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_CLOCK
507 config PARAVIRT_DEBUG
508 bool "paravirt-ops debugging"
509 depends on PARAVIRT && DEBUG_KERNEL
511 Enable to debug paravirt_ops internals. Specifically, BUG if
512 a paravirt_op is missing when it is called.
517 This option adds a kernel parameter 'memtest', which allows memtest
519 memtest=0, mean disabled; -- default
520 memtest=1, mean do 1 test pattern;
522 memtest=4, mean do 4 test patterns.
523 If you are unsure how to answer this question, answer N.
525 config X86_SUMMIT_NUMA
527 depends on X86_32 && NUMA && X86_32_NON_STANDARD
529 config X86_CYCLONE_TIMER
531 depends on X86_32_NON_STANDARD
533 source "arch/x86/Kconfig.cpu"
537 prompt "HPET Timer Support" if X86_32
539 Use the IA-PC HPET (High Precision Event Timer) to manage
540 time in preference to the PIT and RTC, if a HPET is
542 HPET is the next generation timer replacing legacy 8254s.
543 The HPET provides a stable time base on SMP
544 systems, unlike the TSC, but it is more expensive to access,
545 as it is off-chip. You can find the HPET spec at
546 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
548 You can safely choose Y here. However, HPET will only be
549 activated if the platform and the BIOS support this feature.
550 Otherwise the 8254 will be used for timing services.
552 Choose N to continue using the legacy 8254 timer.
554 config HPET_EMULATE_RTC
556 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
558 # Mark as embedded because too many people got it wrong.
559 # The code disables itself when not needed.
562 bool "Enable DMI scanning" if EMBEDDED
564 Enabled scanning of DMI to identify machine quirks. Say Y
565 here unless you have verified that your setup is not
566 affected by entries in the DMI blacklist. Required by PNP
570 bool "GART IOMMU support" if EMBEDDED
574 depends on X86_64 && PCI
576 Support for full DMA access of devices with 32bit memory access only
577 on systems with more than 3GB. This is usually needed for USB,
578 sound, many IDE/SATA chipsets and some other devices.
579 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
580 based hardware IOMMU and a software bounce buffer based IOMMU used
581 on Intel systems and as fallback.
582 The code is only active when needed (enough memory and limited
583 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
587 bool "IBM Calgary IOMMU support"
589 depends on X86_64 && PCI && EXPERIMENTAL
591 Support for hardware IOMMUs in IBM's xSeries x366 and x460
592 systems. Needed to run systems with more than 3GB of memory
593 properly with 32-bit PCI devices that do not support DAC
594 (Double Address Cycle). Calgary also supports bus level
595 isolation, where all DMAs pass through the IOMMU. This
596 prevents them from going anywhere except their intended
597 destination. This catches hard-to-find kernel bugs and
598 mis-behaving drivers and devices that do not use the DMA-API
599 properly to set up their DMA buffers. The IOMMU can be
600 turned off at boot time with the iommu=off parameter.
601 Normally the kernel will make the right choice by itself.
604 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
606 prompt "Should Calgary be enabled by default?"
607 depends on CALGARY_IOMMU
609 Should Calgary be enabled by default? if you choose 'y', Calgary
610 will be used (if it exists). If you choose 'n', Calgary will not be
611 used even if it exists. If you choose 'n' and would like to use
612 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
616 bool "AMD IOMMU support"
619 depends on X86_64 && PCI && ACPI
621 With this option you can enable support for AMD IOMMU hardware in
622 your system. An IOMMU is a hardware component which provides
623 remapping of DMA memory accesses from devices. With an AMD IOMMU you
624 can isolate the the DMA memory of different devices and protect the
625 system from misbehaving device drivers or hardware.
627 You can find out if your system has an AMD IOMMU if you look into
628 your BIOS for an option to enable it or if you have an IVRS ACPI
631 config AMD_IOMMU_STATS
632 bool "Export AMD IOMMU statistics to debugfs"
636 This option enables code in the AMD IOMMU driver to collect various
637 statistics about whats happening in the driver and exports that
638 information to userspace via debugfs.
641 # need this always selected by IOMMU for the VIA workaround
645 Support for software bounce buffers used on x86-64 systems
646 which don't have a hardware IOMMU (e.g. the current generation
647 of Intel's x86-64 CPUs). Using this PCI devices which can only
648 access 32-bits of memory can be used on systems with more than
649 3 GB of memory. If unsure, say Y.
652 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
655 def_bool (AMD_IOMMU || DMAR)
658 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
659 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
660 select CPUMASK_OFFSTACK
663 Configure maximum number of CPUS and NUMA Nodes for this architecture.
667 int "Maximum number of CPUs" if SMP && !MAXSMP
668 range 2 8 if SMP && X86_32 && !X86_BIGSMP
669 range 2 512 if SMP && !MAXSMP
671 default "4096" if MAXSMP
672 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
675 This allows you to specify the maximum number of CPUs which this
676 kernel will support. The maximum supported value is 512 and the
677 minimum value which makes sense is 2.
679 This is purely to save memory - each supported CPU adds
680 approximately eight kilobytes to the kernel image.
683 bool "SMT (Hyperthreading) scheduler support"
686 SMT scheduler support improves the CPU scheduler's decision making
687 when dealing with Intel Pentium 4 chips with HyperThreading at a
688 cost of slightly increased overhead in some places. If unsure say
693 prompt "Multi-core scheduler support"
696 Multi-core scheduler support improves the CPU scheduler's decision
697 making when dealing with multi-core CPU chips at a cost of slightly
698 increased overhead in some places. If unsure say N here.
700 source "kernel/Kconfig.preempt"
703 bool "Local APIC support on uniprocessors"
704 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
706 A local APIC (Advanced Programmable Interrupt Controller) is an
707 integrated interrupt controller in the CPU. If you have a single-CPU
708 system which has a processor with a local APIC, you can say Y here to
709 enable and use it. If you say Y here even though your machine doesn't
710 have a local APIC, then the kernel will still run with no slowdown at
711 all. The local APIC supports CPU-generated self-interrupts (timer,
712 performance counters), and the NMI watchdog which detects hard
716 bool "IO-APIC support on uniprocessors"
717 depends on X86_UP_APIC
719 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
720 SMP-capable replacement for PC-style interrupt controllers. Most
721 SMP systems and many recent uniprocessor systems have one.
723 If you have a single-CPU system with an IO-APIC, you can say Y here
724 to use it. If you say Y here even though your machine doesn't have
725 an IO-APIC, then the kernel will still run with no slowdown at all.
727 config X86_LOCAL_APIC
729 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
733 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
735 config X86_VISWS_APIC
737 depends on X86_32 && X86_VISWS
739 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
740 bool "Reroute for broken boot IRQs"
742 depends on X86_IO_APIC
744 This option enables a workaround that fixes a source of
745 spurious interrupts. This is recommended when threaded
746 interrupt handling is used on systems where the generation of
747 superfluous "boot interrupts" cannot be disabled.
749 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
750 entry in the chipset's IO-APIC is masked (as, e.g. the RT
751 kernel does during interrupt handling). On chipsets where this
752 boot IRQ generation cannot be disabled, this workaround keeps
753 the original IRQ line masked so that only the equivalent "boot
754 IRQ" is delivered to the CPUs. The workaround also tells the
755 kernel to set up the IRQ handler on the boot IRQ line. In this
756 way only one interrupt is delivered to the kernel. Otherwise
757 the spurious second interrupt may cause the kernel to bring
758 down (vital) interrupt lines.
760 Only affects "broken" chipsets. Interrupt sharing may be
761 increased on these systems.
764 bool "Machine Check Exception"
766 Machine Check Exception support allows the processor to notify the
767 kernel if it detects a problem (e.g. overheating, component failure).
768 The action the kernel takes depends on the severity of the problem,
769 ranging from a warning message on the console, to halting the machine.
770 Your processor must be a Pentium or newer to support this - check the
771 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
772 have a design flaw which leads to false MCE events - hence MCE is
773 disabled on all P5 processors, unless explicitly enabled with "mce"
774 as a boot argument. Similarly, if MCE is built in and creates a
775 problem on some new non-standard machine, you can boot with "nomce"
776 to disable it. MCE support simply ignores non-MCE processors like
777 the 386 and 486, so nearly everyone can say Y here.
781 prompt "Intel MCE features"
782 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
784 Additional support for intel specific MCE features such as
789 prompt "AMD MCE features"
790 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
792 Additional support for AMD specific MCE features such as
793 the DRAM Error Threshold.
795 config X86_MCE_THRESHOLD
796 depends on X86_MCE_AMD || X86_MCE_INTEL
800 config X86_MCE_NONFATAL
801 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
802 depends on X86_32 && X86_MCE
804 Enabling this feature starts a timer that triggers every 5 seconds which
805 will look at the machine check registers to see if anything happened.
806 Non-fatal problems automatically get corrected (but still logged).
807 Disable this if you don't want to see these messages.
808 Seeing the messages this option prints out may be indicative of dying
809 or out-of-spec (ie, overclocked) hardware.
810 This option only does something on certain CPUs.
811 (AMD Athlon/Duron and Intel Pentium 4)
813 config X86_MCE_P4THERMAL
814 bool "check for P4 thermal throttling interrupt."
815 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
817 Enabling this feature will cause a message to be printed when the P4
818 enters thermal throttling.
821 bool "Enable VM86 support" if EMBEDDED
825 This option is required by programs like DOSEMU to run 16-bit legacy
826 code on X86 processors. It also may be needed by software like
827 XFree86 to initialize some video cards via BIOS. Disabling this
828 option saves about 6k.
831 tristate "Toshiba Laptop support"
834 This adds a driver to safely access the System Management Mode of
835 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
836 not work on models with a Phoenix BIOS. The System Management Mode
837 is used to set the BIOS and power saving options on Toshiba portables.
839 For information on utilities to make use of this driver see the
840 Toshiba Linux utilities web site at:
841 <http://www.buzzard.org.uk/toshiba/>.
843 Say Y if you intend to run this kernel on a Toshiba portable.
847 tristate "Dell laptop support"
849 This adds a driver to safely access the System Management Mode
850 of the CPU on the Dell Inspiron 8000. The System Management Mode
851 is used to read cpu temperature and cooling fan status and to
852 control the fans on the I8K portables.
854 This driver has been tested only on the Inspiron 8000 but it may
855 also work with other Dell laptops. You can force loading on other
856 models by passing the parameter `force=1' to the module. Use at
859 For information on utilities to make use of this driver see the
860 I8K Linux utilities web site at:
861 <http://people.debian.org/~dz/i8k/>
863 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
866 config X86_REBOOTFIXUPS
867 bool "Enable X86 board specific fixups for reboot"
870 This enables chipset and/or board specific fixups to be done
871 in order to get reboot to work correctly. This is only needed on
872 some combinations of hardware and BIOS. The symptom, for which
873 this config is intended, is when reboot ends with a stalled/hung
876 Currently, the only fixup is for the Geode machines using
877 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
879 Say Y if you want to enable the fixup. Currently, it's safe to
880 enable this option even if you don't need it.
884 tristate "/dev/cpu/microcode - microcode support"
887 If you say Y here, you will be able to update the microcode on
888 certain Intel and AMD processors. The Intel support is for the
889 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
890 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
891 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
892 You will obviously need the actual microcode binary data itself
893 which is not shipped with the Linux kernel.
895 This option selects the general module only, you need to select
896 at least one vendor specific module as well.
898 To compile this driver as a module, choose M here: the
899 module will be called microcode.
901 config MICROCODE_INTEL
902 bool "Intel microcode patch loading support"
907 This options enables microcode patch loading support for Intel
910 For latest news and information on obtaining all the required
911 Intel ingredients for this driver, check:
912 <http://www.urbanmyth.org/microcode/>.
915 bool "AMD microcode patch loading support"
919 If you select this option, microcode patch loading support for AMD
920 processors will be enabled.
922 config MICROCODE_OLD_INTERFACE
927 tristate "/dev/cpu/*/msr - Model-specific register support"
929 This device gives privileged processes access to the x86
930 Model-Specific Registers (MSRs). It is a character device with
931 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
932 MSR accesses are directed to a specific CPU on multi-processor
936 tristate "/dev/cpu/*/cpuid - CPU information support"
938 This device gives processes access to the x86 CPUID instruction to
939 be executed on a specific processor. It is a character device
940 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
944 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
946 If you select this option, this will provide various x86 CPUs
947 information through debugfs.
950 prompt "High Memory Support"
951 default HIGHMEM4G if !X86_NUMAQ
952 default HIGHMEM64G if X86_NUMAQ
957 depends on !X86_NUMAQ
959 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
960 However, the address space of 32-bit x86 processors is only 4
961 Gigabytes large. That means that, if you have a large amount of
962 physical memory, not all of it can be "permanently mapped" by the
963 kernel. The physical memory that's not permanently mapped is called
966 If you are compiling a kernel which will never run on a machine with
967 more than 1 Gigabyte total physical RAM, answer "off" here (default
968 choice and suitable for most users). This will result in a "3GB/1GB"
969 split: 3GB are mapped so that each process sees a 3GB virtual memory
970 space and the remaining part of the 4GB virtual memory space is used
971 by the kernel to permanently map as much physical memory as
974 If the machine has between 1 and 4 Gigabytes physical RAM, then
977 If more than 4 Gigabytes is used then answer "64GB" here. This
978 selection turns Intel PAE (Physical Address Extension) mode on.
979 PAE implements 3-level paging on IA32 processors. PAE is fully
980 supported by Linux, PAE mode is implemented on all recent Intel
981 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
982 then the kernel will not boot on CPUs that don't support PAE!
984 The actual amount of total physical memory will either be
985 auto detected or can be forced by using a kernel command line option
986 such as "mem=256M". (Try "man bootparam" or see the documentation of
987 your boot loader (lilo or loadlin) about how to pass options to the
988 kernel at boot time.)
990 If unsure, say "off".
994 depends on !X86_NUMAQ
996 Select this if you have a 32-bit processor and between 1 and 4
997 gigabytes of physical RAM.
1001 depends on !M386 && !M486
1004 Select this if you have a 32-bit processor and more than 4
1005 gigabytes of physical RAM.
1010 depends on EXPERIMENTAL
1011 prompt "Memory split" if EMBEDDED
1015 Select the desired split between kernel and user memory.
1017 If the address range available to the kernel is less than the
1018 physical memory installed, the remaining memory will be available
1019 as "high memory". Accessing high memory is a little more costly
1020 than low memory, as it needs to be mapped into the kernel first.
1021 Note that increasing the kernel address space limits the range
1022 available to user programs, making the address space there
1023 tighter. Selecting anything other than the default 3G/1G split
1024 will also likely make your kernel incompatible with binary-only
1027 If you are not absolutely sure what you are doing, leave this
1031 bool "3G/1G user/kernel split"
1032 config VMSPLIT_3G_OPT
1034 bool "3G/1G user/kernel split (for full 1G low memory)"
1036 bool "2G/2G user/kernel split"
1037 config VMSPLIT_2G_OPT
1039 bool "2G/2G user/kernel split (for full 2G low memory)"
1041 bool "1G/3G user/kernel split"
1046 default 0xB0000000 if VMSPLIT_3G_OPT
1047 default 0x80000000 if VMSPLIT_2G
1048 default 0x78000000 if VMSPLIT_2G_OPT
1049 default 0x40000000 if VMSPLIT_1G
1055 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1058 bool "PAE (Physical Address Extension) Support"
1059 depends on X86_32 && !HIGHMEM4G
1061 PAE is required for NX support, and furthermore enables
1062 larger swapspace support for non-overcommit purposes. It
1063 has the cost of more pagetable lookup overhead, and also
1064 consumes more pagetable space per process.
1066 config ARCH_PHYS_ADDR_T_64BIT
1067 def_bool X86_64 || X86_PAE
1069 config DIRECT_GBPAGES
1070 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1074 Allow the kernel linear mapping to use 1GB pages on CPUs that
1075 support it. This can improve the kernel's performance a tiny bit by
1076 reducing TLB pressure. If in doubt, say "Y".
1078 # Common NUMA Features
1080 bool "Numa Memory Allocation and Scheduler Support"
1082 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1083 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1085 Enable NUMA (Non Uniform Memory Access) support.
1087 The kernel will try to allocate memory used by a CPU on the
1088 local memory controller of the CPU and add some more
1089 NUMA awareness to the kernel.
1091 For 64-bit this is recommended if the system is Intel Core i7
1092 (or later), AMD Opteron, or EM64T NUMA.
1094 For 32-bit this is only needed on (rare) 32-bit-only platforms
1095 that support NUMA topologies, such as NUMAQ / Summit, or if you
1096 boot a 32-bit kernel on a 64-bit NUMA platform.
1098 Otherwise, you should say N.
1100 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1101 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1105 prompt "Old style AMD Opteron NUMA detection"
1106 depends on X86_64 && NUMA && PCI
1108 Enable K8 NUMA node topology detection. You should say Y here if
1109 you have a multi processor AMD K8 system. This uses an old
1110 method to read the NUMA configuration directly from the builtin
1111 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1112 instead, which also takes priority if both are compiled in.
1114 config X86_64_ACPI_NUMA
1116 prompt "ACPI NUMA detection"
1117 depends on X86_64 && NUMA && ACPI && PCI
1120 Enable ACPI SRAT based node topology detection.
1122 # Some NUMA nodes have memory ranges that span
1123 # other nodes. Even though a pfn is valid and
1124 # between a node's start and end pfns, it may not
1125 # reside on that node. See memmap_init_zone()
1127 config NODES_SPAN_OTHER_NODES
1129 depends on X86_64_ACPI_NUMA
1132 bool "NUMA emulation"
1133 depends on X86_64 && NUMA
1135 Enable NUMA emulation. A flat machine will be split
1136 into virtual nodes when booted with "numa=fake=N", where N is the
1137 number of nodes. This is only useful for debugging.
1140 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1142 default "9" if MAXSMP
1143 default "6" if X86_64
1144 default "4" if X86_NUMAQ
1146 depends on NEED_MULTIPLE_NODES
1148 Specify the maximum number of NUMA Nodes available on the target
1149 system. Increases memory reserved to accommodate various tables.
1151 config HAVE_ARCH_BOOTMEM
1153 depends on X86_32 && NUMA
1155 config ARCH_HAVE_MEMORY_PRESENT
1157 depends on X86_32 && DISCONTIGMEM
1159 config NEED_NODE_MEMMAP_SIZE
1161 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1163 config HAVE_ARCH_ALLOC_REMAP
1165 depends on X86_32 && NUMA
1167 config ARCH_FLATMEM_ENABLE
1169 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1171 config ARCH_DISCONTIGMEM_ENABLE
1173 depends on NUMA && X86_32
1175 config ARCH_DISCONTIGMEM_DEFAULT
1177 depends on NUMA && X86_32
1179 config ARCH_SPARSEMEM_DEFAULT
1183 config ARCH_SPARSEMEM_ENABLE
1185 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1186 select SPARSEMEM_STATIC if X86_32
1187 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1189 config ARCH_SELECT_MEMORY_MODEL
1191 depends on ARCH_SPARSEMEM_ENABLE
1193 config ARCH_MEMORY_PROBE
1195 depends on MEMORY_HOTPLUG
1200 bool "Allocate 3rd-level pagetables from highmem"
1201 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1203 The VM uses one page table entry for each page of physical memory.
1204 For systems with a lot of RAM, this can be wasteful of precious
1205 low memory. Setting this option will put user-space page table
1206 entries in high memory.
1208 config X86_CHECK_BIOS_CORRUPTION
1209 bool "Check for low memory corruption"
1211 Periodically check for memory corruption in low memory, which
1212 is suspected to be caused by BIOS. Even when enabled in the
1213 configuration, it is disabled at runtime. Enable it by
1214 setting "memory_corruption_check=1" on the kernel command
1215 line. By default it scans the low 64k of memory every 60
1216 seconds; see the memory_corruption_check_size and
1217 memory_corruption_check_period parameters in
1218 Documentation/kernel-parameters.txt to adjust this.
1220 When enabled with the default parameters, this option has
1221 almost no overhead, as it reserves a relatively small amount
1222 of memory and scans it infrequently. It both detects corruption
1223 and prevents it from affecting the running system.
1225 It is, however, intended as a diagnostic tool; if repeatable
1226 BIOS-originated corruption always affects the same memory,
1227 you can use memmap= to prevent the kernel from using that
1230 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1231 bool "Set the default setting of memory_corruption_check"
1232 depends on X86_CHECK_BIOS_CORRUPTION
1235 Set whether the default state of memory_corruption_check is
1238 config X86_RESERVE_LOW_64K
1239 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1242 Reserve the first 64K of physical RAM on BIOSes that are known
1243 to potentially corrupt that memory range. A numbers of BIOSes are
1244 known to utilize this area during suspend/resume, so it must not
1245 be used by the kernel.
1247 Set this to N if you are absolutely sure that you trust the BIOS
1248 to get all its memory reservations and usages right.
1250 If you have doubts about the BIOS (e.g. suspend/resume does not
1251 work or there's kernel crashes after certain hardware hotplug
1252 events) and it's not AMI or Phoenix, then you might want to enable
1253 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1254 corruption patterns.
1258 config MATH_EMULATION
1260 prompt "Math emulation" if X86_32
1262 Linux can emulate a math coprocessor (used for floating point
1263 operations) if you don't have one. 486DX and Pentium processors have
1264 a math coprocessor built in, 486SX and 386 do not, unless you added
1265 a 487DX or 387, respectively. (The messages during boot time can
1266 give you some hints here ["man dmesg"].) Everyone needs either a
1267 coprocessor or this emulation.
1269 If you don't have a math coprocessor, you need to say Y here; if you
1270 say Y here even though you have a coprocessor, the coprocessor will
1271 be used nevertheless. (This behavior can be changed with the kernel
1272 command line option "no387", which comes handy if your coprocessor
1273 is broken. Try "man bootparam" or see the documentation of your boot
1274 loader (lilo or loadlin) about how to pass options to the kernel at
1275 boot time.) This means that it is a good idea to say Y here if you
1276 intend to use this kernel on different machines.
1278 More information about the internals of the Linux math coprocessor
1279 emulation can be found in <file:arch/x86/math-emu/README>.
1281 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1282 kernel, it won't hurt.
1285 bool "MTRR (Memory Type Range Register) support"
1287 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1288 the Memory Type Range Registers (MTRRs) may be used to control
1289 processor access to memory ranges. This is most useful if you have
1290 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1291 allows bus write transfers to be combined into a larger transfer
1292 before bursting over the PCI/AGP bus. This can increase performance
1293 of image write operations 2.5 times or more. Saying Y here creates a
1294 /proc/mtrr file which may be used to manipulate your processor's
1295 MTRRs. Typically the X server should use this.
1297 This code has a reasonably generic interface so that similar
1298 control registers on other processors can be easily supported
1301 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1302 Registers (ARRs) which provide a similar functionality to MTRRs. For
1303 these, the ARRs are used to emulate the MTRRs.
1304 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1305 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1306 write-combining. All of these processors are supported by this code
1307 and it makes sense to say Y here if you have one of them.
1309 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1310 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1311 can lead to all sorts of problems, so it's good to say Y here.
1313 You can safely say Y even if your machine doesn't have MTRRs, you'll
1314 just add about 9 KB to your kernel.
1316 See <file:Documentation/x86/mtrr.txt> for more information.
1318 config MTRR_SANITIZER
1320 prompt "MTRR cleanup support"
1323 Convert MTRR layout from continuous to discrete, so X drivers can
1324 add writeback entries.
1326 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1327 The largest mtrr entry size for a continuous block can be set with
1332 config MTRR_SANITIZER_ENABLE_DEFAULT
1333 int "MTRR cleanup enable value (0-1)"
1336 depends on MTRR_SANITIZER
1338 Enable mtrr cleanup default value
1340 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1341 int "MTRR cleanup spare reg num (0-7)"
1344 depends on MTRR_SANITIZER
1346 mtrr cleanup spare entries default, it can be changed via
1347 mtrr_spare_reg_nr=N on the kernel command line.
1351 prompt "x86 PAT support"
1354 Use PAT attributes to setup page level cache control.
1356 PATs are the modern equivalents of MTRRs and are much more
1357 flexible than MTRRs.
1359 Say N here if you see bootup problems (boot crash, boot hang,
1360 spontaneous reboots) or a non-working video driver.
1365 bool "EFI runtime service support"
1368 This enables the kernel to use EFI runtime services that are
1369 available (such as the EFI variable services).
1371 This option is only useful on systems that have EFI firmware.
1372 In addition, you should use the latest ELILO loader available
1373 at <http://elilo.sourceforge.net> in order to take advantage
1374 of EFI runtime services. However, even with this option, the
1375 resultant kernel should continue to boot on existing non-EFI
1380 prompt "Enable seccomp to safely compute untrusted bytecode"
1382 This kernel feature is useful for number crunching applications
1383 that may need to compute untrusted bytecode during their
1384 execution. By using pipes or other transports made available to
1385 the process as file descriptors supporting the read/write
1386 syscalls, it's possible to isolate those applications in
1387 their own address space using seccomp. Once seccomp is
1388 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1389 and the task is only allowed to execute a few safe syscalls
1390 defined by each seccomp mode.
1392 If unsure, say Y. Only embedded should say N here.
1394 config CC_STACKPROTECTOR_ALL
1397 config CC_STACKPROTECTOR
1398 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1399 select CC_STACKPROTECTOR_ALL
1401 This option turns on the -fstack-protector GCC feature. This
1402 feature puts, at the beginning of functions, a canary value on
1403 the stack just before the return address, and validates
1404 the value just before actually returning. Stack based buffer
1405 overflows (that need to overwrite this return address) now also
1406 overwrite the canary, which gets detected and the attack is then
1407 neutralized via a kernel panic.
1409 This feature requires gcc version 4.2 or above, or a distribution
1410 gcc with the feature backported. Older versions are automatically
1411 detected and for those versions, this configuration option is
1412 ignored. (and a warning is printed during bootup)
1414 source kernel/Kconfig.hz
1417 bool "kexec system call"
1419 kexec is a system call that implements the ability to shutdown your
1420 current kernel, and to start another kernel. It is like a reboot
1421 but it is independent of the system firmware. And like a reboot
1422 you can start any kernel with it, not just Linux.
1424 The name comes from the similarity to the exec system call.
1426 It is an ongoing process to be certain the hardware in a machine
1427 is properly shutdown, so do not be surprised if this code does not
1428 initially work for you. It may help to enable device hotplugging
1429 support. As of this writing the exact hardware interface is
1430 strongly in flux, so no good recommendation can be made.
1433 bool "kernel crash dumps"
1434 depends on X86_64 || (X86_32 && HIGHMEM)
1436 Generate crash dump after being started by kexec.
1437 This should be normally only set in special crash dump kernels
1438 which are loaded in the main kernel with kexec-tools into
1439 a specially reserved region and then later executed after
1440 a crash by kdump/kexec. The crash dump kernel must be compiled
1441 to a memory address not used by the main kernel or BIOS using
1442 PHYSICAL_START, or it must be built as a relocatable image
1443 (CONFIG_RELOCATABLE=y).
1444 For more details see Documentation/kdump/kdump.txt
1447 bool "kexec jump (EXPERIMENTAL)"
1448 depends on EXPERIMENTAL
1449 depends on KEXEC && HIBERNATION
1451 Jump between original kernel and kexeced kernel and invoke
1452 code in physical address mode via KEXEC
1454 config PHYSICAL_START
1455 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1456 default "0x1000000" if X86_NUMAQ
1457 default "0x200000" if X86_64
1460 This gives the physical address where the kernel is loaded.
1462 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1463 bzImage will decompress itself to above physical address and
1464 run from there. Otherwise, bzImage will run from the address where
1465 it has been loaded by the boot loader and will ignore above physical
1468 In normal kdump cases one does not have to set/change this option
1469 as now bzImage can be compiled as a completely relocatable image
1470 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1471 address. This option is mainly useful for the folks who don't want
1472 to use a bzImage for capturing the crash dump and want to use a
1473 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1474 to be specifically compiled to run from a specific memory area
1475 (normally a reserved region) and this option comes handy.
1477 So if you are using bzImage for capturing the crash dump, leave
1478 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1479 Otherwise if you plan to use vmlinux for capturing the crash dump
1480 change this value to start of the reserved region (Typically 16MB
1481 0x1000000). In other words, it can be set based on the "X" value as
1482 specified in the "crashkernel=YM@XM" command line boot parameter
1483 passed to the panic-ed kernel. Typically this parameter is set as
1484 crashkernel=64M@16M. Please take a look at
1485 Documentation/kdump/kdump.txt for more details about crash dumps.
1487 Usage of bzImage for capturing the crash dump is recommended as
1488 one does not have to build two kernels. Same kernel can be used
1489 as production kernel and capture kernel. Above option should have
1490 gone away after relocatable bzImage support is introduced. But it
1491 is present because there are users out there who continue to use
1492 vmlinux for dump capture. This option should go away down the
1495 Don't change this unless you know what you are doing.
1498 bool "Build a relocatable kernel (EXPERIMENTAL)"
1499 depends on EXPERIMENTAL
1501 This builds a kernel image that retains relocation information
1502 so it can be loaded someplace besides the default 1MB.
1503 The relocations tend to make the kernel binary about 10% larger,
1504 but are discarded at runtime.
1506 One use is for the kexec on panic case where the recovery kernel
1507 must live at a different physical address than the primary
1510 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1511 it has been loaded at and the compile time physical address
1512 (CONFIG_PHYSICAL_START) is ignored.
1514 config PHYSICAL_ALIGN
1516 prompt "Alignment value to which kernel should be aligned" if X86_32
1517 default "0x100000" if X86_32
1518 default "0x200000" if X86_64
1519 range 0x2000 0x400000
1521 This value puts the alignment restrictions on physical address
1522 where kernel is loaded and run from. Kernel is compiled for an
1523 address which meets above alignment restriction.
1525 If bootloader loads the kernel at a non-aligned address and
1526 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1527 address aligned to above value and run from there.
1529 If bootloader loads the kernel at a non-aligned address and
1530 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1531 load address and decompress itself to the address it has been
1532 compiled for and run from there. The address for which kernel is
1533 compiled already meets above alignment restrictions. Hence the
1534 end result is that kernel runs from a physical address meeting
1535 above alignment restrictions.
1537 Don't change this unless you know what you are doing.
1540 bool "Support for hot-pluggable CPUs"
1541 depends on SMP && HOTPLUG
1543 Say Y here to allow turning CPUs off and on. CPUs can be
1544 controlled through /sys/devices/system/cpu.
1545 ( Note: power management support will enable this option
1546 automatically on SMP systems. )
1547 Say N if you want to disable CPU hotplug.
1551 prompt "Compat VDSO support"
1552 depends on X86_32 || IA32_EMULATION
1554 Map the 32-bit VDSO to the predictable old-style address too.
1556 Say N here if you are running a sufficiently recent glibc
1557 version (2.3.3 or later), to remove the high-mapped
1558 VDSO mapping and to exclusively use the randomized VDSO.
1563 bool "Built-in kernel command line"
1566 Allow for specifying boot arguments to the kernel at
1567 build time. On some systems (e.g. embedded ones), it is
1568 necessary or convenient to provide some or all of the
1569 kernel boot arguments with the kernel itself (that is,
1570 to not rely on the boot loader to provide them.)
1572 To compile command line arguments into the kernel,
1573 set this option to 'Y', then fill in the
1574 the boot arguments in CONFIG_CMDLINE.
1576 Systems with fully functional boot loaders (i.e. non-embedded)
1577 should leave this option set to 'N'.
1580 string "Built-in kernel command string"
1581 depends on CMDLINE_BOOL
1584 Enter arguments here that should be compiled into the kernel
1585 image and used at boot time. If the boot loader provides a
1586 command line at boot time, it is appended to this string to
1587 form the full kernel command line, when the system boots.
1589 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1590 change this behavior.
1592 In most cases, the command line (whether built-in or provided
1593 by the boot loader) should specify the device for the root
1596 config CMDLINE_OVERRIDE
1597 bool "Built-in command line overrides boot loader arguments"
1599 depends on CMDLINE_BOOL
1601 Set this option to 'Y' to have the kernel ignore the boot loader
1602 command line, and use ONLY the built-in command line.
1604 This is used to work around broken boot loaders. This should
1605 be set to 'N' under normal conditions.
1609 config ARCH_ENABLE_MEMORY_HOTPLUG
1611 depends on X86_64 || (X86_32 && HIGHMEM)
1613 config ARCH_ENABLE_MEMORY_HOTREMOVE
1615 depends on MEMORY_HOTPLUG
1617 config HAVE_ARCH_EARLY_PFN_TO_NID
1621 menu "Power management and ACPI options"
1623 config ARCH_HIBERNATION_HEADER
1625 depends on X86_64 && HIBERNATION
1627 source "kernel/power/Kconfig"
1629 source "drivers/acpi/Kconfig"
1634 depends on APM || APM_MODULE
1637 tristate "APM (Advanced Power Management) BIOS support"
1638 depends on X86_32 && PM_SLEEP
1640 APM is a BIOS specification for saving power using several different
1641 techniques. This is mostly useful for battery powered laptops with
1642 APM compliant BIOSes. If you say Y here, the system time will be
1643 reset after a RESUME operation, the /proc/apm device will provide
1644 battery status information, and user-space programs will receive
1645 notification of APM "events" (e.g. battery status change).
1647 If you select "Y" here, you can disable actual use of the APM
1648 BIOS by passing the "apm=off" option to the kernel at boot time.
1650 Note that the APM support is almost completely disabled for
1651 machines with more than one CPU.
1653 In order to use APM, you will need supporting software. For location
1654 and more information, read <file:Documentation/power/pm.txt> and the
1655 Battery Powered Linux mini-HOWTO, available from
1656 <http://www.tldp.org/docs.html#howto>.
1658 This driver does not spin down disk drives (see the hdparm(8)
1659 manpage ("man 8 hdparm") for that), and it doesn't turn off
1660 VESA-compliant "green" monitors.
1662 This driver does not support the TI 4000M TravelMate and the ACER
1663 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1664 desktop machines also don't have compliant BIOSes, and this driver
1665 may cause those machines to panic during the boot phase.
1667 Generally, if you don't have a battery in your machine, there isn't
1668 much point in using this driver and you should say N. If you get
1669 random kernel OOPSes or reboots that don't seem to be related to
1670 anything, try disabling/enabling this option (or disabling/enabling
1673 Some other things you should try when experiencing seemingly random,
1676 1) make sure that you have enough swap space and that it is
1678 2) pass the "no-hlt" option to the kernel
1679 3) switch on floating point emulation in the kernel and pass
1680 the "no387" option to the kernel
1681 4) pass the "floppy=nodma" option to the kernel
1682 5) pass the "mem=4M" option to the kernel (thereby disabling
1683 all but the first 4 MB of RAM)
1684 6) make sure that the CPU is not over clocked.
1685 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1686 8) disable the cache from your BIOS settings
1687 9) install a fan for the video card or exchange video RAM
1688 10) install a better fan for the CPU
1689 11) exchange RAM chips
1690 12) exchange the motherboard.
1692 To compile this driver as a module, choose M here: the
1693 module will be called apm.
1697 config APM_IGNORE_USER_SUSPEND
1698 bool "Ignore USER SUSPEND"
1700 This option will ignore USER SUSPEND requests. On machines with a
1701 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1702 series notebooks, it is necessary to say Y because of a BIOS bug.
1704 config APM_DO_ENABLE
1705 bool "Enable PM at boot time"
1707 Enable APM features at boot time. From page 36 of the APM BIOS
1708 specification: "When disabled, the APM BIOS does not automatically
1709 power manage devices, enter the Standby State, enter the Suspend
1710 State, or take power saving steps in response to CPU Idle calls."
1711 This driver will make CPU Idle calls when Linux is idle (unless this
1712 feature is turned off -- see "Do CPU IDLE calls", below). This
1713 should always save battery power, but more complicated APM features
1714 will be dependent on your BIOS implementation. You may need to turn
1715 this option off if your computer hangs at boot time when using APM
1716 support, or if it beeps continuously instead of suspending. Turn
1717 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1718 T400CDT. This is off by default since most machines do fine without
1722 bool "Make CPU Idle calls when idle"
1724 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1725 On some machines, this can activate improved power savings, such as
1726 a slowed CPU clock rate, when the machine is idle. These idle calls
1727 are made after the idle loop has run for some length of time (e.g.,
1728 333 mS). On some machines, this will cause a hang at boot time or
1729 whenever the CPU becomes idle. (On machines with more than one CPU,
1730 this option does nothing.)
1732 config APM_DISPLAY_BLANK
1733 bool "Enable console blanking using APM"
1735 Enable console blanking using the APM. Some laptops can use this to
1736 turn off the LCD backlight when the screen blanker of the Linux
1737 virtual console blanks the screen. Note that this is only used by
1738 the virtual console screen blanker, and won't turn off the backlight
1739 when using the X Window system. This also doesn't have anything to
1740 do with your VESA-compliant power-saving monitor. Further, this
1741 option doesn't work for all laptops -- it might not turn off your
1742 backlight at all, or it might print a lot of errors to the console,
1743 especially if you are using gpm.
1745 config APM_ALLOW_INTS
1746 bool "Allow interrupts during APM BIOS calls"
1748 Normally we disable external interrupts while we are making calls to
1749 the APM BIOS as a measure to lessen the effects of a badly behaving
1750 BIOS implementation. The BIOS should reenable interrupts if it
1751 needs to. Unfortunately, some BIOSes do not -- especially those in
1752 many of the newer IBM Thinkpads. If you experience hangs when you
1753 suspend, try setting this to Y. Otherwise, say N.
1757 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1759 source "drivers/cpuidle/Kconfig"
1761 source "drivers/idle/Kconfig"
1766 menu "Bus options (PCI etc.)"
1771 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1773 Find out whether you have a PCI motherboard. PCI is the name of a
1774 bus system, i.e. the way the CPU talks to the other stuff inside
1775 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1776 VESA. If you have PCI, say Y, otherwise N.
1779 prompt "PCI access mode"
1780 depends on X86_32 && PCI
1783 On PCI systems, the BIOS can be used to detect the PCI devices and
1784 determine their configuration. However, some old PCI motherboards
1785 have BIOS bugs and may crash if this is done. Also, some embedded
1786 PCI-based systems don't have any BIOS at all. Linux can also try to
1787 detect the PCI hardware directly without using the BIOS.
1789 With this option, you can specify how Linux should detect the
1790 PCI devices. If you choose "BIOS", the BIOS will be used,
1791 if you choose "Direct", the BIOS won't be used, and if you
1792 choose "MMConfig", then PCI Express MMCONFIG will be used.
1793 If you choose "Any", the kernel will try MMCONFIG, then the
1794 direct access method and falls back to the BIOS if that doesn't
1795 work. If unsure, go with the default, which is "Any".
1800 config PCI_GOMMCONFIG
1817 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1819 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1822 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1826 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1830 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1837 bool "Support mmconfig PCI config space access"
1838 depends on X86_64 && PCI && ACPI
1841 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1842 depends on PCI_MSI && ACPI && EXPERIMENTAL
1844 DMA remapping (DMAR) devices support enables independent address
1845 translations for Direct Memory Access (DMA) from devices.
1846 These DMA remapping devices are reported via ACPI tables
1847 and include PCI device scope covered by these DMA
1850 config DMAR_DEFAULT_ON
1852 prompt "Enable DMA Remapping Devices by default"
1855 Selecting this option will enable a DMAR device at boot time if
1856 one is found. If this option is not selected, DMAR support can
1857 be enabled by passing intel_iommu=on to the kernel. It is
1858 recommended you say N here while the DMAR code remains
1863 prompt "Support for Graphics workaround"
1866 Current Graphics drivers tend to use physical address
1867 for DMA and avoid using DMA APIs. Setting this config
1868 option permits the IOMMU driver to set a unity map for
1869 all the OS-visible memory. Hence the driver can continue
1870 to use physical addresses for DMA.
1872 config DMAR_FLOPPY_WA
1876 Floppy disk drivers are know to bypass DMA API calls
1877 thereby failing to work when IOMMU is enabled. This
1878 workaround will setup a 1:1 mapping for the first
1879 16M to make floppy (an ISA device) work.
1882 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1883 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1885 Supports Interrupt remapping for IO-APIC and MSI devices.
1886 To use x2apic mode in the CPU's which support x2APIC enhancements or
1887 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1889 source "drivers/pci/pcie/Kconfig"
1891 source "drivers/pci/Kconfig"
1893 # x86_64 have no ISA slots, but do have ISA-style DMA.
1902 Find out whether you have ISA slots on your motherboard. ISA is the
1903 name of a bus system, i.e. the way the CPU talks to the other stuff
1904 inside your box. Other bus systems are PCI, EISA, MicroChannel
1905 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1906 newer boards don't support it. If you have ISA, say Y, otherwise N.
1912 The Extended Industry Standard Architecture (EISA) bus was
1913 developed as an open alternative to the IBM MicroChannel bus.
1915 The EISA bus provided some of the features of the IBM MicroChannel
1916 bus while maintaining backward compatibility with cards made for
1917 the older ISA bus. The EISA bus saw limited use between 1988 and
1918 1995 when it was made obsolete by the PCI bus.
1920 Say Y here if you are building a kernel for an EISA-based machine.
1924 source "drivers/eisa/Kconfig"
1929 MicroChannel Architecture is found in some IBM PS/2 machines and
1930 laptops. It is a bus system similar to PCI or ISA. See
1931 <file:Documentation/mca.txt> (and especially the web page given
1932 there) before attempting to build an MCA bus kernel.
1934 source "drivers/mca/Kconfig"
1937 tristate "NatSemi SCx200 support"
1939 This provides basic support for National Semiconductor's
1940 (now AMD's) Geode processors. The driver probes for the
1941 PCI-IDs of several on-chip devices, so its a good dependency
1942 for other scx200_* drivers.
1944 If compiled as a module, the driver is named scx200.
1946 config SCx200HR_TIMER
1947 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1948 depends on SCx200 && GENERIC_TIME
1951 This driver provides a clocksource built upon the on-chip
1952 27MHz high-resolution timer. Its also a workaround for
1953 NSC Geode SC-1100's buggy TSC, which loses time when the
1954 processor goes idle (as is done by the scheduler). The
1955 other workaround is idle=poll boot option.
1957 config GEODE_MFGPT_TIMER
1959 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1960 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1962 This driver provides a clock event source based on the MFGPT
1963 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1964 MFGPTs have a better resolution and max interval than the
1965 generic PIT, and are suitable for use as high-res timers.
1968 bool "One Laptop Per Child support"
1971 Add support for detecting the unique features of the OLPC
1978 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1980 source "drivers/pcmcia/Kconfig"
1982 source "drivers/pci/hotplug/Kconfig"
1987 menu "Executable file formats / Emulations"
1989 source "fs/Kconfig.binfmt"
1991 config IA32_EMULATION
1992 bool "IA32 Emulation"
1994 select COMPAT_BINFMT_ELF
1996 Include code to run 32-bit programs under a 64-bit kernel. You should
1997 likely turn this on, unless you're 100% sure that you don't have any
1998 32-bit programs left.
2001 tristate "IA32 a.out support"
2002 depends on IA32_EMULATION
2004 Support old a.out binaries in the 32bit emulation.
2008 depends on IA32_EMULATION
2010 config COMPAT_FOR_U64_ALIGNMENT
2014 config SYSVIPC_COMPAT
2016 depends on COMPAT && SYSVIPC
2021 config HAVE_ATOMIC_IOMAP
2025 source "net/Kconfig"
2027 source "drivers/Kconfig"
2029 source "drivers/firmware/Kconfig"
2033 source "arch/x86/Kconfig.debug"
2035 source "security/Kconfig"
2037 source "crypto/Kconfig"
2039 source "arch/x86/kvm/Kconfig"
2041 source "lib/Kconfig"
projects / linux-2.6 / blob