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
25 select ARCH_SUPPORTS_NUMA_BALANCING
26 select ARCH_WANTS_PROT_NUMA_PROT_NONE
29 select HAVE_PCSPKR_PLATFORM
30 select HAVE_PERF_EVENTS
32 select HAVE_IOREMAP_PROT
35 select HAVE_MEMBLOCK_NODE_MAP
36 select ARCH_DISCARD_MEMBLOCK
37 select ARCH_WANT_OPTIONAL_GPIOLIB
38 select ARCH_WANT_FRAME_POINTERS
40 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
41 select HAVE_KRETPROBES
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_FUNCTION_TRACER
48 select HAVE_FUNCTION_GRAPH_TRACER
49 select HAVE_FUNCTION_GRAPH_FP_TEST
50 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
51 select HAVE_SYSCALL_TRACEPOINTS
52 select SYSCTL_EXCEPTION_TRACE
55 select HAVE_ARCH_TRACEHOOK
56 select HAVE_GENERIC_DMA_COHERENT if X86_32
57 select HAVE_EFFICIENT_UNALIGNED_ACCESS
58 select USER_STACKTRACE_SUPPORT
59 select HAVE_REGS_AND_STACK_ACCESS_API
60 select HAVE_DMA_API_DEBUG
61 select HAVE_KERNEL_GZIP
62 select HAVE_KERNEL_BZIP2
63 select HAVE_KERNEL_LZMA
65 select HAVE_KERNEL_LZO
66 select HAVE_HW_BREAKPOINT
67 select HAVE_MIXED_BREAKPOINTS_REGS
69 select HAVE_PERF_EVENTS_NMI
71 select HAVE_PERF_USER_STACK_DUMP
72 select HAVE_DEBUG_KMEMLEAK
74 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
75 select HAVE_CMPXCHG_LOCAL
76 select HAVE_CMPXCHG_DOUBLE
77 select HAVE_ARCH_KMEMCHECK
78 select HAVE_USER_RETURN_NOTIFIER
79 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
80 select HAVE_ARCH_JUMP_LABEL
81 select HAVE_TEXT_POKE_SMP
82 select HAVE_GENERIC_HARDIRQS
83 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
85 select GENERIC_FIND_FIRST_BIT
86 select GENERIC_IRQ_PROBE
87 select GENERIC_PENDING_IRQ if SMP
88 select GENERIC_IRQ_SHOW
89 select GENERIC_CLOCKEVENTS_MIN_ADJUST
90 select IRQ_FORCED_THREADING
91 select USE_GENERIC_SMP_HELPERS if SMP
92 select HAVE_BPF_JIT if X86_64
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
95 select ARCH_HAVE_NMI_SAFE_CMPXCHG
97 select DCACHE_WORD_ACCESS
98 select GENERIC_SMP_IDLE_THREAD
99 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
100 select HAVE_ARCH_SECCOMP_FILTER
101 select BUILDTIME_EXTABLE_SORT
102 select GENERIC_CMOS_UPDATE
103 select CLOCKSOURCE_WATCHDOG
104 select GENERIC_CLOCKEVENTS
105 select ARCH_CLOCKSOURCE_DATA if X86_64
106 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
107 select GENERIC_TIME_VSYSCALL if X86_64
108 select KTIME_SCALAR if X86_32
109 select GENERIC_STRNCPY_FROM_USER
110 select GENERIC_STRNLEN_USER
111 select HAVE_CONTEXT_TRACKING if X86_64
112 select HAVE_IRQ_TIME_ACCOUNTING
113 select MODULES_USE_ELF_REL if X86_32
114 select MODULES_USE_ELF_RELA if X86_64
115 select CLONE_BACKWARDS if X86_32
116 select GENERIC_SIGALTSTACK
118 config INSTRUCTION_DECODER
120 depends on KPROBES || PERF_EVENTS || UPROBES
124 default "elf32-i386" if X86_32
125 default "elf64-x86-64" if X86_64
127 config ARCH_DEFCONFIG
129 default "arch/x86/configs/i386_defconfig" if X86_32
130 default "arch/x86/configs/x86_64_defconfig" if X86_64
132 config LOCKDEP_SUPPORT
135 config STACKTRACE_SUPPORT
138 config HAVE_LATENCYTOP_SUPPORT
147 config NEED_DMA_MAP_STATE
149 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
151 config NEED_SG_DMA_LENGTH
154 config GENERIC_ISA_DMA
156 depends on ISA_DMA_API
161 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
163 config GENERIC_BUG_RELATIVE_POINTERS
166 config GENERIC_HWEIGHT
172 config ARCH_MAY_HAVE_PC_FDC
174 depends on ISA_DMA_API
176 config RWSEM_XCHGADD_ALGORITHM
179 config GENERIC_CALIBRATE_DELAY
182 config ARCH_HAS_CPU_RELAX
185 config ARCH_HAS_DEFAULT_IDLE
188 config ARCH_HAS_CACHE_LINE_SIZE
191 config ARCH_HAS_CPU_AUTOPROBE
194 config HAVE_SETUP_PER_CPU_AREA
197 config NEED_PER_CPU_EMBED_FIRST_CHUNK
200 config NEED_PER_CPU_PAGE_FIRST_CHUNK
203 config ARCH_HIBERNATION_POSSIBLE
206 config ARCH_SUSPEND_POSSIBLE
217 config ARCH_SUPPORTS_OPTIMIZED_INLINING
220 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
223 config HAVE_INTEL_TXT
225 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
229 depends on X86_32 && SMP
233 depends on X86_64 && SMP
239 config X86_32_LAZY_GS
241 depends on X86_32 && !CC_STACKPROTECTOR
243 config ARCH_HWEIGHT_CFLAGS
245 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
246 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
248 config ARCH_CPU_PROBE_RELEASE
250 depends on HOTPLUG_CPU
252 config ARCH_SUPPORTS_UPROBES
255 source "init/Kconfig"
256 source "kernel/Kconfig.freezer"
258 menu "Processor type and features"
261 bool "DMA memory allocation support" if EXPERT
264 DMA memory allocation support allows devices with less than 32-bit
265 addressing to allocate within the first 16MB of address space.
266 Disable if no such devices will be used.
271 bool "Symmetric multi-processing support"
273 This enables support for systems with more than one CPU. If you have
274 a system with only one CPU, like most personal computers, say N. If
275 you have a system with more than one CPU, say Y.
277 If you say N here, the kernel will run on single and multiprocessor
278 machines, but will use only one CPU of a multiprocessor machine. If
279 you say Y here, the kernel will run on many, but not all,
280 singleprocessor machines. On a singleprocessor machine, the kernel
281 will run faster if you say N here.
283 Note that if you say Y here and choose architecture "586" or
284 "Pentium" under "Processor family", the kernel will not work on 486
285 architectures. Similarly, multiprocessor kernels for the "PPro"
286 architecture may not work on all Pentium based boards.
288 People using multiprocessor machines who say Y here should also say
289 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
290 Management" code will be disabled if you say Y here.
292 See also <file:Documentation/x86/i386/IO-APIC.txt>,
293 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
294 <http://www.tldp.org/docs.html#howto>.
296 If you don't know what to do here, say N.
299 bool "Support x2apic"
300 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
302 This enables x2apic support on CPUs that have this feature.
304 This allows 32-bit apic IDs (so it can support very large systems),
305 and accesses the local apic via MSRs not via mmio.
307 If you don't know what to do here, say N.
310 bool "Enable MPS table" if ACPI || SFI
312 depends on X86_LOCAL_APIC
314 For old smp systems that do not have proper acpi support. Newer systems
315 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
318 bool "Support for big SMP systems with more than 8 CPUs"
319 depends on X86_32 && SMP
321 This option is needed for the systems that have more than 8 CPUs
325 depends on X86_GOLDFISH
328 config X86_EXTENDED_PLATFORM
329 bool "Support for extended (non-PC) x86 platforms"
332 If you disable this option then the kernel will only support
333 standard PC platforms. (which covers the vast majority of
336 If you enable this option then you'll be able to select support
337 for the following (non-PC) 32 bit x86 platforms:
341 SGI 320/540 (Visual Workstation)
342 STA2X11-based (e.g. Northville)
343 Summit/EXA (IBM x440)
344 Unisys ES7000 IA32 series
345 Moorestown MID devices
347 If you have one of these systems, or if you want to build a
348 generic distribution kernel, say Y here - otherwise say N.
352 config X86_EXTENDED_PLATFORM
353 bool "Support for extended (non-PC) x86 platforms"
356 If you disable this option then the kernel will only support
357 standard PC platforms. (which covers the vast majority of
360 If you enable this option then you'll be able to select support
361 for the following (non-PC) 64 bit x86 platforms:
366 If you have one of these systems, or if you want to build a
367 generic distribution kernel, say Y here - otherwise say N.
369 # This is an alphabetically sorted list of 64 bit extended platforms
370 # Please maintain the alphabetic order if and when there are additions
372 bool "Numascale NumaChip"
374 depends on X86_EXTENDED_PLATFORM
377 depends on X86_X2APIC
378 depends on PCI_MMCONFIG
380 Adds support for Numascale NumaChip large-SMP systems. Needed to
381 enable more than ~168 cores.
382 If you don't have one of these, you should say N here.
386 select PARAVIRT_GUEST
388 depends on X86_64 && PCI
389 depends on X86_EXTENDED_PLATFORM
392 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
393 supposed to run on these EM64T-based machines. Only choose this option
394 if you have one of these machines.
397 bool "SGI Ultraviolet"
399 depends on X86_EXTENDED_PLATFORM
401 depends on X86_X2APIC
403 This option is needed in order to support SGI Ultraviolet systems.
404 If you don't have one of these, you should say N here.
406 # Following is an alphabetically sorted list of 32 bit extended platforms
407 # Please maintain the alphabetic order if and when there are additions
410 bool "Goldfish (Virtual Platform)"
413 Enable support for the Goldfish virtual platform used primarily
414 for Android development. Unless you are building for the Android
415 Goldfish emulator say N here.
418 bool "CE4100 TV platform"
420 depends on PCI_GODIRECT
422 depends on X86_EXTENDED_PLATFORM
423 select X86_REBOOTFIXUPS
425 select OF_EARLY_FLATTREE
428 Select for the Intel CE media processor (CE4100) SOC.
429 This option compiles in support for the CE4100 SOC for settop
430 boxes and media devices.
432 config X86_WANT_INTEL_MID
433 bool "Intel MID platform support"
435 depends on X86_EXTENDED_PLATFORM
437 Select to build a kernel capable of supporting Intel MID platform
438 systems which do not have the PCI legacy interfaces (Moorestown,
439 Medfield). If you are building for a PC class system say N here.
441 if X86_WANT_INTEL_MID
447 bool "Medfield MID platform"
450 depends on X86_IO_APIC
458 select X86_PLATFORM_DEVICES
459 select MFD_INTEL_MSIC
461 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
462 Internet Device(MID) platform.
463 Unlike standard x86 PCs, Medfield does not have many legacy devices
464 nor standard legacy replacement devices/features. e.g. Medfield does
465 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
470 bool "RDC R-321x SoC"
472 depends on X86_EXTENDED_PLATFORM
474 select X86_REBOOTFIXUPS
476 This option is needed for RDC R-321x system-on-chip, also known
478 If you don't have one of these chips, you should say N here.
480 config X86_32_NON_STANDARD
481 bool "Support non-standard 32-bit SMP architectures"
482 depends on X86_32 && SMP
483 depends on X86_EXTENDED_PLATFORM
485 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
486 STA2X11, default subarchitectures. It is intended for a generic
487 binary kernel. If you select them all, kernel will probe it
488 one by one and will fallback to default.
490 # Alphabetically sorted list of Non standard 32 bit platforms
493 bool "NUMAQ (IBM/Sequent)"
494 depends on X86_32_NON_STANDARD
499 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
500 NUMA multiquad box. This changes the way that processors are
501 bootstrapped, and uses Clustered Logical APIC addressing mode instead
502 of Flat Logical. You will need a new lynxer.elf file to flash your
503 firmware with - send email to <Martin.Bligh@us.ibm.com>.
505 config X86_SUPPORTS_MEMORY_FAILURE
507 # MCE code calls memory_failure():
509 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
510 depends on !X86_NUMAQ
511 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
512 depends on X86_64 || !SPARSEMEM
513 select ARCH_SUPPORTS_MEMORY_FAILURE
516 bool "SGI 320/540 (Visual Workstation)"
517 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
518 depends on X86_32_NON_STANDARD
520 The SGI Visual Workstation series is an IA32-based workstation
521 based on SGI systems chips with some legacy PC hardware attached.
523 Say Y here to create a kernel to run on the SGI 320 or 540.
525 A kernel compiled for the Visual Workstation will run on general
526 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
529 bool "STA2X11 Companion Chip Support"
530 depends on X86_32_NON_STANDARD && PCI
531 select X86_DEV_DMA_OPS
535 select ARCH_REQUIRE_GPIOLIB
538 This adds support for boards based on the STA2X11 IO-Hub,
539 a.k.a. "ConneXt". The chip is used in place of the standard
540 PC chipset, so all "standard" peripherals are missing. If this
541 option is selected the kernel will still be able to boot on
542 standard PC machines.
545 bool "Summit/EXA (IBM x440)"
546 depends on X86_32_NON_STANDARD
548 This option is needed for IBM systems that use the Summit/EXA chipset.
549 In particular, it is needed for the x440.
552 bool "Unisys ES7000 IA32 series"
553 depends on X86_32_NON_STANDARD && X86_BIGSMP
555 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
556 supposed to run on an IA32-based Unisys ES7000 system.
559 tristate "Eurobraille/Iris poweroff module"
562 The Iris machines from EuroBraille do not have APM or ACPI support
563 to shut themselves down properly. A special I/O sequence is
564 needed to do so, which is what this module does at
567 This is only for Iris machines from EuroBraille.
571 config SCHED_OMIT_FRAME_POINTER
573 prompt "Single-depth WCHAN output"
576 Calculate simpler /proc/<PID>/wchan values. If this option
577 is disabled then wchan values will recurse back to the
578 caller function. This provides more accurate wchan values,
579 at the expense of slightly more scheduling overhead.
581 If in doubt, say "Y".
583 menuconfig PARAVIRT_GUEST
584 bool "Paravirtualized guest support"
586 Say Y here to get to see options related to running Linux under
587 various hypervisors. This option alone does not add any kernel code.
589 If you say N, all options in this submenu will be skipped and disabled.
593 config PARAVIRT_TIME_ACCOUNTING
594 bool "Paravirtual steal time accounting"
598 Select this option to enable fine granularity task steal time
599 accounting. Time spent executing other tasks in parallel with
600 the current vCPU is discounted from the vCPU power. To account for
601 that, there can be a small performance impact.
603 If in doubt, say N here.
605 source "arch/x86/xen/Kconfig"
608 bool "KVM Guest support (including kvmclock)"
611 select PARAVIRT_CLOCK
612 default y if PARAVIRT_GUEST
614 This option enables various optimizations for running under the KVM
615 hypervisor. It includes a paravirtualized clock, so that instead
616 of relying on a PIT (or probably other) emulation by the
617 underlying device model, the host provides the guest with
618 timing infrastructure such as time of day, and system time
620 source "arch/x86/lguest/Kconfig"
623 bool "Enable paravirtualization code"
625 This changes the kernel so it can modify itself when it is run
626 under a hypervisor, potentially improving performance significantly
627 over full virtualization. However, when run without a hypervisor
628 the kernel is theoretically slower and slightly larger.
630 config PARAVIRT_SPINLOCKS
631 bool "Paravirtualization layer for spinlocks"
632 depends on PARAVIRT && SMP && EXPERIMENTAL
634 Paravirtualized spinlocks allow a pvops backend to replace the
635 spinlock implementation with something virtualization-friendly
636 (for example, block the virtual CPU rather than spinning).
638 Unfortunately the downside is an up to 5% performance hit on
639 native kernels, with various workloads.
641 If you are unsure how to answer this question, answer N.
643 config PARAVIRT_CLOCK
648 config PARAVIRT_DEBUG
649 bool "paravirt-ops debugging"
650 depends on PARAVIRT && DEBUG_KERNEL
652 Enable to debug paravirt_ops internals. Specifically, BUG if
653 a paravirt_op is missing when it is called.
661 This option adds a kernel parameter 'memtest', which allows memtest
663 memtest=0, mean disabled; -- default
664 memtest=1, mean do 1 test pattern;
666 memtest=4, mean do 4 test patterns.
667 If you are unsure how to answer this question, answer N.
669 config X86_SUMMIT_NUMA
671 depends on X86_32 && NUMA && X86_32_NON_STANDARD
673 config X86_CYCLONE_TIMER
675 depends on X86_SUMMIT
677 source "arch/x86/Kconfig.cpu"
681 prompt "HPET Timer Support" if X86_32
683 Use the IA-PC HPET (High Precision Event Timer) to manage
684 time in preference to the PIT and RTC, if a HPET is
686 HPET is the next generation timer replacing legacy 8254s.
687 The HPET provides a stable time base on SMP
688 systems, unlike the TSC, but it is more expensive to access,
689 as it is off-chip. You can find the HPET spec at
690 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
692 You can safely choose Y here. However, HPET will only be
693 activated if the platform and the BIOS support this feature.
694 Otherwise the 8254 will be used for timing services.
696 Choose N to continue using the legacy 8254 timer.
698 config HPET_EMULATE_RTC
700 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
703 def_bool y if X86_INTEL_MID
704 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
706 depends on X86_INTEL_MID && SFI
708 APB timer is the replacement for 8254, HPET on X86 MID platforms.
709 The APBT provides a stable time base on SMP
710 systems, unlike the TSC, but it is more expensive to access,
711 as it is off-chip. APB timers are always running regardless of CPU
712 C states, they are used as per CPU clockevent device when possible.
714 # Mark as expert because too many people got it wrong.
715 # The code disables itself when not needed.
718 bool "Enable DMI scanning" if EXPERT
720 Enabled scanning of DMI to identify machine quirks. Say Y
721 here unless you have verified that your setup is not
722 affected by entries in the DMI blacklist. Required by PNP
726 bool "GART IOMMU support" if EXPERT
729 depends on X86_64 && PCI && AMD_NB
731 Support for full DMA access of devices with 32bit memory access only
732 on systems with more than 3GB. This is usually needed for USB,
733 sound, many IDE/SATA chipsets and some other devices.
734 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
735 based hardware IOMMU and a software bounce buffer based IOMMU used
736 on Intel systems and as fallback.
737 The code is only active when needed (enough memory and limited
738 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
742 bool "IBM Calgary IOMMU support"
744 depends on X86_64 && PCI && EXPERIMENTAL
746 Support for hardware IOMMUs in IBM's xSeries x366 and x460
747 systems. Needed to run systems with more than 3GB of memory
748 properly with 32-bit PCI devices that do not support DAC
749 (Double Address Cycle). Calgary also supports bus level
750 isolation, where all DMAs pass through the IOMMU. This
751 prevents them from going anywhere except their intended
752 destination. This catches hard-to-find kernel bugs and
753 mis-behaving drivers and devices that do not use the DMA-API
754 properly to set up their DMA buffers. The IOMMU can be
755 turned off at boot time with the iommu=off parameter.
756 Normally the kernel will make the right choice by itself.
759 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
761 prompt "Should Calgary be enabled by default?"
762 depends on CALGARY_IOMMU
764 Should Calgary be enabled by default? if you choose 'y', Calgary
765 will be used (if it exists). If you choose 'n', Calgary will not be
766 used even if it exists. If you choose 'n' and would like to use
767 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
770 # need this always selected by IOMMU for the VIA workaround
774 Support for software bounce buffers used on x86-64 systems
775 which don't have a hardware IOMMU. Using this PCI devices
776 which can only access 32-bits of memory can be used on systems
777 with more than 3 GB of memory.
782 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
785 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
786 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
787 select CPUMASK_OFFSTACK
789 Enable maximum number of CPUS and NUMA Nodes for this architecture.
793 int "Maximum number of CPUs" if SMP && !MAXSMP
794 range 2 8 if SMP && X86_32 && !X86_BIGSMP
795 range 2 512 if SMP && !MAXSMP
797 default "4096" if MAXSMP
798 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
801 This allows you to specify the maximum number of CPUs which this
802 kernel will support. The maximum supported value is 512 and the
803 minimum value which makes sense is 2.
805 This is purely to save memory - each supported CPU adds
806 approximately eight kilobytes to the kernel image.
809 bool "SMT (Hyperthreading) scheduler support"
812 SMT scheduler support improves the CPU scheduler's decision making
813 when dealing with Intel Pentium 4 chips with HyperThreading at a
814 cost of slightly increased overhead in some places. If unsure say
819 prompt "Multi-core scheduler support"
822 Multi-core scheduler support improves the CPU scheduler's decision
823 making when dealing with multi-core CPU chips at a cost of slightly
824 increased overhead in some places. If unsure say N here.
826 source "kernel/Kconfig.preempt"
829 bool "Local APIC support on uniprocessors"
830 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
832 A local APIC (Advanced Programmable Interrupt Controller) is an
833 integrated interrupt controller in the CPU. If you have a single-CPU
834 system which has a processor with a local APIC, you can say Y here to
835 enable and use it. If you say Y here even though your machine doesn't
836 have a local APIC, then the kernel will still run with no slowdown at
837 all. The local APIC supports CPU-generated self-interrupts (timer,
838 performance counters), and the NMI watchdog which detects hard
842 bool "IO-APIC support on uniprocessors"
843 depends on X86_UP_APIC
845 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
846 SMP-capable replacement for PC-style interrupt controllers. Most
847 SMP systems and many recent uniprocessor systems have one.
849 If you have a single-CPU system with an IO-APIC, you can say Y here
850 to use it. If you say Y here even though your machine doesn't have
851 an IO-APIC, then the kernel will still run with no slowdown at all.
853 config X86_LOCAL_APIC
855 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
859 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
861 config X86_VISWS_APIC
863 depends on X86_32 && X86_VISWS
865 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
866 bool "Reroute for broken boot IRQs"
867 depends on X86_IO_APIC
869 This option enables a workaround that fixes a source of
870 spurious interrupts. This is recommended when threaded
871 interrupt handling is used on systems where the generation of
872 superfluous "boot interrupts" cannot be disabled.
874 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
875 entry in the chipset's IO-APIC is masked (as, e.g. the RT
876 kernel does during interrupt handling). On chipsets where this
877 boot IRQ generation cannot be disabled, this workaround keeps
878 the original IRQ line masked so that only the equivalent "boot
879 IRQ" is delivered to the CPUs. The workaround also tells the
880 kernel to set up the IRQ handler on the boot IRQ line. In this
881 way only one interrupt is delivered to the kernel. Otherwise
882 the spurious second interrupt may cause the kernel to bring
883 down (vital) interrupt lines.
885 Only affects "broken" chipsets. Interrupt sharing may be
886 increased on these systems.
889 bool "Machine Check / overheating reporting"
892 Machine Check support allows the processor to notify the
893 kernel if it detects a problem (e.g. overheating, data corruption).
894 The action the kernel takes depends on the severity of the problem,
895 ranging from warning messages to halting the machine.
899 prompt "Intel MCE features"
900 depends on X86_MCE && X86_LOCAL_APIC
902 Additional support for intel specific MCE features such as
907 prompt "AMD MCE features"
908 depends on X86_MCE && X86_LOCAL_APIC
910 Additional support for AMD specific MCE features such as
911 the DRAM Error Threshold.
913 config X86_ANCIENT_MCE
914 bool "Support for old Pentium 5 / WinChip machine checks"
915 depends on X86_32 && X86_MCE
917 Include support for machine check handling on old Pentium 5 or WinChip
918 systems. These typically need to be enabled explicitely on the command
921 config X86_MCE_THRESHOLD
922 depends on X86_MCE_AMD || X86_MCE_INTEL
925 config X86_MCE_INJECT
927 tristate "Machine check injector support"
929 Provide support for injecting machine checks for testing purposes.
930 If you don't know what a machine check is and you don't do kernel
931 QA it is safe to say n.
933 config X86_THERMAL_VECTOR
935 depends on X86_MCE_INTEL
938 bool "Enable VM86 support" if EXPERT
942 This option is required by programs like DOSEMU to run 16-bit legacy
943 code on X86 processors. It also may be needed by software like
944 XFree86 to initialize some video cards via BIOS. Disabling this
945 option saves about 6k.
948 tristate "Toshiba Laptop support"
951 This adds a driver to safely access the System Management Mode of
952 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
953 not work on models with a Phoenix BIOS. The System Management Mode
954 is used to set the BIOS and power saving options on Toshiba portables.
956 For information on utilities to make use of this driver see the
957 Toshiba Linux utilities web site at:
958 <http://www.buzzard.org.uk/toshiba/>.
960 Say Y if you intend to run this kernel on a Toshiba portable.
964 tristate "Dell laptop support"
967 This adds a driver to safely access the System Management Mode
968 of the CPU on the Dell Inspiron 8000. The System Management Mode
969 is used to read cpu temperature and cooling fan status and to
970 control the fans on the I8K portables.
972 This driver has been tested only on the Inspiron 8000 but it may
973 also work with other Dell laptops. You can force loading on other
974 models by passing the parameter `force=1' to the module. Use at
977 For information on utilities to make use of this driver see the
978 I8K Linux utilities web site at:
979 <http://people.debian.org/~dz/i8k/>
981 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
984 config X86_REBOOTFIXUPS
985 bool "Enable X86 board specific fixups for reboot"
988 This enables chipset and/or board specific fixups to be done
989 in order to get reboot to work correctly. This is only needed on
990 some combinations of hardware and BIOS. The symptom, for which
991 this config is intended, is when reboot ends with a stalled/hung
994 Currently, the only fixup is for the Geode machines using
995 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
997 Say Y if you want to enable the fixup. Currently, it's safe to
998 enable this option even if you don't need it.
1002 tristate "CPU microcode loading support"
1006 If you say Y here, you will be able to update the microcode on
1007 certain Intel and AMD processors. The Intel support is for the
1008 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1009 Xeon etc. The AMD support is for families 0x10 and later. You will
1010 obviously need the actual microcode binary data itself which is not
1011 shipped with the Linux kernel.
1013 This option selects the general module only, you need to select
1014 at least one vendor specific module as well.
1016 To compile this driver as a module, choose M here: the module
1017 will be called microcode.
1019 config MICROCODE_INTEL
1020 bool "Intel microcode loading support"
1021 depends on MICROCODE
1025 This options enables microcode patch loading support for Intel
1028 For latest news and information on obtaining all the required
1029 Intel ingredients for this driver, check:
1030 <http://www.urbanmyth.org/microcode/>.
1032 config MICROCODE_AMD
1033 bool "AMD microcode loading support"
1034 depends on MICROCODE
1037 If you select this option, microcode patch loading support for AMD
1038 processors will be enabled.
1040 config MICROCODE_OLD_INTERFACE
1042 depends on MICROCODE
1045 tristate "/dev/cpu/*/msr - Model-specific register support"
1047 This device gives privileged processes access to the x86
1048 Model-Specific Registers (MSRs). It is a character device with
1049 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1050 MSR accesses are directed to a specific CPU on multi-processor
1054 tristate "/dev/cpu/*/cpuid - CPU information support"
1056 This device gives processes access to the x86 CPUID instruction to
1057 be executed on a specific processor. It is a character device
1058 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1062 prompt "High Memory Support"
1063 default HIGHMEM64G if X86_NUMAQ
1069 depends on !X86_NUMAQ
1071 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1072 However, the address space of 32-bit x86 processors is only 4
1073 Gigabytes large. That means that, if you have a large amount of
1074 physical memory, not all of it can be "permanently mapped" by the
1075 kernel. The physical memory that's not permanently mapped is called
1078 If you are compiling a kernel which will never run on a machine with
1079 more than 1 Gigabyte total physical RAM, answer "off" here (default
1080 choice and suitable for most users). This will result in a "3GB/1GB"
1081 split: 3GB are mapped so that each process sees a 3GB virtual memory
1082 space and the remaining part of the 4GB virtual memory space is used
1083 by the kernel to permanently map as much physical memory as
1086 If the machine has between 1 and 4 Gigabytes physical RAM, then
1089 If more than 4 Gigabytes is used then answer "64GB" here. This
1090 selection turns Intel PAE (Physical Address Extension) mode on.
1091 PAE implements 3-level paging on IA32 processors. PAE is fully
1092 supported by Linux, PAE mode is implemented on all recent Intel
1093 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1094 then the kernel will not boot on CPUs that don't support PAE!
1096 The actual amount of total physical memory will either be
1097 auto detected or can be forced by using a kernel command line option
1098 such as "mem=256M". (Try "man bootparam" or see the documentation of
1099 your boot loader (lilo or loadlin) about how to pass options to the
1100 kernel at boot time.)
1102 If unsure, say "off".
1106 depends on !X86_NUMAQ
1108 Select this if you have a 32-bit processor and between 1 and 4
1109 gigabytes of physical RAM.
1116 Select this if you have a 32-bit processor and more than 4
1117 gigabytes of physical RAM.
1122 depends on EXPERIMENTAL
1123 prompt "Memory split" if EXPERT
1127 Select the desired split between kernel and user memory.
1129 If the address range available to the kernel is less than the
1130 physical memory installed, the remaining memory will be available
1131 as "high memory". Accessing high memory is a little more costly
1132 than low memory, as it needs to be mapped into the kernel first.
1133 Note that increasing the kernel address space limits the range
1134 available to user programs, making the address space there
1135 tighter. Selecting anything other than the default 3G/1G split
1136 will also likely make your kernel incompatible with binary-only
1139 If you are not absolutely sure what you are doing, leave this
1143 bool "3G/1G user/kernel split"
1144 config VMSPLIT_3G_OPT
1146 bool "3G/1G user/kernel split (for full 1G low memory)"
1148 bool "2G/2G user/kernel split"
1149 config VMSPLIT_2G_OPT
1151 bool "2G/2G user/kernel split (for full 2G low memory)"
1153 bool "1G/3G user/kernel split"
1158 default 0xB0000000 if VMSPLIT_3G_OPT
1159 default 0x80000000 if VMSPLIT_2G
1160 default 0x78000000 if VMSPLIT_2G_OPT
1161 default 0x40000000 if VMSPLIT_1G
1167 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1170 bool "PAE (Physical Address Extension) Support"
1171 depends on X86_32 && !HIGHMEM4G
1173 PAE is required for NX support, and furthermore enables
1174 larger swapspace support for non-overcommit purposes. It
1175 has the cost of more pagetable lookup overhead, and also
1176 consumes more pagetable space per process.
1178 config ARCH_PHYS_ADDR_T_64BIT
1180 depends on X86_64 || X86_PAE
1182 config ARCH_DMA_ADDR_T_64BIT
1184 depends on X86_64 || HIGHMEM64G
1186 config DIRECT_GBPAGES
1187 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1191 Allow the kernel linear mapping to use 1GB pages on CPUs that
1192 support it. This can improve the kernel's performance a tiny bit by
1193 reducing TLB pressure. If in doubt, say "Y".
1195 # Common NUMA Features
1197 bool "Numa Memory Allocation and Scheduler Support"
1199 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1200 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1202 Enable NUMA (Non Uniform Memory Access) support.
1204 The kernel will try to allocate memory used by a CPU on the
1205 local memory controller of the CPU and add some more
1206 NUMA awareness to the kernel.
1208 For 64-bit this is recommended if the system is Intel Core i7
1209 (or later), AMD Opteron, or EM64T NUMA.
1211 For 32-bit this is only needed on (rare) 32-bit-only platforms
1212 that support NUMA topologies, such as NUMAQ / Summit, or if you
1213 boot a 32-bit kernel on a 64-bit NUMA platform.
1215 Otherwise, you should say N.
1217 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1218 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1222 prompt "Old style AMD Opteron NUMA detection"
1223 depends on X86_64 && NUMA && PCI
1225 Enable AMD NUMA node topology detection. You should say Y here if
1226 you have a multi processor AMD system. This uses an old method to
1227 read the NUMA configuration directly from the builtin Northbridge
1228 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1229 which also takes priority if both are compiled in.
1231 config X86_64_ACPI_NUMA
1233 prompt "ACPI NUMA detection"
1234 depends on X86_64 && NUMA && ACPI && PCI
1237 Enable ACPI SRAT based node topology detection.
1239 # Some NUMA nodes have memory ranges that span
1240 # other nodes. Even though a pfn is valid and
1241 # between a node's start and end pfns, it may not
1242 # reside on that node. See memmap_init_zone()
1244 config NODES_SPAN_OTHER_NODES
1246 depends on X86_64_ACPI_NUMA
1249 bool "NUMA emulation"
1252 Enable NUMA emulation. A flat machine will be split
1253 into virtual nodes when booted with "numa=fake=N", where N is the
1254 number of nodes. This is only useful for debugging.
1257 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1259 default "10" if MAXSMP
1260 default "6" if X86_64
1261 default "4" if X86_NUMAQ
1263 depends on NEED_MULTIPLE_NODES
1265 Specify the maximum number of NUMA Nodes available on the target
1266 system. Increases memory reserved to accommodate various tables.
1268 config HAVE_ARCH_ALLOC_REMAP
1270 depends on X86_32 && NUMA
1272 config ARCH_HAVE_MEMORY_PRESENT
1274 depends on X86_32 && DISCONTIGMEM
1276 config NEED_NODE_MEMMAP_SIZE
1278 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1280 config ARCH_FLATMEM_ENABLE
1282 depends on X86_32 && !NUMA
1284 config ARCH_DISCONTIGMEM_ENABLE
1286 depends on NUMA && X86_32
1288 config ARCH_DISCONTIGMEM_DEFAULT
1290 depends on NUMA && X86_32
1292 config ARCH_SPARSEMEM_ENABLE
1294 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1295 select SPARSEMEM_STATIC if X86_32
1296 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1298 config ARCH_SPARSEMEM_DEFAULT
1302 config ARCH_SELECT_MEMORY_MODEL
1304 depends on ARCH_SPARSEMEM_ENABLE
1306 config ARCH_MEMORY_PROBE
1308 depends on X86_64 && MEMORY_HOTPLUG
1310 config ARCH_PROC_KCORE_TEXT
1312 depends on X86_64 && PROC_KCORE
1314 config ILLEGAL_POINTER_VALUE
1317 default 0xdead000000000000 if X86_64
1322 bool "Allocate 3rd-level pagetables from highmem"
1325 The VM uses one page table entry for each page of physical memory.
1326 For systems with a lot of RAM, this can be wasteful of precious
1327 low memory. Setting this option will put user-space page table
1328 entries in high memory.
1330 config X86_CHECK_BIOS_CORRUPTION
1331 bool "Check for low memory corruption"
1333 Periodically check for memory corruption in low memory, which
1334 is suspected to be caused by BIOS. Even when enabled in the
1335 configuration, it is disabled at runtime. Enable it by
1336 setting "memory_corruption_check=1" on the kernel command
1337 line. By default it scans the low 64k of memory every 60
1338 seconds; see the memory_corruption_check_size and
1339 memory_corruption_check_period parameters in
1340 Documentation/kernel-parameters.txt to adjust this.
1342 When enabled with the default parameters, this option has
1343 almost no overhead, as it reserves a relatively small amount
1344 of memory and scans it infrequently. It both detects corruption
1345 and prevents it from affecting the running system.
1347 It is, however, intended as a diagnostic tool; if repeatable
1348 BIOS-originated corruption always affects the same memory,
1349 you can use memmap= to prevent the kernel from using that
1352 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1353 bool "Set the default setting of memory_corruption_check"
1354 depends on X86_CHECK_BIOS_CORRUPTION
1357 Set whether the default state of memory_corruption_check is
1360 config X86_RESERVE_LOW
1361 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1365 Specify the amount of low memory to reserve for the BIOS.
1367 The first page contains BIOS data structures that the kernel
1368 must not use, so that page must always be reserved.
1370 By default we reserve the first 64K of physical RAM, as a
1371 number of BIOSes are known to corrupt that memory range
1372 during events such as suspend/resume or monitor cable
1373 insertion, so it must not be used by the kernel.
1375 You can set this to 4 if you are absolutely sure that you
1376 trust the BIOS to get all its memory reservations and usages
1377 right. If you know your BIOS have problems beyond the
1378 default 64K area, you can set this to 640 to avoid using the
1379 entire low memory range.
1381 If you have doubts about the BIOS (e.g. suspend/resume does
1382 not work or there's kernel crashes after certain hardware
1383 hotplug events) then you might want to enable
1384 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1385 typical corruption patterns.
1387 Leave this to the default value of 64 if you are unsure.
1389 config MATH_EMULATION
1391 prompt "Math emulation" if X86_32
1393 Linux can emulate a math coprocessor (used for floating point
1394 operations) if you don't have one. 486DX and Pentium processors have
1395 a math coprocessor built in, 486SX and 386 do not, unless you added
1396 a 487DX or 387, respectively. (The messages during boot time can
1397 give you some hints here ["man dmesg"].) Everyone needs either a
1398 coprocessor or this emulation.
1400 If you don't have a math coprocessor, you need to say Y here; if you
1401 say Y here even though you have a coprocessor, the coprocessor will
1402 be used nevertheless. (This behavior can be changed with the kernel
1403 command line option "no387", which comes handy if your coprocessor
1404 is broken. Try "man bootparam" or see the documentation of your boot
1405 loader (lilo or loadlin) about how to pass options to the kernel at
1406 boot time.) This means that it is a good idea to say Y here if you
1407 intend to use this kernel on different machines.
1409 More information about the internals of the Linux math coprocessor
1410 emulation can be found in <file:arch/x86/math-emu/README>.
1412 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1413 kernel, it won't hurt.
1417 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1419 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1420 the Memory Type Range Registers (MTRRs) may be used to control
1421 processor access to memory ranges. This is most useful if you have
1422 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1423 allows bus write transfers to be combined into a larger transfer
1424 before bursting over the PCI/AGP bus. This can increase performance
1425 of image write operations 2.5 times or more. Saying Y here creates a
1426 /proc/mtrr file which may be used to manipulate your processor's
1427 MTRRs. Typically the X server should use this.
1429 This code has a reasonably generic interface so that similar
1430 control registers on other processors can be easily supported
1433 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1434 Registers (ARRs) which provide a similar functionality to MTRRs. For
1435 these, the ARRs are used to emulate the MTRRs.
1436 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1437 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1438 write-combining. All of these processors are supported by this code
1439 and it makes sense to say Y here if you have one of them.
1441 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1442 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1443 can lead to all sorts of problems, so it's good to say Y here.
1445 You can safely say Y even if your machine doesn't have MTRRs, you'll
1446 just add about 9 KB to your kernel.
1448 See <file:Documentation/x86/mtrr.txt> for more information.
1450 config MTRR_SANITIZER
1452 prompt "MTRR cleanup support"
1455 Convert MTRR layout from continuous to discrete, so X drivers can
1456 add writeback entries.
1458 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1459 The largest mtrr entry size for a continuous block can be set with
1464 config MTRR_SANITIZER_ENABLE_DEFAULT
1465 int "MTRR cleanup enable value (0-1)"
1468 depends on MTRR_SANITIZER
1470 Enable mtrr cleanup default value
1472 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1473 int "MTRR cleanup spare reg num (0-7)"
1476 depends on MTRR_SANITIZER
1478 mtrr cleanup spare entries default, it can be changed via
1479 mtrr_spare_reg_nr=N on the kernel command line.
1483 prompt "x86 PAT support" if EXPERT
1486 Use PAT attributes to setup page level cache control.
1488 PATs are the modern equivalents of MTRRs and are much more
1489 flexible than MTRRs.
1491 Say N here if you see bootup problems (boot crash, boot hang,
1492 spontaneous reboots) or a non-working video driver.
1496 config ARCH_USES_PG_UNCACHED
1502 prompt "x86 architectural random number generator" if EXPERT
1504 Enable the x86 architectural RDRAND instruction
1505 (Intel Bull Mountain technology) to generate random numbers.
1506 If supported, this is a high bandwidth, cryptographically
1507 secure hardware random number generator.
1511 prompt "Supervisor Mode Access Prevention" if EXPERT
1513 Supervisor Mode Access Prevention (SMAP) is a security
1514 feature in newer Intel processors. There is a small
1515 performance cost if this enabled and turned on; there is
1516 also a small increase in the kernel size if this is enabled.
1521 bool "EFI runtime service support"
1524 This enables the kernel to use EFI runtime services that are
1525 available (such as the EFI variable services).
1527 This option is only useful on systems that have EFI firmware.
1528 In addition, you should use the latest ELILO loader available
1529 at <http://elilo.sourceforge.net> in order to take advantage
1530 of EFI runtime services. However, even with this option, the
1531 resultant kernel should continue to boot on existing non-EFI
1535 bool "EFI stub support"
1538 This kernel feature allows a bzImage to be loaded directly
1539 by EFI firmware without the use of a bootloader.
1541 See Documentation/x86/efi-stub.txt for more information.
1545 prompt "Enable seccomp to safely compute untrusted bytecode"
1547 This kernel feature is useful for number crunching applications
1548 that may need to compute untrusted bytecode during their
1549 execution. By using pipes or other transports made available to
1550 the process as file descriptors supporting the read/write
1551 syscalls, it's possible to isolate those applications in
1552 their own address space using seccomp. Once seccomp is
1553 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1554 and the task is only allowed to execute a few safe syscalls
1555 defined by each seccomp mode.
1557 If unsure, say Y. Only embedded should say N here.
1559 config CC_STACKPROTECTOR
1560 bool "Enable -fstack-protector buffer overflow detection"
1562 This option turns on the -fstack-protector GCC feature. This
1563 feature puts, at the beginning of functions, a canary value on
1564 the stack just before the return address, and validates
1565 the value just before actually returning. Stack based buffer
1566 overflows (that need to overwrite this return address) now also
1567 overwrite the canary, which gets detected and the attack is then
1568 neutralized via a kernel panic.
1570 This feature requires gcc version 4.2 or above, or a distribution
1571 gcc with the feature backported. Older versions are automatically
1572 detected and for those versions, this configuration option is
1573 ignored. (and a warning is printed during bootup)
1575 source kernel/Kconfig.hz
1578 bool "kexec system call"
1580 kexec is a system call that implements the ability to shutdown your
1581 current kernel, and to start another kernel. It is like a reboot
1582 but it is independent of the system firmware. And like a reboot
1583 you can start any kernel with it, not just Linux.
1585 The name comes from the similarity to the exec system call.
1587 It is an ongoing process to be certain the hardware in a machine
1588 is properly shutdown, so do not be surprised if this code does not
1589 initially work for you. It may help to enable device hotplugging
1590 support. As of this writing the exact hardware interface is
1591 strongly in flux, so no good recommendation can be made.
1594 bool "kernel crash dumps"
1595 depends on X86_64 || (X86_32 && HIGHMEM)
1597 Generate crash dump after being started by kexec.
1598 This should be normally only set in special crash dump kernels
1599 which are loaded in the main kernel with kexec-tools into
1600 a specially reserved region and then later executed after
1601 a crash by kdump/kexec. The crash dump kernel must be compiled
1602 to a memory address not used by the main kernel or BIOS using
1603 PHYSICAL_START, or it must be built as a relocatable image
1604 (CONFIG_RELOCATABLE=y).
1605 For more details see Documentation/kdump/kdump.txt
1608 bool "kexec jump (EXPERIMENTAL)"
1609 depends on EXPERIMENTAL
1610 depends on KEXEC && HIBERNATION
1612 Jump between original kernel and kexeced kernel and invoke
1613 code in physical address mode via KEXEC
1615 config PHYSICAL_START
1616 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1619 This gives the physical address where the kernel is loaded.
1621 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1622 bzImage will decompress itself to above physical address and
1623 run from there. Otherwise, bzImage will run from the address where
1624 it has been loaded by the boot loader and will ignore above physical
1627 In normal kdump cases one does not have to set/change this option
1628 as now bzImage can be compiled as a completely relocatable image
1629 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1630 address. This option is mainly useful for the folks who don't want
1631 to use a bzImage for capturing the crash dump and want to use a
1632 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1633 to be specifically compiled to run from a specific memory area
1634 (normally a reserved region) and this option comes handy.
1636 So if you are using bzImage for capturing the crash dump,
1637 leave the value here unchanged to 0x1000000 and set
1638 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1639 for capturing the crash dump change this value to start of
1640 the reserved region. In other words, it can be set based on
1641 the "X" value as specified in the "crashkernel=YM@XM"
1642 command line boot parameter passed to the panic-ed
1643 kernel. Please take a look at Documentation/kdump/kdump.txt
1644 for more details about crash dumps.
1646 Usage of bzImage for capturing the crash dump is recommended as
1647 one does not have to build two kernels. Same kernel can be used
1648 as production kernel and capture kernel. Above option should have
1649 gone away after relocatable bzImage support is introduced. But it
1650 is present because there are users out there who continue to use
1651 vmlinux for dump capture. This option should go away down the
1654 Don't change this unless you know what you are doing.
1657 bool "Build a relocatable kernel"
1660 This builds a kernel image that retains relocation information
1661 so it can be loaded someplace besides the default 1MB.
1662 The relocations tend to make the kernel binary about 10% larger,
1663 but are discarded at runtime.
1665 One use is for the kexec on panic case where the recovery kernel
1666 must live at a different physical address than the primary
1669 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1670 it has been loaded at and the compile time physical address
1671 (CONFIG_PHYSICAL_START) is ignored.
1673 # Relocation on x86-32 needs some additional build support
1674 config X86_NEED_RELOCS
1676 depends on X86_32 && RELOCATABLE
1678 config PHYSICAL_ALIGN
1679 hex "Alignment value to which kernel should be aligned" if X86_32
1681 range 0x2000 0x1000000
1683 This value puts the alignment restrictions on physical address
1684 where kernel is loaded and run from. Kernel is compiled for an
1685 address which meets above alignment restriction.
1687 If bootloader loads the kernel at a non-aligned address and
1688 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1689 address aligned to above value and run from there.
1691 If bootloader loads the kernel at a non-aligned address and
1692 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1693 load address and decompress itself to the address it has been
1694 compiled for and run from there. The address for which kernel is
1695 compiled already meets above alignment restrictions. Hence the
1696 end result is that kernel runs from a physical address meeting
1697 above alignment restrictions.
1699 Don't change this unless you know what you are doing.
1702 bool "Support for hot-pluggable CPUs"
1703 depends on SMP && HOTPLUG
1705 Say Y here to allow turning CPUs off and on. CPUs can be
1706 controlled through /sys/devices/system/cpu.
1707 ( Note: power management support will enable this option
1708 automatically on SMP systems. )
1709 Say N if you want to disable CPU hotplug.
1711 config BOOTPARAM_HOTPLUG_CPU0
1712 bool "Set default setting of cpu0_hotpluggable"
1714 depends on HOTPLUG_CPU && EXPERIMENTAL
1716 Set whether default state of cpu0_hotpluggable is on or off.
1718 Say Y here to enable CPU0 hotplug by default. If this switch
1719 is turned on, there is no need to give cpu0_hotplug kernel
1720 parameter and the CPU0 hotplug feature is enabled by default.
1722 Please note: there are two known CPU0 dependencies if you want
1723 to enable the CPU0 hotplug feature either by this switch or by
1724 cpu0_hotplug kernel parameter.
1726 First, resume from hibernate or suspend always starts from CPU0.
1727 So hibernate and suspend are prevented if CPU0 is offline.
1729 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1730 offline if any interrupt can not migrate out of CPU0. There may
1731 be other CPU0 dependencies.
1733 Please make sure the dependencies are under your control before
1734 you enable this feature.
1736 Say N if you don't want to enable CPU0 hotplug feature by default.
1737 You still can enable the CPU0 hotplug feature at boot by kernel
1738 parameter cpu0_hotplug.
1740 config DEBUG_HOTPLUG_CPU0
1742 prompt "Debug CPU0 hotplug"
1743 depends on HOTPLUG_CPU && EXPERIMENTAL
1745 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1746 soon as possible and boots up userspace with CPU0 offlined. User
1747 can online CPU0 back after boot time.
1749 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1750 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1751 compilation or giving cpu0_hotplug kernel parameter at boot.
1757 prompt "Compat VDSO support"
1758 depends on X86_32 || IA32_EMULATION
1760 Map the 32-bit VDSO to the predictable old-style address too.
1762 Say N here if you are running a sufficiently recent glibc
1763 version (2.3.3 or later), to remove the high-mapped
1764 VDSO mapping and to exclusively use the randomized VDSO.
1769 bool "Built-in kernel command line"
1771 Allow for specifying boot arguments to the kernel at
1772 build time. On some systems (e.g. embedded ones), it is
1773 necessary or convenient to provide some or all of the
1774 kernel boot arguments with the kernel itself (that is,
1775 to not rely on the boot loader to provide them.)
1777 To compile command line arguments into the kernel,
1778 set this option to 'Y', then fill in the
1779 the boot arguments in CONFIG_CMDLINE.
1781 Systems with fully functional boot loaders (i.e. non-embedded)
1782 should leave this option set to 'N'.
1785 string "Built-in kernel command string"
1786 depends on CMDLINE_BOOL
1789 Enter arguments here that should be compiled into the kernel
1790 image and used at boot time. If the boot loader provides a
1791 command line at boot time, it is appended to this string to
1792 form the full kernel command line, when the system boots.
1794 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1795 change this behavior.
1797 In most cases, the command line (whether built-in or provided
1798 by the boot loader) should specify the device for the root
1801 config CMDLINE_OVERRIDE
1802 bool "Built-in command line overrides boot loader arguments"
1803 depends on CMDLINE_BOOL
1805 Set this option to 'Y' to have the kernel ignore the boot loader
1806 command line, and use ONLY the built-in command line.
1808 This is used to work around broken boot loaders. This should
1809 be set to 'N' under normal conditions.
1813 config ARCH_ENABLE_MEMORY_HOTPLUG
1815 depends on X86_64 || (X86_32 && HIGHMEM)
1817 config ARCH_ENABLE_MEMORY_HOTREMOVE
1819 depends on MEMORY_HOTPLUG
1821 config USE_PERCPU_NUMA_NODE_ID
1825 menu "Power management and ACPI options"
1827 config ARCH_HIBERNATION_HEADER
1829 depends on X86_64 && HIBERNATION
1831 source "kernel/power/Kconfig"
1833 source "drivers/acpi/Kconfig"
1835 source "drivers/sfi/Kconfig"
1842 tristate "APM (Advanced Power Management) BIOS support"
1843 depends on X86_32 && PM_SLEEP
1845 APM is a BIOS specification for saving power using several different
1846 techniques. This is mostly useful for battery powered laptops with
1847 APM compliant BIOSes. If you say Y here, the system time will be
1848 reset after a RESUME operation, the /proc/apm device will provide
1849 battery status information, and user-space programs will receive
1850 notification of APM "events" (e.g. battery status change).
1852 If you select "Y" here, you can disable actual use of the APM
1853 BIOS by passing the "apm=off" option to the kernel at boot time.
1855 Note that the APM support is almost completely disabled for
1856 machines with more than one CPU.
1858 In order to use APM, you will need supporting software. For location
1859 and more information, read <file:Documentation/power/apm-acpi.txt>
1860 and the Battery Powered Linux mini-HOWTO, available from
1861 <http://www.tldp.org/docs.html#howto>.
1863 This driver does not spin down disk drives (see the hdparm(8)
1864 manpage ("man 8 hdparm") for that), and it doesn't turn off
1865 VESA-compliant "green" monitors.
1867 This driver does not support the TI 4000M TravelMate and the ACER
1868 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1869 desktop machines also don't have compliant BIOSes, and this driver
1870 may cause those machines to panic during the boot phase.
1872 Generally, if you don't have a battery in your machine, there isn't
1873 much point in using this driver and you should say N. If you get
1874 random kernel OOPSes or reboots that don't seem to be related to
1875 anything, try disabling/enabling this option (or disabling/enabling
1878 Some other things you should try when experiencing seemingly random,
1881 1) make sure that you have enough swap space and that it is
1883 2) pass the "no-hlt" option to the kernel
1884 3) switch on floating point emulation in the kernel and pass
1885 the "no387" option to the kernel
1886 4) pass the "floppy=nodma" option to the kernel
1887 5) pass the "mem=4M" option to the kernel (thereby disabling
1888 all but the first 4 MB of RAM)
1889 6) make sure that the CPU is not over clocked.
1890 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1891 8) disable the cache from your BIOS settings
1892 9) install a fan for the video card or exchange video RAM
1893 10) install a better fan for the CPU
1894 11) exchange RAM chips
1895 12) exchange the motherboard.
1897 To compile this driver as a module, choose M here: the
1898 module will be called apm.
1902 config APM_IGNORE_USER_SUSPEND
1903 bool "Ignore USER SUSPEND"
1905 This option will ignore USER SUSPEND requests. On machines with a
1906 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1907 series notebooks, it is necessary to say Y because of a BIOS bug.
1909 config APM_DO_ENABLE
1910 bool "Enable PM at boot time"
1912 Enable APM features at boot time. From page 36 of the APM BIOS
1913 specification: "When disabled, the APM BIOS does not automatically
1914 power manage devices, enter the Standby State, enter the Suspend
1915 State, or take power saving steps in response to CPU Idle calls."
1916 This driver will make CPU Idle calls when Linux is idle (unless this
1917 feature is turned off -- see "Do CPU IDLE calls", below). This
1918 should always save battery power, but more complicated APM features
1919 will be dependent on your BIOS implementation. You may need to turn
1920 this option off if your computer hangs at boot time when using APM
1921 support, or if it beeps continuously instead of suspending. Turn
1922 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1923 T400CDT. This is off by default since most machines do fine without
1927 bool "Make CPU Idle calls when idle"
1929 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1930 On some machines, this can activate improved power savings, such as
1931 a slowed CPU clock rate, when the machine is idle. These idle calls
1932 are made after the idle loop has run for some length of time (e.g.,
1933 333 mS). On some machines, this will cause a hang at boot time or
1934 whenever the CPU becomes idle. (On machines with more than one CPU,
1935 this option does nothing.)
1937 config APM_DISPLAY_BLANK
1938 bool "Enable console blanking using APM"
1940 Enable console blanking using the APM. Some laptops can use this to
1941 turn off the LCD backlight when the screen blanker of the Linux
1942 virtual console blanks the screen. Note that this is only used by
1943 the virtual console screen blanker, and won't turn off the backlight
1944 when using the X Window system. This also doesn't have anything to
1945 do with your VESA-compliant power-saving monitor. Further, this
1946 option doesn't work for all laptops -- it might not turn off your
1947 backlight at all, or it might print a lot of errors to the console,
1948 especially if you are using gpm.
1950 config APM_ALLOW_INTS
1951 bool "Allow interrupts during APM BIOS calls"
1953 Normally we disable external interrupts while we are making calls to
1954 the APM BIOS as a measure to lessen the effects of a badly behaving
1955 BIOS implementation. The BIOS should reenable interrupts if it
1956 needs to. Unfortunately, some BIOSes do not -- especially those in
1957 many of the newer IBM Thinkpads. If you experience hangs when you
1958 suspend, try setting this to Y. Otherwise, say N.
1962 source "drivers/cpufreq/Kconfig"
1964 source "drivers/cpuidle/Kconfig"
1966 source "drivers/idle/Kconfig"
1971 menu "Bus options (PCI etc.)"
1976 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1978 Find out whether you have a PCI motherboard. PCI is the name of a
1979 bus system, i.e. the way the CPU talks to the other stuff inside
1980 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1981 VESA. If you have PCI, say Y, otherwise N.
1984 prompt "PCI access mode"
1985 depends on X86_32 && PCI
1988 On PCI systems, the BIOS can be used to detect the PCI devices and
1989 determine their configuration. However, some old PCI motherboards
1990 have BIOS bugs and may crash if this is done. Also, some embedded
1991 PCI-based systems don't have any BIOS at all. Linux can also try to
1992 detect the PCI hardware directly without using the BIOS.
1994 With this option, you can specify how Linux should detect the
1995 PCI devices. If you choose "BIOS", the BIOS will be used,
1996 if you choose "Direct", the BIOS won't be used, and if you
1997 choose "MMConfig", then PCI Express MMCONFIG will be used.
1998 If you choose "Any", the kernel will try MMCONFIG, then the
1999 direct access method and falls back to the BIOS if that doesn't
2000 work. If unsure, go with the default, which is "Any".
2005 config PCI_GOMMCONFIG
2022 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2024 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2027 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2031 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2035 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2039 depends on PCI && XEN
2047 bool "Support mmconfig PCI config space access"
2048 depends on X86_64 && PCI && ACPI
2050 config PCI_CNB20LE_QUIRK
2051 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2052 depends on PCI && EXPERIMENTAL
2054 Read the PCI windows out of the CNB20LE host bridge. This allows
2055 PCI hotplug to work on systems with the CNB20LE chipset which do
2058 There's no public spec for this chipset, and this functionality
2059 is known to be incomplete.
2061 You should say N unless you know you need this.
2063 source "drivers/pci/pcie/Kconfig"
2065 source "drivers/pci/Kconfig"
2067 # x86_64 have no ISA slots, but can have ISA-style DMA.
2069 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2072 Enables ISA-style DMA support for devices requiring such controllers.
2080 Find out whether you have ISA slots on your motherboard. ISA is the
2081 name of a bus system, i.e. the way the CPU talks to the other stuff
2082 inside your box. Other bus systems are PCI, EISA, MicroChannel
2083 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2084 newer boards don't support it. If you have ISA, say Y, otherwise N.
2090 The Extended Industry Standard Architecture (EISA) bus was
2091 developed as an open alternative to the IBM MicroChannel bus.
2093 The EISA bus provided some of the features of the IBM MicroChannel
2094 bus while maintaining backward compatibility with cards made for
2095 the older ISA bus. The EISA bus saw limited use between 1988 and
2096 1995 when it was made obsolete by the PCI bus.
2098 Say Y here if you are building a kernel for an EISA-based machine.
2102 source "drivers/eisa/Kconfig"
2105 tristate "NatSemi SCx200 support"
2107 This provides basic support for National Semiconductor's
2108 (now AMD's) Geode processors. The driver probes for the
2109 PCI-IDs of several on-chip devices, so its a good dependency
2110 for other scx200_* drivers.
2112 If compiled as a module, the driver is named scx200.
2114 config SCx200HR_TIMER
2115 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2119 This driver provides a clocksource built upon the on-chip
2120 27MHz high-resolution timer. Its also a workaround for
2121 NSC Geode SC-1100's buggy TSC, which loses time when the
2122 processor goes idle (as is done by the scheduler). The
2123 other workaround is idle=poll boot option.
2126 bool "One Laptop Per Child support"
2133 Add support for detecting the unique features of the OLPC
2137 bool "OLPC XO-1 Power Management"
2138 depends on OLPC && MFD_CS5535 && PM_SLEEP
2141 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2144 bool "OLPC XO-1 Real Time Clock"
2145 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2147 Add support for the XO-1 real time clock, which can be used as a
2148 programmable wakeup source.
2151 bool "OLPC XO-1 SCI extras"
2152 depends on OLPC && OLPC_XO1_PM
2157 Add support for SCI-based features of the OLPC XO-1 laptop:
2158 - EC-driven system wakeups
2162 - AC adapter status updates
2163 - Battery status updates
2165 config OLPC_XO15_SCI
2166 bool "OLPC XO-1.5 SCI extras"
2167 depends on OLPC && ACPI
2170 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2171 - EC-driven system wakeups
2172 - AC adapter status updates
2173 - Battery status updates
2176 bool "PCEngines ALIX System Support (LED setup)"
2179 This option enables system support for the PCEngines ALIX.
2180 At present this just sets up LEDs for GPIO control on
2181 ALIX2/3/6 boards. However, other system specific setup should
2184 Note: You must still enable the drivers for GPIO and LED support
2185 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2187 Note: You have to set alix.force=1 for boards with Award BIOS.
2190 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2193 This option enables system support for the Soekris Engineering net5501.
2196 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2200 This option enables system support for the Traverse Technologies GEOS.
2203 bool "Technologic Systems TS-5500 platform support"
2205 select CHECK_SIGNATURE
2209 This option enables system support for the Technologic Systems TS-5500.
2215 depends on CPU_SUP_AMD && PCI
2217 source "drivers/pcmcia/Kconfig"
2219 source "drivers/pci/hotplug/Kconfig"
2222 bool "RapidIO support"
2226 If you say Y here, the kernel will include drivers and
2227 infrastructure code to support RapidIO interconnect devices.
2229 source "drivers/rapidio/Kconfig"
2234 menu "Executable file formats / Emulations"
2236 source "fs/Kconfig.binfmt"
2238 config IA32_EMULATION
2239 bool "IA32 Emulation"
2241 select COMPAT_BINFMT_ELF
2244 Include code to run legacy 32-bit programs under a
2245 64-bit kernel. You should likely turn this on, unless you're
2246 100% sure that you don't have any 32-bit programs left.
2249 tristate "IA32 a.out support"
2250 depends on IA32_EMULATION
2252 Support old a.out binaries in the 32bit emulation.
2255 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2256 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2258 Include code to run binaries for the x32 native 32-bit ABI
2259 for 64-bit processors. An x32 process gets access to the
2260 full 64-bit register file and wide data path while leaving
2261 pointers at 32 bits for smaller memory footprint.
2263 You will need a recent binutils (2.22 or later) with
2264 elf32_x86_64 support enabled to compile a kernel with this
2269 depends on IA32_EMULATION || X86_X32
2270 select ARCH_WANT_OLD_COMPAT_IPC
2273 config COMPAT_FOR_U64_ALIGNMENT
2276 config SYSVIPC_COMPAT
2288 config HAVE_ATOMIC_IOMAP
2292 config HAVE_TEXT_POKE_SMP
2294 select STOP_MACHINE if SMP
2296 config X86_DEV_DMA_OPS
2298 depends on X86_64 || STA2X11
2300 config X86_DMA_REMAP
2304 source "net/Kconfig"
2306 source "drivers/Kconfig"
2308 source "drivers/firmware/Kconfig"
2312 source "arch/x86/Kconfig.debug"
2314 source "security/Kconfig"
2316 source "crypto/Kconfig"
2318 source "arch/x86/kvm/Kconfig"
2320 source "lib/Kconfig"