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_DYNAMIC_FTRACE
31 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
32 select HAVE_ARCH_KGDB if !X86_VOYAGER
33 select HAVE_ARCH_TRACEHOOK
34 select HAVE_GENERIC_DMA_COHERENT if X86_32
35 select HAVE_EFFICIENT_UNALIGNED_ACCESS
40 default "arch/x86/configs/i386_defconfig" if X86_32
41 default "arch/x86/configs/x86_64_defconfig" if X86_64
44 config GENERIC_LOCKBREAK
50 config GENERIC_CMOS_UPDATE
53 config CLOCKSOURCE_WATCHDOG
56 config GENERIC_CLOCKEVENTS
59 config GENERIC_CLOCKEVENTS_BROADCAST
61 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
63 config LOCKDEP_SUPPORT
66 config STACKTRACE_SUPPORT
69 config HAVE_LATENCYTOP_SUPPORT
72 config FAST_CMPXCHG_LOCAL
85 config GENERIC_ISA_DMA
95 config GENERIC_HWEIGHT
101 config ARCH_MAY_HAVE_PC_FDC
104 config RWSEM_GENERIC_SPINLOCK
107 config RWSEM_XCHGADD_ALGORITHM
110 config ARCH_HAS_ILOG2_U32
113 config ARCH_HAS_ILOG2_U64
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_CACHE_LINE_SIZE
132 config HAVE_SETUP_PER_CPU_AREA
133 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
135 config HAVE_CPUMASK_OF_CPU_MAP
138 config ARCH_HIBERNATION_POSSIBLE
140 depends on !SMP || !X86_VOYAGER
142 config ARCH_SUSPEND_POSSIBLE
144 depends on !X86_VOYAGER
150 config ARCH_POPULATES_NODE_MAP
157 config ARCH_SUPPORTS_OPTIMIZED_INLINING
160 # Use the generic interrupt handling code in kernel/irq/:
161 config GENERIC_HARDIRQS
165 config GENERIC_IRQ_PROBE
169 config GENERIC_PENDING_IRQ
171 depends on GENERIC_HARDIRQS && SMP
176 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
177 select USE_GENERIC_SMP_HELPERS
182 depends on X86_32 && SMP
186 depends on X86_64 && SMP
191 depends on (X86_32 && !X86_VOYAGER) || X86_64
194 config X86_BIOS_REBOOT
196 depends on !X86_VOYAGER
199 config X86_TRAMPOLINE
201 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
206 source "init/Kconfig"
208 menu "Processor type and features"
210 source "kernel/time/Kconfig"
213 bool "Symmetric multi-processing support"
215 This enables support for systems with more than one CPU. If you have
216 a system with only one CPU, like most personal computers, say N. If
217 you have a system with more than one CPU, say Y.
219 If you say N here, the kernel will run on single and multiprocessor
220 machines, but will use only one CPU of a multiprocessor machine. If
221 you say Y here, the kernel will run on many, but not all,
222 singleprocessor machines. On a singleprocessor machine, the kernel
223 will run faster if you say N here.
225 Note that if you say Y here and choose architecture "586" or
226 "Pentium" under "Processor family", the kernel will not work on 486
227 architectures. Similarly, multiprocessor kernels for the "PPro"
228 architecture may not work on all Pentium based boards.
230 People using multiprocessor machines who say Y here should also say
231 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
232 Management" code will be disabled if you say Y here.
234 See also <file:Documentation/i386/IO-APIC.txt>,
235 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
236 <http://www.tldp.org/docs.html#howto>.
238 If you don't know what to do here, say N.
240 config X86_FIND_SMP_CONFIG
242 depends on X86_MPPARSE || X86_VOYAGER
247 bool "Enable MPS table"
248 depends on X86_LOCAL_APIC
250 For old smp systems that do not have proper acpi support. Newer systems
251 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
257 depends on X86_LOCAL_APIC
261 prompt "Subarchitecture Type"
267 Choose this option if your computer is a standard PC or compatible.
273 Select this for an AMD Elan processor.
275 Do not use this option for K6/Athlon/Opteron processors!
277 If unsure, choose "PC-compatible" instead.
281 depends on X86_32 && (SMP || BROKEN) && !PCI
283 Voyager is an MCA-based 32-way capable SMP architecture proprietary
284 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
288 If you do not specifically know you have a Voyager based machine,
289 say N here, otherwise the kernel you build will not be bootable.
291 config X86_GENERICARCH
292 bool "Generic architecture"
295 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
296 subarchitectures. It is intended for a generic binary kernel.
297 if you select them all, kernel will probe it one by one. and will
303 bool "NUMAQ (IBM/Sequent)"
304 depends on SMP && X86_32 && PCI && X86_MPPARSE
307 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
308 NUMA multiquad box. This changes the way that processors are
309 bootstrapped, and uses Clustered Logical APIC addressing mode instead
310 of Flat Logical. You will need a new lynxer.elf file to flash your
311 firmware with - send email to <Martin.Bligh@us.ibm.com>.
314 bool "Summit/EXA (IBM x440)"
315 depends on X86_32 && SMP
317 This option is needed for IBM systems that use the Summit/EXA chipset.
318 In particular, it is needed for the x440.
321 bool "Support for Unisys ES7000 IA32 series"
322 depends on X86_32 && SMP
324 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
325 supposed to run on an IA32-based Unisys ES7000 system.
328 bool "Support for big SMP systems with more than 8 CPUs"
329 depends on X86_32 && SMP
331 This option is needed for the systems that have more than 8 CPUs
332 and if the system is not of any sub-arch type above.
337 bool "Support for ScaleMP vSMP"
339 depends on X86_64 && PCI
341 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
342 supposed to run on these EM64T-based machines. Only choose this option
343 if you have one of these machines.
348 bool "SGI 320/540 (Visual Workstation)"
349 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
351 The SGI Visual Workstation series is an IA32-based workstation
352 based on SGI systems chips with some legacy PC hardware attached.
354 Say Y here to create a kernel to run on the SGI 320 or 540.
356 A kernel compiled for the Visual Workstation will run on general
357 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
360 bool "RDC R-321x SoC"
363 select X86_REBOOTFIXUPS
365 This option is needed for RDC R-321x system-on-chip, also known
367 If you don't have one of these chips, you should say N here.
369 config SCHED_NO_NO_OMIT_FRAME_POINTER
371 prompt "Single-depth WCHAN output"
374 Calculate simpler /proc/<PID>/wchan values. If this option
375 is disabled then wchan values will recurse back to the
376 caller function. This provides more accurate wchan values,
377 at the expense of slightly more scheduling overhead.
379 If in doubt, say "Y".
381 menuconfig PARAVIRT_GUEST
382 bool "Paravirtualized guest support"
384 Say Y here to get to see options related to running Linux under
385 various hypervisors. This option alone does not add any kernel code.
387 If you say N, all options in this submenu will be skipped and disabled.
391 source "arch/x86/xen/Kconfig"
394 bool "VMI Guest support"
397 depends on !X86_VOYAGER
399 VMI provides a paravirtualized interface to the VMware ESX server
400 (it could be used by other hypervisors in theory too, but is not
401 at the moment), by linking the kernel to a GPL-ed ROM module
402 provided by the hypervisor.
405 bool "KVM paravirtualized clock"
407 select PARAVIRT_CLOCK
408 depends on !X86_VOYAGER
410 Turning on this option will allow you to run a paravirtualized clock
411 when running over the KVM hypervisor. Instead of relying on a PIT
412 (or probably other) emulation by the underlying device model, the host
413 provides the guest with timing infrastructure such as time of day, and
417 bool "KVM Guest support"
419 depends on !X86_VOYAGER
421 This option enables various optimizations for running under the KVM
424 source "arch/x86/lguest/Kconfig"
427 bool "Enable paravirtualization code"
428 depends on !X86_VOYAGER
430 This changes the kernel so it can modify itself when it is run
431 under a hypervisor, potentially improving performance significantly
432 over full virtualization. However, when run without a hypervisor
433 the kernel is theoretically slower and slightly larger.
435 config PARAVIRT_CLOCK
441 config PARAVIRT_DEBUG
442 bool "paravirt-ops debugging"
443 depends on PARAVIRT && DEBUG_KERNEL
445 Enable to debug paravirt_ops internals. Specifically, BUG if
446 a paravirt_op is missing when it is called.
451 This option adds a kernel parameter 'memtest', which allows memtest
453 memtest=0, mean disabled; -- default
454 memtest=1, mean do 1 test pattern;
456 memtest=4, mean do 4 test patterns.
457 If you are unsure how to answer this question, answer N.
459 config X86_SUMMIT_NUMA
461 depends on X86_32 && NUMA && X86_GENERICARCH
463 config X86_CYCLONE_TIMER
465 depends on X86_GENERICARCH
467 config ES7000_CLUSTERED_APIC
469 depends on SMP && X86_ES7000 && MPENTIUMIII
471 source "arch/x86/Kconfig.cpu"
475 prompt "HPET Timer Support" if X86_32
477 Use the IA-PC HPET (High Precision Event Timer) to manage
478 time in preference to the PIT and RTC, if a HPET is
480 HPET is the next generation timer replacing legacy 8254s.
481 The HPET provides a stable time base on SMP
482 systems, unlike the TSC, but it is more expensive to access,
483 as it is off-chip. You can find the HPET spec at
484 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
486 You can safely choose Y here. However, HPET will only be
487 activated if the platform and the BIOS support this feature.
488 Otherwise the 8254 will be used for timing services.
490 Choose N to continue using the legacy 8254 timer.
492 config HPET_EMULATE_RTC
494 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
496 # Mark as embedded because too many people got it wrong.
497 # The code disables itself when not needed.
500 bool "Enable DMI scanning" if EMBEDDED
502 Enabled scanning of DMI to identify machine quirks. Say Y
503 here unless you have verified that your setup is not
504 affected by entries in the DMI blacklist. Required by PNP
508 bool "GART IOMMU support" if EMBEDDED
512 depends on X86_64 && PCI
514 Support for full DMA access of devices with 32bit memory access only
515 on systems with more than 3GB. This is usually needed for USB,
516 sound, many IDE/SATA chipsets and some other devices.
517 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
518 based hardware IOMMU and a software bounce buffer based IOMMU used
519 on Intel systems and as fallback.
520 The code is only active when needed (enough memory and limited
521 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
525 bool "IBM Calgary IOMMU support"
527 depends on X86_64 && PCI && EXPERIMENTAL
529 Support for hardware IOMMUs in IBM's xSeries x366 and x460
530 systems. Needed to run systems with more than 3GB of memory
531 properly with 32-bit PCI devices that do not support DAC
532 (Double Address Cycle). Calgary also supports bus level
533 isolation, where all DMAs pass through the IOMMU. This
534 prevents them from going anywhere except their intended
535 destination. This catches hard-to-find kernel bugs and
536 mis-behaving drivers and devices that do not use the DMA-API
537 properly to set up their DMA buffers. The IOMMU can be
538 turned off at boot time with the iommu=off parameter.
539 Normally the kernel will make the right choice by itself.
542 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
544 prompt "Should Calgary be enabled by default?"
545 depends on CALGARY_IOMMU
547 Should Calgary be enabled by default? if you choose 'y', Calgary
548 will be used (if it exists). If you choose 'n', Calgary will not be
549 used even if it exists. If you choose 'n' and would like to use
550 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
554 bool "AMD IOMMU support"
557 depends on X86_64 && PCI && ACPI
559 With this option you can enable support for AMD IOMMU hardware in
560 your system. An IOMMU is a hardware component which provides
561 remapping of DMA memory accesses from devices. With an AMD IOMMU you
562 can isolate the the DMA memory of different devices and protect the
563 system from misbehaving device drivers or hardware.
565 You can find out if your system has an AMD IOMMU if you look into
566 your BIOS for an option to enable it or if you have an IVRS ACPI
569 # need this always selected by IOMMU for the VIA workaround
573 Support for software bounce buffers used on x86-64 systems
574 which don't have a hardware IOMMU (e.g. the current generation
575 of Intel's x86-64 CPUs). Using this PCI devices which can only
576 access 32-bits of memory can be used on systems with more than
577 3 GB of memory. If unsure, say Y.
580 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
583 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
584 depends on X86_64 && SMP && BROKEN
587 Configure maximum number of CPUS and NUMA Nodes for this architecture.
591 int "Maximum number of CPUs (2-512)" if !MAXSMP
594 default "4096" if MAXSMP
595 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
598 This allows you to specify the maximum number of CPUs which this
599 kernel will support. The maximum supported value is 512 and the
600 minimum value which makes sense is 2.
602 This is purely to save memory - each supported CPU adds
603 approximately eight kilobytes to the kernel image.
606 bool "SMT (Hyperthreading) scheduler support"
609 SMT scheduler support improves the CPU scheduler's decision making
610 when dealing with Intel Pentium 4 chips with HyperThreading at a
611 cost of slightly increased overhead in some places. If unsure say
616 prompt "Multi-core scheduler support"
619 Multi-core scheduler support improves the CPU scheduler's decision
620 making when dealing with multi-core CPU chips at a cost of slightly
621 increased overhead in some places. If unsure say N here.
623 source "kernel/Kconfig.preempt"
626 bool "Local APIC support on uniprocessors"
627 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
629 A local APIC (Advanced Programmable Interrupt Controller) is an
630 integrated interrupt controller in the CPU. If you have a single-CPU
631 system which has a processor with a local APIC, you can say Y here to
632 enable and use it. If you say Y here even though your machine doesn't
633 have a local APIC, then the kernel will still run with no slowdown at
634 all. The local APIC supports CPU-generated self-interrupts (timer,
635 performance counters), and the NMI watchdog which detects hard
639 bool "IO-APIC support on uniprocessors"
640 depends on X86_UP_APIC
642 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
643 SMP-capable replacement for PC-style interrupt controllers. Most
644 SMP systems and many recent uniprocessor systems have one.
646 If you have a single-CPU system with an IO-APIC, you can say Y here
647 to use it. If you say Y here even though your machine doesn't have
648 an IO-APIC, then the kernel will still run with no slowdown at all.
650 config X86_LOCAL_APIC
652 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
656 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
658 config X86_VISWS_APIC
660 depends on X86_32 && X86_VISWS
663 bool "Machine Check Exception"
664 depends on !X86_VOYAGER
666 Machine Check Exception support allows the processor to notify the
667 kernel if it detects a problem (e.g. overheating, component failure).
668 The action the kernel takes depends on the severity of the problem,
669 ranging from a warning message on the console, to halting the machine.
670 Your processor must be a Pentium or newer to support this - check the
671 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
672 have a design flaw which leads to false MCE events - hence MCE is
673 disabled on all P5 processors, unless explicitly enabled with "mce"
674 as a boot argument. Similarly, if MCE is built in and creates a
675 problem on some new non-standard machine, you can boot with "nomce"
676 to disable it. MCE support simply ignores non-MCE processors like
677 the 386 and 486, so nearly everyone can say Y here.
681 prompt "Intel MCE features"
682 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
684 Additional support for intel specific MCE features such as
689 prompt "AMD MCE features"
690 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
692 Additional support for AMD specific MCE features such as
693 the DRAM Error Threshold.
695 config X86_MCE_NONFATAL
696 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
697 depends on X86_32 && X86_MCE
699 Enabling this feature starts a timer that triggers every 5 seconds which
700 will look at the machine check registers to see if anything happened.
701 Non-fatal problems automatically get corrected (but still logged).
702 Disable this if you don't want to see these messages.
703 Seeing the messages this option prints out may be indicative of dying
704 or out-of-spec (ie, overclocked) hardware.
705 This option only does something on certain CPUs.
706 (AMD Athlon/Duron and Intel Pentium 4)
708 config X86_MCE_P4THERMAL
709 bool "check for P4 thermal throttling interrupt."
710 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
712 Enabling this feature will cause a message to be printed when the P4
713 enters thermal throttling.
716 bool "Enable VM86 support" if EMBEDDED
720 This option is required by programs like DOSEMU to run 16-bit legacy
721 code on X86 processors. It also may be needed by software like
722 XFree86 to initialize some video cards via BIOS. Disabling this
723 option saves about 6k.
726 tristate "Toshiba Laptop support"
729 This adds a driver to safely access the System Management Mode of
730 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
731 not work on models with a Phoenix BIOS. The System Management Mode
732 is used to set the BIOS and power saving options on Toshiba portables.
734 For information on utilities to make use of this driver see the
735 Toshiba Linux utilities web site at:
736 <http://www.buzzard.org.uk/toshiba/>.
738 Say Y if you intend to run this kernel on a Toshiba portable.
742 tristate "Dell laptop support"
744 This adds a driver to safely access the System Management Mode
745 of the CPU on the Dell Inspiron 8000. The System Management Mode
746 is used to read cpu temperature and cooling fan status and to
747 control the fans on the I8K portables.
749 This driver has been tested only on the Inspiron 8000 but it may
750 also work with other Dell laptops. You can force loading on other
751 models by passing the parameter `force=1' to the module. Use at
754 For information on utilities to make use of this driver see the
755 I8K Linux utilities web site at:
756 <http://people.debian.org/~dz/i8k/>
758 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
761 config X86_REBOOTFIXUPS
763 prompt "Enable X86 board specific fixups for reboot"
764 depends on X86_32 && X86
766 This enables chipset and/or board specific fixups to be done
767 in order to get reboot to work correctly. This is only needed on
768 some combinations of hardware and BIOS. The symptom, for which
769 this config is intended, is when reboot ends with a stalled/hung
772 Currently, the only fixup is for the Geode machines using
773 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
775 Say Y if you want to enable the fixup. Currently, it's safe to
776 enable this option even if you don't need it.
780 tristate "/dev/cpu/microcode - microcode support"
783 If you say Y here, you will be able to update the microcode on
784 certain Intel and AMD processors. The Intel support is for the
785 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
786 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
787 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
788 You will obviously need the actual microcode binary data itself
789 which is not shipped with the Linux kernel.
791 This option selects the general module only, you need to select
792 at least one vendor specific module as well.
794 To compile this driver as a module, choose M here: the
795 module will be called microcode.
797 config MICROCODE_INTEL
798 bool "Intel microcode patch loading support"
803 This options enables microcode patch loading support for Intel
806 For latest news and information on obtaining all the required
807 Intel ingredients for this driver, check:
808 <http://www.urbanmyth.org/microcode/>.
811 bool "AMD microcode patch loading support"
815 If you select this option, microcode patch loading support for AMD
816 processors will be enabled.
818 config MICROCODE_OLD_INTERFACE
823 tristate "/dev/cpu/*/msr - Model-specific register support"
825 This device gives privileged processes access to the x86
826 Model-Specific Registers (MSRs). It is a character device with
827 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
828 MSR accesses are directed to a specific CPU on multi-processor
832 tristate "/dev/cpu/*/cpuid - CPU information support"
834 This device gives processes access to the x86 CPUID instruction to
835 be executed on a specific processor. It is a character device
836 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
840 prompt "High Memory Support"
841 default HIGHMEM4G if !X86_NUMAQ
842 default HIGHMEM64G if X86_NUMAQ
847 depends on !X86_NUMAQ
849 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
850 However, the address space of 32-bit x86 processors is only 4
851 Gigabytes large. That means that, if you have a large amount of
852 physical memory, not all of it can be "permanently mapped" by the
853 kernel. The physical memory that's not permanently mapped is called
856 If you are compiling a kernel which will never run on a machine with
857 more than 1 Gigabyte total physical RAM, answer "off" here (default
858 choice and suitable for most users). This will result in a "3GB/1GB"
859 split: 3GB are mapped so that each process sees a 3GB virtual memory
860 space and the remaining part of the 4GB virtual memory space is used
861 by the kernel to permanently map as much physical memory as
864 If the machine has between 1 and 4 Gigabytes physical RAM, then
867 If more than 4 Gigabytes is used then answer "64GB" here. This
868 selection turns Intel PAE (Physical Address Extension) mode on.
869 PAE implements 3-level paging on IA32 processors. PAE is fully
870 supported by Linux, PAE mode is implemented on all recent Intel
871 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
872 then the kernel will not boot on CPUs that don't support PAE!
874 The actual amount of total physical memory will either be
875 auto detected or can be forced by using a kernel command line option
876 such as "mem=256M". (Try "man bootparam" or see the documentation of
877 your boot loader (lilo or loadlin) about how to pass options to the
878 kernel at boot time.)
880 If unsure, say "off".
884 depends on !X86_NUMAQ
886 Select this if you have a 32-bit processor and between 1 and 4
887 gigabytes of physical RAM.
891 depends on !M386 && !M486
894 Select this if you have a 32-bit processor and more than 4
895 gigabytes of physical RAM.
900 depends on EXPERIMENTAL
901 prompt "Memory split" if EMBEDDED
905 Select the desired split between kernel and user memory.
907 If the address range available to the kernel is less than the
908 physical memory installed, the remaining memory will be available
909 as "high memory". Accessing high memory is a little more costly
910 than low memory, as it needs to be mapped into the kernel first.
911 Note that increasing the kernel address space limits the range
912 available to user programs, making the address space there
913 tighter. Selecting anything other than the default 3G/1G split
914 will also likely make your kernel incompatible with binary-only
917 If you are not absolutely sure what you are doing, leave this
921 bool "3G/1G user/kernel split"
922 config VMSPLIT_3G_OPT
924 bool "3G/1G user/kernel split (for full 1G low memory)"
926 bool "2G/2G user/kernel split"
927 config VMSPLIT_2G_OPT
929 bool "2G/2G user/kernel split (for full 2G low memory)"
931 bool "1G/3G user/kernel split"
936 default 0xB0000000 if VMSPLIT_3G_OPT
937 default 0x80000000 if VMSPLIT_2G
938 default 0x78000000 if VMSPLIT_2G_OPT
939 default 0x40000000 if VMSPLIT_1G
945 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
949 prompt "PAE (Physical Address Extension) Support"
950 depends on X86_32 && !HIGHMEM4G
951 select RESOURCES_64BIT
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 # Common NUMA Features
960 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
962 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
964 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
966 Enable NUMA (Non Uniform Memory Access) support.
967 The kernel will try to allocate memory used by a CPU on the
968 local memory controller of the CPU and add some more
969 NUMA awareness to the kernel.
971 For 32-bit this is currently highly experimental and should be only
972 used for kernel development. It might also cause boot failures.
973 For 64-bit this is recommended on all multiprocessor Opteron systems.
974 If the system is EM64T, you should say N unless your system is
977 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
978 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
982 prompt "Old style AMD Opteron NUMA detection"
983 depends on X86_64 && NUMA && PCI
985 Enable K8 NUMA node topology detection. You should say Y here if
986 you have a multi processor AMD K8 system. This uses an old
987 method to read the NUMA configuration directly from the builtin
988 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
989 instead, which also takes priority if both are compiled in.
991 config X86_64_ACPI_NUMA
993 prompt "ACPI NUMA detection"
994 depends on X86_64 && NUMA && ACPI && PCI
997 Enable ACPI SRAT based node topology detection.
999 # Some NUMA nodes have memory ranges that span
1000 # other nodes. Even though a pfn is valid and
1001 # between a node's start and end pfns, it may not
1002 # reside on that node. See memmap_init_zone()
1004 config NODES_SPAN_OTHER_NODES
1006 depends on X86_64_ACPI_NUMA
1009 bool "NUMA emulation"
1010 depends on X86_64 && NUMA
1012 Enable NUMA emulation. A flat machine will be split
1013 into virtual nodes when booted with "numa=fake=N", where N is the
1014 number of nodes. This is only useful for debugging.
1017 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1019 default "9" if MAXSMP
1020 default "6" if X86_64
1021 default "4" if X86_NUMAQ
1023 depends on NEED_MULTIPLE_NODES
1025 Specify the maximum number of NUMA Nodes available on the target
1026 system. Increases memory reserved to accomodate various tables.
1028 config HAVE_ARCH_BOOTMEM_NODE
1030 depends on X86_32 && NUMA
1032 config ARCH_HAVE_MEMORY_PRESENT
1034 depends on X86_32 && DISCONTIGMEM
1036 config NEED_NODE_MEMMAP_SIZE
1038 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1040 config HAVE_ARCH_ALLOC_REMAP
1042 depends on X86_32 && NUMA
1044 config ARCH_FLATMEM_ENABLE
1046 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1048 config ARCH_DISCONTIGMEM_ENABLE
1050 depends on NUMA && X86_32
1052 config ARCH_DISCONTIGMEM_DEFAULT
1054 depends on NUMA && X86_32
1056 config ARCH_SPARSEMEM_DEFAULT
1060 config ARCH_SPARSEMEM_ENABLE
1062 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1063 select SPARSEMEM_STATIC if X86_32
1064 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1066 config ARCH_SELECT_MEMORY_MODEL
1068 depends on ARCH_SPARSEMEM_ENABLE
1070 config ARCH_MEMORY_PROBE
1072 depends on MEMORY_HOTPLUG
1077 bool "Allocate 3rd-level pagetables from highmem"
1078 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1080 The VM uses one page table entry for each page of physical memory.
1081 For systems with a lot of RAM, this can be wasteful of precious
1082 low memory. Setting this option will put user-space page table
1083 entries in high memory.
1085 config X86_CHECK_BIOS_CORRUPTION
1086 bool "Check for low memory corruption"
1088 Periodically check for memory corruption in low memory, which
1089 is suspected to be caused by BIOS. Even when enabled in the
1090 configuration, it is disabled at runtime. Enable it by
1091 setting "memory_corruption_check=1" on the kernel command
1092 line. By default it scans the low 64k of memory every 60
1093 seconds; see the memory_corruption_check_size and
1094 memory_corruption_check_period parameters in
1095 Documentation/kernel-parameters.txt to adjust this.
1097 When enabled with the default parameters, this option has
1098 almost no overhead, as it reserves a relatively small amount
1099 of memory and scans it infrequently. It both detects corruption
1100 and prevents it from affecting the running system.
1102 It is, however, intended as a diagnostic tool; if repeatable
1103 BIOS-originated corruption always affects the same memory,
1104 you can use memmap= to prevent the kernel from using that
1107 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1108 bool "Set the default setting of memory_corruption_check"
1109 depends on X86_CHECK_BIOS_CORRUPTION
1112 Set whether the default state of memory_corruption_check is
1115 config X86_RESERVE_LOW_64K
1116 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1119 Reserve the first 64K of physical RAM on BIOSes that are known
1120 to potentially corrupt that memory range. A numbers of BIOSes are
1121 known to utilize this area during suspend/resume, so it must not
1122 be used by the kernel.
1124 Set this to N if you are absolutely sure that you trust the BIOS
1125 to get all its memory reservations and usages right.
1127 If you have doubts about the BIOS (e.g. suspend/resume does not
1128 work or there's kernel crashes after certain hardware hotplug
1129 events) and it's not AMI or Phoenix, then you might want to enable
1130 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1131 corruption patterns.
1135 config MATH_EMULATION
1137 prompt "Math emulation" if X86_32
1139 Linux can emulate a math coprocessor (used for floating point
1140 operations) if you don't have one. 486DX and Pentium processors have
1141 a math coprocessor built in, 486SX and 386 do not, unless you added
1142 a 487DX or 387, respectively. (The messages during boot time can
1143 give you some hints here ["man dmesg"].) Everyone needs either a
1144 coprocessor or this emulation.
1146 If you don't have a math coprocessor, you need to say Y here; if you
1147 say Y here even though you have a coprocessor, the coprocessor will
1148 be used nevertheless. (This behavior can be changed with the kernel
1149 command line option "no387", which comes handy if your coprocessor
1150 is broken. Try "man bootparam" or see the documentation of your boot
1151 loader (lilo or loadlin) about how to pass options to the kernel at
1152 boot time.) This means that it is a good idea to say Y here if you
1153 intend to use this kernel on different machines.
1155 More information about the internals of the Linux math coprocessor
1156 emulation can be found in <file:arch/x86/math-emu/README>.
1158 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1159 kernel, it won't hurt.
1162 bool "MTRR (Memory Type Range Register) support"
1164 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1165 the Memory Type Range Registers (MTRRs) may be used to control
1166 processor access to memory ranges. This is most useful if you have
1167 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1168 allows bus write transfers to be combined into a larger transfer
1169 before bursting over the PCI/AGP bus. This can increase performance
1170 of image write operations 2.5 times or more. Saying Y here creates a
1171 /proc/mtrr file which may be used to manipulate your processor's
1172 MTRRs. Typically the X server should use this.
1174 This code has a reasonably generic interface so that similar
1175 control registers on other processors can be easily supported
1178 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1179 Registers (ARRs) which provide a similar functionality to MTRRs. For
1180 these, the ARRs are used to emulate the MTRRs.
1181 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1182 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1183 write-combining. All of these processors are supported by this code
1184 and it makes sense to say Y here if you have one of them.
1186 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1187 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1188 can lead to all sorts of problems, so it's good to say Y here.
1190 You can safely say Y even if your machine doesn't have MTRRs, you'll
1191 just add about 9 KB to your kernel.
1193 See <file:Documentation/x86/mtrr.txt> for more information.
1195 config MTRR_SANITIZER
1197 prompt "MTRR cleanup support"
1200 Convert MTRR layout from continuous to discrete, so X drivers can
1201 add writeback entries.
1203 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1204 The largest mtrr entry size for a continous block can be set with
1209 config MTRR_SANITIZER_ENABLE_DEFAULT
1210 int "MTRR cleanup enable value (0-1)"
1213 depends on MTRR_SANITIZER
1215 Enable mtrr cleanup default value
1217 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1218 int "MTRR cleanup spare reg num (0-7)"
1221 depends on MTRR_SANITIZER
1223 mtrr cleanup spare entries default, it can be changed via
1224 mtrr_spare_reg_nr=N on the kernel command line.
1228 prompt "x86 PAT support"
1231 Use PAT attributes to setup page level cache control.
1233 PATs are the modern equivalents of MTRRs and are much more
1234 flexible than MTRRs.
1236 Say N here if you see bootup problems (boot crash, boot hang,
1237 spontaneous reboots) or a non-working video driver.
1243 prompt "EFI runtime service support"
1246 This enables the kernel to use EFI runtime services that are
1247 available (such as the EFI variable services).
1249 This option is only useful on systems that have EFI firmware.
1250 In addition, you should use the latest ELILO loader available
1251 at <http://elilo.sourceforge.net> in order to take advantage
1252 of EFI runtime services. However, even with this option, the
1253 resultant kernel should continue to boot on existing non-EFI
1258 prompt "Enable seccomp to safely compute untrusted bytecode"
1260 This kernel feature is useful for number crunching applications
1261 that may need to compute untrusted bytecode during their
1262 execution. By using pipes or other transports made available to
1263 the process as file descriptors supporting the read/write
1264 syscalls, it's possible to isolate those applications in
1265 their own address space using seccomp. Once seccomp is
1266 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1267 and the task is only allowed to execute a few safe syscalls
1268 defined by each seccomp mode.
1270 If unsure, say Y. Only embedded should say N here.
1272 config CC_STACKPROTECTOR
1273 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1274 depends on X86_64 && EXPERIMENTAL && BROKEN
1276 This option turns on the -fstack-protector GCC feature. This
1277 feature puts, at the beginning of critical functions, a canary
1278 value on the stack just before the return address, and validates
1279 the value just before actually returning. Stack based buffer
1280 overflows (that need to overwrite this return address) now also
1281 overwrite the canary, which gets detected and the attack is then
1282 neutralized via a kernel panic.
1284 This feature requires gcc version 4.2 or above, or a distribution
1285 gcc with the feature backported. Older versions are automatically
1286 detected and for those versions, this configuration option is ignored.
1288 config CC_STACKPROTECTOR_ALL
1289 bool "Use stack-protector for all functions"
1290 depends on CC_STACKPROTECTOR
1292 Normally, GCC only inserts the canary value protection for
1293 functions that use large-ish on-stack buffers. By enabling
1294 this option, GCC will be asked to do this for ALL functions.
1296 source kernel/Kconfig.hz
1299 bool "kexec system call"
1300 depends on X86_BIOS_REBOOT
1302 kexec is a system call that implements the ability to shutdown your
1303 current kernel, and to start another kernel. It is like a reboot
1304 but it is independent of the system firmware. And like a reboot
1305 you can start any kernel with it, not just Linux.
1307 The name comes from the similarity to the exec system call.
1309 It is an ongoing process to be certain the hardware in a machine
1310 is properly shutdown, so do not be surprised if this code does not
1311 initially work for you. It may help to enable device hotplugging
1312 support. As of this writing the exact hardware interface is
1313 strongly in flux, so no good recommendation can be made.
1316 bool "kernel crash dumps"
1317 depends on X86_64 || (X86_32 && HIGHMEM)
1319 Generate crash dump after being started by kexec.
1320 This should be normally only set in special crash dump kernels
1321 which are loaded in the main kernel with kexec-tools into
1322 a specially reserved region and then later executed after
1323 a crash by kdump/kexec. The crash dump kernel must be compiled
1324 to a memory address not used by the main kernel or BIOS using
1325 PHYSICAL_START, or it must be built as a relocatable image
1326 (CONFIG_RELOCATABLE=y).
1327 For more details see Documentation/kdump/kdump.txt
1330 bool "kexec jump (EXPERIMENTAL)"
1331 depends on EXPERIMENTAL
1332 depends on KEXEC && HIBERNATION && X86_32
1334 Jump between original kernel and kexeced kernel and invoke
1335 code in physical address mode via KEXEC
1337 config PHYSICAL_START
1338 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1339 default "0x1000000" if X86_NUMAQ
1340 default "0x200000" if X86_64
1343 This gives the physical address where the kernel is loaded.
1345 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1346 bzImage will decompress itself to above physical address and
1347 run from there. Otherwise, bzImage will run from the address where
1348 it has been loaded by the boot loader and will ignore above physical
1351 In normal kdump cases one does not have to set/change this option
1352 as now bzImage can be compiled as a completely relocatable image
1353 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1354 address. This option is mainly useful for the folks who don't want
1355 to use a bzImage for capturing the crash dump and want to use a
1356 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1357 to be specifically compiled to run from a specific memory area
1358 (normally a reserved region) and this option comes handy.
1360 So if you are using bzImage for capturing the crash dump, leave
1361 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1362 Otherwise if you plan to use vmlinux for capturing the crash dump
1363 change this value to start of the reserved region (Typically 16MB
1364 0x1000000). In other words, it can be set based on the "X" value as
1365 specified in the "crashkernel=YM@XM" command line boot parameter
1366 passed to the panic-ed kernel. Typically this parameter is set as
1367 crashkernel=64M@16M. Please take a look at
1368 Documentation/kdump/kdump.txt for more details about crash dumps.
1370 Usage of bzImage for capturing the crash dump is recommended as
1371 one does not have to build two kernels. Same kernel can be used
1372 as production kernel and capture kernel. Above option should have
1373 gone away after relocatable bzImage support is introduced. But it
1374 is present because there are users out there who continue to use
1375 vmlinux for dump capture. This option should go away down the
1378 Don't change this unless you know what you are doing.
1381 bool "Build a relocatable kernel (EXPERIMENTAL)"
1382 depends on EXPERIMENTAL
1384 This builds a kernel image that retains relocation information
1385 so it can be loaded someplace besides the default 1MB.
1386 The relocations tend to make the kernel binary about 10% larger,
1387 but are discarded at runtime.
1389 One use is for the kexec on panic case where the recovery kernel
1390 must live at a different physical address than the primary
1393 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1394 it has been loaded at and the compile time physical address
1395 (CONFIG_PHYSICAL_START) is ignored.
1397 config PHYSICAL_ALIGN
1399 prompt "Alignment value to which kernel should be aligned" if X86_32
1400 default "0x100000" if X86_32
1401 default "0x200000" if X86_64
1402 range 0x2000 0x400000
1404 This value puts the alignment restrictions on physical address
1405 where kernel is loaded and run from. Kernel is compiled for an
1406 address which meets above alignment restriction.
1408 If bootloader loads the kernel at a non-aligned address and
1409 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1410 address aligned to above value and run from there.
1412 If bootloader loads the kernel at a non-aligned address and
1413 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1414 load address and decompress itself to the address it has been
1415 compiled for and run from there. The address for which kernel is
1416 compiled already meets above alignment restrictions. Hence the
1417 end result is that kernel runs from a physical address meeting
1418 above alignment restrictions.
1420 Don't change this unless you know what you are doing.
1423 bool "Support for hot-pluggable CPUs"
1424 depends on SMP && HOTPLUG && !X86_VOYAGER
1426 Say Y here to allow turning CPUs off and on. CPUs can be
1427 controlled through /sys/devices/system/cpu.
1428 ( Note: power management support will enable this option
1429 automatically on SMP systems. )
1430 Say N if you want to disable CPU hotplug.
1434 prompt "Compat VDSO support"
1435 depends on X86_32 || IA32_EMULATION
1437 Map the 32-bit VDSO to the predictable old-style address too.
1439 Say N here if you are running a sufficiently recent glibc
1440 version (2.3.3 or later), to remove the high-mapped
1441 VDSO mapping and to exclusively use the randomized VDSO.
1446 bool "Built-in kernel command line"
1449 Allow for specifying boot arguments to the kernel at
1450 build time. On some systems (e.g. embedded ones), it is
1451 necessary or convenient to provide some or all of the
1452 kernel boot arguments with the kernel itself (that is,
1453 to not rely on the boot loader to provide them.)
1455 To compile command line arguments into the kernel,
1456 set this option to 'Y', then fill in the
1457 the boot arguments in CONFIG_CMDLINE.
1459 Systems with fully functional boot loaders (i.e. non-embedded)
1460 should leave this option set to 'N'.
1463 string "Built-in kernel command string"
1464 depends on CMDLINE_BOOL
1467 Enter arguments here that should be compiled into the kernel
1468 image and used at boot time. If the boot loader provides a
1469 command line at boot time, it is appended to this string to
1470 form the full kernel command line, when the system boots.
1472 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1473 change this behavior.
1475 In most cases, the command line (whether built-in or provided
1476 by the boot loader) should specify the device for the root
1479 config CMDLINE_OVERRIDE
1480 bool "Built-in command line overrides boot loader arguments"
1482 depends on CMDLINE_BOOL
1484 Set this option to 'Y' to have the kernel ignore the boot loader
1485 command line, and use ONLY the built-in command line.
1487 This is used to work around broken boot loaders. This should
1488 be set to 'N' under normal conditions.
1492 config ARCH_ENABLE_MEMORY_HOTPLUG
1494 depends on X86_64 || (X86_32 && HIGHMEM)
1496 config HAVE_ARCH_EARLY_PFN_TO_NID
1500 menu "Power management options"
1501 depends on !X86_VOYAGER
1503 config ARCH_HIBERNATION_HEADER
1505 depends on X86_64 && HIBERNATION
1507 source "kernel/power/Kconfig"
1509 source "drivers/acpi/Kconfig"
1514 depends on APM || APM_MODULE
1517 tristate "APM (Advanced Power Management) BIOS support"
1518 depends on X86_32 && PM_SLEEP
1520 APM is a BIOS specification for saving power using several different
1521 techniques. This is mostly useful for battery powered laptops with
1522 APM compliant BIOSes. If you say Y here, the system time will be
1523 reset after a RESUME operation, the /proc/apm device will provide
1524 battery status information, and user-space programs will receive
1525 notification of APM "events" (e.g. battery status change).
1527 If you select "Y" here, you can disable actual use of the APM
1528 BIOS by passing the "apm=off" option to the kernel at boot time.
1530 Note that the APM support is almost completely disabled for
1531 machines with more than one CPU.
1533 In order to use APM, you will need supporting software. For location
1534 and more information, read <file:Documentation/power/pm.txt> and the
1535 Battery Powered Linux mini-HOWTO, available from
1536 <http://www.tldp.org/docs.html#howto>.
1538 This driver does not spin down disk drives (see the hdparm(8)
1539 manpage ("man 8 hdparm") for that), and it doesn't turn off
1540 VESA-compliant "green" monitors.
1542 This driver does not support the TI 4000M TravelMate and the ACER
1543 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1544 desktop machines also don't have compliant BIOSes, and this driver
1545 may cause those machines to panic during the boot phase.
1547 Generally, if you don't have a battery in your machine, there isn't
1548 much point in using this driver and you should say N. If you get
1549 random kernel OOPSes or reboots that don't seem to be related to
1550 anything, try disabling/enabling this option (or disabling/enabling
1553 Some other things you should try when experiencing seemingly random,
1556 1) make sure that you have enough swap space and that it is
1558 2) pass the "no-hlt" option to the kernel
1559 3) switch on floating point emulation in the kernel and pass
1560 the "no387" option to the kernel
1561 4) pass the "floppy=nodma" option to the kernel
1562 5) pass the "mem=4M" option to the kernel (thereby disabling
1563 all but the first 4 MB of RAM)
1564 6) make sure that the CPU is not over clocked.
1565 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1566 8) disable the cache from your BIOS settings
1567 9) install a fan for the video card or exchange video RAM
1568 10) install a better fan for the CPU
1569 11) exchange RAM chips
1570 12) exchange the motherboard.
1572 To compile this driver as a module, choose M here: the
1573 module will be called apm.
1577 config APM_IGNORE_USER_SUSPEND
1578 bool "Ignore USER SUSPEND"
1580 This option will ignore USER SUSPEND requests. On machines with a
1581 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1582 series notebooks, it is necessary to say Y because of a BIOS bug.
1584 config APM_DO_ENABLE
1585 bool "Enable PM at boot time"
1587 Enable APM features at boot time. From page 36 of the APM BIOS
1588 specification: "When disabled, the APM BIOS does not automatically
1589 power manage devices, enter the Standby State, enter the Suspend
1590 State, or take power saving steps in response to CPU Idle calls."
1591 This driver will make CPU Idle calls when Linux is idle (unless this
1592 feature is turned off -- see "Do CPU IDLE calls", below). This
1593 should always save battery power, but more complicated APM features
1594 will be dependent on your BIOS implementation. You may need to turn
1595 this option off if your computer hangs at boot time when using APM
1596 support, or if it beeps continuously instead of suspending. Turn
1597 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1598 T400CDT. This is off by default since most machines do fine without
1602 bool "Make CPU Idle calls when idle"
1604 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1605 On some machines, this can activate improved power savings, such as
1606 a slowed CPU clock rate, when the machine is idle. These idle calls
1607 are made after the idle loop has run for some length of time (e.g.,
1608 333 mS). On some machines, this will cause a hang at boot time or
1609 whenever the CPU becomes idle. (On machines with more than one CPU,
1610 this option does nothing.)
1612 config APM_DISPLAY_BLANK
1613 bool "Enable console blanking using APM"
1615 Enable console blanking using the APM. Some laptops can use this to
1616 turn off the LCD backlight when the screen blanker of the Linux
1617 virtual console blanks the screen. Note that this is only used by
1618 the virtual console screen blanker, and won't turn off the backlight
1619 when using the X Window system. This also doesn't have anything to
1620 do with your VESA-compliant power-saving monitor. Further, this
1621 option doesn't work for all laptops -- it might not turn off your
1622 backlight at all, or it might print a lot of errors to the console,
1623 especially if you are using gpm.
1625 config APM_ALLOW_INTS
1626 bool "Allow interrupts during APM BIOS calls"
1628 Normally we disable external interrupts while we are making calls to
1629 the APM BIOS as a measure to lessen the effects of a badly behaving
1630 BIOS implementation. The BIOS should reenable interrupts if it
1631 needs to. Unfortunately, some BIOSes do not -- especially those in
1632 many of the newer IBM Thinkpads. If you experience hangs when you
1633 suspend, try setting this to Y. Otherwise, say N.
1635 config APM_REAL_MODE_POWER_OFF
1636 bool "Use real mode APM BIOS call to power off"
1638 Use real mode APM BIOS calls to switch off the computer. This is
1639 a work-around for a number of buggy BIOSes. Switch this option on if
1640 your computer crashes instead of powering off properly.
1644 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1646 source "drivers/cpuidle/Kconfig"
1651 menu "Bus options (PCI etc.)"
1656 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1658 Find out whether you have a PCI motherboard. PCI is the name of a
1659 bus system, i.e. the way the CPU talks to the other stuff inside
1660 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1661 VESA. If you have PCI, say Y, otherwise N.
1664 prompt "PCI access mode"
1665 depends on X86_32 && PCI
1668 On PCI systems, the BIOS can be used to detect the PCI devices and
1669 determine their configuration. However, some old PCI motherboards
1670 have BIOS bugs and may crash if this is done. Also, some embedded
1671 PCI-based systems don't have any BIOS at all. Linux can also try to
1672 detect the PCI hardware directly without using the BIOS.
1674 With this option, you can specify how Linux should detect the
1675 PCI devices. If you choose "BIOS", the BIOS will be used,
1676 if you choose "Direct", the BIOS won't be used, and if you
1677 choose "MMConfig", then PCI Express MMCONFIG will be used.
1678 If you choose "Any", the kernel will try MMCONFIG, then the
1679 direct access method and falls back to the BIOS if that doesn't
1680 work. If unsure, go with the default, which is "Any".
1685 config PCI_GOMMCONFIG
1702 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1704 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1707 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1711 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1715 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1722 bool "Support mmconfig PCI config space access"
1723 depends on X86_64 && PCI && ACPI
1726 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1727 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1729 DMA remapping (DMAR) devices support enables independent address
1730 translations for Direct Memory Access (DMA) from devices.
1731 These DMA remapping devices are reported via ACPI tables
1732 and include PCI device scope covered by these DMA
1737 prompt "Support for Graphics workaround"
1740 Current Graphics drivers tend to use physical address
1741 for DMA and avoid using DMA APIs. Setting this config
1742 option permits the IOMMU driver to set a unity map for
1743 all the OS-visible memory. Hence the driver can continue
1744 to use physical addresses for DMA.
1746 config DMAR_FLOPPY_WA
1750 Floppy disk drivers are know to bypass DMA API calls
1751 thereby failing to work when IOMMU is enabled. This
1752 workaround will setup a 1:1 mapping for the first
1753 16M to make floppy (an ISA device) work.
1756 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1757 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1759 Supports Interrupt remapping for IO-APIC and MSI devices.
1760 To use x2apic mode in the CPU's which support x2APIC enhancements or
1761 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1763 source "drivers/pci/pcie/Kconfig"
1765 source "drivers/pci/Kconfig"
1767 # x86_64 have no ISA slots, but do have ISA-style DMA.
1775 depends on !X86_VOYAGER
1777 Find out whether you have ISA slots on your motherboard. ISA is the
1778 name of a bus system, i.e. the way the CPU talks to the other stuff
1779 inside your box. Other bus systems are PCI, EISA, MicroChannel
1780 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1781 newer boards don't support it. If you have ISA, say Y, otherwise N.
1787 The Extended Industry Standard Architecture (EISA) bus was
1788 developed as an open alternative to the IBM MicroChannel bus.
1790 The EISA bus provided some of the features of the IBM MicroChannel
1791 bus while maintaining backward compatibility with cards made for
1792 the older ISA bus. The EISA bus saw limited use between 1988 and
1793 1995 when it was made obsolete by the PCI bus.
1795 Say Y here if you are building a kernel for an EISA-based machine.
1799 source "drivers/eisa/Kconfig"
1802 bool "MCA support" if !X86_VOYAGER
1803 default y if X86_VOYAGER
1805 MicroChannel Architecture is found in some IBM PS/2 machines and
1806 laptops. It is a bus system similar to PCI or ISA. See
1807 <file:Documentation/mca.txt> (and especially the web page given
1808 there) before attempting to build an MCA bus kernel.
1810 source "drivers/mca/Kconfig"
1813 tristate "NatSemi SCx200 support"
1814 depends on !X86_VOYAGER
1816 This provides basic support for National Semiconductor's
1817 (now AMD's) Geode processors. The driver probes for the
1818 PCI-IDs of several on-chip devices, so its a good dependency
1819 for other scx200_* drivers.
1821 If compiled as a module, the driver is named scx200.
1823 config SCx200HR_TIMER
1824 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1825 depends on SCx200 && GENERIC_TIME
1828 This driver provides a clocksource built upon the on-chip
1829 27MHz high-resolution timer. Its also a workaround for
1830 NSC Geode SC-1100's buggy TSC, which loses time when the
1831 processor goes idle (as is done by the scheduler). The
1832 other workaround is idle=poll boot option.
1834 config GEODE_MFGPT_TIMER
1836 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1837 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1839 This driver provides a clock event source based on the MFGPT
1840 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1841 MFGPTs have a better resolution and max interval than the
1842 generic PIT, and are suitable for use as high-res timers.
1845 bool "One Laptop Per Child support"
1848 Add support for detecting the unique features of the OLPC
1855 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1857 source "drivers/pcmcia/Kconfig"
1859 source "drivers/pci/hotplug/Kconfig"
1864 menu "Executable file formats / Emulations"
1866 source "fs/Kconfig.binfmt"
1868 config IA32_EMULATION
1869 bool "IA32 Emulation"
1871 select COMPAT_BINFMT_ELF
1873 Include code to run 32-bit programs under a 64-bit kernel. You should
1874 likely turn this on, unless you're 100% sure that you don't have any
1875 32-bit programs left.
1878 tristate "IA32 a.out support"
1879 depends on IA32_EMULATION
1881 Support old a.out binaries in the 32bit emulation.
1885 depends on IA32_EMULATION
1887 config COMPAT_FOR_U64_ALIGNMENT
1891 config SYSVIPC_COMPAT
1893 depends on COMPAT && SYSVIPC
1898 source "net/Kconfig"
1900 source "drivers/Kconfig"
1902 source "drivers/firmware/Kconfig"
1906 source "arch/x86/Kconfig.debug"
1908 source "security/Kconfig"
1910 source "crypto/Kconfig"
1912 source "arch/x86/kvm/Kconfig"
1914 source "lib/Kconfig"
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