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_COUNTERS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_FTRACE_SYSCALLS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_DMA_API_DEBUG
49 select HAVE_KERNEL_GZIP
50 select HAVE_KERNEL_BZIP2
51 select HAVE_KERNEL_LZMA
52 select HAVE_ARCH_KMEMCHECK
56 default "elf32-i386" if X86_32
57 default "elf64-x86-64" if X86_64
61 default "arch/x86/configs/i386_defconfig" if X86_32
62 default "arch/x86/configs/x86_64_defconfig" if X86_64
67 config GENERIC_CMOS_UPDATE
70 config CLOCKSOURCE_WATCHDOG
73 config GENERIC_CLOCKEVENTS
76 config GENERIC_CLOCKEVENTS_BROADCAST
78 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
80 config LOCKDEP_SUPPORT
83 config STACKTRACE_SUPPORT
86 config HAVE_LATENCYTOP_SUPPORT
89 config FAST_CMPXCHG_LOCAL
102 config GENERIC_ISA_DMA
111 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
113 config GENERIC_BUG_RELATIVE_POINTERS
116 config GENERIC_HWEIGHT
122 config ARCH_MAY_HAVE_PC_FDC
125 config RWSEM_GENERIC_SPINLOCK
128 config RWSEM_XCHGADD_ALGORITHM
131 config ARCH_HAS_CPU_IDLE_WAIT
134 config GENERIC_CALIBRATE_DELAY
137 config GENERIC_TIME_VSYSCALL
141 config ARCH_HAS_CPU_RELAX
144 config ARCH_HAS_DEFAULT_IDLE
147 config ARCH_HAS_CACHE_LINE_SIZE
150 config HAVE_SETUP_PER_CPU_AREA
153 config NEED_PER_CPU_EMBED_FIRST_CHUNK
156 config NEED_PER_CPU_PAGE_FIRST_CHUNK
159 config NEED_PER_CPU_LPAGE_FIRST_CHUNK
161 depends on NEED_MULTIPLE_NODES
163 config HAVE_CPUMASK_OF_CPU_MAP
166 config ARCH_HIBERNATION_POSSIBLE
169 config ARCH_SUSPEND_POSSIBLE
176 config ARCH_POPULATES_NODE_MAP
183 config ARCH_SUPPORTS_OPTIMIZED_INLINING
186 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
189 # Use the generic interrupt handling code in kernel/irq/:
190 config GENERIC_HARDIRQS
194 config GENERIC_HARDIRQS_NO__DO_IRQ
197 config GENERIC_IRQ_PROBE
201 config GENERIC_PENDING_IRQ
203 depends on GENERIC_HARDIRQS && SMP
206 config USE_GENERIC_SMP_HELPERS
212 depends on X86_32 && SMP
216 depends on X86_64 && SMP
223 config X86_TRAMPOLINE
225 depends on SMP || (64BIT && ACPI_SLEEP)
228 config X86_32_LAZY_GS
230 depends on X86_32 && !CC_STACKPROTECTOR
234 source "init/Kconfig"
235 source "kernel/Kconfig.freezer"
237 menu "Processor type and features"
239 source "kernel/time/Kconfig"
242 bool "Symmetric multi-processing support"
244 This enables support for systems with more than one CPU. If you have
245 a system with only one CPU, like most personal computers, say N. If
246 you have a system with more than one CPU, say Y.
248 If you say N here, the kernel will run on single and multiprocessor
249 machines, but will use only one CPU of a multiprocessor machine. If
250 you say Y here, the kernel will run on many, but not all,
251 singleprocessor machines. On a singleprocessor machine, the kernel
252 will run faster if you say N here.
254 Note that if you say Y here and choose architecture "586" or
255 "Pentium" under "Processor family", the kernel will not work on 486
256 architectures. Similarly, multiprocessor kernels for the "PPro"
257 architecture may not work on all Pentium based boards.
259 People using multiprocessor machines who say Y here should also say
260 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
261 Management" code will be disabled if you say Y here.
263 See also <file:Documentation/i386/IO-APIC.txt>,
264 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
265 <http://www.tldp.org/docs.html#howto>.
267 If you don't know what to do here, say N.
270 bool "Support x2apic"
271 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
273 This enables x2apic support on CPUs that have this feature.
275 This allows 32-bit apic IDs (so it can support very large systems),
276 and accesses the local apic via MSRs not via mmio.
278 If you don't know what to do here, say N.
281 bool "Support sparse irq numbering"
282 depends on PCI_MSI || HT_IRQ
284 This enables support for sparse irqs. This is useful for distro
285 kernels that want to define a high CONFIG_NR_CPUS value but still
286 want to have low kernel memory footprint on smaller machines.
288 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
289 out the irq_desc[] array in a more NUMA-friendly way. )
291 If you don't know what to do here, say N.
295 depends on SPARSE_IRQ && NUMA
298 bool "Enable MPS table" if ACPI
300 depends on X86_LOCAL_APIC
302 For old smp systems that do not have proper acpi support. Newer systems
303 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
306 bool "Support for big SMP systems with more than 8 CPUs"
307 depends on X86_32 && SMP
309 This option is needed for the systems that have more than 8 CPUs
312 config X86_EXTENDED_PLATFORM
313 bool "Support for extended (non-PC) x86 platforms"
316 If you disable this option then the kernel will only support
317 standard PC platforms. (which covers the vast majority of
320 If you enable this option then you'll be able to select support
321 for the following (non-PC) 32 bit x86 platforms:
325 SGI 320/540 (Visual Workstation)
326 Summit/EXA (IBM x440)
327 Unisys ES7000 IA32 series
329 If you have one of these systems, or if you want to build a
330 generic distribution kernel, say Y here - otherwise say N.
334 config X86_EXTENDED_PLATFORM
335 bool "Support for extended (non-PC) x86 platforms"
338 If you disable this option then the kernel will only support
339 standard PC platforms. (which covers the vast majority of
342 If you enable this option then you'll be able to select support
343 for the following (non-PC) 64 bit x86 platforms:
347 If you have one of these systems, or if you want to build a
348 generic distribution kernel, say Y here - otherwise say N.
350 # This is an alphabetically sorted list of 64 bit extended platforms
351 # Please maintain the alphabetic order if and when there are additions
356 depends on X86_64 && PCI
357 depends on X86_EXTENDED_PLATFORM
359 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
360 supposed to run on these EM64T-based machines. Only choose this option
361 if you have one of these machines.
364 bool "SGI Ultraviolet"
366 depends on X86_EXTENDED_PLATFORM
368 depends on X86_X2APIC
370 This option is needed in order to support SGI Ultraviolet systems.
371 If you don't have one of these, you should say N here.
373 # Following is an alphabetically sorted list of 32 bit extended platforms
374 # Please maintain the alphabetic order if and when there are additions
379 depends on X86_EXTENDED_PLATFORM
381 Select this for an AMD Elan processor.
383 Do not use this option for K6/Athlon/Opteron processors!
385 If unsure, choose "PC-compatible" instead.
388 bool "RDC R-321x SoC"
390 depends on X86_EXTENDED_PLATFORM
392 select X86_REBOOTFIXUPS
394 This option is needed for RDC R-321x system-on-chip, also known
396 If you don't have one of these chips, you should say N here.
398 config X86_32_NON_STANDARD
399 bool "Support non-standard 32-bit SMP architectures"
400 depends on X86_32 && SMP
401 depends on X86_EXTENDED_PLATFORM
403 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
404 subarchitectures. It is intended for a generic binary kernel.
405 if you select them all, kernel will probe it one by one. and will
408 # Alphabetically sorted list of Non standard 32 bit platforms
411 bool "NUMAQ (IBM/Sequent)"
412 depends on X86_32_NON_STANDARD
416 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
417 NUMA multiquad box. This changes the way that processors are
418 bootstrapped, and uses Clustered Logical APIC addressing mode instead
419 of Flat Logical. You will need a new lynxer.elf file to flash your
420 firmware with - send email to <Martin.Bligh@us.ibm.com>.
423 bool "SGI 320/540 (Visual Workstation)"
424 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
425 depends on X86_32_NON_STANDARD
427 The SGI Visual Workstation series is an IA32-based workstation
428 based on SGI systems chips with some legacy PC hardware attached.
430 Say Y here to create a kernel to run on the SGI 320 or 540.
432 A kernel compiled for the Visual Workstation will run on general
433 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
436 bool "Summit/EXA (IBM x440)"
437 depends on X86_32_NON_STANDARD
439 This option is needed for IBM systems that use the Summit/EXA chipset.
440 In particular, it is needed for the x440.
443 bool "Unisys ES7000 IA32 series"
444 depends on X86_32_NON_STANDARD && X86_BIGSMP
446 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
447 supposed to run on an IA32-based Unisys ES7000 system.
449 config SCHED_OMIT_FRAME_POINTER
451 prompt "Single-depth WCHAN output"
454 Calculate simpler /proc/<PID>/wchan values. If this option
455 is disabled then wchan values will recurse back to the
456 caller function. This provides more accurate wchan values,
457 at the expense of slightly more scheduling overhead.
459 If in doubt, say "Y".
461 menuconfig PARAVIRT_GUEST
462 bool "Paravirtualized guest support"
464 Say Y here to get to see options related to running Linux under
465 various hypervisors. This option alone does not add any kernel code.
467 If you say N, all options in this submenu will be skipped and disabled.
471 source "arch/x86/xen/Kconfig"
474 bool "VMI Guest support"
478 VMI provides a paravirtualized interface to the VMware ESX server
479 (it could be used by other hypervisors in theory too, but is not
480 at the moment), by linking the kernel to a GPL-ed ROM module
481 provided by the hypervisor.
484 bool "KVM paravirtualized clock"
486 select PARAVIRT_CLOCK
488 Turning on this option will allow you to run a paravirtualized clock
489 when running over the KVM hypervisor. Instead of relying on a PIT
490 (or probably other) emulation by the underlying device model, the host
491 provides the guest with timing infrastructure such as time of day, and
495 bool "KVM Guest support"
498 This option enables various optimizations for running under the KVM
501 source "arch/x86/lguest/Kconfig"
504 bool "Enable paravirtualization code"
506 This changes the kernel so it can modify itself when it is run
507 under a hypervisor, potentially improving performance significantly
508 over full virtualization. However, when run without a hypervisor
509 the kernel is theoretically slower and slightly larger.
511 config PARAVIRT_SPINLOCKS
512 bool "Paravirtualization layer for spinlocks"
513 depends on PARAVIRT && SMP && EXPERIMENTAL
515 Paravirtualized spinlocks allow a pvops backend to replace the
516 spinlock implementation with something virtualization-friendly
517 (for example, block the virtual CPU rather than spinning).
519 Unfortunately the downside is an up to 5% performance hit on
520 native kernels, with various workloads.
522 If you are unsure how to answer this question, answer N.
524 config PARAVIRT_CLOCK
530 config PARAVIRT_DEBUG
531 bool "paravirt-ops debugging"
532 depends on PARAVIRT && DEBUG_KERNEL
534 Enable to debug paravirt_ops internals. Specifically, BUG if
535 a paravirt_op is missing when it is called.
540 This option adds a kernel parameter 'memtest', which allows memtest
542 memtest=0, mean disabled; -- default
543 memtest=1, mean do 1 test pattern;
545 memtest=4, mean do 4 test patterns.
546 If you are unsure how to answer this question, answer N.
548 config X86_SUMMIT_NUMA
550 depends on X86_32 && NUMA && X86_32_NON_STANDARD
552 config X86_CYCLONE_TIMER
554 depends on X86_32_NON_STANDARD
556 source "arch/x86/Kconfig.cpu"
560 prompt "HPET Timer Support" if X86_32
562 Use the IA-PC HPET (High Precision Event Timer) to manage
563 time in preference to the PIT and RTC, if a HPET is
565 HPET is the next generation timer replacing legacy 8254s.
566 The HPET provides a stable time base on SMP
567 systems, unlike the TSC, but it is more expensive to access,
568 as it is off-chip. You can find the HPET spec at
569 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
571 You can safely choose Y here. However, HPET will only be
572 activated if the platform and the BIOS support this feature.
573 Otherwise the 8254 will be used for timing services.
575 Choose N to continue using the legacy 8254 timer.
577 config HPET_EMULATE_RTC
579 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
581 # Mark as embedded because too many people got it wrong.
582 # The code disables itself when not needed.
585 bool "Enable DMI scanning" if EMBEDDED
587 Enabled scanning of DMI to identify machine quirks. Say Y
588 here unless you have verified that your setup is not
589 affected by entries in the DMI blacklist. Required by PNP
593 bool "GART IOMMU support" if EMBEDDED
597 depends on X86_64 && PCI
599 Support for full DMA access of devices with 32bit memory access only
600 on systems with more than 3GB. This is usually needed for USB,
601 sound, many IDE/SATA chipsets and some other devices.
602 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
603 based hardware IOMMU and a software bounce buffer based IOMMU used
604 on Intel systems and as fallback.
605 The code is only active when needed (enough memory and limited
606 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
610 bool "IBM Calgary IOMMU support"
612 depends on X86_64 && PCI && EXPERIMENTAL
614 Support for hardware IOMMUs in IBM's xSeries x366 and x460
615 systems. Needed to run systems with more than 3GB of memory
616 properly with 32-bit PCI devices that do not support DAC
617 (Double Address Cycle). Calgary also supports bus level
618 isolation, where all DMAs pass through the IOMMU. This
619 prevents them from going anywhere except their intended
620 destination. This catches hard-to-find kernel bugs and
621 mis-behaving drivers and devices that do not use the DMA-API
622 properly to set up their DMA buffers. The IOMMU can be
623 turned off at boot time with the iommu=off parameter.
624 Normally the kernel will make the right choice by itself.
627 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
629 prompt "Should Calgary be enabled by default?"
630 depends on CALGARY_IOMMU
632 Should Calgary be enabled by default? if you choose 'y', Calgary
633 will be used (if it exists). If you choose 'n', Calgary will not be
634 used even if it exists. If you choose 'n' and would like to use
635 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
639 bool "AMD IOMMU support"
642 depends on X86_64 && PCI && ACPI
644 With this option you can enable support for AMD IOMMU hardware in
645 your system. An IOMMU is a hardware component which provides
646 remapping of DMA memory accesses from devices. With an AMD IOMMU you
647 can isolate the the DMA memory of different devices and protect the
648 system from misbehaving device drivers or hardware.
650 You can find out if your system has an AMD IOMMU if you look into
651 your BIOS for an option to enable it or if you have an IVRS ACPI
654 config AMD_IOMMU_STATS
655 bool "Export AMD IOMMU statistics to debugfs"
659 This option enables code in the AMD IOMMU driver to collect various
660 statistics about whats happening in the driver and exports that
661 information to userspace via debugfs.
664 # need this always selected by IOMMU for the VIA workaround
668 Support for software bounce buffers used on x86-64 systems
669 which don't have a hardware IOMMU (e.g. the current generation
670 of Intel's x86-64 CPUs). Using this PCI devices which can only
671 access 32-bits of memory can be used on systems with more than
672 3 GB of memory. If unsure, say Y.
675 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
678 def_bool (AMD_IOMMU || DMAR)
681 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
682 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
683 select CPUMASK_OFFSTACK
686 Configure maximum number of CPUS and NUMA Nodes for this architecture.
690 int "Maximum number of CPUs" if SMP && !MAXSMP
691 range 2 8 if SMP && X86_32 && !X86_BIGSMP
692 range 2 512 if SMP && !MAXSMP
694 default "4096" if MAXSMP
695 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
698 This allows you to specify the maximum number of CPUs which this
699 kernel will support. The maximum supported value is 512 and the
700 minimum value which makes sense is 2.
702 This is purely to save memory - each supported CPU adds
703 approximately eight kilobytes to the kernel image.
706 bool "SMT (Hyperthreading) scheduler support"
709 SMT scheduler support improves the CPU scheduler's decision making
710 when dealing with Intel Pentium 4 chips with HyperThreading at a
711 cost of slightly increased overhead in some places. If unsure say
716 prompt "Multi-core scheduler support"
719 Multi-core scheduler support improves the CPU scheduler's decision
720 making when dealing with multi-core CPU chips at a cost of slightly
721 increased overhead in some places. If unsure say N here.
723 source "kernel/Kconfig.preempt"
726 bool "Local APIC support on uniprocessors"
727 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
729 A local APIC (Advanced Programmable Interrupt Controller) is an
730 integrated interrupt controller in the CPU. If you have a single-CPU
731 system which has a processor with a local APIC, you can say Y here to
732 enable and use it. If you say Y here even though your machine doesn't
733 have a local APIC, then the kernel will still run with no slowdown at
734 all. The local APIC supports CPU-generated self-interrupts (timer,
735 performance counters), and the NMI watchdog which detects hard
739 bool "IO-APIC support on uniprocessors"
740 depends on X86_UP_APIC
742 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
743 SMP-capable replacement for PC-style interrupt controllers. Most
744 SMP systems and many recent uniprocessor systems have one.
746 If you have a single-CPU system with an IO-APIC, you can say Y here
747 to use it. If you say Y here even though your machine doesn't have
748 an IO-APIC, then the kernel will still run with no slowdown at all.
750 config X86_LOCAL_APIC
752 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
756 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
758 config X86_VISWS_APIC
760 depends on X86_32 && X86_VISWS
762 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
763 bool "Reroute for broken boot IRQs"
765 depends on X86_IO_APIC
767 This option enables a workaround that fixes a source of
768 spurious interrupts. This is recommended when threaded
769 interrupt handling is used on systems where the generation of
770 superfluous "boot interrupts" cannot be disabled.
772 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
773 entry in the chipset's IO-APIC is masked (as, e.g. the RT
774 kernel does during interrupt handling). On chipsets where this
775 boot IRQ generation cannot be disabled, this workaround keeps
776 the original IRQ line masked so that only the equivalent "boot
777 IRQ" is delivered to the CPUs. The workaround also tells the
778 kernel to set up the IRQ handler on the boot IRQ line. In this
779 way only one interrupt is delivered to the kernel. Otherwise
780 the spurious second interrupt may cause the kernel to bring
781 down (vital) interrupt lines.
783 Only affects "broken" chipsets. Interrupt sharing may be
784 increased on these systems.
787 bool "Machine Check Exception"
789 Machine Check Exception support allows the processor to notify the
790 kernel if it detects a problem (e.g. overheating, component failure).
791 The action the kernel takes depends on the severity of the problem,
792 ranging from a warning message on the console, to halting the machine.
793 Your processor must be a Pentium or newer to support this - check the
794 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
795 have a design flaw which leads to false MCE events - hence MCE is
796 disabled on all P5 processors, unless explicitly enabled with "mce"
797 as a boot argument. Similarly, if MCE is built in and creates a
798 problem on some new non-standard machine, you can boot with "nomce"
799 to disable it. MCE support simply ignores non-MCE processors like
800 the 386 and 486, so nearly everyone can say Y here.
803 depends on X86_32 && X86_MCE
804 bool "Use legacy machine check code (will go away)"
806 select X86_ANCIENT_MCE
808 Use the old i386 machine check code. This is merely intended for
809 testing in a transition period. Try this if you run into any machine
810 check related software problems, but report the problem to
811 linux-kernel. When in doubt say no.
816 default y if (!X86_OLD_MCE && X86_32) || X86_64
820 prompt "Intel MCE features"
821 depends on X86_NEW_MCE && X86_LOCAL_APIC
823 Additional support for intel specific MCE features such as
828 prompt "AMD MCE features"
829 depends on X86_NEW_MCE && X86_LOCAL_APIC
831 Additional support for AMD specific MCE features such as
832 the DRAM Error Threshold.
834 config X86_ANCIENT_MCE
837 prompt "Support for old Pentium 5 / WinChip machine checks"
839 Include support for machine check handling on old Pentium 5 or WinChip
840 systems. These typically need to be enabled explicitely on the command
843 config X86_MCE_THRESHOLD
844 depends on X86_MCE_AMD || X86_MCE_INTEL
848 config X86_MCE_INJECT
849 depends on X86_NEW_MCE
850 tristate "Machine check injector support"
852 Provide support for injecting machine checks for testing purposes.
853 If you don't know what a machine check is and you don't do kernel
854 QA it is safe to say n.
856 config X86_MCE_NONFATAL
857 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
858 depends on X86_OLD_MCE
860 Enabling this feature starts a timer that triggers every 5 seconds which
861 will look at the machine check registers to see if anything happened.
862 Non-fatal problems automatically get corrected (but still logged).
863 Disable this if you don't want to see these messages.
864 Seeing the messages this option prints out may be indicative of dying
865 or out-of-spec (ie, overclocked) hardware.
866 This option only does something on certain CPUs.
867 (AMD Athlon/Duron and Intel Pentium 4)
869 config X86_MCE_P4THERMAL
870 bool "check for P4 thermal throttling interrupt."
871 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
873 Enabling this feature will cause a message to be printed when the P4
874 enters thermal throttling.
876 config X86_THERMAL_VECTOR
878 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
881 bool "Enable VM86 support" if EMBEDDED
885 This option is required by programs like DOSEMU to run 16-bit legacy
886 code on X86 processors. It also may be needed by software like
887 XFree86 to initialize some video cards via BIOS. Disabling this
888 option saves about 6k.
891 tristate "Toshiba Laptop support"
894 This adds a driver to safely access the System Management Mode of
895 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
896 not work on models with a Phoenix BIOS. The System Management Mode
897 is used to set the BIOS and power saving options on Toshiba portables.
899 For information on utilities to make use of this driver see the
900 Toshiba Linux utilities web site at:
901 <http://www.buzzard.org.uk/toshiba/>.
903 Say Y if you intend to run this kernel on a Toshiba portable.
907 tristate "Dell laptop support"
909 This adds a driver to safely access the System Management Mode
910 of the CPU on the Dell Inspiron 8000. The System Management Mode
911 is used to read cpu temperature and cooling fan status and to
912 control the fans on the I8K portables.
914 This driver has been tested only on the Inspiron 8000 but it may
915 also work with other Dell laptops. You can force loading on other
916 models by passing the parameter `force=1' to the module. Use at
919 For information on utilities to make use of this driver see the
920 I8K Linux utilities web site at:
921 <http://people.debian.org/~dz/i8k/>
923 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
926 config X86_REBOOTFIXUPS
927 bool "Enable X86 board specific fixups for reboot"
930 This enables chipset and/or board specific fixups to be done
931 in order to get reboot to work correctly. This is only needed on
932 some combinations of hardware and BIOS. The symptom, for which
933 this config is intended, is when reboot ends with a stalled/hung
936 Currently, the only fixup is for the Geode machines using
937 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
939 Say Y if you want to enable the fixup. Currently, it's safe to
940 enable this option even if you don't need it.
944 tristate "/dev/cpu/microcode - microcode support"
947 If you say Y here, you will be able to update the microcode on
948 certain Intel and AMD processors. The Intel support is for the
949 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
950 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
951 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
952 You will obviously need the actual microcode binary data itself
953 which is not shipped with the Linux kernel.
955 This option selects the general module only, you need to select
956 at least one vendor specific module as well.
958 To compile this driver as a module, choose M here: the
959 module will be called microcode.
961 config MICROCODE_INTEL
962 bool "Intel microcode patch loading support"
967 This options enables microcode patch loading support for Intel
970 For latest news and information on obtaining all the required
971 Intel ingredients for this driver, check:
972 <http://www.urbanmyth.org/microcode/>.
975 bool "AMD microcode patch loading support"
979 If you select this option, microcode patch loading support for AMD
980 processors will be enabled.
982 config MICROCODE_OLD_INTERFACE
987 tristate "/dev/cpu/*/msr - Model-specific register support"
989 This device gives privileged processes access to the x86
990 Model-Specific Registers (MSRs). It is a character device with
991 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
992 MSR accesses are directed to a specific CPU on multi-processor
996 tristate "/dev/cpu/*/cpuid - CPU information support"
998 This device gives processes access to the x86 CPUID instruction to
999 be executed on a specific processor. It is a character device
1000 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1003 config X86_CPU_DEBUG
1004 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
1006 If you select this option, this will provide various x86 CPUs
1007 information through debugfs.
1010 prompt "High Memory Support"
1011 default HIGHMEM4G if !X86_NUMAQ
1012 default HIGHMEM64G if X86_NUMAQ
1017 depends on !X86_NUMAQ
1019 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1020 However, the address space of 32-bit x86 processors is only 4
1021 Gigabytes large. That means that, if you have a large amount of
1022 physical memory, not all of it can be "permanently mapped" by the
1023 kernel. The physical memory that's not permanently mapped is called
1026 If you are compiling a kernel which will never run on a machine with
1027 more than 1 Gigabyte total physical RAM, answer "off" here (default
1028 choice and suitable for most users). This will result in a "3GB/1GB"
1029 split: 3GB are mapped so that each process sees a 3GB virtual memory
1030 space and the remaining part of the 4GB virtual memory space is used
1031 by the kernel to permanently map as much physical memory as
1034 If the machine has between 1 and 4 Gigabytes physical RAM, then
1037 If more than 4 Gigabytes is used then answer "64GB" here. This
1038 selection turns Intel PAE (Physical Address Extension) mode on.
1039 PAE implements 3-level paging on IA32 processors. PAE is fully
1040 supported by Linux, PAE mode is implemented on all recent Intel
1041 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1042 then the kernel will not boot on CPUs that don't support PAE!
1044 The actual amount of total physical memory will either be
1045 auto detected or can be forced by using a kernel command line option
1046 such as "mem=256M". (Try "man bootparam" or see the documentation of
1047 your boot loader (lilo or loadlin) about how to pass options to the
1048 kernel at boot time.)
1050 If unsure, say "off".
1054 depends on !X86_NUMAQ
1056 Select this if you have a 32-bit processor and between 1 and 4
1057 gigabytes of physical RAM.
1061 depends on !M386 && !M486
1064 Select this if you have a 32-bit processor and more than 4
1065 gigabytes of physical RAM.
1070 depends on EXPERIMENTAL
1071 prompt "Memory split" if EMBEDDED
1075 Select the desired split between kernel and user memory.
1077 If the address range available to the kernel is less than the
1078 physical memory installed, the remaining memory will be available
1079 as "high memory". Accessing high memory is a little more costly
1080 than low memory, as it needs to be mapped into the kernel first.
1081 Note that increasing the kernel address space limits the range
1082 available to user programs, making the address space there
1083 tighter. Selecting anything other than the default 3G/1G split
1084 will also likely make your kernel incompatible with binary-only
1087 If you are not absolutely sure what you are doing, leave this
1091 bool "3G/1G user/kernel split"
1092 config VMSPLIT_3G_OPT
1094 bool "3G/1G user/kernel split (for full 1G low memory)"
1096 bool "2G/2G user/kernel split"
1097 config VMSPLIT_2G_OPT
1099 bool "2G/2G user/kernel split (for full 2G low memory)"
1101 bool "1G/3G user/kernel split"
1106 default 0xB0000000 if VMSPLIT_3G_OPT
1107 default 0x80000000 if VMSPLIT_2G
1108 default 0x78000000 if VMSPLIT_2G_OPT
1109 default 0x40000000 if VMSPLIT_1G
1115 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1118 bool "PAE (Physical Address Extension) Support"
1119 depends on X86_32 && !HIGHMEM4G
1121 PAE is required for NX support, and furthermore enables
1122 larger swapspace support for non-overcommit purposes. It
1123 has the cost of more pagetable lookup overhead, and also
1124 consumes more pagetable space per process.
1126 config ARCH_PHYS_ADDR_T_64BIT
1127 def_bool X86_64 || X86_PAE
1129 config DIRECT_GBPAGES
1130 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1134 Allow the kernel linear mapping to use 1GB pages on CPUs that
1135 support it. This can improve the kernel's performance a tiny bit by
1136 reducing TLB pressure. If in doubt, say "Y".
1138 # Common NUMA Features
1140 bool "Numa Memory Allocation and Scheduler Support"
1142 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1143 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1145 Enable NUMA (Non Uniform Memory Access) support.
1147 The kernel will try to allocate memory used by a CPU on the
1148 local memory controller of the CPU and add some more
1149 NUMA awareness to the kernel.
1151 For 64-bit this is recommended if the system is Intel Core i7
1152 (or later), AMD Opteron, or EM64T NUMA.
1154 For 32-bit this is only needed on (rare) 32-bit-only platforms
1155 that support NUMA topologies, such as NUMAQ / Summit, or if you
1156 boot a 32-bit kernel on a 64-bit NUMA platform.
1158 Otherwise, you should say N.
1160 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1161 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1165 prompt "Old style AMD Opteron NUMA detection"
1166 depends on X86_64 && NUMA && PCI
1168 Enable K8 NUMA node topology detection. You should say Y here if
1169 you have a multi processor AMD K8 system. This uses an old
1170 method to read the NUMA configuration directly from the builtin
1171 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1172 instead, which also takes priority if both are compiled in.
1174 config X86_64_ACPI_NUMA
1176 prompt "ACPI NUMA detection"
1177 depends on X86_64 && NUMA && ACPI && PCI
1180 Enable ACPI SRAT based node topology detection.
1182 # Some NUMA nodes have memory ranges that span
1183 # other nodes. Even though a pfn is valid and
1184 # between a node's start and end pfns, it may not
1185 # reside on that node. See memmap_init_zone()
1187 config NODES_SPAN_OTHER_NODES
1189 depends on X86_64_ACPI_NUMA
1192 bool "NUMA emulation"
1193 depends on X86_64 && NUMA
1195 Enable NUMA emulation. A flat machine will be split
1196 into virtual nodes when booted with "numa=fake=N", where N is the
1197 number of nodes. This is only useful for debugging.
1200 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1202 default "9" if MAXSMP
1203 default "6" if X86_64
1204 default "4" if X86_NUMAQ
1206 depends on NEED_MULTIPLE_NODES
1208 Specify the maximum number of NUMA Nodes available on the target
1209 system. Increases memory reserved to accommodate various tables.
1211 config HAVE_ARCH_BOOTMEM
1213 depends on X86_32 && NUMA
1215 config ARCH_HAVE_MEMORY_PRESENT
1217 depends on X86_32 && DISCONTIGMEM
1219 config NEED_NODE_MEMMAP_SIZE
1221 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1223 config HAVE_ARCH_ALLOC_REMAP
1225 depends on X86_32 && NUMA
1227 config ARCH_FLATMEM_ENABLE
1229 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1231 config ARCH_DISCONTIGMEM_ENABLE
1233 depends on NUMA && X86_32
1235 config ARCH_DISCONTIGMEM_DEFAULT
1237 depends on NUMA && X86_32
1239 config ARCH_SPARSEMEM_DEFAULT
1243 config ARCH_SPARSEMEM_ENABLE
1245 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1246 select SPARSEMEM_STATIC if X86_32
1247 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1249 config ARCH_SELECT_MEMORY_MODEL
1251 depends on ARCH_SPARSEMEM_ENABLE
1253 config ARCH_MEMORY_PROBE
1255 depends on MEMORY_HOTPLUG
1260 bool "Allocate 3rd-level pagetables from highmem"
1261 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1263 The VM uses one page table entry for each page of physical memory.
1264 For systems with a lot of RAM, this can be wasteful of precious
1265 low memory. Setting this option will put user-space page table
1266 entries in high memory.
1268 config X86_CHECK_BIOS_CORRUPTION
1269 bool "Check for low memory corruption"
1271 Periodically check for memory corruption in low memory, which
1272 is suspected to be caused by BIOS. Even when enabled in the
1273 configuration, it is disabled at runtime. Enable it by
1274 setting "memory_corruption_check=1" on the kernel command
1275 line. By default it scans the low 64k of memory every 60
1276 seconds; see the memory_corruption_check_size and
1277 memory_corruption_check_period parameters in
1278 Documentation/kernel-parameters.txt to adjust this.
1280 When enabled with the default parameters, this option has
1281 almost no overhead, as it reserves a relatively small amount
1282 of memory and scans it infrequently. It both detects corruption
1283 and prevents it from affecting the running system.
1285 It is, however, intended as a diagnostic tool; if repeatable
1286 BIOS-originated corruption always affects the same memory,
1287 you can use memmap= to prevent the kernel from using that
1290 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1291 bool "Set the default setting of memory_corruption_check"
1292 depends on X86_CHECK_BIOS_CORRUPTION
1295 Set whether the default state of memory_corruption_check is
1298 config X86_RESERVE_LOW_64K
1299 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1302 Reserve the first 64K of physical RAM on BIOSes that are known
1303 to potentially corrupt that memory range. A numbers of BIOSes are
1304 known to utilize this area during suspend/resume, so it must not
1305 be used by the kernel.
1307 Set this to N if you are absolutely sure that you trust the BIOS
1308 to get all its memory reservations and usages right.
1310 If you have doubts about the BIOS (e.g. suspend/resume does not
1311 work or there's kernel crashes after certain hardware hotplug
1312 events) and it's not AMI or Phoenix, then you might want to enable
1313 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1314 corruption patterns.
1318 config MATH_EMULATION
1320 prompt "Math emulation" if X86_32
1322 Linux can emulate a math coprocessor (used for floating point
1323 operations) if you don't have one. 486DX and Pentium processors have
1324 a math coprocessor built in, 486SX and 386 do not, unless you added
1325 a 487DX or 387, respectively. (The messages during boot time can
1326 give you some hints here ["man dmesg"].) Everyone needs either a
1327 coprocessor or this emulation.
1329 If you don't have a math coprocessor, you need to say Y here; if you
1330 say Y here even though you have a coprocessor, the coprocessor will
1331 be used nevertheless. (This behavior can be changed with the kernel
1332 command line option "no387", which comes handy if your coprocessor
1333 is broken. Try "man bootparam" or see the documentation of your boot
1334 loader (lilo or loadlin) about how to pass options to the kernel at
1335 boot time.) This means that it is a good idea to say Y here if you
1336 intend to use this kernel on different machines.
1338 More information about the internals of the Linux math coprocessor
1339 emulation can be found in <file:arch/x86/math-emu/README>.
1341 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1342 kernel, it won't hurt.
1345 bool "MTRR (Memory Type Range Register) support"
1347 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1348 the Memory Type Range Registers (MTRRs) may be used to control
1349 processor access to memory ranges. This is most useful if you have
1350 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1351 allows bus write transfers to be combined into a larger transfer
1352 before bursting over the PCI/AGP bus. This can increase performance
1353 of image write operations 2.5 times or more. Saying Y here creates a
1354 /proc/mtrr file which may be used to manipulate your processor's
1355 MTRRs. Typically the X server should use this.
1357 This code has a reasonably generic interface so that similar
1358 control registers on other processors can be easily supported
1361 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1362 Registers (ARRs) which provide a similar functionality to MTRRs. For
1363 these, the ARRs are used to emulate the MTRRs.
1364 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1365 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1366 write-combining. All of these processors are supported by this code
1367 and it makes sense to say Y here if you have one of them.
1369 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1370 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1371 can lead to all sorts of problems, so it's good to say Y here.
1373 You can safely say Y even if your machine doesn't have MTRRs, you'll
1374 just add about 9 KB to your kernel.
1376 See <file:Documentation/x86/mtrr.txt> for more information.
1378 config MTRR_SANITIZER
1380 prompt "MTRR cleanup support"
1383 Convert MTRR layout from continuous to discrete, so X drivers can
1384 add writeback entries.
1386 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1387 The largest mtrr entry size for a continuous block can be set with
1392 config MTRR_SANITIZER_ENABLE_DEFAULT
1393 int "MTRR cleanup enable value (0-1)"
1396 depends on MTRR_SANITIZER
1398 Enable mtrr cleanup default value
1400 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1401 int "MTRR cleanup spare reg num (0-7)"
1404 depends on MTRR_SANITIZER
1406 mtrr cleanup spare entries default, it can be changed via
1407 mtrr_spare_reg_nr=N on the kernel command line.
1411 prompt "x86 PAT support"
1414 Use PAT attributes to setup page level cache control.
1416 PATs are the modern equivalents of MTRRs and are much more
1417 flexible than MTRRs.
1419 Say N here if you see bootup problems (boot crash, boot hang,
1420 spontaneous reboots) or a non-working video driver.
1425 bool "EFI runtime service support"
1428 This enables the kernel to use EFI runtime services that are
1429 available (such as the EFI variable services).
1431 This option is only useful on systems that have EFI firmware.
1432 In addition, you should use the latest ELILO loader available
1433 at <http://elilo.sourceforge.net> in order to take advantage
1434 of EFI runtime services. However, even with this option, the
1435 resultant kernel should continue to boot on existing non-EFI
1440 prompt "Enable seccomp to safely compute untrusted bytecode"
1442 This kernel feature is useful for number crunching applications
1443 that may need to compute untrusted bytecode during their
1444 execution. By using pipes or other transports made available to
1445 the process as file descriptors supporting the read/write
1446 syscalls, it's possible to isolate those applications in
1447 their own address space using seccomp. Once seccomp is
1448 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1449 and the task is only allowed to execute a few safe syscalls
1450 defined by each seccomp mode.
1452 If unsure, say Y. Only embedded should say N here.
1454 config CC_STACKPROTECTOR_ALL
1457 config CC_STACKPROTECTOR
1458 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1459 select CC_STACKPROTECTOR_ALL
1461 This option turns on the -fstack-protector GCC feature. This
1462 feature puts, at the beginning of functions, a canary value on
1463 the stack just before the return address, and validates
1464 the value just before actually returning. Stack based buffer
1465 overflows (that need to overwrite this return address) now also
1466 overwrite the canary, which gets detected and the attack is then
1467 neutralized via a kernel panic.
1469 This feature requires gcc version 4.2 or above, or a distribution
1470 gcc with the feature backported. Older versions are automatically
1471 detected and for those versions, this configuration option is
1472 ignored. (and a warning is printed during bootup)
1474 source kernel/Kconfig.hz
1477 bool "kexec system call"
1479 kexec is a system call that implements the ability to shutdown your
1480 current kernel, and to start another kernel. It is like a reboot
1481 but it is independent of the system firmware. And like a reboot
1482 you can start any kernel with it, not just Linux.
1484 The name comes from the similarity to the exec system call.
1486 It is an ongoing process to be certain the hardware in a machine
1487 is properly shutdown, so do not be surprised if this code does not
1488 initially work for you. It may help to enable device hotplugging
1489 support. As of this writing the exact hardware interface is
1490 strongly in flux, so no good recommendation can be made.
1493 bool "kernel crash dumps"
1494 depends on X86_64 || (X86_32 && HIGHMEM)
1496 Generate crash dump after being started by kexec.
1497 This should be normally only set in special crash dump kernels
1498 which are loaded in the main kernel with kexec-tools into
1499 a specially reserved region and then later executed after
1500 a crash by kdump/kexec. The crash dump kernel must be compiled
1501 to a memory address not used by the main kernel or BIOS using
1502 PHYSICAL_START, or it must be built as a relocatable image
1503 (CONFIG_RELOCATABLE=y).
1504 For more details see Documentation/kdump/kdump.txt
1507 bool "kexec jump (EXPERIMENTAL)"
1508 depends on EXPERIMENTAL
1509 depends on KEXEC && HIBERNATION
1511 Jump between original kernel and kexeced kernel and invoke
1512 code in physical address mode via KEXEC
1514 config PHYSICAL_START
1515 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1518 This gives the physical address where the kernel is loaded.
1520 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1521 bzImage will decompress itself to above physical address and
1522 run from there. Otherwise, bzImage will run from the address where
1523 it has been loaded by the boot loader and will ignore above physical
1526 In normal kdump cases one does not have to set/change this option
1527 as now bzImage can be compiled as a completely relocatable image
1528 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1529 address. This option is mainly useful for the folks who don't want
1530 to use a bzImage for capturing the crash dump and want to use a
1531 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1532 to be specifically compiled to run from a specific memory area
1533 (normally a reserved region) and this option comes handy.
1535 So if you are using bzImage for capturing the crash dump,
1536 leave the value here unchanged to 0x1000000 and set
1537 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1538 for capturing the crash dump change this value to start of
1539 the reserved region. In other words, it can be set based on
1540 the "X" value as specified in the "crashkernel=YM@XM"
1541 command line boot parameter passed to the panic-ed
1542 kernel. Please take a look at Documentation/kdump/kdump.txt
1543 for more details about crash dumps.
1545 Usage of bzImage for capturing the crash dump is recommended as
1546 one does not have to build two kernels. Same kernel can be used
1547 as production kernel and capture kernel. Above option should have
1548 gone away after relocatable bzImage support is introduced. But it
1549 is present because there are users out there who continue to use
1550 vmlinux for dump capture. This option should go away down the
1553 Don't change this unless you know what you are doing.
1556 bool "Build a relocatable kernel"
1559 This builds a kernel image that retains relocation information
1560 so it can be loaded someplace besides the default 1MB.
1561 The relocations tend to make the kernel binary about 10% larger,
1562 but are discarded at runtime.
1564 One use is for the kexec on panic case where the recovery kernel
1565 must live at a different physical address than the primary
1568 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1569 it has been loaded at and the compile time physical address
1570 (CONFIG_PHYSICAL_START) is ignored.
1572 # Relocation on x86-32 needs some additional build support
1573 config X86_NEED_RELOCS
1575 depends on X86_32 && RELOCATABLE
1577 config PHYSICAL_ALIGN
1579 prompt "Alignment value to which kernel should be aligned" if X86_32
1581 range 0x2000 0x1000000
1583 This value puts the alignment restrictions on physical address
1584 where kernel is loaded and run from. Kernel is compiled for an
1585 address which meets above alignment restriction.
1587 If bootloader loads the kernel at a non-aligned address and
1588 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1589 address aligned to above value and run from there.
1591 If bootloader loads the kernel at a non-aligned address and
1592 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1593 load address and decompress itself to the address it has been
1594 compiled for and run from there. The address for which kernel is
1595 compiled already meets above alignment restrictions. Hence the
1596 end result is that kernel runs from a physical address meeting
1597 above alignment restrictions.
1599 Don't change this unless you know what you are doing.
1602 bool "Support for hot-pluggable CPUs"
1603 depends on SMP && HOTPLUG
1605 Say Y here to allow turning CPUs off and on. CPUs can be
1606 controlled through /sys/devices/system/cpu.
1607 ( Note: power management support will enable this option
1608 automatically on SMP systems. )
1609 Say N if you want to disable CPU hotplug.
1613 prompt "Compat VDSO support"
1614 depends on X86_32 || IA32_EMULATION
1616 Map the 32-bit VDSO to the predictable old-style address too.
1618 Say N here if you are running a sufficiently recent glibc
1619 version (2.3.3 or later), to remove the high-mapped
1620 VDSO mapping and to exclusively use the randomized VDSO.
1625 bool "Built-in kernel command line"
1628 Allow for specifying boot arguments to the kernel at
1629 build time. On some systems (e.g. embedded ones), it is
1630 necessary or convenient to provide some or all of the
1631 kernel boot arguments with the kernel itself (that is,
1632 to not rely on the boot loader to provide them.)
1634 To compile command line arguments into the kernel,
1635 set this option to 'Y', then fill in the
1636 the boot arguments in CONFIG_CMDLINE.
1638 Systems with fully functional boot loaders (i.e. non-embedded)
1639 should leave this option set to 'N'.
1642 string "Built-in kernel command string"
1643 depends on CMDLINE_BOOL
1646 Enter arguments here that should be compiled into the kernel
1647 image and used at boot time. If the boot loader provides a
1648 command line at boot time, it is appended to this string to
1649 form the full kernel command line, when the system boots.
1651 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1652 change this behavior.
1654 In most cases, the command line (whether built-in or provided
1655 by the boot loader) should specify the device for the root
1658 config CMDLINE_OVERRIDE
1659 bool "Built-in command line overrides boot loader arguments"
1661 depends on CMDLINE_BOOL
1663 Set this option to 'Y' to have the kernel ignore the boot loader
1664 command line, and use ONLY the built-in command line.
1666 This is used to work around broken boot loaders. This should
1667 be set to 'N' under normal conditions.
1671 config ARCH_ENABLE_MEMORY_HOTPLUG
1673 depends on X86_64 || (X86_32 && HIGHMEM)
1675 config ARCH_ENABLE_MEMORY_HOTREMOVE
1677 depends on MEMORY_HOTPLUG
1679 config HAVE_ARCH_EARLY_PFN_TO_NID
1683 menu "Power management and ACPI options"
1685 config ARCH_HIBERNATION_HEADER
1687 depends on X86_64 && HIBERNATION
1689 source "kernel/power/Kconfig"
1691 source "drivers/acpi/Kconfig"
1696 depends on APM || APM_MODULE
1699 tristate "APM (Advanced Power Management) BIOS support"
1700 depends on X86_32 && PM_SLEEP
1702 APM is a BIOS specification for saving power using several different
1703 techniques. This is mostly useful for battery powered laptops with
1704 APM compliant BIOSes. If you say Y here, the system time will be
1705 reset after a RESUME operation, the /proc/apm device will provide
1706 battery status information, and user-space programs will receive
1707 notification of APM "events" (e.g. battery status change).
1709 If you select "Y" here, you can disable actual use of the APM
1710 BIOS by passing the "apm=off" option to the kernel at boot time.
1712 Note that the APM support is almost completely disabled for
1713 machines with more than one CPU.
1715 In order to use APM, you will need supporting software. For location
1716 and more information, read <file:Documentation/power/pm.txt> and the
1717 Battery Powered Linux mini-HOWTO, available from
1718 <http://www.tldp.org/docs.html#howto>.
1720 This driver does not spin down disk drives (see the hdparm(8)
1721 manpage ("man 8 hdparm") for that), and it doesn't turn off
1722 VESA-compliant "green" monitors.
1724 This driver does not support the TI 4000M TravelMate and the ACER
1725 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1726 desktop machines also don't have compliant BIOSes, and this driver
1727 may cause those machines to panic during the boot phase.
1729 Generally, if you don't have a battery in your machine, there isn't
1730 much point in using this driver and you should say N. If you get
1731 random kernel OOPSes or reboots that don't seem to be related to
1732 anything, try disabling/enabling this option (or disabling/enabling
1735 Some other things you should try when experiencing seemingly random,
1738 1) make sure that you have enough swap space and that it is
1740 2) pass the "no-hlt" option to the kernel
1741 3) switch on floating point emulation in the kernel and pass
1742 the "no387" option to the kernel
1743 4) pass the "floppy=nodma" option to the kernel
1744 5) pass the "mem=4M" option to the kernel (thereby disabling
1745 all but the first 4 MB of RAM)
1746 6) make sure that the CPU is not over clocked.
1747 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1748 8) disable the cache from your BIOS settings
1749 9) install a fan for the video card or exchange video RAM
1750 10) install a better fan for the CPU
1751 11) exchange RAM chips
1752 12) exchange the motherboard.
1754 To compile this driver as a module, choose M here: the
1755 module will be called apm.
1759 config APM_IGNORE_USER_SUSPEND
1760 bool "Ignore USER SUSPEND"
1762 This option will ignore USER SUSPEND requests. On machines with a
1763 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1764 series notebooks, it is necessary to say Y because of a BIOS bug.
1766 config APM_DO_ENABLE
1767 bool "Enable PM at boot time"
1769 Enable APM features at boot time. From page 36 of the APM BIOS
1770 specification: "When disabled, the APM BIOS does not automatically
1771 power manage devices, enter the Standby State, enter the Suspend
1772 State, or take power saving steps in response to CPU Idle calls."
1773 This driver will make CPU Idle calls when Linux is idle (unless this
1774 feature is turned off -- see "Do CPU IDLE calls", below). This
1775 should always save battery power, but more complicated APM features
1776 will be dependent on your BIOS implementation. You may need to turn
1777 this option off if your computer hangs at boot time when using APM
1778 support, or if it beeps continuously instead of suspending. Turn
1779 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1780 T400CDT. This is off by default since most machines do fine without
1784 bool "Make CPU Idle calls when idle"
1786 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1787 On some machines, this can activate improved power savings, such as
1788 a slowed CPU clock rate, when the machine is idle. These idle calls
1789 are made after the idle loop has run for some length of time (e.g.,
1790 333 mS). On some machines, this will cause a hang at boot time or
1791 whenever the CPU becomes idle. (On machines with more than one CPU,
1792 this option does nothing.)
1794 config APM_DISPLAY_BLANK
1795 bool "Enable console blanking using APM"
1797 Enable console blanking using the APM. Some laptops can use this to
1798 turn off the LCD backlight when the screen blanker of the Linux
1799 virtual console blanks the screen. Note that this is only used by
1800 the virtual console screen blanker, and won't turn off the backlight
1801 when using the X Window system. This also doesn't have anything to
1802 do with your VESA-compliant power-saving monitor. Further, this
1803 option doesn't work for all laptops -- it might not turn off your
1804 backlight at all, or it might print a lot of errors to the console,
1805 especially if you are using gpm.
1807 config APM_ALLOW_INTS
1808 bool "Allow interrupts during APM BIOS calls"
1810 Normally we disable external interrupts while we are making calls to
1811 the APM BIOS as a measure to lessen the effects of a badly behaving
1812 BIOS implementation. The BIOS should reenable interrupts if it
1813 needs to. Unfortunately, some BIOSes do not -- especially those in
1814 many of the newer IBM Thinkpads. If you experience hangs when you
1815 suspend, try setting this to Y. Otherwise, say N.
1819 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1821 source "drivers/cpuidle/Kconfig"
1823 source "drivers/idle/Kconfig"
1828 menu "Bus options (PCI etc.)"
1833 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1835 Find out whether you have a PCI motherboard. PCI is the name of a
1836 bus system, i.e. the way the CPU talks to the other stuff inside
1837 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1838 VESA. If you have PCI, say Y, otherwise N.
1841 prompt "PCI access mode"
1842 depends on X86_32 && PCI
1845 On PCI systems, the BIOS can be used to detect the PCI devices and
1846 determine their configuration. However, some old PCI motherboards
1847 have BIOS bugs and may crash if this is done. Also, some embedded
1848 PCI-based systems don't have any BIOS at all. Linux can also try to
1849 detect the PCI hardware directly without using the BIOS.
1851 With this option, you can specify how Linux should detect the
1852 PCI devices. If you choose "BIOS", the BIOS will be used,
1853 if you choose "Direct", the BIOS won't be used, and if you
1854 choose "MMConfig", then PCI Express MMCONFIG will be used.
1855 If you choose "Any", the kernel will try MMCONFIG, then the
1856 direct access method and falls back to the BIOS if that doesn't
1857 work. If unsure, go with the default, which is "Any".
1862 config PCI_GOMMCONFIG
1879 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1881 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1884 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1888 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1892 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1899 bool "Support mmconfig PCI config space access"
1900 depends on X86_64 && PCI && ACPI
1903 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1904 depends on PCI_MSI && ACPI && EXPERIMENTAL
1906 DMA remapping (DMAR) devices support enables independent address
1907 translations for Direct Memory Access (DMA) from devices.
1908 These DMA remapping devices are reported via ACPI tables
1909 and include PCI device scope covered by these DMA
1912 config DMAR_DEFAULT_ON
1914 prompt "Enable DMA Remapping Devices by default"
1917 Selecting this option will enable a DMAR device at boot time if
1918 one is found. If this option is not selected, DMAR support can
1919 be enabled by passing intel_iommu=on to the kernel. It is
1920 recommended you say N here while the DMAR code remains
1923 config DMAR_BROKEN_GFX_WA
1925 prompt "Workaround broken graphics drivers (going away soon)"
1928 Current Graphics drivers tend to use physical address
1929 for DMA and avoid using DMA APIs. Setting this config
1930 option permits the IOMMU driver to set a unity map for
1931 all the OS-visible memory. Hence the driver can continue
1932 to use physical addresses for DMA, at least until this
1933 option is removed in the 2.6.32 kernel.
1935 config DMAR_FLOPPY_WA
1939 Floppy disk drivers are known to bypass DMA API calls
1940 thereby failing to work when IOMMU is enabled. This
1941 workaround will setup a 1:1 mapping for the first
1942 16MiB to make floppy (an ISA device) work.
1945 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1946 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1948 Supports Interrupt remapping for IO-APIC and MSI devices.
1949 To use x2apic mode in the CPU's which support x2APIC enhancements or
1950 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1952 source "drivers/pci/pcie/Kconfig"
1954 source "drivers/pci/Kconfig"
1956 # x86_64 have no ISA slots, but do have ISA-style DMA.
1965 Find out whether you have ISA slots on your motherboard. ISA is the
1966 name of a bus system, i.e. the way the CPU talks to the other stuff
1967 inside your box. Other bus systems are PCI, EISA, MicroChannel
1968 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1969 newer boards don't support it. If you have ISA, say Y, otherwise N.
1975 The Extended Industry Standard Architecture (EISA) bus was
1976 developed as an open alternative to the IBM MicroChannel bus.
1978 The EISA bus provided some of the features of the IBM MicroChannel
1979 bus while maintaining backward compatibility with cards made for
1980 the older ISA bus. The EISA bus saw limited use between 1988 and
1981 1995 when it was made obsolete by the PCI bus.
1983 Say Y here if you are building a kernel for an EISA-based machine.
1987 source "drivers/eisa/Kconfig"
1992 MicroChannel Architecture is found in some IBM PS/2 machines and
1993 laptops. It is a bus system similar to PCI or ISA. See
1994 <file:Documentation/mca.txt> (and especially the web page given
1995 there) before attempting to build an MCA bus kernel.
1997 source "drivers/mca/Kconfig"
2000 tristate "NatSemi SCx200 support"
2002 This provides basic support for National Semiconductor's
2003 (now AMD's) Geode processors. The driver probes for the
2004 PCI-IDs of several on-chip devices, so its a good dependency
2005 for other scx200_* drivers.
2007 If compiled as a module, the driver is named scx200.
2009 config SCx200HR_TIMER
2010 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2011 depends on SCx200 && GENERIC_TIME
2014 This driver provides a clocksource built upon the on-chip
2015 27MHz high-resolution timer. Its also a workaround for
2016 NSC Geode SC-1100's buggy TSC, which loses time when the
2017 processor goes idle (as is done by the scheduler). The
2018 other workaround is idle=poll boot option.
2020 config GEODE_MFGPT_TIMER
2022 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2023 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2025 This driver provides a clock event source based on the MFGPT
2026 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2027 MFGPTs have a better resolution and max interval than the
2028 generic PIT, and are suitable for use as high-res timers.
2031 bool "One Laptop Per Child support"
2034 Add support for detecting the unique features of the OLPC
2041 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2043 source "drivers/pcmcia/Kconfig"
2045 source "drivers/pci/hotplug/Kconfig"
2050 menu "Executable file formats / Emulations"
2052 source "fs/Kconfig.binfmt"
2054 config IA32_EMULATION
2055 bool "IA32 Emulation"
2057 select COMPAT_BINFMT_ELF
2059 Include code to run 32-bit programs under a 64-bit kernel. You should
2060 likely turn this on, unless you're 100% sure that you don't have any
2061 32-bit programs left.
2064 tristate "IA32 a.out support"
2065 depends on IA32_EMULATION
2067 Support old a.out binaries in the 32bit emulation.
2071 depends on IA32_EMULATION
2073 config COMPAT_FOR_U64_ALIGNMENT
2077 config SYSVIPC_COMPAT
2079 depends on COMPAT && SYSVIPC
2084 config HAVE_ATOMIC_IOMAP
2088 source "net/Kconfig"
2090 source "drivers/Kconfig"
2092 source "drivers/firmware/Kconfig"
2096 source "arch/x86/Kconfig.debug"
2098 source "security/Kconfig"
2100 source "crypto/Kconfig"
2102 source "arch/x86/kvm/Kconfig"
2104 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob