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_PERF_COUNTERS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_SYSCALL_TRACEPOINTS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_DMA_API_DEBUG
49 select HAVE_KERNEL_GZIP
50 select HAVE_KERNEL_BZIP2
51 select HAVE_KERNEL_LZMA
52 select HAVE_HW_BREAKPOINT
53 select HAVE_ARCH_KMEMCHECK
57 default "elf32-i386" if X86_32
58 default "elf64-x86-64" if X86_64
62 default "arch/x86/configs/i386_defconfig" if X86_32
63 default "arch/x86/configs/x86_64_defconfig" if X86_64
68 config GENERIC_CMOS_UPDATE
71 config CLOCKSOURCE_WATCHDOG
74 config GENERIC_CLOCKEVENTS
77 config GENERIC_CLOCKEVENTS_BROADCAST
79 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
81 config LOCKDEP_SUPPORT
84 config STACKTRACE_SUPPORT
87 config HAVE_LATENCYTOP_SUPPORT
90 config FAST_CMPXCHG_LOCAL
103 config GENERIC_ISA_DMA
112 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
114 config GENERIC_BUG_RELATIVE_POINTERS
117 config GENERIC_HWEIGHT
123 config ARCH_MAY_HAVE_PC_FDC
126 config RWSEM_GENERIC_SPINLOCK
129 config RWSEM_XCHGADD_ALGORITHM
132 config ARCH_HAS_CPU_IDLE_WAIT
135 config GENERIC_CALIBRATE_DELAY
138 config GENERIC_TIME_VSYSCALL
142 config ARCH_HAS_CPU_RELAX
145 config ARCH_HAS_DEFAULT_IDLE
148 config ARCH_HAS_CACHE_LINE_SIZE
151 config HAVE_SETUP_PER_CPU_AREA
154 config HAVE_DYNAMIC_PER_CPU_AREA
157 config HAVE_CPUMASK_OF_CPU_MAP
160 config ARCH_HIBERNATION_POSSIBLE
163 config ARCH_SUSPEND_POSSIBLE
170 config ARCH_POPULATES_NODE_MAP
177 config ARCH_SUPPORTS_OPTIMIZED_INLINING
180 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
183 # Use the generic interrupt handling code in kernel/irq/:
184 config GENERIC_HARDIRQS
188 config GENERIC_HARDIRQS_NO__DO_IRQ
191 config GENERIC_IRQ_PROBE
195 config GENERIC_PENDING_IRQ
197 depends on GENERIC_HARDIRQS && SMP
200 config USE_GENERIC_SMP_HELPERS
206 depends on X86_32 && SMP
210 depends on X86_64 && SMP
217 config X86_TRAMPOLINE
219 depends on SMP || (64BIT && ACPI_SLEEP)
222 config X86_32_LAZY_GS
224 depends on X86_32 && !CC_STACKPROTECTOR
228 source "init/Kconfig"
229 source "kernel/Kconfig.freezer"
231 menu "Processor type and features"
233 source "kernel/time/Kconfig"
236 bool "Symmetric multi-processing support"
238 This enables support for systems with more than one CPU. If you have
239 a system with only one CPU, like most personal computers, say N. If
240 you have a system with more than one CPU, say Y.
242 If you say N here, the kernel will run on single and multiprocessor
243 machines, but will use only one CPU of a multiprocessor machine. If
244 you say Y here, the kernel will run on many, but not all,
245 singleprocessor machines. On a singleprocessor machine, the kernel
246 will run faster if you say N here.
248 Note that if you say Y here and choose architecture "586" or
249 "Pentium" under "Processor family", the kernel will not work on 486
250 architectures. Similarly, multiprocessor kernels for the "PPro"
251 architecture may not work on all Pentium based boards.
253 People using multiprocessor machines who say Y here should also say
254 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
255 Management" code will be disabled if you say Y here.
257 See also <file:Documentation/i386/IO-APIC.txt>,
258 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
259 <http://www.tldp.org/docs.html#howto>.
261 If you don't know what to do here, say N.
264 bool "Support x2apic"
265 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
267 This enables x2apic support on CPUs that have this feature.
269 This allows 32-bit apic IDs (so it can support very large systems),
270 and accesses the local apic via MSRs not via mmio.
272 If you don't know what to do here, say N.
275 bool "Support sparse irq numbering"
276 depends on PCI_MSI || HT_IRQ
278 This enables support for sparse irqs. This is useful for distro
279 kernels that want to define a high CONFIG_NR_CPUS value but still
280 want to have low kernel memory footprint on smaller machines.
282 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
283 out the irq_desc[] array in a more NUMA-friendly way. )
285 If you don't know what to do here, say N.
289 depends on SPARSE_IRQ && NUMA
292 bool "Enable MPS table" if ACPI
294 depends on X86_LOCAL_APIC
296 For old smp systems that do not have proper acpi support. Newer systems
297 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
300 bool "Support for big SMP systems with more than 8 CPUs"
301 depends on X86_32 && SMP
303 This option is needed for the systems that have more than 8 CPUs
306 config X86_EXTENDED_PLATFORM
307 bool "Support for extended (non-PC) x86 platforms"
310 If you disable this option then the kernel will only support
311 standard PC platforms. (which covers the vast majority of
314 If you enable this option then you'll be able to select support
315 for the following (non-PC) 32 bit x86 platforms:
319 SGI 320/540 (Visual Workstation)
320 Summit/EXA (IBM x440)
321 Unisys ES7000 IA32 series
323 If you have one of these systems, or if you want to build a
324 generic distribution kernel, say Y here - otherwise say N.
328 config X86_EXTENDED_PLATFORM
329 bool "Support for extended (non-PC) x86 platforms"
332 If you disable this option then the kernel will only support
333 standard PC platforms. (which covers the vast majority of
336 If you enable this option then you'll be able to select support
337 for the following (non-PC) 64 bit x86 platforms:
341 If you have one of these systems, or if you want to build a
342 generic distribution kernel, say Y here - otherwise say N.
344 # This is an alphabetically sorted list of 64 bit extended platforms
345 # Please maintain the alphabetic order if and when there are additions
350 depends on X86_64 && PCI
351 depends on X86_EXTENDED_PLATFORM
353 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
354 supposed to run on these EM64T-based machines. Only choose this option
355 if you have one of these machines.
358 bool "SGI Ultraviolet"
360 depends on X86_EXTENDED_PLATFORM
362 depends on X86_X2APIC
364 This option is needed in order to support SGI Ultraviolet systems.
365 If you don't have one of these, you should say N here.
367 # Following is an alphabetically sorted list of 32 bit extended platforms
368 # Please maintain the alphabetic order if and when there are additions
373 depends on X86_EXTENDED_PLATFORM
375 Select this for an AMD Elan processor.
377 Do not use this option for K6/Athlon/Opteron processors!
379 If unsure, choose "PC-compatible" instead.
382 bool "RDC R-321x SoC"
384 depends on X86_EXTENDED_PLATFORM
386 select X86_REBOOTFIXUPS
388 This option is needed for RDC R-321x system-on-chip, also known
390 If you don't have one of these chips, you should say N here.
392 config X86_32_NON_STANDARD
393 bool "Support non-standard 32-bit SMP architectures"
394 depends on X86_32 && SMP
395 depends on X86_EXTENDED_PLATFORM
397 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
398 subarchitectures. It is intended for a generic binary kernel.
399 if you select them all, kernel will probe it one by one. and will
402 # Alphabetically sorted list of Non standard 32 bit platforms
405 bool "NUMAQ (IBM/Sequent)"
406 depends on X86_32_NON_STANDARD
410 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
411 NUMA multiquad box. This changes the way that processors are
412 bootstrapped, and uses Clustered Logical APIC addressing mode instead
413 of Flat Logical. You will need a new lynxer.elf file to flash your
414 firmware with - send email to <Martin.Bligh@us.ibm.com>.
417 bool "SGI 320/540 (Visual Workstation)"
418 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
419 depends on X86_32_NON_STANDARD
421 The SGI Visual Workstation series is an IA32-based workstation
422 based on SGI systems chips with some legacy PC hardware attached.
424 Say Y here to create a kernel to run on the SGI 320 or 540.
426 A kernel compiled for the Visual Workstation will run on general
427 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
430 bool "Summit/EXA (IBM x440)"
431 depends on X86_32_NON_STANDARD
433 This option is needed for IBM systems that use the Summit/EXA chipset.
434 In particular, it is needed for the x440.
437 bool "Unisys ES7000 IA32 series"
438 depends on X86_32_NON_STANDARD && X86_BIGSMP
440 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
441 supposed to run on an IA32-based Unisys ES7000 system.
443 config SCHED_OMIT_FRAME_POINTER
445 prompt "Single-depth WCHAN output"
448 Calculate simpler /proc/<PID>/wchan values. If this option
449 is disabled then wchan values will recurse back to the
450 caller function. This provides more accurate wchan values,
451 at the expense of slightly more scheduling overhead.
453 If in doubt, say "Y".
455 menuconfig PARAVIRT_GUEST
456 bool "Paravirtualized guest support"
458 Say Y here to get to see options related to running Linux under
459 various hypervisors. This option alone does not add any kernel code.
461 If you say N, all options in this submenu will be skipped and disabled.
465 source "arch/x86/xen/Kconfig"
468 bool "VMI Guest support"
472 VMI provides a paravirtualized interface to the VMware ESX server
473 (it could be used by other hypervisors in theory too, but is not
474 at the moment), by linking the kernel to a GPL-ed ROM module
475 provided by the hypervisor.
478 bool "KVM paravirtualized clock"
480 select PARAVIRT_CLOCK
482 Turning on this option will allow you to run a paravirtualized clock
483 when running over the KVM hypervisor. Instead of relying on a PIT
484 (or probably other) emulation by the underlying device model, the host
485 provides the guest with timing infrastructure such as time of day, and
489 bool "KVM Guest support"
492 This option enables various optimizations for running under the KVM
495 source "arch/x86/lguest/Kconfig"
498 bool "Enable paravirtualization code"
500 This changes the kernel so it can modify itself when it is run
501 under a hypervisor, potentially improving performance significantly
502 over full virtualization. However, when run without a hypervisor
503 the kernel is theoretically slower and slightly larger.
505 config PARAVIRT_SPINLOCKS
506 bool "Paravirtualization layer for spinlocks"
507 depends on PARAVIRT && SMP && EXPERIMENTAL
509 Paravirtualized spinlocks allow a pvops backend to replace the
510 spinlock implementation with something virtualization-friendly
511 (for example, block the virtual CPU rather than spinning).
513 Unfortunately the downside is an up to 5% performance hit on
514 native kernels, with various workloads.
516 If you are unsure how to answer this question, answer N.
518 config PARAVIRT_CLOCK
524 config PARAVIRT_DEBUG
525 bool "paravirt-ops debugging"
526 depends on PARAVIRT && DEBUG_KERNEL
528 Enable to debug paravirt_ops internals. Specifically, BUG if
529 a paravirt_op is missing when it is called.
534 This option adds a kernel parameter 'memtest', which allows memtest
536 memtest=0, mean disabled; -- default
537 memtest=1, mean do 1 test pattern;
539 memtest=4, mean do 4 test patterns.
540 If you are unsure how to answer this question, answer N.
542 config X86_SUMMIT_NUMA
544 depends on X86_32 && NUMA && X86_32_NON_STANDARD
546 config X86_CYCLONE_TIMER
548 depends on X86_32_NON_STANDARD
550 source "arch/x86/Kconfig.cpu"
554 prompt "HPET Timer Support" if X86_32
556 Use the IA-PC HPET (High Precision Event Timer) to manage
557 time in preference to the PIT and RTC, if a HPET is
559 HPET is the next generation timer replacing legacy 8254s.
560 The HPET provides a stable time base on SMP
561 systems, unlike the TSC, but it is more expensive to access,
562 as it is off-chip. You can find the HPET spec at
563 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
565 You can safely choose Y here. However, HPET will only be
566 activated if the platform and the BIOS support this feature.
567 Otherwise the 8254 will be used for timing services.
569 Choose N to continue using the legacy 8254 timer.
571 config HPET_EMULATE_RTC
573 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
575 # Mark as embedded because too many people got it wrong.
576 # The code disables itself when not needed.
579 bool "Enable DMI scanning" if EMBEDDED
581 Enabled scanning of DMI to identify machine quirks. Say Y
582 here unless you have verified that your setup is not
583 affected by entries in the DMI blacklist. Required by PNP
587 bool "GART IOMMU support" if EMBEDDED
591 depends on X86_64 && PCI
593 Support for full DMA access of devices with 32bit memory access only
594 on systems with more than 3GB. This is usually needed for USB,
595 sound, many IDE/SATA chipsets and some other devices.
596 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
597 based hardware IOMMU and a software bounce buffer based IOMMU used
598 on Intel systems and as fallback.
599 The code is only active when needed (enough memory and limited
600 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
604 bool "IBM Calgary IOMMU support"
606 depends on X86_64 && PCI && EXPERIMENTAL
608 Support for hardware IOMMUs in IBM's xSeries x366 and x460
609 systems. Needed to run systems with more than 3GB of memory
610 properly with 32-bit PCI devices that do not support DAC
611 (Double Address Cycle). Calgary also supports bus level
612 isolation, where all DMAs pass through the IOMMU. This
613 prevents them from going anywhere except their intended
614 destination. This catches hard-to-find kernel bugs and
615 mis-behaving drivers and devices that do not use the DMA-API
616 properly to set up their DMA buffers. The IOMMU can be
617 turned off at boot time with the iommu=off parameter.
618 Normally the kernel will make the right choice by itself.
621 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
623 prompt "Should Calgary be enabled by default?"
624 depends on CALGARY_IOMMU
626 Should Calgary be enabled by default? if you choose 'y', Calgary
627 will be used (if it exists). If you choose 'n', Calgary will not be
628 used even if it exists. If you choose 'n' and would like to use
629 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
633 bool "AMD IOMMU support"
636 depends on X86_64 && PCI && ACPI
638 With this option you can enable support for AMD IOMMU hardware in
639 your system. An IOMMU is a hardware component which provides
640 remapping of DMA memory accesses from devices. With an AMD IOMMU you
641 can isolate the the DMA memory of different devices and protect the
642 system from misbehaving device drivers or hardware.
644 You can find out if your system has an AMD IOMMU if you look into
645 your BIOS for an option to enable it or if you have an IVRS ACPI
648 config AMD_IOMMU_STATS
649 bool "Export AMD IOMMU statistics to debugfs"
653 This option enables code in the AMD IOMMU driver to collect various
654 statistics about whats happening in the driver and exports that
655 information to userspace via debugfs.
658 # need this always selected by IOMMU for the VIA workaround
662 Support for software bounce buffers used on x86-64 systems
663 which don't have a hardware IOMMU (e.g. the current generation
664 of Intel's x86-64 CPUs). Using this PCI devices which can only
665 access 32-bits of memory can be used on systems with more than
666 3 GB of memory. If unsure, say Y.
669 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
672 def_bool (AMD_IOMMU || DMAR)
675 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
676 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
677 select CPUMASK_OFFSTACK
680 Configure maximum number of CPUS and NUMA Nodes for this architecture.
684 int "Maximum number of CPUs" if SMP && !MAXSMP
685 range 2 8 if SMP && X86_32 && !X86_BIGSMP
686 range 2 512 if SMP && !MAXSMP
688 default "4096" if MAXSMP
689 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
692 This allows you to specify the maximum number of CPUs which this
693 kernel will support. The maximum supported value is 512 and the
694 minimum value which makes sense is 2.
696 This is purely to save memory - each supported CPU adds
697 approximately eight kilobytes to the kernel image.
700 bool "SMT (Hyperthreading) scheduler support"
703 SMT scheduler support improves the CPU scheduler's decision making
704 when dealing with Intel Pentium 4 chips with HyperThreading at a
705 cost of slightly increased overhead in some places. If unsure say
710 prompt "Multi-core scheduler support"
713 Multi-core scheduler support improves the CPU scheduler's decision
714 making when dealing with multi-core CPU chips at a cost of slightly
715 increased overhead in some places. If unsure say N here.
717 source "kernel/Kconfig.preempt"
720 bool "Local APIC support on uniprocessors"
721 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
723 A local APIC (Advanced Programmable Interrupt Controller) is an
724 integrated interrupt controller in the CPU. If you have a single-CPU
725 system which has a processor with a local APIC, you can say Y here to
726 enable and use it. If you say Y here even though your machine doesn't
727 have a local APIC, then the kernel will still run with no slowdown at
728 all. The local APIC supports CPU-generated self-interrupts (timer,
729 performance counters), and the NMI watchdog which detects hard
733 bool "IO-APIC support on uniprocessors"
734 depends on X86_UP_APIC
736 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
737 SMP-capable replacement for PC-style interrupt controllers. Most
738 SMP systems and many recent uniprocessor systems have one.
740 If you have a single-CPU system with an IO-APIC, you can say Y here
741 to use it. If you say Y here even though your machine doesn't have
742 an IO-APIC, then the kernel will still run with no slowdown at all.
744 config X86_LOCAL_APIC
746 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
750 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
752 config X86_VISWS_APIC
754 depends on X86_32 && X86_VISWS
756 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
757 bool "Reroute for broken boot IRQs"
759 depends on X86_IO_APIC
761 This option enables a workaround that fixes a source of
762 spurious interrupts. This is recommended when threaded
763 interrupt handling is used on systems where the generation of
764 superfluous "boot interrupts" cannot be disabled.
766 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
767 entry in the chipset's IO-APIC is masked (as, e.g. the RT
768 kernel does during interrupt handling). On chipsets where this
769 boot IRQ generation cannot be disabled, this workaround keeps
770 the original IRQ line masked so that only the equivalent "boot
771 IRQ" is delivered to the CPUs. The workaround also tells the
772 kernel to set up the IRQ handler on the boot IRQ line. In this
773 way only one interrupt is delivered to the kernel. Otherwise
774 the spurious second interrupt may cause the kernel to bring
775 down (vital) interrupt lines.
777 Only affects "broken" chipsets. Interrupt sharing may be
778 increased on these systems.
781 bool "Machine Check Exception"
783 Machine Check Exception support allows the processor to notify the
784 kernel if it detects a problem (e.g. overheating, component failure).
785 The action the kernel takes depends on the severity of the problem,
786 ranging from a warning message on the console, to halting the machine.
787 Your processor must be a Pentium or newer to support this - check the
788 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
789 have a design flaw which leads to false MCE events - hence MCE is
790 disabled on all P5 processors, unless explicitly enabled with "mce"
791 as a boot argument. Similarly, if MCE is built in and creates a
792 problem on some new non-standard machine, you can boot with "nomce"
793 to disable it. MCE support simply ignores non-MCE processors like
794 the 386 and 486, so nearly everyone can say Y here.
797 depends on X86_32 && X86_MCE
798 bool "Use legacy machine check code (will go away)"
800 select X86_ANCIENT_MCE
802 Use the old i386 machine check code. This is merely intended for
803 testing in a transition period. Try this if you run into any machine
804 check related software problems, but report the problem to
805 linux-kernel. When in doubt say no.
810 default y if (!X86_OLD_MCE && X86_32) || X86_64
814 prompt "Intel MCE features"
815 depends on X86_NEW_MCE && X86_LOCAL_APIC
817 Additional support for intel specific MCE features such as
822 prompt "AMD MCE features"
823 depends on X86_NEW_MCE && X86_LOCAL_APIC
825 Additional support for AMD specific MCE features such as
826 the DRAM Error Threshold.
828 config X86_ANCIENT_MCE
831 prompt "Support for old Pentium 5 / WinChip machine checks"
833 Include support for machine check handling on old Pentium 5 or WinChip
834 systems. These typically need to be enabled explicitely on the command
837 config X86_MCE_THRESHOLD
838 depends on X86_MCE_AMD || X86_MCE_INTEL
842 config X86_MCE_INJECT
843 depends on X86_NEW_MCE
844 tristate "Machine check injector support"
846 Provide support for injecting machine checks for testing purposes.
847 If you don't know what a machine check is and you don't do kernel
848 QA it is safe to say n.
850 config X86_MCE_NONFATAL
851 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
852 depends on X86_OLD_MCE
854 Enabling this feature starts a timer that triggers every 5 seconds which
855 will look at the machine check registers to see if anything happened.
856 Non-fatal problems automatically get corrected (but still logged).
857 Disable this if you don't want to see these messages.
858 Seeing the messages this option prints out may be indicative of dying
859 or out-of-spec (ie, overclocked) hardware.
860 This option only does something on certain CPUs.
861 (AMD Athlon/Duron and Intel Pentium 4)
863 config X86_MCE_P4THERMAL
864 bool "check for P4 thermal throttling interrupt."
865 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
867 Enabling this feature will cause a message to be printed when the P4
868 enters thermal throttling.
870 config X86_THERMAL_VECTOR
872 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
875 bool "Enable VM86 support" if EMBEDDED
879 This option is required by programs like DOSEMU to run 16-bit legacy
880 code on X86 processors. It also may be needed by software like
881 XFree86 to initialize some video cards via BIOS. Disabling this
882 option saves about 6k.
885 tristate "Toshiba Laptop support"
888 This adds a driver to safely access the System Management Mode of
889 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
890 not work on models with a Phoenix BIOS. The System Management Mode
891 is used to set the BIOS and power saving options on Toshiba portables.
893 For information on utilities to make use of this driver see the
894 Toshiba Linux utilities web site at:
895 <http://www.buzzard.org.uk/toshiba/>.
897 Say Y if you intend to run this kernel on a Toshiba portable.
901 tristate "Dell laptop support"
903 This adds a driver to safely access the System Management Mode
904 of the CPU on the Dell Inspiron 8000. The System Management Mode
905 is used to read cpu temperature and cooling fan status and to
906 control the fans on the I8K portables.
908 This driver has been tested only on the Inspiron 8000 but it may
909 also work with other Dell laptops. You can force loading on other
910 models by passing the parameter `force=1' to the module. Use at
913 For information on utilities to make use of this driver see the
914 I8K Linux utilities web site at:
915 <http://people.debian.org/~dz/i8k/>
917 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
920 config X86_REBOOTFIXUPS
921 bool "Enable X86 board specific fixups for reboot"
924 This enables chipset and/or board specific fixups to be done
925 in order to get reboot to work correctly. This is only needed on
926 some combinations of hardware and BIOS. The symptom, for which
927 this config is intended, is when reboot ends with a stalled/hung
930 Currently, the only fixup is for the Geode machines using
931 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
933 Say Y if you want to enable the fixup. Currently, it's safe to
934 enable this option even if you don't need it.
938 tristate "/dev/cpu/microcode - microcode support"
941 If you say Y here, you will be able to update the microcode on
942 certain Intel and AMD processors. The Intel support is for the
943 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
944 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
945 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
946 You will obviously need the actual microcode binary data itself
947 which is not shipped with the Linux kernel.
949 This option selects the general module only, you need to select
950 at least one vendor specific module as well.
952 To compile this driver as a module, choose M here: the
953 module will be called microcode.
955 config MICROCODE_INTEL
956 bool "Intel microcode patch loading support"
961 This options enables microcode patch loading support for Intel
964 For latest news and information on obtaining all the required
965 Intel ingredients for this driver, check:
966 <http://www.urbanmyth.org/microcode/>.
969 bool "AMD microcode patch loading support"
973 If you select this option, microcode patch loading support for AMD
974 processors will be enabled.
976 config MICROCODE_OLD_INTERFACE
981 tristate "/dev/cpu/*/msr - Model-specific register support"
983 This device gives privileged processes access to the x86
984 Model-Specific Registers (MSRs). It is a character device with
985 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
986 MSR accesses are directed to a specific CPU on multi-processor
990 tristate "/dev/cpu/*/cpuid - CPU information support"
992 This device gives processes access to the x86 CPUID instruction to
993 be executed on a specific processor. It is a character device
994 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
998 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
1000 If you select this option, this will provide various x86 CPUs
1001 information through debugfs.
1004 prompt "High Memory Support"
1005 default HIGHMEM4G if !X86_NUMAQ
1006 default HIGHMEM64G if X86_NUMAQ
1011 depends on !X86_NUMAQ
1013 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1014 However, the address space of 32-bit x86 processors is only 4
1015 Gigabytes large. That means that, if you have a large amount of
1016 physical memory, not all of it can be "permanently mapped" by the
1017 kernel. The physical memory that's not permanently mapped is called
1020 If you are compiling a kernel which will never run on a machine with
1021 more than 1 Gigabyte total physical RAM, answer "off" here (default
1022 choice and suitable for most users). This will result in a "3GB/1GB"
1023 split: 3GB are mapped so that each process sees a 3GB virtual memory
1024 space and the remaining part of the 4GB virtual memory space is used
1025 by the kernel to permanently map as much physical memory as
1028 If the machine has between 1 and 4 Gigabytes physical RAM, then
1031 If more than 4 Gigabytes is used then answer "64GB" here. This
1032 selection turns Intel PAE (Physical Address Extension) mode on.
1033 PAE implements 3-level paging on IA32 processors. PAE is fully
1034 supported by Linux, PAE mode is implemented on all recent Intel
1035 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1036 then the kernel will not boot on CPUs that don't support PAE!
1038 The actual amount of total physical memory will either be
1039 auto detected or can be forced by using a kernel command line option
1040 such as "mem=256M". (Try "man bootparam" or see the documentation of
1041 your boot loader (lilo or loadlin) about how to pass options to the
1042 kernel at boot time.)
1044 If unsure, say "off".
1048 depends on !X86_NUMAQ
1050 Select this if you have a 32-bit processor and between 1 and 4
1051 gigabytes of physical RAM.
1055 depends on !M386 && !M486
1058 Select this if you have a 32-bit processor and more than 4
1059 gigabytes of physical RAM.
1064 depends on EXPERIMENTAL
1065 prompt "Memory split" if EMBEDDED
1069 Select the desired split between kernel and user memory.
1071 If the address range available to the kernel is less than the
1072 physical memory installed, the remaining memory will be available
1073 as "high memory". Accessing high memory is a little more costly
1074 than low memory, as it needs to be mapped into the kernel first.
1075 Note that increasing the kernel address space limits the range
1076 available to user programs, making the address space there
1077 tighter. Selecting anything other than the default 3G/1G split
1078 will also likely make your kernel incompatible with binary-only
1081 If you are not absolutely sure what you are doing, leave this
1085 bool "3G/1G user/kernel split"
1086 config VMSPLIT_3G_OPT
1088 bool "3G/1G user/kernel split (for full 1G low memory)"
1090 bool "2G/2G user/kernel split"
1091 config VMSPLIT_2G_OPT
1093 bool "2G/2G user/kernel split (for full 2G low memory)"
1095 bool "1G/3G user/kernel split"
1100 default 0xB0000000 if VMSPLIT_3G_OPT
1101 default 0x80000000 if VMSPLIT_2G
1102 default 0x78000000 if VMSPLIT_2G_OPT
1103 default 0x40000000 if VMSPLIT_1G
1109 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1112 bool "PAE (Physical Address Extension) Support"
1113 depends on X86_32 && !HIGHMEM4G
1115 PAE is required for NX support, and furthermore enables
1116 larger swapspace support for non-overcommit purposes. It
1117 has the cost of more pagetable lookup overhead, and also
1118 consumes more pagetable space per process.
1120 config ARCH_PHYS_ADDR_T_64BIT
1121 def_bool X86_64 || X86_PAE
1123 config DIRECT_GBPAGES
1124 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1128 Allow the kernel linear mapping to use 1GB pages on CPUs that
1129 support it. This can improve the kernel's performance a tiny bit by
1130 reducing TLB pressure. If in doubt, say "Y".
1132 # Common NUMA Features
1134 bool "Numa Memory Allocation and Scheduler Support"
1136 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1137 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1139 Enable NUMA (Non Uniform Memory Access) support.
1141 The kernel will try to allocate memory used by a CPU on the
1142 local memory controller of the CPU and add some more
1143 NUMA awareness to the kernel.
1145 For 64-bit this is recommended if the system is Intel Core i7
1146 (or later), AMD Opteron, or EM64T NUMA.
1148 For 32-bit this is only needed on (rare) 32-bit-only platforms
1149 that support NUMA topologies, such as NUMAQ / Summit, or if you
1150 boot a 32-bit kernel on a 64-bit NUMA platform.
1152 Otherwise, you should say N.
1154 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1155 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1159 prompt "Old style AMD Opteron NUMA detection"
1160 depends on X86_64 && NUMA && PCI
1162 Enable K8 NUMA node topology detection. You should say Y here if
1163 you have a multi processor AMD K8 system. This uses an old
1164 method to read the NUMA configuration directly from the builtin
1165 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1166 instead, which also takes priority if both are compiled in.
1168 config X86_64_ACPI_NUMA
1170 prompt "ACPI NUMA detection"
1171 depends on X86_64 && NUMA && ACPI && PCI
1174 Enable ACPI SRAT based node topology detection.
1176 # Some NUMA nodes have memory ranges that span
1177 # other nodes. Even though a pfn is valid and
1178 # between a node's start and end pfns, it may not
1179 # reside on that node. See memmap_init_zone()
1181 config NODES_SPAN_OTHER_NODES
1183 depends on X86_64_ACPI_NUMA
1186 bool "NUMA emulation"
1187 depends on X86_64 && NUMA
1189 Enable NUMA emulation. A flat machine will be split
1190 into virtual nodes when booted with "numa=fake=N", where N is the
1191 number of nodes. This is only useful for debugging.
1194 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1196 default "9" if MAXSMP
1197 default "6" if X86_64
1198 default "4" if X86_NUMAQ
1200 depends on NEED_MULTIPLE_NODES
1202 Specify the maximum number of NUMA Nodes available on the target
1203 system. Increases memory reserved to accommodate various tables.
1205 config HAVE_ARCH_BOOTMEM
1207 depends on X86_32 && NUMA
1209 config ARCH_HAVE_MEMORY_PRESENT
1211 depends on X86_32 && DISCONTIGMEM
1213 config NEED_NODE_MEMMAP_SIZE
1215 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1217 config HAVE_ARCH_ALLOC_REMAP
1219 depends on X86_32 && NUMA
1221 config ARCH_FLATMEM_ENABLE
1223 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1225 config ARCH_DISCONTIGMEM_ENABLE
1227 depends on NUMA && X86_32
1229 config ARCH_DISCONTIGMEM_DEFAULT
1231 depends on NUMA && X86_32
1233 config ARCH_SPARSEMEM_DEFAULT
1237 config ARCH_SPARSEMEM_ENABLE
1239 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1240 select SPARSEMEM_STATIC if X86_32
1241 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1243 config ARCH_SELECT_MEMORY_MODEL
1245 depends on ARCH_SPARSEMEM_ENABLE
1247 config ARCH_MEMORY_PROBE
1249 depends on MEMORY_HOTPLUG
1254 bool "Allocate 3rd-level pagetables from highmem"
1255 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1257 The VM uses one page table entry for each page of physical memory.
1258 For systems with a lot of RAM, this can be wasteful of precious
1259 low memory. Setting this option will put user-space page table
1260 entries in high memory.
1262 config X86_CHECK_BIOS_CORRUPTION
1263 bool "Check for low memory corruption"
1265 Periodically check for memory corruption in low memory, which
1266 is suspected to be caused by BIOS. Even when enabled in the
1267 configuration, it is disabled at runtime. Enable it by
1268 setting "memory_corruption_check=1" on the kernel command
1269 line. By default it scans the low 64k of memory every 60
1270 seconds; see the memory_corruption_check_size and
1271 memory_corruption_check_period parameters in
1272 Documentation/kernel-parameters.txt to adjust this.
1274 When enabled with the default parameters, this option has
1275 almost no overhead, as it reserves a relatively small amount
1276 of memory and scans it infrequently. It both detects corruption
1277 and prevents it from affecting the running system.
1279 It is, however, intended as a diagnostic tool; if repeatable
1280 BIOS-originated corruption always affects the same memory,
1281 you can use memmap= to prevent the kernel from using that
1284 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1285 bool "Set the default setting of memory_corruption_check"
1286 depends on X86_CHECK_BIOS_CORRUPTION
1289 Set whether the default state of memory_corruption_check is
1292 config X86_RESERVE_LOW_64K
1293 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1296 Reserve the first 64K of physical RAM on BIOSes that are known
1297 to potentially corrupt that memory range. A numbers of BIOSes are
1298 known to utilize this area during suspend/resume, so it must not
1299 be used by the kernel.
1301 Set this to N if you are absolutely sure that you trust the BIOS
1302 to get all its memory reservations and usages right.
1304 If you have doubts about the BIOS (e.g. suspend/resume does not
1305 work or there's kernel crashes after certain hardware hotplug
1306 events) and it's not AMI or Phoenix, then you might want to enable
1307 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1308 corruption patterns.
1312 config MATH_EMULATION
1314 prompt "Math emulation" if X86_32
1316 Linux can emulate a math coprocessor (used for floating point
1317 operations) if you don't have one. 486DX and Pentium processors have
1318 a math coprocessor built in, 486SX and 386 do not, unless you added
1319 a 487DX or 387, respectively. (The messages during boot time can
1320 give you some hints here ["man dmesg"].) Everyone needs either a
1321 coprocessor or this emulation.
1323 If you don't have a math coprocessor, you need to say Y here; if you
1324 say Y here even though you have a coprocessor, the coprocessor will
1325 be used nevertheless. (This behavior can be changed with the kernel
1326 command line option "no387", which comes handy if your coprocessor
1327 is broken. Try "man bootparam" or see the documentation of your boot
1328 loader (lilo or loadlin) about how to pass options to the kernel at
1329 boot time.) This means that it is a good idea to say Y here if you
1330 intend to use this kernel on different machines.
1332 More information about the internals of the Linux math coprocessor
1333 emulation can be found in <file:arch/x86/math-emu/README>.
1335 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1336 kernel, it won't hurt.
1339 bool "MTRR (Memory Type Range Register) support"
1341 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1342 the Memory Type Range Registers (MTRRs) may be used to control
1343 processor access to memory ranges. This is most useful if you have
1344 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1345 allows bus write transfers to be combined into a larger transfer
1346 before bursting over the PCI/AGP bus. This can increase performance
1347 of image write operations 2.5 times or more. Saying Y here creates a
1348 /proc/mtrr file which may be used to manipulate your processor's
1349 MTRRs. Typically the X server should use this.
1351 This code has a reasonably generic interface so that similar
1352 control registers on other processors can be easily supported
1355 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1356 Registers (ARRs) which provide a similar functionality to MTRRs. For
1357 these, the ARRs are used to emulate the MTRRs.
1358 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1359 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1360 write-combining. All of these processors are supported by this code
1361 and it makes sense to say Y here if you have one of them.
1363 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1364 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1365 can lead to all sorts of problems, so it's good to say Y here.
1367 You can safely say Y even if your machine doesn't have MTRRs, you'll
1368 just add about 9 KB to your kernel.
1370 See <file:Documentation/x86/mtrr.txt> for more information.
1372 config MTRR_SANITIZER
1374 prompt "MTRR cleanup support"
1377 Convert MTRR layout from continuous to discrete, so X drivers can
1378 add writeback entries.
1380 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1381 The largest mtrr entry size for a continuous block can be set with
1386 config MTRR_SANITIZER_ENABLE_DEFAULT
1387 int "MTRR cleanup enable value (0-1)"
1390 depends on MTRR_SANITIZER
1392 Enable mtrr cleanup default value
1394 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1395 int "MTRR cleanup spare reg num (0-7)"
1398 depends on MTRR_SANITIZER
1400 mtrr cleanup spare entries default, it can be changed via
1401 mtrr_spare_reg_nr=N on the kernel command line.
1405 prompt "x86 PAT support"
1408 Use PAT attributes to setup page level cache control.
1410 PATs are the modern equivalents of MTRRs and are much more
1411 flexible than MTRRs.
1413 Say N here if you see bootup problems (boot crash, boot hang,
1414 spontaneous reboots) or a non-working video driver.
1419 bool "EFI runtime service support"
1422 This enables the kernel to use EFI runtime services that are
1423 available (such as the EFI variable services).
1425 This option is only useful on systems that have EFI firmware.
1426 In addition, you should use the latest ELILO loader available
1427 at <http://elilo.sourceforge.net> in order to take advantage
1428 of EFI runtime services. However, even with this option, the
1429 resultant kernel should continue to boot on existing non-EFI
1434 prompt "Enable seccomp to safely compute untrusted bytecode"
1436 This kernel feature is useful for number crunching applications
1437 that may need to compute untrusted bytecode during their
1438 execution. By using pipes or other transports made available to
1439 the process as file descriptors supporting the read/write
1440 syscalls, it's possible to isolate those applications in
1441 their own address space using seccomp. Once seccomp is
1442 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1443 and the task is only allowed to execute a few safe syscalls
1444 defined by each seccomp mode.
1446 If unsure, say Y. Only embedded should say N here.
1448 config CC_STACKPROTECTOR_ALL
1451 config CC_STACKPROTECTOR
1452 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1453 select CC_STACKPROTECTOR_ALL
1455 This option turns on the -fstack-protector GCC feature. This
1456 feature puts, at the beginning of functions, a canary value on
1457 the stack just before the return address, and validates
1458 the value just before actually returning. Stack based buffer
1459 overflows (that need to overwrite this return address) now also
1460 overwrite the canary, which gets detected and the attack is then
1461 neutralized via a kernel panic.
1463 This feature requires gcc version 4.2 or above, or a distribution
1464 gcc with the feature backported. Older versions are automatically
1465 detected and for those versions, this configuration option is
1466 ignored. (and a warning is printed during bootup)
1468 source kernel/Kconfig.hz
1471 bool "kexec system call"
1473 kexec is a system call that implements the ability to shutdown your
1474 current kernel, and to start another kernel. It is like a reboot
1475 but it is independent of the system firmware. And like a reboot
1476 you can start any kernel with it, not just Linux.
1478 The name comes from the similarity to the exec system call.
1480 It is an ongoing process to be certain the hardware in a machine
1481 is properly shutdown, so do not be surprised if this code does not
1482 initially work for you. It may help to enable device hotplugging
1483 support. As of this writing the exact hardware interface is
1484 strongly in flux, so no good recommendation can be made.
1487 bool "kernel crash dumps"
1488 depends on X86_64 || (X86_32 && HIGHMEM)
1490 Generate crash dump after being started by kexec.
1491 This should be normally only set in special crash dump kernels
1492 which are loaded in the main kernel with kexec-tools into
1493 a specially reserved region and then later executed after
1494 a crash by kdump/kexec. The crash dump kernel must be compiled
1495 to a memory address not used by the main kernel or BIOS using
1496 PHYSICAL_START, or it must be built as a relocatable image
1497 (CONFIG_RELOCATABLE=y).
1498 For more details see Documentation/kdump/kdump.txt
1501 bool "kexec jump (EXPERIMENTAL)"
1502 depends on EXPERIMENTAL
1503 depends on KEXEC && HIBERNATION
1505 Jump between original kernel and kexeced kernel and invoke
1506 code in physical address mode via KEXEC
1508 config PHYSICAL_START
1509 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1512 This gives the physical address where the kernel is loaded.
1514 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1515 bzImage will decompress itself to above physical address and
1516 run from there. Otherwise, bzImage will run from the address where
1517 it has been loaded by the boot loader and will ignore above physical
1520 In normal kdump cases one does not have to set/change this option
1521 as now bzImage can be compiled as a completely relocatable image
1522 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1523 address. This option is mainly useful for the folks who don't want
1524 to use a bzImage for capturing the crash dump and want to use a
1525 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1526 to be specifically compiled to run from a specific memory area
1527 (normally a reserved region) and this option comes handy.
1529 So if you are using bzImage for capturing the crash dump,
1530 leave the value here unchanged to 0x1000000 and set
1531 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1532 for capturing the crash dump change this value to start of
1533 the reserved region. In other words, it can be set based on
1534 the "X" value as specified in the "crashkernel=YM@XM"
1535 command line boot parameter passed to the panic-ed
1536 kernel. Please take a look at Documentation/kdump/kdump.txt
1537 for more details about crash dumps.
1539 Usage of bzImage for capturing the crash dump is recommended as
1540 one does not have to build two kernels. Same kernel can be used
1541 as production kernel and capture kernel. Above option should have
1542 gone away after relocatable bzImage support is introduced. But it
1543 is present because there are users out there who continue to use
1544 vmlinux for dump capture. This option should go away down the
1547 Don't change this unless you know what you are doing.
1550 bool "Build a relocatable kernel"
1553 This builds a kernel image that retains relocation information
1554 so it can be loaded someplace besides the default 1MB.
1555 The relocations tend to make the kernel binary about 10% larger,
1556 but are discarded at runtime.
1558 One use is for the kexec on panic case where the recovery kernel
1559 must live at a different physical address than the primary
1562 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1563 it has been loaded at and the compile time physical address
1564 (CONFIG_PHYSICAL_START) is ignored.
1566 # Relocation on x86-32 needs some additional build support
1567 config X86_NEED_RELOCS
1569 depends on X86_32 && RELOCATABLE
1571 config PHYSICAL_ALIGN
1573 prompt "Alignment value to which kernel should be aligned" if X86_32
1575 range 0x2000 0x1000000
1577 This value puts the alignment restrictions on physical address
1578 where kernel is loaded and run from. Kernel is compiled for an
1579 address which meets above alignment restriction.
1581 If bootloader loads the kernel at a non-aligned address and
1582 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1583 address aligned to above value and run from there.
1585 If bootloader loads the kernel at a non-aligned address and
1586 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1587 load address and decompress itself to the address it has been
1588 compiled for and run from there. The address for which kernel is
1589 compiled already meets above alignment restrictions. Hence the
1590 end result is that kernel runs from a physical address meeting
1591 above alignment restrictions.
1593 Don't change this unless you know what you are doing.
1596 bool "Support for hot-pluggable CPUs"
1597 depends on SMP && HOTPLUG
1599 Say Y here to allow turning CPUs off and on. CPUs can be
1600 controlled through /sys/devices/system/cpu.
1601 ( Note: power management support will enable this option
1602 automatically on SMP systems. )
1603 Say N if you want to disable CPU hotplug.
1607 prompt "Compat VDSO support"
1608 depends on X86_32 || IA32_EMULATION
1610 Map the 32-bit VDSO to the predictable old-style address too.
1612 Say N here if you are running a sufficiently recent glibc
1613 version (2.3.3 or later), to remove the high-mapped
1614 VDSO mapping and to exclusively use the randomized VDSO.
1619 bool "Built-in kernel command line"
1622 Allow for specifying boot arguments to the kernel at
1623 build time. On some systems (e.g. embedded ones), it is
1624 necessary or convenient to provide some or all of the
1625 kernel boot arguments with the kernel itself (that is,
1626 to not rely on the boot loader to provide them.)
1628 To compile command line arguments into the kernel,
1629 set this option to 'Y', then fill in the
1630 the boot arguments in CONFIG_CMDLINE.
1632 Systems with fully functional boot loaders (i.e. non-embedded)
1633 should leave this option set to 'N'.
1636 string "Built-in kernel command string"
1637 depends on CMDLINE_BOOL
1640 Enter arguments here that should be compiled into the kernel
1641 image and used at boot time. If the boot loader provides a
1642 command line at boot time, it is appended to this string to
1643 form the full kernel command line, when the system boots.
1645 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1646 change this behavior.
1648 In most cases, the command line (whether built-in or provided
1649 by the boot loader) should specify the device for the root
1652 config CMDLINE_OVERRIDE
1653 bool "Built-in command line overrides boot loader arguments"
1655 depends on CMDLINE_BOOL
1657 Set this option to 'Y' to have the kernel ignore the boot loader
1658 command line, and use ONLY the built-in command line.
1660 This is used to work around broken boot loaders. This should
1661 be set to 'N' under normal conditions.
1665 config ARCH_ENABLE_MEMORY_HOTPLUG
1667 depends on X86_64 || (X86_32 && HIGHMEM)
1669 config ARCH_ENABLE_MEMORY_HOTREMOVE
1671 depends on MEMORY_HOTPLUG
1673 config HAVE_ARCH_EARLY_PFN_TO_NID
1677 menu "Power management and ACPI options"
1679 config ARCH_HIBERNATION_HEADER
1681 depends on X86_64 && HIBERNATION
1683 source "kernel/power/Kconfig"
1685 source "drivers/acpi/Kconfig"
1690 depends on APM || APM_MODULE
1693 tristate "APM (Advanced Power Management) BIOS support"
1694 depends on X86_32 && PM_SLEEP
1696 APM is a BIOS specification for saving power using several different
1697 techniques. This is mostly useful for battery powered laptops with
1698 APM compliant BIOSes. If you say Y here, the system time will be
1699 reset after a RESUME operation, the /proc/apm device will provide
1700 battery status information, and user-space programs will receive
1701 notification of APM "events" (e.g. battery status change).
1703 If you select "Y" here, you can disable actual use of the APM
1704 BIOS by passing the "apm=off" option to the kernel at boot time.
1706 Note that the APM support is almost completely disabled for
1707 machines with more than one CPU.
1709 In order to use APM, you will need supporting software. For location
1710 and more information, read <file:Documentation/power/pm.txt> and the
1711 Battery Powered Linux mini-HOWTO, available from
1712 <http://www.tldp.org/docs.html#howto>.
1714 This driver does not spin down disk drives (see the hdparm(8)
1715 manpage ("man 8 hdparm") for that), and it doesn't turn off
1716 VESA-compliant "green" monitors.
1718 This driver does not support the TI 4000M TravelMate and the ACER
1719 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1720 desktop machines also don't have compliant BIOSes, and this driver
1721 may cause those machines to panic during the boot phase.
1723 Generally, if you don't have a battery in your machine, there isn't
1724 much point in using this driver and you should say N. If you get
1725 random kernel OOPSes or reboots that don't seem to be related to
1726 anything, try disabling/enabling this option (or disabling/enabling
1729 Some other things you should try when experiencing seemingly random,
1732 1) make sure that you have enough swap space and that it is
1734 2) pass the "no-hlt" option to the kernel
1735 3) switch on floating point emulation in the kernel and pass
1736 the "no387" option to the kernel
1737 4) pass the "floppy=nodma" option to the kernel
1738 5) pass the "mem=4M" option to the kernel (thereby disabling
1739 all but the first 4 MB of RAM)
1740 6) make sure that the CPU is not over clocked.
1741 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1742 8) disable the cache from your BIOS settings
1743 9) install a fan for the video card or exchange video RAM
1744 10) install a better fan for the CPU
1745 11) exchange RAM chips
1746 12) exchange the motherboard.
1748 To compile this driver as a module, choose M here: the
1749 module will be called apm.
1753 config APM_IGNORE_USER_SUSPEND
1754 bool "Ignore USER SUSPEND"
1756 This option will ignore USER SUSPEND requests. On machines with a
1757 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1758 series notebooks, it is necessary to say Y because of a BIOS bug.
1760 config APM_DO_ENABLE
1761 bool "Enable PM at boot time"
1763 Enable APM features at boot time. From page 36 of the APM BIOS
1764 specification: "When disabled, the APM BIOS does not automatically
1765 power manage devices, enter the Standby State, enter the Suspend
1766 State, or take power saving steps in response to CPU Idle calls."
1767 This driver will make CPU Idle calls when Linux is idle (unless this
1768 feature is turned off -- see "Do CPU IDLE calls", below). This
1769 should always save battery power, but more complicated APM features
1770 will be dependent on your BIOS implementation. You may need to turn
1771 this option off if your computer hangs at boot time when using APM
1772 support, or if it beeps continuously instead of suspending. Turn
1773 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1774 T400CDT. This is off by default since most machines do fine without
1778 bool "Make CPU Idle calls when idle"
1780 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1781 On some machines, this can activate improved power savings, such as
1782 a slowed CPU clock rate, when the machine is idle. These idle calls
1783 are made after the idle loop has run for some length of time (e.g.,
1784 333 mS). On some machines, this will cause a hang at boot time or
1785 whenever the CPU becomes idle. (On machines with more than one CPU,
1786 this option does nothing.)
1788 config APM_DISPLAY_BLANK
1789 bool "Enable console blanking using APM"
1791 Enable console blanking using the APM. Some laptops can use this to
1792 turn off the LCD backlight when the screen blanker of the Linux
1793 virtual console blanks the screen. Note that this is only used by
1794 the virtual console screen blanker, and won't turn off the backlight
1795 when using the X Window system. This also doesn't have anything to
1796 do with your VESA-compliant power-saving monitor. Further, this
1797 option doesn't work for all laptops -- it might not turn off your
1798 backlight at all, or it might print a lot of errors to the console,
1799 especially if you are using gpm.
1801 config APM_ALLOW_INTS
1802 bool "Allow interrupts during APM BIOS calls"
1804 Normally we disable external interrupts while we are making calls to
1805 the APM BIOS as a measure to lessen the effects of a badly behaving
1806 BIOS implementation. The BIOS should reenable interrupts if it
1807 needs to. Unfortunately, some BIOSes do not -- especially those in
1808 many of the newer IBM Thinkpads. If you experience hangs when you
1809 suspend, try setting this to Y. Otherwise, say N.
1813 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1815 source "drivers/cpuidle/Kconfig"
1817 source "drivers/idle/Kconfig"
1822 menu "Bus options (PCI etc.)"
1827 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1829 Find out whether you have a PCI motherboard. PCI is the name of a
1830 bus system, i.e. the way the CPU talks to the other stuff inside
1831 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1832 VESA. If you have PCI, say Y, otherwise N.
1835 prompt "PCI access mode"
1836 depends on X86_32 && PCI
1839 On PCI systems, the BIOS can be used to detect the PCI devices and
1840 determine their configuration. However, some old PCI motherboards
1841 have BIOS bugs and may crash if this is done. Also, some embedded
1842 PCI-based systems don't have any BIOS at all. Linux can also try to
1843 detect the PCI hardware directly without using the BIOS.
1845 With this option, you can specify how Linux should detect the
1846 PCI devices. If you choose "BIOS", the BIOS will be used,
1847 if you choose "Direct", the BIOS won't be used, and if you
1848 choose "MMConfig", then PCI Express MMCONFIG will be used.
1849 If you choose "Any", the kernel will try MMCONFIG, then the
1850 direct access method and falls back to the BIOS if that doesn't
1851 work. If unsure, go with the default, which is "Any".
1856 config PCI_GOMMCONFIG
1873 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1875 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1878 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1882 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1886 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1893 bool "Support mmconfig PCI config space access"
1894 depends on X86_64 && PCI && ACPI
1897 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1898 depends on PCI_MSI && ACPI && EXPERIMENTAL
1900 DMA remapping (DMAR) devices support enables independent address
1901 translations for Direct Memory Access (DMA) from devices.
1902 These DMA remapping devices are reported via ACPI tables
1903 and include PCI device scope covered by these DMA
1906 config DMAR_DEFAULT_ON
1908 prompt "Enable DMA Remapping Devices by default"
1911 Selecting this option will enable a DMAR device at boot time if
1912 one is found. If this option is not selected, DMAR support can
1913 be enabled by passing intel_iommu=on to the kernel. It is
1914 recommended you say N here while the DMAR code remains
1917 config DMAR_BROKEN_GFX_WA
1919 prompt "Workaround broken graphics drivers (going away soon)"
1922 Current Graphics drivers tend to use physical address
1923 for DMA and avoid using DMA APIs. Setting this config
1924 option permits the IOMMU driver to set a unity map for
1925 all the OS-visible memory. Hence the driver can continue
1926 to use physical addresses for DMA, at least until this
1927 option is removed in the 2.6.32 kernel.
1929 config DMAR_FLOPPY_WA
1933 Floppy disk drivers are known to bypass DMA API calls
1934 thereby failing to work when IOMMU is enabled. This
1935 workaround will setup a 1:1 mapping for the first
1936 16MiB to make floppy (an ISA device) work.
1939 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1940 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1942 Supports Interrupt remapping for IO-APIC and MSI devices.
1943 To use x2apic mode in the CPU's which support x2APIC enhancements or
1944 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1946 source "drivers/pci/pcie/Kconfig"
1948 source "drivers/pci/Kconfig"
1950 # x86_64 have no ISA slots, but do have ISA-style DMA.
1959 Find out whether you have ISA slots on your motherboard. ISA is the
1960 name of a bus system, i.e. the way the CPU talks to the other stuff
1961 inside your box. Other bus systems are PCI, EISA, MicroChannel
1962 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1963 newer boards don't support it. If you have ISA, say Y, otherwise N.
1969 The Extended Industry Standard Architecture (EISA) bus was
1970 developed as an open alternative to the IBM MicroChannel bus.
1972 The EISA bus provided some of the features of the IBM MicroChannel
1973 bus while maintaining backward compatibility with cards made for
1974 the older ISA bus. The EISA bus saw limited use between 1988 and
1975 1995 when it was made obsolete by the PCI bus.
1977 Say Y here if you are building a kernel for an EISA-based machine.
1981 source "drivers/eisa/Kconfig"
1986 MicroChannel Architecture is found in some IBM PS/2 machines and
1987 laptops. It is a bus system similar to PCI or ISA. See
1988 <file:Documentation/mca.txt> (and especially the web page given
1989 there) before attempting to build an MCA bus kernel.
1991 source "drivers/mca/Kconfig"
1994 tristate "NatSemi SCx200 support"
1996 This provides basic support for National Semiconductor's
1997 (now AMD's) Geode processors. The driver probes for the
1998 PCI-IDs of several on-chip devices, so its a good dependency
1999 for other scx200_* drivers.
2001 If compiled as a module, the driver is named scx200.
2003 config SCx200HR_TIMER
2004 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2005 depends on SCx200 && GENERIC_TIME
2008 This driver provides a clocksource built upon the on-chip
2009 27MHz high-resolution timer. Its also a workaround for
2010 NSC Geode SC-1100's buggy TSC, which loses time when the
2011 processor goes idle (as is done by the scheduler). The
2012 other workaround is idle=poll boot option.
2014 config GEODE_MFGPT_TIMER
2016 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2017 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2019 This driver provides a clock event source based on the MFGPT
2020 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2021 MFGPTs have a better resolution and max interval than the
2022 generic PIT, and are suitable for use as high-res timers.
2025 bool "One Laptop Per Child support"
2028 Add support for detecting the unique features of the OLPC
2035 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2037 source "drivers/pcmcia/Kconfig"
2039 source "drivers/pci/hotplug/Kconfig"
2044 menu "Executable file formats / Emulations"
2046 source "fs/Kconfig.binfmt"
2048 config IA32_EMULATION
2049 bool "IA32 Emulation"
2051 select COMPAT_BINFMT_ELF
2053 Include code to run 32-bit programs under a 64-bit kernel. You should
2054 likely turn this on, unless you're 100% sure that you don't have any
2055 32-bit programs left.
2058 tristate "IA32 a.out support"
2059 depends on IA32_EMULATION
2061 Support old a.out binaries in the 32bit emulation.
2065 depends on IA32_EMULATION
2067 config COMPAT_FOR_U64_ALIGNMENT
2071 config SYSVIPC_COMPAT
2073 depends on COMPAT && SYSVIPC
2078 config HAVE_ATOMIC_IOMAP
2082 source "net/Kconfig"
2084 source "drivers/Kconfig"
2086 source "drivers/firmware/Kconfig"
2090 source "arch/x86/Kconfig.debug"
2092 source "security/Kconfig"
2094 source "crypto/Kconfig"
2096 source "arch/x86/kvm/Kconfig"
2098 source "lib/Kconfig"