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
67 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_PENDING_IRQ if SMP
70 select GENERIC_IRQ_SHOW
71 select IRQ_FORCED_THREADING
72 select USE_GENERIC_SMP_HELPERS if SMP
73 select HAVE_BPF_JIT if (X86_64 && NET)
76 config INSTRUCTION_DECODER
77 def_bool (KPROBES || PERF_EVENTS)
81 default "elf32-i386" if X86_32
82 default "elf64-x86-64" if X86_64
86 default "arch/x86/configs/i386_defconfig" if X86_32
87 default "arch/x86/configs/x86_64_defconfig" if X86_64
89 config GENERIC_CMOS_UPDATE
92 config CLOCKSOURCE_WATCHDOG
95 config GENERIC_CLOCKEVENTS
98 config ARCH_CLOCKSOURCE_DATA
102 config GENERIC_CLOCKEVENTS_BROADCAST
104 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
106 config LOCKDEP_SUPPORT
109 config STACKTRACE_SUPPORT
112 config HAVE_LATENCYTOP_SUPPORT
119 bool "DMA memory allocation support" if EXPERT
122 DMA memory allocation support allows devices with less than 32-bit
123 addressing to allocate within the first 16MB of address space.
124 Disable if no such devices will be used.
131 config NEED_DMA_MAP_STATE
132 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
134 config NEED_SG_DMA_LENGTH
137 config GENERIC_ISA_DMA
146 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
148 config GENERIC_BUG_RELATIVE_POINTERS
151 config GENERIC_HWEIGHT
157 config ARCH_MAY_HAVE_PC_FDC
160 config RWSEM_GENERIC_SPINLOCK
163 config RWSEM_XCHGADD_ALGORITHM
166 config ARCH_HAS_CPU_IDLE_WAIT
169 config GENERIC_CALIBRATE_DELAY
172 config GENERIC_TIME_VSYSCALL
176 config ARCH_HAS_CPU_RELAX
179 config ARCH_HAS_DEFAULT_IDLE
182 config ARCH_HAS_CACHE_LINE_SIZE
185 config HAVE_SETUP_PER_CPU_AREA
188 config NEED_PER_CPU_EMBED_FIRST_CHUNK
191 config NEED_PER_CPU_PAGE_FIRST_CHUNK
194 config HAVE_CPUMASK_OF_CPU_MAP
197 config ARCH_HIBERNATION_POSSIBLE
200 config ARCH_SUSPEND_POSSIBLE
207 config ARCH_POPULATES_NODE_MAP
214 config ARCH_SUPPORTS_OPTIMIZED_INLINING
217 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
220 config HAVE_INTEL_TXT
222 depends on EXPERIMENTAL && DMAR && ACPI
226 depends on X86_32 && SMP
230 depends on X86_64 && SMP
236 config X86_32_LAZY_GS
238 depends on X86_32 && !CC_STACKPROTECTOR
240 config ARCH_HWEIGHT_CFLAGS
242 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
243 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
248 config ARCH_CPU_PROBE_RELEASE
250 depends on HOTPLUG_CPU
252 source "init/Kconfig"
253 source "kernel/Kconfig.freezer"
255 menu "Processor type and features"
257 source "kernel/time/Kconfig"
260 bool "Symmetric multi-processing support"
262 This enables support for systems with more than one CPU. If you have
263 a system with only one CPU, like most personal computers, say N. If
264 you have a system with more than one CPU, say Y.
266 If you say N here, the kernel will run on single and multiprocessor
267 machines, but will use only one CPU of a multiprocessor machine. If
268 you say Y here, the kernel will run on many, but not all,
269 singleprocessor machines. On a singleprocessor machine, the kernel
270 will run faster if you say N here.
272 Note that if you say Y here and choose architecture "586" or
273 "Pentium" under "Processor family", the kernel will not work on 486
274 architectures. Similarly, multiprocessor kernels for the "PPro"
275 architecture may not work on all Pentium based boards.
277 People using multiprocessor machines who say Y here should also say
278 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
279 Management" code will be disabled if you say Y here.
281 See also <file:Documentation/i386/IO-APIC.txt>,
282 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
283 <http://www.tldp.org/docs.html#howto>.
285 If you don't know what to do here, say N.
288 bool "Support x2apic"
289 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
291 This enables x2apic support on CPUs that have this feature.
293 This allows 32-bit apic IDs (so it can support very large systems),
294 and accesses the local apic via MSRs not via mmio.
296 If you don't know what to do here, say N.
299 bool "Enable MPS table" if ACPI
301 depends on X86_LOCAL_APIC
303 For old smp systems that do not have proper acpi support. Newer systems
304 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
307 bool "Support for big SMP systems with more than 8 CPUs"
308 depends on X86_32 && SMP
310 This option is needed for the systems that have more than 8 CPUs
313 config X86_EXTENDED_PLATFORM
314 bool "Support for extended (non-PC) x86 platforms"
317 If you disable this option then the kernel will only support
318 standard PC platforms. (which covers the vast majority of
321 If you enable this option then you'll be able to select support
322 for the following (non-PC) 32 bit x86 platforms:
326 SGI 320/540 (Visual Workstation)
327 Summit/EXA (IBM x440)
328 Unisys ES7000 IA32 series
329 Moorestown MID devices
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
336 config X86_EXTENDED_PLATFORM
337 bool "Support for extended (non-PC) x86 platforms"
340 If you disable this option then the kernel will only support
341 standard PC platforms. (which covers the vast majority of
344 If you enable this option then you'll be able to select support
345 for the following (non-PC) 64 bit x86 platforms:
349 If you have one of these systems, or if you want to build a
350 generic distribution kernel, say Y here - otherwise say N.
352 # This is an alphabetically sorted list of 64 bit extended platforms
353 # Please maintain the alphabetic order if and when there are additions
357 select PARAVIRT_GUEST
359 depends on X86_64 && PCI
360 depends on X86_EXTENDED_PLATFORM
362 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
363 supposed to run on these EM64T-based machines. Only choose this option
364 if you have one of these machines.
367 bool "SGI Ultraviolet"
369 depends on X86_EXTENDED_PLATFORM
371 depends on X86_X2APIC
373 This option is needed in order to support SGI Ultraviolet systems.
374 If you don't have one of these, you should say N here.
376 # Following is an alphabetically sorted list of 32 bit extended platforms
377 # Please maintain the alphabetic order if and when there are additions
380 bool "CE4100 TV platform"
382 depends on PCI_GODIRECT
384 depends on X86_EXTENDED_PLATFORM
385 select X86_REBOOTFIXUPS
387 select OF_EARLY_FLATTREE
389 Select for the Intel CE media processor (CE4100) SOC.
390 This option compiles in support for the CE4100 SOC for settop
391 boxes and media devices.
394 bool "Moorestown MID platform"
398 depends on X86_EXTENDED_PLATFORM
399 depends on X86_IO_APIC
404 select X86_PLATFORM_DEVICES
406 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
407 Internet Device(MID) platform. Moorestown consists of two chips:
408 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
409 Unlike standard x86 PCs, Moorestown does not have many legacy devices
410 nor standard legacy replacement devices/features. e.g. Moorestown does
411 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
414 bool "RDC R-321x SoC"
416 depends on X86_EXTENDED_PLATFORM
418 select X86_REBOOTFIXUPS
420 This option is needed for RDC R-321x system-on-chip, also known
422 If you don't have one of these chips, you should say N here.
424 config X86_32_NON_STANDARD
425 bool "Support non-standard 32-bit SMP architectures"
426 depends on X86_32 && SMP
427 depends on X86_EXTENDED_PLATFORM
429 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
430 subarchitectures. It is intended for a generic binary kernel.
431 if you select them all, kernel will probe it one by one. and will
434 # Alphabetically sorted list of Non standard 32 bit platforms
437 bool "NUMAQ (IBM/Sequent)"
438 depends on X86_32_NON_STANDARD
443 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
444 NUMA multiquad box. This changes the way that processors are
445 bootstrapped, and uses Clustered Logical APIC addressing mode instead
446 of Flat Logical. You will need a new lynxer.elf file to flash your
447 firmware with - send email to <Martin.Bligh@us.ibm.com>.
449 config X86_SUPPORTS_MEMORY_FAILURE
451 # MCE code calls memory_failure():
453 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
454 depends on !X86_NUMAQ
455 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
456 depends on X86_64 || !SPARSEMEM
457 select ARCH_SUPPORTS_MEMORY_FAILURE
460 bool "SGI 320/540 (Visual Workstation)"
461 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
462 depends on X86_32_NON_STANDARD
464 The SGI Visual Workstation series is an IA32-based workstation
465 based on SGI systems chips with some legacy PC hardware attached.
467 Say Y here to create a kernel to run on the SGI 320 or 540.
469 A kernel compiled for the Visual Workstation will run on general
470 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
473 bool "Summit/EXA (IBM x440)"
474 depends on X86_32_NON_STANDARD
476 This option is needed for IBM systems that use the Summit/EXA chipset.
477 In particular, it is needed for the x440.
480 bool "Unisys ES7000 IA32 series"
481 depends on X86_32_NON_STANDARD && X86_BIGSMP
483 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
484 supposed to run on an IA32-based Unisys ES7000 system.
487 tristate "Eurobraille/Iris poweroff module"
490 The Iris machines from EuroBraille do not have APM or ACPI support
491 to shut themselves down properly. A special I/O sequence is
492 needed to do so, which is what this module does at
495 This is only for Iris machines from EuroBraille.
499 config SCHED_OMIT_FRAME_POINTER
501 prompt "Single-depth WCHAN output"
504 Calculate simpler /proc/<PID>/wchan values. If this option
505 is disabled then wchan values will recurse back to the
506 caller function. This provides more accurate wchan values,
507 at the expense of slightly more scheduling overhead.
509 If in doubt, say "Y".
511 menuconfig PARAVIRT_GUEST
512 bool "Paravirtualized guest support"
514 Say Y here to get to see options related to running Linux under
515 various hypervisors. This option alone does not add any kernel code.
517 If you say N, all options in this submenu will be skipped and disabled.
521 source "arch/x86/xen/Kconfig"
524 bool "KVM paravirtualized clock"
526 select PARAVIRT_CLOCK
528 Turning on this option will allow you to run a paravirtualized clock
529 when running over the KVM hypervisor. Instead of relying on a PIT
530 (or probably other) emulation by the underlying device model, the host
531 provides the guest with timing infrastructure such as time of day, and
535 bool "KVM Guest support"
538 This option enables various optimizations for running under the KVM
541 source "arch/x86/lguest/Kconfig"
544 bool "Enable paravirtualization code"
546 This changes the kernel so it can modify itself when it is run
547 under a hypervisor, potentially improving performance significantly
548 over full virtualization. However, when run without a hypervisor
549 the kernel is theoretically slower and slightly larger.
551 config PARAVIRT_SPINLOCKS
552 bool "Paravirtualization layer for spinlocks"
553 depends on PARAVIRT && SMP && EXPERIMENTAL
555 Paravirtualized spinlocks allow a pvops backend to replace the
556 spinlock implementation with something virtualization-friendly
557 (for example, block the virtual CPU rather than spinning).
559 Unfortunately the downside is an up to 5% performance hit on
560 native kernels, with various workloads.
562 If you are unsure how to answer this question, answer N.
564 config PARAVIRT_CLOCK
569 config PARAVIRT_DEBUG
570 bool "paravirt-ops debugging"
571 depends on PARAVIRT && DEBUG_KERNEL
573 Enable to debug paravirt_ops internals. Specifically, BUG if
574 a paravirt_op is missing when it is called.
582 This option adds a kernel parameter 'memtest', which allows memtest
584 memtest=0, mean disabled; -- default
585 memtest=1, mean do 1 test pattern;
587 memtest=4, mean do 4 test patterns.
588 If you are unsure how to answer this question, answer N.
590 config X86_SUMMIT_NUMA
592 depends on X86_32 && NUMA && X86_32_NON_STANDARD
594 config X86_CYCLONE_TIMER
596 depends on X86_32_NON_STANDARD
598 source "arch/x86/Kconfig.cpu"
602 prompt "HPET Timer Support" if X86_32
604 Use the IA-PC HPET (High Precision Event Timer) to manage
605 time in preference to the PIT and RTC, if a HPET is
607 HPET is the next generation timer replacing legacy 8254s.
608 The HPET provides a stable time base on SMP
609 systems, unlike the TSC, but it is more expensive to access,
610 as it is off-chip. You can find the HPET spec at
611 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
613 You can safely choose Y here. However, HPET will only be
614 activated if the platform and the BIOS support this feature.
615 Otherwise the 8254 will be used for timing services.
617 Choose N to continue using the legacy 8254 timer.
619 config HPET_EMULATE_RTC
621 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
625 prompt "Langwell APB Timer Support" if X86_MRST
628 APB timer is the replacement for 8254, HPET on X86 MID platforms.
629 The APBT provides a stable time base on SMP
630 systems, unlike the TSC, but it is more expensive to access,
631 as it is off-chip. APB timers are always running regardless of CPU
632 C states, they are used as per CPU clockevent device when possible.
634 # Mark as expert because too many people got it wrong.
635 # The code disables itself when not needed.
638 bool "Enable DMI scanning" if EXPERT
640 Enabled scanning of DMI to identify machine quirks. Say Y
641 here unless you have verified that your setup is not
642 affected by entries in the DMI blacklist. Required by PNP
646 bool "GART IOMMU support" if EXPERT
649 depends on X86_64 && PCI && AMD_NB
651 Support for full DMA access of devices with 32bit memory access only
652 on systems with more than 3GB. This is usually needed for USB,
653 sound, many IDE/SATA chipsets and some other devices.
654 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
655 based hardware IOMMU and a software bounce buffer based IOMMU used
656 on Intel systems and as fallback.
657 The code is only active when needed (enough memory and limited
658 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
662 bool "IBM Calgary IOMMU support"
664 depends on X86_64 && PCI && EXPERIMENTAL
666 Support for hardware IOMMUs in IBM's xSeries x366 and x460
667 systems. Needed to run systems with more than 3GB of memory
668 properly with 32-bit PCI devices that do not support DAC
669 (Double Address Cycle). Calgary also supports bus level
670 isolation, where all DMAs pass through the IOMMU. This
671 prevents them from going anywhere except their intended
672 destination. This catches hard-to-find kernel bugs and
673 mis-behaving drivers and devices that do not use the DMA-API
674 properly to set up their DMA buffers. The IOMMU can be
675 turned off at boot time with the iommu=off parameter.
676 Normally the kernel will make the right choice by itself.
679 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
681 prompt "Should Calgary be enabled by default?"
682 depends on CALGARY_IOMMU
684 Should Calgary be enabled by default? if you choose 'y', Calgary
685 will be used (if it exists). If you choose 'n', Calgary will not be
686 used even if it exists. If you choose 'n' and would like to use
687 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
690 # need this always selected by IOMMU for the VIA workaround
694 Support for software bounce buffers used on x86-64 systems
695 which don't have a hardware IOMMU (e.g. the current generation
696 of Intel's x86-64 CPUs). Using this PCI devices which can only
697 access 32-bits of memory can be used on systems with more than
698 3 GB of memory. If unsure, say Y.
701 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
704 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
705 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
706 select CPUMASK_OFFSTACK
708 Enable maximum number of CPUS and NUMA Nodes for this architecture.
712 int "Maximum number of CPUs" if SMP && !MAXSMP
713 range 2 8 if SMP && X86_32 && !X86_BIGSMP
714 range 2 512 if SMP && !MAXSMP
716 default "4096" if MAXSMP
717 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
720 This allows you to specify the maximum number of CPUs which this
721 kernel will support. The maximum supported value is 512 and the
722 minimum value which makes sense is 2.
724 This is purely to save memory - each supported CPU adds
725 approximately eight kilobytes to the kernel image.
728 bool "SMT (Hyperthreading) scheduler support"
731 SMT scheduler support improves the CPU scheduler's decision making
732 when dealing with Intel Pentium 4 chips with HyperThreading at a
733 cost of slightly increased overhead in some places. If unsure say
738 prompt "Multi-core scheduler support"
741 Multi-core scheduler support improves the CPU scheduler's decision
742 making when dealing with multi-core CPU chips at a cost of slightly
743 increased overhead in some places. If unsure say N here.
745 config IRQ_TIME_ACCOUNTING
746 bool "Fine granularity task level IRQ time accounting"
749 Select this option to enable fine granularity task irq time
750 accounting. This is done by reading a timestamp on each
751 transitions between softirq and hardirq state, so there can be a
752 small performance impact.
754 If in doubt, say N here.
756 source "kernel/Kconfig.preempt"
759 bool "Local APIC support on uniprocessors"
760 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
762 A local APIC (Advanced Programmable Interrupt Controller) is an
763 integrated interrupt controller in the CPU. If you have a single-CPU
764 system which has a processor with a local APIC, you can say Y here to
765 enable and use it. If you say Y here even though your machine doesn't
766 have a local APIC, then the kernel will still run with no slowdown at
767 all. The local APIC supports CPU-generated self-interrupts (timer,
768 performance counters), and the NMI watchdog which detects hard
772 bool "IO-APIC support on uniprocessors"
773 depends on X86_UP_APIC
775 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
776 SMP-capable replacement for PC-style interrupt controllers. Most
777 SMP systems and many recent uniprocessor systems have one.
779 If you have a single-CPU system with an IO-APIC, you can say Y here
780 to use it. If you say Y here even though your machine doesn't have
781 an IO-APIC, then the kernel will still run with no slowdown at all.
783 config X86_LOCAL_APIC
785 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
789 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
791 config X86_VISWS_APIC
793 depends on X86_32 && X86_VISWS
795 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
796 bool "Reroute for broken boot IRQs"
797 depends on X86_IO_APIC
799 This option enables a workaround that fixes a source of
800 spurious interrupts. This is recommended when threaded
801 interrupt handling is used on systems where the generation of
802 superfluous "boot interrupts" cannot be disabled.
804 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
805 entry in the chipset's IO-APIC is masked (as, e.g. the RT
806 kernel does during interrupt handling). On chipsets where this
807 boot IRQ generation cannot be disabled, this workaround keeps
808 the original IRQ line masked so that only the equivalent "boot
809 IRQ" is delivered to the CPUs. The workaround also tells the
810 kernel to set up the IRQ handler on the boot IRQ line. In this
811 way only one interrupt is delivered to the kernel. Otherwise
812 the spurious second interrupt may cause the kernel to bring
813 down (vital) interrupt lines.
815 Only affects "broken" chipsets. Interrupt sharing may be
816 increased on these systems.
819 bool "Machine Check / overheating reporting"
821 Machine Check support allows the processor to notify the
822 kernel if it detects a problem (e.g. overheating, data corruption).
823 The action the kernel takes depends on the severity of the problem,
824 ranging from warning messages to halting the machine.
828 prompt "Intel MCE features"
829 depends on X86_MCE && X86_LOCAL_APIC
831 Additional support for intel specific MCE features such as
836 prompt "AMD MCE features"
837 depends on X86_MCE && X86_LOCAL_APIC
839 Additional support for AMD specific MCE features such as
840 the DRAM Error Threshold.
842 config X86_ANCIENT_MCE
843 bool "Support for old Pentium 5 / WinChip machine checks"
844 depends on X86_32 && X86_MCE
846 Include support for machine check handling on old Pentium 5 or WinChip
847 systems. These typically need to be enabled explicitely on the command
850 config X86_MCE_THRESHOLD
851 depends on X86_MCE_AMD || X86_MCE_INTEL
854 config X86_MCE_INJECT
856 tristate "Machine check injector support"
858 Provide support for injecting machine checks for testing purposes.
859 If you don't know what a machine check is and you don't do kernel
860 QA it is safe to say n.
862 config X86_THERMAL_VECTOR
864 depends on X86_MCE_INTEL
867 bool "Enable VM86 support" if EXPERT
871 This option is required by programs like DOSEMU to run 16-bit legacy
872 code on X86 processors. It also may be needed by software like
873 XFree86 to initialize some video cards via BIOS. Disabling this
874 option saves about 6k.
877 tristate "Toshiba Laptop support"
880 This adds a driver to safely access the System Management Mode of
881 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
882 not work on models with a Phoenix BIOS. The System Management Mode
883 is used to set the BIOS and power saving options on Toshiba portables.
885 For information on utilities to make use of this driver see the
886 Toshiba Linux utilities web site at:
887 <http://www.buzzard.org.uk/toshiba/>.
889 Say Y if you intend to run this kernel on a Toshiba portable.
893 tristate "Dell laptop support"
896 This adds a driver to safely access the System Management Mode
897 of the CPU on the Dell Inspiron 8000. The System Management Mode
898 is used to read cpu temperature and cooling fan status and to
899 control the fans on the I8K portables.
901 This driver has been tested only on the Inspiron 8000 but it may
902 also work with other Dell laptops. You can force loading on other
903 models by passing the parameter `force=1' to the module. Use at
906 For information on utilities to make use of this driver see the
907 I8K Linux utilities web site at:
908 <http://people.debian.org/~dz/i8k/>
910 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
913 config X86_REBOOTFIXUPS
914 bool "Enable X86 board specific fixups for reboot"
917 This enables chipset and/or board specific fixups to be done
918 in order to get reboot to work correctly. This is only needed on
919 some combinations of hardware and BIOS. The symptom, for which
920 this config is intended, is when reboot ends with a stalled/hung
923 Currently, the only fixup is for the Geode machines using
924 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
926 Say Y if you want to enable the fixup. Currently, it's safe to
927 enable this option even if you don't need it.
931 tristate "/dev/cpu/microcode - microcode support"
934 If you say Y here, you will be able to update the microcode on
935 certain Intel and AMD processors. The Intel support is for the
936 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
937 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
938 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
939 You will obviously need the actual microcode binary data itself
940 which is not shipped with the Linux kernel.
942 This option selects the general module only, you need to select
943 at least one vendor specific module as well.
945 To compile this driver as a module, choose M here: the
946 module will be called microcode.
948 config MICROCODE_INTEL
949 bool "Intel microcode patch loading support"
954 This options enables microcode patch loading support for Intel
957 For latest news and information on obtaining all the required
958 Intel ingredients for this driver, check:
959 <http://www.urbanmyth.org/microcode/>.
962 bool "AMD microcode patch loading support"
966 If you select this option, microcode patch loading support for AMD
967 processors will be enabled.
969 config MICROCODE_OLD_INTERFACE
974 tristate "/dev/cpu/*/msr - Model-specific register support"
976 This device gives privileged processes access to the x86
977 Model-Specific Registers (MSRs). It is a character device with
978 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
979 MSR accesses are directed to a specific CPU on multi-processor
983 tristate "/dev/cpu/*/cpuid - CPU information support"
985 This device gives processes access to the x86 CPUID instruction to
986 be executed on a specific processor. It is a character device
987 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
991 prompt "High Memory Support"
992 default HIGHMEM64G if X86_NUMAQ
998 depends on !X86_NUMAQ
1000 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1001 However, the address space of 32-bit x86 processors is only 4
1002 Gigabytes large. That means that, if you have a large amount of
1003 physical memory, not all of it can be "permanently mapped" by the
1004 kernel. The physical memory that's not permanently mapped is called
1007 If you are compiling a kernel which will never run on a machine with
1008 more than 1 Gigabyte total physical RAM, answer "off" here (default
1009 choice and suitable for most users). This will result in a "3GB/1GB"
1010 split: 3GB are mapped so that each process sees a 3GB virtual memory
1011 space and the remaining part of the 4GB virtual memory space is used
1012 by the kernel to permanently map as much physical memory as
1015 If the machine has between 1 and 4 Gigabytes physical RAM, then
1018 If more than 4 Gigabytes is used then answer "64GB" here. This
1019 selection turns Intel PAE (Physical Address Extension) mode on.
1020 PAE implements 3-level paging on IA32 processors. PAE is fully
1021 supported by Linux, PAE mode is implemented on all recent Intel
1022 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1023 then the kernel will not boot on CPUs that don't support PAE!
1025 The actual amount of total physical memory will either be
1026 auto detected or can be forced by using a kernel command line option
1027 such as "mem=256M". (Try "man bootparam" or see the documentation of
1028 your boot loader (lilo or loadlin) about how to pass options to the
1029 kernel at boot time.)
1031 If unsure, say "off".
1035 depends on !X86_NUMAQ
1037 Select this if you have a 32-bit processor and between 1 and 4
1038 gigabytes of physical RAM.
1042 depends on !M386 && !M486
1045 Select this if you have a 32-bit processor and more than 4
1046 gigabytes of physical RAM.
1051 depends on EXPERIMENTAL
1052 prompt "Memory split" if EXPERT
1056 Select the desired split between kernel and user memory.
1058 If the address range available to the kernel is less than the
1059 physical memory installed, the remaining memory will be available
1060 as "high memory". Accessing high memory is a little more costly
1061 than low memory, as it needs to be mapped into the kernel first.
1062 Note that increasing the kernel address space limits the range
1063 available to user programs, making the address space there
1064 tighter. Selecting anything other than the default 3G/1G split
1065 will also likely make your kernel incompatible with binary-only
1068 If you are not absolutely sure what you are doing, leave this
1072 bool "3G/1G user/kernel split"
1073 config VMSPLIT_3G_OPT
1075 bool "3G/1G user/kernel split (for full 1G low memory)"
1077 bool "2G/2G user/kernel split"
1078 config VMSPLIT_2G_OPT
1080 bool "2G/2G user/kernel split (for full 2G low memory)"
1082 bool "1G/3G user/kernel split"
1087 default 0xB0000000 if VMSPLIT_3G_OPT
1088 default 0x80000000 if VMSPLIT_2G
1089 default 0x78000000 if VMSPLIT_2G_OPT
1090 default 0x40000000 if VMSPLIT_1G
1096 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1099 bool "PAE (Physical Address Extension) Support"
1100 depends on X86_32 && !HIGHMEM4G
1102 PAE is required for NX support, and furthermore enables
1103 larger swapspace support for non-overcommit purposes. It
1104 has the cost of more pagetable lookup overhead, and also
1105 consumes more pagetable space per process.
1107 config ARCH_PHYS_ADDR_T_64BIT
1108 def_bool X86_64 || X86_PAE
1110 config ARCH_DMA_ADDR_T_64BIT
1111 def_bool X86_64 || HIGHMEM64G
1113 config DIRECT_GBPAGES
1114 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1118 Allow the kernel linear mapping to use 1GB pages on CPUs that
1119 support it. This can improve the kernel's performance a tiny bit by
1120 reducing TLB pressure. If in doubt, say "Y".
1122 # Common NUMA Features
1124 bool "Numa Memory Allocation and Scheduler Support"
1126 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1127 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1129 Enable NUMA (Non Uniform Memory Access) support.
1131 The kernel will try to allocate memory used by a CPU on the
1132 local memory controller of the CPU and add some more
1133 NUMA awareness to the kernel.
1135 For 64-bit this is recommended if the system is Intel Core i7
1136 (or later), AMD Opteron, or EM64T NUMA.
1138 For 32-bit this is only needed on (rare) 32-bit-only platforms
1139 that support NUMA topologies, such as NUMAQ / Summit, or if you
1140 boot a 32-bit kernel on a 64-bit NUMA platform.
1142 Otherwise, you should say N.
1144 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1145 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1149 prompt "Old style AMD Opteron NUMA detection"
1150 depends on X86_64 && NUMA && PCI
1152 Enable AMD NUMA node topology detection. You should say Y here if
1153 you have a multi processor AMD system. This uses an old method to
1154 read the NUMA configuration directly from the builtin Northbridge
1155 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1156 which also takes priority if both are compiled in.
1158 config X86_64_ACPI_NUMA
1160 prompt "ACPI NUMA detection"
1161 depends on X86_64 && NUMA && ACPI && PCI
1164 Enable ACPI SRAT based node topology detection.
1166 # Some NUMA nodes have memory ranges that span
1167 # other nodes. Even though a pfn is valid and
1168 # between a node's start and end pfns, it may not
1169 # reside on that node. See memmap_init_zone()
1171 config NODES_SPAN_OTHER_NODES
1173 depends on X86_64_ACPI_NUMA
1176 bool "NUMA emulation"
1179 Enable NUMA emulation. A flat machine will be split
1180 into virtual nodes when booted with "numa=fake=N", where N is the
1181 number of nodes. This is only useful for debugging.
1184 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1186 default "10" if MAXSMP
1187 default "6" if X86_64
1188 default "4" if X86_NUMAQ
1190 depends on NEED_MULTIPLE_NODES
1192 Specify the maximum number of NUMA Nodes available on the target
1193 system. Increases memory reserved to accommodate various tables.
1195 config HAVE_ARCH_BOOTMEM
1197 depends on X86_32 && NUMA
1199 config HAVE_ARCH_ALLOC_REMAP
1201 depends on X86_32 && NUMA
1203 config ARCH_HAVE_MEMORY_PRESENT
1205 depends on X86_32 && DISCONTIGMEM
1207 config NEED_NODE_MEMMAP_SIZE
1209 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1211 config ARCH_FLATMEM_ENABLE
1213 depends on X86_32 && !NUMA
1215 config ARCH_DISCONTIGMEM_ENABLE
1217 depends on NUMA && X86_32
1219 config ARCH_DISCONTIGMEM_DEFAULT
1221 depends on NUMA && X86_32
1223 config ARCH_SPARSEMEM_ENABLE
1225 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1226 select SPARSEMEM_STATIC if X86_32
1227 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1229 config ARCH_SPARSEMEM_DEFAULT
1233 config ARCH_SELECT_MEMORY_MODEL
1235 depends on ARCH_SPARSEMEM_ENABLE
1237 config ARCH_MEMORY_PROBE
1239 depends on MEMORY_HOTPLUG
1241 config ARCH_PROC_KCORE_TEXT
1243 depends on X86_64 && PROC_KCORE
1245 config ILLEGAL_POINTER_VALUE
1248 default 0xdead000000000000 if X86_64
1253 bool "Allocate 3rd-level pagetables from highmem"
1256 The VM uses one page table entry for each page of physical memory.
1257 For systems with a lot of RAM, this can be wasteful of precious
1258 low memory. Setting this option will put user-space page table
1259 entries in high memory.
1261 config X86_CHECK_BIOS_CORRUPTION
1262 bool "Check for low memory corruption"
1264 Periodically check for memory corruption in low memory, which
1265 is suspected to be caused by BIOS. Even when enabled in the
1266 configuration, it is disabled at runtime. Enable it by
1267 setting "memory_corruption_check=1" on the kernel command
1268 line. By default it scans the low 64k of memory every 60
1269 seconds; see the memory_corruption_check_size and
1270 memory_corruption_check_period parameters in
1271 Documentation/kernel-parameters.txt to adjust this.
1273 When enabled with the default parameters, this option has
1274 almost no overhead, as it reserves a relatively small amount
1275 of memory and scans it infrequently. It both detects corruption
1276 and prevents it from affecting the running system.
1278 It is, however, intended as a diagnostic tool; if repeatable
1279 BIOS-originated corruption always affects the same memory,
1280 you can use memmap= to prevent the kernel from using that
1283 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1284 bool "Set the default setting of memory_corruption_check"
1285 depends on X86_CHECK_BIOS_CORRUPTION
1288 Set whether the default state of memory_corruption_check is
1291 config X86_RESERVE_LOW
1292 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1296 Specify the amount of low memory to reserve for the BIOS.
1298 The first page contains BIOS data structures that the kernel
1299 must not use, so that page must always be reserved.
1301 By default we reserve the first 64K of physical RAM, as a
1302 number of BIOSes are known to corrupt that memory range
1303 during events such as suspend/resume or monitor cable
1304 insertion, so it must not be used by the kernel.
1306 You can set this to 4 if you are absolutely sure that you
1307 trust the BIOS to get all its memory reservations and usages
1308 right. If you know your BIOS have problems beyond the
1309 default 64K area, you can set this to 640 to avoid using the
1310 entire low memory range.
1312 If you have doubts about the BIOS (e.g. suspend/resume does
1313 not work or there's kernel crashes after certain hardware
1314 hotplug events) then you might want to enable
1315 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1316 typical corruption patterns.
1318 Leave this to the default value of 64 if you are unsure.
1320 config MATH_EMULATION
1322 prompt "Math emulation" if X86_32
1324 Linux can emulate a math coprocessor (used for floating point
1325 operations) if you don't have one. 486DX and Pentium processors have
1326 a math coprocessor built in, 486SX and 386 do not, unless you added
1327 a 487DX or 387, respectively. (The messages during boot time can
1328 give you some hints here ["man dmesg"].) Everyone needs either a
1329 coprocessor or this emulation.
1331 If you don't have a math coprocessor, you need to say Y here; if you
1332 say Y here even though you have a coprocessor, the coprocessor will
1333 be used nevertheless. (This behavior can be changed with the kernel
1334 command line option "no387", which comes handy if your coprocessor
1335 is broken. Try "man bootparam" or see the documentation of your boot
1336 loader (lilo or loadlin) about how to pass options to the kernel at
1337 boot time.) This means that it is a good idea to say Y here if you
1338 intend to use this kernel on different machines.
1340 More information about the internals of the Linux math coprocessor
1341 emulation can be found in <file:arch/x86/math-emu/README>.
1343 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1344 kernel, it won't hurt.
1348 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1350 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1351 the Memory Type Range Registers (MTRRs) may be used to control
1352 processor access to memory ranges. This is most useful if you have
1353 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1354 allows bus write transfers to be combined into a larger transfer
1355 before bursting over the PCI/AGP bus. This can increase performance
1356 of image write operations 2.5 times or more. Saying Y here creates a
1357 /proc/mtrr file which may be used to manipulate your processor's
1358 MTRRs. Typically the X server should use this.
1360 This code has a reasonably generic interface so that similar
1361 control registers on other processors can be easily supported
1364 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1365 Registers (ARRs) which provide a similar functionality to MTRRs. For
1366 these, the ARRs are used to emulate the MTRRs.
1367 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1368 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1369 write-combining. All of these processors are supported by this code
1370 and it makes sense to say Y here if you have one of them.
1372 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1373 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1374 can lead to all sorts of problems, so it's good to say Y here.
1376 You can safely say Y even if your machine doesn't have MTRRs, you'll
1377 just add about 9 KB to your kernel.
1379 See <file:Documentation/x86/mtrr.txt> for more information.
1381 config MTRR_SANITIZER
1383 prompt "MTRR cleanup support"
1386 Convert MTRR layout from continuous to discrete, so X drivers can
1387 add writeback entries.
1389 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1390 The largest mtrr entry size for a continuous block can be set with
1395 config MTRR_SANITIZER_ENABLE_DEFAULT
1396 int "MTRR cleanup enable value (0-1)"
1399 depends on MTRR_SANITIZER
1401 Enable mtrr cleanup default value
1403 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1404 int "MTRR cleanup spare reg num (0-7)"
1407 depends on MTRR_SANITIZER
1409 mtrr cleanup spare entries default, it can be changed via
1410 mtrr_spare_reg_nr=N on the kernel command line.
1414 prompt "x86 PAT support" if EXPERT
1417 Use PAT attributes to setup page level cache control.
1419 PATs are the modern equivalents of MTRRs and are much more
1420 flexible than MTRRs.
1422 Say N here if you see bootup problems (boot crash, boot hang,
1423 spontaneous reboots) or a non-working video driver.
1427 config ARCH_USES_PG_UNCACHED
1432 bool "EFI runtime service support"
1435 This enables the kernel to use EFI runtime services that are
1436 available (such as the EFI variable services).
1438 This option is only useful on systems that have EFI firmware.
1439 In addition, you should use the latest ELILO loader available
1440 at <http://elilo.sourceforge.net> in order to take advantage
1441 of EFI runtime services. However, even with this option, the
1442 resultant kernel should continue to boot on existing non-EFI
1447 prompt "Enable seccomp to safely compute untrusted bytecode"
1449 This kernel feature is useful for number crunching applications
1450 that may need to compute untrusted bytecode during their
1451 execution. By using pipes or other transports made available to
1452 the process as file descriptors supporting the read/write
1453 syscalls, it's possible to isolate those applications in
1454 their own address space using seccomp. Once seccomp is
1455 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1456 and the task is only allowed to execute a few safe syscalls
1457 defined by each seccomp mode.
1459 If unsure, say Y. Only embedded should say N here.
1461 config CC_STACKPROTECTOR
1462 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1464 This option turns on the -fstack-protector GCC feature. This
1465 feature puts, at the beginning of functions, a canary value on
1466 the stack just before the return address, and validates
1467 the value just before actually returning. Stack based buffer
1468 overflows (that need to overwrite this return address) now also
1469 overwrite the canary, which gets detected and the attack is then
1470 neutralized via a kernel panic.
1472 This feature requires gcc version 4.2 or above, or a distribution
1473 gcc with the feature backported. Older versions are automatically
1474 detected and for those versions, this configuration option is
1475 ignored. (and a warning is printed during bootup)
1477 source kernel/Kconfig.hz
1480 bool "kexec system call"
1482 kexec is a system call that implements the ability to shutdown your
1483 current kernel, and to start another kernel. It is like a reboot
1484 but it is independent of the system firmware. And like a reboot
1485 you can start any kernel with it, not just Linux.
1487 The name comes from the similarity to the exec system call.
1489 It is an ongoing process to be certain the hardware in a machine
1490 is properly shutdown, so do not be surprised if this code does not
1491 initially work for you. It may help to enable device hotplugging
1492 support. As of this writing the exact hardware interface is
1493 strongly in flux, so no good recommendation can be made.
1496 bool "kernel crash dumps"
1497 depends on X86_64 || (X86_32 && HIGHMEM)
1499 Generate crash dump after being started by kexec.
1500 This should be normally only set in special crash dump kernels
1501 which are loaded in the main kernel with kexec-tools into
1502 a specially reserved region and then later executed after
1503 a crash by kdump/kexec. The crash dump kernel must be compiled
1504 to a memory address not used by the main kernel or BIOS using
1505 PHYSICAL_START, or it must be built as a relocatable image
1506 (CONFIG_RELOCATABLE=y).
1507 For more details see Documentation/kdump/kdump.txt
1510 bool "kexec jump (EXPERIMENTAL)"
1511 depends on EXPERIMENTAL
1512 depends on KEXEC && HIBERNATION
1514 Jump between original kernel and kexeced kernel and invoke
1515 code in physical address mode via KEXEC
1517 config PHYSICAL_START
1518 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1521 This gives the physical address where the kernel is loaded.
1523 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1524 bzImage will decompress itself to above physical address and
1525 run from there. Otherwise, bzImage will run from the address where
1526 it has been loaded by the boot loader and will ignore above physical
1529 In normal kdump cases one does not have to set/change this option
1530 as now bzImage can be compiled as a completely relocatable image
1531 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1532 address. This option is mainly useful for the folks who don't want
1533 to use a bzImage for capturing the crash dump and want to use a
1534 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1535 to be specifically compiled to run from a specific memory area
1536 (normally a reserved region) and this option comes handy.
1538 So if you are using bzImage for capturing the crash dump,
1539 leave the value here unchanged to 0x1000000 and set
1540 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1541 for capturing the crash dump change this value to start of
1542 the reserved region. In other words, it can be set based on
1543 the "X" value as specified in the "crashkernel=YM@XM"
1544 command line boot parameter passed to the panic-ed
1545 kernel. Please take a look at Documentation/kdump/kdump.txt
1546 for more details about crash dumps.
1548 Usage of bzImage for capturing the crash dump is recommended as
1549 one does not have to build two kernels. Same kernel can be used
1550 as production kernel and capture kernel. Above option should have
1551 gone away after relocatable bzImage support is introduced. But it
1552 is present because there are users out there who continue to use
1553 vmlinux for dump capture. This option should go away down the
1556 Don't change this unless you know what you are doing.
1559 bool "Build a relocatable kernel"
1562 This builds a kernel image that retains relocation information
1563 so it can be loaded someplace besides the default 1MB.
1564 The relocations tend to make the kernel binary about 10% larger,
1565 but are discarded at runtime.
1567 One use is for the kexec on panic case where the recovery kernel
1568 must live at a different physical address than the primary
1571 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1572 it has been loaded at and the compile time physical address
1573 (CONFIG_PHYSICAL_START) is ignored.
1575 # Relocation on x86-32 needs some additional build support
1576 config X86_NEED_RELOCS
1578 depends on X86_32 && RELOCATABLE
1580 config PHYSICAL_ALIGN
1581 hex "Alignment value to which kernel should be aligned" if X86_32
1583 range 0x2000 0x1000000
1585 This value puts the alignment restrictions on physical address
1586 where kernel is loaded and run from. Kernel is compiled for an
1587 address which meets above alignment restriction.
1589 If bootloader loads the kernel at a non-aligned address and
1590 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1591 address aligned to above value and run from there.
1593 If bootloader loads the kernel at a non-aligned address and
1594 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1595 load address and decompress itself to the address it has been
1596 compiled for and run from there. The address for which kernel is
1597 compiled already meets above alignment restrictions. Hence the
1598 end result is that kernel runs from a physical address meeting
1599 above alignment restrictions.
1601 Don't change this unless you know what you are doing.
1604 bool "Support for hot-pluggable CPUs"
1605 depends on SMP && HOTPLUG
1607 Say Y here to allow turning CPUs off and on. CPUs can be
1608 controlled through /sys/devices/system/cpu.
1609 ( Note: power management support will enable this option
1610 automatically on SMP systems. )
1611 Say N if you want to disable CPU hotplug.
1615 prompt "Compat VDSO support"
1616 depends on X86_32 || IA32_EMULATION
1618 Map the 32-bit VDSO to the predictable old-style address too.
1620 Say N here if you are running a sufficiently recent glibc
1621 version (2.3.3 or later), to remove the high-mapped
1622 VDSO mapping and to exclusively use the randomized VDSO.
1627 bool "Built-in kernel command line"
1629 Allow for specifying boot arguments to the kernel at
1630 build time. On some systems (e.g. embedded ones), it is
1631 necessary or convenient to provide some or all of the
1632 kernel boot arguments with the kernel itself (that is,
1633 to not rely on the boot loader to provide them.)
1635 To compile command line arguments into the kernel,
1636 set this option to 'Y', then fill in the
1637 the boot arguments in CONFIG_CMDLINE.
1639 Systems with fully functional boot loaders (i.e. non-embedded)
1640 should leave this option set to 'N'.
1643 string "Built-in kernel command string"
1644 depends on CMDLINE_BOOL
1647 Enter arguments here that should be compiled into the kernel
1648 image and used at boot time. If the boot loader provides a
1649 command line at boot time, it is appended to this string to
1650 form the full kernel command line, when the system boots.
1652 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1653 change this behavior.
1655 In most cases, the command line (whether built-in or provided
1656 by the boot loader) should specify the device for the root
1659 config CMDLINE_OVERRIDE
1660 bool "Built-in command line overrides boot loader arguments"
1661 depends on CMDLINE_BOOL
1663 Set this option to 'Y' to have the kernel ignore the boot loader
1664 command line, and use ONLY the built-in command line.
1666 This is used to work around broken boot loaders. This should
1667 be set to 'N' under normal conditions.
1671 config ARCH_ENABLE_MEMORY_HOTPLUG
1673 depends on X86_64 || (X86_32 && HIGHMEM)
1675 config ARCH_ENABLE_MEMORY_HOTREMOVE
1677 depends on MEMORY_HOTPLUG
1679 config USE_PERCPU_NUMA_NODE_ID
1683 menu "Power management and ACPI options"
1685 config ARCH_HIBERNATION_HEADER
1687 depends on X86_64 && HIBERNATION
1689 source "kernel/power/Kconfig"
1691 source "drivers/acpi/Kconfig"
1693 source "drivers/sfi/Kconfig"
1697 depends on APM || APM_MODULE
1700 tristate "APM (Advanced Power Management) BIOS support"
1701 depends on X86_32 && PM_SLEEP
1703 APM is a BIOS specification for saving power using several different
1704 techniques. This is mostly useful for battery powered laptops with
1705 APM compliant BIOSes. If you say Y here, the system time will be
1706 reset after a RESUME operation, the /proc/apm device will provide
1707 battery status information, and user-space programs will receive
1708 notification of APM "events" (e.g. battery status change).
1710 If you select "Y" here, you can disable actual use of the APM
1711 BIOS by passing the "apm=off" option to the kernel at boot time.
1713 Note that the APM support is almost completely disabled for
1714 machines with more than one CPU.
1716 In order to use APM, you will need supporting software. For location
1717 and more information, read <file:Documentation/power/pm.txt> and the
1718 Battery Powered Linux mini-HOWTO, available from
1719 <http://www.tldp.org/docs.html#howto>.
1721 This driver does not spin down disk drives (see the hdparm(8)
1722 manpage ("man 8 hdparm") for that), and it doesn't turn off
1723 VESA-compliant "green" monitors.
1725 This driver does not support the TI 4000M TravelMate and the ACER
1726 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1727 desktop machines also don't have compliant BIOSes, and this driver
1728 may cause those machines to panic during the boot phase.
1730 Generally, if you don't have a battery in your machine, there isn't
1731 much point in using this driver and you should say N. If you get
1732 random kernel OOPSes or reboots that don't seem to be related to
1733 anything, try disabling/enabling this option (or disabling/enabling
1736 Some other things you should try when experiencing seemingly random,
1739 1) make sure that you have enough swap space and that it is
1741 2) pass the "no-hlt" option to the kernel
1742 3) switch on floating point emulation in the kernel and pass
1743 the "no387" option to the kernel
1744 4) pass the "floppy=nodma" option to the kernel
1745 5) pass the "mem=4M" option to the kernel (thereby disabling
1746 all but the first 4 MB of RAM)
1747 6) make sure that the CPU is not over clocked.
1748 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1749 8) disable the cache from your BIOS settings
1750 9) install a fan for the video card or exchange video RAM
1751 10) install a better fan for the CPU
1752 11) exchange RAM chips
1753 12) exchange the motherboard.
1755 To compile this driver as a module, choose M here: the
1756 module will be called apm.
1760 config APM_IGNORE_USER_SUSPEND
1761 bool "Ignore USER SUSPEND"
1763 This option will ignore USER SUSPEND requests. On machines with a
1764 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1765 series notebooks, it is necessary to say Y because of a BIOS bug.
1767 config APM_DO_ENABLE
1768 bool "Enable PM at boot time"
1770 Enable APM features at boot time. From page 36 of the APM BIOS
1771 specification: "When disabled, the APM BIOS does not automatically
1772 power manage devices, enter the Standby State, enter the Suspend
1773 State, or take power saving steps in response to CPU Idle calls."
1774 This driver will make CPU Idle calls when Linux is idle (unless this
1775 feature is turned off -- see "Do CPU IDLE calls", below). This
1776 should always save battery power, but more complicated APM features
1777 will be dependent on your BIOS implementation. You may need to turn
1778 this option off if your computer hangs at boot time when using APM
1779 support, or if it beeps continuously instead of suspending. Turn
1780 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1781 T400CDT. This is off by default since most machines do fine without
1785 bool "Make CPU Idle calls when idle"
1787 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1788 On some machines, this can activate improved power savings, such as
1789 a slowed CPU clock rate, when the machine is idle. These idle calls
1790 are made after the idle loop has run for some length of time (e.g.,
1791 333 mS). On some machines, this will cause a hang at boot time or
1792 whenever the CPU becomes idle. (On machines with more than one CPU,
1793 this option does nothing.)
1795 config APM_DISPLAY_BLANK
1796 bool "Enable console blanking using APM"
1798 Enable console blanking using the APM. Some laptops can use this to
1799 turn off the LCD backlight when the screen blanker of the Linux
1800 virtual console blanks the screen. Note that this is only used by
1801 the virtual console screen blanker, and won't turn off the backlight
1802 when using the X Window system. This also doesn't have anything to
1803 do with your VESA-compliant power-saving monitor. Further, this
1804 option doesn't work for all laptops -- it might not turn off your
1805 backlight at all, or it might print a lot of errors to the console,
1806 especially if you are using gpm.
1808 config APM_ALLOW_INTS
1809 bool "Allow interrupts during APM BIOS calls"
1811 Normally we disable external interrupts while we are making calls to
1812 the APM BIOS as a measure to lessen the effects of a badly behaving
1813 BIOS implementation. The BIOS should reenable interrupts if it
1814 needs to. Unfortunately, some BIOSes do not -- especially those in
1815 many of the newer IBM Thinkpads. If you experience hangs when you
1816 suspend, try setting this to Y. Otherwise, say N.
1820 source "drivers/cpufreq/Kconfig"
1822 source "drivers/cpuidle/Kconfig"
1824 source "drivers/idle/Kconfig"
1829 menu "Bus options (PCI etc.)"
1834 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1836 Find out whether you have a PCI motherboard. PCI is the name of a
1837 bus system, i.e. the way the CPU talks to the other stuff inside
1838 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1839 VESA. If you have PCI, say Y, otherwise N.
1842 prompt "PCI access mode"
1843 depends on X86_32 && PCI
1846 On PCI systems, the BIOS can be used to detect the PCI devices and
1847 determine their configuration. However, some old PCI motherboards
1848 have BIOS bugs and may crash if this is done. Also, some embedded
1849 PCI-based systems don't have any BIOS at all. Linux can also try to
1850 detect the PCI hardware directly without using the BIOS.
1852 With this option, you can specify how Linux should detect the
1853 PCI devices. If you choose "BIOS", the BIOS will be used,
1854 if you choose "Direct", the BIOS won't be used, and if you
1855 choose "MMConfig", then PCI Express MMCONFIG will be used.
1856 If you choose "Any", the kernel will try MMCONFIG, then the
1857 direct access method and falls back to the BIOS if that doesn't
1858 work. If unsure, go with the default, which is "Any".
1863 config PCI_GOMMCONFIG
1880 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1882 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1885 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1889 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1893 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1897 depends on PCI && XEN
1905 bool "Support mmconfig PCI config space access"
1906 depends on X86_64 && PCI && ACPI
1908 config PCI_CNB20LE_QUIRK
1909 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1911 depends on PCI && EXPERIMENTAL
1913 Read the PCI windows out of the CNB20LE host bridge. This allows
1914 PCI hotplug to work on systems with the CNB20LE chipset which do
1917 There's no public spec for this chipset, and this functionality
1918 is known to be incomplete.
1920 You should say N unless you know you need this.
1922 source "drivers/pci/pcie/Kconfig"
1924 source "drivers/pci/Kconfig"
1926 # x86_64 have no ISA slots, but can have ISA-style DMA.
1928 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1931 Enables ISA-style DMA support for devices requiring such controllers.
1939 Find out whether you have ISA slots on your motherboard. ISA is the
1940 name of a bus system, i.e. the way the CPU talks to the other stuff
1941 inside your box. Other bus systems are PCI, EISA, MicroChannel
1942 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1943 newer boards don't support it. If you have ISA, say Y, otherwise N.
1949 The Extended Industry Standard Architecture (EISA) bus was
1950 developed as an open alternative to the IBM MicroChannel bus.
1952 The EISA bus provided some of the features of the IBM MicroChannel
1953 bus while maintaining backward compatibility with cards made for
1954 the older ISA bus. The EISA bus saw limited use between 1988 and
1955 1995 when it was made obsolete by the PCI bus.
1957 Say Y here if you are building a kernel for an EISA-based machine.
1961 source "drivers/eisa/Kconfig"
1966 MicroChannel Architecture is found in some IBM PS/2 machines and
1967 laptops. It is a bus system similar to PCI or ISA. See
1968 <file:Documentation/mca.txt> (and especially the web page given
1969 there) before attempting to build an MCA bus kernel.
1971 source "drivers/mca/Kconfig"
1974 tristate "NatSemi SCx200 support"
1976 This provides basic support for National Semiconductor's
1977 (now AMD's) Geode processors. The driver probes for the
1978 PCI-IDs of several on-chip devices, so its a good dependency
1979 for other scx200_* drivers.
1981 If compiled as a module, the driver is named scx200.
1983 config SCx200HR_TIMER
1984 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1988 This driver provides a clocksource built upon the on-chip
1989 27MHz high-resolution timer. Its also a workaround for
1990 NSC Geode SC-1100's buggy TSC, which loses time when the
1991 processor goes idle (as is done by the scheduler). The
1992 other workaround is idle=poll boot option.
1995 bool "One Laptop Per Child support"
2001 Add support for detecting the unique features of the OLPC
2005 tristate "OLPC XO-1 support"
2006 depends on OLPC && MFD_CS5535
2008 Add support for non-essential features of the OLPC XO-1 laptop.
2014 depends on CPU_SUP_AMD && PCI
2016 source "drivers/pcmcia/Kconfig"
2018 source "drivers/pci/hotplug/Kconfig"
2021 bool "RapidIO support"
2025 If you say Y here, the kernel will include drivers and
2026 infrastructure code to support RapidIO interconnect devices.
2028 source "drivers/rapidio/Kconfig"
2033 menu "Executable file formats / Emulations"
2035 source "fs/Kconfig.binfmt"
2037 config IA32_EMULATION
2038 bool "IA32 Emulation"
2040 select COMPAT_BINFMT_ELF
2042 Include code to run 32-bit programs under a 64-bit kernel. You should
2043 likely turn this on, unless you're 100% sure that you don't have any
2044 32-bit programs left.
2047 tristate "IA32 a.out support"
2048 depends on IA32_EMULATION
2050 Support old a.out binaries in the 32bit emulation.
2054 depends on IA32_EMULATION
2056 config COMPAT_FOR_U64_ALIGNMENT
2060 config SYSVIPC_COMPAT
2062 depends on COMPAT && SYSVIPC
2066 depends on COMPAT && KEYS
2072 config HAVE_ATOMIC_IOMAP
2076 config HAVE_TEXT_POKE_SMP
2078 select STOP_MACHINE if SMP
2080 source "net/Kconfig"
2082 source "drivers/Kconfig"
2084 source "drivers/firmware/Kconfig"
2088 source "arch/x86/Kconfig.debug"
2090 source "security/Kconfig"
2092 source "crypto/Kconfig"
2094 source "arch/x86/kvm/Kconfig"
2096 source "lib/Kconfig"