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
56 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_ARCH_KMEMCHECK
60 select HAVE_USER_RETURN_NOTIFIER
62 config INSTRUCTION_DECODER
63 def_bool (KPROBES || PERF_EVENTS)
67 default "elf32-i386" if X86_32
68 default "elf64-x86-64" if X86_64
72 default "arch/x86/configs/i386_defconfig" if X86_32
73 default "arch/x86/configs/x86_64_defconfig" if X86_64
78 config GENERIC_CMOS_UPDATE
81 config CLOCKSOURCE_WATCHDOG
84 config GENERIC_CLOCKEVENTS
87 config GENERIC_CLOCKEVENTS_BROADCAST
89 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
91 config LOCKDEP_SUPPORT
94 config STACKTRACE_SUPPORT
97 config HAVE_LATENCYTOP_SUPPORT
109 config NEED_DMA_MAP_STATE
110 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
112 config GENERIC_ISA_DMA
121 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
123 config GENERIC_BUG_RELATIVE_POINTERS
126 config GENERIC_HWEIGHT
132 config ARCH_MAY_HAVE_PC_FDC
135 config RWSEM_GENERIC_SPINLOCK
138 config RWSEM_XCHGADD_ALGORITHM
141 config ARCH_HAS_CPU_IDLE_WAIT
144 config GENERIC_CALIBRATE_DELAY
147 config GENERIC_TIME_VSYSCALL
151 config ARCH_HAS_CPU_RELAX
154 config ARCH_HAS_DEFAULT_IDLE
157 config ARCH_HAS_CACHE_LINE_SIZE
160 config HAVE_SETUP_PER_CPU_AREA
163 config NEED_PER_CPU_EMBED_FIRST_CHUNK
166 config NEED_PER_CPU_PAGE_FIRST_CHUNK
169 config HAVE_CPUMASK_OF_CPU_MAP
172 config ARCH_HIBERNATION_POSSIBLE
175 config ARCH_SUSPEND_POSSIBLE
182 config ARCH_POPULATES_NODE_MAP
189 config ARCH_SUPPORTS_OPTIMIZED_INLINING
192 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
195 config HAVE_EARLY_RES
198 config HAVE_INTEL_TXT
200 depends on EXPERIMENTAL && DMAR && ACPI
202 # Use the generic interrupt handling code in kernel/irq/:
203 config GENERIC_HARDIRQS
207 config GENERIC_HARDIRQS_NO__DO_IRQ
210 config GENERIC_IRQ_PROBE
214 config GENERIC_PENDING_IRQ
216 depends on GENERIC_HARDIRQS && SMP
219 config USE_GENERIC_SMP_HELPERS
225 depends on X86_32 && SMP
229 depends on X86_64 && SMP
236 config X86_TRAMPOLINE
238 depends on SMP || (64BIT && ACPI_SLEEP)
241 config X86_32_LAZY_GS
243 depends on X86_32 && !CC_STACKPROTECTOR
247 source "init/Kconfig"
248 source "kernel/Kconfig.freezer"
250 menu "Processor type and features"
252 source "kernel/time/Kconfig"
255 bool "Symmetric multi-processing support"
257 This enables support for systems with more than one CPU. If you have
258 a system with only one CPU, like most personal computers, say N. If
259 you have a system with more than one CPU, say Y.
261 If you say N here, the kernel will run on single and multiprocessor
262 machines, but will use only one CPU of a multiprocessor machine. If
263 you say Y here, the kernel will run on many, but not all,
264 singleprocessor machines. On a singleprocessor machine, the kernel
265 will run faster if you say N here.
267 Note that if you say Y here and choose architecture "586" or
268 "Pentium" under "Processor family", the kernel will not work on 486
269 architectures. Similarly, multiprocessor kernels for the "PPro"
270 architecture may not work on all Pentium based boards.
272 People using multiprocessor machines who say Y here should also say
273 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
274 Management" code will be disabled if you say Y here.
276 See also <file:Documentation/i386/IO-APIC.txt>,
277 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
278 <http://www.tldp.org/docs.html#howto>.
280 If you don't know what to do here, say N.
283 bool "Support x2apic"
284 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
286 This enables x2apic support on CPUs that have this feature.
288 This allows 32-bit apic IDs (so it can support very large systems),
289 and accesses the local apic via MSRs not via mmio.
291 If you don't know what to do here, say N.
294 bool "Support sparse irq numbering"
295 depends on PCI_MSI || HT_IRQ
297 This enables support for sparse irqs. This is useful for distro
298 kernels that want to define a high CONFIG_NR_CPUS value but still
299 want to have low kernel memory footprint on smaller machines.
301 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
302 out the irq_desc[] array in a more NUMA-friendly way. )
304 If you don't know what to do here, say N.
308 depends on SPARSE_IRQ && NUMA
311 bool "Enable MPS table" if ACPI
313 depends on X86_LOCAL_APIC
315 For old smp systems that do not have proper acpi support. Newer systems
316 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
319 bool "Support for big SMP systems with more than 8 CPUs"
320 depends on X86_32 && SMP
322 This option is needed for the systems that have more than 8 CPUs
325 config X86_EXTENDED_PLATFORM
326 bool "Support for extended (non-PC) x86 platforms"
329 If you disable this option then the kernel will only support
330 standard PC platforms. (which covers the vast majority of
333 If you enable this option then you'll be able to select support
334 for the following (non-PC) 32 bit x86 platforms:
338 SGI 320/540 (Visual Workstation)
339 Summit/EXA (IBM x440)
340 Unisys ES7000 IA32 series
341 Moorestown MID devices
343 If you have one of these systems, or if you want to build a
344 generic distribution kernel, say Y here - otherwise say N.
348 config X86_EXTENDED_PLATFORM
349 bool "Support for extended (non-PC) x86 platforms"
352 If you disable this option then the kernel will only support
353 standard PC platforms. (which covers the vast majority of
356 If you enable this option then you'll be able to select support
357 for the following (non-PC) 64 bit x86 platforms:
361 If you have one of these systems, or if you want to build a
362 generic distribution kernel, say Y here - otherwise say N.
364 # This is an alphabetically sorted list of 64 bit extended platforms
365 # Please maintain the alphabetic order if and when there are additions
370 depends on X86_64 && PCI
371 depends on X86_EXTENDED_PLATFORM
373 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
374 supposed to run on these EM64T-based machines. Only choose this option
375 if you have one of these machines.
378 bool "SGI Ultraviolet"
380 depends on X86_EXTENDED_PLATFORM
382 depends on X86_X2APIC
384 This option is needed in order to support SGI Ultraviolet systems.
385 If you don't have one of these, you should say N here.
387 # Following is an alphabetically sorted list of 32 bit extended platforms
388 # Please maintain the alphabetic order if and when there are additions
393 depends on X86_EXTENDED_PLATFORM
395 Select this for an AMD Elan processor.
397 Do not use this option for K6/Athlon/Opteron processors!
399 If unsure, choose "PC-compatible" instead.
402 bool "Moorestown MID platform"
406 depends on X86_EXTENDED_PLATFORM
407 depends on X86_IO_APIC
410 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
411 Internet Device(MID) platform. Moorestown consists of two chips:
412 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
413 Unlike standard x86 PCs, Moorestown does not have many legacy devices
414 nor standard legacy replacement devices/features. e.g. Moorestown does
415 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
418 bool "RDC R-321x SoC"
420 depends on X86_EXTENDED_PLATFORM
422 select X86_REBOOTFIXUPS
424 This option is needed for RDC R-321x system-on-chip, also known
426 If you don't have one of these chips, you should say N here.
428 config X86_32_NON_STANDARD
429 bool "Support non-standard 32-bit SMP architectures"
430 depends on X86_32 && SMP
431 depends on X86_EXTENDED_PLATFORM
433 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
434 subarchitectures. It is intended for a generic binary kernel.
435 if you select them all, kernel will probe it one by one. and will
438 # Alphabetically sorted list of Non standard 32 bit platforms
441 bool "NUMAQ (IBM/Sequent)"
442 depends on X86_32_NON_STANDARD
447 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
448 NUMA multiquad box. This changes the way that processors are
449 bootstrapped, and uses Clustered Logical APIC addressing mode instead
450 of Flat Logical. You will need a new lynxer.elf file to flash your
451 firmware with - send email to <Martin.Bligh@us.ibm.com>.
453 config X86_SUPPORTS_MEMORY_FAILURE
455 # MCE code calls memory_failure():
457 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
458 depends on !X86_NUMAQ
459 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
460 depends on X86_64 || !SPARSEMEM
461 select ARCH_SUPPORTS_MEMORY_FAILURE
465 bool "SGI 320/540 (Visual Workstation)"
466 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
467 depends on X86_32_NON_STANDARD
469 The SGI Visual Workstation series is an IA32-based workstation
470 based on SGI systems chips with some legacy PC hardware attached.
472 Say Y here to create a kernel to run on the SGI 320 or 540.
474 A kernel compiled for the Visual Workstation will run on general
475 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
478 bool "Summit/EXA (IBM x440)"
479 depends on X86_32_NON_STANDARD
481 This option is needed for IBM systems that use the Summit/EXA chipset.
482 In particular, it is needed for the x440.
485 bool "Unisys ES7000 IA32 series"
486 depends on X86_32_NON_STANDARD && X86_BIGSMP
488 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
489 supposed to run on an IA32-based Unisys ES7000 system.
491 config SCHED_OMIT_FRAME_POINTER
493 prompt "Single-depth WCHAN output"
496 Calculate simpler /proc/<PID>/wchan values. If this option
497 is disabled then wchan values will recurse back to the
498 caller function. This provides more accurate wchan values,
499 at the expense of slightly more scheduling overhead.
501 If in doubt, say "Y".
503 menuconfig PARAVIRT_GUEST
504 bool "Paravirtualized guest support"
506 Say Y here to get to see options related to running Linux under
507 various hypervisors. This option alone does not add any kernel code.
509 If you say N, all options in this submenu will be skipped and disabled.
513 source "arch/x86/xen/Kconfig"
516 bool "VMI Guest support (DEPRECATED)"
520 VMI provides a paravirtualized interface to the VMware ESX server
521 (it could be used by other hypervisors in theory too, but is not
522 at the moment), by linking the kernel to a GPL-ed ROM module
523 provided by the hypervisor.
525 As of September 2009, VMware has started a phased retirement
526 of this feature from VMware's products. Please see
527 feature-removal-schedule.txt for details. If you are
528 planning to enable this option, please note that you cannot
529 live migrate a VMI enabled VM to a future VMware product,
530 which doesn't support VMI. So if you expect your kernel to
531 seamlessly migrate to newer VMware products, keep this
535 bool "KVM paravirtualized clock"
537 select PARAVIRT_CLOCK
539 Turning on this option will allow you to run a paravirtualized clock
540 when running over the KVM hypervisor. Instead of relying on a PIT
541 (or probably other) emulation by the underlying device model, the host
542 provides the guest with timing infrastructure such as time of day, and
546 bool "KVM Guest support"
549 This option enables various optimizations for running under the KVM
552 source "arch/x86/lguest/Kconfig"
555 bool "Enable paravirtualization code"
557 This changes the kernel so it can modify itself when it is run
558 under a hypervisor, potentially improving performance significantly
559 over full virtualization. However, when run without a hypervisor
560 the kernel is theoretically slower and slightly larger.
562 config PARAVIRT_SPINLOCKS
563 bool "Paravirtualization layer for spinlocks"
564 depends on PARAVIRT && SMP && EXPERIMENTAL
566 Paravirtualized spinlocks allow a pvops backend to replace the
567 spinlock implementation with something virtualization-friendly
568 (for example, block the virtual CPU rather than spinning).
570 Unfortunately the downside is an up to 5% performance hit on
571 native kernels, with various workloads.
573 If you are unsure how to answer this question, answer N.
575 config PARAVIRT_CLOCK
581 config PARAVIRT_DEBUG
582 bool "paravirt-ops debugging"
583 depends on PARAVIRT && DEBUG_KERNEL
585 Enable to debug paravirt_ops internals. Specifically, BUG if
586 a paravirt_op is missing when it is called.
590 bool "Disable Bootmem code"
592 Use early_res directly instead of bootmem before slab is ready.
593 - allocator (buddy) [generic]
594 - early allocator (bootmem) [generic]
595 - very early allocator (reserve_early*()) [x86]
596 - very very early allocator (early brk model) [x86]
597 So reduce one layer between early allocator to final allocator
603 This option adds a kernel parameter 'memtest', which allows memtest
605 memtest=0, mean disabled; -- default
606 memtest=1, mean do 1 test pattern;
608 memtest=4, mean do 4 test patterns.
609 If you are unsure how to answer this question, answer N.
611 config X86_SUMMIT_NUMA
613 depends on X86_32 && NUMA && X86_32_NON_STANDARD
615 config X86_CYCLONE_TIMER
617 depends on X86_32_NON_STANDARD
619 source "arch/x86/Kconfig.cpu"
623 prompt "HPET Timer Support" if X86_32
625 Use the IA-PC HPET (High Precision Event Timer) to manage
626 time in preference to the PIT and RTC, if a HPET is
628 HPET is the next generation timer replacing legacy 8254s.
629 The HPET provides a stable time base on SMP
630 systems, unlike the TSC, but it is more expensive to access,
631 as it is off-chip. You can find the HPET spec at
632 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
634 You can safely choose Y here. However, HPET will only be
635 activated if the platform and the BIOS support this feature.
636 Otherwise the 8254 will be used for timing services.
638 Choose N to continue using the legacy 8254 timer.
640 config HPET_EMULATE_RTC
642 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
646 prompt "Langwell APB Timer Support" if X86_MRST
648 APB timer is the replacement for 8254, HPET on X86 MID platforms.
649 The APBT provides a stable time base on SMP
650 systems, unlike the TSC, but it is more expensive to access,
651 as it is off-chip. APB timers are always running regardless of CPU
652 C states, they are used as per CPU clockevent device when possible.
654 # Mark as embedded because too many people got it wrong.
655 # The code disables itself when not needed.
658 bool "Enable DMI scanning" if EMBEDDED
660 Enabled scanning of DMI to identify machine quirks. Say Y
661 here unless you have verified that your setup is not
662 affected by entries in the DMI blacklist. Required by PNP
666 bool "GART IOMMU support" if EMBEDDED
669 depends on X86_64 && PCI && K8_NB
671 Support for full DMA access of devices with 32bit memory access only
672 on systems with more than 3GB. This is usually needed for USB,
673 sound, many IDE/SATA chipsets and some other devices.
674 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
675 based hardware IOMMU and a software bounce buffer based IOMMU used
676 on Intel systems and as fallback.
677 The code is only active when needed (enough memory and limited
678 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
682 bool "IBM Calgary IOMMU support"
684 depends on X86_64 && PCI && EXPERIMENTAL
686 Support for hardware IOMMUs in IBM's xSeries x366 and x460
687 systems. Needed to run systems with more than 3GB of memory
688 properly with 32-bit PCI devices that do not support DAC
689 (Double Address Cycle). Calgary also supports bus level
690 isolation, where all DMAs pass through the IOMMU. This
691 prevents them from going anywhere except their intended
692 destination. This catches hard-to-find kernel bugs and
693 mis-behaving drivers and devices that do not use the DMA-API
694 properly to set up their DMA buffers. The IOMMU can be
695 turned off at boot time with the iommu=off parameter.
696 Normally the kernel will make the right choice by itself.
699 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
701 prompt "Should Calgary be enabled by default?"
702 depends on CALGARY_IOMMU
704 Should Calgary be enabled by default? if you choose 'y', Calgary
705 will be used (if it exists). If you choose 'n', Calgary will not be
706 used even if it exists. If you choose 'n' and would like to use
707 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
711 bool "AMD IOMMU support"
714 depends on X86_64 && PCI && ACPI
716 With this option you can enable support for AMD IOMMU hardware in
717 your system. An IOMMU is a hardware component which provides
718 remapping of DMA memory accesses from devices. With an AMD IOMMU you
719 can isolate the the DMA memory of different devices and protect the
720 system from misbehaving device drivers or hardware.
722 You can find out if your system has an AMD IOMMU if you look into
723 your BIOS for an option to enable it or if you have an IVRS ACPI
726 config AMD_IOMMU_STATS
727 bool "Export AMD IOMMU statistics to debugfs"
731 This option enables code in the AMD IOMMU driver to collect various
732 statistics about whats happening in the driver and exports that
733 information to userspace via debugfs.
736 # need this always selected by IOMMU for the VIA workaround
740 Support for software bounce buffers used on x86-64 systems
741 which don't have a hardware IOMMU (e.g. the current generation
742 of Intel's x86-64 CPUs). Using this PCI devices which can only
743 access 32-bits of memory can be used on systems with more than
744 3 GB of memory. If unsure, say Y.
747 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
750 def_bool (AMD_IOMMU || DMAR)
753 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
754 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
755 select CPUMASK_OFFSTACK
758 Configure maximum number of CPUS and NUMA Nodes for this architecture.
762 int "Maximum number of CPUs" if SMP && !MAXSMP
763 range 2 8 if SMP && X86_32 && !X86_BIGSMP
764 range 2 512 if SMP && !MAXSMP
766 default "4096" if MAXSMP
767 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
770 This allows you to specify the maximum number of CPUs which this
771 kernel will support. The maximum supported value is 512 and the
772 minimum value which makes sense is 2.
774 This is purely to save memory - each supported CPU adds
775 approximately eight kilobytes to the kernel image.
778 bool "SMT (Hyperthreading) scheduler support"
781 SMT scheduler support improves the CPU scheduler's decision making
782 when dealing with Intel Pentium 4 chips with HyperThreading at a
783 cost of slightly increased overhead in some places. If unsure say
788 prompt "Multi-core scheduler support"
791 Multi-core scheduler support improves the CPU scheduler's decision
792 making when dealing with multi-core CPU chips at a cost of slightly
793 increased overhead in some places. If unsure say N here.
795 source "kernel/Kconfig.preempt"
798 bool "Local APIC support on uniprocessors"
799 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
801 A local APIC (Advanced Programmable Interrupt Controller) is an
802 integrated interrupt controller in the CPU. If you have a single-CPU
803 system which has a processor with a local APIC, you can say Y here to
804 enable and use it. If you say Y here even though your machine doesn't
805 have a local APIC, then the kernel will still run with no slowdown at
806 all. The local APIC supports CPU-generated self-interrupts (timer,
807 performance counters), and the NMI watchdog which detects hard
811 bool "IO-APIC support on uniprocessors"
812 depends on X86_UP_APIC
814 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
815 SMP-capable replacement for PC-style interrupt controllers. Most
816 SMP systems and many recent uniprocessor systems have one.
818 If you have a single-CPU system with an IO-APIC, you can say Y here
819 to use it. If you say Y here even though your machine doesn't have
820 an IO-APIC, then the kernel will still run with no slowdown at all.
822 config X86_LOCAL_APIC
824 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
828 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
830 config X86_VISWS_APIC
832 depends on X86_32 && X86_VISWS
834 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
835 bool "Reroute for broken boot IRQs"
837 depends on X86_IO_APIC
839 This option enables a workaround that fixes a source of
840 spurious interrupts. This is recommended when threaded
841 interrupt handling is used on systems where the generation of
842 superfluous "boot interrupts" cannot be disabled.
844 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
845 entry in the chipset's IO-APIC is masked (as, e.g. the RT
846 kernel does during interrupt handling). On chipsets where this
847 boot IRQ generation cannot be disabled, this workaround keeps
848 the original IRQ line masked so that only the equivalent "boot
849 IRQ" is delivered to the CPUs. The workaround also tells the
850 kernel to set up the IRQ handler on the boot IRQ line. In this
851 way only one interrupt is delivered to the kernel. Otherwise
852 the spurious second interrupt may cause the kernel to bring
853 down (vital) interrupt lines.
855 Only affects "broken" chipsets. Interrupt sharing may be
856 increased on these systems.
859 bool "Machine Check / overheating reporting"
861 Machine Check support allows the processor to notify the
862 kernel if it detects a problem (e.g. overheating, data corruption).
863 The action the kernel takes depends on the severity of the problem,
864 ranging from warning messages to halting the machine.
868 prompt "Intel MCE features"
869 depends on X86_MCE && X86_LOCAL_APIC
871 Additional support for intel specific MCE features such as
876 prompt "AMD MCE features"
877 depends on X86_MCE && X86_LOCAL_APIC
879 Additional support for AMD specific MCE features such as
880 the DRAM Error Threshold.
882 config X86_ANCIENT_MCE
884 depends on X86_32 && X86_MCE
885 prompt "Support for old Pentium 5 / WinChip machine checks"
887 Include support for machine check handling on old Pentium 5 or WinChip
888 systems. These typically need to be enabled explicitely on the command
891 config X86_MCE_THRESHOLD
892 depends on X86_MCE_AMD || X86_MCE_INTEL
896 config X86_MCE_INJECT
898 tristate "Machine check injector support"
900 Provide support for injecting machine checks for testing purposes.
901 If you don't know what a machine check is and you don't do kernel
902 QA it is safe to say n.
904 config X86_THERMAL_VECTOR
906 depends on X86_MCE_INTEL
909 bool "Enable VM86 support" if EMBEDDED
913 This option is required by programs like DOSEMU to run 16-bit legacy
914 code on X86 processors. It also may be needed by software like
915 XFree86 to initialize some video cards via BIOS. Disabling this
916 option saves about 6k.
919 tristate "Toshiba Laptop support"
922 This adds a driver to safely access the System Management Mode of
923 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
924 not work on models with a Phoenix BIOS. The System Management Mode
925 is used to set the BIOS and power saving options on Toshiba portables.
927 For information on utilities to make use of this driver see the
928 Toshiba Linux utilities web site at:
929 <http://www.buzzard.org.uk/toshiba/>.
931 Say Y if you intend to run this kernel on a Toshiba portable.
935 tristate "Dell laptop support"
937 This adds a driver to safely access the System Management Mode
938 of the CPU on the Dell Inspiron 8000. The System Management Mode
939 is used to read cpu temperature and cooling fan status and to
940 control the fans on the I8K portables.
942 This driver has been tested only on the Inspiron 8000 but it may
943 also work with other Dell laptops. You can force loading on other
944 models by passing the parameter `force=1' to the module. Use at
947 For information on utilities to make use of this driver see the
948 I8K Linux utilities web site at:
949 <http://people.debian.org/~dz/i8k/>
951 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
954 config X86_REBOOTFIXUPS
955 bool "Enable X86 board specific fixups for reboot"
958 This enables chipset and/or board specific fixups to be done
959 in order to get reboot to work correctly. This is only needed on
960 some combinations of hardware and BIOS. The symptom, for which
961 this config is intended, is when reboot ends with a stalled/hung
964 Currently, the only fixup is for the Geode machines using
965 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
967 Say Y if you want to enable the fixup. Currently, it's safe to
968 enable this option even if you don't need it.
972 tristate "/dev/cpu/microcode - microcode support"
975 If you say Y here, you will be able to update the microcode on
976 certain Intel and AMD processors. The Intel support is for the
977 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
978 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
979 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
980 You will obviously need the actual microcode binary data itself
981 which is not shipped with the Linux kernel.
983 This option selects the general module only, you need to select
984 at least one vendor specific module as well.
986 To compile this driver as a module, choose M here: the
987 module will be called microcode.
989 config MICROCODE_INTEL
990 bool "Intel microcode patch loading support"
995 This options enables microcode patch loading support for Intel
998 For latest news and information on obtaining all the required
999 Intel ingredients for this driver, check:
1000 <http://www.urbanmyth.org/microcode/>.
1002 config MICROCODE_AMD
1003 bool "AMD microcode patch loading support"
1004 depends on MICROCODE
1007 If you select this option, microcode patch loading support for AMD
1008 processors will be enabled.
1010 config MICROCODE_OLD_INTERFACE
1012 depends on MICROCODE
1015 tristate "/dev/cpu/*/msr - Model-specific register support"
1017 This device gives privileged processes access to the x86
1018 Model-Specific Registers (MSRs). It is a character device with
1019 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1020 MSR accesses are directed to a specific CPU on multi-processor
1024 tristate "/dev/cpu/*/cpuid - CPU information support"
1026 This device gives processes access to the x86 CPUID instruction to
1027 be executed on a specific processor. It is a character device
1028 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1032 prompt "High Memory Support"
1033 default HIGHMEM4G if !X86_NUMAQ
1034 default HIGHMEM64G if X86_NUMAQ
1039 depends on !X86_NUMAQ
1041 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1042 However, the address space of 32-bit x86 processors is only 4
1043 Gigabytes large. That means that, if you have a large amount of
1044 physical memory, not all of it can be "permanently mapped" by the
1045 kernel. The physical memory that's not permanently mapped is called
1048 If you are compiling a kernel which will never run on a machine with
1049 more than 1 Gigabyte total physical RAM, answer "off" here (default
1050 choice and suitable for most users). This will result in a "3GB/1GB"
1051 split: 3GB are mapped so that each process sees a 3GB virtual memory
1052 space and the remaining part of the 4GB virtual memory space is used
1053 by the kernel to permanently map as much physical memory as
1056 If the machine has between 1 and 4 Gigabytes physical RAM, then
1059 If more than 4 Gigabytes is used then answer "64GB" here. This
1060 selection turns Intel PAE (Physical Address Extension) mode on.
1061 PAE implements 3-level paging on IA32 processors. PAE is fully
1062 supported by Linux, PAE mode is implemented on all recent Intel
1063 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1064 then the kernel will not boot on CPUs that don't support PAE!
1066 The actual amount of total physical memory will either be
1067 auto detected or can be forced by using a kernel command line option
1068 such as "mem=256M". (Try "man bootparam" or see the documentation of
1069 your boot loader (lilo or loadlin) about how to pass options to the
1070 kernel at boot time.)
1072 If unsure, say "off".
1076 depends on !X86_NUMAQ
1078 Select this if you have a 32-bit processor and between 1 and 4
1079 gigabytes of physical RAM.
1083 depends on !M386 && !M486
1086 Select this if you have a 32-bit processor and more than 4
1087 gigabytes of physical RAM.
1092 depends on EXPERIMENTAL
1093 prompt "Memory split" if EMBEDDED
1097 Select the desired split between kernel and user memory.
1099 If the address range available to the kernel is less than the
1100 physical memory installed, the remaining memory will be available
1101 as "high memory". Accessing high memory is a little more costly
1102 than low memory, as it needs to be mapped into the kernel first.
1103 Note that increasing the kernel address space limits the range
1104 available to user programs, making the address space there
1105 tighter. Selecting anything other than the default 3G/1G split
1106 will also likely make your kernel incompatible with binary-only
1109 If you are not absolutely sure what you are doing, leave this
1113 bool "3G/1G user/kernel split"
1114 config VMSPLIT_3G_OPT
1116 bool "3G/1G user/kernel split (for full 1G low memory)"
1118 bool "2G/2G user/kernel split"
1119 config VMSPLIT_2G_OPT
1121 bool "2G/2G user/kernel split (for full 2G low memory)"
1123 bool "1G/3G user/kernel split"
1128 default 0xB0000000 if VMSPLIT_3G_OPT
1129 default 0x80000000 if VMSPLIT_2G
1130 default 0x78000000 if VMSPLIT_2G_OPT
1131 default 0x40000000 if VMSPLIT_1G
1137 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1140 bool "PAE (Physical Address Extension) Support"
1141 depends on X86_32 && !HIGHMEM4G
1143 PAE is required for NX support, and furthermore enables
1144 larger swapspace support for non-overcommit purposes. It
1145 has the cost of more pagetable lookup overhead, and also
1146 consumes more pagetable space per process.
1148 config ARCH_PHYS_ADDR_T_64BIT
1149 def_bool X86_64 || X86_PAE
1151 config DIRECT_GBPAGES
1152 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1156 Allow the kernel linear mapping to use 1GB pages on CPUs that
1157 support it. This can improve the kernel's performance a tiny bit by
1158 reducing TLB pressure. If in doubt, say "Y".
1160 # Common NUMA Features
1162 bool "Numa Memory Allocation and Scheduler Support"
1164 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1165 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1167 Enable NUMA (Non Uniform Memory Access) support.
1169 The kernel will try to allocate memory used by a CPU on the
1170 local memory controller of the CPU and add some more
1171 NUMA awareness to the kernel.
1173 For 64-bit this is recommended if the system is Intel Core i7
1174 (or later), AMD Opteron, or EM64T NUMA.
1176 For 32-bit this is only needed on (rare) 32-bit-only platforms
1177 that support NUMA topologies, such as NUMAQ / Summit, or if you
1178 boot a 32-bit kernel on a 64-bit NUMA platform.
1180 Otherwise, you should say N.
1182 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1183 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1187 prompt "Old style AMD Opteron NUMA detection"
1188 depends on X86_64 && NUMA && PCI
1190 Enable K8 NUMA node topology detection. You should say Y here if
1191 you have a multi processor AMD K8 system. This uses an old
1192 method to read the NUMA configuration directly from the builtin
1193 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1194 instead, which also takes priority if both are compiled in.
1196 config X86_64_ACPI_NUMA
1198 prompt "ACPI NUMA detection"
1199 depends on X86_64 && NUMA && ACPI && PCI
1202 Enable ACPI SRAT based node topology detection.
1204 # Some NUMA nodes have memory ranges that span
1205 # other nodes. Even though a pfn is valid and
1206 # between a node's start and end pfns, it may not
1207 # reside on that node. See memmap_init_zone()
1209 config NODES_SPAN_OTHER_NODES
1211 depends on X86_64_ACPI_NUMA
1214 bool "NUMA emulation"
1215 depends on X86_64 && NUMA
1217 Enable NUMA emulation. A flat machine will be split
1218 into virtual nodes when booted with "numa=fake=N", where N is the
1219 number of nodes. This is only useful for debugging.
1222 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1224 default "10" if MAXSMP
1225 default "6" if X86_64
1226 default "4" if X86_NUMAQ
1228 depends on NEED_MULTIPLE_NODES
1230 Specify the maximum number of NUMA Nodes available on the target
1231 system. Increases memory reserved to accommodate various tables.
1233 config HAVE_ARCH_BOOTMEM
1235 depends on X86_32 && NUMA
1237 config ARCH_HAVE_MEMORY_PRESENT
1239 depends on X86_32 && DISCONTIGMEM
1241 config NEED_NODE_MEMMAP_SIZE
1243 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1245 config HAVE_ARCH_ALLOC_REMAP
1247 depends on X86_32 && NUMA
1249 config ARCH_FLATMEM_ENABLE
1251 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1253 config ARCH_DISCONTIGMEM_ENABLE
1255 depends on NUMA && X86_32
1257 config ARCH_DISCONTIGMEM_DEFAULT
1259 depends on NUMA && X86_32
1261 config ARCH_PROC_KCORE_TEXT
1263 depends on X86_64 && PROC_KCORE
1265 config ARCH_SPARSEMEM_DEFAULT
1269 config ARCH_SPARSEMEM_ENABLE
1271 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1272 select SPARSEMEM_STATIC if X86_32
1273 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1275 config ARCH_SELECT_MEMORY_MODEL
1277 depends on ARCH_SPARSEMEM_ENABLE
1279 config ARCH_MEMORY_PROBE
1281 depends on MEMORY_HOTPLUG
1283 config ILLEGAL_POINTER_VALUE
1286 default 0xdead000000000000 if X86_64
1291 bool "Allocate 3rd-level pagetables from highmem"
1292 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1294 The VM uses one page table entry for each page of physical memory.
1295 For systems with a lot of RAM, this can be wasteful of precious
1296 low memory. Setting this option will put user-space page table
1297 entries in high memory.
1299 config X86_CHECK_BIOS_CORRUPTION
1300 bool "Check for low memory corruption"
1302 Periodically check for memory corruption in low memory, which
1303 is suspected to be caused by BIOS. Even when enabled in the
1304 configuration, it is disabled at runtime. Enable it by
1305 setting "memory_corruption_check=1" on the kernel command
1306 line. By default it scans the low 64k of memory every 60
1307 seconds; see the memory_corruption_check_size and
1308 memory_corruption_check_period parameters in
1309 Documentation/kernel-parameters.txt to adjust this.
1311 When enabled with the default parameters, this option has
1312 almost no overhead, as it reserves a relatively small amount
1313 of memory and scans it infrequently. It both detects corruption
1314 and prevents it from affecting the running system.
1316 It is, however, intended as a diagnostic tool; if repeatable
1317 BIOS-originated corruption always affects the same memory,
1318 you can use memmap= to prevent the kernel from using that
1321 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1322 bool "Set the default setting of memory_corruption_check"
1323 depends on X86_CHECK_BIOS_CORRUPTION
1326 Set whether the default state of memory_corruption_check is
1329 config X86_RESERVE_LOW_64K
1330 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1333 Reserve the first 64K of physical RAM on BIOSes that are known
1334 to potentially corrupt that memory range. A numbers of BIOSes are
1335 known to utilize this area during suspend/resume, so it must not
1336 be used by the kernel.
1338 Set this to N if you are absolutely sure that you trust the BIOS
1339 to get all its memory reservations and usages right.
1341 If you have doubts about the BIOS (e.g. suspend/resume does not
1342 work or there's kernel crashes after certain hardware hotplug
1343 events) and it's not AMI or Phoenix, then you might want to enable
1344 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1345 corruption patterns.
1349 config MATH_EMULATION
1351 prompt "Math emulation" if X86_32
1353 Linux can emulate a math coprocessor (used for floating point
1354 operations) if you don't have one. 486DX and Pentium processors have
1355 a math coprocessor built in, 486SX and 386 do not, unless you added
1356 a 487DX or 387, respectively. (The messages during boot time can
1357 give you some hints here ["man dmesg"].) Everyone needs either a
1358 coprocessor or this emulation.
1360 If you don't have a math coprocessor, you need to say Y here; if you
1361 say Y here even though you have a coprocessor, the coprocessor will
1362 be used nevertheless. (This behavior can be changed with the kernel
1363 command line option "no387", which comes handy if your coprocessor
1364 is broken. Try "man bootparam" or see the documentation of your boot
1365 loader (lilo or loadlin) about how to pass options to the kernel at
1366 boot time.) This means that it is a good idea to say Y here if you
1367 intend to use this kernel on different machines.
1369 More information about the internals of the Linux math coprocessor
1370 emulation can be found in <file:arch/x86/math-emu/README>.
1372 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1373 kernel, it won't hurt.
1378 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1380 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1381 the Memory Type Range Registers (MTRRs) may be used to control
1382 processor access to memory ranges. This is most useful if you have
1383 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1384 allows bus write transfers to be combined into a larger transfer
1385 before bursting over the PCI/AGP bus. This can increase performance
1386 of image write operations 2.5 times or more. Saying Y here creates a
1387 /proc/mtrr file which may be used to manipulate your processor's
1388 MTRRs. Typically the X server should use this.
1390 This code has a reasonably generic interface so that similar
1391 control registers on other processors can be easily supported
1394 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1395 Registers (ARRs) which provide a similar functionality to MTRRs. For
1396 these, the ARRs are used to emulate the MTRRs.
1397 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1398 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1399 write-combining. All of these processors are supported by this code
1400 and it makes sense to say Y here if you have one of them.
1402 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1403 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1404 can lead to all sorts of problems, so it's good to say Y here.
1406 You can safely say Y even if your machine doesn't have MTRRs, you'll
1407 just add about 9 KB to your kernel.
1409 See <file:Documentation/x86/mtrr.txt> for more information.
1411 config MTRR_SANITIZER
1413 prompt "MTRR cleanup support"
1416 Convert MTRR layout from continuous to discrete, so X drivers can
1417 add writeback entries.
1419 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1420 The largest mtrr entry size for a continuous block can be set with
1425 config MTRR_SANITIZER_ENABLE_DEFAULT
1426 int "MTRR cleanup enable value (0-1)"
1429 depends on MTRR_SANITIZER
1431 Enable mtrr cleanup default value
1433 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1434 int "MTRR cleanup spare reg num (0-7)"
1437 depends on MTRR_SANITIZER
1439 mtrr cleanup spare entries default, it can be changed via
1440 mtrr_spare_reg_nr=N on the kernel command line.
1445 prompt "x86 PAT support" if EMBEDDED
1448 Use PAT attributes to setup page level cache control.
1450 PATs are the modern equivalents of MTRRs and are much more
1451 flexible than MTRRs.
1453 Say N here if you see bootup problems (boot crash, boot hang,
1454 spontaneous reboots) or a non-working video driver.
1458 config ARCH_USES_PG_UNCACHED
1463 bool "EFI runtime service support"
1466 This enables the kernel to use EFI runtime services that are
1467 available (such as the EFI variable services).
1469 This option is only useful on systems that have EFI firmware.
1470 In addition, you should use the latest ELILO loader available
1471 at <http://elilo.sourceforge.net> in order to take advantage
1472 of EFI runtime services. However, even with this option, the
1473 resultant kernel should continue to boot on existing non-EFI
1478 prompt "Enable seccomp to safely compute untrusted bytecode"
1480 This kernel feature is useful for number crunching applications
1481 that may need to compute untrusted bytecode during their
1482 execution. By using pipes or other transports made available to
1483 the process as file descriptors supporting the read/write
1484 syscalls, it's possible to isolate those applications in
1485 their own address space using seccomp. Once seccomp is
1486 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1487 and the task is only allowed to execute a few safe syscalls
1488 defined by each seccomp mode.
1490 If unsure, say Y. Only embedded should say N here.
1492 config CC_STACKPROTECTOR
1493 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1495 This option turns on the -fstack-protector GCC feature. This
1496 feature puts, at the beginning of functions, a canary value on
1497 the stack just before the return address, and validates
1498 the value just before actually returning. Stack based buffer
1499 overflows (that need to overwrite this return address) now also
1500 overwrite the canary, which gets detected and the attack is then
1501 neutralized via a kernel panic.
1503 This feature requires gcc version 4.2 or above, or a distribution
1504 gcc with the feature backported. Older versions are automatically
1505 detected and for those versions, this configuration option is
1506 ignored. (and a warning is printed during bootup)
1508 source kernel/Kconfig.hz
1511 bool "kexec system call"
1513 kexec is a system call that implements the ability to shutdown your
1514 current kernel, and to start another kernel. It is like a reboot
1515 but it is independent of the system firmware. And like a reboot
1516 you can start any kernel with it, not just Linux.
1518 The name comes from the similarity to the exec system call.
1520 It is an ongoing process to be certain the hardware in a machine
1521 is properly shutdown, so do not be surprised if this code does not
1522 initially work for you. It may help to enable device hotplugging
1523 support. As of this writing the exact hardware interface is
1524 strongly in flux, so no good recommendation can be made.
1527 bool "kernel crash dumps"
1528 depends on X86_64 || (X86_32 && HIGHMEM)
1530 Generate crash dump after being started by kexec.
1531 This should be normally only set in special crash dump kernels
1532 which are loaded in the main kernel with kexec-tools into
1533 a specially reserved region and then later executed after
1534 a crash by kdump/kexec. The crash dump kernel must be compiled
1535 to a memory address not used by the main kernel or BIOS using
1536 PHYSICAL_START, or it must be built as a relocatable image
1537 (CONFIG_RELOCATABLE=y).
1538 For more details see Documentation/kdump/kdump.txt
1541 bool "kexec jump (EXPERIMENTAL)"
1542 depends on EXPERIMENTAL
1543 depends on KEXEC && HIBERNATION
1545 Jump between original kernel and kexeced kernel and invoke
1546 code in physical address mode via KEXEC
1548 config PHYSICAL_START
1549 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1552 This gives the physical address where the kernel is loaded.
1554 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1555 bzImage will decompress itself to above physical address and
1556 run from there. Otherwise, bzImage will run from the address where
1557 it has been loaded by the boot loader and will ignore above physical
1560 In normal kdump cases one does not have to set/change this option
1561 as now bzImage can be compiled as a completely relocatable image
1562 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1563 address. This option is mainly useful for the folks who don't want
1564 to use a bzImage for capturing the crash dump and want to use a
1565 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1566 to be specifically compiled to run from a specific memory area
1567 (normally a reserved region) and this option comes handy.
1569 So if you are using bzImage for capturing the crash dump,
1570 leave the value here unchanged to 0x1000000 and set
1571 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1572 for capturing the crash dump change this value to start of
1573 the reserved region. In other words, it can be set based on
1574 the "X" value as specified in the "crashkernel=YM@XM"
1575 command line boot parameter passed to the panic-ed
1576 kernel. Please take a look at Documentation/kdump/kdump.txt
1577 for more details about crash dumps.
1579 Usage of bzImage for capturing the crash dump is recommended as
1580 one does not have to build two kernels. Same kernel can be used
1581 as production kernel and capture kernel. Above option should have
1582 gone away after relocatable bzImage support is introduced. But it
1583 is present because there are users out there who continue to use
1584 vmlinux for dump capture. This option should go away down the
1587 Don't change this unless you know what you are doing.
1590 bool "Build a relocatable kernel"
1593 This builds a kernel image that retains relocation information
1594 so it can be loaded someplace besides the default 1MB.
1595 The relocations tend to make the kernel binary about 10% larger,
1596 but are discarded at runtime.
1598 One use is for the kexec on panic case where the recovery kernel
1599 must live at a different physical address than the primary
1602 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1603 it has been loaded at and the compile time physical address
1604 (CONFIG_PHYSICAL_START) is ignored.
1606 # Relocation on x86-32 needs some additional build support
1607 config X86_NEED_RELOCS
1609 depends on X86_32 && RELOCATABLE
1611 config PHYSICAL_ALIGN
1613 prompt "Alignment value to which kernel should be aligned" if X86_32
1615 range 0x2000 0x1000000
1617 This value puts the alignment restrictions on physical address
1618 where kernel is loaded and run from. Kernel is compiled for an
1619 address which meets above alignment restriction.
1621 If bootloader loads the kernel at a non-aligned address and
1622 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1623 address aligned to above value and run from there.
1625 If bootloader loads the kernel at a non-aligned address and
1626 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1627 load address and decompress itself to the address it has been
1628 compiled for and run from there. The address for which kernel is
1629 compiled already meets above alignment restrictions. Hence the
1630 end result is that kernel runs from a physical address meeting
1631 above alignment restrictions.
1633 Don't change this unless you know what you are doing.
1636 bool "Support for hot-pluggable CPUs"
1637 depends on SMP && HOTPLUG
1639 Say Y here to allow turning CPUs off and on. CPUs can be
1640 controlled through /sys/devices/system/cpu.
1641 ( Note: power management support will enable this option
1642 automatically on SMP systems. )
1643 Say N if you want to disable CPU hotplug.
1647 prompt "Compat VDSO support"
1648 depends on X86_32 || IA32_EMULATION
1650 Map the 32-bit VDSO to the predictable old-style address too.
1652 Say N here if you are running a sufficiently recent glibc
1653 version (2.3.3 or later), to remove the high-mapped
1654 VDSO mapping and to exclusively use the randomized VDSO.
1659 bool "Built-in kernel command line"
1662 Allow for specifying boot arguments to the kernel at
1663 build time. On some systems (e.g. embedded ones), it is
1664 necessary or convenient to provide some or all of the
1665 kernel boot arguments with the kernel itself (that is,
1666 to not rely on the boot loader to provide them.)
1668 To compile command line arguments into the kernel,
1669 set this option to 'Y', then fill in the
1670 the boot arguments in CONFIG_CMDLINE.
1672 Systems with fully functional boot loaders (i.e. non-embedded)
1673 should leave this option set to 'N'.
1676 string "Built-in kernel command string"
1677 depends on CMDLINE_BOOL
1680 Enter arguments here that should be compiled into the kernel
1681 image and used at boot time. If the boot loader provides a
1682 command line at boot time, it is appended to this string to
1683 form the full kernel command line, when the system boots.
1685 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1686 change this behavior.
1688 In most cases, the command line (whether built-in or provided
1689 by the boot loader) should specify the device for the root
1692 config CMDLINE_OVERRIDE
1693 bool "Built-in command line overrides boot loader arguments"
1695 depends on CMDLINE_BOOL
1697 Set this option to 'Y' to have the kernel ignore the boot loader
1698 command line, and use ONLY the built-in command line.
1700 This is used to work around broken boot loaders. This should
1701 be set to 'N' under normal conditions.
1705 config ARCH_ENABLE_MEMORY_HOTPLUG
1707 depends on X86_64 || (X86_32 && HIGHMEM)
1709 config ARCH_ENABLE_MEMORY_HOTREMOVE
1711 depends on MEMORY_HOTPLUG
1713 config HAVE_ARCH_EARLY_PFN_TO_NID
1717 menu "Power management and ACPI options"
1719 config ARCH_HIBERNATION_HEADER
1721 depends on X86_64 && HIBERNATION
1723 source "kernel/power/Kconfig"
1725 source "drivers/acpi/Kconfig"
1727 source "drivers/sfi/Kconfig"
1732 depends on APM || APM_MODULE
1735 tristate "APM (Advanced Power Management) BIOS support"
1736 depends on X86_32 && PM_SLEEP
1738 APM is a BIOS specification for saving power using several different
1739 techniques. This is mostly useful for battery powered laptops with
1740 APM compliant BIOSes. If you say Y here, the system time will be
1741 reset after a RESUME operation, the /proc/apm device will provide
1742 battery status information, and user-space programs will receive
1743 notification of APM "events" (e.g. battery status change).
1745 If you select "Y" here, you can disable actual use of the APM
1746 BIOS by passing the "apm=off" option to the kernel at boot time.
1748 Note that the APM support is almost completely disabled for
1749 machines with more than one CPU.
1751 In order to use APM, you will need supporting software. For location
1752 and more information, read <file:Documentation/power/pm.txt> and the
1753 Battery Powered Linux mini-HOWTO, available from
1754 <http://www.tldp.org/docs.html#howto>.
1756 This driver does not spin down disk drives (see the hdparm(8)
1757 manpage ("man 8 hdparm") for that), and it doesn't turn off
1758 VESA-compliant "green" monitors.
1760 This driver does not support the TI 4000M TravelMate and the ACER
1761 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1762 desktop machines also don't have compliant BIOSes, and this driver
1763 may cause those machines to panic during the boot phase.
1765 Generally, if you don't have a battery in your machine, there isn't
1766 much point in using this driver and you should say N. If you get
1767 random kernel OOPSes or reboots that don't seem to be related to
1768 anything, try disabling/enabling this option (or disabling/enabling
1771 Some other things you should try when experiencing seemingly random,
1774 1) make sure that you have enough swap space and that it is
1776 2) pass the "no-hlt" option to the kernel
1777 3) switch on floating point emulation in the kernel and pass
1778 the "no387" option to the kernel
1779 4) pass the "floppy=nodma" option to the kernel
1780 5) pass the "mem=4M" option to the kernel (thereby disabling
1781 all but the first 4 MB of RAM)
1782 6) make sure that the CPU is not over clocked.
1783 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1784 8) disable the cache from your BIOS settings
1785 9) install a fan for the video card or exchange video RAM
1786 10) install a better fan for the CPU
1787 11) exchange RAM chips
1788 12) exchange the motherboard.
1790 To compile this driver as a module, choose M here: the
1791 module will be called apm.
1795 config APM_IGNORE_USER_SUSPEND
1796 bool "Ignore USER SUSPEND"
1798 This option will ignore USER SUSPEND requests. On machines with a
1799 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1800 series notebooks, it is necessary to say Y because of a BIOS bug.
1802 config APM_DO_ENABLE
1803 bool "Enable PM at boot time"
1805 Enable APM features at boot time. From page 36 of the APM BIOS
1806 specification: "When disabled, the APM BIOS does not automatically
1807 power manage devices, enter the Standby State, enter the Suspend
1808 State, or take power saving steps in response to CPU Idle calls."
1809 This driver will make CPU Idle calls when Linux is idle (unless this
1810 feature is turned off -- see "Do CPU IDLE calls", below). This
1811 should always save battery power, but more complicated APM features
1812 will be dependent on your BIOS implementation. You may need to turn
1813 this option off if your computer hangs at boot time when using APM
1814 support, or if it beeps continuously instead of suspending. Turn
1815 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1816 T400CDT. This is off by default since most machines do fine without
1820 bool "Make CPU Idle calls when idle"
1822 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1823 On some machines, this can activate improved power savings, such as
1824 a slowed CPU clock rate, when the machine is idle. These idle calls
1825 are made after the idle loop has run for some length of time (e.g.,
1826 333 mS). On some machines, this will cause a hang at boot time or
1827 whenever the CPU becomes idle. (On machines with more than one CPU,
1828 this option does nothing.)
1830 config APM_DISPLAY_BLANK
1831 bool "Enable console blanking using APM"
1833 Enable console blanking using the APM. Some laptops can use this to
1834 turn off the LCD backlight when the screen blanker of the Linux
1835 virtual console blanks the screen. Note that this is only used by
1836 the virtual console screen blanker, and won't turn off the backlight
1837 when using the X Window system. This also doesn't have anything to
1838 do with your VESA-compliant power-saving monitor. Further, this
1839 option doesn't work for all laptops -- it might not turn off your
1840 backlight at all, or it might print a lot of errors to the console,
1841 especially if you are using gpm.
1843 config APM_ALLOW_INTS
1844 bool "Allow interrupts during APM BIOS calls"
1846 Normally we disable external interrupts while we are making calls to
1847 the APM BIOS as a measure to lessen the effects of a badly behaving
1848 BIOS implementation. The BIOS should reenable interrupts if it
1849 needs to. Unfortunately, some BIOSes do not -- especially those in
1850 many of the newer IBM Thinkpads. If you experience hangs when you
1851 suspend, try setting this to Y. Otherwise, say N.
1855 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1857 source "drivers/cpuidle/Kconfig"
1859 source "drivers/idle/Kconfig"
1864 menu "Bus options (PCI etc.)"
1869 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1871 Find out whether you have a PCI motherboard. PCI is the name of a
1872 bus system, i.e. the way the CPU talks to the other stuff inside
1873 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1874 VESA. If you have PCI, say Y, otherwise N.
1877 prompt "PCI access mode"
1878 depends on X86_32 && PCI
1881 On PCI systems, the BIOS can be used to detect the PCI devices and
1882 determine their configuration. However, some old PCI motherboards
1883 have BIOS bugs and may crash if this is done. Also, some embedded
1884 PCI-based systems don't have any BIOS at all. Linux can also try to
1885 detect the PCI hardware directly without using the BIOS.
1887 With this option, you can specify how Linux should detect the
1888 PCI devices. If you choose "BIOS", the BIOS will be used,
1889 if you choose "Direct", the BIOS won't be used, and if you
1890 choose "MMConfig", then PCI Express MMCONFIG will be used.
1891 If you choose "Any", the kernel will try MMCONFIG, then the
1892 direct access method and falls back to the BIOS if that doesn't
1893 work. If unsure, go with the default, which is "Any".
1898 config PCI_GOMMCONFIG
1915 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1917 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1920 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1924 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1928 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1935 bool "Support mmconfig PCI config space access"
1936 depends on X86_64 && PCI && ACPI
1939 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1940 depends on PCI_MSI && ACPI && EXPERIMENTAL
1942 DMA remapping (DMAR) devices support enables independent address
1943 translations for Direct Memory Access (DMA) from devices.
1944 These DMA remapping devices are reported via ACPI tables
1945 and include PCI device scope covered by these DMA
1948 config DMAR_DEFAULT_ON
1950 prompt "Enable DMA Remapping Devices by default"
1953 Selecting this option will enable a DMAR device at boot time if
1954 one is found. If this option is not selected, DMAR support can
1955 be enabled by passing intel_iommu=on to the kernel. It is
1956 recommended you say N here while the DMAR code remains
1959 config DMAR_BROKEN_GFX_WA
1961 prompt "Workaround broken graphics drivers (going away soon)"
1962 depends on DMAR && BROKEN
1964 Current Graphics drivers tend to use physical address
1965 for DMA and avoid using DMA APIs. Setting this config
1966 option permits the IOMMU driver to set a unity map for
1967 all the OS-visible memory. Hence the driver can continue
1968 to use physical addresses for DMA, at least until this
1969 option is removed in the 2.6.32 kernel.
1971 config DMAR_FLOPPY_WA
1975 Floppy disk drivers are known to bypass DMA API calls
1976 thereby failing to work when IOMMU is enabled. This
1977 workaround will setup a 1:1 mapping for the first
1978 16MiB to make floppy (an ISA device) work.
1981 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1982 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1984 Supports Interrupt remapping for IO-APIC and MSI devices.
1985 To use x2apic mode in the CPU's which support x2APIC enhancements or
1986 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1988 source "drivers/pci/pcie/Kconfig"
1990 source "drivers/pci/Kconfig"
1992 # x86_64 have no ISA slots, but do have ISA-style DMA.
2001 Find out whether you have ISA slots on your motherboard. ISA is the
2002 name of a bus system, i.e. the way the CPU talks to the other stuff
2003 inside your box. Other bus systems are PCI, EISA, MicroChannel
2004 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2005 newer boards don't support it. If you have ISA, say Y, otherwise N.
2011 The Extended Industry Standard Architecture (EISA) bus was
2012 developed as an open alternative to the IBM MicroChannel bus.
2014 The EISA bus provided some of the features of the IBM MicroChannel
2015 bus while maintaining backward compatibility with cards made for
2016 the older ISA bus. The EISA bus saw limited use between 1988 and
2017 1995 when it was made obsolete by the PCI bus.
2019 Say Y here if you are building a kernel for an EISA-based machine.
2023 source "drivers/eisa/Kconfig"
2028 MicroChannel Architecture is found in some IBM PS/2 machines and
2029 laptops. It is a bus system similar to PCI or ISA. See
2030 <file:Documentation/mca.txt> (and especially the web page given
2031 there) before attempting to build an MCA bus kernel.
2033 source "drivers/mca/Kconfig"
2036 tristate "NatSemi SCx200 support"
2038 This provides basic support for National Semiconductor's
2039 (now AMD's) Geode processors. The driver probes for the
2040 PCI-IDs of several on-chip devices, so its a good dependency
2041 for other scx200_* drivers.
2043 If compiled as a module, the driver is named scx200.
2045 config SCx200HR_TIMER
2046 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2047 depends on SCx200 && GENERIC_TIME
2050 This driver provides a clocksource built upon the on-chip
2051 27MHz high-resolution timer. Its also a workaround for
2052 NSC Geode SC-1100's buggy TSC, which loses time when the
2053 processor goes idle (as is done by the scheduler). The
2054 other workaround is idle=poll boot option.
2057 bool "One Laptop Per Child support"
2061 Add support for detecting the unique features of the OLPC
2068 depends on CPU_SUP_AMD && PCI
2070 source "drivers/pcmcia/Kconfig"
2072 source "drivers/pci/hotplug/Kconfig"
2077 menu "Executable file formats / Emulations"
2079 source "fs/Kconfig.binfmt"
2081 config IA32_EMULATION
2082 bool "IA32 Emulation"
2084 select COMPAT_BINFMT_ELF
2086 Include code to run 32-bit programs under a 64-bit kernel. You should
2087 likely turn this on, unless you're 100% sure that you don't have any
2088 32-bit programs left.
2091 tristate "IA32 a.out support"
2092 depends on IA32_EMULATION
2094 Support old a.out binaries in the 32bit emulation.
2098 depends on IA32_EMULATION
2100 config COMPAT_FOR_U64_ALIGNMENT
2104 config SYSVIPC_COMPAT
2106 depends on COMPAT && SYSVIPC
2111 config HAVE_ATOMIC_IOMAP
2115 source "net/Kconfig"
2117 source "drivers/Kconfig"
2119 source "drivers/firmware/Kconfig"
2123 source "arch/x86/Kconfig.debug"
2125 source "security/Kconfig"
2127 source "crypto/Kconfig"
2129 source "arch/x86/kvm/Kconfig"
2131 source "lib/Kconfig"