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_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
35 select HAVE_ARCH_KGDB if !X86_VOYAGER
36 select HAVE_ARCH_TRACEHOOK
37 select HAVE_GENERIC_DMA_COHERENT if X86_32
38 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 default "arch/x86/configs/i386_defconfig" if X86_32
43 default "arch/x86/configs/x86_64_defconfig" if X86_64
48 config GENERIC_CMOS_UPDATE
51 config CLOCKSOURCE_WATCHDOG
54 config GENERIC_CLOCKEVENTS
57 config GENERIC_CLOCKEVENTS_BROADCAST
59 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
61 config LOCKDEP_SUPPORT
64 config STACKTRACE_SUPPORT
67 config HAVE_LATENCYTOP_SUPPORT
70 config FAST_CMPXCHG_LOCAL
83 config GENERIC_ISA_DMA
92 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
94 config GENERIC_BUG_RELATIVE_POINTERS
97 config GENERIC_HWEIGHT
103 config ARCH_MAY_HAVE_PC_FDC
106 config RWSEM_GENERIC_SPINLOCK
109 config RWSEM_XCHGADD_ALGORITHM
112 config ARCH_HAS_CPU_IDLE_WAIT
115 config GENERIC_CALIBRATE_DELAY
118 config GENERIC_TIME_VSYSCALL
122 config ARCH_HAS_CPU_RELAX
125 config ARCH_HAS_DEFAULT_IDLE
128 config ARCH_HAS_CACHE_LINE_SIZE
131 config HAVE_SETUP_PER_CPU_AREA
132 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
134 config HAVE_CPUMASK_OF_CPU_MAP
137 config ARCH_HIBERNATION_POSSIBLE
139 depends on !SMP || !X86_VOYAGER
141 config ARCH_SUSPEND_POSSIBLE
143 depends on !X86_VOYAGER
149 config ARCH_POPULATES_NODE_MAP
156 config ARCH_SUPPORTS_OPTIMIZED_INLINING
159 # Use the generic interrupt handling code in kernel/irq/:
160 config GENERIC_HARDIRQS
164 config GENERIC_IRQ_PROBE
168 config GENERIC_PENDING_IRQ
170 depends on GENERIC_HARDIRQS && SMP
175 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
178 config USE_GENERIC_SMP_HELPERS
184 depends on X86_32 && SMP
188 depends on X86_64 && SMP
193 depends on (X86_32 && !X86_VOYAGER) || X86_64
196 config X86_BIOS_REBOOT
198 depends on !X86_VOYAGER
201 config X86_TRAMPOLINE
203 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
208 source "init/Kconfig"
209 source "kernel/Kconfig.freezer"
211 menu "Processor type and features"
213 source "kernel/time/Kconfig"
216 bool "Symmetric multi-processing support"
218 This enables support for systems with more than one CPU. If you have
219 a system with only one CPU, like most personal computers, say N. If
220 you have a system with more than one CPU, say Y.
222 If you say N here, the kernel will run on single and multiprocessor
223 machines, but will use only one CPU of a multiprocessor machine. If
224 you say Y here, the kernel will run on many, but not all,
225 singleprocessor machines. On a singleprocessor machine, the kernel
226 will run faster if you say N here.
228 Note that if you say Y here and choose architecture "586" or
229 "Pentium" under "Processor family", the kernel will not work on 486
230 architectures. Similarly, multiprocessor kernels for the "PPro"
231 architecture may not work on all Pentium based boards.
233 People using multiprocessor machines who say Y here should also say
234 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
235 Management" code will be disabled if you say Y here.
237 See also <file:Documentation/i386/IO-APIC.txt>,
238 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
239 <http://www.tldp.org/docs.html#howto>.
241 If you don't know what to do here, say N.
243 config X86_HAS_BOOT_CPU_ID
245 depends on X86_VOYAGER
247 config X86_FIND_SMP_CONFIG
249 depends on X86_MPPARSE || X86_VOYAGER
252 bool "Enable MPS table" if ACPI
254 depends on X86_LOCAL_APIC
256 For old smp systems that do not have proper acpi support. Newer systems
257 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
260 prompt "Subarchitecture Type"
266 Choose this option if your computer is a standard PC or compatible.
272 Select this for an AMD Elan processor.
274 Do not use this option for K6/Athlon/Opteron processors!
276 If unsure, choose "PC-compatible" instead.
280 depends on X86_32 && (SMP || BROKEN) && !PCI
282 Voyager is an MCA-based 32-way capable SMP architecture proprietary
283 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
287 If you do not specifically know you have a Voyager based machine,
288 say N here, otherwise the kernel you build will not be bootable.
290 config X86_GENERICARCH
291 bool "Generic architecture"
294 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
295 subarchitectures. It is intended for a generic binary kernel.
296 if you select them all, kernel will probe it one by one. and will
302 bool "NUMAQ (IBM/Sequent)"
303 depends on SMP && X86_32 && PCI && X86_MPPARSE
306 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
307 NUMA multiquad box. This changes the way that processors are
308 bootstrapped, and uses Clustered Logical APIC addressing mode instead
309 of Flat Logical. You will need a new lynxer.elf file to flash your
310 firmware with - send email to <Martin.Bligh@us.ibm.com>.
313 bool "Summit/EXA (IBM x440)"
314 depends on X86_32 && SMP
316 This option is needed for IBM systems that use the Summit/EXA chipset.
317 In particular, it is needed for the x440.
320 bool "Support for Unisys ES7000 IA32 series"
321 depends on X86_32 && SMP
323 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
324 supposed to run on an IA32-based Unisys ES7000 system.
327 bool "Support for big SMP systems with more than 8 CPUs"
328 depends on X86_32 && SMP
330 This option is needed for the systems that have more than 8 CPUs
331 and if the system is not of any sub-arch type above.
336 bool "Support for ScaleMP vSMP"
338 depends on X86_64 && PCI
340 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
341 supposed to run on these EM64T-based machines. Only choose this option
342 if you have one of these machines.
347 bool "SGI 320/540 (Visual Workstation)"
348 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
350 The SGI Visual Workstation series is an IA32-based workstation
351 based on SGI systems chips with some legacy PC hardware attached.
353 Say Y here to create a kernel to run on the SGI 320 or 540.
355 A kernel compiled for the Visual Workstation will run on general
356 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
359 bool "RDC R-321x SoC"
362 select X86_REBOOTFIXUPS
364 This option is needed for RDC R-321x system-on-chip, also known
366 If you don't have one of these chips, you should say N here.
368 config SCHED_NO_NO_OMIT_FRAME_POINTER
370 prompt "Single-depth WCHAN output"
373 Calculate simpler /proc/<PID>/wchan values. If this option
374 is disabled then wchan values will recurse back to the
375 caller function. This provides more accurate wchan values,
376 at the expense of slightly more scheduling overhead.
378 If in doubt, say "Y".
380 menuconfig PARAVIRT_GUEST
381 bool "Paravirtualized guest support"
383 Say Y here to get to see options related to running Linux under
384 various hypervisors. This option alone does not add any kernel code.
386 If you say N, all options in this submenu will be skipped and disabled.
390 source "arch/x86/xen/Kconfig"
393 bool "VMI Guest support"
396 depends on !X86_VOYAGER
398 VMI provides a paravirtualized interface to the VMware ESX server
399 (it could be used by other hypervisors in theory too, but is not
400 at the moment), by linking the kernel to a GPL-ed ROM module
401 provided by the hypervisor.
404 bool "KVM paravirtualized clock"
406 select PARAVIRT_CLOCK
407 depends on !X86_VOYAGER
409 Turning on this option will allow you to run a paravirtualized clock
410 when running over the KVM hypervisor. Instead of relying on a PIT
411 (or probably other) emulation by the underlying device model, the host
412 provides the guest with timing infrastructure such as time of day, and
416 bool "KVM Guest support"
418 depends on !X86_VOYAGER
420 This option enables various optimizations for running under the KVM
423 source "arch/x86/lguest/Kconfig"
426 bool "Enable paravirtualization code"
427 depends on !X86_VOYAGER
429 This changes the kernel so it can modify itself when it is run
430 under a hypervisor, potentially improving performance significantly
431 over full virtualization. However, when run without a hypervisor
432 the kernel is theoretically slower and slightly larger.
434 config PARAVIRT_CLOCK
440 config PARAVIRT_DEBUG
441 bool "paravirt-ops debugging"
442 depends on PARAVIRT && DEBUG_KERNEL
444 Enable to debug paravirt_ops internals. Specifically, BUG if
445 a paravirt_op is missing when it is called.
450 This option adds a kernel parameter 'memtest', which allows memtest
452 memtest=0, mean disabled; -- default
453 memtest=1, mean do 1 test pattern;
455 memtest=4, mean do 4 test patterns.
456 If you are unsure how to answer this question, answer N.
458 config X86_SUMMIT_NUMA
460 depends on X86_32 && NUMA && X86_GENERICARCH
462 config X86_CYCLONE_TIMER
464 depends on X86_GENERICARCH
466 source "arch/x86/Kconfig.cpu"
470 prompt "HPET Timer Support" if X86_32
472 Use the IA-PC HPET (High Precision Event Timer) to manage
473 time in preference to the PIT and RTC, if a HPET is
475 HPET is the next generation timer replacing legacy 8254s.
476 The HPET provides a stable time base on SMP
477 systems, unlike the TSC, but it is more expensive to access,
478 as it is off-chip. You can find the HPET spec at
479 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
481 You can safely choose Y here. However, HPET will only be
482 activated if the platform and the BIOS support this feature.
483 Otherwise the 8254 will be used for timing services.
485 Choose N to continue using the legacy 8254 timer.
487 config HPET_EMULATE_RTC
489 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
491 # Mark as embedded because too many people got it wrong.
492 # The code disables itself when not needed.
495 bool "Enable DMI scanning" if EMBEDDED
497 Enabled scanning of DMI to identify machine quirks. Say Y
498 here unless you have verified that your setup is not
499 affected by entries in the DMI blacklist. Required by PNP
503 bool "GART IOMMU support" if EMBEDDED
507 depends on X86_64 && PCI
509 Support for full DMA access of devices with 32bit memory access only
510 on systems with more than 3GB. This is usually needed for USB,
511 sound, many IDE/SATA chipsets and some other devices.
512 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
513 based hardware IOMMU and a software bounce buffer based IOMMU used
514 on Intel systems and as fallback.
515 The code is only active when needed (enough memory and limited
516 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
520 bool "IBM Calgary IOMMU support"
522 depends on X86_64 && PCI && EXPERIMENTAL
524 Support for hardware IOMMUs in IBM's xSeries x366 and x460
525 systems. Needed to run systems with more than 3GB of memory
526 properly with 32-bit PCI devices that do not support DAC
527 (Double Address Cycle). Calgary also supports bus level
528 isolation, where all DMAs pass through the IOMMU. This
529 prevents them from going anywhere except their intended
530 destination. This catches hard-to-find kernel bugs and
531 mis-behaving drivers and devices that do not use the DMA-API
532 properly to set up their DMA buffers. The IOMMU can be
533 turned off at boot time with the iommu=off parameter.
534 Normally the kernel will make the right choice by itself.
537 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
539 prompt "Should Calgary be enabled by default?"
540 depends on CALGARY_IOMMU
542 Should Calgary be enabled by default? if you choose 'y', Calgary
543 will be used (if it exists). If you choose 'n', Calgary will not be
544 used even if it exists. If you choose 'n' and would like to use
545 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
549 bool "AMD IOMMU support"
552 depends on X86_64 && PCI && ACPI
554 With this option you can enable support for AMD IOMMU hardware in
555 your system. An IOMMU is a hardware component which provides
556 remapping of DMA memory accesses from devices. With an AMD IOMMU you
557 can isolate the the DMA memory of different devices and protect the
558 system from misbehaving device drivers or hardware.
560 You can find out if your system has an AMD IOMMU if you look into
561 your BIOS for an option to enable it or if you have an IVRS ACPI
564 # need this always selected by IOMMU for the VIA workaround
568 Support for software bounce buffers used on x86-64 systems
569 which don't have a hardware IOMMU (e.g. the current generation
570 of Intel's x86-64 CPUs). Using this PCI devices which can only
571 access 32-bits of memory can be used on systems with more than
572 3 GB of memory. If unsure, say Y.
575 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
578 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
579 depends on X86_64 && SMP && BROKEN
582 Configure maximum number of CPUS and NUMA Nodes for this architecture.
586 int "Maximum number of CPUs (2-512)" if !MAXSMP
589 default "4096" if MAXSMP
590 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
593 This allows you to specify the maximum number of CPUs which this
594 kernel will support. The maximum supported value is 512 and the
595 minimum value which makes sense is 2.
597 This is purely to save memory - each supported CPU adds
598 approximately eight kilobytes to the kernel image.
601 bool "SMT (Hyperthreading) scheduler support"
604 SMT scheduler support improves the CPU scheduler's decision making
605 when dealing with Intel Pentium 4 chips with HyperThreading at a
606 cost of slightly increased overhead in some places. If unsure say
611 prompt "Multi-core scheduler support"
614 Multi-core scheduler support improves the CPU scheduler's decision
615 making when dealing with multi-core CPU chips at a cost of slightly
616 increased overhead in some places. If unsure say N here.
618 source "kernel/Kconfig.preempt"
621 bool "Local APIC support on uniprocessors"
622 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
624 A local APIC (Advanced Programmable Interrupt Controller) is an
625 integrated interrupt controller in the CPU. If you have a single-CPU
626 system which has a processor with a local APIC, you can say Y here to
627 enable and use it. If you say Y here even though your machine doesn't
628 have a local APIC, then the kernel will still run with no slowdown at
629 all. The local APIC supports CPU-generated self-interrupts (timer,
630 performance counters), and the NMI watchdog which detects hard
634 bool "IO-APIC support on uniprocessors"
635 depends on X86_UP_APIC
637 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
638 SMP-capable replacement for PC-style interrupt controllers. Most
639 SMP systems and many recent uniprocessor systems have one.
641 If you have a single-CPU system with an IO-APIC, you can say Y here
642 to use it. If you say Y here even though your machine doesn't have
643 an IO-APIC, then the kernel will still run with no slowdown at all.
645 config X86_LOCAL_APIC
647 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
651 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
653 config X86_VISWS_APIC
655 depends on X86_32 && X86_VISWS
657 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
658 bool "Reroute for broken boot IRQs"
660 depends on X86_IO_APIC
662 This option enables a workaround that fixes a source of
663 spurious interrupts. This is recommended when threaded
664 interrupt handling is used on systems where the generation of
665 superfluous "boot interrupts" cannot be disabled.
667 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
668 entry in the chipset's IO-APIC is masked (as, e.g. the RT
669 kernel does during interrupt handling). On chipsets where this
670 boot IRQ generation cannot be disabled, this workaround keeps
671 the original IRQ line masked so that only the equivalent "boot
672 IRQ" is delivered to the CPUs. The workaround also tells the
673 kernel to set up the IRQ handler on the boot IRQ line. In this
674 way only one interrupt is delivered to the kernel. Otherwise
675 the spurious second interrupt may cause the kernel to bring
676 down (vital) interrupt lines.
678 Only affects "broken" chipsets. Interrupt sharing may be
679 increased on these systems.
682 bool "Machine Check Exception"
683 depends on !X86_VOYAGER
685 Machine Check Exception support allows the processor to notify the
686 kernel if it detects a problem (e.g. overheating, component failure).
687 The action the kernel takes depends on the severity of the problem,
688 ranging from a warning message on the console, to halting the machine.
689 Your processor must be a Pentium or newer to support this - check the
690 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
691 have a design flaw which leads to false MCE events - hence MCE is
692 disabled on all P5 processors, unless explicitly enabled with "mce"
693 as a boot argument. Similarly, if MCE is built in and creates a
694 problem on some new non-standard machine, you can boot with "nomce"
695 to disable it. MCE support simply ignores non-MCE processors like
696 the 386 and 486, so nearly everyone can say Y here.
700 prompt "Intel MCE features"
701 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
703 Additional support for intel specific MCE features such as
708 prompt "AMD MCE features"
709 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
711 Additional support for AMD specific MCE features such as
712 the DRAM Error Threshold.
714 config X86_MCE_NONFATAL
715 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
716 depends on X86_32 && X86_MCE
718 Enabling this feature starts a timer that triggers every 5 seconds which
719 will look at the machine check registers to see if anything happened.
720 Non-fatal problems automatically get corrected (but still logged).
721 Disable this if you don't want to see these messages.
722 Seeing the messages this option prints out may be indicative of dying
723 or out-of-spec (ie, overclocked) hardware.
724 This option only does something on certain CPUs.
725 (AMD Athlon/Duron and Intel Pentium 4)
727 config X86_MCE_P4THERMAL
728 bool "check for P4 thermal throttling interrupt."
729 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
731 Enabling this feature will cause a message to be printed when the P4
732 enters thermal throttling.
735 bool "Enable VM86 support" if EMBEDDED
739 This option is required by programs like DOSEMU to run 16-bit legacy
740 code on X86 processors. It also may be needed by software like
741 XFree86 to initialize some video cards via BIOS. Disabling this
742 option saves about 6k.
745 tristate "Toshiba Laptop support"
748 This adds a driver to safely access the System Management Mode of
749 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
750 not work on models with a Phoenix BIOS. The System Management Mode
751 is used to set the BIOS and power saving options on Toshiba portables.
753 For information on utilities to make use of this driver see the
754 Toshiba Linux utilities web site at:
755 <http://www.buzzard.org.uk/toshiba/>.
757 Say Y if you intend to run this kernel on a Toshiba portable.
761 tristate "Dell laptop support"
763 This adds a driver to safely access the System Management Mode
764 of the CPU on the Dell Inspiron 8000. The System Management Mode
765 is used to read cpu temperature and cooling fan status and to
766 control the fans on the I8K portables.
768 This driver has been tested only on the Inspiron 8000 but it may
769 also work with other Dell laptops. You can force loading on other
770 models by passing the parameter `force=1' to the module. Use at
773 For information on utilities to make use of this driver see the
774 I8K Linux utilities web site at:
775 <http://people.debian.org/~dz/i8k/>
777 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
780 config X86_REBOOTFIXUPS
781 bool "Enable X86 board specific fixups for reboot"
784 This enables chipset and/or board specific fixups to be done
785 in order to get reboot to work correctly. This is only needed on
786 some combinations of hardware and BIOS. The symptom, for which
787 this config is intended, is when reboot ends with a stalled/hung
790 Currently, the only fixup is for the Geode machines using
791 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
793 Say Y if you want to enable the fixup. Currently, it's safe to
794 enable this option even if you don't need it.
798 tristate "/dev/cpu/microcode - microcode support"
801 If you say Y here, you will be able to update the microcode on
802 certain Intel and AMD processors. The Intel support is for the
803 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
804 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
805 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
806 You will obviously need the actual microcode binary data itself
807 which is not shipped with the Linux kernel.
809 This option selects the general module only, you need to select
810 at least one vendor specific module as well.
812 To compile this driver as a module, choose M here: the
813 module will be called microcode.
815 config MICROCODE_INTEL
816 bool "Intel microcode patch loading support"
821 This options enables microcode patch loading support for Intel
824 For latest news and information on obtaining all the required
825 Intel ingredients for this driver, check:
826 <http://www.urbanmyth.org/microcode/>.
829 bool "AMD microcode patch loading support"
833 If you select this option, microcode patch loading support for AMD
834 processors will be enabled.
836 config MICROCODE_OLD_INTERFACE
841 tristate "/dev/cpu/*/msr - Model-specific register support"
843 This device gives privileged processes access to the x86
844 Model-Specific Registers (MSRs). It is a character device with
845 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
846 MSR accesses are directed to a specific CPU on multi-processor
850 tristate "/dev/cpu/*/cpuid - CPU information support"
852 This device gives processes access to the x86 CPUID instruction to
853 be executed on a specific processor. It is a character device
854 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
858 prompt "High Memory Support"
859 default HIGHMEM4G if !X86_NUMAQ
860 default HIGHMEM64G if X86_NUMAQ
865 depends on !X86_NUMAQ
867 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
868 However, the address space of 32-bit x86 processors is only 4
869 Gigabytes large. That means that, if you have a large amount of
870 physical memory, not all of it can be "permanently mapped" by the
871 kernel. The physical memory that's not permanently mapped is called
874 If you are compiling a kernel which will never run on a machine with
875 more than 1 Gigabyte total physical RAM, answer "off" here (default
876 choice and suitable for most users). This will result in a "3GB/1GB"
877 split: 3GB are mapped so that each process sees a 3GB virtual memory
878 space and the remaining part of the 4GB virtual memory space is used
879 by the kernel to permanently map as much physical memory as
882 If the machine has between 1 and 4 Gigabytes physical RAM, then
885 If more than 4 Gigabytes is used then answer "64GB" here. This
886 selection turns Intel PAE (Physical Address Extension) mode on.
887 PAE implements 3-level paging on IA32 processors. PAE is fully
888 supported by Linux, PAE mode is implemented on all recent Intel
889 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
890 then the kernel will not boot on CPUs that don't support PAE!
892 The actual amount of total physical memory will either be
893 auto detected or can be forced by using a kernel command line option
894 such as "mem=256M". (Try "man bootparam" or see the documentation of
895 your boot loader (lilo or loadlin) about how to pass options to the
896 kernel at boot time.)
898 If unsure, say "off".
902 depends on !X86_NUMAQ
904 Select this if you have a 32-bit processor and between 1 and 4
905 gigabytes of physical RAM.
909 depends on !M386 && !M486
912 Select this if you have a 32-bit processor and more than 4
913 gigabytes of physical RAM.
918 depends on EXPERIMENTAL
919 prompt "Memory split" if EMBEDDED
923 Select the desired split between kernel and user memory.
925 If the address range available to the kernel is less than the
926 physical memory installed, the remaining memory will be available
927 as "high memory". Accessing high memory is a little more costly
928 than low memory, as it needs to be mapped into the kernel first.
929 Note that increasing the kernel address space limits the range
930 available to user programs, making the address space there
931 tighter. Selecting anything other than the default 3G/1G split
932 will also likely make your kernel incompatible with binary-only
935 If you are not absolutely sure what you are doing, leave this
939 bool "3G/1G user/kernel split"
940 config VMSPLIT_3G_OPT
942 bool "3G/1G user/kernel split (for full 1G low memory)"
944 bool "2G/2G user/kernel split"
945 config VMSPLIT_2G_OPT
947 bool "2G/2G user/kernel split (for full 2G low memory)"
949 bool "1G/3G user/kernel split"
954 default 0xB0000000 if VMSPLIT_3G_OPT
955 default 0x80000000 if VMSPLIT_2G
956 default 0x78000000 if VMSPLIT_2G_OPT
957 default 0x40000000 if VMSPLIT_1G
963 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
966 bool "PAE (Physical Address Extension) Support"
967 depends on X86_32 && !HIGHMEM4G
969 PAE is required for NX support, and furthermore enables
970 larger swapspace support for non-overcommit purposes. It
971 has the cost of more pagetable lookup overhead, and also
972 consumes more pagetable space per process.
974 config ARCH_PHYS_ADDR_T_64BIT
975 def_bool X86_64 || X86_PAE
977 config DIRECT_GBPAGES
978 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
982 Allow the kernel linear mapping to use 1GB pages on CPUs that
983 support it. This can improve the kernel's performance a tiny bit by
984 reducing TLB pressure. If in doubt, say "Y".
986 # Common NUMA Features
988 bool "Numa Memory Allocation and Scheduler Support"
990 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
992 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
994 Enable NUMA (Non Uniform Memory Access) support.
996 The kernel will try to allocate memory used by a CPU on the
997 local memory controller of the CPU and add some more
998 NUMA awareness to the kernel.
1000 For 64-bit this is recommended if the system is Intel Core i7
1001 (or later), AMD Opteron, or EM64T NUMA.
1003 For 32-bit this is only needed on (rare) 32-bit-only platforms
1004 that support NUMA topologies, such as NUMAQ / Summit, or if you
1005 boot a 32-bit kernel on a 64-bit NUMA platform.
1007 Otherwise, you should say N.
1009 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1010 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1014 prompt "Old style AMD Opteron NUMA detection"
1015 depends on X86_64 && NUMA && PCI
1017 Enable K8 NUMA node topology detection. You should say Y here if
1018 you have a multi processor AMD K8 system. This uses an old
1019 method to read the NUMA configuration directly from the builtin
1020 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1021 instead, which also takes priority if both are compiled in.
1023 config X86_64_ACPI_NUMA
1025 prompt "ACPI NUMA detection"
1026 depends on X86_64 && NUMA && ACPI && PCI
1029 Enable ACPI SRAT based node topology detection.
1031 # Some NUMA nodes have memory ranges that span
1032 # other nodes. Even though a pfn is valid and
1033 # between a node's start and end pfns, it may not
1034 # reside on that node. See memmap_init_zone()
1036 config NODES_SPAN_OTHER_NODES
1038 depends on X86_64_ACPI_NUMA
1041 bool "NUMA emulation"
1042 depends on X86_64 && NUMA
1044 Enable NUMA emulation. A flat machine will be split
1045 into virtual nodes when booted with "numa=fake=N", where N is the
1046 number of nodes. This is only useful for debugging.
1049 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1051 default "9" if MAXSMP
1052 default "6" if X86_64
1053 default "4" if X86_NUMAQ
1055 depends on NEED_MULTIPLE_NODES
1057 Specify the maximum number of NUMA Nodes available on the target
1058 system. Increases memory reserved to accomodate various tables.
1060 config HAVE_ARCH_BOOTMEM_NODE
1062 depends on X86_32 && NUMA
1064 config ARCH_HAVE_MEMORY_PRESENT
1066 depends on X86_32 && DISCONTIGMEM
1068 config NEED_NODE_MEMMAP_SIZE
1070 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1072 config HAVE_ARCH_ALLOC_REMAP
1074 depends on X86_32 && NUMA
1076 config ARCH_FLATMEM_ENABLE
1078 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1080 config ARCH_DISCONTIGMEM_ENABLE
1082 depends on NUMA && X86_32
1084 config ARCH_DISCONTIGMEM_DEFAULT
1086 depends on NUMA && X86_32
1088 config ARCH_SPARSEMEM_DEFAULT
1092 config ARCH_SPARSEMEM_ENABLE
1094 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1095 select SPARSEMEM_STATIC if X86_32
1096 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1098 config ARCH_SELECT_MEMORY_MODEL
1100 depends on ARCH_SPARSEMEM_ENABLE
1102 config ARCH_MEMORY_PROBE
1104 depends on MEMORY_HOTPLUG
1109 bool "Allocate 3rd-level pagetables from highmem"
1110 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1112 The VM uses one page table entry for each page of physical memory.
1113 For systems with a lot of RAM, this can be wasteful of precious
1114 low memory. Setting this option will put user-space page table
1115 entries in high memory.
1117 config X86_CHECK_BIOS_CORRUPTION
1118 bool "Check for low memory corruption"
1120 Periodically check for memory corruption in low memory, which
1121 is suspected to be caused by BIOS. Even when enabled in the
1122 configuration, it is disabled at runtime. Enable it by
1123 setting "memory_corruption_check=1" on the kernel command
1124 line. By default it scans the low 64k of memory every 60
1125 seconds; see the memory_corruption_check_size and
1126 memory_corruption_check_period parameters in
1127 Documentation/kernel-parameters.txt to adjust this.
1129 When enabled with the default parameters, this option has
1130 almost no overhead, as it reserves a relatively small amount
1131 of memory and scans it infrequently. It both detects corruption
1132 and prevents it from affecting the running system.
1134 It is, however, intended as a diagnostic tool; if repeatable
1135 BIOS-originated corruption always affects the same memory,
1136 you can use memmap= to prevent the kernel from using that
1139 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1140 bool "Set the default setting of memory_corruption_check"
1141 depends on X86_CHECK_BIOS_CORRUPTION
1144 Set whether the default state of memory_corruption_check is
1147 config X86_RESERVE_LOW_64K
1148 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1151 Reserve the first 64K of physical RAM on BIOSes that are known
1152 to potentially corrupt that memory range. A numbers of BIOSes are
1153 known to utilize this area during suspend/resume, so it must not
1154 be used by the kernel.
1156 Set this to N if you are absolutely sure that you trust the BIOS
1157 to get all its memory reservations and usages right.
1159 If you have doubts about the BIOS (e.g. suspend/resume does not
1160 work or there's kernel crashes after certain hardware hotplug
1161 events) and it's not AMI or Phoenix, then you might want to enable
1162 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1163 corruption patterns.
1167 config MATH_EMULATION
1169 prompt "Math emulation" if X86_32
1171 Linux can emulate a math coprocessor (used for floating point
1172 operations) if you don't have one. 486DX and Pentium processors have
1173 a math coprocessor built in, 486SX and 386 do not, unless you added
1174 a 487DX or 387, respectively. (The messages during boot time can
1175 give you some hints here ["man dmesg"].) Everyone needs either a
1176 coprocessor or this emulation.
1178 If you don't have a math coprocessor, you need to say Y here; if you
1179 say Y here even though you have a coprocessor, the coprocessor will
1180 be used nevertheless. (This behavior can be changed with the kernel
1181 command line option "no387", which comes handy if your coprocessor
1182 is broken. Try "man bootparam" or see the documentation of your boot
1183 loader (lilo or loadlin) about how to pass options to the kernel at
1184 boot time.) This means that it is a good idea to say Y here if you
1185 intend to use this kernel on different machines.
1187 More information about the internals of the Linux math coprocessor
1188 emulation can be found in <file:arch/x86/math-emu/README>.
1190 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1191 kernel, it won't hurt.
1194 bool "MTRR (Memory Type Range Register) support"
1196 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1197 the Memory Type Range Registers (MTRRs) may be used to control
1198 processor access to memory ranges. This is most useful if you have
1199 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1200 allows bus write transfers to be combined into a larger transfer
1201 before bursting over the PCI/AGP bus. This can increase performance
1202 of image write operations 2.5 times or more. Saying Y here creates a
1203 /proc/mtrr file which may be used to manipulate your processor's
1204 MTRRs. Typically the X server should use this.
1206 This code has a reasonably generic interface so that similar
1207 control registers on other processors can be easily supported
1210 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1211 Registers (ARRs) which provide a similar functionality to MTRRs. For
1212 these, the ARRs are used to emulate the MTRRs.
1213 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1214 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1215 write-combining. All of these processors are supported by this code
1216 and it makes sense to say Y here if you have one of them.
1218 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1219 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1220 can lead to all sorts of problems, so it's good to say Y here.
1222 You can safely say Y even if your machine doesn't have MTRRs, you'll
1223 just add about 9 KB to your kernel.
1225 See <file:Documentation/x86/mtrr.txt> for more information.
1227 config MTRR_SANITIZER
1229 prompt "MTRR cleanup support"
1232 Convert MTRR layout from continuous to discrete, so X drivers can
1233 add writeback entries.
1235 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1236 The largest mtrr entry size for a continous block can be set with
1241 config MTRR_SANITIZER_ENABLE_DEFAULT
1242 int "MTRR cleanup enable value (0-1)"
1245 depends on MTRR_SANITIZER
1247 Enable mtrr cleanup default value
1249 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1250 int "MTRR cleanup spare reg num (0-7)"
1253 depends on MTRR_SANITIZER
1255 mtrr cleanup spare entries default, it can be changed via
1256 mtrr_spare_reg_nr=N on the kernel command line.
1260 prompt "x86 PAT support"
1263 Use PAT attributes to setup page level cache control.
1265 PATs are the modern equivalents of MTRRs and are much more
1266 flexible than MTRRs.
1268 Say N here if you see bootup problems (boot crash, boot hang,
1269 spontaneous reboots) or a non-working video driver.
1274 bool "EFI runtime service support"
1277 This enables the kernel to use EFI runtime services that are
1278 available (such as the EFI variable services).
1280 This option is only useful on systems that have EFI firmware.
1281 In addition, you should use the latest ELILO loader available
1282 at <http://elilo.sourceforge.net> in order to take advantage
1283 of EFI runtime services. However, even with this option, the
1284 resultant kernel should continue to boot on existing non-EFI
1289 prompt "Enable seccomp to safely compute untrusted bytecode"
1291 This kernel feature is useful for number crunching applications
1292 that may need to compute untrusted bytecode during their
1293 execution. By using pipes or other transports made available to
1294 the process as file descriptors supporting the read/write
1295 syscalls, it's possible to isolate those applications in
1296 their own address space using seccomp. Once seccomp is
1297 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1298 and the task is only allowed to execute a few safe syscalls
1299 defined by each seccomp mode.
1301 If unsure, say Y. Only embedded should say N here.
1303 config CC_STACKPROTECTOR
1304 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1305 depends on X86_64 && EXPERIMENTAL && BROKEN
1307 This option turns on the -fstack-protector GCC feature. This
1308 feature puts, at the beginning of critical functions, a canary
1309 value on the stack just before the return address, and validates
1310 the value just before actually returning. Stack based buffer
1311 overflows (that need to overwrite this return address) now also
1312 overwrite the canary, which gets detected and the attack is then
1313 neutralized via a kernel panic.
1315 This feature requires gcc version 4.2 or above, or a distribution
1316 gcc with the feature backported. Older versions are automatically
1317 detected and for those versions, this configuration option is ignored.
1319 config CC_STACKPROTECTOR_ALL
1320 bool "Use stack-protector for all functions"
1321 depends on CC_STACKPROTECTOR
1323 Normally, GCC only inserts the canary value protection for
1324 functions that use large-ish on-stack buffers. By enabling
1325 this option, GCC will be asked to do this for ALL functions.
1327 source kernel/Kconfig.hz
1330 bool "kexec system call"
1331 depends on X86_BIOS_REBOOT
1333 kexec is a system call that implements the ability to shutdown your
1334 current kernel, and to start another kernel. It is like a reboot
1335 but it is independent of the system firmware. And like a reboot
1336 you can start any kernel with it, not just Linux.
1338 The name comes from the similarity to the exec system call.
1340 It is an ongoing process to be certain the hardware in a machine
1341 is properly shutdown, so do not be surprised if this code does not
1342 initially work for you. It may help to enable device hotplugging
1343 support. As of this writing the exact hardware interface is
1344 strongly in flux, so no good recommendation can be made.
1347 bool "kernel crash dumps"
1348 depends on X86_64 || (X86_32 && HIGHMEM)
1350 Generate crash dump after being started by kexec.
1351 This should be normally only set in special crash dump kernels
1352 which are loaded in the main kernel with kexec-tools into
1353 a specially reserved region and then later executed after
1354 a crash by kdump/kexec. The crash dump kernel must be compiled
1355 to a memory address not used by the main kernel or BIOS using
1356 PHYSICAL_START, or it must be built as a relocatable image
1357 (CONFIG_RELOCATABLE=y).
1358 For more details see Documentation/kdump/kdump.txt
1361 bool "kexec jump (EXPERIMENTAL)"
1362 depends on EXPERIMENTAL
1363 depends on KEXEC && HIBERNATION && X86_32
1365 Jump between original kernel and kexeced kernel and invoke
1366 code in physical address mode via KEXEC
1368 config PHYSICAL_START
1369 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1370 default "0x1000000" if X86_NUMAQ
1371 default "0x200000" if X86_64
1374 This gives the physical address where the kernel is loaded.
1376 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1377 bzImage will decompress itself to above physical address and
1378 run from there. Otherwise, bzImage will run from the address where
1379 it has been loaded by the boot loader and will ignore above physical
1382 In normal kdump cases one does not have to set/change this option
1383 as now bzImage can be compiled as a completely relocatable image
1384 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1385 address. This option is mainly useful for the folks who don't want
1386 to use a bzImage for capturing the crash dump and want to use a
1387 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1388 to be specifically compiled to run from a specific memory area
1389 (normally a reserved region) and this option comes handy.
1391 So if you are using bzImage for capturing the crash dump, leave
1392 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1393 Otherwise if you plan to use vmlinux for capturing the crash dump
1394 change this value to start of the reserved region (Typically 16MB
1395 0x1000000). In other words, it can be set based on the "X" value as
1396 specified in the "crashkernel=YM@XM" command line boot parameter
1397 passed to the panic-ed kernel. Typically this parameter is set as
1398 crashkernel=64M@16M. Please take a look at
1399 Documentation/kdump/kdump.txt for more details about crash dumps.
1401 Usage of bzImage for capturing the crash dump is recommended as
1402 one does not have to build two kernels. Same kernel can be used
1403 as production kernel and capture kernel. Above option should have
1404 gone away after relocatable bzImage support is introduced. But it
1405 is present because there are users out there who continue to use
1406 vmlinux for dump capture. This option should go away down the
1409 Don't change this unless you know what you are doing.
1412 bool "Build a relocatable kernel (EXPERIMENTAL)"
1413 depends on EXPERIMENTAL
1415 This builds a kernel image that retains relocation information
1416 so it can be loaded someplace besides the default 1MB.
1417 The relocations tend to make the kernel binary about 10% larger,
1418 but are discarded at runtime.
1420 One use is for the kexec on panic case where the recovery kernel
1421 must live at a different physical address than the primary
1424 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1425 it has been loaded at and the compile time physical address
1426 (CONFIG_PHYSICAL_START) is ignored.
1428 config PHYSICAL_ALIGN
1430 prompt "Alignment value to which kernel should be aligned" if X86_32
1431 default "0x100000" if X86_32
1432 default "0x200000" if X86_64
1433 range 0x2000 0x400000
1435 This value puts the alignment restrictions on physical address
1436 where kernel is loaded and run from. Kernel is compiled for an
1437 address which meets above alignment restriction.
1439 If bootloader loads the kernel at a non-aligned address and
1440 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1441 address aligned to above value and run from there.
1443 If bootloader loads the kernel at a non-aligned address and
1444 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1445 load address and decompress itself to the address it has been
1446 compiled for and run from there. The address for which kernel is
1447 compiled already meets above alignment restrictions. Hence the
1448 end result is that kernel runs from a physical address meeting
1449 above alignment restrictions.
1451 Don't change this unless you know what you are doing.
1454 bool "Support for hot-pluggable CPUs"
1455 depends on SMP && HOTPLUG && !X86_VOYAGER
1457 Say Y here to allow turning CPUs off and on. CPUs can be
1458 controlled through /sys/devices/system/cpu.
1459 ( Note: power management support will enable this option
1460 automatically on SMP systems. )
1461 Say N if you want to disable CPU hotplug.
1465 prompt "Compat VDSO support"
1466 depends on X86_32 || IA32_EMULATION
1468 Map the 32-bit VDSO to the predictable old-style address too.
1470 Say N here if you are running a sufficiently recent glibc
1471 version (2.3.3 or later), to remove the high-mapped
1472 VDSO mapping and to exclusively use the randomized VDSO.
1477 bool "Built-in kernel command line"
1480 Allow for specifying boot arguments to the kernel at
1481 build time. On some systems (e.g. embedded ones), it is
1482 necessary or convenient to provide some or all of the
1483 kernel boot arguments with the kernel itself (that is,
1484 to not rely on the boot loader to provide them.)
1486 To compile command line arguments into the kernel,
1487 set this option to 'Y', then fill in the
1488 the boot arguments in CONFIG_CMDLINE.
1490 Systems with fully functional boot loaders (i.e. non-embedded)
1491 should leave this option set to 'N'.
1494 string "Built-in kernel command string"
1495 depends on CMDLINE_BOOL
1498 Enter arguments here that should be compiled into the kernel
1499 image and used at boot time. If the boot loader provides a
1500 command line at boot time, it is appended to this string to
1501 form the full kernel command line, when the system boots.
1503 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1504 change this behavior.
1506 In most cases, the command line (whether built-in or provided
1507 by the boot loader) should specify the device for the root
1510 config CMDLINE_OVERRIDE
1511 bool "Built-in command line overrides boot loader arguments"
1513 depends on CMDLINE_BOOL
1515 Set this option to 'Y' to have the kernel ignore the boot loader
1516 command line, and use ONLY the built-in command line.
1518 This is used to work around broken boot loaders. This should
1519 be set to 'N' under normal conditions.
1523 config ARCH_ENABLE_MEMORY_HOTPLUG
1525 depends on X86_64 || (X86_32 && HIGHMEM)
1527 config ARCH_ENABLE_MEMORY_HOTREMOVE
1529 depends on MEMORY_HOTPLUG
1531 config HAVE_ARCH_EARLY_PFN_TO_NID
1535 menu "Power management and ACPI options"
1536 depends on !X86_VOYAGER
1538 config ARCH_HIBERNATION_HEADER
1540 depends on X86_64 && HIBERNATION
1542 source "kernel/power/Kconfig"
1544 source "drivers/acpi/Kconfig"
1549 depends on APM || APM_MODULE
1552 tristate "APM (Advanced Power Management) BIOS support"
1553 depends on X86_32 && PM_SLEEP
1555 APM is a BIOS specification for saving power using several different
1556 techniques. This is mostly useful for battery powered laptops with
1557 APM compliant BIOSes. If you say Y here, the system time will be
1558 reset after a RESUME operation, the /proc/apm device will provide
1559 battery status information, and user-space programs will receive
1560 notification of APM "events" (e.g. battery status change).
1562 If you select "Y" here, you can disable actual use of the APM
1563 BIOS by passing the "apm=off" option to the kernel at boot time.
1565 Note that the APM support is almost completely disabled for
1566 machines with more than one CPU.
1568 In order to use APM, you will need supporting software. For location
1569 and more information, read <file:Documentation/power/pm.txt> and the
1570 Battery Powered Linux mini-HOWTO, available from
1571 <http://www.tldp.org/docs.html#howto>.
1573 This driver does not spin down disk drives (see the hdparm(8)
1574 manpage ("man 8 hdparm") for that), and it doesn't turn off
1575 VESA-compliant "green" monitors.
1577 This driver does not support the TI 4000M TravelMate and the ACER
1578 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1579 desktop machines also don't have compliant BIOSes, and this driver
1580 may cause those machines to panic during the boot phase.
1582 Generally, if you don't have a battery in your machine, there isn't
1583 much point in using this driver and you should say N. If you get
1584 random kernel OOPSes or reboots that don't seem to be related to
1585 anything, try disabling/enabling this option (or disabling/enabling
1588 Some other things you should try when experiencing seemingly random,
1591 1) make sure that you have enough swap space and that it is
1593 2) pass the "no-hlt" option to the kernel
1594 3) switch on floating point emulation in the kernel and pass
1595 the "no387" option to the kernel
1596 4) pass the "floppy=nodma" option to the kernel
1597 5) pass the "mem=4M" option to the kernel (thereby disabling
1598 all but the first 4 MB of RAM)
1599 6) make sure that the CPU is not over clocked.
1600 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1601 8) disable the cache from your BIOS settings
1602 9) install a fan for the video card or exchange video RAM
1603 10) install a better fan for the CPU
1604 11) exchange RAM chips
1605 12) exchange the motherboard.
1607 To compile this driver as a module, choose M here: the
1608 module will be called apm.
1612 config APM_IGNORE_USER_SUSPEND
1613 bool "Ignore USER SUSPEND"
1615 This option will ignore USER SUSPEND requests. On machines with a
1616 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1617 series notebooks, it is necessary to say Y because of a BIOS bug.
1619 config APM_DO_ENABLE
1620 bool "Enable PM at boot time"
1622 Enable APM features at boot time. From page 36 of the APM BIOS
1623 specification: "When disabled, the APM BIOS does not automatically
1624 power manage devices, enter the Standby State, enter the Suspend
1625 State, or take power saving steps in response to CPU Idle calls."
1626 This driver will make CPU Idle calls when Linux is idle (unless this
1627 feature is turned off -- see "Do CPU IDLE calls", below). This
1628 should always save battery power, but more complicated APM features
1629 will be dependent on your BIOS implementation. You may need to turn
1630 this option off if your computer hangs at boot time when using APM
1631 support, or if it beeps continuously instead of suspending. Turn
1632 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1633 T400CDT. This is off by default since most machines do fine without
1637 bool "Make CPU Idle calls when idle"
1639 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1640 On some machines, this can activate improved power savings, such as
1641 a slowed CPU clock rate, when the machine is idle. These idle calls
1642 are made after the idle loop has run for some length of time (e.g.,
1643 333 mS). On some machines, this will cause a hang at boot time or
1644 whenever the CPU becomes idle. (On machines with more than one CPU,
1645 this option does nothing.)
1647 config APM_DISPLAY_BLANK
1648 bool "Enable console blanking using APM"
1650 Enable console blanking using the APM. Some laptops can use this to
1651 turn off the LCD backlight when the screen blanker of the Linux
1652 virtual console blanks the screen. Note that this is only used by
1653 the virtual console screen blanker, and won't turn off the backlight
1654 when using the X Window system. This also doesn't have anything to
1655 do with your VESA-compliant power-saving monitor. Further, this
1656 option doesn't work for all laptops -- it might not turn off your
1657 backlight at all, or it might print a lot of errors to the console,
1658 especially if you are using gpm.
1660 config APM_ALLOW_INTS
1661 bool "Allow interrupts during APM BIOS calls"
1663 Normally we disable external interrupts while we are making calls to
1664 the APM BIOS as a measure to lessen the effects of a badly behaving
1665 BIOS implementation. The BIOS should reenable interrupts if it
1666 needs to. Unfortunately, some BIOSes do not -- especially those in
1667 many of the newer IBM Thinkpads. If you experience hangs when you
1668 suspend, try setting this to Y. Otherwise, say N.
1672 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1674 source "drivers/cpuidle/Kconfig"
1676 source "drivers/idle/Kconfig"
1681 menu "Bus options (PCI etc.)"
1686 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1688 Find out whether you have a PCI motherboard. PCI is the name of a
1689 bus system, i.e. the way the CPU talks to the other stuff inside
1690 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1691 VESA. If you have PCI, say Y, otherwise N.
1694 prompt "PCI access mode"
1695 depends on X86_32 && PCI
1698 On PCI systems, the BIOS can be used to detect the PCI devices and
1699 determine their configuration. However, some old PCI motherboards
1700 have BIOS bugs and may crash if this is done. Also, some embedded
1701 PCI-based systems don't have any BIOS at all. Linux can also try to
1702 detect the PCI hardware directly without using the BIOS.
1704 With this option, you can specify how Linux should detect the
1705 PCI devices. If you choose "BIOS", the BIOS will be used,
1706 if you choose "Direct", the BIOS won't be used, and if you
1707 choose "MMConfig", then PCI Express MMCONFIG will be used.
1708 If you choose "Any", the kernel will try MMCONFIG, then the
1709 direct access method and falls back to the BIOS if that doesn't
1710 work. If unsure, go with the default, which is "Any".
1715 config PCI_GOMMCONFIG
1732 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1734 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1737 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1741 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1745 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1752 bool "Support mmconfig PCI config space access"
1753 depends on X86_64 && PCI && ACPI
1756 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1757 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1759 DMA remapping (DMAR) devices support enables independent address
1760 translations for Direct Memory Access (DMA) from devices.
1761 These DMA remapping devices are reported via ACPI tables
1762 and include PCI device scope covered by these DMA
1767 prompt "Support for Graphics workaround"
1770 Current Graphics drivers tend to use physical address
1771 for DMA and avoid using DMA APIs. Setting this config
1772 option permits the IOMMU driver to set a unity map for
1773 all the OS-visible memory. Hence the driver can continue
1774 to use physical addresses for DMA.
1776 config DMAR_FLOPPY_WA
1780 Floppy disk drivers are know to bypass DMA API calls
1781 thereby failing to work when IOMMU is enabled. This
1782 workaround will setup a 1:1 mapping for the first
1783 16M to make floppy (an ISA device) work.
1786 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1787 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1789 Supports Interrupt remapping for IO-APIC and MSI devices.
1790 To use x2apic mode in the CPU's which support x2APIC enhancements or
1791 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1793 source "drivers/pci/pcie/Kconfig"
1795 source "drivers/pci/Kconfig"
1797 # x86_64 have no ISA slots, but do have ISA-style DMA.
1805 depends on !X86_VOYAGER
1807 Find out whether you have ISA slots on your motherboard. ISA is the
1808 name of a bus system, i.e. the way the CPU talks to the other stuff
1809 inside your box. Other bus systems are PCI, EISA, MicroChannel
1810 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1811 newer boards don't support it. If you have ISA, say Y, otherwise N.
1817 The Extended Industry Standard Architecture (EISA) bus was
1818 developed as an open alternative to the IBM MicroChannel bus.
1820 The EISA bus provided some of the features of the IBM MicroChannel
1821 bus while maintaining backward compatibility with cards made for
1822 the older ISA bus. The EISA bus saw limited use between 1988 and
1823 1995 when it was made obsolete by the PCI bus.
1825 Say Y here if you are building a kernel for an EISA-based machine.
1829 source "drivers/eisa/Kconfig"
1832 bool "MCA support" if !X86_VOYAGER
1833 default y if X86_VOYAGER
1835 MicroChannel Architecture is found in some IBM PS/2 machines and
1836 laptops. It is a bus system similar to PCI or ISA. See
1837 <file:Documentation/mca.txt> (and especially the web page given
1838 there) before attempting to build an MCA bus kernel.
1840 source "drivers/mca/Kconfig"
1843 tristate "NatSemi SCx200 support"
1844 depends on !X86_VOYAGER
1846 This provides basic support for National Semiconductor's
1847 (now AMD's) Geode processors. The driver probes for the
1848 PCI-IDs of several on-chip devices, so its a good dependency
1849 for other scx200_* drivers.
1851 If compiled as a module, the driver is named scx200.
1853 config SCx200HR_TIMER
1854 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1855 depends on SCx200 && GENERIC_TIME
1858 This driver provides a clocksource built upon the on-chip
1859 27MHz high-resolution timer. Its also a workaround for
1860 NSC Geode SC-1100's buggy TSC, which loses time when the
1861 processor goes idle (as is done by the scheduler). The
1862 other workaround is idle=poll boot option.
1864 config GEODE_MFGPT_TIMER
1866 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1867 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1869 This driver provides a clock event source based on the MFGPT
1870 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1871 MFGPTs have a better resolution and max interval than the
1872 generic PIT, and are suitable for use as high-res timers.
1875 bool "One Laptop Per Child support"
1878 Add support for detecting the unique features of the OLPC
1885 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1887 source "drivers/pcmcia/Kconfig"
1889 source "drivers/pci/hotplug/Kconfig"
1894 menu "Executable file formats / Emulations"
1896 source "fs/Kconfig.binfmt"
1898 config IA32_EMULATION
1899 bool "IA32 Emulation"
1901 select COMPAT_BINFMT_ELF
1903 Include code to run 32-bit programs under a 64-bit kernel. You should
1904 likely turn this on, unless you're 100% sure that you don't have any
1905 32-bit programs left.
1908 tristate "IA32 a.out support"
1909 depends on IA32_EMULATION
1911 Support old a.out binaries in the 32bit emulation.
1915 depends on IA32_EMULATION
1917 config COMPAT_FOR_U64_ALIGNMENT
1921 config SYSVIPC_COMPAT
1923 depends on COMPAT && SYSVIPC
1928 config HAVE_ATOMIC_IOMAP
1932 source "net/Kconfig"
1934 source "drivers/Kconfig"
1936 source "drivers/firmware/Kconfig"
1940 source "arch/x86/Kconfig.debug"
1942 source "security/Kconfig"
1944 source "crypto/Kconfig"
1946 source "arch/x86/kvm/Kconfig"
1948 source "lib/Kconfig"
projects / linux-2.6 / blob