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
32 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
33 select HAVE_ARCH_KGDB if !X86_VOYAGER
34 select HAVE_ARCH_TRACEHOOK
35 select HAVE_GENERIC_DMA_COHERENT if X86_32
36 select HAVE_EFFICIENT_UNALIGNED_ACCESS
40 default "arch/x86/configs/i386_defconfig" if X86_32
41 default "arch/x86/configs/x86_64_defconfig" if X86_64
46 config GENERIC_CMOS_UPDATE
49 config CLOCKSOURCE_WATCHDOG
52 config GENERIC_CLOCKEVENTS
55 config GENERIC_CLOCKEVENTS_BROADCAST
57 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
59 config LOCKDEP_SUPPORT
62 config STACKTRACE_SUPPORT
65 config HAVE_LATENCYTOP_SUPPORT
68 config FAST_CMPXCHG_LOCAL
81 config GENERIC_ISA_DMA
91 config GENERIC_HWEIGHT
97 config ARCH_MAY_HAVE_PC_FDC
100 config RWSEM_GENERIC_SPINLOCK
103 config RWSEM_XCHGADD_ALGORITHM
106 config ARCH_HAS_CPU_IDLE_WAIT
109 config GENERIC_CALIBRATE_DELAY
112 config GENERIC_TIME_VSYSCALL
116 config ARCH_HAS_CPU_RELAX
119 config ARCH_HAS_CACHE_LINE_SIZE
122 config HAVE_SETUP_PER_CPU_AREA
123 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
125 config HAVE_CPUMASK_OF_CPU_MAP
128 config ARCH_HIBERNATION_POSSIBLE
130 depends on !SMP || !X86_VOYAGER
132 config ARCH_SUSPEND_POSSIBLE
134 depends on !X86_VOYAGER
140 config ARCH_POPULATES_NODE_MAP
147 config ARCH_SUPPORTS_OPTIMIZED_INLINING
150 # Use the generic interrupt handling code in kernel/irq/:
151 config GENERIC_HARDIRQS
155 config GENERIC_IRQ_PROBE
159 config GENERIC_PENDING_IRQ
161 depends on GENERIC_HARDIRQS && SMP
166 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
167 select USE_GENERIC_SMP_HELPERS
172 depends on X86_32 && SMP
176 depends on X86_64 && SMP
181 depends on (X86_32 && !X86_VOYAGER) || X86_64
184 config X86_BIOS_REBOOT
186 depends on !X86_VOYAGER
189 config X86_TRAMPOLINE
191 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
196 source "init/Kconfig"
197 source "kernel/Kconfig.freezer"
199 menu "Processor type and features"
201 source "kernel/time/Kconfig"
204 bool "Symmetric multi-processing support"
206 This enables support for systems with more than one CPU. If you have
207 a system with only one CPU, like most personal computers, say N. If
208 you have a system with more than one CPU, say Y.
210 If you say N here, the kernel will run on single and multiprocessor
211 machines, but will use only one CPU of a multiprocessor machine. If
212 you say Y here, the kernel will run on many, but not all,
213 singleprocessor machines. On a singleprocessor machine, the kernel
214 will run faster if you say N here.
216 Note that if you say Y here and choose architecture "586" or
217 "Pentium" under "Processor family", the kernel will not work on 486
218 architectures. Similarly, multiprocessor kernels for the "PPro"
219 architecture may not work on all Pentium based boards.
221 People using multiprocessor machines who say Y here should also say
222 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
223 Management" code will be disabled if you say Y here.
225 See also <file:Documentation/i386/IO-APIC.txt>,
226 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
227 <http://www.tldp.org/docs.html#howto>.
229 If you don't know what to do here, say N.
231 config X86_FIND_SMP_CONFIG
233 depends on X86_MPPARSE || X86_VOYAGER
238 bool "Enable MPS table"
239 depends on X86_LOCAL_APIC
241 For old smp systems that do not have proper acpi support. Newer systems
242 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
248 depends on X86_LOCAL_APIC
252 prompt "Subarchitecture Type"
258 Choose this option if your computer is a standard PC or compatible.
264 Select this for an AMD Elan processor.
266 Do not use this option for K6/Athlon/Opteron processors!
268 If unsure, choose "PC-compatible" instead.
272 depends on X86_32 && (SMP || BROKEN) && !PCI
274 Voyager is an MCA-based 32-way capable SMP architecture proprietary
275 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
279 If you do not specifically know you have a Voyager based machine,
280 say N here, otherwise the kernel you build will not be bootable.
282 config X86_GENERICARCH
283 bool "Generic architecture"
286 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
287 subarchitectures. It is intended for a generic binary kernel.
288 if you select them all, kernel will probe it one by one. and will
294 bool "NUMAQ (IBM/Sequent)"
295 depends on SMP && X86_32 && PCI && X86_MPPARSE
298 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
299 NUMA multiquad box. This changes the way that processors are
300 bootstrapped, and uses Clustered Logical APIC addressing mode instead
301 of Flat Logical. You will need a new lynxer.elf file to flash your
302 firmware with - send email to <Martin.Bligh@us.ibm.com>.
305 bool "Summit/EXA (IBM x440)"
306 depends on X86_32 && SMP
308 This option is needed for IBM systems that use the Summit/EXA chipset.
309 In particular, it is needed for the x440.
312 bool "Support for Unisys ES7000 IA32 series"
313 depends on X86_32 && SMP
315 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
316 supposed to run on an IA32-based Unisys ES7000 system.
319 bool "Support for big SMP systems with more than 8 CPUs"
320 depends on X86_32 && SMP
322 This option is needed for the systems that have more than 8 CPUs
323 and if the system is not of any sub-arch type above.
328 bool "Support for ScaleMP vSMP"
330 depends on X86_64 && PCI
332 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
333 supposed to run on these EM64T-based machines. Only choose this option
334 if you have one of these machines.
339 bool "SGI 320/540 (Visual Workstation)"
340 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
342 The SGI Visual Workstation series is an IA32-based workstation
343 based on SGI systems chips with some legacy PC hardware attached.
345 Say Y here to create a kernel to run on the SGI 320 or 540.
347 A kernel compiled for the Visual Workstation will run on general
348 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
351 bool "RDC R-321x SoC"
354 select X86_REBOOTFIXUPS
356 This option is needed for RDC R-321x system-on-chip, also known
358 If you don't have one of these chips, you should say N here.
360 config SCHED_NO_NO_OMIT_FRAME_POINTER
362 prompt "Single-depth WCHAN output"
365 Calculate simpler /proc/<PID>/wchan values. If this option
366 is disabled then wchan values will recurse back to the
367 caller function. This provides more accurate wchan values,
368 at the expense of slightly more scheduling overhead.
370 If in doubt, say "Y".
372 menuconfig PARAVIRT_GUEST
373 bool "Paravirtualized guest support"
375 Say Y here to get to see options related to running Linux under
376 various hypervisors. This option alone does not add any kernel code.
378 If you say N, all options in this submenu will be skipped and disabled.
382 source "arch/x86/xen/Kconfig"
385 bool "VMI Guest support"
388 depends on !X86_VOYAGER
390 VMI provides a paravirtualized interface to the VMware ESX server
391 (it could be used by other hypervisors in theory too, but is not
392 at the moment), by linking the kernel to a GPL-ed ROM module
393 provided by the hypervisor.
396 bool "KVM paravirtualized clock"
398 select PARAVIRT_CLOCK
399 depends on !X86_VOYAGER
401 Turning on this option will allow you to run a paravirtualized clock
402 when running over the KVM hypervisor. Instead of relying on a PIT
403 (or probably other) emulation by the underlying device model, the host
404 provides the guest with timing infrastructure such as time of day, and
408 bool "KVM Guest support"
410 depends on !X86_VOYAGER
412 This option enables various optimizations for running under the KVM
415 source "arch/x86/lguest/Kconfig"
418 bool "Enable paravirtualization code"
419 depends on !X86_VOYAGER
421 This changes the kernel so it can modify itself when it is run
422 under a hypervisor, potentially improving performance significantly
423 over full virtualization. However, when run without a hypervisor
424 the kernel is theoretically slower and slightly larger.
426 config PARAVIRT_CLOCK
432 config PARAVIRT_DEBUG
433 bool "paravirt-ops debugging"
434 depends on PARAVIRT && DEBUG_KERNEL
436 Enable to debug paravirt_ops internals. Specifically, BUG if
437 a paravirt_op is missing when it is called.
442 This option adds a kernel parameter 'memtest', which allows memtest
444 memtest=0, mean disabled; -- default
445 memtest=1, mean do 1 test pattern;
447 memtest=4, mean do 4 test patterns.
448 If you are unsure how to answer this question, answer N.
450 config X86_SUMMIT_NUMA
452 depends on X86_32 && NUMA && X86_GENERICARCH
454 config X86_CYCLONE_TIMER
456 depends on X86_GENERICARCH
458 config ES7000_CLUSTERED_APIC
460 depends on SMP && X86_ES7000 && MPENTIUMIII
462 source "arch/x86/Kconfig.cpu"
466 prompt "HPET Timer Support" if X86_32
468 Use the IA-PC HPET (High Precision Event Timer) to manage
469 time in preference to the PIT and RTC, if a HPET is
471 HPET is the next generation timer replacing legacy 8254s.
472 The HPET provides a stable time base on SMP
473 systems, unlike the TSC, but it is more expensive to access,
474 as it is off-chip. You can find the HPET spec at
475 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
477 You can safely choose Y here. However, HPET will only be
478 activated if the platform and the BIOS support this feature.
479 Otherwise the 8254 will be used for timing services.
481 Choose N to continue using the legacy 8254 timer.
483 config HPET_EMULATE_RTC
485 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
487 # Mark as embedded because too many people got it wrong.
488 # The code disables itself when not needed.
491 bool "Enable DMI scanning" if EMBEDDED
493 Enabled scanning of DMI to identify machine quirks. Say Y
494 here unless you have verified that your setup is not
495 affected by entries in the DMI blacklist. Required by PNP
499 bool "GART IOMMU support" if EMBEDDED
503 depends on X86_64 && PCI
505 Support for full DMA access of devices with 32bit memory access only
506 on systems with more than 3GB. This is usually needed for USB,
507 sound, many IDE/SATA chipsets and some other devices.
508 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
509 based hardware IOMMU and a software bounce buffer based IOMMU used
510 on Intel systems and as fallback.
511 The code is only active when needed (enough memory and limited
512 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
516 bool "IBM Calgary IOMMU support"
518 depends on X86_64 && PCI && EXPERIMENTAL
520 Support for hardware IOMMUs in IBM's xSeries x366 and x460
521 systems. Needed to run systems with more than 3GB of memory
522 properly with 32-bit PCI devices that do not support DAC
523 (Double Address Cycle). Calgary also supports bus level
524 isolation, where all DMAs pass through the IOMMU. This
525 prevents them from going anywhere except their intended
526 destination. This catches hard-to-find kernel bugs and
527 mis-behaving drivers and devices that do not use the DMA-API
528 properly to set up their DMA buffers. The IOMMU can be
529 turned off at boot time with the iommu=off parameter.
530 Normally the kernel will make the right choice by itself.
533 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
535 prompt "Should Calgary be enabled by default?"
536 depends on CALGARY_IOMMU
538 Should Calgary be enabled by default? if you choose 'y', Calgary
539 will be used (if it exists). If you choose 'n', Calgary will not be
540 used even if it exists. If you choose 'n' and would like to use
541 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
545 bool "AMD IOMMU support"
548 depends on X86_64 && PCI && ACPI
550 With this option you can enable support for AMD IOMMU hardware in
551 your system. An IOMMU is a hardware component which provides
552 remapping of DMA memory accesses from devices. With an AMD IOMMU you
553 can isolate the the DMA memory of different devices and protect the
554 system from misbehaving device drivers or hardware.
556 You can find out if your system has an AMD IOMMU if you look into
557 your BIOS for an option to enable it or if you have an IVRS ACPI
560 # need this always selected by IOMMU for the VIA workaround
564 Support for software bounce buffers used on x86-64 systems
565 which don't have a hardware IOMMU (e.g. the current generation
566 of Intel's x86-64 CPUs). Using this PCI devices which can only
567 access 32-bits of memory can be used on systems with more than
568 3 GB of memory. If unsure, say Y.
571 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
574 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
575 depends on X86_64 && SMP && BROKEN
578 Configure maximum number of CPUS and NUMA Nodes for this architecture.
582 int "Maximum number of CPUs (2-512)" if !MAXSMP
585 default "4096" if MAXSMP
586 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
589 This allows you to specify the maximum number of CPUs which this
590 kernel will support. The maximum supported value is 512 and the
591 minimum value which makes sense is 2.
593 This is purely to save memory - each supported CPU adds
594 approximately eight kilobytes to the kernel image.
597 bool "SMT (Hyperthreading) scheduler support"
600 SMT scheduler support improves the CPU scheduler's decision making
601 when dealing with Intel Pentium 4 chips with HyperThreading at a
602 cost of slightly increased overhead in some places. If unsure say
607 prompt "Multi-core scheduler support"
610 Multi-core scheduler support improves the CPU scheduler's decision
611 making when dealing with multi-core CPU chips at a cost of slightly
612 increased overhead in some places. If unsure say N here.
614 source "kernel/Kconfig.preempt"
617 bool "Local APIC support on uniprocessors"
618 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
620 A local APIC (Advanced Programmable Interrupt Controller) is an
621 integrated interrupt controller in the CPU. If you have a single-CPU
622 system which has a processor with a local APIC, you can say Y here to
623 enable and use it. If you say Y here even though your machine doesn't
624 have a local APIC, then the kernel will still run with no slowdown at
625 all. The local APIC supports CPU-generated self-interrupts (timer,
626 performance counters), and the NMI watchdog which detects hard
630 bool "IO-APIC support on uniprocessors"
631 depends on X86_UP_APIC
633 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
634 SMP-capable replacement for PC-style interrupt controllers. Most
635 SMP systems and many recent uniprocessor systems have one.
637 If you have a single-CPU system with an IO-APIC, you can say Y here
638 to use it. If you say Y here even though your machine doesn't have
639 an IO-APIC, then the kernel will still run with no slowdown at all.
641 config X86_LOCAL_APIC
643 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
647 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
649 config X86_VISWS_APIC
651 depends on X86_32 && X86_VISWS
654 bool "Machine Check Exception"
655 depends on !X86_VOYAGER
657 Machine Check Exception support allows the processor to notify the
658 kernel if it detects a problem (e.g. overheating, component failure).
659 The action the kernel takes depends on the severity of the problem,
660 ranging from a warning message on the console, to halting the machine.
661 Your processor must be a Pentium or newer to support this - check the
662 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
663 have a design flaw which leads to false MCE events - hence MCE is
664 disabled on all P5 processors, unless explicitly enabled with "mce"
665 as a boot argument. Similarly, if MCE is built in and creates a
666 problem on some new non-standard machine, you can boot with "nomce"
667 to disable it. MCE support simply ignores non-MCE processors like
668 the 386 and 486, so nearly everyone can say Y here.
672 prompt "Intel MCE features"
673 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
675 Additional support for intel specific MCE features such as
680 prompt "AMD MCE features"
681 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
683 Additional support for AMD specific MCE features such as
684 the DRAM Error Threshold.
686 config X86_MCE_NONFATAL
687 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
688 depends on X86_32 && X86_MCE
690 Enabling this feature starts a timer that triggers every 5 seconds which
691 will look at the machine check registers to see if anything happened.
692 Non-fatal problems automatically get corrected (but still logged).
693 Disable this if you don't want to see these messages.
694 Seeing the messages this option prints out may be indicative of dying
695 or out-of-spec (ie, overclocked) hardware.
696 This option only does something on certain CPUs.
697 (AMD Athlon/Duron and Intel Pentium 4)
699 config X86_MCE_P4THERMAL
700 bool "check for P4 thermal throttling interrupt."
701 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
703 Enabling this feature will cause a message to be printed when the P4
704 enters thermal throttling.
707 bool "Enable VM86 support" if EMBEDDED
711 This option is required by programs like DOSEMU to run 16-bit legacy
712 code on X86 processors. It also may be needed by software like
713 XFree86 to initialize some video cards via BIOS. Disabling this
714 option saves about 6k.
717 tristate "Toshiba Laptop support"
720 This adds a driver to safely access the System Management Mode of
721 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
722 not work on models with a Phoenix BIOS. The System Management Mode
723 is used to set the BIOS and power saving options on Toshiba portables.
725 For information on utilities to make use of this driver see the
726 Toshiba Linux utilities web site at:
727 <http://www.buzzard.org.uk/toshiba/>.
729 Say Y if you intend to run this kernel on a Toshiba portable.
733 tristate "Dell laptop support"
735 This adds a driver to safely access the System Management Mode
736 of the CPU on the Dell Inspiron 8000. The System Management Mode
737 is used to read cpu temperature and cooling fan status and to
738 control the fans on the I8K portables.
740 This driver has been tested only on the Inspiron 8000 but it may
741 also work with other Dell laptops. You can force loading on other
742 models by passing the parameter `force=1' to the module. Use at
745 For information on utilities to make use of this driver see the
746 I8K Linux utilities web site at:
747 <http://people.debian.org/~dz/i8k/>
749 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
752 config X86_REBOOTFIXUPS
753 bool "Enable X86 board specific fixups for reboot"
756 This enables chipset and/or board specific fixups to be done
757 in order to get reboot to work correctly. This is only needed on
758 some combinations of hardware and BIOS. The symptom, for which
759 this config is intended, is when reboot ends with a stalled/hung
762 Currently, the only fixup is for the Geode machines using
763 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
765 Say Y if you want to enable the fixup. Currently, it's safe to
766 enable this option even if you don't need it.
770 tristate "/dev/cpu/microcode - microcode support"
773 If you say Y here, you will be able to update the microcode on
774 certain Intel and AMD processors. The Intel support is for the
775 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
776 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
777 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
778 You will obviously need the actual microcode binary data itself
779 which is not shipped with the Linux kernel.
781 This option selects the general module only, you need to select
782 at least one vendor specific module as well.
784 To compile this driver as a module, choose M here: the
785 module will be called microcode.
787 config MICROCODE_INTEL
788 bool "Intel microcode patch loading support"
793 This options enables microcode patch loading support for Intel
796 For latest news and information on obtaining all the required
797 Intel ingredients for this driver, check:
798 <http://www.urbanmyth.org/microcode/>.
801 bool "AMD microcode patch loading support"
805 If you select this option, microcode patch loading support for AMD
806 processors will be enabled.
808 config MICROCODE_OLD_INTERFACE
813 tristate "/dev/cpu/*/msr - Model-specific register support"
815 This device gives privileged processes access to the x86
816 Model-Specific Registers (MSRs). It is a character device with
817 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
818 MSR accesses are directed to a specific CPU on multi-processor
822 tristate "/dev/cpu/*/cpuid - CPU information support"
824 This device gives processes access to the x86 CPUID instruction to
825 be executed on a specific processor. It is a character device
826 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
830 prompt "High Memory Support"
831 default HIGHMEM4G if !X86_NUMAQ
832 default HIGHMEM64G if X86_NUMAQ
837 depends on !X86_NUMAQ
839 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
840 However, the address space of 32-bit x86 processors is only 4
841 Gigabytes large. That means that, if you have a large amount of
842 physical memory, not all of it can be "permanently mapped" by the
843 kernel. The physical memory that's not permanently mapped is called
846 If you are compiling a kernel which will never run on a machine with
847 more than 1 Gigabyte total physical RAM, answer "off" here (default
848 choice and suitable for most users). This will result in a "3GB/1GB"
849 split: 3GB are mapped so that each process sees a 3GB virtual memory
850 space and the remaining part of the 4GB virtual memory space is used
851 by the kernel to permanently map as much physical memory as
854 If the machine has between 1 and 4 Gigabytes physical RAM, then
857 If more than 4 Gigabytes is used then answer "64GB" here. This
858 selection turns Intel PAE (Physical Address Extension) mode on.
859 PAE implements 3-level paging on IA32 processors. PAE is fully
860 supported by Linux, PAE mode is implemented on all recent Intel
861 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
862 then the kernel will not boot on CPUs that don't support PAE!
864 The actual amount of total physical memory will either be
865 auto detected or can be forced by using a kernel command line option
866 such as "mem=256M". (Try "man bootparam" or see the documentation of
867 your boot loader (lilo or loadlin) about how to pass options to the
868 kernel at boot time.)
870 If unsure, say "off".
874 depends on !X86_NUMAQ
876 Select this if you have a 32-bit processor and between 1 and 4
877 gigabytes of physical RAM.
881 depends on !M386 && !M486
884 Select this if you have a 32-bit processor and more than 4
885 gigabytes of physical RAM.
890 depends on EXPERIMENTAL
891 prompt "Memory split" if EMBEDDED
895 Select the desired split between kernel and user memory.
897 If the address range available to the kernel is less than the
898 physical memory installed, the remaining memory will be available
899 as "high memory". Accessing high memory is a little more costly
900 than low memory, as it needs to be mapped into the kernel first.
901 Note that increasing the kernel address space limits the range
902 available to user programs, making the address space there
903 tighter. Selecting anything other than the default 3G/1G split
904 will also likely make your kernel incompatible with binary-only
907 If you are not absolutely sure what you are doing, leave this
911 bool "3G/1G user/kernel split"
912 config VMSPLIT_3G_OPT
914 bool "3G/1G user/kernel split (for full 1G low memory)"
916 bool "2G/2G user/kernel split"
917 config VMSPLIT_2G_OPT
919 bool "2G/2G user/kernel split (for full 2G low memory)"
921 bool "1G/3G user/kernel split"
926 default 0xB0000000 if VMSPLIT_3G_OPT
927 default 0x80000000 if VMSPLIT_2G
928 default 0x78000000 if VMSPLIT_2G_OPT
929 default 0x40000000 if VMSPLIT_1G
935 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
938 bool "PAE (Physical Address Extension) Support"
939 depends on X86_32 && !HIGHMEM4G
941 PAE is required for NX support, and furthermore enables
942 larger swapspace support for non-overcommit purposes. It
943 has the cost of more pagetable lookup overhead, and also
944 consumes more pagetable space per process.
946 config ARCH_PHYS_ADDR_T_64BIT
947 def_bool X86_64 || X86_PAE
949 # Common NUMA Features
951 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
953 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
955 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
957 Enable NUMA (Non Uniform Memory Access) support.
958 The kernel will try to allocate memory used by a CPU on the
959 local memory controller of the CPU and add some more
960 NUMA awareness to the kernel.
962 For 32-bit this is currently highly experimental and should be only
963 used for kernel development. It might also cause boot failures.
964 For 64-bit this is recommended on all multiprocessor Opteron systems.
965 If the system is EM64T, you should say N unless your system is
968 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
969 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
973 prompt "Old style AMD Opteron NUMA detection"
974 depends on X86_64 && NUMA && PCI
976 Enable K8 NUMA node topology detection. You should say Y here if
977 you have a multi processor AMD K8 system. This uses an old
978 method to read the NUMA configuration directly from the builtin
979 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
980 instead, which also takes priority if both are compiled in.
982 config X86_64_ACPI_NUMA
984 prompt "ACPI NUMA detection"
985 depends on X86_64 && NUMA && ACPI && PCI
988 Enable ACPI SRAT based node topology detection.
990 # Some NUMA nodes have memory ranges that span
991 # other nodes. Even though a pfn is valid and
992 # between a node's start and end pfns, it may not
993 # reside on that node. See memmap_init_zone()
995 config NODES_SPAN_OTHER_NODES
997 depends on X86_64_ACPI_NUMA
1000 bool "NUMA emulation"
1001 depends on X86_64 && NUMA
1003 Enable NUMA emulation. A flat machine will be split
1004 into virtual nodes when booted with "numa=fake=N", where N is the
1005 number of nodes. This is only useful for debugging.
1008 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1010 default "9" if MAXSMP
1011 default "6" if X86_64
1012 default "4" if X86_NUMAQ
1014 depends on NEED_MULTIPLE_NODES
1016 Specify the maximum number of NUMA Nodes available on the target
1017 system. Increases memory reserved to accomodate various tables.
1019 config HAVE_ARCH_BOOTMEM_NODE
1021 depends on X86_32 && NUMA
1023 config ARCH_HAVE_MEMORY_PRESENT
1025 depends on X86_32 && DISCONTIGMEM
1027 config NEED_NODE_MEMMAP_SIZE
1029 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1031 config HAVE_ARCH_ALLOC_REMAP
1033 depends on X86_32 && NUMA
1035 config ARCH_FLATMEM_ENABLE
1037 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1039 config ARCH_DISCONTIGMEM_ENABLE
1041 depends on NUMA && X86_32
1043 config ARCH_DISCONTIGMEM_DEFAULT
1045 depends on NUMA && X86_32
1047 config ARCH_SPARSEMEM_DEFAULT
1051 config ARCH_SPARSEMEM_ENABLE
1053 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1054 select SPARSEMEM_STATIC if X86_32
1055 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1057 config ARCH_SELECT_MEMORY_MODEL
1059 depends on ARCH_SPARSEMEM_ENABLE
1061 config ARCH_MEMORY_PROBE
1063 depends on MEMORY_HOTPLUG
1068 bool "Allocate 3rd-level pagetables from highmem"
1069 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1071 The VM uses one page table entry for each page of physical memory.
1072 For systems with a lot of RAM, this can be wasteful of precious
1073 low memory. Setting this option will put user-space page table
1074 entries in high memory.
1076 config X86_CHECK_BIOS_CORRUPTION
1077 bool "Check for low memory corruption"
1079 Periodically check for memory corruption in low memory, which
1080 is suspected to be caused by BIOS. Even when enabled in the
1081 configuration, it is disabled at runtime. Enable it by
1082 setting "memory_corruption_check=1" on the kernel command
1083 line. By default it scans the low 64k of memory every 60
1084 seconds; see the memory_corruption_check_size and
1085 memory_corruption_check_period parameters in
1086 Documentation/kernel-parameters.txt to adjust this.
1088 When enabled with the default parameters, this option has
1089 almost no overhead, as it reserves a relatively small amount
1090 of memory and scans it infrequently. It both detects corruption
1091 and prevents it from affecting the running system.
1093 It is, however, intended as a diagnostic tool; if repeatable
1094 BIOS-originated corruption always affects the same memory,
1095 you can use memmap= to prevent the kernel from using that
1098 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1099 bool "Set the default setting of memory_corruption_check"
1100 depends on X86_CHECK_BIOS_CORRUPTION
1103 Set whether the default state of memory_corruption_check is
1106 config X86_RESERVE_LOW_64K
1107 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1110 Reserve the first 64K of physical RAM on BIOSes that are known
1111 to potentially corrupt that memory range. A numbers of BIOSes are
1112 known to utilize this area during suspend/resume, so it must not
1113 be used by the kernel.
1115 Set this to N if you are absolutely sure that you trust the BIOS
1116 to get all its memory reservations and usages right.
1118 If you have doubts about the BIOS (e.g. suspend/resume does not
1119 work or there's kernel crashes after certain hardware hotplug
1120 events) and it's not AMI or Phoenix, then you might want to enable
1121 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1122 corruption patterns.
1126 config MATH_EMULATION
1128 prompt "Math emulation" if X86_32
1130 Linux can emulate a math coprocessor (used for floating point
1131 operations) if you don't have one. 486DX and Pentium processors have
1132 a math coprocessor built in, 486SX and 386 do not, unless you added
1133 a 487DX or 387, respectively. (The messages during boot time can
1134 give you some hints here ["man dmesg"].) Everyone needs either a
1135 coprocessor or this emulation.
1137 If you don't have a math coprocessor, you need to say Y here; if you
1138 say Y here even though you have a coprocessor, the coprocessor will
1139 be used nevertheless. (This behavior can be changed with the kernel
1140 command line option "no387", which comes handy if your coprocessor
1141 is broken. Try "man bootparam" or see the documentation of your boot
1142 loader (lilo or loadlin) about how to pass options to the kernel at
1143 boot time.) This means that it is a good idea to say Y here if you
1144 intend to use this kernel on different machines.
1146 More information about the internals of the Linux math coprocessor
1147 emulation can be found in <file:arch/x86/math-emu/README>.
1149 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1150 kernel, it won't hurt.
1153 bool "MTRR (Memory Type Range Register) support"
1155 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1156 the Memory Type Range Registers (MTRRs) may be used to control
1157 processor access to memory ranges. This is most useful if you have
1158 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1159 allows bus write transfers to be combined into a larger transfer
1160 before bursting over the PCI/AGP bus. This can increase performance
1161 of image write operations 2.5 times or more. Saying Y here creates a
1162 /proc/mtrr file which may be used to manipulate your processor's
1163 MTRRs. Typically the X server should use this.
1165 This code has a reasonably generic interface so that similar
1166 control registers on other processors can be easily supported
1169 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1170 Registers (ARRs) which provide a similar functionality to MTRRs. For
1171 these, the ARRs are used to emulate the MTRRs.
1172 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1173 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1174 write-combining. All of these processors are supported by this code
1175 and it makes sense to say Y here if you have one of them.
1177 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1178 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1179 can lead to all sorts of problems, so it's good to say Y here.
1181 You can safely say Y even if your machine doesn't have MTRRs, you'll
1182 just add about 9 KB to your kernel.
1184 See <file:Documentation/x86/mtrr.txt> for more information.
1186 config MTRR_SANITIZER
1188 prompt "MTRR cleanup support"
1191 Convert MTRR layout from continuous to discrete, so X drivers can
1192 add writeback entries.
1194 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1195 The largest mtrr entry size for a continous block can be set with
1200 config MTRR_SANITIZER_ENABLE_DEFAULT
1201 int "MTRR cleanup enable value (0-1)"
1204 depends on MTRR_SANITIZER
1206 Enable mtrr cleanup default value
1208 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1209 int "MTRR cleanup spare reg num (0-7)"
1212 depends on MTRR_SANITIZER
1214 mtrr cleanup spare entries default, it can be changed via
1215 mtrr_spare_reg_nr=N on the kernel command line.
1219 prompt "x86 PAT support"
1222 Use PAT attributes to setup page level cache control.
1224 PATs are the modern equivalents of MTRRs and are much more
1225 flexible than MTRRs.
1227 Say N here if you see bootup problems (boot crash, boot hang,
1228 spontaneous reboots) or a non-working video driver.
1233 bool "EFI runtime service support"
1236 This enables the kernel to use EFI runtime services that are
1237 available (such as the EFI variable services).
1239 This option is only useful on systems that have EFI firmware.
1240 In addition, you should use the latest ELILO loader available
1241 at <http://elilo.sourceforge.net> in order to take advantage
1242 of EFI runtime services. However, even with this option, the
1243 resultant kernel should continue to boot on existing non-EFI
1248 prompt "Enable seccomp to safely compute untrusted bytecode"
1250 This kernel feature is useful for number crunching applications
1251 that may need to compute untrusted bytecode during their
1252 execution. By using pipes or other transports made available to
1253 the process as file descriptors supporting the read/write
1254 syscalls, it's possible to isolate those applications in
1255 their own address space using seccomp. Once seccomp is
1256 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1257 and the task is only allowed to execute a few safe syscalls
1258 defined by each seccomp mode.
1260 If unsure, say Y. Only embedded should say N here.
1262 config CC_STACKPROTECTOR
1263 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1264 depends on X86_64 && EXPERIMENTAL && BROKEN
1266 This option turns on the -fstack-protector GCC feature. This
1267 feature puts, at the beginning of critical functions, a canary
1268 value on the stack just before the return address, and validates
1269 the value just before actually returning. Stack based buffer
1270 overflows (that need to overwrite this return address) now also
1271 overwrite the canary, which gets detected and the attack is then
1272 neutralized via a kernel panic.
1274 This feature requires gcc version 4.2 or above, or a distribution
1275 gcc with the feature backported. Older versions are automatically
1276 detected and for those versions, this configuration option is ignored.
1278 config CC_STACKPROTECTOR_ALL
1279 bool "Use stack-protector for all functions"
1280 depends on CC_STACKPROTECTOR
1282 Normally, GCC only inserts the canary value protection for
1283 functions that use large-ish on-stack buffers. By enabling
1284 this option, GCC will be asked to do this for ALL functions.
1286 source kernel/Kconfig.hz
1289 bool "kexec system call"
1290 depends on X86_BIOS_REBOOT
1292 kexec is a system call that implements the ability to shutdown your
1293 current kernel, and to start another kernel. It is like a reboot
1294 but it is independent of the system firmware. And like a reboot
1295 you can start any kernel with it, not just Linux.
1297 The name comes from the similarity to the exec system call.
1299 It is an ongoing process to be certain the hardware in a machine
1300 is properly shutdown, so do not be surprised if this code does not
1301 initially work for you. It may help to enable device hotplugging
1302 support. As of this writing the exact hardware interface is
1303 strongly in flux, so no good recommendation can be made.
1306 bool "kernel crash dumps"
1307 depends on X86_64 || (X86_32 && HIGHMEM)
1309 Generate crash dump after being started by kexec.
1310 This should be normally only set in special crash dump kernels
1311 which are loaded in the main kernel with kexec-tools into
1312 a specially reserved region and then later executed after
1313 a crash by kdump/kexec. The crash dump kernel must be compiled
1314 to a memory address not used by the main kernel or BIOS using
1315 PHYSICAL_START, or it must be built as a relocatable image
1316 (CONFIG_RELOCATABLE=y).
1317 For more details see Documentation/kdump/kdump.txt
1320 bool "kexec jump (EXPERIMENTAL)"
1321 depends on EXPERIMENTAL
1322 depends on KEXEC && HIBERNATION && X86_32
1324 Jump between original kernel and kexeced kernel and invoke
1325 code in physical address mode via KEXEC
1327 config PHYSICAL_START
1328 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1329 default "0x1000000" if X86_NUMAQ
1330 default "0x200000" if X86_64
1333 This gives the physical address where the kernel is loaded.
1335 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1336 bzImage will decompress itself to above physical address and
1337 run from there. Otherwise, bzImage will run from the address where
1338 it has been loaded by the boot loader and will ignore above physical
1341 In normal kdump cases one does not have to set/change this option
1342 as now bzImage can be compiled as a completely relocatable image
1343 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1344 address. This option is mainly useful for the folks who don't want
1345 to use a bzImage for capturing the crash dump and want to use a
1346 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1347 to be specifically compiled to run from a specific memory area
1348 (normally a reserved region) and this option comes handy.
1350 So if you are using bzImage for capturing the crash dump, leave
1351 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1352 Otherwise if you plan to use vmlinux for capturing the crash dump
1353 change this value to start of the reserved region (Typically 16MB
1354 0x1000000). In other words, it can be set based on the "X" value as
1355 specified in the "crashkernel=YM@XM" command line boot parameter
1356 passed to the panic-ed kernel. Typically this parameter is set as
1357 crashkernel=64M@16M. Please take a look at
1358 Documentation/kdump/kdump.txt for more details about crash dumps.
1360 Usage of bzImage for capturing the crash dump is recommended as
1361 one does not have to build two kernels. Same kernel can be used
1362 as production kernel and capture kernel. Above option should have
1363 gone away after relocatable bzImage support is introduced. But it
1364 is present because there are users out there who continue to use
1365 vmlinux for dump capture. This option should go away down the
1368 Don't change this unless you know what you are doing.
1371 bool "Build a relocatable kernel (EXPERIMENTAL)"
1372 depends on EXPERIMENTAL
1374 This builds a kernel image that retains relocation information
1375 so it can be loaded someplace besides the default 1MB.
1376 The relocations tend to make the kernel binary about 10% larger,
1377 but are discarded at runtime.
1379 One use is for the kexec on panic case where the recovery kernel
1380 must live at a different physical address than the primary
1383 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1384 it has been loaded at and the compile time physical address
1385 (CONFIG_PHYSICAL_START) is ignored.
1387 config PHYSICAL_ALIGN
1389 prompt "Alignment value to which kernel should be aligned" if X86_32
1390 default "0x100000" if X86_32
1391 default "0x200000" if X86_64
1392 range 0x2000 0x400000
1394 This value puts the alignment restrictions on physical address
1395 where kernel is loaded and run from. Kernel is compiled for an
1396 address which meets above alignment restriction.
1398 If bootloader loads the kernel at a non-aligned address and
1399 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1400 address aligned to above value and run from there.
1402 If bootloader loads the kernel at a non-aligned address and
1403 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1404 load address and decompress itself to the address it has been
1405 compiled for and run from there. The address for which kernel is
1406 compiled already meets above alignment restrictions. Hence the
1407 end result is that kernel runs from a physical address meeting
1408 above alignment restrictions.
1410 Don't change this unless you know what you are doing.
1413 bool "Support for hot-pluggable CPUs"
1414 depends on SMP && HOTPLUG && !X86_VOYAGER
1416 Say Y here to allow turning CPUs off and on. CPUs can be
1417 controlled through /sys/devices/system/cpu.
1418 ( Note: power management support will enable this option
1419 automatically on SMP systems. )
1420 Say N if you want to disable CPU hotplug.
1424 prompt "Compat VDSO support"
1425 depends on X86_32 || IA32_EMULATION
1427 Map the 32-bit VDSO to the predictable old-style address too.
1429 Say N here if you are running a sufficiently recent glibc
1430 version (2.3.3 or later), to remove the high-mapped
1431 VDSO mapping and to exclusively use the randomized VDSO.
1436 bool "Built-in kernel command line"
1439 Allow for specifying boot arguments to the kernel at
1440 build time. On some systems (e.g. embedded ones), it is
1441 necessary or convenient to provide some or all of the
1442 kernel boot arguments with the kernel itself (that is,
1443 to not rely on the boot loader to provide them.)
1445 To compile command line arguments into the kernel,
1446 set this option to 'Y', then fill in the
1447 the boot arguments in CONFIG_CMDLINE.
1449 Systems with fully functional boot loaders (i.e. non-embedded)
1450 should leave this option set to 'N'.
1453 string "Built-in kernel command string"
1454 depends on CMDLINE_BOOL
1457 Enter arguments here that should be compiled into the kernel
1458 image and used at boot time. If the boot loader provides a
1459 command line at boot time, it is appended to this string to
1460 form the full kernel command line, when the system boots.
1462 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1463 change this behavior.
1465 In most cases, the command line (whether built-in or provided
1466 by the boot loader) should specify the device for the root
1469 config CMDLINE_OVERRIDE
1470 bool "Built-in command line overrides boot loader arguments"
1472 depends on CMDLINE_BOOL
1474 Set this option to 'Y' to have the kernel ignore the boot loader
1475 command line, and use ONLY the built-in command line.
1477 This is used to work around broken boot loaders. This should
1478 be set to 'N' under normal conditions.
1482 config ARCH_ENABLE_MEMORY_HOTPLUG
1484 depends on X86_64 || (X86_32 && HIGHMEM)
1486 config HAVE_ARCH_EARLY_PFN_TO_NID
1490 menu "Power management options"
1491 depends on !X86_VOYAGER
1493 config ARCH_HIBERNATION_HEADER
1495 depends on X86_64 && HIBERNATION
1497 source "kernel/power/Kconfig"
1499 source "drivers/acpi/Kconfig"
1504 depends on APM || APM_MODULE
1507 tristate "APM (Advanced Power Management) BIOS support"
1508 depends on X86_32 && PM_SLEEP
1510 APM is a BIOS specification for saving power using several different
1511 techniques. This is mostly useful for battery powered laptops with
1512 APM compliant BIOSes. If you say Y here, the system time will be
1513 reset after a RESUME operation, the /proc/apm device will provide
1514 battery status information, and user-space programs will receive
1515 notification of APM "events" (e.g. battery status change).
1517 If you select "Y" here, you can disable actual use of the APM
1518 BIOS by passing the "apm=off" option to the kernel at boot time.
1520 Note that the APM support is almost completely disabled for
1521 machines with more than one CPU.
1523 In order to use APM, you will need supporting software. For location
1524 and more information, read <file:Documentation/power/pm.txt> and the
1525 Battery Powered Linux mini-HOWTO, available from
1526 <http://www.tldp.org/docs.html#howto>.
1528 This driver does not spin down disk drives (see the hdparm(8)
1529 manpage ("man 8 hdparm") for that), and it doesn't turn off
1530 VESA-compliant "green" monitors.
1532 This driver does not support the TI 4000M TravelMate and the ACER
1533 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1534 desktop machines also don't have compliant BIOSes, and this driver
1535 may cause those machines to panic during the boot phase.
1537 Generally, if you don't have a battery in your machine, there isn't
1538 much point in using this driver and you should say N. If you get
1539 random kernel OOPSes or reboots that don't seem to be related to
1540 anything, try disabling/enabling this option (or disabling/enabling
1543 Some other things you should try when experiencing seemingly random,
1546 1) make sure that you have enough swap space and that it is
1548 2) pass the "no-hlt" option to the kernel
1549 3) switch on floating point emulation in the kernel and pass
1550 the "no387" option to the kernel
1551 4) pass the "floppy=nodma" option to the kernel
1552 5) pass the "mem=4M" option to the kernel (thereby disabling
1553 all but the first 4 MB of RAM)
1554 6) make sure that the CPU is not over clocked.
1555 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1556 8) disable the cache from your BIOS settings
1557 9) install a fan for the video card or exchange video RAM
1558 10) install a better fan for the CPU
1559 11) exchange RAM chips
1560 12) exchange the motherboard.
1562 To compile this driver as a module, choose M here: the
1563 module will be called apm.
1567 config APM_IGNORE_USER_SUSPEND
1568 bool "Ignore USER SUSPEND"
1570 This option will ignore USER SUSPEND requests. On machines with a
1571 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1572 series notebooks, it is necessary to say Y because of a BIOS bug.
1574 config APM_DO_ENABLE
1575 bool "Enable PM at boot time"
1577 Enable APM features at boot time. From page 36 of the APM BIOS
1578 specification: "When disabled, the APM BIOS does not automatically
1579 power manage devices, enter the Standby State, enter the Suspend
1580 State, or take power saving steps in response to CPU Idle calls."
1581 This driver will make CPU Idle calls when Linux is idle (unless this
1582 feature is turned off -- see "Do CPU IDLE calls", below). This
1583 should always save battery power, but more complicated APM features
1584 will be dependent on your BIOS implementation. You may need to turn
1585 this option off if your computer hangs at boot time when using APM
1586 support, or if it beeps continuously instead of suspending. Turn
1587 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1588 T400CDT. This is off by default since most machines do fine without
1592 bool "Make CPU Idle calls when idle"
1594 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1595 On some machines, this can activate improved power savings, such as
1596 a slowed CPU clock rate, when the machine is idle. These idle calls
1597 are made after the idle loop has run for some length of time (e.g.,
1598 333 mS). On some machines, this will cause a hang at boot time or
1599 whenever the CPU becomes idle. (On machines with more than one CPU,
1600 this option does nothing.)
1602 config APM_DISPLAY_BLANK
1603 bool "Enable console blanking using APM"
1605 Enable console blanking using the APM. Some laptops can use this to
1606 turn off the LCD backlight when the screen blanker of the Linux
1607 virtual console blanks the screen. Note that this is only used by
1608 the virtual console screen blanker, and won't turn off the backlight
1609 when using the X Window system. This also doesn't have anything to
1610 do with your VESA-compliant power-saving monitor. Further, this
1611 option doesn't work for all laptops -- it might not turn off your
1612 backlight at all, or it might print a lot of errors to the console,
1613 especially if you are using gpm.
1615 config APM_ALLOW_INTS
1616 bool "Allow interrupts during APM BIOS calls"
1618 Normally we disable external interrupts while we are making calls to
1619 the APM BIOS as a measure to lessen the effects of a badly behaving
1620 BIOS implementation. The BIOS should reenable interrupts if it
1621 needs to. Unfortunately, some BIOSes do not -- especially those in
1622 many of the newer IBM Thinkpads. If you experience hangs when you
1623 suspend, try setting this to Y. Otherwise, say N.
1625 config APM_REAL_MODE_POWER_OFF
1626 bool "Use real mode APM BIOS call to power off"
1628 Use real mode APM BIOS calls to switch off the computer. This is
1629 a work-around for a number of buggy BIOSes. Switch this option on if
1630 your computer crashes instead of powering off properly.
1634 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1636 source "drivers/cpuidle/Kconfig"
1641 menu "Bus options (PCI etc.)"
1646 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1648 Find out whether you have a PCI motherboard. PCI is the name of a
1649 bus system, i.e. the way the CPU talks to the other stuff inside
1650 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1651 VESA. If you have PCI, say Y, otherwise N.
1654 prompt "PCI access mode"
1655 depends on X86_32 && PCI
1658 On PCI systems, the BIOS can be used to detect the PCI devices and
1659 determine their configuration. However, some old PCI motherboards
1660 have BIOS bugs and may crash if this is done. Also, some embedded
1661 PCI-based systems don't have any BIOS at all. Linux can also try to
1662 detect the PCI hardware directly without using the BIOS.
1664 With this option, you can specify how Linux should detect the
1665 PCI devices. If you choose "BIOS", the BIOS will be used,
1666 if you choose "Direct", the BIOS won't be used, and if you
1667 choose "MMConfig", then PCI Express MMCONFIG will be used.
1668 If you choose "Any", the kernel will try MMCONFIG, then the
1669 direct access method and falls back to the BIOS if that doesn't
1670 work. If unsure, go with the default, which is "Any".
1675 config PCI_GOMMCONFIG
1692 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1694 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1697 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1701 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1705 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1712 bool "Support mmconfig PCI config space access"
1713 depends on X86_64 && PCI && ACPI
1716 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1717 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1719 DMA remapping (DMAR) devices support enables independent address
1720 translations for Direct Memory Access (DMA) from devices.
1721 These DMA remapping devices are reported via ACPI tables
1722 and include PCI device scope covered by these DMA
1727 prompt "Support for Graphics workaround"
1730 Current Graphics drivers tend to use physical address
1731 for DMA and avoid using DMA APIs. Setting this config
1732 option permits the IOMMU driver to set a unity map for
1733 all the OS-visible memory. Hence the driver can continue
1734 to use physical addresses for DMA.
1736 config DMAR_FLOPPY_WA
1740 Floppy disk drivers are know to bypass DMA API calls
1741 thereby failing to work when IOMMU is enabled. This
1742 workaround will setup a 1:1 mapping for the first
1743 16M to make floppy (an ISA device) work.
1746 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1747 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1749 Supports Interrupt remapping for IO-APIC and MSI devices.
1750 To use x2apic mode in the CPU's which support x2APIC enhancements or
1751 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1753 source "drivers/pci/pcie/Kconfig"
1755 source "drivers/pci/Kconfig"
1757 # x86_64 have no ISA slots, but do have ISA-style DMA.
1765 depends on !X86_VOYAGER
1767 Find out whether you have ISA slots on your motherboard. ISA is the
1768 name of a bus system, i.e. the way the CPU talks to the other stuff
1769 inside your box. Other bus systems are PCI, EISA, MicroChannel
1770 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1771 newer boards don't support it. If you have ISA, say Y, otherwise N.
1777 The Extended Industry Standard Architecture (EISA) bus was
1778 developed as an open alternative to the IBM MicroChannel bus.
1780 The EISA bus provided some of the features of the IBM MicroChannel
1781 bus while maintaining backward compatibility with cards made for
1782 the older ISA bus. The EISA bus saw limited use between 1988 and
1783 1995 when it was made obsolete by the PCI bus.
1785 Say Y here if you are building a kernel for an EISA-based machine.
1789 source "drivers/eisa/Kconfig"
1792 bool "MCA support" if !X86_VOYAGER
1793 default y if X86_VOYAGER
1795 MicroChannel Architecture is found in some IBM PS/2 machines and
1796 laptops. It is a bus system similar to PCI or ISA. See
1797 <file:Documentation/mca.txt> (and especially the web page given
1798 there) before attempting to build an MCA bus kernel.
1800 source "drivers/mca/Kconfig"
1803 tristate "NatSemi SCx200 support"
1804 depends on !X86_VOYAGER
1806 This provides basic support for National Semiconductor's
1807 (now AMD's) Geode processors. The driver probes for the
1808 PCI-IDs of several on-chip devices, so its a good dependency
1809 for other scx200_* drivers.
1811 If compiled as a module, the driver is named scx200.
1813 config SCx200HR_TIMER
1814 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1815 depends on SCx200 && GENERIC_TIME
1818 This driver provides a clocksource built upon the on-chip
1819 27MHz high-resolution timer. Its also a workaround for
1820 NSC Geode SC-1100's buggy TSC, which loses time when the
1821 processor goes idle (as is done by the scheduler). The
1822 other workaround is idle=poll boot option.
1824 config GEODE_MFGPT_TIMER
1826 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1827 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1829 This driver provides a clock event source based on the MFGPT
1830 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1831 MFGPTs have a better resolution and max interval than the
1832 generic PIT, and are suitable for use as high-res timers.
1835 bool "One Laptop Per Child support"
1838 Add support for detecting the unique features of the OLPC
1845 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1847 source "drivers/pcmcia/Kconfig"
1849 source "drivers/pci/hotplug/Kconfig"
1854 menu "Executable file formats / Emulations"
1856 source "fs/Kconfig.binfmt"
1858 config IA32_EMULATION
1859 bool "IA32 Emulation"
1861 select COMPAT_BINFMT_ELF
1863 Include code to run 32-bit programs under a 64-bit kernel. You should
1864 likely turn this on, unless you're 100% sure that you don't have any
1865 32-bit programs left.
1868 tristate "IA32 a.out support"
1869 depends on IA32_EMULATION
1871 Support old a.out binaries in the 32bit emulation.
1875 depends on IA32_EMULATION
1877 config COMPAT_FOR_U64_ALIGNMENT
1881 config SYSVIPC_COMPAT
1883 depends on COMPAT && SYSVIPC
1888 source "net/Kconfig"
1890 source "drivers/Kconfig"
1892 source "drivers/firmware/Kconfig"
1896 source "arch/x86/Kconfig.debug"
1898 source "security/Kconfig"
1900 source "crypto/Kconfig"
1902 source "arch/x86/kvm/Kconfig"
1904 source "lib/Kconfig"
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