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 if X86_32
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
244 config X86_FIND_SMP_CONFIG
246 depends on X86_MPPARSE || X86_VOYAGER
251 bool "Enable MPS table"
252 depends on X86_LOCAL_APIC
254 For old smp systems that do not have proper acpi support. Newer systems
255 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
261 depends on X86_LOCAL_APIC
265 prompt "Subarchitecture Type"
271 Choose this option if your computer is a standard PC or compatible.
277 Select this for an AMD Elan processor.
279 Do not use this option for K6/Athlon/Opteron processors!
281 If unsure, choose "PC-compatible" instead.
285 depends on X86_32 && (SMP || BROKEN) && !PCI
287 Voyager is an MCA-based 32-way capable SMP architecture proprietary
288 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
292 If you do not specifically know you have a Voyager based machine,
293 say N here, otherwise the kernel you build will not be bootable.
295 config X86_GENERICARCH
296 bool "Generic architecture"
299 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
300 subarchitectures. It is intended for a generic binary kernel.
301 if you select them all, kernel will probe it one by one. and will
307 bool "NUMAQ (IBM/Sequent)"
308 depends on SMP && X86_32 && PCI && X86_MPPARSE
311 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
312 NUMA multiquad box. This changes the way that processors are
313 bootstrapped, and uses Clustered Logical APIC addressing mode instead
314 of Flat Logical. You will need a new lynxer.elf file to flash your
315 firmware with - send email to <Martin.Bligh@us.ibm.com>.
318 bool "Summit/EXA (IBM x440)"
319 depends on X86_32 && SMP
321 This option is needed for IBM systems that use the Summit/EXA chipset.
322 In particular, it is needed for the x440.
325 bool "Support for Unisys ES7000 IA32 series"
326 depends on X86_32 && SMP
328 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
329 supposed to run on an IA32-based Unisys ES7000 system.
332 bool "Support for big SMP systems with more than 8 CPUs"
333 depends on X86_32 && SMP
335 This option is needed for the systems that have more than 8 CPUs
336 and if the system is not of any sub-arch type above.
341 bool "Support for ScaleMP vSMP"
343 depends on X86_64 && PCI
345 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
346 supposed to run on these EM64T-based machines. Only choose this option
347 if you have one of these machines.
352 bool "SGI 320/540 (Visual Workstation)"
353 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
355 The SGI Visual Workstation series is an IA32-based workstation
356 based on SGI systems chips with some legacy PC hardware attached.
358 Say Y here to create a kernel to run on the SGI 320 or 540.
360 A kernel compiled for the Visual Workstation will run on general
361 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
364 bool "RDC R-321x SoC"
367 select X86_REBOOTFIXUPS
369 This option is needed for RDC R-321x system-on-chip, also known
371 If you don't have one of these chips, you should say N here.
373 config SCHED_NO_NO_OMIT_FRAME_POINTER
375 prompt "Single-depth WCHAN output"
378 Calculate simpler /proc/<PID>/wchan values. If this option
379 is disabled then wchan values will recurse back to the
380 caller function. This provides more accurate wchan values,
381 at the expense of slightly more scheduling overhead.
383 If in doubt, say "Y".
385 menuconfig PARAVIRT_GUEST
386 bool "Paravirtualized guest support"
388 Say Y here to get to see options related to running Linux under
389 various hypervisors. This option alone does not add any kernel code.
391 If you say N, all options in this submenu will be skipped and disabled.
395 source "arch/x86/xen/Kconfig"
398 bool "VMI Guest support"
401 depends on !X86_VOYAGER
403 VMI provides a paravirtualized interface to the VMware ESX server
404 (it could be used by other hypervisors in theory too, but is not
405 at the moment), by linking the kernel to a GPL-ed ROM module
406 provided by the hypervisor.
409 bool "KVM paravirtualized clock"
411 select PARAVIRT_CLOCK
412 depends on !X86_VOYAGER
414 Turning on this option will allow you to run a paravirtualized clock
415 when running over the KVM hypervisor. Instead of relying on a PIT
416 (or probably other) emulation by the underlying device model, the host
417 provides the guest with timing infrastructure such as time of day, and
421 bool "KVM Guest support"
423 depends on !X86_VOYAGER
425 This option enables various optimizations for running under the KVM
428 source "arch/x86/lguest/Kconfig"
431 bool "Enable paravirtualization code"
432 depends on !X86_VOYAGER
434 This changes the kernel so it can modify itself when it is run
435 under a hypervisor, potentially improving performance significantly
436 over full virtualization. However, when run without a hypervisor
437 the kernel is theoretically slower and slightly larger.
439 config PARAVIRT_CLOCK
445 config PARAVIRT_DEBUG
446 bool "paravirt-ops debugging"
447 depends on PARAVIRT && DEBUG_KERNEL
449 Enable to debug paravirt_ops internals. Specifically, BUG if
450 a paravirt_op is missing when it is called.
455 This option adds a kernel parameter 'memtest', which allows memtest
457 memtest=0, mean disabled; -- default
458 memtest=1, mean do 1 test pattern;
460 memtest=4, mean do 4 test patterns.
461 If you are unsure how to answer this question, answer N.
463 config X86_SUMMIT_NUMA
465 depends on X86_32 && NUMA && X86_GENERICARCH
467 config X86_CYCLONE_TIMER
469 depends on X86_GENERICARCH
471 config ES7000_CLUSTERED_APIC
473 depends on SMP && X86_ES7000 && MPENTIUMIII
475 source "arch/x86/Kconfig.cpu"
479 prompt "HPET Timer Support" if X86_32
481 Use the IA-PC HPET (High Precision Event Timer) to manage
482 time in preference to the PIT and RTC, if a HPET is
484 HPET is the next generation timer replacing legacy 8254s.
485 The HPET provides a stable time base on SMP
486 systems, unlike the TSC, but it is more expensive to access,
487 as it is off-chip. You can find the HPET spec at
488 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
490 You can safely choose Y here. However, HPET will only be
491 activated if the platform and the BIOS support this feature.
492 Otherwise the 8254 will be used for timing services.
494 Choose N to continue using the legacy 8254 timer.
496 config HPET_EMULATE_RTC
498 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
500 # Mark as embedded because too many people got it wrong.
501 # The code disables itself when not needed.
504 bool "Enable DMI scanning" if EMBEDDED
506 Enabled scanning of DMI to identify machine quirks. Say Y
507 here unless you have verified that your setup is not
508 affected by entries in the DMI blacklist. Required by PNP
512 bool "GART IOMMU support" if EMBEDDED
516 depends on X86_64 && PCI
518 Support for full DMA access of devices with 32bit memory access only
519 on systems with more than 3GB. This is usually needed for USB,
520 sound, many IDE/SATA chipsets and some other devices.
521 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
522 based hardware IOMMU and a software bounce buffer based IOMMU used
523 on Intel systems and as fallback.
524 The code is only active when needed (enough memory and limited
525 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
529 bool "IBM Calgary IOMMU support"
531 depends on X86_64 && PCI && EXPERIMENTAL
533 Support for hardware IOMMUs in IBM's xSeries x366 and x460
534 systems. Needed to run systems with more than 3GB of memory
535 properly with 32-bit PCI devices that do not support DAC
536 (Double Address Cycle). Calgary also supports bus level
537 isolation, where all DMAs pass through the IOMMU. This
538 prevents them from going anywhere except their intended
539 destination. This catches hard-to-find kernel bugs and
540 mis-behaving drivers and devices that do not use the DMA-API
541 properly to set up their DMA buffers. The IOMMU can be
542 turned off at boot time with the iommu=off parameter.
543 Normally the kernel will make the right choice by itself.
546 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
548 prompt "Should Calgary be enabled by default?"
549 depends on CALGARY_IOMMU
551 Should Calgary be enabled by default? if you choose 'y', Calgary
552 will be used (if it exists). If you choose 'n', Calgary will not be
553 used even if it exists. If you choose 'n' and would like to use
554 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
558 bool "AMD IOMMU support"
561 depends on X86_64 && PCI && ACPI
563 With this option you can enable support for AMD IOMMU hardware in
564 your system. An IOMMU is a hardware component which provides
565 remapping of DMA memory accesses from devices. With an AMD IOMMU you
566 can isolate the the DMA memory of different devices and protect the
567 system from misbehaving device drivers or hardware.
569 You can find out if your system has an AMD IOMMU if you look into
570 your BIOS for an option to enable it or if you have an IVRS ACPI
573 # need this always selected by IOMMU for the VIA workaround
577 Support for software bounce buffers used on x86-64 systems
578 which don't have a hardware IOMMU (e.g. the current generation
579 of Intel's x86-64 CPUs). Using this PCI devices which can only
580 access 32-bits of memory can be used on systems with more than
581 3 GB of memory. If unsure, say Y.
584 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
587 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
588 depends on X86_64 && SMP && BROKEN
591 Configure maximum number of CPUS and NUMA Nodes for this architecture.
595 int "Maximum number of CPUs (2-512)" if !MAXSMP
598 default "4096" if MAXSMP
599 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
602 This allows you to specify the maximum number of CPUs which this
603 kernel will support. The maximum supported value is 512 and the
604 minimum value which makes sense is 2.
606 This is purely to save memory - each supported CPU adds
607 approximately eight kilobytes to the kernel image.
610 bool "SMT (Hyperthreading) scheduler support"
613 SMT scheduler support improves the CPU scheduler's decision making
614 when dealing with Intel Pentium 4 chips with HyperThreading at a
615 cost of slightly increased overhead in some places. If unsure say
620 prompt "Multi-core scheduler support"
623 Multi-core scheduler support improves the CPU scheduler's decision
624 making when dealing with multi-core CPU chips at a cost of slightly
625 increased overhead in some places. If unsure say N here.
627 source "kernel/Kconfig.preempt"
630 bool "Local APIC support on uniprocessors"
631 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
633 A local APIC (Advanced Programmable Interrupt Controller) is an
634 integrated interrupt controller in the CPU. If you have a single-CPU
635 system which has a processor with a local APIC, you can say Y here to
636 enable and use it. If you say Y here even though your machine doesn't
637 have a local APIC, then the kernel will still run with no slowdown at
638 all. The local APIC supports CPU-generated self-interrupts (timer,
639 performance counters), and the NMI watchdog which detects hard
643 bool "IO-APIC support on uniprocessors"
644 depends on X86_UP_APIC
646 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
647 SMP-capable replacement for PC-style interrupt controllers. Most
648 SMP systems and many recent uniprocessor systems have one.
650 If you have a single-CPU system with an IO-APIC, you can say Y here
651 to use it. If you say Y here even though your machine doesn't have
652 an IO-APIC, then the kernel will still run with no slowdown at all.
654 config X86_LOCAL_APIC
656 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
660 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
662 config X86_VISWS_APIC
664 depends on X86_32 && X86_VISWS
667 bool "Machine Check Exception"
668 depends on !X86_VOYAGER
670 Machine Check Exception support allows the processor to notify the
671 kernel if it detects a problem (e.g. overheating, component failure).
672 The action the kernel takes depends on the severity of the problem,
673 ranging from a warning message on the console, to halting the machine.
674 Your processor must be a Pentium or newer to support this - check the
675 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
676 have a design flaw which leads to false MCE events - hence MCE is
677 disabled on all P5 processors, unless explicitly enabled with "mce"
678 as a boot argument. Similarly, if MCE is built in and creates a
679 problem on some new non-standard machine, you can boot with "nomce"
680 to disable it. MCE support simply ignores non-MCE processors like
681 the 386 and 486, so nearly everyone can say Y here.
685 prompt "Intel MCE features"
686 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
688 Additional support for intel specific MCE features such as
693 prompt "AMD MCE features"
694 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
696 Additional support for AMD specific MCE features such as
697 the DRAM Error Threshold.
699 config X86_MCE_NONFATAL
700 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
701 depends on X86_32 && X86_MCE
703 Enabling this feature starts a timer that triggers every 5 seconds which
704 will look at the machine check registers to see if anything happened.
705 Non-fatal problems automatically get corrected (but still logged).
706 Disable this if you don't want to see these messages.
707 Seeing the messages this option prints out may be indicative of dying
708 or out-of-spec (ie, overclocked) hardware.
709 This option only does something on certain CPUs.
710 (AMD Athlon/Duron and Intel Pentium 4)
712 config X86_MCE_P4THERMAL
713 bool "check for P4 thermal throttling interrupt."
714 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
716 Enabling this feature will cause a message to be printed when the P4
717 enters thermal throttling.
720 bool "Enable VM86 support" if EMBEDDED
724 This option is required by programs like DOSEMU to run 16-bit legacy
725 code on X86 processors. It also may be needed by software like
726 XFree86 to initialize some video cards via BIOS. Disabling this
727 option saves about 6k.
730 tristate "Toshiba Laptop support"
733 This adds a driver to safely access the System Management Mode of
734 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
735 not work on models with a Phoenix BIOS. The System Management Mode
736 is used to set the BIOS and power saving options on Toshiba portables.
738 For information on utilities to make use of this driver see the
739 Toshiba Linux utilities web site at:
740 <http://www.buzzard.org.uk/toshiba/>.
742 Say Y if you intend to run this kernel on a Toshiba portable.
746 tristate "Dell laptop support"
748 This adds a driver to safely access the System Management Mode
749 of the CPU on the Dell Inspiron 8000. The System Management Mode
750 is used to read cpu temperature and cooling fan status and to
751 control the fans on the I8K portables.
753 This driver has been tested only on the Inspiron 8000 but it may
754 also work with other Dell laptops. You can force loading on other
755 models by passing the parameter `force=1' to the module. Use at
758 For information on utilities to make use of this driver see the
759 I8K Linux utilities web site at:
760 <http://people.debian.org/~dz/i8k/>
762 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
765 config X86_REBOOTFIXUPS
766 bool "Enable X86 board specific fixups for reboot"
769 This enables chipset and/or board specific fixups to be done
770 in order to get reboot to work correctly. This is only needed on
771 some combinations of hardware and BIOS. The symptom, for which
772 this config is intended, is when reboot ends with a stalled/hung
775 Currently, the only fixup is for the Geode machines using
776 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
778 Say Y if you want to enable the fixup. Currently, it's safe to
779 enable this option even if you don't need it.
783 tristate "/dev/cpu/microcode - microcode support"
786 If you say Y here, you will be able to update the microcode on
787 certain Intel and AMD processors. The Intel support is for the
788 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
789 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
790 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
791 You will obviously need the actual microcode binary data itself
792 which is not shipped with the Linux kernel.
794 This option selects the general module only, you need to select
795 at least one vendor specific module as well.
797 To compile this driver as a module, choose M here: the
798 module will be called microcode.
800 config MICROCODE_INTEL
801 bool "Intel microcode patch loading support"
806 This options enables microcode patch loading support for Intel
809 For latest news and information on obtaining all the required
810 Intel ingredients for this driver, check:
811 <http://www.urbanmyth.org/microcode/>.
814 bool "AMD microcode patch loading support"
818 If you select this option, microcode patch loading support for AMD
819 processors will be enabled.
821 config MICROCODE_OLD_INTERFACE
826 tristate "/dev/cpu/*/msr - Model-specific register support"
828 This device gives privileged processes access to the x86
829 Model-Specific Registers (MSRs). It is a character device with
830 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
831 MSR accesses are directed to a specific CPU on multi-processor
835 tristate "/dev/cpu/*/cpuid - CPU information support"
837 This device gives processes access to the x86 CPUID instruction to
838 be executed on a specific processor. It is a character device
839 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
843 prompt "High Memory Support"
844 default HIGHMEM4G if !X86_NUMAQ
845 default HIGHMEM64G if X86_NUMAQ
850 depends on !X86_NUMAQ
852 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
853 However, the address space of 32-bit x86 processors is only 4
854 Gigabytes large. That means that, if you have a large amount of
855 physical memory, not all of it can be "permanently mapped" by the
856 kernel. The physical memory that's not permanently mapped is called
859 If you are compiling a kernel which will never run on a machine with
860 more than 1 Gigabyte total physical RAM, answer "off" here (default
861 choice and suitable for most users). This will result in a "3GB/1GB"
862 split: 3GB are mapped so that each process sees a 3GB virtual memory
863 space and the remaining part of the 4GB virtual memory space is used
864 by the kernel to permanently map as much physical memory as
867 If the machine has between 1 and 4 Gigabytes physical RAM, then
870 If more than 4 Gigabytes is used then answer "64GB" here. This
871 selection turns Intel PAE (Physical Address Extension) mode on.
872 PAE implements 3-level paging on IA32 processors. PAE is fully
873 supported by Linux, PAE mode is implemented on all recent Intel
874 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
875 then the kernel will not boot on CPUs that don't support PAE!
877 The actual amount of total physical memory will either be
878 auto detected or can be forced by using a kernel command line option
879 such as "mem=256M". (Try "man bootparam" or see the documentation of
880 your boot loader (lilo or loadlin) about how to pass options to the
881 kernel at boot time.)
883 If unsure, say "off".
887 depends on !X86_NUMAQ
889 Select this if you have a 32-bit processor and between 1 and 4
890 gigabytes of physical RAM.
894 depends on !M386 && !M486
897 Select this if you have a 32-bit processor and more than 4
898 gigabytes of physical RAM.
903 depends on EXPERIMENTAL
904 prompt "Memory split" if EMBEDDED
908 Select the desired split between kernel and user memory.
910 If the address range available to the kernel is less than the
911 physical memory installed, the remaining memory will be available
912 as "high memory". Accessing high memory is a little more costly
913 than low memory, as it needs to be mapped into the kernel first.
914 Note that increasing the kernel address space limits the range
915 available to user programs, making the address space there
916 tighter. Selecting anything other than the default 3G/1G split
917 will also likely make your kernel incompatible with binary-only
920 If you are not absolutely sure what you are doing, leave this
924 bool "3G/1G user/kernel split"
925 config VMSPLIT_3G_OPT
927 bool "3G/1G user/kernel split (for full 1G low memory)"
929 bool "2G/2G user/kernel split"
930 config VMSPLIT_2G_OPT
932 bool "2G/2G user/kernel split (for full 2G low memory)"
934 bool "1G/3G user/kernel split"
939 default 0xB0000000 if VMSPLIT_3G_OPT
940 default 0x80000000 if VMSPLIT_2G
941 default 0x78000000 if VMSPLIT_2G_OPT
942 default 0x40000000 if VMSPLIT_1G
948 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
951 bool "PAE (Physical Address Extension) Support"
952 depends on X86_32 && !HIGHMEM4G
954 PAE is required for NX support, and furthermore enables
955 larger swapspace support for non-overcommit purposes. It
956 has the cost of more pagetable lookup overhead, and also
957 consumes more pagetable space per process.
959 config ARCH_PHYS_ADDR_T_64BIT
960 def_bool X86_64 || X86_PAE
962 # Common NUMA Features
964 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
966 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
968 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
970 Enable NUMA (Non Uniform Memory Access) support.
971 The kernel will try to allocate memory used by a CPU on the
972 local memory controller of the CPU and add some more
973 NUMA awareness to the kernel.
975 For 32-bit this is currently highly experimental and should be only
976 used for kernel development. It might also cause boot failures.
977 For 64-bit this is recommended on all multiprocessor Opteron systems.
978 If the system is EM64T, you should say N unless your system is
981 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
982 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
986 prompt "Old style AMD Opteron NUMA detection"
987 depends on X86_64 && NUMA && PCI
989 Enable K8 NUMA node topology detection. You should say Y here if
990 you have a multi processor AMD K8 system. This uses an old
991 method to read the NUMA configuration directly from the builtin
992 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
993 instead, which also takes priority if both are compiled in.
995 config X86_64_ACPI_NUMA
997 prompt "ACPI NUMA detection"
998 depends on X86_64 && NUMA && ACPI && PCI
1001 Enable ACPI SRAT based node topology detection.
1003 # Some NUMA nodes have memory ranges that span
1004 # other nodes. Even though a pfn is valid and
1005 # between a node's start and end pfns, it may not
1006 # reside on that node. See memmap_init_zone()
1008 config NODES_SPAN_OTHER_NODES
1010 depends on X86_64_ACPI_NUMA
1013 bool "NUMA emulation"
1014 depends on X86_64 && NUMA
1016 Enable NUMA emulation. A flat machine will be split
1017 into virtual nodes when booted with "numa=fake=N", where N is the
1018 number of nodes. This is only useful for debugging.
1021 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1023 default "9" if MAXSMP
1024 default "6" if X86_64
1025 default "4" if X86_NUMAQ
1027 depends on NEED_MULTIPLE_NODES
1029 Specify the maximum number of NUMA Nodes available on the target
1030 system. Increases memory reserved to accomodate various tables.
1032 config HAVE_ARCH_BOOTMEM_NODE
1034 depends on X86_32 && NUMA
1036 config ARCH_HAVE_MEMORY_PRESENT
1038 depends on X86_32 && DISCONTIGMEM
1040 config NEED_NODE_MEMMAP_SIZE
1042 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1044 config HAVE_ARCH_ALLOC_REMAP
1046 depends on X86_32 && NUMA
1048 config ARCH_FLATMEM_ENABLE
1050 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1052 config ARCH_DISCONTIGMEM_ENABLE
1054 depends on NUMA && X86_32
1056 config ARCH_DISCONTIGMEM_DEFAULT
1058 depends on NUMA && X86_32
1060 config ARCH_SPARSEMEM_DEFAULT
1064 config ARCH_SPARSEMEM_ENABLE
1066 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1067 select SPARSEMEM_STATIC if X86_32
1068 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1070 config ARCH_SELECT_MEMORY_MODEL
1072 depends on ARCH_SPARSEMEM_ENABLE
1074 config ARCH_MEMORY_PROBE
1076 depends on MEMORY_HOTPLUG
1081 bool "Allocate 3rd-level pagetables from highmem"
1082 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1084 The VM uses one page table entry for each page of physical memory.
1085 For systems with a lot of RAM, this can be wasteful of precious
1086 low memory. Setting this option will put user-space page table
1087 entries in high memory.
1089 config X86_CHECK_BIOS_CORRUPTION
1090 bool "Check for low memory corruption"
1092 Periodically check for memory corruption in low memory, which
1093 is suspected to be caused by BIOS. Even when enabled in the
1094 configuration, it is disabled at runtime. Enable it by
1095 setting "memory_corruption_check=1" on the kernel command
1096 line. By default it scans the low 64k of memory every 60
1097 seconds; see the memory_corruption_check_size and
1098 memory_corruption_check_period parameters in
1099 Documentation/kernel-parameters.txt to adjust this.
1101 When enabled with the default parameters, this option has
1102 almost no overhead, as it reserves a relatively small amount
1103 of memory and scans it infrequently. It both detects corruption
1104 and prevents it from affecting the running system.
1106 It is, however, intended as a diagnostic tool; if repeatable
1107 BIOS-originated corruption always affects the same memory,
1108 you can use memmap= to prevent the kernel from using that
1111 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1112 bool "Set the default setting of memory_corruption_check"
1113 depends on X86_CHECK_BIOS_CORRUPTION
1116 Set whether the default state of memory_corruption_check is
1119 config X86_RESERVE_LOW_64K
1120 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1123 Reserve the first 64K of physical RAM on BIOSes that are known
1124 to potentially corrupt that memory range. A numbers of BIOSes are
1125 known to utilize this area during suspend/resume, so it must not
1126 be used by the kernel.
1128 Set this to N if you are absolutely sure that you trust the BIOS
1129 to get all its memory reservations and usages right.
1131 If you have doubts about the BIOS (e.g. suspend/resume does not
1132 work or there's kernel crashes after certain hardware hotplug
1133 events) and it's not AMI or Phoenix, then you might want to enable
1134 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1135 corruption patterns.
1139 config MATH_EMULATION
1141 prompt "Math emulation" if X86_32
1143 Linux can emulate a math coprocessor (used for floating point
1144 operations) if you don't have one. 486DX and Pentium processors have
1145 a math coprocessor built in, 486SX and 386 do not, unless you added
1146 a 487DX or 387, respectively. (The messages during boot time can
1147 give you some hints here ["man dmesg"].) Everyone needs either a
1148 coprocessor or this emulation.
1150 If you don't have a math coprocessor, you need to say Y here; if you
1151 say Y here even though you have a coprocessor, the coprocessor will
1152 be used nevertheless. (This behavior can be changed with the kernel
1153 command line option "no387", which comes handy if your coprocessor
1154 is broken. Try "man bootparam" or see the documentation of your boot
1155 loader (lilo or loadlin) about how to pass options to the kernel at
1156 boot time.) This means that it is a good idea to say Y here if you
1157 intend to use this kernel on different machines.
1159 More information about the internals of the Linux math coprocessor
1160 emulation can be found in <file:arch/x86/math-emu/README>.
1162 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1163 kernel, it won't hurt.
1166 bool "MTRR (Memory Type Range Register) support"
1168 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1169 the Memory Type Range Registers (MTRRs) may be used to control
1170 processor access to memory ranges. This is most useful if you have
1171 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1172 allows bus write transfers to be combined into a larger transfer
1173 before bursting over the PCI/AGP bus. This can increase performance
1174 of image write operations 2.5 times or more. Saying Y here creates a
1175 /proc/mtrr file which may be used to manipulate your processor's
1176 MTRRs. Typically the X server should use this.
1178 This code has a reasonably generic interface so that similar
1179 control registers on other processors can be easily supported
1182 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1183 Registers (ARRs) which provide a similar functionality to MTRRs. For
1184 these, the ARRs are used to emulate the MTRRs.
1185 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1186 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1187 write-combining. All of these processors are supported by this code
1188 and it makes sense to say Y here if you have one of them.
1190 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1191 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1192 can lead to all sorts of problems, so it's good to say Y here.
1194 You can safely say Y even if your machine doesn't have MTRRs, you'll
1195 just add about 9 KB to your kernel.
1197 See <file:Documentation/x86/mtrr.txt> for more information.
1199 config MTRR_SANITIZER
1201 prompt "MTRR cleanup support"
1204 Convert MTRR layout from continuous to discrete, so X drivers can
1205 add writeback entries.
1207 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1208 The largest mtrr entry size for a continous block can be set with
1213 config MTRR_SANITIZER_ENABLE_DEFAULT
1214 int "MTRR cleanup enable value (0-1)"
1217 depends on MTRR_SANITIZER
1219 Enable mtrr cleanup default value
1221 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1222 int "MTRR cleanup spare reg num (0-7)"
1225 depends on MTRR_SANITIZER
1227 mtrr cleanup spare entries default, it can be changed via
1228 mtrr_spare_reg_nr=N on the kernel command line.
1232 prompt "x86 PAT support"
1235 Use PAT attributes to setup page level cache control.
1237 PATs are the modern equivalents of MTRRs and are much more
1238 flexible than MTRRs.
1240 Say N here if you see bootup problems (boot crash, boot hang,
1241 spontaneous reboots) or a non-working video driver.
1246 bool "EFI runtime service support"
1249 This enables the kernel to use EFI runtime services that are
1250 available (such as the EFI variable services).
1252 This option is only useful on systems that have EFI firmware.
1253 In addition, you should use the latest ELILO loader available
1254 at <http://elilo.sourceforge.net> in order to take advantage
1255 of EFI runtime services. However, even with this option, the
1256 resultant kernel should continue to boot on existing non-EFI
1261 prompt "Enable seccomp to safely compute untrusted bytecode"
1263 This kernel feature is useful for number crunching applications
1264 that may need to compute untrusted bytecode during their
1265 execution. By using pipes or other transports made available to
1266 the process as file descriptors supporting the read/write
1267 syscalls, it's possible to isolate those applications in
1268 their own address space using seccomp. Once seccomp is
1269 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1270 and the task is only allowed to execute a few safe syscalls
1271 defined by each seccomp mode.
1273 If unsure, say Y. Only embedded should say N here.
1275 config CC_STACKPROTECTOR
1276 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1277 depends on X86_64 && EXPERIMENTAL && BROKEN
1279 This option turns on the -fstack-protector GCC feature. This
1280 feature puts, at the beginning of critical functions, a canary
1281 value on the stack just before the return address, and validates
1282 the value just before actually returning. Stack based buffer
1283 overflows (that need to overwrite this return address) now also
1284 overwrite the canary, which gets detected and the attack is then
1285 neutralized via a kernel panic.
1287 This feature requires gcc version 4.2 or above, or a distribution
1288 gcc with the feature backported. Older versions are automatically
1289 detected and for those versions, this configuration option is ignored.
1291 config CC_STACKPROTECTOR_ALL
1292 bool "Use stack-protector for all functions"
1293 depends on CC_STACKPROTECTOR
1295 Normally, GCC only inserts the canary value protection for
1296 functions that use large-ish on-stack buffers. By enabling
1297 this option, GCC will be asked to do this for ALL functions.
1299 source kernel/Kconfig.hz
1302 bool "kexec system call"
1303 depends on X86_BIOS_REBOOT
1305 kexec is a system call that implements the ability to shutdown your
1306 current kernel, and to start another kernel. It is like a reboot
1307 but it is independent of the system firmware. And like a reboot
1308 you can start any kernel with it, not just Linux.
1310 The name comes from the similarity to the exec system call.
1312 It is an ongoing process to be certain the hardware in a machine
1313 is properly shutdown, so do not be surprised if this code does not
1314 initially work for you. It may help to enable device hotplugging
1315 support. As of this writing the exact hardware interface is
1316 strongly in flux, so no good recommendation can be made.
1319 bool "kernel crash dumps"
1320 depends on X86_64 || (X86_32 && HIGHMEM)
1322 Generate crash dump after being started by kexec.
1323 This should be normally only set in special crash dump kernels
1324 which are loaded in the main kernel with kexec-tools into
1325 a specially reserved region and then later executed after
1326 a crash by kdump/kexec. The crash dump kernel must be compiled
1327 to a memory address not used by the main kernel or BIOS using
1328 PHYSICAL_START, or it must be built as a relocatable image
1329 (CONFIG_RELOCATABLE=y).
1330 For more details see Documentation/kdump/kdump.txt
1333 bool "kexec jump (EXPERIMENTAL)"
1334 depends on EXPERIMENTAL
1335 depends on KEXEC && HIBERNATION && X86_32
1337 Jump between original kernel and kexeced kernel and invoke
1338 code in physical address mode via KEXEC
1340 config PHYSICAL_START
1341 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1342 default "0x1000000" if X86_NUMAQ
1343 default "0x200000" if X86_64
1346 This gives the physical address where the kernel is loaded.
1348 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1349 bzImage will decompress itself to above physical address and
1350 run from there. Otherwise, bzImage will run from the address where
1351 it has been loaded by the boot loader and will ignore above physical
1354 In normal kdump cases one does not have to set/change this option
1355 as now bzImage can be compiled as a completely relocatable image
1356 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1357 address. This option is mainly useful for the folks who don't want
1358 to use a bzImage for capturing the crash dump and want to use a
1359 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1360 to be specifically compiled to run from a specific memory area
1361 (normally a reserved region) and this option comes handy.
1363 So if you are using bzImage for capturing the crash dump, leave
1364 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1365 Otherwise if you plan to use vmlinux for capturing the crash dump
1366 change this value to start of the reserved region (Typically 16MB
1367 0x1000000). In other words, it can be set based on the "X" value as
1368 specified in the "crashkernel=YM@XM" command line boot parameter
1369 passed to the panic-ed kernel. Typically this parameter is set as
1370 crashkernel=64M@16M. Please take a look at
1371 Documentation/kdump/kdump.txt for more details about crash dumps.
1373 Usage of bzImage for capturing the crash dump is recommended as
1374 one does not have to build two kernels. Same kernel can be used
1375 as production kernel and capture kernel. Above option should have
1376 gone away after relocatable bzImage support is introduced. But it
1377 is present because there are users out there who continue to use
1378 vmlinux for dump capture. This option should go away down the
1381 Don't change this unless you know what you are doing.
1384 bool "Build a relocatable kernel (EXPERIMENTAL)"
1385 depends on EXPERIMENTAL
1387 This builds a kernel image that retains relocation information
1388 so it can be loaded someplace besides the default 1MB.
1389 The relocations tend to make the kernel binary about 10% larger,
1390 but are discarded at runtime.
1392 One use is for the kexec on panic case where the recovery kernel
1393 must live at a different physical address than the primary
1396 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1397 it has been loaded at and the compile time physical address
1398 (CONFIG_PHYSICAL_START) is ignored.
1400 config PHYSICAL_ALIGN
1402 prompt "Alignment value to which kernel should be aligned" if X86_32
1403 default "0x100000" if X86_32
1404 default "0x200000" if X86_64
1405 range 0x2000 0x400000
1407 This value puts the alignment restrictions on physical address
1408 where kernel is loaded and run from. Kernel is compiled for an
1409 address which meets above alignment restriction.
1411 If bootloader loads the kernel at a non-aligned address and
1412 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1413 address aligned to above value and run from there.
1415 If bootloader loads the kernel at a non-aligned address and
1416 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1417 load address and decompress itself to the address it has been
1418 compiled for and run from there. The address for which kernel is
1419 compiled already meets above alignment restrictions. Hence the
1420 end result is that kernel runs from a physical address meeting
1421 above alignment restrictions.
1423 Don't change this unless you know what you are doing.
1426 bool "Support for hot-pluggable CPUs"
1427 depends on SMP && HOTPLUG && !X86_VOYAGER
1429 Say Y here to allow turning CPUs off and on. CPUs can be
1430 controlled through /sys/devices/system/cpu.
1431 ( Note: power management support will enable this option
1432 automatically on SMP systems. )
1433 Say N if you want to disable CPU hotplug.
1437 prompt "Compat VDSO support"
1438 depends on X86_32 || IA32_EMULATION
1440 Map the 32-bit VDSO to the predictable old-style address too.
1442 Say N here if you are running a sufficiently recent glibc
1443 version (2.3.3 or later), to remove the high-mapped
1444 VDSO mapping and to exclusively use the randomized VDSO.
1449 bool "Built-in kernel command line"
1452 Allow for specifying boot arguments to the kernel at
1453 build time. On some systems (e.g. embedded ones), it is
1454 necessary or convenient to provide some or all of the
1455 kernel boot arguments with the kernel itself (that is,
1456 to not rely on the boot loader to provide them.)
1458 To compile command line arguments into the kernel,
1459 set this option to 'Y', then fill in the
1460 the boot arguments in CONFIG_CMDLINE.
1462 Systems with fully functional boot loaders (i.e. non-embedded)
1463 should leave this option set to 'N'.
1466 string "Built-in kernel command string"
1467 depends on CMDLINE_BOOL
1470 Enter arguments here that should be compiled into the kernel
1471 image and used at boot time. If the boot loader provides a
1472 command line at boot time, it is appended to this string to
1473 form the full kernel command line, when the system boots.
1475 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1476 change this behavior.
1478 In most cases, the command line (whether built-in or provided
1479 by the boot loader) should specify the device for the root
1482 config CMDLINE_OVERRIDE
1483 bool "Built-in command line overrides boot loader arguments"
1485 depends on CMDLINE_BOOL
1487 Set this option to 'Y' to have the kernel ignore the boot loader
1488 command line, and use ONLY the built-in command line.
1490 This is used to work around broken boot loaders. This should
1491 be set to 'N' under normal conditions.
1495 config ARCH_ENABLE_MEMORY_HOTPLUG
1497 depends on X86_64 || (X86_32 && HIGHMEM)
1499 config HAVE_ARCH_EARLY_PFN_TO_NID
1503 menu "Power management and ACPI options"
1504 depends on !X86_VOYAGER
1506 config ARCH_HIBERNATION_HEADER
1508 depends on X86_64 && HIBERNATION
1510 source "kernel/power/Kconfig"
1512 source "drivers/acpi/Kconfig"
1517 depends on APM || APM_MODULE
1520 tristate "APM (Advanced Power Management) BIOS support"
1521 depends on X86_32 && PM_SLEEP
1523 APM is a BIOS specification for saving power using several different
1524 techniques. This is mostly useful for battery powered laptops with
1525 APM compliant BIOSes. If you say Y here, the system time will be
1526 reset after a RESUME operation, the /proc/apm device will provide
1527 battery status information, and user-space programs will receive
1528 notification of APM "events" (e.g. battery status change).
1530 If you select "Y" here, you can disable actual use of the APM
1531 BIOS by passing the "apm=off" option to the kernel at boot time.
1533 Note that the APM support is almost completely disabled for
1534 machines with more than one CPU.
1536 In order to use APM, you will need supporting software. For location
1537 and more information, read <file:Documentation/power/pm.txt> and the
1538 Battery Powered Linux mini-HOWTO, available from
1539 <http://www.tldp.org/docs.html#howto>.
1541 This driver does not spin down disk drives (see the hdparm(8)
1542 manpage ("man 8 hdparm") for that), and it doesn't turn off
1543 VESA-compliant "green" monitors.
1545 This driver does not support the TI 4000M TravelMate and the ACER
1546 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1547 desktop machines also don't have compliant BIOSes, and this driver
1548 may cause those machines to panic during the boot phase.
1550 Generally, if you don't have a battery in your machine, there isn't
1551 much point in using this driver and you should say N. If you get
1552 random kernel OOPSes or reboots that don't seem to be related to
1553 anything, try disabling/enabling this option (or disabling/enabling
1556 Some other things you should try when experiencing seemingly random,
1559 1) make sure that you have enough swap space and that it is
1561 2) pass the "no-hlt" option to the kernel
1562 3) switch on floating point emulation in the kernel and pass
1563 the "no387" option to the kernel
1564 4) pass the "floppy=nodma" option to the kernel
1565 5) pass the "mem=4M" option to the kernel (thereby disabling
1566 all but the first 4 MB of RAM)
1567 6) make sure that the CPU is not over clocked.
1568 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1569 8) disable the cache from your BIOS settings
1570 9) install a fan for the video card or exchange video RAM
1571 10) install a better fan for the CPU
1572 11) exchange RAM chips
1573 12) exchange the motherboard.
1575 To compile this driver as a module, choose M here: the
1576 module will be called apm.
1580 config APM_IGNORE_USER_SUSPEND
1581 bool "Ignore USER SUSPEND"
1583 This option will ignore USER SUSPEND requests. On machines with a
1584 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1585 series notebooks, it is necessary to say Y because of a BIOS bug.
1587 config APM_DO_ENABLE
1588 bool "Enable PM at boot time"
1590 Enable APM features at boot time. From page 36 of the APM BIOS
1591 specification: "When disabled, the APM BIOS does not automatically
1592 power manage devices, enter the Standby State, enter the Suspend
1593 State, or take power saving steps in response to CPU Idle calls."
1594 This driver will make CPU Idle calls when Linux is idle (unless this
1595 feature is turned off -- see "Do CPU IDLE calls", below). This
1596 should always save battery power, but more complicated APM features
1597 will be dependent on your BIOS implementation. You may need to turn
1598 this option off if your computer hangs at boot time when using APM
1599 support, or if it beeps continuously instead of suspending. Turn
1600 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1601 T400CDT. This is off by default since most machines do fine without
1605 bool "Make CPU Idle calls when idle"
1607 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1608 On some machines, this can activate improved power savings, such as
1609 a slowed CPU clock rate, when the machine is idle. These idle calls
1610 are made after the idle loop has run for some length of time (e.g.,
1611 333 mS). On some machines, this will cause a hang at boot time or
1612 whenever the CPU becomes idle. (On machines with more than one CPU,
1613 this option does nothing.)
1615 config APM_DISPLAY_BLANK
1616 bool "Enable console blanking using APM"
1618 Enable console blanking using the APM. Some laptops can use this to
1619 turn off the LCD backlight when the screen blanker of the Linux
1620 virtual console blanks the screen. Note that this is only used by
1621 the virtual console screen blanker, and won't turn off the backlight
1622 when using the X Window system. This also doesn't have anything to
1623 do with your VESA-compliant power-saving monitor. Further, this
1624 option doesn't work for all laptops -- it might not turn off your
1625 backlight at all, or it might print a lot of errors to the console,
1626 especially if you are using gpm.
1628 config APM_ALLOW_INTS
1629 bool "Allow interrupts during APM BIOS calls"
1631 Normally we disable external interrupts while we are making calls to
1632 the APM BIOS as a measure to lessen the effects of a badly behaving
1633 BIOS implementation. The BIOS should reenable interrupts if it
1634 needs to. Unfortunately, some BIOSes do not -- especially those in
1635 many of the newer IBM Thinkpads. If you experience hangs when you
1636 suspend, try setting this to Y. Otherwise, say N.
1638 config APM_REAL_MODE_POWER_OFF
1639 bool "Use real mode APM BIOS call to power off"
1641 Use real mode APM BIOS calls to switch off the computer. This is
1642 a work-around for a number of buggy BIOSes. Switch this option on if
1643 your computer crashes instead of powering off properly.
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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