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.
279 depends on SPARSE_IRQ && NUMA
282 bool "Enable MPS table" if ACPI
284 depends on X86_LOCAL_APIC
286 For old smp systems that do not have proper acpi support. Newer systems
287 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
290 bool "Support for big SMP systems with more than 8 CPUs"
291 depends on X86_32 && SMP
293 This option is needed for the systems that have more than 8 CPUs
296 config X86_EXTENDED_PLATFORM
297 bool "Support for extended (non-PC) x86 platforms"
300 If you disable this option then the kernel will only support
301 standard PC platforms. (which covers the vast majority of
304 If you enable this option then you'll be able to select support
305 for the following (non-PC) 32 bit x86 platforms:
309 SGI 320/540 (Visual Workstation)
310 Summit/EXA (IBM x440)
311 Unisys ES7000 IA32 series
313 If you have one of these systems, or if you want to build a
314 generic distribution kernel, say Y here - otherwise say N.
318 config X86_EXTENDED_PLATFORM
319 bool "Support for extended (non-PC) x86 platforms"
322 If you disable this option then the kernel will only support
323 standard PC platforms. (which covers the vast majority of
326 If you enable this option then you'll be able to select support
327 for the following (non-PC) 64 bit x86 platforms:
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
334 # This is an alphabetically sorted list of 64 bit extended platforms
335 # Please maintain the alphabetic order if and when there are additions
340 depends on X86_64 && PCI
341 depends on X86_EXTENDED_PLATFORM
343 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
344 supposed to run on these EM64T-based machines. Only choose this option
345 if you have one of these machines.
348 bool "SGI Ultraviolet"
350 depends on X86_EXTENDED_PLATFORM
352 depends on X86_X2APIC
354 This option is needed in order to support SGI Ultraviolet systems.
355 If you don't have one of these, you should say N here.
357 # Following is an alphabetically sorted list of 32 bit extended platforms
358 # Please maintain the alphabetic order if and when there are additions
363 depends on X86_EXTENDED_PLATFORM
365 Select this for an AMD Elan processor.
367 Do not use this option for K6/Athlon/Opteron processors!
369 If unsure, choose "PC-compatible" instead.
372 bool "RDC R-321x SoC"
374 depends on X86_EXTENDED_PLATFORM
376 select X86_REBOOTFIXUPS
378 This option is needed for RDC R-321x system-on-chip, also known
380 If you don't have one of these chips, you should say N here.
382 config X86_32_NON_STANDARD
383 bool "Support non-standard 32-bit SMP architectures"
384 depends on X86_32 && SMP
385 depends on X86_EXTENDED_PLATFORM
387 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
388 subarchitectures. It is intended for a generic binary kernel.
389 if you select them all, kernel will probe it one by one. and will
392 # Alphabetically sorted list of Non standard 32 bit platforms
395 bool "NUMAQ (IBM/Sequent)"
396 depends on X86_32_NON_STANDARD
400 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
401 NUMA multiquad box. This changes the way that processors are
402 bootstrapped, and uses Clustered Logical APIC addressing mode instead
403 of Flat Logical. You will need a new lynxer.elf file to flash your
404 firmware with - send email to <Martin.Bligh@us.ibm.com>.
407 bool "SGI 320/540 (Visual Workstation)"
408 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
409 depends on X86_32_NON_STANDARD
411 The SGI Visual Workstation series is an IA32-based workstation
412 based on SGI systems chips with some legacy PC hardware attached.
414 Say Y here to create a kernel to run on the SGI 320 or 540.
416 A kernel compiled for the Visual Workstation will run on general
417 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
420 bool "Summit/EXA (IBM x440)"
421 depends on X86_32_NON_STANDARD
423 This option is needed for IBM systems that use the Summit/EXA chipset.
424 In particular, it is needed for the x440.
427 bool "Unisys ES7000 IA32 series"
428 depends on X86_32_NON_STANDARD && X86_BIGSMP
430 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
431 supposed to run on an IA32-based Unisys ES7000 system.
433 config SCHED_OMIT_FRAME_POINTER
435 prompt "Single-depth WCHAN output"
438 Calculate simpler /proc/<PID>/wchan values. If this option
439 is disabled then wchan values will recurse back to the
440 caller function. This provides more accurate wchan values,
441 at the expense of slightly more scheduling overhead.
443 If in doubt, say "Y".
445 menuconfig PARAVIRT_GUEST
446 bool "Paravirtualized guest support"
448 Say Y here to get to see options related to running Linux under
449 various hypervisors. This option alone does not add any kernel code.
451 If you say N, all options in this submenu will be skipped and disabled.
455 source "arch/x86/xen/Kconfig"
458 bool "VMI Guest support"
462 VMI provides a paravirtualized interface to the VMware ESX server
463 (it could be used by other hypervisors in theory too, but is not
464 at the moment), by linking the kernel to a GPL-ed ROM module
465 provided by the hypervisor.
468 bool "KVM paravirtualized clock"
470 select PARAVIRT_CLOCK
472 Turning on this option will allow you to run a paravirtualized clock
473 when running over the KVM hypervisor. Instead of relying on a PIT
474 (or probably other) emulation by the underlying device model, the host
475 provides the guest with timing infrastructure such as time of day, and
479 bool "KVM Guest support"
482 This option enables various optimizations for running under the KVM
485 source "arch/x86/lguest/Kconfig"
488 bool "Enable paravirtualization code"
490 This changes the kernel so it can modify itself when it is run
491 under a hypervisor, potentially improving performance significantly
492 over full virtualization. However, when run without a hypervisor
493 the kernel is theoretically slower and slightly larger.
495 config PARAVIRT_CLOCK
501 config PARAVIRT_DEBUG
502 bool "paravirt-ops debugging"
503 depends on PARAVIRT && DEBUG_KERNEL
505 Enable to debug paravirt_ops internals. Specifically, BUG if
506 a paravirt_op is missing when it is called.
511 This option adds a kernel parameter 'memtest', which allows memtest
513 memtest=0, mean disabled; -- default
514 memtest=1, mean do 1 test pattern;
516 memtest=4, mean do 4 test patterns.
517 If you are unsure how to answer this question, answer N.
519 config X86_SUMMIT_NUMA
521 depends on X86_32 && NUMA && X86_32_NON_STANDARD
523 config X86_CYCLONE_TIMER
525 depends on X86_32_NON_STANDARD
527 source "arch/x86/Kconfig.cpu"
531 prompt "HPET Timer Support" if X86_32
533 Use the IA-PC HPET (High Precision Event Timer) to manage
534 time in preference to the PIT and RTC, if a HPET is
536 HPET is the next generation timer replacing legacy 8254s.
537 The HPET provides a stable time base on SMP
538 systems, unlike the TSC, but it is more expensive to access,
539 as it is off-chip. You can find the HPET spec at
540 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
542 You can safely choose Y here. However, HPET will only be
543 activated if the platform and the BIOS support this feature.
544 Otherwise the 8254 will be used for timing services.
546 Choose N to continue using the legacy 8254 timer.
548 config HPET_EMULATE_RTC
550 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
552 # Mark as embedded because too many people got it wrong.
553 # The code disables itself when not needed.
556 bool "Enable DMI scanning" if EMBEDDED
558 Enabled scanning of DMI to identify machine quirks. Say Y
559 here unless you have verified that your setup is not
560 affected by entries in the DMI blacklist. Required by PNP
564 bool "GART IOMMU support" if EMBEDDED
568 depends on X86_64 && PCI
570 Support for full DMA access of devices with 32bit memory access only
571 on systems with more than 3GB. This is usually needed for USB,
572 sound, many IDE/SATA chipsets and some other devices.
573 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
574 based hardware IOMMU and a software bounce buffer based IOMMU used
575 on Intel systems and as fallback.
576 The code is only active when needed (enough memory and limited
577 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
581 bool "IBM Calgary IOMMU support"
583 depends on X86_64 && PCI && EXPERIMENTAL
585 Support for hardware IOMMUs in IBM's xSeries x366 and x460
586 systems. Needed to run systems with more than 3GB of memory
587 properly with 32-bit PCI devices that do not support DAC
588 (Double Address Cycle). Calgary also supports bus level
589 isolation, where all DMAs pass through the IOMMU. This
590 prevents them from going anywhere except their intended
591 destination. This catches hard-to-find kernel bugs and
592 mis-behaving drivers and devices that do not use the DMA-API
593 properly to set up their DMA buffers. The IOMMU can be
594 turned off at boot time with the iommu=off parameter.
595 Normally the kernel will make the right choice by itself.
598 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
600 prompt "Should Calgary be enabled by default?"
601 depends on CALGARY_IOMMU
603 Should Calgary be enabled by default? if you choose 'y', Calgary
604 will be used (if it exists). If you choose 'n', Calgary will not be
605 used even if it exists. If you choose 'n' and would like to use
606 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
610 bool "AMD IOMMU support"
613 depends on X86_64 && PCI && ACPI
615 With this option you can enable support for AMD IOMMU hardware in
616 your system. An IOMMU is a hardware component which provides
617 remapping of DMA memory accesses from devices. With an AMD IOMMU you
618 can isolate the the DMA memory of different devices and protect the
619 system from misbehaving device drivers or hardware.
621 You can find out if your system has an AMD IOMMU if you look into
622 your BIOS for an option to enable it or if you have an IVRS ACPI
625 config AMD_IOMMU_STATS
626 bool "Export AMD IOMMU statistics to debugfs"
630 This option enables code in the AMD IOMMU driver to collect various
631 statistics about whats happening in the driver and exports that
632 information to userspace via debugfs.
635 # need this always selected by IOMMU for the VIA workaround
639 Support for software bounce buffers used on x86-64 systems
640 which don't have a hardware IOMMU (e.g. the current generation
641 of Intel's x86-64 CPUs). Using this PCI devices which can only
642 access 32-bits of memory can be used on systems with more than
643 3 GB of memory. If unsure, say Y.
646 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
649 def_bool (AMD_IOMMU || DMAR)
652 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
653 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
654 select CPUMASK_OFFSTACK
657 Configure maximum number of CPUS and NUMA Nodes for this architecture.
661 int "Maximum number of CPUs" if SMP && !MAXSMP
662 range 2 8 if SMP && X86_32 && !X86_BIGSMP
663 range 2 512 if SMP && !MAXSMP
665 default "4096" if MAXSMP
666 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
669 This allows you to specify the maximum number of CPUs which this
670 kernel will support. The maximum supported value is 512 and the
671 minimum value which makes sense is 2.
673 This is purely to save memory - each supported CPU adds
674 approximately eight kilobytes to the kernel image.
677 bool "SMT (Hyperthreading) scheduler support"
680 SMT scheduler support improves the CPU scheduler's decision making
681 when dealing with Intel Pentium 4 chips with HyperThreading at a
682 cost of slightly increased overhead in some places. If unsure say
687 prompt "Multi-core scheduler support"
690 Multi-core scheduler support improves the CPU scheduler's decision
691 making when dealing with multi-core CPU chips at a cost of slightly
692 increased overhead in some places. If unsure say N here.
694 source "kernel/Kconfig.preempt"
697 bool "Local APIC support on uniprocessors"
698 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
700 A local APIC (Advanced Programmable Interrupt Controller) is an
701 integrated interrupt controller in the CPU. If you have a single-CPU
702 system which has a processor with a local APIC, you can say Y here to
703 enable and use it. If you say Y here even though your machine doesn't
704 have a local APIC, then the kernel will still run with no slowdown at
705 all. The local APIC supports CPU-generated self-interrupts (timer,
706 performance counters), and the NMI watchdog which detects hard
710 bool "IO-APIC support on uniprocessors"
711 depends on X86_UP_APIC
713 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
714 SMP-capable replacement for PC-style interrupt controllers. Most
715 SMP systems and many recent uniprocessor systems have one.
717 If you have a single-CPU system with an IO-APIC, you can say Y here
718 to use it. If you say Y here even though your machine doesn't have
719 an IO-APIC, then the kernel will still run with no slowdown at all.
721 config X86_LOCAL_APIC
723 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
727 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
729 config X86_VISWS_APIC
731 depends on X86_32 && X86_VISWS
733 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
734 bool "Reroute for broken boot IRQs"
736 depends on X86_IO_APIC
738 This option enables a workaround that fixes a source of
739 spurious interrupts. This is recommended when threaded
740 interrupt handling is used on systems where the generation of
741 superfluous "boot interrupts" cannot be disabled.
743 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
744 entry in the chipset's IO-APIC is masked (as, e.g. the RT
745 kernel does during interrupt handling). On chipsets where this
746 boot IRQ generation cannot be disabled, this workaround keeps
747 the original IRQ line masked so that only the equivalent "boot
748 IRQ" is delivered to the CPUs. The workaround also tells the
749 kernel to set up the IRQ handler on the boot IRQ line. In this
750 way only one interrupt is delivered to the kernel. Otherwise
751 the spurious second interrupt may cause the kernel to bring
752 down (vital) interrupt lines.
754 Only affects "broken" chipsets. Interrupt sharing may be
755 increased on these systems.
758 bool "Machine Check Exception"
760 Machine Check Exception support allows the processor to notify the
761 kernel if it detects a problem (e.g. overheating, component failure).
762 The action the kernel takes depends on the severity of the problem,
763 ranging from a warning message on the console, to halting the machine.
764 Your processor must be a Pentium or newer to support this - check the
765 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
766 have a design flaw which leads to false MCE events - hence MCE is
767 disabled on all P5 processors, unless explicitly enabled with "mce"
768 as a boot argument. Similarly, if MCE is built in and creates a
769 problem on some new non-standard machine, you can boot with "nomce"
770 to disable it. MCE support simply ignores non-MCE processors like
771 the 386 and 486, so nearly everyone can say Y here.
775 prompt "Intel MCE features"
776 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
778 Additional support for intel specific MCE features such as
783 prompt "AMD MCE features"
784 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
786 Additional support for AMD specific MCE features such as
787 the DRAM Error Threshold.
789 config X86_MCE_THRESHOLD
790 depends on X86_MCE_AMD || X86_MCE_INTEL
794 config X86_MCE_NONFATAL
795 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
796 depends on X86_32 && X86_MCE
798 Enabling this feature starts a timer that triggers every 5 seconds which
799 will look at the machine check registers to see if anything happened.
800 Non-fatal problems automatically get corrected (but still logged).
801 Disable this if you don't want to see these messages.
802 Seeing the messages this option prints out may be indicative of dying
803 or out-of-spec (ie, overclocked) hardware.
804 This option only does something on certain CPUs.
805 (AMD Athlon/Duron and Intel Pentium 4)
807 config X86_MCE_P4THERMAL
808 bool "check for P4 thermal throttling interrupt."
809 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
811 Enabling this feature will cause a message to be printed when the P4
812 enters thermal throttling.
815 bool "Enable VM86 support" if EMBEDDED
819 This option is required by programs like DOSEMU to run 16-bit legacy
820 code on X86 processors. It also may be needed by software like
821 XFree86 to initialize some video cards via BIOS. Disabling this
822 option saves about 6k.
825 tristate "Toshiba Laptop support"
828 This adds a driver to safely access the System Management Mode of
829 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
830 not work on models with a Phoenix BIOS. The System Management Mode
831 is used to set the BIOS and power saving options on Toshiba portables.
833 For information on utilities to make use of this driver see the
834 Toshiba Linux utilities web site at:
835 <http://www.buzzard.org.uk/toshiba/>.
837 Say Y if you intend to run this kernel on a Toshiba portable.
841 tristate "Dell laptop support"
843 This adds a driver to safely access the System Management Mode
844 of the CPU on the Dell Inspiron 8000. The System Management Mode
845 is used to read cpu temperature and cooling fan status and to
846 control the fans on the I8K portables.
848 This driver has been tested only on the Inspiron 8000 but it may
849 also work with other Dell laptops. You can force loading on other
850 models by passing the parameter `force=1' to the module. Use at
853 For information on utilities to make use of this driver see the
854 I8K Linux utilities web site at:
855 <http://people.debian.org/~dz/i8k/>
857 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
860 config X86_REBOOTFIXUPS
861 bool "Enable X86 board specific fixups for reboot"
864 This enables chipset and/or board specific fixups to be done
865 in order to get reboot to work correctly. This is only needed on
866 some combinations of hardware and BIOS. The symptom, for which
867 this config is intended, is when reboot ends with a stalled/hung
870 Currently, the only fixup is for the Geode machines using
871 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
873 Say Y if you want to enable the fixup. Currently, it's safe to
874 enable this option even if you don't need it.
878 tristate "/dev/cpu/microcode - microcode support"
881 If you say Y here, you will be able to update the microcode on
882 certain Intel and AMD processors. The Intel support is for the
883 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
884 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
885 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
886 You will obviously need the actual microcode binary data itself
887 which is not shipped with the Linux kernel.
889 This option selects the general module only, you need to select
890 at least one vendor specific module as well.
892 To compile this driver as a module, choose M here: the
893 module will be called microcode.
895 config MICROCODE_INTEL
896 bool "Intel microcode patch loading support"
901 This options enables microcode patch loading support for Intel
904 For latest news and information on obtaining all the required
905 Intel ingredients for this driver, check:
906 <http://www.urbanmyth.org/microcode/>.
909 bool "AMD microcode patch loading support"
913 If you select this option, microcode patch loading support for AMD
914 processors will be enabled.
916 config MICROCODE_OLD_INTERFACE
921 tristate "/dev/cpu/*/msr - Model-specific register support"
923 This device gives privileged processes access to the x86
924 Model-Specific Registers (MSRs). It is a character device with
925 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
926 MSR accesses are directed to a specific CPU on multi-processor
930 tristate "/dev/cpu/*/cpuid - CPU information support"
932 This device gives processes access to the x86 CPUID instruction to
933 be executed on a specific processor. It is a character device
934 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
938 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
940 If you select this option, this will provide various x86 CPUs
941 information through debugfs.
944 prompt "High Memory Support"
945 default HIGHMEM4G if !X86_NUMAQ
946 default HIGHMEM64G if X86_NUMAQ
951 depends on !X86_NUMAQ
953 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
954 However, the address space of 32-bit x86 processors is only 4
955 Gigabytes large. That means that, if you have a large amount of
956 physical memory, not all of it can be "permanently mapped" by the
957 kernel. The physical memory that's not permanently mapped is called
960 If you are compiling a kernel which will never run on a machine with
961 more than 1 Gigabyte total physical RAM, answer "off" here (default
962 choice and suitable for most users). This will result in a "3GB/1GB"
963 split: 3GB are mapped so that each process sees a 3GB virtual memory
964 space and the remaining part of the 4GB virtual memory space is used
965 by the kernel to permanently map as much physical memory as
968 If the machine has between 1 and 4 Gigabytes physical RAM, then
971 If more than 4 Gigabytes is used then answer "64GB" here. This
972 selection turns Intel PAE (Physical Address Extension) mode on.
973 PAE implements 3-level paging on IA32 processors. PAE is fully
974 supported by Linux, PAE mode is implemented on all recent Intel
975 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
976 then the kernel will not boot on CPUs that don't support PAE!
978 The actual amount of total physical memory will either be
979 auto detected or can be forced by using a kernel command line option
980 such as "mem=256M". (Try "man bootparam" or see the documentation of
981 your boot loader (lilo or loadlin) about how to pass options to the
982 kernel at boot time.)
984 If unsure, say "off".
988 depends on !X86_NUMAQ
990 Select this if you have a 32-bit processor and between 1 and 4
991 gigabytes of physical RAM.
995 depends on !M386 && !M486
998 Select this if you have a 32-bit processor and more than 4
999 gigabytes of physical RAM.
1004 depends on EXPERIMENTAL
1005 prompt "Memory split" if EMBEDDED
1009 Select the desired split between kernel and user memory.
1011 If the address range available to the kernel is less than the
1012 physical memory installed, the remaining memory will be available
1013 as "high memory". Accessing high memory is a little more costly
1014 than low memory, as it needs to be mapped into the kernel first.
1015 Note that increasing the kernel address space limits the range
1016 available to user programs, making the address space there
1017 tighter. Selecting anything other than the default 3G/1G split
1018 will also likely make your kernel incompatible with binary-only
1021 If you are not absolutely sure what you are doing, leave this
1025 bool "3G/1G user/kernel split"
1026 config VMSPLIT_3G_OPT
1028 bool "3G/1G user/kernel split (for full 1G low memory)"
1030 bool "2G/2G user/kernel split"
1031 config VMSPLIT_2G_OPT
1033 bool "2G/2G user/kernel split (for full 2G low memory)"
1035 bool "1G/3G user/kernel split"
1040 default 0xB0000000 if VMSPLIT_3G_OPT
1041 default 0x80000000 if VMSPLIT_2G
1042 default 0x78000000 if VMSPLIT_2G_OPT
1043 default 0x40000000 if VMSPLIT_1G
1049 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1052 bool "PAE (Physical Address Extension) Support"
1053 depends on X86_32 && !HIGHMEM4G
1055 PAE is required for NX support, and furthermore enables
1056 larger swapspace support for non-overcommit purposes. It
1057 has the cost of more pagetable lookup overhead, and also
1058 consumes more pagetable space per process.
1060 config ARCH_PHYS_ADDR_T_64BIT
1061 def_bool X86_64 || X86_PAE
1063 config DIRECT_GBPAGES
1064 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1068 Allow the kernel linear mapping to use 1GB pages on CPUs that
1069 support it. This can improve the kernel's performance a tiny bit by
1070 reducing TLB pressure. If in doubt, say "Y".
1072 # Common NUMA Features
1074 bool "Numa Memory Allocation and Scheduler Support"
1076 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1077 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1079 Enable NUMA (Non Uniform Memory Access) support.
1081 The kernel will try to allocate memory used by a CPU on the
1082 local memory controller of the CPU and add some more
1083 NUMA awareness to the kernel.
1085 For 64-bit this is recommended if the system is Intel Core i7
1086 (or later), AMD Opteron, or EM64T NUMA.
1088 For 32-bit this is only needed on (rare) 32-bit-only platforms
1089 that support NUMA topologies, such as NUMAQ / Summit, or if you
1090 boot a 32-bit kernel on a 64-bit NUMA platform.
1092 Otherwise, you should say N.
1094 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1095 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1099 prompt "Old style AMD Opteron NUMA detection"
1100 depends on X86_64 && NUMA && PCI
1102 Enable K8 NUMA node topology detection. You should say Y here if
1103 you have a multi processor AMD K8 system. This uses an old
1104 method to read the NUMA configuration directly from the builtin
1105 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1106 instead, which also takes priority if both are compiled in.
1108 config X86_64_ACPI_NUMA
1110 prompt "ACPI NUMA detection"
1111 depends on X86_64 && NUMA && ACPI && PCI
1114 Enable ACPI SRAT based node topology detection.
1116 # Some NUMA nodes have memory ranges that span
1117 # other nodes. Even though a pfn is valid and
1118 # between a node's start and end pfns, it may not
1119 # reside on that node. See memmap_init_zone()
1121 config NODES_SPAN_OTHER_NODES
1123 depends on X86_64_ACPI_NUMA
1126 bool "NUMA emulation"
1127 depends on X86_64 && NUMA
1129 Enable NUMA emulation. A flat machine will be split
1130 into virtual nodes when booted with "numa=fake=N", where N is the
1131 number of nodes. This is only useful for debugging.
1134 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1136 default "9" if MAXSMP
1137 default "6" if X86_64
1138 default "4" if X86_NUMAQ
1140 depends on NEED_MULTIPLE_NODES
1142 Specify the maximum number of NUMA Nodes available on the target
1143 system. Increases memory reserved to accommodate various tables.
1145 config HAVE_ARCH_BOOTMEM
1147 depends on X86_32 && NUMA
1149 config ARCH_HAVE_MEMORY_PRESENT
1151 depends on X86_32 && DISCONTIGMEM
1153 config NEED_NODE_MEMMAP_SIZE
1155 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1157 config HAVE_ARCH_ALLOC_REMAP
1159 depends on X86_32 && NUMA
1161 config ARCH_FLATMEM_ENABLE
1163 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1165 config ARCH_DISCONTIGMEM_ENABLE
1167 depends on NUMA && X86_32
1169 config ARCH_DISCONTIGMEM_DEFAULT
1171 depends on NUMA && X86_32
1173 config ARCH_SPARSEMEM_DEFAULT
1177 config ARCH_SPARSEMEM_ENABLE
1179 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1180 select SPARSEMEM_STATIC if X86_32
1181 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1183 config ARCH_SELECT_MEMORY_MODEL
1185 depends on ARCH_SPARSEMEM_ENABLE
1187 config ARCH_MEMORY_PROBE
1189 depends on MEMORY_HOTPLUG
1194 bool "Allocate 3rd-level pagetables from highmem"
1195 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1197 The VM uses one page table entry for each page of physical memory.
1198 For systems with a lot of RAM, this can be wasteful of precious
1199 low memory. Setting this option will put user-space page table
1200 entries in high memory.
1202 config X86_CHECK_BIOS_CORRUPTION
1203 bool "Check for low memory corruption"
1205 Periodically check for memory corruption in low memory, which
1206 is suspected to be caused by BIOS. Even when enabled in the
1207 configuration, it is disabled at runtime. Enable it by
1208 setting "memory_corruption_check=1" on the kernel command
1209 line. By default it scans the low 64k of memory every 60
1210 seconds; see the memory_corruption_check_size and
1211 memory_corruption_check_period parameters in
1212 Documentation/kernel-parameters.txt to adjust this.
1214 When enabled with the default parameters, this option has
1215 almost no overhead, as it reserves a relatively small amount
1216 of memory and scans it infrequently. It both detects corruption
1217 and prevents it from affecting the running system.
1219 It is, however, intended as a diagnostic tool; if repeatable
1220 BIOS-originated corruption always affects the same memory,
1221 you can use memmap= to prevent the kernel from using that
1224 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1225 bool "Set the default setting of memory_corruption_check"
1226 depends on X86_CHECK_BIOS_CORRUPTION
1229 Set whether the default state of memory_corruption_check is
1232 config X86_RESERVE_LOW_64K
1233 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1236 Reserve the first 64K of physical RAM on BIOSes that are known
1237 to potentially corrupt that memory range. A numbers of BIOSes are
1238 known to utilize this area during suspend/resume, so it must not
1239 be used by the kernel.
1241 Set this to N if you are absolutely sure that you trust the BIOS
1242 to get all its memory reservations and usages right.
1244 If you have doubts about the BIOS (e.g. suspend/resume does not
1245 work or there's kernel crashes after certain hardware hotplug
1246 events) and it's not AMI or Phoenix, then you might want to enable
1247 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1248 corruption patterns.
1252 config MATH_EMULATION
1254 prompt "Math emulation" if X86_32
1256 Linux can emulate a math coprocessor (used for floating point
1257 operations) if you don't have one. 486DX and Pentium processors have
1258 a math coprocessor built in, 486SX and 386 do not, unless you added
1259 a 487DX or 387, respectively. (The messages during boot time can
1260 give you some hints here ["man dmesg"].) Everyone needs either a
1261 coprocessor or this emulation.
1263 If you don't have a math coprocessor, you need to say Y here; if you
1264 say Y here even though you have a coprocessor, the coprocessor will
1265 be used nevertheless. (This behavior can be changed with the kernel
1266 command line option "no387", which comes handy if your coprocessor
1267 is broken. Try "man bootparam" or see the documentation of your boot
1268 loader (lilo or loadlin) about how to pass options to the kernel at
1269 boot time.) This means that it is a good idea to say Y here if you
1270 intend to use this kernel on different machines.
1272 More information about the internals of the Linux math coprocessor
1273 emulation can be found in <file:arch/x86/math-emu/README>.
1275 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1276 kernel, it won't hurt.
1279 bool "MTRR (Memory Type Range Register) support"
1281 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1282 the Memory Type Range Registers (MTRRs) may be used to control
1283 processor access to memory ranges. This is most useful if you have
1284 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1285 allows bus write transfers to be combined into a larger transfer
1286 before bursting over the PCI/AGP bus. This can increase performance
1287 of image write operations 2.5 times or more. Saying Y here creates a
1288 /proc/mtrr file which may be used to manipulate your processor's
1289 MTRRs. Typically the X server should use this.
1291 This code has a reasonably generic interface so that similar
1292 control registers on other processors can be easily supported
1295 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1296 Registers (ARRs) which provide a similar functionality to MTRRs. For
1297 these, the ARRs are used to emulate the MTRRs.
1298 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1299 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1300 write-combining. All of these processors are supported by this code
1301 and it makes sense to say Y here if you have one of them.
1303 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1304 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1305 can lead to all sorts of problems, so it's good to say Y here.
1307 You can safely say Y even if your machine doesn't have MTRRs, you'll
1308 just add about 9 KB to your kernel.
1310 See <file:Documentation/x86/mtrr.txt> for more information.
1312 config MTRR_SANITIZER
1314 prompt "MTRR cleanup support"
1317 Convert MTRR layout from continuous to discrete, so X drivers can
1318 add writeback entries.
1320 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1321 The largest mtrr entry size for a continuous block can be set with
1326 config MTRR_SANITIZER_ENABLE_DEFAULT
1327 int "MTRR cleanup enable value (0-1)"
1330 depends on MTRR_SANITIZER
1332 Enable mtrr cleanup default value
1334 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1335 int "MTRR cleanup spare reg num (0-7)"
1338 depends on MTRR_SANITIZER
1340 mtrr cleanup spare entries default, it can be changed via
1341 mtrr_spare_reg_nr=N on the kernel command line.
1345 prompt "x86 PAT support"
1348 Use PAT attributes to setup page level cache control.
1350 PATs are the modern equivalents of MTRRs and are much more
1351 flexible than MTRRs.
1353 Say N here if you see bootup problems (boot crash, boot hang,
1354 spontaneous reboots) or a non-working video driver.
1359 bool "EFI runtime service support"
1362 This enables the kernel to use EFI runtime services that are
1363 available (such as the EFI variable services).
1365 This option is only useful on systems that have EFI firmware.
1366 In addition, you should use the latest ELILO loader available
1367 at <http://elilo.sourceforge.net> in order to take advantage
1368 of EFI runtime services. However, even with this option, the
1369 resultant kernel should continue to boot on existing non-EFI
1374 prompt "Enable seccomp to safely compute untrusted bytecode"
1376 This kernel feature is useful for number crunching applications
1377 that may need to compute untrusted bytecode during their
1378 execution. By using pipes or other transports made available to
1379 the process as file descriptors supporting the read/write
1380 syscalls, it's possible to isolate those applications in
1381 their own address space using seccomp. Once seccomp is
1382 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1383 and the task is only allowed to execute a few safe syscalls
1384 defined by each seccomp mode.
1386 If unsure, say Y. Only embedded should say N here.
1388 config CC_STACKPROTECTOR_ALL
1391 config CC_STACKPROTECTOR
1392 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1393 select CC_STACKPROTECTOR_ALL
1395 This option turns on the -fstack-protector GCC feature. This
1396 feature puts, at the beginning of functions, a canary value on
1397 the stack just before the return address, and validates
1398 the value just before actually returning. Stack based buffer
1399 overflows (that need to overwrite this return address) now also
1400 overwrite the canary, which gets detected and the attack is then
1401 neutralized via a kernel panic.
1403 This feature requires gcc version 4.2 or above, or a distribution
1404 gcc with the feature backported. Older versions are automatically
1405 detected and for those versions, this configuration option is
1406 ignored. (and a warning is printed during bootup)
1408 source kernel/Kconfig.hz
1411 bool "kexec system call"
1413 kexec is a system call that implements the ability to shutdown your
1414 current kernel, and to start another kernel. It is like a reboot
1415 but it is independent of the system firmware. And like a reboot
1416 you can start any kernel with it, not just Linux.
1418 The name comes from the similarity to the exec system call.
1420 It is an ongoing process to be certain the hardware in a machine
1421 is properly shutdown, so do not be surprised if this code does not
1422 initially work for you. It may help to enable device hotplugging
1423 support. As of this writing the exact hardware interface is
1424 strongly in flux, so no good recommendation can be made.
1427 bool "kernel crash dumps"
1428 depends on X86_64 || (X86_32 && HIGHMEM)
1430 Generate crash dump after being started by kexec.
1431 This should be normally only set in special crash dump kernels
1432 which are loaded in the main kernel with kexec-tools into
1433 a specially reserved region and then later executed after
1434 a crash by kdump/kexec. The crash dump kernel must be compiled
1435 to a memory address not used by the main kernel or BIOS using
1436 PHYSICAL_START, or it must be built as a relocatable image
1437 (CONFIG_RELOCATABLE=y).
1438 For more details see Documentation/kdump/kdump.txt
1441 bool "kexec jump (EXPERIMENTAL)"
1442 depends on EXPERIMENTAL
1443 depends on KEXEC && HIBERNATION
1445 Jump between original kernel and kexeced kernel and invoke
1446 code in physical address mode via KEXEC
1448 config PHYSICAL_START
1449 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1450 default "0x1000000" if X86_NUMAQ
1451 default "0x200000" if X86_64
1454 This gives the physical address where the kernel is loaded.
1456 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1457 bzImage will decompress itself to above physical address and
1458 run from there. Otherwise, bzImage will run from the address where
1459 it has been loaded by the boot loader and will ignore above physical
1462 In normal kdump cases one does not have to set/change this option
1463 as now bzImage can be compiled as a completely relocatable image
1464 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1465 address. This option is mainly useful for the folks who don't want
1466 to use a bzImage for capturing the crash dump and want to use a
1467 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1468 to be specifically compiled to run from a specific memory area
1469 (normally a reserved region) and this option comes handy.
1471 So if you are using bzImage for capturing the crash dump, leave
1472 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1473 Otherwise if you plan to use vmlinux for capturing the crash dump
1474 change this value to start of the reserved region (Typically 16MB
1475 0x1000000). In other words, it can be set based on the "X" value as
1476 specified in the "crashkernel=YM@XM" command line boot parameter
1477 passed to the panic-ed kernel. Typically this parameter is set as
1478 crashkernel=64M@16M. Please take a look at
1479 Documentation/kdump/kdump.txt for more details about crash dumps.
1481 Usage of bzImage for capturing the crash dump is recommended as
1482 one does not have to build two kernels. Same kernel can be used
1483 as production kernel and capture kernel. Above option should have
1484 gone away after relocatable bzImage support is introduced. But it
1485 is present because there are users out there who continue to use
1486 vmlinux for dump capture. This option should go away down the
1489 Don't change this unless you know what you are doing.
1492 bool "Build a relocatable kernel (EXPERIMENTAL)"
1493 depends on EXPERIMENTAL
1495 This builds a kernel image that retains relocation information
1496 so it can be loaded someplace besides the default 1MB.
1497 The relocations tend to make the kernel binary about 10% larger,
1498 but are discarded at runtime.
1500 One use is for the kexec on panic case where the recovery kernel
1501 must live at a different physical address than the primary
1504 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1505 it has been loaded at and the compile time physical address
1506 (CONFIG_PHYSICAL_START) is ignored.
1508 config PHYSICAL_ALIGN
1510 prompt "Alignment value to which kernel should be aligned" if X86_32
1511 default "0x100000" if X86_32
1512 default "0x200000" if X86_64
1513 range 0x2000 0x400000
1515 This value puts the alignment restrictions on physical address
1516 where kernel is loaded and run from. Kernel is compiled for an
1517 address which meets above alignment restriction.
1519 If bootloader loads the kernel at a non-aligned address and
1520 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1521 address aligned to above value and run from there.
1523 If bootloader loads the kernel at a non-aligned address and
1524 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1525 load address and decompress itself to the address it has been
1526 compiled for and run from there. The address for which kernel is
1527 compiled already meets above alignment restrictions. Hence the
1528 end result is that kernel runs from a physical address meeting
1529 above alignment restrictions.
1531 Don't change this unless you know what you are doing.
1534 bool "Support for hot-pluggable CPUs"
1535 depends on SMP && HOTPLUG
1537 Say Y here to allow turning CPUs off and on. CPUs can be
1538 controlled through /sys/devices/system/cpu.
1539 ( Note: power management support will enable this option
1540 automatically on SMP systems. )
1541 Say N if you want to disable CPU hotplug.
1545 prompt "Compat VDSO support"
1546 depends on X86_32 || IA32_EMULATION
1548 Map the 32-bit VDSO to the predictable old-style address too.
1550 Say N here if you are running a sufficiently recent glibc
1551 version (2.3.3 or later), to remove the high-mapped
1552 VDSO mapping and to exclusively use the randomized VDSO.
1557 bool "Built-in kernel command line"
1560 Allow for specifying boot arguments to the kernel at
1561 build time. On some systems (e.g. embedded ones), it is
1562 necessary or convenient to provide some or all of the
1563 kernel boot arguments with the kernel itself (that is,
1564 to not rely on the boot loader to provide them.)
1566 To compile command line arguments into the kernel,
1567 set this option to 'Y', then fill in the
1568 the boot arguments in CONFIG_CMDLINE.
1570 Systems with fully functional boot loaders (i.e. non-embedded)
1571 should leave this option set to 'N'.
1574 string "Built-in kernel command string"
1575 depends on CMDLINE_BOOL
1578 Enter arguments here that should be compiled into the kernel
1579 image and used at boot time. If the boot loader provides a
1580 command line at boot time, it is appended to this string to
1581 form the full kernel command line, when the system boots.
1583 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1584 change this behavior.
1586 In most cases, the command line (whether built-in or provided
1587 by the boot loader) should specify the device for the root
1590 config CMDLINE_OVERRIDE
1591 bool "Built-in command line overrides boot loader arguments"
1593 depends on CMDLINE_BOOL
1595 Set this option to 'Y' to have the kernel ignore the boot loader
1596 command line, and use ONLY the built-in command line.
1598 This is used to work around broken boot loaders. This should
1599 be set to 'N' under normal conditions.
1603 config ARCH_ENABLE_MEMORY_HOTPLUG
1605 depends on X86_64 || (X86_32 && HIGHMEM)
1607 config ARCH_ENABLE_MEMORY_HOTREMOVE
1609 depends on MEMORY_HOTPLUG
1611 config HAVE_ARCH_EARLY_PFN_TO_NID
1615 menu "Power management and ACPI options"
1617 config ARCH_HIBERNATION_HEADER
1619 depends on X86_64 && HIBERNATION
1621 source "kernel/power/Kconfig"
1623 source "drivers/acpi/Kconfig"
1628 depends on APM || APM_MODULE
1631 tristate "APM (Advanced Power Management) BIOS support"
1632 depends on X86_32 && PM_SLEEP
1634 APM is a BIOS specification for saving power using several different
1635 techniques. This is mostly useful for battery powered laptops with
1636 APM compliant BIOSes. If you say Y here, the system time will be
1637 reset after a RESUME operation, the /proc/apm device will provide
1638 battery status information, and user-space programs will receive
1639 notification of APM "events" (e.g. battery status change).
1641 If you select "Y" here, you can disable actual use of the APM
1642 BIOS by passing the "apm=off" option to the kernel at boot time.
1644 Note that the APM support is almost completely disabled for
1645 machines with more than one CPU.
1647 In order to use APM, you will need supporting software. For location
1648 and more information, read <file:Documentation/power/pm.txt> and the
1649 Battery Powered Linux mini-HOWTO, available from
1650 <http://www.tldp.org/docs.html#howto>.
1652 This driver does not spin down disk drives (see the hdparm(8)
1653 manpage ("man 8 hdparm") for that), and it doesn't turn off
1654 VESA-compliant "green" monitors.
1656 This driver does not support the TI 4000M TravelMate and the ACER
1657 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1658 desktop machines also don't have compliant BIOSes, and this driver
1659 may cause those machines to panic during the boot phase.
1661 Generally, if you don't have a battery in your machine, there isn't
1662 much point in using this driver and you should say N. If you get
1663 random kernel OOPSes or reboots that don't seem to be related to
1664 anything, try disabling/enabling this option (or disabling/enabling
1667 Some other things you should try when experiencing seemingly random,
1670 1) make sure that you have enough swap space and that it is
1672 2) pass the "no-hlt" option to the kernel
1673 3) switch on floating point emulation in the kernel and pass
1674 the "no387" option to the kernel
1675 4) pass the "floppy=nodma" option to the kernel
1676 5) pass the "mem=4M" option to the kernel (thereby disabling
1677 all but the first 4 MB of RAM)
1678 6) make sure that the CPU is not over clocked.
1679 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1680 8) disable the cache from your BIOS settings
1681 9) install a fan for the video card or exchange video RAM
1682 10) install a better fan for the CPU
1683 11) exchange RAM chips
1684 12) exchange the motherboard.
1686 To compile this driver as a module, choose M here: the
1687 module will be called apm.
1691 config APM_IGNORE_USER_SUSPEND
1692 bool "Ignore USER SUSPEND"
1694 This option will ignore USER SUSPEND requests. On machines with a
1695 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1696 series notebooks, it is necessary to say Y because of a BIOS bug.
1698 config APM_DO_ENABLE
1699 bool "Enable PM at boot time"
1701 Enable APM features at boot time. From page 36 of the APM BIOS
1702 specification: "When disabled, the APM BIOS does not automatically
1703 power manage devices, enter the Standby State, enter the Suspend
1704 State, or take power saving steps in response to CPU Idle calls."
1705 This driver will make CPU Idle calls when Linux is idle (unless this
1706 feature is turned off -- see "Do CPU IDLE calls", below). This
1707 should always save battery power, but more complicated APM features
1708 will be dependent on your BIOS implementation. You may need to turn
1709 this option off if your computer hangs at boot time when using APM
1710 support, or if it beeps continuously instead of suspending. Turn
1711 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1712 T400CDT. This is off by default since most machines do fine without
1716 bool "Make CPU Idle calls when idle"
1718 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1719 On some machines, this can activate improved power savings, such as
1720 a slowed CPU clock rate, when the machine is idle. These idle calls
1721 are made after the idle loop has run for some length of time (e.g.,
1722 333 mS). On some machines, this will cause a hang at boot time or
1723 whenever the CPU becomes idle. (On machines with more than one CPU,
1724 this option does nothing.)
1726 config APM_DISPLAY_BLANK
1727 bool "Enable console blanking using APM"
1729 Enable console blanking using the APM. Some laptops can use this to
1730 turn off the LCD backlight when the screen blanker of the Linux
1731 virtual console blanks the screen. Note that this is only used by
1732 the virtual console screen blanker, and won't turn off the backlight
1733 when using the X Window system. This also doesn't have anything to
1734 do with your VESA-compliant power-saving monitor. Further, this
1735 option doesn't work for all laptops -- it might not turn off your
1736 backlight at all, or it might print a lot of errors to the console,
1737 especially if you are using gpm.
1739 config APM_ALLOW_INTS
1740 bool "Allow interrupts during APM BIOS calls"
1742 Normally we disable external interrupts while we are making calls to
1743 the APM BIOS as a measure to lessen the effects of a badly behaving
1744 BIOS implementation. The BIOS should reenable interrupts if it
1745 needs to. Unfortunately, some BIOSes do not -- especially those in
1746 many of the newer IBM Thinkpads. If you experience hangs when you
1747 suspend, try setting this to Y. Otherwise, say N.
1751 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1753 source "drivers/cpuidle/Kconfig"
1755 source "drivers/idle/Kconfig"
1760 menu "Bus options (PCI etc.)"
1765 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1767 Find out whether you have a PCI motherboard. PCI is the name of a
1768 bus system, i.e. the way the CPU talks to the other stuff inside
1769 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1770 VESA. If you have PCI, say Y, otherwise N.
1773 prompt "PCI access mode"
1774 depends on X86_32 && PCI
1777 On PCI systems, the BIOS can be used to detect the PCI devices and
1778 determine their configuration. However, some old PCI motherboards
1779 have BIOS bugs and may crash if this is done. Also, some embedded
1780 PCI-based systems don't have any BIOS at all. Linux can also try to
1781 detect the PCI hardware directly without using the BIOS.
1783 With this option, you can specify how Linux should detect the
1784 PCI devices. If you choose "BIOS", the BIOS will be used,
1785 if you choose "Direct", the BIOS won't be used, and if you
1786 choose "MMConfig", then PCI Express MMCONFIG will be used.
1787 If you choose "Any", the kernel will try MMCONFIG, then the
1788 direct access method and falls back to the BIOS if that doesn't
1789 work. If unsure, go with the default, which is "Any".
1794 config PCI_GOMMCONFIG
1811 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1813 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1816 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1820 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1824 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1831 bool "Support mmconfig PCI config space access"
1832 depends on X86_64 && PCI && ACPI
1835 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1836 depends on PCI_MSI && ACPI && EXPERIMENTAL
1838 DMA remapping (DMAR) devices support enables independent address
1839 translations for Direct Memory Access (DMA) from devices.
1840 These DMA remapping devices are reported via ACPI tables
1841 and include PCI device scope covered by these DMA
1844 config DMAR_DEFAULT_ON
1846 prompt "Enable DMA Remapping Devices by default"
1849 Selecting this option will enable a DMAR device at boot time if
1850 one is found. If this option is not selected, DMAR support can
1851 be enabled by passing intel_iommu=on to the kernel. It is
1852 recommended you say N here while the DMAR code remains
1857 prompt "Support for Graphics workaround"
1860 Current Graphics drivers tend to use physical address
1861 for DMA and avoid using DMA APIs. Setting this config
1862 option permits the IOMMU driver to set a unity map for
1863 all the OS-visible memory. Hence the driver can continue
1864 to use physical addresses for DMA.
1866 config DMAR_FLOPPY_WA
1870 Floppy disk drivers are know to bypass DMA API calls
1871 thereby failing to work when IOMMU is enabled. This
1872 workaround will setup a 1:1 mapping for the first
1873 16M to make floppy (an ISA device) work.
1876 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1877 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1879 Supports Interrupt remapping for IO-APIC and MSI devices.
1880 To use x2apic mode in the CPU's which support x2APIC enhancements or
1881 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1883 source "drivers/pci/pcie/Kconfig"
1885 source "drivers/pci/Kconfig"
1887 # x86_64 have no ISA slots, but do have ISA-style DMA.
1896 Find out whether you have ISA slots on your motherboard. ISA is the
1897 name of a bus system, i.e. the way the CPU talks to the other stuff
1898 inside your box. Other bus systems are PCI, EISA, MicroChannel
1899 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1900 newer boards don't support it. If you have ISA, say Y, otherwise N.
1906 The Extended Industry Standard Architecture (EISA) bus was
1907 developed as an open alternative to the IBM MicroChannel bus.
1909 The EISA bus provided some of the features of the IBM MicroChannel
1910 bus while maintaining backward compatibility with cards made for
1911 the older ISA bus. The EISA bus saw limited use between 1988 and
1912 1995 when it was made obsolete by the PCI bus.
1914 Say Y here if you are building a kernel for an EISA-based machine.
1918 source "drivers/eisa/Kconfig"
1923 MicroChannel Architecture is found in some IBM PS/2 machines and
1924 laptops. It is a bus system similar to PCI or ISA. See
1925 <file:Documentation/mca.txt> (and especially the web page given
1926 there) before attempting to build an MCA bus kernel.
1928 source "drivers/mca/Kconfig"
1931 tristate "NatSemi SCx200 support"
1933 This provides basic support for National Semiconductor's
1934 (now AMD's) Geode processors. The driver probes for the
1935 PCI-IDs of several on-chip devices, so its a good dependency
1936 for other scx200_* drivers.
1938 If compiled as a module, the driver is named scx200.
1940 config SCx200HR_TIMER
1941 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1942 depends on SCx200 && GENERIC_TIME
1945 This driver provides a clocksource built upon the on-chip
1946 27MHz high-resolution timer. Its also a workaround for
1947 NSC Geode SC-1100's buggy TSC, which loses time when the
1948 processor goes idle (as is done by the scheduler). The
1949 other workaround is idle=poll boot option.
1951 config GEODE_MFGPT_TIMER
1953 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1954 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1956 This driver provides a clock event source based on the MFGPT
1957 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1958 MFGPTs have a better resolution and max interval than the
1959 generic PIT, and are suitable for use as high-res timers.
1962 bool "One Laptop Per Child support"
1965 Add support for detecting the unique features of the OLPC
1972 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1974 source "drivers/pcmcia/Kconfig"
1976 source "drivers/pci/hotplug/Kconfig"
1981 menu "Executable file formats / Emulations"
1983 source "fs/Kconfig.binfmt"
1985 config IA32_EMULATION
1986 bool "IA32 Emulation"
1988 select COMPAT_BINFMT_ELF
1990 Include code to run 32-bit programs under a 64-bit kernel. You should
1991 likely turn this on, unless you're 100% sure that you don't have any
1992 32-bit programs left.
1995 tristate "IA32 a.out support"
1996 depends on IA32_EMULATION
1998 Support old a.out binaries in the 32bit emulation.
2002 depends on IA32_EMULATION
2004 config COMPAT_FOR_U64_ALIGNMENT
2008 config SYSVIPC_COMPAT
2010 depends on COMPAT && SYSVIPC
2015 config HAVE_ATOMIC_IOMAP
2019 source "net/Kconfig"
2021 source "drivers/Kconfig"
2023 source "drivers/firmware/Kconfig"
2027 source "arch/x86/Kconfig.debug"
2029 source "security/Kconfig"
2031 source "crypto/Kconfig"
2033 source "arch/x86/kvm/Kconfig"
2035 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob