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 "elf32-i386" if X86_32
53 default "elf64-x86-64" if X86_64
57 default "arch/x86/configs/i386_defconfig" if X86_32
58 default "arch/x86/configs/x86_64_defconfig" if X86_64
63 config GENERIC_CMOS_UPDATE
66 config CLOCKSOURCE_WATCHDOG
69 config GENERIC_CLOCKEVENTS
72 config GENERIC_CLOCKEVENTS_BROADCAST
74 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
76 config LOCKDEP_SUPPORT
79 config STACKTRACE_SUPPORT
82 config HAVE_LATENCYTOP_SUPPORT
85 config FAST_CMPXCHG_LOCAL
98 config GENERIC_ISA_DMA
107 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
109 config GENERIC_BUG_RELATIVE_POINTERS
112 config GENERIC_HWEIGHT
118 config ARCH_MAY_HAVE_PC_FDC
121 config RWSEM_GENERIC_SPINLOCK
124 config RWSEM_XCHGADD_ALGORITHM
127 config ARCH_HAS_CPU_IDLE_WAIT
130 config GENERIC_CALIBRATE_DELAY
133 config GENERIC_TIME_VSYSCALL
137 config ARCH_HAS_CPU_RELAX
140 config ARCH_HAS_DEFAULT_IDLE
143 config ARCH_HAS_CACHE_LINE_SIZE
146 config HAVE_SETUP_PER_CPU_AREA
149 config HAVE_DYNAMIC_PER_CPU_AREA
152 config HAVE_CPUMASK_OF_CPU_MAP
155 config ARCH_HIBERNATION_POSSIBLE
158 config ARCH_SUSPEND_POSSIBLE
165 config ARCH_POPULATES_NODE_MAP
172 config ARCH_SUPPORTS_OPTIMIZED_INLINING
175 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
178 # Use the generic interrupt handling code in kernel/irq/:
179 config GENERIC_HARDIRQS
183 config GENERIC_HARDIRQS_NO__DO_IRQ
186 config GENERIC_IRQ_PROBE
190 config GENERIC_PENDING_IRQ
192 depends on GENERIC_HARDIRQS && SMP
195 config USE_GENERIC_SMP_HELPERS
201 depends on X86_32 && SMP
205 depends on X86_64 && SMP
212 config X86_TRAMPOLINE
214 depends on SMP || (64BIT && ACPI_SLEEP)
217 config X86_32_LAZY_GS
219 depends on X86_32 && !CC_STACKPROTECTOR
223 source "init/Kconfig"
224 source "kernel/Kconfig.freezer"
226 menu "Processor type and features"
228 source "kernel/time/Kconfig"
231 bool "Symmetric multi-processing support"
233 This enables support for systems with more than one CPU. If you have
234 a system with only one CPU, like most personal computers, say N. If
235 you have a system with more than one CPU, say Y.
237 If you say N here, the kernel will run on single and multiprocessor
238 machines, but will use only one CPU of a multiprocessor machine. If
239 you say Y here, the kernel will run on many, but not all,
240 singleprocessor machines. On a singleprocessor machine, the kernel
241 will run faster if you say N here.
243 Note that if you say Y here and choose architecture "586" or
244 "Pentium" under "Processor family", the kernel will not work on 486
245 architectures. Similarly, multiprocessor kernels for the "PPro"
246 architecture may not work on all Pentium based boards.
248 People using multiprocessor machines who say Y here should also say
249 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
250 Management" code will be disabled if you say Y here.
252 See also <file:Documentation/i386/IO-APIC.txt>,
253 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
254 <http://www.tldp.org/docs.html#howto>.
256 If you don't know what to do here, say N.
259 bool "Support x2apic"
260 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
262 This enables x2apic support on CPUs that have this feature.
264 This allows 32-bit apic IDs (so it can support very large systems),
265 and accesses the local apic via MSRs not via mmio.
267 If you don't know what to do here, say N.
270 bool "Support sparse irq numbering"
271 depends on PCI_MSI || HT_IRQ
273 This enables support for sparse irqs. This is useful for distro
274 kernels that want to define a high CONFIG_NR_CPUS value but still
275 want to have low kernel memory footprint on smaller machines.
277 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
278 out the irq_desc[] array in a more NUMA-friendly way. )
280 If you don't know what to do here, say N.
284 depends on SPARSE_IRQ && NUMA
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
357 depends on X86_X2APIC
359 This option is needed in order to support SGI Ultraviolet systems.
360 If you don't have one of these, you should say N here.
362 # Following is an alphabetically sorted list of 32 bit extended platforms
363 # Please maintain the alphabetic order if and when there are additions
368 depends on X86_EXTENDED_PLATFORM
370 Select this for an AMD Elan processor.
372 Do not use this option for K6/Athlon/Opteron processors!
374 If unsure, choose "PC-compatible" instead.
377 bool "RDC R-321x SoC"
379 depends on X86_EXTENDED_PLATFORM
381 select X86_REBOOTFIXUPS
383 This option is needed for RDC R-321x system-on-chip, also known
385 If you don't have one of these chips, you should say N here.
387 config X86_32_NON_STANDARD
388 bool "Support non-standard 32-bit SMP architectures"
389 depends on X86_32 && SMP
390 depends on X86_EXTENDED_PLATFORM
392 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
393 subarchitectures. It is intended for a generic binary kernel.
394 if you select them all, kernel will probe it one by one. and will
397 # Alphabetically sorted list of Non standard 32 bit platforms
400 bool "NUMAQ (IBM/Sequent)"
401 depends on X86_32_NON_STANDARD
405 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
406 NUMA multiquad box. This changes the way that processors are
407 bootstrapped, and uses Clustered Logical APIC addressing mode instead
408 of Flat Logical. You will need a new lynxer.elf file to flash your
409 firmware with - send email to <Martin.Bligh@us.ibm.com>.
412 bool "SGI 320/540 (Visual Workstation)"
413 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
414 depends on X86_32_NON_STANDARD
416 The SGI Visual Workstation series is an IA32-based workstation
417 based on SGI systems chips with some legacy PC hardware attached.
419 Say Y here to create a kernel to run on the SGI 320 or 540.
421 A kernel compiled for the Visual Workstation will run on general
422 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
425 bool "Summit/EXA (IBM x440)"
426 depends on X86_32_NON_STANDARD
428 This option is needed for IBM systems that use the Summit/EXA chipset.
429 In particular, it is needed for the x440.
432 bool "Unisys ES7000 IA32 series"
433 depends on X86_32_NON_STANDARD && X86_BIGSMP
435 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
436 supposed to run on an IA32-based Unisys ES7000 system.
438 config SCHED_OMIT_FRAME_POINTER
440 prompt "Single-depth WCHAN output"
443 Calculate simpler /proc/<PID>/wchan values. If this option
444 is disabled then wchan values will recurse back to the
445 caller function. This provides more accurate wchan values,
446 at the expense of slightly more scheduling overhead.
448 If in doubt, say "Y".
450 menuconfig PARAVIRT_GUEST
451 bool "Paravirtualized guest support"
453 Say Y here to get to see options related to running Linux under
454 various hypervisors. This option alone does not add any kernel code.
456 If you say N, all options in this submenu will be skipped and disabled.
460 source "arch/x86/xen/Kconfig"
463 bool "VMI Guest support"
467 VMI provides a paravirtualized interface to the VMware ESX server
468 (it could be used by other hypervisors in theory too, but is not
469 at the moment), by linking the kernel to a GPL-ed ROM module
470 provided by the hypervisor.
473 bool "KVM paravirtualized clock"
475 select PARAVIRT_CLOCK
477 Turning on this option will allow you to run a paravirtualized clock
478 when running over the KVM hypervisor. Instead of relying on a PIT
479 (or probably other) emulation by the underlying device model, the host
480 provides the guest with timing infrastructure such as time of day, and
484 bool "KVM Guest support"
487 This option enables various optimizations for running under the KVM
490 source "arch/x86/lguest/Kconfig"
493 bool "Enable paravirtualization code"
495 This changes the kernel so it can modify itself when it is run
496 under a hypervisor, potentially improving performance significantly
497 over full virtualization. However, when run without a hypervisor
498 the kernel is theoretically slower and slightly larger.
500 config PARAVIRT_SPINLOCKS
501 bool "Paravirtualization layer for spinlocks"
502 depends on PARAVIRT && SMP && EXPERIMENTAL
504 Paravirtualized spinlocks allow a pvops backend to replace the
505 spinlock implementation with something virtualization-friendly
506 (for example, block the virtual CPU rather than spinning).
508 Unfortunately the downside is an up to 5% performance hit on
509 native kernels, with various workloads.
511 If you are unsure how to answer this question, answer N.
513 config PARAVIRT_CLOCK
519 config PARAVIRT_DEBUG
520 bool "paravirt-ops debugging"
521 depends on PARAVIRT && DEBUG_KERNEL
523 Enable to debug paravirt_ops internals. Specifically, BUG if
524 a paravirt_op is missing when it is called.
529 This option adds a kernel parameter 'memtest', which allows memtest
531 memtest=0, mean disabled; -- default
532 memtest=1, mean do 1 test pattern;
534 memtest=4, mean do 4 test patterns.
535 If you are unsure how to answer this question, answer N.
537 config X86_SUMMIT_NUMA
539 depends on X86_32 && NUMA && X86_32_NON_STANDARD
541 config X86_CYCLONE_TIMER
543 depends on X86_32_NON_STANDARD
545 source "arch/x86/Kconfig.cpu"
549 prompt "HPET Timer Support" if X86_32
551 Use the IA-PC HPET (High Precision Event Timer) to manage
552 time in preference to the PIT and RTC, if a HPET is
554 HPET is the next generation timer replacing legacy 8254s.
555 The HPET provides a stable time base on SMP
556 systems, unlike the TSC, but it is more expensive to access,
557 as it is off-chip. You can find the HPET spec at
558 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
560 You can safely choose Y here. However, HPET will only be
561 activated if the platform and the BIOS support this feature.
562 Otherwise the 8254 will be used for timing services.
564 Choose N to continue using the legacy 8254 timer.
566 config HPET_EMULATE_RTC
568 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
570 # Mark as embedded because too many people got it wrong.
571 # The code disables itself when not needed.
574 bool "Enable DMI scanning" if EMBEDDED
576 Enabled scanning of DMI to identify machine quirks. Say Y
577 here unless you have verified that your setup is not
578 affected by entries in the DMI blacklist. Required by PNP
582 bool "GART IOMMU support" if EMBEDDED
586 depends on X86_64 && PCI
588 Support for full DMA access of devices with 32bit memory access only
589 on systems with more than 3GB. This is usually needed for USB,
590 sound, many IDE/SATA chipsets and some other devices.
591 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
592 based hardware IOMMU and a software bounce buffer based IOMMU used
593 on Intel systems and as fallback.
594 The code is only active when needed (enough memory and limited
595 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
599 bool "IBM Calgary IOMMU support"
601 depends on X86_64 && PCI && EXPERIMENTAL
603 Support for hardware IOMMUs in IBM's xSeries x366 and x460
604 systems. Needed to run systems with more than 3GB of memory
605 properly with 32-bit PCI devices that do not support DAC
606 (Double Address Cycle). Calgary also supports bus level
607 isolation, where all DMAs pass through the IOMMU. This
608 prevents them from going anywhere except their intended
609 destination. This catches hard-to-find kernel bugs and
610 mis-behaving drivers and devices that do not use the DMA-API
611 properly to set up their DMA buffers. The IOMMU can be
612 turned off at boot time with the iommu=off parameter.
613 Normally the kernel will make the right choice by itself.
616 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
618 prompt "Should Calgary be enabled by default?"
619 depends on CALGARY_IOMMU
621 Should Calgary be enabled by default? if you choose 'y', Calgary
622 will be used (if it exists). If you choose 'n', Calgary will not be
623 used even if it exists. If you choose 'n' and would like to use
624 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
628 bool "AMD IOMMU support"
631 depends on X86_64 && PCI && ACPI
633 With this option you can enable support for AMD IOMMU hardware in
634 your system. An IOMMU is a hardware component which provides
635 remapping of DMA memory accesses from devices. With an AMD IOMMU you
636 can isolate the the DMA memory of different devices and protect the
637 system from misbehaving device drivers or hardware.
639 You can find out if your system has an AMD IOMMU if you look into
640 your BIOS for an option to enable it or if you have an IVRS ACPI
643 config AMD_IOMMU_STATS
644 bool "Export AMD IOMMU statistics to debugfs"
648 This option enables code in the AMD IOMMU driver to collect various
649 statistics about whats happening in the driver and exports that
650 information to userspace via debugfs.
653 # need this always selected by IOMMU for the VIA workaround
657 Support for software bounce buffers used on x86-64 systems
658 which don't have a hardware IOMMU (e.g. the current generation
659 of Intel's x86-64 CPUs). Using this PCI devices which can only
660 access 32-bits of memory can be used on systems with more than
661 3 GB of memory. If unsure, say Y.
664 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
667 def_bool (AMD_IOMMU || DMAR)
670 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
671 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
672 select CPUMASK_OFFSTACK
675 Configure maximum number of CPUS and NUMA Nodes for this architecture.
679 int "Maximum number of CPUs" if SMP && !MAXSMP
680 range 2 8 if SMP && X86_32 && !X86_BIGSMP
681 range 2 512 if SMP && !MAXSMP
683 default "4096" if MAXSMP
684 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
687 This allows you to specify the maximum number of CPUs which this
688 kernel will support. The maximum supported value is 512 and the
689 minimum value which makes sense is 2.
691 This is purely to save memory - each supported CPU adds
692 approximately eight kilobytes to the kernel image.
695 bool "SMT (Hyperthreading) scheduler support"
698 SMT scheduler support improves the CPU scheduler's decision making
699 when dealing with Intel Pentium 4 chips with HyperThreading at a
700 cost of slightly increased overhead in some places. If unsure say
705 prompt "Multi-core scheduler support"
708 Multi-core scheduler support improves the CPU scheduler's decision
709 making when dealing with multi-core CPU chips at a cost of slightly
710 increased overhead in some places. If unsure say N here.
712 source "kernel/Kconfig.preempt"
715 bool "Local APIC support on uniprocessors"
716 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
718 A local APIC (Advanced Programmable Interrupt Controller) is an
719 integrated interrupt controller in the CPU. If you have a single-CPU
720 system which has a processor with a local APIC, you can say Y here to
721 enable and use it. If you say Y here even though your machine doesn't
722 have a local APIC, then the kernel will still run with no slowdown at
723 all. The local APIC supports CPU-generated self-interrupts (timer,
724 performance counters), and the NMI watchdog which detects hard
728 bool "IO-APIC support on uniprocessors"
729 depends on X86_UP_APIC
731 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
732 SMP-capable replacement for PC-style interrupt controllers. Most
733 SMP systems and many recent uniprocessor systems have one.
735 If you have a single-CPU system with an IO-APIC, you can say Y here
736 to use it. If you say Y here even though your machine doesn't have
737 an IO-APIC, then the kernel will still run with no slowdown at all.
739 config X86_LOCAL_APIC
741 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
742 select HAVE_PERF_COUNTERS if (!M386 && !M486)
746 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
748 config X86_VISWS_APIC
750 depends on X86_32 && X86_VISWS
752 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
753 bool "Reroute for broken boot IRQs"
755 depends on X86_IO_APIC
757 This option enables a workaround that fixes a source of
758 spurious interrupts. This is recommended when threaded
759 interrupt handling is used on systems where the generation of
760 superfluous "boot interrupts" cannot be disabled.
762 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
763 entry in the chipset's IO-APIC is masked (as, e.g. the RT
764 kernel does during interrupt handling). On chipsets where this
765 boot IRQ generation cannot be disabled, this workaround keeps
766 the original IRQ line masked so that only the equivalent "boot
767 IRQ" is delivered to the CPUs. The workaround also tells the
768 kernel to set up the IRQ handler on the boot IRQ line. In this
769 way only one interrupt is delivered to the kernel. Otherwise
770 the spurious second interrupt may cause the kernel to bring
771 down (vital) interrupt lines.
773 Only affects "broken" chipsets. Interrupt sharing may be
774 increased on these systems.
777 bool "Machine Check Exception"
779 Machine Check Exception support allows the processor to notify the
780 kernel if it detects a problem (e.g. overheating, component failure).
781 The action the kernel takes depends on the severity of the problem,
782 ranging from a warning message on the console, to halting the machine.
783 Your processor must be a Pentium or newer to support this - check the
784 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
785 have a design flaw which leads to false MCE events - hence MCE is
786 disabled on all P5 processors, unless explicitly enabled with "mce"
787 as a boot argument. Similarly, if MCE is built in and creates a
788 problem on some new non-standard machine, you can boot with "nomce"
789 to disable it. MCE support simply ignores non-MCE processors like
790 the 386 and 486, so nearly everyone can say Y here.
794 prompt "Intel MCE features"
795 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
797 Additional support for intel specific MCE features such as
802 prompt "AMD MCE features"
803 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
805 Additional support for AMD specific MCE features such as
806 the DRAM Error Threshold.
808 config X86_MCE_THRESHOLD
809 depends on X86_MCE_AMD || X86_MCE_INTEL
813 config X86_MCE_NONFATAL
814 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
815 depends on X86_32 && X86_MCE
817 Enabling this feature starts a timer that triggers every 5 seconds which
818 will look at the machine check registers to see if anything happened.
819 Non-fatal problems automatically get corrected (but still logged).
820 Disable this if you don't want to see these messages.
821 Seeing the messages this option prints out may be indicative of dying
822 or out-of-spec (ie, overclocked) hardware.
823 This option only does something on certain CPUs.
824 (AMD Athlon/Duron and Intel Pentium 4)
826 config X86_MCE_P4THERMAL
827 bool "check for P4 thermal throttling interrupt."
828 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
830 Enabling this feature will cause a message to be printed when the P4
831 enters thermal throttling.
834 bool "Enable VM86 support" if EMBEDDED
838 This option is required by programs like DOSEMU to run 16-bit legacy
839 code on X86 processors. It also may be needed by software like
840 XFree86 to initialize some video cards via BIOS. Disabling this
841 option saves about 6k.
844 tristate "Toshiba Laptop support"
847 This adds a driver to safely access the System Management Mode of
848 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
849 not work on models with a Phoenix BIOS. The System Management Mode
850 is used to set the BIOS and power saving options on Toshiba portables.
852 For information on utilities to make use of this driver see the
853 Toshiba Linux utilities web site at:
854 <http://www.buzzard.org.uk/toshiba/>.
856 Say Y if you intend to run this kernel on a Toshiba portable.
860 tristate "Dell laptop support"
862 This adds a driver to safely access the System Management Mode
863 of the CPU on the Dell Inspiron 8000. The System Management Mode
864 is used to read cpu temperature and cooling fan status and to
865 control the fans on the I8K portables.
867 This driver has been tested only on the Inspiron 8000 but it may
868 also work with other Dell laptops. You can force loading on other
869 models by passing the parameter `force=1' to the module. Use at
872 For information on utilities to make use of this driver see the
873 I8K Linux utilities web site at:
874 <http://people.debian.org/~dz/i8k/>
876 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
879 config X86_REBOOTFIXUPS
880 bool "Enable X86 board specific fixups for reboot"
883 This enables chipset and/or board specific fixups to be done
884 in order to get reboot to work correctly. This is only needed on
885 some combinations of hardware and BIOS. The symptom, for which
886 this config is intended, is when reboot ends with a stalled/hung
889 Currently, the only fixup is for the Geode machines using
890 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
892 Say Y if you want to enable the fixup. Currently, it's safe to
893 enable this option even if you don't need it.
897 tristate "/dev/cpu/microcode - microcode support"
900 If you say Y here, you will be able to update the microcode on
901 certain Intel and AMD processors. The Intel support is for the
902 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
903 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
904 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
905 You will obviously need the actual microcode binary data itself
906 which is not shipped with the Linux kernel.
908 This option selects the general module only, you need to select
909 at least one vendor specific module as well.
911 To compile this driver as a module, choose M here: the
912 module will be called microcode.
914 config MICROCODE_INTEL
915 bool "Intel microcode patch loading support"
920 This options enables microcode patch loading support for Intel
923 For latest news and information on obtaining all the required
924 Intel ingredients for this driver, check:
925 <http://www.urbanmyth.org/microcode/>.
928 bool "AMD microcode patch loading support"
932 If you select this option, microcode patch loading support for AMD
933 processors will be enabled.
935 config MICROCODE_OLD_INTERFACE
940 tristate "/dev/cpu/*/msr - Model-specific register support"
942 This device gives privileged processes access to the x86
943 Model-Specific Registers (MSRs). It is a character device with
944 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
945 MSR accesses are directed to a specific CPU on multi-processor
949 tristate "/dev/cpu/*/cpuid - CPU information support"
951 This device gives processes access to the x86 CPUID instruction to
952 be executed on a specific processor. It is a character device
953 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
957 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
959 If you select this option, this will provide various x86 CPUs
960 information through debugfs.
963 prompt "High Memory Support"
964 default HIGHMEM4G if !X86_NUMAQ
965 default HIGHMEM64G if X86_NUMAQ
970 depends on !X86_NUMAQ
972 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
973 However, the address space of 32-bit x86 processors is only 4
974 Gigabytes large. That means that, if you have a large amount of
975 physical memory, not all of it can be "permanently mapped" by the
976 kernel. The physical memory that's not permanently mapped is called
979 If you are compiling a kernel which will never run on a machine with
980 more than 1 Gigabyte total physical RAM, answer "off" here (default
981 choice and suitable for most users). This will result in a "3GB/1GB"
982 split: 3GB are mapped so that each process sees a 3GB virtual memory
983 space and the remaining part of the 4GB virtual memory space is used
984 by the kernel to permanently map as much physical memory as
987 If the machine has between 1 and 4 Gigabytes physical RAM, then
990 If more than 4 Gigabytes is used then answer "64GB" here. This
991 selection turns Intel PAE (Physical Address Extension) mode on.
992 PAE implements 3-level paging on IA32 processors. PAE is fully
993 supported by Linux, PAE mode is implemented on all recent Intel
994 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
995 then the kernel will not boot on CPUs that don't support PAE!
997 The actual amount of total physical memory will either be
998 auto detected or can be forced by using a kernel command line option
999 such as "mem=256M". (Try "man bootparam" or see the documentation of
1000 your boot loader (lilo or loadlin) about how to pass options to the
1001 kernel at boot time.)
1003 If unsure, say "off".
1007 depends on !X86_NUMAQ
1009 Select this if you have a 32-bit processor and between 1 and 4
1010 gigabytes of physical RAM.
1014 depends on !M386 && !M486
1017 Select this if you have a 32-bit processor and more than 4
1018 gigabytes of physical RAM.
1023 depends on EXPERIMENTAL
1024 prompt "Memory split" if EMBEDDED
1028 Select the desired split between kernel and user memory.
1030 If the address range available to the kernel is less than the
1031 physical memory installed, the remaining memory will be available
1032 as "high memory". Accessing high memory is a little more costly
1033 than low memory, as it needs to be mapped into the kernel first.
1034 Note that increasing the kernel address space limits the range
1035 available to user programs, making the address space there
1036 tighter. Selecting anything other than the default 3G/1G split
1037 will also likely make your kernel incompatible with binary-only
1040 If you are not absolutely sure what you are doing, leave this
1044 bool "3G/1G user/kernel split"
1045 config VMSPLIT_3G_OPT
1047 bool "3G/1G user/kernel split (for full 1G low memory)"
1049 bool "2G/2G user/kernel split"
1050 config VMSPLIT_2G_OPT
1052 bool "2G/2G user/kernel split (for full 2G low memory)"
1054 bool "1G/3G user/kernel split"
1059 default 0xB0000000 if VMSPLIT_3G_OPT
1060 default 0x80000000 if VMSPLIT_2G
1061 default 0x78000000 if VMSPLIT_2G_OPT
1062 default 0x40000000 if VMSPLIT_1G
1068 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1071 bool "PAE (Physical Address Extension) Support"
1072 depends on X86_32 && !HIGHMEM4G
1074 PAE is required for NX support, and furthermore enables
1075 larger swapspace support for non-overcommit purposes. It
1076 has the cost of more pagetable lookup overhead, and also
1077 consumes more pagetable space per process.
1079 config ARCH_PHYS_ADDR_T_64BIT
1080 def_bool X86_64 || X86_PAE
1082 config DIRECT_GBPAGES
1083 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1087 Allow the kernel linear mapping to use 1GB pages on CPUs that
1088 support it. This can improve the kernel's performance a tiny bit by
1089 reducing TLB pressure. If in doubt, say "Y".
1091 # Common NUMA Features
1093 bool "Numa Memory Allocation and Scheduler Support"
1095 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1096 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1098 Enable NUMA (Non Uniform Memory Access) support.
1100 The kernel will try to allocate memory used by a CPU on the
1101 local memory controller of the CPU and add some more
1102 NUMA awareness to the kernel.
1104 For 64-bit this is recommended if the system is Intel Core i7
1105 (or later), AMD Opteron, or EM64T NUMA.
1107 For 32-bit this is only needed on (rare) 32-bit-only platforms
1108 that support NUMA topologies, such as NUMAQ / Summit, or if you
1109 boot a 32-bit kernel on a 64-bit NUMA platform.
1111 Otherwise, you should say N.
1113 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1114 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1118 prompt "Old style AMD Opteron NUMA detection"
1119 depends on X86_64 && NUMA && PCI
1121 Enable K8 NUMA node topology detection. You should say Y here if
1122 you have a multi processor AMD K8 system. This uses an old
1123 method to read the NUMA configuration directly from the builtin
1124 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1125 instead, which also takes priority if both are compiled in.
1127 config X86_64_ACPI_NUMA
1129 prompt "ACPI NUMA detection"
1130 depends on X86_64 && NUMA && ACPI && PCI
1133 Enable ACPI SRAT based node topology detection.
1135 # Some NUMA nodes have memory ranges that span
1136 # other nodes. Even though a pfn is valid and
1137 # between a node's start and end pfns, it may not
1138 # reside on that node. See memmap_init_zone()
1140 config NODES_SPAN_OTHER_NODES
1142 depends on X86_64_ACPI_NUMA
1145 bool "NUMA emulation"
1146 depends on X86_64 && NUMA
1148 Enable NUMA emulation. A flat machine will be split
1149 into virtual nodes when booted with "numa=fake=N", where N is the
1150 number of nodes. This is only useful for debugging.
1153 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1155 default "9" if MAXSMP
1156 default "6" if X86_64
1157 default "4" if X86_NUMAQ
1159 depends on NEED_MULTIPLE_NODES
1161 Specify the maximum number of NUMA Nodes available on the target
1162 system. Increases memory reserved to accommodate various tables.
1164 config HAVE_ARCH_BOOTMEM
1166 depends on X86_32 && NUMA
1168 config ARCH_HAVE_MEMORY_PRESENT
1170 depends on X86_32 && DISCONTIGMEM
1172 config NEED_NODE_MEMMAP_SIZE
1174 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1176 config HAVE_ARCH_ALLOC_REMAP
1178 depends on X86_32 && NUMA
1180 config ARCH_FLATMEM_ENABLE
1182 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1184 config ARCH_DISCONTIGMEM_ENABLE
1186 depends on NUMA && X86_32
1188 config ARCH_DISCONTIGMEM_DEFAULT
1190 depends on NUMA && X86_32
1192 config ARCH_SPARSEMEM_DEFAULT
1196 config ARCH_SPARSEMEM_ENABLE
1198 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1199 select SPARSEMEM_STATIC if X86_32
1200 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1202 config ARCH_SELECT_MEMORY_MODEL
1204 depends on ARCH_SPARSEMEM_ENABLE
1206 config ARCH_MEMORY_PROBE
1208 depends on MEMORY_HOTPLUG
1213 bool "Allocate 3rd-level pagetables from highmem"
1214 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1216 The VM uses one page table entry for each page of physical memory.
1217 For systems with a lot of RAM, this can be wasteful of precious
1218 low memory. Setting this option will put user-space page table
1219 entries in high memory.
1221 config X86_CHECK_BIOS_CORRUPTION
1222 bool "Check for low memory corruption"
1224 Periodically check for memory corruption in low memory, which
1225 is suspected to be caused by BIOS. Even when enabled in the
1226 configuration, it is disabled at runtime. Enable it by
1227 setting "memory_corruption_check=1" on the kernel command
1228 line. By default it scans the low 64k of memory every 60
1229 seconds; see the memory_corruption_check_size and
1230 memory_corruption_check_period parameters in
1231 Documentation/kernel-parameters.txt to adjust this.
1233 When enabled with the default parameters, this option has
1234 almost no overhead, as it reserves a relatively small amount
1235 of memory and scans it infrequently. It both detects corruption
1236 and prevents it from affecting the running system.
1238 It is, however, intended as a diagnostic tool; if repeatable
1239 BIOS-originated corruption always affects the same memory,
1240 you can use memmap= to prevent the kernel from using that
1243 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1244 bool "Set the default setting of memory_corruption_check"
1245 depends on X86_CHECK_BIOS_CORRUPTION
1248 Set whether the default state of memory_corruption_check is
1251 config X86_RESERVE_LOW_64K
1252 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1255 Reserve the first 64K of physical RAM on BIOSes that are known
1256 to potentially corrupt that memory range. A numbers of BIOSes are
1257 known to utilize this area during suspend/resume, so it must not
1258 be used by the kernel.
1260 Set this to N if you are absolutely sure that you trust the BIOS
1261 to get all its memory reservations and usages right.
1263 If you have doubts about the BIOS (e.g. suspend/resume does not
1264 work or there's kernel crashes after certain hardware hotplug
1265 events) and it's not AMI or Phoenix, then you might want to enable
1266 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1267 corruption patterns.
1271 config MATH_EMULATION
1273 prompt "Math emulation" if X86_32
1275 Linux can emulate a math coprocessor (used for floating point
1276 operations) if you don't have one. 486DX and Pentium processors have
1277 a math coprocessor built in, 486SX and 386 do not, unless you added
1278 a 487DX or 387, respectively. (The messages during boot time can
1279 give you some hints here ["man dmesg"].) Everyone needs either a
1280 coprocessor or this emulation.
1282 If you don't have a math coprocessor, you need to say Y here; if you
1283 say Y here even though you have a coprocessor, the coprocessor will
1284 be used nevertheless. (This behavior can be changed with the kernel
1285 command line option "no387", which comes handy if your coprocessor
1286 is broken. Try "man bootparam" or see the documentation of your boot
1287 loader (lilo or loadlin) about how to pass options to the kernel at
1288 boot time.) This means that it is a good idea to say Y here if you
1289 intend to use this kernel on different machines.
1291 More information about the internals of the Linux math coprocessor
1292 emulation can be found in <file:arch/x86/math-emu/README>.
1294 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1295 kernel, it won't hurt.
1298 bool "MTRR (Memory Type Range Register) support"
1300 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1301 the Memory Type Range Registers (MTRRs) may be used to control
1302 processor access to memory ranges. This is most useful if you have
1303 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1304 allows bus write transfers to be combined into a larger transfer
1305 before bursting over the PCI/AGP bus. This can increase performance
1306 of image write operations 2.5 times or more. Saying Y here creates a
1307 /proc/mtrr file which may be used to manipulate your processor's
1308 MTRRs. Typically the X server should use this.
1310 This code has a reasonably generic interface so that similar
1311 control registers on other processors can be easily supported
1314 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1315 Registers (ARRs) which provide a similar functionality to MTRRs. For
1316 these, the ARRs are used to emulate the MTRRs.
1317 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1318 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1319 write-combining. All of these processors are supported by this code
1320 and it makes sense to say Y here if you have one of them.
1322 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1323 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1324 can lead to all sorts of problems, so it's good to say Y here.
1326 You can safely say Y even if your machine doesn't have MTRRs, you'll
1327 just add about 9 KB to your kernel.
1329 See <file:Documentation/x86/mtrr.txt> for more information.
1331 config MTRR_SANITIZER
1333 prompt "MTRR cleanup support"
1336 Convert MTRR layout from continuous to discrete, so X drivers can
1337 add writeback entries.
1339 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1340 The largest mtrr entry size for a continuous block can be set with
1345 config MTRR_SANITIZER_ENABLE_DEFAULT
1346 int "MTRR cleanup enable value (0-1)"
1349 depends on MTRR_SANITIZER
1351 Enable mtrr cleanup default value
1353 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1354 int "MTRR cleanup spare reg num (0-7)"
1357 depends on MTRR_SANITIZER
1359 mtrr cleanup spare entries default, it can be changed via
1360 mtrr_spare_reg_nr=N on the kernel command line.
1364 prompt "x86 PAT support"
1367 Use PAT attributes to setup page level cache control.
1369 PATs are the modern equivalents of MTRRs and are much more
1370 flexible than MTRRs.
1372 Say N here if you see bootup problems (boot crash, boot hang,
1373 spontaneous reboots) or a non-working video driver.
1378 bool "EFI runtime service support"
1381 This enables the kernel to use EFI runtime services that are
1382 available (such as the EFI variable services).
1384 This option is only useful on systems that have EFI firmware.
1385 In addition, you should use the latest ELILO loader available
1386 at <http://elilo.sourceforge.net> in order to take advantage
1387 of EFI runtime services. However, even with this option, the
1388 resultant kernel should continue to boot on existing non-EFI
1393 prompt "Enable seccomp to safely compute untrusted bytecode"
1395 This kernel feature is useful for number crunching applications
1396 that may need to compute untrusted bytecode during their
1397 execution. By using pipes or other transports made available to
1398 the process as file descriptors supporting the read/write
1399 syscalls, it's possible to isolate those applications in
1400 their own address space using seccomp. Once seccomp is
1401 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1402 and the task is only allowed to execute a few safe syscalls
1403 defined by each seccomp mode.
1405 If unsure, say Y. Only embedded should say N here.
1407 config CC_STACKPROTECTOR_ALL
1410 config CC_STACKPROTECTOR
1411 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1412 select CC_STACKPROTECTOR_ALL
1414 This option turns on the -fstack-protector GCC feature. This
1415 feature puts, at the beginning of functions, a canary value on
1416 the stack just before the return address, and validates
1417 the value just before actually returning. Stack based buffer
1418 overflows (that need to overwrite this return address) now also
1419 overwrite the canary, which gets detected and the attack is then
1420 neutralized via a kernel panic.
1422 This feature requires gcc version 4.2 or above, or a distribution
1423 gcc with the feature backported. Older versions are automatically
1424 detected and for those versions, this configuration option is
1425 ignored. (and a warning is printed during bootup)
1427 source kernel/Kconfig.hz
1430 bool "kexec system call"
1432 kexec is a system call that implements the ability to shutdown your
1433 current kernel, and to start another kernel. It is like a reboot
1434 but it is independent of the system firmware. And like a reboot
1435 you can start any kernel with it, not just Linux.
1437 The name comes from the similarity to the exec system call.
1439 It is an ongoing process to be certain the hardware in a machine
1440 is properly shutdown, so do not be surprised if this code does not
1441 initially work for you. It may help to enable device hotplugging
1442 support. As of this writing the exact hardware interface is
1443 strongly in flux, so no good recommendation can be made.
1446 bool "kernel crash dumps"
1447 depends on X86_64 || (X86_32 && HIGHMEM)
1449 Generate crash dump after being started by kexec.
1450 This should be normally only set in special crash dump kernels
1451 which are loaded in the main kernel with kexec-tools into
1452 a specially reserved region and then later executed after
1453 a crash by kdump/kexec. The crash dump kernel must be compiled
1454 to a memory address not used by the main kernel or BIOS using
1455 PHYSICAL_START, or it must be built as a relocatable image
1456 (CONFIG_RELOCATABLE=y).
1457 For more details see Documentation/kdump/kdump.txt
1460 bool "kexec jump (EXPERIMENTAL)"
1461 depends on EXPERIMENTAL
1462 depends on KEXEC && HIBERNATION
1464 Jump between original kernel and kexeced kernel and invoke
1465 code in physical address mode via KEXEC
1467 config PHYSICAL_START
1468 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1471 This gives the physical address where the kernel is loaded.
1473 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1474 bzImage will decompress itself to above physical address and
1475 run from there. Otherwise, bzImage will run from the address where
1476 it has been loaded by the boot loader and will ignore above physical
1479 In normal kdump cases one does not have to set/change this option
1480 as now bzImage can be compiled as a completely relocatable image
1481 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1482 address. This option is mainly useful for the folks who don't want
1483 to use a bzImage for capturing the crash dump and want to use a
1484 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1485 to be specifically compiled to run from a specific memory area
1486 (normally a reserved region) and this option comes handy.
1488 So if you are using bzImage for capturing the crash dump,
1489 leave the value here unchanged to 0x1000000 and set
1490 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1491 for capturing the crash dump change this value to start of
1492 the reserved region. In other words, it can be set based on
1493 the "X" value as specified in the "crashkernel=YM@XM"
1494 command line boot parameter passed to the panic-ed
1495 kernel. Please take a look at Documentation/kdump/kdump.txt
1496 for more details about crash dumps.
1498 Usage of bzImage for capturing the crash dump is recommended as
1499 one does not have to build two kernels. Same kernel can be used
1500 as production kernel and capture kernel. Above option should have
1501 gone away after relocatable bzImage support is introduced. But it
1502 is present because there are users out there who continue to use
1503 vmlinux for dump capture. This option should go away down the
1506 Don't change this unless you know what you are doing.
1509 bool "Build a relocatable kernel"
1512 This builds a kernel image that retains relocation information
1513 so it can be loaded someplace besides the default 1MB.
1514 The relocations tend to make the kernel binary about 10% larger,
1515 but are discarded at runtime.
1517 One use is for the kexec on panic case where the recovery kernel
1518 must live at a different physical address than the primary
1521 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1522 it has been loaded at and the compile time physical address
1523 (CONFIG_PHYSICAL_START) is ignored.
1525 # Relocation on x86-32 needs some additional build support
1526 config X86_NEED_RELOCS
1528 depends on X86_32 && RELOCATABLE
1530 config PHYSICAL_ALIGN
1532 prompt "Alignment value to which kernel should be aligned" if X86_32
1534 range 0x2000 0x1000000
1536 This value puts the alignment restrictions on physical address
1537 where kernel is loaded and run from. Kernel is compiled for an
1538 address which meets above alignment restriction.
1540 If bootloader loads the kernel at a non-aligned address and
1541 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1542 address aligned to above value and run from there.
1544 If bootloader loads the kernel at a non-aligned address and
1545 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1546 load address and decompress itself to the address it has been
1547 compiled for and run from there. The address for which kernel is
1548 compiled already meets above alignment restrictions. Hence the
1549 end result is that kernel runs from a physical address meeting
1550 above alignment restrictions.
1552 Don't change this unless you know what you are doing.
1555 bool "Support for hot-pluggable CPUs"
1556 depends on SMP && HOTPLUG
1558 Say Y here to allow turning CPUs off and on. CPUs can be
1559 controlled through /sys/devices/system/cpu.
1560 ( Note: power management support will enable this option
1561 automatically on SMP systems. )
1562 Say N if you want to disable CPU hotplug.
1566 prompt "Compat VDSO support"
1567 depends on X86_32 || IA32_EMULATION
1569 Map the 32-bit VDSO to the predictable old-style address too.
1571 Say N here if you are running a sufficiently recent glibc
1572 version (2.3.3 or later), to remove the high-mapped
1573 VDSO mapping and to exclusively use the randomized VDSO.
1578 bool "Built-in kernel command line"
1581 Allow for specifying boot arguments to the kernel at
1582 build time. On some systems (e.g. embedded ones), it is
1583 necessary or convenient to provide some or all of the
1584 kernel boot arguments with the kernel itself (that is,
1585 to not rely on the boot loader to provide them.)
1587 To compile command line arguments into the kernel,
1588 set this option to 'Y', then fill in the
1589 the boot arguments in CONFIG_CMDLINE.
1591 Systems with fully functional boot loaders (i.e. non-embedded)
1592 should leave this option set to 'N'.
1595 string "Built-in kernel command string"
1596 depends on CMDLINE_BOOL
1599 Enter arguments here that should be compiled into the kernel
1600 image and used at boot time. If the boot loader provides a
1601 command line at boot time, it is appended to this string to
1602 form the full kernel command line, when the system boots.
1604 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1605 change this behavior.
1607 In most cases, the command line (whether built-in or provided
1608 by the boot loader) should specify the device for the root
1611 config CMDLINE_OVERRIDE
1612 bool "Built-in command line overrides boot loader arguments"
1614 depends on CMDLINE_BOOL
1616 Set this option to 'Y' to have the kernel ignore the boot loader
1617 command line, and use ONLY the built-in command line.
1619 This is used to work around broken boot loaders. This should
1620 be set to 'N' under normal conditions.
1624 config ARCH_ENABLE_MEMORY_HOTPLUG
1626 depends on X86_64 || (X86_32 && HIGHMEM)
1628 config ARCH_ENABLE_MEMORY_HOTREMOVE
1630 depends on MEMORY_HOTPLUG
1632 config HAVE_ARCH_EARLY_PFN_TO_NID
1636 menu "Power management and ACPI options"
1638 config ARCH_HIBERNATION_HEADER
1640 depends on X86_64 && HIBERNATION
1642 source "kernel/power/Kconfig"
1644 source "drivers/acpi/Kconfig"
1649 depends on APM || APM_MODULE
1652 tristate "APM (Advanced Power Management) BIOS support"
1653 depends on X86_32 && PM_SLEEP
1655 APM is a BIOS specification for saving power using several different
1656 techniques. This is mostly useful for battery powered laptops with
1657 APM compliant BIOSes. If you say Y here, the system time will be
1658 reset after a RESUME operation, the /proc/apm device will provide
1659 battery status information, and user-space programs will receive
1660 notification of APM "events" (e.g. battery status change).
1662 If you select "Y" here, you can disable actual use of the APM
1663 BIOS by passing the "apm=off" option to the kernel at boot time.
1665 Note that the APM support is almost completely disabled for
1666 machines with more than one CPU.
1668 In order to use APM, you will need supporting software. For location
1669 and more information, read <file:Documentation/power/pm.txt> and the
1670 Battery Powered Linux mini-HOWTO, available from
1671 <http://www.tldp.org/docs.html#howto>.
1673 This driver does not spin down disk drives (see the hdparm(8)
1674 manpage ("man 8 hdparm") for that), and it doesn't turn off
1675 VESA-compliant "green" monitors.
1677 This driver does not support the TI 4000M TravelMate and the ACER
1678 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1679 desktop machines also don't have compliant BIOSes, and this driver
1680 may cause those machines to panic during the boot phase.
1682 Generally, if you don't have a battery in your machine, there isn't
1683 much point in using this driver and you should say N. If you get
1684 random kernel OOPSes or reboots that don't seem to be related to
1685 anything, try disabling/enabling this option (or disabling/enabling
1688 Some other things you should try when experiencing seemingly random,
1691 1) make sure that you have enough swap space and that it is
1693 2) pass the "no-hlt" option to the kernel
1694 3) switch on floating point emulation in the kernel and pass
1695 the "no387" option to the kernel
1696 4) pass the "floppy=nodma" option to the kernel
1697 5) pass the "mem=4M" option to the kernel (thereby disabling
1698 all but the first 4 MB of RAM)
1699 6) make sure that the CPU is not over clocked.
1700 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1701 8) disable the cache from your BIOS settings
1702 9) install a fan for the video card or exchange video RAM
1703 10) install a better fan for the CPU
1704 11) exchange RAM chips
1705 12) exchange the motherboard.
1707 To compile this driver as a module, choose M here: the
1708 module will be called apm.
1712 config APM_IGNORE_USER_SUSPEND
1713 bool "Ignore USER SUSPEND"
1715 This option will ignore USER SUSPEND requests. On machines with a
1716 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1717 series notebooks, it is necessary to say Y because of a BIOS bug.
1719 config APM_DO_ENABLE
1720 bool "Enable PM at boot time"
1722 Enable APM features at boot time. From page 36 of the APM BIOS
1723 specification: "When disabled, the APM BIOS does not automatically
1724 power manage devices, enter the Standby State, enter the Suspend
1725 State, or take power saving steps in response to CPU Idle calls."
1726 This driver will make CPU Idle calls when Linux is idle (unless this
1727 feature is turned off -- see "Do CPU IDLE calls", below). This
1728 should always save battery power, but more complicated APM features
1729 will be dependent on your BIOS implementation. You may need to turn
1730 this option off if your computer hangs at boot time when using APM
1731 support, or if it beeps continuously instead of suspending. Turn
1732 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1733 T400CDT. This is off by default since most machines do fine without
1737 bool "Make CPU Idle calls when idle"
1739 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1740 On some machines, this can activate improved power savings, such as
1741 a slowed CPU clock rate, when the machine is idle. These idle calls
1742 are made after the idle loop has run for some length of time (e.g.,
1743 333 mS). On some machines, this will cause a hang at boot time or
1744 whenever the CPU becomes idle. (On machines with more than one CPU,
1745 this option does nothing.)
1747 config APM_DISPLAY_BLANK
1748 bool "Enable console blanking using APM"
1750 Enable console blanking using the APM. Some laptops can use this to
1751 turn off the LCD backlight when the screen blanker of the Linux
1752 virtual console blanks the screen. Note that this is only used by
1753 the virtual console screen blanker, and won't turn off the backlight
1754 when using the X Window system. This also doesn't have anything to
1755 do with your VESA-compliant power-saving monitor. Further, this
1756 option doesn't work for all laptops -- it might not turn off your
1757 backlight at all, or it might print a lot of errors to the console,
1758 especially if you are using gpm.
1760 config APM_ALLOW_INTS
1761 bool "Allow interrupts during APM BIOS calls"
1763 Normally we disable external interrupts while we are making calls to
1764 the APM BIOS as a measure to lessen the effects of a badly behaving
1765 BIOS implementation. The BIOS should reenable interrupts if it
1766 needs to. Unfortunately, some BIOSes do not -- especially those in
1767 many of the newer IBM Thinkpads. If you experience hangs when you
1768 suspend, try setting this to Y. Otherwise, say N.
1772 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1774 source "drivers/cpuidle/Kconfig"
1776 source "drivers/idle/Kconfig"
1781 menu "Bus options (PCI etc.)"
1786 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1788 Find out whether you have a PCI motherboard. PCI is the name of a
1789 bus system, i.e. the way the CPU talks to the other stuff inside
1790 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1791 VESA. If you have PCI, say Y, otherwise N.
1794 prompt "PCI access mode"
1795 depends on X86_32 && PCI
1798 On PCI systems, the BIOS can be used to detect the PCI devices and
1799 determine their configuration. However, some old PCI motherboards
1800 have BIOS bugs and may crash if this is done. Also, some embedded
1801 PCI-based systems don't have any BIOS at all. Linux can also try to
1802 detect the PCI hardware directly without using the BIOS.
1804 With this option, you can specify how Linux should detect the
1805 PCI devices. If you choose "BIOS", the BIOS will be used,
1806 if you choose "Direct", the BIOS won't be used, and if you
1807 choose "MMConfig", then PCI Express MMCONFIG will be used.
1808 If you choose "Any", the kernel will try MMCONFIG, then the
1809 direct access method and falls back to the BIOS if that doesn't
1810 work. If unsure, go with the default, which is "Any".
1815 config PCI_GOMMCONFIG
1832 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1834 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1837 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1841 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1845 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1852 bool "Support mmconfig PCI config space access"
1853 depends on X86_64 && PCI && ACPI
1856 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1857 depends on PCI_MSI && ACPI && EXPERIMENTAL
1859 DMA remapping (DMAR) devices support enables independent address
1860 translations for Direct Memory Access (DMA) from devices.
1861 These DMA remapping devices are reported via ACPI tables
1862 and include PCI device scope covered by these DMA
1865 config DMAR_DEFAULT_ON
1867 prompt "Enable DMA Remapping Devices by default"
1870 Selecting this option will enable a DMAR device at boot time if
1871 one is found. If this option is not selected, DMAR support can
1872 be enabled by passing intel_iommu=on to the kernel. It is
1873 recommended you say N here while the DMAR code remains
1878 prompt "Support for Graphics workaround"
1881 Current Graphics drivers tend to use physical address
1882 for DMA and avoid using DMA APIs. Setting this config
1883 option permits the IOMMU driver to set a unity map for
1884 all the OS-visible memory. Hence the driver can continue
1885 to use physical addresses for DMA.
1887 config DMAR_FLOPPY_WA
1891 Floppy disk drivers are know to bypass DMA API calls
1892 thereby failing to work when IOMMU is enabled. This
1893 workaround will setup a 1:1 mapping for the first
1894 16M to make floppy (an ISA device) work.
1897 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1898 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1900 Supports Interrupt remapping for IO-APIC and MSI devices.
1901 To use x2apic mode in the CPU's which support x2APIC enhancements or
1902 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1904 source "drivers/pci/pcie/Kconfig"
1906 source "drivers/pci/Kconfig"
1908 # x86_64 have no ISA slots, but do have ISA-style DMA.
1917 Find out whether you have ISA slots on your motherboard. ISA is the
1918 name of a bus system, i.e. the way the CPU talks to the other stuff
1919 inside your box. Other bus systems are PCI, EISA, MicroChannel
1920 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1921 newer boards don't support it. If you have ISA, say Y, otherwise N.
1927 The Extended Industry Standard Architecture (EISA) bus was
1928 developed as an open alternative to the IBM MicroChannel bus.
1930 The EISA bus provided some of the features of the IBM MicroChannel
1931 bus while maintaining backward compatibility with cards made for
1932 the older ISA bus. The EISA bus saw limited use between 1988 and
1933 1995 when it was made obsolete by the PCI bus.
1935 Say Y here if you are building a kernel for an EISA-based machine.
1939 source "drivers/eisa/Kconfig"
1944 MicroChannel Architecture is found in some IBM PS/2 machines and
1945 laptops. It is a bus system similar to PCI or ISA. See
1946 <file:Documentation/mca.txt> (and especially the web page given
1947 there) before attempting to build an MCA bus kernel.
1949 source "drivers/mca/Kconfig"
1952 tristate "NatSemi SCx200 support"
1954 This provides basic support for National Semiconductor's
1955 (now AMD's) Geode processors. The driver probes for the
1956 PCI-IDs of several on-chip devices, so its a good dependency
1957 for other scx200_* drivers.
1959 If compiled as a module, the driver is named scx200.
1961 config SCx200HR_TIMER
1962 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1963 depends on SCx200 && GENERIC_TIME
1966 This driver provides a clocksource built upon the on-chip
1967 27MHz high-resolution timer. Its also a workaround for
1968 NSC Geode SC-1100's buggy TSC, which loses time when the
1969 processor goes idle (as is done by the scheduler). The
1970 other workaround is idle=poll boot option.
1972 config GEODE_MFGPT_TIMER
1974 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1975 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1977 This driver provides a clock event source based on the MFGPT
1978 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1979 MFGPTs have a better resolution and max interval than the
1980 generic PIT, and are suitable for use as high-res timers.
1983 bool "One Laptop Per Child support"
1986 Add support for detecting the unique features of the OLPC
1993 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1995 source "drivers/pcmcia/Kconfig"
1997 source "drivers/pci/hotplug/Kconfig"
2002 menu "Executable file formats / Emulations"
2004 source "fs/Kconfig.binfmt"
2006 config IA32_EMULATION
2007 bool "IA32 Emulation"
2009 select COMPAT_BINFMT_ELF
2011 Include code to run 32-bit programs under a 64-bit kernel. You should
2012 likely turn this on, unless you're 100% sure that you don't have any
2013 32-bit programs left.
2016 tristate "IA32 a.out support"
2017 depends on IA32_EMULATION
2019 Support old a.out binaries in the 32bit emulation.
2023 depends on IA32_EMULATION
2025 config COMPAT_FOR_U64_ALIGNMENT
2029 config SYSVIPC_COMPAT
2031 depends on COMPAT && SYSVIPC
2036 config HAVE_ATOMIC_IOMAP
2040 source "net/Kconfig"
2042 source "drivers/Kconfig"
2044 source "drivers/firmware/Kconfig"
2048 source "arch/x86/Kconfig.debug"
2050 source "security/Kconfig"
2052 source "crypto/Kconfig"
2054 source "arch/x86/kvm/Kconfig"
2056 source "lib/Kconfig"
projects / linux-2.6 / blob