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 8 if SMP && X86_32 && !X86_BIGSMP
668 range 2 512 if SMP && !MAXSMP
670 default "4096" if MAXSMP
671 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
674 This allows you to specify the maximum number of CPUs which this
675 kernel will support. The maximum supported value is 512 and the
676 minimum value which makes sense is 2.
678 This is purely to save memory - each supported CPU adds
679 approximately eight kilobytes to the kernel image.
682 bool "SMT (Hyperthreading) scheduler support"
685 SMT scheduler support improves the CPU scheduler's decision making
686 when dealing with Intel Pentium 4 chips with HyperThreading at a
687 cost of slightly increased overhead in some places. If unsure say
692 prompt "Multi-core scheduler support"
695 Multi-core scheduler support improves the CPU scheduler's decision
696 making when dealing with multi-core CPU chips at a cost of slightly
697 increased overhead in some places. If unsure say N here.
699 source "kernel/Kconfig.preempt"
702 bool "Local APIC support on uniprocessors"
703 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
705 A local APIC (Advanced Programmable Interrupt Controller) is an
706 integrated interrupt controller in the CPU. If you have a single-CPU
707 system which has a processor with a local APIC, you can say Y here to
708 enable and use it. If you say Y here even though your machine doesn't
709 have a local APIC, then the kernel will still run with no slowdown at
710 all. The local APIC supports CPU-generated self-interrupts (timer,
711 performance counters), and the NMI watchdog which detects hard
715 bool "IO-APIC support on uniprocessors"
716 depends on X86_UP_APIC
718 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
719 SMP-capable replacement for PC-style interrupt controllers. Most
720 SMP systems and many recent uniprocessor systems have one.
722 If you have a single-CPU system with an IO-APIC, you can say Y here
723 to use it. If you say Y here even though your machine doesn't have
724 an IO-APIC, then the kernel will still run with no slowdown at all.
726 config X86_LOCAL_APIC
728 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
732 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
734 config X86_VISWS_APIC
736 depends on X86_32 && X86_VISWS
738 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
739 bool "Reroute for broken boot IRQs"
741 depends on X86_IO_APIC
743 This option enables a workaround that fixes a source of
744 spurious interrupts. This is recommended when threaded
745 interrupt handling is used on systems where the generation of
746 superfluous "boot interrupts" cannot be disabled.
748 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
749 entry in the chipset's IO-APIC is masked (as, e.g. the RT
750 kernel does during interrupt handling). On chipsets where this
751 boot IRQ generation cannot be disabled, this workaround keeps
752 the original IRQ line masked so that only the equivalent "boot
753 IRQ" is delivered to the CPUs. The workaround also tells the
754 kernel to set up the IRQ handler on the boot IRQ line. In this
755 way only one interrupt is delivered to the kernel. Otherwise
756 the spurious second interrupt may cause the kernel to bring
757 down (vital) interrupt lines.
759 Only affects "broken" chipsets. Interrupt sharing may be
760 increased on these systems.
763 bool "Machine Check Exception"
765 Machine Check Exception support allows the processor to notify the
766 kernel if it detects a problem (e.g. overheating, component failure).
767 The action the kernel takes depends on the severity of the problem,
768 ranging from a warning message on the console, to halting the machine.
769 Your processor must be a Pentium or newer to support this - check the
770 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
771 have a design flaw which leads to false MCE events - hence MCE is
772 disabled on all P5 processors, unless explicitly enabled with "mce"
773 as a boot argument. Similarly, if MCE is built in and creates a
774 problem on some new non-standard machine, you can boot with "nomce"
775 to disable it. MCE support simply ignores non-MCE processors like
776 the 386 and 486, so nearly everyone can say Y here.
780 prompt "Intel MCE features"
781 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
783 Additional support for intel specific MCE features such as
788 prompt "AMD MCE features"
789 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
791 Additional support for AMD specific MCE features such as
792 the DRAM Error Threshold.
794 config X86_MCE_THRESHOLD
795 depends on X86_MCE_AMD || X86_MCE_INTEL
799 config X86_MCE_NONFATAL
800 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
801 depends on X86_32 && X86_MCE
803 Enabling this feature starts a timer that triggers every 5 seconds which
804 will look at the machine check registers to see if anything happened.
805 Non-fatal problems automatically get corrected (but still logged).
806 Disable this if you don't want to see these messages.
807 Seeing the messages this option prints out may be indicative of dying
808 or out-of-spec (ie, overclocked) hardware.
809 This option only does something on certain CPUs.
810 (AMD Athlon/Duron and Intel Pentium 4)
812 config X86_MCE_P4THERMAL
813 bool "check for P4 thermal throttling interrupt."
814 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
816 Enabling this feature will cause a message to be printed when the P4
817 enters thermal throttling.
820 bool "Enable VM86 support" if EMBEDDED
824 This option is required by programs like DOSEMU to run 16-bit legacy
825 code on X86 processors. It also may be needed by software like
826 XFree86 to initialize some video cards via BIOS. Disabling this
827 option saves about 6k.
830 tristate "Toshiba Laptop support"
833 This adds a driver to safely access the System Management Mode of
834 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
835 not work on models with a Phoenix BIOS. The System Management Mode
836 is used to set the BIOS and power saving options on Toshiba portables.
838 For information on utilities to make use of this driver see the
839 Toshiba Linux utilities web site at:
840 <http://www.buzzard.org.uk/toshiba/>.
842 Say Y if you intend to run this kernel on a Toshiba portable.
846 tristate "Dell laptop support"
848 This adds a driver to safely access the System Management Mode
849 of the CPU on the Dell Inspiron 8000. The System Management Mode
850 is used to read cpu temperature and cooling fan status and to
851 control the fans on the I8K portables.
853 This driver has been tested only on the Inspiron 8000 but it may
854 also work with other Dell laptops. You can force loading on other
855 models by passing the parameter `force=1' to the module. Use at
858 For information on utilities to make use of this driver see the
859 I8K Linux utilities web site at:
860 <http://people.debian.org/~dz/i8k/>
862 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
865 config X86_REBOOTFIXUPS
866 bool "Enable X86 board specific fixups for reboot"
869 This enables chipset and/or board specific fixups to be done
870 in order to get reboot to work correctly. This is only needed on
871 some combinations of hardware and BIOS. The symptom, for which
872 this config is intended, is when reboot ends with a stalled/hung
875 Currently, the only fixup is for the Geode machines using
876 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
878 Say Y if you want to enable the fixup. Currently, it's safe to
879 enable this option even if you don't need it.
883 tristate "/dev/cpu/microcode - microcode support"
886 If you say Y here, you will be able to update the microcode on
887 certain Intel and AMD processors. The Intel support is for the
888 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
889 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
890 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
891 You will obviously need the actual microcode binary data itself
892 which is not shipped with the Linux kernel.
894 This option selects the general module only, you need to select
895 at least one vendor specific module as well.
897 To compile this driver as a module, choose M here: the
898 module will be called microcode.
900 config MICROCODE_INTEL
901 bool "Intel microcode patch loading support"
906 This options enables microcode patch loading support for Intel
909 For latest news and information on obtaining all the required
910 Intel ingredients for this driver, check:
911 <http://www.urbanmyth.org/microcode/>.
914 bool "AMD microcode patch loading support"
918 If you select this option, microcode patch loading support for AMD
919 processors will be enabled.
921 config MICROCODE_OLD_INTERFACE
926 tristate "/dev/cpu/*/msr - Model-specific register support"
928 This device gives privileged processes access to the x86
929 Model-Specific Registers (MSRs). It is a character device with
930 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
931 MSR accesses are directed to a specific CPU on multi-processor
935 tristate "/dev/cpu/*/cpuid - CPU information support"
937 This device gives processes access to the x86 CPUID instruction to
938 be executed on a specific processor. It is a character device
939 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
943 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
945 If you select this option, this will provide various x86 CPUs
946 information through debugfs.
949 prompt "High Memory Support"
950 default HIGHMEM4G if !X86_NUMAQ
951 default HIGHMEM64G if X86_NUMAQ
956 depends on !X86_NUMAQ
958 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
959 However, the address space of 32-bit x86 processors is only 4
960 Gigabytes large. That means that, if you have a large amount of
961 physical memory, not all of it can be "permanently mapped" by the
962 kernel. The physical memory that's not permanently mapped is called
965 If you are compiling a kernel which will never run on a machine with
966 more than 1 Gigabyte total physical RAM, answer "off" here (default
967 choice and suitable for most users). This will result in a "3GB/1GB"
968 split: 3GB are mapped so that each process sees a 3GB virtual memory
969 space and the remaining part of the 4GB virtual memory space is used
970 by the kernel to permanently map as much physical memory as
973 If the machine has between 1 and 4 Gigabytes physical RAM, then
976 If more than 4 Gigabytes is used then answer "64GB" here. This
977 selection turns Intel PAE (Physical Address Extension) mode on.
978 PAE implements 3-level paging on IA32 processors. PAE is fully
979 supported by Linux, PAE mode is implemented on all recent Intel
980 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
981 then the kernel will not boot on CPUs that don't support PAE!
983 The actual amount of total physical memory will either be
984 auto detected or can be forced by using a kernel command line option
985 such as "mem=256M". (Try "man bootparam" or see the documentation of
986 your boot loader (lilo or loadlin) about how to pass options to the
987 kernel at boot time.)
989 If unsure, say "off".
993 depends on !X86_NUMAQ
995 Select this if you have a 32-bit processor and between 1 and 4
996 gigabytes of physical RAM.
1000 depends on !M386 && !M486
1003 Select this if you have a 32-bit processor and more than 4
1004 gigabytes of physical RAM.
1009 depends on EXPERIMENTAL
1010 prompt "Memory split" if EMBEDDED
1014 Select the desired split between kernel and user memory.
1016 If the address range available to the kernel is less than the
1017 physical memory installed, the remaining memory will be available
1018 as "high memory". Accessing high memory is a little more costly
1019 than low memory, as it needs to be mapped into the kernel first.
1020 Note that increasing the kernel address space limits the range
1021 available to user programs, making the address space there
1022 tighter. Selecting anything other than the default 3G/1G split
1023 will also likely make your kernel incompatible with binary-only
1026 If you are not absolutely sure what you are doing, leave this
1030 bool "3G/1G user/kernel split"
1031 config VMSPLIT_3G_OPT
1033 bool "3G/1G user/kernel split (for full 1G low memory)"
1035 bool "2G/2G user/kernel split"
1036 config VMSPLIT_2G_OPT
1038 bool "2G/2G user/kernel split (for full 2G low memory)"
1040 bool "1G/3G user/kernel split"
1045 default 0xB0000000 if VMSPLIT_3G_OPT
1046 default 0x80000000 if VMSPLIT_2G
1047 default 0x78000000 if VMSPLIT_2G_OPT
1048 default 0x40000000 if VMSPLIT_1G
1054 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1057 bool "PAE (Physical Address Extension) Support"
1058 depends on X86_32 && !HIGHMEM4G
1060 PAE is required for NX support, and furthermore enables
1061 larger swapspace support for non-overcommit purposes. It
1062 has the cost of more pagetable lookup overhead, and also
1063 consumes more pagetable space per process.
1065 config ARCH_PHYS_ADDR_T_64BIT
1066 def_bool X86_64 || X86_PAE
1068 config DIRECT_GBPAGES
1069 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1073 Allow the kernel linear mapping to use 1GB pages on CPUs that
1074 support it. This can improve the kernel's performance a tiny bit by
1075 reducing TLB pressure. If in doubt, say "Y".
1077 # Common NUMA Features
1079 bool "Numa Memory Allocation and Scheduler Support"
1081 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1082 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1084 Enable NUMA (Non Uniform Memory Access) support.
1086 The kernel will try to allocate memory used by a CPU on the
1087 local memory controller of the CPU and add some more
1088 NUMA awareness to the kernel.
1090 For 64-bit this is recommended if the system is Intel Core i7
1091 (or later), AMD Opteron, or EM64T NUMA.
1093 For 32-bit this is only needed on (rare) 32-bit-only platforms
1094 that support NUMA topologies, such as NUMAQ / Summit, or if you
1095 boot a 32-bit kernel on a 64-bit NUMA platform.
1097 Otherwise, you should say N.
1099 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1100 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1104 prompt "Old style AMD Opteron NUMA detection"
1105 depends on X86_64 && NUMA && PCI
1107 Enable K8 NUMA node topology detection. You should say Y here if
1108 you have a multi processor AMD K8 system. This uses an old
1109 method to read the NUMA configuration directly from the builtin
1110 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1111 instead, which also takes priority if both are compiled in.
1113 config X86_64_ACPI_NUMA
1115 prompt "ACPI NUMA detection"
1116 depends on X86_64 && NUMA && ACPI && PCI
1119 Enable ACPI SRAT based node topology detection.
1121 # Some NUMA nodes have memory ranges that span
1122 # other nodes. Even though a pfn is valid and
1123 # between a node's start and end pfns, it may not
1124 # reside on that node. See memmap_init_zone()
1126 config NODES_SPAN_OTHER_NODES
1128 depends on X86_64_ACPI_NUMA
1131 bool "NUMA emulation"
1132 depends on X86_64 && NUMA
1134 Enable NUMA emulation. A flat machine will be split
1135 into virtual nodes when booted with "numa=fake=N", where N is the
1136 number of nodes. This is only useful for debugging.
1139 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1141 default "9" if MAXSMP
1142 default "6" if X86_64
1143 default "4" if X86_NUMAQ
1145 depends on NEED_MULTIPLE_NODES
1147 Specify the maximum number of NUMA Nodes available on the target
1148 system. Increases memory reserved to accommodate various tables.
1150 config HAVE_ARCH_BOOTMEM
1152 depends on X86_32 && NUMA
1154 config ARCH_HAVE_MEMORY_PRESENT
1156 depends on X86_32 && DISCONTIGMEM
1158 config NEED_NODE_MEMMAP_SIZE
1160 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1162 config HAVE_ARCH_ALLOC_REMAP
1164 depends on X86_32 && NUMA
1166 config ARCH_FLATMEM_ENABLE
1168 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1170 config ARCH_DISCONTIGMEM_ENABLE
1172 depends on NUMA && X86_32
1174 config ARCH_DISCONTIGMEM_DEFAULT
1176 depends on NUMA && X86_32
1178 config ARCH_SPARSEMEM_DEFAULT
1182 config ARCH_SPARSEMEM_ENABLE
1184 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1185 select SPARSEMEM_STATIC if X86_32
1186 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1188 config ARCH_SELECT_MEMORY_MODEL
1190 depends on ARCH_SPARSEMEM_ENABLE
1192 config ARCH_MEMORY_PROBE
1194 depends on MEMORY_HOTPLUG
1199 bool "Allocate 3rd-level pagetables from highmem"
1200 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1202 The VM uses one page table entry for each page of physical memory.
1203 For systems with a lot of RAM, this can be wasteful of precious
1204 low memory. Setting this option will put user-space page table
1205 entries in high memory.
1207 config X86_CHECK_BIOS_CORRUPTION
1208 bool "Check for low memory corruption"
1210 Periodically check for memory corruption in low memory, which
1211 is suspected to be caused by BIOS. Even when enabled in the
1212 configuration, it is disabled at runtime. Enable it by
1213 setting "memory_corruption_check=1" on the kernel command
1214 line. By default it scans the low 64k of memory every 60
1215 seconds; see the memory_corruption_check_size and
1216 memory_corruption_check_period parameters in
1217 Documentation/kernel-parameters.txt to adjust this.
1219 When enabled with the default parameters, this option has
1220 almost no overhead, as it reserves a relatively small amount
1221 of memory and scans it infrequently. It both detects corruption
1222 and prevents it from affecting the running system.
1224 It is, however, intended as a diagnostic tool; if repeatable
1225 BIOS-originated corruption always affects the same memory,
1226 you can use memmap= to prevent the kernel from using that
1229 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1230 bool "Set the default setting of memory_corruption_check"
1231 depends on X86_CHECK_BIOS_CORRUPTION
1234 Set whether the default state of memory_corruption_check is
1237 config X86_RESERVE_LOW_64K
1238 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1241 Reserve the first 64K of physical RAM on BIOSes that are known
1242 to potentially corrupt that memory range. A numbers of BIOSes are
1243 known to utilize this area during suspend/resume, so it must not
1244 be used by the kernel.
1246 Set this to N if you are absolutely sure that you trust the BIOS
1247 to get all its memory reservations and usages right.
1249 If you have doubts about the BIOS (e.g. suspend/resume does not
1250 work or there's kernel crashes after certain hardware hotplug
1251 events) and it's not AMI or Phoenix, then you might want to enable
1252 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1253 corruption patterns.
1257 config MATH_EMULATION
1259 prompt "Math emulation" if X86_32
1261 Linux can emulate a math coprocessor (used for floating point
1262 operations) if you don't have one. 486DX and Pentium processors have
1263 a math coprocessor built in, 486SX and 386 do not, unless you added
1264 a 487DX or 387, respectively. (The messages during boot time can
1265 give you some hints here ["man dmesg"].) Everyone needs either a
1266 coprocessor or this emulation.
1268 If you don't have a math coprocessor, you need to say Y here; if you
1269 say Y here even though you have a coprocessor, the coprocessor will
1270 be used nevertheless. (This behavior can be changed with the kernel
1271 command line option "no387", which comes handy if your coprocessor
1272 is broken. Try "man bootparam" or see the documentation of your boot
1273 loader (lilo or loadlin) about how to pass options to the kernel at
1274 boot time.) This means that it is a good idea to say Y here if you
1275 intend to use this kernel on different machines.
1277 More information about the internals of the Linux math coprocessor
1278 emulation can be found in <file:arch/x86/math-emu/README>.
1280 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1281 kernel, it won't hurt.
1284 bool "MTRR (Memory Type Range Register) support"
1286 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1287 the Memory Type Range Registers (MTRRs) may be used to control
1288 processor access to memory ranges. This is most useful if you have
1289 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1290 allows bus write transfers to be combined into a larger transfer
1291 before bursting over the PCI/AGP bus. This can increase performance
1292 of image write operations 2.5 times or more. Saying Y here creates a
1293 /proc/mtrr file which may be used to manipulate your processor's
1294 MTRRs. Typically the X server should use this.
1296 This code has a reasonably generic interface so that similar
1297 control registers on other processors can be easily supported
1300 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1301 Registers (ARRs) which provide a similar functionality to MTRRs. For
1302 these, the ARRs are used to emulate the MTRRs.
1303 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1304 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1305 write-combining. All of these processors are supported by this code
1306 and it makes sense to say Y here if you have one of them.
1308 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1309 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1310 can lead to all sorts of problems, so it's good to say Y here.
1312 You can safely say Y even if your machine doesn't have MTRRs, you'll
1313 just add about 9 KB to your kernel.
1315 See <file:Documentation/x86/mtrr.txt> for more information.
1317 config MTRR_SANITIZER
1319 prompt "MTRR cleanup support"
1322 Convert MTRR layout from continuous to discrete, so X drivers can
1323 add writeback entries.
1325 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1326 The largest mtrr entry size for a continuous block can be set with
1331 config MTRR_SANITIZER_ENABLE_DEFAULT
1332 int "MTRR cleanup enable value (0-1)"
1335 depends on MTRR_SANITIZER
1337 Enable mtrr cleanup default value
1339 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1340 int "MTRR cleanup spare reg num (0-7)"
1343 depends on MTRR_SANITIZER
1345 mtrr cleanup spare entries default, it can be changed via
1346 mtrr_spare_reg_nr=N on the kernel command line.
1350 prompt "x86 PAT support"
1353 Use PAT attributes to setup page level cache control.
1355 PATs are the modern equivalents of MTRRs and are much more
1356 flexible than MTRRs.
1358 Say N here if you see bootup problems (boot crash, boot hang,
1359 spontaneous reboots) or a non-working video driver.
1364 bool "EFI runtime service support"
1367 This enables the kernel to use EFI runtime services that are
1368 available (such as the EFI variable services).
1370 This option is only useful on systems that have EFI firmware.
1371 In addition, you should use the latest ELILO loader available
1372 at <http://elilo.sourceforge.net> in order to take advantage
1373 of EFI runtime services. However, even with this option, the
1374 resultant kernel should continue to boot on existing non-EFI
1379 prompt "Enable seccomp to safely compute untrusted bytecode"
1381 This kernel feature is useful for number crunching applications
1382 that may need to compute untrusted bytecode during their
1383 execution. By using pipes or other transports made available to
1384 the process as file descriptors supporting the read/write
1385 syscalls, it's possible to isolate those applications in
1386 their own address space using seccomp. Once seccomp is
1387 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1388 and the task is only allowed to execute a few safe syscalls
1389 defined by each seccomp mode.
1391 If unsure, say Y. Only embedded should say N here.
1393 config CC_STACKPROTECTOR_ALL
1396 config CC_STACKPROTECTOR
1397 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1398 select CC_STACKPROTECTOR_ALL
1400 This option turns on the -fstack-protector GCC feature. This
1401 feature puts, at the beginning of functions, a canary value on
1402 the stack just before the return address, and validates
1403 the value just before actually returning. Stack based buffer
1404 overflows (that need to overwrite this return address) now also
1405 overwrite the canary, which gets detected and the attack is then
1406 neutralized via a kernel panic.
1408 This feature requires gcc version 4.2 or above, or a distribution
1409 gcc with the feature backported. Older versions are automatically
1410 detected and for those versions, this configuration option is
1411 ignored. (and a warning is printed during bootup)
1413 source kernel/Kconfig.hz
1416 bool "kexec system call"
1418 kexec is a system call that implements the ability to shutdown your
1419 current kernel, and to start another kernel. It is like a reboot
1420 but it is independent of the system firmware. And like a reboot
1421 you can start any kernel with it, not just Linux.
1423 The name comes from the similarity to the exec system call.
1425 It is an ongoing process to be certain the hardware in a machine
1426 is properly shutdown, so do not be surprised if this code does not
1427 initially work for you. It may help to enable device hotplugging
1428 support. As of this writing the exact hardware interface is
1429 strongly in flux, so no good recommendation can be made.
1432 bool "kernel crash dumps"
1433 depends on X86_64 || (X86_32 && HIGHMEM)
1435 Generate crash dump after being started by kexec.
1436 This should be normally only set in special crash dump kernels
1437 which are loaded in the main kernel with kexec-tools into
1438 a specially reserved region and then later executed after
1439 a crash by kdump/kexec. The crash dump kernel must be compiled
1440 to a memory address not used by the main kernel or BIOS using
1441 PHYSICAL_START, or it must be built as a relocatable image
1442 (CONFIG_RELOCATABLE=y).
1443 For more details see Documentation/kdump/kdump.txt
1446 bool "kexec jump (EXPERIMENTAL)"
1447 depends on EXPERIMENTAL
1448 depends on KEXEC && HIBERNATION
1450 Jump between original kernel and kexeced kernel and invoke
1451 code in physical address mode via KEXEC
1453 config PHYSICAL_START
1454 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1455 default "0x1000000" if X86_NUMAQ
1456 default "0x200000" if X86_64
1459 This gives the physical address where the kernel is loaded.
1461 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1462 bzImage will decompress itself to above physical address and
1463 run from there. Otherwise, bzImage will run from the address where
1464 it has been loaded by the boot loader and will ignore above physical
1467 In normal kdump cases one does not have to set/change this option
1468 as now bzImage can be compiled as a completely relocatable image
1469 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1470 address. This option is mainly useful for the folks who don't want
1471 to use a bzImage for capturing the crash dump and want to use a
1472 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1473 to be specifically compiled to run from a specific memory area
1474 (normally a reserved region) and this option comes handy.
1476 So if you are using bzImage for capturing the crash dump, leave
1477 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1478 Otherwise if you plan to use vmlinux for capturing the crash dump
1479 change this value to start of the reserved region (Typically 16MB
1480 0x1000000). In other words, it can be set based on the "X" value as
1481 specified in the "crashkernel=YM@XM" command line boot parameter
1482 passed to the panic-ed kernel. Typically this parameter is set as
1483 crashkernel=64M@16M. Please take a look at
1484 Documentation/kdump/kdump.txt for more details about crash dumps.
1486 Usage of bzImage for capturing the crash dump is recommended as
1487 one does not have to build two kernels. Same kernel can be used
1488 as production kernel and capture kernel. Above option should have
1489 gone away after relocatable bzImage support is introduced. But it
1490 is present because there are users out there who continue to use
1491 vmlinux for dump capture. This option should go away down the
1494 Don't change this unless you know what you are doing.
1497 bool "Build a relocatable kernel (EXPERIMENTAL)"
1498 depends on EXPERIMENTAL
1500 This builds a kernel image that retains relocation information
1501 so it can be loaded someplace besides the default 1MB.
1502 The relocations tend to make the kernel binary about 10% larger,
1503 but are discarded at runtime.
1505 One use is for the kexec on panic case where the recovery kernel
1506 must live at a different physical address than the primary
1509 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1510 it has been loaded at and the compile time physical address
1511 (CONFIG_PHYSICAL_START) is ignored.
1513 config PHYSICAL_ALIGN
1515 prompt "Alignment value to which kernel should be aligned" if X86_32
1516 default "0x100000" if X86_32
1517 default "0x200000" if X86_64
1518 range 0x2000 0x400000
1520 This value puts the alignment restrictions on physical address
1521 where kernel is loaded and run from. Kernel is compiled for an
1522 address which meets above alignment restriction.
1524 If bootloader loads the kernel at a non-aligned address and
1525 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1526 address aligned to above value and run from there.
1528 If bootloader loads the kernel at a non-aligned address and
1529 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1530 load address and decompress itself to the address it has been
1531 compiled for and run from there. The address for which kernel is
1532 compiled already meets above alignment restrictions. Hence the
1533 end result is that kernel runs from a physical address meeting
1534 above alignment restrictions.
1536 Don't change this unless you know what you are doing.
1539 bool "Support for hot-pluggable CPUs"
1540 depends on SMP && HOTPLUG
1542 Say Y here to allow turning CPUs off and on. CPUs can be
1543 controlled through /sys/devices/system/cpu.
1544 ( Note: power management support will enable this option
1545 automatically on SMP systems. )
1546 Say N if you want to disable CPU hotplug.
1550 prompt "Compat VDSO support"
1551 depends on X86_32 || IA32_EMULATION
1553 Map the 32-bit VDSO to the predictable old-style address too.
1555 Say N here if you are running a sufficiently recent glibc
1556 version (2.3.3 or later), to remove the high-mapped
1557 VDSO mapping and to exclusively use the randomized VDSO.
1562 bool "Built-in kernel command line"
1565 Allow for specifying boot arguments to the kernel at
1566 build time. On some systems (e.g. embedded ones), it is
1567 necessary or convenient to provide some or all of the
1568 kernel boot arguments with the kernel itself (that is,
1569 to not rely on the boot loader to provide them.)
1571 To compile command line arguments into the kernel,
1572 set this option to 'Y', then fill in the
1573 the boot arguments in CONFIG_CMDLINE.
1575 Systems with fully functional boot loaders (i.e. non-embedded)
1576 should leave this option set to 'N'.
1579 string "Built-in kernel command string"
1580 depends on CMDLINE_BOOL
1583 Enter arguments here that should be compiled into the kernel
1584 image and used at boot time. If the boot loader provides a
1585 command line at boot time, it is appended to this string to
1586 form the full kernel command line, when the system boots.
1588 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1589 change this behavior.
1591 In most cases, the command line (whether built-in or provided
1592 by the boot loader) should specify the device for the root
1595 config CMDLINE_OVERRIDE
1596 bool "Built-in command line overrides boot loader arguments"
1598 depends on CMDLINE_BOOL
1600 Set this option to 'Y' to have the kernel ignore the boot loader
1601 command line, and use ONLY the built-in command line.
1603 This is used to work around broken boot loaders. This should
1604 be set to 'N' under normal conditions.
1608 config ARCH_ENABLE_MEMORY_HOTPLUG
1610 depends on X86_64 || (X86_32 && HIGHMEM)
1612 config ARCH_ENABLE_MEMORY_HOTREMOVE
1614 depends on MEMORY_HOTPLUG
1616 config HAVE_ARCH_EARLY_PFN_TO_NID
1620 menu "Power management and ACPI options"
1622 config ARCH_HIBERNATION_HEADER
1624 depends on X86_64 && HIBERNATION
1626 source "kernel/power/Kconfig"
1628 source "drivers/acpi/Kconfig"
1633 depends on APM || APM_MODULE
1636 tristate "APM (Advanced Power Management) BIOS support"
1637 depends on X86_32 && PM_SLEEP
1639 APM is a BIOS specification for saving power using several different
1640 techniques. This is mostly useful for battery powered laptops with
1641 APM compliant BIOSes. If you say Y here, the system time will be
1642 reset after a RESUME operation, the /proc/apm device will provide
1643 battery status information, and user-space programs will receive
1644 notification of APM "events" (e.g. battery status change).
1646 If you select "Y" here, you can disable actual use of the APM
1647 BIOS by passing the "apm=off" option to the kernel at boot time.
1649 Note that the APM support is almost completely disabled for
1650 machines with more than one CPU.
1652 In order to use APM, you will need supporting software. For location
1653 and more information, read <file:Documentation/power/pm.txt> and the
1654 Battery Powered Linux mini-HOWTO, available from
1655 <http://www.tldp.org/docs.html#howto>.
1657 This driver does not spin down disk drives (see the hdparm(8)
1658 manpage ("man 8 hdparm") for that), and it doesn't turn off
1659 VESA-compliant "green" monitors.
1661 This driver does not support the TI 4000M TravelMate and the ACER
1662 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1663 desktop machines also don't have compliant BIOSes, and this driver
1664 may cause those machines to panic during the boot phase.
1666 Generally, if you don't have a battery in your machine, there isn't
1667 much point in using this driver and you should say N. If you get
1668 random kernel OOPSes or reboots that don't seem to be related to
1669 anything, try disabling/enabling this option (or disabling/enabling
1672 Some other things you should try when experiencing seemingly random,
1675 1) make sure that you have enough swap space and that it is
1677 2) pass the "no-hlt" option to the kernel
1678 3) switch on floating point emulation in the kernel and pass
1679 the "no387" option to the kernel
1680 4) pass the "floppy=nodma" option to the kernel
1681 5) pass the "mem=4M" option to the kernel (thereby disabling
1682 all but the first 4 MB of RAM)
1683 6) make sure that the CPU is not over clocked.
1684 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1685 8) disable the cache from your BIOS settings
1686 9) install a fan for the video card or exchange video RAM
1687 10) install a better fan for the CPU
1688 11) exchange RAM chips
1689 12) exchange the motherboard.
1691 To compile this driver as a module, choose M here: the
1692 module will be called apm.
1696 config APM_IGNORE_USER_SUSPEND
1697 bool "Ignore USER SUSPEND"
1699 This option will ignore USER SUSPEND requests. On machines with a
1700 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1701 series notebooks, it is necessary to say Y because of a BIOS bug.
1703 config APM_DO_ENABLE
1704 bool "Enable PM at boot time"
1706 Enable APM features at boot time. From page 36 of the APM BIOS
1707 specification: "When disabled, the APM BIOS does not automatically
1708 power manage devices, enter the Standby State, enter the Suspend
1709 State, or take power saving steps in response to CPU Idle calls."
1710 This driver will make CPU Idle calls when Linux is idle (unless this
1711 feature is turned off -- see "Do CPU IDLE calls", below). This
1712 should always save battery power, but more complicated APM features
1713 will be dependent on your BIOS implementation. You may need to turn
1714 this option off if your computer hangs at boot time when using APM
1715 support, or if it beeps continuously instead of suspending. Turn
1716 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1717 T400CDT. This is off by default since most machines do fine without
1721 bool "Make CPU Idle calls when idle"
1723 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1724 On some machines, this can activate improved power savings, such as
1725 a slowed CPU clock rate, when the machine is idle. These idle calls
1726 are made after the idle loop has run for some length of time (e.g.,
1727 333 mS). On some machines, this will cause a hang at boot time or
1728 whenever the CPU becomes idle. (On machines with more than one CPU,
1729 this option does nothing.)
1731 config APM_DISPLAY_BLANK
1732 bool "Enable console blanking using APM"
1734 Enable console blanking using the APM. Some laptops can use this to
1735 turn off the LCD backlight when the screen blanker of the Linux
1736 virtual console blanks the screen. Note that this is only used by
1737 the virtual console screen blanker, and won't turn off the backlight
1738 when using the X Window system. This also doesn't have anything to
1739 do with your VESA-compliant power-saving monitor. Further, this
1740 option doesn't work for all laptops -- it might not turn off your
1741 backlight at all, or it might print a lot of errors to the console,
1742 especially if you are using gpm.
1744 config APM_ALLOW_INTS
1745 bool "Allow interrupts during APM BIOS calls"
1747 Normally we disable external interrupts while we are making calls to
1748 the APM BIOS as a measure to lessen the effects of a badly behaving
1749 BIOS implementation. The BIOS should reenable interrupts if it
1750 needs to. Unfortunately, some BIOSes do not -- especially those in
1751 many of the newer IBM Thinkpads. If you experience hangs when you
1752 suspend, try setting this to Y. Otherwise, say N.
1756 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1758 source "drivers/cpuidle/Kconfig"
1760 source "drivers/idle/Kconfig"
1765 menu "Bus options (PCI etc.)"
1770 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1772 Find out whether you have a PCI motherboard. PCI is the name of a
1773 bus system, i.e. the way the CPU talks to the other stuff inside
1774 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1775 VESA. If you have PCI, say Y, otherwise N.
1778 prompt "PCI access mode"
1779 depends on X86_32 && PCI
1782 On PCI systems, the BIOS can be used to detect the PCI devices and
1783 determine their configuration. However, some old PCI motherboards
1784 have BIOS bugs and may crash if this is done. Also, some embedded
1785 PCI-based systems don't have any BIOS at all. Linux can also try to
1786 detect the PCI hardware directly without using the BIOS.
1788 With this option, you can specify how Linux should detect the
1789 PCI devices. If you choose "BIOS", the BIOS will be used,
1790 if you choose "Direct", the BIOS won't be used, and if you
1791 choose "MMConfig", then PCI Express MMCONFIG will be used.
1792 If you choose "Any", the kernel will try MMCONFIG, then the
1793 direct access method and falls back to the BIOS if that doesn't
1794 work. If unsure, go with the default, which is "Any".
1799 config PCI_GOMMCONFIG
1816 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1818 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1821 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1825 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1829 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1836 bool "Support mmconfig PCI config space access"
1837 depends on X86_64 && PCI && ACPI
1840 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1841 depends on PCI_MSI && ACPI && EXPERIMENTAL
1843 DMA remapping (DMAR) devices support enables independent address
1844 translations for Direct Memory Access (DMA) from devices.
1845 These DMA remapping devices are reported via ACPI tables
1846 and include PCI device scope covered by these DMA
1849 config DMAR_DEFAULT_ON
1851 prompt "Enable DMA Remapping Devices by default"
1854 Selecting this option will enable a DMAR device at boot time if
1855 one is found. If this option is not selected, DMAR support can
1856 be enabled by passing intel_iommu=on to the kernel. It is
1857 recommended you say N here while the DMAR code remains
1862 prompt "Support for Graphics workaround"
1865 Current Graphics drivers tend to use physical address
1866 for DMA and avoid using DMA APIs. Setting this config
1867 option permits the IOMMU driver to set a unity map for
1868 all the OS-visible memory. Hence the driver can continue
1869 to use physical addresses for DMA.
1871 config DMAR_FLOPPY_WA
1875 Floppy disk drivers are know to bypass DMA API calls
1876 thereby failing to work when IOMMU is enabled. This
1877 workaround will setup a 1:1 mapping for the first
1878 16M to make floppy (an ISA device) work.
1881 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1882 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1884 Supports Interrupt remapping for IO-APIC and MSI devices.
1885 To use x2apic mode in the CPU's which support x2APIC enhancements or
1886 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1888 source "drivers/pci/pcie/Kconfig"
1890 source "drivers/pci/Kconfig"
1892 # x86_64 have no ISA slots, but do have ISA-style DMA.
1901 Find out whether you have ISA slots on your motherboard. ISA is the
1902 name of a bus system, i.e. the way the CPU talks to the other stuff
1903 inside your box. Other bus systems are PCI, EISA, MicroChannel
1904 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1905 newer boards don't support it. If you have ISA, say Y, otherwise N.
1911 The Extended Industry Standard Architecture (EISA) bus was
1912 developed as an open alternative to the IBM MicroChannel bus.
1914 The EISA bus provided some of the features of the IBM MicroChannel
1915 bus while maintaining backward compatibility with cards made for
1916 the older ISA bus. The EISA bus saw limited use between 1988 and
1917 1995 when it was made obsolete by the PCI bus.
1919 Say Y here if you are building a kernel for an EISA-based machine.
1923 source "drivers/eisa/Kconfig"
1928 MicroChannel Architecture is found in some IBM PS/2 machines and
1929 laptops. It is a bus system similar to PCI or ISA. See
1930 <file:Documentation/mca.txt> (and especially the web page given
1931 there) before attempting to build an MCA bus kernel.
1933 source "drivers/mca/Kconfig"
1936 tristate "NatSemi SCx200 support"
1938 This provides basic support for National Semiconductor's
1939 (now AMD's) Geode processors. The driver probes for the
1940 PCI-IDs of several on-chip devices, so its a good dependency
1941 for other scx200_* drivers.
1943 If compiled as a module, the driver is named scx200.
1945 config SCx200HR_TIMER
1946 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1947 depends on SCx200 && GENERIC_TIME
1950 This driver provides a clocksource built upon the on-chip
1951 27MHz high-resolution timer. Its also a workaround for
1952 NSC Geode SC-1100's buggy TSC, which loses time when the
1953 processor goes idle (as is done by the scheduler). The
1954 other workaround is idle=poll boot option.
1956 config GEODE_MFGPT_TIMER
1958 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1959 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1961 This driver provides a clock event source based on the MFGPT
1962 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1963 MFGPTs have a better resolution and max interval than the
1964 generic PIT, and are suitable for use as high-res timers.
1967 bool "One Laptop Per Child support"
1970 Add support for detecting the unique features of the OLPC
1977 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1979 source "drivers/pcmcia/Kconfig"
1981 source "drivers/pci/hotplug/Kconfig"
1986 menu "Executable file formats / Emulations"
1988 source "fs/Kconfig.binfmt"
1990 config IA32_EMULATION
1991 bool "IA32 Emulation"
1993 select COMPAT_BINFMT_ELF
1995 Include code to run 32-bit programs under a 64-bit kernel. You should
1996 likely turn this on, unless you're 100% sure that you don't have any
1997 32-bit programs left.
2000 tristate "IA32 a.out support"
2001 depends on IA32_EMULATION
2003 Support old a.out binaries in the 32bit emulation.
2007 depends on IA32_EMULATION
2009 config COMPAT_FOR_U64_ALIGNMENT
2013 config SYSVIPC_COMPAT
2015 depends on COMPAT && SYSVIPC
2020 config HAVE_ATOMIC_IOMAP
2024 source "net/Kconfig"
2026 source "drivers/Kconfig"
2028 source "drivers/firmware/Kconfig"
2032 source "arch/x86/Kconfig.debug"
2034 source "security/Kconfig"
2036 source "crypto/Kconfig"
2038 source "arch/x86/kvm/Kconfig"
2040 source "lib/Kconfig"
projects / linux-2.6 / blob