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
86 select BUILDTIME_EXTABLE_SORT
88 config INSTRUCTION_DECODER
89 def_bool (KPROBES || PERF_EVENTS)
93 default "elf32-i386" if X86_32
94 default "elf64-x86-64" if X86_64
98 default "arch/x86/configs/i386_defconfig" if X86_32
99 default "arch/x86/configs/x86_64_defconfig" if X86_64
101 config GENERIC_CMOS_UPDATE
104 config CLOCKSOURCE_WATCHDOG
107 config GENERIC_CLOCKEVENTS
110 config ARCH_CLOCKSOURCE_DATA
114 config GENERIC_CLOCKEVENTS_BROADCAST
116 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
118 config LOCKDEP_SUPPORT
121 config STACKTRACE_SUPPORT
124 config HAVE_LATENCYTOP_SUPPORT
133 config NEED_DMA_MAP_STATE
134 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
136 config NEED_SG_DMA_LENGTH
139 config GENERIC_ISA_DMA
145 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
147 config GENERIC_BUG_RELATIVE_POINTERS
150 config GENERIC_HWEIGHT
156 config ARCH_MAY_HAVE_PC_FDC
159 config RWSEM_GENERIC_SPINLOCK
162 config RWSEM_XCHGADD_ALGORITHM
165 config GENERIC_CALIBRATE_DELAY
168 config GENERIC_TIME_VSYSCALL
172 config ARCH_HAS_CPU_RELAX
175 config ARCH_HAS_DEFAULT_IDLE
178 config ARCH_HAS_CACHE_LINE_SIZE
181 config ARCH_HAS_CPU_AUTOPROBE
184 config HAVE_SETUP_PER_CPU_AREA
187 config NEED_PER_CPU_EMBED_FIRST_CHUNK
190 config NEED_PER_CPU_PAGE_FIRST_CHUNK
193 config ARCH_HIBERNATION_POSSIBLE
196 config ARCH_SUSPEND_POSSIBLE
207 config ARCH_SUPPORTS_OPTIMIZED_INLINING
210 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
213 config HAVE_INTEL_TXT
215 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
219 depends on X86_32 && SMP
223 depends on X86_64 && SMP
229 config X86_32_LAZY_GS
231 depends on X86_32 && !CC_STACKPROTECTOR
233 config ARCH_HWEIGHT_CFLAGS
235 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
236 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
241 config ARCH_CPU_PROBE_RELEASE
243 depends on HOTPLUG_CPU
245 source "init/Kconfig"
246 source "kernel/Kconfig.freezer"
248 menu "Processor type and features"
251 bool "DMA memory allocation support" if EXPERT
254 DMA memory allocation support allows devices with less than 32-bit
255 addressing to allocate within the first 16MB of address space.
256 Disable if no such devices will be used.
260 source "kernel/time/Kconfig"
263 bool "Symmetric multi-processing support"
265 This enables support for systems with more than one CPU. If you have
266 a system with only one CPU, like most personal computers, say N. If
267 you have a system with more than one CPU, say Y.
269 If you say N here, the kernel will run on single and multiprocessor
270 machines, but will use only one CPU of a multiprocessor machine. If
271 you say Y here, the kernel will run on many, but not all,
272 singleprocessor machines. On a singleprocessor machine, the kernel
273 will run faster if you say N here.
275 Note that if you say Y here and choose architecture "586" or
276 "Pentium" under "Processor family", the kernel will not work on 486
277 architectures. Similarly, multiprocessor kernels for the "PPro"
278 architecture may not work on all Pentium based boards.
280 People using multiprocessor machines who say Y here should also say
281 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
282 Management" code will be disabled if you say Y here.
284 See also <file:Documentation/x86/i386/IO-APIC.txt>,
285 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
286 <http://www.tldp.org/docs.html#howto>.
288 If you don't know what to do here, say N.
291 bool "Support x2apic"
292 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
294 This enables x2apic support on CPUs that have this feature.
296 This allows 32-bit apic IDs (so it can support very large systems),
297 and accesses the local apic via MSRs not via mmio.
299 If you don't know what to do here, say N.
302 bool "Enable MPS table" if ACPI
304 depends on X86_LOCAL_APIC
306 For old smp systems that do not have proper acpi support. Newer systems
307 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
310 bool "Support for big SMP systems with more than 8 CPUs"
311 depends on X86_32 && SMP
313 This option is needed for the systems that have more than 8 CPUs
316 config X86_EXTENDED_PLATFORM
317 bool "Support for extended (non-PC) x86 platforms"
320 If you disable this option then the kernel will only support
321 standard PC platforms. (which covers the vast majority of
324 If you enable this option then you'll be able to select support
325 for the following (non-PC) 32 bit x86 platforms:
329 SGI 320/540 (Visual Workstation)
330 Summit/EXA (IBM x440)
331 Unisys ES7000 IA32 series
332 Moorestown MID devices
334 If you have one of these systems, or if you want to build a
335 generic distribution kernel, say Y here - otherwise say N.
339 config X86_EXTENDED_PLATFORM
340 bool "Support for extended (non-PC) x86 platforms"
343 If you disable this option then the kernel will only support
344 standard PC platforms. (which covers the vast majority of
347 If you enable this option then you'll be able to select support
348 for the following (non-PC) 64 bit x86 platforms:
353 If you have one of these systems, or if you want to build a
354 generic distribution kernel, say Y here - otherwise say N.
356 # This is an alphabetically sorted list of 64 bit extended platforms
357 # Please maintain the alphabetic order if and when there are additions
359 bool "Numascale NumaChip"
361 depends on X86_EXTENDED_PLATFORM
364 depends on X86_X2APIC
366 Adds support for Numascale NumaChip large-SMP systems. Needed to
367 enable more than ~168 cores.
368 If you don't have one of these, you should say N here.
372 select PARAVIRT_GUEST
374 depends on X86_64 && PCI
375 depends on X86_EXTENDED_PLATFORM
377 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
378 supposed to run on these EM64T-based machines. Only choose this option
379 if you have one of these machines.
382 bool "SGI Ultraviolet"
384 depends on X86_EXTENDED_PLATFORM
386 depends on X86_X2APIC
388 This option is needed in order to support SGI Ultraviolet systems.
389 If you don't have one of these, you should say N here.
391 # Following is an alphabetically sorted list of 32 bit extended platforms
392 # Please maintain the alphabetic order if and when there are additions
395 bool "CE4100 TV platform"
397 depends on PCI_GODIRECT
399 depends on X86_EXTENDED_PLATFORM
400 select X86_REBOOTFIXUPS
402 select OF_EARLY_FLATTREE
405 Select for the Intel CE media processor (CE4100) SOC.
406 This option compiles in support for the CE4100 SOC for settop
407 boxes and media devices.
409 config X86_WANT_INTEL_MID
410 bool "Intel MID platform support"
412 depends on X86_EXTENDED_PLATFORM
414 Select to build a kernel capable of supporting Intel MID platform
415 systems which do not have the PCI legacy interfaces (Moorestown,
416 Medfield). If you are building for a PC class system say N here.
418 if X86_WANT_INTEL_MID
424 bool "Medfield MID platform"
427 depends on X86_IO_APIC
435 select X86_PLATFORM_DEVICES
436 select MFD_INTEL_MSIC
438 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
439 Internet Device(MID) platform.
440 Unlike standard x86 PCs, Medfield does not have many legacy devices
441 nor standard legacy replacement devices/features. e.g. Medfield does
442 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
447 bool "RDC R-321x SoC"
449 depends on X86_EXTENDED_PLATFORM
451 select X86_REBOOTFIXUPS
453 This option is needed for RDC R-321x system-on-chip, also known
455 If you don't have one of these chips, you should say N here.
457 config X86_32_NON_STANDARD
458 bool "Support non-standard 32-bit SMP architectures"
459 depends on X86_32 && SMP
460 depends on X86_EXTENDED_PLATFORM
462 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
463 subarchitectures. It is intended for a generic binary kernel.
464 if you select them all, kernel will probe it one by one. and will
467 # Alphabetically sorted list of Non standard 32 bit platforms
470 bool "NUMAQ (IBM/Sequent)"
471 depends on X86_32_NON_STANDARD
476 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
477 NUMA multiquad box. This changes the way that processors are
478 bootstrapped, and uses Clustered Logical APIC addressing mode instead
479 of Flat Logical. You will need a new lynxer.elf file to flash your
480 firmware with - send email to <Martin.Bligh@us.ibm.com>.
482 config X86_SUPPORTS_MEMORY_FAILURE
484 # MCE code calls memory_failure():
486 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
487 depends on !X86_NUMAQ
488 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
489 depends on X86_64 || !SPARSEMEM
490 select ARCH_SUPPORTS_MEMORY_FAILURE
493 bool "SGI 320/540 (Visual Workstation)"
494 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
495 depends on X86_32_NON_STANDARD
497 The SGI Visual Workstation series is an IA32-based workstation
498 based on SGI systems chips with some legacy PC hardware attached.
500 Say Y here to create a kernel to run on the SGI 320 or 540.
502 A kernel compiled for the Visual Workstation will run on general
503 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
506 bool "Summit/EXA (IBM x440)"
507 depends on X86_32_NON_STANDARD
509 This option is needed for IBM systems that use the Summit/EXA chipset.
510 In particular, it is needed for the x440.
513 bool "Unisys ES7000 IA32 series"
514 depends on X86_32_NON_STANDARD && X86_BIGSMP
516 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
517 supposed to run on an IA32-based Unisys ES7000 system.
520 tristate "Eurobraille/Iris poweroff module"
523 The Iris machines from EuroBraille do not have APM or ACPI support
524 to shut themselves down properly. A special I/O sequence is
525 needed to do so, which is what this module does at
528 This is only for Iris machines from EuroBraille.
532 config SCHED_OMIT_FRAME_POINTER
534 prompt "Single-depth WCHAN output"
537 Calculate simpler /proc/<PID>/wchan values. If this option
538 is disabled then wchan values will recurse back to the
539 caller function. This provides more accurate wchan values,
540 at the expense of slightly more scheduling overhead.
542 If in doubt, say "Y".
544 menuconfig PARAVIRT_GUEST
545 bool "Paravirtualized guest support"
547 Say Y here to get to see options related to running Linux under
548 various hypervisors. This option alone does not add any kernel code.
550 If you say N, all options in this submenu will be skipped and disabled.
554 config PARAVIRT_TIME_ACCOUNTING
555 bool "Paravirtual steal time accounting"
559 Select this option to enable fine granularity task steal time
560 accounting. Time spent executing other tasks in parallel with
561 the current vCPU is discounted from the vCPU power. To account for
562 that, there can be a small performance impact.
564 If in doubt, say N here.
566 source "arch/x86/xen/Kconfig"
569 bool "KVM paravirtualized clock"
571 select PARAVIRT_CLOCK
573 Turning on this option will allow you to run a paravirtualized clock
574 when running over the KVM hypervisor. Instead of relying on a PIT
575 (or probably other) emulation by the underlying device model, the host
576 provides the guest with timing infrastructure such as time of day, and
580 bool "KVM Guest support"
583 This option enables various optimizations for running under the KVM
586 source "arch/x86/lguest/Kconfig"
589 bool "Enable paravirtualization code"
591 This changes the kernel so it can modify itself when it is run
592 under a hypervisor, potentially improving performance significantly
593 over full virtualization. However, when run without a hypervisor
594 the kernel is theoretically slower and slightly larger.
596 config PARAVIRT_SPINLOCKS
597 bool "Paravirtualization layer for spinlocks"
598 depends on PARAVIRT && SMP && EXPERIMENTAL
600 Paravirtualized spinlocks allow a pvops backend to replace the
601 spinlock implementation with something virtualization-friendly
602 (for example, block the virtual CPU rather than spinning).
604 Unfortunately the downside is an up to 5% performance hit on
605 native kernels, with various workloads.
607 If you are unsure how to answer this question, answer N.
609 config PARAVIRT_CLOCK
614 config PARAVIRT_DEBUG
615 bool "paravirt-ops debugging"
616 depends on PARAVIRT && DEBUG_KERNEL
618 Enable to debug paravirt_ops internals. Specifically, BUG if
619 a paravirt_op is missing when it is called.
627 This option adds a kernel parameter 'memtest', which allows memtest
629 memtest=0, mean disabled; -- default
630 memtest=1, mean do 1 test pattern;
632 memtest=4, mean do 4 test patterns.
633 If you are unsure how to answer this question, answer N.
635 config X86_SUMMIT_NUMA
637 depends on X86_32 && NUMA && X86_32_NON_STANDARD
639 config X86_CYCLONE_TIMER
641 depends on X86_SUMMIT
643 source "arch/x86/Kconfig.cpu"
647 prompt "HPET Timer Support" if X86_32
649 Use the IA-PC HPET (High Precision Event Timer) to manage
650 time in preference to the PIT and RTC, if a HPET is
652 HPET is the next generation timer replacing legacy 8254s.
653 The HPET provides a stable time base on SMP
654 systems, unlike the TSC, but it is more expensive to access,
655 as it is off-chip. You can find the HPET spec at
656 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
658 You can safely choose Y here. However, HPET will only be
659 activated if the platform and the BIOS support this feature.
660 Otherwise the 8254 will be used for timing services.
662 Choose N to continue using the legacy 8254 timer.
664 config HPET_EMULATE_RTC
666 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
669 def_bool y if X86_INTEL_MID
670 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
672 depends on X86_INTEL_MID && SFI
674 APB timer is the replacement for 8254, HPET on X86 MID platforms.
675 The APBT provides a stable time base on SMP
676 systems, unlike the TSC, but it is more expensive to access,
677 as it is off-chip. APB timers are always running regardless of CPU
678 C states, they are used as per CPU clockevent device when possible.
680 # Mark as expert because too many people got it wrong.
681 # The code disables itself when not needed.
684 bool "Enable DMI scanning" if EXPERT
686 Enabled scanning of DMI to identify machine quirks. Say Y
687 here unless you have verified that your setup is not
688 affected by entries in the DMI blacklist. Required by PNP
692 bool "GART IOMMU support" if EXPERT
695 depends on X86_64 && PCI && AMD_NB
697 Support for full DMA access of devices with 32bit memory access only
698 on systems with more than 3GB. This is usually needed for USB,
699 sound, many IDE/SATA chipsets and some other devices.
700 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
701 based hardware IOMMU and a software bounce buffer based IOMMU used
702 on Intel systems and as fallback.
703 The code is only active when needed (enough memory and limited
704 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
708 bool "IBM Calgary IOMMU support"
710 depends on X86_64 && PCI && EXPERIMENTAL
712 Support for hardware IOMMUs in IBM's xSeries x366 and x460
713 systems. Needed to run systems with more than 3GB of memory
714 properly with 32-bit PCI devices that do not support DAC
715 (Double Address Cycle). Calgary also supports bus level
716 isolation, where all DMAs pass through the IOMMU. This
717 prevents them from going anywhere except their intended
718 destination. This catches hard-to-find kernel bugs and
719 mis-behaving drivers and devices that do not use the DMA-API
720 properly to set up their DMA buffers. The IOMMU can be
721 turned off at boot time with the iommu=off parameter.
722 Normally the kernel will make the right choice by itself.
725 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
727 prompt "Should Calgary be enabled by default?"
728 depends on CALGARY_IOMMU
730 Should Calgary be enabled by default? if you choose 'y', Calgary
731 will be used (if it exists). If you choose 'n', Calgary will not be
732 used even if it exists. If you choose 'n' and would like to use
733 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
736 # need this always selected by IOMMU for the VIA workaround
740 Support for software bounce buffers used on x86-64 systems
741 which don't have a hardware IOMMU (e.g. the current generation
742 of Intel's x86-64 CPUs). Using this PCI devices which can only
743 access 32-bits of memory can be used on systems with more than
744 3 GB of memory. If unsure, say Y.
747 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
750 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
751 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
752 select CPUMASK_OFFSTACK
754 Enable maximum number of CPUS and NUMA Nodes for this architecture.
758 int "Maximum number of CPUs" if SMP && !MAXSMP
759 range 2 8 if SMP && X86_32 && !X86_BIGSMP
760 range 2 512 if SMP && !MAXSMP
762 default "4096" if MAXSMP
763 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
766 This allows you to specify the maximum number of CPUs which this
767 kernel will support. The maximum supported value is 512 and the
768 minimum value which makes sense is 2.
770 This is purely to save memory - each supported CPU adds
771 approximately eight kilobytes to the kernel image.
774 bool "SMT (Hyperthreading) scheduler support"
777 SMT scheduler support improves the CPU scheduler's decision making
778 when dealing with Intel Pentium 4 chips with HyperThreading at a
779 cost of slightly increased overhead in some places. If unsure say
784 prompt "Multi-core scheduler support"
787 Multi-core scheduler support improves the CPU scheduler's decision
788 making when dealing with multi-core CPU chips at a cost of slightly
789 increased overhead in some places. If unsure say N here.
791 config IRQ_TIME_ACCOUNTING
792 bool "Fine granularity task level IRQ time accounting"
795 Select this option to enable fine granularity task irq time
796 accounting. This is done by reading a timestamp on each
797 transitions between softirq and hardirq state, so there can be a
798 small performance impact.
800 If in doubt, say N here.
802 source "kernel/Kconfig.preempt"
805 bool "Local APIC support on uniprocessors"
806 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
808 A local APIC (Advanced Programmable Interrupt Controller) is an
809 integrated interrupt controller in the CPU. If you have a single-CPU
810 system which has a processor with a local APIC, you can say Y here to
811 enable and use it. If you say Y here even though your machine doesn't
812 have a local APIC, then the kernel will still run with no slowdown at
813 all. The local APIC supports CPU-generated self-interrupts (timer,
814 performance counters), and the NMI watchdog which detects hard
818 bool "IO-APIC support on uniprocessors"
819 depends on X86_UP_APIC
821 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
822 SMP-capable replacement for PC-style interrupt controllers. Most
823 SMP systems and many recent uniprocessor systems have one.
825 If you have a single-CPU system with an IO-APIC, you can say Y here
826 to use it. If you say Y here even though your machine doesn't have
827 an IO-APIC, then the kernel will still run with no slowdown at all.
829 config X86_LOCAL_APIC
831 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
835 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
837 config X86_VISWS_APIC
839 depends on X86_32 && X86_VISWS
841 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
842 bool "Reroute for broken boot IRQs"
843 depends on X86_IO_APIC
845 This option enables a workaround that fixes a source of
846 spurious interrupts. This is recommended when threaded
847 interrupt handling is used on systems where the generation of
848 superfluous "boot interrupts" cannot be disabled.
850 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
851 entry in the chipset's IO-APIC is masked (as, e.g. the RT
852 kernel does during interrupt handling). On chipsets where this
853 boot IRQ generation cannot be disabled, this workaround keeps
854 the original IRQ line masked so that only the equivalent "boot
855 IRQ" is delivered to the CPUs. The workaround also tells the
856 kernel to set up the IRQ handler on the boot IRQ line. In this
857 way only one interrupt is delivered to the kernel. Otherwise
858 the spurious second interrupt may cause the kernel to bring
859 down (vital) interrupt lines.
861 Only affects "broken" chipsets. Interrupt sharing may be
862 increased on these systems.
865 bool "Machine Check / overheating reporting"
867 Machine Check support allows the processor to notify the
868 kernel if it detects a problem (e.g. overheating, data corruption).
869 The action the kernel takes depends on the severity of the problem,
870 ranging from warning messages to halting the machine.
874 prompt "Intel MCE features"
875 depends on X86_MCE && X86_LOCAL_APIC
877 Additional support for intel specific MCE features such as
882 prompt "AMD MCE features"
883 depends on X86_MCE && X86_LOCAL_APIC
885 Additional support for AMD specific MCE features such as
886 the DRAM Error Threshold.
888 config X86_ANCIENT_MCE
889 bool "Support for old Pentium 5 / WinChip machine checks"
890 depends on X86_32 && X86_MCE
892 Include support for machine check handling on old Pentium 5 or WinChip
893 systems. These typically need to be enabled explicitely on the command
896 config X86_MCE_THRESHOLD
897 depends on X86_MCE_AMD || X86_MCE_INTEL
900 config X86_MCE_INJECT
902 tristate "Machine check injector support"
904 Provide support for injecting machine checks for testing purposes.
905 If you don't know what a machine check is and you don't do kernel
906 QA it is safe to say n.
908 config X86_THERMAL_VECTOR
910 depends on X86_MCE_INTEL
913 bool "Enable VM86 support" if EXPERT
917 This option is required by programs like DOSEMU to run 16-bit legacy
918 code on X86 processors. It also may be needed by software like
919 XFree86 to initialize some video cards via BIOS. Disabling this
920 option saves about 6k.
923 tristate "Toshiba Laptop support"
926 This adds a driver to safely access the System Management Mode of
927 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
928 not work on models with a Phoenix BIOS. The System Management Mode
929 is used to set the BIOS and power saving options on Toshiba portables.
931 For information on utilities to make use of this driver see the
932 Toshiba Linux utilities web site at:
933 <http://www.buzzard.org.uk/toshiba/>.
935 Say Y if you intend to run this kernel on a Toshiba portable.
939 tristate "Dell laptop support"
942 This adds a driver to safely access the System Management Mode
943 of the CPU on the Dell Inspiron 8000. The System Management Mode
944 is used to read cpu temperature and cooling fan status and to
945 control the fans on the I8K portables.
947 This driver has been tested only on the Inspiron 8000 but it may
948 also work with other Dell laptops. You can force loading on other
949 models by passing the parameter `force=1' to the module. Use at
952 For information on utilities to make use of this driver see the
953 I8K Linux utilities web site at:
954 <http://people.debian.org/~dz/i8k/>
956 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
959 config X86_REBOOTFIXUPS
960 bool "Enable X86 board specific fixups for reboot"
963 This enables chipset and/or board specific fixups to be done
964 in order to get reboot to work correctly. This is only needed on
965 some combinations of hardware and BIOS. The symptom, for which
966 this config is intended, is when reboot ends with a stalled/hung
969 Currently, the only fixup is for the Geode machines using
970 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
972 Say Y if you want to enable the fixup. Currently, it's safe to
973 enable this option even if you don't need it.
977 tristate "/dev/cpu/microcode - microcode support"
980 If you say Y here, you will be able to update the microcode on
981 certain Intel and AMD processors. The Intel support is for the
982 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
983 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
984 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
985 You will obviously need the actual microcode binary data itself
986 which is not shipped with the Linux kernel.
988 This option selects the general module only, you need to select
989 at least one vendor specific module as well.
991 To compile this driver as a module, choose M here: the
992 module will be called microcode.
994 config MICROCODE_INTEL
995 bool "Intel microcode patch loading support"
1000 This options enables microcode patch loading support for Intel
1003 For latest news and information on obtaining all the required
1004 Intel ingredients for this driver, check:
1005 <http://www.urbanmyth.org/microcode/>.
1007 config MICROCODE_AMD
1008 bool "AMD microcode patch loading support"
1009 depends on MICROCODE
1012 If you select this option, microcode patch loading support for AMD
1013 processors will be enabled.
1015 config MICROCODE_OLD_INTERFACE
1017 depends on MICROCODE
1020 tristate "/dev/cpu/*/msr - Model-specific register support"
1022 This device gives privileged processes access to the x86
1023 Model-Specific Registers (MSRs). It is a character device with
1024 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1025 MSR accesses are directed to a specific CPU on multi-processor
1029 tristate "/dev/cpu/*/cpuid - CPU information support"
1031 This device gives processes access to the x86 CPUID instruction to
1032 be executed on a specific processor. It is a character device
1033 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1037 prompt "High Memory Support"
1038 default HIGHMEM64G if X86_NUMAQ
1044 depends on !X86_NUMAQ
1046 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1047 However, the address space of 32-bit x86 processors is only 4
1048 Gigabytes large. That means that, if you have a large amount of
1049 physical memory, not all of it can be "permanently mapped" by the
1050 kernel. The physical memory that's not permanently mapped is called
1053 If you are compiling a kernel which will never run on a machine with
1054 more than 1 Gigabyte total physical RAM, answer "off" here (default
1055 choice and suitable for most users). This will result in a "3GB/1GB"
1056 split: 3GB are mapped so that each process sees a 3GB virtual memory
1057 space and the remaining part of the 4GB virtual memory space is used
1058 by the kernel to permanently map as much physical memory as
1061 If the machine has between 1 and 4 Gigabytes physical RAM, then
1064 If more than 4 Gigabytes is used then answer "64GB" here. This
1065 selection turns Intel PAE (Physical Address Extension) mode on.
1066 PAE implements 3-level paging on IA32 processors. PAE is fully
1067 supported by Linux, PAE mode is implemented on all recent Intel
1068 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1069 then the kernel will not boot on CPUs that don't support PAE!
1071 The actual amount of total physical memory will either be
1072 auto detected or can be forced by using a kernel command line option
1073 such as "mem=256M". (Try "man bootparam" or see the documentation of
1074 your boot loader (lilo or loadlin) about how to pass options to the
1075 kernel at boot time.)
1077 If unsure, say "off".
1081 depends on !X86_NUMAQ
1083 Select this if you have a 32-bit processor and between 1 and 4
1084 gigabytes of physical RAM.
1088 depends on !M386 && !M486
1091 Select this if you have a 32-bit processor and more than 4
1092 gigabytes of physical RAM.
1097 depends on EXPERIMENTAL
1098 prompt "Memory split" if EXPERT
1102 Select the desired split between kernel and user memory.
1104 If the address range available to the kernel is less than the
1105 physical memory installed, the remaining memory will be available
1106 as "high memory". Accessing high memory is a little more costly
1107 than low memory, as it needs to be mapped into the kernel first.
1108 Note that increasing the kernel address space limits the range
1109 available to user programs, making the address space there
1110 tighter. Selecting anything other than the default 3G/1G split
1111 will also likely make your kernel incompatible with binary-only
1114 If you are not absolutely sure what you are doing, leave this
1118 bool "3G/1G user/kernel split"
1119 config VMSPLIT_3G_OPT
1121 bool "3G/1G user/kernel split (for full 1G low memory)"
1123 bool "2G/2G user/kernel split"
1124 config VMSPLIT_2G_OPT
1126 bool "2G/2G user/kernel split (for full 2G low memory)"
1128 bool "1G/3G user/kernel split"
1133 default 0xB0000000 if VMSPLIT_3G_OPT
1134 default 0x80000000 if VMSPLIT_2G
1135 default 0x78000000 if VMSPLIT_2G_OPT
1136 default 0x40000000 if VMSPLIT_1G
1142 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1145 bool "PAE (Physical Address Extension) Support"
1146 depends on X86_32 && !HIGHMEM4G
1148 PAE is required for NX support, and furthermore enables
1149 larger swapspace support for non-overcommit purposes. It
1150 has the cost of more pagetable lookup overhead, and also
1151 consumes more pagetable space per process.
1153 config ARCH_PHYS_ADDR_T_64BIT
1154 def_bool X86_64 || X86_PAE
1156 config ARCH_DMA_ADDR_T_64BIT
1157 def_bool X86_64 || HIGHMEM64G
1159 config DIRECT_GBPAGES
1160 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1164 Allow the kernel linear mapping to use 1GB pages on CPUs that
1165 support it. This can improve the kernel's performance a tiny bit by
1166 reducing TLB pressure. If in doubt, say "Y".
1168 # Common NUMA Features
1170 bool "Numa Memory Allocation and Scheduler Support"
1172 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1173 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1175 Enable NUMA (Non Uniform Memory Access) support.
1177 The kernel will try to allocate memory used by a CPU on the
1178 local memory controller of the CPU and add some more
1179 NUMA awareness to the kernel.
1181 For 64-bit this is recommended if the system is Intel Core i7
1182 (or later), AMD Opteron, or EM64T NUMA.
1184 For 32-bit this is only needed on (rare) 32-bit-only platforms
1185 that support NUMA topologies, such as NUMAQ / Summit, or if you
1186 boot a 32-bit kernel on a 64-bit NUMA platform.
1188 Otherwise, you should say N.
1190 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1191 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1195 prompt "Old style AMD Opteron NUMA detection"
1196 depends on X86_64 && NUMA && PCI
1198 Enable AMD NUMA node topology detection. You should say Y here if
1199 you have a multi processor AMD system. This uses an old method to
1200 read the NUMA configuration directly from the builtin Northbridge
1201 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1202 which also takes priority if both are compiled in.
1204 config X86_64_ACPI_NUMA
1206 prompt "ACPI NUMA detection"
1207 depends on X86_64 && NUMA && ACPI && PCI
1210 Enable ACPI SRAT based node topology detection.
1212 # Some NUMA nodes have memory ranges that span
1213 # other nodes. Even though a pfn is valid and
1214 # between a node's start and end pfns, it may not
1215 # reside on that node. See memmap_init_zone()
1217 config NODES_SPAN_OTHER_NODES
1219 depends on X86_64_ACPI_NUMA
1222 bool "NUMA emulation"
1225 Enable NUMA emulation. A flat machine will be split
1226 into virtual nodes when booted with "numa=fake=N", where N is the
1227 number of nodes. This is only useful for debugging.
1230 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1232 default "10" if MAXSMP
1233 default "6" if X86_64
1234 default "4" if X86_NUMAQ
1236 depends on NEED_MULTIPLE_NODES
1238 Specify the maximum number of NUMA Nodes available on the target
1239 system. Increases memory reserved to accommodate various tables.
1241 config HAVE_ARCH_ALLOC_REMAP
1243 depends on X86_32 && NUMA
1245 config ARCH_HAVE_MEMORY_PRESENT
1247 depends on X86_32 && DISCONTIGMEM
1249 config NEED_NODE_MEMMAP_SIZE
1251 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1253 config ARCH_FLATMEM_ENABLE
1255 depends on X86_32 && !NUMA
1257 config ARCH_DISCONTIGMEM_ENABLE
1259 depends on NUMA && X86_32
1261 config ARCH_DISCONTIGMEM_DEFAULT
1263 depends on NUMA && X86_32
1265 config ARCH_SPARSEMEM_ENABLE
1267 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1268 select SPARSEMEM_STATIC if X86_32
1269 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1271 config ARCH_SPARSEMEM_DEFAULT
1275 config ARCH_SELECT_MEMORY_MODEL
1277 depends on ARCH_SPARSEMEM_ENABLE
1279 config ARCH_MEMORY_PROBE
1281 depends on MEMORY_HOTPLUG
1283 config ARCH_PROC_KCORE_TEXT
1285 depends on X86_64 && PROC_KCORE
1287 config ILLEGAL_POINTER_VALUE
1290 default 0xdead000000000000 if X86_64
1295 bool "Allocate 3rd-level pagetables from highmem"
1298 The VM uses one page table entry for each page of physical memory.
1299 For systems with a lot of RAM, this can be wasteful of precious
1300 low memory. Setting this option will put user-space page table
1301 entries in high memory.
1303 config X86_CHECK_BIOS_CORRUPTION
1304 bool "Check for low memory corruption"
1306 Periodically check for memory corruption in low memory, which
1307 is suspected to be caused by BIOS. Even when enabled in the
1308 configuration, it is disabled at runtime. Enable it by
1309 setting "memory_corruption_check=1" on the kernel command
1310 line. By default it scans the low 64k of memory every 60
1311 seconds; see the memory_corruption_check_size and
1312 memory_corruption_check_period parameters in
1313 Documentation/kernel-parameters.txt to adjust this.
1315 When enabled with the default parameters, this option has
1316 almost no overhead, as it reserves a relatively small amount
1317 of memory and scans it infrequently. It both detects corruption
1318 and prevents it from affecting the running system.
1320 It is, however, intended as a diagnostic tool; if repeatable
1321 BIOS-originated corruption always affects the same memory,
1322 you can use memmap= to prevent the kernel from using that
1325 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1326 bool "Set the default setting of memory_corruption_check"
1327 depends on X86_CHECK_BIOS_CORRUPTION
1330 Set whether the default state of memory_corruption_check is
1333 config X86_RESERVE_LOW
1334 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1338 Specify the amount of low memory to reserve for the BIOS.
1340 The first page contains BIOS data structures that the kernel
1341 must not use, so that page must always be reserved.
1343 By default we reserve the first 64K of physical RAM, as a
1344 number of BIOSes are known to corrupt that memory range
1345 during events such as suspend/resume or monitor cable
1346 insertion, so it must not be used by the kernel.
1348 You can set this to 4 if you are absolutely sure that you
1349 trust the BIOS to get all its memory reservations and usages
1350 right. If you know your BIOS have problems beyond the
1351 default 64K area, you can set this to 640 to avoid using the
1352 entire low memory range.
1354 If you have doubts about the BIOS (e.g. suspend/resume does
1355 not work or there's kernel crashes after certain hardware
1356 hotplug events) then you might want to enable
1357 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1358 typical corruption patterns.
1360 Leave this to the default value of 64 if you are unsure.
1362 config MATH_EMULATION
1364 prompt "Math emulation" if X86_32
1366 Linux can emulate a math coprocessor (used for floating point
1367 operations) if you don't have one. 486DX and Pentium processors have
1368 a math coprocessor built in, 486SX and 386 do not, unless you added
1369 a 487DX or 387, respectively. (The messages during boot time can
1370 give you some hints here ["man dmesg"].) Everyone needs either a
1371 coprocessor or this emulation.
1373 If you don't have a math coprocessor, you need to say Y here; if you
1374 say Y here even though you have a coprocessor, the coprocessor will
1375 be used nevertheless. (This behavior can be changed with the kernel
1376 command line option "no387", which comes handy if your coprocessor
1377 is broken. Try "man bootparam" or see the documentation of your boot
1378 loader (lilo or loadlin) about how to pass options to the kernel at
1379 boot time.) This means that it is a good idea to say Y here if you
1380 intend to use this kernel on different machines.
1382 More information about the internals of the Linux math coprocessor
1383 emulation can be found in <file:arch/x86/math-emu/README>.
1385 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1386 kernel, it won't hurt.
1390 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1392 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1393 the Memory Type Range Registers (MTRRs) may be used to control
1394 processor access to memory ranges. This is most useful if you have
1395 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1396 allows bus write transfers to be combined into a larger transfer
1397 before bursting over the PCI/AGP bus. This can increase performance
1398 of image write operations 2.5 times or more. Saying Y here creates a
1399 /proc/mtrr file which may be used to manipulate your processor's
1400 MTRRs. Typically the X server should use this.
1402 This code has a reasonably generic interface so that similar
1403 control registers on other processors can be easily supported
1406 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1407 Registers (ARRs) which provide a similar functionality to MTRRs. For
1408 these, the ARRs are used to emulate the MTRRs.
1409 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1410 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1411 write-combining. All of these processors are supported by this code
1412 and it makes sense to say Y here if you have one of them.
1414 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1415 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1416 can lead to all sorts of problems, so it's good to say Y here.
1418 You can safely say Y even if your machine doesn't have MTRRs, you'll
1419 just add about 9 KB to your kernel.
1421 See <file:Documentation/x86/mtrr.txt> for more information.
1423 config MTRR_SANITIZER
1425 prompt "MTRR cleanup support"
1428 Convert MTRR layout from continuous to discrete, so X drivers can
1429 add writeback entries.
1431 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1432 The largest mtrr entry size for a continuous block can be set with
1437 config MTRR_SANITIZER_ENABLE_DEFAULT
1438 int "MTRR cleanup enable value (0-1)"
1441 depends on MTRR_SANITIZER
1443 Enable mtrr cleanup default value
1445 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1446 int "MTRR cleanup spare reg num (0-7)"
1449 depends on MTRR_SANITIZER
1451 mtrr cleanup spare entries default, it can be changed via
1452 mtrr_spare_reg_nr=N on the kernel command line.
1456 prompt "x86 PAT support" if EXPERT
1459 Use PAT attributes to setup page level cache control.
1461 PATs are the modern equivalents of MTRRs and are much more
1462 flexible than MTRRs.
1464 Say N here if you see bootup problems (boot crash, boot hang,
1465 spontaneous reboots) or a non-working video driver.
1469 config ARCH_USES_PG_UNCACHED
1475 prompt "x86 architectural random number generator" if EXPERT
1477 Enable the x86 architectural RDRAND instruction
1478 (Intel Bull Mountain technology) to generate random numbers.
1479 If supported, this is a high bandwidth, cryptographically
1480 secure hardware random number generator.
1483 bool "EFI runtime service support"
1486 This enables the kernel to use EFI runtime services that are
1487 available (such as the EFI variable services).
1489 This option is only useful on systems that have EFI firmware.
1490 In addition, you should use the latest ELILO loader available
1491 at <http://elilo.sourceforge.net> in order to take advantage
1492 of EFI runtime services. However, even with this option, the
1493 resultant kernel should continue to boot on existing non-EFI
1497 bool "EFI stub support"
1500 This kernel feature allows a bzImage to be loaded directly
1501 by EFI firmware without the use of a bootloader.
1505 prompt "Enable seccomp to safely compute untrusted bytecode"
1507 This kernel feature is useful for number crunching applications
1508 that may need to compute untrusted bytecode during their
1509 execution. By using pipes or other transports made available to
1510 the process as file descriptors supporting the read/write
1511 syscalls, it's possible to isolate those applications in
1512 their own address space using seccomp. Once seccomp is
1513 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1514 and the task is only allowed to execute a few safe syscalls
1515 defined by each seccomp mode.
1517 If unsure, say Y. Only embedded should say N here.
1519 config CC_STACKPROTECTOR
1520 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1522 This option turns on the -fstack-protector GCC feature. This
1523 feature puts, at the beginning of functions, a canary value on
1524 the stack just before the return address, and validates
1525 the value just before actually returning. Stack based buffer
1526 overflows (that need to overwrite this return address) now also
1527 overwrite the canary, which gets detected and the attack is then
1528 neutralized via a kernel panic.
1530 This feature requires gcc version 4.2 or above, or a distribution
1531 gcc with the feature backported. Older versions are automatically
1532 detected and for those versions, this configuration option is
1533 ignored. (and a warning is printed during bootup)
1535 source kernel/Kconfig.hz
1538 bool "kexec system call"
1540 kexec is a system call that implements the ability to shutdown your
1541 current kernel, and to start another kernel. It is like a reboot
1542 but it is independent of the system firmware. And like a reboot
1543 you can start any kernel with it, not just Linux.
1545 The name comes from the similarity to the exec system call.
1547 It is an ongoing process to be certain the hardware in a machine
1548 is properly shutdown, so do not be surprised if this code does not
1549 initially work for you. It may help to enable device hotplugging
1550 support. As of this writing the exact hardware interface is
1551 strongly in flux, so no good recommendation can be made.
1554 bool "kernel crash dumps"
1555 depends on X86_64 || (X86_32 && HIGHMEM)
1557 Generate crash dump after being started by kexec.
1558 This should be normally only set in special crash dump kernels
1559 which are loaded in the main kernel with kexec-tools into
1560 a specially reserved region and then later executed after
1561 a crash by kdump/kexec. The crash dump kernel must be compiled
1562 to a memory address not used by the main kernel or BIOS using
1563 PHYSICAL_START, or it must be built as a relocatable image
1564 (CONFIG_RELOCATABLE=y).
1565 For more details see Documentation/kdump/kdump.txt
1568 bool "kexec jump (EXPERIMENTAL)"
1569 depends on EXPERIMENTAL
1570 depends on KEXEC && HIBERNATION
1572 Jump between original kernel and kexeced kernel and invoke
1573 code in physical address mode via KEXEC
1575 config PHYSICAL_START
1576 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1579 This gives the physical address where the kernel is loaded.
1581 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1582 bzImage will decompress itself to above physical address and
1583 run from there. Otherwise, bzImage will run from the address where
1584 it has been loaded by the boot loader and will ignore above physical
1587 In normal kdump cases one does not have to set/change this option
1588 as now bzImage can be compiled as a completely relocatable image
1589 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1590 address. This option is mainly useful for the folks who don't want
1591 to use a bzImage for capturing the crash dump and want to use a
1592 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1593 to be specifically compiled to run from a specific memory area
1594 (normally a reserved region) and this option comes handy.
1596 So if you are using bzImage for capturing the crash dump,
1597 leave the value here unchanged to 0x1000000 and set
1598 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1599 for capturing the crash dump change this value to start of
1600 the reserved region. In other words, it can be set based on
1601 the "X" value as specified in the "crashkernel=YM@XM"
1602 command line boot parameter passed to the panic-ed
1603 kernel. Please take a look at Documentation/kdump/kdump.txt
1604 for more details about crash dumps.
1606 Usage of bzImage for capturing the crash dump is recommended as
1607 one does not have to build two kernels. Same kernel can be used
1608 as production kernel and capture kernel. Above option should have
1609 gone away after relocatable bzImage support is introduced. But it
1610 is present because there are users out there who continue to use
1611 vmlinux for dump capture. This option should go away down the
1614 Don't change this unless you know what you are doing.
1617 bool "Build a relocatable kernel"
1620 This builds a kernel image that retains relocation information
1621 so it can be loaded someplace besides the default 1MB.
1622 The relocations tend to make the kernel binary about 10% larger,
1623 but are discarded at runtime.
1625 One use is for the kexec on panic case where the recovery kernel
1626 must live at a different physical address than the primary
1629 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1630 it has been loaded at and the compile time physical address
1631 (CONFIG_PHYSICAL_START) is ignored.
1633 # Relocation on x86-32 needs some additional build support
1634 config X86_NEED_RELOCS
1636 depends on X86_32 && RELOCATABLE
1638 config PHYSICAL_ALIGN
1639 hex "Alignment value to which kernel should be aligned" if X86_32
1641 range 0x2000 0x1000000
1643 This value puts the alignment restrictions on physical address
1644 where kernel is loaded and run from. Kernel is compiled for an
1645 address which meets above alignment restriction.
1647 If bootloader loads the kernel at a non-aligned address and
1648 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1649 address aligned to above value and run from there.
1651 If bootloader loads the kernel at a non-aligned address and
1652 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1653 load address and decompress itself to the address it has been
1654 compiled for and run from there. The address for which kernel is
1655 compiled already meets above alignment restrictions. Hence the
1656 end result is that kernel runs from a physical address meeting
1657 above alignment restrictions.
1659 Don't change this unless you know what you are doing.
1662 bool "Support for hot-pluggable CPUs"
1663 depends on SMP && HOTPLUG
1665 Say Y here to allow turning CPUs off and on. CPUs can be
1666 controlled through /sys/devices/system/cpu.
1667 ( Note: power management support will enable this option
1668 automatically on SMP systems. )
1669 Say N if you want to disable CPU hotplug.
1673 prompt "Compat VDSO support"
1674 depends on X86_32 || IA32_EMULATION
1676 Map the 32-bit VDSO to the predictable old-style address too.
1678 Say N here if you are running a sufficiently recent glibc
1679 version (2.3.3 or later), to remove the high-mapped
1680 VDSO mapping and to exclusively use the randomized VDSO.
1685 bool "Built-in kernel command line"
1687 Allow for specifying boot arguments to the kernel at
1688 build time. On some systems (e.g. embedded ones), it is
1689 necessary or convenient to provide some or all of the
1690 kernel boot arguments with the kernel itself (that is,
1691 to not rely on the boot loader to provide them.)
1693 To compile command line arguments into the kernel,
1694 set this option to 'Y', then fill in the
1695 the boot arguments in CONFIG_CMDLINE.
1697 Systems with fully functional boot loaders (i.e. non-embedded)
1698 should leave this option set to 'N'.
1701 string "Built-in kernel command string"
1702 depends on CMDLINE_BOOL
1705 Enter arguments here that should be compiled into the kernel
1706 image and used at boot time. If the boot loader provides a
1707 command line at boot time, it is appended to this string to
1708 form the full kernel command line, when the system boots.
1710 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1711 change this behavior.
1713 In most cases, the command line (whether built-in or provided
1714 by the boot loader) should specify the device for the root
1717 config CMDLINE_OVERRIDE
1718 bool "Built-in command line overrides boot loader arguments"
1719 depends on CMDLINE_BOOL
1721 Set this option to 'Y' to have the kernel ignore the boot loader
1722 command line, and use ONLY the built-in command line.
1724 This is used to work around broken boot loaders. This should
1725 be set to 'N' under normal conditions.
1729 config ARCH_ENABLE_MEMORY_HOTPLUG
1731 depends on X86_64 || (X86_32 && HIGHMEM)
1733 config ARCH_ENABLE_MEMORY_HOTREMOVE
1735 depends on MEMORY_HOTPLUG
1737 config USE_PERCPU_NUMA_NODE_ID
1741 menu "Power management and ACPI options"
1743 config ARCH_HIBERNATION_HEADER
1745 depends on X86_64 && HIBERNATION
1747 source "kernel/power/Kconfig"
1749 source "drivers/acpi/Kconfig"
1751 source "drivers/sfi/Kconfig"
1758 tristate "APM (Advanced Power Management) BIOS support"
1759 depends on X86_32 && PM_SLEEP
1761 APM is a BIOS specification for saving power using several different
1762 techniques. This is mostly useful for battery powered laptops with
1763 APM compliant BIOSes. If you say Y here, the system time will be
1764 reset after a RESUME operation, the /proc/apm device will provide
1765 battery status information, and user-space programs will receive
1766 notification of APM "events" (e.g. battery status change).
1768 If you select "Y" here, you can disable actual use of the APM
1769 BIOS by passing the "apm=off" option to the kernel at boot time.
1771 Note that the APM support is almost completely disabled for
1772 machines with more than one CPU.
1774 In order to use APM, you will need supporting software. For location
1775 and more information, read <file:Documentation/power/apm-acpi.txt>
1776 and the Battery Powered Linux mini-HOWTO, available from
1777 <http://www.tldp.org/docs.html#howto>.
1779 This driver does not spin down disk drives (see the hdparm(8)
1780 manpage ("man 8 hdparm") for that), and it doesn't turn off
1781 VESA-compliant "green" monitors.
1783 This driver does not support the TI 4000M TravelMate and the ACER
1784 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1785 desktop machines also don't have compliant BIOSes, and this driver
1786 may cause those machines to panic during the boot phase.
1788 Generally, if you don't have a battery in your machine, there isn't
1789 much point in using this driver and you should say N. If you get
1790 random kernel OOPSes or reboots that don't seem to be related to
1791 anything, try disabling/enabling this option (or disabling/enabling
1794 Some other things you should try when experiencing seemingly random,
1797 1) make sure that you have enough swap space and that it is
1799 2) pass the "no-hlt" option to the kernel
1800 3) switch on floating point emulation in the kernel and pass
1801 the "no387" option to the kernel
1802 4) pass the "floppy=nodma" option to the kernel
1803 5) pass the "mem=4M" option to the kernel (thereby disabling
1804 all but the first 4 MB of RAM)
1805 6) make sure that the CPU is not over clocked.
1806 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1807 8) disable the cache from your BIOS settings
1808 9) install a fan for the video card or exchange video RAM
1809 10) install a better fan for the CPU
1810 11) exchange RAM chips
1811 12) exchange the motherboard.
1813 To compile this driver as a module, choose M here: the
1814 module will be called apm.
1818 config APM_IGNORE_USER_SUSPEND
1819 bool "Ignore USER SUSPEND"
1821 This option will ignore USER SUSPEND requests. On machines with a
1822 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1823 series notebooks, it is necessary to say Y because of a BIOS bug.
1825 config APM_DO_ENABLE
1826 bool "Enable PM at boot time"
1828 Enable APM features at boot time. From page 36 of the APM BIOS
1829 specification: "When disabled, the APM BIOS does not automatically
1830 power manage devices, enter the Standby State, enter the Suspend
1831 State, or take power saving steps in response to CPU Idle calls."
1832 This driver will make CPU Idle calls when Linux is idle (unless this
1833 feature is turned off -- see "Do CPU IDLE calls", below). This
1834 should always save battery power, but more complicated APM features
1835 will be dependent on your BIOS implementation. You may need to turn
1836 this option off if your computer hangs at boot time when using APM
1837 support, or if it beeps continuously instead of suspending. Turn
1838 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1839 T400CDT. This is off by default since most machines do fine without
1843 bool "Make CPU Idle calls when idle"
1845 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1846 On some machines, this can activate improved power savings, such as
1847 a slowed CPU clock rate, when the machine is idle. These idle calls
1848 are made after the idle loop has run for some length of time (e.g.,
1849 333 mS). On some machines, this will cause a hang at boot time or
1850 whenever the CPU becomes idle. (On machines with more than one CPU,
1851 this option does nothing.)
1853 config APM_DISPLAY_BLANK
1854 bool "Enable console blanking using APM"
1856 Enable console blanking using the APM. Some laptops can use this to
1857 turn off the LCD backlight when the screen blanker of the Linux
1858 virtual console blanks the screen. Note that this is only used by
1859 the virtual console screen blanker, and won't turn off the backlight
1860 when using the X Window system. This also doesn't have anything to
1861 do with your VESA-compliant power-saving monitor. Further, this
1862 option doesn't work for all laptops -- it might not turn off your
1863 backlight at all, or it might print a lot of errors to the console,
1864 especially if you are using gpm.
1866 config APM_ALLOW_INTS
1867 bool "Allow interrupts during APM BIOS calls"
1869 Normally we disable external interrupts while we are making calls to
1870 the APM BIOS as a measure to lessen the effects of a badly behaving
1871 BIOS implementation. The BIOS should reenable interrupts if it
1872 needs to. Unfortunately, some BIOSes do not -- especially those in
1873 many of the newer IBM Thinkpads. If you experience hangs when you
1874 suspend, try setting this to Y. Otherwise, say N.
1878 source "drivers/cpufreq/Kconfig"
1880 source "drivers/cpuidle/Kconfig"
1882 source "drivers/idle/Kconfig"
1887 menu "Bus options (PCI etc.)"
1892 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1894 Find out whether you have a PCI motherboard. PCI is the name of a
1895 bus system, i.e. the way the CPU talks to the other stuff inside
1896 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1897 VESA. If you have PCI, say Y, otherwise N.
1900 prompt "PCI access mode"
1901 depends on X86_32 && PCI
1904 On PCI systems, the BIOS can be used to detect the PCI devices and
1905 determine their configuration. However, some old PCI motherboards
1906 have BIOS bugs and may crash if this is done. Also, some embedded
1907 PCI-based systems don't have any BIOS at all. Linux can also try to
1908 detect the PCI hardware directly without using the BIOS.
1910 With this option, you can specify how Linux should detect the
1911 PCI devices. If you choose "BIOS", the BIOS will be used,
1912 if you choose "Direct", the BIOS won't be used, and if you
1913 choose "MMConfig", then PCI Express MMCONFIG will be used.
1914 If you choose "Any", the kernel will try MMCONFIG, then the
1915 direct access method and falls back to the BIOS if that doesn't
1916 work. If unsure, go with the default, which is "Any".
1921 config PCI_GOMMCONFIG
1938 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1940 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1943 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1947 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1951 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1955 depends on PCI && XEN
1963 bool "Support mmconfig PCI config space access"
1964 depends on X86_64 && PCI && ACPI
1966 config PCI_CNB20LE_QUIRK
1967 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1969 depends on PCI && EXPERIMENTAL
1971 Read the PCI windows out of the CNB20LE host bridge. This allows
1972 PCI hotplug to work on systems with the CNB20LE chipset which do
1975 There's no public spec for this chipset, and this functionality
1976 is known to be incomplete.
1978 You should say N unless you know you need this.
1980 source "drivers/pci/pcie/Kconfig"
1982 source "drivers/pci/Kconfig"
1984 # x86_64 have no ISA slots, but can have ISA-style DMA.
1986 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1989 Enables ISA-style DMA support for devices requiring such controllers.
1997 Find out whether you have ISA slots on your motherboard. ISA is the
1998 name of a bus system, i.e. the way the CPU talks to the other stuff
1999 inside your box. Other bus systems are PCI, EISA, MicroChannel
2000 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2001 newer boards don't support it. If you have ISA, say Y, otherwise N.
2007 The Extended Industry Standard Architecture (EISA) bus was
2008 developed as an open alternative to the IBM MicroChannel bus.
2010 The EISA bus provided some of the features of the IBM MicroChannel
2011 bus while maintaining backward compatibility with cards made for
2012 the older ISA bus. The EISA bus saw limited use between 1988 and
2013 1995 when it was made obsolete by the PCI bus.
2015 Say Y here if you are building a kernel for an EISA-based machine.
2019 source "drivers/eisa/Kconfig"
2024 MicroChannel Architecture is found in some IBM PS/2 machines and
2025 laptops. It is a bus system similar to PCI or ISA. See
2026 <file:Documentation/mca.txt> (and especially the web page given
2027 there) before attempting to build an MCA bus kernel.
2029 source "drivers/mca/Kconfig"
2032 tristate "NatSemi SCx200 support"
2034 This provides basic support for National Semiconductor's
2035 (now AMD's) Geode processors. The driver probes for the
2036 PCI-IDs of several on-chip devices, so its a good dependency
2037 for other scx200_* drivers.
2039 If compiled as a module, the driver is named scx200.
2041 config SCx200HR_TIMER
2042 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2046 This driver provides a clocksource built upon the on-chip
2047 27MHz high-resolution timer. Its also a workaround for
2048 NSC Geode SC-1100's buggy TSC, which loses time when the
2049 processor goes idle (as is done by the scheduler). The
2050 other workaround is idle=poll boot option.
2053 bool "One Laptop Per Child support"
2060 Add support for detecting the unique features of the OLPC
2064 bool "OLPC XO-1 Power Management"
2065 depends on OLPC && MFD_CS5535 && PM_SLEEP
2068 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2071 bool "OLPC XO-1 Real Time Clock"
2072 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2074 Add support for the XO-1 real time clock, which can be used as a
2075 programmable wakeup source.
2078 bool "OLPC XO-1 SCI extras"
2079 depends on OLPC && OLPC_XO1_PM
2084 Add support for SCI-based features of the OLPC XO-1 laptop:
2085 - EC-driven system wakeups
2089 - AC adapter status updates
2090 - Battery status updates
2092 config OLPC_XO15_SCI
2093 bool "OLPC XO-1.5 SCI extras"
2094 depends on OLPC && ACPI
2097 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2098 - EC-driven system wakeups
2099 - AC adapter status updates
2100 - Battery status updates
2103 bool "PCEngines ALIX System Support (LED setup)"
2106 This option enables system support for the PCEngines ALIX.
2107 At present this just sets up LEDs for GPIO control on
2108 ALIX2/3/6 boards. However, other system specific setup should
2111 Note: You must still enable the drivers for GPIO and LED support
2112 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2114 Note: You have to set alix.force=1 for boards with Award BIOS.
2117 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2120 This option enables system support for the Soekris Engineering net5501.
2123 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2127 This option enables system support for the Traverse Technologies GEOS.
2133 depends on CPU_SUP_AMD && PCI
2135 source "drivers/pcmcia/Kconfig"
2137 source "drivers/pci/hotplug/Kconfig"
2140 bool "RapidIO support"
2144 If you say Y here, the kernel will include drivers and
2145 infrastructure code to support RapidIO interconnect devices.
2147 source "drivers/rapidio/Kconfig"
2152 menu "Executable file formats / Emulations"
2154 source "fs/Kconfig.binfmt"
2156 config IA32_EMULATION
2157 bool "IA32 Emulation"
2159 select COMPAT_BINFMT_ELF
2161 Include code to run legacy 32-bit programs under a
2162 64-bit kernel. You should likely turn this on, unless you're
2163 100% sure that you don't have any 32-bit programs left.
2166 tristate "IA32 a.out support"
2167 depends on IA32_EMULATION
2169 Support old a.out binaries in the 32bit emulation.
2172 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2173 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2175 Include code to run binaries for the x32 native 32-bit ABI
2176 for 64-bit processors. An x32 process gets access to the
2177 full 64-bit register file and wide data path while leaving
2178 pointers at 32 bits for smaller memory footprint.
2180 You will need a recent binutils (2.22 or later) with
2181 elf32_x86_64 support enabled to compile a kernel with this
2186 depends on IA32_EMULATION || X86_X32
2187 select ARCH_WANT_OLD_COMPAT_IPC
2189 config COMPAT_FOR_U64_ALIGNMENT
2193 config SYSVIPC_COMPAT
2195 depends on COMPAT && SYSVIPC
2199 depends on COMPAT && KEYS
2205 config HAVE_ATOMIC_IOMAP
2209 config HAVE_TEXT_POKE_SMP
2211 select STOP_MACHINE if SMP
2213 source "net/Kconfig"
2215 source "drivers/Kconfig"
2217 source "drivers/firmware/Kconfig"
2221 source "arch/x86/Kconfig.debug"
2223 source "security/Kconfig"
2225 source "crypto/Kconfig"
2227 source "arch/x86/kvm/Kconfig"
2229 source "lib/Kconfig"