2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
38 select HAVE_ARCH_KGDB if !X86_VOYAGER
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
136 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
143 depends on !SMP || !X86_VOYAGER
145 config ARCH_SUSPEND_POSSIBLE
147 depends on !X86_VOYAGER
153 config ARCH_POPULATES_NODE_MAP
160 config ARCH_SUPPORTS_OPTIMIZED_INLINING
163 # Use the generic interrupt handling code in kernel/irq/:
164 config GENERIC_HARDIRQS
168 config GENERIC_IRQ_PROBE
172 config GENERIC_PENDING_IRQ
174 depends on GENERIC_HARDIRQS && SMP
179 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
182 config USE_GENERIC_SMP_HELPERS
188 depends on X86_32 && SMP
192 depends on X86_64 && SMP
197 depends on (X86_32 && !X86_VOYAGER) || X86_64
200 config X86_BIOS_REBOOT
202 depends on !X86_VOYAGER
205 config X86_TRAMPOLINE
207 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
212 source "init/Kconfig"
213 source "kernel/Kconfig.freezer"
215 menu "Processor type and features"
217 source "kernel/time/Kconfig"
220 bool "Symmetric multi-processing support"
222 This enables support for systems with more than one CPU. If you have
223 a system with only one CPU, like most personal computers, say N. If
224 you have a system with more than one CPU, say Y.
226 If you say N here, the kernel will run on single and multiprocessor
227 machines, but will use only one CPU of a multiprocessor machine. If
228 you say Y here, the kernel will run on many, but not all,
229 singleprocessor machines. On a singleprocessor machine, the kernel
230 will run faster if you say N here.
232 Note that if you say Y here and choose architecture "586" or
233 "Pentium" under "Processor family", the kernel will not work on 486
234 architectures. Similarly, multiprocessor kernels for the "PPro"
235 architecture may not work on all Pentium based boards.
237 People using multiprocessor machines who say Y here should also say
238 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
239 Management" code will be disabled if you say Y here.
241 See also <file:Documentation/i386/IO-APIC.txt>,
242 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
243 <http://www.tldp.org/docs.html#howto>.
245 If you don't know what to do here, say N.
247 config X86_HAS_BOOT_CPU_ID
249 depends on X86_VOYAGER
252 bool "Support sparse irq numbering"
253 depends on PCI_MSI || HT_IRQ
255 This enables support for sparse irqs. This is useful for distro
256 kernels that want to define a high CONFIG_NR_CPUS value but still
257 want to have low kernel memory footprint on smaller machines.
259 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
260 out the irq_desc[] array in a more NUMA-friendly way. )
262 If you don't know what to do here, say N.
264 config NUMA_MIGRATE_IRQ_DESC
265 bool "Move irq desc when changing irq smp_affinity"
266 depends on SPARSE_IRQ && NUMA
269 This enables moving irq_desc to cpu/node that irq will use handled.
271 If you don't know what to do here, say N.
273 config X86_FIND_SMP_CONFIG
275 depends on X86_MPPARSE || X86_VOYAGER
278 bool "Enable MPS table" if ACPI
280 depends on X86_LOCAL_APIC
282 For old smp systems that do not have proper acpi support. Newer systems
283 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
286 prompt "Subarchitecture Type"
292 Choose this option if your computer is a standard PC or compatible.
298 Select this for an AMD Elan processor.
300 Do not use this option for K6/Athlon/Opteron processors!
302 If unsure, choose "PC-compatible" instead.
306 depends on X86_32 && (SMP || BROKEN) && !PCI
308 Voyager is an MCA-based 32-way capable SMP architecture proprietary
309 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
313 If you do not specifically know you have a Voyager based machine,
314 say N here, otherwise the kernel you build will not be bootable.
316 config X86_GENERICARCH
317 bool "Generic architecture"
320 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
321 subarchitectures. It is intended for a generic binary kernel.
322 if you select them all, kernel will probe it one by one. and will
328 bool "NUMAQ (IBM/Sequent)"
329 depends on SMP && X86_32 && PCI && X86_MPPARSE
332 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
333 NUMA multiquad box. This changes the way that processors are
334 bootstrapped, and uses Clustered Logical APIC addressing mode instead
335 of Flat Logical. You will need a new lynxer.elf file to flash your
336 firmware with - send email to <Martin.Bligh@us.ibm.com>.
339 bool "Summit/EXA (IBM x440)"
340 depends on X86_32 && SMP
342 This option is needed for IBM systems that use the Summit/EXA chipset.
343 In particular, it is needed for the x440.
346 bool "Support for Unisys ES7000 IA32 series"
347 depends on X86_32 && SMP
349 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
350 supposed to run on an IA32-based Unisys ES7000 system.
353 bool "Support for big SMP systems with more than 8 CPUs"
354 depends on X86_32 && SMP
356 This option is needed for the systems that have more than 8 CPUs
357 and if the system is not of any sub-arch type above.
362 bool "Support for ScaleMP vSMP"
364 depends on X86_64 && PCI
366 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
367 supposed to run on these EM64T-based machines. Only choose this option
368 if you have one of these machines.
373 bool "SGI 320/540 (Visual Workstation)"
374 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
376 The SGI Visual Workstation series is an IA32-based workstation
377 based on SGI systems chips with some legacy PC hardware attached.
379 Say Y here to create a kernel to run on the SGI 320 or 540.
381 A kernel compiled for the Visual Workstation will run on general
382 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
385 bool "RDC R-321x SoC"
388 select X86_REBOOTFIXUPS
390 This option is needed for RDC R-321x system-on-chip, also known
392 If you don't have one of these chips, you should say N here.
394 config SCHED_OMIT_FRAME_POINTER
396 prompt "Single-depth WCHAN output"
399 Calculate simpler /proc/<PID>/wchan values. If this option
400 is disabled then wchan values will recurse back to the
401 caller function. This provides more accurate wchan values,
402 at the expense of slightly more scheduling overhead.
404 If in doubt, say "Y".
406 menuconfig PARAVIRT_GUEST
407 bool "Paravirtualized guest support"
409 Say Y here to get to see options related to running Linux under
410 various hypervisors. This option alone does not add any kernel code.
412 If you say N, all options in this submenu will be skipped and disabled.
416 source "arch/x86/xen/Kconfig"
419 bool "VMI Guest support"
422 depends on !X86_VOYAGER
424 VMI provides a paravirtualized interface to the VMware ESX server
425 (it could be used by other hypervisors in theory too, but is not
426 at the moment), by linking the kernel to a GPL-ed ROM module
427 provided by the hypervisor.
430 bool "KVM paravirtualized clock"
432 select PARAVIRT_CLOCK
433 depends on !X86_VOYAGER
435 Turning on this option will allow you to run a paravirtualized clock
436 when running over the KVM hypervisor. Instead of relying on a PIT
437 (or probably other) emulation by the underlying device model, the host
438 provides the guest with timing infrastructure such as time of day, and
442 bool "KVM Guest support"
444 depends on !X86_VOYAGER
446 This option enables various optimizations for running under the KVM
449 source "arch/x86/lguest/Kconfig"
452 bool "Enable paravirtualization code"
453 depends on !X86_VOYAGER
455 This changes the kernel so it can modify itself when it is run
456 under a hypervisor, potentially improving performance significantly
457 over full virtualization. However, when run without a hypervisor
458 the kernel is theoretically slower and slightly larger.
460 config PARAVIRT_CLOCK
466 config PARAVIRT_DEBUG
467 bool "paravirt-ops debugging"
468 depends on PARAVIRT && DEBUG_KERNEL
470 Enable to debug paravirt_ops internals. Specifically, BUG if
471 a paravirt_op is missing when it is called.
476 This option adds a kernel parameter 'memtest', which allows memtest
478 memtest=0, mean disabled; -- default
479 memtest=1, mean do 1 test pattern;
481 memtest=4, mean do 4 test patterns.
482 If you are unsure how to answer this question, answer N.
484 config X86_SUMMIT_NUMA
486 depends on X86_32 && NUMA && X86_GENERICARCH
488 config X86_CYCLONE_TIMER
490 depends on X86_GENERICARCH
492 source "arch/x86/Kconfig.cpu"
496 prompt "HPET Timer Support" if X86_32
498 Use the IA-PC HPET (High Precision Event Timer) to manage
499 time in preference to the PIT and RTC, if a HPET is
501 HPET is the next generation timer replacing legacy 8254s.
502 The HPET provides a stable time base on SMP
503 systems, unlike the TSC, but it is more expensive to access,
504 as it is off-chip. You can find the HPET spec at
505 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
507 You can safely choose Y here. However, HPET will only be
508 activated if the platform and the BIOS support this feature.
509 Otherwise the 8254 will be used for timing services.
511 Choose N to continue using the legacy 8254 timer.
513 config HPET_EMULATE_RTC
515 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
517 # Mark as embedded because too many people got it wrong.
518 # The code disables itself when not needed.
521 bool "Enable DMI scanning" if EMBEDDED
523 Enabled scanning of DMI to identify machine quirks. Say Y
524 here unless you have verified that your setup is not
525 affected by entries in the DMI blacklist. Required by PNP
529 bool "GART IOMMU support" if EMBEDDED
533 depends on X86_64 && PCI
535 Support for full DMA access of devices with 32bit memory access only
536 on systems with more than 3GB. This is usually needed for USB,
537 sound, many IDE/SATA chipsets and some other devices.
538 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
539 based hardware IOMMU and a software bounce buffer based IOMMU used
540 on Intel systems and as fallback.
541 The code is only active when needed (enough memory and limited
542 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
546 bool "IBM Calgary IOMMU support"
548 depends on X86_64 && PCI && EXPERIMENTAL
550 Support for hardware IOMMUs in IBM's xSeries x366 and x460
551 systems. Needed to run systems with more than 3GB of memory
552 properly with 32-bit PCI devices that do not support DAC
553 (Double Address Cycle). Calgary also supports bus level
554 isolation, where all DMAs pass through the IOMMU. This
555 prevents them from going anywhere except their intended
556 destination. This catches hard-to-find kernel bugs and
557 mis-behaving drivers and devices that do not use the DMA-API
558 properly to set up their DMA buffers. The IOMMU can be
559 turned off at boot time with the iommu=off parameter.
560 Normally the kernel will make the right choice by itself.
563 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
565 prompt "Should Calgary be enabled by default?"
566 depends on CALGARY_IOMMU
568 Should Calgary be enabled by default? if you choose 'y', Calgary
569 will be used (if it exists). If you choose 'n', Calgary will not be
570 used even if it exists. If you choose 'n' and would like to use
571 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
575 bool "AMD IOMMU support"
578 depends on X86_64 && PCI && ACPI
580 With this option you can enable support for AMD IOMMU hardware in
581 your system. An IOMMU is a hardware component which provides
582 remapping of DMA memory accesses from devices. With an AMD IOMMU you
583 can isolate the the DMA memory of different devices and protect the
584 system from misbehaving device drivers or hardware.
586 You can find out if your system has an AMD IOMMU if you look into
587 your BIOS for an option to enable it or if you have an IVRS ACPI
590 config AMD_IOMMU_STATS
591 bool "Export AMD IOMMU statistics to debugfs"
595 This option enables code in the AMD IOMMU driver to collect various
596 statistics about whats happening in the driver and exports that
597 information to userspace via debugfs.
600 # need this always selected by IOMMU for the VIA workaround
604 Support for software bounce buffers used on x86-64 systems
605 which don't have a hardware IOMMU (e.g. the current generation
606 of Intel's x86-64 CPUs). Using this PCI devices which can only
607 access 32-bits of memory can be used on systems with more than
608 3 GB of memory. If unsure, say Y.
611 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
614 def_bool (AMD_IOMMU || DMAR)
617 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
618 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
619 select CPUMASK_OFFSTACK
622 Configure maximum number of CPUS and NUMA Nodes for this architecture.
626 int "Maximum number of CPUs" if SMP && !MAXSMP
627 range 2 512 if SMP && !MAXSMP
629 default "4096" if MAXSMP
630 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
633 This allows you to specify the maximum number of CPUs which this
634 kernel will support. The maximum supported value is 512 and the
635 minimum value which makes sense is 2.
637 This is purely to save memory - each supported CPU adds
638 approximately eight kilobytes to the kernel image.
641 bool "SMT (Hyperthreading) scheduler support"
644 SMT scheduler support improves the CPU scheduler's decision making
645 when dealing with Intel Pentium 4 chips with HyperThreading at a
646 cost of slightly increased overhead in some places. If unsure say
651 prompt "Multi-core scheduler support"
654 Multi-core scheduler support improves the CPU scheduler's decision
655 making when dealing with multi-core CPU chips at a cost of slightly
656 increased overhead in some places. If unsure say N here.
658 source "kernel/Kconfig.preempt"
661 bool "Local APIC support on uniprocessors"
662 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
664 A local APIC (Advanced Programmable Interrupt Controller) is an
665 integrated interrupt controller in the CPU. If you have a single-CPU
666 system which has a processor with a local APIC, you can say Y here to
667 enable and use it. If you say Y here even though your machine doesn't
668 have a local APIC, then the kernel will still run with no slowdown at
669 all. The local APIC supports CPU-generated self-interrupts (timer,
670 performance counters), and the NMI watchdog which detects hard
674 bool "IO-APIC support on uniprocessors"
675 depends on X86_UP_APIC
677 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
678 SMP-capable replacement for PC-style interrupt controllers. Most
679 SMP systems and many recent uniprocessor systems have one.
681 If you have a single-CPU system with an IO-APIC, you can say Y here
682 to use it. If you say Y here even though your machine doesn't have
683 an IO-APIC, then the kernel will still run with no slowdown at all.
685 config X86_LOCAL_APIC
687 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
691 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
693 config X86_VISWS_APIC
695 depends on X86_32 && X86_VISWS
697 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
698 bool "Reroute for broken boot IRQs"
700 depends on X86_IO_APIC
702 This option enables a workaround that fixes a source of
703 spurious interrupts. This is recommended when threaded
704 interrupt handling is used on systems where the generation of
705 superfluous "boot interrupts" cannot be disabled.
707 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
708 entry in the chipset's IO-APIC is masked (as, e.g. the RT
709 kernel does during interrupt handling). On chipsets where this
710 boot IRQ generation cannot be disabled, this workaround keeps
711 the original IRQ line masked so that only the equivalent "boot
712 IRQ" is delivered to the CPUs. The workaround also tells the
713 kernel to set up the IRQ handler on the boot IRQ line. In this
714 way only one interrupt is delivered to the kernel. Otherwise
715 the spurious second interrupt may cause the kernel to bring
716 down (vital) interrupt lines.
718 Only affects "broken" chipsets. Interrupt sharing may be
719 increased on these systems.
722 bool "Machine Check Exception"
723 depends on !X86_VOYAGER
725 Machine Check Exception support allows the processor to notify the
726 kernel if it detects a problem (e.g. overheating, component failure).
727 The action the kernel takes depends on the severity of the problem,
728 ranging from a warning message on the console, to halting the machine.
729 Your processor must be a Pentium or newer to support this - check the
730 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
731 have a design flaw which leads to false MCE events - hence MCE is
732 disabled on all P5 processors, unless explicitly enabled with "mce"
733 as a boot argument. Similarly, if MCE is built in and creates a
734 problem on some new non-standard machine, you can boot with "nomce"
735 to disable it. MCE support simply ignores non-MCE processors like
736 the 386 and 486, so nearly everyone can say Y here.
740 prompt "Intel MCE features"
741 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
743 Additional support for intel specific MCE features such as
748 prompt "AMD MCE features"
749 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
751 Additional support for AMD specific MCE features such as
752 the DRAM Error Threshold.
754 config X86_MCE_NONFATAL
755 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
756 depends on X86_32 && X86_MCE
758 Enabling this feature starts a timer that triggers every 5 seconds which
759 will look at the machine check registers to see if anything happened.
760 Non-fatal problems automatically get corrected (but still logged).
761 Disable this if you don't want to see these messages.
762 Seeing the messages this option prints out may be indicative of dying
763 or out-of-spec (ie, overclocked) hardware.
764 This option only does something on certain CPUs.
765 (AMD Athlon/Duron and Intel Pentium 4)
767 config X86_MCE_P4THERMAL
768 bool "check for P4 thermal throttling interrupt."
769 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
771 Enabling this feature will cause a message to be printed when the P4
772 enters thermal throttling.
775 bool "Enable VM86 support" if EMBEDDED
779 This option is required by programs like DOSEMU to run 16-bit legacy
780 code on X86 processors. It also may be needed by software like
781 XFree86 to initialize some video cards via BIOS. Disabling this
782 option saves about 6k.
785 tristate "Toshiba Laptop support"
788 This adds a driver to safely access the System Management Mode of
789 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
790 not work on models with a Phoenix BIOS. The System Management Mode
791 is used to set the BIOS and power saving options on Toshiba portables.
793 For information on utilities to make use of this driver see the
794 Toshiba Linux utilities web site at:
795 <http://www.buzzard.org.uk/toshiba/>.
797 Say Y if you intend to run this kernel on a Toshiba portable.
801 tristate "Dell laptop support"
803 This adds a driver to safely access the System Management Mode
804 of the CPU on the Dell Inspiron 8000. The System Management Mode
805 is used to read cpu temperature and cooling fan status and to
806 control the fans on the I8K portables.
808 This driver has been tested only on the Inspiron 8000 but it may
809 also work with other Dell laptops. You can force loading on other
810 models by passing the parameter `force=1' to the module. Use at
813 For information on utilities to make use of this driver see the
814 I8K Linux utilities web site at:
815 <http://people.debian.org/~dz/i8k/>
817 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
820 config X86_REBOOTFIXUPS
821 bool "Enable X86 board specific fixups for reboot"
824 This enables chipset and/or board specific fixups to be done
825 in order to get reboot to work correctly. This is only needed on
826 some combinations of hardware and BIOS. The symptom, for which
827 this config is intended, is when reboot ends with a stalled/hung
830 Currently, the only fixup is for the Geode machines using
831 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
833 Say Y if you want to enable the fixup. Currently, it's safe to
834 enable this option even if you don't need it.
838 tristate "/dev/cpu/microcode - microcode support"
841 If you say Y here, you will be able to update the microcode on
842 certain Intel and AMD processors. The Intel support is for the
843 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
844 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
845 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
846 You will obviously need the actual microcode binary data itself
847 which is not shipped with the Linux kernel.
849 This option selects the general module only, you need to select
850 at least one vendor specific module as well.
852 To compile this driver as a module, choose M here: the
853 module will be called microcode.
855 config MICROCODE_INTEL
856 bool "Intel microcode patch loading support"
861 This options enables microcode patch loading support for Intel
864 For latest news and information on obtaining all the required
865 Intel ingredients for this driver, check:
866 <http://www.urbanmyth.org/microcode/>.
869 bool "AMD microcode patch loading support"
873 If you select this option, microcode patch loading support for AMD
874 processors will be enabled.
876 config MICROCODE_OLD_INTERFACE
881 tristate "/dev/cpu/*/msr - Model-specific register support"
883 This device gives privileged processes access to the x86
884 Model-Specific Registers (MSRs). It is a character device with
885 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
886 MSR accesses are directed to a specific CPU on multi-processor
890 tristate "/dev/cpu/*/cpuid - CPU information support"
892 This device gives processes access to the x86 CPUID instruction to
893 be executed on a specific processor. It is a character device
894 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
898 prompt "High Memory Support"
899 default HIGHMEM4G if !X86_NUMAQ
900 default HIGHMEM64G if X86_NUMAQ
905 depends on !X86_NUMAQ
907 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
908 However, the address space of 32-bit x86 processors is only 4
909 Gigabytes large. That means that, if you have a large amount of
910 physical memory, not all of it can be "permanently mapped" by the
911 kernel. The physical memory that's not permanently mapped is called
914 If you are compiling a kernel which will never run on a machine with
915 more than 1 Gigabyte total physical RAM, answer "off" here (default
916 choice and suitable for most users). This will result in a "3GB/1GB"
917 split: 3GB are mapped so that each process sees a 3GB virtual memory
918 space and the remaining part of the 4GB virtual memory space is used
919 by the kernel to permanently map as much physical memory as
922 If the machine has between 1 and 4 Gigabytes physical RAM, then
925 If more than 4 Gigabytes is used then answer "64GB" here. This
926 selection turns Intel PAE (Physical Address Extension) mode on.
927 PAE implements 3-level paging on IA32 processors. PAE is fully
928 supported by Linux, PAE mode is implemented on all recent Intel
929 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
930 then the kernel will not boot on CPUs that don't support PAE!
932 The actual amount of total physical memory will either be
933 auto detected or can be forced by using a kernel command line option
934 such as "mem=256M". (Try "man bootparam" or see the documentation of
935 your boot loader (lilo or loadlin) about how to pass options to the
936 kernel at boot time.)
938 If unsure, say "off".
942 depends on !X86_NUMAQ
944 Select this if you have a 32-bit processor and between 1 and 4
945 gigabytes of physical RAM.
949 depends on !M386 && !M486
952 Select this if you have a 32-bit processor and more than 4
953 gigabytes of physical RAM.
958 depends on EXPERIMENTAL
959 prompt "Memory split" if EMBEDDED
963 Select the desired split between kernel and user memory.
965 If the address range available to the kernel is less than the
966 physical memory installed, the remaining memory will be available
967 as "high memory". Accessing high memory is a little more costly
968 than low memory, as it needs to be mapped into the kernel first.
969 Note that increasing the kernel address space limits the range
970 available to user programs, making the address space there
971 tighter. Selecting anything other than the default 3G/1G split
972 will also likely make your kernel incompatible with binary-only
975 If you are not absolutely sure what you are doing, leave this
979 bool "3G/1G user/kernel split"
980 config VMSPLIT_3G_OPT
982 bool "3G/1G user/kernel split (for full 1G low memory)"
984 bool "2G/2G user/kernel split"
985 config VMSPLIT_2G_OPT
987 bool "2G/2G user/kernel split (for full 2G low memory)"
989 bool "1G/3G user/kernel split"
994 default 0xB0000000 if VMSPLIT_3G_OPT
995 default 0x80000000 if VMSPLIT_2G
996 default 0x78000000 if VMSPLIT_2G_OPT
997 default 0x40000000 if VMSPLIT_1G
1003 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1006 bool "PAE (Physical Address Extension) Support"
1007 depends on X86_32 && !HIGHMEM4G
1009 PAE is required for NX support, and furthermore enables
1010 larger swapspace support for non-overcommit purposes. It
1011 has the cost of more pagetable lookup overhead, and also
1012 consumes more pagetable space per process.
1014 config ARCH_PHYS_ADDR_T_64BIT
1015 def_bool X86_64 || X86_PAE
1017 config DIRECT_GBPAGES
1018 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1022 Allow the kernel linear mapping to use 1GB pages on CPUs that
1023 support it. This can improve the kernel's performance a tiny bit by
1024 reducing TLB pressure. If in doubt, say "Y".
1026 # Common NUMA Features
1028 bool "Numa Memory Allocation and Scheduler Support"
1030 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1032 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1034 Enable NUMA (Non Uniform Memory Access) support.
1036 The kernel will try to allocate memory used by a CPU on the
1037 local memory controller of the CPU and add some more
1038 NUMA awareness to the kernel.
1040 For 64-bit this is recommended if the system is Intel Core i7
1041 (or later), AMD Opteron, or EM64T NUMA.
1043 For 32-bit this is only needed on (rare) 32-bit-only platforms
1044 that support NUMA topologies, such as NUMAQ / Summit, or if you
1045 boot a 32-bit kernel on a 64-bit NUMA platform.
1047 Otherwise, you should say N.
1049 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1050 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1054 prompt "Old style AMD Opteron NUMA detection"
1055 depends on X86_64 && NUMA && PCI
1057 Enable K8 NUMA node topology detection. You should say Y here if
1058 you have a multi processor AMD K8 system. This uses an old
1059 method to read the NUMA configuration directly from the builtin
1060 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1061 instead, which also takes priority if both are compiled in.
1063 config X86_64_ACPI_NUMA
1065 prompt "ACPI NUMA detection"
1066 depends on X86_64 && NUMA && ACPI && PCI
1069 Enable ACPI SRAT based node topology detection.
1071 # Some NUMA nodes have memory ranges that span
1072 # other nodes. Even though a pfn is valid and
1073 # between a node's start and end pfns, it may not
1074 # reside on that node. See memmap_init_zone()
1076 config NODES_SPAN_OTHER_NODES
1078 depends on X86_64_ACPI_NUMA
1081 bool "NUMA emulation"
1082 depends on X86_64 && NUMA
1084 Enable NUMA emulation. A flat machine will be split
1085 into virtual nodes when booted with "numa=fake=N", where N is the
1086 number of nodes. This is only useful for debugging.
1089 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1091 default "9" if MAXSMP
1092 default "6" if X86_64
1093 default "4" if X86_NUMAQ
1095 depends on NEED_MULTIPLE_NODES
1097 Specify the maximum number of NUMA Nodes available on the target
1098 system. Increases memory reserved to accomodate various tables.
1100 config HAVE_ARCH_BOOTMEM_NODE
1102 depends on X86_32 && NUMA
1104 config ARCH_HAVE_MEMORY_PRESENT
1106 depends on X86_32 && DISCONTIGMEM
1108 config NEED_NODE_MEMMAP_SIZE
1110 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1112 config HAVE_ARCH_ALLOC_REMAP
1114 depends on X86_32 && NUMA
1116 config ARCH_FLATMEM_ENABLE
1118 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1120 config ARCH_DISCONTIGMEM_ENABLE
1122 depends on NUMA && X86_32
1124 config ARCH_DISCONTIGMEM_DEFAULT
1126 depends on NUMA && X86_32
1128 config ARCH_SPARSEMEM_DEFAULT
1132 config ARCH_SPARSEMEM_ENABLE
1134 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1135 select SPARSEMEM_STATIC if X86_32
1136 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1138 config ARCH_SELECT_MEMORY_MODEL
1140 depends on ARCH_SPARSEMEM_ENABLE
1142 config ARCH_MEMORY_PROBE
1144 depends on MEMORY_HOTPLUG
1149 bool "Allocate 3rd-level pagetables from highmem"
1150 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1152 The VM uses one page table entry for each page of physical memory.
1153 For systems with a lot of RAM, this can be wasteful of precious
1154 low memory. Setting this option will put user-space page table
1155 entries in high memory.
1157 config X86_CHECK_BIOS_CORRUPTION
1158 bool "Check for low memory corruption"
1160 Periodically check for memory corruption in low memory, which
1161 is suspected to be caused by BIOS. Even when enabled in the
1162 configuration, it is disabled at runtime. Enable it by
1163 setting "memory_corruption_check=1" on the kernel command
1164 line. By default it scans the low 64k of memory every 60
1165 seconds; see the memory_corruption_check_size and
1166 memory_corruption_check_period parameters in
1167 Documentation/kernel-parameters.txt to adjust this.
1169 When enabled with the default parameters, this option has
1170 almost no overhead, as it reserves a relatively small amount
1171 of memory and scans it infrequently. It both detects corruption
1172 and prevents it from affecting the running system.
1174 It is, however, intended as a diagnostic tool; if repeatable
1175 BIOS-originated corruption always affects the same memory,
1176 you can use memmap= to prevent the kernel from using that
1179 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1180 bool "Set the default setting of memory_corruption_check"
1181 depends on X86_CHECK_BIOS_CORRUPTION
1184 Set whether the default state of memory_corruption_check is
1187 config X86_RESERVE_LOW_64K
1188 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1191 Reserve the first 64K of physical RAM on BIOSes that are known
1192 to potentially corrupt that memory range. A numbers of BIOSes are
1193 known to utilize this area during suspend/resume, so it must not
1194 be used by the kernel.
1196 Set this to N if you are absolutely sure that you trust the BIOS
1197 to get all its memory reservations and usages right.
1199 If you have doubts about the BIOS (e.g. suspend/resume does not
1200 work or there's kernel crashes after certain hardware hotplug
1201 events) and it's not AMI or Phoenix, then you might want to enable
1202 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1203 corruption patterns.
1207 config MATH_EMULATION
1209 prompt "Math emulation" if X86_32
1211 Linux can emulate a math coprocessor (used for floating point
1212 operations) if you don't have one. 486DX and Pentium processors have
1213 a math coprocessor built in, 486SX and 386 do not, unless you added
1214 a 487DX or 387, respectively. (The messages during boot time can
1215 give you some hints here ["man dmesg"].) Everyone needs either a
1216 coprocessor or this emulation.
1218 If you don't have a math coprocessor, you need to say Y here; if you
1219 say Y here even though you have a coprocessor, the coprocessor will
1220 be used nevertheless. (This behavior can be changed with the kernel
1221 command line option "no387", which comes handy if your coprocessor
1222 is broken. Try "man bootparam" or see the documentation of your boot
1223 loader (lilo or loadlin) about how to pass options to the kernel at
1224 boot time.) This means that it is a good idea to say Y here if you
1225 intend to use this kernel on different machines.
1227 More information about the internals of the Linux math coprocessor
1228 emulation can be found in <file:arch/x86/math-emu/README>.
1230 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1231 kernel, it won't hurt.
1234 bool "MTRR (Memory Type Range Register) support"
1236 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1237 the Memory Type Range Registers (MTRRs) may be used to control
1238 processor access to memory ranges. This is most useful if you have
1239 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1240 allows bus write transfers to be combined into a larger transfer
1241 before bursting over the PCI/AGP bus. This can increase performance
1242 of image write operations 2.5 times or more. Saying Y here creates a
1243 /proc/mtrr file which may be used to manipulate your processor's
1244 MTRRs. Typically the X server should use this.
1246 This code has a reasonably generic interface so that similar
1247 control registers on other processors can be easily supported
1250 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1251 Registers (ARRs) which provide a similar functionality to MTRRs. For
1252 these, the ARRs are used to emulate the MTRRs.
1253 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1254 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1255 write-combining. All of these processors are supported by this code
1256 and it makes sense to say Y here if you have one of them.
1258 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1259 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1260 can lead to all sorts of problems, so it's good to say Y here.
1262 You can safely say Y even if your machine doesn't have MTRRs, you'll
1263 just add about 9 KB to your kernel.
1265 See <file:Documentation/x86/mtrr.txt> for more information.
1267 config MTRR_SANITIZER
1269 prompt "MTRR cleanup support"
1272 Convert MTRR layout from continuous to discrete, so X drivers can
1273 add writeback entries.
1275 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1276 The largest mtrr entry size for a continous block can be set with
1281 config MTRR_SANITIZER_ENABLE_DEFAULT
1282 int "MTRR cleanup enable value (0-1)"
1285 depends on MTRR_SANITIZER
1287 Enable mtrr cleanup default value
1289 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1290 int "MTRR cleanup spare reg num (0-7)"
1293 depends on MTRR_SANITIZER
1295 mtrr cleanup spare entries default, it can be changed via
1296 mtrr_spare_reg_nr=N on the kernel command line.
1300 prompt "x86 PAT support"
1303 Use PAT attributes to setup page level cache control.
1305 PATs are the modern equivalents of MTRRs and are much more
1306 flexible than MTRRs.
1308 Say N here if you see bootup problems (boot crash, boot hang,
1309 spontaneous reboots) or a non-working video driver.
1314 bool "EFI runtime service support"
1317 This enables the kernel to use EFI runtime services that are
1318 available (such as the EFI variable services).
1320 This option is only useful on systems that have EFI firmware.
1321 In addition, you should use the latest ELILO loader available
1322 at <http://elilo.sourceforge.net> in order to take advantage
1323 of EFI runtime services. However, even with this option, the
1324 resultant kernel should continue to boot on existing non-EFI
1329 prompt "Enable seccomp to safely compute untrusted bytecode"
1331 This kernel feature is useful for number crunching applications
1332 that may need to compute untrusted bytecode during their
1333 execution. By using pipes or other transports made available to
1334 the process as file descriptors supporting the read/write
1335 syscalls, it's possible to isolate those applications in
1336 their own address space using seccomp. Once seccomp is
1337 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1338 and the task is only allowed to execute a few safe syscalls
1339 defined by each seccomp mode.
1341 If unsure, say Y. Only embedded should say N here.
1343 config CC_STACKPROTECTOR
1344 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1345 depends on X86_64 && EXPERIMENTAL && BROKEN
1347 This option turns on the -fstack-protector GCC feature. This
1348 feature puts, at the beginning of critical functions, a canary
1349 value on the stack just before the return address, and validates
1350 the value just before actually returning. Stack based buffer
1351 overflows (that need to overwrite this return address) now also
1352 overwrite the canary, which gets detected and the attack is then
1353 neutralized via a kernel panic.
1355 This feature requires gcc version 4.2 or above, or a distribution
1356 gcc with the feature backported. Older versions are automatically
1357 detected and for those versions, this configuration option is ignored.
1359 config CC_STACKPROTECTOR_ALL
1360 bool "Use stack-protector for all functions"
1361 depends on CC_STACKPROTECTOR
1363 Normally, GCC only inserts the canary value protection for
1364 functions that use large-ish on-stack buffers. By enabling
1365 this option, GCC will be asked to do this for ALL functions.
1367 source kernel/Kconfig.hz
1370 bool "kexec system call"
1371 depends on X86_BIOS_REBOOT
1373 kexec is a system call that implements the ability to shutdown your
1374 current kernel, and to start another kernel. It is like a reboot
1375 but it is independent of the system firmware. And like a reboot
1376 you can start any kernel with it, not just Linux.
1378 The name comes from the similarity to the exec system call.
1380 It is an ongoing process to be certain the hardware in a machine
1381 is properly shutdown, so do not be surprised if this code does not
1382 initially work for you. It may help to enable device hotplugging
1383 support. As of this writing the exact hardware interface is
1384 strongly in flux, so no good recommendation can be made.
1387 bool "kernel crash dumps"
1388 depends on X86_64 || (X86_32 && HIGHMEM)
1390 Generate crash dump after being started by kexec.
1391 This should be normally only set in special crash dump kernels
1392 which are loaded in the main kernel with kexec-tools into
1393 a specially reserved region and then later executed after
1394 a crash by kdump/kexec. The crash dump kernel must be compiled
1395 to a memory address not used by the main kernel or BIOS using
1396 PHYSICAL_START, or it must be built as a relocatable image
1397 (CONFIG_RELOCATABLE=y).
1398 For more details see Documentation/kdump/kdump.txt
1401 bool "kexec jump (EXPERIMENTAL)"
1402 depends on EXPERIMENTAL
1403 depends on KEXEC && HIBERNATION && X86_32
1405 Jump between original kernel and kexeced kernel and invoke
1406 code in physical address mode via KEXEC
1408 config PHYSICAL_START
1409 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1410 default "0x1000000" if X86_NUMAQ
1411 default "0x200000" if X86_64
1414 This gives the physical address where the kernel is loaded.
1416 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1417 bzImage will decompress itself to above physical address and
1418 run from there. Otherwise, bzImage will run from the address where
1419 it has been loaded by the boot loader and will ignore above physical
1422 In normal kdump cases one does not have to set/change this option
1423 as now bzImage can be compiled as a completely relocatable image
1424 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1425 address. This option is mainly useful for the folks who don't want
1426 to use a bzImage for capturing the crash dump and want to use a
1427 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1428 to be specifically compiled to run from a specific memory area
1429 (normally a reserved region) and this option comes handy.
1431 So if you are using bzImage for capturing the crash dump, leave
1432 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1433 Otherwise if you plan to use vmlinux for capturing the crash dump
1434 change this value to start of the reserved region (Typically 16MB
1435 0x1000000). In other words, it can be set based on the "X" value as
1436 specified in the "crashkernel=YM@XM" command line boot parameter
1437 passed to the panic-ed kernel. Typically this parameter is set as
1438 crashkernel=64M@16M. Please take a look at
1439 Documentation/kdump/kdump.txt for more details about crash dumps.
1441 Usage of bzImage for capturing the crash dump is recommended as
1442 one does not have to build two kernels. Same kernel can be used
1443 as production kernel and capture kernel. Above option should have
1444 gone away after relocatable bzImage support is introduced. But it
1445 is present because there are users out there who continue to use
1446 vmlinux for dump capture. This option should go away down the
1449 Don't change this unless you know what you are doing.
1452 bool "Build a relocatable kernel (EXPERIMENTAL)"
1453 depends on EXPERIMENTAL
1455 This builds a kernel image that retains relocation information
1456 so it can be loaded someplace besides the default 1MB.
1457 The relocations tend to make the kernel binary about 10% larger,
1458 but are discarded at runtime.
1460 One use is for the kexec on panic case where the recovery kernel
1461 must live at a different physical address than the primary
1464 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1465 it has been loaded at and the compile time physical address
1466 (CONFIG_PHYSICAL_START) is ignored.
1468 config PHYSICAL_ALIGN
1470 prompt "Alignment value to which kernel should be aligned" if X86_32
1471 default "0x100000" if X86_32
1472 default "0x200000" if X86_64
1473 range 0x2000 0x400000
1475 This value puts the alignment restrictions on physical address
1476 where kernel is loaded and run from. Kernel is compiled for an
1477 address which meets above alignment restriction.
1479 If bootloader loads the kernel at a non-aligned address and
1480 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1481 address aligned to above value and run from there.
1483 If bootloader loads the kernel at a non-aligned address and
1484 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1485 load address and decompress itself to the address it has been
1486 compiled for and run from there. The address for which kernel is
1487 compiled already meets above alignment restrictions. Hence the
1488 end result is that kernel runs from a physical address meeting
1489 above alignment restrictions.
1491 Don't change this unless you know what you are doing.
1494 bool "Support for hot-pluggable CPUs"
1495 depends on SMP && HOTPLUG && !X86_VOYAGER
1497 Say Y here to allow turning CPUs off and on. CPUs can be
1498 controlled through /sys/devices/system/cpu.
1499 ( Note: power management support will enable this option
1500 automatically on SMP systems. )
1501 Say N if you want to disable CPU hotplug.
1505 prompt "Compat VDSO support"
1506 depends on X86_32 || IA32_EMULATION
1508 Map the 32-bit VDSO to the predictable old-style address too.
1510 Say N here if you are running a sufficiently recent glibc
1511 version (2.3.3 or later), to remove the high-mapped
1512 VDSO mapping and to exclusively use the randomized VDSO.
1517 bool "Built-in kernel command line"
1520 Allow for specifying boot arguments to the kernel at
1521 build time. On some systems (e.g. embedded ones), it is
1522 necessary or convenient to provide some or all of the
1523 kernel boot arguments with the kernel itself (that is,
1524 to not rely on the boot loader to provide them.)
1526 To compile command line arguments into the kernel,
1527 set this option to 'Y', then fill in the
1528 the boot arguments in CONFIG_CMDLINE.
1530 Systems with fully functional boot loaders (i.e. non-embedded)
1531 should leave this option set to 'N'.
1534 string "Built-in kernel command string"
1535 depends on CMDLINE_BOOL
1538 Enter arguments here that should be compiled into the kernel
1539 image and used at boot time. If the boot loader provides a
1540 command line at boot time, it is appended to this string to
1541 form the full kernel command line, when the system boots.
1543 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1544 change this behavior.
1546 In most cases, the command line (whether built-in or provided
1547 by the boot loader) should specify the device for the root
1550 config CMDLINE_OVERRIDE
1551 bool "Built-in command line overrides boot loader arguments"
1553 depends on CMDLINE_BOOL
1555 Set this option to 'Y' to have the kernel ignore the boot loader
1556 command line, and use ONLY the built-in command line.
1558 This is used to work around broken boot loaders. This should
1559 be set to 'N' under normal conditions.
1563 config ARCH_ENABLE_MEMORY_HOTPLUG
1565 depends on X86_64 || (X86_32 && HIGHMEM)
1567 config ARCH_ENABLE_MEMORY_HOTREMOVE
1569 depends on MEMORY_HOTPLUG
1571 config HAVE_ARCH_EARLY_PFN_TO_NID
1575 menu "Power management and ACPI options"
1576 depends on !X86_VOYAGER
1578 config ARCH_HIBERNATION_HEADER
1580 depends on X86_64 && HIBERNATION
1582 source "kernel/power/Kconfig"
1584 source "drivers/acpi/Kconfig"
1589 depends on APM || APM_MODULE
1592 tristate "APM (Advanced Power Management) BIOS support"
1593 depends on X86_32 && PM_SLEEP
1595 APM is a BIOS specification for saving power using several different
1596 techniques. This is mostly useful for battery powered laptops with
1597 APM compliant BIOSes. If you say Y here, the system time will be
1598 reset after a RESUME operation, the /proc/apm device will provide
1599 battery status information, and user-space programs will receive
1600 notification of APM "events" (e.g. battery status change).
1602 If you select "Y" here, you can disable actual use of the APM
1603 BIOS by passing the "apm=off" option to the kernel at boot time.
1605 Note that the APM support is almost completely disabled for
1606 machines with more than one CPU.
1608 In order to use APM, you will need supporting software. For location
1609 and more information, read <file:Documentation/power/pm.txt> and the
1610 Battery Powered Linux mini-HOWTO, available from
1611 <http://www.tldp.org/docs.html#howto>.
1613 This driver does not spin down disk drives (see the hdparm(8)
1614 manpage ("man 8 hdparm") for that), and it doesn't turn off
1615 VESA-compliant "green" monitors.
1617 This driver does not support the TI 4000M TravelMate and the ACER
1618 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1619 desktop machines also don't have compliant BIOSes, and this driver
1620 may cause those machines to panic during the boot phase.
1622 Generally, if you don't have a battery in your machine, there isn't
1623 much point in using this driver and you should say N. If you get
1624 random kernel OOPSes or reboots that don't seem to be related to
1625 anything, try disabling/enabling this option (or disabling/enabling
1628 Some other things you should try when experiencing seemingly random,
1631 1) make sure that you have enough swap space and that it is
1633 2) pass the "no-hlt" option to the kernel
1634 3) switch on floating point emulation in the kernel and pass
1635 the "no387" option to the kernel
1636 4) pass the "floppy=nodma" option to the kernel
1637 5) pass the "mem=4M" option to the kernel (thereby disabling
1638 all but the first 4 MB of RAM)
1639 6) make sure that the CPU is not over clocked.
1640 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1641 8) disable the cache from your BIOS settings
1642 9) install a fan for the video card or exchange video RAM
1643 10) install a better fan for the CPU
1644 11) exchange RAM chips
1645 12) exchange the motherboard.
1647 To compile this driver as a module, choose M here: the
1648 module will be called apm.
1652 config APM_IGNORE_USER_SUSPEND
1653 bool "Ignore USER SUSPEND"
1655 This option will ignore USER SUSPEND requests. On machines with a
1656 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1657 series notebooks, it is necessary to say Y because of a BIOS bug.
1659 config APM_DO_ENABLE
1660 bool "Enable PM at boot time"
1662 Enable APM features at boot time. From page 36 of the APM BIOS
1663 specification: "When disabled, the APM BIOS does not automatically
1664 power manage devices, enter the Standby State, enter the Suspend
1665 State, or take power saving steps in response to CPU Idle calls."
1666 This driver will make CPU Idle calls when Linux is idle (unless this
1667 feature is turned off -- see "Do CPU IDLE calls", below). This
1668 should always save battery power, but more complicated APM features
1669 will be dependent on your BIOS implementation. You may need to turn
1670 this option off if your computer hangs at boot time when using APM
1671 support, or if it beeps continuously instead of suspending. Turn
1672 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1673 T400CDT. This is off by default since most machines do fine without
1677 bool "Make CPU Idle calls when idle"
1679 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1680 On some machines, this can activate improved power savings, such as
1681 a slowed CPU clock rate, when the machine is idle. These idle calls
1682 are made after the idle loop has run for some length of time (e.g.,
1683 333 mS). On some machines, this will cause a hang at boot time or
1684 whenever the CPU becomes idle. (On machines with more than one CPU,
1685 this option does nothing.)
1687 config APM_DISPLAY_BLANK
1688 bool "Enable console blanking using APM"
1690 Enable console blanking using the APM. Some laptops can use this to
1691 turn off the LCD backlight when the screen blanker of the Linux
1692 virtual console blanks the screen. Note that this is only used by
1693 the virtual console screen blanker, and won't turn off the backlight
1694 when using the X Window system. This also doesn't have anything to
1695 do with your VESA-compliant power-saving monitor. Further, this
1696 option doesn't work for all laptops -- it might not turn off your
1697 backlight at all, or it might print a lot of errors to the console,
1698 especially if you are using gpm.
1700 config APM_ALLOW_INTS
1701 bool "Allow interrupts during APM BIOS calls"
1703 Normally we disable external interrupts while we are making calls to
1704 the APM BIOS as a measure to lessen the effects of a badly behaving
1705 BIOS implementation. The BIOS should reenable interrupts if it
1706 needs to. Unfortunately, some BIOSes do not -- especially those in
1707 many of the newer IBM Thinkpads. If you experience hangs when you
1708 suspend, try setting this to Y. Otherwise, say N.
1712 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1714 source "drivers/cpuidle/Kconfig"
1716 source "drivers/idle/Kconfig"
1721 menu "Bus options (PCI etc.)"
1726 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1728 Find out whether you have a PCI motherboard. PCI is the name of a
1729 bus system, i.e. the way the CPU talks to the other stuff inside
1730 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1731 VESA. If you have PCI, say Y, otherwise N.
1734 prompt "PCI access mode"
1735 depends on X86_32 && PCI
1738 On PCI systems, the BIOS can be used to detect the PCI devices and
1739 determine their configuration. However, some old PCI motherboards
1740 have BIOS bugs and may crash if this is done. Also, some embedded
1741 PCI-based systems don't have any BIOS at all. Linux can also try to
1742 detect the PCI hardware directly without using the BIOS.
1744 With this option, you can specify how Linux should detect the
1745 PCI devices. If you choose "BIOS", the BIOS will be used,
1746 if you choose "Direct", the BIOS won't be used, and if you
1747 choose "MMConfig", then PCI Express MMCONFIG will be used.
1748 If you choose "Any", the kernel will try MMCONFIG, then the
1749 direct access method and falls back to the BIOS if that doesn't
1750 work. If unsure, go with the default, which is "Any".
1755 config PCI_GOMMCONFIG
1772 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1774 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1777 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1781 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1785 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1792 bool "Support mmconfig PCI config space access"
1793 depends on X86_64 && PCI && ACPI
1796 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1797 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1799 DMA remapping (DMAR) devices support enables independent address
1800 translations for Direct Memory Access (DMA) from devices.
1801 These DMA remapping devices are reported via ACPI tables
1802 and include PCI device scope covered by these DMA
1805 config DMAR_DEFAULT_ON
1807 prompt "Enable DMA Remapping Devices by default"
1810 Selecting this option will enable a DMAR device at boot time if
1811 one is found. If this option is not selected, DMAR support can
1812 be enabled by passing intel_iommu=on to the kernel. It is
1813 recommended you say N here while the DMAR code remains
1818 prompt "Support for Graphics workaround"
1821 Current Graphics drivers tend to use physical address
1822 for DMA and avoid using DMA APIs. Setting this config
1823 option permits the IOMMU driver to set a unity map for
1824 all the OS-visible memory. Hence the driver can continue
1825 to use physical addresses for DMA.
1827 config DMAR_FLOPPY_WA
1831 Floppy disk drivers are know to bypass DMA API calls
1832 thereby failing to work when IOMMU is enabled. This
1833 workaround will setup a 1:1 mapping for the first
1834 16M to make floppy (an ISA device) work.
1837 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1838 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1840 Supports Interrupt remapping for IO-APIC and MSI devices.
1841 To use x2apic mode in the CPU's which support x2APIC enhancements or
1842 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1844 source "drivers/pci/pcie/Kconfig"
1846 source "drivers/pci/Kconfig"
1848 # x86_64 have no ISA slots, but do have ISA-style DMA.
1856 depends on !X86_VOYAGER
1858 Find out whether you have ISA slots on your motherboard. ISA is the
1859 name of a bus system, i.e. the way the CPU talks to the other stuff
1860 inside your box. Other bus systems are PCI, EISA, MicroChannel
1861 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1862 newer boards don't support it. If you have ISA, say Y, otherwise N.
1868 The Extended Industry Standard Architecture (EISA) bus was
1869 developed as an open alternative to the IBM MicroChannel bus.
1871 The EISA bus provided some of the features of the IBM MicroChannel
1872 bus while maintaining backward compatibility with cards made for
1873 the older ISA bus. The EISA bus saw limited use between 1988 and
1874 1995 when it was made obsolete by the PCI bus.
1876 Say Y here if you are building a kernel for an EISA-based machine.
1880 source "drivers/eisa/Kconfig"
1883 bool "MCA support" if !X86_VOYAGER
1884 default y if X86_VOYAGER
1886 MicroChannel Architecture is found in some IBM PS/2 machines and
1887 laptops. It is a bus system similar to PCI or ISA. See
1888 <file:Documentation/mca.txt> (and especially the web page given
1889 there) before attempting to build an MCA bus kernel.
1891 source "drivers/mca/Kconfig"
1894 tristate "NatSemi SCx200 support"
1895 depends on !X86_VOYAGER
1897 This provides basic support for National Semiconductor's
1898 (now AMD's) Geode processors. The driver probes for the
1899 PCI-IDs of several on-chip devices, so its a good dependency
1900 for other scx200_* drivers.
1902 If compiled as a module, the driver is named scx200.
1904 config SCx200HR_TIMER
1905 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1906 depends on SCx200 && GENERIC_TIME
1909 This driver provides a clocksource built upon the on-chip
1910 27MHz high-resolution timer. Its also a workaround for
1911 NSC Geode SC-1100's buggy TSC, which loses time when the
1912 processor goes idle (as is done by the scheduler). The
1913 other workaround is idle=poll boot option.
1915 config GEODE_MFGPT_TIMER
1917 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1918 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1920 This driver provides a clock event source based on the MFGPT
1921 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1922 MFGPTs have a better resolution and max interval than the
1923 generic PIT, and are suitable for use as high-res timers.
1926 bool "One Laptop Per Child support"
1929 Add support for detecting the unique features of the OLPC
1936 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1938 source "drivers/pcmcia/Kconfig"
1940 source "drivers/pci/hotplug/Kconfig"
1945 menu "Executable file formats / Emulations"
1947 source "fs/Kconfig.binfmt"
1949 config IA32_EMULATION
1950 bool "IA32 Emulation"
1952 select COMPAT_BINFMT_ELF
1954 Include code to run 32-bit programs under a 64-bit kernel. You should
1955 likely turn this on, unless you're 100% sure that you don't have any
1956 32-bit programs left.
1959 tristate "IA32 a.out support"
1960 depends on IA32_EMULATION
1962 Support old a.out binaries in the 32bit emulation.
1966 depends on IA32_EMULATION
1968 config COMPAT_FOR_U64_ALIGNMENT
1972 config SYSVIPC_COMPAT
1974 depends on COMPAT && SYSVIPC
1979 config HAVE_ATOMIC_IOMAP
1983 source "net/Kconfig"
1985 source "drivers/Kconfig"
1987 source "drivers/firmware/Kconfig"
1991 source "arch/x86/Kconfig.debug"
1993 source "security/Kconfig"
1995 source "crypto/Kconfig"
1997 source "arch/x86/kvm/Kconfig"
1999 source "lib/Kconfig"
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