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
745 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
747 config X86_VISWS_APIC
749 depends on X86_32 && X86_VISWS
751 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
752 bool "Reroute for broken boot IRQs"
754 depends on X86_IO_APIC
756 This option enables a workaround that fixes a source of
757 spurious interrupts. This is recommended when threaded
758 interrupt handling is used on systems where the generation of
759 superfluous "boot interrupts" cannot be disabled.
761 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
762 entry in the chipset's IO-APIC is masked (as, e.g. the RT
763 kernel does during interrupt handling). On chipsets where this
764 boot IRQ generation cannot be disabled, this workaround keeps
765 the original IRQ line masked so that only the equivalent "boot
766 IRQ" is delivered to the CPUs. The workaround also tells the
767 kernel to set up the IRQ handler on the boot IRQ line. In this
768 way only one interrupt is delivered to the kernel. Otherwise
769 the spurious second interrupt may cause the kernel to bring
770 down (vital) interrupt lines.
772 Only affects "broken" chipsets. Interrupt sharing may be
773 increased on these systems.
776 bool "Machine Check Exception"
778 Machine Check Exception support allows the processor to notify the
779 kernel if it detects a problem (e.g. overheating, component failure).
780 The action the kernel takes depends on the severity of the problem,
781 ranging from a warning message on the console, to halting the machine.
782 Your processor must be a Pentium or newer to support this - check the
783 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
784 have a design flaw which leads to false MCE events - hence MCE is
785 disabled on all P5 processors, unless explicitly enabled with "mce"
786 as a boot argument. Similarly, if MCE is built in and creates a
787 problem on some new non-standard machine, you can boot with "nomce"
788 to disable it. MCE support simply ignores non-MCE processors like
789 the 386 and 486, so nearly everyone can say Y here.
793 prompt "Intel MCE features"
794 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
796 Additional support for intel specific MCE features such as
801 prompt "AMD MCE features"
802 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
804 Additional support for AMD specific MCE features such as
805 the DRAM Error Threshold.
807 config X86_MCE_THRESHOLD
808 depends on X86_MCE_AMD || X86_MCE_INTEL
812 config X86_MCE_NONFATAL
813 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
814 depends on X86_32 && X86_MCE
816 Enabling this feature starts a timer that triggers every 5 seconds which
817 will look at the machine check registers to see if anything happened.
818 Non-fatal problems automatically get corrected (but still logged).
819 Disable this if you don't want to see these messages.
820 Seeing the messages this option prints out may be indicative of dying
821 or out-of-spec (ie, overclocked) hardware.
822 This option only does something on certain CPUs.
823 (AMD Athlon/Duron and Intel Pentium 4)
825 config X86_MCE_P4THERMAL
826 bool "check for P4 thermal throttling interrupt."
827 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
829 Enabling this feature will cause a message to be printed when the P4
830 enters thermal throttling.
833 bool "Enable VM86 support" if EMBEDDED
837 This option is required by programs like DOSEMU to run 16-bit legacy
838 code on X86 processors. It also may be needed by software like
839 XFree86 to initialize some video cards via BIOS. Disabling this
840 option saves about 6k.
843 tristate "Toshiba Laptop support"
846 This adds a driver to safely access the System Management Mode of
847 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
848 not work on models with a Phoenix BIOS. The System Management Mode
849 is used to set the BIOS and power saving options on Toshiba portables.
851 For information on utilities to make use of this driver see the
852 Toshiba Linux utilities web site at:
853 <http://www.buzzard.org.uk/toshiba/>.
855 Say Y if you intend to run this kernel on a Toshiba portable.
859 tristate "Dell laptop support"
861 This adds a driver to safely access the System Management Mode
862 of the CPU on the Dell Inspiron 8000. The System Management Mode
863 is used to read cpu temperature and cooling fan status and to
864 control the fans on the I8K portables.
866 This driver has been tested only on the Inspiron 8000 but it may
867 also work with other Dell laptops. You can force loading on other
868 models by passing the parameter `force=1' to the module. Use at
871 For information on utilities to make use of this driver see the
872 I8K Linux utilities web site at:
873 <http://people.debian.org/~dz/i8k/>
875 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
878 config X86_REBOOTFIXUPS
879 bool "Enable X86 board specific fixups for reboot"
882 This enables chipset and/or board specific fixups to be done
883 in order to get reboot to work correctly. This is only needed on
884 some combinations of hardware and BIOS. The symptom, for which
885 this config is intended, is when reboot ends with a stalled/hung
888 Currently, the only fixup is for the Geode machines using
889 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
891 Say Y if you want to enable the fixup. Currently, it's safe to
892 enable this option even if you don't need it.
896 tristate "/dev/cpu/microcode - microcode support"
899 If you say Y here, you will be able to update the microcode on
900 certain Intel and AMD processors. The Intel support is for the
901 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
902 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
903 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
904 You will obviously need the actual microcode binary data itself
905 which is not shipped with the Linux kernel.
907 This option selects the general module only, you need to select
908 at least one vendor specific module as well.
910 To compile this driver as a module, choose M here: the
911 module will be called microcode.
913 config MICROCODE_INTEL
914 bool "Intel microcode patch loading support"
919 This options enables microcode patch loading support for Intel
922 For latest news and information on obtaining all the required
923 Intel ingredients for this driver, check:
924 <http://www.urbanmyth.org/microcode/>.
927 bool "AMD microcode patch loading support"
931 If you select this option, microcode patch loading support for AMD
932 processors will be enabled.
934 config MICROCODE_OLD_INTERFACE
939 tristate "/dev/cpu/*/msr - Model-specific register support"
941 This device gives privileged processes access to the x86
942 Model-Specific Registers (MSRs). It is a character device with
943 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
944 MSR accesses are directed to a specific CPU on multi-processor
948 tristate "/dev/cpu/*/cpuid - CPU information support"
950 This device gives processes access to the x86 CPUID instruction to
951 be executed on a specific processor. It is a character device
952 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
956 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
958 If you select this option, this will provide various x86 CPUs
959 information through debugfs.
962 prompt "High Memory Support"
963 default HIGHMEM4G if !X86_NUMAQ
964 default HIGHMEM64G if X86_NUMAQ
969 depends on !X86_NUMAQ
971 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
972 However, the address space of 32-bit x86 processors is only 4
973 Gigabytes large. That means that, if you have a large amount of
974 physical memory, not all of it can be "permanently mapped" by the
975 kernel. The physical memory that's not permanently mapped is called
978 If you are compiling a kernel which will never run on a machine with
979 more than 1 Gigabyte total physical RAM, answer "off" here (default
980 choice and suitable for most users). This will result in a "3GB/1GB"
981 split: 3GB are mapped so that each process sees a 3GB virtual memory
982 space and the remaining part of the 4GB virtual memory space is used
983 by the kernel to permanently map as much physical memory as
986 If the machine has between 1 and 4 Gigabytes physical RAM, then
989 If more than 4 Gigabytes is used then answer "64GB" here. This
990 selection turns Intel PAE (Physical Address Extension) mode on.
991 PAE implements 3-level paging on IA32 processors. PAE is fully
992 supported by Linux, PAE mode is implemented on all recent Intel
993 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
994 then the kernel will not boot on CPUs that don't support PAE!
996 The actual amount of total physical memory will either be
997 auto detected or can be forced by using a kernel command line option
998 such as "mem=256M". (Try "man bootparam" or see the documentation of
999 your boot loader (lilo or loadlin) about how to pass options to the
1000 kernel at boot time.)
1002 If unsure, say "off".
1006 depends on !X86_NUMAQ
1008 Select this if you have a 32-bit processor and between 1 and 4
1009 gigabytes of physical RAM.
1013 depends on !M386 && !M486
1016 Select this if you have a 32-bit processor and more than 4
1017 gigabytes of physical RAM.
1022 depends on EXPERIMENTAL
1023 prompt "Memory split" if EMBEDDED
1027 Select the desired split between kernel and user memory.
1029 If the address range available to the kernel is less than the
1030 physical memory installed, the remaining memory will be available
1031 as "high memory". Accessing high memory is a little more costly
1032 than low memory, as it needs to be mapped into the kernel first.
1033 Note that increasing the kernel address space limits the range
1034 available to user programs, making the address space there
1035 tighter. Selecting anything other than the default 3G/1G split
1036 will also likely make your kernel incompatible with binary-only
1039 If you are not absolutely sure what you are doing, leave this
1043 bool "3G/1G user/kernel split"
1044 config VMSPLIT_3G_OPT
1046 bool "3G/1G user/kernel split (for full 1G low memory)"
1048 bool "2G/2G user/kernel split"
1049 config VMSPLIT_2G_OPT
1051 bool "2G/2G user/kernel split (for full 2G low memory)"
1053 bool "1G/3G user/kernel split"
1058 default 0xB0000000 if VMSPLIT_3G_OPT
1059 default 0x80000000 if VMSPLIT_2G
1060 default 0x78000000 if VMSPLIT_2G_OPT
1061 default 0x40000000 if VMSPLIT_1G
1067 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1070 bool "PAE (Physical Address Extension) Support"
1071 depends on X86_32 && !HIGHMEM4G
1073 PAE is required for NX support, and furthermore enables
1074 larger swapspace support for non-overcommit purposes. It
1075 has the cost of more pagetable lookup overhead, and also
1076 consumes more pagetable space per process.
1078 config ARCH_PHYS_ADDR_T_64BIT
1079 def_bool X86_64 || X86_PAE
1081 config DIRECT_GBPAGES
1082 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1086 Allow the kernel linear mapping to use 1GB pages on CPUs that
1087 support it. This can improve the kernel's performance a tiny bit by
1088 reducing TLB pressure. If in doubt, say "Y".
1090 # Common NUMA Features
1092 bool "Numa Memory Allocation and Scheduler Support"
1094 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1095 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1097 Enable NUMA (Non Uniform Memory Access) support.
1099 The kernel will try to allocate memory used by a CPU on the
1100 local memory controller of the CPU and add some more
1101 NUMA awareness to the kernel.
1103 For 64-bit this is recommended if the system is Intel Core i7
1104 (or later), AMD Opteron, or EM64T NUMA.
1106 For 32-bit this is only needed on (rare) 32-bit-only platforms
1107 that support NUMA topologies, such as NUMAQ / Summit, or if you
1108 boot a 32-bit kernel on a 64-bit NUMA platform.
1110 Otherwise, you should say N.
1112 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1113 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1117 prompt "Old style AMD Opteron NUMA detection"
1118 depends on X86_64 && NUMA && PCI
1120 Enable K8 NUMA node topology detection. You should say Y here if
1121 you have a multi processor AMD K8 system. This uses an old
1122 method to read the NUMA configuration directly from the builtin
1123 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1124 instead, which also takes priority if both are compiled in.
1126 config X86_64_ACPI_NUMA
1128 prompt "ACPI NUMA detection"
1129 depends on X86_64 && NUMA && ACPI && PCI
1132 Enable ACPI SRAT based node topology detection.
1134 # Some NUMA nodes have memory ranges that span
1135 # other nodes. Even though a pfn is valid and
1136 # between a node's start and end pfns, it may not
1137 # reside on that node. See memmap_init_zone()
1139 config NODES_SPAN_OTHER_NODES
1141 depends on X86_64_ACPI_NUMA
1144 bool "NUMA emulation"
1145 depends on X86_64 && NUMA
1147 Enable NUMA emulation. A flat machine will be split
1148 into virtual nodes when booted with "numa=fake=N", where N is the
1149 number of nodes. This is only useful for debugging.
1152 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1154 default "9" if MAXSMP
1155 default "6" if X86_64
1156 default "4" if X86_NUMAQ
1158 depends on NEED_MULTIPLE_NODES
1160 Specify the maximum number of NUMA Nodes available on the target
1161 system. Increases memory reserved to accommodate various tables.
1163 config HAVE_ARCH_BOOTMEM
1165 depends on X86_32 && NUMA
1167 config ARCH_HAVE_MEMORY_PRESENT
1169 depends on X86_32 && DISCONTIGMEM
1171 config NEED_NODE_MEMMAP_SIZE
1173 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1175 config HAVE_ARCH_ALLOC_REMAP
1177 depends on X86_32 && NUMA
1179 config ARCH_FLATMEM_ENABLE
1181 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1183 config ARCH_DISCONTIGMEM_ENABLE
1185 depends on NUMA && X86_32
1187 config ARCH_DISCONTIGMEM_DEFAULT
1189 depends on NUMA && X86_32
1191 config ARCH_SPARSEMEM_DEFAULT
1195 config ARCH_SPARSEMEM_ENABLE
1197 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1198 select SPARSEMEM_STATIC if X86_32
1199 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1201 config ARCH_SELECT_MEMORY_MODEL
1203 depends on ARCH_SPARSEMEM_ENABLE
1205 config ARCH_MEMORY_PROBE
1207 depends on MEMORY_HOTPLUG
1212 bool "Allocate 3rd-level pagetables from highmem"
1213 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1215 The VM uses one page table entry for each page of physical memory.
1216 For systems with a lot of RAM, this can be wasteful of precious
1217 low memory. Setting this option will put user-space page table
1218 entries in high memory.
1220 config X86_CHECK_BIOS_CORRUPTION
1221 bool "Check for low memory corruption"
1223 Periodically check for memory corruption in low memory, which
1224 is suspected to be caused by BIOS. Even when enabled in the
1225 configuration, it is disabled at runtime. Enable it by
1226 setting "memory_corruption_check=1" on the kernel command
1227 line. By default it scans the low 64k of memory every 60
1228 seconds; see the memory_corruption_check_size and
1229 memory_corruption_check_period parameters in
1230 Documentation/kernel-parameters.txt to adjust this.
1232 When enabled with the default parameters, this option has
1233 almost no overhead, as it reserves a relatively small amount
1234 of memory and scans it infrequently. It both detects corruption
1235 and prevents it from affecting the running system.
1237 It is, however, intended as a diagnostic tool; if repeatable
1238 BIOS-originated corruption always affects the same memory,
1239 you can use memmap= to prevent the kernel from using that
1242 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1243 bool "Set the default setting of memory_corruption_check"
1244 depends on X86_CHECK_BIOS_CORRUPTION
1247 Set whether the default state of memory_corruption_check is
1250 config X86_RESERVE_LOW_64K
1251 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1254 Reserve the first 64K of physical RAM on BIOSes that are known
1255 to potentially corrupt that memory range. A numbers of BIOSes are
1256 known to utilize this area during suspend/resume, so it must not
1257 be used by the kernel.
1259 Set this to N if you are absolutely sure that you trust the BIOS
1260 to get all its memory reservations and usages right.
1262 If you have doubts about the BIOS (e.g. suspend/resume does not
1263 work or there's kernel crashes after certain hardware hotplug
1264 events) and it's not AMI or Phoenix, then you might want to enable
1265 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1266 corruption patterns.
1270 config MATH_EMULATION
1272 prompt "Math emulation" if X86_32
1274 Linux can emulate a math coprocessor (used for floating point
1275 operations) if you don't have one. 486DX and Pentium processors have
1276 a math coprocessor built in, 486SX and 386 do not, unless you added
1277 a 487DX or 387, respectively. (The messages during boot time can
1278 give you some hints here ["man dmesg"].) Everyone needs either a
1279 coprocessor or this emulation.
1281 If you don't have a math coprocessor, you need to say Y here; if you
1282 say Y here even though you have a coprocessor, the coprocessor will
1283 be used nevertheless. (This behavior can be changed with the kernel
1284 command line option "no387", which comes handy if your coprocessor
1285 is broken. Try "man bootparam" or see the documentation of your boot
1286 loader (lilo or loadlin) about how to pass options to the kernel at
1287 boot time.) This means that it is a good idea to say Y here if you
1288 intend to use this kernel on different machines.
1290 More information about the internals of the Linux math coprocessor
1291 emulation can be found in <file:arch/x86/math-emu/README>.
1293 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1294 kernel, it won't hurt.
1297 bool "MTRR (Memory Type Range Register) support"
1299 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1300 the Memory Type Range Registers (MTRRs) may be used to control
1301 processor access to memory ranges. This is most useful if you have
1302 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1303 allows bus write transfers to be combined into a larger transfer
1304 before bursting over the PCI/AGP bus. This can increase performance
1305 of image write operations 2.5 times or more. Saying Y here creates a
1306 /proc/mtrr file which may be used to manipulate your processor's
1307 MTRRs. Typically the X server should use this.
1309 This code has a reasonably generic interface so that similar
1310 control registers on other processors can be easily supported
1313 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1314 Registers (ARRs) which provide a similar functionality to MTRRs. For
1315 these, the ARRs are used to emulate the MTRRs.
1316 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1317 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1318 write-combining. All of these processors are supported by this code
1319 and it makes sense to say Y here if you have one of them.
1321 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1322 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1323 can lead to all sorts of problems, so it's good to say Y here.
1325 You can safely say Y even if your machine doesn't have MTRRs, you'll
1326 just add about 9 KB to your kernel.
1328 See <file:Documentation/x86/mtrr.txt> for more information.
1330 config MTRR_SANITIZER
1332 prompt "MTRR cleanup support"
1335 Convert MTRR layout from continuous to discrete, so X drivers can
1336 add writeback entries.
1338 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1339 The largest mtrr entry size for a continuous block can be set with
1344 config MTRR_SANITIZER_ENABLE_DEFAULT
1345 int "MTRR cleanup enable value (0-1)"
1348 depends on MTRR_SANITIZER
1350 Enable mtrr cleanup default value
1352 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1353 int "MTRR cleanup spare reg num (0-7)"
1356 depends on MTRR_SANITIZER
1358 mtrr cleanup spare entries default, it can be changed via
1359 mtrr_spare_reg_nr=N on the kernel command line.
1363 prompt "x86 PAT support"
1366 Use PAT attributes to setup page level cache control.
1368 PATs are the modern equivalents of MTRRs and are much more
1369 flexible than MTRRs.
1371 Say N here if you see bootup problems (boot crash, boot hang,
1372 spontaneous reboots) or a non-working video driver.
1377 bool "EFI runtime service support"
1380 This enables the kernel to use EFI runtime services that are
1381 available (such as the EFI variable services).
1383 This option is only useful on systems that have EFI firmware.
1384 In addition, you should use the latest ELILO loader available
1385 at <http://elilo.sourceforge.net> in order to take advantage
1386 of EFI runtime services. However, even with this option, the
1387 resultant kernel should continue to boot on existing non-EFI
1392 prompt "Enable seccomp to safely compute untrusted bytecode"
1394 This kernel feature is useful for number crunching applications
1395 that may need to compute untrusted bytecode during their
1396 execution. By using pipes or other transports made available to
1397 the process as file descriptors supporting the read/write
1398 syscalls, it's possible to isolate those applications in
1399 their own address space using seccomp. Once seccomp is
1400 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1401 and the task is only allowed to execute a few safe syscalls
1402 defined by each seccomp mode.
1404 If unsure, say Y. Only embedded should say N here.
1406 config CC_STACKPROTECTOR_ALL
1409 config CC_STACKPROTECTOR
1410 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1411 select CC_STACKPROTECTOR_ALL
1413 This option turns on the -fstack-protector GCC feature. This
1414 feature puts, at the beginning of functions, a canary value on
1415 the stack just before the return address, and validates
1416 the value just before actually returning. Stack based buffer
1417 overflows (that need to overwrite this return address) now also
1418 overwrite the canary, which gets detected and the attack is then
1419 neutralized via a kernel panic.
1421 This feature requires gcc version 4.2 or above, or a distribution
1422 gcc with the feature backported. Older versions are automatically
1423 detected and for those versions, this configuration option is
1424 ignored. (and a warning is printed during bootup)
1426 source kernel/Kconfig.hz
1429 bool "kexec system call"
1431 kexec is a system call that implements the ability to shutdown your
1432 current kernel, and to start another kernel. It is like a reboot
1433 but it is independent of the system firmware. And like a reboot
1434 you can start any kernel with it, not just Linux.
1436 The name comes from the similarity to the exec system call.
1438 It is an ongoing process to be certain the hardware in a machine
1439 is properly shutdown, so do not be surprised if this code does not
1440 initially work for you. It may help to enable device hotplugging
1441 support. As of this writing the exact hardware interface is
1442 strongly in flux, so no good recommendation can be made.
1445 bool "kernel crash dumps"
1446 depends on X86_64 || (X86_32 && HIGHMEM)
1448 Generate crash dump after being started by kexec.
1449 This should be normally only set in special crash dump kernels
1450 which are loaded in the main kernel with kexec-tools into
1451 a specially reserved region and then later executed after
1452 a crash by kdump/kexec. The crash dump kernel must be compiled
1453 to a memory address not used by the main kernel or BIOS using
1454 PHYSICAL_START, or it must be built as a relocatable image
1455 (CONFIG_RELOCATABLE=y).
1456 For more details see Documentation/kdump/kdump.txt
1459 bool "kexec jump (EXPERIMENTAL)"
1460 depends on EXPERIMENTAL
1461 depends on KEXEC && HIBERNATION
1463 Jump between original kernel and kexeced kernel and invoke
1464 code in physical address mode via KEXEC
1466 config PHYSICAL_START
1467 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1470 This gives the physical address where the kernel is loaded.
1472 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1473 bzImage will decompress itself to above physical address and
1474 run from there. Otherwise, bzImage will run from the address where
1475 it has been loaded by the boot loader and will ignore above physical
1478 In normal kdump cases one does not have to set/change this option
1479 as now bzImage can be compiled as a completely relocatable image
1480 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1481 address. This option is mainly useful for the folks who don't want
1482 to use a bzImage for capturing the crash dump and want to use a
1483 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1484 to be specifically compiled to run from a specific memory area
1485 (normally a reserved region) and this option comes handy.
1487 So if you are using bzImage for capturing the crash dump,
1488 leave the value here unchanged to 0x1000000 and set
1489 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1490 for capturing the crash dump change this value to start of
1491 the reserved region. In other words, it can be set based on
1492 the "X" value as specified in the "crashkernel=YM@XM"
1493 command line boot parameter passed to the panic-ed
1494 kernel. Please take a look at Documentation/kdump/kdump.txt
1495 for more details about crash dumps.
1497 Usage of bzImage for capturing the crash dump is recommended as
1498 one does not have to build two kernels. Same kernel can be used
1499 as production kernel and capture kernel. Above option should have
1500 gone away after relocatable bzImage support is introduced. But it
1501 is present because there are users out there who continue to use
1502 vmlinux for dump capture. This option should go away down the
1505 Don't change this unless you know what you are doing.
1508 bool "Build a relocatable kernel"
1511 This builds a kernel image that retains relocation information
1512 so it can be loaded someplace besides the default 1MB.
1513 The relocations tend to make the kernel binary about 10% larger,
1514 but are discarded at runtime.
1516 One use is for the kexec on panic case where the recovery kernel
1517 must live at a different physical address than the primary
1520 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1521 it has been loaded at and the compile time physical address
1522 (CONFIG_PHYSICAL_START) is ignored.
1524 # Relocation on x86-32 needs some additional build support
1525 config X86_NEED_RELOCS
1527 depends on X86_32 && RELOCATABLE
1529 config PHYSICAL_ALIGN
1531 prompt "Alignment value to which kernel should be aligned" if X86_32
1533 range 0x2000 0x1000000
1535 This value puts the alignment restrictions on physical address
1536 where kernel is loaded and run from. Kernel is compiled for an
1537 address which meets above alignment restriction.
1539 If bootloader loads the kernel at a non-aligned address and
1540 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1541 address aligned to above value and run from there.
1543 If bootloader loads the kernel at a non-aligned address and
1544 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1545 load address and decompress itself to the address it has been
1546 compiled for and run from there. The address for which kernel is
1547 compiled already meets above alignment restrictions. Hence the
1548 end result is that kernel runs from a physical address meeting
1549 above alignment restrictions.
1551 Don't change this unless you know what you are doing.
1554 bool "Support for hot-pluggable CPUs"
1555 depends on SMP && HOTPLUG
1557 Say Y here to allow turning CPUs off and on. CPUs can be
1558 controlled through /sys/devices/system/cpu.
1559 ( Note: power management support will enable this option
1560 automatically on SMP systems. )
1561 Say N if you want to disable CPU hotplug.
1565 prompt "Compat VDSO support"
1566 depends on X86_32 || IA32_EMULATION
1568 Map the 32-bit VDSO to the predictable old-style address too.
1570 Say N here if you are running a sufficiently recent glibc
1571 version (2.3.3 or later), to remove the high-mapped
1572 VDSO mapping and to exclusively use the randomized VDSO.
1577 bool "Built-in kernel command line"
1580 Allow for specifying boot arguments to the kernel at
1581 build time. On some systems (e.g. embedded ones), it is
1582 necessary or convenient to provide some or all of the
1583 kernel boot arguments with the kernel itself (that is,
1584 to not rely on the boot loader to provide them.)
1586 To compile command line arguments into the kernel,
1587 set this option to 'Y', then fill in the
1588 the boot arguments in CONFIG_CMDLINE.
1590 Systems with fully functional boot loaders (i.e. non-embedded)
1591 should leave this option set to 'N'.
1594 string "Built-in kernel command string"
1595 depends on CMDLINE_BOOL
1598 Enter arguments here that should be compiled into the kernel
1599 image and used at boot time. If the boot loader provides a
1600 command line at boot time, it is appended to this string to
1601 form the full kernel command line, when the system boots.
1603 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1604 change this behavior.
1606 In most cases, the command line (whether built-in or provided
1607 by the boot loader) should specify the device for the root
1610 config CMDLINE_OVERRIDE
1611 bool "Built-in command line overrides boot loader arguments"
1613 depends on CMDLINE_BOOL
1615 Set this option to 'Y' to have the kernel ignore the boot loader
1616 command line, and use ONLY the built-in command line.
1618 This is used to work around broken boot loaders. This should
1619 be set to 'N' under normal conditions.
1623 config ARCH_ENABLE_MEMORY_HOTPLUG
1625 depends on X86_64 || (X86_32 && HIGHMEM)
1627 config ARCH_ENABLE_MEMORY_HOTREMOVE
1629 depends on MEMORY_HOTPLUG
1631 config HAVE_ARCH_EARLY_PFN_TO_NID
1635 menu "Power management and ACPI options"
1637 config ARCH_HIBERNATION_HEADER
1639 depends on X86_64 && HIBERNATION
1641 source "kernel/power/Kconfig"
1643 source "drivers/acpi/Kconfig"
1648 depends on APM || APM_MODULE
1651 tristate "APM (Advanced Power Management) BIOS support"
1652 depends on X86_32 && PM_SLEEP
1654 APM is a BIOS specification for saving power using several different
1655 techniques. This is mostly useful for battery powered laptops with
1656 APM compliant BIOSes. If you say Y here, the system time will be
1657 reset after a RESUME operation, the /proc/apm device will provide
1658 battery status information, and user-space programs will receive
1659 notification of APM "events" (e.g. battery status change).
1661 If you select "Y" here, you can disable actual use of the APM
1662 BIOS by passing the "apm=off" option to the kernel at boot time.
1664 Note that the APM support is almost completely disabled for
1665 machines with more than one CPU.
1667 In order to use APM, you will need supporting software. For location
1668 and more information, read <file:Documentation/power/pm.txt> and the
1669 Battery Powered Linux mini-HOWTO, available from
1670 <http://www.tldp.org/docs.html#howto>.
1672 This driver does not spin down disk drives (see the hdparm(8)
1673 manpage ("man 8 hdparm") for that), and it doesn't turn off
1674 VESA-compliant "green" monitors.
1676 This driver does not support the TI 4000M TravelMate and the ACER
1677 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1678 desktop machines also don't have compliant BIOSes, and this driver
1679 may cause those machines to panic during the boot phase.
1681 Generally, if you don't have a battery in your machine, there isn't
1682 much point in using this driver and you should say N. If you get
1683 random kernel OOPSes or reboots that don't seem to be related to
1684 anything, try disabling/enabling this option (or disabling/enabling
1687 Some other things you should try when experiencing seemingly random,
1690 1) make sure that you have enough swap space and that it is
1692 2) pass the "no-hlt" option to the kernel
1693 3) switch on floating point emulation in the kernel and pass
1694 the "no387" option to the kernel
1695 4) pass the "floppy=nodma" option to the kernel
1696 5) pass the "mem=4M" option to the kernel (thereby disabling
1697 all but the first 4 MB of RAM)
1698 6) make sure that the CPU is not over clocked.
1699 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1700 8) disable the cache from your BIOS settings
1701 9) install a fan for the video card or exchange video RAM
1702 10) install a better fan for the CPU
1703 11) exchange RAM chips
1704 12) exchange the motherboard.
1706 To compile this driver as a module, choose M here: the
1707 module will be called apm.
1711 config APM_IGNORE_USER_SUSPEND
1712 bool "Ignore USER SUSPEND"
1714 This option will ignore USER SUSPEND requests. On machines with a
1715 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1716 series notebooks, it is necessary to say Y because of a BIOS bug.
1718 config APM_DO_ENABLE
1719 bool "Enable PM at boot time"
1721 Enable APM features at boot time. From page 36 of the APM BIOS
1722 specification: "When disabled, the APM BIOS does not automatically
1723 power manage devices, enter the Standby State, enter the Suspend
1724 State, or take power saving steps in response to CPU Idle calls."
1725 This driver will make CPU Idle calls when Linux is idle (unless this
1726 feature is turned off -- see "Do CPU IDLE calls", below). This
1727 should always save battery power, but more complicated APM features
1728 will be dependent on your BIOS implementation. You may need to turn
1729 this option off if your computer hangs at boot time when using APM
1730 support, or if it beeps continuously instead of suspending. Turn
1731 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1732 T400CDT. This is off by default since most machines do fine without
1736 bool "Make CPU Idle calls when idle"
1738 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1739 On some machines, this can activate improved power savings, such as
1740 a slowed CPU clock rate, when the machine is idle. These idle calls
1741 are made after the idle loop has run for some length of time (e.g.,
1742 333 mS). On some machines, this will cause a hang at boot time or
1743 whenever the CPU becomes idle. (On machines with more than one CPU,
1744 this option does nothing.)
1746 config APM_DISPLAY_BLANK
1747 bool "Enable console blanking using APM"
1749 Enable console blanking using the APM. Some laptops can use this to
1750 turn off the LCD backlight when the screen blanker of the Linux
1751 virtual console blanks the screen. Note that this is only used by
1752 the virtual console screen blanker, and won't turn off the backlight
1753 when using the X Window system. This also doesn't have anything to
1754 do with your VESA-compliant power-saving monitor. Further, this
1755 option doesn't work for all laptops -- it might not turn off your
1756 backlight at all, or it might print a lot of errors to the console,
1757 especially if you are using gpm.
1759 config APM_ALLOW_INTS
1760 bool "Allow interrupts during APM BIOS calls"
1762 Normally we disable external interrupts while we are making calls to
1763 the APM BIOS as a measure to lessen the effects of a badly behaving
1764 BIOS implementation. The BIOS should reenable interrupts if it
1765 needs to. Unfortunately, some BIOSes do not -- especially those in
1766 many of the newer IBM Thinkpads. If you experience hangs when you
1767 suspend, try setting this to Y. Otherwise, say N.
1771 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1773 source "drivers/cpuidle/Kconfig"
1775 source "drivers/idle/Kconfig"
1780 menu "Bus options (PCI etc.)"
1785 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1787 Find out whether you have a PCI motherboard. PCI is the name of a
1788 bus system, i.e. the way the CPU talks to the other stuff inside
1789 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1790 VESA. If you have PCI, say Y, otherwise N.
1793 prompt "PCI access mode"
1794 depends on X86_32 && PCI
1797 On PCI systems, the BIOS can be used to detect the PCI devices and
1798 determine their configuration. However, some old PCI motherboards
1799 have BIOS bugs and may crash if this is done. Also, some embedded
1800 PCI-based systems don't have any BIOS at all. Linux can also try to
1801 detect the PCI hardware directly without using the BIOS.
1803 With this option, you can specify how Linux should detect the
1804 PCI devices. If you choose "BIOS", the BIOS will be used,
1805 if you choose "Direct", the BIOS won't be used, and if you
1806 choose "MMConfig", then PCI Express MMCONFIG will be used.
1807 If you choose "Any", the kernel will try MMCONFIG, then the
1808 direct access method and falls back to the BIOS if that doesn't
1809 work. If unsure, go with the default, which is "Any".
1814 config PCI_GOMMCONFIG
1831 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1833 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1836 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1840 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1844 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1851 bool "Support mmconfig PCI config space access"
1852 depends on X86_64 && PCI && ACPI
1855 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1856 depends on PCI_MSI && ACPI && EXPERIMENTAL
1858 DMA remapping (DMAR) devices support enables independent address
1859 translations for Direct Memory Access (DMA) from devices.
1860 These DMA remapping devices are reported via ACPI tables
1861 and include PCI device scope covered by these DMA
1864 config DMAR_DEFAULT_ON
1866 prompt "Enable DMA Remapping Devices by default"
1869 Selecting this option will enable a DMAR device at boot time if
1870 one is found. If this option is not selected, DMAR support can
1871 be enabled by passing intel_iommu=on to the kernel. It is
1872 recommended you say N here while the DMAR code remains
1877 prompt "Support for Graphics workaround"
1880 Current Graphics drivers tend to use physical address
1881 for DMA and avoid using DMA APIs. Setting this config
1882 option permits the IOMMU driver to set a unity map for
1883 all the OS-visible memory. Hence the driver can continue
1884 to use physical addresses for DMA.
1886 config DMAR_FLOPPY_WA
1890 Floppy disk drivers are know to bypass DMA API calls
1891 thereby failing to work when IOMMU is enabled. This
1892 workaround will setup a 1:1 mapping for the first
1893 16M to make floppy (an ISA device) work.
1896 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1897 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1899 Supports Interrupt remapping for IO-APIC and MSI devices.
1900 To use x2apic mode in the CPU's which support x2APIC enhancements or
1901 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1903 source "drivers/pci/pcie/Kconfig"
1905 source "drivers/pci/Kconfig"
1907 # x86_64 have no ISA slots, but do have ISA-style DMA.
1916 Find out whether you have ISA slots on your motherboard. ISA is the
1917 name of a bus system, i.e. the way the CPU talks to the other stuff
1918 inside your box. Other bus systems are PCI, EISA, MicroChannel
1919 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1920 newer boards don't support it. If you have ISA, say Y, otherwise N.
1926 The Extended Industry Standard Architecture (EISA) bus was
1927 developed as an open alternative to the IBM MicroChannel bus.
1929 The EISA bus provided some of the features of the IBM MicroChannel
1930 bus while maintaining backward compatibility with cards made for
1931 the older ISA bus. The EISA bus saw limited use between 1988 and
1932 1995 when it was made obsolete by the PCI bus.
1934 Say Y here if you are building a kernel for an EISA-based machine.
1938 source "drivers/eisa/Kconfig"
1943 MicroChannel Architecture is found in some IBM PS/2 machines and
1944 laptops. It is a bus system similar to PCI or ISA. See
1945 <file:Documentation/mca.txt> (and especially the web page given
1946 there) before attempting to build an MCA bus kernel.
1948 source "drivers/mca/Kconfig"
1951 tristate "NatSemi SCx200 support"
1953 This provides basic support for National Semiconductor's
1954 (now AMD's) Geode processors. The driver probes for the
1955 PCI-IDs of several on-chip devices, so its a good dependency
1956 for other scx200_* drivers.
1958 If compiled as a module, the driver is named scx200.
1960 config SCx200HR_TIMER
1961 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1962 depends on SCx200 && GENERIC_TIME
1965 This driver provides a clocksource built upon the on-chip
1966 27MHz high-resolution timer. Its also a workaround for
1967 NSC Geode SC-1100's buggy TSC, which loses time when the
1968 processor goes idle (as is done by the scheduler). The
1969 other workaround is idle=poll boot option.
1971 config GEODE_MFGPT_TIMER
1973 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1974 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1976 This driver provides a clock event source based on the MFGPT
1977 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1978 MFGPTs have a better resolution and max interval than the
1979 generic PIT, and are suitable for use as high-res timers.
1982 bool "One Laptop Per Child support"
1985 Add support for detecting the unique features of the OLPC
1992 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1994 source "drivers/pcmcia/Kconfig"
1996 source "drivers/pci/hotplug/Kconfig"
2001 menu "Executable file formats / Emulations"
2003 source "fs/Kconfig.binfmt"
2005 config IA32_EMULATION
2006 bool "IA32 Emulation"
2008 select COMPAT_BINFMT_ELF
2010 Include code to run 32-bit programs under a 64-bit kernel. You should
2011 likely turn this on, unless you're 100% sure that you don't have any
2012 32-bit programs left.
2015 tristate "IA32 a.out support"
2016 depends on IA32_EMULATION
2018 Support old a.out binaries in the 32bit emulation.
2022 depends on IA32_EMULATION
2024 config COMPAT_FOR_U64_ALIGNMENT
2028 config SYSVIPC_COMPAT
2030 depends on COMPAT && SYSVIPC
2035 config HAVE_ATOMIC_IOMAP
2039 source "net/Kconfig"
2041 source "drivers/Kconfig"
2043 source "drivers/firmware/Kconfig"
2047 source "arch/x86/Kconfig.debug"
2049 source "security/Kconfig"
2051 source "crypto/Kconfig"
2053 source "arch/x86/kvm/Kconfig"
2055 source "lib/Kconfig"
projects / linux-2.6 / blob