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_UNSTABLE_SCHED_CLOCK
24 select HAVE_IOREMAP_PROT
26 select ARCH_WANT_OPTIONAL_GPIOLIB
27 select HAVE_KRETPROBES
28 select HAVE_FTRACE_MCOUNT_RECORD
29 select HAVE_DYNAMIC_FTRACE
31 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
32 select HAVE_ARCH_KGDB if !X86_VOYAGER
33 select HAVE_ARCH_TRACEHOOK
34 select HAVE_GENERIC_DMA_COHERENT if X86_32
35 select HAVE_EFFICIENT_UNALIGNED_ACCESS
39 default "arch/x86/configs/i386_defconfig" if X86_32
40 default "arch/x86/configs/x86_64_defconfig" if X86_64
43 config GENERIC_LOCKBREAK
49 config GENERIC_CMOS_UPDATE
52 config CLOCKSOURCE_WATCHDOG
55 config GENERIC_CLOCKEVENTS
58 config GENERIC_CLOCKEVENTS_BROADCAST
60 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
62 config LOCKDEP_SUPPORT
65 config STACKTRACE_SUPPORT
68 config HAVE_LATENCYTOP_SUPPORT
71 config FAST_CMPXCHG_LOCAL
84 config GENERIC_ISA_DMA
94 config GENERIC_HWEIGHT
100 config ARCH_MAY_HAVE_PC_FDC
103 config RWSEM_GENERIC_SPINLOCK
106 config RWSEM_XCHGADD_ALGORITHM
109 config ARCH_HAS_ILOG2_U32
112 config ARCH_HAS_ILOG2_U64
115 config ARCH_HAS_CPU_IDLE_WAIT
118 config GENERIC_CALIBRATE_DELAY
121 config GENERIC_TIME_VSYSCALL
125 config ARCH_HAS_CPU_RELAX
128 config ARCH_HAS_CACHE_LINE_SIZE
131 config HAVE_SETUP_PER_CPU_AREA
132 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
134 config HAVE_CPUMASK_OF_CPU_MAP
137 config ARCH_HIBERNATION_POSSIBLE
139 depends on !SMP || !X86_VOYAGER
141 config ARCH_SUSPEND_POSSIBLE
143 depends on !X86_VOYAGER
149 config ARCH_POPULATES_NODE_MAP
156 config ARCH_SUPPORTS_AOUT
159 config ARCH_SUPPORTS_OPTIMIZED_INLINING
162 # Use the generic interrupt handling code in kernel/irq/:
163 config GENERIC_HARDIRQS
167 config GENERIC_IRQ_PROBE
171 config GENERIC_PENDING_IRQ
173 depends on GENERIC_HARDIRQS && SMP
178 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
179 select USE_GENERIC_SMP_HELPERS
184 depends on X86_32 && SMP
188 depends on X86_64 && SMP
193 depends on (X86_32 && !X86_VOYAGER) || X86_64
196 config X86_BIOS_REBOOT
198 depends on !X86_VOYAGER
201 config X86_TRAMPOLINE
203 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
208 source "init/Kconfig"
210 menu "Processor type and features"
212 source "kernel/time/Kconfig"
215 bool "Symmetric multi-processing support"
217 This enables support for systems with more than one CPU. If you have
218 a system with only one CPU, like most personal computers, say N. If
219 you have a system with more than one CPU, say Y.
221 If you say N here, the kernel will run on single and multiprocessor
222 machines, but will use only one CPU of a multiprocessor machine. If
223 you say Y here, the kernel will run on many, but not all,
224 singleprocessor machines. On a singleprocessor machine, the kernel
225 will run faster if you say N here.
227 Note that if you say Y here and choose architecture "586" or
228 "Pentium" under "Processor family", the kernel will not work on 486
229 architectures. Similarly, multiprocessor kernels for the "PPro"
230 architecture may not work on all Pentium based boards.
232 People using multiprocessor machines who say Y here should also say
233 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
234 Management" code will be disabled if you say Y here.
236 See also <file:Documentation/i386/IO-APIC.txt>,
237 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
238 <http://www.tldp.org/docs.html#howto>.
240 If you don't know what to do here, say N.
242 config X86_FIND_SMP_CONFIG
244 depends on X86_MPPARSE || X86_VOYAGER
249 bool "Enable MPS table"
250 depends on X86_LOCAL_APIC
252 For old smp systems that do not have proper acpi support. Newer systems
253 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
259 depends on X86_LOCAL_APIC
263 prompt "Subarchitecture Type"
269 Choose this option if your computer is a standard PC or compatible.
275 Select this for an AMD Elan processor.
277 Do not use this option for K6/Athlon/Opteron processors!
279 If unsure, choose "PC-compatible" instead.
283 depends on X86_32 && (SMP || BROKEN) && !PCI
285 Voyager is an MCA-based 32-way capable SMP architecture proprietary
286 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
290 If you do not specifically know you have a Voyager based machine,
291 say N here, otherwise the kernel you build will not be bootable.
293 config X86_GENERICARCH
294 bool "Generic architecture"
297 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
298 subarchitectures. It is intended for a generic binary kernel.
299 if you select them all, kernel will probe it one by one. and will
305 bool "NUMAQ (IBM/Sequent)"
306 depends on SMP && X86_32 && PCI && X86_MPPARSE
309 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
310 NUMA multiquad box. This changes the way that processors are
311 bootstrapped, and uses Clustered Logical APIC addressing mode instead
312 of Flat Logical. You will need a new lynxer.elf file to flash your
313 firmware with - send email to <Martin.Bligh@us.ibm.com>.
316 bool "Summit/EXA (IBM x440)"
317 depends on X86_32 && SMP
319 This option is needed for IBM systems that use the Summit/EXA chipset.
320 In particular, it is needed for the x440.
323 bool "Support for Unisys ES7000 IA32 series"
324 depends on X86_32 && SMP
326 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
327 supposed to run on an IA32-based Unisys ES7000 system.
330 bool "Support for big SMP systems with more than 8 CPUs"
331 depends on X86_32 && SMP
333 This option is needed for the systems that have more than 8 CPUs
334 and if the system is not of any sub-arch type above.
339 bool "Support for ScaleMP vSMP"
341 depends on X86_64 && PCI
343 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
344 supposed to run on these EM64T-based machines. Only choose this option
345 if you have one of these machines.
350 bool "SGI 320/540 (Visual Workstation)"
351 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
353 The SGI Visual Workstation series is an IA32-based workstation
354 based on SGI systems chips with some legacy PC hardware attached.
356 Say Y here to create a kernel to run on the SGI 320 or 540.
358 A kernel compiled for the Visual Workstation will run on general
359 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
362 bool "RDC R-321x SoC"
365 select X86_REBOOTFIXUPS
367 This option is needed for RDC R-321x system-on-chip, also known
369 If you don't have one of these chips, you should say N here.
371 config SCHED_NO_NO_OMIT_FRAME_POINTER
373 prompt "Single-depth WCHAN output"
376 Calculate simpler /proc/<PID>/wchan values. If this option
377 is disabled then wchan values will recurse back to the
378 caller function. This provides more accurate wchan values,
379 at the expense of slightly more scheduling overhead.
381 If in doubt, say "Y".
383 menuconfig PARAVIRT_GUEST
384 bool "Paravirtualized guest support"
386 Say Y here to get to see options related to running Linux under
387 various hypervisors. This option alone does not add any kernel code.
389 If you say N, all options in this submenu will be skipped and disabled.
393 source "arch/x86/xen/Kconfig"
396 bool "VMI Guest support"
399 depends on !X86_VOYAGER
401 VMI provides a paravirtualized interface to the VMware ESX server
402 (it could be used by other hypervisors in theory too, but is not
403 at the moment), by linking the kernel to a GPL-ed ROM module
404 provided by the hypervisor.
407 bool "KVM paravirtualized clock"
409 select PARAVIRT_CLOCK
410 depends on !X86_VOYAGER
412 Turning on this option will allow you to run a paravirtualized clock
413 when running over the KVM hypervisor. Instead of relying on a PIT
414 (or probably other) emulation by the underlying device model, the host
415 provides the guest with timing infrastructure such as time of day, and
419 bool "KVM Guest support"
421 depends on !X86_VOYAGER
423 This option enables various optimizations for running under the KVM
426 source "arch/x86/lguest/Kconfig"
429 bool "Enable paravirtualization code"
430 depends on !X86_VOYAGER
432 This changes the kernel so it can modify itself when it is run
433 under a hypervisor, potentially improving performance significantly
434 over full virtualization. However, when run without a hypervisor
435 the kernel is theoretically slower and slightly larger.
437 config PARAVIRT_CLOCK
443 config PARAVIRT_DEBUG
444 bool "paravirt-ops debugging"
445 depends on PARAVIRT && DEBUG_KERNEL
447 Enable to debug paravirt_ops internals. Specifically, BUG if
448 a paravirt_op is missing when it is called.
453 This option adds a kernel parameter 'memtest', which allows memtest
455 memtest=0, mean disabled; -- default
456 memtest=1, mean do 1 test pattern;
458 memtest=4, mean do 4 test patterns.
459 If you are unsure how to answer this question, answer N.
461 config X86_SUMMIT_NUMA
463 depends on X86_32 && NUMA && X86_GENERICARCH
465 config X86_CYCLONE_TIMER
467 depends on X86_GENERICARCH
469 config ES7000_CLUSTERED_APIC
471 depends on SMP && X86_ES7000 && MPENTIUMIII
473 source "arch/x86/Kconfig.cpu"
477 prompt "HPET Timer Support" if X86_32
479 Use the IA-PC HPET (High Precision Event Timer) to manage
480 time in preference to the PIT and RTC, if a HPET is
482 HPET is the next generation timer replacing legacy 8254s.
483 The HPET provides a stable time base on SMP
484 systems, unlike the TSC, but it is more expensive to access,
485 as it is off-chip. You can find the HPET spec at
486 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
488 You can safely choose Y here. However, HPET will only be
489 activated if the platform and the BIOS support this feature.
490 Otherwise the 8254 will be used for timing services.
492 Choose N to continue using the legacy 8254 timer.
494 config HPET_EMULATE_RTC
496 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
498 # Mark as embedded because too many people got it wrong.
499 # The code disables itself when not needed.
502 bool "Enable DMI scanning" if EMBEDDED
504 Enabled scanning of DMI to identify machine quirks. Say Y
505 here unless you have verified that your setup is not
506 affected by entries in the DMI blacklist. Required by PNP
510 bool "GART IOMMU support" if EMBEDDED
514 depends on X86_64 && PCI
516 Support for full DMA access of devices with 32bit memory access only
517 on systems with more than 3GB. This is usually needed for USB,
518 sound, many IDE/SATA chipsets and some other devices.
519 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
520 based hardware IOMMU and a software bounce buffer based IOMMU used
521 on Intel systems and as fallback.
522 The code is only active when needed (enough memory and limited
523 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
527 bool "IBM Calgary IOMMU support"
529 depends on X86_64 && PCI && EXPERIMENTAL
531 Support for hardware IOMMUs in IBM's xSeries x366 and x460
532 systems. Needed to run systems with more than 3GB of memory
533 properly with 32-bit PCI devices that do not support DAC
534 (Double Address Cycle). Calgary also supports bus level
535 isolation, where all DMAs pass through the IOMMU. This
536 prevents them from going anywhere except their intended
537 destination. This catches hard-to-find kernel bugs and
538 mis-behaving drivers and devices that do not use the DMA-API
539 properly to set up their DMA buffers. The IOMMU can be
540 turned off at boot time with the iommu=off parameter.
541 Normally the kernel will make the right choice by itself.
544 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
546 prompt "Should Calgary be enabled by default?"
547 depends on CALGARY_IOMMU
549 Should Calgary be enabled by default? if you choose 'y', Calgary
550 will be used (if it exists). If you choose 'n', Calgary will not be
551 used even if it exists. If you choose 'n' and would like to use
552 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
556 bool "AMD IOMMU support"
559 depends on X86_64 && PCI && ACPI
561 With this option you can enable support for AMD IOMMU hardware in
562 your system. An IOMMU is a hardware component which provides
563 remapping of DMA memory accesses from devices. With an AMD IOMMU you
564 can isolate the the DMA memory of different devices and protect the
565 system from misbehaving device drivers or hardware.
567 You can find out if your system has an AMD IOMMU if you look into
568 your BIOS for an option to enable it or if you have an IVRS ACPI
571 # need this always selected by IOMMU for the VIA workaround
575 Support for software bounce buffers used on x86-64 systems
576 which don't have a hardware IOMMU (e.g. the current generation
577 of Intel's x86-64 CPUs). Using this PCI devices which can only
578 access 32-bits of memory can be used on systems with more than
579 3 GB of memory. If unsure, say Y.
582 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
585 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
586 depends on X86_64 && SMP && BROKEN
589 Configure maximum number of CPUS and NUMA Nodes for this architecture.
593 int "Maximum number of CPUs (2-512)" if !MAXSMP
596 default "4096" if MAXSMP
597 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
600 This allows you to specify the maximum number of CPUs which this
601 kernel will support. The maximum supported value is 512 and the
602 minimum value which makes sense is 2.
604 This is purely to save memory - each supported CPU adds
605 approximately eight kilobytes to the kernel image.
608 bool "SMT (Hyperthreading) scheduler support"
611 SMT scheduler support improves the CPU scheduler's decision making
612 when dealing with Intel Pentium 4 chips with HyperThreading at a
613 cost of slightly increased overhead in some places. If unsure say
618 prompt "Multi-core scheduler support"
621 Multi-core scheduler support improves the CPU scheduler's decision
622 making when dealing with multi-core CPU chips at a cost of slightly
623 increased overhead in some places. If unsure say N here.
625 source "kernel/Kconfig.preempt"
628 bool "Local APIC support on uniprocessors"
629 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
631 A local APIC (Advanced Programmable Interrupt Controller) is an
632 integrated interrupt controller in the CPU. If you have a single-CPU
633 system which has a processor with a local APIC, you can say Y here to
634 enable and use it. If you say Y here even though your machine doesn't
635 have a local APIC, then the kernel will still run with no slowdown at
636 all. The local APIC supports CPU-generated self-interrupts (timer,
637 performance counters), and the NMI watchdog which detects hard
641 bool "IO-APIC support on uniprocessors"
642 depends on X86_UP_APIC
644 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
645 SMP-capable replacement for PC-style interrupt controllers. Most
646 SMP systems and many recent uniprocessor systems have one.
648 If you have a single-CPU system with an IO-APIC, you can say Y here
649 to use it. If you say Y here even though your machine doesn't have
650 an IO-APIC, then the kernel will still run with no slowdown at all.
652 config X86_LOCAL_APIC
654 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
658 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
660 config X86_VISWS_APIC
662 depends on X86_32 && X86_VISWS
665 bool "Machine Check Exception"
666 depends on !X86_VOYAGER
668 Machine Check Exception support allows the processor to notify the
669 kernel if it detects a problem (e.g. overheating, component failure).
670 The action the kernel takes depends on the severity of the problem,
671 ranging from a warning message on the console, to halting the machine.
672 Your processor must be a Pentium or newer to support this - check the
673 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
674 have a design flaw which leads to false MCE events - hence MCE is
675 disabled on all P5 processors, unless explicitly enabled with "mce"
676 as a boot argument. Similarly, if MCE is built in and creates a
677 problem on some new non-standard machine, you can boot with "nomce"
678 to disable it. MCE support simply ignores non-MCE processors like
679 the 386 and 486, so nearly everyone can say Y here.
683 prompt "Intel MCE features"
684 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
686 Additional support for intel specific MCE features such as
691 prompt "AMD MCE features"
692 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
694 Additional support for AMD specific MCE features such as
695 the DRAM Error Threshold.
697 config X86_MCE_NONFATAL
698 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
699 depends on X86_32 && X86_MCE
701 Enabling this feature starts a timer that triggers every 5 seconds which
702 will look at the machine check registers to see if anything happened.
703 Non-fatal problems automatically get corrected (but still logged).
704 Disable this if you don't want to see these messages.
705 Seeing the messages this option prints out may be indicative of dying
706 or out-of-spec (ie, overclocked) hardware.
707 This option only does something on certain CPUs.
708 (AMD Athlon/Duron and Intel Pentium 4)
710 config X86_MCE_P4THERMAL
711 bool "check for P4 thermal throttling interrupt."
712 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
714 Enabling this feature will cause a message to be printed when the P4
715 enters thermal throttling.
718 bool "Enable VM86 support" if EMBEDDED
722 This option is required by programs like DOSEMU to run 16-bit legacy
723 code on X86 processors. It also may be needed by software like
724 XFree86 to initialize some video cards via BIOS. Disabling this
725 option saves about 6k.
728 tristate "Toshiba Laptop support"
731 This adds a driver to safely access the System Management Mode of
732 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
733 not work on models with a Phoenix BIOS. The System Management Mode
734 is used to set the BIOS and power saving options on Toshiba portables.
736 For information on utilities to make use of this driver see the
737 Toshiba Linux utilities web site at:
738 <http://www.buzzard.org.uk/toshiba/>.
740 Say Y if you intend to run this kernel on a Toshiba portable.
744 tristate "Dell laptop support"
746 This adds a driver to safely access the System Management Mode
747 of the CPU on the Dell Inspiron 8000. The System Management Mode
748 is used to read cpu temperature and cooling fan status and to
749 control the fans on the I8K portables.
751 This driver has been tested only on the Inspiron 8000 but it may
752 also work with other Dell laptops. You can force loading on other
753 models by passing the parameter `force=1' to the module. Use at
756 For information on utilities to make use of this driver see the
757 I8K Linux utilities web site at:
758 <http://people.debian.org/~dz/i8k/>
760 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
763 config X86_REBOOTFIXUPS
765 prompt "Enable X86 board specific fixups for reboot"
766 depends on X86_32 && X86
768 This enables chipset and/or board specific fixups to be done
769 in order to get reboot to work correctly. This is only needed on
770 some combinations of hardware and BIOS. The symptom, for which
771 this config is intended, is when reboot ends with a stalled/hung
774 Currently, the only fixup is for the Geode machines using
775 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
777 Say Y if you want to enable the fixup. Currently, it's safe to
778 enable this option even if you don't need it.
782 tristate "/dev/cpu/microcode - microcode support"
785 If you say Y here, you will be able to update the microcode on
786 certain Intel and AMD processors. The Intel support is for the
787 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
788 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
789 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
790 You will obviously need the actual microcode binary data itself
791 which is not shipped with the Linux kernel.
793 This option selects the general module only, you need to select
794 at least one vendor specific module as well.
796 To compile this driver as a module, choose M here: the
797 module will be called microcode.
799 config MICROCODE_INTEL
800 bool "Intel microcode patch loading support"
805 This options enables microcode patch loading support for Intel
808 For latest news and information on obtaining all the required
809 Intel ingredients for this driver, check:
810 <http://www.urbanmyth.org/microcode/>.
813 bool "AMD microcode patch loading support"
817 If you select this option, microcode patch loading support for AMD
818 processors will be enabled.
820 config MICROCODE_OLD_INTERFACE
825 tristate "/dev/cpu/*/msr - Model-specific register support"
827 This device gives privileged processes access to the x86
828 Model-Specific Registers (MSRs). It is a character device with
829 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
830 MSR accesses are directed to a specific CPU on multi-processor
834 tristate "/dev/cpu/*/cpuid - CPU information support"
836 This device gives processes access to the x86 CPUID instruction to
837 be executed on a specific processor. It is a character device
838 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
842 prompt "High Memory Support"
843 default HIGHMEM4G if !X86_NUMAQ
844 default HIGHMEM64G if X86_NUMAQ
849 depends on !X86_NUMAQ
851 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
852 However, the address space of 32-bit x86 processors is only 4
853 Gigabytes large. That means that, if you have a large amount of
854 physical memory, not all of it can be "permanently mapped" by the
855 kernel. The physical memory that's not permanently mapped is called
858 If you are compiling a kernel which will never run on a machine with
859 more than 1 Gigabyte total physical RAM, answer "off" here (default
860 choice and suitable for most users). This will result in a "3GB/1GB"
861 split: 3GB are mapped so that each process sees a 3GB virtual memory
862 space and the remaining part of the 4GB virtual memory space is used
863 by the kernel to permanently map as much physical memory as
866 If the machine has between 1 and 4 Gigabytes physical RAM, then
869 If more than 4 Gigabytes is used then answer "64GB" here. This
870 selection turns Intel PAE (Physical Address Extension) mode on.
871 PAE implements 3-level paging on IA32 processors. PAE is fully
872 supported by Linux, PAE mode is implemented on all recent Intel
873 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
874 then the kernel will not boot on CPUs that don't support PAE!
876 The actual amount of total physical memory will either be
877 auto detected or can be forced by using a kernel command line option
878 such as "mem=256M". (Try "man bootparam" or see the documentation of
879 your boot loader (lilo or loadlin) about how to pass options to the
880 kernel at boot time.)
882 If unsure, say "off".
886 depends on !X86_NUMAQ
888 Select this if you have a 32-bit processor and between 1 and 4
889 gigabytes of physical RAM.
893 depends on !M386 && !M486
896 Select this if you have a 32-bit processor and more than 4
897 gigabytes of physical RAM.
902 depends on EXPERIMENTAL
903 prompt "Memory split" if EMBEDDED
907 Select the desired split between kernel and user memory.
909 If the address range available to the kernel is less than the
910 physical memory installed, the remaining memory will be available
911 as "high memory". Accessing high memory is a little more costly
912 than low memory, as it needs to be mapped into the kernel first.
913 Note that increasing the kernel address space limits the range
914 available to user programs, making the address space there
915 tighter. Selecting anything other than the default 3G/1G split
916 will also likely make your kernel incompatible with binary-only
919 If you are not absolutely sure what you are doing, leave this
923 bool "3G/1G user/kernel split"
924 config VMSPLIT_3G_OPT
926 bool "3G/1G user/kernel split (for full 1G low memory)"
928 bool "2G/2G user/kernel split"
929 config VMSPLIT_2G_OPT
931 bool "2G/2G user/kernel split (for full 2G low memory)"
933 bool "1G/3G user/kernel split"
938 default 0xB0000000 if VMSPLIT_3G_OPT
939 default 0x80000000 if VMSPLIT_2G
940 default 0x78000000 if VMSPLIT_2G_OPT
941 default 0x40000000 if VMSPLIT_1G
947 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
951 prompt "PAE (Physical Address Extension) Support"
952 depends on X86_32 && !HIGHMEM4G
953 select RESOURCES_64BIT
955 PAE is required for NX support, and furthermore enables
956 larger swapspace support for non-overcommit purposes. It
957 has the cost of more pagetable lookup overhead, and also
958 consumes more pagetable space per process.
960 # Common NUMA Features
962 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
964 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
966 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
968 Enable NUMA (Non Uniform Memory Access) support.
969 The kernel will try to allocate memory used by a CPU on the
970 local memory controller of the CPU and add some more
971 NUMA awareness to the kernel.
973 For 32-bit this is currently highly experimental and should be only
974 used for kernel development. It might also cause boot failures.
975 For 64-bit this is recommended on all multiprocessor Opteron systems.
976 If the system is EM64T, you should say N unless your system is
979 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
980 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
984 prompt "Old style AMD Opteron NUMA detection"
985 depends on X86_64 && NUMA && PCI
987 Enable K8 NUMA node topology detection. You should say Y here if
988 you have a multi processor AMD K8 system. This uses an old
989 method to read the NUMA configuration directly from the builtin
990 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
991 instead, which also takes priority if both are compiled in.
993 config X86_64_ACPI_NUMA
995 prompt "ACPI NUMA detection"
996 depends on X86_64 && NUMA && ACPI && PCI
999 Enable ACPI SRAT based node topology detection.
1001 # Some NUMA nodes have memory ranges that span
1002 # other nodes. Even though a pfn is valid and
1003 # between a node's start and end pfns, it may not
1004 # reside on that node. See memmap_init_zone()
1006 config NODES_SPAN_OTHER_NODES
1008 depends on X86_64_ACPI_NUMA
1011 bool "NUMA emulation"
1012 depends on X86_64 && NUMA
1014 Enable NUMA emulation. A flat machine will be split
1015 into virtual nodes when booted with "numa=fake=N", where N is the
1016 number of nodes. This is only useful for debugging.
1019 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1021 default "9" if MAXSMP
1022 default "6" if X86_64
1023 default "4" if X86_NUMAQ
1025 depends on NEED_MULTIPLE_NODES
1027 Specify the maximum number of NUMA Nodes available on the target
1028 system. Increases memory reserved to accomodate various tables.
1030 config HAVE_ARCH_BOOTMEM_NODE
1032 depends on X86_32 && NUMA
1034 config ARCH_HAVE_MEMORY_PRESENT
1036 depends on X86_32 && DISCONTIGMEM
1038 config NEED_NODE_MEMMAP_SIZE
1040 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1042 config HAVE_ARCH_ALLOC_REMAP
1044 depends on X86_32 && NUMA
1046 config ARCH_FLATMEM_ENABLE
1048 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1050 config ARCH_DISCONTIGMEM_ENABLE
1052 depends on NUMA && X86_32
1054 config ARCH_DISCONTIGMEM_DEFAULT
1056 depends on NUMA && X86_32
1058 config ARCH_SPARSEMEM_DEFAULT
1062 config ARCH_SPARSEMEM_ENABLE
1064 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1065 select SPARSEMEM_STATIC if X86_32
1066 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1068 config ARCH_SELECT_MEMORY_MODEL
1070 depends on ARCH_SPARSEMEM_ENABLE
1072 config ARCH_MEMORY_PROBE
1074 depends on MEMORY_HOTPLUG
1079 bool "Allocate 3rd-level pagetables from highmem"
1080 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1082 The VM uses one page table entry for each page of physical memory.
1083 For systems with a lot of RAM, this can be wasteful of precious
1084 low memory. Setting this option will put user-space page table
1085 entries in high memory.
1087 config X86_CHECK_BIOS_CORRUPTION
1088 bool "Check for low memory corruption"
1090 Periodically check for memory corruption in low memory, which
1091 is suspected to be caused by BIOS. Even when enabled in the
1092 configuration, it is disabled at runtime. Enable it by
1093 setting "memory_corruption_check=1" on the kernel command
1094 line. By default it scans the low 64k of memory every 60
1095 seconds; see the memory_corruption_check_size and
1096 memory_corruption_check_period parameters in
1097 Documentation/kernel-parameters.txt to adjust this.
1099 When enabled with the default parameters, this option has
1100 almost no overhead, as it reserves a relatively small amount
1101 of memory and scans it infrequently. It both detects corruption
1102 and prevents it from affecting the running system.
1104 It is, however, intended as a diagnostic tool; if repeatable
1105 BIOS-originated corruption always affects the same memory,
1106 you can use memmap= to prevent the kernel from using that
1109 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1110 bool "Set the default setting of memory_corruption_check"
1111 depends on X86_CHECK_BIOS_CORRUPTION
1114 Set whether the default state of memory_corruption_check is
1117 config X86_RESERVE_LOW_64K
1118 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1121 Reserve the first 64K of physical RAM on BIOSes that are known
1122 to potentially corrupt that memory range. A numbers of BIOSes are
1123 known to utilize this area during suspend/resume, so it must not
1124 be used by the kernel.
1126 Set this to N if you are absolutely sure that you trust the BIOS
1127 to get all its memory reservations and usages right.
1129 If you have doubts about the BIOS (e.g. suspend/resume does not
1130 work or there's kernel crashes after certain hardware hotplug
1131 events) and it's not AMI or Phoenix, then you might want to enable
1132 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1133 corruption patterns.
1137 config MATH_EMULATION
1139 prompt "Math emulation" if X86_32
1141 Linux can emulate a math coprocessor (used for floating point
1142 operations) if you don't have one. 486DX and Pentium processors have
1143 a math coprocessor built in, 486SX and 386 do not, unless you added
1144 a 487DX or 387, respectively. (The messages during boot time can
1145 give you some hints here ["man dmesg"].) Everyone needs either a
1146 coprocessor or this emulation.
1148 If you don't have a math coprocessor, you need to say Y here; if you
1149 say Y here even though you have a coprocessor, the coprocessor will
1150 be used nevertheless. (This behavior can be changed with the kernel
1151 command line option "no387", which comes handy if your coprocessor
1152 is broken. Try "man bootparam" or see the documentation of your boot
1153 loader (lilo or loadlin) about how to pass options to the kernel at
1154 boot time.) This means that it is a good idea to say Y here if you
1155 intend to use this kernel on different machines.
1157 More information about the internals of the Linux math coprocessor
1158 emulation can be found in <file:arch/x86/math-emu/README>.
1160 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1161 kernel, it won't hurt.
1164 bool "MTRR (Memory Type Range Register) support"
1166 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1167 the Memory Type Range Registers (MTRRs) may be used to control
1168 processor access to memory ranges. This is most useful if you have
1169 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1170 allows bus write transfers to be combined into a larger transfer
1171 before bursting over the PCI/AGP bus. This can increase performance
1172 of image write operations 2.5 times or more. Saying Y here creates a
1173 /proc/mtrr file which may be used to manipulate your processor's
1174 MTRRs. Typically the X server should use this.
1176 This code has a reasonably generic interface so that similar
1177 control registers on other processors can be easily supported
1180 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1181 Registers (ARRs) which provide a similar functionality to MTRRs. For
1182 these, the ARRs are used to emulate the MTRRs.
1183 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1184 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1185 write-combining. All of these processors are supported by this code
1186 and it makes sense to say Y here if you have one of them.
1188 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1189 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1190 can lead to all sorts of problems, so it's good to say Y here.
1192 You can safely say Y even if your machine doesn't have MTRRs, you'll
1193 just add about 9 KB to your kernel.
1195 See <file:Documentation/x86/mtrr.txt> for more information.
1197 config MTRR_SANITIZER
1199 prompt "MTRR cleanup support"
1202 Convert MTRR layout from continuous to discrete, so X drivers can
1203 add writeback entries.
1205 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1206 The largest mtrr entry size for a continous block can be set with
1211 config MTRR_SANITIZER_ENABLE_DEFAULT
1212 int "MTRR cleanup enable value (0-1)"
1215 depends on MTRR_SANITIZER
1217 Enable mtrr cleanup default value
1219 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1220 int "MTRR cleanup spare reg num (0-7)"
1223 depends on MTRR_SANITIZER
1225 mtrr cleanup spare entries default, it can be changed via
1226 mtrr_spare_reg_nr=N on the kernel command line.
1230 prompt "x86 PAT support"
1233 Use PAT attributes to setup page level cache control.
1235 PATs are the modern equivalents of MTRRs and are much more
1236 flexible than MTRRs.
1238 Say N here if you see bootup problems (boot crash, boot hang,
1239 spontaneous reboots) or a non-working video driver.
1245 prompt "EFI runtime service support"
1248 This enables the kernel to use EFI runtime services that are
1249 available (such as the EFI variable services).
1251 This option is only useful on systems that have EFI firmware.
1252 In addition, you should use the latest ELILO loader available
1253 at <http://elilo.sourceforge.net> in order to take advantage
1254 of EFI runtime services. However, even with this option, the
1255 resultant kernel should continue to boot on existing non-EFI
1260 prompt "Enable kernel irq balancing"
1261 depends on X86_32 && SMP && X86_IO_APIC
1263 The default yes will allow the kernel to do irq load balancing.
1264 Saying no will keep the kernel from doing irq load balancing.
1268 prompt "Enable seccomp to safely compute untrusted bytecode"
1270 This kernel feature is useful for number crunching applications
1271 that may need to compute untrusted bytecode during their
1272 execution. By using pipes or other transports made available to
1273 the process as file descriptors supporting the read/write
1274 syscalls, it's possible to isolate those applications in
1275 their own address space using seccomp. Once seccomp is
1276 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1277 and the task is only allowed to execute a few safe syscalls
1278 defined by each seccomp mode.
1280 If unsure, say Y. Only embedded should say N here.
1282 config CC_STACKPROTECTOR
1283 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1284 depends on X86_64 && EXPERIMENTAL && BROKEN
1286 This option turns on the -fstack-protector GCC feature. This
1287 feature puts, at the beginning of critical functions, a canary
1288 value on the stack just before the return address, and validates
1289 the value just before actually returning. Stack based buffer
1290 overflows (that need to overwrite this return address) now also
1291 overwrite the canary, which gets detected and the attack is then
1292 neutralized via a kernel panic.
1294 This feature requires gcc version 4.2 or above, or a distribution
1295 gcc with the feature backported. Older versions are automatically
1296 detected and for those versions, this configuration option is ignored.
1298 config CC_STACKPROTECTOR_ALL
1299 bool "Use stack-protector for all functions"
1300 depends on CC_STACKPROTECTOR
1302 Normally, GCC only inserts the canary value protection for
1303 functions that use large-ish on-stack buffers. By enabling
1304 this option, GCC will be asked to do this for ALL functions.
1306 source kernel/Kconfig.hz
1309 bool "kexec system call"
1310 depends on X86_BIOS_REBOOT
1312 kexec is a system call that implements the ability to shutdown your
1313 current kernel, and to start another kernel. It is like a reboot
1314 but it is independent of the system firmware. And like a reboot
1315 you can start any kernel with it, not just Linux.
1317 The name comes from the similarity to the exec system call.
1319 It is an ongoing process to be certain the hardware in a machine
1320 is properly shutdown, so do not be surprised if this code does not
1321 initially work for you. It may help to enable device hotplugging
1322 support. As of this writing the exact hardware interface is
1323 strongly in flux, so no good recommendation can be made.
1326 bool "kernel crash dumps"
1327 depends on X86_64 || (X86_32 && HIGHMEM)
1329 Generate crash dump after being started by kexec.
1330 This should be normally only set in special crash dump kernels
1331 which are loaded in the main kernel with kexec-tools into
1332 a specially reserved region and then later executed after
1333 a crash by kdump/kexec. The crash dump kernel must be compiled
1334 to a memory address not used by the main kernel or BIOS using
1335 PHYSICAL_START, or it must be built as a relocatable image
1336 (CONFIG_RELOCATABLE=y).
1337 For more details see Documentation/kdump/kdump.txt
1340 bool "kexec jump (EXPERIMENTAL)"
1341 depends on EXPERIMENTAL
1342 depends on KEXEC && HIBERNATION && X86_32
1344 Jump between original kernel and kexeced kernel and invoke
1345 code in physical address mode via KEXEC
1347 config PHYSICAL_START
1348 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1349 default "0x1000000" if X86_NUMAQ
1350 default "0x200000" if X86_64
1353 This gives the physical address where the kernel is loaded.
1355 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1356 bzImage will decompress itself to above physical address and
1357 run from there. Otherwise, bzImage will run from the address where
1358 it has been loaded by the boot loader and will ignore above physical
1361 In normal kdump cases one does not have to set/change this option
1362 as now bzImage can be compiled as a completely relocatable image
1363 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1364 address. This option is mainly useful for the folks who don't want
1365 to use a bzImage for capturing the crash dump and want to use a
1366 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1367 to be specifically compiled to run from a specific memory area
1368 (normally a reserved region) and this option comes handy.
1370 So if you are using bzImage for capturing the crash dump, leave
1371 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1372 Otherwise if you plan to use vmlinux for capturing the crash dump
1373 change this value to start of the reserved region (Typically 16MB
1374 0x1000000). In other words, it can be set based on the "X" value as
1375 specified in the "crashkernel=YM@XM" command line boot parameter
1376 passed to the panic-ed kernel. Typically this parameter is set as
1377 crashkernel=64M@16M. Please take a look at
1378 Documentation/kdump/kdump.txt for more details about crash dumps.
1380 Usage of bzImage for capturing the crash dump is recommended as
1381 one does not have to build two kernels. Same kernel can be used
1382 as production kernel and capture kernel. Above option should have
1383 gone away after relocatable bzImage support is introduced. But it
1384 is present because there are users out there who continue to use
1385 vmlinux for dump capture. This option should go away down the
1388 Don't change this unless you know what you are doing.
1391 bool "Build a relocatable kernel (EXPERIMENTAL)"
1392 depends on EXPERIMENTAL
1394 This builds a kernel image that retains relocation information
1395 so it can be loaded someplace besides the default 1MB.
1396 The relocations tend to make the kernel binary about 10% larger,
1397 but are discarded at runtime.
1399 One use is for the kexec on panic case where the recovery kernel
1400 must live at a different physical address than the primary
1403 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1404 it has been loaded at and the compile time physical address
1405 (CONFIG_PHYSICAL_START) is ignored.
1407 config PHYSICAL_ALIGN
1409 prompt "Alignment value to which kernel should be aligned" if X86_32
1410 default "0x100000" if X86_32
1411 default "0x200000" if X86_64
1412 range 0x2000 0x400000
1414 This value puts the alignment restrictions on physical address
1415 where kernel is loaded and run from. Kernel is compiled for an
1416 address which meets above alignment restriction.
1418 If bootloader loads the kernel at a non-aligned address and
1419 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1420 address aligned to above value and run from there.
1422 If bootloader loads the kernel at a non-aligned address and
1423 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1424 load address and decompress itself to the address it has been
1425 compiled for and run from there. The address for which kernel is
1426 compiled already meets above alignment restrictions. Hence the
1427 end result is that kernel runs from a physical address meeting
1428 above alignment restrictions.
1430 Don't change this unless you know what you are doing.
1433 bool "Support for hot-pluggable CPUs"
1434 depends on SMP && HOTPLUG && !X86_VOYAGER
1436 Say Y here to allow turning CPUs off and on. CPUs can be
1437 controlled through /sys/devices/system/cpu.
1438 ( Note: power management support will enable this option
1439 automatically on SMP systems. )
1440 Say N if you want to disable CPU hotplug.
1444 prompt "Compat VDSO support"
1445 depends on X86_32 || IA32_EMULATION
1447 Map the 32-bit VDSO to the predictable old-style address too.
1449 Say N here if you are running a sufficiently recent glibc
1450 version (2.3.3 or later), to remove the high-mapped
1451 VDSO mapping and to exclusively use the randomized VDSO.
1456 bool "Built-in kernel command line"
1459 Allow for specifying boot arguments to the kernel at
1460 build time. On some systems (e.g. embedded ones), it is
1461 necessary or convenient to provide some or all of the
1462 kernel boot arguments with the kernel itself (that is,
1463 to not rely on the boot loader to provide them.)
1465 To compile command line arguments into the kernel,
1466 set this option to 'Y', then fill in the
1467 the boot arguments in CONFIG_CMDLINE.
1469 Systems with fully functional boot loaders (i.e. non-embedded)
1470 should leave this option set to 'N'.
1473 string "Built-in kernel command string"
1474 depends on CMDLINE_BOOL
1477 Enter arguments here that should be compiled into the kernel
1478 image and used at boot time. If the boot loader provides a
1479 command line at boot time, it is appended to this string to
1480 form the full kernel command line, when the system boots.
1482 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1483 change this behavior.
1485 In most cases, the command line (whether built-in or provided
1486 by the boot loader) should specify the device for the root
1489 config CMDLINE_OVERRIDE
1490 bool "Built-in command line overrides boot loader arguments"
1492 depends on CMDLINE_BOOL
1494 Set this option to 'Y' to have the kernel ignore the boot loader
1495 command line, and use ONLY the built-in command line.
1497 This is used to work around broken boot loaders. This should
1498 be set to 'N' under normal conditions.
1502 config ARCH_ENABLE_MEMORY_HOTPLUG
1504 depends on X86_64 || (X86_32 && HIGHMEM)
1506 config HAVE_ARCH_EARLY_PFN_TO_NID
1510 menu "Power management options"
1511 depends on !X86_VOYAGER
1513 config ARCH_HIBERNATION_HEADER
1515 depends on X86_64 && HIBERNATION
1517 source "kernel/power/Kconfig"
1519 source "drivers/acpi/Kconfig"
1524 depends on APM || APM_MODULE
1527 tristate "APM (Advanced Power Management) BIOS support"
1528 depends on X86_32 && PM_SLEEP
1530 APM is a BIOS specification for saving power using several different
1531 techniques. This is mostly useful for battery powered laptops with
1532 APM compliant BIOSes. If you say Y here, the system time will be
1533 reset after a RESUME operation, the /proc/apm device will provide
1534 battery status information, and user-space programs will receive
1535 notification of APM "events" (e.g. battery status change).
1537 If you select "Y" here, you can disable actual use of the APM
1538 BIOS by passing the "apm=off" option to the kernel at boot time.
1540 Note that the APM support is almost completely disabled for
1541 machines with more than one CPU.
1543 In order to use APM, you will need supporting software. For location
1544 and more information, read <file:Documentation/power/pm.txt> and the
1545 Battery Powered Linux mini-HOWTO, available from
1546 <http://www.tldp.org/docs.html#howto>.
1548 This driver does not spin down disk drives (see the hdparm(8)
1549 manpage ("man 8 hdparm") for that), and it doesn't turn off
1550 VESA-compliant "green" monitors.
1552 This driver does not support the TI 4000M TravelMate and the ACER
1553 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1554 desktop machines also don't have compliant BIOSes, and this driver
1555 may cause those machines to panic during the boot phase.
1557 Generally, if you don't have a battery in your machine, there isn't
1558 much point in using this driver and you should say N. If you get
1559 random kernel OOPSes or reboots that don't seem to be related to
1560 anything, try disabling/enabling this option (or disabling/enabling
1563 Some other things you should try when experiencing seemingly random,
1566 1) make sure that you have enough swap space and that it is
1568 2) pass the "no-hlt" option to the kernel
1569 3) switch on floating point emulation in the kernel and pass
1570 the "no387" option to the kernel
1571 4) pass the "floppy=nodma" option to the kernel
1572 5) pass the "mem=4M" option to the kernel (thereby disabling
1573 all but the first 4 MB of RAM)
1574 6) make sure that the CPU is not over clocked.
1575 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1576 8) disable the cache from your BIOS settings
1577 9) install a fan for the video card or exchange video RAM
1578 10) install a better fan for the CPU
1579 11) exchange RAM chips
1580 12) exchange the motherboard.
1582 To compile this driver as a module, choose M here: the
1583 module will be called apm.
1587 config APM_IGNORE_USER_SUSPEND
1588 bool "Ignore USER SUSPEND"
1590 This option will ignore USER SUSPEND requests. On machines with a
1591 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1592 series notebooks, it is necessary to say Y because of a BIOS bug.
1594 config APM_DO_ENABLE
1595 bool "Enable PM at boot time"
1597 Enable APM features at boot time. From page 36 of the APM BIOS
1598 specification: "When disabled, the APM BIOS does not automatically
1599 power manage devices, enter the Standby State, enter the Suspend
1600 State, or take power saving steps in response to CPU Idle calls."
1601 This driver will make CPU Idle calls when Linux is idle (unless this
1602 feature is turned off -- see "Do CPU IDLE calls", below). This
1603 should always save battery power, but more complicated APM features
1604 will be dependent on your BIOS implementation. You may need to turn
1605 this option off if your computer hangs at boot time when using APM
1606 support, or if it beeps continuously instead of suspending. Turn
1607 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1608 T400CDT. This is off by default since most machines do fine without
1612 bool "Make CPU Idle calls when idle"
1614 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1615 On some machines, this can activate improved power savings, such as
1616 a slowed CPU clock rate, when the machine is idle. These idle calls
1617 are made after the idle loop has run for some length of time (e.g.,
1618 333 mS). On some machines, this will cause a hang at boot time or
1619 whenever the CPU becomes idle. (On machines with more than one CPU,
1620 this option does nothing.)
1622 config APM_DISPLAY_BLANK
1623 bool "Enable console blanking using APM"
1625 Enable console blanking using the APM. Some laptops can use this to
1626 turn off the LCD backlight when the screen blanker of the Linux
1627 virtual console blanks the screen. Note that this is only used by
1628 the virtual console screen blanker, and won't turn off the backlight
1629 when using the X Window system. This also doesn't have anything to
1630 do with your VESA-compliant power-saving monitor. Further, this
1631 option doesn't work for all laptops -- it might not turn off your
1632 backlight at all, or it might print a lot of errors to the console,
1633 especially if you are using gpm.
1635 config APM_ALLOW_INTS
1636 bool "Allow interrupts during APM BIOS calls"
1638 Normally we disable external interrupts while we are making calls to
1639 the APM BIOS as a measure to lessen the effects of a badly behaving
1640 BIOS implementation. The BIOS should reenable interrupts if it
1641 needs to. Unfortunately, some BIOSes do not -- especially those in
1642 many of the newer IBM Thinkpads. If you experience hangs when you
1643 suspend, try setting this to Y. Otherwise, say N.
1645 config APM_REAL_MODE_POWER_OFF
1646 bool "Use real mode APM BIOS call to power off"
1648 Use real mode APM BIOS calls to switch off the computer. This is
1649 a work-around for a number of buggy BIOSes. Switch this option on if
1650 your computer crashes instead of powering off properly.
1654 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1656 source "drivers/cpuidle/Kconfig"
1661 menu "Bus options (PCI etc.)"
1666 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1668 Find out whether you have a PCI motherboard. PCI is the name of a
1669 bus system, i.e. the way the CPU talks to the other stuff inside
1670 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1671 VESA. If you have PCI, say Y, otherwise N.
1674 prompt "PCI access mode"
1675 depends on X86_32 && PCI
1678 On PCI systems, the BIOS can be used to detect the PCI devices and
1679 determine their configuration. However, some old PCI motherboards
1680 have BIOS bugs and may crash if this is done. Also, some embedded
1681 PCI-based systems don't have any BIOS at all. Linux can also try to
1682 detect the PCI hardware directly without using the BIOS.
1684 With this option, you can specify how Linux should detect the
1685 PCI devices. If you choose "BIOS", the BIOS will be used,
1686 if you choose "Direct", the BIOS won't be used, and if you
1687 choose "MMConfig", then PCI Express MMCONFIG will be used.
1688 If you choose "Any", the kernel will try MMCONFIG, then the
1689 direct access method and falls back to the BIOS if that doesn't
1690 work. If unsure, go with the default, which is "Any".
1695 config PCI_GOMMCONFIG
1712 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1714 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1717 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1721 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1725 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1732 bool "Support mmconfig PCI config space access"
1733 depends on X86_64 && PCI && ACPI
1736 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1737 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1739 DMA remapping (DMAR) devices support enables independent address
1740 translations for Direct Memory Access (DMA) from devices.
1741 These DMA remapping devices are reported via ACPI tables
1742 and include PCI device scope covered by these DMA
1747 prompt "Support for Graphics workaround"
1750 Current Graphics drivers tend to use physical address
1751 for DMA and avoid using DMA APIs. Setting this config
1752 option permits the IOMMU driver to set a unity map for
1753 all the OS-visible memory. Hence the driver can continue
1754 to use physical addresses for DMA.
1756 config DMAR_FLOPPY_WA
1760 Floppy disk drivers are know to bypass DMA API calls
1761 thereby failing to work when IOMMU is enabled. This
1762 workaround will setup a 1:1 mapping for the first
1763 16M to make floppy (an ISA device) work.
1766 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1767 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1769 Supports Interrupt remapping for IO-APIC and MSI devices.
1770 To use x2apic mode in the CPU's which support x2APIC enhancements or
1771 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1773 source "drivers/pci/pcie/Kconfig"
1775 source "drivers/pci/Kconfig"
1777 # x86_64 have no ISA slots, but do have ISA-style DMA.
1785 depends on !X86_VOYAGER
1787 Find out whether you have ISA slots on your motherboard. ISA is the
1788 name of a bus system, i.e. the way the CPU talks to the other stuff
1789 inside your box. Other bus systems are PCI, EISA, MicroChannel
1790 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1791 newer boards don't support it. If you have ISA, say Y, otherwise N.
1797 The Extended Industry Standard Architecture (EISA) bus was
1798 developed as an open alternative to the IBM MicroChannel bus.
1800 The EISA bus provided some of the features of the IBM MicroChannel
1801 bus while maintaining backward compatibility with cards made for
1802 the older ISA bus. The EISA bus saw limited use between 1988 and
1803 1995 when it was made obsolete by the PCI bus.
1805 Say Y here if you are building a kernel for an EISA-based machine.
1809 source "drivers/eisa/Kconfig"
1812 bool "MCA support" if !X86_VOYAGER
1813 default y if X86_VOYAGER
1815 MicroChannel Architecture is found in some IBM PS/2 machines and
1816 laptops. It is a bus system similar to PCI or ISA. See
1817 <file:Documentation/mca.txt> (and especially the web page given
1818 there) before attempting to build an MCA bus kernel.
1820 source "drivers/mca/Kconfig"
1823 tristate "NatSemi SCx200 support"
1824 depends on !X86_VOYAGER
1826 This provides basic support for National Semiconductor's
1827 (now AMD's) Geode processors. The driver probes for the
1828 PCI-IDs of several on-chip devices, so its a good dependency
1829 for other scx200_* drivers.
1831 If compiled as a module, the driver is named scx200.
1833 config SCx200HR_TIMER
1834 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1835 depends on SCx200 && GENERIC_TIME
1838 This driver provides a clocksource built upon the on-chip
1839 27MHz high-resolution timer. Its also a workaround for
1840 NSC Geode SC-1100's buggy TSC, which loses time when the
1841 processor goes idle (as is done by the scheduler). The
1842 other workaround is idle=poll boot option.
1844 config GEODE_MFGPT_TIMER
1846 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1847 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1849 This driver provides a clock event source based on the MFGPT
1850 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1851 MFGPTs have a better resolution and max interval than the
1852 generic PIT, and are suitable for use as high-res timers.
1855 bool "One Laptop Per Child support"
1858 Add support for detecting the unique features of the OLPC
1865 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1867 source "drivers/pcmcia/Kconfig"
1869 source "drivers/pci/hotplug/Kconfig"
1874 menu "Executable file formats / Emulations"
1876 source "fs/Kconfig.binfmt"
1878 config IA32_EMULATION
1879 bool "IA32 Emulation"
1881 select COMPAT_BINFMT_ELF
1883 Include code to run 32-bit programs under a 64-bit kernel. You should
1884 likely turn this on, unless you're 100% sure that you don't have any
1885 32-bit programs left.
1888 tristate "IA32 a.out support"
1889 depends on IA32_EMULATION && ARCH_SUPPORTS_AOUT
1891 Support old a.out binaries in the 32bit emulation.
1895 depends on IA32_EMULATION
1897 config COMPAT_FOR_U64_ALIGNMENT
1901 config SYSVIPC_COMPAT
1903 depends on COMPAT && SYSVIPC
1908 source "net/Kconfig"
1910 source "drivers/Kconfig"
1912 source "drivers/firmware/Kconfig"
1916 source "arch/x86/Kconfig.debug"
1918 source "security/Kconfig"
1920 source "crypto/Kconfig"
1922 source "arch/x86/kvm/Kconfig"
1924 source "lib/Kconfig"
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