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 ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_PERF_EVENTS_NMI
61 select HAVE_ARCH_KMEMCHECK
62 select HAVE_USER_RETURN_NOTIFIER
63 select HAVE_ARCH_JUMP_LABEL
64 select HAVE_TEXT_POKE_SMP
65 select HAVE_GENERIC_HARDIRQS
66 select HAVE_SPARSE_IRQ
68 select GENERIC_FIND_FIRST_BIT
69 select GENERIC_IRQ_PROBE
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_IRQ_SHOW
72 select GENERIC_CLOCKEVENTS_MIN_ADJUST
73 select IRQ_FORCED_THREADING
74 select USE_GENERIC_SMP_HELPERS if SMP
75 select HAVE_BPF_JIT if (X86_64 && NET)
77 select ARCH_HAVE_NMI_SAFE_CMPXCHG
78 select GENERIC_CPU_VULNERABILITIES
79 select ARCH_SUPPORTS_ATOMIC_RMW
81 config INSTRUCTION_DECODER
82 def_bool (KPROBES || PERF_EVENTS)
86 default "elf32-i386" if X86_32
87 default "elf64-x86-64" if X86_64
91 default "arch/x86/configs/i386_defconfig" if X86_32
92 default "arch/x86/configs/x86_64_defconfig" if X86_64
94 config GENERIC_CMOS_UPDATE
97 config CLOCKSOURCE_WATCHDOG
100 config GENERIC_CLOCKEVENTS
103 config ARCH_CLOCKSOURCE_DATA
107 config GENERIC_CLOCKEVENTS_BROADCAST
109 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
111 config LOCKDEP_SUPPORT
114 config STACKTRACE_SUPPORT
117 config HAVE_LATENCYTOP_SUPPORT
124 bool "DMA memory allocation support" if EXPERT
127 DMA memory allocation support allows devices with less than 32-bit
128 addressing to allocate within the first 16MB of address space.
129 Disable if no such devices will be used.
136 config NEED_DMA_MAP_STATE
138 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
140 config NEED_SG_DMA_LENGTH
143 config GENERIC_ISA_DMA
152 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
154 config GENERIC_BUG_RELATIVE_POINTERS
157 config GENERIC_HWEIGHT
163 config ARCH_MAY_HAVE_PC_FDC
166 config RWSEM_GENERIC_SPINLOCK
169 config RWSEM_XCHGADD_ALGORITHM
172 config ARCH_HAS_CPU_IDLE_WAIT
175 config GENERIC_CALIBRATE_DELAY
178 config GENERIC_TIME_VSYSCALL
182 config ARCH_HAS_CPU_RELAX
185 config ARCH_HAS_DEFAULT_IDLE
188 config ARCH_HAS_CACHE_LINE_SIZE
191 config HAVE_SETUP_PER_CPU_AREA
194 config NEED_PER_CPU_EMBED_FIRST_CHUNK
197 config NEED_PER_CPU_PAGE_FIRST_CHUNK
200 config ARCH_HIBERNATION_POSSIBLE
203 config ARCH_SUSPEND_POSSIBLE
210 config ARCH_POPULATES_NODE_MAP
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
251 config ARCH_CPU_PROBE_RELEASE
253 depends on HOTPLUG_CPU
255 source "init/Kconfig"
256 source "kernel/Kconfig.freezer"
258 menu "Processor type and features"
260 source "kernel/time/Kconfig"
263 bool "Symmetric multi-processing support"
265 This enables support for systems with more than one CPU. If you have
266 a system with only one CPU, like most personal computers, say N. If
267 you have a system with more than one CPU, say Y.
269 If you say N here, the kernel will run on single and multiprocessor
270 machines, but will use only one CPU of a multiprocessor machine. If
271 you say Y here, the kernel will run on many, but not all,
272 singleprocessor machines. On a singleprocessor machine, the kernel
273 will run faster if you say N here.
275 Note that if you say Y here and choose architecture "586" or
276 "Pentium" under "Processor family", the kernel will not work on 486
277 architectures. Similarly, multiprocessor kernels for the "PPro"
278 architecture may not work on all Pentium based boards.
280 People using multiprocessor machines who say Y here should also say
281 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
282 Management" code will be disabled if you say Y here.
284 See also <file:Documentation/x86/i386/IO-APIC.txt>,
285 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
286 <http://www.tldp.org/docs.html#howto>.
288 If you don't know what to do here, say N.
291 bool "Support x2apic"
292 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
294 This enables x2apic support on CPUs that have this feature.
296 This allows 32-bit apic IDs (so it can support very large systems),
297 and accesses the local apic via MSRs not via mmio.
299 If you don't know what to do here, say N.
302 bool "Enable MPS table" if ACPI
304 depends on X86_LOCAL_APIC
306 For old smp systems that do not have proper acpi support. Newer systems
307 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
310 bool "Support for big SMP systems with more than 8 CPUs"
311 depends on X86_32 && SMP
313 This option is needed for the systems that have more than 8 CPUs
316 bool "Avoid speculative indirect branches in kernel"
319 Compile kernel with the retpoline compiler options to guard against
320 kernel-to-user data leaks by avoiding speculative indirect
321 branches. Requires a compiler with -mindirect-branch=thunk-extern
322 support for full protection. The kernel may run slower.
324 Without compiler support, at least indirect branches in assembler
325 code are eliminated. Since this includes the syscall entry path,
326 it is not entirely pointless.
329 config X86_EXTENDED_PLATFORM
330 bool "Support for extended (non-PC) x86 platforms"
333 If you disable this option then the kernel will only support
334 standard PC platforms. (which covers the vast majority of
337 If you enable this option then you'll be able to select support
338 for the following (non-PC) 32 bit x86 platforms:
342 SGI 320/540 (Visual Workstation)
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:
365 If you have one of these systems, or if you want to build a
366 generic distribution kernel, say Y here - otherwise say N.
368 # This is an alphabetically sorted list of 64 bit extended platforms
369 # Please maintain the alphabetic order if and when there are additions
373 select PARAVIRT_GUEST
375 depends on X86_64 && PCI
376 depends on X86_EXTENDED_PLATFORM
378 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
379 supposed to run on these EM64T-based machines. Only choose this option
380 if you have one of these machines.
383 bool "SGI Ultraviolet"
385 depends on X86_EXTENDED_PLATFORM
387 depends on X86_X2APIC
389 This option is needed in order to support SGI Ultraviolet systems.
390 If you don't have one of these, you should say N here.
392 # Following is an alphabetically sorted list of 32 bit extended platforms
393 # Please maintain the alphabetic order if and when there are additions
396 bool "CE4100 TV platform"
398 depends on PCI_GODIRECT
400 depends on X86_EXTENDED_PLATFORM
401 select X86_REBOOTFIXUPS
403 select OF_EARLY_FLATTREE
405 Select for the Intel CE media processor (CE4100) SOC.
406 This option compiles in support for the CE4100 SOC for settop
407 boxes and media devices.
409 config X86_WANT_INTEL_MID
410 bool "Intel MID platform support"
412 depends on X86_EXTENDED_PLATFORM
414 Select to build a kernel capable of supporting Intel MID platform
415 systems which do not have the PCI legacy interfaces (Moorestown,
416 Medfield). If you are building for a PC class system say N here.
418 if X86_WANT_INTEL_MID
424 bool "Moorestown MID platform"
427 depends on X86_IO_APIC
432 select X86_PLATFORM_DEVICES
435 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
436 Internet Device(MID) platform. Moorestown consists of two chips:
437 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
438 Unlike standard x86 PCs, Moorestown does not have many legacy devices
439 nor standard legacy replacement devices/features. e.g. Moorestown does
440 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
445 bool "RDC R-321x SoC"
447 depends on X86_EXTENDED_PLATFORM
449 select X86_REBOOTFIXUPS
451 This option is needed for RDC R-321x system-on-chip, also known
453 If you don't have one of these chips, you should say N here.
455 config X86_32_NON_STANDARD
456 bool "Support non-standard 32-bit SMP architectures"
457 depends on X86_32 && SMP
458 depends on X86_EXTENDED_PLATFORM
460 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
461 subarchitectures. It is intended for a generic binary kernel.
462 if you select them all, kernel will probe it one by one. and will
465 # Alphabetically sorted list of Non standard 32 bit platforms
468 bool "NUMAQ (IBM/Sequent)"
469 depends on X86_32_NON_STANDARD
474 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
475 NUMA multiquad box. This changes the way that processors are
476 bootstrapped, and uses Clustered Logical APIC addressing mode instead
477 of Flat Logical. You will need a new lynxer.elf file to flash your
478 firmware with - send email to <Martin.Bligh@us.ibm.com>.
480 config X86_SUPPORTS_MEMORY_FAILURE
482 # MCE code calls memory_failure():
484 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
485 depends on !X86_NUMAQ
486 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
487 depends on X86_64 || !SPARSEMEM
488 select ARCH_SUPPORTS_MEMORY_FAILURE
491 bool "SGI 320/540 (Visual Workstation)"
492 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
493 depends on X86_32_NON_STANDARD
495 The SGI Visual Workstation series is an IA32-based workstation
496 based on SGI systems chips with some legacy PC hardware attached.
498 Say Y here to create a kernel to run on the SGI 320 or 540.
500 A kernel compiled for the Visual Workstation will run on general
501 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
504 bool "Summit/EXA (IBM x440)"
505 depends on X86_32_NON_STANDARD
507 This option is needed for IBM systems that use the Summit/EXA chipset.
508 In particular, it is needed for the x440.
511 bool "Unisys ES7000 IA32 series"
512 depends on X86_32_NON_STANDARD && X86_BIGSMP
514 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
515 supposed to run on an IA32-based Unisys ES7000 system.
518 tristate "Eurobraille/Iris poweroff module"
521 The Iris machines from EuroBraille do not have APM or ACPI support
522 to shut themselves down properly. A special I/O sequence is
523 needed to do so, which is what this module does at
526 This is only for Iris machines from EuroBraille.
530 config SCHED_OMIT_FRAME_POINTER
532 prompt "Single-depth WCHAN output"
535 Calculate simpler /proc/<PID>/wchan values. If this option
536 is disabled then wchan values will recurse back to the
537 caller function. This provides more accurate wchan values,
538 at the expense of slightly more scheduling overhead.
540 If in doubt, say "Y".
542 menuconfig PARAVIRT_GUEST
543 bool "Paravirtualized guest support"
545 Say Y here to get to see options related to running Linux under
546 various hypervisors. This option alone does not add any kernel code.
548 If you say N, all options in this submenu will be skipped and disabled.
552 config PARAVIRT_TIME_ACCOUNTING
553 bool "Paravirtual steal time accounting"
557 Select this option to enable fine granularity task steal time
558 accounting. Time spent executing other tasks in parallel with
559 the current vCPU is discounted from the vCPU power. To account for
560 that, there can be a small performance impact.
562 If in doubt, say N here.
564 source "arch/x86/xen/Kconfig"
567 bool "KVM paravirtualized clock"
569 select PARAVIRT_CLOCK
571 Turning on this option will allow you to run a paravirtualized clock
572 when running over the KVM hypervisor. Instead of relying on a PIT
573 (or probably other) emulation by the underlying device model, the host
574 provides the guest with timing infrastructure such as time of day, and
578 bool "KVM Guest support"
581 This option enables various optimizations for running under the KVM
584 source "arch/x86/lguest/Kconfig"
587 bool "Enable paravirtualization code"
589 This changes the kernel so it can modify itself when it is run
590 under a hypervisor, potentially improving performance significantly
591 over full virtualization. However, when run without a hypervisor
592 the kernel is theoretically slower and slightly larger.
594 config PARAVIRT_SPINLOCKS
595 bool "Paravirtualization layer for spinlocks"
596 depends on PARAVIRT && SMP && EXPERIMENTAL
598 Paravirtualized spinlocks allow a pvops backend to replace the
599 spinlock implementation with something virtualization-friendly
600 (for example, block the virtual CPU rather than spinning).
602 Unfortunately the downside is an up to 5% performance hit on
603 native kernels, with various workloads.
605 If you are unsure how to answer this question, answer N.
607 config PARAVIRT_CLOCK
612 config PARAVIRT_DEBUG
613 bool "paravirt-ops debugging"
614 depends on PARAVIRT && DEBUG_KERNEL
616 Enable to debug paravirt_ops internals. Specifically, BUG if
617 a paravirt_op is missing when it is called.
625 This option adds a kernel parameter 'memtest', which allows memtest
627 memtest=0, mean disabled; -- default
628 memtest=1, mean do 1 test pattern;
630 memtest=4, mean do 4 test patterns.
631 If you are unsure how to answer this question, answer N.
633 config X86_SUMMIT_NUMA
635 depends on X86_32 && NUMA && X86_32_NON_STANDARD
637 config X86_CYCLONE_TIMER
639 depends on X86_32_NON_STANDARD
641 source "arch/x86/Kconfig.cpu"
645 prompt "HPET Timer Support" if X86_32
647 Use the IA-PC HPET (High Precision Event Timer) to manage
648 time in preference to the PIT and RTC, if a HPET is
650 HPET is the next generation timer replacing legacy 8254s.
651 The HPET provides a stable time base on SMP
652 systems, unlike the TSC, but it is more expensive to access,
653 as it is off-chip. You can find the HPET spec at
654 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
656 You can safely choose Y here. However, HPET will only be
657 activated if the platform and the BIOS support this feature.
658 Otherwise the 8254 will be used for timing services.
660 Choose N to continue using the legacy 8254 timer.
662 config HPET_EMULATE_RTC
664 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
668 prompt "Langwell APB Timer Support" if X86_MRST
671 APB timer is the replacement for 8254, HPET on X86 MID platforms.
672 The APBT provides a stable time base on SMP
673 systems, unlike the TSC, but it is more expensive to access,
674 as it is off-chip. APB timers are always running regardless of CPU
675 C states, they are used as per CPU clockevent device when possible.
677 # Mark as expert because too many people got it wrong.
678 # The code disables itself when not needed.
681 bool "Enable DMI scanning" if EXPERT
683 Enabled scanning of DMI to identify machine quirks. Say Y
684 here unless you have verified that your setup is not
685 affected by entries in the DMI blacklist. Required by PNP
689 bool "GART IOMMU support" if EXPERT
692 depends on X86_64 && PCI && AMD_NB
694 Support for full DMA access of devices with 32bit memory access only
695 on systems with more than 3GB. This is usually needed for USB,
696 sound, many IDE/SATA chipsets and some other devices.
697 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
698 based hardware IOMMU and a software bounce buffer based IOMMU used
699 on Intel systems and as fallback.
700 The code is only active when needed (enough memory and limited
701 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
705 bool "IBM Calgary IOMMU support"
707 depends on X86_64 && PCI && EXPERIMENTAL
709 Support for hardware IOMMUs in IBM's xSeries x366 and x460
710 systems. Needed to run systems with more than 3GB of memory
711 properly with 32-bit PCI devices that do not support DAC
712 (Double Address Cycle). Calgary also supports bus level
713 isolation, where all DMAs pass through the IOMMU. This
714 prevents them from going anywhere except their intended
715 destination. This catches hard-to-find kernel bugs and
716 mis-behaving drivers and devices that do not use the DMA-API
717 properly to set up their DMA buffers. The IOMMU can be
718 turned off at boot time with the iommu=off parameter.
719 Normally the kernel will make the right choice by itself.
722 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
724 prompt "Should Calgary be enabled by default?"
725 depends on CALGARY_IOMMU
727 Should Calgary be enabled by default? if you choose 'y', Calgary
728 will be used (if it exists). If you choose 'n', Calgary will not be
729 used even if it exists. If you choose 'n' and would like to use
730 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
733 # need this always selected by IOMMU for the VIA workaround
737 Support for software bounce buffers used on x86-64 systems
738 which don't have a hardware IOMMU (e.g. the current generation
739 of Intel's x86-64 CPUs). Using this PCI devices which can only
740 access 32-bits of memory can be used on systems with more than
741 3 GB of memory. If unsure, say Y.
744 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
747 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
748 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
749 select CPUMASK_OFFSTACK
751 Enable maximum number of CPUS and NUMA Nodes for this architecture.
755 int "Maximum number of CPUs" if SMP && !MAXSMP
756 range 2 8 if SMP && X86_32 && !X86_BIGSMP
757 range 2 512 if SMP && !MAXSMP
759 default "4096" if MAXSMP
760 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
763 This allows you to specify the maximum number of CPUs which this
764 kernel will support. The maximum supported value is 512 and the
765 minimum value which makes sense is 2.
767 This is purely to save memory - each supported CPU adds
768 approximately eight kilobytes to the kernel image.
771 bool "SMT (Hyperthreading) scheduler support"
774 SMT scheduler support improves the CPU scheduler's decision making
775 when dealing with Intel Pentium 4 chips with HyperThreading at a
776 cost of slightly increased overhead in some places. If unsure say
781 prompt "Multi-core scheduler support"
784 Multi-core scheduler support improves the CPU scheduler's decision
785 making when dealing with multi-core CPU chips at a cost of slightly
786 increased overhead in some places. If unsure say N here.
788 config IRQ_TIME_ACCOUNTING
789 bool "Fine granularity task level IRQ time accounting"
792 Select this option to enable fine granularity task irq time
793 accounting. This is done by reading a timestamp on each
794 transitions between softirq and hardirq state, so there can be a
795 small performance impact.
797 If in doubt, say N here.
799 source "kernel/Kconfig.preempt"
802 bool "Local APIC support on uniprocessors"
803 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
805 A local APIC (Advanced Programmable Interrupt Controller) is an
806 integrated interrupt controller in the CPU. If you have a single-CPU
807 system which has a processor with a local APIC, you can say Y here to
808 enable and use it. If you say Y here even though your machine doesn't
809 have a local APIC, then the kernel will still run with no slowdown at
810 all. The local APIC supports CPU-generated self-interrupts (timer,
811 performance counters), and the NMI watchdog which detects hard
815 bool "IO-APIC support on uniprocessors"
816 depends on X86_UP_APIC
818 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
819 SMP-capable replacement for PC-style interrupt controllers. Most
820 SMP systems and many recent uniprocessor systems have one.
822 If you have a single-CPU system with an IO-APIC, you can say Y here
823 to use it. If you say Y here even though your machine doesn't have
824 an IO-APIC, then the kernel will still run with no slowdown at all.
826 config X86_LOCAL_APIC
828 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
832 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
834 config X86_VISWS_APIC
836 depends on X86_32 && X86_VISWS
838 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
839 bool "Reroute for broken boot IRQs"
840 depends on X86_IO_APIC
842 This option enables a workaround that fixes a source of
843 spurious interrupts. This is recommended when threaded
844 interrupt handling is used on systems where the generation of
845 superfluous "boot interrupts" cannot be disabled.
847 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
848 entry in the chipset's IO-APIC is masked (as, e.g. the RT
849 kernel does during interrupt handling). On chipsets where this
850 boot IRQ generation cannot be disabled, this workaround keeps
851 the original IRQ line masked so that only the equivalent "boot
852 IRQ" is delivered to the CPUs. The workaround also tells the
853 kernel to set up the IRQ handler on the boot IRQ line. In this
854 way only one interrupt is delivered to the kernel. Otherwise
855 the spurious second interrupt may cause the kernel to bring
856 down (vital) interrupt lines.
858 Only affects "broken" chipsets. Interrupt sharing may be
859 increased on these systems.
862 bool "Machine Check / overheating reporting"
864 Machine Check support allows the processor to notify the
865 kernel if it detects a problem (e.g. overheating, data corruption).
866 The action the kernel takes depends on the severity of the problem,
867 ranging from warning messages to halting the machine.
871 prompt "Intel MCE features"
872 depends on X86_MCE && X86_LOCAL_APIC
874 Additional support for intel specific MCE features such as
879 prompt "AMD MCE features"
880 depends on X86_MCE && X86_LOCAL_APIC
882 Additional support for AMD specific MCE features such as
883 the DRAM Error Threshold.
885 config X86_ANCIENT_MCE
886 bool "Support for old Pentium 5 / WinChip machine checks"
887 depends on X86_32 && X86_MCE
889 Include support for machine check handling on old Pentium 5 or WinChip
890 systems. These typically need to be enabled explicitely on the command
893 config X86_MCE_THRESHOLD
894 depends on X86_MCE_AMD || X86_MCE_INTEL
897 config X86_MCE_INJECT
899 tristate "Machine check injector support"
901 Provide support for injecting machine checks for testing purposes.
902 If you don't know what a machine check is and you don't do kernel
903 QA it is safe to say n.
905 config X86_THERMAL_VECTOR
907 depends on X86_MCE_INTEL
910 bool "Enable VM86 support" if EXPERT
914 This option is required by programs like DOSEMU to run
915 16-bit real mode legacy code on x86 processors. It also may
916 be needed by software like XFree86 to initialize some video
917 cards via BIOS. Disabling this option saves about 6K.
920 bool "Enable support for 16-bit segments" if EXPERT
923 This option is required by programs like Wine to run 16-bit
924 protected mode legacy code on x86 processors. Disabling
925 this option saves about 300 bytes on i386, or around 6K text
926 plus 16K runtime memory on x86-64,
930 depends on X86_16BIT && X86_32
934 depends on X86_16BIT && X86_64
937 tristate "Toshiba Laptop support"
940 This adds a driver to safely access the System Management Mode of
941 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
942 not work on models with a Phoenix BIOS. The System Management Mode
943 is used to set the BIOS and power saving options on Toshiba portables.
945 For information on utilities to make use of this driver see the
946 Toshiba Linux utilities web site at:
947 <http://www.buzzard.org.uk/toshiba/>.
949 Say Y if you intend to run this kernel on a Toshiba portable.
953 tristate "Dell laptop support"
956 This adds a driver to safely access the System Management Mode
957 of the CPU on the Dell Inspiron 8000. The System Management Mode
958 is used to read cpu temperature and cooling fan status and to
959 control the fans on the I8K portables.
961 This driver has been tested only on the Inspiron 8000 but it may
962 also work with other Dell laptops. You can force loading on other
963 models by passing the parameter `force=1' to the module. Use at
966 For information on utilities to make use of this driver see the
967 I8K Linux utilities web site at:
968 <http://people.debian.org/~dz/i8k/>
970 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
973 config X86_REBOOTFIXUPS
974 bool "Enable X86 board specific fixups for reboot"
977 This enables chipset and/or board specific fixups to be done
978 in order to get reboot to work correctly. This is only needed on
979 some combinations of hardware and BIOS. The symptom, for which
980 this config is intended, is when reboot ends with a stalled/hung
983 Currently, the only fixup is for the Geode machines using
984 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
986 Say Y if you want to enable the fixup. Currently, it's safe to
987 enable this option even if you don't need it.
991 tristate "/dev/cpu/microcode - microcode support"
994 If you say Y here, you will be able to update the microcode on
995 certain Intel and AMD processors. The Intel support is for the
996 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
997 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
998 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
999 You will obviously need the actual microcode binary data itself
1000 which is not shipped with the Linux kernel.
1002 This option selects the general module only, you need to select
1003 at least one vendor specific module as well.
1005 To compile this driver as a module, choose M here: the
1006 module will be called microcode.
1008 config MICROCODE_INTEL
1009 bool "Intel microcode patch loading support"
1010 depends on MICROCODE
1014 This options enables microcode patch loading support for Intel
1017 For latest news and information on obtaining all the required
1018 Intel ingredients for this driver, check:
1019 <http://www.urbanmyth.org/microcode/>.
1021 config MICROCODE_AMD
1022 bool "AMD microcode patch loading support"
1023 depends on MICROCODE
1026 If you select this option, microcode patch loading support for AMD
1027 processors will be enabled.
1029 config MICROCODE_OLD_INTERFACE
1031 depends on MICROCODE
1034 tristate "/dev/cpu/*/msr - Model-specific register support"
1036 This device gives privileged processes access to the x86
1037 Model-Specific Registers (MSRs). It is a character device with
1038 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1039 MSR accesses are directed to a specific CPU on multi-processor
1043 tristate "/dev/cpu/*/cpuid - CPU information support"
1045 This device gives processes access to the x86 CPUID instruction to
1046 be executed on a specific processor. It is a character device
1047 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1051 prompt "High Memory Support"
1052 default HIGHMEM64G if X86_NUMAQ
1058 depends on !X86_NUMAQ
1060 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1061 However, the address space of 32-bit x86 processors is only 4
1062 Gigabytes large. That means that, if you have a large amount of
1063 physical memory, not all of it can be "permanently mapped" by the
1064 kernel. The physical memory that's not permanently mapped is called
1067 If you are compiling a kernel which will never run on a machine with
1068 more than 1 Gigabyte total physical RAM, answer "off" here (default
1069 choice and suitable for most users). This will result in a "3GB/1GB"
1070 split: 3GB are mapped so that each process sees a 3GB virtual memory
1071 space and the remaining part of the 4GB virtual memory space is used
1072 by the kernel to permanently map as much physical memory as
1075 If the machine has between 1 and 4 Gigabytes physical RAM, then
1078 If more than 4 Gigabytes is used then answer "64GB" here. This
1079 selection turns Intel PAE (Physical Address Extension) mode on.
1080 PAE implements 3-level paging on IA32 processors. PAE is fully
1081 supported by Linux, PAE mode is implemented on all recent Intel
1082 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1083 then the kernel will not boot on CPUs that don't support PAE!
1085 The actual amount of total physical memory will either be
1086 auto detected or can be forced by using a kernel command line option
1087 such as "mem=256M". (Try "man bootparam" or see the documentation of
1088 your boot loader (lilo or loadlin) about how to pass options to the
1089 kernel at boot time.)
1091 If unsure, say "off".
1095 depends on !X86_NUMAQ
1097 Select this if you have a 32-bit processor and between 1 and 4
1098 gigabytes of physical RAM.
1102 depends on !M386 && !M486
1105 Select this if you have a 32-bit processor and more than 4
1106 gigabytes of physical RAM.
1111 depends on EXPERIMENTAL
1112 prompt "Memory split" if EXPERT
1116 Select the desired split between kernel and user memory.
1118 If the address range available to the kernel is less than the
1119 physical memory installed, the remaining memory will be available
1120 as "high memory". Accessing high memory is a little more costly
1121 than low memory, as it needs to be mapped into the kernel first.
1122 Note that increasing the kernel address space limits the range
1123 available to user programs, making the address space there
1124 tighter. Selecting anything other than the default 3G/1G split
1125 will also likely make your kernel incompatible with binary-only
1128 If you are not absolutely sure what you are doing, leave this
1132 bool "3G/1G user/kernel split"
1133 config VMSPLIT_3G_OPT
1135 bool "3G/1G user/kernel split (for full 1G low memory)"
1137 bool "2G/2G user/kernel split"
1138 config VMSPLIT_2G_OPT
1140 bool "2G/2G user/kernel split (for full 2G low memory)"
1142 bool "1G/3G user/kernel split"
1147 default 0xB0000000 if VMSPLIT_3G_OPT
1148 default 0x80000000 if VMSPLIT_2G
1149 default 0x78000000 if VMSPLIT_2G_OPT
1150 default 0x40000000 if VMSPLIT_1G
1156 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1159 bool "PAE (Physical Address Extension) Support"
1160 depends on X86_32 && !HIGHMEM4G
1162 PAE is required for NX support, and furthermore enables
1163 larger swapspace support for non-overcommit purposes. It
1164 has the cost of more pagetable lookup overhead, and also
1165 consumes more pagetable space per process.
1167 config ARCH_PHYS_ADDR_T_64BIT
1168 def_bool X86_64 || X86_PAE
1170 config ARCH_DMA_ADDR_T_64BIT
1171 def_bool X86_64 || HIGHMEM64G
1173 config DIRECT_GBPAGES
1174 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1178 Allow the kernel linear mapping to use 1GB pages on CPUs that
1179 support it. This can improve the kernel's performance a tiny bit by
1180 reducing TLB pressure. If in doubt, say "Y".
1182 # Common NUMA Features
1184 bool "Numa Memory Allocation and Scheduler Support"
1186 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && BROKEN)
1187 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1189 Enable NUMA (Non Uniform Memory Access) support.
1191 The kernel will try to allocate memory used by a CPU on the
1192 local memory controller of the CPU and add some more
1193 NUMA awareness to the kernel.
1195 For 64-bit this is recommended if the system is Intel Core i7
1196 (or later), AMD Opteron, or EM64T NUMA.
1198 For 32-bit this is only needed on (rare) 32-bit-only platforms
1199 that support NUMA topologies, such as NUMAQ / Summit, or if you
1200 boot a 32-bit kernel on a 64-bit NUMA platform.
1202 Otherwise, you should say N.
1204 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1205 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1209 prompt "Old style AMD Opteron NUMA detection"
1210 depends on X86_64 && NUMA && PCI
1212 Enable AMD NUMA node topology detection. You should say Y here if
1213 you have a multi processor AMD system. This uses an old method to
1214 read the NUMA configuration directly from the builtin Northbridge
1215 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1216 which also takes priority if both are compiled in.
1218 config X86_64_ACPI_NUMA
1220 prompt "ACPI NUMA detection"
1221 depends on X86_64 && NUMA && ACPI && PCI
1224 Enable ACPI SRAT based node topology detection.
1226 # Some NUMA nodes have memory ranges that span
1227 # other nodes. Even though a pfn is valid and
1228 # between a node's start and end pfns, it may not
1229 # reside on that node. See memmap_init_zone()
1231 config NODES_SPAN_OTHER_NODES
1233 depends on X86_64_ACPI_NUMA
1236 bool "NUMA emulation"
1239 Enable NUMA emulation. A flat machine will be split
1240 into virtual nodes when booted with "numa=fake=N", where N is the
1241 number of nodes. This is only useful for debugging.
1244 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1246 default "10" if MAXSMP
1247 default "6" if X86_64
1248 default "4" if X86_NUMAQ
1250 depends on NEED_MULTIPLE_NODES
1252 Specify the maximum number of NUMA Nodes available on the target
1253 system. Increases memory reserved to accommodate various tables.
1255 config HAVE_ARCH_BOOTMEM
1257 depends on X86_32 && NUMA
1259 config HAVE_ARCH_ALLOC_REMAP
1261 depends on X86_32 && NUMA
1263 config ARCH_HAVE_MEMORY_PRESENT
1265 depends on X86_32 && DISCONTIGMEM
1267 config NEED_NODE_MEMMAP_SIZE
1269 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1271 config ARCH_FLATMEM_ENABLE
1273 depends on X86_32 && !NUMA
1275 config ARCH_DISCONTIGMEM_ENABLE
1277 depends on NUMA && X86_32
1279 config ARCH_DISCONTIGMEM_DEFAULT
1281 depends on NUMA && X86_32
1283 config ARCH_SPARSEMEM_ENABLE
1285 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1286 select SPARSEMEM_STATIC if X86_32
1287 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1289 config ARCH_SPARSEMEM_DEFAULT
1293 config ARCH_SELECT_MEMORY_MODEL
1295 depends on ARCH_SPARSEMEM_ENABLE
1297 config ARCH_MEMORY_PROBE
1299 depends on MEMORY_HOTPLUG
1301 config ARCH_PROC_KCORE_TEXT
1303 depends on X86_64 && PROC_KCORE
1305 config ILLEGAL_POINTER_VALUE
1308 default 0xdead000000000000 if X86_64
1313 bool "Allocate 3rd-level pagetables from highmem"
1316 The VM uses one page table entry for each page of physical memory.
1317 For systems with a lot of RAM, this can be wasteful of precious
1318 low memory. Setting this option will put user-space page table
1319 entries in high memory.
1321 config X86_CHECK_BIOS_CORRUPTION
1322 bool "Check for low memory corruption"
1324 Periodically check for memory corruption in low memory, which
1325 is suspected to be caused by BIOS. Even when enabled in the
1326 configuration, it is disabled at runtime. Enable it by
1327 setting "memory_corruption_check=1" on the kernel command
1328 line. By default it scans the low 64k of memory every 60
1329 seconds; see the memory_corruption_check_size and
1330 memory_corruption_check_period parameters in
1331 Documentation/kernel-parameters.txt to adjust this.
1333 When enabled with the default parameters, this option has
1334 almost no overhead, as it reserves a relatively small amount
1335 of memory and scans it infrequently. It both detects corruption
1336 and prevents it from affecting the running system.
1338 It is, however, intended as a diagnostic tool; if repeatable
1339 BIOS-originated corruption always affects the same memory,
1340 you can use memmap= to prevent the kernel from using that
1343 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1344 bool "Set the default setting of memory_corruption_check"
1345 depends on X86_CHECK_BIOS_CORRUPTION
1348 Set whether the default state of memory_corruption_check is
1351 config X86_RESERVE_LOW
1352 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1356 Specify the amount of low memory to reserve for the BIOS.
1358 The first page contains BIOS data structures that the kernel
1359 must not use, so that page must always be reserved.
1361 By default we reserve the first 64K of physical RAM, as a
1362 number of BIOSes are known to corrupt that memory range
1363 during events such as suspend/resume or monitor cable
1364 insertion, so it must not be used by the kernel.
1366 You can set this to 4 if you are absolutely sure that you
1367 trust the BIOS to get all its memory reservations and usages
1368 right. If you know your BIOS have problems beyond the
1369 default 64K area, you can set this to 640 to avoid using the
1370 entire low memory range.
1372 If you have doubts about the BIOS (e.g. suspend/resume does
1373 not work or there's kernel crashes after certain hardware
1374 hotplug events) then you might want to enable
1375 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1376 typical corruption patterns.
1378 Leave this to the default value of 64 if you are unsure.
1380 config MATH_EMULATION
1382 prompt "Math emulation" if X86_32
1384 Linux can emulate a math coprocessor (used for floating point
1385 operations) if you don't have one. 486DX and Pentium processors have
1386 a math coprocessor built in, 486SX and 386 do not, unless you added
1387 a 487DX or 387, respectively. (The messages during boot time can
1388 give you some hints here ["man dmesg"].) Everyone needs either a
1389 coprocessor or this emulation.
1391 If you don't have a math coprocessor, you need to say Y here; if you
1392 say Y here even though you have a coprocessor, the coprocessor will
1393 be used nevertheless. (This behavior can be changed with the kernel
1394 command line option "no387", which comes handy if your coprocessor
1395 is broken. Try "man bootparam" or see the documentation of your boot
1396 loader (lilo or loadlin) about how to pass options to the kernel at
1397 boot time.) This means that it is a good idea to say Y here if you
1398 intend to use this kernel on different machines.
1400 More information about the internals of the Linux math coprocessor
1401 emulation can be found in <file:arch/x86/math-emu/README>.
1403 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1404 kernel, it won't hurt.
1408 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1410 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1411 the Memory Type Range Registers (MTRRs) may be used to control
1412 processor access to memory ranges. This is most useful if you have
1413 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1414 allows bus write transfers to be combined into a larger transfer
1415 before bursting over the PCI/AGP bus. This can increase performance
1416 of image write operations 2.5 times or more. Saying Y here creates a
1417 /proc/mtrr file which may be used to manipulate your processor's
1418 MTRRs. Typically the X server should use this.
1420 This code has a reasonably generic interface so that similar
1421 control registers on other processors can be easily supported
1424 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1425 Registers (ARRs) which provide a similar functionality to MTRRs. For
1426 these, the ARRs are used to emulate the MTRRs.
1427 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1428 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1429 write-combining. All of these processors are supported by this code
1430 and it makes sense to say Y here if you have one of them.
1432 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1433 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1434 can lead to all sorts of problems, so it's good to say Y here.
1436 You can safely say Y even if your machine doesn't have MTRRs, you'll
1437 just add about 9 KB to your kernel.
1439 See <file:Documentation/x86/mtrr.txt> for more information.
1441 config MTRR_SANITIZER
1443 prompt "MTRR cleanup support"
1446 Convert MTRR layout from continuous to discrete, so X drivers can
1447 add writeback entries.
1449 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1450 The largest mtrr entry size for a continuous block can be set with
1455 config MTRR_SANITIZER_ENABLE_DEFAULT
1456 int "MTRR cleanup enable value (0-1)"
1459 depends on MTRR_SANITIZER
1461 Enable mtrr cleanup default value
1463 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1464 int "MTRR cleanup spare reg num (0-7)"
1467 depends on MTRR_SANITIZER
1469 mtrr cleanup spare entries default, it can be changed via
1470 mtrr_spare_reg_nr=N on the kernel command line.
1474 prompt "x86 PAT support" if EXPERT
1477 Use PAT attributes to setup page level cache control.
1479 PATs are the modern equivalents of MTRRs and are much more
1480 flexible than MTRRs.
1482 Say N here if you see bootup problems (boot crash, boot hang,
1483 spontaneous reboots) or a non-working video driver.
1487 config ARCH_USES_PG_UNCACHED
1493 prompt "x86 architectural random number generator" if EXPERT
1495 Enable the x86 architectural RDRAND instruction
1496 (Intel Bull Mountain technology) to generate random numbers.
1497 If supported, this is a high bandwidth, cryptographically
1498 secure hardware random number generator.
1501 bool "EFI runtime service support"
1504 This enables the kernel to use EFI runtime services that are
1505 available (such as the EFI variable services).
1507 This option is only useful on systems that have EFI firmware.
1508 In addition, you should use the latest ELILO loader available
1509 at <http://elilo.sourceforge.net> in order to take advantage
1510 of EFI runtime services. However, even with this option, the
1511 resultant kernel should continue to boot on existing non-EFI
1516 prompt "Enable seccomp to safely compute untrusted bytecode"
1518 This kernel feature is useful for number crunching applications
1519 that may need to compute untrusted bytecode during their
1520 execution. By using pipes or other transports made available to
1521 the process as file descriptors supporting the read/write
1522 syscalls, it's possible to isolate those applications in
1523 their own address space using seccomp. Once seccomp is
1524 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1525 and the task is only allowed to execute a few safe syscalls
1526 defined by each seccomp mode.
1528 If unsure, say Y. Only embedded should say N here.
1530 config CC_STACKPROTECTOR
1531 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1533 This option turns on the -fstack-protector GCC feature. This
1534 feature puts, at the beginning of functions, a canary value on
1535 the stack just before the return address, and validates
1536 the value just before actually returning. Stack based buffer
1537 overflows (that need to overwrite this return address) now also
1538 overwrite the canary, which gets detected and the attack is then
1539 neutralized via a kernel panic.
1541 This feature requires gcc version 4.2 or above, or a distribution
1542 gcc with the feature backported. Older versions are automatically
1543 detected and for those versions, this configuration option is
1544 ignored. (and a warning is printed during bootup)
1546 source kernel/Kconfig.hz
1549 bool "kexec system call"
1551 kexec is a system call that implements the ability to shutdown your
1552 current kernel, and to start another kernel. It is like a reboot
1553 but it is independent of the system firmware. And like a reboot
1554 you can start any kernel with it, not just Linux.
1556 The name comes from the similarity to the exec system call.
1558 It is an ongoing process to be certain the hardware in a machine
1559 is properly shutdown, so do not be surprised if this code does not
1560 initially work for you. It may help to enable device hotplugging
1561 support. As of this writing the exact hardware interface is
1562 strongly in flux, so no good recommendation can be made.
1565 bool "kernel crash dumps"
1566 depends on X86_64 || (X86_32 && HIGHMEM)
1568 Generate crash dump after being started by kexec.
1569 This should be normally only set in special crash dump kernels
1570 which are loaded in the main kernel with kexec-tools into
1571 a specially reserved region and then later executed after
1572 a crash by kdump/kexec. The crash dump kernel must be compiled
1573 to a memory address not used by the main kernel or BIOS using
1574 PHYSICAL_START, or it must be built as a relocatable image
1575 (CONFIG_RELOCATABLE=y).
1576 For more details see Documentation/kdump/kdump.txt
1579 bool "kexec jump (EXPERIMENTAL)"
1580 depends on EXPERIMENTAL
1581 depends on KEXEC && HIBERNATION
1583 Jump between original kernel and kexeced kernel and invoke
1584 code in physical address mode via KEXEC
1586 config PHYSICAL_START
1587 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1590 This gives the physical address where the kernel is loaded.
1592 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1593 bzImage will decompress itself to above physical address and
1594 run from there. Otherwise, bzImage will run from the address where
1595 it has been loaded by the boot loader and will ignore above physical
1598 In normal kdump cases one does not have to set/change this option
1599 as now bzImage can be compiled as a completely relocatable image
1600 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1601 address. This option is mainly useful for the folks who don't want
1602 to use a bzImage for capturing the crash dump and want to use a
1603 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1604 to be specifically compiled to run from a specific memory area
1605 (normally a reserved region) and this option comes handy.
1607 So if you are using bzImage for capturing the crash dump,
1608 leave the value here unchanged to 0x1000000 and set
1609 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1610 for capturing the crash dump change this value to start of
1611 the reserved region. In other words, it can be set based on
1612 the "X" value as specified in the "crashkernel=YM@XM"
1613 command line boot parameter passed to the panic-ed
1614 kernel. Please take a look at Documentation/kdump/kdump.txt
1615 for more details about crash dumps.
1617 Usage of bzImage for capturing the crash dump is recommended as
1618 one does not have to build two kernels. Same kernel can be used
1619 as production kernel and capture kernel. Above option should have
1620 gone away after relocatable bzImage support is introduced. But it
1621 is present because there are users out there who continue to use
1622 vmlinux for dump capture. This option should go away down the
1625 Don't change this unless you know what you are doing.
1628 bool "Build a relocatable kernel"
1631 This builds a kernel image that retains relocation information
1632 so it can be loaded someplace besides the default 1MB.
1633 The relocations tend to make the kernel binary about 10% larger,
1634 but are discarded at runtime.
1636 One use is for the kexec on panic case where the recovery kernel
1637 must live at a different physical address than the primary
1640 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1641 it has been loaded at and the compile time physical address
1642 (CONFIG_PHYSICAL_START) is ignored.
1644 # Relocation on x86-32 needs some additional build support
1645 config X86_NEED_RELOCS
1647 depends on X86_32 && RELOCATABLE
1649 config PHYSICAL_ALIGN
1650 hex "Alignment value to which kernel should be aligned" if X86_32
1652 range 0x2000 0x1000000
1654 This value puts the alignment restrictions on physical address
1655 where kernel is loaded and run from. Kernel is compiled for an
1656 address which meets above alignment restriction.
1658 If bootloader loads the kernel at a non-aligned address and
1659 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1660 address aligned to above value and run from there.
1662 If bootloader loads the kernel at a non-aligned address and
1663 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1664 load address and decompress itself to the address it has been
1665 compiled for and run from there. The address for which kernel is
1666 compiled already meets above alignment restrictions. Hence the
1667 end result is that kernel runs from a physical address meeting
1668 above alignment restrictions.
1670 Don't change this unless you know what you are doing.
1673 bool "Support for hot-pluggable CPUs"
1674 depends on SMP && HOTPLUG
1676 Say Y here to allow turning CPUs off and on. CPUs can be
1677 controlled through /sys/devices/system/cpu.
1678 ( Note: power management support will enable this option
1679 automatically on SMP systems. )
1680 Say N if you want to disable CPU hotplug.
1684 prompt "Compat VDSO support"
1685 depends on X86_32 || IA32_EMULATION
1687 Map the 32-bit VDSO to the predictable old-style address too.
1689 Say N here if you are running a sufficiently recent glibc
1690 version (2.3.3 or later), to remove the high-mapped
1691 VDSO mapping and to exclusively use the randomized VDSO.
1696 bool "Built-in kernel command line"
1698 Allow for specifying boot arguments to the kernel at
1699 build time. On some systems (e.g. embedded ones), it is
1700 necessary or convenient to provide some or all of the
1701 kernel boot arguments with the kernel itself (that is,
1702 to not rely on the boot loader to provide them.)
1704 To compile command line arguments into the kernel,
1705 set this option to 'Y', then fill in the
1706 the boot arguments in CONFIG_CMDLINE.
1708 Systems with fully functional boot loaders (i.e. non-embedded)
1709 should leave this option set to 'N'.
1712 string "Built-in kernel command string"
1713 depends on CMDLINE_BOOL
1716 Enter arguments here that should be compiled into the kernel
1717 image and used at boot time. If the boot loader provides a
1718 command line at boot time, it is appended to this string to
1719 form the full kernel command line, when the system boots.
1721 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1722 change this behavior.
1724 In most cases, the command line (whether built-in or provided
1725 by the boot loader) should specify the device for the root
1728 config CMDLINE_OVERRIDE
1729 bool "Built-in command line overrides boot loader arguments"
1730 depends on CMDLINE_BOOL
1732 Set this option to 'Y' to have the kernel ignore the boot loader
1733 command line, and use ONLY the built-in command line.
1735 This is used to work around broken boot loaders. This should
1736 be set to 'N' under normal conditions.
1740 config ARCH_ENABLE_MEMORY_HOTPLUG
1742 depends on X86_64 || (X86_32 && HIGHMEM)
1744 config ARCH_ENABLE_MEMORY_HOTREMOVE
1746 depends on MEMORY_HOTPLUG
1748 config USE_PERCPU_NUMA_NODE_ID
1752 menu "Power management and ACPI options"
1754 config ARCH_HIBERNATION_HEADER
1756 depends on X86_64 && HIBERNATION
1758 source "kernel/power/Kconfig"
1760 source "drivers/acpi/Kconfig"
1762 source "drivers/sfi/Kconfig"
1766 depends on APM || APM_MODULE
1769 tristate "APM (Advanced Power Management) BIOS support"
1770 depends on X86_32 && PM_SLEEP
1772 APM is a BIOS specification for saving power using several different
1773 techniques. This is mostly useful for battery powered laptops with
1774 APM compliant BIOSes. If you say Y here, the system time will be
1775 reset after a RESUME operation, the /proc/apm device will provide
1776 battery status information, and user-space programs will receive
1777 notification of APM "events" (e.g. battery status change).
1779 If you select "Y" here, you can disable actual use of the APM
1780 BIOS by passing the "apm=off" option to the kernel at boot time.
1782 Note that the APM support is almost completely disabled for
1783 machines with more than one CPU.
1785 In order to use APM, you will need supporting software. For location
1786 and more information, read <file:Documentation/power/apm-acpi.txt>
1787 and the Battery Powered Linux mini-HOWTO, available from
1788 <http://www.tldp.org/docs.html#howto>.
1790 This driver does not spin down disk drives (see the hdparm(8)
1791 manpage ("man 8 hdparm") for that), and it doesn't turn off
1792 VESA-compliant "green" monitors.
1794 This driver does not support the TI 4000M TravelMate and the ACER
1795 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1796 desktop machines also don't have compliant BIOSes, and this driver
1797 may cause those machines to panic during the boot phase.
1799 Generally, if you don't have a battery in your machine, there isn't
1800 much point in using this driver and you should say N. If you get
1801 random kernel OOPSes or reboots that don't seem to be related to
1802 anything, try disabling/enabling this option (or disabling/enabling
1805 Some other things you should try when experiencing seemingly random,
1808 1) make sure that you have enough swap space and that it is
1810 2) pass the "no-hlt" option to the kernel
1811 3) switch on floating point emulation in the kernel and pass
1812 the "no387" option to the kernel
1813 4) pass the "floppy=nodma" option to the kernel
1814 5) pass the "mem=4M" option to the kernel (thereby disabling
1815 all but the first 4 MB of RAM)
1816 6) make sure that the CPU is not over clocked.
1817 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1818 8) disable the cache from your BIOS settings
1819 9) install a fan for the video card or exchange video RAM
1820 10) install a better fan for the CPU
1821 11) exchange RAM chips
1822 12) exchange the motherboard.
1824 To compile this driver as a module, choose M here: the
1825 module will be called apm.
1829 config APM_IGNORE_USER_SUSPEND
1830 bool "Ignore USER SUSPEND"
1832 This option will ignore USER SUSPEND requests. On machines with a
1833 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1834 series notebooks, it is necessary to say Y because of a BIOS bug.
1836 config APM_DO_ENABLE
1837 bool "Enable PM at boot time"
1839 Enable APM features at boot time. From page 36 of the APM BIOS
1840 specification: "When disabled, the APM BIOS does not automatically
1841 power manage devices, enter the Standby State, enter the Suspend
1842 State, or take power saving steps in response to CPU Idle calls."
1843 This driver will make CPU Idle calls when Linux is idle (unless this
1844 feature is turned off -- see "Do CPU IDLE calls", below). This
1845 should always save battery power, but more complicated APM features
1846 will be dependent on your BIOS implementation. You may need to turn
1847 this option off if your computer hangs at boot time when using APM
1848 support, or if it beeps continuously instead of suspending. Turn
1849 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1850 T400CDT. This is off by default since most machines do fine without
1854 bool "Make CPU Idle calls when idle"
1856 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1857 On some machines, this can activate improved power savings, such as
1858 a slowed CPU clock rate, when the machine is idle. These idle calls
1859 are made after the idle loop has run for some length of time (e.g.,
1860 333 mS). On some machines, this will cause a hang at boot time or
1861 whenever the CPU becomes idle. (On machines with more than one CPU,
1862 this option does nothing.)
1864 config APM_DISPLAY_BLANK
1865 bool "Enable console blanking using APM"
1867 Enable console blanking using the APM. Some laptops can use this to
1868 turn off the LCD backlight when the screen blanker of the Linux
1869 virtual console blanks the screen. Note that this is only used by
1870 the virtual console screen blanker, and won't turn off the backlight
1871 when using the X Window system. This also doesn't have anything to
1872 do with your VESA-compliant power-saving monitor. Further, this
1873 option doesn't work for all laptops -- it might not turn off your
1874 backlight at all, or it might print a lot of errors to the console,
1875 especially if you are using gpm.
1877 config APM_ALLOW_INTS
1878 bool "Allow interrupts during APM BIOS calls"
1880 Normally we disable external interrupts while we are making calls to
1881 the APM BIOS as a measure to lessen the effects of a badly behaving
1882 BIOS implementation. The BIOS should reenable interrupts if it
1883 needs to. Unfortunately, some BIOSes do not -- especially those in
1884 many of the newer IBM Thinkpads. If you experience hangs when you
1885 suspend, try setting this to Y. Otherwise, say N.
1889 source "drivers/cpufreq/Kconfig"
1891 source "drivers/cpuidle/Kconfig"
1893 source "drivers/idle/Kconfig"
1898 menu "Bus options (PCI etc.)"
1903 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1905 Find out whether you have a PCI motherboard. PCI is the name of a
1906 bus system, i.e. the way the CPU talks to the other stuff inside
1907 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1908 VESA. If you have PCI, say Y, otherwise N.
1911 prompt "PCI access mode"
1912 depends on X86_32 && PCI
1915 On PCI systems, the BIOS can be used to detect the PCI devices and
1916 determine their configuration. However, some old PCI motherboards
1917 have BIOS bugs and may crash if this is done. Also, some embedded
1918 PCI-based systems don't have any BIOS at all. Linux can also try to
1919 detect the PCI hardware directly without using the BIOS.
1921 With this option, you can specify how Linux should detect the
1922 PCI devices. If you choose "BIOS", the BIOS will be used,
1923 if you choose "Direct", the BIOS won't be used, and if you
1924 choose "MMConfig", then PCI Express MMCONFIG will be used.
1925 If you choose "Any", the kernel will try MMCONFIG, then the
1926 direct access method and falls back to the BIOS if that doesn't
1927 work. If unsure, go with the default, which is "Any".
1932 config PCI_GOMMCONFIG
1949 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1951 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1954 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1958 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1962 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1966 depends on PCI && XEN
1974 bool "Support mmconfig PCI config space access"
1975 depends on X86_64 && PCI && ACPI
1977 config PCI_CNB20LE_QUIRK
1978 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1980 depends on PCI && EXPERIMENTAL
1982 Read the PCI windows out of the CNB20LE host bridge. This allows
1983 PCI hotplug to work on systems with the CNB20LE chipset which do
1986 There's no public spec for this chipset, and this functionality
1987 is known to be incomplete.
1989 You should say N unless you know you need this.
1991 source "drivers/pci/pcie/Kconfig"
1993 source "drivers/pci/Kconfig"
1995 # x86_64 have no ISA slots, but can have ISA-style DMA.
1997 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2000 Enables ISA-style DMA support for devices requiring such controllers.
2008 Find out whether you have ISA slots on your motherboard. ISA is the
2009 name of a bus system, i.e. the way the CPU talks to the other stuff
2010 inside your box. Other bus systems are PCI, EISA, MicroChannel
2011 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2012 newer boards don't support it. If you have ISA, say Y, otherwise N.
2018 The Extended Industry Standard Architecture (EISA) bus was
2019 developed as an open alternative to the IBM MicroChannel bus.
2021 The EISA bus provided some of the features of the IBM MicroChannel
2022 bus while maintaining backward compatibility with cards made for
2023 the older ISA bus. The EISA bus saw limited use between 1988 and
2024 1995 when it was made obsolete by the PCI bus.
2026 Say Y here if you are building a kernel for an EISA-based machine.
2030 source "drivers/eisa/Kconfig"
2035 MicroChannel Architecture is found in some IBM PS/2 machines and
2036 laptops. It is a bus system similar to PCI or ISA. See
2037 <file:Documentation/mca.txt> (and especially the web page given
2038 there) before attempting to build an MCA bus kernel.
2040 source "drivers/mca/Kconfig"
2043 tristate "NatSemi SCx200 support"
2045 This provides basic support for National Semiconductor's
2046 (now AMD's) Geode processors. The driver probes for the
2047 PCI-IDs of several on-chip devices, so its a good dependency
2048 for other scx200_* drivers.
2050 If compiled as a module, the driver is named scx200.
2052 config SCx200HR_TIMER
2053 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2057 This driver provides a clocksource built upon the on-chip
2058 27MHz high-resolution timer. Its also a workaround for
2059 NSC Geode SC-1100's buggy TSC, which loses time when the
2060 processor goes idle (as is done by the scheduler). The
2061 other workaround is idle=poll boot option.
2064 bool "One Laptop Per Child support"
2070 Add support for detecting the unique features of the OLPC
2074 bool "OLPC XO-1 Power Management"
2075 depends on OLPC && MFD_CS5535 && PM_SLEEP
2078 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2081 bool "OLPC XO-1 Real Time Clock"
2082 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2084 Add support for the XO-1 real time clock, which can be used as a
2085 programmable wakeup source.
2088 bool "OLPC XO-1 SCI extras"
2089 depends on OLPC && OLPC_XO1_PM
2094 Add support for SCI-based features of the OLPC XO-1 laptop:
2095 - EC-driven system wakeups
2099 - AC adapter status updates
2100 - Battery status updates
2102 config OLPC_XO15_SCI
2103 bool "OLPC XO-1.5 SCI extras"
2104 depends on OLPC && ACPI
2107 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2108 - EC-driven system wakeups
2109 - AC adapter status updates
2110 - Battery status updates
2113 bool "PCEngines ALIX System Support (LED setup)"
2116 This option enables system support for the PCEngines ALIX.
2117 At present this just sets up LEDs for GPIO control on
2118 ALIX2/3/6 boards. However, other system specific setup should
2121 Note: You must still enable the drivers for GPIO and LED support
2122 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2124 Note: You have to set alix.force=1 for boards with Award BIOS.
2130 depends on CPU_SUP_AMD && PCI
2132 source "drivers/pcmcia/Kconfig"
2134 source "drivers/pci/hotplug/Kconfig"
2137 bool "RapidIO support"
2141 If you say Y here, the kernel will include drivers and
2142 infrastructure code to support RapidIO interconnect devices.
2144 source "drivers/rapidio/Kconfig"
2149 menu "Executable file formats / Emulations"
2151 source "fs/Kconfig.binfmt"
2153 config IA32_EMULATION
2154 bool "IA32 Emulation"
2157 select COMPAT_BINFMT_ELF
2159 Include code to run 32-bit programs under a 64-bit kernel. You should
2160 likely turn this on, unless you're 100% sure that you don't have any
2161 32-bit programs left.
2164 tristate "IA32 a.out support"
2165 depends on IA32_EMULATION
2167 Support old a.out binaries in the 32bit emulation.
2171 depends on IA32_EMULATION
2173 config COMPAT_FOR_U64_ALIGNMENT
2177 config SYSVIPC_COMPAT
2179 depends on COMPAT && SYSVIPC
2183 depends on COMPAT && KEYS
2189 config HAVE_ATOMIC_IOMAP
2193 config HAVE_TEXT_POKE_SMP
2195 select STOP_MACHINE if SMP
2197 source "net/Kconfig"
2199 source "drivers/Kconfig"
2201 source "drivers/firmware/Kconfig"
2205 source "arch/x86/Kconfig.debug"
2207 source "security/Kconfig"
2209 source "crypto/Kconfig"
2211 source "arch/x86/kvm/Kconfig"
2213 source "lib/Kconfig"