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
145 config ARCH_SUSPEND_POSSIBLE
152 config ARCH_POPULATES_NODE_MAP
159 config ARCH_SUPPORTS_OPTIMIZED_INLINING
162 # Use the generic interrupt handling code in kernel/irq/:
163 config GENERIC_HARDIRQS
167 config GENERIC_IRQ_PROBE
171 config GENERIC_PENDING_IRQ
173 depends on GENERIC_HARDIRQS && SMP
176 config USE_GENERIC_SMP_HELPERS
182 depends on X86_32 && SMP
186 depends on X86_64 && SMP
193 config X86_TRAMPOLINE
195 depends on SMP || (64BIT && ACPI_SLEEP)
200 source "init/Kconfig"
201 source "kernel/Kconfig.freezer"
203 menu "Processor type and features"
205 source "kernel/time/Kconfig"
208 bool "Symmetric multi-processing support"
210 This enables support for systems with more than one CPU. If you have
211 a system with only one CPU, like most personal computers, say N. If
212 you have a system with more than one CPU, say Y.
214 If you say N here, the kernel will run on single and multiprocessor
215 machines, but will use only one CPU of a multiprocessor machine. If
216 you say Y here, the kernel will run on many, but not all,
217 singleprocessor machines. On a singleprocessor machine, the kernel
218 will run faster if you say N here.
220 Note that if you say Y here and choose architecture "586" or
221 "Pentium" under "Processor family", the kernel will not work on 486
222 architectures. Similarly, multiprocessor kernels for the "PPro"
223 architecture may not work on all Pentium based boards.
225 People using multiprocessor machines who say Y here should also say
226 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
227 Management" code will be disabled if you say Y here.
229 See also <file:Documentation/i386/IO-APIC.txt>,
230 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
231 <http://www.tldp.org/docs.html#howto>.
233 If you don't know what to do here, say N.
236 bool "Support sparse irq numbering"
237 depends on PCI_MSI || HT_IRQ
239 This enables support for sparse irqs. This is useful for distro
240 kernels that want to define a high CONFIG_NR_CPUS value but still
241 want to have low kernel memory footprint on smaller machines.
243 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
244 out the irq_desc[] array in a more NUMA-friendly way. )
246 If you don't know what to do here, say N.
248 config NUMA_MIGRATE_IRQ_DESC
249 bool "Move irq desc when changing irq smp_affinity"
250 depends on SPARSE_IRQ && NUMA
253 This enables moving irq_desc to cpu/node that irq will use handled.
255 If you don't know what to do here, say N.
258 bool "Enable MPS table" if ACPI
260 depends on X86_LOCAL_APIC
262 For old smp systems that do not have proper acpi support. Newer systems
263 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
266 prompt "Subarchitecture Type"
272 Choose this option if your computer is a standard PC or compatible.
274 config X86_GENERICARCH
275 bool "Generic architecture"
278 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
279 subarchitectures. It is intended for a generic binary kernel.
280 if you select them all, kernel will probe it one by one. and will
286 bool "NUMAQ (IBM/Sequent)"
287 depends on SMP && X86_32 && PCI && X86_MPPARSE
290 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
291 NUMA multiquad box. This changes the way that processors are
292 bootstrapped, and uses Clustered Logical APIC addressing mode instead
293 of Flat Logical. You will need a new lynxer.elf file to flash your
294 firmware with - send email to <Martin.Bligh@us.ibm.com>.
297 bool "Summit/EXA (IBM x440)"
298 depends on X86_32 && SMP
300 This option is needed for IBM systems that use the Summit/EXA chipset.
301 In particular, it is needed for the x440.
304 bool "Support for Unisys ES7000 IA32 series"
305 depends on X86_32 && SMP
307 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
308 supposed to run on an IA32-based Unisys ES7000 system.
311 bool "Support for big SMP systems with more than 8 CPUs"
312 depends on X86_32 && SMP
314 This option is needed for the systems that have more than 8 CPUs
315 and if the system is not of any sub-arch type above.
320 bool "Support for ScaleMP vSMP"
322 depends on X86_64 && PCI
324 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
325 supposed to run on these EM64T-based machines. Only choose this option
326 if you have one of these machines.
330 config X86_NON_STANDARD
331 bool "Support for non-standard x86 platforms"
333 If you disable this option then the kernel will only support
334 standard PC platforms. (which covers the vast majority of
337 If you enable this option then you'll be able to select a number
338 of less common non-PC x86 platforms: VisWS, RDC321, SGI/UV.
340 If you have one of these systems, or if you want to build a
341 generic distribution kernel, say Y here - otherwise say N.
344 bool "SGI 320/540 (Visual Workstation)"
345 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
346 depends on X86_NON_STANDARD
348 The SGI Visual Workstation series is an IA32-based workstation
349 based on SGI systems chips with some legacy PC hardware attached.
351 Say Y here to create a kernel to run on the SGI 320 or 540.
353 A kernel compiled for the Visual Workstation will run on general
354 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
357 bool "RDC R-321x SoC"
359 depends on X86_NON_STANDARD
361 select X86_REBOOTFIXUPS
363 This option is needed for RDC R-321x system-on-chip, also known
365 If you don't have one of these chips, you should say N here.
368 bool "SGI Ultraviolet"
370 depends on X86_NON_STANDARD
372 This option is needed in order to support SGI Ultraviolet systems.
373 If you don't have one of these, you should say N here.
378 depends on X86_NON_STANDARD
380 Select this for an AMD Elan processor.
382 Do not use this option for K6/Athlon/Opteron processors!
384 If unsure, choose "PC-compatible" instead.
388 depends on X86_32 && SMP && !PCI && BROKEN
389 depends on X86_NON_STANDARD
391 Voyager is an MCA-based 32-way capable SMP architecture proprietary
392 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
396 If you do not specifically know you have a Voyager based machine,
397 say N here, otherwise the kernel you build will not be bootable.
399 config SCHED_OMIT_FRAME_POINTER
401 prompt "Single-depth WCHAN output"
404 Calculate simpler /proc/<PID>/wchan values. If this option
405 is disabled then wchan values will recurse back to the
406 caller function. This provides more accurate wchan values,
407 at the expense of slightly more scheduling overhead.
409 If in doubt, say "Y".
411 menuconfig PARAVIRT_GUEST
412 bool "Paravirtualized guest support"
414 Say Y here to get to see options related to running Linux under
415 various hypervisors. This option alone does not add any kernel code.
417 If you say N, all options in this submenu will be skipped and disabled.
421 source "arch/x86/xen/Kconfig"
424 bool "VMI Guest support"
428 VMI provides a paravirtualized interface to the VMware ESX server
429 (it could be used by other hypervisors in theory too, but is not
430 at the moment), by linking the kernel to a GPL-ed ROM module
431 provided by the hypervisor.
434 bool "KVM paravirtualized clock"
436 select PARAVIRT_CLOCK
438 Turning on this option will allow you to run a paravirtualized clock
439 when running over the KVM hypervisor. Instead of relying on a PIT
440 (or probably other) emulation by the underlying device model, the host
441 provides the guest with timing infrastructure such as time of day, and
445 bool "KVM Guest support"
448 This option enables various optimizations for running under the KVM
451 source "arch/x86/lguest/Kconfig"
454 bool "Enable paravirtualization code"
456 This changes the kernel so it can modify itself when it is run
457 under a hypervisor, potentially improving performance significantly
458 over full virtualization. However, when run without a hypervisor
459 the kernel is theoretically slower and slightly larger.
461 config PARAVIRT_CLOCK
467 config PARAVIRT_DEBUG
468 bool "paravirt-ops debugging"
469 depends on PARAVIRT && DEBUG_KERNEL
471 Enable to debug paravirt_ops internals. Specifically, BUG if
472 a paravirt_op is missing when it is called.
477 This option adds a kernel parameter 'memtest', which allows memtest
479 memtest=0, mean disabled; -- default
480 memtest=1, mean do 1 test pattern;
482 memtest=4, mean do 4 test patterns.
483 If you are unsure how to answer this question, answer N.
485 config X86_SUMMIT_NUMA
487 depends on X86_32 && NUMA && X86_GENERICARCH
489 config X86_CYCLONE_TIMER
491 depends on X86_GENERICARCH
493 source "arch/x86/Kconfig.cpu"
497 prompt "HPET Timer Support" if X86_32
499 Use the IA-PC HPET (High Precision Event Timer) to manage
500 time in preference to the PIT and RTC, if a HPET is
502 HPET is the next generation timer replacing legacy 8254s.
503 The HPET provides a stable time base on SMP
504 systems, unlike the TSC, but it is more expensive to access,
505 as it is off-chip. You can find the HPET spec at
506 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
508 You can safely choose Y here. However, HPET will only be
509 activated if the platform and the BIOS support this feature.
510 Otherwise the 8254 will be used for timing services.
512 Choose N to continue using the legacy 8254 timer.
514 config HPET_EMULATE_RTC
516 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
518 # Mark as embedded because too many people got it wrong.
519 # The code disables itself when not needed.
522 bool "Enable DMI scanning" if EMBEDDED
524 Enabled scanning of DMI to identify machine quirks. Say Y
525 here unless you have verified that your setup is not
526 affected by entries in the DMI blacklist. Required by PNP
530 bool "GART IOMMU support" if EMBEDDED
534 depends on X86_64 && PCI
536 Support for full DMA access of devices with 32bit memory access only
537 on systems with more than 3GB. This is usually needed for USB,
538 sound, many IDE/SATA chipsets and some other devices.
539 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
540 based hardware IOMMU and a software bounce buffer based IOMMU used
541 on Intel systems and as fallback.
542 The code is only active when needed (enough memory and limited
543 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
547 bool "IBM Calgary IOMMU support"
549 depends on X86_64 && PCI && EXPERIMENTAL
551 Support for hardware IOMMUs in IBM's xSeries x366 and x460
552 systems. Needed to run systems with more than 3GB of memory
553 properly with 32-bit PCI devices that do not support DAC
554 (Double Address Cycle). Calgary also supports bus level
555 isolation, where all DMAs pass through the IOMMU. This
556 prevents them from going anywhere except their intended
557 destination. This catches hard-to-find kernel bugs and
558 mis-behaving drivers and devices that do not use the DMA-API
559 properly to set up their DMA buffers. The IOMMU can be
560 turned off at boot time with the iommu=off parameter.
561 Normally the kernel will make the right choice by itself.
564 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
566 prompt "Should Calgary be enabled by default?"
567 depends on CALGARY_IOMMU
569 Should Calgary be enabled by default? if you choose 'y', Calgary
570 will be used (if it exists). If you choose 'n', Calgary will not be
571 used even if it exists. If you choose 'n' and would like to use
572 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
576 bool "AMD IOMMU support"
579 depends on X86_64 && PCI && ACPI
581 With this option you can enable support for AMD IOMMU hardware in
582 your system. An IOMMU is a hardware component which provides
583 remapping of DMA memory accesses from devices. With an AMD IOMMU you
584 can isolate the the DMA memory of different devices and protect the
585 system from misbehaving device drivers or hardware.
587 You can find out if your system has an AMD IOMMU if you look into
588 your BIOS for an option to enable it or if you have an IVRS ACPI
591 config AMD_IOMMU_STATS
592 bool "Export AMD IOMMU statistics to debugfs"
596 This option enables code in the AMD IOMMU driver to collect various
597 statistics about whats happening in the driver and exports that
598 information to userspace via debugfs.
601 # need this always selected by IOMMU for the VIA workaround
605 Support for software bounce buffers used on x86-64 systems
606 which don't have a hardware IOMMU (e.g. the current generation
607 of Intel's x86-64 CPUs). Using this PCI devices which can only
608 access 32-bits of memory can be used on systems with more than
609 3 GB of memory. If unsure, say Y.
612 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
615 def_bool (AMD_IOMMU || DMAR)
618 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
619 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
620 select CPUMASK_OFFSTACK
623 Configure maximum number of CPUS and NUMA Nodes for this architecture.
627 int "Maximum number of CPUs" if SMP && !MAXSMP
628 range 2 512 if SMP && !MAXSMP
630 default "4096" if MAXSMP
631 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
634 This allows you to specify the maximum number of CPUs which this
635 kernel will support. The maximum supported value is 512 and the
636 minimum value which makes sense is 2.
638 This is purely to save memory - each supported CPU adds
639 approximately eight kilobytes to the kernel image.
642 bool "SMT (Hyperthreading) scheduler support"
645 SMT scheduler support improves the CPU scheduler's decision making
646 when dealing with Intel Pentium 4 chips with HyperThreading at a
647 cost of slightly increased overhead in some places. If unsure say
652 prompt "Multi-core scheduler support"
655 Multi-core scheduler support improves the CPU scheduler's decision
656 making when dealing with multi-core CPU chips at a cost of slightly
657 increased overhead in some places. If unsure say N here.
659 source "kernel/Kconfig.preempt"
662 bool "Local APIC support on uniprocessors"
663 depends on X86_32 && !SMP && !X86_GENERICARCH
665 A local APIC (Advanced Programmable Interrupt Controller) is an
666 integrated interrupt controller in the CPU. If you have a single-CPU
667 system which has a processor with a local APIC, you can say Y here to
668 enable and use it. If you say Y here even though your machine doesn't
669 have a local APIC, then the kernel will still run with no slowdown at
670 all. The local APIC supports CPU-generated self-interrupts (timer,
671 performance counters), and the NMI watchdog which detects hard
675 bool "IO-APIC support on uniprocessors"
676 depends on X86_UP_APIC
678 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
679 SMP-capable replacement for PC-style interrupt controllers. Most
680 SMP systems and many recent uniprocessor systems have one.
682 If you have a single-CPU system with an IO-APIC, you can say Y here
683 to use it. If you say Y here even though your machine doesn't have
684 an IO-APIC, then the kernel will still run with no slowdown at all.
686 config X86_LOCAL_APIC
688 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
692 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
694 config X86_VISWS_APIC
696 depends on X86_32 && X86_VISWS
698 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
699 bool "Reroute for broken boot IRQs"
701 depends on X86_IO_APIC
703 This option enables a workaround that fixes a source of
704 spurious interrupts. This is recommended when threaded
705 interrupt handling is used on systems where the generation of
706 superfluous "boot interrupts" cannot be disabled.
708 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
709 entry in the chipset's IO-APIC is masked (as, e.g. the RT
710 kernel does during interrupt handling). On chipsets where this
711 boot IRQ generation cannot be disabled, this workaround keeps
712 the original IRQ line masked so that only the equivalent "boot
713 IRQ" is delivered to the CPUs. The workaround also tells the
714 kernel to set up the IRQ handler on the boot IRQ line. In this
715 way only one interrupt is delivered to the kernel. Otherwise
716 the spurious second interrupt may cause the kernel to bring
717 down (vital) interrupt lines.
719 Only affects "broken" chipsets. Interrupt sharing may be
720 increased on these systems.
723 bool "Machine Check Exception"
725 Machine Check Exception support allows the processor to notify the
726 kernel if it detects a problem (e.g. overheating, component failure).
727 The action the kernel takes depends on the severity of the problem,
728 ranging from a warning message on the console, to halting the machine.
729 Your processor must be a Pentium or newer to support this - check the
730 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
731 have a design flaw which leads to false MCE events - hence MCE is
732 disabled on all P5 processors, unless explicitly enabled with "mce"
733 as a boot argument. Similarly, if MCE is built in and creates a
734 problem on some new non-standard machine, you can boot with "nomce"
735 to disable it. MCE support simply ignores non-MCE processors like
736 the 386 and 486, so nearly everyone can say Y here.
740 prompt "Intel MCE features"
741 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
743 Additional support for intel specific MCE features such as
748 prompt "AMD MCE features"
749 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
751 Additional support for AMD specific MCE features such as
752 the DRAM Error Threshold.
754 config X86_MCE_NONFATAL
755 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
756 depends on X86_32 && X86_MCE
758 Enabling this feature starts a timer that triggers every 5 seconds which
759 will look at the machine check registers to see if anything happened.
760 Non-fatal problems automatically get corrected (but still logged).
761 Disable this if you don't want to see these messages.
762 Seeing the messages this option prints out may be indicative of dying
763 or out-of-spec (ie, overclocked) hardware.
764 This option only does something on certain CPUs.
765 (AMD Athlon/Duron and Intel Pentium 4)
767 config X86_MCE_P4THERMAL
768 bool "check for P4 thermal throttling interrupt."
769 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
771 Enabling this feature will cause a message to be printed when the P4
772 enters thermal throttling.
775 bool "Enable VM86 support" if EMBEDDED
779 This option is required by programs like DOSEMU to run 16-bit legacy
780 code on X86 processors. It also may be needed by software like
781 XFree86 to initialize some video cards via BIOS. Disabling this
782 option saves about 6k.
785 tristate "Toshiba Laptop support"
788 This adds a driver to safely access the System Management Mode of
789 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
790 not work on models with a Phoenix BIOS. The System Management Mode
791 is used to set the BIOS and power saving options on Toshiba portables.
793 For information on utilities to make use of this driver see the
794 Toshiba Linux utilities web site at:
795 <http://www.buzzard.org.uk/toshiba/>.
797 Say Y if you intend to run this kernel on a Toshiba portable.
801 tristate "Dell laptop support"
803 This adds a driver to safely access the System Management Mode
804 of the CPU on the Dell Inspiron 8000. The System Management Mode
805 is used to read cpu temperature and cooling fan status and to
806 control the fans on the I8K portables.
808 This driver has been tested only on the Inspiron 8000 but it may
809 also work with other Dell laptops. You can force loading on other
810 models by passing the parameter `force=1' to the module. Use at
813 For information on utilities to make use of this driver see the
814 I8K Linux utilities web site at:
815 <http://people.debian.org/~dz/i8k/>
817 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
820 config X86_REBOOTFIXUPS
821 bool "Enable X86 board specific fixups for reboot"
824 This enables chipset and/or board specific fixups to be done
825 in order to get reboot to work correctly. This is only needed on
826 some combinations of hardware and BIOS. The symptom, for which
827 this config is intended, is when reboot ends with a stalled/hung
830 Currently, the only fixup is for the Geode machines using
831 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
833 Say Y if you want to enable the fixup. Currently, it's safe to
834 enable this option even if you don't need it.
838 tristate "/dev/cpu/microcode - microcode support"
841 If you say Y here, you will be able to update the microcode on
842 certain Intel and AMD processors. The Intel support is for the
843 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
844 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
845 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
846 You will obviously need the actual microcode binary data itself
847 which is not shipped with the Linux kernel.
849 This option selects the general module only, you need to select
850 at least one vendor specific module as well.
852 To compile this driver as a module, choose M here: the
853 module will be called microcode.
855 config MICROCODE_INTEL
856 bool "Intel microcode patch loading support"
861 This options enables microcode patch loading support for Intel
864 For latest news and information on obtaining all the required
865 Intel ingredients for this driver, check:
866 <http://www.urbanmyth.org/microcode/>.
869 bool "AMD microcode patch loading support"
873 If you select this option, microcode patch loading support for AMD
874 processors will be enabled.
876 config MICROCODE_OLD_INTERFACE
881 tristate "/dev/cpu/*/msr - Model-specific register support"
883 This device gives privileged processes access to the x86
884 Model-Specific Registers (MSRs). It is a character device with
885 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
886 MSR accesses are directed to a specific CPU on multi-processor
890 tristate "/dev/cpu/*/cpuid - CPU information support"
892 This device gives processes access to the x86 CPUID instruction to
893 be executed on a specific processor. It is a character device
894 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
898 prompt "High Memory Support"
899 default HIGHMEM4G if !X86_NUMAQ
900 default HIGHMEM64G if X86_NUMAQ
905 depends on !X86_NUMAQ
907 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
908 However, the address space of 32-bit x86 processors is only 4
909 Gigabytes large. That means that, if you have a large amount of
910 physical memory, not all of it can be "permanently mapped" by the
911 kernel. The physical memory that's not permanently mapped is called
914 If you are compiling a kernel which will never run on a machine with
915 more than 1 Gigabyte total physical RAM, answer "off" here (default
916 choice and suitable for most users). This will result in a "3GB/1GB"
917 split: 3GB are mapped so that each process sees a 3GB virtual memory
918 space and the remaining part of the 4GB virtual memory space is used
919 by the kernel to permanently map as much physical memory as
922 If the machine has between 1 and 4 Gigabytes physical RAM, then
925 If more than 4 Gigabytes is used then answer "64GB" here. This
926 selection turns Intel PAE (Physical Address Extension) mode on.
927 PAE implements 3-level paging on IA32 processors. PAE is fully
928 supported by Linux, PAE mode is implemented on all recent Intel
929 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
930 then the kernel will not boot on CPUs that don't support PAE!
932 The actual amount of total physical memory will either be
933 auto detected or can be forced by using a kernel command line option
934 such as "mem=256M". (Try "man bootparam" or see the documentation of
935 your boot loader (lilo or loadlin) about how to pass options to the
936 kernel at boot time.)
938 If unsure, say "off".
942 depends on !X86_NUMAQ
944 Select this if you have a 32-bit processor and between 1 and 4
945 gigabytes of physical RAM.
949 depends on !M386 && !M486
952 Select this if you have a 32-bit processor and more than 4
953 gigabytes of physical RAM.
958 depends on EXPERIMENTAL
959 prompt "Memory split" if EMBEDDED
963 Select the desired split between kernel and user memory.
965 If the address range available to the kernel is less than the
966 physical memory installed, the remaining memory will be available
967 as "high memory". Accessing high memory is a little more costly
968 than low memory, as it needs to be mapped into the kernel first.
969 Note that increasing the kernel address space limits the range
970 available to user programs, making the address space there
971 tighter. Selecting anything other than the default 3G/1G split
972 will also likely make your kernel incompatible with binary-only
975 If you are not absolutely sure what you are doing, leave this
979 bool "3G/1G user/kernel split"
980 config VMSPLIT_3G_OPT
982 bool "3G/1G user/kernel split (for full 1G low memory)"
984 bool "2G/2G user/kernel split"
985 config VMSPLIT_2G_OPT
987 bool "2G/2G user/kernel split (for full 2G low memory)"
989 bool "1G/3G user/kernel split"
994 default 0xB0000000 if VMSPLIT_3G_OPT
995 default 0x80000000 if VMSPLIT_2G
996 default 0x78000000 if VMSPLIT_2G_OPT
997 default 0x40000000 if VMSPLIT_1G
1003 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1006 bool "PAE (Physical Address Extension) Support"
1007 depends on X86_32 && !HIGHMEM4G
1009 PAE is required for NX support, and furthermore enables
1010 larger swapspace support for non-overcommit purposes. It
1011 has the cost of more pagetable lookup overhead, and also
1012 consumes more pagetable space per process.
1014 config ARCH_PHYS_ADDR_T_64BIT
1015 def_bool X86_64 || X86_PAE
1017 config DIRECT_GBPAGES
1018 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1022 Allow the kernel linear mapping to use 1GB pages on CPUs that
1023 support it. This can improve the kernel's performance a tiny bit by
1024 reducing TLB pressure. If in doubt, say "Y".
1026 # Common NUMA Features
1028 bool "Numa Memory Allocation and Scheduler Support"
1030 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1032 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1034 Enable NUMA (Non Uniform Memory Access) support.
1036 The kernel will try to allocate memory used by a CPU on the
1037 local memory controller of the CPU and add some more
1038 NUMA awareness to the kernel.
1040 For 64-bit this is recommended if the system is Intel Core i7
1041 (or later), AMD Opteron, or EM64T NUMA.
1043 For 32-bit this is only needed on (rare) 32-bit-only platforms
1044 that support NUMA topologies, such as NUMAQ / Summit, or if you
1045 boot a 32-bit kernel on a 64-bit NUMA platform.
1047 Otherwise, you should say N.
1049 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1050 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1054 prompt "Old style AMD Opteron NUMA detection"
1055 depends on X86_64 && NUMA && PCI
1057 Enable K8 NUMA node topology detection. You should say Y here if
1058 you have a multi processor AMD K8 system. This uses an old
1059 method to read the NUMA configuration directly from the builtin
1060 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1061 instead, which also takes priority if both are compiled in.
1063 config X86_64_ACPI_NUMA
1065 prompt "ACPI NUMA detection"
1066 depends on X86_64 && NUMA && ACPI && PCI
1069 Enable ACPI SRAT based node topology detection.
1071 # Some NUMA nodes have memory ranges that span
1072 # other nodes. Even though a pfn is valid and
1073 # between a node's start and end pfns, it may not
1074 # reside on that node. See memmap_init_zone()
1076 config NODES_SPAN_OTHER_NODES
1078 depends on X86_64_ACPI_NUMA
1081 bool "NUMA emulation"
1082 depends on X86_64 && NUMA
1084 Enable NUMA emulation. A flat machine will be split
1085 into virtual nodes when booted with "numa=fake=N", where N is the
1086 number of nodes. This is only useful for debugging.
1089 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1091 default "9" if MAXSMP
1092 default "6" if X86_64
1093 default "4" if X86_NUMAQ
1095 depends on NEED_MULTIPLE_NODES
1097 Specify the maximum number of NUMA Nodes available on the target
1098 system. Increases memory reserved to accomodate various tables.
1100 config HAVE_ARCH_BOOTMEM_NODE
1102 depends on X86_32 && NUMA
1104 config ARCH_HAVE_MEMORY_PRESENT
1106 depends on X86_32 && DISCONTIGMEM
1108 config NEED_NODE_MEMMAP_SIZE
1110 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1112 config HAVE_ARCH_ALLOC_REMAP
1114 depends on X86_32 && NUMA
1116 config ARCH_FLATMEM_ENABLE
1118 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1120 config ARCH_DISCONTIGMEM_ENABLE
1122 depends on NUMA && X86_32
1124 config ARCH_DISCONTIGMEM_DEFAULT
1126 depends on NUMA && X86_32
1128 config ARCH_SPARSEMEM_DEFAULT
1132 config ARCH_SPARSEMEM_ENABLE
1134 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1135 select SPARSEMEM_STATIC if X86_32
1136 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1138 config ARCH_SELECT_MEMORY_MODEL
1140 depends on ARCH_SPARSEMEM_ENABLE
1142 config ARCH_MEMORY_PROBE
1144 depends on MEMORY_HOTPLUG
1149 bool "Allocate 3rd-level pagetables from highmem"
1150 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1152 The VM uses one page table entry for each page of physical memory.
1153 For systems with a lot of RAM, this can be wasteful of precious
1154 low memory. Setting this option will put user-space page table
1155 entries in high memory.
1157 config X86_CHECK_BIOS_CORRUPTION
1158 bool "Check for low memory corruption"
1160 Periodically check for memory corruption in low memory, which
1161 is suspected to be caused by BIOS. Even when enabled in the
1162 configuration, it is disabled at runtime. Enable it by
1163 setting "memory_corruption_check=1" on the kernel command
1164 line. By default it scans the low 64k of memory every 60
1165 seconds; see the memory_corruption_check_size and
1166 memory_corruption_check_period parameters in
1167 Documentation/kernel-parameters.txt to adjust this.
1169 When enabled with the default parameters, this option has
1170 almost no overhead, as it reserves a relatively small amount
1171 of memory and scans it infrequently. It both detects corruption
1172 and prevents it from affecting the running system.
1174 It is, however, intended as a diagnostic tool; if repeatable
1175 BIOS-originated corruption always affects the same memory,
1176 you can use memmap= to prevent the kernel from using that
1179 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1180 bool "Set the default setting of memory_corruption_check"
1181 depends on X86_CHECK_BIOS_CORRUPTION
1184 Set whether the default state of memory_corruption_check is
1187 config X86_RESERVE_LOW_64K
1188 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1191 Reserve the first 64K of physical RAM on BIOSes that are known
1192 to potentially corrupt that memory range. A numbers of BIOSes are
1193 known to utilize this area during suspend/resume, so it must not
1194 be used by the kernel.
1196 Set this to N if you are absolutely sure that you trust the BIOS
1197 to get all its memory reservations and usages right.
1199 If you have doubts about the BIOS (e.g. suspend/resume does not
1200 work or there's kernel crashes after certain hardware hotplug
1201 events) and it's not AMI or Phoenix, then you might want to enable
1202 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1203 corruption patterns.
1207 config MATH_EMULATION
1209 prompt "Math emulation" if X86_32
1211 Linux can emulate a math coprocessor (used for floating point
1212 operations) if you don't have one. 486DX and Pentium processors have
1213 a math coprocessor built in, 486SX and 386 do not, unless you added
1214 a 487DX or 387, respectively. (The messages during boot time can
1215 give you some hints here ["man dmesg"].) Everyone needs either a
1216 coprocessor or this emulation.
1218 If you don't have a math coprocessor, you need to say Y here; if you
1219 say Y here even though you have a coprocessor, the coprocessor will
1220 be used nevertheless. (This behavior can be changed with the kernel
1221 command line option "no387", which comes handy if your coprocessor
1222 is broken. Try "man bootparam" or see the documentation of your boot
1223 loader (lilo or loadlin) about how to pass options to the kernel at
1224 boot time.) This means that it is a good idea to say Y here if you
1225 intend to use this kernel on different machines.
1227 More information about the internals of the Linux math coprocessor
1228 emulation can be found in <file:arch/x86/math-emu/README>.
1230 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1231 kernel, it won't hurt.
1234 bool "MTRR (Memory Type Range Register) support"
1236 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1237 the Memory Type Range Registers (MTRRs) may be used to control
1238 processor access to memory ranges. This is most useful if you have
1239 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1240 allows bus write transfers to be combined into a larger transfer
1241 before bursting over the PCI/AGP bus. This can increase performance
1242 of image write operations 2.5 times or more. Saying Y here creates a
1243 /proc/mtrr file which may be used to manipulate your processor's
1244 MTRRs. Typically the X server should use this.
1246 This code has a reasonably generic interface so that similar
1247 control registers on other processors can be easily supported
1250 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1251 Registers (ARRs) which provide a similar functionality to MTRRs. For
1252 these, the ARRs are used to emulate the MTRRs.
1253 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1254 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1255 write-combining. All of these processors are supported by this code
1256 and it makes sense to say Y here if you have one of them.
1258 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1259 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1260 can lead to all sorts of problems, so it's good to say Y here.
1262 You can safely say Y even if your machine doesn't have MTRRs, you'll
1263 just add about 9 KB to your kernel.
1265 See <file:Documentation/x86/mtrr.txt> for more information.
1267 config MTRR_SANITIZER
1269 prompt "MTRR cleanup support"
1272 Convert MTRR layout from continuous to discrete, so X drivers can
1273 add writeback entries.
1275 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1276 The largest mtrr entry size for a continous block can be set with
1281 config MTRR_SANITIZER_ENABLE_DEFAULT
1282 int "MTRR cleanup enable value (0-1)"
1285 depends on MTRR_SANITIZER
1287 Enable mtrr cleanup default value
1289 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1290 int "MTRR cleanup spare reg num (0-7)"
1293 depends on MTRR_SANITIZER
1295 mtrr cleanup spare entries default, it can be changed via
1296 mtrr_spare_reg_nr=N on the kernel command line.
1300 prompt "x86 PAT support"
1303 Use PAT attributes to setup page level cache control.
1305 PATs are the modern equivalents of MTRRs and are much more
1306 flexible than MTRRs.
1308 Say N here if you see bootup problems (boot crash, boot hang,
1309 spontaneous reboots) or a non-working video driver.
1314 bool "EFI runtime service support"
1317 This enables the kernel to use EFI runtime services that are
1318 available (such as the EFI variable services).
1320 This option is only useful on systems that have EFI firmware.
1321 In addition, you should use the latest ELILO loader available
1322 at <http://elilo.sourceforge.net> in order to take advantage
1323 of EFI runtime services. However, even with this option, the
1324 resultant kernel should continue to boot on existing non-EFI
1329 prompt "Enable seccomp to safely compute untrusted bytecode"
1331 This kernel feature is useful for number crunching applications
1332 that may need to compute untrusted bytecode during their
1333 execution. By using pipes or other transports made available to
1334 the process as file descriptors supporting the read/write
1335 syscalls, it's possible to isolate those applications in
1336 their own address space using seccomp. Once seccomp is
1337 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1338 and the task is only allowed to execute a few safe syscalls
1339 defined by each seccomp mode.
1341 If unsure, say Y. Only embedded should say N here.
1343 config CC_STACKPROTECTOR_ALL
1346 config CC_STACKPROTECTOR
1347 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1349 select CC_STACKPROTECTOR_ALL
1351 This option turns on the -fstack-protector GCC feature. This
1352 feature puts, at the beginning of functions, a canary value on
1353 the stack just before the return address, and validates
1354 the value just before actually returning. Stack based buffer
1355 overflows (that need to overwrite this return address) now also
1356 overwrite the canary, which gets detected and the attack is then
1357 neutralized via a kernel panic.
1359 This feature requires gcc version 4.2 or above, or a distribution
1360 gcc with the feature backported. Older versions are automatically
1361 detected and for those versions, this configuration option is
1362 ignored. (and a warning is printed during bootup)
1364 source kernel/Kconfig.hz
1367 bool "kexec system call"
1369 kexec is a system call that implements the ability to shutdown your
1370 current kernel, and to start another kernel. It is like a reboot
1371 but it is independent of the system firmware. And like a reboot
1372 you can start any kernel with it, not just Linux.
1374 The name comes from the similarity to the exec system call.
1376 It is an ongoing process to be certain the hardware in a machine
1377 is properly shutdown, so do not be surprised if this code does not
1378 initially work for you. It may help to enable device hotplugging
1379 support. As of this writing the exact hardware interface is
1380 strongly in flux, so no good recommendation can be made.
1383 bool "kernel crash dumps"
1384 depends on X86_64 || (X86_32 && HIGHMEM)
1386 Generate crash dump after being started by kexec.
1387 This should be normally only set in special crash dump kernels
1388 which are loaded in the main kernel with kexec-tools into
1389 a specially reserved region and then later executed after
1390 a crash by kdump/kexec. The crash dump kernel must be compiled
1391 to a memory address not used by the main kernel or BIOS using
1392 PHYSICAL_START, or it must be built as a relocatable image
1393 (CONFIG_RELOCATABLE=y).
1394 For more details see Documentation/kdump/kdump.txt
1397 bool "kexec jump (EXPERIMENTAL)"
1398 depends on EXPERIMENTAL
1399 depends on KEXEC && HIBERNATION && X86_32
1401 Jump between original kernel and kexeced kernel and invoke
1402 code in physical address mode via KEXEC
1404 config PHYSICAL_START
1405 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1406 default "0x1000000" if X86_NUMAQ
1407 default "0x200000" if X86_64
1410 This gives the physical address where the kernel is loaded.
1412 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1413 bzImage will decompress itself to above physical address and
1414 run from there. Otherwise, bzImage will run from the address where
1415 it has been loaded by the boot loader and will ignore above physical
1418 In normal kdump cases one does not have to set/change this option
1419 as now bzImage can be compiled as a completely relocatable image
1420 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1421 address. This option is mainly useful for the folks who don't want
1422 to use a bzImage for capturing the crash dump and want to use a
1423 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1424 to be specifically compiled to run from a specific memory area
1425 (normally a reserved region) and this option comes handy.
1427 So if you are using bzImage for capturing the crash dump, leave
1428 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1429 Otherwise if you plan to use vmlinux for capturing the crash dump
1430 change this value to start of the reserved region (Typically 16MB
1431 0x1000000). In other words, it can be set based on the "X" value as
1432 specified in the "crashkernel=YM@XM" command line boot parameter
1433 passed to the panic-ed kernel. Typically this parameter is set as
1434 crashkernel=64M@16M. Please take a look at
1435 Documentation/kdump/kdump.txt for more details about crash dumps.
1437 Usage of bzImage for capturing the crash dump is recommended as
1438 one does not have to build two kernels. Same kernel can be used
1439 as production kernel and capture kernel. Above option should have
1440 gone away after relocatable bzImage support is introduced. But it
1441 is present because there are users out there who continue to use
1442 vmlinux for dump capture. This option should go away down the
1445 Don't change this unless you know what you are doing.
1448 bool "Build a relocatable kernel (EXPERIMENTAL)"
1449 depends on EXPERIMENTAL
1451 This builds a kernel image that retains relocation information
1452 so it can be loaded someplace besides the default 1MB.
1453 The relocations tend to make the kernel binary about 10% larger,
1454 but are discarded at runtime.
1456 One use is for the kexec on panic case where the recovery kernel
1457 must live at a different physical address than the primary
1460 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1461 it has been loaded at and the compile time physical address
1462 (CONFIG_PHYSICAL_START) is ignored.
1464 config PHYSICAL_ALIGN
1466 prompt "Alignment value to which kernel should be aligned" if X86_32
1467 default "0x100000" if X86_32
1468 default "0x200000" if X86_64
1469 range 0x2000 0x400000
1471 This value puts the alignment restrictions on physical address
1472 where kernel is loaded and run from. Kernel is compiled for an
1473 address which meets above alignment restriction.
1475 If bootloader loads the kernel at a non-aligned address and
1476 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1477 address aligned to above value and run from there.
1479 If bootloader loads the kernel at a non-aligned address and
1480 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1481 load address and decompress itself to the address it has been
1482 compiled for and run from there. The address for which kernel is
1483 compiled already meets above alignment restrictions. Hence the
1484 end result is that kernel runs from a physical address meeting
1485 above alignment restrictions.
1487 Don't change this unless you know what you are doing.
1490 bool "Support for hot-pluggable CPUs"
1491 depends on SMP && HOTPLUG
1493 Say Y here to allow turning CPUs off and on. CPUs can be
1494 controlled through /sys/devices/system/cpu.
1495 ( Note: power management support will enable this option
1496 automatically on SMP systems. )
1497 Say N if you want to disable CPU hotplug.
1501 prompt "Compat VDSO support"
1502 depends on X86_32 || IA32_EMULATION
1504 Map the 32-bit VDSO to the predictable old-style address too.
1506 Say N here if you are running a sufficiently recent glibc
1507 version (2.3.3 or later), to remove the high-mapped
1508 VDSO mapping and to exclusively use the randomized VDSO.
1513 bool "Built-in kernel command line"
1516 Allow for specifying boot arguments to the kernel at
1517 build time. On some systems (e.g. embedded ones), it is
1518 necessary or convenient to provide some or all of the
1519 kernel boot arguments with the kernel itself (that is,
1520 to not rely on the boot loader to provide them.)
1522 To compile command line arguments into the kernel,
1523 set this option to 'Y', then fill in the
1524 the boot arguments in CONFIG_CMDLINE.
1526 Systems with fully functional boot loaders (i.e. non-embedded)
1527 should leave this option set to 'N'.
1530 string "Built-in kernel command string"
1531 depends on CMDLINE_BOOL
1534 Enter arguments here that should be compiled into the kernel
1535 image and used at boot time. If the boot loader provides a
1536 command line at boot time, it is appended to this string to
1537 form the full kernel command line, when the system boots.
1539 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1540 change this behavior.
1542 In most cases, the command line (whether built-in or provided
1543 by the boot loader) should specify the device for the root
1546 config CMDLINE_OVERRIDE
1547 bool "Built-in command line overrides boot loader arguments"
1549 depends on CMDLINE_BOOL
1551 Set this option to 'Y' to have the kernel ignore the boot loader
1552 command line, and use ONLY the built-in command line.
1554 This is used to work around broken boot loaders. This should
1555 be set to 'N' under normal conditions.
1559 config ARCH_ENABLE_MEMORY_HOTPLUG
1561 depends on X86_64 || (X86_32 && HIGHMEM)
1563 config ARCH_ENABLE_MEMORY_HOTREMOVE
1565 depends on MEMORY_HOTPLUG
1567 config HAVE_ARCH_EARLY_PFN_TO_NID
1571 menu "Power management and ACPI options"
1573 config ARCH_HIBERNATION_HEADER
1575 depends on X86_64 && HIBERNATION
1577 source "kernel/power/Kconfig"
1579 source "drivers/acpi/Kconfig"
1584 depends on APM || APM_MODULE
1587 tristate "APM (Advanced Power Management) BIOS support"
1588 depends on X86_32 && PM_SLEEP
1590 APM is a BIOS specification for saving power using several different
1591 techniques. This is mostly useful for battery powered laptops with
1592 APM compliant BIOSes. If you say Y here, the system time will be
1593 reset after a RESUME operation, the /proc/apm device will provide
1594 battery status information, and user-space programs will receive
1595 notification of APM "events" (e.g. battery status change).
1597 If you select "Y" here, you can disable actual use of the APM
1598 BIOS by passing the "apm=off" option to the kernel at boot time.
1600 Note that the APM support is almost completely disabled for
1601 machines with more than one CPU.
1603 In order to use APM, you will need supporting software. For location
1604 and more information, read <file:Documentation/power/pm.txt> and the
1605 Battery Powered Linux mini-HOWTO, available from
1606 <http://www.tldp.org/docs.html#howto>.
1608 This driver does not spin down disk drives (see the hdparm(8)
1609 manpage ("man 8 hdparm") for that), and it doesn't turn off
1610 VESA-compliant "green" monitors.
1612 This driver does not support the TI 4000M TravelMate and the ACER
1613 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1614 desktop machines also don't have compliant BIOSes, and this driver
1615 may cause those machines to panic during the boot phase.
1617 Generally, if you don't have a battery in your machine, there isn't
1618 much point in using this driver and you should say N. If you get
1619 random kernel OOPSes or reboots that don't seem to be related to
1620 anything, try disabling/enabling this option (or disabling/enabling
1623 Some other things you should try when experiencing seemingly random,
1626 1) make sure that you have enough swap space and that it is
1628 2) pass the "no-hlt" option to the kernel
1629 3) switch on floating point emulation in the kernel and pass
1630 the "no387" option to the kernel
1631 4) pass the "floppy=nodma" option to the kernel
1632 5) pass the "mem=4M" option to the kernel (thereby disabling
1633 all but the first 4 MB of RAM)
1634 6) make sure that the CPU is not over clocked.
1635 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1636 8) disable the cache from your BIOS settings
1637 9) install a fan for the video card or exchange video RAM
1638 10) install a better fan for the CPU
1639 11) exchange RAM chips
1640 12) exchange the motherboard.
1642 To compile this driver as a module, choose M here: the
1643 module will be called apm.
1647 config APM_IGNORE_USER_SUSPEND
1648 bool "Ignore USER SUSPEND"
1650 This option will ignore USER SUSPEND requests. On machines with a
1651 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1652 series notebooks, it is necessary to say Y because of a BIOS bug.
1654 config APM_DO_ENABLE
1655 bool "Enable PM at boot time"
1657 Enable APM features at boot time. From page 36 of the APM BIOS
1658 specification: "When disabled, the APM BIOS does not automatically
1659 power manage devices, enter the Standby State, enter the Suspend
1660 State, or take power saving steps in response to CPU Idle calls."
1661 This driver will make CPU Idle calls when Linux is idle (unless this
1662 feature is turned off -- see "Do CPU IDLE calls", below). This
1663 should always save battery power, but more complicated APM features
1664 will be dependent on your BIOS implementation. You may need to turn
1665 this option off if your computer hangs at boot time when using APM
1666 support, or if it beeps continuously instead of suspending. Turn
1667 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1668 T400CDT. This is off by default since most machines do fine without
1672 bool "Make CPU Idle calls when idle"
1674 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1675 On some machines, this can activate improved power savings, such as
1676 a slowed CPU clock rate, when the machine is idle. These idle calls
1677 are made after the idle loop has run for some length of time (e.g.,
1678 333 mS). On some machines, this will cause a hang at boot time or
1679 whenever the CPU becomes idle. (On machines with more than one CPU,
1680 this option does nothing.)
1682 config APM_DISPLAY_BLANK
1683 bool "Enable console blanking using APM"
1685 Enable console blanking using the APM. Some laptops can use this to
1686 turn off the LCD backlight when the screen blanker of the Linux
1687 virtual console blanks the screen. Note that this is only used by
1688 the virtual console screen blanker, and won't turn off the backlight
1689 when using the X Window system. This also doesn't have anything to
1690 do with your VESA-compliant power-saving monitor. Further, this
1691 option doesn't work for all laptops -- it might not turn off your
1692 backlight at all, or it might print a lot of errors to the console,
1693 especially if you are using gpm.
1695 config APM_ALLOW_INTS
1696 bool "Allow interrupts during APM BIOS calls"
1698 Normally we disable external interrupts while we are making calls to
1699 the APM BIOS as a measure to lessen the effects of a badly behaving
1700 BIOS implementation. The BIOS should reenable interrupts if it
1701 needs to. Unfortunately, some BIOSes do not -- especially those in
1702 many of the newer IBM Thinkpads. If you experience hangs when you
1703 suspend, try setting this to Y. Otherwise, say N.
1707 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1709 source "drivers/cpuidle/Kconfig"
1711 source "drivers/idle/Kconfig"
1716 menu "Bus options (PCI etc.)"
1721 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1723 Find out whether you have a PCI motherboard. PCI is the name of a
1724 bus system, i.e. the way the CPU talks to the other stuff inside
1725 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1726 VESA. If you have PCI, say Y, otherwise N.
1729 prompt "PCI access mode"
1730 depends on X86_32 && PCI
1733 On PCI systems, the BIOS can be used to detect the PCI devices and
1734 determine their configuration. However, some old PCI motherboards
1735 have BIOS bugs and may crash if this is done. Also, some embedded
1736 PCI-based systems don't have any BIOS at all. Linux can also try to
1737 detect the PCI hardware directly without using the BIOS.
1739 With this option, you can specify how Linux should detect the
1740 PCI devices. If you choose "BIOS", the BIOS will be used,
1741 if you choose "Direct", the BIOS won't be used, and if you
1742 choose "MMConfig", then PCI Express MMCONFIG will be used.
1743 If you choose "Any", the kernel will try MMCONFIG, then the
1744 direct access method and falls back to the BIOS if that doesn't
1745 work. If unsure, go with the default, which is "Any".
1750 config PCI_GOMMCONFIG
1767 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1769 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1772 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1776 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1780 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1787 bool "Support mmconfig PCI config space access"
1788 depends on X86_64 && PCI && ACPI
1791 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1792 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1794 DMA remapping (DMAR) devices support enables independent address
1795 translations for Direct Memory Access (DMA) from devices.
1796 These DMA remapping devices are reported via ACPI tables
1797 and include PCI device scope covered by these DMA
1802 prompt "Support for Graphics workaround"
1805 Current Graphics drivers tend to use physical address
1806 for DMA and avoid using DMA APIs. Setting this config
1807 option permits the IOMMU driver to set a unity map for
1808 all the OS-visible memory. Hence the driver can continue
1809 to use physical addresses for DMA.
1811 config DMAR_FLOPPY_WA
1815 Floppy disk drivers are know to bypass DMA API calls
1816 thereby failing to work when IOMMU is enabled. This
1817 workaround will setup a 1:1 mapping for the first
1818 16M to make floppy (an ISA device) work.
1821 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1822 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1824 Supports Interrupt remapping for IO-APIC and MSI devices.
1825 To use x2apic mode in the CPU's which support x2APIC enhancements or
1826 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1828 source "drivers/pci/pcie/Kconfig"
1830 source "drivers/pci/Kconfig"
1832 # x86_64 have no ISA slots, but do have ISA-style DMA.
1841 Find out whether you have ISA slots on your motherboard. ISA is the
1842 name of a bus system, i.e. the way the CPU talks to the other stuff
1843 inside your box. Other bus systems are PCI, EISA, MicroChannel
1844 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1845 newer boards don't support it. If you have ISA, say Y, otherwise N.
1851 The Extended Industry Standard Architecture (EISA) bus was
1852 developed as an open alternative to the IBM MicroChannel bus.
1854 The EISA bus provided some of the features of the IBM MicroChannel
1855 bus while maintaining backward compatibility with cards made for
1856 the older ISA bus. The EISA bus saw limited use between 1988 and
1857 1995 when it was made obsolete by the PCI bus.
1859 Say Y here if you are building a kernel for an EISA-based machine.
1863 source "drivers/eisa/Kconfig"
1868 MicroChannel Architecture is found in some IBM PS/2 machines and
1869 laptops. It is a bus system similar to PCI or ISA. See
1870 <file:Documentation/mca.txt> (and especially the web page given
1871 there) before attempting to build an MCA bus kernel.
1873 source "drivers/mca/Kconfig"
1876 tristate "NatSemi SCx200 support"
1878 This provides basic support for National Semiconductor's
1879 (now AMD's) Geode processors. The driver probes for the
1880 PCI-IDs of several on-chip devices, so its a good dependency
1881 for other scx200_* drivers.
1883 If compiled as a module, the driver is named scx200.
1885 config SCx200HR_TIMER
1886 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1887 depends on SCx200 && GENERIC_TIME
1890 This driver provides a clocksource built upon the on-chip
1891 27MHz high-resolution timer. Its also a workaround for
1892 NSC Geode SC-1100's buggy TSC, which loses time when the
1893 processor goes idle (as is done by the scheduler). The
1894 other workaround is idle=poll boot option.
1896 config GEODE_MFGPT_TIMER
1898 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1899 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1901 This driver provides a clock event source based on the MFGPT
1902 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1903 MFGPTs have a better resolution and max interval than the
1904 generic PIT, and are suitable for use as high-res timers.
1907 bool "One Laptop Per Child support"
1910 Add support for detecting the unique features of the OLPC
1917 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1919 source "drivers/pcmcia/Kconfig"
1921 source "drivers/pci/hotplug/Kconfig"
1926 menu "Executable file formats / Emulations"
1928 source "fs/Kconfig.binfmt"
1930 config IA32_EMULATION
1931 bool "IA32 Emulation"
1933 select COMPAT_BINFMT_ELF
1935 Include code to run 32-bit programs under a 64-bit kernel. You should
1936 likely turn this on, unless you're 100% sure that you don't have any
1937 32-bit programs left.
1940 tristate "IA32 a.out support"
1941 depends on IA32_EMULATION
1943 Support old a.out binaries in the 32bit emulation.
1947 depends on IA32_EMULATION
1949 config COMPAT_FOR_U64_ALIGNMENT
1953 config SYSVIPC_COMPAT
1955 depends on COMPAT && SYSVIPC
1960 config HAVE_ATOMIC_IOMAP
1964 source "net/Kconfig"
1966 source "drivers/Kconfig"
1968 source "drivers/firmware/Kconfig"
1972 source "arch/x86/Kconfig.debug"
1974 source "security/Kconfig"
1976 source "crypto/Kconfig"
1978 source "arch/x86/kvm/Kconfig"
1980 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob