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
18 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
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_FIND_NEXT_BIT
69 select GENERIC_IRQ_PROBE
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_IRQ_SHOW
72 select IRQ_FORCED_THREADING
73 select USE_GENERIC_SMP_HELPERS if SMP
74 select ARCH_NO_SYSDEV_OPS
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 GENERIC_CLOCKEVENTS_BROADCAST
100 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
102 config LOCKDEP_SUPPORT
105 config STACKTRACE_SUPPORT
108 config HAVE_LATENCYTOP_SUPPORT
115 bool "DMA memory allocation support" if EXPERT
118 DMA memory allocation support allows devices with less than 32-bit
119 addressing to allocate within the first 16MB of address space.
120 Disable if no such devices will be used.
127 config NEED_DMA_MAP_STATE
128 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
130 config NEED_SG_DMA_LENGTH
133 config GENERIC_ISA_DMA
142 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
144 config GENERIC_BUG_RELATIVE_POINTERS
147 config GENERIC_HWEIGHT
153 config ARCH_MAY_HAVE_PC_FDC
156 config RWSEM_GENERIC_SPINLOCK
159 config RWSEM_XCHGADD_ALGORITHM
162 config ARCH_HAS_CPU_IDLE_WAIT
165 config GENERIC_CALIBRATE_DELAY
168 config GENERIC_TIME_VSYSCALL
172 config ARCH_HAS_CPU_RELAX
175 config ARCH_HAS_DEFAULT_IDLE
178 config ARCH_HAS_CACHE_LINE_SIZE
181 config HAVE_SETUP_PER_CPU_AREA
184 config NEED_PER_CPU_EMBED_FIRST_CHUNK
187 config NEED_PER_CPU_PAGE_FIRST_CHUNK
190 config HAVE_CPUMASK_OF_CPU_MAP
193 config ARCH_HIBERNATION_POSSIBLE
196 config ARCH_SUSPEND_POSSIBLE
203 config ARCH_POPULATES_NODE_MAP
210 config ARCH_SUPPORTS_OPTIMIZED_INLINING
213 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
216 config HAVE_INTEL_TXT
218 depends on EXPERIMENTAL && DMAR && ACPI
222 depends on X86_32 && SMP
226 depends on X86_64 && SMP
232 config X86_32_LAZY_GS
234 depends on X86_32 && !CC_STACKPROTECTOR
236 config ARCH_HWEIGHT_CFLAGS
238 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
239 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
244 config ARCH_CPU_PROBE_RELEASE
246 depends on HOTPLUG_CPU
248 source "init/Kconfig"
249 source "kernel/Kconfig.freezer"
251 menu "Processor type and features"
253 source "kernel/time/Kconfig"
256 bool "Symmetric multi-processing support"
258 This enables support for systems with more than one CPU. If you have
259 a system with only one CPU, like most personal computers, say N. If
260 you have a system with more than one CPU, say Y.
262 If you say N here, the kernel will run on single and multiprocessor
263 machines, but will use only one CPU of a multiprocessor machine. If
264 you say Y here, the kernel will run on many, but not all,
265 singleprocessor machines. On a singleprocessor machine, the kernel
266 will run faster if you say N here.
268 Note that if you say Y here and choose architecture "586" or
269 "Pentium" under "Processor family", the kernel will not work on 486
270 architectures. Similarly, multiprocessor kernels for the "PPro"
271 architecture may not work on all Pentium based boards.
273 People using multiprocessor machines who say Y here should also say
274 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
275 Management" code will be disabled if you say Y here.
277 See also <file:Documentation/i386/IO-APIC.txt>,
278 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
279 <http://www.tldp.org/docs.html#howto>.
281 If you don't know what to do here, say N.
284 bool "Support x2apic"
285 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
287 This enables x2apic support on CPUs that have this feature.
289 This allows 32-bit apic IDs (so it can support very large systems),
290 and accesses the local apic via MSRs not via mmio.
292 If you don't know what to do here, say N.
295 bool "Enable MPS table" if ACPI
297 depends on X86_LOCAL_APIC
299 For old smp systems that do not have proper acpi support. Newer systems
300 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
303 bool "Support for big SMP systems with more than 8 CPUs"
304 depends on X86_32 && SMP
306 This option is needed for the systems that have more than 8 CPUs
309 config X86_EXTENDED_PLATFORM
310 bool "Support for extended (non-PC) x86 platforms"
313 If you disable this option then the kernel will only support
314 standard PC platforms. (which covers the vast majority of
317 If you enable this option then you'll be able to select support
318 for the following (non-PC) 32 bit x86 platforms:
322 SGI 320/540 (Visual Workstation)
323 Summit/EXA (IBM x440)
324 Unisys ES7000 IA32 series
325 Moorestown MID devices
327 If you have one of these systems, or if you want to build a
328 generic distribution kernel, say Y here - otherwise say N.
332 config X86_EXTENDED_PLATFORM
333 bool "Support for extended (non-PC) x86 platforms"
336 If you disable this option then the kernel will only support
337 standard PC platforms. (which covers the vast majority of
340 If you enable this option then you'll be able to select support
341 for the following (non-PC) 64 bit x86 platforms:
345 If you have one of these systems, or if you want to build a
346 generic distribution kernel, say Y here - otherwise say N.
348 # This is an alphabetically sorted list of 64 bit extended platforms
349 # Please maintain the alphabetic order if and when there are additions
353 select PARAVIRT_GUEST
355 depends on X86_64 && PCI
356 depends on X86_EXTENDED_PLATFORM
358 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
359 supposed to run on these EM64T-based machines. Only choose this option
360 if you have one of these machines.
363 bool "SGI Ultraviolet"
365 depends on X86_EXTENDED_PLATFORM
367 depends on X86_X2APIC
369 This option is needed in order to support SGI Ultraviolet systems.
370 If you don't have one of these, you should say N here.
372 # Following is an alphabetically sorted list of 32 bit extended platforms
373 # Please maintain the alphabetic order if and when there are additions
378 depends on X86_EXTENDED_PLATFORM
380 Select this for an AMD Elan processor.
382 Do not use this option for K6/Athlon/Opteron processors!
384 If unsure, choose "PC-compatible" instead.
387 bool "CE4100 TV platform"
389 depends on PCI_GODIRECT
391 depends on X86_EXTENDED_PLATFORM
392 select X86_REBOOTFIXUPS
394 select OF_EARLY_FLATTREE
396 Select for the Intel CE media processor (CE4100) SOC.
397 This option compiles in support for the CE4100 SOC for settop
398 boxes and media devices.
401 bool "Moorestown MID platform"
405 depends on X86_EXTENDED_PLATFORM
406 depends on X86_IO_APIC
411 select X86_PLATFORM_DEVICES
413 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
414 Internet Device(MID) platform. Moorestown consists of two chips:
415 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
416 Unlike standard x86 PCs, Moorestown does not have many legacy devices
417 nor standard legacy replacement devices/features. e.g. Moorestown does
418 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
421 bool "RDC R-321x SoC"
423 depends on X86_EXTENDED_PLATFORM
425 select X86_REBOOTFIXUPS
427 This option is needed for RDC R-321x system-on-chip, also known
429 If you don't have one of these chips, you should say N here.
431 config X86_32_NON_STANDARD
432 bool "Support non-standard 32-bit SMP architectures"
433 depends on X86_32 && SMP
434 depends on X86_EXTENDED_PLATFORM
436 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
437 subarchitectures. It is intended for a generic binary kernel.
438 if you select them all, kernel will probe it one by one. and will
441 # Alphabetically sorted list of Non standard 32 bit platforms
444 bool "NUMAQ (IBM/Sequent)"
445 depends on X86_32_NON_STANDARD
450 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
451 NUMA multiquad box. This changes the way that processors are
452 bootstrapped, and uses Clustered Logical APIC addressing mode instead
453 of Flat Logical. You will need a new lynxer.elf file to flash your
454 firmware with - send email to <Martin.Bligh@us.ibm.com>.
456 config X86_SUPPORTS_MEMORY_FAILURE
458 # MCE code calls memory_failure():
460 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
461 depends on !X86_NUMAQ
462 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
463 depends on X86_64 || !SPARSEMEM
464 select ARCH_SUPPORTS_MEMORY_FAILURE
467 bool "SGI 320/540 (Visual Workstation)"
468 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
469 depends on X86_32_NON_STANDARD
471 The SGI Visual Workstation series is an IA32-based workstation
472 based on SGI systems chips with some legacy PC hardware attached.
474 Say Y here to create a kernel to run on the SGI 320 or 540.
476 A kernel compiled for the Visual Workstation will run on general
477 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
480 bool "Summit/EXA (IBM x440)"
481 depends on X86_32_NON_STANDARD
483 This option is needed for IBM systems that use the Summit/EXA chipset.
484 In particular, it is needed for the x440.
487 bool "Unisys ES7000 IA32 series"
488 depends on X86_32_NON_STANDARD && X86_BIGSMP
490 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
491 supposed to run on an IA32-based Unisys ES7000 system.
494 tristate "Eurobraille/Iris poweroff module"
497 The Iris machines from EuroBraille do not have APM or ACPI support
498 to shut themselves down properly. A special I/O sequence is
499 needed to do so, which is what this module does at
502 This is only for Iris machines from EuroBraille.
506 config SCHED_OMIT_FRAME_POINTER
508 prompt "Single-depth WCHAN output"
511 Calculate simpler /proc/<PID>/wchan values. If this option
512 is disabled then wchan values will recurse back to the
513 caller function. This provides more accurate wchan values,
514 at the expense of slightly more scheduling overhead.
516 If in doubt, say "Y".
518 menuconfig PARAVIRT_GUEST
519 bool "Paravirtualized guest support"
521 Say Y here to get to see options related to running Linux under
522 various hypervisors. This option alone does not add any kernel code.
524 If you say N, all options in this submenu will be skipped and disabled.
528 source "arch/x86/xen/Kconfig"
531 bool "KVM paravirtualized clock"
533 select PARAVIRT_CLOCK
535 Turning on this option will allow you to run a paravirtualized clock
536 when running over the KVM hypervisor. Instead of relying on a PIT
537 (or probably other) emulation by the underlying device model, the host
538 provides the guest with timing infrastructure such as time of day, and
542 bool "KVM Guest support"
545 This option enables various optimizations for running under the KVM
548 source "arch/x86/lguest/Kconfig"
551 bool "Enable paravirtualization code"
553 This changes the kernel so it can modify itself when it is run
554 under a hypervisor, potentially improving performance significantly
555 over full virtualization. However, when run without a hypervisor
556 the kernel is theoretically slower and slightly larger.
558 config PARAVIRT_SPINLOCKS
559 bool "Paravirtualization layer for spinlocks"
560 depends on PARAVIRT && SMP && EXPERIMENTAL
562 Paravirtualized spinlocks allow a pvops backend to replace the
563 spinlock implementation with something virtualization-friendly
564 (for example, block the virtual CPU rather than spinning).
566 Unfortunately the downside is an up to 5% performance hit on
567 native kernels, with various workloads.
569 If you are unsure how to answer this question, answer N.
571 config PARAVIRT_CLOCK
576 config PARAVIRT_DEBUG
577 bool "paravirt-ops debugging"
578 depends on PARAVIRT && DEBUG_KERNEL
580 Enable to debug paravirt_ops internals. Specifically, BUG if
581 a paravirt_op is missing when it is called.
589 This option adds a kernel parameter 'memtest', which allows memtest
591 memtest=0, mean disabled; -- default
592 memtest=1, mean do 1 test pattern;
594 memtest=4, mean do 4 test patterns.
595 If you are unsure how to answer this question, answer N.
597 config X86_SUMMIT_NUMA
599 depends on X86_32 && NUMA && X86_32_NON_STANDARD
601 config X86_CYCLONE_TIMER
603 depends on X86_32_NON_STANDARD
605 source "arch/x86/Kconfig.cpu"
609 prompt "HPET Timer Support" if X86_32
611 Use the IA-PC HPET (High Precision Event Timer) to manage
612 time in preference to the PIT and RTC, if a HPET is
614 HPET is the next generation timer replacing legacy 8254s.
615 The HPET provides a stable time base on SMP
616 systems, unlike the TSC, but it is more expensive to access,
617 as it is off-chip. You can find the HPET spec at
618 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
620 You can safely choose Y here. However, HPET will only be
621 activated if the platform and the BIOS support this feature.
622 Otherwise the 8254 will be used for timing services.
624 Choose N to continue using the legacy 8254 timer.
626 config HPET_EMULATE_RTC
628 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
632 prompt "Langwell APB Timer Support" if X86_MRST
634 APB timer is the replacement for 8254, HPET on X86 MID platforms.
635 The APBT provides a stable time base on SMP
636 systems, unlike the TSC, but it is more expensive to access,
637 as it is off-chip. APB timers are always running regardless of CPU
638 C states, they are used as per CPU clockevent device when possible.
640 # Mark as expert because too many people got it wrong.
641 # The code disables itself when not needed.
644 bool "Enable DMI scanning" if EXPERT
646 Enabled scanning of DMI to identify machine quirks. Say Y
647 here unless you have verified that your setup is not
648 affected by entries in the DMI blacklist. Required by PNP
652 bool "GART IOMMU support" if EXPERT
655 depends on X86_64 && PCI && AMD_NB
657 Support for full DMA access of devices with 32bit memory access only
658 on systems with more than 3GB. This is usually needed for USB,
659 sound, many IDE/SATA chipsets and some other devices.
660 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
661 based hardware IOMMU and a software bounce buffer based IOMMU used
662 on Intel systems and as fallback.
663 The code is only active when needed (enough memory and limited
664 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
668 bool "IBM Calgary IOMMU support"
670 depends on X86_64 && PCI && EXPERIMENTAL
672 Support for hardware IOMMUs in IBM's xSeries x366 and x460
673 systems. Needed to run systems with more than 3GB of memory
674 properly with 32-bit PCI devices that do not support DAC
675 (Double Address Cycle). Calgary also supports bus level
676 isolation, where all DMAs pass through the IOMMU. This
677 prevents them from going anywhere except their intended
678 destination. This catches hard-to-find kernel bugs and
679 mis-behaving drivers and devices that do not use the DMA-API
680 properly to set up their DMA buffers. The IOMMU can be
681 turned off at boot time with the iommu=off parameter.
682 Normally the kernel will make the right choice by itself.
685 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
687 prompt "Should Calgary be enabled by default?"
688 depends on CALGARY_IOMMU
690 Should Calgary be enabled by default? if you choose 'y', Calgary
691 will be used (if it exists). If you choose 'n', Calgary will not be
692 used even if it exists. If you choose 'n' and would like to use
693 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
697 bool "AMD IOMMU support"
700 depends on X86_64 && PCI && ACPI
702 With this option you can enable support for AMD IOMMU hardware in
703 your system. An IOMMU is a hardware component which provides
704 remapping of DMA memory accesses from devices. With an AMD IOMMU you
705 can isolate the the DMA memory of different devices and protect the
706 system from misbehaving device drivers or hardware.
708 You can find out if your system has an AMD IOMMU if you look into
709 your BIOS for an option to enable it or if you have an IVRS ACPI
712 config AMD_IOMMU_STATS
713 bool "Export AMD IOMMU statistics to debugfs"
717 This option enables code in the AMD IOMMU driver to collect various
718 statistics about whats happening in the driver and exports that
719 information to userspace via debugfs.
722 # need this always selected by IOMMU for the VIA workaround
726 Support for software bounce buffers used on x86-64 systems
727 which don't have a hardware IOMMU (e.g. the current generation
728 of Intel's x86-64 CPUs). Using this PCI devices which can only
729 access 32-bits of memory can be used on systems with more than
730 3 GB of memory. If unsure, say Y.
733 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
736 def_bool (AMD_IOMMU || DMAR)
739 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
740 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
741 select CPUMASK_OFFSTACK
743 Enable maximum number of CPUS and NUMA Nodes for this architecture.
747 int "Maximum number of CPUs" if SMP && !MAXSMP
748 range 2 8 if SMP && X86_32 && !X86_BIGSMP
749 range 2 512 if SMP && !MAXSMP
751 default "4096" if MAXSMP
752 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
755 This allows you to specify the maximum number of CPUs which this
756 kernel will support. The maximum supported value is 512 and the
757 minimum value which makes sense is 2.
759 This is purely to save memory - each supported CPU adds
760 approximately eight kilobytes to the kernel image.
763 bool "SMT (Hyperthreading) scheduler support"
766 SMT scheduler support improves the CPU scheduler's decision making
767 when dealing with Intel Pentium 4 chips with HyperThreading at a
768 cost of slightly increased overhead in some places. If unsure say
773 prompt "Multi-core scheduler support"
776 Multi-core scheduler support improves the CPU scheduler's decision
777 making when dealing with multi-core CPU chips at a cost of slightly
778 increased overhead in some places. If unsure say N here.
780 config IRQ_TIME_ACCOUNTING
781 bool "Fine granularity task level IRQ time accounting"
784 Select this option to enable fine granularity task irq time
785 accounting. This is done by reading a timestamp on each
786 transitions between softirq and hardirq state, so there can be a
787 small performance impact.
789 If in doubt, say N here.
791 source "kernel/Kconfig.preempt"
794 bool "Local APIC support on uniprocessors"
795 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
797 A local APIC (Advanced Programmable Interrupt Controller) is an
798 integrated interrupt controller in the CPU. If you have a single-CPU
799 system which has a processor with a local APIC, you can say Y here to
800 enable and use it. If you say Y here even though your machine doesn't
801 have a local APIC, then the kernel will still run with no slowdown at
802 all. The local APIC supports CPU-generated self-interrupts (timer,
803 performance counters), and the NMI watchdog which detects hard
807 bool "IO-APIC support on uniprocessors"
808 depends on X86_UP_APIC
810 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
811 SMP-capable replacement for PC-style interrupt controllers. Most
812 SMP systems and many recent uniprocessor systems have one.
814 If you have a single-CPU system with an IO-APIC, you can say Y here
815 to use it. If you say Y here even though your machine doesn't have
816 an IO-APIC, then the kernel will still run with no slowdown at all.
818 config X86_LOCAL_APIC
820 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
824 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
826 config X86_VISWS_APIC
828 depends on X86_32 && X86_VISWS
830 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
831 bool "Reroute for broken boot IRQs"
832 depends on X86_IO_APIC
834 This option enables a workaround that fixes a source of
835 spurious interrupts. This is recommended when threaded
836 interrupt handling is used on systems where the generation of
837 superfluous "boot interrupts" cannot be disabled.
839 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
840 entry in the chipset's IO-APIC is masked (as, e.g. the RT
841 kernel does during interrupt handling). On chipsets where this
842 boot IRQ generation cannot be disabled, this workaround keeps
843 the original IRQ line masked so that only the equivalent "boot
844 IRQ" is delivered to the CPUs. The workaround also tells the
845 kernel to set up the IRQ handler on the boot IRQ line. In this
846 way only one interrupt is delivered to the kernel. Otherwise
847 the spurious second interrupt may cause the kernel to bring
848 down (vital) interrupt lines.
850 Only affects "broken" chipsets. Interrupt sharing may be
851 increased on these systems.
854 bool "Machine Check / overheating reporting"
856 Machine Check support allows the processor to notify the
857 kernel if it detects a problem (e.g. overheating, data corruption).
858 The action the kernel takes depends on the severity of the problem,
859 ranging from warning messages to halting the machine.
863 prompt "Intel MCE features"
864 depends on X86_MCE && X86_LOCAL_APIC
866 Additional support for intel specific MCE features such as
871 prompt "AMD MCE features"
872 depends on X86_MCE && X86_LOCAL_APIC
874 Additional support for AMD specific MCE features such as
875 the DRAM Error Threshold.
877 config X86_ANCIENT_MCE
878 bool "Support for old Pentium 5 / WinChip machine checks"
879 depends on X86_32 && X86_MCE
881 Include support for machine check handling on old Pentium 5 or WinChip
882 systems. These typically need to be enabled explicitely on the command
885 config X86_MCE_THRESHOLD
886 depends on X86_MCE_AMD || X86_MCE_INTEL
889 config X86_MCE_INJECT
891 tristate "Machine check injector support"
893 Provide support for injecting machine checks for testing purposes.
894 If you don't know what a machine check is and you don't do kernel
895 QA it is safe to say n.
897 config X86_THERMAL_VECTOR
899 depends on X86_MCE_INTEL
902 bool "Enable VM86 support" if EXPERT
906 This option is required by programs like DOSEMU to run 16-bit legacy
907 code on X86 processors. It also may be needed by software like
908 XFree86 to initialize some video cards via BIOS. Disabling this
909 option saves about 6k.
912 tristate "Toshiba Laptop support"
915 This adds a driver to safely access the System Management Mode of
916 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
917 not work on models with a Phoenix BIOS. The System Management Mode
918 is used to set the BIOS and power saving options on Toshiba portables.
920 For information on utilities to make use of this driver see the
921 Toshiba Linux utilities web site at:
922 <http://www.buzzard.org.uk/toshiba/>.
924 Say Y if you intend to run this kernel on a Toshiba portable.
928 tristate "Dell laptop support"
930 This adds a driver to safely access the System Management Mode
931 of the CPU on the Dell Inspiron 8000. The System Management Mode
932 is used to read cpu temperature and cooling fan status and to
933 control the fans on the I8K portables.
935 This driver has been tested only on the Inspiron 8000 but it may
936 also work with other Dell laptops. You can force loading on other
937 models by passing the parameter `force=1' to the module. Use at
940 For information on utilities to make use of this driver see the
941 I8K Linux utilities web site at:
942 <http://people.debian.org/~dz/i8k/>
944 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
947 config X86_REBOOTFIXUPS
948 bool "Enable X86 board specific fixups for reboot"
951 This enables chipset and/or board specific fixups to be done
952 in order to get reboot to work correctly. This is only needed on
953 some combinations of hardware and BIOS. The symptom, for which
954 this config is intended, is when reboot ends with a stalled/hung
957 Currently, the only fixup is for the Geode machines using
958 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
960 Say Y if you want to enable the fixup. Currently, it's safe to
961 enable this option even if you don't need it.
965 tristate "/dev/cpu/microcode - microcode support"
968 If you say Y here, you will be able to update the microcode on
969 certain Intel and AMD processors. The Intel support is for the
970 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
971 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
972 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
973 You will obviously need the actual microcode binary data itself
974 which is not shipped with the Linux kernel.
976 This option selects the general module only, you need to select
977 at least one vendor specific module as well.
979 To compile this driver as a module, choose M here: the
980 module will be called microcode.
982 config MICROCODE_INTEL
983 bool "Intel microcode patch loading support"
988 This options enables microcode patch loading support for Intel
991 For latest news and information on obtaining all the required
992 Intel ingredients for this driver, check:
993 <http://www.urbanmyth.org/microcode/>.
996 bool "AMD microcode patch loading support"
1000 If you select this option, microcode patch loading support for AMD
1001 processors will be enabled.
1003 config MICROCODE_OLD_INTERFACE
1005 depends on MICROCODE
1008 tristate "/dev/cpu/*/msr - Model-specific register support"
1010 This device gives privileged processes access to the x86
1011 Model-Specific Registers (MSRs). It is a character device with
1012 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1013 MSR accesses are directed to a specific CPU on multi-processor
1017 tristate "/dev/cpu/*/cpuid - CPU information support"
1019 This device gives processes access to the x86 CPUID instruction to
1020 be executed on a specific processor. It is a character device
1021 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1025 prompt "High Memory Support"
1026 default HIGHMEM64G if X86_NUMAQ
1032 depends on !X86_NUMAQ
1034 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1035 However, the address space of 32-bit x86 processors is only 4
1036 Gigabytes large. That means that, if you have a large amount of
1037 physical memory, not all of it can be "permanently mapped" by the
1038 kernel. The physical memory that's not permanently mapped is called
1041 If you are compiling a kernel which will never run on a machine with
1042 more than 1 Gigabyte total physical RAM, answer "off" here (default
1043 choice and suitable for most users). This will result in a "3GB/1GB"
1044 split: 3GB are mapped so that each process sees a 3GB virtual memory
1045 space and the remaining part of the 4GB virtual memory space is used
1046 by the kernel to permanently map as much physical memory as
1049 If the machine has between 1 and 4 Gigabytes physical RAM, then
1052 If more than 4 Gigabytes is used then answer "64GB" here. This
1053 selection turns Intel PAE (Physical Address Extension) mode on.
1054 PAE implements 3-level paging on IA32 processors. PAE is fully
1055 supported by Linux, PAE mode is implemented on all recent Intel
1056 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1057 then the kernel will not boot on CPUs that don't support PAE!
1059 The actual amount of total physical memory will either be
1060 auto detected or can be forced by using a kernel command line option
1061 such as "mem=256M". (Try "man bootparam" or see the documentation of
1062 your boot loader (lilo or loadlin) about how to pass options to the
1063 kernel at boot time.)
1065 If unsure, say "off".
1069 depends on !X86_NUMAQ
1071 Select this if you have a 32-bit processor and between 1 and 4
1072 gigabytes of physical RAM.
1076 depends on !M386 && !M486
1079 Select this if you have a 32-bit processor and more than 4
1080 gigabytes of physical RAM.
1085 depends on EXPERIMENTAL
1086 prompt "Memory split" if EXPERT
1090 Select the desired split between kernel and user memory.
1092 If the address range available to the kernel is less than the
1093 physical memory installed, the remaining memory will be available
1094 as "high memory". Accessing high memory is a little more costly
1095 than low memory, as it needs to be mapped into the kernel first.
1096 Note that increasing the kernel address space limits the range
1097 available to user programs, making the address space there
1098 tighter. Selecting anything other than the default 3G/1G split
1099 will also likely make your kernel incompatible with binary-only
1102 If you are not absolutely sure what you are doing, leave this
1106 bool "3G/1G user/kernel split"
1107 config VMSPLIT_3G_OPT
1109 bool "3G/1G user/kernel split (for full 1G low memory)"
1111 bool "2G/2G user/kernel split"
1112 config VMSPLIT_2G_OPT
1114 bool "2G/2G user/kernel split (for full 2G low memory)"
1116 bool "1G/3G user/kernel split"
1121 default 0xB0000000 if VMSPLIT_3G_OPT
1122 default 0x80000000 if VMSPLIT_2G
1123 default 0x78000000 if VMSPLIT_2G_OPT
1124 default 0x40000000 if VMSPLIT_1G
1130 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1133 bool "PAE (Physical Address Extension) Support"
1134 depends on X86_32 && !HIGHMEM4G
1136 PAE is required for NX support, and furthermore enables
1137 larger swapspace support for non-overcommit purposes. It
1138 has the cost of more pagetable lookup overhead, and also
1139 consumes more pagetable space per process.
1141 config ARCH_PHYS_ADDR_T_64BIT
1142 def_bool X86_64 || X86_PAE
1144 config ARCH_DMA_ADDR_T_64BIT
1145 def_bool X86_64 || HIGHMEM64G
1147 config DIRECT_GBPAGES
1148 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1152 Allow the kernel linear mapping to use 1GB pages on CPUs that
1153 support it. This can improve the kernel's performance a tiny bit by
1154 reducing TLB pressure. If in doubt, say "Y".
1156 # Common NUMA Features
1158 bool "Numa Memory Allocation and Scheduler Support"
1160 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1161 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1163 Enable NUMA (Non Uniform Memory Access) support.
1165 The kernel will try to allocate memory used by a CPU on the
1166 local memory controller of the CPU and add some more
1167 NUMA awareness to the kernel.
1169 For 64-bit this is recommended if the system is Intel Core i7
1170 (or later), AMD Opteron, or EM64T NUMA.
1172 For 32-bit this is only needed on (rare) 32-bit-only platforms
1173 that support NUMA topologies, such as NUMAQ / Summit, or if you
1174 boot a 32-bit kernel on a 64-bit NUMA platform.
1176 Otherwise, you should say N.
1178 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1179 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1183 prompt "Old style AMD Opteron NUMA detection"
1184 depends on NUMA && PCI
1186 Enable AMD NUMA node topology detection. You should say Y here if
1187 you have a multi processor AMD system. This uses an old method to
1188 read the NUMA configuration directly from the builtin Northbridge
1189 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1190 which also takes priority if both are compiled in.
1192 config X86_64_ACPI_NUMA
1194 prompt "ACPI NUMA detection"
1195 depends on X86_64 && NUMA && ACPI && PCI
1198 Enable ACPI SRAT based node topology detection.
1200 # Some NUMA nodes have memory ranges that span
1201 # other nodes. Even though a pfn is valid and
1202 # between a node's start and end pfns, it may not
1203 # reside on that node. See memmap_init_zone()
1205 config NODES_SPAN_OTHER_NODES
1207 depends on X86_64_ACPI_NUMA
1210 bool "NUMA emulation"
1213 Enable NUMA emulation. A flat machine will be split
1214 into virtual nodes when booted with "numa=fake=N", where N is the
1215 number of nodes. This is only useful for debugging.
1218 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1220 default "10" if MAXSMP
1221 default "6" if X86_64
1222 default "4" if X86_NUMAQ
1224 depends on NEED_MULTIPLE_NODES
1226 Specify the maximum number of NUMA Nodes available on the target
1227 system. Increases memory reserved to accommodate various tables.
1229 config HAVE_ARCH_BOOTMEM
1231 depends on X86_32 && NUMA
1233 config HAVE_ARCH_ALLOC_REMAP
1235 depends on X86_32 && NUMA
1237 config ARCH_HAVE_MEMORY_PRESENT
1239 depends on X86_32 && DISCONTIGMEM
1241 config NEED_NODE_MEMMAP_SIZE
1243 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1245 config ARCH_FLATMEM_ENABLE
1247 depends on X86_32 && !NUMA
1249 config ARCH_DISCONTIGMEM_ENABLE
1251 depends on NUMA && X86_32
1253 config ARCH_DISCONTIGMEM_DEFAULT
1255 depends on NUMA && X86_32
1257 config ARCH_SPARSEMEM_ENABLE
1259 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1260 select SPARSEMEM_STATIC if X86_32
1261 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1263 config ARCH_SPARSEMEM_DEFAULT
1267 config ARCH_SELECT_MEMORY_MODEL
1269 depends on ARCH_SPARSEMEM_ENABLE
1271 config ARCH_MEMORY_PROBE
1273 depends on MEMORY_HOTPLUG
1275 config ARCH_PROC_KCORE_TEXT
1277 depends on X86_64 && PROC_KCORE
1279 config ILLEGAL_POINTER_VALUE
1282 default 0xdead000000000000 if X86_64
1287 bool "Allocate 3rd-level pagetables from highmem"
1290 The VM uses one page table entry for each page of physical memory.
1291 For systems with a lot of RAM, this can be wasteful of precious
1292 low memory. Setting this option will put user-space page table
1293 entries in high memory.
1295 config X86_CHECK_BIOS_CORRUPTION
1296 bool "Check for low memory corruption"
1298 Periodically check for memory corruption in low memory, which
1299 is suspected to be caused by BIOS. Even when enabled in the
1300 configuration, it is disabled at runtime. Enable it by
1301 setting "memory_corruption_check=1" on the kernel command
1302 line. By default it scans the low 64k of memory every 60
1303 seconds; see the memory_corruption_check_size and
1304 memory_corruption_check_period parameters in
1305 Documentation/kernel-parameters.txt to adjust this.
1307 When enabled with the default parameters, this option has
1308 almost no overhead, as it reserves a relatively small amount
1309 of memory and scans it infrequently. It both detects corruption
1310 and prevents it from affecting the running system.
1312 It is, however, intended as a diagnostic tool; if repeatable
1313 BIOS-originated corruption always affects the same memory,
1314 you can use memmap= to prevent the kernel from using that
1317 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1318 bool "Set the default setting of memory_corruption_check"
1319 depends on X86_CHECK_BIOS_CORRUPTION
1322 Set whether the default state of memory_corruption_check is
1325 config X86_RESERVE_LOW
1326 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1330 Specify the amount of low memory to reserve for the BIOS.
1332 The first page contains BIOS data structures that the kernel
1333 must not use, so that page must always be reserved.
1335 By default we reserve the first 64K of physical RAM, as a
1336 number of BIOSes are known to corrupt that memory range
1337 during events such as suspend/resume or monitor cable
1338 insertion, so it must not be used by the kernel.
1340 You can set this to 4 if you are absolutely sure that you
1341 trust the BIOS to get all its memory reservations and usages
1342 right. If you know your BIOS have problems beyond the
1343 default 64K area, you can set this to 640 to avoid using the
1344 entire low memory range.
1346 If you have doubts about the BIOS (e.g. suspend/resume does
1347 not work or there's kernel crashes after certain hardware
1348 hotplug events) then you might want to enable
1349 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1350 typical corruption patterns.
1352 Leave this to the default value of 64 if you are unsure.
1354 config MATH_EMULATION
1356 prompt "Math emulation" if X86_32
1358 Linux can emulate a math coprocessor (used for floating point
1359 operations) if you don't have one. 486DX and Pentium processors have
1360 a math coprocessor built in, 486SX and 386 do not, unless you added
1361 a 487DX or 387, respectively. (The messages during boot time can
1362 give you some hints here ["man dmesg"].) Everyone needs either a
1363 coprocessor or this emulation.
1365 If you don't have a math coprocessor, you need to say Y here; if you
1366 say Y here even though you have a coprocessor, the coprocessor will
1367 be used nevertheless. (This behavior can be changed with the kernel
1368 command line option "no387", which comes handy if your coprocessor
1369 is broken. Try "man bootparam" or see the documentation of your boot
1370 loader (lilo or loadlin) about how to pass options to the kernel at
1371 boot time.) This means that it is a good idea to say Y here if you
1372 intend to use this kernel on different machines.
1374 More information about the internals of the Linux math coprocessor
1375 emulation can be found in <file:arch/x86/math-emu/README>.
1377 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1378 kernel, it won't hurt.
1382 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1384 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1385 the Memory Type Range Registers (MTRRs) may be used to control
1386 processor access to memory ranges. This is most useful if you have
1387 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1388 allows bus write transfers to be combined into a larger transfer
1389 before bursting over the PCI/AGP bus. This can increase performance
1390 of image write operations 2.5 times or more. Saying Y here creates a
1391 /proc/mtrr file which may be used to manipulate your processor's
1392 MTRRs. Typically the X server should use this.
1394 This code has a reasonably generic interface so that similar
1395 control registers on other processors can be easily supported
1398 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1399 Registers (ARRs) which provide a similar functionality to MTRRs. For
1400 these, the ARRs are used to emulate the MTRRs.
1401 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1402 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1403 write-combining. All of these processors are supported by this code
1404 and it makes sense to say Y here if you have one of them.
1406 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1407 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1408 can lead to all sorts of problems, so it's good to say Y here.
1410 You can safely say Y even if your machine doesn't have MTRRs, you'll
1411 just add about 9 KB to your kernel.
1413 See <file:Documentation/x86/mtrr.txt> for more information.
1415 config MTRR_SANITIZER
1417 prompt "MTRR cleanup support"
1420 Convert MTRR layout from continuous to discrete, so X drivers can
1421 add writeback entries.
1423 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1424 The largest mtrr entry size for a continuous block can be set with
1429 config MTRR_SANITIZER_ENABLE_DEFAULT
1430 int "MTRR cleanup enable value (0-1)"
1433 depends on MTRR_SANITIZER
1435 Enable mtrr cleanup default value
1437 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1438 int "MTRR cleanup spare reg num (0-7)"
1441 depends on MTRR_SANITIZER
1443 mtrr cleanup spare entries default, it can be changed via
1444 mtrr_spare_reg_nr=N on the kernel command line.
1448 prompt "x86 PAT support" if EXPERT
1451 Use PAT attributes to setup page level cache control.
1453 PATs are the modern equivalents of MTRRs and are much more
1454 flexible than MTRRs.
1456 Say N here if you see bootup problems (boot crash, boot hang,
1457 spontaneous reboots) or a non-working video driver.
1461 config ARCH_USES_PG_UNCACHED
1466 bool "EFI runtime service support"
1469 This enables the kernel to use EFI runtime services that are
1470 available (such as the EFI variable services).
1472 This option is only useful on systems that have EFI firmware.
1473 In addition, you should use the latest ELILO loader available
1474 at <http://elilo.sourceforge.net> in order to take advantage
1475 of EFI runtime services. However, even with this option, the
1476 resultant kernel should continue to boot on existing non-EFI
1481 prompt "Enable seccomp to safely compute untrusted bytecode"
1483 This kernel feature is useful for number crunching applications
1484 that may need to compute untrusted bytecode during their
1485 execution. By using pipes or other transports made available to
1486 the process as file descriptors supporting the read/write
1487 syscalls, it's possible to isolate those applications in
1488 their own address space using seccomp. Once seccomp is
1489 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1490 and the task is only allowed to execute a few safe syscalls
1491 defined by each seccomp mode.
1493 If unsure, say Y. Only embedded should say N here.
1495 config CC_STACKPROTECTOR
1496 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1498 This option turns on the -fstack-protector GCC feature. This
1499 feature puts, at the beginning of functions, a canary value on
1500 the stack just before the return address, and validates
1501 the value just before actually returning. Stack based buffer
1502 overflows (that need to overwrite this return address) now also
1503 overwrite the canary, which gets detected and the attack is then
1504 neutralized via a kernel panic.
1506 This feature requires gcc version 4.2 or above, or a distribution
1507 gcc with the feature backported. Older versions are automatically
1508 detected and for those versions, this configuration option is
1509 ignored. (and a warning is printed during bootup)
1511 source kernel/Kconfig.hz
1514 bool "kexec system call"
1516 kexec is a system call that implements the ability to shutdown your
1517 current kernel, and to start another kernel. It is like a reboot
1518 but it is independent of the system firmware. And like a reboot
1519 you can start any kernel with it, not just Linux.
1521 The name comes from the similarity to the exec system call.
1523 It is an ongoing process to be certain the hardware in a machine
1524 is properly shutdown, so do not be surprised if this code does not
1525 initially work for you. It may help to enable device hotplugging
1526 support. As of this writing the exact hardware interface is
1527 strongly in flux, so no good recommendation can be made.
1530 bool "kernel crash dumps"
1531 depends on X86_64 || (X86_32 && HIGHMEM)
1533 Generate crash dump after being started by kexec.
1534 This should be normally only set in special crash dump kernels
1535 which are loaded in the main kernel with kexec-tools into
1536 a specially reserved region and then later executed after
1537 a crash by kdump/kexec. The crash dump kernel must be compiled
1538 to a memory address not used by the main kernel or BIOS using
1539 PHYSICAL_START, or it must be built as a relocatable image
1540 (CONFIG_RELOCATABLE=y).
1541 For more details see Documentation/kdump/kdump.txt
1544 bool "kexec jump (EXPERIMENTAL)"
1545 depends on EXPERIMENTAL
1546 depends on KEXEC && HIBERNATION
1548 Jump between original kernel and kexeced kernel and invoke
1549 code in physical address mode via KEXEC
1551 config PHYSICAL_START
1552 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1555 This gives the physical address where the kernel is loaded.
1557 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1558 bzImage will decompress itself to above physical address and
1559 run from there. Otherwise, bzImage will run from the address where
1560 it has been loaded by the boot loader and will ignore above physical
1563 In normal kdump cases one does not have to set/change this option
1564 as now bzImage can be compiled as a completely relocatable image
1565 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1566 address. This option is mainly useful for the folks who don't want
1567 to use a bzImage for capturing the crash dump and want to use a
1568 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1569 to be specifically compiled to run from a specific memory area
1570 (normally a reserved region) and this option comes handy.
1572 So if you are using bzImage for capturing the crash dump,
1573 leave the value here unchanged to 0x1000000 and set
1574 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1575 for capturing the crash dump change this value to start of
1576 the reserved region. In other words, it can be set based on
1577 the "X" value as specified in the "crashkernel=YM@XM"
1578 command line boot parameter passed to the panic-ed
1579 kernel. Please take a look at Documentation/kdump/kdump.txt
1580 for more details about crash dumps.
1582 Usage of bzImage for capturing the crash dump is recommended as
1583 one does not have to build two kernels. Same kernel can be used
1584 as production kernel and capture kernel. Above option should have
1585 gone away after relocatable bzImage support is introduced. But it
1586 is present because there are users out there who continue to use
1587 vmlinux for dump capture. This option should go away down the
1590 Don't change this unless you know what you are doing.
1593 bool "Build a relocatable kernel"
1596 This builds a kernel image that retains relocation information
1597 so it can be loaded someplace besides the default 1MB.
1598 The relocations tend to make the kernel binary about 10% larger,
1599 but are discarded at runtime.
1601 One use is for the kexec on panic case where the recovery kernel
1602 must live at a different physical address than the primary
1605 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1606 it has been loaded at and the compile time physical address
1607 (CONFIG_PHYSICAL_START) is ignored.
1609 # Relocation on x86-32 needs some additional build support
1610 config X86_NEED_RELOCS
1612 depends on X86_32 && RELOCATABLE
1614 config PHYSICAL_ALIGN
1615 hex "Alignment value to which kernel should be aligned" if X86_32
1617 range 0x2000 0x1000000
1619 This value puts the alignment restrictions on physical address
1620 where kernel is loaded and run from. Kernel is compiled for an
1621 address which meets above alignment restriction.
1623 If bootloader loads the kernel at a non-aligned address and
1624 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1625 address aligned to above value and run from there.
1627 If bootloader loads the kernel at a non-aligned address and
1628 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1629 load address and decompress itself to the address it has been
1630 compiled for and run from there. The address for which kernel is
1631 compiled already meets above alignment restrictions. Hence the
1632 end result is that kernel runs from a physical address meeting
1633 above alignment restrictions.
1635 Don't change this unless you know what you are doing.
1638 bool "Support for hot-pluggable CPUs"
1639 depends on SMP && HOTPLUG
1641 Say Y here to allow turning CPUs off and on. CPUs can be
1642 controlled through /sys/devices/system/cpu.
1643 ( Note: power management support will enable this option
1644 automatically on SMP systems. )
1645 Say N if you want to disable CPU hotplug.
1649 prompt "Compat VDSO support"
1650 depends on X86_32 || IA32_EMULATION
1652 Map the 32-bit VDSO to the predictable old-style address too.
1654 Say N here if you are running a sufficiently recent glibc
1655 version (2.3.3 or later), to remove the high-mapped
1656 VDSO mapping and to exclusively use the randomized VDSO.
1661 bool "Built-in kernel command line"
1663 Allow for specifying boot arguments to the kernel at
1664 build time. On some systems (e.g. embedded ones), it is
1665 necessary or convenient to provide some or all of the
1666 kernel boot arguments with the kernel itself (that is,
1667 to not rely on the boot loader to provide them.)
1669 To compile command line arguments into the kernel,
1670 set this option to 'Y', then fill in the
1671 the boot arguments in CONFIG_CMDLINE.
1673 Systems with fully functional boot loaders (i.e. non-embedded)
1674 should leave this option set to 'N'.
1677 string "Built-in kernel command string"
1678 depends on CMDLINE_BOOL
1681 Enter arguments here that should be compiled into the kernel
1682 image and used at boot time. If the boot loader provides a
1683 command line at boot time, it is appended to this string to
1684 form the full kernel command line, when the system boots.
1686 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1687 change this behavior.
1689 In most cases, the command line (whether built-in or provided
1690 by the boot loader) should specify the device for the root
1693 config CMDLINE_OVERRIDE
1694 bool "Built-in command line overrides boot loader arguments"
1695 depends on CMDLINE_BOOL
1697 Set this option to 'Y' to have the kernel ignore the boot loader
1698 command line, and use ONLY the built-in command line.
1700 This is used to work around broken boot loaders. This should
1701 be set to 'N' under normal conditions.
1705 config ARCH_ENABLE_MEMORY_HOTPLUG
1707 depends on X86_64 || (X86_32 && HIGHMEM)
1709 config ARCH_ENABLE_MEMORY_HOTREMOVE
1711 depends on MEMORY_HOTPLUG
1713 config USE_PERCPU_NUMA_NODE_ID
1717 menu "Power management and ACPI options"
1719 config ARCH_HIBERNATION_HEADER
1721 depends on X86_64 && HIBERNATION
1723 source "kernel/power/Kconfig"
1725 source "drivers/acpi/Kconfig"
1727 source "drivers/sfi/Kconfig"
1731 depends on APM || APM_MODULE
1734 tristate "APM (Advanced Power Management) BIOS support"
1735 depends on X86_32 && PM_SLEEP
1737 APM is a BIOS specification for saving power using several different
1738 techniques. This is mostly useful for battery powered laptops with
1739 APM compliant BIOSes. If you say Y here, the system time will be
1740 reset after a RESUME operation, the /proc/apm device will provide
1741 battery status information, and user-space programs will receive
1742 notification of APM "events" (e.g. battery status change).
1744 If you select "Y" here, you can disable actual use of the APM
1745 BIOS by passing the "apm=off" option to the kernel at boot time.
1747 Note that the APM support is almost completely disabled for
1748 machines with more than one CPU.
1750 In order to use APM, you will need supporting software. For location
1751 and more information, read <file:Documentation/power/pm.txt> and the
1752 Battery Powered Linux mini-HOWTO, available from
1753 <http://www.tldp.org/docs.html#howto>.
1755 This driver does not spin down disk drives (see the hdparm(8)
1756 manpage ("man 8 hdparm") for that), and it doesn't turn off
1757 VESA-compliant "green" monitors.
1759 This driver does not support the TI 4000M TravelMate and the ACER
1760 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1761 desktop machines also don't have compliant BIOSes, and this driver
1762 may cause those machines to panic during the boot phase.
1764 Generally, if you don't have a battery in your machine, there isn't
1765 much point in using this driver and you should say N. If you get
1766 random kernel OOPSes or reboots that don't seem to be related to
1767 anything, try disabling/enabling this option (or disabling/enabling
1770 Some other things you should try when experiencing seemingly random,
1773 1) make sure that you have enough swap space and that it is
1775 2) pass the "no-hlt" option to the kernel
1776 3) switch on floating point emulation in the kernel and pass
1777 the "no387" option to the kernel
1778 4) pass the "floppy=nodma" option to the kernel
1779 5) pass the "mem=4M" option to the kernel (thereby disabling
1780 all but the first 4 MB of RAM)
1781 6) make sure that the CPU is not over clocked.
1782 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1783 8) disable the cache from your BIOS settings
1784 9) install a fan for the video card or exchange video RAM
1785 10) install a better fan for the CPU
1786 11) exchange RAM chips
1787 12) exchange the motherboard.
1789 To compile this driver as a module, choose M here: the
1790 module will be called apm.
1794 config APM_IGNORE_USER_SUSPEND
1795 bool "Ignore USER SUSPEND"
1797 This option will ignore USER SUSPEND requests. On machines with a
1798 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1799 series notebooks, it is necessary to say Y because of a BIOS bug.
1801 config APM_DO_ENABLE
1802 bool "Enable PM at boot time"
1804 Enable APM features at boot time. From page 36 of the APM BIOS
1805 specification: "When disabled, the APM BIOS does not automatically
1806 power manage devices, enter the Standby State, enter the Suspend
1807 State, or take power saving steps in response to CPU Idle calls."
1808 This driver will make CPU Idle calls when Linux is idle (unless this
1809 feature is turned off -- see "Do CPU IDLE calls", below). This
1810 should always save battery power, but more complicated APM features
1811 will be dependent on your BIOS implementation. You may need to turn
1812 this option off if your computer hangs at boot time when using APM
1813 support, or if it beeps continuously instead of suspending. Turn
1814 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1815 T400CDT. This is off by default since most machines do fine without
1819 bool "Make CPU Idle calls when idle"
1821 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1822 On some machines, this can activate improved power savings, such as
1823 a slowed CPU clock rate, when the machine is idle. These idle calls
1824 are made after the idle loop has run for some length of time (e.g.,
1825 333 mS). On some machines, this will cause a hang at boot time or
1826 whenever the CPU becomes idle. (On machines with more than one CPU,
1827 this option does nothing.)
1829 config APM_DISPLAY_BLANK
1830 bool "Enable console blanking using APM"
1832 Enable console blanking using the APM. Some laptops can use this to
1833 turn off the LCD backlight when the screen blanker of the Linux
1834 virtual console blanks the screen. Note that this is only used by
1835 the virtual console screen blanker, and won't turn off the backlight
1836 when using the X Window system. This also doesn't have anything to
1837 do with your VESA-compliant power-saving monitor. Further, this
1838 option doesn't work for all laptops -- it might not turn off your
1839 backlight at all, or it might print a lot of errors to the console,
1840 especially if you are using gpm.
1842 config APM_ALLOW_INTS
1843 bool "Allow interrupts during APM BIOS calls"
1845 Normally we disable external interrupts while we are making calls to
1846 the APM BIOS as a measure to lessen the effects of a badly behaving
1847 BIOS implementation. The BIOS should reenable interrupts if it
1848 needs to. Unfortunately, some BIOSes do not -- especially those in
1849 many of the newer IBM Thinkpads. If you experience hangs when you
1850 suspend, try setting this to Y. Otherwise, say N.
1854 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1856 source "drivers/cpuidle/Kconfig"
1858 source "drivers/idle/Kconfig"
1863 menu "Bus options (PCI etc.)"
1868 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1870 Find out whether you have a PCI motherboard. PCI is the name of a
1871 bus system, i.e. the way the CPU talks to the other stuff inside
1872 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1873 VESA. If you have PCI, say Y, otherwise N.
1876 prompt "PCI access mode"
1877 depends on X86_32 && PCI
1880 On PCI systems, the BIOS can be used to detect the PCI devices and
1881 determine their configuration. However, some old PCI motherboards
1882 have BIOS bugs and may crash if this is done. Also, some embedded
1883 PCI-based systems don't have any BIOS at all. Linux can also try to
1884 detect the PCI hardware directly without using the BIOS.
1886 With this option, you can specify how Linux should detect the
1887 PCI devices. If you choose "BIOS", the BIOS will be used,
1888 if you choose "Direct", the BIOS won't be used, and if you
1889 choose "MMConfig", then PCI Express MMCONFIG will be used.
1890 If you choose "Any", the kernel will try MMCONFIG, then the
1891 direct access method and falls back to the BIOS if that doesn't
1892 work. If unsure, go with the default, which is "Any".
1897 config PCI_GOMMCONFIG
1914 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1916 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1919 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1923 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1927 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1931 depends on PCI && XEN
1939 bool "Support mmconfig PCI config space access"
1940 depends on X86_64 && PCI && ACPI
1942 config PCI_CNB20LE_QUIRK
1943 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1945 depends on PCI && EXPERIMENTAL
1947 Read the PCI windows out of the CNB20LE host bridge. This allows
1948 PCI hotplug to work on systems with the CNB20LE chipset which do
1951 There's no public spec for this chipset, and this functionality
1952 is known to be incomplete.
1954 You should say N unless you know you need this.
1957 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1958 depends on PCI_MSI && ACPI && EXPERIMENTAL
1960 DMA remapping (DMAR) devices support enables independent address
1961 translations for Direct Memory Access (DMA) from devices.
1962 These DMA remapping devices are reported via ACPI tables
1963 and include PCI device scope covered by these DMA
1966 config DMAR_DEFAULT_ON
1968 prompt "Enable DMA Remapping Devices by default"
1971 Selecting this option will enable a DMAR device at boot time if
1972 one is found. If this option is not selected, DMAR support can
1973 be enabled by passing intel_iommu=on to the kernel. It is
1974 recommended you say N here while the DMAR code remains
1977 config DMAR_BROKEN_GFX_WA
1978 bool "Workaround broken graphics drivers (going away soon)"
1979 depends on DMAR && BROKEN
1981 Current Graphics drivers tend to use physical address
1982 for DMA and avoid using DMA APIs. Setting this config
1983 option permits the IOMMU driver to set a unity map for
1984 all the OS-visible memory. Hence the driver can continue
1985 to use physical addresses for DMA, at least until this
1986 option is removed in the 2.6.32 kernel.
1988 config DMAR_FLOPPY_WA
1992 Floppy disk drivers are known to bypass DMA API calls
1993 thereby failing to work when IOMMU is enabled. This
1994 workaround will setup a 1:1 mapping for the first
1995 16MiB to make floppy (an ISA device) work.
1998 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1999 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
2001 Supports Interrupt remapping for IO-APIC and MSI devices.
2002 To use x2apic mode in the CPU's which support x2APIC enhancements or
2003 to support platforms with CPU's having > 8 bit APIC ID, say Y.
2005 source "drivers/pci/pcie/Kconfig"
2007 source "drivers/pci/Kconfig"
2009 # x86_64 have no ISA slots, but can have ISA-style DMA.
2011 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2014 Enables ISA-style DMA support for devices requiring such controllers.
2022 Find out whether you have ISA slots on your motherboard. ISA is the
2023 name of a bus system, i.e. the way the CPU talks to the other stuff
2024 inside your box. Other bus systems are PCI, EISA, MicroChannel
2025 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2026 newer boards don't support it. If you have ISA, say Y, otherwise N.
2032 The Extended Industry Standard Architecture (EISA) bus was
2033 developed as an open alternative to the IBM MicroChannel bus.
2035 The EISA bus provided some of the features of the IBM MicroChannel
2036 bus while maintaining backward compatibility with cards made for
2037 the older ISA bus. The EISA bus saw limited use between 1988 and
2038 1995 when it was made obsolete by the PCI bus.
2040 Say Y here if you are building a kernel for an EISA-based machine.
2044 source "drivers/eisa/Kconfig"
2049 MicroChannel Architecture is found in some IBM PS/2 machines and
2050 laptops. It is a bus system similar to PCI or ISA. See
2051 <file:Documentation/mca.txt> (and especially the web page given
2052 there) before attempting to build an MCA bus kernel.
2054 source "drivers/mca/Kconfig"
2057 tristate "NatSemi SCx200 support"
2059 This provides basic support for National Semiconductor's
2060 (now AMD's) Geode processors. The driver probes for the
2061 PCI-IDs of several on-chip devices, so its a good dependency
2062 for other scx200_* drivers.
2064 If compiled as a module, the driver is named scx200.
2066 config SCx200HR_TIMER
2067 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2071 This driver provides a clocksource built upon the on-chip
2072 27MHz high-resolution timer. Its also a workaround for
2073 NSC Geode SC-1100's buggy TSC, which loses time when the
2074 processor goes idle (as is done by the scheduler). The
2075 other workaround is idle=poll boot option.
2078 bool "One Laptop Per Child support"
2082 select OF_PROMTREE if PROC_DEVICETREE
2084 Add support for detecting the unique features of the OLPC
2088 tristate "OLPC XO-1 support"
2089 depends on OLPC && MFD_CS5535
2091 Add support for non-essential features of the OLPC XO-1 laptop.
2097 depends on CPU_SUP_AMD && PCI
2099 source "drivers/pcmcia/Kconfig"
2101 source "drivers/pci/hotplug/Kconfig"
2104 bool "RapidIO support"
2108 If you say Y here, the kernel will include drivers and
2109 infrastructure code to support RapidIO interconnect devices.
2111 source "drivers/rapidio/Kconfig"
2116 menu "Executable file formats / Emulations"
2118 source "fs/Kconfig.binfmt"
2120 config IA32_EMULATION
2121 bool "IA32 Emulation"
2123 select COMPAT_BINFMT_ELF
2125 Include code to run 32-bit programs under a 64-bit kernel. You should
2126 likely turn this on, unless you're 100% sure that you don't have any
2127 32-bit programs left.
2130 tristate "IA32 a.out support"
2131 depends on IA32_EMULATION
2133 Support old a.out binaries in the 32bit emulation.
2137 depends on IA32_EMULATION
2139 config COMPAT_FOR_U64_ALIGNMENT
2143 config SYSVIPC_COMPAT
2145 depends on COMPAT && SYSVIPC
2149 depends on COMPAT && KEYS
2155 config HAVE_ATOMIC_IOMAP
2159 config HAVE_TEXT_POKE_SMP
2161 select STOP_MACHINE if SMP
2163 source "net/Kconfig"
2165 source "drivers/Kconfig"
2167 source "drivers/firmware/Kconfig"
2171 source "arch/x86/Kconfig.debug"
2173 source "security/Kconfig"
2175 source "crypto/Kconfig"
2177 source "arch/x86/kvm/Kconfig"
2179 source "lib/Kconfig"