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
18 select X86_DEV_DMA_OPS
23 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PCSPKR_PLATFORM
28 select HAVE_PERF_EVENTS
30 select HAVE_IOREMAP_PROT
33 select HAVE_MEMBLOCK_NODE_MAP
34 select ARCH_DISCARD_MEMBLOCK
35 select ARCH_WANT_OPTIONAL_GPIOLIB
36 select ARCH_WANT_FRAME_POINTERS
38 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
39 select HAVE_KRETPROBES
41 select HAVE_FTRACE_MCOUNT_RECORD
42 select HAVE_FENTRY if X86_64
43 select HAVE_C_RECORDMCOUNT
44 select HAVE_DYNAMIC_FTRACE
45 select HAVE_FUNCTION_TRACER
46 select HAVE_FUNCTION_GRAPH_TRACER
47 select HAVE_FUNCTION_GRAPH_FP_TEST
48 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
49 select HAVE_SYSCALL_TRACEPOINTS
50 select SYSCTL_EXCEPTION_TRACE
53 select HAVE_ARCH_TRACEHOOK
54 select HAVE_GENERIC_DMA_COHERENT if X86_32
55 select HAVE_EFFICIENT_UNALIGNED_ACCESS
56 select USER_STACKTRACE_SUPPORT
57 select HAVE_REGS_AND_STACK_ACCESS_API
58 select HAVE_DMA_API_DEBUG
59 select HAVE_KERNEL_GZIP
60 select HAVE_KERNEL_BZIP2
61 select HAVE_KERNEL_LZMA
63 select HAVE_KERNEL_LZO
64 select HAVE_HW_BREAKPOINT
65 select HAVE_MIXED_BREAKPOINTS_REGS
67 select HAVE_PERF_EVENTS_NMI
69 select HAVE_PERF_USER_STACK_DUMP
70 select HAVE_DEBUG_KMEMLEAK
72 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
73 select HAVE_CMPXCHG_LOCAL
74 select HAVE_CMPXCHG_DOUBLE
75 select HAVE_ARCH_KMEMCHECK
76 select HAVE_USER_RETURN_NOTIFIER
77 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
78 select HAVE_ARCH_JUMP_LABEL
79 select HAVE_TEXT_POKE_SMP
80 select HAVE_GENERIC_HARDIRQS
81 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
83 select GENERIC_FIND_FIRST_BIT
84 select GENERIC_IRQ_PROBE
85 select GENERIC_PENDING_IRQ if SMP
86 select GENERIC_IRQ_SHOW
87 select GENERIC_CLOCKEVENTS_MIN_ADJUST
88 select IRQ_FORCED_THREADING
89 select USE_GENERIC_SMP_HELPERS if SMP
90 select HAVE_BPF_JIT if X86_64
91 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
93 select ARCH_HAVE_NMI_SAFE_CMPXCHG
95 select DCACHE_WORD_ACCESS
96 select GENERIC_SMP_IDLE_THREAD
97 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
98 select HAVE_ARCH_SECCOMP_FILTER
99 select BUILDTIME_EXTABLE_SORT
100 select GENERIC_CMOS_UPDATE
101 select CLOCKSOURCE_WATCHDOG
102 select GENERIC_CLOCKEVENTS
103 select ARCH_CLOCKSOURCE_DATA if X86_64
104 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
105 select GENERIC_TIME_VSYSCALL if X86_64
106 select KTIME_SCALAR if X86_32
107 select GENERIC_STRNCPY_FROM_USER
108 select GENERIC_STRNLEN_USER
109 select HAVE_CONTEXT_TRACKING if X86_64
110 select HAVE_IRQ_TIME_ACCOUNTING
111 select GENERIC_KERNEL_THREAD
112 select GENERIC_KERNEL_EXECVE
113 select MODULES_USE_ELF_REL if X86_32
114 select MODULES_USE_ELF_RELA if X86_64
116 config INSTRUCTION_DECODER
118 depends on KPROBES || PERF_EVENTS || UPROBES
122 default "elf32-i386" if X86_32
123 default "elf64-x86-64" if X86_64
125 config ARCH_DEFCONFIG
127 default "arch/x86/configs/i386_defconfig" if X86_32
128 default "arch/x86/configs/x86_64_defconfig" if X86_64
130 config LOCKDEP_SUPPORT
133 config STACKTRACE_SUPPORT
136 config HAVE_LATENCYTOP_SUPPORT
145 config NEED_DMA_MAP_STATE
147 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
149 config NEED_SG_DMA_LENGTH
152 config GENERIC_ISA_DMA
154 depends on ISA_DMA_API
159 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
161 config GENERIC_BUG_RELATIVE_POINTERS
164 config GENERIC_HWEIGHT
170 config ARCH_MAY_HAVE_PC_FDC
172 depends on ISA_DMA_API
174 config RWSEM_XCHGADD_ALGORITHM
177 config GENERIC_CALIBRATE_DELAY
180 config ARCH_HAS_CPU_RELAX
183 config ARCH_HAS_DEFAULT_IDLE
186 config ARCH_HAS_CACHE_LINE_SIZE
189 config ARCH_HAS_CPU_AUTOPROBE
192 config HAVE_SETUP_PER_CPU_AREA
195 config NEED_PER_CPU_EMBED_FIRST_CHUNK
198 config NEED_PER_CPU_PAGE_FIRST_CHUNK
201 config ARCH_HIBERNATION_POSSIBLE
204 config ARCH_SUSPEND_POSSIBLE
215 config ARCH_SUPPORTS_OPTIMIZED_INLINING
218 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
221 config HAVE_INTEL_TXT
223 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
227 depends on X86_32 && SMP
231 depends on X86_64 && SMP
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
241 config ARCH_HWEIGHT_CFLAGS
243 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
244 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
246 config ARCH_CPU_PROBE_RELEASE
248 depends on HOTPLUG_CPU
250 config ARCH_SUPPORTS_UPROBES
253 source "init/Kconfig"
254 source "kernel/Kconfig.freezer"
256 menu "Processor type and features"
259 bool "DMA memory allocation support" if EXPERT
262 DMA memory allocation support allows devices with less than 32-bit
263 addressing to allocate within the first 16MB of address space.
264 Disable if no such devices will be used.
269 bool "Symmetric multi-processing support"
271 This enables support for systems with more than one CPU. If you have
272 a system with only one CPU, like most personal computers, say N. If
273 you have a system with more than one CPU, say Y.
275 If you say N here, the kernel will run on single and multiprocessor
276 machines, but will use only one CPU of a multiprocessor machine. If
277 you say Y here, the kernel will run on many, but not all,
278 singleprocessor machines. On a singleprocessor machine, the kernel
279 will run faster if you say N here.
281 Note that if you say Y here and choose architecture "586" or
282 "Pentium" under "Processor family", the kernel will not work on 486
283 architectures. Similarly, multiprocessor kernels for the "PPro"
284 architecture may not work on all Pentium based boards.
286 People using multiprocessor machines who say Y here should also say
287 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
288 Management" code will be disabled if you say Y here.
290 See also <file:Documentation/x86/i386/IO-APIC.txt>,
291 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
292 <http://www.tldp.org/docs.html#howto>.
294 If you don't know what to do here, say N.
297 bool "Support x2apic"
298 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
300 This enables x2apic support on CPUs that have this feature.
302 This allows 32-bit apic IDs (so it can support very large systems),
303 and accesses the local apic via MSRs not via mmio.
305 If you don't know what to do here, say N.
308 bool "Enable MPS table" if ACPI || SFI
310 depends on X86_LOCAL_APIC
312 For old smp systems that do not have proper acpi support. Newer systems
313 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
316 bool "Support for big SMP systems with more than 8 CPUs"
317 depends on X86_32 && SMP
319 This option is needed for the systems that have more than 8 CPUs
322 config X86_EXTENDED_PLATFORM
323 bool "Support for extended (non-PC) x86 platforms"
326 If you disable this option then the kernel will only support
327 standard PC platforms. (which covers the vast majority of
330 If you enable this option then you'll be able to select support
331 for the following (non-PC) 32 bit x86 platforms:
335 SGI 320/540 (Visual Workstation)
336 STA2X11-based (e.g. Northville)
337 Summit/EXA (IBM x440)
338 Unisys ES7000 IA32 series
339 Moorestown MID devices
341 If you have one of these systems, or if you want to build a
342 generic distribution kernel, say Y here - otherwise say N.
346 config X86_EXTENDED_PLATFORM
347 bool "Support for extended (non-PC) x86 platforms"
350 If you disable this option then the kernel will only support
351 standard PC platforms. (which covers the vast majority of
354 If you enable this option then you'll be able to select support
355 for the following (non-PC) 64 bit x86 platforms:
360 If you have one of these systems, or if you want to build a
361 generic distribution kernel, say Y here - otherwise say N.
363 # This is an alphabetically sorted list of 64 bit extended platforms
364 # Please maintain the alphabetic order if and when there are additions
366 bool "Numascale NumaChip"
368 depends on X86_EXTENDED_PLATFORM
371 depends on X86_X2APIC
373 Adds support for Numascale NumaChip large-SMP systems. Needed to
374 enable more than ~168 cores.
375 If you don't have one of these, you should say N here.
379 select PARAVIRT_GUEST
381 depends on X86_64 && PCI
382 depends on X86_EXTENDED_PLATFORM
385 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
386 supposed to run on these EM64T-based machines. Only choose this option
387 if you have one of these machines.
390 bool "SGI Ultraviolet"
392 depends on X86_EXTENDED_PLATFORM
394 depends on X86_X2APIC
396 This option is needed in order to support SGI Ultraviolet systems.
397 If you don't have one of these, you should say N here.
399 # Following is an alphabetically sorted list of 32 bit extended platforms
400 # Please maintain the alphabetic order if and when there are additions
403 bool "CE4100 TV platform"
405 depends on PCI_GODIRECT
407 depends on X86_EXTENDED_PLATFORM
408 select X86_REBOOTFIXUPS
410 select OF_EARLY_FLATTREE
413 Select for the Intel CE media processor (CE4100) SOC.
414 This option compiles in support for the CE4100 SOC for settop
415 boxes and media devices.
417 config X86_WANT_INTEL_MID
418 bool "Intel MID platform support"
420 depends on X86_EXTENDED_PLATFORM
422 Select to build a kernel capable of supporting Intel MID platform
423 systems which do not have the PCI legacy interfaces (Moorestown,
424 Medfield). If you are building for a PC class system say N here.
426 if X86_WANT_INTEL_MID
432 bool "Medfield MID platform"
435 depends on X86_IO_APIC
443 select X86_PLATFORM_DEVICES
444 select MFD_INTEL_MSIC
446 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
447 Internet Device(MID) platform.
448 Unlike standard x86 PCs, Medfield does not have many legacy devices
449 nor standard legacy replacement devices/features. e.g. Medfield does
450 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
455 bool "RDC R-321x SoC"
457 depends on X86_EXTENDED_PLATFORM
459 select X86_REBOOTFIXUPS
461 This option is needed for RDC R-321x system-on-chip, also known
463 If you don't have one of these chips, you should say N here.
465 config X86_32_NON_STANDARD
466 bool "Support non-standard 32-bit SMP architectures"
467 depends on X86_32 && SMP
468 depends on X86_EXTENDED_PLATFORM
470 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
471 STA2X11, default subarchitectures. It is intended for a generic
472 binary kernel. If you select them all, kernel will probe it
473 one by one and will fallback to default.
475 # Alphabetically sorted list of Non standard 32 bit platforms
478 bool "NUMAQ (IBM/Sequent)"
479 depends on X86_32_NON_STANDARD
484 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
485 NUMA multiquad box. This changes the way that processors are
486 bootstrapped, and uses Clustered Logical APIC addressing mode instead
487 of Flat Logical. You will need a new lynxer.elf file to flash your
488 firmware with - send email to <Martin.Bligh@us.ibm.com>.
490 config X86_SUPPORTS_MEMORY_FAILURE
492 # MCE code calls memory_failure():
494 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
495 depends on !X86_NUMAQ
496 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
497 depends on X86_64 || !SPARSEMEM
498 select ARCH_SUPPORTS_MEMORY_FAILURE
501 bool "SGI 320/540 (Visual Workstation)"
502 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
503 depends on X86_32_NON_STANDARD
505 The SGI Visual Workstation series is an IA32-based workstation
506 based on SGI systems chips with some legacy PC hardware attached.
508 Say Y here to create a kernel to run on the SGI 320 or 540.
510 A kernel compiled for the Visual Workstation will run on general
511 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
514 bool "STA2X11 Companion Chip Support"
515 depends on X86_32_NON_STANDARD && PCI
516 select X86_DEV_DMA_OPS
520 select ARCH_REQUIRE_GPIOLIB
523 This adds support for boards based on the STA2X11 IO-Hub,
524 a.k.a. "ConneXt". The chip is used in place of the standard
525 PC chipset, so all "standard" peripherals are missing. If this
526 option is selected the kernel will still be able to boot on
527 standard PC machines.
530 bool "Summit/EXA (IBM x440)"
531 depends on X86_32_NON_STANDARD
533 This option is needed for IBM systems that use the Summit/EXA chipset.
534 In particular, it is needed for the x440.
537 bool "Unisys ES7000 IA32 series"
538 depends on X86_32_NON_STANDARD && X86_BIGSMP
540 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
541 supposed to run on an IA32-based Unisys ES7000 system.
544 tristate "Eurobraille/Iris poweroff module"
547 The Iris machines from EuroBraille do not have APM or ACPI support
548 to shut themselves down properly. A special I/O sequence is
549 needed to do so, which is what this module does at
552 This is only for Iris machines from EuroBraille.
556 config SCHED_OMIT_FRAME_POINTER
558 prompt "Single-depth WCHAN output"
561 Calculate simpler /proc/<PID>/wchan values. If this option
562 is disabled then wchan values will recurse back to the
563 caller function. This provides more accurate wchan values,
564 at the expense of slightly more scheduling overhead.
566 If in doubt, say "Y".
568 menuconfig PARAVIRT_GUEST
569 bool "Paravirtualized guest support"
571 Say Y here to get to see options related to running Linux under
572 various hypervisors. This option alone does not add any kernel code.
574 If you say N, all options in this submenu will be skipped and disabled.
578 config PARAVIRT_TIME_ACCOUNTING
579 bool "Paravirtual steal time accounting"
583 Select this option to enable fine granularity task steal time
584 accounting. Time spent executing other tasks in parallel with
585 the current vCPU is discounted from the vCPU power. To account for
586 that, there can be a small performance impact.
588 If in doubt, say N here.
590 source "arch/x86/xen/Kconfig"
593 bool "KVM Guest support (including kvmclock)"
596 select PARAVIRT_CLOCK
597 default y if PARAVIRT_GUEST
599 This option enables various optimizations for running under the KVM
600 hypervisor. It includes a paravirtualized clock, so that instead
601 of relying on a PIT (or probably other) emulation by the
602 underlying device model, the host provides the guest with
603 timing infrastructure such as time of day, and system time
605 source "arch/x86/lguest/Kconfig"
608 bool "Enable paravirtualization code"
610 This changes the kernel so it can modify itself when it is run
611 under a hypervisor, potentially improving performance significantly
612 over full virtualization. However, when run without a hypervisor
613 the kernel is theoretically slower and slightly larger.
615 config PARAVIRT_SPINLOCKS
616 bool "Paravirtualization layer for spinlocks"
617 depends on PARAVIRT && SMP && EXPERIMENTAL
619 Paravirtualized spinlocks allow a pvops backend to replace the
620 spinlock implementation with something virtualization-friendly
621 (for example, block the virtual CPU rather than spinning).
623 Unfortunately the downside is an up to 5% performance hit on
624 native kernels, with various workloads.
626 If you are unsure how to answer this question, answer N.
628 config PARAVIRT_CLOCK
633 config PARAVIRT_DEBUG
634 bool "paravirt-ops debugging"
635 depends on PARAVIRT && DEBUG_KERNEL
637 Enable to debug paravirt_ops internals. Specifically, BUG if
638 a paravirt_op is missing when it is called.
646 This option adds a kernel parameter 'memtest', which allows memtest
648 memtest=0, mean disabled; -- default
649 memtest=1, mean do 1 test pattern;
651 memtest=4, mean do 4 test patterns.
652 If you are unsure how to answer this question, answer N.
654 config X86_SUMMIT_NUMA
656 depends on X86_32 && NUMA && X86_32_NON_STANDARD
658 config X86_CYCLONE_TIMER
660 depends on X86_SUMMIT
662 source "arch/x86/Kconfig.cpu"
666 prompt "HPET Timer Support" if X86_32
668 Use the IA-PC HPET (High Precision Event Timer) to manage
669 time in preference to the PIT and RTC, if a HPET is
671 HPET is the next generation timer replacing legacy 8254s.
672 The HPET provides a stable time base on SMP
673 systems, unlike the TSC, but it is more expensive to access,
674 as it is off-chip. You can find the HPET spec at
675 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
677 You can safely choose Y here. However, HPET will only be
678 activated if the platform and the BIOS support this feature.
679 Otherwise the 8254 will be used for timing services.
681 Choose N to continue using the legacy 8254 timer.
683 config HPET_EMULATE_RTC
685 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
688 def_bool y if X86_INTEL_MID
689 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
691 depends on X86_INTEL_MID && SFI
693 APB timer is the replacement for 8254, HPET on X86 MID platforms.
694 The APBT provides a stable time base on SMP
695 systems, unlike the TSC, but it is more expensive to access,
696 as it is off-chip. APB timers are always running regardless of CPU
697 C states, they are used as per CPU clockevent device when possible.
699 # Mark as expert because too many people got it wrong.
700 # The code disables itself when not needed.
703 bool "Enable DMI scanning" if EXPERT
705 Enabled scanning of DMI to identify machine quirks. Say Y
706 here unless you have verified that your setup is not
707 affected by entries in the DMI blacklist. Required by PNP
711 bool "GART IOMMU support" if EXPERT
714 depends on X86_64 && PCI && AMD_NB
716 Support for full DMA access of devices with 32bit memory access only
717 on systems with more than 3GB. This is usually needed for USB,
718 sound, many IDE/SATA chipsets and some other devices.
719 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
720 based hardware IOMMU and a software bounce buffer based IOMMU used
721 on Intel systems and as fallback.
722 The code is only active when needed (enough memory and limited
723 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
727 bool "IBM Calgary IOMMU support"
729 depends on X86_64 && PCI && EXPERIMENTAL
731 Support for hardware IOMMUs in IBM's xSeries x366 and x460
732 systems. Needed to run systems with more than 3GB of memory
733 properly with 32-bit PCI devices that do not support DAC
734 (Double Address Cycle). Calgary also supports bus level
735 isolation, where all DMAs pass through the IOMMU. This
736 prevents them from going anywhere except their intended
737 destination. This catches hard-to-find kernel bugs and
738 mis-behaving drivers and devices that do not use the DMA-API
739 properly to set up their DMA buffers. The IOMMU can be
740 turned off at boot time with the iommu=off parameter.
741 Normally the kernel will make the right choice by itself.
744 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
746 prompt "Should Calgary be enabled by default?"
747 depends on CALGARY_IOMMU
749 Should Calgary be enabled by default? if you choose 'y', Calgary
750 will be used (if it exists). If you choose 'n', Calgary will not be
751 used even if it exists. If you choose 'n' and would like to use
752 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
755 # need this always selected by IOMMU for the VIA workaround
759 Support for software bounce buffers used on x86-64 systems
760 which don't have a hardware IOMMU. Using this PCI devices
761 which can only access 32-bits of memory can be used on systems
762 with more than 3 GB of memory.
767 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
770 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
771 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
772 select CPUMASK_OFFSTACK
774 Enable maximum number of CPUS and NUMA Nodes for this architecture.
778 int "Maximum number of CPUs" if SMP && !MAXSMP
779 range 2 8 if SMP && X86_32 && !X86_BIGSMP
780 range 2 512 if SMP && !MAXSMP
782 default "4096" if MAXSMP
783 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
786 This allows you to specify the maximum number of CPUs which this
787 kernel will support. The maximum supported value is 512 and the
788 minimum value which makes sense is 2.
790 This is purely to save memory - each supported CPU adds
791 approximately eight kilobytes to the kernel image.
794 bool "SMT (Hyperthreading) scheduler support"
797 SMT scheduler support improves the CPU scheduler's decision making
798 when dealing with Intel Pentium 4 chips with HyperThreading at a
799 cost of slightly increased overhead in some places. If unsure say
804 prompt "Multi-core scheduler support"
807 Multi-core scheduler support improves the CPU scheduler's decision
808 making when dealing with multi-core CPU chips at a cost of slightly
809 increased overhead in some places. If unsure say N here.
811 source "kernel/Kconfig.preempt"
814 bool "Local APIC support on uniprocessors"
815 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
817 A local APIC (Advanced Programmable Interrupt Controller) is an
818 integrated interrupt controller in the CPU. If you have a single-CPU
819 system which has a processor with a local APIC, you can say Y here to
820 enable and use it. If you say Y here even though your machine doesn't
821 have a local APIC, then the kernel will still run with no slowdown at
822 all. The local APIC supports CPU-generated self-interrupts (timer,
823 performance counters), and the NMI watchdog which detects hard
827 bool "IO-APIC support on uniprocessors"
828 depends on X86_UP_APIC
830 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
831 SMP-capable replacement for PC-style interrupt controllers. Most
832 SMP systems and many recent uniprocessor systems have one.
834 If you have a single-CPU system with an IO-APIC, you can say Y here
835 to use it. If you say Y here even though your machine doesn't have
836 an IO-APIC, then the kernel will still run with no slowdown at all.
838 config X86_LOCAL_APIC
840 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
844 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
846 config X86_VISWS_APIC
848 depends on X86_32 && X86_VISWS
850 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
851 bool "Reroute for broken boot IRQs"
852 depends on X86_IO_APIC
854 This option enables a workaround that fixes a source of
855 spurious interrupts. This is recommended when threaded
856 interrupt handling is used on systems where the generation of
857 superfluous "boot interrupts" cannot be disabled.
859 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
860 entry in the chipset's IO-APIC is masked (as, e.g. the RT
861 kernel does during interrupt handling). On chipsets where this
862 boot IRQ generation cannot be disabled, this workaround keeps
863 the original IRQ line masked so that only the equivalent "boot
864 IRQ" is delivered to the CPUs. The workaround also tells the
865 kernel to set up the IRQ handler on the boot IRQ line. In this
866 way only one interrupt is delivered to the kernel. Otherwise
867 the spurious second interrupt may cause the kernel to bring
868 down (vital) interrupt lines.
870 Only affects "broken" chipsets. Interrupt sharing may be
871 increased on these systems.
874 bool "Machine Check / overheating reporting"
877 Machine Check support allows the processor to notify the
878 kernel if it detects a problem (e.g. overheating, data corruption).
879 The action the kernel takes depends on the severity of the problem,
880 ranging from warning messages to halting the machine.
884 prompt "Intel MCE features"
885 depends on X86_MCE && X86_LOCAL_APIC
887 Additional support for intel specific MCE features such as
892 prompt "AMD MCE features"
893 depends on X86_MCE && X86_LOCAL_APIC
895 Additional support for AMD specific MCE features such as
896 the DRAM Error Threshold.
898 config X86_ANCIENT_MCE
899 bool "Support for old Pentium 5 / WinChip machine checks"
900 depends on X86_32 && X86_MCE
902 Include support for machine check handling on old Pentium 5 or WinChip
903 systems. These typically need to be enabled explicitely on the command
906 config X86_MCE_THRESHOLD
907 depends on X86_MCE_AMD || X86_MCE_INTEL
910 config X86_MCE_INJECT
912 tristate "Machine check injector support"
914 Provide support for injecting machine checks for testing purposes.
915 If you don't know what a machine check is and you don't do kernel
916 QA it is safe to say n.
918 config X86_THERMAL_VECTOR
920 depends on X86_MCE_INTEL
923 bool "Enable VM86 support" if EXPERT
927 This option is required by programs like DOSEMU to run 16-bit legacy
928 code on X86 processors. It also may be needed by software like
929 XFree86 to initialize some video cards via BIOS. Disabling this
930 option saves about 6k.
933 tristate "Toshiba Laptop support"
936 This adds a driver to safely access the System Management Mode of
937 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
938 not work on models with a Phoenix BIOS. The System Management Mode
939 is used to set the BIOS and power saving options on Toshiba portables.
941 For information on utilities to make use of this driver see the
942 Toshiba Linux utilities web site at:
943 <http://www.buzzard.org.uk/toshiba/>.
945 Say Y if you intend to run this kernel on a Toshiba portable.
949 tristate "Dell laptop support"
952 This adds a driver to safely access the System Management Mode
953 of the CPU on the Dell Inspiron 8000. The System Management Mode
954 is used to read cpu temperature and cooling fan status and to
955 control the fans on the I8K portables.
957 This driver has been tested only on the Inspiron 8000 but it may
958 also work with other Dell laptops. You can force loading on other
959 models by passing the parameter `force=1' to the module. Use at
962 For information on utilities to make use of this driver see the
963 I8K Linux utilities web site at:
964 <http://people.debian.org/~dz/i8k/>
966 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
969 config X86_REBOOTFIXUPS
970 bool "Enable X86 board specific fixups for reboot"
973 This enables chipset and/or board specific fixups to be done
974 in order to get reboot to work correctly. This is only needed on
975 some combinations of hardware and BIOS. The symptom, for which
976 this config is intended, is when reboot ends with a stalled/hung
979 Currently, the only fixup is for the Geode machines using
980 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
982 Say Y if you want to enable the fixup. Currently, it's safe to
983 enable this option even if you don't need it.
987 tristate "CPU microcode loading support"
991 If you say Y here, you will be able to update the microcode on
992 certain Intel and AMD processors. The Intel support is for the
993 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
994 Xeon etc. The AMD support is for families 0x10 and later. You will
995 obviously need the actual microcode binary data itself which is not
996 shipped with the Linux kernel.
998 This option selects the general module only, you need to select
999 at least one vendor specific module as well.
1001 To compile this driver as a module, choose M here: the module
1002 will be called microcode.
1004 config MICROCODE_INTEL
1005 bool "Intel microcode loading support"
1006 depends on MICROCODE
1010 This options enables microcode patch loading support for Intel
1013 For latest news and information on obtaining all the required
1014 Intel ingredients for this driver, check:
1015 <http://www.urbanmyth.org/microcode/>.
1017 config MICROCODE_AMD
1018 bool "AMD microcode loading support"
1019 depends on MICROCODE
1022 If you select this option, microcode patch loading support for AMD
1023 processors will be enabled.
1025 config MICROCODE_OLD_INTERFACE
1027 depends on MICROCODE
1030 tristate "/dev/cpu/*/msr - Model-specific register support"
1032 This device gives privileged processes access to the x86
1033 Model-Specific Registers (MSRs). It is a character device with
1034 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1035 MSR accesses are directed to a specific CPU on multi-processor
1039 tristate "/dev/cpu/*/cpuid - CPU information support"
1041 This device gives processes access to the x86 CPUID instruction to
1042 be executed on a specific processor. It is a character device
1043 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1047 prompt "High Memory Support"
1048 default HIGHMEM64G if X86_NUMAQ
1054 depends on !X86_NUMAQ
1056 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1057 However, the address space of 32-bit x86 processors is only 4
1058 Gigabytes large. That means that, if you have a large amount of
1059 physical memory, not all of it can be "permanently mapped" by the
1060 kernel. The physical memory that's not permanently mapped is called
1063 If you are compiling a kernel which will never run on a machine with
1064 more than 1 Gigabyte total physical RAM, answer "off" here (default
1065 choice and suitable for most users). This will result in a "3GB/1GB"
1066 split: 3GB are mapped so that each process sees a 3GB virtual memory
1067 space and the remaining part of the 4GB virtual memory space is used
1068 by the kernel to permanently map as much physical memory as
1071 If the machine has between 1 and 4 Gigabytes physical RAM, then
1074 If more than 4 Gigabytes is used then answer "64GB" here. This
1075 selection turns Intel PAE (Physical Address Extension) mode on.
1076 PAE implements 3-level paging on IA32 processors. PAE is fully
1077 supported by Linux, PAE mode is implemented on all recent Intel
1078 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1079 then the kernel will not boot on CPUs that don't support PAE!
1081 The actual amount of total physical memory will either be
1082 auto detected or can be forced by using a kernel command line option
1083 such as "mem=256M". (Try "man bootparam" or see the documentation of
1084 your boot loader (lilo or loadlin) about how to pass options to the
1085 kernel at boot time.)
1087 If unsure, say "off".
1091 depends on !X86_NUMAQ
1093 Select this if you have a 32-bit processor and between 1 and 4
1094 gigabytes of physical RAM.
1101 Select this if you have a 32-bit processor and more than 4
1102 gigabytes of physical RAM.
1107 depends on EXPERIMENTAL
1108 prompt "Memory split" if EXPERT
1112 Select the desired split between kernel and user memory.
1114 If the address range available to the kernel is less than the
1115 physical memory installed, the remaining memory will be available
1116 as "high memory". Accessing high memory is a little more costly
1117 than low memory, as it needs to be mapped into the kernel first.
1118 Note that increasing the kernel address space limits the range
1119 available to user programs, making the address space there
1120 tighter. Selecting anything other than the default 3G/1G split
1121 will also likely make your kernel incompatible with binary-only
1124 If you are not absolutely sure what you are doing, leave this
1128 bool "3G/1G user/kernel split"
1129 config VMSPLIT_3G_OPT
1131 bool "3G/1G user/kernel split (for full 1G low memory)"
1133 bool "2G/2G user/kernel split"
1134 config VMSPLIT_2G_OPT
1136 bool "2G/2G user/kernel split (for full 2G low memory)"
1138 bool "1G/3G user/kernel split"
1143 default 0xB0000000 if VMSPLIT_3G_OPT
1144 default 0x80000000 if VMSPLIT_2G
1145 default 0x78000000 if VMSPLIT_2G_OPT
1146 default 0x40000000 if VMSPLIT_1G
1152 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1155 bool "PAE (Physical Address Extension) Support"
1156 depends on X86_32 && !HIGHMEM4G
1158 PAE is required for NX support, and furthermore enables
1159 larger swapspace support for non-overcommit purposes. It
1160 has the cost of more pagetable lookup overhead, and also
1161 consumes more pagetable space per process.
1163 config ARCH_PHYS_ADDR_T_64BIT
1165 depends on X86_64 || X86_PAE
1167 config ARCH_DMA_ADDR_T_64BIT
1169 depends on X86_64 || HIGHMEM64G
1171 config DIRECT_GBPAGES
1172 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1176 Allow the kernel linear mapping to use 1GB pages on CPUs that
1177 support it. This can improve the kernel's performance a tiny bit by
1178 reducing TLB pressure. If in doubt, say "Y".
1180 # Common NUMA Features
1182 bool "Numa Memory Allocation and Scheduler Support"
1184 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1185 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1187 Enable NUMA (Non Uniform Memory Access) support.
1189 The kernel will try to allocate memory used by a CPU on the
1190 local memory controller of the CPU and add some more
1191 NUMA awareness to the kernel.
1193 For 64-bit this is recommended if the system is Intel Core i7
1194 (or later), AMD Opteron, or EM64T NUMA.
1196 For 32-bit this is only needed on (rare) 32-bit-only platforms
1197 that support NUMA topologies, such as NUMAQ / Summit, or if you
1198 boot a 32-bit kernel on a 64-bit NUMA platform.
1200 Otherwise, you should say N.
1202 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1203 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1207 prompt "Old style AMD Opteron NUMA detection"
1208 depends on X86_64 && NUMA && PCI
1210 Enable AMD NUMA node topology detection. You should say Y here if
1211 you have a multi processor AMD system. This uses an old method to
1212 read the NUMA configuration directly from the builtin Northbridge
1213 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1214 which also takes priority if both are compiled in.
1216 config X86_64_ACPI_NUMA
1218 prompt "ACPI NUMA detection"
1219 depends on X86_64 && NUMA && ACPI && PCI
1222 Enable ACPI SRAT based node topology detection.
1224 # Some NUMA nodes have memory ranges that span
1225 # other nodes. Even though a pfn is valid and
1226 # between a node's start and end pfns, it may not
1227 # reside on that node. See memmap_init_zone()
1229 config NODES_SPAN_OTHER_NODES
1231 depends on X86_64_ACPI_NUMA
1234 bool "NUMA emulation"
1237 Enable NUMA emulation. A flat machine will be split
1238 into virtual nodes when booted with "numa=fake=N", where N is the
1239 number of nodes. This is only useful for debugging.
1242 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1244 default "10" if MAXSMP
1245 default "6" if X86_64
1246 default "4" if X86_NUMAQ
1248 depends on NEED_MULTIPLE_NODES
1250 Specify the maximum number of NUMA Nodes available on the target
1251 system. Increases memory reserved to accommodate various tables.
1253 config HAVE_ARCH_ALLOC_REMAP
1255 depends on X86_32 && NUMA
1257 config ARCH_HAVE_MEMORY_PRESENT
1259 depends on X86_32 && DISCONTIGMEM
1261 config NEED_NODE_MEMMAP_SIZE
1263 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1265 config ARCH_FLATMEM_ENABLE
1267 depends on X86_32 && !NUMA
1269 config ARCH_DISCONTIGMEM_ENABLE
1271 depends on NUMA && X86_32
1273 config ARCH_DISCONTIGMEM_DEFAULT
1275 depends on NUMA && X86_32
1277 config ARCH_SPARSEMEM_ENABLE
1279 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1280 select SPARSEMEM_STATIC if X86_32
1281 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1283 config ARCH_SPARSEMEM_DEFAULT
1287 config ARCH_SELECT_MEMORY_MODEL
1289 depends on ARCH_SPARSEMEM_ENABLE
1291 config ARCH_MEMORY_PROBE
1293 depends on X86_64 && MEMORY_HOTPLUG
1295 config ARCH_PROC_KCORE_TEXT
1297 depends on X86_64 && PROC_KCORE
1299 config ILLEGAL_POINTER_VALUE
1302 default 0xdead000000000000 if X86_64
1307 bool "Allocate 3rd-level pagetables from highmem"
1310 The VM uses one page table entry for each page of physical memory.
1311 For systems with a lot of RAM, this can be wasteful of precious
1312 low memory. Setting this option will put user-space page table
1313 entries in high memory.
1315 config X86_CHECK_BIOS_CORRUPTION
1316 bool "Check for low memory corruption"
1318 Periodically check for memory corruption in low memory, which
1319 is suspected to be caused by BIOS. Even when enabled in the
1320 configuration, it is disabled at runtime. Enable it by
1321 setting "memory_corruption_check=1" on the kernel command
1322 line. By default it scans the low 64k of memory every 60
1323 seconds; see the memory_corruption_check_size and
1324 memory_corruption_check_period parameters in
1325 Documentation/kernel-parameters.txt to adjust this.
1327 When enabled with the default parameters, this option has
1328 almost no overhead, as it reserves a relatively small amount
1329 of memory and scans it infrequently. It both detects corruption
1330 and prevents it from affecting the running system.
1332 It is, however, intended as a diagnostic tool; if repeatable
1333 BIOS-originated corruption always affects the same memory,
1334 you can use memmap= to prevent the kernel from using that
1337 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1338 bool "Set the default setting of memory_corruption_check"
1339 depends on X86_CHECK_BIOS_CORRUPTION
1342 Set whether the default state of memory_corruption_check is
1345 config X86_RESERVE_LOW
1346 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1350 Specify the amount of low memory to reserve for the BIOS.
1352 The first page contains BIOS data structures that the kernel
1353 must not use, so that page must always be reserved.
1355 By default we reserve the first 64K of physical RAM, as a
1356 number of BIOSes are known to corrupt that memory range
1357 during events such as suspend/resume or monitor cable
1358 insertion, so it must not be used by the kernel.
1360 You can set this to 4 if you are absolutely sure that you
1361 trust the BIOS to get all its memory reservations and usages
1362 right. If you know your BIOS have problems beyond the
1363 default 64K area, you can set this to 640 to avoid using the
1364 entire low memory range.
1366 If you have doubts about the BIOS (e.g. suspend/resume does
1367 not work or there's kernel crashes after certain hardware
1368 hotplug events) then you might want to enable
1369 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1370 typical corruption patterns.
1372 Leave this to the default value of 64 if you are unsure.
1374 config MATH_EMULATION
1376 prompt "Math emulation" if X86_32
1378 Linux can emulate a math coprocessor (used for floating point
1379 operations) if you don't have one. 486DX and Pentium processors have
1380 a math coprocessor built in, 486SX and 386 do not, unless you added
1381 a 487DX or 387, respectively. (The messages during boot time can
1382 give you some hints here ["man dmesg"].) Everyone needs either a
1383 coprocessor or this emulation.
1385 If you don't have a math coprocessor, you need to say Y here; if you
1386 say Y here even though you have a coprocessor, the coprocessor will
1387 be used nevertheless. (This behavior can be changed with the kernel
1388 command line option "no387", which comes handy if your coprocessor
1389 is broken. Try "man bootparam" or see the documentation of your boot
1390 loader (lilo or loadlin) about how to pass options to the kernel at
1391 boot time.) This means that it is a good idea to say Y here if you
1392 intend to use this kernel on different machines.
1394 More information about the internals of the Linux math coprocessor
1395 emulation can be found in <file:arch/x86/math-emu/README>.
1397 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1398 kernel, it won't hurt.
1402 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1404 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1405 the Memory Type Range Registers (MTRRs) may be used to control
1406 processor access to memory ranges. This is most useful if you have
1407 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1408 allows bus write transfers to be combined into a larger transfer
1409 before bursting over the PCI/AGP bus. This can increase performance
1410 of image write operations 2.5 times or more. Saying Y here creates a
1411 /proc/mtrr file which may be used to manipulate your processor's
1412 MTRRs. Typically the X server should use this.
1414 This code has a reasonably generic interface so that similar
1415 control registers on other processors can be easily supported
1418 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1419 Registers (ARRs) which provide a similar functionality to MTRRs. For
1420 these, the ARRs are used to emulate the MTRRs.
1421 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1422 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1423 write-combining. All of these processors are supported by this code
1424 and it makes sense to say Y here if you have one of them.
1426 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1427 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1428 can lead to all sorts of problems, so it's good to say Y here.
1430 You can safely say Y even if your machine doesn't have MTRRs, you'll
1431 just add about 9 KB to your kernel.
1433 See <file:Documentation/x86/mtrr.txt> for more information.
1435 config MTRR_SANITIZER
1437 prompt "MTRR cleanup support"
1440 Convert MTRR layout from continuous to discrete, so X drivers can
1441 add writeback entries.
1443 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1444 The largest mtrr entry size for a continuous block can be set with
1449 config MTRR_SANITIZER_ENABLE_DEFAULT
1450 int "MTRR cleanup enable value (0-1)"
1453 depends on MTRR_SANITIZER
1455 Enable mtrr cleanup default value
1457 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1458 int "MTRR cleanup spare reg num (0-7)"
1461 depends on MTRR_SANITIZER
1463 mtrr cleanup spare entries default, it can be changed via
1464 mtrr_spare_reg_nr=N on the kernel command line.
1468 prompt "x86 PAT support" if EXPERT
1471 Use PAT attributes to setup page level cache control.
1473 PATs are the modern equivalents of MTRRs and are much more
1474 flexible than MTRRs.
1476 Say N here if you see bootup problems (boot crash, boot hang,
1477 spontaneous reboots) or a non-working video driver.
1481 config ARCH_USES_PG_UNCACHED
1487 prompt "x86 architectural random number generator" if EXPERT
1489 Enable the x86 architectural RDRAND instruction
1490 (Intel Bull Mountain technology) to generate random numbers.
1491 If supported, this is a high bandwidth, cryptographically
1492 secure hardware random number generator.
1496 prompt "Supervisor Mode Access Prevention" if EXPERT
1498 Supervisor Mode Access Prevention (SMAP) is a security
1499 feature in newer Intel processors. There is a small
1500 performance cost if this enabled and turned on; there is
1501 also a small increase in the kernel size if this is enabled.
1506 bool "EFI runtime service support"
1509 This enables the kernel to use EFI runtime services that are
1510 available (such as the EFI variable services).
1512 This option is only useful on systems that have EFI firmware.
1513 In addition, you should use the latest ELILO loader available
1514 at <http://elilo.sourceforge.net> in order to take advantage
1515 of EFI runtime services. However, even with this option, the
1516 resultant kernel should continue to boot on existing non-EFI
1520 bool "EFI stub support"
1523 This kernel feature allows a bzImage to be loaded directly
1524 by EFI firmware without the use of a bootloader.
1526 See Documentation/x86/efi-stub.txt for more information.
1530 prompt "Enable seccomp to safely compute untrusted bytecode"
1532 This kernel feature is useful for number crunching applications
1533 that may need to compute untrusted bytecode during their
1534 execution. By using pipes or other transports made available to
1535 the process as file descriptors supporting the read/write
1536 syscalls, it's possible to isolate those applications in
1537 their own address space using seccomp. Once seccomp is
1538 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1539 and the task is only allowed to execute a few safe syscalls
1540 defined by each seccomp mode.
1542 If unsure, say Y. Only embedded should say N here.
1544 config CC_STACKPROTECTOR
1545 bool "Enable -fstack-protector buffer overflow detection"
1547 This option turns on the -fstack-protector GCC feature. This
1548 feature puts, at the beginning of functions, a canary value on
1549 the stack just before the return address, and validates
1550 the value just before actually returning. Stack based buffer
1551 overflows (that need to overwrite this return address) now also
1552 overwrite the canary, which gets detected and the attack is then
1553 neutralized via a kernel panic.
1555 This feature requires gcc version 4.2 or above, or a distribution
1556 gcc with the feature backported. Older versions are automatically
1557 detected and for those versions, this configuration option is
1558 ignored. (and a warning is printed during bootup)
1560 source kernel/Kconfig.hz
1563 bool "kexec system call"
1565 kexec is a system call that implements the ability to shutdown your
1566 current kernel, and to start another kernel. It is like a reboot
1567 but it is independent of the system firmware. And like a reboot
1568 you can start any kernel with it, not just Linux.
1570 The name comes from the similarity to the exec system call.
1572 It is an ongoing process to be certain the hardware in a machine
1573 is properly shutdown, so do not be surprised if this code does not
1574 initially work for you. It may help to enable device hotplugging
1575 support. As of this writing the exact hardware interface is
1576 strongly in flux, so no good recommendation can be made.
1579 bool "kernel crash dumps"
1580 depends on X86_64 || (X86_32 && HIGHMEM)
1582 Generate crash dump after being started by kexec.
1583 This should be normally only set in special crash dump kernels
1584 which are loaded in the main kernel with kexec-tools into
1585 a specially reserved region and then later executed after
1586 a crash by kdump/kexec. The crash dump kernel must be compiled
1587 to a memory address not used by the main kernel or BIOS using
1588 PHYSICAL_START, or it must be built as a relocatable image
1589 (CONFIG_RELOCATABLE=y).
1590 For more details see Documentation/kdump/kdump.txt
1593 bool "kexec jump (EXPERIMENTAL)"
1594 depends on EXPERIMENTAL
1595 depends on KEXEC && HIBERNATION
1597 Jump between original kernel and kexeced kernel and invoke
1598 code in physical address mode via KEXEC
1600 config PHYSICAL_START
1601 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1604 This gives the physical address where the kernel is loaded.
1606 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1607 bzImage will decompress itself to above physical address and
1608 run from there. Otherwise, bzImage will run from the address where
1609 it has been loaded by the boot loader and will ignore above physical
1612 In normal kdump cases one does not have to set/change this option
1613 as now bzImage can be compiled as a completely relocatable image
1614 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1615 address. This option is mainly useful for the folks who don't want
1616 to use a bzImage for capturing the crash dump and want to use a
1617 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1618 to be specifically compiled to run from a specific memory area
1619 (normally a reserved region) and this option comes handy.
1621 So if you are using bzImage for capturing the crash dump,
1622 leave the value here unchanged to 0x1000000 and set
1623 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1624 for capturing the crash dump change this value to start of
1625 the reserved region. In other words, it can be set based on
1626 the "X" value as specified in the "crashkernel=YM@XM"
1627 command line boot parameter passed to the panic-ed
1628 kernel. Please take a look at Documentation/kdump/kdump.txt
1629 for more details about crash dumps.
1631 Usage of bzImage for capturing the crash dump is recommended as
1632 one does not have to build two kernels. Same kernel can be used
1633 as production kernel and capture kernel. Above option should have
1634 gone away after relocatable bzImage support is introduced. But it
1635 is present because there are users out there who continue to use
1636 vmlinux for dump capture. This option should go away down the
1639 Don't change this unless you know what you are doing.
1642 bool "Build a relocatable kernel"
1645 This builds a kernel image that retains relocation information
1646 so it can be loaded someplace besides the default 1MB.
1647 The relocations tend to make the kernel binary about 10% larger,
1648 but are discarded at runtime.
1650 One use is for the kexec on panic case where the recovery kernel
1651 must live at a different physical address than the primary
1654 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1655 it has been loaded at and the compile time physical address
1656 (CONFIG_PHYSICAL_START) is ignored.
1658 # Relocation on x86-32 needs some additional build support
1659 config X86_NEED_RELOCS
1661 depends on X86_32 && RELOCATABLE
1663 config PHYSICAL_ALIGN
1664 hex "Alignment value to which kernel should be aligned" if X86_32
1666 range 0x2000 0x1000000
1668 This value puts the alignment restrictions on physical address
1669 where kernel is loaded and run from. Kernel is compiled for an
1670 address which meets above alignment restriction.
1672 If bootloader loads the kernel at a non-aligned address and
1673 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1674 address aligned to above value and run from there.
1676 If bootloader loads the kernel at a non-aligned address and
1677 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1678 load address and decompress itself to the address it has been
1679 compiled for and run from there. The address for which kernel is
1680 compiled already meets above alignment restrictions. Hence the
1681 end result is that kernel runs from a physical address meeting
1682 above alignment restrictions.
1684 Don't change this unless you know what you are doing.
1687 bool "Support for hot-pluggable CPUs"
1688 depends on SMP && HOTPLUG
1690 Say Y here to allow turning CPUs off and on. CPUs can be
1691 controlled through /sys/devices/system/cpu.
1692 ( Note: power management support will enable this option
1693 automatically on SMP systems. )
1694 Say N if you want to disable CPU hotplug.
1696 config BOOTPARAM_HOTPLUG_CPU0
1697 bool "Set default setting of cpu0_hotpluggable"
1699 depends on HOTPLUG_CPU && EXPERIMENTAL
1701 Set whether default state of cpu0_hotpluggable is on or off.
1703 Say Y here to enable CPU0 hotplug by default. If this switch
1704 is turned on, there is no need to give cpu0_hotplug kernel
1705 parameter and the CPU0 hotplug feature is enabled by default.
1707 Please note: there are two known CPU0 dependencies if you want
1708 to enable the CPU0 hotplug feature either by this switch or by
1709 cpu0_hotplug kernel parameter.
1711 First, resume from hibernate or suspend always starts from CPU0.
1712 So hibernate and suspend are prevented if CPU0 is offline.
1714 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1715 offline if any interrupt can not migrate out of CPU0. There may
1716 be other CPU0 dependencies.
1718 Please make sure the dependencies are under your control before
1719 you enable this feature.
1721 Say N if you don't want to enable CPU0 hotplug feature by default.
1722 You still can enable the CPU0 hotplug feature at boot by kernel
1723 parameter cpu0_hotplug.
1725 config DEBUG_HOTPLUG_CPU0
1727 prompt "Debug CPU0 hotplug"
1728 depends on HOTPLUG_CPU && EXPERIMENTAL
1730 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1731 soon as possible and boots up userspace with CPU0 offlined. User
1732 can online CPU0 back after boot time.
1734 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1735 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1736 compilation or giving cpu0_hotplug kernel parameter at boot.
1742 prompt "Compat VDSO support"
1743 depends on X86_32 || IA32_EMULATION
1745 Map the 32-bit VDSO to the predictable old-style address too.
1747 Say N here if you are running a sufficiently recent glibc
1748 version (2.3.3 or later), to remove the high-mapped
1749 VDSO mapping and to exclusively use the randomized VDSO.
1754 bool "Built-in kernel command line"
1756 Allow for specifying boot arguments to the kernel at
1757 build time. On some systems (e.g. embedded ones), it is
1758 necessary or convenient to provide some or all of the
1759 kernel boot arguments with the kernel itself (that is,
1760 to not rely on the boot loader to provide them.)
1762 To compile command line arguments into the kernel,
1763 set this option to 'Y', then fill in the
1764 the boot arguments in CONFIG_CMDLINE.
1766 Systems with fully functional boot loaders (i.e. non-embedded)
1767 should leave this option set to 'N'.
1770 string "Built-in kernel command string"
1771 depends on CMDLINE_BOOL
1774 Enter arguments here that should be compiled into the kernel
1775 image and used at boot time. If the boot loader provides a
1776 command line at boot time, it is appended to this string to
1777 form the full kernel command line, when the system boots.
1779 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1780 change this behavior.
1782 In most cases, the command line (whether built-in or provided
1783 by the boot loader) should specify the device for the root
1786 config CMDLINE_OVERRIDE
1787 bool "Built-in command line overrides boot loader arguments"
1788 depends on CMDLINE_BOOL
1790 Set this option to 'Y' to have the kernel ignore the boot loader
1791 command line, and use ONLY the built-in command line.
1793 This is used to work around broken boot loaders. This should
1794 be set to 'N' under normal conditions.
1798 config ARCH_ENABLE_MEMORY_HOTPLUG
1800 depends on X86_64 || (X86_32 && HIGHMEM)
1802 config ARCH_ENABLE_MEMORY_HOTREMOVE
1804 depends on MEMORY_HOTPLUG
1806 config USE_PERCPU_NUMA_NODE_ID
1810 menu "Power management and ACPI options"
1812 config ARCH_HIBERNATION_HEADER
1814 depends on X86_64 && HIBERNATION
1816 source "kernel/power/Kconfig"
1818 source "drivers/acpi/Kconfig"
1820 source "drivers/sfi/Kconfig"
1827 tristate "APM (Advanced Power Management) BIOS support"
1828 depends on X86_32 && PM_SLEEP
1830 APM is a BIOS specification for saving power using several different
1831 techniques. This is mostly useful for battery powered laptops with
1832 APM compliant BIOSes. If you say Y here, the system time will be
1833 reset after a RESUME operation, the /proc/apm device will provide
1834 battery status information, and user-space programs will receive
1835 notification of APM "events" (e.g. battery status change).
1837 If you select "Y" here, you can disable actual use of the APM
1838 BIOS by passing the "apm=off" option to the kernel at boot time.
1840 Note that the APM support is almost completely disabled for
1841 machines with more than one CPU.
1843 In order to use APM, you will need supporting software. For location
1844 and more information, read <file:Documentation/power/apm-acpi.txt>
1845 and the Battery Powered Linux mini-HOWTO, available from
1846 <http://www.tldp.org/docs.html#howto>.
1848 This driver does not spin down disk drives (see the hdparm(8)
1849 manpage ("man 8 hdparm") for that), and it doesn't turn off
1850 VESA-compliant "green" monitors.
1852 This driver does not support the TI 4000M TravelMate and the ACER
1853 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1854 desktop machines also don't have compliant BIOSes, and this driver
1855 may cause those machines to panic during the boot phase.
1857 Generally, if you don't have a battery in your machine, there isn't
1858 much point in using this driver and you should say N. If you get
1859 random kernel OOPSes or reboots that don't seem to be related to
1860 anything, try disabling/enabling this option (or disabling/enabling
1863 Some other things you should try when experiencing seemingly random,
1866 1) make sure that you have enough swap space and that it is
1868 2) pass the "no-hlt" option to the kernel
1869 3) switch on floating point emulation in the kernel and pass
1870 the "no387" option to the kernel
1871 4) pass the "floppy=nodma" option to the kernel
1872 5) pass the "mem=4M" option to the kernel (thereby disabling
1873 all but the first 4 MB of RAM)
1874 6) make sure that the CPU is not over clocked.
1875 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1876 8) disable the cache from your BIOS settings
1877 9) install a fan for the video card or exchange video RAM
1878 10) install a better fan for the CPU
1879 11) exchange RAM chips
1880 12) exchange the motherboard.
1882 To compile this driver as a module, choose M here: the
1883 module will be called apm.
1887 config APM_IGNORE_USER_SUSPEND
1888 bool "Ignore USER SUSPEND"
1890 This option will ignore USER SUSPEND requests. On machines with a
1891 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1892 series notebooks, it is necessary to say Y because of a BIOS bug.
1894 config APM_DO_ENABLE
1895 bool "Enable PM at boot time"
1897 Enable APM features at boot time. From page 36 of the APM BIOS
1898 specification: "When disabled, the APM BIOS does not automatically
1899 power manage devices, enter the Standby State, enter the Suspend
1900 State, or take power saving steps in response to CPU Idle calls."
1901 This driver will make CPU Idle calls when Linux is idle (unless this
1902 feature is turned off -- see "Do CPU IDLE calls", below). This
1903 should always save battery power, but more complicated APM features
1904 will be dependent on your BIOS implementation. You may need to turn
1905 this option off if your computer hangs at boot time when using APM
1906 support, or if it beeps continuously instead of suspending. Turn
1907 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1908 T400CDT. This is off by default since most machines do fine without
1912 bool "Make CPU Idle calls when idle"
1914 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1915 On some machines, this can activate improved power savings, such as
1916 a slowed CPU clock rate, when the machine is idle. These idle calls
1917 are made after the idle loop has run for some length of time (e.g.,
1918 333 mS). On some machines, this will cause a hang at boot time or
1919 whenever the CPU becomes idle. (On machines with more than one CPU,
1920 this option does nothing.)
1922 config APM_DISPLAY_BLANK
1923 bool "Enable console blanking using APM"
1925 Enable console blanking using the APM. Some laptops can use this to
1926 turn off the LCD backlight when the screen blanker of the Linux
1927 virtual console blanks the screen. Note that this is only used by
1928 the virtual console screen blanker, and won't turn off the backlight
1929 when using the X Window system. This also doesn't have anything to
1930 do with your VESA-compliant power-saving monitor. Further, this
1931 option doesn't work for all laptops -- it might not turn off your
1932 backlight at all, or it might print a lot of errors to the console,
1933 especially if you are using gpm.
1935 config APM_ALLOW_INTS
1936 bool "Allow interrupts during APM BIOS calls"
1938 Normally we disable external interrupts while we are making calls to
1939 the APM BIOS as a measure to lessen the effects of a badly behaving
1940 BIOS implementation. The BIOS should reenable interrupts if it
1941 needs to. Unfortunately, some BIOSes do not -- especially those in
1942 many of the newer IBM Thinkpads. If you experience hangs when you
1943 suspend, try setting this to Y. Otherwise, say N.
1947 source "drivers/cpufreq/Kconfig"
1949 source "drivers/cpuidle/Kconfig"
1951 source "drivers/idle/Kconfig"
1956 menu "Bus options (PCI etc.)"
1961 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1963 Find out whether you have a PCI motherboard. PCI is the name of a
1964 bus system, i.e. the way the CPU talks to the other stuff inside
1965 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1966 VESA. If you have PCI, say Y, otherwise N.
1969 prompt "PCI access mode"
1970 depends on X86_32 && PCI
1973 On PCI systems, the BIOS can be used to detect the PCI devices and
1974 determine their configuration. However, some old PCI motherboards
1975 have BIOS bugs and may crash if this is done. Also, some embedded
1976 PCI-based systems don't have any BIOS at all. Linux can also try to
1977 detect the PCI hardware directly without using the BIOS.
1979 With this option, you can specify how Linux should detect the
1980 PCI devices. If you choose "BIOS", the BIOS will be used,
1981 if you choose "Direct", the BIOS won't be used, and if you
1982 choose "MMConfig", then PCI Express MMCONFIG will be used.
1983 If you choose "Any", the kernel will try MMCONFIG, then the
1984 direct access method and falls back to the BIOS if that doesn't
1985 work. If unsure, go with the default, which is "Any".
1990 config PCI_GOMMCONFIG
2007 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2009 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2012 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2016 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2020 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2024 depends on PCI && XEN
2032 bool "Support mmconfig PCI config space access"
2033 depends on X86_64 && PCI && ACPI
2035 config PCI_CNB20LE_QUIRK
2036 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2037 depends on PCI && EXPERIMENTAL
2039 Read the PCI windows out of the CNB20LE host bridge. This allows
2040 PCI hotplug to work on systems with the CNB20LE chipset which do
2043 There's no public spec for this chipset, and this functionality
2044 is known to be incomplete.
2046 You should say N unless you know you need this.
2048 source "drivers/pci/pcie/Kconfig"
2050 source "drivers/pci/Kconfig"
2052 # x86_64 have no ISA slots, but can have ISA-style DMA.
2054 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2057 Enables ISA-style DMA support for devices requiring such controllers.
2065 Find out whether you have ISA slots on your motherboard. ISA is the
2066 name of a bus system, i.e. the way the CPU talks to the other stuff
2067 inside your box. Other bus systems are PCI, EISA, MicroChannel
2068 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2069 newer boards don't support it. If you have ISA, say Y, otherwise N.
2075 The Extended Industry Standard Architecture (EISA) bus was
2076 developed as an open alternative to the IBM MicroChannel bus.
2078 The EISA bus provided some of the features of the IBM MicroChannel
2079 bus while maintaining backward compatibility with cards made for
2080 the older ISA bus. The EISA bus saw limited use between 1988 and
2081 1995 when it was made obsolete by the PCI bus.
2083 Say Y here if you are building a kernel for an EISA-based machine.
2087 source "drivers/eisa/Kconfig"
2090 tristate "NatSemi SCx200 support"
2092 This provides basic support for National Semiconductor's
2093 (now AMD's) Geode processors. The driver probes for the
2094 PCI-IDs of several on-chip devices, so its a good dependency
2095 for other scx200_* drivers.
2097 If compiled as a module, the driver is named scx200.
2099 config SCx200HR_TIMER
2100 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2104 This driver provides a clocksource built upon the on-chip
2105 27MHz high-resolution timer. Its also a workaround for
2106 NSC Geode SC-1100's buggy TSC, which loses time when the
2107 processor goes idle (as is done by the scheduler). The
2108 other workaround is idle=poll boot option.
2111 bool "One Laptop Per Child support"
2118 Add support for detecting the unique features of the OLPC
2122 bool "OLPC XO-1 Power Management"
2123 depends on OLPC && MFD_CS5535 && PM_SLEEP
2126 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2129 bool "OLPC XO-1 Real Time Clock"
2130 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2132 Add support for the XO-1 real time clock, which can be used as a
2133 programmable wakeup source.
2136 bool "OLPC XO-1 SCI extras"
2137 depends on OLPC && OLPC_XO1_PM
2142 Add support for SCI-based features of the OLPC XO-1 laptop:
2143 - EC-driven system wakeups
2147 - AC adapter status updates
2148 - Battery status updates
2150 config OLPC_XO15_SCI
2151 bool "OLPC XO-1.5 SCI extras"
2152 depends on OLPC && ACPI
2155 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2156 - EC-driven system wakeups
2157 - AC adapter status updates
2158 - Battery status updates
2161 bool "PCEngines ALIX System Support (LED setup)"
2164 This option enables system support for the PCEngines ALIX.
2165 At present this just sets up LEDs for GPIO control on
2166 ALIX2/3/6 boards. However, other system specific setup should
2169 Note: You must still enable the drivers for GPIO and LED support
2170 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2172 Note: You have to set alix.force=1 for boards with Award BIOS.
2175 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2178 This option enables system support for the Soekris Engineering net5501.
2181 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2185 This option enables system support for the Traverse Technologies GEOS.
2191 depends on CPU_SUP_AMD && PCI
2193 source "drivers/pcmcia/Kconfig"
2195 source "drivers/pci/hotplug/Kconfig"
2198 bool "RapidIO support"
2202 If you say Y here, the kernel will include drivers and
2203 infrastructure code to support RapidIO interconnect devices.
2205 source "drivers/rapidio/Kconfig"
2210 menu "Executable file formats / Emulations"
2212 source "fs/Kconfig.binfmt"
2214 config IA32_EMULATION
2215 bool "IA32 Emulation"
2217 select COMPAT_BINFMT_ELF
2220 Include code to run legacy 32-bit programs under a
2221 64-bit kernel. You should likely turn this on, unless you're
2222 100% sure that you don't have any 32-bit programs left.
2225 tristate "IA32 a.out support"
2226 depends on IA32_EMULATION
2228 Support old a.out binaries in the 32bit emulation.
2231 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2232 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2234 Include code to run binaries for the x32 native 32-bit ABI
2235 for 64-bit processors. An x32 process gets access to the
2236 full 64-bit register file and wide data path while leaving
2237 pointers at 32 bits for smaller memory footprint.
2239 You will need a recent binutils (2.22 or later) with
2240 elf32_x86_64 support enabled to compile a kernel with this
2245 depends on IA32_EMULATION || X86_X32
2246 select ARCH_WANT_OLD_COMPAT_IPC
2249 config COMPAT_FOR_U64_ALIGNMENT
2252 config SYSVIPC_COMPAT
2264 config HAVE_ATOMIC_IOMAP
2268 config HAVE_TEXT_POKE_SMP
2270 select STOP_MACHINE if SMP
2272 config X86_DEV_DMA_OPS
2274 depends on X86_64 || STA2X11
2276 config X86_DMA_REMAP
2280 source "net/Kconfig"
2282 source "drivers/Kconfig"
2284 source "drivers/firmware/Kconfig"
2288 source "arch/x86/Kconfig.debug"
2290 source "security/Kconfig"
2292 source "crypto/Kconfig"
2294 source "arch/x86/kvm/Kconfig"
2296 source "lib/Kconfig"