3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select HAVE_MEMBLOCK_NODE_MAP
30 select ARCH_DISCARD_MEMBLOCK
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_C_RECORDMCOUNT
38 select HAVE_DYNAMIC_FTRACE
39 select HAVE_FUNCTION_TRACER
40 select HAVE_FUNCTION_GRAPH_TRACER
41 select HAVE_FUNCTION_GRAPH_FP_TEST
42 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
43 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
44 select HAVE_SYSCALL_TRACEPOINTS
47 select HAVE_ARCH_TRACEHOOK
48 select HAVE_GENERIC_DMA_COHERENT if X86_32
49 select HAVE_EFFICIENT_UNALIGNED_ACCESS
50 select USER_STACKTRACE_SUPPORT
51 select HAVE_REGS_AND_STACK_ACCESS_API
52 select HAVE_DMA_API_DEBUG
53 select HAVE_KERNEL_GZIP
54 select HAVE_KERNEL_BZIP2
55 select HAVE_KERNEL_LZMA
57 select HAVE_KERNEL_LZO
58 select HAVE_HW_BREAKPOINT
59 select HAVE_MIXED_BREAKPOINTS_REGS
61 select HAVE_PERF_EVENTS_NMI
63 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
64 select HAVE_CMPXCHG_LOCAL if !M386
65 select HAVE_CMPXCHG_DOUBLE
66 select HAVE_ARCH_KMEMCHECK
67 select HAVE_USER_RETURN_NOTIFIER
68 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
69 select HAVE_ARCH_JUMP_LABEL
70 select HAVE_TEXT_POKE_SMP
71 select HAVE_GENERIC_HARDIRQS
73 select GENERIC_FIND_FIRST_BIT
74 select GENERIC_IRQ_PROBE
75 select GENERIC_PENDING_IRQ if SMP
76 select GENERIC_IRQ_SHOW
77 select GENERIC_CLOCKEVENTS_MIN_ADJUST
78 select IRQ_FORCED_THREADING
79 select USE_GENERIC_SMP_HELPERS if SMP
80 select HAVE_BPF_JIT if (X86_64 && NET)
82 select ARCH_HAVE_NMI_SAFE_CMPXCHG
84 select DCACHE_WORD_ACCESS
85 select GENERIC_CMOS_UPDATE
86 select CLOCKSOURCE_WATCHDOG
87 select GENERIC_CLOCKEVENTS
88 select ARCH_CLOCKSOURCE_DATA if X86_64
89 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
90 select GENERIC_TIME_VSYSCALL if X86_64
91 select KTIME_SCALAR if X86_32
93 config INSTRUCTION_DECODER
94 def_bool (KPROBES || PERF_EVENTS)
98 default "elf32-i386" if X86_32
99 default "elf64-x86-64" if X86_64
101 config ARCH_DEFCONFIG
103 default "arch/x86/configs/i386_defconfig" if X86_32
104 default "arch/x86/configs/x86_64_defconfig" if X86_64
106 config LOCKDEP_SUPPORT
109 config STACKTRACE_SUPPORT
112 config HAVE_LATENCYTOP_SUPPORT
121 config NEED_DMA_MAP_STATE
122 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
124 config NEED_SG_DMA_LENGTH
127 config GENERIC_ISA_DMA
133 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
135 config GENERIC_BUG_RELATIVE_POINTERS
138 config GENERIC_HWEIGHT
144 config ARCH_MAY_HAVE_PC_FDC
147 config RWSEM_GENERIC_SPINLOCK
150 config RWSEM_XCHGADD_ALGORITHM
153 config ARCH_HAS_CPU_IDLE_WAIT
156 config GENERIC_CALIBRATE_DELAY
159 config ARCH_HAS_CPU_RELAX
162 config ARCH_HAS_DEFAULT_IDLE
165 config ARCH_HAS_CACHE_LINE_SIZE
168 config ARCH_HAS_CPU_AUTOPROBE
171 config HAVE_SETUP_PER_CPU_AREA
174 config NEED_PER_CPU_EMBED_FIRST_CHUNK
177 config NEED_PER_CPU_PAGE_FIRST_CHUNK
180 config ARCH_HIBERNATION_POSSIBLE
183 config ARCH_SUSPEND_POSSIBLE
194 config ARCH_SUPPORTS_OPTIMIZED_INLINING
197 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
200 config HAVE_INTEL_TXT
202 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
206 depends on X86_32 && SMP
210 depends on X86_64 && SMP
216 config X86_32_LAZY_GS
218 depends on X86_32 && !CC_STACKPROTECTOR
220 config ARCH_HWEIGHT_CFLAGS
222 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
223 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
225 config ARCH_CPU_PROBE_RELEASE
227 depends on HOTPLUG_CPU
229 source "init/Kconfig"
230 source "kernel/Kconfig.freezer"
232 menu "Processor type and features"
235 bool "DMA memory allocation support" if EXPERT
238 DMA memory allocation support allows devices with less than 32-bit
239 addressing to allocate within the first 16MB of address space.
240 Disable if no such devices will be used.
244 source "kernel/time/Kconfig"
247 bool "Symmetric multi-processing support"
249 This enables support for systems with more than one CPU. If you have
250 a system with only one CPU, like most personal computers, say N. If
251 you have a system with more than one CPU, say Y.
253 If you say N here, the kernel will run on single and multiprocessor
254 machines, but will use only one CPU of a multiprocessor machine. If
255 you say Y here, the kernel will run on many, but not all,
256 singleprocessor machines. On a singleprocessor machine, the kernel
257 will run faster if you say N here.
259 Note that if you say Y here and choose architecture "586" or
260 "Pentium" under "Processor family", the kernel will not work on 486
261 architectures. Similarly, multiprocessor kernels for the "PPro"
262 architecture may not work on all Pentium based boards.
264 People using multiprocessor machines who say Y here should also say
265 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
266 Management" code will be disabled if you say Y here.
268 See also <file:Documentation/x86/i386/IO-APIC.txt>,
269 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
270 <http://www.tldp.org/docs.html#howto>.
272 If you don't know what to do here, say N.
275 bool "Support x2apic"
276 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
278 This enables x2apic support on CPUs that have this feature.
280 This allows 32-bit apic IDs (so it can support very large systems),
281 and accesses the local apic via MSRs not via mmio.
283 If you don't know what to do here, say N.
286 bool "Enable MPS table" if ACPI
288 depends on X86_LOCAL_APIC
290 For old smp systems that do not have proper acpi support. Newer systems
291 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
294 bool "Support for big SMP systems with more than 8 CPUs"
295 depends on X86_32 && SMP
297 This option is needed for the systems that have more than 8 CPUs
300 config X86_EXTENDED_PLATFORM
301 bool "Support for extended (non-PC) x86 platforms"
304 If you disable this option then the kernel will only support
305 standard PC platforms. (which covers the vast majority of
308 If you enable this option then you'll be able to select support
309 for the following (non-PC) 32 bit x86 platforms:
313 SGI 320/540 (Visual Workstation)
314 Summit/EXA (IBM x440)
315 Unisys ES7000 IA32 series
316 Moorestown MID devices
318 If you have one of these systems, or if you want to build a
319 generic distribution kernel, say Y here - otherwise say N.
323 config X86_EXTENDED_PLATFORM
324 bool "Support for extended (non-PC) x86 platforms"
327 If you disable this option then the kernel will only support
328 standard PC platforms. (which covers the vast majority of
331 If you enable this option then you'll be able to select support
332 for the following (non-PC) 64 bit x86 platforms:
337 If you have one of these systems, or if you want to build a
338 generic distribution kernel, say Y here - otherwise say N.
340 # This is an alphabetically sorted list of 64 bit extended platforms
341 # Please maintain the alphabetic order if and when there are additions
343 bool "Numascale NumaChip"
345 depends on X86_EXTENDED_PLATFORM
348 depends on X86_X2APIC
350 Adds support for Numascale NumaChip large-SMP systems. Needed to
351 enable more than ~168 cores.
352 If you don't have one of these, you should say N here.
356 select PARAVIRT_GUEST
358 depends on X86_64 && PCI
359 depends on X86_EXTENDED_PLATFORM
361 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
362 supposed to run on these EM64T-based machines. Only choose this option
363 if you have one of these machines.
366 bool "SGI Ultraviolet"
368 depends on X86_EXTENDED_PLATFORM
370 depends on X86_X2APIC
372 This option is needed in order to support SGI Ultraviolet systems.
373 If you don't have one of these, you should say N here.
375 # Following is an alphabetically sorted list of 32 bit extended platforms
376 # Please maintain the alphabetic order if and when there are additions
379 bool "CE4100 TV platform"
381 depends on PCI_GODIRECT
383 depends on X86_EXTENDED_PLATFORM
384 select X86_REBOOTFIXUPS
386 select OF_EARLY_FLATTREE
389 Select for the Intel CE media processor (CE4100) SOC.
390 This option compiles in support for the CE4100 SOC for settop
391 boxes and media devices.
393 config X86_WANT_INTEL_MID
394 bool "Intel MID platform support"
396 depends on X86_EXTENDED_PLATFORM
398 Select to build a kernel capable of supporting Intel MID platform
399 systems which do not have the PCI legacy interfaces (Moorestown,
400 Medfield). If you are building for a PC class system say N here.
402 if X86_WANT_INTEL_MID
408 bool "Medfield MID platform"
411 depends on X86_IO_APIC
419 select X86_PLATFORM_DEVICES
420 select MFD_INTEL_MSIC
422 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
423 Internet Device(MID) platform.
424 Unlike standard x86 PCs, Medfield does not have many legacy devices
425 nor standard legacy replacement devices/features. e.g. Medfield does
426 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
431 bool "RDC R-321x SoC"
433 depends on X86_EXTENDED_PLATFORM
435 select X86_REBOOTFIXUPS
437 This option is needed for RDC R-321x system-on-chip, also known
439 If you don't have one of these chips, you should say N here.
441 config X86_32_NON_STANDARD
442 bool "Support non-standard 32-bit SMP architectures"
443 depends on X86_32 && SMP
444 depends on X86_EXTENDED_PLATFORM
446 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
447 subarchitectures. It is intended for a generic binary kernel.
448 if you select them all, kernel will probe it one by one. and will
451 # Alphabetically sorted list of Non standard 32 bit platforms
454 bool "NUMAQ (IBM/Sequent)"
455 depends on X86_32_NON_STANDARD
460 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
461 NUMA multiquad box. This changes the way that processors are
462 bootstrapped, and uses Clustered Logical APIC addressing mode instead
463 of Flat Logical. You will need a new lynxer.elf file to flash your
464 firmware with - send email to <Martin.Bligh@us.ibm.com>.
466 config X86_SUPPORTS_MEMORY_FAILURE
468 # MCE code calls memory_failure():
470 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
471 depends on !X86_NUMAQ
472 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
473 depends on X86_64 || !SPARSEMEM
474 select ARCH_SUPPORTS_MEMORY_FAILURE
477 bool "SGI 320/540 (Visual Workstation)"
478 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
479 depends on X86_32_NON_STANDARD
481 The SGI Visual Workstation series is an IA32-based workstation
482 based on SGI systems chips with some legacy PC hardware attached.
484 Say Y here to create a kernel to run on the SGI 320 or 540.
486 A kernel compiled for the Visual Workstation will run on general
487 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
490 bool "Summit/EXA (IBM x440)"
491 depends on X86_32_NON_STANDARD
493 This option is needed for IBM systems that use the Summit/EXA chipset.
494 In particular, it is needed for the x440.
497 bool "Unisys ES7000 IA32 series"
498 depends on X86_32_NON_STANDARD && X86_BIGSMP
500 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
501 supposed to run on an IA32-based Unisys ES7000 system.
504 tristate "Eurobraille/Iris poweroff module"
507 The Iris machines from EuroBraille do not have APM or ACPI support
508 to shut themselves down properly. A special I/O sequence is
509 needed to do so, which is what this module does at
512 This is only for Iris machines from EuroBraille.
516 config SCHED_OMIT_FRAME_POINTER
518 prompt "Single-depth WCHAN output"
521 Calculate simpler /proc/<PID>/wchan values. If this option
522 is disabled then wchan values will recurse back to the
523 caller function. This provides more accurate wchan values,
524 at the expense of slightly more scheduling overhead.
526 If in doubt, say "Y".
528 menuconfig PARAVIRT_GUEST
529 bool "Paravirtualized guest support"
531 Say Y here to get to see options related to running Linux under
532 various hypervisors. This option alone does not add any kernel code.
534 If you say N, all options in this submenu will be skipped and disabled.
538 config PARAVIRT_TIME_ACCOUNTING
539 bool "Paravirtual steal time accounting"
543 Select this option to enable fine granularity task steal time
544 accounting. Time spent executing other tasks in parallel with
545 the current vCPU is discounted from the vCPU power. To account for
546 that, there can be a small performance impact.
548 If in doubt, say N here.
550 source "arch/x86/xen/Kconfig"
553 bool "KVM paravirtualized clock"
555 select PARAVIRT_CLOCK
557 Turning on this option will allow you to run a paravirtualized clock
558 when running over the KVM hypervisor. Instead of relying on a PIT
559 (or probably other) emulation by the underlying device model, the host
560 provides the guest with timing infrastructure such as time of day, and
564 bool "KVM Guest support"
567 This option enables various optimizations for running under the KVM
570 source "arch/x86/lguest/Kconfig"
573 bool "Enable paravirtualization code"
575 This changes the kernel so it can modify itself when it is run
576 under a hypervisor, potentially improving performance significantly
577 over full virtualization. However, when run without a hypervisor
578 the kernel is theoretically slower and slightly larger.
580 config PARAVIRT_SPINLOCKS
581 bool "Paravirtualization layer for spinlocks"
582 depends on PARAVIRT && SMP && EXPERIMENTAL
584 Paravirtualized spinlocks allow a pvops backend to replace the
585 spinlock implementation with something virtualization-friendly
586 (for example, block the virtual CPU rather than spinning).
588 Unfortunately the downside is an up to 5% performance hit on
589 native kernels, with various workloads.
591 If you are unsure how to answer this question, answer N.
593 config PARAVIRT_CLOCK
598 config PARAVIRT_DEBUG
599 bool "paravirt-ops debugging"
600 depends on PARAVIRT && DEBUG_KERNEL
602 Enable to debug paravirt_ops internals. Specifically, BUG if
603 a paravirt_op is missing when it is called.
611 This option adds a kernel parameter 'memtest', which allows memtest
613 memtest=0, mean disabled; -- default
614 memtest=1, mean do 1 test pattern;
616 memtest=4, mean do 4 test patterns.
617 If you are unsure how to answer this question, answer N.
619 config X86_SUMMIT_NUMA
621 depends on X86_32 && NUMA && X86_32_NON_STANDARD
623 config X86_CYCLONE_TIMER
625 depends on X86_SUMMIT
627 source "arch/x86/Kconfig.cpu"
631 prompt "HPET Timer Support" if X86_32
633 Use the IA-PC HPET (High Precision Event Timer) to manage
634 time in preference to the PIT and RTC, if a HPET is
636 HPET is the next generation timer replacing legacy 8254s.
637 The HPET provides a stable time base on SMP
638 systems, unlike the TSC, but it is more expensive to access,
639 as it is off-chip. You can find the HPET spec at
640 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
642 You can safely choose Y here. However, HPET will only be
643 activated if the platform and the BIOS support this feature.
644 Otherwise the 8254 will be used for timing services.
646 Choose N to continue using the legacy 8254 timer.
648 config HPET_EMULATE_RTC
650 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
653 def_bool y if X86_INTEL_MID
654 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
656 depends on X86_INTEL_MID && SFI
658 APB timer is the replacement for 8254, HPET on X86 MID platforms.
659 The APBT provides a stable time base on SMP
660 systems, unlike the TSC, but it is more expensive to access,
661 as it is off-chip. APB timers are always running regardless of CPU
662 C states, they are used as per CPU clockevent device when possible.
664 # Mark as expert because too many people got it wrong.
665 # The code disables itself when not needed.
668 bool "Enable DMI scanning" if EXPERT
670 Enabled scanning of DMI to identify machine quirks. Say Y
671 here unless you have verified that your setup is not
672 affected by entries in the DMI blacklist. Required by PNP
676 bool "GART IOMMU support" if EXPERT
679 depends on X86_64 && PCI && AMD_NB
681 Support for full DMA access of devices with 32bit memory access only
682 on systems with more than 3GB. This is usually needed for USB,
683 sound, many IDE/SATA chipsets and some other devices.
684 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
685 based hardware IOMMU and a software bounce buffer based IOMMU used
686 on Intel systems and as fallback.
687 The code is only active when needed (enough memory and limited
688 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
692 bool "IBM Calgary IOMMU support"
694 depends on X86_64 && PCI && EXPERIMENTAL
696 Support for hardware IOMMUs in IBM's xSeries x366 and x460
697 systems. Needed to run systems with more than 3GB of memory
698 properly with 32-bit PCI devices that do not support DAC
699 (Double Address Cycle). Calgary also supports bus level
700 isolation, where all DMAs pass through the IOMMU. This
701 prevents them from going anywhere except their intended
702 destination. This catches hard-to-find kernel bugs and
703 mis-behaving drivers and devices that do not use the DMA-API
704 properly to set up their DMA buffers. The IOMMU can be
705 turned off at boot time with the iommu=off parameter.
706 Normally the kernel will make the right choice by itself.
709 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
711 prompt "Should Calgary be enabled by default?"
712 depends on CALGARY_IOMMU
714 Should Calgary be enabled by default? if you choose 'y', Calgary
715 will be used (if it exists). If you choose 'n', Calgary will not be
716 used even if it exists. If you choose 'n' and would like to use
717 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
720 # need this always selected by IOMMU for the VIA workaround
724 Support for software bounce buffers used on x86-64 systems
725 which don't have a hardware IOMMU (e.g. the current generation
726 of Intel's x86-64 CPUs). Using this PCI devices which can only
727 access 32-bits of memory can be used on systems with more than
728 3 GB of memory. If unsure, say Y.
731 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
734 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
735 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
736 select CPUMASK_OFFSTACK
738 Enable maximum number of CPUS and NUMA Nodes for this architecture.
742 int "Maximum number of CPUs" if SMP && !MAXSMP
743 range 2 8 if SMP && X86_32 && !X86_BIGSMP
744 range 2 512 if SMP && !MAXSMP
746 default "4096" if MAXSMP
747 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
750 This allows you to specify the maximum number of CPUs which this
751 kernel will support. The maximum supported value is 512 and the
752 minimum value which makes sense is 2.
754 This is purely to save memory - each supported CPU adds
755 approximately eight kilobytes to the kernel image.
758 bool "SMT (Hyperthreading) scheduler support"
761 SMT scheduler support improves the CPU scheduler's decision making
762 when dealing with Intel Pentium 4 chips with HyperThreading at a
763 cost of slightly increased overhead in some places. If unsure say
768 prompt "Multi-core scheduler support"
771 Multi-core scheduler support improves the CPU scheduler's decision
772 making when dealing with multi-core CPU chips at a cost of slightly
773 increased overhead in some places. If unsure say N here.
775 config IRQ_TIME_ACCOUNTING
776 bool "Fine granularity task level IRQ time accounting"
779 Select this option to enable fine granularity task irq time
780 accounting. This is done by reading a timestamp on each
781 transitions between softirq and hardirq state, so there can be a
782 small performance impact.
784 If in doubt, say N here.
786 source "kernel/Kconfig.preempt"
789 bool "Local APIC support on uniprocessors"
790 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
792 A local APIC (Advanced Programmable Interrupt Controller) is an
793 integrated interrupt controller in the CPU. If you have a single-CPU
794 system which has a processor with a local APIC, you can say Y here to
795 enable and use it. If you say Y here even though your machine doesn't
796 have a local APIC, then the kernel will still run with no slowdown at
797 all. The local APIC supports CPU-generated self-interrupts (timer,
798 performance counters), and the NMI watchdog which detects hard
802 bool "IO-APIC support on uniprocessors"
803 depends on X86_UP_APIC
805 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
806 SMP-capable replacement for PC-style interrupt controllers. Most
807 SMP systems and many recent uniprocessor systems have one.
809 If you have a single-CPU system with an IO-APIC, you can say Y here
810 to use it. If you say Y here even though your machine doesn't have
811 an IO-APIC, then the kernel will still run with no slowdown at all.
813 config X86_LOCAL_APIC
815 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
819 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
821 config X86_VISWS_APIC
823 depends on X86_32 && X86_VISWS
825 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
826 bool "Reroute for broken boot IRQs"
827 depends on X86_IO_APIC
829 This option enables a workaround that fixes a source of
830 spurious interrupts. This is recommended when threaded
831 interrupt handling is used on systems where the generation of
832 superfluous "boot interrupts" cannot be disabled.
834 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
835 entry in the chipset's IO-APIC is masked (as, e.g. the RT
836 kernel does during interrupt handling). On chipsets where this
837 boot IRQ generation cannot be disabled, this workaround keeps
838 the original IRQ line masked so that only the equivalent "boot
839 IRQ" is delivered to the CPUs. The workaround also tells the
840 kernel to set up the IRQ handler on the boot IRQ line. In this
841 way only one interrupt is delivered to the kernel. Otherwise
842 the spurious second interrupt may cause the kernel to bring
843 down (vital) interrupt lines.
845 Only affects "broken" chipsets. Interrupt sharing may be
846 increased on these systems.
849 bool "Machine Check / overheating reporting"
851 Machine Check support allows the processor to notify the
852 kernel if it detects a problem (e.g. overheating, data corruption).
853 The action the kernel takes depends on the severity of the problem,
854 ranging from warning messages to halting the machine.
858 prompt "Intel MCE features"
859 depends on X86_MCE && X86_LOCAL_APIC
861 Additional support for intel specific MCE features such as
866 prompt "AMD MCE features"
867 depends on X86_MCE && X86_LOCAL_APIC
869 Additional support for AMD specific MCE features such as
870 the DRAM Error Threshold.
872 config X86_ANCIENT_MCE
873 bool "Support for old Pentium 5 / WinChip machine checks"
874 depends on X86_32 && X86_MCE
876 Include support for machine check handling on old Pentium 5 or WinChip
877 systems. These typically need to be enabled explicitely on the command
880 config X86_MCE_THRESHOLD
881 depends on X86_MCE_AMD || X86_MCE_INTEL
884 config X86_MCE_INJECT
886 tristate "Machine check injector support"
888 Provide support for injecting machine checks for testing purposes.
889 If you don't know what a machine check is and you don't do kernel
890 QA it is safe to say n.
892 config X86_THERMAL_VECTOR
894 depends on X86_MCE_INTEL
897 bool "Enable VM86 support" if EXPERT
901 This option is required by programs like DOSEMU to run 16-bit legacy
902 code on X86 processors. It also may be needed by software like
903 XFree86 to initialize some video cards via BIOS. Disabling this
904 option saves about 6k.
907 tristate "Toshiba Laptop support"
910 This adds a driver to safely access the System Management Mode of
911 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
912 not work on models with a Phoenix BIOS. The System Management Mode
913 is used to set the BIOS and power saving options on Toshiba portables.
915 For information on utilities to make use of this driver see the
916 Toshiba Linux utilities web site at:
917 <http://www.buzzard.org.uk/toshiba/>.
919 Say Y if you intend to run this kernel on a Toshiba portable.
923 tristate "Dell laptop support"
926 This adds a driver to safely access the System Management Mode
927 of the CPU on the Dell Inspiron 8000. The System Management Mode
928 is used to read cpu temperature and cooling fan status and to
929 control the fans on the I8K portables.
931 This driver has been tested only on the Inspiron 8000 but it may
932 also work with other Dell laptops. You can force loading on other
933 models by passing the parameter `force=1' to the module. Use at
936 For information on utilities to make use of this driver see the
937 I8K Linux utilities web site at:
938 <http://people.debian.org/~dz/i8k/>
940 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
943 config X86_REBOOTFIXUPS
944 bool "Enable X86 board specific fixups for reboot"
947 This enables chipset and/or board specific fixups to be done
948 in order to get reboot to work correctly. This is only needed on
949 some combinations of hardware and BIOS. The symptom, for which
950 this config is intended, is when reboot ends with a stalled/hung
953 Currently, the only fixup is for the Geode machines using
954 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
956 Say Y if you want to enable the fixup. Currently, it's safe to
957 enable this option even if you don't need it.
961 tristate "/dev/cpu/microcode - microcode support"
964 If you say Y here, you will be able to update the microcode on
965 certain Intel and AMD processors. The Intel support is for the
966 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
967 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
968 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
969 You will obviously need the actual microcode binary data itself
970 which is not shipped with the Linux kernel.
972 This option selects the general module only, you need to select
973 at least one vendor specific module as well.
975 To compile this driver as a module, choose M here: the
976 module will be called microcode.
978 config MICROCODE_INTEL
979 bool "Intel microcode patch loading support"
984 This options enables microcode patch loading support for Intel
987 For latest news and information on obtaining all the required
988 Intel ingredients for this driver, check:
989 <http://www.urbanmyth.org/microcode/>.
992 bool "AMD microcode patch loading support"
996 If you select this option, microcode patch loading support for AMD
997 processors will be enabled.
999 config MICROCODE_OLD_INTERFACE
1001 depends on MICROCODE
1004 tristate "/dev/cpu/*/msr - Model-specific register support"
1006 This device gives privileged processes access to the x86
1007 Model-Specific Registers (MSRs). It is a character device with
1008 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1009 MSR accesses are directed to a specific CPU on multi-processor
1013 tristate "/dev/cpu/*/cpuid - CPU information support"
1015 This device gives processes access to the x86 CPUID instruction to
1016 be executed on a specific processor. It is a character device
1017 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1021 prompt "High Memory Support"
1022 default HIGHMEM64G if X86_NUMAQ
1028 depends on !X86_NUMAQ
1030 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1031 However, the address space of 32-bit x86 processors is only 4
1032 Gigabytes large. That means that, if you have a large amount of
1033 physical memory, not all of it can be "permanently mapped" by the
1034 kernel. The physical memory that's not permanently mapped is called
1037 If you are compiling a kernel which will never run on a machine with
1038 more than 1 Gigabyte total physical RAM, answer "off" here (default
1039 choice and suitable for most users). This will result in a "3GB/1GB"
1040 split: 3GB are mapped so that each process sees a 3GB virtual memory
1041 space and the remaining part of the 4GB virtual memory space is used
1042 by the kernel to permanently map as much physical memory as
1045 If the machine has between 1 and 4 Gigabytes physical RAM, then
1048 If more than 4 Gigabytes is used then answer "64GB" here. This
1049 selection turns Intel PAE (Physical Address Extension) mode on.
1050 PAE implements 3-level paging on IA32 processors. PAE is fully
1051 supported by Linux, PAE mode is implemented on all recent Intel
1052 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1053 then the kernel will not boot on CPUs that don't support PAE!
1055 The actual amount of total physical memory will either be
1056 auto detected or can be forced by using a kernel command line option
1057 such as "mem=256M". (Try "man bootparam" or see the documentation of
1058 your boot loader (lilo or loadlin) about how to pass options to the
1059 kernel at boot time.)
1061 If unsure, say "off".
1065 depends on !X86_NUMAQ
1067 Select this if you have a 32-bit processor and between 1 and 4
1068 gigabytes of physical RAM.
1072 depends on !M386 && !M486
1075 Select this if you have a 32-bit processor and more than 4
1076 gigabytes of physical RAM.
1081 depends on EXPERIMENTAL
1082 prompt "Memory split" if EXPERT
1086 Select the desired split between kernel and user memory.
1088 If the address range available to the kernel is less than the
1089 physical memory installed, the remaining memory will be available
1090 as "high memory". Accessing high memory is a little more costly
1091 than low memory, as it needs to be mapped into the kernel first.
1092 Note that increasing the kernel address space limits the range
1093 available to user programs, making the address space there
1094 tighter. Selecting anything other than the default 3G/1G split
1095 will also likely make your kernel incompatible with binary-only
1098 If you are not absolutely sure what you are doing, leave this
1102 bool "3G/1G user/kernel split"
1103 config VMSPLIT_3G_OPT
1105 bool "3G/1G user/kernel split (for full 1G low memory)"
1107 bool "2G/2G user/kernel split"
1108 config VMSPLIT_2G_OPT
1110 bool "2G/2G user/kernel split (for full 2G low memory)"
1112 bool "1G/3G user/kernel split"
1117 default 0xB0000000 if VMSPLIT_3G_OPT
1118 default 0x80000000 if VMSPLIT_2G
1119 default 0x78000000 if VMSPLIT_2G_OPT
1120 default 0x40000000 if VMSPLIT_1G
1126 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1129 bool "PAE (Physical Address Extension) Support"
1130 depends on X86_32 && !HIGHMEM4G
1132 PAE is required for NX support, and furthermore enables
1133 larger swapspace support for non-overcommit purposes. It
1134 has the cost of more pagetable lookup overhead, and also
1135 consumes more pagetable space per process.
1137 config ARCH_PHYS_ADDR_T_64BIT
1138 def_bool X86_64 || X86_PAE
1140 config ARCH_DMA_ADDR_T_64BIT
1141 def_bool X86_64 || HIGHMEM64G
1143 config DIRECT_GBPAGES
1144 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1148 Allow the kernel linear mapping to use 1GB pages on CPUs that
1149 support it. This can improve the kernel's performance a tiny bit by
1150 reducing TLB pressure. If in doubt, say "Y".
1152 # Common NUMA Features
1154 bool "Numa Memory Allocation and Scheduler Support"
1156 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1157 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1159 Enable NUMA (Non Uniform Memory Access) support.
1161 The kernel will try to allocate memory used by a CPU on the
1162 local memory controller of the CPU and add some more
1163 NUMA awareness to the kernel.
1165 For 64-bit this is recommended if the system is Intel Core i7
1166 (or later), AMD Opteron, or EM64T NUMA.
1168 For 32-bit this is only needed on (rare) 32-bit-only platforms
1169 that support NUMA topologies, such as NUMAQ / Summit, or if you
1170 boot a 32-bit kernel on a 64-bit NUMA platform.
1172 Otherwise, you should say N.
1174 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1175 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1179 prompt "Old style AMD Opteron NUMA detection"
1180 depends on X86_64 && NUMA && PCI
1182 Enable AMD NUMA node topology detection. You should say Y here if
1183 you have a multi processor AMD system. This uses an old method to
1184 read the NUMA configuration directly from the builtin Northbridge
1185 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1186 which also takes priority if both are compiled in.
1188 config X86_64_ACPI_NUMA
1190 prompt "ACPI NUMA detection"
1191 depends on X86_64 && NUMA && ACPI && PCI
1194 Enable ACPI SRAT based node topology detection.
1196 # Some NUMA nodes have memory ranges that span
1197 # other nodes. Even though a pfn is valid and
1198 # between a node's start and end pfns, it may not
1199 # reside on that node. See memmap_init_zone()
1201 config NODES_SPAN_OTHER_NODES
1203 depends on X86_64_ACPI_NUMA
1206 bool "NUMA emulation"
1209 Enable NUMA emulation. A flat machine will be split
1210 into virtual nodes when booted with "numa=fake=N", where N is the
1211 number of nodes. This is only useful for debugging.
1214 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1216 default "10" if MAXSMP
1217 default "6" if X86_64
1218 default "4" if X86_NUMAQ
1220 depends on NEED_MULTIPLE_NODES
1222 Specify the maximum number of NUMA Nodes available on the target
1223 system. Increases memory reserved to accommodate various tables.
1225 config HAVE_ARCH_BOOTMEM
1227 depends on X86_32 && NUMA
1229 config HAVE_ARCH_ALLOC_REMAP
1231 depends on X86_32 && NUMA
1233 config ARCH_HAVE_MEMORY_PRESENT
1235 depends on X86_32 && DISCONTIGMEM
1237 config NEED_NODE_MEMMAP_SIZE
1239 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1241 config ARCH_FLATMEM_ENABLE
1243 depends on X86_32 && !NUMA
1245 config ARCH_DISCONTIGMEM_ENABLE
1247 depends on NUMA && X86_32
1249 config ARCH_DISCONTIGMEM_DEFAULT
1251 depends on NUMA && X86_32
1253 config ARCH_SPARSEMEM_ENABLE
1255 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1256 select SPARSEMEM_STATIC if X86_32
1257 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1259 config ARCH_SPARSEMEM_DEFAULT
1263 config ARCH_SELECT_MEMORY_MODEL
1265 depends on ARCH_SPARSEMEM_ENABLE
1267 config ARCH_MEMORY_PROBE
1269 depends on MEMORY_HOTPLUG
1271 config ARCH_PROC_KCORE_TEXT
1273 depends on X86_64 && PROC_KCORE
1275 config ILLEGAL_POINTER_VALUE
1278 default 0xdead000000000000 if X86_64
1283 bool "Allocate 3rd-level pagetables from highmem"
1286 The VM uses one page table entry for each page of physical memory.
1287 For systems with a lot of RAM, this can be wasteful of precious
1288 low memory. Setting this option will put user-space page table
1289 entries in high memory.
1291 config X86_CHECK_BIOS_CORRUPTION
1292 bool "Check for low memory corruption"
1294 Periodically check for memory corruption in low memory, which
1295 is suspected to be caused by BIOS. Even when enabled in the
1296 configuration, it is disabled at runtime. Enable it by
1297 setting "memory_corruption_check=1" on the kernel command
1298 line. By default it scans the low 64k of memory every 60
1299 seconds; see the memory_corruption_check_size and
1300 memory_corruption_check_period parameters in
1301 Documentation/kernel-parameters.txt to adjust this.
1303 When enabled with the default parameters, this option has
1304 almost no overhead, as it reserves a relatively small amount
1305 of memory and scans it infrequently. It both detects corruption
1306 and prevents it from affecting the running system.
1308 It is, however, intended as a diagnostic tool; if repeatable
1309 BIOS-originated corruption always affects the same memory,
1310 you can use memmap= to prevent the kernel from using that
1313 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1314 bool "Set the default setting of memory_corruption_check"
1315 depends on X86_CHECK_BIOS_CORRUPTION
1318 Set whether the default state of memory_corruption_check is
1321 config X86_RESERVE_LOW
1322 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1326 Specify the amount of low memory to reserve for the BIOS.
1328 The first page contains BIOS data structures that the kernel
1329 must not use, so that page must always be reserved.
1331 By default we reserve the first 64K of physical RAM, as a
1332 number of BIOSes are known to corrupt that memory range
1333 during events such as suspend/resume or monitor cable
1334 insertion, so it must not be used by the kernel.
1336 You can set this to 4 if you are absolutely sure that you
1337 trust the BIOS to get all its memory reservations and usages
1338 right. If you know your BIOS have problems beyond the
1339 default 64K area, you can set this to 640 to avoid using the
1340 entire low memory range.
1342 If you have doubts about the BIOS (e.g. suspend/resume does
1343 not work or there's kernel crashes after certain hardware
1344 hotplug events) then you might want to enable
1345 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1346 typical corruption patterns.
1348 Leave this to the default value of 64 if you are unsure.
1350 config MATH_EMULATION
1352 prompt "Math emulation" if X86_32
1354 Linux can emulate a math coprocessor (used for floating point
1355 operations) if you don't have one. 486DX and Pentium processors have
1356 a math coprocessor built in, 486SX and 386 do not, unless you added
1357 a 487DX or 387, respectively. (The messages during boot time can
1358 give you some hints here ["man dmesg"].) Everyone needs either a
1359 coprocessor or this emulation.
1361 If you don't have a math coprocessor, you need to say Y here; if you
1362 say Y here even though you have a coprocessor, the coprocessor will
1363 be used nevertheless. (This behavior can be changed with the kernel
1364 command line option "no387", which comes handy if your coprocessor
1365 is broken. Try "man bootparam" or see the documentation of your boot
1366 loader (lilo or loadlin) about how to pass options to the kernel at
1367 boot time.) This means that it is a good idea to say Y here if you
1368 intend to use this kernel on different machines.
1370 More information about the internals of the Linux math coprocessor
1371 emulation can be found in <file:arch/x86/math-emu/README>.
1373 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1374 kernel, it won't hurt.
1378 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1380 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1381 the Memory Type Range Registers (MTRRs) may be used to control
1382 processor access to memory ranges. This is most useful if you have
1383 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1384 allows bus write transfers to be combined into a larger transfer
1385 before bursting over the PCI/AGP bus. This can increase performance
1386 of image write operations 2.5 times or more. Saying Y here creates a
1387 /proc/mtrr file which may be used to manipulate your processor's
1388 MTRRs. Typically the X server should use this.
1390 This code has a reasonably generic interface so that similar
1391 control registers on other processors can be easily supported
1394 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1395 Registers (ARRs) which provide a similar functionality to MTRRs. For
1396 these, the ARRs are used to emulate the MTRRs.
1397 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1398 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1399 write-combining. All of these processors are supported by this code
1400 and it makes sense to say Y here if you have one of them.
1402 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1403 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1404 can lead to all sorts of problems, so it's good to say Y here.
1406 You can safely say Y even if your machine doesn't have MTRRs, you'll
1407 just add about 9 KB to your kernel.
1409 See <file:Documentation/x86/mtrr.txt> for more information.
1411 config MTRR_SANITIZER
1413 prompt "MTRR cleanup support"
1416 Convert MTRR layout from continuous to discrete, so X drivers can
1417 add writeback entries.
1419 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1420 The largest mtrr entry size for a continuous block can be set with
1425 config MTRR_SANITIZER_ENABLE_DEFAULT
1426 int "MTRR cleanup enable value (0-1)"
1429 depends on MTRR_SANITIZER
1431 Enable mtrr cleanup default value
1433 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1434 int "MTRR cleanup spare reg num (0-7)"
1437 depends on MTRR_SANITIZER
1439 mtrr cleanup spare entries default, it can be changed via
1440 mtrr_spare_reg_nr=N on the kernel command line.
1444 prompt "x86 PAT support" if EXPERT
1447 Use PAT attributes to setup page level cache control.
1449 PATs are the modern equivalents of MTRRs and are much more
1450 flexible than MTRRs.
1452 Say N here if you see bootup problems (boot crash, boot hang,
1453 spontaneous reboots) or a non-working video driver.
1457 config ARCH_USES_PG_UNCACHED
1463 prompt "x86 architectural random number generator" if EXPERT
1465 Enable the x86 architectural RDRAND instruction
1466 (Intel Bull Mountain technology) to generate random numbers.
1467 If supported, this is a high bandwidth, cryptographically
1468 secure hardware random number generator.
1471 bool "EFI runtime service support"
1474 This enables the kernel to use EFI runtime services that are
1475 available (such as the EFI variable services).
1477 This option is only useful on systems that have EFI firmware.
1478 In addition, you should use the latest ELILO loader available
1479 at <http://elilo.sourceforge.net> in order to take advantage
1480 of EFI runtime services. However, even with this option, the
1481 resultant kernel should continue to boot on existing non-EFI
1485 bool "EFI stub support"
1488 This kernel feature allows a bzImage to be loaded directly
1489 by EFI firmware without the use of a bootloader.
1493 prompt "Enable seccomp to safely compute untrusted bytecode"
1495 This kernel feature is useful for number crunching applications
1496 that may need to compute untrusted bytecode during their
1497 execution. By using pipes or other transports made available to
1498 the process as file descriptors supporting the read/write
1499 syscalls, it's possible to isolate those applications in
1500 their own address space using seccomp. Once seccomp is
1501 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1502 and the task is only allowed to execute a few safe syscalls
1503 defined by each seccomp mode.
1505 If unsure, say Y. Only embedded should say N here.
1507 config CC_STACKPROTECTOR
1508 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1510 This option turns on the -fstack-protector GCC feature. This
1511 feature puts, at the beginning of functions, a canary value on
1512 the stack just before the return address, and validates
1513 the value just before actually returning. Stack based buffer
1514 overflows (that need to overwrite this return address) now also
1515 overwrite the canary, which gets detected and the attack is then
1516 neutralized via a kernel panic.
1518 This feature requires gcc version 4.2 or above, or a distribution
1519 gcc with the feature backported. Older versions are automatically
1520 detected and for those versions, this configuration option is
1521 ignored. (and a warning is printed during bootup)
1523 source kernel/Kconfig.hz
1526 bool "kexec system call"
1528 kexec is a system call that implements the ability to shutdown your
1529 current kernel, and to start another kernel. It is like a reboot
1530 but it is independent of the system firmware. And like a reboot
1531 you can start any kernel with it, not just Linux.
1533 The name comes from the similarity to the exec system call.
1535 It is an ongoing process to be certain the hardware in a machine
1536 is properly shutdown, so do not be surprised if this code does not
1537 initially work for you. It may help to enable device hotplugging
1538 support. As of this writing the exact hardware interface is
1539 strongly in flux, so no good recommendation can be made.
1542 bool "kernel crash dumps"
1543 depends on X86_64 || (X86_32 && HIGHMEM)
1545 Generate crash dump after being started by kexec.
1546 This should be normally only set in special crash dump kernels
1547 which are loaded in the main kernel with kexec-tools into
1548 a specially reserved region and then later executed after
1549 a crash by kdump/kexec. The crash dump kernel must be compiled
1550 to a memory address not used by the main kernel or BIOS using
1551 PHYSICAL_START, or it must be built as a relocatable image
1552 (CONFIG_RELOCATABLE=y).
1553 For more details see Documentation/kdump/kdump.txt
1556 bool "kexec jump (EXPERIMENTAL)"
1557 depends on EXPERIMENTAL
1558 depends on KEXEC && HIBERNATION
1560 Jump between original kernel and kexeced kernel and invoke
1561 code in physical address mode via KEXEC
1563 config PHYSICAL_START
1564 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1567 This gives the physical address where the kernel is loaded.
1569 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1570 bzImage will decompress itself to above physical address and
1571 run from there. Otherwise, bzImage will run from the address where
1572 it has been loaded by the boot loader and will ignore above physical
1575 In normal kdump cases one does not have to set/change this option
1576 as now bzImage can be compiled as a completely relocatable image
1577 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1578 address. This option is mainly useful for the folks who don't want
1579 to use a bzImage for capturing the crash dump and want to use a
1580 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1581 to be specifically compiled to run from a specific memory area
1582 (normally a reserved region) and this option comes handy.
1584 So if you are using bzImage for capturing the crash dump,
1585 leave the value here unchanged to 0x1000000 and set
1586 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1587 for capturing the crash dump change this value to start of
1588 the reserved region. In other words, it can be set based on
1589 the "X" value as specified in the "crashkernel=YM@XM"
1590 command line boot parameter passed to the panic-ed
1591 kernel. Please take a look at Documentation/kdump/kdump.txt
1592 for more details about crash dumps.
1594 Usage of bzImage for capturing the crash dump is recommended as
1595 one does not have to build two kernels. Same kernel can be used
1596 as production kernel and capture kernel. Above option should have
1597 gone away after relocatable bzImage support is introduced. But it
1598 is present because there are users out there who continue to use
1599 vmlinux for dump capture. This option should go away down the
1602 Don't change this unless you know what you are doing.
1605 bool "Build a relocatable kernel"
1608 This builds a kernel image that retains relocation information
1609 so it can be loaded someplace besides the default 1MB.
1610 The relocations tend to make the kernel binary about 10% larger,
1611 but are discarded at runtime.
1613 One use is for the kexec on panic case where the recovery kernel
1614 must live at a different physical address than the primary
1617 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1618 it has been loaded at and the compile time physical address
1619 (CONFIG_PHYSICAL_START) is ignored.
1621 # Relocation on x86-32 needs some additional build support
1622 config X86_NEED_RELOCS
1624 depends on X86_32 && RELOCATABLE
1626 config PHYSICAL_ALIGN
1627 hex "Alignment value to which kernel should be aligned" if X86_32
1629 range 0x2000 0x1000000
1631 This value puts the alignment restrictions on physical address
1632 where kernel is loaded and run from. Kernel is compiled for an
1633 address which meets above alignment restriction.
1635 If bootloader loads the kernel at a non-aligned address and
1636 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1637 address aligned to above value and run from there.
1639 If bootloader loads the kernel at a non-aligned address and
1640 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1641 load address and decompress itself to the address it has been
1642 compiled for and run from there. The address for which kernel is
1643 compiled already meets above alignment restrictions. Hence the
1644 end result is that kernel runs from a physical address meeting
1645 above alignment restrictions.
1647 Don't change this unless you know what you are doing.
1650 bool "Support for hot-pluggable CPUs"
1651 depends on SMP && HOTPLUG
1653 Say Y here to allow turning CPUs off and on. CPUs can be
1654 controlled through /sys/devices/system/cpu.
1655 ( Note: power management support will enable this option
1656 automatically on SMP systems. )
1657 Say N if you want to disable CPU hotplug.
1661 prompt "Compat VDSO support"
1662 depends on X86_32 || IA32_EMULATION
1664 Map the 32-bit VDSO to the predictable old-style address too.
1666 Say N here if you are running a sufficiently recent glibc
1667 version (2.3.3 or later), to remove the high-mapped
1668 VDSO mapping and to exclusively use the randomized VDSO.
1673 bool "Built-in kernel command line"
1675 Allow for specifying boot arguments to the kernel at
1676 build time. On some systems (e.g. embedded ones), it is
1677 necessary or convenient to provide some or all of the
1678 kernel boot arguments with the kernel itself (that is,
1679 to not rely on the boot loader to provide them.)
1681 To compile command line arguments into the kernel,
1682 set this option to 'Y', then fill in the
1683 the boot arguments in CONFIG_CMDLINE.
1685 Systems with fully functional boot loaders (i.e. non-embedded)
1686 should leave this option set to 'N'.
1689 string "Built-in kernel command string"
1690 depends on CMDLINE_BOOL
1693 Enter arguments here that should be compiled into the kernel
1694 image and used at boot time. If the boot loader provides a
1695 command line at boot time, it is appended to this string to
1696 form the full kernel command line, when the system boots.
1698 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1699 change this behavior.
1701 In most cases, the command line (whether built-in or provided
1702 by the boot loader) should specify the device for the root
1705 config CMDLINE_OVERRIDE
1706 bool "Built-in command line overrides boot loader arguments"
1707 depends on CMDLINE_BOOL
1709 Set this option to 'Y' to have the kernel ignore the boot loader
1710 command line, and use ONLY the built-in command line.
1712 This is used to work around broken boot loaders. This should
1713 be set to 'N' under normal conditions.
1717 config ARCH_ENABLE_MEMORY_HOTPLUG
1719 depends on X86_64 || (X86_32 && HIGHMEM)
1721 config ARCH_ENABLE_MEMORY_HOTREMOVE
1723 depends on MEMORY_HOTPLUG
1725 config USE_PERCPU_NUMA_NODE_ID
1729 menu "Power management and ACPI options"
1731 config ARCH_HIBERNATION_HEADER
1733 depends on X86_64 && HIBERNATION
1735 source "kernel/power/Kconfig"
1737 source "drivers/acpi/Kconfig"
1739 source "drivers/sfi/Kconfig"
1746 tristate "APM (Advanced Power Management) BIOS support"
1747 depends on X86_32 && PM_SLEEP
1749 APM is a BIOS specification for saving power using several different
1750 techniques. This is mostly useful for battery powered laptops with
1751 APM compliant BIOSes. If you say Y here, the system time will be
1752 reset after a RESUME operation, the /proc/apm device will provide
1753 battery status information, and user-space programs will receive
1754 notification of APM "events" (e.g. battery status change).
1756 If you select "Y" here, you can disable actual use of the APM
1757 BIOS by passing the "apm=off" option to the kernel at boot time.
1759 Note that the APM support is almost completely disabled for
1760 machines with more than one CPU.
1762 In order to use APM, you will need supporting software. For location
1763 and more information, read <file:Documentation/power/apm-acpi.txt>
1764 and the Battery Powered Linux mini-HOWTO, available from
1765 <http://www.tldp.org/docs.html#howto>.
1767 This driver does not spin down disk drives (see the hdparm(8)
1768 manpage ("man 8 hdparm") for that), and it doesn't turn off
1769 VESA-compliant "green" monitors.
1771 This driver does not support the TI 4000M TravelMate and the ACER
1772 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1773 desktop machines also don't have compliant BIOSes, and this driver
1774 may cause those machines to panic during the boot phase.
1776 Generally, if you don't have a battery in your machine, there isn't
1777 much point in using this driver and you should say N. If you get
1778 random kernel OOPSes or reboots that don't seem to be related to
1779 anything, try disabling/enabling this option (or disabling/enabling
1782 Some other things you should try when experiencing seemingly random,
1785 1) make sure that you have enough swap space and that it is
1787 2) pass the "no-hlt" option to the kernel
1788 3) switch on floating point emulation in the kernel and pass
1789 the "no387" option to the kernel
1790 4) pass the "floppy=nodma" option to the kernel
1791 5) pass the "mem=4M" option to the kernel (thereby disabling
1792 all but the first 4 MB of RAM)
1793 6) make sure that the CPU is not over clocked.
1794 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1795 8) disable the cache from your BIOS settings
1796 9) install a fan for the video card or exchange video RAM
1797 10) install a better fan for the CPU
1798 11) exchange RAM chips
1799 12) exchange the motherboard.
1801 To compile this driver as a module, choose M here: the
1802 module will be called apm.
1806 config APM_IGNORE_USER_SUSPEND
1807 bool "Ignore USER SUSPEND"
1809 This option will ignore USER SUSPEND requests. On machines with a
1810 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1811 series notebooks, it is necessary to say Y because of a BIOS bug.
1813 config APM_DO_ENABLE
1814 bool "Enable PM at boot time"
1816 Enable APM features at boot time. From page 36 of the APM BIOS
1817 specification: "When disabled, the APM BIOS does not automatically
1818 power manage devices, enter the Standby State, enter the Suspend
1819 State, or take power saving steps in response to CPU Idle calls."
1820 This driver will make CPU Idle calls when Linux is idle (unless this
1821 feature is turned off -- see "Do CPU IDLE calls", below). This
1822 should always save battery power, but more complicated APM features
1823 will be dependent on your BIOS implementation. You may need to turn
1824 this option off if your computer hangs at boot time when using APM
1825 support, or if it beeps continuously instead of suspending. Turn
1826 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1827 T400CDT. This is off by default since most machines do fine without
1831 bool "Make CPU Idle calls when idle"
1833 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1834 On some machines, this can activate improved power savings, such as
1835 a slowed CPU clock rate, when the machine is idle. These idle calls
1836 are made after the idle loop has run for some length of time (e.g.,
1837 333 mS). On some machines, this will cause a hang at boot time or
1838 whenever the CPU becomes idle. (On machines with more than one CPU,
1839 this option does nothing.)
1841 config APM_DISPLAY_BLANK
1842 bool "Enable console blanking using APM"
1844 Enable console blanking using the APM. Some laptops can use this to
1845 turn off the LCD backlight when the screen blanker of the Linux
1846 virtual console blanks the screen. Note that this is only used by
1847 the virtual console screen blanker, and won't turn off the backlight
1848 when using the X Window system. This also doesn't have anything to
1849 do with your VESA-compliant power-saving monitor. Further, this
1850 option doesn't work for all laptops -- it might not turn off your
1851 backlight at all, or it might print a lot of errors to the console,
1852 especially if you are using gpm.
1854 config APM_ALLOW_INTS
1855 bool "Allow interrupts during APM BIOS calls"
1857 Normally we disable external interrupts while we are making calls to
1858 the APM BIOS as a measure to lessen the effects of a badly behaving
1859 BIOS implementation. The BIOS should reenable interrupts if it
1860 needs to. Unfortunately, some BIOSes do not -- especially those in
1861 many of the newer IBM Thinkpads. If you experience hangs when you
1862 suspend, try setting this to Y. Otherwise, say N.
1866 source "drivers/cpufreq/Kconfig"
1868 source "drivers/cpuidle/Kconfig"
1870 source "drivers/idle/Kconfig"
1875 menu "Bus options (PCI etc.)"
1880 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1882 Find out whether you have a PCI motherboard. PCI is the name of a
1883 bus system, i.e. the way the CPU talks to the other stuff inside
1884 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1885 VESA. If you have PCI, say Y, otherwise N.
1888 prompt "PCI access mode"
1889 depends on X86_32 && PCI
1892 On PCI systems, the BIOS can be used to detect the PCI devices and
1893 determine their configuration. However, some old PCI motherboards
1894 have BIOS bugs and may crash if this is done. Also, some embedded
1895 PCI-based systems don't have any BIOS at all. Linux can also try to
1896 detect the PCI hardware directly without using the BIOS.
1898 With this option, you can specify how Linux should detect the
1899 PCI devices. If you choose "BIOS", the BIOS will be used,
1900 if you choose "Direct", the BIOS won't be used, and if you
1901 choose "MMConfig", then PCI Express MMCONFIG will be used.
1902 If you choose "Any", the kernel will try MMCONFIG, then the
1903 direct access method and falls back to the BIOS if that doesn't
1904 work. If unsure, go with the default, which is "Any".
1909 config PCI_GOMMCONFIG
1926 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1928 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1931 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1935 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1939 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1943 depends on PCI && XEN
1951 bool "Support mmconfig PCI config space access"
1952 depends on X86_64 && PCI && ACPI
1954 config PCI_CNB20LE_QUIRK
1955 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1957 depends on PCI && EXPERIMENTAL
1959 Read the PCI windows out of the CNB20LE host bridge. This allows
1960 PCI hotplug to work on systems with the CNB20LE chipset which do
1963 There's no public spec for this chipset, and this functionality
1964 is known to be incomplete.
1966 You should say N unless you know you need this.
1968 source "drivers/pci/pcie/Kconfig"
1970 source "drivers/pci/Kconfig"
1972 # x86_64 have no ISA slots, but can have ISA-style DMA.
1974 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1977 Enables ISA-style DMA support for devices requiring such controllers.
1985 Find out whether you have ISA slots on your motherboard. ISA is the
1986 name of a bus system, i.e. the way the CPU talks to the other stuff
1987 inside your box. Other bus systems are PCI, EISA, MicroChannel
1988 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1989 newer boards don't support it. If you have ISA, say Y, otherwise N.
1995 The Extended Industry Standard Architecture (EISA) bus was
1996 developed as an open alternative to the IBM MicroChannel bus.
1998 The EISA bus provided some of the features of the IBM MicroChannel
1999 bus while maintaining backward compatibility with cards made for
2000 the older ISA bus. The EISA bus saw limited use between 1988 and
2001 1995 when it was made obsolete by the PCI bus.
2003 Say Y here if you are building a kernel for an EISA-based machine.
2007 source "drivers/eisa/Kconfig"
2012 MicroChannel Architecture is found in some IBM PS/2 machines and
2013 laptops. It is a bus system similar to PCI or ISA. See
2014 <file:Documentation/mca.txt> (and especially the web page given
2015 there) before attempting to build an MCA bus kernel.
2017 source "drivers/mca/Kconfig"
2020 tristate "NatSemi SCx200 support"
2022 This provides basic support for National Semiconductor's
2023 (now AMD's) Geode processors. The driver probes for the
2024 PCI-IDs of several on-chip devices, so its a good dependency
2025 for other scx200_* drivers.
2027 If compiled as a module, the driver is named scx200.
2029 config SCx200HR_TIMER
2030 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2034 This driver provides a clocksource built upon the on-chip
2035 27MHz high-resolution timer. Its also a workaround for
2036 NSC Geode SC-1100's buggy TSC, which loses time when the
2037 processor goes idle (as is done by the scheduler). The
2038 other workaround is idle=poll boot option.
2041 bool "One Laptop Per Child support"
2048 Add support for detecting the unique features of the OLPC
2052 bool "OLPC XO-1 Power Management"
2053 depends on OLPC && MFD_CS5535 && PM_SLEEP
2056 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2059 bool "OLPC XO-1 Real Time Clock"
2060 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2062 Add support for the XO-1 real time clock, which can be used as a
2063 programmable wakeup source.
2066 bool "OLPC XO-1 SCI extras"
2067 depends on OLPC && OLPC_XO1_PM
2072 Add support for SCI-based features of the OLPC XO-1 laptop:
2073 - EC-driven system wakeups
2077 - AC adapter status updates
2078 - Battery status updates
2080 config OLPC_XO15_SCI
2081 bool "OLPC XO-1.5 SCI extras"
2082 depends on OLPC && ACPI
2085 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2086 - EC-driven system wakeups
2087 - AC adapter status updates
2088 - Battery status updates
2091 bool "PCEngines ALIX System Support (LED setup)"
2094 This option enables system support for the PCEngines ALIX.
2095 At present this just sets up LEDs for GPIO control on
2096 ALIX2/3/6 boards. However, other system specific setup should
2099 Note: You must still enable the drivers for GPIO and LED support
2100 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2102 Note: You have to set alix.force=1 for boards with Award BIOS.
2105 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2108 This option enables system support for the Soekris Engineering net5501.
2111 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2115 This option enables system support for the Traverse Technologies GEOS.
2121 depends on CPU_SUP_AMD && PCI
2123 source "drivers/pcmcia/Kconfig"
2125 source "drivers/pci/hotplug/Kconfig"
2128 bool "RapidIO support"
2132 If you say Y here, the kernel will include drivers and
2133 infrastructure code to support RapidIO interconnect devices.
2135 source "drivers/rapidio/Kconfig"
2140 menu "Executable file formats / Emulations"
2142 source "fs/Kconfig.binfmt"
2144 config IA32_EMULATION
2145 bool "IA32 Emulation"
2147 select COMPAT_BINFMT_ELF
2149 Include code to run legacy 32-bit programs under a
2150 64-bit kernel. You should likely turn this on, unless you're
2151 100% sure that you don't have any 32-bit programs left.
2154 tristate "IA32 a.out support"
2155 depends on IA32_EMULATION
2157 Support old a.out binaries in the 32bit emulation.
2160 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2161 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2163 Include code to run binaries for the x32 native 32-bit ABI
2164 for 64-bit processors. An x32 process gets access to the
2165 full 64-bit register file and wide data path while leaving
2166 pointers at 32 bits for smaller memory footprint.
2168 You will need a recent binutils (2.22 or later) with
2169 elf32_x86_64 support enabled to compile a kernel with this
2174 depends on IA32_EMULATION || X86_X32
2175 select ARCH_WANT_OLD_COMPAT_IPC
2177 config COMPAT_FOR_U64_ALIGNMENT
2181 config SYSVIPC_COMPAT
2183 depends on COMPAT && SYSVIPC
2187 depends on COMPAT && KEYS
2193 config HAVE_ATOMIC_IOMAP
2197 config HAVE_TEXT_POKE_SMP
2199 select STOP_MACHINE if SMP
2201 source "net/Kconfig"
2203 source "drivers/Kconfig"
2205 source "drivers/firmware/Kconfig"
2209 source "arch/x86/Kconfig.debug"
2211 source "security/Kconfig"
2213 source "crypto/Kconfig"
2215 source "arch/x86/kvm/Kconfig"
2217 source "lib/Kconfig"