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
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
144 config ARCH_SUSPEND_POSSIBLE
151 config ARCH_POPULATES_NODE_MAP
158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
161 # Use the generic interrupt handling code in kernel/irq/:
162 config GENERIC_HARDIRQS
166 config GENERIC_IRQ_PROBE
170 config GENERIC_PENDING_IRQ
172 depends on GENERIC_HARDIRQS && SMP
175 config USE_GENERIC_SMP_HELPERS
181 depends on X86_32 && SMP
185 depends on X86_64 && SMP
192 config X86_TRAMPOLINE
194 depends on SMP || (64BIT && ACPI_SLEEP)
197 config X86_32_LAZY_GS
199 depends on X86_32 && !CC_STACKPROTECTOR
203 source "init/Kconfig"
204 source "kernel/Kconfig.freezer"
206 menu "Processor type and features"
208 source "kernel/time/Kconfig"
211 bool "Symmetric multi-processing support"
213 This enables support for systems with more than one CPU. If you have
214 a system with only one CPU, like most personal computers, say N. If
215 you have a system with more than one CPU, say Y.
217 If you say N here, the kernel will run on single and multiprocessor
218 machines, but will use only one CPU of a multiprocessor machine. If
219 you say Y here, the kernel will run on many, but not all,
220 singleprocessor machines. On a singleprocessor machine, the kernel
221 will run faster if you say N here.
223 Note that if you say Y here and choose architecture "586" or
224 "Pentium" under "Processor family", the kernel will not work on 486
225 architectures. Similarly, multiprocessor kernels for the "PPro"
226 architecture may not work on all Pentium based boards.
228 People using multiprocessor machines who say Y here should also say
229 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
230 Management" code will be disabled if you say Y here.
232 See also <file:Documentation/i386/IO-APIC.txt>,
233 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
234 <http://www.tldp.org/docs.html#howto>.
236 If you don't know what to do here, say N.
239 bool "Support x2apic"
240 depends on X86_LOCAL_APIC && X86_64
242 This enables x2apic support on CPUs that have this feature.
244 This allows 32-bit apic IDs (so it can support very large systems),
245 and accesses the local apic via MSRs not via mmio.
247 ( On certain CPU models you may need to enable INTR_REMAP too,
248 to get functional x2apic mode. )
250 If you don't know what to do here, say N.
253 bool "Support sparse irq numbering"
254 depends on PCI_MSI || HT_IRQ
256 This enables support for sparse irqs. This is useful for distro
257 kernels that want to define a high CONFIG_NR_CPUS value but still
258 want to have low kernel memory footprint on smaller machines.
260 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
261 out the irq_desc[] array in a more NUMA-friendly way. )
263 If you don't know what to do here, say N.
265 config NUMA_MIGRATE_IRQ_DESC
266 bool "Move irq desc when changing irq smp_affinity"
267 depends on SPARSE_IRQ && NUMA
270 This enables moving irq_desc to cpu/node that irq will use handled.
272 If you don't know what to do here, say N.
275 bool "Enable MPS table" if ACPI
277 depends on X86_LOCAL_APIC
279 For old smp systems that do not have proper acpi support. Newer systems
280 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
283 bool "Support for big SMP systems with more than 8 CPUs"
284 depends on X86_32 && SMP
286 This option is needed for the systems that have more than 8 CPUs
288 config X86_EXTENDED_PLATFORM
289 bool "Support for extended (non-PC) x86 platforms"
292 If you disable this option then the kernel will only support
293 standard PC platforms. (which covers the vast majority of
296 If you enable this option then you'll be able to select a number
297 of non-PC x86 platforms.
299 If you have one of these systems, or if you want to build a
300 generic distribution kernel, say Y here - otherwise say N.
302 # This is an alphabetically sorted list of 64 bit extended platforms
303 # Please maintain the alphabetic order if and when there are additions
308 depends on X86_64 && PCI
309 depends on X86_EXTENDED_PLATFORM
311 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
312 supposed to run on these EM64T-based machines. Only choose this option
313 if you have one of these machines.
316 bool "SGI Ultraviolet"
318 depends on X86_EXTENDED_PLATFORM
321 This option is needed in order to support SGI Ultraviolet systems.
322 If you don't have one of these, you should say N here.
324 # Following is an alphabetically sorted list of 32 bit extended platforms
325 # Please maintain the alphabetic order if and when there are additions
330 depends on X86_EXTENDED_PLATFORM
332 Select this for an AMD Elan processor.
334 Do not use this option for K6/Athlon/Opteron processors!
336 If unsure, choose "PC-compatible" instead.
339 bool "RDC R-321x SoC"
341 depends on X86_EXTENDED_PLATFORM
343 select X86_REBOOTFIXUPS
345 This option is needed for RDC R-321x system-on-chip, also known
347 If you don't have one of these chips, you should say N here.
349 config X86_32_NON_STANDARD
350 bool "Support non-standard 32-bit SMP architectures"
351 depends on X86_32 && SMP
352 depends on X86_EXTENDED_PLATFORM
354 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
355 subarchitectures. It is intended for a generic binary kernel.
356 if you select them all, kernel will probe it one by one. and will
359 # Alphabetically sorted list of Non standard 32 bit platforms
362 bool "NUMAQ (IBM/Sequent)"
363 depends on X86_32_NON_STANDARD
367 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
368 NUMA multiquad box. This changes the way that processors are
369 bootstrapped, and uses Clustered Logical APIC addressing mode instead
370 of Flat Logical. You will need a new lynxer.elf file to flash your
371 firmware with - send email to <Martin.Bligh@us.ibm.com>.
374 bool "SGI 320/540 (Visual Workstation)"
375 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
376 depends on X86_32_NON_STANDARD
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 "Summit/EXA (IBM x440)"
388 depends on X86_32_NON_STANDARD
390 This option is needed for IBM systems that use the Summit/EXA chipset.
391 In particular, it is needed for the x440.
394 bool "Unisys ES7000 IA32 series"
395 depends on X86_32_NON_STANDARD && X86_BIGSMP
397 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
398 supposed to run on an IA32-based Unisys ES7000 system.
402 depends on SMP && !PCI && BROKEN
403 depends on X86_32_NON_STANDARD
405 Voyager is an MCA-based 32-way capable SMP architecture proprietary
406 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
410 If you do not specifically know you have a Voyager based machine,
411 say N here, otherwise the kernel you build will not be bootable.
413 config SCHED_OMIT_FRAME_POINTER
415 prompt "Single-depth WCHAN output"
418 Calculate simpler /proc/<PID>/wchan values. If this option
419 is disabled then wchan values will recurse back to the
420 caller function. This provides more accurate wchan values,
421 at the expense of slightly more scheduling overhead.
423 If in doubt, say "Y".
425 menuconfig PARAVIRT_GUEST
426 bool "Paravirtualized guest support"
428 Say Y here to get to see options related to running Linux under
429 various hypervisors. This option alone does not add any kernel code.
431 If you say N, all options in this submenu will be skipped and disabled.
435 source "arch/x86/xen/Kconfig"
438 bool "VMI Guest support"
442 VMI provides a paravirtualized interface to the VMware ESX server
443 (it could be used by other hypervisors in theory too, but is not
444 at the moment), by linking the kernel to a GPL-ed ROM module
445 provided by the hypervisor.
448 bool "KVM paravirtualized clock"
450 select PARAVIRT_CLOCK
452 Turning on this option will allow you to run a paravirtualized clock
453 when running over the KVM hypervisor. Instead of relying on a PIT
454 (or probably other) emulation by the underlying device model, the host
455 provides the guest with timing infrastructure such as time of day, and
459 bool "KVM Guest support"
462 This option enables various optimizations for running under the KVM
465 source "arch/x86/lguest/Kconfig"
468 bool "Enable paravirtualization code"
470 This changes the kernel so it can modify itself when it is run
471 under a hypervisor, potentially improving performance significantly
472 over full virtualization. However, when run without a hypervisor
473 the kernel is theoretically slower and slightly larger.
475 config PARAVIRT_CLOCK
481 config PARAVIRT_DEBUG
482 bool "paravirt-ops debugging"
483 depends on PARAVIRT && DEBUG_KERNEL
485 Enable to debug paravirt_ops internals. Specifically, BUG if
486 a paravirt_op is missing when it is called.
491 This option adds a kernel parameter 'memtest', which allows memtest
493 memtest=0, mean disabled; -- default
494 memtest=1, mean do 1 test pattern;
496 memtest=4, mean do 4 test patterns.
497 If you are unsure how to answer this question, answer N.
499 config X86_SUMMIT_NUMA
501 depends on X86_32 && NUMA && X86_32_NON_STANDARD
503 config X86_CYCLONE_TIMER
505 depends on X86_32_NON_STANDARD
507 source "arch/x86/Kconfig.cpu"
511 prompt "HPET Timer Support" if X86_32
513 Use the IA-PC HPET (High Precision Event Timer) to manage
514 time in preference to the PIT and RTC, if a HPET is
516 HPET is the next generation timer replacing legacy 8254s.
517 The HPET provides a stable time base on SMP
518 systems, unlike the TSC, but it is more expensive to access,
519 as it is off-chip. You can find the HPET spec at
520 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
522 You can safely choose Y here. However, HPET will only be
523 activated if the platform and the BIOS support this feature.
524 Otherwise the 8254 will be used for timing services.
526 Choose N to continue using the legacy 8254 timer.
528 config HPET_EMULATE_RTC
530 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
532 # Mark as embedded because too many people got it wrong.
533 # The code disables itself when not needed.
536 bool "Enable DMI scanning" if EMBEDDED
538 Enabled scanning of DMI to identify machine quirks. Say Y
539 here unless you have verified that your setup is not
540 affected by entries in the DMI blacklist. Required by PNP
544 bool "GART IOMMU support" if EMBEDDED
548 depends on X86_64 && PCI
550 Support for full DMA access of devices with 32bit memory access only
551 on systems with more than 3GB. This is usually needed for USB,
552 sound, many IDE/SATA chipsets and some other devices.
553 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
554 based hardware IOMMU and a software bounce buffer based IOMMU used
555 on Intel systems and as fallback.
556 The code is only active when needed (enough memory and limited
557 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
561 bool "IBM Calgary IOMMU support"
563 depends on X86_64 && PCI && EXPERIMENTAL
565 Support for hardware IOMMUs in IBM's xSeries x366 and x460
566 systems. Needed to run systems with more than 3GB of memory
567 properly with 32-bit PCI devices that do not support DAC
568 (Double Address Cycle). Calgary also supports bus level
569 isolation, where all DMAs pass through the IOMMU. This
570 prevents them from going anywhere except their intended
571 destination. This catches hard-to-find kernel bugs and
572 mis-behaving drivers and devices that do not use the DMA-API
573 properly to set up their DMA buffers. The IOMMU can be
574 turned off at boot time with the iommu=off parameter.
575 Normally the kernel will make the right choice by itself.
578 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
580 prompt "Should Calgary be enabled by default?"
581 depends on CALGARY_IOMMU
583 Should Calgary be enabled by default? if you choose 'y', Calgary
584 will be used (if it exists). If you choose 'n', Calgary will not be
585 used even if it exists. If you choose 'n' and would like to use
586 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
590 bool "AMD IOMMU support"
593 depends on X86_64 && PCI && ACPI
595 With this option you can enable support for AMD IOMMU hardware in
596 your system. An IOMMU is a hardware component which provides
597 remapping of DMA memory accesses from devices. With an AMD IOMMU you
598 can isolate the the DMA memory of different devices and protect the
599 system from misbehaving device drivers or hardware.
601 You can find out if your system has an AMD IOMMU if you look into
602 your BIOS for an option to enable it or if you have an IVRS ACPI
605 config AMD_IOMMU_STATS
606 bool "Export AMD IOMMU statistics to debugfs"
610 This option enables code in the AMD IOMMU driver to collect various
611 statistics about whats happening in the driver and exports that
612 information to userspace via debugfs.
615 # need this always selected by IOMMU for the VIA workaround
619 Support for software bounce buffers used on x86-64 systems
620 which don't have a hardware IOMMU (e.g. the current generation
621 of Intel's x86-64 CPUs). Using this PCI devices which can only
622 access 32-bits of memory can be used on systems with more than
623 3 GB of memory. If unsure, say Y.
626 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
629 def_bool (AMD_IOMMU || DMAR)
632 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
633 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
634 select CPUMASK_OFFSTACK
637 Configure maximum number of CPUS and NUMA Nodes for this architecture.
641 int "Maximum number of CPUs" if SMP && !MAXSMP
642 range 2 512 if SMP && !MAXSMP
644 default "4096" if MAXSMP
645 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
648 This allows you to specify the maximum number of CPUs which this
649 kernel will support. The maximum supported value is 512 and the
650 minimum value which makes sense is 2.
652 This is purely to save memory - each supported CPU adds
653 approximately eight kilobytes to the kernel image.
656 bool "SMT (Hyperthreading) scheduler support"
659 SMT scheduler support improves the CPU scheduler's decision making
660 when dealing with Intel Pentium 4 chips with HyperThreading at a
661 cost of slightly increased overhead in some places. If unsure say
666 prompt "Multi-core scheduler support"
669 Multi-core scheduler support improves the CPU scheduler's decision
670 making when dealing with multi-core CPU chips at a cost of slightly
671 increased overhead in some places. If unsure say N here.
673 source "kernel/Kconfig.preempt"
676 bool "Local APIC support on uniprocessors"
677 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
679 A local APIC (Advanced Programmable Interrupt Controller) is an
680 integrated interrupt controller in the CPU. If you have a single-CPU
681 system which has a processor with a local APIC, you can say Y here to
682 enable and use it. If you say Y here even though your machine doesn't
683 have a local APIC, then the kernel will still run with no slowdown at
684 all. The local APIC supports CPU-generated self-interrupts (timer,
685 performance counters), and the NMI watchdog which detects hard
689 bool "IO-APIC support on uniprocessors"
690 depends on X86_UP_APIC
692 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
693 SMP-capable replacement for PC-style interrupt controllers. Most
694 SMP systems and many recent uniprocessor systems have one.
696 If you have a single-CPU system with an IO-APIC, you can say Y here
697 to use it. If you say Y here even though your machine doesn't have
698 an IO-APIC, then the kernel will still run with no slowdown at all.
700 config X86_LOCAL_APIC
702 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
706 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
708 config X86_VISWS_APIC
710 depends on X86_32 && X86_VISWS
712 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
713 bool "Reroute for broken boot IRQs"
715 depends on X86_IO_APIC
717 This option enables a workaround that fixes a source of
718 spurious interrupts. This is recommended when threaded
719 interrupt handling is used on systems where the generation of
720 superfluous "boot interrupts" cannot be disabled.
722 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
723 entry in the chipset's IO-APIC is masked (as, e.g. the RT
724 kernel does during interrupt handling). On chipsets where this
725 boot IRQ generation cannot be disabled, this workaround keeps
726 the original IRQ line masked so that only the equivalent "boot
727 IRQ" is delivered to the CPUs. The workaround also tells the
728 kernel to set up the IRQ handler on the boot IRQ line. In this
729 way only one interrupt is delivered to the kernel. Otherwise
730 the spurious second interrupt may cause the kernel to bring
731 down (vital) interrupt lines.
733 Only affects "broken" chipsets. Interrupt sharing may be
734 increased on these systems.
737 bool "Machine Check Exception"
739 Machine Check Exception support allows the processor to notify the
740 kernel if it detects a problem (e.g. overheating, component failure).
741 The action the kernel takes depends on the severity of the problem,
742 ranging from a warning message on the console, to halting the machine.
743 Your processor must be a Pentium or newer to support this - check the
744 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
745 have a design flaw which leads to false MCE events - hence MCE is
746 disabled on all P5 processors, unless explicitly enabled with "mce"
747 as a boot argument. Similarly, if MCE is built in and creates a
748 problem on some new non-standard machine, you can boot with "nomce"
749 to disable it. MCE support simply ignores non-MCE processors like
750 the 386 and 486, so nearly everyone can say Y here.
754 prompt "Intel MCE features"
755 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
757 Additional support for intel specific MCE features such as
762 prompt "AMD MCE features"
763 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
765 Additional support for AMD specific MCE features such as
766 the DRAM Error Threshold.
768 config X86_MCE_NONFATAL
769 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
770 depends on X86_32 && X86_MCE
772 Enabling this feature starts a timer that triggers every 5 seconds which
773 will look at the machine check registers to see if anything happened.
774 Non-fatal problems automatically get corrected (but still logged).
775 Disable this if you don't want to see these messages.
776 Seeing the messages this option prints out may be indicative of dying
777 or out-of-spec (ie, overclocked) hardware.
778 This option only does something on certain CPUs.
779 (AMD Athlon/Duron and Intel Pentium 4)
781 config X86_MCE_P4THERMAL
782 bool "check for P4 thermal throttling interrupt."
783 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
785 Enabling this feature will cause a message to be printed when the P4
786 enters thermal throttling.
789 bool "Enable VM86 support" if EMBEDDED
793 This option is required by programs like DOSEMU to run 16-bit legacy
794 code on X86 processors. It also may be needed by software like
795 XFree86 to initialize some video cards via BIOS. Disabling this
796 option saves about 6k.
799 tristate "Toshiba Laptop support"
802 This adds a driver to safely access the System Management Mode of
803 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
804 not work on models with a Phoenix BIOS. The System Management Mode
805 is used to set the BIOS and power saving options on Toshiba portables.
807 For information on utilities to make use of this driver see the
808 Toshiba Linux utilities web site at:
809 <http://www.buzzard.org.uk/toshiba/>.
811 Say Y if you intend to run this kernel on a Toshiba portable.
815 tristate "Dell laptop support"
817 This adds a driver to safely access the System Management Mode
818 of the CPU on the Dell Inspiron 8000. The System Management Mode
819 is used to read cpu temperature and cooling fan status and to
820 control the fans on the I8K portables.
822 This driver has been tested only on the Inspiron 8000 but it may
823 also work with other Dell laptops. You can force loading on other
824 models by passing the parameter `force=1' to the module. Use at
827 For information on utilities to make use of this driver see the
828 I8K Linux utilities web site at:
829 <http://people.debian.org/~dz/i8k/>
831 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
834 config X86_REBOOTFIXUPS
835 bool "Enable X86 board specific fixups for reboot"
838 This enables chipset and/or board specific fixups to be done
839 in order to get reboot to work correctly. This is only needed on
840 some combinations of hardware and BIOS. The symptom, for which
841 this config is intended, is when reboot ends with a stalled/hung
844 Currently, the only fixup is for the Geode machines using
845 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
847 Say Y if you want to enable the fixup. Currently, it's safe to
848 enable this option even if you don't need it.
852 tristate "/dev/cpu/microcode - microcode support"
855 If you say Y here, you will be able to update the microcode on
856 certain Intel and AMD processors. The Intel support is for the
857 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
858 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
859 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
860 You will obviously need the actual microcode binary data itself
861 which is not shipped with the Linux kernel.
863 This option selects the general module only, you need to select
864 at least one vendor specific module as well.
866 To compile this driver as a module, choose M here: the
867 module will be called microcode.
869 config MICROCODE_INTEL
870 bool "Intel microcode patch loading support"
875 This options enables microcode patch loading support for Intel
878 For latest news and information on obtaining all the required
879 Intel ingredients for this driver, check:
880 <http://www.urbanmyth.org/microcode/>.
883 bool "AMD microcode patch loading support"
887 If you select this option, microcode patch loading support for AMD
888 processors will be enabled.
890 config MICROCODE_OLD_INTERFACE
895 tristate "/dev/cpu/*/msr - Model-specific register support"
897 This device gives privileged processes access to the x86
898 Model-Specific Registers (MSRs). It is a character device with
899 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
900 MSR accesses are directed to a specific CPU on multi-processor
904 tristate "/dev/cpu/*/cpuid - CPU information support"
906 This device gives processes access to the x86 CPUID instruction to
907 be executed on a specific processor. It is a character device
908 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
912 prompt "High Memory Support"
913 default HIGHMEM4G if !X86_NUMAQ
914 default HIGHMEM64G if X86_NUMAQ
919 depends on !X86_NUMAQ
921 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
922 However, the address space of 32-bit x86 processors is only 4
923 Gigabytes large. That means that, if you have a large amount of
924 physical memory, not all of it can be "permanently mapped" by the
925 kernel. The physical memory that's not permanently mapped is called
928 If you are compiling a kernel which will never run on a machine with
929 more than 1 Gigabyte total physical RAM, answer "off" here (default
930 choice and suitable for most users). This will result in a "3GB/1GB"
931 split: 3GB are mapped so that each process sees a 3GB virtual memory
932 space and the remaining part of the 4GB virtual memory space is used
933 by the kernel to permanently map as much physical memory as
936 If the machine has between 1 and 4 Gigabytes physical RAM, then
939 If more than 4 Gigabytes is used then answer "64GB" here. This
940 selection turns Intel PAE (Physical Address Extension) mode on.
941 PAE implements 3-level paging on IA32 processors. PAE is fully
942 supported by Linux, PAE mode is implemented on all recent Intel
943 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
944 then the kernel will not boot on CPUs that don't support PAE!
946 The actual amount of total physical memory will either be
947 auto detected or can be forced by using a kernel command line option
948 such as "mem=256M". (Try "man bootparam" or see the documentation of
949 your boot loader (lilo or loadlin) about how to pass options to the
950 kernel at boot time.)
952 If unsure, say "off".
956 depends on !X86_NUMAQ
958 Select this if you have a 32-bit processor and between 1 and 4
959 gigabytes of physical RAM.
963 depends on !M386 && !M486
966 Select this if you have a 32-bit processor and more than 4
967 gigabytes of physical RAM.
972 depends on EXPERIMENTAL
973 prompt "Memory split" if EMBEDDED
977 Select the desired split between kernel and user memory.
979 If the address range available to the kernel is less than the
980 physical memory installed, the remaining memory will be available
981 as "high memory". Accessing high memory is a little more costly
982 than low memory, as it needs to be mapped into the kernel first.
983 Note that increasing the kernel address space limits the range
984 available to user programs, making the address space there
985 tighter. Selecting anything other than the default 3G/1G split
986 will also likely make your kernel incompatible with binary-only
989 If you are not absolutely sure what you are doing, leave this
993 bool "3G/1G user/kernel split"
994 config VMSPLIT_3G_OPT
996 bool "3G/1G user/kernel split (for full 1G low memory)"
998 bool "2G/2G user/kernel split"
999 config VMSPLIT_2G_OPT
1001 bool "2G/2G user/kernel split (for full 2G low memory)"
1003 bool "1G/3G user/kernel split"
1008 default 0xB0000000 if VMSPLIT_3G_OPT
1009 default 0x80000000 if VMSPLIT_2G
1010 default 0x78000000 if VMSPLIT_2G_OPT
1011 default 0x40000000 if VMSPLIT_1G
1017 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1020 bool "PAE (Physical Address Extension) Support"
1021 depends on X86_32 && !HIGHMEM4G
1023 PAE is required for NX support, and furthermore enables
1024 larger swapspace support for non-overcommit purposes. It
1025 has the cost of more pagetable lookup overhead, and also
1026 consumes more pagetable space per process.
1028 config ARCH_PHYS_ADDR_T_64BIT
1029 def_bool X86_64 || X86_PAE
1031 config DIRECT_GBPAGES
1032 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1036 Allow the kernel linear mapping to use 1GB pages on CPUs that
1037 support it. This can improve the kernel's performance a tiny bit by
1038 reducing TLB pressure. If in doubt, say "Y".
1040 # Common NUMA Features
1042 bool "Numa Memory Allocation and Scheduler Support"
1044 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1045 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1047 Enable NUMA (Non Uniform Memory Access) support.
1049 The kernel will try to allocate memory used by a CPU on the
1050 local memory controller of the CPU and add some more
1051 NUMA awareness to the kernel.
1053 For 64-bit this is recommended if the system is Intel Core i7
1054 (or later), AMD Opteron, or EM64T NUMA.
1056 For 32-bit this is only needed on (rare) 32-bit-only platforms
1057 that support NUMA topologies, such as NUMAQ / Summit, or if you
1058 boot a 32-bit kernel on a 64-bit NUMA platform.
1060 Otherwise, you should say N.
1062 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1063 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1067 prompt "Old style AMD Opteron NUMA detection"
1068 depends on X86_64 && NUMA && PCI
1070 Enable K8 NUMA node topology detection. You should say Y here if
1071 you have a multi processor AMD K8 system. This uses an old
1072 method to read the NUMA configuration directly from the builtin
1073 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1074 instead, which also takes priority if both are compiled in.
1076 config X86_64_ACPI_NUMA
1078 prompt "ACPI NUMA detection"
1079 depends on X86_64 && NUMA && ACPI && PCI
1082 Enable ACPI SRAT based node topology detection.
1084 # Some NUMA nodes have memory ranges that span
1085 # other nodes. Even though a pfn is valid and
1086 # between a node's start and end pfns, it may not
1087 # reside on that node. See memmap_init_zone()
1089 config NODES_SPAN_OTHER_NODES
1091 depends on X86_64_ACPI_NUMA
1094 bool "NUMA emulation"
1095 depends on X86_64 && NUMA
1097 Enable NUMA emulation. A flat machine will be split
1098 into virtual nodes when booted with "numa=fake=N", where N is the
1099 number of nodes. This is only useful for debugging.
1102 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1104 default "9" if MAXSMP
1105 default "6" if X86_64
1106 default "4" if X86_NUMAQ
1108 depends on NEED_MULTIPLE_NODES
1110 Specify the maximum number of NUMA Nodes available on the target
1111 system. Increases memory reserved to accomodate various tables.
1113 config HAVE_ARCH_BOOTMEM_NODE
1115 depends on X86_32 && NUMA
1117 config ARCH_HAVE_MEMORY_PRESENT
1119 depends on X86_32 && DISCONTIGMEM
1121 config NEED_NODE_MEMMAP_SIZE
1123 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1125 config HAVE_ARCH_ALLOC_REMAP
1127 depends on X86_32 && NUMA
1129 config ARCH_FLATMEM_ENABLE
1131 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1133 config ARCH_DISCONTIGMEM_ENABLE
1135 depends on NUMA && X86_32
1137 config ARCH_DISCONTIGMEM_DEFAULT
1139 depends on NUMA && X86_32
1141 config ARCH_SPARSEMEM_DEFAULT
1145 config ARCH_SPARSEMEM_ENABLE
1147 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1148 select SPARSEMEM_STATIC if X86_32
1149 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1151 config ARCH_SELECT_MEMORY_MODEL
1153 depends on ARCH_SPARSEMEM_ENABLE
1155 config ARCH_MEMORY_PROBE
1157 depends on MEMORY_HOTPLUG
1162 bool "Allocate 3rd-level pagetables from highmem"
1163 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1165 The VM uses one page table entry for each page of physical memory.
1166 For systems with a lot of RAM, this can be wasteful of precious
1167 low memory. Setting this option will put user-space page table
1168 entries in high memory.
1170 config X86_CHECK_BIOS_CORRUPTION
1171 bool "Check for low memory corruption"
1173 Periodically check for memory corruption in low memory, which
1174 is suspected to be caused by BIOS. Even when enabled in the
1175 configuration, it is disabled at runtime. Enable it by
1176 setting "memory_corruption_check=1" on the kernel command
1177 line. By default it scans the low 64k of memory every 60
1178 seconds; see the memory_corruption_check_size and
1179 memory_corruption_check_period parameters in
1180 Documentation/kernel-parameters.txt to adjust this.
1182 When enabled with the default parameters, this option has
1183 almost no overhead, as it reserves a relatively small amount
1184 of memory and scans it infrequently. It both detects corruption
1185 and prevents it from affecting the running system.
1187 It is, however, intended as a diagnostic tool; if repeatable
1188 BIOS-originated corruption always affects the same memory,
1189 you can use memmap= to prevent the kernel from using that
1192 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1193 bool "Set the default setting of memory_corruption_check"
1194 depends on X86_CHECK_BIOS_CORRUPTION
1197 Set whether the default state of memory_corruption_check is
1200 config X86_RESERVE_LOW_64K
1201 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1204 Reserve the first 64K of physical RAM on BIOSes that are known
1205 to potentially corrupt that memory range. A numbers of BIOSes are
1206 known to utilize this area during suspend/resume, so it must not
1207 be used by the kernel.
1209 Set this to N if you are absolutely sure that you trust the BIOS
1210 to get all its memory reservations and usages right.
1212 If you have doubts about the BIOS (e.g. suspend/resume does not
1213 work or there's kernel crashes after certain hardware hotplug
1214 events) and it's not AMI or Phoenix, then you might want to enable
1215 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1216 corruption patterns.
1220 config MATH_EMULATION
1222 prompt "Math emulation" if X86_32
1224 Linux can emulate a math coprocessor (used for floating point
1225 operations) if you don't have one. 486DX and Pentium processors have
1226 a math coprocessor built in, 486SX and 386 do not, unless you added
1227 a 487DX or 387, respectively. (The messages during boot time can
1228 give you some hints here ["man dmesg"].) Everyone needs either a
1229 coprocessor or this emulation.
1231 If you don't have a math coprocessor, you need to say Y here; if you
1232 say Y here even though you have a coprocessor, the coprocessor will
1233 be used nevertheless. (This behavior can be changed with the kernel
1234 command line option "no387", which comes handy if your coprocessor
1235 is broken. Try "man bootparam" or see the documentation of your boot
1236 loader (lilo or loadlin) about how to pass options to the kernel at
1237 boot time.) This means that it is a good idea to say Y here if you
1238 intend to use this kernel on different machines.
1240 More information about the internals of the Linux math coprocessor
1241 emulation can be found in <file:arch/x86/math-emu/README>.
1243 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1244 kernel, it won't hurt.
1247 bool "MTRR (Memory Type Range Register) support"
1249 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1250 the Memory Type Range Registers (MTRRs) may be used to control
1251 processor access to memory ranges. This is most useful if you have
1252 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1253 allows bus write transfers to be combined into a larger transfer
1254 before bursting over the PCI/AGP bus. This can increase performance
1255 of image write operations 2.5 times or more. Saying Y here creates a
1256 /proc/mtrr file which may be used to manipulate your processor's
1257 MTRRs. Typically the X server should use this.
1259 This code has a reasonably generic interface so that similar
1260 control registers on other processors can be easily supported
1263 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1264 Registers (ARRs) which provide a similar functionality to MTRRs. For
1265 these, the ARRs are used to emulate the MTRRs.
1266 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1267 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1268 write-combining. All of these processors are supported by this code
1269 and it makes sense to say Y here if you have one of them.
1271 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1272 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1273 can lead to all sorts of problems, so it's good to say Y here.
1275 You can safely say Y even if your machine doesn't have MTRRs, you'll
1276 just add about 9 KB to your kernel.
1278 See <file:Documentation/x86/mtrr.txt> for more information.
1280 config MTRR_SANITIZER
1282 prompt "MTRR cleanup support"
1285 Convert MTRR layout from continuous to discrete, so X drivers can
1286 add writeback entries.
1288 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1289 The largest mtrr entry size for a continous block can be set with
1294 config MTRR_SANITIZER_ENABLE_DEFAULT
1295 int "MTRR cleanup enable value (0-1)"
1298 depends on MTRR_SANITIZER
1300 Enable mtrr cleanup default value
1302 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1303 int "MTRR cleanup spare reg num (0-7)"
1306 depends on MTRR_SANITIZER
1308 mtrr cleanup spare entries default, it can be changed via
1309 mtrr_spare_reg_nr=N on the kernel command line.
1313 prompt "x86 PAT support"
1316 Use PAT attributes to setup page level cache control.
1318 PATs are the modern equivalents of MTRRs and are much more
1319 flexible than MTRRs.
1321 Say N here if you see bootup problems (boot crash, boot hang,
1322 spontaneous reboots) or a non-working video driver.
1327 bool "EFI runtime service support"
1330 This enables the kernel to use EFI runtime services that are
1331 available (such as the EFI variable services).
1333 This option is only useful on systems that have EFI firmware.
1334 In addition, you should use the latest ELILO loader available
1335 at <http://elilo.sourceforge.net> in order to take advantage
1336 of EFI runtime services. However, even with this option, the
1337 resultant kernel should continue to boot on existing non-EFI
1342 prompt "Enable seccomp to safely compute untrusted bytecode"
1344 This kernel feature is useful for number crunching applications
1345 that may need to compute untrusted bytecode during their
1346 execution. By using pipes or other transports made available to
1347 the process as file descriptors supporting the read/write
1348 syscalls, it's possible to isolate those applications in
1349 their own address space using seccomp. Once seccomp is
1350 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1351 and the task is only allowed to execute a few safe syscalls
1352 defined by each seccomp mode.
1354 If unsure, say Y. Only embedded should say N here.
1356 config CC_STACKPROTECTOR_ALL
1359 config CC_STACKPROTECTOR
1360 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1361 select CC_STACKPROTECTOR_ALL
1363 This option turns on the -fstack-protector GCC feature. This
1364 feature puts, at the beginning of functions, a canary value on
1365 the stack just before the return address, and validates
1366 the value just before actually returning. Stack based buffer
1367 overflows (that need to overwrite this return address) now also
1368 overwrite the canary, which gets detected and the attack is then
1369 neutralized via a kernel panic.
1371 This feature requires gcc version 4.2 or above, or a distribution
1372 gcc with the feature backported. Older versions are automatically
1373 detected and for those versions, this configuration option is
1374 ignored. (and a warning is printed during bootup)
1376 source kernel/Kconfig.hz
1379 bool "kexec system call"
1381 kexec is a system call that implements the ability to shutdown your
1382 current kernel, and to start another kernel. It is like a reboot
1383 but it is independent of the system firmware. And like a reboot
1384 you can start any kernel with it, not just Linux.
1386 The name comes from the similarity to the exec system call.
1388 It is an ongoing process to be certain the hardware in a machine
1389 is properly shutdown, so do not be surprised if this code does not
1390 initially work for you. It may help to enable device hotplugging
1391 support. As of this writing the exact hardware interface is
1392 strongly in flux, so no good recommendation can be made.
1395 bool "kernel crash dumps"
1396 depends on X86_64 || (X86_32 && HIGHMEM)
1398 Generate crash dump after being started by kexec.
1399 This should be normally only set in special crash dump kernels
1400 which are loaded in the main kernel with kexec-tools into
1401 a specially reserved region and then later executed after
1402 a crash by kdump/kexec. The crash dump kernel must be compiled
1403 to a memory address not used by the main kernel or BIOS using
1404 PHYSICAL_START, or it must be built as a relocatable image
1405 (CONFIG_RELOCATABLE=y).
1406 For more details see Documentation/kdump/kdump.txt
1409 bool "kexec jump (EXPERIMENTAL)"
1410 depends on EXPERIMENTAL
1411 depends on KEXEC && HIBERNATION && X86_32
1413 Jump between original kernel and kexeced kernel and invoke
1414 code in physical address mode via KEXEC
1416 config PHYSICAL_START
1417 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1418 default "0x1000000" if X86_NUMAQ
1419 default "0x200000" if X86_64
1422 This gives the physical address where the kernel is loaded.
1424 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1425 bzImage will decompress itself to above physical address and
1426 run from there. Otherwise, bzImage will run from the address where
1427 it has been loaded by the boot loader and will ignore above physical
1430 In normal kdump cases one does not have to set/change this option
1431 as now bzImage can be compiled as a completely relocatable image
1432 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1433 address. This option is mainly useful for the folks who don't want
1434 to use a bzImage for capturing the crash dump and want to use a
1435 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1436 to be specifically compiled to run from a specific memory area
1437 (normally a reserved region) and this option comes handy.
1439 So if you are using bzImage for capturing the crash dump, leave
1440 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1441 Otherwise if you plan to use vmlinux for capturing the crash dump
1442 change this value to start of the reserved region (Typically 16MB
1443 0x1000000). In other words, it can be set based on the "X" value as
1444 specified in the "crashkernel=YM@XM" command line boot parameter
1445 passed to the panic-ed kernel. Typically this parameter is set as
1446 crashkernel=64M@16M. Please take a look at
1447 Documentation/kdump/kdump.txt for more details about crash dumps.
1449 Usage of bzImage for capturing the crash dump is recommended as
1450 one does not have to build two kernels. Same kernel can be used
1451 as production kernel and capture kernel. Above option should have
1452 gone away after relocatable bzImage support is introduced. But it
1453 is present because there are users out there who continue to use
1454 vmlinux for dump capture. This option should go away down the
1457 Don't change this unless you know what you are doing.
1460 bool "Build a relocatable kernel (EXPERIMENTAL)"
1461 depends on EXPERIMENTAL
1463 This builds a kernel image that retains relocation information
1464 so it can be loaded someplace besides the default 1MB.
1465 The relocations tend to make the kernel binary about 10% larger,
1466 but are discarded at runtime.
1468 One use is for the kexec on panic case where the recovery kernel
1469 must live at a different physical address than the primary
1472 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1473 it has been loaded at and the compile time physical address
1474 (CONFIG_PHYSICAL_START) is ignored.
1476 config PHYSICAL_ALIGN
1478 prompt "Alignment value to which kernel should be aligned" if X86_32
1479 default "0x100000" if X86_32
1480 default "0x200000" if X86_64
1481 range 0x2000 0x400000
1483 This value puts the alignment restrictions on physical address
1484 where kernel is loaded and run from. Kernel is compiled for an
1485 address which meets above alignment restriction.
1487 If bootloader loads the kernel at a non-aligned address and
1488 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1489 address aligned to above value and run from there.
1491 If bootloader loads the kernel at a non-aligned address and
1492 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1493 load address and decompress itself to the address it has been
1494 compiled for and run from there. The address for which kernel is
1495 compiled already meets above alignment restrictions. Hence the
1496 end result is that kernel runs from a physical address meeting
1497 above alignment restrictions.
1499 Don't change this unless you know what you are doing.
1502 bool "Support for hot-pluggable CPUs"
1503 depends on SMP && HOTPLUG
1505 Say Y here to allow turning CPUs off and on. CPUs can be
1506 controlled through /sys/devices/system/cpu.
1507 ( Note: power management support will enable this option
1508 automatically on SMP systems. )
1509 Say N if you want to disable CPU hotplug.
1513 prompt "Compat VDSO support"
1514 depends on X86_32 || IA32_EMULATION
1516 Map the 32-bit VDSO to the predictable old-style address too.
1518 Say N here if you are running a sufficiently recent glibc
1519 version (2.3.3 or later), to remove the high-mapped
1520 VDSO mapping and to exclusively use the randomized VDSO.
1525 bool "Built-in kernel command line"
1528 Allow for specifying boot arguments to the kernel at
1529 build time. On some systems (e.g. embedded ones), it is
1530 necessary or convenient to provide some or all of the
1531 kernel boot arguments with the kernel itself (that is,
1532 to not rely on the boot loader to provide them.)
1534 To compile command line arguments into the kernel,
1535 set this option to 'Y', then fill in the
1536 the boot arguments in CONFIG_CMDLINE.
1538 Systems with fully functional boot loaders (i.e. non-embedded)
1539 should leave this option set to 'N'.
1542 string "Built-in kernel command string"
1543 depends on CMDLINE_BOOL
1546 Enter arguments here that should be compiled into the kernel
1547 image and used at boot time. If the boot loader provides a
1548 command line at boot time, it is appended to this string to
1549 form the full kernel command line, when the system boots.
1551 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1552 change this behavior.
1554 In most cases, the command line (whether built-in or provided
1555 by the boot loader) should specify the device for the root
1558 config CMDLINE_OVERRIDE
1559 bool "Built-in command line overrides boot loader arguments"
1561 depends on CMDLINE_BOOL
1563 Set this option to 'Y' to have the kernel ignore the boot loader
1564 command line, and use ONLY the built-in command line.
1566 This is used to work around broken boot loaders. This should
1567 be set to 'N' under normal conditions.
1571 config ARCH_ENABLE_MEMORY_HOTPLUG
1573 depends on X86_64 || (X86_32 && HIGHMEM)
1575 config ARCH_ENABLE_MEMORY_HOTREMOVE
1577 depends on MEMORY_HOTPLUG
1579 config HAVE_ARCH_EARLY_PFN_TO_NID
1583 menu "Power management and ACPI options"
1585 config ARCH_HIBERNATION_HEADER
1587 depends on X86_64 && HIBERNATION
1589 source "kernel/power/Kconfig"
1591 source "drivers/acpi/Kconfig"
1596 depends on APM || APM_MODULE
1599 tristate "APM (Advanced Power Management) BIOS support"
1600 depends on X86_32 && PM_SLEEP
1602 APM is a BIOS specification for saving power using several different
1603 techniques. This is mostly useful for battery powered laptops with
1604 APM compliant BIOSes. If you say Y here, the system time will be
1605 reset after a RESUME operation, the /proc/apm device will provide
1606 battery status information, and user-space programs will receive
1607 notification of APM "events" (e.g. battery status change).
1609 If you select "Y" here, you can disable actual use of the APM
1610 BIOS by passing the "apm=off" option to the kernel at boot time.
1612 Note that the APM support is almost completely disabled for
1613 machines with more than one CPU.
1615 In order to use APM, you will need supporting software. For location
1616 and more information, read <file:Documentation/power/pm.txt> and the
1617 Battery Powered Linux mini-HOWTO, available from
1618 <http://www.tldp.org/docs.html#howto>.
1620 This driver does not spin down disk drives (see the hdparm(8)
1621 manpage ("man 8 hdparm") for that), and it doesn't turn off
1622 VESA-compliant "green" monitors.
1624 This driver does not support the TI 4000M TravelMate and the ACER
1625 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1626 desktop machines also don't have compliant BIOSes, and this driver
1627 may cause those machines to panic during the boot phase.
1629 Generally, if you don't have a battery in your machine, there isn't
1630 much point in using this driver and you should say N. If you get
1631 random kernel OOPSes or reboots that don't seem to be related to
1632 anything, try disabling/enabling this option (or disabling/enabling
1635 Some other things you should try when experiencing seemingly random,
1638 1) make sure that you have enough swap space and that it is
1640 2) pass the "no-hlt" option to the kernel
1641 3) switch on floating point emulation in the kernel and pass
1642 the "no387" option to the kernel
1643 4) pass the "floppy=nodma" option to the kernel
1644 5) pass the "mem=4M" option to the kernel (thereby disabling
1645 all but the first 4 MB of RAM)
1646 6) make sure that the CPU is not over clocked.
1647 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1648 8) disable the cache from your BIOS settings
1649 9) install a fan for the video card or exchange video RAM
1650 10) install a better fan for the CPU
1651 11) exchange RAM chips
1652 12) exchange the motherboard.
1654 To compile this driver as a module, choose M here: the
1655 module will be called apm.
1659 config APM_IGNORE_USER_SUSPEND
1660 bool "Ignore USER SUSPEND"
1662 This option will ignore USER SUSPEND requests. On machines with a
1663 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1664 series notebooks, it is necessary to say Y because of a BIOS bug.
1666 config APM_DO_ENABLE
1667 bool "Enable PM at boot time"
1669 Enable APM features at boot time. From page 36 of the APM BIOS
1670 specification: "When disabled, the APM BIOS does not automatically
1671 power manage devices, enter the Standby State, enter the Suspend
1672 State, or take power saving steps in response to CPU Idle calls."
1673 This driver will make CPU Idle calls when Linux is idle (unless this
1674 feature is turned off -- see "Do CPU IDLE calls", below). This
1675 should always save battery power, but more complicated APM features
1676 will be dependent on your BIOS implementation. You may need to turn
1677 this option off if your computer hangs at boot time when using APM
1678 support, or if it beeps continuously instead of suspending. Turn
1679 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1680 T400CDT. This is off by default since most machines do fine without
1684 bool "Make CPU Idle calls when idle"
1686 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1687 On some machines, this can activate improved power savings, such as
1688 a slowed CPU clock rate, when the machine is idle. These idle calls
1689 are made after the idle loop has run for some length of time (e.g.,
1690 333 mS). On some machines, this will cause a hang at boot time or
1691 whenever the CPU becomes idle. (On machines with more than one CPU,
1692 this option does nothing.)
1694 config APM_DISPLAY_BLANK
1695 bool "Enable console blanking using APM"
1697 Enable console blanking using the APM. Some laptops can use this to
1698 turn off the LCD backlight when the screen blanker of the Linux
1699 virtual console blanks the screen. Note that this is only used by
1700 the virtual console screen blanker, and won't turn off the backlight
1701 when using the X Window system. This also doesn't have anything to
1702 do with your VESA-compliant power-saving monitor. Further, this
1703 option doesn't work for all laptops -- it might not turn off your
1704 backlight at all, or it might print a lot of errors to the console,
1705 especially if you are using gpm.
1707 config APM_ALLOW_INTS
1708 bool "Allow interrupts during APM BIOS calls"
1710 Normally we disable external interrupts while we are making calls to
1711 the APM BIOS as a measure to lessen the effects of a badly behaving
1712 BIOS implementation. The BIOS should reenable interrupts if it
1713 needs to. Unfortunately, some BIOSes do not -- especially those in
1714 many of the newer IBM Thinkpads. If you experience hangs when you
1715 suspend, try setting this to Y. Otherwise, say N.
1719 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1721 source "drivers/cpuidle/Kconfig"
1723 source "drivers/idle/Kconfig"
1728 menu "Bus options (PCI etc.)"
1733 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1735 Find out whether you have a PCI motherboard. PCI is the name of a
1736 bus system, i.e. the way the CPU talks to the other stuff inside
1737 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1738 VESA. If you have PCI, say Y, otherwise N.
1741 prompt "PCI access mode"
1742 depends on X86_32 && PCI
1745 On PCI systems, the BIOS can be used to detect the PCI devices and
1746 determine their configuration. However, some old PCI motherboards
1747 have BIOS bugs and may crash if this is done. Also, some embedded
1748 PCI-based systems don't have any BIOS at all. Linux can also try to
1749 detect the PCI hardware directly without using the BIOS.
1751 With this option, you can specify how Linux should detect the
1752 PCI devices. If you choose "BIOS", the BIOS will be used,
1753 if you choose "Direct", the BIOS won't be used, and if you
1754 choose "MMConfig", then PCI Express MMCONFIG will be used.
1755 If you choose "Any", the kernel will try MMCONFIG, then the
1756 direct access method and falls back to the BIOS if that doesn't
1757 work. If unsure, go with the default, which is "Any".
1762 config PCI_GOMMCONFIG
1779 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1781 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1784 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1788 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1792 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1799 bool "Support mmconfig PCI config space access"
1800 depends on X86_64 && PCI && ACPI
1803 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1804 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1806 DMA remapping (DMAR) devices support enables independent address
1807 translations for Direct Memory Access (DMA) from devices.
1808 These DMA remapping devices are reported via ACPI tables
1809 and include PCI device scope covered by these DMA
1812 config DMAR_DEFAULT_ON
1814 prompt "Enable DMA Remapping Devices by default"
1817 Selecting this option will enable a DMAR device at boot time if
1818 one is found. If this option is not selected, DMAR support can
1819 be enabled by passing intel_iommu=on to the kernel. It is
1820 recommended you say N here while the DMAR code remains
1825 prompt "Support for Graphics workaround"
1828 Current Graphics drivers tend to use physical address
1829 for DMA and avoid using DMA APIs. Setting this config
1830 option permits the IOMMU driver to set a unity map for
1831 all the OS-visible memory. Hence the driver can continue
1832 to use physical addresses for DMA.
1834 config DMAR_FLOPPY_WA
1838 Floppy disk drivers are know to bypass DMA API calls
1839 thereby failing to work when IOMMU is enabled. This
1840 workaround will setup a 1:1 mapping for the first
1841 16M to make floppy (an ISA device) work.
1844 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1845 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1848 Supports Interrupt remapping for IO-APIC and MSI devices.
1849 To use x2apic mode in the CPU's which support x2APIC enhancements or
1850 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1852 source "drivers/pci/pcie/Kconfig"
1854 source "drivers/pci/Kconfig"
1856 # x86_64 have no ISA slots, but do have ISA-style DMA.
1865 Find out whether you have ISA slots on your motherboard. ISA is the
1866 name of a bus system, i.e. the way the CPU talks to the other stuff
1867 inside your box. Other bus systems are PCI, EISA, MicroChannel
1868 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1869 newer boards don't support it. If you have ISA, say Y, otherwise N.
1875 The Extended Industry Standard Architecture (EISA) bus was
1876 developed as an open alternative to the IBM MicroChannel bus.
1878 The EISA bus provided some of the features of the IBM MicroChannel
1879 bus while maintaining backward compatibility with cards made for
1880 the older ISA bus. The EISA bus saw limited use between 1988 and
1881 1995 when it was made obsolete by the PCI bus.
1883 Say Y here if you are building a kernel for an EISA-based machine.
1887 source "drivers/eisa/Kconfig"
1892 MicroChannel Architecture is found in some IBM PS/2 machines and
1893 laptops. It is a bus system similar to PCI or ISA. See
1894 <file:Documentation/mca.txt> (and especially the web page given
1895 there) before attempting to build an MCA bus kernel.
1897 source "drivers/mca/Kconfig"
1900 tristate "NatSemi SCx200 support"
1902 This provides basic support for National Semiconductor's
1903 (now AMD's) Geode processors. The driver probes for the
1904 PCI-IDs of several on-chip devices, so its a good dependency
1905 for other scx200_* drivers.
1907 If compiled as a module, the driver is named scx200.
1909 config SCx200HR_TIMER
1910 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1911 depends on SCx200 && GENERIC_TIME
1914 This driver provides a clocksource built upon the on-chip
1915 27MHz high-resolution timer. Its also a workaround for
1916 NSC Geode SC-1100's buggy TSC, which loses time when the
1917 processor goes idle (as is done by the scheduler). The
1918 other workaround is idle=poll boot option.
1920 config GEODE_MFGPT_TIMER
1922 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1923 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1925 This driver provides a clock event source based on the MFGPT
1926 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1927 MFGPTs have a better resolution and max interval than the
1928 generic PIT, and are suitable for use as high-res timers.
1931 bool "One Laptop Per Child support"
1934 Add support for detecting the unique features of the OLPC
1941 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1943 source "drivers/pcmcia/Kconfig"
1945 source "drivers/pci/hotplug/Kconfig"
1950 menu "Executable file formats / Emulations"
1952 source "fs/Kconfig.binfmt"
1954 config IA32_EMULATION
1955 bool "IA32 Emulation"
1957 select COMPAT_BINFMT_ELF
1959 Include code to run 32-bit programs under a 64-bit kernel. You should
1960 likely turn this on, unless you're 100% sure that you don't have any
1961 32-bit programs left.
1964 tristate "IA32 a.out support"
1965 depends on IA32_EMULATION
1967 Support old a.out binaries in the 32bit emulation.
1971 depends on IA32_EMULATION
1973 config COMPAT_FOR_U64_ALIGNMENT
1977 config SYSVIPC_COMPAT
1979 depends on COMPAT && SYSVIPC
1984 config HAVE_ATOMIC_IOMAP
1988 source "net/Kconfig"
1990 source "drivers/Kconfig"
1992 source "drivers/firmware/Kconfig"
1996 source "arch/x86/Kconfig.debug"
1998 source "security/Kconfig"
2000 source "crypto/Kconfig"
2002 source "arch/x86/kvm/Kconfig"
2004 source "lib/Kconfig"
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