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
627 APB timer is the replacement for 8254, HPET on X86 MID platforms.
628 The APBT provides a stable time base on SMP
629 systems, unlike the TSC, but it is more expensive to access,
630 as it is off-chip. APB timers are always running regardless of CPU
631 C states, they are used as per CPU clockevent device when possible.
633 # Mark as expert because too many people got it wrong.
634 # The code disables itself when not needed.
637 bool "Enable DMI scanning" if EXPERT
639 Enabled scanning of DMI to identify machine quirks. Say Y
640 here unless you have verified that your setup is not
641 affected by entries in the DMI blacklist. Required by PNP
645 bool "GART IOMMU support" if EXPERT
648 depends on X86_64 && PCI && AMD_NB
650 Support for full DMA access of devices with 32bit memory access only
651 on systems with more than 3GB. This is usually needed for USB,
652 sound, many IDE/SATA chipsets and some other devices.
653 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
654 based hardware IOMMU and a software bounce buffer based IOMMU used
655 on Intel systems and as fallback.
656 The code is only active when needed (enough memory and limited
657 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
661 bool "IBM Calgary IOMMU support"
663 depends on X86_64 && PCI && EXPERIMENTAL
665 Support for hardware IOMMUs in IBM's xSeries x366 and x460
666 systems. Needed to run systems with more than 3GB of memory
667 properly with 32-bit PCI devices that do not support DAC
668 (Double Address Cycle). Calgary also supports bus level
669 isolation, where all DMAs pass through the IOMMU. This
670 prevents them from going anywhere except their intended
671 destination. This catches hard-to-find kernel bugs and
672 mis-behaving drivers and devices that do not use the DMA-API
673 properly to set up their DMA buffers. The IOMMU can be
674 turned off at boot time with the iommu=off parameter.
675 Normally the kernel will make the right choice by itself.
678 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
680 prompt "Should Calgary be enabled by default?"
681 depends on CALGARY_IOMMU
683 Should Calgary be enabled by default? if you choose 'y', Calgary
684 will be used (if it exists). If you choose 'n', Calgary will not be
685 used even if it exists. If you choose 'n' and would like to use
686 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
689 # need this always selected by IOMMU for the VIA workaround
693 Support for software bounce buffers used on x86-64 systems
694 which don't have a hardware IOMMU (e.g. the current generation
695 of Intel's x86-64 CPUs). Using this PCI devices which can only
696 access 32-bits of memory can be used on systems with more than
697 3 GB of memory. If unsure, say Y.
700 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
703 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
704 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
705 select CPUMASK_OFFSTACK
707 Enable maximum number of CPUS and NUMA Nodes for this architecture.
711 int "Maximum number of CPUs" if SMP && !MAXSMP
712 range 2 8 if SMP && X86_32 && !X86_BIGSMP
713 range 2 512 if SMP && !MAXSMP
715 default "4096" if MAXSMP
716 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
719 This allows you to specify the maximum number of CPUs which this
720 kernel will support. The maximum supported value is 512 and the
721 minimum value which makes sense is 2.
723 This is purely to save memory - each supported CPU adds
724 approximately eight kilobytes to the kernel image.
727 bool "SMT (Hyperthreading) scheduler support"
730 SMT scheduler support improves the CPU scheduler's decision making
731 when dealing with Intel Pentium 4 chips with HyperThreading at a
732 cost of slightly increased overhead in some places. If unsure say
737 prompt "Multi-core scheduler support"
740 Multi-core scheduler support improves the CPU scheduler's decision
741 making when dealing with multi-core CPU chips at a cost of slightly
742 increased overhead in some places. If unsure say N here.
744 config IRQ_TIME_ACCOUNTING
745 bool "Fine granularity task level IRQ time accounting"
748 Select this option to enable fine granularity task irq time
749 accounting. This is done by reading a timestamp on each
750 transitions between softirq and hardirq state, so there can be a
751 small performance impact.
753 If in doubt, say N here.
755 source "kernel/Kconfig.preempt"
758 bool "Local APIC support on uniprocessors"
759 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
761 A local APIC (Advanced Programmable Interrupt Controller) is an
762 integrated interrupt controller in the CPU. If you have a single-CPU
763 system which has a processor with a local APIC, you can say Y here to
764 enable and use it. If you say Y here even though your machine doesn't
765 have a local APIC, then the kernel will still run with no slowdown at
766 all. The local APIC supports CPU-generated self-interrupts (timer,
767 performance counters), and the NMI watchdog which detects hard
771 bool "IO-APIC support on uniprocessors"
772 depends on X86_UP_APIC
774 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
775 SMP-capable replacement for PC-style interrupt controllers. Most
776 SMP systems and many recent uniprocessor systems have one.
778 If you have a single-CPU system with an IO-APIC, you can say Y here
779 to use it. If you say Y here even though your machine doesn't have
780 an IO-APIC, then the kernel will still run with no slowdown at all.
782 config X86_LOCAL_APIC
784 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
788 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
790 config X86_VISWS_APIC
792 depends on X86_32 && X86_VISWS
794 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
795 bool "Reroute for broken boot IRQs"
796 depends on X86_IO_APIC
798 This option enables a workaround that fixes a source of
799 spurious interrupts. This is recommended when threaded
800 interrupt handling is used on systems where the generation of
801 superfluous "boot interrupts" cannot be disabled.
803 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
804 entry in the chipset's IO-APIC is masked (as, e.g. the RT
805 kernel does during interrupt handling). On chipsets where this
806 boot IRQ generation cannot be disabled, this workaround keeps
807 the original IRQ line masked so that only the equivalent "boot
808 IRQ" is delivered to the CPUs. The workaround also tells the
809 kernel to set up the IRQ handler on the boot IRQ line. In this
810 way only one interrupt is delivered to the kernel. Otherwise
811 the spurious second interrupt may cause the kernel to bring
812 down (vital) interrupt lines.
814 Only affects "broken" chipsets. Interrupt sharing may be
815 increased on these systems.
818 bool "Machine Check / overheating reporting"
820 Machine Check support allows the processor to notify the
821 kernel if it detects a problem (e.g. overheating, data corruption).
822 The action the kernel takes depends on the severity of the problem,
823 ranging from warning messages to halting the machine.
827 prompt "Intel MCE features"
828 depends on X86_MCE && X86_LOCAL_APIC
830 Additional support for intel specific MCE features such as
835 prompt "AMD MCE features"
836 depends on X86_MCE && X86_LOCAL_APIC
838 Additional support for AMD specific MCE features such as
839 the DRAM Error Threshold.
841 config X86_ANCIENT_MCE
842 bool "Support for old Pentium 5 / WinChip machine checks"
843 depends on X86_32 && X86_MCE
845 Include support for machine check handling on old Pentium 5 or WinChip
846 systems. These typically need to be enabled explicitely on the command
849 config X86_MCE_THRESHOLD
850 depends on X86_MCE_AMD || X86_MCE_INTEL
853 config X86_MCE_INJECT
855 tristate "Machine check injector support"
857 Provide support for injecting machine checks for testing purposes.
858 If you don't know what a machine check is and you don't do kernel
859 QA it is safe to say n.
861 config X86_THERMAL_VECTOR
863 depends on X86_MCE_INTEL
866 bool "Enable VM86 support" if EXPERT
870 This option is required by programs like DOSEMU to run 16-bit legacy
871 code on X86 processors. It also may be needed by software like
872 XFree86 to initialize some video cards via BIOS. Disabling this
873 option saves about 6k.
876 tristate "Toshiba Laptop support"
879 This adds a driver to safely access the System Management Mode of
880 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
881 not work on models with a Phoenix BIOS. The System Management Mode
882 is used to set the BIOS and power saving options on Toshiba portables.
884 For information on utilities to make use of this driver see the
885 Toshiba Linux utilities web site at:
886 <http://www.buzzard.org.uk/toshiba/>.
888 Say Y if you intend to run this kernel on a Toshiba portable.
892 tristate "Dell laptop support"
895 This adds a driver to safely access the System Management Mode
896 of the CPU on the Dell Inspiron 8000. The System Management Mode
897 is used to read cpu temperature and cooling fan status and to
898 control the fans on the I8K portables.
900 This driver has been tested only on the Inspiron 8000 but it may
901 also work with other Dell laptops. You can force loading on other
902 models by passing the parameter `force=1' to the module. Use at
905 For information on utilities to make use of this driver see the
906 I8K Linux utilities web site at:
907 <http://people.debian.org/~dz/i8k/>
909 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
912 config X86_REBOOTFIXUPS
913 bool "Enable X86 board specific fixups for reboot"
916 This enables chipset and/or board specific fixups to be done
917 in order to get reboot to work correctly. This is only needed on
918 some combinations of hardware and BIOS. The symptom, for which
919 this config is intended, is when reboot ends with a stalled/hung
922 Currently, the only fixup is for the Geode machines using
923 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
925 Say Y if you want to enable the fixup. Currently, it's safe to
926 enable this option even if you don't need it.
930 tristate "/dev/cpu/microcode - microcode support"
933 If you say Y here, you will be able to update the microcode on
934 certain Intel and AMD processors. The Intel support is for the
935 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
936 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
937 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
938 You will obviously need the actual microcode binary data itself
939 which is not shipped with the Linux kernel.
941 This option selects the general module only, you need to select
942 at least one vendor specific module as well.
944 To compile this driver as a module, choose M here: the
945 module will be called microcode.
947 config MICROCODE_INTEL
948 bool "Intel microcode patch loading support"
953 This options enables microcode patch loading support for Intel
956 For latest news and information on obtaining all the required
957 Intel ingredients for this driver, check:
958 <http://www.urbanmyth.org/microcode/>.
961 bool "AMD microcode patch loading support"
965 If you select this option, microcode patch loading support for AMD
966 processors will be enabled.
968 config MICROCODE_OLD_INTERFACE
973 tristate "/dev/cpu/*/msr - Model-specific register support"
975 This device gives privileged processes access to the x86
976 Model-Specific Registers (MSRs). It is a character device with
977 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
978 MSR accesses are directed to a specific CPU on multi-processor
982 tristate "/dev/cpu/*/cpuid - CPU information support"
984 This device gives processes access to the x86 CPUID instruction to
985 be executed on a specific processor. It is a character device
986 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
990 prompt "High Memory Support"
991 default HIGHMEM64G if X86_NUMAQ
997 depends on !X86_NUMAQ
999 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1000 However, the address space of 32-bit x86 processors is only 4
1001 Gigabytes large. That means that, if you have a large amount of
1002 physical memory, not all of it can be "permanently mapped" by the
1003 kernel. The physical memory that's not permanently mapped is called
1006 If you are compiling a kernel which will never run on a machine with
1007 more than 1 Gigabyte total physical RAM, answer "off" here (default
1008 choice and suitable for most users). This will result in a "3GB/1GB"
1009 split: 3GB are mapped so that each process sees a 3GB virtual memory
1010 space and the remaining part of the 4GB virtual memory space is used
1011 by the kernel to permanently map as much physical memory as
1014 If the machine has between 1 and 4 Gigabytes physical RAM, then
1017 If more than 4 Gigabytes is used then answer "64GB" here. This
1018 selection turns Intel PAE (Physical Address Extension) mode on.
1019 PAE implements 3-level paging on IA32 processors. PAE is fully
1020 supported by Linux, PAE mode is implemented on all recent Intel
1021 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1022 then the kernel will not boot on CPUs that don't support PAE!
1024 The actual amount of total physical memory will either be
1025 auto detected or can be forced by using a kernel command line option
1026 such as "mem=256M". (Try "man bootparam" or see the documentation of
1027 your boot loader (lilo or loadlin) about how to pass options to the
1028 kernel at boot time.)
1030 If unsure, say "off".
1034 depends on !X86_NUMAQ
1036 Select this if you have a 32-bit processor and between 1 and 4
1037 gigabytes of physical RAM.
1041 depends on !M386 && !M486
1044 Select this if you have a 32-bit processor and more than 4
1045 gigabytes of physical RAM.
1050 depends on EXPERIMENTAL
1051 prompt "Memory split" if EXPERT
1055 Select the desired split between kernel and user memory.
1057 If the address range available to the kernel is less than the
1058 physical memory installed, the remaining memory will be available
1059 as "high memory". Accessing high memory is a little more costly
1060 than low memory, as it needs to be mapped into the kernel first.
1061 Note that increasing the kernel address space limits the range
1062 available to user programs, making the address space there
1063 tighter. Selecting anything other than the default 3G/1G split
1064 will also likely make your kernel incompatible with binary-only
1067 If you are not absolutely sure what you are doing, leave this
1071 bool "3G/1G user/kernel split"
1072 config VMSPLIT_3G_OPT
1074 bool "3G/1G user/kernel split (for full 1G low memory)"
1076 bool "2G/2G user/kernel split"
1077 config VMSPLIT_2G_OPT
1079 bool "2G/2G user/kernel split (for full 2G low memory)"
1081 bool "1G/3G user/kernel split"
1086 default 0xB0000000 if VMSPLIT_3G_OPT
1087 default 0x80000000 if VMSPLIT_2G
1088 default 0x78000000 if VMSPLIT_2G_OPT
1089 default 0x40000000 if VMSPLIT_1G
1095 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1098 bool "PAE (Physical Address Extension) Support"
1099 depends on X86_32 && !HIGHMEM4G
1101 PAE is required for NX support, and furthermore enables
1102 larger swapspace support for non-overcommit purposes. It
1103 has the cost of more pagetable lookup overhead, and also
1104 consumes more pagetable space per process.
1106 config ARCH_PHYS_ADDR_T_64BIT
1107 def_bool X86_64 || X86_PAE
1109 config ARCH_DMA_ADDR_T_64BIT
1110 def_bool X86_64 || HIGHMEM64G
1112 config DIRECT_GBPAGES
1113 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1117 Allow the kernel linear mapping to use 1GB pages on CPUs that
1118 support it. This can improve the kernel's performance a tiny bit by
1119 reducing TLB pressure. If in doubt, say "Y".
1121 # Common NUMA Features
1123 bool "Numa Memory Allocation and Scheduler Support"
1125 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1126 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1128 Enable NUMA (Non Uniform Memory Access) support.
1130 The kernel will try to allocate memory used by a CPU on the
1131 local memory controller of the CPU and add some more
1132 NUMA awareness to the kernel.
1134 For 64-bit this is recommended if the system is Intel Core i7
1135 (or later), AMD Opteron, or EM64T NUMA.
1137 For 32-bit this is only needed on (rare) 32-bit-only platforms
1138 that support NUMA topologies, such as NUMAQ / Summit, or if you
1139 boot a 32-bit kernel on a 64-bit NUMA platform.
1141 Otherwise, you should say N.
1143 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1144 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1148 prompt "Old style AMD Opteron NUMA detection"
1149 depends on X86_64 && NUMA && PCI
1151 Enable AMD NUMA node topology detection. You should say Y here if
1152 you have a multi processor AMD system. This uses an old method to
1153 read the NUMA configuration directly from the builtin Northbridge
1154 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1155 which also takes priority if both are compiled in.
1157 config X86_64_ACPI_NUMA
1159 prompt "ACPI NUMA detection"
1160 depends on X86_64 && NUMA && ACPI && PCI
1163 Enable ACPI SRAT based node topology detection.
1165 # Some NUMA nodes have memory ranges that span
1166 # other nodes. Even though a pfn is valid and
1167 # between a node's start and end pfns, it may not
1168 # reside on that node. See memmap_init_zone()
1170 config NODES_SPAN_OTHER_NODES
1172 depends on X86_64_ACPI_NUMA
1175 bool "NUMA emulation"
1178 Enable NUMA emulation. A flat machine will be split
1179 into virtual nodes when booted with "numa=fake=N", where N is the
1180 number of nodes. This is only useful for debugging.
1183 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1185 default "10" if MAXSMP
1186 default "6" if X86_64
1187 default "4" if X86_NUMAQ
1189 depends on NEED_MULTIPLE_NODES
1191 Specify the maximum number of NUMA Nodes available on the target
1192 system. Increases memory reserved to accommodate various tables.
1194 config HAVE_ARCH_BOOTMEM
1196 depends on X86_32 && NUMA
1198 config HAVE_ARCH_ALLOC_REMAP
1200 depends on X86_32 && NUMA
1202 config ARCH_HAVE_MEMORY_PRESENT
1204 depends on X86_32 && DISCONTIGMEM
1206 config NEED_NODE_MEMMAP_SIZE
1208 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1210 config ARCH_FLATMEM_ENABLE
1212 depends on X86_32 && !NUMA
1214 config ARCH_DISCONTIGMEM_ENABLE
1216 depends on NUMA && X86_32
1218 config ARCH_DISCONTIGMEM_DEFAULT
1220 depends on NUMA && X86_32
1222 config ARCH_SPARSEMEM_ENABLE
1224 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1225 select SPARSEMEM_STATIC if X86_32
1226 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1228 config ARCH_SPARSEMEM_DEFAULT
1232 config ARCH_SELECT_MEMORY_MODEL
1234 depends on ARCH_SPARSEMEM_ENABLE
1236 config ARCH_MEMORY_PROBE
1238 depends on MEMORY_HOTPLUG
1240 config ARCH_PROC_KCORE_TEXT
1242 depends on X86_64 && PROC_KCORE
1244 config ILLEGAL_POINTER_VALUE
1247 default 0xdead000000000000 if X86_64
1252 bool "Allocate 3rd-level pagetables from highmem"
1255 The VM uses one page table entry for each page of physical memory.
1256 For systems with a lot of RAM, this can be wasteful of precious
1257 low memory. Setting this option will put user-space page table
1258 entries in high memory.
1260 config X86_CHECK_BIOS_CORRUPTION
1261 bool "Check for low memory corruption"
1263 Periodically check for memory corruption in low memory, which
1264 is suspected to be caused by BIOS. Even when enabled in the
1265 configuration, it is disabled at runtime. Enable it by
1266 setting "memory_corruption_check=1" on the kernel command
1267 line. By default it scans the low 64k of memory every 60
1268 seconds; see the memory_corruption_check_size and
1269 memory_corruption_check_period parameters in
1270 Documentation/kernel-parameters.txt to adjust this.
1272 When enabled with the default parameters, this option has
1273 almost no overhead, as it reserves a relatively small amount
1274 of memory and scans it infrequently. It both detects corruption
1275 and prevents it from affecting the running system.
1277 It is, however, intended as a diagnostic tool; if repeatable
1278 BIOS-originated corruption always affects the same memory,
1279 you can use memmap= to prevent the kernel from using that
1282 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1283 bool "Set the default setting of memory_corruption_check"
1284 depends on X86_CHECK_BIOS_CORRUPTION
1287 Set whether the default state of memory_corruption_check is
1290 config X86_RESERVE_LOW
1291 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1295 Specify the amount of low memory to reserve for the BIOS.
1297 The first page contains BIOS data structures that the kernel
1298 must not use, so that page must always be reserved.
1300 By default we reserve the first 64K of physical RAM, as a
1301 number of BIOSes are known to corrupt that memory range
1302 during events such as suspend/resume or monitor cable
1303 insertion, so it must not be used by the kernel.
1305 You can set this to 4 if you are absolutely sure that you
1306 trust the BIOS to get all its memory reservations and usages
1307 right. If you know your BIOS have problems beyond the
1308 default 64K area, you can set this to 640 to avoid using the
1309 entire low memory range.
1311 If you have doubts about the BIOS (e.g. suspend/resume does
1312 not work or there's kernel crashes after certain hardware
1313 hotplug events) then you might want to enable
1314 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1315 typical corruption patterns.
1317 Leave this to the default value of 64 if you are unsure.
1319 config MATH_EMULATION
1321 prompt "Math emulation" if X86_32
1323 Linux can emulate a math coprocessor (used for floating point
1324 operations) if you don't have one. 486DX and Pentium processors have
1325 a math coprocessor built in, 486SX and 386 do not, unless you added
1326 a 487DX or 387, respectively. (The messages during boot time can
1327 give you some hints here ["man dmesg"].) Everyone needs either a
1328 coprocessor or this emulation.
1330 If you don't have a math coprocessor, you need to say Y here; if you
1331 say Y here even though you have a coprocessor, the coprocessor will
1332 be used nevertheless. (This behavior can be changed with the kernel
1333 command line option "no387", which comes handy if your coprocessor
1334 is broken. Try "man bootparam" or see the documentation of your boot
1335 loader (lilo or loadlin) about how to pass options to the kernel at
1336 boot time.) This means that it is a good idea to say Y here if you
1337 intend to use this kernel on different machines.
1339 More information about the internals of the Linux math coprocessor
1340 emulation can be found in <file:arch/x86/math-emu/README>.
1342 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1343 kernel, it won't hurt.
1347 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1349 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1350 the Memory Type Range Registers (MTRRs) may be used to control
1351 processor access to memory ranges. This is most useful if you have
1352 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1353 allows bus write transfers to be combined into a larger transfer
1354 before bursting over the PCI/AGP bus. This can increase performance
1355 of image write operations 2.5 times or more. Saying Y here creates a
1356 /proc/mtrr file which may be used to manipulate your processor's
1357 MTRRs. Typically the X server should use this.
1359 This code has a reasonably generic interface so that similar
1360 control registers on other processors can be easily supported
1363 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1364 Registers (ARRs) which provide a similar functionality to MTRRs. For
1365 these, the ARRs are used to emulate the MTRRs.
1366 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1367 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1368 write-combining. All of these processors are supported by this code
1369 and it makes sense to say Y here if you have one of them.
1371 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1372 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1373 can lead to all sorts of problems, so it's good to say Y here.
1375 You can safely say Y even if your machine doesn't have MTRRs, you'll
1376 just add about 9 KB to your kernel.
1378 See <file:Documentation/x86/mtrr.txt> for more information.
1380 config MTRR_SANITIZER
1382 prompt "MTRR cleanup support"
1385 Convert MTRR layout from continuous to discrete, so X drivers can
1386 add writeback entries.
1388 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1389 The largest mtrr entry size for a continuous block can be set with
1394 config MTRR_SANITIZER_ENABLE_DEFAULT
1395 int "MTRR cleanup enable value (0-1)"
1398 depends on MTRR_SANITIZER
1400 Enable mtrr cleanup default value
1402 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1403 int "MTRR cleanup spare reg num (0-7)"
1406 depends on MTRR_SANITIZER
1408 mtrr cleanup spare entries default, it can be changed via
1409 mtrr_spare_reg_nr=N on the kernel command line.
1413 prompt "x86 PAT support" if EXPERT
1416 Use PAT attributes to setup page level cache control.
1418 PATs are the modern equivalents of MTRRs and are much more
1419 flexible than MTRRs.
1421 Say N here if you see bootup problems (boot crash, boot hang,
1422 spontaneous reboots) or a non-working video driver.
1426 config ARCH_USES_PG_UNCACHED
1431 bool "EFI runtime service support"
1434 This enables the kernel to use EFI runtime services that are
1435 available (such as the EFI variable services).
1437 This option is only useful on systems that have EFI firmware.
1438 In addition, you should use the latest ELILO loader available
1439 at <http://elilo.sourceforge.net> in order to take advantage
1440 of EFI runtime services. However, even with this option, the
1441 resultant kernel should continue to boot on existing non-EFI
1446 prompt "Enable seccomp to safely compute untrusted bytecode"
1448 This kernel feature is useful for number crunching applications
1449 that may need to compute untrusted bytecode during their
1450 execution. By using pipes or other transports made available to
1451 the process as file descriptors supporting the read/write
1452 syscalls, it's possible to isolate those applications in
1453 their own address space using seccomp. Once seccomp is
1454 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1455 and the task is only allowed to execute a few safe syscalls
1456 defined by each seccomp mode.
1458 If unsure, say Y. Only embedded should say N here.
1460 config CC_STACKPROTECTOR
1461 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1463 This option turns on the -fstack-protector GCC feature. This
1464 feature puts, at the beginning of functions, a canary value on
1465 the stack just before the return address, and validates
1466 the value just before actually returning. Stack based buffer
1467 overflows (that need to overwrite this return address) now also
1468 overwrite the canary, which gets detected and the attack is then
1469 neutralized via a kernel panic.
1471 This feature requires gcc version 4.2 or above, or a distribution
1472 gcc with the feature backported. Older versions are automatically
1473 detected and for those versions, this configuration option is
1474 ignored. (and a warning is printed during bootup)
1476 source kernel/Kconfig.hz
1479 bool "kexec system call"
1481 kexec is a system call that implements the ability to shutdown your
1482 current kernel, and to start another kernel. It is like a reboot
1483 but it is independent of the system firmware. And like a reboot
1484 you can start any kernel with it, not just Linux.
1486 The name comes from the similarity to the exec system call.
1488 It is an ongoing process to be certain the hardware in a machine
1489 is properly shutdown, so do not be surprised if this code does not
1490 initially work for you. It may help to enable device hotplugging
1491 support. As of this writing the exact hardware interface is
1492 strongly in flux, so no good recommendation can be made.
1495 bool "kernel crash dumps"
1496 depends on X86_64 || (X86_32 && HIGHMEM)
1498 Generate crash dump after being started by kexec.
1499 This should be normally only set in special crash dump kernels
1500 which are loaded in the main kernel with kexec-tools into
1501 a specially reserved region and then later executed after
1502 a crash by kdump/kexec. The crash dump kernel must be compiled
1503 to a memory address not used by the main kernel or BIOS using
1504 PHYSICAL_START, or it must be built as a relocatable image
1505 (CONFIG_RELOCATABLE=y).
1506 For more details see Documentation/kdump/kdump.txt
1509 bool "kexec jump (EXPERIMENTAL)"
1510 depends on EXPERIMENTAL
1511 depends on KEXEC && HIBERNATION
1513 Jump between original kernel and kexeced kernel and invoke
1514 code in physical address mode via KEXEC
1516 config PHYSICAL_START
1517 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1520 This gives the physical address where the kernel is loaded.
1522 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1523 bzImage will decompress itself to above physical address and
1524 run from there. Otherwise, bzImage will run from the address where
1525 it has been loaded by the boot loader and will ignore above physical
1528 In normal kdump cases one does not have to set/change this option
1529 as now bzImage can be compiled as a completely relocatable image
1530 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1531 address. This option is mainly useful for the folks who don't want
1532 to use a bzImage for capturing the crash dump and want to use a
1533 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1534 to be specifically compiled to run from a specific memory area
1535 (normally a reserved region) and this option comes handy.
1537 So if you are using bzImage for capturing the crash dump,
1538 leave the value here unchanged to 0x1000000 and set
1539 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1540 for capturing the crash dump change this value to start of
1541 the reserved region. In other words, it can be set based on
1542 the "X" value as specified in the "crashkernel=YM@XM"
1543 command line boot parameter passed to the panic-ed
1544 kernel. Please take a look at Documentation/kdump/kdump.txt
1545 for more details about crash dumps.
1547 Usage of bzImage for capturing the crash dump is recommended as
1548 one does not have to build two kernels. Same kernel can be used
1549 as production kernel and capture kernel. Above option should have
1550 gone away after relocatable bzImage support is introduced. But it
1551 is present because there are users out there who continue to use
1552 vmlinux for dump capture. This option should go away down the
1555 Don't change this unless you know what you are doing.
1558 bool "Build a relocatable kernel"
1561 This builds a kernel image that retains relocation information
1562 so it can be loaded someplace besides the default 1MB.
1563 The relocations tend to make the kernel binary about 10% larger,
1564 but are discarded at runtime.
1566 One use is for the kexec on panic case where the recovery kernel
1567 must live at a different physical address than the primary
1570 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1571 it has been loaded at and the compile time physical address
1572 (CONFIG_PHYSICAL_START) is ignored.
1574 # Relocation on x86-32 needs some additional build support
1575 config X86_NEED_RELOCS
1577 depends on X86_32 && RELOCATABLE
1579 config PHYSICAL_ALIGN
1580 hex "Alignment value to which kernel should be aligned" if X86_32
1582 range 0x2000 0x1000000
1584 This value puts the alignment restrictions on physical address
1585 where kernel is loaded and run from. Kernel is compiled for an
1586 address which meets above alignment restriction.
1588 If bootloader loads the kernel at a non-aligned address and
1589 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1590 address aligned to above value and run from there.
1592 If bootloader loads the kernel at a non-aligned address and
1593 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1594 load address and decompress itself to the address it has been
1595 compiled for and run from there. The address for which kernel is
1596 compiled already meets above alignment restrictions. Hence the
1597 end result is that kernel runs from a physical address meeting
1598 above alignment restrictions.
1600 Don't change this unless you know what you are doing.
1603 bool "Support for hot-pluggable CPUs"
1604 depends on SMP && HOTPLUG
1606 Say Y here to allow turning CPUs off and on. CPUs can be
1607 controlled through /sys/devices/system/cpu.
1608 ( Note: power management support will enable this option
1609 automatically on SMP systems. )
1610 Say N if you want to disable CPU hotplug.
1614 prompt "Compat VDSO support"
1615 depends on X86_32 || IA32_EMULATION
1617 Map the 32-bit VDSO to the predictable old-style address too.
1619 Say N here if you are running a sufficiently recent glibc
1620 version (2.3.3 or later), to remove the high-mapped
1621 VDSO mapping and to exclusively use the randomized VDSO.
1626 bool "Built-in kernel command line"
1628 Allow for specifying boot arguments to the kernel at
1629 build time. On some systems (e.g. embedded ones), it is
1630 necessary or convenient to provide some or all of the
1631 kernel boot arguments with the kernel itself (that is,
1632 to not rely on the boot loader to provide them.)
1634 To compile command line arguments into the kernel,
1635 set this option to 'Y', then fill in the
1636 the boot arguments in CONFIG_CMDLINE.
1638 Systems with fully functional boot loaders (i.e. non-embedded)
1639 should leave this option set to 'N'.
1642 string "Built-in kernel command string"
1643 depends on CMDLINE_BOOL
1646 Enter arguments here that should be compiled into the kernel
1647 image and used at boot time. If the boot loader provides a
1648 command line at boot time, it is appended to this string to
1649 form the full kernel command line, when the system boots.
1651 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1652 change this behavior.
1654 In most cases, the command line (whether built-in or provided
1655 by the boot loader) should specify the device for the root
1658 config CMDLINE_OVERRIDE
1659 bool "Built-in command line overrides boot loader arguments"
1660 depends on CMDLINE_BOOL
1662 Set this option to 'Y' to have the kernel ignore the boot loader
1663 command line, and use ONLY the built-in command line.
1665 This is used to work around broken boot loaders. This should
1666 be set to 'N' under normal conditions.
1670 config ARCH_ENABLE_MEMORY_HOTPLUG
1672 depends on X86_64 || (X86_32 && HIGHMEM)
1674 config ARCH_ENABLE_MEMORY_HOTREMOVE
1676 depends on MEMORY_HOTPLUG
1678 config USE_PERCPU_NUMA_NODE_ID
1682 menu "Power management and ACPI options"
1684 config ARCH_HIBERNATION_HEADER
1686 depends on X86_64 && HIBERNATION
1688 source "kernel/power/Kconfig"
1690 source "drivers/acpi/Kconfig"
1692 source "drivers/sfi/Kconfig"
1696 depends on APM || APM_MODULE
1699 tristate "APM (Advanced Power Management) BIOS support"
1700 depends on X86_32 && PM_SLEEP
1702 APM is a BIOS specification for saving power using several different
1703 techniques. This is mostly useful for battery powered laptops with
1704 APM compliant BIOSes. If you say Y here, the system time will be
1705 reset after a RESUME operation, the /proc/apm device will provide
1706 battery status information, and user-space programs will receive
1707 notification of APM "events" (e.g. battery status change).
1709 If you select "Y" here, you can disable actual use of the APM
1710 BIOS by passing the "apm=off" option to the kernel at boot time.
1712 Note that the APM support is almost completely disabled for
1713 machines with more than one CPU.
1715 In order to use APM, you will need supporting software. For location
1716 and more information, read <file:Documentation/power/pm.txt> and the
1717 Battery Powered Linux mini-HOWTO, available from
1718 <http://www.tldp.org/docs.html#howto>.
1720 This driver does not spin down disk drives (see the hdparm(8)
1721 manpage ("man 8 hdparm") for that), and it doesn't turn off
1722 VESA-compliant "green" monitors.
1724 This driver does not support the TI 4000M TravelMate and the ACER
1725 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1726 desktop machines also don't have compliant BIOSes, and this driver
1727 may cause those machines to panic during the boot phase.
1729 Generally, if you don't have a battery in your machine, there isn't
1730 much point in using this driver and you should say N. If you get
1731 random kernel OOPSes or reboots that don't seem to be related to
1732 anything, try disabling/enabling this option (or disabling/enabling
1735 Some other things you should try when experiencing seemingly random,
1738 1) make sure that you have enough swap space and that it is
1740 2) pass the "no-hlt" option to the kernel
1741 3) switch on floating point emulation in the kernel and pass
1742 the "no387" option to the kernel
1743 4) pass the "floppy=nodma" option to the kernel
1744 5) pass the "mem=4M" option to the kernel (thereby disabling
1745 all but the first 4 MB of RAM)
1746 6) make sure that the CPU is not over clocked.
1747 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1748 8) disable the cache from your BIOS settings
1749 9) install a fan for the video card or exchange video RAM
1750 10) install a better fan for the CPU
1751 11) exchange RAM chips
1752 12) exchange the motherboard.
1754 To compile this driver as a module, choose M here: the
1755 module will be called apm.
1759 config APM_IGNORE_USER_SUSPEND
1760 bool "Ignore USER SUSPEND"
1762 This option will ignore USER SUSPEND requests. On machines with a
1763 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1764 series notebooks, it is necessary to say Y because of a BIOS bug.
1766 config APM_DO_ENABLE
1767 bool "Enable PM at boot time"
1769 Enable APM features at boot time. From page 36 of the APM BIOS
1770 specification: "When disabled, the APM BIOS does not automatically
1771 power manage devices, enter the Standby State, enter the Suspend
1772 State, or take power saving steps in response to CPU Idle calls."
1773 This driver will make CPU Idle calls when Linux is idle (unless this
1774 feature is turned off -- see "Do CPU IDLE calls", below). This
1775 should always save battery power, but more complicated APM features
1776 will be dependent on your BIOS implementation. You may need to turn
1777 this option off if your computer hangs at boot time when using APM
1778 support, or if it beeps continuously instead of suspending. Turn
1779 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1780 T400CDT. This is off by default since most machines do fine without
1784 bool "Make CPU Idle calls when idle"
1786 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1787 On some machines, this can activate improved power savings, such as
1788 a slowed CPU clock rate, when the machine is idle. These idle calls
1789 are made after the idle loop has run for some length of time (e.g.,
1790 333 mS). On some machines, this will cause a hang at boot time or
1791 whenever the CPU becomes idle. (On machines with more than one CPU,
1792 this option does nothing.)
1794 config APM_DISPLAY_BLANK
1795 bool "Enable console blanking using APM"
1797 Enable console blanking using the APM. Some laptops can use this to
1798 turn off the LCD backlight when the screen blanker of the Linux
1799 virtual console blanks the screen. Note that this is only used by
1800 the virtual console screen blanker, and won't turn off the backlight
1801 when using the X Window system. This also doesn't have anything to
1802 do with your VESA-compliant power-saving monitor. Further, this
1803 option doesn't work for all laptops -- it might not turn off your
1804 backlight at all, or it might print a lot of errors to the console,
1805 especially if you are using gpm.
1807 config APM_ALLOW_INTS
1808 bool "Allow interrupts during APM BIOS calls"
1810 Normally we disable external interrupts while we are making calls to
1811 the APM BIOS as a measure to lessen the effects of a badly behaving
1812 BIOS implementation. The BIOS should reenable interrupts if it
1813 needs to. Unfortunately, some BIOSes do not -- especially those in
1814 many of the newer IBM Thinkpads. If you experience hangs when you
1815 suspend, try setting this to Y. Otherwise, say N.
1819 source "drivers/cpufreq/Kconfig"
1821 source "drivers/cpuidle/Kconfig"
1823 source "drivers/idle/Kconfig"
1828 menu "Bus options (PCI etc.)"
1833 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1835 Find out whether you have a PCI motherboard. PCI is the name of a
1836 bus system, i.e. the way the CPU talks to the other stuff inside
1837 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1838 VESA. If you have PCI, say Y, otherwise N.
1841 prompt "PCI access mode"
1842 depends on X86_32 && PCI
1845 On PCI systems, the BIOS can be used to detect the PCI devices and
1846 determine their configuration. However, some old PCI motherboards
1847 have BIOS bugs and may crash if this is done. Also, some embedded
1848 PCI-based systems don't have any BIOS at all. Linux can also try to
1849 detect the PCI hardware directly without using the BIOS.
1851 With this option, you can specify how Linux should detect the
1852 PCI devices. If you choose "BIOS", the BIOS will be used,
1853 if you choose "Direct", the BIOS won't be used, and if you
1854 choose "MMConfig", then PCI Express MMCONFIG will be used.
1855 If you choose "Any", the kernel will try MMCONFIG, then the
1856 direct access method and falls back to the BIOS if that doesn't
1857 work. If unsure, go with the default, which is "Any".
1862 config PCI_GOMMCONFIG
1879 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1881 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1884 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1888 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1892 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1896 depends on PCI && XEN
1904 bool "Support mmconfig PCI config space access"
1905 depends on X86_64 && PCI && ACPI
1907 config PCI_CNB20LE_QUIRK
1908 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1910 depends on PCI && EXPERIMENTAL
1912 Read the PCI windows out of the CNB20LE host bridge. This allows
1913 PCI hotplug to work on systems with the CNB20LE chipset which do
1916 There's no public spec for this chipset, and this functionality
1917 is known to be incomplete.
1919 You should say N unless you know you need this.
1921 source "drivers/pci/pcie/Kconfig"
1923 source "drivers/pci/Kconfig"
1925 # x86_64 have no ISA slots, but can have ISA-style DMA.
1927 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1930 Enables ISA-style DMA support for devices requiring such controllers.
1938 Find out whether you have ISA slots on your motherboard. ISA is the
1939 name of a bus system, i.e. the way the CPU talks to the other stuff
1940 inside your box. Other bus systems are PCI, EISA, MicroChannel
1941 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1942 newer boards don't support it. If you have ISA, say Y, otherwise N.
1948 The Extended Industry Standard Architecture (EISA) bus was
1949 developed as an open alternative to the IBM MicroChannel bus.
1951 The EISA bus provided some of the features of the IBM MicroChannel
1952 bus while maintaining backward compatibility with cards made for
1953 the older ISA bus. The EISA bus saw limited use between 1988 and
1954 1995 when it was made obsolete by the PCI bus.
1956 Say Y here if you are building a kernel for an EISA-based machine.
1960 source "drivers/eisa/Kconfig"
1965 MicroChannel Architecture is found in some IBM PS/2 machines and
1966 laptops. It is a bus system similar to PCI or ISA. See
1967 <file:Documentation/mca.txt> (and especially the web page given
1968 there) before attempting to build an MCA bus kernel.
1970 source "drivers/mca/Kconfig"
1973 tristate "NatSemi SCx200 support"
1975 This provides basic support for National Semiconductor's
1976 (now AMD's) Geode processors. The driver probes for the
1977 PCI-IDs of several on-chip devices, so its a good dependency
1978 for other scx200_* drivers.
1980 If compiled as a module, the driver is named scx200.
1982 config SCx200HR_TIMER
1983 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1987 This driver provides a clocksource built upon the on-chip
1988 27MHz high-resolution timer. Its also a workaround for
1989 NSC Geode SC-1100's buggy TSC, which loses time when the
1990 processor goes idle (as is done by the scheduler). The
1991 other workaround is idle=poll boot option.
1994 bool "One Laptop Per Child support"
2000 Add support for detecting the unique features of the OLPC
2004 tristate "OLPC XO-1 support"
2005 depends on OLPC && MFD_CS5535
2007 Add support for non-essential features of the OLPC XO-1 laptop.
2013 depends on CPU_SUP_AMD && PCI
2015 source "drivers/pcmcia/Kconfig"
2017 source "drivers/pci/hotplug/Kconfig"
2020 bool "RapidIO support"
2024 If you say Y here, the kernel will include drivers and
2025 infrastructure code to support RapidIO interconnect devices.
2027 source "drivers/rapidio/Kconfig"
2032 menu "Executable file formats / Emulations"
2034 source "fs/Kconfig.binfmt"
2036 config IA32_EMULATION
2037 bool "IA32 Emulation"
2039 select COMPAT_BINFMT_ELF
2041 Include code to run 32-bit programs under a 64-bit kernel. You should
2042 likely turn this on, unless you're 100% sure that you don't have any
2043 32-bit programs left.
2046 tristate "IA32 a.out support"
2047 depends on IA32_EMULATION
2049 Support old a.out binaries in the 32bit emulation.
2053 depends on IA32_EMULATION
2055 config COMPAT_FOR_U64_ALIGNMENT
2059 config SYSVIPC_COMPAT
2061 depends on COMPAT && SYSVIPC
2065 depends on COMPAT && KEYS
2071 config HAVE_ATOMIC_IOMAP
2075 config HAVE_TEXT_POKE_SMP
2077 select STOP_MACHINE if SMP
2079 source "net/Kconfig"
2081 source "drivers/Kconfig"
2083 source "drivers/firmware/Kconfig"
2087 source "arch/x86/Kconfig.debug"
2089 source "security/Kconfig"
2091 source "crypto/Kconfig"
2093 source "arch/x86/kvm/Kconfig"
2095 source "lib/Kconfig"