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
81 select ARCH_HAVE_NMI_SAFE_CMPXCHG
83 select DCACHE_WORD_ACCESS
84 select GENERIC_SMP_IDLE_THREAD
85 select HAVE_ARCH_SECCOMP_FILTER
87 config INSTRUCTION_DECODER
88 def_bool (KPROBES || PERF_EVENTS)
92 default "elf32-i386" if X86_32
93 default "elf64-x86-64" if X86_64
97 default "arch/x86/configs/i386_defconfig" if X86_32
98 default "arch/x86/configs/x86_64_defconfig" if X86_64
100 config GENERIC_CMOS_UPDATE
103 config CLOCKSOURCE_WATCHDOG
106 config GENERIC_CLOCKEVENTS
109 config ARCH_CLOCKSOURCE_DATA
113 config GENERIC_CLOCKEVENTS_BROADCAST
115 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
117 config LOCKDEP_SUPPORT
120 config STACKTRACE_SUPPORT
123 config HAVE_LATENCYTOP_SUPPORT
132 config NEED_DMA_MAP_STATE
133 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
135 config NEED_SG_DMA_LENGTH
138 config GENERIC_ISA_DMA
144 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
146 config GENERIC_BUG_RELATIVE_POINTERS
149 config GENERIC_HWEIGHT
155 config ARCH_MAY_HAVE_PC_FDC
158 config RWSEM_GENERIC_SPINLOCK
161 config RWSEM_XCHGADD_ALGORITHM
164 config GENERIC_CALIBRATE_DELAY
167 config GENERIC_TIME_VSYSCALL
171 config ARCH_HAS_CPU_RELAX
174 config ARCH_HAS_DEFAULT_IDLE
177 config ARCH_HAS_CACHE_LINE_SIZE
180 config ARCH_HAS_CPU_AUTOPROBE
183 config HAVE_SETUP_PER_CPU_AREA
186 config NEED_PER_CPU_EMBED_FIRST_CHUNK
189 config NEED_PER_CPU_PAGE_FIRST_CHUNK
192 config ARCH_HIBERNATION_POSSIBLE
195 config ARCH_SUSPEND_POSSIBLE
206 config ARCH_SUPPORTS_OPTIMIZED_INLINING
209 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
212 config HAVE_INTEL_TXT
214 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
218 depends on X86_32 && SMP
222 depends on X86_64 && SMP
228 config X86_32_LAZY_GS
230 depends on X86_32 && !CC_STACKPROTECTOR
232 config ARCH_HWEIGHT_CFLAGS
234 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
235 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
240 config ARCH_CPU_PROBE_RELEASE
242 depends on HOTPLUG_CPU
244 source "init/Kconfig"
245 source "kernel/Kconfig.freezer"
247 menu "Processor type and features"
250 bool "DMA memory allocation support" if EXPERT
253 DMA memory allocation support allows devices with less than 32-bit
254 addressing to allocate within the first 16MB of address space.
255 Disable if no such devices will be used.
259 source "kernel/time/Kconfig"
262 bool "Symmetric multi-processing support"
264 This enables support for systems with more than one CPU. If you have
265 a system with only one CPU, like most personal computers, say N. If
266 you have a system with more than one CPU, say Y.
268 If you say N here, the kernel will run on single and multiprocessor
269 machines, but will use only one CPU of a multiprocessor machine. If
270 you say Y here, the kernel will run on many, but not all,
271 singleprocessor machines. On a singleprocessor machine, the kernel
272 will run faster if you say N here.
274 Note that if you say Y here and choose architecture "586" or
275 "Pentium" under "Processor family", the kernel will not work on 486
276 architectures. Similarly, multiprocessor kernels for the "PPro"
277 architecture may not work on all Pentium based boards.
279 People using multiprocessor machines who say Y here should also say
280 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
281 Management" code will be disabled if you say Y here.
283 See also <file:Documentation/x86/i386/IO-APIC.txt>,
284 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
285 <http://www.tldp.org/docs.html#howto>.
287 If you don't know what to do here, say N.
290 bool "Support x2apic"
291 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
293 This enables x2apic support on CPUs that have this feature.
295 This allows 32-bit apic IDs (so it can support very large systems),
296 and accesses the local apic via MSRs not via mmio.
298 If you don't know what to do here, say N.
301 bool "Enable MPS table" if ACPI
303 depends on X86_LOCAL_APIC
305 For old smp systems that do not have proper acpi support. Newer systems
306 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
309 bool "Support for big SMP systems with more than 8 CPUs"
310 depends on X86_32 && SMP
312 This option is needed for the systems that have more than 8 CPUs
315 config X86_EXTENDED_PLATFORM
316 bool "Support for extended (non-PC) x86 platforms"
319 If you disable this option then the kernel will only support
320 standard PC platforms. (which covers the vast majority of
323 If you enable this option then you'll be able to select support
324 for the following (non-PC) 32 bit x86 platforms:
328 SGI 320/540 (Visual Workstation)
329 Summit/EXA (IBM x440)
330 Unisys ES7000 IA32 series
331 Moorestown MID devices
333 If you have one of these systems, or if you want to build a
334 generic distribution kernel, say Y here - otherwise say N.
338 config X86_EXTENDED_PLATFORM
339 bool "Support for extended (non-PC) x86 platforms"
342 If you disable this option then the kernel will only support
343 standard PC platforms. (which covers the vast majority of
346 If you enable this option then you'll be able to select support
347 for the following (non-PC) 64 bit x86 platforms:
352 If you have one of these systems, or if you want to build a
353 generic distribution kernel, say Y here - otherwise say N.
355 # This is an alphabetically sorted list of 64 bit extended platforms
356 # Please maintain the alphabetic order if and when there are additions
358 bool "Numascale NumaChip"
360 depends on X86_EXTENDED_PLATFORM
363 depends on X86_X2APIC
365 Adds support for Numascale NumaChip large-SMP systems. Needed to
366 enable more than ~168 cores.
367 If you don't have one of these, you should say N here.
371 select PARAVIRT_GUEST
373 depends on X86_64 && PCI
374 depends on X86_EXTENDED_PLATFORM
376 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
377 supposed to run on these EM64T-based machines. Only choose this option
378 if you have one of these machines.
381 bool "SGI Ultraviolet"
383 depends on X86_EXTENDED_PLATFORM
385 depends on X86_X2APIC
387 This option is needed in order to support SGI Ultraviolet systems.
388 If you don't have one of these, you should say N here.
390 # Following is an alphabetically sorted list of 32 bit extended platforms
391 # Please maintain the alphabetic order if and when there are additions
394 bool "CE4100 TV platform"
396 depends on PCI_GODIRECT
398 depends on X86_EXTENDED_PLATFORM
399 select X86_REBOOTFIXUPS
401 select OF_EARLY_FLATTREE
404 Select for the Intel CE media processor (CE4100) SOC.
405 This option compiles in support for the CE4100 SOC for settop
406 boxes and media devices.
408 config X86_WANT_INTEL_MID
409 bool "Intel MID platform support"
411 depends on X86_EXTENDED_PLATFORM
413 Select to build a kernel capable of supporting Intel MID platform
414 systems which do not have the PCI legacy interfaces (Moorestown,
415 Medfield). If you are building for a PC class system say N here.
417 if X86_WANT_INTEL_MID
423 bool "Medfield MID platform"
426 depends on X86_IO_APIC
434 select X86_PLATFORM_DEVICES
435 select MFD_INTEL_MSIC
437 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
438 Internet Device(MID) platform.
439 Unlike standard x86 PCs, Medfield does not have many legacy devices
440 nor standard legacy replacement devices/features. e.g. Medfield does
441 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
446 bool "RDC R-321x SoC"
448 depends on X86_EXTENDED_PLATFORM
450 select X86_REBOOTFIXUPS
452 This option is needed for RDC R-321x system-on-chip, also known
454 If you don't have one of these chips, you should say N here.
456 config X86_32_NON_STANDARD
457 bool "Support non-standard 32-bit SMP architectures"
458 depends on X86_32 && SMP
459 depends on X86_EXTENDED_PLATFORM
461 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
462 subarchitectures. It is intended for a generic binary kernel.
463 if you select them all, kernel will probe it one by one. and will
466 # Alphabetically sorted list of Non standard 32 bit platforms
469 bool "NUMAQ (IBM/Sequent)"
470 depends on X86_32_NON_STANDARD
475 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
476 NUMA multiquad box. This changes the way that processors are
477 bootstrapped, and uses Clustered Logical APIC addressing mode instead
478 of Flat Logical. You will need a new lynxer.elf file to flash your
479 firmware with - send email to <Martin.Bligh@us.ibm.com>.
481 config X86_SUPPORTS_MEMORY_FAILURE
483 # MCE code calls memory_failure():
485 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
486 depends on !X86_NUMAQ
487 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
488 depends on X86_64 || !SPARSEMEM
489 select ARCH_SUPPORTS_MEMORY_FAILURE
492 bool "SGI 320/540 (Visual Workstation)"
493 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
494 depends on X86_32_NON_STANDARD
496 The SGI Visual Workstation series is an IA32-based workstation
497 based on SGI systems chips with some legacy PC hardware attached.
499 Say Y here to create a kernel to run on the SGI 320 or 540.
501 A kernel compiled for the Visual Workstation will run on general
502 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
505 bool "Summit/EXA (IBM x440)"
506 depends on X86_32_NON_STANDARD
508 This option is needed for IBM systems that use the Summit/EXA chipset.
509 In particular, it is needed for the x440.
512 bool "Unisys ES7000 IA32 series"
513 depends on X86_32_NON_STANDARD && X86_BIGSMP
515 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
516 supposed to run on an IA32-based Unisys ES7000 system.
519 tristate "Eurobraille/Iris poweroff module"
522 The Iris machines from EuroBraille do not have APM or ACPI support
523 to shut themselves down properly. A special I/O sequence is
524 needed to do so, which is what this module does at
527 This is only for Iris machines from EuroBraille.
531 config SCHED_OMIT_FRAME_POINTER
533 prompt "Single-depth WCHAN output"
536 Calculate simpler /proc/<PID>/wchan values. If this option
537 is disabled then wchan values will recurse back to the
538 caller function. This provides more accurate wchan values,
539 at the expense of slightly more scheduling overhead.
541 If in doubt, say "Y".
543 menuconfig PARAVIRT_GUEST
544 bool "Paravirtualized guest support"
546 Say Y here to get to see options related to running Linux under
547 various hypervisors. This option alone does not add any kernel code.
549 If you say N, all options in this submenu will be skipped and disabled.
553 config PARAVIRT_TIME_ACCOUNTING
554 bool "Paravirtual steal time accounting"
558 Select this option to enable fine granularity task steal time
559 accounting. Time spent executing other tasks in parallel with
560 the current vCPU is discounted from the vCPU power. To account for
561 that, there can be a small performance impact.
563 If in doubt, say N here.
565 source "arch/x86/xen/Kconfig"
568 bool "KVM paravirtualized clock"
570 select PARAVIRT_CLOCK
572 Turning on this option will allow you to run a paravirtualized clock
573 when running over the KVM hypervisor. Instead of relying on a PIT
574 (or probably other) emulation by the underlying device model, the host
575 provides the guest with timing infrastructure such as time of day, and
579 bool "KVM Guest support"
582 This option enables various optimizations for running under the KVM
585 source "arch/x86/lguest/Kconfig"
588 bool "Enable paravirtualization code"
590 This changes the kernel so it can modify itself when it is run
591 under a hypervisor, potentially improving performance significantly
592 over full virtualization. However, when run without a hypervisor
593 the kernel is theoretically slower and slightly larger.
595 config PARAVIRT_SPINLOCKS
596 bool "Paravirtualization layer for spinlocks"
597 depends on PARAVIRT && SMP && EXPERIMENTAL
599 Paravirtualized spinlocks allow a pvops backend to replace the
600 spinlock implementation with something virtualization-friendly
601 (for example, block the virtual CPU rather than spinning).
603 Unfortunately the downside is an up to 5% performance hit on
604 native kernels, with various workloads.
606 If you are unsure how to answer this question, answer N.
608 config PARAVIRT_CLOCK
613 config PARAVIRT_DEBUG
614 bool "paravirt-ops debugging"
615 depends on PARAVIRT && DEBUG_KERNEL
617 Enable to debug paravirt_ops internals. Specifically, BUG if
618 a paravirt_op is missing when it is called.
626 This option adds a kernel parameter 'memtest', which allows memtest
628 memtest=0, mean disabled; -- default
629 memtest=1, mean do 1 test pattern;
631 memtest=4, mean do 4 test patterns.
632 If you are unsure how to answer this question, answer N.
634 config X86_SUMMIT_NUMA
636 depends on X86_32 && NUMA && X86_32_NON_STANDARD
638 config X86_CYCLONE_TIMER
640 depends on X86_SUMMIT
642 source "arch/x86/Kconfig.cpu"
646 prompt "HPET Timer Support" if X86_32
648 Use the IA-PC HPET (High Precision Event Timer) to manage
649 time in preference to the PIT and RTC, if a HPET is
651 HPET is the next generation timer replacing legacy 8254s.
652 The HPET provides a stable time base on SMP
653 systems, unlike the TSC, but it is more expensive to access,
654 as it is off-chip. You can find the HPET spec at
655 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
657 You can safely choose Y here. However, HPET will only be
658 activated if the platform and the BIOS support this feature.
659 Otherwise the 8254 will be used for timing services.
661 Choose N to continue using the legacy 8254 timer.
663 config HPET_EMULATE_RTC
665 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
668 def_bool y if X86_INTEL_MID
669 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
671 depends on X86_INTEL_MID && SFI
673 APB timer is the replacement for 8254, HPET on X86 MID platforms.
674 The APBT provides a stable time base on SMP
675 systems, unlike the TSC, but it is more expensive to access,
676 as it is off-chip. APB timers are always running regardless of CPU
677 C states, they are used as per CPU clockevent device when possible.
679 # Mark as expert because too many people got it wrong.
680 # The code disables itself when not needed.
683 bool "Enable DMI scanning" if EXPERT
685 Enabled scanning of DMI to identify machine quirks. Say Y
686 here unless you have verified that your setup is not
687 affected by entries in the DMI blacklist. Required by PNP
691 bool "GART IOMMU support" if EXPERT
694 depends on X86_64 && PCI && AMD_NB
696 Support for full DMA access of devices with 32bit memory access only
697 on systems with more than 3GB. This is usually needed for USB,
698 sound, many IDE/SATA chipsets and some other devices.
699 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
700 based hardware IOMMU and a software bounce buffer based IOMMU used
701 on Intel systems and as fallback.
702 The code is only active when needed (enough memory and limited
703 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
707 bool "IBM Calgary IOMMU support"
709 depends on X86_64 && PCI && EXPERIMENTAL
711 Support for hardware IOMMUs in IBM's xSeries x366 and x460
712 systems. Needed to run systems with more than 3GB of memory
713 properly with 32-bit PCI devices that do not support DAC
714 (Double Address Cycle). Calgary also supports bus level
715 isolation, where all DMAs pass through the IOMMU. This
716 prevents them from going anywhere except their intended
717 destination. This catches hard-to-find kernel bugs and
718 mis-behaving drivers and devices that do not use the DMA-API
719 properly to set up their DMA buffers. The IOMMU can be
720 turned off at boot time with the iommu=off parameter.
721 Normally the kernel will make the right choice by itself.
724 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
726 prompt "Should Calgary be enabled by default?"
727 depends on CALGARY_IOMMU
729 Should Calgary be enabled by default? if you choose 'y', Calgary
730 will be used (if it exists). If you choose 'n', Calgary will not be
731 used even if it exists. If you choose 'n' and would like to use
732 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
735 # need this always selected by IOMMU for the VIA workaround
739 Support for software bounce buffers used on x86-64 systems
740 which don't have a hardware IOMMU (e.g. the current generation
741 of Intel's x86-64 CPUs). Using this PCI devices which can only
742 access 32-bits of memory can be used on systems with more than
743 3 GB of memory. If unsure, say Y.
746 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
749 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
750 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
751 select CPUMASK_OFFSTACK
753 Enable maximum number of CPUS and NUMA Nodes for this architecture.
757 int "Maximum number of CPUs" if SMP && !MAXSMP
758 range 2 8 if SMP && X86_32 && !X86_BIGSMP
759 range 2 512 if SMP && !MAXSMP
761 default "4096" if MAXSMP
762 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
765 This allows you to specify the maximum number of CPUs which this
766 kernel will support. The maximum supported value is 512 and the
767 minimum value which makes sense is 2.
769 This is purely to save memory - each supported CPU adds
770 approximately eight kilobytes to the kernel image.
773 bool "SMT (Hyperthreading) scheduler support"
776 SMT scheduler support improves the CPU scheduler's decision making
777 when dealing with Intel Pentium 4 chips with HyperThreading at a
778 cost of slightly increased overhead in some places. If unsure say
783 prompt "Multi-core scheduler support"
786 Multi-core scheduler support improves the CPU scheduler's decision
787 making when dealing with multi-core CPU chips at a cost of slightly
788 increased overhead in some places. If unsure say N here.
790 config IRQ_TIME_ACCOUNTING
791 bool "Fine granularity task level IRQ time accounting"
794 Select this option to enable fine granularity task irq time
795 accounting. This is done by reading a timestamp on each
796 transitions between softirq and hardirq state, so there can be a
797 small performance impact.
799 If in doubt, say N here.
801 source "kernel/Kconfig.preempt"
804 bool "Local APIC support on uniprocessors"
805 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
807 A local APIC (Advanced Programmable Interrupt Controller) is an
808 integrated interrupt controller in the CPU. If you have a single-CPU
809 system which has a processor with a local APIC, you can say Y here to
810 enable and use it. If you say Y here even though your machine doesn't
811 have a local APIC, then the kernel will still run with no slowdown at
812 all. The local APIC supports CPU-generated self-interrupts (timer,
813 performance counters), and the NMI watchdog which detects hard
817 bool "IO-APIC support on uniprocessors"
818 depends on X86_UP_APIC
820 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
821 SMP-capable replacement for PC-style interrupt controllers. Most
822 SMP systems and many recent uniprocessor systems have one.
824 If you have a single-CPU system with an IO-APIC, you can say Y here
825 to use it. If you say Y here even though your machine doesn't have
826 an IO-APIC, then the kernel will still run with no slowdown at all.
828 config X86_LOCAL_APIC
830 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
834 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
836 config X86_VISWS_APIC
838 depends on X86_32 && X86_VISWS
840 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
841 bool "Reroute for broken boot IRQs"
842 depends on X86_IO_APIC
844 This option enables a workaround that fixes a source of
845 spurious interrupts. This is recommended when threaded
846 interrupt handling is used on systems where the generation of
847 superfluous "boot interrupts" cannot be disabled.
849 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
850 entry in the chipset's IO-APIC is masked (as, e.g. the RT
851 kernel does during interrupt handling). On chipsets where this
852 boot IRQ generation cannot be disabled, this workaround keeps
853 the original IRQ line masked so that only the equivalent "boot
854 IRQ" is delivered to the CPUs. The workaround also tells the
855 kernel to set up the IRQ handler on the boot IRQ line. In this
856 way only one interrupt is delivered to the kernel. Otherwise
857 the spurious second interrupt may cause the kernel to bring
858 down (vital) interrupt lines.
860 Only affects "broken" chipsets. Interrupt sharing may be
861 increased on these systems.
864 bool "Machine Check / overheating reporting"
866 Machine Check support allows the processor to notify the
867 kernel if it detects a problem (e.g. overheating, data corruption).
868 The action the kernel takes depends on the severity of the problem,
869 ranging from warning messages to halting the machine.
873 prompt "Intel MCE features"
874 depends on X86_MCE && X86_LOCAL_APIC
876 Additional support for intel specific MCE features such as
881 prompt "AMD MCE features"
882 depends on X86_MCE && X86_LOCAL_APIC
884 Additional support for AMD specific MCE features such as
885 the DRAM Error Threshold.
887 config X86_ANCIENT_MCE
888 bool "Support for old Pentium 5 / WinChip machine checks"
889 depends on X86_32 && X86_MCE
891 Include support for machine check handling on old Pentium 5 or WinChip
892 systems. These typically need to be enabled explicitely on the command
895 config X86_MCE_THRESHOLD
896 depends on X86_MCE_AMD || X86_MCE_INTEL
899 config X86_MCE_INJECT
901 tristate "Machine check injector support"
903 Provide support for injecting machine checks for testing purposes.
904 If you don't know what a machine check is and you don't do kernel
905 QA it is safe to say n.
907 config X86_THERMAL_VECTOR
909 depends on X86_MCE_INTEL
912 bool "Enable VM86 support" if EXPERT
916 This option is required by programs like DOSEMU to run 16-bit legacy
917 code on X86 processors. It also may be needed by software like
918 XFree86 to initialize some video cards via BIOS. Disabling this
919 option saves about 6k.
922 tristate "Toshiba Laptop support"
925 This adds a driver to safely access the System Management Mode of
926 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
927 not work on models with a Phoenix BIOS. The System Management Mode
928 is used to set the BIOS and power saving options on Toshiba portables.
930 For information on utilities to make use of this driver see the
931 Toshiba Linux utilities web site at:
932 <http://www.buzzard.org.uk/toshiba/>.
934 Say Y if you intend to run this kernel on a Toshiba portable.
938 tristate "Dell laptop support"
941 This adds a driver to safely access the System Management Mode
942 of the CPU on the Dell Inspiron 8000. The System Management Mode
943 is used to read cpu temperature and cooling fan status and to
944 control the fans on the I8K portables.
946 This driver has been tested only on the Inspiron 8000 but it may
947 also work with other Dell laptops. You can force loading on other
948 models by passing the parameter `force=1' to the module. Use at
951 For information on utilities to make use of this driver see the
952 I8K Linux utilities web site at:
953 <http://people.debian.org/~dz/i8k/>
955 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
958 config X86_REBOOTFIXUPS
959 bool "Enable X86 board specific fixups for reboot"
962 This enables chipset and/or board specific fixups to be done
963 in order to get reboot to work correctly. This is only needed on
964 some combinations of hardware and BIOS. The symptom, for which
965 this config is intended, is when reboot ends with a stalled/hung
968 Currently, the only fixup is for the Geode machines using
969 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
971 Say Y if you want to enable the fixup. Currently, it's safe to
972 enable this option even if you don't need it.
976 tristate "/dev/cpu/microcode - microcode support"
979 If you say Y here, you will be able to update the microcode on
980 certain Intel and AMD processors. The Intel support is for the
981 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
982 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
983 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
984 You will obviously need the actual microcode binary data itself
985 which is not shipped with the Linux kernel.
987 This option selects the general module only, you need to select
988 at least one vendor specific module as well.
990 To compile this driver as a module, choose M here: the
991 module will be called microcode.
993 config MICROCODE_INTEL
994 bool "Intel microcode patch loading support"
999 This options enables microcode patch loading support for Intel
1002 For latest news and information on obtaining all the required
1003 Intel ingredients for this driver, check:
1004 <http://www.urbanmyth.org/microcode/>.
1006 config MICROCODE_AMD
1007 bool "AMD microcode patch loading support"
1008 depends on MICROCODE
1011 If you select this option, microcode patch loading support for AMD
1012 processors will be enabled.
1014 config MICROCODE_OLD_INTERFACE
1016 depends on MICROCODE
1019 tristate "/dev/cpu/*/msr - Model-specific register support"
1021 This device gives privileged processes access to the x86
1022 Model-Specific Registers (MSRs). It is a character device with
1023 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1024 MSR accesses are directed to a specific CPU on multi-processor
1028 tristate "/dev/cpu/*/cpuid - CPU information support"
1030 This device gives processes access to the x86 CPUID instruction to
1031 be executed on a specific processor. It is a character device
1032 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1036 prompt "High Memory Support"
1037 default HIGHMEM64G if X86_NUMAQ
1043 depends on !X86_NUMAQ
1045 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1046 However, the address space of 32-bit x86 processors is only 4
1047 Gigabytes large. That means that, if you have a large amount of
1048 physical memory, not all of it can be "permanently mapped" by the
1049 kernel. The physical memory that's not permanently mapped is called
1052 If you are compiling a kernel which will never run on a machine with
1053 more than 1 Gigabyte total physical RAM, answer "off" here (default
1054 choice and suitable for most users). This will result in a "3GB/1GB"
1055 split: 3GB are mapped so that each process sees a 3GB virtual memory
1056 space and the remaining part of the 4GB virtual memory space is used
1057 by the kernel to permanently map as much physical memory as
1060 If the machine has between 1 and 4 Gigabytes physical RAM, then
1063 If more than 4 Gigabytes is used then answer "64GB" here. This
1064 selection turns Intel PAE (Physical Address Extension) mode on.
1065 PAE implements 3-level paging on IA32 processors. PAE is fully
1066 supported by Linux, PAE mode is implemented on all recent Intel
1067 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1068 then the kernel will not boot on CPUs that don't support PAE!
1070 The actual amount of total physical memory will either be
1071 auto detected or can be forced by using a kernel command line option
1072 such as "mem=256M". (Try "man bootparam" or see the documentation of
1073 your boot loader (lilo or loadlin) about how to pass options to the
1074 kernel at boot time.)
1076 If unsure, say "off".
1080 depends on !X86_NUMAQ
1082 Select this if you have a 32-bit processor and between 1 and 4
1083 gigabytes of physical RAM.
1087 depends on !M386 && !M486
1090 Select this if you have a 32-bit processor and more than 4
1091 gigabytes of physical RAM.
1096 depends on EXPERIMENTAL
1097 prompt "Memory split" if EXPERT
1101 Select the desired split between kernel and user memory.
1103 If the address range available to the kernel is less than the
1104 physical memory installed, the remaining memory will be available
1105 as "high memory". Accessing high memory is a little more costly
1106 than low memory, as it needs to be mapped into the kernel first.
1107 Note that increasing the kernel address space limits the range
1108 available to user programs, making the address space there
1109 tighter. Selecting anything other than the default 3G/1G split
1110 will also likely make your kernel incompatible with binary-only
1113 If you are not absolutely sure what you are doing, leave this
1117 bool "3G/1G user/kernel split"
1118 config VMSPLIT_3G_OPT
1120 bool "3G/1G user/kernel split (for full 1G low memory)"
1122 bool "2G/2G user/kernel split"
1123 config VMSPLIT_2G_OPT
1125 bool "2G/2G user/kernel split (for full 2G low memory)"
1127 bool "1G/3G user/kernel split"
1132 default 0xB0000000 if VMSPLIT_3G_OPT
1133 default 0x80000000 if VMSPLIT_2G
1134 default 0x78000000 if VMSPLIT_2G_OPT
1135 default 0x40000000 if VMSPLIT_1G
1141 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1144 bool "PAE (Physical Address Extension) Support"
1145 depends on X86_32 && !HIGHMEM4G
1147 PAE is required for NX support, and furthermore enables
1148 larger swapspace support for non-overcommit purposes. It
1149 has the cost of more pagetable lookup overhead, and also
1150 consumes more pagetable space per process.
1152 config ARCH_PHYS_ADDR_T_64BIT
1153 def_bool X86_64 || X86_PAE
1155 config ARCH_DMA_ADDR_T_64BIT
1156 def_bool X86_64 || HIGHMEM64G
1158 config DIRECT_GBPAGES
1159 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1163 Allow the kernel linear mapping to use 1GB pages on CPUs that
1164 support it. This can improve the kernel's performance a tiny bit by
1165 reducing TLB pressure. If in doubt, say "Y".
1167 # Common NUMA Features
1169 bool "Numa Memory Allocation and Scheduler Support"
1171 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1172 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1174 Enable NUMA (Non Uniform Memory Access) support.
1176 The kernel will try to allocate memory used by a CPU on the
1177 local memory controller of the CPU and add some more
1178 NUMA awareness to the kernel.
1180 For 64-bit this is recommended if the system is Intel Core i7
1181 (or later), AMD Opteron, or EM64T NUMA.
1183 For 32-bit this is only needed on (rare) 32-bit-only platforms
1184 that support NUMA topologies, such as NUMAQ / Summit, or if you
1185 boot a 32-bit kernel on a 64-bit NUMA platform.
1187 Otherwise, you should say N.
1189 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1190 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1194 prompt "Old style AMD Opteron NUMA detection"
1195 depends on X86_64 && NUMA && PCI
1197 Enable AMD NUMA node topology detection. You should say Y here if
1198 you have a multi processor AMD system. This uses an old method to
1199 read the NUMA configuration directly from the builtin Northbridge
1200 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1201 which also takes priority if both are compiled in.
1203 config X86_64_ACPI_NUMA
1205 prompt "ACPI NUMA detection"
1206 depends on X86_64 && NUMA && ACPI && PCI
1209 Enable ACPI SRAT based node topology detection.
1211 # Some NUMA nodes have memory ranges that span
1212 # other nodes. Even though a pfn is valid and
1213 # between a node's start and end pfns, it may not
1214 # reside on that node. See memmap_init_zone()
1216 config NODES_SPAN_OTHER_NODES
1218 depends on X86_64_ACPI_NUMA
1221 bool "NUMA emulation"
1224 Enable NUMA emulation. A flat machine will be split
1225 into virtual nodes when booted with "numa=fake=N", where N is the
1226 number of nodes. This is only useful for debugging.
1229 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1231 default "10" if MAXSMP
1232 default "6" if X86_64
1233 default "4" if X86_NUMAQ
1235 depends on NEED_MULTIPLE_NODES
1237 Specify the maximum number of NUMA Nodes available on the target
1238 system. Increases memory reserved to accommodate various tables.
1240 config HAVE_ARCH_BOOTMEM
1242 depends on X86_32 && NUMA
1244 config HAVE_ARCH_ALLOC_REMAP
1246 depends on X86_32 && NUMA
1248 config ARCH_HAVE_MEMORY_PRESENT
1250 depends on X86_32 && DISCONTIGMEM
1252 config NEED_NODE_MEMMAP_SIZE
1254 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1256 config ARCH_FLATMEM_ENABLE
1258 depends on X86_32 && !NUMA
1260 config ARCH_DISCONTIGMEM_ENABLE
1262 depends on NUMA && X86_32
1264 config ARCH_DISCONTIGMEM_DEFAULT
1266 depends on NUMA && X86_32
1268 config ARCH_SPARSEMEM_ENABLE
1270 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1271 select SPARSEMEM_STATIC if X86_32
1272 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1274 config ARCH_SPARSEMEM_DEFAULT
1278 config ARCH_SELECT_MEMORY_MODEL
1280 depends on ARCH_SPARSEMEM_ENABLE
1282 config ARCH_MEMORY_PROBE
1284 depends on MEMORY_HOTPLUG
1286 config ARCH_PROC_KCORE_TEXT
1288 depends on X86_64 && PROC_KCORE
1290 config ILLEGAL_POINTER_VALUE
1293 default 0xdead000000000000 if X86_64
1298 bool "Allocate 3rd-level pagetables from highmem"
1301 The VM uses one page table entry for each page of physical memory.
1302 For systems with a lot of RAM, this can be wasteful of precious
1303 low memory. Setting this option will put user-space page table
1304 entries in high memory.
1306 config X86_CHECK_BIOS_CORRUPTION
1307 bool "Check for low memory corruption"
1309 Periodically check for memory corruption in low memory, which
1310 is suspected to be caused by BIOS. Even when enabled in the
1311 configuration, it is disabled at runtime. Enable it by
1312 setting "memory_corruption_check=1" on the kernel command
1313 line. By default it scans the low 64k of memory every 60
1314 seconds; see the memory_corruption_check_size and
1315 memory_corruption_check_period parameters in
1316 Documentation/kernel-parameters.txt to adjust this.
1318 When enabled with the default parameters, this option has
1319 almost no overhead, as it reserves a relatively small amount
1320 of memory and scans it infrequently. It both detects corruption
1321 and prevents it from affecting the running system.
1323 It is, however, intended as a diagnostic tool; if repeatable
1324 BIOS-originated corruption always affects the same memory,
1325 you can use memmap= to prevent the kernel from using that
1328 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1329 bool "Set the default setting of memory_corruption_check"
1330 depends on X86_CHECK_BIOS_CORRUPTION
1333 Set whether the default state of memory_corruption_check is
1336 config X86_RESERVE_LOW
1337 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1341 Specify the amount of low memory to reserve for the BIOS.
1343 The first page contains BIOS data structures that the kernel
1344 must not use, so that page must always be reserved.
1346 By default we reserve the first 64K of physical RAM, as a
1347 number of BIOSes are known to corrupt that memory range
1348 during events such as suspend/resume or monitor cable
1349 insertion, so it must not be used by the kernel.
1351 You can set this to 4 if you are absolutely sure that you
1352 trust the BIOS to get all its memory reservations and usages
1353 right. If you know your BIOS have problems beyond the
1354 default 64K area, you can set this to 640 to avoid using the
1355 entire low memory range.
1357 If you have doubts about the BIOS (e.g. suspend/resume does
1358 not work or there's kernel crashes after certain hardware
1359 hotplug events) then you might want to enable
1360 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1361 typical corruption patterns.
1363 Leave this to the default value of 64 if you are unsure.
1365 config MATH_EMULATION
1367 prompt "Math emulation" if X86_32
1369 Linux can emulate a math coprocessor (used for floating point
1370 operations) if you don't have one. 486DX and Pentium processors have
1371 a math coprocessor built in, 486SX and 386 do not, unless you added
1372 a 487DX or 387, respectively. (The messages during boot time can
1373 give you some hints here ["man dmesg"].) Everyone needs either a
1374 coprocessor or this emulation.
1376 If you don't have a math coprocessor, you need to say Y here; if you
1377 say Y here even though you have a coprocessor, the coprocessor will
1378 be used nevertheless. (This behavior can be changed with the kernel
1379 command line option "no387", which comes handy if your coprocessor
1380 is broken. Try "man bootparam" or see the documentation of your boot
1381 loader (lilo or loadlin) about how to pass options to the kernel at
1382 boot time.) This means that it is a good idea to say Y here if you
1383 intend to use this kernel on different machines.
1385 More information about the internals of the Linux math coprocessor
1386 emulation can be found in <file:arch/x86/math-emu/README>.
1388 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1389 kernel, it won't hurt.
1393 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1395 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1396 the Memory Type Range Registers (MTRRs) may be used to control
1397 processor access to memory ranges. This is most useful if you have
1398 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1399 allows bus write transfers to be combined into a larger transfer
1400 before bursting over the PCI/AGP bus. This can increase performance
1401 of image write operations 2.5 times or more. Saying Y here creates a
1402 /proc/mtrr file which may be used to manipulate your processor's
1403 MTRRs. Typically the X server should use this.
1405 This code has a reasonably generic interface so that similar
1406 control registers on other processors can be easily supported
1409 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1410 Registers (ARRs) which provide a similar functionality to MTRRs. For
1411 these, the ARRs are used to emulate the MTRRs.
1412 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1413 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1414 write-combining. All of these processors are supported by this code
1415 and it makes sense to say Y here if you have one of them.
1417 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1418 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1419 can lead to all sorts of problems, so it's good to say Y here.
1421 You can safely say Y even if your machine doesn't have MTRRs, you'll
1422 just add about 9 KB to your kernel.
1424 See <file:Documentation/x86/mtrr.txt> for more information.
1426 config MTRR_SANITIZER
1428 prompt "MTRR cleanup support"
1431 Convert MTRR layout from continuous to discrete, so X drivers can
1432 add writeback entries.
1434 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1435 The largest mtrr entry size for a continuous block can be set with
1440 config MTRR_SANITIZER_ENABLE_DEFAULT
1441 int "MTRR cleanup enable value (0-1)"
1444 depends on MTRR_SANITIZER
1446 Enable mtrr cleanup default value
1448 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1449 int "MTRR cleanup spare reg num (0-7)"
1452 depends on MTRR_SANITIZER
1454 mtrr cleanup spare entries default, it can be changed via
1455 mtrr_spare_reg_nr=N on the kernel command line.
1459 prompt "x86 PAT support" if EXPERT
1462 Use PAT attributes to setup page level cache control.
1464 PATs are the modern equivalents of MTRRs and are much more
1465 flexible than MTRRs.
1467 Say N here if you see bootup problems (boot crash, boot hang,
1468 spontaneous reboots) or a non-working video driver.
1472 config ARCH_USES_PG_UNCACHED
1478 prompt "x86 architectural random number generator" if EXPERT
1480 Enable the x86 architectural RDRAND instruction
1481 (Intel Bull Mountain technology) to generate random numbers.
1482 If supported, this is a high bandwidth, cryptographically
1483 secure hardware random number generator.
1486 bool "EFI runtime service support"
1489 This enables the kernel to use EFI runtime services that are
1490 available (such as the EFI variable services).
1492 This option is only useful on systems that have EFI firmware.
1493 In addition, you should use the latest ELILO loader available
1494 at <http://elilo.sourceforge.net> in order to take advantage
1495 of EFI runtime services. However, even with this option, the
1496 resultant kernel should continue to boot on existing non-EFI
1500 bool "EFI stub support"
1503 This kernel feature allows a bzImage to be loaded directly
1504 by EFI firmware without the use of a bootloader.
1508 prompt "Enable seccomp to safely compute untrusted bytecode"
1510 This kernel feature is useful for number crunching applications
1511 that may need to compute untrusted bytecode during their
1512 execution. By using pipes or other transports made available to
1513 the process as file descriptors supporting the read/write
1514 syscalls, it's possible to isolate those applications in
1515 their own address space using seccomp. Once seccomp is
1516 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1517 and the task is only allowed to execute a few safe syscalls
1518 defined by each seccomp mode.
1520 If unsure, say Y. Only embedded should say N here.
1522 config CC_STACKPROTECTOR
1523 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1525 This option turns on the -fstack-protector GCC feature. This
1526 feature puts, at the beginning of functions, a canary value on
1527 the stack just before the return address, and validates
1528 the value just before actually returning. Stack based buffer
1529 overflows (that need to overwrite this return address) now also
1530 overwrite the canary, which gets detected and the attack is then
1531 neutralized via a kernel panic.
1533 This feature requires gcc version 4.2 or above, or a distribution
1534 gcc with the feature backported. Older versions are automatically
1535 detected and for those versions, this configuration option is
1536 ignored. (and a warning is printed during bootup)
1538 source kernel/Kconfig.hz
1541 bool "kexec system call"
1543 kexec is a system call that implements the ability to shutdown your
1544 current kernel, and to start another kernel. It is like a reboot
1545 but it is independent of the system firmware. And like a reboot
1546 you can start any kernel with it, not just Linux.
1548 The name comes from the similarity to the exec system call.
1550 It is an ongoing process to be certain the hardware in a machine
1551 is properly shutdown, so do not be surprised if this code does not
1552 initially work for you. It may help to enable device hotplugging
1553 support. As of this writing the exact hardware interface is
1554 strongly in flux, so no good recommendation can be made.
1557 bool "kernel crash dumps"
1558 depends on X86_64 || (X86_32 && HIGHMEM)
1560 Generate crash dump after being started by kexec.
1561 This should be normally only set in special crash dump kernels
1562 which are loaded in the main kernel with kexec-tools into
1563 a specially reserved region and then later executed after
1564 a crash by kdump/kexec. The crash dump kernel must be compiled
1565 to a memory address not used by the main kernel or BIOS using
1566 PHYSICAL_START, or it must be built as a relocatable image
1567 (CONFIG_RELOCATABLE=y).
1568 For more details see Documentation/kdump/kdump.txt
1571 bool "kexec jump (EXPERIMENTAL)"
1572 depends on EXPERIMENTAL
1573 depends on KEXEC && HIBERNATION
1575 Jump between original kernel and kexeced kernel and invoke
1576 code in physical address mode via KEXEC
1578 config PHYSICAL_START
1579 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1582 This gives the physical address where the kernel is loaded.
1584 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1585 bzImage will decompress itself to above physical address and
1586 run from there. Otherwise, bzImage will run from the address where
1587 it has been loaded by the boot loader and will ignore above physical
1590 In normal kdump cases one does not have to set/change this option
1591 as now bzImage can be compiled as a completely relocatable image
1592 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1593 address. This option is mainly useful for the folks who don't want
1594 to use a bzImage for capturing the crash dump and want to use a
1595 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1596 to be specifically compiled to run from a specific memory area
1597 (normally a reserved region) and this option comes handy.
1599 So if you are using bzImage for capturing the crash dump,
1600 leave the value here unchanged to 0x1000000 and set
1601 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1602 for capturing the crash dump change this value to start of
1603 the reserved region. In other words, it can be set based on
1604 the "X" value as specified in the "crashkernel=YM@XM"
1605 command line boot parameter passed to the panic-ed
1606 kernel. Please take a look at Documentation/kdump/kdump.txt
1607 for more details about crash dumps.
1609 Usage of bzImage for capturing the crash dump is recommended as
1610 one does not have to build two kernels. Same kernel can be used
1611 as production kernel and capture kernel. Above option should have
1612 gone away after relocatable bzImage support is introduced. But it
1613 is present because there are users out there who continue to use
1614 vmlinux for dump capture. This option should go away down the
1617 Don't change this unless you know what you are doing.
1620 bool "Build a relocatable kernel"
1623 This builds a kernel image that retains relocation information
1624 so it can be loaded someplace besides the default 1MB.
1625 The relocations tend to make the kernel binary about 10% larger,
1626 but are discarded at runtime.
1628 One use is for the kexec on panic case where the recovery kernel
1629 must live at a different physical address than the primary
1632 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1633 it has been loaded at and the compile time physical address
1634 (CONFIG_PHYSICAL_START) is ignored.
1636 # Relocation on x86-32 needs some additional build support
1637 config X86_NEED_RELOCS
1639 depends on X86_32 && RELOCATABLE
1641 config PHYSICAL_ALIGN
1642 hex "Alignment value to which kernel should be aligned" if X86_32
1644 range 0x2000 0x1000000
1646 This value puts the alignment restrictions on physical address
1647 where kernel is loaded and run from. Kernel is compiled for an
1648 address which meets above alignment restriction.
1650 If bootloader loads the kernel at a non-aligned address and
1651 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1652 address aligned to above value and run from there.
1654 If bootloader loads the kernel at a non-aligned address and
1655 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1656 load address and decompress itself to the address it has been
1657 compiled for and run from there. The address for which kernel is
1658 compiled already meets above alignment restrictions. Hence the
1659 end result is that kernel runs from a physical address meeting
1660 above alignment restrictions.
1662 Don't change this unless you know what you are doing.
1665 bool "Support for hot-pluggable CPUs"
1666 depends on SMP && HOTPLUG
1668 Say Y here to allow turning CPUs off and on. CPUs can be
1669 controlled through /sys/devices/system/cpu.
1670 ( Note: power management support will enable this option
1671 automatically on SMP systems. )
1672 Say N if you want to disable CPU hotplug.
1676 prompt "Compat VDSO support"
1677 depends on X86_32 || IA32_EMULATION
1679 Map the 32-bit VDSO to the predictable old-style address too.
1681 Say N here if you are running a sufficiently recent glibc
1682 version (2.3.3 or later), to remove the high-mapped
1683 VDSO mapping and to exclusively use the randomized VDSO.
1688 bool "Built-in kernel command line"
1690 Allow for specifying boot arguments to the kernel at
1691 build time. On some systems (e.g. embedded ones), it is
1692 necessary or convenient to provide some or all of the
1693 kernel boot arguments with the kernel itself (that is,
1694 to not rely on the boot loader to provide them.)
1696 To compile command line arguments into the kernel,
1697 set this option to 'Y', then fill in the
1698 the boot arguments in CONFIG_CMDLINE.
1700 Systems with fully functional boot loaders (i.e. non-embedded)
1701 should leave this option set to 'N'.
1704 string "Built-in kernel command string"
1705 depends on CMDLINE_BOOL
1708 Enter arguments here that should be compiled into the kernel
1709 image and used at boot time. If the boot loader provides a
1710 command line at boot time, it is appended to this string to
1711 form the full kernel command line, when the system boots.
1713 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1714 change this behavior.
1716 In most cases, the command line (whether built-in or provided
1717 by the boot loader) should specify the device for the root
1720 config CMDLINE_OVERRIDE
1721 bool "Built-in command line overrides boot loader arguments"
1722 depends on CMDLINE_BOOL
1724 Set this option to 'Y' to have the kernel ignore the boot loader
1725 command line, and use ONLY the built-in command line.
1727 This is used to work around broken boot loaders. This should
1728 be set to 'N' under normal conditions.
1732 config ARCH_ENABLE_MEMORY_HOTPLUG
1734 depends on X86_64 || (X86_32 && HIGHMEM)
1736 config ARCH_ENABLE_MEMORY_HOTREMOVE
1738 depends on MEMORY_HOTPLUG
1740 config USE_PERCPU_NUMA_NODE_ID
1744 menu "Power management and ACPI options"
1746 config ARCH_HIBERNATION_HEADER
1748 depends on X86_64 && HIBERNATION
1750 source "kernel/power/Kconfig"
1752 source "drivers/acpi/Kconfig"
1754 source "drivers/sfi/Kconfig"
1761 tristate "APM (Advanced Power Management) BIOS support"
1762 depends on X86_32 && PM_SLEEP
1764 APM is a BIOS specification for saving power using several different
1765 techniques. This is mostly useful for battery powered laptops with
1766 APM compliant BIOSes. If you say Y here, the system time will be
1767 reset after a RESUME operation, the /proc/apm device will provide
1768 battery status information, and user-space programs will receive
1769 notification of APM "events" (e.g. battery status change).
1771 If you select "Y" here, you can disable actual use of the APM
1772 BIOS by passing the "apm=off" option to the kernel at boot time.
1774 Note that the APM support is almost completely disabled for
1775 machines with more than one CPU.
1777 In order to use APM, you will need supporting software. For location
1778 and more information, read <file:Documentation/power/apm-acpi.txt>
1779 and the Battery Powered Linux mini-HOWTO, available from
1780 <http://www.tldp.org/docs.html#howto>.
1782 This driver does not spin down disk drives (see the hdparm(8)
1783 manpage ("man 8 hdparm") for that), and it doesn't turn off
1784 VESA-compliant "green" monitors.
1786 This driver does not support the TI 4000M TravelMate and the ACER
1787 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1788 desktop machines also don't have compliant BIOSes, and this driver
1789 may cause those machines to panic during the boot phase.
1791 Generally, if you don't have a battery in your machine, there isn't
1792 much point in using this driver and you should say N. If you get
1793 random kernel OOPSes or reboots that don't seem to be related to
1794 anything, try disabling/enabling this option (or disabling/enabling
1797 Some other things you should try when experiencing seemingly random,
1800 1) make sure that you have enough swap space and that it is
1802 2) pass the "no-hlt" option to the kernel
1803 3) switch on floating point emulation in the kernel and pass
1804 the "no387" option to the kernel
1805 4) pass the "floppy=nodma" option to the kernel
1806 5) pass the "mem=4M" option to the kernel (thereby disabling
1807 all but the first 4 MB of RAM)
1808 6) make sure that the CPU is not over clocked.
1809 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1810 8) disable the cache from your BIOS settings
1811 9) install a fan for the video card or exchange video RAM
1812 10) install a better fan for the CPU
1813 11) exchange RAM chips
1814 12) exchange the motherboard.
1816 To compile this driver as a module, choose M here: the
1817 module will be called apm.
1821 config APM_IGNORE_USER_SUSPEND
1822 bool "Ignore USER SUSPEND"
1824 This option will ignore USER SUSPEND requests. On machines with a
1825 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1826 series notebooks, it is necessary to say Y because of a BIOS bug.
1828 config APM_DO_ENABLE
1829 bool "Enable PM at boot time"
1831 Enable APM features at boot time. From page 36 of the APM BIOS
1832 specification: "When disabled, the APM BIOS does not automatically
1833 power manage devices, enter the Standby State, enter the Suspend
1834 State, or take power saving steps in response to CPU Idle calls."
1835 This driver will make CPU Idle calls when Linux is idle (unless this
1836 feature is turned off -- see "Do CPU IDLE calls", below). This
1837 should always save battery power, but more complicated APM features
1838 will be dependent on your BIOS implementation. You may need to turn
1839 this option off if your computer hangs at boot time when using APM
1840 support, or if it beeps continuously instead of suspending. Turn
1841 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1842 T400CDT. This is off by default since most machines do fine without
1846 bool "Make CPU Idle calls when idle"
1848 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1849 On some machines, this can activate improved power savings, such as
1850 a slowed CPU clock rate, when the machine is idle. These idle calls
1851 are made after the idle loop has run for some length of time (e.g.,
1852 333 mS). On some machines, this will cause a hang at boot time or
1853 whenever the CPU becomes idle. (On machines with more than one CPU,
1854 this option does nothing.)
1856 config APM_DISPLAY_BLANK
1857 bool "Enable console blanking using APM"
1859 Enable console blanking using the APM. Some laptops can use this to
1860 turn off the LCD backlight when the screen blanker of the Linux
1861 virtual console blanks the screen. Note that this is only used by
1862 the virtual console screen blanker, and won't turn off the backlight
1863 when using the X Window system. This also doesn't have anything to
1864 do with your VESA-compliant power-saving monitor. Further, this
1865 option doesn't work for all laptops -- it might not turn off your
1866 backlight at all, or it might print a lot of errors to the console,
1867 especially if you are using gpm.
1869 config APM_ALLOW_INTS
1870 bool "Allow interrupts during APM BIOS calls"
1872 Normally we disable external interrupts while we are making calls to
1873 the APM BIOS as a measure to lessen the effects of a badly behaving
1874 BIOS implementation. The BIOS should reenable interrupts if it
1875 needs to. Unfortunately, some BIOSes do not -- especially those in
1876 many of the newer IBM Thinkpads. If you experience hangs when you
1877 suspend, try setting this to Y. Otherwise, say N.
1881 source "drivers/cpufreq/Kconfig"
1883 source "drivers/cpuidle/Kconfig"
1885 source "drivers/idle/Kconfig"
1890 menu "Bus options (PCI etc.)"
1895 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1897 Find out whether you have a PCI motherboard. PCI is the name of a
1898 bus system, i.e. the way the CPU talks to the other stuff inside
1899 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1900 VESA. If you have PCI, say Y, otherwise N.
1903 prompt "PCI access mode"
1904 depends on X86_32 && PCI
1907 On PCI systems, the BIOS can be used to detect the PCI devices and
1908 determine their configuration. However, some old PCI motherboards
1909 have BIOS bugs and may crash if this is done. Also, some embedded
1910 PCI-based systems don't have any BIOS at all. Linux can also try to
1911 detect the PCI hardware directly without using the BIOS.
1913 With this option, you can specify how Linux should detect the
1914 PCI devices. If you choose "BIOS", the BIOS will be used,
1915 if you choose "Direct", the BIOS won't be used, and if you
1916 choose "MMConfig", then PCI Express MMCONFIG will be used.
1917 If you choose "Any", the kernel will try MMCONFIG, then the
1918 direct access method and falls back to the BIOS if that doesn't
1919 work. If unsure, go with the default, which is "Any".
1924 config PCI_GOMMCONFIG
1941 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1943 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1946 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1950 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1954 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1958 depends on PCI && XEN
1966 bool "Support mmconfig PCI config space access"
1967 depends on X86_64 && PCI && ACPI
1969 config PCI_CNB20LE_QUIRK
1970 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1972 depends on PCI && EXPERIMENTAL
1974 Read the PCI windows out of the CNB20LE host bridge. This allows
1975 PCI hotplug to work on systems with the CNB20LE chipset which do
1978 There's no public spec for this chipset, and this functionality
1979 is known to be incomplete.
1981 You should say N unless you know you need this.
1983 source "drivers/pci/pcie/Kconfig"
1985 source "drivers/pci/Kconfig"
1987 # x86_64 have no ISA slots, but can have ISA-style DMA.
1989 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1992 Enables ISA-style DMA support for devices requiring such controllers.
2000 Find out whether you have ISA slots on your motherboard. ISA is the
2001 name of a bus system, i.e. the way the CPU talks to the other stuff
2002 inside your box. Other bus systems are PCI, EISA, MicroChannel
2003 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2004 newer boards don't support it. If you have ISA, say Y, otherwise N.
2010 The Extended Industry Standard Architecture (EISA) bus was
2011 developed as an open alternative to the IBM MicroChannel bus.
2013 The EISA bus provided some of the features of the IBM MicroChannel
2014 bus while maintaining backward compatibility with cards made for
2015 the older ISA bus. The EISA bus saw limited use between 1988 and
2016 1995 when it was made obsolete by the PCI bus.
2018 Say Y here if you are building a kernel for an EISA-based machine.
2022 source "drivers/eisa/Kconfig"
2027 MicroChannel Architecture is found in some IBM PS/2 machines and
2028 laptops. It is a bus system similar to PCI or ISA. See
2029 <file:Documentation/mca.txt> (and especially the web page given
2030 there) before attempting to build an MCA bus kernel.
2032 source "drivers/mca/Kconfig"
2035 tristate "NatSemi SCx200 support"
2037 This provides basic support for National Semiconductor's
2038 (now AMD's) Geode processors. The driver probes for the
2039 PCI-IDs of several on-chip devices, so its a good dependency
2040 for other scx200_* drivers.
2042 If compiled as a module, the driver is named scx200.
2044 config SCx200HR_TIMER
2045 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2049 This driver provides a clocksource built upon the on-chip
2050 27MHz high-resolution timer. Its also a workaround for
2051 NSC Geode SC-1100's buggy TSC, which loses time when the
2052 processor goes idle (as is done by the scheduler). The
2053 other workaround is idle=poll boot option.
2056 bool "One Laptop Per Child support"
2063 Add support for detecting the unique features of the OLPC
2067 bool "OLPC XO-1 Power Management"
2068 depends on OLPC && MFD_CS5535 && PM_SLEEP
2071 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2074 bool "OLPC XO-1 Real Time Clock"
2075 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2077 Add support for the XO-1 real time clock, which can be used as a
2078 programmable wakeup source.
2081 bool "OLPC XO-1 SCI extras"
2082 depends on OLPC && OLPC_XO1_PM
2087 Add support for SCI-based features of the OLPC XO-1 laptop:
2088 - EC-driven system wakeups
2092 - AC adapter status updates
2093 - Battery status updates
2095 config OLPC_XO15_SCI
2096 bool "OLPC XO-1.5 SCI extras"
2097 depends on OLPC && ACPI
2100 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2101 - EC-driven system wakeups
2102 - AC adapter status updates
2103 - Battery status updates
2106 bool "PCEngines ALIX System Support (LED setup)"
2109 This option enables system support for the PCEngines ALIX.
2110 At present this just sets up LEDs for GPIO control on
2111 ALIX2/3/6 boards. However, other system specific setup should
2114 Note: You must still enable the drivers for GPIO and LED support
2115 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2117 Note: You have to set alix.force=1 for boards with Award BIOS.
2120 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2123 This option enables system support for the Soekris Engineering net5501.
2126 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2130 This option enables system support for the Traverse Technologies GEOS.
2136 depends on CPU_SUP_AMD && PCI
2138 source "drivers/pcmcia/Kconfig"
2140 source "drivers/pci/hotplug/Kconfig"
2143 bool "RapidIO support"
2147 If you say Y here, the kernel will include drivers and
2148 infrastructure code to support RapidIO interconnect devices.
2150 source "drivers/rapidio/Kconfig"
2155 menu "Executable file formats / Emulations"
2157 source "fs/Kconfig.binfmt"
2159 config IA32_EMULATION
2160 bool "IA32 Emulation"
2162 select COMPAT_BINFMT_ELF
2164 Include code to run legacy 32-bit programs under a
2165 64-bit kernel. You should likely turn this on, unless you're
2166 100% sure that you don't have any 32-bit programs left.
2169 tristate "IA32 a.out support"
2170 depends on IA32_EMULATION
2172 Support old a.out binaries in the 32bit emulation.
2175 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2176 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2178 Include code to run binaries for the x32 native 32-bit ABI
2179 for 64-bit processors. An x32 process gets access to the
2180 full 64-bit register file and wide data path while leaving
2181 pointers at 32 bits for smaller memory footprint.
2183 You will need a recent binutils (2.22 or later) with
2184 elf32_x86_64 support enabled to compile a kernel with this
2189 depends on IA32_EMULATION || X86_X32
2190 select ARCH_WANT_OLD_COMPAT_IPC
2192 config COMPAT_FOR_U64_ALIGNMENT
2196 config SYSVIPC_COMPAT
2198 depends on COMPAT && SYSVIPC
2202 depends on COMPAT && KEYS
2208 config HAVE_ATOMIC_IOMAP
2212 config HAVE_TEXT_POKE_SMP
2214 select STOP_MACHINE if SMP
2216 source "net/Kconfig"
2218 source "drivers/Kconfig"
2220 source "drivers/firmware/Kconfig"
2224 source "arch/x86/Kconfig.debug"
2226 source "security/Kconfig"
2228 source "crypto/Kconfig"
2230 source "arch/x86/kvm/Kconfig"
2232 source "lib/Kconfig"