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
22 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IOREMAP_PROT
27 select ARCH_WANT_OPTIONAL_GPIOLIB
28 select HAVE_KRETPROBES
29 select HAVE_FTRACE_MCOUNT_RECORD
30 select HAVE_DYNAMIC_FTRACE
31 select HAVE_FUNCTION_TRACER
32 select HAVE_FUNCTION_GRAPH_TRACER
33 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
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
39 select USER_STACKTRACE_SUPPORT
43 default "arch/x86/configs/i386_defconfig" if X86_32
44 default "arch/x86/configs/x86_64_defconfig" if X86_64
49 config GENERIC_CMOS_UPDATE
52 config CLOCKSOURCE_WATCHDOG
55 config GENERIC_CLOCKEVENTS
58 config GENERIC_CLOCKEVENTS_BROADCAST
60 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
62 config LOCKDEP_SUPPORT
65 config STACKTRACE_SUPPORT
68 config HAVE_LATENCYTOP_SUPPORT
71 config FAST_CMPXCHG_LOCAL
84 config GENERIC_ISA_DMA
94 config GENERIC_HWEIGHT
100 config ARCH_MAY_HAVE_PC_FDC
103 config RWSEM_GENERIC_SPINLOCK
106 config RWSEM_XCHGADD_ALGORITHM
109 config ARCH_HAS_CPU_IDLE_WAIT
112 config GENERIC_CALIBRATE_DELAY
115 config GENERIC_TIME_VSYSCALL
119 config ARCH_HAS_CPU_RELAX
122 config ARCH_HAS_DEFAULT_IDLE
125 config ARCH_HAS_CACHE_LINE_SIZE
128 config HAVE_SETUP_PER_CPU_AREA
129 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
131 config HAVE_CPUMASK_OF_CPU_MAP
134 config ARCH_HIBERNATION_POSSIBLE
136 depends on !SMP || !X86_VOYAGER
138 config ARCH_SUSPEND_POSSIBLE
140 depends on !X86_VOYAGER
146 config ARCH_POPULATES_NODE_MAP
153 config ARCH_SUPPORTS_OPTIMIZED_INLINING
156 # Use the generic interrupt handling code in kernel/irq/:
157 config GENERIC_HARDIRQS
161 config GENERIC_IRQ_PROBE
165 config GENERIC_PENDING_IRQ
167 depends on GENERIC_HARDIRQS && SMP
172 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
175 config USE_GENERIC_SMP_HELPERS
181 depends on X86_32 && SMP
185 depends on X86_64 && SMP
190 depends on (X86_32 && !X86_VOYAGER) || X86_64
193 config X86_BIOS_REBOOT
195 depends on !X86_VOYAGER
198 config X86_TRAMPOLINE
200 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
205 source "init/Kconfig"
206 source "kernel/Kconfig.freezer"
208 menu "Processor type and features"
210 source "kernel/time/Kconfig"
213 bool "Symmetric multi-processing support"
215 This enables support for systems with more than one CPU. If you have
216 a system with only one CPU, like most personal computers, say N. If
217 you have a system with more than one CPU, say Y.
219 If you say N here, the kernel will run on single and multiprocessor
220 machines, but will use only one CPU of a multiprocessor machine. If
221 you say Y here, the kernel will run on many, but not all,
222 singleprocessor machines. On a singleprocessor machine, the kernel
223 will run faster if you say N here.
225 Note that if you say Y here and choose architecture "586" or
226 "Pentium" under "Processor family", the kernel will not work on 486
227 architectures. Similarly, multiprocessor kernels for the "PPro"
228 architecture may not work on all Pentium based boards.
230 People using multiprocessor machines who say Y here should also say
231 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
232 Management" code will be disabled if you say Y here.
234 See also <file:Documentation/i386/IO-APIC.txt>,
235 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
236 <http://www.tldp.org/docs.html#howto>.
238 If you don't know what to do here, say N.
240 config X86_HAS_BOOT_CPU_ID
242 depends on X86_VOYAGER
245 bool "Support sparse irq numbering"
246 depends on (PCI_MSI || HT_IRQ) && SMP
249 This enables support for sparse irq, esp for msi/msi-x. You may need
250 if you have lots of cards supports msi-x installed.
252 If you don't know what to do here, say Y.
254 config X86_FIND_SMP_CONFIG
256 depends on X86_MPPARSE || X86_VOYAGER
261 bool "Enable MPS table"
262 depends on X86_LOCAL_APIC
264 For old smp systems that do not have proper acpi support. Newer systems
265 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
271 depends on X86_LOCAL_APIC
275 prompt "Subarchitecture Type"
281 Choose this option if your computer is a standard PC or compatible.
287 Select this for an AMD Elan processor.
289 Do not use this option for K6/Athlon/Opteron processors!
291 If unsure, choose "PC-compatible" instead.
295 depends on X86_32 && (SMP || BROKEN) && !PCI
297 Voyager is an MCA-based 32-way capable SMP architecture proprietary
298 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
302 If you do not specifically know you have a Voyager based machine,
303 say N here, otherwise the kernel you build will not be bootable.
305 config X86_GENERICARCH
306 bool "Generic architecture"
309 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
310 subarchitectures. It is intended for a generic binary kernel.
311 if you select them all, kernel will probe it one by one. and will
317 bool "NUMAQ (IBM/Sequent)"
318 depends on SMP && X86_32 && PCI && X86_MPPARSE
321 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
322 NUMA multiquad box. This changes the way that processors are
323 bootstrapped, and uses Clustered Logical APIC addressing mode instead
324 of Flat Logical. You will need a new lynxer.elf file to flash your
325 firmware with - send email to <Martin.Bligh@us.ibm.com>.
328 bool "Summit/EXA (IBM x440)"
329 depends on X86_32 && SMP
331 This option is needed for IBM systems that use the Summit/EXA chipset.
332 In particular, it is needed for the x440.
335 bool "Support for Unisys ES7000 IA32 series"
336 depends on X86_32 && SMP
338 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
339 supposed to run on an IA32-based Unisys ES7000 system.
342 bool "Support for big SMP systems with more than 8 CPUs"
343 depends on X86_32 && SMP
345 This option is needed for the systems that have more than 8 CPUs
346 and if the system is not of any sub-arch type above.
351 bool "Support for ScaleMP vSMP"
353 depends on X86_64 && PCI
355 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
356 supposed to run on these EM64T-based machines. Only choose this option
357 if you have one of these machines.
362 bool "SGI 320/540 (Visual Workstation)"
363 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
365 The SGI Visual Workstation series is an IA32-based workstation
366 based on SGI systems chips with some legacy PC hardware attached.
368 Say Y here to create a kernel to run on the SGI 320 or 540.
370 A kernel compiled for the Visual Workstation will run on general
371 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
374 bool "RDC R-321x SoC"
377 select X86_REBOOTFIXUPS
379 This option is needed for RDC R-321x system-on-chip, also known
381 If you don't have one of these chips, you should say N here.
383 config SCHED_OMIT_FRAME_POINTER
385 prompt "Single-depth WCHAN output"
388 Calculate simpler /proc/<PID>/wchan values. If this option
389 is disabled then wchan values will recurse back to the
390 caller function. This provides more accurate wchan values,
391 at the expense of slightly more scheduling overhead.
393 If in doubt, say "Y".
395 menuconfig PARAVIRT_GUEST
396 bool "Paravirtualized guest support"
398 Say Y here to get to see options related to running Linux under
399 various hypervisors. This option alone does not add any kernel code.
401 If you say N, all options in this submenu will be skipped and disabled.
405 source "arch/x86/xen/Kconfig"
408 bool "VMI Guest support"
411 depends on !X86_VOYAGER
413 VMI provides a paravirtualized interface to the VMware ESX server
414 (it could be used by other hypervisors in theory too, but is not
415 at the moment), by linking the kernel to a GPL-ed ROM module
416 provided by the hypervisor.
419 bool "KVM paravirtualized clock"
421 select PARAVIRT_CLOCK
422 depends on !X86_VOYAGER
424 Turning on this option will allow you to run a paravirtualized clock
425 when running over the KVM hypervisor. Instead of relying on a PIT
426 (or probably other) emulation by the underlying device model, the host
427 provides the guest with timing infrastructure such as time of day, and
431 bool "KVM Guest support"
433 depends on !X86_VOYAGER
435 This option enables various optimizations for running under the KVM
438 source "arch/x86/lguest/Kconfig"
441 bool "Enable paravirtualization code"
442 depends on !X86_VOYAGER
444 This changes the kernel so it can modify itself when it is run
445 under a hypervisor, potentially improving performance significantly
446 over full virtualization. However, when run without a hypervisor
447 the kernel is theoretically slower and slightly larger.
449 config PARAVIRT_CLOCK
455 config PARAVIRT_DEBUG
456 bool "paravirt-ops debugging"
457 depends on PARAVIRT && DEBUG_KERNEL
459 Enable to debug paravirt_ops internals. Specifically, BUG if
460 a paravirt_op is missing when it is called.
465 This option adds a kernel parameter 'memtest', which allows memtest
467 memtest=0, mean disabled; -- default
468 memtest=1, mean do 1 test pattern;
470 memtest=4, mean do 4 test patterns.
471 If you are unsure how to answer this question, answer N.
473 config X86_SUMMIT_NUMA
475 depends on X86_32 && NUMA && X86_GENERICARCH
477 config X86_CYCLONE_TIMER
479 depends on X86_GENERICARCH
481 source "arch/x86/Kconfig.cpu"
485 prompt "HPET Timer Support" if X86_32
487 Use the IA-PC HPET (High Precision Event Timer) to manage
488 time in preference to the PIT and RTC, if a HPET is
490 HPET is the next generation timer replacing legacy 8254s.
491 The HPET provides a stable time base on SMP
492 systems, unlike the TSC, but it is more expensive to access,
493 as it is off-chip. You can find the HPET spec at
494 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
496 You can safely choose Y here. However, HPET will only be
497 activated if the platform and the BIOS support this feature.
498 Otherwise the 8254 will be used for timing services.
500 Choose N to continue using the legacy 8254 timer.
502 config HPET_EMULATE_RTC
504 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
506 # Mark as embedded because too many people got it wrong.
507 # The code disables itself when not needed.
510 bool "Enable DMI scanning" if EMBEDDED
512 Enabled scanning of DMI to identify machine quirks. Say Y
513 here unless you have verified that your setup is not
514 affected by entries in the DMI blacklist. Required by PNP
518 bool "GART IOMMU support" if EMBEDDED
522 depends on X86_64 && PCI
524 Support for full DMA access of devices with 32bit memory access only
525 on systems with more than 3GB. This is usually needed for USB,
526 sound, many IDE/SATA chipsets and some other devices.
527 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
528 based hardware IOMMU and a software bounce buffer based IOMMU used
529 on Intel systems and as fallback.
530 The code is only active when needed (enough memory and limited
531 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
535 bool "IBM Calgary IOMMU support"
537 depends on X86_64 && PCI && EXPERIMENTAL
539 Support for hardware IOMMUs in IBM's xSeries x366 and x460
540 systems. Needed to run systems with more than 3GB of memory
541 properly with 32-bit PCI devices that do not support DAC
542 (Double Address Cycle). Calgary also supports bus level
543 isolation, where all DMAs pass through the IOMMU. This
544 prevents them from going anywhere except their intended
545 destination. This catches hard-to-find kernel bugs and
546 mis-behaving drivers and devices that do not use the DMA-API
547 properly to set up their DMA buffers. The IOMMU can be
548 turned off at boot time with the iommu=off parameter.
549 Normally the kernel will make the right choice by itself.
552 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
554 prompt "Should Calgary be enabled by default?"
555 depends on CALGARY_IOMMU
557 Should Calgary be enabled by default? if you choose 'y', Calgary
558 will be used (if it exists). If you choose 'n', Calgary will not be
559 used even if it exists. If you choose 'n' and would like to use
560 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
564 bool "AMD IOMMU support"
567 depends on X86_64 && PCI && ACPI
569 With this option you can enable support for AMD IOMMU hardware in
570 your system. An IOMMU is a hardware component which provides
571 remapping of DMA memory accesses from devices. With an AMD IOMMU you
572 can isolate the the DMA memory of different devices and protect the
573 system from misbehaving device drivers or hardware.
575 You can find out if your system has an AMD IOMMU if you look into
576 your BIOS for an option to enable it or if you have an IVRS ACPI
579 # need this always selected by IOMMU for the VIA workaround
583 Support for software bounce buffers used on x86-64 systems
584 which don't have a hardware IOMMU (e.g. the current generation
585 of Intel's x86-64 CPUs). Using this PCI devices which can only
586 access 32-bits of memory can be used on systems with more than
587 3 GB of memory. If unsure, say Y.
590 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
593 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
594 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
595 select CPUMASK_OFFSTACK
598 Configure maximum number of CPUS and NUMA Nodes for this architecture.
602 int "Maximum number of CPUs" if SMP && !MAXSMP
603 range 2 512 if SMP && !MAXSMP
605 default "4096" if MAXSMP
606 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
609 This allows you to specify the maximum number of CPUs which this
610 kernel will support. The maximum supported value is 512 and the
611 minimum value which makes sense is 2.
613 This is purely to save memory - each supported CPU adds
614 approximately eight kilobytes to the kernel image.
617 bool "SMT (Hyperthreading) scheduler support"
620 SMT scheduler support improves the CPU scheduler's decision making
621 when dealing with Intel Pentium 4 chips with HyperThreading at a
622 cost of slightly increased overhead in some places. If unsure say
627 prompt "Multi-core scheduler support"
630 Multi-core scheduler support improves the CPU scheduler's decision
631 making when dealing with multi-core CPU chips at a cost of slightly
632 increased overhead in some places. If unsure say N here.
634 source "kernel/Kconfig.preempt"
637 bool "Local APIC support on uniprocessors"
638 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
640 A local APIC (Advanced Programmable Interrupt Controller) is an
641 integrated interrupt controller in the CPU. If you have a single-CPU
642 system which has a processor with a local APIC, you can say Y here to
643 enable and use it. If you say Y here even though your machine doesn't
644 have a local APIC, then the kernel will still run with no slowdown at
645 all. The local APIC supports CPU-generated self-interrupts (timer,
646 performance counters), and the NMI watchdog which detects hard
650 bool "IO-APIC support on uniprocessors"
651 depends on X86_UP_APIC
653 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
654 SMP-capable replacement for PC-style interrupt controllers. Most
655 SMP systems and many recent uniprocessor systems have one.
657 If you have a single-CPU system with an IO-APIC, you can say Y here
658 to use it. If you say Y here even though your machine doesn't have
659 an IO-APIC, then the kernel will still run with no slowdown at all.
661 config X86_LOCAL_APIC
663 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
667 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
669 config X86_VISWS_APIC
671 depends on X86_32 && X86_VISWS
674 bool "Machine Check Exception"
675 depends on !X86_VOYAGER
677 Machine Check Exception support allows the processor to notify the
678 kernel if it detects a problem (e.g. overheating, component failure).
679 The action the kernel takes depends on the severity of the problem,
680 ranging from a warning message on the console, to halting the machine.
681 Your processor must be a Pentium or newer to support this - check the
682 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
683 have a design flaw which leads to false MCE events - hence MCE is
684 disabled on all P5 processors, unless explicitly enabled with "mce"
685 as a boot argument. Similarly, if MCE is built in and creates a
686 problem on some new non-standard machine, you can boot with "nomce"
687 to disable it. MCE support simply ignores non-MCE processors like
688 the 386 and 486, so nearly everyone can say Y here.
692 prompt "Intel MCE features"
693 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
695 Additional support for intel specific MCE features such as
700 prompt "AMD MCE features"
701 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
703 Additional support for AMD specific MCE features such as
704 the DRAM Error Threshold.
706 config X86_MCE_NONFATAL
707 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
708 depends on X86_32 && X86_MCE
710 Enabling this feature starts a timer that triggers every 5 seconds which
711 will look at the machine check registers to see if anything happened.
712 Non-fatal problems automatically get corrected (but still logged).
713 Disable this if you don't want to see these messages.
714 Seeing the messages this option prints out may be indicative of dying
715 or out-of-spec (ie, overclocked) hardware.
716 This option only does something on certain CPUs.
717 (AMD Athlon/Duron and Intel Pentium 4)
719 config X86_MCE_P4THERMAL
720 bool "check for P4 thermal throttling interrupt."
721 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
723 Enabling this feature will cause a message to be printed when the P4
724 enters thermal throttling.
727 bool "Enable VM86 support" if EMBEDDED
731 This option is required by programs like DOSEMU to run 16-bit legacy
732 code on X86 processors. It also may be needed by software like
733 XFree86 to initialize some video cards via BIOS. Disabling this
734 option saves about 6k.
737 tristate "Toshiba Laptop support"
740 This adds a driver to safely access the System Management Mode of
741 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
742 not work on models with a Phoenix BIOS. The System Management Mode
743 is used to set the BIOS and power saving options on Toshiba portables.
745 For information on utilities to make use of this driver see the
746 Toshiba Linux utilities web site at:
747 <http://www.buzzard.org.uk/toshiba/>.
749 Say Y if you intend to run this kernel on a Toshiba portable.
753 tristate "Dell laptop support"
755 This adds a driver to safely access the System Management Mode
756 of the CPU on the Dell Inspiron 8000. The System Management Mode
757 is used to read cpu temperature and cooling fan status and to
758 control the fans on the I8K portables.
760 This driver has been tested only on the Inspiron 8000 but it may
761 also work with other Dell laptops. You can force loading on other
762 models by passing the parameter `force=1' to the module. Use at
765 For information on utilities to make use of this driver see the
766 I8K Linux utilities web site at:
767 <http://people.debian.org/~dz/i8k/>
769 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
772 config X86_REBOOTFIXUPS
773 bool "Enable X86 board specific fixups for reboot"
776 This enables chipset and/or board specific fixups to be done
777 in order to get reboot to work correctly. This is only needed on
778 some combinations of hardware and BIOS. The symptom, for which
779 this config is intended, is when reboot ends with a stalled/hung
782 Currently, the only fixup is for the Geode machines using
783 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
785 Say Y if you want to enable the fixup. Currently, it's safe to
786 enable this option even if you don't need it.
790 tristate "/dev/cpu/microcode - microcode support"
793 If you say Y here, you will be able to update the microcode on
794 certain Intel and AMD processors. The Intel support is for the
795 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
796 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
797 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
798 You will obviously need the actual microcode binary data itself
799 which is not shipped with the Linux kernel.
801 This option selects the general module only, you need to select
802 at least one vendor specific module as well.
804 To compile this driver as a module, choose M here: the
805 module will be called microcode.
807 config MICROCODE_INTEL
808 bool "Intel microcode patch loading support"
813 This options enables microcode patch loading support for Intel
816 For latest news and information on obtaining all the required
817 Intel ingredients for this driver, check:
818 <http://www.urbanmyth.org/microcode/>.
821 bool "AMD microcode patch loading support"
825 If you select this option, microcode patch loading support for AMD
826 processors will be enabled.
828 config MICROCODE_OLD_INTERFACE
833 tristate "/dev/cpu/*/msr - Model-specific register support"
835 This device gives privileged processes access to the x86
836 Model-Specific Registers (MSRs). It is a character device with
837 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
838 MSR accesses are directed to a specific CPU on multi-processor
842 tristate "/dev/cpu/*/cpuid - CPU information support"
844 This device gives processes access to the x86 CPUID instruction to
845 be executed on a specific processor. It is a character device
846 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
850 prompt "High Memory Support"
851 default HIGHMEM4G if !X86_NUMAQ
852 default HIGHMEM64G if X86_NUMAQ
857 depends on !X86_NUMAQ
859 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
860 However, the address space of 32-bit x86 processors is only 4
861 Gigabytes large. That means that, if you have a large amount of
862 physical memory, not all of it can be "permanently mapped" by the
863 kernel. The physical memory that's not permanently mapped is called
866 If you are compiling a kernel which will never run on a machine with
867 more than 1 Gigabyte total physical RAM, answer "off" here (default
868 choice and suitable for most users). This will result in a "3GB/1GB"
869 split: 3GB are mapped so that each process sees a 3GB virtual memory
870 space and the remaining part of the 4GB virtual memory space is used
871 by the kernel to permanently map as much physical memory as
874 If the machine has between 1 and 4 Gigabytes physical RAM, then
877 If more than 4 Gigabytes is used then answer "64GB" here. This
878 selection turns Intel PAE (Physical Address Extension) mode on.
879 PAE implements 3-level paging on IA32 processors. PAE is fully
880 supported by Linux, PAE mode is implemented on all recent Intel
881 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
882 then the kernel will not boot on CPUs that don't support PAE!
884 The actual amount of total physical memory will either be
885 auto detected or can be forced by using a kernel command line option
886 such as "mem=256M". (Try "man bootparam" or see the documentation of
887 your boot loader (lilo or loadlin) about how to pass options to the
888 kernel at boot time.)
890 If unsure, say "off".
894 depends on !X86_NUMAQ
896 Select this if you have a 32-bit processor and between 1 and 4
897 gigabytes of physical RAM.
901 depends on !M386 && !M486
904 Select this if you have a 32-bit processor and more than 4
905 gigabytes of physical RAM.
910 depends on EXPERIMENTAL
911 prompt "Memory split" if EMBEDDED
915 Select the desired split between kernel and user memory.
917 If the address range available to the kernel is less than the
918 physical memory installed, the remaining memory will be available
919 as "high memory". Accessing high memory is a little more costly
920 than low memory, as it needs to be mapped into the kernel first.
921 Note that increasing the kernel address space limits the range
922 available to user programs, making the address space there
923 tighter. Selecting anything other than the default 3G/1G split
924 will also likely make your kernel incompatible with binary-only
927 If you are not absolutely sure what you are doing, leave this
931 bool "3G/1G user/kernel split"
932 config VMSPLIT_3G_OPT
934 bool "3G/1G user/kernel split (for full 1G low memory)"
936 bool "2G/2G user/kernel split"
937 config VMSPLIT_2G_OPT
939 bool "2G/2G user/kernel split (for full 2G low memory)"
941 bool "1G/3G user/kernel split"
946 default 0xB0000000 if VMSPLIT_3G_OPT
947 default 0x80000000 if VMSPLIT_2G
948 default 0x78000000 if VMSPLIT_2G_OPT
949 default 0x40000000 if VMSPLIT_1G
955 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
958 bool "PAE (Physical Address Extension) Support"
959 depends on X86_32 && !HIGHMEM4G
961 PAE is required for NX support, and furthermore enables
962 larger swapspace support for non-overcommit purposes. It
963 has the cost of more pagetable lookup overhead, and also
964 consumes more pagetable space per process.
966 config ARCH_PHYS_ADDR_T_64BIT
967 def_bool X86_64 || X86_PAE
969 # Common NUMA Features
971 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
973 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
975 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
977 Enable NUMA (Non Uniform Memory Access) support.
978 The kernel will try to allocate memory used by a CPU on the
979 local memory controller of the CPU and add some more
980 NUMA awareness to the kernel.
982 For 32-bit this is currently highly experimental and should be only
983 used for kernel development. It might also cause boot failures.
984 For 64-bit this is recommended on all multiprocessor Opteron systems.
985 If the system is EM64T, you should say N unless your system is
988 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
989 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
993 prompt "Old style AMD Opteron NUMA detection"
994 depends on X86_64 && NUMA && PCI
996 Enable K8 NUMA node topology detection. You should say Y here if
997 you have a multi processor AMD K8 system. This uses an old
998 method to read the NUMA configuration directly from the builtin
999 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1000 instead, which also takes priority if both are compiled in.
1002 config X86_64_ACPI_NUMA
1004 prompt "ACPI NUMA detection"
1005 depends on X86_64 && NUMA && ACPI && PCI
1008 Enable ACPI SRAT based node topology detection.
1010 # Some NUMA nodes have memory ranges that span
1011 # other nodes. Even though a pfn is valid and
1012 # between a node's start and end pfns, it may not
1013 # reside on that node. See memmap_init_zone()
1015 config NODES_SPAN_OTHER_NODES
1017 depends on X86_64_ACPI_NUMA
1020 bool "NUMA emulation"
1021 depends on X86_64 && NUMA
1023 Enable NUMA emulation. A flat machine will be split
1024 into virtual nodes when booted with "numa=fake=N", where N is the
1025 number of nodes. This is only useful for debugging.
1028 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1030 default "9" if MAXSMP
1031 default "6" if X86_64
1032 default "4" if X86_NUMAQ
1034 depends on NEED_MULTIPLE_NODES
1036 Specify the maximum number of NUMA Nodes available on the target
1037 system. Increases memory reserved to accomodate various tables.
1039 config HAVE_ARCH_BOOTMEM_NODE
1041 depends on X86_32 && NUMA
1043 config ARCH_HAVE_MEMORY_PRESENT
1045 depends on X86_32 && DISCONTIGMEM
1047 config NEED_NODE_MEMMAP_SIZE
1049 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1051 config HAVE_ARCH_ALLOC_REMAP
1053 depends on X86_32 && NUMA
1055 config ARCH_FLATMEM_ENABLE
1057 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1059 config ARCH_DISCONTIGMEM_ENABLE
1061 depends on NUMA && X86_32
1063 config ARCH_DISCONTIGMEM_DEFAULT
1065 depends on NUMA && X86_32
1067 config ARCH_SPARSEMEM_DEFAULT
1071 config ARCH_SPARSEMEM_ENABLE
1073 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1074 select SPARSEMEM_STATIC if X86_32
1075 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1077 config ARCH_SELECT_MEMORY_MODEL
1079 depends on ARCH_SPARSEMEM_ENABLE
1081 config ARCH_MEMORY_PROBE
1083 depends on MEMORY_HOTPLUG
1088 bool "Allocate 3rd-level pagetables from highmem"
1089 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1091 The VM uses one page table entry for each page of physical memory.
1092 For systems with a lot of RAM, this can be wasteful of precious
1093 low memory. Setting this option will put user-space page table
1094 entries in high memory.
1096 config X86_CHECK_BIOS_CORRUPTION
1097 bool "Check for low memory corruption"
1099 Periodically check for memory corruption in low memory, which
1100 is suspected to be caused by BIOS. Even when enabled in the
1101 configuration, it is disabled at runtime. Enable it by
1102 setting "memory_corruption_check=1" on the kernel command
1103 line. By default it scans the low 64k of memory every 60
1104 seconds; see the memory_corruption_check_size and
1105 memory_corruption_check_period parameters in
1106 Documentation/kernel-parameters.txt to adjust this.
1108 When enabled with the default parameters, this option has
1109 almost no overhead, as it reserves a relatively small amount
1110 of memory and scans it infrequently. It both detects corruption
1111 and prevents it from affecting the running system.
1113 It is, however, intended as a diagnostic tool; if repeatable
1114 BIOS-originated corruption always affects the same memory,
1115 you can use memmap= to prevent the kernel from using that
1118 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1119 bool "Set the default setting of memory_corruption_check"
1120 depends on X86_CHECK_BIOS_CORRUPTION
1123 Set whether the default state of memory_corruption_check is
1126 config X86_RESERVE_LOW_64K
1127 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1130 Reserve the first 64K of physical RAM on BIOSes that are known
1131 to potentially corrupt that memory range. A numbers of BIOSes are
1132 known to utilize this area during suspend/resume, so it must not
1133 be used by the kernel.
1135 Set this to N if you are absolutely sure that you trust the BIOS
1136 to get all its memory reservations and usages right.
1138 If you have doubts about the BIOS (e.g. suspend/resume does not
1139 work or there's kernel crashes after certain hardware hotplug
1140 events) and it's not AMI or Phoenix, then you might want to enable
1141 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1142 corruption patterns.
1146 config MATH_EMULATION
1148 prompt "Math emulation" if X86_32
1150 Linux can emulate a math coprocessor (used for floating point
1151 operations) if you don't have one. 486DX and Pentium processors have
1152 a math coprocessor built in, 486SX and 386 do not, unless you added
1153 a 487DX or 387, respectively. (The messages during boot time can
1154 give you some hints here ["man dmesg"].) Everyone needs either a
1155 coprocessor or this emulation.
1157 If you don't have a math coprocessor, you need to say Y here; if you
1158 say Y here even though you have a coprocessor, the coprocessor will
1159 be used nevertheless. (This behavior can be changed with the kernel
1160 command line option "no387", which comes handy if your coprocessor
1161 is broken. Try "man bootparam" or see the documentation of your boot
1162 loader (lilo or loadlin) about how to pass options to the kernel at
1163 boot time.) This means that it is a good idea to say Y here if you
1164 intend to use this kernel on different machines.
1166 More information about the internals of the Linux math coprocessor
1167 emulation can be found in <file:arch/x86/math-emu/README>.
1169 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1170 kernel, it won't hurt.
1173 bool "MTRR (Memory Type Range Register) support"
1175 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1176 the Memory Type Range Registers (MTRRs) may be used to control
1177 processor access to memory ranges. This is most useful if you have
1178 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1179 allows bus write transfers to be combined into a larger transfer
1180 before bursting over the PCI/AGP bus. This can increase performance
1181 of image write operations 2.5 times or more. Saying Y here creates a
1182 /proc/mtrr file which may be used to manipulate your processor's
1183 MTRRs. Typically the X server should use this.
1185 This code has a reasonably generic interface so that similar
1186 control registers on other processors can be easily supported
1189 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1190 Registers (ARRs) which provide a similar functionality to MTRRs. For
1191 these, the ARRs are used to emulate the MTRRs.
1192 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1193 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1194 write-combining. All of these processors are supported by this code
1195 and it makes sense to say Y here if you have one of them.
1197 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1198 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1199 can lead to all sorts of problems, so it's good to say Y here.
1201 You can safely say Y even if your machine doesn't have MTRRs, you'll
1202 just add about 9 KB to your kernel.
1204 See <file:Documentation/x86/mtrr.txt> for more information.
1206 config MTRR_SANITIZER
1208 prompt "MTRR cleanup support"
1211 Convert MTRR layout from continuous to discrete, so X drivers can
1212 add writeback entries.
1214 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1215 The largest mtrr entry size for a continous block can be set with
1220 config MTRR_SANITIZER_ENABLE_DEFAULT
1221 int "MTRR cleanup enable value (0-1)"
1224 depends on MTRR_SANITIZER
1226 Enable mtrr cleanup default value
1228 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1229 int "MTRR cleanup spare reg num (0-7)"
1232 depends on MTRR_SANITIZER
1234 mtrr cleanup spare entries default, it can be changed via
1235 mtrr_spare_reg_nr=N on the kernel command line.
1239 prompt "x86 PAT support"
1242 Use PAT attributes to setup page level cache control.
1244 PATs are the modern equivalents of MTRRs and are much more
1245 flexible than MTRRs.
1247 Say N here if you see bootup problems (boot crash, boot hang,
1248 spontaneous reboots) or a non-working video driver.
1253 bool "EFI runtime service support"
1256 This enables the kernel to use EFI runtime services that are
1257 available (such as the EFI variable services).
1259 This option is only useful on systems that have EFI firmware.
1260 In addition, you should use the latest ELILO loader available
1261 at <http://elilo.sourceforge.net> in order to take advantage
1262 of EFI runtime services. However, even with this option, the
1263 resultant kernel should continue to boot on existing non-EFI
1268 prompt "Enable seccomp to safely compute untrusted bytecode"
1270 This kernel feature is useful for number crunching applications
1271 that may need to compute untrusted bytecode during their
1272 execution. By using pipes or other transports made available to
1273 the process as file descriptors supporting the read/write
1274 syscalls, it's possible to isolate those applications in
1275 their own address space using seccomp. Once seccomp is
1276 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1277 and the task is only allowed to execute a few safe syscalls
1278 defined by each seccomp mode.
1280 If unsure, say Y. Only embedded should say N here.
1282 config CC_STACKPROTECTOR
1283 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1284 depends on X86_64 && EXPERIMENTAL && BROKEN
1286 This option turns on the -fstack-protector GCC feature. This
1287 feature puts, at the beginning of critical functions, a canary
1288 value on the stack just before the return address, and validates
1289 the value just before actually returning. Stack based buffer
1290 overflows (that need to overwrite this return address) now also
1291 overwrite the canary, which gets detected and the attack is then
1292 neutralized via a kernel panic.
1294 This feature requires gcc version 4.2 or above, or a distribution
1295 gcc with the feature backported. Older versions are automatically
1296 detected and for those versions, this configuration option is ignored.
1298 config CC_STACKPROTECTOR_ALL
1299 bool "Use stack-protector for all functions"
1300 depends on CC_STACKPROTECTOR
1302 Normally, GCC only inserts the canary value protection for
1303 functions that use large-ish on-stack buffers. By enabling
1304 this option, GCC will be asked to do this for ALL functions.
1306 source kernel/Kconfig.hz
1309 bool "kexec system call"
1310 depends on X86_BIOS_REBOOT
1312 kexec is a system call that implements the ability to shutdown your
1313 current kernel, and to start another kernel. It is like a reboot
1314 but it is independent of the system firmware. And like a reboot
1315 you can start any kernel with it, not just Linux.
1317 The name comes from the similarity to the exec system call.
1319 It is an ongoing process to be certain the hardware in a machine
1320 is properly shutdown, so do not be surprised if this code does not
1321 initially work for you. It may help to enable device hotplugging
1322 support. As of this writing the exact hardware interface is
1323 strongly in flux, so no good recommendation can be made.
1326 bool "kernel crash dumps"
1327 depends on X86_64 || (X86_32 && HIGHMEM)
1329 Generate crash dump after being started by kexec.
1330 This should be normally only set in special crash dump kernels
1331 which are loaded in the main kernel with kexec-tools into
1332 a specially reserved region and then later executed after
1333 a crash by kdump/kexec. The crash dump kernel must be compiled
1334 to a memory address not used by the main kernel or BIOS using
1335 PHYSICAL_START, or it must be built as a relocatable image
1336 (CONFIG_RELOCATABLE=y).
1337 For more details see Documentation/kdump/kdump.txt
1340 bool "kexec jump (EXPERIMENTAL)"
1341 depends on EXPERIMENTAL
1342 depends on KEXEC && HIBERNATION && X86_32
1344 Jump between original kernel and kexeced kernel and invoke
1345 code in physical address mode via KEXEC
1347 config PHYSICAL_START
1348 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1349 default "0x1000000" if X86_NUMAQ
1350 default "0x200000" if X86_64
1353 This gives the physical address where the kernel is loaded.
1355 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1356 bzImage will decompress itself to above physical address and
1357 run from there. Otherwise, bzImage will run from the address where
1358 it has been loaded by the boot loader and will ignore above physical
1361 In normal kdump cases one does not have to set/change this option
1362 as now bzImage can be compiled as a completely relocatable image
1363 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1364 address. This option is mainly useful for the folks who don't want
1365 to use a bzImage for capturing the crash dump and want to use a
1366 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1367 to be specifically compiled to run from a specific memory area
1368 (normally a reserved region) and this option comes handy.
1370 So if you are using bzImage for capturing the crash dump, leave
1371 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1372 Otherwise if you plan to use vmlinux for capturing the crash dump
1373 change this value to start of the reserved region (Typically 16MB
1374 0x1000000). In other words, it can be set based on the "X" value as
1375 specified in the "crashkernel=YM@XM" command line boot parameter
1376 passed to the panic-ed kernel. Typically this parameter is set as
1377 crashkernel=64M@16M. Please take a look at
1378 Documentation/kdump/kdump.txt for more details about crash dumps.
1380 Usage of bzImage for capturing the crash dump is recommended as
1381 one does not have to build two kernels. Same kernel can be used
1382 as production kernel and capture kernel. Above option should have
1383 gone away after relocatable bzImage support is introduced. But it
1384 is present because there are users out there who continue to use
1385 vmlinux for dump capture. This option should go away down the
1388 Don't change this unless you know what you are doing.
1391 bool "Build a relocatable kernel (EXPERIMENTAL)"
1392 depends on EXPERIMENTAL
1394 This builds a kernel image that retains relocation information
1395 so it can be loaded someplace besides the default 1MB.
1396 The relocations tend to make the kernel binary about 10% larger,
1397 but are discarded at runtime.
1399 One use is for the kexec on panic case where the recovery kernel
1400 must live at a different physical address than the primary
1403 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1404 it has been loaded at and the compile time physical address
1405 (CONFIG_PHYSICAL_START) is ignored.
1407 config PHYSICAL_ALIGN
1409 prompt "Alignment value to which kernel should be aligned" if X86_32
1410 default "0x100000" if X86_32
1411 default "0x200000" if X86_64
1412 range 0x2000 0x400000
1414 This value puts the alignment restrictions on physical address
1415 where kernel is loaded and run from. Kernel is compiled for an
1416 address which meets above alignment restriction.
1418 If bootloader loads the kernel at a non-aligned address and
1419 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1420 address aligned to above value and run from there.
1422 If bootloader loads the kernel at a non-aligned address and
1423 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1424 load address and decompress itself to the address it has been
1425 compiled for and run from there. The address for which kernel is
1426 compiled already meets above alignment restrictions. Hence the
1427 end result is that kernel runs from a physical address meeting
1428 above alignment restrictions.
1430 Don't change this unless you know what you are doing.
1433 bool "Support for hot-pluggable CPUs"
1434 depends on SMP && HOTPLUG && !X86_VOYAGER
1436 Say Y here to allow turning CPUs off and on. CPUs can be
1437 controlled through /sys/devices/system/cpu.
1438 ( Note: power management support will enable this option
1439 automatically on SMP systems. )
1440 Say N if you want to disable CPU hotplug.
1444 prompt "Compat VDSO support"
1445 depends on X86_32 || IA32_EMULATION
1447 Map the 32-bit VDSO to the predictable old-style address too.
1449 Say N here if you are running a sufficiently recent glibc
1450 version (2.3.3 or later), to remove the high-mapped
1451 VDSO mapping and to exclusively use the randomized VDSO.
1456 bool "Built-in kernel command line"
1459 Allow for specifying boot arguments to the kernel at
1460 build time. On some systems (e.g. embedded ones), it is
1461 necessary or convenient to provide some or all of the
1462 kernel boot arguments with the kernel itself (that is,
1463 to not rely on the boot loader to provide them.)
1465 To compile command line arguments into the kernel,
1466 set this option to 'Y', then fill in the
1467 the boot arguments in CONFIG_CMDLINE.
1469 Systems with fully functional boot loaders (i.e. non-embedded)
1470 should leave this option set to 'N'.
1473 string "Built-in kernel command string"
1474 depends on CMDLINE_BOOL
1477 Enter arguments here that should be compiled into the kernel
1478 image and used at boot time. If the boot loader provides a
1479 command line at boot time, it is appended to this string to
1480 form the full kernel command line, when the system boots.
1482 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1483 change this behavior.
1485 In most cases, the command line (whether built-in or provided
1486 by the boot loader) should specify the device for the root
1489 config CMDLINE_OVERRIDE
1490 bool "Built-in command line overrides boot loader arguments"
1492 depends on CMDLINE_BOOL
1494 Set this option to 'Y' to have the kernel ignore the boot loader
1495 command line, and use ONLY the built-in command line.
1497 This is used to work around broken boot loaders. This should
1498 be set to 'N' under normal conditions.
1502 config ARCH_ENABLE_MEMORY_HOTPLUG
1504 depends on X86_64 || (X86_32 && HIGHMEM)
1506 config HAVE_ARCH_EARLY_PFN_TO_NID
1510 menu "Power management and ACPI options"
1511 depends on !X86_VOYAGER
1513 config ARCH_HIBERNATION_HEADER
1515 depends on X86_64 && HIBERNATION
1517 source "kernel/power/Kconfig"
1519 source "drivers/acpi/Kconfig"
1524 depends on APM || APM_MODULE
1527 tristate "APM (Advanced Power Management) BIOS support"
1528 depends on X86_32 && PM_SLEEP
1530 APM is a BIOS specification for saving power using several different
1531 techniques. This is mostly useful for battery powered laptops with
1532 APM compliant BIOSes. If you say Y here, the system time will be
1533 reset after a RESUME operation, the /proc/apm device will provide
1534 battery status information, and user-space programs will receive
1535 notification of APM "events" (e.g. battery status change).
1537 If you select "Y" here, you can disable actual use of the APM
1538 BIOS by passing the "apm=off" option to the kernel at boot time.
1540 Note that the APM support is almost completely disabled for
1541 machines with more than one CPU.
1543 In order to use APM, you will need supporting software. For location
1544 and more information, read <file:Documentation/power/pm.txt> and the
1545 Battery Powered Linux mini-HOWTO, available from
1546 <http://www.tldp.org/docs.html#howto>.
1548 This driver does not spin down disk drives (see the hdparm(8)
1549 manpage ("man 8 hdparm") for that), and it doesn't turn off
1550 VESA-compliant "green" monitors.
1552 This driver does not support the TI 4000M TravelMate and the ACER
1553 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1554 desktop machines also don't have compliant BIOSes, and this driver
1555 may cause those machines to panic during the boot phase.
1557 Generally, if you don't have a battery in your machine, there isn't
1558 much point in using this driver and you should say N. If you get
1559 random kernel OOPSes or reboots that don't seem to be related to
1560 anything, try disabling/enabling this option (or disabling/enabling
1563 Some other things you should try when experiencing seemingly random,
1566 1) make sure that you have enough swap space and that it is
1568 2) pass the "no-hlt" option to the kernel
1569 3) switch on floating point emulation in the kernel and pass
1570 the "no387" option to the kernel
1571 4) pass the "floppy=nodma" option to the kernel
1572 5) pass the "mem=4M" option to the kernel (thereby disabling
1573 all but the first 4 MB of RAM)
1574 6) make sure that the CPU is not over clocked.
1575 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1576 8) disable the cache from your BIOS settings
1577 9) install a fan for the video card or exchange video RAM
1578 10) install a better fan for the CPU
1579 11) exchange RAM chips
1580 12) exchange the motherboard.
1582 To compile this driver as a module, choose M here: the
1583 module will be called apm.
1587 config APM_IGNORE_USER_SUSPEND
1588 bool "Ignore USER SUSPEND"
1590 This option will ignore USER SUSPEND requests. On machines with a
1591 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1592 series notebooks, it is necessary to say Y because of a BIOS bug.
1594 config APM_DO_ENABLE
1595 bool "Enable PM at boot time"
1597 Enable APM features at boot time. From page 36 of the APM BIOS
1598 specification: "When disabled, the APM BIOS does not automatically
1599 power manage devices, enter the Standby State, enter the Suspend
1600 State, or take power saving steps in response to CPU Idle calls."
1601 This driver will make CPU Idle calls when Linux is idle (unless this
1602 feature is turned off -- see "Do CPU IDLE calls", below). This
1603 should always save battery power, but more complicated APM features
1604 will be dependent on your BIOS implementation. You may need to turn
1605 this option off if your computer hangs at boot time when using APM
1606 support, or if it beeps continuously instead of suspending. Turn
1607 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1608 T400CDT. This is off by default since most machines do fine without
1612 bool "Make CPU Idle calls when idle"
1614 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1615 On some machines, this can activate improved power savings, such as
1616 a slowed CPU clock rate, when the machine is idle. These idle calls
1617 are made after the idle loop has run for some length of time (e.g.,
1618 333 mS). On some machines, this will cause a hang at boot time or
1619 whenever the CPU becomes idle. (On machines with more than one CPU,
1620 this option does nothing.)
1622 config APM_DISPLAY_BLANK
1623 bool "Enable console blanking using APM"
1625 Enable console blanking using the APM. Some laptops can use this to
1626 turn off the LCD backlight when the screen blanker of the Linux
1627 virtual console blanks the screen. Note that this is only used by
1628 the virtual console screen blanker, and won't turn off the backlight
1629 when using the X Window system. This also doesn't have anything to
1630 do with your VESA-compliant power-saving monitor. Further, this
1631 option doesn't work for all laptops -- it might not turn off your
1632 backlight at all, or it might print a lot of errors to the console,
1633 especially if you are using gpm.
1635 config APM_ALLOW_INTS
1636 bool "Allow interrupts during APM BIOS calls"
1638 Normally we disable external interrupts while we are making calls to
1639 the APM BIOS as a measure to lessen the effects of a badly behaving
1640 BIOS implementation. The BIOS should reenable interrupts if it
1641 needs to. Unfortunately, some BIOSes do not -- especially those in
1642 many of the newer IBM Thinkpads. If you experience hangs when you
1643 suspend, try setting this to Y. Otherwise, say N.
1647 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1649 source "drivers/cpuidle/Kconfig"
1651 source "drivers/idle/Kconfig"
1656 menu "Bus options (PCI etc.)"
1661 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1663 Find out whether you have a PCI motherboard. PCI is the name of a
1664 bus system, i.e. the way the CPU talks to the other stuff inside
1665 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1666 VESA. If you have PCI, say Y, otherwise N.
1669 prompt "PCI access mode"
1670 depends on X86_32 && PCI
1673 On PCI systems, the BIOS can be used to detect the PCI devices and
1674 determine their configuration. However, some old PCI motherboards
1675 have BIOS bugs and may crash if this is done. Also, some embedded
1676 PCI-based systems don't have any BIOS at all. Linux can also try to
1677 detect the PCI hardware directly without using the BIOS.
1679 With this option, you can specify how Linux should detect the
1680 PCI devices. If you choose "BIOS", the BIOS will be used,
1681 if you choose "Direct", the BIOS won't be used, and if you
1682 choose "MMConfig", then PCI Express MMCONFIG will be used.
1683 If you choose "Any", the kernel will try MMCONFIG, then the
1684 direct access method and falls back to the BIOS if that doesn't
1685 work. If unsure, go with the default, which is "Any".
1690 config PCI_GOMMCONFIG
1707 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1709 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1712 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1716 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1720 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1727 bool "Support mmconfig PCI config space access"
1728 depends on X86_64 && PCI && ACPI
1731 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1732 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1734 DMA remapping (DMAR) devices support enables independent address
1735 translations for Direct Memory Access (DMA) from devices.
1736 These DMA remapping devices are reported via ACPI tables
1737 and include PCI device scope covered by these DMA
1742 prompt "Support for Graphics workaround"
1745 Current Graphics drivers tend to use physical address
1746 for DMA and avoid using DMA APIs. Setting this config
1747 option permits the IOMMU driver to set a unity map for
1748 all the OS-visible memory. Hence the driver can continue
1749 to use physical addresses for DMA.
1751 config DMAR_FLOPPY_WA
1755 Floppy disk drivers are know to bypass DMA API calls
1756 thereby failing to work when IOMMU is enabled. This
1757 workaround will setup a 1:1 mapping for the first
1758 16M to make floppy (an ISA device) work.
1761 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1762 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1764 Supports Interrupt remapping for IO-APIC and MSI devices.
1765 To use x2apic mode in the CPU's which support x2APIC enhancements or
1766 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1768 source "drivers/pci/pcie/Kconfig"
1770 source "drivers/pci/Kconfig"
1772 # x86_64 have no ISA slots, but do have ISA-style DMA.
1780 depends on !X86_VOYAGER
1782 Find out whether you have ISA slots on your motherboard. ISA is the
1783 name of a bus system, i.e. the way the CPU talks to the other stuff
1784 inside your box. Other bus systems are PCI, EISA, MicroChannel
1785 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1786 newer boards don't support it. If you have ISA, say Y, otherwise N.
1792 The Extended Industry Standard Architecture (EISA) bus was
1793 developed as an open alternative to the IBM MicroChannel bus.
1795 The EISA bus provided some of the features of the IBM MicroChannel
1796 bus while maintaining backward compatibility with cards made for
1797 the older ISA bus. The EISA bus saw limited use between 1988 and
1798 1995 when it was made obsolete by the PCI bus.
1800 Say Y here if you are building a kernel for an EISA-based machine.
1804 source "drivers/eisa/Kconfig"
1807 bool "MCA support" if !X86_VOYAGER
1808 default y if X86_VOYAGER
1810 MicroChannel Architecture is found in some IBM PS/2 machines and
1811 laptops. It is a bus system similar to PCI or ISA. See
1812 <file:Documentation/mca.txt> (and especially the web page given
1813 there) before attempting to build an MCA bus kernel.
1815 source "drivers/mca/Kconfig"
1818 tristate "NatSemi SCx200 support"
1819 depends on !X86_VOYAGER
1821 This provides basic support for National Semiconductor's
1822 (now AMD's) Geode processors. The driver probes for the
1823 PCI-IDs of several on-chip devices, so its a good dependency
1824 for other scx200_* drivers.
1826 If compiled as a module, the driver is named scx200.
1828 config SCx200HR_TIMER
1829 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1830 depends on SCx200 && GENERIC_TIME
1833 This driver provides a clocksource built upon the on-chip
1834 27MHz high-resolution timer. Its also a workaround for
1835 NSC Geode SC-1100's buggy TSC, which loses time when the
1836 processor goes idle (as is done by the scheduler). The
1837 other workaround is idle=poll boot option.
1839 config GEODE_MFGPT_TIMER
1841 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1842 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1844 This driver provides a clock event source based on the MFGPT
1845 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1846 MFGPTs have a better resolution and max interval than the
1847 generic PIT, and are suitable for use as high-res timers.
1850 bool "One Laptop Per Child support"
1853 Add support for detecting the unique features of the OLPC
1860 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1862 source "drivers/pcmcia/Kconfig"
1864 source "drivers/pci/hotplug/Kconfig"
1869 menu "Executable file formats / Emulations"
1871 source "fs/Kconfig.binfmt"
1873 config IA32_EMULATION
1874 bool "IA32 Emulation"
1876 select COMPAT_BINFMT_ELF
1878 Include code to run 32-bit programs under a 64-bit kernel. You should
1879 likely turn this on, unless you're 100% sure that you don't have any
1880 32-bit programs left.
1883 tristate "IA32 a.out support"
1884 depends on IA32_EMULATION
1886 Support old a.out binaries in the 32bit emulation.
1890 depends on IA32_EMULATION
1892 config COMPAT_FOR_U64_ALIGNMENT
1896 config SYSVIPC_COMPAT
1898 depends on COMPAT && SYSVIPC
1903 config HAVE_ATOMIC_IOMAP
1907 source "net/Kconfig"
1909 source "drivers/Kconfig"
1911 source "drivers/firmware/Kconfig"
1915 source "arch/x86/Kconfig.debug"
1917 source "security/Kconfig"
1919 source "crypto/Kconfig"
1921 source "arch/x86/kvm/Kconfig"
1923 source "lib/Kconfig"
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