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
49 select HAVE_ARCH_KMEMCHECK
53 default "elf32-i386" if X86_32
54 default "elf64-x86-64" if X86_64
58 default "arch/x86/configs/i386_defconfig" if X86_32
59 default "arch/x86/configs/x86_64_defconfig" if X86_64
64 config GENERIC_CMOS_UPDATE
67 config CLOCKSOURCE_WATCHDOG
70 config GENERIC_CLOCKEVENTS
73 config GENERIC_CLOCKEVENTS_BROADCAST
75 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
77 config LOCKDEP_SUPPORT
80 config STACKTRACE_SUPPORT
83 config HAVE_LATENCYTOP_SUPPORT
86 config FAST_CMPXCHG_LOCAL
99 config GENERIC_ISA_DMA
108 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
110 config GENERIC_BUG_RELATIVE_POINTERS
113 config GENERIC_HWEIGHT
119 config ARCH_MAY_HAVE_PC_FDC
122 config RWSEM_GENERIC_SPINLOCK
125 config RWSEM_XCHGADD_ALGORITHM
128 config ARCH_HAS_CPU_IDLE_WAIT
131 config GENERIC_CALIBRATE_DELAY
134 config GENERIC_TIME_VSYSCALL
138 config ARCH_HAS_CPU_RELAX
141 config ARCH_HAS_DEFAULT_IDLE
144 config ARCH_HAS_CACHE_LINE_SIZE
147 config HAVE_SETUP_PER_CPU_AREA
150 config HAVE_DYNAMIC_PER_CPU_AREA
153 config HAVE_CPUMASK_OF_CPU_MAP
156 config ARCH_HIBERNATION_POSSIBLE
159 config ARCH_SUSPEND_POSSIBLE
166 config ARCH_POPULATES_NODE_MAP
173 config ARCH_SUPPORTS_OPTIMIZED_INLINING
176 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
179 # Use the generic interrupt handling code in kernel/irq/:
180 config GENERIC_HARDIRQS
184 config GENERIC_HARDIRQS_NO__DO_IRQ
187 config GENERIC_IRQ_PROBE
191 config GENERIC_PENDING_IRQ
193 depends on GENERIC_HARDIRQS && SMP
196 config USE_GENERIC_SMP_HELPERS
202 depends on X86_32 && SMP
206 depends on X86_64 && SMP
213 config X86_TRAMPOLINE
215 depends on SMP || (64BIT && ACPI_SLEEP)
218 config X86_32_LAZY_GS
220 depends on X86_32 && !CC_STACKPROTECTOR
224 source "init/Kconfig"
225 source "kernel/Kconfig.freezer"
227 menu "Processor type and features"
229 source "kernel/time/Kconfig"
232 bool "Symmetric multi-processing support"
234 This enables support for systems with more than one CPU. If you have
235 a system with only one CPU, like most personal computers, say N. If
236 you have a system with more than one CPU, say Y.
238 If you say N here, the kernel will run on single and multiprocessor
239 machines, but will use only one CPU of a multiprocessor machine. If
240 you say Y here, the kernel will run on many, but not all,
241 singleprocessor machines. On a singleprocessor machine, the kernel
242 will run faster if you say N here.
244 Note that if you say Y here and choose architecture "586" or
245 "Pentium" under "Processor family", the kernel will not work on 486
246 architectures. Similarly, multiprocessor kernels for the "PPro"
247 architecture may not work on all Pentium based boards.
249 People using multiprocessor machines who say Y here should also say
250 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
251 Management" code will be disabled if you say Y here.
253 See also <file:Documentation/i386/IO-APIC.txt>,
254 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
255 <http://www.tldp.org/docs.html#howto>.
257 If you don't know what to do here, say N.
260 bool "Support x2apic"
261 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
263 This enables x2apic support on CPUs that have this feature.
265 This allows 32-bit apic IDs (so it can support very large systems),
266 and accesses the local apic via MSRs not via mmio.
268 If you don't know what to do here, say N.
271 bool "Support sparse irq numbering"
272 depends on PCI_MSI || HT_IRQ
274 This enables support for sparse irqs. This is useful for distro
275 kernels that want to define a high CONFIG_NR_CPUS value but still
276 want to have low kernel memory footprint on smaller machines.
278 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
279 out the irq_desc[] array in a more NUMA-friendly way. )
281 If you don't know what to do here, say N.
285 depends on SPARSE_IRQ && NUMA
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
358 depends on X86_X2APIC
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
743 select HAVE_PERF_COUNTERS if (!M386 && !M486)
747 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
749 config X86_VISWS_APIC
751 depends on X86_32 && X86_VISWS
753 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
754 bool "Reroute for broken boot IRQs"
756 depends on X86_IO_APIC
758 This option enables a workaround that fixes a source of
759 spurious interrupts. This is recommended when threaded
760 interrupt handling is used on systems where the generation of
761 superfluous "boot interrupts" cannot be disabled.
763 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
764 entry in the chipset's IO-APIC is masked (as, e.g. the RT
765 kernel does during interrupt handling). On chipsets where this
766 boot IRQ generation cannot be disabled, this workaround keeps
767 the original IRQ line masked so that only the equivalent "boot
768 IRQ" is delivered to the CPUs. The workaround also tells the
769 kernel to set up the IRQ handler on the boot IRQ line. In this
770 way only one interrupt is delivered to the kernel. Otherwise
771 the spurious second interrupt may cause the kernel to bring
772 down (vital) interrupt lines.
774 Only affects "broken" chipsets. Interrupt sharing may be
775 increased on these systems.
778 bool "Machine Check Exception"
780 Machine Check Exception support allows the processor to notify the
781 kernel if it detects a problem (e.g. overheating, component failure).
782 The action the kernel takes depends on the severity of the problem,
783 ranging from a warning message on the console, to halting the machine.
784 Your processor must be a Pentium or newer to support this - check the
785 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
786 have a design flaw which leads to false MCE events - hence MCE is
787 disabled on all P5 processors, unless explicitly enabled with "mce"
788 as a boot argument. Similarly, if MCE is built in and creates a
789 problem on some new non-standard machine, you can boot with "nomce"
790 to disable it. MCE support simply ignores non-MCE processors like
791 the 386 and 486, so nearly everyone can say Y here.
795 prompt "Intel MCE features"
796 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
798 Additional support for intel specific MCE features such as
803 prompt "AMD MCE features"
804 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
806 Additional support for AMD specific MCE features such as
807 the DRAM Error Threshold.
809 config X86_MCE_THRESHOLD
810 depends on X86_MCE_AMD || X86_MCE_INTEL
814 config X86_MCE_NONFATAL
815 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
816 depends on X86_32 && X86_MCE
818 Enabling this feature starts a timer that triggers every 5 seconds which
819 will look at the machine check registers to see if anything happened.
820 Non-fatal problems automatically get corrected (but still logged).
821 Disable this if you don't want to see these messages.
822 Seeing the messages this option prints out may be indicative of dying
823 or out-of-spec (ie, overclocked) hardware.
824 This option only does something on certain CPUs.
825 (AMD Athlon/Duron and Intel Pentium 4)
827 config X86_MCE_P4THERMAL
828 bool "check for P4 thermal throttling interrupt."
829 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
831 Enabling this feature will cause a message to be printed when the P4
832 enters thermal throttling.
835 bool "Enable VM86 support" if EMBEDDED
839 This option is required by programs like DOSEMU to run 16-bit legacy
840 code on X86 processors. It also may be needed by software like
841 XFree86 to initialize some video cards via BIOS. Disabling this
842 option saves about 6k.
845 tristate "Toshiba Laptop support"
848 This adds a driver to safely access the System Management Mode of
849 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
850 not work on models with a Phoenix BIOS. The System Management Mode
851 is used to set the BIOS and power saving options on Toshiba portables.
853 For information on utilities to make use of this driver see the
854 Toshiba Linux utilities web site at:
855 <http://www.buzzard.org.uk/toshiba/>.
857 Say Y if you intend to run this kernel on a Toshiba portable.
861 tristate "Dell laptop support"
863 This adds a driver to safely access the System Management Mode
864 of the CPU on the Dell Inspiron 8000. The System Management Mode
865 is used to read cpu temperature and cooling fan status and to
866 control the fans on the I8K portables.
868 This driver has been tested only on the Inspiron 8000 but it may
869 also work with other Dell laptops. You can force loading on other
870 models by passing the parameter `force=1' to the module. Use at
873 For information on utilities to make use of this driver see the
874 I8K Linux utilities web site at:
875 <http://people.debian.org/~dz/i8k/>
877 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
880 config X86_REBOOTFIXUPS
881 bool "Enable X86 board specific fixups for reboot"
884 This enables chipset and/or board specific fixups to be done
885 in order to get reboot to work correctly. This is only needed on
886 some combinations of hardware and BIOS. The symptom, for which
887 this config is intended, is when reboot ends with a stalled/hung
890 Currently, the only fixup is for the Geode machines using
891 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
893 Say Y if you want to enable the fixup. Currently, it's safe to
894 enable this option even if you don't need it.
898 tristate "/dev/cpu/microcode - microcode support"
901 If you say Y here, you will be able to update the microcode on
902 certain Intel and AMD processors. The Intel support is for the
903 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
904 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
905 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
906 You will obviously need the actual microcode binary data itself
907 which is not shipped with the Linux kernel.
909 This option selects the general module only, you need to select
910 at least one vendor specific module as well.
912 To compile this driver as a module, choose M here: the
913 module will be called microcode.
915 config MICROCODE_INTEL
916 bool "Intel microcode patch loading support"
921 This options enables microcode patch loading support for Intel
924 For latest news and information on obtaining all the required
925 Intel ingredients for this driver, check:
926 <http://www.urbanmyth.org/microcode/>.
929 bool "AMD microcode patch loading support"
933 If you select this option, microcode patch loading support for AMD
934 processors will be enabled.
936 config MICROCODE_OLD_INTERFACE
941 tristate "/dev/cpu/*/msr - Model-specific register support"
943 This device gives privileged processes access to the x86
944 Model-Specific Registers (MSRs). It is a character device with
945 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
946 MSR accesses are directed to a specific CPU on multi-processor
950 tristate "/dev/cpu/*/cpuid - CPU information support"
952 This device gives processes access to the x86 CPUID instruction to
953 be executed on a specific processor. It is a character device
954 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
958 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
960 If you select this option, this will provide various x86 CPUs
961 information through debugfs.
964 prompt "High Memory Support"
965 default HIGHMEM4G if !X86_NUMAQ
966 default HIGHMEM64G if X86_NUMAQ
971 depends on !X86_NUMAQ
973 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
974 However, the address space of 32-bit x86 processors is only 4
975 Gigabytes large. That means that, if you have a large amount of
976 physical memory, not all of it can be "permanently mapped" by the
977 kernel. The physical memory that's not permanently mapped is called
980 If you are compiling a kernel which will never run on a machine with
981 more than 1 Gigabyte total physical RAM, answer "off" here (default
982 choice and suitable for most users). This will result in a "3GB/1GB"
983 split: 3GB are mapped so that each process sees a 3GB virtual memory
984 space and the remaining part of the 4GB virtual memory space is used
985 by the kernel to permanently map as much physical memory as
988 If the machine has between 1 and 4 Gigabytes physical RAM, then
991 If more than 4 Gigabytes is used then answer "64GB" here. This
992 selection turns Intel PAE (Physical Address Extension) mode on.
993 PAE implements 3-level paging on IA32 processors. PAE is fully
994 supported by Linux, PAE mode is implemented on all recent Intel
995 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
996 then the kernel will not boot on CPUs that don't support PAE!
998 The actual amount of total physical memory will either be
999 auto detected or can be forced by using a kernel command line option
1000 such as "mem=256M". (Try "man bootparam" or see the documentation of
1001 your boot loader (lilo or loadlin) about how to pass options to the
1002 kernel at boot time.)
1004 If unsure, say "off".
1008 depends on !X86_NUMAQ
1010 Select this if you have a 32-bit processor and between 1 and 4
1011 gigabytes of physical RAM.
1015 depends on !M386 && !M486
1018 Select this if you have a 32-bit processor and more than 4
1019 gigabytes of physical RAM.
1024 depends on EXPERIMENTAL
1025 prompt "Memory split" if EMBEDDED
1029 Select the desired split between kernel and user memory.
1031 If the address range available to the kernel is less than the
1032 physical memory installed, the remaining memory will be available
1033 as "high memory". Accessing high memory is a little more costly
1034 than low memory, as it needs to be mapped into the kernel first.
1035 Note that increasing the kernel address space limits the range
1036 available to user programs, making the address space there
1037 tighter. Selecting anything other than the default 3G/1G split
1038 will also likely make your kernel incompatible with binary-only
1041 If you are not absolutely sure what you are doing, leave this
1045 bool "3G/1G user/kernel split"
1046 config VMSPLIT_3G_OPT
1048 bool "3G/1G user/kernel split (for full 1G low memory)"
1050 bool "2G/2G user/kernel split"
1051 config VMSPLIT_2G_OPT
1053 bool "2G/2G user/kernel split (for full 2G low memory)"
1055 bool "1G/3G user/kernel split"
1060 default 0xB0000000 if VMSPLIT_3G_OPT
1061 default 0x80000000 if VMSPLIT_2G
1062 default 0x78000000 if VMSPLIT_2G_OPT
1063 default 0x40000000 if VMSPLIT_1G
1069 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1072 bool "PAE (Physical Address Extension) Support"
1073 depends on X86_32 && !HIGHMEM4G
1075 PAE is required for NX support, and furthermore enables
1076 larger swapspace support for non-overcommit purposes. It
1077 has the cost of more pagetable lookup overhead, and also
1078 consumes more pagetable space per process.
1080 config ARCH_PHYS_ADDR_T_64BIT
1081 def_bool X86_64 || X86_PAE
1083 config DIRECT_GBPAGES
1084 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1088 Allow the kernel linear mapping to use 1GB pages on CPUs that
1089 support it. This can improve the kernel's performance a tiny bit by
1090 reducing TLB pressure. If in doubt, say "Y".
1092 # Common NUMA Features
1094 bool "Numa Memory Allocation and Scheduler Support"
1096 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1097 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1099 Enable NUMA (Non Uniform Memory Access) support.
1101 The kernel will try to allocate memory used by a CPU on the
1102 local memory controller of the CPU and add some more
1103 NUMA awareness to the kernel.
1105 For 64-bit this is recommended if the system is Intel Core i7
1106 (or later), AMD Opteron, or EM64T NUMA.
1108 For 32-bit this is only needed on (rare) 32-bit-only platforms
1109 that support NUMA topologies, such as NUMAQ / Summit, or if you
1110 boot a 32-bit kernel on a 64-bit NUMA platform.
1112 Otherwise, you should say N.
1114 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1115 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1119 prompt "Old style AMD Opteron NUMA detection"
1120 depends on X86_64 && NUMA && PCI
1122 Enable K8 NUMA node topology detection. You should say Y here if
1123 you have a multi processor AMD K8 system. This uses an old
1124 method to read the NUMA configuration directly from the builtin
1125 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1126 instead, which also takes priority if both are compiled in.
1128 config X86_64_ACPI_NUMA
1130 prompt "ACPI NUMA detection"
1131 depends on X86_64 && NUMA && ACPI && PCI
1134 Enable ACPI SRAT based node topology detection.
1136 # Some NUMA nodes have memory ranges that span
1137 # other nodes. Even though a pfn is valid and
1138 # between a node's start and end pfns, it may not
1139 # reside on that node. See memmap_init_zone()
1141 config NODES_SPAN_OTHER_NODES
1143 depends on X86_64_ACPI_NUMA
1146 bool "NUMA emulation"
1147 depends on X86_64 && NUMA
1149 Enable NUMA emulation. A flat machine will be split
1150 into virtual nodes when booted with "numa=fake=N", where N is the
1151 number of nodes. This is only useful for debugging.
1154 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1156 default "9" if MAXSMP
1157 default "6" if X86_64
1158 default "4" if X86_NUMAQ
1160 depends on NEED_MULTIPLE_NODES
1162 Specify the maximum number of NUMA Nodes available on the target
1163 system. Increases memory reserved to accommodate various tables.
1165 config HAVE_ARCH_BOOTMEM
1167 depends on X86_32 && NUMA
1169 config ARCH_HAVE_MEMORY_PRESENT
1171 depends on X86_32 && DISCONTIGMEM
1173 config NEED_NODE_MEMMAP_SIZE
1175 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1177 config HAVE_ARCH_ALLOC_REMAP
1179 depends on X86_32 && NUMA
1181 config ARCH_FLATMEM_ENABLE
1183 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1185 config ARCH_DISCONTIGMEM_ENABLE
1187 depends on NUMA && X86_32
1189 config ARCH_DISCONTIGMEM_DEFAULT
1191 depends on NUMA && X86_32
1193 config ARCH_SPARSEMEM_DEFAULT
1197 config ARCH_SPARSEMEM_ENABLE
1199 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1200 select SPARSEMEM_STATIC if X86_32
1201 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1203 config ARCH_SELECT_MEMORY_MODEL
1205 depends on ARCH_SPARSEMEM_ENABLE
1207 config ARCH_MEMORY_PROBE
1209 depends on MEMORY_HOTPLUG
1214 bool "Allocate 3rd-level pagetables from highmem"
1215 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1217 The VM uses one page table entry for each page of physical memory.
1218 For systems with a lot of RAM, this can be wasteful of precious
1219 low memory. Setting this option will put user-space page table
1220 entries in high memory.
1222 config X86_CHECK_BIOS_CORRUPTION
1223 bool "Check for low memory corruption"
1225 Periodically check for memory corruption in low memory, which
1226 is suspected to be caused by BIOS. Even when enabled in the
1227 configuration, it is disabled at runtime. Enable it by
1228 setting "memory_corruption_check=1" on the kernel command
1229 line. By default it scans the low 64k of memory every 60
1230 seconds; see the memory_corruption_check_size and
1231 memory_corruption_check_period parameters in
1232 Documentation/kernel-parameters.txt to adjust this.
1234 When enabled with the default parameters, this option has
1235 almost no overhead, as it reserves a relatively small amount
1236 of memory and scans it infrequently. It both detects corruption
1237 and prevents it from affecting the running system.
1239 It is, however, intended as a diagnostic tool; if repeatable
1240 BIOS-originated corruption always affects the same memory,
1241 you can use memmap= to prevent the kernel from using that
1244 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1245 bool "Set the default setting of memory_corruption_check"
1246 depends on X86_CHECK_BIOS_CORRUPTION
1249 Set whether the default state of memory_corruption_check is
1252 config X86_RESERVE_LOW_64K
1253 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1256 Reserve the first 64K of physical RAM on BIOSes that are known
1257 to potentially corrupt that memory range. A numbers of BIOSes are
1258 known to utilize this area during suspend/resume, so it must not
1259 be used by the kernel.
1261 Set this to N if you are absolutely sure that you trust the BIOS
1262 to get all its memory reservations and usages right.
1264 If you have doubts about the BIOS (e.g. suspend/resume does not
1265 work or there's kernel crashes after certain hardware hotplug
1266 events) and it's not AMI or Phoenix, then you might want to enable
1267 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1268 corruption patterns.
1272 config MATH_EMULATION
1274 prompt "Math emulation" if X86_32
1276 Linux can emulate a math coprocessor (used for floating point
1277 operations) if you don't have one. 486DX and Pentium processors have
1278 a math coprocessor built in, 486SX and 386 do not, unless you added
1279 a 487DX or 387, respectively. (The messages during boot time can
1280 give you some hints here ["man dmesg"].) Everyone needs either a
1281 coprocessor or this emulation.
1283 If you don't have a math coprocessor, you need to say Y here; if you
1284 say Y here even though you have a coprocessor, the coprocessor will
1285 be used nevertheless. (This behavior can be changed with the kernel
1286 command line option "no387", which comes handy if your coprocessor
1287 is broken. Try "man bootparam" or see the documentation of your boot
1288 loader (lilo or loadlin) about how to pass options to the kernel at
1289 boot time.) This means that it is a good idea to say Y here if you
1290 intend to use this kernel on different machines.
1292 More information about the internals of the Linux math coprocessor
1293 emulation can be found in <file:arch/x86/math-emu/README>.
1295 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1296 kernel, it won't hurt.
1299 bool "MTRR (Memory Type Range Register) support"
1301 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1302 the Memory Type Range Registers (MTRRs) may be used to control
1303 processor access to memory ranges. This is most useful if you have
1304 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1305 allows bus write transfers to be combined into a larger transfer
1306 before bursting over the PCI/AGP bus. This can increase performance
1307 of image write operations 2.5 times or more. Saying Y here creates a
1308 /proc/mtrr file which may be used to manipulate your processor's
1309 MTRRs. Typically the X server should use this.
1311 This code has a reasonably generic interface so that similar
1312 control registers on other processors can be easily supported
1315 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1316 Registers (ARRs) which provide a similar functionality to MTRRs. For
1317 these, the ARRs are used to emulate the MTRRs.
1318 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1319 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1320 write-combining. All of these processors are supported by this code
1321 and it makes sense to say Y here if you have one of them.
1323 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1324 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1325 can lead to all sorts of problems, so it's good to say Y here.
1327 You can safely say Y even if your machine doesn't have MTRRs, you'll
1328 just add about 9 KB to your kernel.
1330 See <file:Documentation/x86/mtrr.txt> for more information.
1332 config MTRR_SANITIZER
1334 prompt "MTRR cleanup support"
1337 Convert MTRR layout from continuous to discrete, so X drivers can
1338 add writeback entries.
1340 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1341 The largest mtrr entry size for a continuous block can be set with
1346 config MTRR_SANITIZER_ENABLE_DEFAULT
1347 int "MTRR cleanup enable value (0-1)"
1350 depends on MTRR_SANITIZER
1352 Enable mtrr cleanup default value
1354 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1355 int "MTRR cleanup spare reg num (0-7)"
1358 depends on MTRR_SANITIZER
1360 mtrr cleanup spare entries default, it can be changed via
1361 mtrr_spare_reg_nr=N on the kernel command line.
1365 prompt "x86 PAT support"
1368 Use PAT attributes to setup page level cache control.
1370 PATs are the modern equivalents of MTRRs and are much more
1371 flexible than MTRRs.
1373 Say N here if you see bootup problems (boot crash, boot hang,
1374 spontaneous reboots) or a non-working video driver.
1379 bool "EFI runtime service support"
1382 This enables the kernel to use EFI runtime services that are
1383 available (such as the EFI variable services).
1385 This option is only useful on systems that have EFI firmware.
1386 In addition, you should use the latest ELILO loader available
1387 at <http://elilo.sourceforge.net> in order to take advantage
1388 of EFI runtime services. However, even with this option, the
1389 resultant kernel should continue to boot on existing non-EFI
1394 prompt "Enable seccomp to safely compute untrusted bytecode"
1396 This kernel feature is useful for number crunching applications
1397 that may need to compute untrusted bytecode during their
1398 execution. By using pipes or other transports made available to
1399 the process as file descriptors supporting the read/write
1400 syscalls, it's possible to isolate those applications in
1401 their own address space using seccomp. Once seccomp is
1402 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1403 and the task is only allowed to execute a few safe syscalls
1404 defined by each seccomp mode.
1406 If unsure, say Y. Only embedded should say N here.
1408 config CC_STACKPROTECTOR_ALL
1411 config CC_STACKPROTECTOR
1412 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1413 select CC_STACKPROTECTOR_ALL
1415 This option turns on the -fstack-protector GCC feature. This
1416 feature puts, at the beginning of functions, a canary value on
1417 the stack just before the return address, and validates
1418 the value just before actually returning. Stack based buffer
1419 overflows (that need to overwrite this return address) now also
1420 overwrite the canary, which gets detected and the attack is then
1421 neutralized via a kernel panic.
1423 This feature requires gcc version 4.2 or above, or a distribution
1424 gcc with the feature backported. Older versions are automatically
1425 detected and for those versions, this configuration option is
1426 ignored. (and a warning is printed during bootup)
1428 source kernel/Kconfig.hz
1431 bool "kexec system call"
1433 kexec is a system call that implements the ability to shutdown your
1434 current kernel, and to start another kernel. It is like a reboot
1435 but it is independent of the system firmware. And like a reboot
1436 you can start any kernel with it, not just Linux.
1438 The name comes from the similarity to the exec system call.
1440 It is an ongoing process to be certain the hardware in a machine
1441 is properly shutdown, so do not be surprised if this code does not
1442 initially work for you. It may help to enable device hotplugging
1443 support. As of this writing the exact hardware interface is
1444 strongly in flux, so no good recommendation can be made.
1447 bool "kernel crash dumps"
1448 depends on X86_64 || (X86_32 && HIGHMEM)
1450 Generate crash dump after being started by kexec.
1451 This should be normally only set in special crash dump kernels
1452 which are loaded in the main kernel with kexec-tools into
1453 a specially reserved region and then later executed after
1454 a crash by kdump/kexec. The crash dump kernel must be compiled
1455 to a memory address not used by the main kernel or BIOS using
1456 PHYSICAL_START, or it must be built as a relocatable image
1457 (CONFIG_RELOCATABLE=y).
1458 For more details see Documentation/kdump/kdump.txt
1461 bool "kexec jump (EXPERIMENTAL)"
1462 depends on EXPERIMENTAL
1463 depends on KEXEC && HIBERNATION
1465 Jump between original kernel and kexeced kernel and invoke
1466 code in physical address mode via KEXEC
1468 config PHYSICAL_START
1469 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1472 This gives the physical address where the kernel is loaded.
1474 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1475 bzImage will decompress itself to above physical address and
1476 run from there. Otherwise, bzImage will run from the address where
1477 it has been loaded by the boot loader and will ignore above physical
1480 In normal kdump cases one does not have to set/change this option
1481 as now bzImage can be compiled as a completely relocatable image
1482 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1483 address. This option is mainly useful for the folks who don't want
1484 to use a bzImage for capturing the crash dump and want to use a
1485 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1486 to be specifically compiled to run from a specific memory area
1487 (normally a reserved region) and this option comes handy.
1489 So if you are using bzImage for capturing the crash dump,
1490 leave the value here unchanged to 0x1000000 and set
1491 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1492 for capturing the crash dump change this value to start of
1493 the reserved region. In other words, it can be set based on
1494 the "X" value as specified in the "crashkernel=YM@XM"
1495 command line boot parameter passed to the panic-ed
1496 kernel. Please take a look at Documentation/kdump/kdump.txt
1497 for more details about crash dumps.
1499 Usage of bzImage for capturing the crash dump is recommended as
1500 one does not have to build two kernels. Same kernel can be used
1501 as production kernel and capture kernel. Above option should have
1502 gone away after relocatable bzImage support is introduced. But it
1503 is present because there are users out there who continue to use
1504 vmlinux for dump capture. This option should go away down the
1507 Don't change this unless you know what you are doing.
1510 bool "Build a relocatable kernel"
1513 This builds a kernel image that retains relocation information
1514 so it can be loaded someplace besides the default 1MB.
1515 The relocations tend to make the kernel binary about 10% larger,
1516 but are discarded at runtime.
1518 One use is for the kexec on panic case where the recovery kernel
1519 must live at a different physical address than the primary
1522 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1523 it has been loaded at and the compile time physical address
1524 (CONFIG_PHYSICAL_START) is ignored.
1526 # Relocation on x86-32 needs some additional build support
1527 config X86_NEED_RELOCS
1529 depends on X86_32 && RELOCATABLE
1531 config PHYSICAL_ALIGN
1533 prompt "Alignment value to which kernel should be aligned" if X86_32
1535 range 0x2000 0x1000000
1537 This value puts the alignment restrictions on physical address
1538 where kernel is loaded and run from. Kernel is compiled for an
1539 address which meets above alignment restriction.
1541 If bootloader loads the kernel at a non-aligned address and
1542 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1543 address aligned to above value and run from there.
1545 If bootloader loads the kernel at a non-aligned address and
1546 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1547 load address and decompress itself to the address it has been
1548 compiled for and run from there. The address for which kernel is
1549 compiled already meets above alignment restrictions. Hence the
1550 end result is that kernel runs from a physical address meeting
1551 above alignment restrictions.
1553 Don't change this unless you know what you are doing.
1556 bool "Support for hot-pluggable CPUs"
1557 depends on SMP && HOTPLUG
1559 Say Y here to allow turning CPUs off and on. CPUs can be
1560 controlled through /sys/devices/system/cpu.
1561 ( Note: power management support will enable this option
1562 automatically on SMP systems. )
1563 Say N if you want to disable CPU hotplug.
1567 prompt "Compat VDSO support"
1568 depends on X86_32 || IA32_EMULATION
1570 Map the 32-bit VDSO to the predictable old-style address too.
1572 Say N here if you are running a sufficiently recent glibc
1573 version (2.3.3 or later), to remove the high-mapped
1574 VDSO mapping and to exclusively use the randomized VDSO.
1579 bool "Built-in kernel command line"
1582 Allow for specifying boot arguments to the kernel at
1583 build time. On some systems (e.g. embedded ones), it is
1584 necessary or convenient to provide some or all of the
1585 kernel boot arguments with the kernel itself (that is,
1586 to not rely on the boot loader to provide them.)
1588 To compile command line arguments into the kernel,
1589 set this option to 'Y', then fill in the
1590 the boot arguments in CONFIG_CMDLINE.
1592 Systems with fully functional boot loaders (i.e. non-embedded)
1593 should leave this option set to 'N'.
1596 string "Built-in kernel command string"
1597 depends on CMDLINE_BOOL
1600 Enter arguments here that should be compiled into the kernel
1601 image and used at boot time. If the boot loader provides a
1602 command line at boot time, it is appended to this string to
1603 form the full kernel command line, when the system boots.
1605 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1606 change this behavior.
1608 In most cases, the command line (whether built-in or provided
1609 by the boot loader) should specify the device for the root
1612 config CMDLINE_OVERRIDE
1613 bool "Built-in command line overrides boot loader arguments"
1615 depends on CMDLINE_BOOL
1617 Set this option to 'Y' to have the kernel ignore the boot loader
1618 command line, and use ONLY the built-in command line.
1620 This is used to work around broken boot loaders. This should
1621 be set to 'N' under normal conditions.
1625 config ARCH_ENABLE_MEMORY_HOTPLUG
1627 depends on X86_64 || (X86_32 && HIGHMEM)
1629 config ARCH_ENABLE_MEMORY_HOTREMOVE
1631 depends on MEMORY_HOTPLUG
1633 config HAVE_ARCH_EARLY_PFN_TO_NID
1637 menu "Power management and ACPI options"
1639 config ARCH_HIBERNATION_HEADER
1641 depends on X86_64 && HIBERNATION
1643 source "kernel/power/Kconfig"
1645 source "drivers/acpi/Kconfig"
1650 depends on APM || APM_MODULE
1653 tristate "APM (Advanced Power Management) BIOS support"
1654 depends on X86_32 && PM_SLEEP
1656 APM is a BIOS specification for saving power using several different
1657 techniques. This is mostly useful for battery powered laptops with
1658 APM compliant BIOSes. If you say Y here, the system time will be
1659 reset after a RESUME operation, the /proc/apm device will provide
1660 battery status information, and user-space programs will receive
1661 notification of APM "events" (e.g. battery status change).
1663 If you select "Y" here, you can disable actual use of the APM
1664 BIOS by passing the "apm=off" option to the kernel at boot time.
1666 Note that the APM support is almost completely disabled for
1667 machines with more than one CPU.
1669 In order to use APM, you will need supporting software. For location
1670 and more information, read <file:Documentation/power/pm.txt> and the
1671 Battery Powered Linux mini-HOWTO, available from
1672 <http://www.tldp.org/docs.html#howto>.
1674 This driver does not spin down disk drives (see the hdparm(8)
1675 manpage ("man 8 hdparm") for that), and it doesn't turn off
1676 VESA-compliant "green" monitors.
1678 This driver does not support the TI 4000M TravelMate and the ACER
1679 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1680 desktop machines also don't have compliant BIOSes, and this driver
1681 may cause those machines to panic during the boot phase.
1683 Generally, if you don't have a battery in your machine, there isn't
1684 much point in using this driver and you should say N. If you get
1685 random kernel OOPSes or reboots that don't seem to be related to
1686 anything, try disabling/enabling this option (or disabling/enabling
1689 Some other things you should try when experiencing seemingly random,
1692 1) make sure that you have enough swap space and that it is
1694 2) pass the "no-hlt" option to the kernel
1695 3) switch on floating point emulation in the kernel and pass
1696 the "no387" option to the kernel
1697 4) pass the "floppy=nodma" option to the kernel
1698 5) pass the "mem=4M" option to the kernel (thereby disabling
1699 all but the first 4 MB of RAM)
1700 6) make sure that the CPU is not over clocked.
1701 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1702 8) disable the cache from your BIOS settings
1703 9) install a fan for the video card or exchange video RAM
1704 10) install a better fan for the CPU
1705 11) exchange RAM chips
1706 12) exchange the motherboard.
1708 To compile this driver as a module, choose M here: the
1709 module will be called apm.
1713 config APM_IGNORE_USER_SUSPEND
1714 bool "Ignore USER SUSPEND"
1716 This option will ignore USER SUSPEND requests. On machines with a
1717 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1718 series notebooks, it is necessary to say Y because of a BIOS bug.
1720 config APM_DO_ENABLE
1721 bool "Enable PM at boot time"
1723 Enable APM features at boot time. From page 36 of the APM BIOS
1724 specification: "When disabled, the APM BIOS does not automatically
1725 power manage devices, enter the Standby State, enter the Suspend
1726 State, or take power saving steps in response to CPU Idle calls."
1727 This driver will make CPU Idle calls when Linux is idle (unless this
1728 feature is turned off -- see "Do CPU IDLE calls", below). This
1729 should always save battery power, but more complicated APM features
1730 will be dependent on your BIOS implementation. You may need to turn
1731 this option off if your computer hangs at boot time when using APM
1732 support, or if it beeps continuously instead of suspending. Turn
1733 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1734 T400CDT. This is off by default since most machines do fine without
1738 bool "Make CPU Idle calls when idle"
1740 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1741 On some machines, this can activate improved power savings, such as
1742 a slowed CPU clock rate, when the machine is idle. These idle calls
1743 are made after the idle loop has run for some length of time (e.g.,
1744 333 mS). On some machines, this will cause a hang at boot time or
1745 whenever the CPU becomes idle. (On machines with more than one CPU,
1746 this option does nothing.)
1748 config APM_DISPLAY_BLANK
1749 bool "Enable console blanking using APM"
1751 Enable console blanking using the APM. Some laptops can use this to
1752 turn off the LCD backlight when the screen blanker of the Linux
1753 virtual console blanks the screen. Note that this is only used by
1754 the virtual console screen blanker, and won't turn off the backlight
1755 when using the X Window system. This also doesn't have anything to
1756 do with your VESA-compliant power-saving monitor. Further, this
1757 option doesn't work for all laptops -- it might not turn off your
1758 backlight at all, or it might print a lot of errors to the console,
1759 especially if you are using gpm.
1761 config APM_ALLOW_INTS
1762 bool "Allow interrupts during APM BIOS calls"
1764 Normally we disable external interrupts while we are making calls to
1765 the APM BIOS as a measure to lessen the effects of a badly behaving
1766 BIOS implementation. The BIOS should reenable interrupts if it
1767 needs to. Unfortunately, some BIOSes do not -- especially those in
1768 many of the newer IBM Thinkpads. If you experience hangs when you
1769 suspend, try setting this to Y. Otherwise, say N.
1773 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1775 source "drivers/cpuidle/Kconfig"
1777 source "drivers/idle/Kconfig"
1782 menu "Bus options (PCI etc.)"
1787 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1789 Find out whether you have a PCI motherboard. PCI is the name of a
1790 bus system, i.e. the way the CPU talks to the other stuff inside
1791 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1792 VESA. If you have PCI, say Y, otherwise N.
1795 prompt "PCI access mode"
1796 depends on X86_32 && PCI
1799 On PCI systems, the BIOS can be used to detect the PCI devices and
1800 determine their configuration. However, some old PCI motherboards
1801 have BIOS bugs and may crash if this is done. Also, some embedded
1802 PCI-based systems don't have any BIOS at all. Linux can also try to
1803 detect the PCI hardware directly without using the BIOS.
1805 With this option, you can specify how Linux should detect the
1806 PCI devices. If you choose "BIOS", the BIOS will be used,
1807 if you choose "Direct", the BIOS won't be used, and if you
1808 choose "MMConfig", then PCI Express MMCONFIG will be used.
1809 If you choose "Any", the kernel will try MMCONFIG, then the
1810 direct access method and falls back to the BIOS if that doesn't
1811 work. If unsure, go with the default, which is "Any".
1816 config PCI_GOMMCONFIG
1833 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1835 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1838 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1842 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1846 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1853 bool "Support mmconfig PCI config space access"
1854 depends on X86_64 && PCI && ACPI
1857 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1858 depends on PCI_MSI && ACPI && EXPERIMENTAL
1860 DMA remapping (DMAR) devices support enables independent address
1861 translations for Direct Memory Access (DMA) from devices.
1862 These DMA remapping devices are reported via ACPI tables
1863 and include PCI device scope covered by these DMA
1866 config DMAR_DEFAULT_ON
1868 prompt "Enable DMA Remapping Devices by default"
1871 Selecting this option will enable a DMAR device at boot time if
1872 one is found. If this option is not selected, DMAR support can
1873 be enabled by passing intel_iommu=on to the kernel. It is
1874 recommended you say N here while the DMAR code remains
1879 prompt "Support for Graphics workaround"
1882 Current Graphics drivers tend to use physical address
1883 for DMA and avoid using DMA APIs. Setting this config
1884 option permits the IOMMU driver to set a unity map for
1885 all the OS-visible memory. Hence the driver can continue
1886 to use physical addresses for DMA.
1888 config DMAR_FLOPPY_WA
1892 Floppy disk drivers are know to bypass DMA API calls
1893 thereby failing to work when IOMMU is enabled. This
1894 workaround will setup a 1:1 mapping for the first
1895 16M to make floppy (an ISA device) work.
1898 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1899 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1901 Supports Interrupt remapping for IO-APIC and MSI devices.
1902 To use x2apic mode in the CPU's which support x2APIC enhancements or
1903 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1905 source "drivers/pci/pcie/Kconfig"
1907 source "drivers/pci/Kconfig"
1909 # x86_64 have no ISA slots, but do have ISA-style DMA.
1918 Find out whether you have ISA slots on your motherboard. ISA is the
1919 name of a bus system, i.e. the way the CPU talks to the other stuff
1920 inside your box. Other bus systems are PCI, EISA, MicroChannel
1921 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1922 newer boards don't support it. If you have ISA, say Y, otherwise N.
1928 The Extended Industry Standard Architecture (EISA) bus was
1929 developed as an open alternative to the IBM MicroChannel bus.
1931 The EISA bus provided some of the features of the IBM MicroChannel
1932 bus while maintaining backward compatibility with cards made for
1933 the older ISA bus. The EISA bus saw limited use between 1988 and
1934 1995 when it was made obsolete by the PCI bus.
1936 Say Y here if you are building a kernel for an EISA-based machine.
1940 source "drivers/eisa/Kconfig"
1945 MicroChannel Architecture is found in some IBM PS/2 machines and
1946 laptops. It is a bus system similar to PCI or ISA. See
1947 <file:Documentation/mca.txt> (and especially the web page given
1948 there) before attempting to build an MCA bus kernel.
1950 source "drivers/mca/Kconfig"
1953 tristate "NatSemi SCx200 support"
1955 This provides basic support for National Semiconductor's
1956 (now AMD's) Geode processors. The driver probes for the
1957 PCI-IDs of several on-chip devices, so its a good dependency
1958 for other scx200_* drivers.
1960 If compiled as a module, the driver is named scx200.
1962 config SCx200HR_TIMER
1963 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1964 depends on SCx200 && GENERIC_TIME
1967 This driver provides a clocksource built upon the on-chip
1968 27MHz high-resolution timer. Its also a workaround for
1969 NSC Geode SC-1100's buggy TSC, which loses time when the
1970 processor goes idle (as is done by the scheduler). The
1971 other workaround is idle=poll boot option.
1973 config GEODE_MFGPT_TIMER
1975 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1976 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1978 This driver provides a clock event source based on the MFGPT
1979 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1980 MFGPTs have a better resolution and max interval than the
1981 generic PIT, and are suitable for use as high-res timers.
1984 bool "One Laptop Per Child support"
1987 Add support for detecting the unique features of the OLPC
1994 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1996 source "drivers/pcmcia/Kconfig"
1998 source "drivers/pci/hotplug/Kconfig"
2003 menu "Executable file formats / Emulations"
2005 source "fs/Kconfig.binfmt"
2007 config IA32_EMULATION
2008 bool "IA32 Emulation"
2010 select COMPAT_BINFMT_ELF
2012 Include code to run 32-bit programs under a 64-bit kernel. You should
2013 likely turn this on, unless you're 100% sure that you don't have any
2014 32-bit programs left.
2017 tristate "IA32 a.out support"
2018 depends on IA32_EMULATION
2020 Support old a.out binaries in the 32bit emulation.
2024 depends on IA32_EMULATION
2026 config COMPAT_FOR_U64_ALIGNMENT
2030 config SYSVIPC_COMPAT
2032 depends on COMPAT && SYSVIPC
2037 config HAVE_ATOMIC_IOMAP
2041 source "net/Kconfig"
2043 source "drivers/Kconfig"
2045 source "drivers/firmware/Kconfig"
2049 source "arch/x86/Kconfig.debug"
2051 source "security/Kconfig"
2053 source "crypto/Kconfig"
2055 source "arch/x86/kvm/Kconfig"
2057 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob