3 bool "64-bit kernel" if ARCH = "x86"
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
25 select ARCH_SUPPORTS_NUMA_BALANCING
26 select ARCH_WANTS_PROT_NUMA_PROT_NONE
29 select HAVE_PCSPKR_PLATFORM
30 select HAVE_PERF_EVENTS
31 select HAVE_IOREMAP_PROT
34 select HAVE_MEMBLOCK_NODE_MAP
35 select ARCH_DISCARD_MEMBLOCK
36 select ARCH_WANT_OPTIONAL_GPIOLIB
37 select ARCH_WANT_FRAME_POINTERS
39 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
40 select HAVE_KRETPROBES
42 select HAVE_KPROBES_ON_FTRACE
43 select HAVE_FTRACE_MCOUNT_RECORD
44 select HAVE_FENTRY if X86_64
45 select HAVE_C_RECORDMCOUNT
46 select HAVE_DYNAMIC_FTRACE
47 select HAVE_DYNAMIC_FTRACE_WITH_REGS
48 select HAVE_FUNCTION_TRACER
49 select HAVE_FUNCTION_GRAPH_TRACER
50 select HAVE_FUNCTION_GRAPH_FP_TEST
51 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
52 select HAVE_SYSCALL_TRACEPOINTS
53 select SYSCTL_EXCEPTION_TRACE
56 select HAVE_ARCH_TRACEHOOK
57 select HAVE_GENERIC_DMA_COHERENT if X86_32
58 select HAVE_EFFICIENT_UNALIGNED_ACCESS
59 select USER_STACKTRACE_SUPPORT
60 select HAVE_REGS_AND_STACK_ACCESS_API
61 select HAVE_DMA_API_DEBUG
62 select HAVE_KERNEL_GZIP
63 select HAVE_KERNEL_BZIP2
64 select HAVE_KERNEL_LZMA
66 select HAVE_KERNEL_LZO
67 select HAVE_HW_BREAKPOINT
68 select HAVE_MIXED_BREAKPOINTS_REGS
70 select HAVE_PERF_EVENTS_NMI
72 select HAVE_PERF_USER_STACK_DUMP
73 select HAVE_DEBUG_KMEMLEAK
75 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
76 select HAVE_CMPXCHG_LOCAL
77 select HAVE_CMPXCHG_DOUBLE
78 select HAVE_ARCH_KMEMCHECK
79 select HAVE_USER_RETURN_NOTIFIER
80 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
81 select HAVE_ARCH_JUMP_LABEL
82 select HAVE_TEXT_POKE_SMP
83 select HAVE_GENERIC_HARDIRQS
84 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
86 select GENERIC_FIND_FIRST_BIT
87 select GENERIC_IRQ_PROBE
88 select GENERIC_PENDING_IRQ if SMP
89 select GENERIC_IRQ_SHOW
90 select GENERIC_CLOCKEVENTS_MIN_ADJUST
91 select IRQ_FORCED_THREADING
92 select USE_GENERIC_SMP_HELPERS if SMP
93 select HAVE_BPF_JIT if X86_64
94 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
96 select ARCH_HAVE_NMI_SAFE_CMPXCHG
98 select DCACHE_WORD_ACCESS
99 select GENERIC_SMP_IDLE_THREAD
100 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
101 select HAVE_ARCH_SECCOMP_FILTER
102 select BUILDTIME_EXTABLE_SORT
103 select GENERIC_CMOS_UPDATE
104 select CLOCKSOURCE_WATCHDOG
105 select GENERIC_CLOCKEVENTS
106 select ARCH_CLOCKSOURCE_DATA if X86_64
107 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
108 select GENERIC_TIME_VSYSCALL if X86_64
109 select KTIME_SCALAR if X86_32
110 select ALWAYS_USE_PERSISTENT_CLOCK
111 select GENERIC_STRNCPY_FROM_USER
112 select GENERIC_STRNLEN_USER
113 select HAVE_CONTEXT_TRACKING if X86_64
114 select HAVE_IRQ_TIME_ACCOUNTING
115 select MODULES_USE_ELF_REL if X86_32
116 select MODULES_USE_ELF_RELA if X86_64
117 select CLONE_BACKWARDS if X86_32
118 select GENERIC_SIGALTSTACK
119 select ARCH_USE_BUILTIN_BSWAP
121 config INSTRUCTION_DECODER
123 depends on KPROBES || PERF_EVENTS || UPROBES
127 default "elf32-i386" if X86_32
128 default "elf64-x86-64" if X86_64
130 config ARCH_DEFCONFIG
132 default "arch/x86/configs/i386_defconfig" if X86_32
133 default "arch/x86/configs/x86_64_defconfig" if X86_64
135 config LOCKDEP_SUPPORT
138 config STACKTRACE_SUPPORT
141 config HAVE_LATENCYTOP_SUPPORT
150 config NEED_DMA_MAP_STATE
152 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
154 config NEED_SG_DMA_LENGTH
157 config GENERIC_ISA_DMA
159 depends on ISA_DMA_API
164 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
166 config GENERIC_BUG_RELATIVE_POINTERS
169 config GENERIC_HWEIGHT
175 config ARCH_MAY_HAVE_PC_FDC
177 depends on ISA_DMA_API
179 config RWSEM_XCHGADD_ALGORITHM
182 config GENERIC_CALIBRATE_DELAY
185 config ARCH_HAS_CPU_RELAX
188 config ARCH_HAS_DEFAULT_IDLE
191 config ARCH_HAS_CACHE_LINE_SIZE
194 config ARCH_HAS_CPU_AUTOPROBE
197 config HAVE_SETUP_PER_CPU_AREA
200 config NEED_PER_CPU_EMBED_FIRST_CHUNK
203 config NEED_PER_CPU_PAGE_FIRST_CHUNK
206 config ARCH_HIBERNATION_POSSIBLE
209 config ARCH_SUSPEND_POSSIBLE
220 config ARCH_SUPPORTS_OPTIMIZED_INLINING
223 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
226 config HAVE_INTEL_TXT
228 depends on INTEL_IOMMU && ACPI
232 depends on X86_32 && SMP
236 depends on X86_64 && SMP
242 config X86_32_LAZY_GS
244 depends on X86_32 && !CC_STACKPROTECTOR
246 config ARCH_HWEIGHT_CFLAGS
248 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
249 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
251 config ARCH_CPU_PROBE_RELEASE
253 depends on HOTPLUG_CPU
255 config ARCH_SUPPORTS_UPROBES
258 source "init/Kconfig"
259 source "kernel/Kconfig.freezer"
261 menu "Processor type and features"
264 bool "DMA memory allocation support" if EXPERT
267 DMA memory allocation support allows devices with less than 32-bit
268 addressing to allocate within the first 16MB of address space.
269 Disable if no such devices will be used.
274 bool "Symmetric multi-processing support"
276 This enables support for systems with more than one CPU. If you have
277 a system with only one CPU, like most personal computers, say N. If
278 you have a system with more than one CPU, say Y.
280 If you say N here, the kernel will run on single and multiprocessor
281 machines, but will use only one CPU of a multiprocessor machine. If
282 you say Y here, the kernel will run on many, but not all,
283 singleprocessor machines. On a singleprocessor machine, the kernel
284 will run faster if you say N here.
286 Note that if you say Y here and choose architecture "586" or
287 "Pentium" under "Processor family", the kernel will not work on 486
288 architectures. Similarly, multiprocessor kernels for the "PPro"
289 architecture may not work on all Pentium based boards.
291 People using multiprocessor machines who say Y here should also say
292 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
293 Management" code will be disabled if you say Y here.
295 See also <file:Documentation/x86/i386/IO-APIC.txt>,
296 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
297 <http://www.tldp.org/docs.html#howto>.
299 If you don't know what to do here, say N.
302 bool "Support x2apic"
303 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
305 This enables x2apic support on CPUs that have this feature.
307 This allows 32-bit apic IDs (so it can support very large systems),
308 and accesses the local apic via MSRs not via mmio.
310 If you don't know what to do here, say N.
313 bool "Enable MPS table" if ACPI || SFI
315 depends on X86_LOCAL_APIC
317 For old smp systems that do not have proper acpi support. Newer systems
318 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
321 bool "Support for big SMP systems with more than 8 CPUs"
322 depends on X86_32 && SMP
324 This option is needed for the systems that have more than 8 CPUs
328 depends on X86_GOLDFISH
331 config X86_EXTENDED_PLATFORM
332 bool "Support for extended (non-PC) x86 platforms"
335 If you disable this option then the kernel will only support
336 standard PC platforms. (which covers the vast majority of
339 If you enable this option then you'll be able to select support
340 for the following (non-PC) 32 bit x86 platforms:
344 SGI 320/540 (Visual Workstation)
345 STA2X11-based (e.g. Northville)
346 Summit/EXA (IBM x440)
347 Unisys ES7000 IA32 series
348 Moorestown MID devices
350 If you have one of these systems, or if you want to build a
351 generic distribution kernel, say Y here - otherwise say N.
355 config X86_EXTENDED_PLATFORM
356 bool "Support for extended (non-PC) x86 platforms"
359 If you disable this option then the kernel will only support
360 standard PC platforms. (which covers the vast majority of
363 If you enable this option then you'll be able to select support
364 for the following (non-PC) 64 bit x86 platforms:
369 If you have one of these systems, or if you want to build a
370 generic distribution kernel, say Y here - otherwise say N.
372 # This is an alphabetically sorted list of 64 bit extended platforms
373 # Please maintain the alphabetic order if and when there are additions
375 bool "Numascale NumaChip"
377 depends on X86_EXTENDED_PLATFORM
380 depends on X86_X2APIC
381 depends on PCI_MMCONFIG
383 Adds support for Numascale NumaChip large-SMP systems. Needed to
384 enable more than ~168 cores.
385 If you don't have one of these, you should say N here.
389 select PARAVIRT_GUEST
391 depends on X86_64 && PCI
392 depends on X86_EXTENDED_PLATFORM
395 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
396 supposed to run on these EM64T-based machines. Only choose this option
397 if you have one of these machines.
400 bool "SGI Ultraviolet"
402 depends on X86_EXTENDED_PLATFORM
404 depends on X86_X2APIC
406 This option is needed in order to support SGI Ultraviolet systems.
407 If you don't have one of these, you should say N here.
409 # Following is an alphabetically sorted list of 32 bit extended platforms
410 # Please maintain the alphabetic order if and when there are additions
413 bool "Goldfish (Virtual Platform)"
416 Enable support for the Goldfish virtual platform used primarily
417 for Android development. Unless you are building for the Android
418 Goldfish emulator say N here.
421 bool "CE4100 TV platform"
423 depends on PCI_GODIRECT
425 depends on X86_EXTENDED_PLATFORM
426 select X86_REBOOTFIXUPS
428 select OF_EARLY_FLATTREE
431 Select for the Intel CE media processor (CE4100) SOC.
432 This option compiles in support for the CE4100 SOC for settop
433 boxes and media devices.
435 config X86_WANT_INTEL_MID
436 bool "Intel MID platform support"
438 depends on X86_EXTENDED_PLATFORM
440 Select to build a kernel capable of supporting Intel MID platform
441 systems which do not have the PCI legacy interfaces (Moorestown,
442 Medfield). If you are building for a PC class system say N here.
444 if X86_WANT_INTEL_MID
450 bool "Medfield MID platform"
453 depends on X86_IO_APIC
461 select X86_PLATFORM_DEVICES
462 select MFD_INTEL_MSIC
464 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
465 Internet Device(MID) platform.
466 Unlike standard x86 PCs, Medfield does not have many legacy devices
467 nor standard legacy replacement devices/features. e.g. Medfield does
468 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
472 config X86_INTEL_LPSS
473 bool "Intel Low Power Subsystem Support"
477 Select to build support for Intel Low Power Subsystem such as
478 found on Intel Lynxpoint PCH. Selecting this option enables
479 things like clock tree (common clock framework) which are needed
480 by the LPSS peripheral drivers.
483 bool "RDC R-321x SoC"
485 depends on X86_EXTENDED_PLATFORM
487 select X86_REBOOTFIXUPS
489 This option is needed for RDC R-321x system-on-chip, also known
491 If you don't have one of these chips, you should say N here.
493 config X86_32_NON_STANDARD
494 bool "Support non-standard 32-bit SMP architectures"
495 depends on X86_32 && SMP
496 depends on X86_EXTENDED_PLATFORM
498 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
499 STA2X11, default subarchitectures. It is intended for a generic
500 binary kernel. If you select them all, kernel will probe it
501 one by one and will fallback to default.
503 # Alphabetically sorted list of Non standard 32 bit platforms
506 bool "NUMAQ (IBM/Sequent)"
507 depends on X86_32_NON_STANDARD
512 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
513 NUMA multiquad box. This changes the way that processors are
514 bootstrapped, and uses Clustered Logical APIC addressing mode instead
515 of Flat Logical. You will need a new lynxer.elf file to flash your
518 config X86_SUPPORTS_MEMORY_FAILURE
520 # MCE code calls memory_failure():
522 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
523 depends on !X86_NUMAQ
524 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
525 depends on X86_64 || !SPARSEMEM
526 select ARCH_SUPPORTS_MEMORY_FAILURE
529 bool "SGI 320/540 (Visual Workstation)"
530 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
531 depends on X86_32_NON_STANDARD
533 The SGI Visual Workstation series is an IA32-based workstation
534 based on SGI systems chips with some legacy PC hardware attached.
536 Say Y here to create a kernel to run on the SGI 320 or 540.
538 A kernel compiled for the Visual Workstation will run on general
539 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
542 bool "STA2X11 Companion Chip Support"
543 depends on X86_32_NON_STANDARD && PCI
544 select X86_DEV_DMA_OPS
548 select ARCH_REQUIRE_GPIOLIB
551 This adds support for boards based on the STA2X11 IO-Hub,
552 a.k.a. "ConneXt". The chip is used in place of the standard
553 PC chipset, so all "standard" peripherals are missing. If this
554 option is selected the kernel will still be able to boot on
555 standard PC machines.
558 bool "Summit/EXA (IBM x440)"
559 depends on X86_32_NON_STANDARD
561 This option is needed for IBM systems that use the Summit/EXA chipset.
562 In particular, it is needed for the x440.
565 bool "Unisys ES7000 IA32 series"
566 depends on X86_32_NON_STANDARD && X86_BIGSMP
568 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
569 supposed to run on an IA32-based Unisys ES7000 system.
572 tristate "Eurobraille/Iris poweroff module"
575 The Iris machines from EuroBraille do not have APM or ACPI support
576 to shut themselves down properly. A special I/O sequence is
577 needed to do so, which is what this module does at
580 This is only for Iris machines from EuroBraille.
584 config SCHED_OMIT_FRAME_POINTER
586 prompt "Single-depth WCHAN output"
589 Calculate simpler /proc/<PID>/wchan values. If this option
590 is disabled then wchan values will recurse back to the
591 caller function. This provides more accurate wchan values,
592 at the expense of slightly more scheduling overhead.
594 If in doubt, say "Y".
596 menuconfig PARAVIRT_GUEST
597 bool "Paravirtualized guest support"
599 Say Y here to get to see options related to running Linux under
600 various hypervisors. This option alone does not add any kernel code.
602 If you say N, all options in this submenu will be skipped and disabled.
606 config PARAVIRT_TIME_ACCOUNTING
607 bool "Paravirtual steal time accounting"
611 Select this option to enable fine granularity task steal time
612 accounting. Time spent executing other tasks in parallel with
613 the current vCPU is discounted from the vCPU power. To account for
614 that, there can be a small performance impact.
616 If in doubt, say N here.
618 source "arch/x86/xen/Kconfig"
621 bool "KVM Guest support (including kvmclock)"
624 select PARAVIRT_CLOCK
625 default y if PARAVIRT_GUEST
627 This option enables various optimizations for running under the KVM
628 hypervisor. It includes a paravirtualized clock, so that instead
629 of relying on a PIT (or probably other) emulation by the
630 underlying device model, the host provides the guest with
631 timing infrastructure such as time of day, and system time
633 source "arch/x86/lguest/Kconfig"
636 bool "Enable paravirtualization code"
638 This changes the kernel so it can modify itself when it is run
639 under a hypervisor, potentially improving performance significantly
640 over full virtualization. However, when run without a hypervisor
641 the kernel is theoretically slower and slightly larger.
643 config PARAVIRT_SPINLOCKS
644 bool "Paravirtualization layer for spinlocks"
645 depends on PARAVIRT && SMP
647 Paravirtualized spinlocks allow a pvops backend to replace the
648 spinlock implementation with something virtualization-friendly
649 (for example, block the virtual CPU rather than spinning).
651 Unfortunately the downside is an up to 5% performance hit on
652 native kernels, with various workloads.
654 If you are unsure how to answer this question, answer N.
656 config PARAVIRT_CLOCK
661 config PARAVIRT_DEBUG
662 bool "paravirt-ops debugging"
663 depends on PARAVIRT && DEBUG_KERNEL
665 Enable to debug paravirt_ops internals. Specifically, BUG if
666 a paravirt_op is missing when it is called.
674 This option adds a kernel parameter 'memtest', which allows memtest
676 memtest=0, mean disabled; -- default
677 memtest=1, mean do 1 test pattern;
679 memtest=4, mean do 4 test patterns.
680 If you are unsure how to answer this question, answer N.
682 config X86_SUMMIT_NUMA
684 depends on X86_32 && NUMA && X86_32_NON_STANDARD
686 config X86_CYCLONE_TIMER
688 depends on X86_SUMMIT
690 source "arch/x86/Kconfig.cpu"
694 prompt "HPET Timer Support" if X86_32
696 Use the IA-PC HPET (High Precision Event Timer) to manage
697 time in preference to the PIT and RTC, if a HPET is
699 HPET is the next generation timer replacing legacy 8254s.
700 The HPET provides a stable time base on SMP
701 systems, unlike the TSC, but it is more expensive to access,
702 as it is off-chip. You can find the HPET spec at
703 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
705 You can safely choose Y here. However, HPET will only be
706 activated if the platform and the BIOS support this feature.
707 Otherwise the 8254 will be used for timing services.
709 Choose N to continue using the legacy 8254 timer.
711 config HPET_EMULATE_RTC
713 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
716 def_bool y if X86_INTEL_MID
717 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
719 depends on X86_INTEL_MID && SFI
721 APB timer is the replacement for 8254, HPET on X86 MID platforms.
722 The APBT provides a stable time base on SMP
723 systems, unlike the TSC, but it is more expensive to access,
724 as it is off-chip. APB timers are always running regardless of CPU
725 C states, they are used as per CPU clockevent device when possible.
727 # Mark as expert because too many people got it wrong.
728 # The code disables itself when not needed.
731 bool "Enable DMI scanning" if EXPERT
733 Enabled scanning of DMI to identify machine quirks. Say Y
734 here unless you have verified that your setup is not
735 affected by entries in the DMI blacklist. Required by PNP
739 bool "GART IOMMU support" if EXPERT
742 depends on X86_64 && PCI && AMD_NB
744 Support for full DMA access of devices with 32bit memory access only
745 on systems with more than 3GB. This is usually needed for USB,
746 sound, many IDE/SATA chipsets and some other devices.
747 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
748 based hardware IOMMU and a software bounce buffer based IOMMU used
749 on Intel systems and as fallback.
750 The code is only active when needed (enough memory and limited
751 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
755 bool "IBM Calgary IOMMU support"
757 depends on X86_64 && PCI
759 Support for hardware IOMMUs in IBM's xSeries x366 and x460
760 systems. Needed to run systems with more than 3GB of memory
761 properly with 32-bit PCI devices that do not support DAC
762 (Double Address Cycle). Calgary also supports bus level
763 isolation, where all DMAs pass through the IOMMU. This
764 prevents them from going anywhere except their intended
765 destination. This catches hard-to-find kernel bugs and
766 mis-behaving drivers and devices that do not use the DMA-API
767 properly to set up their DMA buffers. The IOMMU can be
768 turned off at boot time with the iommu=off parameter.
769 Normally the kernel will make the right choice by itself.
772 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
774 prompt "Should Calgary be enabled by default?"
775 depends on CALGARY_IOMMU
777 Should Calgary be enabled by default? if you choose 'y', Calgary
778 will be used (if it exists). If you choose 'n', Calgary will not be
779 used even if it exists. If you choose 'n' and would like to use
780 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
783 # need this always selected by IOMMU for the VIA workaround
787 Support for software bounce buffers used on x86-64 systems
788 which don't have a hardware IOMMU. Using this PCI devices
789 which can only access 32-bits of memory can be used on systems
790 with more than 3 GB of memory.
795 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
798 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
799 depends on X86_64 && SMP && DEBUG_KERNEL
800 select CPUMASK_OFFSTACK
802 Enable maximum number of CPUS and NUMA Nodes for this architecture.
806 int "Maximum number of CPUs" if SMP && !MAXSMP
807 range 2 8 if SMP && X86_32 && !X86_BIGSMP
808 range 2 512 if SMP && !MAXSMP
810 default "4096" if MAXSMP
811 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
814 This allows you to specify the maximum number of CPUs which this
815 kernel will support. The maximum supported value is 512 and the
816 minimum value which makes sense is 2.
818 This is purely to save memory - each supported CPU adds
819 approximately eight kilobytes to the kernel image.
822 bool "SMT (Hyperthreading) scheduler support"
825 SMT scheduler support improves the CPU scheduler's decision making
826 when dealing with Intel Pentium 4 chips with HyperThreading at a
827 cost of slightly increased overhead in some places. If unsure say
832 prompt "Multi-core scheduler support"
835 Multi-core scheduler support improves the CPU scheduler's decision
836 making when dealing with multi-core CPU chips at a cost of slightly
837 increased overhead in some places. If unsure say N here.
839 source "kernel/Kconfig.preempt"
842 bool "Local APIC support on uniprocessors"
843 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
845 A local APIC (Advanced Programmable Interrupt Controller) is an
846 integrated interrupt controller in the CPU. If you have a single-CPU
847 system which has a processor with a local APIC, you can say Y here to
848 enable and use it. If you say Y here even though your machine doesn't
849 have a local APIC, then the kernel will still run with no slowdown at
850 all. The local APIC supports CPU-generated self-interrupts (timer,
851 performance counters), and the NMI watchdog which detects hard
855 bool "IO-APIC support on uniprocessors"
856 depends on X86_UP_APIC
858 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
859 SMP-capable replacement for PC-style interrupt controllers. Most
860 SMP systems and many recent uniprocessor systems have one.
862 If you have a single-CPU system with an IO-APIC, you can say Y here
863 to use it. If you say Y here even though your machine doesn't have
864 an IO-APIC, then the kernel will still run with no slowdown at all.
866 config X86_LOCAL_APIC
868 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
872 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
874 config X86_VISWS_APIC
876 depends on X86_32 && X86_VISWS
878 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
879 bool "Reroute for broken boot IRQs"
880 depends on X86_IO_APIC
882 This option enables a workaround that fixes a source of
883 spurious interrupts. This is recommended when threaded
884 interrupt handling is used on systems where the generation of
885 superfluous "boot interrupts" cannot be disabled.
887 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
888 entry in the chipset's IO-APIC is masked (as, e.g. the RT
889 kernel does during interrupt handling). On chipsets where this
890 boot IRQ generation cannot be disabled, this workaround keeps
891 the original IRQ line masked so that only the equivalent "boot
892 IRQ" is delivered to the CPUs. The workaround also tells the
893 kernel to set up the IRQ handler on the boot IRQ line. In this
894 way only one interrupt is delivered to the kernel. Otherwise
895 the spurious second interrupt may cause the kernel to bring
896 down (vital) interrupt lines.
898 Only affects "broken" chipsets. Interrupt sharing may be
899 increased on these systems.
902 bool "Machine Check / overheating reporting"
905 Machine Check support allows the processor to notify the
906 kernel if it detects a problem (e.g. overheating, data corruption).
907 The action the kernel takes depends on the severity of the problem,
908 ranging from warning messages to halting the machine.
912 prompt "Intel MCE features"
913 depends on X86_MCE && X86_LOCAL_APIC
915 Additional support for intel specific MCE features such as
920 prompt "AMD MCE features"
921 depends on X86_MCE && X86_LOCAL_APIC
923 Additional support for AMD specific MCE features such as
924 the DRAM Error Threshold.
926 config X86_ANCIENT_MCE
927 bool "Support for old Pentium 5 / WinChip machine checks"
928 depends on X86_32 && X86_MCE
930 Include support for machine check handling on old Pentium 5 or WinChip
931 systems. These typically need to be enabled explicitely on the command
934 config X86_MCE_THRESHOLD
935 depends on X86_MCE_AMD || X86_MCE_INTEL
938 config X86_MCE_INJECT
940 tristate "Machine check injector support"
942 Provide support for injecting machine checks for testing purposes.
943 If you don't know what a machine check is and you don't do kernel
944 QA it is safe to say n.
946 config X86_THERMAL_VECTOR
948 depends on X86_MCE_INTEL
951 bool "Enable VM86 support" if EXPERT
955 This option is required by programs like DOSEMU to run 16-bit legacy
956 code on X86 processors. It also may be needed by software like
957 XFree86 to initialize some video cards via BIOS. Disabling this
958 option saves about 6k.
961 tristate "Toshiba Laptop support"
964 This adds a driver to safely access the System Management Mode of
965 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
966 not work on models with a Phoenix BIOS. The System Management Mode
967 is used to set the BIOS and power saving options on Toshiba portables.
969 For information on utilities to make use of this driver see the
970 Toshiba Linux utilities web site at:
971 <http://www.buzzard.org.uk/toshiba/>.
973 Say Y if you intend to run this kernel on a Toshiba portable.
977 tristate "Dell laptop support"
980 This adds a driver to safely access the System Management Mode
981 of the CPU on the Dell Inspiron 8000. The System Management Mode
982 is used to read cpu temperature and cooling fan status and to
983 control the fans on the I8K portables.
985 This driver has been tested only on the Inspiron 8000 but it may
986 also work with other Dell laptops. You can force loading on other
987 models by passing the parameter `force=1' to the module. Use at
990 For information on utilities to make use of this driver see the
991 I8K Linux utilities web site at:
992 <http://people.debian.org/~dz/i8k/>
994 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
997 config X86_REBOOTFIXUPS
998 bool "Enable X86 board specific fixups for reboot"
1001 This enables chipset and/or board specific fixups to be done
1002 in order to get reboot to work correctly. This is only needed on
1003 some combinations of hardware and BIOS. The symptom, for which
1004 this config is intended, is when reboot ends with a stalled/hung
1007 Currently, the only fixup is for the Geode machines using
1008 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1010 Say Y if you want to enable the fixup. Currently, it's safe to
1011 enable this option even if you don't need it.
1015 tristate "CPU microcode loading support"
1019 If you say Y here, you will be able to update the microcode on
1020 certain Intel and AMD processors. The Intel support is for the
1021 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1022 Xeon etc. The AMD support is for families 0x10 and later. You will
1023 obviously need the actual microcode binary data itself which is not
1024 shipped with the Linux kernel.
1026 This option selects the general module only, you need to select
1027 at least one vendor specific module as well.
1029 To compile this driver as a module, choose M here: the module
1030 will be called microcode.
1032 config MICROCODE_INTEL
1033 bool "Intel microcode loading support"
1034 depends on MICROCODE
1038 This options enables microcode patch loading support for Intel
1041 For latest news and information on obtaining all the required
1042 Intel ingredients for this driver, check:
1043 <http://www.urbanmyth.org/microcode/>.
1045 config MICROCODE_AMD
1046 bool "AMD microcode loading support"
1047 depends on MICROCODE
1050 If you select this option, microcode patch loading support for AMD
1051 processors will be enabled.
1053 config MICROCODE_OLD_INTERFACE
1055 depends on MICROCODE
1058 tristate "/dev/cpu/*/msr - Model-specific register support"
1060 This device gives privileged processes access to the x86
1061 Model-Specific Registers (MSRs). It is a character device with
1062 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1063 MSR accesses are directed to a specific CPU on multi-processor
1067 tristate "/dev/cpu/*/cpuid - CPU information support"
1069 This device gives processes access to the x86 CPUID instruction to
1070 be executed on a specific processor. It is a character device
1071 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1075 prompt "High Memory Support"
1076 default HIGHMEM64G if X86_NUMAQ
1082 depends on !X86_NUMAQ
1084 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1085 However, the address space of 32-bit x86 processors is only 4
1086 Gigabytes large. That means that, if you have a large amount of
1087 physical memory, not all of it can be "permanently mapped" by the
1088 kernel. The physical memory that's not permanently mapped is called
1091 If you are compiling a kernel which will never run on a machine with
1092 more than 1 Gigabyte total physical RAM, answer "off" here (default
1093 choice and suitable for most users). This will result in a "3GB/1GB"
1094 split: 3GB are mapped so that each process sees a 3GB virtual memory
1095 space and the remaining part of the 4GB virtual memory space is used
1096 by the kernel to permanently map as much physical memory as
1099 If the machine has between 1 and 4 Gigabytes physical RAM, then
1102 If more than 4 Gigabytes is used then answer "64GB" here. This
1103 selection turns Intel PAE (Physical Address Extension) mode on.
1104 PAE implements 3-level paging on IA32 processors. PAE is fully
1105 supported by Linux, PAE mode is implemented on all recent Intel
1106 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1107 then the kernel will not boot on CPUs that don't support PAE!
1109 The actual amount of total physical memory will either be
1110 auto detected or can be forced by using a kernel command line option
1111 such as "mem=256M". (Try "man bootparam" or see the documentation of
1112 your boot loader (lilo or loadlin) about how to pass options to the
1113 kernel at boot time.)
1115 If unsure, say "off".
1119 depends on !X86_NUMAQ
1121 Select this if you have a 32-bit processor and between 1 and 4
1122 gigabytes of physical RAM.
1129 Select this if you have a 32-bit processor and more than 4
1130 gigabytes of physical RAM.
1135 prompt "Memory split" if EXPERT
1139 Select the desired split between kernel and user memory.
1141 If the address range available to the kernel is less than the
1142 physical memory installed, the remaining memory will be available
1143 as "high memory". Accessing high memory is a little more costly
1144 than low memory, as it needs to be mapped into the kernel first.
1145 Note that increasing the kernel address space limits the range
1146 available to user programs, making the address space there
1147 tighter. Selecting anything other than the default 3G/1G split
1148 will also likely make your kernel incompatible with binary-only
1151 If you are not absolutely sure what you are doing, leave this
1155 bool "3G/1G user/kernel split"
1156 config VMSPLIT_3G_OPT
1158 bool "3G/1G user/kernel split (for full 1G low memory)"
1160 bool "2G/2G user/kernel split"
1161 config VMSPLIT_2G_OPT
1163 bool "2G/2G user/kernel split (for full 2G low memory)"
1165 bool "1G/3G user/kernel split"
1170 default 0xB0000000 if VMSPLIT_3G_OPT
1171 default 0x80000000 if VMSPLIT_2G
1172 default 0x78000000 if VMSPLIT_2G_OPT
1173 default 0x40000000 if VMSPLIT_1G
1179 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1182 bool "PAE (Physical Address Extension) Support"
1183 depends on X86_32 && !HIGHMEM4G
1185 PAE is required for NX support, and furthermore enables
1186 larger swapspace support for non-overcommit purposes. It
1187 has the cost of more pagetable lookup overhead, and also
1188 consumes more pagetable space per process.
1190 config ARCH_PHYS_ADDR_T_64BIT
1192 depends on X86_64 || X86_PAE
1194 config ARCH_DMA_ADDR_T_64BIT
1196 depends on X86_64 || HIGHMEM64G
1198 config DIRECT_GBPAGES
1199 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1203 Allow the kernel linear mapping to use 1GB pages on CPUs that
1204 support it. This can improve the kernel's performance a tiny bit by
1205 reducing TLB pressure. If in doubt, say "Y".
1207 # Common NUMA Features
1209 bool "Numa Memory Allocation and Scheduler Support"
1211 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1212 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1214 Enable NUMA (Non Uniform Memory Access) support.
1216 The kernel will try to allocate memory used by a CPU on the
1217 local memory controller of the CPU and add some more
1218 NUMA awareness to the kernel.
1220 For 64-bit this is recommended if the system is Intel Core i7
1221 (or later), AMD Opteron, or EM64T NUMA.
1223 For 32-bit this is only needed on (rare) 32-bit-only platforms
1224 that support NUMA topologies, such as NUMAQ / Summit, or if you
1225 boot a 32-bit kernel on a 64-bit NUMA platform.
1227 Otherwise, you should say N.
1229 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1230 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1234 prompt "Old style AMD Opteron NUMA detection"
1235 depends on X86_64 && NUMA && PCI
1237 Enable AMD NUMA node topology detection. You should say Y here if
1238 you have a multi processor AMD system. This uses an old method to
1239 read the NUMA configuration directly from the builtin Northbridge
1240 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1241 which also takes priority if both are compiled in.
1243 config X86_64_ACPI_NUMA
1245 prompt "ACPI NUMA detection"
1246 depends on X86_64 && NUMA && ACPI && PCI
1249 Enable ACPI SRAT based node topology detection.
1251 # Some NUMA nodes have memory ranges that span
1252 # other nodes. Even though a pfn is valid and
1253 # between a node's start and end pfns, it may not
1254 # reside on that node. See memmap_init_zone()
1256 config NODES_SPAN_OTHER_NODES
1258 depends on X86_64_ACPI_NUMA
1261 bool "NUMA emulation"
1264 Enable NUMA emulation. A flat machine will be split
1265 into virtual nodes when booted with "numa=fake=N", where N is the
1266 number of nodes. This is only useful for debugging.
1269 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1271 default "10" if MAXSMP
1272 default "6" if X86_64
1273 default "4" if X86_NUMAQ
1275 depends on NEED_MULTIPLE_NODES
1277 Specify the maximum number of NUMA Nodes available on the target
1278 system. Increases memory reserved to accommodate various tables.
1280 config ARCH_HAVE_MEMORY_PRESENT
1282 depends on X86_32 && DISCONTIGMEM
1284 config NEED_NODE_MEMMAP_SIZE
1286 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1288 config ARCH_FLATMEM_ENABLE
1290 depends on X86_32 && !NUMA
1292 config ARCH_DISCONTIGMEM_ENABLE
1294 depends on NUMA && X86_32
1296 config ARCH_DISCONTIGMEM_DEFAULT
1298 depends on NUMA && X86_32
1300 config ARCH_SPARSEMEM_ENABLE
1302 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1303 select SPARSEMEM_STATIC if X86_32
1304 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1306 config ARCH_SPARSEMEM_DEFAULT
1310 config ARCH_SELECT_MEMORY_MODEL
1312 depends on ARCH_SPARSEMEM_ENABLE
1314 config ARCH_MEMORY_PROBE
1316 depends on X86_64 && MEMORY_HOTPLUG
1318 config ARCH_PROC_KCORE_TEXT
1320 depends on X86_64 && PROC_KCORE
1322 config ILLEGAL_POINTER_VALUE
1325 default 0xdead000000000000 if X86_64
1330 bool "Allocate 3rd-level pagetables from highmem"
1333 The VM uses one page table entry for each page of physical memory.
1334 For systems with a lot of RAM, this can be wasteful of precious
1335 low memory. Setting this option will put user-space page table
1336 entries in high memory.
1338 config X86_CHECK_BIOS_CORRUPTION
1339 bool "Check for low memory corruption"
1341 Periodically check for memory corruption in low memory, which
1342 is suspected to be caused by BIOS. Even when enabled in the
1343 configuration, it is disabled at runtime. Enable it by
1344 setting "memory_corruption_check=1" on the kernel command
1345 line. By default it scans the low 64k of memory every 60
1346 seconds; see the memory_corruption_check_size and
1347 memory_corruption_check_period parameters in
1348 Documentation/kernel-parameters.txt to adjust this.
1350 When enabled with the default parameters, this option has
1351 almost no overhead, as it reserves a relatively small amount
1352 of memory and scans it infrequently. It both detects corruption
1353 and prevents it from affecting the running system.
1355 It is, however, intended as a diagnostic tool; if repeatable
1356 BIOS-originated corruption always affects the same memory,
1357 you can use memmap= to prevent the kernel from using that
1360 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1361 bool "Set the default setting of memory_corruption_check"
1362 depends on X86_CHECK_BIOS_CORRUPTION
1365 Set whether the default state of memory_corruption_check is
1368 config X86_RESERVE_LOW
1369 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1373 Specify the amount of low memory to reserve for the BIOS.
1375 The first page contains BIOS data structures that the kernel
1376 must not use, so that page must always be reserved.
1378 By default we reserve the first 64K of physical RAM, as a
1379 number of BIOSes are known to corrupt that memory range
1380 during events such as suspend/resume or monitor cable
1381 insertion, so it must not be used by the kernel.
1383 You can set this to 4 if you are absolutely sure that you
1384 trust the BIOS to get all its memory reservations and usages
1385 right. If you know your BIOS have problems beyond the
1386 default 64K area, you can set this to 640 to avoid using the
1387 entire low memory range.
1389 If you have doubts about the BIOS (e.g. suspend/resume does
1390 not work or there's kernel crashes after certain hardware
1391 hotplug events) then you might want to enable
1392 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1393 typical corruption patterns.
1395 Leave this to the default value of 64 if you are unsure.
1397 config MATH_EMULATION
1399 prompt "Math emulation" if X86_32
1401 Linux can emulate a math coprocessor (used for floating point
1402 operations) if you don't have one. 486DX and Pentium processors have
1403 a math coprocessor built in, 486SX and 386 do not, unless you added
1404 a 487DX or 387, respectively. (The messages during boot time can
1405 give you some hints here ["man dmesg"].) Everyone needs either a
1406 coprocessor or this emulation.
1408 If you don't have a math coprocessor, you need to say Y here; if you
1409 say Y here even though you have a coprocessor, the coprocessor will
1410 be used nevertheless. (This behavior can be changed with the kernel
1411 command line option "no387", which comes handy if your coprocessor
1412 is broken. Try "man bootparam" or see the documentation of your boot
1413 loader (lilo or loadlin) about how to pass options to the kernel at
1414 boot time.) This means that it is a good idea to say Y here if you
1415 intend to use this kernel on different machines.
1417 More information about the internals of the Linux math coprocessor
1418 emulation can be found in <file:arch/x86/math-emu/README>.
1420 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1421 kernel, it won't hurt.
1425 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1427 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1428 the Memory Type Range Registers (MTRRs) may be used to control
1429 processor access to memory ranges. This is most useful if you have
1430 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1431 allows bus write transfers to be combined into a larger transfer
1432 before bursting over the PCI/AGP bus. This can increase performance
1433 of image write operations 2.5 times or more. Saying Y here creates a
1434 /proc/mtrr file which may be used to manipulate your processor's
1435 MTRRs. Typically the X server should use this.
1437 This code has a reasonably generic interface so that similar
1438 control registers on other processors can be easily supported
1441 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1442 Registers (ARRs) which provide a similar functionality to MTRRs. For
1443 these, the ARRs are used to emulate the MTRRs.
1444 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1445 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1446 write-combining. All of these processors are supported by this code
1447 and it makes sense to say Y here if you have one of them.
1449 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1450 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1451 can lead to all sorts of problems, so it's good to say Y here.
1453 You can safely say Y even if your machine doesn't have MTRRs, you'll
1454 just add about 9 KB to your kernel.
1456 See <file:Documentation/x86/mtrr.txt> for more information.
1458 config MTRR_SANITIZER
1460 prompt "MTRR cleanup support"
1463 Convert MTRR layout from continuous to discrete, so X drivers can
1464 add writeback entries.
1466 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1467 The largest mtrr entry size for a continuous block can be set with
1472 config MTRR_SANITIZER_ENABLE_DEFAULT
1473 int "MTRR cleanup enable value (0-1)"
1476 depends on MTRR_SANITIZER
1478 Enable mtrr cleanup default value
1480 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1481 int "MTRR cleanup spare reg num (0-7)"
1484 depends on MTRR_SANITIZER
1486 mtrr cleanup spare entries default, it can be changed via
1487 mtrr_spare_reg_nr=N on the kernel command line.
1491 prompt "x86 PAT support" if EXPERT
1494 Use PAT attributes to setup page level cache control.
1496 PATs are the modern equivalents of MTRRs and are much more
1497 flexible than MTRRs.
1499 Say N here if you see bootup problems (boot crash, boot hang,
1500 spontaneous reboots) or a non-working video driver.
1504 config ARCH_USES_PG_UNCACHED
1510 prompt "x86 architectural random number generator" if EXPERT
1512 Enable the x86 architectural RDRAND instruction
1513 (Intel Bull Mountain technology) to generate random numbers.
1514 If supported, this is a high bandwidth, cryptographically
1515 secure hardware random number generator.
1519 prompt "Supervisor Mode Access Prevention" if EXPERT
1521 Supervisor Mode Access Prevention (SMAP) is a security
1522 feature in newer Intel processors. There is a small
1523 performance cost if this enabled and turned on; there is
1524 also a small increase in the kernel size if this is enabled.
1529 bool "EFI runtime service support"
1532 This enables the kernel to use EFI runtime services that are
1533 available (such as the EFI variable services).
1535 This option is only useful on systems that have EFI firmware.
1536 In addition, you should use the latest ELILO loader available
1537 at <http://elilo.sourceforge.net> in order to take advantage
1538 of EFI runtime services. However, even with this option, the
1539 resultant kernel should continue to boot on existing non-EFI
1543 bool "EFI stub support"
1546 This kernel feature allows a bzImage to be loaded directly
1547 by EFI firmware without the use of a bootloader.
1549 See Documentation/x86/efi-stub.txt for more information.
1553 prompt "Enable seccomp to safely compute untrusted bytecode"
1555 This kernel feature is useful for number crunching applications
1556 that may need to compute untrusted bytecode during their
1557 execution. By using pipes or other transports made available to
1558 the process as file descriptors supporting the read/write
1559 syscalls, it's possible to isolate those applications in
1560 their own address space using seccomp. Once seccomp is
1561 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1562 and the task is only allowed to execute a few safe syscalls
1563 defined by each seccomp mode.
1565 If unsure, say Y. Only embedded should say N here.
1567 config CC_STACKPROTECTOR
1568 bool "Enable -fstack-protector buffer overflow detection"
1570 This option turns on the -fstack-protector GCC feature. This
1571 feature puts, at the beginning of functions, a canary value on
1572 the stack just before the return address, and validates
1573 the value just before actually returning. Stack based buffer
1574 overflows (that need to overwrite this return address) now also
1575 overwrite the canary, which gets detected and the attack is then
1576 neutralized via a kernel panic.
1578 This feature requires gcc version 4.2 or above, or a distribution
1579 gcc with the feature backported. Older versions are automatically
1580 detected and for those versions, this configuration option is
1581 ignored. (and a warning is printed during bootup)
1583 source kernel/Kconfig.hz
1586 bool "kexec system call"
1588 kexec is a system call that implements the ability to shutdown your
1589 current kernel, and to start another kernel. It is like a reboot
1590 but it is independent of the system firmware. And like a reboot
1591 you can start any kernel with it, not just Linux.
1593 The name comes from the similarity to the exec system call.
1595 It is an ongoing process to be certain the hardware in a machine
1596 is properly shutdown, so do not be surprised if this code does not
1597 initially work for you. It may help to enable device hotplugging
1598 support. As of this writing the exact hardware interface is
1599 strongly in flux, so no good recommendation can be made.
1602 bool "kernel crash dumps"
1603 depends on X86_64 || (X86_32 && HIGHMEM)
1605 Generate crash dump after being started by kexec.
1606 This should be normally only set in special crash dump kernels
1607 which are loaded in the main kernel with kexec-tools into
1608 a specially reserved region and then later executed after
1609 a crash by kdump/kexec. The crash dump kernel must be compiled
1610 to a memory address not used by the main kernel or BIOS using
1611 PHYSICAL_START, or it must be built as a relocatable image
1612 (CONFIG_RELOCATABLE=y).
1613 For more details see Documentation/kdump/kdump.txt
1617 depends on KEXEC && HIBERNATION
1619 Jump between original kernel and kexeced kernel and invoke
1620 code in physical address mode via KEXEC
1622 config PHYSICAL_START
1623 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1626 This gives the physical address where the kernel is loaded.
1628 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1629 bzImage will decompress itself to above physical address and
1630 run from there. Otherwise, bzImage will run from the address where
1631 it has been loaded by the boot loader and will ignore above physical
1634 In normal kdump cases one does not have to set/change this option
1635 as now bzImage can be compiled as a completely relocatable image
1636 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1637 address. This option is mainly useful for the folks who don't want
1638 to use a bzImage for capturing the crash dump and want to use a
1639 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1640 to be specifically compiled to run from a specific memory area
1641 (normally a reserved region) and this option comes handy.
1643 So if you are using bzImage for capturing the crash dump,
1644 leave the value here unchanged to 0x1000000 and set
1645 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1646 for capturing the crash dump change this value to start of
1647 the reserved region. In other words, it can be set based on
1648 the "X" value as specified in the "crashkernel=YM@XM"
1649 command line boot parameter passed to the panic-ed
1650 kernel. Please take a look at Documentation/kdump/kdump.txt
1651 for more details about crash dumps.
1653 Usage of bzImage for capturing the crash dump is recommended as
1654 one does not have to build two kernels. Same kernel can be used
1655 as production kernel and capture kernel. Above option should have
1656 gone away after relocatable bzImage support is introduced. But it
1657 is present because there are users out there who continue to use
1658 vmlinux for dump capture. This option should go away down the
1661 Don't change this unless you know what you are doing.
1664 bool "Build a relocatable kernel"
1667 This builds a kernel image that retains relocation information
1668 so it can be loaded someplace besides the default 1MB.
1669 The relocations tend to make the kernel binary about 10% larger,
1670 but are discarded at runtime.
1672 One use is for the kexec on panic case where the recovery kernel
1673 must live at a different physical address than the primary
1676 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1677 it has been loaded at and the compile time physical address
1678 (CONFIG_PHYSICAL_START) is ignored.
1680 # Relocation on x86-32 needs some additional build support
1681 config X86_NEED_RELOCS
1683 depends on X86_32 && RELOCATABLE
1685 config PHYSICAL_ALIGN
1686 hex "Alignment value to which kernel should be aligned" if X86_32
1688 range 0x2000 0x1000000
1690 This value puts the alignment restrictions on physical address
1691 where kernel is loaded and run from. Kernel is compiled for an
1692 address which meets above alignment restriction.
1694 If bootloader loads the kernel at a non-aligned address and
1695 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1696 address aligned to above value and run from there.
1698 If bootloader loads the kernel at a non-aligned address and
1699 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1700 load address and decompress itself to the address it has been
1701 compiled for and run from there. The address for which kernel is
1702 compiled already meets above alignment restrictions. Hence the
1703 end result is that kernel runs from a physical address meeting
1704 above alignment restrictions.
1706 Don't change this unless you know what you are doing.
1709 bool "Support for hot-pluggable CPUs"
1710 depends on SMP && HOTPLUG
1712 Say Y here to allow turning CPUs off and on. CPUs can be
1713 controlled through /sys/devices/system/cpu.
1714 ( Note: power management support will enable this option
1715 automatically on SMP systems. )
1716 Say N if you want to disable CPU hotplug.
1718 config BOOTPARAM_HOTPLUG_CPU0
1719 bool "Set default setting of cpu0_hotpluggable"
1721 depends on HOTPLUG_CPU
1723 Set whether default state of cpu0_hotpluggable is on or off.
1725 Say Y here to enable CPU0 hotplug by default. If this switch
1726 is turned on, there is no need to give cpu0_hotplug kernel
1727 parameter and the CPU0 hotplug feature is enabled by default.
1729 Please note: there are two known CPU0 dependencies if you want
1730 to enable the CPU0 hotplug feature either by this switch or by
1731 cpu0_hotplug kernel parameter.
1733 First, resume from hibernate or suspend always starts from CPU0.
1734 So hibernate and suspend are prevented if CPU0 is offline.
1736 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1737 offline if any interrupt can not migrate out of CPU0. There may
1738 be other CPU0 dependencies.
1740 Please make sure the dependencies are under your control before
1741 you enable this feature.
1743 Say N if you don't want to enable CPU0 hotplug feature by default.
1744 You still can enable the CPU0 hotplug feature at boot by kernel
1745 parameter cpu0_hotplug.
1747 config DEBUG_HOTPLUG_CPU0
1749 prompt "Debug CPU0 hotplug"
1750 depends on HOTPLUG_CPU
1752 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1753 soon as possible and boots up userspace with CPU0 offlined. User
1754 can online CPU0 back after boot time.
1756 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1757 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1758 compilation or giving cpu0_hotplug kernel parameter at boot.
1764 prompt "Compat VDSO support"
1765 depends on X86_32 || IA32_EMULATION
1767 Map the 32-bit VDSO to the predictable old-style address too.
1769 Say N here if you are running a sufficiently recent glibc
1770 version (2.3.3 or later), to remove the high-mapped
1771 VDSO mapping and to exclusively use the randomized VDSO.
1776 bool "Built-in kernel command line"
1778 Allow for specifying boot arguments to the kernel at
1779 build time. On some systems (e.g. embedded ones), it is
1780 necessary or convenient to provide some or all of the
1781 kernel boot arguments with the kernel itself (that is,
1782 to not rely on the boot loader to provide them.)
1784 To compile command line arguments into the kernel,
1785 set this option to 'Y', then fill in the
1786 the boot arguments in CONFIG_CMDLINE.
1788 Systems with fully functional boot loaders (i.e. non-embedded)
1789 should leave this option set to 'N'.
1792 string "Built-in kernel command string"
1793 depends on CMDLINE_BOOL
1796 Enter arguments here that should be compiled into the kernel
1797 image and used at boot time. If the boot loader provides a
1798 command line at boot time, it is appended to this string to
1799 form the full kernel command line, when the system boots.
1801 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1802 change this behavior.
1804 In most cases, the command line (whether built-in or provided
1805 by the boot loader) should specify the device for the root
1808 config CMDLINE_OVERRIDE
1809 bool "Built-in command line overrides boot loader arguments"
1810 depends on CMDLINE_BOOL
1812 Set this option to 'Y' to have the kernel ignore the boot loader
1813 command line, and use ONLY the built-in command line.
1815 This is used to work around broken boot loaders. This should
1816 be set to 'N' under normal conditions.
1820 config ARCH_ENABLE_MEMORY_HOTPLUG
1822 depends on X86_64 || (X86_32 && HIGHMEM)
1824 config ARCH_ENABLE_MEMORY_HOTREMOVE
1826 depends on MEMORY_HOTPLUG
1828 config USE_PERCPU_NUMA_NODE_ID
1832 menu "Power management and ACPI options"
1834 config ARCH_HIBERNATION_HEADER
1836 depends on X86_64 && HIBERNATION
1838 source "kernel/power/Kconfig"
1840 source "drivers/acpi/Kconfig"
1842 source "drivers/sfi/Kconfig"
1849 tristate "APM (Advanced Power Management) BIOS support"
1850 depends on X86_32 && PM_SLEEP
1852 APM is a BIOS specification for saving power using several different
1853 techniques. This is mostly useful for battery powered laptops with
1854 APM compliant BIOSes. If you say Y here, the system time will be
1855 reset after a RESUME operation, the /proc/apm device will provide
1856 battery status information, and user-space programs will receive
1857 notification of APM "events" (e.g. battery status change).
1859 If you select "Y" here, you can disable actual use of the APM
1860 BIOS by passing the "apm=off" option to the kernel at boot time.
1862 Note that the APM support is almost completely disabled for
1863 machines with more than one CPU.
1865 In order to use APM, you will need supporting software. For location
1866 and more information, read <file:Documentation/power/apm-acpi.txt>
1867 and the Battery Powered Linux mini-HOWTO, available from
1868 <http://www.tldp.org/docs.html#howto>.
1870 This driver does not spin down disk drives (see the hdparm(8)
1871 manpage ("man 8 hdparm") for that), and it doesn't turn off
1872 VESA-compliant "green" monitors.
1874 This driver does not support the TI 4000M TravelMate and the ACER
1875 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1876 desktop machines also don't have compliant BIOSes, and this driver
1877 may cause those machines to panic during the boot phase.
1879 Generally, if you don't have a battery in your machine, there isn't
1880 much point in using this driver and you should say N. If you get
1881 random kernel OOPSes or reboots that don't seem to be related to
1882 anything, try disabling/enabling this option (or disabling/enabling
1885 Some other things you should try when experiencing seemingly random,
1888 1) make sure that you have enough swap space and that it is
1890 2) pass the "no-hlt" option to the kernel
1891 3) switch on floating point emulation in the kernel and pass
1892 the "no387" option to the kernel
1893 4) pass the "floppy=nodma" option to the kernel
1894 5) pass the "mem=4M" option to the kernel (thereby disabling
1895 all but the first 4 MB of RAM)
1896 6) make sure that the CPU is not over clocked.
1897 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1898 8) disable the cache from your BIOS settings
1899 9) install a fan for the video card or exchange video RAM
1900 10) install a better fan for the CPU
1901 11) exchange RAM chips
1902 12) exchange the motherboard.
1904 To compile this driver as a module, choose M here: the
1905 module will be called apm.
1909 config APM_IGNORE_USER_SUSPEND
1910 bool "Ignore USER SUSPEND"
1912 This option will ignore USER SUSPEND requests. On machines with a
1913 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1914 series notebooks, it is necessary to say Y because of a BIOS bug.
1916 config APM_DO_ENABLE
1917 bool "Enable PM at boot time"
1919 Enable APM features at boot time. From page 36 of the APM BIOS
1920 specification: "When disabled, the APM BIOS does not automatically
1921 power manage devices, enter the Standby State, enter the Suspend
1922 State, or take power saving steps in response to CPU Idle calls."
1923 This driver will make CPU Idle calls when Linux is idle (unless this
1924 feature is turned off -- see "Do CPU IDLE calls", below). This
1925 should always save battery power, but more complicated APM features
1926 will be dependent on your BIOS implementation. You may need to turn
1927 this option off if your computer hangs at boot time when using APM
1928 support, or if it beeps continuously instead of suspending. Turn
1929 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1930 T400CDT. This is off by default since most machines do fine without
1935 bool "Make CPU Idle calls when idle"
1937 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1938 On some machines, this can activate improved power savings, such as
1939 a slowed CPU clock rate, when the machine is idle. These idle calls
1940 are made after the idle loop has run for some length of time (e.g.,
1941 333 mS). On some machines, this will cause a hang at boot time or
1942 whenever the CPU becomes idle. (On machines with more than one CPU,
1943 this option does nothing.)
1945 config APM_DISPLAY_BLANK
1946 bool "Enable console blanking using APM"
1948 Enable console blanking using the APM. Some laptops can use this to
1949 turn off the LCD backlight when the screen blanker of the Linux
1950 virtual console blanks the screen. Note that this is only used by
1951 the virtual console screen blanker, and won't turn off the backlight
1952 when using the X Window system. This also doesn't have anything to
1953 do with your VESA-compliant power-saving monitor. Further, this
1954 option doesn't work for all laptops -- it might not turn off your
1955 backlight at all, or it might print a lot of errors to the console,
1956 especially if you are using gpm.
1958 config APM_ALLOW_INTS
1959 bool "Allow interrupts during APM BIOS calls"
1961 Normally we disable external interrupts while we are making calls to
1962 the APM BIOS as a measure to lessen the effects of a badly behaving
1963 BIOS implementation. The BIOS should reenable interrupts if it
1964 needs to. Unfortunately, some BIOSes do not -- especially those in
1965 many of the newer IBM Thinkpads. If you experience hangs when you
1966 suspend, try setting this to Y. Otherwise, say N.
1970 source "drivers/cpufreq/Kconfig"
1972 source "drivers/cpuidle/Kconfig"
1974 source "drivers/idle/Kconfig"
1979 menu "Bus options (PCI etc.)"
1984 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1986 Find out whether you have a PCI motherboard. PCI is the name of a
1987 bus system, i.e. the way the CPU talks to the other stuff inside
1988 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1989 VESA. If you have PCI, say Y, otherwise N.
1992 prompt "PCI access mode"
1993 depends on X86_32 && PCI
1996 On PCI systems, the BIOS can be used to detect the PCI devices and
1997 determine their configuration. However, some old PCI motherboards
1998 have BIOS bugs and may crash if this is done. Also, some embedded
1999 PCI-based systems don't have any BIOS at all. Linux can also try to
2000 detect the PCI hardware directly without using the BIOS.
2002 With this option, you can specify how Linux should detect the
2003 PCI devices. If you choose "BIOS", the BIOS will be used,
2004 if you choose "Direct", the BIOS won't be used, and if you
2005 choose "MMConfig", then PCI Express MMCONFIG will be used.
2006 If you choose "Any", the kernel will try MMCONFIG, then the
2007 direct access method and falls back to the BIOS if that doesn't
2008 work. If unsure, go with the default, which is "Any".
2013 config PCI_GOMMCONFIG
2030 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2032 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2035 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2039 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2043 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2047 depends on PCI && XEN
2055 bool "Support mmconfig PCI config space access"
2056 depends on X86_64 && PCI && ACPI
2058 config PCI_CNB20LE_QUIRK
2059 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2062 Read the PCI windows out of the CNB20LE host bridge. This allows
2063 PCI hotplug to work on systems with the CNB20LE chipset which do
2066 There's no public spec for this chipset, and this functionality
2067 is known to be incomplete.
2069 You should say N unless you know you need this.
2071 source "drivers/pci/pcie/Kconfig"
2073 source "drivers/pci/Kconfig"
2075 # x86_64 have no ISA slots, but can have ISA-style DMA.
2077 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2080 Enables ISA-style DMA support for devices requiring such controllers.
2088 Find out whether you have ISA slots on your motherboard. ISA is the
2089 name of a bus system, i.e. the way the CPU talks to the other stuff
2090 inside your box. Other bus systems are PCI, EISA, MicroChannel
2091 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2092 newer boards don't support it. If you have ISA, say Y, otherwise N.
2098 The Extended Industry Standard Architecture (EISA) bus was
2099 developed as an open alternative to the IBM MicroChannel bus.
2101 The EISA bus provided some of the features of the IBM MicroChannel
2102 bus while maintaining backward compatibility with cards made for
2103 the older ISA bus. The EISA bus saw limited use between 1988 and
2104 1995 when it was made obsolete by the PCI bus.
2106 Say Y here if you are building a kernel for an EISA-based machine.
2110 source "drivers/eisa/Kconfig"
2113 tristate "NatSemi SCx200 support"
2115 This provides basic support for National Semiconductor's
2116 (now AMD's) Geode processors. The driver probes for the
2117 PCI-IDs of several on-chip devices, so its a good dependency
2118 for other scx200_* drivers.
2120 If compiled as a module, the driver is named scx200.
2122 config SCx200HR_TIMER
2123 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2127 This driver provides a clocksource built upon the on-chip
2128 27MHz high-resolution timer. Its also a workaround for
2129 NSC Geode SC-1100's buggy TSC, which loses time when the
2130 processor goes idle (as is done by the scheduler). The
2131 other workaround is idle=poll boot option.
2134 bool "One Laptop Per Child support"
2141 Add support for detecting the unique features of the OLPC
2145 bool "OLPC XO-1 Power Management"
2146 depends on OLPC && MFD_CS5535 && PM_SLEEP
2149 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2152 bool "OLPC XO-1 Real Time Clock"
2153 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2155 Add support for the XO-1 real time clock, which can be used as a
2156 programmable wakeup source.
2159 bool "OLPC XO-1 SCI extras"
2160 depends on OLPC && OLPC_XO1_PM
2166 Add support for SCI-based features of the OLPC XO-1 laptop:
2167 - EC-driven system wakeups
2171 - AC adapter status updates
2172 - Battery status updates
2174 config OLPC_XO15_SCI
2175 bool "OLPC XO-1.5 SCI extras"
2176 depends on OLPC && ACPI
2179 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2180 - EC-driven system wakeups
2181 - AC adapter status updates
2182 - Battery status updates
2185 bool "PCEngines ALIX System Support (LED setup)"
2188 This option enables system support for the PCEngines ALIX.
2189 At present this just sets up LEDs for GPIO control on
2190 ALIX2/3/6 boards. However, other system specific setup should
2193 Note: You must still enable the drivers for GPIO and LED support
2194 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2196 Note: You have to set alix.force=1 for boards with Award BIOS.
2199 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2202 This option enables system support for the Soekris Engineering net5501.
2205 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2209 This option enables system support for the Traverse Technologies GEOS.
2212 bool "Technologic Systems TS-5500 platform support"
2214 select CHECK_SIGNATURE
2218 This option enables system support for the Technologic Systems TS-5500.
2224 depends on CPU_SUP_AMD && PCI
2226 source "drivers/pcmcia/Kconfig"
2228 source "drivers/pci/hotplug/Kconfig"
2231 bool "RapidIO support"
2235 If you say Y here, the kernel will include drivers and
2236 infrastructure code to support RapidIO interconnect devices.
2238 source "drivers/rapidio/Kconfig"
2243 menu "Executable file formats / Emulations"
2245 source "fs/Kconfig.binfmt"
2247 config IA32_EMULATION
2248 bool "IA32 Emulation"
2250 select COMPAT_BINFMT_ELF
2253 Include code to run legacy 32-bit programs under a
2254 64-bit kernel. You should likely turn this on, unless you're
2255 100% sure that you don't have any 32-bit programs left.
2258 tristate "IA32 a.out support"
2259 depends on IA32_EMULATION
2261 Support old a.out binaries in the 32bit emulation.
2264 bool "x32 ABI for 64-bit mode"
2265 depends on X86_64 && IA32_EMULATION
2267 Include code to run binaries for the x32 native 32-bit ABI
2268 for 64-bit processors. An x32 process gets access to the
2269 full 64-bit register file and wide data path while leaving
2270 pointers at 32 bits for smaller memory footprint.
2272 You will need a recent binutils (2.22 or later) with
2273 elf32_x86_64 support enabled to compile a kernel with this
2278 depends on IA32_EMULATION || X86_X32
2279 select ARCH_WANT_OLD_COMPAT_IPC
2282 config COMPAT_FOR_U64_ALIGNMENT
2285 config SYSVIPC_COMPAT
2297 config HAVE_ATOMIC_IOMAP
2301 config HAVE_TEXT_POKE_SMP
2303 select STOP_MACHINE if SMP
2305 config X86_DEV_DMA_OPS
2307 depends on X86_64 || STA2X11
2309 config X86_DMA_REMAP
2313 source "net/Kconfig"
2315 source "drivers/Kconfig"
2317 source "drivers/firmware/Kconfig"
2321 source "arch/x86/Kconfig.debug"
2323 source "security/Kconfig"
2325 source "crypto/Kconfig"
2327 source "arch/x86/kvm/Kconfig"
2329 source "lib/Kconfig"
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