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
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_DYNAMIC_FTRACE
38 select HAVE_FUNCTION_TRACER
39 select HAVE_FUNCTION_GRAPH_TRACER
40 select HAVE_FUNCTION_GRAPH_FP_TEST
41 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
42 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
43 select HAVE_SYSCALL_TRACEPOINTS
46 select HAVE_ARCH_TRACEHOOK
47 select HAVE_GENERIC_DMA_COHERENT if X86_32
48 select HAVE_EFFICIENT_UNALIGNED_ACCESS
49 select USER_STACKTRACE_SUPPORT
50 select HAVE_REGS_AND_STACK_ACCESS_API
51 select HAVE_DMA_API_DEBUG
52 select HAVE_KERNEL_GZIP
53 select HAVE_KERNEL_BZIP2
54 select HAVE_KERNEL_LZMA
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
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
79 config GENERIC_CMOS_UPDATE
82 config CLOCKSOURCE_WATCHDOG
85 config GENERIC_CLOCKEVENTS
88 config GENERIC_CLOCKEVENTS_BROADCAST
90 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
92 config LOCKDEP_SUPPORT
95 config STACKTRACE_SUPPORT
98 config HAVE_LATENCYTOP_SUPPORT
110 config NEED_DMA_MAP_STATE
111 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
113 config NEED_SG_DMA_LENGTH
116 config GENERIC_ISA_DMA
125 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
127 config GENERIC_BUG_RELATIVE_POINTERS
130 config GENERIC_HWEIGHT
136 config ARCH_MAY_HAVE_PC_FDC
139 config RWSEM_GENERIC_SPINLOCK
142 config RWSEM_XCHGADD_ALGORITHM
145 config ARCH_HAS_CPU_IDLE_WAIT
148 config GENERIC_CALIBRATE_DELAY
151 config GENERIC_TIME_VSYSCALL
155 config ARCH_HAS_CPU_RELAX
158 config ARCH_HAS_DEFAULT_IDLE
161 config ARCH_HAS_CACHE_LINE_SIZE
164 config HAVE_SETUP_PER_CPU_AREA
167 config NEED_PER_CPU_EMBED_FIRST_CHUNK
170 config NEED_PER_CPU_PAGE_FIRST_CHUNK
173 config HAVE_CPUMASK_OF_CPU_MAP
176 config ARCH_HIBERNATION_POSSIBLE
179 config ARCH_SUSPEND_POSSIBLE
186 config ARCH_POPULATES_NODE_MAP
193 config ARCH_SUPPORTS_OPTIMIZED_INLINING
196 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
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.
593 This option adds a kernel parameter 'memtest', which allows memtest
595 memtest=0, mean disabled; -- default
596 memtest=1, mean do 1 test pattern;
598 memtest=4, mean do 4 test patterns.
599 If you are unsure how to answer this question, answer N.
601 config X86_SUMMIT_NUMA
603 depends on X86_32 && NUMA && X86_32_NON_STANDARD
605 config X86_CYCLONE_TIMER
607 depends on X86_32_NON_STANDARD
609 source "arch/x86/Kconfig.cpu"
613 prompt "HPET Timer Support" if X86_32
615 Use the IA-PC HPET (High Precision Event Timer) to manage
616 time in preference to the PIT and RTC, if a HPET is
618 HPET is the next generation timer replacing legacy 8254s.
619 The HPET provides a stable time base on SMP
620 systems, unlike the TSC, but it is more expensive to access,
621 as it is off-chip. You can find the HPET spec at
622 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
624 You can safely choose Y here. However, HPET will only be
625 activated if the platform and the BIOS support this feature.
626 Otherwise the 8254 will be used for timing services.
628 Choose N to continue using the legacy 8254 timer.
630 config HPET_EMULATE_RTC
632 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
636 prompt "Langwell APB Timer Support" if X86_MRST
638 APB timer is the replacement for 8254, HPET on X86 MID platforms.
639 The APBT provides a stable time base on SMP
640 systems, unlike the TSC, but it is more expensive to access,
641 as it is off-chip. APB timers are always running regardless of CPU
642 C states, they are used as per CPU clockevent device when possible.
644 # Mark as embedded because too many people got it wrong.
645 # The code disables itself when not needed.
648 bool "Enable DMI scanning" if EMBEDDED
650 Enabled scanning of DMI to identify machine quirks. Say Y
651 here unless you have verified that your setup is not
652 affected by entries in the DMI blacklist. Required by PNP
656 bool "GART IOMMU support" if EMBEDDED
659 depends on X86_64 && PCI && K8_NB
661 Support for full DMA access of devices with 32bit memory access only
662 on systems with more than 3GB. This is usually needed for USB,
663 sound, many IDE/SATA chipsets and some other devices.
664 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
665 based hardware IOMMU and a software bounce buffer based IOMMU used
666 on Intel systems and as fallback.
667 The code is only active when needed (enough memory and limited
668 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
672 bool "IBM Calgary IOMMU support"
674 depends on X86_64 && PCI && EXPERIMENTAL
676 Support for hardware IOMMUs in IBM's xSeries x366 and x460
677 systems. Needed to run systems with more than 3GB of memory
678 properly with 32-bit PCI devices that do not support DAC
679 (Double Address Cycle). Calgary also supports bus level
680 isolation, where all DMAs pass through the IOMMU. This
681 prevents them from going anywhere except their intended
682 destination. This catches hard-to-find kernel bugs and
683 mis-behaving drivers and devices that do not use the DMA-API
684 properly to set up their DMA buffers. The IOMMU can be
685 turned off at boot time with the iommu=off parameter.
686 Normally the kernel will make the right choice by itself.
689 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
691 prompt "Should Calgary be enabled by default?"
692 depends on CALGARY_IOMMU
694 Should Calgary be enabled by default? if you choose 'y', Calgary
695 will be used (if it exists). If you choose 'n', Calgary will not be
696 used even if it exists. If you choose 'n' and would like to use
697 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
701 bool "AMD IOMMU support"
704 depends on X86_64 && PCI && ACPI
706 With this option you can enable support for AMD IOMMU hardware in
707 your system. An IOMMU is a hardware component which provides
708 remapping of DMA memory accesses from devices. With an AMD IOMMU you
709 can isolate the the DMA memory of different devices and protect the
710 system from misbehaving device drivers or hardware.
712 You can find out if your system has an AMD IOMMU if you look into
713 your BIOS for an option to enable it or if you have an IVRS ACPI
716 config AMD_IOMMU_STATS
717 bool "Export AMD IOMMU statistics to debugfs"
721 This option enables code in the AMD IOMMU driver to collect various
722 statistics about whats happening in the driver and exports that
723 information to userspace via debugfs.
726 # need this always selected by IOMMU for the VIA workaround
730 Support for software bounce buffers used on x86-64 systems
731 which don't have a hardware IOMMU (e.g. the current generation
732 of Intel's x86-64 CPUs). Using this PCI devices which can only
733 access 32-bits of memory can be used on systems with more than
734 3 GB of memory. If unsure, say Y.
737 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
740 def_bool (AMD_IOMMU || DMAR)
743 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
744 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
745 select CPUMASK_OFFSTACK
747 Configure maximum number of CPUS and NUMA Nodes for this architecture.
751 int "Maximum number of CPUs" if SMP && !MAXSMP
752 range 2 8 if SMP && X86_32 && !X86_BIGSMP
753 range 2 512 if SMP && !MAXSMP
755 default "4096" if MAXSMP
756 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
759 This allows you to specify the maximum number of CPUs which this
760 kernel will support. The maximum supported value is 512 and the
761 minimum value which makes sense is 2.
763 This is purely to save memory - each supported CPU adds
764 approximately eight kilobytes to the kernel image.
767 bool "SMT (Hyperthreading) scheduler support"
770 SMT scheduler support improves the CPU scheduler's decision making
771 when dealing with Intel Pentium 4 chips with HyperThreading at a
772 cost of slightly increased overhead in some places. If unsure say
777 prompt "Multi-core scheduler support"
780 Multi-core scheduler support improves the CPU scheduler's decision
781 making when dealing with multi-core CPU chips at a cost of slightly
782 increased overhead in some places. If unsure say N here.
784 source "kernel/Kconfig.preempt"
787 bool "Local APIC support on uniprocessors"
788 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
790 A local APIC (Advanced Programmable Interrupt Controller) is an
791 integrated interrupt controller in the CPU. If you have a single-CPU
792 system which has a processor with a local APIC, you can say Y here to
793 enable and use it. If you say Y here even though your machine doesn't
794 have a local APIC, then the kernel will still run with no slowdown at
795 all. The local APIC supports CPU-generated self-interrupts (timer,
796 performance counters), and the NMI watchdog which detects hard
800 bool "IO-APIC support on uniprocessors"
801 depends on X86_UP_APIC
803 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
804 SMP-capable replacement for PC-style interrupt controllers. Most
805 SMP systems and many recent uniprocessor systems have one.
807 If you have a single-CPU system with an IO-APIC, you can say Y here
808 to use it. If you say Y here even though your machine doesn't have
809 an IO-APIC, then the kernel will still run with no slowdown at all.
811 config X86_LOCAL_APIC
813 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
817 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
819 config X86_VISWS_APIC
821 depends on X86_32 && X86_VISWS
823 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
824 bool "Reroute for broken boot IRQs"
825 depends on X86_IO_APIC
827 This option enables a workaround that fixes a source of
828 spurious interrupts. This is recommended when threaded
829 interrupt handling is used on systems where the generation of
830 superfluous "boot interrupts" cannot be disabled.
832 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
833 entry in the chipset's IO-APIC is masked (as, e.g. the RT
834 kernel does during interrupt handling). On chipsets where this
835 boot IRQ generation cannot be disabled, this workaround keeps
836 the original IRQ line masked so that only the equivalent "boot
837 IRQ" is delivered to the CPUs. The workaround also tells the
838 kernel to set up the IRQ handler on the boot IRQ line. In this
839 way only one interrupt is delivered to the kernel. Otherwise
840 the spurious second interrupt may cause the kernel to bring
841 down (vital) interrupt lines.
843 Only affects "broken" chipsets. Interrupt sharing may be
844 increased on these systems.
847 bool "Machine Check / overheating reporting"
849 Machine Check support allows the processor to notify the
850 kernel if it detects a problem (e.g. overheating, data corruption).
851 The action the kernel takes depends on the severity of the problem,
852 ranging from warning messages to halting the machine.
856 prompt "Intel MCE features"
857 depends on X86_MCE && X86_LOCAL_APIC
859 Additional support for intel specific MCE features such as
864 prompt "AMD MCE features"
865 depends on X86_MCE && X86_LOCAL_APIC
867 Additional support for AMD specific MCE features such as
868 the DRAM Error Threshold.
870 config X86_ANCIENT_MCE
871 bool "Support for old Pentium 5 / WinChip machine checks"
872 depends on X86_32 && X86_MCE
874 Include support for machine check handling on old Pentium 5 or WinChip
875 systems. These typically need to be enabled explicitely on the command
878 config X86_MCE_THRESHOLD
879 depends on X86_MCE_AMD || X86_MCE_INTEL
882 config X86_MCE_INJECT
884 tristate "Machine check injector support"
886 Provide support for injecting machine checks for testing purposes.
887 If you don't know what a machine check is and you don't do kernel
888 QA it is safe to say n.
890 config X86_THERMAL_VECTOR
892 depends on X86_MCE_INTEL
895 bool "Enable VM86 support" if EMBEDDED
899 This option is required by programs like DOSEMU to run 16-bit legacy
900 code on X86 processors. It also may be needed by software like
901 XFree86 to initialize some video cards via BIOS. Disabling this
902 option saves about 6k.
905 tristate "Toshiba Laptop support"
908 This adds a driver to safely access the System Management Mode of
909 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
910 not work on models with a Phoenix BIOS. The System Management Mode
911 is used to set the BIOS and power saving options on Toshiba portables.
913 For information on utilities to make use of this driver see the
914 Toshiba Linux utilities web site at:
915 <http://www.buzzard.org.uk/toshiba/>.
917 Say Y if you intend to run this kernel on a Toshiba portable.
921 tristate "Dell laptop support"
923 This adds a driver to safely access the System Management Mode
924 of the CPU on the Dell Inspiron 8000. The System Management Mode
925 is used to read cpu temperature and cooling fan status and to
926 control the fans on the I8K portables.
928 This driver has been tested only on the Inspiron 8000 but it may
929 also work with other Dell laptops. You can force loading on other
930 models by passing the parameter `force=1' to the module. Use at
933 For information on utilities to make use of this driver see the
934 I8K Linux utilities web site at:
935 <http://people.debian.org/~dz/i8k/>
937 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
940 config X86_REBOOTFIXUPS
941 bool "Enable X86 board specific fixups for reboot"
944 This enables chipset and/or board specific fixups to be done
945 in order to get reboot to work correctly. This is only needed on
946 some combinations of hardware and BIOS. The symptom, for which
947 this config is intended, is when reboot ends with a stalled/hung
950 Currently, the only fixup is for the Geode machines using
951 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
953 Say Y if you want to enable the fixup. Currently, it's safe to
954 enable this option even if you don't need it.
958 tristate "/dev/cpu/microcode - microcode support"
961 If you say Y here, you will be able to update the microcode on
962 certain Intel and AMD processors. The Intel support is for the
963 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
964 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
965 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
966 You will obviously need the actual microcode binary data itself
967 which is not shipped with the Linux kernel.
969 This option selects the general module only, you need to select
970 at least one vendor specific module as well.
972 To compile this driver as a module, choose M here: the
973 module will be called microcode.
975 config MICROCODE_INTEL
976 bool "Intel microcode patch loading support"
981 This options enables microcode patch loading support for Intel
984 For latest news and information on obtaining all the required
985 Intel ingredients for this driver, check:
986 <http://www.urbanmyth.org/microcode/>.
989 bool "AMD microcode patch loading support"
993 If you select this option, microcode patch loading support for AMD
994 processors will be enabled.
996 config MICROCODE_OLD_INTERFACE
1001 tristate "/dev/cpu/*/msr - Model-specific register support"
1003 This device gives privileged processes access to the x86
1004 Model-Specific Registers (MSRs). It is a character device with
1005 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1006 MSR accesses are directed to a specific CPU on multi-processor
1010 tristate "/dev/cpu/*/cpuid - CPU information support"
1012 This device gives processes access to the x86 CPUID instruction to
1013 be executed on a specific processor. It is a character device
1014 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1018 prompt "High Memory Support"
1019 default HIGHMEM64G if X86_NUMAQ
1025 depends on !X86_NUMAQ
1027 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1028 However, the address space of 32-bit x86 processors is only 4
1029 Gigabytes large. That means that, if you have a large amount of
1030 physical memory, not all of it can be "permanently mapped" by the
1031 kernel. The physical memory that's not permanently mapped is called
1034 If you are compiling a kernel which will never run on a machine with
1035 more than 1 Gigabyte total physical RAM, answer "off" here (default
1036 choice and suitable for most users). This will result in a "3GB/1GB"
1037 split: 3GB are mapped so that each process sees a 3GB virtual memory
1038 space and the remaining part of the 4GB virtual memory space is used
1039 by the kernel to permanently map as much physical memory as
1042 If the machine has between 1 and 4 Gigabytes physical RAM, then
1045 If more than 4 Gigabytes is used then answer "64GB" here. This
1046 selection turns Intel PAE (Physical Address Extension) mode on.
1047 PAE implements 3-level paging on IA32 processors. PAE is fully
1048 supported by Linux, PAE mode is implemented on all recent Intel
1049 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1050 then the kernel will not boot on CPUs that don't support PAE!
1052 The actual amount of total physical memory will either be
1053 auto detected or can be forced by using a kernel command line option
1054 such as "mem=256M". (Try "man bootparam" or see the documentation of
1055 your boot loader (lilo or loadlin) about how to pass options to the
1056 kernel at boot time.)
1058 If unsure, say "off".
1062 depends on !X86_NUMAQ
1064 Select this if you have a 32-bit processor and between 1 and 4
1065 gigabytes of physical RAM.
1069 depends on !M386 && !M486
1072 Select this if you have a 32-bit processor and more than 4
1073 gigabytes of physical RAM.
1078 depends on EXPERIMENTAL
1079 prompt "Memory split" if EMBEDDED
1083 Select the desired split between kernel and user memory.
1085 If the address range available to the kernel is less than the
1086 physical memory installed, the remaining memory will be available
1087 as "high memory". Accessing high memory is a little more costly
1088 than low memory, as it needs to be mapped into the kernel first.
1089 Note that increasing the kernel address space limits the range
1090 available to user programs, making the address space there
1091 tighter. Selecting anything other than the default 3G/1G split
1092 will also likely make your kernel incompatible with binary-only
1095 If you are not absolutely sure what you are doing, leave this
1099 bool "3G/1G user/kernel split"
1100 config VMSPLIT_3G_OPT
1102 bool "3G/1G user/kernel split (for full 1G low memory)"
1104 bool "2G/2G user/kernel split"
1105 config VMSPLIT_2G_OPT
1107 bool "2G/2G user/kernel split (for full 2G low memory)"
1109 bool "1G/3G user/kernel split"
1114 default 0xB0000000 if VMSPLIT_3G_OPT
1115 default 0x80000000 if VMSPLIT_2G
1116 default 0x78000000 if VMSPLIT_2G_OPT
1117 default 0x40000000 if VMSPLIT_1G
1123 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1126 bool "PAE (Physical Address Extension) Support"
1127 depends on X86_32 && !HIGHMEM4G
1129 PAE is required for NX support, and furthermore enables
1130 larger swapspace support for non-overcommit purposes. It
1131 has the cost of more pagetable lookup overhead, and also
1132 consumes more pagetable space per process.
1134 config ARCH_PHYS_ADDR_T_64BIT
1135 def_bool X86_64 || X86_PAE
1137 config DIRECT_GBPAGES
1138 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1142 Allow the kernel linear mapping to use 1GB pages on CPUs that
1143 support it. This can improve the kernel's performance a tiny bit by
1144 reducing TLB pressure. If in doubt, say "Y".
1146 # Common NUMA Features
1148 bool "Numa Memory Allocation and Scheduler Support"
1150 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1151 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1153 Enable NUMA (Non Uniform Memory Access) support.
1155 The kernel will try to allocate memory used by a CPU on the
1156 local memory controller of the CPU and add some more
1157 NUMA awareness to the kernel.
1159 For 64-bit this is recommended if the system is Intel Core i7
1160 (or later), AMD Opteron, or EM64T NUMA.
1162 For 32-bit this is only needed on (rare) 32-bit-only platforms
1163 that support NUMA topologies, such as NUMAQ / Summit, or if you
1164 boot a 32-bit kernel on a 64-bit NUMA platform.
1166 Otherwise, you should say N.
1168 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1169 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1173 prompt "Old style AMD Opteron NUMA detection"
1174 depends on X86_64 && NUMA && PCI
1176 Enable K8 NUMA node topology detection. You should say Y here if
1177 you have a multi processor AMD K8 system. This uses an old
1178 method to read the NUMA configuration directly from the builtin
1179 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1180 instead, which also takes priority if both are compiled in.
1182 config X86_64_ACPI_NUMA
1184 prompt "ACPI NUMA detection"
1185 depends on X86_64 && NUMA && ACPI && PCI
1188 Enable ACPI SRAT based node topology detection.
1190 # Some NUMA nodes have memory ranges that span
1191 # other nodes. Even though a pfn is valid and
1192 # between a node's start and end pfns, it may not
1193 # reside on that node. See memmap_init_zone()
1195 config NODES_SPAN_OTHER_NODES
1197 depends on X86_64_ACPI_NUMA
1200 bool "NUMA emulation"
1201 depends on X86_64 && NUMA
1203 Enable NUMA emulation. A flat machine will be split
1204 into virtual nodes when booted with "numa=fake=N", where N is the
1205 number of nodes. This is only useful for debugging.
1208 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1210 default "10" if MAXSMP
1211 default "6" if X86_64
1212 default "4" if X86_NUMAQ
1214 depends on NEED_MULTIPLE_NODES
1216 Specify the maximum number of NUMA Nodes available on the target
1217 system. Increases memory reserved to accommodate various tables.
1219 config HAVE_ARCH_BOOTMEM
1221 depends on X86_32 && NUMA
1223 config ARCH_HAVE_MEMORY_PRESENT
1225 depends on X86_32 && DISCONTIGMEM
1227 config NEED_NODE_MEMMAP_SIZE
1229 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1231 config HAVE_ARCH_ALLOC_REMAP
1233 depends on X86_32 && NUMA
1235 config ARCH_FLATMEM_ENABLE
1237 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1239 config ARCH_DISCONTIGMEM_ENABLE
1241 depends on NUMA && X86_32
1243 config ARCH_DISCONTIGMEM_DEFAULT
1245 depends on NUMA && X86_32
1247 config ARCH_PROC_KCORE_TEXT
1249 depends on X86_64 && PROC_KCORE
1251 config ARCH_SPARSEMEM_DEFAULT
1255 config ARCH_SPARSEMEM_ENABLE
1257 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1258 select SPARSEMEM_STATIC if X86_32
1259 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1261 config ARCH_SELECT_MEMORY_MODEL
1263 depends on ARCH_SPARSEMEM_ENABLE
1265 config ARCH_MEMORY_PROBE
1267 depends on MEMORY_HOTPLUG
1269 config ILLEGAL_POINTER_VALUE
1272 default 0xdead000000000000 if X86_64
1277 bool "Allocate 3rd-level pagetables from highmem"
1280 The VM uses one page table entry for each page of physical memory.
1281 For systems with a lot of RAM, this can be wasteful of precious
1282 low memory. Setting this option will put user-space page table
1283 entries in high memory.
1285 config X86_CHECK_BIOS_CORRUPTION
1286 bool "Check for low memory corruption"
1288 Periodically check for memory corruption in low memory, which
1289 is suspected to be caused by BIOS. Even when enabled in the
1290 configuration, it is disabled at runtime. Enable it by
1291 setting "memory_corruption_check=1" on the kernel command
1292 line. By default it scans the low 64k of memory every 60
1293 seconds; see the memory_corruption_check_size and
1294 memory_corruption_check_period parameters in
1295 Documentation/kernel-parameters.txt to adjust this.
1297 When enabled with the default parameters, this option has
1298 almost no overhead, as it reserves a relatively small amount
1299 of memory and scans it infrequently. It both detects corruption
1300 and prevents it from affecting the running system.
1302 It is, however, intended as a diagnostic tool; if repeatable
1303 BIOS-originated corruption always affects the same memory,
1304 you can use memmap= to prevent the kernel from using that
1307 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1308 bool "Set the default setting of memory_corruption_check"
1309 depends on X86_CHECK_BIOS_CORRUPTION
1312 Set whether the default state of memory_corruption_check is
1315 config X86_RESERVE_LOW_64K
1316 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1319 Reserve the first 64K of physical RAM on BIOSes that are known
1320 to potentially corrupt that memory range. A numbers of BIOSes are
1321 known to utilize this area during suspend/resume, so it must not
1322 be used by the kernel.
1324 Set this to N if you are absolutely sure that you trust the BIOS
1325 to get all its memory reservations and usages right.
1327 If you have doubts about the BIOS (e.g. suspend/resume does not
1328 work or there's kernel crashes after certain hardware hotplug
1329 events) and it's not AMI or Phoenix, then you might want to enable
1330 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1331 corruption patterns.
1335 config MATH_EMULATION
1337 prompt "Math emulation" if X86_32
1339 Linux can emulate a math coprocessor (used for floating point
1340 operations) if you don't have one. 486DX and Pentium processors have
1341 a math coprocessor built in, 486SX and 386 do not, unless you added
1342 a 487DX or 387, respectively. (The messages during boot time can
1343 give you some hints here ["man dmesg"].) Everyone needs either a
1344 coprocessor or this emulation.
1346 If you don't have a math coprocessor, you need to say Y here; if you
1347 say Y here even though you have a coprocessor, the coprocessor will
1348 be used nevertheless. (This behavior can be changed with the kernel
1349 command line option "no387", which comes handy if your coprocessor
1350 is broken. Try "man bootparam" or see the documentation of your boot
1351 loader (lilo or loadlin) about how to pass options to the kernel at
1352 boot time.) This means that it is a good idea to say Y here if you
1353 intend to use this kernel on different machines.
1355 More information about the internals of the Linux math coprocessor
1356 emulation can be found in <file:arch/x86/math-emu/README>.
1358 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1359 kernel, it won't hurt.
1363 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1365 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1366 the Memory Type Range Registers (MTRRs) may be used to control
1367 processor access to memory ranges. This is most useful if you have
1368 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1369 allows bus write transfers to be combined into a larger transfer
1370 before bursting over the PCI/AGP bus. This can increase performance
1371 of image write operations 2.5 times or more. Saying Y here creates a
1372 /proc/mtrr file which may be used to manipulate your processor's
1373 MTRRs. Typically the X server should use this.
1375 This code has a reasonably generic interface so that similar
1376 control registers on other processors can be easily supported
1379 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1380 Registers (ARRs) which provide a similar functionality to MTRRs. For
1381 these, the ARRs are used to emulate the MTRRs.
1382 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1383 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1384 write-combining. All of these processors are supported by this code
1385 and it makes sense to say Y here if you have one of them.
1387 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1388 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1389 can lead to all sorts of problems, so it's good to say Y here.
1391 You can safely say Y even if your machine doesn't have MTRRs, you'll
1392 just add about 9 KB to your kernel.
1394 See <file:Documentation/x86/mtrr.txt> for more information.
1396 config MTRR_SANITIZER
1398 prompt "MTRR cleanup support"
1401 Convert MTRR layout from continuous to discrete, so X drivers can
1402 add writeback entries.
1404 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1405 The largest mtrr entry size for a continuous block can be set with
1410 config MTRR_SANITIZER_ENABLE_DEFAULT
1411 int "MTRR cleanup enable value (0-1)"
1414 depends on MTRR_SANITIZER
1416 Enable mtrr cleanup default value
1418 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1419 int "MTRR cleanup spare reg num (0-7)"
1422 depends on MTRR_SANITIZER
1424 mtrr cleanup spare entries default, it can be changed via
1425 mtrr_spare_reg_nr=N on the kernel command line.
1429 prompt "x86 PAT support" if EMBEDDED
1432 Use PAT attributes to setup page level cache control.
1434 PATs are the modern equivalents of MTRRs and are much more
1435 flexible than MTRRs.
1437 Say N here if you see bootup problems (boot crash, boot hang,
1438 spontaneous reboots) or a non-working video driver.
1442 config ARCH_USES_PG_UNCACHED
1447 bool "EFI runtime service support"
1450 This enables the kernel to use EFI runtime services that are
1451 available (such as the EFI variable services).
1453 This option is only useful on systems that have EFI firmware.
1454 In addition, you should use the latest ELILO loader available
1455 at <http://elilo.sourceforge.net> in order to take advantage
1456 of EFI runtime services. However, even with this option, the
1457 resultant kernel should continue to boot on existing non-EFI
1462 prompt "Enable seccomp to safely compute untrusted bytecode"
1464 This kernel feature is useful for number crunching applications
1465 that may need to compute untrusted bytecode during their
1466 execution. By using pipes or other transports made available to
1467 the process as file descriptors supporting the read/write
1468 syscalls, it's possible to isolate those applications in
1469 their own address space using seccomp. Once seccomp is
1470 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1471 and the task is only allowed to execute a few safe syscalls
1472 defined by each seccomp mode.
1474 If unsure, say Y. Only embedded should say N here.
1476 config CC_STACKPROTECTOR
1477 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1479 This option turns on the -fstack-protector GCC feature. This
1480 feature puts, at the beginning of functions, a canary value on
1481 the stack just before the return address, and validates
1482 the value just before actually returning. Stack based buffer
1483 overflows (that need to overwrite this return address) now also
1484 overwrite the canary, which gets detected and the attack is then
1485 neutralized via a kernel panic.
1487 This feature requires gcc version 4.2 or above, or a distribution
1488 gcc with the feature backported. Older versions are automatically
1489 detected and for those versions, this configuration option is
1490 ignored. (and a warning is printed during bootup)
1492 source kernel/Kconfig.hz
1495 bool "kexec system call"
1497 kexec is a system call that implements the ability to shutdown your
1498 current kernel, and to start another kernel. It is like a reboot
1499 but it is independent of the system firmware. And like a reboot
1500 you can start any kernel with it, not just Linux.
1502 The name comes from the similarity to the exec system call.
1504 It is an ongoing process to be certain the hardware in a machine
1505 is properly shutdown, so do not be surprised if this code does not
1506 initially work for you. It may help to enable device hotplugging
1507 support. As of this writing the exact hardware interface is
1508 strongly in flux, so no good recommendation can be made.
1511 bool "kernel crash dumps"
1512 depends on X86_64 || (X86_32 && HIGHMEM)
1514 Generate crash dump after being started by kexec.
1515 This should be normally only set in special crash dump kernels
1516 which are loaded in the main kernel with kexec-tools into
1517 a specially reserved region and then later executed after
1518 a crash by kdump/kexec. The crash dump kernel must be compiled
1519 to a memory address not used by the main kernel or BIOS using
1520 PHYSICAL_START, or it must be built as a relocatable image
1521 (CONFIG_RELOCATABLE=y).
1522 For more details see Documentation/kdump/kdump.txt
1525 bool "kexec jump (EXPERIMENTAL)"
1526 depends on EXPERIMENTAL
1527 depends on KEXEC && HIBERNATION
1529 Jump between original kernel and kexeced kernel and invoke
1530 code in physical address mode via KEXEC
1532 config PHYSICAL_START
1533 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1536 This gives the physical address where the kernel is loaded.
1538 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1539 bzImage will decompress itself to above physical address and
1540 run from there. Otherwise, bzImage will run from the address where
1541 it has been loaded by the boot loader and will ignore above physical
1544 In normal kdump cases one does not have to set/change this option
1545 as now bzImage can be compiled as a completely relocatable image
1546 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1547 address. This option is mainly useful for the folks who don't want
1548 to use a bzImage for capturing the crash dump and want to use a
1549 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1550 to be specifically compiled to run from a specific memory area
1551 (normally a reserved region) and this option comes handy.
1553 So if you are using bzImage for capturing the crash dump,
1554 leave the value here unchanged to 0x1000000 and set
1555 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1556 for capturing the crash dump change this value to start of
1557 the reserved region. In other words, it can be set based on
1558 the "X" value as specified in the "crashkernel=YM@XM"
1559 command line boot parameter passed to the panic-ed
1560 kernel. Please take a look at Documentation/kdump/kdump.txt
1561 for more details about crash dumps.
1563 Usage of bzImage for capturing the crash dump is recommended as
1564 one does not have to build two kernels. Same kernel can be used
1565 as production kernel and capture kernel. Above option should have
1566 gone away after relocatable bzImage support is introduced. But it
1567 is present because there are users out there who continue to use
1568 vmlinux for dump capture. This option should go away down the
1571 Don't change this unless you know what you are doing.
1574 bool "Build a relocatable kernel"
1577 This builds a kernel image that retains relocation information
1578 so it can be loaded someplace besides the default 1MB.
1579 The relocations tend to make the kernel binary about 10% larger,
1580 but are discarded at runtime.
1582 One use is for the kexec on panic case where the recovery kernel
1583 must live at a different physical address than the primary
1586 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1587 it has been loaded at and the compile time physical address
1588 (CONFIG_PHYSICAL_START) is ignored.
1590 # Relocation on x86-32 needs some additional build support
1591 config X86_NEED_RELOCS
1593 depends on X86_32 && RELOCATABLE
1595 config PHYSICAL_ALIGN
1596 hex "Alignment value to which kernel should be aligned" if X86_32
1598 range 0x2000 0x1000000
1600 This value puts the alignment restrictions on physical address
1601 where kernel is loaded and run from. Kernel is compiled for an
1602 address which meets above alignment restriction.
1604 If bootloader loads the kernel at a non-aligned address and
1605 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1606 address aligned to above value and run from there.
1608 If bootloader loads the kernel at a non-aligned address and
1609 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1610 load address and decompress itself to the address it has been
1611 compiled for and run from there. The address for which kernel is
1612 compiled already meets above alignment restrictions. Hence the
1613 end result is that kernel runs from a physical address meeting
1614 above alignment restrictions.
1616 Don't change this unless you know what you are doing.
1619 bool "Support for hot-pluggable CPUs"
1620 depends on SMP && HOTPLUG
1622 Say Y here to allow turning CPUs off and on. CPUs can be
1623 controlled through /sys/devices/system/cpu.
1624 ( Note: power management support will enable this option
1625 automatically on SMP systems. )
1626 Say N if you want to disable CPU hotplug.
1630 prompt "Compat VDSO support"
1631 depends on X86_32 || IA32_EMULATION
1633 Map the 32-bit VDSO to the predictable old-style address too.
1635 Say N here if you are running a sufficiently recent glibc
1636 version (2.3.3 or later), to remove the high-mapped
1637 VDSO mapping and to exclusively use the randomized VDSO.
1642 bool "Built-in kernel command line"
1644 Allow for specifying boot arguments to the kernel at
1645 build time. On some systems (e.g. embedded ones), it is
1646 necessary or convenient to provide some or all of the
1647 kernel boot arguments with the kernel itself (that is,
1648 to not rely on the boot loader to provide them.)
1650 To compile command line arguments into the kernel,
1651 set this option to 'Y', then fill in the
1652 the boot arguments in CONFIG_CMDLINE.
1654 Systems with fully functional boot loaders (i.e. non-embedded)
1655 should leave this option set to 'N'.
1658 string "Built-in kernel command string"
1659 depends on CMDLINE_BOOL
1662 Enter arguments here that should be compiled into the kernel
1663 image and used at boot time. If the boot loader provides a
1664 command line at boot time, it is appended to this string to
1665 form the full kernel command line, when the system boots.
1667 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1668 change this behavior.
1670 In most cases, the command line (whether built-in or provided
1671 by the boot loader) should specify the device for the root
1674 config CMDLINE_OVERRIDE
1675 bool "Built-in command line overrides boot loader arguments"
1676 depends on CMDLINE_BOOL
1678 Set this option to 'Y' to have the kernel ignore the boot loader
1679 command line, and use ONLY the built-in command line.
1681 This is used to work around broken boot loaders. This should
1682 be set to 'N' under normal conditions.
1686 config ARCH_ENABLE_MEMORY_HOTPLUG
1688 depends on X86_64 || (X86_32 && HIGHMEM)
1690 config ARCH_ENABLE_MEMORY_HOTREMOVE
1692 depends on MEMORY_HOTPLUG
1694 config HAVE_ARCH_EARLY_PFN_TO_NID
1698 config USE_PERCPU_NUMA_NODE_ID
1702 menu "Power management and ACPI options"
1704 config ARCH_HIBERNATION_HEADER
1706 depends on X86_64 && HIBERNATION
1708 source "kernel/power/Kconfig"
1710 source "drivers/acpi/Kconfig"
1712 source "drivers/sfi/Kconfig"
1716 depends on APM || APM_MODULE
1719 tristate "APM (Advanced Power Management) BIOS support"
1720 depends on X86_32 && PM_SLEEP
1722 APM is a BIOS specification for saving power using several different
1723 techniques. This is mostly useful for battery powered laptops with
1724 APM compliant BIOSes. If you say Y here, the system time will be
1725 reset after a RESUME operation, the /proc/apm device will provide
1726 battery status information, and user-space programs will receive
1727 notification of APM "events" (e.g. battery status change).
1729 If you select "Y" here, you can disable actual use of the APM
1730 BIOS by passing the "apm=off" option to the kernel at boot time.
1732 Note that the APM support is almost completely disabled for
1733 machines with more than one CPU.
1735 In order to use APM, you will need supporting software. For location
1736 and more information, read <file:Documentation/power/pm.txt> and the
1737 Battery Powered Linux mini-HOWTO, available from
1738 <http://www.tldp.org/docs.html#howto>.
1740 This driver does not spin down disk drives (see the hdparm(8)
1741 manpage ("man 8 hdparm") for that), and it doesn't turn off
1742 VESA-compliant "green" monitors.
1744 This driver does not support the TI 4000M TravelMate and the ACER
1745 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1746 desktop machines also don't have compliant BIOSes, and this driver
1747 may cause those machines to panic during the boot phase.
1749 Generally, if you don't have a battery in your machine, there isn't
1750 much point in using this driver and you should say N. If you get
1751 random kernel OOPSes or reboots that don't seem to be related to
1752 anything, try disabling/enabling this option (or disabling/enabling
1755 Some other things you should try when experiencing seemingly random,
1758 1) make sure that you have enough swap space and that it is
1760 2) pass the "no-hlt" option to the kernel
1761 3) switch on floating point emulation in the kernel and pass
1762 the "no387" option to the kernel
1763 4) pass the "floppy=nodma" option to the kernel
1764 5) pass the "mem=4M" option to the kernel (thereby disabling
1765 all but the first 4 MB of RAM)
1766 6) make sure that the CPU is not over clocked.
1767 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1768 8) disable the cache from your BIOS settings
1769 9) install a fan for the video card or exchange video RAM
1770 10) install a better fan for the CPU
1771 11) exchange RAM chips
1772 12) exchange the motherboard.
1774 To compile this driver as a module, choose M here: the
1775 module will be called apm.
1779 config APM_IGNORE_USER_SUSPEND
1780 bool "Ignore USER SUSPEND"
1782 This option will ignore USER SUSPEND requests. On machines with a
1783 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1784 series notebooks, it is necessary to say Y because of a BIOS bug.
1786 config APM_DO_ENABLE
1787 bool "Enable PM at boot time"
1789 Enable APM features at boot time. From page 36 of the APM BIOS
1790 specification: "When disabled, the APM BIOS does not automatically
1791 power manage devices, enter the Standby State, enter the Suspend
1792 State, or take power saving steps in response to CPU Idle calls."
1793 This driver will make CPU Idle calls when Linux is idle (unless this
1794 feature is turned off -- see "Do CPU IDLE calls", below). This
1795 should always save battery power, but more complicated APM features
1796 will be dependent on your BIOS implementation. You may need to turn
1797 this option off if your computer hangs at boot time when using APM
1798 support, or if it beeps continuously instead of suspending. Turn
1799 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1800 T400CDT. This is off by default since most machines do fine without
1804 bool "Make CPU Idle calls when idle"
1806 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1807 On some machines, this can activate improved power savings, such as
1808 a slowed CPU clock rate, when the machine is idle. These idle calls
1809 are made after the idle loop has run for some length of time (e.g.,
1810 333 mS). On some machines, this will cause a hang at boot time or
1811 whenever the CPU becomes idle. (On machines with more than one CPU,
1812 this option does nothing.)
1814 config APM_DISPLAY_BLANK
1815 bool "Enable console blanking using APM"
1817 Enable console blanking using the APM. Some laptops can use this to
1818 turn off the LCD backlight when the screen blanker of the Linux
1819 virtual console blanks the screen. Note that this is only used by
1820 the virtual console screen blanker, and won't turn off the backlight
1821 when using the X Window system. This also doesn't have anything to
1822 do with your VESA-compliant power-saving monitor. Further, this
1823 option doesn't work for all laptops -- it might not turn off your
1824 backlight at all, or it might print a lot of errors to the console,
1825 especially if you are using gpm.
1827 config APM_ALLOW_INTS
1828 bool "Allow interrupts during APM BIOS calls"
1830 Normally we disable external interrupts while we are making calls to
1831 the APM BIOS as a measure to lessen the effects of a badly behaving
1832 BIOS implementation. The BIOS should reenable interrupts if it
1833 needs to. Unfortunately, some BIOSes do not -- especially those in
1834 many of the newer IBM Thinkpads. If you experience hangs when you
1835 suspend, try setting this to Y. Otherwise, say N.
1839 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1841 source "drivers/cpuidle/Kconfig"
1843 source "drivers/idle/Kconfig"
1848 menu "Bus options (PCI etc.)"
1853 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1855 Find out whether you have a PCI motherboard. PCI is the name of a
1856 bus system, i.e. the way the CPU talks to the other stuff inside
1857 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1858 VESA. If you have PCI, say Y, otherwise N.
1861 prompt "PCI access mode"
1862 depends on X86_32 && PCI
1865 On PCI systems, the BIOS can be used to detect the PCI devices and
1866 determine their configuration. However, some old PCI motherboards
1867 have BIOS bugs and may crash if this is done. Also, some embedded
1868 PCI-based systems don't have any BIOS at all. Linux can also try to
1869 detect the PCI hardware directly without using the BIOS.
1871 With this option, you can specify how Linux should detect the
1872 PCI devices. If you choose "BIOS", the BIOS will be used,
1873 if you choose "Direct", the BIOS won't be used, and if you
1874 choose "MMConfig", then PCI Express MMCONFIG will be used.
1875 If you choose "Any", the kernel will try MMCONFIG, then the
1876 direct access method and falls back to the BIOS if that doesn't
1877 work. If unsure, go with the default, which is "Any".
1882 config PCI_GOMMCONFIG
1899 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1901 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1904 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1908 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1912 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1919 bool "Support mmconfig PCI config space access"
1920 depends on X86_64 && PCI && ACPI
1922 config PCI_CNB20LE_QUIRK
1923 bool "Read CNB20LE Host Bridge Windows"
1926 Read the PCI windows out of the CNB20LE host bridge. This allows
1927 PCI hotplug to work on systems with the CNB20LE chipset which do
1931 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1932 depends on PCI_MSI && ACPI && EXPERIMENTAL
1934 DMA remapping (DMAR) devices support enables independent address
1935 translations for Direct Memory Access (DMA) from devices.
1936 These DMA remapping devices are reported via ACPI tables
1937 and include PCI device scope covered by these DMA
1940 config DMAR_DEFAULT_ON
1942 prompt "Enable DMA Remapping Devices by default"
1945 Selecting this option will enable a DMAR device at boot time if
1946 one is found. If this option is not selected, DMAR support can
1947 be enabled by passing intel_iommu=on to the kernel. It is
1948 recommended you say N here while the DMAR code remains
1951 config DMAR_BROKEN_GFX_WA
1952 bool "Workaround broken graphics drivers (going away soon)"
1953 depends on DMAR && BROKEN
1955 Current Graphics drivers tend to use physical address
1956 for DMA and avoid using DMA APIs. Setting this config
1957 option permits the IOMMU driver to set a unity map for
1958 all the OS-visible memory. Hence the driver can continue
1959 to use physical addresses for DMA, at least until this
1960 option is removed in the 2.6.32 kernel.
1962 config DMAR_FLOPPY_WA
1966 Floppy disk drivers are known to bypass DMA API calls
1967 thereby failing to work when IOMMU is enabled. This
1968 workaround will setup a 1:1 mapping for the first
1969 16MiB to make floppy (an ISA device) work.
1972 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1973 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1975 Supports Interrupt remapping for IO-APIC and MSI devices.
1976 To use x2apic mode in the CPU's which support x2APIC enhancements or
1977 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1979 source "drivers/pci/pcie/Kconfig"
1981 source "drivers/pci/Kconfig"
1983 # x86_64 have no ISA slots, but do have ISA-style DMA.
1992 Find out whether you have ISA slots on your motherboard. ISA is the
1993 name of a bus system, i.e. the way the CPU talks to the other stuff
1994 inside your box. Other bus systems are PCI, EISA, MicroChannel
1995 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1996 newer boards don't support it. If you have ISA, say Y, otherwise N.
2002 The Extended Industry Standard Architecture (EISA) bus was
2003 developed as an open alternative to the IBM MicroChannel bus.
2005 The EISA bus provided some of the features of the IBM MicroChannel
2006 bus while maintaining backward compatibility with cards made for
2007 the older ISA bus. The EISA bus saw limited use between 1988 and
2008 1995 when it was made obsolete by the PCI bus.
2010 Say Y here if you are building a kernel for an EISA-based machine.
2014 source "drivers/eisa/Kconfig"
2019 MicroChannel Architecture is found in some IBM PS/2 machines and
2020 laptops. It is a bus system similar to PCI or ISA. See
2021 <file:Documentation/mca.txt> (and especially the web page given
2022 there) before attempting to build an MCA bus kernel.
2024 source "drivers/mca/Kconfig"
2027 tristate "NatSemi SCx200 support"
2029 This provides basic support for National Semiconductor's
2030 (now AMD's) Geode processors. The driver probes for the
2031 PCI-IDs of several on-chip devices, so its a good dependency
2032 for other scx200_* drivers.
2034 If compiled as a module, the driver is named scx200.
2036 config SCx200HR_TIMER
2037 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2038 depends on SCx200 && GENERIC_TIME
2041 This driver provides a clocksource built upon the on-chip
2042 27MHz high-resolution timer. Its also a workaround for
2043 NSC Geode SC-1100's buggy TSC, which loses time when the
2044 processor goes idle (as is done by the scheduler). The
2045 other workaround is idle=poll boot option.
2048 bool "One Laptop Per Child support"
2051 Add support for detecting the unique features of the OLPC
2058 depends on CPU_SUP_AMD && PCI
2060 source "drivers/pcmcia/Kconfig"
2062 source "drivers/pci/hotplug/Kconfig"
2067 menu "Executable file formats / Emulations"
2069 source "fs/Kconfig.binfmt"
2071 config IA32_EMULATION
2072 bool "IA32 Emulation"
2074 select COMPAT_BINFMT_ELF
2076 Include code to run 32-bit programs under a 64-bit kernel. You should
2077 likely turn this on, unless you're 100% sure that you don't have any
2078 32-bit programs left.
2081 tristate "IA32 a.out support"
2082 depends on IA32_EMULATION
2084 Support old a.out binaries in the 32bit emulation.
2088 depends on IA32_EMULATION
2090 config COMPAT_FOR_U64_ALIGNMENT
2094 config SYSVIPC_COMPAT
2096 depends on COMPAT && SYSVIPC
2101 config HAVE_ATOMIC_IOMAP
2105 source "net/Kconfig"
2107 source "drivers/Kconfig"
2109 source "drivers/firmware/Kconfig"
2113 source "arch/x86/Kconfig.debug"
2115 source "security/Kconfig"
2117 source "crypto/Kconfig"
2119 source "arch/x86/kvm/Kconfig"
2121 source "lib/Kconfig"