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
241 config X86_FIND_SMP_CONFIG
243 depends on X86_MPPARSE || X86_VOYAGER
248 bool "Enable MPS table"
249 depends on X86_LOCAL_APIC
251 For old smp systems that do not have proper acpi support. Newer systems
252 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
258 depends on X86_LOCAL_APIC
262 prompt "Subarchitecture Type"
268 Choose this option if your computer is a standard PC or compatible.
274 Select this for an AMD Elan processor.
276 Do not use this option for K6/Athlon/Opteron processors!
278 If unsure, choose "PC-compatible" instead.
282 depends on X86_32 && (SMP || BROKEN) && !PCI
284 Voyager is an MCA-based 32-way capable SMP architecture proprietary
285 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
289 If you do not specifically know you have a Voyager based machine,
290 say N here, otherwise the kernel you build will not be bootable.
292 config X86_GENERICARCH
293 bool "Generic architecture"
296 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
297 subarchitectures. It is intended for a generic binary kernel.
298 if you select them all, kernel will probe it one by one. and will
304 bool "NUMAQ (IBM/Sequent)"
305 depends on SMP && X86_32 && PCI && X86_MPPARSE
308 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
309 NUMA multiquad box. This changes the way that processors are
310 bootstrapped, and uses Clustered Logical APIC addressing mode instead
311 of Flat Logical. You will need a new lynxer.elf file to flash your
312 firmware with - send email to <Martin.Bligh@us.ibm.com>.
315 bool "Summit/EXA (IBM x440)"
316 depends on X86_32 && SMP
318 This option is needed for IBM systems that use the Summit/EXA chipset.
319 In particular, it is needed for the x440.
322 bool "Support for Unisys ES7000 IA32 series"
323 depends on X86_32 && SMP
325 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
326 supposed to run on an IA32-based Unisys ES7000 system.
329 bool "Support for big SMP systems with more than 8 CPUs"
330 depends on X86_32 && SMP
332 This option is needed for the systems that have more than 8 CPUs
333 and if the system is not of any sub-arch type above.
338 bool "Support for ScaleMP vSMP"
340 depends on X86_64 && PCI
342 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
343 supposed to run on these EM64T-based machines. Only choose this option
344 if you have one of these machines.
349 bool "SGI 320/540 (Visual Workstation)"
350 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
352 The SGI Visual Workstation series is an IA32-based workstation
353 based on SGI systems chips with some legacy PC hardware attached.
355 Say Y here to create a kernel to run on the SGI 320 or 540.
357 A kernel compiled for the Visual Workstation will run on general
358 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
361 bool "RDC R-321x SoC"
364 select X86_REBOOTFIXUPS
366 This option is needed for RDC R-321x system-on-chip, also known
368 If you don't have one of these chips, you should say N here.
370 config SCHED_NO_NO_OMIT_FRAME_POINTER
372 prompt "Single-depth WCHAN output"
375 Calculate simpler /proc/<PID>/wchan values. If this option
376 is disabled then wchan values will recurse back to the
377 caller function. This provides more accurate wchan values,
378 at the expense of slightly more scheduling overhead.
380 If in doubt, say "Y".
382 menuconfig PARAVIRT_GUEST
383 bool "Paravirtualized guest support"
385 Say Y here to get to see options related to running Linux under
386 various hypervisors. This option alone does not add any kernel code.
388 If you say N, all options in this submenu will be skipped and disabled.
392 source "arch/x86/xen/Kconfig"
395 bool "VMI Guest support"
398 depends on !X86_VOYAGER
400 VMI provides a paravirtualized interface to the VMware ESX server
401 (it could be used by other hypervisors in theory too, but is not
402 at the moment), by linking the kernel to a GPL-ed ROM module
403 provided by the hypervisor.
406 bool "KVM paravirtualized clock"
408 select PARAVIRT_CLOCK
409 depends on !X86_VOYAGER
411 Turning on this option will allow you to run a paravirtualized clock
412 when running over the KVM hypervisor. Instead of relying on a PIT
413 (or probably other) emulation by the underlying device model, the host
414 provides the guest with timing infrastructure such as time of day, and
418 bool "KVM Guest support"
420 depends on !X86_VOYAGER
422 This option enables various optimizations for running under the KVM
425 source "arch/x86/lguest/Kconfig"
428 bool "Enable paravirtualization code"
429 depends on !X86_VOYAGER
431 This changes the kernel so it can modify itself when it is run
432 under a hypervisor, potentially improving performance significantly
433 over full virtualization. However, when run without a hypervisor
434 the kernel is theoretically slower and slightly larger.
436 config PARAVIRT_CLOCK
442 config PARAVIRT_DEBUG
443 bool "paravirt-ops debugging"
444 depends on PARAVIRT && DEBUG_KERNEL
446 Enable to debug paravirt_ops internals. Specifically, BUG if
447 a paravirt_op is missing when it is called.
452 This option adds a kernel parameter 'memtest', which allows memtest
454 memtest=0, mean disabled; -- default
455 memtest=1, mean do 1 test pattern;
457 memtest=4, mean do 4 test patterns.
458 If you are unsure how to answer this question, answer N.
460 config X86_SUMMIT_NUMA
462 depends on X86_32 && NUMA && X86_GENERICARCH
464 config X86_CYCLONE_TIMER
466 depends on X86_GENERICARCH
468 source "arch/x86/Kconfig.cpu"
472 prompt "HPET Timer Support" if X86_32
474 Use the IA-PC HPET (High Precision Event Timer) to manage
475 time in preference to the PIT and RTC, if a HPET is
477 HPET is the next generation timer replacing legacy 8254s.
478 The HPET provides a stable time base on SMP
479 systems, unlike the TSC, but it is more expensive to access,
480 as it is off-chip. You can find the HPET spec at
481 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
483 You can safely choose Y here. However, HPET will only be
484 activated if the platform and the BIOS support this feature.
485 Otherwise the 8254 will be used for timing services.
487 Choose N to continue using the legacy 8254 timer.
489 config HPET_EMULATE_RTC
491 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
493 # Mark as embedded because too many people got it wrong.
494 # The code disables itself when not needed.
497 bool "Enable DMI scanning" if EMBEDDED
499 Enabled scanning of DMI to identify machine quirks. Say Y
500 here unless you have verified that your setup is not
501 affected by entries in the DMI blacklist. Required by PNP
505 bool "GART IOMMU support" if EMBEDDED
509 depends on X86_64 && PCI
511 Support for full DMA access of devices with 32bit memory access only
512 on systems with more than 3GB. This is usually needed for USB,
513 sound, many IDE/SATA chipsets and some other devices.
514 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
515 based hardware IOMMU and a software bounce buffer based IOMMU used
516 on Intel systems and as fallback.
517 The code is only active when needed (enough memory and limited
518 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
522 bool "IBM Calgary IOMMU support"
524 depends on X86_64 && PCI && EXPERIMENTAL
526 Support for hardware IOMMUs in IBM's xSeries x366 and x460
527 systems. Needed to run systems with more than 3GB of memory
528 properly with 32-bit PCI devices that do not support DAC
529 (Double Address Cycle). Calgary also supports bus level
530 isolation, where all DMAs pass through the IOMMU. This
531 prevents them from going anywhere except their intended
532 destination. This catches hard-to-find kernel bugs and
533 mis-behaving drivers and devices that do not use the DMA-API
534 properly to set up their DMA buffers. The IOMMU can be
535 turned off at boot time with the iommu=off parameter.
536 Normally the kernel will make the right choice by itself.
539 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
541 prompt "Should Calgary be enabled by default?"
542 depends on CALGARY_IOMMU
544 Should Calgary be enabled by default? if you choose 'y', Calgary
545 will be used (if it exists). If you choose 'n', Calgary will not be
546 used even if it exists. If you choose 'n' and would like to use
547 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
551 bool "AMD IOMMU support"
554 depends on X86_64 && PCI && ACPI
556 With this option you can enable support for AMD IOMMU hardware in
557 your system. An IOMMU is a hardware component which provides
558 remapping of DMA memory accesses from devices. With an AMD IOMMU you
559 can isolate the the DMA memory of different devices and protect the
560 system from misbehaving device drivers or hardware.
562 You can find out if your system has an AMD IOMMU if you look into
563 your BIOS for an option to enable it or if you have an IVRS ACPI
566 # need this always selected by IOMMU for the VIA workaround
570 Support for software bounce buffers used on x86-64 systems
571 which don't have a hardware IOMMU (e.g. the current generation
572 of Intel's x86-64 CPUs). Using this PCI devices which can only
573 access 32-bits of memory can be used on systems with more than
574 3 GB of memory. If unsure, say Y.
577 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
580 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
581 depends on X86_64 && SMP && BROKEN
584 Configure maximum number of CPUS and NUMA Nodes for this architecture.
588 int "Maximum number of CPUs (2-512)" if !MAXSMP
591 default "4096" if MAXSMP
592 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
595 This allows you to specify the maximum number of CPUs which this
596 kernel will support. The maximum supported value is 512 and the
597 minimum value which makes sense is 2.
599 This is purely to save memory - each supported CPU adds
600 approximately eight kilobytes to the kernel image.
603 bool "SMT (Hyperthreading) scheduler support"
606 SMT scheduler support improves the CPU scheduler's decision making
607 when dealing with Intel Pentium 4 chips with HyperThreading at a
608 cost of slightly increased overhead in some places. If unsure say
613 prompt "Multi-core scheduler support"
616 Multi-core scheduler support improves the CPU scheduler's decision
617 making when dealing with multi-core CPU chips at a cost of slightly
618 increased overhead in some places. If unsure say N here.
620 source "kernel/Kconfig.preempt"
623 bool "Local APIC support on uniprocessors"
624 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
626 A local APIC (Advanced Programmable Interrupt Controller) is an
627 integrated interrupt controller in the CPU. If you have a single-CPU
628 system which has a processor with a local APIC, you can say Y here to
629 enable and use it. If you say Y here even though your machine doesn't
630 have a local APIC, then the kernel will still run with no slowdown at
631 all. The local APIC supports CPU-generated self-interrupts (timer,
632 performance counters), and the NMI watchdog which detects hard
636 bool "IO-APIC support on uniprocessors"
637 depends on X86_UP_APIC
639 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
640 SMP-capable replacement for PC-style interrupt controllers. Most
641 SMP systems and many recent uniprocessor systems have one.
643 If you have a single-CPU system with an IO-APIC, you can say Y here
644 to use it. If you say Y here even though your machine doesn't have
645 an IO-APIC, then the kernel will still run with no slowdown at all.
647 config X86_LOCAL_APIC
649 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
653 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
655 config X86_VISWS_APIC
657 depends on X86_32 && X86_VISWS
660 bool "Machine Check Exception"
661 depends on !X86_VOYAGER
663 Machine Check Exception support allows the processor to notify the
664 kernel if it detects a problem (e.g. overheating, component failure).
665 The action the kernel takes depends on the severity of the problem,
666 ranging from a warning message on the console, to halting the machine.
667 Your processor must be a Pentium or newer to support this - check the
668 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
669 have a design flaw which leads to false MCE events - hence MCE is
670 disabled on all P5 processors, unless explicitly enabled with "mce"
671 as a boot argument. Similarly, if MCE is built in and creates a
672 problem on some new non-standard machine, you can boot with "nomce"
673 to disable it. MCE support simply ignores non-MCE processors like
674 the 386 and 486, so nearly everyone can say Y here.
678 prompt "Intel MCE features"
679 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
681 Additional support for intel specific MCE features such as
686 prompt "AMD MCE features"
687 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
689 Additional support for AMD specific MCE features such as
690 the DRAM Error Threshold.
692 config X86_MCE_NONFATAL
693 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
694 depends on X86_32 && X86_MCE
696 Enabling this feature starts a timer that triggers every 5 seconds which
697 will look at the machine check registers to see if anything happened.
698 Non-fatal problems automatically get corrected (but still logged).
699 Disable this if you don't want to see these messages.
700 Seeing the messages this option prints out may be indicative of dying
701 or out-of-spec (ie, overclocked) hardware.
702 This option only does something on certain CPUs.
703 (AMD Athlon/Duron and Intel Pentium 4)
705 config X86_MCE_P4THERMAL
706 bool "check for P4 thermal throttling interrupt."
707 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
709 Enabling this feature will cause a message to be printed when the P4
710 enters thermal throttling.
713 bool "Enable VM86 support" if EMBEDDED
717 This option is required by programs like DOSEMU to run 16-bit legacy
718 code on X86 processors. It also may be needed by software like
719 XFree86 to initialize some video cards via BIOS. Disabling this
720 option saves about 6k.
723 tristate "Toshiba Laptop support"
726 This adds a driver to safely access the System Management Mode of
727 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
728 not work on models with a Phoenix BIOS. The System Management Mode
729 is used to set the BIOS and power saving options on Toshiba portables.
731 For information on utilities to make use of this driver see the
732 Toshiba Linux utilities web site at:
733 <http://www.buzzard.org.uk/toshiba/>.
735 Say Y if you intend to run this kernel on a Toshiba portable.
739 tristate "Dell laptop support"
741 This adds a driver to safely access the System Management Mode
742 of the CPU on the Dell Inspiron 8000. The System Management Mode
743 is used to read cpu temperature and cooling fan status and to
744 control the fans on the I8K portables.
746 This driver has been tested only on the Inspiron 8000 but it may
747 also work with other Dell laptops. You can force loading on other
748 models by passing the parameter `force=1' to the module. Use at
751 For information on utilities to make use of this driver see the
752 I8K Linux utilities web site at:
753 <http://people.debian.org/~dz/i8k/>
755 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
758 config X86_REBOOTFIXUPS
759 bool "Enable X86 board specific fixups for reboot"
762 This enables chipset and/or board specific fixups to be done
763 in order to get reboot to work correctly. This is only needed on
764 some combinations of hardware and BIOS. The symptom, for which
765 this config is intended, is when reboot ends with a stalled/hung
768 Currently, the only fixup is for the Geode machines using
769 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
771 Say Y if you want to enable the fixup. Currently, it's safe to
772 enable this option even if you don't need it.
776 tristate "/dev/cpu/microcode - microcode support"
779 If you say Y here, you will be able to update the microcode on
780 certain Intel and AMD processors. The Intel support is for the
781 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
782 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
783 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
784 You will obviously need the actual microcode binary data itself
785 which is not shipped with the Linux kernel.
787 This option selects the general module only, you need to select
788 at least one vendor specific module as well.
790 To compile this driver as a module, choose M here: the
791 module will be called microcode.
793 config MICROCODE_INTEL
794 bool "Intel microcode patch loading support"
799 This options enables microcode patch loading support for Intel
802 For latest news and information on obtaining all the required
803 Intel ingredients for this driver, check:
804 <http://www.urbanmyth.org/microcode/>.
807 bool "AMD microcode patch loading support"
811 If you select this option, microcode patch loading support for AMD
812 processors will be enabled.
814 config MICROCODE_OLD_INTERFACE
819 tristate "/dev/cpu/*/msr - Model-specific register support"
821 This device gives privileged processes access to the x86
822 Model-Specific Registers (MSRs). It is a character device with
823 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
824 MSR accesses are directed to a specific CPU on multi-processor
828 tristate "/dev/cpu/*/cpuid - CPU information support"
830 This device gives processes access to the x86 CPUID instruction to
831 be executed on a specific processor. It is a character device
832 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
836 prompt "High Memory Support"
837 default HIGHMEM4G if !X86_NUMAQ
838 default HIGHMEM64G if X86_NUMAQ
843 depends on !X86_NUMAQ
845 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
846 However, the address space of 32-bit x86 processors is only 4
847 Gigabytes large. That means that, if you have a large amount of
848 physical memory, not all of it can be "permanently mapped" by the
849 kernel. The physical memory that's not permanently mapped is called
852 If you are compiling a kernel which will never run on a machine with
853 more than 1 Gigabyte total physical RAM, answer "off" here (default
854 choice and suitable for most users). This will result in a "3GB/1GB"
855 split: 3GB are mapped so that each process sees a 3GB virtual memory
856 space and the remaining part of the 4GB virtual memory space is used
857 by the kernel to permanently map as much physical memory as
860 If the machine has between 1 and 4 Gigabytes physical RAM, then
863 If more than 4 Gigabytes is used then answer "64GB" here. This
864 selection turns Intel PAE (Physical Address Extension) mode on.
865 PAE implements 3-level paging on IA32 processors. PAE is fully
866 supported by Linux, PAE mode is implemented on all recent Intel
867 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
868 then the kernel will not boot on CPUs that don't support PAE!
870 The actual amount of total physical memory will either be
871 auto detected or can be forced by using a kernel command line option
872 such as "mem=256M". (Try "man bootparam" or see the documentation of
873 your boot loader (lilo or loadlin) about how to pass options to the
874 kernel at boot time.)
876 If unsure, say "off".
880 depends on !X86_NUMAQ
882 Select this if you have a 32-bit processor and between 1 and 4
883 gigabytes of physical RAM.
887 depends on !M386 && !M486
890 Select this if you have a 32-bit processor and more than 4
891 gigabytes of physical RAM.
896 depends on EXPERIMENTAL
897 prompt "Memory split" if EMBEDDED
901 Select the desired split between kernel and user memory.
903 If the address range available to the kernel is less than the
904 physical memory installed, the remaining memory will be available
905 as "high memory". Accessing high memory is a little more costly
906 than low memory, as it needs to be mapped into the kernel first.
907 Note that increasing the kernel address space limits the range
908 available to user programs, making the address space there
909 tighter. Selecting anything other than the default 3G/1G split
910 will also likely make your kernel incompatible with binary-only
913 If you are not absolutely sure what you are doing, leave this
917 bool "3G/1G user/kernel split"
918 config VMSPLIT_3G_OPT
920 bool "3G/1G user/kernel split (for full 1G low memory)"
922 bool "2G/2G user/kernel split"
923 config VMSPLIT_2G_OPT
925 bool "2G/2G user/kernel split (for full 2G low memory)"
927 bool "1G/3G user/kernel split"
932 default 0xB0000000 if VMSPLIT_3G_OPT
933 default 0x80000000 if VMSPLIT_2G
934 default 0x78000000 if VMSPLIT_2G_OPT
935 default 0x40000000 if VMSPLIT_1G
941 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
944 bool "PAE (Physical Address Extension) Support"
945 depends on X86_32 && !HIGHMEM4G
947 PAE is required for NX support, and furthermore enables
948 larger swapspace support for non-overcommit purposes. It
949 has the cost of more pagetable lookup overhead, and also
950 consumes more pagetable space per process.
952 config ARCH_PHYS_ADDR_T_64BIT
953 def_bool X86_64 || X86_PAE
955 # Common NUMA Features
957 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
959 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
961 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
963 Enable NUMA (Non Uniform Memory Access) support.
964 The kernel will try to allocate memory used by a CPU on the
965 local memory controller of the CPU and add some more
966 NUMA awareness to the kernel.
968 For 32-bit this is currently highly experimental and should be only
969 used for kernel development. It might also cause boot failures.
970 For 64-bit this is recommended on all multiprocessor Opteron systems.
971 If the system is EM64T, you should say N unless your system is
974 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
975 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
979 prompt "Old style AMD Opteron NUMA detection"
980 depends on X86_64 && NUMA && PCI
982 Enable K8 NUMA node topology detection. You should say Y here if
983 you have a multi processor AMD K8 system. This uses an old
984 method to read the NUMA configuration directly from the builtin
985 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
986 instead, which also takes priority if both are compiled in.
988 config X86_64_ACPI_NUMA
990 prompt "ACPI NUMA detection"
991 depends on X86_64 && NUMA && ACPI && PCI
994 Enable ACPI SRAT based node topology detection.
996 # Some NUMA nodes have memory ranges that span
997 # other nodes. Even though a pfn is valid and
998 # between a node's start and end pfns, it may not
999 # reside on that node. See memmap_init_zone()
1001 config NODES_SPAN_OTHER_NODES
1003 depends on X86_64_ACPI_NUMA
1006 bool "NUMA emulation"
1007 depends on X86_64 && NUMA
1009 Enable NUMA emulation. A flat machine will be split
1010 into virtual nodes when booted with "numa=fake=N", where N is the
1011 number of nodes. This is only useful for debugging.
1014 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1016 default "9" if MAXSMP
1017 default "6" if X86_64
1018 default "4" if X86_NUMAQ
1020 depends on NEED_MULTIPLE_NODES
1022 Specify the maximum number of NUMA Nodes available on the target
1023 system. Increases memory reserved to accomodate various tables.
1025 config HAVE_ARCH_BOOTMEM_NODE
1027 depends on X86_32 && NUMA
1029 config ARCH_HAVE_MEMORY_PRESENT
1031 depends on X86_32 && DISCONTIGMEM
1033 config NEED_NODE_MEMMAP_SIZE
1035 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1037 config HAVE_ARCH_ALLOC_REMAP
1039 depends on X86_32 && NUMA
1041 config ARCH_FLATMEM_ENABLE
1043 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1045 config ARCH_DISCONTIGMEM_ENABLE
1047 depends on NUMA && X86_32
1049 config ARCH_DISCONTIGMEM_DEFAULT
1051 depends on NUMA && X86_32
1053 config ARCH_SPARSEMEM_DEFAULT
1057 config ARCH_SPARSEMEM_ENABLE
1059 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1060 select SPARSEMEM_STATIC if X86_32
1061 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1063 config ARCH_SELECT_MEMORY_MODEL
1065 depends on ARCH_SPARSEMEM_ENABLE
1067 config ARCH_MEMORY_PROBE
1069 depends on MEMORY_HOTPLUG
1074 bool "Allocate 3rd-level pagetables from highmem"
1075 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1077 The VM uses one page table entry for each page of physical memory.
1078 For systems with a lot of RAM, this can be wasteful of precious
1079 low memory. Setting this option will put user-space page table
1080 entries in high memory.
1082 config X86_CHECK_BIOS_CORRUPTION
1083 bool "Check for low memory corruption"
1085 Periodically check for memory corruption in low memory, which
1086 is suspected to be caused by BIOS. Even when enabled in the
1087 configuration, it is disabled at runtime. Enable it by
1088 setting "memory_corruption_check=1" on the kernel command
1089 line. By default it scans the low 64k of memory every 60
1090 seconds; see the memory_corruption_check_size and
1091 memory_corruption_check_period parameters in
1092 Documentation/kernel-parameters.txt to adjust this.
1094 When enabled with the default parameters, this option has
1095 almost no overhead, as it reserves a relatively small amount
1096 of memory and scans it infrequently. It both detects corruption
1097 and prevents it from affecting the running system.
1099 It is, however, intended as a diagnostic tool; if repeatable
1100 BIOS-originated corruption always affects the same memory,
1101 you can use memmap= to prevent the kernel from using that
1104 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1105 bool "Set the default setting of memory_corruption_check"
1106 depends on X86_CHECK_BIOS_CORRUPTION
1109 Set whether the default state of memory_corruption_check is
1112 config X86_RESERVE_LOW_64K
1113 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1116 Reserve the first 64K of physical RAM on BIOSes that are known
1117 to potentially corrupt that memory range. A numbers of BIOSes are
1118 known to utilize this area during suspend/resume, so it must not
1119 be used by the kernel.
1121 Set this to N if you are absolutely sure that you trust the BIOS
1122 to get all its memory reservations and usages right.
1124 If you have doubts about the BIOS (e.g. suspend/resume does not
1125 work or there's kernel crashes after certain hardware hotplug
1126 events) and it's not AMI or Phoenix, then you might want to enable
1127 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1128 corruption patterns.
1132 config MATH_EMULATION
1134 prompt "Math emulation" if X86_32
1136 Linux can emulate a math coprocessor (used for floating point
1137 operations) if you don't have one. 486DX and Pentium processors have
1138 a math coprocessor built in, 486SX and 386 do not, unless you added
1139 a 487DX or 387, respectively. (The messages during boot time can
1140 give you some hints here ["man dmesg"].) Everyone needs either a
1141 coprocessor or this emulation.
1143 If you don't have a math coprocessor, you need to say Y here; if you
1144 say Y here even though you have a coprocessor, the coprocessor will
1145 be used nevertheless. (This behavior can be changed with the kernel
1146 command line option "no387", which comes handy if your coprocessor
1147 is broken. Try "man bootparam" or see the documentation of your boot
1148 loader (lilo or loadlin) about how to pass options to the kernel at
1149 boot time.) This means that it is a good idea to say Y here if you
1150 intend to use this kernel on different machines.
1152 More information about the internals of the Linux math coprocessor
1153 emulation can be found in <file:arch/x86/math-emu/README>.
1155 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1156 kernel, it won't hurt.
1159 bool "MTRR (Memory Type Range Register) support"
1161 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1162 the Memory Type Range Registers (MTRRs) may be used to control
1163 processor access to memory ranges. This is most useful if you have
1164 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1165 allows bus write transfers to be combined into a larger transfer
1166 before bursting over the PCI/AGP bus. This can increase performance
1167 of image write operations 2.5 times or more. Saying Y here creates a
1168 /proc/mtrr file which may be used to manipulate your processor's
1169 MTRRs. Typically the X server should use this.
1171 This code has a reasonably generic interface so that similar
1172 control registers on other processors can be easily supported
1175 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1176 Registers (ARRs) which provide a similar functionality to MTRRs. For
1177 these, the ARRs are used to emulate the MTRRs.
1178 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1179 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1180 write-combining. All of these processors are supported by this code
1181 and it makes sense to say Y here if you have one of them.
1183 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1184 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1185 can lead to all sorts of problems, so it's good to say Y here.
1187 You can safely say Y even if your machine doesn't have MTRRs, you'll
1188 just add about 9 KB to your kernel.
1190 See <file:Documentation/x86/mtrr.txt> for more information.
1192 config MTRR_SANITIZER
1194 prompt "MTRR cleanup support"
1197 Convert MTRR layout from continuous to discrete, so X drivers can
1198 add writeback entries.
1200 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1201 The largest mtrr entry size for a continous block can be set with
1206 config MTRR_SANITIZER_ENABLE_DEFAULT
1207 int "MTRR cleanup enable value (0-1)"
1210 depends on MTRR_SANITIZER
1212 Enable mtrr cleanup default value
1214 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1215 int "MTRR cleanup spare reg num (0-7)"
1218 depends on MTRR_SANITIZER
1220 mtrr cleanup spare entries default, it can be changed via
1221 mtrr_spare_reg_nr=N on the kernel command line.
1225 prompt "x86 PAT support"
1228 Use PAT attributes to setup page level cache control.
1230 PATs are the modern equivalents of MTRRs and are much more
1231 flexible than MTRRs.
1233 Say N here if you see bootup problems (boot crash, boot hang,
1234 spontaneous reboots) or a non-working video driver.
1239 bool "EFI runtime service support"
1242 This enables the kernel to use EFI runtime services that are
1243 available (such as the EFI variable services).
1245 This option is only useful on systems that have EFI firmware.
1246 In addition, you should use the latest ELILO loader available
1247 at <http://elilo.sourceforge.net> in order to take advantage
1248 of EFI runtime services. However, even with this option, the
1249 resultant kernel should continue to boot on existing non-EFI
1254 prompt "Enable seccomp to safely compute untrusted bytecode"
1256 This kernel feature is useful for number crunching applications
1257 that may need to compute untrusted bytecode during their
1258 execution. By using pipes or other transports made available to
1259 the process as file descriptors supporting the read/write
1260 syscalls, it's possible to isolate those applications in
1261 their own address space using seccomp. Once seccomp is
1262 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1263 and the task is only allowed to execute a few safe syscalls
1264 defined by each seccomp mode.
1266 If unsure, say Y. Only embedded should say N here.
1268 config CC_STACKPROTECTOR
1269 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1270 depends on X86_64 && EXPERIMENTAL && BROKEN
1272 This option turns on the -fstack-protector GCC feature. This
1273 feature puts, at the beginning of critical functions, a canary
1274 value on the stack just before the return address, and validates
1275 the value just before actually returning. Stack based buffer
1276 overflows (that need to overwrite this return address) now also
1277 overwrite the canary, which gets detected and the attack is then
1278 neutralized via a kernel panic.
1280 This feature requires gcc version 4.2 or above, or a distribution
1281 gcc with the feature backported. Older versions are automatically
1282 detected and for those versions, this configuration option is ignored.
1284 config CC_STACKPROTECTOR_ALL
1285 bool "Use stack-protector for all functions"
1286 depends on CC_STACKPROTECTOR
1288 Normally, GCC only inserts the canary value protection for
1289 functions that use large-ish on-stack buffers. By enabling
1290 this option, GCC will be asked to do this for ALL functions.
1292 source kernel/Kconfig.hz
1295 bool "kexec system call"
1296 depends on X86_BIOS_REBOOT
1298 kexec is a system call that implements the ability to shutdown your
1299 current kernel, and to start another kernel. It is like a reboot
1300 but it is independent of the system firmware. And like a reboot
1301 you can start any kernel with it, not just Linux.
1303 The name comes from the similarity to the exec system call.
1305 It is an ongoing process to be certain the hardware in a machine
1306 is properly shutdown, so do not be surprised if this code does not
1307 initially work for you. It may help to enable device hotplugging
1308 support. As of this writing the exact hardware interface is
1309 strongly in flux, so no good recommendation can be made.
1312 bool "kernel crash dumps"
1313 depends on X86_64 || (X86_32 && HIGHMEM)
1315 Generate crash dump after being started by kexec.
1316 This should be normally only set in special crash dump kernels
1317 which are loaded in the main kernel with kexec-tools into
1318 a specially reserved region and then later executed after
1319 a crash by kdump/kexec. The crash dump kernel must be compiled
1320 to a memory address not used by the main kernel or BIOS using
1321 PHYSICAL_START, or it must be built as a relocatable image
1322 (CONFIG_RELOCATABLE=y).
1323 For more details see Documentation/kdump/kdump.txt
1326 bool "kexec jump (EXPERIMENTAL)"
1327 depends on EXPERIMENTAL
1328 depends on KEXEC && HIBERNATION && X86_32
1330 Jump between original kernel and kexeced kernel and invoke
1331 code in physical address mode via KEXEC
1333 config PHYSICAL_START
1334 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1335 default "0x1000000" if X86_NUMAQ
1336 default "0x200000" if X86_64
1339 This gives the physical address where the kernel is loaded.
1341 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1342 bzImage will decompress itself to above physical address and
1343 run from there. Otherwise, bzImage will run from the address where
1344 it has been loaded by the boot loader and will ignore above physical
1347 In normal kdump cases one does not have to set/change this option
1348 as now bzImage can be compiled as a completely relocatable image
1349 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1350 address. This option is mainly useful for the folks who don't want
1351 to use a bzImage for capturing the crash dump and want to use a
1352 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1353 to be specifically compiled to run from a specific memory area
1354 (normally a reserved region) and this option comes handy.
1356 So if you are using bzImage for capturing the crash dump, leave
1357 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1358 Otherwise if you plan to use vmlinux for capturing the crash dump
1359 change this value to start of the reserved region (Typically 16MB
1360 0x1000000). In other words, it can be set based on the "X" value as
1361 specified in the "crashkernel=YM@XM" command line boot parameter
1362 passed to the panic-ed kernel. Typically this parameter is set as
1363 crashkernel=64M@16M. Please take a look at
1364 Documentation/kdump/kdump.txt for more details about crash dumps.
1366 Usage of bzImage for capturing the crash dump is recommended as
1367 one does not have to build two kernels. Same kernel can be used
1368 as production kernel and capture kernel. Above option should have
1369 gone away after relocatable bzImage support is introduced. But it
1370 is present because there are users out there who continue to use
1371 vmlinux for dump capture. This option should go away down the
1374 Don't change this unless you know what you are doing.
1377 bool "Build a relocatable kernel (EXPERIMENTAL)"
1378 depends on EXPERIMENTAL
1380 This builds a kernel image that retains relocation information
1381 so it can be loaded someplace besides the default 1MB.
1382 The relocations tend to make the kernel binary about 10% larger,
1383 but are discarded at runtime.
1385 One use is for the kexec on panic case where the recovery kernel
1386 must live at a different physical address than the primary
1389 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1390 it has been loaded at and the compile time physical address
1391 (CONFIG_PHYSICAL_START) is ignored.
1393 config PHYSICAL_ALIGN
1395 prompt "Alignment value to which kernel should be aligned" if X86_32
1396 default "0x100000" if X86_32
1397 default "0x200000" if X86_64
1398 range 0x2000 0x400000
1400 This value puts the alignment restrictions on physical address
1401 where kernel is loaded and run from. Kernel is compiled for an
1402 address which meets above alignment restriction.
1404 If bootloader loads the kernel at a non-aligned address and
1405 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1406 address aligned to above value and run from there.
1408 If bootloader loads the kernel at a non-aligned address and
1409 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1410 load address and decompress itself to the address it has been
1411 compiled for and run from there. The address for which kernel is
1412 compiled already meets above alignment restrictions. Hence the
1413 end result is that kernel runs from a physical address meeting
1414 above alignment restrictions.
1416 Don't change this unless you know what you are doing.
1419 bool "Support for hot-pluggable CPUs"
1420 depends on SMP && HOTPLUG && !X86_VOYAGER
1422 Say Y here to allow turning CPUs off and on. CPUs can be
1423 controlled through /sys/devices/system/cpu.
1424 ( Note: power management support will enable this option
1425 automatically on SMP systems. )
1426 Say N if you want to disable CPU hotplug.
1430 prompt "Compat VDSO support"
1431 depends on X86_32 || IA32_EMULATION
1433 Map the 32-bit VDSO to the predictable old-style address too.
1435 Say N here if you are running a sufficiently recent glibc
1436 version (2.3.3 or later), to remove the high-mapped
1437 VDSO mapping and to exclusively use the randomized VDSO.
1442 bool "Built-in kernel command line"
1445 Allow for specifying boot arguments to the kernel at
1446 build time. On some systems (e.g. embedded ones), it is
1447 necessary or convenient to provide some or all of the
1448 kernel boot arguments with the kernel itself (that is,
1449 to not rely on the boot loader to provide them.)
1451 To compile command line arguments into the kernel,
1452 set this option to 'Y', then fill in the
1453 the boot arguments in CONFIG_CMDLINE.
1455 Systems with fully functional boot loaders (i.e. non-embedded)
1456 should leave this option set to 'N'.
1459 string "Built-in kernel command string"
1460 depends on CMDLINE_BOOL
1463 Enter arguments here that should be compiled into the kernel
1464 image and used at boot time. If the boot loader provides a
1465 command line at boot time, it is appended to this string to
1466 form the full kernel command line, when the system boots.
1468 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1469 change this behavior.
1471 In most cases, the command line (whether built-in or provided
1472 by the boot loader) should specify the device for the root
1475 config CMDLINE_OVERRIDE
1476 bool "Built-in command line overrides boot loader arguments"
1478 depends on CMDLINE_BOOL
1480 Set this option to 'Y' to have the kernel ignore the boot loader
1481 command line, and use ONLY the built-in command line.
1483 This is used to work around broken boot loaders. This should
1484 be set to 'N' under normal conditions.
1488 config ARCH_ENABLE_MEMORY_HOTPLUG
1490 depends on X86_64 || (X86_32 && HIGHMEM)
1492 config HAVE_ARCH_EARLY_PFN_TO_NID
1496 menu "Power management and ACPI options"
1497 depends on !X86_VOYAGER
1499 config ARCH_HIBERNATION_HEADER
1501 depends on X86_64 && HIBERNATION
1503 source "kernel/power/Kconfig"
1505 source "drivers/acpi/Kconfig"
1510 depends on APM || APM_MODULE
1513 tristate "APM (Advanced Power Management) BIOS support"
1514 depends on X86_32 && PM_SLEEP
1516 APM is a BIOS specification for saving power using several different
1517 techniques. This is mostly useful for battery powered laptops with
1518 APM compliant BIOSes. If you say Y here, the system time will be
1519 reset after a RESUME operation, the /proc/apm device will provide
1520 battery status information, and user-space programs will receive
1521 notification of APM "events" (e.g. battery status change).
1523 If you select "Y" here, you can disable actual use of the APM
1524 BIOS by passing the "apm=off" option to the kernel at boot time.
1526 Note that the APM support is almost completely disabled for
1527 machines with more than one CPU.
1529 In order to use APM, you will need supporting software. For location
1530 and more information, read <file:Documentation/power/pm.txt> and the
1531 Battery Powered Linux mini-HOWTO, available from
1532 <http://www.tldp.org/docs.html#howto>.
1534 This driver does not spin down disk drives (see the hdparm(8)
1535 manpage ("man 8 hdparm") for that), and it doesn't turn off
1536 VESA-compliant "green" monitors.
1538 This driver does not support the TI 4000M TravelMate and the ACER
1539 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1540 desktop machines also don't have compliant BIOSes, and this driver
1541 may cause those machines to panic during the boot phase.
1543 Generally, if you don't have a battery in your machine, there isn't
1544 much point in using this driver and you should say N. If you get
1545 random kernel OOPSes or reboots that don't seem to be related to
1546 anything, try disabling/enabling this option (or disabling/enabling
1549 Some other things you should try when experiencing seemingly random,
1552 1) make sure that you have enough swap space and that it is
1554 2) pass the "no-hlt" option to the kernel
1555 3) switch on floating point emulation in the kernel and pass
1556 the "no387" option to the kernel
1557 4) pass the "floppy=nodma" option to the kernel
1558 5) pass the "mem=4M" option to the kernel (thereby disabling
1559 all but the first 4 MB of RAM)
1560 6) make sure that the CPU is not over clocked.
1561 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1562 8) disable the cache from your BIOS settings
1563 9) install a fan for the video card or exchange video RAM
1564 10) install a better fan for the CPU
1565 11) exchange RAM chips
1566 12) exchange the motherboard.
1568 To compile this driver as a module, choose M here: the
1569 module will be called apm.
1573 config APM_IGNORE_USER_SUSPEND
1574 bool "Ignore USER SUSPEND"
1576 This option will ignore USER SUSPEND requests. On machines with a
1577 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1578 series notebooks, it is necessary to say Y because of a BIOS bug.
1580 config APM_DO_ENABLE
1581 bool "Enable PM at boot time"
1583 Enable APM features at boot time. From page 36 of the APM BIOS
1584 specification: "When disabled, the APM BIOS does not automatically
1585 power manage devices, enter the Standby State, enter the Suspend
1586 State, or take power saving steps in response to CPU Idle calls."
1587 This driver will make CPU Idle calls when Linux is idle (unless this
1588 feature is turned off -- see "Do CPU IDLE calls", below). This
1589 should always save battery power, but more complicated APM features
1590 will be dependent on your BIOS implementation. You may need to turn
1591 this option off if your computer hangs at boot time when using APM
1592 support, or if it beeps continuously instead of suspending. Turn
1593 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1594 T400CDT. This is off by default since most machines do fine without
1598 bool "Make CPU Idle calls when idle"
1600 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1601 On some machines, this can activate improved power savings, such as
1602 a slowed CPU clock rate, when the machine is idle. These idle calls
1603 are made after the idle loop has run for some length of time (e.g.,
1604 333 mS). On some machines, this will cause a hang at boot time or
1605 whenever the CPU becomes idle. (On machines with more than one CPU,
1606 this option does nothing.)
1608 config APM_DISPLAY_BLANK
1609 bool "Enable console blanking using APM"
1611 Enable console blanking using the APM. Some laptops can use this to
1612 turn off the LCD backlight when the screen blanker of the Linux
1613 virtual console blanks the screen. Note that this is only used by
1614 the virtual console screen blanker, and won't turn off the backlight
1615 when using the X Window system. This also doesn't have anything to
1616 do with your VESA-compliant power-saving monitor. Further, this
1617 option doesn't work for all laptops -- it might not turn off your
1618 backlight at all, or it might print a lot of errors to the console,
1619 especially if you are using gpm.
1621 config APM_ALLOW_INTS
1622 bool "Allow interrupts during APM BIOS calls"
1624 Normally we disable external interrupts while we are making calls to
1625 the APM BIOS as a measure to lessen the effects of a badly behaving
1626 BIOS implementation. The BIOS should reenable interrupts if it
1627 needs to. Unfortunately, some BIOSes do not -- especially those in
1628 many of the newer IBM Thinkpads. If you experience hangs when you
1629 suspend, try setting this to Y. Otherwise, say N.
1631 config APM_REAL_MODE_POWER_OFF
1632 bool "Use real mode APM BIOS call to power off"
1634 Use real mode APM BIOS calls to switch off the computer. This is
1635 a work-around for a number of buggy BIOSes. Switch this option on if
1636 your computer crashes instead of powering off properly.
1640 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1642 source "drivers/cpuidle/Kconfig"
1644 source "drivers/idle/Kconfig"
1649 menu "Bus options (PCI etc.)"
1654 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1656 Find out whether you have a PCI motherboard. PCI is the name of a
1657 bus system, i.e. the way the CPU talks to the other stuff inside
1658 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1659 VESA. If you have PCI, say Y, otherwise N.
1662 prompt "PCI access mode"
1663 depends on X86_32 && PCI
1666 On PCI systems, the BIOS can be used to detect the PCI devices and
1667 determine their configuration. However, some old PCI motherboards
1668 have BIOS bugs and may crash if this is done. Also, some embedded
1669 PCI-based systems don't have any BIOS at all. Linux can also try to
1670 detect the PCI hardware directly without using the BIOS.
1672 With this option, you can specify how Linux should detect the
1673 PCI devices. If you choose "BIOS", the BIOS will be used,
1674 if you choose "Direct", the BIOS won't be used, and if you
1675 choose "MMConfig", then PCI Express MMCONFIG will be used.
1676 If you choose "Any", the kernel will try MMCONFIG, then the
1677 direct access method and falls back to the BIOS if that doesn't
1678 work. If unsure, go with the default, which is "Any".
1683 config PCI_GOMMCONFIG
1700 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1702 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1705 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1709 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1713 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1720 bool "Support mmconfig PCI config space access"
1721 depends on X86_64 && PCI && ACPI
1724 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1725 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1727 DMA remapping (DMAR) devices support enables independent address
1728 translations for Direct Memory Access (DMA) from devices.
1729 These DMA remapping devices are reported via ACPI tables
1730 and include PCI device scope covered by these DMA
1735 prompt "Support for Graphics workaround"
1738 Current Graphics drivers tend to use physical address
1739 for DMA and avoid using DMA APIs. Setting this config
1740 option permits the IOMMU driver to set a unity map for
1741 all the OS-visible memory. Hence the driver can continue
1742 to use physical addresses for DMA.
1744 config DMAR_FLOPPY_WA
1748 Floppy disk drivers are know to bypass DMA API calls
1749 thereby failing to work when IOMMU is enabled. This
1750 workaround will setup a 1:1 mapping for the first
1751 16M to make floppy (an ISA device) work.
1754 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1755 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1757 Supports Interrupt remapping for IO-APIC and MSI devices.
1758 To use x2apic mode in the CPU's which support x2APIC enhancements or
1759 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1761 source "drivers/pci/pcie/Kconfig"
1763 source "drivers/pci/Kconfig"
1765 # x86_64 have no ISA slots, but do have ISA-style DMA.
1773 depends on !X86_VOYAGER
1775 Find out whether you have ISA slots on your motherboard. ISA is the
1776 name of a bus system, i.e. the way the CPU talks to the other stuff
1777 inside your box. Other bus systems are PCI, EISA, MicroChannel
1778 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1779 newer boards don't support it. If you have ISA, say Y, otherwise N.
1785 The Extended Industry Standard Architecture (EISA) bus was
1786 developed as an open alternative to the IBM MicroChannel bus.
1788 The EISA bus provided some of the features of the IBM MicroChannel
1789 bus while maintaining backward compatibility with cards made for
1790 the older ISA bus. The EISA bus saw limited use between 1988 and
1791 1995 when it was made obsolete by the PCI bus.
1793 Say Y here if you are building a kernel for an EISA-based machine.
1797 source "drivers/eisa/Kconfig"
1800 bool "MCA support" if !X86_VOYAGER
1801 default y if X86_VOYAGER
1803 MicroChannel Architecture is found in some IBM PS/2 machines and
1804 laptops. It is a bus system similar to PCI or ISA. See
1805 <file:Documentation/mca.txt> (and especially the web page given
1806 there) before attempting to build an MCA bus kernel.
1808 source "drivers/mca/Kconfig"
1811 tristate "NatSemi SCx200 support"
1812 depends on !X86_VOYAGER
1814 This provides basic support for National Semiconductor's
1815 (now AMD's) Geode processors. The driver probes for the
1816 PCI-IDs of several on-chip devices, so its a good dependency
1817 for other scx200_* drivers.
1819 If compiled as a module, the driver is named scx200.
1821 config SCx200HR_TIMER
1822 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1823 depends on SCx200 && GENERIC_TIME
1826 This driver provides a clocksource built upon the on-chip
1827 27MHz high-resolution timer. Its also a workaround for
1828 NSC Geode SC-1100's buggy TSC, which loses time when the
1829 processor goes idle (as is done by the scheduler). The
1830 other workaround is idle=poll boot option.
1832 config GEODE_MFGPT_TIMER
1834 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1835 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1837 This driver provides a clock event source based on the MFGPT
1838 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1839 MFGPTs have a better resolution and max interval than the
1840 generic PIT, and are suitable for use as high-res timers.
1843 bool "One Laptop Per Child support"
1846 Add support for detecting the unique features of the OLPC
1853 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1855 source "drivers/pcmcia/Kconfig"
1857 source "drivers/pci/hotplug/Kconfig"
1862 menu "Executable file formats / Emulations"
1864 source "fs/Kconfig.binfmt"
1866 config IA32_EMULATION
1867 bool "IA32 Emulation"
1869 select COMPAT_BINFMT_ELF
1871 Include code to run 32-bit programs under a 64-bit kernel. You should
1872 likely turn this on, unless you're 100% sure that you don't have any
1873 32-bit programs left.
1876 tristate "IA32 a.out support"
1877 depends on IA32_EMULATION
1879 Support old a.out binaries in the 32bit emulation.
1883 depends on IA32_EMULATION
1885 config COMPAT_FOR_U64_ALIGNMENT
1889 config SYSVIPC_COMPAT
1891 depends on COMPAT && SYSVIPC
1896 config HAVE_ATOMIC_IOMAP
1900 source "net/Kconfig"
1902 source "drivers/Kconfig"
1904 source "drivers/firmware/Kconfig"
1908 source "arch/x86/Kconfig.debug"
1910 source "security/Kconfig"
1912 source "crypto/Kconfig"
1914 source "arch/x86/kvm/Kconfig"
1916 source "lib/Kconfig"
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