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 HAVE_KRETPROBES
31 select HAVE_FTRACE_MCOUNT_RECORD
32 select HAVE_DYNAMIC_FTRACE
33 select HAVE_FUNCTION_TRACER
34 select HAVE_FUNCTION_GRAPH_TRACER
35 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
36 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
37 select HAVE_ARCH_KGDB if !X86_VOYAGER
38 select HAVE_ARCH_TRACEHOOK
39 select HAVE_GENERIC_DMA_COHERENT if X86_32
40 select HAVE_EFFICIENT_UNALIGNED_ACCESS
41 select USER_STACKTRACE_SUPPORT
42 select HAVE_KERNEL_GZIP
43 select HAVE_KERNEL_BZIP2
44 select HAVE_KERNEL_LZMA
48 default "arch/x86/configs/i386_defconfig" if X86_32
49 default "arch/x86/configs/x86_64_defconfig" if X86_64
54 config GENERIC_CMOS_UPDATE
57 config CLOCKSOURCE_WATCHDOG
60 config GENERIC_CLOCKEVENTS
63 config GENERIC_CLOCKEVENTS_BROADCAST
65 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
67 config LOCKDEP_SUPPORT
70 config STACKTRACE_SUPPORT
73 config HAVE_LATENCYTOP_SUPPORT
76 config FAST_CMPXCHG_LOCAL
89 config GENERIC_ISA_DMA
98 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
100 config GENERIC_BUG_RELATIVE_POINTERS
103 config GENERIC_HWEIGHT
109 config ARCH_MAY_HAVE_PC_FDC
112 config RWSEM_GENERIC_SPINLOCK
115 config RWSEM_XCHGADD_ALGORITHM
118 config ARCH_HAS_CPU_IDLE_WAIT
121 config GENERIC_CALIBRATE_DELAY
124 config GENERIC_TIME_VSYSCALL
128 config ARCH_HAS_CPU_RELAX
131 config ARCH_HAS_DEFAULT_IDLE
134 config ARCH_HAS_CACHE_LINE_SIZE
137 config HAVE_SETUP_PER_CPU_AREA
138 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
140 config HAVE_CPUMASK_OF_CPU_MAP
143 config ARCH_HIBERNATION_POSSIBLE
145 depends on !SMP || !X86_VOYAGER
147 config ARCH_SUSPEND_POSSIBLE
149 depends on !X86_VOYAGER
155 config ARCH_POPULATES_NODE_MAP
162 config ARCH_SUPPORTS_OPTIMIZED_INLINING
165 # Use the generic interrupt handling code in kernel/irq/:
166 config GENERIC_HARDIRQS
170 config GENERIC_IRQ_PROBE
174 config GENERIC_PENDING_IRQ
176 depends on GENERIC_HARDIRQS && SMP
181 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
184 config USE_GENERIC_SMP_HELPERS
190 depends on X86_32 && SMP
194 depends on X86_64 && SMP
199 depends on (X86_32 && !X86_VOYAGER) || X86_64
202 config X86_BIOS_REBOOT
204 depends on !X86_VOYAGER
207 config X86_TRAMPOLINE
209 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
214 source "init/Kconfig"
215 source "kernel/Kconfig.freezer"
217 menu "Processor type and features"
219 source "kernel/time/Kconfig"
222 bool "Symmetric multi-processing support"
224 This enables support for systems with more than one CPU. If you have
225 a system with only one CPU, like most personal computers, say N. If
226 you have a system with more than one CPU, say Y.
228 If you say N here, the kernel will run on single and multiprocessor
229 machines, but will use only one CPU of a multiprocessor machine. If
230 you say Y here, the kernel will run on many, but not all,
231 singleprocessor machines. On a singleprocessor machine, the kernel
232 will run faster if you say N here.
234 Note that if you say Y here and choose architecture "586" or
235 "Pentium" under "Processor family", the kernel will not work on 486
236 architectures. Similarly, multiprocessor kernels for the "PPro"
237 architecture may not work on all Pentium based boards.
239 People using multiprocessor machines who say Y here should also say
240 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
241 Management" code will be disabled if you say Y here.
243 See also <file:Documentation/i386/IO-APIC.txt>,
244 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
245 <http://www.tldp.org/docs.html#howto>.
247 If you don't know what to do here, say N.
249 config X86_HAS_BOOT_CPU_ID
251 depends on X86_VOYAGER
254 bool "Support sparse irq numbering"
255 depends on PCI_MSI || HT_IRQ
257 This enables support for sparse irqs. This is useful for distro
258 kernels that want to define a high CONFIG_NR_CPUS value but still
259 want to have low kernel memory footprint on smaller machines.
261 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
262 out the irq_desc[] array in a more NUMA-friendly way. )
264 If you don't know what to do here, say N.
266 config NUMA_MIGRATE_IRQ_DESC
267 bool "Move irq desc when changing irq smp_affinity"
268 depends on SPARSE_IRQ && NUMA
271 This enables moving irq_desc to cpu/node that irq will use handled.
273 If you don't know what to do here, say N.
275 config X86_FIND_SMP_CONFIG
277 depends on X86_MPPARSE || X86_VOYAGER
280 bool "Enable MPS table" if ACPI
282 depends on X86_LOCAL_APIC
284 For old smp systems that do not have proper acpi support. Newer systems
285 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
288 prompt "Subarchitecture Type"
294 Choose this option if your computer is a standard PC or compatible.
300 Select this for an AMD Elan processor.
302 Do not use this option for K6/Athlon/Opteron processors!
304 If unsure, choose "PC-compatible" instead.
308 depends on X86_32 && (SMP || BROKEN) && !PCI
310 Voyager is an MCA-based 32-way capable SMP architecture proprietary
311 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
315 If you do not specifically know you have a Voyager based machine,
316 say N here, otherwise the kernel you build will not be bootable.
318 config X86_GENERICARCH
319 bool "Generic architecture"
322 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
323 subarchitectures. It is intended for a generic binary kernel.
324 if you select them all, kernel will probe it one by one. and will
330 bool "NUMAQ (IBM/Sequent)"
331 depends on SMP && X86_32 && PCI && X86_MPPARSE
334 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
335 NUMA multiquad box. This changes the way that processors are
336 bootstrapped, and uses Clustered Logical APIC addressing mode instead
337 of Flat Logical. You will need a new lynxer.elf file to flash your
338 firmware with - send email to <Martin.Bligh@us.ibm.com>.
341 bool "Summit/EXA (IBM x440)"
342 depends on X86_32 && SMP
344 This option is needed for IBM systems that use the Summit/EXA chipset.
345 In particular, it is needed for the x440.
348 bool "Support for Unisys ES7000 IA32 series"
349 depends on X86_32 && SMP
351 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
352 supposed to run on an IA32-based Unisys ES7000 system.
355 bool "Support for big SMP systems with more than 8 CPUs"
356 depends on X86_32 && SMP
358 This option is needed for the systems that have more than 8 CPUs
359 and if the system is not of any sub-arch type above.
364 bool "Support for ScaleMP vSMP"
366 depends on X86_64 && PCI
368 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
369 supposed to run on these EM64T-based machines. Only choose this option
370 if you have one of these machines.
375 bool "SGI 320/540 (Visual Workstation)"
376 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
378 The SGI Visual Workstation series is an IA32-based workstation
379 based on SGI systems chips with some legacy PC hardware attached.
381 Say Y here to create a kernel to run on the SGI 320 or 540.
383 A kernel compiled for the Visual Workstation will run on general
384 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
387 bool "RDC R-321x SoC"
390 select X86_REBOOTFIXUPS
392 This option is needed for RDC R-321x system-on-chip, also known
394 If you don't have one of these chips, you should say N here.
396 config SCHED_OMIT_FRAME_POINTER
398 prompt "Single-depth WCHAN output"
401 Calculate simpler /proc/<PID>/wchan values. If this option
402 is disabled then wchan values will recurse back to the
403 caller function. This provides more accurate wchan values,
404 at the expense of slightly more scheduling overhead.
406 If in doubt, say "Y".
408 menuconfig PARAVIRT_GUEST
409 bool "Paravirtualized guest support"
411 Say Y here to get to see options related to running Linux under
412 various hypervisors. This option alone does not add any kernel code.
414 If you say N, all options in this submenu will be skipped and disabled.
418 source "arch/x86/xen/Kconfig"
421 bool "VMI Guest support"
424 depends on !X86_VOYAGER
426 VMI provides a paravirtualized interface to the VMware ESX server
427 (it could be used by other hypervisors in theory too, but is not
428 at the moment), by linking the kernel to a GPL-ed ROM module
429 provided by the hypervisor.
432 bool "KVM paravirtualized clock"
434 select PARAVIRT_CLOCK
435 depends on !X86_VOYAGER
437 Turning on this option will allow you to run a paravirtualized clock
438 when running over the KVM hypervisor. Instead of relying on a PIT
439 (or probably other) emulation by the underlying device model, the host
440 provides the guest with timing infrastructure such as time of day, and
444 bool "KVM Guest support"
446 depends on !X86_VOYAGER
448 This option enables various optimizations for running under the KVM
451 source "arch/x86/lguest/Kconfig"
454 bool "Enable paravirtualization code"
455 depends on !X86_VOYAGER
457 This changes the kernel so it can modify itself when it is run
458 under a hypervisor, potentially improving performance significantly
459 over full virtualization. However, when run without a hypervisor
460 the kernel is theoretically slower and slightly larger.
462 config PARAVIRT_CLOCK
468 config PARAVIRT_DEBUG
469 bool "paravirt-ops debugging"
470 depends on PARAVIRT && DEBUG_KERNEL
472 Enable to debug paravirt_ops internals. Specifically, BUG if
473 a paravirt_op is missing when it is called.
478 This option adds a kernel parameter 'memtest', which allows memtest
480 memtest=0, mean disabled; -- default
481 memtest=1, mean do 1 test pattern;
483 memtest=4, mean do 4 test patterns.
484 If you are unsure how to answer this question, answer N.
486 config X86_SUMMIT_NUMA
488 depends on X86_32 && NUMA && X86_GENERICARCH
490 config X86_CYCLONE_TIMER
492 depends on X86_GENERICARCH
494 source "arch/x86/Kconfig.cpu"
498 prompt "HPET Timer Support" if X86_32
500 Use the IA-PC HPET (High Precision Event Timer) to manage
501 time in preference to the PIT and RTC, if a HPET is
503 HPET is the next generation timer replacing legacy 8254s.
504 The HPET provides a stable time base on SMP
505 systems, unlike the TSC, but it is more expensive to access,
506 as it is off-chip. You can find the HPET spec at
507 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
509 You can safely choose Y here. However, HPET will only be
510 activated if the platform and the BIOS support this feature.
511 Otherwise the 8254 will be used for timing services.
513 Choose N to continue using the legacy 8254 timer.
515 config HPET_EMULATE_RTC
517 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
519 # Mark as embedded because too many people got it wrong.
520 # The code disables itself when not needed.
523 bool "Enable DMI scanning" if EMBEDDED
525 Enabled scanning of DMI to identify machine quirks. Say Y
526 here unless you have verified that your setup is not
527 affected by entries in the DMI blacklist. Required by PNP
531 bool "GART IOMMU support" if EMBEDDED
535 depends on X86_64 && PCI
537 Support for full DMA access of devices with 32bit memory access only
538 on systems with more than 3GB. This is usually needed for USB,
539 sound, many IDE/SATA chipsets and some other devices.
540 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
541 based hardware IOMMU and a software bounce buffer based IOMMU used
542 on Intel systems and as fallback.
543 The code is only active when needed (enough memory and limited
544 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
548 bool "IBM Calgary IOMMU support"
550 depends on X86_64 && PCI && EXPERIMENTAL
552 Support for hardware IOMMUs in IBM's xSeries x366 and x460
553 systems. Needed to run systems with more than 3GB of memory
554 properly with 32-bit PCI devices that do not support DAC
555 (Double Address Cycle). Calgary also supports bus level
556 isolation, where all DMAs pass through the IOMMU. This
557 prevents them from going anywhere except their intended
558 destination. This catches hard-to-find kernel bugs and
559 mis-behaving drivers and devices that do not use the DMA-API
560 properly to set up their DMA buffers. The IOMMU can be
561 turned off at boot time with the iommu=off parameter.
562 Normally the kernel will make the right choice by itself.
565 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
567 prompt "Should Calgary be enabled by default?"
568 depends on CALGARY_IOMMU
570 Should Calgary be enabled by default? if you choose 'y', Calgary
571 will be used (if it exists). If you choose 'n', Calgary will not be
572 used even if it exists. If you choose 'n' and would like to use
573 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
577 bool "AMD IOMMU support"
580 depends on X86_64 && PCI && ACPI
582 With this option you can enable support for AMD IOMMU hardware in
583 your system. An IOMMU is a hardware component which provides
584 remapping of DMA memory accesses from devices. With an AMD IOMMU you
585 can isolate the the DMA memory of different devices and protect the
586 system from misbehaving device drivers or hardware.
588 You can find out if your system has an AMD IOMMU if you look into
589 your BIOS for an option to enable it or if you have an IVRS ACPI
592 config AMD_IOMMU_STATS
593 bool "Export AMD IOMMU statistics to debugfs"
597 This option enables code in the AMD IOMMU driver to collect various
598 statistics about whats happening in the driver and exports that
599 information to userspace via debugfs.
602 # need this always selected by IOMMU for the VIA workaround
606 Support for software bounce buffers used on x86-64 systems
607 which don't have a hardware IOMMU (e.g. the current generation
608 of Intel's x86-64 CPUs). Using this PCI devices which can only
609 access 32-bits of memory can be used on systems with more than
610 3 GB of memory. If unsure, say Y.
613 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
616 def_bool (AMD_IOMMU || DMAR)
619 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
620 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
621 select CPUMASK_OFFSTACK
624 Configure maximum number of CPUS and NUMA Nodes for this architecture.
628 int "Maximum number of CPUs" if SMP && !MAXSMP
629 range 2 512 if SMP && !MAXSMP
631 default "4096" if MAXSMP
632 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
635 This allows you to specify the maximum number of CPUs which this
636 kernel will support. The maximum supported value is 512 and the
637 minimum value which makes sense is 2.
639 This is purely to save memory - each supported CPU adds
640 approximately eight kilobytes to the kernel image.
643 bool "SMT (Hyperthreading) scheduler support"
646 SMT scheduler support improves the CPU scheduler's decision making
647 when dealing with Intel Pentium 4 chips with HyperThreading at a
648 cost of slightly increased overhead in some places. If unsure say
653 prompt "Multi-core scheduler support"
656 Multi-core scheduler support improves the CPU scheduler's decision
657 making when dealing with multi-core CPU chips at a cost of slightly
658 increased overhead in some places. If unsure say N here.
660 source "kernel/Kconfig.preempt"
663 bool "Local APIC support on uniprocessors"
664 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
666 A local APIC (Advanced Programmable Interrupt Controller) is an
667 integrated interrupt controller in the CPU. If you have a single-CPU
668 system which has a processor with a local APIC, you can say Y here to
669 enable and use it. If you say Y here even though your machine doesn't
670 have a local APIC, then the kernel will still run with no slowdown at
671 all. The local APIC supports CPU-generated self-interrupts (timer,
672 performance counters), and the NMI watchdog which detects hard
676 bool "IO-APIC support on uniprocessors"
677 depends on X86_UP_APIC
679 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
680 SMP-capable replacement for PC-style interrupt controllers. Most
681 SMP systems and many recent uniprocessor systems have one.
683 If you have a single-CPU system with an IO-APIC, you can say Y here
684 to use it. If you say Y here even though your machine doesn't have
685 an IO-APIC, then the kernel will still run with no slowdown at all.
687 config X86_LOCAL_APIC
689 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
693 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
695 config X86_VISWS_APIC
697 depends on X86_32 && X86_VISWS
699 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
700 bool "Reroute for broken boot IRQs"
702 depends on X86_IO_APIC
704 This option enables a workaround that fixes a source of
705 spurious interrupts. This is recommended when threaded
706 interrupt handling is used on systems where the generation of
707 superfluous "boot interrupts" cannot be disabled.
709 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
710 entry in the chipset's IO-APIC is masked (as, e.g. the RT
711 kernel does during interrupt handling). On chipsets where this
712 boot IRQ generation cannot be disabled, this workaround keeps
713 the original IRQ line masked so that only the equivalent "boot
714 IRQ" is delivered to the CPUs. The workaround also tells the
715 kernel to set up the IRQ handler on the boot IRQ line. In this
716 way only one interrupt is delivered to the kernel. Otherwise
717 the spurious second interrupt may cause the kernel to bring
718 down (vital) interrupt lines.
720 Only affects "broken" chipsets. Interrupt sharing may be
721 increased on these systems.
724 bool "Machine Check Exception"
725 depends on !X86_VOYAGER
727 Machine Check Exception support allows the processor to notify the
728 kernel if it detects a problem (e.g. overheating, component failure).
729 The action the kernel takes depends on the severity of the problem,
730 ranging from a warning message on the console, to halting the machine.
731 Your processor must be a Pentium or newer to support this - check the
732 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
733 have a design flaw which leads to false MCE events - hence MCE is
734 disabled on all P5 processors, unless explicitly enabled with "mce"
735 as a boot argument. Similarly, if MCE is built in and creates a
736 problem on some new non-standard machine, you can boot with "nomce"
737 to disable it. MCE support simply ignores non-MCE processors like
738 the 386 and 486, so nearly everyone can say Y here.
742 prompt "Intel MCE features"
743 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
745 Additional support for intel specific MCE features such as
750 prompt "AMD MCE features"
751 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
753 Additional support for AMD specific MCE features such as
754 the DRAM Error Threshold.
756 config X86_MCE_NONFATAL
757 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
758 depends on X86_32 && X86_MCE
760 Enabling this feature starts a timer that triggers every 5 seconds which
761 will look at the machine check registers to see if anything happened.
762 Non-fatal problems automatically get corrected (but still logged).
763 Disable this if you don't want to see these messages.
764 Seeing the messages this option prints out may be indicative of dying
765 or out-of-spec (ie, overclocked) hardware.
766 This option only does something on certain CPUs.
767 (AMD Athlon/Duron and Intel Pentium 4)
769 config X86_MCE_P4THERMAL
770 bool "check for P4 thermal throttling interrupt."
771 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
773 Enabling this feature will cause a message to be printed when the P4
774 enters thermal throttling.
777 bool "Enable VM86 support" if EMBEDDED
781 This option is required by programs like DOSEMU to run 16-bit legacy
782 code on X86 processors. It also may be needed by software like
783 XFree86 to initialize some video cards via BIOS. Disabling this
784 option saves about 6k.
787 tristate "Toshiba Laptop support"
790 This adds a driver to safely access the System Management Mode of
791 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
792 not work on models with a Phoenix BIOS. The System Management Mode
793 is used to set the BIOS and power saving options on Toshiba portables.
795 For information on utilities to make use of this driver see the
796 Toshiba Linux utilities web site at:
797 <http://www.buzzard.org.uk/toshiba/>.
799 Say Y if you intend to run this kernel on a Toshiba portable.
803 tristate "Dell laptop support"
805 This adds a driver to safely access the System Management Mode
806 of the CPU on the Dell Inspiron 8000. The System Management Mode
807 is used to read cpu temperature and cooling fan status and to
808 control the fans on the I8K portables.
810 This driver has been tested only on the Inspiron 8000 but it may
811 also work with other Dell laptops. You can force loading on other
812 models by passing the parameter `force=1' to the module. Use at
815 For information on utilities to make use of this driver see the
816 I8K Linux utilities web site at:
817 <http://people.debian.org/~dz/i8k/>
819 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
822 config X86_REBOOTFIXUPS
823 bool "Enable X86 board specific fixups for reboot"
826 This enables chipset and/or board specific fixups to be done
827 in order to get reboot to work correctly. This is only needed on
828 some combinations of hardware and BIOS. The symptom, for which
829 this config is intended, is when reboot ends with a stalled/hung
832 Currently, the only fixup is for the Geode machines using
833 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
835 Say Y if you want to enable the fixup. Currently, it's safe to
836 enable this option even if you don't need it.
840 tristate "/dev/cpu/microcode - microcode support"
843 If you say Y here, you will be able to update the microcode on
844 certain Intel and AMD processors. The Intel support is for the
845 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
846 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
847 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
848 You will obviously need the actual microcode binary data itself
849 which is not shipped with the Linux kernel.
851 This option selects the general module only, you need to select
852 at least one vendor specific module as well.
854 To compile this driver as a module, choose M here: the
855 module will be called microcode.
857 config MICROCODE_INTEL
858 bool "Intel microcode patch loading support"
863 This options enables microcode patch loading support for Intel
866 For latest news and information on obtaining all the required
867 Intel ingredients for this driver, check:
868 <http://www.urbanmyth.org/microcode/>.
871 bool "AMD microcode patch loading support"
875 If you select this option, microcode patch loading support for AMD
876 processors will be enabled.
878 config MICROCODE_OLD_INTERFACE
883 tristate "/dev/cpu/*/msr - Model-specific register support"
885 This device gives privileged processes access to the x86
886 Model-Specific Registers (MSRs). It is a character device with
887 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
888 MSR accesses are directed to a specific CPU on multi-processor
892 tristate "/dev/cpu/*/cpuid - CPU information support"
894 This device gives processes access to the x86 CPUID instruction to
895 be executed on a specific processor. It is a character device
896 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
900 prompt "High Memory Support"
901 default HIGHMEM4G if !X86_NUMAQ
902 default HIGHMEM64G if X86_NUMAQ
907 depends on !X86_NUMAQ
909 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
910 However, the address space of 32-bit x86 processors is only 4
911 Gigabytes large. That means that, if you have a large amount of
912 physical memory, not all of it can be "permanently mapped" by the
913 kernel. The physical memory that's not permanently mapped is called
916 If you are compiling a kernel which will never run on a machine with
917 more than 1 Gigabyte total physical RAM, answer "off" here (default
918 choice and suitable for most users). This will result in a "3GB/1GB"
919 split: 3GB are mapped so that each process sees a 3GB virtual memory
920 space and the remaining part of the 4GB virtual memory space is used
921 by the kernel to permanently map as much physical memory as
924 If the machine has between 1 and 4 Gigabytes physical RAM, then
927 If more than 4 Gigabytes is used then answer "64GB" here. This
928 selection turns Intel PAE (Physical Address Extension) mode on.
929 PAE implements 3-level paging on IA32 processors. PAE is fully
930 supported by Linux, PAE mode is implemented on all recent Intel
931 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
932 then the kernel will not boot on CPUs that don't support PAE!
934 The actual amount of total physical memory will either be
935 auto detected or can be forced by using a kernel command line option
936 such as "mem=256M". (Try "man bootparam" or see the documentation of
937 your boot loader (lilo or loadlin) about how to pass options to the
938 kernel at boot time.)
940 If unsure, say "off".
944 depends on !X86_NUMAQ
946 Select this if you have a 32-bit processor and between 1 and 4
947 gigabytes of physical RAM.
951 depends on !M386 && !M486
954 Select this if you have a 32-bit processor and more than 4
955 gigabytes of physical RAM.
960 depends on EXPERIMENTAL
961 prompt "Memory split" if EMBEDDED
965 Select the desired split between kernel and user memory.
967 If the address range available to the kernel is less than the
968 physical memory installed, the remaining memory will be available
969 as "high memory". Accessing high memory is a little more costly
970 than low memory, as it needs to be mapped into the kernel first.
971 Note that increasing the kernel address space limits the range
972 available to user programs, making the address space there
973 tighter. Selecting anything other than the default 3G/1G split
974 will also likely make your kernel incompatible with binary-only
977 If you are not absolutely sure what you are doing, leave this
981 bool "3G/1G user/kernel split"
982 config VMSPLIT_3G_OPT
984 bool "3G/1G user/kernel split (for full 1G low memory)"
986 bool "2G/2G user/kernel split"
987 config VMSPLIT_2G_OPT
989 bool "2G/2G user/kernel split (for full 2G low memory)"
991 bool "1G/3G user/kernel split"
996 default 0xB0000000 if VMSPLIT_3G_OPT
997 default 0x80000000 if VMSPLIT_2G
998 default 0x78000000 if VMSPLIT_2G_OPT
999 default 0x40000000 if VMSPLIT_1G
1005 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1008 bool "PAE (Physical Address Extension) Support"
1009 depends on X86_32 && !HIGHMEM4G
1011 PAE is required for NX support, and furthermore enables
1012 larger swapspace support for non-overcommit purposes. It
1013 has the cost of more pagetable lookup overhead, and also
1014 consumes more pagetable space per process.
1016 config ARCH_PHYS_ADDR_T_64BIT
1017 def_bool X86_64 || X86_PAE
1019 config DIRECT_GBPAGES
1020 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1024 Allow the kernel linear mapping to use 1GB pages on CPUs that
1025 support it. This can improve the kernel's performance a tiny bit by
1026 reducing TLB pressure. If in doubt, say "Y".
1028 # Common NUMA Features
1030 bool "Numa Memory Allocation and Scheduler Support"
1032 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1034 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1036 Enable NUMA (Non Uniform Memory Access) support.
1038 The kernel will try to allocate memory used by a CPU on the
1039 local memory controller of the CPU and add some more
1040 NUMA awareness to the kernel.
1042 For 64-bit this is recommended if the system is Intel Core i7
1043 (or later), AMD Opteron, or EM64T NUMA.
1045 For 32-bit this is only needed on (rare) 32-bit-only platforms
1046 that support NUMA topologies, such as NUMAQ / Summit, or if you
1047 boot a 32-bit kernel on a 64-bit NUMA platform.
1049 Otherwise, you should say N.
1051 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1052 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1056 prompt "Old style AMD Opteron NUMA detection"
1057 depends on X86_64 && NUMA && PCI
1059 Enable K8 NUMA node topology detection. You should say Y here if
1060 you have a multi processor AMD K8 system. This uses an old
1061 method to read the NUMA configuration directly from the builtin
1062 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1063 instead, which also takes priority if both are compiled in.
1065 config X86_64_ACPI_NUMA
1067 prompt "ACPI NUMA detection"
1068 depends on X86_64 && NUMA && ACPI && PCI
1071 Enable ACPI SRAT based node topology detection.
1073 # Some NUMA nodes have memory ranges that span
1074 # other nodes. Even though a pfn is valid and
1075 # between a node's start and end pfns, it may not
1076 # reside on that node. See memmap_init_zone()
1078 config NODES_SPAN_OTHER_NODES
1080 depends on X86_64_ACPI_NUMA
1083 bool "NUMA emulation"
1084 depends on X86_64 && NUMA
1086 Enable NUMA emulation. A flat machine will be split
1087 into virtual nodes when booted with "numa=fake=N", where N is the
1088 number of nodes. This is only useful for debugging.
1091 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1093 default "9" if MAXSMP
1094 default "6" if X86_64
1095 default "4" if X86_NUMAQ
1097 depends on NEED_MULTIPLE_NODES
1099 Specify the maximum number of NUMA Nodes available on the target
1100 system. Increases memory reserved to accomodate various tables.
1102 config HAVE_ARCH_BOOTMEM_NODE
1104 depends on X86_32 && NUMA
1106 config ARCH_HAVE_MEMORY_PRESENT
1108 depends on X86_32 && DISCONTIGMEM
1110 config NEED_NODE_MEMMAP_SIZE
1112 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1114 config HAVE_ARCH_ALLOC_REMAP
1116 depends on X86_32 && NUMA
1118 config ARCH_FLATMEM_ENABLE
1120 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1122 config ARCH_DISCONTIGMEM_ENABLE
1124 depends on NUMA && X86_32
1126 config ARCH_DISCONTIGMEM_DEFAULT
1128 depends on NUMA && X86_32
1130 config ARCH_SPARSEMEM_DEFAULT
1134 config ARCH_SPARSEMEM_ENABLE
1136 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1137 select SPARSEMEM_STATIC if X86_32
1138 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1140 config ARCH_SELECT_MEMORY_MODEL
1142 depends on ARCH_SPARSEMEM_ENABLE
1144 config ARCH_MEMORY_PROBE
1146 depends on MEMORY_HOTPLUG
1151 bool "Allocate 3rd-level pagetables from highmem"
1152 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1154 The VM uses one page table entry for each page of physical memory.
1155 For systems with a lot of RAM, this can be wasteful of precious
1156 low memory. Setting this option will put user-space page table
1157 entries in high memory.
1159 config X86_CHECK_BIOS_CORRUPTION
1160 bool "Check for low memory corruption"
1162 Periodically check for memory corruption in low memory, which
1163 is suspected to be caused by BIOS. Even when enabled in the
1164 configuration, it is disabled at runtime. Enable it by
1165 setting "memory_corruption_check=1" on the kernel command
1166 line. By default it scans the low 64k of memory every 60
1167 seconds; see the memory_corruption_check_size and
1168 memory_corruption_check_period parameters in
1169 Documentation/kernel-parameters.txt to adjust this.
1171 When enabled with the default parameters, this option has
1172 almost no overhead, as it reserves a relatively small amount
1173 of memory and scans it infrequently. It both detects corruption
1174 and prevents it from affecting the running system.
1176 It is, however, intended as a diagnostic tool; if repeatable
1177 BIOS-originated corruption always affects the same memory,
1178 you can use memmap= to prevent the kernel from using that
1181 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1182 bool "Set the default setting of memory_corruption_check"
1183 depends on X86_CHECK_BIOS_CORRUPTION
1186 Set whether the default state of memory_corruption_check is
1189 config X86_RESERVE_LOW_64K
1190 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1193 Reserve the first 64K of physical RAM on BIOSes that are known
1194 to potentially corrupt that memory range. A numbers of BIOSes are
1195 known to utilize this area during suspend/resume, so it must not
1196 be used by the kernel.
1198 Set this to N if you are absolutely sure that you trust the BIOS
1199 to get all its memory reservations and usages right.
1201 If you have doubts about the BIOS (e.g. suspend/resume does not
1202 work or there's kernel crashes after certain hardware hotplug
1203 events) and it's not AMI or Phoenix, then you might want to enable
1204 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1205 corruption patterns.
1209 config MATH_EMULATION
1211 prompt "Math emulation" if X86_32
1213 Linux can emulate a math coprocessor (used for floating point
1214 operations) if you don't have one. 486DX and Pentium processors have
1215 a math coprocessor built in, 486SX and 386 do not, unless you added
1216 a 487DX or 387, respectively. (The messages during boot time can
1217 give you some hints here ["man dmesg"].) Everyone needs either a
1218 coprocessor or this emulation.
1220 If you don't have a math coprocessor, you need to say Y here; if you
1221 say Y here even though you have a coprocessor, the coprocessor will
1222 be used nevertheless. (This behavior can be changed with the kernel
1223 command line option "no387", which comes handy if your coprocessor
1224 is broken. Try "man bootparam" or see the documentation of your boot
1225 loader (lilo or loadlin) about how to pass options to the kernel at
1226 boot time.) This means that it is a good idea to say Y here if you
1227 intend to use this kernel on different machines.
1229 More information about the internals of the Linux math coprocessor
1230 emulation can be found in <file:arch/x86/math-emu/README>.
1232 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1233 kernel, it won't hurt.
1236 bool "MTRR (Memory Type Range Register) support"
1238 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1239 the Memory Type Range Registers (MTRRs) may be used to control
1240 processor access to memory ranges. This is most useful if you have
1241 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1242 allows bus write transfers to be combined into a larger transfer
1243 before bursting over the PCI/AGP bus. This can increase performance
1244 of image write operations 2.5 times or more. Saying Y here creates a
1245 /proc/mtrr file which may be used to manipulate your processor's
1246 MTRRs. Typically the X server should use this.
1248 This code has a reasonably generic interface so that similar
1249 control registers on other processors can be easily supported
1252 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1253 Registers (ARRs) which provide a similar functionality to MTRRs. For
1254 these, the ARRs are used to emulate the MTRRs.
1255 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1256 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1257 write-combining. All of these processors are supported by this code
1258 and it makes sense to say Y here if you have one of them.
1260 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1261 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1262 can lead to all sorts of problems, so it's good to say Y here.
1264 You can safely say Y even if your machine doesn't have MTRRs, you'll
1265 just add about 9 KB to your kernel.
1267 See <file:Documentation/x86/mtrr.txt> for more information.
1269 config MTRR_SANITIZER
1271 prompt "MTRR cleanup support"
1274 Convert MTRR layout from continuous to discrete, so X drivers can
1275 add writeback entries.
1277 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1278 The largest mtrr entry size for a continous block can be set with
1283 config MTRR_SANITIZER_ENABLE_DEFAULT
1284 int "MTRR cleanup enable value (0-1)"
1287 depends on MTRR_SANITIZER
1289 Enable mtrr cleanup default value
1291 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1292 int "MTRR cleanup spare reg num (0-7)"
1295 depends on MTRR_SANITIZER
1297 mtrr cleanup spare entries default, it can be changed via
1298 mtrr_spare_reg_nr=N on the kernel command line.
1302 prompt "x86 PAT support"
1305 Use PAT attributes to setup page level cache control.
1307 PATs are the modern equivalents of MTRRs and are much more
1308 flexible than MTRRs.
1310 Say N here if you see bootup problems (boot crash, boot hang,
1311 spontaneous reboots) or a non-working video driver.
1316 bool "EFI runtime service support"
1319 This enables the kernel to use EFI runtime services that are
1320 available (such as the EFI variable services).
1322 This option is only useful on systems that have EFI firmware.
1323 In addition, you should use the latest ELILO loader available
1324 at <http://elilo.sourceforge.net> in order to take advantage
1325 of EFI runtime services. However, even with this option, the
1326 resultant kernel should continue to boot on existing non-EFI
1331 prompt "Enable seccomp to safely compute untrusted bytecode"
1333 This kernel feature is useful for number crunching applications
1334 that may need to compute untrusted bytecode during their
1335 execution. By using pipes or other transports made available to
1336 the process as file descriptors supporting the read/write
1337 syscalls, it's possible to isolate those applications in
1338 their own address space using seccomp. Once seccomp is
1339 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1340 and the task is only allowed to execute a few safe syscalls
1341 defined by each seccomp mode.
1343 If unsure, say Y. Only embedded should say N here.
1345 config CC_STACKPROTECTOR
1346 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1347 depends on X86_64 && EXPERIMENTAL && BROKEN
1349 This option turns on the -fstack-protector GCC feature. This
1350 feature puts, at the beginning of critical functions, a canary
1351 value on the stack just before the return address, and validates
1352 the value just before actually returning. Stack based buffer
1353 overflows (that need to overwrite this return address) now also
1354 overwrite the canary, which gets detected and the attack is then
1355 neutralized via a kernel panic.
1357 This feature requires gcc version 4.2 or above, or a distribution
1358 gcc with the feature backported. Older versions are automatically
1359 detected and for those versions, this configuration option is ignored.
1361 config CC_STACKPROTECTOR_ALL
1362 bool "Use stack-protector for all functions"
1363 depends on CC_STACKPROTECTOR
1365 Normally, GCC only inserts the canary value protection for
1366 functions that use large-ish on-stack buffers. By enabling
1367 this option, GCC will be asked to do this for ALL functions.
1369 source kernel/Kconfig.hz
1372 bool "kexec system call"
1373 depends on X86_BIOS_REBOOT
1375 kexec is a system call that implements the ability to shutdown your
1376 current kernel, and to start another kernel. It is like a reboot
1377 but it is independent of the system firmware. And like a reboot
1378 you can start any kernel with it, not just Linux.
1380 The name comes from the similarity to the exec system call.
1382 It is an ongoing process to be certain the hardware in a machine
1383 is properly shutdown, so do not be surprised if this code does not
1384 initially work for you. It may help to enable device hotplugging
1385 support. As of this writing the exact hardware interface is
1386 strongly in flux, so no good recommendation can be made.
1389 bool "kernel crash dumps"
1390 depends on X86_64 || (X86_32 && HIGHMEM)
1392 Generate crash dump after being started by kexec.
1393 This should be normally only set in special crash dump kernels
1394 which are loaded in the main kernel with kexec-tools into
1395 a specially reserved region and then later executed after
1396 a crash by kdump/kexec. The crash dump kernel must be compiled
1397 to a memory address not used by the main kernel or BIOS using
1398 PHYSICAL_START, or it must be built as a relocatable image
1399 (CONFIG_RELOCATABLE=y).
1400 For more details see Documentation/kdump/kdump.txt
1403 bool "kexec jump (EXPERIMENTAL)"
1404 depends on EXPERIMENTAL
1405 depends on KEXEC && HIBERNATION && X86_32
1407 Jump between original kernel and kexeced kernel and invoke
1408 code in physical address mode via KEXEC
1410 config PHYSICAL_START
1411 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1412 default "0x1000000" if X86_NUMAQ
1413 default "0x200000" if X86_64
1416 This gives the physical address where the kernel is loaded.
1418 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1419 bzImage will decompress itself to above physical address and
1420 run from there. Otherwise, bzImage will run from the address where
1421 it has been loaded by the boot loader and will ignore above physical
1424 In normal kdump cases one does not have to set/change this option
1425 as now bzImage can be compiled as a completely relocatable image
1426 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1427 address. This option is mainly useful for the folks who don't want
1428 to use a bzImage for capturing the crash dump and want to use a
1429 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1430 to be specifically compiled to run from a specific memory area
1431 (normally a reserved region) and this option comes handy.
1433 So if you are using bzImage for capturing the crash dump, leave
1434 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1435 Otherwise if you plan to use vmlinux for capturing the crash dump
1436 change this value to start of the reserved region (Typically 16MB
1437 0x1000000). In other words, it can be set based on the "X" value as
1438 specified in the "crashkernel=YM@XM" command line boot parameter
1439 passed to the panic-ed kernel. Typically this parameter is set as
1440 crashkernel=64M@16M. Please take a look at
1441 Documentation/kdump/kdump.txt for more details about crash dumps.
1443 Usage of bzImage for capturing the crash dump is recommended as
1444 one does not have to build two kernels. Same kernel can be used
1445 as production kernel and capture kernel. Above option should have
1446 gone away after relocatable bzImage support is introduced. But it
1447 is present because there are users out there who continue to use
1448 vmlinux for dump capture. This option should go away down the
1451 Don't change this unless you know what you are doing.
1454 bool "Build a relocatable kernel (EXPERIMENTAL)"
1455 depends on EXPERIMENTAL
1457 This builds a kernel image that retains relocation information
1458 so it can be loaded someplace besides the default 1MB.
1459 The relocations tend to make the kernel binary about 10% larger,
1460 but are discarded at runtime.
1462 One use is for the kexec on panic case where the recovery kernel
1463 must live at a different physical address than the primary
1466 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1467 it has been loaded at and the compile time physical address
1468 (CONFIG_PHYSICAL_START) is ignored.
1470 config PHYSICAL_ALIGN
1472 prompt "Alignment value to which kernel should be aligned" if X86_32
1473 default "0x100000" if X86_32
1474 default "0x200000" if X86_64
1475 range 0x2000 0x400000
1477 This value puts the alignment restrictions on physical address
1478 where kernel is loaded and run from. Kernel is compiled for an
1479 address which meets above alignment restriction.
1481 If bootloader loads the kernel at a non-aligned address and
1482 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1483 address aligned to above value and run from there.
1485 If bootloader loads the kernel at a non-aligned address and
1486 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1487 load address and decompress itself to the address it has been
1488 compiled for and run from there. The address for which kernel is
1489 compiled already meets above alignment restrictions. Hence the
1490 end result is that kernel runs from a physical address meeting
1491 above alignment restrictions.
1493 Don't change this unless you know what you are doing.
1496 bool "Support for hot-pluggable CPUs"
1497 depends on SMP && HOTPLUG && !X86_VOYAGER
1499 Say Y here to allow turning CPUs off and on. CPUs can be
1500 controlled through /sys/devices/system/cpu.
1501 ( Note: power management support will enable this option
1502 automatically on SMP systems. )
1503 Say N if you want to disable CPU hotplug.
1507 prompt "Compat VDSO support"
1508 depends on X86_32 || IA32_EMULATION
1510 Map the 32-bit VDSO to the predictable old-style address too.
1512 Say N here if you are running a sufficiently recent glibc
1513 version (2.3.3 or later), to remove the high-mapped
1514 VDSO mapping and to exclusively use the randomized VDSO.
1519 bool "Built-in kernel command line"
1522 Allow for specifying boot arguments to the kernel at
1523 build time. On some systems (e.g. embedded ones), it is
1524 necessary or convenient to provide some or all of the
1525 kernel boot arguments with the kernel itself (that is,
1526 to not rely on the boot loader to provide them.)
1528 To compile command line arguments into the kernel,
1529 set this option to 'Y', then fill in the
1530 the boot arguments in CONFIG_CMDLINE.
1532 Systems with fully functional boot loaders (i.e. non-embedded)
1533 should leave this option set to 'N'.
1536 string "Built-in kernel command string"
1537 depends on CMDLINE_BOOL
1540 Enter arguments here that should be compiled into the kernel
1541 image and used at boot time. If the boot loader provides a
1542 command line at boot time, it is appended to this string to
1543 form the full kernel command line, when the system boots.
1545 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1546 change this behavior.
1548 In most cases, the command line (whether built-in or provided
1549 by the boot loader) should specify the device for the root
1552 config CMDLINE_OVERRIDE
1553 bool "Built-in command line overrides boot loader arguments"
1555 depends on CMDLINE_BOOL
1557 Set this option to 'Y' to have the kernel ignore the boot loader
1558 command line, and use ONLY the built-in command line.
1560 This is used to work around broken boot loaders. This should
1561 be set to 'N' under normal conditions.
1565 config ARCH_ENABLE_MEMORY_HOTPLUG
1567 depends on X86_64 || (X86_32 && HIGHMEM)
1569 config ARCH_ENABLE_MEMORY_HOTREMOVE
1571 depends on MEMORY_HOTPLUG
1573 config HAVE_ARCH_EARLY_PFN_TO_NID
1577 menu "Power management and ACPI options"
1578 depends on !X86_VOYAGER
1580 config ARCH_HIBERNATION_HEADER
1582 depends on X86_64 && HIBERNATION
1584 source "kernel/power/Kconfig"
1586 source "drivers/acpi/Kconfig"
1591 depends on APM || APM_MODULE
1594 tristate "APM (Advanced Power Management) BIOS support"
1595 depends on X86_32 && PM_SLEEP
1597 APM is a BIOS specification for saving power using several different
1598 techniques. This is mostly useful for battery powered laptops with
1599 APM compliant BIOSes. If you say Y here, the system time will be
1600 reset after a RESUME operation, the /proc/apm device will provide
1601 battery status information, and user-space programs will receive
1602 notification of APM "events" (e.g. battery status change).
1604 If you select "Y" here, you can disable actual use of the APM
1605 BIOS by passing the "apm=off" option to the kernel at boot time.
1607 Note that the APM support is almost completely disabled for
1608 machines with more than one CPU.
1610 In order to use APM, you will need supporting software. For location
1611 and more information, read <file:Documentation/power/pm.txt> and the
1612 Battery Powered Linux mini-HOWTO, available from
1613 <http://www.tldp.org/docs.html#howto>.
1615 This driver does not spin down disk drives (see the hdparm(8)
1616 manpage ("man 8 hdparm") for that), and it doesn't turn off
1617 VESA-compliant "green" monitors.
1619 This driver does not support the TI 4000M TravelMate and the ACER
1620 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1621 desktop machines also don't have compliant BIOSes, and this driver
1622 may cause those machines to panic during the boot phase.
1624 Generally, if you don't have a battery in your machine, there isn't
1625 much point in using this driver and you should say N. If you get
1626 random kernel OOPSes or reboots that don't seem to be related to
1627 anything, try disabling/enabling this option (or disabling/enabling
1630 Some other things you should try when experiencing seemingly random,
1633 1) make sure that you have enough swap space and that it is
1635 2) pass the "no-hlt" option to the kernel
1636 3) switch on floating point emulation in the kernel and pass
1637 the "no387" option to the kernel
1638 4) pass the "floppy=nodma" option to the kernel
1639 5) pass the "mem=4M" option to the kernel (thereby disabling
1640 all but the first 4 MB of RAM)
1641 6) make sure that the CPU is not over clocked.
1642 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1643 8) disable the cache from your BIOS settings
1644 9) install a fan for the video card or exchange video RAM
1645 10) install a better fan for the CPU
1646 11) exchange RAM chips
1647 12) exchange the motherboard.
1649 To compile this driver as a module, choose M here: the
1650 module will be called apm.
1654 config APM_IGNORE_USER_SUSPEND
1655 bool "Ignore USER SUSPEND"
1657 This option will ignore USER SUSPEND requests. On machines with a
1658 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1659 series notebooks, it is necessary to say Y because of a BIOS bug.
1661 config APM_DO_ENABLE
1662 bool "Enable PM at boot time"
1664 Enable APM features at boot time. From page 36 of the APM BIOS
1665 specification: "When disabled, the APM BIOS does not automatically
1666 power manage devices, enter the Standby State, enter the Suspend
1667 State, or take power saving steps in response to CPU Idle calls."
1668 This driver will make CPU Idle calls when Linux is idle (unless this
1669 feature is turned off -- see "Do CPU IDLE calls", below). This
1670 should always save battery power, but more complicated APM features
1671 will be dependent on your BIOS implementation. You may need to turn
1672 this option off if your computer hangs at boot time when using APM
1673 support, or if it beeps continuously instead of suspending. Turn
1674 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1675 T400CDT. This is off by default since most machines do fine without
1679 bool "Make CPU Idle calls when idle"
1681 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1682 On some machines, this can activate improved power savings, such as
1683 a slowed CPU clock rate, when the machine is idle. These idle calls
1684 are made after the idle loop has run for some length of time (e.g.,
1685 333 mS). On some machines, this will cause a hang at boot time or
1686 whenever the CPU becomes idle. (On machines with more than one CPU,
1687 this option does nothing.)
1689 config APM_DISPLAY_BLANK
1690 bool "Enable console blanking using APM"
1692 Enable console blanking using the APM. Some laptops can use this to
1693 turn off the LCD backlight when the screen blanker of the Linux
1694 virtual console blanks the screen. Note that this is only used by
1695 the virtual console screen blanker, and won't turn off the backlight
1696 when using the X Window system. This also doesn't have anything to
1697 do with your VESA-compliant power-saving monitor. Further, this
1698 option doesn't work for all laptops -- it might not turn off your
1699 backlight at all, or it might print a lot of errors to the console,
1700 especially if you are using gpm.
1702 config APM_ALLOW_INTS
1703 bool "Allow interrupts during APM BIOS calls"
1705 Normally we disable external interrupts while we are making calls to
1706 the APM BIOS as a measure to lessen the effects of a badly behaving
1707 BIOS implementation. The BIOS should reenable interrupts if it
1708 needs to. Unfortunately, some BIOSes do not -- especially those in
1709 many of the newer IBM Thinkpads. If you experience hangs when you
1710 suspend, try setting this to Y. Otherwise, say N.
1714 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1716 source "drivers/cpuidle/Kconfig"
1718 source "drivers/idle/Kconfig"
1723 menu "Bus options (PCI etc.)"
1728 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1730 Find out whether you have a PCI motherboard. PCI is the name of a
1731 bus system, i.e. the way the CPU talks to the other stuff inside
1732 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1733 VESA. If you have PCI, say Y, otherwise N.
1736 prompt "PCI access mode"
1737 depends on X86_32 && PCI
1740 On PCI systems, the BIOS can be used to detect the PCI devices and
1741 determine their configuration. However, some old PCI motherboards
1742 have BIOS bugs and may crash if this is done. Also, some embedded
1743 PCI-based systems don't have any BIOS at all. Linux can also try to
1744 detect the PCI hardware directly without using the BIOS.
1746 With this option, you can specify how Linux should detect the
1747 PCI devices. If you choose "BIOS", the BIOS will be used,
1748 if you choose "Direct", the BIOS won't be used, and if you
1749 choose "MMConfig", then PCI Express MMCONFIG will be used.
1750 If you choose "Any", the kernel will try MMCONFIG, then the
1751 direct access method and falls back to the BIOS if that doesn't
1752 work. If unsure, go with the default, which is "Any".
1757 config PCI_GOMMCONFIG
1774 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1776 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1779 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1783 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1787 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1794 bool "Support mmconfig PCI config space access"
1795 depends on X86_64 && PCI && ACPI
1798 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1799 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1801 DMA remapping (DMAR) devices support enables independent address
1802 translations for Direct Memory Access (DMA) from devices.
1803 These DMA remapping devices are reported via ACPI tables
1804 and include PCI device scope covered by these DMA
1809 prompt "Support for Graphics workaround"
1812 Current Graphics drivers tend to use physical address
1813 for DMA and avoid using DMA APIs. Setting this config
1814 option permits the IOMMU driver to set a unity map for
1815 all the OS-visible memory. Hence the driver can continue
1816 to use physical addresses for DMA.
1818 config DMAR_FLOPPY_WA
1822 Floppy disk drivers are know to bypass DMA API calls
1823 thereby failing to work when IOMMU is enabled. This
1824 workaround will setup a 1:1 mapping for the first
1825 16M to make floppy (an ISA device) work.
1828 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1829 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1831 Supports Interrupt remapping for IO-APIC and MSI devices.
1832 To use x2apic mode in the CPU's which support x2APIC enhancements or
1833 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1835 source "drivers/pci/pcie/Kconfig"
1837 source "drivers/pci/Kconfig"
1839 # x86_64 have no ISA slots, but do have ISA-style DMA.
1847 depends on !X86_VOYAGER
1849 Find out whether you have ISA slots on your motherboard. ISA is the
1850 name of a bus system, i.e. the way the CPU talks to the other stuff
1851 inside your box. Other bus systems are PCI, EISA, MicroChannel
1852 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1853 newer boards don't support it. If you have ISA, say Y, otherwise N.
1859 The Extended Industry Standard Architecture (EISA) bus was
1860 developed as an open alternative to the IBM MicroChannel bus.
1862 The EISA bus provided some of the features of the IBM MicroChannel
1863 bus while maintaining backward compatibility with cards made for
1864 the older ISA bus. The EISA bus saw limited use between 1988 and
1865 1995 when it was made obsolete by the PCI bus.
1867 Say Y here if you are building a kernel for an EISA-based machine.
1871 source "drivers/eisa/Kconfig"
1874 bool "MCA support" if !X86_VOYAGER
1875 default y if X86_VOYAGER
1877 MicroChannel Architecture is found in some IBM PS/2 machines and
1878 laptops. It is a bus system similar to PCI or ISA. See
1879 <file:Documentation/mca.txt> (and especially the web page given
1880 there) before attempting to build an MCA bus kernel.
1882 source "drivers/mca/Kconfig"
1885 tristate "NatSemi SCx200 support"
1886 depends on !X86_VOYAGER
1888 This provides basic support for National Semiconductor's
1889 (now AMD's) Geode processors. The driver probes for the
1890 PCI-IDs of several on-chip devices, so its a good dependency
1891 for other scx200_* drivers.
1893 If compiled as a module, the driver is named scx200.
1895 config SCx200HR_TIMER
1896 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1897 depends on SCx200 && GENERIC_TIME
1900 This driver provides a clocksource built upon the on-chip
1901 27MHz high-resolution timer. Its also a workaround for
1902 NSC Geode SC-1100's buggy TSC, which loses time when the
1903 processor goes idle (as is done by the scheduler). The
1904 other workaround is idle=poll boot option.
1906 config GEODE_MFGPT_TIMER
1908 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1909 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1911 This driver provides a clock event source based on the MFGPT
1912 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1913 MFGPTs have a better resolution and max interval than the
1914 generic PIT, and are suitable for use as high-res timers.
1917 bool "One Laptop Per Child support"
1920 Add support for detecting the unique features of the OLPC
1927 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1929 source "drivers/pcmcia/Kconfig"
1931 source "drivers/pci/hotplug/Kconfig"
1936 menu "Executable file formats / Emulations"
1938 source "fs/Kconfig.binfmt"
1940 config IA32_EMULATION
1941 bool "IA32 Emulation"
1943 select COMPAT_BINFMT_ELF
1945 Include code to run 32-bit programs under a 64-bit kernel. You should
1946 likely turn this on, unless you're 100% sure that you don't have any
1947 32-bit programs left.
1950 tristate "IA32 a.out support"
1951 depends on IA32_EMULATION
1953 Support old a.out binaries in the 32bit emulation.
1957 depends on IA32_EMULATION
1959 config COMPAT_FOR_U64_ALIGNMENT
1963 config SYSVIPC_COMPAT
1965 depends on COMPAT && SYSVIPC
1970 config HAVE_ATOMIC_IOMAP
1974 source "net/Kconfig"
1976 source "drivers/Kconfig"
1978 source "drivers/firmware/Kconfig"
1982 source "arch/x86/Kconfig.debug"
1984 source "security/Kconfig"
1986 source "crypto/Kconfig"
1988 source "arch/x86/kvm/Kconfig"
1990 source "lib/Kconfig"
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