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.
277 config NUMA_MIGRATE_IRQ_DESC
278 bool "Move irq desc when changing irq smp_affinity"
279 depends on SPARSE_IRQ && NUMA
282 This enables moving irq_desc to cpu/node that irq will use handled.
284 If you don't know what to do here, say N.
287 bool "Enable MPS table" if ACPI
289 depends on X86_LOCAL_APIC
291 For old smp systems that do not have proper acpi support. Newer systems
292 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
295 bool "Support for big SMP systems with more than 8 CPUs"
296 depends on X86_32 && SMP
298 This option is needed for the systems that have more than 8 CPUs
301 config X86_EXTENDED_PLATFORM
302 bool "Support for extended (non-PC) x86 platforms"
305 If you disable this option then the kernel will only support
306 standard PC platforms. (which covers the vast majority of
309 If you enable this option then you'll be able to select support
310 for the following (non-PC) 32 bit x86 platforms:
314 SGI 320/540 (Visual Workstation)
315 Summit/EXA (IBM x440)
316 Unisys ES7000 IA32 series
318 If you have one of these systems, or if you want to build a
319 generic distribution kernel, say Y here - otherwise say N.
323 config X86_EXTENDED_PLATFORM
324 bool "Support for extended (non-PC) x86 platforms"
327 If you disable this option then the kernel will only support
328 standard PC platforms. (which covers the vast majority of
331 If you enable this option then you'll be able to select support
332 for the following (non-PC) 64 bit x86 platforms:
336 If you have one of these systems, or if you want to build a
337 generic distribution kernel, say Y here - otherwise say N.
339 # This is an alphabetically sorted list of 64 bit extended platforms
340 # Please maintain the alphabetic order if and when there are additions
345 depends on X86_64 && PCI
346 depends on X86_EXTENDED_PLATFORM
348 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
349 supposed to run on these EM64T-based machines. Only choose this option
350 if you have one of these machines.
353 bool "SGI Ultraviolet"
355 depends on X86_EXTENDED_PLATFORM
358 This option is needed in order to support SGI Ultraviolet systems.
359 If you don't have one of these, you should say N here.
361 # Following is an alphabetically sorted list of 32 bit extended platforms
362 # Please maintain the alphabetic order if and when there are additions
367 depends on X86_EXTENDED_PLATFORM
369 Select this for an AMD Elan processor.
371 Do not use this option for K6/Athlon/Opteron processors!
373 If unsure, choose "PC-compatible" instead.
376 bool "RDC R-321x SoC"
378 depends on X86_EXTENDED_PLATFORM
380 select X86_REBOOTFIXUPS
382 This option is needed for RDC R-321x system-on-chip, also known
384 If you don't have one of these chips, you should say N here.
386 config X86_32_NON_STANDARD
387 bool "Support non-standard 32-bit SMP architectures"
388 depends on X86_32 && SMP
389 depends on X86_EXTENDED_PLATFORM
391 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
392 subarchitectures. It is intended for a generic binary kernel.
393 if you select them all, kernel will probe it one by one. and will
396 # Alphabetically sorted list of Non standard 32 bit platforms
399 bool "NUMAQ (IBM/Sequent)"
400 depends on X86_32_NON_STANDARD
404 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
405 NUMA multiquad box. This changes the way that processors are
406 bootstrapped, and uses Clustered Logical APIC addressing mode instead
407 of Flat Logical. You will need a new lynxer.elf file to flash your
408 firmware with - send email to <Martin.Bligh@us.ibm.com>.
411 bool "SGI 320/540 (Visual Workstation)"
412 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
413 depends on X86_32_NON_STANDARD
415 The SGI Visual Workstation series is an IA32-based workstation
416 based on SGI systems chips with some legacy PC hardware attached.
418 Say Y here to create a kernel to run on the SGI 320 or 540.
420 A kernel compiled for the Visual Workstation will run on general
421 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
424 bool "Summit/EXA (IBM x440)"
425 depends on X86_32_NON_STANDARD
427 This option is needed for IBM systems that use the Summit/EXA chipset.
428 In particular, it is needed for the x440.
431 bool "Unisys ES7000 IA32 series"
432 depends on X86_32_NON_STANDARD && X86_BIGSMP
434 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
435 supposed to run on an IA32-based Unisys ES7000 system.
437 config SCHED_OMIT_FRAME_POINTER
439 prompt "Single-depth WCHAN output"
442 Calculate simpler /proc/<PID>/wchan values. If this option
443 is disabled then wchan values will recurse back to the
444 caller function. This provides more accurate wchan values,
445 at the expense of slightly more scheduling overhead.
447 If in doubt, say "Y".
449 menuconfig PARAVIRT_GUEST
450 bool "Paravirtualized guest support"
452 Say Y here to get to see options related to running Linux under
453 various hypervisors. This option alone does not add any kernel code.
455 If you say N, all options in this submenu will be skipped and disabled.
459 source "arch/x86/xen/Kconfig"
462 bool "VMI Guest support"
466 VMI provides a paravirtualized interface to the VMware ESX server
467 (it could be used by other hypervisors in theory too, but is not
468 at the moment), by linking the kernel to a GPL-ed ROM module
469 provided by the hypervisor.
472 bool "KVM paravirtualized clock"
474 select PARAVIRT_CLOCK
476 Turning on this option will allow you to run a paravirtualized clock
477 when running over the KVM hypervisor. Instead of relying on a PIT
478 (or probably other) emulation by the underlying device model, the host
479 provides the guest with timing infrastructure such as time of day, and
483 bool "KVM Guest support"
486 This option enables various optimizations for running under the KVM
489 source "arch/x86/lguest/Kconfig"
492 bool "Enable paravirtualization code"
494 This changes the kernel so it can modify itself when it is run
495 under a hypervisor, potentially improving performance significantly
496 over full virtualization. However, when run without a hypervisor
497 the kernel is theoretically slower and slightly larger.
499 config PARAVIRT_CLOCK
505 config PARAVIRT_DEBUG
506 bool "paravirt-ops debugging"
507 depends on PARAVIRT && DEBUG_KERNEL
509 Enable to debug paravirt_ops internals. Specifically, BUG if
510 a paravirt_op is missing when it is called.
515 This option adds a kernel parameter 'memtest', which allows memtest
517 memtest=0, mean disabled; -- default
518 memtest=1, mean do 1 test pattern;
520 memtest=4, mean do 4 test patterns.
521 If you are unsure how to answer this question, answer N.
523 config X86_SUMMIT_NUMA
525 depends on X86_32 && NUMA && X86_32_NON_STANDARD
527 config X86_CYCLONE_TIMER
529 depends on X86_32_NON_STANDARD
531 source "arch/x86/Kconfig.cpu"
535 prompt "HPET Timer Support" if X86_32
537 Use the IA-PC HPET (High Precision Event Timer) to manage
538 time in preference to the PIT and RTC, if a HPET is
540 HPET is the next generation timer replacing legacy 8254s.
541 The HPET provides a stable time base on SMP
542 systems, unlike the TSC, but it is more expensive to access,
543 as it is off-chip. You can find the HPET spec at
544 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
546 You can safely choose Y here. However, HPET will only be
547 activated if the platform and the BIOS support this feature.
548 Otherwise the 8254 will be used for timing services.
550 Choose N to continue using the legacy 8254 timer.
552 config HPET_EMULATE_RTC
554 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
556 # Mark as embedded because too many people got it wrong.
557 # The code disables itself when not needed.
560 bool "Enable DMI scanning" if EMBEDDED
562 Enabled scanning of DMI to identify machine quirks. Say Y
563 here unless you have verified that your setup is not
564 affected by entries in the DMI blacklist. Required by PNP
568 bool "GART IOMMU support" if EMBEDDED
572 depends on X86_64 && PCI
574 Support for full DMA access of devices with 32bit memory access only
575 on systems with more than 3GB. This is usually needed for USB,
576 sound, many IDE/SATA chipsets and some other devices.
577 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
578 based hardware IOMMU and a software bounce buffer based IOMMU used
579 on Intel systems and as fallback.
580 The code is only active when needed (enough memory and limited
581 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
585 bool "IBM Calgary IOMMU support"
587 depends on X86_64 && PCI && EXPERIMENTAL
589 Support for hardware IOMMUs in IBM's xSeries x366 and x460
590 systems. Needed to run systems with more than 3GB of memory
591 properly with 32-bit PCI devices that do not support DAC
592 (Double Address Cycle). Calgary also supports bus level
593 isolation, where all DMAs pass through the IOMMU. This
594 prevents them from going anywhere except their intended
595 destination. This catches hard-to-find kernel bugs and
596 mis-behaving drivers and devices that do not use the DMA-API
597 properly to set up their DMA buffers. The IOMMU can be
598 turned off at boot time with the iommu=off parameter.
599 Normally the kernel will make the right choice by itself.
602 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
604 prompt "Should Calgary be enabled by default?"
605 depends on CALGARY_IOMMU
607 Should Calgary be enabled by default? if you choose 'y', Calgary
608 will be used (if it exists). If you choose 'n', Calgary will not be
609 used even if it exists. If you choose 'n' and would like to use
610 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
614 bool "AMD IOMMU support"
617 depends on X86_64 && PCI && ACPI
619 With this option you can enable support for AMD IOMMU hardware in
620 your system. An IOMMU is a hardware component which provides
621 remapping of DMA memory accesses from devices. With an AMD IOMMU you
622 can isolate the the DMA memory of different devices and protect the
623 system from misbehaving device drivers or hardware.
625 You can find out if your system has an AMD IOMMU if you look into
626 your BIOS for an option to enable it or if you have an IVRS ACPI
629 config AMD_IOMMU_STATS
630 bool "Export AMD IOMMU statistics to debugfs"
634 This option enables code in the AMD IOMMU driver to collect various
635 statistics about whats happening in the driver and exports that
636 information to userspace via debugfs.
639 # need this always selected by IOMMU for the VIA workaround
643 Support for software bounce buffers used on x86-64 systems
644 which don't have a hardware IOMMU (e.g. the current generation
645 of Intel's x86-64 CPUs). Using this PCI devices which can only
646 access 32-bits of memory can be used on systems with more than
647 3 GB of memory. If unsure, say Y.
650 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
653 def_bool (AMD_IOMMU || DMAR)
656 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
657 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
658 select CPUMASK_OFFSTACK
661 Configure maximum number of CPUS and NUMA Nodes for this architecture.
665 int "Maximum number of CPUs" if SMP && !MAXSMP
666 range 2 512 if SMP && !MAXSMP
668 default "4096" if MAXSMP
669 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
672 This allows you to specify the maximum number of CPUs which this
673 kernel will support. The maximum supported value is 512 and the
674 minimum value which makes sense is 2.
676 This is purely to save memory - each supported CPU adds
677 approximately eight kilobytes to the kernel image.
680 bool "SMT (Hyperthreading) scheduler support"
683 SMT scheduler support improves the CPU scheduler's decision making
684 when dealing with Intel Pentium 4 chips with HyperThreading at a
685 cost of slightly increased overhead in some places. If unsure say
690 prompt "Multi-core scheduler support"
693 Multi-core scheduler support improves the CPU scheduler's decision
694 making when dealing with multi-core CPU chips at a cost of slightly
695 increased overhead in some places. If unsure say N here.
697 source "kernel/Kconfig.preempt"
700 bool "Local APIC support on uniprocessors"
701 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
703 A local APIC (Advanced Programmable Interrupt Controller) is an
704 integrated interrupt controller in the CPU. If you have a single-CPU
705 system which has a processor with a local APIC, you can say Y here to
706 enable and use it. If you say Y here even though your machine doesn't
707 have a local APIC, then the kernel will still run with no slowdown at
708 all. The local APIC supports CPU-generated self-interrupts (timer,
709 performance counters), and the NMI watchdog which detects hard
713 bool "IO-APIC support on uniprocessors"
714 depends on X86_UP_APIC
716 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
717 SMP-capable replacement for PC-style interrupt controllers. Most
718 SMP systems and many recent uniprocessor systems have one.
720 If you have a single-CPU system with an IO-APIC, you can say Y here
721 to use it. If you say Y here even though your machine doesn't have
722 an IO-APIC, then the kernel will still run with no slowdown at all.
724 config X86_LOCAL_APIC
726 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
730 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
732 config X86_VISWS_APIC
734 depends on X86_32 && X86_VISWS
736 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
737 bool "Reroute for broken boot IRQs"
739 depends on X86_IO_APIC
741 This option enables a workaround that fixes a source of
742 spurious interrupts. This is recommended when threaded
743 interrupt handling is used on systems where the generation of
744 superfluous "boot interrupts" cannot be disabled.
746 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
747 entry in the chipset's IO-APIC is masked (as, e.g. the RT
748 kernel does during interrupt handling). On chipsets where this
749 boot IRQ generation cannot be disabled, this workaround keeps
750 the original IRQ line masked so that only the equivalent "boot
751 IRQ" is delivered to the CPUs. The workaround also tells the
752 kernel to set up the IRQ handler on the boot IRQ line. In this
753 way only one interrupt is delivered to the kernel. Otherwise
754 the spurious second interrupt may cause the kernel to bring
755 down (vital) interrupt lines.
757 Only affects "broken" chipsets. Interrupt sharing may be
758 increased on these systems.
761 bool "Machine Check Exception"
763 Machine Check Exception support allows the processor to notify the
764 kernel if it detects a problem (e.g. overheating, component failure).
765 The action the kernel takes depends on the severity of the problem,
766 ranging from a warning message on the console, to halting the machine.
767 Your processor must be a Pentium or newer to support this - check the
768 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
769 have a design flaw which leads to false MCE events - hence MCE is
770 disabled on all P5 processors, unless explicitly enabled with "mce"
771 as a boot argument. Similarly, if MCE is built in and creates a
772 problem on some new non-standard machine, you can boot with "nomce"
773 to disable it. MCE support simply ignores non-MCE processors like
774 the 386 and 486, so nearly everyone can say Y here.
778 prompt "Intel MCE features"
779 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
781 Additional support for intel specific MCE features such as
786 prompt "AMD MCE features"
787 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
789 Additional support for AMD specific MCE features such as
790 the DRAM Error Threshold.
792 config X86_MCE_THRESHOLD
793 depends on X86_MCE_AMD || X86_MCE_INTEL
797 config X86_MCE_NONFATAL
798 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
799 depends on X86_32 && X86_MCE
801 Enabling this feature starts a timer that triggers every 5 seconds which
802 will look at the machine check registers to see if anything happened.
803 Non-fatal problems automatically get corrected (but still logged).
804 Disable this if you don't want to see these messages.
805 Seeing the messages this option prints out may be indicative of dying
806 or out-of-spec (ie, overclocked) hardware.
807 This option only does something on certain CPUs.
808 (AMD Athlon/Duron and Intel Pentium 4)
810 config X86_MCE_P4THERMAL
811 bool "check for P4 thermal throttling interrupt."
812 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
814 Enabling this feature will cause a message to be printed when the P4
815 enters thermal throttling.
818 bool "Enable VM86 support" if EMBEDDED
822 This option is required by programs like DOSEMU to run 16-bit legacy
823 code on X86 processors. It also may be needed by software like
824 XFree86 to initialize some video cards via BIOS. Disabling this
825 option saves about 6k.
828 tristate "Toshiba Laptop support"
831 This adds a driver to safely access the System Management Mode of
832 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
833 not work on models with a Phoenix BIOS. The System Management Mode
834 is used to set the BIOS and power saving options on Toshiba portables.
836 For information on utilities to make use of this driver see the
837 Toshiba Linux utilities web site at:
838 <http://www.buzzard.org.uk/toshiba/>.
840 Say Y if you intend to run this kernel on a Toshiba portable.
844 tristate "Dell laptop support"
846 This adds a driver to safely access the System Management Mode
847 of the CPU on the Dell Inspiron 8000. The System Management Mode
848 is used to read cpu temperature and cooling fan status and to
849 control the fans on the I8K portables.
851 This driver has been tested only on the Inspiron 8000 but it may
852 also work with other Dell laptops. You can force loading on other
853 models by passing the parameter `force=1' to the module. Use at
856 For information on utilities to make use of this driver see the
857 I8K Linux utilities web site at:
858 <http://people.debian.org/~dz/i8k/>
860 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
863 config X86_REBOOTFIXUPS
864 bool "Enable X86 board specific fixups for reboot"
867 This enables chipset and/or board specific fixups to be done
868 in order to get reboot to work correctly. This is only needed on
869 some combinations of hardware and BIOS. The symptom, for which
870 this config is intended, is when reboot ends with a stalled/hung
873 Currently, the only fixup is for the Geode machines using
874 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
876 Say Y if you want to enable the fixup. Currently, it's safe to
877 enable this option even if you don't need it.
881 tristate "/dev/cpu/microcode - microcode support"
884 If you say Y here, you will be able to update the microcode on
885 certain Intel and AMD processors. The Intel support is for the
886 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
887 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
888 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
889 You will obviously need the actual microcode binary data itself
890 which is not shipped with the Linux kernel.
892 This option selects the general module only, you need to select
893 at least one vendor specific module as well.
895 To compile this driver as a module, choose M here: the
896 module will be called microcode.
898 config MICROCODE_INTEL
899 bool "Intel microcode patch loading support"
904 This options enables microcode patch loading support for Intel
907 For latest news and information on obtaining all the required
908 Intel ingredients for this driver, check:
909 <http://www.urbanmyth.org/microcode/>.
912 bool "AMD microcode patch loading support"
916 If you select this option, microcode patch loading support for AMD
917 processors will be enabled.
919 config MICROCODE_OLD_INTERFACE
924 tristate "/dev/cpu/*/msr - Model-specific register support"
926 This device gives privileged processes access to the x86
927 Model-Specific Registers (MSRs). It is a character device with
928 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
929 MSR accesses are directed to a specific CPU on multi-processor
933 tristate "/dev/cpu/*/cpuid - CPU information support"
935 This device gives processes access to the x86 CPUID instruction to
936 be executed on a specific processor. It is a character device
937 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
941 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
943 If you select this option, this will provide various x86 CPUs
944 information through debugfs.
947 prompt "High Memory Support"
948 default HIGHMEM4G if !X86_NUMAQ
949 default HIGHMEM64G if X86_NUMAQ
954 depends on !X86_NUMAQ
956 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
957 However, the address space of 32-bit x86 processors is only 4
958 Gigabytes large. That means that, if you have a large amount of
959 physical memory, not all of it can be "permanently mapped" by the
960 kernel. The physical memory that's not permanently mapped is called
963 If you are compiling a kernel which will never run on a machine with
964 more than 1 Gigabyte total physical RAM, answer "off" here (default
965 choice and suitable for most users). This will result in a "3GB/1GB"
966 split: 3GB are mapped so that each process sees a 3GB virtual memory
967 space and the remaining part of the 4GB virtual memory space is used
968 by the kernel to permanently map as much physical memory as
971 If the machine has between 1 and 4 Gigabytes physical RAM, then
974 If more than 4 Gigabytes is used then answer "64GB" here. This
975 selection turns Intel PAE (Physical Address Extension) mode on.
976 PAE implements 3-level paging on IA32 processors. PAE is fully
977 supported by Linux, PAE mode is implemented on all recent Intel
978 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
979 then the kernel will not boot on CPUs that don't support PAE!
981 The actual amount of total physical memory will either be
982 auto detected or can be forced by using a kernel command line option
983 such as "mem=256M". (Try "man bootparam" or see the documentation of
984 your boot loader (lilo or loadlin) about how to pass options to the
985 kernel at boot time.)
987 If unsure, say "off".
991 depends on !X86_NUMAQ
993 Select this if you have a 32-bit processor and between 1 and 4
994 gigabytes of physical RAM.
998 depends on !M386 && !M486
1001 Select this if you have a 32-bit processor and more than 4
1002 gigabytes of physical RAM.
1007 depends on EXPERIMENTAL
1008 prompt "Memory split" if EMBEDDED
1012 Select the desired split between kernel and user memory.
1014 If the address range available to the kernel is less than the
1015 physical memory installed, the remaining memory will be available
1016 as "high memory". Accessing high memory is a little more costly
1017 than low memory, as it needs to be mapped into the kernel first.
1018 Note that increasing the kernel address space limits the range
1019 available to user programs, making the address space there
1020 tighter. Selecting anything other than the default 3G/1G split
1021 will also likely make your kernel incompatible with binary-only
1024 If you are not absolutely sure what you are doing, leave this
1028 bool "3G/1G user/kernel split"
1029 config VMSPLIT_3G_OPT
1031 bool "3G/1G user/kernel split (for full 1G low memory)"
1033 bool "2G/2G user/kernel split"
1034 config VMSPLIT_2G_OPT
1036 bool "2G/2G user/kernel split (for full 2G low memory)"
1038 bool "1G/3G user/kernel split"
1043 default 0xB0000000 if VMSPLIT_3G_OPT
1044 default 0x80000000 if VMSPLIT_2G
1045 default 0x78000000 if VMSPLIT_2G_OPT
1046 default 0x40000000 if VMSPLIT_1G
1052 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1055 bool "PAE (Physical Address Extension) Support"
1056 depends on X86_32 && !HIGHMEM4G
1058 PAE is required for NX support, and furthermore enables
1059 larger swapspace support for non-overcommit purposes. It
1060 has the cost of more pagetable lookup overhead, and also
1061 consumes more pagetable space per process.
1063 config ARCH_PHYS_ADDR_T_64BIT
1064 def_bool X86_64 || X86_PAE
1066 config DIRECT_GBPAGES
1067 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1071 Allow the kernel linear mapping to use 1GB pages on CPUs that
1072 support it. This can improve the kernel's performance a tiny bit by
1073 reducing TLB pressure. If in doubt, say "Y".
1075 # Common NUMA Features
1077 bool "Numa Memory Allocation and Scheduler Support"
1079 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1080 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1082 Enable NUMA (Non Uniform Memory Access) support.
1084 The kernel will try to allocate memory used by a CPU on the
1085 local memory controller of the CPU and add some more
1086 NUMA awareness to the kernel.
1088 For 64-bit this is recommended if the system is Intel Core i7
1089 (or later), AMD Opteron, or EM64T NUMA.
1091 For 32-bit this is only needed on (rare) 32-bit-only platforms
1092 that support NUMA topologies, such as NUMAQ / Summit, or if you
1093 boot a 32-bit kernel on a 64-bit NUMA platform.
1095 Otherwise, you should say N.
1097 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1098 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1102 prompt "Old style AMD Opteron NUMA detection"
1103 depends on X86_64 && NUMA && PCI
1105 Enable K8 NUMA node topology detection. You should say Y here if
1106 you have a multi processor AMD K8 system. This uses an old
1107 method to read the NUMA configuration directly from the builtin
1108 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1109 instead, which also takes priority if both are compiled in.
1111 config X86_64_ACPI_NUMA
1113 prompt "ACPI NUMA detection"
1114 depends on X86_64 && NUMA && ACPI && PCI
1117 Enable ACPI SRAT based node topology detection.
1119 # Some NUMA nodes have memory ranges that span
1120 # other nodes. Even though a pfn is valid and
1121 # between a node's start and end pfns, it may not
1122 # reside on that node. See memmap_init_zone()
1124 config NODES_SPAN_OTHER_NODES
1126 depends on X86_64_ACPI_NUMA
1129 bool "NUMA emulation"
1130 depends on X86_64 && NUMA
1132 Enable NUMA emulation. A flat machine will be split
1133 into virtual nodes when booted with "numa=fake=N", where N is the
1134 number of nodes. This is only useful for debugging.
1137 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1139 default "9" if MAXSMP
1140 default "6" if X86_64
1141 default "4" if X86_NUMAQ
1143 depends on NEED_MULTIPLE_NODES
1145 Specify the maximum number of NUMA Nodes available on the target
1146 system. Increases memory reserved to accommodate various tables.
1148 config HAVE_ARCH_BOOTMEM
1150 depends on X86_32 && NUMA
1152 config ARCH_HAVE_MEMORY_PRESENT
1154 depends on X86_32 && DISCONTIGMEM
1156 config NEED_NODE_MEMMAP_SIZE
1158 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1160 config HAVE_ARCH_ALLOC_REMAP
1162 depends on X86_32 && NUMA
1164 config ARCH_FLATMEM_ENABLE
1166 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1168 config ARCH_DISCONTIGMEM_ENABLE
1170 depends on NUMA && X86_32
1172 config ARCH_DISCONTIGMEM_DEFAULT
1174 depends on NUMA && X86_32
1176 config ARCH_SPARSEMEM_DEFAULT
1180 config ARCH_SPARSEMEM_ENABLE
1182 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1183 select SPARSEMEM_STATIC if X86_32
1184 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1186 config ARCH_SELECT_MEMORY_MODEL
1188 depends on ARCH_SPARSEMEM_ENABLE
1190 config ARCH_MEMORY_PROBE
1192 depends on MEMORY_HOTPLUG
1197 bool "Allocate 3rd-level pagetables from highmem"
1198 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1200 The VM uses one page table entry for each page of physical memory.
1201 For systems with a lot of RAM, this can be wasteful of precious
1202 low memory. Setting this option will put user-space page table
1203 entries in high memory.
1205 config X86_CHECK_BIOS_CORRUPTION
1206 bool "Check for low memory corruption"
1208 Periodically check for memory corruption in low memory, which
1209 is suspected to be caused by BIOS. Even when enabled in the
1210 configuration, it is disabled at runtime. Enable it by
1211 setting "memory_corruption_check=1" on the kernel command
1212 line. By default it scans the low 64k of memory every 60
1213 seconds; see the memory_corruption_check_size and
1214 memory_corruption_check_period parameters in
1215 Documentation/kernel-parameters.txt to adjust this.
1217 When enabled with the default parameters, this option has
1218 almost no overhead, as it reserves a relatively small amount
1219 of memory and scans it infrequently. It both detects corruption
1220 and prevents it from affecting the running system.
1222 It is, however, intended as a diagnostic tool; if repeatable
1223 BIOS-originated corruption always affects the same memory,
1224 you can use memmap= to prevent the kernel from using that
1227 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1228 bool "Set the default setting of memory_corruption_check"
1229 depends on X86_CHECK_BIOS_CORRUPTION
1232 Set whether the default state of memory_corruption_check is
1235 config X86_RESERVE_LOW_64K
1236 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1239 Reserve the first 64K of physical RAM on BIOSes that are known
1240 to potentially corrupt that memory range. A numbers of BIOSes are
1241 known to utilize this area during suspend/resume, so it must not
1242 be used by the kernel.
1244 Set this to N if you are absolutely sure that you trust the BIOS
1245 to get all its memory reservations and usages right.
1247 If you have doubts about the BIOS (e.g. suspend/resume does not
1248 work or there's kernel crashes after certain hardware hotplug
1249 events) and it's not AMI or Phoenix, then you might want to enable
1250 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1251 corruption patterns.
1255 config MATH_EMULATION
1257 prompt "Math emulation" if X86_32
1259 Linux can emulate a math coprocessor (used for floating point
1260 operations) if you don't have one. 486DX and Pentium processors have
1261 a math coprocessor built in, 486SX and 386 do not, unless you added
1262 a 487DX or 387, respectively. (The messages during boot time can
1263 give you some hints here ["man dmesg"].) Everyone needs either a
1264 coprocessor or this emulation.
1266 If you don't have a math coprocessor, you need to say Y here; if you
1267 say Y here even though you have a coprocessor, the coprocessor will
1268 be used nevertheless. (This behavior can be changed with the kernel
1269 command line option "no387", which comes handy if your coprocessor
1270 is broken. Try "man bootparam" or see the documentation of your boot
1271 loader (lilo or loadlin) about how to pass options to the kernel at
1272 boot time.) This means that it is a good idea to say Y here if you
1273 intend to use this kernel on different machines.
1275 More information about the internals of the Linux math coprocessor
1276 emulation can be found in <file:arch/x86/math-emu/README>.
1278 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1279 kernel, it won't hurt.
1282 bool "MTRR (Memory Type Range Register) support"
1284 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1285 the Memory Type Range Registers (MTRRs) may be used to control
1286 processor access to memory ranges. This is most useful if you have
1287 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1288 allows bus write transfers to be combined into a larger transfer
1289 before bursting over the PCI/AGP bus. This can increase performance
1290 of image write operations 2.5 times or more. Saying Y here creates a
1291 /proc/mtrr file which may be used to manipulate your processor's
1292 MTRRs. Typically the X server should use this.
1294 This code has a reasonably generic interface so that similar
1295 control registers on other processors can be easily supported
1298 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1299 Registers (ARRs) which provide a similar functionality to MTRRs. For
1300 these, the ARRs are used to emulate the MTRRs.
1301 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1302 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1303 write-combining. All of these processors are supported by this code
1304 and it makes sense to say Y here if you have one of them.
1306 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1307 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1308 can lead to all sorts of problems, so it's good to say Y here.
1310 You can safely say Y even if your machine doesn't have MTRRs, you'll
1311 just add about 9 KB to your kernel.
1313 See <file:Documentation/x86/mtrr.txt> for more information.
1315 config MTRR_SANITIZER
1317 prompt "MTRR cleanup support"
1320 Convert MTRR layout from continuous to discrete, so X drivers can
1321 add writeback entries.
1323 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1324 The largest mtrr entry size for a continuous block can be set with
1329 config MTRR_SANITIZER_ENABLE_DEFAULT
1330 int "MTRR cleanup enable value (0-1)"
1333 depends on MTRR_SANITIZER
1335 Enable mtrr cleanup default value
1337 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1338 int "MTRR cleanup spare reg num (0-7)"
1341 depends on MTRR_SANITIZER
1343 mtrr cleanup spare entries default, it can be changed via
1344 mtrr_spare_reg_nr=N on the kernel command line.
1348 prompt "x86 PAT support"
1351 Use PAT attributes to setup page level cache control.
1353 PATs are the modern equivalents of MTRRs and are much more
1354 flexible than MTRRs.
1356 Say N here if you see bootup problems (boot crash, boot hang,
1357 spontaneous reboots) or a non-working video driver.
1362 bool "EFI runtime service support"
1365 This enables the kernel to use EFI runtime services that are
1366 available (such as the EFI variable services).
1368 This option is only useful on systems that have EFI firmware.
1369 In addition, you should use the latest ELILO loader available
1370 at <http://elilo.sourceforge.net> in order to take advantage
1371 of EFI runtime services. However, even with this option, the
1372 resultant kernel should continue to boot on existing non-EFI
1377 prompt "Enable seccomp to safely compute untrusted bytecode"
1379 This kernel feature is useful for number crunching applications
1380 that may need to compute untrusted bytecode during their
1381 execution. By using pipes or other transports made available to
1382 the process as file descriptors supporting the read/write
1383 syscalls, it's possible to isolate those applications in
1384 their own address space using seccomp. Once seccomp is
1385 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1386 and the task is only allowed to execute a few safe syscalls
1387 defined by each seccomp mode.
1389 If unsure, say Y. Only embedded should say N here.
1391 config CC_STACKPROTECTOR_ALL
1394 config CC_STACKPROTECTOR
1395 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1396 select CC_STACKPROTECTOR_ALL
1398 This option turns on the -fstack-protector GCC feature. This
1399 feature puts, at the beginning of functions, a canary value on
1400 the stack just before the return address, and validates
1401 the value just before actually returning. Stack based buffer
1402 overflows (that need to overwrite this return address) now also
1403 overwrite the canary, which gets detected and the attack is then
1404 neutralized via a kernel panic.
1406 This feature requires gcc version 4.2 or above, or a distribution
1407 gcc with the feature backported. Older versions are automatically
1408 detected and for those versions, this configuration option is
1409 ignored. (and a warning is printed during bootup)
1411 source kernel/Kconfig.hz
1414 bool "kexec system call"
1416 kexec is a system call that implements the ability to shutdown your
1417 current kernel, and to start another kernel. It is like a reboot
1418 but it is independent of the system firmware. And like a reboot
1419 you can start any kernel with it, not just Linux.
1421 The name comes from the similarity to the exec system call.
1423 It is an ongoing process to be certain the hardware in a machine
1424 is properly shutdown, so do not be surprised if this code does not
1425 initially work for you. It may help to enable device hotplugging
1426 support. As of this writing the exact hardware interface is
1427 strongly in flux, so no good recommendation can be made.
1430 bool "kernel crash dumps"
1431 depends on X86_64 || (X86_32 && HIGHMEM)
1433 Generate crash dump after being started by kexec.
1434 This should be normally only set in special crash dump kernels
1435 which are loaded in the main kernel with kexec-tools into
1436 a specially reserved region and then later executed after
1437 a crash by kdump/kexec. The crash dump kernel must be compiled
1438 to a memory address not used by the main kernel or BIOS using
1439 PHYSICAL_START, or it must be built as a relocatable image
1440 (CONFIG_RELOCATABLE=y).
1441 For more details see Documentation/kdump/kdump.txt
1444 bool "kexec jump (EXPERIMENTAL)"
1445 depends on EXPERIMENTAL
1446 depends on KEXEC && HIBERNATION
1448 Jump between original kernel and kexeced kernel and invoke
1449 code in physical address mode via KEXEC
1451 config PHYSICAL_START
1452 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1453 default "0x1000000" if X86_NUMAQ
1454 default "0x200000" if X86_64
1457 This gives the physical address where the kernel is loaded.
1459 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1460 bzImage will decompress itself to above physical address and
1461 run from there. Otherwise, bzImage will run from the address where
1462 it has been loaded by the boot loader and will ignore above physical
1465 In normal kdump cases one does not have to set/change this option
1466 as now bzImage can be compiled as a completely relocatable image
1467 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1468 address. This option is mainly useful for the folks who don't want
1469 to use a bzImage for capturing the crash dump and want to use a
1470 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1471 to be specifically compiled to run from a specific memory area
1472 (normally a reserved region) and this option comes handy.
1474 So if you are using bzImage for capturing the crash dump, leave
1475 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1476 Otherwise if you plan to use vmlinux for capturing the crash dump
1477 change this value to start of the reserved region (Typically 16MB
1478 0x1000000). In other words, it can be set based on the "X" value as
1479 specified in the "crashkernel=YM@XM" command line boot parameter
1480 passed to the panic-ed kernel. Typically this parameter is set as
1481 crashkernel=64M@16M. Please take a look at
1482 Documentation/kdump/kdump.txt for more details about crash dumps.
1484 Usage of bzImage for capturing the crash dump is recommended as
1485 one does not have to build two kernels. Same kernel can be used
1486 as production kernel and capture kernel. Above option should have
1487 gone away after relocatable bzImage support is introduced. But it
1488 is present because there are users out there who continue to use
1489 vmlinux for dump capture. This option should go away down the
1492 Don't change this unless you know what you are doing.
1495 bool "Build a relocatable kernel (EXPERIMENTAL)"
1496 depends on EXPERIMENTAL
1498 This builds a kernel image that retains relocation information
1499 so it can be loaded someplace besides the default 1MB.
1500 The relocations tend to make the kernel binary about 10% larger,
1501 but are discarded at runtime.
1503 One use is for the kexec on panic case where the recovery kernel
1504 must live at a different physical address than the primary
1507 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1508 it has been loaded at and the compile time physical address
1509 (CONFIG_PHYSICAL_START) is ignored.
1511 config PHYSICAL_ALIGN
1513 prompt "Alignment value to which kernel should be aligned" if X86_32
1514 default "0x100000" if X86_32
1515 default "0x200000" if X86_64
1516 range 0x2000 0x400000
1518 This value puts the alignment restrictions on physical address
1519 where kernel is loaded and run from. Kernel is compiled for an
1520 address which meets above alignment restriction.
1522 If bootloader loads the kernel at a non-aligned address and
1523 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1524 address aligned to above value and run from there.
1526 If bootloader loads the kernel at a non-aligned address and
1527 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1528 load address and decompress itself to the address it has been
1529 compiled for and run from there. The address for which kernel is
1530 compiled already meets above alignment restrictions. Hence the
1531 end result is that kernel runs from a physical address meeting
1532 above alignment restrictions.
1534 Don't change this unless you know what you are doing.
1537 bool "Support for hot-pluggable CPUs"
1538 depends on SMP && HOTPLUG
1540 Say Y here to allow turning CPUs off and on. CPUs can be
1541 controlled through /sys/devices/system/cpu.
1542 ( Note: power management support will enable this option
1543 automatically on SMP systems. )
1544 Say N if you want to disable CPU hotplug.
1548 prompt "Compat VDSO support"
1549 depends on X86_32 || IA32_EMULATION
1551 Map the 32-bit VDSO to the predictable old-style address too.
1553 Say N here if you are running a sufficiently recent glibc
1554 version (2.3.3 or later), to remove the high-mapped
1555 VDSO mapping and to exclusively use the randomized VDSO.
1560 bool "Built-in kernel command line"
1563 Allow for specifying boot arguments to the kernel at
1564 build time. On some systems (e.g. embedded ones), it is
1565 necessary or convenient to provide some or all of the
1566 kernel boot arguments with the kernel itself (that is,
1567 to not rely on the boot loader to provide them.)
1569 To compile command line arguments into the kernel,
1570 set this option to 'Y', then fill in the
1571 the boot arguments in CONFIG_CMDLINE.
1573 Systems with fully functional boot loaders (i.e. non-embedded)
1574 should leave this option set to 'N'.
1577 string "Built-in kernel command string"
1578 depends on CMDLINE_BOOL
1581 Enter arguments here that should be compiled into the kernel
1582 image and used at boot time. If the boot loader provides a
1583 command line at boot time, it is appended to this string to
1584 form the full kernel command line, when the system boots.
1586 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1587 change this behavior.
1589 In most cases, the command line (whether built-in or provided
1590 by the boot loader) should specify the device for the root
1593 config CMDLINE_OVERRIDE
1594 bool "Built-in command line overrides boot loader arguments"
1596 depends on CMDLINE_BOOL
1598 Set this option to 'Y' to have the kernel ignore the boot loader
1599 command line, and use ONLY the built-in command line.
1601 This is used to work around broken boot loaders. This should
1602 be set to 'N' under normal conditions.
1606 config ARCH_ENABLE_MEMORY_HOTPLUG
1608 depends on X86_64 || (X86_32 && HIGHMEM)
1610 config ARCH_ENABLE_MEMORY_HOTREMOVE
1612 depends on MEMORY_HOTPLUG
1614 config HAVE_ARCH_EARLY_PFN_TO_NID
1618 menu "Power management and ACPI options"
1620 config ARCH_HIBERNATION_HEADER
1622 depends on X86_64 && HIBERNATION
1624 source "kernel/power/Kconfig"
1626 source "drivers/acpi/Kconfig"
1631 depends on APM || APM_MODULE
1634 tristate "APM (Advanced Power Management) BIOS support"
1635 depends on X86_32 && PM_SLEEP
1637 APM is a BIOS specification for saving power using several different
1638 techniques. This is mostly useful for battery powered laptops with
1639 APM compliant BIOSes. If you say Y here, the system time will be
1640 reset after a RESUME operation, the /proc/apm device will provide
1641 battery status information, and user-space programs will receive
1642 notification of APM "events" (e.g. battery status change).
1644 If you select "Y" here, you can disable actual use of the APM
1645 BIOS by passing the "apm=off" option to the kernel at boot time.
1647 Note that the APM support is almost completely disabled for
1648 machines with more than one CPU.
1650 In order to use APM, you will need supporting software. For location
1651 and more information, read <file:Documentation/power/pm.txt> and the
1652 Battery Powered Linux mini-HOWTO, available from
1653 <http://www.tldp.org/docs.html#howto>.
1655 This driver does not spin down disk drives (see the hdparm(8)
1656 manpage ("man 8 hdparm") for that), and it doesn't turn off
1657 VESA-compliant "green" monitors.
1659 This driver does not support the TI 4000M TravelMate and the ACER
1660 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1661 desktop machines also don't have compliant BIOSes, and this driver
1662 may cause those machines to panic during the boot phase.
1664 Generally, if you don't have a battery in your machine, there isn't
1665 much point in using this driver and you should say N. If you get
1666 random kernel OOPSes or reboots that don't seem to be related to
1667 anything, try disabling/enabling this option (or disabling/enabling
1670 Some other things you should try when experiencing seemingly random,
1673 1) make sure that you have enough swap space and that it is
1675 2) pass the "no-hlt" option to the kernel
1676 3) switch on floating point emulation in the kernel and pass
1677 the "no387" option to the kernel
1678 4) pass the "floppy=nodma" option to the kernel
1679 5) pass the "mem=4M" option to the kernel (thereby disabling
1680 all but the first 4 MB of RAM)
1681 6) make sure that the CPU is not over clocked.
1682 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1683 8) disable the cache from your BIOS settings
1684 9) install a fan for the video card or exchange video RAM
1685 10) install a better fan for the CPU
1686 11) exchange RAM chips
1687 12) exchange the motherboard.
1689 To compile this driver as a module, choose M here: the
1690 module will be called apm.
1694 config APM_IGNORE_USER_SUSPEND
1695 bool "Ignore USER SUSPEND"
1697 This option will ignore USER SUSPEND requests. On machines with a
1698 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1699 series notebooks, it is necessary to say Y because of a BIOS bug.
1701 config APM_DO_ENABLE
1702 bool "Enable PM at boot time"
1704 Enable APM features at boot time. From page 36 of the APM BIOS
1705 specification: "When disabled, the APM BIOS does not automatically
1706 power manage devices, enter the Standby State, enter the Suspend
1707 State, or take power saving steps in response to CPU Idle calls."
1708 This driver will make CPU Idle calls when Linux is idle (unless this
1709 feature is turned off -- see "Do CPU IDLE calls", below). This
1710 should always save battery power, but more complicated APM features
1711 will be dependent on your BIOS implementation. You may need to turn
1712 this option off if your computer hangs at boot time when using APM
1713 support, or if it beeps continuously instead of suspending. Turn
1714 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1715 T400CDT. This is off by default since most machines do fine without
1719 bool "Make CPU Idle calls when idle"
1721 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1722 On some machines, this can activate improved power savings, such as
1723 a slowed CPU clock rate, when the machine is idle. These idle calls
1724 are made after the idle loop has run for some length of time (e.g.,
1725 333 mS). On some machines, this will cause a hang at boot time or
1726 whenever the CPU becomes idle. (On machines with more than one CPU,
1727 this option does nothing.)
1729 config APM_DISPLAY_BLANK
1730 bool "Enable console blanking using APM"
1732 Enable console blanking using the APM. Some laptops can use this to
1733 turn off the LCD backlight when the screen blanker of the Linux
1734 virtual console blanks the screen. Note that this is only used by
1735 the virtual console screen blanker, and won't turn off the backlight
1736 when using the X Window system. This also doesn't have anything to
1737 do with your VESA-compliant power-saving monitor. Further, this
1738 option doesn't work for all laptops -- it might not turn off your
1739 backlight at all, or it might print a lot of errors to the console,
1740 especially if you are using gpm.
1742 config APM_ALLOW_INTS
1743 bool "Allow interrupts during APM BIOS calls"
1745 Normally we disable external interrupts while we are making calls to
1746 the APM BIOS as a measure to lessen the effects of a badly behaving
1747 BIOS implementation. The BIOS should reenable interrupts if it
1748 needs to. Unfortunately, some BIOSes do not -- especially those in
1749 many of the newer IBM Thinkpads. If you experience hangs when you
1750 suspend, try setting this to Y. Otherwise, say N.
1754 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1756 source "drivers/cpuidle/Kconfig"
1758 source "drivers/idle/Kconfig"
1763 menu "Bus options (PCI etc.)"
1768 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1770 Find out whether you have a PCI motherboard. PCI is the name of a
1771 bus system, i.e. the way the CPU talks to the other stuff inside
1772 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1773 VESA. If you have PCI, say Y, otherwise N.
1776 prompt "PCI access mode"
1777 depends on X86_32 && PCI
1780 On PCI systems, the BIOS can be used to detect the PCI devices and
1781 determine their configuration. However, some old PCI motherboards
1782 have BIOS bugs and may crash if this is done. Also, some embedded
1783 PCI-based systems don't have any BIOS at all. Linux can also try to
1784 detect the PCI hardware directly without using the BIOS.
1786 With this option, you can specify how Linux should detect the
1787 PCI devices. If you choose "BIOS", the BIOS will be used,
1788 if you choose "Direct", the BIOS won't be used, and if you
1789 choose "MMConfig", then PCI Express MMCONFIG will be used.
1790 If you choose "Any", the kernel will try MMCONFIG, then the
1791 direct access method and falls back to the BIOS if that doesn't
1792 work. If unsure, go with the default, which is "Any".
1797 config PCI_GOMMCONFIG
1814 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1816 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1819 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1823 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1827 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1834 bool "Support mmconfig PCI config space access"
1835 depends on X86_64 && PCI && ACPI
1838 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1839 depends on PCI_MSI && ACPI && EXPERIMENTAL
1841 DMA remapping (DMAR) devices support enables independent address
1842 translations for Direct Memory Access (DMA) from devices.
1843 These DMA remapping devices are reported via ACPI tables
1844 and include PCI device scope covered by these DMA
1847 config DMAR_DEFAULT_ON
1849 prompt "Enable DMA Remapping Devices by default"
1852 Selecting this option will enable a DMAR device at boot time if
1853 one is found. If this option is not selected, DMAR support can
1854 be enabled by passing intel_iommu=on to the kernel. It is
1855 recommended you say N here while the DMAR code remains
1860 prompt "Support for Graphics workaround"
1863 Current Graphics drivers tend to use physical address
1864 for DMA and avoid using DMA APIs. Setting this config
1865 option permits the IOMMU driver to set a unity map for
1866 all the OS-visible memory. Hence the driver can continue
1867 to use physical addresses for DMA.
1869 config DMAR_FLOPPY_WA
1873 Floppy disk drivers are know to bypass DMA API calls
1874 thereby failing to work when IOMMU is enabled. This
1875 workaround will setup a 1:1 mapping for the first
1876 16M to make floppy (an ISA device) work.
1879 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1880 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1882 Supports Interrupt remapping for IO-APIC and MSI devices.
1883 To use x2apic mode in the CPU's which support x2APIC enhancements or
1884 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1886 source "drivers/pci/pcie/Kconfig"
1888 source "drivers/pci/Kconfig"
1890 # x86_64 have no ISA slots, but do have ISA-style DMA.
1899 Find out whether you have ISA slots on your motherboard. ISA is the
1900 name of a bus system, i.e. the way the CPU talks to the other stuff
1901 inside your box. Other bus systems are PCI, EISA, MicroChannel
1902 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1903 newer boards don't support it. If you have ISA, say Y, otherwise N.
1909 The Extended Industry Standard Architecture (EISA) bus was
1910 developed as an open alternative to the IBM MicroChannel bus.
1912 The EISA bus provided some of the features of the IBM MicroChannel
1913 bus while maintaining backward compatibility with cards made for
1914 the older ISA bus. The EISA bus saw limited use between 1988 and
1915 1995 when it was made obsolete by the PCI bus.
1917 Say Y here if you are building a kernel for an EISA-based machine.
1921 source "drivers/eisa/Kconfig"
1926 MicroChannel Architecture is found in some IBM PS/2 machines and
1927 laptops. It is a bus system similar to PCI or ISA. See
1928 <file:Documentation/mca.txt> (and especially the web page given
1929 there) before attempting to build an MCA bus kernel.
1931 source "drivers/mca/Kconfig"
1934 tristate "NatSemi SCx200 support"
1936 This provides basic support for National Semiconductor's
1937 (now AMD's) Geode processors. The driver probes for the
1938 PCI-IDs of several on-chip devices, so its a good dependency
1939 for other scx200_* drivers.
1941 If compiled as a module, the driver is named scx200.
1943 config SCx200HR_TIMER
1944 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1945 depends on SCx200 && GENERIC_TIME
1948 This driver provides a clocksource built upon the on-chip
1949 27MHz high-resolution timer. Its also a workaround for
1950 NSC Geode SC-1100's buggy TSC, which loses time when the
1951 processor goes idle (as is done by the scheduler). The
1952 other workaround is idle=poll boot option.
1954 config GEODE_MFGPT_TIMER
1956 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1957 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1959 This driver provides a clock event source based on the MFGPT
1960 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1961 MFGPTs have a better resolution and max interval than the
1962 generic PIT, and are suitable for use as high-res timers.
1965 bool "One Laptop Per Child support"
1968 Add support for detecting the unique features of the OLPC
1975 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1977 source "drivers/pcmcia/Kconfig"
1979 source "drivers/pci/hotplug/Kconfig"
1984 menu "Executable file formats / Emulations"
1986 source "fs/Kconfig.binfmt"
1988 config IA32_EMULATION
1989 bool "IA32 Emulation"
1991 select COMPAT_BINFMT_ELF
1993 Include code to run 32-bit programs under a 64-bit kernel. You should
1994 likely turn this on, unless you're 100% sure that you don't have any
1995 32-bit programs left.
1998 tristate "IA32 a.out support"
1999 depends on IA32_EMULATION
2001 Support old a.out binaries in the 32bit emulation.
2005 depends on IA32_EMULATION
2007 config COMPAT_FOR_U64_ALIGNMENT
2011 config SYSVIPC_COMPAT
2013 depends on COMPAT && SYSVIPC
2018 config HAVE_ATOMIC_IOMAP
2022 source "net/Kconfig"
2024 source "drivers/Kconfig"
2026 source "drivers/firmware/Kconfig"
2030 source "arch/x86/Kconfig.debug"
2032 source "security/Kconfig"
2034 source "crypto/Kconfig"
2036 source "arch/x86/kvm/Kconfig"
2038 source "lib/Kconfig"
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