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
206 config GENERIC_HARDIRQS_NO__DO_IRQ
209 config GENERIC_IRQ_PROBE
212 config GENERIC_PENDING_IRQ
214 depends on GENERIC_HARDIRQS && SMP
216 config USE_GENERIC_SMP_HELPERS
222 depends on X86_32 && SMP
226 depends on X86_64 && SMP
232 config X86_TRAMPOLINE
234 depends on SMP || (64BIT && ACPI_SLEEP)
236 config X86_32_LAZY_GS
238 depends on X86_32 && !CC_STACKPROTECTOR
240 config ARCH_HWEIGHT_CFLAGS
242 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
243 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
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
464 bool "SGI 320/540 (Visual Workstation)"
465 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
466 depends on X86_32_NON_STANDARD
468 The SGI Visual Workstation series is an IA32-based workstation
469 based on SGI systems chips with some legacy PC hardware attached.
471 Say Y here to create a kernel to run on the SGI 320 or 540.
473 A kernel compiled for the Visual Workstation will run on general
474 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
477 bool "Summit/EXA (IBM x440)"
478 depends on X86_32_NON_STANDARD
480 This option is needed for IBM systems that use the Summit/EXA chipset.
481 In particular, it is needed for the x440.
484 bool "Unisys ES7000 IA32 series"
485 depends on X86_32_NON_STANDARD && X86_BIGSMP
487 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
488 supposed to run on an IA32-based Unisys ES7000 system.
490 config SCHED_OMIT_FRAME_POINTER
492 prompt "Single-depth WCHAN output"
495 Calculate simpler /proc/<PID>/wchan values. If this option
496 is disabled then wchan values will recurse back to the
497 caller function. This provides more accurate wchan values,
498 at the expense of slightly more scheduling overhead.
500 If in doubt, say "Y".
502 menuconfig PARAVIRT_GUEST
503 bool "Paravirtualized guest support"
505 Say Y here to get to see options related to running Linux under
506 various hypervisors. This option alone does not add any kernel code.
508 If you say N, all options in this submenu will be skipped and disabled.
512 source "arch/x86/xen/Kconfig"
515 bool "VMI Guest support (DEPRECATED)"
519 VMI provides a paravirtualized interface to the VMware ESX server
520 (it could be used by other hypervisors in theory too, but is not
521 at the moment), by linking the kernel to a GPL-ed ROM module
522 provided by the hypervisor.
524 As of September 2009, VMware has started a phased retirement
525 of this feature from VMware's products. Please see
526 feature-removal-schedule.txt for details. If you are
527 planning to enable this option, please note that you cannot
528 live migrate a VMI enabled VM to a future VMware product,
529 which doesn't support VMI. So if you expect your kernel to
530 seamlessly migrate to newer VMware products, keep this
534 bool "KVM paravirtualized clock"
536 select PARAVIRT_CLOCK
538 Turning on this option will allow you to run a paravirtualized clock
539 when running over the KVM hypervisor. Instead of relying on a PIT
540 (or probably other) emulation by the underlying device model, the host
541 provides the guest with timing infrastructure such as time of day, and
545 bool "KVM Guest support"
548 This option enables various optimizations for running under the KVM
551 source "arch/x86/lguest/Kconfig"
554 bool "Enable paravirtualization code"
556 This changes the kernel so it can modify itself when it is run
557 under a hypervisor, potentially improving performance significantly
558 over full virtualization. However, when run without a hypervisor
559 the kernel is theoretically slower and slightly larger.
561 config PARAVIRT_SPINLOCKS
562 bool "Paravirtualization layer for spinlocks"
563 depends on PARAVIRT && SMP && EXPERIMENTAL
565 Paravirtualized spinlocks allow a pvops backend to replace the
566 spinlock implementation with something virtualization-friendly
567 (for example, block the virtual CPU rather than spinning).
569 Unfortunately the downside is an up to 5% performance hit on
570 native kernels, with various workloads.
572 If you are unsure how to answer this question, answer N.
574 config PARAVIRT_CLOCK
579 config PARAVIRT_DEBUG
580 bool "paravirt-ops debugging"
581 depends on PARAVIRT && DEBUG_KERNEL
583 Enable to debug paravirt_ops internals. Specifically, BUG if
584 a paravirt_op is missing when it is called.
588 bool "Disable Bootmem code"
590 Use early_res directly instead of bootmem before slab is ready.
591 - allocator (buddy) [generic]
592 - early allocator (bootmem) [generic]
593 - very early allocator (reserve_early*()) [x86]
594 - very very early allocator (early brk model) [x86]
595 So reduce one layer between early allocator to final allocator
601 This option adds a kernel parameter 'memtest', which allows memtest
603 memtest=0, mean disabled; -- default
604 memtest=1, mean do 1 test pattern;
606 memtest=4, mean do 4 test patterns.
607 If you are unsure how to answer this question, answer N.
609 config X86_SUMMIT_NUMA
611 depends on X86_32 && NUMA && X86_32_NON_STANDARD
613 config X86_CYCLONE_TIMER
615 depends on X86_32_NON_STANDARD
617 source "arch/x86/Kconfig.cpu"
621 prompt "HPET Timer Support" if X86_32
623 Use the IA-PC HPET (High Precision Event Timer) to manage
624 time in preference to the PIT and RTC, if a HPET is
626 HPET is the next generation timer replacing legacy 8254s.
627 The HPET provides a stable time base on SMP
628 systems, unlike the TSC, but it is more expensive to access,
629 as it is off-chip. You can find the HPET spec at
630 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
632 You can safely choose Y here. However, HPET will only be
633 activated if the platform and the BIOS support this feature.
634 Otherwise the 8254 will be used for timing services.
636 Choose N to continue using the legacy 8254 timer.
638 config HPET_EMULATE_RTC
640 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
644 prompt "Langwell APB Timer Support" if X86_MRST
646 APB timer is the replacement for 8254, HPET on X86 MID platforms.
647 The APBT provides a stable time base on SMP
648 systems, unlike the TSC, but it is more expensive to access,
649 as it is off-chip. APB timers are always running regardless of CPU
650 C states, they are used as per CPU clockevent device when possible.
652 # Mark as embedded because too many people got it wrong.
653 # The code disables itself when not needed.
656 bool "Enable DMI scanning" if EMBEDDED
658 Enabled scanning of DMI to identify machine quirks. Say Y
659 here unless you have verified that your setup is not
660 affected by entries in the DMI blacklist. Required by PNP
664 bool "GART IOMMU support" if EMBEDDED
667 depends on X86_64 && PCI && K8_NB
669 Support for full DMA access of devices with 32bit memory access only
670 on systems with more than 3GB. This is usually needed for USB,
671 sound, many IDE/SATA chipsets and some other devices.
672 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
673 based hardware IOMMU and a software bounce buffer based IOMMU used
674 on Intel systems and as fallback.
675 The code is only active when needed (enough memory and limited
676 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
680 bool "IBM Calgary IOMMU support"
682 depends on X86_64 && PCI && EXPERIMENTAL
684 Support for hardware IOMMUs in IBM's xSeries x366 and x460
685 systems. Needed to run systems with more than 3GB of memory
686 properly with 32-bit PCI devices that do not support DAC
687 (Double Address Cycle). Calgary also supports bus level
688 isolation, where all DMAs pass through the IOMMU. This
689 prevents them from going anywhere except their intended
690 destination. This catches hard-to-find kernel bugs and
691 mis-behaving drivers and devices that do not use the DMA-API
692 properly to set up their DMA buffers. The IOMMU can be
693 turned off at boot time with the iommu=off parameter.
694 Normally the kernel will make the right choice by itself.
697 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
699 prompt "Should Calgary be enabled by default?"
700 depends on CALGARY_IOMMU
702 Should Calgary be enabled by default? if you choose 'y', Calgary
703 will be used (if it exists). If you choose 'n', Calgary will not be
704 used even if it exists. If you choose 'n' and would like to use
705 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
709 bool "AMD IOMMU support"
712 depends on X86_64 && PCI && ACPI
714 With this option you can enable support for AMD IOMMU hardware in
715 your system. An IOMMU is a hardware component which provides
716 remapping of DMA memory accesses from devices. With an AMD IOMMU you
717 can isolate the the DMA memory of different devices and protect the
718 system from misbehaving device drivers or hardware.
720 You can find out if your system has an AMD IOMMU if you look into
721 your BIOS for an option to enable it or if you have an IVRS ACPI
724 config AMD_IOMMU_STATS
725 bool "Export AMD IOMMU statistics to debugfs"
729 This option enables code in the AMD IOMMU driver to collect various
730 statistics about whats happening in the driver and exports that
731 information to userspace via debugfs.
734 # need this always selected by IOMMU for the VIA workaround
738 Support for software bounce buffers used on x86-64 systems
739 which don't have a hardware IOMMU (e.g. the current generation
740 of Intel's x86-64 CPUs). Using this PCI devices which can only
741 access 32-bits of memory can be used on systems with more than
742 3 GB of memory. If unsure, say Y.
745 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
748 def_bool (AMD_IOMMU || DMAR)
751 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
752 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
753 select CPUMASK_OFFSTACK
755 Configure maximum number of CPUS and NUMA Nodes for this architecture.
759 int "Maximum number of CPUs" if SMP && !MAXSMP
760 range 2 8 if SMP && X86_32 && !X86_BIGSMP
761 range 2 512 if SMP && !MAXSMP
763 default "4096" if MAXSMP
764 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
767 This allows you to specify the maximum number of CPUs which this
768 kernel will support. The maximum supported value is 512 and the
769 minimum value which makes sense is 2.
771 This is purely to save memory - each supported CPU adds
772 approximately eight kilobytes to the kernel image.
775 bool "SMT (Hyperthreading) scheduler support"
778 SMT scheduler support improves the CPU scheduler's decision making
779 when dealing with Intel Pentium 4 chips with HyperThreading at a
780 cost of slightly increased overhead in some places. If unsure say
785 prompt "Multi-core scheduler support"
788 Multi-core scheduler support improves the CPU scheduler's decision
789 making when dealing with multi-core CPU chips at a cost of slightly
790 increased overhead in some places. If unsure say N here.
792 source "kernel/Kconfig.preempt"
795 bool "Local APIC support on uniprocessors"
796 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
798 A local APIC (Advanced Programmable Interrupt Controller) is an
799 integrated interrupt controller in the CPU. If you have a single-CPU
800 system which has a processor with a local APIC, you can say Y here to
801 enable and use it. If you say Y here even though your machine doesn't
802 have a local APIC, then the kernel will still run with no slowdown at
803 all. The local APIC supports CPU-generated self-interrupts (timer,
804 performance counters), and the NMI watchdog which detects hard
808 bool "IO-APIC support on uniprocessors"
809 depends on X86_UP_APIC
811 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
812 SMP-capable replacement for PC-style interrupt controllers. Most
813 SMP systems and many recent uniprocessor systems have one.
815 If you have a single-CPU system with an IO-APIC, you can say Y here
816 to use it. If you say Y here even though your machine doesn't have
817 an IO-APIC, then the kernel will still run with no slowdown at all.
819 config X86_LOCAL_APIC
821 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
825 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
827 config X86_VISWS_APIC
829 depends on X86_32 && X86_VISWS
831 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
832 bool "Reroute for broken boot IRQs"
833 depends on X86_IO_APIC
835 This option enables a workaround that fixes a source of
836 spurious interrupts. This is recommended when threaded
837 interrupt handling is used on systems where the generation of
838 superfluous "boot interrupts" cannot be disabled.
840 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
841 entry in the chipset's IO-APIC is masked (as, e.g. the RT
842 kernel does during interrupt handling). On chipsets where this
843 boot IRQ generation cannot be disabled, this workaround keeps
844 the original IRQ line masked so that only the equivalent "boot
845 IRQ" is delivered to the CPUs. The workaround also tells the
846 kernel to set up the IRQ handler on the boot IRQ line. In this
847 way only one interrupt is delivered to the kernel. Otherwise
848 the spurious second interrupt may cause the kernel to bring
849 down (vital) interrupt lines.
851 Only affects "broken" chipsets. Interrupt sharing may be
852 increased on these systems.
855 bool "Machine Check / overheating reporting"
857 Machine Check support allows the processor to notify the
858 kernel if it detects a problem (e.g. overheating, data corruption).
859 The action the kernel takes depends on the severity of the problem,
860 ranging from warning messages to halting the machine.
864 prompt "Intel MCE features"
865 depends on X86_MCE && X86_LOCAL_APIC
867 Additional support for intel specific MCE features such as
872 prompt "AMD MCE features"
873 depends on X86_MCE && X86_LOCAL_APIC
875 Additional support for AMD specific MCE features such as
876 the DRAM Error Threshold.
878 config X86_ANCIENT_MCE
879 bool "Support for old Pentium 5 / WinChip machine checks"
880 depends on X86_32 && X86_MCE
882 Include support for machine check handling on old Pentium 5 or WinChip
883 systems. These typically need to be enabled explicitely on the command
886 config X86_MCE_THRESHOLD
887 depends on X86_MCE_AMD || X86_MCE_INTEL
890 config X86_MCE_INJECT
892 tristate "Machine check injector support"
894 Provide support for injecting machine checks for testing purposes.
895 If you don't know what a machine check is and you don't do kernel
896 QA it is safe to say n.
898 config X86_THERMAL_VECTOR
900 depends on X86_MCE_INTEL
903 bool "Enable VM86 support" if EMBEDDED
907 This option is required by programs like DOSEMU to run 16-bit legacy
908 code on X86 processors. It also may be needed by software like
909 XFree86 to initialize some video cards via BIOS. Disabling this
910 option saves about 6k.
913 tristate "Toshiba Laptop support"
916 This adds a driver to safely access the System Management Mode of
917 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
918 not work on models with a Phoenix BIOS. The System Management Mode
919 is used to set the BIOS and power saving options on Toshiba portables.
921 For information on utilities to make use of this driver see the
922 Toshiba Linux utilities web site at:
923 <http://www.buzzard.org.uk/toshiba/>.
925 Say Y if you intend to run this kernel on a Toshiba portable.
929 tristate "Dell laptop support"
931 This adds a driver to safely access the System Management Mode
932 of the CPU on the Dell Inspiron 8000. The System Management Mode
933 is used to read cpu temperature and cooling fan status and to
934 control the fans on the I8K portables.
936 This driver has been tested only on the Inspiron 8000 but it may
937 also work with other Dell laptops. You can force loading on other
938 models by passing the parameter `force=1' to the module. Use at
941 For information on utilities to make use of this driver see the
942 I8K Linux utilities web site at:
943 <http://people.debian.org/~dz/i8k/>
945 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
948 config X86_REBOOTFIXUPS
949 bool "Enable X86 board specific fixups for reboot"
952 This enables chipset and/or board specific fixups to be done
953 in order to get reboot to work correctly. This is only needed on
954 some combinations of hardware and BIOS. The symptom, for which
955 this config is intended, is when reboot ends with a stalled/hung
958 Currently, the only fixup is for the Geode machines using
959 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
961 Say Y if you want to enable the fixup. Currently, it's safe to
962 enable this option even if you don't need it.
966 tristate "/dev/cpu/microcode - microcode support"
969 If you say Y here, you will be able to update the microcode on
970 certain Intel and AMD processors. The Intel support is for the
971 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
972 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
973 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
974 You will obviously need the actual microcode binary data itself
975 which is not shipped with the Linux kernel.
977 This option selects the general module only, you need to select
978 at least one vendor specific module as well.
980 To compile this driver as a module, choose M here: the
981 module will be called microcode.
983 config MICROCODE_INTEL
984 bool "Intel microcode patch loading support"
989 This options enables microcode patch loading support for Intel
992 For latest news and information on obtaining all the required
993 Intel ingredients for this driver, check:
994 <http://www.urbanmyth.org/microcode/>.
997 bool "AMD microcode patch loading support"
1001 If you select this option, microcode patch loading support for AMD
1002 processors will be enabled.
1004 config MICROCODE_OLD_INTERFACE
1006 depends on MICROCODE
1009 tristate "/dev/cpu/*/msr - Model-specific register support"
1011 This device gives privileged processes access to the x86
1012 Model-Specific Registers (MSRs). It is a character device with
1013 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1014 MSR accesses are directed to a specific CPU on multi-processor
1018 tristate "/dev/cpu/*/cpuid - CPU information support"
1020 This device gives processes access to the x86 CPUID instruction to
1021 be executed on a specific processor. It is a character device
1022 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1026 prompt "High Memory Support"
1027 default HIGHMEM64G if X86_NUMAQ
1033 depends on !X86_NUMAQ
1035 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1036 However, the address space of 32-bit x86 processors is only 4
1037 Gigabytes large. That means that, if you have a large amount of
1038 physical memory, not all of it can be "permanently mapped" by the
1039 kernel. The physical memory that's not permanently mapped is called
1042 If you are compiling a kernel which will never run on a machine with
1043 more than 1 Gigabyte total physical RAM, answer "off" here (default
1044 choice and suitable for most users). This will result in a "3GB/1GB"
1045 split: 3GB are mapped so that each process sees a 3GB virtual memory
1046 space and the remaining part of the 4GB virtual memory space is used
1047 by the kernel to permanently map as much physical memory as
1050 If the machine has between 1 and 4 Gigabytes physical RAM, then
1053 If more than 4 Gigabytes is used then answer "64GB" here. This
1054 selection turns Intel PAE (Physical Address Extension) mode on.
1055 PAE implements 3-level paging on IA32 processors. PAE is fully
1056 supported by Linux, PAE mode is implemented on all recent Intel
1057 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1058 then the kernel will not boot on CPUs that don't support PAE!
1060 The actual amount of total physical memory will either be
1061 auto detected or can be forced by using a kernel command line option
1062 such as "mem=256M". (Try "man bootparam" or see the documentation of
1063 your boot loader (lilo or loadlin) about how to pass options to the
1064 kernel at boot time.)
1066 If unsure, say "off".
1070 depends on !X86_NUMAQ
1072 Select this if you have a 32-bit processor and between 1 and 4
1073 gigabytes of physical RAM.
1077 depends on !M386 && !M486
1080 Select this if you have a 32-bit processor and more than 4
1081 gigabytes of physical RAM.
1086 depends on EXPERIMENTAL
1087 prompt "Memory split" if EMBEDDED
1091 Select the desired split between kernel and user memory.
1093 If the address range available to the kernel is less than the
1094 physical memory installed, the remaining memory will be available
1095 as "high memory". Accessing high memory is a little more costly
1096 than low memory, as it needs to be mapped into the kernel first.
1097 Note that increasing the kernel address space limits the range
1098 available to user programs, making the address space there
1099 tighter. Selecting anything other than the default 3G/1G split
1100 will also likely make your kernel incompatible with binary-only
1103 If you are not absolutely sure what you are doing, leave this
1107 bool "3G/1G user/kernel split"
1108 config VMSPLIT_3G_OPT
1110 bool "3G/1G user/kernel split (for full 1G low memory)"
1112 bool "2G/2G user/kernel split"
1113 config VMSPLIT_2G_OPT
1115 bool "2G/2G user/kernel split (for full 2G low memory)"
1117 bool "1G/3G user/kernel split"
1122 default 0xB0000000 if VMSPLIT_3G_OPT
1123 default 0x80000000 if VMSPLIT_2G
1124 default 0x78000000 if VMSPLIT_2G_OPT
1125 default 0x40000000 if VMSPLIT_1G
1131 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1134 bool "PAE (Physical Address Extension) Support"
1135 depends on X86_32 && !HIGHMEM4G
1137 PAE is required for NX support, and furthermore enables
1138 larger swapspace support for non-overcommit purposes. It
1139 has the cost of more pagetable lookup overhead, and also
1140 consumes more pagetable space per process.
1142 config ARCH_PHYS_ADDR_T_64BIT
1143 def_bool X86_64 || X86_PAE
1145 config DIRECT_GBPAGES
1146 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1150 Allow the kernel linear mapping to use 1GB pages on CPUs that
1151 support it. This can improve the kernel's performance a tiny bit by
1152 reducing TLB pressure. If in doubt, say "Y".
1154 # Common NUMA Features
1156 bool "Numa Memory Allocation and Scheduler Support"
1158 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1159 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1161 Enable NUMA (Non Uniform Memory Access) support.
1163 The kernel will try to allocate memory used by a CPU on the
1164 local memory controller of the CPU and add some more
1165 NUMA awareness to the kernel.
1167 For 64-bit this is recommended if the system is Intel Core i7
1168 (or later), AMD Opteron, or EM64T NUMA.
1170 For 32-bit this is only needed on (rare) 32-bit-only platforms
1171 that support NUMA topologies, such as NUMAQ / Summit, or if you
1172 boot a 32-bit kernel on a 64-bit NUMA platform.
1174 Otherwise, you should say N.
1176 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1177 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1181 prompt "Old style AMD Opteron NUMA detection"
1182 depends on X86_64 && NUMA && PCI
1184 Enable K8 NUMA node topology detection. You should say Y here if
1185 you have a multi processor AMD K8 system. This uses an old
1186 method to read the NUMA configuration directly from the builtin
1187 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1188 instead, which also takes priority if both are compiled in.
1190 config X86_64_ACPI_NUMA
1192 prompt "ACPI NUMA detection"
1193 depends on X86_64 && NUMA && ACPI && PCI
1196 Enable ACPI SRAT based node topology detection.
1198 # Some NUMA nodes have memory ranges that span
1199 # other nodes. Even though a pfn is valid and
1200 # between a node's start and end pfns, it may not
1201 # reside on that node. See memmap_init_zone()
1203 config NODES_SPAN_OTHER_NODES
1205 depends on X86_64_ACPI_NUMA
1208 bool "NUMA emulation"
1209 depends on X86_64 && NUMA
1211 Enable NUMA emulation. A flat machine will be split
1212 into virtual nodes when booted with "numa=fake=N", where N is the
1213 number of nodes. This is only useful for debugging.
1216 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1218 default "10" if MAXSMP
1219 default "6" if X86_64
1220 default "4" if X86_NUMAQ
1222 depends on NEED_MULTIPLE_NODES
1224 Specify the maximum number of NUMA Nodes available on the target
1225 system. Increases memory reserved to accommodate various tables.
1227 config HAVE_ARCH_BOOTMEM
1229 depends on X86_32 && NUMA
1231 config ARCH_HAVE_MEMORY_PRESENT
1233 depends on X86_32 && DISCONTIGMEM
1235 config NEED_NODE_MEMMAP_SIZE
1237 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1239 config HAVE_ARCH_ALLOC_REMAP
1241 depends on X86_32 && NUMA
1243 config ARCH_FLATMEM_ENABLE
1245 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1247 config ARCH_DISCONTIGMEM_ENABLE
1249 depends on NUMA && X86_32
1251 config ARCH_DISCONTIGMEM_DEFAULT
1253 depends on NUMA && X86_32
1255 config ARCH_PROC_KCORE_TEXT
1257 depends on X86_64 && PROC_KCORE
1259 config ARCH_SPARSEMEM_DEFAULT
1263 config ARCH_SPARSEMEM_ENABLE
1265 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1266 select SPARSEMEM_STATIC if X86_32
1267 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1269 config ARCH_SELECT_MEMORY_MODEL
1271 depends on ARCH_SPARSEMEM_ENABLE
1273 config ARCH_MEMORY_PROBE
1275 depends on MEMORY_HOTPLUG
1277 config ILLEGAL_POINTER_VALUE
1280 default 0xdead000000000000 if X86_64
1285 bool "Allocate 3rd-level pagetables from highmem"
1288 The VM uses one page table entry for each page of physical memory.
1289 For systems with a lot of RAM, this can be wasteful of precious
1290 low memory. Setting this option will put user-space page table
1291 entries in high memory.
1293 config X86_CHECK_BIOS_CORRUPTION
1294 bool "Check for low memory corruption"
1296 Periodically check for memory corruption in low memory, which
1297 is suspected to be caused by BIOS. Even when enabled in the
1298 configuration, it is disabled at runtime. Enable it by
1299 setting "memory_corruption_check=1" on the kernel command
1300 line. By default it scans the low 64k of memory every 60
1301 seconds; see the memory_corruption_check_size and
1302 memory_corruption_check_period parameters in
1303 Documentation/kernel-parameters.txt to adjust this.
1305 When enabled with the default parameters, this option has
1306 almost no overhead, as it reserves a relatively small amount
1307 of memory and scans it infrequently. It both detects corruption
1308 and prevents it from affecting the running system.
1310 It is, however, intended as a diagnostic tool; if repeatable
1311 BIOS-originated corruption always affects the same memory,
1312 you can use memmap= to prevent the kernel from using that
1315 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1316 bool "Set the default setting of memory_corruption_check"
1317 depends on X86_CHECK_BIOS_CORRUPTION
1320 Set whether the default state of memory_corruption_check is
1323 config X86_RESERVE_LOW_64K
1324 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1327 Reserve the first 64K of physical RAM on BIOSes that are known
1328 to potentially corrupt that memory range. A numbers of BIOSes are
1329 known to utilize this area during suspend/resume, so it must not
1330 be used by the kernel.
1332 Set this to N if you are absolutely sure that you trust the BIOS
1333 to get all its memory reservations and usages right.
1335 If you have doubts about the BIOS (e.g. suspend/resume does not
1336 work or there's kernel crashes after certain hardware hotplug
1337 events) and it's not AMI or Phoenix, then you might want to enable
1338 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1339 corruption patterns.
1343 config MATH_EMULATION
1345 prompt "Math emulation" if X86_32
1347 Linux can emulate a math coprocessor (used for floating point
1348 operations) if you don't have one. 486DX and Pentium processors have
1349 a math coprocessor built in, 486SX and 386 do not, unless you added
1350 a 487DX or 387, respectively. (The messages during boot time can
1351 give you some hints here ["man dmesg"].) Everyone needs either a
1352 coprocessor or this emulation.
1354 If you don't have a math coprocessor, you need to say Y here; if you
1355 say Y here even though you have a coprocessor, the coprocessor will
1356 be used nevertheless. (This behavior can be changed with the kernel
1357 command line option "no387", which comes handy if your coprocessor
1358 is broken. Try "man bootparam" or see the documentation of your boot
1359 loader (lilo or loadlin) about how to pass options to the kernel at
1360 boot time.) This means that it is a good idea to say Y here if you
1361 intend to use this kernel on different machines.
1363 More information about the internals of the Linux math coprocessor
1364 emulation can be found in <file:arch/x86/math-emu/README>.
1366 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1367 kernel, it won't hurt.
1371 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1373 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1374 the Memory Type Range Registers (MTRRs) may be used to control
1375 processor access to memory ranges. This is most useful if you have
1376 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1377 allows bus write transfers to be combined into a larger transfer
1378 before bursting over the PCI/AGP bus. This can increase performance
1379 of image write operations 2.5 times or more. Saying Y here creates a
1380 /proc/mtrr file which may be used to manipulate your processor's
1381 MTRRs. Typically the X server should use this.
1383 This code has a reasonably generic interface so that similar
1384 control registers on other processors can be easily supported
1387 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1388 Registers (ARRs) which provide a similar functionality to MTRRs. For
1389 these, the ARRs are used to emulate the MTRRs.
1390 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1391 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1392 write-combining. All of these processors are supported by this code
1393 and it makes sense to say Y here if you have one of them.
1395 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1396 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1397 can lead to all sorts of problems, so it's good to say Y here.
1399 You can safely say Y even if your machine doesn't have MTRRs, you'll
1400 just add about 9 KB to your kernel.
1402 See <file:Documentation/x86/mtrr.txt> for more information.
1404 config MTRR_SANITIZER
1406 prompt "MTRR cleanup support"
1409 Convert MTRR layout from continuous to discrete, so X drivers can
1410 add writeback entries.
1412 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1413 The largest mtrr entry size for a continuous block can be set with
1418 config MTRR_SANITIZER_ENABLE_DEFAULT
1419 int "MTRR cleanup enable value (0-1)"
1422 depends on MTRR_SANITIZER
1424 Enable mtrr cleanup default value
1426 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1427 int "MTRR cleanup spare reg num (0-7)"
1430 depends on MTRR_SANITIZER
1432 mtrr cleanup spare entries default, it can be changed via
1433 mtrr_spare_reg_nr=N on the kernel command line.
1437 prompt "x86 PAT support" if EMBEDDED
1440 Use PAT attributes to setup page level cache control.
1442 PATs are the modern equivalents of MTRRs and are much more
1443 flexible than MTRRs.
1445 Say N here if you see bootup problems (boot crash, boot hang,
1446 spontaneous reboots) or a non-working video driver.
1450 config ARCH_USES_PG_UNCACHED
1455 bool "EFI runtime service support"
1458 This enables the kernel to use EFI runtime services that are
1459 available (such as the EFI variable services).
1461 This option is only useful on systems that have EFI firmware.
1462 In addition, you should use the latest ELILO loader available
1463 at <http://elilo.sourceforge.net> in order to take advantage
1464 of EFI runtime services. However, even with this option, the
1465 resultant kernel should continue to boot on existing non-EFI
1470 prompt "Enable seccomp to safely compute untrusted bytecode"
1472 This kernel feature is useful for number crunching applications
1473 that may need to compute untrusted bytecode during their
1474 execution. By using pipes or other transports made available to
1475 the process as file descriptors supporting the read/write
1476 syscalls, it's possible to isolate those applications in
1477 their own address space using seccomp. Once seccomp is
1478 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1479 and the task is only allowed to execute a few safe syscalls
1480 defined by each seccomp mode.
1482 If unsure, say Y. Only embedded should say N here.
1484 config CC_STACKPROTECTOR
1485 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1487 This option turns on the -fstack-protector GCC feature. This
1488 feature puts, at the beginning of functions, a canary value on
1489 the stack just before the return address, and validates
1490 the value just before actually returning. Stack based buffer
1491 overflows (that need to overwrite this return address) now also
1492 overwrite the canary, which gets detected and the attack is then
1493 neutralized via a kernel panic.
1495 This feature requires gcc version 4.2 or above, or a distribution
1496 gcc with the feature backported. Older versions are automatically
1497 detected and for those versions, this configuration option is
1498 ignored. (and a warning is printed during bootup)
1500 source kernel/Kconfig.hz
1503 bool "kexec system call"
1505 kexec is a system call that implements the ability to shutdown your
1506 current kernel, and to start another kernel. It is like a reboot
1507 but it is independent of the system firmware. And like a reboot
1508 you can start any kernel with it, not just Linux.
1510 The name comes from the similarity to the exec system call.
1512 It is an ongoing process to be certain the hardware in a machine
1513 is properly shutdown, so do not be surprised if this code does not
1514 initially work for you. It may help to enable device hotplugging
1515 support. As of this writing the exact hardware interface is
1516 strongly in flux, so no good recommendation can be made.
1519 bool "kernel crash dumps"
1520 depends on X86_64 || (X86_32 && HIGHMEM)
1522 Generate crash dump after being started by kexec.
1523 This should be normally only set in special crash dump kernels
1524 which are loaded in the main kernel with kexec-tools into
1525 a specially reserved region and then later executed after
1526 a crash by kdump/kexec. The crash dump kernel must be compiled
1527 to a memory address not used by the main kernel or BIOS using
1528 PHYSICAL_START, or it must be built as a relocatable image
1529 (CONFIG_RELOCATABLE=y).
1530 For more details see Documentation/kdump/kdump.txt
1533 bool "kexec jump (EXPERIMENTAL)"
1534 depends on EXPERIMENTAL
1535 depends on KEXEC && HIBERNATION
1537 Jump between original kernel and kexeced kernel and invoke
1538 code in physical address mode via KEXEC
1540 config PHYSICAL_START
1541 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1544 This gives the physical address where the kernel is loaded.
1546 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1547 bzImage will decompress itself to above physical address and
1548 run from there. Otherwise, bzImage will run from the address where
1549 it has been loaded by the boot loader and will ignore above physical
1552 In normal kdump cases one does not have to set/change this option
1553 as now bzImage can be compiled as a completely relocatable image
1554 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1555 address. This option is mainly useful for the folks who don't want
1556 to use a bzImage for capturing the crash dump and want to use a
1557 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1558 to be specifically compiled to run from a specific memory area
1559 (normally a reserved region) and this option comes handy.
1561 So if you are using bzImage for capturing the crash dump,
1562 leave the value here unchanged to 0x1000000 and set
1563 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1564 for capturing the crash dump change this value to start of
1565 the reserved region. In other words, it can be set based on
1566 the "X" value as specified in the "crashkernel=YM@XM"
1567 command line boot parameter passed to the panic-ed
1568 kernel. Please take a look at Documentation/kdump/kdump.txt
1569 for more details about crash dumps.
1571 Usage of bzImage for capturing the crash dump is recommended as
1572 one does not have to build two kernels. Same kernel can be used
1573 as production kernel and capture kernel. Above option should have
1574 gone away after relocatable bzImage support is introduced. But it
1575 is present because there are users out there who continue to use
1576 vmlinux for dump capture. This option should go away down the
1579 Don't change this unless you know what you are doing.
1582 bool "Build a relocatable kernel"
1585 This builds a kernel image that retains relocation information
1586 so it can be loaded someplace besides the default 1MB.
1587 The relocations tend to make the kernel binary about 10% larger,
1588 but are discarded at runtime.
1590 One use is for the kexec on panic case where the recovery kernel
1591 must live at a different physical address than the primary
1594 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1595 it has been loaded at and the compile time physical address
1596 (CONFIG_PHYSICAL_START) is ignored.
1598 # Relocation on x86-32 needs some additional build support
1599 config X86_NEED_RELOCS
1601 depends on X86_32 && RELOCATABLE
1603 config PHYSICAL_ALIGN
1604 hex "Alignment value to which kernel should be aligned" if X86_32
1606 range 0x2000 0x1000000
1608 This value puts the alignment restrictions on physical address
1609 where kernel is loaded and run from. Kernel is compiled for an
1610 address which meets above alignment restriction.
1612 If bootloader loads the kernel at a non-aligned address and
1613 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1614 address aligned to above value and run from there.
1616 If bootloader loads the kernel at a non-aligned address and
1617 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1618 load address and decompress itself to the address it has been
1619 compiled for and run from there. The address for which kernel is
1620 compiled already meets above alignment restrictions. Hence the
1621 end result is that kernel runs from a physical address meeting
1622 above alignment restrictions.
1624 Don't change this unless you know what you are doing.
1627 bool "Support for hot-pluggable CPUs"
1628 depends on SMP && HOTPLUG
1630 Say Y here to allow turning CPUs off and on. CPUs can be
1631 controlled through /sys/devices/system/cpu.
1632 ( Note: power management support will enable this option
1633 automatically on SMP systems. )
1634 Say N if you want to disable CPU hotplug.
1638 prompt "Compat VDSO support"
1639 depends on X86_32 || IA32_EMULATION
1641 Map the 32-bit VDSO to the predictable old-style address too.
1643 Say N here if you are running a sufficiently recent glibc
1644 version (2.3.3 or later), to remove the high-mapped
1645 VDSO mapping and to exclusively use the randomized VDSO.
1650 bool "Built-in kernel command line"
1652 Allow for specifying boot arguments to the kernel at
1653 build time. On some systems (e.g. embedded ones), it is
1654 necessary or convenient to provide some or all of the
1655 kernel boot arguments with the kernel itself (that is,
1656 to not rely on the boot loader to provide them.)
1658 To compile command line arguments into the kernel,
1659 set this option to 'Y', then fill in the
1660 the boot arguments in CONFIG_CMDLINE.
1662 Systems with fully functional boot loaders (i.e. non-embedded)
1663 should leave this option set to 'N'.
1666 string "Built-in kernel command string"
1667 depends on CMDLINE_BOOL
1670 Enter arguments here that should be compiled into the kernel
1671 image and used at boot time. If the boot loader provides a
1672 command line at boot time, it is appended to this string to
1673 form the full kernel command line, when the system boots.
1675 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1676 change this behavior.
1678 In most cases, the command line (whether built-in or provided
1679 by the boot loader) should specify the device for the root
1682 config CMDLINE_OVERRIDE
1683 bool "Built-in command line overrides boot loader arguments"
1684 depends on CMDLINE_BOOL
1686 Set this option to 'Y' to have the kernel ignore the boot loader
1687 command line, and use ONLY the built-in command line.
1689 This is used to work around broken boot loaders. This should
1690 be set to 'N' under normal conditions.
1694 config ARCH_ENABLE_MEMORY_HOTPLUG
1696 depends on X86_64 || (X86_32 && HIGHMEM)
1698 config ARCH_ENABLE_MEMORY_HOTREMOVE
1700 depends on MEMORY_HOTPLUG
1702 config HAVE_ARCH_EARLY_PFN_TO_NID
1706 menu "Power management and ACPI options"
1708 config ARCH_HIBERNATION_HEADER
1710 depends on X86_64 && HIBERNATION
1712 source "kernel/power/Kconfig"
1714 source "drivers/acpi/Kconfig"
1716 source "drivers/sfi/Kconfig"
1720 depends on APM || APM_MODULE
1723 tristate "APM (Advanced Power Management) BIOS support"
1724 depends on X86_32 && PM_SLEEP
1726 APM is a BIOS specification for saving power using several different
1727 techniques. This is mostly useful for battery powered laptops with
1728 APM compliant BIOSes. If you say Y here, the system time will be
1729 reset after a RESUME operation, the /proc/apm device will provide
1730 battery status information, and user-space programs will receive
1731 notification of APM "events" (e.g. battery status change).
1733 If you select "Y" here, you can disable actual use of the APM
1734 BIOS by passing the "apm=off" option to the kernel at boot time.
1736 Note that the APM support is almost completely disabled for
1737 machines with more than one CPU.
1739 In order to use APM, you will need supporting software. For location
1740 and more information, read <file:Documentation/power/pm.txt> and the
1741 Battery Powered Linux mini-HOWTO, available from
1742 <http://www.tldp.org/docs.html#howto>.
1744 This driver does not spin down disk drives (see the hdparm(8)
1745 manpage ("man 8 hdparm") for that), and it doesn't turn off
1746 VESA-compliant "green" monitors.
1748 This driver does not support the TI 4000M TravelMate and the ACER
1749 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1750 desktop machines also don't have compliant BIOSes, and this driver
1751 may cause those machines to panic during the boot phase.
1753 Generally, if you don't have a battery in your machine, there isn't
1754 much point in using this driver and you should say N. If you get
1755 random kernel OOPSes or reboots that don't seem to be related to
1756 anything, try disabling/enabling this option (or disabling/enabling
1759 Some other things you should try when experiencing seemingly random,
1762 1) make sure that you have enough swap space and that it is
1764 2) pass the "no-hlt" option to the kernel
1765 3) switch on floating point emulation in the kernel and pass
1766 the "no387" option to the kernel
1767 4) pass the "floppy=nodma" option to the kernel
1768 5) pass the "mem=4M" option to the kernel (thereby disabling
1769 all but the first 4 MB of RAM)
1770 6) make sure that the CPU is not over clocked.
1771 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1772 8) disable the cache from your BIOS settings
1773 9) install a fan for the video card or exchange video RAM
1774 10) install a better fan for the CPU
1775 11) exchange RAM chips
1776 12) exchange the motherboard.
1778 To compile this driver as a module, choose M here: the
1779 module will be called apm.
1783 config APM_IGNORE_USER_SUSPEND
1784 bool "Ignore USER SUSPEND"
1786 This option will ignore USER SUSPEND requests. On machines with a
1787 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1788 series notebooks, it is necessary to say Y because of a BIOS bug.
1790 config APM_DO_ENABLE
1791 bool "Enable PM at boot time"
1793 Enable APM features at boot time. From page 36 of the APM BIOS
1794 specification: "When disabled, the APM BIOS does not automatically
1795 power manage devices, enter the Standby State, enter the Suspend
1796 State, or take power saving steps in response to CPU Idle calls."
1797 This driver will make CPU Idle calls when Linux is idle (unless this
1798 feature is turned off -- see "Do CPU IDLE calls", below). This
1799 should always save battery power, but more complicated APM features
1800 will be dependent on your BIOS implementation. You may need to turn
1801 this option off if your computer hangs at boot time when using APM
1802 support, or if it beeps continuously instead of suspending. Turn
1803 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1804 T400CDT. This is off by default since most machines do fine without
1808 bool "Make CPU Idle calls when idle"
1810 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1811 On some machines, this can activate improved power savings, such as
1812 a slowed CPU clock rate, when the machine is idle. These idle calls
1813 are made after the idle loop has run for some length of time (e.g.,
1814 333 mS). On some machines, this will cause a hang at boot time or
1815 whenever the CPU becomes idle. (On machines with more than one CPU,
1816 this option does nothing.)
1818 config APM_DISPLAY_BLANK
1819 bool "Enable console blanking using APM"
1821 Enable console blanking using the APM. Some laptops can use this to
1822 turn off the LCD backlight when the screen blanker of the Linux
1823 virtual console blanks the screen. Note that this is only used by
1824 the virtual console screen blanker, and won't turn off the backlight
1825 when using the X Window system. This also doesn't have anything to
1826 do with your VESA-compliant power-saving monitor. Further, this
1827 option doesn't work for all laptops -- it might not turn off your
1828 backlight at all, or it might print a lot of errors to the console,
1829 especially if you are using gpm.
1831 config APM_ALLOW_INTS
1832 bool "Allow interrupts during APM BIOS calls"
1834 Normally we disable external interrupts while we are making calls to
1835 the APM BIOS as a measure to lessen the effects of a badly behaving
1836 BIOS implementation. The BIOS should reenable interrupts if it
1837 needs to. Unfortunately, some BIOSes do not -- especially those in
1838 many of the newer IBM Thinkpads. If you experience hangs when you
1839 suspend, try setting this to Y. Otherwise, say N.
1843 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1845 source "drivers/cpuidle/Kconfig"
1847 source "drivers/idle/Kconfig"
1852 menu "Bus options (PCI etc.)"
1857 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1859 Find out whether you have a PCI motherboard. PCI is the name of a
1860 bus system, i.e. the way the CPU talks to the other stuff inside
1861 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1862 VESA. If you have PCI, say Y, otherwise N.
1865 prompt "PCI access mode"
1866 depends on X86_32 && PCI
1869 On PCI systems, the BIOS can be used to detect the PCI devices and
1870 determine their configuration. However, some old PCI motherboards
1871 have BIOS bugs and may crash if this is done. Also, some embedded
1872 PCI-based systems don't have any BIOS at all. Linux can also try to
1873 detect the PCI hardware directly without using the BIOS.
1875 With this option, you can specify how Linux should detect the
1876 PCI devices. If you choose "BIOS", the BIOS will be used,
1877 if you choose "Direct", the BIOS won't be used, and if you
1878 choose "MMConfig", then PCI Express MMCONFIG will be used.
1879 If you choose "Any", the kernel will try MMCONFIG, then the
1880 direct access method and falls back to the BIOS if that doesn't
1881 work. If unsure, go with the default, which is "Any".
1886 config PCI_GOMMCONFIG
1903 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1905 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1908 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1912 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1916 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1923 bool "Support mmconfig PCI config space access"
1924 depends on X86_64 && PCI && ACPI
1926 config PCI_CNB20LE_QUIRK
1927 bool "Read CNB20LE Host Bridge Windows"
1930 Read the PCI windows out of the CNB20LE host bridge. This allows
1931 PCI hotplug to work on systems with the CNB20LE chipset which do
1935 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1936 depends on PCI_MSI && ACPI && EXPERIMENTAL
1938 DMA remapping (DMAR) devices support enables independent address
1939 translations for Direct Memory Access (DMA) from devices.
1940 These DMA remapping devices are reported via ACPI tables
1941 and include PCI device scope covered by these DMA
1944 config DMAR_DEFAULT_ON
1946 prompt "Enable DMA Remapping Devices by default"
1949 Selecting this option will enable a DMAR device at boot time if
1950 one is found. If this option is not selected, DMAR support can
1951 be enabled by passing intel_iommu=on to the kernel. It is
1952 recommended you say N here while the DMAR code remains
1955 config DMAR_BROKEN_GFX_WA
1956 bool "Workaround broken graphics drivers (going away soon)"
1957 depends on DMAR && BROKEN
1959 Current Graphics drivers tend to use physical address
1960 for DMA and avoid using DMA APIs. Setting this config
1961 option permits the IOMMU driver to set a unity map for
1962 all the OS-visible memory. Hence the driver can continue
1963 to use physical addresses for DMA, at least until this
1964 option is removed in the 2.6.32 kernel.
1966 config DMAR_FLOPPY_WA
1970 Floppy disk drivers are known to bypass DMA API calls
1971 thereby failing to work when IOMMU is enabled. This
1972 workaround will setup a 1:1 mapping for the first
1973 16MiB to make floppy (an ISA device) work.
1976 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1977 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1979 Supports Interrupt remapping for IO-APIC and MSI devices.
1980 To use x2apic mode in the CPU's which support x2APIC enhancements or
1981 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1983 source "drivers/pci/pcie/Kconfig"
1985 source "drivers/pci/Kconfig"
1987 # x86_64 have no ISA slots, but do have ISA-style DMA.
1996 Find out whether you have ISA slots on your motherboard. ISA is the
1997 name of a bus system, i.e. the way the CPU talks to the other stuff
1998 inside your box. Other bus systems are PCI, EISA, MicroChannel
1999 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2000 newer boards don't support it. If you have ISA, say Y, otherwise N.
2006 The Extended Industry Standard Architecture (EISA) bus was
2007 developed as an open alternative to the IBM MicroChannel bus.
2009 The EISA bus provided some of the features of the IBM MicroChannel
2010 bus while maintaining backward compatibility with cards made for
2011 the older ISA bus. The EISA bus saw limited use between 1988 and
2012 1995 when it was made obsolete by the PCI bus.
2014 Say Y here if you are building a kernel for an EISA-based machine.
2018 source "drivers/eisa/Kconfig"
2023 MicroChannel Architecture is found in some IBM PS/2 machines and
2024 laptops. It is a bus system similar to PCI or ISA. See
2025 <file:Documentation/mca.txt> (and especially the web page given
2026 there) before attempting to build an MCA bus kernel.
2028 source "drivers/mca/Kconfig"
2031 tristate "NatSemi SCx200 support"
2033 This provides basic support for National Semiconductor's
2034 (now AMD's) Geode processors. The driver probes for the
2035 PCI-IDs of several on-chip devices, so its a good dependency
2036 for other scx200_* drivers.
2038 If compiled as a module, the driver is named scx200.
2040 config SCx200HR_TIMER
2041 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2042 depends on SCx200 && GENERIC_TIME
2045 This driver provides a clocksource built upon the on-chip
2046 27MHz high-resolution timer. Its also a workaround for
2047 NSC Geode SC-1100's buggy TSC, which loses time when the
2048 processor goes idle (as is done by the scheduler). The
2049 other workaround is idle=poll boot option.
2052 bool "One Laptop Per Child support"
2055 Add support for detecting the unique features of the OLPC
2062 depends on CPU_SUP_AMD && PCI
2064 source "drivers/pcmcia/Kconfig"
2066 source "drivers/pci/hotplug/Kconfig"
2071 menu "Executable file formats / Emulations"
2073 source "fs/Kconfig.binfmt"
2075 config IA32_EMULATION
2076 bool "IA32 Emulation"
2078 select COMPAT_BINFMT_ELF
2080 Include code to run 32-bit programs under a 64-bit kernel. You should
2081 likely turn this on, unless you're 100% sure that you don't have any
2082 32-bit programs left.
2085 tristate "IA32 a.out support"
2086 depends on IA32_EMULATION
2088 Support old a.out binaries in the 32bit emulation.
2092 depends on IA32_EMULATION
2094 config COMPAT_FOR_U64_ALIGNMENT
2098 config SYSVIPC_COMPAT
2100 depends on COMPAT && SYSVIPC
2105 config HAVE_ATOMIC_IOMAP
2109 source "net/Kconfig"
2111 source "drivers/Kconfig"
2113 source "drivers/firmware/Kconfig"
2117 source "arch/x86/Kconfig.debug"
2119 source "security/Kconfig"
2121 source "crypto/Kconfig"
2123 source "arch/x86/kvm/Kconfig"
2125 source "lib/Kconfig"