2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_FTRACE_SYSCALLS
41 select HAVE_ARCH_TRACEHOOK
42 select HAVE_GENERIC_DMA_COHERENT if X86_32
43 select HAVE_EFFICIENT_UNALIGNED_ACCESS
44 select USER_STACKTRACE_SUPPORT
45 select HAVE_DMA_API_DEBUG
46 select HAVE_KERNEL_GZIP
47 select HAVE_KERNEL_BZIP2
48 select HAVE_KERNEL_LZMA
52 default "arch/x86/configs/i386_defconfig" if X86_32
53 default "arch/x86/configs/x86_64_defconfig" if X86_64
58 config GENERIC_CMOS_UPDATE
61 config CLOCKSOURCE_WATCHDOG
64 config GENERIC_CLOCKEVENTS
67 config GENERIC_CLOCKEVENTS_BROADCAST
69 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
71 config LOCKDEP_SUPPORT
74 config STACKTRACE_SUPPORT
77 config HAVE_LATENCYTOP_SUPPORT
80 config FAST_CMPXCHG_LOCAL
93 config GENERIC_ISA_DMA
102 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
104 config GENERIC_BUG_RELATIVE_POINTERS
107 config GENERIC_HWEIGHT
113 config ARCH_MAY_HAVE_PC_FDC
116 config RWSEM_GENERIC_SPINLOCK
119 config RWSEM_XCHGADD_ALGORITHM
122 config ARCH_HAS_CPU_IDLE_WAIT
125 config GENERIC_CALIBRATE_DELAY
128 config GENERIC_TIME_VSYSCALL
132 config ARCH_HAS_CPU_RELAX
135 config ARCH_HAS_DEFAULT_IDLE
138 config ARCH_HAS_CACHE_LINE_SIZE
141 config HAVE_SETUP_PER_CPU_AREA
144 config HAVE_DYNAMIC_PER_CPU_AREA
147 config HAVE_CPUMASK_OF_CPU_MAP
150 config ARCH_HIBERNATION_POSSIBLE
153 config ARCH_SUSPEND_POSSIBLE
160 config ARCH_POPULATES_NODE_MAP
167 config ARCH_SUPPORTS_OPTIMIZED_INLINING
170 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
173 # Use the generic interrupt handling code in kernel/irq/:
174 config GENERIC_HARDIRQS
178 config GENERIC_HARDIRQS_NO__DO_IRQ
181 config GENERIC_IRQ_PROBE
185 config GENERIC_PENDING_IRQ
187 depends on GENERIC_HARDIRQS && SMP
190 config USE_GENERIC_SMP_HELPERS
196 depends on X86_32 && SMP
200 depends on X86_64 && SMP
207 config X86_TRAMPOLINE
209 depends on SMP || (64BIT && ACPI_SLEEP)
212 config X86_32_LAZY_GS
214 depends on X86_32 && !CC_STACKPROTECTOR
218 source "init/Kconfig"
219 source "kernel/Kconfig.freezer"
221 menu "Processor type and features"
223 source "kernel/time/Kconfig"
226 bool "Symmetric multi-processing support"
228 This enables support for systems with more than one CPU. If you have
229 a system with only one CPU, like most personal computers, say N. If
230 you have a system with more than one CPU, say Y.
232 If you say N here, the kernel will run on single and multiprocessor
233 machines, but will use only one CPU of a multiprocessor machine. If
234 you say Y here, the kernel will run on many, but not all,
235 singleprocessor machines. On a singleprocessor machine, the kernel
236 will run faster if you say N here.
238 Note that if you say Y here and choose architecture "586" or
239 "Pentium" under "Processor family", the kernel will not work on 486
240 architectures. Similarly, multiprocessor kernels for the "PPro"
241 architecture may not work on all Pentium based boards.
243 People using multiprocessor machines who say Y here should also say
244 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
245 Management" code will be disabled if you say Y here.
247 See also <file:Documentation/i386/IO-APIC.txt>,
248 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
249 <http://www.tldp.org/docs.html#howto>.
251 If you don't know what to do here, say N.
254 bool "Support x2apic"
255 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
257 This enables x2apic support on CPUs that have this feature.
259 This allows 32-bit apic IDs (so it can support very large systems),
260 and accesses the local apic via MSRs not via mmio.
262 If you don't know what to do here, say N.
265 bool "Support sparse irq numbering"
266 depends on PCI_MSI || HT_IRQ
268 This enables support for sparse irqs. This is useful for distro
269 kernels that want to define a high CONFIG_NR_CPUS value but still
270 want to have low kernel memory footprint on smaller machines.
272 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
273 out the irq_desc[] array in a more NUMA-friendly way. )
275 If you don't know what to do here, say N.
277 config NUMA_MIGRATE_IRQ_DESC
278 bool "Move irq desc when changing irq smp_affinity"
279 depends on SPARSE_IRQ && NUMA
282 This enables moving irq_desc to cpu/node that irq will use handled.
284 If you don't know what to do here, say N.
287 bool "Enable MPS table" if ACPI
289 depends on X86_LOCAL_APIC
291 For old smp systems that do not have proper acpi support. Newer systems
292 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
295 bool "Support for big SMP systems with more than 8 CPUs"
296 depends on X86_32 && SMP
298 This option is needed for the systems that have more than 8 CPUs
301 config X86_EXTENDED_PLATFORM
302 bool "Support for extended (non-PC) x86 platforms"
305 If you disable this option then the kernel will only support
306 standard PC platforms. (which covers the vast majority of
309 If you enable this option then you'll be able to select support
310 for the following (non-PC) 32 bit x86 platforms:
314 SGI 320/540 (Visual Workstation)
315 Summit/EXA (IBM x440)
316 Unisys ES7000 IA32 series
318 If you have one of these systems, or if you want to build a
319 generic distribution kernel, say Y here - otherwise say N.
323 config X86_EXTENDED_PLATFORM
324 bool "Support for extended (non-PC) x86 platforms"
327 If you disable this option then the kernel will only support
328 standard PC platforms. (which covers the vast majority of
331 If you enable this option then you'll be able to select support
332 for the following (non-PC) 64 bit x86 platforms:
336 If you have one of these systems, or if you want to build a
337 generic distribution kernel, say Y here - otherwise say N.
339 # This is an alphabetically sorted list of 64 bit extended platforms
340 # Please maintain the alphabetic order if and when there are additions
345 depends on X86_64 && PCI
346 depends on X86_EXTENDED_PLATFORM
348 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
349 supposed to run on these EM64T-based machines. Only choose this option
350 if you have one of these machines.
353 bool "SGI Ultraviolet"
355 depends on X86_EXTENDED_PLATFORM
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_CLOCK
506 config PARAVIRT_DEBUG
507 bool "paravirt-ops debugging"
508 depends on PARAVIRT && DEBUG_KERNEL
510 Enable to debug paravirt_ops internals. Specifically, BUG if
511 a paravirt_op is missing when it is called.
516 This option adds a kernel parameter 'memtest', which allows memtest
518 memtest=0, mean disabled; -- default
519 memtest=1, mean do 1 test pattern;
521 memtest=4, mean do 4 test patterns.
522 If you are unsure how to answer this question, answer N.
524 config X86_SUMMIT_NUMA
526 depends on X86_32 && NUMA && X86_32_NON_STANDARD
528 config X86_CYCLONE_TIMER
530 depends on X86_32_NON_STANDARD
532 source "arch/x86/Kconfig.cpu"
536 prompt "HPET Timer Support" if X86_32
538 Use the IA-PC HPET (High Precision Event Timer) to manage
539 time in preference to the PIT and RTC, if a HPET is
541 HPET is the next generation timer replacing legacy 8254s.
542 The HPET provides a stable time base on SMP
543 systems, unlike the TSC, but it is more expensive to access,
544 as it is off-chip. You can find the HPET spec at
545 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
547 You can safely choose Y here. However, HPET will only be
548 activated if the platform and the BIOS support this feature.
549 Otherwise the 8254 will be used for timing services.
551 Choose N to continue using the legacy 8254 timer.
553 config HPET_EMULATE_RTC
555 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
557 # Mark as embedded because too many people got it wrong.
558 # The code disables itself when not needed.
561 bool "Enable DMI scanning" if EMBEDDED
563 Enabled scanning of DMI to identify machine quirks. Say Y
564 here unless you have verified that your setup is not
565 affected by entries in the DMI blacklist. Required by PNP
569 bool "GART IOMMU support" if EMBEDDED
573 depends on X86_64 && PCI
575 Support for full DMA access of devices with 32bit memory access only
576 on systems with more than 3GB. This is usually needed for USB,
577 sound, many IDE/SATA chipsets and some other devices.
578 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
579 based hardware IOMMU and a software bounce buffer based IOMMU used
580 on Intel systems and as fallback.
581 The code is only active when needed (enough memory and limited
582 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
586 bool "IBM Calgary IOMMU support"
588 depends on X86_64 && PCI && EXPERIMENTAL
590 Support for hardware IOMMUs in IBM's xSeries x366 and x460
591 systems. Needed to run systems with more than 3GB of memory
592 properly with 32-bit PCI devices that do not support DAC
593 (Double Address Cycle). Calgary also supports bus level
594 isolation, where all DMAs pass through the IOMMU. This
595 prevents them from going anywhere except their intended
596 destination. This catches hard-to-find kernel bugs and
597 mis-behaving drivers and devices that do not use the DMA-API
598 properly to set up their DMA buffers. The IOMMU can be
599 turned off at boot time with the iommu=off parameter.
600 Normally the kernel will make the right choice by itself.
603 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
605 prompt "Should Calgary be enabled by default?"
606 depends on CALGARY_IOMMU
608 Should Calgary be enabled by default? if you choose 'y', Calgary
609 will be used (if it exists). If you choose 'n', Calgary will not be
610 used even if it exists. If you choose 'n' and would like to use
611 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
615 bool "AMD IOMMU support"
618 depends on X86_64 && PCI && ACPI
620 With this option you can enable support for AMD IOMMU hardware in
621 your system. An IOMMU is a hardware component which provides
622 remapping of DMA memory accesses from devices. With an AMD IOMMU you
623 can isolate the the DMA memory of different devices and protect the
624 system from misbehaving device drivers or hardware.
626 You can find out if your system has an AMD IOMMU if you look into
627 your BIOS for an option to enable it or if you have an IVRS ACPI
630 config AMD_IOMMU_STATS
631 bool "Export AMD IOMMU statistics to debugfs"
635 This option enables code in the AMD IOMMU driver to collect various
636 statistics about whats happening in the driver and exports that
637 information to userspace via debugfs.
640 # need this always selected by IOMMU for the VIA workaround
644 Support for software bounce buffers used on x86-64 systems
645 which don't have a hardware IOMMU (e.g. the current generation
646 of Intel's x86-64 CPUs). Using this PCI devices which can only
647 access 32-bits of memory can be used on systems with more than
648 3 GB of memory. If unsure, say Y.
651 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
654 def_bool (AMD_IOMMU || DMAR)
657 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
658 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
659 select CPUMASK_OFFSTACK
662 Configure maximum number of CPUS and NUMA Nodes for this architecture.
666 int "Maximum number of CPUs" if SMP && !MAXSMP
667 range 2 512 if SMP && !MAXSMP
669 default "4096" if MAXSMP
670 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
673 This allows you to specify the maximum number of CPUs which this
674 kernel will support. The maximum supported value is 512 and the
675 minimum value which makes sense is 2.
677 This is purely to save memory - each supported CPU adds
678 approximately eight kilobytes to the kernel image.
681 bool "SMT (Hyperthreading) scheduler support"
684 SMT scheduler support improves the CPU scheduler's decision making
685 when dealing with Intel Pentium 4 chips with HyperThreading at a
686 cost of slightly increased overhead in some places. If unsure say
691 prompt "Multi-core scheduler support"
694 Multi-core scheduler support improves the CPU scheduler's decision
695 making when dealing with multi-core CPU chips at a cost of slightly
696 increased overhead in some places. If unsure say N here.
698 source "kernel/Kconfig.preempt"
701 bool "Local APIC support on uniprocessors"
702 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
704 A local APIC (Advanced Programmable Interrupt Controller) is an
705 integrated interrupt controller in the CPU. If you have a single-CPU
706 system which has a processor with a local APIC, you can say Y here to
707 enable and use it. If you say Y here even though your machine doesn't
708 have a local APIC, then the kernel will still run with no slowdown at
709 all. The local APIC supports CPU-generated self-interrupts (timer,
710 performance counters), and the NMI watchdog which detects hard
714 bool "IO-APIC support on uniprocessors"
715 depends on X86_UP_APIC
717 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
718 SMP-capable replacement for PC-style interrupt controllers. Most
719 SMP systems and many recent uniprocessor systems have one.
721 If you have a single-CPU system with an IO-APIC, you can say Y here
722 to use it. If you say Y here even though your machine doesn't have
723 an IO-APIC, then the kernel will still run with no slowdown at all.
725 config X86_LOCAL_APIC
727 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
731 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
733 config X86_VISWS_APIC
735 depends on X86_32 && X86_VISWS
737 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
738 bool "Reroute for broken boot IRQs"
740 depends on X86_IO_APIC
742 This option enables a workaround that fixes a source of
743 spurious interrupts. This is recommended when threaded
744 interrupt handling is used on systems where the generation of
745 superfluous "boot interrupts" cannot be disabled.
747 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
748 entry in the chipset's IO-APIC is masked (as, e.g. the RT
749 kernel does during interrupt handling). On chipsets where this
750 boot IRQ generation cannot be disabled, this workaround keeps
751 the original IRQ line masked so that only the equivalent "boot
752 IRQ" is delivered to the CPUs. The workaround also tells the
753 kernel to set up the IRQ handler on the boot IRQ line. In this
754 way only one interrupt is delivered to the kernel. Otherwise
755 the spurious second interrupt may cause the kernel to bring
756 down (vital) interrupt lines.
758 Only affects "broken" chipsets. Interrupt sharing may be
759 increased on these systems.
762 bool "Machine Check Exception"
764 Machine Check Exception support allows the processor to notify the
765 kernel if it detects a problem (e.g. overheating, component failure).
766 The action the kernel takes depends on the severity of the problem,
767 ranging from a warning message on the console, to halting the machine.
768 Your processor must be a Pentium or newer to support this - check the
769 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
770 have a design flaw which leads to false MCE events - hence MCE is
771 disabled on all P5 processors, unless explicitly enabled with "mce"
772 as a boot argument. Similarly, if MCE is built in and creates a
773 problem on some new non-standard machine, you can boot with "nomce"
774 to disable it. MCE support simply ignores non-MCE processors like
775 the 386 and 486, so nearly everyone can say Y here.
779 prompt "Intel MCE features"
780 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
782 Additional support for intel specific MCE features such as
787 prompt "AMD MCE features"
788 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
790 Additional support for AMD specific MCE features such as
791 the DRAM Error Threshold.
793 config X86_MCE_THRESHOLD
794 depends on X86_MCE_AMD || X86_MCE_INTEL
798 config X86_MCE_NONFATAL
799 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
800 depends on X86_32 && X86_MCE
802 Enabling this feature starts a timer that triggers every 5 seconds which
803 will look at the machine check registers to see if anything happened.
804 Non-fatal problems automatically get corrected (but still logged).
805 Disable this if you don't want to see these messages.
806 Seeing the messages this option prints out may be indicative of dying
807 or out-of-spec (ie, overclocked) hardware.
808 This option only does something on certain CPUs.
809 (AMD Athlon/Duron and Intel Pentium 4)
811 config X86_MCE_P4THERMAL
812 bool "check for P4 thermal throttling interrupt."
813 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
815 Enabling this feature will cause a message to be printed when the P4
816 enters thermal throttling.
819 bool "Enable VM86 support" if EMBEDDED
823 This option is required by programs like DOSEMU to run 16-bit legacy
824 code on X86 processors. It also may be needed by software like
825 XFree86 to initialize some video cards via BIOS. Disabling this
826 option saves about 6k.
829 tristate "Toshiba Laptop support"
832 This adds a driver to safely access the System Management Mode of
833 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
834 not work on models with a Phoenix BIOS. The System Management Mode
835 is used to set the BIOS and power saving options on Toshiba portables.
837 For information on utilities to make use of this driver see the
838 Toshiba Linux utilities web site at:
839 <http://www.buzzard.org.uk/toshiba/>.
841 Say Y if you intend to run this kernel on a Toshiba portable.
845 tristate "Dell laptop support"
847 This adds a driver to safely access the System Management Mode
848 of the CPU on the Dell Inspiron 8000. The System Management Mode
849 is used to read cpu temperature and cooling fan status and to
850 control the fans on the I8K portables.
852 This driver has been tested only on the Inspiron 8000 but it may
853 also work with other Dell laptops. You can force loading on other
854 models by passing the parameter `force=1' to the module. Use at
857 For information on utilities to make use of this driver see the
858 I8K Linux utilities web site at:
859 <http://people.debian.org/~dz/i8k/>
861 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
864 config X86_REBOOTFIXUPS
865 bool "Enable X86 board specific fixups for reboot"
868 This enables chipset and/or board specific fixups to be done
869 in order to get reboot to work correctly. This is only needed on
870 some combinations of hardware and BIOS. The symptom, for which
871 this config is intended, is when reboot ends with a stalled/hung
874 Currently, the only fixup is for the Geode machines using
875 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
877 Say Y if you want to enable the fixup. Currently, it's safe to
878 enable this option even if you don't need it.
882 tristate "/dev/cpu/microcode - microcode support"
885 If you say Y here, you will be able to update the microcode on
886 certain Intel and AMD processors. The Intel support is for the
887 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
888 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
889 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
890 You will obviously need the actual microcode binary data itself
891 which is not shipped with the Linux kernel.
893 This option selects the general module only, you need to select
894 at least one vendor specific module as well.
896 To compile this driver as a module, choose M here: the
897 module will be called microcode.
899 config MICROCODE_INTEL
900 bool "Intel microcode patch loading support"
905 This options enables microcode patch loading support for Intel
908 For latest news and information on obtaining all the required
909 Intel ingredients for this driver, check:
910 <http://www.urbanmyth.org/microcode/>.
913 bool "AMD microcode patch loading support"
917 If you select this option, microcode patch loading support for AMD
918 processors will be enabled.
920 config MICROCODE_OLD_INTERFACE
925 tristate "/dev/cpu/*/msr - Model-specific register support"
927 This device gives privileged processes access to the x86
928 Model-Specific Registers (MSRs). It is a character device with
929 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
930 MSR accesses are directed to a specific CPU on multi-processor
934 tristate "/dev/cpu/*/cpuid - CPU information support"
936 This device gives processes access to the x86 CPUID instruction to
937 be executed on a specific processor. It is a character device
938 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
942 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
944 If you select this option, this will provide various x86 CPUs
945 information through debugfs.
948 prompt "High Memory Support"
949 default HIGHMEM4G if !X86_NUMAQ
950 default HIGHMEM64G if X86_NUMAQ
955 depends on !X86_NUMAQ
957 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
958 However, the address space of 32-bit x86 processors is only 4
959 Gigabytes large. That means that, if you have a large amount of
960 physical memory, not all of it can be "permanently mapped" by the
961 kernel. The physical memory that's not permanently mapped is called
964 If you are compiling a kernel which will never run on a machine with
965 more than 1 Gigabyte total physical RAM, answer "off" here (default
966 choice and suitable for most users). This will result in a "3GB/1GB"
967 split: 3GB are mapped so that each process sees a 3GB virtual memory
968 space and the remaining part of the 4GB virtual memory space is used
969 by the kernel to permanently map as much physical memory as
972 If the machine has between 1 and 4 Gigabytes physical RAM, then
975 If more than 4 Gigabytes is used then answer "64GB" here. This
976 selection turns Intel PAE (Physical Address Extension) mode on.
977 PAE implements 3-level paging on IA32 processors. PAE is fully
978 supported by Linux, PAE mode is implemented on all recent Intel
979 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
980 then the kernel will not boot on CPUs that don't support PAE!
982 The actual amount of total physical memory will either be
983 auto detected or can be forced by using a kernel command line option
984 such as "mem=256M". (Try "man bootparam" or see the documentation of
985 your boot loader (lilo or loadlin) about how to pass options to the
986 kernel at boot time.)
988 If unsure, say "off".
992 depends on !X86_NUMAQ
994 Select this if you have a 32-bit processor and between 1 and 4
995 gigabytes of physical RAM.
999 depends on !M386 && !M486
1002 Select this if you have a 32-bit processor and more than 4
1003 gigabytes of physical RAM.
1008 depends on EXPERIMENTAL
1009 prompt "Memory split" if EMBEDDED
1013 Select the desired split between kernel and user memory.
1015 If the address range available to the kernel is less than the
1016 physical memory installed, the remaining memory will be available
1017 as "high memory". Accessing high memory is a little more costly
1018 than low memory, as it needs to be mapped into the kernel first.
1019 Note that increasing the kernel address space limits the range
1020 available to user programs, making the address space there
1021 tighter. Selecting anything other than the default 3G/1G split
1022 will also likely make your kernel incompatible with binary-only
1025 If you are not absolutely sure what you are doing, leave this
1029 bool "3G/1G user/kernel split"
1030 config VMSPLIT_3G_OPT
1032 bool "3G/1G user/kernel split (for full 1G low memory)"
1034 bool "2G/2G user/kernel split"
1035 config VMSPLIT_2G_OPT
1037 bool "2G/2G user/kernel split (for full 2G low memory)"
1039 bool "1G/3G user/kernel split"
1044 default 0xB0000000 if VMSPLIT_3G_OPT
1045 default 0x80000000 if VMSPLIT_2G
1046 default 0x78000000 if VMSPLIT_2G_OPT
1047 default 0x40000000 if VMSPLIT_1G
1053 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1056 bool "PAE (Physical Address Extension) Support"
1057 depends on X86_32 && !HIGHMEM4G
1059 PAE is required for NX support, and furthermore enables
1060 larger swapspace support for non-overcommit purposes. It
1061 has the cost of more pagetable lookup overhead, and also
1062 consumes more pagetable space per process.
1064 config ARCH_PHYS_ADDR_T_64BIT
1065 def_bool X86_64 || X86_PAE
1067 config DIRECT_GBPAGES
1068 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1072 Allow the kernel linear mapping to use 1GB pages on CPUs that
1073 support it. This can improve the kernel's performance a tiny bit by
1074 reducing TLB pressure. If in doubt, say "Y".
1076 # Common NUMA Features
1078 bool "Numa Memory Allocation and Scheduler Support"
1080 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1081 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1083 Enable NUMA (Non Uniform Memory Access) support.
1085 The kernel will try to allocate memory used by a CPU on the
1086 local memory controller of the CPU and add some more
1087 NUMA awareness to the kernel.
1089 For 64-bit this is recommended if the system is Intel Core i7
1090 (or later), AMD Opteron, or EM64T NUMA.
1092 For 32-bit this is only needed on (rare) 32-bit-only platforms
1093 that support NUMA topologies, such as NUMAQ / Summit, or if you
1094 boot a 32-bit kernel on a 64-bit NUMA platform.
1096 Otherwise, you should say N.
1098 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1099 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1103 prompt "Old style AMD Opteron NUMA detection"
1104 depends on X86_64 && NUMA && PCI
1106 Enable K8 NUMA node topology detection. You should say Y here if
1107 you have a multi processor AMD K8 system. This uses an old
1108 method to read the NUMA configuration directly from the builtin
1109 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1110 instead, which also takes priority if both are compiled in.
1112 config X86_64_ACPI_NUMA
1114 prompt "ACPI NUMA detection"
1115 depends on X86_64 && NUMA && ACPI && PCI
1118 Enable ACPI SRAT based node topology detection.
1120 # Some NUMA nodes have memory ranges that span
1121 # other nodes. Even though a pfn is valid and
1122 # between a node's start and end pfns, it may not
1123 # reside on that node. See memmap_init_zone()
1125 config NODES_SPAN_OTHER_NODES
1127 depends on X86_64_ACPI_NUMA
1130 bool "NUMA emulation"
1131 depends on X86_64 && NUMA
1133 Enable NUMA emulation. A flat machine will be split
1134 into virtual nodes when booted with "numa=fake=N", where N is the
1135 number of nodes. This is only useful for debugging.
1138 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1140 default "9" if MAXSMP
1141 default "6" if X86_64
1142 default "4" if X86_NUMAQ
1144 depends on NEED_MULTIPLE_NODES
1146 Specify the maximum number of NUMA Nodes available on the target
1147 system. Increases memory reserved to accommodate various tables.
1149 config HAVE_ARCH_BOOTMEM
1151 depends on X86_32 && NUMA
1153 config ARCH_HAVE_MEMORY_PRESENT
1155 depends on X86_32 && DISCONTIGMEM
1157 config NEED_NODE_MEMMAP_SIZE
1159 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1161 config HAVE_ARCH_ALLOC_REMAP
1163 depends on X86_32 && NUMA
1165 config ARCH_FLATMEM_ENABLE
1167 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1169 config ARCH_DISCONTIGMEM_ENABLE
1171 depends on NUMA && X86_32
1173 config ARCH_DISCONTIGMEM_DEFAULT
1175 depends on NUMA && X86_32
1177 config ARCH_SPARSEMEM_DEFAULT
1181 config ARCH_SPARSEMEM_ENABLE
1183 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1184 select SPARSEMEM_STATIC if X86_32
1185 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1187 config ARCH_SELECT_MEMORY_MODEL
1189 depends on ARCH_SPARSEMEM_ENABLE
1191 config ARCH_MEMORY_PROBE
1193 depends on MEMORY_HOTPLUG
1198 bool "Allocate 3rd-level pagetables from highmem"
1199 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1201 The VM uses one page table entry for each page of physical memory.
1202 For systems with a lot of RAM, this can be wasteful of precious
1203 low memory. Setting this option will put user-space page table
1204 entries in high memory.
1206 config X86_CHECK_BIOS_CORRUPTION
1207 bool "Check for low memory corruption"
1209 Periodically check for memory corruption in low memory, which
1210 is suspected to be caused by BIOS. Even when enabled in the
1211 configuration, it is disabled at runtime. Enable it by
1212 setting "memory_corruption_check=1" on the kernel command
1213 line. By default it scans the low 64k of memory every 60
1214 seconds; see the memory_corruption_check_size and
1215 memory_corruption_check_period parameters in
1216 Documentation/kernel-parameters.txt to adjust this.
1218 When enabled with the default parameters, this option has
1219 almost no overhead, as it reserves a relatively small amount
1220 of memory and scans it infrequently. It both detects corruption
1221 and prevents it from affecting the running system.
1223 It is, however, intended as a diagnostic tool; if repeatable
1224 BIOS-originated corruption always affects the same memory,
1225 you can use memmap= to prevent the kernel from using that
1228 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1229 bool "Set the default setting of memory_corruption_check"
1230 depends on X86_CHECK_BIOS_CORRUPTION
1233 Set whether the default state of memory_corruption_check is
1236 config X86_RESERVE_LOW_64K
1237 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1240 Reserve the first 64K of physical RAM on BIOSes that are known
1241 to potentially corrupt that memory range. A numbers of BIOSes are
1242 known to utilize this area during suspend/resume, so it must not
1243 be used by the kernel.
1245 Set this to N if you are absolutely sure that you trust the BIOS
1246 to get all its memory reservations and usages right.
1248 If you have doubts about the BIOS (e.g. suspend/resume does not
1249 work or there's kernel crashes after certain hardware hotplug
1250 events) and it's not AMI or Phoenix, then you might want to enable
1251 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1252 corruption patterns.
1256 config MATH_EMULATION
1258 prompt "Math emulation" if X86_32
1260 Linux can emulate a math coprocessor (used for floating point
1261 operations) if you don't have one. 486DX and Pentium processors have
1262 a math coprocessor built in, 486SX and 386 do not, unless you added
1263 a 487DX or 387, respectively. (The messages during boot time can
1264 give you some hints here ["man dmesg"].) Everyone needs either a
1265 coprocessor or this emulation.
1267 If you don't have a math coprocessor, you need to say Y here; if you
1268 say Y here even though you have a coprocessor, the coprocessor will
1269 be used nevertheless. (This behavior can be changed with the kernel
1270 command line option "no387", which comes handy if your coprocessor
1271 is broken. Try "man bootparam" or see the documentation of your boot
1272 loader (lilo or loadlin) about how to pass options to the kernel at
1273 boot time.) This means that it is a good idea to say Y here if you
1274 intend to use this kernel on different machines.
1276 More information about the internals of the Linux math coprocessor
1277 emulation can be found in <file:arch/x86/math-emu/README>.
1279 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1280 kernel, it won't hurt.
1283 bool "MTRR (Memory Type Range Register) support"
1285 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1286 the Memory Type Range Registers (MTRRs) may be used to control
1287 processor access to memory ranges. This is most useful if you have
1288 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1289 allows bus write transfers to be combined into a larger transfer
1290 before bursting over the PCI/AGP bus. This can increase performance
1291 of image write operations 2.5 times or more. Saying Y here creates a
1292 /proc/mtrr file which may be used to manipulate your processor's
1293 MTRRs. Typically the X server should use this.
1295 This code has a reasonably generic interface so that similar
1296 control registers on other processors can be easily supported
1299 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1300 Registers (ARRs) which provide a similar functionality to MTRRs. For
1301 these, the ARRs are used to emulate the MTRRs.
1302 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1303 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1304 write-combining. All of these processors are supported by this code
1305 and it makes sense to say Y here if you have one of them.
1307 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1308 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1309 can lead to all sorts of problems, so it's good to say Y here.
1311 You can safely say Y even if your machine doesn't have MTRRs, you'll
1312 just add about 9 KB to your kernel.
1314 See <file:Documentation/x86/mtrr.txt> for more information.
1316 config MTRR_SANITIZER
1318 prompt "MTRR cleanup support"
1321 Convert MTRR layout from continuous to discrete, so X drivers can
1322 add writeback entries.
1324 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1325 The largest mtrr entry size for a continuous block can be set with
1330 config MTRR_SANITIZER_ENABLE_DEFAULT
1331 int "MTRR cleanup enable value (0-1)"
1334 depends on MTRR_SANITIZER
1336 Enable mtrr cleanup default value
1338 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1339 int "MTRR cleanup spare reg num (0-7)"
1342 depends on MTRR_SANITIZER
1344 mtrr cleanup spare entries default, it can be changed via
1345 mtrr_spare_reg_nr=N on the kernel command line.
1349 prompt "x86 PAT support"
1352 Use PAT attributes to setup page level cache control.
1354 PATs are the modern equivalents of MTRRs and are much more
1355 flexible than MTRRs.
1357 Say N here if you see bootup problems (boot crash, boot hang,
1358 spontaneous reboots) or a non-working video driver.
1363 bool "EFI runtime service support"
1366 This enables the kernel to use EFI runtime services that are
1367 available (such as the EFI variable services).
1369 This option is only useful on systems that have EFI firmware.
1370 In addition, you should use the latest ELILO loader available
1371 at <http://elilo.sourceforge.net> in order to take advantage
1372 of EFI runtime services. However, even with this option, the
1373 resultant kernel should continue to boot on existing non-EFI
1378 prompt "Enable seccomp to safely compute untrusted bytecode"
1380 This kernel feature is useful for number crunching applications
1381 that may need to compute untrusted bytecode during their
1382 execution. By using pipes or other transports made available to
1383 the process as file descriptors supporting the read/write
1384 syscalls, it's possible to isolate those applications in
1385 their own address space using seccomp. Once seccomp is
1386 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1387 and the task is only allowed to execute a few safe syscalls
1388 defined by each seccomp mode.
1390 If unsure, say Y. Only embedded should say N here.
1392 config CC_STACKPROTECTOR_ALL
1395 config CC_STACKPROTECTOR
1396 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1397 select CC_STACKPROTECTOR_ALL
1399 This option turns on the -fstack-protector GCC feature. This
1400 feature puts, at the beginning of functions, a canary value on
1401 the stack just before the return address, and validates
1402 the value just before actually returning. Stack based buffer
1403 overflows (that need to overwrite this return address) now also
1404 overwrite the canary, which gets detected and the attack is then
1405 neutralized via a kernel panic.
1407 This feature requires gcc version 4.2 or above, or a distribution
1408 gcc with the feature backported. Older versions are automatically
1409 detected and for those versions, this configuration option is
1410 ignored. (and a warning is printed during bootup)
1412 source kernel/Kconfig.hz
1415 bool "kexec system call"
1417 kexec is a system call that implements the ability to shutdown your
1418 current kernel, and to start another kernel. It is like a reboot
1419 but it is independent of the system firmware. And like a reboot
1420 you can start any kernel with it, not just Linux.
1422 The name comes from the similarity to the exec system call.
1424 It is an ongoing process to be certain the hardware in a machine
1425 is properly shutdown, so do not be surprised if this code does not
1426 initially work for you. It may help to enable device hotplugging
1427 support. As of this writing the exact hardware interface is
1428 strongly in flux, so no good recommendation can be made.
1431 bool "kernel crash dumps"
1432 depends on X86_64 || (X86_32 && HIGHMEM)
1434 Generate crash dump after being started by kexec.
1435 This should be normally only set in special crash dump kernels
1436 which are loaded in the main kernel with kexec-tools into
1437 a specially reserved region and then later executed after
1438 a crash by kdump/kexec. The crash dump kernel must be compiled
1439 to a memory address not used by the main kernel or BIOS using
1440 PHYSICAL_START, or it must be built as a relocatable image
1441 (CONFIG_RELOCATABLE=y).
1442 For more details see Documentation/kdump/kdump.txt
1445 bool "kexec jump (EXPERIMENTAL)"
1446 depends on EXPERIMENTAL
1447 depends on KEXEC && HIBERNATION
1449 Jump between original kernel and kexeced kernel and invoke
1450 code in physical address mode via KEXEC
1452 config PHYSICAL_START
1453 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1454 default "0x1000000" if X86_NUMAQ
1455 default "0x200000" if X86_64
1458 This gives the physical address where the kernel is loaded.
1460 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1461 bzImage will decompress itself to above physical address and
1462 run from there. Otherwise, bzImage will run from the address where
1463 it has been loaded by the boot loader and will ignore above physical
1466 In normal kdump cases one does not have to set/change this option
1467 as now bzImage can be compiled as a completely relocatable image
1468 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1469 address. This option is mainly useful for the folks who don't want
1470 to use a bzImage for capturing the crash dump and want to use a
1471 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1472 to be specifically compiled to run from a specific memory area
1473 (normally a reserved region) and this option comes handy.
1475 So if you are using bzImage for capturing the crash dump, leave
1476 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1477 Otherwise if you plan to use vmlinux for capturing the crash dump
1478 change this value to start of the reserved region (Typically 16MB
1479 0x1000000). In other words, it can be set based on the "X" value as
1480 specified in the "crashkernel=YM@XM" command line boot parameter
1481 passed to the panic-ed kernel. Typically this parameter is set as
1482 crashkernel=64M@16M. Please take a look at
1483 Documentation/kdump/kdump.txt for more details about crash dumps.
1485 Usage of bzImage for capturing the crash dump is recommended as
1486 one does not have to build two kernels. Same kernel can be used
1487 as production kernel and capture kernel. Above option should have
1488 gone away after relocatable bzImage support is introduced. But it
1489 is present because there are users out there who continue to use
1490 vmlinux for dump capture. This option should go away down the
1493 Don't change this unless you know what you are doing.
1496 bool "Build a relocatable kernel (EXPERIMENTAL)"
1497 depends on EXPERIMENTAL
1499 This builds a kernel image that retains relocation information
1500 so it can be loaded someplace besides the default 1MB.
1501 The relocations tend to make the kernel binary about 10% larger,
1502 but are discarded at runtime.
1504 One use is for the kexec on panic case where the recovery kernel
1505 must live at a different physical address than the primary
1508 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1509 it has been loaded at and the compile time physical address
1510 (CONFIG_PHYSICAL_START) is ignored.
1512 config PHYSICAL_ALIGN
1514 prompt "Alignment value to which kernel should be aligned" if X86_32
1515 default "0x100000" if X86_32
1516 default "0x200000" if X86_64
1517 range 0x2000 0x400000
1519 This value puts the alignment restrictions on physical address
1520 where kernel is loaded and run from. Kernel is compiled for an
1521 address which meets above alignment restriction.
1523 If bootloader loads the kernel at a non-aligned address and
1524 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1525 address aligned to above value and run from there.
1527 If bootloader loads the kernel at a non-aligned address and
1528 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1529 load address and decompress itself to the address it has been
1530 compiled for and run from there. The address for which kernel is
1531 compiled already meets above alignment restrictions. Hence the
1532 end result is that kernel runs from a physical address meeting
1533 above alignment restrictions.
1535 Don't change this unless you know what you are doing.
1538 bool "Support for hot-pluggable CPUs"
1539 depends on SMP && HOTPLUG
1541 Say Y here to allow turning CPUs off and on. CPUs can be
1542 controlled through /sys/devices/system/cpu.
1543 ( Note: power management support will enable this option
1544 automatically on SMP systems. )
1545 Say N if you want to disable CPU hotplug.
1549 prompt "Compat VDSO support"
1550 depends on X86_32 || IA32_EMULATION
1552 Map the 32-bit VDSO to the predictable old-style address too.
1554 Say N here if you are running a sufficiently recent glibc
1555 version (2.3.3 or later), to remove the high-mapped
1556 VDSO mapping and to exclusively use the randomized VDSO.
1561 bool "Built-in kernel command line"
1564 Allow for specifying boot arguments to the kernel at
1565 build time. On some systems (e.g. embedded ones), it is
1566 necessary or convenient to provide some or all of the
1567 kernel boot arguments with the kernel itself (that is,
1568 to not rely on the boot loader to provide them.)
1570 To compile command line arguments into the kernel,
1571 set this option to 'Y', then fill in the
1572 the boot arguments in CONFIG_CMDLINE.
1574 Systems with fully functional boot loaders (i.e. non-embedded)
1575 should leave this option set to 'N'.
1578 string "Built-in kernel command string"
1579 depends on CMDLINE_BOOL
1582 Enter arguments here that should be compiled into the kernel
1583 image and used at boot time. If the boot loader provides a
1584 command line at boot time, it is appended to this string to
1585 form the full kernel command line, when the system boots.
1587 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1588 change this behavior.
1590 In most cases, the command line (whether built-in or provided
1591 by the boot loader) should specify the device for the root
1594 config CMDLINE_OVERRIDE
1595 bool "Built-in command line overrides boot loader arguments"
1597 depends on CMDLINE_BOOL
1599 Set this option to 'Y' to have the kernel ignore the boot loader
1600 command line, and use ONLY the built-in command line.
1602 This is used to work around broken boot loaders. This should
1603 be set to 'N' under normal conditions.
1607 config ARCH_ENABLE_MEMORY_HOTPLUG
1609 depends on X86_64 || (X86_32 && HIGHMEM)
1611 config ARCH_ENABLE_MEMORY_HOTREMOVE
1613 depends on MEMORY_HOTPLUG
1615 config HAVE_ARCH_EARLY_PFN_TO_NID
1619 menu "Power management and ACPI options"
1621 config ARCH_HIBERNATION_HEADER
1623 depends on X86_64 && HIBERNATION
1625 source "kernel/power/Kconfig"
1627 source "drivers/acpi/Kconfig"
1632 depends on APM || APM_MODULE
1635 tristate "APM (Advanced Power Management) BIOS support"
1636 depends on X86_32 && PM_SLEEP
1638 APM is a BIOS specification for saving power using several different
1639 techniques. This is mostly useful for battery powered laptops with
1640 APM compliant BIOSes. If you say Y here, the system time will be
1641 reset after a RESUME operation, the /proc/apm device will provide
1642 battery status information, and user-space programs will receive
1643 notification of APM "events" (e.g. battery status change).
1645 If you select "Y" here, you can disable actual use of the APM
1646 BIOS by passing the "apm=off" option to the kernel at boot time.
1648 Note that the APM support is almost completely disabled for
1649 machines with more than one CPU.
1651 In order to use APM, you will need supporting software. For location
1652 and more information, read <file:Documentation/power/pm.txt> and the
1653 Battery Powered Linux mini-HOWTO, available from
1654 <http://www.tldp.org/docs.html#howto>.
1656 This driver does not spin down disk drives (see the hdparm(8)
1657 manpage ("man 8 hdparm") for that), and it doesn't turn off
1658 VESA-compliant "green" monitors.
1660 This driver does not support the TI 4000M TravelMate and the ACER
1661 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1662 desktop machines also don't have compliant BIOSes, and this driver
1663 may cause those machines to panic during the boot phase.
1665 Generally, if you don't have a battery in your machine, there isn't
1666 much point in using this driver and you should say N. If you get
1667 random kernel OOPSes or reboots that don't seem to be related to
1668 anything, try disabling/enabling this option (or disabling/enabling
1671 Some other things you should try when experiencing seemingly random,
1674 1) make sure that you have enough swap space and that it is
1676 2) pass the "no-hlt" option to the kernel
1677 3) switch on floating point emulation in the kernel and pass
1678 the "no387" option to the kernel
1679 4) pass the "floppy=nodma" option to the kernel
1680 5) pass the "mem=4M" option to the kernel (thereby disabling
1681 all but the first 4 MB of RAM)
1682 6) make sure that the CPU is not over clocked.
1683 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1684 8) disable the cache from your BIOS settings
1685 9) install a fan for the video card or exchange video RAM
1686 10) install a better fan for the CPU
1687 11) exchange RAM chips
1688 12) exchange the motherboard.
1690 To compile this driver as a module, choose M here: the
1691 module will be called apm.
1695 config APM_IGNORE_USER_SUSPEND
1696 bool "Ignore USER SUSPEND"
1698 This option will ignore USER SUSPEND requests. On machines with a
1699 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1700 series notebooks, it is necessary to say Y because of a BIOS bug.
1702 config APM_DO_ENABLE
1703 bool "Enable PM at boot time"
1705 Enable APM features at boot time. From page 36 of the APM BIOS
1706 specification: "When disabled, the APM BIOS does not automatically
1707 power manage devices, enter the Standby State, enter the Suspend
1708 State, or take power saving steps in response to CPU Idle calls."
1709 This driver will make CPU Idle calls when Linux is idle (unless this
1710 feature is turned off -- see "Do CPU IDLE calls", below). This
1711 should always save battery power, but more complicated APM features
1712 will be dependent on your BIOS implementation. You may need to turn
1713 this option off if your computer hangs at boot time when using APM
1714 support, or if it beeps continuously instead of suspending. Turn
1715 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1716 T400CDT. This is off by default since most machines do fine without
1720 bool "Make CPU Idle calls when idle"
1722 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1723 On some machines, this can activate improved power savings, such as
1724 a slowed CPU clock rate, when the machine is idle. These idle calls
1725 are made after the idle loop has run for some length of time (e.g.,
1726 333 mS). On some machines, this will cause a hang at boot time or
1727 whenever the CPU becomes idle. (On machines with more than one CPU,
1728 this option does nothing.)
1730 config APM_DISPLAY_BLANK
1731 bool "Enable console blanking using APM"
1733 Enable console blanking using the APM. Some laptops can use this to
1734 turn off the LCD backlight when the screen blanker of the Linux
1735 virtual console blanks the screen. Note that this is only used by
1736 the virtual console screen blanker, and won't turn off the backlight
1737 when using the X Window system. This also doesn't have anything to
1738 do with your VESA-compliant power-saving monitor. Further, this
1739 option doesn't work for all laptops -- it might not turn off your
1740 backlight at all, or it might print a lot of errors to the console,
1741 especially if you are using gpm.
1743 config APM_ALLOW_INTS
1744 bool "Allow interrupts during APM BIOS calls"
1746 Normally we disable external interrupts while we are making calls to
1747 the APM BIOS as a measure to lessen the effects of a badly behaving
1748 BIOS implementation. The BIOS should reenable interrupts if it
1749 needs to. Unfortunately, some BIOSes do not -- especially those in
1750 many of the newer IBM Thinkpads. If you experience hangs when you
1751 suspend, try setting this to Y. Otherwise, say N.
1755 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1757 source "drivers/cpuidle/Kconfig"
1759 source "drivers/idle/Kconfig"
1764 menu "Bus options (PCI etc.)"
1769 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1771 Find out whether you have a PCI motherboard. PCI is the name of a
1772 bus system, i.e. the way the CPU talks to the other stuff inside
1773 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1774 VESA. If you have PCI, say Y, otherwise N.
1777 prompt "PCI access mode"
1778 depends on X86_32 && PCI
1781 On PCI systems, the BIOS can be used to detect the PCI devices and
1782 determine their configuration. However, some old PCI motherboards
1783 have BIOS bugs and may crash if this is done. Also, some embedded
1784 PCI-based systems don't have any BIOS at all. Linux can also try to
1785 detect the PCI hardware directly without using the BIOS.
1787 With this option, you can specify how Linux should detect the
1788 PCI devices. If you choose "BIOS", the BIOS will be used,
1789 if you choose "Direct", the BIOS won't be used, and if you
1790 choose "MMConfig", then PCI Express MMCONFIG will be used.
1791 If you choose "Any", the kernel will try MMCONFIG, then the
1792 direct access method and falls back to the BIOS if that doesn't
1793 work. If unsure, go with the default, which is "Any".
1798 config PCI_GOMMCONFIG
1815 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1817 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1820 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1824 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1828 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1835 bool "Support mmconfig PCI config space access"
1836 depends on X86_64 && PCI && ACPI
1839 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1840 depends on PCI_MSI && ACPI && EXPERIMENTAL
1842 DMA remapping (DMAR) devices support enables independent address
1843 translations for Direct Memory Access (DMA) from devices.
1844 These DMA remapping devices are reported via ACPI tables
1845 and include PCI device scope covered by these DMA
1848 config DMAR_DEFAULT_ON
1850 prompt "Enable DMA Remapping Devices by default"
1853 Selecting this option will enable a DMAR device at boot time if
1854 one is found. If this option is not selected, DMAR support can
1855 be enabled by passing intel_iommu=on to the kernel. It is
1856 recommended you say N here while the DMAR code remains
1861 prompt "Support for Graphics workaround"
1864 Current Graphics drivers tend to use physical address
1865 for DMA and avoid using DMA APIs. Setting this config
1866 option permits the IOMMU driver to set a unity map for
1867 all the OS-visible memory. Hence the driver can continue
1868 to use physical addresses for DMA.
1870 config DMAR_FLOPPY_WA
1874 Floppy disk drivers are know to bypass DMA API calls
1875 thereby failing to work when IOMMU is enabled. This
1876 workaround will setup a 1:1 mapping for the first
1877 16M to make floppy (an ISA device) work.
1880 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1881 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1883 Supports Interrupt remapping for IO-APIC and MSI devices.
1884 To use x2apic mode in the CPU's which support x2APIC enhancements or
1885 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1887 source "drivers/pci/pcie/Kconfig"
1889 source "drivers/pci/Kconfig"
1891 # x86_64 have no ISA slots, but do have ISA-style DMA.
1900 Find out whether you have ISA slots on your motherboard. ISA is the
1901 name of a bus system, i.e. the way the CPU talks to the other stuff
1902 inside your box. Other bus systems are PCI, EISA, MicroChannel
1903 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1904 newer boards don't support it. If you have ISA, say Y, otherwise N.
1910 The Extended Industry Standard Architecture (EISA) bus was
1911 developed as an open alternative to the IBM MicroChannel bus.
1913 The EISA bus provided some of the features of the IBM MicroChannel
1914 bus while maintaining backward compatibility with cards made for
1915 the older ISA bus. The EISA bus saw limited use between 1988 and
1916 1995 when it was made obsolete by the PCI bus.
1918 Say Y here if you are building a kernel for an EISA-based machine.
1922 source "drivers/eisa/Kconfig"
1927 MicroChannel Architecture is found in some IBM PS/2 machines and
1928 laptops. It is a bus system similar to PCI or ISA. See
1929 <file:Documentation/mca.txt> (and especially the web page given
1930 there) before attempting to build an MCA bus kernel.
1932 source "drivers/mca/Kconfig"
1935 tristate "NatSemi SCx200 support"
1937 This provides basic support for National Semiconductor's
1938 (now AMD's) Geode processors. The driver probes for the
1939 PCI-IDs of several on-chip devices, so its a good dependency
1940 for other scx200_* drivers.
1942 If compiled as a module, the driver is named scx200.
1944 config SCx200HR_TIMER
1945 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1946 depends on SCx200 && GENERIC_TIME
1949 This driver provides a clocksource built upon the on-chip
1950 27MHz high-resolution timer. Its also a workaround for
1951 NSC Geode SC-1100's buggy TSC, which loses time when the
1952 processor goes idle (as is done by the scheduler). The
1953 other workaround is idle=poll boot option.
1955 config GEODE_MFGPT_TIMER
1957 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1958 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1960 This driver provides a clock event source based on the MFGPT
1961 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1962 MFGPTs have a better resolution and max interval than the
1963 generic PIT, and are suitable for use as high-res timers.
1966 bool "One Laptop Per Child support"
1969 Add support for detecting the unique features of the OLPC
1976 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1978 source "drivers/pcmcia/Kconfig"
1980 source "drivers/pci/hotplug/Kconfig"
1985 menu "Executable file formats / Emulations"
1987 source "fs/Kconfig.binfmt"
1989 config IA32_EMULATION
1990 bool "IA32 Emulation"
1992 select COMPAT_BINFMT_ELF
1994 Include code to run 32-bit programs under a 64-bit kernel. You should
1995 likely turn this on, unless you're 100% sure that you don't have any
1996 32-bit programs left.
1999 tristate "IA32 a.out support"
2000 depends on IA32_EMULATION
2002 Support old a.out binaries in the 32bit emulation.
2006 depends on IA32_EMULATION
2008 config COMPAT_FOR_U64_ALIGNMENT
2012 config SYSVIPC_COMPAT
2014 depends on COMPAT && SYSVIPC
2019 config HAVE_ATOMIC_IOMAP
2023 source "net/Kconfig"
2025 source "drivers/Kconfig"
2027 source "drivers/firmware/Kconfig"
2031 source "arch/x86/Kconfig.debug"
2033 source "security/Kconfig"
2035 source "crypto/Kconfig"
2037 source "arch/x86/kvm/Kconfig"
2039 source "lib/Kconfig"
projects / linux-2.6 / blob