specific module as well.
977 To compile this driver as a module, choose M here: the
978 module will be called microcode.
980 config MICROCODE_INTEL
981 bool "Intel microcode patch loading support"
986 This options enables microcode patch loading support for Intel
989 For latest news and information on obtaining all the required
990 Intel ingredients for this driver, check:
991 <http://www.urbanmyth.org/microcode/>.
994 bool "AMD microcode patch loading support"
998 If you select this option, microcode patch loading support for AMD
999 processors will be enabled.
1001 config MICROCODE_OLD_INTERFACE
1003 depends on MICROCODE
1006 tristate "/dev/cpu/*/msr - Model-specific register support"
1008 This device gives privileged processes access to the x86
1009 Model-Specific Registers (MSRs). It is a character device with
1010 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1011 MSR accesses are directed to a specific CPU on multi-processor
1015 tristate "/dev/cpu/*/cpuid - CPU information support"
1017 This device gives processes access to the x86 CPUID instruction to
1018 be executed on a specific processor. It is a character device
1019 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1023 prompt "High Memory Support"
1024 default HIGHMEM64G if X86_NUMAQ
1030 depends on !X86_NUMAQ
1032 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1033 However, the address space of 32-bit x86 processors is only 4
1034 Gigabytes large. That means that, if you have a large amount of
1035 physical memory, not all of it can be "permanently mapped" by the
1036 kernel. The physical memory that's not permanently mapped is called
1039 If you are compiling a kernel which will never run on a machine with
1040 more than 1 Gigabyte total physical RAM, answer "off" here (default
1041 choice and suitable for most users). This will result in a "3GB/1GB"
1042 split: 3GB are mapped so that each process sees a 3GB virtual memory
1043 space and the remaining part of the 4GB virtual memory space is used
1044 by the kernel to permanently map as much physical memory as
1047 If the machine has between 1 and 4 Gigabytes physical RAM, then
1050 If more than 4 Gigabytes is used then answer "64GB" here. This
1051 selection turns Intel PAE (Physical Address Extension) mode on.
1052 PAE implements 3-level paging on IA32 processors. PAE is fully
1053 supported by Linux, PAE mode is implemented on all recent Intel
1054 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1055 then the kernel will not boot on CPUs that don't support PAE!
1057 The actual amount of total physical memory will either be
1058 auto detected or can be forced by using a kernel command line option
1059 such as "mem=256M". (Try "man bootparam" or see the documentation of
1060 your boot loader (lilo or loadlin) about how to pass options to the
1061 kernel at boot time.)
1063 If unsure, say "off".
1067 depends on !X86_NUMAQ
1069 Select this if you have a 32-bit processor and between 1 and 4
1070 gigabytes of physical RAM.
1074 depends on !M386 && !M486
1077 Select this if you have a 32-bit processor and more than 4
1078 gigabytes of physical RAM.
1083 depends on EXPERIMENTAL
1084 prompt "Memory split" if EXPERT
1088 Select the desired split between kernel and user memory.
1090 If the address range available to the kernel is less than the
1091 physical memory installed, the remaining memory will be available
1092 as "high memory". Accessing high memory is a little more costly
1093 than low memory, as it needs to be mapped into the kernel first.
1094 Note that increasing the kernel address space limits the range
1095 available to user programs, making the address space there
1096 tighter. Selecting anything other than the default 3G/1G split
1097 will also likely make your kernel incompatible with binary-only
1100 If you are not absolutely sure what you are doing, leave this
1104 bool "3G/1G user/kernel split"
1105 config VMSPLIT_3G_OPT
1107 bool "3G/1G user/kernel split (for full 1G low memory)"
1109 bool "2G/2G user/kernel split"
1110 config VMSPLIT_2G_OPT
1112 bool "2G/2G user/kernel split (for full 2G low memory)"
1114 bool "1G/3G user/kernel split"
1119 default 0xB0000000 if VMSPLIT_3G_OPT
1120 default 0x80000000 if VMSPLIT_2G
1121 default 0x78000000 if VMSPLIT_2G_OPT
1122 default 0x40000000 if VMSPLIT_1G
1128 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1131 bool "PAE (Physical Address Extension) Support"
1132 depends on X86_32 && !HIGHMEM4G
1134 PAE is required for NX support, and furthermore enables
1135 larger swapspace support for non-overcommit purposes. It
1136 has the cost of more pagetable lookup overhead, and also
1137 consumes more pagetable space per process.
1139 config ARCH_PHYS_ADDR_T_64BIT
1140 def_bool X86_64 || X86_PAE
1142 config ARCH_DMA_ADDR_T_64BIT
1143 def_bool X86_64 || HIGHMEM64G
1145 config DIRECT_GBPAGES
1146 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1150 Allow the kernel linear mapping to use 1GB pages on CPUs that
1151 support it. This can improve the kernel's performance a tiny bit by
1152 reducing TLB pressure. If in doubt, say "Y".
1154 # Common NUMA Features
1156 bool "Numa Memory Allocation and Scheduler Support"
1158 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && BROKEN)
1159 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1161 Enable NUMA (Non Uniform Memory Access) support.
1163 The kernel will try to allocate memory used by a CPU on the
1164 local memory controller of the CPU and add some more
1165 NUMA awareness to the kernel.
1167 For 64-bit this is recommended if the system is Intel Core i7
1168 (or later), AMD Opteron, or EM64T NUMA.
1170 For 32-bit this is only needed on (rare) 32-bit-only platforms
1171 that support NUMA topologies, such as NUMAQ / Summit, or if you
1172 boot a 32-bit kernel on a 64-bit NUMA platform.
1174 Otherwise, you should say N.
1176 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1177 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1181 prompt "Old style AMD Opteron NUMA detection"
1182 depends on X86_64 && NUMA && PCI
1184 Enable AMD NUMA node topology detection. You should say Y here if
1185 you have a multi processor AMD system. This uses an old method to
1186 read the NUMA configuration directly from the builtin Northbridge
1187 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1188 which also takes priority if both are compiled in.
1190 config X86_64_ACPI_NUMA
1192 prompt "ACPI NUMA detection"
1193 depends on X86_64 && NUMA && ACPI && PCI
1196 Enable ACPI SRAT based node topology detection.
1198 # Some NUMA nodes have memory ranges that span
1199 # other nodes. Even though a pfn is valid and
1200 # between a node's start and end pfns, it may not
1201 # reside on that node. See memmap_init_zone()
1203 config NODES_SPAN_OTHER_NODES
1205 depends on X86_64_ACPI_NUMA
1208 bool "NUMA emulation"
1211 Enable NUMA emulation. A flat machine will be split
1212 into virtual nodes when booted with "numa=fake=N", where N is the
1213 number of nodes. This is only useful for debugging.
1216 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1218 default "10" if MAXSMP
1219 default "6" if X86_64
1220 default "4" if X86_NUMAQ
1222 depends on NEED_MULTIPLE_NODES
1224 Specify the maximum number of NUMA Nodes available on the target
1225 system. Increases memory reserved to accommodate various tables.
1227 config HAVE_ARCH_BOOTMEM
1229 depends on X86_32 && NUMA
1231 config HAVE_ARCH_ALLOC_REMAP
1233 depends on X86_32 && NUMA
1235 config ARCH_HAVE_MEMORY_PRESENT
1237 depends on X86_32 && DISCONTIGMEM
1239 config NEED_NODE_MEMMAP_SIZE
1241 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1243 config ARCH_FLATMEM_ENABLE
1245 depends on X86_32 && !NUMA
1247 config ARCH_DISCONTIGMEM_ENABLE
1249 depends on NUMA && X86_32
1251 config ARCH_DISCONTIGMEM_DEFAULT
1253 depends on NUMA && X86_32
1255 config ARCH_SPARSEMEM_ENABLE
1257 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1258 select SPARSEMEM_STATIC if X86_32
1259 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1261 config ARCH_SPARSEMEM_DEFAULT
1265 config ARCH_SELECT_MEMORY_MODEL
1267 depends on ARCH_SPARSEMEM_ENABLE
1269 config ARCH_MEMORY_PROBE
1271 depends on MEMORY_HOTPLUG
1273 config ARCH_PROC_KCORE_TEXT
1275 depends on X86_64 && PROC_KCORE
1277 config ILLEGAL_POINTER_VALUE
1280 default 0xdead000000000000 if X86_64
1285 bool "Allocate 3rd-level pagetables from highmem"
1288 The VM uses one page table entry for each page of physical memory.
1289 For systems with a lot of RAM, this can be wasteful of precious
1290 low memory. Setting this option will put user-space page table
1291 entries in high memory.
1293 config X86_CHECK_BIOS_CORRUPTION
1294 bool "Check for low memory corruption"
1296 Periodically check for memory corruption in low memory, which
1297 is suspected to be caused by BIOS. Even when enabled in the
1298 configuration, it is disabled at runtime. Enable it by
1299 setting "memory_corruption_check=1" on the kernel command
1300 line. By default it scans the low 64k of memory every 60
1301 seconds; see the memory_corruption_check_size and
1302 memory_corruption_check_period parameters in
1303 Documentation/kernel-parameters.txt to adjust this.
1305 When enabled with the default parameters, this option has
1306 almost no overhead, as it reserves a relatively small amount
1307 of memory and scans it infrequently. It both detects corruption
1308 and prevents it from affecting the running system.
1310 It is, however, intended as a diagnostic tool; if repeatable
1311 BIOS-originated corruption always affects the same memory,
1312 you can use memmap= to prevent the kernel from using that
1315 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1316 bool "Set the default setting of memory_corruption_check"
1317 depends on X86_CHECK_BIOS_CORRUPTION
1320 Set whether the default state of memory_corruption_check is
1323 config X86_RESERVE_LOW
1324 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1328 Specify the amount of low memory to reserve for the BIOS.
1330 The first page contains BIOS data structures that the kernel
1331 must not use, so that page must always be reserved.
1333 By default we reserve the first 64K of physical RAM, as a
1334 number of BIOSes are known to corrupt that memory range
1335 during events such as suspend/resume or monitor cable
1336 insertion, so it must not be used by the kernel.
1338 You can set this to 4 if you are absolutely sure that you
1339 trust the BIOS to get all its memory reservations and usages
1340 right. If you know your BIOS have problems beyond the
1341 default 64K area, you can set this to 640 to avoid using the
1342 entire low memory range.
1344 If you have doubts about the BIOS (e.g. suspend/resume does
1345 not work or there's kernel crashes after certain hardware
1346 hotplug events) then you might want to enable
1347 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1348 typical corruption patterns.
1350 Leave this to the default value of 64 if you are unsure.
1352 config MATH_EMULATION
1354 prompt "Math emulation" if X86_32
1356 Linux can emulate a math coprocessor (used for floating point
1357 operations) if you don't have one. 486DX and Pentium processors have
1358 a math coprocessor built in, 486SX and 386 do not, unless you added
1359 a 487DX or 387, respectively. (The messages during boot time can
1360 give you some hints here ["man dmesg"].) Everyone needs either a
1361 coprocessor or this emulation.
1363 If you don't have a math coprocessor, you need to say Y here; if you
1364 say Y here even though you have a coprocessor, the coprocessor will
1365 be used nevertheless. (This behavior can be changed with the kernel
1366 command line option "no387", which comes handy if your coprocessor
1367 is broken. Try "man bootparam" or see the documentation of your boot
1368 loader (lilo or loadlin) about how to pass options to the kernel at
1369 boot time.) This means that it is a good idea to say Y here if you
1370 intend to use this kernel on different machines.
1372 More information about the internals of the Linux math coprocessor
1373 emulation can be found in <file:arch/x86/math-emu/README>.
1375 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1376 kernel, it won't hurt.
1380 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1382 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1383 the Memory Type Range Registers (MTRRs) may be used to control
1384 processor access to memory ranges. This is most useful if you have
1385 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1386 allows bus write transfers to be combined into a larger transfer
1387 before bursting over the PCI/AGP bus. This can increase performance
1388 of image write operations 2.5 times or more. Saying Y here creates a
1389 /proc/mtrr file which may be used to manipulate your processor's
1390 MTRRs. Typically the X server should use this.
1392 This code has a reasonably generic interface so that similar
1393 control registers on other processors can be easily supported
1396 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1397 Registers (ARRs) which provide a similar functionality to MTRRs. For
1398 these, the ARRs are used to emulate the MTRRs.
1399 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1400 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1401 write-combining. All of these processors are supported by this code
1402 and it makes sense to say Y here if you have one of them.
1404 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1405 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1406 can lead to all sorts of problems, so it's good to say Y here.
1408 You can safely say Y even if your machine doesn't have MTRRs, you'll
1409 just add about 9 KB to your kernel.
1411 See <file:Documentation/x86/mtrr.txt> for more information.
1413 config MTRR_SANITIZER
1415 prompt "MTRR cleanup support"
1418 Convert MTRR layout from continuous to discrete, so X drivers can
1419 add writeback entries.
1421 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1422 The largest mtrr entry size for a continuous block can be set with
1427 config MTRR_SANITIZER_ENABLE_DEFAULT
1428 int "MTRR cleanup enable value (0-1)"
1431 depends on MTRR_SANITIZER
1433 Enable mtrr cleanup default value
1435 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1436 int "MTRR cleanup spare reg num (0-7)"
1439 depends on MTRR_SANITIZER
1441 mtrr cleanup spare entries default, it can be changed via
1442 mtrr_spare_reg_nr=N on the kernel command line.
1446 prompt "x86 PAT support" if EXPERT
1449 Use PAT attributes to setup page level cache control.
1451 PATs are the modern equivalents of MTRRs and are much more
1452 flexible than MTRRs.
1454 Say N here if you see bootup problems (boot crash, boot hang,
1455 spontaneous reboots) or a non-working video driver.
1459 config ARCH_USES_PG_UNCACHED
1465 prompt "x86 architectural random number generator" if EXPERT
1467 Enable the x86 architectural RDRAND instruction
1468 (Intel Bull Mountain technology) to generate random numbers.
1469 If supported, this is a high bandwidth, cryptographically
1470 secure hardware random number generator.
1473 bool "EFI runtime service support"
1476 This enables the kernel to use EFI runtime services that are
1477 available (such as the EFI variable services).
1479 This option is only useful on systems that have EFI firmware.
1480 In addition, you should use the latest ELILO loader available
1481 at <http://elilo.sourceforge.net> in order to take advantage
1482 of EFI runtime services. However, even with this option, the
1483 resultant kernel should continue to boot on existing non-EFI
1488 prompt "Enable seccomp to safely compute untrusted bytecode"
1490 This kernel feature is useful for number crunching applications
1491 that may need to compute untrusted bytecode during their
1492 execution. By using pipes or other transports made available to
1493 the process as file descriptors supporting the read/write
1494 syscalls, it's possible to isolate those applications in
1495 their own address space using seccomp. Once seccomp is
1496 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1497 and the task is only allowed to execute a few safe syscalls
1498 defined by each seccomp mode.
1500 If unsure, say Y. Only embedded should say N here.
1502 config CC_STACKPROTECTOR
1503 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1505 This option turns on the -fstack-protector GCC feature. This
1506 feature puts, at the beginning of functions, a canary value on
1507 the stack just before the return address, and validates
1508 the value just before actually returning. Stack based buffer
1509 overflows (that need to overwrite this return address) now also
1510 overwrite the canary, which gets detected and the attack is then
1511 neutralized via a kernel panic.
1513 This feature requires gcc version 4.2 or above, or a distribution
1514 gcc with the feature backported. Older versions are automatically
1515 detected and for those versions, this configuration option is
1516 ignored. (and a warning is printed during bootup)
1518 source kernel/Kconfig.hz
1521 bool "kexec system call"
1523 kexec is a system call that implements the ability to shutdown your
1524 current kernel, and to start another kernel. It is like a reboot
1525 but it is independent of the system firmware. And like a reboot
1526 you can start any kernel with it, not just Linux.
1528 The name comes from the similarity to the exec system call.
1530 It is an ongoing process to be certain the hardware in a machine
1531 is properly shutdown, so do not be surprised if this code does not
1532 initially work for you. It may help to enable device hotplugging
1533 support. As of this writing the exact hardware interface is
1534 strongly in flux, so no good recommendation can be made.
1537 bool "kernel crash dumps"
1538 depends on X86_64 || (X86_32 && HIGHMEM)
1540 Generate crash dump after being started by kexec.
1541 This should be normally only set in special crash dump kernels
1542 which are loaded in the main kernel with kexec-tools into
1543 a specially reserved region and then later executed after
1544 a crash by kdump/kexec. The crash dump kernel must be compiled
1545 to a memory address not used by the main kernel or BIOS using
1546 PHYSICAL_START, or it must be built as a relocatable image
1547 (CONFIG_RELOCATABLE=y).
1548 For more details see Documentation/kdump/kdump.txt
1551 bool "kexec jump (EXPERIMENTAL)"
1552 depends on EXPERIMENTAL
1553 depends on KEXEC && HIBERNATION
1555 Jump between original kernel and kexeced kernel and invoke
1556 code in physical address mode via KEXEC
1558 config PHYSICAL_START
1559 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1562 This gives the physical address where the kernel is loaded.
1564 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1565 bzImage will decompress itself to above physical address and
1566 run from there. Otherwise, bzImage will run from the address where
1567 it has been loaded by the boot loader and will ignore above physical
1570 In normal kdump cases one does not have to set/change this option
1571 as now bzImage can be compiled as a completely relocatable image
1572 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1573 address. This option is mainly useful for the folks who don't want
1574 to use a bzImage for capturing the crash dump and want to use a
1575 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1576 to be specifically compiled to run from a specific memory area
1577 (normally a reserved region) and this option comes handy.
1579 So if you are using bzImage for capturing the crash dump,
1580 leave the value here unchanged to 0x1000000 and set
1581 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1582 for capturing the crash dump change this value to start of
1583 the reserved region. In other words, it can be set based on
1584 the "X" value as specified in the "crashkernel=YM@XM"
1585 command line boot parameter passed to the panic-ed
1586 kernel. Please take a look at Documentation/kdump/kdump.txt
1587 for more details about crash dumps.
1589 Usage of bzImage for capturing the crash dump is recommended as
1590 one does not have to build two kernels. Same kernel can be used
1591 as production kernel and capture kernel. Above option should have
1592 gone away after relocatable bzImage support is introduced. But it
1593 is present because there are users out there who continue to use
1594 vmlinux for dump capture. This option should go away down the
1597 Don't change this unless you know what you are doing.
1600 bool "Build a relocatable kernel"
1603 This builds a kernel image that retains relocation information
1604 so it can be loaded someplace besides the default 1MB.
1605 The relocations tend to make the kernel binary about 10% larger,
1606 but are discarded at runtime.
1608 One use is for the kexec on panic case where the recovery kernel
1609 must live at a different physical address than the primary
1612 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1613 it has been loaded at and the compile time physical address
1614 (CONFIG_PHYSICAL_START) is ignored.
1616 # Relocation on x86-32 needs some additional build support
1617 config X86_NEED_RELOCS
1619 depends on X86_32 && RELOCATABLE
1621 config PHYSICAL_ALIGN
1622 hex "Alignment value to which kernel should be aligned" if X86_32
1624 range 0x2000 0x1000000
1626 This value puts the alignment restrictions on physical address
1627 where kernel is loaded and run from. Kernel is compiled for an
1628 address which meets above alignment restriction.
1630 If bootloader loads the kernel at a non-aligned address and
1631 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1632 address aligned to above value and run from there.
1634 If bootloader loads the kernel at a non-aligned address and
1635 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1636 load address and decompress itself to the address it has been
1637 compiled for and run from there. The address for which kernel is
1638 compiled already meets above alignment restrictions. Hence the
1639 end result is that kernel runs from a physical address meeting
1640 above alignment restrictions.
1642 Don't change this unless you know what you are doing.
1645 bool "Support for hot-pluggable CPUs"
1646 depends on SMP && HOTPLUG
1648 Say Y here to allow turning CPUs off and on. CPUs can be
1649 controlled through /sys/devices/system/cpu.
1650 ( Note: power management support will enable this option
1651 automatically on SMP systems. )
1652 Say N if you want to disable CPU hotplug.
1656 prompt "Compat VDSO support"
1657 depends on X86_32 || IA32_EMULATION
1659 Map the 32-bit VDSO to the predictable old-style address too.
1661 Say N here if you are running a sufficiently recent glibc
1662 version (2.3.3 or later), to remove the high-mapped
1663 VDSO mapping and to exclusively use the randomized VDSO.
1668 bool "Built-in kernel command line"
1670 Allow for specifying boot arguments to the kernel at
1671 build time. On some systems (e.g. embedded ones), it is
1672 necessary or convenient to provide some or all of the
1673 kernel boot arguments with the kernel itself (that is,
1674 to not rely on the boot loader to provide them.)
1676 To compile command line arguments into the kernel,
1677 set this option to 'Y', then fill in the
1678 the boot arguments in CONFIG_CMDLINE.
1680 Systems with fully functional boot loaders (i.e. non-embedded)
1681 should leave this option set to 'N'.
1684 string "Built-in kernel command string"
1685 depends on CMDLINE_BOOL
1688 Enter arguments here that should be compiled into the kernel
1689 image and used at boot time. If the boot loader provides a
1690 command line at boot time, it is appended to this string to
1691 form the full kernel command line, when the system boots.
1693 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1694 change this behavior.
1696 In most cases, the command line (whether built-in or provided
1697 by the boot loader) should specify the device for the root
1700 config CMDLINE_OVERRIDE
1701 bool "Built-in command line overrides boot loader arguments"
1702 depends on CMDLINE_BOOL
1704 Set this option to 'Y' to have the kernel ignore the boot loader
1705 command line, and use ONLY the built-in command line.
1707 This is used to work around broken boot loaders. This should
1708 be set to 'N' under normal conditions.
1712 config ARCH_ENABLE_MEMORY_HOTPLUG
1714 depends on X86_64 || (X86_32 && HIGHMEM)
1716 config ARCH_ENABLE_MEMORY_HOTREMOVE
1718 depends on MEMORY_HOTPLUG
1720 config USE_PERCPU_NUMA_NODE_ID
1724 menu "Power management and ACPI options"
1726 config ARCH_HIBERNATION_HEADER
1728 depends on X86_64 && HIBERNATION
1730 source "kernel/power/Kconfig"
1732 source "drivers/acpi/Kconfig"
1734 source "drivers/sfi/Kconfig"
1738 depends on APM || APM_MODULE
1741 tristate "APM (Advanced Power Management) BIOS support"
1742 depends on X86_32 && PM_SLEEP
1744 APM is a BIOS specification for saving power using several different
1745 techniques. This is mostly useful for battery powered laptops with
1746 APM compliant BIOSes. If you say Y here, the system time will be
1747 reset after a RESUME operation, the /proc/apm device will provide
1748 battery status information, and user-space programs will receive
1749 notification of APM "events" (e.g. battery status change).
1751 If you select "Y" here, you can disable actual use of the APM
1752 BIOS by passing the "apm=off" option to the kernel at boot time.
1754 Note that the APM support is almost completely disabled for
1755 machines with more than one CPU.
1757 In order to use APM, you will need supporting software. For location
1758 and more information, read <file:Documentation/power/apm-acpi.txt>
1759 and the Battery Powered Linux mini-HOWTO, available from
1760 <http://www.tldp.org/docs.html#howto>.
1762 This driver does not spin down disk drives (see the hdparm(8)
1763 manpage ("man 8 hdparm") for that), and it doesn't turn off
1764 VESA-compliant "green" monitors.
1766 This driver does not support the TI 4000M TravelMate and the ACER
1767 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1768 desktop machines also don't have compliant BIOSes, and this driver
1769 may cause those machines to panic during the boot phase.
1771 Generally, if you don't have a battery in your machine, there isn't
1772 much point in using this driver and you should say N. If you get
1773 random kernel OOPSes or reboots that don't seem to be related to
1774 anything, try disabling/enabling this option (or disabling/enabling
1777 Some other things you should try when experiencing seemingly random,
1780 1) make sure that you have enough swap space and that it is
1782 2) pass the "no-hlt" option to the kernel
1783 3) switch on floating point emulation in the kernel and pass
1784 the "no387" option to the kernel
1785 4) pass the "floppy=nodma" option to the kernel
1786 5) pass the "mem=4M" option to the kernel (thereby disabling
1787 all but the first 4 MB of RAM)
1788 6) make sure that the CPU is not over clocked.
1789 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1790 8) disable the cache from your BIOS settings
1791 9) install a fan for the video card or exchange video RAM
1792 10) install a better fan for the CPU
1793 11) exchange RAM chips
1794 12) exchange the motherboard.
1796 To compile this driver as a module, choose M here: the
1797 module will be called apm.
1801 config APM_IGNORE_USER_SUSPEND
1802 bool "Ignore USER SUSPEND"
1804 This option will ignore USER SUSPEND requests. On machines with a
1805 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1806 series notebooks, it is necessary to say Y because of a BIOS bug.
1808 config APM_DO_ENABLE
1809 bool "Enable PM at boot time"
1811 Enable APM features at boot time. From page 36 of the APM BIOS
1812 specification: "When disabled, the APM BIOS does not automatically
1813 power manage devices, enter the Standby State, enter the Suspend
1814 State, or take power saving steps in response to CPU Idle calls."
1815 This driver will make CPU Idle calls when Linux is idle (unless this
1816 feature is turned off -- see "Do CPU IDLE calls", below). This
1817 should always save battery power, but more complicated APM features
1818 will be dependent on your BIOS implementation. You may need to turn
1819 this option off if your computer hangs at boot time when using APM
1820 support, or if it beeps continuously instead of suspending. Turn
1821 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1822 T400CDT. This is off by default since most machines do fine without
1826 bool "Make CPU Idle calls when idle"
1828 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1829 On some machines, this can activate improved power savings, such as
1830 a slowed CPU clock rate, when the machine is idle. These idle calls
1831 are made after the idle loop has run for some length of time (e.g.,
1832 333 mS). On some machines, this will cause a hang at boot time or
1833 whenever the CPU becomes idle. (On machines with more than one CPU,
1834 this option does nothing.)
1836 config APM_DISPLAY_BLANK
1837 bool "Enable console blanking using APM"
1839 Enable console blanking using the APM. Some laptops can use this to
1840 turn off the LCD backlight when the screen blanker of the Linux
1841 virtual console blanks the screen. Note that this is only used by
1842 the virtual console screen blanker, and won't turn off the backlight
1843 when using the X Window system. This also doesn't have anything to
1844 do with your VESA-compliant power-saving monitor. Further, this
1845 option doesn't work for all laptops -- it might not turn off your
1846 backlight at all, or it might print a lot of errors to the console,
1847 especially if you are using gpm.
1849 config APM_ALLOW_INTS
1850 bool "Allow interrupts during APM BIOS calls"
1852 Normally we disable external interrupts while we are making calls to
1853 the APM BIOS as a measure to lessen the effects of a badly behaving
1854 BIOS implementation. The BIOS should reenable interrupts if it
1855 needs to. Unfortunately, some BIOSes do not -- especially those in
1856 many of the newer IBM Thinkpads. If you experience hangs when you
1857 suspend, try setting this to Y. Otherwise, say N.
1861 source "drivers/cpufreq/Kconfig"
1863 source "drivers/cpuidle/Kconfig"
1865 source "drivers/idle/Kconfig"
1870 menu "Bus options (PCI etc.)"
1875 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1877 Find out whether you have a PCI motherboard. PCI is the name of a
1878 bus system, i.e. the way the CPU talks to the other stuff inside
1879 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1880 VESA. If you have PCI, say Y, otherwise N.
1883 prompt "PCI access mode"
1884 depends on X86_32 && PCI
1887 On PCI systems, the BIOS can be used to detect the PCI devices and
1888 determine their configuration. However, some old PCI motherboards
1889 have BIOS bugs and may crash if this is done. Also, some embedded
1890 PCI-based systems don't have any BIOS at all. Linux can also try to
1891 detect the PCI hardware directly without using the BIOS.
1893 With this option, you can specify how Linux should detect the
1894 PCI devices. If you choose "BIOS", the BIOS will be used,
1895 if you choose "Direct", the BIOS won't be used, and if you
1896 choose "MMConfig", then PCI Express MMCONFIG will be used.
1897 If you choose "Any", the kernel will try MMCONFIG, then the
1898 direct access method and falls back to the BIOS if that doesn't
1899 work. If unsure, go with the default, which is "Any".
1904 config PCI_GOMMCONFIG
1921 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1923 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1926 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1930 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1934 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1938 depends on PCI && XEN
1946 bool "Support mmconfig PCI config space access"
1947 depends on X86_64 && PCI && ACPI
1949 config PCI_CNB20LE_QUIRK
1950 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1952 depends on PCI && EXPERIMENTAL
1954 Read the PCI windows out of the CNB20LE host bridge. This allows
1955 PCI hotplug to work on systems with the CNB20LE chipset which do
1958 There's no public spec for this chipset, and this functionality
1959 is known to be incomplete.
1961 You should say N unless you know you need this.
1963 source "drivers/pci/pcie/Kconfig"
1965 source "drivers/pci/Kconfig"
1967 # x86_64 have no ISA slots, but can have ISA-style DMA.
1969 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1972 Enables ISA-style DMA support for devices requiring such controllers.
1980 Find out whether you have ISA slots on your motherboard. ISA is the
1981 name of a bus system, i.e. the way the CPU talks to the other stuff
1982 inside your box. Other bus systems are PCI, EISA, MicroChannel
1983 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1984 newer boards don't support it. If you have ISA, say Y, otherwise N.
1990 The Extended Industry Standard Architecture (EISA) bus was
1991 developed as an open alternative to the IBM MicroChannel bus.
1993 The EISA bus provided some of the features of the IBM MicroChannel
1994 bus while maintaining backward compatibility with cards made for
1995 the older ISA bus. The EISA bus saw limited use between 1988 and
1996 1995 when it was made obsolete by the PCI bus.
1998 Say Y here if you are building a kernel for an EISA-based machine.
2002 source "drivers/eisa/Kconfig"
2007 MicroChannel Architecture is found in some IBM PS/2 machines and
2008 laptops. It is a bus system similar to PCI or ISA. See
2009 <file:Documentation/mca.txt> (and especially the web page given
2010 there) before attempting to build an MCA bus kernel.
2012 source "drivers/mca/Kconfig"
2015 tristate "NatSemi SCx200 support"
2017 This provides basic support for National Semiconductor's
2018 (now AMD's) Geode processors. The driver probes for the
2019 PCI-IDs of several on-chip devices, so its a good dependency
2020 for other scx200_* drivers.
2022 If compiled as a module, the driver is named scx200.
2024 config SCx200HR_TIMER
2025 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2029 This driver provides a clocksource built upon the on-chip
2030 27MHz high-resolution timer. Its also a workaround for
2031 NSC Geode SC-1100's buggy TSC, which loses time when the
2032 processor goes idle (as is done by the scheduler). The
2033 other workaround is idle=poll boot option.
2036 bool "One Laptop Per Child support"
2042 Add support for detecting the unique features of the OLPC
2046 bool "OLPC XO-1 Power Management"
2047 depends on OLPC && MFD_CS5535 && PM_SLEEP
2050 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2053 bool "OLPC XO-1 Real Time Clock"
2054 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2056 Add support for the XO-1 real time clock, which can be used as a
2057 programmable wakeup source.
2060 bool "OLPC XO-1 SCI extras"
2061 depends on OLPC && OLPC_XO1_PM
2066 Add support for SCI-based features of the OLPC XO-1 laptop:
2067 - EC-driven system wakeups
2071 - AC adapter status updates
2072 - Battery status updates
2074 config OLPC_XO15_SCI
2075 bool "OLPC XO-1.5 SCI extras"
2076 depends on OLPC && ACPI
2079 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2080 - EC-driven system wakeups
2081 - AC adapter status updates
2082 - Battery status updates
2085 bool "PCEngines ALIX System Support (LED setup)"
2088 This option enables system support for the PCEngines ALIX.
2089 At present this just sets up LEDs for GPIO control on
2090 ALIX2/3/6 boards. However, other system specific setup should
2093 Note: You must still enable the drivers for GPIO and LED support
2094 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2096 Note: You have to set alix.force=1 for boards with Award BIOS.
2102 depends on CPU_SUP_AMD && PCI
2104 source "drivers/pcmcia/Kconfig"
2106 source "drivers/pci/hotplug/Kconfig"
2109 bool "RapidIO support"
2113 If you say Y here, the kernel will include drivers and
2114 infrastructure code to support RapidIO interconnect devices.
2116 source "drivers/rapidio/Kconfig"
2121 menu "Executable file formats / Emulations"
2123 source "fs/Kconfig.binfmt"
2125 config IA32_EMULATION
2126 bool "IA32 Emulation"
2129 select COMPAT_BINFMT_ELF
2131 Include code to run 32-bit programs under a 64-bit kernel. You should
2132 likely turn this on, unless you're 100% sure that you don't have any
2133 32-bit programs left.
2136 tristate "IA32 a.out support"
2137 depends on IA32_EMULATION
2139 Support old a.out binaries in the 32bit emulation.
2143 depends on IA32_EMULATION
2145 config COMPAT_FOR_U64_ALIGNMENT
2149 config SYSVIPC_COMPAT
2151 depends on COMPAT && SYSVIPC
2155 depends on COMPAT && KEYS
2161 config HAVE_ATOMIC_IOMAP
2165 config HAVE_TEXT_POKE_SMP
2167 select STOP_MACHINE if SMP
2169 source "net/Kconfig"
2171 source "drivers/Kconfig"
2173 source "drivers/firmware/Kconfig"
2177 source "arch/x86/Kconfig.debug"
2179 source "security/Kconfig"
2181 source "crypto/Kconfig"
2183 source "arch/x86/kvm/Kconfig"
2185 source "lib/Kconfig"