2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PERF_COUNTERS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_FTRACE_SYSCALLS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_DMA_API_DEBUG
49 select HAVE_KERNEL_GZIP
50 select HAVE_KERNEL_BZIP2
51 select HAVE_KERNEL_LZMA
52 select HAVE_ARCH_KMEMCHECK
56 default "elf32-i386" if X86_32
57 default "elf64-x86-64" if X86_64
61 default "arch/x86/configs/i386_defconfig" if X86_32
62 default "arch/x86/configs/x86_64_defconfig" if X86_64
67 config GENERIC_CMOS_UPDATE
70 config CLOCKSOURCE_WATCHDOG
73 config GENERIC_CLOCKEVENTS
76 config GENERIC_CLOCKEVENTS_BROADCAST
78 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
80 config LOCKDEP_SUPPORT
83 config STACKTRACE_SUPPORT
86 config HAVE_LATENCYTOP_SUPPORT
89 config FAST_CMPXCHG_LOCAL
102 config GENERIC_ISA_DMA
111 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
113 config GENERIC_BUG_RELATIVE_POINTERS
116 config GENERIC_HWEIGHT
122 config ARCH_MAY_HAVE_PC_FDC
125 config RWSEM_GENERIC_SPINLOCK
128 config RWSEM_XCHGADD_ALGORITHM
131 config ARCH_HAS_CPU_IDLE_WAIT
134 config GENERIC_CALIBRATE_DELAY
137 config GENERIC_TIME_VSYSCALL
141 config ARCH_HAS_CPU_RELAX
144 config ARCH_HAS_DEFAULT_IDLE
147 config ARCH_HAS_CACHE_LINE_SIZE
150 config HAVE_SETUP_PER_CPU_AREA
153 config HAVE_DYNAMIC_PER_CPU_AREA
156 config HAVE_CPUMASK_OF_CPU_MAP
159 config ARCH_HIBERNATION_POSSIBLE
162 config ARCH_SUSPEND_POSSIBLE
169 config ARCH_POPULATES_NODE_MAP
176 config ARCH_SUPPORTS_OPTIMIZED_INLINING
179 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
182 config HAVE_INTEL_TXT
184 depends on EXPERIMENTAL && DMAR && ACPI
186 # Use the generic interrupt handling code in kernel/irq/:
187 config GENERIC_HARDIRQS
191 config GENERIC_HARDIRQS_NO__DO_IRQ
194 config GENERIC_IRQ_PROBE
198 config GENERIC_PENDING_IRQ
200 depends on GENERIC_HARDIRQS && SMP
203 config USE_GENERIC_SMP_HELPERS
209 depends on X86_32 && SMP
213 depends on X86_64 && SMP
220 config X86_TRAMPOLINE
222 depends on SMP || (64BIT && ACPI_SLEEP)
225 config X86_32_LAZY_GS
227 depends on X86_32 && !CC_STACKPROTECTOR
231 source "init/Kconfig"
232 source "kernel/Kconfig.freezer"
234 menu "Processor type and features"
236 source "kernel/time/Kconfig"
239 bool "Symmetric multi-processing support"
241 This enables support for systems with more than one CPU. If you have
242 a system with only one CPU, like most personal computers, say N. If
243 you have a system with more than one CPU, say Y.
245 If you say N here, the kernel will run on single and multiprocessor
246 machines, but will use only one CPU of a multiprocessor machine. If
247 you say Y here, the kernel will run on many, but not all,
248 singleprocessor machines. On a singleprocessor machine, the kernel
249 will run faster if you say N here.
251 Note that if you say Y here and choose architecture "586" or
252 "Pentium" under "Processor family", the kernel will not work on 486
253 architectures. Similarly, multiprocessor kernels for the "PPro"
254 architecture may not work on all Pentium based boards.
256 People using multiprocessor machines who say Y here should also say
257 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
258 Management" code will be disabled if you say Y here.
260 See also <file:Documentation/i386/IO-APIC.txt>,
261 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
262 <http://www.tldp.org/docs.html#howto>.
264 If you don't know what to do here, say N.
267 bool "Support x2apic"
268 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
270 This enables x2apic support on CPUs that have this feature.
272 This allows 32-bit apic IDs (so it can support very large systems),
273 and accesses the local apic via MSRs not via mmio.
275 If you don't know what to do here, say N.
278 bool "Support sparse irq numbering"
279 depends on PCI_MSI || HT_IRQ
281 This enables support for sparse irqs. This is useful for distro
282 kernels that want to define a high CONFIG_NR_CPUS value but still
283 want to have low kernel memory footprint on smaller machines.
285 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
286 out the irq_desc[] array in a more NUMA-friendly way. )
288 If you don't know what to do here, say N.
292 depends on SPARSE_IRQ && NUMA
295 bool "Enable MPS table" if ACPI
297 depends on X86_LOCAL_APIC
299 For old smp systems that do not have proper acpi support. Newer systems
300 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
303 bool "Support for big SMP systems with more than 8 CPUs"
304 depends on X86_32 && SMP
306 This option is needed for the systems that have more than 8 CPUs
309 config X86_EXTENDED_PLATFORM
310 bool "Support for extended (non-PC) x86 platforms"
313 If you disable this option then the kernel will only support
314 standard PC platforms. (which covers the vast majority of
317 If you enable this option then you'll be able to select support
318 for the following (non-PC) 32 bit x86 platforms:
322 SGI 320/540 (Visual Workstation)
323 Summit/EXA (IBM x440)
324 Unisys ES7000 IA32 series
326 If you have one of these systems, or if you want to build a
327 generic distribution kernel, say Y here - otherwise say N.
331 config X86_EXTENDED_PLATFORM
332 bool "Support for extended (non-PC) x86 platforms"
335 If you disable this option then the kernel will only support
336 standard PC platforms. (which covers the vast majority of
339 If you enable this option then you'll be able to select support
340 for the following (non-PC) 64 bit x86 platforms:
344 If you have one of these systems, or if you want to build a
345 generic distribution kernel, say Y here - otherwise say N.
347 # This is an alphabetically sorted list of 64 bit extended platforms
348 # Please maintain the alphabetic order if and when there are additions
353 depends on X86_64 && PCI
354 depends on X86_EXTENDED_PLATFORM
356 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
357 supposed to run on these EM64T-based machines. Only choose this option
358 if you have one of these machines.
361 bool "SGI Ultraviolet"
363 depends on X86_EXTENDED_PLATFORM
365 depends on X86_X2APIC
367 This option is needed in order to support SGI Ultraviolet systems.
368 If you don't have one of these, you should say N here.
370 # Following is an alphabetically sorted list of 32 bit extended platforms
371 # Please maintain the alphabetic order if and when there are additions
376 depends on X86_EXTENDED_PLATFORM
378 Select this for an AMD Elan processor.
380 Do not use this option for K6/Athlon/Opteron processors!
382 If unsure, choose "PC-compatible" instead.
385 bool "RDC R-321x SoC"
387 depends on X86_EXTENDED_PLATFORM
389 select X86_REBOOTFIXUPS
391 This option is needed for RDC R-321x system-on-chip, also known
393 If you don't have one of these chips, you should say N here.
395 config X86_32_NON_STANDARD
396 bool "Support non-standard 32-bit SMP architectures"
397 depends on X86_32 && SMP
398 depends on X86_EXTENDED_PLATFORM
400 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
401 subarchitectures. It is intended for a generic binary kernel.
402 if you select them all, kernel will probe it one by one. and will
405 # Alphabetically sorted list of Non standard 32 bit platforms
408 bool "NUMAQ (IBM/Sequent)"
409 depends on X86_32_NON_STANDARD
413 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
414 NUMA multiquad box. This changes the way that processors are
415 bootstrapped, and uses Clustered Logical APIC addressing mode instead
416 of Flat Logical. You will need a new lynxer.elf file to flash your
417 firmware with - send email to <Martin.Bligh@us.ibm.com>.
420 bool "SGI 320/540 (Visual Workstation)"
421 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
422 depends on X86_32_NON_STANDARD
424 The SGI Visual Workstation series is an IA32-based workstation
425 based on SGI systems chips with some legacy PC hardware attached.
427 Say Y here to create a kernel to run on the SGI 320 or 540.
429 A kernel compiled for the Visual Workstation will run on general
430 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
433 bool "Summit/EXA (IBM x440)"
434 depends on X86_32_NON_STANDARD
436 This option is needed for IBM systems that use the Summit/EXA chipset.
437 In particular, it is needed for the x440.
440 bool "Unisys ES7000 IA32 series"
441 depends on X86_32_NON_STANDARD && X86_BIGSMP
443 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
444 supposed to run on an IA32-based Unisys ES7000 system.
446 config SCHED_OMIT_FRAME_POINTER
448 prompt "Single-depth WCHAN output"
451 Calculate simpler /proc/<PID>/wchan values. If this option
452 is disabled then wchan values will recurse back to the
453 caller function. This provides more accurate wchan values,
454 at the expense of slightly more scheduling overhead.
456 If in doubt, say "Y".
458 menuconfig PARAVIRT_GUEST
459 bool "Paravirtualized guest support"
461 Say Y here to get to see options related to running Linux under
462 various hypervisors. This option alone does not add any kernel code.
464 If you say N, all options in this submenu will be skipped and disabled.
468 source "arch/x86/xen/Kconfig"
471 bool "VMI Guest support"
475 VMI provides a paravirtualized interface to the VMware ESX server
476 (it could be used by other hypervisors in theory too, but is not
477 at the moment), by linking the kernel to a GPL-ed ROM module
478 provided by the hypervisor.
481 bool "KVM paravirtualized clock"
483 select PARAVIRT_CLOCK
485 Turning on this option will allow you to run a paravirtualized clock
486 when running over the KVM hypervisor. Instead of relying on a PIT
487 (or probably other) emulation by the underlying device model, the host
488 provides the guest with timing infrastructure such as time of day, and
492 bool "KVM Guest support"
495 This option enables various optimizations for running under the KVM
498 source "arch/x86/lguest/Kconfig"
501 bool "Enable paravirtualization code"
503 This changes the kernel so it can modify itself when it is run
504 under a hypervisor, potentially improving performance significantly
505 over full virtualization. However, when run without a hypervisor
506 the kernel is theoretically slower and slightly larger.
508 config PARAVIRT_SPINLOCKS
509 bool "Paravirtualization layer for spinlocks"
510 depends on PARAVIRT && SMP && EXPERIMENTAL
512 Paravirtualized spinlocks allow a pvops backend to replace the
513 spinlock implementation with something virtualization-friendly
514 (for example, block the virtual CPU rather than spinning).
516 Unfortunately the downside is an up to 5% performance hit on
517 native kernels, with various workloads.
519 If you are unsure how to answer this question, answer N.
521 config PARAVIRT_CLOCK
527 config PARAVIRT_DEBUG
528 bool "paravirt-ops debugging"
529 depends on PARAVIRT && DEBUG_KERNEL
531 Enable to debug paravirt_ops internals. Specifically, BUG if
532 a paravirt_op is missing when it is called.
537 This option adds a kernel parameter 'memtest', which allows memtest
539 memtest=0, mean disabled; -- default
540 memtest=1, mean do 1 test pattern;
542 memtest=4, mean do 4 test patterns.
543 If you are unsure how to answer this question, answer N.
545 config X86_SUMMIT_NUMA
547 depends on X86_32 && NUMA && X86_32_NON_STANDARD
549 config X86_CYCLONE_TIMER
551 depends on X86_32_NON_STANDARD
553 source "arch/x86/Kconfig.cpu"
557 prompt "HPET Timer Support" if X86_32
559 Use the IA-PC HPET (High Precision Event Timer) to manage
560 time in preference to the PIT and RTC, if a HPET is
562 HPET is the next generation timer replacing legacy 8254s.
563 The HPET provides a stable time base on SMP
564 systems, unlike the TSC, but it is more expensive to access,
565 as it is off-chip. You can find the HPET spec at
566 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
568 You can safely choose Y here. However, HPET will only be
569 activated if the platform and the BIOS support this feature.
570 Otherwise the 8254 will be used for timing services.
572 Choose N to continue using the legacy 8254 timer.
574 config HPET_EMULATE_RTC
576 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
578 # Mark as embedded because too many people got it wrong.
579 # The code disables itself when not needed.
582 bool "Enable DMI scanning" if EMBEDDED
584 Enabled scanning of DMI to identify machine quirks. Say Y
585 here unless you have verified that your setup is not
586 affected by entries in the DMI blacklist. Required by PNP
590 bool "GART IOMMU support" if EMBEDDED
594 depends on X86_64 && PCI
596 Support for full DMA access of devices with 32bit memory access only
597 on systems with more than 3GB. This is usually needed for USB,
598 sound, many IDE/SATA chipsets and some other devices.
599 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
600 based hardware IOMMU and a software bounce buffer based IOMMU used
601 on Intel systems and as fallback.
602 The code is only active when needed (enough memory and limited
603 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
607 bool "IBM Calgary IOMMU support"
609 depends on X86_64 && PCI && EXPERIMENTAL
611 Support for hardware IOMMUs in IBM's xSeries x366 and x460
612 systems. Needed to run systems with more than 3GB of memory
613 properly with 32-bit PCI devices that do not support DAC
614 (Double Address Cycle). Calgary also supports bus level
615 isolation, where all DMAs pass through the IOMMU. This
616 prevents them from going anywhere except their intended
617 destination. This catches hard-to-find kernel bugs and
618 mis-behaving drivers and devices that do not use the DMA-API
619 properly to set up their DMA buffers. The IOMMU can be
620 turned off at boot time with the iommu=off parameter.
621 Normally the kernel will make the right choice by itself.
624 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
626 prompt "Should Calgary be enabled by default?"
627 depends on CALGARY_IOMMU
629 Should Calgary be enabled by default? if you choose 'y', Calgary
630 will be used (if it exists). If you choose 'n', Calgary will not be
631 used even if it exists. If you choose 'n' and would like to use
632 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
636 bool "AMD IOMMU support"
639 depends on X86_64 && PCI && ACPI
641 With this option you can enable support for AMD IOMMU hardware in
642 your system. An IOMMU is a hardware component which provides
643 remapping of DMA memory accesses from devices. With an AMD IOMMU you
644 can isolate the the DMA memory of different devices and protect the
645 system from misbehaving device drivers or hardware.
647 You can find out if your system has an AMD IOMMU if you look into
648 your BIOS for an option to enable it or if you have an IVRS ACPI
651 config AMD_IOMMU_STATS
652 bool "Export AMD IOMMU statistics to debugfs"
656 This option enables code in the AMD IOMMU driver to collect various
657 statistics about whats happening in the driver and exports that
658 information to userspace via debugfs.
661 # need this always selected by IOMMU for the VIA workaround
665 Support for software bounce buffers used on x86-64 systems
666 which don't have a hardware IOMMU (e.g. the current generation
667 of Intel's x86-64 CPUs). Using this PCI devices which can only
668 access 32-bits of memory can be used on systems with more than
669 3 GB of memory. If unsure, say Y.
672 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
675 def_bool (AMD_IOMMU || DMAR)
678 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
679 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
680 select CPUMASK_OFFSTACK
683 Configure maximum number of CPUS and NUMA Nodes for this architecture.
687 int "Maximum number of CPUs" if SMP && !MAXSMP
688 range 2 8 if SMP && X86_32 && !X86_BIGSMP
689 range 2 512 if SMP && !MAXSMP
691 default "4096" if MAXSMP
692 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
695 This allows you to specify the maximum number of CPUs which this
696 kernel will support. The maximum supported value is 512 and the
697 minimum value which makes sense is 2.
699 This is purely to save memory - each supported CPU adds
700 approximately eight kilobytes to the kernel image.
703 bool "SMT (Hyperthreading) scheduler support"
706 SMT scheduler support improves the CPU scheduler's decision making
707 when dealing with Intel Pentium 4 chips with HyperThreading at a
708 cost of slightly increased overhead in some places. If unsure say
713 prompt "Multi-core scheduler support"
716 Multi-core scheduler support improves the CPU scheduler's decision
717 making when dealing with multi-core CPU chips at a cost of slightly
718 increased overhead in some places. If unsure say N here.
720 source "kernel/Kconfig.preempt"
723 bool "Local APIC support on uniprocessors"
724 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
726 A local APIC (Advanced Programmable Interrupt Controller) is an
727 integrated interrupt controller in the CPU. If you have a single-CPU
728 system which has a processor with a local APIC, you can say Y here to
729 enable and use it. If you say Y here even though your machine doesn't
730 have a local APIC, then the kernel will still run with no slowdown at
731 all. The local APIC supports CPU-generated self-interrupts (timer,
732 performance counters), and the NMI watchdog which detects hard
736 bool "IO-APIC support on uniprocessors"
737 depends on X86_UP_APIC
739 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
740 SMP-capable replacement for PC-style interrupt controllers. Most
741 SMP systems and many recent uniprocessor systems have one.
743 If you have a single-CPU system with an IO-APIC, you can say Y here
744 to use it. If you say Y here even though your machine doesn't have
745 an IO-APIC, then the kernel will still run with no slowdown at all.
747 config X86_LOCAL_APIC
749 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
753 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
755 config X86_VISWS_APIC
757 depends on X86_32 && X86_VISWS
759 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
760 bool "Reroute for broken boot IRQs"
762 depends on X86_IO_APIC
764 This option enables a workaround that fixes a source of
765 spurious interrupts. This is recommended when threaded
766 interrupt handling is used on systems where the generation of
767 superfluous "boot interrupts" cannot be disabled.
769 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
770 entry in the chipset's IO-APIC is masked (as, e.g. the RT
771 kernel does during interrupt handling). On chipsets where this
772 boot IRQ generation cannot be disabled, this workaround keeps
773 the original IRQ line masked so that only the equivalent "boot
774 IRQ" is delivered to the CPUs. The workaround also tells the
775 kernel to set up the IRQ handler on the boot IRQ line. In this
776 way only one interrupt is delivered to the kernel. Otherwise
777 the spurious second interrupt may cause the kernel to bring
778 down (vital) interrupt lines.
780 Only affects "broken" chipsets. Interrupt sharing may be
781 increased on these systems.
784 bool "Machine Check Exception"
786 Machine Check Exception support allows the processor to notify the
787 kernel if it detects a problem (e.g. overheating, component failure).
788 The action the kernel takes depends on the severity of the problem,
789 ranging from a warning message on the console, to halting the machine.
790 Your processor must be a Pentium or newer to support this - check the
791 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
792 have a design flaw which leads to false MCE events - hence MCE is
793 disabled on all P5 processors, unless explicitly enabled with "mce"
794 as a boot argument. Similarly, if MCE is built in and creates a
795 problem on some new non-standard machine, you can boot with "nomce"
796 to disable it. MCE support simply ignores non-MCE processors like
797 the 386 and 486, so nearly everyone can say Y here.
800 depends on X86_32 && X86_MCE
801 bool "Use legacy machine check code (will go away)"
803 select X86_ANCIENT_MCE
805 Use the old i386 machine check code. This is merely intended for
806 testing in a transition period. Try this if you run into any machine
807 check related software problems, but report the problem to
808 linux-kernel. When in doubt say no.
813 default y if (!X86_OLD_MCE && X86_32) || X86_64
817 prompt "Intel MCE features"
818 depends on X86_NEW_MCE && X86_LOCAL_APIC
820 Additional support for intel specific MCE features such as
825 prompt "AMD MCE features"
826 depends on X86_NEW_MCE && X86_LOCAL_APIC
828 Additional support for AMD specific MCE features such as
829 the DRAM Error Threshold.
831 config X86_ANCIENT_MCE
834 prompt "Support for old Pentium 5 / WinChip machine checks"
836 Include support for machine check handling on old Pentium 5 or WinChip
837 systems. These typically need to be enabled explicitely on the command
840 config X86_MCE_THRESHOLD
841 depends on X86_MCE_AMD || X86_MCE_INTEL
845 config X86_MCE_INJECT
846 depends on X86_NEW_MCE
847 tristate "Machine check injector support"
849 Provide support for injecting machine checks for testing purposes.
850 If you don't know what a machine check is and you don't do kernel
851 QA it is safe to say n.
853 config X86_MCE_NONFATAL
854 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
855 depends on X86_OLD_MCE
857 Enabling this feature starts a timer that triggers every 5 seconds which
858 will look at the machine check registers to see if anything happened.
859 Non-fatal problems automatically get corrected (but still logged).
860 Disable this if you don't want to see these messages.
861 Seeing the messages this option prints out may be indicative of dying
862 or out-of-spec (ie, overclocked) hardware.
863 This option only does something on certain CPUs.
864 (AMD Athlon/Duron and Intel Pentium 4)
866 config X86_MCE_P4THERMAL
867 bool "check for P4 thermal throttling interrupt."
868 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
870 Enabling this feature will cause a message to be printed when the P4
871 enters thermal throttling.
873 config X86_THERMAL_VECTOR
875 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
878 bool "Enable VM86 support" if EMBEDDED
882 This option is required by programs like DOSEMU to run 16-bit legacy
883 code on X86 processors. It also may be needed by software like
884 XFree86 to initialize some video cards via BIOS. Disabling this
885 option saves about 6k.
888 tristate "Toshiba Laptop support"
891 This adds a driver to safely access the System Management Mode of
892 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
893 not work on models with a Phoenix BIOS. The System Management Mode
894 is used to set the BIOS and power saving options on Toshiba portables.
896 For information on utilities to make use of this driver see the
897 Toshiba Linux utilities web site at:
898 <http://www.buzzard.org.uk/toshiba/>.
900 Say Y if you intend to run this kernel on a Toshiba portable.
904 tristate "Dell laptop support"
906 This adds a driver to safely access the System Management Mode
907 of the CPU on the Dell Inspiron 8000. The System Management Mode
908 is used to read cpu temperature and cooling fan status and to
909 control the fans on the I8K portables.
911 This driver has been tested only on the Inspiron 8000 but it may
912 also work with other Dell laptops. You can force loading on other
913 models by passing the parameter `force=1' to the module. Use at
916 For information on utilities to make use of this driver see the
917 I8K Linux utilities web site at:
918 <http://people.debian.org/~dz/i8k/>
920 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
923 config X86_REBOOTFIXUPS
924 bool "Enable X86 board specific fixups for reboot"
927 This enables chipset and/or board specific fixups to be done
928 in order to get reboot to work correctly. This is only needed on
929 some combinations of hardware and BIOS. The symptom, for which
930 this config is intended, is when reboot ends with a stalled/hung
933 Currently, the only fixup is for the Geode machines using
934 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
936 Say Y if you want to enable the fixup. Currently, it's safe to
937 enable this option even if you don't need it.
941 tristate "/dev/cpu/microcode - microcode support"
944 If you say Y here, you will be able to update the microcode on
945 certain Intel and AMD processors. The Intel support is for the
946 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
947 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
948 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
949 You will obviously need the actual microcode binary data itself
950 which is not shipped with the Linux kernel.
952 This option selects the general module only, you need to select
953 at least one vendor specific module as well.
955 To compile this driver as a module, choose M here: the
956 module will be called microcode.
958 config MICROCODE_INTEL
959 bool "Intel microcode patch loading support"
964 This options enables microcode patch loading support for Intel
967 For latest news and information on obtaining all the required
968 Intel ingredients for this driver, check:
969 <http://www.urbanmyth.org/microcode/>.
972 bool "AMD microcode patch loading support"
976 If you select this option, microcode patch loading support for AMD
977 processors will be enabled.
979 config MICROCODE_OLD_INTERFACE
984 tristate "/dev/cpu/*/msr - Model-specific register support"
986 This device gives privileged processes access to the x86
987 Model-Specific Registers (MSRs). It is a character device with
988 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
989 MSR accesses are directed to a specific CPU on multi-processor
993 tristate "/dev/cpu/*/cpuid - CPU information support"
995 This device gives processes access to the x86 CPUID instruction to
996 be executed on a specific processor. It is a character device
997 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1000 config X86_CPU_DEBUG
1001 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
1003 If you select this option, this will provide various x86 CPUs
1004 information through debugfs.
1007 prompt "High Memory Support"
1008 default HIGHMEM4G if !X86_NUMAQ
1009 default HIGHMEM64G if X86_NUMAQ
1014 depends on !X86_NUMAQ
1016 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1017 However, the address space of 32-bit x86 processors is only 4
1018 Gigabytes large. That means that, if you have a large amount of
1019 physical memory, not all of it can be "permanently mapped" by the
1020 kernel. The physical memory that's not permanently mapped is called
1023 If you are compiling a kernel which will never run on a machine with
1024 more than 1 Gigabyte total physical RAM, answer "off" here (default
1025 choice and suitable for most users). This will result in a "3GB/1GB"
1026 split: 3GB are mapped so that each process sees a 3GB virtual memory
1027 space and the remaining part of the 4GB virtual memory space is used
1028 by the kernel to permanently map as much physical memory as
1031 If the machine has between 1 and 4 Gigabytes physical RAM, then
1034 If more than 4 Gigabytes is used then answer "64GB" here. This
1035 selection turns Intel PAE (Physical Address Extension) mode on.
1036 PAE implements 3-level paging on IA32 processors. PAE is fully
1037 supported by Linux, PAE mode is implemented on all recent Intel
1038 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1039 then the kernel will not boot on CPUs that don't support PAE!
1041 The actual amount of total physical memory will either be
1042 auto detected or can be forced by using a kernel command line option
1043 such as "mem=256M". (Try "man bootparam" or see the documentation of
1044 your boot loader (lilo or loadlin) about how to pass options to the
1045 kernel at boot time.)
1047 If unsure, say "off".
1051 depends on !X86_NUMAQ
1053 Select this if you have a 32-bit processor and between 1 and 4
1054 gigabytes of physical RAM.
1058 depends on !M386 && !M486
1061 Select this if you have a 32-bit processor and more than 4
1062 gigabytes of physical RAM.
1067 depends on EXPERIMENTAL
1068 prompt "Memory split" if EMBEDDED
1072 Select the desired split between kernel and user memory.
1074 If the address range available to the kernel is less than the
1075 physical memory installed, the remaining memory will be available
1076 as "high memory". Accessing high memory is a little more costly
1077 than low memory, as it needs to be mapped into the kernel first.
1078 Note that increasing the kernel address space limits the range
1079 available to user programs, making the address space there
1080 tighter. Selecting anything other than the default 3G/1G split
1081 will also likely make your kernel incompatible with binary-only
1084 If you are not absolutely sure what you are doing, leave this
1088 bool "3G/1G user/kernel split"
1089 config VMSPLIT_3G_OPT
1091 bool "3G/1G user/kernel split (for full 1G low memory)"
1093 bool "2G/2G user/kernel split"
1094 config VMSPLIT_2G_OPT
1096 bool "2G/2G user/kernel split (for full 2G low memory)"
1098 bool "1G/3G user/kernel split"
1103 default 0xB0000000 if VMSPLIT_3G_OPT
1104 default 0x80000000 if VMSPLIT_2G
1105 default 0x78000000 if VMSPLIT_2G_OPT
1106 default 0x40000000 if VMSPLIT_1G
1112 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1115 bool "PAE (Physical Address Extension) Support"
1116 depends on X86_32 && !HIGHMEM4G
1118 PAE is required for NX support, and furthermore enables
1119 larger swapspace support for non-overcommit purposes. It
1120 has the cost of more pagetable lookup overhead, and also
1121 consumes more pagetable space per process.
1123 config ARCH_PHYS_ADDR_T_64BIT
1124 def_bool X86_64 || X86_PAE
1126 config DIRECT_GBPAGES
1127 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1131 Allow the kernel linear mapping to use 1GB pages on CPUs that
1132 support it. This can improve the kernel's performance a tiny bit by
1133 reducing TLB pressure. If in doubt, say "Y".
1135 # Common NUMA Features
1137 bool "Numa Memory Allocation and Scheduler Support"
1139 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1140 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1142 Enable NUMA (Non Uniform Memory Access) support.
1144 The kernel will try to allocate memory used by a CPU on the
1145 local memory controller of the CPU and add some more
1146 NUMA awareness to the kernel.
1148 For 64-bit this is recommended if the system is Intel Core i7
1149 (or later), AMD Opteron, or EM64T NUMA.
1151 For 32-bit this is only needed on (rare) 32-bit-only platforms
1152 that support NUMA topologies, such as NUMAQ / Summit, or if you
1153 boot a 32-bit kernel on a 64-bit NUMA platform.
1155 Otherwise, you should say N.
1157 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1158 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1162 prompt "Old style AMD Opteron NUMA detection"
1163 depends on X86_64 && NUMA && PCI
1165 Enable K8 NUMA node topology detection. You should say Y here if
1166 you have a multi processor AMD K8 system. This uses an old
1167 method to read the NUMA configuration directly from the builtin
1168 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1169 instead, which also takes priority if both are compiled in.
1171 config X86_64_ACPI_NUMA
1173 prompt "ACPI NUMA detection"
1174 depends on X86_64 && NUMA && ACPI && PCI
1177 Enable ACPI SRAT based node topology detection.
1179 # Some NUMA nodes have memory ranges that span
1180 # other nodes. Even though a pfn is valid and
1181 # between a node's start and end pfns, it may not
1182 # reside on that node. See memmap_init_zone()
1184 config NODES_SPAN_OTHER_NODES
1186 depends on X86_64_ACPI_NUMA
1189 bool "NUMA emulation"
1190 depends on X86_64 && NUMA
1192 Enable NUMA emulation. A flat machine will be split
1193 into virtual nodes when booted with "numa=fake=N", where N is the
1194 number of nodes. This is only useful for debugging.
1197 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1199 default "9" if MAXSMP
1200 default "6" if X86_64
1201 default "4" if X86_NUMAQ
1203 depends on NEED_MULTIPLE_NODES
1205 Specify the maximum number of NUMA Nodes available on the target
1206 system. Increases memory reserved to accommodate various tables.
1208 config HAVE_ARCH_BOOTMEM
1210 depends on X86_32 && NUMA
1212 config ARCH_HAVE_MEMORY_PRESENT
1214 depends on X86_32 && DISCONTIGMEM
1216 config NEED_NODE_MEMMAP_SIZE
1218 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1220 config HAVE_ARCH_ALLOC_REMAP
1222 depends on X86_32 && NUMA
1224 config ARCH_FLATMEM_ENABLE
1226 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1228 config ARCH_DISCONTIGMEM_ENABLE
1230 depends on NUMA && X86_32
1232 config ARCH_DISCONTIGMEM_DEFAULT
1234 depends on NUMA && X86_32
1236 config ARCH_SPARSEMEM_DEFAULT
1240 config ARCH_SPARSEMEM_ENABLE
1242 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1243 select SPARSEMEM_STATIC if X86_32
1244 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1246 config ARCH_SELECT_MEMORY_MODEL
1248 depends on ARCH_SPARSEMEM_ENABLE
1250 config ARCH_MEMORY_PROBE
1252 depends on MEMORY_HOTPLUG
1257 bool "Allocate 3rd-level pagetables from highmem"
1258 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1260 The VM uses one page table entry for each page of physical memory.
1261 For systems with a lot of RAM, this can be wasteful of precious
1262 low memory. Setting this option will put user-space page table
1263 entries in high memory.
1265 config X86_CHECK_BIOS_CORRUPTION
1266 bool "Check for low memory corruption"
1268 Periodically check for memory corruption in low memory, which
1269 is suspected to be caused by BIOS. Even when enabled in the
1270 configuration, it is disabled at runtime. Enable it by
1271 setting "memory_corruption_check=1" on the kernel command
1272 line. By default it scans the low 64k of memory every 60
1273 seconds; see the memory_corruption_check_size and
1274 memory_corruption_check_period parameters in
1275 Documentation/kernel-parameters.txt to adjust this.
1277 When enabled with the default parameters, this option has
1278 almost no overhead, as it reserves a relatively small amount
1279 of memory and scans it infrequently. It both detects corruption
1280 and prevents it from affecting the running system.
1282 It is, however, intended as a diagnostic tool; if repeatable
1283 BIOS-originated corruption always affects the same memory,
1284 you can use memmap= to prevent the kernel from using that
1287 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1288 bool "Set the default setting of memory_corruption_check"
1289 depends on X86_CHECK_BIOS_CORRUPTION
1292 Set whether the default state of memory_corruption_check is
1295 config X86_RESERVE_LOW_64K
1296 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1299 Reserve the first 64K of physical RAM on BIOSes that are known
1300 to potentially corrupt that memory range. A numbers of BIOSes are
1301 known to utilize this area during suspend/resume, so it must not
1302 be used by the kernel.
1304 Set this to N if you are absolutely sure that you trust the BIOS
1305 to get all its memory reservations and usages right.
1307 If you have doubts about the BIOS (e.g. suspend/resume does not
1308 work or there's kernel crashes after certain hardware hotplug
1309 events) and it's not AMI or Phoenix, then you might want to enable
1310 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1311 corruption patterns.
1315 config MATH_EMULATION
1317 prompt "Math emulation" if X86_32
1319 Linux can emulate a math coprocessor (used for floating point
1320 operations) if you don't have one. 486DX and Pentium processors have
1321 a math coprocessor built in, 486SX and 386 do not, unless you added
1322 a 487DX or 387, respectively. (The messages during boot time can
1323 give you some hints here ["man dmesg"].) Everyone needs either a
1324 coprocessor or this emulation.
1326 If you don't have a math coprocessor, you need to say Y here; if you
1327 say Y here even though you have a coprocessor, the coprocessor will
1328 be used nevertheless. (This behavior can be changed with the kernel
1329 command line option "no387", which comes handy if your coprocessor
1330 is broken. Try "man bootparam" or see the documentation of your boot
1331 loader (lilo or loadlin) about how to pass options to the kernel at
1332 boot time.) This means that it is a good idea to say Y here if you
1333 intend to use this kernel on different machines.
1335 More information about the internals of the Linux math coprocessor
1336 emulation can be found in <file:arch/x86/math-emu/README>.
1338 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1339 kernel, it won't hurt.
1342 bool "MTRR (Memory Type Range Register) support"
1344 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1345 the Memory Type Range Registers (MTRRs) may be used to control
1346 processor access to memory ranges. This is most useful if you have
1347 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1348 allows bus write transfers to be combined into a larger transfer
1349 before bursting over the PCI/AGP bus. This can increase performance
1350 of image write operations 2.5 times or more. Saying Y here creates a
1351 /proc/mtrr file which may be used to manipulate your processor's
1352 MTRRs. Typically the X server should use this.
1354 This code has a reasonably generic interface so that similar
1355 control registers on other processors can be easily supported
1358 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1359 Registers (ARRs) which provide a similar functionality to MTRRs. For
1360 these, the ARRs are used to emulate the MTRRs.
1361 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1362 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1363 write-combining. All of these processors are supported by this code
1364 and it makes sense to say Y here if you have one of them.
1366 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1367 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1368 can lead to all sorts of problems, so it's good to say Y here.
1370 You can safely say Y even if your machine doesn't have MTRRs, you'll
1371 just add about 9 KB to your kernel.
1373 See <file:Documentation/x86/mtrr.txt> for more information.
1375 config MTRR_SANITIZER
1377 prompt "MTRR cleanup support"
1380 Convert MTRR layout from continuous to discrete, so X drivers can
1381 add writeback entries.
1383 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1384 The largest mtrr entry size for a continuous block can be set with
1389 config MTRR_SANITIZER_ENABLE_DEFAULT
1390 int "MTRR cleanup enable value (0-1)"
1393 depends on MTRR_SANITIZER
1395 Enable mtrr cleanup default value
1397 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1398 int "MTRR cleanup spare reg num (0-7)"
1401 depends on MTRR_SANITIZER
1403 mtrr cleanup spare entries default, it can be changed via
1404 mtrr_spare_reg_nr=N on the kernel command line.
1408 prompt "x86 PAT support"
1411 Use PAT attributes to setup page level cache control.
1413 PATs are the modern equivalents of MTRRs and are much more
1414 flexible than MTRRs.
1416 Say N here if you see bootup problems (boot crash, boot hang,
1417 spontaneous reboots) or a non-working video driver.
1422 bool "EFI runtime service support"
1425 This enables the kernel to use EFI runtime services that are
1426 available (such as the EFI variable services).
1428 This option is only useful on systems that have EFI firmware.
1429 In addition, you should use the latest ELILO loader available
1430 at <http://elilo.sourceforge.net> in order to take advantage
1431 of EFI runtime services. However, even with this option, the
1432 resultant kernel should continue to boot on existing non-EFI
1437 prompt "Enable seccomp to safely compute untrusted bytecode"
1439 This kernel feature is useful for number crunching applications
1440 that may need to compute untrusted bytecode during their
1441 execution. By using pipes or other transports made available to
1442 the process as file descriptors supporting the read/write
1443 syscalls, it's possible to isolate those applications in
1444 their own address space using seccomp. Once seccomp is
1445 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1446 and the task is only allowed to execute a few safe syscalls
1447 defined by each seccomp mode.
1449 If unsure, say Y. Only embedded should say N here.
1451 config CC_STACKPROTECTOR_ALL
1454 config CC_STACKPROTECTOR
1455 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1456 select CC_STACKPROTECTOR_ALL
1458 This option turns on the -fstack-protector GCC feature. This
1459 feature puts, at the beginning of functions, a canary value on
1460 the stack just before the return address, and validates
1461 the value just before actually returning. Stack based buffer
1462 overflows (that need to overwrite this return address) now also
1463 overwrite the canary, which gets detected and the attack is then
1464 neutralized via a kernel panic.
1466 This feature requires gcc version 4.2 or above, or a distribution
1467 gcc with the feature backported. Older versions are automatically
1468 detected and for those versions, this configuration option is
1469 ignored. (and a warning is printed during bootup)
1471 source kernel/Kconfig.hz
1474 bool "kexec system call"
1476 kexec is a system call that implements the ability to shutdown your
1477 current kernel, and to start another kernel. It is like a reboot
1478 but it is independent of the system firmware. And like a reboot
1479 you can start any kernel with it, not just Linux.
1481 The name comes from the similarity to the exec system call.
1483 It is an ongoing process to be certain the hardware in a machine
1484 is properly shutdown, so do not be surprised if this code does not
1485 initially work for you. It may help to enable device hotplugging
1486 support. As of this writing the exact hardware interface is
1487 strongly in flux, so no good recommendation can be made.
1490 bool "kernel crash dumps"
1491 depends on X86_64 || (X86_32 && HIGHMEM)
1493 Generate crash dump after being started by kexec.
1494 This should be normally only set in special crash dump kernels
1495 which are loaded in the main kernel with kexec-tools into
1496 a specially reserved region and then later executed after
1497 a crash by kdump/kexec. The crash dump kernel must be compiled
1498 to a memory address not used by the main kernel or BIOS using
1499 PHYSICAL_START, or it must be built as a relocatable image
1500 (CONFIG_RELOCATABLE=y).
1501 For more details see Documentation/kdump/kdump.txt
1504 bool "kexec jump (EXPERIMENTAL)"
1505 depends on EXPERIMENTAL
1506 depends on KEXEC && HIBERNATION
1508 Jump between original kernel and kexeced kernel and invoke
1509 code in physical address mode via KEXEC
1511 config PHYSICAL_START
1512 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1515 This gives the physical address where the kernel is loaded.
1517 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1518 bzImage will decompress itself to above physical address and
1519 run from there. Otherwise, bzImage will run from the address where
1520 it has been loaded by the boot loader and will ignore above physical
1523 In normal kdump cases one does not have to set/change this option
1524 as now bzImage can be compiled as a completely relocatable image
1525 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1526 address. This option is mainly useful for the folks who don't want
1527 to use a bzImage for capturing the crash dump and want to use a
1528 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1529 to be specifically compiled to run from a specific memory area
1530 (normally a reserved region) and this option comes handy.
1532 So if you are using bzImage for capturing the crash dump,
1533 leave the value here unchanged to 0x1000000 and set
1534 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1535 for capturing the crash dump change this value to start of
1536 the reserved region. In other words, it can be set based on
1537 the "X" value as specified in the "crashkernel=YM@XM"
1538 command line boot parameter passed to the panic-ed
1539 kernel. Please take a look at Documentation/kdump/kdump.txt
1540 for more details about crash dumps.
1542 Usage of bzImage for capturing the crash dump is recommended as
1543 one does not have to build two kernels. Same kernel can be used
1544 as production kernel and capture kernel. Above option should have
1545 gone away after relocatable bzImage support is introduced. But it
1546 is present because there are users out there who continue to use
1547 vmlinux for dump capture. This option should go away down the
1550 Don't change this unless you know what you are doing.
1553 bool "Build a relocatable kernel"
1556 This builds a kernel image that retains relocation information
1557 so it can be loaded someplace besides the default 1MB.
1558 The relocations tend to make the kernel binary about 10% larger,
1559 but are discarded at runtime.
1561 One use is for the kexec on panic case where the recovery kernel
1562 must live at a different physical address than the primary
1565 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1566 it has been loaded at and the compile time physical address
1567 (CONFIG_PHYSICAL_START) is ignored.
1569 # Relocation on x86-32 needs some additional build support
1570 config X86_NEED_RELOCS
1572 depends on X86_32 && RELOCATABLE
1574 config PHYSICAL_ALIGN
1576 prompt "Alignment value to which kernel should be aligned" if X86_32
1578 range 0x2000 0x1000000
1580 This value puts the alignment restrictions on physical address
1581 where kernel is loaded and run from. Kernel is compiled for an
1582 address which meets above alignment restriction.
1584 If bootloader loads the kernel at a non-aligned address and
1585 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1586 address aligned to above value and run from there.
1588 If bootloader loads the kernel at a non-aligned address and
1589 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1590 load address and decompress itself to the address it has been
1591 compiled for and run from there. The address for which kernel is
1592 compiled already meets above alignment restrictions. Hence the
1593 end result is that kernel runs from a physical address meeting
1594 above alignment restrictions.
1596 Don't change this unless you know what you are doing.
1599 bool "Support for hot-pluggable CPUs"
1600 depends on SMP && HOTPLUG
1602 Say Y here to allow turning CPUs off and on. CPUs can be
1603 controlled through /sys/devices/system/cpu.
1604 ( Note: power management support will enable this option
1605 automatically on SMP systems. )
1606 Say N if you want to disable CPU hotplug.
1610 prompt "Compat VDSO support"
1611 depends on X86_32 || IA32_EMULATION
1613 Map the 32-bit VDSO to the predictable old-style address too.
1615 Say N here if you are running a sufficiently recent glibc
1616 version (2.3.3 or later), to remove the high-mapped
1617 VDSO mapping and to exclusively use the randomized VDSO.
1622 bool "Built-in kernel command line"
1625 Allow for specifying boot arguments to the kernel at
1626 build time. On some systems (e.g. embedded ones), it is
1627 necessary or convenient to provide some or all of the
1628 kernel boot arguments with the kernel itself (that is,
1629 to not rely on the boot loader to provide them.)
1631 To compile command line arguments into the kernel,
1632 set this option to 'Y', then fill in the
1633 the boot arguments in CONFIG_CMDLINE.
1635 Systems with fully functional boot loaders (i.e. non-embedded)
1636 should leave this option set to 'N'.
1639 string "Built-in kernel command string"
1640 depends on CMDLINE_BOOL
1643 Enter arguments here that should be compiled into the kernel
1644 image and used at boot time. If the boot loader provides a
1645 command line at boot time, it is appended to this string to
1646 form the full kernel command line, when the system boots.
1648 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1649 change this behavior.
1651 In most cases, the command line (whether built-in or provided
1652 by the boot loader) should specify the device for the root
1655 config CMDLINE_OVERRIDE
1656 bool "Built-in command line overrides boot loader arguments"
1658 depends on CMDLINE_BOOL
1660 Set this option to 'Y' to have the kernel ignore the boot loader
1661 command line, and use ONLY the built-in command line.
1663 This is used to work around broken boot loaders. This should
1664 be set to 'N' under normal conditions.
1668 config ARCH_ENABLE_MEMORY_HOTPLUG
1670 depends on X86_64 || (X86_32 && HIGHMEM)
1672 config ARCH_ENABLE_MEMORY_HOTREMOVE
1674 depends on MEMORY_HOTPLUG
1676 config HAVE_ARCH_EARLY_PFN_TO_NID
1680 menu "Power management and ACPI options"
1682 config ARCH_HIBERNATION_HEADER
1684 depends on X86_64 && HIBERNATION
1686 source "kernel/power/Kconfig"
1688 source "drivers/acpi/Kconfig"
1693 depends on APM || APM_MODULE
1696 tristate "APM (Advanced Power Management) BIOS support"
1697 depends on X86_32 && PM_SLEEP
1699 APM is a BIOS specification for saving power using several different
1700 techniques. This is mostly useful for battery powered laptops with
1701 APM compliant BIOSes. If you say Y here, the system time will be
1702 reset after a RESUME operation, the /proc/apm device will provide
1703 battery status information, and user-space programs will receive
1704 notification of APM "events" (e.g. battery status change).
1706 If you select "Y" here, you can disable actual use of the APM
1707 BIOS by passing the "apm=off" option to the kernel at boot time.
1709 Note that the APM support is almost completely disabled for
1710 machines with more than one CPU.
1712 In order to use APM, you will need supporting software. For location
1713 and more information, read <file:Documentation/power/pm.txt> and the
1714 Battery Powered Linux mini-HOWTO, available from
1715 <http://www.tldp.org/docs.html#howto>.
1717 This driver does not spin down disk drives (see the hdparm(8)
1718 manpage ("man 8 hdparm") for that), and it doesn't turn off
1719 VESA-compliant "green" monitors.
1721 This driver does not support the TI 4000M TravelMate and the ACER
1722 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1723 desktop machines also don't have compliant BIOSes, and this driver
1724 may cause those machines to panic during the boot phase.
1726 Generally, if you don't have a battery in your machine, there isn't
1727 much point in using this driver and you should say N. If you get
1728 random kernel OOPSes or reboots that don't seem to be related to
1729 anything, try disabling/enabling this option (or disabling/enabling
1732 Some other things you should try when experiencing seemingly random,
1735 1) make sure that you have enough swap space and that it is
1737 2) pass the "no-hlt" option to the kernel
1738 3) switch on floating point emulation in the kernel and pass
1739 the "no387" option to the kernel
1740 4) pass the "floppy=nodma" option to the kernel
1741 5) pass the "mem=4M" option to the kernel (thereby disabling
1742 all but the first 4 MB of RAM)
1743 6) make sure that the CPU is not over clocked.
1744 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1745 8) disable the cache from your BIOS settings
1746 9) install a fan for the video card or exchange video RAM
1747 10) install a better fan for the CPU
1748 11) exchange RAM chips
1749 12) exchange the motherboard.
1751 To compile this driver as a module, choose M here: the
1752 module will be called apm.
1756 config APM_IGNORE_USER_SUSPEND
1757 bool "Ignore USER SUSPEND"
1759 This option will ignore USER SUSPEND requests. On machines with a
1760 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1761 series notebooks, it is necessary to say Y because of a BIOS bug.
1763 config APM_DO_ENABLE
1764 bool "Enable PM at boot time"
1766 Enable APM features at boot time. From page 36 of the APM BIOS
1767 specification: "When disabled, the APM BIOS does not automatically
1768 power manage devices, enter the Standby State, enter the Suspend
1769 State, or take power saving steps in response to CPU Idle calls."
1770 This driver will make CPU Idle calls when Linux is idle (unless this
1771 feature is turned off -- see "Do CPU IDLE calls", below). This
1772 should always save battery power, but more complicated APM features
1773 will be dependent on your BIOS implementation. You may need to turn
1774 this option off if your computer hangs at boot time when using APM
1775 support, or if it beeps continuously instead of suspending. Turn
1776 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1777 T400CDT. This is off by default since most machines do fine without
1781 bool "Make CPU Idle calls when idle"
1783 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1784 On some machines, this can activate improved power savings, such as
1785 a slowed CPU clock rate, when the machine is idle. These idle calls
1786 are made after the idle loop has run for some length of time (e.g.,
1787 333 mS). On some machines, this will cause a hang at boot time or
1788 whenever the CPU becomes idle. (On machines with more than one CPU,
1789 this option does nothing.)
1791 config APM_DISPLAY_BLANK
1792 bool "Enable console blanking using APM"
1794 Enable console blanking using the APM. Some laptops can use this to
1795 turn off the LCD backlight when the screen blanker of the Linux
1796 virtual console blanks the screen. Note that this is only used by
1797 the virtual console screen blanker, and won't turn off the backlight
1798 when using the X Window system. This also doesn't have anything to
1799 do with your VESA-compliant power-saving monitor. Further, this
1800 option doesn't work for all laptops -- it might not turn off your
1801 backlight at all, or it might print a lot of errors to the console,
1802 especially if you are using gpm.
1804 config APM_ALLOW_INTS
1805 bool "Allow interrupts during APM BIOS calls"
1807 Normally we disable external interrupts while we are making calls to
1808 the APM BIOS as a measure to lessen the effects of a badly behaving
1809 BIOS implementation. The BIOS should reenable interrupts if it
1810 needs to. Unfortunately, some BIOSes do not -- especially those in
1811 many of the newer IBM Thinkpads. If you experience hangs when you
1812 suspend, try setting this to Y. Otherwise, say N.
1816 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1818 source "drivers/cpuidle/Kconfig"
1820 source "drivers/idle/Kconfig"
1825 menu "Bus options (PCI etc.)"
1830 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1832 Find out whether you have a PCI motherboard. PCI is the name of a
1833 bus system, i.e. the way the CPU talks to the other stuff inside
1834 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1835 VESA. If you have PCI, say Y, otherwise N.
1838 prompt "PCI access mode"
1839 depends on X86_32 && PCI
1842 On PCI systems, the BIOS can be used to detect the PCI devices and
1843 determine their configuration. However, some old PCI motherboards
1844 have BIOS bugs and may crash if this is done. Also, some embedded
1845 PCI-based systems don't have any BIOS at all. Linux can also try to
1846 detect the PCI hardware directly without using the BIOS.
1848 With this option, you can specify how Linux should detect the
1849 PCI devices. If you choose "BIOS", the BIOS will be used,
1850 if you choose "Direct", the BIOS won't be used, and if you
1851 choose "MMConfig", then PCI Express MMCONFIG will be used.
1852 If you choose "Any", the kernel will try MMCONFIG, then the
1853 direct access method and falls back to the BIOS if that doesn't
1854 work. If unsure, go with the default, which is "Any".
1859 config PCI_GOMMCONFIG
1876 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1878 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1881 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1885 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1889 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1896 bool "Support mmconfig PCI config space access"
1897 depends on X86_64 && PCI && ACPI
1900 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1901 depends on PCI_MSI && ACPI && EXPERIMENTAL
1903 DMA remapping (DMAR) devices support enables independent address
1904 translations for Direct Memory Access (DMA) from devices.
1905 These DMA remapping devices are reported via ACPI tables
1906 and include PCI device scope covered by these DMA
1909 config DMAR_DEFAULT_ON
1911 prompt "Enable DMA Remapping Devices by default"
1914 Selecting this option will enable a DMAR device at boot time if
1915 one is found. If this option is not selected, DMAR support can
1916 be enabled by passing intel_iommu=on to the kernel. It is
1917 recommended you say N here while the DMAR code remains
1920 config DMAR_BROKEN_GFX_WA
1922 prompt "Workaround broken graphics drivers (going away soon)"
1925 Current Graphics drivers tend to use physical address
1926 for DMA and avoid using DMA APIs. Setting this config
1927 option permits the IOMMU driver to set a unity map for
1928 all the OS-visible memory. Hence the driver can continue
1929 to use physical addresses for DMA, at least until this
1930 option is removed in the 2.6.32 kernel.
1932 config DMAR_FLOPPY_WA
1936 Floppy disk drivers are known to bypass DMA API calls
1937 thereby failing to work when IOMMU is enabled. This
1938 workaround will setup a 1:1 mapping for the first
1939 16MiB to make floppy (an ISA device) work.
1942 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1943 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1945 Supports Interrupt remapping for IO-APIC and MSI devices.
1946 To use x2apic mode in the CPU's which support x2APIC enhancements or
1947 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1949 source "drivers/pci/pcie/Kconfig"
1951 source "drivers/pci/Kconfig"
1953 # x86_64 have no ISA slots, but do have ISA-style DMA.
1962 Find out whether you have ISA slots on your motherboard. ISA is the
1963 name of a bus system, i.e. the way the CPU talks to the other stuff
1964 inside your box. Other bus systems are PCI, EISA, MicroChannel
1965 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1966 newer boards don't support it. If you have ISA, say Y, otherwise N.
1972 The Extended Industry Standard Architecture (EISA) bus was
1973 developed as an open alternative to the IBM MicroChannel bus.
1975 The EISA bus provided some of the features of the IBM MicroChannel
1976 bus while maintaining backward compatibility with cards made for
1977 the older ISA bus. The EISA bus saw limited use between 1988 and
1978 1995 when it was made obsolete by the PCI bus.
1980 Say Y here if you are building a kernel for an EISA-based machine.
1984 source "drivers/eisa/Kconfig"
1989 MicroChannel Architecture is found in some IBM PS/2 machines and
1990 laptops. It is a bus system similar to PCI or ISA. See
1991 <file:Documentation/mca.txt> (and especially the web page given
1992 there) before attempting to build an MCA bus kernel.
1994 source "drivers/mca/Kconfig"
1997 tristate "NatSemi SCx200 support"
1999 This provides basic support for National Semiconductor's
2000 (now AMD's) Geode processors. The driver probes for the
2001 PCI-IDs of several on-chip devices, so its a good dependency
2002 for other scx200_* drivers.
2004 If compiled as a module, the driver is named scx200.
2006 config SCx200HR_TIMER
2007 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2008 depends on SCx200 && GENERIC_TIME
2011 This driver provides a clocksource built upon the on-chip
2012 27MHz high-resolution timer. Its also a workaround for
2013 NSC Geode SC-1100's buggy TSC, which loses time when the
2014 processor goes idle (as is done by the scheduler). The
2015 other workaround is idle=poll boot option.
2017 config GEODE_MFGPT_TIMER
2019 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2020 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2022 This driver provides a clock event source based on the MFGPT
2023 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2024 MFGPTs have a better resolution and max interval than the
2025 generic PIT, and are suitable for use as high-res timers.
2028 bool "One Laptop Per Child support"
2031 Add support for detecting the unique features of the OLPC
2038 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2040 source "drivers/pcmcia/Kconfig"
2042 source "drivers/pci/hotplug/Kconfig"
2047 menu "Executable file formats / Emulations"
2049 source "fs/Kconfig.binfmt"
2051 config IA32_EMULATION
2052 bool "IA32 Emulation"
2054 select COMPAT_BINFMT_ELF
2056 Include code to run 32-bit programs under a 64-bit kernel. You should
2057 likely turn this on, unless you're 100% sure that you don't have any
2058 32-bit programs left.
2061 tristate "IA32 a.out support"
2062 depends on IA32_EMULATION
2064 Support old a.out binaries in the 32bit emulation.
2068 depends on IA32_EMULATION
2070 config COMPAT_FOR_U64_ALIGNMENT
2074 config SYSVIPC_COMPAT
2076 depends on COMPAT && SYSVIPC
2081 config HAVE_ATOMIC_IOMAP
2085 source "net/Kconfig"
2087 source "drivers/Kconfig"
2089 source "drivers/firmware/Kconfig"
2093 source "arch/x86/Kconfig.debug"
2095 source "security/Kconfig"
2097 source "crypto/Kconfig"
2099 source "arch/x86/kvm/Kconfig"
2101 source "lib/Kconfig"