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
22 select HAVE_UNSTABLE_SCHED_CLOCK
25 select HAVE_IOREMAP_PROT
27 select ARCH_WANT_OPTIONAL_GPIOLIB
28 select HAVE_KRETPROBES
29 select HAVE_DYNAMIC_FTRACE
31 select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
32 select HAVE_ARCH_KGDB if !X86_VOYAGER
33 select HAVE_ARCH_TRACEHOOK
34 select HAVE_GENERIC_DMA_COHERENT if X86_32
35 select HAVE_EFFICIENT_UNALIGNED_ACCESS
39 default "arch/x86/configs/i386_defconfig" if X86_32
40 default "arch/x86/configs/x86_64_defconfig" if X86_64
43 config GENERIC_LOCKBREAK
49 config GENERIC_CMOS_UPDATE
52 config CLOCKSOURCE_WATCHDOG
55 config GENERIC_CLOCKEVENTS
58 config GENERIC_CLOCKEVENTS_BROADCAST
60 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
62 config LOCKDEP_SUPPORT
65 config STACKTRACE_SUPPORT
68 config HAVE_LATENCYTOP_SUPPORT
71 config FAST_CMPXCHG_LOCAL
84 config GENERIC_ISA_DMA
94 config GENERIC_HWEIGHT
100 config ARCH_MAY_HAVE_PC_FDC
103 config RWSEM_GENERIC_SPINLOCK
106 config RWSEM_XCHGADD_ALGORITHM
109 config ARCH_HAS_ILOG2_U32
112 config ARCH_HAS_ILOG2_U64
115 config ARCH_HAS_CPU_IDLE_WAIT
118 config GENERIC_CALIBRATE_DELAY
121 config GENERIC_TIME_VSYSCALL
125 config ARCH_HAS_CPU_RELAX
128 config ARCH_HAS_CACHE_LINE_SIZE
131 config HAVE_SETUP_PER_CPU_AREA
132 def_bool X86_64_SMP || (X86_SMP && !X86_VOYAGER)
134 config HAVE_CPUMASK_OF_CPU_MAP
137 config ARCH_HIBERNATION_POSSIBLE
139 depends on !SMP || !X86_VOYAGER
141 config ARCH_SUSPEND_POSSIBLE
143 depends on !X86_VOYAGER
149 config ARCH_POPULATES_NODE_MAP
156 config ARCH_SUPPORTS_OPTIMIZED_INLINING
159 # Use the generic interrupt handling code in kernel/irq/:
160 config GENERIC_HARDIRQS
164 config GENERIC_IRQ_PROBE
168 config GENERIC_PENDING_IRQ
170 depends on GENERIC_HARDIRQS && SMP
175 depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
176 select USE_GENERIC_SMP_HELPERS
181 depends on X86_32 && SMP
185 depends on X86_64 && SMP
190 depends on (X86_32 && !X86_VOYAGER) || X86_64
193 config X86_BIOS_REBOOT
195 depends on !X86_VOYAGER
198 config X86_TRAMPOLINE
200 depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
205 source "init/Kconfig"
207 menu "Processor type and features"
209 source "kernel/time/Kconfig"
212 bool "Symmetric multi-processing support"
214 This enables support for systems with more than one CPU. If you have
215 a system with only one CPU, like most personal computers, say N. If
216 you have a system with more than one CPU, say Y.
218 If you say N here, the kernel will run on single and multiprocessor
219 machines, but will use only one CPU of a multiprocessor machine. If
220 you say Y here, the kernel will run on many, but not all,
221 singleprocessor machines. On a singleprocessor machine, the kernel
222 will run faster if you say N here.
224 Note that if you say Y here and choose architecture "586" or
225 "Pentium" under "Processor family", the kernel will not work on 486
226 architectures. Similarly, multiprocessor kernels for the "PPro"
227 architecture may not work on all Pentium based boards.
229 People using multiprocessor machines who say Y here should also say
230 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
231 Management" code will be disabled if you say Y here.
233 See also <file:Documentation/i386/IO-APIC.txt>,
234 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
235 <http://www.tldp.org/docs.html#howto>.
237 If you don't know what to do here, say N.
239 config X86_FIND_SMP_CONFIG
241 depends on X86_MPPARSE || X86_VOYAGER
246 bool "Enable MPS table"
247 depends on X86_LOCAL_APIC
249 For old smp systems that do not have proper acpi support. Newer systems
250 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
256 depends on X86_LOCAL_APIC
260 prompt "Subarchitecture Type"
266 Choose this option if your computer is a standard PC or compatible.
272 Select this for an AMD Elan processor.
274 Do not use this option for K6/Athlon/Opteron processors!
276 If unsure, choose "PC-compatible" instead.
280 depends on X86_32 && (SMP || BROKEN) && !PCI
282 Voyager is an MCA-based 32-way capable SMP architecture proprietary
283 to NCR Corp. Machine classes 345x/35xx/4100/51xx are Voyager-based.
287 If you do not specifically know you have a Voyager based machine,
288 say N here, otherwise the kernel you build will not be bootable.
290 config X86_GENERICARCH
291 bool "Generic architecture"
294 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
295 subarchitectures. It is intended for a generic binary kernel.
296 if you select them all, kernel will probe it one by one. and will
302 bool "NUMAQ (IBM/Sequent)"
303 depends on SMP && X86_32 && PCI && X86_MPPARSE
306 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
307 NUMA multiquad box. This changes the way that processors are
308 bootstrapped, and uses Clustered Logical APIC addressing mode instead
309 of Flat Logical. You will need a new lynxer.elf file to flash your
310 firmware with - send email to <Martin.Bligh@us.ibm.com>.
313 bool "Summit/EXA (IBM x440)"
314 depends on X86_32 && SMP
316 This option is needed for IBM systems that use the Summit/EXA chipset.
317 In particular, it is needed for the x440.
320 bool "Support for Unisys ES7000 IA32 series"
321 depends on X86_32 && SMP
323 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
324 supposed to run on an IA32-based Unisys ES7000 system.
327 bool "Support for big SMP systems with more than 8 CPUs"
328 depends on X86_32 && SMP
330 This option is needed for the systems that have more than 8 CPUs
331 and if the system is not of any sub-arch type above.
336 bool "Support for ScaleMP vSMP"
338 depends on X86_64 && PCI
340 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
341 supposed to run on these EM64T-based machines. Only choose this option
342 if you have one of these machines.
347 bool "SGI 320/540 (Visual Workstation)"
348 depends on X86_32 && PCI && !X86_VOYAGER && X86_MPPARSE && PCI_GODIRECT
350 The SGI Visual Workstation series is an IA32-based workstation
351 based on SGI systems chips with some legacy PC hardware attached.
353 Say Y here to create a kernel to run on the SGI 320 or 540.
355 A kernel compiled for the Visual Workstation will run on general
356 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
359 bool "RDC R-321x SoC"
362 select X86_REBOOTFIXUPS
364 This option is needed for RDC R-321x system-on-chip, also known
366 If you don't have one of these chips, you should say N here.
368 config SCHED_NO_NO_OMIT_FRAME_POINTER
370 prompt "Single-depth WCHAN output"
373 Calculate simpler /proc/<PID>/wchan values. If this option
374 is disabled then wchan values will recurse back to the
375 caller function. This provides more accurate wchan values,
376 at the expense of slightly more scheduling overhead.
378 If in doubt, say "Y".
380 menuconfig PARAVIRT_GUEST
381 bool "Paravirtualized guest support"
383 Say Y here to get to see options related to running Linux under
384 various hypervisors. This option alone does not add any kernel code.
386 If you say N, all options in this submenu will be skipped and disabled.
390 source "arch/x86/xen/Kconfig"
393 bool "VMI Guest support"
396 depends on !X86_VOYAGER
398 VMI provides a paravirtualized interface to the VMware ESX server
399 (it could be used by other hypervisors in theory too, but is not
400 at the moment), by linking the kernel to a GPL-ed ROM module
401 provided by the hypervisor.
404 bool "KVM paravirtualized clock"
406 select PARAVIRT_CLOCK
407 depends on !X86_VOYAGER
409 Turning on this option will allow you to run a paravirtualized clock
410 when running over the KVM hypervisor. Instead of relying on a PIT
411 (or probably other) emulation by the underlying device model, the host
412 provides the guest with timing infrastructure such as time of day, and
416 bool "KVM Guest support"
418 depends on !X86_VOYAGER
420 This option enables various optimizations for running under the KVM
423 source "arch/x86/lguest/Kconfig"
426 bool "Enable paravirtualization code"
427 depends on !X86_VOYAGER
429 This changes the kernel so it can modify itself when it is run
430 under a hypervisor, potentially improving performance significantly
431 over full virtualization. However, when run without a hypervisor
432 the kernel is theoretically slower and slightly larger.
434 config PARAVIRT_CLOCK
440 config PARAVIRT_DEBUG
441 bool "paravirt-ops debugging"
442 depends on PARAVIRT && DEBUG_KERNEL
444 Enable to debug paravirt_ops internals. Specifically, BUG if
445 a paravirt_op is missing when it is called.
450 This option adds a kernel parameter 'memtest', which allows memtest
452 memtest=0, mean disabled; -- default
453 memtest=1, mean do 1 test pattern;
455 memtest=4, mean do 4 test patterns.
456 If you are unsure how to answer this question, answer N.
458 config X86_SUMMIT_NUMA
460 depends on X86_32 && NUMA && X86_GENERICARCH
462 config X86_CYCLONE_TIMER
464 depends on X86_GENERICARCH
466 config ES7000_CLUSTERED_APIC
468 depends on SMP && X86_ES7000 && MPENTIUMIII
470 source "arch/x86/Kconfig.cpu"
474 prompt "HPET Timer Support" if X86_32
476 Use the IA-PC HPET (High Precision Event Timer) to manage
477 time in preference to the PIT and RTC, if a HPET is
479 HPET is the next generation timer replacing legacy 8254s.
480 The HPET provides a stable time base on SMP
481 systems, unlike the TSC, but it is more expensive to access,
482 as it is off-chip. You can find the HPET spec at
483 <http://www.intel.com/hardwaredesign/hpetspec.htm>.
485 You can safely choose Y here. However, HPET will only be
486 activated if the platform and the BIOS support this feature.
487 Otherwise the 8254 will be used for timing services.
489 Choose N to continue using the legacy 8254 timer.
491 config HPET_EMULATE_RTC
493 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
495 # Mark as embedded because too many people got it wrong.
496 # The code disables itself when not needed.
499 bool "Enable DMI scanning" if EMBEDDED
501 Enabled scanning of DMI to identify machine quirks. Say Y
502 here unless you have verified that your setup is not
503 affected by entries in the DMI blacklist. Required by PNP
507 bool "GART IOMMU support" if EMBEDDED
511 depends on X86_64 && PCI
513 Support for full DMA access of devices with 32bit memory access only
514 on systems with more than 3GB. This is usually needed for USB,
515 sound, many IDE/SATA chipsets and some other devices.
516 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
517 based hardware IOMMU and a software bounce buffer based IOMMU used
518 on Intel systems and as fallback.
519 The code is only active when needed (enough memory and limited
520 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
524 bool "IBM Calgary IOMMU support"
526 depends on X86_64 && PCI && EXPERIMENTAL
528 Support for hardware IOMMUs in IBM's xSeries x366 and x460
529 systems. Needed to run systems with more than 3GB of memory
530 properly with 32-bit PCI devices that do not support DAC
531 (Double Address Cycle). Calgary also supports bus level
532 isolation, where all DMAs pass through the IOMMU. This
533 prevents them from going anywhere except their intended
534 destination. This catches hard-to-find kernel bugs and
535 mis-behaving drivers and devices that do not use the DMA-API
536 properly to set up their DMA buffers. The IOMMU can be
537 turned off at boot time with the iommu=off parameter.
538 Normally the kernel will make the right choice by itself.
541 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
543 prompt "Should Calgary be enabled by default?"
544 depends on CALGARY_IOMMU
546 Should Calgary be enabled by default? if you choose 'y', Calgary
547 will be used (if it exists). If you choose 'n', Calgary will not be
548 used even if it exists. If you choose 'n' and would like to use
549 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
553 bool "AMD IOMMU support"
556 depends on X86_64 && PCI && ACPI
558 With this option you can enable support for AMD IOMMU hardware in
559 your system. An IOMMU is a hardware component which provides
560 remapping of DMA memory accesses from devices. With an AMD IOMMU you
561 can isolate the the DMA memory of different devices and protect the
562 system from misbehaving device drivers or hardware.
564 You can find out if your system has an AMD IOMMU if you look into
565 your BIOS for an option to enable it or if you have an IVRS ACPI
568 # need this always selected by IOMMU for the VIA workaround
572 Support for software bounce buffers used on x86-64 systems
573 which don't have a hardware IOMMU (e.g. the current generation
574 of Intel's x86-64 CPUs). Using this PCI devices which can only
575 access 32-bits of memory can be used on systems with more than
576 3 GB of memory. If unsure, say Y.
579 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
582 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
583 depends on X86_64 && SMP && BROKEN
586 Configure maximum number of CPUS and NUMA Nodes for this architecture.
590 int "Maximum number of CPUs (2-512)" if !MAXSMP
593 default "4096" if MAXSMP
594 default "32" if X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000
597 This allows you to specify the maximum number of CPUs which this
598 kernel will support. The maximum supported value is 512 and the
599 minimum value which makes sense is 2.
601 This is purely to save memory - each supported CPU adds
602 approximately eight kilobytes to the kernel image.
605 bool "SMT (Hyperthreading) scheduler support"
608 SMT scheduler support improves the CPU scheduler's decision making
609 when dealing with Intel Pentium 4 chips with HyperThreading at a
610 cost of slightly increased overhead in some places. If unsure say
615 prompt "Multi-core scheduler support"
618 Multi-core scheduler support improves the CPU scheduler's decision
619 making when dealing with multi-core CPU chips at a cost of slightly
620 increased overhead in some places. If unsure say N here.
622 source "kernel/Kconfig.preempt"
625 bool "Local APIC support on uniprocessors"
626 depends on X86_32 && !SMP && !(X86_VOYAGER || X86_GENERICARCH)
628 A local APIC (Advanced Programmable Interrupt Controller) is an
629 integrated interrupt controller in the CPU. If you have a single-CPU
630 system which has a processor with a local APIC, you can say Y here to
631 enable and use it. If you say Y here even though your machine doesn't
632 have a local APIC, then the kernel will still run with no slowdown at
633 all. The local APIC supports CPU-generated self-interrupts (timer,
634 performance counters), and the NMI watchdog which detects hard
638 bool "IO-APIC support on uniprocessors"
639 depends on X86_UP_APIC
641 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
642 SMP-capable replacement for PC-style interrupt controllers. Most
643 SMP systems and many recent uniprocessor systems have one.
645 If you have a single-CPU system with an IO-APIC, you can say Y here
646 to use it. If you say Y here even though your machine doesn't have
647 an IO-APIC, then the kernel will still run with no slowdown at all.
649 config X86_LOCAL_APIC
651 depends on X86_64 || (X86_32 && (X86_UP_APIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
655 depends on X86_64 || (X86_32 && (X86_UP_IOAPIC || (SMP && !X86_VOYAGER) || X86_GENERICARCH))
657 config X86_VISWS_APIC
659 depends on X86_32 && X86_VISWS
662 bool "Machine Check Exception"
663 depends on !X86_VOYAGER
665 Machine Check Exception support allows the processor to notify the
666 kernel if it detects a problem (e.g. overheating, component failure).
667 The action the kernel takes depends on the severity of the problem,
668 ranging from a warning message on the console, to halting the machine.
669 Your processor must be a Pentium or newer to support this - check the
670 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
671 have a design flaw which leads to false MCE events - hence MCE is
672 disabled on all P5 processors, unless explicitly enabled with "mce"
673 as a boot argument. Similarly, if MCE is built in and creates a
674 problem on some new non-standard machine, you can boot with "nomce"
675 to disable it. MCE support simply ignores non-MCE processors like
676 the 386 and 486, so nearly everyone can say Y here.
680 prompt "Intel MCE features"
681 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
683 Additional support for intel specific MCE features such as
688 prompt "AMD MCE features"
689 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
691 Additional support for AMD specific MCE features such as
692 the DRAM Error Threshold.
694 config X86_MCE_NONFATAL
695 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
696 depends on X86_32 && X86_MCE
698 Enabling this feature starts a timer that triggers every 5 seconds which
699 will look at the machine check registers to see if anything happened.
700 Non-fatal problems automatically get corrected (but still logged).
701 Disable this if you don't want to see these messages.
702 Seeing the messages this option prints out may be indicative of dying
703 or out-of-spec (ie, overclocked) hardware.
704 This option only does something on certain CPUs.
705 (AMD Athlon/Duron and Intel Pentium 4)
707 config X86_MCE_P4THERMAL
708 bool "check for P4 thermal throttling interrupt."
709 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
711 Enabling this feature will cause a message to be printed when the P4
712 enters thermal throttling.
715 bool "Enable VM86 support" if EMBEDDED
719 This option is required by programs like DOSEMU to run 16-bit legacy
720 code on X86 processors. It also may be needed by software like
721 XFree86 to initialize some video cards via BIOS. Disabling this
722 option saves about 6k.
725 tristate "Toshiba Laptop support"
728 This adds a driver to safely access the System Management Mode of
729 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
730 not work on models with a Phoenix BIOS. The System Management Mode
731 is used to set the BIOS and power saving options on Toshiba portables.
733 For information on utilities to make use of this driver see the
734 Toshiba Linux utilities web site at:
735 <http://www.buzzard.org.uk/toshiba/>.
737 Say Y if you intend to run this kernel on a Toshiba portable.
741 tristate "Dell laptop support"
743 This adds a driver to safely access the System Management Mode
744 of the CPU on the Dell Inspiron 8000. The System Management Mode
745 is used to read cpu temperature and cooling fan status and to
746 control the fans on the I8K portables.
748 This driver has been tested only on the Inspiron 8000 but it may
749 also work with other Dell laptops. You can force loading on other
750 models by passing the parameter `force=1' to the module. Use at
753 For information on utilities to make use of this driver see the
754 I8K Linux utilities web site at:
755 <http://people.debian.org/~dz/i8k/>
757 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
760 config X86_REBOOTFIXUPS
762 prompt "Enable X86 board specific fixups for reboot"
763 depends on X86_32 && X86
765 This enables chipset and/or board specific fixups to be done
766 in order to get reboot to work correctly. This is only needed on
767 some combinations of hardware and BIOS. The symptom, for which
768 this config is intended, is when reboot ends with a stalled/hung
771 Currently, the only fixup is for the Geode machines using
772 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
774 Say Y if you want to enable the fixup. Currently, it's safe to
775 enable this option even if you don't need it.
779 tristate "/dev/cpu/microcode - microcode support"
782 If you say Y here, you will be able to update the microcode on
783 certain Intel and AMD processors. The Intel support is for the
784 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
785 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
786 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
787 You will obviously need the actual microcode binary data itself
788 which is not shipped with the Linux kernel.
790 This option selects the general module only, you need to select
791 at least one vendor specific module as well.
793 To compile this driver as a module, choose M here: the
794 module will be called microcode.
796 config MICROCODE_INTEL
797 bool "Intel microcode patch loading support"
802 This options enables microcode patch loading support for Intel
805 For latest news and information on obtaining all the required
806 Intel ingredients for this driver, check:
807 <http://www.urbanmyth.org/microcode/>.
810 bool "AMD microcode patch loading support"
814 If you select this option, microcode patch loading support for AMD
815 processors will be enabled.
817 config MICROCODE_OLD_INTERFACE
822 tristate "/dev/cpu/*/msr - Model-specific register support"
824 This device gives privileged processes access to the x86
825 Model-Specific Registers (MSRs). It is a character device with
826 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
827 MSR accesses are directed to a specific CPU on multi-processor
831 tristate "/dev/cpu/*/cpuid - CPU information support"
833 This device gives processes access to the x86 CPUID instruction to
834 be executed on a specific processor. It is a character device
835 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
839 prompt "High Memory Support"
840 default HIGHMEM4G if !X86_NUMAQ
841 default HIGHMEM64G if X86_NUMAQ
846 depends on !X86_NUMAQ
848 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
849 However, the address space of 32-bit x86 processors is only 4
850 Gigabytes large. That means that, if you have a large amount of
851 physical memory, not all of it can be "permanently mapped" by the
852 kernel. The physical memory that's not permanently mapped is called
855 If you are compiling a kernel which will never run on a machine with
856 more than 1 Gigabyte total physical RAM, answer "off" here (default
857 choice and suitable for most users). This will result in a "3GB/1GB"
858 split: 3GB are mapped so that each process sees a 3GB virtual memory
859 space and the remaining part of the 4GB virtual memory space is used
860 by the kernel to permanently map as much physical memory as
863 If the machine has between 1 and 4 Gigabytes physical RAM, then
866 If more than 4 Gigabytes is used then answer "64GB" here. This
867 selection turns Intel PAE (Physical Address Extension) mode on.
868 PAE implements 3-level paging on IA32 processors. PAE is fully
869 supported by Linux, PAE mode is implemented on all recent Intel
870 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
871 then the kernel will not boot on CPUs that don't support PAE!
873 The actual amount of total physical memory will either be
874 auto detected or can be forced by using a kernel command line option
875 such as "mem=256M". (Try "man bootparam" or see the documentation of
876 your boot loader (lilo or loadlin) about how to pass options to the
877 kernel at boot time.)
879 If unsure, say "off".
883 depends on !X86_NUMAQ
885 Select this if you have a 32-bit processor and between 1 and 4
886 gigabytes of physical RAM.
890 depends on !M386 && !M486
893 Select this if you have a 32-bit processor and more than 4
894 gigabytes of physical RAM.
899 depends on EXPERIMENTAL
900 prompt "Memory split" if EMBEDDED
904 Select the desired split between kernel and user memory.
906 If the address range available to the kernel is less than the
907 physical memory installed, the remaining memory will be available
908 as "high memory". Accessing high memory is a little more costly
909 than low memory, as it needs to be mapped into the kernel first.
910 Note that increasing the kernel address space limits the range
911 available to user programs, making the address space there
912 tighter. Selecting anything other than the default 3G/1G split
913 will also likely make your kernel incompatible with binary-only
916 If you are not absolutely sure what you are doing, leave this
920 bool "3G/1G user/kernel split"
921 config VMSPLIT_3G_OPT
923 bool "3G/1G user/kernel split (for full 1G low memory)"
925 bool "2G/2G user/kernel split"
926 config VMSPLIT_2G_OPT
928 bool "2G/2G user/kernel split (for full 2G low memory)"
930 bool "1G/3G user/kernel split"
935 default 0xB0000000 if VMSPLIT_3G_OPT
936 default 0x80000000 if VMSPLIT_2G
937 default 0x78000000 if VMSPLIT_2G_OPT
938 default 0x40000000 if VMSPLIT_1G
944 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
948 prompt "PAE (Physical Address Extension) Support"
949 depends on X86_32 && !HIGHMEM4G
951 PAE is required for NX support, and furthermore enables
952 larger swapspace support for non-overcommit purposes. It
953 has the cost of more pagetable lookup overhead, and also
954 consumes more pagetable space per process.
956 config ARCH_PHYS_ADDR_T_64BIT
957 def_bool X86_64 || X86_PAE
959 # Common NUMA Features
961 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
963 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
965 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
967 Enable NUMA (Non Uniform Memory Access) support.
968 The kernel will try to allocate memory used by a CPU on the
969 local memory controller of the CPU and add some more
970 NUMA awareness to the kernel.
972 For 32-bit this is currently highly experimental and should be only
973 used for kernel development. It might also cause boot failures.
974 For 64-bit this is recommended on all multiprocessor Opteron systems.
975 If the system is EM64T, you should say N unless your system is
978 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
979 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
983 prompt "Old style AMD Opteron NUMA detection"
984 depends on X86_64 && NUMA && PCI
986 Enable K8 NUMA node topology detection. You should say Y here if
987 you have a multi processor AMD K8 system. This uses an old
988 method to read the NUMA configuration directly from the builtin
989 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
990 instead, which also takes priority if both are compiled in.
992 config X86_64_ACPI_NUMA
994 prompt "ACPI NUMA detection"
995 depends on X86_64 && NUMA && ACPI && PCI
998 Enable ACPI SRAT based node topology detection.
1000 # Some NUMA nodes have memory ranges that span
1001 # other nodes. Even though a pfn is valid and
1002 # between a node's start and end pfns, it may not
1003 # reside on that node. See memmap_init_zone()
1005 config NODES_SPAN_OTHER_NODES
1007 depends on X86_64_ACPI_NUMA
1010 bool "NUMA emulation"
1011 depends on X86_64 && NUMA
1013 Enable NUMA emulation. A flat machine will be split
1014 into virtual nodes when booted with "numa=fake=N", where N is the
1015 number of nodes. This is only useful for debugging.
1018 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1020 default "9" if MAXSMP
1021 default "6" if X86_64
1022 default "4" if X86_NUMAQ
1024 depends on NEED_MULTIPLE_NODES
1026 Specify the maximum number of NUMA Nodes available on the target
1027 system. Increases memory reserved to accomodate various tables.
1029 config HAVE_ARCH_BOOTMEM_NODE
1031 depends on X86_32 && NUMA
1033 config ARCH_HAVE_MEMORY_PRESENT
1035 depends on X86_32 && DISCONTIGMEM
1037 config NEED_NODE_MEMMAP_SIZE
1039 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1041 config HAVE_ARCH_ALLOC_REMAP
1043 depends on X86_32 && NUMA
1045 config ARCH_FLATMEM_ENABLE
1047 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1049 config ARCH_DISCONTIGMEM_ENABLE
1051 depends on NUMA && X86_32
1053 config ARCH_DISCONTIGMEM_DEFAULT
1055 depends on NUMA && X86_32
1057 config ARCH_SPARSEMEM_DEFAULT
1061 config ARCH_SPARSEMEM_ENABLE
1063 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC) || X86_GENERICARCH
1064 select SPARSEMEM_STATIC if X86_32
1065 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1067 config ARCH_SELECT_MEMORY_MODEL
1069 depends on ARCH_SPARSEMEM_ENABLE
1071 config ARCH_MEMORY_PROBE
1073 depends on MEMORY_HOTPLUG
1078 bool "Allocate 3rd-level pagetables from highmem"
1079 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1081 The VM uses one page table entry for each page of physical memory.
1082 For systems with a lot of RAM, this can be wasteful of precious
1083 low memory. Setting this option will put user-space page table
1084 entries in high memory.
1086 config X86_CHECK_BIOS_CORRUPTION
1087 bool "Check for low memory corruption"
1089 Periodically check for memory corruption in low memory, which
1090 is suspected to be caused by BIOS. Even when enabled in the
1091 configuration, it is disabled at runtime. Enable it by
1092 setting "memory_corruption_check=1" on the kernel command
1093 line. By default it scans the low 64k of memory every 60
1094 seconds; see the memory_corruption_check_size and
1095 memory_corruption_check_period parameters in
1096 Documentation/kernel-parameters.txt to adjust this.
1098 When enabled with the default parameters, this option has
1099 almost no overhead, as it reserves a relatively small amount
1100 of memory and scans it infrequently. It both detects corruption
1101 and prevents it from affecting the running system.
1103 It is, however, intended as a diagnostic tool; if repeatable
1104 BIOS-originated corruption always affects the same memory,
1105 you can use memmap= to prevent the kernel from using that
1108 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1109 bool "Set the default setting of memory_corruption_check"
1110 depends on X86_CHECK_BIOS_CORRUPTION
1113 Set whether the default state of memory_corruption_check is
1116 config X86_RESERVE_LOW_64K
1117 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1120 Reserve the first 64K of physical RAM on BIOSes that are known
1121 to potentially corrupt that memory range. A numbers of BIOSes are
1122 known to utilize this area during suspend/resume, so it must not
1123 be used by the kernel.
1125 Set this to N if you are absolutely sure that you trust the BIOS
1126 to get all its memory reservations and usages right.
1128 If you have doubts about the BIOS (e.g. suspend/resume does not
1129 work or there's kernel crashes after certain hardware hotplug
1130 events) and it's not AMI or Phoenix, then you might want to enable
1131 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1132 corruption patterns.
1136 config MATH_EMULATION
1138 prompt "Math emulation" if X86_32
1140 Linux can emulate a math coprocessor (used for floating point
1141 operations) if you don't have one. 486DX and Pentium processors have
1142 a math coprocessor built in, 486SX and 386 do not, unless you added
1143 a 487DX or 387, respectively. (The messages during boot time can
1144 give you some hints here ["man dmesg"].) Everyone needs either a
1145 coprocessor or this emulation.
1147 If you don't have a math coprocessor, you need to say Y here; if you
1148 say Y here even though you have a coprocessor, the coprocessor will
1149 be used nevertheless. (This behavior can be changed with the kernel
1150 command line option "no387", which comes handy if your coprocessor
1151 is broken. Try "man bootparam" or see the documentation of your boot
1152 loader (lilo or loadlin) about how to pass options to the kernel at
1153 boot time.) This means that it is a good idea to say Y here if you
1154 intend to use this kernel on different machines.
1156 More information about the internals of the Linux math coprocessor
1157 emulation can be found in <file:arch/x86/math-emu/README>.
1159 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1160 kernel, it won't hurt.
1163 bool "MTRR (Memory Type Range Register) support"
1165 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1166 the Memory Type Range Registers (MTRRs) may be used to control
1167 processor access to memory ranges. This is most useful if you have
1168 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1169 allows bus write transfers to be combined into a larger transfer
1170 before bursting over the PCI/AGP bus. This can increase performance
1171 of image write operations 2.5 times or more. Saying Y here creates a
1172 /proc/mtrr file which may be used to manipulate your processor's
1173 MTRRs. Typically the X server should use this.
1175 This code has a reasonably generic interface so that similar
1176 control registers on other processors can be easily supported
1179 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1180 Registers (ARRs) which provide a similar functionality to MTRRs. For
1181 these, the ARRs are used to emulate the MTRRs.
1182 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1183 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1184 write-combining. All of these processors are supported by this code
1185 and it makes sense to say Y here if you have one of them.
1187 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1188 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1189 can lead to all sorts of problems, so it's good to say Y here.
1191 You can safely say Y even if your machine doesn't have MTRRs, you'll
1192 just add about 9 KB to your kernel.
1194 See <file:Documentation/x86/mtrr.txt> for more information.
1196 config MTRR_SANITIZER
1198 prompt "MTRR cleanup support"
1201 Convert MTRR layout from continuous to discrete, so X drivers can
1202 add writeback entries.
1204 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1205 The largest mtrr entry size for a continous block can be set with
1210 config MTRR_SANITIZER_ENABLE_DEFAULT
1211 int "MTRR cleanup enable value (0-1)"
1214 depends on MTRR_SANITIZER
1216 Enable mtrr cleanup default value
1218 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1219 int "MTRR cleanup spare reg num (0-7)"
1222 depends on MTRR_SANITIZER
1224 mtrr cleanup spare entries default, it can be changed via
1225 mtrr_spare_reg_nr=N on the kernel command line.
1229 prompt "x86 PAT support"
1232 Use PAT attributes to setup page level cache control.
1234 PATs are the modern equivalents of MTRRs and are much more
1235 flexible than MTRRs.
1237 Say N here if you see bootup problems (boot crash, boot hang,
1238 spontaneous reboots) or a non-working video driver.
1244 prompt "EFI runtime service support"
1247 This enables the kernel to use EFI runtime services that are
1248 available (such as the EFI variable services).
1250 This option is only useful on systems that have EFI firmware.
1251 In addition, you should use the latest ELILO loader available
1252 at <http://elilo.sourceforge.net> in order to take advantage
1253 of EFI runtime services. However, even with this option, the
1254 resultant kernel should continue to boot on existing non-EFI
1259 prompt "Enable kernel irq balancing"
1260 depends on X86_32 && SMP && X86_IO_APIC
1262 The default yes will allow the kernel to do irq load balancing.
1263 Saying no will keep the kernel from doing irq load balancing.
1267 prompt "Enable seccomp to safely compute untrusted bytecode"
1269 This kernel feature is useful for number crunching applications
1270 that may need to compute untrusted bytecode during their
1271 execution. By using pipes or other transports made available to
1272 the process as file descriptors supporting the read/write
1273 syscalls, it's possible to isolate those applications in
1274 their own address space using seccomp. Once seccomp is
1275 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1276 and the task is only allowed to execute a few safe syscalls
1277 defined by each seccomp mode.
1279 If unsure, say Y. Only embedded should say N here.
1281 config CC_STACKPROTECTOR
1282 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1283 depends on X86_64 && EXPERIMENTAL && BROKEN
1285 This option turns on the -fstack-protector GCC feature. This
1286 feature puts, at the beginning of critical functions, a canary
1287 value on the stack just before the return address, and validates
1288 the value just before actually returning. Stack based buffer
1289 overflows (that need to overwrite this return address) now also
1290 overwrite the canary, which gets detected and the attack is then
1291 neutralized via a kernel panic.
1293 This feature requires gcc version 4.2 or above, or a distribution
1294 gcc with the feature backported. Older versions are automatically
1295 detected and for those versions, this configuration option is ignored.
1297 config CC_STACKPROTECTOR_ALL
1298 bool "Use stack-protector for all functions"
1299 depends on CC_STACKPROTECTOR
1301 Normally, GCC only inserts the canary value protection for
1302 functions that use large-ish on-stack buffers. By enabling
1303 this option, GCC will be asked to do this for ALL functions.
1305 source kernel/Kconfig.hz
1308 bool "kexec system call"
1309 depends on X86_BIOS_REBOOT
1311 kexec is a system call that implements the ability to shutdown your
1312 current kernel, and to start another kernel. It is like a reboot
1313 but it is independent of the system firmware. And like a reboot
1314 you can start any kernel with it, not just Linux.
1316 The name comes from the similarity to the exec system call.
1318 It is an ongoing process to be certain the hardware in a machine
1319 is properly shutdown, so do not be surprised if this code does not
1320 initially work for you. It may help to enable device hotplugging
1321 support. As of this writing the exact hardware interface is
1322 strongly in flux, so no good recommendation can be made.
1325 bool "kernel crash dumps"
1326 depends on X86_64 || (X86_32 && HIGHMEM)
1328 Generate crash dump after being started by kexec.
1329 This should be normally only set in special crash dump kernels
1330 which are loaded in the main kernel with kexec-tools into
1331 a specially reserved region and then later executed after
1332 a crash by kdump/kexec. The crash dump kernel must be compiled
1333 to a memory address not used by the main kernel or BIOS using
1334 PHYSICAL_START, or it must be built as a relocatable image
1335 (CONFIG_RELOCATABLE=y).
1336 For more details see Documentation/kdump/kdump.txt
1339 bool "kexec jump (EXPERIMENTAL)"
1340 depends on EXPERIMENTAL
1341 depends on KEXEC && HIBERNATION && X86_32
1343 Jump between original kernel and kexeced kernel and invoke
1344 code in physical address mode via KEXEC
1346 config PHYSICAL_START
1347 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1348 default "0x1000000" if X86_NUMAQ
1349 default "0x200000" if X86_64
1352 This gives the physical address where the kernel is loaded.
1354 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1355 bzImage will decompress itself to above physical address and
1356 run from there. Otherwise, bzImage will run from the address where
1357 it has been loaded by the boot loader and will ignore above physical
1360 In normal kdump cases one does not have to set/change this option
1361 as now bzImage can be compiled as a completely relocatable image
1362 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1363 address. This option is mainly useful for the folks who don't want
1364 to use a bzImage for capturing the crash dump and want to use a
1365 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1366 to be specifically compiled to run from a specific memory area
1367 (normally a reserved region) and this option comes handy.
1369 So if you are using bzImage for capturing the crash dump, leave
1370 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1371 Otherwise if you plan to use vmlinux for capturing the crash dump
1372 change this value to start of the reserved region (Typically 16MB
1373 0x1000000). In other words, it can be set based on the "X" value as
1374 specified in the "crashkernel=YM@XM" command line boot parameter
1375 passed to the panic-ed kernel. Typically this parameter is set as
1376 crashkernel=64M@16M. Please take a look at
1377 Documentation/kdump/kdump.txt for more details about crash dumps.
1379 Usage of bzImage for capturing the crash dump is recommended as
1380 one does not have to build two kernels. Same kernel can be used
1381 as production kernel and capture kernel. Above option should have
1382 gone away after relocatable bzImage support is introduced. But it
1383 is present because there are users out there who continue to use
1384 vmlinux for dump capture. This option should go away down the
1387 Don't change this unless you know what you are doing.
1390 bool "Build a relocatable kernel (EXPERIMENTAL)"
1391 depends on EXPERIMENTAL
1393 This builds a kernel image that retains relocation information
1394 so it can be loaded someplace besides the default 1MB.
1395 The relocations tend to make the kernel binary about 10% larger,
1396 but are discarded at runtime.
1398 One use is for the kexec on panic case where the recovery kernel
1399 must live at a different physical address than the primary
1402 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1403 it has been loaded at and the compile time physical address
1404 (CONFIG_PHYSICAL_START) is ignored.
1406 config PHYSICAL_ALIGN
1408 prompt "Alignment value to which kernel should be aligned" if X86_32
1409 default "0x100000" if X86_32
1410 default "0x200000" if X86_64
1411 range 0x2000 0x400000
1413 This value puts the alignment restrictions on physical address
1414 where kernel is loaded and run from. Kernel is compiled for an
1415 address which meets above alignment restriction.
1417 If bootloader loads the kernel at a non-aligned address and
1418 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1419 address aligned to above value and run from there.
1421 If bootloader loads the kernel at a non-aligned address and
1422 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1423 load address and decompress itself to the address it has been
1424 compiled for and run from there. The address for which kernel is
1425 compiled already meets above alignment restrictions. Hence the
1426 end result is that kernel runs from a physical address meeting
1427 above alignment restrictions.
1429 Don't change this unless you know what you are doing.
1432 bool "Support for hot-pluggable CPUs"
1433 depends on SMP && HOTPLUG && !X86_VOYAGER
1435 Say Y here to allow turning CPUs off and on. CPUs can be
1436 controlled through /sys/devices/system/cpu.
1437 ( Note: power management support will enable this option
1438 automatically on SMP systems. )
1439 Say N if you want to disable CPU hotplug.
1443 prompt "Compat VDSO support"
1444 depends on X86_32 || IA32_EMULATION
1446 Map the 32-bit VDSO to the predictable old-style address too.
1448 Say N here if you are running a sufficiently recent glibc
1449 version (2.3.3 or later), to remove the high-mapped
1450 VDSO mapping and to exclusively use the randomized VDSO.
1455 bool "Built-in kernel command line"
1458 Allow for specifying boot arguments to the kernel at
1459 build time. On some systems (e.g. embedded ones), it is
1460 necessary or convenient to provide some or all of the
1461 kernel boot arguments with the kernel itself (that is,
1462 to not rely on the boot loader to provide them.)
1464 To compile command line arguments into the kernel,
1465 set this option to 'Y', then fill in the
1466 the boot arguments in CONFIG_CMDLINE.
1468 Systems with fully functional boot loaders (i.e. non-embedded)
1469 should leave this option set to 'N'.
1472 string "Built-in kernel command string"
1473 depends on CMDLINE_BOOL
1476 Enter arguments here that should be compiled into the kernel
1477 image and used at boot time. If the boot loader provides a
1478 command line at boot time, it is appended to this string to
1479 form the full kernel command line, when the system boots.
1481 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1482 change this behavior.
1484 In most cases, the command line (whether built-in or provided
1485 by the boot loader) should specify the device for the root
1488 config CMDLINE_OVERRIDE
1489 bool "Built-in command line overrides boot loader arguments"
1491 depends on CMDLINE_BOOL
1493 Set this option to 'Y' to have the kernel ignore the boot loader
1494 command line, and use ONLY the built-in command line.
1496 This is used to work around broken boot loaders. This should
1497 be set to 'N' under normal conditions.
1501 config ARCH_ENABLE_MEMORY_HOTPLUG
1503 depends on X86_64 || (X86_32 && HIGHMEM)
1505 config HAVE_ARCH_EARLY_PFN_TO_NID
1509 menu "Power management options"
1510 depends on !X86_VOYAGER
1512 config ARCH_HIBERNATION_HEADER
1514 depends on X86_64 && HIBERNATION
1516 source "kernel/power/Kconfig"
1518 source "drivers/acpi/Kconfig"
1523 depends on APM || APM_MODULE
1526 tristate "APM (Advanced Power Management) BIOS support"
1527 depends on X86_32 && PM_SLEEP
1529 APM is a BIOS specification for saving power using several different
1530 techniques. This is mostly useful for battery powered laptops with
1531 APM compliant BIOSes. If you say Y here, the system time will be
1532 reset after a RESUME operation, the /proc/apm device will provide
1533 battery status information, and user-space programs will receive
1534 notification of APM "events" (e.g. battery status change).
1536 If you select "Y" here, you can disable actual use of the APM
1537 BIOS by passing the "apm=off" option to the kernel at boot time.
1539 Note that the APM support is almost completely disabled for
1540 machines with more than one CPU.
1542 In order to use APM, you will need supporting software. For location
1543 and more information, read <file:Documentation/power/pm.txt> and the
1544 Battery Powered Linux mini-HOWTO, available from
1545 <http://www.tldp.org/docs.html#howto>.
1547 This driver does not spin down disk drives (see the hdparm(8)
1548 manpage ("man 8 hdparm") for that), and it doesn't turn off
1549 VESA-compliant "green" monitors.
1551 This driver does not support the TI 4000M TravelMate and the ACER
1552 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1553 desktop machines also don't have compliant BIOSes, and this driver
1554 may cause those machines to panic during the boot phase.
1556 Generally, if you don't have a battery in your machine, there isn't
1557 much point in using this driver and you should say N. If you get
1558 random kernel OOPSes or reboots that don't seem to be related to
1559 anything, try disabling/enabling this option (or disabling/enabling
1562 Some other things you should try when experiencing seemingly random,
1565 1) make sure that you have enough swap space and that it is
1567 2) pass the "no-hlt" option to the kernel
1568 3) switch on floating point emulation in the kernel and pass
1569 the "no387" option to the kernel
1570 4) pass the "floppy=nodma" option to the kernel
1571 5) pass the "mem=4M" option to the kernel (thereby disabling
1572 all but the first 4 MB of RAM)
1573 6) make sure that the CPU is not over clocked.
1574 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1575 8) disable the cache from your BIOS settings
1576 9) install a fan for the video card or exchange video RAM
1577 10) install a better fan for the CPU
1578 11) exchange RAM chips
1579 12) exchange the motherboard.
1581 To compile this driver as a module, choose M here: the
1582 module will be called apm.
1586 config APM_IGNORE_USER_SUSPEND
1587 bool "Ignore USER SUSPEND"
1589 This option will ignore USER SUSPEND requests. On machines with a
1590 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1591 series notebooks, it is necessary to say Y because of a BIOS bug.
1593 config APM_DO_ENABLE
1594 bool "Enable PM at boot time"
1596 Enable APM features at boot time. From page 36 of the APM BIOS
1597 specification: "When disabled, the APM BIOS does not automatically
1598 power manage devices, enter the Standby State, enter the Suspend
1599 State, or take power saving steps in response to CPU Idle calls."
1600 This driver will make CPU Idle calls when Linux is idle (unless this
1601 feature is turned off -- see "Do CPU IDLE calls", below). This
1602 should always save battery power, but more complicated APM features
1603 will be dependent on your BIOS implementation. You may need to turn
1604 this option off if your computer hangs at boot time when using APM
1605 support, or if it beeps continuously instead of suspending. Turn
1606 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1607 T400CDT. This is off by default since most machines do fine without
1611 bool "Make CPU Idle calls when idle"
1613 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1614 On some machines, this can activate improved power savings, such as
1615 a slowed CPU clock rate, when the machine is idle. These idle calls
1616 are made after the idle loop has run for some length of time (e.g.,
1617 333 mS). On some machines, this will cause a hang at boot time or
1618 whenever the CPU becomes idle. (On machines with more than one CPU,
1619 this option does nothing.)
1621 config APM_DISPLAY_BLANK
1622 bool "Enable console blanking using APM"
1624 Enable console blanking using the APM. Some laptops can use this to
1625 turn off the LCD backlight when the screen blanker of the Linux
1626 virtual console blanks the screen. Note that this is only used by
1627 the virtual console screen blanker, and won't turn off the backlight
1628 when using the X Window system. This also doesn't have anything to
1629 do with your VESA-compliant power-saving monitor. Further, this
1630 option doesn't work for all laptops -- it might not turn off your
1631 backlight at all, or it might print a lot of errors to the console,
1632 especially if you are using gpm.
1634 config APM_ALLOW_INTS
1635 bool "Allow interrupts during APM BIOS calls"
1637 Normally we disable external interrupts while we are making calls to
1638 the APM BIOS as a measure to lessen the effects of a badly behaving
1639 BIOS implementation. The BIOS should reenable interrupts if it
1640 needs to. Unfortunately, some BIOSes do not -- especially those in
1641 many of the newer IBM Thinkpads. If you experience hangs when you
1642 suspend, try setting this to Y. Otherwise, say N.
1644 config APM_REAL_MODE_POWER_OFF
1645 bool "Use real mode APM BIOS call to power off"
1647 Use real mode APM BIOS calls to switch off the computer. This is
1648 a work-around for a number of buggy BIOSes. Switch this option on if
1649 your computer crashes instead of powering off properly.
1653 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1655 source "drivers/cpuidle/Kconfig"
1660 menu "Bus options (PCI etc.)"
1665 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1667 Find out whether you have a PCI motherboard. PCI is the name of a
1668 bus system, i.e. the way the CPU talks to the other stuff inside
1669 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1670 VESA. If you have PCI, say Y, otherwise N.
1673 prompt "PCI access mode"
1674 depends on X86_32 && PCI
1677 On PCI systems, the BIOS can be used to detect the PCI devices and
1678 determine their configuration. However, some old PCI motherboards
1679 have BIOS bugs and may crash if this is done. Also, some embedded
1680 PCI-based systems don't have any BIOS at all. Linux can also try to
1681 detect the PCI hardware directly without using the BIOS.
1683 With this option, you can specify how Linux should detect the
1684 PCI devices. If you choose "BIOS", the BIOS will be used,
1685 if you choose "Direct", the BIOS won't be used, and if you
1686 choose "MMConfig", then PCI Express MMCONFIG will be used.
1687 If you choose "Any", the kernel will try MMCONFIG, then the
1688 direct access method and falls back to the BIOS if that doesn't
1689 work. If unsure, go with the default, which is "Any".
1694 config PCI_GOMMCONFIG
1711 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1713 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1716 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1720 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1724 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1731 bool "Support mmconfig PCI config space access"
1732 depends on X86_64 && PCI && ACPI
1735 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1736 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1738 DMA remapping (DMAR) devices support enables independent address
1739 translations for Direct Memory Access (DMA) from devices.
1740 These DMA remapping devices are reported via ACPI tables
1741 and include PCI device scope covered by these DMA
1746 prompt "Support for Graphics workaround"
1749 Current Graphics drivers tend to use physical address
1750 for DMA and avoid using DMA APIs. Setting this config
1751 option permits the IOMMU driver to set a unity map for
1752 all the OS-visible memory. Hence the driver can continue
1753 to use physical addresses for DMA.
1755 config DMAR_FLOPPY_WA
1759 Floppy disk drivers are know to bypass DMA API calls
1760 thereby failing to work when IOMMU is enabled. This
1761 workaround will setup a 1:1 mapping for the first
1762 16M to make floppy (an ISA device) work.
1765 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1766 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1768 Supports Interrupt remapping for IO-APIC and MSI devices.
1769 To use x2apic mode in the CPU's which support x2APIC enhancements or
1770 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1772 source "drivers/pci/pcie/Kconfig"
1774 source "drivers/pci/Kconfig"
1776 # x86_64 have no ISA slots, but do have ISA-style DMA.
1784 depends on !X86_VOYAGER
1786 Find out whether you have ISA slots on your motherboard. ISA is the
1787 name of a bus system, i.e. the way the CPU talks to the other stuff
1788 inside your box. Other bus systems are PCI, EISA, MicroChannel
1789 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1790 newer boards don't support it. If you have ISA, say Y, otherwise N.
1796 The Extended Industry Standard Architecture (EISA) bus was
1797 developed as an open alternative to the IBM MicroChannel bus.
1799 The EISA bus provided some of the features of the IBM MicroChannel
1800 bus while maintaining backward compatibility with cards made for
1801 the older ISA bus. The EISA bus saw limited use between 1988 and
1802 1995 when it was made obsolete by the PCI bus.
1804 Say Y here if you are building a kernel for an EISA-based machine.
1808 source "drivers/eisa/Kconfig"
1811 bool "MCA support" if !X86_VOYAGER
1812 default y if X86_VOYAGER
1814 MicroChannel Architecture is found in some IBM PS/2 machines and
1815 laptops. It is a bus system similar to PCI or ISA. See
1816 <file:Documentation/mca.txt> (and especially the web page given
1817 there) before attempting to build an MCA bus kernel.
1819 source "drivers/mca/Kconfig"
1822 tristate "NatSemi SCx200 support"
1823 depends on !X86_VOYAGER
1825 This provides basic support for National Semiconductor's
1826 (now AMD's) Geode processors. The driver probes for the
1827 PCI-IDs of several on-chip devices, so its a good dependency
1828 for other scx200_* drivers.
1830 If compiled as a module, the driver is named scx200.
1832 config SCx200HR_TIMER
1833 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1834 depends on SCx200 && GENERIC_TIME
1837 This driver provides a clocksource built upon the on-chip
1838 27MHz high-resolution timer. Its also a workaround for
1839 NSC Geode SC-1100's buggy TSC, which loses time when the
1840 processor goes idle (as is done by the scheduler). The
1841 other workaround is idle=poll boot option.
1843 config GEODE_MFGPT_TIMER
1845 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1846 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1848 This driver provides a clock event source based on the MFGPT
1849 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1850 MFGPTs have a better resolution and max interval than the
1851 generic PIT, and are suitable for use as high-res timers.
1854 bool "One Laptop Per Child support"
1857 Add support for detecting the unique features of the OLPC
1864 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1866 source "drivers/pcmcia/Kconfig"
1868 source "drivers/pci/hotplug/Kconfig"
1873 menu "Executable file formats / Emulations"
1875 source "fs/Kconfig.binfmt"
1877 config IA32_EMULATION
1878 bool "IA32 Emulation"
1880 select COMPAT_BINFMT_ELF
1882 Include code to run 32-bit programs under a 64-bit kernel. You should
1883 likely turn this on, unless you're 100% sure that you don't have any
1884 32-bit programs left.
1887 tristate "IA32 a.out support"
1888 depends on IA32_EMULATION
1890 Support old a.out binaries in the 32bit emulation.
1894 depends on IA32_EMULATION
1896 config COMPAT_FOR_U64_ALIGNMENT
1900 config SYSVIPC_COMPAT
1902 depends on COMPAT && SYSVIPC
1907 source "net/Kconfig"
1909 source "drivers/Kconfig"
1911 source "drivers/firmware/Kconfig"
1915 source "arch/x86/Kconfig.debug"
1917 source "security/Kconfig"
1919 source "crypto/Kconfig"
1921 source "arch/x86/kvm/Kconfig"
1923 source "lib/Kconfig"
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