2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
39 select HAVE_ARCH_KGDB if !X86_VOYAGER
40 select HAVE_ARCH_TRACEHOOK
41 select HAVE_GENERIC_DMA_COHERENT if X86_32
42 select HAVE_EFFICIENT_UNALIGNED_ACCESS
43 select USER_STACKTRACE_SUPPORT
47 default "arch/x86/configs/i386_defconfig" if X86_32
48 default "arch/x86/configs/x86_64_defconfig" if X86_64
53 config GENERIC_CMOS_UPDATE
56 config CLOCKSOURCE_WATCHDOG
59 config GENERIC_CLOCKEVENTS
62 config GENERIC_CLOCKEVENTS_BROADCAST
64 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
66 config LOCKDEP_SUPPORT
69 config STACKTRACE_SUPPORT
72 config HAVE_LATENCYTOP_SUPPORT
75 config FAST_CMPXCHG_LOCAL
88 config GENERIC_ISA_DMA
97 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
99 config GENERIC_BUG_RELATIVE_POINTERS
102 config GENERIC_HWEIGHT
108 config ARCH_MAY_HAVE_PC_FDC
111 config RWSEM_GENERIC_SPINLOCK
114 config RWSEM_XCHGADD_ALGORITHM
117 config ARCH_HAS_CPU_IDLE_WAIT
120 config GENERIC_CALIBRATE_DELAY
123 config GENERIC_TIME_VSYSCALL
127 config ARCH_HAS_CPU_RELAX
130 config ARCH_HAS_DEFAULT_IDLE
133 config ARCH_HAS_CACHE_LINE_SIZE
136 config HAVE_SETUP_PER_CPU_AREA
137 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
139 config HAVE_CPUMASK_OF_CPU_MAP
142 config ARCH_HIBERNATION_POSSIBLE
144 depends on !SMP || !X86_VOYAGER
146 config ARCH_SUSPEND_POSSIBLE
148 depends on !X86_VOYAGER
154 config ARCH_POPULATES_NODE_MAP
161 config ARCH_SUPPORTS_OPTIMIZED_INLINING
164 # Use the generic interrupt handling code in kernel/irq/:
165 config GENERIC_HARDIRQS
169 config GENERIC_IRQ_PROBE
173 config GENERIC_PENDING_IRQ
175 depends on GENERIC_HARDIRQS && SMP
180 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
183 config USE_GENERIC_SMP_HELPERS
189 depends on X86_32 && SMP
193 depends on X86_64 && SMP
198 depends on (X86_32 && !X86_VOYAGER) || X86_64
201 config X86_BIOS_REBOOT
203 depends on !X86_VOYAGER
206 config X86_TRAMPOLINE
208 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
213 source "init/Kconfig"
214 source "kernel/Kconfig.freezer"
216 menu "Processor type and features"
218 source "kernel/time/Kconfig"
221 bool "Symmetric multi-processing support"
223 This enables support for systems with more than one CPU. If you have
224 a system with only one CPU, like most personal computers, say N. If
225 you have a system with more than one CPU, say Y.
227 If you say N here, the kernel will run on single and multiprocessor
228 machines, but will use only one CPU of a multiprocessor machine. If
229 you say Y here, the kernel will run on many, but not all,
230 singleprocessor machines. On a singleprocessor machine, the kernel
231 will run faster if you say N here.
233 Note that if you say Y here and choose architecture "586" or
234 "Pentium" under "Processor family", the kernel will not work on 486
235 architectures. Similarly, multiprocessor kernels for the "PPro"
236 architecture may not work on all Pentium based boards.
238 People using multiprocessor machines who say Y here should also say
239 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
240 Management" code will be disabled if you say Y here.
242 See also <file:Documentation/i386/IO-APIC.txt>,
243 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
244 <http://www.tldp.org/docs.html#howto>.
246 If you don't know what to do here, say N.
248 config X86_HAS_BOOT_CPU_ID
250 depends on X86_VOYAGER
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.
274 config X86_FIND_SMP_CONFIG
276 depends on X86_MPPARSE || X86_VOYAGER
279 bool "Enable MPS table" if ACPI
281 depends on X86_LOCAL_APIC
283 For old smp systems that do not have proper acpi support. Newer systems
284 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
287 prompt "Subarchitecture Type"
293 Choose this option if your computer is a standard PC or compatible.
299 Select this for an AMD Elan processor.
301 Do not use this option for K6/Athlon/Opteron processors!
303 If unsure, choose "PC-compatible" instead.
307 depends on X86_32 && (SMP || BROKEN) && !PCI
309 Voyager is an MCA-based 32-way capable SMP architecture proprietary
310 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
314 If you do not specifically know you have a Voyager based machine,
315 say N here, otherwise the kernel you build will not be bootable.
317 config X86_GENERICARCH
318 bool "Generic architecture"
321 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
322 subarchitectures. It is intended for a generic binary kernel.
323 if you select them all, kernel will probe it one by one. and will
329 bool "NUMAQ (IBM/Sequent)"
330 depends on SMP && X86_32 && PCI && X86_MPPARSE
333 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
334 NUMA multiquad box. This changes the way that processors are
335 bootstrapped, and uses Clustered Logical APIC addressing mode instead
336 of Flat Logical. You will need a new lynxer.elf file to flash your
337 firmware with - send email to <Martin.Bligh@us.ibm.com>.
340 bool "Summit/EXA (IBM x440)"
341 depends on X86_32 && SMP
343 This option is needed for IBM systems that use the Summit/EXA chipset.
344 In particular, it is needed for the x440.
347 bool "Support for Unisys ES7000 IA32 series"
348 depends on X86_32 && SMP
350 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
351 supposed to run on an IA32-based Unisys ES7000 system.
354 bool "Support for big SMP systems with more than 8 CPUs"
355 depends on X86_32 && SMP
357 This option is needed for the systems that have more than 8 CPUs
358 and if the system is not of any sub-arch type above.
363 bool "Support for ScaleMP vSMP"
365 depends on X86_64 && PCI
367 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
368 supposed to run on these EM64T-based machines. Only choose this option
369 if you have one of these machines.
374 bool "SGI 320/540 (Visual Workstation)"
375 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
377 The SGI Visual Workstation series is an IA32-based workstation
378 based on SGI systems chips with some legacy PC hardware attached.
380 Say Y here to create a kernel to run on the SGI 320 or 540.
382 A kernel compiled for the Visual Workstation will run on general
383 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
386 bool "RDC R-321x SoC"
389 select X86_REBOOTFIXUPS
391 This option is needed for RDC R-321x system-on-chip, also known
393 If you don't have one of these chips, you should say N here.
395 config SCHED_OMIT_FRAME_POINTER
397 prompt "Single-depth WCHAN output"
400 Calculate simpler /proc/<PID>/wchan values. If this option
401 is disabled then wchan values will recurse back to the
402 caller function. This provides more accurate wchan values,
403 at the expense of slightly more scheduling overhead.
405 If in doubt, say "Y".
407 menuconfig PARAVIRT_GUEST
408 bool "Paravirtualized guest support"
410 Say Y here to get to see options related to running Linux under
411 various hypervisors. This option alone does not add any kernel code.
413 If you say N, all options in this submenu will be skipped and disabled.
417 source "arch/x86/xen/Kconfig"
420 bool "VMI Guest support"
423 depends on !X86_VOYAGER
425 VMI provides a paravirtualized interface to the VMware ESX server
426 (it could be used by other hypervisors in theory too, but is not
427 at the moment), by linking the kernel to a GPL-ed ROM module
428 provided by the hypervisor.
431 bool "KVM paravirtualized clock"
433 select PARAVIRT_CLOCK
434 depends on !X86_VOYAGER
436 Turning on this option will allow you to run a paravirtualized clock
437 when running over the KVM hypervisor. Instead of relying on a PIT
438 (or probably other) emulation by the underlying device model, the host
439 provides the guest with timing infrastructure such as time of day, and
443 bool "KVM Guest support"
445 depends on !X86_VOYAGER
447 This option enables various optimizations for running under the KVM
450 source "arch/x86/lguest/Kconfig"
453 bool "Enable paravirtualization code"
454 depends on !X86_VOYAGER
456 This changes the kernel so it can modify itself when it is run
457 under a hypervisor, potentially improving performance significantly
458 over full virtualization. However, when run without a hypervisor
459 the kernel is theoretically slower and slightly larger.
461 config PARAVIRT_CLOCK
467 config PARAVIRT_DEBUG
468 bool "paravirt-ops debugging"
469 depends on PARAVIRT && DEBUG_KERNEL
471 Enable to debug paravirt_ops internals. Specifically, BUG if
472 a paravirt_op is missing when it is called.
477 This option adds a kernel parameter 'memtest', which allows memtest
479 memtest=0, mean disabled; -- default
480 memtest=1, mean do 1 test pattern;
482 memtest=4, mean do 4 test patterns.
483 If you are unsure how to answer this question, answer N.
485 config X86_SUMMIT_NUMA
487 depends on X86_32 && NUMA && X86_GENERICARCH
489 config X86_CYCLONE_TIMER
491 depends on X86_GENERICARCH
493 source "arch/x86/Kconfig.cpu"
497 prompt "HPET Timer Support" if X86_32
499 Use the IA-PC HPET (High Precision Event Timer) to manage
500 time in preference to the PIT and RTC, if a HPET is
502 HPET is the next generation timer replacing legacy 8254s.
503 The HPET provides a stable time base on SMP
504 systems, unlike the TSC, but it is more expensive to access,
505 as it is off-chip. You can find the HPET spec at
506 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
508 You can safely choose Y here. However, HPET will only be
509 activated if the platform and the BIOS support this feature.
510 Otherwise the 8254 will be used for timing services.
512 Choose N to continue using the legacy 8254 timer.
514 config HPET_EMULATE_RTC
516 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
518 # Mark as embedded because too many people got it wrong.
519 # The code disables itself when not needed.
522 bool "Enable DMI scanning" if EMBEDDED
524 Enabled scanning of DMI to identify machine quirks. Say Y
525 here unless you have verified that your setup is not
526 affected by entries in the DMI blacklist. Required by PNP
530 bool "GART IOMMU support" if EMBEDDED
534 depends on X86_64 && PCI
536 Support for full DMA access of devices with 32bit memory access only
537 on systems with more than 3GB. This is usually needed for USB,
538 sound, many IDE/SATA chipsets and some other devices.
539 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
540 based hardware IOMMU and a software bounce buffer based IOMMU used
541 on Intel systems and as fallback.
542 The code is only active when needed (enough memory and limited
543 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
547 bool "IBM Calgary IOMMU support"
549 depends on X86_64 && PCI && EXPERIMENTAL
551 Support for hardware IOMMUs in IBM's xSeries x366 and x460
552 systems. Needed to run systems with more than 3GB of memory
553 properly with 32-bit PCI devices that do not support DAC
554 (Double Address Cycle). Calgary also supports bus level
555 isolation, where all DMAs pass through the IOMMU. This
556 prevents them from going anywhere except their intended
557 destination. This catches hard-to-find kernel bugs and
558 mis-behaving drivers and devices that do not use the DMA-API
559 properly to set up their DMA buffers. The IOMMU can be
560 turned off at boot time with the iommu=off parameter.
561 Normally the kernel will make the right choice by itself.
564 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
566 prompt "Should Calgary be enabled by default?"
567 depends on CALGARY_IOMMU
569 Should Calgary be enabled by default? if you choose 'y', Calgary
570 will be used (if it exists). If you choose 'n', Calgary will not be
571 used even if it exists. If you choose 'n' and would like to use
572 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
576 bool "AMD IOMMU support"
579 depends on X86_64 && PCI && ACPI
581 With this option you can enable support for AMD IOMMU hardware in
582 your system. An IOMMU is a hardware component which provides
583 remapping of DMA memory accesses from devices. With an AMD IOMMU you
584 can isolate the the DMA memory of different devices and protect the
585 system from misbehaving device drivers or hardware.
587 You can find out if your system has an AMD IOMMU if you look into
588 your BIOS for an option to enable it or if you have an IVRS ACPI
591 config AMD_IOMMU_STATS
592 bool "Export AMD IOMMU statistics to debugfs"
596 This option enables code in the AMD IOMMU driver to collect various
597 statistics about whats happening in the driver and exports that
598 information to userspace via debugfs.
601 # need this always selected by IOMMU for the VIA workaround
605 Support for software bounce buffers used on x86-64 systems
606 which don't have a hardware IOMMU (e.g. the current generation
607 of Intel's x86-64 CPUs). Using this PCI devices which can only
608 access 32-bits of memory can be used on systems with more than
609 3 GB of memory. If unsure, say Y.
612 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
615 def_bool (AMD_IOMMU || DMAR)
618 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
619 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
620 select CPUMASK_OFFSTACK
623 Configure maximum number of CPUS and NUMA Nodes for this architecture.
627 int "Maximum number of CPUs" if SMP && !MAXSMP
628 range 2 512 if SMP && !MAXSMP
630 default "4096" if MAXSMP
631 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
634 This allows you to specify the maximum number of CPUs which this
635 kernel will support. The maximum supported value is 512 and the
636 minimum value which makes sense is 2.
638 This is purely to save memory - each supported CPU adds
639 approximately eight kilobytes to the kernel image.
642 bool "SMT (Hyperthreading) scheduler support"
645 SMT scheduler support improves the CPU scheduler's decision making
646 when dealing with Intel Pentium 4 chips with HyperThreading at a
647 cost of slightly increased overhead in some places. If unsure say
652 prompt "Multi-core scheduler support"
655 Multi-core scheduler support improves the CPU scheduler's decision
656 making when dealing with multi-core CPU chips at a cost of slightly
657 increased overhead in some places. If unsure say N here.
659 source "kernel/Kconfig.preempt"
662 bool "Local APIC support on uniprocessors"
663 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
665 A local APIC (Advanced Programmable Interrupt Controller) is an
666 integrated interrupt controller in the CPU. If you have a single-CPU
667 system which has a processor with a local APIC, you can say Y here to
668 enable and use it. If you say Y here even though your machine doesn't
669 have a local APIC, then the kernel will still run with no slowdown at
670 all. The local APIC supports CPU-generated self-interrupts (timer,
671 performance counters), and the NMI watchdog which detects hard
675 bool "IO-APIC support on uniprocessors"
676 depends on X86_UP_APIC
678 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
679 SMP-capable replacement for PC-style interrupt controllers. Most
680 SMP systems and many recent uniprocessor systems have one.
682 If you have a single-CPU system with an IO-APIC, you can say Y here
683 to use it. If you say Y here even though your machine doesn't have
684 an IO-APIC, then the kernel will still run with no slowdown at all.
686 config X86_LOCAL_APIC
688 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
692 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
694 config X86_VISWS_APIC
696 depends on X86_32 && X86_VISWS
698 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
699 bool "Reroute for broken boot IRQs"
701 depends on X86_IO_APIC
703 This option enables a workaround that fixes a source of
704 spurious interrupts. This is recommended when threaded
705 interrupt handling is used on systems where the generation of
706 superfluous "boot interrupts" cannot be disabled.
708 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
709 entry in the chipset's IO-APIC is masked (as, e.g. the RT
710 kernel does during interrupt handling). On chipsets where this
711 boot IRQ generation cannot be disabled, this workaround keeps
712 the original IRQ line masked so that only the equivalent "boot
713 IRQ" is delivered to the CPUs. The workaround also tells the
714 kernel to set up the IRQ handler on the boot IRQ line. In this
715 way only one interrupt is delivered to the kernel. Otherwise
716 the spurious second interrupt may cause the kernel to bring
717 down (vital) interrupt lines.
719 Only affects "broken" chipsets. Interrupt sharing may be
720 increased on these systems.
723 bool "Machine Check Exception"
724 depends on !X86_VOYAGER
726 Machine Check Exception support allows the processor to notify the
727 kernel if it detects a problem (e.g. overheating, component failure).
728 The action the kernel takes depends on the severity of the problem,
729 ranging from a warning message on the console, to halting the machine.
730 Your processor must be a Pentium or newer to support this - check the
731 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
732 have a design flaw which leads to false MCE events - hence MCE is
733 disabled on all P5 processors, unless explicitly enabled with "mce"
734 as a boot argument. Similarly, if MCE is built in and creates a
735 problem on some new non-standard machine, you can boot with "nomce"
736 to disable it. MCE support simply ignores non-MCE processors like
737 the 386 and 486, so nearly everyone can say Y here.
741 prompt "Intel MCE features"
742 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
744 Additional support for intel specific MCE features such as
749 prompt "AMD MCE features"
750 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
752 Additional support for AMD specific MCE features such as
753 the DRAM Error Threshold.
755 config X86_MCE_NONFATAL
756 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
757 depends on X86_32 && X86_MCE
759 Enabling this feature starts a timer that triggers every 5 seconds which
760 will look at the machine check registers to see if anything happened.
761 Non-fatal problems automatically get corrected (but still logged).
762 Disable this if you don't want to see these messages.
763 Seeing the messages this option prints out may be indicative of dying
764 or out-of-spec (ie, overclocked) hardware.
765 This option only does something on certain CPUs.
766 (AMD Athlon/Duron and Intel Pentium 4)
768 config X86_MCE_P4THERMAL
769 bool "check for P4 thermal throttling interrupt."
770 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
772 Enabling this feature will cause a message to be printed when the P4
773 enters thermal throttling.
776 bool "Enable VM86 support" if EMBEDDED
780 This option is required by programs like DOSEMU to run 16-bit legacy
781 code on X86 processors. It also may be needed by software like
782 XFree86 to initialize some video cards via BIOS. Disabling this
783 option saves about 6k.
786 tristate "Toshiba Laptop support"
789 This adds a driver to safely access the System Management Mode of
790 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
791 not work on models with a Phoenix BIOS. The System Management Mode
792 is used to set the BIOS and power saving options on Toshiba portables.
794 For information on utilities to make use of this driver see the
795 Toshiba Linux utilities web site at:
796 <http://www.buzzard.org.uk/toshiba/>.
798 Say Y if you intend to run this kernel on a Toshiba portable.
802 tristate "Dell laptop support"
804 This adds a driver to safely access the System Management Mode
805 of the CPU on the Dell Inspiron 8000. The System Management Mode
806 is used to read cpu temperature and cooling fan status and to
807 control the fans on the I8K portables.
809 This driver has been tested only on the Inspiron 8000 but it may
810 also work with other Dell laptops. You can force loading on other
811 models by passing the parameter `force=1' to the module. Use at
814 For information on utilities to make use of this driver see the
815 I8K Linux utilities web site at:
816 <http://people.debian.org/~dz/i8k/>
818 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
821 config X86_REBOOTFIXUPS
822 bool "Enable X86 board specific fixups for reboot"
825 This enables chipset and/or board specific fixups to be done
826 in order to get reboot to work correctly. This is only needed on
827 some combinations of hardware and BIOS. The symptom, for which
828 this config is intended, is when reboot ends with a stalled/hung
831 Currently, the only fixup is for the Geode machines using
832 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
834 Say Y if you want to enable the fixup. Currently, it's safe to
835 enable this option even if you don't need it.
839 tristate "/dev/cpu/microcode - microcode support"
842 If you say Y here, you will be able to update the microcode on
843 certain Intel and AMD processors. The Intel support is for the
844 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
845 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
846 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
847 You will obviously need the actual microcode binary data itself
848 which is not shipped with the Linux kernel.
850 This option selects the general module only, you need to select
851 at least one vendor specific module as well.
853 To compile this driver as a module, choose M here: the
854 module will be called microcode.
856 config MICROCODE_INTEL
857 bool "Intel microcode patch loading support"
862 This options enables microcode patch loading support for Intel
865 For latest news and information on obtaining all the required
866 Intel ingredients for this driver, check:
867 <http://www.urbanmyth.org/microcode/>.
870 bool "AMD microcode patch loading support"
874 If you select this option, microcode patch loading support for AMD
875 processors will be enabled.
877 config MICROCODE_OLD_INTERFACE
882 tristate "/dev/cpu/*/msr - Model-specific register support"
884 This device gives privileged processes access to the x86
885 Model-Specific Registers (MSRs). It is a character device with
886 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
887 MSR accesses are directed to a specific CPU on multi-processor
891 tristate "/dev/cpu/*/cpuid - CPU information support"
893 This device gives processes access to the x86 CPUID instruction to
894 be executed on a specific processor. It is a character device
895 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
899 prompt "High Memory Support"
900 default HIGHMEM4G if !X86_NUMAQ
901 default HIGHMEM64G if X86_NUMAQ
906 depends on !X86_NUMAQ
908 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
909 However, the address space of 32-bit x86 processors is only 4
910 Gigabytes large. That means that, if you have a large amount of
911 physical memory, not all of it can be "permanently mapped" by the
912 kernel. The physical memory that's not permanently mapped is called
915 If you are compiling a kernel which will never run on a machine with
916 more than 1 Gigabyte total physical RAM, answer "off" here (default
917 choice and suitable for most users). This will result in a "3GB/1GB"
918 split: 3GB are mapped so that each process sees a 3GB virtual memory
919 space and the remaining part of the 4GB virtual memory space is used
920 by the kernel to permanently map as much physical memory as
923 If the machine has between 1 and 4 Gigabytes physical RAM, then
926 If more than 4 Gigabytes is used then answer "64GB" here. This
927 selection turns Intel PAE (Physical Address Extension) mode on.
928 PAE implements 3-level paging on IA32 processors. PAE is fully
929 supported by Linux, PAE mode is implemented on all recent Intel
930 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
931 then the kernel will not boot on CPUs that don't support PAE!
933 The actual amount of total physical memory will either be
934 auto detected or can be forced by using a kernel command line option
935 such as "mem=256M". (Try "man bootparam" or see the documentation of
936 your boot loader (lilo or loadlin) about how to pass options to the
937 kernel at boot time.)
939 If unsure, say "off".
943 depends on !X86_NUMAQ
945 Select this if you have a 32-bit processor and between 1 and 4
946 gigabytes of physical RAM.
950 depends on !M386 && !M486
953 Select this if you have a 32-bit processor and more than 4
954 gigabytes of physical RAM.
959 depends on EXPERIMENTAL
960 prompt "Memory split" if EMBEDDED
964 Select the desired split between kernel and user memory.
966 If the address range available to the kernel is less than the
967 physical memory installed, the remaining memory will be available
968 as "high memory". Accessing high memory is a little more costly
969 than low memory, as it needs to be mapped into the kernel first.
970 Note that increasing the kernel address space limits the range
971 available to user programs, making the address space there
972 tighter. Selecting anything other than the default 3G/1G split
973 will also likely make your kernel incompatible with binary-only
976 If you are not absolutely sure what you are doing, leave this
980 bool "3G/1G user/kernel split"
981 config VMSPLIT_3G_OPT
983 bool "3G/1G user/kernel split (for full 1G low memory)"
985 bool "2G/2G user/kernel split"
986 config VMSPLIT_2G_OPT
988 bool "2G/2G user/kernel split (for full 2G low memory)"
990 bool "1G/3G user/kernel split"
995 default 0xB0000000 if VMSPLIT_3G_OPT
996 default 0x80000000 if VMSPLIT_2G
997 default 0x78000000 if VMSPLIT_2G_OPT
998 default 0x40000000 if VMSPLIT_1G
1004 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1007 bool "PAE (Physical Address Extension) Support"
1008 depends on X86_32 && !HIGHMEM4G
1010 PAE is required for NX support, and furthermore enables
1011 larger swapspace support for non-overcommit purposes. It
1012 has the cost of more pagetable lookup overhead, and also
1013 consumes more pagetable space per process.
1015 config ARCH_PHYS_ADDR_T_64BIT
1016 def_bool X86_64 || X86_PAE
1018 config DIRECT_GBPAGES
1019 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1023 Allow the kernel linear mapping to use 1GB pages on CPUs that
1024 support it. This can improve the kernel's performance a tiny bit by
1025 reducing TLB pressure. If in doubt, say "Y".
1027 # Common NUMA Features
1029 bool "Numa Memory Allocation and Scheduler Support"
1031 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1033 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1035 Enable NUMA (Non Uniform Memory Access) support.
1037 The kernel will try to allocate memory used by a CPU on the
1038 local memory controller of the CPU and add some more
1039 NUMA awareness to the kernel.
1041 For 64-bit this is recommended if the system is Intel Core i7
1042 (or later), AMD Opteron, or EM64T NUMA.
1044 For 32-bit this is only needed on (rare) 32-bit-only platforms
1045 that support NUMA topologies, such as NUMAQ / Summit, or if you
1046 boot a 32-bit kernel on a 64-bit NUMA platform.
1048 Otherwise, you should say N.
1050 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1051 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1055 prompt "Old style AMD Opteron NUMA detection"
1056 depends on X86_64 && NUMA && PCI
1058 Enable K8 NUMA node topology detection. You should say Y here if
1059 you have a multi processor AMD K8 system. This uses an old
1060 method to read the NUMA configuration directly from the builtin
1061 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1062 instead, which also takes priority if both are compiled in.
1064 config X86_64_ACPI_NUMA
1066 prompt "ACPI NUMA detection"
1067 depends on X86_64 && NUMA && ACPI && PCI
1070 Enable ACPI SRAT based node topology detection.
1072 # Some NUMA nodes have memory ranges that span
1073 # other nodes. Even though a pfn is valid and
1074 # between a node's start and end pfns, it may not
1075 # reside on that node. See memmap_init_zone()
1077 config NODES_SPAN_OTHER_NODES
1079 depends on X86_64_ACPI_NUMA
1082 bool "NUMA emulation"
1083 depends on X86_64 && NUMA
1085 Enable NUMA emulation. A flat machine will be split
1086 into virtual nodes when booted with "numa=fake=N", where N is the
1087 number of nodes. This is only useful for debugging.
1090 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1092 default "9" if MAXSMP
1093 default "6" if X86_64
1094 default "4" if X86_NUMAQ
1096 depends on NEED_MULTIPLE_NODES
1098 Specify the maximum number of NUMA Nodes available on the target
1099 system. Increases memory reserved to accomodate various tables.
1101 config HAVE_ARCH_BOOTMEM_NODE
1103 depends on X86_32 && NUMA
1105 config ARCH_HAVE_MEMORY_PRESENT
1107 depends on X86_32 && DISCONTIGMEM
1109 config NEED_NODE_MEMMAP_SIZE
1111 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1113 config HAVE_ARCH_ALLOC_REMAP
1115 depends on X86_32 && NUMA
1117 config ARCH_FLATMEM_ENABLE
1119 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1121 config ARCH_DISCONTIGMEM_ENABLE
1123 depends on NUMA && X86_32
1125 config ARCH_DISCONTIGMEM_DEFAULT
1127 depends on NUMA && X86_32
1129 config ARCH_SPARSEMEM_DEFAULT
1133 config ARCH_SPARSEMEM_ENABLE
1135 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1136 select SPARSEMEM_STATIC if X86_32
1137 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1139 config ARCH_SELECT_MEMORY_MODEL
1141 depends on ARCH_SPARSEMEM_ENABLE
1143 config ARCH_MEMORY_PROBE
1145 depends on MEMORY_HOTPLUG
1150 bool "Allocate 3rd-level pagetables from highmem"
1151 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1153 The VM uses one page table entry for each page of physical memory.
1154 For systems with a lot of RAM, this can be wasteful of precious
1155 low memory. Setting this option will put user-space page table
1156 entries in high memory.
1158 config X86_CHECK_BIOS_CORRUPTION
1159 bool "Check for low memory corruption"
1161 Periodically check for memory corruption in low memory, which
1162 is suspected to be caused by BIOS. Even when enabled in the
1163 configuration, it is disabled at runtime. Enable it by
1164 setting "memory_corruption_check=1" on the kernel command
1165 line. By default it scans the low 64k of memory every 60
1166 seconds; see the memory_corruption_check_size and
1167 memory_corruption_check_period parameters in
1168 Documentation/kernel-parameters.txt to adjust this.
1170 When enabled with the default parameters, this option has
1171 almost no overhead, as it reserves a relatively small amount
1172 of memory and scans it infrequently. It both detects corruption
1173 and prevents it from affecting the running system.
1175 It is, however, intended as a diagnostic tool; if repeatable
1176 BIOS-originated corruption always affects the same memory,
1177 you can use memmap= to prevent the kernel from using that
1180 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1181 bool "Set the default setting of memory_corruption_check"
1182 depends on X86_CHECK_BIOS_CORRUPTION
1185 Set whether the default state of memory_corruption_check is
1188 config X86_RESERVE_LOW_64K
1189 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1192 Reserve the first 64K of physical RAM on BIOSes that are known
1193 to potentially corrupt that memory range. A numbers of BIOSes are
1194 known to utilize this area during suspend/resume, so it must not
1195 be used by the kernel.
1197 Set this to N if you are absolutely sure that you trust the BIOS
1198 to get all its memory reservations and usages right.
1200 If you have doubts about the BIOS (e.g. suspend/resume does not
1201 work or there's kernel crashes after certain hardware hotplug
1202 events) and it's not AMI or Phoenix, then you might want to enable
1203 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1204 corruption patterns.
1208 config MATH_EMULATION
1210 prompt "Math emulation" if X86_32
1212 Linux can emulate a math coprocessor (used for floating point
1213 operations) if you don't have one. 486DX and Pentium processors have
1214 a math coprocessor built in, 486SX and 386 do not, unless you added
1215 a 487DX or 387, respectively. (The messages during boot time can
1216 give you some hints here ["man dmesg"].) Everyone needs either a
1217 coprocessor or this emulation.
1219 If you don't have a math coprocessor, you need to say Y here; if you
1220 say Y here even though you have a coprocessor, the coprocessor will
1221 be used nevertheless. (This behavior can be changed with the kernel
1222 command line option "no387", which comes handy if your coprocessor
1223 is broken. Try "man bootparam" or see the documentation of your boot
1224 loader (lilo or loadlin) about how to pass options to the kernel at
1225 boot time.) This means that it is a good idea to say Y here if you
1226 intend to use this kernel on different machines.
1228 More information about the internals of the Linux math coprocessor
1229 emulation can be found in <file:arch/x86/math-emu/README>.
1231 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1232 kernel, it won't hurt.
1235 bool "MTRR (Memory Type Range Register) support"
1237 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1238 the Memory Type Range Registers (MTRRs) may be used to control
1239 processor access to memory ranges. This is most useful if you have
1240 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1241 allows bus write transfers to be combined into a larger transfer
1242 before bursting over the PCI/AGP bus. This can increase performance
1243 of image write operations 2.5 times or more. Saying Y here creates a
1244 /proc/mtrr file which may be used to manipulate your processor's
1245 MTRRs. Typically the X server should use this.
1247 This code has a reasonably generic interface so that similar
1248 control registers on other processors can be easily supported
1251 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1252 Registers (ARRs) which provide a similar functionality to MTRRs. For
1253 these, the ARRs are used to emulate the MTRRs.
1254 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1255 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1256 write-combining. All of these processors are supported by this code
1257 and it makes sense to say Y here if you have one of them.
1259 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1260 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1261 can lead to all sorts of problems, so it's good to say Y here.
1263 You can safely say Y even if your machine doesn't have MTRRs, you'll
1264 just add about 9 KB to your kernel.
1266 See <file:Documentation/x86/mtrr.txt> for more information.
1268 config MTRR_SANITIZER
1270 prompt "MTRR cleanup support"
1273 Convert MTRR layout from continuous to discrete, so X drivers can
1274 add writeback entries.
1276 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1277 The largest mtrr entry size for a continous block can be set with
1282 config MTRR_SANITIZER_ENABLE_DEFAULT
1283 int "MTRR cleanup enable value (0-1)"
1286 depends on MTRR_SANITIZER
1288 Enable mtrr cleanup default value
1290 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1291 int "MTRR cleanup spare reg num (0-7)"
1294 depends on MTRR_SANITIZER
1296 mtrr cleanup spare entries default, it can be changed via
1297 mtrr_spare_reg_nr=N on the kernel command line.
1301 prompt "x86 PAT support"
1304 Use PAT attributes to setup page level cache control.
1306 PATs are the modern equivalents of MTRRs and are much more
1307 flexible than MTRRs.
1309 Say N here if you see bootup problems (boot crash, boot hang,
1310 spontaneous reboots) or a non-working video driver.
1315 bool "EFI runtime service support"
1318 This enables the kernel to use EFI runtime services that are
1319 available (such as the EFI variable services).
1321 This option is only useful on systems that have EFI firmware.
1322 In addition, you should use the latest ELILO loader available
1323 at <http://elilo.sourceforge.net> in order to take advantage
1324 of EFI runtime services. However, even with this option, the
1325 resultant kernel should continue to boot on existing non-EFI
1330 prompt "Enable seccomp to safely compute untrusted bytecode"
1332 This kernel feature is useful for number crunching applications
1333 that may need to compute untrusted bytecode during their
1334 execution. By using pipes or other transports made available to
1335 the process as file descriptors supporting the read/write
1336 syscalls, it's possible to isolate those applications in
1337 their own address space using seccomp. Once seccomp is
1338 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1339 and the task is only allowed to execute a few safe syscalls
1340 defined by each seccomp mode.
1342 If unsure, say Y. Only embedded should say N here.
1344 config CC_STACKPROTECTOR
1345 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1346 depends on X86_64 && EXPERIMENTAL && BROKEN
1348 This option turns on the -fstack-protector GCC feature. This
1349 feature puts, at the beginning of critical functions, a canary
1350 value on the stack just before the return address, and validates
1351 the value just before actually returning. Stack based buffer
1352 overflows (that need to overwrite this return address) now also
1353 overwrite the canary, which gets detected and the attack is then
1354 neutralized via a kernel panic.
1356 This feature requires gcc version 4.2 or above, or a distribution
1357 gcc with the feature backported. Older versions are automatically
1358 detected and for those versions, this configuration option is ignored.
1360 config CC_STACKPROTECTOR_ALL
1361 bool "Use stack-protector for all functions"
1362 depends on CC_STACKPROTECTOR
1364 Normally, GCC only inserts the canary value protection for
1365 functions that use large-ish on-stack buffers. By enabling
1366 this option, GCC will be asked to do this for ALL functions.
1368 source kernel/Kconfig.hz
1371 bool "kexec system call"
1372 depends on X86_BIOS_REBOOT
1374 kexec is a system call that implements the ability to shutdown your
1375 current kernel, and to start another kernel. It is like a reboot
1376 but it is independent of the system firmware. And like a reboot
1377 you can start any kernel with it, not just Linux.
1379 The name comes from the similarity to the exec system call.
1381 It is an ongoing process to be certain the hardware in a machine
1382 is properly shutdown, so do not be surprised if this code does not
1383 initially work for you. It may help to enable device hotplugging
1384 support. As of this writing the exact hardware interface is
1385 strongly in flux, so no good recommendation can be made.
1388 bool "kernel crash dumps"
1389 depends on X86_64 || (X86_32 && HIGHMEM)
1391 Generate crash dump after being started by kexec.
1392 This should be normally only set in special crash dump kernels
1393 which are loaded in the main kernel with kexec-tools into
1394 a specially reserved region and then later executed after
1395 a crash by kdump/kexec. The crash dump kernel must be compiled
1396 to a memory address not used by the main kernel or BIOS using
1397 PHYSICAL_START, or it must be built as a relocatable image
1398 (CONFIG_RELOCATABLE=y).
1399 For more details see Documentation/kdump/kdump.txt
1402 bool "kexec jump (EXPERIMENTAL)"
1403 depends on EXPERIMENTAL
1404 depends on KEXEC && HIBERNATION && X86_32
1406 Jump between original kernel and kexeced kernel and invoke
1407 code in physical address mode via KEXEC
1409 config PHYSICAL_START
1410 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1411 default "0x1000000" if X86_NUMAQ
1412 default "0x200000" if X86_64
1415 This gives the physical address where the kernel is loaded.
1417 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1418 bzImage will decompress itself to above physical address and
1419 run from there. Otherwise, bzImage will run from the address where
1420 it has been loaded by the boot loader and will ignore above physical
1423 In normal kdump cases one does not have to set/change this option
1424 as now bzImage can be compiled as a completely relocatable image
1425 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1426 address. This option is mainly useful for the folks who don't want
1427 to use a bzImage for capturing the crash dump and want to use a
1428 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1429 to be specifically compiled to run from a specific memory area
1430 (normally a reserved region) and this option comes handy.
1432 So if you are using bzImage for capturing the crash dump, leave
1433 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1434 Otherwise if you plan to use vmlinux for capturing the crash dump
1435 change this value to start of the reserved region (Typically 16MB
1436 0x1000000). In other words, it can be set based on the "X" value as
1437 specified in the "crashkernel=YM@XM" command line boot parameter
1438 passed to the panic-ed kernel. Typically this parameter is set as
1439 crashkernel=64M@16M. Please take a look at
1440 Documentation/kdump/kdump.txt for more details about crash dumps.
1442 Usage of bzImage for capturing the crash dump is recommended as
1443 one does not have to build two kernels. Same kernel can be used
1444 as production kernel and capture kernel. Above option should have
1445 gone away after relocatable bzImage support is introduced. But it
1446 is present because there are users out there who continue to use
1447 vmlinux for dump capture. This option should go away down the
1450 Don't change this unless you know what you are doing.
1453 bool "Build a relocatable kernel (EXPERIMENTAL)"
1454 depends on EXPERIMENTAL
1456 This builds a kernel image that retains relocation information
1457 so it can be loaded someplace besides the default 1MB.
1458 The relocations tend to make the kernel binary about 10% larger,
1459 but are discarded at runtime.
1461 One use is for the kexec on panic case where the recovery kernel
1462 must live at a different physical address than the primary
1465 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1466 it has been loaded at and the compile time physical address
1467 (CONFIG_PHYSICAL_START) is ignored.
1469 config PHYSICAL_ALIGN
1471 prompt "Alignment value to which kernel should be aligned" if X86_32
1472 default "0x100000" if X86_32
1473 default "0x200000" if X86_64
1474 range 0x2000 0x400000
1476 This value puts the alignment restrictions on physical address
1477 where kernel is loaded and run from. Kernel is compiled for an
1478 address which meets above alignment restriction.
1480 If bootloader loads the kernel at a non-aligned address and
1481 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1482 address aligned to above value and run from there.
1484 If bootloader loads the kernel at a non-aligned address and
1485 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1486 load address and decompress itself to the address it has been
1487 compiled for and run from there. The address for which kernel is
1488 compiled already meets above alignment restrictions. Hence the
1489 end result is that kernel runs from a physical address meeting
1490 above alignment restrictions.
1492 Don't change this unless you know what you are doing.
1495 bool "Support for hot-pluggable CPUs"
1496 depends on SMP && HOTPLUG && !X86_VOYAGER
1498 Say Y here to allow turning CPUs off and on. CPUs can be
1499 controlled through /sys/devices/system/cpu.
1500 ( Note: power management support will enable this option
1501 automatically on SMP systems. )
1502 Say N if you want to disable CPU hotplug.
1506 prompt "Compat VDSO support"
1507 depends on X86_32 || IA32_EMULATION
1509 Map the 32-bit VDSO to the predictable old-style address too.
1511 Say N here if you are running a sufficiently recent glibc
1512 version (2.3.3 or later), to remove the high-mapped
1513 VDSO mapping and to exclusively use the randomized VDSO.
1518 bool "Built-in kernel command line"
1521 Allow for specifying boot arguments to the kernel at
1522 build time. On some systems (e.g. embedded ones), it is
1523 necessary or convenient to provide some or all of the
1524 kernel boot arguments with the kernel itself (that is,
1525 to not rely on the boot loader to provide them.)
1527 To compile command line arguments into the kernel,
1528 set this option to 'Y', then fill in the
1529 the boot arguments in CONFIG_CMDLINE.
1531 Systems with fully functional boot loaders (i.e. non-embedded)
1532 should leave this option set to 'N'.
1535 string "Built-in kernel command string"
1536 depends on CMDLINE_BOOL
1539 Enter arguments here that should be compiled into the kernel
1540 image and used at boot time. If the boot loader provides a
1541 command line at boot time, it is appended to this string to
1542 form the full kernel command line, when the system boots.
1544 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1545 change this behavior.
1547 In most cases, the command line (whether built-in or provided
1548 by the boot loader) should specify the device for the root
1551 config CMDLINE_OVERRIDE
1552 bool "Built-in command line overrides boot loader arguments"
1554 depends on CMDLINE_BOOL
1556 Set this option to 'Y' to have the kernel ignore the boot loader
1557 command line, and use ONLY the built-in command line.
1559 This is used to work around broken boot loaders. This should
1560 be set to 'N' under normal conditions.
1564 config ARCH_ENABLE_MEMORY_HOTPLUG
1566 depends on X86_64 || (X86_32 && HIGHMEM)
1568 config ARCH_ENABLE_MEMORY_HOTREMOVE
1570 depends on MEMORY_HOTPLUG
1572 config HAVE_ARCH_EARLY_PFN_TO_NID
1576 menu "Power management and ACPI options"
1577 depends on !X86_VOYAGER
1579 config ARCH_HIBERNATION_HEADER
1581 depends on X86_64 && HIBERNATION
1583 source "kernel/power/Kconfig"
1585 source "drivers/acpi/Kconfig"
1590 depends on APM || APM_MODULE
1593 tristate "APM (Advanced Power Management) BIOS support"
1594 depends on X86_32 && PM_SLEEP
1596 APM is a BIOS specification for saving power using several different
1597 techniques. This is mostly useful for battery powered laptops with
1598 APM compliant BIOSes. If you say Y here, the system time will be
1599 reset after a RESUME operation, the /proc/apm device will provide
1600 battery status information, and user-space programs will receive
1601 notification of APM "events" (e.g. battery status change).
1603 If you select "Y" here, you can disable actual use of the APM
1604 BIOS by passing the "apm=off" option to the kernel at boot time.
1606 Note that the APM support is almost completely disabled for
1607 machines with more than one CPU.
1609 In order to use APM, you will need supporting software. For location
1610 and more information, read <file:Documentation/power/pm.txt> and the
1611 Battery Powered Linux mini-HOWTO, available from
1612 <http://www.tldp.org/docs.html#howto>.
1614 This driver does not spin down disk drives (see the hdparm(8)
1615 manpage ("man 8 hdparm") for that), and it doesn't turn off
1616 VESA-compliant "green" monitors.
1618 This driver does not support the TI 4000M TravelMate and the ACER
1619 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1620 desktop machines also don't have compliant BIOSes, and this driver
1621 may cause those machines to panic during the boot phase.
1623 Generally, if you don't have a battery in your machine, there isn't
1624 much point in using this driver and you should say N. If you get
1625 random kernel OOPSes or reboots that don't seem to be related to
1626 anything, try disabling/enabling this option (or disabling/enabling
1629 Some other things you should try when experiencing seemingly random,
1632 1) make sure that you have enough swap space and that it is
1634 2) pass the "no-hlt" option to the kernel
1635 3) switch on floating point emulation in the kernel and pass
1636 the "no387" option to the kernel
1637 4) pass the "floppy=nodma" option to the kernel
1638 5) pass the "mem=4M" option to the kernel (thereby disabling
1639 all but the first 4 MB of RAM)
1640 6) make sure that the CPU is not over clocked.
1641 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1642 8) disable the cache from your BIOS settings
1643 9) install a fan for the video card or exchange video RAM
1644 10) install a better fan for the CPU
1645 11) exchange RAM chips
1646 12) exchange the motherboard.
1648 To compile this driver as a module, choose M here: the
1649 module will be called apm.
1653 config APM_IGNORE_USER_SUSPEND
1654 bool "Ignore USER SUSPEND"
1656 This option will ignore USER SUSPEND requests. On machines with a
1657 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1658 series notebooks, it is necessary to say Y because of a BIOS bug.
1660 config APM_DO_ENABLE
1661 bool "Enable PM at boot time"
1663 Enable APM features at boot time. From page 36 of the APM BIOS
1664 specification: "When disabled, the APM BIOS does not automatically
1665 power manage devices, enter the Standby State, enter the Suspend
1666 State, or take power saving steps in response to CPU Idle calls."
1667 This driver will make CPU Idle calls when Linux is idle (unless this
1668 feature is turned off -- see "Do CPU IDLE calls", below). This
1669 should always save battery power, but more complicated APM features
1670 will be dependent on your BIOS implementation. You may need to turn
1671 this option off if your computer hangs at boot time when using APM
1672 support, or if it beeps continuously instead of suspending. Turn
1673 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1674 T400CDT. This is off by default since most machines do fine without
1678 bool "Make CPU Idle calls when idle"
1680 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1681 On some machines, this can activate improved power savings, such as
1682 a slowed CPU clock rate, when the machine is idle. These idle calls
1683 are made after the idle loop has run for some length of time (e.g.,
1684 333 mS). On some machines, this will cause a hang at boot time or
1685 whenever the CPU becomes idle. (On machines with more than one CPU,
1686 this option does nothing.)
1688 config APM_DISPLAY_BLANK
1689 bool "Enable console blanking using APM"
1691 Enable console blanking using the APM. Some laptops can use this to
1692 turn off the LCD backlight when the screen blanker of the Linux
1693 virtual console blanks the screen. Note that this is only used by
1694 the virtual console screen blanker, and won't turn off the backlight
1695 when using the X Window system. This also doesn't have anything to
1696 do with your VESA-compliant power-saving monitor. Further, this
1697 option doesn't work for all laptops -- it might not turn off your
1698 backlight at all, or it might print a lot of errors to the console,
1699 especially if you are using gpm.
1701 config APM_ALLOW_INTS
1702 bool "Allow interrupts during APM BIOS calls"
1704 Normally we disable external interrupts while we are making calls to
1705 the APM BIOS as a measure to lessen the effects of a badly behaving
1706 BIOS implementation. The BIOS should reenable interrupts if it
1707 needs to. Unfortunately, some BIOSes do not -- especially those in
1708 many of the newer IBM Thinkpads. If you experience hangs when you
1709 suspend, try setting this to Y. Otherwise, say N.
1713 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1715 source "drivers/cpuidle/Kconfig"
1717 source "drivers/idle/Kconfig"
1722 menu "Bus options (PCI etc.)"
1727 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1729 Find out whether you have a PCI motherboard. PCI is the name of a
1730 bus system, i.e. the way the CPU talks to the other stuff inside
1731 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1732 VESA. If you have PCI, say Y, otherwise N.
1735 prompt "PCI access mode"
1736 depends on X86_32 && PCI
1739 On PCI systems, the BIOS can be used to detect the PCI devices and
1740 determine their configuration. However, some old PCI motherboards
1741 have BIOS bugs and may crash if this is done. Also, some embedded
1742 PCI-based systems don't have any BIOS at all. Linux can also try to
1743 detect the PCI hardware directly without using the BIOS.
1745 With this option, you can specify how Linux should detect the
1746 PCI devices. If you choose "BIOS", the BIOS will be used,
1747 if you choose "Direct", the BIOS won't be used, and if you
1748 choose "MMConfig", then PCI Express MMCONFIG will be used.
1749 If you choose "Any", the kernel will try MMCONFIG, then the
1750 direct access method and falls back to the BIOS if that doesn't
1751 work. If unsure, go with the default, which is "Any".
1756 config PCI_GOMMCONFIG
1773 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1775 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1778 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1782 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1786 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1793 bool "Support mmconfig PCI config space access"
1794 depends on X86_64 && PCI && ACPI
1797 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1798 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1800 DMA remapping (DMAR) devices support enables independent address
1801 translations for Direct Memory Access (DMA) from devices.
1802 These DMA remapping devices are reported via ACPI tables
1803 and include PCI device scope covered by these DMA
1806 config DMAR_DEFAULT_ON
1808 prompt "Enable DMA Remapping Devices by default"
1811 Selecting this option will enable a DMAR device at boot time if
1812 one is found. If this option is not selected, DMAR support can
1813 be enabled by passing intel_iommu=on to the kernel. It is
1814 recommended you say N here while the DMAR code remains
1819 prompt "Support for Graphics workaround"
1822 Current Graphics drivers tend to use physical address
1823 for DMA and avoid using DMA APIs. Setting this config
1824 option permits the IOMMU driver to set a unity map for
1825 all the OS-visible memory. Hence the driver can continue
1826 to use physical addresses for DMA.
1828 config DMAR_FLOPPY_WA
1832 Floppy disk drivers are know to bypass DMA API calls
1833 thereby failing to work when IOMMU is enabled. This
1834 workaround will setup a 1:1 mapping for the first
1835 16M to make floppy (an ISA device) work.
1838 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1839 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1841 Supports Interrupt remapping for IO-APIC and MSI devices.
1842 To use x2apic mode in the CPU's which support x2APIC enhancements or
1843 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1845 source "drivers/pci/pcie/Kconfig"
1847 source "drivers/pci/Kconfig"
1849 # x86_64 have no ISA slots, but do have ISA-style DMA.
1857 depends on !X86_VOYAGER
1859 Find out whether you have ISA slots on your motherboard. ISA is the
1860 name of a bus system, i.e. the way the CPU talks to the other stuff
1861 inside your box. Other bus systems are PCI, EISA, MicroChannel
1862 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1863 newer boards don't support it. If you have ISA, say Y, otherwise N.
1869 The Extended Industry Standard Architecture (EISA) bus was
1870 developed as an open alternative to the IBM MicroChannel bus.
1872 The EISA bus provided some of the features of the IBM MicroChannel
1873 bus while maintaining backward compatibility with cards made for
1874 the older ISA bus. The EISA bus saw limited use between 1988 and
1875 1995 when it was made obsolete by the PCI bus.
1877 Say Y here if you are building a kernel for an EISA-based machine.
1881 source "drivers/eisa/Kconfig"
1884 bool "MCA support" if !X86_VOYAGER
1885 default y if X86_VOYAGER
1887 MicroChannel Architecture is found in some IBM PS/2 machines and
1888 laptops. It is a bus system similar to PCI or ISA. See
1889 <file:Documentation/mca.txt> (and especially the web page given
1890 there) before attempting to build an MCA bus kernel.
1892 source "drivers/mca/Kconfig"
1895 tristate "NatSemi SCx200 support"
1896 depends on !X86_VOYAGER
1898 This provides basic support for National Semiconductor's
1899 (now AMD's) Geode processors. The driver probes for the
1900 PCI-IDs of several on-chip devices, so its a good dependency
1901 for other scx200_* drivers.
1903 If compiled as a module, the driver is named scx200.
1905 config SCx200HR_TIMER
1906 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1907 depends on SCx200 && GENERIC_TIME
1910 This driver provides a clocksource built upon the on-chip
1911 27MHz high-resolution timer. Its also a workaround for
1912 NSC Geode SC-1100's buggy TSC, which loses time when the
1913 processor goes idle (as is done by the scheduler). The
1914 other workaround is idle=poll boot option.
1916 config GEODE_MFGPT_TIMER
1918 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1919 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1921 This driver provides a clock event source based on the MFGPT
1922 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1923 MFGPTs have a better resolution and max interval than the
1924 generic PIT, and are suitable for use as high-res timers.
1927 bool "One Laptop Per Child support"
1930 Add support for detecting the unique features of the OLPC
1937 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1939 source "drivers/pcmcia/Kconfig"
1941 source "drivers/pci/hotplug/Kconfig"
1946 menu "Executable file formats / Emulations"
1948 source "fs/Kconfig.binfmt"
1950 config IA32_EMULATION
1951 bool "IA32 Emulation"
1953 select COMPAT_BINFMT_ELF
1955 Include code to run 32-bit programs under a 64-bit kernel. You should
1956 likely turn this on, unless you're 100% sure that you don't have any
1957 32-bit programs left.
1960 tristate "IA32 a.out support"
1961 depends on IA32_EMULATION
1963 Support old a.out binaries in the 32bit emulation.
1967 depends on IA32_EMULATION
1969 config COMPAT_FOR_U64_ALIGNMENT
1973 config SYSVIPC_COMPAT
1975 depends on COMPAT && SYSVIPC
1980 config HAVE_ATOMIC_IOMAP
1984 source "net/Kconfig"
1986 source "drivers/Kconfig"
1988 source "drivers/firmware/Kconfig"
1992 source "arch/x86/Kconfig.debug"
1994 source "security/Kconfig"
1996 source "crypto/Kconfig"
1998 source "arch/x86/kvm/Kconfig"
2000 source "lib/Kconfig"
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