2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_FTRACE_SYSCALLS
41 select HAVE_ARCH_TRACEHOOK
42 select HAVE_GENERIC_DMA_COHERENT if X86_32
43 select HAVE_EFFICIENT_UNALIGNED_ACCESS
44 select USER_STACKTRACE_SUPPORT
45 select HAVE_DMA_API_DEBUG
46 select HAVE_KERNEL_GZIP
47 select HAVE_KERNEL_BZIP2
48 select HAVE_KERNEL_LZMA
49 select HAVE_ARCH_KMEMCHECK
53 default "elf32-i386" if X86_32
54 default "elf64-x86-64" if X86_64
58 default "arch/x86/configs/i386_defconfig" if X86_32
59 default "arch/x86/configs/x86_64_defconfig" if X86_64
64 config GENERIC_CMOS_UPDATE
67 config CLOCKSOURCE_WATCHDOG
70 config GENERIC_CLOCKEVENTS
73 config GENERIC_CLOCKEVENTS_BROADCAST
75 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
77 config LOCKDEP_SUPPORT
80 config STACKTRACE_SUPPORT
83 config HAVE_LATENCYTOP_SUPPORT
86 config FAST_CMPXCHG_LOCAL
99 config GENERIC_ISA_DMA
108 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
110 config GENERIC_BUG_RELATIVE_POINTERS
113 config GENERIC_HWEIGHT
119 config ARCH_MAY_HAVE_PC_FDC
122 config RWSEM_GENERIC_SPINLOCK
125 config RWSEM_XCHGADD_ALGORITHM
128 config ARCH_HAS_CPU_IDLE_WAIT
131 config GENERIC_CALIBRATE_DELAY
134 config GENERIC_TIME_VSYSCALL
138 config ARCH_HAS_CPU_RELAX
141 config ARCH_HAS_DEFAULT_IDLE
144 config ARCH_HAS_CACHE_LINE_SIZE
147 config HAVE_SETUP_PER_CPU_AREA
150 config HAVE_DYNAMIC_PER_CPU_AREA
153 config HAVE_CPUMASK_OF_CPU_MAP
156 config ARCH_HIBERNATION_POSSIBLE
159 config ARCH_SUSPEND_POSSIBLE
166 config ARCH_POPULATES_NODE_MAP
173 config ARCH_SUPPORTS_OPTIMIZED_INLINING
176 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
179 # Use the generic interrupt handling code in kernel/irq/:
180 config GENERIC_HARDIRQS
184 config GENERIC_HARDIRQS_NO__DO_IRQ
187 config GENERIC_IRQ_PROBE
191 config GENERIC_PENDING_IRQ
193 depends on GENERIC_HARDIRQS && SMP
196 config USE_GENERIC_SMP_HELPERS
202 depends on X86_32 && SMP
206 depends on X86_64 && SMP
213 config X86_TRAMPOLINE
215 depends on SMP || (64BIT && ACPI_SLEEP)
218 config X86_32_LAZY_GS
220 depends on X86_32 && !CC_STACKPROTECTOR
224 source "init/Kconfig"
225 source "kernel/Kconfig.freezer"
227 menu "Processor type and features"
229 source "kernel/time/Kconfig"
232 bool "Symmetric multi-processing support"
234 This enables support for systems with more than one CPU. If you have
235 a system with only one CPU, like most personal computers, say N. If
236 you have a system with more than one CPU, say Y.
238 If you say N here, the kernel will run on single and multiprocessor
239 machines, but will use only one CPU of a multiprocessor machine. If
240 you say Y here, the kernel will run on many, but not all,
241 singleprocessor machines. On a singleprocessor machine, the kernel
242 will run faster if you say N here.
244 Note that if you say Y here and choose architecture "586" or
245 "Pentium" under "Processor family", the kernel will not work on 486
246 architectures. Similarly, multiprocessor kernels for the "PPro"
247 architecture may not work on all Pentium based boards.
249 People using multiprocessor machines who say Y here should also say
250 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
251 Management" code will be disabled if you say Y here.
253 See also <file:Documentation/i386/IO-APIC.txt>,
254 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
255 <http://www.tldp.org/docs.html#howto>.
257 If you don't know what to do here, say N.
260 bool "Support x2apic"
261 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
263 This enables x2apic support on CPUs that have this feature.
265 This allows 32-bit apic IDs (so it can support very large systems),
266 and accesses the local apic via MSRs not via mmio.
268 If you don't know what to do here, say N.
271 bool "Support sparse irq numbering"
272 depends on PCI_MSI || HT_IRQ
274 This enables support for sparse irqs. This is useful for distro
275 kernels that want to define a high CONFIG_NR_CPUS value but still
276 want to have low kernel memory footprint on smaller machines.
278 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
279 out the irq_desc[] array in a more NUMA-friendly way. )
281 If you don't know what to do here, say N.
285 depends on SPARSE_IRQ && NUMA
288 bool "Enable MPS table" if ACPI
290 depends on X86_LOCAL_APIC
292 For old smp systems that do not have proper acpi support. Newer systems
293 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
296 bool "Support for big SMP systems with more than 8 CPUs"
297 depends on X86_32 && SMP
299 This option is needed for the systems that have more than 8 CPUs
302 config X86_EXTENDED_PLATFORM
303 bool "Support for extended (non-PC) x86 platforms"
306 If you disable this option then the kernel will only support
307 standard PC platforms. (which covers the vast majority of
310 If you enable this option then you'll be able to select support
311 for the following (non-PC) 32 bit x86 platforms:
315 SGI 320/540 (Visual Workstation)
316 Summit/EXA (IBM x440)
317 Unisys ES7000 IA32 series
319 If you have one of these systems, or if you want to build a
320 generic distribution kernel, say Y here - otherwise say N.
324 config X86_EXTENDED_PLATFORM
325 bool "Support for extended (non-PC) x86 platforms"
328 If you disable this option then the kernel will only support
329 standard PC platforms. (which covers the vast majority of
332 If you enable this option then you'll be able to select support
333 for the following (non-PC) 64 bit x86 platforms:
337 If you have one of these systems, or if you want to build a
338 generic distribution kernel, say Y here - otherwise say N.
340 # This is an alphabetically sorted list of 64 bit extended platforms
341 # Please maintain the alphabetic order if and when there are additions
346 depends on X86_64 && PCI
347 depends on X86_EXTENDED_PLATFORM
349 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
350 supposed to run on these EM64T-based machines. Only choose this option
351 if you have one of these machines.
354 bool "SGI Ultraviolet"
356 depends on X86_EXTENDED_PLATFORM
358 depends on X86_X2APIC
360 This option is needed in order to support SGI Ultraviolet systems.
361 If you don't have one of these, you should say N here.
363 # Following is an alphabetically sorted list of 32 bit extended platforms
364 # Please maintain the alphabetic order if and when there are additions
369 depends on X86_EXTENDED_PLATFORM
371 Select this for an AMD Elan processor.
373 Do not use this option for K6/Athlon/Opteron processors!
375 If unsure, choose "PC-compatible" instead.
378 bool "RDC R-321x SoC"
380 depends on X86_EXTENDED_PLATFORM
382 select X86_REBOOTFIXUPS
384 This option is needed for RDC R-321x system-on-chip, also known
386 If you don't have one of these chips, you should say N here.
388 config X86_32_NON_STANDARD
389 bool "Support non-standard 32-bit SMP architectures"
390 depends on X86_32 && SMP
391 depends on X86_EXTENDED_PLATFORM
393 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
394 subarchitectures. It is intended for a generic binary kernel.
395 if you select them all, kernel will probe it one by one. and will
398 # Alphabetically sorted list of Non standard 32 bit platforms
401 bool "NUMAQ (IBM/Sequent)"
402 depends on X86_32_NON_STANDARD
406 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
407 NUMA multiquad box. This changes the way that processors are
408 bootstrapped, and uses Clustered Logical APIC addressing mode instead
409 of Flat Logical. You will need a new lynxer.elf file to flash your
410 firmware with - send email to <Martin.Bligh@us.ibm.com>.
413 bool "SGI 320/540 (Visual Workstation)"
414 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
415 depends on X86_32_NON_STANDARD
417 The SGI Visual Workstation series is an IA32-based workstation
418 based on SGI systems chips with some legacy PC hardware attached.
420 Say Y here to create a kernel to run on the SGI 320 or 540.
422 A kernel compiled for the Visual Workstation will run on general
423 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
426 bool "Summit/EXA (IBM x440)"
427 depends on X86_32_NON_STANDARD
429 This option is needed for IBM systems that use the Summit/EXA chipset.
430 In particular, it is needed for the x440.
433 bool "Unisys ES7000 IA32 series"
434 depends on X86_32_NON_STANDARD && X86_BIGSMP
436 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
437 supposed to run on an IA32-based Unisys ES7000 system.
439 config SCHED_OMIT_FRAME_POINTER
441 prompt "Single-depth WCHAN output"
444 Calculate simpler /proc/<PID>/wchan values. If this option
445 is disabled then wchan values will recurse back to the
446 caller function. This provides more accurate wchan values,
447 at the expense of slightly more scheduling overhead.
449 If in doubt, say "Y".
451 menuconfig PARAVIRT_GUEST
452 bool "Paravirtualized guest support"
454 Say Y here to get to see options related to running Linux under
455 various hypervisors. This option alone does not add any kernel code.
457 If you say N, all options in this submenu will be skipped and disabled.
461 source "arch/x86/xen/Kconfig"
464 bool "VMI Guest support"
468 VMI provides a paravirtualized interface to the VMware ESX server
469 (it could be used by other hypervisors in theory too, but is not
470 at the moment), by linking the kernel to a GPL-ed ROM module
471 provided by the hypervisor.
474 bool "KVM paravirtualized clock"
476 select PARAVIRT_CLOCK
478 Turning on this option will allow you to run a paravirtualized clock
479 when running over the KVM hypervisor. Instead of relying on a PIT
480 (or probably other) emulation by the underlying device model, the host
481 provides the guest with timing infrastructure such as time of day, and
485 bool "KVM Guest support"
488 This option enables various optimizations for running under the KVM
491 source "arch/x86/lguest/Kconfig"
494 bool "Enable paravirtualization code"
496 This changes the kernel so it can modify itself when it is run
497 under a hypervisor, potentially improving performance significantly
498 over full virtualization. However, when run without a hypervisor
499 the kernel is theoretically slower and slightly larger.
501 config PARAVIRT_SPINLOCKS
502 bool "Paravirtualization layer for spinlocks"
503 depends on PARAVIRT && SMP && EXPERIMENTAL
505 Paravirtualized spinlocks allow a pvops backend to replace the
506 spinlock implementation with something virtualization-friendly
507 (for example, block the virtual CPU rather than spinning).
509 Unfortunately the downside is an up to 5% performance hit on
510 native kernels, with various workloads.
512 If you are unsure how to answer this question, answer N.
514 config PARAVIRT_CLOCK
520 config PARAVIRT_DEBUG
521 bool "paravirt-ops debugging"
522 depends on PARAVIRT && DEBUG_KERNEL
524 Enable to debug paravirt_ops internals. Specifically, BUG if
525 a paravirt_op is missing when it is called.
530 This option adds a kernel parameter 'memtest', which allows memtest
532 memtest=0, mean disabled; -- default
533 memtest=1, mean do 1 test pattern;
535 memtest=4, mean do 4 test patterns.
536 If you are unsure how to answer this question, answer N.
538 config X86_SUMMIT_NUMA
540 depends on X86_32 && NUMA && X86_32_NON_STANDARD
542 config X86_CYCLONE_TIMER
544 depends on X86_32_NON_STANDARD
546 source "arch/x86/Kconfig.cpu"
550 prompt "HPET Timer Support" if X86_32
552 Use the IA-PC HPET (High Precision Event Timer) to manage
553 time in preference to the PIT and RTC, if a HPET is
555 HPET is the next generation timer replacing legacy 8254s.
556 The HPET provides a stable time base on SMP
557 systems, unlike the TSC, but it is more expensive to access,
558 as it is off-chip. You can find the HPET spec at
559 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
561 You can safely choose Y here. However, HPET will only be
562 activated if the platform and the BIOS support this feature.
563 Otherwise the 8254 will be used for timing services.
565 Choose N to continue using the legacy 8254 timer.
567 config HPET_EMULATE_RTC
569 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
571 # Mark as embedded because too many people got it wrong.
572 # The code disables itself when not needed.
575 bool "Enable DMI scanning" if EMBEDDED
577 Enabled scanning of DMI to identify machine quirks. Say Y
578 here unless you have verified that your setup is not
579 affected by entries in the DMI blacklist. Required by PNP
583 bool "GART IOMMU support" if EMBEDDED
587 depends on X86_64 && PCI
589 Support for full DMA access of devices with 32bit memory access only
590 on systems with more than 3GB. This is usually needed for USB,
591 sound, many IDE/SATA chipsets and some other devices.
592 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
593 based hardware IOMMU and a software bounce buffer based IOMMU used
594 on Intel systems and as fallback.
595 The code is only active when needed (enough memory and limited
596 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
600 bool "IBM Calgary IOMMU support"
602 depends on X86_64 && PCI && EXPERIMENTAL
604 Support for hardware IOMMUs in IBM's xSeries x366 and x460
605 systems. Needed to run systems with more than 3GB of memory
606 properly with 32-bit PCI devices that do not support DAC
607 (Double Address Cycle). Calgary also supports bus level
608 isolation, where all DMAs pass through the IOMMU. This
609 prevents them from going anywhere except their intended
610 destination. This catches hard-to-find kernel bugs and
611 mis-behaving drivers and devices that do not use the DMA-API
612 properly to set up their DMA buffers. The IOMMU can be
613 turned off at boot time with the iommu=off parameter.
614 Normally the kernel will make the right choice by itself.
617 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
619 prompt "Should Calgary be enabled by default?"
620 depends on CALGARY_IOMMU
622 Should Calgary be enabled by default? if you choose 'y', Calgary
623 will be used (if it exists). If you choose 'n', Calgary will not be
624 used even if it exists. If you choose 'n' and would like to use
625 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
629 bool "AMD IOMMU support"
632 depends on X86_64 && PCI && ACPI
634 With this option you can enable support for AMD IOMMU hardware in
635 your system. An IOMMU is a hardware component which provides
636 remapping of DMA memory accesses from devices. With an AMD IOMMU you
637 can isolate the the DMA memory of different devices and protect the
638 system from misbehaving device drivers or hardware.
640 You can find out if your system has an AMD IOMMU if you look into
641 your BIOS for an option to enable it or if you have an IVRS ACPI
644 config AMD_IOMMU_STATS
645 bool "Export AMD IOMMU statistics to debugfs"
649 This option enables code in the AMD IOMMU driver to collect various
650 statistics about whats happening in the driver and exports that
651 information to userspace via debugfs.
654 # need this always selected by IOMMU for the VIA workaround
658 Support for software bounce buffers used on x86-64 systems
659 which don't have a hardware IOMMU (e.g. the current generation
660 of Intel's x86-64 CPUs). Using this PCI devices which can only
661 access 32-bits of memory can be used on systems with more than
662 3 GB of memory. If unsure, say Y.
665 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
668 def_bool (AMD_IOMMU || DMAR)
671 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
672 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
673 select CPUMASK_OFFSTACK
676 Configure maximum number of CPUS and NUMA Nodes for this architecture.
680 int "Maximum number of CPUs" if SMP && !MAXSMP
681 range 2 8 if SMP && X86_32 && !X86_BIGSMP
682 range 2 512 if SMP && !MAXSMP
684 default "4096" if MAXSMP
685 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
688 This allows you to specify the maximum number of CPUs which this
689 kernel will support. The maximum supported value is 512 and the
690 minimum value which makes sense is 2.
692 This is purely to save memory - each supported CPU adds
693 approximately eight kilobytes to the kernel image.
696 bool "SMT (Hyperthreading) scheduler support"
699 SMT scheduler support improves the CPU scheduler's decision making
700 when dealing with Intel Pentium 4 chips with HyperThreading at a
701 cost of slightly increased overhead in some places. If unsure say
706 prompt "Multi-core scheduler support"
709 Multi-core scheduler support improves the CPU scheduler's decision
710 making when dealing with multi-core CPU chips at a cost of slightly
711 increased overhead in some places. If unsure say N here.
713 source "kernel/Kconfig.preempt"
716 bool "Local APIC support on uniprocessors"
717 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
719 A local APIC (Advanced Programmable Interrupt Controller) is an
720 integrated interrupt controller in the CPU. If you have a single-CPU
721 system which has a processor with a local APIC, you can say Y here to
722 enable and use it. If you say Y here even though your machine doesn't
723 have a local APIC, then the kernel will still run with no slowdown at
724 all. The local APIC supports CPU-generated self-interrupts (timer,
725 performance counters), and the NMI watchdog which detects hard
729 bool "IO-APIC support on uniprocessors"
730 depends on X86_UP_APIC
732 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
733 SMP-capable replacement for PC-style interrupt controllers. Most
734 SMP systems and many recent uniprocessor systems have one.
736 If you have a single-CPU system with an IO-APIC, you can say Y here
737 to use it. If you say Y here even though your machine doesn't have
738 an IO-APIC, then the kernel will still run with no slowdown at all.
740 config X86_LOCAL_APIC
742 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
743 select HAVE_PERF_COUNTERS if (!M386 && !M486)
747 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
749 config X86_VISWS_APIC
751 depends on X86_32 && X86_VISWS
753 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
754 bool "Reroute for broken boot IRQs"
756 depends on X86_IO_APIC
758 This option enables a workaround that fixes a source of
759 spurious interrupts. This is recommended when threaded
760 interrupt handling is used on systems where the generation of
761 superfluous "boot interrupts" cannot be disabled.
763 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
764 entry in the chipset's IO-APIC is masked (as, e.g. the RT
765 kernel does during interrupt handling). On chipsets where this
766 boot IRQ generation cannot be disabled, this workaround keeps
767 the original IRQ line masked so that only the equivalent "boot
768 IRQ" is delivered to the CPUs. The workaround also tells the
769 kernel to set up the IRQ handler on the boot IRQ line. In this
770 way only one interrupt is delivered to the kernel. Otherwise
771 the spurious second interrupt may cause the kernel to bring
772 down (vital) interrupt lines.
774 Only affects "broken" chipsets. Interrupt sharing may be
775 increased on these systems.
778 bool "Machine Check Exception"
780 Machine Check Exception support allows the processor to notify the
781 kernel if it detects a problem (e.g. overheating, component failure).
782 The action the kernel takes depends on the severity of the problem,
783 ranging from a warning message on the console, to halting the machine.
784 Your processor must be a Pentium or newer to support this - check the
785 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
786 have a design flaw which leads to false MCE events - hence MCE is
787 disabled on all P5 processors, unless explicitly enabled with "mce"
788 as a boot argument. Similarly, if MCE is built in and creates a
789 problem on some new non-standard machine, you can boot with "nomce"
790 to disable it. MCE support simply ignores non-MCE processors like
791 the 386 and 486, so nearly everyone can say Y here.
794 depends on X86_32 && X86_MCE
795 bool "Use legacy machine check code (will go away)"
797 select X86_ANCIENT_MCE
799 Use the old i386 machine check code. This is merely intended for
800 testing in a transition period. Try this if you run into any machine
801 check related software problems, but report the problem to
802 linux-kernel. When in doubt say no.
807 default y if (!X86_OLD_MCE && X86_32) || X86_64
811 prompt "Intel MCE features"
812 depends on X86_NEW_MCE && X86_LOCAL_APIC
814 Additional support for intel specific MCE features such as
819 prompt "AMD MCE features"
820 depends on X86_NEW_MCE && X86_LOCAL_APIC
822 Additional support for AMD specific MCE features such as
823 the DRAM Error Threshold.
825 config X86_ANCIENT_MCE
828 prompt "Support for old Pentium 5 / WinChip machine checks"
830 Include support for machine check handling on old Pentium 5 or WinChip
831 systems. These typically need to be enabled explicitely on the command
834 config X86_MCE_THRESHOLD
835 depends on X86_MCE_AMD || X86_MCE_INTEL
839 config X86_MCE_INJECT
840 depends on X86_NEW_MCE
841 tristate "Machine check injector support"
843 Provide support for injecting machine checks for testing purposes.
844 If you don't know what a machine check is and you don't do kernel
845 QA it is safe to say n.
847 config X86_MCE_NONFATAL
848 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
849 depends on X86_OLD_MCE
851 Enabling this feature starts a timer that triggers every 5 seconds which
852 will look at the machine check registers to see if anything happened.
853 Non-fatal problems automatically get corrected (but still logged).
854 Disable this if you don't want to see these messages.
855 Seeing the messages this option prints out may be indicative of dying
856 or out-of-spec (ie, overclocked) hardware.
857 This option only does something on certain CPUs.
858 (AMD Athlon/Duron and Intel Pentium 4)
860 config X86_MCE_P4THERMAL
861 bool "check for P4 thermal throttling interrupt."
862 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
864 Enabling this feature will cause a message to be printed when the P4
865 enters thermal throttling.
867 config X86_THERMAL_VECTOR
869 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
872 bool "Enable VM86 support" if EMBEDDED
876 This option is required by programs like DOSEMU to run 16-bit legacy
877 code on X86 processors. It also may be needed by software like
878 XFree86 to initialize some video cards via BIOS. Disabling this
879 option saves about 6k.
882 tristate "Toshiba Laptop support"
885 This adds a driver to safely access the System Management Mode of
886 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
887 not work on models with a Phoenix BIOS. The System Management Mode
888 is used to set the BIOS and power saving options on Toshiba portables.
890 For information on utilities to make use of this driver see the
891 Toshiba Linux utilities web site at:
892 <http://www.buzzard.org.uk/toshiba/>.
894 Say Y if you intend to run this kernel on a Toshiba portable.
898 tristate "Dell laptop support"
900 This adds a driver to safely access the System Management Mode
901 of the CPU on the Dell Inspiron 8000. The System Management Mode
902 is used to read cpu temperature and cooling fan status and to
903 control the fans on the I8K portables.
905 This driver has been tested only on the Inspiron 8000 but it may
906 also work with other Dell laptops. You can force loading on other
907 models by passing the parameter `force=1' to the module. Use at
910 For information on utilities to make use of this driver see the
911 I8K Linux utilities web site at:
912 <http://people.debian.org/~dz/i8k/>
914 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
917 config X86_REBOOTFIXUPS
918 bool "Enable X86 board specific fixups for reboot"
921 This enables chipset and/or board specific fixups to be done
922 in order to get reboot to work correctly. This is only needed on
923 some combinations of hardware and BIOS. The symptom, for which
924 this config is intended, is when reboot ends with a stalled/hung
927 Currently, the only fixup is for the Geode machines using
928 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
930 Say Y if you want to enable the fixup. Currently, it's safe to
931 enable this option even if you don't need it.
935 tristate "/dev/cpu/microcode - microcode support"
938 If you say Y here, you will be able to update the microcode on
939 certain Intel and AMD processors. The Intel support is for the
940 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
941 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
942 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
943 You will obviously need the actual microcode binary data itself
944 which is not shipped with the Linux kernel.
946 This option selects the general module only, you need to select
947 at least one vendor specific module as well.
949 To compile this driver as a module, choose M here: the
950 module will be called microcode.
952 config MICROCODE_INTEL
953 bool "Intel microcode patch loading support"
958 This options enables microcode patch loading support for Intel
961 For latest news and information on obtaining all the required
962 Intel ingredients for this driver, check:
963 <http://www.urbanmyth.org/microcode/>.
966 bool "AMD microcode patch loading support"
970 If you select this option, microcode patch loading support for AMD
971 processors will be enabled.
973 config MICROCODE_OLD_INTERFACE
978 tristate "/dev/cpu/*/msr - Model-specific register support"
980 This device gives privileged processes access to the x86
981 Model-Specific Registers (MSRs). It is a character device with
982 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
983 MSR accesses are directed to a specific CPU on multi-processor
987 tristate "/dev/cpu/*/cpuid - CPU information support"
989 This device gives processes access to the x86 CPUID instruction to
990 be executed on a specific processor. It is a character device
991 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
995 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
997 If you select this option, this will provide various x86 CPUs
998 information through debugfs.
1001 prompt "High Memory Support"
1002 default HIGHMEM4G if !X86_NUMAQ
1003 default HIGHMEM64G if X86_NUMAQ
1008 depends on !X86_NUMAQ
1010 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1011 However, the address space of 32-bit x86 processors is only 4
1012 Gigabytes large. That means that, if you have a large amount of
1013 physical memory, not all of it can be "permanently mapped" by the
1014 kernel. The physical memory that's not permanently mapped is called
1017 If you are compiling a kernel which will never run on a machine with
1018 more than 1 Gigabyte total physical RAM, answer "off" here (default
1019 choice and suitable for most users). This will result in a "3GB/1GB"
1020 split: 3GB are mapped so that each process sees a 3GB virtual memory
1021 space and the remaining part of the 4GB virtual memory space is used
1022 by the kernel to permanently map as much physical memory as
1025 If the machine has between 1 and 4 Gigabytes physical RAM, then
1028 If more than 4 Gigabytes is used then answer "64GB" here. This
1029 selection turns Intel PAE (Physical Address Extension) mode on.
1030 PAE implements 3-level paging on IA32 processors. PAE is fully
1031 supported by Linux, PAE mode is implemented on all recent Intel
1032 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1033 then the kernel will not boot on CPUs that don't support PAE!
1035 The actual amount of total physical memory will either be
1036 auto detected or can be forced by using a kernel command line option
1037 such as "mem=256M". (Try "man bootparam" or see the documentation of
1038 your boot loader (lilo or loadlin) about how to pass options to the
1039 kernel at boot time.)
1041 If unsure, say "off".
1045 depends on !X86_NUMAQ
1047 Select this if you have a 32-bit processor and between 1 and 4
1048 gigabytes of physical RAM.
1052 depends on !M386 && !M486
1055 Select this if you have a 32-bit processor and more than 4
1056 gigabytes of physical RAM.
1061 depends on EXPERIMENTAL
1062 prompt "Memory split" if EMBEDDED
1066 Select the desired split between kernel and user memory.
1068 If the address range available to the kernel is less than the
1069 physical memory installed, the remaining memory will be available
1070 as "high memory". Accessing high memory is a little more costly
1071 than low memory, as it needs to be mapped into the kernel first.
1072 Note that increasing the kernel address space limits the range
1073 available to user programs, making the address space there
1074 tighter. Selecting anything other than the default 3G/1G split
1075 will also likely make your kernel incompatible with binary-only
1078 If you are not absolutely sure what you are doing, leave this
1082 bool "3G/1G user/kernel split"
1083 config VMSPLIT_3G_OPT
1085 bool "3G/1G user/kernel split (for full 1G low memory)"
1087 bool "2G/2G user/kernel split"
1088 config VMSPLIT_2G_OPT
1090 bool "2G/2G user/kernel split (for full 2G low memory)"
1092 bool "1G/3G user/kernel split"
1097 default 0xB0000000 if VMSPLIT_3G_OPT
1098 default 0x80000000 if VMSPLIT_2G
1099 default 0x78000000 if VMSPLIT_2G_OPT
1100 default 0x40000000 if VMSPLIT_1G
1106 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1109 bool "PAE (Physical Address Extension) Support"
1110 depends on X86_32 && !HIGHMEM4G
1112 PAE is required for NX support, and furthermore enables
1113 larger swapspace support for non-overcommit purposes. It
1114 has the cost of more pagetable lookup overhead, and also
1115 consumes more pagetable space per process.
1117 config ARCH_PHYS_ADDR_T_64BIT
1118 def_bool X86_64 || X86_PAE
1120 config DIRECT_GBPAGES
1121 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1125 Allow the kernel linear mapping to use 1GB pages on CPUs that
1126 support it. This can improve the kernel's performance a tiny bit by
1127 reducing TLB pressure. If in doubt, say "Y".
1129 # Common NUMA Features
1131 bool "Numa Memory Allocation and Scheduler Support"
1133 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1134 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1136 Enable NUMA (Non Uniform Memory Access) support.
1138 The kernel will try to allocate memory used by a CPU on the
1139 local memory controller of the CPU and add some more
1140 NUMA awareness to the kernel.
1142 For 64-bit this is recommended if the system is Intel Core i7
1143 (or later), AMD Opteron, or EM64T NUMA.
1145 For 32-bit this is only needed on (rare) 32-bit-only platforms
1146 that support NUMA topologies, such as NUMAQ / Summit, or if you
1147 boot a 32-bit kernel on a 64-bit NUMA platform.
1149 Otherwise, you should say N.
1151 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1152 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1156 prompt "Old style AMD Opteron NUMA detection"
1157 depends on X86_64 && NUMA && PCI
1159 Enable K8 NUMA node topology detection. You should say Y here if
1160 you have a multi processor AMD K8 system. This uses an old
1161 method to read the NUMA configuration directly from the builtin
1162 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1163 instead, which also takes priority if both are compiled in.
1165 config X86_64_ACPI_NUMA
1167 prompt "ACPI NUMA detection"
1168 depends on X86_64 && NUMA && ACPI && PCI
1171 Enable ACPI SRAT based node topology detection.
1173 # Some NUMA nodes have memory ranges that span
1174 # other nodes. Even though a pfn is valid and
1175 # between a node's start and end pfns, it may not
1176 # reside on that node. See memmap_init_zone()
1178 config NODES_SPAN_OTHER_NODES
1180 depends on X86_64_ACPI_NUMA
1183 bool "NUMA emulation"
1184 depends on X86_64 && NUMA
1186 Enable NUMA emulation. A flat machine will be split
1187 into virtual nodes when booted with "numa=fake=N", where N is the
1188 number of nodes. This is only useful for debugging.
1191 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1193 default "9" if MAXSMP
1194 default "6" if X86_64
1195 default "4" if X86_NUMAQ
1197 depends on NEED_MULTIPLE_NODES
1199 Specify the maximum number of NUMA Nodes available on the target
1200 system. Increases memory reserved to accommodate various tables.
1202 config HAVE_ARCH_BOOTMEM
1204 depends on X86_32 && NUMA
1206 config ARCH_HAVE_MEMORY_PRESENT
1208 depends on X86_32 && DISCONTIGMEM
1210 config NEED_NODE_MEMMAP_SIZE
1212 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1214 config HAVE_ARCH_ALLOC_REMAP
1216 depends on X86_32 && NUMA
1218 config ARCH_FLATMEM_ENABLE
1220 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1222 config ARCH_DISCONTIGMEM_ENABLE
1224 depends on NUMA && X86_32
1226 config ARCH_DISCONTIGMEM_DEFAULT
1228 depends on NUMA && X86_32
1230 config ARCH_SPARSEMEM_DEFAULT
1234 config ARCH_SPARSEMEM_ENABLE
1236 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1237 select SPARSEMEM_STATIC if X86_32
1238 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1240 config ARCH_SELECT_MEMORY_MODEL
1242 depends on ARCH_SPARSEMEM_ENABLE
1244 config ARCH_MEMORY_PROBE
1246 depends on MEMORY_HOTPLUG
1251 bool "Allocate 3rd-level pagetables from highmem"
1252 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1254 The VM uses one page table entry for each page of physical memory.
1255 For systems with a lot of RAM, this can be wasteful of precious
1256 low memory. Setting this option will put user-space page table
1257 entries in high memory.
1259 config X86_CHECK_BIOS_CORRUPTION
1260 bool "Check for low memory corruption"
1262 Periodically check for memory corruption in low memory, which
1263 is suspected to be caused by BIOS. Even when enabled in the
1264 configuration, it is disabled at runtime. Enable it by
1265 setting "memory_corruption_check=1" on the kernel command
1266 line. By default it scans the low 64k of memory every 60
1267 seconds; see the memory_corruption_check_size and
1268 memory_corruption_check_period parameters in
1269 Documentation/kernel-parameters.txt to adjust this.
1271 When enabled with the default parameters, this option has
1272 almost no overhead, as it reserves a relatively small amount
1273 of memory and scans it infrequently. It both detects corruption
1274 and prevents it from affecting the running system.
1276 It is, however, intended as a diagnostic tool; if repeatable
1277 BIOS-originated corruption always affects the same memory,
1278 you can use memmap= to prevent the kernel from using that
1281 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1282 bool "Set the default setting of memory_corruption_check"
1283 depends on X86_CHECK_BIOS_CORRUPTION
1286 Set whether the default state of memory_corruption_check is
1289 config X86_RESERVE_LOW_64K
1290 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1293 Reserve the first 64K of physical RAM on BIOSes that are known
1294 to potentially corrupt that memory range. A numbers of BIOSes are
1295 known to utilize this area during suspend/resume, so it must not
1296 be used by the kernel.
1298 Set this to N if you are absolutely sure that you trust the BIOS
1299 to get all its memory reservations and usages right.
1301 If you have doubts about the BIOS (e.g. suspend/resume does not
1302 work or there's kernel crashes after certain hardware hotplug
1303 events) and it's not AMI or Phoenix, then you might want to enable
1304 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1305 corruption patterns.
1309 config MATH_EMULATION
1311 prompt "Math emulation" if X86_32
1313 Linux can emulate a math coprocessor (used for floating point
1314 operations) if you don't have one. 486DX and Pentium processors have
1315 a math coprocessor built in, 486SX and 386 do not, unless you added
1316 a 487DX or 387, respectively. (The messages during boot time can
1317 give you some hints here ["man dmesg"].) Everyone needs either a
1318 coprocessor or this emulation.
1320 If you don't have a math coprocessor, you need to say Y here; if you
1321 say Y here even though you have a coprocessor, the coprocessor will
1322 be used nevertheless. (This behavior can be changed with the kernel
1323 command line option "no387", which comes handy if your coprocessor
1324 is broken. Try "man bootparam" or see the documentation of your boot
1325 loader (lilo or loadlin) about how to pass options to the kernel at
1326 boot time.) This means that it is a good idea to say Y here if you
1327 intend to use this kernel on different machines.
1329 More information about the internals of the Linux math coprocessor
1330 emulation can be found in <file:arch/x86/math-emu/README>.
1332 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1333 kernel, it won't hurt.
1336 bool "MTRR (Memory Type Range Register) support"
1338 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1339 the Memory Type Range Registers (MTRRs) may be used to control
1340 processor access to memory ranges. This is most useful if you have
1341 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1342 allows bus write transfers to be combined into a larger transfer
1343 before bursting over the PCI/AGP bus. This can increase performance
1344 of image write operations 2.5 times or more. Saying Y here creates a
1345 /proc/mtrr file which may be used to manipulate your processor's
1346 MTRRs. Typically the X server should use this.
1348 This code has a reasonably generic interface so that similar
1349 control registers on other processors can be easily supported
1352 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1353 Registers (ARRs) which provide a similar functionality to MTRRs. For
1354 these, the ARRs are used to emulate the MTRRs.
1355 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1356 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1357 write-combining. All of these processors are supported by this code
1358 and it makes sense to say Y here if you have one of them.
1360 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1361 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1362 can lead to all sorts of problems, so it's good to say Y here.
1364 You can safely say Y even if your machine doesn't have MTRRs, you'll
1365 just add about 9 KB to your kernel.
1367 See <file:Documentation/x86/mtrr.txt> for more information.
1369 config MTRR_SANITIZER
1371 prompt "MTRR cleanup support"
1374 Convert MTRR layout from continuous to discrete, so X drivers can
1375 add writeback entries.
1377 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1378 The largest mtrr entry size for a continuous block can be set with
1383 config MTRR_SANITIZER_ENABLE_DEFAULT
1384 int "MTRR cleanup enable value (0-1)"
1387 depends on MTRR_SANITIZER
1389 Enable mtrr cleanup default value
1391 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1392 int "MTRR cleanup spare reg num (0-7)"
1395 depends on MTRR_SANITIZER
1397 mtrr cleanup spare entries default, it can be changed via
1398 mtrr_spare_reg_nr=N on the kernel command line.
1402 prompt "x86 PAT support"
1405 Use PAT attributes to setup page level cache control.
1407 PATs are the modern equivalents of MTRRs and are much more
1408 flexible than MTRRs.
1410 Say N here if you see bootup problems (boot crash, boot hang,
1411 spontaneous reboots) or a non-working video driver.
1416 bool "EFI runtime service support"
1419 This enables the kernel to use EFI runtime services that are
1420 available (such as the EFI variable services).
1422 This option is only useful on systems that have EFI firmware.
1423 In addition, you should use the latest ELILO loader available
1424 at <http://elilo.sourceforge.net> in order to take advantage
1425 of EFI runtime services. However, even with this option, the
1426 resultant kernel should continue to boot on existing non-EFI
1431 prompt "Enable seccomp to safely compute untrusted bytecode"
1433 This kernel feature is useful for number crunching applications
1434 that may need to compute untrusted bytecode during their
1435 execution. By using pipes or other transports made available to
1436 the process as file descriptors supporting the read/write
1437 syscalls, it's possible to isolate those applications in
1438 their own address space using seccomp. Once seccomp is
1439 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1440 and the task is only allowed to execute a few safe syscalls
1441 defined by each seccomp mode.
1443 If unsure, say Y. Only embedded should say N here.
1445 config CC_STACKPROTECTOR_ALL
1448 config CC_STACKPROTECTOR
1449 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1450 select CC_STACKPROTECTOR_ALL
1452 This option turns on the -fstack-protector GCC feature. This
1453 feature puts, at the beginning of functions, a canary value on
1454 the stack just before the return address, and validates
1455 the value just before actually returning. Stack based buffer
1456 overflows (that need to overwrite this return address) now also
1457 overwrite the canary, which gets detected and the attack is then
1458 neutralized via a kernel panic.
1460 This feature requires gcc version 4.2 or above, or a distribution
1461 gcc with the feature backported. Older versions are automatically
1462 detected and for those versions, this configuration option is
1463 ignored. (and a warning is printed during bootup)
1465 source kernel/Kconfig.hz
1468 bool "kexec system call"
1470 kexec is a system call that implements the ability to shutdown your
1471 current kernel, and to start another kernel. It is like a reboot
1472 but it is independent of the system firmware. And like a reboot
1473 you can start any kernel with it, not just Linux.
1475 The name comes from the similarity to the exec system call.
1477 It is an ongoing process to be certain the hardware in a machine
1478 is properly shutdown, so do not be surprised if this code does not
1479 initially work for you. It may help to enable device hotplugging
1480 support. As of this writing the exact hardware interface is
1481 strongly in flux, so no good recommendation can be made.
1484 bool "kernel crash dumps"
1485 depends on X86_64 || (X86_32 && HIGHMEM)
1487 Generate crash dump after being started by kexec.
1488 This should be normally only set in special crash dump kernels
1489 which are loaded in the main kernel with kexec-tools into
1490 a specially reserved region and then later executed after
1491 a crash by kdump/kexec. The crash dump kernel must be compiled
1492 to a memory address not used by the main kernel or BIOS using
1493 PHYSICAL_START, or it must be built as a relocatable image
1494 (CONFIG_RELOCATABLE=y).
1495 For more details see Documentation/kdump/kdump.txt
1498 bool "kexec jump (EXPERIMENTAL)"
1499 depends on EXPERIMENTAL
1500 depends on KEXEC && HIBERNATION
1502 Jump between original kernel and kexeced kernel and invoke
1503 code in physical address mode via KEXEC
1505 config PHYSICAL_START
1506 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1509 This gives the physical address where the kernel is loaded.
1511 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1512 bzImage will decompress itself to above physical address and
1513 run from there. Otherwise, bzImage will run from the address where
1514 it has been loaded by the boot loader and will ignore above physical
1517 In normal kdump cases one does not have to set/change this option
1518 as now bzImage can be compiled as a completely relocatable image
1519 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1520 address. This option is mainly useful for the folks who don't want
1521 to use a bzImage for capturing the crash dump and want to use a
1522 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1523 to be specifically compiled to run from a specific memory area
1524 (normally a reserved region) and this option comes handy.
1526 So if you are using bzImage for capturing the crash dump,
1527 leave the value here unchanged to 0x1000000 and set
1528 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1529 for capturing the crash dump change this value to start of
1530 the reserved region. In other words, it can be set based on
1531 the "X" value as specified in the "crashkernel=YM@XM"
1532 command line boot parameter passed to the panic-ed
1533 kernel. Please take a look at Documentation/kdump/kdump.txt
1534 for more details about crash dumps.
1536 Usage of bzImage for capturing the crash dump is recommended as
1537 one does not have to build two kernels. Same kernel can be used
1538 as production kernel and capture kernel. Above option should have
1539 gone away after relocatable bzImage support is introduced. But it
1540 is present because there are users out there who continue to use
1541 vmlinux for dump capture. This option should go away down the
1544 Don't change this unless you know what you are doing.
1547 bool "Build a relocatable kernel"
1550 This builds a kernel image that retains relocation information
1551 so it can be loaded someplace besides the default 1MB.
1552 The relocations tend to make the kernel binary about 10% larger,
1553 but are discarded at runtime.
1555 One use is for the kexec on panic case where the recovery kernel
1556 must live at a different physical address than the primary
1559 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1560 it has been loaded at and the compile time physical address
1561 (CONFIG_PHYSICAL_START) is ignored.
1563 # Relocation on x86-32 needs some additional build support
1564 config X86_NEED_RELOCS
1566 depends on X86_32 && RELOCATABLE
1568 config PHYSICAL_ALIGN
1570 prompt "Alignment value to which kernel should be aligned" if X86_32
1572 range 0x2000 0x1000000
1574 This value puts the alignment restrictions on physical address
1575 where kernel is loaded and run from. Kernel is compiled for an
1576 address which meets above alignment restriction.
1578 If bootloader loads the kernel at a non-aligned address and
1579 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1580 address aligned to above value and run from there.
1582 If bootloader loads the kernel at a non-aligned address and
1583 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1584 load address and decompress itself to the address it has been
1585 compiled for and run from there. The address for which kernel is
1586 compiled already meets above alignment restrictions. Hence the
1587 end result is that kernel runs from a physical address meeting
1588 above alignment restrictions.
1590 Don't change this unless you know what you are doing.
1593 bool "Support for hot-pluggable CPUs"
1594 depends on SMP && HOTPLUG
1596 Say Y here to allow turning CPUs off and on. CPUs can be
1597 controlled through /sys/devices/system/cpu.
1598 ( Note: power management support will enable this option
1599 automatically on SMP systems. )
1600 Say N if you want to disable CPU hotplug.
1604 prompt "Compat VDSO support"
1605 depends on X86_32 || IA32_EMULATION
1607 Map the 32-bit VDSO to the predictable old-style address too.
1609 Say N here if you are running a sufficiently recent glibc
1610 version (2.3.3 or later), to remove the high-mapped
1611 VDSO mapping and to exclusively use the randomized VDSO.
1616 bool "Built-in kernel command line"
1619 Allow for specifying boot arguments to the kernel at
1620 build time. On some systems (e.g. embedded ones), it is
1621 necessary or convenient to provide some or all of the
1622 kernel boot arguments with the kernel itself (that is,
1623 to not rely on the boot loader to provide them.)
1625 To compile command line arguments into the kernel,
1626 set this option to 'Y', then fill in the
1627 the boot arguments in CONFIG_CMDLINE.
1629 Systems with fully functional boot loaders (i.e. non-embedded)
1630 should leave this option set to 'N'.
1633 string "Built-in kernel command string"
1634 depends on CMDLINE_BOOL
1637 Enter arguments here that should be compiled into the kernel
1638 image and used at boot time. If the boot loader provides a
1639 command line at boot time, it is appended to this string to
1640 form the full kernel command line, when the system boots.
1642 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1643 change this behavior.
1645 In most cases, the command line (whether built-in or provided
1646 by the boot loader) should specify the device for the root
1649 config CMDLINE_OVERRIDE
1650 bool "Built-in command line overrides boot loader arguments"
1652 depends on CMDLINE_BOOL
1654 Set this option to 'Y' to have the kernel ignore the boot loader
1655 command line, and use ONLY the built-in command line.
1657 This is used to work around broken boot loaders. This should
1658 be set to 'N' under normal conditions.
1662 config ARCH_ENABLE_MEMORY_HOTPLUG
1664 depends on X86_64 || (X86_32 && HIGHMEM)
1666 config ARCH_ENABLE_MEMORY_HOTREMOVE
1668 depends on MEMORY_HOTPLUG
1670 config HAVE_ARCH_EARLY_PFN_TO_NID
1674 menu "Power management and ACPI options"
1676 config ARCH_HIBERNATION_HEADER
1678 depends on X86_64 && HIBERNATION
1680 source "kernel/power/Kconfig"
1682 source "drivers/acpi/Kconfig"
1687 depends on APM || APM_MODULE
1690 tristate "APM (Advanced Power Management) BIOS support"
1691 depends on X86_32 && PM_SLEEP
1693 APM is a BIOS specification for saving power using several different
1694 techniques. This is mostly useful for battery powered laptops with
1695 APM compliant BIOSes. If you say Y here, the system time will be
1696 reset after a RESUME operation, the /proc/apm device will provide
1697 battery status information, and user-space programs will receive
1698 notification of APM "events" (e.g. battery status change).
1700 If you select "Y" here, you can disable actual use of the APM
1701 BIOS by passing the "apm=off" option to the kernel at boot time.
1703 Note that the APM support is almost completely disabled for
1704 machines with more than one CPU.
1706 In order to use APM, you will need supporting software. For location
1707 and more information, read <file:Documentation/power/pm.txt> and the
1708 Battery Powered Linux mini-HOWTO, available from
1709 <http://www.tldp.org/docs.html#howto>.
1711 This driver does not spin down disk drives (see the hdparm(8)
1712 manpage ("man 8 hdparm") for that), and it doesn't turn off
1713 VESA-compliant "green" monitors.
1715 This driver does not support the TI 4000M TravelMate and the ACER
1716 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1717 desktop machines also don't have compliant BIOSes, and this driver
1718 may cause those machines to panic during the boot phase.
1720 Generally, if you don't have a battery in your machine, there isn't
1721 much point in using this driver and you should say N. If you get
1722 random kernel OOPSes or reboots that don't seem to be related to
1723 anything, try disabling/enabling this option (or disabling/enabling
1726 Some other things you should try when experiencing seemingly random,
1729 1) make sure that you have enough swap space and that it is
1731 2) pass the "no-hlt" option to the kernel
1732 3) switch on floating point emulation in the kernel and pass
1733 the "no387" option to the kernel
1734 4) pass the "floppy=nodma" option to the kernel
1735 5) pass the "mem=4M" option to the kernel (thereby disabling
1736 all but the first 4 MB of RAM)
1737 6) make sure that the CPU is not over clocked.
1738 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1739 8) disable the cache from your BIOS settings
1740 9) install a fan for the video card or exchange video RAM
1741 10) install a better fan for the CPU
1742 11) exchange RAM chips
1743 12) exchange the motherboard.
1745 To compile this driver as a module, choose M here: the
1746 module will be called apm.
1750 config APM_IGNORE_USER_SUSPEND
1751 bool "Ignore USER SUSPEND"
1753 This option will ignore USER SUSPEND requests. On machines with a
1754 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1755 series notebooks, it is necessary to say Y because of a BIOS bug.
1757 config APM_DO_ENABLE
1758 bool "Enable PM at boot time"
1760 Enable APM features at boot time. From page 36 of the APM BIOS
1761 specification: "When disabled, the APM BIOS does not automatically
1762 power manage devices, enter the Standby State, enter the Suspend
1763 State, or take power saving steps in response to CPU Idle calls."
1764 This driver will make CPU Idle calls when Linux is idle (unless this
1765 feature is turned off -- see "Do CPU IDLE calls", below). This
1766 should always save battery power, but more complicated APM features
1767 will be dependent on your BIOS implementation. You may need to turn
1768 this option off if your computer hangs at boot time when using APM
1769 support, or if it beeps continuously instead of suspending. Turn
1770 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1771 T400CDT. This is off by default since most machines do fine without
1775 bool "Make CPU Idle calls when idle"
1777 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1778 On some machines, this can activate improved power savings, such as
1779 a slowed CPU clock rate, when the machine is idle. These idle calls
1780 are made after the idle loop has run for some length of time (e.g.,
1781 333 mS). On some machines, this will cause a hang at boot time or
1782 whenever the CPU becomes idle. (On machines with more than one CPU,
1783 this option does nothing.)
1785 config APM_DISPLAY_BLANK
1786 bool "Enable console blanking using APM"
1788 Enable console blanking using the APM. Some laptops can use this to
1789 turn off the LCD backlight when the screen blanker of the Linux
1790 virtual console blanks the screen. Note that this is only used by
1791 the virtual console screen blanker, and won't turn off the backlight
1792 when using the X Window system. This also doesn't have anything to
1793 do with your VESA-compliant power-saving monitor. Further, this
1794 option doesn't work for all laptops -- it might not turn off your
1795 backlight at all, or it might print a lot of errors to the console,
1796 especially if you are using gpm.
1798 config APM_ALLOW_INTS
1799 bool "Allow interrupts during APM BIOS calls"
1801 Normally we disable external interrupts while we are making calls to
1802 the APM BIOS as a measure to lessen the effects of a badly behaving
1803 BIOS implementation. The BIOS should reenable interrupts if it
1804 needs to. Unfortunately, some BIOSes do not -- especially those in
1805 many of the newer IBM Thinkpads. If you experience hangs when you
1806 suspend, try setting this to Y. Otherwise, say N.
1810 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1812 source "drivers/cpuidle/Kconfig"
1814 source "drivers/idle/Kconfig"
1819 menu "Bus options (PCI etc.)"
1824 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1826 Find out whether you have a PCI motherboard. PCI is the name of a
1827 bus system, i.e. the way the CPU talks to the other stuff inside
1828 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1829 VESA. If you have PCI, say Y, otherwise N.
1832 prompt "PCI access mode"
1833 depends on X86_32 && PCI
1836 On PCI systems, the BIOS can be used to detect the PCI devices and
1837 determine their configuration. However, some old PCI motherboards
1838 have BIOS bugs and may crash if this is done. Also, some embedded
1839 PCI-based systems don't have any BIOS at all. Linux can also try to
1840 detect the PCI hardware directly without using the BIOS.
1842 With this option, you can specify how Linux should detect the
1843 PCI devices. If you choose "BIOS", the BIOS will be used,
1844 if you choose "Direct", the BIOS won't be used, and if you
1845 choose "MMConfig", then PCI Express MMCONFIG will be used.
1846 If you choose "Any", the kernel will try MMCONFIG, then the
1847 direct access method and falls back to the BIOS if that doesn't
1848 work. If unsure, go with the default, which is "Any".
1853 config PCI_GOMMCONFIG
1870 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1872 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1875 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1879 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1883 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1890 bool "Support mmconfig PCI config space access"
1891 depends on X86_64 && PCI && ACPI
1894 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1895 depends on PCI_MSI && ACPI && EXPERIMENTAL
1897 DMA remapping (DMAR) devices support enables independent address
1898 translations for Direct Memory Access (DMA) from devices.
1899 These DMA remapping devices are reported via ACPI tables
1900 and include PCI device scope covered by these DMA
1903 config DMAR_DEFAULT_ON
1905 prompt "Enable DMA Remapping Devices by default"
1908 Selecting this option will enable a DMAR device at boot time if
1909 one is found. If this option is not selected, DMAR support can
1910 be enabled by passing intel_iommu=on to the kernel. It is
1911 recommended you say N here while the DMAR code remains
1916 prompt "Support for Graphics workaround"
1919 Current Graphics drivers tend to use physical address
1920 for DMA and avoid using DMA APIs. Setting this config
1921 option permits the IOMMU driver to set a unity map for
1922 all the OS-visible memory. Hence the driver can continue
1923 to use physical addresses for DMA.
1925 config DMAR_FLOPPY_WA
1929 Floppy disk drivers are know to bypass DMA API calls
1930 thereby failing to work when IOMMU is enabled. This
1931 workaround will setup a 1:1 mapping for the first
1932 16M to make floppy (an ISA device) work.
1935 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1936 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1938 Supports Interrupt remapping for IO-APIC and MSI devices.
1939 To use x2apic mode in the CPU's which support x2APIC enhancements or
1940 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1942 source "drivers/pci/pcie/Kconfig"
1944 source "drivers/pci/Kconfig"
1946 # x86_64 have no ISA slots, but do have ISA-style DMA.
1955 Find out whether you have ISA slots on your motherboard. ISA is the
1956 name of a bus system, i.e. the way the CPU talks to the other stuff
1957 inside your box. Other bus systems are PCI, EISA, MicroChannel
1958 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1959 newer boards don't support it. If you have ISA, say Y, otherwise N.
1965 The Extended Industry Standard Architecture (EISA) bus was
1966 developed as an open alternative to the IBM MicroChannel bus.
1968 The EISA bus provided some of the features of the IBM MicroChannel
1969 bus while maintaining backward compatibility with cards made for
1970 the older ISA bus. The EISA bus saw limited use between 1988 and
1971 1995 when it was made obsolete by the PCI bus.
1973 Say Y here if you are building a kernel for an EISA-based machine.
1977 source "drivers/eisa/Kconfig"
1982 MicroChannel Architecture is found in some IBM PS/2 machines and
1983 laptops. It is a bus system similar to PCI or ISA. See
1984 <file:Documentation/mca.txt> (and especially the web page given
1985 there) before attempting to build an MCA bus kernel.
1987 source "drivers/mca/Kconfig"
1990 tristate "NatSemi SCx200 support"
1992 This provides basic support for National Semiconductor's
1993 (now AMD's) Geode processors. The driver probes for the
1994 PCI-IDs of several on-chip devices, so its a good dependency
1995 for other scx200_* drivers.
1997 If compiled as a module, the driver is named scx200.
1999 config SCx200HR_TIMER
2000 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2001 depends on SCx200 && GENERIC_TIME
2004 This driver provides a clocksource built upon the on-chip
2005 27MHz high-resolution timer. Its also a workaround for
2006 NSC Geode SC-1100's buggy TSC, which loses time when the
2007 processor goes idle (as is done by the scheduler). The
2008 other workaround is idle=poll boot option.
2010 config GEODE_MFGPT_TIMER
2012 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2013 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2015 This driver provides a clock event source based on the MFGPT
2016 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2017 MFGPTs have a better resolution and max interval than the
2018 generic PIT, and are suitable for use as high-res timers.
2021 bool "One Laptop Per Child support"
2024 Add support for detecting the unique features of the OLPC
2031 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2033 source "drivers/pcmcia/Kconfig"
2035 source "drivers/pci/hotplug/Kconfig"
2040 menu "Executable file formats / Emulations"
2042 source "fs/Kconfig.binfmt"
2044 config IA32_EMULATION
2045 bool "IA32 Emulation"
2047 select COMPAT_BINFMT_ELF
2049 Include code to run 32-bit programs under a 64-bit kernel. You should
2050 likely turn this on, unless you're 100% sure that you don't have any
2051 32-bit programs left.
2054 tristate "IA32 a.out support"
2055 depends on IA32_EMULATION
2057 Support old a.out binaries in the 32bit emulation.
2061 depends on IA32_EMULATION
2063 config COMPAT_FOR_U64_ALIGNMENT
2067 config SYSVIPC_COMPAT
2069 depends on COMPAT && SYSVIPC
2074 config HAVE_ATOMIC_IOMAP
2078 source "net/Kconfig"
2080 source "drivers/Kconfig"
2082 source "drivers/firmware/Kconfig"
2086 source "arch/x86/Kconfig.debug"
2088 source "security/Kconfig"
2090 source "crypto/Kconfig"
2092 source "arch/x86/kvm/Kconfig"
2094 source "lib/Kconfig"
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