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_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
38 select HAVE_ARCH_KGDB if !X86_VOYAGER
39 select HAVE_ARCH_TRACEHOOK
40 select HAVE_GENERIC_DMA_COHERENT if X86_32
41 select HAVE_EFFICIENT_UNALIGNED_ACCESS
42 select USER_STACKTRACE_SUPPORT
46 default "arch/x86/configs/i386_defconfig" if X86_32
47 default "arch/x86/configs/x86_64_defconfig" if X86_64
52 config GENERIC_CMOS_UPDATE
55 config CLOCKSOURCE_WATCHDOG
58 config GENERIC_CLOCKEVENTS
61 config GENERIC_CLOCKEVENTS_BROADCAST
63 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
65 config LOCKDEP_SUPPORT
68 config STACKTRACE_SUPPORT
71 config HAVE_LATENCYTOP_SUPPORT
74 config FAST_CMPXCHG_LOCAL
87 config GENERIC_ISA_DMA
96 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
98 config GENERIC_BUG_RELATIVE_POINTERS
101 config GENERIC_HWEIGHT
107 config ARCH_MAY_HAVE_PC_FDC
110 config RWSEM_GENERIC_SPINLOCK
113 config RWSEM_XCHGADD_ALGORITHM
116 config ARCH_HAS_CPU_IDLE_WAIT
119 config GENERIC_CALIBRATE_DELAY
122 config GENERIC_TIME_VSYSCALL
126 config ARCH_HAS_CPU_RELAX
129 config ARCH_HAS_DEFAULT_IDLE
132 config ARCH_HAS_CACHE_LINE_SIZE
135 config HAVE_SETUP_PER_CPU_AREA
136 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
138 config HAVE_CPUMASK_OF_CPU_MAP
141 config ARCH_HIBERNATION_POSSIBLE
143 depends on !SMP || !X86_VOYAGER
145 config ARCH_SUSPEND_POSSIBLE
147 depends on !X86_VOYAGER
153 config ARCH_POPULATES_NODE_MAP
160 config ARCH_SUPPORTS_OPTIMIZED_INLINING
163 # Use the generic interrupt handling code in kernel/irq/:
164 config GENERIC_HARDIRQS
168 config GENERIC_IRQ_PROBE
172 config GENERIC_PENDING_IRQ
174 depends on GENERIC_HARDIRQS && SMP
179 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
182 config USE_GENERIC_SMP_HELPERS
188 depends on X86_32 && SMP
192 depends on X86_64 && SMP
197 depends on (X86_32 && !X86_VOYAGER) || X86_64
200 config X86_BIOS_REBOOT
202 depends on !X86_VOYAGER
205 config X86_TRAMPOLINE
207 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
212 source "init/Kconfig"
213 source "kernel/Kconfig.freezer"
215 menu "Processor type and features"
217 source "kernel/time/Kconfig"
220 bool "Symmetric multi-processing support"
222 This enables support for systems with more than one CPU. If you have
223 a system with only one CPU, like most personal computers, say N. If
224 you have a system with more than one CPU, say Y.
226 If you say N here, the kernel will run on single and multiprocessor
227 machines, but will use only one CPU of a multiprocessor machine. If
228 you say Y here, the kernel will run on many, but not all,
229 singleprocessor machines. On a singleprocessor machine, the kernel
230 will run faster if you say N here.
232 Note that if you say Y here and choose architecture "586" or
233 "Pentium" under "Processor family", the kernel will not work on 486
234 architectures. Similarly, multiprocessor kernels for the "PPro"
235 architecture may not work on all Pentium based boards.
237 People using multiprocessor machines who say Y here should also say
238 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
239 Management" code will be disabled if you say Y here.
241 See also <file:Documentation/i386/IO-APIC.txt>,
242 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
243 <http://www.tldp.org/docs.html#howto>.
245 If you don't know what to do here, say N.
247 config X86_HAS_BOOT_CPU_ID
249 depends on X86_VOYAGER
252 bool "Support sparse irq numbering"
253 depends on PCI_MSI || HT_IRQ
255 This enables support for sparse irqs. This is useful for distro
256 kernels that want to define a high CONFIG_NR_CPUS value but still
257 want to have low kernel memory footprint on smaller machines.
259 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
260 out the irq_desc[] array in a more NUMA-friendly way. )
262 If you don't know what to do here, say N.
264 config NUMA_MIGRATE_IRQ_DESC
265 bool "Move irq desc when changing irq smp_affinity"
266 depends on SPARSE_IRQ && NUMA
269 This enables moving irq_desc to cpu/node that irq will use handled.
271 If you don't know what to do here, say N.
273 config X86_FIND_SMP_CONFIG
275 depends on X86_MPPARSE || X86_VOYAGER
278 bool "Enable MPS table" if ACPI
280 depends on X86_LOCAL_APIC
282 For old smp systems that do not have proper acpi support. Newer systems
283 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
286 prompt "Subarchitecture Type"
292 Choose this option if your computer is a standard PC or compatible.
298 Select this for an AMD Elan processor.
300 Do not use this option for K6/Athlon/Opteron processors!
302 If unsure, choose "PC-compatible" instead.
306 depends on X86_32 && (SMP || BROKEN) && !PCI
308 Voyager is an MCA-based 32-way capable SMP architecture proprietary
309 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
313 If you do not specifically know you have a Voyager based machine,
314 say N here, otherwise the kernel you build will not be bootable.
316 config X86_GENERICARCH
317 bool "Generic architecture"
320 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
321 subarchitectures. It is intended for a generic binary kernel.
322 if you select them all, kernel will probe it one by one. and will
328 bool "NUMAQ (IBM/Sequent)"
329 depends on SMP && X86_32 && PCI && X86_MPPARSE
332 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
333 NUMA multiquad box. This changes the way that processors are
334 bootstrapped, and uses Clustered Logical APIC addressing mode instead
335 of Flat Logical. You will need a new lynxer.elf file to flash your
336 firmware with - send email to <Martin.Bligh@us.ibm.com>.
339 bool "Summit/EXA (IBM x440)"
340 depends on X86_32 && SMP
342 This option is needed for IBM systems that use the Summit/EXA chipset.
343 In particular, it is needed for the x440.
346 bool "Support for Unisys ES7000 IA32 series"
347 depends on X86_32 && SMP
349 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
350 supposed to run on an IA32-based Unisys ES7000 system.
353 bool "Support for big SMP systems with more than 8 CPUs"
354 depends on X86_32 && SMP
356 This option is needed for the systems that have more than 8 CPUs
357 and if the system is not of any sub-arch type above.
362 bool "Support for ScaleMP vSMP"
364 depends on X86_64 && PCI
366 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
367 supposed to run on these EM64T-based machines. Only choose this option
368 if you have one of these machines.
373 bool "SGI 320/540 (Visual Workstation)"
374 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
376 The SGI Visual Workstation series is an IA32-based workstation
377 based on SGI systems chips with some legacy PC hardware attached.
379 Say Y here to create a kernel to run on the SGI 320 or 540.
381 A kernel compiled for the Visual Workstation will run on general
382 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
385 bool "RDC R-321x SoC"
388 select X86_REBOOTFIXUPS
390 This option is needed for RDC R-321x system-on-chip, also known
392 If you don't have one of these chips, you should say N here.
394 config SCHED_OMIT_FRAME_POINTER
396 prompt "Single-depth WCHAN output"
399 Calculate simpler /proc/<PID>/wchan values. If this option
400 is disabled then wchan values will recurse back to the
401 caller function. This provides more accurate wchan values,
402 at the expense of slightly more scheduling overhead.
404 If in doubt, say "Y".
406 menuconfig PARAVIRT_GUEST
407 bool "Paravirtualized guest support"
409 Say Y here to get to see options related to running Linux under
410 various hypervisors. This option alone does not add any kernel code.
412 If you say N, all options in this submenu will be skipped and disabled.
416 source "arch/x86/xen/Kconfig"
419 bool "VMI Guest support"
422 depends on !X86_VOYAGER
424 VMI provides a paravirtualized interface to the VMware ESX server
425 (it could be used by other hypervisors in theory too, but is not
426 at the moment), by linking the kernel to a GPL-ed ROM module
427 provided by the hypervisor.
430 bool "KVM paravirtualized clock"
432 select PARAVIRT_CLOCK
433 depends on !X86_VOYAGER
435 Turning on this option will allow you to run a paravirtualized clock
436 when running over the KVM hypervisor. Instead of relying on a PIT
437 (or probably other) emulation by the underlying device model, the host
438 provides the guest with timing infrastructure such as time of day, and
442 bool "KVM Guest support"
444 depends on !X86_VOYAGER
446 This option enables various optimizations for running under the KVM
449 source "arch/x86/lguest/Kconfig"
452 bool "Enable paravirtualization code"
453 depends on !X86_VOYAGER
455 This changes the kernel so it can modify itself when it is run
456 under a hypervisor, potentially improving performance significantly
457 over full virtualization. However, when run without a hypervisor
458 the kernel is theoretically slower and slightly larger.
460 config PARAVIRT_CLOCK
466 config PARAVIRT_DEBUG
467 bool "paravirt-ops debugging"
468 depends on PARAVIRT && DEBUG_KERNEL
470 Enable to debug paravirt_ops internals. Specifically, BUG if
471 a paravirt_op is missing when it is called.
476 This option adds a kernel parameter 'memtest', which allows memtest
478 memtest=0, mean disabled; -- default
479 memtest=1, mean do 1 test pattern;
481 memtest=4, mean do 4 test patterns.
482 If you are unsure how to answer this question, answer N.
484 config X86_SUMMIT_NUMA
486 depends on X86_32 && NUMA && X86_GENERICARCH
488 config X86_CYCLONE_TIMER
490 depends on X86_GENERICARCH
492 source "arch/x86/Kconfig.cpu"
496 prompt "HPET Timer Support" if X86_32
498 Use the IA-PC HPET (High Precision Event Timer) to manage
499 time in preference to the PIT and RTC, if a HPET is
501 HPET is the next generation timer replacing legacy 8254s.
502 The HPET provides a stable time base on SMP
503 systems, unlike the TSC, but it is more expensive to access,
504 as it is off-chip. You can find the HPET spec at
505 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
507 You can safely choose Y here. However, HPET will only be
508 activated if the platform and the BIOS support this feature.
509 Otherwise the 8254 will be used for timing services.
511 Choose N to continue using the legacy 8254 timer.
513 config HPET_EMULATE_RTC
515 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
517 # Mark as embedded because too many people got it wrong.
518 # The code disables itself when not needed.
521 bool "Enable DMI scanning" if EMBEDDED
523 Enabled scanning of DMI to identify machine quirks. Say Y
524 here unless you have verified that your setup is not
525 affected by entries in the DMI blacklist. Required by PNP
529 bool "GART IOMMU support" if EMBEDDED
533 depends on X86_64 && PCI
535 Support for full DMA access of devices with 32bit memory access only
536 on systems with more than 3GB. This is usually needed for USB,
537 sound, many IDE/SATA chipsets and some other devices.
538 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
539 based hardware IOMMU and a software bounce buffer based IOMMU used
540 on Intel systems and as fallback.
541 The code is only active when needed (enough memory and limited
542 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
546 bool "IBM Calgary IOMMU support"
548 depends on X86_64 && PCI && EXPERIMENTAL
550 Support for hardware IOMMUs in IBM's xSeries x366 and x460
551 systems. Needed to run systems with more than 3GB of memory
552 properly with 32-bit PCI devices that do not support DAC
553 (Double Address Cycle). Calgary also supports bus level
554 isolation, where all DMAs pass through the IOMMU. This
555 prevents them from going anywhere except their intended
556 destination. This catches hard-to-find kernel bugs and
557 mis-behaving drivers and devices that do not use the DMA-API
558 properly to set up their DMA buffers. The IOMMU can be
559 turned off at boot time with the iommu=off parameter.
560 Normally the kernel will make the right choice by itself.
563 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
565 prompt "Should Calgary be enabled by default?"
566 depends on CALGARY_IOMMU
568 Should Calgary be enabled by default? if you choose 'y', Calgary
569 will be used (if it exists). If you choose 'n', Calgary will not be
570 used even if it exists. If you choose 'n' and would like to use
571 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
575 bool "AMD IOMMU support"
578 depends on X86_64 && PCI && ACPI
580 With this option you can enable support for AMD IOMMU hardware in
581 your system. An IOMMU is a hardware component which provides
582 remapping of DMA memory accesses from devices. With an AMD IOMMU you
583 can isolate the the DMA memory of different devices and protect the
584 system from misbehaving device drivers or hardware.
586 You can find out if your system has an AMD IOMMU if you look into
587 your BIOS for an option to enable it or if you have an IVRS ACPI
590 config AMD_IOMMU_STATS
591 bool "Export AMD IOMMU statistics to debugfs"
595 This option enables code in the AMD IOMMU driver to collect various
596 statistics about whats happening in the driver and exports that
597 information to userspace via debugfs.
600 # need this always selected by IOMMU for the VIA workaround
604 Support for software bounce buffers used on x86-64 systems
605 which don't have a hardware IOMMU (e.g. the current generation
606 of Intel's x86-64 CPUs). Using this PCI devices which can only
607 access 32-bits of memory can be used on systems with more than
608 3 GB of memory. If unsure, say Y.
611 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
614 def_bool (AMD_IOMMU || DMAR)
617 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
618 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
619 select CPUMASK_OFFSTACK
622 Configure maximum number of CPUS and NUMA Nodes for this architecture.
626 int "Maximum number of CPUs" if SMP && !MAXSMP
627 range 2 512 if SMP && !MAXSMP
629 default "4096" if MAXSMP
630 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
633 This allows you to specify the maximum number of CPUs which this
634 kernel will support. The maximum supported value is 512 and the
635 minimum value which makes sense is 2.
637 This is purely to save memory - each supported CPU adds
638 approximately eight kilobytes to the kernel image.
641 bool "SMT (Hyperthreading) scheduler support"
644 SMT scheduler support improves the CPU scheduler's decision making
645 when dealing with Intel Pentium 4 chips with HyperThreading at a
646 cost of slightly increased overhead in some places. If unsure say
651 prompt "Multi-core scheduler support"
654 Multi-core scheduler support improves the CPU scheduler's decision
655 making when dealing with multi-core CPU chips at a cost of slightly
656 increased overhead in some places. If unsure say N here.
658 source "kernel/Kconfig.preempt"
661 bool "Local APIC support on uniprocessors"
662 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
664 A local APIC (Advanced Programmable Interrupt Controller) is an
665 integrated interrupt controller in the CPU. If you have a single-CPU
666 system which has a processor with a local APIC, you can say Y here to
667 enable and use it. If you say Y here even though your machine doesn't
668 have a local APIC, then the kernel will still run with no slowdown at
669 all. The local APIC supports CPU-generated self-interrupts (timer,
670 performance counters), and the NMI watchdog which detects hard
674 bool "IO-APIC support on uniprocessors"
675 depends on X86_UP_APIC
677 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
678 SMP-capable replacement for PC-style interrupt controllers. Most
679 SMP systems and many recent uniprocessor systems have one.
681 If you have a single-CPU system with an IO-APIC, you can say Y here
682 to use it. If you say Y here even though your machine doesn't have
683 an IO-APIC, then the kernel will still run with no slowdown at all.
685 config X86_LOCAL_APIC
687 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
691 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
693 config X86_VISWS_APIC
695 depends on X86_32 && X86_VISWS
697 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
698 bool "Reroute for broken boot IRQs"
700 depends on X86_IO_APIC
702 This option enables a workaround that fixes a source of
703 spurious interrupts. This is recommended when threaded
704 interrupt handling is used on systems where the generation of
705 superfluous "boot interrupts" cannot be disabled.
707 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
708 entry in the chipset's IO-APIC is masked (as, e.g. the RT
709 kernel does during interrupt handling). On chipsets where this
710 boot IRQ generation cannot be disabled, this workaround keeps
711 the original IRQ line masked so that only the equivalent "boot
712 IRQ" is delivered to the CPUs. The workaround also tells the
713 kernel to set up the IRQ handler on the boot IRQ line. In this
714 way only one interrupt is delivered to the kernel. Otherwise
715 the spurious second interrupt may cause the kernel to bring
716 down (vital) interrupt lines.
718 Only affects "broken" chipsets. Interrupt sharing may be
719 increased on these systems.
722 bool "Machine Check Exception"
723 depends on !X86_VOYAGER
725 Machine Check Exception support allows the processor to notify the
726 kernel if it detects a problem (e.g. overheating, component failure).
727 The action the kernel takes depends on the severity of the problem,
728 ranging from a warning message on the console, to halting the machine.
729 Your processor must be a Pentium or newer to support this - check the
730 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
731 have a design flaw which leads to false MCE events - hence MCE is
732 disabled on all P5 processors, unless explicitly enabled with "mce"
733 as a boot argument. Similarly, if MCE is built in and creates a
734 problem on some new non-standard machine, you can boot with "nomce"
735 to disable it. MCE support simply ignores non-MCE processors like
736 the 386 and 486, so nearly everyone can say Y here.
740 prompt "Intel MCE features"
741 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
743 Additional support for intel specific MCE features such as
748 prompt "AMD MCE features"
749 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
751 Additional support for AMD specific MCE features such as
752 the DRAM Error Threshold.
754 config X86_MCE_THRESHOLD
755 depends on X86_MCE_AMD || X86_MCE_INTEL
759 config X86_MCE_NONFATAL
760 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
761 depends on X86_32 && X86_MCE
763 Enabling this feature starts a timer that triggers every 5 seconds which
764 will look at the machine check registers to see if anything happened.
765 Non-fatal problems automatically get corrected (but still logged).
766 Disable this if you don't want to see these messages.
767 Seeing the messages this option prints out may be indicative of dying
768 or out-of-spec (ie, overclocked) hardware.
769 This option only does something on certain CPUs.
770 (AMD Athlon/Duron and Intel Pentium 4)
772 config X86_MCE_P4THERMAL
773 bool "check for P4 thermal throttling interrupt."
774 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
776 Enabling this feature will cause a message to be printed when the P4
777 enters thermal throttling.
780 bool "Enable VM86 support" if EMBEDDED
784 This option is required by programs like DOSEMU to run 16-bit legacy
785 code on X86 processors. It also may be needed by software like
786 XFree86 to initialize some video cards via BIOS. Disabling this
787 option saves about 6k.
790 tristate "Toshiba Laptop support"
793 This adds a driver to safely access the System Management Mode of
794 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
795 not work on models with a Phoenix BIOS. The System Management Mode
796 is used to set the BIOS and power saving options on Toshiba portables.
798 For information on utilities to make use of this driver see the
799 Toshiba Linux utilities web site at:
800 <http://www.buzzard.org.uk/toshiba/>.
802 Say Y if you intend to run this kernel on a Toshiba portable.
806 tristate "Dell laptop support"
808 This adds a driver to safely access the System Management Mode
809 of the CPU on the Dell Inspiron 8000. The System Management Mode
810 is used to read cpu temperature and cooling fan status and to
811 control the fans on the I8K portables.
813 This driver has been tested only on the Inspiron 8000 but it may
814 also work with other Dell laptops. You can force loading on other
815 models by passing the parameter `force=1' to the module. Use at
818 For information on utilities to make use of this driver see the
819 I8K Linux utilities web site at:
820 <http://people.debian.org/~dz/i8k/>
822 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
825 config X86_REBOOTFIXUPS
826 bool "Enable X86 board specific fixups for reboot"
829 This enables chipset and/or board specific fixups to be done
830 in order to get reboot to work correctly. This is only needed on
831 some combinations of hardware and BIOS. The symptom, for which
832 this config is intended, is when reboot ends with a stalled/hung
835 Currently, the only fixup is for the Geode machines using
836 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
838 Say Y if you want to enable the fixup. Currently, it's safe to
839 enable this option even if you don't need it.
843 tristate "/dev/cpu/microcode - microcode support"
846 If you say Y here, you will be able to update the microcode on
847 certain Intel and AMD processors. The Intel support is for the
848 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
849 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
850 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
851 You will obviously need the actual microcode binary data itself
852 which is not shipped with the Linux kernel.
854 This option selects the general module only, you need to select
855 at least one vendor specific module as well.
857 To compile this driver as a module, choose M here: the
858 module will be called microcode.
860 config MICROCODE_INTEL
861 bool "Intel microcode patch loading support"
866 This options enables microcode patch loading support for Intel
869 For latest news and information on obtaining all the required
870 Intel ingredients for this driver, check:
871 <http://www.urbanmyth.org/microcode/>.
874 bool "AMD microcode patch loading support"
878 If you select this option, microcode patch loading support for AMD
879 processors will be enabled.
881 config MICROCODE_OLD_INTERFACE
886 tristate "/dev/cpu/*/msr - Model-specific register support"
888 This device gives privileged processes access to the x86
889 Model-Specific Registers (MSRs). It is a character device with
890 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
891 MSR accesses are directed to a specific CPU on multi-processor
895 tristate "/dev/cpu/*/cpuid - CPU information support"
897 This device gives processes access to the x86 CPUID instruction to
898 be executed on a specific processor. It is a character device
899 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
903 prompt "High Memory Support"
904 default HIGHMEM4G if !X86_NUMAQ
905 default HIGHMEM64G if X86_NUMAQ
910 depends on !X86_NUMAQ
912 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
913 However, the address space of 32-bit x86 processors is only 4
914 Gigabytes large. That means that, if you have a large amount of
915 physical memory, not all of it can be "permanently mapped" by the
916 kernel. The physical memory that's not permanently mapped is called
919 If you are compiling a kernel which will never run on a machine with
920 more than 1 Gigabyte total physical RAM, answer "off" here (default
921 choice and suitable for most users). This will result in a "3GB/1GB"
922 split: 3GB are mapped so that each process sees a 3GB virtual memory
923 space and the remaining part of the 4GB virtual memory space is used
924 by the kernel to permanently map as much physical memory as
927 If the machine has between 1 and 4 Gigabytes physical RAM, then
930 If more than 4 Gigabytes is used then answer "64GB" here. This
931 selection turns Intel PAE (Physical Address Extension) mode on.
932 PAE implements 3-level paging on IA32 processors. PAE is fully
933 supported by Linux, PAE mode is implemented on all recent Intel
934 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
935 then the kernel will not boot on CPUs that don't support PAE!
937 The actual amount of total physical memory will either be
938 auto detected or can be forced by using a kernel command line option
939 such as "mem=256M". (Try "man bootparam" or see the documentation of
940 your boot loader (lilo or loadlin) about how to pass options to the
941 kernel at boot time.)
943 If unsure, say "off".
947 depends on !X86_NUMAQ
949 Select this if you have a 32-bit processor and between 1 and 4
950 gigabytes of physical RAM.
954 depends on !M386 && !M486
957 Select this if you have a 32-bit processor and more than 4
958 gigabytes of physical RAM.
963 depends on EXPERIMENTAL
964 prompt "Memory split" if EMBEDDED
968 Select the desired split between kernel and user memory.
970 If the address range available to the kernel is less than the
971 physical memory installed, the remaining memory will be available
972 as "high memory". Accessing high memory is a little more costly
973 than low memory, as it needs to be mapped into the kernel first.
974 Note that increasing the kernel address space limits the range
975 available to user programs, making the address space there
976 tighter. Selecting anything other than the default 3G/1G split
977 will also likely make your kernel incompatible with binary-only
980 If you are not absolutely sure what you are doing, leave this
984 bool "3G/1G user/kernel split"
985 config VMSPLIT_3G_OPT
987 bool "3G/1G user/kernel split (for full 1G low memory)"
989 bool "2G/2G user/kernel split"
990 config VMSPLIT_2G_OPT
992 bool "2G/2G user/kernel split (for full 2G low memory)"
994 bool "1G/3G user/kernel split"
999 default 0xB0000000 if VMSPLIT_3G_OPT
1000 default 0x80000000 if VMSPLIT_2G
1001 default 0x78000000 if VMSPLIT_2G_OPT
1002 default 0x40000000 if VMSPLIT_1G
1008 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1011 bool "PAE (Physical Address Extension) Support"
1012 depends on X86_32 && !HIGHMEM4G
1014 PAE is required for NX support, and furthermore enables
1015 larger swapspace support for non-overcommit purposes. It
1016 has the cost of more pagetable lookup overhead, and also
1017 consumes more pagetable space per process.
1019 config ARCH_PHYS_ADDR_T_64BIT
1020 def_bool X86_64 || X86_PAE
1022 config DIRECT_GBPAGES
1023 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1027 Allow the kernel linear mapping to use 1GB pages on CPUs that
1028 support it. This can improve the kernel's performance a tiny bit by
1029 reducing TLB pressure. If in doubt, say "Y".
1031 # Common NUMA Features
1033 bool "Numa Memory Allocation and Scheduler Support"
1035 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1037 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1039 Enable NUMA (Non Uniform Memory Access) support.
1041 The kernel will try to allocate memory used by a CPU on the
1042 local memory controller of the CPU and add some more
1043 NUMA awareness to the kernel.
1045 For 64-bit this is recommended if the system is Intel Core i7
1046 (or later), AMD Opteron, or EM64T NUMA.
1048 For 32-bit this is only needed on (rare) 32-bit-only platforms
1049 that support NUMA topologies, such as NUMAQ / Summit, or if you
1050 boot a 32-bit kernel on a 64-bit NUMA platform.
1052 Otherwise, you should say N.
1054 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1055 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1059 prompt "Old style AMD Opteron NUMA detection"
1060 depends on X86_64 && NUMA && PCI
1062 Enable K8 NUMA node topology detection. You should say Y here if
1063 you have a multi processor AMD K8 system. This uses an old
1064 method to read the NUMA configuration directly from the builtin
1065 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1066 instead, which also takes priority if both are compiled in.
1068 config X86_64_ACPI_NUMA
1070 prompt "ACPI NUMA detection"
1071 depends on X86_64 && NUMA && ACPI && PCI
1074 Enable ACPI SRAT based node topology detection.
1076 # Some NUMA nodes have memory ranges that span
1077 # other nodes. Even though a pfn is valid and
1078 # between a node's start and end pfns, it may not
1079 # reside on that node. See memmap_init_zone()
1081 config NODES_SPAN_OTHER_NODES
1083 depends on X86_64_ACPI_NUMA
1086 bool "NUMA emulation"
1087 depends on X86_64 && NUMA
1089 Enable NUMA emulation. A flat machine will be split
1090 into virtual nodes when booted with "numa=fake=N", where N is the
1091 number of nodes. This is only useful for debugging.
1094 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1096 default "9" if MAXSMP
1097 default "6" if X86_64
1098 default "4" if X86_NUMAQ
1100 depends on NEED_MULTIPLE_NODES
1102 Specify the maximum number of NUMA Nodes available on the target
1103 system. Increases memory reserved to accomodate various tables.
1105 config HAVE_ARCH_BOOTMEM_NODE
1107 depends on X86_32 && NUMA
1109 config ARCH_HAVE_MEMORY_PRESENT
1111 depends on X86_32 && DISCONTIGMEM
1113 config NEED_NODE_MEMMAP_SIZE
1115 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1117 config HAVE_ARCH_ALLOC_REMAP
1119 depends on X86_32 && NUMA
1121 config ARCH_FLATMEM_ENABLE
1123 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1125 config ARCH_DISCONTIGMEM_ENABLE
1127 depends on NUMA && X86_32
1129 config ARCH_DISCONTIGMEM_DEFAULT
1131 depends on NUMA && X86_32
1133 config ARCH_SPARSEMEM_DEFAULT
1137 config ARCH_SPARSEMEM_ENABLE
1139 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1140 select SPARSEMEM_STATIC if X86_32
1141 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1143 config ARCH_SELECT_MEMORY_MODEL
1145 depends on ARCH_SPARSEMEM_ENABLE
1147 config ARCH_MEMORY_PROBE
1149 depends on MEMORY_HOTPLUG
1154 bool "Allocate 3rd-level pagetables from highmem"
1155 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1157 The VM uses one page table entry for each page of physical memory.
1158 For systems with a lot of RAM, this can be wasteful of precious
1159 low memory. Setting this option will put user-space page table
1160 entries in high memory.
1162 config X86_CHECK_BIOS_CORRUPTION
1163 bool "Check for low memory corruption"
1165 Periodically check for memory corruption in low memory, which
1166 is suspected to be caused by BIOS. Even when enabled in the
1167 configuration, it is disabled at runtime. Enable it by
1168 setting "memory_corruption_check=1" on the kernel command
1169 line. By default it scans the low 64k of memory every 60
1170 seconds; see the memory_corruption_check_size and
1171 memory_corruption_check_period parameters in
1172 Documentation/kernel-parameters.txt to adjust this.
1174 When enabled with the default parameters, this option has
1175 almost no overhead, as it reserves a relatively small amount
1176 of memory and scans it infrequently. It both detects corruption
1177 and prevents it from affecting the running system.
1179 It is, however, intended as a diagnostic tool; if repeatable
1180 BIOS-originated corruption always affects the same memory,
1181 you can use memmap= to prevent the kernel from using that
1184 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1185 bool "Set the default setting of memory_corruption_check"
1186 depends on X86_CHECK_BIOS_CORRUPTION
1189 Set whether the default state of memory_corruption_check is
1192 config X86_RESERVE_LOW_64K
1193 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1196 Reserve the first 64K of physical RAM on BIOSes that are known
1197 to potentially corrupt that memory range. A numbers of BIOSes are
1198 known to utilize this area during suspend/resume, so it must not
1199 be used by the kernel.
1201 Set this to N if you are absolutely sure that you trust the BIOS
1202 to get all its memory reservations and usages right.
1204 If you have doubts about the BIOS (e.g. suspend/resume does not
1205 work or there's kernel crashes after certain hardware hotplug
1206 events) and it's not AMI or Phoenix, then you might want to enable
1207 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1208 corruption patterns.
1212 config MATH_EMULATION
1214 prompt "Math emulation" if X86_32
1216 Linux can emulate a math coprocessor (used for floating point
1217 operations) if you don't have one. 486DX and Pentium processors have
1218 a math coprocessor built in, 486SX and 386 do not, unless you added
1219 a 487DX or 387, respectively. (The messages during boot time can
1220 give you some hints here ["man dmesg"].) Everyone needs either a
1221 coprocessor or this emulation.
1223 If you don't have a math coprocessor, you need to say Y here; if you
1224 say Y here even though you have a coprocessor, the coprocessor will
1225 be used nevertheless. (This behavior can be changed with the kernel
1226 command line option "no387", which comes handy if your coprocessor
1227 is broken. Try "man bootparam" or see the documentation of your boot
1228 loader (lilo or loadlin) about how to pass options to the kernel at
1229 boot time.) This means that it is a good idea to say Y here if you
1230 intend to use this kernel on different machines.
1232 More information about the internals of the Linux math coprocessor
1233 emulation can be found in <file:arch/x86/math-emu/README>.
1235 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1236 kernel, it won't hurt.
1239 bool "MTRR (Memory Type Range Register) support"
1241 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1242 the Memory Type Range Registers (MTRRs) may be used to control
1243 processor access to memory ranges. This is most useful if you have
1244 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1245 allows bus write transfers to be combined into a larger transfer
1246 before bursting over the PCI/AGP bus. This can increase performance
1247 of image write operations 2.5 times or more. Saying Y here creates a
1248 /proc/mtrr file which may be used to manipulate your processor's
1249 MTRRs. Typically the X server should use this.
1251 This code has a reasonably generic interface so that similar
1252 control registers on other processors can be easily supported
1255 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1256 Registers (ARRs) which provide a similar functionality to MTRRs. For
1257 these, the ARRs are used to emulate the MTRRs.
1258 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1259 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1260 write-combining. All of these processors are supported by this code
1261 and it makes sense to say Y here if you have one of them.
1263 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1264 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1265 can lead to all sorts of problems, so it's good to say Y here.
1267 You can safely say Y even if your machine doesn't have MTRRs, you'll
1268 just add about 9 KB to your kernel.
1270 See <file:Documentation/x86/mtrr.txt> for more information.
1272 config MTRR_SANITIZER
1274 prompt "MTRR cleanup support"
1277 Convert MTRR layout from continuous to discrete, so X drivers can
1278 add writeback entries.
1280 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1281 The largest mtrr entry size for a continous block can be set with
1286 config MTRR_SANITIZER_ENABLE_DEFAULT
1287 int "MTRR cleanup enable value (0-1)"
1290 depends on MTRR_SANITIZER
1292 Enable mtrr cleanup default value
1294 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1295 int "MTRR cleanup spare reg num (0-7)"
1298 depends on MTRR_SANITIZER
1300 mtrr cleanup spare entries default, it can be changed via
1301 mtrr_spare_reg_nr=N on the kernel command line.
1305 prompt "x86 PAT support"
1308 Use PAT attributes to setup page level cache control.
1310 PATs are the modern equivalents of MTRRs and are much more
1311 flexible than MTRRs.
1313 Say N here if you see bootup problems (boot crash, boot hang,
1314 spontaneous reboots) or a non-working video driver.
1319 bool "EFI runtime service support"
1322 This enables the kernel to use EFI runtime services that are
1323 available (such as the EFI variable services).
1325 This option is only useful on systems that have EFI firmware.
1326 In addition, you should use the latest ELILO loader available
1327 at <http://elilo.sourceforge.net> in order to take advantage
1328 of EFI runtime services. However, even with this option, the
1329 resultant kernel should continue to boot on existing non-EFI
1334 prompt "Enable seccomp to safely compute untrusted bytecode"
1336 This kernel feature is useful for number crunching applications
1337 that may need to compute untrusted bytecode during their
1338 execution. By using pipes or other transports made available to
1339 the process as file descriptors supporting the read/write
1340 syscalls, it's possible to isolate those applications in
1341 their own address space using seccomp. Once seccomp is
1342 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1343 and the task is only allowed to execute a few safe syscalls
1344 defined by each seccomp mode.
1346 If unsure, say Y. Only embedded should say N here.
1348 config CC_STACKPROTECTOR
1349 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1350 depends on X86_64 && EXPERIMENTAL && BROKEN
1352 This option turns on the -fstack-protector GCC feature. This
1353 feature puts, at the beginning of critical functions, a canary
1354 value on the stack just before the return address, and validates
1355 the value just before actually returning. Stack based buffer
1356 overflows (that need to overwrite this return address) now also
1357 overwrite the canary, which gets detected and the attack is then
1358 neutralized via a kernel panic.
1360 This feature requires gcc version 4.2 or above, or a distribution
1361 gcc with the feature backported. Older versions are automatically
1362 detected and for those versions, this configuration option is ignored.
1364 config CC_STACKPROTECTOR_ALL
1365 bool "Use stack-protector for all functions"
1366 depends on CC_STACKPROTECTOR
1368 Normally, GCC only inserts the canary value protection for
1369 functions that use large-ish on-stack buffers. By enabling
1370 this option, GCC will be asked to do this for ALL functions.
1372 source kernel/Kconfig.hz
1375 bool "kexec system call"
1376 depends on X86_BIOS_REBOOT
1378 kexec is a system call that implements the ability to shutdown your
1379 current kernel, and to start another kernel. It is like a reboot
1380 but it is independent of the system firmware. And like a reboot
1381 you can start any kernel with it, not just Linux.
1383 The name comes from the similarity to the exec system call.
1385 It is an ongoing process to be certain the hardware in a machine
1386 is properly shutdown, so do not be surprised if this code does not
1387 initially work for you. It may help to enable device hotplugging
1388 support. As of this writing the exact hardware interface is
1389 strongly in flux, so no good recommendation can be made.
1392 bool "kernel crash dumps"
1393 depends on X86_64 || (X86_32 && HIGHMEM)
1395 Generate crash dump after being started by kexec.
1396 This should be normally only set in special crash dump kernels
1397 which are loaded in the main kernel with kexec-tools into
1398 a specially reserved region and then later executed after
1399 a crash by kdump/kexec. The crash dump kernel must be compiled
1400 to a memory address not used by the main kernel or BIOS using
1401 PHYSICAL_START, or it must be built as a relocatable image
1402 (CONFIG_RELOCATABLE=y).
1403 For more details see Documentation/kdump/kdump.txt
1406 bool "kexec jump (EXPERIMENTAL)"
1407 depends on EXPERIMENTAL
1408 depends on KEXEC && HIBERNATION && X86_32
1410 Jump between original kernel and kexeced kernel and invoke
1411 code in physical address mode via KEXEC
1413 config PHYSICAL_START
1414 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1415 default "0x1000000" if X86_NUMAQ
1416 default "0x200000" if X86_64
1419 This gives the physical address where the kernel is loaded.
1421 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1422 bzImage will decompress itself to above physical address and
1423 run from there. Otherwise, bzImage will run from the address where
1424 it has been loaded by the boot loader and will ignore above physical
1427 In normal kdump cases one does not have to set/change this option
1428 as now bzImage can be compiled as a completely relocatable image
1429 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1430 address. This option is mainly useful for the folks who don't want
1431 to use a bzImage for capturing the crash dump and want to use a
1432 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1433 to be specifically compiled to run from a specific memory area
1434 (normally a reserved region) and this option comes handy.
1436 So if you are using bzImage for capturing the crash dump, leave
1437 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1438 Otherwise if you plan to use vmlinux for capturing the crash dump
1439 change this value to start of the reserved region (Typically 16MB
1440 0x1000000). In other words, it can be set based on the "X" value as
1441 specified in the "crashkernel=YM@XM" command line boot parameter
1442 passed to the panic-ed kernel. Typically this parameter is set as
1443 crashkernel=64M@16M. Please take a look at
1444 Documentation/kdump/kdump.txt for more details about crash dumps.
1446 Usage of bzImage for capturing the crash dump is recommended as
1447 one does not have to build two kernels. Same kernel can be used
1448 as production kernel and capture kernel. Above option should have
1449 gone away after relocatable bzImage support is introduced. But it
1450 is present because there are users out there who continue to use
1451 vmlinux for dump capture. This option should go away down the
1454 Don't change this unless you know what you are doing.
1457 bool "Build a relocatable kernel (EXPERIMENTAL)"
1458 depends on EXPERIMENTAL
1460 This builds a kernel image that retains relocation information
1461 so it can be loaded someplace besides the default 1MB.
1462 The relocations tend to make the kernel binary about 10% larger,
1463 but are discarded at runtime.
1465 One use is for the kexec on panic case where the recovery kernel
1466 must live at a different physical address than the primary
1469 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1470 it has been loaded at and the compile time physical address
1471 (CONFIG_PHYSICAL_START) is ignored.
1473 config PHYSICAL_ALIGN
1475 prompt "Alignment value to which kernel should be aligned" if X86_32
1476 default "0x100000" if X86_32
1477 default "0x200000" if X86_64
1478 range 0x2000 0x400000
1480 This value puts the alignment restrictions on physical address
1481 where kernel is loaded and run from. Kernel is compiled for an
1482 address which meets above alignment restriction.
1484 If bootloader loads the kernel at a non-aligned address and
1485 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1486 address aligned to above value and run from there.
1488 If bootloader loads the kernel at a non-aligned address and
1489 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1490 load address and decompress itself to the address it has been
1491 compiled for and run from there. The address for which kernel is
1492 compiled already meets above alignment restrictions. Hence the
1493 end result is that kernel runs from a physical address meeting
1494 above alignment restrictions.
1496 Don't change this unless you know what you are doing.
1499 bool "Support for hot-pluggable CPUs"
1500 depends on SMP && HOTPLUG && !X86_VOYAGER
1502 Say Y here to allow turning CPUs off and on. CPUs can be
1503 controlled through /sys/devices/system/cpu.
1504 ( Note: power management support will enable this option
1505 automatically on SMP systems. )
1506 Say N if you want to disable CPU hotplug.
1510 prompt "Compat VDSO support"
1511 depends on X86_32 || IA32_EMULATION
1513 Map the 32-bit VDSO to the predictable old-style address too.
1515 Say N here if you are running a sufficiently recent glibc
1516 version (2.3.3 or later), to remove the high-mapped
1517 VDSO mapping and to exclusively use the randomized VDSO.
1522 bool "Built-in kernel command line"
1525 Allow for specifying boot arguments to the kernel at
1526 build time. On some systems (e.g. embedded ones), it is
1527 necessary or convenient to provide some or all of the
1528 kernel boot arguments with the kernel itself (that is,
1529 to not rely on the boot loader to provide them.)
1531 To compile command line arguments into the kernel,
1532 set this option to 'Y', then fill in the
1533 the boot arguments in CONFIG_CMDLINE.
1535 Systems with fully functional boot loaders (i.e. non-embedded)
1536 should leave this option set to 'N'.
1539 string "Built-in kernel command string"
1540 depends on CMDLINE_BOOL
1543 Enter arguments here that should be compiled into the kernel
1544 image and used at boot time. If the boot loader provides a
1545 command line at boot time, it is appended to this string to
1546 form the full kernel command line, when the system boots.
1548 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1549 change this behavior.
1551 In most cases, the command line (whether built-in or provided
1552 by the boot loader) should specify the device for the root
1555 config CMDLINE_OVERRIDE
1556 bool "Built-in command line overrides boot loader arguments"
1558 depends on CMDLINE_BOOL
1560 Set this option to 'Y' to have the kernel ignore the boot loader
1561 command line, and use ONLY the built-in command line.
1563 This is used to work around broken boot loaders. This should
1564 be set to 'N' under normal conditions.
1568 config ARCH_ENABLE_MEMORY_HOTPLUG
1570 depends on X86_64 || (X86_32 && HIGHMEM)
1572 config ARCH_ENABLE_MEMORY_HOTREMOVE
1574 depends on MEMORY_HOTPLUG
1576 config HAVE_ARCH_EARLY_PFN_TO_NID
1580 menu "Power management and ACPI options"
1581 depends on !X86_VOYAGER
1583 config ARCH_HIBERNATION_HEADER
1585 depends on X86_64 && HIBERNATION
1587 source "kernel/power/Kconfig"
1589 source "drivers/acpi/Kconfig"
1594 depends on APM || APM_MODULE
1597 tristate "APM (Advanced Power Management) BIOS support"
1598 depends on X86_32 && PM_SLEEP
1600 APM is a BIOS specification for saving power using several different
1601 techniques. This is mostly useful for battery powered laptops with
1602 APM compliant BIOSes. If you say Y here, the system time will be
1603 reset after a RESUME operation, the /proc/apm device will provide
1604 battery status information, and user-space programs will receive
1605 notification of APM "events" (e.g. battery status change).
1607 If you select "Y" here, you can disable actual use of the APM
1608 BIOS by passing the "apm=off" option to the kernel at boot time.
1610 Note that the APM support is almost completely disabled for
1611 machines with more than one CPU.
1613 In order to use APM, you will need supporting software. For location
1614 and more information, read <file:Documentation/power/pm.txt> and the
1615 Battery Powered Linux mini-HOWTO, available from
1616 <http://www.tldp.org/docs.html#howto>.
1618 This driver does not spin down disk drives (see the hdparm(8)
1619 manpage ("man 8 hdparm") for that), and it doesn't turn off
1620 VESA-compliant "green" monitors.
1622 This driver does not support the TI 4000M TravelMate and the ACER
1623 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1624 desktop machines also don't have compliant BIOSes, and this driver
1625 may cause those machines to panic during the boot phase.
1627 Generally, if you don't have a battery in your machine, there isn't
1628 much point in using this driver and you should say N. If you get
1629 random kernel OOPSes or reboots that don't seem to be related to
1630 anything, try disabling/enabling this option (or disabling/enabling
1633 Some other things you should try when experiencing seemingly random,
1636 1) make sure that you have enough swap space and that it is
1638 2) pass the "no-hlt" option to the kernel
1639 3) switch on floating point emulation in the kernel and pass
1640 the "no387" option to the kernel
1641 4) pass the "floppy=nodma" option to the kernel
1642 5) pass the "mem=4M" option to the kernel (thereby disabling
1643 all but the first 4 MB of RAM)
1644 6) make sure that the CPU is not over clocked.
1645 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1646 8) disable the cache from your BIOS settings
1647 9) install a fan for the video card or exchange video RAM
1648 10) install a better fan for the CPU
1649 11) exchange RAM chips
1650 12) exchange the motherboard.
1652 To compile this driver as a module, choose M here: the
1653 module will be called apm.
1657 config APM_IGNORE_USER_SUSPEND
1658 bool "Ignore USER SUSPEND"
1660 This option will ignore USER SUSPEND requests. On machines with a
1661 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1662 series notebooks, it is necessary to say Y because of a BIOS bug.
1664 config APM_DO_ENABLE
1665 bool "Enable PM at boot time"
1667 Enable APM features at boot time. From page 36 of the APM BIOS
1668 specification: "When disabled, the APM BIOS does not automatically
1669 power manage devices, enter the Standby State, enter the Suspend
1670 State, or take power saving steps in response to CPU Idle calls."
1671 This driver will make CPU Idle calls when Linux is idle (unless this
1672 feature is turned off -- see "Do CPU IDLE calls", below). This
1673 should always save battery power, but more complicated APM features
1674 will be dependent on your BIOS implementation. You may need to turn
1675 this option off if your computer hangs at boot time when using APM
1676 support, or if it beeps continuously instead of suspending. Turn
1677 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1678 T400CDT. This is off by default since most machines do fine without
1682 bool "Make CPU Idle calls when idle"
1684 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1685 On some machines, this can activate improved power savings, such as
1686 a slowed CPU clock rate, when the machine is idle. These idle calls
1687 are made after the idle loop has run for some length of time (e.g.,
1688 333 mS). On some machines, this will cause a hang at boot time or
1689 whenever the CPU becomes idle. (On machines with more than one CPU,
1690 this option does nothing.)
1692 config APM_DISPLAY_BLANK
1693 bool "Enable console blanking using APM"
1695 Enable console blanking using the APM. Some laptops can use this to
1696 turn off the LCD backlight when the screen blanker of the Linux
1697 virtual console blanks the screen. Note that this is only used by
1698 the virtual console screen blanker, and won't turn off the backlight
1699 when using the X Window system. This also doesn't have anything to
1700 do with your VESA-compliant power-saving monitor. Further, this
1701 option doesn't work for all laptops -- it might not turn off your
1702 backlight at all, or it might print a lot of errors to the console,
1703 especially if you are using gpm.
1705 config APM_ALLOW_INTS
1706 bool "Allow interrupts during APM BIOS calls"
1708 Normally we disable external interrupts while we are making calls to
1709 the APM BIOS as a measure to lessen the effects of a badly behaving
1710 BIOS implementation. The BIOS should reenable interrupts if it
1711 needs to. Unfortunately, some BIOSes do not -- especially those in
1712 many of the newer IBM Thinkpads. If you experience hangs when you
1713 suspend, try setting this to Y. Otherwise, say N.
1717 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1719 source "drivers/cpuidle/Kconfig"
1721 source "drivers/idle/Kconfig"
1726 menu "Bus options (PCI etc.)"
1731 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1733 Find out whether you have a PCI motherboard. PCI is the name of a
1734 bus system, i.e. the way the CPU talks to the other stuff inside
1735 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1736 VESA. If you have PCI, say Y, otherwise N.
1739 prompt "PCI access mode"
1740 depends on X86_32 && PCI
1743 On PCI systems, the BIOS can be used to detect the PCI devices and
1744 determine their configuration. However, some old PCI motherboards
1745 have BIOS bugs and may crash if this is done. Also, some embedded
1746 PCI-based systems don't have any BIOS at all. Linux can also try to
1747 detect the PCI hardware directly without using the BIOS.
1749 With this option, you can specify how Linux should detect the
1750 PCI devices. If you choose "BIOS", the BIOS will be used,
1751 if you choose "Direct", the BIOS won't be used, and if you
1752 choose "MMConfig", then PCI Express MMCONFIG will be used.
1753 If you choose "Any", the kernel will try MMCONFIG, then the
1754 direct access method and falls back to the BIOS if that doesn't
1755 work. If unsure, go with the default, which is "Any".
1760 config PCI_GOMMCONFIG
1777 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1779 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1782 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1786 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1790 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1797 bool "Support mmconfig PCI config space access"
1798 depends on X86_64 && PCI && ACPI
1801 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1802 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1804 DMA remapping (DMAR) devices support enables independent address
1805 translations for Direct Memory Access (DMA) from devices.
1806 These DMA remapping devices are reported via ACPI tables
1807 and include PCI device scope covered by these DMA
1810 config DMAR_DEFAULT_ON
1812 prompt "Enable DMA Remapping Devices by default"
1815 Selecting this option will enable a DMAR device at boot time if
1816 one is found. If this option is not selected, DMAR support can
1817 be enabled by passing intel_iommu=on to the kernel. It is
1818 recommended you say N here while the DMAR code remains
1823 prompt "Support for Graphics workaround"
1826 Current Graphics drivers tend to use physical address
1827 for DMA and avoid using DMA APIs. Setting this config
1828 option permits the IOMMU driver to set a unity map for
1829 all the OS-visible memory. Hence the driver can continue
1830 to use physical addresses for DMA.
1832 config DMAR_FLOPPY_WA
1836 Floppy disk drivers are know to bypass DMA API calls
1837 thereby failing to work when IOMMU is enabled. This
1838 workaround will setup a 1:1 mapping for the first
1839 16M to make floppy (an ISA device) work.
1842 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1843 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1845 Supports Interrupt remapping for IO-APIC and MSI devices.
1846 To use x2apic mode in the CPU's which support x2APIC enhancements or
1847 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1849 source "drivers/pci/pcie/Kconfig"
1851 source "drivers/pci/Kconfig"
1853 # x86_64 have no ISA slots, but do have ISA-style DMA.
1861 depends on !X86_VOYAGER
1863 Find out whether you have ISA slots on your motherboard. ISA is the
1864 name of a bus system, i.e. the way the CPU talks to the other stuff
1865 inside your box. Other bus systems are PCI, EISA, MicroChannel
1866 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1867 newer boards don't support it. If you have ISA, say Y, otherwise N.
1873 The Extended Industry Standard Architecture (EISA) bus was
1874 developed as an open alternative to the IBM MicroChannel bus.
1876 The EISA bus provided some of the features of the IBM MicroChannel
1877 bus while maintaining backward compatibility with cards made for
1878 the older ISA bus. The EISA bus saw limited use between 1988 and
1879 1995 when it was made obsolete by the PCI bus.
1881 Say Y here if you are building a kernel for an EISA-based machine.
1885 source "drivers/eisa/Kconfig"
1888 bool "MCA support" if !X86_VOYAGER
1889 default y if X86_VOYAGER
1891 MicroChannel Architecture is found in some IBM PS/2 machines and
1892 laptops. It is a bus system similar to PCI or ISA. See
1893 <file:Documentation/mca.txt> (and especially the web page given
1894 there) before attempting to build an MCA bus kernel.
1896 source "drivers/mca/Kconfig"
1899 tristate "NatSemi SCx200 support"
1900 depends on !X86_VOYAGER
1902 This provides basic support for National Semiconductor's
1903 (now AMD's) Geode processors. The driver probes for the
1904 PCI-IDs of several on-chip devices, so its a good dependency
1905 for other scx200_* drivers.
1907 If compiled as a module, the driver is named scx200.
1909 config SCx200HR_TIMER
1910 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1911 depends on SCx200 && GENERIC_TIME
1914 This driver provides a clocksource built upon the on-chip
1915 27MHz high-resolution timer. Its also a workaround for
1916 NSC Geode SC-1100's buggy TSC, which loses time when the
1917 processor goes idle (as is done by the scheduler). The
1918 other workaround is idle=poll boot option.
1920 config GEODE_MFGPT_TIMER
1922 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1923 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1925 This driver provides a clock event source based on the MFGPT
1926 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1927 MFGPTs have a better resolution and max interval than the
1928 generic PIT, and are suitable for use as high-res timers.
1931 bool "One Laptop Per Child support"
1934 Add support for detecting the unique features of the OLPC
1941 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1943 source "drivers/pcmcia/Kconfig"
1945 source "drivers/pci/hotplug/Kconfig"
1950 menu "Executable file formats / Emulations"
1952 source "fs/Kconfig.binfmt"
1954 config IA32_EMULATION
1955 bool "IA32 Emulation"
1957 select COMPAT_BINFMT_ELF
1959 Include code to run 32-bit programs under a 64-bit kernel. You should
1960 likely turn this on, unless you're 100% sure that you don't have any
1961 32-bit programs left.
1964 tristate "IA32 a.out support"
1965 depends on IA32_EMULATION
1967 Support old a.out binaries in the 32bit emulation.
1971 depends on IA32_EMULATION
1973 config COMPAT_FOR_U64_ALIGNMENT
1977 config SYSVIPC_COMPAT
1979 depends on COMPAT && SYSVIPC
1984 config HAVE_ATOMIC_IOMAP
1988 source "net/Kconfig"
1990 source "drivers/Kconfig"
1992 source "drivers/firmware/Kconfig"
1996 source "arch/x86/Kconfig.debug"
1998 source "security/Kconfig"
2000 source "crypto/Kconfig"
2002 source "arch/x86/kvm/Kconfig"
2004 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob