2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PERF_EVENTS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
35 select HAVE_FTRACE_MCOUNT_RECORD
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
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
56 select HAVE_MIXED_BREAKPOINTS_REGS
58 select HAVE_PERF_EVENTS_NMI
60 select HAVE_ARCH_KMEMCHECK
61 select HAVE_USER_RETURN_NOTIFIER
63 config INSTRUCTION_DECODER
64 def_bool (KPROBES || PERF_EVENTS)
68 default "elf32-i386" if X86_32
69 default "elf64-x86-64" if X86_64
73 default "arch/x86/configs/i386_defconfig" if X86_32
74 default "arch/x86/configs/x86_64_defconfig" if X86_64
76 config GENERIC_CMOS_UPDATE
79 config CLOCKSOURCE_WATCHDOG
82 config GENERIC_CLOCKEVENTS
85 config GENERIC_CLOCKEVENTS_BROADCAST
87 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
89 config LOCKDEP_SUPPORT
92 config STACKTRACE_SUPPORT
95 config HAVE_LATENCYTOP_SUPPORT
107 config NEED_DMA_MAP_STATE
108 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
110 config NEED_SG_DMA_LENGTH
113 config GENERIC_ISA_DMA
122 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
124 config GENERIC_BUG_RELATIVE_POINTERS
127 config GENERIC_HWEIGHT
133 config ARCH_MAY_HAVE_PC_FDC
136 config RWSEM_GENERIC_SPINLOCK
139 config RWSEM_XCHGADD_ALGORITHM
142 config ARCH_HAS_CPU_IDLE_WAIT
145 config GENERIC_CALIBRATE_DELAY
148 config GENERIC_TIME_VSYSCALL
152 config ARCH_HAS_CPU_RELAX
155 config ARCH_HAS_DEFAULT_IDLE
158 config ARCH_HAS_CACHE_LINE_SIZE
161 config HAVE_SETUP_PER_CPU_AREA
164 config NEED_PER_CPU_EMBED_FIRST_CHUNK
167 config NEED_PER_CPU_PAGE_FIRST_CHUNK
170 config HAVE_CPUMASK_OF_CPU_MAP
173 config ARCH_HIBERNATION_POSSIBLE
176 config ARCH_SUSPEND_POSSIBLE
183 config ARCH_POPULATES_NODE_MAP
190 config ARCH_SUPPORTS_OPTIMIZED_INLINING
193 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
196 config HAVE_EARLY_RES
199 config HAVE_INTEL_TXT
201 depends on EXPERIMENTAL && DMAR && ACPI
203 # Use the generic interrupt handling code in kernel/irq/:
204 config GENERIC_HARDIRQS
207 config GENERIC_HARDIRQS_NO__DO_IRQ
210 config GENERIC_IRQ_PROBE
213 config GENERIC_PENDING_IRQ
215 depends on GENERIC_HARDIRQS && SMP
217 config USE_GENERIC_SMP_HELPERS
223 depends on X86_32 && SMP
227 depends on X86_64 && SMP
233 config X86_TRAMPOLINE
235 depends on SMP || (64BIT && ACPI_SLEEP)
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
241 config ARCH_HWEIGHT_CFLAGS
243 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
244 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 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 "Support sparse irq numbering"
296 depends on PCI_MSI || HT_IRQ
298 This enables support for sparse irqs. This is useful for distro
299 kernels that want to define a high CONFIG_NR_CPUS value but still
300 want to have low kernel memory footprint on smaller machines.
302 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
303 out the irq_desc[] array in a more NUMA-friendly way. )
305 If you don't know what to do here, say N.
309 depends on SPARSE_IRQ && NUMA
312 bool "Enable MPS table" if ACPI
314 depends on X86_LOCAL_APIC
316 For old smp systems that do not have proper acpi support. Newer systems
317 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
320 bool "Support for big SMP systems with more than 8 CPUs"
321 depends on X86_32 && SMP
323 This option is needed for the systems that have more than 8 CPUs
326 config X86_EXTENDED_PLATFORM
327 bool "Support for extended (non-PC) x86 platforms"
330 If you disable this option then the kernel will only support
331 standard PC platforms. (which covers the vast majority of
334 If you enable this option then you'll be able to select support
335 for the following (non-PC) 32 bit x86 platforms:
339 SGI 320/540 (Visual Workstation)
340 Summit/EXA (IBM x440)
341 Unisys ES7000 IA32 series
342 Moorestown MID devices
344 If you have one of these systems, or if you want to build a
345 generic distribution kernel, say Y here - otherwise say N.
349 config X86_EXTENDED_PLATFORM
350 bool "Support for extended (non-PC) x86 platforms"
353 If you disable this option then the kernel will only support
354 standard PC platforms. (which covers the vast majority of
357 If you enable this option then you'll be able to select support
358 for the following (non-PC) 64 bit x86 platforms:
362 If you have one of these systems, or if you want to build a
363 generic distribution kernel, say Y here - otherwise say N.
365 # This is an alphabetically sorted list of 64 bit extended platforms
366 # Please maintain the alphabetic order if and when there are additions
371 depends on X86_64 && PCI
372 depends on X86_EXTENDED_PLATFORM
374 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
375 supposed to run on these EM64T-based machines. Only choose this option
376 if you have one of these machines.
379 bool "SGI Ultraviolet"
381 depends on X86_EXTENDED_PLATFORM
383 depends on X86_X2APIC
385 This option is needed in order to support SGI Ultraviolet systems.
386 If you don't have one of these, you should say N here.
388 # Following is an alphabetically sorted list of 32 bit extended platforms
389 # Please maintain the alphabetic order if and when there are additions
394 depends on X86_EXTENDED_PLATFORM
396 Select this for an AMD Elan processor.
398 Do not use this option for K6/Athlon/Opteron processors!
400 If unsure, choose "PC-compatible" instead.
403 bool "Moorestown MID platform"
407 depends on X86_EXTENDED_PLATFORM
408 depends on X86_IO_APIC
411 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
412 Internet Device(MID) platform. Moorestown consists of two chips:
413 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
414 Unlike standard x86 PCs, Moorestown does not have many legacy devices
415 nor standard legacy replacement devices/features. e.g. Moorestown does
416 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
419 bool "RDC R-321x SoC"
421 depends on X86_EXTENDED_PLATFORM
423 select X86_REBOOTFIXUPS
425 This option is needed for RDC R-321x system-on-chip, also known
427 If you don't have one of these chips, you should say N here.
429 config X86_32_NON_STANDARD
430 bool "Support non-standard 32-bit SMP architectures"
431 depends on X86_32 && SMP
432 depends on X86_EXTENDED_PLATFORM
434 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
435 subarchitectures. It is intended for a generic binary kernel.
436 if you select them all, kernel will probe it one by one. and will
439 # Alphabetically sorted list of Non standard 32 bit platforms
442 bool "NUMAQ (IBM/Sequent)"
443 depends on X86_32_NON_STANDARD
448 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
449 NUMA multiquad box. This changes the way that processors are
450 bootstrapped, and uses Clustered Logical APIC addressing mode instead
451 of Flat Logical. You will need a new lynxer.elf file to flash your
452 firmware with - send email to <Martin.Bligh@us.ibm.com>.
454 config X86_SUPPORTS_MEMORY_FAILURE
456 # MCE code calls memory_failure():
458 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
459 depends on !X86_NUMAQ
460 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
461 depends on X86_64 || !SPARSEMEM
462 select ARCH_SUPPORTS_MEMORY_FAILURE
465 bool "SGI 320/540 (Visual Workstation)"
466 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
467 depends on X86_32_NON_STANDARD
469 The SGI Visual Workstation series is an IA32-based workstation
470 based on SGI systems chips with some legacy PC hardware attached.
472 Say Y here to create a kernel to run on the SGI 320 or 540.
474 A kernel compiled for the Visual Workstation will run on general
475 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
478 bool "Summit/EXA (IBM x440)"
479 depends on X86_32_NON_STANDARD
481 This option is needed for IBM systems that use the Summit/EXA chipset.
482 In particular, it is needed for the x440.
485 bool "Unisys ES7000 IA32 series"
486 depends on X86_32_NON_STANDARD && X86_BIGSMP
488 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
489 supposed to run on an IA32-based Unisys ES7000 system.
491 config SCHED_OMIT_FRAME_POINTER
493 prompt "Single-depth WCHAN output"
496 Calculate simpler /proc/<PID>/wchan values. If this option
497 is disabled then wchan values will recurse back to the
498 caller function. This provides more accurate wchan values,
499 at the expense of slightly more scheduling overhead.
501 If in doubt, say "Y".
503 menuconfig PARAVIRT_GUEST
504 bool "Paravirtualized guest support"
506 Say Y here to get to see options related to running Linux under
507 various hypervisors. This option alone does not add any kernel code.
509 If you say N, all options in this submenu will be skipped and disabled.
513 source "arch/x86/xen/Kconfig"
516 bool "VMI Guest support (DEPRECATED)"
520 VMI provides a paravirtualized interface to the VMware ESX server
521 (it could be used by other hypervisors in theory too, but is not
522 at the moment), by linking the kernel to a GPL-ed ROM module
523 provided by the hypervisor.
525 As of September 2009, VMware has started a phased retirement
526 of this feature from VMware's products. Please see
527 feature-removal-schedule.txt for details. If you are
528 planning to enable this option, please note that you cannot
529 live migrate a VMI enabled VM to a future VMware product,
530 which doesn't support VMI. So if you expect your kernel to
531 seamlessly migrate to newer VMware products, keep this
535 bool "KVM paravirtualized clock"
537 select PARAVIRT_CLOCK
539 Turning on this option will allow you to run a paravirtualized clock
540 when running over the KVM hypervisor. Instead of relying on a PIT
541 (or probably other) emulation by the underlying device model, the host
542 provides the guest with timing infrastructure such as time of day, and
546 bool "KVM Guest support"
549 This option enables various optimizations for running under the KVM
552 source "arch/x86/lguest/Kconfig"
555 bool "Enable paravirtualization code"
557 This changes the kernel so it can modify itself when it is run
558 under a hypervisor, potentially improving performance significantly
559 over full virtualization. However, when run without a hypervisor
560 the kernel is theoretically slower and slightly larger.
562 config PARAVIRT_SPINLOCKS
563 bool "Paravirtualization layer for spinlocks"
564 depends on PARAVIRT && SMP && EXPERIMENTAL
566 Paravirtualized spinlocks allow a pvops backend to replace the
567 spinlock implementation with something virtualization-friendly
568 (for example, block the virtual CPU rather than spinning).
570 Unfortunately the downside is an up to 5% performance hit on
571 native kernels, with various workloads.
573 If you are unsure how to answer this question, answer N.
575 config PARAVIRT_CLOCK
580 config PARAVIRT_DEBUG
581 bool "paravirt-ops debugging"
582 depends on PARAVIRT && DEBUG_KERNEL
584 Enable to debug paravirt_ops internals. Specifically, BUG if
585 a paravirt_op is missing when it is called.
589 bool "Disable Bootmem code"
591 Use early_res directly instead of bootmem before slab is ready.
592 - allocator (buddy) [generic]
593 - early allocator (bootmem) [generic]
594 - very early allocator (reserve_early*()) [x86]
595 - very very early allocator (early brk model) [x86]
596 So reduce one layer between early allocator to final allocator
602 This option adds a kernel parameter 'memtest', which allows memtest
604 memtest=0, mean disabled; -- default
605 memtest=1, mean do 1 test pattern;
607 memtest=4, mean do 4 test patterns.
608 If you are unsure how to answer this question, answer N.
610 config X86_SUMMIT_NUMA
612 depends on X86_32 && NUMA && X86_32_NON_STANDARD
614 config X86_CYCLONE_TIMER
616 depends on X86_32_NON_STANDARD
618 source "arch/x86/Kconfig.cpu"
622 prompt "HPET Timer Support" if X86_32
624 Use the IA-PC HPET (High Precision Event Timer) to manage
625 time in preference to the PIT and RTC, if a HPET is
627 HPET is the next generation timer replacing legacy 8254s.
628 The HPET 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. You can find the HPET spec at
631 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
633 You can safely choose Y here. However, HPET will only be
634 activated if the platform and the BIOS support this feature.
635 Otherwise the 8254 will be used for timing services.
637 Choose N to continue using the legacy 8254 timer.
639 config HPET_EMULATE_RTC
641 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
645 prompt "Langwell APB Timer Support" if X86_MRST
647 APB timer is the replacement for 8254, HPET on X86 MID platforms.
648 The APBT provides a stable time base on SMP
649 systems, unlike the TSC, but it is more expensive to access,
650 as it is off-chip. APB timers are always running regardless of CPU
651 C states, they are used as per CPU clockevent device when possible.
653 # Mark as embedded because too many people got it wrong.
654 # The code disables itself when not needed.
657 bool "Enable DMI scanning" if EMBEDDED
659 Enabled scanning of DMI to identify machine quirks. Say Y
660 here unless you have verified that your setup is not
661 affected by entries in the DMI blacklist. Required by PNP
665 bool "GART IOMMU support" if EMBEDDED
668 depends on X86_64 && PCI && K8_NB
670 Support for full DMA access of devices with 32bit memory access only
671 on systems with more than 3GB. This is usually needed for USB,
672 sound, many IDE/SATA chipsets and some other devices.
673 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
674 based hardware IOMMU and a software bounce buffer based IOMMU used
675 on Intel systems and as fallback.
676 The code is only active when needed (enough memory and limited
677 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
681 bool "IBM Calgary IOMMU support"
683 depends on X86_64 && PCI && EXPERIMENTAL
685 Support for hardware IOMMUs in IBM's xSeries x366 and x460
686 systems. Needed to run systems with more than 3GB of memory
687 properly with 32-bit PCI devices that do not support DAC
688 (Double Address Cycle). Calgary also supports bus level
689 isolation, where all DMAs pass through the IOMMU. This
690 prevents them from going anywhere except their intended
691 destination. This catches hard-to-find kernel bugs and
692 mis-behaving drivers and devices that do not use the DMA-API
693 properly to set up their DMA buffers. The IOMMU can be
694 turned off at boot time with the iommu=off parameter.
695 Normally the kernel will make the right choice by itself.
698 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
700 prompt "Should Calgary be enabled by default?"
701 depends on CALGARY_IOMMU
703 Should Calgary be enabled by default? if you choose 'y', Calgary
704 will be used (if it exists). If you choose 'n', Calgary will not be
705 used even if it exists. If you choose 'n' and would like to use
706 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
710 bool "AMD IOMMU support"
713 depends on X86_64 && PCI && ACPI
715 With this option you can enable support for AMD IOMMU hardware in
716 your system. An IOMMU is a hardware component which provides
717 remapping of DMA memory accesses from devices. With an AMD IOMMU you
718 can isolate the the DMA memory of different devices and protect the
719 system from misbehaving device drivers or hardware.
721 You can find out if your system has an AMD IOMMU if you look into
722 your BIOS for an option to enable it or if you have an IVRS ACPI
725 config AMD_IOMMU_STATS
726 bool "Export AMD IOMMU statistics to debugfs"
730 This option enables code in the AMD IOMMU driver to collect various
731 statistics about whats happening in the driver and exports that
732 information to userspace via debugfs.
735 # need this always selected by IOMMU for the VIA workaround
739 Support for software bounce buffers used on x86-64 systems
740 which don't have a hardware IOMMU (e.g. the current generation
741 of Intel's x86-64 CPUs). Using this PCI devices which can only
742 access 32-bits of memory can be used on systems with more than
743 3 GB of memory. If unsure, say Y.
746 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
749 def_bool (AMD_IOMMU || DMAR)
752 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
753 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
754 select CPUMASK_OFFSTACK
756 Configure maximum number of CPUS and NUMA Nodes for this architecture.
760 int "Maximum number of CPUs" if SMP && !MAXSMP
761 range 2 8 if SMP && X86_32 && !X86_BIGSMP
762 range 2 512 if SMP && !MAXSMP
764 default "4096" if MAXSMP
765 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
768 This allows you to specify the maximum number of CPUs which this
769 kernel will support. The maximum supported value is 512 and the
770 minimum value which makes sense is 2.
772 This is purely to save memory - each supported CPU adds
773 approximately eight kilobytes to the kernel image.
776 bool "SMT (Hyperthreading) scheduler support"
779 SMT scheduler support improves the CPU scheduler's decision making
780 when dealing with Intel Pentium 4 chips with HyperThreading at a
781 cost of slightly increased overhead in some places. If unsure say
786 prompt "Multi-core scheduler support"
789 Multi-core scheduler support improves the CPU scheduler's decision
790 making when dealing with multi-core CPU chips at a cost of slightly
791 increased overhead in some places. If unsure say N here.
793 source "kernel/Kconfig.preempt"
796 bool "Local APIC support on uniprocessors"
797 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
799 A local APIC (Advanced Programmable Interrupt Controller) is an
800 integrated interrupt controller in the CPU. If you have a single-CPU
801 system which has a processor with a local APIC, you can say Y here to
802 enable and use it. If you say Y here even though your machine doesn't
803 have a local APIC, then the kernel will still run with no slowdown at
804 all. The local APIC supports CPU-generated self-interrupts (timer,
805 performance counters), and the NMI watchdog which detects hard
809 bool "IO-APIC support on uniprocessors"
810 depends on X86_UP_APIC
812 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
813 SMP-capable replacement for PC-style interrupt controllers. Most
814 SMP systems and many recent uniprocessor systems have one.
816 If you have a single-CPU system with an IO-APIC, you can say Y here
817 to use it. If you say Y here even though your machine doesn't have
818 an IO-APIC, then the kernel will still run with no slowdown at all.
820 config X86_LOCAL_APIC
822 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
826 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
828 config X86_VISWS_APIC
830 depends on X86_32 && X86_VISWS
832 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
833 bool "Reroute for broken boot IRQs"
834 depends on X86_IO_APIC
836 This option enables a workaround that fixes a source of
837 spurious interrupts. This is recommended when threaded
838 interrupt handling is used on systems where the generation of
839 superfluous "boot interrupts" cannot be disabled.
841 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
842 entry in the chipset's IO-APIC is masked (as, e.g. the RT
843 kernel does during interrupt handling). On chipsets where this
844 boot IRQ generation cannot be disabled, this workaround keeps
845 the original IRQ line masked so that only the equivalent "boot
846 IRQ" is delivered to the CPUs. The workaround also tells the
847 kernel to set up the IRQ handler on the boot IRQ line. In this
848 way only one interrupt is delivered to the kernel. Otherwise
849 the spurious second interrupt may cause the kernel to bring
850 down (vital) interrupt lines.
852 Only affects "broken" chipsets. Interrupt sharing may be
853 increased on these systems.
856 bool "Machine Check / overheating reporting"
858 Machine Check support allows the processor to notify the
859 kernel if it detects a problem (e.g. overheating, data corruption).
860 The action the kernel takes depends on the severity of the problem,
861 ranging from warning messages to halting the machine.
865 prompt "Intel MCE features"
866 depends on X86_MCE && X86_LOCAL_APIC
868 Additional support for intel specific MCE features such as
873 prompt "AMD MCE features"
874 depends on X86_MCE && X86_LOCAL_APIC
876 Additional support for AMD specific MCE features such as
877 the DRAM Error Threshold.
879 config X86_ANCIENT_MCE
880 bool "Support for old Pentium 5 / WinChip machine checks"
881 depends on X86_32 && X86_MCE
883 Include support for machine check handling on old Pentium 5 or WinChip
884 systems. These typically need to be enabled explicitely on the command
887 config X86_MCE_THRESHOLD
888 depends on X86_MCE_AMD || X86_MCE_INTEL
891 config X86_MCE_INJECT
893 tristate "Machine check injector support"
895 Provide support for injecting machine checks for testing purposes.
896 If you don't know what a machine check is and you don't do kernel
897 QA it is safe to say n.
899 config X86_THERMAL_VECTOR
901 depends on X86_MCE_INTEL
904 bool "Enable VM86 support" if EMBEDDED
908 This option is required by programs like DOSEMU to run 16-bit legacy
909 code on X86 processors. It also may be needed by software like
910 XFree86 to initialize some video cards via BIOS. Disabling this
911 option saves about 6k.
914 tristate "Toshiba Laptop support"
917 This adds a driver to safely access the System Management Mode of
918 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
919 not work on models with a Phoenix BIOS. The System Management Mode
920 is used to set the BIOS and power saving options on Toshiba portables.
922 For information on utilities to make use of this driver see the
923 Toshiba Linux utilities web site at:
924 <http://www.buzzard.org.uk/toshiba/>.
926 Say Y if you intend to run this kernel on a Toshiba portable.
930 tristate "Dell laptop support"
932 This adds a driver to safely access the System Management Mode
933 of the CPU on the Dell Inspiron 8000. The System Management Mode
934 is used to read cpu temperature and cooling fan status and to
935 control the fans on the I8K portables.
937 This driver has been tested only on the Inspiron 8000 but it may
938 also work with other Dell laptops. You can force loading on other
939 models by passing the parameter `force=1' to the module. Use at
942 For information on utilities to make use of this driver see the
943 I8K Linux utilities web site at:
944 <http://people.debian.org/~dz/i8k/>
946 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
949 config X86_REBOOTFIXUPS
950 bool "Enable X86 board specific fixups for reboot"
953 This enables chipset and/or board specific fixups to be done
954 in order to get reboot to work correctly. This is only needed on
955 some combinations of hardware and BIOS. The symptom, for which
956 this config is intended, is when reboot ends with a stalled/hung
959 Currently, the only fixup is for the Geode machines using
960 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
962 Say Y if you want to enable the fixup. Currently, it's safe to
963 enable this option even if you don't need it.
967 tristate "/dev/cpu/microcode - microcode support"
970 If you say Y here, you will be able to update the microcode on
971 certain Intel and AMD processors. The Intel support is for the
972 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
973 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
974 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
975 You will obviously need the actual microcode binary data itself
976 which is not shipped with the Linux kernel.
978 This option selects the general module only, you need to select
979 at least one vendor specific module as well.
981 To compile this driver as a module, choose M here: the
982 module will be called microcode.
984 config MICROCODE_INTEL
985 bool "Intel microcode patch loading support"
990 This options enables microcode patch loading support for Intel
993 For latest news and information on obtaining all the required
994 Intel ingredients for this driver, check:
995 <http://www.urbanmyth.org/microcode/>.
998 bool "AMD microcode patch loading support"
1002 If you select this option, microcode patch loading support for AMD
1003 processors will be enabled.
1005 config MICROCODE_OLD_INTERFACE
1007 depends on MICROCODE
1010 tristate "/dev/cpu/*/msr - Model-specific register support"
1012 This device gives privileged processes access to the x86
1013 Model-Specific Registers (MSRs). It is a character device with
1014 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1015 MSR accesses are directed to a specific CPU on multi-processor
1019 tristate "/dev/cpu/*/cpuid - CPU information support"
1021 This device gives processes access to the x86 CPUID instruction to
1022 be executed on a specific processor. It is a character device
1023 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1027 prompt "High Memory Support"
1028 default HIGHMEM64G if X86_NUMAQ
1034 depends on !X86_NUMAQ
1036 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1037 However, the address space of 32-bit x86 processors is only 4
1038 Gigabytes large. That means that, if you have a large amount of
1039 physical memory, not all of it can be "permanently mapped" by the
1040 kernel. The physical memory that's not permanently mapped is called
1043 If you are compiling a kernel which will never run on a machine with
1044 more than 1 Gigabyte total physical RAM, answer "off" here (default
1045 choice and suitable for most users). This will result in a "3GB/1GB"
1046 split: 3GB are mapped so that each process sees a 3GB virtual memory
1047 space and the remaining part of the 4GB virtual memory space is used
1048 by the kernel to permanently map as much physical memory as
1051 If the machine has between 1 and 4 Gigabytes physical RAM, then
1054 If more than 4 Gigabytes is used then answer "64GB" here. This
1055 selection turns Intel PAE (Physical Address Extension) mode on.
1056 PAE implements 3-level paging on IA32 processors. PAE is fully
1057 supported by Linux, PAE mode is implemented on all recent Intel
1058 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1059 then the kernel will not boot on CPUs that don't support PAE!
1061 The actual amount of total physical memory will either be
1062 auto detected or can be forced by using a kernel command line option
1063 such as "mem=256M". (Try "man bootparam" or see the documentation of
1064 your boot loader (lilo or loadlin) about how to pass options to the
1065 kernel at boot time.)
1067 If unsure, say "off".
1071 depends on !X86_NUMAQ
1073 Select this if you have a 32-bit processor and between 1 and 4
1074 gigabytes of physical RAM.
1078 depends on !M386 && !M486
1081 Select this if you have a 32-bit processor and more than 4
1082 gigabytes of physical RAM.
1087 depends on EXPERIMENTAL
1088 prompt "Memory split" if EMBEDDED
1092 Select the desired split between kernel and user memory.
1094 If the address range available to the kernel is less than the
1095 physical memory installed, the remaining memory will be available
1096 as "high memory". Accessing high memory is a little more costly
1097 than low memory, as it needs to be mapped into the kernel first.
1098 Note that increasing the kernel address space limits the range
1099 available to user programs, making the address space there
1100 tighter. Selecting anything other than the default 3G/1G split
1101 will also likely make your kernel incompatible with binary-only
1104 If you are not absolutely sure what you are doing, leave this
1108 bool "3G/1G user/kernel split"
1109 config VMSPLIT_3G_OPT
1111 bool "3G/1G user/kernel split (for full 1G low memory)"
1113 bool "2G/2G user/kernel split"
1114 config VMSPLIT_2G_OPT
1116 bool "2G/2G user/kernel split (for full 2G low memory)"
1118 bool "1G/3G user/kernel split"
1123 default 0xB0000000 if VMSPLIT_3G_OPT
1124 default 0x80000000 if VMSPLIT_2G
1125 default 0x78000000 if VMSPLIT_2G_OPT
1126 default 0x40000000 if VMSPLIT_1G
1132 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1135 bool "PAE (Physical Address Extension) Support"
1136 depends on X86_32 && !HIGHMEM4G
1138 PAE is required for NX support, and furthermore enables
1139 larger swapspace support for non-overcommit purposes. It
1140 has the cost of more pagetable lookup overhead, and also
1141 consumes more pagetable space per process.
1143 config ARCH_PHYS_ADDR_T_64BIT
1144 def_bool X86_64 || X86_PAE
1146 config DIRECT_GBPAGES
1147 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1151 Allow the kernel linear mapping to use 1GB pages on CPUs that
1152 support it. This can improve the kernel's performance a tiny bit by
1153 reducing TLB pressure. If in doubt, say "Y".
1155 # Common NUMA Features
1157 bool "Numa Memory Allocation and Scheduler Support"
1159 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1160 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1162 Enable NUMA (Non Uniform Memory Access) support.
1164 The kernel will try to allocate memory used by a CPU on the
1165 local memory controller of the CPU and add some more
1166 NUMA awareness to the kernel.
1168 For 64-bit this is recommended if the system is Intel Core i7
1169 (or later), AMD Opteron, or EM64T NUMA.
1171 For 32-bit this is only needed on (rare) 32-bit-only platforms
1172 that support NUMA topologies, such as NUMAQ / Summit, or if you
1173 boot a 32-bit kernel on a 64-bit NUMA platform.
1175 Otherwise, you should say N.
1177 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1178 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1182 prompt "Old style AMD Opteron NUMA detection"
1183 depends on X86_64 && NUMA && PCI
1185 Enable K8 NUMA node topology detection. You should say Y here if
1186 you have a multi processor AMD K8 system. This uses an old
1187 method to read the NUMA configuration directly from the builtin
1188 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1189 instead, which also takes priority if both are compiled in.
1191 config X86_64_ACPI_NUMA
1193 prompt "ACPI NUMA detection"
1194 depends on X86_64 && NUMA && ACPI && PCI
1197 Enable ACPI SRAT based node topology detection.
1199 # Some NUMA nodes have memory ranges that span
1200 # other nodes. Even though a pfn is valid and
1201 # between a node's start and end pfns, it may not
1202 # reside on that node. See memmap_init_zone()
1204 config NODES_SPAN_OTHER_NODES
1206 depends on X86_64_ACPI_NUMA
1209 bool "NUMA emulation"
1210 depends on X86_64 && NUMA
1212 Enable NUMA emulation. A flat machine will be split
1213 into virtual nodes when booted with "numa=fake=N", where N is the
1214 number of nodes. This is only useful for debugging.
1217 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1219 default "10" if MAXSMP
1220 default "6" if X86_64
1221 default "4" if X86_NUMAQ
1223 depends on NEED_MULTIPLE_NODES
1225 Specify the maximum number of NUMA Nodes available on the target
1226 system. Increases memory reserved to accommodate various tables.
1228 config HAVE_ARCH_BOOTMEM
1230 depends on X86_32 && NUMA
1232 config ARCH_HAVE_MEMORY_PRESENT
1234 depends on X86_32 && DISCONTIGMEM
1236 config NEED_NODE_MEMMAP_SIZE
1238 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1240 config HAVE_ARCH_ALLOC_REMAP
1242 depends on X86_32 && NUMA
1244 config ARCH_FLATMEM_ENABLE
1246 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1248 config ARCH_DISCONTIGMEM_ENABLE
1250 depends on NUMA && X86_32
1252 config ARCH_DISCONTIGMEM_DEFAULT
1254 depends on NUMA && X86_32
1256 config ARCH_PROC_KCORE_TEXT
1258 depends on X86_64 && PROC_KCORE
1260 config ARCH_SPARSEMEM_DEFAULT
1264 config ARCH_SPARSEMEM_ENABLE
1266 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1267 select SPARSEMEM_STATIC if X86_32
1268 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1270 config ARCH_SELECT_MEMORY_MODEL
1272 depends on ARCH_SPARSEMEM_ENABLE
1274 config ARCH_MEMORY_PROBE
1276 depends on MEMORY_HOTPLUG
1278 config ILLEGAL_POINTER_VALUE
1281 default 0xdead000000000000 if X86_64
1286 bool "Allocate 3rd-level pagetables from highmem"
1289 The VM uses one page table entry for each page of physical memory.
1290 For systems with a lot of RAM, this can be wasteful of precious
1291 low memory. Setting this option will put user-space page table
1292 entries in high memory.
1294 config X86_CHECK_BIOS_CORRUPTION
1295 bool "Check for low memory corruption"
1297 Periodically check for memory corruption in low memory, which
1298 is suspected to be caused by BIOS. Even when enabled in the
1299 configuration, it is disabled at runtime. Enable it by
1300 setting "memory_corruption_check=1" on the kernel command
1301 line. By default it scans the low 64k of memory every 60
1302 seconds; see the memory_corruption_check_size and
1303 memory_corruption_check_period parameters in
1304 Documentation/kernel-parameters.txt to adjust this.
1306 When enabled with the default parameters, this option has
1307 almost no overhead, as it reserves a relatively small amount
1308 of memory and scans it infrequently. It both detects corruption
1309 and prevents it from affecting the running system.
1311 It is, however, intended as a diagnostic tool; if repeatable
1312 BIOS-originated corruption always affects the same memory,
1313 you can use memmap= to prevent the kernel from using that
1316 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1317 bool "Set the default setting of memory_corruption_check"
1318 depends on X86_CHECK_BIOS_CORRUPTION
1321 Set whether the default state of memory_corruption_check is
1324 config X86_RESERVE_LOW_64K
1325 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1328 Reserve the first 64K of physical RAM on BIOSes that are known
1329 to potentially corrupt that memory range. A numbers of BIOSes are
1330 known to utilize this area during suspend/resume, so it must not
1331 be used by the kernel.
1333 Set this to N if you are absolutely sure that you trust the BIOS
1334 to get all its memory reservations and usages right.
1336 If you have doubts about the BIOS (e.g. suspend/resume does not
1337 work or there's kernel crashes after certain hardware hotplug
1338 events) and it's not AMI or Phoenix, then you might want to enable
1339 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1340 corruption patterns.
1344 config MATH_EMULATION
1346 prompt "Math emulation" if X86_32
1348 Linux can emulate a math coprocessor (used for floating point
1349 operations) if you don't have one. 486DX and Pentium processors have
1350 a math coprocessor built in, 486SX and 386 do not, unless you added
1351 a 487DX or 387, respectively. (The messages during boot time can
1352 give you some hints here ["man dmesg"].) Everyone needs either a
1353 coprocessor or this emulation.
1355 If you don't have a math coprocessor, you need to say Y here; if you
1356 say Y here even though you have a coprocessor, the coprocessor will
1357 be used nevertheless. (This behavior can be changed with the kernel
1358 command line option "no387", which comes handy if your coprocessor
1359 is broken. Try "man bootparam" or see the documentation of your boot
1360 loader (lilo or loadlin) about how to pass options to the kernel at
1361 boot time.) This means that it is a good idea to say Y here if you
1362 intend to use this kernel on different machines.
1364 More information about the internals of the Linux math coprocessor
1365 emulation can be found in <file:arch/x86/math-emu/README>.
1367 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1368 kernel, it won't hurt.
1372 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1374 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1375 the Memory Type Range Registers (MTRRs) may be used to control
1376 processor access to memory ranges. This is most useful if you have
1377 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1378 allows bus write transfers to be combined into a larger transfer
1379 before bursting over the PCI/AGP bus. This can increase performance
1380 of image write operations 2.5 times or more. Saying Y here creates a
1381 /proc/mtrr file which may be used to manipulate your processor's
1382 MTRRs. Typically the X server should use this.
1384 This code has a reasonably generic interface so that similar
1385 control registers on other processors can be easily supported
1388 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1389 Registers (ARRs) which provide a similar functionality to MTRRs. For
1390 these, the ARRs are used to emulate the MTRRs.
1391 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1392 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1393 write-combining. All of these processors are supported by this code
1394 and it makes sense to say Y here if you have one of them.
1396 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1397 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1398 can lead to all sorts of problems, so it's good to say Y here.
1400 You can safely say Y even if your machine doesn't have MTRRs, you'll
1401 just add about 9 KB to your kernel.
1403 See <file:Documentation/x86/mtrr.txt> for more information.
1405 config MTRR_SANITIZER
1407 prompt "MTRR cleanup support"
1410 Convert MTRR layout from continuous to discrete, so X drivers can
1411 add writeback entries.
1413 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1414 The largest mtrr entry size for a continuous block can be set with
1419 config MTRR_SANITIZER_ENABLE_DEFAULT
1420 int "MTRR cleanup enable value (0-1)"
1423 depends on MTRR_SANITIZER
1425 Enable mtrr cleanup default value
1427 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1428 int "MTRR cleanup spare reg num (0-7)"
1431 depends on MTRR_SANITIZER
1433 mtrr cleanup spare entries default, it can be changed via
1434 mtrr_spare_reg_nr=N on the kernel command line.
1438 prompt "x86 PAT support" if EMBEDDED
1441 Use PAT attributes to setup page level cache control.
1443 PATs are the modern equivalents of MTRRs and are much more
1444 flexible than MTRRs.
1446 Say N here if you see bootup problems (boot crash, boot hang,
1447 spontaneous reboots) or a non-working video driver.
1451 config ARCH_USES_PG_UNCACHED
1456 bool "EFI runtime service support"
1459 This enables the kernel to use EFI runtime services that are
1460 available (such as the EFI variable services).
1462 This option is only useful on systems that have EFI firmware.
1463 In addition, you should use the latest ELILO loader available
1464 at <http://elilo.sourceforge.net> in order to take advantage
1465 of EFI runtime services. However, even with this option, the
1466 resultant kernel should continue to boot on existing non-EFI
1471 prompt "Enable seccomp to safely compute untrusted bytecode"
1473 This kernel feature is useful for number crunching applications
1474 that may need to compute untrusted bytecode during their
1475 execution. By using pipes or other transports made available to
1476 the process as file descriptors supporting the read/write
1477 syscalls, it's possible to isolate those applications in
1478 their own address space using seccomp. Once seccomp is
1479 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1480 and the task is only allowed to execute a few safe syscalls
1481 defined by each seccomp mode.
1483 If unsure, say Y. Only embedded should say N here.
1485 config CC_STACKPROTECTOR
1486 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1488 This option turns on the -fstack-protector GCC feature. This
1489 feature puts, at the beginning of functions, a canary value on
1490 the stack just before the return address, and validates
1491 the value just before actually returning. Stack based buffer
1492 overflows (that need to overwrite this return address) now also
1493 overwrite the canary, which gets detected and the attack is then
1494 neutralized via a kernel panic.
1496 This feature requires gcc version 4.2 or above, or a distribution
1497 gcc with the feature backported. Older versions are automatically
1498 detected and for those versions, this configuration option is
1499 ignored. (and a warning is printed during bootup)
1501 source kernel/Kconfig.hz
1504 bool "kexec system call"
1506 kexec is a system call that implements the ability to shutdown your
1507 current kernel, and to start another kernel. It is like a reboot
1508 but it is independent of the system firmware. And like a reboot
1509 you can start any kernel with it, not just Linux.
1511 The name comes from the similarity to the exec system call.
1513 It is an ongoing process to be certain the hardware in a machine
1514 is properly shutdown, so do not be surprised if this code does not
1515 initially work for you. It may help to enable device hotplugging
1516 support. As of this writing the exact hardware interface is
1517 strongly in flux, so no good recommendation can be made.
1520 bool "kernel crash dumps"
1521 depends on X86_64 || (X86_32 && HIGHMEM)
1523 Generate crash dump after being started by kexec.
1524 This should be normally only set in special crash dump kernels
1525 which are loaded in the main kernel with kexec-tools into
1526 a specially reserved region and then later executed after
1527 a crash by kdump/kexec. The crash dump kernel must be compiled
1528 to a memory address not used by the main kernel or BIOS using
1529 PHYSICAL_START, or it must be built as a relocatable image
1530 (CONFIG_RELOCATABLE=y).
1531 For more details see Documentation/kdump/kdump.txt
1534 bool "kexec jump (EXPERIMENTAL)"
1535 depends on EXPERIMENTAL
1536 depends on KEXEC && HIBERNATION
1538 Jump between original kernel and kexeced kernel and invoke
1539 code in physical address mode via KEXEC
1541 config PHYSICAL_START
1542 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1545 This gives the physical address where the kernel is loaded.
1547 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1548 bzImage will decompress itself to above physical address and
1549 run from there. Otherwise, bzImage will run from the address where
1550 it has been loaded by the boot loader and will ignore above physical
1553 In normal kdump cases one does not have to set/change this option
1554 as now bzImage can be compiled as a completely relocatable image
1555 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1556 address. This option is mainly useful for the folks who don't want
1557 to use a bzImage for capturing the crash dump and want to use a
1558 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1559 to be specifically compiled to run from a specific memory area
1560 (normally a reserved region) and this option comes handy.
1562 So if you are using bzImage for capturing the crash dump,
1563 leave the value here unchanged to 0x1000000 and set
1564 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1565 for capturing the crash dump change this value to start of
1566 the reserved region. In other words, it can be set based on
1567 the "X" value as specified in the "crashkernel=YM@XM"
1568 command line boot parameter passed to the panic-ed
1569 kernel. Please take a look at Documentation/kdump/kdump.txt
1570 for more details about crash dumps.
1572 Usage of bzImage for capturing the crash dump is recommended as
1573 one does not have to build two kernels. Same kernel can be used
1574 as production kernel and capture kernel. Above option should have
1575 gone away after relocatable bzImage support is introduced. But it
1576 is present because there are users out there who continue to use
1577 vmlinux for dump capture. This option should go away down the
1580 Don't change this unless you know what you are doing.
1583 bool "Build a relocatable kernel"
1586 This builds a kernel image that retains relocation information
1587 so it can be loaded someplace besides the default 1MB.
1588 The relocations tend to make the kernel binary about 10% larger,
1589 but are discarded at runtime.
1591 One use is for the kexec on panic case where the recovery kernel
1592 must live at a different physical address than the primary
1595 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1596 it has been loaded at and the compile time physical address
1597 (CONFIG_PHYSICAL_START) is ignored.
1599 # Relocation on x86-32 needs some additional build support
1600 config X86_NEED_RELOCS
1602 depends on X86_32 && RELOCATABLE
1604 config PHYSICAL_ALIGN
1605 hex "Alignment value to which kernel should be aligned" if X86_32
1607 range 0x2000 0x1000000
1609 This value puts the alignment restrictions on physical address
1610 where kernel is loaded and run from. Kernel is compiled for an
1611 address which meets above alignment restriction.
1613 If bootloader loads the kernel at a non-aligned address and
1614 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1615 address aligned to above value and run from there.
1617 If bootloader loads the kernel at a non-aligned address and
1618 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1619 load address and decompress itself to the address it has been
1620 compiled for and run from there. The address for which kernel is
1621 compiled already meets above alignment restrictions. Hence the
1622 end result is that kernel runs from a physical address meeting
1623 above alignment restrictions.
1625 Don't change this unless you know what you are doing.
1628 bool "Support for hot-pluggable CPUs"
1629 depends on SMP && HOTPLUG
1631 Say Y here to allow turning CPUs off and on. CPUs can be
1632 controlled through /sys/devices/system/cpu.
1633 ( Note: power management support will enable this option
1634 automatically on SMP systems. )
1635 Say N if you want to disable CPU hotplug.
1639 prompt "Compat VDSO support"
1640 depends on X86_32 || IA32_EMULATION
1642 Map the 32-bit VDSO to the predictable old-style address too.
1644 Say N here if you are running a sufficiently recent glibc
1645 version (2.3.3 or later), to remove the high-mapped
1646 VDSO mapping and to exclusively use the randomized VDSO.
1651 bool "Built-in kernel command line"
1653 Allow for specifying boot arguments to the kernel at
1654 build time. On some systems (e.g. embedded ones), it is
1655 necessary or convenient to provide some or all of the
1656 kernel boot arguments with the kernel itself (that is,
1657 to not rely on the boot loader to provide them.)
1659 To compile command line arguments into the kernel,
1660 set this option to 'Y', then fill in the
1661 the boot arguments in CONFIG_CMDLINE.
1663 Systems with fully functional boot loaders (i.e. non-embedded)
1664 should leave this option set to 'N'.
1667 string "Built-in kernel command string"
1668 depends on CMDLINE_BOOL
1671 Enter arguments here that should be compiled into the kernel
1672 image and used at boot time. If the boot loader provides a
1673 command line at boot time, it is appended to this string to
1674 form the full kernel command line, when the system boots.
1676 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1677 change this behavior.
1679 In most cases, the command line (whether built-in or provided
1680 by the boot loader) should specify the device for the root
1683 config CMDLINE_OVERRIDE
1684 bool "Built-in command line overrides boot loader arguments"
1685 depends on CMDLINE_BOOL
1687 Set this option to 'Y' to have the kernel ignore the boot loader
1688 command line, and use ONLY the built-in command line.
1690 This is used to work around broken boot loaders. This should
1691 be set to 'N' under normal conditions.
1695 config ARCH_ENABLE_MEMORY_HOTPLUG
1697 depends on X86_64 || (X86_32 && HIGHMEM)
1699 config ARCH_ENABLE_MEMORY_HOTREMOVE
1701 depends on MEMORY_HOTPLUG
1703 config HAVE_ARCH_EARLY_PFN_TO_NID
1707 config USE_PERCPU_NUMA_NODE_ID
1711 menu "Power management and ACPI options"
1713 config ARCH_HIBERNATION_HEADER
1715 depends on X86_64 && HIBERNATION
1717 source "kernel/power/Kconfig"
1719 source "drivers/acpi/Kconfig"
1721 source "drivers/sfi/Kconfig"
1725 depends on APM || APM_MODULE
1728 tristate "APM (Advanced Power Management) BIOS support"
1729 depends on X86_32 && PM_SLEEP
1731 APM is a BIOS specification for saving power using several different
1732 techniques. This is mostly useful for battery powered laptops with
1733 APM compliant BIOSes. If you say Y here, the system time will be
1734 reset after a RESUME operation, the /proc/apm device will provide
1735 battery status information, and user-space programs will receive
1736 notification of APM "events" (e.g. battery status change).
1738 If you select "Y" here, you can disable actual use of the APM
1739 BIOS by passing the "apm=off" option to the kernel at boot time.
1741 Note that the APM support is almost completely disabled for
1742 machines with more than one CPU.
1744 In order to use APM, you will need supporting software. For location
1745 and more information, read <file:Documentation/power/pm.txt> and the
1746 Battery Powered Linux mini-HOWTO, available from
1747 <http://www.tldp.org/docs.html#howto>.
1749 This driver does not spin down disk drives (see the hdparm(8)
1750 manpage ("man 8 hdparm") for that), and it doesn't turn off
1751 VESA-compliant "green" monitors.
1753 This driver does not support the TI 4000M TravelMate and the ACER
1754 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1755 desktop machines also don't have compliant BIOSes, and this driver
1756 may cause those machines to panic during the boot phase.
1758 Generally, if you don't have a battery in your machine, there isn't
1759 much point in using this driver and you should say N. If you get
1760 random kernel OOPSes or reboots that don't seem to be related to
1761 anything, try disabling/enabling this option (or disabling/enabling
1764 Some other things you should try when experiencing seemingly random,
1767 1) make sure that you have enough swap space and that it is
1769 2) pass the "no-hlt" option to the kernel
1770 3) switch on floating point emulation in the kernel and pass
1771 the "no387" option to the kernel
1772 4) pass the "floppy=nodma" option to the kernel
1773 5) pass the "mem=4M" option to the kernel (thereby disabling
1774 all but the first 4 MB of RAM)
1775 6) make sure that the CPU is not over clocked.
1776 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1777 8) disable the cache from your BIOS settings
1778 9) install a fan for the video card or exchange video RAM
1779 10) install a better fan for the CPU
1780 11) exchange RAM chips
1781 12) exchange the motherboard.
1783 To compile this driver as a module, choose M here: the
1784 module will be called apm.
1788 config APM_IGNORE_USER_SUSPEND
1789 bool "Ignore USER SUSPEND"
1791 This option will ignore USER SUSPEND requests. On machines with a
1792 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1793 series notebooks, it is necessary to say Y because of a BIOS bug.
1795 config APM_DO_ENABLE
1796 bool "Enable PM at boot time"
1798 Enable APM features at boot time. From page 36 of the APM BIOS
1799 specification: "When disabled, the APM BIOS does not automatically
1800 power manage devices, enter the Standby State, enter the Suspend
1801 State, or take power saving steps in response to CPU Idle calls."
1802 This driver will make CPU Idle calls when Linux is idle (unless this
1803 feature is turned off -- see "Do CPU IDLE calls", below). This
1804 should always save battery power, but more complicated APM features
1805 will be dependent on your BIOS implementation. You may need to turn
1806 this option off if your computer hangs at boot time when using APM
1807 support, or if it beeps continuously instead of suspending. Turn
1808 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1809 T400CDT. This is off by default since most machines do fine without
1813 bool "Make CPU Idle calls when idle"
1815 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1816 On some machines, this can activate improved power savings, such as
1817 a slowed CPU clock rate, when the machine is idle. These idle calls
1818 are made after the idle loop has run for some length of time (e.g.,
1819 333 mS). On some machines, this will cause a hang at boot time or
1820 whenever the CPU becomes idle. (On machines with more than one CPU,
1821 this option does nothing.)
1823 config APM_DISPLAY_BLANK
1824 bool "Enable console blanking using APM"
1826 Enable console blanking using the APM. Some laptops can use this to
1827 turn off the LCD backlight when the screen blanker of the Linux
1828 virtual console blanks the screen. Note that this is only used by
1829 the virtual console screen blanker, and won't turn off the backlight
1830 when using the X Window system. This also doesn't have anything to
1831 do with your VESA-compliant power-saving monitor. Further, this
1832 option doesn't work for all laptops -- it might not turn off your
1833 backlight at all, or it might print a lot of errors to the console,
1834 especially if you are using gpm.
1836 config APM_ALLOW_INTS
1837 bool "Allow interrupts during APM BIOS calls"
1839 Normally we disable external interrupts while we are making calls to
1840 the APM BIOS as a measure to lessen the effects of a badly behaving
1841 BIOS implementation. The BIOS should reenable interrupts if it
1842 needs to. Unfortunately, some BIOSes do not -- especially those in
1843 many of the newer IBM Thinkpads. If you experience hangs when you
1844 suspend, try setting this to Y. Otherwise, say N.
1848 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1850 source "drivers/cpuidle/Kconfig"
1852 source "drivers/idle/Kconfig"
1857 menu "Bus options (PCI etc.)"
1862 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1864 Find out whether you have a PCI motherboard. PCI is the name of a
1865 bus system, i.e. the way the CPU talks to the other stuff inside
1866 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1867 VESA. If you have PCI, say Y, otherwise N.
1870 prompt "PCI access mode"
1871 depends on X86_32 && PCI
1874 On PCI systems, the BIOS can be used to detect the PCI devices and
1875 determine their configuration. However, some old PCI motherboards
1876 have BIOS bugs and may crash if this is done. Also, some embedded
1877 PCI-based systems don't have any BIOS at all. Linux can also try to
1878 detect the PCI hardware directly without using the BIOS.
1880 With this option, you can specify how Linux should detect the
1881 PCI devices. If you choose "BIOS", the BIOS will be used,
1882 if you choose "Direct", the BIOS won't be used, and if you
1883 choose "MMConfig", then PCI Express MMCONFIG will be used.
1884 If you choose "Any", the kernel will try MMCONFIG, then the
1885 direct access method and falls back to the BIOS if that doesn't
1886 work. If unsure, go with the default, which is "Any".
1891 config PCI_GOMMCONFIG
1908 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1910 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1913 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1917 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1921 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1928 bool "Support mmconfig PCI config space access"
1929 depends on X86_64 && PCI && ACPI
1931 config PCI_CNB20LE_QUIRK
1932 bool "Read CNB20LE Host Bridge Windows"
1935 Read the PCI windows out of the CNB20LE host bridge. This allows
1936 PCI hotplug to work on systems with the CNB20LE chipset which do
1940 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1941 depends on PCI_MSI && ACPI && EXPERIMENTAL
1943 DMA remapping (DMAR) devices support enables independent address
1944 translations for Direct Memory Access (DMA) from devices.
1945 These DMA remapping devices are reported via ACPI tables
1946 and include PCI device scope covered by these DMA
1949 config DMAR_DEFAULT_ON
1951 prompt "Enable DMA Remapping Devices by default"
1954 Selecting this option will enable a DMAR device at boot time if
1955 one is found. If this option is not selected, DMAR support can
1956 be enabled by passing intel_iommu=on to the kernel. It is
1957 recommended you say N here while the DMAR code remains
1960 config DMAR_BROKEN_GFX_WA
1961 bool "Workaround broken graphics drivers (going away soon)"
1962 depends on DMAR && BROKEN
1964 Current Graphics drivers tend to use physical address
1965 for DMA and avoid using DMA APIs. Setting this config
1966 option permits the IOMMU driver to set a unity map for
1967 all the OS-visible memory. Hence the driver can continue
1968 to use physical addresses for DMA, at least until this
1969 option is removed in the 2.6.32 kernel.
1971 config DMAR_FLOPPY_WA
1975 Floppy disk drivers are known to bypass DMA API calls
1976 thereby failing to work when IOMMU is enabled. This
1977 workaround will setup a 1:1 mapping for the first
1978 16MiB to make floppy (an ISA device) work.
1981 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1982 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1984 Supports Interrupt remapping for IO-APIC and MSI devices.
1985 To use x2apic mode in the CPU's which support x2APIC enhancements or
1986 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1988 source "drivers/pci/pcie/Kconfig"
1990 source "drivers/pci/Kconfig"
1992 # x86_64 have no ISA slots, but do have ISA-style DMA.
2001 Find out whether you have ISA slots on your motherboard. ISA is the
2002 name of a bus system, i.e. the way the CPU talks to the other stuff
2003 inside your box. Other bus systems are PCI, EISA, MicroChannel
2004 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2005 newer boards don't support it. If you have ISA, say Y, otherwise N.
2011 The Extended Industry Standard Architecture (EISA) bus was
2012 developed as an open alternative to the IBM MicroChannel bus.
2014 The EISA bus provided some of the features of the IBM MicroChannel
2015 bus while maintaining backward compatibility with cards made for
2016 the older ISA bus. The EISA bus saw limited use between 1988 and
2017 1995 when it was made obsolete by the PCI bus.
2019 Say Y here if you are building a kernel for an EISA-based machine.
2023 source "drivers/eisa/Kconfig"
2028 MicroChannel Architecture is found in some IBM PS/2 machines and
2029 laptops. It is a bus system similar to PCI or ISA. See
2030 <file:Documentation/mca.txt> (and especially the web page given
2031 there) before attempting to build an MCA bus kernel.
2033 source "drivers/mca/Kconfig"
2036 tristate "NatSemi SCx200 support"
2038 This provides basic support for National Semiconductor's
2039 (now AMD's) Geode processors. The driver probes for the
2040 PCI-IDs of several on-chip devices, so its a good dependency
2041 for other scx200_* drivers.
2043 If compiled as a module, the driver is named scx200.
2045 config SCx200HR_TIMER
2046 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2050 This driver provides a clocksource built upon the on-chip
2051 27MHz high-resolution timer. Its also a workaround for
2052 NSC Geode SC-1100's buggy TSC, which loses time when the
2053 processor goes idle (as is done by the scheduler). The
2054 other workaround is idle=poll boot option.
2057 bool "One Laptop Per Child support"
2060 Add support for detecting the unique features of the OLPC
2063 config OLPC_OPENFIRMWARE
2064 bool "Support for OLPC's Open Firmware"
2065 depends on !X86_64 && !X86_PAE
2068 This option adds support for the implementation of Open Firmware
2069 that is used on the OLPC XO-1 Children's Machine.
2070 If unsure, say N here.
2076 depends on CPU_SUP_AMD && PCI
2078 source "drivers/pcmcia/Kconfig"
2080 source "drivers/pci/hotplug/Kconfig"
2085 menu "Executable file formats / Emulations"
2087 source "fs/Kconfig.binfmt"
2089 config IA32_EMULATION
2090 bool "IA32 Emulation"
2092 select COMPAT_BINFMT_ELF
2094 Include code to run 32-bit programs under a 64-bit kernel. You should
2095 likely turn this on, unless you're 100% sure that you don't have any
2096 32-bit programs left.
2099 tristate "IA32 a.out support"
2100 depends on IA32_EMULATION
2102 Support old a.out binaries in the 32bit emulation.
2106 depends on IA32_EMULATION
2108 config COMPAT_FOR_U64_ALIGNMENT
2112 config SYSVIPC_COMPAT
2114 depends on COMPAT && SYSVIPC
2119 config HAVE_ATOMIC_IOMAP
2123 source "net/Kconfig"
2125 source "drivers/Kconfig"
2127 source "drivers/firmware/Kconfig"
2131 source "arch/x86/Kconfig.debug"
2133 source "security/Kconfig"
2135 source "crypto/Kconfig"
2137 source "arch/x86/kvm/Kconfig"
2139 source "lib/Kconfig"