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 GENERIC_ISA_DMA
121 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
123 config GENERIC_BUG_RELATIVE_POINTERS
126 config GENERIC_HWEIGHT
132 config ARCH_MAY_HAVE_PC_FDC
135 config RWSEM_GENERIC_SPINLOCK
138 config RWSEM_XCHGADD_ALGORITHM
141 config ARCH_HAS_CPU_IDLE_WAIT
144 config GENERIC_CALIBRATE_DELAY
147 config GENERIC_TIME_VSYSCALL
151 config ARCH_HAS_CPU_RELAX
154 config ARCH_HAS_DEFAULT_IDLE
157 config ARCH_HAS_CACHE_LINE_SIZE
160 config HAVE_SETUP_PER_CPU_AREA
163 config NEED_PER_CPU_EMBED_FIRST_CHUNK
166 config NEED_PER_CPU_PAGE_FIRST_CHUNK
169 config HAVE_CPUMASK_OF_CPU_MAP
172 config ARCH_HIBERNATION_POSSIBLE
175 config ARCH_SUSPEND_POSSIBLE
182 config ARCH_POPULATES_NODE_MAP
189 config ARCH_SUPPORTS_OPTIMIZED_INLINING
192 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
195 config HAVE_EARLY_RES
198 config HAVE_INTEL_TXT
200 depends on EXPERIMENTAL && DMAR && ACPI
202 # Use the generic interrupt handling code in kernel/irq/:
203 config GENERIC_HARDIRQS
206 config GENERIC_HARDIRQS_NO__DO_IRQ
209 config GENERIC_IRQ_PROBE
212 config GENERIC_PENDING_IRQ
214 depends on GENERIC_HARDIRQS && SMP
216 config USE_GENERIC_SMP_HELPERS
222 depends on X86_32 && SMP
226 depends on X86_64 && SMP
232 config X86_TRAMPOLINE
234 depends on SMP || (64BIT && ACPI_SLEEP)
236 config X86_32_LAZY_GS
238 depends on X86_32 && !CC_STACKPROTECTOR
242 source "init/Kconfig"
243 source "kernel/Kconfig.freezer"
245 menu "Processor type and features"
247 source "kernel/time/Kconfig"
250 bool "Symmetric multi-processing support"
252 This enables support for systems with more than one CPU. If you have
253 a system with only one CPU, like most personal computers, say N. If
254 you have a system with more than one CPU, say Y.
256 If you say N here, the kernel will run on single and multiprocessor
257 machines, but will use only one CPU of a multiprocessor machine. If
258 you say Y here, the kernel will run on many, but not all,
259 singleprocessor machines. On a singleprocessor machine, the kernel
260 will run faster if you say N here.
262 Note that if you say Y here and choose architecture "586" or
263 "Pentium" under "Processor family", the kernel will not work on 486
264 architectures. Similarly, multiprocessor kernels for the "PPro"
265 architecture may not work on all Pentium based boards.
267 People using multiprocessor machines who say Y here should also say
268 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
269 Management" code will be disabled if you say Y here.
271 See also <file:Documentation/i386/IO-APIC.txt>,
272 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
273 <http://www.tldp.org/docs.html#howto>.
275 If you don't know what to do here, say N.
278 bool "Support x2apic"
279 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
281 This enables x2apic support on CPUs that have this feature.
283 This allows 32-bit apic IDs (so it can support very large systems),
284 and accesses the local apic via MSRs not via mmio.
286 If you don't know what to do here, say N.
289 bool "Support sparse irq numbering"
290 depends on PCI_MSI || HT_IRQ
292 This enables support for sparse irqs. This is useful for distro
293 kernels that want to define a high CONFIG_NR_CPUS value but still
294 want to have low kernel memory footprint on smaller machines.
296 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
297 out the irq_desc[] array in a more NUMA-friendly way. )
299 If you don't know what to do here, say N.
303 depends on SPARSE_IRQ && NUMA
306 bool "Enable MPS table" if ACPI
308 depends on X86_LOCAL_APIC
310 For old smp systems that do not have proper acpi support. Newer systems
311 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
314 bool "Support for big SMP systems with more than 8 CPUs"
315 depends on X86_32 && SMP
317 This option is needed for the systems that have more than 8 CPUs
320 config X86_EXTENDED_PLATFORM
321 bool "Support for extended (non-PC) x86 platforms"
324 If you disable this option then the kernel will only support
325 standard PC platforms. (which covers the vast majority of
328 If you enable this option then you'll be able to select support
329 for the following (non-PC) 32 bit x86 platforms:
333 SGI 320/540 (Visual Workstation)
334 Summit/EXA (IBM x440)
335 Unisys ES7000 IA32 series
336 Moorestown MID devices
338 If you have one of these systems, or if you want to build a
339 generic distribution kernel, say Y here - otherwise say N.
343 config X86_EXTENDED_PLATFORM
344 bool "Support for extended (non-PC) x86 platforms"
347 If you disable this option then the kernel will only support
348 standard PC platforms. (which covers the vast majority of
351 If you enable this option then you'll be able to select support
352 for the following (non-PC) 64 bit x86 platforms:
356 If you have one of these systems, or if you want to build a
357 generic distribution kernel, say Y here - otherwise say N.
359 # This is an alphabetically sorted list of 64 bit extended platforms
360 # Please maintain the alphabetic order if and when there are additions
365 depends on X86_64 && PCI
366 depends on X86_EXTENDED_PLATFORM
368 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
369 supposed to run on these EM64T-based machines. Only choose this option
370 if you have one of these machines.
373 bool "SGI Ultraviolet"
375 depends on X86_EXTENDED_PLATFORM
377 depends on X86_X2APIC
379 This option is needed in order to support SGI Ultraviolet systems.
380 If you don't have one of these, you should say N here.
382 # Following is an alphabetically sorted list of 32 bit extended platforms
383 # Please maintain the alphabetic order if and when there are additions
388 depends on X86_EXTENDED_PLATFORM
390 Select this for an AMD Elan processor.
392 Do not use this option for K6/Athlon/Opteron processors!
394 If unsure, choose "PC-compatible" instead.
397 bool "Moorestown MID platform"
401 depends on X86_EXTENDED_PLATFORM
402 depends on X86_IO_APIC
405 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
406 Internet Device(MID) platform. Moorestown consists of two chips:
407 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
408 Unlike standard x86 PCs, Moorestown does not have many legacy devices
409 nor standard legacy replacement devices/features. e.g. Moorestown does
410 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
413 bool "RDC R-321x SoC"
415 depends on X86_EXTENDED_PLATFORM
417 select X86_REBOOTFIXUPS
419 This option is needed for RDC R-321x system-on-chip, also known
421 If you don't have one of these chips, you should say N here.
423 config X86_32_NON_STANDARD
424 bool "Support non-standard 32-bit SMP architectures"
425 depends on X86_32 && SMP
426 depends on X86_EXTENDED_PLATFORM
428 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
429 subarchitectures. It is intended for a generic binary kernel.
430 if you select them all, kernel will probe it one by one. and will
433 # Alphabetically sorted list of Non standard 32 bit platforms
436 bool "NUMAQ (IBM/Sequent)"
437 depends on X86_32_NON_STANDARD
442 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
443 NUMA multiquad box. This changes the way that processors are
444 bootstrapped, and uses Clustered Logical APIC addressing mode instead
445 of Flat Logical. You will need a new lynxer.elf file to flash your
446 firmware with - send email to <Martin.Bligh@us.ibm.com>.
448 config X86_SUPPORTS_MEMORY_FAILURE
450 # MCE code calls memory_failure():
452 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
453 depends on !X86_NUMAQ
454 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
455 depends on X86_64 || !SPARSEMEM
456 select ARCH_SUPPORTS_MEMORY_FAILURE
459 bool "SGI 320/540 (Visual Workstation)"
460 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
461 depends on X86_32_NON_STANDARD
463 The SGI Visual Workstation series is an IA32-based workstation
464 based on SGI systems chips with some legacy PC hardware attached.
466 Say Y here to create a kernel to run on the SGI 320 or 540.
468 A kernel compiled for the Visual Workstation will run on general
469 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
472 bool "Summit/EXA (IBM x440)"
473 depends on X86_32_NON_STANDARD
475 This option is needed for IBM systems that use the Summit/EXA chipset.
476 In particular, it is needed for the x440.
479 bool "Unisys ES7000 IA32 series"
480 depends on X86_32_NON_STANDARD && X86_BIGSMP
482 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
483 supposed to run on an IA32-based Unisys ES7000 system.
485 config SCHED_OMIT_FRAME_POINTER
487 prompt "Single-depth WCHAN output"
490 Calculate simpler /proc/<PID>/wchan values. If this option
491 is disabled then wchan values will recurse back to the
492 caller function. This provides more accurate wchan values,
493 at the expense of slightly more scheduling overhead.
495 If in doubt, say "Y".
497 menuconfig PARAVIRT_GUEST
498 bool "Paravirtualized guest support"
500 Say Y here to get to see options related to running Linux under
501 various hypervisors. This option alone does not add any kernel code.
503 If you say N, all options in this submenu will be skipped and disabled.
507 source "arch/x86/xen/Kconfig"
510 bool "VMI Guest support (DEPRECATED)"
514 VMI provides a paravirtualized interface to the VMware ESX server
515 (it could be used by other hypervisors in theory too, but is not
516 at the moment), by linking the kernel to a GPL-ed ROM module
517 provided by the hypervisor.
519 As of September 2009, VMware has started a phased retirement
520 of this feature from VMware's products. Please see
521 feature-removal-schedule.txt for details. If you are
522 planning to enable this option, please note that you cannot
523 live migrate a VMI enabled VM to a future VMware product,
524 which doesn't support VMI. So if you expect your kernel to
525 seamlessly migrate to newer VMware products, keep this
529 bool "KVM paravirtualized clock"
531 select PARAVIRT_CLOCK
533 Turning on this option will allow you to run a paravirtualized clock
534 when running over the KVM hypervisor. Instead of relying on a PIT
535 (or probably other) emulation by the underlying device model, the host
536 provides the guest with timing infrastructure such as time of day, and
540 bool "KVM Guest support"
543 This option enables various optimizations for running under the KVM
546 source "arch/x86/lguest/Kconfig"
549 bool "Enable paravirtualization code"
551 This changes the kernel so it can modify itself when it is run
552 under a hypervisor, potentially improving performance significantly
553 over full virtualization. However, when run without a hypervisor
554 the kernel is theoretically slower and slightly larger.
556 config PARAVIRT_SPINLOCKS
557 bool "Paravirtualization layer for spinlocks"
558 depends on PARAVIRT && SMP && EXPERIMENTAL
560 Paravirtualized spinlocks allow a pvops backend to replace the
561 spinlock implementation with something virtualization-friendly
562 (for example, block the virtual CPU rather than spinning).
564 Unfortunately the downside is an up to 5% performance hit on
565 native kernels, with various workloads.
567 If you are unsure how to answer this question, answer N.
569 config PARAVIRT_CLOCK
574 config PARAVIRT_DEBUG
575 bool "paravirt-ops debugging"
576 depends on PARAVIRT && DEBUG_KERNEL
578 Enable to debug paravirt_ops internals. Specifically, BUG if
579 a paravirt_op is missing when it is called.
583 bool "Disable Bootmem code"
585 Use early_res directly instead of bootmem before slab is ready.
586 - allocator (buddy) [generic]
587 - early allocator (bootmem) [generic]
588 - very early allocator (reserve_early*()) [x86]
589 - very very early allocator (early brk model) [x86]
590 So reduce one layer between early allocator to final allocator
596 This option adds a kernel parameter 'memtest', which allows memtest
598 memtest=0, mean disabled; -- default
599 memtest=1, mean do 1 test pattern;
601 memtest=4, mean do 4 test patterns.
602 If you are unsure how to answer this question, answer N.
604 config X86_SUMMIT_NUMA
606 depends on X86_32 && NUMA && X86_32_NON_STANDARD
608 config X86_CYCLONE_TIMER
610 depends on X86_32_NON_STANDARD
612 source "arch/x86/Kconfig.cpu"
616 prompt "HPET Timer Support" if X86_32
618 Use the IA-PC HPET (High Precision Event Timer) to manage
619 time in preference to the PIT and RTC, if a HPET is
621 HPET is the next generation timer replacing legacy 8254s.
622 The HPET provides a stable time base on SMP
623 systems, unlike the TSC, but it is more expensive to access,
624 as it is off-chip. You can find the HPET spec at
625 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
627 You can safely choose Y here. However, HPET will only be
628 activated if the platform and the BIOS support this feature.
629 Otherwise the 8254 will be used for timing services.
631 Choose N to continue using the legacy 8254 timer.
633 config HPET_EMULATE_RTC
635 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
639 prompt "Langwell APB Timer Support" if X86_MRST
641 APB timer is the replacement for 8254, HPET on X86 MID platforms.
642 The APBT provides a stable time base on SMP
643 systems, unlike the TSC, but it is more expensive to access,
644 as it is off-chip. APB timers are always running regardless of CPU
645 C states, they are used as per CPU clockevent device when possible.
647 # Mark as embedded because too many people got it wrong.
648 # The code disables itself when not needed.
651 bool "Enable DMI scanning" if EMBEDDED
653 Enabled scanning of DMI to identify machine quirks. Say Y
654 here unless you have verified that your setup is not
655 affected by entries in the DMI blacklist. Required by PNP
659 bool "GART IOMMU support" if EMBEDDED
662 depends on X86_64 && PCI && K8_NB
664 Support for full DMA access of devices with 32bit memory access only
665 on systems with more than 3GB. This is usually needed for USB,
666 sound, many IDE/SATA chipsets and some other devices.
667 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
668 based hardware IOMMU and a software bounce buffer based IOMMU used
669 on Intel systems and as fallback.
670 The code is only active when needed (enough memory and limited
671 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
675 bool "IBM Calgary IOMMU support"
677 depends on X86_64 && PCI && EXPERIMENTAL
679 Support for hardware IOMMUs in IBM's xSeries x366 and x460
680 systems. Needed to run systems with more than 3GB of memory
681 properly with 32-bit PCI devices that do not support DAC
682 (Double Address Cycle). Calgary also supports bus level
683 isolation, where all DMAs pass through the IOMMU. This
684 prevents them from going anywhere except their intended
685 destination. This catches hard-to-find kernel bugs and
686 mis-behaving drivers and devices that do not use the DMA-API
687 properly to set up their DMA buffers. The IOMMU can be
688 turned off at boot time with the iommu=off parameter.
689 Normally the kernel will make the right choice by itself.
692 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
694 prompt "Should Calgary be enabled by default?"
695 depends on CALGARY_IOMMU
697 Should Calgary be enabled by default? if you choose 'y', Calgary
698 will be used (if it exists). If you choose 'n', Calgary will not be
699 used even if it exists. If you choose 'n' and would like to use
700 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
704 bool "AMD IOMMU support"
707 depends on X86_64 && PCI && ACPI
709 With this option you can enable support for AMD IOMMU hardware in
710 your system. An IOMMU is a hardware component which provides
711 remapping of DMA memory accesses from devices. With an AMD IOMMU you
712 can isolate the the DMA memory of different devices and protect the
713 system from misbehaving device drivers or hardware.
715 You can find out if your system has an AMD IOMMU if you look into
716 your BIOS for an option to enable it or if you have an IVRS ACPI
719 config AMD_IOMMU_STATS
720 bool "Export AMD IOMMU statistics to debugfs"
724 This option enables code in the AMD IOMMU driver to collect various
725 statistics about whats happening in the driver and exports that
726 information to userspace via debugfs.
729 # need this always selected by IOMMU for the VIA workaround
733 Support for software bounce buffers used on x86-64 systems
734 which don't have a hardware IOMMU (e.g. the current generation
735 of Intel's x86-64 CPUs). Using this PCI devices which can only
736 access 32-bits of memory can be used on systems with more than
737 3 GB of memory. If unsure, say Y.
740 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
743 def_bool (AMD_IOMMU || DMAR)
746 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
747 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
748 select CPUMASK_OFFSTACK
750 Configure maximum number of CPUS and NUMA Nodes for this architecture.
754 int "Maximum number of CPUs" if SMP && !MAXSMP
755 range 2 8 if SMP && X86_32 && !X86_BIGSMP
756 range 2 512 if SMP && !MAXSMP
758 default "4096" if MAXSMP
759 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
762 This allows you to specify the maximum number of CPUs which this
763 kernel will support. The maximum supported value is 512 and the
764 minimum value which makes sense is 2.
766 This is purely to save memory - each supported CPU adds
767 approximately eight kilobytes to the kernel image.
770 bool "SMT (Hyperthreading) scheduler support"
773 SMT scheduler support improves the CPU scheduler's decision making
774 when dealing with Intel Pentium 4 chips with HyperThreading at a
775 cost of slightly increased overhead in some places. If unsure say
780 prompt "Multi-core scheduler support"
783 Multi-core scheduler support improves the CPU scheduler's decision
784 making when dealing with multi-core CPU chips at a cost of slightly
785 increased overhead in some places. If unsure say N here.
787 source "kernel/Kconfig.preempt"
790 bool "Local APIC support on uniprocessors"
791 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
793 A local APIC (Advanced Programmable Interrupt Controller) is an
794 integrated interrupt controller in the CPU. If you have a single-CPU
795 system which has a processor with a local APIC, you can say Y here to
796 enable and use it. If you say Y here even though your machine doesn't
797 have a local APIC, then the kernel will still run with no slowdown at
798 all. The local APIC supports CPU-generated self-interrupts (timer,
799 performance counters), and the NMI watchdog which detects hard
803 bool "IO-APIC support on uniprocessors"
804 depends on X86_UP_APIC
806 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
807 SMP-capable replacement for PC-style interrupt controllers. Most
808 SMP systems and many recent uniprocessor systems have one.
810 If you have a single-CPU system with an IO-APIC, you can say Y here
811 to use it. If you say Y here even though your machine doesn't have
812 an IO-APIC, then the kernel will still run with no slowdown at all.
814 config X86_LOCAL_APIC
816 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
820 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
822 config X86_VISWS_APIC
824 depends on X86_32 && X86_VISWS
826 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
827 bool "Reroute for broken boot IRQs"
828 depends on X86_IO_APIC
830 This option enables a workaround that fixes a source of
831 spurious interrupts. This is recommended when threaded
832 interrupt handling is used on systems where the generation of
833 superfluous "boot interrupts" cannot be disabled.
835 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
836 entry in the chipset's IO-APIC is masked (as, e.g. the RT
837 kernel does during interrupt handling). On chipsets where this
838 boot IRQ generation cannot be disabled, this workaround keeps
839 the original IRQ line masked so that only the equivalent "boot
840 IRQ" is delivered to the CPUs. The workaround also tells the
841 kernel to set up the IRQ handler on the boot IRQ line. In this
842 way only one interrupt is delivered to the kernel. Otherwise
843 the spurious second interrupt may cause the kernel to bring
844 down (vital) interrupt lines.
846 Only affects "broken" chipsets. Interrupt sharing may be
847 increased on these systems.
850 bool "Machine Check / overheating reporting"
852 Machine Check support allows the processor to notify the
853 kernel if it detects a problem (e.g. overheating, data corruption).
854 The action the kernel takes depends on the severity of the problem,
855 ranging from warning messages to halting the machine.
859 prompt "Intel MCE features"
860 depends on X86_MCE && X86_LOCAL_APIC
862 Additional support for intel specific MCE features such as
867 prompt "AMD MCE features"
868 depends on X86_MCE && X86_LOCAL_APIC
870 Additional support for AMD specific MCE features such as
871 the DRAM Error Threshold.
873 config X86_ANCIENT_MCE
874 bool "Support for old Pentium 5 / WinChip machine checks"
875 depends on X86_32 && X86_MCE
877 Include support for machine check handling on old Pentium 5 or WinChip
878 systems. These typically need to be enabled explicitely on the command
881 config X86_MCE_THRESHOLD
882 depends on X86_MCE_AMD || X86_MCE_INTEL
885 config X86_MCE_INJECT
887 tristate "Machine check injector support"
889 Provide support for injecting machine checks for testing purposes.
890 If you don't know what a machine check is and you don't do kernel
891 QA it is safe to say n.
893 config X86_THERMAL_VECTOR
895 depends on X86_MCE_INTEL
898 bool "Enable VM86 support" if EMBEDDED
902 This option is required by programs like DOSEMU to run 16-bit legacy
903 code on X86 processors. It also may be needed by software like
904 XFree86 to initialize some video cards via BIOS. Disabling this
905 option saves about 6k.
908 tristate "Toshiba Laptop support"
911 This adds a driver to safely access the System Management Mode of
912 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
913 not work on models with a Phoenix BIOS. The System Management Mode
914 is used to set the BIOS and power saving options on Toshiba portables.
916 For information on utilities to make use of this driver see the
917 Toshiba Linux utilities web site at:
918 <http://www.buzzard.org.uk/toshiba/>.
920 Say Y if you intend to run this kernel on a Toshiba portable.
924 tristate "Dell laptop support"
926 This adds a driver to safely access the System Management Mode
927 of the CPU on the Dell Inspiron 8000. The System Management Mode
928 is used to read cpu temperature and cooling fan status and to
929 control the fans on the I8K portables.
931 This driver has been tested only on the Inspiron 8000 but it may
932 also work with other Dell laptops. You can force loading on other
933 models by passing the parameter `force=1' to the module. Use at
936 For information on utilities to make use of this driver see the
937 I8K Linux utilities web site at:
938 <http://people.debian.org/~dz/i8k/>
940 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
943 config X86_REBOOTFIXUPS
944 bool "Enable X86 board specific fixups for reboot"
947 This enables chipset and/or board specific fixups to be done
948 in order to get reboot to work correctly. This is only needed on
949 some combinations of hardware and BIOS. The symptom, for which
950 this config is intended, is when reboot ends with a stalled/hung
953 Currently, the only fixup is for the Geode machines using
954 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
956 Say Y if you want to enable the fixup. Currently, it's safe to
957 enable this option even if you don't need it.
961 tristate "/dev/cpu/microcode - microcode support"
964 If you say Y here, you will be able to update the microcode on
965 certain Intel and AMD processors. The Intel support is for the
966 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
967 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
968 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
969 You will obviously need the actual microcode binary data itself
970 which is not shipped with the Linux kernel.
972 This option selects the general module only, you need to select
973 at least one vendor specific module as well.
975 To compile this driver as a module, choose M here: the
976 module will be called microcode.
978 config MICROCODE_INTEL
979 bool "Intel microcode patch loading support"
984 This options enables microcode patch loading support for Intel
987 For latest news and information on obtaining all the required
988 Intel ingredients for this driver, check:
989 <http://www.urbanmyth.org/microcode/>.
992 bool "AMD microcode patch loading support"
996 If you select this option, microcode patch loading support for AMD
997 processors will be enabled.
999 config MICROCODE_OLD_INTERFACE
1001 depends on MICROCODE
1004 tristate "/dev/cpu/*/msr - Model-specific register support"
1006 This device gives privileged processes access to the x86
1007 Model-Specific Registers (MSRs). It is a character device with
1008 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1009 MSR accesses are directed to a specific CPU on multi-processor
1013 tristate "/dev/cpu/*/cpuid - CPU information support"
1015 This device gives processes access to the x86 CPUID instruction to
1016 be executed on a specific processor. It is a character device
1017 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1021 prompt "High Memory Support"
1022 default HIGHMEM64G if X86_NUMAQ
1028 depends on !X86_NUMAQ
1030 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1031 However, the address space of 32-bit x86 processors is only 4
1032 Gigabytes large. That means that, if you have a large amount of
1033 physical memory, not all of it can be "permanently mapped" by the
1034 kernel. The physical memory that's not permanently mapped is called
1037 If you are compiling a kernel which will never run on a machine with
1038 more than 1 Gigabyte total physical RAM, answer "off" here (default
1039 choice and suitable for most users). This will result in a "3GB/1GB"
1040 split: 3GB are mapped so that each process sees a 3GB virtual memory
1041 space and the remaining part of the 4GB virtual memory space is used
1042 by the kernel to permanently map as much physical memory as
1045 If the machine has between 1 and 4 Gigabytes physical RAM, then
1048 If more than 4 Gigabytes is used then answer "64GB" here. This
1049 selection turns Intel PAE (Physical Address Extension) mode on.
1050 PAE implements 3-level paging on IA32 processors. PAE is fully
1051 supported by Linux, PAE mode is implemented on all recent Intel
1052 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1053 then the kernel will not boot on CPUs that don't support PAE!
1055 The actual amount of total physical memory will either be
1056 auto detected or can be forced by using a kernel command line option
1057 such as "mem=256M". (Try "man bootparam" or see the documentation of
1058 your boot loader (lilo or loadlin) about how to pass options to the
1059 kernel at boot time.)
1061 If unsure, say "off".
1065 depends on !X86_NUMAQ
1067 Select this if you have a 32-bit processor and between 1 and 4
1068 gigabytes of physical RAM.
1072 depends on !M386 && !M486
1075 Select this if you have a 32-bit processor and more than 4
1076 gigabytes of physical RAM.
1081 depends on EXPERIMENTAL
1082 prompt "Memory split" if EMBEDDED
1086 Select the desired split between kernel and user memory.
1088 If the address range available to the kernel is less than the
1089 physical memory installed, the remaining memory will be available
1090 as "high memory". Accessing high memory is a little more costly
1091 than low memory, as it needs to be mapped into the kernel first.
1092 Note that increasing the kernel address space limits the range
1093 available to user programs, making the address space there
1094 tighter. Selecting anything other than the default 3G/1G split
1095 will also likely make your kernel incompatible with binary-only
1098 If you are not absolutely sure what you are doing, leave this
1102 bool "3G/1G user/kernel split"
1103 config VMSPLIT_3G_OPT
1105 bool "3G/1G user/kernel split (for full 1G low memory)"
1107 bool "2G/2G user/kernel split"
1108 config VMSPLIT_2G_OPT
1110 bool "2G/2G user/kernel split (for full 2G low memory)"
1112 bool "1G/3G user/kernel split"
1117 default 0xB0000000 if VMSPLIT_3G_OPT
1118 default 0x80000000 if VMSPLIT_2G
1119 default 0x78000000 if VMSPLIT_2G_OPT
1120 default 0x40000000 if VMSPLIT_1G
1126 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1129 bool "PAE (Physical Address Extension) Support"
1130 depends on X86_32 && !HIGHMEM4G
1132 PAE is required for NX support, and furthermore enables
1133 larger swapspace support for non-overcommit purposes. It
1134 has the cost of more pagetable lookup overhead, and also
1135 consumes more pagetable space per process.
1137 config ARCH_PHYS_ADDR_T_64BIT
1138 def_bool X86_64 || X86_PAE
1140 config DIRECT_GBPAGES
1141 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1145 Allow the kernel linear mapping to use 1GB pages on CPUs that
1146 support it. This can improve the kernel's performance a tiny bit by
1147 reducing TLB pressure. If in doubt, say "Y".
1149 # Common NUMA Features
1151 bool "Numa Memory Allocation and Scheduler Support"
1153 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1154 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1156 Enable NUMA (Non Uniform Memory Access) support.
1158 The kernel will try to allocate memory used by a CPU on the
1159 local memory controller of the CPU and add some more
1160 NUMA awareness to the kernel.
1162 For 64-bit this is recommended if the system is Intel Core i7
1163 (or later), AMD Opteron, or EM64T NUMA.
1165 For 32-bit this is only needed on (rare) 32-bit-only platforms
1166 that support NUMA topologies, such as NUMAQ / Summit, or if you
1167 boot a 32-bit kernel on a 64-bit NUMA platform.
1169 Otherwise, you should say N.
1171 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1172 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1176 prompt "Old style AMD Opteron NUMA detection"
1177 depends on X86_64 && NUMA && PCI
1179 Enable K8 NUMA node topology detection. You should say Y here if
1180 you have a multi processor AMD K8 system. This uses an old
1181 method to read the NUMA configuration directly from the builtin
1182 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1183 instead, which also takes priority if both are compiled in.
1185 config X86_64_ACPI_NUMA
1187 prompt "ACPI NUMA detection"
1188 depends on X86_64 && NUMA && ACPI && PCI
1191 Enable ACPI SRAT based node topology detection.
1193 # Some NUMA nodes have memory ranges that span
1194 # other nodes. Even though a pfn is valid and
1195 # between a node's start and end pfns, it may not
1196 # reside on that node. See memmap_init_zone()
1198 config NODES_SPAN_OTHER_NODES
1200 depends on X86_64_ACPI_NUMA
1203 bool "NUMA emulation"
1204 depends on X86_64 && NUMA
1206 Enable NUMA emulation. A flat machine will be split
1207 into virtual nodes when booted with "numa=fake=N", where N is the
1208 number of nodes. This is only useful for debugging.
1211 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1213 default "10" if MAXSMP
1214 default "6" if X86_64
1215 default "4" if X86_NUMAQ
1217 depends on NEED_MULTIPLE_NODES
1219 Specify the maximum number of NUMA Nodes available on the target
1220 system. Increases memory reserved to accommodate various tables.
1222 config HAVE_ARCH_BOOTMEM
1224 depends on X86_32 && NUMA
1226 config ARCH_HAVE_MEMORY_PRESENT
1228 depends on X86_32 && DISCONTIGMEM
1230 config NEED_NODE_MEMMAP_SIZE
1232 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1234 config HAVE_ARCH_ALLOC_REMAP
1236 depends on X86_32 && NUMA
1238 config ARCH_FLATMEM_ENABLE
1240 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1242 config ARCH_DISCONTIGMEM_ENABLE
1244 depends on NUMA && X86_32
1246 config ARCH_DISCONTIGMEM_DEFAULT
1248 depends on NUMA && X86_32
1250 config ARCH_PROC_KCORE_TEXT
1252 depends on X86_64 && PROC_KCORE
1254 config ARCH_SPARSEMEM_DEFAULT
1258 config ARCH_SPARSEMEM_ENABLE
1260 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1261 select SPARSEMEM_STATIC if X86_32
1262 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1264 config ARCH_SELECT_MEMORY_MODEL
1266 depends on ARCH_SPARSEMEM_ENABLE
1268 config ARCH_MEMORY_PROBE
1270 depends on MEMORY_HOTPLUG
1272 config ILLEGAL_POINTER_VALUE
1275 default 0xdead000000000000 if X86_64
1280 bool "Allocate 3rd-level pagetables from highmem"
1283 The VM uses one page table entry for each page of physical memory.
1284 For systems with a lot of RAM, this can be wasteful of precious
1285 low memory. Setting this option will put user-space page table
1286 entries in high memory.
1288 config X86_CHECK_BIOS_CORRUPTION
1289 bool "Check for low memory corruption"
1291 Periodically check for memory corruption in low memory, which
1292 is suspected to be caused by BIOS. Even when enabled in the
1293 configuration, it is disabled at runtime. Enable it by
1294 setting "memory_corruption_check=1" on the kernel command
1295 line. By default it scans the low 64k of memory every 60
1296 seconds; see the memory_corruption_check_size and
1297 memory_corruption_check_period parameters in
1298 Documentation/kernel-parameters.txt to adjust this.
1300 When enabled with the default parameters, this option has
1301 almost no overhead, as it reserves a relatively small amount
1302 of memory and scans it infrequently. It both detects corruption
1303 and prevents it from affecting the running system.
1305 It is, however, intended as a diagnostic tool; if repeatable
1306 BIOS-originated corruption always affects the same memory,
1307 you can use memmap= to prevent the kernel from using that
1310 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1311 bool "Set the default setting of memory_corruption_check"
1312 depends on X86_CHECK_BIOS_CORRUPTION
1315 Set whether the default state of memory_corruption_check is
1318 config X86_RESERVE_LOW_64K
1319 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1322 Reserve the first 64K of physical RAM on BIOSes that are known
1323 to potentially corrupt that memory range. A numbers of BIOSes are
1324 known to utilize this area during suspend/resume, so it must not
1325 be used by the kernel.
1327 Set this to N if you are absolutely sure that you trust the BIOS
1328 to get all its memory reservations and usages right.
1330 If you have doubts about the BIOS (e.g. suspend/resume does not
1331 work or there's kernel crashes after certain hardware hotplug
1332 events) and it's not AMI or Phoenix, then you might want to enable
1333 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1334 corruption patterns.
1338 config MATH_EMULATION
1340 prompt "Math emulation" if X86_32
1342 Linux can emulate a math coprocessor (used for floating point
1343 operations) if you don't have one. 486DX and Pentium processors have
1344 a math coprocessor built in, 486SX and 386 do not, unless you added
1345 a 487DX or 387, respectively. (The messages during boot time can
1346 give you some hints here ["man dmesg"].) Everyone needs either a
1347 coprocessor or this emulation.
1349 If you don't have a math coprocessor, you need to say Y here; if you
1350 say Y here even though you have a coprocessor, the coprocessor will
1351 be used nevertheless. (This behavior can be changed with the kernel
1352 command line option "no387", which comes handy if your coprocessor
1353 is broken. Try "man bootparam" or see the documentation of your boot
1354 loader (lilo or loadlin) about how to pass options to the kernel at
1355 boot time.) This means that it is a good idea to say Y here if you
1356 intend to use this kernel on different machines.
1358 More information about the internals of the Linux math coprocessor
1359 emulation can be found in <file:arch/x86/math-emu/README>.
1361 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1362 kernel, it won't hurt.
1366 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1368 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1369 the Memory Type Range Registers (MTRRs) may be used to control
1370 processor access to memory ranges. This is most useful if you have
1371 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1372 allows bus write transfers to be combined into a larger transfer
1373 before bursting over the PCI/AGP bus. This can increase performance
1374 of image write operations 2.5 times or more. Saying Y here creates a
1375 /proc/mtrr file which may be used to manipulate your processor's
1376 MTRRs. Typically the X server should use this.
1378 This code has a reasonably generic interface so that similar
1379 control registers on other processors can be easily supported
1382 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1383 Registers (ARRs) which provide a similar functionality to MTRRs. For
1384 these, the ARRs are used to emulate the MTRRs.
1385 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1386 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1387 write-combining. All of these processors are supported by this code
1388 and it makes sense to say Y here if you have one of them.
1390 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1391 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1392 can lead to all sorts of problems, so it's good to say Y here.
1394 You can safely say Y even if your machine doesn't have MTRRs, you'll
1395 just add about 9 KB to your kernel.
1397 See <file:Documentation/x86/mtrr.txt> for more information.
1399 config MTRR_SANITIZER
1401 prompt "MTRR cleanup support"
1404 Convert MTRR layout from continuous to discrete, so X drivers can
1405 add writeback entries.
1407 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1408 The largest mtrr entry size for a continuous block can be set with
1413 config MTRR_SANITIZER_ENABLE_DEFAULT
1414 int "MTRR cleanup enable value (0-1)"
1417 depends on MTRR_SANITIZER
1419 Enable mtrr cleanup default value
1421 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1422 int "MTRR cleanup spare reg num (0-7)"
1425 depends on MTRR_SANITIZER
1427 mtrr cleanup spare entries default, it can be changed via
1428 mtrr_spare_reg_nr=N on the kernel command line.
1432 prompt "x86 PAT support" if EMBEDDED
1435 Use PAT attributes to setup page level cache control.
1437 PATs are the modern equivalents of MTRRs and are much more
1438 flexible than MTRRs.
1440 Say N here if you see bootup problems (boot crash, boot hang,
1441 spontaneous reboots) or a non-working video driver.
1445 config ARCH_USES_PG_UNCACHED
1450 bool "EFI runtime service support"
1453 This enables the kernel to use EFI runtime services that are
1454 available (such as the EFI variable services).
1456 This option is only useful on systems that have EFI firmware.
1457 In addition, you should use the latest ELILO loader available
1458 at <http://elilo.sourceforge.net> in order to take advantage
1459 of EFI runtime services. However, even with this option, the
1460 resultant kernel should continue to boot on existing non-EFI
1465 prompt "Enable seccomp to safely compute untrusted bytecode"
1467 This kernel feature is useful for number crunching applications
1468 that may need to compute untrusted bytecode during their
1469 execution. By using pipes or other transports made available to
1470 the process as file descriptors supporting the read/write
1471 syscalls, it's possible to isolate those applications in
1472 their own address space using seccomp. Once seccomp is
1473 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1474 and the task is only allowed to execute a few safe syscalls
1475 defined by each seccomp mode.
1477 If unsure, say Y. Only embedded should say N here.
1479 config CC_STACKPROTECTOR
1480 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1482 This option turns on the -fstack-protector GCC feature. This
1483 feature puts, at the beginning of functions, a canary value on
1484 the stack just before the return address, and validates
1485 the value just before actually returning. Stack based buffer
1486 overflows (that need to overwrite this return address) now also
1487 overwrite the canary, which gets detected and the attack is then
1488 neutralized via a kernel panic.
1490 This feature requires gcc version 4.2 or above, or a distribution
1491 gcc with the feature backported. Older versions are automatically
1492 detected and for those versions, this configuration option is
1493 ignored. (and a warning is printed during bootup)
1495 source kernel/Kconfig.hz
1498 bool "kexec system call"
1500 kexec is a system call that implements the ability to shutdown your
1501 current kernel, and to start another kernel. It is like a reboot
1502 but it is independent of the system firmware. And like a reboot
1503 you can start any kernel with it, not just Linux.
1505 The name comes from the similarity to the exec system call.
1507 It is an ongoing process to be certain the hardware in a machine
1508 is properly shutdown, so do not be surprised if this code does not
1509 initially work for you. It may help to enable device hotplugging
1510 support. As of this writing the exact hardware interface is
1511 strongly in flux, so no good recommendation can be made.
1514 bool "kernel crash dumps"
1515 depends on X86_64 || (X86_32 && HIGHMEM)
1517 Generate crash dump after being started by kexec.
1518 This should be normally only set in special crash dump kernels
1519 which are loaded in the main kernel with kexec-tools into
1520 a specially reserved region and then later executed after
1521 a crash by kdump/kexec. The crash dump kernel must be compiled
1522 to a memory address not used by the main kernel or BIOS using
1523 PHYSICAL_START, or it must be built as a relocatable image
1524 (CONFIG_RELOCATABLE=y).
1525 For more details see Documentation/kdump/kdump.txt
1528 bool "kexec jump (EXPERIMENTAL)"
1529 depends on EXPERIMENTAL
1530 depends on KEXEC && HIBERNATION
1532 Jump between original kernel and kexeced kernel and invoke
1533 code in physical address mode via KEXEC
1535 config PHYSICAL_START
1536 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1539 This gives the physical address where the kernel is loaded.
1541 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1542 bzImage will decompress itself to above physical address and
1543 run from there. Otherwise, bzImage will run from the address where
1544 it has been loaded by the boot loader and will ignore above physical
1547 In normal kdump cases one does not have to set/change this option
1548 as now bzImage can be compiled as a completely relocatable image
1549 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1550 address. This option is mainly useful for the folks who don't want
1551 to use a bzImage for capturing the crash dump and want to use a
1552 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1553 to be specifically compiled to run from a specific memory area
1554 (normally a reserved region) and this option comes handy.
1556 So if you are using bzImage for capturing the crash dump,
1557 leave the value here unchanged to 0x1000000 and set
1558 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1559 for capturing the crash dump change this value to start of
1560 the reserved region. In other words, it can be set based on
1561 the "X" value as specified in the "crashkernel=YM@XM"
1562 command line boot parameter passed to the panic-ed
1563 kernel. Please take a look at Documentation/kdump/kdump.txt
1564 for more details about crash dumps.
1566 Usage of bzImage for capturing the crash dump is recommended as
1567 one does not have to build two kernels. Same kernel can be used
1568 as production kernel and capture kernel. Above option should have
1569 gone away after relocatable bzImage support is introduced. But it
1570 is present because there are users out there who continue to use
1571 vmlinux for dump capture. This option should go away down the
1574 Don't change this unless you know what you are doing.
1577 bool "Build a relocatable kernel"
1580 This builds a kernel image that retains relocation information
1581 so it can be loaded someplace besides the default 1MB.
1582 The relocations tend to make the kernel binary about 10% larger,
1583 but are discarded at runtime.
1585 One use is for the kexec on panic case where the recovery kernel
1586 must live at a different physical address than the primary
1589 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1590 it has been loaded at and the compile time physical address
1591 (CONFIG_PHYSICAL_START) is ignored.
1593 # Relocation on x86-32 needs some additional build support
1594 config X86_NEED_RELOCS
1596 depends on X86_32 && RELOCATABLE
1598 config PHYSICAL_ALIGN
1599 hex "Alignment value to which kernel should be aligned" if X86_32
1601 range 0x2000 0x1000000
1603 This value puts the alignment restrictions on physical address
1604 where kernel is loaded and run from. Kernel is compiled for an
1605 address which meets above alignment restriction.
1607 If bootloader loads the kernel at a non-aligned address and
1608 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1609 address aligned to above value and run from there.
1611 If bootloader loads the kernel at a non-aligned address and
1612 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1613 load address and decompress itself to the address it has been
1614 compiled for and run from there. The address for which kernel is
1615 compiled already meets above alignment restrictions. Hence the
1616 end result is that kernel runs from a physical address meeting
1617 above alignment restrictions.
1619 Don't change this unless you know what you are doing.
1622 bool "Support for hot-pluggable CPUs"
1623 depends on SMP && HOTPLUG
1625 Say Y here to allow turning CPUs off and on. CPUs can be
1626 controlled through /sys/devices/system/cpu.
1627 ( Note: power management support will enable this option
1628 automatically on SMP systems. )
1629 Say N if you want to disable CPU hotplug.
1633 prompt "Compat VDSO support"
1634 depends on X86_32 || IA32_EMULATION
1636 Map the 32-bit VDSO to the predictable old-style address too.
1638 Say N here if you are running a sufficiently recent glibc
1639 version (2.3.3 or later), to remove the high-mapped
1640 VDSO mapping and to exclusively use the randomized VDSO.
1645 bool "Built-in kernel command line"
1647 Allow for specifying boot arguments to the kernel at
1648 build time. On some systems (e.g. embedded ones), it is
1649 necessary or convenient to provide some or all of the
1650 kernel boot arguments with the kernel itself (that is,
1651 to not rely on the boot loader to provide them.)
1653 To compile command line arguments into the kernel,
1654 set this option to 'Y', then fill in the
1655 the boot arguments in CONFIG_CMDLINE.
1657 Systems with fully functional boot loaders (i.e. non-embedded)
1658 should leave this option set to 'N'.
1661 string "Built-in kernel command string"
1662 depends on CMDLINE_BOOL
1665 Enter arguments here that should be compiled into the kernel
1666 image and used at boot time. If the boot loader provides a
1667 command line at boot time, it is appended to this string to
1668 form the full kernel command line, when the system boots.
1670 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1671 change this behavior.
1673 In most cases, the command line (whether built-in or provided
1674 by the boot loader) should specify the device for the root
1677 config CMDLINE_OVERRIDE
1678 bool "Built-in command line overrides boot loader arguments"
1679 depends on CMDLINE_BOOL
1681 Set this option to 'Y' to have the kernel ignore the boot loader
1682 command line, and use ONLY the built-in command line.
1684 This is used to work around broken boot loaders. This should
1685 be set to 'N' under normal conditions.
1689 config ARCH_ENABLE_MEMORY_HOTPLUG
1691 depends on X86_64 || (X86_32 && HIGHMEM)
1693 config ARCH_ENABLE_MEMORY_HOTREMOVE
1695 depends on MEMORY_HOTPLUG
1697 config HAVE_ARCH_EARLY_PFN_TO_NID
1701 menu "Power management and ACPI options"
1703 config ARCH_HIBERNATION_HEADER
1705 depends on X86_64 && HIBERNATION
1707 source "kernel/power/Kconfig"
1709 source "drivers/acpi/Kconfig"
1711 source "drivers/sfi/Kconfig"
1715 depends on APM || APM_MODULE
1718 tristate "APM (Advanced Power Management) BIOS support"
1719 depends on X86_32 && PM_SLEEP
1721 APM is a BIOS specification for saving power using several different
1722 techniques. This is mostly useful for battery powered laptops with
1723 APM compliant BIOSes. If you say Y here, the system time will be
1724 reset after a RESUME operation, the /proc/apm device will provide
1725 battery status information, and user-space programs will receive
1726 notification of APM "events" (e.g. battery status change).
1728 If you select "Y" here, you can disable actual use of the APM
1729 BIOS by passing the "apm=off" option to the kernel at boot time.
1731 Note that the APM support is almost completely disabled for
1732 machines with more than one CPU.
1734 In order to use APM, you will need supporting software. For location
1735 and more information, read <file:Documentation/power/pm.txt> and the
1736 Battery Powered Linux mini-HOWTO, available from
1737 <http://www.tldp.org/docs.html#howto>.
1739 This driver does not spin down disk drives (see the hdparm(8)
1740 manpage ("man 8 hdparm") for that), and it doesn't turn off
1741 VESA-compliant "green" monitors.
1743 This driver does not support the TI 4000M TravelMate and the ACER
1744 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1745 desktop machines also don't have compliant BIOSes, and this driver
1746 may cause those machines to panic during the boot phase.
1748 Generally, if you don't have a battery in your machine, there isn't
1749 much point in using this driver and you should say N. If you get
1750 random kernel OOPSes or reboots that don't seem to be related to
1751 anything, try disabling/enabling this option (or disabling/enabling
1754 Some other things you should try when experiencing seemingly random,
1757 1) make sure that you have enough swap space and that it is
1759 2) pass the "no-hlt" option to the kernel
1760 3) switch on floating point emulation in the kernel and pass
1761 the "no387" option to the kernel
1762 4) pass the "floppy=nodma" option to the kernel
1763 5) pass the "mem=4M" option to the kernel (thereby disabling
1764 all but the first 4 MB of RAM)
1765 6) make sure that the CPU is not over clocked.
1766 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1767 8) disable the cache from your BIOS settings
1768 9) install a fan for the video card or exchange video RAM
1769 10) install a better fan for the CPU
1770 11) exchange RAM chips
1771 12) exchange the motherboard.
1773 To compile this driver as a module, choose M here: the
1774 module will be called apm.
1778 config APM_IGNORE_USER_SUSPEND
1779 bool "Ignore USER SUSPEND"
1781 This option will ignore USER SUSPEND requests. On machines with a
1782 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1783 series notebooks, it is necessary to say Y because of a BIOS bug.
1785 config APM_DO_ENABLE
1786 bool "Enable PM at boot time"
1788 Enable APM features at boot time. From page 36 of the APM BIOS
1789 specification: "When disabled, the APM BIOS does not automatically
1790 power manage devices, enter the Standby State, enter the Suspend
1791 State, or take power saving steps in response to CPU Idle calls."
1792 This driver will make CPU Idle calls when Linux is idle (unless this
1793 feature is turned off -- see "Do CPU IDLE calls", below). This
1794 should always save battery power, but more complicated APM features
1795 will be dependent on your BIOS implementation. You may need to turn
1796 this option off if your computer hangs at boot time when using APM
1797 support, or if it beeps continuously instead of suspending. Turn
1798 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1799 T400CDT. This is off by default since most machines do fine without
1803 bool "Make CPU Idle calls when idle"
1805 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1806 On some machines, this can activate improved power savings, such as
1807 a slowed CPU clock rate, when the machine is idle. These idle calls
1808 are made after the idle loop has run for some length of time (e.g.,
1809 333 mS). On some machines, this will cause a hang at boot time or
1810 whenever the CPU becomes idle. (On machines with more than one CPU,
1811 this option does nothing.)
1813 config APM_DISPLAY_BLANK
1814 bool "Enable console blanking using APM"
1816 Enable console blanking using the APM. Some laptops can use this to
1817 turn off the LCD backlight when the screen blanker of the Linux
1818 virtual console blanks the screen. Note that this is only used by
1819 the virtual console screen blanker, and won't turn off the backlight
1820 when using the X Window system. This also doesn't have anything to
1821 do with your VESA-compliant power-saving monitor. Further, this
1822 option doesn't work for all laptops -- it might not turn off your
1823 backlight at all, or it might print a lot of errors to the console,
1824 especially if you are using gpm.
1826 config APM_ALLOW_INTS
1827 bool "Allow interrupts during APM BIOS calls"
1829 Normally we disable external interrupts while we are making calls to
1830 the APM BIOS as a measure to lessen the effects of a badly behaving
1831 BIOS implementation. The BIOS should reenable interrupts if it
1832 needs to. Unfortunately, some BIOSes do not -- especially those in
1833 many of the newer IBM Thinkpads. If you experience hangs when you
1834 suspend, try setting this to Y. Otherwise, say N.
1838 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1840 source "drivers/cpuidle/Kconfig"
1842 source "drivers/idle/Kconfig"
1847 menu "Bus options (PCI etc.)"
1852 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1854 Find out whether you have a PCI motherboard. PCI is the name of a
1855 bus system, i.e. the way the CPU talks to the other stuff inside
1856 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1857 VESA. If you have PCI, say Y, otherwise N.
1860 prompt "PCI access mode"
1861 depends on X86_32 && PCI
1864 On PCI systems, the BIOS can be used to detect the PCI devices and
1865 determine their configuration. However, some old PCI motherboards
1866 have BIOS bugs and may crash if this is done. Also, some embedded
1867 PCI-based systems don't have any BIOS at all. Linux can also try to
1868 detect the PCI hardware directly without using the BIOS.
1870 With this option, you can specify how Linux should detect the
1871 PCI devices. If you choose "BIOS", the BIOS will be used,
1872 if you choose "Direct", the BIOS won't be used, and if you
1873 choose "MMConfig", then PCI Express MMCONFIG will be used.
1874 If you choose "Any", the kernel will try MMCONFIG, then the
1875 direct access method and falls back to the BIOS if that doesn't
1876 work. If unsure, go with the default, which is "Any".
1881 config PCI_GOMMCONFIG
1898 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1900 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1903 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1907 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1911 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1918 bool "Support mmconfig PCI config space access"
1919 depends on X86_64 && PCI && ACPI
1922 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1923 depends on PCI_MSI && ACPI && EXPERIMENTAL
1925 DMA remapping (DMAR) devices support enables independent address
1926 translations for Direct Memory Access (DMA) from devices.
1927 These DMA remapping devices are reported via ACPI tables
1928 and include PCI device scope covered by these DMA
1931 config DMAR_DEFAULT_ON
1933 prompt "Enable DMA Remapping Devices by default"
1936 Selecting this option will enable a DMAR device at boot time if
1937 one is found. If this option is not selected, DMAR support can
1938 be enabled by passing intel_iommu=on to the kernel. It is
1939 recommended you say N here while the DMAR code remains
1942 config DMAR_BROKEN_GFX_WA
1943 bool "Workaround broken graphics drivers (going away soon)"
1944 depends on DMAR && BROKEN
1946 Current Graphics drivers tend to use physical address
1947 for DMA and avoid using DMA APIs. Setting this config
1948 option permits the IOMMU driver to set a unity map for
1949 all the OS-visible memory. Hence the driver can continue
1950 to use physical addresses for DMA, at least until this
1951 option is removed in the 2.6.32 kernel.
1953 config DMAR_FLOPPY_WA
1957 Floppy disk drivers are known to bypass DMA API calls
1958 thereby failing to work when IOMMU is enabled. This
1959 workaround will setup a 1:1 mapping for the first
1960 16MiB to make floppy (an ISA device) work.
1963 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1964 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1966 Supports Interrupt remapping for IO-APIC and MSI devices.
1967 To use x2apic mode in the CPU's which support x2APIC enhancements or
1968 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1970 source "drivers/pci/pcie/Kconfig"
1972 source "drivers/pci/Kconfig"
1974 # x86_64 have no ISA slots, but do have ISA-style DMA.
1983 Find out whether you have ISA slots on your motherboard. ISA is the
1984 name of a bus system, i.e. the way the CPU talks to the other stuff
1985 inside your box. Other bus systems are PCI, EISA, MicroChannel
1986 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1987 newer boards don't support it. If you have ISA, say Y, otherwise N.
1993 The Extended Industry Standard Architecture (EISA) bus was
1994 developed as an open alternative to the IBM MicroChannel bus.
1996 The EISA bus provided some of the features of the IBM MicroChannel
1997 bus while maintaining backward compatibility with cards made for
1998 the older ISA bus. The EISA bus saw limited use between 1988 and
1999 1995 when it was made obsolete by the PCI bus.
2001 Say Y here if you are building a kernel for an EISA-based machine.
2005 source "drivers/eisa/Kconfig"
2010 MicroChannel Architecture is found in some IBM PS/2 machines and
2011 laptops. It is a bus system similar to PCI or ISA. See
2012 <file:Documentation/mca.txt> (and especially the web page given
2013 there) before attempting to build an MCA bus kernel.
2015 source "drivers/mca/Kconfig"
2018 tristate "NatSemi SCx200 support"
2020 This provides basic support for National Semiconductor's
2021 (now AMD's) Geode processors. The driver probes for the
2022 PCI-IDs of several on-chip devices, so its a good dependency
2023 for other scx200_* drivers.
2025 If compiled as a module, the driver is named scx200.
2027 config SCx200HR_TIMER
2028 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2029 depends on SCx200 && GENERIC_TIME
2032 This driver provides a clocksource built upon the on-chip
2033 27MHz high-resolution timer. Its also a workaround for
2034 NSC Geode SC-1100's buggy TSC, which loses time when the
2035 processor goes idle (as is done by the scheduler). The
2036 other workaround is idle=poll boot option.
2039 bool "One Laptop Per Child support"
2042 Add support for detecting the unique features of the OLPC
2049 depends on CPU_SUP_AMD && PCI
2051 source "drivers/pcmcia/Kconfig"
2053 source "drivers/pci/hotplug/Kconfig"
2058 menu "Executable file formats / Emulations"
2060 source "fs/Kconfig.binfmt"
2062 config IA32_EMULATION
2063 bool "IA32 Emulation"
2065 select COMPAT_BINFMT_ELF
2067 Include code to run 32-bit programs under a 64-bit kernel. You should
2068 likely turn this on, unless you're 100% sure that you don't have any
2069 32-bit programs left.
2072 tristate "IA32 a.out support"
2073 depends on IA32_EMULATION
2075 Support old a.out binaries in the 32bit emulation.
2079 depends on IA32_EMULATION
2081 config COMPAT_FOR_U64_ALIGNMENT
2085 config SYSVIPC_COMPAT
2087 depends on COMPAT && SYSVIPC
2092 config HAVE_ATOMIC_IOMAP
2096 source "net/Kconfig"
2098 source "drivers/Kconfig"
2100 source "drivers/firmware/Kconfig"
2104 source "arch/x86/Kconfig.debug"
2106 source "security/Kconfig"
2108 source "crypto/Kconfig"
2110 source "arch/x86/kvm/Kconfig"
2112 source "lib/Kconfig"