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
63 default "elf32-i386" if X86_32
64 default "elf64-x86-64" if X86_64
68 default "arch/x86/configs/i386_defconfig" if X86_32
69 default "arch/x86/configs/x86_64_defconfig" if X86_64
74 config GENERIC_CMOS_UPDATE
77 config CLOCKSOURCE_WATCHDOG
80 config GENERIC_CLOCKEVENTS
83 config GENERIC_CLOCKEVENTS_BROADCAST
85 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
87 config LOCKDEP_SUPPORT
90 config STACKTRACE_SUPPORT
93 config HAVE_LATENCYTOP_SUPPORT
105 config NEED_DMA_MAP_STATE
106 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
108 config GENERIC_ISA_DMA
117 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
119 config GENERIC_BUG_RELATIVE_POINTERS
122 config GENERIC_HWEIGHT
128 config ARCH_MAY_HAVE_PC_FDC
131 config RWSEM_GENERIC_SPINLOCK
134 config RWSEM_XCHGADD_ALGORITHM
137 config ARCH_HAS_CPU_IDLE_WAIT
140 config GENERIC_CALIBRATE_DELAY
143 config GENERIC_TIME_VSYSCALL
147 config ARCH_HAS_CPU_RELAX
150 config ARCH_HAS_DEFAULT_IDLE
153 config ARCH_HAS_CACHE_LINE_SIZE
156 config HAVE_SETUP_PER_CPU_AREA
159 config NEED_PER_CPU_EMBED_FIRST_CHUNK
162 config NEED_PER_CPU_PAGE_FIRST_CHUNK
165 config HAVE_CPUMASK_OF_CPU_MAP
168 config ARCH_HIBERNATION_POSSIBLE
171 config ARCH_SUSPEND_POSSIBLE
178 config ARCH_POPULATES_NODE_MAP
185 config ARCH_SUPPORTS_OPTIMIZED_INLINING
188 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
191 config HAVE_EARLY_RES
194 config HAVE_INTEL_TXT
196 depends on EXPERIMENTAL && DMAR && ACPI
198 # Use the generic interrupt handling code in kernel/irq/:
199 config GENERIC_HARDIRQS
203 config GENERIC_HARDIRQS_NO__DO_IRQ
206 config GENERIC_IRQ_PROBE
210 config GENERIC_PENDING_IRQ
212 depends on GENERIC_HARDIRQS && SMP
215 config USE_GENERIC_SMP_HELPERS
221 depends on X86_32 && SMP
225 depends on X86_64 && SMP
232 config X86_TRAMPOLINE
234 depends on SMP || (64BIT && ACPI_SLEEP)
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
244 config ARCH_CPU_PROBE_RELEASE
246 depends on HOTPLUG_CPU
248 source "init/Kconfig"
249 source "kernel/Kconfig.freezer"
251 menu "Processor type and features"
253 source "kernel/time/Kconfig"
256 bool "Symmetric multi-processing support"
258 This enables support for systems with more than one CPU. If you have
259 a system with only one CPU, like most personal computers, say N. If
260 you have a system with more than one CPU, say Y.
262 If you say N here, the kernel will run on single and multiprocessor
263 machines, but will use only one CPU of a multiprocessor machine. If
264 you say Y here, the kernel will run on many, but not all,
265 singleprocessor machines. On a singleprocessor machine, the kernel
266 will run faster if you say N here.
268 Note that if you say Y here and choose architecture "586" or
269 "Pentium" under "Processor family", the kernel will not work on 486
270 architectures. Similarly, multiprocessor kernels for the "PPro"
271 architecture may not work on all Pentium based boards.
273 People using multiprocessor machines who say Y here should also say
274 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
275 Management" code will be disabled if you say Y here.
277 See also <file:Documentation/i386/IO-APIC.txt>,
278 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
279 <http://www.tldp.org/docs.html#howto>.
281 If you don't know what to do here, say N.
284 bool "Support x2apic"
285 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
287 This enables x2apic support on CPUs that have this feature.
289 This allows 32-bit apic IDs (so it can support very large systems),
290 and accesses the local apic via MSRs not via mmio.
292 If you don't know what to do here, say N.
295 bool "Support sparse irq numbering"
296 depends on PCI_MSI || HT_IRQ
298 This enables support for sparse irqs. This is useful for distro
299 kernels that want to define a high CONFIG_NR_CPUS value but still
300 want to have low kernel memory footprint on smaller machines.
302 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
303 out the irq_desc[] array in a more NUMA-friendly way. )
305 If you don't know what to do here, say N.
309 depends on SPARSE_IRQ && NUMA
312 bool "Enable MPS table" if ACPI
314 depends on X86_LOCAL_APIC
316 For old smp systems that do not have proper acpi support. Newer systems
317 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
320 bool "Support for big SMP systems with more than 8 CPUs"
321 depends on X86_32 && SMP
323 This option is needed for the systems that have more than 8 CPUs
326 config X86_EXTENDED_PLATFORM
327 bool "Support for extended (non-PC) x86 platforms"
330 If you disable this option then the kernel will only support
331 standard PC platforms. (which covers the vast majority of
334 If you enable this option then you'll be able to select support
335 for the following (non-PC) 32 bit x86 platforms:
339 SGI 320/540 (Visual Workstation)
340 Summit/EXA (IBM x440)
341 Unisys ES7000 IA32 series
342 Moorestown MID devices
344 If you have one of these systems, or if you want to build a
345 generic distribution kernel, say Y here - otherwise say N.
349 config X86_EXTENDED_PLATFORM
350 bool "Support for extended (non-PC) x86 platforms"
353 If you disable this option then the kernel will only support
354 standard PC platforms. (which covers the vast majority of
357 If you enable this option then you'll be able to select support
358 for the following (non-PC) 64 bit x86 platforms:
362 If you have one of these systems, or if you want to build a
363 generic distribution kernel, say Y here - otherwise say N.
365 # This is an alphabetically sorted list of 64 bit extended platforms
366 # Please maintain the alphabetic order if and when there are additions
371 depends on X86_64 && PCI
372 depends on X86_EXTENDED_PLATFORM
374 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
375 supposed to run on these EM64T-based machines. Only choose this option
376 if you have one of these machines.
379 bool "SGI Ultraviolet"
381 depends on X86_EXTENDED_PLATFORM
383 depends on X86_X2APIC
385 This option is needed in order to support SGI Ultraviolet systems.
386 If you don't have one of these, you should say N here.
388 # Following is an alphabetically sorted list of 32 bit extended platforms
389 # Please maintain the alphabetic order if and when there are additions
394 depends on X86_EXTENDED_PLATFORM
396 Select this for an AMD Elan processor.
398 Do not use this option for K6/Athlon/Opteron processors!
400 If unsure, choose "PC-compatible" instead.
403 bool "Moorestown MID platform"
407 depends on X86_EXTENDED_PLATFORM
408 depends on X86_IO_APIC
411 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
412 Internet Device(MID) platform. Moorestown consists of two chips:
413 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
414 Unlike standard x86 PCs, Moorestown does not have many legacy devices
415 nor standard legacy replacement devices/features. e.g. Moorestown does
416 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
419 bool "RDC R-321x SoC"
421 depends on X86_EXTENDED_PLATFORM
423 select X86_REBOOTFIXUPS
425 This option is needed for RDC R-321x system-on-chip, also known
427 If you don't have one of these chips, you should say N here.
429 config X86_32_NON_STANDARD
430 bool "Support non-standard 32-bit SMP architectures"
431 depends on X86_32 && SMP
432 depends on X86_EXTENDED_PLATFORM
434 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
435 subarchitectures. It is intended for a generic binary kernel.
436 if you select them all, kernel will probe it one by one. and will
439 # Alphabetically sorted list of Non standard 32 bit platforms
442 bool "NUMAQ (IBM/Sequent)"
443 depends on X86_32_NON_STANDARD
448 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
449 NUMA multiquad box. This changes the way that processors are
450 bootstrapped, and uses Clustered Logical APIC addressing mode instead
451 of Flat Logical. You will need a new lynxer.elf file to flash your
452 firmware with - send email to <Martin.Bligh@us.ibm.com>.
454 config X86_SUPPORTS_MEMORY_FAILURE
456 # MCE code calls memory_failure():
458 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
459 depends on !X86_NUMAQ
460 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
461 depends on X86_64 || !SPARSEMEM
462 select ARCH_SUPPORTS_MEMORY_FAILURE
466 bool "SGI 320/540 (Visual Workstation)"
467 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
468 depends on X86_32_NON_STANDARD
470 The SGI Visual Workstation series is an IA32-based workstation
471 based on SGI systems chips with some legacy PC hardware attached.
473 Say Y here to create a kernel to run on the SGI 320 or 540.
475 A kernel compiled for the Visual Workstation will run on general
476 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
479 bool "Summit/EXA (IBM x440)"
480 depends on X86_32_NON_STANDARD
482 This option is needed for IBM systems that use the Summit/EXA chipset.
483 In particular, it is needed for the x440.
486 bool "Unisys ES7000 IA32 series"
487 depends on X86_32_NON_STANDARD && X86_BIGSMP
489 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
490 supposed to run on an IA32-based Unisys ES7000 system.
492 config SCHED_OMIT_FRAME_POINTER
494 prompt "Single-depth WCHAN output"
497 Calculate simpler /proc/<PID>/wchan values. If this option
498 is disabled then wchan values will recurse back to the
499 caller function. This provides more accurate wchan values,
500 at the expense of slightly more scheduling overhead.
502 If in doubt, say "Y".
504 menuconfig PARAVIRT_GUEST
505 bool "Paravirtualized guest support"
507 Say Y here to get to see options related to running Linux under
508 various hypervisors. This option alone does not add any kernel code.
510 If you say N, all options in this submenu will be skipped and disabled.
514 source "arch/x86/xen/Kconfig"
517 bool "VMI Guest support (DEPRECATED)"
521 VMI provides a paravirtualized interface to the VMware ESX server
522 (it could be used by other hypervisors in theory too, but is not
523 at the moment), by linking the kernel to a GPL-ed ROM module
524 provided by the hypervisor.
526 As of September 2009, VMware has started a phased retirement
527 of this feature from VMware's products. Please see
528 feature-removal-schedule.txt for details. If you are
529 planning to enable this option, please note that you cannot
530 live migrate a VMI enabled VM to a future VMware product,
531 which doesn't support VMI. So if you expect your kernel to
532 seamlessly migrate to newer VMware products, keep this
536 bool "KVM paravirtualized clock"
538 select PARAVIRT_CLOCK
540 Turning on this option will allow you to run a paravirtualized clock
541 when running over the KVM hypervisor. Instead of relying on a PIT
542 (or probably other) emulation by the underlying device model, the host
543 provides the guest with timing infrastructure such as time of day, and
547 bool "KVM Guest support"
550 This option enables various optimizations for running under the KVM
553 source "arch/x86/lguest/Kconfig"
556 bool "Enable paravirtualization code"
558 This changes the kernel so it can modify itself when it is run
559 under a hypervisor, potentially improving performance significantly
560 over full virtualization. However, when run without a hypervisor
561 the kernel is theoretically slower and slightly larger.
563 config PARAVIRT_SPINLOCKS
564 bool "Paravirtualization layer for spinlocks"
565 depends on PARAVIRT && SMP && EXPERIMENTAL
567 Paravirtualized spinlocks allow a pvops backend to replace the
568 spinlock implementation with something virtualization-friendly
569 (for example, block the virtual CPU rather than spinning).
571 Unfortunately the downside is an up to 5% performance hit on
572 native kernels, with various workloads.
574 If you are unsure how to answer this question, answer N.
576 config PARAVIRT_CLOCK
582 config PARAVIRT_DEBUG
583 bool "paravirt-ops debugging"
584 depends on PARAVIRT && DEBUG_KERNEL
586 Enable to debug paravirt_ops internals. Specifically, BUG if
587 a paravirt_op is missing when it is called.
591 bool "Disable Bootmem code"
593 Use early_res directly instead of bootmem before slab is ready.
594 - allocator (buddy) [generic]
595 - early allocator (bootmem) [generic]
596 - very early allocator (reserve_early*()) [x86]
597 - very very early allocator (early brk model) [x86]
598 So reduce one layer between early allocator to final allocator
604 This option adds a kernel parameter 'memtest', which allows memtest
606 memtest=0, mean disabled; -- default
607 memtest=1, mean do 1 test pattern;
609 memtest=4, mean do 4 test patterns.
610 If you are unsure how to answer this question, answer N.
612 config X86_SUMMIT_NUMA
614 depends on X86_32 && NUMA && X86_32_NON_STANDARD
616 config X86_CYCLONE_TIMER
618 depends on X86_32_NON_STANDARD
620 source "arch/x86/Kconfig.cpu"
624 prompt "HPET Timer Support" if X86_32
626 Use the IA-PC HPET (High Precision Event Timer) to manage
627 time in preference to the PIT and RTC, if a HPET is
629 HPET is the next generation timer replacing legacy 8254s.
630 The HPET provides a stable time base on SMP
631 systems, unlike the TSC, but it is more expensive to access,
632 as it is off-chip. You can find the HPET spec at
633 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
635 You can safely choose Y here. However, HPET will only be
636 activated if the platform and the BIOS support this feature.
637 Otherwise the 8254 will be used for timing services.
639 Choose N to continue using the legacy 8254 timer.
641 config HPET_EMULATE_RTC
643 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
647 prompt "Langwell APB Timer Support" if X86_MRST
649 APB timer is the replacement for 8254, HPET on X86 MID platforms.
650 The APBT provides a stable time base on SMP
651 systems, unlike the TSC, but it is more expensive to access,
652 as it is off-chip. APB timers are always running regardless of CPU
653 C states, they are used as per CPU clockevent device when possible.
655 # Mark as embedded because too many people got it wrong.
656 # The code disables itself when not needed.
659 bool "Enable DMI scanning" if EMBEDDED
661 Enabled scanning of DMI to identify machine quirks. Say Y
662 here unless you have verified that your setup is not
663 affected by entries in the DMI blacklist. Required by PNP
667 bool "GART IOMMU support" if EMBEDDED
670 depends on X86_64 && PCI && K8_NB
672 Support for full DMA access of devices with 32bit memory access only
673 on systems with more than 3GB. This is usually needed for USB,
674 sound, many IDE/SATA chipsets and some other devices.
675 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
676 based hardware IOMMU and a software bounce buffer based IOMMU used
677 on Intel systems and as fallback.
678 The code is only active when needed (enough memory and limited
679 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
683 bool "IBM Calgary IOMMU support"
685 depends on X86_64 && PCI && EXPERIMENTAL
687 Support for hardware IOMMUs in IBM's xSeries x366 and x460
688 systems. Needed to run systems with more than 3GB of memory
689 properly with 32-bit PCI devices that do not support DAC
690 (Double Address Cycle). Calgary also supports bus level
691 isolation, where all DMAs pass through the IOMMU. This
692 prevents them from going anywhere except their intended
693 destination. This catches hard-to-find kernel bugs and
694 mis-behaving drivers and devices that do not use the DMA-API
695 properly to set up their DMA buffers. The IOMMU can be
696 turned off at boot time with the iommu=off parameter.
697 Normally the kernel will make the right choice by itself.
700 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
702 prompt "Should Calgary be enabled by default?"
703 depends on CALGARY_IOMMU
705 Should Calgary be enabled by default? if you choose 'y', Calgary
706 will be used (if it exists). If you choose 'n', Calgary will not be
707 used even if it exists. If you choose 'n' and would like to use
708 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
712 bool "AMD IOMMU support"
715 depends on X86_64 && PCI && ACPI
717 With this option you can enable support for AMD IOMMU hardware in
718 your system. An IOMMU is a hardware component which provides
719 remapping of DMA memory accesses from devices. With an AMD IOMMU you
720 can isolate the the DMA memory of different devices and protect the
721 system from misbehaving device drivers or hardware.
723 You can find out if your system has an AMD IOMMU if you look into
724 your BIOS for an option to enable it or if you have an IVRS ACPI
727 config AMD_IOMMU_STATS
728 bool "Export AMD IOMMU statistics to debugfs"
732 This option enables code in the AMD IOMMU driver to collect various
733 statistics about whats happening in the driver and exports that
734 information to userspace via debugfs.
737 # need this always selected by IOMMU for the VIA workaround
741 Support for software bounce buffers used on x86-64 systems
742 which don't have a hardware IOMMU (e.g. the current generation
743 of Intel's x86-64 CPUs). Using this PCI devices which can only
744 access 32-bits of memory can be used on systems with more than
745 3 GB of memory. If unsure, say Y.
748 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
751 def_bool (AMD_IOMMU || DMAR)
754 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
755 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
756 select CPUMASK_OFFSTACK
759 Configure maximum number of CPUS and NUMA Nodes for this architecture.
763 int "Maximum number of CPUs" if SMP && !MAXSMP
764 range 2 8 if SMP && X86_32 && !X86_BIGSMP
765 range 2 512 if SMP && !MAXSMP
767 default "4096" if MAXSMP
768 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
771 This allows you to specify the maximum number of CPUs which this
772 kernel will support. The maximum supported value is 512 and the
773 minimum value which makes sense is 2.
775 This is purely to save memory - each supported CPU adds
776 approximately eight kilobytes to the kernel image.
779 bool "SMT (Hyperthreading) scheduler support"
782 SMT scheduler support improves the CPU scheduler's decision making
783 when dealing with Intel Pentium 4 chips with HyperThreading at a
784 cost of slightly increased overhead in some places. If unsure say
789 prompt "Multi-core scheduler support"
792 Multi-core scheduler support improves the CPU scheduler's decision
793 making when dealing with multi-core CPU chips at a cost of slightly
794 increased overhead in some places. If unsure say N here.
796 source "kernel/Kconfig.preempt"
799 bool "Local APIC support on uniprocessors"
800 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
802 A local APIC (Advanced Programmable Interrupt Controller) is an
803 integrated interrupt controller in the CPU. If you have a single-CPU
804 system which has a processor with a local APIC, you can say Y here to
805 enable and use it. If you say Y here even though your machine doesn't
806 have a local APIC, then the kernel will still run with no slowdown at
807 all. The local APIC supports CPU-generated self-interrupts (timer,
808 performance counters), and the NMI watchdog which detects hard
812 bool "IO-APIC support on uniprocessors"
813 depends on X86_UP_APIC
815 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
816 SMP-capable replacement for PC-style interrupt controllers. Most
817 SMP systems and many recent uniprocessor systems have one.
819 If you have a single-CPU system with an IO-APIC, you can say Y here
820 to use it. If you say Y here even though your machine doesn't have
821 an IO-APIC, then the kernel will still run with no slowdown at all.
823 config X86_LOCAL_APIC
825 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
829 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
831 config X86_VISWS_APIC
833 depends on X86_32 && X86_VISWS
835 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
836 bool "Reroute for broken boot IRQs"
838 depends on X86_IO_APIC
840 This option enables a workaround that fixes a source of
841 spurious interrupts. This is recommended when threaded
842 interrupt handling is used on systems where the generation of
843 superfluous "boot interrupts" cannot be disabled.
845 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
846 entry in the chipset's IO-APIC is masked (as, e.g. the RT
847 kernel does during interrupt handling). On chipsets where this
848 boot IRQ generation cannot be disabled, this workaround keeps
849 the original IRQ line masked so that only the equivalent "boot
850 IRQ" is delivered to the CPUs. The workaround also tells the
851 kernel to set up the IRQ handler on the boot IRQ line. In this
852 way only one interrupt is delivered to the kernel. Otherwise
853 the spurious second interrupt may cause the kernel to bring
854 down (vital) interrupt lines.
856 Only affects "broken" chipsets. Interrupt sharing may be
857 increased on these systems.
860 bool "Machine Check / overheating reporting"
862 Machine Check support allows the processor to notify the
863 kernel if it detects a problem (e.g. overheating, data corruption).
864 The action the kernel takes depends on the severity of the problem,
865 ranging from warning messages to halting the machine.
869 prompt "Intel MCE features"
870 depends on X86_MCE && X86_LOCAL_APIC
872 Additional support for intel specific MCE features such as
877 prompt "AMD MCE features"
878 depends on X86_MCE && X86_LOCAL_APIC
880 Additional support for AMD specific MCE features such as
881 the DRAM Error Threshold.
883 config X86_ANCIENT_MCE
885 depends on X86_32 && X86_MCE
886 prompt "Support for old Pentium 5 / WinChip machine checks"
888 Include support for machine check handling on old Pentium 5 or WinChip
889 systems. These typically need to be enabled explicitely on the command
892 config X86_MCE_THRESHOLD
893 depends on X86_MCE_AMD || X86_MCE_INTEL
897 config X86_MCE_INJECT
899 tristate "Machine check injector support"
901 Provide support for injecting machine checks for testing purposes.
902 If you don't know what a machine check is and you don't do kernel
903 QA it is safe to say n.
905 config X86_THERMAL_VECTOR
907 depends on X86_MCE_INTEL
910 bool "Enable VM86 support" if EMBEDDED
914 This option is required by programs like DOSEMU to run 16-bit legacy
915 code on X86 processors. It also may be needed by software like
916 XFree86 to initialize some video cards via BIOS. Disabling this
917 option saves about 6k.
920 tristate "Toshiba Laptop support"
923 This adds a driver to safely access the System Management Mode of
924 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
925 not work on models with a Phoenix BIOS. The System Management Mode
926 is used to set the BIOS and power saving options on Toshiba portables.
928 For information on utilities to make use of this driver see the
929 Toshiba Linux utilities web site at:
930 <http://www.buzzard.org.uk/toshiba/>.
932 Say Y if you intend to run this kernel on a Toshiba portable.
936 tristate "Dell laptop support"
938 This adds a driver to safely access the System Management Mode
939 of the CPU on the Dell Inspiron 8000. The System Management Mode
940 is used to read cpu temperature and cooling fan status and to
941 control the fans on the I8K portables.
943 This driver has been tested only on the Inspiron 8000 but it may
944 also work with other Dell laptops. You can force loading on other
945 models by passing the parameter `force=1' to the module. Use at
948 For information on utilities to make use of this driver see the
949 I8K Linux utilities web site at:
950 <http://people.debian.org/~dz/i8k/>
952 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
955 config X86_REBOOTFIXUPS
956 bool "Enable X86 board specific fixups for reboot"
959 This enables chipset and/or board specific fixups to be done
960 in order to get reboot to work correctly. This is only needed on
961 some combinations of hardware and BIOS. The symptom, for which
962 this config is intended, is when reboot ends with a stalled/hung
965 Currently, the only fixup is for the Geode machines using
966 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
968 Say Y if you want to enable the fixup. Currently, it's safe to
969 enable this option even if you don't need it.
973 tristate "/dev/cpu/microcode - microcode support"
976 If you say Y here, you will be able to update the microcode on
977 certain Intel and AMD processors. The Intel support is for the
978 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
979 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
980 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
981 You will obviously need the actual microcode binary data itself
982 which is not shipped with the Linux kernel.
984 This option selects the general module only, you need to select
985 at least one vendor specific module as well.
987 To compile this driver as a module, choose M here: the
988 module will be called microcode.
990 config MICROCODE_INTEL
991 bool "Intel microcode patch loading support"
996 This options enables microcode patch loading support for Intel
999 For latest news and information on obtaining all the required
1000 Intel ingredients for this driver, check:
1001 <http://www.urbanmyth.org/microcode/>.
1003 config MICROCODE_AMD
1004 bool "AMD microcode patch loading support"
1005 depends on MICROCODE
1008 If you select this option, microcode patch loading support for AMD
1009 processors will be enabled.
1011 config MICROCODE_OLD_INTERFACE
1013 depends on MICROCODE
1016 tristate "/dev/cpu/*/msr - Model-specific register support"
1018 This device gives privileged processes access to the x86
1019 Model-Specific Registers (MSRs). It is a character device with
1020 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1021 MSR accesses are directed to a specific CPU on multi-processor
1025 tristate "/dev/cpu/*/cpuid - CPU information support"
1027 This device gives processes access to the x86 CPUID instruction to
1028 be executed on a specific processor. It is a character device
1029 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1033 prompt "High Memory Support"
1034 default HIGHMEM4G if !X86_NUMAQ
1035 default HIGHMEM64G if X86_NUMAQ
1040 depends on !X86_NUMAQ
1042 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1043 However, the address space of 32-bit x86 processors is only 4
1044 Gigabytes large. That means that, if you have a large amount of
1045 physical memory, not all of it can be "permanently mapped" by the
1046 kernel. The physical memory that's not permanently mapped is called
1049 If you are compiling a kernel which will never run on a machine with
1050 more than 1 Gigabyte total physical RAM, answer "off" here (default
1051 choice and suitable for most users). This will result in a "3GB/1GB"
1052 split: 3GB are mapped so that each process sees a 3GB virtual memory
1053 space and the remaining part of the 4GB virtual memory space is used
1054 by the kernel to permanently map as much physical memory as
1057 If the machine has between 1 and 4 Gigabytes physical RAM, then
1060 If more than 4 Gigabytes is used then answer "64GB" here. This
1061 selection turns Intel PAE (Physical Address Extension) mode on.
1062 PAE implements 3-level paging on IA32 processors. PAE is fully
1063 supported by Linux, PAE mode is implemented on all recent Intel
1064 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1065 then the kernel will not boot on CPUs that don't support PAE!
1067 The actual amount of total physical memory will either be
1068 auto detected or can be forced by using a kernel command line option
1069 such as "mem=256M". (Try "man bootparam" or see the documentation of
1070 your boot loader (lilo or loadlin) about how to pass options to the
1071 kernel at boot time.)
1073 If unsure, say "off".
1077 depends on !X86_NUMAQ
1079 Select this if you have a 32-bit processor and between 1 and 4
1080 gigabytes of physical RAM.
1084 depends on !M386 && !M486
1087 Select this if you have a 32-bit processor and more than 4
1088 gigabytes of physical RAM.
1093 depends on EXPERIMENTAL
1094 prompt "Memory split" if EMBEDDED
1098 Select the desired split between kernel and user memory.
1100 If the address range available to the kernel is less than the
1101 physical memory installed, the remaining memory will be available
1102 as "high memory". Accessing high memory is a little more costly
1103 than low memory, as it needs to be mapped into the kernel first.
1104 Note that increasing the kernel address space limits the range
1105 available to user programs, making the address space there
1106 tighter. Selecting anything other than the default 3G/1G split
1107 will also likely make your kernel incompatible with binary-only
1110 If you are not absolutely sure what you are doing, leave this
1114 bool "3G/1G user/kernel split"
1115 config VMSPLIT_3G_OPT
1117 bool "3G/1G user/kernel split (for full 1G low memory)"
1119 bool "2G/2G user/kernel split"
1120 config VMSPLIT_2G_OPT
1122 bool "2G/2G user/kernel split (for full 2G low memory)"
1124 bool "1G/3G user/kernel split"
1129 default 0xB0000000 if VMSPLIT_3G_OPT
1130 default 0x80000000 if VMSPLIT_2G
1131 default 0x78000000 if VMSPLIT_2G_OPT
1132 default 0x40000000 if VMSPLIT_1G
1138 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1141 bool "PAE (Physical Address Extension) Support"
1142 depends on X86_32 && !HIGHMEM4G
1144 PAE is required for NX support, and furthermore enables
1145 larger swapspace support for non-overcommit purposes. It
1146 has the cost of more pagetable lookup overhead, and also
1147 consumes more pagetable space per process.
1149 config ARCH_PHYS_ADDR_T_64BIT
1150 def_bool X86_64 || X86_PAE
1152 config DIRECT_GBPAGES
1153 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1157 Allow the kernel linear mapping to use 1GB pages on CPUs that
1158 support it. This can improve the kernel's performance a tiny bit by
1159 reducing TLB pressure. If in doubt, say "Y".
1161 # Common NUMA Features
1163 bool "Numa Memory Allocation and Scheduler Support"
1165 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1166 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1168 Enable NUMA (Non Uniform Memory Access) support.
1170 The kernel will try to allocate memory used by a CPU on the
1171 local memory controller of the CPU and add some more
1172 NUMA awareness to the kernel.
1174 For 64-bit this is recommended if the system is Intel Core i7
1175 (or later), AMD Opteron, or EM64T NUMA.
1177 For 32-bit this is only needed on (rare) 32-bit-only platforms
1178 that support NUMA topologies, such as NUMAQ / Summit, or if you
1179 boot a 32-bit kernel on a 64-bit NUMA platform.
1181 Otherwise, you should say N.
1183 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1184 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1188 prompt "Old style AMD Opteron NUMA detection"
1189 depends on X86_64 && NUMA && PCI
1191 Enable K8 NUMA node topology detection. You should say Y here if
1192 you have a multi processor AMD K8 system. This uses an old
1193 method to read the NUMA configuration directly from the builtin
1194 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1195 instead, which also takes priority if both are compiled in.
1197 config X86_64_ACPI_NUMA
1199 prompt "ACPI NUMA detection"
1200 depends on X86_64 && NUMA && ACPI && PCI
1203 Enable ACPI SRAT based node topology detection.
1205 # Some NUMA nodes have memory ranges that span
1206 # other nodes. Even though a pfn is valid and
1207 # between a node's start and end pfns, it may not
1208 # reside on that node. See memmap_init_zone()
1210 config NODES_SPAN_OTHER_NODES
1212 depends on X86_64_ACPI_NUMA
1215 bool "NUMA emulation"
1216 depends on X86_64 && NUMA
1218 Enable NUMA emulation. A flat machine will be split
1219 into virtual nodes when booted with "numa=fake=N", where N is the
1220 number of nodes. This is only useful for debugging.
1223 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1225 default "10" if MAXSMP
1226 default "6" if X86_64
1227 default "4" if X86_NUMAQ
1229 depends on NEED_MULTIPLE_NODES
1231 Specify the maximum number of NUMA Nodes available on the target
1232 system. Increases memory reserved to accommodate various tables.
1234 config HAVE_ARCH_BOOTMEM
1236 depends on X86_32 && NUMA
1238 config ARCH_HAVE_MEMORY_PRESENT
1240 depends on X86_32 && DISCONTIGMEM
1242 config NEED_NODE_MEMMAP_SIZE
1244 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1246 config HAVE_ARCH_ALLOC_REMAP
1248 depends on X86_32 && NUMA
1250 config ARCH_FLATMEM_ENABLE
1252 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1254 config ARCH_DISCONTIGMEM_ENABLE
1256 depends on NUMA && X86_32
1258 config ARCH_DISCONTIGMEM_DEFAULT
1260 depends on NUMA && X86_32
1262 config ARCH_PROC_KCORE_TEXT
1264 depends on X86_64 && PROC_KCORE
1266 config ARCH_SPARSEMEM_DEFAULT
1270 config ARCH_SPARSEMEM_ENABLE
1272 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1273 select SPARSEMEM_STATIC if X86_32
1274 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1276 config ARCH_SELECT_MEMORY_MODEL
1278 depends on ARCH_SPARSEMEM_ENABLE
1280 config ARCH_MEMORY_PROBE
1282 depends on MEMORY_HOTPLUG
1284 config ILLEGAL_POINTER_VALUE
1287 default 0xdead000000000000 if X86_64
1292 bool "Allocate 3rd-level pagetables from highmem"
1293 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1295 The VM uses one page table entry for each page of physical memory.
1296 For systems with a lot of RAM, this can be wasteful of precious
1297 low memory. Setting this option will put user-space page table
1298 entries in high memory.
1300 config X86_CHECK_BIOS_CORRUPTION
1301 bool "Check for low memory corruption"
1303 Periodically check for memory corruption in low memory, which
1304 is suspected to be caused by BIOS. Even when enabled in the
1305 configuration, it is disabled at runtime. Enable it by
1306 setting "memory_corruption_check=1" on the kernel command
1307 line. By default it scans the low 64k of memory every 60
1308 seconds; see the memory_corruption_check_size and
1309 memory_corruption_check_period parameters in
1310 Documentation/kernel-parameters.txt to adjust this.
1312 When enabled with the default parameters, this option has
1313 almost no overhead, as it reserves a relatively small amount
1314 of memory and scans it infrequently. It both detects corruption
1315 and prevents it from affecting the running system.
1317 It is, however, intended as a diagnostic tool; if repeatable
1318 BIOS-originated corruption always affects the same memory,
1319 you can use memmap= to prevent the kernel from using that
1322 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1323 bool "Set the default setting of memory_corruption_check"
1324 depends on X86_CHECK_BIOS_CORRUPTION
1327 Set whether the default state of memory_corruption_check is
1330 config X86_RESERVE_LOW_64K
1331 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1334 Reserve the first 64K of physical RAM on BIOSes that are known
1335 to potentially corrupt that memory range. A numbers of BIOSes are
1336 known to utilize this area during suspend/resume, so it must not
1337 be used by the kernel.
1339 Set this to N if you are absolutely sure that you trust the BIOS
1340 to get all its memory reservations and usages right.
1342 If you have doubts about the BIOS (e.g. suspend/resume does not
1343 work or there's kernel crashes after certain hardware hotplug
1344 events) and it's not AMI or Phoenix, then you might want to enable
1345 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1346 corruption patterns.
1350 config MATH_EMULATION
1352 prompt "Math emulation" if X86_32
1354 Linux can emulate a math coprocessor (used for floating point
1355 operations) if you don't have one. 486DX and Pentium processors have
1356 a math coprocessor built in, 486SX and 386 do not, unless you added
1357 a 487DX or 387, respectively. (The messages during boot time can
1358 give you some hints here ["man dmesg"].) Everyone needs either a
1359 coprocessor or this emulation.
1361 If you don't have a math coprocessor, you need to say Y here; if you
1362 say Y here even though you have a coprocessor, the coprocessor will
1363 be used nevertheless. (This behavior can be changed with the kernel
1364 command line option "no387", which comes handy if your coprocessor
1365 is broken. Try "man bootparam" or see the documentation of your boot
1366 loader (lilo or loadlin) about how to pass options to the kernel at
1367 boot time.) This means that it is a good idea to say Y here if you
1368 intend to use this kernel on different machines.
1370 More information about the internals of the Linux math coprocessor
1371 emulation can be found in <file:arch/x86/math-emu/README>.
1373 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1374 kernel, it won't hurt.
1379 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1381 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1382 the Memory Type Range Registers (MTRRs) may be used to control
1383 processor access to memory ranges. This is most useful if you have
1384 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1385 allows bus write transfers to be combined into a larger transfer
1386 before bursting over the PCI/AGP bus. This can increase performance
1387 of image write operations 2.5 times or more. Saying Y here creates a
1388 /proc/mtrr file which may be used to manipulate your processor's
1389 MTRRs. Typically the X server should use this.
1391 This code has a reasonably generic interface so that similar
1392 control registers on other processors can be easily supported
1395 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1396 Registers (ARRs) which provide a similar functionality to MTRRs. For
1397 these, the ARRs are used to emulate the MTRRs.
1398 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1399 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1400 write-combining. All of these processors are supported by this code
1401 and it makes sense to say Y here if you have one of them.
1403 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1404 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1405 can lead to all sorts of problems, so it's good to say Y here.
1407 You can safely say Y even if your machine doesn't have MTRRs, you'll
1408 just add about 9 KB to your kernel.
1410 See <file:Documentation/x86/mtrr.txt> for more information.
1412 config MTRR_SANITIZER
1414 prompt "MTRR cleanup support"
1417 Convert MTRR layout from continuous to discrete, so X drivers can
1418 add writeback entries.
1420 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1421 The largest mtrr entry size for a continuous block can be set with
1426 config MTRR_SANITIZER_ENABLE_DEFAULT
1427 int "MTRR cleanup enable value (0-1)"
1430 depends on MTRR_SANITIZER
1432 Enable mtrr cleanup default value
1434 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1435 int "MTRR cleanup spare reg num (0-7)"
1438 depends on MTRR_SANITIZER
1440 mtrr cleanup spare entries default, it can be changed via
1441 mtrr_spare_reg_nr=N on the kernel command line.
1446 prompt "x86 PAT support" if EMBEDDED
1449 Use PAT attributes to setup page level cache control.
1451 PATs are the modern equivalents of MTRRs and are much more
1452 flexible than MTRRs.
1454 Say N here if you see bootup problems (boot crash, boot hang,
1455 spontaneous reboots) or a non-working video driver.
1459 config ARCH_USES_PG_UNCACHED
1464 bool "EFI runtime service support"
1467 This enables the kernel to use EFI runtime services that are
1468 available (such as the EFI variable services).
1470 This option is only useful on systems that have EFI firmware.
1471 In addition, you should use the latest ELILO loader available
1472 at <http://elilo.sourceforge.net> in order to take advantage
1473 of EFI runtime services. However, even with this option, the
1474 resultant kernel should continue to boot on existing non-EFI
1479 prompt "Enable seccomp to safely compute untrusted bytecode"
1481 This kernel feature is useful for number crunching applications
1482 that may need to compute untrusted bytecode during their
1483 execution. By using pipes or other transports made available to
1484 the process as file descriptors supporting the read/write
1485 syscalls, it's possible to isolate those applications in
1486 their own address space using seccomp. Once seccomp is
1487 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1488 and the task is only allowed to execute a few safe syscalls
1489 defined by each seccomp mode.
1491 If unsure, say Y. Only embedded should say N here.
1493 config CC_STACKPROTECTOR
1494 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1496 This option turns on the -fstack-protector GCC feature. This
1497 feature puts, at the beginning of functions, a canary value on
1498 the stack just before the return address, and validates
1499 the value just before actually returning. Stack based buffer
1500 overflows (that need to overwrite this return address) now also
1501 overwrite the canary, which gets detected and the attack is then
1502 neutralized via a kernel panic.
1504 This feature requires gcc version 4.2 or above, or a distribution
1505 gcc with the feature backported. Older versions are automatically
1506 detected and for those versions, this configuration option is
1507 ignored. (and a warning is printed during bootup)
1509 source kernel/Kconfig.hz
1512 bool "kexec system call"
1514 kexec is a system call that implements the ability to shutdown your
1515 current kernel, and to start another kernel. It is like a reboot
1516 but it is independent of the system firmware. And like a reboot
1517 you can start any kernel with it, not just Linux.
1519 The name comes from the similarity to the exec system call.
1521 It is an ongoing process to be certain the hardware in a machine
1522 is properly shutdown, so do not be surprised if this code does not
1523 initially work for you. It may help to enable device hotplugging
1524 support. As of this writing the exact hardware interface is
1525 strongly in flux, so no good recommendation can be made.
1528 bool "kernel crash dumps"
1529 depends on X86_64 || (X86_32 && HIGHMEM)
1531 Generate crash dump after being started by kexec.
1532 This should be normally only set in special crash dump kernels
1533 which are loaded in the main kernel with kexec-tools into
1534 a specially reserved region and then later executed after
1535 a crash by kdump/kexec. The crash dump kernel must be compiled
1536 to a memory address not used by the main kernel or BIOS using
1537 PHYSICAL_START, or it must be built as a relocatable image
1538 (CONFIG_RELOCATABLE=y).
1539 For more details see Documentation/kdump/kdump.txt
1542 bool "kexec jump (EXPERIMENTAL)"
1543 depends on EXPERIMENTAL
1544 depends on KEXEC && HIBERNATION
1546 Jump between original kernel and kexeced kernel and invoke
1547 code in physical address mode via KEXEC
1549 config PHYSICAL_START
1550 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1553 This gives the physical address where the kernel is loaded.
1555 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1556 bzImage will decompress itself to above physical address and
1557 run from there. Otherwise, bzImage will run from the address where
1558 it has been loaded by the boot loader and will ignore above physical
1561 In normal kdump cases one does not have to set/change this option
1562 as now bzImage can be compiled as a completely relocatable image
1563 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1564 address. This option is mainly useful for the folks who don't want
1565 to use a bzImage for capturing the crash dump and want to use a
1566 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1567 to be specifically compiled to run from a specific memory area
1568 (normally a reserved region) and this option comes handy.
1570 So if you are using bzImage for capturing the crash dump,
1571 leave the value here unchanged to 0x1000000 and set
1572 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1573 for capturing the crash dump change this value to start of
1574 the reserved region. In other words, it can be set based on
1575 the "X" value as specified in the "crashkernel=YM@XM"
1576 command line boot parameter passed to the panic-ed
1577 kernel. Please take a look at Documentation/kdump/kdump.txt
1578 for more details about crash dumps.
1580 Usage of bzImage for capturing the crash dump is recommended as
1581 one does not have to build two kernels. Same kernel can be used
1582 as production kernel and capture kernel. Above option should have
1583 gone away after relocatable bzImage support is introduced. But it
1584 is present because there are users out there who continue to use
1585 vmlinux for dump capture. This option should go away down the
1588 Don't change this unless you know what you are doing.
1591 bool "Build a relocatable kernel"
1594 This builds a kernel image that retains relocation information
1595 so it can be loaded someplace besides the default 1MB.
1596 The relocations tend to make the kernel binary about 10% larger,
1597 but are discarded at runtime.
1599 One use is for the kexec on panic case where the recovery kernel
1600 must live at a different physical address than the primary
1603 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1604 it has been loaded at and the compile time physical address
1605 (CONFIG_PHYSICAL_START) is ignored.
1607 # Relocation on x86-32 needs some additional build support
1608 config X86_NEED_RELOCS
1610 depends on X86_32 && RELOCATABLE
1612 config PHYSICAL_ALIGN
1614 prompt "Alignment value to which kernel should be aligned" if X86_32
1616 range 0x2000 0x1000000
1618 This value puts the alignment restrictions on physical address
1619 where kernel is loaded and run from. Kernel is compiled for an
1620 address which meets above alignment restriction.
1622 If bootloader loads the kernel at a non-aligned address and
1623 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1624 address aligned to above value and run from there.
1626 If bootloader loads the kernel at a non-aligned address and
1627 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1628 load address and decompress itself to the address it has been
1629 compiled for and run from there. The address for which kernel is
1630 compiled already meets above alignment restrictions. Hence the
1631 end result is that kernel runs from a physical address meeting
1632 above alignment restrictions.
1634 Don't change this unless you know what you are doing.
1637 bool "Support for hot-pluggable CPUs"
1638 depends on SMP && HOTPLUG
1640 Say Y here to allow turning CPUs off and on. CPUs can be
1641 controlled through /sys/devices/system/cpu.
1642 ( Note: power management support will enable this option
1643 automatically on SMP systems. )
1644 Say N if you want to disable CPU hotplug.
1648 prompt "Compat VDSO support"
1649 depends on X86_32 || IA32_EMULATION
1651 Map the 32-bit VDSO to the predictable old-style address too.
1653 Say N here if you are running a sufficiently recent glibc
1654 version (2.3.3 or later), to remove the high-mapped
1655 VDSO mapping and to exclusively use the randomized VDSO.
1660 bool "Built-in kernel command line"
1663 Allow for specifying boot arguments to the kernel at
1664 build time. On some systems (e.g. embedded ones), it is
1665 necessary or convenient to provide some or all of the
1666 kernel boot arguments with the kernel itself (that is,
1667 to not rely on the boot loader to provide them.)
1669 To compile command line arguments into the kernel,
1670 set this option to 'Y', then fill in the
1671 the boot arguments in CONFIG_CMDLINE.
1673 Systems with fully functional boot loaders (i.e. non-embedded)
1674 should leave this option set to 'N'.
1677 string "Built-in kernel command string"
1678 depends on CMDLINE_BOOL
1681 Enter arguments here that should be compiled into the kernel
1682 image and used at boot time. If the boot loader provides a
1683 command line at boot time, it is appended to this string to
1684 form the full kernel command line, when the system boots.
1686 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1687 change this behavior.
1689 In most cases, the command line (whether built-in or provided
1690 by the boot loader) should specify the device for the root
1693 config CMDLINE_OVERRIDE
1694 bool "Built-in command line overrides boot loader arguments"
1696 depends on CMDLINE_BOOL
1698 Set this option to 'Y' to have the kernel ignore the boot loader
1699 command line, and use ONLY the built-in command line.
1701 This is used to work around broken boot loaders. This should
1702 be set to 'N' under normal conditions.
1706 config ARCH_ENABLE_MEMORY_HOTPLUG
1708 depends on X86_64 || (X86_32 && HIGHMEM)
1710 config ARCH_ENABLE_MEMORY_HOTREMOVE
1712 depends on MEMORY_HOTPLUG
1714 config HAVE_ARCH_EARLY_PFN_TO_NID
1718 menu "Power management and ACPI options"
1720 config ARCH_HIBERNATION_HEADER
1722 depends on X86_64 && HIBERNATION
1724 source "kernel/power/Kconfig"
1726 source "drivers/acpi/Kconfig"
1728 source "drivers/sfi/Kconfig"
1733 depends on APM || APM_MODULE
1736 tristate "APM (Advanced Power Management) BIOS support"
1737 depends on X86_32 && PM_SLEEP
1739 APM is a BIOS specification for saving power using several different
1740 techniques. This is mostly useful for battery powered laptops with
1741 APM compliant BIOSes. If you say Y here, the system time will be
1742 reset after a RESUME operation, the /proc/apm device will provide
1743 battery status information, and user-space programs will receive
1744 notification of APM "events" (e.g. battery status change).
1746 If you select "Y" here, you can disable actual use of the APM
1747 BIOS by passing the "apm=off" option to the kernel at boot time.
1749 Note that the APM support is almost completely disabled for
1750 machines with more than one CPU.
1752 In order to use APM, you will need supporting software. For location
1753 and more information, read <file:Documentation/power/pm.txt> and the
1754 Battery Powered Linux mini-HOWTO, available from
1755 <http://www.tldp.org/docs.html#howto>.
1757 This driver does not spin down disk drives (see the hdparm(8)
1758 manpage ("man 8 hdparm") for that), and it doesn't turn off
1759 VESA-compliant "green" monitors.
1761 This driver does not support the TI 4000M TravelMate and the ACER
1762 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1763 desktop machines also don't have compliant BIOSes, and this driver
1764 may cause those machines to panic during the boot phase.
1766 Generally, if you don't have a battery in your machine, there isn't
1767 much point in using this driver and you should say N. If you get
1768 random kernel OOPSes or reboots that don't seem to be related to
1769 anything, try disabling/enabling this option (or disabling/enabling
1772 Some other things you should try when experiencing seemingly random,
1775 1) make sure that you have enough swap space and that it is
1777 2) pass the "no-hlt" option to the kernel
1778 3) switch on floating point emulation in the kernel and pass
1779 the "no387" option to the kernel
1780 4) pass the "floppy=nodma" option to the kernel
1781 5) pass the "mem=4M" option to the kernel (thereby disabling
1782 all but the first 4 MB of RAM)
1783 6) make sure that the CPU is not over clocked.
1784 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1785 8) disable the cache from your BIOS settings
1786 9) install a fan for the video card or exchange video RAM
1787 10) install a better fan for the CPU
1788 11) exchange RAM chips
1789 12) exchange the motherboard.
1791 To compile this driver as a module, choose M here: the
1792 module will be called apm.
1796 config APM_IGNORE_USER_SUSPEND
1797 bool "Ignore USER SUSPEND"
1799 This option will ignore USER SUSPEND requests. On machines with a
1800 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1801 series notebooks, it is necessary to say Y because of a BIOS bug.
1803 config APM_DO_ENABLE
1804 bool "Enable PM at boot time"
1806 Enable APM features at boot time. From page 36 of the APM BIOS
1807 specification: "When disabled, the APM BIOS does not automatically
1808 power manage devices, enter the Standby State, enter the Suspend
1809 State, or take power saving steps in response to CPU Idle calls."
1810 This driver will make CPU Idle calls when Linux is idle (unless this
1811 feature is turned off -- see "Do CPU IDLE calls", below). This
1812 should always save battery power, but more complicated APM features
1813 will be dependent on your BIOS implementation. You may need to turn
1814 this option off if your computer hangs at boot time when using APM
1815 support, or if it beeps continuously instead of suspending. Turn
1816 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1817 T400CDT. This is off by default since most machines do fine without
1821 bool "Make CPU Idle calls when idle"
1823 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1824 On some machines, this can activate improved power savings, such as
1825 a slowed CPU clock rate, when the machine is idle. These idle calls
1826 are made after the idle loop has run for some length of time (e.g.,
1827 333 mS). On some machines, this will cause a hang at boot time or
1828 whenever the CPU becomes idle. (On machines with more than one CPU,
1829 this option does nothing.)
1831 config APM_DISPLAY_BLANK
1832 bool "Enable console blanking using APM"
1834 Enable console blanking using the APM. Some laptops can use this to
1835 turn off the LCD backlight when the screen blanker of the Linux
1836 virtual console blanks the screen. Note that this is only used by
1837 the virtual console screen blanker, and won't turn off the backlight
1838 when using the X Window system. This also doesn't have anything to
1839 do with your VESA-compliant power-saving monitor. Further, this
1840 option doesn't work for all laptops -- it might not turn off your
1841 backlight at all, or it might print a lot of errors to the console,
1842 especially if you are using gpm.
1844 config APM_ALLOW_INTS
1845 bool "Allow interrupts during APM BIOS calls"
1847 Normally we disable external interrupts while we are making calls to
1848 the APM BIOS as a measure to lessen the effects of a badly behaving
1849 BIOS implementation. The BIOS should reenable interrupts if it
1850 needs to. Unfortunately, some BIOSes do not -- especially those in
1851 many of the newer IBM Thinkpads. If you experience hangs when you
1852 suspend, try setting this to Y. Otherwise, say N.
1856 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1858 source "drivers/cpuidle/Kconfig"
1860 source "drivers/idle/Kconfig"
1865 menu "Bus options (PCI etc.)"
1870 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1872 Find out whether you have a PCI motherboard. PCI is the name of a
1873 bus system, i.e. the way the CPU talks to the other stuff inside
1874 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1875 VESA. If you have PCI, say Y, otherwise N.
1878 prompt "PCI access mode"
1879 depends on X86_32 && PCI
1882 On PCI systems, the BIOS can be used to detect the PCI devices and
1883 determine their configuration. However, some old PCI motherboards
1884 have BIOS bugs and may crash if this is done. Also, some embedded
1885 PCI-based systems don't have any BIOS at all. Linux can also try to
1886 detect the PCI hardware directly without using the BIOS.
1888 With this option, you can specify how Linux should detect the
1889 PCI devices. If you choose "BIOS", the BIOS will be used,
1890 if you choose "Direct", the BIOS won't be used, and if you
1891 choose "MMConfig", then PCI Express MMCONFIG will be used.
1892 If you choose "Any", the kernel will try MMCONFIG, then the
1893 direct access method and falls back to the BIOS if that doesn't
1894 work. If unsure, go with the default, which is "Any".
1899 config PCI_GOMMCONFIG
1916 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1918 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1921 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1925 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1929 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1936 bool "Support mmconfig PCI config space access"
1937 depends on X86_64 && PCI && ACPI
1940 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1941 depends on PCI_MSI && ACPI && EXPERIMENTAL
1943 DMA remapping (DMAR) devices support enables independent address
1944 translations for Direct Memory Access (DMA) from devices.
1945 These DMA remapping devices are reported via ACPI tables
1946 and include PCI device scope covered by these DMA
1949 config DMAR_DEFAULT_ON
1951 prompt "Enable DMA Remapping Devices by default"
1954 Selecting this option will enable a DMAR device at boot time if
1955 one is found. If this option is not selected, DMAR support can
1956 be enabled by passing intel_iommu=on to the kernel. It is
1957 recommended you say N here while the DMAR code remains
1960 config DMAR_BROKEN_GFX_WA
1962 prompt "Workaround broken graphics drivers (going away soon)"
1963 depends on DMAR && BROKEN
1965 Current Graphics drivers tend to use physical address
1966 for DMA and avoid using DMA APIs. Setting this config
1967 option permits the IOMMU driver to set a unity map for
1968 all the OS-visible memory. Hence the driver can continue
1969 to use physical addresses for DMA, at least until this
1970 option is removed in the 2.6.32 kernel.
1972 config DMAR_FLOPPY_WA
1976 Floppy disk drivers are known to bypass DMA API calls
1977 thereby failing to work when IOMMU is enabled. This
1978 workaround will setup a 1:1 mapping for the first
1979 16MiB to make floppy (an ISA device) work.
1982 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1983 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1985 Supports Interrupt remapping for IO-APIC and MSI devices.
1986 To use x2apic mode in the CPU's which support x2APIC enhancements or
1987 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1989 source "drivers/pci/pcie/Kconfig"
1991 source "drivers/pci/Kconfig"
1993 # x86_64 have no ISA slots, but do have ISA-style DMA.
2002 Find out whether you have ISA slots on your motherboard. ISA is the
2003 name of a bus system, i.e. the way the CPU talks to the other stuff
2004 inside your box. Other bus systems are PCI, EISA, MicroChannel
2005 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2006 newer boards don't support it. If you have ISA, say Y, otherwise N.
2012 The Extended Industry Standard Architecture (EISA) bus was
2013 developed as an open alternative to the IBM MicroChannel bus.
2015 The EISA bus provided some of the features of the IBM MicroChannel
2016 bus while maintaining backward compatibility with cards made for
2017 the older ISA bus. The EISA bus saw limited use between 1988 and
2018 1995 when it was made obsolete by the PCI bus.
2020 Say Y here if you are building a kernel for an EISA-based machine.
2024 source "drivers/eisa/Kconfig"
2029 MicroChannel Architecture is found in some IBM PS/2 machines and
2030 laptops. It is a bus system similar to PCI or ISA. See
2031 <file:Documentation/mca.txt> (and especially the web page given
2032 there) before attempting to build an MCA bus kernel.
2034 source "drivers/mca/Kconfig"
2037 tristate "NatSemi SCx200 support"
2039 This provides basic support for National Semiconductor's
2040 (now AMD's) Geode processors. The driver probes for the
2041 PCI-IDs of several on-chip devices, so its a good dependency
2042 for other scx200_* drivers.
2044 If compiled as a module, the driver is named scx200.
2046 config SCx200HR_TIMER
2047 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2048 depends on SCx200 && GENERIC_TIME
2051 This driver provides a clocksource built upon the on-chip
2052 27MHz high-resolution timer. Its also a workaround for
2053 NSC Geode SC-1100's buggy TSC, which loses time when the
2054 processor goes idle (as is done by the scheduler). The
2055 other workaround is idle=poll boot option.
2058 bool "One Laptop Per Child support"
2062 Add support for detecting the unique features of the OLPC
2069 depends on CPU_SUP_AMD && PCI
2071 source "drivers/pcmcia/Kconfig"
2073 source "drivers/pci/hotplug/Kconfig"
2078 menu "Executable file formats / Emulations"
2080 source "fs/Kconfig.binfmt"
2082 config IA32_EMULATION
2083 bool "IA32 Emulation"
2085 select COMPAT_BINFMT_ELF
2087 Include code to run 32-bit programs under a 64-bit kernel. You should
2088 likely turn this on, unless you're 100% sure that you don't have any
2089 32-bit programs left.
2092 tristate "IA32 a.out support"
2093 depends on IA32_EMULATION
2095 Support old a.out binaries in the 32bit emulation.
2099 depends on IA32_EMULATION
2101 config COMPAT_FOR_U64_ALIGNMENT
2105 config SYSVIPC_COMPAT
2107 depends on COMPAT && SYSVIPC
2112 config HAVE_ATOMIC_IOMAP
2116 source "net/Kconfig"
2118 source "drivers/Kconfig"
2120 source "drivers/firmware/Kconfig"
2124 source "arch/x86/Kconfig.debug"
2126 source "security/Kconfig"
2128 source "crypto/Kconfig"
2130 source "arch/x86/kvm/Kconfig"
2132 source "lib/Kconfig"