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.
278 Select this for an AMD Elan processor.
280 Do not use this option for K6/Athlon/Opteron processors!
282 If unsure, choose "PC-compatible" instead.
286 depends on X86_32 && SMP && !PCI && BROKEN
288 Voyager is an MCA-based 32-way capable SMP architecture proprietary
289 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
293 If you do not specifically know you have a Voyager based machine,
294 say N here, otherwise the kernel you build will not be bootable.
296 config X86_GENERICARCH
297 bool "Generic architecture"
300 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
301 subarchitectures. It is intended for a generic binary kernel.
302 if you select them all, kernel will probe it one by one. and will
308 bool "NUMAQ (IBM/Sequent)"
309 depends on SMP && X86_32 && PCI && X86_MPPARSE
312 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
313 NUMA multiquad box. This changes the way that processors are
314 bootstrapped, and uses Clustered Logical APIC addressing mode instead
315 of Flat Logical. You will need a new lynxer.elf file to flash your
316 firmware with - send email to <Martin.Bligh@us.ibm.com>.
319 bool "Summit/EXA (IBM x440)"
320 depends on X86_32 && SMP
322 This option is needed for IBM systems that use the Summit/EXA chipset.
323 In particular, it is needed for the x440.
326 bool "Support for Unisys ES7000 IA32 series"
327 depends on X86_32 && SMP
329 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
330 supposed to run on an IA32-based Unisys ES7000 system.
333 bool "Support for big SMP systems with more than 8 CPUs"
334 depends on X86_32 && SMP
336 This option is needed for the systems that have more than 8 CPUs
337 and if the system is not of any sub-arch type above.
342 bool "Support for ScaleMP vSMP"
344 depends on X86_64 && PCI
346 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
347 supposed to run on these EM64T-based machines. Only choose this option
348 if you have one of these machines.
352 config X86_NON_STANDARD
353 bool "Support for non-standard x86 platforms"
355 If you disable this option then the kernel will only support
356 standard PC platforms. (which covers the vast majority of
359 If you enable this option then you'll be able to select a number
360 of less common non-PC x86 platforms: VisWS, RDC321, SGI/UV.
362 If you have one of these systems, or if you want to build a
363 generic distribution kernel, say Y here - otherwise say N.
366 bool "SGI 320/540 (Visual Workstation)"
367 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
368 depends on X86_NON_STANDARD
370 The SGI Visual Workstation series is an IA32-based workstation
371 based on SGI systems chips with some legacy PC hardware attached.
373 Say Y here to create a kernel to run on the SGI 320 or 540.
375 A kernel compiled for the Visual Workstation will run on general
376 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
379 bool "RDC R-321x SoC"
381 depends on X86_NON_STANDARD
383 select X86_REBOOTFIXUPS
385 This option is needed for RDC R-321x system-on-chip, also known
387 If you don't have one of these chips, you should say N here.
390 bool "SGI Ultraviolet"
392 depends on X86_NON_STANDARD
394 This option is needed in order to support SGI Ultraviolet systems.
395 If you don't have one of these, you should say N here.
397 config SCHED_OMIT_FRAME_POINTER
399 prompt "Single-depth WCHAN output"
402 Calculate simpler /proc/<PID>/wchan values. If this option
403 is disabled then wchan values will recurse back to the
404 caller function. This provides more accurate wchan values,
405 at the expense of slightly more scheduling overhead.
407 If in doubt, say "Y".
409 menuconfig PARAVIRT_GUEST
410 bool "Paravirtualized guest support"
412 Say Y here to get to see options related to running Linux under
413 various hypervisors. This option alone does not add any kernel code.
415 If you say N, all options in this submenu will be skipped and disabled.
419 source "arch/x86/xen/Kconfig"
422 bool "VMI Guest support"
426 VMI provides a paravirtualized interface to the VMware ESX server
427 (it could be used by other hypervisors in theory too, but is not
428 at the moment), by linking the kernel to a GPL-ed ROM module
429 provided by the hypervisor.
432 bool "KVM paravirtualized clock"
434 select PARAVIRT_CLOCK
436 Turning on this option will allow you to run a paravirtualized clock
437 when running over the KVM hypervisor. Instead of relying on a PIT
438 (or probably other) emulation by the underlying device model, the host
439 provides the guest with timing infrastructure such as time of day, and
443 bool "KVM Guest support"
446 This option enables various optimizations for running under the KVM
449 source "arch/x86/lguest/Kconfig"
452 bool "Enable paravirtualization code"
454 This changes the kernel so it can modify itself when it is run
455 under a hypervisor, potentially improving performance significantly
456 over full virtualization. However, when run without a hypervisor
457 the kernel is theoretically slower and slightly larger.
459 config PARAVIRT_CLOCK
465 config PARAVIRT_DEBUG
466 bool "paravirt-ops debugging"
467 depends on PARAVIRT && DEBUG_KERNEL
469 Enable to debug paravirt_ops internals. Specifically, BUG if
470 a paravirt_op is missing when it is called.
475 This option adds a kernel parameter 'memtest', which allows memtest
477 memtest=0, mean disabled; -- default
478 memtest=1, mean do 1 test pattern;
480 memtest=4, mean do 4 test patterns.
481 If you are unsure how to answer this question, answer N.
483 config X86_SUMMIT_NUMA
485 depends on X86_32 && NUMA && X86_GENERICARCH
487 config X86_CYCLONE_TIMER
489 depends on X86_GENERICARCH
491 source "arch/x86/Kconfig.cpu"
495 prompt "HPET Timer Support" if X86_32
497 Use the IA-PC HPET (High Precision Event Timer) to manage
498 time in preference to the PIT and RTC, if a HPET is
500 HPET is the next generation timer replacing legacy 8254s.
501 The HPET provides a stable time base on SMP
502 systems, unlike the TSC, but it is more expensive to access,
503 as it is off-chip. You can find the HPET spec at
504 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
506 You can safely choose Y here. However, HPET will only be
507 activated if the platform and the BIOS support this feature.
508 Otherwise the 8254 will be used for timing services.
510 Choose N to continue using the legacy 8254 timer.
512 config HPET_EMULATE_RTC
514 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
516 # Mark as embedded because too many people got it wrong.
517 # The code disables itself when not needed.
520 bool "Enable DMI scanning" if EMBEDDED
522 Enabled scanning of DMI to identify machine quirks. Say Y
523 here unless you have verified that your setup is not
524 affected by entries in the DMI blacklist. Required by PNP
528 bool "GART IOMMU support" if EMBEDDED
532 depends on X86_64 && PCI
534 Support for full DMA access of devices with 32bit memory access only
535 on systems with more than 3GB. This is usually needed for USB,
536 sound, many IDE/SATA chipsets and some other devices.
537 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
538 based hardware IOMMU and a software bounce buffer based IOMMU used
539 on Intel systems and as fallback.
540 The code is only active when needed (enough memory and limited
541 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
545 bool "IBM Calgary IOMMU support"
547 depends on X86_64 && PCI && EXPERIMENTAL
549 Support for hardware IOMMUs in IBM's xSeries x366 and x460
550 systems. Needed to run systems with more than 3GB of memory
551 properly with 32-bit PCI devices that do not support DAC
552 (Double Address Cycle). Calgary also supports bus level
553 isolation, where all DMAs pass through the IOMMU. This
554 prevents them from going anywhere except their intended
555 destination. This catches hard-to-find kernel bugs and
556 mis-behaving drivers and devices that do not use the DMA-API
557 properly to set up their DMA buffers. The IOMMU can be
558 turned off at boot time with the iommu=off parameter.
559 Normally the kernel will make the right choice by itself.
562 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
564 prompt "Should Calgary be enabled by default?"
565 depends on CALGARY_IOMMU
567 Should Calgary be enabled by default? if you choose 'y', Calgary
568 will be used (if it exists). If you choose 'n', Calgary will not be
569 used even if it exists. If you choose 'n' and would like to use
570 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
574 bool "AMD IOMMU support"
577 depends on X86_64 && PCI && ACPI
579 With this option you can enable support for AMD IOMMU hardware in
580 your system. An IOMMU is a hardware component which provides
581 remapping of DMA memory accesses from devices. With an AMD IOMMU you
582 can isolate the the DMA memory of different devices and protect the
583 system from misbehaving device drivers or hardware.
585 You can find out if your system has an AMD IOMMU if you look into
586 your BIOS for an option to enable it or if you have an IVRS ACPI
589 config AMD_IOMMU_STATS
590 bool "Export AMD IOMMU statistics to debugfs"
594 This option enables code in the AMD IOMMU driver to collect various
595 statistics about whats happening in the driver and exports that
596 information to userspace via debugfs.
599 # need this always selected by IOMMU for the VIA workaround
603 Support for software bounce buffers used on x86-64 systems
604 which don't have a hardware IOMMU (e.g. the current generation
605 of Intel's x86-64 CPUs). Using this PCI devices which can only
606 access 32-bits of memory can be used on systems with more than
607 3 GB of memory. If unsure, say Y.
610 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
613 def_bool (AMD_IOMMU || DMAR)
616 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
617 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
618 select CPUMASK_OFFSTACK
621 Configure maximum number of CPUS and NUMA Nodes for this architecture.
625 int "Maximum number of CPUs" if SMP && !MAXSMP
626 range 2 512 if SMP && !MAXSMP
628 default "4096" if MAXSMP
629 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
632 This allows you to specify the maximum number of CPUs which this
633 kernel will support. The maximum supported value is 512 and the
634 minimum value which makes sense is 2.
636 This is purely to save memory - each supported CPU adds
637 approximately eight kilobytes to the kernel image.
640 bool "SMT (Hyperthreading) scheduler support"
643 SMT scheduler support improves the CPU scheduler's decision making
644 when dealing with Intel Pentium 4 chips with HyperThreading at a
645 cost of slightly increased overhead in some places. If unsure say
650 prompt "Multi-core scheduler support"
653 Multi-core scheduler support improves the CPU scheduler's decision
654 making when dealing with multi-core CPU chips at a cost of slightly
655 increased overhead in some places. If unsure say N here.
657 source "kernel/Kconfig.preempt"
660 bool "Local APIC support on uniprocessors"
661 depends on X86_32 && !SMP && !X86_GENERICARCH
663 A local APIC (Advanced Programmable Interrupt Controller) is an
664 integrated interrupt controller in the CPU. If you have a single-CPU
665 system which has a processor with a local APIC, you can say Y here to
666 enable and use it. If you say Y here even though your machine doesn't
667 have a local APIC, then the kernel will still run with no slowdown at
668 all. The local APIC supports CPU-generated self-interrupts (timer,
669 performance counters), and the NMI watchdog which detects hard
673 bool "IO-APIC support on uniprocessors"
674 depends on X86_UP_APIC
676 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
677 SMP-capable replacement for PC-style interrupt controllers. Most
678 SMP systems and many recent uniprocessor systems have one.
680 If you have a single-CPU system with an IO-APIC, you can say Y here
681 to use it. If you say Y here even though your machine doesn't have
682 an IO-APIC, then the kernel will still run with no slowdown at all.
684 config X86_LOCAL_APIC
686 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
690 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
692 config X86_VISWS_APIC
694 depends on X86_32 && X86_VISWS
696 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
697 bool "Reroute for broken boot IRQs"
699 depends on X86_IO_APIC
701 This option enables a workaround that fixes a source of
702 spurious interrupts. This is recommended when threaded
703 interrupt handling is used on systems where the generation of
704 superfluous "boot interrupts" cannot be disabled.
706 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
707 entry in the chipset's IO-APIC is masked (as, e.g. the RT
708 kernel does during interrupt handling). On chipsets where this
709 boot IRQ generation cannot be disabled, this workaround keeps
710 the original IRQ line masked so that only the equivalent "boot
711 IRQ" is delivered to the CPUs. The workaround also tells the
712 kernel to set up the IRQ handler on the boot IRQ line. In this
713 way only one interrupt is delivered to the kernel. Otherwise
714 the spurious second interrupt may cause the kernel to bring
715 down (vital) interrupt lines.
717 Only affects "broken" chipsets. Interrupt sharing may be
718 increased on these systems.
721 bool "Machine Check Exception"
723 Machine Check Exception support allows the processor to notify the
724 kernel if it detects a problem (e.g. overheating, component failure).
725 The action the kernel takes depends on the severity of the problem,
726 ranging from a warning message on the console, to halting the machine.
727 Your processor must be a Pentium or newer to support this - check the
728 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
729 have a design flaw which leads to false MCE events - hence MCE is
730 disabled on all P5 processors, unless explicitly enabled with "mce"
731 as a boot argument. Similarly, if MCE is built in and creates a
732 problem on some new non-standard machine, you can boot with "nomce"
733 to disable it. MCE support simply ignores non-MCE processors like
734 the 386 and 486, so nearly everyone can say Y here.
738 prompt "Intel MCE features"
739 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
741 Additional support for intel specific MCE features such as
746 prompt "AMD MCE features"
747 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
749 Additional support for AMD specific MCE features such as
750 the DRAM Error Threshold.
752 config X86_MCE_NONFATAL
753 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
754 depends on X86_32 && X86_MCE
756 Enabling this feature starts a timer that triggers every 5 seconds which
757 will look at the machine check registers to see if anything happened.
758 Non-fatal problems automatically get corrected (but still logged).
759 Disable this if you don't want to see these messages.
760 Seeing the messages this option prints out may be indicative of dying
761 or out-of-spec (ie, overclocked) hardware.
762 This option only does something on certain CPUs.
763 (AMD Athlon/Duron and Intel Pentium 4)
765 config X86_MCE_P4THERMAL
766 bool "check for P4 thermal throttling interrupt."
767 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
769 Enabling this feature will cause a message to be printed when the P4
770 enters thermal throttling.
773 bool "Enable VM86 support" if EMBEDDED
777 This option is required by programs like DOSEMU to run 16-bit legacy
778 code on X86 processors. It also may be needed by software like
779 XFree86 to initialize some video cards via BIOS. Disabling this
780 option saves about 6k.
783 tristate "Toshiba Laptop support"
786 This adds a driver to safely access the System Management Mode of
787 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
788 not work on models with a Phoenix BIOS. The System Management Mode
789 is used to set the BIOS and power saving options on Toshiba portables.
791 For information on utilities to make use of this driver see the
792 Toshiba Linux utilities web site at:
793 <http://www.buzzard.org.uk/toshiba/>.
795 Say Y if you intend to run this kernel on a Toshiba portable.
799 tristate "Dell laptop support"
801 This adds a driver to safely access the System Management Mode
802 of the CPU on the Dell Inspiron 8000. The System Management Mode
803 is used to read cpu temperature and cooling fan status and to
804 control the fans on the I8K portables.
806 This driver has been tested only on the Inspiron 8000 but it may
807 also work with other Dell laptops. You can force loading on other
808 models by passing the parameter `force=1' to the module. Use at
811 For information on utilities to make use of this driver see the
812 I8K Linux utilities web site at:
813 <http://people.debian.org/~dz/i8k/>
815 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
818 config X86_REBOOTFIXUPS
819 bool "Enable X86 board specific fixups for reboot"
822 This enables chipset and/or board specific fixups to be done
823 in order to get reboot to work correctly. This is only needed on
824 some combinations of hardware and BIOS. The symptom, for which
825 this config is intended, is when reboot ends with a stalled/hung
828 Currently, the only fixup is for the Geode machines using
829 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
831 Say Y if you want to enable the fixup. Currently, it's safe to
832 enable this option even if you don't need it.
836 tristate "/dev/cpu/microcode - microcode support"
839 If you say Y here, you will be able to update the microcode on
840 certain Intel and AMD processors. The Intel support is for the
841 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
842 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
843 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
844 You will obviously need the actual microcode binary data itself
845 which is not shipped with the Linux kernel.
847 This option selects the general module only, you need to select
848 at least one vendor specific module as well.
850 To compile this driver as a module, choose M here: the
851 module will be called microcode.
853 config MICROCODE_INTEL
854 bool "Intel microcode patch loading support"
859 This options enables microcode patch loading support for Intel
862 For latest news and information on obtaining all the required
863 Intel ingredients for this driver, check:
864 <http://www.urbanmyth.org/microcode/>.
867 bool "AMD microcode patch loading support"
871 If you select this option, microcode patch loading support for AMD
872 processors will be enabled.
874 config MICROCODE_OLD_INTERFACE
879 tristate "/dev/cpu/*/msr - Model-specific register support"
881 This device gives privileged processes access to the x86
882 Model-Specific Registers (MSRs). It is a character device with
883 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
884 MSR accesses are directed to a specific CPU on multi-processor
888 tristate "/dev/cpu/*/cpuid - CPU information support"
890 This device gives processes access to the x86 CPUID instruction to
891 be executed on a specific processor. It is a character device
892 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
896 prompt "High Memory Support"
897 default HIGHMEM4G if !X86_NUMAQ
898 default HIGHMEM64G if X86_NUMAQ
903 depends on !X86_NUMAQ
905 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
906 However, the address space of 32-bit x86 processors is only 4
907 Gigabytes large. That means that, if you have a large amount of
908 physical memory, not all of it can be "permanently mapped" by the
909 kernel. The physical memory that's not permanently mapped is called
912 If you are compiling a kernel which will never run on a machine with
913 more than 1 Gigabyte total physical RAM, answer "off" here (default
914 choice and suitable for most users). This will result in a "3GB/1GB"
915 split: 3GB are mapped so that each process sees a 3GB virtual memory
916 space and the remaining part of the 4GB virtual memory space is used
917 by the kernel to permanently map as much physical memory as
920 If the machine has between 1 and 4 Gigabytes physical RAM, then
923 If more than 4 Gigabytes is used then answer "64GB" here. This
924 selection turns Intel PAE (Physical Address Extension) mode on.
925 PAE implements 3-level paging on IA32 processors. PAE is fully
926 supported by Linux, PAE mode is implemented on all recent Intel
927 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
928 then the kernel will not boot on CPUs that don't support PAE!
930 The actual amount of total physical memory will either be
931 auto detected or can be forced by using a kernel command line option
932 such as "mem=256M". (Try "man bootparam" or see the documentation of
933 your boot loader (lilo or loadlin) about how to pass options to the
934 kernel at boot time.)
936 If unsure, say "off".
940 depends on !X86_NUMAQ
942 Select this if you have a 32-bit processor and between 1 and 4
943 gigabytes of physical RAM.
947 depends on !M386 && !M486
950 Select this if you have a 32-bit processor and more than 4
951 gigabytes of physical RAM.
956 depends on EXPERIMENTAL
957 prompt "Memory split" if EMBEDDED
961 Select the desired split between kernel and user memory.
963 If the address range available to the kernel is less than the
964 physical memory installed, the remaining memory will be available
965 as "high memory". Accessing high memory is a little more costly
966 than low memory, as it needs to be mapped into the kernel first.
967 Note that increasing the kernel address space limits the range
968 available to user programs, making the address space there
969 tighter. Selecting anything other than the default 3G/1G split
970 will also likely make your kernel incompatible with binary-only
973 If you are not absolutely sure what you are doing, leave this
977 bool "3G/1G user/kernel split"
978 config VMSPLIT_3G_OPT
980 bool "3G/1G user/kernel split (for full 1G low memory)"
982 bool "2G/2G user/kernel split"
983 config VMSPLIT_2G_OPT
985 bool "2G/2G user/kernel split (for full 2G low memory)"
987 bool "1G/3G user/kernel split"
992 default 0xB0000000 if VMSPLIT_3G_OPT
993 default 0x80000000 if VMSPLIT_2G
994 default 0x78000000 if VMSPLIT_2G_OPT
995 default 0x40000000 if VMSPLIT_1G
1001 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1004 bool "PAE (Physical Address Extension) Support"
1005 depends on X86_32 && !HIGHMEM4G
1007 PAE is required for NX support, and furthermore enables
1008 larger swapspace support for non-overcommit purposes. It
1009 has the cost of more pagetable lookup overhead, and also
1010 consumes more pagetable space per process.
1012 config ARCH_PHYS_ADDR_T_64BIT
1013 def_bool X86_64 || X86_PAE
1015 config DIRECT_GBPAGES
1016 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1020 Allow the kernel linear mapping to use 1GB pages on CPUs that
1021 support it. This can improve the kernel's performance a tiny bit by
1022 reducing TLB pressure. If in doubt, say "Y".
1024 # Common NUMA Features
1026 bool "Numa Memory Allocation and Scheduler Support"
1028 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1030 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1032 Enable NUMA (Non Uniform Memory Access) support.
1034 The kernel will try to allocate memory used by a CPU on the
1035 local memory controller of the CPU and add some more
1036 NUMA awareness to the kernel.
1038 For 64-bit this is recommended if the system is Intel Core i7
1039 (or later), AMD Opteron, or EM64T NUMA.
1041 For 32-bit this is only needed on (rare) 32-bit-only platforms
1042 that support NUMA topologies, such as NUMAQ / Summit, or if you
1043 boot a 32-bit kernel on a 64-bit NUMA platform.
1045 Otherwise, you should say N.
1047 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1048 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1052 prompt "Old style AMD Opteron NUMA detection"
1053 depends on X86_64 && NUMA && PCI
1055 Enable K8 NUMA node topology detection. You should say Y here if
1056 you have a multi processor AMD K8 system. This uses an old
1057 method to read the NUMA configuration directly from the builtin
1058 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1059 instead, which also takes priority if both are compiled in.
1061 config X86_64_ACPI_NUMA
1063 prompt "ACPI NUMA detection"
1064 depends on X86_64 && NUMA && ACPI && PCI
1067 Enable ACPI SRAT based node topology detection.
1069 # Some NUMA nodes have memory ranges that span
1070 # other nodes. Even though a pfn is valid and
1071 # between a node's start and end pfns, it may not
1072 # reside on that node. See memmap_init_zone()
1074 config NODES_SPAN_OTHER_NODES
1076 depends on X86_64_ACPI_NUMA
1079 bool "NUMA emulation"
1080 depends on X86_64 && NUMA
1082 Enable NUMA emulation. A flat machine will be split
1083 into virtual nodes when booted with "numa=fake=N", where N is the
1084 number of nodes. This is only useful for debugging.
1087 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1089 default "9" if MAXSMP
1090 default "6" if X86_64
1091 default "4" if X86_NUMAQ
1093 depends on NEED_MULTIPLE_NODES
1095 Specify the maximum number of NUMA Nodes available on the target
1096 system. Increases memory reserved to accomodate various tables.
1098 config HAVE_ARCH_BOOTMEM_NODE
1100 depends on X86_32 && NUMA
1102 config ARCH_HAVE_MEMORY_PRESENT
1104 depends on X86_32 && DISCONTIGMEM
1106 config NEED_NODE_MEMMAP_SIZE
1108 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1110 config HAVE_ARCH_ALLOC_REMAP
1112 depends on X86_32 && NUMA
1114 config ARCH_FLATMEM_ENABLE
1116 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1118 config ARCH_DISCONTIGMEM_ENABLE
1120 depends on NUMA && X86_32
1122 config ARCH_DISCONTIGMEM_DEFAULT
1124 depends on NUMA && X86_32
1126 config ARCH_SPARSEMEM_DEFAULT
1130 config ARCH_SPARSEMEM_ENABLE
1132 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1133 select SPARSEMEM_STATIC if X86_32
1134 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1136 config ARCH_SELECT_MEMORY_MODEL
1138 depends on ARCH_SPARSEMEM_ENABLE
1140 config ARCH_MEMORY_PROBE
1142 depends on MEMORY_HOTPLUG
1147 bool "Allocate 3rd-level pagetables from highmem"
1148 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1150 The VM uses one page table entry for each page of physical memory.
1151 For systems with a lot of RAM, this can be wasteful of precious
1152 low memory. Setting this option will put user-space page table
1153 entries in high memory.
1155 config X86_CHECK_BIOS_CORRUPTION
1156 bool "Check for low memory corruption"
1158 Periodically check for memory corruption in low memory, which
1159 is suspected to be caused by BIOS. Even when enabled in the
1160 configuration, it is disabled at runtime. Enable it by
1161 setting "memory_corruption_check=1" on the kernel command
1162 line. By default it scans the low 64k of memory every 60
1163 seconds; see the memory_corruption_check_size and
1164 memory_corruption_check_period parameters in
1165 Documentation/kernel-parameters.txt to adjust this.
1167 When enabled with the default parameters, this option has
1168 almost no overhead, as it reserves a relatively small amount
1169 of memory and scans it infrequently. It both detects corruption
1170 and prevents it from affecting the running system.
1172 It is, however, intended as a diagnostic tool; if repeatable
1173 BIOS-originated corruption always affects the same memory,
1174 you can use memmap= to prevent the kernel from using that
1177 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1178 bool "Set the default setting of memory_corruption_check"
1179 depends on X86_CHECK_BIOS_CORRUPTION
1182 Set whether the default state of memory_corruption_check is
1185 config X86_RESERVE_LOW_64K
1186 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1189 Reserve the first 64K of physical RAM on BIOSes that are known
1190 to potentially corrupt that memory range. A numbers of BIOSes are
1191 known to utilize this area during suspend/resume, so it must not
1192 be used by the kernel.
1194 Set this to N if you are absolutely sure that you trust the BIOS
1195 to get all its memory reservations and usages right.
1197 If you have doubts about the BIOS (e.g. suspend/resume does not
1198 work or there's kernel crashes after certain hardware hotplug
1199 events) and it's not AMI or Phoenix, then you might want to enable
1200 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1201 corruption patterns.
1205 config MATH_EMULATION
1207 prompt "Math emulation" if X86_32
1209 Linux can emulate a math coprocessor (used for floating point
1210 operations) if you don't have one. 486DX and Pentium processors have
1211 a math coprocessor built in, 486SX and 386 do not, unless you added
1212 a 487DX or 387, respectively. (The messages during boot time can
1213 give you some hints here ["man dmesg"].) Everyone needs either a
1214 coprocessor or this emulation.
1216 If you don't have a math coprocessor, you need to say Y here; if you
1217 say Y here even though you have a coprocessor, the coprocessor will
1218 be used nevertheless. (This behavior can be changed with the kernel
1219 command line option "no387", which comes handy if your coprocessor
1220 is broken. Try "man bootparam" or see the documentation of your boot
1221 loader (lilo or loadlin) about how to pass options to the kernel at
1222 boot time.) This means that it is a good idea to say Y here if you
1223 intend to use this kernel on different machines.
1225 More information about the internals of the Linux math coprocessor
1226 emulation can be found in <file:arch/x86/math-emu/README>.
1228 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1229 kernel, it won't hurt.
1232 bool "MTRR (Memory Type Range Register) support"
1234 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1235 the Memory Type Range Registers (MTRRs) may be used to control
1236 processor access to memory ranges. This is most useful if you have
1237 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1238 allows bus write transfers to be combined into a larger transfer
1239 before bursting over the PCI/AGP bus. This can increase performance
1240 of image write operations 2.5 times or more. Saying Y here creates a
1241 /proc/mtrr file which may be used to manipulate your processor's
1242 MTRRs. Typically the X server should use this.
1244 This code has a reasonably generic interface so that similar
1245 control registers on other processors can be easily supported
1248 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1249 Registers (ARRs) which provide a similar functionality to MTRRs. For
1250 these, the ARRs are used to emulate the MTRRs.
1251 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1252 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1253 write-combining. All of these processors are supported by this code
1254 and it makes sense to say Y here if you have one of them.
1256 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1257 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1258 can lead to all sorts of problems, so it's good to say Y here.
1260 You can safely say Y even if your machine doesn't have MTRRs, you'll
1261 just add about 9 KB to your kernel.
1263 See <file:Documentation/x86/mtrr.txt> for more information.
1265 config MTRR_SANITIZER
1267 prompt "MTRR cleanup support"
1270 Convert MTRR layout from continuous to discrete, so X drivers can
1271 add writeback entries.
1273 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1274 The largest mtrr entry size for a continous block can be set with
1279 config MTRR_SANITIZER_ENABLE_DEFAULT
1280 int "MTRR cleanup enable value (0-1)"
1283 depends on MTRR_SANITIZER
1285 Enable mtrr cleanup default value
1287 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1288 int "MTRR cleanup spare reg num (0-7)"
1291 depends on MTRR_SANITIZER
1293 mtrr cleanup spare entries default, it can be changed via
1294 mtrr_spare_reg_nr=N on the kernel command line.
1298 prompt "x86 PAT support"
1301 Use PAT attributes to setup page level cache control.
1303 PATs are the modern equivalents of MTRRs and are much more
1304 flexible than MTRRs.
1306 Say N here if you see bootup problems (boot crash, boot hang,
1307 spontaneous reboots) or a non-working video driver.
1312 bool "EFI runtime service support"
1315 This enables the kernel to use EFI runtime services that are
1316 available (such as the EFI variable services).
1318 This option is only useful on systems that have EFI firmware.
1319 In addition, you should use the latest ELILO loader available
1320 at <http://elilo.sourceforge.net> in order to take advantage
1321 of EFI runtime services. However, even with this option, the
1322 resultant kernel should continue to boot on existing non-EFI
1327 prompt "Enable seccomp to safely compute untrusted bytecode"
1329 This kernel feature is useful for number crunching applications
1330 that may need to compute untrusted bytecode during their
1331 execution. By using pipes or other transports made available to
1332 the process as file descriptors supporting the read/write
1333 syscalls, it's possible to isolate those applications in
1334 their own address space using seccomp. Once seccomp is
1335 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1336 and the task is only allowed to execute a few safe syscalls
1337 defined by each seccomp mode.
1339 If unsure, say Y. Only embedded should say N here.
1341 config CC_STACKPROTECTOR_ALL
1344 config CC_STACKPROTECTOR
1345 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1347 select CC_STACKPROTECTOR_ALL
1349 This option turns on the -fstack-protector GCC feature. This
1350 feature puts, at the beginning of functions, a canary value on
1351 the stack just before the return address, and validates
1352 the value just before actually returning. Stack based buffer
1353 overflows (that need to overwrite this return address) now also
1354 overwrite the canary, which gets detected and the attack is then
1355 neutralized via a kernel panic.
1357 This feature requires gcc version 4.2 or above, or a distribution
1358 gcc with the feature backported. Older versions are automatically
1359 detected and for those versions, this configuration option is
1360 ignored. (and a warning is printed during bootup)
1362 source kernel/Kconfig.hz
1365 bool "kexec system call"
1367 kexec is a system call that implements the ability to shutdown your
1368 current kernel, and to start another kernel. It is like a reboot
1369 but it is independent of the system firmware. And like a reboot
1370 you can start any kernel with it, not just Linux.
1372 The name comes from the similarity to the exec system call.
1374 It is an ongoing process to be certain the hardware in a machine
1375 is properly shutdown, so do not be surprised if this code does not
1376 initially work for you. It may help to enable device hotplugging
1377 support. As of this writing the exact hardware interface is
1378 strongly in flux, so no good recommendation can be made.
1381 bool "kernel crash dumps"
1382 depends on X86_64 || (X86_32 && HIGHMEM)
1384 Generate crash dump after being started by kexec.
1385 This should be normally only set in special crash dump kernels
1386 which are loaded in the main kernel with kexec-tools into
1387 a specially reserved region and then later executed after
1388 a crash by kdump/kexec. The crash dump kernel must be compiled
1389 to a memory address not used by the main kernel or BIOS using
1390 PHYSICAL_START, or it must be built as a relocatable image
1391 (CONFIG_RELOCATABLE=y).
1392 For more details see Documentation/kdump/kdump.txt
1395 bool "kexec jump (EXPERIMENTAL)"
1396 depends on EXPERIMENTAL
1397 depends on KEXEC && HIBERNATION && X86_32
1399 Jump between original kernel and kexeced kernel and invoke
1400 code in physical address mode via KEXEC
1402 config PHYSICAL_START
1403 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1404 default "0x1000000" if X86_NUMAQ
1405 default "0x200000" if X86_64
1408 This gives the physical address where the kernel is loaded.
1410 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1411 bzImage will decompress itself to above physical address and
1412 run from there. Otherwise, bzImage will run from the address where
1413 it has been loaded by the boot loader and will ignore above physical
1416 In normal kdump cases one does not have to set/change this option
1417 as now bzImage can be compiled as a completely relocatable image
1418 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1419 address. This option is mainly useful for the folks who don't want
1420 to use a bzImage for capturing the crash dump and want to use a
1421 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1422 to be specifically compiled to run from a specific memory area
1423 (normally a reserved region) and this option comes handy.
1425 So if you are using bzImage for capturing the crash dump, leave
1426 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1427 Otherwise if you plan to use vmlinux for capturing the crash dump
1428 change this value to start of the reserved region (Typically 16MB
1429 0x1000000). In other words, it can be set based on the "X" value as
1430 specified in the "crashkernel=YM@XM" command line boot parameter
1431 passed to the panic-ed kernel. Typically this parameter is set as
1432 crashkernel=64M@16M. Please take a look at
1433 Documentation/kdump/kdump.txt for more details about crash dumps.
1435 Usage of bzImage for capturing the crash dump is recommended as
1436 one does not have to build two kernels. Same kernel can be used
1437 as production kernel and capture kernel. Above option should have
1438 gone away after relocatable bzImage support is introduced. But it
1439 is present because there are users out there who continue to use
1440 vmlinux for dump capture. This option should go away down the
1443 Don't change this unless you know what you are doing.
1446 bool "Build a relocatable kernel (EXPERIMENTAL)"
1447 depends on EXPERIMENTAL
1449 This builds a kernel image that retains relocation information
1450 so it can be loaded someplace besides the default 1MB.
1451 The relocations tend to make the kernel binary about 10% larger,
1452 but are discarded at runtime.
1454 One use is for the kexec on panic case where the recovery kernel
1455 must live at a different physical address than the primary
1458 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1459 it has been loaded at and the compile time physical address
1460 (CONFIG_PHYSICAL_START) is ignored.
1462 config PHYSICAL_ALIGN
1464 prompt "Alignment value to which kernel should be aligned" if X86_32
1465 default "0x100000" if X86_32
1466 default "0x200000" if X86_64
1467 range 0x2000 0x400000
1469 This value puts the alignment restrictions on physical address
1470 where kernel is loaded and run from. Kernel is compiled for an
1471 address which meets above alignment restriction.
1473 If bootloader loads the kernel at a non-aligned address and
1474 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1475 address aligned to above value and run from there.
1477 If bootloader loads the kernel at a non-aligned address and
1478 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1479 load address and decompress itself to the address it has been
1480 compiled for and run from there. The address for which kernel is
1481 compiled already meets above alignment restrictions. Hence the
1482 end result is that kernel runs from a physical address meeting
1483 above alignment restrictions.
1485 Don't change this unless you know what you are doing.
1488 bool "Support for hot-pluggable CPUs"
1489 depends on SMP && HOTPLUG
1491 Say Y here to allow turning CPUs off and on. CPUs can be
1492 controlled through /sys/devices/system/cpu.
1493 ( Note: power management support will enable this option
1494 automatically on SMP systems. )
1495 Say N if you want to disable CPU hotplug.
1499 prompt "Compat VDSO support"
1500 depends on X86_32 || IA32_EMULATION
1502 Map the 32-bit VDSO to the predictable old-style address too.
1504 Say N here if you are running a sufficiently recent glibc
1505 version (2.3.3 or later), to remove the high-mapped
1506 VDSO mapping and to exclusively use the randomized VDSO.
1511 bool "Built-in kernel command line"
1514 Allow for specifying boot arguments to the kernel at
1515 build time. On some systems (e.g. embedded ones), it is
1516 necessary or convenient to provide some or all of the
1517 kernel boot arguments with the kernel itself (that is,
1518 to not rely on the boot loader to provide them.)
1520 To compile command line arguments into the kernel,
1521 set this option to 'Y', then fill in the
1522 the boot arguments in CONFIG_CMDLINE.
1524 Systems with fully functional boot loaders (i.e. non-embedded)
1525 should leave this option set to 'N'.
1528 string "Built-in kernel command string"
1529 depends on CMDLINE_BOOL
1532 Enter arguments here that should be compiled into the kernel
1533 image and used at boot time. If the boot loader provides a
1534 command line at boot time, it is appended to this string to
1535 form the full kernel command line, when the system boots.
1537 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1538 change this behavior.
1540 In most cases, the command line (whether built-in or provided
1541 by the boot loader) should specify the device for the root
1544 config CMDLINE_OVERRIDE
1545 bool "Built-in command line overrides boot loader arguments"
1547 depends on CMDLINE_BOOL
1549 Set this option to 'Y' to have the kernel ignore the boot loader
1550 command line, and use ONLY the built-in command line.
1552 This is used to work around broken boot loaders. This should
1553 be set to 'N' under normal conditions.
1557 config ARCH_ENABLE_MEMORY_HOTPLUG
1559 depends on X86_64 || (X86_32 && HIGHMEM)
1561 config ARCH_ENABLE_MEMORY_HOTREMOVE
1563 depends on MEMORY_HOTPLUG
1565 config HAVE_ARCH_EARLY_PFN_TO_NID
1569 menu "Power management and ACPI options"
1571 config ARCH_HIBERNATION_HEADER
1573 depends on X86_64 && HIBERNATION
1575 source "kernel/power/Kconfig"
1577 source "drivers/acpi/Kconfig"
1582 depends on APM || APM_MODULE
1585 tristate "APM (Advanced Power Management) BIOS support"
1586 depends on X86_32 && PM_SLEEP
1588 APM is a BIOS specification for saving power using several different
1589 techniques. This is mostly useful for battery powered laptops with
1590 APM compliant BIOSes. If you say Y here, the system time will be
1591 reset after a RESUME operation, the /proc/apm device will provide
1592 battery status information, and user-space programs will receive
1593 notification of APM "events" (e.g. battery status change).
1595 If you select "Y" here, you can disable actual use of the APM
1596 BIOS by passing the "apm=off" option to the kernel at boot time.
1598 Note that the APM support is almost completely disabled for
1599 machines with more than one CPU.
1601 In order to use APM, you will need supporting software. For location
1602 and more information, read <file:Documentation/power/pm.txt> and the
1603 Battery Powered Linux mini-HOWTO, available from
1604 <http://www.tldp.org/docs.html#howto>.
1606 This driver does not spin down disk drives (see the hdparm(8)
1607 manpage ("man 8 hdparm") for that), and it doesn't turn off
1608 VESA-compliant "green" monitors.
1610 This driver does not support the TI 4000M TravelMate and the ACER
1611 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1612 desktop machines also don't have compliant BIOSes, and this driver
1613 may cause those machines to panic during the boot phase.
1615 Generally, if you don't have a battery in your machine, there isn't
1616 much point in using this driver and you should say N. If you get
1617 random kernel OOPSes or reboots that don't seem to be related to
1618 anything, try disabling/enabling this option (or disabling/enabling
1621 Some other things you should try when experiencing seemingly random,
1624 1) make sure that you have enough swap space and that it is
1626 2) pass the "no-hlt" option to the kernel
1627 3) switch on floating point emulation in the kernel and pass
1628 the "no387" option to the kernel
1629 4) pass the "floppy=nodma" option to the kernel
1630 5) pass the "mem=4M" option to the kernel (thereby disabling
1631 all but the first 4 MB of RAM)
1632 6) make sure that the CPU is not over clocked.
1633 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1634 8) disable the cache from your BIOS settings
1635 9) install a fan for the video card or exchange video RAM
1636 10) install a better fan for the CPU
1637 11) exchange RAM chips
1638 12) exchange the motherboard.
1640 To compile this driver as a module, choose M here: the
1641 module will be called apm.
1645 config APM_IGNORE_USER_SUSPEND
1646 bool "Ignore USER SUSPEND"
1648 This option will ignore USER SUSPEND requests. On machines with a
1649 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1650 series notebooks, it is necessary to say Y because of a BIOS bug.
1652 config APM_DO_ENABLE
1653 bool "Enable PM at boot time"
1655 Enable APM features at boot time. From page 36 of the APM BIOS
1656 specification: "When disabled, the APM BIOS does not automatically
1657 power manage devices, enter the Standby State, enter the Suspend
1658 State, or take power saving steps in response to CPU Idle calls."
1659 This driver will make CPU Idle calls when Linux is idle (unless this
1660 feature is turned off -- see "Do CPU IDLE calls", below). This
1661 should always save battery power, but more complicated APM features
1662 will be dependent on your BIOS implementation. You may need to turn
1663 this option off if your computer hangs at boot time when using APM
1664 support, or if it beeps continuously instead of suspending. Turn
1665 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1666 T400CDT. This is off by default since most machines do fine without
1670 bool "Make CPU Idle calls when idle"
1672 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1673 On some machines, this can activate improved power savings, such as
1674 a slowed CPU clock rate, when the machine is idle. These idle calls
1675 are made after the idle loop has run for some length of time (e.g.,
1676 333 mS). On some machines, this will cause a hang at boot time or
1677 whenever the CPU becomes idle. (On machines with more than one CPU,
1678 this option does nothing.)
1680 config APM_DISPLAY_BLANK
1681 bool "Enable console blanking using APM"
1683 Enable console blanking using the APM. Some laptops can use this to
1684 turn off the LCD backlight when the screen blanker of the Linux
1685 virtual console blanks the screen. Note that this is only used by
1686 the virtual console screen blanker, and won't turn off the backlight
1687 when using the X Window system. This also doesn't have anything to
1688 do with your VESA-compliant power-saving monitor. Further, this
1689 option doesn't work for all laptops -- it might not turn off your
1690 backlight at all, or it might print a lot of errors to the console,
1691 especially if you are using gpm.
1693 config APM_ALLOW_INTS
1694 bool "Allow interrupts during APM BIOS calls"
1696 Normally we disable external interrupts while we are making calls to
1697 the APM BIOS as a measure to lessen the effects of a badly behaving
1698 BIOS implementation. The BIOS should reenable interrupts if it
1699 needs to. Unfortunately, some BIOSes do not -- especially those in
1700 many of the newer IBM Thinkpads. If you experience hangs when you
1701 suspend, try setting this to Y. Otherwise, say N.
1705 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1707 source "drivers/cpuidle/Kconfig"
1709 source "drivers/idle/Kconfig"
1714 menu "Bus options (PCI etc.)"
1719 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1721 Find out whether you have a PCI motherboard. PCI is the name of a
1722 bus system, i.e. the way the CPU talks to the other stuff inside
1723 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1724 VESA. If you have PCI, say Y, otherwise N.
1727 prompt "PCI access mode"
1728 depends on X86_32 && PCI
1731 On PCI systems, the BIOS can be used to detect the PCI devices and
1732 determine their configuration. However, some old PCI motherboards
1733 have BIOS bugs and may crash if this is done. Also, some embedded
1734 PCI-based systems don't have any BIOS at all. Linux can also try to
1735 detect the PCI hardware directly without using the BIOS.
1737 With this option, you can specify how Linux should detect the
1738 PCI devices. If you choose "BIOS", the BIOS will be used,
1739 if you choose "Direct", the BIOS won't be used, and if you
1740 choose "MMConfig", then PCI Express MMCONFIG will be used.
1741 If you choose "Any", the kernel will try MMCONFIG, then the
1742 direct access method and falls back to the BIOS if that doesn't
1743 work. If unsure, go with the default, which is "Any".
1748 config PCI_GOMMCONFIG
1765 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1767 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1770 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1774 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1778 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1785 bool "Support mmconfig PCI config space access"
1786 depends on X86_64 && PCI && ACPI
1789 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1790 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1792 DMA remapping (DMAR) devices support enables independent address
1793 translations for Direct Memory Access (DMA) from devices.
1794 These DMA remapping devices are reported via ACPI tables
1795 and include PCI device scope covered by these DMA
1800 prompt "Support for Graphics workaround"
1803 Current Graphics drivers tend to use physical address
1804 for DMA and avoid using DMA APIs. Setting this config
1805 option permits the IOMMU driver to set a unity map for
1806 all the OS-visible memory. Hence the driver can continue
1807 to use physical addresses for DMA.
1809 config DMAR_FLOPPY_WA
1813 Floppy disk drivers are know to bypass DMA API calls
1814 thereby failing to work when IOMMU is enabled. This
1815 workaround will setup a 1:1 mapping for the first
1816 16M to make floppy (an ISA device) work.
1819 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1820 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1822 Supports Interrupt remapping for IO-APIC and MSI devices.
1823 To use x2apic mode in the CPU's which support x2APIC enhancements or
1824 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1826 source "drivers/pci/pcie/Kconfig"
1828 source "drivers/pci/Kconfig"
1830 # x86_64 have no ISA slots, but do have ISA-style DMA.
1839 Find out whether you have ISA slots on your motherboard. ISA is the
1840 name of a bus system, i.e. the way the CPU talks to the other stuff
1841 inside your box. Other bus systems are PCI, EISA, MicroChannel
1842 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1843 newer boards don't support it. If you have ISA, say Y, otherwise N.
1849 The Extended Industry Standard Architecture (EISA) bus was
1850 developed as an open alternative to the IBM MicroChannel bus.
1852 The EISA bus provided some of the features of the IBM MicroChannel
1853 bus while maintaining backward compatibility with cards made for
1854 the older ISA bus. The EISA bus saw limited use between 1988 and
1855 1995 when it was made obsolete by the PCI bus.
1857 Say Y here if you are building a kernel for an EISA-based machine.
1861 source "drivers/eisa/Kconfig"
1866 MicroChannel Architecture is found in some IBM PS/2 machines and
1867 laptops. It is a bus system similar to PCI or ISA. See
1868 <file:Documentation/mca.txt> (and especially the web page given
1869 there) before attempting to build an MCA bus kernel.
1871 source "drivers/mca/Kconfig"
1874 tristate "NatSemi SCx200 support"
1876 This provides basic support for National Semiconductor's
1877 (now AMD's) Geode processors. The driver probes for the
1878 PCI-IDs of several on-chip devices, so its a good dependency
1879 for other scx200_* drivers.
1881 If compiled as a module, the driver is named scx200.
1883 config SCx200HR_TIMER
1884 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1885 depends on SCx200 && GENERIC_TIME
1888 This driver provides a clocksource built upon the on-chip
1889 27MHz high-resolution timer. Its also a workaround for
1890 NSC Geode SC-1100's buggy TSC, which loses time when the
1891 processor goes idle (as is done by the scheduler). The
1892 other workaround is idle=poll boot option.
1894 config GEODE_MFGPT_TIMER
1896 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1897 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1899 This driver provides a clock event source based on the MFGPT
1900 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1901 MFGPTs have a better resolution and max interval than the
1902 generic PIT, and are suitable for use as high-res timers.
1905 bool "One Laptop Per Child support"
1908 Add support for detecting the unique features of the OLPC
1915 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1917 source "drivers/pcmcia/Kconfig"
1919 source "drivers/pci/hotplug/Kconfig"
1924 menu "Executable file formats / Emulations"
1926 source "fs/Kconfig.binfmt"
1928 config IA32_EMULATION
1929 bool "IA32 Emulation"
1931 select COMPAT_BINFMT_ELF
1933 Include code to run 32-bit programs under a 64-bit kernel. You should
1934 likely turn this on, unless you're 100% sure that you don't have any
1935 32-bit programs left.
1938 tristate "IA32 a.out support"
1939 depends on IA32_EMULATION
1941 Support old a.out binaries in the 32bit emulation.
1945 depends on IA32_EMULATION
1947 config COMPAT_FOR_U64_ALIGNMENT
1951 config SYSVIPC_COMPAT
1953 depends on COMPAT && SYSVIPC
1958 config HAVE_ATOMIC_IOMAP
1962 source "net/Kconfig"
1964 source "drivers/Kconfig"
1966 source "drivers/firmware/Kconfig"
1970 source "arch/x86/Kconfig.debug"
1972 source "security/Kconfig"
1974 source "crypto/Kconfig"
1976 source "arch/x86/kvm/Kconfig"
1978 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob