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_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
144 config ARCH_SUSPEND_POSSIBLE
151 config ARCH_POPULATES_NODE_MAP
158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
161 # Use the generic interrupt handling code in kernel/irq/:
162 config GENERIC_HARDIRQS
166 config GENERIC_IRQ_PROBE
170 config GENERIC_PENDING_IRQ
172 depends on GENERIC_HARDIRQS && SMP
175 config USE_GENERIC_SMP_HELPERS
181 depends on X86_32 && SMP
185 depends on X86_64 && SMP
192 config X86_TRAMPOLINE
194 depends on SMP || (64BIT && ACPI_SLEEP)
197 config X86_32_LAZY_GS
199 depends on X86_32 && !CC_STACKPROTECTOR
203 source "init/Kconfig"
204 source "kernel/Kconfig.freezer"
206 menu "Processor type and features"
208 source "kernel/time/Kconfig"
211 bool "Symmetric multi-processing support"
213 This enables support for systems with more than one CPU. If you have
214 a system with only one CPU, like most personal computers, say N. If
215 you have a system with more than one CPU, say Y.
217 If you say N here, the kernel will run on single and multiprocessor
218 machines, but will use only one CPU of a multiprocessor machine. If
219 you say Y here, the kernel will run on many, but not all,
220 singleprocessor machines. On a singleprocessor machine, the kernel
221 will run faster if you say N here.
223 Note that if you say Y here and choose architecture "586" or
224 "Pentium" under "Processor family", the kernel will not work on 486
225 architectures. Similarly, multiprocessor kernels for the "PPro"
226 architecture may not work on all Pentium based boards.
228 People using multiprocessor machines who say Y here should also say
229 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
230 Management" code will be disabled if you say Y here.
232 See also <file:Documentation/i386/IO-APIC.txt>,
233 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
234 <http://www.tldp.org/docs.html#howto>.
236 If you don't know what to do here, say N.
239 bool "Support x2apic"
240 depends on X86_LOCAL_APIC && X86_64
242 This enables x2apic support on CPUs that have this feature.
244 This allows 32-bit apic IDs (so it can support very large systems),
245 and accesses the local apic via MSRs not via mmio.
247 ( On certain CPU models you may need to enable INTR_REMAP too,
248 to get functional x2apic mode. )
250 If you don't know what to do here, say N.
253 bool "Support sparse irq numbering"
254 depends on PCI_MSI || HT_IRQ
256 This enables support for sparse irqs. This is useful for distro
257 kernels that want to define a high CONFIG_NR_CPUS value but still
258 want to have low kernel memory footprint on smaller machines.
260 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
261 out the irq_desc[] array in a more NUMA-friendly way. )
263 If you don't know what to do here, say N.
265 config NUMA_MIGRATE_IRQ_DESC
266 bool "Move irq desc when changing irq smp_affinity"
267 depends on SPARSE_IRQ && NUMA
270 This enables moving irq_desc to cpu/node that irq will use handled.
272 If you don't know what to do here, say N.
275 bool "Enable MPS table" if ACPI
277 depends on X86_LOCAL_APIC
279 For old smp systems that do not have proper acpi support. Newer systems
280 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
283 bool "Support for big SMP systems with more than 8 CPUs"
284 depends on X86_32 && SMP
286 This option is needed for the systems that have more than 8 CPUs
289 config X86_EXTENDED_PLATFORM
290 bool "Support for extended (non-PC) x86 platforms"
293 If you disable this option then the kernel will only support
294 standard PC platforms. (which covers the vast majority of
297 If you enable this option then you'll be able to select support
298 for the following (non-PC) 32 bit x86 platforms:
302 SGI 320/540 (Visual Workstation)
303 Summit/EXA (IBM x440)
304 Unisys ES7000 IA32 series
306 If you have one of these systems, or if you want to build a
307 generic distribution kernel, say Y here - otherwise say N.
311 config X86_EXTENDED_PLATFORM
312 bool "Support for extended (non-PC) x86 platforms"
315 If you disable this option then the kernel will only support
316 standard PC platforms. (which covers the vast majority of
319 If you enable this option then you'll be able to select support
320 for the following (non-PC) 64 bit x86 platforms:
324 If you have one of these systems, or if you want to build a
325 generic distribution kernel, say Y here - otherwise say N.
327 # This is an alphabetically sorted list of 64 bit extended platforms
328 # Please maintain the alphabetic order if and when there are additions
333 depends on X86_64 && PCI
334 depends on X86_EXTENDED_PLATFORM
336 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
337 supposed to run on these EM64T-based machines. Only choose this option
338 if you have one of these machines.
341 bool "SGI Ultraviolet"
343 depends on X86_EXTENDED_PLATFORM
346 This option is needed in order to support SGI Ultraviolet systems.
347 If you don't have one of these, you should say N here.
349 # Following is an alphabetically sorted list of 32 bit extended platforms
350 # Please maintain the alphabetic order if and when there are additions
355 depends on X86_EXTENDED_PLATFORM
357 Select this for an AMD Elan processor.
359 Do not use this option for K6/Athlon/Opteron processors!
361 If unsure, choose "PC-compatible" instead.
364 bool "RDC R-321x SoC"
366 depends on X86_EXTENDED_PLATFORM
368 select X86_REBOOTFIXUPS
370 This option is needed for RDC R-321x system-on-chip, also known
372 If you don't have one of these chips, you should say N here.
374 config X86_32_NON_STANDARD
375 bool "Support non-standard 32-bit SMP architectures"
376 depends on X86_32 && SMP
377 depends on X86_EXTENDED_PLATFORM
379 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
380 subarchitectures. It is intended for a generic binary kernel.
381 if you select them all, kernel will probe it one by one. and will
384 # Alphabetically sorted list of Non standard 32 bit platforms
387 bool "NUMAQ (IBM/Sequent)"
388 depends on X86_32_NON_STANDARD
392 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
393 NUMA multiquad box. This changes the way that processors are
394 bootstrapped, and uses Clustered Logical APIC addressing mode instead
395 of Flat Logical. You will need a new lynxer.elf file to flash your
396 firmware with - send email to <Martin.Bligh@us.ibm.com>.
399 bool "SGI 320/540 (Visual Workstation)"
400 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
401 depends on X86_32_NON_STANDARD
403 The SGI Visual Workstation series is an IA32-based workstation
404 based on SGI systems chips with some legacy PC hardware attached.
406 Say Y here to create a kernel to run on the SGI 320 or 540.
408 A kernel compiled for the Visual Workstation will run on general
409 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
412 bool "Summit/EXA (IBM x440)"
413 depends on X86_32_NON_STANDARD
415 This option is needed for IBM systems that use the Summit/EXA chipset.
416 In particular, it is needed for the x440.
419 bool "Unisys ES7000 IA32 series"
420 depends on X86_32_NON_STANDARD && X86_BIGSMP
422 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
423 supposed to run on an IA32-based Unisys ES7000 system.
425 config SCHED_OMIT_FRAME_POINTER
427 prompt "Single-depth WCHAN output"
430 Calculate simpler /proc/<PID>/wchan values. If this option
431 is disabled then wchan values will recurse back to the
432 caller function. This provides more accurate wchan values,
433 at the expense of slightly more scheduling overhead.
435 If in doubt, say "Y".
437 menuconfig PARAVIRT_GUEST
438 bool "Paravirtualized guest support"
440 Say Y here to get to see options related to running Linux under
441 various hypervisors. This option alone does not add any kernel code.
443 If you say N, all options in this submenu will be skipped and disabled.
447 source "arch/x86/xen/Kconfig"
450 bool "VMI Guest support"
454 VMI provides a paravirtualized interface to the VMware ESX server
455 (it could be used by other hypervisors in theory too, but is not
456 at the moment), by linking the kernel to a GPL-ed ROM module
457 provided by the hypervisor.
460 bool "KVM paravirtualized clock"
462 select PARAVIRT_CLOCK
464 Turning on this option will allow you to run a paravirtualized clock
465 when running over the KVM hypervisor. Instead of relying on a PIT
466 (or probably other) emulation by the underlying device model, the host
467 provides the guest with timing infrastructure such as time of day, and
471 bool "KVM Guest support"
474 This option enables various optimizations for running under the KVM
477 source "arch/x86/lguest/Kconfig"
480 bool "Enable paravirtualization code"
482 This changes the kernel so it can modify itself when it is run
483 under a hypervisor, potentially improving performance significantly
484 over full virtualization. However, when run without a hypervisor
485 the kernel is theoretically slower and slightly larger.
487 config PARAVIRT_CLOCK
493 config PARAVIRT_DEBUG
494 bool "paravirt-ops debugging"
495 depends on PARAVIRT && DEBUG_KERNEL
497 Enable to debug paravirt_ops internals. Specifically, BUG if
498 a paravirt_op is missing when it is called.
503 This option adds a kernel parameter 'memtest', which allows memtest
505 memtest=0, mean disabled; -- default
506 memtest=1, mean do 1 test pattern;
508 memtest=4, mean do 4 test patterns.
509 If you are unsure how to answer this question, answer N.
511 config X86_SUMMIT_NUMA
513 depends on X86_32 && NUMA && X86_32_NON_STANDARD
515 config X86_CYCLONE_TIMER
517 depends on X86_32_NON_STANDARD
519 source "arch/x86/Kconfig.cpu"
523 prompt "HPET Timer Support" if X86_32
525 Use the IA-PC HPET (High Precision Event Timer) to manage
526 time in preference to the PIT and RTC, if a HPET is
528 HPET is the next generation timer replacing legacy 8254s.
529 The HPET provides a stable time base on SMP
530 systems, unlike the TSC, but it is more expensive to access,
531 as it is off-chip. You can find the HPET spec at
532 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
534 You can safely choose Y here. However, HPET will only be
535 activated if the platform and the BIOS support this feature.
536 Otherwise the 8254 will be used for timing services.
538 Choose N to continue using the legacy 8254 timer.
540 config HPET_EMULATE_RTC
542 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
544 # Mark as embedded because too many people got it wrong.
545 # The code disables itself when not needed.
548 bool "Enable DMI scanning" if EMBEDDED
550 Enabled scanning of DMI to identify machine quirks. Say Y
551 here unless you have verified that your setup is not
552 affected by entries in the DMI blacklist. Required by PNP
556 bool "GART IOMMU support" if EMBEDDED
560 depends on X86_64 && PCI
562 Support for full DMA access of devices with 32bit memory access only
563 on systems with more than 3GB. This is usually needed for USB,
564 sound, many IDE/SATA chipsets and some other devices.
565 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
566 based hardware IOMMU and a software bounce buffer based IOMMU used
567 on Intel systems and as fallback.
568 The code is only active when needed (enough memory and limited
569 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
573 bool "IBM Calgary IOMMU support"
575 depends on X86_64 && PCI && EXPERIMENTAL
577 Support for hardware IOMMUs in IBM's xSeries x366 and x460
578 systems. Needed to run systems with more than 3GB of memory
579 properly with 32-bit PCI devices that do not support DAC
580 (Double Address Cycle). Calgary also supports bus level
581 isolation, where all DMAs pass through the IOMMU. This
582 prevents them from going anywhere except their intended
583 destination. This catches hard-to-find kernel bugs and
584 mis-behaving drivers and devices that do not use the DMA-API
585 properly to set up their DMA buffers. The IOMMU can be
586 turned off at boot time with the iommu=off parameter.
587 Normally the kernel will make the right choice by itself.
590 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
592 prompt "Should Calgary be enabled by default?"
593 depends on CALGARY_IOMMU
595 Should Calgary be enabled by default? if you choose 'y', Calgary
596 will be used (if it exists). If you choose 'n', Calgary will not be
597 used even if it exists. If you choose 'n' and would like to use
598 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
602 bool "AMD IOMMU support"
605 depends on X86_64 && PCI && ACPI
607 With this option you can enable support for AMD IOMMU hardware in
608 your system. An IOMMU is a hardware component which provides
609 remapping of DMA memory accesses from devices. With an AMD IOMMU you
610 can isolate the the DMA memory of different devices and protect the
611 system from misbehaving device drivers or hardware.
613 You can find out if your system has an AMD IOMMU if you look into
614 your BIOS for an option to enable it or if you have an IVRS ACPI
617 config AMD_IOMMU_STATS
618 bool "Export AMD IOMMU statistics to debugfs"
622 This option enables code in the AMD IOMMU driver to collect various
623 statistics about whats happening in the driver and exports that
624 information to userspace via debugfs.
627 # need this always selected by IOMMU for the VIA workaround
631 Support for software bounce buffers used on x86-64 systems
632 which don't have a hardware IOMMU (e.g. the current generation
633 of Intel's x86-64 CPUs). Using this PCI devices which can only
634 access 32-bits of memory can be used on systems with more than
635 3 GB of memory. If unsure, say Y.
638 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
641 def_bool (AMD_IOMMU || DMAR)
644 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
645 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
646 select CPUMASK_OFFSTACK
649 Configure maximum number of CPUS and NUMA Nodes for this architecture.
653 int "Maximum number of CPUs" if SMP && !MAXSMP
654 range 2 512 if SMP && !MAXSMP
656 default "4096" if MAXSMP
657 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
660 This allows you to specify the maximum number of CPUs which this
661 kernel will support. The maximum supported value is 512 and the
662 minimum value which makes sense is 2.
664 This is purely to save memory - each supported CPU adds
665 approximately eight kilobytes to the kernel image.
668 bool "SMT (Hyperthreading) scheduler support"
671 SMT scheduler support improves the CPU scheduler's decision making
672 when dealing with Intel Pentium 4 chips with HyperThreading at a
673 cost of slightly increased overhead in some places. If unsure say
678 prompt "Multi-core scheduler support"
681 Multi-core scheduler support improves the CPU scheduler's decision
682 making when dealing with multi-core CPU chips at a cost of slightly
683 increased overhead in some places. If unsure say N here.
685 source "kernel/Kconfig.preempt"
688 bool "Local APIC support on uniprocessors"
689 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
691 A local APIC (Advanced Programmable Interrupt Controller) is an
692 integrated interrupt controller in the CPU. If you have a single-CPU
693 system which has a processor with a local APIC, you can say Y here to
694 enable and use it. If you say Y here even though your machine doesn't
695 have a local APIC, then the kernel will still run with no slowdown at
696 all. The local APIC supports CPU-generated self-interrupts (timer,
697 performance counters), and the NMI watchdog which detects hard
701 bool "IO-APIC support on uniprocessors"
702 depends on X86_UP_APIC
704 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
705 SMP-capable replacement for PC-style interrupt controllers. Most
706 SMP systems and many recent uniprocessor systems have one.
708 If you have a single-CPU system with an IO-APIC, you can say Y here
709 to use it. If you say Y here even though your machine doesn't have
710 an IO-APIC, then the kernel will still run with no slowdown at all.
712 config X86_LOCAL_APIC
714 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
718 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
720 config X86_VISWS_APIC
722 depends on X86_32 && X86_VISWS
724 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
725 bool "Reroute for broken boot IRQs"
727 depends on X86_IO_APIC
729 This option enables a workaround that fixes a source of
730 spurious interrupts. This is recommended when threaded
731 interrupt handling is used on systems where the generation of
732 superfluous "boot interrupts" cannot be disabled.
734 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
735 entry in the chipset's IO-APIC is masked (as, e.g. the RT
736 kernel does during interrupt handling). On chipsets where this
737 boot IRQ generation cannot be disabled, this workaround keeps
738 the original IRQ line masked so that only the equivalent "boot
739 IRQ" is delivered to the CPUs. The workaround also tells the
740 kernel to set up the IRQ handler on the boot IRQ line. In this
741 way only one interrupt is delivered to the kernel. Otherwise
742 the spurious second interrupt may cause the kernel to bring
743 down (vital) interrupt lines.
745 Only affects "broken" chipsets. Interrupt sharing may be
746 increased on these systems.
749 bool "Machine Check Exception"
751 Machine Check Exception support allows the processor to notify the
752 kernel if it detects a problem (e.g. overheating, component failure).
753 The action the kernel takes depends on the severity of the problem,
754 ranging from a warning message on the console, to halting the machine.
755 Your processor must be a Pentium or newer to support this - check the
756 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
757 have a design flaw which leads to false MCE events - hence MCE is
758 disabled on all P5 processors, unless explicitly enabled with "mce"
759 as a boot argument. Similarly, if MCE is built in and creates a
760 problem on some new non-standard machine, you can boot with "nomce"
761 to disable it. MCE support simply ignores non-MCE processors like
762 the 386 and 486, so nearly everyone can say Y here.
766 prompt "Intel MCE features"
767 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
769 Additional support for intel specific MCE features such as
774 prompt "AMD MCE features"
775 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
777 Additional support for AMD specific MCE features such as
778 the DRAM Error Threshold.
780 config X86_MCE_NONFATAL
781 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
782 depends on X86_32 && X86_MCE
784 Enabling this feature starts a timer that triggers every 5 seconds which
785 will look at the machine check registers to see if anything happened.
786 Non-fatal problems automatically get corrected (but still logged).
787 Disable this if you don't want to see these messages.
788 Seeing the messages this option prints out may be indicative of dying
789 or out-of-spec (ie, overclocked) hardware.
790 This option only does something on certain CPUs.
791 (AMD Athlon/Duron and Intel Pentium 4)
793 config X86_MCE_P4THERMAL
794 bool "check for P4 thermal throttling interrupt."
795 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
797 Enabling this feature will cause a message to be printed when the P4
798 enters thermal throttling.
801 bool "Enable VM86 support" if EMBEDDED
805 This option is required by programs like DOSEMU to run 16-bit legacy
806 code on X86 processors. It also may be needed by software like
807 XFree86 to initialize some video cards via BIOS. Disabling this
808 option saves about 6k.
811 tristate "Toshiba Laptop support"
814 This adds a driver to safely access the System Management Mode of
815 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
816 not work on models with a Phoenix BIOS. The System Management Mode
817 is used to set the BIOS and power saving options on Toshiba portables.
819 For information on utilities to make use of this driver see the
820 Toshiba Linux utilities web site at:
821 <http://www.buzzard.org.uk/toshiba/>.
823 Say Y if you intend to run this kernel on a Toshiba portable.
827 tristate "Dell laptop support"
829 This adds a driver to safely access the System Management Mode
830 of the CPU on the Dell Inspiron 8000. The System Management Mode
831 is used to read cpu temperature and cooling fan status and to
832 control the fans on the I8K portables.
834 This driver has been tested only on the Inspiron 8000 but it may
835 also work with other Dell laptops. You can force loading on other
836 models by passing the parameter `force=1' to the module. Use at
839 For information on utilities to make use of this driver see the
840 I8K Linux utilities web site at:
841 <http://people.debian.org/~dz/i8k/>
843 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
846 config X86_REBOOTFIXUPS
847 bool "Enable X86 board specific fixups for reboot"
850 This enables chipset and/or board specific fixups to be done
851 in order to get reboot to work correctly. This is only needed on
852 some combinations of hardware and BIOS. The symptom, for which
853 this config is intended, is when reboot ends with a stalled/hung
856 Currently, the only fixup is for the Geode machines using
857 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
859 Say Y if you want to enable the fixup. Currently, it's safe to
860 enable this option even if you don't need it.
864 tristate "/dev/cpu/microcode - microcode support"
867 If you say Y here, you will be able to update the microcode on
868 certain Intel and AMD processors. The Intel support is for the
869 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
870 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
871 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
872 You will obviously need the actual microcode binary data itself
873 which is not shipped with the Linux kernel.
875 This option selects the general module only, you need to select
876 at least one vendor specific module as well.
878 To compile this driver as a module, choose M here: the
879 module will be called microcode.
881 config MICROCODE_INTEL
882 bool "Intel microcode patch loading support"
887 This options enables microcode patch loading support for Intel
890 For latest news and information on obtaining all the required
891 Intel ingredients for this driver, check:
892 <http://www.urbanmyth.org/microcode/>.
895 bool "AMD microcode patch loading support"
899 If you select this option, microcode patch loading support for AMD
900 processors will be enabled.
902 config MICROCODE_OLD_INTERFACE
907 tristate "/dev/cpu/*/msr - Model-specific register support"
909 This device gives privileged processes access to the x86
910 Model-Specific Registers (MSRs). It is a character device with
911 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
912 MSR accesses are directed to a specific CPU on multi-processor
916 tristate "/dev/cpu/*/cpuid - CPU information support"
918 This device gives processes access to the x86 CPUID instruction to
919 be executed on a specific processor. It is a character device
920 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
924 prompt "High Memory Support"
925 default HIGHMEM4G if !X86_NUMAQ
926 default HIGHMEM64G if X86_NUMAQ
931 depends on !X86_NUMAQ
933 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
934 However, the address space of 32-bit x86 processors is only 4
935 Gigabytes large. That means that, if you have a large amount of
936 physical memory, not all of it can be "permanently mapped" by the
937 kernel. The physical memory that's not permanently mapped is called
940 If you are compiling a kernel which will never run on a machine with
941 more than 1 Gigabyte total physical RAM, answer "off" here (default
942 choice and suitable for most users). This will result in a "3GB/1GB"
943 split: 3GB are mapped so that each process sees a 3GB virtual memory
944 space and the remaining part of the 4GB virtual memory space is used
945 by the kernel to permanently map as much physical memory as
948 If the machine has between 1 and 4 Gigabytes physical RAM, then
951 If more than 4 Gigabytes is used then answer "64GB" here. This
952 selection turns Intel PAE (Physical Address Extension) mode on.
953 PAE implements 3-level paging on IA32 processors. PAE is fully
954 supported by Linux, PAE mode is implemented on all recent Intel
955 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
956 then the kernel will not boot on CPUs that don't support PAE!
958 The actual amount of total physical memory will either be
959 auto detected or can be forced by using a kernel command line option
960 such as "mem=256M". (Try "man bootparam" or see the documentation of
961 your boot loader (lilo or loadlin) about how to pass options to the
962 kernel at boot time.)
964 If unsure, say "off".
968 depends on !X86_NUMAQ
970 Select this if you have a 32-bit processor and between 1 and 4
971 gigabytes of physical RAM.
975 depends on !M386 && !M486
978 Select this if you have a 32-bit processor and more than 4
979 gigabytes of physical RAM.
984 depends on EXPERIMENTAL
985 prompt "Memory split" if EMBEDDED
989 Select the desired split between kernel and user memory.
991 If the address range available to the kernel is less than the
992 physical memory installed, the remaining memory will be available
993 as "high memory". Accessing high memory is a little more costly
994 than low memory, as it needs to be mapped into the kernel first.
995 Note that increasing the kernel address space limits the range
996 available to user programs, making the address space there
997 tighter. Selecting anything other than the default 3G/1G split
998 will also likely make your kernel incompatible with binary-only
1001 If you are not absolutely sure what you are doing, leave this
1005 bool "3G/1G user/kernel split"
1006 config VMSPLIT_3G_OPT
1008 bool "3G/1G user/kernel split (for full 1G low memory)"
1010 bool "2G/2G user/kernel split"
1011 config VMSPLIT_2G_OPT
1013 bool "2G/2G user/kernel split (for full 2G low memory)"
1015 bool "1G/3G user/kernel split"
1020 default 0xB0000000 if VMSPLIT_3G_OPT
1021 default 0x80000000 if VMSPLIT_2G
1022 default 0x78000000 if VMSPLIT_2G_OPT
1023 default 0x40000000 if VMSPLIT_1G
1029 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1032 bool "PAE (Physical Address Extension) Support"
1033 depends on X86_32 && !HIGHMEM4G
1035 PAE is required for NX support, and furthermore enables
1036 larger swapspace support for non-overcommit purposes. It
1037 has the cost of more pagetable lookup overhead, and also
1038 consumes more pagetable space per process.
1040 config ARCH_PHYS_ADDR_T_64BIT
1041 def_bool X86_64 || X86_PAE
1043 config DIRECT_GBPAGES
1044 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1048 Allow the kernel linear mapping to use 1GB pages on CPUs that
1049 support it. This can improve the kernel's performance a tiny bit by
1050 reducing TLB pressure. If in doubt, say "Y".
1052 # Common NUMA Features
1054 bool "Numa Memory Allocation and Scheduler Support"
1056 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1057 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1059 Enable NUMA (Non Uniform Memory Access) support.
1061 The kernel will try to allocate memory used by a CPU on the
1062 local memory controller of the CPU and add some more
1063 NUMA awareness to the kernel.
1065 For 64-bit this is recommended if the system is Intel Core i7
1066 (or later), AMD Opteron, or EM64T NUMA.
1068 For 32-bit this is only needed on (rare) 32-bit-only platforms
1069 that support NUMA topologies, such as NUMAQ / Summit, or if you
1070 boot a 32-bit kernel on a 64-bit NUMA platform.
1072 Otherwise, you should say N.
1074 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1075 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1079 prompt "Old style AMD Opteron NUMA detection"
1080 depends on X86_64 && NUMA && PCI
1082 Enable K8 NUMA node topology detection. You should say Y here if
1083 you have a multi processor AMD K8 system. This uses an old
1084 method to read the NUMA configuration directly from the builtin
1085 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1086 instead, which also takes priority if both are compiled in.
1088 config X86_64_ACPI_NUMA
1090 prompt "ACPI NUMA detection"
1091 depends on X86_64 && NUMA && ACPI && PCI
1094 Enable ACPI SRAT based node topology detection.
1096 # Some NUMA nodes have memory ranges that span
1097 # other nodes. Even though a pfn is valid and
1098 # between a node's start and end pfns, it may not
1099 # reside on that node. See memmap_init_zone()
1101 config NODES_SPAN_OTHER_NODES
1103 depends on X86_64_ACPI_NUMA
1106 bool "NUMA emulation"
1107 depends on X86_64 && NUMA
1109 Enable NUMA emulation. A flat machine will be split
1110 into virtual nodes when booted with "numa=fake=N", where N is the
1111 number of nodes. This is only useful for debugging.
1114 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1116 default "9" if MAXSMP
1117 default "6" if X86_64
1118 default "4" if X86_NUMAQ
1120 depends on NEED_MULTIPLE_NODES
1122 Specify the maximum number of NUMA Nodes available on the target
1123 system. Increases memory reserved to accomodate various tables.
1125 config HAVE_ARCH_BOOTMEM_NODE
1127 depends on X86_32 && NUMA
1129 config ARCH_HAVE_MEMORY_PRESENT
1131 depends on X86_32 && DISCONTIGMEM
1133 config NEED_NODE_MEMMAP_SIZE
1135 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1137 config HAVE_ARCH_ALLOC_REMAP
1139 depends on X86_32 && NUMA
1141 config ARCH_FLATMEM_ENABLE
1143 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1145 config ARCH_DISCONTIGMEM_ENABLE
1147 depends on NUMA && X86_32
1149 config ARCH_DISCONTIGMEM_DEFAULT
1151 depends on NUMA && X86_32
1153 config ARCH_SPARSEMEM_DEFAULT
1157 config ARCH_SPARSEMEM_ENABLE
1159 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1160 select SPARSEMEM_STATIC if X86_32
1161 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1163 config ARCH_SELECT_MEMORY_MODEL
1165 depends on ARCH_SPARSEMEM_ENABLE
1167 config ARCH_MEMORY_PROBE
1169 depends on MEMORY_HOTPLUG
1174 bool "Allocate 3rd-level pagetables from highmem"
1175 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1177 The VM uses one page table entry for each page of physical memory.
1178 For systems with a lot of RAM, this can be wasteful of precious
1179 low memory. Setting this option will put user-space page table
1180 entries in high memory.
1182 config X86_CHECK_BIOS_CORRUPTION
1183 bool "Check for low memory corruption"
1185 Periodically check for memory corruption in low memory, which
1186 is suspected to be caused by BIOS. Even when enabled in the
1187 configuration, it is disabled at runtime. Enable it by
1188 setting "memory_corruption_check=1" on the kernel command
1189 line. By default it scans the low 64k of memory every 60
1190 seconds; see the memory_corruption_check_size and
1191 memory_corruption_check_period parameters in
1192 Documentation/kernel-parameters.txt to adjust this.
1194 When enabled with the default parameters, this option has
1195 almost no overhead, as it reserves a relatively small amount
1196 of memory and scans it infrequently. It both detects corruption
1197 and prevents it from affecting the running system.
1199 It is, however, intended as a diagnostic tool; if repeatable
1200 BIOS-originated corruption always affects the same memory,
1201 you can use memmap= to prevent the kernel from using that
1204 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1205 bool "Set the default setting of memory_corruption_check"
1206 depends on X86_CHECK_BIOS_CORRUPTION
1209 Set whether the default state of memory_corruption_check is
1212 config X86_RESERVE_LOW_64K
1213 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1216 Reserve the first 64K of physical RAM on BIOSes that are known
1217 to potentially corrupt that memory range. A numbers of BIOSes are
1218 known to utilize this area during suspend/resume, so it must not
1219 be used by the kernel.
1221 Set this to N if you are absolutely sure that you trust the BIOS
1222 to get all its memory reservations and usages right.
1224 If you have doubts about the BIOS (e.g. suspend/resume does not
1225 work or there's kernel crashes after certain hardware hotplug
1226 events) and it's not AMI or Phoenix, then you might want to enable
1227 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1228 corruption patterns.
1232 config MATH_EMULATION
1234 prompt "Math emulation" if X86_32
1236 Linux can emulate a math coprocessor (used for floating point
1237 operations) if you don't have one. 486DX and Pentium processors have
1238 a math coprocessor built in, 486SX and 386 do not, unless you added
1239 a 487DX or 387, respectively. (The messages during boot time can
1240 give you some hints here ["man dmesg"].) Everyone needs either a
1241 coprocessor or this emulation.
1243 If you don't have a math coprocessor, you need to say Y here; if you
1244 say Y here even though you have a coprocessor, the coprocessor will
1245 be used nevertheless. (This behavior can be changed with the kernel
1246 command line option "no387", which comes handy if your coprocessor
1247 is broken. Try "man bootparam" or see the documentation of your boot
1248 loader (lilo or loadlin) about how to pass options to the kernel at
1249 boot time.) This means that it is a good idea to say Y here if you
1250 intend to use this kernel on different machines.
1252 More information about the internals of the Linux math coprocessor
1253 emulation can be found in <file:arch/x86/math-emu/README>.
1255 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1256 kernel, it won't hurt.
1259 bool "MTRR (Memory Type Range Register) support"
1261 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1262 the Memory Type Range Registers (MTRRs) may be used to control
1263 processor access to memory ranges. This is most useful if you have
1264 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1265 allows bus write transfers to be combined into a larger transfer
1266 before bursting over the PCI/AGP bus. This can increase performance
1267 of image write operations 2.5 times or more. Saying Y here creates a
1268 /proc/mtrr file which may be used to manipulate your processor's
1269 MTRRs. Typically the X server should use this.
1271 This code has a reasonably generic interface so that similar
1272 control registers on other processors can be easily supported
1275 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1276 Registers (ARRs) which provide a similar functionality to MTRRs. For
1277 these, the ARRs are used to emulate the MTRRs.
1278 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1279 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1280 write-combining. All of these processors are supported by this code
1281 and it makes sense to say Y here if you have one of them.
1283 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1284 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1285 can lead to all sorts of problems, so it's good to say Y here.
1287 You can safely say Y even if your machine doesn't have MTRRs, you'll
1288 just add about 9 KB to your kernel.
1290 See <file:Documentation/x86/mtrr.txt> for more information.
1292 config MTRR_SANITIZER
1294 prompt "MTRR cleanup support"
1297 Convert MTRR layout from continuous to discrete, so X drivers can
1298 add writeback entries.
1300 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1301 The largest mtrr entry size for a continous block can be set with
1306 config MTRR_SANITIZER_ENABLE_DEFAULT
1307 int "MTRR cleanup enable value (0-1)"
1310 depends on MTRR_SANITIZER
1312 Enable mtrr cleanup default value
1314 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1315 int "MTRR cleanup spare reg num (0-7)"
1318 depends on MTRR_SANITIZER
1320 mtrr cleanup spare entries default, it can be changed via
1321 mtrr_spare_reg_nr=N on the kernel command line.
1325 prompt "x86 PAT support"
1328 Use PAT attributes to setup page level cache control.
1330 PATs are the modern equivalents of MTRRs and are much more
1331 flexible than MTRRs.
1333 Say N here if you see bootup problems (boot crash, boot hang,
1334 spontaneous reboots) or a non-working video driver.
1339 bool "EFI runtime service support"
1342 This enables the kernel to use EFI runtime services that are
1343 available (such as the EFI variable services).
1345 This option is only useful on systems that have EFI firmware.
1346 In addition, you should use the latest ELILO loader available
1347 at <http://elilo.sourceforge.net> in order to take advantage
1348 of EFI runtime services. However, even with this option, the
1349 resultant kernel should continue to boot on existing non-EFI
1354 prompt "Enable seccomp to safely compute untrusted bytecode"
1356 This kernel feature is useful for number crunching applications
1357 that may need to compute untrusted bytecode during their
1358 execution. By using pipes or other transports made available to
1359 the process as file descriptors supporting the read/write
1360 syscalls, it's possible to isolate those applications in
1361 their own address space using seccomp. Once seccomp is
1362 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1363 and the task is only allowed to execute a few safe syscalls
1364 defined by each seccomp mode.
1366 If unsure, say Y. Only embedded should say N here.
1368 config CC_STACKPROTECTOR_ALL
1371 config CC_STACKPROTECTOR
1372 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1373 select CC_STACKPROTECTOR_ALL
1375 This option turns on the -fstack-protector GCC feature. This
1376 feature puts, at the beginning of functions, a canary value on
1377 the stack just before the return address, and validates
1378 the value just before actually returning. Stack based buffer
1379 overflows (that need to overwrite this return address) now also
1380 overwrite the canary, which gets detected and the attack is then
1381 neutralized via a kernel panic.
1383 This feature requires gcc version 4.2 or above, or a distribution
1384 gcc with the feature backported. Older versions are automatically
1385 detected and for those versions, this configuration option is
1386 ignored. (and a warning is printed during bootup)
1388 source kernel/Kconfig.hz
1391 bool "kexec system call"
1393 kexec is a system call that implements the ability to shutdown your
1394 current kernel, and to start another kernel. It is like a reboot
1395 but it is independent of the system firmware. And like a reboot
1396 you can start any kernel with it, not just Linux.
1398 The name comes from the similarity to the exec system call.
1400 It is an ongoing process to be certain the hardware in a machine
1401 is properly shutdown, so do not be surprised if this code does not
1402 initially work for you. It may help to enable device hotplugging
1403 support. As of this writing the exact hardware interface is
1404 strongly in flux, so no good recommendation can be made.
1407 bool "kernel crash dumps"
1408 depends on X86_64 || (X86_32 && HIGHMEM)
1410 Generate crash dump after being started by kexec.
1411 This should be normally only set in special crash dump kernels
1412 which are loaded in the main kernel with kexec-tools into
1413 a specially reserved region and then later executed after
1414 a crash by kdump/kexec. The crash dump kernel must be compiled
1415 to a memory address not used by the main kernel or BIOS using
1416 PHYSICAL_START, or it must be built as a relocatable image
1417 (CONFIG_RELOCATABLE=y).
1418 For more details see Documentation/kdump/kdump.txt
1421 bool "kexec jump (EXPERIMENTAL)"
1422 depends on EXPERIMENTAL
1423 depends on KEXEC && HIBERNATION && X86_32
1425 Jump between original kernel and kexeced kernel and invoke
1426 code in physical address mode via KEXEC
1428 config PHYSICAL_START
1429 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1430 default "0x1000000" if X86_NUMAQ
1431 default "0x200000" if X86_64
1434 This gives the physical address where the kernel is loaded.
1436 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1437 bzImage will decompress itself to above physical address and
1438 run from there. Otherwise, bzImage will run from the address where
1439 it has been loaded by the boot loader and will ignore above physical
1442 In normal kdump cases one does not have to set/change this option
1443 as now bzImage can be compiled as a completely relocatable image
1444 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1445 address. This option is mainly useful for the folks who don't want
1446 to use a bzImage for capturing the crash dump and want to use a
1447 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1448 to be specifically compiled to run from a specific memory area
1449 (normally a reserved region) and this option comes handy.
1451 So if you are using bzImage for capturing the crash dump, leave
1452 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1453 Otherwise if you plan to use vmlinux for capturing the crash dump
1454 change this value to start of the reserved region (Typically 16MB
1455 0x1000000). In other words, it can be set based on the "X" value as
1456 specified in the "crashkernel=YM@XM" command line boot parameter
1457 passed to the panic-ed kernel. Typically this parameter is set as
1458 crashkernel=64M@16M. Please take a look at
1459 Documentation/kdump/kdump.txt for more details about crash dumps.
1461 Usage of bzImage for capturing the crash dump is recommended as
1462 one does not have to build two kernels. Same kernel can be used
1463 as production kernel and capture kernel. Above option should have
1464 gone away after relocatable bzImage support is introduced. But it
1465 is present because there are users out there who continue to use
1466 vmlinux for dump capture. This option should go away down the
1469 Don't change this unless you know what you are doing.
1472 bool "Build a relocatable kernel (EXPERIMENTAL)"
1473 depends on EXPERIMENTAL
1475 This builds a kernel image that retains relocation information
1476 so it can be loaded someplace besides the default 1MB.
1477 The relocations tend to make the kernel binary about 10% larger,
1478 but are discarded at runtime.
1480 One use is for the kexec on panic case where the recovery kernel
1481 must live at a different physical address than the primary
1484 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1485 it has been loaded at and the compile time physical address
1486 (CONFIG_PHYSICAL_START) is ignored.
1488 config PHYSICAL_ALIGN
1490 prompt "Alignment value to which kernel should be aligned" if X86_32
1491 default "0x100000" if X86_32
1492 default "0x200000" if X86_64
1493 range 0x2000 0x400000
1495 This value puts the alignment restrictions on physical address
1496 where kernel is loaded and run from. Kernel is compiled for an
1497 address which meets above alignment restriction.
1499 If bootloader loads the kernel at a non-aligned address and
1500 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1501 address aligned to above value and run from there.
1503 If bootloader loads the kernel at a non-aligned address and
1504 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1505 load address and decompress itself to the address it has been
1506 compiled for and run from there. The address for which kernel is
1507 compiled already meets above alignment restrictions. Hence the
1508 end result is that kernel runs from a physical address meeting
1509 above alignment restrictions.
1511 Don't change this unless you know what you are doing.
1514 bool "Support for hot-pluggable CPUs"
1515 depends on SMP && HOTPLUG
1517 Say Y here to allow turning CPUs off and on. CPUs can be
1518 controlled through /sys/devices/system/cpu.
1519 ( Note: power management support will enable this option
1520 automatically on SMP systems. )
1521 Say N if you want to disable CPU hotplug.
1525 prompt "Compat VDSO support"
1526 depends on X86_32 || IA32_EMULATION
1528 Map the 32-bit VDSO to the predictable old-style address too.
1530 Say N here if you are running a sufficiently recent glibc
1531 version (2.3.3 or later), to remove the high-mapped
1532 VDSO mapping and to exclusively use the randomized VDSO.
1537 bool "Built-in kernel command line"
1540 Allow for specifying boot arguments to the kernel at
1541 build time. On some systems (e.g. embedded ones), it is
1542 necessary or convenient to provide some or all of the
1543 kernel boot arguments with the kernel itself (that is,
1544 to not rely on the boot loader to provide them.)
1546 To compile command line arguments into the kernel,
1547 set this option to 'Y', then fill in the
1548 the boot arguments in CONFIG_CMDLINE.
1550 Systems with fully functional boot loaders (i.e. non-embedded)
1551 should leave this option set to 'N'.
1554 string "Built-in kernel command string"
1555 depends on CMDLINE_BOOL
1558 Enter arguments here that should be compiled into the kernel
1559 image and used at boot time. If the boot loader provides a
1560 command line at boot time, it is appended to this string to
1561 form the full kernel command line, when the system boots.
1563 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1564 change this behavior.
1566 In most cases, the command line (whether built-in or provided
1567 by the boot loader) should specify the device for the root
1570 config CMDLINE_OVERRIDE
1571 bool "Built-in command line overrides boot loader arguments"
1573 depends on CMDLINE_BOOL
1575 Set this option to 'Y' to have the kernel ignore the boot loader
1576 command line, and use ONLY the built-in command line.
1578 This is used to work around broken boot loaders. This should
1579 be set to 'N' under normal conditions.
1583 config ARCH_ENABLE_MEMORY_HOTPLUG
1585 depends on X86_64 || (X86_32 && HIGHMEM)
1587 config ARCH_ENABLE_MEMORY_HOTREMOVE
1589 depends on MEMORY_HOTPLUG
1591 config HAVE_ARCH_EARLY_PFN_TO_NID
1595 menu "Power management and ACPI options"
1597 config ARCH_HIBERNATION_HEADER
1599 depends on X86_64 && HIBERNATION
1601 source "kernel/power/Kconfig"
1603 source "drivers/acpi/Kconfig"
1608 depends on APM || APM_MODULE
1611 tristate "APM (Advanced Power Management) BIOS support"
1612 depends on X86_32 && PM_SLEEP
1614 APM is a BIOS specification for saving power using several different
1615 techniques. This is mostly useful for battery powered laptops with
1616 APM compliant BIOSes. If you say Y here, the system time will be
1617 reset after a RESUME operation, the /proc/apm device will provide
1618 battery status information, and user-space programs will receive
1619 notification of APM "events" (e.g. battery status change).
1621 If you select "Y" here, you can disable actual use of the APM
1622 BIOS by passing the "apm=off" option to the kernel at boot time.
1624 Note that the APM support is almost completely disabled for
1625 machines with more than one CPU.
1627 In order to use APM, you will need supporting software. For location
1628 and more information, read <file:Documentation/power/pm.txt> and the
1629 Battery Powered Linux mini-HOWTO, available from
1630 <http://www.tldp.org/docs.html#howto>.
1632 This driver does not spin down disk drives (see the hdparm(8)
1633 manpage ("man 8 hdparm") for that), and it doesn't turn off
1634 VESA-compliant "green" monitors.
1636 This driver does not support the TI 4000M TravelMate and the ACER
1637 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1638 desktop machines also don't have compliant BIOSes, and this driver
1639 may cause those machines to panic during the boot phase.
1641 Generally, if you don't have a battery in your machine, there isn't
1642 much point in using this driver and you should say N. If you get
1643 random kernel OOPSes or reboots that don't seem to be related to
1644 anything, try disabling/enabling this option (or disabling/enabling
1647 Some other things you should try when experiencing seemingly random,
1650 1) make sure that you have enough swap space and that it is
1652 2) pass the "no-hlt" option to the kernel
1653 3) switch on floating point emulation in the kernel and pass
1654 the "no387" option to the kernel
1655 4) pass the "floppy=nodma" option to the kernel
1656 5) pass the "mem=4M" option to the kernel (thereby disabling
1657 all but the first 4 MB of RAM)
1658 6) make sure that the CPU is not over clocked.
1659 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1660 8) disable the cache from your BIOS settings
1661 9) install a fan for the video card or exchange video RAM
1662 10) install a better fan for the CPU
1663 11) exchange RAM chips
1664 12) exchange the motherboard.
1666 To compile this driver as a module, choose M here: the
1667 module will be called apm.
1671 config APM_IGNORE_USER_SUSPEND
1672 bool "Ignore USER SUSPEND"
1674 This option will ignore USER SUSPEND requests. On machines with a
1675 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1676 series notebooks, it is necessary to say Y because of a BIOS bug.
1678 config APM_DO_ENABLE
1679 bool "Enable PM at boot time"
1681 Enable APM features at boot time. From page 36 of the APM BIOS
1682 specification: "When disabled, the APM BIOS does not automatically
1683 power manage devices, enter the Standby State, enter the Suspend
1684 State, or take power saving steps in response to CPU Idle calls."
1685 This driver will make CPU Idle calls when Linux is idle (unless this
1686 feature is turned off -- see "Do CPU IDLE calls", below). This
1687 should always save battery power, but more complicated APM features
1688 will be dependent on your BIOS implementation. You may need to turn
1689 this option off if your computer hangs at boot time when using APM
1690 support, or if it beeps continuously instead of suspending. Turn
1691 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1692 T400CDT. This is off by default since most machines do fine without
1696 bool "Make CPU Idle calls when idle"
1698 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1699 On some machines, this can activate improved power savings, such as
1700 a slowed CPU clock rate, when the machine is idle. These idle calls
1701 are made after the idle loop has run for some length of time (e.g.,
1702 333 mS). On some machines, this will cause a hang at boot time or
1703 whenever the CPU becomes idle. (On machines with more than one CPU,
1704 this option does nothing.)
1706 config APM_DISPLAY_BLANK
1707 bool "Enable console blanking using APM"
1709 Enable console blanking using the APM. Some laptops can use this to
1710 turn off the LCD backlight when the screen blanker of the Linux
1711 virtual console blanks the screen. Note that this is only used by
1712 the virtual console screen blanker, and won't turn off the backlight
1713 when using the X Window system. This also doesn't have anything to
1714 do with your VESA-compliant power-saving monitor. Further, this
1715 option doesn't work for all laptops -- it might not turn off your
1716 backlight at all, or it might print a lot of errors to the console,
1717 especially if you are using gpm.
1719 config APM_ALLOW_INTS
1720 bool "Allow interrupts during APM BIOS calls"
1722 Normally we disable external interrupts while we are making calls to
1723 the APM BIOS as a measure to lessen the effects of a badly behaving
1724 BIOS implementation. The BIOS should reenable interrupts if it
1725 needs to. Unfortunately, some BIOSes do not -- especially those in
1726 many of the newer IBM Thinkpads. If you experience hangs when you
1727 suspend, try setting this to Y. Otherwise, say N.
1731 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1733 source "drivers/cpuidle/Kconfig"
1735 source "drivers/idle/Kconfig"
1740 menu "Bus options (PCI etc.)"
1745 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1747 Find out whether you have a PCI motherboard. PCI is the name of a
1748 bus system, i.e. the way the CPU talks to the other stuff inside
1749 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1750 VESA. If you have PCI, say Y, otherwise N.
1753 prompt "PCI access mode"
1754 depends on X86_32 && PCI
1757 On PCI systems, the BIOS can be used to detect the PCI devices and
1758 determine their configuration. However, some old PCI motherboards
1759 have BIOS bugs and may crash if this is done. Also, some embedded
1760 PCI-based systems don't have any BIOS at all. Linux can also try to
1761 detect the PCI hardware directly without using the BIOS.
1763 With this option, you can specify how Linux should detect the
1764 PCI devices. If you choose "BIOS", the BIOS will be used,
1765 if you choose "Direct", the BIOS won't be used, and if you
1766 choose "MMConfig", then PCI Express MMCONFIG will be used.
1767 If you choose "Any", the kernel will try MMCONFIG, then the
1768 direct access method and falls back to the BIOS if that doesn't
1769 work. If unsure, go with the default, which is "Any".
1774 config PCI_GOMMCONFIG
1791 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1793 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1796 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1800 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1804 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1811 bool "Support mmconfig PCI config space access"
1812 depends on X86_64 && PCI && ACPI
1815 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1816 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1818 DMA remapping (DMAR) devices support enables independent address
1819 translations for Direct Memory Access (DMA) from devices.
1820 These DMA remapping devices are reported via ACPI tables
1821 and include PCI device scope covered by these DMA
1824 config DMAR_DEFAULT_ON
1826 prompt "Enable DMA Remapping Devices by default"
1829 Selecting this option will enable a DMAR device at boot time if
1830 one is found. If this option is not selected, DMAR support can
1831 be enabled by passing intel_iommu=on to the kernel. It is
1832 recommended you say N here while the DMAR code remains
1837 prompt "Support for Graphics workaround"
1840 Current Graphics drivers tend to use physical address
1841 for DMA and avoid using DMA APIs. Setting this config
1842 option permits the IOMMU driver to set a unity map for
1843 all the OS-visible memory. Hence the driver can continue
1844 to use physical addresses for DMA.
1846 config DMAR_FLOPPY_WA
1850 Floppy disk drivers are know to bypass DMA API calls
1851 thereby failing to work when IOMMU is enabled. This
1852 workaround will setup a 1:1 mapping for the first
1853 16M to make floppy (an ISA device) work.
1856 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1857 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1860 Supports Interrupt remapping for IO-APIC and MSI devices.
1861 To use x2apic mode in the CPU's which support x2APIC enhancements or
1862 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1864 source "drivers/pci/pcie/Kconfig"
1866 source "drivers/pci/Kconfig"
1868 # x86_64 have no ISA slots, but do have ISA-style DMA.
1877 Find out whether you have ISA slots on your motherboard. ISA is the
1878 name of a bus system, i.e. the way the CPU talks to the other stuff
1879 inside your box. Other bus systems are PCI, EISA, MicroChannel
1880 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1881 newer boards don't support it. If you have ISA, say Y, otherwise N.
1887 The Extended Industry Standard Architecture (EISA) bus was
1888 developed as an open alternative to the IBM MicroChannel bus.
1890 The EISA bus provided some of the features of the IBM MicroChannel
1891 bus while maintaining backward compatibility with cards made for
1892 the older ISA bus. The EISA bus saw limited use between 1988 and
1893 1995 when it was made obsolete by the PCI bus.
1895 Say Y here if you are building a kernel for an EISA-based machine.
1899 source "drivers/eisa/Kconfig"
1904 MicroChannel Architecture is found in some IBM PS/2 machines and
1905 laptops. It is a bus system similar to PCI or ISA. See
1906 <file:Documentation/mca.txt> (and especially the web page given
1907 there) before attempting to build an MCA bus kernel.
1909 source "drivers/mca/Kconfig"
1912 tristate "NatSemi SCx200 support"
1914 This provides basic support for National Semiconductor's
1915 (now AMD's) Geode processors. The driver probes for the
1916 PCI-IDs of several on-chip devices, so its a good dependency
1917 for other scx200_* drivers.
1919 If compiled as a module, the driver is named scx200.
1921 config SCx200HR_TIMER
1922 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1923 depends on SCx200 && GENERIC_TIME
1926 This driver provides a clocksource built upon the on-chip
1927 27MHz high-resolution timer. Its also a workaround for
1928 NSC Geode SC-1100's buggy TSC, which loses time when the
1929 processor goes idle (as is done by the scheduler). The
1930 other workaround is idle=poll boot option.
1932 config GEODE_MFGPT_TIMER
1934 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1935 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1937 This driver provides a clock event source based on the MFGPT
1938 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1939 MFGPTs have a better resolution and max interval than the
1940 generic PIT, and are suitable for use as high-res timers.
1943 bool "One Laptop Per Child support"
1946 Add support for detecting the unique features of the OLPC
1953 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1955 source "drivers/pcmcia/Kconfig"
1957 source "drivers/pci/hotplug/Kconfig"
1962 menu "Executable file formats / Emulations"
1964 source "fs/Kconfig.binfmt"
1966 config IA32_EMULATION
1967 bool "IA32 Emulation"
1969 select COMPAT_BINFMT_ELF
1971 Include code to run 32-bit programs under a 64-bit kernel. You should
1972 likely turn this on, unless you're 100% sure that you don't have any
1973 32-bit programs left.
1976 tristate "IA32 a.out support"
1977 depends on IA32_EMULATION
1979 Support old a.out binaries in the 32bit emulation.
1983 depends on IA32_EMULATION
1985 config COMPAT_FOR_U64_ALIGNMENT
1989 config SYSVIPC_COMPAT
1991 depends on COMPAT && SYSVIPC
1996 config HAVE_ATOMIC_IOMAP
2000 source "net/Kconfig"
2002 source "drivers/Kconfig"
2004 source "drivers/firmware/Kconfig"
2008 source "arch/x86/Kconfig.debug"
2010 source "security/Kconfig"
2012 source "crypto/Kconfig"
2014 source "arch/x86/kvm/Kconfig"
2016 source "lib/Kconfig"
projects / linux-2.6 / blob