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
32 select HAVE_KRETPROBES
33 select HAVE_FTRACE_MCOUNT_RECORD
34 select HAVE_DYNAMIC_FTRACE
35 select HAVE_FUNCTION_TRACER
36 select HAVE_FUNCTION_GRAPH_TRACER
37 select HAVE_FUNCTION_GRAPH_FP_TEST
38 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
39 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
40 select HAVE_FTRACE_SYSCALLS
43 select HAVE_ARCH_TRACEHOOK
44 select HAVE_GENERIC_DMA_COHERENT if X86_32
45 select HAVE_EFFICIENT_UNALIGNED_ACCESS
46 select USER_STACKTRACE_SUPPORT
47 select HAVE_DMA_API_DEBUG
48 select HAVE_KERNEL_GZIP
49 select HAVE_KERNEL_BZIP2
50 select HAVE_KERNEL_LZMA
51 select HAVE_ARCH_KMEMCHECK
55 default "elf32-i386" if X86_32
56 default "elf64-x86-64" if X86_64
60 default "arch/x86/configs/i386_defconfig" if X86_32
61 default "arch/x86/configs/x86_64_defconfig" if X86_64
66 config GENERIC_CMOS_UPDATE
69 config CLOCKSOURCE_WATCHDOG
72 config GENERIC_CLOCKEVENTS
75 config GENERIC_CLOCKEVENTS_BROADCAST
77 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
79 config LOCKDEP_SUPPORT
82 config STACKTRACE_SUPPORT
85 config HAVE_LATENCYTOP_SUPPORT
88 config FAST_CMPXCHG_LOCAL
101 config GENERIC_ISA_DMA
110 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
112 config GENERIC_BUG_RELATIVE_POINTERS
115 config GENERIC_HWEIGHT
121 config ARCH_MAY_HAVE_PC_FDC
124 config RWSEM_GENERIC_SPINLOCK
127 config RWSEM_XCHGADD_ALGORITHM
130 config ARCH_HAS_CPU_IDLE_WAIT
133 config GENERIC_CALIBRATE_DELAY
136 config GENERIC_TIME_VSYSCALL
140 config ARCH_HAS_CPU_RELAX
143 config ARCH_HAS_DEFAULT_IDLE
146 config ARCH_HAS_CACHE_LINE_SIZE
149 config HAVE_SETUP_PER_CPU_AREA
152 config HAVE_DYNAMIC_PER_CPU_AREA
155 config HAVE_CPUMASK_OF_CPU_MAP
158 config ARCH_HIBERNATION_POSSIBLE
161 config ARCH_SUSPEND_POSSIBLE
168 config ARCH_POPULATES_NODE_MAP
175 config ARCH_SUPPORTS_OPTIMIZED_INLINING
178 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
181 # Use the generic interrupt handling code in kernel/irq/:
182 config GENERIC_HARDIRQS
186 config GENERIC_HARDIRQS_NO__DO_IRQ
189 config GENERIC_IRQ_PROBE
193 config GENERIC_PENDING_IRQ
195 depends on GENERIC_HARDIRQS && SMP
198 config USE_GENERIC_SMP_HELPERS
204 depends on X86_32 && SMP
208 depends on X86_64 && SMP
215 config X86_TRAMPOLINE
217 depends on SMP || (64BIT && ACPI_SLEEP)
220 config X86_32_LAZY_GS
222 depends on X86_32 && !CC_STACKPROTECTOR
226 source "init/Kconfig"
227 source "kernel/Kconfig.freezer"
229 menu "Processor type and features"
231 source "kernel/time/Kconfig"
234 bool "Symmetric multi-processing support"
236 This enables support for systems with more than one CPU. If you have
237 a system with only one CPU, like most personal computers, say N. If
238 you have a system with more than one CPU, say Y.
240 If you say N here, the kernel will run on single and multiprocessor
241 machines, but will use only one CPU of a multiprocessor machine. If
242 you say Y here, the kernel will run on many, but not all,
243 singleprocessor machines. On a singleprocessor machine, the kernel
244 will run faster if you say N here.
246 Note that if you say Y here and choose architecture "586" or
247 "Pentium" under "Processor family", the kernel will not work on 486
248 architectures. Similarly, multiprocessor kernels for the "PPro"
249 architecture may not work on all Pentium based boards.
251 People using multiprocessor machines who say Y here should also say
252 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
253 Management" code will be disabled if you say Y here.
255 See also <file:Documentation/i386/IO-APIC.txt>,
256 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
257 <http://www.tldp.org/docs.html#howto>.
259 If you don't know what to do here, say N.
262 bool "Support x2apic"
263 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
265 This enables x2apic support on CPUs that have this feature.
267 This allows 32-bit apic IDs (so it can support very large systems),
268 and accesses the local apic via MSRs not via mmio.
270 If you don't know what to do here, say N.
273 bool "Support sparse irq numbering"
274 depends on PCI_MSI || HT_IRQ
276 This enables support for sparse irqs. This is useful for distro
277 kernels that want to define a high CONFIG_NR_CPUS value but still
278 want to have low kernel memory footprint on smaller machines.
280 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
281 out the irq_desc[] array in a more NUMA-friendly way. )
283 If you don't know what to do here, say N.
287 depends on SPARSE_IRQ && NUMA
290 bool "Enable MPS table" if ACPI
292 depends on X86_LOCAL_APIC
294 For old smp systems that do not have proper acpi support. Newer systems
295 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
298 bool "Support for big SMP systems with more than 8 CPUs"
299 depends on X86_32 && SMP
301 This option is needed for the systems that have more than 8 CPUs
304 config X86_EXTENDED_PLATFORM
305 bool "Support for extended (non-PC) x86 platforms"
308 If you disable this option then the kernel will only support
309 standard PC platforms. (which covers the vast majority of
312 If you enable this option then you'll be able to select support
313 for the following (non-PC) 32 bit x86 platforms:
317 SGI 320/540 (Visual Workstation)
318 Summit/EXA (IBM x440)
319 Unisys ES7000 IA32 series
321 If you have one of these systems, or if you want to build a
322 generic distribution kernel, say Y here - otherwise say N.
326 config X86_EXTENDED_PLATFORM
327 bool "Support for extended (non-PC) x86 platforms"
330 If you disable this option then the kernel will only support
331 standard PC platforms. (which covers the vast majority of
334 If you enable this option then you'll be able to select support
335 for the following (non-PC) 64 bit x86 platforms:
339 If you have one of these systems, or if you want to build a
340 generic distribution kernel, say Y here - otherwise say N.
342 # This is an alphabetically sorted list of 64 bit extended platforms
343 # Please maintain the alphabetic order if and when there are additions
348 depends on X86_64 && PCI
349 depends on X86_EXTENDED_PLATFORM
351 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
352 supposed to run on these EM64T-based machines. Only choose this option
353 if you have one of these machines.
356 bool "SGI Ultraviolet"
358 depends on X86_EXTENDED_PLATFORM
360 depends on X86_X2APIC
362 This option is needed in order to support SGI Ultraviolet systems.
363 If you don't have one of these, you should say N here.
365 # Following is an alphabetically sorted list of 32 bit extended platforms
366 # Please maintain the alphabetic order if and when there are additions
371 depends on X86_EXTENDED_PLATFORM
373 Select this for an AMD Elan processor.
375 Do not use this option for K6/Athlon/Opteron processors!
377 If unsure, choose "PC-compatible" instead.
380 bool "RDC R-321x SoC"
382 depends on X86_EXTENDED_PLATFORM
384 select X86_REBOOTFIXUPS
386 This option is needed for RDC R-321x system-on-chip, also known
388 If you don't have one of these chips, you should say N here.
390 config X86_32_NON_STANDARD
391 bool "Support non-standard 32-bit SMP architectures"
392 depends on X86_32 && SMP
393 depends on X86_EXTENDED_PLATFORM
395 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
396 subarchitectures. It is intended for a generic binary kernel.
397 if you select them all, kernel will probe it one by one. and will
400 # Alphabetically sorted list of Non standard 32 bit platforms
403 bool "NUMAQ (IBM/Sequent)"
404 depends on X86_32_NON_STANDARD
408 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
409 NUMA multiquad box. This changes the way that processors are
410 bootstrapped, and uses Clustered Logical APIC addressing mode instead
411 of Flat Logical. You will need a new lynxer.elf file to flash your
412 firmware with - send email to <Martin.Bligh@us.ibm.com>.
415 bool "SGI 320/540 (Visual Workstation)"
416 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
417 depends on X86_32_NON_STANDARD
419 The SGI Visual Workstation series is an IA32-based workstation
420 based on SGI systems chips with some legacy PC hardware attached.
422 Say Y here to create a kernel to run on the SGI 320 or 540.
424 A kernel compiled for the Visual Workstation will run on general
425 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
428 bool "Summit/EXA (IBM x440)"
429 depends on X86_32_NON_STANDARD
431 This option is needed for IBM systems that use the Summit/EXA chipset.
432 In particular, it is needed for the x440.
435 bool "Unisys ES7000 IA32 series"
436 depends on X86_32_NON_STANDARD && X86_BIGSMP
438 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
439 supposed to run on an IA32-based Unisys ES7000 system.
441 config SCHED_OMIT_FRAME_POINTER
443 prompt "Single-depth WCHAN output"
446 Calculate simpler /proc/<PID>/wchan values. If this option
447 is disabled then wchan values will recurse back to the
448 caller function. This provides more accurate wchan values,
449 at the expense of slightly more scheduling overhead.
451 If in doubt, say "Y".
453 menuconfig PARAVIRT_GUEST
454 bool "Paravirtualized guest support"
456 Say Y here to get to see options related to running Linux under
457 various hypervisors. This option alone does not add any kernel code.
459 If you say N, all options in this submenu will be skipped and disabled.
463 source "arch/x86/xen/Kconfig"
466 bool "VMI Guest support"
470 VMI provides a paravirtualized interface to the VMware ESX server
471 (it could be used by other hypervisors in theory too, but is not
472 at the moment), by linking the kernel to a GPL-ed ROM module
473 provided by the hypervisor.
476 bool "KVM paravirtualized clock"
478 select PARAVIRT_CLOCK
480 Turning on this option will allow you to run a paravirtualized clock
481 when running over the KVM hypervisor. Instead of relying on a PIT
482 (or probably other) emulation by the underlying device model, the host
483 provides the guest with timing infrastructure such as time of day, and
487 bool "KVM Guest support"
490 This option enables various optimizations for running under the KVM
493 source "arch/x86/lguest/Kconfig"
496 bool "Enable paravirtualization code"
498 This changes the kernel so it can modify itself when it is run
499 under a hypervisor, potentially improving performance significantly
500 over full virtualization. However, when run without a hypervisor
501 the kernel is theoretically slower and slightly larger.
503 config PARAVIRT_SPINLOCKS
504 bool "Paravirtualization layer for spinlocks"
505 depends on PARAVIRT && SMP && EXPERIMENTAL
507 Paravirtualized spinlocks allow a pvops backend to replace the
508 spinlock implementation with something virtualization-friendly
509 (for example, block the virtual CPU rather than spinning).
511 Unfortunately the downside is an up to 5% performance hit on
512 native kernels, with various workloads.
514 If you are unsure how to answer this question, answer N.
516 config PARAVIRT_CLOCK
522 config PARAVIRT_DEBUG
523 bool "paravirt-ops debugging"
524 depends on PARAVIRT && DEBUG_KERNEL
526 Enable to debug paravirt_ops internals. Specifically, BUG if
527 a paravirt_op is missing when it is called.
532 This option adds a kernel parameter 'memtest', which allows memtest
534 memtest=0, mean disabled; -- default
535 memtest=1, mean do 1 test pattern;
537 memtest=4, mean do 4 test patterns.
538 If you are unsure how to answer this question, answer N.
540 config X86_SUMMIT_NUMA
542 depends on X86_32 && NUMA && X86_32_NON_STANDARD
544 config X86_CYCLONE_TIMER
546 depends on X86_32_NON_STANDARD
548 source "arch/x86/Kconfig.cpu"
552 prompt "HPET Timer Support" if X86_32
554 Use the IA-PC HPET (High Precision Event Timer) to manage
555 time in preference to the PIT and RTC, if a HPET is
557 HPET is the next generation timer replacing legacy 8254s.
558 The HPET provides a stable time base on SMP
559 systems, unlike the TSC, but it is more expensive to access,
560 as it is off-chip. You can find the HPET spec at
561 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
563 You can safely choose Y here. However, HPET will only be
564 activated if the platform and the BIOS support this feature.
565 Otherwise the 8254 will be used for timing services.
567 Choose N to continue using the legacy 8254 timer.
569 config HPET_EMULATE_RTC
571 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
573 # Mark as embedded because too many people got it wrong.
574 # The code disables itself when not needed.
577 bool "Enable DMI scanning" if EMBEDDED
579 Enabled scanning of DMI to identify machine quirks. Say Y
580 here unless you have verified that your setup is not
581 affected by entries in the DMI blacklist. Required by PNP
585 bool "GART IOMMU support" if EMBEDDED
589 depends on X86_64 && PCI
591 Support for full DMA access of devices with 32bit memory access only
592 on systems with more than 3GB. This is usually needed for USB,
593 sound, many IDE/SATA chipsets and some other devices.
594 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
595 based hardware IOMMU and a software bounce buffer based IOMMU used
596 on Intel systems and as fallback.
597 The code is only active when needed (enough memory and limited
598 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
602 bool "IBM Calgary IOMMU support"
604 depends on X86_64 && PCI && EXPERIMENTAL
606 Support for hardware IOMMUs in IBM's xSeries x366 and x460
607 systems. Needed to run systems with more than 3GB of memory
608 properly with 32-bit PCI devices that do not support DAC
609 (Double Address Cycle). Calgary also supports bus level
610 isolation, where all DMAs pass through the IOMMU. This
611 prevents them from going anywhere except their intended
612 destination. This catches hard-to-find kernel bugs and
613 mis-behaving drivers and devices that do not use the DMA-API
614 properly to set up their DMA buffers. The IOMMU can be
615 turned off at boot time with the iommu=off parameter.
616 Normally the kernel will make the right choice by itself.
619 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
621 prompt "Should Calgary be enabled by default?"
622 depends on CALGARY_IOMMU
624 Should Calgary be enabled by default? if you choose 'y', Calgary
625 will be used (if it exists). If you choose 'n', Calgary will not be
626 used even if it exists. If you choose 'n' and would like to use
627 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
631 bool "AMD IOMMU support"
634 depends on X86_64 && PCI && ACPI
636 With this option you can enable support for AMD IOMMU hardware in
637 your system. An IOMMU is a hardware component which provides
638 remapping of DMA memory accesses from devices. With an AMD IOMMU you
639 can isolate the the DMA memory of different devices and protect the
640 system from misbehaving device drivers or hardware.
642 You can find out if your system has an AMD IOMMU if you look into
643 your BIOS for an option to enable it or if you have an IVRS ACPI
646 config AMD_IOMMU_STATS
647 bool "Export AMD IOMMU statistics to debugfs"
651 This option enables code in the AMD IOMMU driver to collect various
652 statistics about whats happening in the driver and exports that
653 information to userspace via debugfs.
656 # need this always selected by IOMMU for the VIA workaround
660 Support for software bounce buffers used on x86-64 systems
661 which don't have a hardware IOMMU (e.g. the current generation
662 of Intel's x86-64 CPUs). Using this PCI devices which can only
663 access 32-bits of memory can be used on systems with more than
664 3 GB of memory. If unsure, say Y.
667 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
670 def_bool (AMD_IOMMU || DMAR)
673 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
674 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
675 select CPUMASK_OFFSTACK
678 Configure maximum number of CPUS and NUMA Nodes for this architecture.
682 int "Maximum number of CPUs" if SMP && !MAXSMP
683 range 2 8 if SMP && X86_32 && !X86_BIGSMP
684 range 2 512 if SMP && !MAXSMP
686 default "4096" if MAXSMP
687 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
690 This allows you to specify the maximum number of CPUs which this
691 kernel will support. The maximum supported value is 512 and the
692 minimum value which makes sense is 2.
694 This is purely to save memory - each supported CPU adds
695 approximately eight kilobytes to the kernel image.
698 bool "SMT (Hyperthreading) scheduler support"
701 SMT scheduler support improves the CPU scheduler's decision making
702 when dealing with Intel Pentium 4 chips with HyperThreading at a
703 cost of slightly increased overhead in some places. If unsure say
708 prompt "Multi-core scheduler support"
711 Multi-core scheduler support improves the CPU scheduler's decision
712 making when dealing with multi-core CPU chips at a cost of slightly
713 increased overhead in some places. If unsure say N here.
715 source "kernel/Kconfig.preempt"
718 bool "Local APIC support on uniprocessors"
719 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
721 A local APIC (Advanced Programmable Interrupt Controller) is an
722 integrated interrupt controller in the CPU. If you have a single-CPU
723 system which has a processor with a local APIC, you can say Y here to
724 enable and use it. If you say Y here even though your machine doesn't
725 have a local APIC, then the kernel will still run with no slowdown at
726 all. The local APIC supports CPU-generated self-interrupts (timer,
727 performance counters), and the NMI watchdog which detects hard
731 bool "IO-APIC support on uniprocessors"
732 depends on X86_UP_APIC
734 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
735 SMP-capable replacement for PC-style interrupt controllers. Most
736 SMP systems and many recent uniprocessor systems have one.
738 If you have a single-CPU system with an IO-APIC, you can say Y here
739 to use it. If you say Y here even though your machine doesn't have
740 an IO-APIC, then the kernel will still run with no slowdown at all.
742 config X86_LOCAL_APIC
744 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
745 select HAVE_PERF_COUNTERS if (!M386 && !M486)
749 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
751 config X86_VISWS_APIC
753 depends on X86_32 && X86_VISWS
755 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
756 bool "Reroute for broken boot IRQs"
758 depends on X86_IO_APIC
760 This option enables a workaround that fixes a source of
761 spurious interrupts. This is recommended when threaded
762 interrupt handling is used on systems where the generation of
763 superfluous "boot interrupts" cannot be disabled.
765 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
766 entry in the chipset's IO-APIC is masked (as, e.g. the RT
767 kernel does during interrupt handling). On chipsets where this
768 boot IRQ generation cannot be disabled, this workaround keeps
769 the original IRQ line masked so that only the equivalent "boot
770 IRQ" is delivered to the CPUs. The workaround also tells the
771 kernel to set up the IRQ handler on the boot IRQ line. In this
772 way only one interrupt is delivered to the kernel. Otherwise
773 the spurious second interrupt may cause the kernel to bring
774 down (vital) interrupt lines.
776 Only affects "broken" chipsets. Interrupt sharing may be
777 increased on these systems.
780 bool "Machine Check Exception"
782 Machine Check Exception support allows the processor to notify the
783 kernel if it detects a problem (e.g. overheating, component failure).
784 The action the kernel takes depends on the severity of the problem,
785 ranging from a warning message on the console, to halting the machine.
786 Your processor must be a Pentium or newer to support this - check the
787 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
788 have a design flaw which leads to false MCE events - hence MCE is
789 disabled on all P5 processors, unless explicitly enabled with "mce"
790 as a boot argument. Similarly, if MCE is built in and creates a
791 problem on some new non-standard machine, you can boot with "nomce"
792 to disable it. MCE support simply ignores non-MCE processors like
793 the 386 and 486, so nearly everyone can say Y here.
796 depends on X86_32 && X86_MCE
797 bool "Use legacy machine check code (will go away)"
799 select X86_ANCIENT_MCE
801 Use the old i386 machine check code. This is merely intended for
802 testing in a transition period. Try this if you run into any machine
803 check related software problems, but report the problem to
804 linux-kernel. When in doubt say no.
809 default y if (!X86_OLD_MCE && X86_32) || X86_64
813 prompt "Intel MCE features"
814 depends on X86_NEW_MCE && X86_LOCAL_APIC
816 Additional support for intel specific MCE features such as
821 prompt "AMD MCE features"
822 depends on X86_NEW_MCE && X86_LOCAL_APIC
824 Additional support for AMD specific MCE features such as
825 the DRAM Error Threshold.
827 config X86_ANCIENT_MCE
830 prompt "Support for old Pentium 5 / WinChip machine checks"
832 Include support for machine check handling on old Pentium 5 or WinChip
833 systems. These typically need to be enabled explicitely on the command
836 config X86_MCE_THRESHOLD
837 depends on X86_MCE_AMD || X86_MCE_INTEL
841 config X86_MCE_INJECT
842 depends on X86_NEW_MCE
843 tristate "Machine check injector support"
845 Provide support for injecting machine checks for testing purposes.
846 If you don't know what a machine check is and you don't do kernel
847 QA it is safe to say n.
849 config X86_MCE_NONFATAL
850 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
851 depends on X86_OLD_MCE
853 Enabling this feature starts a timer that triggers every 5 seconds which
854 will look at the machine check registers to see if anything happened.
855 Non-fatal problems automatically get corrected (but still logged).
856 Disable this if you don't want to see these messages.
857 Seeing the messages this option prints out may be indicative of dying
858 or out-of-spec (ie, overclocked) hardware.
859 This option only does something on certain CPUs.
860 (AMD Athlon/Duron and Intel Pentium 4)
862 config X86_MCE_P4THERMAL
863 bool "check for P4 thermal throttling interrupt."
864 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
866 Enabling this feature will cause a message to be printed when the P4
867 enters thermal throttling.
869 config X86_THERMAL_VECTOR
871 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
874 bool "Enable VM86 support" if EMBEDDED
878 This option is required by programs like DOSEMU to run 16-bit legacy
879 code on X86 processors. It also may be needed by software like
880 XFree86 to initialize some video cards via BIOS. Disabling this
881 option saves about 6k.
884 tristate "Toshiba Laptop support"
887 This adds a driver to safely access the System Management Mode of
888 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
889 not work on models with a Phoenix BIOS. The System Management Mode
890 is used to set the BIOS and power saving options on Toshiba portables.
892 For information on utilities to make use of this driver see the
893 Toshiba Linux utilities web site at:
894 <http://www.buzzard.org.uk/toshiba/>.
896 Say Y if you intend to run this kernel on a Toshiba portable.
900 tristate "Dell laptop support"
902 This adds a driver to safely access the System Management Mode
903 of the CPU on the Dell Inspiron 8000. The System Management Mode
904 is used to read cpu temperature and cooling fan status and to
905 control the fans on the I8K portables.
907 This driver has been tested only on the Inspiron 8000 but it may
908 also work with other Dell laptops. You can force loading on other
909 models by passing the parameter `force=1' to the module. Use at
912 For information on utilities to make use of this driver see the
913 I8K Linux utilities web site at:
914 <http://people.debian.org/~dz/i8k/>
916 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
919 config X86_REBOOTFIXUPS
920 bool "Enable X86 board specific fixups for reboot"
923 This enables chipset and/or board specific fixups to be done
924 in order to get reboot to work correctly. This is only needed on
925 some combinations of hardware and BIOS. The symptom, for which
926 this config is intended, is when reboot ends with a stalled/hung
929 Currently, the only fixup is for the Geode machines using
930 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
932 Say Y if you want to enable the fixup. Currently, it's safe to
933 enable this option even if you don't need it.
937 tristate "/dev/cpu/microcode - microcode support"
940 If you say Y here, you will be able to update the microcode on
941 certain Intel and AMD processors. The Intel support is for the
942 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
943 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
944 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
945 You will obviously need the actual microcode binary data itself
946 which is not shipped with the Linux kernel.
948 This option selects the general module only, you need to select
949 at least one vendor specific module as well.
951 To compile this driver as a module, choose M here: the
952 module will be called microcode.
954 config MICROCODE_INTEL
955 bool "Intel microcode patch loading support"
960 This options enables microcode patch loading support for Intel
963 For latest news and information on obtaining all the required
964 Intel ingredients for this driver, check:
965 <http://www.urbanmyth.org/microcode/>.
968 bool "AMD microcode patch loading support"
972 If you select this option, microcode patch loading support for AMD
973 processors will be enabled.
975 config MICROCODE_OLD_INTERFACE
980 tristate "/dev/cpu/*/msr - Model-specific register support"
982 This device gives privileged processes access to the x86
983 Model-Specific Registers (MSRs). It is a character device with
984 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
985 MSR accesses are directed to a specific CPU on multi-processor
989 tristate "/dev/cpu/*/cpuid - CPU information support"
991 This device gives processes access to the x86 CPUID instruction to
992 be executed on a specific processor. It is a character device
993 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
997 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
999 If you select this option, this will provide various x86 CPUs
1000 information through debugfs.
1003 prompt "High Memory Support"
1004 default HIGHMEM4G if !X86_NUMAQ
1005 default HIGHMEM64G if X86_NUMAQ
1010 depends on !X86_NUMAQ
1012 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1013 However, the address space of 32-bit x86 processors is only 4
1014 Gigabytes large. That means that, if you have a large amount of
1015 physical memory, not all of it can be "permanently mapped" by the
1016 kernel. The physical memory that's not permanently mapped is called
1019 If you are compiling a kernel which will never run on a machine with
1020 more than 1 Gigabyte total physical RAM, answer "off" here (default
1021 choice and suitable for most users). This will result in a "3GB/1GB"
1022 split: 3GB are mapped so that each process sees a 3GB virtual memory
1023 space and the remaining part of the 4GB virtual memory space is used
1024 by the kernel to permanently map as much physical memory as
1027 If the machine has between 1 and 4 Gigabytes physical RAM, then
1030 If more than 4 Gigabytes is used then answer "64GB" here. This
1031 selection turns Intel PAE (Physical Address Extension) mode on.
1032 PAE implements 3-level paging on IA32 processors. PAE is fully
1033 supported by Linux, PAE mode is implemented on all recent Intel
1034 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1035 then the kernel will not boot on CPUs that don't support PAE!
1037 The actual amount of total physical memory will either be
1038 auto detected or can be forced by using a kernel command line option
1039 such as "mem=256M". (Try "man bootparam" or see the documentation of
1040 your boot loader (lilo or loadlin) about how to pass options to the
1041 kernel at boot time.)
1043 If unsure, say "off".
1047 depends on !X86_NUMAQ
1049 Select this if you have a 32-bit processor and between 1 and 4
1050 gigabytes of physical RAM.
1054 depends on !M386 && !M486
1057 Select this if you have a 32-bit processor and more than 4
1058 gigabytes of physical RAM.
1063 depends on EXPERIMENTAL
1064 prompt "Memory split" if EMBEDDED
1068 Select the desired split between kernel and user memory.
1070 If the address range available to the kernel is less than the
1071 physical memory installed, the remaining memory will be available
1072 as "high memory". Accessing high memory is a little more costly
1073 than low memory, as it needs to be mapped into the kernel first.
1074 Note that increasing the kernel address space limits the range
1075 available to user programs, making the address space there
1076 tighter. Selecting anything other than the default 3G/1G split
1077 will also likely make your kernel incompatible with binary-only
1080 If you are not absolutely sure what you are doing, leave this
1084 bool "3G/1G user/kernel split"
1085 config VMSPLIT_3G_OPT
1087 bool "3G/1G user/kernel split (for full 1G low memory)"
1089 bool "2G/2G user/kernel split"
1090 config VMSPLIT_2G_OPT
1092 bool "2G/2G user/kernel split (for full 2G low memory)"
1094 bool "1G/3G user/kernel split"
1099 default 0xB0000000 if VMSPLIT_3G_OPT
1100 default 0x80000000 if VMSPLIT_2G
1101 default 0x78000000 if VMSPLIT_2G_OPT
1102 default 0x40000000 if VMSPLIT_1G
1108 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1111 bool "PAE (Physical Address Extension) Support"
1112 depends on X86_32 && !HIGHMEM4G
1114 PAE is required for NX support, and furthermore enables
1115 larger swapspace support for non-overcommit purposes. It
1116 has the cost of more pagetable lookup overhead, and also
1117 consumes more pagetable space per process.
1119 config ARCH_PHYS_ADDR_T_64BIT
1120 def_bool X86_64 || X86_PAE
1122 config DIRECT_GBPAGES
1123 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1127 Allow the kernel linear mapping to use 1GB pages on CPUs that
1128 support it. This can improve the kernel's performance a tiny bit by
1129 reducing TLB pressure. If in doubt, say "Y".
1131 # Common NUMA Features
1133 bool "Numa Memory Allocation and Scheduler Support"
1135 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1136 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1138 Enable NUMA (Non Uniform Memory Access) support.
1140 The kernel will try to allocate memory used by a CPU on the
1141 local memory controller of the CPU and add some more
1142 NUMA awareness to the kernel.
1144 For 64-bit this is recommended if the system is Intel Core i7
1145 (or later), AMD Opteron, or EM64T NUMA.
1147 For 32-bit this is only needed on (rare) 32-bit-only platforms
1148 that support NUMA topologies, such as NUMAQ / Summit, or if you
1149 boot a 32-bit kernel on a 64-bit NUMA platform.
1151 Otherwise, you should say N.
1153 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1154 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1158 prompt "Old style AMD Opteron NUMA detection"
1159 depends on X86_64 && NUMA && PCI
1161 Enable K8 NUMA node topology detection. You should say Y here if
1162 you have a multi processor AMD K8 system. This uses an old
1163 method to read the NUMA configuration directly from the builtin
1164 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1165 instead, which also takes priority if both are compiled in.
1167 config X86_64_ACPI_NUMA
1169 prompt "ACPI NUMA detection"
1170 depends on X86_64 && NUMA && ACPI && PCI
1173 Enable ACPI SRAT based node topology detection.
1175 # Some NUMA nodes have memory ranges that span
1176 # other nodes. Even though a pfn is valid and
1177 # between a node's start and end pfns, it may not
1178 # reside on that node. See memmap_init_zone()
1180 config NODES_SPAN_OTHER_NODES
1182 depends on X86_64_ACPI_NUMA
1185 bool "NUMA emulation"
1186 depends on X86_64 && NUMA
1188 Enable NUMA emulation. A flat machine will be split
1189 into virtual nodes when booted with "numa=fake=N", where N is the
1190 number of nodes. This is only useful for debugging.
1193 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1195 default "9" if MAXSMP
1196 default "6" if X86_64
1197 default "4" if X86_NUMAQ
1199 depends on NEED_MULTIPLE_NODES
1201 Specify the maximum number of NUMA Nodes available on the target
1202 system. Increases memory reserved to accommodate various tables.
1204 config HAVE_ARCH_BOOTMEM
1206 depends on X86_32 && NUMA
1208 config ARCH_HAVE_MEMORY_PRESENT
1210 depends on X86_32 && DISCONTIGMEM
1212 config NEED_NODE_MEMMAP_SIZE
1214 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1216 config HAVE_ARCH_ALLOC_REMAP
1218 depends on X86_32 && NUMA
1220 config ARCH_FLATMEM_ENABLE
1222 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1224 config ARCH_DISCONTIGMEM_ENABLE
1226 depends on NUMA && X86_32
1228 config ARCH_DISCONTIGMEM_DEFAULT
1230 depends on NUMA && X86_32
1232 config ARCH_SPARSEMEM_DEFAULT
1236 config ARCH_SPARSEMEM_ENABLE
1238 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1239 select SPARSEMEM_STATIC if X86_32
1240 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1242 config ARCH_SELECT_MEMORY_MODEL
1244 depends on ARCH_SPARSEMEM_ENABLE
1246 config ARCH_MEMORY_PROBE
1248 depends on MEMORY_HOTPLUG
1253 bool "Allocate 3rd-level pagetables from highmem"
1254 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1256 The VM uses one page table entry for each page of physical memory.
1257 For systems with a lot of RAM, this can be wasteful of precious
1258 low memory. Setting this option will put user-space page table
1259 entries in high memory.
1261 config X86_CHECK_BIOS_CORRUPTION
1262 bool "Check for low memory corruption"
1264 Periodically check for memory corruption in low memory, which
1265 is suspected to be caused by BIOS. Even when enabled in the
1266 configuration, it is disabled at runtime. Enable it by
1267 setting "memory_corruption_check=1" on the kernel command
1268 line. By default it scans the low 64k of memory every 60
1269 seconds; see the memory_corruption_check_size and
1270 memory_corruption_check_period parameters in
1271 Documentation/kernel-parameters.txt to adjust this.
1273 When enabled with the default parameters, this option has
1274 almost no overhead, as it reserves a relatively small amount
1275 of memory and scans it infrequently. It both detects corruption
1276 and prevents it from affecting the running system.
1278 It is, however, intended as a diagnostic tool; if repeatable
1279 BIOS-originated corruption always affects the same memory,
1280 you can use memmap= to prevent the kernel from using that
1283 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1284 bool "Set the default setting of memory_corruption_check"
1285 depends on X86_CHECK_BIOS_CORRUPTION
1288 Set whether the default state of memory_corruption_check is
1291 config X86_RESERVE_LOW_64K
1292 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1295 Reserve the first 64K of physical RAM on BIOSes that are known
1296 to potentially corrupt that memory range. A numbers of BIOSes are
1297 known to utilize this area during suspend/resume, so it must not
1298 be used by the kernel.
1300 Set this to N if you are absolutely sure that you trust the BIOS
1301 to get all its memory reservations and usages right.
1303 If you have doubts about the BIOS (e.g. suspend/resume does not
1304 work or there's kernel crashes after certain hardware hotplug
1305 events) and it's not AMI or Phoenix, then you might want to enable
1306 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1307 corruption patterns.
1311 config MATH_EMULATION
1313 prompt "Math emulation" if X86_32
1315 Linux can emulate a math coprocessor (used for floating point
1316 operations) if you don't have one. 486DX and Pentium processors have
1317 a math coprocessor built in, 486SX and 386 do not, unless you added
1318 a 487DX or 387, respectively. (The messages during boot time can
1319 give you some hints here ["man dmesg"].) Everyone needs either a
1320 coprocessor or this emulation.
1322 If you don't have a math coprocessor, you need to say Y here; if you
1323 say Y here even though you have a coprocessor, the coprocessor will
1324 be used nevertheless. (This behavior can be changed with the kernel
1325 command line option "no387", which comes handy if your coprocessor
1326 is broken. Try "man bootparam" or see the documentation of your boot
1327 loader (lilo or loadlin) about how to pass options to the kernel at
1328 boot time.) This means that it is a good idea to say Y here if you
1329 intend to use this kernel on different machines.
1331 More information about the internals of the Linux math coprocessor
1332 emulation can be found in <file:arch/x86/math-emu/README>.
1334 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1335 kernel, it won't hurt.
1338 bool "MTRR (Memory Type Range Register) support"
1340 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1341 the Memory Type Range Registers (MTRRs) may be used to control
1342 processor access to memory ranges. This is most useful if you have
1343 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1344 allows bus write transfers to be combined into a larger transfer
1345 before bursting over the PCI/AGP bus. This can increase performance
1346 of image write operations 2.5 times or more. Saying Y here creates a
1347 /proc/mtrr file which may be used to manipulate your processor's
1348 MTRRs. Typically the X server should use this.
1350 This code has a reasonably generic interface so that similar
1351 control registers on other processors can be easily supported
1354 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1355 Registers (ARRs) which provide a similar functionality to MTRRs. For
1356 these, the ARRs are used to emulate the MTRRs.
1357 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1358 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1359 write-combining. All of these processors are supported by this code
1360 and it makes sense to say Y here if you have one of them.
1362 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1363 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1364 can lead to all sorts of problems, so it's good to say Y here.
1366 You can safely say Y even if your machine doesn't have MTRRs, you'll
1367 just add about 9 KB to your kernel.
1369 See <file:Documentation/x86/mtrr.txt> for more information.
1371 config MTRR_SANITIZER
1373 prompt "MTRR cleanup support"
1376 Convert MTRR layout from continuous to discrete, so X drivers can
1377 add writeback entries.
1379 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1380 The largest mtrr entry size for a continuous block can be set with
1385 config MTRR_SANITIZER_ENABLE_DEFAULT
1386 int "MTRR cleanup enable value (0-1)"
1389 depends on MTRR_SANITIZER
1391 Enable mtrr cleanup default value
1393 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1394 int "MTRR cleanup spare reg num (0-7)"
1397 depends on MTRR_SANITIZER
1399 mtrr cleanup spare entries default, it can be changed via
1400 mtrr_spare_reg_nr=N on the kernel command line.
1404 prompt "x86 PAT support"
1407 Use PAT attributes to setup page level cache control.
1409 PATs are the modern equivalents of MTRRs and are much more
1410 flexible than MTRRs.
1412 Say N here if you see bootup problems (boot crash, boot hang,
1413 spontaneous reboots) or a non-working video driver.
1418 bool "EFI runtime service support"
1421 This enables the kernel to use EFI runtime services that are
1422 available (such as the EFI variable services).
1424 This option is only useful on systems that have EFI firmware.
1425 In addition, you should use the latest ELILO loader available
1426 at <http://elilo.sourceforge.net> in order to take advantage
1427 of EFI runtime services. However, even with this option, the
1428 resultant kernel should continue to boot on existing non-EFI
1433 prompt "Enable seccomp to safely compute untrusted bytecode"
1435 This kernel feature is useful for number crunching applications
1436 that may need to compute untrusted bytecode during their
1437 execution. By using pipes or other transports made available to
1438 the process as file descriptors supporting the read/write
1439 syscalls, it's possible to isolate those applications in
1440 their own address space using seccomp. Once seccomp is
1441 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1442 and the task is only allowed to execute a few safe syscalls
1443 defined by each seccomp mode.
1445 If unsure, say Y. Only embedded should say N here.
1447 config CC_STACKPROTECTOR_ALL
1450 config CC_STACKPROTECTOR
1451 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1452 select CC_STACKPROTECTOR_ALL
1454 This option turns on the -fstack-protector GCC feature. This
1455 feature puts, at the beginning of functions, a canary value on
1456 the stack just before the return address, and validates
1457 the value just before actually returning. Stack based buffer
1458 overflows (that need to overwrite this return address) now also
1459 overwrite the canary, which gets detected and the attack is then
1460 neutralized via a kernel panic.
1462 This feature requires gcc version 4.2 or above, or a distribution
1463 gcc with the feature backported. Older versions are automatically
1464 detected and for those versions, this configuration option is
1465 ignored. (and a warning is printed during bootup)
1467 source kernel/Kconfig.hz
1470 bool "kexec system call"
1472 kexec is a system call that implements the ability to shutdown your
1473 current kernel, and to start another kernel. It is like a reboot
1474 but it is independent of the system firmware. And like a reboot
1475 you can start any kernel with it, not just Linux.
1477 The name comes from the similarity to the exec system call.
1479 It is an ongoing process to be certain the hardware in a machine
1480 is properly shutdown, so do not be surprised if this code does not
1481 initially work for you. It may help to enable device hotplugging
1482 support. As of this writing the exact hardware interface is
1483 strongly in flux, so no good recommendation can be made.
1486 bool "kernel crash dumps"
1487 depends on X86_64 || (X86_32 && HIGHMEM)
1489 Generate crash dump after being started by kexec.
1490 This should be normally only set in special crash dump kernels
1491 which are loaded in the main kernel with kexec-tools into
1492 a specially reserved region and then later executed after
1493 a crash by kdump/kexec. The crash dump kernel must be compiled
1494 to a memory address not used by the main kernel or BIOS using
1495 PHYSICAL_START, or it must be built as a relocatable image
1496 (CONFIG_RELOCATABLE=y).
1497 For more details see Documentation/kdump/kdump.txt
1500 bool "kexec jump (EXPERIMENTAL)"
1501 depends on EXPERIMENTAL
1502 depends on KEXEC && HIBERNATION
1504 Jump between original kernel and kexeced kernel and invoke
1505 code in physical address mode via KEXEC
1507 config PHYSICAL_START
1508 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1511 This gives the physical address where the kernel is loaded.
1513 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1514 bzImage will decompress itself to above physical address and
1515 run from there. Otherwise, bzImage will run from the address where
1516 it has been loaded by the boot loader and will ignore above physical
1519 In normal kdump cases one does not have to set/change this option
1520 as now bzImage can be compiled as a completely relocatable image
1521 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1522 address. This option is mainly useful for the folks who don't want
1523 to use a bzImage for capturing the crash dump and want to use a
1524 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1525 to be specifically compiled to run from a specific memory area
1526 (normally a reserved region) and this option comes handy.
1528 So if you are using bzImage for capturing the crash dump,
1529 leave the value here unchanged to 0x1000000 and set
1530 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1531 for capturing the crash dump change this value to start of
1532 the reserved region. In other words, it can be set based on
1533 the "X" value as specified in the "crashkernel=YM@XM"
1534 command line boot parameter passed to the panic-ed
1535 kernel. Please take a look at Documentation/kdump/kdump.txt
1536 for more details about crash dumps.
1538 Usage of bzImage for capturing the crash dump is recommended as
1539 one does not have to build two kernels. Same kernel can be used
1540 as production kernel and capture kernel. Above option should have
1541 gone away after relocatable bzImage support is introduced. But it
1542 is present because there are users out there who continue to use
1543 vmlinux for dump capture. This option should go away down the
1546 Don't change this unless you know what you are doing.
1549 bool "Build a relocatable kernel"
1552 This builds a kernel image that retains relocation information
1553 so it can be loaded someplace besides the default 1MB.
1554 The relocations tend to make the kernel binary about 10% larger,
1555 but are discarded at runtime.
1557 One use is for the kexec on panic case where the recovery kernel
1558 must live at a different physical address than the primary
1561 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1562 it has been loaded at and the compile time physical address
1563 (CONFIG_PHYSICAL_START) is ignored.
1565 # Relocation on x86-32 needs some additional build support
1566 config X86_NEED_RELOCS
1568 depends on X86_32 && RELOCATABLE
1570 config PHYSICAL_ALIGN
1572 prompt "Alignment value to which kernel should be aligned" if X86_32
1574 range 0x2000 0x1000000
1576 This value puts the alignment restrictions on physical address
1577 where kernel is loaded and run from. Kernel is compiled for an
1578 address which meets above alignment restriction.
1580 If bootloader loads the kernel at a non-aligned address and
1581 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1582 address aligned to above value and run from there.
1584 If bootloader loads the kernel at a non-aligned address and
1585 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1586 load address and decompress itself to the address it has been
1587 compiled for and run from there. The address for which kernel is
1588 compiled already meets above alignment restrictions. Hence the
1589 end result is that kernel runs from a physical address meeting
1590 above alignment restrictions.
1592 Don't change this unless you know what you are doing.
1595 bool "Support for hot-pluggable CPUs"
1596 depends on SMP && HOTPLUG
1598 Say Y here to allow turning CPUs off and on. CPUs can be
1599 controlled through /sys/devices/system/cpu.
1600 ( Note: power management support will enable this option
1601 automatically on SMP systems. )
1602 Say N if you want to disable CPU hotplug.
1606 prompt "Compat VDSO support"
1607 depends on X86_32 || IA32_EMULATION
1609 Map the 32-bit VDSO to the predictable old-style address too.
1611 Say N here if you are running a sufficiently recent glibc
1612 version (2.3.3 or later), to remove the high-mapped
1613 VDSO mapping and to exclusively use the randomized VDSO.
1618 bool "Built-in kernel command line"
1621 Allow for specifying boot arguments to the kernel at
1622 build time. On some systems (e.g. embedded ones), it is
1623 necessary or convenient to provide some or all of the
1624 kernel boot arguments with the kernel itself (that is,
1625 to not rely on the boot loader to provide them.)
1627 To compile command line arguments into the kernel,
1628 set this option to 'Y', then fill in the
1629 the boot arguments in CONFIG_CMDLINE.
1631 Systems with fully functional boot loaders (i.e. non-embedded)
1632 should leave this option set to 'N'.
1635 string "Built-in kernel command string"
1636 depends on CMDLINE_BOOL
1639 Enter arguments here that should be compiled into the kernel
1640 image and used at boot time. If the boot loader provides a
1641 command line at boot time, it is appended to this string to
1642 form the full kernel command line, when the system boots.
1644 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1645 change this behavior.
1647 In most cases, the command line (whether built-in or provided
1648 by the boot loader) should specify the device for the root
1651 config CMDLINE_OVERRIDE
1652 bool "Built-in command line overrides boot loader arguments"
1654 depends on CMDLINE_BOOL
1656 Set this option to 'Y' to have the kernel ignore the boot loader
1657 command line, and use ONLY the built-in command line.
1659 This is used to work around broken boot loaders. This should
1660 be set to 'N' under normal conditions.
1664 config ARCH_ENABLE_MEMORY_HOTPLUG
1666 depends on X86_64 || (X86_32 && HIGHMEM)
1668 config ARCH_ENABLE_MEMORY_HOTREMOVE
1670 depends on MEMORY_HOTPLUG
1672 config HAVE_ARCH_EARLY_PFN_TO_NID
1676 menu "Power management and ACPI options"
1678 config ARCH_HIBERNATION_HEADER
1680 depends on X86_64 && HIBERNATION
1682 source "kernel/power/Kconfig"
1684 source "drivers/acpi/Kconfig"
1689 depends on APM || APM_MODULE
1692 tristate "APM (Advanced Power Management) BIOS support"
1693 depends on X86_32 && PM_SLEEP
1695 APM is a BIOS specification for saving power using several different
1696 techniques. This is mostly useful for battery powered laptops with
1697 APM compliant BIOSes. If you say Y here, the system time will be
1698 reset after a RESUME operation, the /proc/apm device will provide
1699 battery status information, and user-space programs will receive
1700 notification of APM "events" (e.g. battery status change).
1702 If you select "Y" here, you can disable actual use of the APM
1703 BIOS by passing the "apm=off" option to the kernel at boot time.
1705 Note that the APM support is almost completely disabled for
1706 machines with more than one CPU.
1708 In order to use APM, you will need supporting software. For location
1709 and more information, read <file:Documentation/power/pm.txt> and the
1710 Battery Powered Linux mini-HOWTO, available from
1711 <http://www.tldp.org/docs.html#howto>.
1713 This driver does not spin down disk drives (see the hdparm(8)
1714 manpage ("man 8 hdparm") for that), and it doesn't turn off
1715 VESA-compliant "green" monitors.
1717 This driver does not support the TI 4000M TravelMate and the ACER
1718 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1719 desktop machines also don't have compliant BIOSes, and this driver
1720 may cause those machines to panic during the boot phase.
1722 Generally, if you don't have a battery in your machine, there isn't
1723 much point in using this driver and you should say N. If you get
1724 random kernel OOPSes or reboots that don't seem to be related to
1725 anything, try disabling/enabling this option (or disabling/enabling
1728 Some other things you should try when experiencing seemingly random,
1731 1) make sure that you have enough swap space and that it is
1733 2) pass the "no-hlt" option to the kernel
1734 3) switch on floating point emulation in the kernel and pass
1735 the "no387" option to the kernel
1736 4) pass the "floppy=nodma" option to the kernel
1737 5) pass the "mem=4M" option to the kernel (thereby disabling
1738 all but the first 4 MB of RAM)
1739 6) make sure that the CPU is not over clocked.
1740 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1741 8) disable the cache from your BIOS settings
1742 9) install a fan for the video card or exchange video RAM
1743 10) install a better fan for the CPU
1744 11) exchange RAM chips
1745 12) exchange the motherboard.
1747 To compile this driver as a module, choose M here: the
1748 module will be called apm.
1752 config APM_IGNORE_USER_SUSPEND
1753 bool "Ignore USER SUSPEND"
1755 This option will ignore USER SUSPEND requests. On machines with a
1756 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1757 series notebooks, it is necessary to say Y because of a BIOS bug.
1759 config APM_DO_ENABLE
1760 bool "Enable PM at boot time"
1762 Enable APM features at boot time. From page 36 of the APM BIOS
1763 specification: "When disabled, the APM BIOS does not automatically
1764 power manage devices, enter the Standby State, enter the Suspend
1765 State, or take power saving steps in response to CPU Idle calls."
1766 This driver will make CPU Idle calls when Linux is idle (unless this
1767 feature is turned off -- see "Do CPU IDLE calls", below). This
1768 should always save battery power, but more complicated APM features
1769 will be dependent on your BIOS implementation. You may need to turn
1770 this option off if your computer hangs at boot time when using APM
1771 support, or if it beeps continuously instead of suspending. Turn
1772 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1773 T400CDT. This is off by default since most machines do fine without
1777 bool "Make CPU Idle calls when idle"
1779 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1780 On some machines, this can activate improved power savings, such as
1781 a slowed CPU clock rate, when the machine is idle. These idle calls
1782 are made after the idle loop has run for some length of time (e.g.,
1783 333 mS). On some machines, this will cause a hang at boot time or
1784 whenever the CPU becomes idle. (On machines with more than one CPU,
1785 this option does nothing.)
1787 config APM_DISPLAY_BLANK
1788 bool "Enable console blanking using APM"
1790 Enable console blanking using the APM. Some laptops can use this to
1791 turn off the LCD backlight when the screen blanker of the Linux
1792 virtual console blanks the screen. Note that this is only used by
1793 the virtual console screen blanker, and won't turn off the backlight
1794 when using the X Window system. This also doesn't have anything to
1795 do with your VESA-compliant power-saving monitor. Further, this
1796 option doesn't work for all laptops -- it might not turn off your
1797 backlight at all, or it might print a lot of errors to the console,
1798 especially if you are using gpm.
1800 config APM_ALLOW_INTS
1801 bool "Allow interrupts during APM BIOS calls"
1803 Normally we disable external interrupts while we are making calls to
1804 the APM BIOS as a measure to lessen the effects of a badly behaving
1805 BIOS implementation. The BIOS should reenable interrupts if it
1806 needs to. Unfortunately, some BIOSes do not -- especially those in
1807 many of the newer IBM Thinkpads. If you experience hangs when you
1808 suspend, try setting this to Y. Otherwise, say N.
1812 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1814 source "drivers/cpuidle/Kconfig"
1816 source "drivers/idle/Kconfig"
1821 menu "Bus options (PCI etc.)"
1826 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1828 Find out whether you have a PCI motherboard. PCI is the name of a
1829 bus system, i.e. the way the CPU talks to the other stuff inside
1830 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1831 VESA. If you have PCI, say Y, otherwise N.
1834 prompt "PCI access mode"
1835 depends on X86_32 && PCI
1838 On PCI systems, the BIOS can be used to detect the PCI devices and
1839 determine their configuration. However, some old PCI motherboards
1840 have BIOS bugs and may crash if this is done. Also, some embedded
1841 PCI-based systems don't have any BIOS at all. Linux can also try to
1842 detect the PCI hardware directly without using the BIOS.
1844 With this option, you can specify how Linux should detect the
1845 PCI devices. If you choose "BIOS", the BIOS will be used,
1846 if you choose "Direct", the BIOS won't be used, and if you
1847 choose "MMConfig", then PCI Express MMCONFIG will be used.
1848 If you choose "Any", the kernel will try MMCONFIG, then the
1849 direct access method and falls back to the BIOS if that doesn't
1850 work. If unsure, go with the default, which is "Any".
1855 config PCI_GOMMCONFIG
1872 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1874 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1877 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1881 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1885 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1892 bool "Support mmconfig PCI config space access"
1893 depends on X86_64 && PCI && ACPI
1896 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1897 depends on PCI_MSI && ACPI && EXPERIMENTAL
1899 DMA remapping (DMAR) devices support enables independent address
1900 translations for Direct Memory Access (DMA) from devices.
1901 These DMA remapping devices are reported via ACPI tables
1902 and include PCI device scope covered by these DMA
1905 config DMAR_DEFAULT_ON
1907 prompt "Enable DMA Remapping Devices by default"
1910 Selecting this option will enable a DMAR device at boot time if
1911 one is found. If this option is not selected, DMAR support can
1912 be enabled by passing intel_iommu=on to the kernel. It is
1913 recommended you say N here while the DMAR code remains
1916 config DMAR_BROKEN_GFX_WA
1918 prompt "Workaround broken graphics drivers (going away soon)"
1921 Current Graphics drivers tend to use physical address
1922 for DMA and avoid using DMA APIs. Setting this config
1923 option permits the IOMMU driver to set a unity map for
1924 all the OS-visible memory. Hence the driver can continue
1925 to use physical addresses for DMA, at least until this
1926 option is removed in the 2.6.32 kernel.
1928 config DMAR_FLOPPY_WA
1932 Floppy disk drivers are known to bypass DMA API calls
1933 thereby failing to work when IOMMU is enabled. This
1934 workaround will setup a 1:1 mapping for the first
1935 16MiB to make floppy (an ISA device) work.
1938 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1939 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1941 Supports Interrupt remapping for IO-APIC and MSI devices.
1942 To use x2apic mode in the CPU's which support x2APIC enhancements or
1943 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1945 source "drivers/pci/pcie/Kconfig"
1947 source "drivers/pci/Kconfig"
1949 # x86_64 have no ISA slots, but do have ISA-style DMA.
1958 Find out whether you have ISA slots on your motherboard. ISA is the
1959 name of a bus system, i.e. the way the CPU talks to the other stuff
1960 inside your box. Other bus systems are PCI, EISA, MicroChannel
1961 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1962 newer boards don't support it. If you have ISA, say Y, otherwise N.
1968 The Extended Industry Standard Architecture (EISA) bus was
1969 developed as an open alternative to the IBM MicroChannel bus.
1971 The EISA bus provided some of the features of the IBM MicroChannel
1972 bus while maintaining backward compatibility with cards made for
1973 the older ISA bus. The EISA bus saw limited use between 1988 and
1974 1995 when it was made obsolete by the PCI bus.
1976 Say Y here if you are building a kernel for an EISA-based machine.
1980 source "drivers/eisa/Kconfig"
1985 MicroChannel Architecture is found in some IBM PS/2 machines and
1986 laptops. It is a bus system similar to PCI or ISA. See
1987 <file:Documentation/mca.txt> (and especially the web page given
1988 there) before attempting to build an MCA bus kernel.
1990 source "drivers/mca/Kconfig"
1993 tristate "NatSemi SCx200 support"
1995 This provides basic support for National Semiconductor's
1996 (now AMD's) Geode processors. The driver probes for the
1997 PCI-IDs of several on-chip devices, so its a good dependency
1998 for other scx200_* drivers.
2000 If compiled as a module, the driver is named scx200.
2002 config SCx200HR_TIMER
2003 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2004 depends on SCx200 && GENERIC_TIME
2007 This driver provides a clocksource built upon the on-chip
2008 27MHz high-resolution timer. Its also a workaround for
2009 NSC Geode SC-1100's buggy TSC, which loses time when the
2010 processor goes idle (as is done by the scheduler). The
2011 other workaround is idle=poll boot option.
2013 config GEODE_MFGPT_TIMER
2015 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2016 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2018 This driver provides a clock event source based on the MFGPT
2019 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2020 MFGPTs have a better resolution and max interval than the
2021 generic PIT, and are suitable for use as high-res timers.
2024 bool "One Laptop Per Child support"
2027 Add support for detecting the unique features of the OLPC
2034 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2036 source "drivers/pcmcia/Kconfig"
2038 source "drivers/pci/hotplug/Kconfig"
2043 menu "Executable file formats / Emulations"
2045 source "fs/Kconfig.binfmt"
2047 config IA32_EMULATION
2048 bool "IA32 Emulation"
2050 select COMPAT_BINFMT_ELF
2052 Include code to run 32-bit programs under a 64-bit kernel. You should
2053 likely turn this on, unless you're 100% sure that you don't have any
2054 32-bit programs left.
2057 tristate "IA32 a.out support"
2058 depends on IA32_EMULATION
2060 Support old a.out binaries in the 32bit emulation.
2064 depends on IA32_EMULATION
2066 config COMPAT_FOR_U64_ALIGNMENT
2070 config SYSVIPC_COMPAT
2072 depends on COMPAT && SYSVIPC
2077 config HAVE_ATOMIC_IOMAP
2081 source "net/Kconfig"
2083 source "drivers/Kconfig"
2085 source "drivers/firmware/Kconfig"
2089 source "arch/x86/Kconfig.debug"
2091 source "security/Kconfig"
2093 source "crypto/Kconfig"
2095 source "arch/x86/kvm/Kconfig"
2097 source "lib/Kconfig"
projects / linux-2.6 / blob