2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
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_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
145 config ARCH_SUSPEND_POSSIBLE
152 config ARCH_POPULATES_NODE_MAP
159 config ARCH_SUPPORTS_OPTIMIZED_INLINING
162 # Use the generic interrupt handling code in kernel/irq/:
163 config GENERIC_HARDIRQS
167 config GENERIC_IRQ_PROBE
171 config GENERIC_PENDING_IRQ
173 depends on GENERIC_HARDIRQS && SMP
176 config USE_GENERIC_SMP_HELPERS
182 depends on X86_32 && SMP
186 depends on X86_64 && SMP
193 config X86_TRAMPOLINE
195 depends on SMP || (64BIT && ACPI_SLEEP)
200 source "init/Kconfig"
201 source "kernel/Kconfig.freezer"
203 menu "Processor type and features"
205 source "kernel/time/Kconfig"
208 bool "Symmetric multi-processing support"
210 This enables support for systems with more than one CPU. If you have
211 a system with only one CPU, like most personal computers, say N. If
212 you have a system with more than one CPU, say Y.
214 If you say N here, the kernel will run on single and multiprocessor
215 machines, but will use only one CPU of a multiprocessor machine. If
216 you say Y here, the kernel will run on many, but not all,
217 singleprocessor machines. On a singleprocessor machine, the kernel
218 will run faster if you say N here.
220 Note that if you say Y here and choose architecture "586" or
221 "Pentium" under "Processor family", the kernel will not work on 486
222 architectures. Similarly, multiprocessor kernels for the "PPro"
223 architecture may not work on all Pentium based boards.
225 People using multiprocessor machines who say Y here should also say
226 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
227 Management" code will be disabled if you say Y here.
229 See also <file:Documentation/i386/IO-APIC.txt>,
230 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
231 <http://www.tldp.org/docs.html#howto>.
233 If you don't know what to do here, say N.
236 bool "Support sparse irq numbering"
237 depends on PCI_MSI || HT_IRQ
239 This enables support for sparse irqs. This is useful for distro
240 kernels that want to define a high CONFIG_NR_CPUS value but still
241 want to have low kernel memory footprint on smaller machines.
243 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
244 out the irq_desc[] array in a more NUMA-friendly way. )
246 If you don't know what to do here, say N.
248 config NUMA_MIGRATE_IRQ_DESC
249 bool "Move irq desc when changing irq smp_affinity"
250 depends on SPARSE_IRQ && NUMA
253 This enables moving irq_desc to cpu/node that irq will use handled.
255 If you don't know what to do here, say N.
258 bool "Enable MPS table" if ACPI
260 depends on X86_LOCAL_APIC
262 For old smp systems that do not have proper acpi support. Newer systems
263 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
266 prompt "Subarchitecture Type"
272 Choose this option if your computer is a standard PC or compatible.
278 Select this for an AMD Elan processor.
280 Do not use this option for K6/Athlon/Opteron processors!
282 If unsure, choose "PC-compatible" instead.
286 depends on X86_32 && SMP && !PCI && BROKEN
288 Voyager is an MCA-based 32-way capable SMP architecture proprietary
289 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
293 If you do not specifically know you have a Voyager based machine,
294 say N here, otherwise the kernel you build will not be bootable.
296 config X86_GENERICARCH
297 bool "Generic architecture"
300 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
301 subarchitectures. It is intended for a generic binary kernel.
302 if you select them all, kernel will probe it one by one. and will
308 bool "NUMAQ (IBM/Sequent)"
309 depends on SMP && X86_32 && PCI && X86_MPPARSE
312 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
313 NUMA multiquad box. This changes the way that processors are
314 bootstrapped, and uses Clustered Logical APIC addressing mode instead
315 of Flat Logical. You will need a new lynxer.elf file to flash your
316 firmware with - send email to <Martin.Bligh@us.ibm.com>.
319 bool "Summit/EXA (IBM x440)"
320 depends on X86_32 && SMP
322 This option is needed for IBM systems that use the Summit/EXA chipset.
323 In particular, it is needed for the x440.
326 bool "Support for Unisys ES7000 IA32 series"
327 depends on X86_32 && SMP
329 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
330 supposed to run on an IA32-based Unisys ES7000 system.
333 bool "Support for big SMP systems with more than 8 CPUs"
334 depends on X86_32 && SMP
336 This option is needed for the systems that have more than 8 CPUs
337 and if the system is not of any sub-arch type above.
342 bool "Support for ScaleMP vSMP"
344 depends on X86_64 && PCI
346 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
347 supposed to run on these EM64T-based machines. Only choose this option
348 if you have one of these machines.
353 bool "SGI 320/540 (Visual Workstation)"
354 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
356 The SGI Visual Workstation series is an IA32-based workstation
357 based on SGI systems chips with some legacy PC hardware attached.
359 Say Y here to create a kernel to run on the SGI 320 or 540.
361 A kernel compiled for the Visual Workstation will run on general
362 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
365 bool "RDC R-321x SoC"
368 select X86_REBOOTFIXUPS
370 This option is needed for RDC R-321x system-on-chip, also known
372 If you don't have one of these chips, you should say N here.
375 bool "SGI Ultraviolet"
378 This option is needed in order to support SGI Ultraviolet systems.
379 If you don't have one of these, you should say N here.
381 config SCHED_OMIT_FRAME_POINTER
383 prompt "Single-depth WCHAN output"
386 Calculate simpler /proc/<PID>/wchan values. If this option
387 is disabled then wchan values will recurse back to the
388 caller function. This provides more accurate wchan values,
389 at the expense of slightly more scheduling overhead.
391 If in doubt, say "Y".
393 menuconfig PARAVIRT_GUEST
394 bool "Paravirtualized guest support"
396 Say Y here to get to see options related to running Linux under
397 various hypervisors. This option alone does not add any kernel code.
399 If you say N, all options in this submenu will be skipped and disabled.
403 source "arch/x86/xen/Kconfig"
406 bool "VMI Guest support"
410 VMI provides a paravirtualized interface to the VMware ESX server
411 (it could be used by other hypervisors in theory too, but is not
412 at the moment), by linking the kernel to a GPL-ed ROM module
413 provided by the hypervisor.
416 bool "KVM paravirtualized clock"
418 select PARAVIRT_CLOCK
420 Turning on this option will allow you to run a paravirtualized clock
421 when running over the KVM hypervisor. Instead of relying on a PIT
422 (or probably other) emulation by the underlying device model, the host
423 provides the guest with timing infrastructure such as time of day, and
427 bool "KVM Guest support"
430 This option enables various optimizations for running under the KVM
433 source "arch/x86/lguest/Kconfig"
436 bool "Enable paravirtualization code"
438 This changes the kernel so it can modify itself when it is run
439 under a hypervisor, potentially improving performance significantly
440 over full virtualization. However, when run without a hypervisor
441 the kernel is theoretically slower and slightly larger.
443 config PARAVIRT_CLOCK
449 config PARAVIRT_DEBUG
450 bool "paravirt-ops debugging"
451 depends on PARAVIRT && DEBUG_KERNEL
453 Enable to debug paravirt_ops internals. Specifically, BUG if
454 a paravirt_op is missing when it is called.
459 This option adds a kernel parameter 'memtest', which allows memtest
461 memtest=0, mean disabled; -- default
462 memtest=1, mean do 1 test pattern;
464 memtest=4, mean do 4 test patterns.
465 If you are unsure how to answer this question, answer N.
467 config X86_SUMMIT_NUMA
469 depends on X86_32 && NUMA && X86_GENERICARCH
471 config X86_CYCLONE_TIMER
473 depends on X86_GENERICARCH
475 source "arch/x86/Kconfig.cpu"
479 prompt "HPET Timer Support" if X86_32
481 Use the IA-PC HPET (High Precision Event Timer) to manage
482 time in preference to the PIT and RTC, if a HPET is
484 HPET is the next generation timer replacing legacy 8254s.
485 The HPET provides a stable time base on SMP
486 systems, unlike the TSC, but it is more expensive to access,
487 as it is off-chip. You can find the HPET spec at
488 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
490 You can safely choose Y here. However, HPET will only be
491 activated if the platform and the BIOS support this feature.
492 Otherwise the 8254 will be used for timing services.
494 Choose N to continue using the legacy 8254 timer.
496 config HPET_EMULATE_RTC
498 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
500 # Mark as embedded because too many people got it wrong.
501 # The code disables itself when not needed.
504 bool "Enable DMI scanning" if EMBEDDED
506 Enabled scanning of DMI to identify machine quirks. Say Y
507 here unless you have verified that your setup is not
508 affected by entries in the DMI blacklist. Required by PNP
512 bool "GART IOMMU support" if EMBEDDED
516 depends on X86_64 && PCI
518 Support for full DMA access of devices with 32bit memory access only
519 on systems with more than 3GB. This is usually needed for USB,
520 sound, many IDE/SATA chipsets and some other devices.
521 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
522 based hardware IOMMU and a software bounce buffer based IOMMU used
523 on Intel systems and as fallback.
524 The code is only active when needed (enough memory and limited
525 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
529 bool "IBM Calgary IOMMU support"
531 depends on X86_64 && PCI && EXPERIMENTAL
533 Support for hardware IOMMUs in IBM's xSeries x366 and x460
534 systems. Needed to run systems with more than 3GB of memory
535 properly with 32-bit PCI devices that do not support DAC
536 (Double Address Cycle). Calgary also supports bus level
537 isolation, where all DMAs pass through the IOMMU. This
538 prevents them from going anywhere except their intended
539 destination. This catches hard-to-find kernel bugs and
540 mis-behaving drivers and devices that do not use the DMA-API
541 properly to set up their DMA buffers. The IOMMU can be
542 turned off at boot time with the iommu=off parameter.
543 Normally the kernel will make the right choice by itself.
546 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
548 prompt "Should Calgary be enabled by default?"
549 depends on CALGARY_IOMMU
551 Should Calgary be enabled by default? if you choose 'y', Calgary
552 will be used (if it exists). If you choose 'n', Calgary will not be
553 used even if it exists. If you choose 'n' and would like to use
554 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
558 bool "AMD IOMMU support"
561 depends on X86_64 && PCI && ACPI
563 With this option you can enable support for AMD IOMMU hardware in
564 your system. An IOMMU is a hardware component which provides
565 remapping of DMA memory accesses from devices. With an AMD IOMMU you
566 can isolate the the DMA memory of different devices and protect the
567 system from misbehaving device drivers or hardware.
569 You can find out if your system has an AMD IOMMU if you look into
570 your BIOS for an option to enable it or if you have an IVRS ACPI
573 config AMD_IOMMU_STATS
574 bool "Export AMD IOMMU statistics to debugfs"
578 This option enables code in the AMD IOMMU driver to collect various
579 statistics about whats happening in the driver and exports that
580 information to userspace via debugfs.
583 # need this always selected by IOMMU for the VIA workaround
587 Support for software bounce buffers used on x86-64 systems
588 which don't have a hardware IOMMU (e.g. the current generation
589 of Intel's x86-64 CPUs). Using this PCI devices which can only
590 access 32-bits of memory can be used on systems with more than
591 3 GB of memory. If unsure, say Y.
594 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
597 def_bool (AMD_IOMMU || DMAR)
600 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
601 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
602 select CPUMASK_OFFSTACK
605 Configure maximum number of CPUS and NUMA Nodes for this architecture.
609 int "Maximum number of CPUs" if SMP && !MAXSMP
610 range 2 512 if SMP && !MAXSMP
612 default "4096" if MAXSMP
613 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
616 This allows you to specify the maximum number of CPUs which this
617 kernel will support. The maximum supported value is 512 and the
618 minimum value which makes sense is 2.
620 This is purely to save memory - each supported CPU adds
621 approximately eight kilobytes to the kernel image.
624 bool "SMT (Hyperthreading) scheduler support"
627 SMT scheduler support improves the CPU scheduler's decision making
628 when dealing with Intel Pentium 4 chips with HyperThreading at a
629 cost of slightly increased overhead in some places. If unsure say
634 prompt "Multi-core scheduler support"
637 Multi-core scheduler support improves the CPU scheduler's decision
638 making when dealing with multi-core CPU chips at a cost of slightly
639 increased overhead in some places. If unsure say N here.
641 source "kernel/Kconfig.preempt"
644 bool "Local APIC support on uniprocessors"
645 depends on X86_32 && !SMP && !X86_GENERICARCH
647 A local APIC (Advanced Programmable Interrupt Controller) is an
648 integrated interrupt controller in the CPU. If you have a single-CPU
649 system which has a processor with a local APIC, you can say Y here to
650 enable and use it. If you say Y here even though your machine doesn't
651 have a local APIC, then the kernel will still run with no slowdown at
652 all. The local APIC supports CPU-generated self-interrupts (timer,
653 performance counters), and the NMI watchdog which detects hard
657 bool "IO-APIC support on uniprocessors"
658 depends on X86_UP_APIC
660 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
661 SMP-capable replacement for PC-style interrupt controllers. Most
662 SMP systems and many recent uniprocessor systems have one.
664 If you have a single-CPU system with an IO-APIC, you can say Y here
665 to use it. If you say Y here even though your machine doesn't have
666 an IO-APIC, then the kernel will still run with no slowdown at all.
668 config X86_LOCAL_APIC
670 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
674 depends on X86_64 || SMP || X86_GENERICARCH || X86_UP_APIC
676 config X86_VISWS_APIC
678 depends on X86_32 && X86_VISWS
680 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
681 bool "Reroute for broken boot IRQs"
683 depends on X86_IO_APIC
685 This option enables a workaround that fixes a source of
686 spurious interrupts. This is recommended when threaded
687 interrupt handling is used on systems where the generation of
688 superfluous "boot interrupts" cannot be disabled.
690 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
691 entry in the chipset's IO-APIC is masked (as, e.g. the RT
692 kernel does during interrupt handling). On chipsets where this
693 boot IRQ generation cannot be disabled, this workaround keeps
694 the original IRQ line masked so that only the equivalent "boot
695 IRQ" is delivered to the CPUs. The workaround also tells the
696 kernel to set up the IRQ handler on the boot IRQ line. In this
697 way only one interrupt is delivered to the kernel. Otherwise
698 the spurious second interrupt may cause the kernel to bring
699 down (vital) interrupt lines.
701 Only affects "broken" chipsets. Interrupt sharing may be
702 increased on these systems.
705 bool "Machine Check Exception"
707 Machine Check Exception support allows the processor to notify the
708 kernel if it detects a problem (e.g. overheating, component failure).
709 The action the kernel takes depends on the severity of the problem,
710 ranging from a warning message on the console, to halting the machine.
711 Your processor must be a Pentium or newer to support this - check the
712 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
713 have a design flaw which leads to false MCE events - hence MCE is
714 disabled on all P5 processors, unless explicitly enabled with "mce"
715 as a boot argument. Similarly, if MCE is built in and creates a
716 problem on some new non-standard machine, you can boot with "nomce"
717 to disable it. MCE support simply ignores non-MCE processors like
718 the 386 and 486, so nearly everyone can say Y here.
722 prompt "Intel MCE features"
723 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
725 Additional support for intel specific MCE features such as
730 prompt "AMD MCE features"
731 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
733 Additional support for AMD specific MCE features such as
734 the DRAM Error Threshold.
736 config X86_MCE_NONFATAL
737 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
738 depends on X86_32 && X86_MCE
740 Enabling this feature starts a timer that triggers every 5 seconds which
741 will look at the machine check registers to see if anything happened.
742 Non-fatal problems automatically get corrected (but still logged).
743 Disable this if you don't want to see these messages.
744 Seeing the messages this option prints out may be indicative of dying
745 or out-of-spec (ie, overclocked) hardware.
746 This option only does something on certain CPUs.
747 (AMD Athlon/Duron and Intel Pentium 4)
749 config X86_MCE_P4THERMAL
750 bool "check for P4 thermal throttling interrupt."
751 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
753 Enabling this feature will cause a message to be printed when the P4
754 enters thermal throttling.
757 bool "Enable VM86 support" if EMBEDDED
761 This option is required by programs like DOSEMU to run 16-bit legacy
762 code on X86 processors. It also may be needed by software like
763 XFree86 to initialize some video cards via BIOS. Disabling this
764 option saves about 6k.
767 tristate "Toshiba Laptop support"
770 This adds a driver to safely access the System Management Mode of
771 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
772 not work on models with a Phoenix BIOS. The System Management Mode
773 is used to set the BIOS and power saving options on Toshiba portables.
775 For information on utilities to make use of this driver see the
776 Toshiba Linux utilities web site at:
777 <http://www.buzzard.org.uk/toshiba/>.
779 Say Y if you intend to run this kernel on a Toshiba portable.
783 tristate "Dell laptop support"
785 This adds a driver to safely access the System Management Mode
786 of the CPU on the Dell Inspiron 8000. The System Management Mode
787 is used to read cpu temperature and cooling fan status and to
788 control the fans on the I8K portables.
790 This driver has been tested only on the Inspiron 8000 but it may
791 also work with other Dell laptops. You can force loading on other
792 models by passing the parameter `force=1' to the module. Use at
795 For information on utilities to make use of this driver see the
796 I8K Linux utilities web site at:
797 <http://people.debian.org/~dz/i8k/>
799 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
802 config X86_REBOOTFIXUPS
803 bool "Enable X86 board specific fixups for reboot"
806 This enables chipset and/or board specific fixups to be done
807 in order to get reboot to work correctly. This is only needed on
808 some combinations of hardware and BIOS. The symptom, for which
809 this config is intended, is when reboot ends with a stalled/hung
812 Currently, the only fixup is for the Geode machines using
813 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
815 Say Y if you want to enable the fixup. Currently, it's safe to
816 enable this option even if you don't need it.
820 tristate "/dev/cpu/microcode - microcode support"
823 If you say Y here, you will be able to update the microcode on
824 certain Intel and AMD processors. The Intel support is for the
825 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
826 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
827 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
828 You will obviously need the actual microcode binary data itself
829 which is not shipped with the Linux kernel.
831 This option selects the general module only, you need to select
832 at least one vendor specific module as well.
834 To compile this driver as a module, choose M here: the
835 module will be called microcode.
837 config MICROCODE_INTEL
838 bool "Intel microcode patch loading support"
843 This options enables microcode patch loading support for Intel
846 For latest news and information on obtaining all the required
847 Intel ingredients for this driver, check:
848 <http://www.urbanmyth.org/microcode/>.
851 bool "AMD microcode patch loading support"
855 If you select this option, microcode patch loading support for AMD
856 processors will be enabled.
858 config MICROCODE_OLD_INTERFACE
863 tristate "/dev/cpu/*/msr - Model-specific register support"
865 This device gives privileged processes access to the x86
866 Model-Specific Registers (MSRs). It is a character device with
867 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
868 MSR accesses are directed to a specific CPU on multi-processor
872 tristate "/dev/cpu/*/cpuid - CPU information support"
874 This device gives processes access to the x86 CPUID instruction to
875 be executed on a specific processor. It is a character device
876 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
880 prompt "High Memory Support"
881 default HIGHMEM4G if !X86_NUMAQ
882 default HIGHMEM64G if X86_NUMAQ
887 depends on !X86_NUMAQ
889 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
890 However, the address space of 32-bit x86 processors is only 4
891 Gigabytes large. That means that, if you have a large amount of
892 physical memory, not all of it can be "permanently mapped" by the
893 kernel. The physical memory that's not permanently mapped is called
896 If you are compiling a kernel which will never run on a machine with
897 more than 1 Gigabyte total physical RAM, answer "off" here (default
898 choice and suitable for most users). This will result in a "3GB/1GB"
899 split: 3GB are mapped so that each process sees a 3GB virtual memory
900 space and the remaining part of the 4GB virtual memory space is used
901 by the kernel to permanently map as much physical memory as
904 If the machine has between 1 and 4 Gigabytes physical RAM, then
907 If more than 4 Gigabytes is used then answer "64GB" here. This
908 selection turns Intel PAE (Physical Address Extension) mode on.
909 PAE implements 3-level paging on IA32 processors. PAE is fully
910 supported by Linux, PAE mode is implemented on all recent Intel
911 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
912 then the kernel will not boot on CPUs that don't support PAE!
914 The actual amount of total physical memory will either be
915 auto detected or can be forced by using a kernel command line option
916 such as "mem=256M". (Try "man bootparam" or see the documentation of
917 your boot loader (lilo or loadlin) about how to pass options to the
918 kernel at boot time.)
920 If unsure, say "off".
924 depends on !X86_NUMAQ
926 Select this if you have a 32-bit processor and between 1 and 4
927 gigabytes of physical RAM.
931 depends on !M386 && !M486
934 Select this if you have a 32-bit processor and more than 4
935 gigabytes of physical RAM.
940 depends on EXPERIMENTAL
941 prompt "Memory split" if EMBEDDED
945 Select the desired split between kernel and user memory.
947 If the address range available to the kernel is less than the
948 physical memory installed, the remaining memory will be available
949 as "high memory". Accessing high memory is a little more costly
950 than low memory, as it needs to be mapped into the kernel first.
951 Note that increasing the kernel address space limits the range
952 available to user programs, making the address space there
953 tighter. Selecting anything other than the default 3G/1G split
954 will also likely make your kernel incompatible with binary-only
957 If you are not absolutely sure what you are doing, leave this
961 bool "3G/1G user/kernel split"
962 config VMSPLIT_3G_OPT
964 bool "3G/1G user/kernel split (for full 1G low memory)"
966 bool "2G/2G user/kernel split"
967 config VMSPLIT_2G_OPT
969 bool "2G/2G user/kernel split (for full 2G low memory)"
971 bool "1G/3G user/kernel split"
976 default 0xB0000000 if VMSPLIT_3G_OPT
977 default 0x80000000 if VMSPLIT_2G
978 default 0x78000000 if VMSPLIT_2G_OPT
979 default 0x40000000 if VMSPLIT_1G
985 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
988 bool "PAE (Physical Address Extension) Support"
989 depends on X86_32 && !HIGHMEM4G
991 PAE is required for NX support, and furthermore enables
992 larger swapspace support for non-overcommit purposes. It
993 has the cost of more pagetable lookup overhead, and also
994 consumes more pagetable space per process.
996 config ARCH_PHYS_ADDR_T_64BIT
997 def_bool X86_64 || X86_PAE
999 config DIRECT_GBPAGES
1000 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1004 Allow the kernel linear mapping to use 1GB pages on CPUs that
1005 support it. This can improve the kernel's performance a tiny bit by
1006 reducing TLB pressure. If in doubt, say "Y".
1008 # Common NUMA Features
1010 bool "Numa Memory Allocation and Scheduler Support"
1012 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1014 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1016 Enable NUMA (Non Uniform Memory Access) support.
1018 The kernel will try to allocate memory used by a CPU on the
1019 local memory controller of the CPU and add some more
1020 NUMA awareness to the kernel.
1022 For 64-bit this is recommended if the system is Intel Core i7
1023 (or later), AMD Opteron, or EM64T NUMA.
1025 For 32-bit this is only needed on (rare) 32-bit-only platforms
1026 that support NUMA topologies, such as NUMAQ / Summit, or if you
1027 boot a 32-bit kernel on a 64-bit NUMA platform.
1029 Otherwise, you should say N.
1031 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1032 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1036 prompt "Old style AMD Opteron NUMA detection"
1037 depends on X86_64 && NUMA && PCI
1039 Enable K8 NUMA node topology detection. You should say Y here if
1040 you have a multi processor AMD K8 system. This uses an old
1041 method to read the NUMA configuration directly from the builtin
1042 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1043 instead, which also takes priority if both are compiled in.
1045 config X86_64_ACPI_NUMA
1047 prompt "ACPI NUMA detection"
1048 depends on X86_64 && NUMA && ACPI && PCI
1051 Enable ACPI SRAT based node topology detection.
1053 # Some NUMA nodes have memory ranges that span
1054 # other nodes. Even though a pfn is valid and
1055 # between a node's start and end pfns, it may not
1056 # reside on that node. See memmap_init_zone()
1058 config NODES_SPAN_OTHER_NODES
1060 depends on X86_64_ACPI_NUMA
1063 bool "NUMA emulation"
1064 depends on X86_64 && NUMA
1066 Enable NUMA emulation. A flat machine will be split
1067 into virtual nodes when booted with "numa=fake=N", where N is the
1068 number of nodes. This is only useful for debugging.
1071 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1073 default "9" if MAXSMP
1074 default "6" if X86_64
1075 default "4" if X86_NUMAQ
1077 depends on NEED_MULTIPLE_NODES
1079 Specify the maximum number of NUMA Nodes available on the target
1080 system. Increases memory reserved to accomodate various tables.
1082 config HAVE_ARCH_BOOTMEM_NODE
1084 depends on X86_32 && NUMA
1086 config ARCH_HAVE_MEMORY_PRESENT
1088 depends on X86_32 && DISCONTIGMEM
1090 config NEED_NODE_MEMMAP_SIZE
1092 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1094 config HAVE_ARCH_ALLOC_REMAP
1096 depends on X86_32 && NUMA
1098 config ARCH_FLATMEM_ENABLE
1100 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1102 config ARCH_DISCONTIGMEM_ENABLE
1104 depends on NUMA && X86_32
1106 config ARCH_DISCONTIGMEM_DEFAULT
1108 depends on NUMA && X86_32
1110 config ARCH_SPARSEMEM_DEFAULT
1114 config ARCH_SPARSEMEM_ENABLE
1116 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1117 select SPARSEMEM_STATIC if X86_32
1118 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1120 config ARCH_SELECT_MEMORY_MODEL
1122 depends on ARCH_SPARSEMEM_ENABLE
1124 config ARCH_MEMORY_PROBE
1126 depends on MEMORY_HOTPLUG
1131 bool "Allocate 3rd-level pagetables from highmem"
1132 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1134 The VM uses one page table entry for each page of physical memory.
1135 For systems with a lot of RAM, this can be wasteful of precious
1136 low memory. Setting this option will put user-space page table
1137 entries in high memory.
1139 config X86_CHECK_BIOS_CORRUPTION
1140 bool "Check for low memory corruption"
1142 Periodically check for memory corruption in low memory, which
1143 is suspected to be caused by BIOS. Even when enabled in the
1144 configuration, it is disabled at runtime. Enable it by
1145 setting "memory_corruption_check=1" on the kernel command
1146 line. By default it scans the low 64k of memory every 60
1147 seconds; see the memory_corruption_check_size and
1148 memory_corruption_check_period parameters in
1149 Documentation/kernel-parameters.txt to adjust this.
1151 When enabled with the default parameters, this option has
1152 almost no overhead, as it reserves a relatively small amount
1153 of memory and scans it infrequently. It both detects corruption
1154 and prevents it from affecting the running system.
1156 It is, however, intended as a diagnostic tool; if repeatable
1157 BIOS-originated corruption always affects the same memory,
1158 you can use memmap= to prevent the kernel from using that
1161 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1162 bool "Set the default setting of memory_corruption_check"
1163 depends on X86_CHECK_BIOS_CORRUPTION
1166 Set whether the default state of memory_corruption_check is
1169 config X86_RESERVE_LOW_64K
1170 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1173 Reserve the first 64K of physical RAM on BIOSes that are known
1174 to potentially corrupt that memory range. A numbers of BIOSes are
1175 known to utilize this area during suspend/resume, so it must not
1176 be used by the kernel.
1178 Set this to N if you are absolutely sure that you trust the BIOS
1179 to get all its memory reservations and usages right.
1181 If you have doubts about the BIOS (e.g. suspend/resume does not
1182 work or there's kernel crashes after certain hardware hotplug
1183 events) and it's not AMI or Phoenix, then you might want to enable
1184 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1185 corruption patterns.
1189 config MATH_EMULATION
1191 prompt "Math emulation" if X86_32
1193 Linux can emulate a math coprocessor (used for floating point
1194 operations) if you don't have one. 486DX and Pentium processors have
1195 a math coprocessor built in, 486SX and 386 do not, unless you added
1196 a 487DX or 387, respectively. (The messages during boot time can
1197 give you some hints here ["man dmesg"].) Everyone needs either a
1198 coprocessor or this emulation.
1200 If you don't have a math coprocessor, you need to say Y here; if you
1201 say Y here even though you have a coprocessor, the coprocessor will
1202 be used nevertheless. (This behavior can be changed with the kernel
1203 command line option "no387", which comes handy if your coprocessor
1204 is broken. Try "man bootparam" or see the documentation of your boot
1205 loader (lilo or loadlin) about how to pass options to the kernel at
1206 boot time.) This means that it is a good idea to say Y here if you
1207 intend to use this kernel on different machines.
1209 More information about the internals of the Linux math coprocessor
1210 emulation can be found in <file:arch/x86/math-emu/README>.
1212 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1213 kernel, it won't hurt.
1216 bool "MTRR (Memory Type Range Register) support"
1218 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1219 the Memory Type Range Registers (MTRRs) may be used to control
1220 processor access to memory ranges. This is most useful if you have
1221 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1222 allows bus write transfers to be combined into a larger transfer
1223 before bursting over the PCI/AGP bus. This can increase performance
1224 of image write operations 2.5 times or more. Saying Y here creates a
1225 /proc/mtrr file which may be used to manipulate your processor's
1226 MTRRs. Typically the X server should use this.
1228 This code has a reasonably generic interface so that similar
1229 control registers on other processors can be easily supported
1232 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1233 Registers (ARRs) which provide a similar functionality to MTRRs. For
1234 these, the ARRs are used to emulate the MTRRs.
1235 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1236 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1237 write-combining. All of these processors are supported by this code
1238 and it makes sense to say Y here if you have one of them.
1240 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1241 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1242 can lead to all sorts of problems, so it's good to say Y here.
1244 You can safely say Y even if your machine doesn't have MTRRs, you'll
1245 just add about 9 KB to your kernel.
1247 See <file:Documentation/x86/mtrr.txt> for more information.
1249 config MTRR_SANITIZER
1251 prompt "MTRR cleanup support"
1254 Convert MTRR layout from continuous to discrete, so X drivers can
1255 add writeback entries.
1257 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1258 The largest mtrr entry size for a continous block can be set with
1263 config MTRR_SANITIZER_ENABLE_DEFAULT
1264 int "MTRR cleanup enable value (0-1)"
1267 depends on MTRR_SANITIZER
1269 Enable mtrr cleanup default value
1271 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1272 int "MTRR cleanup spare reg num (0-7)"
1275 depends on MTRR_SANITIZER
1277 mtrr cleanup spare entries default, it can be changed via
1278 mtrr_spare_reg_nr=N on the kernel command line.
1282 prompt "x86 PAT support"
1285 Use PAT attributes to setup page level cache control.
1287 PATs are the modern equivalents of MTRRs and are much more
1288 flexible than MTRRs.
1290 Say N here if you see bootup problems (boot crash, boot hang,
1291 spontaneous reboots) or a non-working video driver.
1296 bool "EFI runtime service support"
1299 This enables the kernel to use EFI runtime services that are
1300 available (such as the EFI variable services).
1302 This option is only useful on systems that have EFI firmware.
1303 In addition, you should use the latest ELILO loader available
1304 at <http://elilo.sourceforge.net> in order to take advantage
1305 of EFI runtime services. However, even with this option, the
1306 resultant kernel should continue to boot on existing non-EFI
1311 prompt "Enable seccomp to safely compute untrusted bytecode"
1313 This kernel feature is useful for number crunching applications
1314 that may need to compute untrusted bytecode during their
1315 execution. By using pipes or other transports made available to
1316 the process as file descriptors supporting the read/write
1317 syscalls, it's possible to isolate those applications in
1318 their own address space using seccomp. Once seccomp is
1319 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1320 and the task is only allowed to execute a few safe syscalls
1321 defined by each seccomp mode.
1323 If unsure, say Y. Only embedded should say N here.
1325 config CC_STACKPROTECTOR_ALL
1328 config CC_STACKPROTECTOR
1329 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1331 select CC_STACKPROTECTOR_ALL
1333 This option turns on the -fstack-protector GCC feature. This
1334 feature puts, at the beginning of functions, a canary value on
1335 the stack just before the return address, and validates
1336 the value just before actually returning. Stack based buffer
1337 overflows (that need to overwrite this return address) now also
1338 overwrite the canary, which gets detected and the attack is then
1339 neutralized via a kernel panic.
1341 This feature requires gcc version 4.2 or above, or a distribution
1342 gcc with the feature backported. Older versions are automatically
1343 detected and for those versions, this configuration option is
1344 ignored. (and a warning is printed during bootup)
1346 source kernel/Kconfig.hz
1349 bool "kexec system call"
1351 kexec is a system call that implements the ability to shutdown your
1352 current kernel, and to start another kernel. It is like a reboot
1353 but it is independent of the system firmware. And like a reboot
1354 you can start any kernel with it, not just Linux.
1356 The name comes from the similarity to the exec system call.
1358 It is an ongoing process to be certain the hardware in a machine
1359 is properly shutdown, so do not be surprised if this code does not
1360 initially work for you. It may help to enable device hotplugging
1361 support. As of this writing the exact hardware interface is
1362 strongly in flux, so no good recommendation can be made.
1365 bool "kernel crash dumps"
1366 depends on X86_64 || (X86_32 && HIGHMEM)
1368 Generate crash dump after being started by kexec.
1369 This should be normally only set in special crash dump kernels
1370 which are loaded in the main kernel with kexec-tools into
1371 a specially reserved region and then later executed after
1372 a crash by kdump/kexec. The crash dump kernel must be compiled
1373 to a memory address not used by the main kernel or BIOS using
1374 PHYSICAL_START, or it must be built as a relocatable image
1375 (CONFIG_RELOCATABLE=y).
1376 For more details see Documentation/kdump/kdump.txt
1379 bool "kexec jump (EXPERIMENTAL)"
1380 depends on EXPERIMENTAL
1381 depends on KEXEC && HIBERNATION && X86_32
1383 Jump between original kernel and kexeced kernel and invoke
1384 code in physical address mode via KEXEC
1386 config PHYSICAL_START
1387 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1388 default "0x1000000" if X86_NUMAQ
1389 default "0x200000" if X86_64
1392 This gives the physical address where the kernel is loaded.
1394 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1395 bzImage will decompress itself to above physical address and
1396 run from there. Otherwise, bzImage will run from the address where
1397 it has been loaded by the boot loader and will ignore above physical
1400 In normal kdump cases one does not have to set/change this option
1401 as now bzImage can be compiled as a completely relocatable image
1402 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1403 address. This option is mainly useful for the folks who don't want
1404 to use a bzImage for capturing the crash dump and want to use a
1405 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1406 to be specifically compiled to run from a specific memory area
1407 (normally a reserved region) and this option comes handy.
1409 So if you are using bzImage for capturing the crash dump, leave
1410 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1411 Otherwise if you plan to use vmlinux for capturing the crash dump
1412 change this value to start of the reserved region (Typically 16MB
1413 0x1000000). In other words, it can be set based on the "X" value as
1414 specified in the "crashkernel=YM@XM" command line boot parameter
1415 passed to the panic-ed kernel. Typically this parameter is set as
1416 crashkernel=64M@16M. Please take a look at
1417 Documentation/kdump/kdump.txt for more details about crash dumps.
1419 Usage of bzImage for capturing the crash dump is recommended as
1420 one does not have to build two kernels. Same kernel can be used
1421 as production kernel and capture kernel. Above option should have
1422 gone away after relocatable bzImage support is introduced. But it
1423 is present because there are users out there who continue to use
1424 vmlinux for dump capture. This option should go away down the
1427 Don't change this unless you know what you are doing.
1430 bool "Build a relocatable kernel (EXPERIMENTAL)"
1431 depends on EXPERIMENTAL
1433 This builds a kernel image that retains relocation information
1434 so it can be loaded someplace besides the default 1MB.
1435 The relocations tend to make the kernel binary about 10% larger,
1436 but are discarded at runtime.
1438 One use is for the kexec on panic case where the recovery kernel
1439 must live at a different physical address than the primary
1442 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1443 it has been loaded at and the compile time physical address
1444 (CONFIG_PHYSICAL_START) is ignored.
1446 config PHYSICAL_ALIGN
1448 prompt "Alignment value to which kernel should be aligned" if X86_32
1449 default "0x100000" if X86_32
1450 default "0x200000" if X86_64
1451 range 0x2000 0x400000
1453 This value puts the alignment restrictions on physical address
1454 where kernel is loaded and run from. Kernel is compiled for an
1455 address which meets above alignment restriction.
1457 If bootloader loads the kernel at a non-aligned address and
1458 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1459 address aligned to above value and run from there.
1461 If bootloader loads the kernel at a non-aligned address and
1462 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1463 load address and decompress itself to the address it has been
1464 compiled for and run from there. The address for which kernel is
1465 compiled already meets above alignment restrictions. Hence the
1466 end result is that kernel runs from a physical address meeting
1467 above alignment restrictions.
1469 Don't change this unless you know what you are doing.
1472 bool "Support for hot-pluggable CPUs"
1473 depends on SMP && HOTPLUG
1475 Say Y here to allow turning CPUs off and on. CPUs can be
1476 controlled through /sys/devices/system/cpu.
1477 ( Note: power management support will enable this option
1478 automatically on SMP systems. )
1479 Say N if you want to disable CPU hotplug.
1483 prompt "Compat VDSO support"
1484 depends on X86_32 || IA32_EMULATION
1486 Map the 32-bit VDSO to the predictable old-style address too.
1488 Say N here if you are running a sufficiently recent glibc
1489 version (2.3.3 or later), to remove the high-mapped
1490 VDSO mapping and to exclusively use the randomized VDSO.
1495 bool "Built-in kernel command line"
1498 Allow for specifying boot arguments to the kernel at
1499 build time. On some systems (e.g. embedded ones), it is
1500 necessary or convenient to provide some or all of the
1501 kernel boot arguments with the kernel itself (that is,
1502 to not rely on the boot loader to provide them.)
1504 To compile command line arguments into the kernel,
1505 set this option to 'Y', then fill in the
1506 the boot arguments in CONFIG_CMDLINE.
1508 Systems with fully functional boot loaders (i.e. non-embedded)
1509 should leave this option set to 'N'.
1512 string "Built-in kernel command string"
1513 depends on CMDLINE_BOOL
1516 Enter arguments here that should be compiled into the kernel
1517 image and used at boot time. If the boot loader provides a
1518 command line at boot time, it is appended to this string to
1519 form the full kernel command line, when the system boots.
1521 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1522 change this behavior.
1524 In most cases, the command line (whether built-in or provided
1525 by the boot loader) should specify the device for the root
1528 config CMDLINE_OVERRIDE
1529 bool "Built-in command line overrides boot loader arguments"
1531 depends on CMDLINE_BOOL
1533 Set this option to 'Y' to have the kernel ignore the boot loader
1534 command line, and use ONLY the built-in command line.
1536 This is used to work around broken boot loaders. This should
1537 be set to 'N' under normal conditions.
1541 config ARCH_ENABLE_MEMORY_HOTPLUG
1543 depends on X86_64 || (X86_32 && HIGHMEM)
1545 config ARCH_ENABLE_MEMORY_HOTREMOVE
1547 depends on MEMORY_HOTPLUG
1549 config HAVE_ARCH_EARLY_PFN_TO_NID
1553 menu "Power management and ACPI options"
1555 config ARCH_HIBERNATION_HEADER
1557 depends on X86_64 && HIBERNATION
1559 source "kernel/power/Kconfig"
1561 source "drivers/acpi/Kconfig"
1566 depends on APM || APM_MODULE
1569 tristate "APM (Advanced Power Management) BIOS support"
1570 depends on X86_32 && PM_SLEEP
1572 APM is a BIOS specification for saving power using several different
1573 techniques. This is mostly useful for battery powered laptops with
1574 APM compliant BIOSes. If you say Y here, the system time will be
1575 reset after a RESUME operation, the /proc/apm device will provide
1576 battery status information, and user-space programs will receive
1577 notification of APM "events" (e.g. battery status change).
1579 If you select "Y" here, you can disable actual use of the APM
1580 BIOS by passing the "apm=off" option to the kernel at boot time.
1582 Note that the APM support is almost completely disabled for
1583 machines with more than one CPU.
1585 In order to use APM, you will need supporting software. For location
1586 and more information, read <file:Documentation/power/pm.txt> and the
1587 Battery Powered Linux mini-HOWTO, available from
1588 <http://www.tldp.org/docs.html#howto>.
1590 This driver does not spin down disk drives (see the hdparm(8)
1591 manpage ("man 8 hdparm") for that), and it doesn't turn off
1592 VESA-compliant "green" monitors.
1594 This driver does not support the TI 4000M TravelMate and the ACER
1595 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1596 desktop machines also don't have compliant BIOSes, and this driver
1597 may cause those machines to panic during the boot phase.
1599 Generally, if you don't have a battery in your machine, there isn't
1600 much point in using this driver and you should say N. If you get
1601 random kernel OOPSes or reboots that don't seem to be related to
1602 anything, try disabling/enabling this option (or disabling/enabling
1605 Some other things you should try when experiencing seemingly random,
1608 1) make sure that you have enough swap space and that it is
1610 2) pass the "no-hlt" option to the kernel
1611 3) switch on floating point emulation in the kernel and pass
1612 the "no387" option to the kernel
1613 4) pass the "floppy=nodma" option to the kernel
1614 5) pass the "mem=4M" option to the kernel (thereby disabling
1615 all but the first 4 MB of RAM)
1616 6) make sure that the CPU is not over clocked.
1617 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1618 8) disable the cache from your BIOS settings
1619 9) install a fan for the video card or exchange video RAM
1620 10) install a better fan for the CPU
1621 11) exchange RAM chips
1622 12) exchange the motherboard.
1624 To compile this driver as a module, choose M here: the
1625 module will be called apm.
1629 config APM_IGNORE_USER_SUSPEND
1630 bool "Ignore USER SUSPEND"
1632 This option will ignore USER SUSPEND requests. On machines with a
1633 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1634 series notebooks, it is necessary to say Y because of a BIOS bug.
1636 config APM_DO_ENABLE
1637 bool "Enable PM at boot time"
1639 Enable APM features at boot time. From page 36 of the APM BIOS
1640 specification: "When disabled, the APM BIOS does not automatically
1641 power manage devices, enter the Standby State, enter the Suspend
1642 State, or take power saving steps in response to CPU Idle calls."
1643 This driver will make CPU Idle calls when Linux is idle (unless this
1644 feature is turned off -- see "Do CPU IDLE calls", below). This
1645 should always save battery power, but more complicated APM features
1646 will be dependent on your BIOS implementation. You may need to turn
1647 this option off if your computer hangs at boot time when using APM
1648 support, or if it beeps continuously instead of suspending. Turn
1649 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1650 T400CDT. This is off by default since most machines do fine without
1654 bool "Make CPU Idle calls when idle"
1656 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1657 On some machines, this can activate improved power savings, such as
1658 a slowed CPU clock rate, when the machine is idle. These idle calls
1659 are made after the idle loop has run for some length of time (e.g.,
1660 333 mS). On some machines, this will cause a hang at boot time or
1661 whenever the CPU becomes idle. (On machines with more than one CPU,
1662 this option does nothing.)
1664 config APM_DISPLAY_BLANK
1665 bool "Enable console blanking using APM"
1667 Enable console blanking using the APM. Some laptops can use this to
1668 turn off the LCD backlight when the screen blanker of the Linux
1669 virtual console blanks the screen. Note that this is only used by
1670 the virtual console screen blanker, and won't turn off the backlight
1671 when using the X Window system. This also doesn't have anything to
1672 do with your VESA-compliant power-saving monitor. Further, this
1673 option doesn't work for all laptops -- it might not turn off your
1674 backlight at all, or it might print a lot of errors to the console,
1675 especially if you are using gpm.
1677 config APM_ALLOW_INTS
1678 bool "Allow interrupts during APM BIOS calls"
1680 Normally we disable external interrupts while we are making calls to
1681 the APM BIOS as a measure to lessen the effects of a badly behaving
1682 BIOS implementation. The BIOS should reenable interrupts if it
1683 needs to. Unfortunately, some BIOSes do not -- especially those in
1684 many of the newer IBM Thinkpads. If you experience hangs when you
1685 suspend, try setting this to Y. Otherwise, say N.
1689 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1691 source "drivers/cpuidle/Kconfig"
1693 source "drivers/idle/Kconfig"
1698 menu "Bus options (PCI etc.)"
1703 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1705 Find out whether you have a PCI motherboard. PCI is the name of a
1706 bus system, i.e. the way the CPU talks to the other stuff inside
1707 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1708 VESA. If you have PCI, say Y, otherwise N.
1711 prompt "PCI access mode"
1712 depends on X86_32 && PCI
1715 On PCI systems, the BIOS can be used to detect the PCI devices and
1716 determine their configuration. However, some old PCI motherboards
1717 have BIOS bugs and may crash if this is done. Also, some embedded
1718 PCI-based systems don't have any BIOS at all. Linux can also try to
1719 detect the PCI hardware directly without using the BIOS.
1721 With this option, you can specify how Linux should detect the
1722 PCI devices. If you choose "BIOS", the BIOS will be used,
1723 if you choose "Direct", the BIOS won't be used, and if you
1724 choose "MMConfig", then PCI Express MMCONFIG will be used.
1725 If you choose "Any", the kernel will try MMCONFIG, then the
1726 direct access method and falls back to the BIOS if that doesn't
1727 work. If unsure, go with the default, which is "Any".
1732 config PCI_GOMMCONFIG
1749 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1751 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1754 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1758 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1762 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1769 bool "Support mmconfig PCI config space access"
1770 depends on X86_64 && PCI && ACPI
1773 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1774 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1776 DMA remapping (DMAR) devices support enables independent address
1777 translations for Direct Memory Access (DMA) from devices.
1778 These DMA remapping devices are reported via ACPI tables
1779 and include PCI device scope covered by these DMA
1784 prompt "Support for Graphics workaround"
1787 Current Graphics drivers tend to use physical address
1788 for DMA and avoid using DMA APIs. Setting this config
1789 option permits the IOMMU driver to set a unity map for
1790 all the OS-visible memory. Hence the driver can continue
1791 to use physical addresses for DMA.
1793 config DMAR_FLOPPY_WA
1797 Floppy disk drivers are know to bypass DMA API calls
1798 thereby failing to work when IOMMU is enabled. This
1799 workaround will setup a 1:1 mapping for the first
1800 16M to make floppy (an ISA device) work.
1803 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1804 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1806 Supports Interrupt remapping for IO-APIC and MSI devices.
1807 To use x2apic mode in the CPU's which support x2APIC enhancements or
1808 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1810 source "drivers/pci/pcie/Kconfig"
1812 source "drivers/pci/Kconfig"
1814 # x86_64 have no ISA slots, but do have ISA-style DMA.
1822 depends on !X86_VOYAGER
1824 Find out whether you have ISA slots on your motherboard. ISA is the
1825 name of a bus system, i.e. the way the CPU talks to the other stuff
1826 inside your box. Other bus systems are PCI, EISA, MicroChannel
1827 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1828 newer boards don't support it. If you have ISA, say Y, otherwise N.
1834 The Extended Industry Standard Architecture (EISA) bus was
1835 developed as an open alternative to the IBM MicroChannel bus.
1837 The EISA bus provided some of the features of the IBM MicroChannel
1838 bus while maintaining backward compatibility with cards made for
1839 the older ISA bus. The EISA bus saw limited use between 1988 and
1840 1995 when it was made obsolete by the PCI bus.
1842 Say Y here if you are building a kernel for an EISA-based machine.
1846 source "drivers/eisa/Kconfig"
1851 MicroChannel Architecture is found in some IBM PS/2 machines and
1852 laptops. It is a bus system similar to PCI or ISA. See
1853 <file:Documentation/mca.txt> (and especially the web page given
1854 there) before attempting to build an MCA bus kernel.
1856 source "drivers/mca/Kconfig"
1859 tristate "NatSemi SCx200 support"
1861 This provides basic support for National Semiconductor's
1862 (now AMD's) Geode processors. The driver probes for the
1863 PCI-IDs of several on-chip devices, so its a good dependency
1864 for other scx200_* drivers.
1866 If compiled as a module, the driver is named scx200.
1868 config SCx200HR_TIMER
1869 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1870 depends on SCx200 && GENERIC_TIME
1873 This driver provides a clocksource built upon the on-chip
1874 27MHz high-resolution timer. Its also a workaround for
1875 NSC Geode SC-1100's buggy TSC, which loses time when the
1876 processor goes idle (as is done by the scheduler). The
1877 other workaround is idle=poll boot option.
1879 config GEODE_MFGPT_TIMER
1881 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1882 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1884 This driver provides a clock event source based on the MFGPT
1885 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1886 MFGPTs have a better resolution and max interval than the
1887 generic PIT, and are suitable for use as high-res timers.
1890 bool "One Laptop Per Child support"
1893 Add support for detecting the unique features of the OLPC
1900 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1902 source "drivers/pcmcia/Kconfig"
1904 source "drivers/pci/hotplug/Kconfig"
1909 menu "Executable file formats / Emulations"
1911 source "fs/Kconfig.binfmt"
1913 config IA32_EMULATION
1914 bool "IA32 Emulation"
1916 select COMPAT_BINFMT_ELF
1918 Include code to run 32-bit programs under a 64-bit kernel. You should
1919 likely turn this on, unless you're 100% sure that you don't have any
1920 32-bit programs left.
1923 tristate "IA32 a.out support"
1924 depends on IA32_EMULATION
1926 Support old a.out binaries in the 32bit emulation.
1930 depends on IA32_EMULATION
1932 config COMPAT_FOR_U64_ALIGNMENT
1936 config SYSVIPC_COMPAT
1938 depends on COMPAT && SYSVIPC
1943 config HAVE_ATOMIC_IOMAP
1947 source "net/Kconfig"
1949 source "drivers/Kconfig"
1951 source "drivers/firmware/Kconfig"
1955 source "arch/x86/Kconfig.debug"
1957 source "security/Kconfig"
1959 source "crypto/Kconfig"
1961 source "arch/x86/kvm/Kconfig"
1963 source "lib/Kconfig"
projects / linux-2.6 / blob