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.
245 bool "Symmetric multi-processing support"
247 This enables support for systems with more than one CPU. If you have
248 a system with only one CPU, like most personal computers, say N. If
249 you have a system with more than one CPU, say Y.
251 If you say N here, the kernel will run on single and multiprocessor
252 machines, but will use only one CPU of a multiprocessor machine. If
253 you say Y here, the kernel will run on many, but not all,
254 singleprocessor machines. On a singleprocessor machine, the kernel
255 will run faster if you say N here.
257 Note that if you say Y here and choose architecture "586" or
258 "Pentium" under "Processor family", the kernel will not work on 486
259 architectures. Similarly, multiprocessor kernels for the "PPro"
260 architecture may not work on all Pentium based boards.
262 People using multiprocessor machines who say Y here should also say
263 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
264 Management" code will be disabled if you say Y here.
266 See also <file:Documentation/x86/i386/IO-APIC.txt>,
267 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
268 <http://www.tldp.org/docs.html#howto>.
270 If you don't know what to do here, say N.
273 bool "Support x2apic"
274 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
276 This enables x2apic support on CPUs that have this feature.
278 This allows 32-bit apic IDs (so it can support very large systems),
279 and accesses the local apic via MSRs not via mmio.
281 If you don't know what to do here, say N.
284 bool "Enable MPS table" if ACPI
286 depends on X86_LOCAL_APIC
288 For old smp systems that do not have proper acpi support. Newer systems
289 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
292 bool "Support for big SMP systems with more than 8 CPUs"
293 depends on X86_32 && SMP
295 This option is needed for the systems that have more than 8 CPUs
298 config X86_EXTENDED_PLATFORM
299 bool "Support for extended (non-PC) x86 platforms"
302 If you disable this option then the kernel will only support
303 standard PC platforms. (which covers the vast majority of
306 If you enable this option then you'll be able to select support
307 for the following (non-PC) 32 bit x86 platforms:
311 SGI 320/540 (Visual Workstation)
312 Summit/EXA (IBM x440)
313 Unisys ES7000 IA32 series
314 Moorestown MID devices
316 If you have one of these systems, or if you want to build a
317 generic distribution kernel, say Y here - otherwise say N.
321 config X86_EXTENDED_PLATFORM
322 bool "Support for extended (non-PC) x86 platforms"
325 If you disable this option then the kernel will only support
326 standard PC platforms. (which covers the vast majority of
329 If you enable this option then you'll be able to select support
330 for the following (non-PC) 64 bit x86 platforms:
335 If you have one of these systems, or if you want to build a
336 generic distribution kernel, say Y here - otherwise say N.
338 # This is an alphabetically sorted list of 64 bit extended platforms
339 # Please maintain the alphabetic order if and when there are additions
341 bool "Numascale NumaChip"
343 depends on X86_EXTENDED_PLATFORM
346 depends on X86_X2APIC
348 Adds support for Numascale NumaChip large-SMP systems. Needed to
349 enable more than ~168 cores.
350 If you don't have one of these, you should say N here.
354 select PARAVIRT_GUEST
356 depends on X86_64 && PCI
357 depends on X86_EXTENDED_PLATFORM
359 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
360 supposed to run on these EM64T-based machines. Only choose this option
361 if you have one of these machines.
364 bool "SGI Ultraviolet"
366 depends on X86_EXTENDED_PLATFORM
368 depends on X86_X2APIC
370 This option is needed in order to support SGI Ultraviolet systems.
371 If you don't have one of these, you should say N here.
373 # Following is an alphabetically sorted list of 32 bit extended platforms
374 # Please maintain the alphabetic order if and when there are additions
377 bool "CE4100 TV platform"
379 depends on PCI_GODIRECT
381 depends on X86_EXTENDED_PLATFORM
382 select X86_REBOOTFIXUPS
384 select OF_EARLY_FLATTREE
387 Select for the Intel CE media processor (CE4100) SOC.
388 This option compiles in support for the CE4100 SOC for settop
389 boxes and media devices.
391 config X86_WANT_INTEL_MID
392 bool "Intel MID platform support"
394 depends on X86_EXTENDED_PLATFORM
396 Select to build a kernel capable of supporting Intel MID platform
397 systems which do not have the PCI legacy interfaces (Moorestown,
398 Medfield). If you are building for a PC class system say N here.
400 if X86_WANT_INTEL_MID
406 bool "Medfield MID platform"
409 depends on X86_IO_APIC
417 select X86_PLATFORM_DEVICES
418 select MFD_INTEL_MSIC
420 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
421 Internet Device(MID) platform.
422 Unlike standard x86 PCs, Medfield does not have many legacy devices
423 nor standard legacy replacement devices/features. e.g. Medfield does
424 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
429 bool "RDC R-321x SoC"
431 depends on X86_EXTENDED_PLATFORM
433 select X86_REBOOTFIXUPS
435 This option is needed for RDC R-321x system-on-chip, also known
437 If you don't have one of these chips, you should say N here.
439 config X86_32_NON_STANDARD
440 bool "Support non-standard 32-bit SMP architectures"
441 depends on X86_32 && SMP
442 depends on X86_EXTENDED_PLATFORM
444 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
445 subarchitectures. It is intended for a generic binary kernel.
446 if you select them all, kernel will probe it one by one. and will
449 # Alphabetically sorted list of Non standard 32 bit platforms
452 bool "NUMAQ (IBM/Sequent)"
453 depends on X86_32_NON_STANDARD
458 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
459 NUMA multiquad box. This changes the way that processors are
460 bootstrapped, and uses Clustered Logical APIC addressing mode instead
461 of Flat Logical. You will need a new lynxer.elf file to flash your
462 firmware with - send email to <Martin.Bligh@us.ibm.com>.
464 config X86_SUPPORTS_MEMORY_FAILURE
466 # MCE code calls memory_failure():
468 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
469 depends on !X86_NUMAQ
470 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
471 depends on X86_64 || !SPARSEMEM
472 select ARCH_SUPPORTS_MEMORY_FAILURE
475 bool "SGI 320/540 (Visual Workstation)"
476 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
477 depends on X86_32_NON_STANDARD
479 The SGI Visual Workstation series is an IA32-based workstation
480 based on SGI systems chips with some legacy PC hardware attached.
482 Say Y here to create a kernel to run on the SGI 320 or 540.
484 A kernel compiled for the Visual Workstation will run on general
485 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
488 bool "Summit/EXA (IBM x440)"
489 depends on X86_32_NON_STANDARD
491 This option is needed for IBM systems that use the Summit/EXA chipset.
492 In particular, it is needed for the x440.
495 bool "Unisys ES7000 IA32 series"
496 depends on X86_32_NON_STANDARD && X86_BIGSMP
498 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
499 supposed to run on an IA32-based Unisys ES7000 system.
502 tristate "Eurobraille/Iris poweroff module"
505 The Iris machines from EuroBraille do not have APM or ACPI support
506 to shut themselves down properly. A special I/O sequence is
507 needed to do so, which is what this module does at
510 This is only for Iris machines from EuroBraille.
514 config SCHED_OMIT_FRAME_POINTER
516 prompt "Single-depth WCHAN output"
519 Calculate simpler /proc/<PID>/wchan values. If this option
520 is disabled then wchan values will recurse back to the
521 caller function. This provides more accurate wchan values,
522 at the expense of slightly more scheduling overhead.
524 If in doubt, say "Y".
526 menuconfig PARAVIRT_GUEST
527 bool "Paravirtualized guest support"
529 Say Y here to get to see options related to running Linux under
530 various hypervisors. This option alone does not add any kernel code.
532 If you say N, all options in this submenu will be skipped and disabled.
536 config PARAVIRT_TIME_ACCOUNTING
537 bool "Paravirtual steal time accounting"
541 Select this option to enable fine granularity task steal time
542 accounting. Time spent executing other tasks in parallel with
543 the current vCPU is discounted from the vCPU power. To account for
544 that, there can be a small performance impact.
546 If in doubt, say N here.
548 source "arch/x86/xen/Kconfig"
551 bool "KVM paravirtualized clock"
553 select PARAVIRT_CLOCK
555 Turning on this option will allow you to run a paravirtualized clock
556 when running over the KVM hypervisor. Instead of relying on a PIT
557 (or probably other) emulation by the underlying device model, the host
558 provides the guest with timing infrastructure such as time of day, and
562 bool "KVM Guest support"
565 This option enables various optimizations for running under the KVM
568 source "arch/x86/lguest/Kconfig"
571 bool "Enable paravirtualization code"
573 This changes the kernel so it can modify itself when it is run
574 under a hypervisor, potentially improving performance significantly
575 over full virtualization. However, when run without a hypervisor
576 the kernel is theoretically slower and slightly larger.
578 config PARAVIRT_SPINLOCKS
579 bool "Paravirtualization layer for spinlocks"
580 depends on PARAVIRT && SMP && EXPERIMENTAL
582 Paravirtualized spinlocks allow a pvops backend to replace the
583 spinlock implementation with something virtualization-friendly
584 (for example, block the virtual CPU rather than spinning).
586 Unfortunately the downside is an up to 5% performance hit on
587 native kernels, with various workloads.
589 If you are unsure how to answer this question, answer N.
591 config PARAVIRT_CLOCK
596 config PARAVIRT_DEBUG
597 bool "paravirt-ops debugging"
598 depends on PARAVIRT && DEBUG_KERNEL
600 Enable to debug paravirt_ops internals. Specifically, BUG if
601 a paravirt_op is missing when it is called.
609 This option adds a kernel parameter 'memtest', which allows memtest
611 memtest=0, mean disabled; -- default
612 memtest=1, mean do 1 test pattern;
614 memtest=4, mean do 4 test patterns.
615 If you are unsure how to answer this question, answer N.
617 config X86_SUMMIT_NUMA
619 depends on X86_32 && NUMA && X86_32_NON_STANDARD
621 config X86_CYCLONE_TIMER
623 depends on X86_SUMMIT
625 source "arch/x86/Kconfig.cpu"
629 prompt "HPET Timer Support" if X86_32
631 Use the IA-PC HPET (High Precision Event Timer) to manage
632 time in preference to the PIT and RTC, if a HPET is
634 HPET is the next generation timer replacing legacy 8254s.
635 The HPET provides a stable time base on SMP
636 systems, unlike the TSC, but it is more expensive to access,
637 as it is off-chip. You can find the HPET spec at
638 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
640 You can safely choose Y here. However, HPET will only be
641 activated if the platform and the BIOS support this feature.
642 Otherwise the 8254 will be used for timing services.
644 Choose N to continue using the legacy 8254 timer.
646 config HPET_EMULATE_RTC
648 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
651 def_bool y if X86_INTEL_MID
652 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
654 depends on X86_INTEL_MID && SFI
656 APB timer is the replacement for 8254, HPET on X86 MID platforms.
657 The APBT provides a stable time base on SMP
658 systems, unlike the TSC, but it is more expensive to access,
659 as it is off-chip. APB timers are always running regardless of CPU
660 C states, they are used as per CPU clockevent device when possible.
662 # Mark as expert because too many people got it wrong.
663 # The code disables itself when not needed.
666 bool "Enable DMI scanning" if EXPERT
668 Enabled scanning of DMI to identify machine quirks. Say Y
669 here unless you have verified that your setup is not
670 affected by entries in the DMI blacklist. Required by PNP
674 bool "GART IOMMU support" if EXPERT
677 depends on X86_64 && PCI && AMD_NB
679 Support for full DMA access of devices with 32bit memory access only
680 on systems with more than 3GB. This is usually needed for USB,
681 sound, many IDE/SATA chipsets and some other devices.
682 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
683 based hardware IOMMU and a software bounce buffer based IOMMU used
684 on Intel systems and as fallback.
685 The code is only active when needed (enough memory and limited
686 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
690 bool "IBM Calgary IOMMU support"
692 depends on X86_64 && PCI && EXPERIMENTAL
694 Support for hardware IOMMUs in IBM's xSeries x366 and x460
695 systems. Needed to run systems with more than 3GB of memory
696 properly with 32-bit PCI devices that do not support DAC
697 (Double Address Cycle). Calgary also supports bus level
698 isolation, where all DMAs pass through the IOMMU. This
699 prevents them from going anywhere except their intended
700 destination. This catches hard-to-find kernel bugs and
701 mis-behaving drivers and devices that do not use the DMA-API
702 properly to set up their DMA buffers. The IOMMU can be
703 turned off at boot time with the iommu=off parameter.
704 Normally the kernel will make the right choice by itself.
707 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
709 prompt "Should Calgary be enabled by default?"
710 depends on CALGARY_IOMMU
712 Should Calgary be enabled by default? if you choose 'y', Calgary
713 will be used (if it exists). If you choose 'n', Calgary will not be
714 used even if it exists. If you choose 'n' and would like to use
715 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
718 # need this always selected by IOMMU for the VIA workaround
722 Support for software bounce buffers used on x86-64 systems
723 which don't have a hardware IOMMU (e.g. the current generation
724 of Intel's x86-64 CPUs). Using this PCI devices which can only
725 access 32-bits of memory can be used on systems with more than
726 3 GB of memory. If unsure, say Y.
729 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
732 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
733 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
734 select CPUMASK_OFFSTACK
736 Enable maximum number of CPUS and NUMA Nodes for this architecture.
740 int "Maximum number of CPUs" if SMP && !MAXSMP
741 range 2 8 if SMP && X86_32 && !X86_BIGSMP
742 range 2 512 if SMP && !MAXSMP
744 default "4096" if MAXSMP
745 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
748 This allows you to specify the maximum number of CPUs which this
749 kernel will support. The maximum supported value is 512 and the
750 minimum value which makes sense is 2.
752 This is purely to save memory - each supported CPU adds
753 approximately eight kilobytes to the kernel image.
756 bool "SMT (Hyperthreading) scheduler support"
759 SMT scheduler support improves the CPU scheduler's decision making
760 when dealing with Intel Pentium 4 chips with HyperThreading at a
761 cost of slightly increased overhead in some places. If unsure say
766 prompt "Multi-core scheduler support"
769 Multi-core scheduler support improves the CPU scheduler's decision
770 making when dealing with multi-core CPU chips at a cost of slightly
771 increased overhead in some places. If unsure say N here.
773 config IRQ_TIME_ACCOUNTING
774 bool "Fine granularity task level IRQ time accounting"
777 Select this option to enable fine granularity task irq time
778 accounting. This is done by reading a timestamp on each
779 transitions between softirq and hardirq state, so there can be a
780 small performance impact.
782 If in doubt, say N here.
784 source "kernel/Kconfig.preempt"
787 bool "Local APIC support on uniprocessors"
788 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
790 A local APIC (Advanced Programmable Interrupt Controller) is an
791 integrated interrupt controller in the CPU. If you have a single-CPU
792 system which has a processor with a local APIC, you can say Y here to
793 enable and use it. If you say Y here even though your machine doesn't
794 have a local APIC, then the kernel will still run with no slowdown at
795 all. The local APIC supports CPU-generated self-interrupts (timer,
796 performance counters), and the NMI watchdog which detects hard
800 bool "IO-APIC support on uniprocessors"
801 depends on X86_UP_APIC
803 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
804 SMP-capable replacement for PC-style interrupt controllers. Most
805 SMP systems and many recent uniprocessor systems have one.
807 If you have a single-CPU system with an IO-APIC, you can say Y here
808 to use it. If you say Y here even though your machine doesn't have
809 an IO-APIC, then the kernel will still run with no slowdown at all.
811 config X86_LOCAL_APIC
813 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
817 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
819 config X86_VISWS_APIC
821 depends on X86_32 && X86_VISWS
823 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
824 bool "Reroute for broken boot IRQs"
825 depends on X86_IO_APIC
827 This option enables a workaround that fixes a source of
828 spurious interrupts. This is recommended when threaded
829 interrupt handling is used on systems where the generation of
830 superfluous "boot interrupts" cannot be disabled.
832 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
833 entry in the chipset's IO-APIC is masked (as, e.g. the RT
834 kernel does during interrupt handling). On chipsets where this
835 boot IRQ generation cannot be disabled, this workaround keeps
836 the original IRQ line masked so that only the equivalent "boot
837 IRQ" is delivered to the CPUs. The workaround also tells the
838 kernel to set up the IRQ handler on the boot IRQ line. In this
839 way only one interrupt is delivered to the kernel. Otherwise
840 the spurious second interrupt may cause the kernel to bring
841 down (vital) interrupt lines.
843 Only affects "broken" chipsets. Interrupt sharing may be
844 increased on these systems.
847 bool "Machine Check / overheating reporting"
849 Machine Check support allows the processor to notify the
850 kernel if it detects a problem (e.g. overheating, data corruption).
851 The action the kernel takes depends on the severity of the problem,
852 ranging from warning messages to halting the machine.
856 prompt "Intel MCE features"
857 depends on X86_MCE && X86_LOCAL_APIC
859 Additional support for intel specific MCE features such as
864 prompt "AMD MCE features"
865 depends on X86_MCE && X86_LOCAL_APIC
867 Additional support for AMD specific MCE features such as
868 the DRAM Error Threshold.
870 config X86_ANCIENT_MCE
871 bool "Support for old Pentium 5 / WinChip machine checks"
872 depends on X86_32 && X86_MCE
874 Include support for machine check handling on old Pentium 5 or WinChip
875 systems. These typically need to be enabled explicitely on the command
878 config X86_MCE_THRESHOLD
879 depends on X86_MCE_AMD || X86_MCE_INTEL
882 config X86_MCE_INJECT
884 tristate "Machine check injector support"
886 Provide support for injecting machine checks for testing purposes.
887 If you don't know what a machine check is and you don't do kernel
888 QA it is safe to say n.
890 config X86_THERMAL_VECTOR
892 depends on X86_MCE_INTEL
895 bool "Enable VM86 support" if EXPERT
899 This option is required by programs like DOSEMU to run 16-bit legacy
900 code on X86 processors. It also may be needed by software like
901 XFree86 to initialize some video cards via BIOS. Disabling this
902 option saves about 6k.
905 tristate "Toshiba Laptop support"
908 This adds a driver to safely access the System Management Mode of
909 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
910 not work on models with a Phoenix BIOS. The System Management Mode
911 is used to set the BIOS and power saving options on Toshiba portables.
913 For information on utilities to make use of this driver see the
914 Toshiba Linux utilities web site at:
915 <http://www.buzzard.org.uk/toshiba/>.
917 Say Y if you intend to run this kernel on a Toshiba portable.
921 tristate "Dell laptop support"
924 This adds a driver to safely access the System Management Mode
925 of the CPU on the Dell Inspiron 8000. The System Management Mode
926 is used to read cpu temperature and cooling fan status and to
927 control the fans on the I8K portables.
929 This driver has been tested only on the Inspiron 8000 but it may
930 also work with other Dell laptops. You can force loading on other
931 models by passing the parameter `force=1' to the module. Use at
934 For information on utilities to make use of this driver see the
935 I8K Linux utilities web site at:
936 <http://people.debian.org/~dz/i8k/>
938 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
941 config X86_REBOOTFIXUPS
942 bool "Enable X86 board specific fixups for reboot"
945 This enables chipset and/or board specific fixups to be done
946 in order to get reboot to work correctly. This is only needed on
947 some combinations of hardware and BIOS. The symptom, for which
948 this config is intended, is when reboot ends with a stalled/hung
951 Currently, the only fixup is for the Geode machines using
952 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
954 Say Y if you want to enable the fixup. Currently, it's safe to
955 enable this option even if you don't need it.
959 tristate "/dev/cpu/microcode - microcode support"
962 If you say Y here, you will be able to update the microcode on
963 certain Intel and AMD processors. The Intel support is for the
964 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
965 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
966 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
967 You will obviously need the actual microcode binary data itself
968 which is not shipped with the Linux kernel.
970 This option selects the general module only, you need to select
971 at least one vendor specific module as well.
973 To compile this driver as a module, choose M here: the
974 module will be called microcode.
976 config MICROCODE_INTEL
977 bool "Intel microcode patch loading support"
982 This options enables microcode patch loading support for Intel
985 For latest news and information on obtaining all the required
986 Intel ingredients for this driver, check:
987 <http://www.urbanmyth.org/microcode/>.
990 bool "AMD microcode patch loading support"
994 If you select this option, microcode patch loading support for AMD
995 processors will be enabled.
997 config MICROCODE_OLD_INTERFACE
1002 tristate "/dev/cpu/*/msr - Model-specific register support"
1004 This device gives privileged processes access to the x86
1005 Model-Specific Registers (MSRs). It is a character device with
1006 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1007 MSR accesses are directed to a specific CPU on multi-processor
1011 tristate "/dev/cpu/*/cpuid - CPU information support"
1013 This device gives processes access to the x86 CPUID instruction to
1014 be executed on a specific processor. It is a character device
1015 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1019 prompt "High Memory Support"
1020 default HIGHMEM64G if X86_NUMAQ
1026 depends on !X86_NUMAQ
1028 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1029 However, the address space of 32-bit x86 processors is only 4
1030 Gigabytes large. That means that, if you have a large amount of
1031 physical memory, not all of it can be "permanently mapped" by the
1032 kernel. The physical memory that's not permanently mapped is called
1035 If you are compiling a kernel which will never run on a machine with
1036 more than 1 Gigabyte total physical RAM, answer "off" here (default
1037 choice and suitable for most users). This will result in a "3GB/1GB"
1038 split: 3GB are mapped so that each process sees a 3GB virtual memory
1039 space and the remaining part of the 4GB virtual memory space is used
1040 by the kernel to permanently map as much physical memory as
1043 If the machine has between 1 and 4 Gigabytes physical RAM, then
1046 If more than 4 Gigabytes is used then answer "64GB" here. This
1047 selection turns Intel PAE (Physical Address Extension) mode on.
1048 PAE implements 3-level paging on IA32 processors. PAE is fully
1049 supported by Linux, PAE mode is implemented on all recent Intel
1050 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1051 then the kernel will not boot on CPUs that don't support PAE!
1053 The actual amount of total physical memory will either be
1054 auto detected or can be forced by using a kernel command line option
1055 such as "mem=256M". (Try "man bootparam" or see the documentation of
1056 your boot loader (lilo or loadlin) about how to pass options to the
1057 kernel at boot time.)
1059 If unsure, say "off".
1063 depends on !X86_NUMAQ
1065 Select this if you have a 32-bit processor and between 1 and 4
1066 gigabytes of physical RAM.
1070 depends on !M386 && !M486
1073 Select this if you have a 32-bit processor and more than 4
1074 gigabytes of physical RAM.
1079 depends on EXPERIMENTAL
1080 prompt "Memory split" if EXPERT
1084 Select the desired split between kernel and user memory.
1086 If the address range available to the kernel is less than the
1087 physical memory installed, the remaining memory will be available
1088 as "high memory". Accessing high memory is a little more costly
1089 than low memory, as it needs to be mapped into the kernel first.
1090 Note that increasing the kernel address space limits the range
1091 available to user programs, making the address space there
1092 tighter. Selecting anything other than the default 3G/1G split
1093 will also likely make your kernel incompatible with binary-only
1096 If you are not absolutely sure what you are doing, leave this
1100 bool "3G/1G user/kernel split"
1101 config VMSPLIT_3G_OPT
1103 bool "3G/1G user/kernel split (for full 1G low memory)"
1105 bool "2G/2G user/kernel split"
1106 config VMSPLIT_2G_OPT
1108 bool "2G/2G user/kernel split (for full 2G low memory)"
1110 bool "1G/3G user/kernel split"
1115 default 0xB0000000 if VMSPLIT_3G_OPT
1116 default 0x80000000 if VMSPLIT_2G
1117 default 0x78000000 if VMSPLIT_2G_OPT
1118 default 0x40000000 if VMSPLIT_1G
1124 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1127 bool "PAE (Physical Address Extension) Support"
1128 depends on X86_32 && !HIGHMEM4G
1130 PAE is required for NX support, and furthermore enables
1131 larger swapspace support for non-overcommit purposes. It
1132 has the cost of more pagetable lookup overhead, and also
1133 consumes more pagetable space per process.
1135 config ARCH_PHYS_ADDR_T_64BIT
1136 def_bool X86_64 || X86_PAE
1138 config ARCH_DMA_ADDR_T_64BIT
1139 def_bool X86_64 || HIGHMEM64G
1141 config DIRECT_GBPAGES
1142 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1146 Allow the kernel linear mapping to use 1GB pages on CPUs that
1147 support it. This can improve the kernel's performance a tiny bit by
1148 reducing TLB pressure. If in doubt, say "Y".
1150 # Common NUMA Features
1152 bool "Numa Memory Allocation and Scheduler Support"
1154 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1155 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1157 Enable NUMA (Non Uniform Memory Access) support.
1159 The kernel will try to allocate memory used by a CPU on the
1160 local memory controller of the CPU and add some more
1161 NUMA awareness to the kernel.
1163 For 64-bit this is recommended if the system is Intel Core i7
1164 (or later), AMD Opteron, or EM64T NUMA.
1166 For 32-bit this is only needed on (rare) 32-bit-only platforms
1167 that support NUMA topologies, such as NUMAQ / Summit, or if you
1168 boot a 32-bit kernel on a 64-bit NUMA platform.
1170 Otherwise, you should say N.
1172 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1173 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1177 prompt "Old style AMD Opteron NUMA detection"
1178 depends on X86_64 && NUMA && PCI
1180 Enable AMD NUMA node topology detection. You should say Y here if
1181 you have a multi processor AMD system. This uses an old method to
1182 read the NUMA configuration directly from the builtin Northbridge
1183 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1184 which also takes priority if both are compiled in.
1186 config X86_64_ACPI_NUMA
1188 prompt "ACPI NUMA detection"
1189 depends on X86_64 && NUMA && ACPI && PCI
1192 Enable ACPI SRAT based node topology detection.
1194 # Some NUMA nodes have memory ranges that span
1195 # other nodes. Even though a pfn is valid and
1196 # between a node's start and end pfns, it may not
1197 # reside on that node. See memmap_init_zone()
1199 config NODES_SPAN_OTHER_NODES
1201 depends on X86_64_ACPI_NUMA
1204 bool "NUMA emulation"
1207 Enable NUMA emulation. A flat machine will be split
1208 into virtual nodes when booted with "numa=fake=N", where N is the
1209 number of nodes. This is only useful for debugging.
1212 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1214 default "10" if MAXSMP
1215 default "6" if X86_64
1216 default "4" if X86_NUMAQ
1218 depends on NEED_MULTIPLE_NODES
1220 Specify the maximum number of NUMA Nodes available on the target
1221 system. Increases memory reserved to accommodate various tables.
1223 config HAVE_ARCH_BOOTMEM
1225 depends on X86_32 && NUMA
1227 config HAVE_ARCH_ALLOC_REMAP
1229 depends on X86_32 && NUMA
1231 config ARCH_HAVE_MEMORY_PRESENT
1233 depends on X86_32 && DISCONTIGMEM
1235 config NEED_NODE_MEMMAP_SIZE
1237 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1239 config ARCH_FLATMEM_ENABLE
1241 depends on X86_32 && !NUMA
1243 config ARCH_DISCONTIGMEM_ENABLE
1245 depends on NUMA && X86_32
1247 config ARCH_DISCONTIGMEM_DEFAULT
1249 depends on NUMA && X86_32
1251 config ARCH_SPARSEMEM_ENABLE
1253 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1254 select SPARSEMEM_STATIC if X86_32
1255 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1257 config ARCH_SPARSEMEM_DEFAULT
1261 config ARCH_SELECT_MEMORY_MODEL
1263 depends on ARCH_SPARSEMEM_ENABLE
1265 config ARCH_MEMORY_PROBE
1267 depends on MEMORY_HOTPLUG
1269 config ARCH_PROC_KCORE_TEXT
1271 depends on X86_64 && PROC_KCORE
1273 config ILLEGAL_POINTER_VALUE
1276 default 0xdead000000000000 if X86_64
1281 bool "Allocate 3rd-level pagetables from highmem"
1284 The VM uses one page table entry for each page of physical memory.
1285 For systems with a lot of RAM, this can be wasteful of precious
1286 low memory. Setting this option will put user-space page table
1287 entries in high memory.
1289 config X86_CHECK_BIOS_CORRUPTION
1290 bool "Check for low memory corruption"
1292 Periodically check for memory corruption in low memory, which
1293 is suspected to be caused by BIOS. Even when enabled in the
1294 configuration, it is disabled at runtime. Enable it by
1295 setting "memory_corruption_check=1" on the kernel command
1296 line. By default it scans the low 64k of memory every 60
1297 seconds; see the memory_corruption_check_size and
1298 memory_corruption_check_period parameters in
1299 Documentation/kernel-parameters.txt to adjust this.
1301 When enabled with the default parameters, this option has
1302 almost no overhead, as it reserves a relatively small amount
1303 of memory and scans it infrequently. It both detects corruption
1304 and prevents it from affecting the running system.
1306 It is, however, intended as a diagnostic tool; if repeatable
1307 BIOS-originated corruption always affects the same memory,
1308 you can use memmap= to prevent the kernel from using that
1311 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1312 bool "Set the default setting of memory_corruption_check"
1313 depends on X86_CHECK_BIOS_CORRUPTION
1316 Set whether the default state of memory_corruption_check is
1319 config X86_RESERVE_LOW
1320 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1324 Specify the amount of low memory to reserve for the BIOS.
1326 The first page contains BIOS data structures that the kernel
1327 must not use, so that page must always be reserved.
1329 By default we reserve the first 64K of physical RAM, as a
1330 number of BIOSes are known to corrupt that memory range
1331 during events such as suspend/resume or monitor cable
1332 insertion, so it must not be used by the kernel.
1334 You can set this to 4 if you are absolutely sure that you
1335 trust the BIOS to get all its memory reservations and usages
1336 right. If you know your BIOS have problems beyond the
1337 default 64K area, you can set this to 640 to avoid using the
1338 entire low memory range.
1340 If you have doubts about the BIOS (e.g. suspend/resume does
1341 not work or there's kernel crashes after certain hardware
1342 hotplug events) then you might want to enable
1343 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1344 typical corruption patterns.
1346 Leave this to the default value of 64 if you are unsure.
1348 config MATH_EMULATION
1350 prompt "Math emulation" if X86_32
1352 Linux can emulate a math coprocessor (used for floating point
1353 operations) if you don't have one. 486DX and Pentium processors have
1354 a math coprocessor built in, 486SX and 386 do not, unless you added
1355 a 487DX or 387, respectively. (The messages during boot time can
1356 give you some hints here ["man dmesg"].) Everyone needs either a
1357 coprocessor or this emulation.
1359 If you don't have a math coprocessor, you need to say Y here; if you
1360 say Y here even though you have a coprocessor, the coprocessor will
1361 be used nevertheless. (This behavior can be changed with the kernel
1362 command line option "no387", which comes handy if your coprocessor
1363 is broken. Try "man bootparam" or see the documentation of your boot
1364 loader (lilo or loadlin) about how to pass options to the kernel at
1365 boot time.) This means that it is a good idea to say Y here if you
1366 intend to use this kernel on different machines.
1368 More information about the internals of the Linux math coprocessor
1369 emulation can be found in <file:arch/x86/math-emu/README>.
1371 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1372 kernel, it won't hurt.
1376 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1378 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1379 the Memory Type Range Registers (MTRRs) may be used to control
1380 processor access to memory ranges. This is most useful if you have
1381 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1382 allows bus write transfers to be combined into a larger transfer
1383 before bursting over the PCI/AGP bus. This can increase performance
1384 of image write operations 2.5 times or more. Saying Y here creates a
1385 /proc/mtrr file which may be used to manipulate your processor's
1386 MTRRs. Typically the X server should use this.
1388 This code has a reasonably generic interface so that similar
1389 control registers on other processors can be easily supported
1392 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1393 Registers (ARRs) which provide a similar functionality to MTRRs. For
1394 these, the ARRs are used to emulate the MTRRs.
1395 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1396 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1397 write-combining. All of these processors are supported by this code
1398 and it makes sense to say Y here if you have one of them.
1400 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1401 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1402 can lead to all sorts of problems, so it's good to say Y here.
1404 You can safely say Y even if your machine doesn't have MTRRs, you'll
1405 just add about 9 KB to your kernel.
1407 See <file:Documentation/x86/mtrr.txt> for more information.
1409 config MTRR_SANITIZER
1411 prompt "MTRR cleanup support"
1414 Convert MTRR layout from continuous to discrete, so X drivers can
1415 add writeback entries.
1417 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1418 The largest mtrr entry size for a continuous block can be set with
1423 config MTRR_SANITIZER_ENABLE_DEFAULT
1424 int "MTRR cleanup enable value (0-1)"
1427 depends on MTRR_SANITIZER
1429 Enable mtrr cleanup default value
1431 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1432 int "MTRR cleanup spare reg num (0-7)"
1435 depends on MTRR_SANITIZER
1437 mtrr cleanup spare entries default, it can be changed via
1438 mtrr_spare_reg_nr=N on the kernel command line.
1442 prompt "x86 PAT support" if EXPERT
1445 Use PAT attributes to setup page level cache control.
1447 PATs are the modern equivalents of MTRRs and are much more
1448 flexible than MTRRs.
1450 Say N here if you see bootup problems (boot crash, boot hang,
1451 spontaneous reboots) or a non-working video driver.
1455 config ARCH_USES_PG_UNCACHED
1461 prompt "x86 architectural random number generator" if EXPERT
1463 Enable the x86 architectural RDRAND instruction
1464 (Intel Bull Mountain technology) to generate random numbers.
1465 If supported, this is a high bandwidth, cryptographically
1466 secure hardware random number generator.
1469 bool "EFI runtime service support"
1472 This enables the kernel to use EFI runtime services that are
1473 available (such as the EFI variable services).
1475 This option is only useful on systems that have EFI firmware.
1476 In addition, you should use the latest ELILO loader available
1477 at <http://elilo.sourceforge.net> in order to take advantage
1478 of EFI runtime services. However, even with this option, the
1479 resultant kernel should continue to boot on existing non-EFI
1483 bool "EFI stub support"
1486 This kernel feature allows a bzImage to be loaded directly
1487 by EFI firmware without the use of a bootloader.
1491 prompt "Enable seccomp to safely compute untrusted bytecode"
1493 This kernel feature is useful for number crunching applications
1494 that may need to compute untrusted bytecode during their
1495 execution. By using pipes or other transports made available to
1496 the process as file descriptors supporting the read/write
1497 syscalls, it's possible to isolate those applications in
1498 their own address space using seccomp. Once seccomp is
1499 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1500 and the task is only allowed to execute a few safe syscalls
1501 defined by each seccomp mode.
1503 If unsure, say Y. Only embedded should say N here.
1505 config CC_STACKPROTECTOR
1506 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1508 This option turns on the -fstack-protector GCC feature. This
1509 feature puts, at the beginning of functions, a canary value on
1510 the stack just before the return address, and validates
1511 the value just before actually returning. Stack based buffer
1512 overflows (that need to overwrite this return address) now also
1513 overwrite the canary, which gets detected and the attack is then
1514 neutralized via a kernel panic.
1516 This feature requires gcc version 4.2 or above, or a distribution
1517 gcc with the feature backported. Older versions are automatically
1518 detected and for those versions, this configuration option is
1519 ignored. (and a warning is printed during bootup)
1521 source kernel/Kconfig.hz
1524 bool "kexec system call"
1526 kexec is a system call that implements the ability to shutdown your
1527 current kernel, and to start another kernel. It is like a reboot
1528 but it is independent of the system firmware. And like a reboot
1529 you can start any kernel with it, not just Linux.
1531 The name comes from the similarity to the exec system call.
1533 It is an ongoing process to be certain the hardware in a machine
1534 is properly shutdown, so do not be surprised if this code does not
1535 initially work for you. It may help to enable device hotplugging
1536 support. As of this writing the exact hardware interface is
1537 strongly in flux, so no good recommendation can be made.
1540 bool "kernel crash dumps"
1541 depends on X86_64 || (X86_32 && HIGHMEM)
1543 Generate crash dump after being started by kexec.
1544 This should be normally only set in special crash dump kernels
1545 which are loaded in the main kernel with kexec-tools into
1546 a specially reserved region and then later executed after
1547 a crash by kdump/kexec. The crash dump kernel must be compiled
1548 to a memory address not used by the main kernel or BIOS using
1549 PHYSICAL_START, or it must be built as a relocatable image
1550 (CONFIG_RELOCATABLE=y).
1551 For more details see Documentation/kdump/kdump.txt
1554 bool "kexec jump (EXPERIMENTAL)"
1555 depends on EXPERIMENTAL
1556 depends on KEXEC && HIBERNATION
1558 Jump between original kernel and kexeced kernel and invoke
1559 code in physical address mode via KEXEC
1561 config PHYSICAL_START
1562 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1565 This gives the physical address where the kernel is loaded.
1567 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1568 bzImage will decompress itself to above physical address and
1569 run from there. Otherwise, bzImage will run from the address where
1570 it has been loaded by the boot loader and will ignore above physical
1573 In normal kdump cases one does not have to set/change this option
1574 as now bzImage can be compiled as a completely relocatable image
1575 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1576 address. This option is mainly useful for the folks who don't want
1577 to use a bzImage for capturing the crash dump and want to use a
1578 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1579 to be specifically compiled to run from a specific memory area
1580 (normally a reserved region) and this option comes handy.
1582 So if you are using bzImage for capturing the crash dump,
1583 leave the value here unchanged to 0x1000000 and set
1584 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1585 for capturing the crash dump change this value to start of
1586 the reserved region. In other words, it can be set based on
1587 the "X" value as specified in the "crashkernel=YM@XM"
1588 command line boot parameter passed to the panic-ed
1589 kernel. Please take a look at Documentation/kdump/kdump.txt
1590 for more details about crash dumps.
1592 Usage of bzImage for capturing the crash dump is recommended as
1593 one does not have to build two kernels. Same kernel can be used
1594 as production kernel and capture kernel. Above option should have
1595 gone away after relocatable bzImage support is introduced. But it
1596 is present because there are users out there who continue to use
1597 vmlinux for dump capture. This option should go away down the
1600 Don't change this unless you know what you are doing.
1603 bool "Build a relocatable kernel"
1606 This builds a kernel image that retains relocation information
1607 so it can be loaded someplace besides the default 1MB.
1608 The relocations tend to make the kernel binary about 10% larger,
1609 but are discarded at runtime.
1611 One use is for the kexec on panic case where the recovery kernel
1612 must live at a different physical address than the primary
1615 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1616 it has been loaded at and the compile time physical address
1617 (CONFIG_PHYSICAL_START) is ignored.
1619 # Relocation on x86-32 needs some additional build support
1620 config X86_NEED_RELOCS
1622 depends on X86_32 && RELOCATABLE
1624 config PHYSICAL_ALIGN
1625 hex "Alignment value to which kernel should be aligned" if X86_32
1627 range 0x2000 0x1000000
1629 This value puts the alignment restrictions on physical address
1630 where kernel is loaded and run from. Kernel is compiled for an
1631 address which meets above alignment restriction.
1633 If bootloader loads the kernel at a non-aligned address and
1634 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1635 address aligned to above value and run from there.
1637 If bootloader loads the kernel at a non-aligned address and
1638 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1639 load address and decompress itself to the address it has been
1640 compiled for and run from there. The address for which kernel is
1641 compiled already meets above alignment restrictions. Hence the
1642 end result is that kernel runs from a physical address meeting
1643 above alignment restrictions.
1645 Don't change this unless you know what you are doing.
1648 bool "Support for hot-pluggable CPUs"
1649 depends on SMP && HOTPLUG
1651 Say Y here to allow turning CPUs off and on. CPUs can be
1652 controlled through /sys/devices/system/cpu.
1653 ( Note: power management support will enable this option
1654 automatically on SMP systems. )
1655 Say N if you want to disable CPU hotplug.
1659 prompt "Compat VDSO support"
1660 depends on X86_32 || IA32_EMULATION
1662 Map the 32-bit VDSO to the predictable old-style address too.
1664 Say N here if you are running a sufficiently recent glibc
1665 version (2.3.3 or later), to remove the high-mapped
1666 VDSO mapping and to exclusively use the randomized VDSO.
1671 bool "Built-in kernel command line"
1673 Allow for specifying boot arguments to the kernel at
1674 build time. On some systems (e.g. embedded ones), it is
1675 necessary or convenient to provide some or all of the
1676 kernel boot arguments with the kernel itself (that is,
1677 to not rely on the boot loader to provide them.)
1679 To compile command line arguments into the kernel,
1680 set this option to 'Y', then fill in the
1681 the boot arguments in CONFIG_CMDLINE.
1683 Systems with fully functional boot loaders (i.e. non-embedded)
1684 should leave this option set to 'N'.
1687 string "Built-in kernel command string"
1688 depends on CMDLINE_BOOL
1691 Enter arguments here that should be compiled into the kernel
1692 image and used at boot time. If the boot loader provides a
1693 command line at boot time, it is appended to this string to
1694 form the full kernel command line, when the system boots.
1696 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1697 change this behavior.
1699 In most cases, the command line (whether built-in or provided
1700 by the boot loader) should specify the device for the root
1703 config CMDLINE_OVERRIDE
1704 bool "Built-in command line overrides boot loader arguments"
1705 depends on CMDLINE_BOOL
1707 Set this option to 'Y' to have the kernel ignore the boot loader
1708 command line, and use ONLY the built-in command line.
1710 This is used to work around broken boot loaders. This should
1711 be set to 'N' under normal conditions.
1715 config ARCH_ENABLE_MEMORY_HOTPLUG
1717 depends on X86_64 || (X86_32 && HIGHMEM)
1719 config ARCH_ENABLE_MEMORY_HOTREMOVE
1721 depends on MEMORY_HOTPLUG
1723 config USE_PERCPU_NUMA_NODE_ID
1727 menu "Power management and ACPI options"
1729 config ARCH_HIBERNATION_HEADER
1731 depends on X86_64 && HIBERNATION
1733 source "kernel/power/Kconfig"
1735 source "drivers/acpi/Kconfig"
1737 source "drivers/sfi/Kconfig"
1744 tristate "APM (Advanced Power Management) BIOS support"
1745 depends on X86_32 && PM_SLEEP
1747 APM is a BIOS specification for saving power using several different
1748 techniques. This is mostly useful for battery powered laptops with
1749 APM compliant BIOSes. If you say Y here, the system time will be
1750 reset after a RESUME operation, the /proc/apm device will provide
1751 battery status information, and user-space programs will receive
1752 notification of APM "events" (e.g. battery status change).
1754 If you select "Y" here, you can disable actual use of the APM
1755 BIOS by passing the "apm=off" option to the kernel at boot time.
1757 Note that the APM support is almost completely disabled for
1758 machines with more than one CPU.
1760 In order to use APM, you will need supporting software. For location
1761 and more information, read <file:Documentation/power/apm-acpi.txt>
1762 and the Battery Powered Linux mini-HOWTO, available from
1763 <http://www.tldp.org/docs.html#howto>.
1765 This driver does not spin down disk drives (see the hdparm(8)
1766 manpage ("man 8 hdparm") for that), and it doesn't turn off
1767 VESA-compliant "green" monitors.
1769 This driver does not support the TI 4000M TravelMate and the ACER
1770 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1771 desktop machines also don't have compliant BIOSes, and this driver
1772 may cause those machines to panic during the boot phase.
1774 Generally, if you don't have a battery in your machine, there isn't
1775 much point in using this driver and you should say N. If you get
1776 random kernel OOPSes or reboots that don't seem to be related to
1777 anything, try disabling/enabling this option (or disabling/enabling
1780 Some other things you should try when experiencing seemingly random,
1783 1) make sure that you have enough swap space and that it is
1785 2) pass the "no-hlt" option to the kernel
1786 3) switch on floating point emulation in the kernel and pass
1787 the "no387" option to the kernel
1788 4) pass the "floppy=nodma" option to the kernel
1789 5) pass the "mem=4M" option to the kernel (thereby disabling
1790 all but the first 4 MB of RAM)
1791 6) make sure that the CPU is not over clocked.
1792 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1793 8) disable the cache from your BIOS settings
1794 9) install a fan for the video card or exchange video RAM
1795 10) install a better fan for the CPU
1796 11) exchange RAM chips
1797 12) exchange the motherboard.
1799 To compile this driver as a module, choose M here: the
1800 module will be called apm.
1804 config APM_IGNORE_USER_SUSPEND
1805 bool "Ignore USER SUSPEND"
1807 This option will ignore USER SUSPEND requests. On machines with a
1808 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1809 series notebooks, it is necessary to say Y because of a BIOS bug.
1811 config APM_DO_ENABLE
1812 bool "Enable PM at boot time"
1814 Enable APM features at boot time. From page 36 of the APM BIOS
1815 specification: "When disabled, the APM BIOS does not automatically
1816 power manage devices, enter the Standby State, enter the Suspend
1817 State, or take power saving steps in response to CPU Idle calls."
1818 This driver will make CPU Idle calls when Linux is idle (unless this
1819 feature is turned off -- see "Do CPU IDLE calls", below). This
1820 should always save battery power, but more complicated APM features
1821 will be dependent on your BIOS implementation. You may need to turn
1822 this option off if your computer hangs at boot time when using APM
1823 support, or if it beeps continuously instead of suspending. Turn
1824 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1825 T400CDT. This is off by default since most machines do fine without
1829 bool "Make CPU Idle calls when idle"
1831 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1832 On some machines, this can activate improved power savings, such as
1833 a slowed CPU clock rate, when the machine is idle. These idle calls
1834 are made after the idle loop has run for some length of time (e.g.,
1835 333 mS). On some machines, this will cause a hang at boot time or
1836 whenever the CPU becomes idle. (On machines with more than one CPU,
1837 this option does nothing.)
1839 config APM_DISPLAY_BLANK
1840 bool "Enable console blanking using APM"
1842 Enable console blanking using the APM. Some laptops can use this to
1843 turn off the LCD backlight when the screen blanker of the Linux
1844 virtual console blanks the screen. Note that this is only used by
1845 the virtual console screen blanker, and won't turn off the backlight
1846 when using the X Window system. This also doesn't have anything to
1847 do with your VESA-compliant power-saving monitor. Further, this
1848 option doesn't work for all laptops -- it might not turn off your
1849 backlight at all, or it might print a lot of errors to the console,
1850 especially if you are using gpm.
1852 config APM_ALLOW_INTS
1853 bool "Allow interrupts during APM BIOS calls"
1855 Normally we disable external interrupts while we are making calls to
1856 the APM BIOS as a measure to lessen the effects of a badly behaving
1857 BIOS implementation. The BIOS should reenable interrupts if it
1858 needs to. Unfortunately, some BIOSes do not -- especially those in
1859 many of the newer IBM Thinkpads. If you experience hangs when you
1860 suspend, try setting this to Y. Otherwise, say N.
1864 source "drivers/cpufreq/Kconfig"
1866 source "drivers/cpuidle/Kconfig"
1868 source "drivers/idle/Kconfig"
1873 menu "Bus options (PCI etc.)"
1878 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1880 Find out whether you have a PCI motherboard. PCI is the name of a
1881 bus system, i.e. the way the CPU talks to the other stuff inside
1882 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1883 VESA. If you have PCI, say Y, otherwise N.
1886 prompt "PCI access mode"
1887 depends on X86_32 && PCI
1890 On PCI systems, the BIOS can be used to detect the PCI devices and
1891 determine their configuration. However, some old PCI motherboards
1892 have BIOS bugs and may crash if this is done. Also, some embedded
1893 PCI-based systems don't have any BIOS at all. Linux can also try to
1894 detect the PCI hardware directly without using the BIOS.
1896 With this option, you can specify how Linux should detect the
1897 PCI devices. If you choose "BIOS", the BIOS will be used,
1898 if you choose "Direct", the BIOS won't be used, and if you
1899 choose "MMConfig", then PCI Express MMCONFIG will be used.
1900 If you choose "Any", the kernel will try MMCONFIG, then the
1901 direct access method and falls back to the BIOS if that doesn't
1902 work. If unsure, go with the default, which is "Any".
1907 config PCI_GOMMCONFIG
1924 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1926 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1929 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1933 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1937 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1941 depends on PCI && XEN
1949 bool "Support mmconfig PCI config space access"
1950 depends on X86_64 && PCI && ACPI
1952 config PCI_CNB20LE_QUIRK
1953 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1955 depends on PCI && EXPERIMENTAL
1957 Read the PCI windows out of the CNB20LE host bridge. This allows
1958 PCI hotplug to work on systems with the CNB20LE chipset which do
1961 There's no public spec for this chipset, and this functionality
1962 is known to be incomplete.
1964 You should say N unless you know you need this.
1966 source "drivers/pci/pcie/Kconfig"
1968 source "drivers/pci/Kconfig"
1970 # x86_64 have no ISA slots, but can have ISA-style DMA.
1972 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1975 Enables ISA-style DMA support for devices requiring such controllers.
1983 Find out whether you have ISA slots on your motherboard. ISA is the
1984 name of a bus system, i.e. the way the CPU talks to the other stuff
1985 inside your box. Other bus systems are PCI, EISA, MicroChannel
1986 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1987 newer boards don't support it. If you have ISA, say Y, otherwise N.
1993 The Extended Industry Standard Architecture (EISA) bus was
1994 developed as an open alternative to the IBM MicroChannel bus.
1996 The EISA bus provided some of the features of the IBM MicroChannel
1997 bus while maintaining backward compatibility with cards made for
1998 the older ISA bus. The EISA bus saw limited use between 1988 and
1999 1995 when it was made obsolete by the PCI bus.
2001 Say Y here if you are building a kernel for an EISA-based machine.
2005 source "drivers/eisa/Kconfig"
2010 MicroChannel Architecture is found in some IBM PS/2 machines and
2011 laptops. It is a bus system similar to PCI or ISA. See
2012 <file:Documentation/mca.txt> (and especially the web page given
2013 there) before attempting to build an MCA bus kernel.
2015 source "drivers/mca/Kconfig"
2018 tristate "NatSemi SCx200 support"
2020 This provides basic support for National Semiconductor's
2021 (now AMD's) Geode processors. The driver probes for the
2022 PCI-IDs of several on-chip devices, so its a good dependency
2023 for other scx200_* drivers.
2025 If compiled as a module, the driver is named scx200.
2027 config SCx200HR_TIMER
2028 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2032 This driver provides a clocksource built upon the on-chip
2033 27MHz high-resolution timer. Its also a workaround for
2034 NSC Geode SC-1100's buggy TSC, which loses time when the
2035 processor goes idle (as is done by the scheduler). The
2036 other workaround is idle=poll boot option.
2039 bool "One Laptop Per Child support"
2046 Add support for detecting the unique features of the OLPC
2050 bool "OLPC XO-1 Power Management"
2051 depends on OLPC && MFD_CS5535 && PM_SLEEP
2054 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2057 bool "OLPC XO-1 Real Time Clock"
2058 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2060 Add support for the XO-1 real time clock, which can be used as a
2061 programmable wakeup source.
2064 bool "OLPC XO-1 SCI extras"
2065 depends on OLPC && OLPC_XO1_PM
2070 Add support for SCI-based features of the OLPC XO-1 laptop:
2071 - EC-driven system wakeups
2075 - AC adapter status updates
2076 - Battery status updates
2078 config OLPC_XO15_SCI
2079 bool "OLPC XO-1.5 SCI extras"
2080 depends on OLPC && ACPI
2083 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2084 - EC-driven system wakeups
2085 - AC adapter status updates
2086 - Battery status updates
2089 bool "PCEngines ALIX System Support (LED setup)"
2092 This option enables system support for the PCEngines ALIX.
2093 At present this just sets up LEDs for GPIO control on
2094 ALIX2/3/6 boards. However, other system specific setup should
2097 Note: You must still enable the drivers for GPIO and LED support
2098 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2100 Note: You have to set alix.force=1 for boards with Award BIOS.
2103 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2106 This option enables system support for the Soekris Engineering net5501.
2109 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2113 This option enables system support for the Traverse Technologies GEOS.
2119 depends on CPU_SUP_AMD && PCI
2121 source "drivers/pcmcia/Kconfig"
2123 source "drivers/pci/hotplug/Kconfig"
2126 bool "RapidIO support"
2130 If you say Y here, the kernel will include drivers and
2131 infrastructure code to support RapidIO interconnect devices.
2133 source "drivers/rapidio/Kconfig"
2138 menu "Executable file formats / Emulations"
2140 source "fs/Kconfig.binfmt"
2142 config IA32_EMULATION
2143 bool "IA32 Emulation"
2145 select COMPAT_BINFMT_ELF
2147 Include code to run legacy 32-bit programs under a
2148 64-bit kernel. You should likely turn this on, unless you're
2149 100% sure that you don't have any 32-bit programs left.
2152 tristate "IA32 a.out support"
2153 depends on IA32_EMULATION
2155 Support old a.out binaries in the 32bit emulation.
2158 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2159 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2161 Include code to run binaries for the x32 native 32-bit ABI
2162 for 64-bit processors. An x32 process gets access to the
2163 full 64-bit register file and wide data path while leaving
2164 pointers at 32 bits for smaller memory footprint.
2166 You will need a recent binutils (2.22 or later) with
2167 elf32_x86_64 support enabled to compile a kernel with this
2172 depends on IA32_EMULATION || X86_X32
2173 select ARCH_WANT_OLD_COMPAT_IPC
2175 config COMPAT_FOR_U64_ALIGNMENT
2179 config SYSVIPC_COMPAT
2181 depends on COMPAT && SYSVIPC
2185 depends on COMPAT && KEYS
2191 config HAVE_ATOMIC_IOMAP
2195 config HAVE_TEXT_POKE_SMP
2197 select STOP_MACHINE if SMP
2199 source "net/Kconfig"
2201 source "drivers/Kconfig"
2203 source "drivers/firmware/Kconfig"
2207 source "arch/x86/Kconfig.debug"
2209 source "security/Kconfig"
2211 source "crypto/Kconfig"
2213 source "arch/x86/kvm/Kconfig"
2215 source "lib/Kconfig"