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
52 default "arch/x86/configs/i386_defconfig" if X86_32
53 default "arch/x86/configs/x86_64_defconfig" if X86_64
58 config GENERIC_CMOS_UPDATE
61 config CLOCKSOURCE_WATCHDOG
64 config GENERIC_CLOCKEVENTS
67 config GENERIC_CLOCKEVENTS_BROADCAST
69 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
71 config LOCKDEP_SUPPORT
74 config STACKTRACE_SUPPORT
77 config HAVE_LATENCYTOP_SUPPORT
80 config FAST_CMPXCHG_LOCAL
93 config GENERIC_ISA_DMA
102 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
104 config GENERIC_BUG_RELATIVE_POINTERS
107 config GENERIC_HWEIGHT
113 config ARCH_MAY_HAVE_PC_FDC
116 config RWSEM_GENERIC_SPINLOCK
119 config RWSEM_XCHGADD_ALGORITHM
122 config ARCH_HAS_CPU_IDLE_WAIT
125 config GENERIC_CALIBRATE_DELAY
128 config GENERIC_TIME_VSYSCALL
132 config ARCH_HAS_CPU_RELAX
135 config ARCH_HAS_DEFAULT_IDLE
138 config ARCH_HAS_CACHE_LINE_SIZE
141 config HAVE_SETUP_PER_CPU_AREA
144 config HAVE_DYNAMIC_PER_CPU_AREA
147 config HAVE_CPUMASK_OF_CPU_MAP
150 config ARCH_HIBERNATION_POSSIBLE
153 config ARCH_SUSPEND_POSSIBLE
160 config ARCH_POPULATES_NODE_MAP
167 config ARCH_SUPPORTS_OPTIMIZED_INLINING
170 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
173 # Use the generic interrupt handling code in kernel/irq/:
174 config GENERIC_HARDIRQS
178 config GENERIC_HARDIRQS_NO__DO_IRQ
181 config GENERIC_IRQ_PROBE
185 config GENERIC_PENDING_IRQ
187 depends on GENERIC_HARDIRQS && SMP
190 config USE_GENERIC_SMP_HELPERS
196 depends on X86_32 && SMP
200 depends on X86_64 && SMP
207 config X86_TRAMPOLINE
209 depends on SMP || (64BIT && ACPI_SLEEP)
212 config X86_32_LAZY_GS
214 depends on X86_32 && !CC_STACKPROTECTOR
218 source "init/Kconfig"
219 source "kernel/Kconfig.freezer"
221 menu "Processor type and features"
223 source "kernel/time/Kconfig"
226 bool "Symmetric multi-processing support"
228 This enables support for systems with more than one CPU. If you have
229 a system with only one CPU, like most personal computers, say N. If
230 you have a system with more than one CPU, say Y.
232 If you say N here, the kernel will run on single and multiprocessor
233 machines, but will use only one CPU of a multiprocessor machine. If
234 you say Y here, the kernel will run on many, but not all,
235 singleprocessor machines. On a singleprocessor machine, the kernel
236 will run faster if you say N here.
238 Note that if you say Y here and choose architecture "586" or
239 "Pentium" under "Processor family", the kernel will not work on 486
240 architectures. Similarly, multiprocessor kernels for the "PPro"
241 architecture may not work on all Pentium based boards.
243 People using multiprocessor machines who say Y here should also say
244 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
245 Management" code will be disabled if you say Y here.
247 See also <file:Documentation/i386/IO-APIC.txt>,
248 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
249 <http://www.tldp.org/docs.html#howto>.
251 If you don't know what to do here, say N.
254 bool "Support x2apic"
255 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
257 This enables x2apic support on CPUs that have this feature.
259 This allows 32-bit apic IDs (so it can support very large systems),
260 and accesses the local apic via MSRs not via mmio.
262 If you don't know what to do here, say N.
265 bool "Support sparse irq numbering"
266 depends on PCI_MSI || HT_IRQ
268 This enables support for sparse irqs. This is useful for distro
269 kernels that want to define a high CONFIG_NR_CPUS value but still
270 want to have low kernel memory footprint on smaller machines.
272 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
273 out the irq_desc[] array in a more NUMA-friendly way. )
275 If you don't know what to do here, say N.
279 depends on SPARSE_IRQ && NUMA
282 bool "Enable MPS table" if ACPI
284 depends on X86_LOCAL_APIC
286 For old smp systems that do not have proper acpi support. Newer systems
287 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
290 bool "Support for big SMP systems with more than 8 CPUs"
291 depends on X86_32 && SMP
293 This option is needed for the systems that have more than 8 CPUs
296 config X86_EXTENDED_PLATFORM
297 bool "Support for extended (non-PC) x86 platforms"
300 If you disable this option then the kernel will only support
301 standard PC platforms. (which covers the vast majority of
304 If you enable this option then you'll be able to select support
305 for the following (non-PC) 32 bit x86 platforms:
309 SGI 320/540 (Visual Workstation)
310 Summit/EXA (IBM x440)
311 Unisys ES7000 IA32 series
313 If you have one of these systems, or if you want to build a
314 generic distribution kernel, say Y here - otherwise say N.
318 config X86_EXTENDED_PLATFORM
319 bool "Support for extended (non-PC) x86 platforms"
322 If you disable this option then the kernel will only support
323 standard PC platforms. (which covers the vast majority of
326 If you enable this option then you'll be able to select support
327 for the following (non-PC) 64 bit x86 platforms:
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
334 # This is an alphabetically sorted list of 64 bit extended platforms
335 # Please maintain the alphabetic order if and when there are additions
340 depends on X86_64 && PCI
341 depends on X86_EXTENDED_PLATFORM
343 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
344 supposed to run on these EM64T-based machines. Only choose this option
345 if you have one of these machines.
348 bool "SGI Ultraviolet"
350 depends on X86_EXTENDED_PLATFORM
352 depends on X86_X2APIC
354 This option is needed in order to support SGI Ultraviolet systems.
355 If you don't have one of these, you should say N here.
357 # Following is an alphabetically sorted list of 32 bit extended platforms
358 # Please maintain the alphabetic order if and when there are additions
363 depends on X86_EXTENDED_PLATFORM
365 Select this for an AMD Elan processor.
367 Do not use this option for K6/Athlon/Opteron processors!
369 If unsure, choose "PC-compatible" instead.
372 bool "RDC R-321x SoC"
374 depends on X86_EXTENDED_PLATFORM
376 select X86_REBOOTFIXUPS
378 This option is needed for RDC R-321x system-on-chip, also known
380 If you don't have one of these chips, you should say N here.
382 config X86_32_NON_STANDARD
383 bool "Support non-standard 32-bit SMP architectures"
384 depends on X86_32 && SMP
385 depends on X86_EXTENDED_PLATFORM
387 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
388 subarchitectures. It is intended for a generic binary kernel.
389 if you select them all, kernel will probe it one by one. and will
392 # Alphabetically sorted list of Non standard 32 bit platforms
395 bool "NUMAQ (IBM/Sequent)"
396 depends on X86_32_NON_STANDARD
400 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
401 NUMA multiquad box. This changes the way that processors are
402 bootstrapped, and uses Clustered Logical APIC addressing mode instead
403 of Flat Logical. You will need a new lynxer.elf file to flash your
404 firmware with - send email to <Martin.Bligh@us.ibm.com>.
407 bool "SGI 320/540 (Visual Workstation)"
408 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
409 depends on X86_32_NON_STANDARD
411 The SGI Visual Workstation series is an IA32-based workstation
412 based on SGI systems chips with some legacy PC hardware attached.
414 Say Y here to create a kernel to run on the SGI 320 or 540.
416 A kernel compiled for the Visual Workstation will run on general
417 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
420 bool "Summit/EXA (IBM x440)"
421 depends on X86_32_NON_STANDARD
423 This option is needed for IBM systems that use the Summit/EXA chipset.
424 In particular, it is needed for the x440.
427 bool "Unisys ES7000 IA32 series"
428 depends on X86_32_NON_STANDARD && X86_BIGSMP
430 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
431 supposed to run on an IA32-based Unisys ES7000 system.
433 config SCHED_OMIT_FRAME_POINTER
435 prompt "Single-depth WCHAN output"
438 Calculate simpler /proc/<PID>/wchan values. If this option
439 is disabled then wchan values will recurse back to the
440 caller function. This provides more accurate wchan values,
441 at the expense of slightly more scheduling overhead.
443 If in doubt, say "Y".
445 menuconfig PARAVIRT_GUEST
446 bool "Paravirtualized guest support"
448 Say Y here to get to see options related to running Linux under
449 various hypervisors. This option alone does not add any kernel code.
451 If you say N, all options in this submenu will be skipped and disabled.
455 source "arch/x86/xen/Kconfig"
458 bool "VMI Guest support"
462 VMI provides a paravirtualized interface to the VMware ESX server
463 (it could be used by other hypervisors in theory too, but is not
464 at the moment), by linking the kernel to a GPL-ed ROM module
465 provided by the hypervisor.
468 bool "KVM paravirtualized clock"
470 select PARAVIRT_CLOCK
472 Turning on this option will allow you to run a paravirtualized clock
473 when running over the KVM hypervisor. Instead of relying on a PIT
474 (or probably other) emulation by the underlying device model, the host
475 provides the guest with timing infrastructure such as time of day, and
479 bool "KVM Guest support"
482 This option enables various optimizations for running under the KVM
485 source "arch/x86/lguest/Kconfig"
488 bool "Enable paravirtualization code"
490 This changes the kernel so it can modify itself when it is run
491 under a hypervisor, potentially improving performance significantly
492 over full virtualization. However, when run without a hypervisor
493 the kernel is theoretically slower and slightly larger.
495 config PARAVIRT_SPINLOCKS
496 bool "Paravirtualization layer for spinlocks"
497 depends on PARAVIRT && SMP && EXPERIMENTAL
499 Paravirtualized spinlocks allow a pvops backend to replace the
500 spinlock implementation with something virtualization-friendly
501 (for example, block the virtual CPU rather than spinning).
503 Unfortunately the downside is an up to 5% performance hit on
504 native kernels, with various workloads.
506 If you are unsure how to answer this question, answer N.
508 config PARAVIRT_CLOCK
514 config PARAVIRT_DEBUG
515 bool "paravirt-ops debugging"
516 depends on PARAVIRT && DEBUG_KERNEL
518 Enable to debug paravirt_ops internals. Specifically, BUG if
519 a paravirt_op is missing when it is called.
524 This option adds a kernel parameter 'memtest', which allows memtest
526 memtest=0, mean disabled; -- default
527 memtest=1, mean do 1 test pattern;
529 memtest=4, mean do 4 test patterns.
530 If you are unsure how to answer this question, answer N.
532 config X86_SUMMIT_NUMA
534 depends on X86_32 && NUMA && X86_32_NON_STANDARD
536 config X86_CYCLONE_TIMER
538 depends on X86_32_NON_STANDARD
540 source "arch/x86/Kconfig.cpu"
544 prompt "HPET Timer Support" if X86_32
546 Use the IA-PC HPET (High Precision Event Timer) to manage
547 time in preference to the PIT and RTC, if a HPET is
549 HPET is the next generation timer replacing legacy 8254s.
550 The HPET provides a stable time base on SMP
551 systems, unlike the TSC, but it is more expensive to access,
552 as it is off-chip. You can find the HPET spec at
553 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
555 You can safely choose Y here. However, HPET will only be
556 activated if the platform and the BIOS support this feature.
557 Otherwise the 8254 will be used for timing services.
559 Choose N to continue using the legacy 8254 timer.
561 config HPET_EMULATE_RTC
563 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
565 # Mark as embedded because too many people got it wrong.
566 # The code disables itself when not needed.
569 bool "Enable DMI scanning" if EMBEDDED
571 Enabled scanning of DMI to identify machine quirks. Say Y
572 here unless you have verified that your setup is not
573 affected by entries in the DMI blacklist. Required by PNP
577 bool "GART IOMMU support" if EMBEDDED
581 depends on X86_64 && PCI
583 Support for full DMA access of devices with 32bit memory access only
584 on systems with more than 3GB. This is usually needed for USB,
585 sound, many IDE/SATA chipsets and some other devices.
586 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
587 based hardware IOMMU and a software bounce buffer based IOMMU used
588 on Intel systems and as fallback.
589 The code is only active when needed (enough memory and limited
590 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
594 bool "IBM Calgary IOMMU support"
596 depends on X86_64 && PCI && EXPERIMENTAL
598 Support for hardware IOMMUs in IBM's xSeries x366 and x460
599 systems. Needed to run systems with more than 3GB of memory
600 properly with 32-bit PCI devices that do not support DAC
601 (Double Address Cycle). Calgary also supports bus level
602 isolation, where all DMAs pass through the IOMMU. This
603 prevents them from going anywhere except their intended
604 destination. This catches hard-to-find kernel bugs and
605 mis-behaving drivers and devices that do not use the DMA-API
606 properly to set up their DMA buffers. The IOMMU can be
607 turned off at boot time with the iommu=off parameter.
608 Normally the kernel will make the right choice by itself.
611 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
613 prompt "Should Calgary be enabled by default?"
614 depends on CALGARY_IOMMU
616 Should Calgary be enabled by default? if you choose 'y', Calgary
617 will be used (if it exists). If you choose 'n', Calgary will not be
618 used even if it exists. If you choose 'n' and would like to use
619 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
623 bool "AMD IOMMU support"
626 depends on X86_64 && PCI && ACPI
628 With this option you can enable support for AMD IOMMU hardware in
629 your system. An IOMMU is a hardware component which provides
630 remapping of DMA memory accesses from devices. With an AMD IOMMU you
631 can isolate the the DMA memory of different devices and protect the
632 system from misbehaving device drivers or hardware.
634 You can find out if your system has an AMD IOMMU if you look into
635 your BIOS for an option to enable it or if you have an IVRS ACPI
638 config AMD_IOMMU_STATS
639 bool "Export AMD IOMMU statistics to debugfs"
643 This option enables code in the AMD IOMMU driver to collect various
644 statistics about whats happening in the driver and exports that
645 information to userspace via debugfs.
648 # need this always selected by IOMMU for the VIA workaround
652 Support for software bounce buffers used on x86-64 systems
653 which don't have a hardware IOMMU (e.g. the current generation
654 of Intel's x86-64 CPUs). Using this PCI devices which can only
655 access 32-bits of memory can be used on systems with more than
656 3 GB of memory. If unsure, say Y.
659 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
662 def_bool (AMD_IOMMU || DMAR)
665 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
666 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
667 select CPUMASK_OFFSTACK
670 Configure maximum number of CPUS and NUMA Nodes for this architecture.
674 int "Maximum number of CPUs" if SMP && !MAXSMP
675 range 2 8 if SMP && X86_32 && !X86_BIGSMP
676 range 2 512 if SMP && !MAXSMP
678 default "4096" if MAXSMP
679 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
682 This allows you to specify the maximum number of CPUs which this
683 kernel will support. The maximum supported value is 512 and the
684 minimum value which makes sense is 2.
686 This is purely to save memory - each supported CPU adds
687 approximately eight kilobytes to the kernel image.
690 bool "SMT (Hyperthreading) scheduler support"
693 SMT scheduler support improves the CPU scheduler's decision making
694 when dealing with Intel Pentium 4 chips with HyperThreading at a
695 cost of slightly increased overhead in some places. If unsure say
700 prompt "Multi-core scheduler support"
703 Multi-core scheduler support improves the CPU scheduler's decision
704 making when dealing with multi-core CPU chips at a cost of slightly
705 increased overhead in some places. If unsure say N here.
707 source "kernel/Kconfig.preempt"
710 bool "Local APIC support on uniprocessors"
711 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
713 A local APIC (Advanced Programmable Interrupt Controller) is an
714 integrated interrupt controller in the CPU. If you have a single-CPU
715 system which has a processor with a local APIC, you can say Y here to
716 enable and use it. If you say Y here even though your machine doesn't
717 have a local APIC, then the kernel will still run with no slowdown at
718 all. The local APIC supports CPU-generated self-interrupts (timer,
719 performance counters), and the NMI watchdog which detects hard
723 bool "IO-APIC support on uniprocessors"
724 depends on X86_UP_APIC
726 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
727 SMP-capable replacement for PC-style interrupt controllers. Most
728 SMP systems and many recent uniprocessor systems have one.
730 If you have a single-CPU system with an IO-APIC, you can say Y here
731 to use it. If you say Y here even though your machine doesn't have
732 an IO-APIC, then the kernel will still run with no slowdown at all.
734 config X86_LOCAL_APIC
736 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
740 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
742 config X86_VISWS_APIC
744 depends on X86_32 && X86_VISWS
746 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
747 bool "Reroute for broken boot IRQs"
749 depends on X86_IO_APIC
751 This option enables a workaround that fixes a source of
752 spurious interrupts. This is recommended when threaded
753 interrupt handling is used on systems where the generation of
754 superfluous "boot interrupts" cannot be disabled.
756 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
757 entry in the chipset's IO-APIC is masked (as, e.g. the RT
758 kernel does during interrupt handling). On chipsets where this
759 boot IRQ generation cannot be disabled, this workaround keeps
760 the original IRQ line masked so that only the equivalent "boot
761 IRQ" is delivered to the CPUs. The workaround also tells the
762 kernel to set up the IRQ handler on the boot IRQ line. In this
763 way only one interrupt is delivered to the kernel. Otherwise
764 the spurious second interrupt may cause the kernel to bring
765 down (vital) interrupt lines.
767 Only affects "broken" chipsets. Interrupt sharing may be
768 increased on these systems.
771 bool "Machine Check Exception"
773 Machine Check Exception support allows the processor to notify the
774 kernel if it detects a problem (e.g. overheating, component failure).
775 The action the kernel takes depends on the severity of the problem,
776 ranging from a warning message on the console, to halting the machine.
777 Your processor must be a Pentium or newer to support this - check the
778 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
779 have a design flaw which leads to false MCE events - hence MCE is
780 disabled on all P5 processors, unless explicitly enabled with "mce"
781 as a boot argument. Similarly, if MCE is built in and creates a
782 problem on some new non-standard machine, you can boot with "nomce"
783 to disable it. MCE support simply ignores non-MCE processors like
784 the 386 and 486, so nearly everyone can say Y here.
787 depends on X86_32 && X86_MCE
788 bool "Use legacy machine check code (will go away)"
790 select X86_ANCIENT_MCE
792 Use the old i386 machine check code. This is merely intended for
793 testing in a transition period. Try this if you run into any machine
794 check related software problems, but report the problem to
795 linux-kernel. When in doubt say no.
800 default y if (!X86_OLD_MCE && X86_32) || X86_64
804 prompt "Intel MCE features"
805 depends on X86_NEW_MCE && X86_LOCAL_APIC
807 Additional support for intel specific MCE features such as
812 prompt "AMD MCE features"
813 depends on X86_NEW_MCE && X86_LOCAL_APIC
815 Additional support for AMD specific MCE features such as
816 the DRAM Error Threshold.
818 config X86_ANCIENT_MCE
821 prompt "Support for old Pentium 5 / WinChip machine checks"
823 Include support for machine check handling on old Pentium 5 or WinChip
824 systems. These typically need to be enabled explicitely on the command
827 config X86_MCE_THRESHOLD
828 depends on X86_MCE_AMD || X86_MCE_INTEL
832 config X86_MCE_INJECT
833 depends on X86_NEW_MCE
834 tristate "Machine check injector support"
836 Provide support for injecting machine checks for testing purposes.
837 If you don't know what a machine check is and you don't do kernel
838 QA it is safe to say n.
840 config X86_MCE_NONFATAL
841 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
842 depends on X86_OLD_MCE
844 Enabling this feature starts a timer that triggers every 5 seconds which
845 will look at the machine check registers to see if anything happened.
846 Non-fatal problems automatically get corrected (but still logged).
847 Disable this if you don't want to see these messages.
848 Seeing the messages this option prints out may be indicative of dying
849 or out-of-spec (ie, overclocked) hardware.
850 This option only does something on certain CPUs.
851 (AMD Athlon/Duron and Intel Pentium 4)
853 config X86_MCE_P4THERMAL
854 bool "check for P4 thermal throttling interrupt."
855 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
857 Enabling this feature will cause a message to be printed when the P4
858 enters thermal throttling.
860 config X86_THERMAL_VECTOR
862 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
865 bool "Enable VM86 support" if EMBEDDED
869 This option is required by programs like DOSEMU to run 16-bit legacy
870 code on X86 processors. It also may be needed by software like
871 XFree86 to initialize some video cards via BIOS. Disabling this
872 option saves about 6k.
875 tristate "Toshiba Laptop support"
878 This adds a driver to safely access the System Management Mode of
879 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
880 not work on models with a Phoenix BIOS. The System Management Mode
881 is used to set the BIOS and power saving options on Toshiba portables.
883 For information on utilities to make use of this driver see the
884 Toshiba Linux utilities web site at:
885 <http://www.buzzard.org.uk/toshiba/>.
887 Say Y if you intend to run this kernel on a Toshiba portable.
891 tristate "Dell laptop support"
893 This adds a driver to safely access the System Management Mode
894 of the CPU on the Dell Inspiron 8000. The System Management Mode
895 is used to read cpu temperature and cooling fan status and to
896 control the fans on the I8K portables.
898 This driver has been tested only on the Inspiron 8000 but it may
899 also work with other Dell laptops. You can force loading on other
900 models by passing the parameter `force=1' to the module. Use at
903 For information on utilities to make use of this driver see the
904 I8K Linux utilities web site at:
905 <http://people.debian.org/~dz/i8k/>
907 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
910 config X86_REBOOTFIXUPS
911 bool "Enable X86 board specific fixups for reboot"
914 This enables chipset and/or board specific fixups to be done
915 in order to get reboot to work correctly. This is only needed on
916 some combinations of hardware and BIOS. The symptom, for which
917 this config is intended, is when reboot ends with a stalled/hung
920 Currently, the only fixup is for the Geode machines using
921 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
923 Say Y if you want to enable the fixup. Currently, it's safe to
924 enable this option even if you don't need it.
928 tristate "/dev/cpu/microcode - microcode support"
931 If you say Y here, you will be able to update the microcode on
932 certain Intel and AMD processors. The Intel support is for the
933 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
934 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
935 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
936 You will obviously need the actual microcode binary data itself
937 which is not shipped with the Linux kernel.
939 This option selects the general module only, you need to select
940 at least one vendor specific module as well.
942 To compile this driver as a module, choose M here: the
943 module will be called microcode.
945 config MICROCODE_INTEL
946 bool "Intel microcode patch loading support"
951 This options enables microcode patch loading support for Intel
954 For latest news and information on obtaining all the required
955 Intel ingredients for this driver, check:
956 <http://www.urbanmyth.org/microcode/>.
959 bool "AMD microcode patch loading support"
963 If you select this option, microcode patch loading support for AMD
964 processors will be enabled.
966 config MICROCODE_OLD_INTERFACE
971 tristate "/dev/cpu/*/msr - Model-specific register support"
973 This device gives privileged processes access to the x86
974 Model-Specific Registers (MSRs). It is a character device with
975 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
976 MSR accesses are directed to a specific CPU on multi-processor
980 tristate "/dev/cpu/*/cpuid - CPU information support"
982 This device gives processes access to the x86 CPUID instruction to
983 be executed on a specific processor. It is a character device
984 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
988 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
990 If you select this option, this will provide various x86 CPUs
991 information through debugfs.
994 prompt "High Memory Support"
995 default HIGHMEM4G if !X86_NUMAQ
996 default HIGHMEM64G if X86_NUMAQ
1001 depends on !X86_NUMAQ
1003 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1004 However, the address space of 32-bit x86 processors is only 4
1005 Gigabytes large. That means that, if you have a large amount of
1006 physical memory, not all of it can be "permanently mapped" by the
1007 kernel. The physical memory that's not permanently mapped is called
1010 If you are compiling a kernel which will never run on a machine with
1011 more than 1 Gigabyte total physical RAM, answer "off" here (default
1012 choice and suitable for most users). This will result in a "3GB/1GB"
1013 split: 3GB are mapped so that each process sees a 3GB virtual memory
1014 space and the remaining part of the 4GB virtual memory space is used
1015 by the kernel to permanently map as much physical memory as
1018 If the machine has between 1 and 4 Gigabytes physical RAM, then
1021 If more than 4 Gigabytes is used then answer "64GB" here. This
1022 selection turns Intel PAE (Physical Address Extension) mode on.
1023 PAE implements 3-level paging on IA32 processors. PAE is fully
1024 supported by Linux, PAE mode is implemented on all recent Intel
1025 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1026 then the kernel will not boot on CPUs that don't support PAE!
1028 The actual amount of total physical memory will either be
1029 auto detected or can be forced by using a kernel command line option
1030 such as "mem=256M". (Try "man bootparam" or see the documentation of
1031 your boot loader (lilo or loadlin) about how to pass options to the
1032 kernel at boot time.)
1034 If unsure, say "off".
1038 depends on !X86_NUMAQ
1040 Select this if you have a 32-bit processor and between 1 and 4
1041 gigabytes of physical RAM.
1045 depends on !M386 && !M486
1048 Select this if you have a 32-bit processor and more than 4
1049 gigabytes of physical RAM.
1054 depends on EXPERIMENTAL
1055 prompt "Memory split" if EMBEDDED
1059 Select the desired split between kernel and user memory.
1061 If the address range available to the kernel is less than the
1062 physical memory installed, the remaining memory will be available
1063 as "high memory". Accessing high memory is a little more costly
1064 than low memory, as it needs to be mapped into the kernel first.
1065 Note that increasing the kernel address space limits the range
1066 available to user programs, making the address space there
1067 tighter. Selecting anything other than the default 3G/1G split
1068 will also likely make your kernel incompatible with binary-only
1071 If you are not absolutely sure what you are doing, leave this
1075 bool "3G/1G user/kernel split"
1076 config VMSPLIT_3G_OPT
1078 bool "3G/1G user/kernel split (for full 1G low memory)"
1080 bool "2G/2G user/kernel split"
1081 config VMSPLIT_2G_OPT
1083 bool "2G/2G user/kernel split (for full 2G low memory)"
1085 bool "1G/3G user/kernel split"
1090 default 0xB0000000 if VMSPLIT_3G_OPT
1091 default 0x80000000 if VMSPLIT_2G
1092 default 0x78000000 if VMSPLIT_2G_OPT
1093 default 0x40000000 if VMSPLIT_1G
1099 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1102 bool "PAE (Physical Address Extension) Support"
1103 depends on X86_32 && !HIGHMEM4G
1105 PAE is required for NX support, and furthermore enables
1106 larger swapspace support for non-overcommit purposes. It
1107 has the cost of more pagetable lookup overhead, and also
1108 consumes more pagetable space per process.
1110 config ARCH_PHYS_ADDR_T_64BIT
1111 def_bool X86_64 || X86_PAE
1113 config DIRECT_GBPAGES
1114 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1118 Allow the kernel linear mapping to use 1GB pages on CPUs that
1119 support it. This can improve the kernel's performance a tiny bit by
1120 reducing TLB pressure. If in doubt, say "Y".
1122 # Common NUMA Features
1124 bool "Numa Memory Allocation and Scheduler Support"
1126 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1127 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1129 Enable NUMA (Non Uniform Memory Access) support.
1131 The kernel will try to allocate memory used by a CPU on the
1132 local memory controller of the CPU and add some more
1133 NUMA awareness to the kernel.
1135 For 64-bit this is recommended if the system is Intel Core i7
1136 (or later), AMD Opteron, or EM64T NUMA.
1138 For 32-bit this is only needed on (rare) 32-bit-only platforms
1139 that support NUMA topologies, such as NUMAQ / Summit, or if you
1140 boot a 32-bit kernel on a 64-bit NUMA platform.
1142 Otherwise, you should say N.
1144 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1145 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1149 prompt "Old style AMD Opteron NUMA detection"
1150 depends on X86_64 && NUMA && PCI
1152 Enable K8 NUMA node topology detection. You should say Y here if
1153 you have a multi processor AMD K8 system. This uses an old
1154 method to read the NUMA configuration directly from the builtin
1155 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1156 instead, which also takes priority if both are compiled in.
1158 config X86_64_ACPI_NUMA
1160 prompt "ACPI NUMA detection"
1161 depends on X86_64 && NUMA && ACPI && PCI
1164 Enable ACPI SRAT based node topology detection.
1166 # Some NUMA nodes have memory ranges that span
1167 # other nodes. Even though a pfn is valid and
1168 # between a node's start and end pfns, it may not
1169 # reside on that node. See memmap_init_zone()
1171 config NODES_SPAN_OTHER_NODES
1173 depends on X86_64_ACPI_NUMA
1176 bool "NUMA emulation"
1177 depends on X86_64 && NUMA
1179 Enable NUMA emulation. A flat machine will be split
1180 into virtual nodes when booted with "numa=fake=N", where N is the
1181 number of nodes. This is only useful for debugging.
1184 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1186 default "9" if MAXSMP
1187 default "6" if X86_64
1188 default "4" if X86_NUMAQ
1190 depends on NEED_MULTIPLE_NODES
1192 Specify the maximum number of NUMA Nodes available on the target
1193 system. Increases memory reserved to accommodate various tables.
1195 config HAVE_ARCH_BOOTMEM
1197 depends on X86_32 && NUMA
1199 config ARCH_HAVE_MEMORY_PRESENT
1201 depends on X86_32 && DISCONTIGMEM
1203 config NEED_NODE_MEMMAP_SIZE
1205 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1207 config HAVE_ARCH_ALLOC_REMAP
1209 depends on X86_32 && NUMA
1211 config ARCH_FLATMEM_ENABLE
1213 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1215 config ARCH_DISCONTIGMEM_ENABLE
1217 depends on NUMA && X86_32
1219 config ARCH_DISCONTIGMEM_DEFAULT
1221 depends on NUMA && X86_32
1223 config ARCH_SPARSEMEM_DEFAULT
1227 config ARCH_SPARSEMEM_ENABLE
1229 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1230 select SPARSEMEM_STATIC if X86_32
1231 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1233 config ARCH_SELECT_MEMORY_MODEL
1235 depends on ARCH_SPARSEMEM_ENABLE
1237 config ARCH_MEMORY_PROBE
1239 depends on MEMORY_HOTPLUG
1244 bool "Allocate 3rd-level pagetables from highmem"
1245 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1247 The VM uses one page table entry for each page of physical memory.
1248 For systems with a lot of RAM, this can be wasteful of precious
1249 low memory. Setting this option will put user-space page table
1250 entries in high memory.
1252 config X86_CHECK_BIOS_CORRUPTION
1253 bool "Check for low memory corruption"
1255 Periodically check for memory corruption in low memory, which
1256 is suspected to be caused by BIOS. Even when enabled in the
1257 configuration, it is disabled at runtime. Enable it by
1258 setting "memory_corruption_check=1" on the kernel command
1259 line. By default it scans the low 64k of memory every 60
1260 seconds; see the memory_corruption_check_size and
1261 memory_corruption_check_period parameters in
1262 Documentation/kernel-parameters.txt to adjust this.
1264 When enabled with the default parameters, this option has
1265 almost no overhead, as it reserves a relatively small amount
1266 of memory and scans it infrequently. It both detects corruption
1267 and prevents it from affecting the running system.
1269 It is, however, intended as a diagnostic tool; if repeatable
1270 BIOS-originated corruption always affects the same memory,
1271 you can use memmap= to prevent the kernel from using that
1274 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1275 bool "Set the default setting of memory_corruption_check"
1276 depends on X86_CHECK_BIOS_CORRUPTION
1279 Set whether the default state of memory_corruption_check is
1282 config X86_RESERVE_LOW_64K
1283 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1286 Reserve the first 64K of physical RAM on BIOSes that are known
1287 to potentially corrupt that memory range. A numbers of BIOSes are
1288 known to utilize this area during suspend/resume, so it must not
1289 be used by the kernel.
1291 Set this to N if you are absolutely sure that you trust the BIOS
1292 to get all its memory reservations and usages right.
1294 If you have doubts about the BIOS (e.g. suspend/resume does not
1295 work or there's kernel crashes after certain hardware hotplug
1296 events) and it's not AMI or Phoenix, then you might want to enable
1297 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1298 corruption patterns.
1302 config MATH_EMULATION
1304 prompt "Math emulation" if X86_32
1306 Linux can emulate a math coprocessor (used for floating point
1307 operations) if you don't have one. 486DX and Pentium processors have
1308 a math coprocessor built in, 486SX and 386 do not, unless you added
1309 a 487DX or 387, respectively. (The messages during boot time can
1310 give you some hints here ["man dmesg"].) Everyone needs either a
1311 coprocessor or this emulation.
1313 If you don't have a math coprocessor, you need to say Y here; if you
1314 say Y here even though you have a coprocessor, the coprocessor will
1315 be used nevertheless. (This behavior can be changed with the kernel
1316 command line option "no387", which comes handy if your coprocessor
1317 is broken. Try "man bootparam" or see the documentation of your boot
1318 loader (lilo or loadlin) about how to pass options to the kernel at
1319 boot time.) This means that it is a good idea to say Y here if you
1320 intend to use this kernel on different machines.
1322 More information about the internals of the Linux math coprocessor
1323 emulation can be found in <file:arch/x86/math-emu/README>.
1325 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1326 kernel, it won't hurt.
1329 bool "MTRR (Memory Type Range Register) support"
1331 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1332 the Memory Type Range Registers (MTRRs) may be used to control
1333 processor access to memory ranges. This is most useful if you have
1334 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1335 allows bus write transfers to be combined into a larger transfer
1336 before bursting over the PCI/AGP bus. This can increase performance
1337 of image write operations 2.5 times or more. Saying Y here creates a
1338 /proc/mtrr file which may be used to manipulate your processor's
1339 MTRRs. Typically the X server should use this.
1341 This code has a reasonably generic interface so that similar
1342 control registers on other processors can be easily supported
1345 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1346 Registers (ARRs) which provide a similar functionality to MTRRs. For
1347 these, the ARRs are used to emulate the MTRRs.
1348 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1349 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1350 write-combining. All of these processors are supported by this code
1351 and it makes sense to say Y here if you have one of them.
1353 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1354 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1355 can lead to all sorts of problems, so it's good to say Y here.
1357 You can safely say Y even if your machine doesn't have MTRRs, you'll
1358 just add about 9 KB to your kernel.
1360 See <file:Documentation/x86/mtrr.txt> for more information.
1362 config MTRR_SANITIZER
1364 prompt "MTRR cleanup support"
1367 Convert MTRR layout from continuous to discrete, so X drivers can
1368 add writeback entries.
1370 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1371 The largest mtrr entry size for a continuous block can be set with
1376 config MTRR_SANITIZER_ENABLE_DEFAULT
1377 int "MTRR cleanup enable value (0-1)"
1380 depends on MTRR_SANITIZER
1382 Enable mtrr cleanup default value
1384 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1385 int "MTRR cleanup spare reg num (0-7)"
1388 depends on MTRR_SANITIZER
1390 mtrr cleanup spare entries default, it can be changed via
1391 mtrr_spare_reg_nr=N on the kernel command line.
1395 prompt "x86 PAT support"
1398 Use PAT attributes to setup page level cache control.
1400 PATs are the modern equivalents of MTRRs and are much more
1401 flexible than MTRRs.
1403 Say N here if you see bootup problems (boot crash, boot hang,
1404 spontaneous reboots) or a non-working video driver.
1409 bool "EFI runtime service support"
1412 This enables the kernel to use EFI runtime services that are
1413 available (such as the EFI variable services).
1415 This option is only useful on systems that have EFI firmware.
1416 In addition, you should use the latest ELILO loader available
1417 at <http://elilo.sourceforge.net> in order to take advantage
1418 of EFI runtime services. However, even with this option, the
1419 resultant kernel should continue to boot on existing non-EFI
1424 prompt "Enable seccomp to safely compute untrusted bytecode"
1426 This kernel feature is useful for number crunching applications
1427 that may need to compute untrusted bytecode during their
1428 execution. By using pipes or other transports made available to
1429 the process as file descriptors supporting the read/write
1430 syscalls, it's possible to isolate those applications in
1431 their own address space using seccomp. Once seccomp is
1432 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1433 and the task is only allowed to execute a few safe syscalls
1434 defined by each seccomp mode.
1436 If unsure, say Y. Only embedded should say N here.
1438 config CC_STACKPROTECTOR_ALL
1441 config CC_STACKPROTECTOR
1442 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1443 select CC_STACKPROTECTOR_ALL
1445 This option turns on the -fstack-protector GCC feature. This
1446 feature puts, at the beginning of functions, a canary value on
1447 the stack just before the return address, and validates
1448 the value just before actually returning. Stack based buffer
1449 overflows (that need to overwrite this return address) now also
1450 overwrite the canary, which gets detected and the attack is then
1451 neutralized via a kernel panic.
1453 This feature requires gcc version 4.2 or above, or a distribution
1454 gcc with the feature backported. Older versions are automatically
1455 detected and for those versions, this configuration option is
1456 ignored. (and a warning is printed during bootup)
1458 source kernel/Kconfig.hz
1461 bool "kexec system call"
1463 kexec is a system call that implements the ability to shutdown your
1464 current kernel, and to start another kernel. It is like a reboot
1465 but it is independent of the system firmware. And like a reboot
1466 you can start any kernel with it, not just Linux.
1468 The name comes from the similarity to the exec system call.
1470 It is an ongoing process to be certain the hardware in a machine
1471 is properly shutdown, so do not be surprised if this code does not
1472 initially work for you. It may help to enable device hotplugging
1473 support. As of this writing the exact hardware interface is
1474 strongly in flux, so no good recommendation can be made.
1477 bool "kernel crash dumps"
1478 depends on X86_64 || (X86_32 && HIGHMEM)
1480 Generate crash dump after being started by kexec.
1481 This should be normally only set in special crash dump kernels
1482 which are loaded in the main kernel with kexec-tools into
1483 a specially reserved region and then later executed after
1484 a crash by kdump/kexec. The crash dump kernel must be compiled
1485 to a memory address not used by the main kernel or BIOS using
1486 PHYSICAL_START, or it must be built as a relocatable image
1487 (CONFIG_RELOCATABLE=y).
1488 For more details see Documentation/kdump/kdump.txt
1491 bool "kexec jump (EXPERIMENTAL)"
1492 depends on EXPERIMENTAL
1493 depends on KEXEC && HIBERNATION
1495 Jump between original kernel and kexeced kernel and invoke
1496 code in physical address mode via KEXEC
1498 config PHYSICAL_START
1499 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1500 default "0x1000000" if X86_NUMAQ
1501 default "0x200000" if X86_64
1504 This gives the physical address where the kernel is loaded.
1506 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1507 bzImage will decompress itself to above physical address and
1508 run from there. Otherwise, bzImage will run from the address where
1509 it has been loaded by the boot loader and will ignore above physical
1512 In normal kdump cases one does not have to set/change this option
1513 as now bzImage can be compiled as a completely relocatable image
1514 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1515 address. This option is mainly useful for the folks who don't want
1516 to use a bzImage for capturing the crash dump and want to use a
1517 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1518 to be specifically compiled to run from a specific memory area
1519 (normally a reserved region) and this option comes handy.
1521 So if you are using bzImage for capturing the crash dump, leave
1522 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1523 Otherwise if you plan to use vmlinux for capturing the crash dump
1524 change this value to start of the reserved region (Typically 16MB
1525 0x1000000). In other words, it can be set based on the "X" value as
1526 specified in the "crashkernel=YM@XM" command line boot parameter
1527 passed to the panic-ed kernel. Typically this parameter is set as
1528 crashkernel=64M@16M. Please take a look at
1529 Documentation/kdump/kdump.txt for more details about crash dumps.
1531 Usage of bzImage for capturing the crash dump is recommended as
1532 one does not have to build two kernels. Same kernel can be used
1533 as production kernel and capture kernel. Above option should have
1534 gone away after relocatable bzImage support is introduced. But it
1535 is present because there are users out there who continue to use
1536 vmlinux for dump capture. This option should go away down the
1539 Don't change this unless you know what you are doing.
1542 bool "Build a relocatable kernel (EXPERIMENTAL)"
1543 depends on EXPERIMENTAL
1545 This builds a kernel image that retains relocation information
1546 so it can be loaded someplace besides the default 1MB.
1547 The relocations tend to make the kernel binary about 10% larger,
1548 but are discarded at runtime.
1550 One use is for the kexec on panic case where the recovery kernel
1551 must live at a different physical address than the primary
1554 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1555 it has been loaded at and the compile time physical address
1556 (CONFIG_PHYSICAL_START) is ignored.
1558 config PHYSICAL_ALIGN
1560 prompt "Alignment value to which kernel should be aligned" if X86_32
1561 default "0x100000" if X86_32
1562 default "0x200000" if X86_64
1563 range 0x2000 0x400000
1565 This value puts the alignment restrictions on physical address
1566 where kernel is loaded and run from. Kernel is compiled for an
1567 address which meets above alignment restriction.
1569 If bootloader loads the kernel at a non-aligned address and
1570 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1571 address aligned to above value and run from there.
1573 If bootloader loads the kernel at a non-aligned address and
1574 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1575 load address and decompress itself to the address it has been
1576 compiled for and run from there. The address for which kernel is
1577 compiled already meets above alignment restrictions. Hence the
1578 end result is that kernel runs from a physical address meeting
1579 above alignment restrictions.
1581 Don't change this unless you know what you are doing.
1584 bool "Support for hot-pluggable CPUs"
1585 depends on SMP && HOTPLUG
1587 Say Y here to allow turning CPUs off and on. CPUs can be
1588 controlled through /sys/devices/system/cpu.
1589 ( Note: power management support will enable this option
1590 automatically on SMP systems. )
1591 Say N if you want to disable CPU hotplug.
1595 prompt "Compat VDSO support"
1596 depends on X86_32 || IA32_EMULATION
1598 Map the 32-bit VDSO to the predictable old-style address too.
1600 Say N here if you are running a sufficiently recent glibc
1601 version (2.3.3 or later), to remove the high-mapped
1602 VDSO mapping and to exclusively use the randomized VDSO.
1607 bool "Built-in kernel command line"
1610 Allow for specifying boot arguments to the kernel at
1611 build time. On some systems (e.g. embedded ones), it is
1612 necessary or convenient to provide some or all of the
1613 kernel boot arguments with the kernel itself (that is,
1614 to not rely on the boot loader to provide them.)
1616 To compile command line arguments into the kernel,
1617 set this option to 'Y', then fill in the
1618 the boot arguments in CONFIG_CMDLINE.
1620 Systems with fully functional boot loaders (i.e. non-embedded)
1621 should leave this option set to 'N'.
1624 string "Built-in kernel command string"
1625 depends on CMDLINE_BOOL
1628 Enter arguments here that should be compiled into the kernel
1629 image and used at boot time. If the boot loader provides a
1630 command line at boot time, it is appended to this string to
1631 form the full kernel command line, when the system boots.
1633 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1634 change this behavior.
1636 In most cases, the command line (whether built-in or provided
1637 by the boot loader) should specify the device for the root
1640 config CMDLINE_OVERRIDE
1641 bool "Built-in command line overrides boot loader arguments"
1643 depends on CMDLINE_BOOL
1645 Set this option to 'Y' to have the kernel ignore the boot loader
1646 command line, and use ONLY the built-in command line.
1648 This is used to work around broken boot loaders. This should
1649 be set to 'N' under normal conditions.
1653 config ARCH_ENABLE_MEMORY_HOTPLUG
1655 depends on X86_64 || (X86_32 && HIGHMEM)
1657 config ARCH_ENABLE_MEMORY_HOTREMOVE
1659 depends on MEMORY_HOTPLUG
1661 config HAVE_ARCH_EARLY_PFN_TO_NID
1665 menu "Power management and ACPI options"
1667 config ARCH_HIBERNATION_HEADER
1669 depends on X86_64 && HIBERNATION
1671 source "kernel/power/Kconfig"
1673 source "drivers/acpi/Kconfig"
1678 depends on APM || APM_MODULE
1681 tristate "APM (Advanced Power Management) BIOS support"
1682 depends on X86_32 && PM_SLEEP
1684 APM is a BIOS specification for saving power using several different
1685 techniques. This is mostly useful for battery powered laptops with
1686 APM compliant BIOSes. If you say Y here, the system time will be
1687 reset after a RESUME operation, the /proc/apm device will provide
1688 battery status information, and user-space programs will receive
1689 notification of APM "events" (e.g. battery status change).
1691 If you select "Y" here, you can disable actual use of the APM
1692 BIOS by passing the "apm=off" option to the kernel at boot time.
1694 Note that the APM support is almost completely disabled for
1695 machines with more than one CPU.
1697 In order to use APM, you will need supporting software. For location
1698 and more information, read <file:Documentation/power/pm.txt> and the
1699 Battery Powered Linux mini-HOWTO, available from
1700 <http://www.tldp.org/docs.html#howto>.
1702 This driver does not spin down disk drives (see the hdparm(8)
1703 manpage ("man 8 hdparm") for that), and it doesn't turn off
1704 VESA-compliant "green" monitors.
1706 This driver does not support the TI 4000M TravelMate and the ACER
1707 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1708 desktop machines also don't have compliant BIOSes, and this driver
1709 may cause those machines to panic during the boot phase.
1711 Generally, if you don't have a battery in your machine, there isn't
1712 much point in using this driver and you should say N. If you get
1713 random kernel OOPSes or reboots that don't seem to be related to
1714 anything, try disabling/enabling this option (or disabling/enabling
1717 Some other things you should try when experiencing seemingly random,
1720 1) make sure that you have enough swap space and that it is
1722 2) pass the "no-hlt" option to the kernel
1723 3) switch on floating point emulation in the kernel and pass
1724 the "no387" option to the kernel
1725 4) pass the "floppy=nodma" option to the kernel
1726 5) pass the "mem=4M" option to the kernel (thereby disabling
1727 all but the first 4 MB of RAM)
1728 6) make sure that the CPU is not over clocked.
1729 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1730 8) disable the cache from your BIOS settings
1731 9) install a fan for the video card or exchange video RAM
1732 10) install a better fan for the CPU
1733 11) exchange RAM chips
1734 12) exchange the motherboard.
1736 To compile this driver as a module, choose M here: the
1737 module will be called apm.
1741 config APM_IGNORE_USER_SUSPEND
1742 bool "Ignore USER SUSPEND"
1744 This option will ignore USER SUSPEND requests. On machines with a
1745 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1746 series notebooks, it is necessary to say Y because of a BIOS bug.
1748 config APM_DO_ENABLE
1749 bool "Enable PM at boot time"
1751 Enable APM features at boot time. From page 36 of the APM BIOS
1752 specification: "When disabled, the APM BIOS does not automatically
1753 power manage devices, enter the Standby State, enter the Suspend
1754 State, or take power saving steps in response to CPU Idle calls."
1755 This driver will make CPU Idle calls when Linux is idle (unless this
1756 feature is turned off -- see "Do CPU IDLE calls", below). This
1757 should always save battery power, but more complicated APM features
1758 will be dependent on your BIOS implementation. You may need to turn
1759 this option off if your computer hangs at boot time when using APM
1760 support, or if it beeps continuously instead of suspending. Turn
1761 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1762 T400CDT. This is off by default since most machines do fine without
1766 bool "Make CPU Idle calls when idle"
1768 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1769 On some machines, this can activate improved power savings, such as
1770 a slowed CPU clock rate, when the machine is idle. These idle calls
1771 are made after the idle loop has run for some length of time (e.g.,
1772 333 mS). On some machines, this will cause a hang at boot time or
1773 whenever the CPU becomes idle. (On machines with more than one CPU,
1774 this option does nothing.)
1776 config APM_DISPLAY_BLANK
1777 bool "Enable console blanking using APM"
1779 Enable console blanking using the APM. Some laptops can use this to
1780 turn off the LCD backlight when the screen blanker of the Linux
1781 virtual console blanks the screen. Note that this is only used by
1782 the virtual console screen blanker, and won't turn off the backlight
1783 when using the X Window system. This also doesn't have anything to
1784 do with your VESA-compliant power-saving monitor. Further, this
1785 option doesn't work for all laptops -- it might not turn off your
1786 backlight at all, or it might print a lot of errors to the console,
1787 especially if you are using gpm.
1789 config APM_ALLOW_INTS
1790 bool "Allow interrupts during APM BIOS calls"
1792 Normally we disable external interrupts while we are making calls to
1793 the APM BIOS as a measure to lessen the effects of a badly behaving
1794 BIOS implementation. The BIOS should reenable interrupts if it
1795 needs to. Unfortunately, some BIOSes do not -- especially those in
1796 many of the newer IBM Thinkpads. If you experience hangs when you
1797 suspend, try setting this to Y. Otherwise, say N.
1801 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1803 source "drivers/cpuidle/Kconfig"
1805 source "drivers/idle/Kconfig"
1810 menu "Bus options (PCI etc.)"
1815 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1817 Find out whether you have a PCI motherboard. PCI is the name of a
1818 bus system, i.e. the way the CPU talks to the other stuff inside
1819 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1820 VESA. If you have PCI, say Y, otherwise N.
1823 prompt "PCI access mode"
1824 depends on X86_32 && PCI
1827 On PCI systems, the BIOS can be used to detect the PCI devices and
1828 determine their configuration. However, some old PCI motherboards
1829 have BIOS bugs and may crash if this is done. Also, some embedded
1830 PCI-based systems don't have any BIOS at all. Linux can also try to
1831 detect the PCI hardware directly without using the BIOS.
1833 With this option, you can specify how Linux should detect the
1834 PCI devices. If you choose "BIOS", the BIOS will be used,
1835 if you choose "Direct", the BIOS won't be used, and if you
1836 choose "MMConfig", then PCI Express MMCONFIG will be used.
1837 If you choose "Any", the kernel will try MMCONFIG, then the
1838 direct access method and falls back to the BIOS if that doesn't
1839 work. If unsure, go with the default, which is "Any".
1844 config PCI_GOMMCONFIG
1861 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1863 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1866 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1870 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1874 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1881 bool "Support mmconfig PCI config space access"
1882 depends on X86_64 && PCI && ACPI
1885 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1886 depends on PCI_MSI && ACPI && EXPERIMENTAL
1888 DMA remapping (DMAR) devices support enables independent address
1889 translations for Direct Memory Access (DMA) from devices.
1890 These DMA remapping devices are reported via ACPI tables
1891 and include PCI device scope covered by these DMA
1894 config DMAR_DEFAULT_ON
1896 prompt "Enable DMA Remapping Devices by default"
1899 Selecting this option will enable a DMAR device at boot time if
1900 one is found. If this option is not selected, DMAR support can
1901 be enabled by passing intel_iommu=on to the kernel. It is
1902 recommended you say N here while the DMAR code remains
1907 prompt "Support for Graphics workaround"
1910 Current Graphics drivers tend to use physical address
1911 for DMA and avoid using DMA APIs. Setting this config
1912 option permits the IOMMU driver to set a unity map for
1913 all the OS-visible memory. Hence the driver can continue
1914 to use physical addresses for DMA.
1916 config DMAR_FLOPPY_WA
1920 Floppy disk drivers are know to bypass DMA API calls
1921 thereby failing to work when IOMMU is enabled. This
1922 workaround will setup a 1:1 mapping for the first
1923 16M to make floppy (an ISA device) work.
1926 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1927 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1929 Supports Interrupt remapping for IO-APIC and MSI devices.
1930 To use x2apic mode in the CPU's which support x2APIC enhancements or
1931 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1933 source "drivers/pci/pcie/Kconfig"
1935 source "drivers/pci/Kconfig"
1937 # x86_64 have no ISA slots, but do have ISA-style DMA.
1946 Find out whether you have ISA slots on your motherboard. ISA is the
1947 name of a bus system, i.e. the way the CPU talks to the other stuff
1948 inside your box. Other bus systems are PCI, EISA, MicroChannel
1949 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1950 newer boards don't support it. If you have ISA, say Y, otherwise N.
1956 The Extended Industry Standard Architecture (EISA) bus was
1957 developed as an open alternative to the IBM MicroChannel bus.
1959 The EISA bus provided some of the features of the IBM MicroChannel
1960 bus while maintaining backward compatibility with cards made for
1961 the older ISA bus. The EISA bus saw limited use between 1988 and
1962 1995 when it was made obsolete by the PCI bus.
1964 Say Y here if you are building a kernel for an EISA-based machine.
1968 source "drivers/eisa/Kconfig"
1973 MicroChannel Architecture is found in some IBM PS/2 machines and
1974 laptops. It is a bus system similar to PCI or ISA. See
1975 <file:Documentation/mca.txt> (and especially the web page given
1976 there) before attempting to build an MCA bus kernel.
1978 source "drivers/mca/Kconfig"
1981 tristate "NatSemi SCx200 support"
1983 This provides basic support for National Semiconductor's
1984 (now AMD's) Geode processors. The driver probes for the
1985 PCI-IDs of several on-chip devices, so its a good dependency
1986 for other scx200_* drivers.
1988 If compiled as a module, the driver is named scx200.
1990 config SCx200HR_TIMER
1991 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1992 depends on SCx200 && GENERIC_TIME
1995 This driver provides a clocksource built upon the on-chip
1996 27MHz high-resolution timer. Its also a workaround for
1997 NSC Geode SC-1100's buggy TSC, which loses time when the
1998 processor goes idle (as is done by the scheduler). The
1999 other workaround is idle=poll boot option.
2001 config GEODE_MFGPT_TIMER
2003 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2004 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2006 This driver provides a clock event source based on the MFGPT
2007 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2008 MFGPTs have a better resolution and max interval than the
2009 generic PIT, and are suitable for use as high-res timers.
2012 bool "One Laptop Per Child support"
2015 Add support for detecting the unique features of the OLPC
2022 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2024 source "drivers/pcmcia/Kconfig"
2026 source "drivers/pci/hotplug/Kconfig"
2031 menu "Executable file formats / Emulations"
2033 source "fs/Kconfig.binfmt"
2035 config IA32_EMULATION
2036 bool "IA32 Emulation"
2038 select COMPAT_BINFMT_ELF
2040 Include code to run 32-bit programs under a 64-bit kernel. You should
2041 likely turn this on, unless you're 100% sure that you don't have any
2042 32-bit programs left.
2045 tristate "IA32 a.out support"
2046 depends on IA32_EMULATION
2048 Support old a.out binaries in the 32bit emulation.
2052 depends on IA32_EMULATION
2054 config COMPAT_FOR_U64_ALIGNMENT
2058 config SYSVIPC_COMPAT
2060 depends on COMPAT && SYSVIPC
2065 config HAVE_ATOMIC_IOMAP
2069 source "net/Kconfig"
2071 source "drivers/Kconfig"
2073 source "drivers/firmware/Kconfig"
2077 source "arch/x86/Kconfig.debug"
2079 source "security/Kconfig"
2081 source "crypto/Kconfig"
2083 source "arch/x86/kvm/Kconfig"
2085 source "lib/Kconfig"
projects / linux-2.6 / blob