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 HAVE_KRETPROBES
31 select HAVE_FTRACE_MCOUNT_RECORD
32 select HAVE_DYNAMIC_FTRACE
33 select HAVE_FUNCTION_TRACER
34 select HAVE_FUNCTION_GRAPH_TRACER
35 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
36 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
37 select HAVE_ARCH_KGDB if !X86_VOYAGER
38 select HAVE_ARCH_TRACEHOOK
39 select HAVE_GENERIC_DMA_COHERENT if X86_32
40 select HAVE_EFFICIENT_UNALIGNED_ACCESS
41 select USER_STACKTRACE_SUPPORT
45 default "arch/x86/configs/i386_defconfig" if X86_32
46 default "arch/x86/configs/x86_64_defconfig" if X86_64
51 config GENERIC_CMOS_UPDATE
54 config CLOCKSOURCE_WATCHDOG
57 config GENERIC_CLOCKEVENTS
60 config GENERIC_CLOCKEVENTS_BROADCAST
62 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
64 config LOCKDEP_SUPPORT
67 config STACKTRACE_SUPPORT
70 config HAVE_LATENCYTOP_SUPPORT
73 config FAST_CMPXCHG_LOCAL
86 config GENERIC_ISA_DMA
95 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
97 config GENERIC_BUG_RELATIVE_POINTERS
100 config GENERIC_HWEIGHT
106 config ARCH_MAY_HAVE_PC_FDC
109 config RWSEM_GENERIC_SPINLOCK
112 config RWSEM_XCHGADD_ALGORITHM
115 config ARCH_HAS_CPU_IDLE_WAIT
118 config GENERIC_CALIBRATE_DELAY
121 config GENERIC_TIME_VSYSCALL
125 config ARCH_HAS_CPU_RELAX
128 config ARCH_HAS_DEFAULT_IDLE
131 config ARCH_HAS_CACHE_LINE_SIZE
134 config HAVE_SETUP_PER_CPU_AREA
135 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
137 config HAVE_CPUMASK_OF_CPU_MAP
140 config ARCH_HIBERNATION_POSSIBLE
142 depends on !SMP || !X86_VOYAGER
144 config ARCH_SUSPEND_POSSIBLE
146 depends on !X86_VOYAGER
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
178 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
181 config USE_GENERIC_SMP_HELPERS
187 depends on X86_32 && SMP
191 depends on X86_64 && SMP
196 depends on (X86_32 && !X86_VOYAGER) || X86_64
199 config X86_BIOS_REBOOT
201 depends on !X86_VOYAGER
204 config X86_TRAMPOLINE
206 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
211 source "init/Kconfig"
212 source "kernel/Kconfig.freezer"
214 menu "Processor type and features"
216 source "kernel/time/Kconfig"
219 bool "Symmetric multi-processing support"
221 This enables support for systems with more than one CPU. If you have
222 a system with only one CPU, like most personal computers, say N. If
223 you have a system with more than one CPU, say Y.
225 If you say N here, the kernel will run on single and multiprocessor
226 machines, but will use only one CPU of a multiprocessor machine. If
227 you say Y here, the kernel will run on many, but not all,
228 singleprocessor machines. On a singleprocessor machine, the kernel
229 will run faster if you say N here.
231 Note that if you say Y here and choose architecture "586" or
232 "Pentium" under "Processor family", the kernel will not work on 486
233 architectures. Similarly, multiprocessor kernels for the "PPro"
234 architecture may not work on all Pentium based boards.
236 People using multiprocessor machines who say Y here should also say
237 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
238 Management" code will be disabled if you say Y here.
240 See also <file:Documentation/i386/IO-APIC.txt>,
241 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
242 <http://www.tldp.org/docs.html#howto>.
244 If you don't know what to do here, say N.
246 config X86_HAS_BOOT_CPU_ID
248 depends on X86_VOYAGER
250 config X86_FIND_SMP_CONFIG
252 depends on X86_MPPARSE || X86_VOYAGER
255 bool "Enable MPS table" if ACPI
257 depends on X86_LOCAL_APIC
259 For old smp systems that do not have proper acpi support. Newer systems
260 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
263 prompt "Subarchitecture Type"
269 Choose this option if your computer is a standard PC or compatible.
275 Select this for an AMD Elan processor.
277 Do not use this option for K6/Athlon/Opteron processors!
279 If unsure, choose "PC-compatible" instead.
283 depends on X86_32 && (SMP || BROKEN) && !PCI
285 Voyager is an MCA-based 32-way capable SMP architecture proprietary
286 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
290 If you do not specifically know you have a Voyager based machine,
291 say N here, otherwise the kernel you build will not be bootable.
293 config X86_GENERICARCH
294 bool "Generic architecture"
297 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
298 subarchitectures. It is intended for a generic binary kernel.
299 if you select them all, kernel will probe it one by one. and will
305 bool "NUMAQ (IBM/Sequent)"
306 depends on SMP && X86_32 && PCI && X86_MPPARSE
309 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
310 NUMA multiquad box. This changes the way that processors are
311 bootstrapped, and uses Clustered Logical APIC addressing mode instead
312 of Flat Logical. You will need a new lynxer.elf file to flash your
313 firmware with - send email to <Martin.Bligh@us.ibm.com>.
316 bool "Summit/EXA (IBM x440)"
317 depends on X86_32 && SMP
319 This option is needed for IBM systems that use the Summit/EXA chipset.
320 In particular, it is needed for the x440.
323 bool "Support for Unisys ES7000 IA32 series"
324 depends on X86_32 && SMP
326 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
327 supposed to run on an IA32-based Unisys ES7000 system.
330 bool "Support for big SMP systems with more than 8 CPUs"
331 depends on X86_32 && SMP
333 This option is needed for the systems that have more than 8 CPUs
334 and if the system is not of any sub-arch type above.
339 bool "Support for ScaleMP vSMP"
341 depends on X86_64 && PCI
343 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
344 supposed to run on these EM64T-based machines. Only choose this option
345 if you have one of these machines.
350 bool "SGI 320/540 (Visual Workstation)"
351 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
353 The SGI Visual Workstation series is an IA32-based workstation
354 based on SGI systems chips with some legacy PC hardware attached.
356 Say Y here to create a kernel to run on the SGI 320 or 540.
358 A kernel compiled for the Visual Workstation will run on general
359 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
362 bool "RDC R-321x SoC"
365 select X86_REBOOTFIXUPS
367 This option is needed for RDC R-321x system-on-chip, also known
369 If you don't have one of these chips, you should say N here.
371 config SCHED_OMIT_FRAME_POINTER
373 prompt "Single-depth WCHAN output"
376 Calculate simpler /proc/<PID>/wchan values. If this option
377 is disabled then wchan values will recurse back to the
378 caller function. This provides more accurate wchan values,
379 at the expense of slightly more scheduling overhead.
381 If in doubt, say "Y".
383 menuconfig PARAVIRT_GUEST
384 bool "Paravirtualized guest support"
386 Say Y here to get to see options related to running Linux under
387 various hypervisors. This option alone does not add any kernel code.
389 If you say N, all options in this submenu will be skipped and disabled.
393 source "arch/x86/xen/Kconfig"
396 bool "VMI Guest support"
399 depends on !X86_VOYAGER
401 VMI provides a paravirtualized interface to the VMware ESX server
402 (it could be used by other hypervisors in theory too, but is not
403 at the moment), by linking the kernel to a GPL-ed ROM module
404 provided by the hypervisor.
407 bool "KVM paravirtualized clock"
409 select PARAVIRT_CLOCK
410 depends on !X86_VOYAGER
412 Turning on this option will allow you to run a paravirtualized clock
413 when running over the KVM hypervisor. Instead of relying on a PIT
414 (or probably other) emulation by the underlying device model, the host
415 provides the guest with timing infrastructure such as time of day, and
419 bool "KVM Guest support"
421 depends on !X86_VOYAGER
423 This option enables various optimizations for running under the KVM
426 source "arch/x86/lguest/Kconfig"
429 bool "Enable paravirtualization code"
430 depends on !X86_VOYAGER
432 This changes the kernel so it can modify itself when it is run
433 under a hypervisor, potentially improving performance significantly
434 over full virtualization. However, when run without a hypervisor
435 the kernel is theoretically slower and slightly larger.
437 config PARAVIRT_CLOCK
443 config PARAVIRT_DEBUG
444 bool "paravirt-ops debugging"
445 depends on PARAVIRT && DEBUG_KERNEL
447 Enable to debug paravirt_ops internals. Specifically, BUG if
448 a paravirt_op is missing when it is called.
453 This option adds a kernel parameter 'memtest', which allows memtest
455 memtest=0, mean disabled; -- default
456 memtest=1, mean do 1 test pattern;
458 memtest=4, mean do 4 test patterns.
459 If you are unsure how to answer this question, answer N.
461 config X86_SUMMIT_NUMA
463 depends on X86_32 && NUMA && X86_GENERICARCH
465 config X86_CYCLONE_TIMER
467 depends on X86_GENERICARCH
469 source "arch/x86/Kconfig.cpu"
473 prompt "HPET Timer Support" if X86_32
475 Use the IA-PC HPET (High Precision Event Timer) to manage
476 time in preference to the PIT and RTC, if a HPET is
478 HPET is the next generation timer replacing legacy 8254s.
479 The HPET provides a stable time base on SMP
480 systems, unlike the TSC, but it is more expensive to access,
481 as it is off-chip. You can find the HPET spec at
482 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
484 You can safely choose Y here. However, HPET will only be
485 activated if the platform and the BIOS support this feature.
486 Otherwise the 8254 will be used for timing services.
488 Choose N to continue using the legacy 8254 timer.
490 config HPET_EMULATE_RTC
492 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
494 # Mark as embedded because too many people got it wrong.
495 # The code disables itself when not needed.
498 bool "Enable DMI scanning" if EMBEDDED
500 Enabled scanning of DMI to identify machine quirks. Say Y
501 here unless you have verified that your setup is not
502 affected by entries in the DMI blacklist. Required by PNP
506 bool "GART IOMMU support" if EMBEDDED
510 depends on X86_64 && PCI
512 Support for full DMA access of devices with 32bit memory access only
513 on systems with more than 3GB. This is usually needed for USB,
514 sound, many IDE/SATA chipsets and some other devices.
515 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
516 based hardware IOMMU and a software bounce buffer based IOMMU used
517 on Intel systems and as fallback.
518 The code is only active when needed (enough memory and limited
519 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
523 bool "IBM Calgary IOMMU support"
525 depends on X86_64 && PCI && EXPERIMENTAL
527 Support for hardware IOMMUs in IBM's xSeries x366 and x460
528 systems. Needed to run systems with more than 3GB of memory
529 properly with 32-bit PCI devices that do not support DAC
530 (Double Address Cycle). Calgary also supports bus level
531 isolation, where all DMAs pass through the IOMMU. This
532 prevents them from going anywhere except their intended
533 destination. This catches hard-to-find kernel bugs and
534 mis-behaving drivers and devices that do not use the DMA-API
535 properly to set up their DMA buffers. The IOMMU can be
536 turned off at boot time with the iommu=off parameter.
537 Normally the kernel will make the right choice by itself.
540 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
542 prompt "Should Calgary be enabled by default?"
543 depends on CALGARY_IOMMU
545 Should Calgary be enabled by default? if you choose 'y', Calgary
546 will be used (if it exists). If you choose 'n', Calgary will not be
547 used even if it exists. If you choose 'n' and would like to use
548 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
552 bool "AMD IOMMU support"
555 depends on X86_64 && PCI && ACPI
557 With this option you can enable support for AMD IOMMU hardware in
558 your system. An IOMMU is a hardware component which provides
559 remapping of DMA memory accesses from devices. With an AMD IOMMU you
560 can isolate the the DMA memory of different devices and protect the
561 system from misbehaving device drivers or hardware.
563 You can find out if your system has an AMD IOMMU if you look into
564 your BIOS for an option to enable it or if you have an IVRS ACPI
567 # need this always selected by IOMMU for the VIA workaround
571 Support for software bounce buffers used on x86-64 systems
572 which don't have a hardware IOMMU (e.g. the current generation
573 of Intel's x86-64 CPUs). Using this PCI devices which can only
574 access 32-bits of memory can be used on systems with more than
575 3 GB of memory. If unsure, say Y.
578 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
581 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
582 depends on X86_64 && SMP && BROKEN
585 Configure maximum number of CPUS and NUMA Nodes for this architecture.
589 int "Maximum number of CPUs (2-512)" if !MAXSMP
592 default "4096" if MAXSMP
593 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
596 This allows you to specify the maximum number of CPUs which this
597 kernel will support. The maximum supported value is 512 and the
598 minimum value which makes sense is 2.
600 This is purely to save memory - each supported CPU adds
601 approximately eight kilobytes to the kernel image.
604 bool "SMT (Hyperthreading) scheduler support"
607 SMT scheduler support improves the CPU scheduler's decision making
608 when dealing with Intel Pentium 4 chips with HyperThreading at a
609 cost of slightly increased overhead in some places. If unsure say
614 prompt "Multi-core scheduler support"
617 Multi-core scheduler support improves the CPU scheduler's decision
618 making when dealing with multi-core CPU chips at a cost of slightly
619 increased overhead in some places. If unsure say N here.
621 source "kernel/Kconfig.preempt"
624 bool "Local APIC support on uniprocessors"
625 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
627 A local APIC (Advanced Programmable Interrupt Controller) is an
628 integrated interrupt controller in the CPU. If you have a single-CPU
629 system which has a processor with a local APIC, you can say Y here to
630 enable and use it. If you say Y here even though your machine doesn't
631 have a local APIC, then the kernel will still run with no slowdown at
632 all. The local APIC supports CPU-generated self-interrupts (timer,
633 performance counters), and the NMI watchdog which detects hard
637 bool "IO-APIC support on uniprocessors"
638 depends on X86_UP_APIC
640 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
641 SMP-capable replacement for PC-style interrupt controllers. Most
642 SMP systems and many recent uniprocessor systems have one.
644 If you have a single-CPU system with an IO-APIC, you can say Y here
645 to use it. If you say Y here even though your machine doesn't have
646 an IO-APIC, then the kernel will still run with no slowdown at all.
648 config X86_LOCAL_APIC
650 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
654 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
656 config X86_VISWS_APIC
658 depends on X86_32 && X86_VISWS
660 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
661 bool "Reroute for broken boot IRQs"
663 depends on X86_IO_APIC
665 This option enables a workaround that fixes a source of
666 spurious interrupts. This is recommended when threaded
667 interrupt handling is used on systems where the generation of
668 superfluous "boot interrupts" cannot be disabled.
670 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
671 entry in the chipset's IO-APIC is masked (as, e.g. the RT
672 kernel does during interrupt handling). On chipsets where this
673 boot IRQ generation cannot be disabled, this workaround keeps
674 the original IRQ line masked so that only the equivalent "boot
675 IRQ" is delivered to the CPUs. The workaround also tells the
676 kernel to set up the IRQ handler on the boot IRQ line. In this
677 way only one interrupt is delivered to the kernel. Otherwise
678 the spurious second interrupt may cause the kernel to bring
679 down (vital) interrupt lines.
681 Only affects "broken" chipsets. Interrupt sharing may be
682 increased on these systems.
685 bool "Machine Check Exception"
686 depends on !X86_VOYAGER
688 Machine Check Exception support allows the processor to notify the
689 kernel if it detects a problem (e.g. overheating, component failure).
690 The action the kernel takes depends on the severity of the problem,
691 ranging from a warning message on the console, to halting the machine.
692 Your processor must be a Pentium or newer to support this - check the
693 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
694 have a design flaw which leads to false MCE events - hence MCE is
695 disabled on all P5 processors, unless explicitly enabled with "mce"
696 as a boot argument. Similarly, if MCE is built in and creates a
697 problem on some new non-standard machine, you can boot with "nomce"
698 to disable it. MCE support simply ignores non-MCE processors like
699 the 386 and 486, so nearly everyone can say Y here.
703 prompt "Intel MCE features"
704 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
706 Additional support for intel specific MCE features such as
711 prompt "AMD MCE features"
712 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
714 Additional support for AMD specific MCE features such as
715 the DRAM Error Threshold.
717 config X86_MCE_NONFATAL
718 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
719 depends on X86_32 && X86_MCE
721 Enabling this feature starts a timer that triggers every 5 seconds which
722 will look at the machine check registers to see if anything happened.
723 Non-fatal problems automatically get corrected (but still logged).
724 Disable this if you don't want to see these messages.
725 Seeing the messages this option prints out may be indicative of dying
726 or out-of-spec (ie, overclocked) hardware.
727 This option only does something on certain CPUs.
728 (AMD Athlon/Duron and Intel Pentium 4)
730 config X86_MCE_P4THERMAL
731 bool "check for P4 thermal throttling interrupt."
732 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
734 Enabling this feature will cause a message to be printed when the P4
735 enters thermal throttling.
738 bool "Enable VM86 support" if EMBEDDED
742 This option is required by programs like DOSEMU to run 16-bit legacy
743 code on X86 processors. It also may be needed by software like
744 XFree86 to initialize some video cards via BIOS. Disabling this
745 option saves about 6k.
748 tristate "Toshiba Laptop support"
751 This adds a driver to safely access the System Management Mode of
752 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
753 not work on models with a Phoenix BIOS. The System Management Mode
754 is used to set the BIOS and power saving options on Toshiba portables.
756 For information on utilities to make use of this driver see the
757 Toshiba Linux utilities web site at:
758 <http://www.buzzard.org.uk/toshiba/>.
760 Say Y if you intend to run this kernel on a Toshiba portable.
764 tristate "Dell laptop support"
766 This adds a driver to safely access the System Management Mode
767 of the CPU on the Dell Inspiron 8000. The System Management Mode
768 is used to read cpu temperature and cooling fan status and to
769 control the fans on the I8K portables.
771 This driver has been tested only on the Inspiron 8000 but it may
772 also work with other Dell laptops. You can force loading on other
773 models by passing the parameter `force=1' to the module. Use at
776 For information on utilities to make use of this driver see the
777 I8K Linux utilities web site at:
778 <http://people.debian.org/~dz/i8k/>
780 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
783 config X86_REBOOTFIXUPS
784 bool "Enable X86 board specific fixups for reboot"
787 This enables chipset and/or board specific fixups to be done
788 in order to get reboot to work correctly. This is only needed on
789 some combinations of hardware and BIOS. The symptom, for which
790 this config is intended, is when reboot ends with a stalled/hung
793 Currently, the only fixup is for the Geode machines using
794 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
796 Say Y if you want to enable the fixup. Currently, it's safe to
797 enable this option even if you don't need it.
801 tristate "/dev/cpu/microcode - microcode support"
804 If you say Y here, you will be able to update the microcode on
805 certain Intel and AMD processors. The Intel support is for the
806 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
807 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
808 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
809 You will obviously need the actual microcode binary data itself
810 which is not shipped with the Linux kernel.
812 This option selects the general module only, you need to select
813 at least one vendor specific module as well.
815 To compile this driver as a module, choose M here: the
816 module will be called microcode.
818 config MICROCODE_INTEL
819 bool "Intel microcode patch loading support"
824 This options enables microcode patch loading support for Intel
827 For latest news and information on obtaining all the required
828 Intel ingredients for this driver, check:
829 <http://www.urbanmyth.org/microcode/>.
832 bool "AMD microcode patch loading support"
836 If you select this option, microcode patch loading support for AMD
837 processors will be enabled.
839 config MICROCODE_OLD_INTERFACE
844 tristate "/dev/cpu/*/msr - Model-specific register support"
846 This device gives privileged processes access to the x86
847 Model-Specific Registers (MSRs). It is a character device with
848 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
849 MSR accesses are directed to a specific CPU on multi-processor
853 tristate "/dev/cpu/*/cpuid - CPU information support"
855 This device gives processes access to the x86 CPUID instruction to
856 be executed on a specific processor. It is a character device
857 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
861 prompt "High Memory Support"
862 default HIGHMEM4G if !X86_NUMAQ
863 default HIGHMEM64G if X86_NUMAQ
868 depends on !X86_NUMAQ
870 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
871 However, the address space of 32-bit x86 processors is only 4
872 Gigabytes large. That means that, if you have a large amount of
873 physical memory, not all of it can be "permanently mapped" by the
874 kernel. The physical memory that's not permanently mapped is called
877 If you are compiling a kernel which will never run on a machine with
878 more than 1 Gigabyte total physical RAM, answer "off" here (default
879 choice and suitable for most users). This will result in a "3GB/1GB"
880 split: 3GB are mapped so that each process sees a 3GB virtual memory
881 space and the remaining part of the 4GB virtual memory space is used
882 by the kernel to permanently map as much physical memory as
885 If the machine has between 1 and 4 Gigabytes physical RAM, then
888 If more than 4 Gigabytes is used then answer "64GB" here. This
889 selection turns Intel PAE (Physical Address Extension) mode on.
890 PAE implements 3-level paging on IA32 processors. PAE is fully
891 supported by Linux, PAE mode is implemented on all recent Intel
892 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
893 then the kernel will not boot on CPUs that don't support PAE!
895 The actual amount of total physical memory will either be
896 auto detected or can be forced by using a kernel command line option
897 such as "mem=256M". (Try "man bootparam" or see the documentation of
898 your boot loader (lilo or loadlin) about how to pass options to the
899 kernel at boot time.)
901 If unsure, say "off".
905 depends on !X86_NUMAQ
907 Select this if you have a 32-bit processor and between 1 and 4
908 gigabytes of physical RAM.
912 depends on !M386 && !M486
915 Select this if you have a 32-bit processor and more than 4
916 gigabytes of physical RAM.
921 depends on EXPERIMENTAL
922 prompt "Memory split" if EMBEDDED
926 Select the desired split between kernel and user memory.
928 If the address range available to the kernel is less than the
929 physical memory installed, the remaining memory will be available
930 as "high memory". Accessing high memory is a little more costly
931 than low memory, as it needs to be mapped into the kernel first.
932 Note that increasing the kernel address space limits the range
933 available to user programs, making the address space there
934 tighter. Selecting anything other than the default 3G/1G split
935 will also likely make your kernel incompatible with binary-only
938 If you are not absolutely sure what you are doing, leave this
942 bool "3G/1G user/kernel split"
943 config VMSPLIT_3G_OPT
945 bool "3G/1G user/kernel split (for full 1G low memory)"
947 bool "2G/2G user/kernel split"
948 config VMSPLIT_2G_OPT
950 bool "2G/2G user/kernel split (for full 2G low memory)"
952 bool "1G/3G user/kernel split"
957 default 0xB0000000 if VMSPLIT_3G_OPT
958 default 0x80000000 if VMSPLIT_2G
959 default 0x78000000 if VMSPLIT_2G_OPT
960 default 0x40000000 if VMSPLIT_1G
966 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
969 bool "PAE (Physical Address Extension) Support"
970 depends on X86_32 && !HIGHMEM4G
972 PAE is required for NX support, and furthermore enables
973 larger swapspace support for non-overcommit purposes. It
974 has the cost of more pagetable lookup overhead, and also
975 consumes more pagetable space per process.
977 config ARCH_PHYS_ADDR_T_64BIT
978 def_bool X86_64 || X86_PAE
980 config DIRECT_GBPAGES
981 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
985 Allow the kernel linear mapping to use 1GB pages on CPUs that
986 support it. This can improve the kernel's performance a tiny bit by
987 reducing TLB pressure. If in doubt, say "Y".
989 # Common NUMA Features
991 bool "Numa Memory Allocation and Scheduler Support"
993 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
995 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
997 Enable NUMA (Non Uniform Memory Access) support.
999 The kernel will try to allocate memory used by a CPU on the
1000 local memory controller of the CPU and add some more
1001 NUMA awareness to the kernel.
1003 For 64-bit this is recommended if the system is Intel Core i7
1004 (or later), AMD Opteron, or EM64T NUMA.
1006 For 32-bit this is only needed on (rare) 32-bit-only platforms
1007 that support NUMA topologies, such as NUMAQ / Summit, or if you
1008 boot a 32-bit kernel on a 64-bit NUMA platform.
1010 Otherwise, you should say N.
1012 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1013 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1017 prompt "Old style AMD Opteron NUMA detection"
1018 depends on X86_64 && NUMA && PCI
1020 Enable K8 NUMA node topology detection. You should say Y here if
1021 you have a multi processor AMD K8 system. This uses an old
1022 method to read the NUMA configuration directly from the builtin
1023 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1024 instead, which also takes priority if both are compiled in.
1026 config X86_64_ACPI_NUMA
1028 prompt "ACPI NUMA detection"
1029 depends on X86_64 && NUMA && ACPI && PCI
1032 Enable ACPI SRAT based node topology detection.
1034 # Some NUMA nodes have memory ranges that span
1035 # other nodes. Even though a pfn is valid and
1036 # between a node's start and end pfns, it may not
1037 # reside on that node. See memmap_init_zone()
1039 config NODES_SPAN_OTHER_NODES
1041 depends on X86_64_ACPI_NUMA
1044 bool "NUMA emulation"
1045 depends on X86_64 && NUMA
1047 Enable NUMA emulation. A flat machine will be split
1048 into virtual nodes when booted with "numa=fake=N", where N is the
1049 number of nodes. This is only useful for debugging.
1052 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1054 default "9" if MAXSMP
1055 default "6" if X86_64
1056 default "4" if X86_NUMAQ
1058 depends on NEED_MULTIPLE_NODES
1060 Specify the maximum number of NUMA Nodes available on the target
1061 system. Increases memory reserved to accomodate various tables.
1063 config HAVE_ARCH_BOOTMEM_NODE
1065 depends on X86_32 && NUMA
1067 config ARCH_HAVE_MEMORY_PRESENT
1069 depends on X86_32 && DISCONTIGMEM
1071 config NEED_NODE_MEMMAP_SIZE
1073 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1075 config HAVE_ARCH_ALLOC_REMAP
1077 depends on X86_32 && NUMA
1079 config ARCH_FLATMEM_ENABLE
1081 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1083 config ARCH_DISCONTIGMEM_ENABLE
1085 depends on NUMA && X86_32
1087 config ARCH_DISCONTIGMEM_DEFAULT
1089 depends on NUMA && X86_32
1091 config ARCH_SPARSEMEM_DEFAULT
1095 config ARCH_SPARSEMEM_ENABLE
1097 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1098 select SPARSEMEM_STATIC if X86_32
1099 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1101 config ARCH_SELECT_MEMORY_MODEL
1103 depends on ARCH_SPARSEMEM_ENABLE
1105 config ARCH_MEMORY_PROBE
1107 depends on MEMORY_HOTPLUG
1112 bool "Allocate 3rd-level pagetables from highmem"
1113 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1115 The VM uses one page table entry for each page of physical memory.
1116 For systems with a lot of RAM, this can be wasteful of precious
1117 low memory. Setting this option will put user-space page table
1118 entries in high memory.
1120 config X86_CHECK_BIOS_CORRUPTION
1121 bool "Check for low memory corruption"
1123 Periodically check for memory corruption in low memory, which
1124 is suspected to be caused by BIOS. Even when enabled in the
1125 configuration, it is disabled at runtime. Enable it by
1126 setting "memory_corruption_check=1" on the kernel command
1127 line. By default it scans the low 64k of memory every 60
1128 seconds; see the memory_corruption_check_size and
1129 memory_corruption_check_period parameters in
1130 Documentation/kernel-parameters.txt to adjust this.
1132 When enabled with the default parameters, this option has
1133 almost no overhead, as it reserves a relatively small amount
1134 of memory and scans it infrequently. It both detects corruption
1135 and prevents it from affecting the running system.
1137 It is, however, intended as a diagnostic tool; if repeatable
1138 BIOS-originated corruption always affects the same memory,
1139 you can use memmap= to prevent the kernel from using that
1142 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1143 bool "Set the default setting of memory_corruption_check"
1144 depends on X86_CHECK_BIOS_CORRUPTION
1147 Set whether the default state of memory_corruption_check is
1150 config X86_RESERVE_LOW_64K
1151 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1154 Reserve the first 64K of physical RAM on BIOSes that are known
1155 to potentially corrupt that memory range. A numbers of BIOSes are
1156 known to utilize this area during suspend/resume, so it must not
1157 be used by the kernel.
1159 Set this to N if you are absolutely sure that you trust the BIOS
1160 to get all its memory reservations and usages right.
1162 If you have doubts about the BIOS (e.g. suspend/resume does not
1163 work or there's kernel crashes after certain hardware hotplug
1164 events) and it's not AMI or Phoenix, then you might want to enable
1165 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1166 corruption patterns.
1170 config MATH_EMULATION
1172 prompt "Math emulation" if X86_32
1174 Linux can emulate a math coprocessor (used for floating point
1175 operations) if you don't have one. 486DX and Pentium processors have
1176 a math coprocessor built in, 486SX and 386 do not, unless you added
1177 a 487DX or 387, respectively. (The messages during boot time can
1178 give you some hints here ["man dmesg"].) Everyone needs either a
1179 coprocessor or this emulation.
1181 If you don't have a math coprocessor, you need to say Y here; if you
1182 say Y here even though you have a coprocessor, the coprocessor will
1183 be used nevertheless. (This behavior can be changed with the kernel
1184 command line option "no387", which comes handy if your coprocessor
1185 is broken. Try "man bootparam" or see the documentation of your boot
1186 loader (lilo or loadlin) about how to pass options to the kernel at
1187 boot time.) This means that it is a good idea to say Y here if you
1188 intend to use this kernel on different machines.
1190 More information about the internals of the Linux math coprocessor
1191 emulation can be found in <file:arch/x86/math-emu/README>.
1193 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1194 kernel, it won't hurt.
1197 bool "MTRR (Memory Type Range Register) support"
1199 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1200 the Memory Type Range Registers (MTRRs) may be used to control
1201 processor access to memory ranges. This is most useful if you have
1202 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1203 allows bus write transfers to be combined into a larger transfer
1204 before bursting over the PCI/AGP bus. This can increase performance
1205 of image write operations 2.5 times or more. Saying Y here creates a
1206 /proc/mtrr file which may be used to manipulate your processor's
1207 MTRRs. Typically the X server should use this.
1209 This code has a reasonably generic interface so that similar
1210 control registers on other processors can be easily supported
1213 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1214 Registers (ARRs) which provide a similar functionality to MTRRs. For
1215 these, the ARRs are used to emulate the MTRRs.
1216 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1217 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1218 write-combining. All of these processors are supported by this code
1219 and it makes sense to say Y here if you have one of them.
1221 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1222 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1223 can lead to all sorts of problems, so it's good to say Y here.
1225 You can safely say Y even if your machine doesn't have MTRRs, you'll
1226 just add about 9 KB to your kernel.
1228 See <file:Documentation/x86/mtrr.txt> for more information.
1230 config MTRR_SANITIZER
1232 prompt "MTRR cleanup support"
1235 Convert MTRR layout from continuous to discrete, so X drivers can
1236 add writeback entries.
1238 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1239 The largest mtrr entry size for a continous block can be set with
1244 config MTRR_SANITIZER_ENABLE_DEFAULT
1245 int "MTRR cleanup enable value (0-1)"
1248 depends on MTRR_SANITIZER
1250 Enable mtrr cleanup default value
1252 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1253 int "MTRR cleanup spare reg num (0-7)"
1256 depends on MTRR_SANITIZER
1258 mtrr cleanup spare entries default, it can be changed via
1259 mtrr_spare_reg_nr=N on the kernel command line.
1263 prompt "x86 PAT support"
1266 Use PAT attributes to setup page level cache control.
1268 PATs are the modern equivalents of MTRRs and are much more
1269 flexible than MTRRs.
1271 Say N here if you see bootup problems (boot crash, boot hang,
1272 spontaneous reboots) or a non-working video driver.
1277 bool "EFI runtime service support"
1280 This enables the kernel to use EFI runtime services that are
1281 available (such as the EFI variable services).
1283 This option is only useful on systems that have EFI firmware.
1284 In addition, you should use the latest ELILO loader available
1285 at <http://elilo.sourceforge.net> in order to take advantage
1286 of EFI runtime services. However, even with this option, the
1287 resultant kernel should continue to boot on existing non-EFI
1292 prompt "Enable seccomp to safely compute untrusted bytecode"
1294 This kernel feature is useful for number crunching applications
1295 that may need to compute untrusted bytecode during their
1296 execution. By using pipes or other transports made available to
1297 the process as file descriptors supporting the read/write
1298 syscalls, it's possible to isolate those applications in
1299 their own address space using seccomp. Once seccomp is
1300 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1301 and the task is only allowed to execute a few safe syscalls
1302 defined by each seccomp mode.
1304 If unsure, say Y. Only embedded should say N here.
1306 config CC_STACKPROTECTOR
1307 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1308 depends on X86_64 && EXPERIMENTAL && BROKEN
1310 This option turns on the -fstack-protector GCC feature. This
1311 feature puts, at the beginning of critical functions, a canary
1312 value on the stack just before the return address, and validates
1313 the value just before actually returning. Stack based buffer
1314 overflows (that need to overwrite this return address) now also
1315 overwrite the canary, which gets detected and the attack is then
1316 neutralized via a kernel panic.
1318 This feature requires gcc version 4.2 or above, or a distribution
1319 gcc with the feature backported. Older versions are automatically
1320 detected and for those versions, this configuration option is ignored.
1322 config CC_STACKPROTECTOR_ALL
1323 bool "Use stack-protector for all functions"
1324 depends on CC_STACKPROTECTOR
1326 Normally, GCC only inserts the canary value protection for
1327 functions that use large-ish on-stack buffers. By enabling
1328 this option, GCC will be asked to do this for ALL functions.
1330 source kernel/Kconfig.hz
1333 bool "kexec system call"
1334 depends on X86_BIOS_REBOOT
1336 kexec is a system call that implements the ability to shutdown your
1337 current kernel, and to start another kernel. It is like a reboot
1338 but it is independent of the system firmware. And like a reboot
1339 you can start any kernel with it, not just Linux.
1341 The name comes from the similarity to the exec system call.
1343 It is an ongoing process to be certain the hardware in a machine
1344 is properly shutdown, so do not be surprised if this code does not
1345 initially work for you. It may help to enable device hotplugging
1346 support. As of this writing the exact hardware interface is
1347 strongly in flux, so no good recommendation can be made.
1350 bool "kernel crash dumps"
1351 depends on X86_64 || (X86_32 && HIGHMEM)
1353 Generate crash dump after being started by kexec.
1354 This should be normally only set in special crash dump kernels
1355 which are loaded in the main kernel with kexec-tools into
1356 a specially reserved region and then later executed after
1357 a crash by kdump/kexec. The crash dump kernel must be compiled
1358 to a memory address not used by the main kernel or BIOS using
1359 PHYSICAL_START, or it must be built as a relocatable image
1360 (CONFIG_RELOCATABLE=y).
1361 For more details see Documentation/kdump/kdump.txt
1364 bool "kexec jump (EXPERIMENTAL)"
1365 depends on EXPERIMENTAL
1366 depends on KEXEC && HIBERNATION && X86_32
1368 Jump between original kernel and kexeced kernel and invoke
1369 code in physical address mode via KEXEC
1371 config PHYSICAL_START
1372 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1373 default "0x1000000" if X86_NUMAQ
1374 default "0x200000" if X86_64
1377 This gives the physical address where the kernel is loaded.
1379 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1380 bzImage will decompress itself to above physical address and
1381 run from there. Otherwise, bzImage will run from the address where
1382 it has been loaded by the boot loader and will ignore above physical
1385 In normal kdump cases one does not have to set/change this option
1386 as now bzImage can be compiled as a completely relocatable image
1387 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1388 address. This option is mainly useful for the folks who don't want
1389 to use a bzImage for capturing the crash dump and want to use a
1390 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1391 to be specifically compiled to run from a specific memory area
1392 (normally a reserved region) and this option comes handy.
1394 So if you are using bzImage for capturing the crash dump, leave
1395 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1396 Otherwise if you plan to use vmlinux for capturing the crash dump
1397 change this value to start of the reserved region (Typically 16MB
1398 0x1000000). In other words, it can be set based on the "X" value as
1399 specified in the "crashkernel=YM@XM" command line boot parameter
1400 passed to the panic-ed kernel. Typically this parameter is set as
1401 crashkernel=64M@16M. Please take a look at
1402 Documentation/kdump/kdump.txt for more details about crash dumps.
1404 Usage of bzImage for capturing the crash dump is recommended as
1405 one does not have to build two kernels. Same kernel can be used
1406 as production kernel and capture kernel. Above option should have
1407 gone away after relocatable bzImage support is introduced. But it
1408 is present because there are users out there who continue to use
1409 vmlinux for dump capture. This option should go away down the
1412 Don't change this unless you know what you are doing.
1415 bool "Build a relocatable kernel (EXPERIMENTAL)"
1416 depends on EXPERIMENTAL
1418 This builds a kernel image that retains relocation information
1419 so it can be loaded someplace besides the default 1MB.
1420 The relocations tend to make the kernel binary about 10% larger,
1421 but are discarded at runtime.
1423 One use is for the kexec on panic case where the recovery kernel
1424 must live at a different physical address than the primary
1427 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1428 it has been loaded at and the compile time physical address
1429 (CONFIG_PHYSICAL_START) is ignored.
1431 config PHYSICAL_ALIGN
1433 prompt "Alignment value to which kernel should be aligned" if X86_32
1434 default "0x100000" if X86_32
1435 default "0x200000" if X86_64
1436 range 0x2000 0x400000
1438 This value puts the alignment restrictions on physical address
1439 where kernel is loaded and run from. Kernel is compiled for an
1440 address which meets above alignment restriction.
1442 If bootloader loads the kernel at a non-aligned address and
1443 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1444 address aligned to above value and run from there.
1446 If bootloader loads the kernel at a non-aligned address and
1447 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1448 load address and decompress itself to the address it has been
1449 compiled for and run from there. The address for which kernel is
1450 compiled already meets above alignment restrictions. Hence the
1451 end result is that kernel runs from a physical address meeting
1452 above alignment restrictions.
1454 Don't change this unless you know what you are doing.
1457 bool "Support for hot-pluggable CPUs"
1458 depends on SMP && HOTPLUG && !X86_VOYAGER
1460 Say Y here to allow turning CPUs off and on. CPUs can be
1461 controlled through /sys/devices/system/cpu.
1462 ( Note: power management support will enable this option
1463 automatically on SMP systems. )
1464 Say N if you want to disable CPU hotplug.
1468 prompt "Compat VDSO support"
1469 depends on X86_32 || IA32_EMULATION
1471 Map the 32-bit VDSO to the predictable old-style address too.
1473 Say N here if you are running a sufficiently recent glibc
1474 version (2.3.3 or later), to remove the high-mapped
1475 VDSO mapping and to exclusively use the randomized VDSO.
1480 bool "Built-in kernel command line"
1483 Allow for specifying boot arguments to the kernel at
1484 build time. On some systems (e.g. embedded ones), it is
1485 necessary or convenient to provide some or all of the
1486 kernel boot arguments with the kernel itself (that is,
1487 to not rely on the boot loader to provide them.)
1489 To compile command line arguments into the kernel,
1490 set this option to 'Y', then fill in the
1491 the boot arguments in CONFIG_CMDLINE.
1493 Systems with fully functional boot loaders (i.e. non-embedded)
1494 should leave this option set to 'N'.
1497 string "Built-in kernel command string"
1498 depends on CMDLINE_BOOL
1501 Enter arguments here that should be compiled into the kernel
1502 image and used at boot time. If the boot loader provides a
1503 command line at boot time, it is appended to this string to
1504 form the full kernel command line, when the system boots.
1506 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1507 change this behavior.
1509 In most cases, the command line (whether built-in or provided
1510 by the boot loader) should specify the device for the root
1513 config CMDLINE_OVERRIDE
1514 bool "Built-in command line overrides boot loader arguments"
1516 depends on CMDLINE_BOOL
1518 Set this option to 'Y' to have the kernel ignore the boot loader
1519 command line, and use ONLY the built-in command line.
1521 This is used to work around broken boot loaders. This should
1522 be set to 'N' under normal conditions.
1526 config ARCH_ENABLE_MEMORY_HOTPLUG
1528 depends on X86_64 || (X86_32 && HIGHMEM)
1530 config ARCH_ENABLE_MEMORY_HOTREMOVE
1532 depends on MEMORY_HOTPLUG
1534 config HAVE_ARCH_EARLY_PFN_TO_NID
1538 menu "Power management and ACPI options"
1539 depends on !X86_VOYAGER
1541 config ARCH_HIBERNATION_HEADER
1543 depends on X86_64 && HIBERNATION
1545 source "kernel/power/Kconfig"
1547 source "drivers/acpi/Kconfig"
1552 depends on APM || APM_MODULE
1555 tristate "APM (Advanced Power Management) BIOS support"
1556 depends on X86_32 && PM_SLEEP
1558 APM is a BIOS specification for saving power using several different
1559 techniques. This is mostly useful for battery powered laptops with
1560 APM compliant BIOSes. If you say Y here, the system time will be
1561 reset after a RESUME operation, the /proc/apm device will provide
1562 battery status information, and user-space programs will receive
1563 notification of APM "events" (e.g. battery status change).
1565 If you select "Y" here, you can disable actual use of the APM
1566 BIOS by passing the "apm=off" option to the kernel at boot time.
1568 Note that the APM support is almost completely disabled for
1569 machines with more than one CPU.
1571 In order to use APM, you will need supporting software. For location
1572 and more information, read <file:Documentation/power/pm.txt> and the
1573 Battery Powered Linux mini-HOWTO, available from
1574 <http://www.tldp.org/docs.html#howto>.
1576 This driver does not spin down disk drives (see the hdparm(8)
1577 manpage ("man 8 hdparm") for that), and it doesn't turn off
1578 VESA-compliant "green" monitors.
1580 This driver does not support the TI 4000M TravelMate and the ACER
1581 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1582 desktop machines also don't have compliant BIOSes, and this driver
1583 may cause those machines to panic during the boot phase.
1585 Generally, if you don't have a battery in your machine, there isn't
1586 much point in using this driver and you should say N. If you get
1587 random kernel OOPSes or reboots that don't seem to be related to
1588 anything, try disabling/enabling this option (or disabling/enabling
1591 Some other things you should try when experiencing seemingly random,
1594 1) make sure that you have enough swap space and that it is
1596 2) pass the "no-hlt" option to the kernel
1597 3) switch on floating point emulation in the kernel and pass
1598 the "no387" option to the kernel
1599 4) pass the "floppy=nodma" option to the kernel
1600 5) pass the "mem=4M" option to the kernel (thereby disabling
1601 all but the first 4 MB of RAM)
1602 6) make sure that the CPU is not over clocked.
1603 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1604 8) disable the cache from your BIOS settings
1605 9) install a fan for the video card or exchange video RAM
1606 10) install a better fan for the CPU
1607 11) exchange RAM chips
1608 12) exchange the motherboard.
1610 To compile this driver as a module, choose M here: the
1611 module will be called apm.
1615 config APM_IGNORE_USER_SUSPEND
1616 bool "Ignore USER SUSPEND"
1618 This option will ignore USER SUSPEND requests. On machines with a
1619 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1620 series notebooks, it is necessary to say Y because of a BIOS bug.
1622 config APM_DO_ENABLE
1623 bool "Enable PM at boot time"
1625 Enable APM features at boot time. From page 36 of the APM BIOS
1626 specification: "When disabled, the APM BIOS does not automatically
1627 power manage devices, enter the Standby State, enter the Suspend
1628 State, or take power saving steps in response to CPU Idle calls."
1629 This driver will make CPU Idle calls when Linux is idle (unless this
1630 feature is turned off -- see "Do CPU IDLE calls", below). This
1631 should always save battery power, but more complicated APM features
1632 will be dependent on your BIOS implementation. You may need to turn
1633 this option off if your computer hangs at boot time when using APM
1634 support, or if it beeps continuously instead of suspending. Turn
1635 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1636 T400CDT. This is off by default since most machines do fine without
1640 bool "Make CPU Idle calls when idle"
1642 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1643 On some machines, this can activate improved power savings, such as
1644 a slowed CPU clock rate, when the machine is idle. These idle calls
1645 are made after the idle loop has run for some length of time (e.g.,
1646 333 mS). On some machines, this will cause a hang at boot time or
1647 whenever the CPU becomes idle. (On machines with more than one CPU,
1648 this option does nothing.)
1650 config APM_DISPLAY_BLANK
1651 bool "Enable console blanking using APM"
1653 Enable console blanking using the APM. Some laptops can use this to
1654 turn off the LCD backlight when the screen blanker of the Linux
1655 virtual console blanks the screen. Note that this is only used by
1656 the virtual console screen blanker, and won't turn off the backlight
1657 when using the X Window system. This also doesn't have anything to
1658 do with your VESA-compliant power-saving monitor. Further, this
1659 option doesn't work for all laptops -- it might not turn off your
1660 backlight at all, or it might print a lot of errors to the console,
1661 especially if you are using gpm.
1663 config APM_ALLOW_INTS
1664 bool "Allow interrupts during APM BIOS calls"
1666 Normally we disable external interrupts while we are making calls to
1667 the APM BIOS as a measure to lessen the effects of a badly behaving
1668 BIOS implementation. The BIOS should reenable interrupts if it
1669 needs to. Unfortunately, some BIOSes do not -- especially those in
1670 many of the newer IBM Thinkpads. If you experience hangs when you
1671 suspend, try setting this to Y. Otherwise, say N.
1675 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1677 source "drivers/cpuidle/Kconfig"
1679 source "drivers/idle/Kconfig"
1684 menu "Bus options (PCI etc.)"
1689 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1691 Find out whether you have a PCI motherboard. PCI is the name of a
1692 bus system, i.e. the way the CPU talks to the other stuff inside
1693 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1694 VESA. If you have PCI, say Y, otherwise N.
1697 prompt "PCI access mode"
1698 depends on X86_32 && PCI
1701 On PCI systems, the BIOS can be used to detect the PCI devices and
1702 determine their configuration. However, some old PCI motherboards
1703 have BIOS bugs and may crash if this is done. Also, some embedded
1704 PCI-based systems don't have any BIOS at all. Linux can also try to
1705 detect the PCI hardware directly without using the BIOS.
1707 With this option, you can specify how Linux should detect the
1708 PCI devices. If you choose "BIOS", the BIOS will be used,
1709 if you choose "Direct", the BIOS won't be used, and if you
1710 choose "MMConfig", then PCI Express MMCONFIG will be used.
1711 If you choose "Any", the kernel will try MMCONFIG, then the
1712 direct access method and falls back to the BIOS if that doesn't
1713 work. If unsure, go with the default, which is "Any".
1718 config PCI_GOMMCONFIG
1735 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1737 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1740 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1744 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1748 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1755 bool "Support mmconfig PCI config space access"
1756 depends on X86_64 && PCI && ACPI
1759 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1760 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1762 DMA remapping (DMAR) devices support enables independent address
1763 translations for Direct Memory Access (DMA) from devices.
1764 These DMA remapping devices are reported via ACPI tables
1765 and include PCI device scope covered by these DMA
1770 prompt "Support for Graphics workaround"
1773 Current Graphics drivers tend to use physical address
1774 for DMA and avoid using DMA APIs. Setting this config
1775 option permits the IOMMU driver to set a unity map for
1776 all the OS-visible memory. Hence the driver can continue
1777 to use physical addresses for DMA.
1779 config DMAR_FLOPPY_WA
1783 Floppy disk drivers are know to bypass DMA API calls
1784 thereby failing to work when IOMMU is enabled. This
1785 workaround will setup a 1:1 mapping for the first
1786 16M to make floppy (an ISA device) work.
1789 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1790 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1792 Supports Interrupt remapping for IO-APIC and MSI devices.
1793 To use x2apic mode in the CPU's which support x2APIC enhancements or
1794 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1796 source "drivers/pci/pcie/Kconfig"
1798 source "drivers/pci/Kconfig"
1800 # x86_64 have no ISA slots, but do have ISA-style DMA.
1808 depends on !X86_VOYAGER
1810 Find out whether you have ISA slots on your motherboard. ISA is the
1811 name of a bus system, i.e. the way the CPU talks to the other stuff
1812 inside your box. Other bus systems are PCI, EISA, MicroChannel
1813 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1814 newer boards don't support it. If you have ISA, say Y, otherwise N.
1820 The Extended Industry Standard Architecture (EISA) bus was
1821 developed as an open alternative to the IBM MicroChannel bus.
1823 The EISA bus provided some of the features of the IBM MicroChannel
1824 bus while maintaining backward compatibility with cards made for
1825 the older ISA bus. The EISA bus saw limited use between 1988 and
1826 1995 when it was made obsolete by the PCI bus.
1828 Say Y here if you are building a kernel for an EISA-based machine.
1832 source "drivers/eisa/Kconfig"
1835 bool "MCA support" if !X86_VOYAGER
1836 default y if X86_VOYAGER
1838 MicroChannel Architecture is found in some IBM PS/2 machines and
1839 laptops. It is a bus system similar to PCI or ISA. See
1840 <file:Documentation/mca.txt> (and especially the web page given
1841 there) before attempting to build an MCA bus kernel.
1843 source "drivers/mca/Kconfig"
1846 tristate "NatSemi SCx200 support"
1847 depends on !X86_VOYAGER
1849 This provides basic support for National Semiconductor's
1850 (now AMD's) Geode processors. The driver probes for the
1851 PCI-IDs of several on-chip devices, so its a good dependency
1852 for other scx200_* drivers.
1854 If compiled as a module, the driver is named scx200.
1856 config SCx200HR_TIMER
1857 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1858 depends on SCx200 && GENERIC_TIME
1861 This driver provides a clocksource built upon the on-chip
1862 27MHz high-resolution timer. Its also a workaround for
1863 NSC Geode SC-1100's buggy TSC, which loses time when the
1864 processor goes idle (as is done by the scheduler). The
1865 other workaround is idle=poll boot option.
1867 config GEODE_MFGPT_TIMER
1869 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1870 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1872 This driver provides a clock event source based on the MFGPT
1873 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1874 MFGPTs have a better resolution and max interval than the
1875 generic PIT, and are suitable for use as high-res timers.
1878 bool "One Laptop Per Child support"
1881 Add support for detecting the unique features of the OLPC
1888 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1890 source "drivers/pcmcia/Kconfig"
1892 source "drivers/pci/hotplug/Kconfig"
1897 menu "Executable file formats / Emulations"
1899 source "fs/Kconfig.binfmt"
1901 config IA32_EMULATION
1902 bool "IA32 Emulation"
1904 select COMPAT_BINFMT_ELF
1906 Include code to run 32-bit programs under a 64-bit kernel. You should
1907 likely turn this on, unless you're 100% sure that you don't have any
1908 32-bit programs left.
1911 tristate "IA32 a.out support"
1912 depends on IA32_EMULATION
1914 Support old a.out binaries in the 32bit emulation.
1918 depends on IA32_EMULATION
1920 config COMPAT_FOR_U64_ALIGNMENT
1924 config SYSVIPC_COMPAT
1926 depends on COMPAT && SYSVIPC
1931 config HAVE_ATOMIC_IOMAP
1935 source "net/Kconfig"
1937 source "drivers/Kconfig"
1939 source "drivers/firmware/Kconfig"
1943 source "arch/x86/Kconfig.debug"
1945 source "security/Kconfig"
1947 source "crypto/Kconfig"
1949 source "arch/x86/kvm/Kconfig"
1951 source "lib/Kconfig"
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