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_PERF_EVENTS if (!M386 && !M486)
28 select HAVE_IOREMAP_PROT
30 select ARCH_WANT_OPTIONAL_GPIOLIB
31 select ARCH_WANT_FRAME_POINTERS
33 select HAVE_KRETPROBES
35 select HAVE_FTRACE_MCOUNT_RECORD
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
58 select HAVE_ARCH_KMEMCHECK
59 select HAVE_USER_RETURN_NOTIFIER
61 config INSTRUCTION_DECODER
62 def_bool (KPROBES || PERF_EVENTS)
66 default "elf32-i386" if X86_32
67 default "elf64-x86-64" if X86_64
71 default "arch/x86/configs/i386_defconfig" if X86_32
72 default "arch/x86/configs/x86_64_defconfig" if X86_64
77 config GENERIC_CMOS_UPDATE
80 config CLOCKSOURCE_WATCHDOG
83 config GENERIC_CLOCKEVENTS
86 config GENERIC_CLOCKEVENTS_BROADCAST
88 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
90 config LOCKDEP_SUPPORT
93 config STACKTRACE_SUPPORT
96 config HAVE_LATENCYTOP_SUPPORT
108 config NEED_DMA_MAP_STATE
109 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
111 config GENERIC_ISA_DMA
120 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
122 config GENERIC_BUG_RELATIVE_POINTERS
125 config GENERIC_HWEIGHT
131 config ARCH_MAY_HAVE_PC_FDC
134 config RWSEM_GENERIC_SPINLOCK
137 config RWSEM_XCHGADD_ALGORITHM
140 config ARCH_HAS_CPU_IDLE_WAIT
143 config GENERIC_CALIBRATE_DELAY
146 config GENERIC_TIME_VSYSCALL
150 config ARCH_HAS_CPU_RELAX
153 config ARCH_HAS_DEFAULT_IDLE
156 config ARCH_HAS_CACHE_LINE_SIZE
159 config HAVE_SETUP_PER_CPU_AREA
162 config NEED_PER_CPU_EMBED_FIRST_CHUNK
165 config NEED_PER_CPU_PAGE_FIRST_CHUNK
168 config HAVE_CPUMASK_OF_CPU_MAP
171 config ARCH_HIBERNATION_POSSIBLE
174 config ARCH_SUSPEND_POSSIBLE
181 config ARCH_POPULATES_NODE_MAP
188 config ARCH_SUPPORTS_OPTIMIZED_INLINING
191 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
194 config HAVE_EARLY_RES
197 config HAVE_INTEL_TXT
199 depends on EXPERIMENTAL && DMAR && ACPI
201 # Use the generic interrupt handling code in kernel/irq/:
202 config GENERIC_HARDIRQS
206 config GENERIC_HARDIRQS_NO__DO_IRQ
209 config GENERIC_IRQ_PROBE
213 config GENERIC_PENDING_IRQ
215 depends on GENERIC_HARDIRQS && SMP
218 config USE_GENERIC_SMP_HELPERS
224 depends on X86_32 && SMP
228 depends on X86_64 && SMP
235 config X86_TRAMPOLINE
237 depends on SMP || (64BIT && ACPI_SLEEP)
240 config X86_32_LAZY_GS
242 depends on X86_32 && !CC_STACKPROTECTOR
246 source "init/Kconfig"
247 source "kernel/Kconfig.freezer"
249 menu "Processor type and features"
251 source "kernel/time/Kconfig"
254 bool "Symmetric multi-processing support"
256 This enables support for systems with more than one CPU. If you have
257 a system with only one CPU, like most personal computers, say N. If
258 you have a system with more than one CPU, say Y.
260 If you say N here, the kernel will run on single and multiprocessor
261 machines, but will use only one CPU of a multiprocessor machine. If
262 you say Y here, the kernel will run on many, but not all,
263 singleprocessor machines. On a singleprocessor machine, the kernel
264 will run faster if you say N here.
266 Note that if you say Y here and choose architecture "586" or
267 "Pentium" under "Processor family", the kernel will not work on 486
268 architectures. Similarly, multiprocessor kernels for the "PPro"
269 architecture may not work on all Pentium based boards.
271 People using multiprocessor machines who say Y here should also say
272 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
273 Management" code will be disabled if you say Y here.
275 See also <file:Documentation/i386/IO-APIC.txt>,
276 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
277 <http://www.tldp.org/docs.html#howto>.
279 If you don't know what to do here, say N.
282 bool "Support x2apic"
283 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
285 This enables x2apic support on CPUs that have this feature.
287 This allows 32-bit apic IDs (so it can support very large systems),
288 and accesses the local apic via MSRs not via mmio.
290 If you don't know what to do here, say N.
293 bool "Support sparse irq numbering"
294 depends on PCI_MSI || HT_IRQ
296 This enables support for sparse irqs. This is useful for distro
297 kernels that want to define a high CONFIG_NR_CPUS value but still
298 want to have low kernel memory footprint on smaller machines.
300 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
301 out the irq_desc[] array in a more NUMA-friendly way. )
303 If you don't know what to do here, say N.
307 depends on SPARSE_IRQ && NUMA
310 bool "Enable MPS table" if ACPI
312 depends on X86_LOCAL_APIC
314 For old smp systems that do not have proper acpi support. Newer systems
315 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
318 bool "Support for big SMP systems with more than 8 CPUs"
319 depends on X86_32 && SMP
321 This option is needed for the systems that have more than 8 CPUs
324 config X86_EXTENDED_PLATFORM
325 bool "Support for extended (non-PC) x86 platforms"
328 If you disable this option then the kernel will only support
329 standard PC platforms. (which covers the vast majority of
332 If you enable this option then you'll be able to select support
333 for the following (non-PC) 32 bit x86 platforms:
337 SGI 320/540 (Visual Workstation)
338 Summit/EXA (IBM x440)
339 Unisys ES7000 IA32 series
340 Moorestown MID devices
342 If you have one of these systems, or if you want to build a
343 generic distribution kernel, say Y here - otherwise say N.
347 config X86_EXTENDED_PLATFORM
348 bool "Support for extended (non-PC) x86 platforms"
351 If you disable this option then the kernel will only support
352 standard PC platforms. (which covers the vast majority of
355 If you enable this option then you'll be able to select support
356 for the following (non-PC) 64 bit x86 platforms:
360 If you have one of these systems, or if you want to build a
361 generic distribution kernel, say Y here - otherwise say N.
363 # This is an alphabetically sorted list of 64 bit extended platforms
364 # Please maintain the alphabetic order if and when there are additions
369 depends on X86_64 && PCI
370 depends on X86_EXTENDED_PLATFORM
372 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
373 supposed to run on these EM64T-based machines. Only choose this option
374 if you have one of these machines.
377 bool "SGI Ultraviolet"
379 depends on X86_EXTENDED_PLATFORM
381 depends on X86_X2APIC
383 This option is needed in order to support SGI Ultraviolet systems.
384 If you don't have one of these, you should say N here.
386 # Following is an alphabetically sorted list of 32 bit extended platforms
387 # Please maintain the alphabetic order if and when there are additions
392 depends on X86_EXTENDED_PLATFORM
394 Select this for an AMD Elan processor.
396 Do not use this option for K6/Athlon/Opteron processors!
398 If unsure, choose "PC-compatible" instead.
401 bool "Moorestown MID platform"
405 depends on X86_EXTENDED_PLATFORM
406 depends on X86_IO_APIC
409 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
410 Internet Device(MID) platform. Moorestown consists of two chips:
411 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
412 Unlike standard x86 PCs, Moorestown does not have many legacy devices
413 nor standard legacy replacement devices/features. e.g. Moorestown does
414 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
417 bool "RDC R-321x SoC"
419 depends on X86_EXTENDED_PLATFORM
421 select X86_REBOOTFIXUPS
423 This option is needed for RDC R-321x system-on-chip, also known
425 If you don't have one of these chips, you should say N here.
427 config X86_32_NON_STANDARD
428 bool "Support non-standard 32-bit SMP architectures"
429 depends on X86_32 && SMP
430 depends on X86_EXTENDED_PLATFORM
432 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
433 subarchitectures. It is intended for a generic binary kernel.
434 if you select them all, kernel will probe it one by one. and will
437 # Alphabetically sorted list of Non standard 32 bit platforms
440 bool "NUMAQ (IBM/Sequent)"
441 depends on X86_32_NON_STANDARD
446 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
447 NUMA multiquad box. This changes the way that processors are
448 bootstrapped, and uses Clustered Logical APIC addressing mode instead
449 of Flat Logical. You will need a new lynxer.elf file to flash your
450 firmware with - send email to <Martin.Bligh@us.ibm.com>.
452 config X86_SUPPORTS_MEMORY_FAILURE
454 # MCE code calls memory_failure():
456 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
457 depends on !X86_NUMAQ
458 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
459 depends on X86_64 || !SPARSEMEM
460 select ARCH_SUPPORTS_MEMORY_FAILURE
464 bool "SGI 320/540 (Visual Workstation)"
465 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
466 depends on X86_32_NON_STANDARD
468 The SGI Visual Workstation series is an IA32-based workstation
469 based on SGI systems chips with some legacy PC hardware attached.
471 Say Y here to create a kernel to run on the SGI 320 or 540.
473 A kernel compiled for the Visual Workstation will run on general
474 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
477 bool "Summit/EXA (IBM x440)"
478 depends on X86_32_NON_STANDARD
480 This option is needed for IBM systems that use the Summit/EXA chipset.
481 In particular, it is needed for the x440.
484 bool "Unisys ES7000 IA32 series"
485 depends on X86_32_NON_STANDARD && X86_BIGSMP
487 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
488 supposed to run on an IA32-based Unisys ES7000 system.
490 config SCHED_OMIT_FRAME_POINTER
492 prompt "Single-depth WCHAN output"
495 Calculate simpler /proc/<PID>/wchan values. If this option
496 is disabled then wchan values will recurse back to the
497 caller function. This provides more accurate wchan values,
498 at the expense of slightly more scheduling overhead.
500 If in doubt, say "Y".
502 menuconfig PARAVIRT_GUEST
503 bool "Paravirtualized guest support"
505 Say Y here to get to see options related to running Linux under
506 various hypervisors. This option alone does not add any kernel code.
508 If you say N, all options in this submenu will be skipped and disabled.
512 source "arch/x86/xen/Kconfig"
515 bool "VMI Guest support (DEPRECATED)"
519 VMI provides a paravirtualized interface to the VMware ESX server
520 (it could be used by other hypervisors in theory too, but is not
521 at the moment), by linking the kernel to a GPL-ed ROM module
522 provided by the hypervisor.
524 As of September 2009, VMware has started a phased retirement
525 of this feature from VMware's products. Please see
526 feature-removal-schedule.txt for details. If you are
527 planning to enable this option, please note that you cannot
528 live migrate a VMI enabled VM to a future VMware product,
529 which doesn't support VMI. So if you expect your kernel to
530 seamlessly migrate to newer VMware products, keep this
534 bool "KVM paravirtualized clock"
536 select PARAVIRT_CLOCK
538 Turning on this option will allow you to run a paravirtualized clock
539 when running over the KVM hypervisor. Instead of relying on a PIT
540 (or probably other) emulation by the underlying device model, the host
541 provides the guest with timing infrastructure such as time of day, and
545 bool "KVM Guest support"
548 This option enables various optimizations for running under the KVM
551 source "arch/x86/lguest/Kconfig"
554 bool "Enable paravirtualization code"
556 This changes the kernel so it can modify itself when it is run
557 under a hypervisor, potentially improving performance significantly
558 over full virtualization. However, when run without a hypervisor
559 the kernel is theoretically slower and slightly larger.
561 config PARAVIRT_SPINLOCKS
562 bool "Paravirtualization layer for spinlocks"
563 depends on PARAVIRT && SMP && EXPERIMENTAL
565 Paravirtualized spinlocks allow a pvops backend to replace the
566 spinlock implementation with something virtualization-friendly
567 (for example, block the virtual CPU rather than spinning).
569 Unfortunately the downside is an up to 5% performance hit on
570 native kernels, with various workloads.
572 If you are unsure how to answer this question, answer N.
574 config PARAVIRT_CLOCK
580 config PARAVIRT_DEBUG
581 bool "paravirt-ops debugging"
582 depends on PARAVIRT && DEBUG_KERNEL
584 Enable to debug paravirt_ops internals. Specifically, BUG if
585 a paravirt_op is missing when it is called.
589 bool "Disable Bootmem code"
591 Use early_res directly instead of bootmem before slab is ready.
592 - allocator (buddy) [generic]
593 - early allocator (bootmem) [generic]
594 - very early allocator (reserve_early*()) [x86]
595 - very very early allocator (early brk model) [x86]
596 So reduce one layer between early allocator to final allocator
602 This option adds a kernel parameter 'memtest', which allows memtest
604 memtest=0, mean disabled; -- default
605 memtest=1, mean do 1 test pattern;
607 memtest=4, mean do 4 test patterns.
608 If you are unsure how to answer this question, answer N.
610 config X86_SUMMIT_NUMA
612 depends on X86_32 && NUMA && X86_32_NON_STANDARD
614 config X86_CYCLONE_TIMER
616 depends on X86_32_NON_STANDARD
618 source "arch/x86/Kconfig.cpu"
622 prompt "HPET Timer Support" if X86_32
624 Use the IA-PC HPET (High Precision Event Timer) to manage
625 time in preference to the PIT and RTC, if a HPET is
627 HPET is the next generation timer replacing legacy 8254s.
628 The HPET provides a stable time base on SMP
629 systems, unlike the TSC, but it is more expensive to access,
630 as it is off-chip. You can find the HPET spec at
631 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
633 You can safely choose Y here. However, HPET will only be
634 activated if the platform and the BIOS support this feature.
635 Otherwise the 8254 will be used for timing services.
637 Choose N to continue using the legacy 8254 timer.
639 config HPET_EMULATE_RTC
641 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
645 prompt "Langwell APB Timer Support" if X86_MRST
647 APB timer is the replacement for 8254, HPET on X86 MID platforms.
648 The APBT provides a stable time base on SMP
649 systems, unlike the TSC, but it is more expensive to access,
650 as it is off-chip. APB timers are always running regardless of CPU
651 C states, they are used as per CPU clockevent device when possible.
653 # Mark as embedded because too many people got it wrong.
654 # The code disables itself when not needed.
657 bool "Enable DMI scanning" if EMBEDDED
659 Enabled scanning of DMI to identify machine quirks. Say Y
660 here unless you have verified that your setup is not
661 affected by entries in the DMI blacklist. Required by PNP
665 bool "GART IOMMU support" if EMBEDDED
668 depends on X86_64 && PCI && K8_NB
670 Support for full DMA access of devices with 32bit memory access only
671 on systems with more than 3GB. This is usually needed for USB,
672 sound, many IDE/SATA chipsets and some other devices.
673 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
674 based hardware IOMMU and a software bounce buffer based IOMMU used
675 on Intel systems and as fallback.
676 The code is only active when needed (enough memory and limited
677 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
681 bool "IBM Calgary IOMMU support"
683 depends on X86_64 && PCI && EXPERIMENTAL
685 Support for hardware IOMMUs in IBM's xSeries x366 and x460
686 systems. Needed to run systems with more than 3GB of memory
687 properly with 32-bit PCI devices that do not support DAC
688 (Double Address Cycle). Calgary also supports bus level
689 isolation, where all DMAs pass through the IOMMU. This
690 prevents them from going anywhere except their intended
691 destination. This catches hard-to-find kernel bugs and
692 mis-behaving drivers and devices that do not use the DMA-API
693 properly to set up their DMA buffers. The IOMMU can be
694 turned off at boot time with the iommu=off parameter.
695 Normally the kernel will make the right choice by itself.
698 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
700 prompt "Should Calgary be enabled by default?"
701 depends on CALGARY_IOMMU
703 Should Calgary be enabled by default? if you choose 'y', Calgary
704 will be used (if it exists). If you choose 'n', Calgary will not be
705 used even if it exists. If you choose 'n' and would like to use
706 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
710 bool "AMD IOMMU support"
713 depends on X86_64 && PCI && ACPI
715 With this option you can enable support for AMD IOMMU hardware in
716 your system. An IOMMU is a hardware component which provides
717 remapping of DMA memory accesses from devices. With an AMD IOMMU you
718 can isolate the the DMA memory of different devices and protect the
719 system from misbehaving device drivers or hardware.
721 You can find out if your system has an AMD IOMMU if you look into
722 your BIOS for an option to enable it or if you have an IVRS ACPI
725 config AMD_IOMMU_STATS
726 bool "Export AMD IOMMU statistics to debugfs"
730 This option enables code in the AMD IOMMU driver to collect various
731 statistics about whats happening in the driver and exports that
732 information to userspace via debugfs.
735 # need this always selected by IOMMU for the VIA workaround
739 Support for software bounce buffers used on x86-64 systems
740 which don't have a hardware IOMMU (e.g. the current generation
741 of Intel's x86-64 CPUs). Using this PCI devices which can only
742 access 32-bits of memory can be used on systems with more than
743 3 GB of memory. If unsure, say Y.
746 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
749 def_bool (AMD_IOMMU || DMAR)
752 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
753 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
754 select CPUMASK_OFFSTACK
757 Configure maximum number of CPUS and NUMA Nodes for this architecture.
761 int "Maximum number of CPUs" if SMP && !MAXSMP
762 range 2 8 if SMP && X86_32 && !X86_BIGSMP
763 range 2 512 if SMP && !MAXSMP
765 default "4096" if MAXSMP
766 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
769 This allows you to specify the maximum number of CPUs which this
770 kernel will support. The maximum supported value is 512 and the
771 minimum value which makes sense is 2.
773 This is purely to save memory - each supported CPU adds
774 approximately eight kilobytes to the kernel image.
777 bool "SMT (Hyperthreading) scheduler support"
780 SMT scheduler support improves the CPU scheduler's decision making
781 when dealing with Intel Pentium 4 chips with HyperThreading at a
782 cost of slightly increased overhead in some places. If unsure say
787 prompt "Multi-core scheduler support"
790 Multi-core scheduler support improves the CPU scheduler's decision
791 making when dealing with multi-core CPU chips at a cost of slightly
792 increased overhead in some places. If unsure say N here.
794 source "kernel/Kconfig.preempt"
797 bool "Local APIC support on uniprocessors"
798 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
800 A local APIC (Advanced Programmable Interrupt Controller) is an
801 integrated interrupt controller in the CPU. If you have a single-CPU
802 system which has a processor with a local APIC, you can say Y here to
803 enable and use it. If you say Y here even though your machine doesn't
804 have a local APIC, then the kernel will still run with no slowdown at
805 all. The local APIC supports CPU-generated self-interrupts (timer,
806 performance counters), and the NMI watchdog which detects hard
810 bool "IO-APIC support on uniprocessors"
811 depends on X86_UP_APIC
813 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
814 SMP-capable replacement for PC-style interrupt controllers. Most
815 SMP systems and many recent uniprocessor systems have one.
817 If you have a single-CPU system with an IO-APIC, you can say Y here
818 to use it. If you say Y here even though your machine doesn't have
819 an IO-APIC, then the kernel will still run with no slowdown at all.
821 config X86_LOCAL_APIC
823 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
827 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
829 config X86_VISWS_APIC
831 depends on X86_32 && X86_VISWS
833 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
834 bool "Reroute for broken boot IRQs"
836 depends on X86_IO_APIC
838 This option enables a workaround that fixes a source of
839 spurious interrupts. This is recommended when threaded
840 interrupt handling is used on systems where the generation of
841 superfluous "boot interrupts" cannot be disabled.
843 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
844 entry in the chipset's IO-APIC is masked (as, e.g. the RT
845 kernel does during interrupt handling). On chipsets where this
846 boot IRQ generation cannot be disabled, this workaround keeps
847 the original IRQ line masked so that only the equivalent "boot
848 IRQ" is delivered to the CPUs. The workaround also tells the
849 kernel to set up the IRQ handler on the boot IRQ line. In this
850 way only one interrupt is delivered to the kernel. Otherwise
851 the spurious second interrupt may cause the kernel to bring
852 down (vital) interrupt lines.
854 Only affects "broken" chipsets. Interrupt sharing may be
855 increased on these systems.
858 bool "Machine Check / overheating reporting"
860 Machine Check support allows the processor to notify the
861 kernel if it detects a problem (e.g. overheating, data corruption).
862 The action the kernel takes depends on the severity of the problem,
863 ranging from warning messages to halting the machine.
867 prompt "Intel MCE features"
868 depends on X86_MCE && X86_LOCAL_APIC
870 Additional support for intel specific MCE features such as
875 prompt "AMD MCE features"
876 depends on X86_MCE && X86_LOCAL_APIC
878 Additional support for AMD specific MCE features such as
879 the DRAM Error Threshold.
881 config X86_ANCIENT_MCE
883 depends on X86_32 && X86_MCE
884 prompt "Support for old Pentium 5 / WinChip machine checks"
886 Include support for machine check handling on old Pentium 5 or WinChip
887 systems. These typically need to be enabled explicitely on the command
890 config X86_MCE_THRESHOLD
891 depends on X86_MCE_AMD || X86_MCE_INTEL
895 config X86_MCE_INJECT
897 tristate "Machine check injector support"
899 Provide support for injecting machine checks for testing purposes.
900 If you don't know what a machine check is and you don't do kernel
901 QA it is safe to say n.
903 config X86_THERMAL_VECTOR
905 depends on X86_MCE_INTEL
908 bool "Enable VM86 support" if EMBEDDED
912 This option is required by programs like DOSEMU to run 16-bit legacy
913 code on X86 processors. It also may be needed by software like
914 XFree86 to initialize some video cards via BIOS. Disabling this
915 option saves about 6k.
918 tristate "Toshiba Laptop support"
921 This adds a driver to safely access the System Management Mode of
922 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
923 not work on models with a Phoenix BIOS. The System Management Mode
924 is used to set the BIOS and power saving options on Toshiba portables.
926 For information on utilities to make use of this driver see the
927 Toshiba Linux utilities web site at:
928 <http://www.buzzard.org.uk/toshiba/>.
930 Say Y if you intend to run this kernel on a Toshiba portable.
934 tristate "Dell laptop support"
936 This adds a driver to safely access the System Management Mode
937 of the CPU on the Dell Inspiron 8000. The System Management Mode
938 is used to read cpu temperature and cooling fan status and to
939 control the fans on the I8K portables.
941 This driver has been tested only on the Inspiron 8000 but it may
942 also work with other Dell laptops. You can force loading on other
943 models by passing the parameter `force=1' to the module. Use at
946 For information on utilities to make use of this driver see the
947 I8K Linux utilities web site at:
948 <http://people.debian.org/~dz/i8k/>
950 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
953 config X86_REBOOTFIXUPS
954 bool "Enable X86 board specific fixups for reboot"
957 This enables chipset and/or board specific fixups to be done
958 in order to get reboot to work correctly. This is only needed on
959 some combinations of hardware and BIOS. The symptom, for which
960 this config is intended, is when reboot ends with a stalled/hung
963 Currently, the only fixup is for the Geode machines using
964 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
966 Say Y if you want to enable the fixup. Currently, it's safe to
967 enable this option even if you don't need it.
971 tristate "/dev/cpu/microcode - microcode support"
974 If you say Y here, you will be able to update the microcode on
975 certain Intel and AMD processors. The Intel support is for the
976 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
977 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
978 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
979 You will obviously need the actual microcode binary data itself
980 which is not shipped with the Linux kernel.
982 This option selects the general module only, you need to select
983 at least one vendor specific module as well.
985 To compile this driver as a module, choose M here: the
986 module will be called microcode.
988 config MICROCODE_INTEL
989 bool "Intel microcode patch loading support"
994 This options enables microcode patch loading support for Intel
997 For latest news and information on obtaining all the required
998 Intel ingredients for this driver, check:
999 <http://www.urbanmyth.org/microcode/>.
1001 config MICROCODE_AMD
1002 bool "AMD microcode patch loading support"
1003 depends on MICROCODE
1006 If you select this option, microcode patch loading support for AMD
1007 processors will be enabled.
1009 config MICROCODE_OLD_INTERFACE
1011 depends on MICROCODE
1014 tristate "/dev/cpu/*/msr - Model-specific register support"
1016 This device gives privileged processes access to the x86
1017 Model-Specific Registers (MSRs). It is a character device with
1018 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1019 MSR accesses are directed to a specific CPU on multi-processor
1023 tristate "/dev/cpu/*/cpuid - CPU information support"
1025 This device gives processes access to the x86 CPUID instruction to
1026 be executed on a specific processor. It is a character device
1027 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1031 prompt "High Memory Support"
1032 default HIGHMEM4G if !X86_NUMAQ
1033 default HIGHMEM64G if X86_NUMAQ
1038 depends on !X86_NUMAQ
1040 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1041 However, the address space of 32-bit x86 processors is only 4
1042 Gigabytes large. That means that, if you have a large amount of
1043 physical memory, not all of it can be "permanently mapped" by the
1044 kernel. The physical memory that's not permanently mapped is called
1047 If you are compiling a kernel which will never run on a machine with
1048 more than 1 Gigabyte total physical RAM, answer "off" here (default
1049 choice and suitable for most users). This will result in a "3GB/1GB"
1050 split: 3GB are mapped so that each process sees a 3GB virtual memory
1051 space and the remaining part of the 4GB virtual memory space is used
1052 by the kernel to permanently map as much physical memory as
1055 If the machine has between 1 and 4 Gigabytes physical RAM, then
1058 If more than 4 Gigabytes is used then answer "64GB" here. This
1059 selection turns Intel PAE (Physical Address Extension) mode on.
1060 PAE implements 3-level paging on IA32 processors. PAE is fully
1061 supported by Linux, PAE mode is implemented on all recent Intel
1062 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1063 then the kernel will not boot on CPUs that don't support PAE!
1065 The actual amount of total physical memory will either be
1066 auto detected or can be forced by using a kernel command line option
1067 such as "mem=256M". (Try "man bootparam" or see the documentation of
1068 your boot loader (lilo or loadlin) about how to pass options to the
1069 kernel at boot time.)
1071 If unsure, say "off".
1075 depends on !X86_NUMAQ
1077 Select this if you have a 32-bit processor and between 1 and 4
1078 gigabytes of physical RAM.
1082 depends on !M386 && !M486
1085 Select this if you have a 32-bit processor and more than 4
1086 gigabytes of physical RAM.
1091 depends on EXPERIMENTAL
1092 prompt "Memory split" if EMBEDDED
1096 Select the desired split between kernel and user memory.
1098 If the address range available to the kernel is less than the
1099 physical memory installed, the remaining memory will be available
1100 as "high memory". Accessing high memory is a little more costly
1101 than low memory, as it needs to be mapped into the kernel first.
1102 Note that increasing the kernel address space limits the range
1103 available to user programs, making the address space there
1104 tighter. Selecting anything other than the default 3G/1G split
1105 will also likely make your kernel incompatible with binary-only
1108 If you are not absolutely sure what you are doing, leave this
1112 bool "3G/1G user/kernel split"
1113 config VMSPLIT_3G_OPT
1115 bool "3G/1G user/kernel split (for full 1G low memory)"
1117 bool "2G/2G user/kernel split"
1118 config VMSPLIT_2G_OPT
1120 bool "2G/2G user/kernel split (for full 2G low memory)"
1122 bool "1G/3G user/kernel split"
1127 default 0xB0000000 if VMSPLIT_3G_OPT
1128 default 0x80000000 if VMSPLIT_2G
1129 default 0x78000000 if VMSPLIT_2G_OPT
1130 default 0x40000000 if VMSPLIT_1G
1136 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1139 bool "PAE (Physical Address Extension) Support"
1140 depends on X86_32 && !HIGHMEM4G
1142 PAE is required for NX support, and furthermore enables
1143 larger swapspace support for non-overcommit purposes. It
1144 has the cost of more pagetable lookup overhead, and also
1145 consumes more pagetable space per process.
1147 config ARCH_PHYS_ADDR_T_64BIT
1148 def_bool X86_64 || X86_PAE
1150 config DIRECT_GBPAGES
1151 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1155 Allow the kernel linear mapping to use 1GB pages on CPUs that
1156 support it. This can improve the kernel's performance a tiny bit by
1157 reducing TLB pressure. If in doubt, say "Y".
1159 # Common NUMA Features
1161 bool "Numa Memory Allocation and Scheduler Support"
1163 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1164 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1166 Enable NUMA (Non Uniform Memory Access) support.
1168 The kernel will try to allocate memory used by a CPU on the
1169 local memory controller of the CPU and add some more
1170 NUMA awareness to the kernel.
1172 For 64-bit this is recommended if the system is Intel Core i7
1173 (or later), AMD Opteron, or EM64T NUMA.
1175 For 32-bit this is only needed on (rare) 32-bit-only platforms
1176 that support NUMA topologies, such as NUMAQ / Summit, or if you
1177 boot a 32-bit kernel on a 64-bit NUMA platform.
1179 Otherwise, you should say N.
1181 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1182 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1186 prompt "Old style AMD Opteron NUMA detection"
1187 depends on X86_64 && NUMA && PCI
1189 Enable K8 NUMA node topology detection. You should say Y here if
1190 you have a multi processor AMD K8 system. This uses an old
1191 method to read the NUMA configuration directly from the builtin
1192 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1193 instead, which also takes priority if both are compiled in.
1195 config X86_64_ACPI_NUMA
1197 prompt "ACPI NUMA detection"
1198 depends on X86_64 && NUMA && ACPI && PCI
1201 Enable ACPI SRAT based node topology detection.
1203 # Some NUMA nodes have memory ranges that span
1204 # other nodes. Even though a pfn is valid and
1205 # between a node's start and end pfns, it may not
1206 # reside on that node. See memmap_init_zone()
1208 config NODES_SPAN_OTHER_NODES
1210 depends on X86_64_ACPI_NUMA
1213 bool "NUMA emulation"
1214 depends on X86_64 && NUMA
1216 Enable NUMA emulation. A flat machine will be split
1217 into virtual nodes when booted with "numa=fake=N", where N is the
1218 number of nodes. This is only useful for debugging.
1221 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1223 default "9" if MAXSMP
1224 default "6" if X86_64
1225 default "4" if X86_NUMAQ
1227 depends on NEED_MULTIPLE_NODES
1229 Specify the maximum number of NUMA Nodes available on the target
1230 system. Increases memory reserved to accommodate various tables.
1232 config HAVE_ARCH_BOOTMEM
1234 depends on X86_32 && NUMA
1236 config ARCH_HAVE_MEMORY_PRESENT
1238 depends on X86_32 && DISCONTIGMEM
1240 config NEED_NODE_MEMMAP_SIZE
1242 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1244 config HAVE_ARCH_ALLOC_REMAP
1246 depends on X86_32 && NUMA
1248 config ARCH_FLATMEM_ENABLE
1250 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1252 config ARCH_DISCONTIGMEM_ENABLE
1254 depends on NUMA && X86_32
1256 config ARCH_DISCONTIGMEM_DEFAULT
1258 depends on NUMA && X86_32
1260 config ARCH_PROC_KCORE_TEXT
1262 depends on X86_64 && PROC_KCORE
1264 config ARCH_SPARSEMEM_DEFAULT
1268 config ARCH_SPARSEMEM_ENABLE
1270 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1271 select SPARSEMEM_STATIC if X86_32
1272 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1274 config ARCH_SELECT_MEMORY_MODEL
1276 depends on ARCH_SPARSEMEM_ENABLE
1278 config ARCH_MEMORY_PROBE
1280 depends on MEMORY_HOTPLUG
1282 config ILLEGAL_POINTER_VALUE
1285 default 0xdead000000000000 if X86_64
1290 bool "Allocate 3rd-level pagetables from highmem"
1291 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1293 The VM uses one page table entry for each page of physical memory.
1294 For systems with a lot of RAM, this can be wasteful of precious
1295 low memory. Setting this option will put user-space page table
1296 entries in high memory.
1298 config X86_CHECK_BIOS_CORRUPTION
1299 bool "Check for low memory corruption"
1301 Periodically check for memory corruption in low memory, which
1302 is suspected to be caused by BIOS. Even when enabled in the
1303 configuration, it is disabled at runtime. Enable it by
1304 setting "memory_corruption_check=1" on the kernel command
1305 line. By default it scans the low 64k of memory every 60
1306 seconds; see the memory_corruption_check_size and
1307 memory_corruption_check_period parameters in
1308 Documentation/kernel-parameters.txt to adjust this.
1310 When enabled with the default parameters, this option has
1311 almost no overhead, as it reserves a relatively small amount
1312 of memory and scans it infrequently. It both detects corruption
1313 and prevents it from affecting the running system.
1315 It is, however, intended as a diagnostic tool; if repeatable
1316 BIOS-originated corruption always affects the same memory,
1317 you can use memmap= to prevent the kernel from using that
1320 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1321 bool "Set the default setting of memory_corruption_check"
1322 depends on X86_CHECK_BIOS_CORRUPTION
1325 Set whether the default state of memory_corruption_check is
1328 config X86_RESERVE_LOW_64K
1329 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1332 Reserve the first 64K of physical RAM on BIOSes that are known
1333 to potentially corrupt that memory range. A numbers of BIOSes are
1334 known to utilize this area during suspend/resume, so it must not
1335 be used by the kernel.
1337 Set this to N if you are absolutely sure that you trust the BIOS
1338 to get all its memory reservations and usages right.
1340 If you have doubts about the BIOS (e.g. suspend/resume does not
1341 work or there's kernel crashes after certain hardware hotplug
1342 events) and it's not AMI or Phoenix, then you might want to enable
1343 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1344 corruption patterns.
1348 config MATH_EMULATION
1350 prompt "Math emulation" if X86_32
1352 Linux can emulate a math coprocessor (used for floating point
1353 operations) if you don't have one. 486DX and Pentium processors have
1354 a math coprocessor built in, 486SX and 386 do not, unless you added
1355 a 487DX or 387, respectively. (The messages during boot time can
1356 give you some hints here ["man dmesg"].) Everyone needs either a
1357 coprocessor or this emulation.
1359 If you don't have a math coprocessor, you need to say Y here; if you
1360 say Y here even though you have a coprocessor, the coprocessor will
1361 be used nevertheless. (This behavior can be changed with the kernel
1362 command line option "no387", which comes handy if your coprocessor
1363 is broken. Try "man bootparam" or see the documentation of your boot
1364 loader (lilo or loadlin) about how to pass options to the kernel at
1365 boot time.) This means that it is a good idea to say Y here if you
1366 intend to use this kernel on different machines.
1368 More information about the internals of the Linux math coprocessor
1369 emulation can be found in <file:arch/x86/math-emu/README>.
1371 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1372 kernel, it won't hurt.
1377 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1379 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1380 the Memory Type Range Registers (MTRRs) may be used to control
1381 processor access to memory ranges. This is most useful if you have
1382 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1383 allows bus write transfers to be combined into a larger transfer
1384 before bursting over the PCI/AGP bus. This can increase performance
1385 of image write operations 2.5 times or more. Saying Y here creates a
1386 /proc/mtrr file which may be used to manipulate your processor's
1387 MTRRs. Typically the X server should use this.
1389 This code has a reasonably generic interface so that similar
1390 control registers on other processors can be easily supported
1393 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1394 Registers (ARRs) which provide a similar functionality to MTRRs. For
1395 these, the ARRs are used to emulate the MTRRs.
1396 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1397 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1398 write-combining. All of these processors are supported by this code
1399 and it makes sense to say Y here if you have one of them.
1401 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1402 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1403 can lead to all sorts of problems, so it's good to say Y here.
1405 You can safely say Y even if your machine doesn't have MTRRs, you'll
1406 just add about 9 KB to your kernel.
1408 See <file:Documentation/x86/mtrr.txt> for more information.
1410 config MTRR_SANITIZER
1412 prompt "MTRR cleanup support"
1415 Convert MTRR layout from continuous to discrete, so X drivers can
1416 add writeback entries.
1418 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1419 The largest mtrr entry size for a continuous block can be set with
1424 config MTRR_SANITIZER_ENABLE_DEFAULT
1425 int "MTRR cleanup enable value (0-1)"
1428 depends on MTRR_SANITIZER
1430 Enable mtrr cleanup default value
1432 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1433 int "MTRR cleanup spare reg num (0-7)"
1436 depends on MTRR_SANITIZER
1438 mtrr cleanup spare entries default, it can be changed via
1439 mtrr_spare_reg_nr=N on the kernel command line.
1444 prompt "x86 PAT support" if EMBEDDED
1447 Use PAT attributes to setup page level cache control.
1449 PATs are the modern equivalents of MTRRs and are much more
1450 flexible than MTRRs.
1452 Say N here if you see bootup problems (boot crash, boot hang,
1453 spontaneous reboots) or a non-working video driver.
1457 config ARCH_USES_PG_UNCACHED
1462 bool "EFI runtime service support"
1465 This enables the kernel to use EFI runtime services that are
1466 available (such as the EFI variable services).
1468 This option is only useful on systems that have EFI firmware.
1469 In addition, you should use the latest ELILO loader available
1470 at <http://elilo.sourceforge.net> in order to take advantage
1471 of EFI runtime services. However, even with this option, the
1472 resultant kernel should continue to boot on existing non-EFI
1477 prompt "Enable seccomp to safely compute untrusted bytecode"
1479 This kernel feature is useful for number crunching applications
1480 that may need to compute untrusted bytecode during their
1481 execution. By using pipes or other transports made available to
1482 the process as file descriptors supporting the read/write
1483 syscalls, it's possible to isolate those applications in
1484 their own address space using seccomp. Once seccomp is
1485 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1486 and the task is only allowed to execute a few safe syscalls
1487 defined by each seccomp mode.
1489 If unsure, say Y. Only embedded should say N here.
1491 config CC_STACKPROTECTOR
1492 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1494 This option turns on the -fstack-protector GCC feature. This
1495 feature puts, at the beginning of functions, a canary value on
1496 the stack just before the return address, and validates
1497 the value just before actually returning. Stack based buffer
1498 overflows (that need to overwrite this return address) now also
1499 overwrite the canary, which gets detected and the attack is then
1500 neutralized via a kernel panic.
1502 This feature requires gcc version 4.2 or above, or a distribution
1503 gcc with the feature backported. Older versions are automatically
1504 detected and for those versions, this configuration option is
1505 ignored. (and a warning is printed during bootup)
1507 source kernel/Kconfig.hz
1510 bool "kexec system call"
1512 kexec is a system call that implements the ability to shutdown your
1513 current kernel, and to start another kernel. It is like a reboot
1514 but it is independent of the system firmware. And like a reboot
1515 you can start any kernel with it, not just Linux.
1517 The name comes from the similarity to the exec system call.
1519 It is an ongoing process to be certain the hardware in a machine
1520 is properly shutdown, so do not be surprised if this code does not
1521 initially work for you. It may help to enable device hotplugging
1522 support. As of this writing the exact hardware interface is
1523 strongly in flux, so no good recommendation can be made.
1526 bool "kernel crash dumps"
1527 depends on X86_64 || (X86_32 && HIGHMEM)
1529 Generate crash dump after being started by kexec.
1530 This should be normally only set in special crash dump kernels
1531 which are loaded in the main kernel with kexec-tools into
1532 a specially reserved region and then later executed after
1533 a crash by kdump/kexec. The crash dump kernel must be compiled
1534 to a memory address not used by the main kernel or BIOS using
1535 PHYSICAL_START, or it must be built as a relocatable image
1536 (CONFIG_RELOCATABLE=y).
1537 For more details see Documentation/kdump/kdump.txt
1540 bool "kexec jump (EXPERIMENTAL)"
1541 depends on EXPERIMENTAL
1542 depends on KEXEC && HIBERNATION
1544 Jump between original kernel and kexeced kernel and invoke
1545 code in physical address mode via KEXEC
1547 config PHYSICAL_START
1548 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1551 This gives the physical address where the kernel is loaded.
1553 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1554 bzImage will decompress itself to above physical address and
1555 run from there. Otherwise, bzImage will run from the address where
1556 it has been loaded by the boot loader and will ignore above physical
1559 In normal kdump cases one does not have to set/change this option
1560 as now bzImage can be compiled as a completely relocatable image
1561 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1562 address. This option is mainly useful for the folks who don't want
1563 to use a bzImage for capturing the crash dump and want to use a
1564 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1565 to be specifically compiled to run from a specific memory area
1566 (normally a reserved region) and this option comes handy.
1568 So if you are using bzImage for capturing the crash dump,
1569 leave the value here unchanged to 0x1000000 and set
1570 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1571 for capturing the crash dump change this value to start of
1572 the reserved region. In other words, it can be set based on
1573 the "X" value as specified in the "crashkernel=YM@XM"
1574 command line boot parameter passed to the panic-ed
1575 kernel. Please take a look at Documentation/kdump/kdump.txt
1576 for more details about crash dumps.
1578 Usage of bzImage for capturing the crash dump is recommended as
1579 one does not have to build two kernels. Same kernel can be used
1580 as production kernel and capture kernel. Above option should have
1581 gone away after relocatable bzImage support is introduced. But it
1582 is present because there are users out there who continue to use
1583 vmlinux for dump capture. This option should go away down the
1586 Don't change this unless you know what you are doing.
1589 bool "Build a relocatable kernel"
1592 This builds a kernel image that retains relocation information
1593 so it can be loaded someplace besides the default 1MB.
1594 The relocations tend to make the kernel binary about 10% larger,
1595 but are discarded at runtime.
1597 One use is for the kexec on panic case where the recovery kernel
1598 must live at a different physical address than the primary
1601 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1602 it has been loaded at and the compile time physical address
1603 (CONFIG_PHYSICAL_START) is ignored.
1605 # Relocation on x86-32 needs some additional build support
1606 config X86_NEED_RELOCS
1608 depends on X86_32 && RELOCATABLE
1610 config PHYSICAL_ALIGN
1612 prompt "Alignment value to which kernel should be aligned" if X86_32
1614 range 0x2000 0x1000000
1616 This value puts the alignment restrictions on physical address
1617 where kernel is loaded and run from. Kernel is compiled for an
1618 address which meets above alignment restriction.
1620 If bootloader loads the kernel at a non-aligned address and
1621 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1622 address aligned to above value and run from there.
1624 If bootloader loads the kernel at a non-aligned address and
1625 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1626 load address and decompress itself to the address it has been
1627 compiled for and run from there. The address for which kernel is
1628 compiled already meets above alignment restrictions. Hence the
1629 end result is that kernel runs from a physical address meeting
1630 above alignment restrictions.
1632 Don't change this unless you know what you are doing.
1635 bool "Support for hot-pluggable CPUs"
1636 depends on SMP && HOTPLUG
1638 Say Y here to allow turning CPUs off and on. CPUs can be
1639 controlled through /sys/devices/system/cpu.
1640 ( Note: power management support will enable this option
1641 automatically on SMP systems. )
1642 Say N if you want to disable CPU hotplug.
1646 prompt "Compat VDSO support"
1647 depends on X86_32 || IA32_EMULATION
1649 Map the 32-bit VDSO to the predictable old-style address too.
1651 Say N here if you are running a sufficiently recent glibc
1652 version (2.3.3 or later), to remove the high-mapped
1653 VDSO mapping and to exclusively use the randomized VDSO.
1658 bool "Built-in kernel command line"
1661 Allow for specifying boot arguments to the kernel at
1662 build time. On some systems (e.g. embedded ones), it is
1663 necessary or convenient to provide some or all of the
1664 kernel boot arguments with the kernel itself (that is,
1665 to not rely on the boot loader to provide them.)
1667 To compile command line arguments into the kernel,
1668 set this option to 'Y', then fill in the
1669 the boot arguments in CONFIG_CMDLINE.
1671 Systems with fully functional boot loaders (i.e. non-embedded)
1672 should leave this option set to 'N'.
1675 string "Built-in kernel command string"
1676 depends on CMDLINE_BOOL
1679 Enter arguments here that should be compiled into the kernel
1680 image and used at boot time. If the boot loader provides a
1681 command line at boot time, it is appended to this string to
1682 form the full kernel command line, when the system boots.
1684 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1685 change this behavior.
1687 In most cases, the command line (whether built-in or provided
1688 by the boot loader) should specify the device for the root
1691 config CMDLINE_OVERRIDE
1692 bool "Built-in command line overrides boot loader arguments"
1694 depends on CMDLINE_BOOL
1696 Set this option to 'Y' to have the kernel ignore the boot loader
1697 command line, and use ONLY the built-in command line.
1699 This is used to work around broken boot loaders. This should
1700 be set to 'N' under normal conditions.
1704 config ARCH_ENABLE_MEMORY_HOTPLUG
1706 depends on X86_64 || (X86_32 && HIGHMEM)
1708 config ARCH_ENABLE_MEMORY_HOTREMOVE
1710 depends on MEMORY_HOTPLUG
1712 config HAVE_ARCH_EARLY_PFN_TO_NID
1716 menu "Power management and ACPI options"
1718 config ARCH_HIBERNATION_HEADER
1720 depends on X86_64 && HIBERNATION
1722 source "kernel/power/Kconfig"
1724 source "drivers/acpi/Kconfig"
1726 source "drivers/sfi/Kconfig"
1731 depends on APM || APM_MODULE
1734 tristate "APM (Advanced Power Management) BIOS support"
1735 depends on X86_32 && PM_SLEEP
1737 APM is a BIOS specification for saving power using several different
1738 techniques. This is mostly useful for battery powered laptops with
1739 APM compliant BIOSes. If you say Y here, the system time will be
1740 reset after a RESUME operation, the /proc/apm device will provide
1741 battery status information, and user-space programs will receive
1742 notification of APM "events" (e.g. battery status change).
1744 If you select "Y" here, you can disable actual use of the APM
1745 BIOS by passing the "apm=off" option to the kernel at boot time.
1747 Note that the APM support is almost completely disabled for
1748 machines with more than one CPU.
1750 In order to use APM, you will need supporting software. For location
1751 and more information, read <file:Documentation/power/pm.txt> and the
1752 Battery Powered Linux mini-HOWTO, available from
1753 <http://www.tldp.org/docs.html#howto>.
1755 This driver does not spin down disk drives (see the hdparm(8)
1756 manpage ("man 8 hdparm") for that), and it doesn't turn off
1757 VESA-compliant "green" monitors.
1759 This driver does not support the TI 4000M TravelMate and the ACER
1760 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1761 desktop machines also don't have compliant BIOSes, and this driver
1762 may cause those machines to panic during the boot phase.
1764 Generally, if you don't have a battery in your machine, there isn't
1765 much point in using this driver and you should say N. If you get
1766 random kernel OOPSes or reboots that don't seem to be related to
1767 anything, try disabling/enabling this option (or disabling/enabling
1770 Some other things you should try when experiencing seemingly random,
1773 1) make sure that you have enough swap space and that it is
1775 2) pass the "no-hlt" option to the kernel
1776 3) switch on floating point emulation in the kernel and pass
1777 the "no387" option to the kernel
1778 4) pass the "floppy=nodma" option to the kernel
1779 5) pass the "mem=4M" option to the kernel (thereby disabling
1780 all but the first 4 MB of RAM)
1781 6) make sure that the CPU is not over clocked.
1782 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1783 8) disable the cache from your BIOS settings
1784 9) install a fan for the video card or exchange video RAM
1785 10) install a better fan for the CPU
1786 11) exchange RAM chips
1787 12) exchange the motherboard.
1789 To compile this driver as a module, choose M here: the
1790 module will be called apm.
1794 config APM_IGNORE_USER_SUSPEND
1795 bool "Ignore USER SUSPEND"
1797 This option will ignore USER SUSPEND requests. On machines with a
1798 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1799 series notebooks, it is necessary to say Y because of a BIOS bug.
1801 config APM_DO_ENABLE
1802 bool "Enable PM at boot time"
1804 Enable APM features at boot time. From page 36 of the APM BIOS
1805 specification: "When disabled, the APM BIOS does not automatically
1806 power manage devices, enter the Standby State, enter the Suspend
1807 State, or take power saving steps in response to CPU Idle calls."
1808 This driver will make CPU Idle calls when Linux is idle (unless this
1809 feature is turned off -- see "Do CPU IDLE calls", below). This
1810 should always save battery power, but more complicated APM features
1811 will be dependent on your BIOS implementation. You may need to turn
1812 this option off if your computer hangs at boot time when using APM
1813 support, or if it beeps continuously instead of suspending. Turn
1814 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1815 T400CDT. This is off by default since most machines do fine without
1819 bool "Make CPU Idle calls when idle"
1821 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1822 On some machines, this can activate improved power savings, such as
1823 a slowed CPU clock rate, when the machine is idle. These idle calls
1824 are made after the idle loop has run for some length of time (e.g.,
1825 333 mS). On some machines, this will cause a hang at boot time or
1826 whenever the CPU becomes idle. (On machines with more than one CPU,
1827 this option does nothing.)
1829 config APM_DISPLAY_BLANK
1830 bool "Enable console blanking using APM"
1832 Enable console blanking using the APM. Some laptops can use this to
1833 turn off the LCD backlight when the screen blanker of the Linux
1834 virtual console blanks the screen. Note that this is only used by
1835 the virtual console screen blanker, and won't turn off the backlight
1836 when using the X Window system. This also doesn't have anything to
1837 do with your VESA-compliant power-saving monitor. Further, this
1838 option doesn't work for all laptops -- it might not turn off your
1839 backlight at all, or it might print a lot of errors to the console,
1840 especially if you are using gpm.
1842 config APM_ALLOW_INTS
1843 bool "Allow interrupts during APM BIOS calls"
1845 Normally we disable external interrupts while we are making calls to
1846 the APM BIOS as a measure to lessen the effects of a badly behaving
1847 BIOS implementation. The BIOS should reenable interrupts if it
1848 needs to. Unfortunately, some BIOSes do not -- especially those in
1849 many of the newer IBM Thinkpads. If you experience hangs when you
1850 suspend, try setting this to Y. Otherwise, say N.
1854 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1856 source "drivers/cpuidle/Kconfig"
1858 source "drivers/idle/Kconfig"
1863 menu "Bus options (PCI etc.)"
1868 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1870 Find out whether you have a PCI motherboard. PCI is the name of a
1871 bus system, i.e. the way the CPU talks to the other stuff inside
1872 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1873 VESA. If you have PCI, say Y, otherwise N.
1876 prompt "PCI access mode"
1877 depends on X86_32 && PCI
1880 On PCI systems, the BIOS can be used to detect the PCI devices and
1881 determine their configuration. However, some old PCI motherboards
1882 have BIOS bugs and may crash if this is done. Also, some embedded
1883 PCI-based systems don't have any BIOS at all. Linux can also try to
1884 detect the PCI hardware directly without using the BIOS.
1886 With this option, you can specify how Linux should detect the
1887 PCI devices. If you choose "BIOS", the BIOS will be used,
1888 if you choose "Direct", the BIOS won't be used, and if you
1889 choose "MMConfig", then PCI Express MMCONFIG will be used.
1890 If you choose "Any", the kernel will try MMCONFIG, then the
1891 direct access method and falls back to the BIOS if that doesn't
1892 work. If unsure, go with the default, which is "Any".
1897 config PCI_GOMMCONFIG
1914 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1916 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1919 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1923 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1927 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1934 bool "Support mmconfig PCI config space access"
1935 depends on X86_64 && PCI && ACPI
1938 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1939 depends on PCI_MSI && ACPI && EXPERIMENTAL
1941 DMA remapping (DMAR) devices support enables independent address
1942 translations for Direct Memory Access (DMA) from devices.
1943 These DMA remapping devices are reported via ACPI tables
1944 and include PCI device scope covered by these DMA
1947 config DMAR_DEFAULT_ON
1949 prompt "Enable DMA Remapping Devices by default"
1952 Selecting this option will enable a DMAR device at boot time if
1953 one is found. If this option is not selected, DMAR support can
1954 be enabled by passing intel_iommu=on to the kernel. It is
1955 recommended you say N here while the DMAR code remains
1958 config DMAR_BROKEN_GFX_WA
1960 prompt "Workaround broken graphics drivers (going away soon)"
1961 depends on DMAR && BROKEN
1963 Current Graphics drivers tend to use physical address
1964 for DMA and avoid using DMA APIs. Setting this config
1965 option permits the IOMMU driver to set a unity map for
1966 all the OS-visible memory. Hence the driver can continue
1967 to use physical addresses for DMA, at least until this
1968 option is removed in the 2.6.32 kernel.
1970 config DMAR_FLOPPY_WA
1974 Floppy disk drivers are known to bypass DMA API calls
1975 thereby failing to work when IOMMU is enabled. This
1976 workaround will setup a 1:1 mapping for the first
1977 16MiB to make floppy (an ISA device) work.
1980 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1981 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1983 Supports Interrupt remapping for IO-APIC and MSI devices.
1984 To use x2apic mode in the CPU's which support x2APIC enhancements or
1985 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1987 source "drivers/pci/pcie/Kconfig"
1989 source "drivers/pci/Kconfig"
1991 # x86_64 have no ISA slots, but do have ISA-style DMA.
2000 Find out whether you have ISA slots on your motherboard. ISA is the
2001 name of a bus system, i.e. the way the CPU talks to the other stuff
2002 inside your box. Other bus systems are PCI, EISA, MicroChannel
2003 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2004 newer boards don't support it. If you have ISA, say Y, otherwise N.
2010 The Extended Industry Standard Architecture (EISA) bus was
2011 developed as an open alternative to the IBM MicroChannel bus.
2013 The EISA bus provided some of the features of the IBM MicroChannel
2014 bus while maintaining backward compatibility with cards made for
2015 the older ISA bus. The EISA bus saw limited use between 1988 and
2016 1995 when it was made obsolete by the PCI bus.
2018 Say Y here if you are building a kernel for an EISA-based machine.
2022 source "drivers/eisa/Kconfig"
2027 MicroChannel Architecture is found in some IBM PS/2 machines and
2028 laptops. It is a bus system similar to PCI or ISA. See
2029 <file:Documentation/mca.txt> (and especially the web page given
2030 there) before attempting to build an MCA bus kernel.
2032 source "drivers/mca/Kconfig"
2035 tristate "NatSemi SCx200 support"
2037 This provides basic support for National Semiconductor's
2038 (now AMD's) Geode processors. The driver probes for the
2039 PCI-IDs of several on-chip devices, so its a good dependency
2040 for other scx200_* drivers.
2042 If compiled as a module, the driver is named scx200.
2044 config SCx200HR_TIMER
2045 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2046 depends on SCx200 && GENERIC_TIME
2049 This driver provides a clocksource built upon the on-chip
2050 27MHz high-resolution timer. Its also a workaround for
2051 NSC Geode SC-1100's buggy TSC, which loses time when the
2052 processor goes idle (as is done by the scheduler). The
2053 other workaround is idle=poll boot option.
2056 bool "One Laptop Per Child support"
2060 Add support for detecting the unique features of the OLPC
2067 depends on CPU_SUP_AMD && PCI
2069 source "drivers/pcmcia/Kconfig"
2071 source "drivers/pci/hotplug/Kconfig"
2076 menu "Executable file formats / Emulations"
2078 source "fs/Kconfig.binfmt"
2080 config IA32_EMULATION
2081 bool "IA32 Emulation"
2083 select COMPAT_BINFMT_ELF
2085 Include code to run 32-bit programs under a 64-bit kernel. You should
2086 likely turn this on, unless you're 100% sure that you don't have any
2087 32-bit programs left.
2090 tristate "IA32 a.out support"
2091 depends on IA32_EMULATION
2093 Support old a.out binaries in the 32bit emulation.
2097 depends on IA32_EMULATION
2099 config COMPAT_FOR_U64_ALIGNMENT
2103 config SYSVIPC_COMPAT
2105 depends on COMPAT && SYSVIPC
2110 config HAVE_ATOMIC_IOMAP
2114 source "net/Kconfig"
2116 source "drivers/Kconfig"
2118 source "drivers/firmware/Kconfig"
2122 source "arch/x86/Kconfig.debug"
2124 source "security/Kconfig"
2126 source "crypto/Kconfig"
2128 source "arch/x86/kvm/Kconfig"
2130 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob