2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
43 select HAVE_KERNEL_GZIP
44 select HAVE_KERNEL_BZIP2
45 select HAVE_KERNEL_LZMA
49 default "arch/x86/configs/i386_defconfig" if X86_32
50 default "arch/x86/configs/x86_64_defconfig" if X86_64
55 config GENERIC_CMOS_UPDATE
58 config CLOCKSOURCE_WATCHDOG
61 config GENERIC_CLOCKEVENTS
64 config GENERIC_CLOCKEVENTS_BROADCAST
66 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
68 config LOCKDEP_SUPPORT
71 config STACKTRACE_SUPPORT
74 config HAVE_LATENCYTOP_SUPPORT
77 config FAST_CMPXCHG_LOCAL
90 config GENERIC_ISA_DMA
99 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
101 config GENERIC_BUG_RELATIVE_POINTERS
104 config GENERIC_HWEIGHT
110 config ARCH_MAY_HAVE_PC_FDC
113 config RWSEM_GENERIC_SPINLOCK
116 config RWSEM_XCHGADD_ALGORITHM
119 config ARCH_HAS_CPU_IDLE_WAIT
122 config GENERIC_CALIBRATE_DELAY
125 config GENERIC_TIME_VSYSCALL
129 config ARCH_HAS_CPU_RELAX
132 config ARCH_HAS_DEFAULT_IDLE
135 config ARCH_HAS_CACHE_LINE_SIZE
138 config HAVE_SETUP_PER_CPU_AREA
141 config HAVE_DYNAMIC_PER_CPU_AREA
144 config HAVE_CPUMASK_OF_CPU_MAP
147 config ARCH_HIBERNATION_POSSIBLE
150 config ARCH_SUSPEND_POSSIBLE
157 config ARCH_POPULATES_NODE_MAP
164 config ARCH_SUPPORTS_OPTIMIZED_INLINING
167 # Use the generic interrupt handling code in kernel/irq/:
168 config GENERIC_HARDIRQS
172 config GENERIC_HARDIRQS_NO__DO_IRQ
175 config GENERIC_IRQ_PROBE
179 config GENERIC_PENDING_IRQ
181 depends on GENERIC_HARDIRQS && SMP
184 config USE_GENERIC_SMP_HELPERS
190 depends on X86_32 && SMP
194 depends on X86_64 && SMP
201 config X86_TRAMPOLINE
203 depends on SMP || (64BIT && ACPI_SLEEP)
206 config X86_32_LAZY_GS
208 depends on X86_32 && !CC_STACKPROTECTOR
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.
248 bool "Support x2apic"
249 depends on X86_LOCAL_APIC && X86_64
251 This enables x2apic support on CPUs that have this feature.
253 This allows 32-bit apic IDs (so it can support very large systems),
254 and accesses the local apic via MSRs not via mmio.
256 ( On certain CPU models you may need to enable INTR_REMAP too,
257 to get functional x2apic mode. )
259 If you don't know what to do here, say N.
262 bool "Support sparse irq numbering"
263 depends on PCI_MSI || HT_IRQ
265 This enables support for sparse irqs. This is useful for distro
266 kernels that want to define a high CONFIG_NR_CPUS value but still
267 want to have low kernel memory footprint on smaller machines.
269 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
270 out the irq_desc[] array in a more NUMA-friendly way. )
272 If you don't know what to do here, say N.
274 config NUMA_MIGRATE_IRQ_DESC
275 bool "Move irq desc when changing irq smp_affinity"
276 depends on SPARSE_IRQ && NUMA
279 This enables moving irq_desc to cpu/node that irq will use handled.
281 If you don't know what to do here, say N.
284 bool "Enable MPS table" if ACPI
286 depends on X86_LOCAL_APIC
288 For old smp systems that do not have proper acpi support. Newer systems
289 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
292 bool "Support for big SMP systems with more than 8 CPUs"
293 depends on X86_32 && SMP
295 This option is needed for the systems that have more than 8 CPUs
298 config X86_EXTENDED_PLATFORM
299 bool "Support for extended (non-PC) x86 platforms"
302 If you disable this option then the kernel will only support
303 standard PC platforms. (which covers the vast majority of
306 If you enable this option then you'll be able to select support
307 for the following (non-PC) 32 bit x86 platforms:
311 SGI 320/540 (Visual Workstation)
312 Summit/EXA (IBM x440)
313 Unisys ES7000 IA32 series
315 If you have one of these systems, or if you want to build a
316 generic distribution kernel, say Y here - otherwise say N.
320 config X86_EXTENDED_PLATFORM
321 bool "Support for extended (non-PC) x86 platforms"
324 If you disable this option then the kernel will only support
325 standard PC platforms. (which covers the vast majority of
328 If you enable this option then you'll be able to select support
329 for the following (non-PC) 64 bit x86 platforms:
333 If you have one of these systems, or if you want to build a
334 generic distribution kernel, say Y here - otherwise say N.
336 # This is an alphabetically sorted list of 64 bit extended platforms
337 # Please maintain the alphabetic order if and when there are additions
342 depends on X86_64 && PCI
343 depends on X86_EXTENDED_PLATFORM
345 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
346 supposed to run on these EM64T-based machines. Only choose this option
347 if you have one of these machines.
350 bool "SGI Ultraviolet"
352 depends on X86_EXTENDED_PLATFORM
355 This option is needed in order to support SGI Ultraviolet systems.
356 If you don't have one of these, you should say N here.
358 # Following is an alphabetically sorted list of 32 bit extended platforms
359 # Please maintain the alphabetic order if and when there are additions
364 depends on X86_EXTENDED_PLATFORM
366 Select this for an AMD Elan processor.
368 Do not use this option for K6/Athlon/Opteron processors!
370 If unsure, choose "PC-compatible" instead.
373 bool "RDC R-321x SoC"
375 depends on X86_EXTENDED_PLATFORM
377 select X86_REBOOTFIXUPS
379 This option is needed for RDC R-321x system-on-chip, also known
381 If you don't have one of these chips, you should say N here.
383 config X86_32_NON_STANDARD
384 bool "Support non-standard 32-bit SMP architectures"
385 depends on X86_32 && SMP
386 depends on X86_EXTENDED_PLATFORM
388 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
389 subarchitectures. It is intended for a generic binary kernel.
390 if you select them all, kernel will probe it one by one. and will
393 # Alphabetically sorted list of Non standard 32 bit platforms
396 bool "NUMAQ (IBM/Sequent)"
397 depends on X86_32_NON_STANDARD
401 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
402 NUMA multiquad box. This changes the way that processors are
403 bootstrapped, and uses Clustered Logical APIC addressing mode instead
404 of Flat Logical. You will need a new lynxer.elf file to flash your
405 firmware with - send email to <Martin.Bligh@us.ibm.com>.
408 bool "SGI 320/540 (Visual Workstation)"
409 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
410 depends on X86_32_NON_STANDARD
412 The SGI Visual Workstation series is an IA32-based workstation
413 based on SGI systems chips with some legacy PC hardware attached.
415 Say Y here to create a kernel to run on the SGI 320 or 540.
417 A kernel compiled for the Visual Workstation will run on general
418 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
421 bool "Summit/EXA (IBM x440)"
422 depends on X86_32_NON_STANDARD
424 This option is needed for IBM systems that use the Summit/EXA chipset.
425 In particular, it is needed for the x440.
428 bool "Unisys ES7000 IA32 series"
429 depends on X86_32_NON_STANDARD && X86_BIGSMP
431 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
432 supposed to run on an IA32-based Unisys ES7000 system.
434 config SCHED_OMIT_FRAME_POINTER
436 prompt "Single-depth WCHAN output"
439 Calculate simpler /proc/<PID>/wchan values. If this option
440 is disabled then wchan values will recurse back to the
441 caller function. This provides more accurate wchan values,
442 at the expense of slightly more scheduling overhead.
444 If in doubt, say "Y".
446 menuconfig PARAVIRT_GUEST
447 bool "Paravirtualized guest support"
449 Say Y here to get to see options related to running Linux under
450 various hypervisors. This option alone does not add any kernel code.
452 If you say N, all options in this submenu will be skipped and disabled.
456 source "arch/x86/xen/Kconfig"
459 bool "VMI Guest support"
463 VMI provides a paravirtualized interface to the VMware ESX server
464 (it could be used by other hypervisors in theory too, but is not
465 at the moment), by linking the kernel to a GPL-ed ROM module
466 provided by the hypervisor.
469 bool "KVM paravirtualized clock"
471 select PARAVIRT_CLOCK
473 Turning on this option will allow you to run a paravirtualized clock
474 when running over the KVM hypervisor. Instead of relying on a PIT
475 (or probably other) emulation by the underlying device model, the host
476 provides the guest with timing infrastructure such as time of day, and
480 bool "KVM Guest support"
483 This option enables various optimizations for running under the KVM
486 source "arch/x86/lguest/Kconfig"
489 bool "Enable paravirtualization code"
491 This changes the kernel so it can modify itself when it is run
492 under a hypervisor, potentially improving performance significantly
493 over full virtualization. However, when run without a hypervisor
494 the kernel is theoretically slower and slightly larger.
496 config PARAVIRT_CLOCK
502 config PARAVIRT_DEBUG
503 bool "paravirt-ops debugging"
504 depends on PARAVIRT && DEBUG_KERNEL
506 Enable to debug paravirt_ops internals. Specifically, BUG if
507 a paravirt_op is missing when it is called.
512 This option adds a kernel parameter 'memtest', which allows memtest
514 memtest=0, mean disabled; -- default
515 memtest=1, mean do 1 test pattern;
517 memtest=4, mean do 4 test patterns.
518 If you are unsure how to answer this question, answer N.
520 config X86_SUMMIT_NUMA
522 depends on X86_32 && NUMA && X86_32_NON_STANDARD
524 config X86_CYCLONE_TIMER
526 depends on X86_32_NON_STANDARD
528 source "arch/x86/Kconfig.cpu"
532 prompt "HPET Timer Support" if X86_32
534 Use the IA-PC HPET (High Precision Event Timer) to manage
535 time in preference to the PIT and RTC, if a HPET is
537 HPET is the next generation timer replacing legacy 8254s.
538 The HPET provides a stable time base on SMP
539 systems, unlike the TSC, but it is more expensive to access,
540 as it is off-chip. You can find the HPET spec at
541 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
543 You can safely choose Y here. However, HPET will only be
544 activated if the platform and the BIOS support this feature.
545 Otherwise the 8254 will be used for timing services.
547 Choose N to continue using the legacy 8254 timer.
549 config HPET_EMULATE_RTC
551 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
553 # Mark as embedded because too many people got it wrong.
554 # The code disables itself when not needed.
557 bool "Enable DMI scanning" if EMBEDDED
559 Enabled scanning of DMI to identify machine quirks. Say Y
560 here unless you have verified that your setup is not
561 affected by entries in the DMI blacklist. Required by PNP
565 bool "GART IOMMU support" if EMBEDDED
569 depends on X86_64 && PCI
571 Support for full DMA access of devices with 32bit memory access only
572 on systems with more than 3GB. This is usually needed for USB,
573 sound, many IDE/SATA chipsets and some other devices.
574 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
575 based hardware IOMMU and a software bounce buffer based IOMMU used
576 on Intel systems and as fallback.
577 The code is only active when needed (enough memory and limited
578 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
582 bool "IBM Calgary IOMMU support"
584 depends on X86_64 && PCI && EXPERIMENTAL
586 Support for hardware IOMMUs in IBM's xSeries x366 and x460
587 systems. Needed to run systems with more than 3GB of memory
588 properly with 32-bit PCI devices that do not support DAC
589 (Double Address Cycle). Calgary also supports bus level
590 isolation, where all DMAs pass through the IOMMU. This
591 prevents them from going anywhere except their intended
592 destination. This catches hard-to-find kernel bugs and
593 mis-behaving drivers and devices that do not use the DMA-API
594 properly to set up their DMA buffers. The IOMMU can be
595 turned off at boot time with the iommu=off parameter.
596 Normally the kernel will make the right choice by itself.
599 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
601 prompt "Should Calgary be enabled by default?"
602 depends on CALGARY_IOMMU
604 Should Calgary be enabled by default? if you choose 'y', Calgary
605 will be used (if it exists). If you choose 'n', Calgary will not be
606 used even if it exists. If you choose 'n' and would like to use
607 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
611 bool "AMD IOMMU support"
614 depends on X86_64 && PCI && ACPI
616 With this option you can enable support for AMD IOMMU hardware in
617 your system. An IOMMU is a hardware component which provides
618 remapping of DMA memory accesses from devices. With an AMD IOMMU you
619 can isolate the the DMA memory of different devices and protect the
620 system from misbehaving device drivers or hardware.
622 You can find out if your system has an AMD IOMMU if you look into
623 your BIOS for an option to enable it or if you have an IVRS ACPI
626 config AMD_IOMMU_STATS
627 bool "Export AMD IOMMU statistics to debugfs"
631 This option enables code in the AMD IOMMU driver to collect various
632 statistics about whats happening in the driver and exports that
633 information to userspace via debugfs.
636 # need this always selected by IOMMU for the VIA workaround
640 Support for software bounce buffers used on x86-64 systems
641 which don't have a hardware IOMMU (e.g. the current generation
642 of Intel's x86-64 CPUs). Using this PCI devices which can only
643 access 32-bits of memory can be used on systems with more than
644 3 GB of memory. If unsure, say Y.
647 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
650 def_bool (AMD_IOMMU || DMAR)
653 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
654 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
655 select CPUMASK_OFFSTACK
658 Configure maximum number of CPUS and NUMA Nodes for this architecture.
662 int "Maximum number of CPUs" if SMP && !MAXSMP
663 range 2 512 if SMP && !MAXSMP
665 default "4096" if MAXSMP
666 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
669 This allows you to specify the maximum number of CPUs which this
670 kernel will support. The maximum supported value is 512 and the
671 minimum value which makes sense is 2.
673 This is purely to save memory - each supported CPU adds
674 approximately eight kilobytes to the kernel image.
677 bool "SMT (Hyperthreading) scheduler support"
680 SMT scheduler support improves the CPU scheduler's decision making
681 when dealing with Intel Pentium 4 chips with HyperThreading at a
682 cost of slightly increased overhead in some places. If unsure say
687 prompt "Multi-core scheduler support"
690 Multi-core scheduler support improves the CPU scheduler's decision
691 making when dealing with multi-core CPU chips at a cost of slightly
692 increased overhead in some places. If unsure say N here.
694 source "kernel/Kconfig.preempt"
697 bool "Local APIC support on uniprocessors"
698 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
700 A local APIC (Advanced Programmable Interrupt Controller) is an
701 integrated interrupt controller in the CPU. If you have a single-CPU
702 system which has a processor with a local APIC, you can say Y here to
703 enable and use it. If you say Y here even though your machine doesn't
704 have a local APIC, then the kernel will still run with no slowdown at
705 all. The local APIC supports CPU-generated self-interrupts (timer,
706 performance counters), and the NMI watchdog which detects hard
710 bool "IO-APIC support on uniprocessors"
711 depends on X86_UP_APIC
713 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
714 SMP-capable replacement for PC-style interrupt controllers. Most
715 SMP systems and many recent uniprocessor systems have one.
717 If you have a single-CPU system with an IO-APIC, you can say Y here
718 to use it. If you say Y here even though your machine doesn't have
719 an IO-APIC, then the kernel will still run with no slowdown at all.
721 config X86_LOCAL_APIC
723 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
727 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
729 config X86_VISWS_APIC
731 depends on X86_32 && X86_VISWS
733 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
734 bool "Reroute for broken boot IRQs"
736 depends on X86_IO_APIC
738 This option enables a workaround that fixes a source of
739 spurious interrupts. This is recommended when threaded
740 interrupt handling is used on systems where the generation of
741 superfluous "boot interrupts" cannot be disabled.
743 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
744 entry in the chipset's IO-APIC is masked (as, e.g. the RT
745 kernel does during interrupt handling). On chipsets where this
746 boot IRQ generation cannot be disabled, this workaround keeps
747 the original IRQ line masked so that only the equivalent "boot
748 IRQ" is delivered to the CPUs. The workaround also tells the
749 kernel to set up the IRQ handler on the boot IRQ line. In this
750 way only one interrupt is delivered to the kernel. Otherwise
751 the spurious second interrupt may cause the kernel to bring
752 down (vital) interrupt lines.
754 Only affects "broken" chipsets. Interrupt sharing may be
755 increased on these systems.
758 bool "Machine Check Exception"
760 Machine Check Exception support allows the processor to notify the
761 kernel if it detects a problem (e.g. overheating, component failure).
762 The action the kernel takes depends on the severity of the problem,
763 ranging from a warning message on the console, to halting the machine.
764 Your processor must be a Pentium or newer to support this - check the
765 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
766 have a design flaw which leads to false MCE events - hence MCE is
767 disabled on all P5 processors, unless explicitly enabled with "mce"
768 as a boot argument. Similarly, if MCE is built in and creates a
769 problem on some new non-standard machine, you can boot with "nomce"
770 to disable it. MCE support simply ignores non-MCE processors like
771 the 386 and 486, so nearly everyone can say Y here.
775 prompt "Intel MCE features"
776 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
778 Additional support for intel specific MCE features such as
783 prompt "AMD MCE features"
784 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
786 Additional support for AMD specific MCE features such as
787 the DRAM Error Threshold.
789 config X86_MCE_NONFATAL
790 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
791 depends on X86_32 && X86_MCE
793 Enabling this feature starts a timer that triggers every 5 seconds which
794 will look at the machine check registers to see if anything happened.
795 Non-fatal problems automatically get corrected (but still logged).
796 Disable this if you don't want to see these messages.
797 Seeing the messages this option prints out may be indicative of dying
798 or out-of-spec (ie, overclocked) hardware.
799 This option only does something on certain CPUs.
800 (AMD Athlon/Duron and Intel Pentium 4)
802 config X86_MCE_P4THERMAL
803 bool "check for P4 thermal throttling interrupt."
804 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
806 Enabling this feature will cause a message to be printed when the P4
807 enters thermal throttling.
810 bool "Enable VM86 support" if EMBEDDED
814 This option is required by programs like DOSEMU to run 16-bit legacy
815 code on X86 processors. It also may be needed by software like
816 XFree86 to initialize some video cards via BIOS. Disabling this
817 option saves about 6k.
820 tristate "Toshiba Laptop support"
823 This adds a driver to safely access the System Management Mode of
824 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
825 not work on models with a Phoenix BIOS. The System Management Mode
826 is used to set the BIOS and power saving options on Toshiba portables.
828 For information on utilities to make use of this driver see the
829 Toshiba Linux utilities web site at:
830 <http://www.buzzard.org.uk/toshiba/>.
832 Say Y if you intend to run this kernel on a Toshiba portable.
836 tristate "Dell laptop support"
838 This adds a driver to safely access the System Management Mode
839 of the CPU on the Dell Inspiron 8000. The System Management Mode
840 is used to read cpu temperature and cooling fan status and to
841 control the fans on the I8K portables.
843 This driver has been tested only on the Inspiron 8000 but it may
844 also work with other Dell laptops. You can force loading on other
845 models by passing the parameter `force=1' to the module. Use at
848 For information on utilities to make use of this driver see the
849 I8K Linux utilities web site at:
850 <http://people.debian.org/~dz/i8k/>
852 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
855 config X86_REBOOTFIXUPS
856 bool "Enable X86 board specific fixups for reboot"
859 This enables chipset and/or board specific fixups to be done
860 in order to get reboot to work correctly. This is only needed on
861 some combinations of hardware and BIOS. The symptom, for which
862 this config is intended, is when reboot ends with a stalled/hung
865 Currently, the only fixup is for the Geode machines using
866 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
868 Say Y if you want to enable the fixup. Currently, it's safe to
869 enable this option even if you don't need it.
873 tristate "/dev/cpu/microcode - microcode support"
876 If you say Y here, you will be able to update the microcode on
877 certain Intel and AMD processors. The Intel support is for the
878 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
879 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
880 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
881 You will obviously need the actual microcode binary data itself
882 which is not shipped with the Linux kernel.
884 This option selects the general module only, you need to select
885 at least one vendor specific module as well.
887 To compile this driver as a module, choose M here: the
888 module will be called microcode.
890 config MICROCODE_INTEL
891 bool "Intel microcode patch loading support"
896 This options enables microcode patch loading support for Intel
899 For latest news and information on obtaining all the required
900 Intel ingredients for this driver, check:
901 <http://www.urbanmyth.org/microcode/>.
904 bool "AMD microcode patch loading support"
908 If you select this option, microcode patch loading support for AMD
909 processors will be enabled.
911 config MICROCODE_OLD_INTERFACE
916 tristate "/dev/cpu/*/msr - Model-specific register support"
918 This device gives privileged processes access to the x86
919 Model-Specific Registers (MSRs). It is a character device with
920 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
921 MSR accesses are directed to a specific CPU on multi-processor
925 tristate "/dev/cpu/*/cpuid - CPU information support"
927 This device gives processes access to the x86 CPUID instruction to
928 be executed on a specific processor. It is a character device
929 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
933 prompt "High Memory Support"
934 default HIGHMEM4G if !X86_NUMAQ
935 default HIGHMEM64G if X86_NUMAQ
940 depends on !X86_NUMAQ
942 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
943 However, the address space of 32-bit x86 processors is only 4
944 Gigabytes large. That means that, if you have a large amount of
945 physical memory, not all of it can be "permanently mapped" by the
946 kernel. The physical memory that's not permanently mapped is called
949 If you are compiling a kernel which will never run on a machine with
950 more than 1 Gigabyte total physical RAM, answer "off" here (default
951 choice and suitable for most users). This will result in a "3GB/1GB"
952 split: 3GB are mapped so that each process sees a 3GB virtual memory
953 space and the remaining part of the 4GB virtual memory space is used
954 by the kernel to permanently map as much physical memory as
957 If the machine has between 1 and 4 Gigabytes physical RAM, then
960 If more than 4 Gigabytes is used then answer "64GB" here. This
961 selection turns Intel PAE (Physical Address Extension) mode on.
962 PAE implements 3-level paging on IA32 processors. PAE is fully
963 supported by Linux, PAE mode is implemented on all recent Intel
964 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
965 then the kernel will not boot on CPUs that don't support PAE!
967 The actual amount of total physical memory will either be
968 auto detected or can be forced by using a kernel command line option
969 such as "mem=256M". (Try "man bootparam" or see the documentation of
970 your boot loader (lilo or loadlin) about how to pass options to the
971 kernel at boot time.)
973 If unsure, say "off".
977 depends on !X86_NUMAQ
979 Select this if you have a 32-bit processor and between 1 and 4
980 gigabytes of physical RAM.
984 depends on !M386 && !M486
987 Select this if you have a 32-bit processor and more than 4
988 gigabytes of physical RAM.
993 depends on EXPERIMENTAL
994 prompt "Memory split" if EMBEDDED
998 Select the desired split between kernel and user memory.
1000 If the address range available to the kernel is less than the
1001 physical memory installed, the remaining memory will be available
1002 as "high memory". Accessing high memory is a little more costly
1003 than low memory, as it needs to be mapped into the kernel first.
1004 Note that increasing the kernel address space limits the range
1005 available to user programs, making the address space there
1006 tighter. Selecting anything other than the default 3G/1G split
1007 will also likely make your kernel incompatible with binary-only
1010 If you are not absolutely sure what you are doing, leave this
1014 bool "3G/1G user/kernel split"
1015 config VMSPLIT_3G_OPT
1017 bool "3G/1G user/kernel split (for full 1G low memory)"
1019 bool "2G/2G user/kernel split"
1020 config VMSPLIT_2G_OPT
1022 bool "2G/2G user/kernel split (for full 2G low memory)"
1024 bool "1G/3G user/kernel split"
1029 default 0xB0000000 if VMSPLIT_3G_OPT
1030 default 0x80000000 if VMSPLIT_2G
1031 default 0x78000000 if VMSPLIT_2G_OPT
1032 default 0x40000000 if VMSPLIT_1G
1038 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1041 bool "PAE (Physical Address Extension) Support"
1042 depends on X86_32 && !HIGHMEM4G
1044 PAE is required for NX support, and furthermore enables
1045 larger swapspace support for non-overcommit purposes. It
1046 has the cost of more pagetable lookup overhead, and also
1047 consumes more pagetable space per process.
1049 config ARCH_PHYS_ADDR_T_64BIT
1050 def_bool X86_64 || X86_PAE
1052 config DIRECT_GBPAGES
1053 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1057 Allow the kernel linear mapping to use 1GB pages on CPUs that
1058 support it. This can improve the kernel's performance a tiny bit by
1059 reducing TLB pressure. If in doubt, say "Y".
1061 # Common NUMA Features
1063 bool "Numa Memory Allocation and Scheduler Support"
1065 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1066 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1068 Enable NUMA (Non Uniform Memory Access) support.
1070 The kernel will try to allocate memory used by a CPU on the
1071 local memory controller of the CPU and add some more
1072 NUMA awareness to the kernel.
1074 For 64-bit this is recommended if the system is Intel Core i7
1075 (or later), AMD Opteron, or EM64T NUMA.
1077 For 32-bit this is only needed on (rare) 32-bit-only platforms
1078 that support NUMA topologies, such as NUMAQ / Summit, or if you
1079 boot a 32-bit kernel on a 64-bit NUMA platform.
1081 Otherwise, you should say N.
1083 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1084 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1088 prompt "Old style AMD Opteron NUMA detection"
1089 depends on X86_64 && NUMA && PCI
1091 Enable K8 NUMA node topology detection. You should say Y here if
1092 you have a multi processor AMD K8 system. This uses an old
1093 method to read the NUMA configuration directly from the builtin
1094 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1095 instead, which also takes priority if both are compiled in.
1097 config X86_64_ACPI_NUMA
1099 prompt "ACPI NUMA detection"
1100 depends on X86_64 && NUMA && ACPI && PCI
1103 Enable ACPI SRAT based node topology detection.
1105 # Some NUMA nodes have memory ranges that span
1106 # other nodes. Even though a pfn is valid and
1107 # between a node's start and end pfns, it may not
1108 # reside on that node. See memmap_init_zone()
1110 config NODES_SPAN_OTHER_NODES
1112 depends on X86_64_ACPI_NUMA
1115 bool "NUMA emulation"
1116 depends on X86_64 && NUMA
1118 Enable NUMA emulation. A flat machine will be split
1119 into virtual nodes when booted with "numa=fake=N", where N is the
1120 number of nodes. This is only useful for debugging.
1123 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1125 default "9" if MAXSMP
1126 default "6" if X86_64
1127 default "4" if X86_NUMAQ
1129 depends on NEED_MULTIPLE_NODES
1131 Specify the maximum number of NUMA Nodes available on the target
1132 system. Increases memory reserved to accomodate various tables.
1134 config HAVE_ARCH_BOOTMEM
1136 depends on X86_32 && NUMA
1138 config ARCH_HAVE_MEMORY_PRESENT
1140 depends on X86_32 && DISCONTIGMEM
1142 config NEED_NODE_MEMMAP_SIZE
1144 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1146 config HAVE_ARCH_ALLOC_REMAP
1148 depends on X86_32 && NUMA
1150 config ARCH_FLATMEM_ENABLE
1152 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1154 config ARCH_DISCONTIGMEM_ENABLE
1156 depends on NUMA && X86_32
1158 config ARCH_DISCONTIGMEM_DEFAULT
1160 depends on NUMA && X86_32
1162 config ARCH_SPARSEMEM_DEFAULT
1166 config ARCH_SPARSEMEM_ENABLE
1168 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1169 select SPARSEMEM_STATIC if X86_32
1170 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1172 config ARCH_SELECT_MEMORY_MODEL
1174 depends on ARCH_SPARSEMEM_ENABLE
1176 config ARCH_MEMORY_PROBE
1178 depends on MEMORY_HOTPLUG
1183 bool "Allocate 3rd-level pagetables from highmem"
1184 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1186 The VM uses one page table entry for each page of physical memory.
1187 For systems with a lot of RAM, this can be wasteful of precious
1188 low memory. Setting this option will put user-space page table
1189 entries in high memory.
1191 config X86_CHECK_BIOS_CORRUPTION
1192 bool "Check for low memory corruption"
1194 Periodically check for memory corruption in low memory, which
1195 is suspected to be caused by BIOS. Even when enabled in the
1196 configuration, it is disabled at runtime. Enable it by
1197 setting "memory_corruption_check=1" on the kernel command
1198 line. By default it scans the low 64k of memory every 60
1199 seconds; see the memory_corruption_check_size and
1200 memory_corruption_check_period parameters in
1201 Documentation/kernel-parameters.txt to adjust this.
1203 When enabled with the default parameters, this option has
1204 almost no overhead, as it reserves a relatively small amount
1205 of memory and scans it infrequently. It both detects corruption
1206 and prevents it from affecting the running system.
1208 It is, however, intended as a diagnostic tool; if repeatable
1209 BIOS-originated corruption always affects the same memory,
1210 you can use memmap= to prevent the kernel from using that
1213 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1214 bool "Set the default setting of memory_corruption_check"
1215 depends on X86_CHECK_BIOS_CORRUPTION
1218 Set whether the default state of memory_corruption_check is
1221 config X86_RESERVE_LOW_64K
1222 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1225 Reserve the first 64K of physical RAM on BIOSes that are known
1226 to potentially corrupt that memory range. A numbers of BIOSes are
1227 known to utilize this area during suspend/resume, so it must not
1228 be used by the kernel.
1230 Set this to N if you are absolutely sure that you trust the BIOS
1231 to get all its memory reservations and usages right.
1233 If you have doubts about the BIOS (e.g. suspend/resume does not
1234 work or there's kernel crashes after certain hardware hotplug
1235 events) and it's not AMI or Phoenix, then you might want to enable
1236 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1237 corruption patterns.
1241 config MATH_EMULATION
1243 prompt "Math emulation" if X86_32
1245 Linux can emulate a math coprocessor (used for floating point
1246 operations) if you don't have one. 486DX and Pentium processors have
1247 a math coprocessor built in, 486SX and 386 do not, unless you added
1248 a 487DX or 387, respectively. (The messages during boot time can
1249 give you some hints here ["man dmesg"].) Everyone needs either a
1250 coprocessor or this emulation.
1252 If you don't have a math coprocessor, you need to say Y here; if you
1253 say Y here even though you have a coprocessor, the coprocessor will
1254 be used nevertheless. (This behavior can be changed with the kernel
1255 command line option "no387", which comes handy if your coprocessor
1256 is broken. Try "man bootparam" or see the documentation of your boot
1257 loader (lilo or loadlin) about how to pass options to the kernel at
1258 boot time.) This means that it is a good idea to say Y here if you
1259 intend to use this kernel on different machines.
1261 More information about the internals of the Linux math coprocessor
1262 emulation can be found in <file:arch/x86/math-emu/README>.
1264 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1265 kernel, it won't hurt.
1268 bool "MTRR (Memory Type Range Register) support"
1270 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1271 the Memory Type Range Registers (MTRRs) may be used to control
1272 processor access to memory ranges. This is most useful if you have
1273 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1274 allows bus write transfers to be combined into a larger transfer
1275 before bursting over the PCI/AGP bus. This can increase performance
1276 of image write operations 2.5 times or more. Saying Y here creates a
1277 /proc/mtrr file which may be used to manipulate your processor's
1278 MTRRs. Typically the X server should use this.
1280 This code has a reasonably generic interface so that similar
1281 control registers on other processors can be easily supported
1284 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1285 Registers (ARRs) which provide a similar functionality to MTRRs. For
1286 these, the ARRs are used to emulate the MTRRs.
1287 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1288 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1289 write-combining. All of these processors are supported by this code
1290 and it makes sense to say Y here if you have one of them.
1292 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1293 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1294 can lead to all sorts of problems, so it's good to say Y here.
1296 You can safely say Y even if your machine doesn't have MTRRs, you'll
1297 just add about 9 KB to your kernel.
1299 See <file:Documentation/x86/mtrr.txt> for more information.
1301 config MTRR_SANITIZER
1303 prompt "MTRR cleanup support"
1306 Convert MTRR layout from continuous to discrete, so X drivers can
1307 add writeback entries.
1309 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1310 The largest mtrr entry size for a continous block can be set with
1315 config MTRR_SANITIZER_ENABLE_DEFAULT
1316 int "MTRR cleanup enable value (0-1)"
1319 depends on MTRR_SANITIZER
1321 Enable mtrr cleanup default value
1323 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1324 int "MTRR cleanup spare reg num (0-7)"
1327 depends on MTRR_SANITIZER
1329 mtrr cleanup spare entries default, it can be changed via
1330 mtrr_spare_reg_nr=N on the kernel command line.
1334 prompt "x86 PAT support"
1337 Use PAT attributes to setup page level cache control.
1339 PATs are the modern equivalents of MTRRs and are much more
1340 flexible than MTRRs.
1342 Say N here if you see bootup problems (boot crash, boot hang,
1343 spontaneous reboots) or a non-working video driver.
1348 bool "EFI runtime service support"
1351 This enables the kernel to use EFI runtime services that are
1352 available (such as the EFI variable services).
1354 This option is only useful on systems that have EFI firmware.
1355 In addition, you should use the latest ELILO loader available
1356 at <http://elilo.sourceforge.net> in order to take advantage
1357 of EFI runtime services. However, even with this option, the
1358 resultant kernel should continue to boot on existing non-EFI
1363 prompt "Enable seccomp to safely compute untrusted bytecode"
1365 This kernel feature is useful for number crunching applications
1366 that may need to compute untrusted bytecode during their
1367 execution. By using pipes or other transports made available to
1368 the process as file descriptors supporting the read/write
1369 syscalls, it's possible to isolate those applications in
1370 their own address space using seccomp. Once seccomp is
1371 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1372 and the task is only allowed to execute a few safe syscalls
1373 defined by each seccomp mode.
1375 If unsure, say Y. Only embedded should say N here.
1377 config CC_STACKPROTECTOR_ALL
1380 config CC_STACKPROTECTOR
1381 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1382 select CC_STACKPROTECTOR_ALL
1384 This option turns on the -fstack-protector GCC feature. This
1385 feature puts, at the beginning of functions, a canary value on
1386 the stack just before the return address, and validates
1387 the value just before actually returning. Stack based buffer
1388 overflows (that need to overwrite this return address) now also
1389 overwrite the canary, which gets detected and the attack is then
1390 neutralized via a kernel panic.
1392 This feature requires gcc version 4.2 or above, or a distribution
1393 gcc with the feature backported. Older versions are automatically
1394 detected and for those versions, this configuration option is
1395 ignored. (and a warning is printed during bootup)
1397 source kernel/Kconfig.hz
1400 bool "kexec system call"
1402 kexec is a system call that implements the ability to shutdown your
1403 current kernel, and to start another kernel. It is like a reboot
1404 but it is independent of the system firmware. And like a reboot
1405 you can start any kernel with it, not just Linux.
1407 The name comes from the similarity to the exec system call.
1409 It is an ongoing process to be certain the hardware in a machine
1410 is properly shutdown, so do not be surprised if this code does not
1411 initially work for you. It may help to enable device hotplugging
1412 support. As of this writing the exact hardware interface is
1413 strongly in flux, so no good recommendation can be made.
1416 bool "kernel crash dumps"
1417 depends on X86_64 || (X86_32 && HIGHMEM)
1419 Generate crash dump after being started by kexec.
1420 This should be normally only set in special crash dump kernels
1421 which are loaded in the main kernel with kexec-tools into
1422 a specially reserved region and then later executed after
1423 a crash by kdump/kexec. The crash dump kernel must be compiled
1424 to a memory address not used by the main kernel or BIOS using
1425 PHYSICAL_START, or it must be built as a relocatable image
1426 (CONFIG_RELOCATABLE=y).
1427 For more details see Documentation/kdump/kdump.txt
1430 bool "kexec jump (EXPERIMENTAL)"
1431 depends on EXPERIMENTAL
1432 depends on KEXEC && HIBERNATION && X86_32
1434 Jump between original kernel and kexeced kernel and invoke
1435 code in physical address mode via KEXEC
1437 config PHYSICAL_START
1438 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1439 default "0x1000000" if X86_NUMAQ
1440 default "0x200000" if X86_64
1443 This gives the physical address where the kernel is loaded.
1445 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1446 bzImage will decompress itself to above physical address and
1447 run from there. Otherwise, bzImage will run from the address where
1448 it has been loaded by the boot loader and will ignore above physical
1451 In normal kdump cases one does not have to set/change this option
1452 as now bzImage can be compiled as a completely relocatable image
1453 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1454 address. This option is mainly useful for the folks who don't want
1455 to use a bzImage for capturing the crash dump and want to use a
1456 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1457 to be specifically compiled to run from a specific memory area
1458 (normally a reserved region) and this option comes handy.
1460 So if you are using bzImage for capturing the crash dump, leave
1461 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1462 Otherwise if you plan to use vmlinux for capturing the crash dump
1463 change this value to start of the reserved region (Typically 16MB
1464 0x1000000). In other words, it can be set based on the "X" value as
1465 specified in the "crashkernel=YM@XM" command line boot parameter
1466 passed to the panic-ed kernel. Typically this parameter is set as
1467 crashkernel=64M@16M. Please take a look at
1468 Documentation/kdump/kdump.txt for more details about crash dumps.
1470 Usage of bzImage for capturing the crash dump is recommended as
1471 one does not have to build two kernels. Same kernel can be used
1472 as production kernel and capture kernel. Above option should have
1473 gone away after relocatable bzImage support is introduced. But it
1474 is present because there are users out there who continue to use
1475 vmlinux for dump capture. This option should go away down the
1478 Don't change this unless you know what you are doing.
1481 bool "Build a relocatable kernel (EXPERIMENTAL)"
1482 depends on EXPERIMENTAL
1484 This builds a kernel image that retains relocation information
1485 so it can be loaded someplace besides the default 1MB.
1486 The relocations tend to make the kernel binary about 10% larger,
1487 but are discarded at runtime.
1489 One use is for the kexec on panic case where the recovery kernel
1490 must live at a different physical address than the primary
1493 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1494 it has been loaded at and the compile time physical address
1495 (CONFIG_PHYSICAL_START) is ignored.
1497 config PHYSICAL_ALIGN
1499 prompt "Alignment value to which kernel should be aligned" if X86_32
1500 default "0x100000" if X86_32
1501 default "0x200000" if X86_64
1502 range 0x2000 0x400000
1504 This value puts the alignment restrictions on physical address
1505 where kernel is loaded and run from. Kernel is compiled for an
1506 address which meets above alignment restriction.
1508 If bootloader loads the kernel at a non-aligned address and
1509 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1510 address aligned to above value and run from there.
1512 If bootloader loads the kernel at a non-aligned address and
1513 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1514 load address and decompress itself to the address it has been
1515 compiled for and run from there. The address for which kernel is
1516 compiled already meets above alignment restrictions. Hence the
1517 end result is that kernel runs from a physical address meeting
1518 above alignment restrictions.
1520 Don't change this unless you know what you are doing.
1523 bool "Support for hot-pluggable CPUs"
1524 depends on SMP && HOTPLUG
1526 Say Y here to allow turning CPUs off and on. CPUs can be
1527 controlled through /sys/devices/system/cpu.
1528 ( Note: power management support will enable this option
1529 automatically on SMP systems. )
1530 Say N if you want to disable CPU hotplug.
1534 prompt "Compat VDSO support"
1535 depends on X86_32 || IA32_EMULATION
1537 Map the 32-bit VDSO to the predictable old-style address too.
1539 Say N here if you are running a sufficiently recent glibc
1540 version (2.3.3 or later), to remove the high-mapped
1541 VDSO mapping and to exclusively use the randomized VDSO.
1546 bool "Built-in kernel command line"
1549 Allow for specifying boot arguments to the kernel at
1550 build time. On some systems (e.g. embedded ones), it is
1551 necessary or convenient to provide some or all of the
1552 kernel boot arguments with the kernel itself (that is,
1553 to not rely on the boot loader to provide them.)
1555 To compile command line arguments into the kernel,
1556 set this option to 'Y', then fill in the
1557 the boot arguments in CONFIG_CMDLINE.
1559 Systems with fully functional boot loaders (i.e. non-embedded)
1560 should leave this option set to 'N'.
1563 string "Built-in kernel command string"
1564 depends on CMDLINE_BOOL
1567 Enter arguments here that should be compiled into the kernel
1568 image and used at boot time. If the boot loader provides a
1569 command line at boot time, it is appended to this string to
1570 form the full kernel command line, when the system boots.
1572 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1573 change this behavior.
1575 In most cases, the command line (whether built-in or provided
1576 by the boot loader) should specify the device for the root
1579 config CMDLINE_OVERRIDE
1580 bool "Built-in command line overrides boot loader arguments"
1582 depends on CMDLINE_BOOL
1584 Set this option to 'Y' to have the kernel ignore the boot loader
1585 command line, and use ONLY the built-in command line.
1587 This is used to work around broken boot loaders. This should
1588 be set to 'N' under normal conditions.
1592 config ARCH_ENABLE_MEMORY_HOTPLUG
1594 depends on X86_64 || (X86_32 && HIGHMEM)
1596 config ARCH_ENABLE_MEMORY_HOTREMOVE
1598 depends on MEMORY_HOTPLUG
1600 config HAVE_ARCH_EARLY_PFN_TO_NID
1604 menu "Power management and ACPI options"
1606 config ARCH_HIBERNATION_HEADER
1608 depends on X86_64 && HIBERNATION
1610 source "kernel/power/Kconfig"
1612 source "drivers/acpi/Kconfig"
1617 depends on APM || APM_MODULE
1620 tristate "APM (Advanced Power Management) BIOS support"
1621 depends on X86_32 && PM_SLEEP
1623 APM is a BIOS specification for saving power using several different
1624 techniques. This is mostly useful for battery powered laptops with
1625 APM compliant BIOSes. If you say Y here, the system time will be
1626 reset after a RESUME operation, the /proc/apm device will provide
1627 battery status information, and user-space programs will receive
1628 notification of APM "events" (e.g. battery status change).
1630 If you select "Y" here, you can disable actual use of the APM
1631 BIOS by passing the "apm=off" option to the kernel at boot time.
1633 Note that the APM support is almost completely disabled for
1634 machines with more than one CPU.
1636 In order to use APM, you will need supporting software. For location
1637 and more information, read <file:Documentation/power/pm.txt> and the
1638 Battery Powered Linux mini-HOWTO, available from
1639 <http://www.tldp.org/docs.html#howto>.
1641 This driver does not spin down disk drives (see the hdparm(8)
1642 manpage ("man 8 hdparm") for that), and it doesn't turn off
1643 VESA-compliant "green" monitors.
1645 This driver does not support the TI 4000M TravelMate and the ACER
1646 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1647 desktop machines also don't have compliant BIOSes, and this driver
1648 may cause those machines to panic during the boot phase.
1650 Generally, if you don't have a battery in your machine, there isn't
1651 much point in using this driver and you should say N. If you get
1652 random kernel OOPSes or reboots that don't seem to be related to
1653 anything, try disabling/enabling this option (or disabling/enabling
1656 Some other things you should try when experiencing seemingly random,
1659 1) make sure that you have enough swap space and that it is
1661 2) pass the "no-hlt" option to the kernel
1662 3) switch on floating point emulation in the kernel and pass
1663 the "no387" option to the kernel
1664 4) pass the "floppy=nodma" option to the kernel
1665 5) pass the "mem=4M" option to the kernel (thereby disabling
1666 all but the first 4 MB of RAM)
1667 6) make sure that the CPU is not over clocked.
1668 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1669 8) disable the cache from your BIOS settings
1670 9) install a fan for the video card or exchange video RAM
1671 10) install a better fan for the CPU
1672 11) exchange RAM chips
1673 12) exchange the motherboard.
1675 To compile this driver as a module, choose M here: the
1676 module will be called apm.
1680 config APM_IGNORE_USER_SUSPEND
1681 bool "Ignore USER SUSPEND"
1683 This option will ignore USER SUSPEND requests. On machines with a
1684 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1685 series notebooks, it is necessary to say Y because of a BIOS bug.
1687 config APM_DO_ENABLE
1688 bool "Enable PM at boot time"
1690 Enable APM features at boot time. From page 36 of the APM BIOS
1691 specification: "When disabled, the APM BIOS does not automatically
1692 power manage devices, enter the Standby State, enter the Suspend
1693 State, or take power saving steps in response to CPU Idle calls."
1694 This driver will make CPU Idle calls when Linux is idle (unless this
1695 feature is turned off -- see "Do CPU IDLE calls", below). This
1696 should always save battery power, but more complicated APM features
1697 will be dependent on your BIOS implementation. You may need to turn
1698 this option off if your computer hangs at boot time when using APM
1699 support, or if it beeps continuously instead of suspending. Turn
1700 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1701 T400CDT. This is off by default since most machines do fine without
1705 bool "Make CPU Idle calls when idle"
1707 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1708 On some machines, this can activate improved power savings, such as
1709 a slowed CPU clock rate, when the machine is idle. These idle calls
1710 are made after the idle loop has run for some length of time (e.g.,
1711 333 mS). On some machines, this will cause a hang at boot time or
1712 whenever the CPU becomes idle. (On machines with more than one CPU,
1713 this option does nothing.)
1715 config APM_DISPLAY_BLANK
1716 bool "Enable console blanking using APM"
1718 Enable console blanking using the APM. Some laptops can use this to
1719 turn off the LCD backlight when the screen blanker of the Linux
1720 virtual console blanks the screen. Note that this is only used by
1721 the virtual console screen blanker, and won't turn off the backlight
1722 when using the X Window system. This also doesn't have anything to
1723 do with your VESA-compliant power-saving monitor. Further, this
1724 option doesn't work for all laptops -- it might not turn off your
1725 backlight at all, or it might print a lot of errors to the console,
1726 especially if you are using gpm.
1728 config APM_ALLOW_INTS
1729 bool "Allow interrupts during APM BIOS calls"
1731 Normally we disable external interrupts while we are making calls to
1732 the APM BIOS as a measure to lessen the effects of a badly behaving
1733 BIOS implementation. The BIOS should reenable interrupts if it
1734 needs to. Unfortunately, some BIOSes do not -- especially those in
1735 many of the newer IBM Thinkpads. If you experience hangs when you
1736 suspend, try setting this to Y. Otherwise, say N.
1740 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1742 source "drivers/cpuidle/Kconfig"
1744 source "drivers/idle/Kconfig"
1749 menu "Bus options (PCI etc.)"
1754 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1756 Find out whether you have a PCI motherboard. PCI is the name of a
1757 bus system, i.e. the way the CPU talks to the other stuff inside
1758 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1759 VESA. If you have PCI, say Y, otherwise N.
1762 prompt "PCI access mode"
1763 depends on X86_32 && PCI
1766 On PCI systems, the BIOS can be used to detect the PCI devices and
1767 determine their configuration. However, some old PCI motherboards
1768 have BIOS bugs and may crash if this is done. Also, some embedded
1769 PCI-based systems don't have any BIOS at all. Linux can also try to
1770 detect the PCI hardware directly without using the BIOS.
1772 With this option, you can specify how Linux should detect the
1773 PCI devices. If you choose "BIOS", the BIOS will be used,
1774 if you choose "Direct", the BIOS won't be used, and if you
1775 choose "MMConfig", then PCI Express MMCONFIG will be used.
1776 If you choose "Any", the kernel will try MMCONFIG, then the
1777 direct access method and falls back to the BIOS if that doesn't
1778 work. If unsure, go with the default, which is "Any".
1783 config PCI_GOMMCONFIG
1800 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1802 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1805 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1809 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1813 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1820 bool "Support mmconfig PCI config space access"
1821 depends on X86_64 && PCI && ACPI
1824 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1825 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1827 DMA remapping (DMAR) devices support enables independent address
1828 translations for Direct Memory Access (DMA) from devices.
1829 These DMA remapping devices are reported via ACPI tables
1830 and include PCI device scope covered by these DMA
1833 config DMAR_DEFAULT_ON
1835 prompt "Enable DMA Remapping Devices by default"
1838 Selecting this option will enable a DMAR device at boot time if
1839 one is found. If this option is not selected, DMAR support can
1840 be enabled by passing intel_iommu=on to the kernel. It is
1841 recommended you say N here while the DMAR code remains
1846 prompt "Support for Graphics workaround"
1849 Current Graphics drivers tend to use physical address
1850 for DMA and avoid using DMA APIs. Setting this config
1851 option permits the IOMMU driver to set a unity map for
1852 all the OS-visible memory. Hence the driver can continue
1853 to use physical addresses for DMA.
1855 config DMAR_FLOPPY_WA
1859 Floppy disk drivers are know to bypass DMA API calls
1860 thereby failing to work when IOMMU is enabled. This
1861 workaround will setup a 1:1 mapping for the first
1862 16M to make floppy (an ISA device) work.
1865 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1866 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1869 Supports Interrupt remapping for IO-APIC and MSI devices.
1870 To use x2apic mode in the CPU's which support x2APIC enhancements or
1871 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1873 source "drivers/pci/pcie/Kconfig"
1875 source "drivers/pci/Kconfig"
1877 # x86_64 have no ISA slots, but do have ISA-style DMA.
1886 Find out whether you have ISA slots on your motherboard. ISA is the
1887 name of a bus system, i.e. the way the CPU talks to the other stuff
1888 inside your box. Other bus systems are PCI, EISA, MicroChannel
1889 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1890 newer boards don't support it. If you have ISA, say Y, otherwise N.
1896 The Extended Industry Standard Architecture (EISA) bus was
1897 developed as an open alternative to the IBM MicroChannel bus.
1899 The EISA bus provided some of the features of the IBM MicroChannel
1900 bus while maintaining backward compatibility with cards made for
1901 the older ISA bus. The EISA bus saw limited use between 1988 and
1902 1995 when it was made obsolete by the PCI bus.
1904 Say Y here if you are building a kernel for an EISA-based machine.
1908 source "drivers/eisa/Kconfig"
1913 MicroChannel Architecture is found in some IBM PS/2 machines and
1914 laptops. It is a bus system similar to PCI or ISA. See
1915 <file:Documentation/mca.txt> (and especially the web page given
1916 there) before attempting to build an MCA bus kernel.
1918 source "drivers/mca/Kconfig"
1921 tristate "NatSemi SCx200 support"
1923 This provides basic support for National Semiconductor's
1924 (now AMD's) Geode processors. The driver probes for the
1925 PCI-IDs of several on-chip devices, so its a good dependency
1926 for other scx200_* drivers.
1928 If compiled as a module, the driver is named scx200.
1930 config SCx200HR_TIMER
1931 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1932 depends on SCx200 && GENERIC_TIME
1935 This driver provides a clocksource built upon the on-chip
1936 27MHz high-resolution timer. Its also a workaround for
1937 NSC Geode SC-1100's buggy TSC, which loses time when the
1938 processor goes idle (as is done by the scheduler). The
1939 other workaround is idle=poll boot option.
1941 config GEODE_MFGPT_TIMER
1943 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1944 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1946 This driver provides a clock event source based on the MFGPT
1947 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1948 MFGPTs have a better resolution and max interval than the
1949 generic PIT, and are suitable for use as high-res timers.
1952 bool "One Laptop Per Child support"
1955 Add support for detecting the unique features of the OLPC
1962 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1964 source "drivers/pcmcia/Kconfig"
1966 source "drivers/pci/hotplug/Kconfig"
1971 menu "Executable file formats / Emulations"
1973 source "fs/Kconfig.binfmt"
1975 config IA32_EMULATION
1976 bool "IA32 Emulation"
1978 select COMPAT_BINFMT_ELF
1980 Include code to run 32-bit programs under a 64-bit kernel. You should
1981 likely turn this on, unless you're 100% sure that you don't have any
1982 32-bit programs left.
1985 tristate "IA32 a.out support"
1986 depends on IA32_EMULATION
1988 Support old a.out binaries in the 32bit emulation.
1992 depends on IA32_EMULATION
1994 config COMPAT_FOR_U64_ALIGNMENT
1998 config SYSVIPC_COMPAT
2000 depends on COMPAT && SYSVIPC
2005 config HAVE_ATOMIC_IOMAP
2009 source "net/Kconfig"
2011 source "drivers/Kconfig"
2013 source "drivers/firmware/Kconfig"
2017 source "arch/x86/Kconfig.debug"
2019 source "security/Kconfig"
2021 source "crypto/Kconfig"
2023 source "arch/x86/kvm/Kconfig"
2025 source "lib/Kconfig"