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
59 select HAVE_ARCH_KMEMCHECK
60 select HAVE_USER_RETURN_NOTIFIER
62 config INSTRUCTION_DECODER
63 def_bool (KPROBES || PERF_EVENTS)
67 default "elf32-i386" if X86_32
68 default "elf64-x86-64" if X86_64
72 default "arch/x86/configs/i386_defconfig" if X86_32
73 default "arch/x86/configs/x86_64_defconfig" if X86_64
78 config GENERIC_CMOS_UPDATE
81 config CLOCKSOURCE_WATCHDOG
84 config GENERIC_CLOCKEVENTS
87 config GENERIC_CLOCKEVENTS_BROADCAST
89 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
91 config LOCKDEP_SUPPORT
94 config STACKTRACE_SUPPORT
97 config HAVE_LATENCYTOP_SUPPORT
109 config NEED_DMA_MAP_STATE
110 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
112 config NEED_SG_DMA_LENGTH
115 config GENERIC_ISA_DMA
124 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
126 config GENERIC_BUG_RELATIVE_POINTERS
129 config GENERIC_HWEIGHT
135 config ARCH_MAY_HAVE_PC_FDC
138 config RWSEM_GENERIC_SPINLOCK
141 config RWSEM_XCHGADD_ALGORITHM
144 config ARCH_HAS_CPU_IDLE_WAIT
147 config GENERIC_CALIBRATE_DELAY
150 config GENERIC_TIME_VSYSCALL
154 config ARCH_HAS_CPU_RELAX
157 config ARCH_HAS_DEFAULT_IDLE
160 config ARCH_HAS_CACHE_LINE_SIZE
163 config HAVE_SETUP_PER_CPU_AREA
166 config NEED_PER_CPU_EMBED_FIRST_CHUNK
169 config NEED_PER_CPU_PAGE_FIRST_CHUNK
172 config HAVE_CPUMASK_OF_CPU_MAP
175 config ARCH_HIBERNATION_POSSIBLE
178 config ARCH_SUSPEND_POSSIBLE
185 config ARCH_POPULATES_NODE_MAP
192 config ARCH_SUPPORTS_OPTIMIZED_INLINING
195 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
198 config HAVE_EARLY_RES
201 config HAVE_INTEL_TXT
203 depends on EXPERIMENTAL && DMAR && ACPI
205 # Use the generic interrupt handling code in kernel/irq/:
206 config GENERIC_HARDIRQS
209 config GENERIC_HARDIRQS_NO__DO_IRQ
212 config GENERIC_IRQ_PROBE
215 config GENERIC_PENDING_IRQ
217 depends on GENERIC_HARDIRQS && SMP
219 config USE_GENERIC_SMP_HELPERS
225 depends on X86_32 && SMP
229 depends on X86_64 && SMP
235 config X86_TRAMPOLINE
237 depends on SMP || (64BIT && ACPI_SLEEP)
239 config X86_32_LAZY_GS
241 depends on X86_32 && !CC_STACKPROTECTOR
243 config ARCH_HWEIGHT_CFLAGS
245 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
246 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
250 source "init/Kconfig"
251 source "kernel/Kconfig.freezer"
253 menu "Processor type and features"
255 source "kernel/time/Kconfig"
258 bool "Symmetric multi-processing support"
260 This enables support for systems with more than one CPU. If you have
261 a system with only one CPU, like most personal computers, say N. If
262 you have a system with more than one CPU, say Y.
264 If you say N here, the kernel will run on single and multiprocessor
265 machines, but will use only one CPU of a multiprocessor machine. If
266 you say Y here, the kernel will run on many, but not all,
267 singleprocessor machines. On a singleprocessor machine, the kernel
268 will run faster if you say N here.
270 Note that if you say Y here and choose architecture "586" or
271 "Pentium" under "Processor family", the kernel will not work on 486
272 architectures. Similarly, multiprocessor kernels for the "PPro"
273 architecture may not work on all Pentium based boards.
275 People using multiprocessor machines who say Y here should also say
276 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
277 Management" code will be disabled if you say Y here.
279 See also <file:Documentation/i386/IO-APIC.txt>,
280 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
281 <http://www.tldp.org/docs.html#howto>.
283 If you don't know what to do here, say N.
286 bool "Support x2apic"
287 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
289 This enables x2apic support on CPUs that have this feature.
291 This allows 32-bit apic IDs (so it can support very large systems),
292 and accesses the local apic via MSRs not via mmio.
294 If you don't know what to do here, say N.
297 bool "Support sparse irq numbering"
298 depends on PCI_MSI || HT_IRQ
300 This enables support for sparse irqs. This is useful for distro
301 kernels that want to define a high CONFIG_NR_CPUS value but still
302 want to have low kernel memory footprint on smaller machines.
304 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
305 out the irq_desc[] array in a more NUMA-friendly way. )
307 If you don't know what to do here, say N.
311 depends on SPARSE_IRQ && NUMA
314 bool "Enable MPS table" if ACPI
316 depends on X86_LOCAL_APIC
318 For old smp systems that do not have proper acpi support. Newer systems
319 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
322 bool "Support for big SMP systems with more than 8 CPUs"
323 depends on X86_32 && SMP
325 This option is needed for the systems that have more than 8 CPUs
328 config X86_EXTENDED_PLATFORM
329 bool "Support for extended (non-PC) x86 platforms"
332 If you disable this option then the kernel will only support
333 standard PC platforms. (which covers the vast majority of
336 If you enable this option then you'll be able to select support
337 for the following (non-PC) 32 bit x86 platforms:
341 SGI 320/540 (Visual Workstation)
342 Summit/EXA (IBM x440)
343 Unisys ES7000 IA32 series
344 Moorestown MID devices
346 If you have one of these systems, or if you want to build a
347 generic distribution kernel, say Y here - otherwise say N.
351 config X86_EXTENDED_PLATFORM
352 bool "Support for extended (non-PC) x86 platforms"
355 If you disable this option then the kernel will only support
356 standard PC platforms. (which covers the vast majority of
359 If you enable this option then you'll be able to select support
360 for the following (non-PC) 64 bit x86 platforms:
364 If you have one of these systems, or if you want to build a
365 generic distribution kernel, say Y here - otherwise say N.
367 # This is an alphabetically sorted list of 64 bit extended platforms
368 # Please maintain the alphabetic order if and when there are additions
373 depends on X86_64 && PCI
374 depends on X86_EXTENDED_PLATFORM
376 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
377 supposed to run on these EM64T-based machines. Only choose this option
378 if you have one of these machines.
381 bool "SGI Ultraviolet"
383 depends on X86_EXTENDED_PLATFORM
385 depends on X86_X2APIC
387 This option is needed in order to support SGI Ultraviolet systems.
388 If you don't have one of these, you should say N here.
390 # Following is an alphabetically sorted list of 32 bit extended platforms
391 # Please maintain the alphabetic order if and when there are additions
396 depends on X86_EXTENDED_PLATFORM
398 Select this for an AMD Elan processor.
400 Do not use this option for K6/Athlon/Opteron processors!
402 If unsure, choose "PC-compatible" instead.
405 bool "Moorestown MID platform"
409 depends on X86_EXTENDED_PLATFORM
410 depends on X86_IO_APIC
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.
493 config SCHED_OMIT_FRAME_POINTER
495 prompt "Single-depth WCHAN output"
498 Calculate simpler /proc/<PID>/wchan values. If this option
499 is disabled then wchan values will recurse back to the
500 caller function. This provides more accurate wchan values,
501 at the expense of slightly more scheduling overhead.
503 If in doubt, say "Y".
505 menuconfig PARAVIRT_GUEST
506 bool "Paravirtualized guest support"
508 Say Y here to get to see options related to running Linux under
509 various hypervisors. This option alone does not add any kernel code.
511 If you say N, all options in this submenu will be skipped and disabled.
515 source "arch/x86/xen/Kconfig"
518 bool "VMI Guest support (DEPRECATED)"
522 VMI provides a paravirtualized interface to the VMware ESX server
523 (it could be used by other hypervisors in theory too, but is not
524 at the moment), by linking the kernel to a GPL-ed ROM module
525 provided by the hypervisor.
527 As of September 2009, VMware has started a phased retirement
528 of this feature from VMware's products. Please see
529 feature-removal-schedule.txt for details. If you are
530 planning to enable this option, please note that you cannot
531 live migrate a VMI enabled VM to a future VMware product,
532 which doesn't support VMI. So if you expect your kernel to
533 seamlessly migrate to newer VMware products, keep this
537 bool "KVM paravirtualized clock"
539 select PARAVIRT_CLOCK
541 Turning on this option will allow you to run a paravirtualized clock
542 when running over the KVM hypervisor. Instead of relying on a PIT
543 (or probably other) emulation by the underlying device model, the host
544 provides the guest with timing infrastructure such as time of day, and
548 bool "KVM Guest support"
551 This option enables various optimizations for running under the KVM
554 source "arch/x86/lguest/Kconfig"
557 bool "Enable paravirtualization code"
559 This changes the kernel so it can modify itself when it is run
560 under a hypervisor, potentially improving performance significantly
561 over full virtualization. However, when run without a hypervisor
562 the kernel is theoretically slower and slightly larger.
564 config PARAVIRT_SPINLOCKS
565 bool "Paravirtualization layer for spinlocks"
566 depends on PARAVIRT && SMP && EXPERIMENTAL
568 Paravirtualized spinlocks allow a pvops backend to replace the
569 spinlock implementation with something virtualization-friendly
570 (for example, block the virtual CPU rather than spinning).
572 Unfortunately the downside is an up to 5% performance hit on
573 native kernels, with various workloads.
575 If you are unsure how to answer this question, answer N.
577 config PARAVIRT_CLOCK
582 config PARAVIRT_DEBUG
583 bool "paravirt-ops debugging"
584 depends on PARAVIRT && DEBUG_KERNEL
586 Enable to debug paravirt_ops internals. Specifically, BUG if
587 a paravirt_op is missing when it is called.
591 bool "Disable Bootmem code"
593 Use early_res directly instead of bootmem before slab is ready.
594 - allocator (buddy) [generic]
595 - early allocator (bootmem) [generic]
596 - very early allocator (reserve_early*()) [x86]
597 - very very early allocator (early brk model) [x86]
598 So reduce one layer between early allocator to final allocator
604 This option adds a kernel parameter 'memtest', which allows memtest
606 memtest=0, mean disabled; -- default
607 memtest=1, mean do 1 test pattern;
609 memtest=4, mean do 4 test patterns.
610 If you are unsure how to answer this question, answer N.
612 config X86_SUMMIT_NUMA
614 depends on X86_32 && NUMA && X86_32_NON_STANDARD
616 config X86_CYCLONE_TIMER
618 depends on X86_32_NON_STANDARD
620 source "arch/x86/Kconfig.cpu"
624 prompt "HPET Timer Support" if X86_32
626 Use the IA-PC HPET (High Precision Event Timer) to manage
627 time in preference to the PIT and RTC, if a HPET is
629 HPET is the next generation timer replacing legacy 8254s.
630 The HPET provides a stable time base on SMP
631 systems, unlike the TSC, but it is more expensive to access,
632 as it is off-chip. You can find the HPET spec at
633 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
635 You can safely choose Y here. However, HPET will only be
636 activated if the platform and the BIOS support this feature.
637 Otherwise the 8254 will be used for timing services.
639 Choose N to continue using the legacy 8254 timer.
641 config HPET_EMULATE_RTC
643 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
647 prompt "Langwell APB Timer Support" if X86_MRST
649 APB timer is the replacement for 8254, HPET on X86 MID platforms.
650 The APBT provides a stable time base on SMP
651 systems, unlike the TSC, but it is more expensive to access,
652 as it is off-chip. APB timers are always running regardless of CPU
653 C states, they are used as per CPU clockevent device when possible.
655 # Mark as embedded because too many people got it wrong.
656 # The code disables itself when not needed.
659 bool "Enable DMI scanning" if EMBEDDED
661 Enabled scanning of DMI to identify machine quirks. Say Y
662 here unless you have verified that your setup is not
663 affected by entries in the DMI blacklist. Required by PNP
667 bool "GART IOMMU support" if EMBEDDED
670 depends on X86_64 && PCI && K8_NB
672 Support for full DMA access of devices with 32bit memory access only
673 on systems with more than 3GB. This is usually needed for USB,
674 sound, many IDE/SATA chipsets and some other devices.
675 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
676 based hardware IOMMU and a software bounce buffer based IOMMU used
677 on Intel systems and as fallback.
678 The code is only active when needed (enough memory and limited
679 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
683 bool "IBM Calgary IOMMU support"
685 depends on X86_64 && PCI && EXPERIMENTAL
687 Support for hardware IOMMUs in IBM's xSeries x366 and x460
688 systems. Needed to run systems with more than 3GB of memory
689 properly with 32-bit PCI devices that do not support DAC
690 (Double Address Cycle). Calgary also supports bus level
691 isolation, where all DMAs pass through the IOMMU. This
692 prevents them from going anywhere except their intended
693 destination. This catches hard-to-find kernel bugs and
694 mis-behaving drivers and devices that do not use the DMA-API
695 properly to set up their DMA buffers. The IOMMU can be
696 turned off at boot time with the iommu=off parameter.
697 Normally the kernel will make the right choice by itself.
700 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
702 prompt "Should Calgary be enabled by default?"
703 depends on CALGARY_IOMMU
705 Should Calgary be enabled by default? if you choose 'y', Calgary
706 will be used (if it exists). If you choose 'n', Calgary will not be
707 used even if it exists. If you choose 'n' and would like to use
708 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
712 bool "AMD IOMMU support"
715 depends on X86_64 && PCI && ACPI
717 With this option you can enable support for AMD IOMMU hardware in
718 your system. An IOMMU is a hardware component which provides
719 remapping of DMA memory accesses from devices. With an AMD IOMMU you
720 can isolate the the DMA memory of different devices and protect the
721 system from misbehaving device drivers or hardware.
723 You can find out if your system has an AMD IOMMU if you look into
724 your BIOS for an option to enable it or if you have an IVRS ACPI
727 config AMD_IOMMU_STATS
728 bool "Export AMD IOMMU statistics to debugfs"
732 This option enables code in the AMD IOMMU driver to collect various
733 statistics about whats happening in the driver and exports that
734 information to userspace via debugfs.
737 # need this always selected by IOMMU for the VIA workaround
741 Support for software bounce buffers used on x86-64 systems
742 which don't have a hardware IOMMU (e.g. the current generation
743 of Intel's x86-64 CPUs). Using this PCI devices which can only
744 access 32-bits of memory can be used on systems with more than
745 3 GB of memory. If unsure, say Y.
748 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
751 def_bool (AMD_IOMMU || DMAR)
754 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
755 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
756 select CPUMASK_OFFSTACK
758 Configure maximum number of CPUS and NUMA Nodes for this architecture.
762 int "Maximum number of CPUs" if SMP && !MAXSMP
763 range 2 8 if SMP && X86_32 && !X86_BIGSMP
764 range 2 512 if SMP && !MAXSMP
766 default "4096" if MAXSMP
767 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
770 This allows you to specify the maximum number of CPUs which this
771 kernel will support. The maximum supported value is 512 and the
772 minimum value which makes sense is 2.
774 This is purely to save memory - each supported CPU adds
775 approximately eight kilobytes to the kernel image.
778 bool "SMT (Hyperthreading) scheduler support"
781 SMT scheduler support improves the CPU scheduler's decision making
782 when dealing with Intel Pentium 4 chips with HyperThreading at a
783 cost of slightly increased overhead in some places. If unsure say
788 prompt "Multi-core scheduler support"
791 Multi-core scheduler support improves the CPU scheduler's decision
792 making when dealing with multi-core CPU chips at a cost of slightly
793 increased overhead in some places. If unsure say N here.
795 source "kernel/Kconfig.preempt"
798 bool "Local APIC support on uniprocessors"
799 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
801 A local APIC (Advanced Programmable Interrupt Controller) is an
802 integrated interrupt controller in the CPU. If you have a single-CPU
803 system which has a processor with a local APIC, you can say Y here to
804 enable and use it. If you say Y here even though your machine doesn't
805 have a local APIC, then the kernel will still run with no slowdown at
806 all. The local APIC supports CPU-generated self-interrupts (timer,
807 performance counters), and the NMI watchdog which detects hard
811 bool "IO-APIC support on uniprocessors"
812 depends on X86_UP_APIC
814 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
815 SMP-capable replacement for PC-style interrupt controllers. Most
816 SMP systems and many recent uniprocessor systems have one.
818 If you have a single-CPU system with an IO-APIC, you can say Y here
819 to use it. If you say Y here even though your machine doesn't have
820 an IO-APIC, then the kernel will still run with no slowdown at all.
822 config X86_LOCAL_APIC
824 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
828 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
830 config X86_VISWS_APIC
832 depends on X86_32 && X86_VISWS
834 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
835 bool "Reroute for broken boot IRQs"
836 depends on X86_IO_APIC
838 This option enables a workaround that fixes a source of
839 spurious interrupts. This is recommended when threaded
840 interrupt handling is used on systems where the generation of
841 superfluous "boot interrupts" cannot be disabled.
843 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
844 entry in the chipset's IO-APIC is masked (as, e.g. the RT
845 kernel does during interrupt handling). On chipsets where this
846 boot IRQ generation cannot be disabled, this workaround keeps
847 the original IRQ line masked so that only the equivalent "boot
848 IRQ" is delivered to the CPUs. The workaround also tells the
849 kernel to set up the IRQ handler on the boot IRQ line. In this
850 way only one interrupt is delivered to the kernel. Otherwise
851 the spurious second interrupt may cause the kernel to bring
852 down (vital) interrupt lines.
854 Only affects "broken" chipsets. Interrupt sharing may be
855 increased on these systems.
858 bool "Machine Check / overheating reporting"
860 Machine Check support allows the processor to notify the
861 kernel if it detects a problem (e.g. overheating, data corruption).
862 The action the kernel takes depends on the severity of the problem,
863 ranging from warning messages to halting the machine.
867 prompt "Intel MCE features"
868 depends on X86_MCE && X86_LOCAL_APIC
870 Additional support for intel specific MCE features such as
875 prompt "AMD MCE features"
876 depends on X86_MCE && X86_LOCAL_APIC
878 Additional support for AMD specific MCE features such as
879 the DRAM Error Threshold.
881 config X86_ANCIENT_MCE
882 bool "Support for old Pentium 5 / WinChip machine checks"
883 depends on X86_32 && X86_MCE
885 Include support for machine check handling on old Pentium 5 or WinChip
886 systems. These typically need to be enabled explicitely on the command
889 config X86_MCE_THRESHOLD
890 depends on X86_MCE_AMD || X86_MCE_INTEL
893 config X86_MCE_INJECT
895 tristate "Machine check injector support"
897 Provide support for injecting machine checks for testing purposes.
898 If you don't know what a machine check is and you don't do kernel
899 QA it is safe to say n.
901 config X86_THERMAL_VECTOR
903 depends on X86_MCE_INTEL
906 bool "Enable VM86 support" if EMBEDDED
910 This option is required by programs like DOSEMU to run 16-bit legacy
911 code on X86 processors. It also may be needed by software like
912 XFree86 to initialize some video cards via BIOS. Disabling this
913 option saves about 6k.
916 tristate "Toshiba Laptop support"
919 This adds a driver to safely access the System Management Mode of
920 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
921 not work on models with a Phoenix BIOS. The System Management Mode
922 is used to set the BIOS and power saving options on Toshiba portables.
924 For information on utilities to make use of this driver see the
925 Toshiba Linux utilities web site at:
926 <http://www.buzzard.org.uk/toshiba/>.
928 Say Y if you intend to run this kernel on a Toshiba portable.
932 tristate "Dell laptop support"
934 This adds a driver to safely access the System Management Mode
935 of the CPU on the Dell Inspiron 8000. The System Management Mode
936 is used to read cpu temperature and cooling fan status and to
937 control the fans on the I8K portables.
939 This driver has been tested only on the Inspiron 8000 but it may
940 also work with other Dell laptops. You can force loading on other
941 models by passing the parameter `force=1' to the module. Use at
944 For information on utilities to make use of this driver see the
945 I8K Linux utilities web site at:
946 <http://people.debian.org/~dz/i8k/>
948 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
951 config X86_REBOOTFIXUPS
952 bool "Enable X86 board specific fixups for reboot"
955 This enables chipset and/or board specific fixups to be done
956 in order to get reboot to work correctly. This is only needed on
957 some combinations of hardware and BIOS. The symptom, for which
958 this config is intended, is when reboot ends with a stalled/hung
961 Currently, the only fixup is for the Geode machines using
962 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
964 Say Y if you want to enable the fixup. Currently, it's safe to
965 enable this option even if you don't need it.
969 tristate "/dev/cpu/microcode - microcode support"
972 If you say Y here, you will be able to update the microcode on
973 certain Intel and AMD processors. The Intel support is for the
974 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
975 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
976 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
977 You will obviously need the actual microcode binary data itself
978 which is not shipped with the Linux kernel.
980 This option selects the general module only, you need to select
981 at least one vendor specific module as well.
983 To compile this driver as a module, choose M here: the
984 module will be called microcode.
986 config MICROCODE_INTEL
987 bool "Intel microcode patch loading support"
992 This options enables microcode patch loading support for Intel
995 For latest news and information on obtaining all the required
996 Intel ingredients for this driver, check:
997 <http://www.urbanmyth.org/microcode/>.
1000 bool "AMD microcode patch loading support"
1001 depends on MICROCODE
1004 If you select this option, microcode patch loading support for AMD
1005 processors will be enabled.
1007 config MICROCODE_OLD_INTERFACE
1009 depends on MICROCODE
1012 tristate "/dev/cpu/*/msr - Model-specific register support"
1014 This device gives privileged processes access to the x86
1015 Model-Specific Registers (MSRs). It is a character device with
1016 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1017 MSR accesses are directed to a specific CPU on multi-processor
1021 tristate "/dev/cpu/*/cpuid - CPU information support"
1023 This device gives processes access to the x86 CPUID instruction to
1024 be executed on a specific processor. It is a character device
1025 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1029 prompt "High Memory Support"
1030 default HIGHMEM64G if X86_NUMAQ
1036 depends on !X86_NUMAQ
1038 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1039 However, the address space of 32-bit x86 processors is only 4
1040 Gigabytes large. That means that, if you have a large amount of
1041 physical memory, not all of it can be "permanently mapped" by the
1042 kernel. The physical memory that's not permanently mapped is called
1045 If you are compiling a kernel which will never run on a machine with
1046 more than 1 Gigabyte total physical RAM, answer "off" here (default
1047 choice and suitable for most users). This will result in a "3GB/1GB"
1048 split: 3GB are mapped so that each process sees a 3GB virtual memory
1049 space and the remaining part of the 4GB virtual memory space is used
1050 by the kernel to permanently map as much physical memory as
1053 If the machine has between 1 and 4 Gigabytes physical RAM, then
1056 If more than 4 Gigabytes is used then answer "64GB" here. This
1057 selection turns Intel PAE (Physical Address Extension) mode on.
1058 PAE implements 3-level paging on IA32 processors. PAE is fully
1059 supported by Linux, PAE mode is implemented on all recent Intel
1060 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1061 then the kernel will not boot on CPUs that don't support PAE!
1063 The actual amount of total physical memory will either be
1064 auto detected or can be forced by using a kernel command line option
1065 such as "mem=256M". (Try "man bootparam" or see the documentation of
1066 your boot loader (lilo or loadlin) about how to pass options to the
1067 kernel at boot time.)
1069 If unsure, say "off".
1073 depends on !X86_NUMAQ
1075 Select this if you have a 32-bit processor and between 1 and 4
1076 gigabytes of physical RAM.
1080 depends on !M386 && !M486
1083 Select this if you have a 32-bit processor and more than 4
1084 gigabytes of physical RAM.
1089 depends on EXPERIMENTAL
1090 prompt "Memory split" if EMBEDDED
1094 Select the desired split between kernel and user memory.
1096 If the address range available to the kernel is less than the
1097 physical memory installed, the remaining memory will be available
1098 as "high memory". Accessing high memory is a little more costly
1099 than low memory, as it needs to be mapped into the kernel first.
1100 Note that increasing the kernel address space limits the range
1101 available to user programs, making the address space there
1102 tighter. Selecting anything other than the default 3G/1G split
1103 will also likely make your kernel incompatible with binary-only
1106 If you are not absolutely sure what you are doing, leave this
1110 bool "3G/1G user/kernel split"
1111 config VMSPLIT_3G_OPT
1113 bool "3G/1G user/kernel split (for full 1G low memory)"
1115 bool "2G/2G user/kernel split"
1116 config VMSPLIT_2G_OPT
1118 bool "2G/2G user/kernel split (for full 2G low memory)"
1120 bool "1G/3G user/kernel split"
1125 default 0xB0000000 if VMSPLIT_3G_OPT
1126 default 0x80000000 if VMSPLIT_2G
1127 default 0x78000000 if VMSPLIT_2G_OPT
1128 default 0x40000000 if VMSPLIT_1G
1134 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1137 bool "PAE (Physical Address Extension) Support"
1138 depends on X86_32 && !HIGHMEM4G
1140 PAE is required for NX support, and furthermore enables
1141 larger swapspace support for non-overcommit purposes. It
1142 has the cost of more pagetable lookup overhead, and also
1143 consumes more pagetable space per process.
1145 config ARCH_PHYS_ADDR_T_64BIT
1146 def_bool X86_64 || X86_PAE
1148 config DIRECT_GBPAGES
1149 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1153 Allow the kernel linear mapping to use 1GB pages on CPUs that
1154 support it. This can improve the kernel's performance a tiny bit by
1155 reducing TLB pressure. If in doubt, say "Y".
1157 # Common NUMA Features
1159 bool "Numa Memory Allocation and Scheduler Support"
1161 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1162 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1164 Enable NUMA (Non Uniform Memory Access) support.
1166 The kernel will try to allocate memory used by a CPU on the
1167 local memory controller of the CPU and add some more
1168 NUMA awareness to the kernel.
1170 For 64-bit this is recommended if the system is Intel Core i7
1171 (or later), AMD Opteron, or EM64T NUMA.
1173 For 32-bit this is only needed on (rare) 32-bit-only platforms
1174 that support NUMA topologies, such as NUMAQ / Summit, or if you
1175 boot a 32-bit kernel on a 64-bit NUMA platform.
1177 Otherwise, you should say N.
1179 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1180 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1184 prompt "Old style AMD Opteron NUMA detection"
1185 depends on X86_64 && NUMA && PCI
1187 Enable K8 NUMA node topology detection. You should say Y here if
1188 you have a multi processor AMD K8 system. This uses an old
1189 method to read the NUMA configuration directly from the builtin
1190 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1191 instead, which also takes priority if both are compiled in.
1193 config X86_64_ACPI_NUMA
1195 prompt "ACPI NUMA detection"
1196 depends on X86_64 && NUMA && ACPI && PCI
1199 Enable ACPI SRAT based node topology detection.
1201 # Some NUMA nodes have memory ranges that span
1202 # other nodes. Even though a pfn is valid and
1203 # between a node's start and end pfns, it may not
1204 # reside on that node. See memmap_init_zone()
1206 config NODES_SPAN_OTHER_NODES
1208 depends on X86_64_ACPI_NUMA
1211 bool "NUMA emulation"
1212 depends on X86_64 && NUMA
1214 Enable NUMA emulation. A flat machine will be split
1215 into virtual nodes when booted with "numa=fake=N", where N is the
1216 number of nodes. This is only useful for debugging.
1219 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1221 default "10" if MAXSMP
1222 default "6" if X86_64
1223 default "4" if X86_NUMAQ
1225 depends on NEED_MULTIPLE_NODES
1227 Specify the maximum number of NUMA Nodes available on the target
1228 system. Increases memory reserved to accommodate various tables.
1230 config HAVE_ARCH_BOOTMEM
1232 depends on X86_32 && NUMA
1234 config ARCH_HAVE_MEMORY_PRESENT
1236 depends on X86_32 && DISCONTIGMEM
1238 config NEED_NODE_MEMMAP_SIZE
1240 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1242 config HAVE_ARCH_ALLOC_REMAP
1244 depends on X86_32 && NUMA
1246 config ARCH_FLATMEM_ENABLE
1248 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1250 config ARCH_DISCONTIGMEM_ENABLE
1252 depends on NUMA && X86_32
1254 config ARCH_DISCONTIGMEM_DEFAULT
1256 depends on NUMA && X86_32
1258 config ARCH_PROC_KCORE_TEXT
1260 depends on X86_64 && PROC_KCORE
1262 config ARCH_SPARSEMEM_DEFAULT
1266 config ARCH_SPARSEMEM_ENABLE
1268 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1269 select SPARSEMEM_STATIC if X86_32
1270 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1272 config ARCH_SELECT_MEMORY_MODEL
1274 depends on ARCH_SPARSEMEM_ENABLE
1276 config ARCH_MEMORY_PROBE
1278 depends on MEMORY_HOTPLUG
1280 config ILLEGAL_POINTER_VALUE
1283 default 0xdead000000000000 if X86_64
1288 bool "Allocate 3rd-level pagetables from highmem"
1291 The VM uses one page table entry for each page of physical memory.
1292 For systems with a lot of RAM, this can be wasteful of precious
1293 low memory. Setting this option will put user-space page table
1294 entries in high memory.
1296 config X86_CHECK_BIOS_CORRUPTION
1297 bool "Check for low memory corruption"
1299 Periodically check for memory corruption in low memory, which
1300 is suspected to be caused by BIOS. Even when enabled in the
1301 configuration, it is disabled at runtime. Enable it by
1302 setting "memory_corruption_check=1" on the kernel command
1303 line. By default it scans the low 64k of memory every 60
1304 seconds; see the memory_corruption_check_size and
1305 memory_corruption_check_period parameters in
1306 Documentation/kernel-parameters.txt to adjust this.
1308 When enabled with the default parameters, this option has
1309 almost no overhead, as it reserves a relatively small amount
1310 of memory and scans it infrequently. It both detects corruption
1311 and prevents it from affecting the running system.
1313 It is, however, intended as a diagnostic tool; if repeatable
1314 BIOS-originated corruption always affects the same memory,
1315 you can use memmap= to prevent the kernel from using that
1318 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1319 bool "Set the default setting of memory_corruption_check"
1320 depends on X86_CHECK_BIOS_CORRUPTION
1323 Set whether the default state of memory_corruption_check is
1326 config X86_RESERVE_LOW_64K
1327 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1330 Reserve the first 64K of physical RAM on BIOSes that are known
1331 to potentially corrupt that memory range. A numbers of BIOSes are
1332 known to utilize this area during suspend/resume, so it must not
1333 be used by the kernel.
1335 Set this to N if you are absolutely sure that you trust the BIOS
1336 to get all its memory reservations and usages right.
1338 If you have doubts about the BIOS (e.g. suspend/resume does not
1339 work or there's kernel crashes after certain hardware hotplug
1340 events) and it's not AMI or Phoenix, then you might want to enable
1341 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1342 corruption patterns.
1346 config MATH_EMULATION
1348 prompt "Math emulation" if X86_32
1350 Linux can emulate a math coprocessor (used for floating point
1351 operations) if you don't have one. 486DX and Pentium processors have
1352 a math coprocessor built in, 486SX and 386 do not, unless you added
1353 a 487DX or 387, respectively. (The messages during boot time can
1354 give you some hints here ["man dmesg"].) Everyone needs either a
1355 coprocessor or this emulation.
1357 If you don't have a math coprocessor, you need to say Y here; if you
1358 say Y here even though you have a coprocessor, the coprocessor will
1359 be used nevertheless. (This behavior can be changed with the kernel
1360 command line option "no387", which comes handy if your coprocessor
1361 is broken. Try "man bootparam" or see the documentation of your boot
1362 loader (lilo or loadlin) about how to pass options to the kernel at
1363 boot time.) This means that it is a good idea to say Y here if you
1364 intend to use this kernel on different machines.
1366 More information about the internals of the Linux math coprocessor
1367 emulation can be found in <file:arch/x86/math-emu/README>.
1369 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1370 kernel, it won't hurt.
1374 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1376 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1377 the Memory Type Range Registers (MTRRs) may be used to control
1378 processor access to memory ranges. This is most useful if you have
1379 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1380 allows bus write transfers to be combined into a larger transfer
1381 before bursting over the PCI/AGP bus. This can increase performance
1382 of image write operations 2.5 times or more. Saying Y here creates a
1383 /proc/mtrr file which may be used to manipulate your processor's
1384 MTRRs. Typically the X server should use this.
1386 This code has a reasonably generic interface so that similar
1387 control registers on other processors can be easily supported
1390 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1391 Registers (ARRs) which provide a similar functionality to MTRRs. For
1392 these, the ARRs are used to emulate the MTRRs.
1393 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1394 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1395 write-combining. All of these processors are supported by this code
1396 and it makes sense to say Y here if you have one of them.
1398 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1399 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1400 can lead to all sorts of problems, so it's good to say Y here.
1402 You can safely say Y even if your machine doesn't have MTRRs, you'll
1403 just add about 9 KB to your kernel.
1405 See <file:Documentation/x86/mtrr.txt> for more information.
1407 config MTRR_SANITIZER
1409 prompt "MTRR cleanup support"
1412 Convert MTRR layout from continuous to discrete, so X drivers can
1413 add writeback entries.
1415 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1416 The largest mtrr entry size for a continuous block can be set with
1421 config MTRR_SANITIZER_ENABLE_DEFAULT
1422 int "MTRR cleanup enable value (0-1)"
1425 depends on MTRR_SANITIZER
1427 Enable mtrr cleanup default value
1429 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1430 int "MTRR cleanup spare reg num (0-7)"
1433 depends on MTRR_SANITIZER
1435 mtrr cleanup spare entries default, it can be changed via
1436 mtrr_spare_reg_nr=N on the kernel command line.
1440 prompt "x86 PAT support" if EMBEDDED
1443 Use PAT attributes to setup page level cache control.
1445 PATs are the modern equivalents of MTRRs and are much more
1446 flexible than MTRRs.
1448 Say N here if you see bootup problems (boot crash, boot hang,
1449 spontaneous reboots) or a non-working video driver.
1453 config ARCH_USES_PG_UNCACHED
1458 bool "EFI runtime service support"
1461 This enables the kernel to use EFI runtime services that are
1462 available (such as the EFI variable services).
1464 This option is only useful on systems that have EFI firmware.
1465 In addition, you should use the latest ELILO loader available
1466 at <http://elilo.sourceforge.net> in order to take advantage
1467 of EFI runtime services. However, even with this option, the
1468 resultant kernel should continue to boot on existing non-EFI
1473 prompt "Enable seccomp to safely compute untrusted bytecode"
1475 This kernel feature is useful for number crunching applications
1476 that may need to compute untrusted bytecode during their
1477 execution. By using pipes or other transports made available to
1478 the process as file descriptors supporting the read/write
1479 syscalls, it's possible to isolate those applications in
1480 their own address space using seccomp. Once seccomp is
1481 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1482 and the task is only allowed to execute a few safe syscalls
1483 defined by each seccomp mode.
1485 If unsure, say Y. Only embedded should say N here.
1487 config CC_STACKPROTECTOR
1488 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1490 This option turns on the -fstack-protector GCC feature. This
1491 feature puts, at the beginning of functions, a canary value on
1492 the stack just before the return address, and validates
1493 the value just before actually returning. Stack based buffer
1494 overflows (that need to overwrite this return address) now also
1495 overwrite the canary, which gets detected and the attack is then
1496 neutralized via a kernel panic.
1498 This feature requires gcc version 4.2 or above, or a distribution
1499 gcc with the feature backported. Older versions are automatically
1500 detected and for those versions, this configuration option is
1501 ignored. (and a warning is printed during bootup)
1503 source kernel/Kconfig.hz
1506 bool "kexec system call"
1508 kexec is a system call that implements the ability to shutdown your
1509 current kernel, and to start another kernel. It is like a reboot
1510 but it is independent of the system firmware. And like a reboot
1511 you can start any kernel with it, not just Linux.
1513 The name comes from the similarity to the exec system call.
1515 It is an ongoing process to be certain the hardware in a machine
1516 is properly shutdown, so do not be surprised if this code does not
1517 initially work for you. It may help to enable device hotplugging
1518 support. As of this writing the exact hardware interface is
1519 strongly in flux, so no good recommendation can be made.
1522 bool "kernel crash dumps"
1523 depends on X86_64 || (X86_32 && HIGHMEM)
1525 Generate crash dump after being started by kexec.
1526 This should be normally only set in special crash dump kernels
1527 which are loaded in the main kernel with kexec-tools into
1528 a specially reserved region and then later executed after
1529 a crash by kdump/kexec. The crash dump kernel must be compiled
1530 to a memory address not used by the main kernel or BIOS using
1531 PHYSICAL_START, or it must be built as a relocatable image
1532 (CONFIG_RELOCATABLE=y).
1533 For more details see Documentation/kdump/kdump.txt
1536 bool "kexec jump (EXPERIMENTAL)"
1537 depends on EXPERIMENTAL
1538 depends on KEXEC && HIBERNATION
1540 Jump between original kernel and kexeced kernel and invoke
1541 code in physical address mode via KEXEC
1543 config PHYSICAL_START
1544 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1547 This gives the physical address where the kernel is loaded.
1549 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1550 bzImage will decompress itself to above physical address and
1551 run from there. Otherwise, bzImage will run from the address where
1552 it has been loaded by the boot loader and will ignore above physical
1555 In normal kdump cases one does not have to set/change this option
1556 as now bzImage can be compiled as a completely relocatable image
1557 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1558 address. This option is mainly useful for the folks who don't want
1559 to use a bzImage for capturing the crash dump and want to use a
1560 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1561 to be specifically compiled to run from a specific memory area
1562 (normally a reserved region) and this option comes handy.
1564 So if you are using bzImage for capturing the crash dump,
1565 leave the value here unchanged to 0x1000000 and set
1566 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1567 for capturing the crash dump change this value to start of
1568 the reserved region. In other words, it can be set based on
1569 the "X" value as specified in the "crashkernel=YM@XM"
1570 command line boot parameter passed to the panic-ed
1571 kernel. Please take a look at Documentation/kdump/kdump.txt
1572 for more details about crash dumps.
1574 Usage of bzImage for capturing the crash dump is recommended as
1575 one does not have to build two kernels. Same kernel can be used
1576 as production kernel and capture kernel. Above option should have
1577 gone away after relocatable bzImage support is introduced. But it
1578 is present because there are users out there who continue to use
1579 vmlinux for dump capture. This option should go away down the
1582 Don't change this unless you know what you are doing.
1585 bool "Build a relocatable kernel"
1588 This builds a kernel image that retains relocation information
1589 so it can be loaded someplace besides the default 1MB.
1590 The relocations tend to make the kernel binary about 10% larger,
1591 but are discarded at runtime.
1593 One use is for the kexec on panic case where the recovery kernel
1594 must live at a different physical address than the primary
1597 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1598 it has been loaded at and the compile time physical address
1599 (CONFIG_PHYSICAL_START) is ignored.
1601 # Relocation on x86-32 needs some additional build support
1602 config X86_NEED_RELOCS
1604 depends on X86_32 && RELOCATABLE
1606 config PHYSICAL_ALIGN
1607 hex "Alignment value to which kernel should be aligned" if X86_32
1609 range 0x2000 0x1000000
1611 This value puts the alignment restrictions on physical address
1612 where kernel is loaded and run from. Kernel is compiled for an
1613 address which meets above alignment restriction.
1615 If bootloader loads the kernel at a non-aligned address and
1616 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1617 address aligned to above value and run from there.
1619 If bootloader loads the kernel at a non-aligned address and
1620 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1621 load address and decompress itself to the address it has been
1622 compiled for and run from there. The address for which kernel is
1623 compiled already meets above alignment restrictions. Hence the
1624 end result is that kernel runs from a physical address meeting
1625 above alignment restrictions.
1627 Don't change this unless you know what you are doing.
1630 bool "Support for hot-pluggable CPUs"
1631 depends on SMP && HOTPLUG
1633 Say Y here to allow turning CPUs off and on. CPUs can be
1634 controlled through /sys/devices/system/cpu.
1635 ( Note: power management support will enable this option
1636 automatically on SMP systems. )
1637 Say N if you want to disable CPU hotplug.
1641 prompt "Compat VDSO support"
1642 depends on X86_32 || IA32_EMULATION
1644 Map the 32-bit VDSO to the predictable old-style address too.
1646 Say N here if you are running a sufficiently recent glibc
1647 version (2.3.3 or later), to remove the high-mapped
1648 VDSO mapping and to exclusively use the randomized VDSO.
1653 bool "Built-in kernel command line"
1655 Allow for specifying boot arguments to the kernel at
1656 build time. On some systems (e.g. embedded ones), it is
1657 necessary or convenient to provide some or all of the
1658 kernel boot arguments with the kernel itself (that is,
1659 to not rely on the boot loader to provide them.)
1661 To compile command line arguments into the kernel,
1662 set this option to 'Y', then fill in the
1663 the boot arguments in CONFIG_CMDLINE.
1665 Systems with fully functional boot loaders (i.e. non-embedded)
1666 should leave this option set to 'N'.
1669 string "Built-in kernel command string"
1670 depends on CMDLINE_BOOL
1673 Enter arguments here that should be compiled into the kernel
1674 image and used at boot time. If the boot loader provides a
1675 command line at boot time, it is appended to this string to
1676 form the full kernel command line, when the system boots.
1678 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1679 change this behavior.
1681 In most cases, the command line (whether built-in or provided
1682 by the boot loader) should specify the device for the root
1685 config CMDLINE_OVERRIDE
1686 bool "Built-in command line overrides boot loader arguments"
1687 depends on CMDLINE_BOOL
1689 Set this option to 'Y' to have the kernel ignore the boot loader
1690 command line, and use ONLY the built-in command line.
1692 This is used to work around broken boot loaders. This should
1693 be set to 'N' under normal conditions.
1697 config ARCH_ENABLE_MEMORY_HOTPLUG
1699 depends on X86_64 || (X86_32 && HIGHMEM)
1701 config ARCH_ENABLE_MEMORY_HOTREMOVE
1703 depends on MEMORY_HOTPLUG
1705 config HAVE_ARCH_EARLY_PFN_TO_NID
1709 config USE_PERCPU_NUMA_NODE_ID
1713 menu "Power management and ACPI options"
1715 config ARCH_HIBERNATION_HEADER
1717 depends on X86_64 && HIBERNATION
1719 source "kernel/power/Kconfig"
1721 source "drivers/acpi/Kconfig"
1723 source "drivers/sfi/Kconfig"
1727 depends on APM || APM_MODULE
1730 tristate "APM (Advanced Power Management) BIOS support"
1731 depends on X86_32 && PM_SLEEP
1733 APM is a BIOS specification for saving power using several different
1734 techniques. This is mostly useful for battery powered laptops with
1735 APM compliant BIOSes. If you say Y here, the system time will be
1736 reset after a RESUME operation, the /proc/apm device will provide
1737 battery status information, and user-space programs will receive
1738 notification of APM "events" (e.g. battery status change).
1740 If you select "Y" here, you can disable actual use of the APM
1741 BIOS by passing the "apm=off" option to the kernel at boot time.
1743 Note that the APM support is almost completely disabled for
1744 machines with more than one CPU.
1746 In order to use APM, you will need supporting software. For location
1747 and more information, read <file:Documentation/power/pm.txt> and the
1748 Battery Powered Linux mini-HOWTO, available from
1749 <http://www.tldp.org/docs.html#howto>.
1751 This driver does not spin down disk drives (see the hdparm(8)
1752 manpage ("man 8 hdparm") for that), and it doesn't turn off
1753 VESA-compliant "green" monitors.
1755 This driver does not support the TI 4000M TravelMate and the ACER
1756 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1757 desktop machines also don't have compliant BIOSes, and this driver
1758 may cause those machines to panic during the boot phase.
1760 Generally, if you don't have a battery in your machine, there isn't
1761 much point in using this driver and you should say N. If you get
1762 random kernel OOPSes or reboots that don't seem to be related to
1763 anything, try disabling/enabling this option (or disabling/enabling
1766 Some other things you should try when experiencing seemingly random,
1769 1) make sure that you have enough swap space and that it is
1771 2) pass the "no-hlt" option to the kernel
1772 3) switch on floating point emulation in the kernel and pass
1773 the "no387" option to the kernel
1774 4) pass the "floppy=nodma" option to the kernel
1775 5) pass the "mem=4M" option to the kernel (thereby disabling
1776 all but the first 4 MB of RAM)
1777 6) make sure that the CPU is not over clocked.
1778 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1779 8) disable the cache from your BIOS settings
1780 9) install a fan for the video card or exchange video RAM
1781 10) install a better fan for the CPU
1782 11) exchange RAM chips
1783 12) exchange the motherboard.
1785 To compile this driver as a module, choose M here: the
1786 module will be called apm.
1790 config APM_IGNORE_USER_SUSPEND
1791 bool "Ignore USER SUSPEND"
1793 This option will ignore USER SUSPEND requests. On machines with a
1794 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1795 series notebooks, it is necessary to say Y because of a BIOS bug.
1797 config APM_DO_ENABLE
1798 bool "Enable PM at boot time"
1800 Enable APM features at boot time. From page 36 of the APM BIOS
1801 specification: "When disabled, the APM BIOS does not automatically
1802 power manage devices, enter the Standby State, enter the Suspend
1803 State, or take power saving steps in response to CPU Idle calls."
1804 This driver will make CPU Idle calls when Linux is idle (unless this
1805 feature is turned off -- see "Do CPU IDLE calls", below). This
1806 should always save battery power, but more complicated APM features
1807 will be dependent on your BIOS implementation. You may need to turn
1808 this option off if your computer hangs at boot time when using APM
1809 support, or if it beeps continuously instead of suspending. Turn
1810 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1811 T400CDT. This is off by default since most machines do fine without
1815 bool "Make CPU Idle calls when idle"
1817 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1818 On some machines, this can activate improved power savings, such as
1819 a slowed CPU clock rate, when the machine is idle. These idle calls
1820 are made after the idle loop has run for some length of time (e.g.,
1821 333 mS). On some machines, this will cause a hang at boot time or
1822 whenever the CPU becomes idle. (On machines with more than one CPU,
1823 this option does nothing.)
1825 config APM_DISPLAY_BLANK
1826 bool "Enable console blanking using APM"
1828 Enable console blanking using the APM. Some laptops can use this to
1829 turn off the LCD backlight when the screen blanker of the Linux
1830 virtual console blanks the screen. Note that this is only used by
1831 the virtual console screen blanker, and won't turn off the backlight
1832 when using the X Window system. This also doesn't have anything to
1833 do with your VESA-compliant power-saving monitor. Further, this
1834 option doesn't work for all laptops -- it might not turn off your
1835 backlight at all, or it might print a lot of errors to the console,
1836 especially if you are using gpm.
1838 config APM_ALLOW_INTS
1839 bool "Allow interrupts during APM BIOS calls"
1841 Normally we disable external interrupts while we are making calls to
1842 the APM BIOS as a measure to lessen the effects of a badly behaving
1843 BIOS implementation. The BIOS should reenable interrupts if it
1844 needs to. Unfortunately, some BIOSes do not -- especially those in
1845 many of the newer IBM Thinkpads. If you experience hangs when you
1846 suspend, try setting this to Y. Otherwise, say N.
1850 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1852 source "drivers/cpuidle/Kconfig"
1854 source "drivers/idle/Kconfig"
1859 menu "Bus options (PCI etc.)"
1864 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1866 Find out whether you have a PCI motherboard. PCI is the name of a
1867 bus system, i.e. the way the CPU talks to the other stuff inside
1868 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1869 VESA. If you have PCI, say Y, otherwise N.
1872 prompt "PCI access mode"
1873 depends on X86_32 && PCI
1876 On PCI systems, the BIOS can be used to detect the PCI devices and
1877 determine their configuration. However, some old PCI motherboards
1878 have BIOS bugs and may crash if this is done. Also, some embedded
1879 PCI-based systems don't have any BIOS at all. Linux can also try to
1880 detect the PCI hardware directly without using the BIOS.
1882 With this option, you can specify how Linux should detect the
1883 PCI devices. If you choose "BIOS", the BIOS will be used,
1884 if you choose "Direct", the BIOS won't be used, and if you
1885 choose "MMConfig", then PCI Express MMCONFIG will be used.
1886 If you choose "Any", the kernel will try MMCONFIG, then the
1887 direct access method and falls back to the BIOS if that doesn't
1888 work. If unsure, go with the default, which is "Any".
1893 config PCI_GOMMCONFIG
1910 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1912 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1915 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1919 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1923 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1930 bool "Support mmconfig PCI config space access"
1931 depends on X86_64 && PCI && ACPI
1933 config PCI_CNB20LE_QUIRK
1934 bool "Read CNB20LE Host Bridge Windows"
1937 Read the PCI windows out of the CNB20LE host bridge. This allows
1938 PCI hotplug to work on systems with the CNB20LE chipset which do
1942 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1943 depends on PCI_MSI && ACPI && EXPERIMENTAL
1945 DMA remapping (DMAR) devices support enables independent address
1946 translations for Direct Memory Access (DMA) from devices.
1947 These DMA remapping devices are reported via ACPI tables
1948 and include PCI device scope covered by these DMA
1951 config DMAR_DEFAULT_ON
1953 prompt "Enable DMA Remapping Devices by default"
1956 Selecting this option will enable a DMAR device at boot time if
1957 one is found. If this option is not selected, DMAR support can
1958 be enabled by passing intel_iommu=on to the kernel. It is
1959 recommended you say N here while the DMAR code remains
1962 config DMAR_BROKEN_GFX_WA
1963 bool "Workaround broken graphics drivers (going away soon)"
1964 depends on DMAR && BROKEN
1966 Current Graphics drivers tend to use physical address
1967 for DMA and avoid using DMA APIs. Setting this config
1968 option permits the IOMMU driver to set a unity map for
1969 all the OS-visible memory. Hence the driver can continue
1970 to use physical addresses for DMA, at least until this
1971 option is removed in the 2.6.32 kernel.
1973 config DMAR_FLOPPY_WA
1977 Floppy disk drivers are known to bypass DMA API calls
1978 thereby failing to work when IOMMU is enabled. This
1979 workaround will setup a 1:1 mapping for the first
1980 16MiB to make floppy (an ISA device) work.
1983 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1984 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1986 Supports Interrupt remapping for IO-APIC and MSI devices.
1987 To use x2apic mode in the CPU's which support x2APIC enhancements or
1988 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1990 source "drivers/pci/pcie/Kconfig"
1992 source "drivers/pci/Kconfig"
1994 # x86_64 have no ISA slots, but do have ISA-style DMA.
2003 Find out whether you have ISA slots on your motherboard. ISA is the
2004 name of a bus system, i.e. the way the CPU talks to the other stuff
2005 inside your box. Other bus systems are PCI, EISA, MicroChannel
2006 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2007 newer boards don't support it. If you have ISA, say Y, otherwise N.
2013 The Extended Industry Standard Architecture (EISA) bus was
2014 developed as an open alternative to the IBM MicroChannel bus.
2016 The EISA bus provided some of the features of the IBM MicroChannel
2017 bus while maintaining backward compatibility with cards made for
2018 the older ISA bus. The EISA bus saw limited use between 1988 and
2019 1995 when it was made obsolete by the PCI bus.
2021 Say Y here if you are building a kernel for an EISA-based machine.
2025 source "drivers/eisa/Kconfig"
2030 MicroChannel Architecture is found in some IBM PS/2 machines and
2031 laptops. It is a bus system similar to PCI or ISA. See
2032 <file:Documentation/mca.txt> (and especially the web page given
2033 there) before attempting to build an MCA bus kernel.
2035 source "drivers/mca/Kconfig"
2038 tristate "NatSemi SCx200 support"
2040 This provides basic support for National Semiconductor's
2041 (now AMD's) Geode processors. The driver probes for the
2042 PCI-IDs of several on-chip devices, so its a good dependency
2043 for other scx200_* drivers.
2045 If compiled as a module, the driver is named scx200.
2047 config SCx200HR_TIMER
2048 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2049 depends on SCx200 && GENERIC_TIME
2052 This driver provides a clocksource built upon the on-chip
2053 27MHz high-resolution timer. Its also a workaround for
2054 NSC Geode SC-1100's buggy TSC, which loses time when the
2055 processor goes idle (as is done by the scheduler). The
2056 other workaround is idle=poll boot option.
2059 bool "One Laptop Per Child support"
2062 Add support for detecting the unique features of the OLPC
2069 depends on CPU_SUP_AMD && PCI
2071 source "drivers/pcmcia/Kconfig"
2073 source "drivers/pci/hotplug/Kconfig"
2078 menu "Executable file formats / Emulations"
2080 source "fs/Kconfig.binfmt"
2082 config IA32_EMULATION
2083 bool "IA32 Emulation"
2085 select COMPAT_BINFMT_ELF
2087 Include code to run 32-bit programs under a 64-bit kernel. You should
2088 likely turn this on, unless you're 100% sure that you don't have any
2089 32-bit programs left.
2092 tristate "IA32 a.out support"
2093 depends on IA32_EMULATION
2095 Support old a.out binaries in the 32bit emulation.
2099 depends on IA32_EMULATION
2101 config COMPAT_FOR_U64_ALIGNMENT
2105 config SYSVIPC_COMPAT
2107 depends on COMPAT && SYSVIPC
2112 config HAVE_ATOMIC_IOMAP
2116 source "net/Kconfig"
2118 source "drivers/Kconfig"
2120 source "drivers/firmware/Kconfig"
2124 source "arch/x86/Kconfig.debug"
2126 source "security/Kconfig"
2128 source "crypto/Kconfig"
2130 source "arch/x86/kvm/Kconfig"
2132 source "lib/Kconfig"
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