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
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select HAVE_KRETPROBES
31 select HAVE_FTRACE_MCOUNT_RECORD
32 select HAVE_DYNAMIC_FTRACE
33 select HAVE_FUNCTION_TRACER
34 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
35 select HAVE_ARCH_KGDB if !X86_VOYAGER
36 select HAVE_ARCH_TRACEHOOK
37 select HAVE_GENERIC_DMA_COHERENT if X86_32
38 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 default "arch/x86/configs/i386_defconfig" if X86_32
43 default "arch/x86/configs/x86_64_defconfig" if X86_64
48 config GENERIC_CMOS_UPDATE
51 config CLOCKSOURCE_WATCHDOG
54 config GENERIC_CLOCKEVENTS
57 config GENERIC_CLOCKEVENTS_BROADCAST
59 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
61 config LOCKDEP_SUPPORT
64 config STACKTRACE_SUPPORT
67 config HAVE_LATENCYTOP_SUPPORT
70 config FAST_CMPXCHG_LOCAL
83 config GENERIC_ISA_DMA
93 config GENERIC_HWEIGHT
99 config ARCH_MAY_HAVE_PC_FDC
102 config RWSEM_GENERIC_SPINLOCK
105 config RWSEM_XCHGADD_ALGORITHM
108 config ARCH_HAS_CPU_IDLE_WAIT
111 config GENERIC_CALIBRATE_DELAY
114 config GENERIC_TIME_VSYSCALL
118 config ARCH_HAS_CPU_RELAX
121 config ARCH_HAS_DEFAULT_IDLE
124 config ARCH_HAS_CACHE_LINE_SIZE
127 config HAVE_SETUP_PER_CPU_AREA
128 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
130 config HAVE_CPUMASK_OF_CPU_MAP
133 config ARCH_HIBERNATION_POSSIBLE
135 depends on !SMP || !X86_VOYAGER
137 config ARCH_SUSPEND_POSSIBLE
139 depends on !X86_VOYAGER
145 config ARCH_POPULATES_NODE_MAP
152 config ARCH_SUPPORTS_OPTIMIZED_INLINING
155 # Use the generic interrupt handling code in kernel/irq/:
156 config GENERIC_HARDIRQS
160 config GENERIC_IRQ_PROBE
164 config GENERIC_PENDING_IRQ
166 depends on GENERIC_HARDIRQS && SMP
171 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
174 config USE_GENERIC_SMP_HELPERS
180 depends on X86_32 && SMP
184 depends on X86_64 && SMP
189 depends on (X86_32 && !X86_VOYAGER) || X86_64
192 config X86_BIOS_REBOOT
194 depends on !X86_VOYAGER
197 config X86_TRAMPOLINE
199 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
204 source "init/Kconfig"
205 source "kernel/Kconfig.freezer"
207 menu "Processor type and features"
209 source "kernel/time/Kconfig"
212 bool "Symmetric multi-processing support"
214 This enables support for systems with more than one CPU. If you have
215 a system with only one CPU, like most personal computers, say N. If
216 you have a system with more than one CPU, say Y.
218 If you say N here, the kernel will run on single and multiprocessor
219 machines, but will use only one CPU of a multiprocessor machine. If
220 you say Y here, the kernel will run on many, but not all,
221 singleprocessor machines. On a singleprocessor machine, the kernel
222 will run faster if you say N here.
224 Note that if you say Y here and choose architecture "586" or
225 "Pentium" under "Processor family", the kernel will not work on 486
226 architectures. Similarly, multiprocessor kernels for the "PPro"
227 architecture may not work on all Pentium based boards.
229 People using multiprocessor machines who say Y here should also say
230 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
231 Management" code will be disabled if you say Y here.
233 See also <file:Documentation/i386/IO-APIC.txt>,
234 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
235 <http://www.tldp.org/docs.html#howto>.
237 If you don't know what to do here, say N.
239 config X86_HAS_BOOT_CPU_ID
241 depends on X86_VOYAGER
243 config X86_FIND_SMP_CONFIG
245 depends on X86_MPPARSE || X86_VOYAGER
250 bool "Enable MPS table"
251 depends on X86_LOCAL_APIC
253 For old smp systems that do not have proper acpi support. Newer systems
254 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
260 depends on X86_LOCAL_APIC
264 prompt "Subarchitecture Type"
270 Choose this option if your computer is a standard PC or compatible.
276 Select this for an AMD Elan processor.
278 Do not use this option for K6/Athlon/Opteron processors!
280 If unsure, choose "PC-compatible" instead.
284 depends on X86_32 && (SMP || BROKEN) && !PCI
286 Voyager is an MCA-based 32-way capable SMP architecture proprietary
287 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
291 If you do not specifically know you have a Voyager based machine,
292 say N here, otherwise the kernel you build will not be bootable.
294 config X86_GENERICARCH
295 bool "Generic architecture"
298 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
299 subarchitectures. It is intended for a generic binary kernel.
300 if you select them all, kernel will probe it one by one. and will
306 bool "NUMAQ (IBM/Sequent)"
307 depends on SMP && X86_32 && PCI && X86_MPPARSE
310 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
311 NUMA multiquad box. This changes the way that processors are
312 bootstrapped, and uses Clustered Logical APIC addressing mode instead
313 of Flat Logical. You will need a new lynxer.elf file to flash your
314 firmware with - send email to <Martin.Bligh@us.ibm.com>.
317 bool "Summit/EXA (IBM x440)"
318 depends on X86_32 && SMP
320 This option is needed for IBM systems that use the Summit/EXA chipset.
321 In particular, it is needed for the x440.
324 bool "Support for Unisys ES7000 IA32 series"
325 depends on X86_32 && SMP
327 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
328 supposed to run on an IA32-based Unisys ES7000 system.
331 bool "Support for big SMP systems with more than 8 CPUs"
332 depends on X86_32 && SMP
334 This option is needed for the systems that have more than 8 CPUs
335 and if the system is not of any sub-arch type above.
340 bool "Support for ScaleMP vSMP"
342 depends on X86_64 && PCI
344 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
345 supposed to run on these EM64T-based machines. Only choose this option
346 if you have one of these machines.
351 bool "SGI 320/540 (Visual Workstation)"
352 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
354 The SGI Visual Workstation series is an IA32-based workstation
355 based on SGI systems chips with some legacy PC hardware attached.
357 Say Y here to create a kernel to run on the SGI 320 or 540.
359 A kernel compiled for the Visual Workstation will run on general
360 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
363 bool "RDC R-321x SoC"
366 select X86_REBOOTFIXUPS
368 This option is needed for RDC R-321x system-on-chip, also known
370 If you don't have one of these chips, you should say N here.
372 config SCHED_NO_NO_OMIT_FRAME_POINTER
374 prompt "Single-depth WCHAN output"
377 Calculate simpler /proc/<PID>/wchan values. If this option
378 is disabled then wchan values will recurse back to the
379 caller function. This provides more accurate wchan values,
380 at the expense of slightly more scheduling overhead.
382 If in doubt, say "Y".
384 menuconfig PARAVIRT_GUEST
385 bool "Paravirtualized guest support"
387 Say Y here to get to see options related to running Linux under
388 various hypervisors. This option alone does not add any kernel code.
390 If you say N, all options in this submenu will be skipped and disabled.
394 source "arch/x86/xen/Kconfig"
397 bool "VMI Guest support"
400 depends on !X86_VOYAGER
402 VMI provides a paravirtualized interface to the VMware ESX server
403 (it could be used by other hypervisors in theory too, but is not
404 at the moment), by linking the kernel to a GPL-ed ROM module
405 provided by the hypervisor.
408 bool "KVM paravirtualized clock"
410 select PARAVIRT_CLOCK
411 depends on !X86_VOYAGER
413 Turning on this option will allow you to run a paravirtualized clock
414 when running over the KVM hypervisor. Instead of relying on a PIT
415 (or probably other) emulation by the underlying device model, the host
416 provides the guest with timing infrastructure such as time of day, and
420 bool "KVM Guest support"
422 depends on !X86_VOYAGER
424 This option enables various optimizations for running under the KVM
427 source "arch/x86/lguest/Kconfig"
430 bool "Enable paravirtualization code"
431 depends on !X86_VOYAGER
433 This changes the kernel so it can modify itself when it is run
434 under a hypervisor, potentially improving performance significantly
435 over full virtualization. However, when run without a hypervisor
436 the kernel is theoretically slower and slightly larger.
438 config PARAVIRT_CLOCK
444 config PARAVIRT_DEBUG
445 bool "paravirt-ops debugging"
446 depends on PARAVIRT && DEBUG_KERNEL
448 Enable to debug paravirt_ops internals. Specifically, BUG if
449 a paravirt_op is missing when it is called.
454 This option adds a kernel parameter 'memtest', which allows memtest
456 memtest=0, mean disabled; -- default
457 memtest=1, mean do 1 test pattern;
459 memtest=4, mean do 4 test patterns.
460 If you are unsure how to answer this question, answer N.
462 config X86_SUMMIT_NUMA
464 depends on X86_32 && NUMA && X86_GENERICARCH
466 config X86_CYCLONE_TIMER
468 depends on X86_GENERICARCH
470 config ES7000_CLUSTERED_APIC
472 depends on SMP && X86_ES7000 && MPENTIUMIII
474 source "arch/x86/Kconfig.cpu"
478 prompt "HPET Timer Support" if X86_32
480 Use the IA-PC HPET (High Precision Event Timer) to manage
481 time in preference to the PIT and RTC, if a HPET is
483 HPET is the next generation timer replacing legacy 8254s.
484 The HPET provides a stable time base on SMP
485 systems, unlike the TSC, but it is more expensive to access,
486 as it is off-chip. You can find the HPET spec at
487 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
489 You can safely choose Y here. However, HPET will only be
490 activated if the platform and the BIOS support this feature.
491 Otherwise the 8254 will be used for timing services.
493 Choose N to continue using the legacy 8254 timer.
495 config HPET_EMULATE_RTC
497 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
499 # Mark as embedded because too many people got it wrong.
500 # The code disables itself when not needed.
503 bool "Enable DMI scanning" if EMBEDDED
505 Enabled scanning of DMI to identify machine quirks. Say Y
506 here unless you have verified that your setup is not
507 affected by entries in the DMI blacklist. Required by PNP
511 bool "GART IOMMU support" if EMBEDDED
515 depends on X86_64 && PCI
517 Support for full DMA access of devices with 32bit memory access only
518 on systems with more than 3GB. This is usually needed for USB,
519 sound, many IDE/SATA chipsets and some other devices.
520 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
521 based hardware IOMMU and a software bounce buffer based IOMMU used
522 on Intel systems and as fallback.
523 The code is only active when needed (enough memory and limited
524 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
528 bool "IBM Calgary IOMMU support"
530 depends on X86_64 && PCI && EXPERIMENTAL
532 Support for hardware IOMMUs in IBM's xSeries x366 and x460
533 systems. Needed to run systems with more than 3GB of memory
534 properly with 32-bit PCI devices that do not support DAC
535 (Double Address Cycle). Calgary also supports bus level
536 isolation, where all DMAs pass through the IOMMU. This
537 prevents them from going anywhere except their intended
538 destination. This catches hard-to-find kernel bugs and
539 mis-behaving drivers and devices that do not use the DMA-API
540 properly to set up their DMA buffers. The IOMMU can be
541 turned off at boot time with the iommu=off parameter.
542 Normally the kernel will make the right choice by itself.
545 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
547 prompt "Should Calgary be enabled by default?"
548 depends on CALGARY_IOMMU
550 Should Calgary be enabled by default? if you choose 'y', Calgary
551 will be used (if it exists). If you choose 'n', Calgary will not be
552 used even if it exists. If you choose 'n' and would like to use
553 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
557 bool "AMD IOMMU support"
560 depends on X86_64 && PCI && ACPI
562 With this option you can enable support for AMD IOMMU hardware in
563 your system. An IOMMU is a hardware component which provides
564 remapping of DMA memory accesses from devices. With an AMD IOMMU you
565 can isolate the the DMA memory of different devices and protect the
566 system from misbehaving device drivers or hardware.
568 You can find out if your system has an AMD IOMMU if you look into
569 your BIOS for an option to enable it or if you have an IVRS ACPI
572 # need this always selected by IOMMU for the VIA workaround
576 Support for software bounce buffers used on x86-64 systems
577 which don't have a hardware IOMMU (e.g. the current generation
578 of Intel's x86-64 CPUs). Using this PCI devices which can only
579 access 32-bits of memory can be used on systems with more than
580 3 GB of memory. If unsure, say Y.
583 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
586 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
587 depends on X86_64 && SMP && BROKEN
590 Configure maximum number of CPUS and NUMA Nodes for this architecture.
594 int "Maximum number of CPUs (2-512)" if !MAXSMP
597 default "4096" if MAXSMP
598 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
601 This allows you to specify the maximum number of CPUs which this
602 kernel will support. The maximum supported value is 512 and the
603 minimum value which makes sense is 2.
605 This is purely to save memory - each supported CPU adds
606 approximately eight kilobytes to the kernel image.
609 bool "SMT (Hyperthreading) scheduler support"
612 SMT scheduler support improves the CPU scheduler's decision making
613 when dealing with Intel Pentium 4 chips with HyperThreading at a
614 cost of slightly increased overhead in some places. If unsure say
619 prompt "Multi-core scheduler support"
622 Multi-core scheduler support improves the CPU scheduler's decision
623 making when dealing with multi-core CPU chips at a cost of slightly
624 increased overhead in some places. If unsure say N here.
626 source "kernel/Kconfig.preempt"
629 bool "Local APIC support on uniprocessors"
630 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
632 A local APIC (Advanced Programmable Interrupt Controller) is an
633 integrated interrupt controller in the CPU. If you have a single-CPU
634 system which has a processor with a local APIC, you can say Y here to
635 enable and use it. If you say Y here even though your machine doesn't
636 have a local APIC, then the kernel will still run with no slowdown at
637 all. The local APIC supports CPU-generated self-interrupts (timer,
638 performance counters), and the NMI watchdog which detects hard
642 bool "IO-APIC support on uniprocessors"
643 depends on X86_UP_APIC
645 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
646 SMP-capable replacement for PC-style interrupt controllers. Most
647 SMP systems and many recent uniprocessor systems have one.
649 If you have a single-CPU system with an IO-APIC, you can say Y here
650 to use it. If you say Y here even though your machine doesn't have
651 an IO-APIC, then the kernel will still run with no slowdown at all.
653 config X86_LOCAL_APIC
655 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
659 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
661 config X86_VISWS_APIC
663 depends on X86_32 && X86_VISWS
666 bool "Machine Check Exception"
667 depends on !X86_VOYAGER
669 Machine Check Exception support allows the processor to notify the
670 kernel if it detects a problem (e.g. overheating, component failure).
671 The action the kernel takes depends on the severity of the problem,
672 ranging from a warning message on the console, to halting the machine.
673 Your processor must be a Pentium or newer to support this - check the
674 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
675 have a design flaw which leads to false MCE events - hence MCE is
676 disabled on all P5 processors, unless explicitly enabled with "mce"
677 as a boot argument. Similarly, if MCE is built in and creates a
678 problem on some new non-standard machine, you can boot with "nomce"
679 to disable it. MCE support simply ignores non-MCE processors like
680 the 386 and 486, so nearly everyone can say Y here.
684 prompt "Intel MCE features"
685 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
687 Additional support for intel specific MCE features such as
692 prompt "AMD MCE features"
693 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
695 Additional support for AMD specific MCE features such as
696 the DRAM Error Threshold.
698 config X86_MCE_NONFATAL
699 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
700 depends on X86_32 && X86_MCE
702 Enabling this feature starts a timer that triggers every 5 seconds which
703 will look at the machine check registers to see if anything happened.
704 Non-fatal problems automatically get corrected (but still logged).
705 Disable this if you don't want to see these messages.
706 Seeing the messages this option prints out may be indicative of dying
707 or out-of-spec (ie, overclocked) hardware.
708 This option only does something on certain CPUs.
709 (AMD Athlon/Duron and Intel Pentium 4)
711 config X86_MCE_P4THERMAL
712 bool "check for P4 thermal throttling interrupt."
713 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
715 Enabling this feature will cause a message to be printed when the P4
716 enters thermal throttling.
719 bool "Enable VM86 support" if EMBEDDED
723 This option is required by programs like DOSEMU to run 16-bit legacy
724 code on X86 processors. It also may be needed by software like
725 XFree86 to initialize some video cards via BIOS. Disabling this
726 option saves about 6k.
729 tristate "Toshiba Laptop support"
732 This adds a driver to safely access the System Management Mode of
733 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
734 not work on models with a Phoenix BIOS. The System Management Mode
735 is used to set the BIOS and power saving options on Toshiba portables.
737 For information on utilities to make use of this driver see the
738 Toshiba Linux utilities web site at:
739 <http://www.buzzard.org.uk/toshiba/>.
741 Say Y if you intend to run this kernel on a Toshiba portable.
745 tristate "Dell laptop support"
747 This adds a driver to safely access the System Management Mode
748 of the CPU on the Dell Inspiron 8000. The System Management Mode
749 is used to read cpu temperature and cooling fan status and to
750 control the fans on the I8K portables.
752 This driver has been tested only on the Inspiron 8000 but it may
753 also work with other Dell laptops. You can force loading on other
754 models by passing the parameter `force=1' to the module. Use at
757 For information on utilities to make use of this driver see the
758 I8K Linux utilities web site at:
759 <http://people.debian.org/~dz/i8k/>
761 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
764 config X86_REBOOTFIXUPS
765 bool "Enable X86 board specific fixups for reboot"
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)
950 bool "PAE (Physical Address Extension) Support"
951 depends on X86_32 && !HIGHMEM4G
953 PAE is required for NX support, and furthermore enables
954 larger swapspace support for non-overcommit purposes. It
955 has the cost of more pagetable lookup overhead, and also
956 consumes more pagetable space per process.
958 config ARCH_PHYS_ADDR_T_64BIT
959 def_bool X86_64 || X86_PAE
961 # Common NUMA Features
963 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
965 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
967 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
969 Enable NUMA (Non Uniform Memory Access) support.
970 The kernel will try to allocate memory used by a CPU on the
971 local memory controller of the CPU and add some more
972 NUMA awareness to the kernel.
974 For 32-bit this is currently highly experimental and should be only
975 used for kernel development. It might also cause boot failures.
976 For 64-bit this is recommended on all multiprocessor Opteron systems.
977 If the system is EM64T, you should say N unless your system is
980 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
981 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
985 prompt "Old style AMD Opteron NUMA detection"
986 depends on X86_64 && NUMA && PCI
988 Enable K8 NUMA node topology detection. You should say Y here if
989 you have a multi processor AMD K8 system. This uses an old
990 method to read the NUMA configuration directly from the builtin
991 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
992 instead, which also takes priority if both are compiled in.
994 config X86_64_ACPI_NUMA
996 prompt "ACPI NUMA detection"
997 depends on X86_64 && NUMA && ACPI && PCI
1000 Enable ACPI SRAT based node topology detection.
1002 # Some NUMA nodes have memory ranges that span
1003 # other nodes. Even though a pfn is valid and
1004 # between a node's start and end pfns, it may not
1005 # reside on that node. See memmap_init_zone()
1007 config NODES_SPAN_OTHER_NODES
1009 depends on X86_64_ACPI_NUMA
1012 bool "NUMA emulation"
1013 depends on X86_64 && NUMA
1015 Enable NUMA emulation. A flat machine will be split
1016 into virtual nodes when booted with "numa=fake=N", where N is the
1017 number of nodes. This is only useful for debugging.
1020 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1022 default "9" if MAXSMP
1023 default "6" if X86_64
1024 default "4" if X86_NUMAQ
1026 depends on NEED_MULTIPLE_NODES
1028 Specify the maximum number of NUMA Nodes available on the target
1029 system. Increases memory reserved to accomodate various tables.
1031 config HAVE_ARCH_BOOTMEM_NODE
1033 depends on X86_32 && NUMA
1035 config ARCH_HAVE_MEMORY_PRESENT
1037 depends on X86_32 && DISCONTIGMEM
1039 config NEED_NODE_MEMMAP_SIZE
1041 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1043 config HAVE_ARCH_ALLOC_REMAP
1045 depends on X86_32 && NUMA
1047 config ARCH_FLATMEM_ENABLE
1049 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1051 config ARCH_DISCONTIGMEM_ENABLE
1053 depends on NUMA && X86_32
1055 config ARCH_DISCONTIGMEM_DEFAULT
1057 depends on NUMA && X86_32
1059 config ARCH_SPARSEMEM_DEFAULT
1063 config ARCH_SPARSEMEM_ENABLE
1065 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1066 select SPARSEMEM_STATIC if X86_32
1067 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1069 config ARCH_SELECT_MEMORY_MODEL
1071 depends on ARCH_SPARSEMEM_ENABLE
1073 config ARCH_MEMORY_PROBE
1075 depends on MEMORY_HOTPLUG
1080 bool "Allocate 3rd-level pagetables from highmem"
1081 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1083 The VM uses one page table entry for each page of physical memory.
1084 For systems with a lot of RAM, this can be wasteful of precious
1085 low memory. Setting this option will put user-space page table
1086 entries in high memory.
1088 config X86_CHECK_BIOS_CORRUPTION
1089 bool "Check for low memory corruption"
1091 Periodically check for memory corruption in low memory, which
1092 is suspected to be caused by BIOS. Even when enabled in the
1093 configuration, it is disabled at runtime. Enable it by
1094 setting "memory_corruption_check=1" on the kernel command
1095 line. By default it scans the low 64k of memory every 60
1096 seconds; see the memory_corruption_check_size and
1097 memory_corruption_check_period parameters in
1098 Documentation/kernel-parameters.txt to adjust this.
1100 When enabled with the default parameters, this option has
1101 almost no overhead, as it reserves a relatively small amount
1102 of memory and scans it infrequently. It both detects corruption
1103 and prevents it from affecting the running system.
1105 It is, however, intended as a diagnostic tool; if repeatable
1106 BIOS-originated corruption always affects the same memory,
1107 you can use memmap= to prevent the kernel from using that
1110 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1111 bool "Set the default setting of memory_corruption_check"
1112 depends on X86_CHECK_BIOS_CORRUPTION
1115 Set whether the default state of memory_corruption_check is
1118 config X86_RESERVE_LOW_64K
1119 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1122 Reserve the first 64K of physical RAM on BIOSes that are known
1123 to potentially corrupt that memory range. A numbers of BIOSes are
1124 known to utilize this area during suspend/resume, so it must not
1125 be used by the kernel.
1127 Set this to N if you are absolutely sure that you trust the BIOS
1128 to get all its memory reservations and usages right.
1130 If you have doubts about the BIOS (e.g. suspend/resume does not
1131 work or there's kernel crashes after certain hardware hotplug
1132 events) and it's not AMI or Phoenix, then you might want to enable
1133 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1134 corruption patterns.
1138 config MATH_EMULATION
1140 prompt "Math emulation" if X86_32
1142 Linux can emulate a math coprocessor (used for floating point
1143 operations) if you don't have one. 486DX and Pentium processors have
1144 a math coprocessor built in, 486SX and 386 do not, unless you added
1145 a 487DX or 387, respectively. (The messages during boot time can
1146 give you some hints here ["man dmesg"].) Everyone needs either a
1147 coprocessor or this emulation.
1149 If you don't have a math coprocessor, you need to say Y here; if you
1150 say Y here even though you have a coprocessor, the coprocessor will
1151 be used nevertheless. (This behavior can be changed with the kernel
1152 command line option "no387", which comes handy if your coprocessor
1153 is broken. Try "man bootparam" or see the documentation of your boot
1154 loader (lilo or loadlin) about how to pass options to the kernel at
1155 boot time.) This means that it is a good idea to say Y here if you
1156 intend to use this kernel on different machines.
1158 More information about the internals of the Linux math coprocessor
1159 emulation can be found in <file:arch/x86/math-emu/README>.
1161 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1162 kernel, it won't hurt.
1165 bool "MTRR (Memory Type Range Register) support"
1167 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1168 the Memory Type Range Registers (MTRRs) may be used to control
1169 processor access to memory ranges. This is most useful if you have
1170 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1171 allows bus write transfers to be combined into a larger transfer
1172 before bursting over the PCI/AGP bus. This can increase performance
1173 of image write operations 2.5 times or more. Saying Y here creates a
1174 /proc/mtrr file which may be used to manipulate your processor's
1175 MTRRs. Typically the X server should use this.
1177 This code has a reasonably generic interface so that similar
1178 control registers on other processors can be easily supported
1181 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1182 Registers (ARRs) which provide a similar functionality to MTRRs. For
1183 these, the ARRs are used to emulate the MTRRs.
1184 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1185 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1186 write-combining. All of these processors are supported by this code
1187 and it makes sense to say Y here if you have one of them.
1189 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1190 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1191 can lead to all sorts of problems, so it's good to say Y here.
1193 You can safely say Y even if your machine doesn't have MTRRs, you'll
1194 just add about 9 KB to your kernel.
1196 See <file:Documentation/x86/mtrr.txt> for more information.
1198 config MTRR_SANITIZER
1200 prompt "MTRR cleanup support"
1203 Convert MTRR layout from continuous to discrete, so X drivers can
1204 add writeback entries.
1206 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1207 The largest mtrr entry size for a continous block can be set with
1212 config MTRR_SANITIZER_ENABLE_DEFAULT
1213 int "MTRR cleanup enable value (0-1)"
1216 depends on MTRR_SANITIZER
1218 Enable mtrr cleanup default value
1220 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1221 int "MTRR cleanup spare reg num (0-7)"
1224 depends on MTRR_SANITIZER
1226 mtrr cleanup spare entries default, it can be changed via
1227 mtrr_spare_reg_nr=N on the kernel command line.
1231 prompt "x86 PAT support"
1234 Use PAT attributes to setup page level cache control.
1236 PATs are the modern equivalents of MTRRs and are much more
1237 flexible than MTRRs.
1239 Say N here if you see bootup problems (boot crash, boot hang,
1240 spontaneous reboots) or a non-working video driver.
1245 bool "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 seccomp to safely compute untrusted bytecode"
1262 This kernel feature is useful for number crunching applications
1263 that may need to compute untrusted bytecode during their
1264 execution. By using pipes or other transports made available to
1265 the process as file descriptors supporting the read/write
1266 syscalls, it's possible to isolate those applications in
1267 their own address space using seccomp. Once seccomp is
1268 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1269 and the task is only allowed to execute a few safe syscalls
1270 defined by each seccomp mode.
1272 If unsure, say Y. Only embedded should say N here.
1274 config CC_STACKPROTECTOR
1275 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1276 depends on X86_64 && EXPERIMENTAL && BROKEN
1278 This option turns on the -fstack-protector GCC feature. This
1279 feature puts, at the beginning of critical functions, a canary
1280 value on the stack just before the return address, and validates
1281 the value just before actually returning. Stack based buffer
1282 overflows (that need to overwrite this return address) now also
1283 overwrite the canary, which gets detected and the attack is then
1284 neutralized via a kernel panic.
1286 This feature requires gcc version 4.2 or above, or a distribution
1287 gcc with the feature backported. Older versions are automatically
1288 detected and for those versions, this configuration option is ignored.
1290 config CC_STACKPROTECTOR_ALL
1291 bool "Use stack-protector for all functions"
1292 depends on CC_STACKPROTECTOR
1294 Normally, GCC only inserts the canary value protection for
1295 functions that use large-ish on-stack buffers. By enabling
1296 this option, GCC will be asked to do this for ALL functions.
1298 source kernel/Kconfig.hz
1301 bool "kexec system call"
1302 depends on X86_BIOS_REBOOT
1304 kexec is a system call that implements the ability to shutdown your
1305 current kernel, and to start another kernel. It is like a reboot
1306 but it is independent of the system firmware. And like a reboot
1307 you can start any kernel with it, not just Linux.
1309 The name comes from the similarity to the exec system call.
1311 It is an ongoing process to be certain the hardware in a machine
1312 is properly shutdown, so do not be surprised if this code does not
1313 initially work for you. It may help to enable device hotplugging
1314 support. As of this writing the exact hardware interface is
1315 strongly in flux, so no good recommendation can be made.
1318 bool "kernel crash dumps"
1319 depends on X86_64 || (X86_32 && HIGHMEM)
1321 Generate crash dump after being started by kexec.
1322 This should be normally only set in special crash dump kernels
1323 which are loaded in the main kernel with kexec-tools into
1324 a specially reserved region and then later executed after
1325 a crash by kdump/kexec. The crash dump kernel must be compiled
1326 to a memory address not used by the main kernel or BIOS using
1327 PHYSICAL_START, or it must be built as a relocatable image
1328 (CONFIG_RELOCATABLE=y).
1329 For more details see Documentation/kdump/kdump.txt
1332 bool "kexec jump (EXPERIMENTAL)"
1333 depends on EXPERIMENTAL
1334 depends on KEXEC && HIBERNATION && X86_32
1336 Jump between original kernel and kexeced kernel and invoke
1337 code in physical address mode via KEXEC
1339 config PHYSICAL_START
1340 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1341 default "0x1000000" if X86_NUMAQ
1342 default "0x200000" if X86_64
1345 This gives the physical address where the kernel is loaded.
1347 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1348 bzImage will decompress itself to above physical address and
1349 run from there. Otherwise, bzImage will run from the address where
1350 it has been loaded by the boot loader and will ignore above physical
1353 In normal kdump cases one does not have to set/change this option
1354 as now bzImage can be compiled as a completely relocatable image
1355 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1356 address. This option is mainly useful for the folks who don't want
1357 to use a bzImage for capturing the crash dump and want to use a
1358 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1359 to be specifically compiled to run from a specific memory area
1360 (normally a reserved region) and this option comes handy.
1362 So if you are using bzImage for capturing the crash dump, leave
1363 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1364 Otherwise if you plan to use vmlinux for capturing the crash dump
1365 change this value to start of the reserved region (Typically 16MB
1366 0x1000000). In other words, it can be set based on the "X" value as
1367 specified in the "crashkernel=YM@XM" command line boot parameter
1368 passed to the panic-ed kernel. Typically this parameter is set as
1369 crashkernel=64M@16M. Please take a look at
1370 Documentation/kdump/kdump.txt for more details about crash dumps.
1372 Usage of bzImage for capturing the crash dump is recommended as
1373 one does not have to build two kernels. Same kernel can be used
1374 as production kernel and capture kernel. Above option should have
1375 gone away after relocatable bzImage support is introduced. But it
1376 is present because there are users out there who continue to use
1377 vmlinux for dump capture. This option should go away down the
1380 Don't change this unless you know what you are doing.
1383 bool "Build a relocatable kernel (EXPERIMENTAL)"
1384 depends on EXPERIMENTAL
1386 This builds a kernel image that retains relocation information
1387 so it can be loaded someplace besides the default 1MB.
1388 The relocations tend to make the kernel binary about 10% larger,
1389 but are discarded at runtime.
1391 One use is for the kexec on panic case where the recovery kernel
1392 must live at a different physical address than the primary
1395 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1396 it has been loaded at and the compile time physical address
1397 (CONFIG_PHYSICAL_START) is ignored.
1399 config PHYSICAL_ALIGN
1401 prompt "Alignment value to which kernel should be aligned" if X86_32
1402 default "0x100000" if X86_32
1403 default "0x200000" if X86_64
1404 range 0x2000 0x400000
1406 This value puts the alignment restrictions on physical address
1407 where kernel is loaded and run from. Kernel is compiled for an
1408 address which meets above alignment restriction.
1410 If bootloader loads the kernel at a non-aligned address and
1411 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1412 address aligned to above value and run from there.
1414 If bootloader loads the kernel at a non-aligned address and
1415 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1416 load address and decompress itself to the address it has been
1417 compiled for and run from there. The address for which kernel is
1418 compiled already meets above alignment restrictions. Hence the
1419 end result is that kernel runs from a physical address meeting
1420 above alignment restrictions.
1422 Don't change this unless you know what you are doing.
1425 bool "Support for hot-pluggable CPUs"
1426 depends on SMP && HOTPLUG && !X86_VOYAGER
1428 Say Y here to allow turning CPUs off and on. CPUs can be
1429 controlled through /sys/devices/system/cpu.
1430 ( Note: power management support will enable this option
1431 automatically on SMP systems. )
1432 Say N if you want to disable CPU hotplug.
1436 prompt "Compat VDSO support"
1437 depends on X86_32 || IA32_EMULATION
1439 Map the 32-bit VDSO to the predictable old-style address too.
1441 Say N here if you are running a sufficiently recent glibc
1442 version (2.3.3 or later), to remove the high-mapped
1443 VDSO mapping and to exclusively use the randomized VDSO.
1448 bool "Built-in kernel command line"
1451 Allow for specifying boot arguments to the kernel at
1452 build time. On some systems (e.g. embedded ones), it is
1453 necessary or convenient to provide some or all of the
1454 kernel boot arguments with the kernel itself (that is,
1455 to not rely on the boot loader to provide them.)
1457 To compile command line arguments into the kernel,
1458 set this option to 'Y', then fill in the
1459 the boot arguments in CONFIG_CMDLINE.
1461 Systems with fully functional boot loaders (i.e. non-embedded)
1462 should leave this option set to 'N'.
1465 string "Built-in kernel command string"
1466 depends on CMDLINE_BOOL
1469 Enter arguments here that should be compiled into the kernel
1470 image and used at boot time. If the boot loader provides a
1471 command line at boot time, it is appended to this string to
1472 form the full kernel command line, when the system boots.
1474 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1475 change this behavior.
1477 In most cases, the command line (whether built-in or provided
1478 by the boot loader) should specify the device for the root
1481 config CMDLINE_OVERRIDE
1482 bool "Built-in command line overrides boot loader arguments"
1484 depends on CMDLINE_BOOL
1486 Set this option to 'Y' to have the kernel ignore the boot loader
1487 command line, and use ONLY the built-in command line.
1489 This is used to work around broken boot loaders. This should
1490 be set to 'N' under normal conditions.
1494 config ARCH_ENABLE_MEMORY_HOTPLUG
1496 depends on X86_64 || (X86_32 && HIGHMEM)
1498 config HAVE_ARCH_EARLY_PFN_TO_NID
1502 menu "Power management and ACPI options"
1503 depends on !X86_VOYAGER
1505 config ARCH_HIBERNATION_HEADER
1507 depends on X86_64 && HIBERNATION
1509 source "kernel/power/Kconfig"
1511 source "drivers/acpi/Kconfig"
1516 depends on APM || APM_MODULE
1519 tristate "APM (Advanced Power Management) BIOS support"
1520 depends on X86_32 && PM_SLEEP
1522 APM is a BIOS specification for saving power using several different
1523 techniques. This is mostly useful for battery powered laptops with
1524 APM compliant BIOSes. If you say Y here, the system time will be
1525 reset after a RESUME operation, the /proc/apm device will provide
1526 battery status information, and user-space programs will receive
1527 notification of APM "events" (e.g. battery status change).
1529 If you select "Y" here, you can disable actual use of the APM
1530 BIOS by passing the "apm=off" option to the kernel at boot time.
1532 Note that the APM support is almost completely disabled for
1533 machines with more than one CPU.
1535 In order to use APM, you will need supporting software. For location
1536 and more information, read <file:Documentation/power/pm.txt> and the
1537 Battery Powered Linux mini-HOWTO, available from
1538 <http://www.tldp.org/docs.html#howto>.
1540 This driver does not spin down disk drives (see the hdparm(8)
1541 manpage ("man 8 hdparm") for that), and it doesn't turn off
1542 VESA-compliant "green" monitors.
1544 This driver does not support the TI 4000M TravelMate and the ACER
1545 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1546 desktop machines also don't have compliant BIOSes, and this driver
1547 may cause those machines to panic during the boot phase.
1549 Generally, if you don't have a battery in your machine, there isn't
1550 much point in using this driver and you should say N. If you get
1551 random kernel OOPSes or reboots that don't seem to be related to
1552 anything, try disabling/enabling this option (or disabling/enabling
1555 Some other things you should try when experiencing seemingly random,
1558 1) make sure that you have enough swap space and that it is
1560 2) pass the "no-hlt" option to the kernel
1561 3) switch on floating point emulation in the kernel and pass
1562 the "no387" option to the kernel
1563 4) pass the "floppy=nodma" option to the kernel
1564 5) pass the "mem=4M" option to the kernel (thereby disabling
1565 all but the first 4 MB of RAM)
1566 6) make sure that the CPU is not over clocked.
1567 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1568 8) disable the cache from your BIOS settings
1569 9) install a fan for the video card or exchange video RAM
1570 10) install a better fan for the CPU
1571 11) exchange RAM chips
1572 12) exchange the motherboard.
1574 To compile this driver as a module, choose M here: the
1575 module will be called apm.
1579 config APM_IGNORE_USER_SUSPEND
1580 bool "Ignore USER SUSPEND"
1582 This option will ignore USER SUSPEND requests. On machines with a
1583 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1584 series notebooks, it is necessary to say Y because of a BIOS bug.
1586 config APM_DO_ENABLE
1587 bool "Enable PM at boot time"
1589 Enable APM features at boot time. From page 36 of the APM BIOS
1590 specification: "When disabled, the APM BIOS does not automatically
1591 power manage devices, enter the Standby State, enter the Suspend
1592 State, or take power saving steps in response to CPU Idle calls."
1593 This driver will make CPU Idle calls when Linux is idle (unless this
1594 feature is turned off -- see "Do CPU IDLE calls", below). This
1595 should always save battery power, but more complicated APM features
1596 will be dependent on your BIOS implementation. You may need to turn
1597 this option off if your computer hangs at boot time when using APM
1598 support, or if it beeps continuously instead of suspending. Turn
1599 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1600 T400CDT. This is off by default since most machines do fine without
1604 bool "Make CPU Idle calls when idle"
1606 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1607 On some machines, this can activate improved power savings, such as
1608 a slowed CPU clock rate, when the machine is idle. These idle calls
1609 are made after the idle loop has run for some length of time (e.g.,
1610 333 mS). On some machines, this will cause a hang at boot time or
1611 whenever the CPU becomes idle. (On machines with more than one CPU,
1612 this option does nothing.)
1614 config APM_DISPLAY_BLANK
1615 bool "Enable console blanking using APM"
1617 Enable console blanking using the APM. Some laptops can use this to
1618 turn off the LCD backlight when the screen blanker of the Linux
1619 virtual console blanks the screen. Note that this is only used by
1620 the virtual console screen blanker, and won't turn off the backlight
1621 when using the X Window system. This also doesn't have anything to
1622 do with your VESA-compliant power-saving monitor. Further, this
1623 option doesn't work for all laptops -- it might not turn off your
1624 backlight at all, or it might print a lot of errors to the console,
1625 especially if you are using gpm.
1627 config APM_ALLOW_INTS
1628 bool "Allow interrupts during APM BIOS calls"
1630 Normally we disable external interrupts while we are making calls to
1631 the APM BIOS as a measure to lessen the effects of a badly behaving
1632 BIOS implementation. The BIOS should reenable interrupts if it
1633 needs to. Unfortunately, some BIOSes do not -- especially those in
1634 many of the newer IBM Thinkpads. If you experience hangs when you
1635 suspend, try setting this to Y. Otherwise, say N.
1637 config APM_REAL_MODE_POWER_OFF
1638 bool "Use real mode APM BIOS call to power off"
1640 Use real mode APM BIOS calls to switch off the computer. This is
1641 a work-around for a number of buggy BIOSes. Switch this option on if
1642 your computer crashes instead of powering off properly.
1646 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1648 source "drivers/cpuidle/Kconfig"
1650 source "drivers/idle/Kconfig"
1655 menu "Bus options (PCI etc.)"
1660 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1662 Find out whether you have a PCI motherboard. PCI is the name of a
1663 bus system, i.e. the way the CPU talks to the other stuff inside
1664 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1665 VESA. If you have PCI, say Y, otherwise N.
1668 prompt "PCI access mode"
1669 depends on X86_32 && PCI
1672 On PCI systems, the BIOS can be used to detect the PCI devices and
1673 determine their configuration. However, some old PCI motherboards
1674 have BIOS bugs and may crash if this is done. Also, some embedded
1675 PCI-based systems don't have any BIOS at all. Linux can also try to
1676 detect the PCI hardware directly without using the BIOS.
1678 With this option, you can specify how Linux should detect the
1679 PCI devices. If you choose "BIOS", the BIOS will be used,
1680 if you choose "Direct", the BIOS won't be used, and if you
1681 choose "MMConfig", then PCI Express MMCONFIG will be used.
1682 If you choose "Any", the kernel will try MMCONFIG, then the
1683 direct access method and falls back to the BIOS if that doesn't
1684 work. If unsure, go with the default, which is "Any".
1689 config PCI_GOMMCONFIG
1706 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1708 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1711 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1715 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1719 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1726 bool "Support mmconfig PCI config space access"
1727 depends on X86_64 && PCI && ACPI
1730 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1731 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1733 DMA remapping (DMAR) devices support enables independent address
1734 translations for Direct Memory Access (DMA) from devices.
1735 These DMA remapping devices are reported via ACPI tables
1736 and include PCI device scope covered by these DMA
1741 prompt "Support for Graphics workaround"
1744 Current Graphics drivers tend to use physical address
1745 for DMA and avoid using DMA APIs. Setting this config
1746 option permits the IOMMU driver to set a unity map for
1747 all the OS-visible memory. Hence the driver can continue
1748 to use physical addresses for DMA.
1750 config DMAR_FLOPPY_WA
1754 Floppy disk drivers are know to bypass DMA API calls
1755 thereby failing to work when IOMMU is enabled. This
1756 workaround will setup a 1:1 mapping for the first
1757 16M to make floppy (an ISA device) work.
1760 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1761 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1763 Supports Interrupt remapping for IO-APIC and MSI devices.
1764 To use x2apic mode in the CPU's which support x2APIC enhancements or
1765 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1767 source "drivers/pci/pcie/Kconfig"
1769 source "drivers/pci/Kconfig"
1771 # x86_64 have no ISA slots, but do have ISA-style DMA.
1779 depends on !X86_VOYAGER
1781 Find out whether you have ISA slots on your motherboard. ISA is the
1782 name of a bus system, i.e. the way the CPU talks to the other stuff
1783 inside your box. Other bus systems are PCI, EISA, MicroChannel
1784 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1785 newer boards don't support it. If you have ISA, say Y, otherwise N.
1791 The Extended Industry Standard Architecture (EISA) bus was
1792 developed as an open alternative to the IBM MicroChannel bus.
1794 The EISA bus provided some of the features of the IBM MicroChannel
1795 bus while maintaining backward compatibility with cards made for
1796 the older ISA bus. The EISA bus saw limited use between 1988 and
1797 1995 when it was made obsolete by the PCI bus.
1799 Say Y here if you are building a kernel for an EISA-based machine.
1803 source "drivers/eisa/Kconfig"
1806 bool "MCA support" if !X86_VOYAGER
1807 default y if X86_VOYAGER
1809 MicroChannel Architecture is found in some IBM PS/2 machines and
1810 laptops. It is a bus system similar to PCI or ISA. See
1811 <file:Documentation/mca.txt> (and especially the web page given
1812 there) before attempting to build an MCA bus kernel.
1814 source "drivers/mca/Kconfig"
1817 tristate "NatSemi SCx200 support"
1818 depends on !X86_VOYAGER
1820 This provides basic support for National Semiconductor's
1821 (now AMD's) Geode processors. The driver probes for the
1822 PCI-IDs of several on-chip devices, so its a good dependency
1823 for other scx200_* drivers.
1825 If compiled as a module, the driver is named scx200.
1827 config SCx200HR_TIMER
1828 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1829 depends on SCx200 && GENERIC_TIME
1832 This driver provides a clocksource built upon the on-chip
1833 27MHz high-resolution timer. Its also a workaround for
1834 NSC Geode SC-1100's buggy TSC, which loses time when the
1835 processor goes idle (as is done by the scheduler). The
1836 other workaround is idle=poll boot option.
1838 config GEODE_MFGPT_TIMER
1840 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1841 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1843 This driver provides a clock event source based on the MFGPT
1844 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1845 MFGPTs have a better resolution and max interval than the
1846 generic PIT, and are suitable for use as high-res timers.
1849 bool "One Laptop Per Child support"
1852 Add support for detecting the unique features of the OLPC
1859 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1861 source "drivers/pcmcia/Kconfig"
1863 source "drivers/pci/hotplug/Kconfig"
1868 menu "Executable file formats / Emulations"
1870 source "fs/Kconfig.binfmt"
1872 config IA32_EMULATION
1873 bool "IA32 Emulation"
1875 select COMPAT_BINFMT_ELF
1877 Include code to run 32-bit programs under a 64-bit kernel. You should
1878 likely turn this on, unless you're 100% sure that you don't have any
1879 32-bit programs left.
1882 tristate "IA32 a.out support"
1883 depends on IA32_EMULATION
1885 Support old a.out binaries in the 32bit emulation.
1889 depends on IA32_EMULATION
1891 config COMPAT_FOR_U64_ALIGNMENT
1895 config SYSVIPC_COMPAT
1897 depends on COMPAT && SYSVIPC
1902 config HAVE_ATOMIC_IOMAP
1906 source "net/Kconfig"
1908 source "drivers/Kconfig"
1910 source "drivers/firmware/Kconfig"
1914 source "arch/x86/Kconfig.debug"
1916 source "security/Kconfig"
1918 source "crypto/Kconfig"
1920 source "arch/x86/kvm/Kconfig"
1922 source "lib/Kconfig"
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