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
58 select HAVE_PERF_EVENTS_NMI
60 select HAVE_ARCH_KMEMCHECK
61 select HAVE_USER_RETURN_NOTIFIER
62 select HAVE_ARCH_JUMP_LABEL if !CC_OPTIMIZE_FOR_SIZE
64 config INSTRUCTION_DECODER
65 def_bool (KPROBES || PERF_EVENTS)
69 default "elf32-i386" if X86_32
70 default "elf64-x86-64" if X86_64
74 default "arch/x86/configs/i386_defconfig" if X86_32
75 default "arch/x86/configs/x86_64_defconfig" if X86_64
77 config GENERIC_CMOS_UPDATE
80 config CLOCKSOURCE_WATCHDOG
83 config GENERIC_CLOCKEVENTS
86 config GENERIC_CLOCKEVENTS_BROADCAST
88 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
90 config LOCKDEP_SUPPORT
93 config STACKTRACE_SUPPORT
96 config HAVE_LATENCYTOP_SUPPORT
108 config NEED_DMA_MAP_STATE
109 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
111 config NEED_SG_DMA_LENGTH
114 config GENERIC_ISA_DMA
123 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
125 config GENERIC_BUG_RELATIVE_POINTERS
128 config GENERIC_HWEIGHT
134 config ARCH_MAY_HAVE_PC_FDC
137 config RWSEM_GENERIC_SPINLOCK
140 config RWSEM_XCHGADD_ALGORITHM
143 config ARCH_HAS_CPU_IDLE_WAIT
146 config GENERIC_CALIBRATE_DELAY
149 config GENERIC_TIME_VSYSCALL
153 config ARCH_HAS_CPU_RELAX
156 config ARCH_HAS_DEFAULT_IDLE
159 config ARCH_HAS_CACHE_LINE_SIZE
162 config HAVE_SETUP_PER_CPU_AREA
165 config NEED_PER_CPU_EMBED_FIRST_CHUNK
168 config NEED_PER_CPU_PAGE_FIRST_CHUNK
171 config HAVE_CPUMASK_OF_CPU_MAP
174 config ARCH_HIBERNATION_POSSIBLE
177 config ARCH_SUSPEND_POSSIBLE
184 config ARCH_POPULATES_NODE_MAP
191 config ARCH_SUPPORTS_OPTIMIZED_INLINING
194 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
197 config HAVE_EARLY_RES
200 config HAVE_INTEL_TXT
202 depends on EXPERIMENTAL && DMAR && ACPI
204 # Use the generic interrupt handling code in kernel/irq/:
205 config GENERIC_HARDIRQS
208 config GENERIC_HARDIRQS_NO__DO_IRQ
211 config GENERIC_IRQ_PROBE
214 config GENERIC_PENDING_IRQ
216 depends on GENERIC_HARDIRQS && SMP
218 config USE_GENERIC_SMP_HELPERS
224 depends on X86_32 && SMP
228 depends on X86_64 && SMP
234 config X86_TRAMPOLINE
236 depends on SMP || (64BIT && ACPI_SLEEP)
238 config X86_32_LAZY_GS
240 depends on X86_32 && !CC_STACKPROTECTOR
242 config ARCH_HWEIGHT_CFLAGS
244 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
245 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
250 config ARCH_CPU_PROBE_RELEASE
252 depends on HOTPLUG_CPU
254 source "init/Kconfig"
255 source "kernel/Kconfig.freezer"
257 menu "Processor type and features"
259 source "kernel/time/Kconfig"
262 bool "Symmetric multi-processing support"
264 This enables support for systems with more than one CPU. If you have
265 a system with only one CPU, like most personal computers, say N. If
266 you have a system with more than one CPU, say Y.
268 If you say N here, the kernel will run on single and multiprocessor
269 machines, but will use only one CPU of a multiprocessor machine. If
270 you say Y here, the kernel will run on many, but not all,
271 singleprocessor machines. On a singleprocessor machine, the kernel
272 will run faster if you say N here.
274 Note that if you say Y here and choose architecture "586" or
275 "Pentium" under "Processor family", the kernel will not work on 486
276 architectures. Similarly, multiprocessor kernels for the "PPro"
277 architecture may not work on all Pentium based boards.
279 People using multiprocessor machines who say Y here should also say
280 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
281 Management" code will be disabled if you say Y here.
283 See also <file:Documentation/i386/IO-APIC.txt>,
284 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
285 <http://www.tldp.org/docs.html#howto>.
287 If you don't know what to do here, say N.
290 bool "Support x2apic"
291 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
293 This enables x2apic support on CPUs that have this feature.
295 This allows 32-bit apic IDs (so it can support very large systems),
296 and accesses the local apic via MSRs not via mmio.
298 If you don't know what to do here, say N.
301 bool "Support sparse irq numbering"
302 depends on PCI_MSI || HT_IRQ
304 This enables support for sparse irqs. This is useful for distro
305 kernels that want to define a high CONFIG_NR_CPUS value but still
306 want to have low kernel memory footprint on smaller machines.
308 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
309 out the irq_desc[] array in a more NUMA-friendly way. )
311 If you don't know what to do here, say N.
315 depends on SPARSE_IRQ && NUMA
318 bool "Enable MPS table" if ACPI
320 depends on X86_LOCAL_APIC
322 For old smp systems that do not have proper acpi support. Newer systems
323 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
326 bool "Support for big SMP systems with more than 8 CPUs"
327 depends on X86_32 && SMP
329 This option is needed for the systems that have more than 8 CPUs
332 config X86_EXTENDED_PLATFORM
333 bool "Support for extended (non-PC) x86 platforms"
336 If you disable this option then the kernel will only support
337 standard PC platforms. (which covers the vast majority of
340 If you enable this option then you'll be able to select support
341 for the following (non-PC) 32 bit x86 platforms:
345 SGI 320/540 (Visual Workstation)
346 Summit/EXA (IBM x440)
347 Unisys ES7000 IA32 series
348 Moorestown MID devices
350 If you have one of these systems, or if you want to build a
351 generic distribution kernel, say Y here - otherwise say N.
355 config X86_EXTENDED_PLATFORM
356 bool "Support for extended (non-PC) x86 platforms"
359 If you disable this option then the kernel will only support
360 standard PC platforms. (which covers the vast majority of
363 If you enable this option then you'll be able to select support
364 for the following (non-PC) 64 bit x86 platforms:
368 If you have one of these systems, or if you want to build a
369 generic distribution kernel, say Y here - otherwise say N.
371 # This is an alphabetically sorted list of 64 bit extended platforms
372 # Please maintain the alphabetic order if and when there are additions
377 depends on X86_64 && PCI
378 depends on X86_EXTENDED_PLATFORM
380 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
381 supposed to run on these EM64T-based machines. Only choose this option
382 if you have one of these machines.
385 bool "SGI Ultraviolet"
387 depends on X86_EXTENDED_PLATFORM
389 depends on X86_X2APIC
391 This option is needed in order to support SGI Ultraviolet systems.
392 If you don't have one of these, you should say N here.
394 # Following is an alphabetically sorted list of 32 bit extended platforms
395 # Please maintain the alphabetic order if and when there are additions
400 depends on X86_EXTENDED_PLATFORM
402 Select this for an AMD Elan processor.
404 Do not use this option for K6/Athlon/Opteron processors!
406 If unsure, choose "PC-compatible" instead.
409 bool "Moorestown MID platform"
413 depends on X86_EXTENDED_PLATFORM
414 depends on X86_IO_APIC
417 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
418 Internet Device(MID) platform. Moorestown consists of two chips:
419 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
420 Unlike standard x86 PCs, Moorestown does not have many legacy devices
421 nor standard legacy replacement devices/features. e.g. Moorestown does
422 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
425 bool "RDC R-321x SoC"
427 depends on X86_EXTENDED_PLATFORM
429 select X86_REBOOTFIXUPS
431 This option is needed for RDC R-321x system-on-chip, also known
433 If you don't have one of these chips, you should say N here.
435 config X86_32_NON_STANDARD
436 bool "Support non-standard 32-bit SMP architectures"
437 depends on X86_32 && SMP
438 depends on X86_EXTENDED_PLATFORM
440 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
441 subarchitectures. It is intended for a generic binary kernel.
442 if you select them all, kernel will probe it one by one. and will
445 # Alphabetically sorted list of Non standard 32 bit platforms
448 bool "NUMAQ (IBM/Sequent)"
449 depends on X86_32_NON_STANDARD
454 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
455 NUMA multiquad box. This changes the way that processors are
456 bootstrapped, and uses Clustered Logical APIC addressing mode instead
457 of Flat Logical. You will need a new lynxer.elf file to flash your
458 firmware with - send email to <Martin.Bligh@us.ibm.com>.
460 config X86_SUPPORTS_MEMORY_FAILURE
462 # MCE code calls memory_failure():
464 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
465 depends on !X86_NUMAQ
466 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
467 depends on X86_64 || !SPARSEMEM
468 select ARCH_SUPPORTS_MEMORY_FAILURE
471 bool "SGI 320/540 (Visual Workstation)"
472 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
473 depends on X86_32_NON_STANDARD
475 The SGI Visual Workstation series is an IA32-based workstation
476 based on SGI systems chips with some legacy PC hardware attached.
478 Say Y here to create a kernel to run on the SGI 320 or 540.
480 A kernel compiled for the Visual Workstation will run on general
481 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
484 bool "Summit/EXA (IBM x440)"
485 depends on X86_32_NON_STANDARD
487 This option is needed for IBM systems that use the Summit/EXA chipset.
488 In particular, it is needed for the x440.
491 bool "Unisys ES7000 IA32 series"
492 depends on X86_32_NON_STANDARD && X86_BIGSMP
494 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
495 supposed to run on an IA32-based Unisys ES7000 system.
497 config SCHED_OMIT_FRAME_POINTER
499 prompt "Single-depth WCHAN output"
502 Calculate simpler /proc/<PID>/wchan values. If this option
503 is disabled then wchan values will recurse back to the
504 caller function. This provides more accurate wchan values,
505 at the expense of slightly more scheduling overhead.
507 If in doubt, say "Y".
509 menuconfig PARAVIRT_GUEST
510 bool "Paravirtualized guest support"
512 Say Y here to get to see options related to running Linux under
513 various hypervisors. This option alone does not add any kernel code.
515 If you say N, all options in this submenu will be skipped and disabled.
519 source "arch/x86/xen/Kconfig"
522 bool "VMI Guest support (DEPRECATED)"
526 VMI provides a paravirtualized interface to the VMware ESX server
527 (it could be used by other hypervisors in theory too, but is not
528 at the moment), by linking the kernel to a GPL-ed ROM module
529 provided by the hypervisor.
531 As of September 2009, VMware has started a phased retirement
532 of this feature from VMware's products. Please see
533 feature-removal-schedule.txt for details. If you are
534 planning to enable this option, please note that you cannot
535 live migrate a VMI enabled VM to a future VMware product,
536 which doesn't support VMI. So if you expect your kernel to
537 seamlessly migrate to newer VMware products, keep this
541 bool "KVM paravirtualized clock"
543 select PARAVIRT_CLOCK
545 Turning on this option will allow you to run a paravirtualized clock
546 when running over the KVM hypervisor. Instead of relying on a PIT
547 (or probably other) emulation by the underlying device model, the host
548 provides the guest with timing infrastructure such as time of day, and
552 bool "KVM Guest support"
555 This option enables various optimizations for running under the KVM
558 source "arch/x86/lguest/Kconfig"
561 bool "Enable paravirtualization code"
563 This changes the kernel so it can modify itself when it is run
564 under a hypervisor, potentially improving performance significantly
565 over full virtualization. However, when run without a hypervisor
566 the kernel is theoretically slower and slightly larger.
568 config PARAVIRT_SPINLOCKS
569 bool "Paravirtualization layer for spinlocks"
570 depends on PARAVIRT && SMP && EXPERIMENTAL
572 Paravirtualized spinlocks allow a pvops backend to replace the
573 spinlock implementation with something virtualization-friendly
574 (for example, block the virtual CPU rather than spinning).
576 Unfortunately the downside is an up to 5% performance hit on
577 native kernels, with various workloads.
579 If you are unsure how to answer this question, answer N.
581 config PARAVIRT_CLOCK
586 config PARAVIRT_DEBUG
587 bool "paravirt-ops debugging"
588 depends on PARAVIRT && DEBUG_KERNEL
590 Enable to debug paravirt_ops internals. Specifically, BUG if
591 a paravirt_op is missing when it is called.
595 bool "Disable Bootmem code"
597 Use early_res directly instead of bootmem before slab is ready.
598 - allocator (buddy) [generic]
599 - early allocator (bootmem) [generic]
600 - very early allocator (reserve_early*()) [x86]
601 - very very early allocator (early brk model) [x86]
602 So reduce one layer between early allocator to final allocator
608 This option adds a kernel parameter 'memtest', which allows memtest
610 memtest=0, mean disabled; -- default
611 memtest=1, mean do 1 test pattern;
613 memtest=4, mean do 4 test patterns.
614 If you are unsure how to answer this question, answer N.
616 config X86_SUMMIT_NUMA
618 depends on X86_32 && NUMA && X86_32_NON_STANDARD
620 config X86_CYCLONE_TIMER
622 depends on X86_32_NON_STANDARD
624 source "arch/x86/Kconfig.cpu"
628 prompt "HPET Timer Support" if X86_32
630 Use the IA-PC HPET (High Precision Event Timer) to manage
631 time in preference to the PIT and RTC, if a HPET is
633 HPET is the next generation timer replacing legacy 8254s.
634 The HPET provides a stable time base on SMP
635 systems, unlike the TSC, but it is more expensive to access,
636 as it is off-chip. You can find the HPET spec at
637 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
639 You can safely choose Y here. However, HPET will only be
640 activated if the platform and the BIOS support this feature.
641 Otherwise the 8254 will be used for timing services.
643 Choose N to continue using the legacy 8254 timer.
645 config HPET_EMULATE_RTC
647 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
651 prompt "Langwell APB Timer Support" if X86_MRST
653 APB timer is the replacement for 8254, HPET on X86 MID platforms.
654 The APBT provides a stable time base on SMP
655 systems, unlike the TSC, but it is more expensive to access,
656 as it is off-chip. APB timers are always running regardless of CPU
657 C states, they are used as per CPU clockevent device when possible.
659 # Mark as embedded because too many people got it wrong.
660 # The code disables itself when not needed.
663 bool "Enable DMI scanning" if EMBEDDED
665 Enabled scanning of DMI to identify machine quirks. Say Y
666 here unless you have verified that your setup is not
667 affected by entries in the DMI blacklist. Required by PNP
671 bool "GART IOMMU support" if EMBEDDED
674 depends on X86_64 && PCI && K8_NB
676 Support for full DMA access of devices with 32bit memory access only
677 on systems with more than 3GB. This is usually needed for USB,
678 sound, many IDE/SATA chipsets and some other devices.
679 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
680 based hardware IOMMU and a software bounce buffer based IOMMU used
681 on Intel systems and as fallback.
682 The code is only active when needed (enough memory and limited
683 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
687 bool "IBM Calgary IOMMU support"
689 depends on X86_64 && PCI && EXPERIMENTAL
691 Support for hardware IOMMUs in IBM's xSeries x366 and x460
692 systems. Needed to run systems with more than 3GB of memory
693 properly with 32-bit PCI devices that do not support DAC
694 (Double Address Cycle). Calgary also supports bus level
695 isolation, where all DMAs pass through the IOMMU. This
696 prevents them from going anywhere except their intended
697 destination. This catches hard-to-find kernel bugs and
698 mis-behaving drivers and devices that do not use the DMA-API
699 properly to set up their DMA buffers. The IOMMU can be
700 turned off at boot time with the iommu=off parameter.
701 Normally the kernel will make the right choice by itself.
704 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
706 prompt "Should Calgary be enabled by default?"
707 depends on CALGARY_IOMMU
709 Should Calgary be enabled by default? if you choose 'y', Calgary
710 will be used (if it exists). If you choose 'n', Calgary will not be
711 used even if it exists. If you choose 'n' and would like to use
712 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
716 bool "AMD IOMMU support"
719 depends on X86_64 && PCI && ACPI
721 With this option you can enable support for AMD IOMMU hardware in
722 your system. An IOMMU is a hardware component which provides
723 remapping of DMA memory accesses from devices. With an AMD IOMMU you
724 can isolate the the DMA memory of different devices and protect the
725 system from misbehaving device drivers or hardware.
727 You can find out if your system has an AMD IOMMU if you look into
728 your BIOS for an option to enable it or if you have an IVRS ACPI
731 config AMD_IOMMU_STATS
732 bool "Export AMD IOMMU statistics to debugfs"
736 This option enables code in the AMD IOMMU driver to collect various
737 statistics about whats happening in the driver and exports that
738 information to userspace via debugfs.
741 # need this always selected by IOMMU for the VIA workaround
745 Support for software bounce buffers used on x86-64 systems
746 which don't have a hardware IOMMU (e.g. the current generation
747 of Intel's x86-64 CPUs). Using this PCI devices which can only
748 access 32-bits of memory can be used on systems with more than
749 3 GB of memory. If unsure, say Y.
752 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
755 def_bool (AMD_IOMMU || DMAR)
758 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
759 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
760 select CPUMASK_OFFSTACK
762 Enable maximum number of CPUS and NUMA Nodes for this architecture.
766 int "Maximum number of CPUs" if SMP && !MAXSMP
767 range 2 8 if SMP && X86_32 && !X86_BIGSMP
768 range 2 512 if SMP && !MAXSMP
770 default "4096" if MAXSMP
771 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
774 This allows you to specify the maximum number of CPUs which this
775 kernel will support. The maximum supported value is 512 and the
776 minimum value which makes sense is 2.
778 This is purely to save memory - each supported CPU adds
779 approximately eight kilobytes to the kernel image.
782 bool "SMT (Hyperthreading) scheduler support"
785 SMT scheduler support improves the CPU scheduler's decision making
786 when dealing with Intel Pentium 4 chips with HyperThreading at a
787 cost of slightly increased overhead in some places. If unsure say
792 prompt "Multi-core scheduler support"
795 Multi-core scheduler support improves the CPU scheduler's decision
796 making when dealing with multi-core CPU chips at a cost of slightly
797 increased overhead in some places. If unsure say N here.
799 source "kernel/Kconfig.preempt"
802 bool "Local APIC support on uniprocessors"
803 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
805 A local APIC (Advanced Programmable Interrupt Controller) is an
806 integrated interrupt controller in the CPU. If you have a single-CPU
807 system which has a processor with a local APIC, you can say Y here to
808 enable and use it. If you say Y here even though your machine doesn't
809 have a local APIC, then the kernel will still run with no slowdown at
810 all. The local APIC supports CPU-generated self-interrupts (timer,
811 performance counters), and the NMI watchdog which detects hard
815 bool "IO-APIC support on uniprocessors"
816 depends on X86_UP_APIC
818 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
819 SMP-capable replacement for PC-style interrupt controllers. Most
820 SMP systems and many recent uniprocessor systems have one.
822 If you have a single-CPU system with an IO-APIC, you can say Y here
823 to use it. If you say Y here even though your machine doesn't have
824 an IO-APIC, then the kernel will still run with no slowdown at all.
826 config X86_LOCAL_APIC
828 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
832 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
834 config X86_VISWS_APIC
836 depends on X86_32 && X86_VISWS
838 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
839 bool "Reroute for broken boot IRQs"
840 depends on X86_IO_APIC
842 This option enables a workaround that fixes a source of
843 spurious interrupts. This is recommended when threaded
844 interrupt handling is used on systems where the generation of
845 superfluous "boot interrupts" cannot be disabled.
847 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
848 entry in the chipset's IO-APIC is masked (as, e.g. the RT
849 kernel does during interrupt handling). On chipsets where this
850 boot IRQ generation cannot be disabled, this workaround keeps
851 the original IRQ line masked so that only the equivalent "boot
852 IRQ" is delivered to the CPUs. The workaround also tells the
853 kernel to set up the IRQ handler on the boot IRQ line. In this
854 way only one interrupt is delivered to the kernel. Otherwise
855 the spurious second interrupt may cause the kernel to bring
856 down (vital) interrupt lines.
858 Only affects "broken" chipsets. Interrupt sharing may be
859 increased on these systems.
862 bool "Machine Check / overheating reporting"
864 Machine Check support allows the processor to notify the
865 kernel if it detects a problem (e.g. overheating, data corruption).
866 The action the kernel takes depends on the severity of the problem,
867 ranging from warning messages to halting the machine.
871 prompt "Intel MCE features"
872 depends on X86_MCE && X86_LOCAL_APIC
874 Additional support for intel specific MCE features such as
879 prompt "AMD MCE features"
880 depends on X86_MCE && X86_LOCAL_APIC
882 Additional support for AMD specific MCE features such as
883 the DRAM Error Threshold.
885 config X86_ANCIENT_MCE
886 bool "Support for old Pentium 5 / WinChip machine checks"
887 depends on X86_32 && X86_MCE
889 Include support for machine check handling on old Pentium 5 or WinChip
890 systems. These typically need to be enabled explicitely on the command
893 config X86_MCE_THRESHOLD
894 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 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"
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.
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.
1444 prompt "x86 PAT support" if EMBEDDED
1447 Use PAT attributes to setup page level cache control.
1449 PATs are the modern equivalents of MTRRs and are much more
1450 flexible than MTRRs.
1452 Say N here if you see bootup problems (boot crash, boot hang,
1453 spontaneous reboots) or a non-working video driver.
1457 config ARCH_USES_PG_UNCACHED
1462 bool "EFI runtime service support"
1465 This enables the kernel to use EFI runtime services that are
1466 available (such as the EFI variable services).
1468 This option is only useful on systems that have EFI firmware.
1469 In addition, you should use the latest ELILO loader available
1470 at <http://elilo.sourceforge.net> in order to take advantage
1471 of EFI runtime services. However, even with this option, the
1472 resultant kernel should continue to boot on existing non-EFI
1477 prompt "Enable seccomp to safely compute untrusted bytecode"
1479 This kernel feature is useful for number crunching applications
1480 that may need to compute untrusted bytecode during their
1481 execution. By using pipes or other transports made available to
1482 the process as file descriptors supporting the read/write
1483 syscalls, it's possible to isolate those applications in
1484 their own address space using seccomp. Once seccomp is
1485 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1486 and the task is only allowed to execute a few safe syscalls
1487 defined by each seccomp mode.
1489 If unsure, say Y. Only embedded should say N here.
1491 config CC_STACKPROTECTOR
1492 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1494 This option turns on the -fstack-protector GCC feature. This
1495 feature puts, at the beginning of functions, a canary value on
1496 the stack just before the return address, and validates
1497 the value just before actually returning. Stack based buffer
1498 overflows (that need to overwrite this return address) now also
1499 overwrite the canary, which gets detected and the attack is then
1500 neutralized via a kernel panic.
1502 This feature requires gcc version 4.2 or above, or a distribution
1503 gcc with the feature backported. Older versions are automatically
1504 detected and for those versions, this configuration option is
1505 ignored. (and a warning is printed during bootup)
1507 source kernel/Kconfig.hz
1510 bool "kexec system call"
1512 kexec is a system call that implements the ability to shutdown your
1513 current kernel, and to start another kernel. It is like a reboot
1514 but it is independent of the system firmware. And like a reboot
1515 you can start any kernel with it, not just Linux.
1517 The name comes from the similarity to the exec system call.
1519 It is an ongoing process to be certain the hardware in a machine
1520 is properly shutdown, so do not be surprised if this code does not
1521 initially work for you. It may help to enable device hotplugging
1522 support. As of this writing the exact hardware interface is
1523 strongly in flux, so no good recommendation can be made.
1526 bool "kernel crash dumps"
1527 depends on X86_64 || (X86_32 && HIGHMEM)
1529 Generate crash dump after being started by kexec.
1530 This should be normally only set in special crash dump kernels
1531 which are loaded in the main kernel with kexec-tools into
1532 a specially reserved region and then later executed after
1533 a crash by kdump/kexec. The crash dump kernel must be compiled
1534 to a memory address not used by the main kernel or BIOS using
1535 PHYSICAL_START, or it must be built as a relocatable image
1536 (CONFIG_RELOCATABLE=y).
1537 For more details see Documentation/kdump/kdump.txt
1540 bool "kexec jump (EXPERIMENTAL)"
1541 depends on EXPERIMENTAL
1542 depends on KEXEC && HIBERNATION
1544 Jump between original kernel and kexeced kernel and invoke
1545 code in physical address mode via KEXEC
1547 config PHYSICAL_START
1548 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1551 This gives the physical address where the kernel is loaded.
1553 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1554 bzImage will decompress itself to above physical address and
1555 run from there. Otherwise, bzImage will run from the address where
1556 it has been loaded by the boot loader and will ignore above physical
1559 In normal kdump cases one does not have to set/change this option
1560 as now bzImage can be compiled as a completely relocatable image
1561 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1562 address. This option is mainly useful for the folks who don't want
1563 to use a bzImage for capturing the crash dump and want to use a
1564 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1565 to be specifically compiled to run from a specific memory area
1566 (normally a reserved region) and this option comes handy.
1568 So if you are using bzImage for capturing the crash dump,
1569 leave the value here unchanged to 0x1000000 and set
1570 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1571 for capturing the crash dump change this value to start of
1572 the reserved region. In other words, it can be set based on
1573 the "X" value as specified in the "crashkernel=YM@XM"
1574 command line boot parameter passed to the panic-ed
1575 kernel. Please take a look at Documentation/kdump/kdump.txt
1576 for more details about crash dumps.
1578 Usage of bzImage for capturing the crash dump is recommended as
1579 one does not have to build two kernels. Same kernel can be used
1580 as production kernel and capture kernel. Above option should have
1581 gone away after relocatable bzImage support is introduced. But it
1582 is present because there are users out there who continue to use
1583 vmlinux for dump capture. This option should go away down the
1586 Don't change this unless you know what you are doing.
1589 bool "Build a relocatable kernel"
1592 This builds a kernel image that retains relocation information
1593 so it can be loaded someplace besides the default 1MB.
1594 The relocations tend to make the kernel binary about 10% larger,
1595 but are discarded at runtime.
1597 One use is for the kexec on panic case where the recovery kernel
1598 must live at a different physical address than the primary
1601 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1602 it has been loaded at and the compile time physical address
1603 (CONFIG_PHYSICAL_START) is ignored.
1605 # Relocation on x86-32 needs some additional build support
1606 config X86_NEED_RELOCS
1608 depends on X86_32 && RELOCATABLE
1610 config PHYSICAL_ALIGN
1611 hex "Alignment value to which kernel should be aligned" if X86_32
1613 range 0x2000 0x1000000
1615 This value puts the alignment restrictions on physical address
1616 where kernel is loaded and run from. Kernel is compiled for an
1617 address which meets above alignment restriction.
1619 If bootloader loads the kernel at a non-aligned address and
1620 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1621 address aligned to above value and run from there.
1623 If bootloader loads the kernel at a non-aligned address and
1624 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1625 load address and decompress itself to the address it has been
1626 compiled for and run from there. The address for which kernel is
1627 compiled already meets above alignment restrictions. Hence the
1628 end result is that kernel runs from a physical address meeting
1629 above alignment restrictions.
1631 Don't change this unless you know what you are doing.
1634 bool "Support for hot-pluggable CPUs"
1635 depends on SMP && HOTPLUG
1637 Say Y here to allow turning CPUs off and on. CPUs can be
1638 controlled through /sys/devices/system/cpu.
1639 ( Note: power management support will enable this option
1640 automatically on SMP systems. )
1641 Say N if you want to disable CPU hotplug.
1645 prompt "Compat VDSO support"
1646 depends on X86_32 || IA32_EMULATION
1648 Map the 32-bit VDSO to the predictable old-style address too.
1650 Say N here if you are running a sufficiently recent glibc
1651 version (2.3.3 or later), to remove the high-mapped
1652 VDSO mapping and to exclusively use the randomized VDSO.
1657 bool "Built-in kernel command line"
1659 Allow for specifying boot arguments to the kernel at
1660 build time. On some systems (e.g. embedded ones), it is
1661 necessary or convenient to provide some or all of the
1662 kernel boot arguments with the kernel itself (that is,
1663 to not rely on the boot loader to provide them.)
1665 To compile command line arguments into the kernel,
1666 set this option to 'Y', then fill in the
1667 the boot arguments in CONFIG_CMDLINE.
1669 Systems with fully functional boot loaders (i.e. non-embedded)
1670 should leave this option set to 'N'.
1673 string "Built-in kernel command string"
1674 depends on CMDLINE_BOOL
1677 Enter arguments here that should be compiled into the kernel
1678 image and used at boot time. If the boot loader provides a
1679 command line at boot time, it is appended to this string to
1680 form the full kernel command line, when the system boots.
1682 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1683 change this behavior.
1685 In most cases, the command line (whether built-in or provided
1686 by the boot loader) should specify the device for the root
1689 config CMDLINE_OVERRIDE
1690 bool "Built-in command line overrides boot loader arguments"
1691 depends on CMDLINE_BOOL
1693 Set this option to 'Y' to have the kernel ignore the boot loader
1694 command line, and use ONLY the built-in command line.
1696 This is used to work around broken boot loaders. This should
1697 be set to 'N' under normal conditions.
1701 config ARCH_ENABLE_MEMORY_HOTPLUG
1703 depends on X86_64 || (X86_32 && HIGHMEM)
1705 config ARCH_ENABLE_MEMORY_HOTREMOVE
1707 depends on MEMORY_HOTPLUG
1709 config HAVE_ARCH_EARLY_PFN_TO_NID
1713 config USE_PERCPU_NUMA_NODE_ID
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"
1731 depends on APM || APM_MODULE
1734 tristate "APM (Advanced Power Management) BIOS support"
1735 depends on X86_32 && PM_SLEEP
1737 APM is a BIOS specification for saving power using several different
1738 techniques. This is mostly useful for battery powered laptops with
1739 APM compliant BIOSes. If you say Y here, the system time will be
1740 reset after a RESUME operation, the /proc/apm device will provide
1741 battery status information, and user-space programs will receive
1742 notification of APM "events" (e.g. battery status change).
1744 If you select "Y" here, you can disable actual use of the APM
1745 BIOS by passing the "apm=off" option to the kernel at boot time.
1747 Note that the APM support is almost completely disabled for
1748 machines with more than one CPU.
1750 In order to use APM, you will need supporting software. For location
1751 and more information, read <file:Documentation/power/pm.txt> and the
1752 Battery Powered Linux mini-HOWTO, available from
1753 <http://www.tldp.org/docs.html#howto>.
1755 This driver does not spin down disk drives (see the hdparm(8)
1756 manpage ("man 8 hdparm") for that), and it doesn't turn off
1757 VESA-compliant "green" monitors.
1759 This driver does not support the TI 4000M TravelMate and the ACER
1760 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1761 desktop machines also don't have compliant BIOSes, and this driver
1762 may cause those machines to panic during the boot phase.
1764 Generally, if you don't have a battery in your machine, there isn't
1765 much point in using this driver and you should say N. If you get
1766 random kernel OOPSes or reboots that don't seem to be related to
1767 anything, try disabling/enabling this option (or disabling/enabling
1770 Some other things you should try when experiencing seemingly random,
1773 1) make sure that you have enough swap space and that it is
1775 2) pass the "no-hlt" option to the kernel
1776 3) switch on floating point emulation in the kernel and pass
1777 the "no387" option to the kernel
1778 4) pass the "floppy=nodma" option to the kernel
1779 5) pass the "mem=4M" option to the kernel (thereby disabling
1780 all but the first 4 MB of RAM)
1781 6) make sure that the CPU is not over clocked.
1782 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1783 8) disable the cache from your BIOS settings
1784 9) install a fan for the video card or exchange video RAM
1785 10) install a better fan for the CPU
1786 11) exchange RAM chips
1787 12) exchange the motherboard.
1789 To compile this driver as a module, choose M here: the
1790 module will be called apm.
1794 config APM_IGNORE_USER_SUSPEND
1795 bool "Ignore USER SUSPEND"
1797 This option will ignore USER SUSPEND requests. On machines with a
1798 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1799 series notebooks, it is necessary to say Y because of a BIOS bug.
1801 config APM_DO_ENABLE
1802 bool "Enable PM at boot time"
1804 Enable APM features at boot time. From page 36 of the APM BIOS
1805 specification: "When disabled, the APM BIOS does not automatically
1806 power manage devices, enter the Standby State, enter the Suspend
1807 State, or take power saving steps in response to CPU Idle calls."
1808 This driver will make CPU Idle calls when Linux is idle (unless this
1809 feature is turned off -- see "Do CPU IDLE calls", below). This
1810 should always save battery power, but more complicated APM features
1811 will be dependent on your BIOS implementation. You may need to turn
1812 this option off if your computer hangs at boot time when using APM
1813 support, or if it beeps continuously instead of suspending. Turn
1814 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1815 T400CDT. This is off by default since most machines do fine without
1819 bool "Make CPU Idle calls when idle"
1821 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1822 On some machines, this can activate improved power savings, such as
1823 a slowed CPU clock rate, when the machine is idle. These idle calls
1824 are made after the idle loop has run for some length of time (e.g.,
1825 333 mS). On some machines, this will cause a hang at boot time or
1826 whenever the CPU becomes idle. (On machines with more than one CPU,
1827 this option does nothing.)
1829 config APM_DISPLAY_BLANK
1830 bool "Enable console blanking using APM"
1832 Enable console blanking using the APM. Some laptops can use this to
1833 turn off the LCD backlight when the screen blanker of the Linux
1834 virtual console blanks the screen. Note that this is only used by
1835 the virtual console screen blanker, and won't turn off the backlight
1836 when using the X Window system. This also doesn't have anything to
1837 do with your VESA-compliant power-saving monitor. Further, this
1838 option doesn't work for all laptops -- it might not turn off your
1839 backlight at all, or it might print a lot of errors to the console,
1840 especially if you are using gpm.
1842 config APM_ALLOW_INTS
1843 bool "Allow interrupts during APM BIOS calls"
1845 Normally we disable external interrupts while we are making calls to
1846 the APM BIOS as a measure to lessen the effects of a badly behaving
1847 BIOS implementation. The BIOS should reenable interrupts if it
1848 needs to. Unfortunately, some BIOSes do not -- especially those in
1849 many of the newer IBM Thinkpads. If you experience hangs when you
1850 suspend, try setting this to Y. Otherwise, say N.
1854 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1856 source "drivers/cpuidle/Kconfig"
1858 source "drivers/idle/Kconfig"
1863 menu "Bus options (PCI etc.)"
1868 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1870 Find out whether you have a PCI motherboard. PCI is the name of a
1871 bus system, i.e. the way the CPU talks to the other stuff inside
1872 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1873 VESA. If you have PCI, say Y, otherwise N.
1876 prompt "PCI access mode"
1877 depends on X86_32 && PCI
1880 On PCI systems, the BIOS can be used to detect the PCI devices and
1881 determine their configuration. However, some old PCI motherboards
1882 have BIOS bugs and may crash if this is done. Also, some embedded
1883 PCI-based systems don't have any BIOS at all. Linux can also try to
1884 detect the PCI hardware directly without using the BIOS.
1886 With this option, you can specify how Linux should detect the
1887 PCI devices. If you choose "BIOS", the BIOS will be used,
1888 if you choose "Direct", the BIOS won't be used, and if you
1889 choose "MMConfig", then PCI Express MMCONFIG will be used.
1890 If you choose "Any", the kernel will try MMCONFIG, then the
1891 direct access method and falls back to the BIOS if that doesn't
1892 work. If unsure, go with the default, which is "Any".
1897 config PCI_GOMMCONFIG
1914 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1916 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1919 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1923 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1927 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1934 bool "Support mmconfig PCI config space access"
1935 depends on X86_64 && PCI && ACPI
1937 config PCI_CNB20LE_QUIRK
1938 bool "Read CNB20LE Host Bridge Windows"
1941 Read the PCI windows out of the CNB20LE host bridge. This allows
1942 PCI hotplug to work on systems with the CNB20LE chipset which do
1946 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1947 depends on PCI_MSI && ACPI && EXPERIMENTAL
1949 DMA remapping (DMAR) devices support enables independent address
1950 translations for Direct Memory Access (DMA) from devices.
1951 These DMA remapping devices are reported via ACPI tables
1952 and include PCI device scope covered by these DMA
1955 config DMAR_DEFAULT_ON
1957 prompt "Enable DMA Remapping Devices by default"
1960 Selecting this option will enable a DMAR device at boot time if
1961 one is found. If this option is not selected, DMAR support can
1962 be enabled by passing intel_iommu=on to the kernel. It is
1963 recommended you say N here while the DMAR code remains
1966 config DMAR_BROKEN_GFX_WA
1967 bool "Workaround broken graphics drivers (going away soon)"
1968 depends on DMAR && BROKEN
1970 Current Graphics drivers tend to use physical address
1971 for DMA and avoid using DMA APIs. Setting this config
1972 option permits the IOMMU driver to set a unity map for
1973 all the OS-visible memory. Hence the driver can continue
1974 to use physical addresses for DMA, at least until this
1975 option is removed in the 2.6.32 kernel.
1977 config DMAR_FLOPPY_WA
1981 Floppy disk drivers are known to bypass DMA API calls
1982 thereby failing to work when IOMMU is enabled. This
1983 workaround will setup a 1:1 mapping for the first
1984 16MiB to make floppy (an ISA device) work.
1987 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1988 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1990 Supports Interrupt remapping for IO-APIC and MSI devices.
1991 To use x2apic mode in the CPU's which support x2APIC enhancements or
1992 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1994 source "drivers/pci/pcie/Kconfig"
1996 source "drivers/pci/Kconfig"
1998 # x86_64 have no ISA slots, but do have ISA-style DMA.
2007 Find out whether you have ISA slots on your motherboard. ISA is the
2008 name of a bus system, i.e. the way the CPU talks to the other stuff
2009 inside your box. Other bus systems are PCI, EISA, MicroChannel
2010 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2011 newer boards don't support it. If you have ISA, say Y, otherwise N.
2017 The Extended Industry Standard Architecture (EISA) bus was
2018 developed as an open alternative to the IBM MicroChannel bus.
2020 The EISA bus provided some of the features of the IBM MicroChannel
2021 bus while maintaining backward compatibility with cards made for
2022 the older ISA bus. The EISA bus saw limited use between 1988 and
2023 1995 when it was made obsolete by the PCI bus.
2025 Say Y here if you are building a kernel for an EISA-based machine.
2029 source "drivers/eisa/Kconfig"
2034 MicroChannel Architecture is found in some IBM PS/2 machines and
2035 laptops. It is a bus system similar to PCI or ISA. See
2036 <file:Documentation/mca.txt> (and especially the web page given
2037 there) before attempting to build an MCA bus kernel.
2039 source "drivers/mca/Kconfig"
2042 tristate "NatSemi SCx200 support"
2044 This provides basic support for National Semiconductor's
2045 (now AMD's) Geode processors. The driver probes for the
2046 PCI-IDs of several on-chip devices, so its a good dependency
2047 for other scx200_* drivers.
2049 If compiled as a module, the driver is named scx200.
2051 config SCx200HR_TIMER
2052 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2056 This driver provides a clocksource built upon the on-chip
2057 27MHz high-resolution timer. Its also a workaround for
2058 NSC Geode SC-1100's buggy TSC, which loses time when the
2059 processor goes idle (as is done by the scheduler). The
2060 other workaround is idle=poll boot option.
2063 bool "One Laptop Per Child support"
2066 Add support for detecting the unique features of the OLPC
2069 config OLPC_OPENFIRMWARE
2070 bool "Support for OLPC's Open Firmware"
2071 depends on !X86_64 && !X86_PAE
2074 This option adds support for the implementation of Open Firmware
2075 that is used on the OLPC XO-1 Children's Machine.
2076 If unsure, say N here.
2082 depends on CPU_SUP_AMD && PCI
2084 source "drivers/pcmcia/Kconfig"
2086 source "drivers/pci/hotplug/Kconfig"
2091 menu "Executable file formats / Emulations"
2093 source "fs/Kconfig.binfmt"
2095 config IA32_EMULATION
2096 bool "IA32 Emulation"
2098 select COMPAT_BINFMT_ELF
2100 Include code to run 32-bit programs under a 64-bit kernel. You should
2101 likely turn this on, unless you're 100% sure that you don't have any
2102 32-bit programs left.
2105 tristate "IA32 a.out support"
2106 depends on IA32_EMULATION
2108 Support old a.out binaries in the 32bit emulation.
2112 depends on IA32_EMULATION
2114 config COMPAT_FOR_U64_ALIGNMENT
2118 config SYSVIPC_COMPAT
2120 depends on COMPAT && SYSVIPC
2125 config HAVE_ATOMIC_IOMAP
2129 source "net/Kconfig"
2131 source "drivers/Kconfig"
2133 source "drivers/firmware/Kconfig"
2137 source "arch/x86/Kconfig.debug"
2139 source "security/Kconfig"
2141 source "crypto/Kconfig"
2143 source "arch/x86/kvm/Kconfig"
2145 source "lib/Kconfig"