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_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_DEFAULT_IDLE
122 config ARCH_HAS_CACHE_LINE_SIZE
125 config HAVE_SETUP_PER_CPU_AREA
126 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
128 config HAVE_CPUMASK_OF_CPU_MAP
131 config ARCH_HIBERNATION_POSSIBLE
133 depends on !SMP || !X86_VOYAGER
135 config ARCH_SUSPEND_POSSIBLE
137 depends on !X86_VOYAGER
143 config ARCH_POPULATES_NODE_MAP
150 config ARCH_SUPPORTS_OPTIMIZED_INLINING
153 # Use the generic interrupt handling code in kernel/irq/:
154 config GENERIC_HARDIRQS
158 config GENERIC_IRQ_PROBE
162 config GENERIC_PENDING_IRQ
164 depends on GENERIC_HARDIRQS && SMP
169 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
172 config USE_GENERIC_SMP_HELPERS
178 depends on X86_32 && SMP
182 depends on X86_64 && SMP
187 depends on (X86_32 && !X86_VOYAGER) || X86_64
190 config X86_BIOS_REBOOT
192 depends on !X86_VOYAGER
195 config X86_TRAMPOLINE
197 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
202 source "init/Kconfig"
203 source "kernel/Kconfig.freezer"
205 menu "Processor type and features"
207 source "kernel/time/Kconfig"
210 bool "Symmetric multi-processing support"
212 This enables support for systems with more than one CPU. If you have
213 a system with only one CPU, like most personal computers, say N. If
214 you have a system with more than one CPU, say Y.
216 If you say N here, the kernel will run on single and multiprocessor
217 machines, but will use only one CPU of a multiprocessor machine. If
218 you say Y here, the kernel will run on many, but not all,
219 singleprocessor machines. On a singleprocessor machine, the kernel
220 will run faster if you say N here.
222 Note that if you say Y here and choose architecture "586" or
223 "Pentium" under "Processor family", the kernel will not work on 486
224 architectures. Similarly, multiprocessor kernels for the "PPro"
225 architecture may not work on all Pentium based boards.
227 People using multiprocessor machines who say Y here should also say
228 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
229 Management" code will be disabled if you say Y here.
231 See also <file:Documentation/i386/IO-APIC.txt>,
232 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
233 <http://www.tldp.org/docs.html#howto>.
235 If you don't know what to do here, say N.
237 config X86_HAS_BOOT_CPU_ID
239 depends on X86_VOYAGER
242 bool "Support sparse irq numbering"
243 depends on PCI_MSI || HT_IRQ
245 This enables support for sparse irqs. This is useful for distro
246 kernels that want to define a high CONFIG_NR_CPUS value but still
247 want to have low kernel memory footprint on smaller machines.
249 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
250 out the irq_desc[] array in a more NUMA-friendly way. )
252 If you don't know what to do here, say N.
254 config NUMA_MIGRATE_IRQ_DESC
255 bool "Move irq desc when changing irq smp_affinity"
256 depends on SPARSE_IRQ && NUMA
259 This enables moving irq_desc to cpu/node that irq will use handled.
261 If you don't know what to do here, say N.
263 config X86_FIND_SMP_CONFIG
265 depends on X86_MPPARSE || X86_VOYAGER
270 bool "Enable MPS table"
271 depends on X86_LOCAL_APIC
273 For old smp systems that do not have proper acpi support. Newer systems
274 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
280 depends on X86_LOCAL_APIC
284 prompt "Subarchitecture Type"
290 Choose this option if your computer is a standard PC or compatible.
296 Select this for an AMD Elan processor.
298 Do not use this option for K6/Athlon/Opteron processors!
300 If unsure, choose "PC-compatible" instead.
304 depends on X86_32 && (SMP || BROKEN) && !PCI
306 Voyager is an MCA-based 32-way capable SMP architecture proprietary
307 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
311 If you do not specifically know you have a Voyager based machine,
312 say N here, otherwise the kernel you build will not be bootable.
314 config X86_GENERICARCH
315 bool "Generic architecture"
318 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
319 subarchitectures. It is intended for a generic binary kernel.
320 if you select them all, kernel will probe it one by one. and will
326 bool "NUMAQ (IBM/Sequent)"
327 depends on SMP && X86_32 && PCI && X86_MPPARSE
330 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
331 NUMA multiquad box. This changes the way that processors are
332 bootstrapped, and uses Clustered Logical APIC addressing mode instead
333 of Flat Logical. You will need a new lynxer.elf file to flash your
334 firmware with - send email to <Martin.Bligh@us.ibm.com>.
337 bool "Summit/EXA (IBM x440)"
338 depends on X86_32 && SMP
340 This option is needed for IBM systems that use the Summit/EXA chipset.
341 In particular, it is needed for the x440.
344 bool "Support for Unisys ES7000 IA32 series"
345 depends on X86_32 && SMP
347 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
348 supposed to run on an IA32-based Unisys ES7000 system.
351 bool "Support for big SMP systems with more than 8 CPUs"
352 depends on X86_32 && SMP
354 This option is needed for the systems that have more than 8 CPUs
355 and if the system is not of any sub-arch type above.
360 bool "Support for ScaleMP vSMP"
362 depends on X86_64 && PCI
364 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
365 supposed to run on these EM64T-based machines. Only choose this option
366 if you have one of these machines.
371 bool "SGI 320/540 (Visual Workstation)"
372 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
374 The SGI Visual Workstation series is an IA32-based workstation
375 based on SGI systems chips with some legacy PC hardware attached.
377 Say Y here to create a kernel to run on the SGI 320 or 540.
379 A kernel compiled for the Visual Workstation will run on general
380 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
383 bool "RDC R-321x SoC"
386 select X86_REBOOTFIXUPS
388 This option is needed for RDC R-321x system-on-chip, also known
390 If you don't have one of these chips, you should say N here.
392 config SCHED_NO_NO_OMIT_FRAME_POINTER
394 prompt "Single-depth WCHAN output"
397 Calculate simpler /proc/<PID>/wchan values. If this option
398 is disabled then wchan values will recurse back to the
399 caller function. This provides more accurate wchan values,
400 at the expense of slightly more scheduling overhead.
402 If in doubt, say "Y".
404 menuconfig PARAVIRT_GUEST
405 bool "Paravirtualized guest support"
407 Say Y here to get to see options related to running Linux under
408 various hypervisors. This option alone does not add any kernel code.
410 If you say N, all options in this submenu will be skipped and disabled.
414 source "arch/x86/xen/Kconfig"
417 bool "VMI Guest support"
420 depends on !X86_VOYAGER
422 VMI provides a paravirtualized interface to the VMware ESX server
423 (it could be used by other hypervisors in theory too, but is not
424 at the moment), by linking the kernel to a GPL-ed ROM module
425 provided by the hypervisor.
428 bool "KVM paravirtualized clock"
430 select PARAVIRT_CLOCK
431 depends on !X86_VOYAGER
433 Turning on this option will allow you to run a paravirtualized clock
434 when running over the KVM hypervisor. Instead of relying on a PIT
435 (or probably other) emulation by the underlying device model, the host
436 provides the guest with timing infrastructure such as time of day, and
440 bool "KVM Guest support"
442 depends on !X86_VOYAGER
444 This option enables various optimizations for running under the KVM
447 source "arch/x86/lguest/Kconfig"
450 bool "Enable paravirtualization code"
451 depends on !X86_VOYAGER
453 This changes the kernel so it can modify itself when it is run
454 under a hypervisor, potentially improving performance significantly
455 over full virtualization. However, when run without a hypervisor
456 the kernel is theoretically slower and slightly larger.
458 config PARAVIRT_CLOCK
464 config PARAVIRT_DEBUG
465 bool "paravirt-ops debugging"
466 depends on PARAVIRT && DEBUG_KERNEL
468 Enable to debug paravirt_ops internals. Specifically, BUG if
469 a paravirt_op is missing when it is called.
474 This option adds a kernel parameter 'memtest', which allows memtest
476 memtest=0, mean disabled; -- default
477 memtest=1, mean do 1 test pattern;
479 memtest=4, mean do 4 test patterns.
480 If you are unsure how to answer this question, answer N.
482 config X86_SUMMIT_NUMA
484 depends on X86_32 && NUMA && X86_GENERICARCH
486 config X86_CYCLONE_TIMER
488 depends on X86_GENERICARCH
490 config ES7000_CLUSTERED_APIC
492 depends on SMP && X86_ES7000 && MPENTIUMIII
494 source "arch/x86/Kconfig.cpu"
498 prompt "HPET Timer Support" if X86_32
500 Use the IA-PC HPET (High Precision Event Timer) to manage
501 time in preference to the PIT and RTC, if a HPET is
503 HPET is the next generation timer replacing legacy 8254s.
504 The HPET provides a stable time base on SMP
505 systems, unlike the TSC, but it is more expensive to access,
506 as it is off-chip. You can find the HPET spec at
507 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
509 You can safely choose Y here. However, HPET will only be
510 activated if the platform and the BIOS support this feature.
511 Otherwise the 8254 will be used for timing services.
513 Choose N to continue using the legacy 8254 timer.
515 config HPET_EMULATE_RTC
517 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
519 # Mark as embedded because too many people got it wrong.
520 # The code disables itself when not needed.
523 bool "Enable DMI scanning" if EMBEDDED
525 Enabled scanning of DMI to identify machine quirks. Say Y
526 here unless you have verified that your setup is not
527 affected by entries in the DMI blacklist. Required by PNP
531 bool "GART IOMMU support" if EMBEDDED
535 depends on X86_64 && PCI
537 Support for full DMA access of devices with 32bit memory access only
538 on systems with more than 3GB. This is usually needed for USB,
539 sound, many IDE/SATA chipsets and some other devices.
540 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
541 based hardware IOMMU and a software bounce buffer based IOMMU used
542 on Intel systems and as fallback.
543 The code is only active when needed (enough memory and limited
544 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
548 bool "IBM Calgary IOMMU support"
550 depends on X86_64 && PCI && EXPERIMENTAL
552 Support for hardware IOMMUs in IBM's xSeries x366 and x460
553 systems. Needed to run systems with more than 3GB of memory
554 properly with 32-bit PCI devices that do not support DAC
555 (Double Address Cycle). Calgary also supports bus level
556 isolation, where all DMAs pass through the IOMMU. This
557 prevents them from going anywhere except their intended
558 destination. This catches hard-to-find kernel bugs and
559 mis-behaving drivers and devices that do not use the DMA-API
560 properly to set up their DMA buffers. The IOMMU can be
561 turned off at boot time with the iommu=off parameter.
562 Normally the kernel will make the right choice by itself.
565 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
567 prompt "Should Calgary be enabled by default?"
568 depends on CALGARY_IOMMU
570 Should Calgary be enabled by default? if you choose 'y', Calgary
571 will be used (if it exists). If you choose 'n', Calgary will not be
572 used even if it exists. If you choose 'n' and would like to use
573 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
577 bool "AMD IOMMU support"
580 depends on X86_64 && PCI && ACPI
582 With this option you can enable support for AMD IOMMU hardware in
583 your system. An IOMMU is a hardware component which provides
584 remapping of DMA memory accesses from devices. With an AMD IOMMU you
585 can isolate the the DMA memory of different devices and protect the
586 system from misbehaving device drivers or hardware.
588 You can find out if your system has an AMD IOMMU if you look into
589 your BIOS for an option to enable it or if you have an IVRS ACPI
592 # need this always selected by IOMMU for the VIA workaround
596 Support for software bounce buffers used on x86-64 systems
597 which don't have a hardware IOMMU (e.g. the current generation
598 of Intel's x86-64 CPUs). Using this PCI devices which can only
599 access 32-bits of memory can be used on systems with more than
600 3 GB of memory. If unsure, say Y.
603 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
606 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
607 depends on X86_64 && SMP && BROKEN
610 Configure maximum number of CPUS and NUMA Nodes for this architecture.
614 int "Maximum number of CPUs (2-512)" if !MAXSMP
617 default "4096" if MAXSMP
618 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
621 This allows you to specify the maximum number of CPUs which this
622 kernel will support. The maximum supported value is 512 and the
623 minimum value which makes sense is 2.
625 This is purely to save memory - each supported CPU adds
626 approximately eight kilobytes to the kernel image.
629 bool "SMT (Hyperthreading) scheduler support"
632 SMT scheduler support improves the CPU scheduler's decision making
633 when dealing with Intel Pentium 4 chips with HyperThreading at a
634 cost of slightly increased overhead in some places. If unsure say
639 prompt "Multi-core scheduler support"
642 Multi-core scheduler support improves the CPU scheduler's decision
643 making when dealing with multi-core CPU chips at a cost of slightly
644 increased overhead in some places. If unsure say N here.
646 source "kernel/Kconfig.preempt"
649 bool "Local APIC support on uniprocessors"
650 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
652 A local APIC (Advanced Programmable Interrupt Controller) is an
653 integrated interrupt controller in the CPU. If you have a single-CPU
654 system which has a processor with a local APIC, you can say Y here to
655 enable and use it. If you say Y here even though your machine doesn't
656 have a local APIC, then the kernel will still run with no slowdown at
657 all. The local APIC supports CPU-generated self-interrupts (timer,
658 performance counters), and the NMI watchdog which detects hard
662 bool "IO-APIC support on uniprocessors"
663 depends on X86_UP_APIC
665 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
666 SMP-capable replacement for PC-style interrupt controllers. Most
667 SMP systems and many recent uniprocessor systems have one.
669 If you have a single-CPU system with an IO-APIC, you can say Y here
670 to use it. If you say Y here even though your machine doesn't have
671 an IO-APIC, then the kernel will still run with no slowdown at all.
673 config X86_LOCAL_APIC
675 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
679 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
681 config X86_VISWS_APIC
683 depends on X86_32 && X86_VISWS
686 bool "Machine Check Exception"
687 depends on !X86_VOYAGER
689 Machine Check Exception support allows the processor to notify the
690 kernel if it detects a problem (e.g. overheating, component failure).
691 The action the kernel takes depends on the severity of the problem,
692 ranging from a warning message on the console, to halting the machine.
693 Your processor must be a Pentium or newer to support this - check the
694 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
695 have a design flaw which leads to false MCE events - hence MCE is
696 disabled on all P5 processors, unless explicitly enabled with "mce"
697 as a boot argument. Similarly, if MCE is built in and creates a
698 problem on some new non-standard machine, you can boot with "nomce"
699 to disable it. MCE support simply ignores non-MCE processors like
700 the 386 and 486, so nearly everyone can say Y here.
704 prompt "Intel MCE features"
705 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
707 Additional support for intel specific MCE features such as
712 prompt "AMD MCE features"
713 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
715 Additional support for AMD specific MCE features such as
716 the DRAM Error Threshold.
718 config X86_MCE_NONFATAL
719 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
720 depends on X86_32 && X86_MCE
722 Enabling this feature starts a timer that triggers every 5 seconds which
723 will look at the machine check registers to see if anything happened.
724 Non-fatal problems automatically get corrected (but still logged).
725 Disable this if you don't want to see these messages.
726 Seeing the messages this option prints out may be indicative of dying
727 or out-of-spec (ie, overclocked) hardware.
728 This option only does something on certain CPUs.
729 (AMD Athlon/Duron and Intel Pentium 4)
731 config X86_MCE_P4THERMAL
732 bool "check for P4 thermal throttling interrupt."
733 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
735 Enabling this feature will cause a message to be printed when the P4
736 enters thermal throttling.
739 bool "Enable VM86 support" if EMBEDDED
743 This option is required by programs like DOSEMU to run 16-bit legacy
744 code on X86 processors. It also may be needed by software like
745 XFree86 to initialize some video cards via BIOS. Disabling this
746 option saves about 6k.
749 tristate "Toshiba Laptop support"
752 This adds a driver to safely access the System Management Mode of
753 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
754 not work on models with a Phoenix BIOS. The System Management Mode
755 is used to set the BIOS and power saving options on Toshiba portables.
757 For information on utilities to make use of this driver see the
758 Toshiba Linux utilities web site at:
759 <http://www.buzzard.org.uk/toshiba/>.
761 Say Y if you intend to run this kernel on a Toshiba portable.
765 tristate "Dell laptop support"
767 This adds a driver to safely access the System Management Mode
768 of the CPU on the Dell Inspiron 8000. The System Management Mode
769 is used to read cpu temperature and cooling fan status and to
770 control the fans on the I8K portables.
772 This driver has been tested only on the Inspiron 8000 but it may
773 also work with other Dell laptops. You can force loading on other
774 models by passing the parameter `force=1' to the module. Use at
777 For information on utilities to make use of this driver see the
778 I8K Linux utilities web site at:
779 <http://people.debian.org/~dz/i8k/>
781 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
784 config X86_REBOOTFIXUPS
785 bool "Enable X86 board specific fixups for reboot"
788 This enables chipset and/or board specific fixups to be done
789 in order to get reboot to work correctly. This is only needed on
790 some combinations of hardware and BIOS. The symptom, for which
791 this config is intended, is when reboot ends with a stalled/hung
794 Currently, the only fixup is for the Geode machines using
795 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
797 Say Y if you want to enable the fixup. Currently, it's safe to
798 enable this option even if you don't need it.
802 tristate "/dev/cpu/microcode - microcode support"
805 If you say Y here, you will be able to update the microcode on
806 certain Intel and AMD processors. The Intel support is for the
807 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
808 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
809 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
810 You will obviously need the actual microcode binary data itself
811 which is not shipped with the Linux kernel.
813 This option selects the general module only, you need to select
814 at least one vendor specific module as well.
816 To compile this driver as a module, choose M here: the
817 module will be called microcode.
819 config MICROCODE_INTEL
820 bool "Intel microcode patch loading support"
825 This options enables microcode patch loading support for Intel
828 For latest news and information on obtaining all the required
829 Intel ingredients for this driver, check:
830 <http://www.urbanmyth.org/microcode/>.
833 bool "AMD microcode patch loading support"
837 If you select this option, microcode patch loading support for AMD
838 processors will be enabled.
840 config MICROCODE_OLD_INTERFACE
845 tristate "/dev/cpu/*/msr - Model-specific register support"
847 This device gives privileged processes access to the x86
848 Model-Specific Registers (MSRs). It is a character device with
849 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
850 MSR accesses are directed to a specific CPU on multi-processor
854 tristate "/dev/cpu/*/cpuid - CPU information support"
856 This device gives processes access to the x86 CPUID instruction to
857 be executed on a specific processor. It is a character device
858 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
862 prompt "High Memory Support"
863 default HIGHMEM4G if !X86_NUMAQ
864 default HIGHMEM64G if X86_NUMAQ
869 depends on !X86_NUMAQ
871 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
872 However, the address space of 32-bit x86 processors is only 4
873 Gigabytes large. That means that, if you have a large amount of
874 physical memory, not all of it can be "permanently mapped" by the
875 kernel. The physical memory that's not permanently mapped is called
878 If you are compiling a kernel which will never run on a machine with
879 more than 1 Gigabyte total physical RAM, answer "off" here (default
880 choice and suitable for most users). This will result in a "3GB/1GB"
881 split: 3GB are mapped so that each process sees a 3GB virtual memory
882 space and the remaining part of the 4GB virtual memory space is used
883 by the kernel to permanently map as much physical memory as
886 If the machine has between 1 and 4 Gigabytes physical RAM, then
889 If more than 4 Gigabytes is used then answer "64GB" here. This
890 selection turns Intel PAE (Physical Address Extension) mode on.
891 PAE implements 3-level paging on IA32 processors. PAE is fully
892 supported by Linux, PAE mode is implemented on all recent Intel
893 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
894 then the kernel will not boot on CPUs that don't support PAE!
896 The actual amount of total physical memory will either be
897 auto detected or can be forced by using a kernel command line option
898 such as "mem=256M". (Try "man bootparam" or see the documentation of
899 your boot loader (lilo or loadlin) about how to pass options to the
900 kernel at boot time.)
902 If unsure, say "off".
906 depends on !X86_NUMAQ
908 Select this if you have a 32-bit processor and between 1 and 4
909 gigabytes of physical RAM.
913 depends on !M386 && !M486
916 Select this if you have a 32-bit processor and more than 4
917 gigabytes of physical RAM.
922 depends on EXPERIMENTAL
923 prompt "Memory split" if EMBEDDED
927 Select the desired split between kernel and user memory.
929 If the address range available to the kernel is less than the
930 physical memory installed, the remaining memory will be available
931 as "high memory". Accessing high memory is a little more costly
932 than low memory, as it needs to be mapped into the kernel first.
933 Note that increasing the kernel address space limits the range
934 available to user programs, making the address space there
935 tighter. Selecting anything other than the default 3G/1G split
936 will also likely make your kernel incompatible with binary-only
939 If you are not absolutely sure what you are doing, leave this
943 bool "3G/1G user/kernel split"
944 config VMSPLIT_3G_OPT
946 bool "3G/1G user/kernel split (for full 1G low memory)"
948 bool "2G/2G user/kernel split"
949 config VMSPLIT_2G_OPT
951 bool "2G/2G user/kernel split (for full 2G low memory)"
953 bool "1G/3G user/kernel split"
958 default 0xB0000000 if VMSPLIT_3G_OPT
959 default 0x80000000 if VMSPLIT_2G
960 default 0x78000000 if VMSPLIT_2G_OPT
961 default 0x40000000 if VMSPLIT_1G
967 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
970 bool "PAE (Physical Address Extension) Support"
971 depends on X86_32 && !HIGHMEM4G
973 PAE is required for NX support, and furthermore enables
974 larger swapspace support for non-overcommit purposes. It
975 has the cost of more pagetable lookup overhead, and also
976 consumes more pagetable space per process.
978 config ARCH_PHYS_ADDR_T_64BIT
979 def_bool X86_64 || X86_PAE
981 # Common NUMA Features
983 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
985 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
987 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
989 Enable NUMA (Non Uniform Memory Access) support.
990 The kernel will try to allocate memory used by a CPU on the
991 local memory controller of the CPU and add some more
992 NUMA awareness to the kernel.
994 For 32-bit this is currently highly experimental and should be only
995 used for kernel development. It might also cause boot failures.
996 For 64-bit this is recommended on all multiprocessor Opteron systems.
997 If the system is EM64T, you should say N unless your system is
1000 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1001 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1005 prompt "Old style AMD Opteron NUMA detection"
1006 depends on X86_64 && NUMA && PCI
1008 Enable K8 NUMA node topology detection. You should say Y here if
1009 you have a multi processor AMD K8 system. This uses an old
1010 method to read the NUMA configuration directly from the builtin
1011 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1012 instead, which also takes priority if both are compiled in.
1014 config X86_64_ACPI_NUMA
1016 prompt "ACPI NUMA detection"
1017 depends on X86_64 && NUMA && ACPI && PCI
1020 Enable ACPI SRAT based node topology detection.
1022 # Some NUMA nodes have memory ranges that span
1023 # other nodes. Even though a pfn is valid and
1024 # between a node's start and end pfns, it may not
1025 # reside on that node. See memmap_init_zone()
1027 config NODES_SPAN_OTHER_NODES
1029 depends on X86_64_ACPI_NUMA
1032 bool "NUMA emulation"
1033 depends on X86_64 && NUMA
1035 Enable NUMA emulation. A flat machine will be split
1036 into virtual nodes when booted with "numa=fake=N", where N is the
1037 number of nodes. This is only useful for debugging.
1040 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1042 default "9" if MAXSMP
1043 default "6" if X86_64
1044 default "4" if X86_NUMAQ
1046 depends on NEED_MULTIPLE_NODES
1048 Specify the maximum number of NUMA Nodes available on the target
1049 system. Increases memory reserved to accomodate various tables.
1051 config HAVE_ARCH_BOOTMEM_NODE
1053 depends on X86_32 && NUMA
1055 config ARCH_HAVE_MEMORY_PRESENT
1057 depends on X86_32 && DISCONTIGMEM
1059 config NEED_NODE_MEMMAP_SIZE
1061 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1063 config HAVE_ARCH_ALLOC_REMAP
1065 depends on X86_32 && NUMA
1067 config ARCH_FLATMEM_ENABLE
1069 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1071 config ARCH_DISCONTIGMEM_ENABLE
1073 depends on NUMA && X86_32
1075 config ARCH_DISCONTIGMEM_DEFAULT
1077 depends on NUMA && X86_32
1079 config ARCH_SPARSEMEM_DEFAULT
1083 config ARCH_SPARSEMEM_ENABLE
1085 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1086 select SPARSEMEM_STATIC if X86_32
1087 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1089 config ARCH_SELECT_MEMORY_MODEL
1091 depends on ARCH_SPARSEMEM_ENABLE
1093 config ARCH_MEMORY_PROBE
1095 depends on MEMORY_HOTPLUG
1100 bool "Allocate 3rd-level pagetables from highmem"
1101 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1103 The VM uses one page table entry for each page of physical memory.
1104 For systems with a lot of RAM, this can be wasteful of precious
1105 low memory. Setting this option will put user-space page table
1106 entries in high memory.
1108 config X86_CHECK_BIOS_CORRUPTION
1109 bool "Check for low memory corruption"
1111 Periodically check for memory corruption in low memory, which
1112 is suspected to be caused by BIOS. Even when enabled in the
1113 configuration, it is disabled at runtime. Enable it by
1114 setting "memory_corruption_check=1" on the kernel command
1115 line. By default it scans the low 64k of memory every 60
1116 seconds; see the memory_corruption_check_size and
1117 memory_corruption_check_period parameters in
1118 Documentation/kernel-parameters.txt to adjust this.
1120 When enabled with the default parameters, this option has
1121 almost no overhead, as it reserves a relatively small amount
1122 of memory and scans it infrequently. It both detects corruption
1123 and prevents it from affecting the running system.
1125 It is, however, intended as a diagnostic tool; if repeatable
1126 BIOS-originated corruption always affects the same memory,
1127 you can use memmap= to prevent the kernel from using that
1130 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1131 bool "Set the default setting of memory_corruption_check"
1132 depends on X86_CHECK_BIOS_CORRUPTION
1135 Set whether the default state of memory_corruption_check is
1138 config X86_RESERVE_LOW_64K
1139 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1142 Reserve the first 64K of physical RAM on BIOSes that are known
1143 to potentially corrupt that memory range. A numbers of BIOSes are
1144 known to utilize this area during suspend/resume, so it must not
1145 be used by the kernel.
1147 Set this to N if you are absolutely sure that you trust the BIOS
1148 to get all its memory reservations and usages right.
1150 If you have doubts about the BIOS (e.g. suspend/resume does not
1151 work or there's kernel crashes after certain hardware hotplug
1152 events) and it's not AMI or Phoenix, then you might want to enable
1153 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1154 corruption patterns.
1158 config MATH_EMULATION
1160 prompt "Math emulation" if X86_32
1162 Linux can emulate a math coprocessor (used for floating point
1163 operations) if you don't have one. 486DX and Pentium processors have
1164 a math coprocessor built in, 486SX and 386 do not, unless you added
1165 a 487DX or 387, respectively. (The messages during boot time can
1166 give you some hints here ["man dmesg"].) Everyone needs either a
1167 coprocessor or this emulation.
1169 If you don't have a math coprocessor, you need to say Y here; if you
1170 say Y here even though you have a coprocessor, the coprocessor will
1171 be used nevertheless. (This behavior can be changed with the kernel
1172 command line option "no387", which comes handy if your coprocessor
1173 is broken. Try "man bootparam" or see the documentation of your boot
1174 loader (lilo or loadlin) about how to pass options to the kernel at
1175 boot time.) This means that it is a good idea to say Y here if you
1176 intend to use this kernel on different machines.
1178 More information about the internals of the Linux math coprocessor
1179 emulation can be found in <file:arch/x86/math-emu/README>.
1181 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1182 kernel, it won't hurt.
1185 bool "MTRR (Memory Type Range Register) support"
1187 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1188 the Memory Type Range Registers (MTRRs) may be used to control
1189 processor access to memory ranges. This is most useful if you have
1190 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1191 allows bus write transfers to be combined into a larger transfer
1192 before bursting over the PCI/AGP bus. This can increase performance
1193 of image write operations 2.5 times or more. Saying Y here creates a
1194 /proc/mtrr file which may be used to manipulate your processor's
1195 MTRRs. Typically the X server should use this.
1197 This code has a reasonably generic interface so that similar
1198 control registers on other processors can be easily supported
1201 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1202 Registers (ARRs) which provide a similar functionality to MTRRs. For
1203 these, the ARRs are used to emulate the MTRRs.
1204 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1205 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1206 write-combining. All of these processors are supported by this code
1207 and it makes sense to say Y here if you have one of them.
1209 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1210 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1211 can lead to all sorts of problems, so it's good to say Y here.
1213 You can safely say Y even if your machine doesn't have MTRRs, you'll
1214 just add about 9 KB to your kernel.
1216 See <file:Documentation/x86/mtrr.txt> for more information.
1218 config MTRR_SANITIZER
1220 prompt "MTRR cleanup support"
1223 Convert MTRR layout from continuous to discrete, so X drivers can
1224 add writeback entries.
1226 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1227 The largest mtrr entry size for a continous block can be set with
1232 config MTRR_SANITIZER_ENABLE_DEFAULT
1233 int "MTRR cleanup enable value (0-1)"
1236 depends on MTRR_SANITIZER
1238 Enable mtrr cleanup default value
1240 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1241 int "MTRR cleanup spare reg num (0-7)"
1244 depends on MTRR_SANITIZER
1246 mtrr cleanup spare entries default, it can be changed via
1247 mtrr_spare_reg_nr=N on the kernel command line.
1251 prompt "x86 PAT support"
1254 Use PAT attributes to setup page level cache control.
1256 PATs are the modern equivalents of MTRRs and are much more
1257 flexible than MTRRs.
1259 Say N here if you see bootup problems (boot crash, boot hang,
1260 spontaneous reboots) or a non-working video driver.
1265 bool "EFI runtime service support"
1268 This enables the kernel to use EFI runtime services that are
1269 available (such as the EFI variable services).
1271 This option is only useful on systems that have EFI firmware.
1272 In addition, you should use the latest ELILO loader available
1273 at <http://elilo.sourceforge.net> in order to take advantage
1274 of EFI runtime services. However, even with this option, the
1275 resultant kernel should continue to boot on existing non-EFI
1280 prompt "Enable seccomp to safely compute untrusted bytecode"
1282 This kernel feature is useful for number crunching applications
1283 that may need to compute untrusted bytecode during their
1284 execution. By using pipes or other transports made available to
1285 the process as file descriptors supporting the read/write
1286 syscalls, it's possible to isolate those applications in
1287 their own address space using seccomp. Once seccomp is
1288 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1289 and the task is only allowed to execute a few safe syscalls
1290 defined by each seccomp mode.
1292 If unsure, say Y. Only embedded should say N here.
1294 config CC_STACKPROTECTOR
1295 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1296 depends on X86_64 && EXPERIMENTAL && BROKEN
1298 This option turns on the -fstack-protector GCC feature. This
1299 feature puts, at the beginning of critical functions, a canary
1300 value on the stack just before the return address, and validates
1301 the value just before actually returning. Stack based buffer
1302 overflows (that need to overwrite this return address) now also
1303 overwrite the canary, which gets detected and the attack is then
1304 neutralized via a kernel panic.
1306 This feature requires gcc version 4.2 or above, or a distribution
1307 gcc with the feature backported. Older versions are automatically
1308 detected and for those versions, this configuration option is ignored.
1310 config CC_STACKPROTECTOR_ALL
1311 bool "Use stack-protector for all functions"
1312 depends on CC_STACKPROTECTOR
1314 Normally, GCC only inserts the canary value protection for
1315 functions that use large-ish on-stack buffers. By enabling
1316 this option, GCC will be asked to do this for ALL functions.
1318 source kernel/Kconfig.hz
1321 bool "kexec system call"
1322 depends on X86_BIOS_REBOOT
1324 kexec is a system call that implements the ability to shutdown your
1325 current kernel, and to start another kernel. It is like a reboot
1326 but it is independent of the system firmware. And like a reboot
1327 you can start any kernel with it, not just Linux.
1329 The name comes from the similarity to the exec system call.
1331 It is an ongoing process to be certain the hardware in a machine
1332 is properly shutdown, so do not be surprised if this code does not
1333 initially work for you. It may help to enable device hotplugging
1334 support. As of this writing the exact hardware interface is
1335 strongly in flux, so no good recommendation can be made.
1338 bool "kernel crash dumps"
1339 depends on X86_64 || (X86_32 && HIGHMEM)
1341 Generate crash dump after being started by kexec.
1342 This should be normally only set in special crash dump kernels
1343 which are loaded in the main kernel with kexec-tools into
1344 a specially reserved region and then later executed after
1345 a crash by kdump/kexec. The crash dump kernel must be compiled
1346 to a memory address not used by the main kernel or BIOS using
1347 PHYSICAL_START, or it must be built as a relocatable image
1348 (CONFIG_RELOCATABLE=y).
1349 For more details see Documentation/kdump/kdump.txt
1352 bool "kexec jump (EXPERIMENTAL)"
1353 depends on EXPERIMENTAL
1354 depends on KEXEC && HIBERNATION && X86_32
1356 Jump between original kernel and kexeced kernel and invoke
1357 code in physical address mode via KEXEC
1359 config PHYSICAL_START
1360 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1361 default "0x1000000" if X86_NUMAQ
1362 default "0x200000" if X86_64
1365 This gives the physical address where the kernel is loaded.
1367 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1368 bzImage will decompress itself to above physical address and
1369 run from there. Otherwise, bzImage will run from the address where
1370 it has been loaded by the boot loader and will ignore above physical
1373 In normal kdump cases one does not have to set/change this option
1374 as now bzImage can be compiled as a completely relocatable image
1375 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1376 address. This option is mainly useful for the folks who don't want
1377 to use a bzImage for capturing the crash dump and want to use a
1378 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1379 to be specifically compiled to run from a specific memory area
1380 (normally a reserved region) and this option comes handy.
1382 So if you are using bzImage for capturing the crash dump, leave
1383 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1384 Otherwise if you plan to use vmlinux for capturing the crash dump
1385 change this value to start of the reserved region (Typically 16MB
1386 0x1000000). In other words, it can be set based on the "X" value as
1387 specified in the "crashkernel=YM@XM" command line boot parameter
1388 passed to the panic-ed kernel. Typically this parameter is set as
1389 crashkernel=64M@16M. Please take a look at
1390 Documentation/kdump/kdump.txt for more details about crash dumps.
1392 Usage of bzImage for capturing the crash dump is recommended as
1393 one does not have to build two kernels. Same kernel can be used
1394 as production kernel and capture kernel. Above option should have
1395 gone away after relocatable bzImage support is introduced. But it
1396 is present because there are users out there who continue to use
1397 vmlinux for dump capture. This option should go away down the
1400 Don't change this unless you know what you are doing.
1403 bool "Build a relocatable kernel (EXPERIMENTAL)"
1404 depends on EXPERIMENTAL
1406 This builds a kernel image that retains relocation information
1407 so it can be loaded someplace besides the default 1MB.
1408 The relocations tend to make the kernel binary about 10% larger,
1409 but are discarded at runtime.
1411 One use is for the kexec on panic case where the recovery kernel
1412 must live at a different physical address than the primary
1415 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1416 it has been loaded at and the compile time physical address
1417 (CONFIG_PHYSICAL_START) is ignored.
1419 config PHYSICAL_ALIGN
1421 prompt "Alignment value to which kernel should be aligned" if X86_32
1422 default "0x100000" if X86_32
1423 default "0x200000" if X86_64
1424 range 0x2000 0x400000
1426 This value puts the alignment restrictions on physical address
1427 where kernel is loaded and run from. Kernel is compiled for an
1428 address which meets above alignment restriction.
1430 If bootloader loads the kernel at a non-aligned address and
1431 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1432 address aligned to above value and run from there.
1434 If bootloader loads the kernel at a non-aligned address and
1435 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1436 load address and decompress itself to the address it has been
1437 compiled for and run from there. The address for which kernel is
1438 compiled already meets above alignment restrictions. Hence the
1439 end result is that kernel runs from a physical address meeting
1440 above alignment restrictions.
1442 Don't change this unless you know what you are doing.
1445 bool "Support for hot-pluggable CPUs"
1446 depends on SMP && HOTPLUG && !X86_VOYAGER
1448 Say Y here to allow turning CPUs off and on. CPUs can be
1449 controlled through /sys/devices/system/cpu.
1450 ( Note: power management support will enable this option
1451 automatically on SMP systems. )
1452 Say N if you want to disable CPU hotplug.
1456 prompt "Compat VDSO support"
1457 depends on X86_32 || IA32_EMULATION
1459 Map the 32-bit VDSO to the predictable old-style address too.
1461 Say N here if you are running a sufficiently recent glibc
1462 version (2.3.3 or later), to remove the high-mapped
1463 VDSO mapping and to exclusively use the randomized VDSO.
1468 bool "Built-in kernel command line"
1471 Allow for specifying boot arguments to the kernel at
1472 build time. On some systems (e.g. embedded ones), it is
1473 necessary or convenient to provide some or all of the
1474 kernel boot arguments with the kernel itself (that is,
1475 to not rely on the boot loader to provide them.)
1477 To compile command line arguments into the kernel,
1478 set this option to 'Y', then fill in the
1479 the boot arguments in CONFIG_CMDLINE.
1481 Systems with fully functional boot loaders (i.e. non-embedded)
1482 should leave this option set to 'N'.
1485 string "Built-in kernel command string"
1486 depends on CMDLINE_BOOL
1489 Enter arguments here that should be compiled into the kernel
1490 image and used at boot time. If the boot loader provides a
1491 command line at boot time, it is appended to this string to
1492 form the full kernel command line, when the system boots.
1494 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1495 change this behavior.
1497 In most cases, the command line (whether built-in or provided
1498 by the boot loader) should specify the device for the root
1501 config CMDLINE_OVERRIDE
1502 bool "Built-in command line overrides boot loader arguments"
1504 depends on CMDLINE_BOOL
1506 Set this option to 'Y' to have the kernel ignore the boot loader
1507 command line, and use ONLY the built-in command line.
1509 This is used to work around broken boot loaders. This should
1510 be set to 'N' under normal conditions.
1514 config ARCH_ENABLE_MEMORY_HOTPLUG
1516 depends on X86_64 || (X86_32 && HIGHMEM)
1518 config HAVE_ARCH_EARLY_PFN_TO_NID
1522 menu "Power management and ACPI options"
1523 depends on !X86_VOYAGER
1525 config ARCH_HIBERNATION_HEADER
1527 depends on X86_64 && HIBERNATION
1529 source "kernel/power/Kconfig"
1531 source "drivers/acpi/Kconfig"
1536 depends on APM || APM_MODULE
1539 tristate "APM (Advanced Power Management) BIOS support"
1540 depends on X86_32 && PM_SLEEP
1542 APM is a BIOS specification for saving power using several different
1543 techniques. This is mostly useful for battery powered laptops with
1544 APM compliant BIOSes. If you say Y here, the system time will be
1545 reset after a RESUME operation, the /proc/apm device will provide
1546 battery status information, and user-space programs will receive
1547 notification of APM "events" (e.g. battery status change).
1549 If you select "Y" here, you can disable actual use of the APM
1550 BIOS by passing the "apm=off" option to the kernel at boot time.
1552 Note that the APM support is almost completely disabled for
1553 machines with more than one CPU.
1555 In order to use APM, you will need supporting software. For location
1556 and more information, read <file:Documentation/power/pm.txt> and the
1557 Battery Powered Linux mini-HOWTO, available from
1558 <http://www.tldp.org/docs.html#howto>.
1560 This driver does not spin down disk drives (see the hdparm(8)
1561 manpage ("man 8 hdparm") for that), and it doesn't turn off
1562 VESA-compliant "green" monitors.
1564 This driver does not support the TI 4000M TravelMate and the ACER
1565 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1566 desktop machines also don't have compliant BIOSes, and this driver
1567 may cause those machines to panic during the boot phase.
1569 Generally, if you don't have a battery in your machine, there isn't
1570 much point in using this driver and you should say N. If you get
1571 random kernel OOPSes or reboots that don't seem to be related to
1572 anything, try disabling/enabling this option (or disabling/enabling
1575 Some other things you should try when experiencing seemingly random,
1578 1) make sure that you have enough swap space and that it is
1580 2) pass the "no-hlt" option to the kernel
1581 3) switch on floating point emulation in the kernel and pass
1582 the "no387" option to the kernel
1583 4) pass the "floppy=nodma" option to the kernel
1584 5) pass the "mem=4M" option to the kernel (thereby disabling
1585 all but the first 4 MB of RAM)
1586 6) make sure that the CPU is not over clocked.
1587 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1588 8) disable the cache from your BIOS settings
1589 9) install a fan for the video card or exchange video RAM
1590 10) install a better fan for the CPU
1591 11) exchange RAM chips
1592 12) exchange the motherboard.
1594 To compile this driver as a module, choose M here: the
1595 module will be called apm.
1599 config APM_IGNORE_USER_SUSPEND
1600 bool "Ignore USER SUSPEND"
1602 This option will ignore USER SUSPEND requests. On machines with a
1603 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1604 series notebooks, it is necessary to say Y because of a BIOS bug.
1606 config APM_DO_ENABLE
1607 bool "Enable PM at boot time"
1609 Enable APM features at boot time. From page 36 of the APM BIOS
1610 specification: "When disabled, the APM BIOS does not automatically
1611 power manage devices, enter the Standby State, enter the Suspend
1612 State, or take power saving steps in response to CPU Idle calls."
1613 This driver will make CPU Idle calls when Linux is idle (unless this
1614 feature is turned off -- see "Do CPU IDLE calls", below). This
1615 should always save battery power, but more complicated APM features
1616 will be dependent on your BIOS implementation. You may need to turn
1617 this option off if your computer hangs at boot time when using APM
1618 support, or if it beeps continuously instead of suspending. Turn
1619 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1620 T400CDT. This is off by default since most machines do fine without
1624 bool "Make CPU Idle calls when idle"
1626 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1627 On some machines, this can activate improved power savings, such as
1628 a slowed CPU clock rate, when the machine is idle. These idle calls
1629 are made after the idle loop has run for some length of time (e.g.,
1630 333 mS). On some machines, this will cause a hang at boot time or
1631 whenever the CPU becomes idle. (On machines with more than one CPU,
1632 this option does nothing.)
1634 config APM_DISPLAY_BLANK
1635 bool "Enable console blanking using APM"
1637 Enable console blanking using the APM. Some laptops can use this to
1638 turn off the LCD backlight when the screen blanker of the Linux
1639 virtual console blanks the screen. Note that this is only used by
1640 the virtual console screen blanker, and won't turn off the backlight
1641 when using the X Window system. This also doesn't have anything to
1642 do with your VESA-compliant power-saving monitor. Further, this
1643 option doesn't work for all laptops -- it might not turn off your
1644 backlight at all, or it might print a lot of errors to the console,
1645 especially if you are using gpm.
1647 config APM_ALLOW_INTS
1648 bool "Allow interrupts during APM BIOS calls"
1650 Normally we disable external interrupts while we are making calls to
1651 the APM BIOS as a measure to lessen the effects of a badly behaving
1652 BIOS implementation. The BIOS should reenable interrupts if it
1653 needs to. Unfortunately, some BIOSes do not -- especially those in
1654 many of the newer IBM Thinkpads. If you experience hangs when you
1655 suspend, try setting this to Y. Otherwise, say N.
1657 config APM_REAL_MODE_POWER_OFF
1658 bool "Use real mode APM BIOS call to power off"
1660 Use real mode APM BIOS calls to switch off the computer. This is
1661 a work-around for a number of buggy BIOSes. Switch this option on if
1662 your computer crashes instead of powering off properly.
1666 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1668 source "drivers/cpuidle/Kconfig"
1670 source "drivers/idle/Kconfig"
1675 menu "Bus options (PCI etc.)"
1680 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1682 Find out whether you have a PCI motherboard. PCI is the name of a
1683 bus system, i.e. the way the CPU talks to the other stuff inside
1684 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1685 VESA. If you have PCI, say Y, otherwise N.
1688 prompt "PCI access mode"
1689 depends on X86_32 && PCI
1692 On PCI systems, the BIOS can be used to detect the PCI devices and
1693 determine their configuration. However, some old PCI motherboards
1694 have BIOS bugs and may crash if this is done. Also, some embedded
1695 PCI-based systems don't have any BIOS at all. Linux can also try to
1696 detect the PCI hardware directly without using the BIOS.
1698 With this option, you can specify how Linux should detect the
1699 PCI devices. If you choose "BIOS", the BIOS will be used,
1700 if you choose "Direct", the BIOS won't be used, and if you
1701 choose "MMConfig", then PCI Express MMCONFIG will be used.
1702 If you choose "Any", the kernel will try MMCONFIG, then the
1703 direct access method and falls back to the BIOS if that doesn't
1704 work. If unsure, go with the default, which is "Any".
1709 config PCI_GOMMCONFIG
1726 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1728 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1731 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1735 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1739 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1746 bool "Support mmconfig PCI config space access"
1747 depends on X86_64 && PCI && ACPI
1750 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1751 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1753 DMA remapping (DMAR) devices support enables independent address
1754 translations for Direct Memory Access (DMA) from devices.
1755 These DMA remapping devices are reported via ACPI tables
1756 and include PCI device scope covered by these DMA
1761 prompt "Support for Graphics workaround"
1764 Current Graphics drivers tend to use physical address
1765 for DMA and avoid using DMA APIs. Setting this config
1766 option permits the IOMMU driver to set a unity map for
1767 all the OS-visible memory. Hence the driver can continue
1768 to use physical addresses for DMA.
1770 config DMAR_FLOPPY_WA
1774 Floppy disk drivers are know to bypass DMA API calls
1775 thereby failing to work when IOMMU is enabled. This
1776 workaround will setup a 1:1 mapping for the first
1777 16M to make floppy (an ISA device) work.
1780 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1781 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1783 Supports Interrupt remapping for IO-APIC and MSI devices.
1784 To use x2apic mode in the CPU's which support x2APIC enhancements or
1785 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1787 source "drivers/pci/pcie/Kconfig"
1789 source "drivers/pci/Kconfig"
1791 # x86_64 have no ISA slots, but do have ISA-style DMA.
1799 depends on !X86_VOYAGER
1801 Find out whether you have ISA slots on your motherboard. ISA is the
1802 name of a bus system, i.e. the way the CPU talks to the other stuff
1803 inside your box. Other bus systems are PCI, EISA, MicroChannel
1804 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1805 newer boards don't support it. If you have ISA, say Y, otherwise N.
1811 The Extended Industry Standard Architecture (EISA) bus was
1812 developed as an open alternative to the IBM MicroChannel bus.
1814 The EISA bus provided some of the features of the IBM MicroChannel
1815 bus while maintaining backward compatibility with cards made for
1816 the older ISA bus. The EISA bus saw limited use between 1988 and
1817 1995 when it was made obsolete by the PCI bus.
1819 Say Y here if you are building a kernel for an EISA-based machine.
1823 source "drivers/eisa/Kconfig"
1826 bool "MCA support" if !X86_VOYAGER
1827 default y if X86_VOYAGER
1829 MicroChannel Architecture is found in some IBM PS/2 machines and
1830 laptops. It is a bus system similar to PCI or ISA. See
1831 <file:Documentation/mca.txt> (and especially the web page given
1832 there) before attempting to build an MCA bus kernel.
1834 source "drivers/mca/Kconfig"
1837 tristate "NatSemi SCx200 support"
1838 depends on !X86_VOYAGER
1840 This provides basic support for National Semiconductor's
1841 (now AMD's) Geode processors. The driver probes for the
1842 PCI-IDs of several on-chip devices, so its a good dependency
1843 for other scx200_* drivers.
1845 If compiled as a module, the driver is named scx200.
1847 config SCx200HR_TIMER
1848 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1849 depends on SCx200 && GENERIC_TIME
1852 This driver provides a clocksource built upon the on-chip
1853 27MHz high-resolution timer. Its also a workaround for
1854 NSC Geode SC-1100's buggy TSC, which loses time when the
1855 processor goes idle (as is done by the scheduler). The
1856 other workaround is idle=poll boot option.
1858 config GEODE_MFGPT_TIMER
1860 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1861 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1863 This driver provides a clock event source based on the MFGPT
1864 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1865 MFGPTs have a better resolution and max interval than the
1866 generic PIT, and are suitable for use as high-res timers.
1869 bool "One Laptop Per Child support"
1872 Add support for detecting the unique features of the OLPC
1879 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1881 source "drivers/pcmcia/Kconfig"
1883 source "drivers/pci/hotplug/Kconfig"
1888 menu "Executable file formats / Emulations"
1890 source "fs/Kconfig.binfmt"
1892 config IA32_EMULATION
1893 bool "IA32 Emulation"
1895 select COMPAT_BINFMT_ELF
1897 Include code to run 32-bit programs under a 64-bit kernel. You should
1898 likely turn this on, unless you're 100% sure that you don't have any
1899 32-bit programs left.
1902 tristate "IA32 a.out support"
1903 depends on IA32_EMULATION
1905 Support old a.out binaries in the 32bit emulation.
1909 depends on IA32_EMULATION
1911 config COMPAT_FOR_U64_ALIGNMENT
1915 config SYSVIPC_COMPAT
1917 depends on COMPAT && SYSVIPC
1922 config HAVE_ATOMIC_IOMAP
1926 source "net/Kconfig"
1928 source "drivers/Kconfig"
1930 source "drivers/firmware/Kconfig"
1934 source "arch/x86/Kconfig.debug"
1936 source "security/Kconfig"
1938 source "crypto/Kconfig"
1940 source "arch/x86/kvm/Kconfig"
1942 source "lib/Kconfig"