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
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_FTRACE_SYSCALLS
41 select HAVE_ARCH_TRACEHOOK
42 select HAVE_GENERIC_DMA_COHERENT if X86_32
43 select HAVE_EFFICIENT_UNALIGNED_ACCESS
44 select USER_STACKTRACE_SUPPORT
45 select HAVE_DMA_API_DEBUG
46 select HAVE_KERNEL_GZIP
47 select HAVE_KERNEL_BZIP2
48 select HAVE_KERNEL_LZMA
52 default "arch/x86/configs/i386_defconfig" if X86_32
53 default "arch/x86/configs/x86_64_defconfig" if X86_64
58 config GENERIC_CMOS_UPDATE
61 config CLOCKSOURCE_WATCHDOG
64 config GENERIC_CLOCKEVENTS
67 config GENERIC_CLOCKEVENTS_BROADCAST
69 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
71 config LOCKDEP_SUPPORT
74 config STACKTRACE_SUPPORT
77 config HAVE_LATENCYTOP_SUPPORT
80 config FAST_CMPXCHG_LOCAL
93 config GENERIC_ISA_DMA
102 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
104 config GENERIC_BUG_RELATIVE_POINTERS
107 config GENERIC_HWEIGHT
113 config ARCH_MAY_HAVE_PC_FDC
116 config RWSEM_GENERIC_SPINLOCK
119 config RWSEM_XCHGADD_ALGORITHM
122 config ARCH_HAS_CPU_IDLE_WAIT
125 config GENERIC_CALIBRATE_DELAY
128 config GENERIC_TIME_VSYSCALL
132 config ARCH_HAS_CPU_RELAX
135 config ARCH_HAS_DEFAULT_IDLE
138 config ARCH_HAS_CACHE_LINE_SIZE
141 config HAVE_SETUP_PER_CPU_AREA
144 config HAVE_DYNAMIC_PER_CPU_AREA
147 config HAVE_CPUMASK_OF_CPU_MAP
150 config ARCH_HIBERNATION_POSSIBLE
153 config ARCH_SUSPEND_POSSIBLE
160 config ARCH_POPULATES_NODE_MAP
167 config ARCH_SUPPORTS_OPTIMIZED_INLINING
170 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
173 # Use the generic interrupt handling code in kernel/irq/:
174 config GENERIC_HARDIRQS
178 config GENERIC_HARDIRQS_NO__DO_IRQ
181 config GENERIC_IRQ_PROBE
185 config GENERIC_PENDING_IRQ
187 depends on GENERIC_HARDIRQS && SMP
190 config USE_GENERIC_SMP_HELPERS
196 depends on X86_32 && SMP
200 depends on X86_64 && SMP
207 config X86_TRAMPOLINE
209 depends on SMP || (64BIT && ACPI_SLEEP)
212 config X86_32_LAZY_GS
214 depends on X86_32 && !CC_STACKPROTECTOR
218 source "init/Kconfig"
219 source "kernel/Kconfig.freezer"
221 menu "Processor type and features"
223 source "kernel/time/Kconfig"
226 bool "Symmetric multi-processing support"
228 This enables support for systems with more than one CPU. If you have
229 a system with only one CPU, like most personal computers, say N. If
230 you have a system with more than one CPU, say Y.
232 If you say N here, the kernel will run on single and multiprocessor
233 machines, but will use only one CPU of a multiprocessor machine. If
234 you say Y here, the kernel will run on many, but not all,
235 singleprocessor machines. On a singleprocessor machine, the kernel
236 will run faster if you say N here.
238 Note that if you say Y here and choose architecture "586" or
239 "Pentium" under "Processor family", the kernel will not work on 486
240 architectures. Similarly, multiprocessor kernels for the "PPro"
241 architecture may not work on all Pentium based boards.
243 People using multiprocessor machines who say Y here should also say
244 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
245 Management" code will be disabled if you say Y here.
247 See also <file:Documentation/i386/IO-APIC.txt>,
248 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
249 <http://www.tldp.org/docs.html#howto>.
251 If you don't know what to do here, say N.
254 bool "Support x2apic"
255 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
257 This enables x2apic support on CPUs that have this feature.
259 This allows 32-bit apic IDs (so it can support very large systems),
260 and accesses the local apic via MSRs not via mmio.
262 If you don't know what to do here, say N.
265 bool "Support sparse irq numbering"
266 depends on PCI_MSI || HT_IRQ
268 This enables support for sparse irqs. This is useful for distro
269 kernels that want to define a high CONFIG_NR_CPUS value but still
270 want to have low kernel memory footprint on smaller machines.
272 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
273 out the irq_desc[] array in a more NUMA-friendly way. )
275 If you don't know what to do here, say N.
277 config NUMA_MIGRATE_IRQ_DESC
278 bool "Move irq desc when changing irq smp_affinity"
279 depends on SPARSE_IRQ && NUMA
283 This enables moving irq_desc to cpu/node that irq will use handled.
285 If you don't know what to do here, say N.
288 bool "Enable MPS table" if ACPI
290 depends on X86_LOCAL_APIC
292 For old smp systems that do not have proper acpi support. Newer systems
293 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
296 bool "Support for big SMP systems with more than 8 CPUs"
297 depends on X86_32 && SMP
299 This option is needed for the systems that have more than 8 CPUs
302 config X86_EXTENDED_PLATFORM
303 bool "Support for extended (non-PC) x86 platforms"
306 If you disable this option then the kernel will only support
307 standard PC platforms. (which covers the vast majority of
310 If you enable this option then you'll be able to select support
311 for the following (non-PC) 32 bit x86 platforms:
315 SGI 320/540 (Visual Workstation)
316 Summit/EXA (IBM x440)
317 Unisys ES7000 IA32 series
319 If you have one of these systems, or if you want to build a
320 generic distribution kernel, say Y here - otherwise say N.
324 config X86_EXTENDED_PLATFORM
325 bool "Support for extended (non-PC) x86 platforms"
328 If you disable this option then the kernel will only support
329 standard PC platforms. (which covers the vast majority of
332 If you enable this option then you'll be able to select support
333 for the following (non-PC) 64 bit x86 platforms:
337 If you have one of these systems, or if you want to build a
338 generic distribution kernel, say Y here - otherwise say N.
340 # This is an alphabetically sorted list of 64 bit extended platforms
341 # Please maintain the alphabetic order if and when there are additions
346 depends on X86_64 && PCI
347 depends on X86_EXTENDED_PLATFORM
349 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
350 supposed to run on these EM64T-based machines. Only choose this option
351 if you have one of these machines.
354 bool "SGI Ultraviolet"
356 depends on X86_EXTENDED_PLATFORM
360 This option is needed in order to support SGI Ultraviolet systems.
361 If you don't have one of these, you should say N here.
363 # Following is an alphabetically sorted list of 32 bit extended platforms
364 # Please maintain the alphabetic order if and when there are additions
369 depends on X86_EXTENDED_PLATFORM
371 Select this for an AMD Elan processor.
373 Do not use this option for K6/Athlon/Opteron processors!
375 If unsure, choose "PC-compatible" instead.
378 bool "RDC R-321x SoC"
380 depends on X86_EXTENDED_PLATFORM
382 select X86_REBOOTFIXUPS
384 This option is needed for RDC R-321x system-on-chip, also known
386 If you don't have one of these chips, you should say N here.
388 config X86_32_NON_STANDARD
389 bool "Support non-standard 32-bit SMP architectures"
390 depends on X86_32 && SMP
391 depends on X86_EXTENDED_PLATFORM
393 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
394 subarchitectures. It is intended for a generic binary kernel.
395 if you select them all, kernel will probe it one by one. and will
398 # Alphabetically sorted list of Non standard 32 bit platforms
401 bool "NUMAQ (IBM/Sequent)"
402 depends on X86_32_NON_STANDARD
406 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
407 NUMA multiquad box. This changes the way that processors are
408 bootstrapped, and uses Clustered Logical APIC addressing mode instead
409 of Flat Logical. You will need a new lynxer.elf file to flash your
410 firmware with - send email to <Martin.Bligh@us.ibm.com>.
413 bool "SGI 320/540 (Visual Workstation)"
414 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
415 depends on X86_32_NON_STANDARD
417 The SGI Visual Workstation series is an IA32-based workstation
418 based on SGI systems chips with some legacy PC hardware attached.
420 Say Y here to create a kernel to run on the SGI 320 or 540.
422 A kernel compiled for the Visual Workstation will run on general
423 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
426 bool "Summit/EXA (IBM x440)"
427 depends on X86_32_NON_STANDARD
429 This option is needed for IBM systems that use the Summit/EXA chipset.
430 In particular, it is needed for the x440.
433 bool "Unisys ES7000 IA32 series"
434 depends on X86_32_NON_STANDARD && X86_BIGSMP
436 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
437 supposed to run on an IA32-based Unisys ES7000 system.
439 config SCHED_OMIT_FRAME_POINTER
441 prompt "Single-depth WCHAN output"
444 Calculate simpler /proc/<PID>/wchan values. If this option
445 is disabled then wchan values will recurse back to the
446 caller function. This provides more accurate wchan values,
447 at the expense of slightly more scheduling overhead.
449 If in doubt, say "Y".
451 menuconfig PARAVIRT_GUEST
452 bool "Paravirtualized guest support"
454 Say Y here to get to see options related to running Linux under
455 various hypervisors. This option alone does not add any kernel code.
457 If you say N, all options in this submenu will be skipped and disabled.
461 source "arch/x86/xen/Kconfig"
464 bool "VMI Guest support"
468 VMI provides a paravirtualized interface to the VMware ESX server
469 (it could be used by other hypervisors in theory too, but is not
470 at the moment), by linking the kernel to a GPL-ed ROM module
471 provided by the hypervisor.
474 bool "KVM paravirtualized clock"
476 select PARAVIRT_CLOCK
478 Turning on this option will allow you to run a paravirtualized clock
479 when running over the KVM hypervisor. Instead of relying on a PIT
480 (or probably other) emulation by the underlying device model, the host
481 provides the guest with timing infrastructure such as time of day, and
485 bool "KVM Guest support"
488 This option enables various optimizations for running under the KVM
491 source "arch/x86/lguest/Kconfig"
494 bool "Enable paravirtualization code"
496 This changes the kernel so it can modify itself when it is run
497 under a hypervisor, potentially improving performance significantly
498 over full virtualization. However, when run without a hypervisor
499 the kernel is theoretically slower and slightly larger.
501 config PARAVIRT_SPINLOCKS
502 bool "Paravirtualization layer for spinlocks"
503 depends on PARAVIRT && SMP && EXPERIMENTAL
505 Paravirtualized spinlocks allow a pvops backend to replace the
506 spinlock implementation with something virtualization-friendly
507 (for example, block the virtual CPU rather than spinning).
509 Unfortunately the downside is an up to 5% performance hit on
510 native kernels, with various workloads.
512 If you are unsure how to answer this question, answer N.
514 config PARAVIRT_CLOCK
520 config PARAVIRT_DEBUG
521 bool "paravirt-ops debugging"
522 depends on PARAVIRT && DEBUG_KERNEL
524 Enable to debug paravirt_ops internals. Specifically, BUG if
525 a paravirt_op is missing when it is called.
530 This option adds a kernel parameter 'memtest', which allows memtest
532 memtest=0, mean disabled; -- default
533 memtest=1, mean do 1 test pattern;
535 memtest=4, mean do 4 test patterns.
536 If you are unsure how to answer this question, answer N.
538 config X86_SUMMIT_NUMA
540 depends on X86_32 && NUMA && X86_32_NON_STANDARD
542 config X86_CYCLONE_TIMER
544 depends on X86_32_NON_STANDARD
546 source "arch/x86/Kconfig.cpu"
550 prompt "HPET Timer Support" if X86_32
552 Use the IA-PC HPET (High Precision Event Timer) to manage
553 time in preference to the PIT and RTC, if a HPET is
555 HPET is the next generation timer replacing legacy 8254s.
556 The HPET provides a stable time base on SMP
557 systems, unlike the TSC, but it is more expensive to access,
558 as it is off-chip. You can find the HPET spec at
559 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
561 You can safely choose Y here. However, HPET will only be
562 activated if the platform and the BIOS support this feature.
563 Otherwise the 8254 will be used for timing services.
565 Choose N to continue using the legacy 8254 timer.
567 config HPET_EMULATE_RTC
569 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
571 # Mark as embedded because too many people got it wrong.
572 # The code disables itself when not needed.
575 bool "Enable DMI scanning" if EMBEDDED
577 Enabled scanning of DMI to identify machine quirks. Say Y
578 here unless you have verified that your setup is not
579 affected by entries in the DMI blacklist. Required by PNP
583 bool "GART IOMMU support" if EMBEDDED
587 depends on X86_64 && PCI
589 Support for full DMA access of devices with 32bit memory access only
590 on systems with more than 3GB. This is usually needed for USB,
591 sound, many IDE/SATA chipsets and some other devices.
592 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
593 based hardware IOMMU and a software bounce buffer based IOMMU used
594 on Intel systems and as fallback.
595 The code is only active when needed (enough memory and limited
596 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
600 bool "IBM Calgary IOMMU support"
602 depends on X86_64 && PCI && EXPERIMENTAL
604 Support for hardware IOMMUs in IBM's xSeries x366 and x460
605 systems. Needed to run systems with more than 3GB of memory
606 properly with 32-bit PCI devices that do not support DAC
607 (Double Address Cycle). Calgary also supports bus level
608 isolation, where all DMAs pass through the IOMMU. This
609 prevents them from going anywhere except their intended
610 destination. This catches hard-to-find kernel bugs and
611 mis-behaving drivers and devices that do not use the DMA-API
612 properly to set up their DMA buffers. The IOMMU can be
613 turned off at boot time with the iommu=off parameter.
614 Normally the kernel will make the right choice by itself.
617 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
619 prompt "Should Calgary be enabled by default?"
620 depends on CALGARY_IOMMU
622 Should Calgary be enabled by default? if you choose 'y', Calgary
623 will be used (if it exists). If you choose 'n', Calgary will not be
624 used even if it exists. If you choose 'n' and would like to use
625 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
629 bool "AMD IOMMU support"
632 depends on X86_64 && PCI && ACPI
634 With this option you can enable support for AMD IOMMU hardware in
635 your system. An IOMMU is a hardware component which provides
636 remapping of DMA memory accesses from devices. With an AMD IOMMU you
637 can isolate the the DMA memory of different devices and protect the
638 system from misbehaving device drivers or hardware.
640 You can find out if your system has an AMD IOMMU if you look into
641 your BIOS for an option to enable it or if you have an IVRS ACPI
644 config AMD_IOMMU_STATS
645 bool "Export AMD IOMMU statistics to debugfs"
649 This option enables code in the AMD IOMMU driver to collect various
650 statistics about whats happening in the driver and exports that
651 information to userspace via debugfs.
654 # need this always selected by IOMMU for the VIA workaround
658 Support for software bounce buffers used on x86-64 systems
659 which don't have a hardware IOMMU (e.g. the current generation
660 of Intel's x86-64 CPUs). Using this PCI devices which can only
661 access 32-bits of memory can be used on systems with more than
662 3 GB of memory. If unsure, say Y.
665 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
668 def_bool (AMD_IOMMU || DMAR)
671 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
672 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
673 select CPUMASK_OFFSTACK
676 Configure maximum number of CPUS and NUMA Nodes for this architecture.
680 int "Maximum number of CPUs" if SMP && !MAXSMP
681 range 2 8 if SMP && X86_32 && !X86_BIGSMP
682 range 2 512 if SMP && !MAXSMP
684 default "4096" if MAXSMP
685 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
688 This allows you to specify the maximum number of CPUs which this
689 kernel will support. The maximum supported value is 512 and the
690 minimum value which makes sense is 2.
692 This is purely to save memory - each supported CPU adds
693 approximately eight kilobytes to the kernel image.
696 bool "SMT (Hyperthreading) scheduler support"
699 SMT scheduler support improves the CPU scheduler's decision making
700 when dealing with Intel Pentium 4 chips with HyperThreading at a
701 cost of slightly increased overhead in some places. If unsure say
706 prompt "Multi-core scheduler support"
709 Multi-core scheduler support improves the CPU scheduler's decision
710 making when dealing with multi-core CPU chips at a cost of slightly
711 increased overhead in some places. If unsure say N here.
713 source "kernel/Kconfig.preempt"
716 bool "Local APIC support on uniprocessors"
717 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
719 A local APIC (Advanced Programmable Interrupt Controller) is an
720 integrated interrupt controller in the CPU. If you have a single-CPU
721 system which has a processor with a local APIC, you can say Y here to
722 enable and use it. If you say Y here even though your machine doesn't
723 have a local APIC, then the kernel will still run with no slowdown at
724 all. The local APIC supports CPU-generated self-interrupts (timer,
725 performance counters), and the NMI watchdog which detects hard
729 bool "IO-APIC support on uniprocessors"
730 depends on X86_UP_APIC
732 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
733 SMP-capable replacement for PC-style interrupt controllers. Most
734 SMP systems and many recent uniprocessor systems have one.
736 If you have a single-CPU system with an IO-APIC, you can say Y here
737 to use it. If you say Y here even though your machine doesn't have
738 an IO-APIC, then the kernel will still run with no slowdown at all.
740 config X86_LOCAL_APIC
742 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
746 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
748 config X86_VISWS_APIC
750 depends on X86_32 && X86_VISWS
752 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
753 bool "Reroute for broken boot IRQs"
755 depends on X86_IO_APIC
757 This option enables a workaround that fixes a source of
758 spurious interrupts. This is recommended when threaded
759 interrupt handling is used on systems where the generation of
760 superfluous "boot interrupts" cannot be disabled.
762 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
763 entry in the chipset's IO-APIC is masked (as, e.g. the RT
764 kernel does during interrupt handling). On chipsets where this
765 boot IRQ generation cannot be disabled, this workaround keeps
766 the original IRQ line masked so that only the equivalent "boot
767 IRQ" is delivered to the CPUs. The workaround also tells the
768 kernel to set up the IRQ handler on the boot IRQ line. In this
769 way only one interrupt is delivered to the kernel. Otherwise
770 the spurious second interrupt may cause the kernel to bring
771 down (vital) interrupt lines.
773 Only affects "broken" chipsets. Interrupt sharing may be
774 increased on these systems.
777 bool "Machine Check Exception"
779 Machine Check Exception support allows the processor to notify the
780 kernel if it detects a problem (e.g. overheating, component failure).
781 The action the kernel takes depends on the severity of the problem,
782 ranging from a warning message on the console, to halting the machine.
783 Your processor must be a Pentium or newer to support this - check the
784 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
785 have a design flaw which leads to false MCE events - hence MCE is
786 disabled on all P5 processors, unless explicitly enabled with "mce"
787 as a boot argument. Similarly, if MCE is built in and creates a
788 problem on some new non-standard machine, you can boot with "nomce"
789 to disable it. MCE support simply ignores non-MCE processors like
790 the 386 and 486, so nearly everyone can say Y here.
794 prompt "Intel MCE features"
795 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
797 Additional support for intel specific MCE features such as
802 prompt "AMD MCE features"
803 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
805 Additional support for AMD specific MCE features such as
806 the DRAM Error Threshold.
808 config X86_MCE_THRESHOLD
809 depends on X86_MCE_AMD || X86_MCE_INTEL
813 config X86_MCE_NONFATAL
814 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
815 depends on X86_32 && X86_MCE
817 Enabling this feature starts a timer that triggers every 5 seconds which
818 will look at the machine check registers to see if anything happened.
819 Non-fatal problems automatically get corrected (but still logged).
820 Disable this if you don't want to see these messages.
821 Seeing the messages this option prints out may be indicative of dying
822 or out-of-spec (ie, overclocked) hardware.
823 This option only does something on certain CPUs.
824 (AMD Athlon/Duron and Intel Pentium 4)
826 config X86_MCE_P4THERMAL
827 bool "check for P4 thermal throttling interrupt."
828 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
830 Enabling this feature will cause a message to be printed when the P4
831 enters thermal throttling.
834 bool "Enable VM86 support" if EMBEDDED
838 This option is required by programs like DOSEMU to run 16-bit legacy
839 code on X86 processors. It also may be needed by software like
840 XFree86 to initialize some video cards via BIOS. Disabling this
841 option saves about 6k.
844 tristate "Toshiba Laptop support"
847 This adds a driver to safely access the System Management Mode of
848 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
849 not work on models with a Phoenix BIOS. The System Management Mode
850 is used to set the BIOS and power saving options on Toshiba portables.
852 For information on utilities to make use of this driver see the
853 Toshiba Linux utilities web site at:
854 <http://www.buzzard.org.uk/toshiba/>.
856 Say Y if you intend to run this kernel on a Toshiba portable.
860 tristate "Dell laptop support"
862 This adds a driver to safely access the System Management Mode
863 of the CPU on the Dell Inspiron 8000. The System Management Mode
864 is used to read cpu temperature and cooling fan status and to
865 control the fans on the I8K portables.
867 This driver has been tested only on the Inspiron 8000 but it may
868 also work with other Dell laptops. You can force loading on other
869 models by passing the parameter `force=1' to the module. Use at
872 For information on utilities to make use of this driver see the
873 I8K Linux utilities web site at:
874 <http://people.debian.org/~dz/i8k/>
876 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
879 config X86_REBOOTFIXUPS
880 bool "Enable X86 board specific fixups for reboot"
883 This enables chipset and/or board specific fixups to be done
884 in order to get reboot to work correctly. This is only needed on
885 some combinations of hardware and BIOS. The symptom, for which
886 this config is intended, is when reboot ends with a stalled/hung
889 Currently, the only fixup is for the Geode machines using
890 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
892 Say Y if you want to enable the fixup. Currently, it's safe to
893 enable this option even if you don't need it.
897 tristate "/dev/cpu/microcode - microcode support"
900 If you say Y here, you will be able to update the microcode on
901 certain Intel and AMD processors. The Intel support is for the
902 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
903 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
904 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
905 You will obviously need the actual microcode binary data itself
906 which is not shipped with the Linux kernel.
908 This option selects the general module only, you need to select
909 at least one vendor specific module as well.
911 To compile this driver as a module, choose M here: the
912 module will be called microcode.
914 config MICROCODE_INTEL
915 bool "Intel microcode patch loading support"
920 This options enables microcode patch loading support for Intel
923 For latest news and information on obtaining all the required
924 Intel ingredients for this driver, check:
925 <http://www.urbanmyth.org/microcode/>.
928 bool "AMD microcode patch loading support"
932 If you select this option, microcode patch loading support for AMD
933 processors will be enabled.
935 config MICROCODE_OLD_INTERFACE
940 tristate "/dev/cpu/*/msr - Model-specific register support"
942 This device gives privileged processes access to the x86
943 Model-Specific Registers (MSRs). It is a character device with
944 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
945 MSR accesses are directed to a specific CPU on multi-processor
949 tristate "/dev/cpu/*/cpuid - CPU information support"
951 This device gives processes access to the x86 CPUID instruction to
952 be executed on a specific processor. It is a character device
953 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
957 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
959 If you select this option, this will provide various x86 CPUs
960 information through debugfs.
963 prompt "High Memory Support"
964 default HIGHMEM4G if !X86_NUMAQ
965 default HIGHMEM64G if X86_NUMAQ
970 depends on !X86_NUMAQ
972 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
973 However, the address space of 32-bit x86 processors is only 4
974 Gigabytes large. That means that, if you have a large amount of
975 physical memory, not all of it can be "permanently mapped" by the
976 kernel. The physical memory that's not permanently mapped is called
979 If you are compiling a kernel which will never run on a machine with
980 more than 1 Gigabyte total physical RAM, answer "off" here (default
981 choice and suitable for most users). This will result in a "3GB/1GB"
982 split: 3GB are mapped so that each process sees a 3GB virtual memory
983 space and the remaining part of the 4GB virtual memory space is used
984 by the kernel to permanently map as much physical memory as
987 If the machine has between 1 and 4 Gigabytes physical RAM, then
990 If more than 4 Gigabytes is used then answer "64GB" here. This
991 selection turns Intel PAE (Physical Address Extension) mode on.
992 PAE implements 3-level paging on IA32 processors. PAE is fully
993 supported by Linux, PAE mode is implemented on all recent Intel
994 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
995 then the kernel will not boot on CPUs that don't support PAE!
997 The actual amount of total physical memory will either be
998 auto detected or can be forced by using a kernel command line option
999 such as "mem=256M". (Try "man bootparam" or see the documentation of
1000 your boot loader (lilo or loadlin) about how to pass options to the
1001 kernel at boot time.)
1003 If unsure, say "off".
1007 depends on !X86_NUMAQ
1009 Select this if you have a 32-bit processor and between 1 and 4
1010 gigabytes of physical RAM.
1014 depends on !M386 && !M486
1017 Select this if you have a 32-bit processor and more than 4
1018 gigabytes of physical RAM.
1023 depends on EXPERIMENTAL
1024 prompt "Memory split" if EMBEDDED
1028 Select the desired split between kernel and user memory.
1030 If the address range available to the kernel is less than the
1031 physical memory installed, the remaining memory will be available
1032 as "high memory". Accessing high memory is a little more costly
1033 than low memory, as it needs to be mapped into the kernel first.
1034 Note that increasing the kernel address space limits the range
1035 available to user programs, making the address space there
1036 tighter. Selecting anything other than the default 3G/1G split
1037 will also likely make your kernel incompatible with binary-only
1040 If you are not absolutely sure what you are doing, leave this
1044 bool "3G/1G user/kernel split"
1045 config VMSPLIT_3G_OPT
1047 bool "3G/1G user/kernel split (for full 1G low memory)"
1049 bool "2G/2G user/kernel split"
1050 config VMSPLIT_2G_OPT
1052 bool "2G/2G user/kernel split (for full 2G low memory)"
1054 bool "1G/3G user/kernel split"
1059 default 0xB0000000 if VMSPLIT_3G_OPT
1060 default 0x80000000 if VMSPLIT_2G
1061 default 0x78000000 if VMSPLIT_2G_OPT
1062 default 0x40000000 if VMSPLIT_1G
1068 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1071 bool "PAE (Physical Address Extension) Support"
1072 depends on X86_32 && !HIGHMEM4G
1074 PAE is required for NX support, and furthermore enables
1075 larger swapspace support for non-overcommit purposes. It
1076 has the cost of more pagetable lookup overhead, and also
1077 consumes more pagetable space per process.
1079 config ARCH_PHYS_ADDR_T_64BIT
1080 def_bool X86_64 || X86_PAE
1082 config DIRECT_GBPAGES
1083 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1087 Allow the kernel linear mapping to use 1GB pages on CPUs that
1088 support it. This can improve the kernel's performance a tiny bit by
1089 reducing TLB pressure. If in doubt, say "Y".
1091 # Common NUMA Features
1093 bool "Numa Memory Allocation and Scheduler Support"
1095 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1096 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1098 Enable NUMA (Non Uniform Memory Access) support.
1100 The kernel will try to allocate memory used by a CPU on the
1101 local memory controller of the CPU and add some more
1102 NUMA awareness to the kernel.
1104 For 64-bit this is recommended if the system is Intel Core i7
1105 (or later), AMD Opteron, or EM64T NUMA.
1107 For 32-bit this is only needed on (rare) 32-bit-only platforms
1108 that support NUMA topologies, such as NUMAQ / Summit, or if you
1109 boot a 32-bit kernel on a 64-bit NUMA platform.
1111 Otherwise, you should say N.
1113 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1114 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1118 prompt "Old style AMD Opteron NUMA detection"
1119 depends on X86_64 && NUMA && PCI
1121 Enable K8 NUMA node topology detection. You should say Y here if
1122 you have a multi processor AMD K8 system. This uses an old
1123 method to read the NUMA configuration directly from the builtin
1124 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1125 instead, which also takes priority if both are compiled in.
1127 config X86_64_ACPI_NUMA
1129 prompt "ACPI NUMA detection"
1130 depends on X86_64 && NUMA && ACPI && PCI
1133 Enable ACPI SRAT based node topology detection.
1135 # Some NUMA nodes have memory ranges that span
1136 # other nodes. Even though a pfn is valid and
1137 # between a node's start and end pfns, it may not
1138 # reside on that node. See memmap_init_zone()
1140 config NODES_SPAN_OTHER_NODES
1142 depends on X86_64_ACPI_NUMA
1145 bool "NUMA emulation"
1146 depends on X86_64 && NUMA
1148 Enable NUMA emulation. A flat machine will be split
1149 into virtual nodes when booted with "numa=fake=N", where N is the
1150 number of nodes. This is only useful for debugging.
1153 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1155 default "9" if MAXSMP
1156 default "6" if X86_64
1157 default "4" if X86_NUMAQ
1159 depends on NEED_MULTIPLE_NODES
1161 Specify the maximum number of NUMA Nodes available on the target
1162 system. Increases memory reserved to accommodate various tables.
1164 config HAVE_ARCH_BOOTMEM
1166 depends on X86_32 && NUMA
1168 config ARCH_HAVE_MEMORY_PRESENT
1170 depends on X86_32 && DISCONTIGMEM
1172 config NEED_NODE_MEMMAP_SIZE
1174 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1176 config HAVE_ARCH_ALLOC_REMAP
1178 depends on X86_32 && NUMA
1180 config ARCH_FLATMEM_ENABLE
1182 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1184 config ARCH_DISCONTIGMEM_ENABLE
1186 depends on NUMA && X86_32
1188 config ARCH_DISCONTIGMEM_DEFAULT
1190 depends on NUMA && X86_32
1192 config ARCH_SPARSEMEM_DEFAULT
1196 config ARCH_SPARSEMEM_ENABLE
1198 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1199 select SPARSEMEM_STATIC if X86_32
1200 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1202 config ARCH_SELECT_MEMORY_MODEL
1204 depends on ARCH_SPARSEMEM_ENABLE
1206 config ARCH_MEMORY_PROBE
1208 depends on MEMORY_HOTPLUG
1213 bool "Allocate 3rd-level pagetables from highmem"
1214 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1216 The VM uses one page table entry for each page of physical memory.
1217 For systems with a lot of RAM, this can be wasteful of precious
1218 low memory. Setting this option will put user-space page table
1219 entries in high memory.
1221 config X86_CHECK_BIOS_CORRUPTION
1222 bool "Check for low memory corruption"
1224 Periodically check for memory corruption in low memory, which
1225 is suspected to be caused by BIOS. Even when enabled in the
1226 configuration, it is disabled at runtime. Enable it by
1227 setting "memory_corruption_check=1" on the kernel command
1228 line. By default it scans the low 64k of memory every 60
1229 seconds; see the memory_corruption_check_size and
1230 memory_corruption_check_period parameters in
1231 Documentation/kernel-parameters.txt to adjust this.
1233 When enabled with the default parameters, this option has
1234 almost no overhead, as it reserves a relatively small amount
1235 of memory and scans it infrequently. It both detects corruption
1236 and prevents it from affecting the running system.
1238 It is, however, intended as a diagnostic tool; if repeatable
1239 BIOS-originated corruption always affects the same memory,
1240 you can use memmap= to prevent the kernel from using that
1243 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1244 bool "Set the default setting of memory_corruption_check"
1245 depends on X86_CHECK_BIOS_CORRUPTION
1248 Set whether the default state of memory_corruption_check is
1251 config X86_RESERVE_LOW_64K
1252 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1255 Reserve the first 64K of physical RAM on BIOSes that are known
1256 to potentially corrupt that memory range. A numbers of BIOSes are
1257 known to utilize this area during suspend/resume, so it must not
1258 be used by the kernel.
1260 Set this to N if you are absolutely sure that you trust the BIOS
1261 to get all its memory reservations and usages right.
1263 If you have doubts about the BIOS (e.g. suspend/resume does not
1264 work or there's kernel crashes after certain hardware hotplug
1265 events) and it's not AMI or Phoenix, then you might want to enable
1266 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1267 corruption patterns.
1271 config MATH_EMULATION
1273 prompt "Math emulation" if X86_32
1275 Linux can emulate a math coprocessor (used for floating point
1276 operations) if you don't have one. 486DX and Pentium processors have
1277 a math coprocessor built in, 486SX and 386 do not, unless you added
1278 a 487DX or 387, respectively. (The messages during boot time can
1279 give you some hints here ["man dmesg"].) Everyone needs either a
1280 coprocessor or this emulation.
1282 If you don't have a math coprocessor, you need to say Y here; if you
1283 say Y here even though you have a coprocessor, the coprocessor will
1284 be used nevertheless. (This behavior can be changed with the kernel
1285 command line option "no387", which comes handy if your coprocessor
1286 is broken. Try "man bootparam" or see the documentation of your boot
1287 loader (lilo or loadlin) about how to pass options to the kernel at
1288 boot time.) This means that it is a good idea to say Y here if you
1289 intend to use this kernel on different machines.
1291 More information about the internals of the Linux math coprocessor
1292 emulation can be found in <file:arch/x86/math-emu/README>.
1294 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1295 kernel, it won't hurt.
1298 bool "MTRR (Memory Type Range Register) support"
1300 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1301 the Memory Type Range Registers (MTRRs) may be used to control
1302 processor access to memory ranges. This is most useful if you have
1303 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1304 allows bus write transfers to be combined into a larger transfer
1305 before bursting over the PCI/AGP bus. This can increase performance
1306 of image write operations 2.5 times or more. Saying Y here creates a
1307 /proc/mtrr file which may be used to manipulate your processor's
1308 MTRRs. Typically the X server should use this.
1310 This code has a reasonably generic interface so that similar
1311 control registers on other processors can be easily supported
1314 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1315 Registers (ARRs) which provide a similar functionality to MTRRs. For
1316 these, the ARRs are used to emulate the MTRRs.
1317 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1318 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1319 write-combining. All of these processors are supported by this code
1320 and it makes sense to say Y here if you have one of them.
1322 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1323 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1324 can lead to all sorts of problems, so it's good to say Y here.
1326 You can safely say Y even if your machine doesn't have MTRRs, you'll
1327 just add about 9 KB to your kernel.
1329 See <file:Documentation/x86/mtrr.txt> for more information.
1331 config MTRR_SANITIZER
1333 prompt "MTRR cleanup support"
1336 Convert MTRR layout from continuous to discrete, so X drivers can
1337 add writeback entries.
1339 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1340 The largest mtrr entry size for a continuous block can be set with
1345 config MTRR_SANITIZER_ENABLE_DEFAULT
1346 int "MTRR cleanup enable value (0-1)"
1349 depends on MTRR_SANITIZER
1351 Enable mtrr cleanup default value
1353 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1354 int "MTRR cleanup spare reg num (0-7)"
1357 depends on MTRR_SANITIZER
1359 mtrr cleanup spare entries default, it can be changed via
1360 mtrr_spare_reg_nr=N on the kernel command line.
1364 prompt "x86 PAT support"
1367 Use PAT attributes to setup page level cache control.
1369 PATs are the modern equivalents of MTRRs and are much more
1370 flexible than MTRRs.
1372 Say N here if you see bootup problems (boot crash, boot hang,
1373 spontaneous reboots) or a non-working video driver.
1378 bool "EFI runtime service support"
1381 This enables the kernel to use EFI runtime services that are
1382 available (such as the EFI variable services).
1384 This option is only useful on systems that have EFI firmware.
1385 In addition, you should use the latest ELILO loader available
1386 at <http://elilo.sourceforge.net> in order to take advantage
1387 of EFI runtime services. However, even with this option, the
1388 resultant kernel should continue to boot on existing non-EFI
1393 prompt "Enable seccomp to safely compute untrusted bytecode"
1395 This kernel feature is useful for number crunching applications
1396 that may need to compute untrusted bytecode during their
1397 execution. By using pipes or other transports made available to
1398 the process as file descriptors supporting the read/write
1399 syscalls, it's possible to isolate those applications in
1400 their own address space using seccomp. Once seccomp is
1401 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1402 and the task is only allowed to execute a few safe syscalls
1403 defined by each seccomp mode.
1405 If unsure, say Y. Only embedded should say N here.
1407 config CC_STACKPROTECTOR_ALL
1410 config CC_STACKPROTECTOR
1411 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1412 select CC_STACKPROTECTOR_ALL
1414 This option turns on the -fstack-protector GCC feature. This
1415 feature puts, at the beginning of functions, a canary value on
1416 the stack just before the return address, and validates
1417 the value just before actually returning. Stack based buffer
1418 overflows (that need to overwrite this return address) now also
1419 overwrite the canary, which gets detected and the attack is then
1420 neutralized via a kernel panic.
1422 This feature requires gcc version 4.2 or above, or a distribution
1423 gcc with the feature backported. Older versions are automatically
1424 detected and for those versions, this configuration option is
1425 ignored. (and a warning is printed during bootup)
1427 source kernel/Kconfig.hz
1430 bool "kexec system call"
1432 kexec is a system call that implements the ability to shutdown your
1433 current kernel, and to start another kernel. It is like a reboot
1434 but it is independent of the system firmware. And like a reboot
1435 you can start any kernel with it, not just Linux.
1437 The name comes from the similarity to the exec system call.
1439 It is an ongoing process to be certain the hardware in a machine
1440 is properly shutdown, so do not be surprised if this code does not
1441 initially work for you. It may help to enable device hotplugging
1442 support. As of this writing the exact hardware interface is
1443 strongly in flux, so no good recommendation can be made.
1446 bool "kernel crash dumps"
1447 depends on X86_64 || (X86_32 && HIGHMEM)
1449 Generate crash dump after being started by kexec.
1450 This should be normally only set in special crash dump kernels
1451 which are loaded in the main kernel with kexec-tools into
1452 a specially reserved region and then later executed after
1453 a crash by kdump/kexec. The crash dump kernel must be compiled
1454 to a memory address not used by the main kernel or BIOS using
1455 PHYSICAL_START, or it must be built as a relocatable image
1456 (CONFIG_RELOCATABLE=y).
1457 For more details see Documentation/kdump/kdump.txt
1460 bool "kexec jump (EXPERIMENTAL)"
1461 depends on EXPERIMENTAL
1462 depends on KEXEC && HIBERNATION
1464 Jump between original kernel and kexeced kernel and invoke
1465 code in physical address mode via KEXEC
1467 config PHYSICAL_START
1468 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1469 default "0x1000000" if X86_NUMAQ
1470 default "0x200000" if X86_64
1473 This gives the physical address where the kernel is loaded.
1475 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1476 bzImage will decompress itself to above physical address and
1477 run from there. Otherwise, bzImage will run from the address where
1478 it has been loaded by the boot loader and will ignore above physical
1481 In normal kdump cases one does not have to set/change this option
1482 as now bzImage can be compiled as a completely relocatable image
1483 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1484 address. This option is mainly useful for the folks who don't want
1485 to use a bzImage for capturing the crash dump and want to use a
1486 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1487 to be specifically compiled to run from a specific memory area
1488 (normally a reserved region) and this option comes handy.
1490 So if you are using bzImage for capturing the crash dump, leave
1491 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1492 Otherwise if you plan to use vmlinux for capturing the crash dump
1493 change this value to start of the reserved region (Typically 16MB
1494 0x1000000). In other words, it can be set based on the "X" value as
1495 specified in the "crashkernel=YM@XM" command line boot parameter
1496 passed to the panic-ed kernel. Typically this parameter is set as
1497 crashkernel=64M@16M. Please take a look at
1498 Documentation/kdump/kdump.txt for more details about crash dumps.
1500 Usage of bzImage for capturing the crash dump is recommended as
1501 one does not have to build two kernels. Same kernel can be used
1502 as production kernel and capture kernel. Above option should have
1503 gone away after relocatable bzImage support is introduced. But it
1504 is present because there are users out there who continue to use
1505 vmlinux for dump capture. This option should go away down the
1508 Don't change this unless you know what you are doing.
1511 bool "Build a relocatable kernel (EXPERIMENTAL)"
1512 depends on EXPERIMENTAL
1514 This builds a kernel image that retains relocation information
1515 so it can be loaded someplace besides the default 1MB.
1516 The relocations tend to make the kernel binary about 10% larger,
1517 but are discarded at runtime.
1519 One use is for the kexec on panic case where the recovery kernel
1520 must live at a different physical address than the primary
1523 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1524 it has been loaded at and the compile time physical address
1525 (CONFIG_PHYSICAL_START) is ignored.
1527 config PHYSICAL_ALIGN
1529 prompt "Alignment value to which kernel should be aligned" if X86_32
1530 default "0x100000" if X86_32
1531 default "0x200000" if X86_64
1532 range 0x2000 0x400000
1534 This value puts the alignment restrictions on physical address
1535 where kernel is loaded and run from. Kernel is compiled for an
1536 address which meets above alignment restriction.
1538 If bootloader loads the kernel at a non-aligned address and
1539 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1540 address aligned to above value and run from there.
1542 If bootloader loads the kernel at a non-aligned address and
1543 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1544 load address and decompress itself to the address it has been
1545 compiled for and run from there. The address for which kernel is
1546 compiled already meets above alignment restrictions. Hence the
1547 end result is that kernel runs from a physical address meeting
1548 above alignment restrictions.
1550 Don't change this unless you know what you are doing.
1553 bool "Support for hot-pluggable CPUs"
1554 depends on SMP && HOTPLUG
1556 Say Y here to allow turning CPUs off and on. CPUs can be
1557 controlled through /sys/devices/system/cpu.
1558 ( Note: power management support will enable this option
1559 automatically on SMP systems. )
1560 Say N if you want to disable CPU hotplug.
1564 prompt "Compat VDSO support"
1565 depends on X86_32 || IA32_EMULATION
1567 Map the 32-bit VDSO to the predictable old-style address too.
1569 Say N here if you are running a sufficiently recent glibc
1570 version (2.3.3 or later), to remove the high-mapped
1571 VDSO mapping and to exclusively use the randomized VDSO.
1576 bool "Built-in kernel command line"
1579 Allow for specifying boot arguments to the kernel at
1580 build time. On some systems (e.g. embedded ones), it is
1581 necessary or convenient to provide some or all of the
1582 kernel boot arguments with the kernel itself (that is,
1583 to not rely on the boot loader to provide them.)
1585 To compile command line arguments into the kernel,
1586 set this option to 'Y', then fill in the
1587 the boot arguments in CONFIG_CMDLINE.
1589 Systems with fully functional boot loaders (i.e. non-embedded)
1590 should leave this option set to 'N'.
1593 string "Built-in kernel command string"
1594 depends on CMDLINE_BOOL
1597 Enter arguments here that should be compiled into the kernel
1598 image and used at boot time. If the boot loader provides a
1599 command line at boot time, it is appended to this string to
1600 form the full kernel command line, when the system boots.
1602 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1603 change this behavior.
1605 In most cases, the command line (whether built-in or provided
1606 by the boot loader) should specify the device for the root
1609 config CMDLINE_OVERRIDE
1610 bool "Built-in command line overrides boot loader arguments"
1612 depends on CMDLINE_BOOL
1614 Set this option to 'Y' to have the kernel ignore the boot loader
1615 command line, and use ONLY the built-in command line.
1617 This is used to work around broken boot loaders. This should
1618 be set to 'N' under normal conditions.
1622 config ARCH_ENABLE_MEMORY_HOTPLUG
1624 depends on X86_64 || (X86_32 && HIGHMEM)
1626 config ARCH_ENABLE_MEMORY_HOTREMOVE
1628 depends on MEMORY_HOTPLUG
1630 config HAVE_ARCH_EARLY_PFN_TO_NID
1634 menu "Power management and ACPI options"
1636 config ARCH_HIBERNATION_HEADER
1638 depends on X86_64 && HIBERNATION
1640 source "kernel/power/Kconfig"
1642 source "drivers/acpi/Kconfig"
1647 depends on APM || APM_MODULE
1650 tristate "APM (Advanced Power Management) BIOS support"
1651 depends on X86_32 && PM_SLEEP
1653 APM is a BIOS specification for saving power using several different
1654 techniques. This is mostly useful for battery powered laptops with
1655 APM compliant BIOSes. If you say Y here, the system time will be
1656 reset after a RESUME operation, the /proc/apm device will provide
1657 battery status information, and user-space programs will receive
1658 notification of APM "events" (e.g. battery status change).
1660 If you select "Y" here, you can disable actual use of the APM
1661 BIOS by passing the "apm=off" option to the kernel at boot time.
1663 Note that the APM support is almost completely disabled for
1664 machines with more than one CPU.
1666 In order to use APM, you will need supporting software. For location
1667 and more information, read <file:Documentation/power/pm.txt> and the
1668 Battery Powered Linux mini-HOWTO, available from
1669 <http://www.tldp.org/docs.html#howto>.
1671 This driver does not spin down disk drives (see the hdparm(8)
1672 manpage ("man 8 hdparm") for that), and it doesn't turn off
1673 VESA-compliant "green" monitors.
1675 This driver does not support the TI 4000M TravelMate and the ACER
1676 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1677 desktop machines also don't have compliant BIOSes, and this driver
1678 may cause those machines to panic during the boot phase.
1680 Generally, if you don't have a battery in your machine, there isn't
1681 much point in using this driver and you should say N. If you get
1682 random kernel OOPSes or reboots that don't seem to be related to
1683 anything, try disabling/enabling this option (or disabling/enabling
1686 Some other things you should try when experiencing seemingly random,
1689 1) make sure that you have enough swap space and that it is
1691 2) pass the "no-hlt" option to the kernel
1692 3) switch on floating point emulation in the kernel and pass
1693 the "no387" option to the kernel
1694 4) pass the "floppy=nodma" option to the kernel
1695 5) pass the "mem=4M" option to the kernel (thereby disabling
1696 all but the first 4 MB of RAM)
1697 6) make sure that the CPU is not over clocked.
1698 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1699 8) disable the cache from your BIOS settings
1700 9) install a fan for the video card or exchange video RAM
1701 10) install a better fan for the CPU
1702 11) exchange RAM chips
1703 12) exchange the motherboard.
1705 To compile this driver as a module, choose M here: the
1706 module will be called apm.
1710 config APM_IGNORE_USER_SUSPEND
1711 bool "Ignore USER SUSPEND"
1713 This option will ignore USER SUSPEND requests. On machines with a
1714 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1715 series notebooks, it is necessary to say Y because of a BIOS bug.
1717 config APM_DO_ENABLE
1718 bool "Enable PM at boot time"
1720 Enable APM features at boot time. From page 36 of the APM BIOS
1721 specification: "When disabled, the APM BIOS does not automatically
1722 power manage devices, enter the Standby State, enter the Suspend
1723 State, or take power saving steps in response to CPU Idle calls."
1724 This driver will make CPU Idle calls when Linux is idle (unless this
1725 feature is turned off -- see "Do CPU IDLE calls", below). This
1726 should always save battery power, but more complicated APM features
1727 will be dependent on your BIOS implementation. You may need to turn
1728 this option off if your computer hangs at boot time when using APM
1729 support, or if it beeps continuously instead of suspending. Turn
1730 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1731 T400CDT. This is off by default since most machines do fine without
1735 bool "Make CPU Idle calls when idle"
1737 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1738 On some machines, this can activate improved power savings, such as
1739 a slowed CPU clock rate, when the machine is idle. These idle calls
1740 are made after the idle loop has run for some length of time (e.g.,
1741 333 mS). On some machines, this will cause a hang at boot time or
1742 whenever the CPU becomes idle. (On machines with more than one CPU,
1743 this option does nothing.)
1745 config APM_DISPLAY_BLANK
1746 bool "Enable console blanking using APM"
1748 Enable console blanking using the APM. Some laptops can use this to
1749 turn off the LCD backlight when the screen blanker of the Linux
1750 virtual console blanks the screen. Note that this is only used by
1751 the virtual console screen blanker, and won't turn off the backlight
1752 when using the X Window system. This also doesn't have anything to
1753 do with your VESA-compliant power-saving monitor. Further, this
1754 option doesn't work for all laptops -- it might not turn off your
1755 backlight at all, or it might print a lot of errors to the console,
1756 especially if you are using gpm.
1758 config APM_ALLOW_INTS
1759 bool "Allow interrupts during APM BIOS calls"
1761 Normally we disable external interrupts while we are making calls to
1762 the APM BIOS as a measure to lessen the effects of a badly behaving
1763 BIOS implementation. The BIOS should reenable interrupts if it
1764 needs to. Unfortunately, some BIOSes do not -- especially those in
1765 many of the newer IBM Thinkpads. If you experience hangs when you
1766 suspend, try setting this to Y. Otherwise, say N.
1770 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1772 source "drivers/cpuidle/Kconfig"
1774 source "drivers/idle/Kconfig"
1779 menu "Bus options (PCI etc.)"
1784 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1786 Find out whether you have a PCI motherboard. PCI is the name of a
1787 bus system, i.e. the way the CPU talks to the other stuff inside
1788 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1789 VESA. If you have PCI, say Y, otherwise N.
1792 prompt "PCI access mode"
1793 depends on X86_32 && PCI
1796 On PCI systems, the BIOS can be used to detect the PCI devices and
1797 determine their configuration. However, some old PCI motherboards
1798 have BIOS bugs and may crash if this is done. Also, some embedded
1799 PCI-based systems don't have any BIOS at all. Linux can also try to
1800 detect the PCI hardware directly without using the BIOS.
1802 With this option, you can specify how Linux should detect the
1803 PCI devices. If you choose "BIOS", the BIOS will be used,
1804 if you choose "Direct", the BIOS won't be used, and if you
1805 choose "MMConfig", then PCI Express MMCONFIG will be used.
1806 If you choose "Any", the kernel will try MMCONFIG, then the
1807 direct access method and falls back to the BIOS if that doesn't
1808 work. If unsure, go with the default, which is "Any".
1813 config PCI_GOMMCONFIG
1830 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1832 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1835 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1839 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1843 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1850 bool "Support mmconfig PCI config space access"
1851 depends on X86_64 && PCI && ACPI
1854 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1855 depends on PCI_MSI && ACPI && EXPERIMENTAL
1857 DMA remapping (DMAR) devices support enables independent address
1858 translations for Direct Memory Access (DMA) from devices.
1859 These DMA remapping devices are reported via ACPI tables
1860 and include PCI device scope covered by these DMA
1863 config DMAR_DEFAULT_ON
1865 prompt "Enable DMA Remapping Devices by default"
1868 Selecting this option will enable a DMAR device at boot time if
1869 one is found. If this option is not selected, DMAR support can
1870 be enabled by passing intel_iommu=on to the kernel. It is
1871 recommended you say N here while the DMAR code remains
1876 prompt "Support for Graphics workaround"
1879 Current Graphics drivers tend to use physical address
1880 for DMA and avoid using DMA APIs. Setting this config
1881 option permits the IOMMU driver to set a unity map for
1882 all the OS-visible memory. Hence the driver can continue
1883 to use physical addresses for DMA.
1885 config DMAR_FLOPPY_WA
1889 Floppy disk drivers are know to bypass DMA API calls
1890 thereby failing to work when IOMMU is enabled. This
1891 workaround will setup a 1:1 mapping for the first
1892 16M to make floppy (an ISA device) work.
1895 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1896 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1898 Supports Interrupt remapping for IO-APIC and MSI devices.
1899 To use x2apic mode in the CPU's which support x2APIC enhancements or
1900 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1902 source "drivers/pci/pcie/Kconfig"
1904 source "drivers/pci/Kconfig"
1906 # x86_64 have no ISA slots, but do have ISA-style DMA.
1915 Find out whether you have ISA slots on your motherboard. ISA is the
1916 name of a bus system, i.e. the way the CPU talks to the other stuff
1917 inside your box. Other bus systems are PCI, EISA, MicroChannel
1918 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1919 newer boards don't support it. If you have ISA, say Y, otherwise N.
1925 The Extended Industry Standard Architecture (EISA) bus was
1926 developed as an open alternative to the IBM MicroChannel bus.
1928 The EISA bus provided some of the features of the IBM MicroChannel
1929 bus while maintaining backward compatibility with cards made for
1930 the older ISA bus. The EISA bus saw limited use between 1988 and
1931 1995 when it was made obsolete by the PCI bus.
1933 Say Y here if you are building a kernel for an EISA-based machine.
1937 source "drivers/eisa/Kconfig"
1942 MicroChannel Architecture is found in some IBM PS/2 machines and
1943 laptops. It is a bus system similar to PCI or ISA. See
1944 <file:Documentation/mca.txt> (and especially the web page given
1945 there) before attempting to build an MCA bus kernel.
1947 source "drivers/mca/Kconfig"
1950 tristate "NatSemi SCx200 support"
1952 This provides basic support for National Semiconductor's
1953 (now AMD's) Geode processors. The driver probes for the
1954 PCI-IDs of several on-chip devices, so its a good dependency
1955 for other scx200_* drivers.
1957 If compiled as a module, the driver is named scx200.
1959 config SCx200HR_TIMER
1960 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1961 depends on SCx200 && GENERIC_TIME
1964 This driver provides a clocksource built upon the on-chip
1965 27MHz high-resolution timer. Its also a workaround for
1966 NSC Geode SC-1100's buggy TSC, which loses time when the
1967 processor goes idle (as is done by the scheduler). The
1968 other workaround is idle=poll boot option.
1970 config GEODE_MFGPT_TIMER
1972 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1973 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1975 This driver provides a clock event source based on the MFGPT
1976 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1977 MFGPTs have a better resolution and max interval than the
1978 generic PIT, and are suitable for use as high-res timers.
1981 bool "One Laptop Per Child support"
1984 Add support for detecting the unique features of the OLPC
1991 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1993 source "drivers/pcmcia/Kconfig"
1995 source "drivers/pci/hotplug/Kconfig"
2000 menu "Executable file formats / Emulations"
2002 source "fs/Kconfig.binfmt"
2004 config IA32_EMULATION
2005 bool "IA32 Emulation"
2007 select COMPAT_BINFMT_ELF
2009 Include code to run 32-bit programs under a 64-bit kernel. You should
2010 likely turn this on, unless you're 100% sure that you don't have any
2011 32-bit programs left.
2014 tristate "IA32 a.out support"
2015 depends on IA32_EMULATION
2017 Support old a.out binaries in the 32bit emulation.
2021 depends on IA32_EMULATION
2023 config COMPAT_FOR_U64_ALIGNMENT
2027 config SYSVIPC_COMPAT
2029 depends on COMPAT && SYSVIPC
2034 config HAVE_ATOMIC_IOMAP
2038 source "net/Kconfig"
2040 source "drivers/Kconfig"
2042 source "drivers/firmware/Kconfig"
2046 source "arch/x86/Kconfig.debug"
2048 source "security/Kconfig"
2050 source "crypto/Kconfig"
2052 source "arch/x86/kvm/Kconfig"
2054 source "lib/Kconfig"
projects / linux-2.6 / blob