2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
22 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IOREMAP_PROT
27 select ARCH_WANT_OPTIONAL_GPIOLIB
28 select HAVE_KRETPROBES
29 select HAVE_FTRACE_MCOUNT_RECORD
30 select HAVE_DYNAMIC_FTRACE
32 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
33 select HAVE_ARCH_KGDB if !X86_VOYAGER
34 select HAVE_ARCH_TRACEHOOK
35 select HAVE_GENERIC_DMA_COHERENT if X86_32
36 select HAVE_EFFICIENT_UNALIGNED_ACCESS
40 default "arch/x86/configs/i386_defconfig" if X86_32
41 default "arch/x86/configs/x86_64_defconfig" if X86_64
46 config GENERIC_CMOS_UPDATE
49 config CLOCKSOURCE_WATCHDOG
52 config GENERIC_CLOCKEVENTS
55 config GENERIC_CLOCKEVENTS_BROADCAST
57 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
59 config LOCKDEP_SUPPORT
62 config STACKTRACE_SUPPORT
65 config HAVE_LATENCYTOP_SUPPORT
68 config FAST_CMPXCHG_LOCAL
81 config GENERIC_ISA_DMA
91 config GENERIC_HWEIGHT
97 config ARCH_MAY_HAVE_PC_FDC
100 config RWSEM_GENERIC_SPINLOCK
103 config RWSEM_XCHGADD_ALGORITHM
106 config ARCH_HAS_CPU_IDLE_WAIT
109 config GENERIC_CALIBRATE_DELAY
112 config GENERIC_TIME_VSYSCALL
116 config ARCH_HAS_CPU_RELAX
119 config ARCH_HAS_DEFAULT_IDLE
122 config ARCH_HAS_CACHE_LINE_SIZE
125 config HAVE_SETUP_PER_CPU_AREA
126 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
128 config HAVE_CPUMASK_OF_CPU_MAP
131 config ARCH_HIBERNATION_POSSIBLE
133 depends on !SMP || !X86_VOYAGER
135 config ARCH_SUSPEND_POSSIBLE
137 depends on !X86_VOYAGER
143 config ARCH_POPULATES_NODE_MAP
150 config ARCH_SUPPORTS_OPTIMIZED_INLINING
153 # Use the generic interrupt handling code in kernel/irq/:
154 config GENERIC_HARDIRQS
158 config GENERIC_IRQ_PROBE
162 config GENERIC_PENDING_IRQ
164 depends on GENERIC_HARDIRQS && SMP
169 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
170 select USE_GENERIC_SMP_HELPERS
175 depends on X86_32 && SMP
179 depends on X86_64 && SMP
184 depends on (X86_32 && !X86_VOYAGER) || X86_64
187 config X86_BIOS_REBOOT
189 depends on !X86_VOYAGER
192 config X86_TRAMPOLINE
194 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
199 source "init/Kconfig"
200 source "kernel/Kconfig.freezer"
202 menu "Processor type and features"
204 source "kernel/time/Kconfig"
207 bool "Symmetric multi-processing support"
209 This enables support for systems with more than one CPU. If you have
210 a system with only one CPU, like most personal computers, say N. If
211 you have a system with more than one CPU, say Y.
213 If you say N here, the kernel will run on single and multiprocessor
214 machines, but will use only one CPU of a multiprocessor machine. If
215 you say Y here, the kernel will run on many, but not all,
216 singleprocessor machines. On a singleprocessor machine, the kernel
217 will run faster if you say N here.
219 Note that if you say Y here and choose architecture "586" or
220 "Pentium" under "Processor family", the kernel will not work on 486
221 architectures. Similarly, multiprocessor kernels for the "PPro"
222 architecture may not work on all Pentium based boards.
224 People using multiprocessor machines who say Y here should also say
225 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
226 Management" code will be disabled if you say Y here.
228 See also <file:Documentation/i386/IO-APIC.txt>,
229 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
230 <http://www.tldp.org/docs.html#howto>.
232 If you don't know what to do here, say N.
234 config X86_FIND_SMP_CONFIG
236 depends on X86_MPPARSE || X86_VOYAGER
239 bool "Enable MPS table" if ACPI
241 depends on X86_LOCAL_APIC
243 For old smp systems that do not have proper acpi support. Newer systems
244 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
247 prompt "Subarchitecture Type"
253 Choose this option if your computer is a standard PC or compatible.
259 Select this for an AMD Elan processor.
261 Do not use this option for K6/Athlon/Opteron processors!
263 If unsure, choose "PC-compatible" instead.
267 depends on X86_32 && (SMP || BROKEN) && !PCI
269 Voyager is an MCA-based 32-way capable SMP architecture proprietary
270 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
274 If you do not specifically know you have a Voyager based machine,
275 say N here, otherwise the kernel you build will not be bootable.
277 config X86_GENERICARCH
278 bool "Generic architecture"
281 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
282 subarchitectures. It is intended for a generic binary kernel.
283 if you select them all, kernel will probe it one by one. and will
289 bool "NUMAQ (IBM/Sequent)"
290 depends on SMP && X86_32 && PCI && X86_MPPARSE
293 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
294 NUMA multiquad box. This changes the way that processors are
295 bootstrapped, and uses Clustered Logical APIC addressing mode instead
296 of Flat Logical. You will need a new lynxer.elf file to flash your
297 firmware with - send email to <Martin.Bligh@us.ibm.com>.
300 bool "Summit/EXA (IBM x440)"
301 depends on X86_32 && SMP
303 This option is needed for IBM systems that use the Summit/EXA chipset.
304 In particular, it is needed for the x440.
307 bool "Support for Unisys ES7000 IA32 series"
308 depends on X86_32 && SMP
310 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
311 supposed to run on an IA32-based Unisys ES7000 system.
314 bool "Support for big SMP systems with more than 8 CPUs"
315 depends on X86_32 && SMP
317 This option is needed for the systems that have more than 8 CPUs
318 and if the system is not of any sub-arch type above.
323 bool "Support for ScaleMP vSMP"
325 depends on X86_64 && PCI
327 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
328 supposed to run on these EM64T-based machines. Only choose this option
329 if you have one of these machines.
334 bool "SGI 320/540 (Visual Workstation)"
335 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
337 The SGI Visual Workstation series is an IA32-based workstation
338 based on SGI systems chips with some legacy PC hardware attached.
340 Say Y here to create a kernel to run on the SGI 320 or 540.
342 A kernel compiled for the Visual Workstation will run on general
343 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
346 bool "RDC R-321x SoC"
349 select X86_REBOOTFIXUPS
351 This option is needed for RDC R-321x system-on-chip, also known
353 If you don't have one of these chips, you should say N here.
355 config SCHED_NO_NO_OMIT_FRAME_POINTER
357 prompt "Single-depth WCHAN output"
360 Calculate simpler /proc/<PID>/wchan values. If this option
361 is disabled then wchan values will recurse back to the
362 caller function. This provides more accurate wchan values,
363 at the expense of slightly more scheduling overhead.
365 If in doubt, say "Y".
367 menuconfig PARAVIRT_GUEST
368 bool "Paravirtualized guest support"
370 Say Y here to get to see options related to running Linux under
371 various hypervisors. This option alone does not add any kernel code.
373 If you say N, all options in this submenu will be skipped and disabled.
377 source "arch/x86/xen/Kconfig"
380 bool "VMI Guest support"
383 depends on !X86_VOYAGER
385 VMI provides a paravirtualized interface to the VMware ESX server
386 (it could be used by other hypervisors in theory too, but is not
387 at the moment), by linking the kernel to a GPL-ed ROM module
388 provided by the hypervisor.
391 bool "KVM paravirtualized clock"
393 select PARAVIRT_CLOCK
394 depends on !X86_VOYAGER
396 Turning on this option will allow you to run a paravirtualized clock
397 when running over the KVM hypervisor. Instead of relying on a PIT
398 (or probably other) emulation by the underlying device model, the host
399 provides the guest with timing infrastructure such as time of day, and
403 bool "KVM Guest support"
405 depends on !X86_VOYAGER
407 This option enables various optimizations for running under the KVM
410 source "arch/x86/lguest/Kconfig"
413 bool "Enable paravirtualization code"
414 depends on !X86_VOYAGER
416 This changes the kernel so it can modify itself when it is run
417 under a hypervisor, potentially improving performance significantly
418 over full virtualization. However, when run without a hypervisor
419 the kernel is theoretically slower and slightly larger.
421 config PARAVIRT_CLOCK
427 config PARAVIRT_DEBUG
428 bool "paravirt-ops debugging"
429 depends on PARAVIRT && DEBUG_KERNEL
431 Enable to debug paravirt_ops internals. Specifically, BUG if
432 a paravirt_op is missing when it is called.
437 This option adds a kernel parameter 'memtest', which allows memtest
439 memtest=0, mean disabled; -- default
440 memtest=1, mean do 1 test pattern;
442 memtest=4, mean do 4 test patterns.
443 If you are unsure how to answer this question, answer N.
445 config X86_SUMMIT_NUMA
447 depends on X86_32 && NUMA && X86_GENERICARCH
449 config X86_CYCLONE_TIMER
451 depends on X86_GENERICARCH
453 config ES7000_CLUSTERED_APIC
455 depends on SMP && X86_ES7000 && MPENTIUMIII
457 source "arch/x86/Kconfig.cpu"
461 prompt "HPET Timer Support" if X86_32
463 Use the IA-PC HPET (High Precision Event Timer) to manage
464 time in preference to the PIT and RTC, if a HPET is
466 HPET is the next generation timer replacing legacy 8254s.
467 The HPET provides a stable time base on SMP
468 systems, unlike the TSC, but it is more expensive to access,
469 as it is off-chip. You can find the HPET spec at
470 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
472 You can safely choose Y here. However, HPET will only be
473 activated if the platform and the BIOS support this feature.
474 Otherwise the 8254 will be used for timing services.
476 Choose N to continue using the legacy 8254 timer.
478 config HPET_EMULATE_RTC
480 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
482 # Mark as embedded because too many people got it wrong.
483 # The code disables itself when not needed.
486 bool "Enable DMI scanning" if EMBEDDED
488 Enabled scanning of DMI to identify machine quirks. Say Y
489 here unless you have verified that your setup is not
490 affected by entries in the DMI blacklist. Required by PNP
494 bool "GART IOMMU support" if EMBEDDED
498 depends on X86_64 && PCI
500 Support for full DMA access of devices with 32bit memory access only
501 on systems with more than 3GB. This is usually needed for USB,
502 sound, many IDE/SATA chipsets and some other devices.
503 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
504 based hardware IOMMU and a software bounce buffer based IOMMU used
505 on Intel systems and as fallback.
506 The code is only active when needed (enough memory and limited
507 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
511 bool "IBM Calgary IOMMU support"
513 depends on X86_64 && PCI && EXPERIMENTAL
515 Support for hardware IOMMUs in IBM's xSeries x366 and x460
516 systems. Needed to run systems with more than 3GB of memory
517 properly with 32-bit PCI devices that do not support DAC
518 (Double Address Cycle). Calgary also supports bus level
519 isolation, where all DMAs pass through the IOMMU. This
520 prevents them from going anywhere except their intended
521 destination. This catches hard-to-find kernel bugs and
522 mis-behaving drivers and devices that do not use the DMA-API
523 properly to set up their DMA buffers. The IOMMU can be
524 turned off at boot time with the iommu=off parameter.
525 Normally the kernel will make the right choice by itself.
528 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
530 prompt "Should Calgary be enabled by default?"
531 depends on CALGARY_IOMMU
533 Should Calgary be enabled by default? if you choose 'y', Calgary
534 will be used (if it exists). If you choose 'n', Calgary will not be
535 used even if it exists. If you choose 'n' and would like to use
536 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
540 bool "AMD IOMMU support"
543 depends on X86_64 && PCI && ACPI
545 With this option you can enable support for AMD IOMMU hardware in
546 your system. An IOMMU is a hardware component which provides
547 remapping of DMA memory accesses from devices. With an AMD IOMMU you
548 can isolate the the DMA memory of different devices and protect the
549 system from misbehaving device drivers or hardware.
551 You can find out if your system has an AMD IOMMU if you look into
552 your BIOS for an option to enable it or if you have an IVRS ACPI
555 # need this always selected by IOMMU for the VIA workaround
559 Support for software bounce buffers used on x86-64 systems
560 which don't have a hardware IOMMU (e.g. the current generation
561 of Intel's x86-64 CPUs). Using this PCI devices which can only
562 access 32-bits of memory can be used on systems with more than
563 3 GB of memory. If unsure, say Y.
566 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
569 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
570 depends on X86_64 && SMP && BROKEN
573 Configure maximum number of CPUS and NUMA Nodes for this architecture.
577 int "Maximum number of CPUs (2-512)" if !MAXSMP
580 default "4096" if MAXSMP
581 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
584 This allows you to specify the maximum number of CPUs which this
585 kernel will support. The maximum supported value is 512 and the
586 minimum value which makes sense is 2.
588 This is purely to save memory - each supported CPU adds
589 approximately eight kilobytes to the kernel image.
592 bool "SMT (Hyperthreading) scheduler support"
595 SMT scheduler support improves the CPU scheduler's decision making
596 when dealing with Intel Pentium 4 chips with HyperThreading at a
597 cost of slightly increased overhead in some places. If unsure say
602 prompt "Multi-core scheduler support"
605 Multi-core scheduler support improves the CPU scheduler's decision
606 making when dealing with multi-core CPU chips at a cost of slightly
607 increased overhead in some places. If unsure say N here.
609 source "kernel/Kconfig.preempt"
612 bool "Local APIC support on uniprocessors"
613 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
615 A local APIC (Advanced Programmable Interrupt Controller) is an
616 integrated interrupt controller in the CPU. If you have a single-CPU
617 system which has a processor with a local APIC, you can say Y here to
618 enable and use it. If you say Y here even though your machine doesn't
619 have a local APIC, then the kernel will still run with no slowdown at
620 all. The local APIC supports CPU-generated self-interrupts (timer,
621 performance counters), and the NMI watchdog which detects hard
625 bool "IO-APIC support on uniprocessors"
626 depends on X86_UP_APIC
628 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
629 SMP-capable replacement for PC-style interrupt controllers. Most
630 SMP systems and many recent uniprocessor systems have one.
632 If you have a single-CPU system with an IO-APIC, you can say Y here
633 to use it. If you say Y here even though your machine doesn't have
634 an IO-APIC, then the kernel will still run with no slowdown at all.
636 config X86_LOCAL_APIC
638 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
642 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
644 config X86_VISWS_APIC
646 depends on X86_32 && X86_VISWS
649 bool "Machine Check Exception"
650 depends on !X86_VOYAGER
652 Machine Check Exception support allows the processor to notify the
653 kernel if it detects a problem (e.g. overheating, component failure).
654 The action the kernel takes depends on the severity of the problem,
655 ranging from a warning message on the console, to halting the machine.
656 Your processor must be a Pentium or newer to support this - check the
657 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
658 have a design flaw which leads to false MCE events - hence MCE is
659 disabled on all P5 processors, unless explicitly enabled with "mce"
660 as a boot argument. Similarly, if MCE is built in and creates a
661 problem on some new non-standard machine, you can boot with "nomce"
662 to disable it. MCE support simply ignores non-MCE processors like
663 the 386 and 486, so nearly everyone can say Y here.
667 prompt "Intel MCE features"
668 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
670 Additional support for intel specific MCE features such as
675 prompt "AMD MCE features"
676 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
678 Additional support for AMD specific MCE features such as
679 the DRAM Error Threshold.
681 config X86_MCE_NONFATAL
682 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
683 depends on X86_32 && X86_MCE
685 Enabling this feature starts a timer that triggers every 5 seconds which
686 will look at the machine check registers to see if anything happened.
687 Non-fatal problems automatically get corrected (but still logged).
688 Disable this if you don't want to see these messages.
689 Seeing the messages this option prints out may be indicative of dying
690 or out-of-spec (ie, overclocked) hardware.
691 This option only does something on certain CPUs.
692 (AMD Athlon/Duron and Intel Pentium 4)
694 config X86_MCE_P4THERMAL
695 bool "check for P4 thermal throttling interrupt."
696 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
698 Enabling this feature will cause a message to be printed when the P4
699 enters thermal throttling.
702 bool "Enable VM86 support" if EMBEDDED
706 This option is required by programs like DOSEMU to run 16-bit legacy
707 code on X86 processors. It also may be needed by software like
708 XFree86 to initialize some video cards via BIOS. Disabling this
709 option saves about 6k.
712 tristate "Toshiba Laptop support"
715 This adds a driver to safely access the System Management Mode of
716 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
717 not work on models with a Phoenix BIOS. The System Management Mode
718 is used to set the BIOS and power saving options on Toshiba portables.
720 For information on utilities to make use of this driver see the
721 Toshiba Linux utilities web site at:
722 <http://www.buzzard.org.uk/toshiba/>.
724 Say Y if you intend to run this kernel on a Toshiba portable.
728 tristate "Dell laptop support"
730 This adds a driver to safely access the System Management Mode
731 of the CPU on the Dell Inspiron 8000. The System Management Mode
732 is used to read cpu temperature and cooling fan status and to
733 control the fans on the I8K portables.
735 This driver has been tested only on the Inspiron 8000 but it may
736 also work with other Dell laptops. You can force loading on other
737 models by passing the parameter `force=1' to the module. Use at
740 For information on utilities to make use of this driver see the
741 I8K Linux utilities web site at:
742 <http://people.debian.org/~dz/i8k/>
744 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
747 config X86_REBOOTFIXUPS
748 bool "Enable X86 board specific fixups for reboot"
751 This enables chipset and/or board specific fixups to be done
752 in order to get reboot to work correctly. This is only needed on
753 some combinations of hardware and BIOS. The symptom, for which
754 this config is intended, is when reboot ends with a stalled/hung
757 Currently, the only fixup is for the Geode machines using
758 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
760 Say Y if you want to enable the fixup. Currently, it's safe to
761 enable this option even if you don't need it.
765 tristate "/dev/cpu/microcode - microcode support"
768 If you say Y here, you will be able to update the microcode on
769 certain Intel and AMD processors. The Intel support is for the
770 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
771 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
772 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
773 You will obviously need the actual microcode binary data itself
774 which is not shipped with the Linux kernel.
776 This option selects the general module only, you need to select
777 at least one vendor specific module as well.
779 To compile this driver as a module, choose M here: the
780 module will be called microcode.
782 config MICROCODE_INTEL
783 bool "Intel microcode patch loading support"
788 This options enables microcode patch loading support for Intel
791 For latest news and information on obtaining all the required
792 Intel ingredients for this driver, check:
793 <http://www.urbanmyth.org/microcode/>.
796 bool "AMD microcode patch loading support"
800 If you select this option, microcode patch loading support for AMD
801 processors will be enabled.
803 config MICROCODE_OLD_INTERFACE
808 tristate "/dev/cpu/*/msr - Model-specific register support"
810 This device gives privileged processes access to the x86
811 Model-Specific Registers (MSRs). It is a character device with
812 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
813 MSR accesses are directed to a specific CPU on multi-processor
817 tristate "/dev/cpu/*/cpuid - CPU information support"
819 This device gives processes access to the x86 CPUID instruction to
820 be executed on a specific processor. It is a character device
821 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
825 prompt "High Memory Support"
826 default HIGHMEM4G if !X86_NUMAQ
827 default HIGHMEM64G if X86_NUMAQ
832 depends on !X86_NUMAQ
834 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
835 However, the address space of 32-bit x86 processors is only 4
836 Gigabytes large. That means that, if you have a large amount of
837 physical memory, not all of it can be "permanently mapped" by the
838 kernel. The physical memory that's not permanently mapped is called
841 If you are compiling a kernel which will never run on a machine with
842 more than 1 Gigabyte total physical RAM, answer "off" here (default
843 choice and suitable for most users). This will result in a "3GB/1GB"
844 split: 3GB are mapped so that each process sees a 3GB virtual memory
845 space and the remaining part of the 4GB virtual memory space is used
846 by the kernel to permanently map as much physical memory as
849 If the machine has between 1 and 4 Gigabytes physical RAM, then
852 If more than 4 Gigabytes is used then answer "64GB" here. This
853 selection turns Intel PAE (Physical Address Extension) mode on.
854 PAE implements 3-level paging on IA32 processors. PAE is fully
855 supported by Linux, PAE mode is implemented on all recent Intel
856 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
857 then the kernel will not boot on CPUs that don't support PAE!
859 The actual amount of total physical memory will either be
860 auto detected or can be forced by using a kernel command line option
861 such as "mem=256M". (Try "man bootparam" or see the documentation of
862 your boot loader (lilo or loadlin) about how to pass options to the
863 kernel at boot time.)
865 If unsure, say "off".
869 depends on !X86_NUMAQ
871 Select this if you have a 32-bit processor and between 1 and 4
872 gigabytes of physical RAM.
876 depends on !M386 && !M486
879 Select this if you have a 32-bit processor and more than 4
880 gigabytes of physical RAM.
885 depends on EXPERIMENTAL
886 prompt "Memory split" if EMBEDDED
890 Select the desired split between kernel and user memory.
892 If the address range available to the kernel is less than the
893 physical memory installed, the remaining memory will be available
894 as "high memory". Accessing high memory is a little more costly
895 than low memory, as it needs to be mapped into the kernel first.
896 Note that increasing the kernel address space limits the range
897 available to user programs, making the address space there
898 tighter. Selecting anything other than the default 3G/1G split
899 will also likely make your kernel incompatible with binary-only
902 If you are not absolutely sure what you are doing, leave this
906 bool "3G/1G user/kernel split"
907 config VMSPLIT_3G_OPT
909 bool "3G/1G user/kernel split (for full 1G low memory)"
911 bool "2G/2G user/kernel split"
912 config VMSPLIT_2G_OPT
914 bool "2G/2G user/kernel split (for full 2G low memory)"
916 bool "1G/3G user/kernel split"
921 default 0xB0000000 if VMSPLIT_3G_OPT
922 default 0x80000000 if VMSPLIT_2G
923 default 0x78000000 if VMSPLIT_2G_OPT
924 default 0x40000000 if VMSPLIT_1G
930 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
933 bool "PAE (Physical Address Extension) Support"
934 depends on X86_32 && !HIGHMEM4G
936 PAE is required for NX support, and furthermore enables
937 larger swapspace support for non-overcommit purposes. It
938 has the cost of more pagetable lookup overhead, and also
939 consumes more pagetable space per process.
941 config ARCH_PHYS_ADDR_T_64BIT
942 def_bool X86_64 || X86_PAE
944 # Common NUMA Features
946 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
948 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
950 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
952 Enable NUMA (Non Uniform Memory Access) support.
953 The kernel will try to allocate memory used by a CPU on the
954 local memory controller of the CPU and add some more
955 NUMA awareness to the kernel.
957 For 32-bit this is currently highly experimental and should be only
958 used for kernel development. It might also cause boot failures.
959 For 64-bit this is recommended on all multiprocessor Opteron systems.
960 If the system is EM64T, you should say N unless your system is
963 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
964 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
968 prompt "Old style AMD Opteron NUMA detection"
969 depends on X86_64 && NUMA && PCI
971 Enable K8 NUMA node topology detection. You should say Y here if
972 you have a multi processor AMD K8 system. This uses an old
973 method to read the NUMA configuration directly from the builtin
974 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
975 instead, which also takes priority if both are compiled in.
977 config X86_64_ACPI_NUMA
979 prompt "ACPI NUMA detection"
980 depends on X86_64 && NUMA && ACPI && PCI
983 Enable ACPI SRAT based node topology detection.
985 # Some NUMA nodes have memory ranges that span
986 # other nodes. Even though a pfn is valid and
987 # between a node's start and end pfns, it may not
988 # reside on that node. See memmap_init_zone()
990 config NODES_SPAN_OTHER_NODES
992 depends on X86_64_ACPI_NUMA
995 bool "NUMA emulation"
996 depends on X86_64 && NUMA
998 Enable NUMA emulation. A flat machine will be split
999 into virtual nodes when booted with "numa=fake=N", where N is the
1000 number of nodes. This is only useful for debugging.
1003 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1005 default "9" if MAXSMP
1006 default "6" if X86_64
1007 default "4" if X86_NUMAQ
1009 depends on NEED_MULTIPLE_NODES
1011 Specify the maximum number of NUMA Nodes available on the target
1012 system. Increases memory reserved to accomodate various tables.
1014 config HAVE_ARCH_BOOTMEM_NODE
1016 depends on X86_32 && NUMA
1018 config ARCH_HAVE_MEMORY_PRESENT
1020 depends on X86_32 && DISCONTIGMEM
1022 config NEED_NODE_MEMMAP_SIZE
1024 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1026 config HAVE_ARCH_ALLOC_REMAP
1028 depends on X86_32 && NUMA
1030 config ARCH_FLATMEM_ENABLE
1032 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1034 config ARCH_DISCONTIGMEM_ENABLE
1036 depends on NUMA && X86_32
1038 config ARCH_DISCONTIGMEM_DEFAULT
1040 depends on NUMA && X86_32
1042 config ARCH_SPARSEMEM_DEFAULT
1046 config ARCH_SPARSEMEM_ENABLE
1048 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1049 select SPARSEMEM_STATIC if X86_32
1050 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1052 config ARCH_SELECT_MEMORY_MODEL
1054 depends on ARCH_SPARSEMEM_ENABLE
1056 config ARCH_MEMORY_PROBE
1058 depends on MEMORY_HOTPLUG
1063 bool "Allocate 3rd-level pagetables from highmem"
1064 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1066 The VM uses one page table entry for each page of physical memory.
1067 For systems with a lot of RAM, this can be wasteful of precious
1068 low memory. Setting this option will put user-space page table
1069 entries in high memory.
1071 config X86_CHECK_BIOS_CORRUPTION
1072 bool "Check for low memory corruption"
1074 Periodically check for memory corruption in low memory, which
1075 is suspected to be caused by BIOS. Even when enabled in the
1076 configuration, it is disabled at runtime. Enable it by
1077 setting "memory_corruption_check=1" on the kernel command
1078 line. By default it scans the low 64k of memory every 60
1079 seconds; see the memory_corruption_check_size and
1080 memory_corruption_check_period parameters in
1081 Documentation/kernel-parameters.txt to adjust this.
1083 When enabled with the default parameters, this option has
1084 almost no overhead, as it reserves a relatively small amount
1085 of memory and scans it infrequently. It both detects corruption
1086 and prevents it from affecting the running system.
1088 It is, however, intended as a diagnostic tool; if repeatable
1089 BIOS-originated corruption always affects the same memory,
1090 you can use memmap= to prevent the kernel from using that
1093 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1094 bool "Set the default setting of memory_corruption_check"
1095 depends on X86_CHECK_BIOS_CORRUPTION
1098 Set whether the default state of memory_corruption_check is
1101 config X86_RESERVE_LOW_64K
1102 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1105 Reserve the first 64K of physical RAM on BIOSes that are known
1106 to potentially corrupt that memory range. A numbers of BIOSes are
1107 known to utilize this area during suspend/resume, so it must not
1108 be used by the kernel.
1110 Set this to N if you are absolutely sure that you trust the BIOS
1111 to get all its memory reservations and usages right.
1113 If you have doubts about the BIOS (e.g. suspend/resume does not
1114 work or there's kernel crashes after certain hardware hotplug
1115 events) and it's not AMI or Phoenix, then you might want to enable
1116 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1117 corruption patterns.
1121 config MATH_EMULATION
1123 prompt "Math emulation" if X86_32
1125 Linux can emulate a math coprocessor (used for floating point
1126 operations) if you don't have one. 486DX and Pentium processors have
1127 a math coprocessor built in, 486SX and 386 do not, unless you added
1128 a 487DX or 387, respectively. (The messages during boot time can
1129 give you some hints here ["man dmesg"].) Everyone needs either a
1130 coprocessor or this emulation.
1132 If you don't have a math coprocessor, you need to say Y here; if you
1133 say Y here even though you have a coprocessor, the coprocessor will
1134 be used nevertheless. (This behavior can be changed with the kernel
1135 command line option "no387", which comes handy if your coprocessor
1136 is broken. Try "man bootparam" or see the documentation of your boot
1137 loader (lilo or loadlin) about how to pass options to the kernel at
1138 boot time.) This means that it is a good idea to say Y here if you
1139 intend to use this kernel on different machines.
1141 More information about the internals of the Linux math coprocessor
1142 emulation can be found in <file:arch/x86/math-emu/README>.
1144 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1145 kernel, it won't hurt.
1148 bool "MTRR (Memory Type Range Register) support"
1150 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1151 the Memory Type Range Registers (MTRRs) may be used to control
1152 processor access to memory ranges. This is most useful if you have
1153 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1154 allows bus write transfers to be combined into a larger transfer
1155 before bursting over the PCI/AGP bus. This can increase performance
1156 of image write operations 2.5 times or more. Saying Y here creates a
1157 /proc/mtrr file which may be used to manipulate your processor's
1158 MTRRs. Typically the X server should use this.
1160 This code has a reasonably generic interface so that similar
1161 control registers on other processors can be easily supported
1164 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1165 Registers (ARRs) which provide a similar functionality to MTRRs. For
1166 these, the ARRs are used to emulate the MTRRs.
1167 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1168 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1169 write-combining. All of these processors are supported by this code
1170 and it makes sense to say Y here if you have one of them.
1172 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1173 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1174 can lead to all sorts of problems, so it's good to say Y here.
1176 You can safely say Y even if your machine doesn't have MTRRs, you'll
1177 just add about 9 KB to your kernel.
1179 See <file:Documentation/x86/mtrr.txt> for more information.
1181 config MTRR_SANITIZER
1183 prompt "MTRR cleanup support"
1186 Convert MTRR layout from continuous to discrete, so X drivers can
1187 add writeback entries.
1189 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1190 The largest mtrr entry size for a continous block can be set with
1195 config MTRR_SANITIZER_ENABLE_DEFAULT
1196 int "MTRR cleanup enable value (0-1)"
1199 depends on MTRR_SANITIZER
1201 Enable mtrr cleanup default value
1203 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1204 int "MTRR cleanup spare reg num (0-7)"
1207 depends on MTRR_SANITIZER
1209 mtrr cleanup spare entries default, it can be changed via
1210 mtrr_spare_reg_nr=N on the kernel command line.
1214 prompt "x86 PAT support"
1217 Use PAT attributes to setup page level cache control.
1219 PATs are the modern equivalents of MTRRs and are much more
1220 flexible than MTRRs.
1222 Say N here if you see bootup problems (boot crash, boot hang,
1223 spontaneous reboots) or a non-working video driver.
1228 bool "EFI runtime service support"
1231 This enables the kernel to use EFI runtime services that are
1232 available (such as the EFI variable services).
1234 This option is only useful on systems that have EFI firmware.
1235 In addition, you should use the latest ELILO loader available
1236 at <http://elilo.sourceforge.net> in order to take advantage
1237 of EFI runtime services. However, even with this option, the
1238 resultant kernel should continue to boot on existing non-EFI
1243 prompt "Enable seccomp to safely compute untrusted bytecode"
1245 This kernel feature is useful for number crunching applications
1246 that may need to compute untrusted bytecode during their
1247 execution. By using pipes or other transports made available to
1248 the process as file descriptors supporting the read/write
1249 syscalls, it's possible to isolate those applications in
1250 their own address space using seccomp. Once seccomp is
1251 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1252 and the task is only allowed to execute a few safe syscalls
1253 defined by each seccomp mode.
1255 If unsure, say Y. Only embedded should say N here.
1257 config CC_STACKPROTECTOR
1258 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1259 depends on X86_64 && EXPERIMENTAL && BROKEN
1261 This option turns on the -fstack-protector GCC feature. This
1262 feature puts, at the beginning of critical functions, a canary
1263 value on the stack just before the return address, and validates
1264 the value just before actually returning. Stack based buffer
1265 overflows (that need to overwrite this return address) now also
1266 overwrite the canary, which gets detected and the attack is then
1267 neutralized via a kernel panic.
1269 This feature requires gcc version 4.2 or above, or a distribution
1270 gcc with the feature backported. Older versions are automatically
1271 detected and for those versions, this configuration option is ignored.
1273 config CC_STACKPROTECTOR_ALL
1274 bool "Use stack-protector for all functions"
1275 depends on CC_STACKPROTECTOR
1277 Normally, GCC only inserts the canary value protection for
1278 functions that use large-ish on-stack buffers. By enabling
1279 this option, GCC will be asked to do this for ALL functions.
1281 source kernel/Kconfig.hz
1284 bool "kexec system call"
1285 depends on X86_BIOS_REBOOT
1287 kexec is a system call that implements the ability to shutdown your
1288 current kernel, and to start another kernel. It is like a reboot
1289 but it is independent of the system firmware. And like a reboot
1290 you can start any kernel with it, not just Linux.
1292 The name comes from the similarity to the exec system call.
1294 It is an ongoing process to be certain the hardware in a machine
1295 is properly shutdown, so do not be surprised if this code does not
1296 initially work for you. It may help to enable device hotplugging
1297 support. As of this writing the exact hardware interface is
1298 strongly in flux, so no good recommendation can be made.
1301 bool "kernel crash dumps"
1302 depends on X86_64 || (X86_32 && HIGHMEM)
1304 Generate crash dump after being started by kexec.
1305 This should be normally only set in special crash dump kernels
1306 which are loaded in the main kernel with kexec-tools into
1307 a specially reserved region and then later executed after
1308 a crash by kdump/kexec. The crash dump kernel must be compiled
1309 to a memory address not used by the main kernel or BIOS using
1310 PHYSICAL_START, or it must be built as a relocatable image
1311 (CONFIG_RELOCATABLE=y).
1312 For more details see Documentation/kdump/kdump.txt
1315 bool "kexec jump (EXPERIMENTAL)"
1316 depends on EXPERIMENTAL
1317 depends on KEXEC && HIBERNATION && X86_32
1319 Jump between original kernel and kexeced kernel and invoke
1320 code in physical address mode via KEXEC
1322 config PHYSICAL_START
1323 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1324 default "0x1000000" if X86_NUMAQ
1325 default "0x200000" if X86_64
1328 This gives the physical address where the kernel is loaded.
1330 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1331 bzImage will decompress itself to above physical address and
1332 run from there. Otherwise, bzImage will run from the address where
1333 it has been loaded by the boot loader and will ignore above physical
1336 In normal kdump cases one does not have to set/change this option
1337 as now bzImage can be compiled as a completely relocatable image
1338 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1339 address. This option is mainly useful for the folks who don't want
1340 to use a bzImage for capturing the crash dump and want to use a
1341 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1342 to be specifically compiled to run from a specific memory area
1343 (normally a reserved region) and this option comes handy.
1345 So if you are using bzImage for capturing the crash dump, leave
1346 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1347 Otherwise if you plan to use vmlinux for capturing the crash dump
1348 change this value to start of the reserved region (Typically 16MB
1349 0x1000000). In other words, it can be set based on the "X" value as
1350 specified in the "crashkernel=YM@XM" command line boot parameter
1351 passed to the panic-ed kernel. Typically this parameter is set as
1352 crashkernel=64M@16M. Please take a look at
1353 Documentation/kdump/kdump.txt for more details about crash dumps.
1355 Usage of bzImage for capturing the crash dump is recommended as
1356 one does not have to build two kernels. Same kernel can be used
1357 as production kernel and capture kernel. Above option should have
1358 gone away after relocatable bzImage support is introduced. But it
1359 is present because there are users out there who continue to use
1360 vmlinux for dump capture. This option should go away down the
1363 Don't change this unless you know what you are doing.
1366 bool "Build a relocatable kernel (EXPERIMENTAL)"
1367 depends on EXPERIMENTAL
1369 This builds a kernel image that retains relocation information
1370 so it can be loaded someplace besides the default 1MB.
1371 The relocations tend to make the kernel binary about 10% larger,
1372 but are discarded at runtime.
1374 One use is for the kexec on panic case where the recovery kernel
1375 must live at a different physical address than the primary
1378 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1379 it has been loaded at and the compile time physical address
1380 (CONFIG_PHYSICAL_START) is ignored.
1382 config PHYSICAL_ALIGN
1384 prompt "Alignment value to which kernel should be aligned" if X86_32
1385 default "0x100000" if X86_32
1386 default "0x200000" if X86_64
1387 range 0x2000 0x400000
1389 This value puts the alignment restrictions on physical address
1390 where kernel is loaded and run from. Kernel is compiled for an
1391 address which meets above alignment restriction.
1393 If bootloader loads the kernel at a non-aligned address and
1394 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1395 address aligned to above value and run from there.
1397 If bootloader loads the kernel at a non-aligned address and
1398 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1399 load address and decompress itself to the address it has been
1400 compiled for and run from there. The address for which kernel is
1401 compiled already meets above alignment restrictions. Hence the
1402 end result is that kernel runs from a physical address meeting
1403 above alignment restrictions.
1405 Don't change this unless you know what you are doing.
1408 bool "Support for hot-pluggable CPUs"
1409 depends on SMP && HOTPLUG && !X86_VOYAGER
1411 Say Y here to allow turning CPUs off and on. CPUs can be
1412 controlled through /sys/devices/system/cpu.
1413 ( Note: power management support will enable this option
1414 automatically on SMP systems. )
1415 Say N if you want to disable CPU hotplug.
1419 prompt "Compat VDSO support"
1420 depends on X86_32 || IA32_EMULATION
1422 Map the 32-bit VDSO to the predictable old-style address too.
1424 Say N here if you are running a sufficiently recent glibc
1425 version (2.3.3 or later), to remove the high-mapped
1426 VDSO mapping and to exclusively use the randomized VDSO.
1431 bool "Built-in kernel command line"
1434 Allow for specifying boot arguments to the kernel at
1435 build time. On some systems (e.g. embedded ones), it is
1436 necessary or convenient to provide some or all of the
1437 kernel boot arguments with the kernel itself (that is,
1438 to not rely on the boot loader to provide them.)
1440 To compile command line arguments into the kernel,
1441 set this option to 'Y', then fill in the
1442 the boot arguments in CONFIG_CMDLINE.
1444 Systems with fully functional boot loaders (i.e. non-embedded)
1445 should leave this option set to 'N'.
1448 string "Built-in kernel command string"
1449 depends on CMDLINE_BOOL
1452 Enter arguments here that should be compiled into the kernel
1453 image and used at boot time. If the boot loader provides a
1454 command line at boot time, it is appended to this string to
1455 form the full kernel command line, when the system boots.
1457 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1458 change this behavior.
1460 In most cases, the command line (whether built-in or provided
1461 by the boot loader) should specify the device for the root
1464 config CMDLINE_OVERRIDE
1465 bool "Built-in command line overrides boot loader arguments"
1467 depends on CMDLINE_BOOL
1469 Set this option to 'Y' to have the kernel ignore the boot loader
1470 command line, and use ONLY the built-in command line.
1472 This is used to work around broken boot loaders. This should
1473 be set to 'N' under normal conditions.
1477 config ARCH_ENABLE_MEMORY_HOTPLUG
1479 depends on X86_64 || (X86_32 && HIGHMEM)
1481 config HAVE_ARCH_EARLY_PFN_TO_NID
1485 menu "Power management options"
1486 depends on !X86_VOYAGER
1488 config ARCH_HIBERNATION_HEADER
1490 depends on X86_64 && HIBERNATION
1492 source "kernel/power/Kconfig"
1494 source "drivers/acpi/Kconfig"
1499 depends on APM || APM_MODULE
1502 tristate "APM (Advanced Power Management) BIOS support"
1503 depends on X86_32 && PM_SLEEP
1505 APM is a BIOS specification for saving power using several different
1506 techniques. This is mostly useful for battery powered laptops with
1507 APM compliant BIOSes. If you say Y here, the system time will be
1508 reset after a RESUME operation, the /proc/apm device will provide
1509 battery status information, and user-space programs will receive
1510 notification of APM "events" (e.g. battery status change).
1512 If you select "Y" here, you can disable actual use of the APM
1513 BIOS by passing the "apm=off" option to the kernel at boot time.
1515 Note that the APM support is almost completely disabled for
1516 machines with more than one CPU.
1518 In order to use APM, you will need supporting software. For location
1519 and more information, read <file:Documentation/power/pm.txt> and the
1520 Battery Powered Linux mini-HOWTO, available from
1521 <http://www.tldp.org/docs.html#howto>.
1523 This driver does not spin down disk drives (see the hdparm(8)
1524 manpage ("man 8 hdparm") for that), and it doesn't turn off
1525 VESA-compliant "green" monitors.
1527 This driver does not support the TI 4000M TravelMate and the ACER
1528 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1529 desktop machines also don't have compliant BIOSes, and this driver
1530 may cause those machines to panic during the boot phase.
1532 Generally, if you don't have a battery in your machine, there isn't
1533 much point in using this driver and you should say N. If you get
1534 random kernel OOPSes or reboots that don't seem to be related to
1535 anything, try disabling/enabling this option (or disabling/enabling
1538 Some other things you should try when experiencing seemingly random,
1541 1) make sure that you have enough swap space and that it is
1543 2) pass the "no-hlt" option to the kernel
1544 3) switch on floating point emulation in the kernel and pass
1545 the "no387" option to the kernel
1546 4) pass the "floppy=nodma" option to the kernel
1547 5) pass the "mem=4M" option to the kernel (thereby disabling
1548 all but the first 4 MB of RAM)
1549 6) make sure that the CPU is not over clocked.
1550 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1551 8) disable the cache from your BIOS settings
1552 9) install a fan for the video card or exchange video RAM
1553 10) install a better fan for the CPU
1554 11) exchange RAM chips
1555 12) exchange the motherboard.
1557 To compile this driver as a module, choose M here: the
1558 module will be called apm.
1562 config APM_IGNORE_USER_SUSPEND
1563 bool "Ignore USER SUSPEND"
1565 This option will ignore USER SUSPEND requests. On machines with a
1566 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1567 series notebooks, it is necessary to say Y because of a BIOS bug.
1569 config APM_DO_ENABLE
1570 bool "Enable PM at boot time"
1572 Enable APM features at boot time. From page 36 of the APM BIOS
1573 specification: "When disabled, the APM BIOS does not automatically
1574 power manage devices, enter the Standby State, enter the Suspend
1575 State, or take power saving steps in response to CPU Idle calls."
1576 This driver will make CPU Idle calls when Linux is idle (unless this
1577 feature is turned off -- see "Do CPU IDLE calls", below). This
1578 should always save battery power, but more complicated APM features
1579 will be dependent on your BIOS implementation. You may need to turn
1580 this option off if your computer hangs at boot time when using APM
1581 support, or if it beeps continuously instead of suspending. Turn
1582 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1583 T400CDT. This is off by default since most machines do fine without
1587 bool "Make CPU Idle calls when idle"
1589 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1590 On some machines, this can activate improved power savings, such as
1591 a slowed CPU clock rate, when the machine is idle. These idle calls
1592 are made after the idle loop has run for some length of time (e.g.,
1593 333 mS). On some machines, this will cause a hang at boot time or
1594 whenever the CPU becomes idle. (On machines with more than one CPU,
1595 this option does nothing.)
1597 config APM_DISPLAY_BLANK
1598 bool "Enable console blanking using APM"
1600 Enable console blanking using the APM. Some laptops can use this to
1601 turn off the LCD backlight when the screen blanker of the Linux
1602 virtual console blanks the screen. Note that this is only used by
1603 the virtual console screen blanker, and won't turn off the backlight
1604 when using the X Window system. This also doesn't have anything to
1605 do with your VESA-compliant power-saving monitor. Further, this
1606 option doesn't work for all laptops -- it might not turn off your
1607 backlight at all, or it might print a lot of errors to the console,
1608 especially if you are using gpm.
1610 config APM_ALLOW_INTS
1611 bool "Allow interrupts during APM BIOS calls"
1613 Normally we disable external interrupts while we are making calls to
1614 the APM BIOS as a measure to lessen the effects of a badly behaving
1615 BIOS implementation. The BIOS should reenable interrupts if it
1616 needs to. Unfortunately, some BIOSes do not -- especially those in
1617 many of the newer IBM Thinkpads. If you experience hangs when you
1618 suspend, try setting this to Y. Otherwise, say N.
1620 config APM_REAL_MODE_POWER_OFF
1621 bool "Use real mode APM BIOS call to power off"
1623 Use real mode APM BIOS calls to switch off the computer. This is
1624 a work-around for a number of buggy BIOSes. Switch this option on if
1625 your computer crashes instead of powering off properly.
1629 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1631 source "drivers/cpuidle/Kconfig"
1633 source "drivers/idle/Kconfig"
1638 menu "Bus options (PCI etc.)"
1643 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1645 Find out whether you have a PCI motherboard. PCI is the name of a
1646 bus system, i.e. the way the CPU talks to the other stuff inside
1647 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1648 VESA. If you have PCI, say Y, otherwise N.
1651 prompt "PCI access mode"
1652 depends on X86_32 && PCI
1655 On PCI systems, the BIOS can be used to detect the PCI devices and
1656 determine their configuration. However, some old PCI motherboards
1657 have BIOS bugs and may crash if this is done. Also, some embedded
1658 PCI-based systems don't have any BIOS at all. Linux can also try to
1659 detect the PCI hardware directly without using the BIOS.
1661 With this option, you can specify how Linux should detect the
1662 PCI devices. If you choose "BIOS", the BIOS will be used,
1663 if you choose "Direct", the BIOS won't be used, and if you
1664 choose "MMConfig", then PCI Express MMCONFIG will be used.
1665 If you choose "Any", the kernel will try MMCONFIG, then the
1666 direct access method and falls back to the BIOS if that doesn't
1667 work. If unsure, go with the default, which is "Any".
1672 config PCI_GOMMCONFIG
1689 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1691 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1694 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1698 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1702 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1709 bool "Support mmconfig PCI config space access"
1710 depends on X86_64 && PCI && ACPI
1713 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1714 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1716 DMA remapping (DMAR) devices support enables independent address
1717 translations for Direct Memory Access (DMA) from devices.
1718 These DMA remapping devices are reported via ACPI tables
1719 and include PCI device scope covered by these DMA
1724 prompt "Support for Graphics workaround"
1727 Current Graphics drivers tend to use physical address
1728 for DMA and avoid using DMA APIs. Setting this config
1729 option permits the IOMMU driver to set a unity map for
1730 all the OS-visible memory. Hence the driver can continue
1731 to use physical addresses for DMA.
1733 config DMAR_FLOPPY_WA
1737 Floppy disk drivers are know to bypass DMA API calls
1738 thereby failing to work when IOMMU is enabled. This
1739 workaround will setup a 1:1 mapping for the first
1740 16M to make floppy (an ISA device) work.
1743 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1744 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1746 Supports Interrupt remapping for IO-APIC and MSI devices.
1747 To use x2apic mode in the CPU's which support x2APIC enhancements or
1748 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1750 source "drivers/pci/pcie/Kconfig"
1752 source "drivers/pci/Kconfig"
1754 # x86_64 have no ISA slots, but do have ISA-style DMA.
1762 depends on !X86_VOYAGER
1764 Find out whether you have ISA slots on your motherboard. ISA is the
1765 name of a bus system, i.e. the way the CPU talks to the other stuff
1766 inside your box. Other bus systems are PCI, EISA, MicroChannel
1767 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1768 newer boards don't support it. If you have ISA, say Y, otherwise N.
1774 The Extended Industry Standard Architecture (EISA) bus was
1775 developed as an open alternative to the IBM MicroChannel bus.
1777 The EISA bus provided some of the features of the IBM MicroChannel
1778 bus while maintaining backward compatibility with cards made for
1779 the older ISA bus. The EISA bus saw limited use between 1988 and
1780 1995 when it was made obsolete by the PCI bus.
1782 Say Y here if you are building a kernel for an EISA-based machine.
1786 source "drivers/eisa/Kconfig"
1789 bool "MCA support" if !X86_VOYAGER
1790 default y if X86_VOYAGER
1792 MicroChannel Architecture is found in some IBM PS/2 machines and
1793 laptops. It is a bus system similar to PCI or ISA. See
1794 <file:Documentation/mca.txt> (and especially the web page given
1795 there) before attempting to build an MCA bus kernel.
1797 source "drivers/mca/Kconfig"
1800 tristate "NatSemi SCx200 support"
1801 depends on !X86_VOYAGER
1803 This provides basic support for National Semiconductor's
1804 (now AMD's) Geode processors. The driver probes for the
1805 PCI-IDs of several on-chip devices, so its a good dependency
1806 for other scx200_* drivers.
1808 If compiled as a module, the driver is named scx200.
1810 config SCx200HR_TIMER
1811 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1812 depends on SCx200 && GENERIC_TIME
1815 This driver provides a clocksource built upon the on-chip
1816 27MHz high-resolution timer. Its also a workaround for
1817 NSC Geode SC-1100's buggy TSC, which loses time when the
1818 processor goes idle (as is done by the scheduler). The
1819 other workaround is idle=poll boot option.
1821 config GEODE_MFGPT_TIMER
1823 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1824 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1826 This driver provides a clock event source based on the MFGPT
1827 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1828 MFGPTs have a better resolution and max interval than the
1829 generic PIT, and are suitable for use as high-res timers.
1832 bool "One Laptop Per Child support"
1835 Add support for detecting the unique features of the OLPC
1842 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1844 source "drivers/pcmcia/Kconfig"
1846 source "drivers/pci/hotplug/Kconfig"
1851 menu "Executable file formats / Emulations"
1853 source "fs/Kconfig.binfmt"
1855 config IA32_EMULATION
1856 bool "IA32 Emulation"
1858 select COMPAT_BINFMT_ELF
1860 Include code to run 32-bit programs under a 64-bit kernel. You should
1861 likely turn this on, unless you're 100% sure that you don't have any
1862 32-bit programs left.
1865 tristate "IA32 a.out support"
1866 depends on IA32_EMULATION
1868 Support old a.out binaries in the 32bit emulation.
1872 depends on IA32_EMULATION
1874 config COMPAT_FOR_U64_ALIGNMENT
1878 config SYSVIPC_COMPAT
1880 depends on COMPAT && SYSVIPC
1885 source "net/Kconfig"
1887 source "drivers/Kconfig"
1889 source "drivers/firmware/Kconfig"
1893 source "arch/x86/Kconfig.debug"
1895 source "security/Kconfig"
1897 source "crypto/Kconfig"
1899 source "arch/x86/kvm/Kconfig"
1901 source "lib/Kconfig"
projects / linux-2.6 / blob