3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
17 select X86_DEV_DMA_OPS
22 select HAVE_AOUT if X86_32
23 select HAVE_UNSTABLE_SCHED_CLOCK
26 select HAVE_PCSPKR_PLATFORM
27 select HAVE_PERF_EVENTS
29 select HAVE_IOREMAP_PROT
32 select HAVE_MEMBLOCK_NODE_MAP
33 select ARCH_DISCARD_MEMBLOCK
34 select ARCH_WANT_OPTIONAL_GPIOLIB
35 select ARCH_WANT_FRAME_POINTERS
37 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
38 select HAVE_KRETPROBES
40 select HAVE_FTRACE_MCOUNT_RECORD
41 select HAVE_FENTRY if X86_64
42 select HAVE_C_RECORDMCOUNT
43 select HAVE_DYNAMIC_FTRACE
44 select HAVE_FUNCTION_TRACER
45 select HAVE_FUNCTION_GRAPH_TRACER
46 select HAVE_FUNCTION_GRAPH_FP_TEST
47 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
48 select HAVE_SYSCALL_TRACEPOINTS
51 select HAVE_ARCH_TRACEHOOK
52 select HAVE_GENERIC_DMA_COHERENT if X86_32
53 select HAVE_EFFICIENT_UNALIGNED_ACCESS
54 select USER_STACKTRACE_SUPPORT
55 select HAVE_REGS_AND_STACK_ACCESS_API
56 select HAVE_DMA_API_DEBUG
57 select HAVE_KERNEL_GZIP
58 select HAVE_KERNEL_BZIP2
59 select HAVE_KERNEL_LZMA
61 select HAVE_KERNEL_LZO
62 select HAVE_HW_BREAKPOINT
63 select HAVE_MIXED_BREAKPOINTS_REGS
65 select HAVE_PERF_EVENTS_NMI
67 select HAVE_PERF_USER_STACK_DUMP
69 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
70 select HAVE_CMPXCHG_LOCAL if !M386
71 select HAVE_CMPXCHG_DOUBLE
72 select HAVE_ARCH_KMEMCHECK
73 select HAVE_USER_RETURN_NOTIFIER
74 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
75 select HAVE_ARCH_JUMP_LABEL
76 select HAVE_TEXT_POKE_SMP
77 select HAVE_GENERIC_HARDIRQS
78 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
80 select GENERIC_FIND_FIRST_BIT
81 select GENERIC_IRQ_PROBE
82 select GENERIC_PENDING_IRQ if SMP
83 select GENERIC_IRQ_SHOW
84 select GENERIC_CLOCKEVENTS_MIN_ADJUST
85 select IRQ_FORCED_THREADING
86 select USE_GENERIC_SMP_HELPERS if SMP
87 select HAVE_BPF_JIT if X86_64
89 select ARCH_HAVE_NMI_SAFE_CMPXCHG
91 select DCACHE_WORD_ACCESS
92 select GENERIC_SMP_IDLE_THREAD
93 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
94 select HAVE_ARCH_SECCOMP_FILTER
95 select BUILDTIME_EXTABLE_SORT
96 select GENERIC_CMOS_UPDATE
97 select CLOCKSOURCE_WATCHDOG
98 select GENERIC_CLOCKEVENTS
99 select ARCH_CLOCKSOURCE_DATA if X86_64
100 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
101 select GENERIC_TIME_VSYSCALL if X86_64
102 select KTIME_SCALAR if X86_32
103 select GENERIC_STRNCPY_FROM_USER
104 select GENERIC_STRNLEN_USER
105 select MODULES_USE_ELF_REL if X86_32
106 select MODULES_USE_ELF_RELA if X86_64
107 select HAVE_RCU_USER_QS if X86_64
108 select HAVE_IRQ_TIME_ACCOUNTING
109 select GENERIC_KERNEL_THREAD
111 config INSTRUCTION_DECODER
113 depends on KPROBES || PERF_EVENTS || UPROBES
117 default "elf32-i386" if X86_32
118 default "elf64-x86-64" if X86_64
120 config ARCH_DEFCONFIG
122 default "arch/x86/configs/i386_defconfig" if X86_32
123 default "arch/x86/configs/x86_64_defconfig" if X86_64
125 config LOCKDEP_SUPPORT
128 config STACKTRACE_SUPPORT
131 config HAVE_LATENCYTOP_SUPPORT
140 config NEED_DMA_MAP_STATE
142 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
144 config NEED_SG_DMA_LENGTH
147 config GENERIC_ISA_DMA
149 depends on ISA_DMA_API
154 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
156 config GENERIC_BUG_RELATIVE_POINTERS
159 config GENERIC_HWEIGHT
165 config ARCH_MAY_HAVE_PC_FDC
167 depends on ISA_DMA_API
169 config RWSEM_GENERIC_SPINLOCK
173 config RWSEM_XCHGADD_ALGORITHM
177 config GENERIC_CALIBRATE_DELAY
180 config ARCH_HAS_CPU_RELAX
183 config ARCH_HAS_DEFAULT_IDLE
186 config ARCH_HAS_CACHE_LINE_SIZE
189 config ARCH_HAS_CPU_AUTOPROBE
192 config HAVE_SETUP_PER_CPU_AREA
195 config NEED_PER_CPU_EMBED_FIRST_CHUNK
198 config NEED_PER_CPU_PAGE_FIRST_CHUNK
201 config ARCH_HIBERNATION_POSSIBLE
204 config ARCH_SUSPEND_POSSIBLE
215 config ARCH_SUPPORTS_OPTIMIZED_INLINING
218 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
221 config HAVE_INTEL_TXT
223 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
227 depends on X86_32 && SMP
231 depends on X86_64 && SMP
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
241 config ARCH_HWEIGHT_CFLAGS
243 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
244 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
246 config ARCH_CPU_PROBE_RELEASE
248 depends on HOTPLUG_CPU
250 config ARCH_SUPPORTS_UPROBES
253 source "init/Kconfig"
254 source "kernel/Kconfig.freezer"
256 menu "Processor type and features"
259 bool "DMA memory allocation support" if EXPERT
262 DMA memory allocation support allows devices with less than 32-bit
263 addressing to allocate within the first 16MB of address space.
264 Disable if no such devices will be used.
269 bool "Symmetric multi-processing support"
271 This enables support for systems with more than one CPU. If you have
272 a system with only one CPU, like most personal computers, say N. If
273 you have a system with more than one CPU, say Y.
275 If you say N here, the kernel will run on single and multiprocessor
276 machines, but will use only one CPU of a multiprocessor machine. If
277 you say Y here, the kernel will run on many, but not all,
278 singleprocessor machines. On a singleprocessor machine, the kernel
279 will run faster if you say N here.
281 Note that if you say Y here and choose architecture "586" or
282 "Pentium" under "Processor family", the kernel will not work on 486
283 architectures. Similarly, multiprocessor kernels for the "PPro"
284 architecture may not work on all Pentium based boards.
286 People using multiprocessor machines who say Y here should also say
287 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
288 Management" code will be disabled if you say Y here.
290 See also <file:Documentation/x86/i386/IO-APIC.txt>,
291 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
292 <http://www.tldp.org/docs.html#howto>.
294 If you don't know what to do here, say N.
297 bool "Support x2apic"
298 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
300 This enables x2apic support on CPUs that have this feature.
302 This allows 32-bit apic IDs (so it can support very large systems),
303 and accesses the local apic via MSRs not via mmio.
305 If you don't know what to do here, say N.
308 bool "Enable MPS table" if ACPI
310 depends on X86_LOCAL_APIC
312 For old smp systems that do not have proper acpi support. Newer systems
313 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
316 bool "Support for big SMP systems with more than 8 CPUs"
317 depends on X86_32 && SMP
319 This option is needed for the systems that have more than 8 CPUs
322 config X86_EXTENDED_PLATFORM
323 bool "Support for extended (non-PC) x86 platforms"
326 If you disable this option then the kernel will only support
327 standard PC platforms. (which covers the vast majority of
330 If you enable this option then you'll be able to select support
331 for the following (non-PC) 32 bit x86 platforms:
335 SGI 320/540 (Visual Workstation)
336 STA2X11-based (e.g. Northville)
337 Summit/EXA (IBM x440)
338 Unisys ES7000 IA32 series
339 Moorestown MID devices
341 If you have one of these systems, or if you want to build a
342 generic distribution kernel, say Y here - otherwise say N.
346 config X86_EXTENDED_PLATFORM
347 bool "Support for extended (non-PC) x86 platforms"
350 If you disable this option then the kernel will only support
351 standard PC platforms. (which covers the vast majority of
354 If you enable this option then you'll be able to select support
355 for the following (non-PC) 64 bit x86 platforms:
360 If you have one of these systems, or if you want to build a
361 generic distribution kernel, say Y here - otherwise say N.
363 # This is an alphabetically sorted list of 64 bit extended platforms
364 # Please maintain the alphabetic order if and when there are additions
366 bool "Numascale NumaChip"
368 depends on X86_EXTENDED_PLATFORM
371 depends on X86_X2APIC
373 Adds support for Numascale NumaChip large-SMP systems. Needed to
374 enable more than ~168 cores.
375 If you don't have one of these, you should say N here.
379 select PARAVIRT_GUEST
381 depends on X86_64 && PCI
382 depends on X86_EXTENDED_PLATFORM
385 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
386 supposed to run on these EM64T-based machines. Only choose this option
387 if you have one of these machines.
390 bool "SGI Ultraviolet"
392 depends on X86_EXTENDED_PLATFORM
394 depends on X86_X2APIC
396 This option is needed in order to support SGI Ultraviolet systems.
397 If you don't have one of these, you should say N here.
399 # Following is an alphabetically sorted list of 32 bit extended platforms
400 # Please maintain the alphabetic order if and when there are additions
403 bool "CE4100 TV platform"
405 depends on PCI_GODIRECT
407 depends on X86_EXTENDED_PLATFORM
408 select X86_REBOOTFIXUPS
410 select OF_EARLY_FLATTREE
413 Select for the Intel CE media processor (CE4100) SOC.
414 This option compiles in support for the CE4100 SOC for settop
415 boxes and media devices.
417 config X86_WANT_INTEL_MID
418 bool "Intel MID platform support"
420 depends on X86_EXTENDED_PLATFORM
422 Select to build a kernel capable of supporting Intel MID platform
423 systems which do not have the PCI legacy interfaces (Moorestown,
424 Medfield). If you are building for a PC class system say N here.
426 if X86_WANT_INTEL_MID
432 bool "Medfield MID platform"
435 depends on X86_IO_APIC
443 select X86_PLATFORM_DEVICES
444 select MFD_INTEL_MSIC
446 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
447 Internet Device(MID) platform.
448 Unlike standard x86 PCs, Medfield does not have many legacy devices
449 nor standard legacy replacement devices/features. e.g. Medfield does
450 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
455 bool "RDC R-321x SoC"
457 depends on X86_EXTENDED_PLATFORM
459 select X86_REBOOTFIXUPS
461 This option is needed for RDC R-321x system-on-chip, also known
463 If you don't have one of these chips, you should say N here.
465 config X86_32_NON_STANDARD
466 bool "Support non-standard 32-bit SMP architectures"
467 depends on X86_32 && SMP
468 depends on X86_EXTENDED_PLATFORM
470 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
471 STA2X11, default subarchitectures. It is intended for a generic
472 binary kernel. If you select them all, kernel will probe it
473 one by one and will fallback to default.
475 # Alphabetically sorted list of Non standard 32 bit platforms
478 bool "NUMAQ (IBM/Sequent)"
479 depends on X86_32_NON_STANDARD
484 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
485 NUMA multiquad box. This changes the way that processors are
486 bootstrapped, and uses Clustered Logical APIC addressing mode instead
487 of Flat Logical. You will need a new lynxer.elf file to flash your
488 firmware with - send email to <Martin.Bligh@us.ibm.com>.
490 config X86_SUPPORTS_MEMORY_FAILURE
492 # MCE code calls memory_failure():
494 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
495 depends on !X86_NUMAQ
496 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
497 depends on X86_64 || !SPARSEMEM
498 select ARCH_SUPPORTS_MEMORY_FAILURE
501 bool "SGI 320/540 (Visual Workstation)"
502 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
503 depends on X86_32_NON_STANDARD
505 The SGI Visual Workstation series is an IA32-based workstation
506 based on SGI systems chips with some legacy PC hardware attached.
508 Say Y here to create a kernel to run on the SGI 320 or 540.
510 A kernel compiled for the Visual Workstation will run on general
511 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
514 bool "STA2X11 Companion Chip Support"
515 depends on X86_32_NON_STANDARD && PCI
516 select X86_DEV_DMA_OPS
520 select ARCH_REQUIRE_GPIOLIB
523 This adds support for boards based on the STA2X11 IO-Hub,
524 a.k.a. "ConneXt". The chip is used in place of the standard
525 PC chipset, so all "standard" peripherals are missing. If this
526 option is selected the kernel will still be able to boot on
527 standard PC machines.
530 bool "Summit/EXA (IBM x440)"
531 depends on X86_32_NON_STANDARD
533 This option is needed for IBM systems that use the Summit/EXA chipset.
534 In particular, it is needed for the x440.
537 bool "Unisys ES7000 IA32 series"
538 depends on X86_32_NON_STANDARD && X86_BIGSMP
540 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
541 supposed to run on an IA32-based Unisys ES7000 system.
544 tristate "Eurobraille/Iris poweroff module"
547 The Iris machines from EuroBraille do not have APM or ACPI support
548 to shut themselves down properly. A special I/O sequence is
549 needed to do so, which is what this module does at
552 This is only for Iris machines from EuroBraille.
556 config SCHED_OMIT_FRAME_POINTER
558 prompt "Single-depth WCHAN output"
561 Calculate simpler /proc/<PID>/wchan values. If this option
562 is disabled then wchan values will recurse back to the
563 caller function. This provides more accurate wchan values,
564 at the expense of slightly more scheduling overhead.
566 If in doubt, say "Y".
568 config KVMTOOL_TEST_ENABLE
569 bool "Enable options to create a bootable tools/kvm/ kernel"
575 select NETWORK_FILESYSTEMS
579 select SERIAL_8250_CONSOLE
584 select HAVE_ARCH_KGDB
587 select KGDB_SERIAL_CONSOLE
588 select VIRTUALIZATION
593 select VIRTIO_CONSOLE
599 menuconfig PARAVIRT_GUEST
600 bool "Paravirtualized guest support"
602 Say Y here to get to see options related to running Linux under
603 various hypervisors. This option alone does not add any kernel code.
605 If you say N, all options in this submenu will be skipped and disabled.
609 config PARAVIRT_TIME_ACCOUNTING
610 bool "Paravirtual steal time accounting"
614 Select this option to enable fine granularity task steal time
615 accounting. Time spent executing other tasks in parallel with
616 the current vCPU is discounted from the vCPU power. To account for
617 that, there can be a small performance impact.
619 If in doubt, say N here.
621 source "arch/x86/xen/Kconfig"
624 bool "KVM Guest support (including kvmclock)"
627 select PARAVIRT_CLOCK
628 default y if PARAVIRT_GUEST
630 This option enables various optimizations for running under the KVM
631 hypervisor. It includes a paravirtualized clock, so that instead
632 of relying on a PIT (or probably other) emulation by the
633 underlying device model, the host provides the guest with
634 timing infrastructure such as time of day, and system time
636 source "arch/x86/lguest/Kconfig"
639 bool "Enable paravirtualization code"
641 This changes the kernel so it can modify itself when it is run
642 under a hypervisor, potentially improving performance significantly
643 over full virtualization. However, when run without a hypervisor
644 the kernel is theoretically slower and slightly larger.
646 config PARAVIRT_SPINLOCKS
647 bool "Paravirtualization layer for spinlocks"
648 depends on PARAVIRT && SMP && EXPERIMENTAL
650 Paravirtualized spinlocks allow a pvops backend to replace the
651 spinlock implementation with something virtualization-friendly
652 (for example, block the virtual CPU rather than spinning).
654 Unfortunately the downside is an up to 5% performance hit on
655 native kernels, with various workloads.
657 If you are unsure how to answer this question, answer N.
659 config PARAVIRT_CLOCK
664 config PARAVIRT_DEBUG
665 bool "paravirt-ops debugging"
666 depends on PARAVIRT && DEBUG_KERNEL
668 Enable to debug paravirt_ops internals. Specifically, BUG if
669 a paravirt_op is missing when it is called.
677 This option adds a kernel parameter 'memtest', which allows memtest
679 memtest=0, mean disabled; -- default
680 memtest=1, mean do 1 test pattern;
682 memtest=4, mean do 4 test patterns.
683 If you are unsure how to answer this question, answer N.
685 config X86_SUMMIT_NUMA
687 depends on X86_32 && NUMA && X86_32_NON_STANDARD
689 config X86_CYCLONE_TIMER
691 depends on X86_SUMMIT
693 source "arch/x86/Kconfig.cpu"
697 prompt "HPET Timer Support" if X86_32
699 Use the IA-PC HPET (High Precision Event Timer) to manage
700 time in preference to the PIT and RTC, if a HPET is
702 HPET is the next generation timer replacing legacy 8254s.
703 The HPET provides a stable time base on SMP
704 systems, unlike the TSC, but it is more expensive to access,
705 as it is off-chip. You can find the HPET spec at
706 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
708 You can safely choose Y here. However, HPET will only be
709 activated if the platform and the BIOS support this feature.
710 Otherwise the 8254 will be used for timing services.
712 Choose N to continue using the legacy 8254 timer.
714 config HPET_EMULATE_RTC
716 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
719 def_bool y if X86_INTEL_MID
720 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
722 depends on X86_INTEL_MID && SFI
724 APB timer is the replacement for 8254, HPET on X86 MID platforms.
725 The APBT provides a stable time base on SMP
726 systems, unlike the TSC, but it is more expensive to access,
727 as it is off-chip. APB timers are always running regardless of CPU
728 C states, they are used as per CPU clockevent device when possible.
730 # Mark as expert because too many people got it wrong.
731 # The code disables itself when not needed.
734 bool "Enable DMI scanning" if EXPERT
736 Enabled scanning of DMI to identify machine quirks. Say Y
737 here unless you have verified that your setup is not
738 affected by entries in the DMI blacklist. Required by PNP
742 bool "GART IOMMU support" if EXPERT
745 depends on X86_64 && PCI && AMD_NB
747 Support for full DMA access of devices with 32bit memory access only
748 on systems with more than 3GB. This is usually needed for USB,
749 sound, many IDE/SATA chipsets and some other devices.
750 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
751 based hardware IOMMU and a software bounce buffer based IOMMU used
752 on Intel systems and as fallback.
753 The code is only active when needed (enough memory and limited
754 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
758 bool "IBM Calgary IOMMU support"
760 depends on X86_64 && PCI && EXPERIMENTAL
762 Support for hardware IOMMUs in IBM's xSeries x366 and x460
763 systems. Needed to run systems with more than 3GB of memory
764 properly with 32-bit PCI devices that do not support DAC
765 (Double Address Cycle). Calgary also supports bus level
766 isolation, where all DMAs pass through the IOMMU. This
767 prevents them from going anywhere except their intended
768 destination. This catches hard-to-find kernel bugs and
769 mis-behaving drivers and devices that do not use the DMA-API
770 properly to set up their DMA buffers. The IOMMU can be
771 turned off at boot time with the iommu=off parameter.
772 Normally the kernel will make the right choice by itself.
775 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
777 prompt "Should Calgary be enabled by default?"
778 depends on CALGARY_IOMMU
780 Should Calgary be enabled by default? if you choose 'y', Calgary
781 will be used (if it exists). If you choose 'n', Calgary will not be
782 used even if it exists. If you choose 'n' and would like to use
783 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
786 # need this always selected by IOMMU for the VIA workaround
790 Support for software bounce buffers used on x86-64 systems
791 which don't have a hardware IOMMU. Using this PCI devices
792 which can only access 32-bits of memory can be used on systems
793 with more than 3 GB of memory.
798 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
801 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
802 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
803 select CPUMASK_OFFSTACK
805 Enable maximum number of CPUS and NUMA Nodes for this architecture.
809 int "Maximum number of CPUs" if SMP && !MAXSMP
810 range 2 8 if SMP && X86_32 && !X86_BIGSMP
811 range 2 512 if SMP && !MAXSMP
813 default "4096" if MAXSMP
814 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
817 This allows you to specify the maximum number of CPUs which this
818 kernel will support. The maximum supported value is 512 and the
819 minimum value which makes sense is 2.
821 This is purely to save memory - each supported CPU adds
822 approximately eight kilobytes to the kernel image.
825 bool "SMT (Hyperthreading) scheduler support"
828 SMT scheduler support improves the CPU scheduler's decision making
829 when dealing with Intel Pentium 4 chips with HyperThreading at a
830 cost of slightly increased overhead in some places. If unsure say
835 prompt "Multi-core scheduler support"
838 Multi-core scheduler support improves the CPU scheduler's decision
839 making when dealing with multi-core CPU chips at a cost of slightly
840 increased overhead in some places. If unsure say N here.
842 source "kernel/Kconfig.preempt"
845 bool "Local APIC support on uniprocessors"
846 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
848 A local APIC (Advanced Programmable Interrupt Controller) is an
849 integrated interrupt controller in the CPU. If you have a single-CPU
850 system which has a processor with a local APIC, you can say Y here to
851 enable and use it. If you say Y here even though your machine doesn't
852 have a local APIC, then the kernel will still run with no slowdown at
853 all. The local APIC supports CPU-generated self-interrupts (timer,
854 performance counters), and the NMI watchdog which detects hard
858 bool "IO-APIC support on uniprocessors"
859 depends on X86_UP_APIC
861 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
862 SMP-capable replacement for PC-style interrupt controllers. Most
863 SMP systems and many recent uniprocessor systems have one.
865 If you have a single-CPU system with an IO-APIC, you can say Y here
866 to use it. If you say Y here even though your machine doesn't have
867 an IO-APIC, then the kernel will still run with no slowdown at all.
869 config X86_LOCAL_APIC
871 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
875 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
877 config X86_VISWS_APIC
879 depends on X86_32 && X86_VISWS
881 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
882 bool "Reroute for broken boot IRQs"
883 depends on X86_IO_APIC
885 This option enables a workaround that fixes a source of
886 spurious interrupts. This is recommended when threaded
887 interrupt handling is used on systems where the generation of
888 superfluous "boot interrupts" cannot be disabled.
890 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
891 entry in the chipset's IO-APIC is masked (as, e.g. the RT
892 kernel does during interrupt handling). On chipsets where this
893 boot IRQ generation cannot be disabled, this workaround keeps
894 the original IRQ line masked so that only the equivalent "boot
895 IRQ" is delivered to the CPUs. The workaround also tells the
896 kernel to set up the IRQ handler on the boot IRQ line. In this
897 way only one interrupt is delivered to the kernel. Otherwise
898 the spurious second interrupt may cause the kernel to bring
899 down (vital) interrupt lines.
901 Only affects "broken" chipsets. Interrupt sharing may be
902 increased on these systems.
905 bool "Machine Check / overheating reporting"
908 Machine Check support allows the processor to notify the
909 kernel if it detects a problem (e.g. overheating, data corruption).
910 The action the kernel takes depends on the severity of the problem,
911 ranging from warning messages to halting the machine.
915 prompt "Intel MCE features"
916 depends on X86_MCE && X86_LOCAL_APIC
918 Additional support for intel specific MCE features such as
923 prompt "AMD MCE features"
924 depends on X86_MCE && X86_LOCAL_APIC
926 Additional support for AMD specific MCE features such as
927 the DRAM Error Threshold.
929 config X86_ANCIENT_MCE
930 bool "Support for old Pentium 5 / WinChip machine checks"
931 depends on X86_32 && X86_MCE
933 Include support for machine check handling on old Pentium 5 or WinChip
934 systems. These typically need to be enabled explicitely on the command
937 config X86_MCE_THRESHOLD
938 depends on X86_MCE_AMD || X86_MCE_INTEL
941 config X86_MCE_INJECT
943 tristate "Machine check injector support"
945 Provide support for injecting machine checks for testing purposes.
946 If you don't know what a machine check is and you don't do kernel
947 QA it is safe to say n.
949 config X86_THERMAL_VECTOR
951 depends on X86_MCE_INTEL
954 bool "Enable VM86 support" if EXPERT
958 This option is required by programs like DOSEMU to run 16-bit legacy
959 code on X86 processors. It also may be needed by software like
960 XFree86 to initialize some video cards via BIOS. Disabling this
961 option saves about 6k.
964 tristate "Toshiba Laptop support"
967 This adds a driver to safely access the System Management Mode of
968 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
969 not work on models with a Phoenix BIOS. The System Management Mode
970 is used to set the BIOS and power saving options on Toshiba portables.
972 For information on utilities to make use of this driver see the
973 Toshiba Linux utilities web site at:
974 <http://www.buzzard.org.uk/toshiba/>.
976 Say Y if you intend to run this kernel on a Toshiba portable.
980 tristate "Dell laptop support"
983 This adds a driver to safely access the System Management Mode
984 of the CPU on the Dell Inspiron 8000. The System Management Mode
985 is used to read cpu temperature and cooling fan status and to
986 control the fans on the I8K portables.
988 This driver has been tested only on the Inspiron 8000 but it may
989 also work with other Dell laptops. You can force loading on other
990 models by passing the parameter `force=1' to the module. Use at
993 For information on utilities to make use of this driver see the
994 I8K Linux utilities web site at:
995 <http://people.debian.org/~dz/i8k/>
997 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1000 config X86_REBOOTFIXUPS
1001 bool "Enable X86 board specific fixups for reboot"
1004 This enables chipset and/or board specific fixups to be done
1005 in order to get reboot to work correctly. This is only needed on
1006 some combinations of hardware and BIOS. The symptom, for which
1007 this config is intended, is when reboot ends with a stalled/hung
1010 Currently, the only fixup is for the Geode machines using
1011 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1013 Say Y if you want to enable the fixup. Currently, it's safe to
1014 enable this option even if you don't need it.
1018 tristate "CPU microcode loading support"
1022 If you say Y here, you will be able to update the microcode on
1023 certain Intel and AMD processors. The Intel support is for the
1024 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1025 Xeon etc. The AMD support is for families 0x10 and later. You will
1026 obviously need the actual microcode binary data itself which is not
1027 shipped with the Linux kernel.
1029 This option selects the general module only, you need to select
1030 at least one vendor specific module as well.
1032 To compile this driver as a module, choose M here: the module
1033 will be called microcode.
1035 config MICROCODE_INTEL
1036 bool "Intel microcode loading support"
1037 depends on MICROCODE
1041 This options enables microcode patch loading support for Intel
1044 For latest news and information on obtaining all the required
1045 Intel ingredients for this driver, check:
1046 <http://www.urbanmyth.org/microcode/>.
1048 config MICROCODE_AMD
1049 bool "AMD microcode loading support"
1050 depends on MICROCODE
1053 If you select this option, microcode patch loading support for AMD
1054 processors will be enabled.
1056 config MICROCODE_OLD_INTERFACE
1058 depends on MICROCODE
1061 tristate "/dev/cpu/*/msr - Model-specific register support"
1063 This device gives privileged processes access to the x86
1064 Model-Specific Registers (MSRs). It is a character device with
1065 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1066 MSR accesses are directed to a specific CPU on multi-processor
1070 tristate "/dev/cpu/*/cpuid - CPU information support"
1072 This device gives processes access to the x86 CPUID instruction to
1073 be executed on a specific processor. It is a character device
1074 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1078 prompt "High Memory Support"
1079 default HIGHMEM64G if X86_NUMAQ
1085 depends on !X86_NUMAQ
1087 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1088 However, the address space of 32-bit x86 processors is only 4
1089 Gigabytes large. That means that, if you have a large amount of
1090 physical memory, not all of it can be "permanently mapped" by the
1091 kernel. The physical memory that's not permanently mapped is called
1094 If you are compiling a kernel which will never run on a machine with
1095 more than 1 Gigabyte total physical RAM, answer "off" here (default
1096 choice and suitable for most users). This will result in a "3GB/1GB"
1097 split: 3GB are mapped so that each process sees a 3GB virtual memory
1098 space and the remaining part of the 4GB virtual memory space is used
1099 by the kernel to permanently map as much physical memory as
1102 If the machine has between 1 and 4 Gigabytes physical RAM, then
1105 If more than 4 Gigabytes is used then answer "64GB" here. This
1106 selection turns Intel PAE (Physical Address Extension) mode on.
1107 PAE implements 3-level paging on IA32 processors. PAE is fully
1108 supported by Linux, PAE mode is implemented on all recent Intel
1109 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1110 then the kernel will not boot on CPUs that don't support PAE!
1112 The actual amount of total physical memory will either be
1113 auto detected or can be forced by using a kernel command line option
1114 such as "mem=256M". (Try "man bootparam" or see the documentation of
1115 your boot loader (lilo or loadlin) about how to pass options to the
1116 kernel at boot time.)
1118 If unsure, say "off".
1122 depends on !X86_NUMAQ
1124 Select this if you have a 32-bit processor and between 1 and 4
1125 gigabytes of physical RAM.
1129 depends on !M386 && !M486
1132 Select this if you have a 32-bit processor and more than 4
1133 gigabytes of physical RAM.
1138 depends on EXPERIMENTAL
1139 prompt "Memory split" if EXPERT
1143 Select the desired split between kernel and user memory.
1145 If the address range available to the kernel is less than the
1146 physical memory installed, the remaining memory will be available
1147 as "high memory". Accessing high memory is a little more costly
1148 than low memory, as it needs to be mapped into the kernel first.
1149 Note that increasing the kernel address space limits the range
1150 available to user programs, making the address space there
1151 tighter. Selecting anything other than the default 3G/1G split
1152 will also likely make your kernel incompatible with binary-only
1155 If you are not absolutely sure what you are doing, leave this
1159 bool "3G/1G user/kernel split"
1160 config VMSPLIT_3G_OPT
1162 bool "3G/1G user/kernel split (for full 1G low memory)"
1164 bool "2G/2G user/kernel split"
1165 config VMSPLIT_2G_OPT
1167 bool "2G/2G user/kernel split (for full 2G low memory)"
1169 bool "1G/3G user/kernel split"
1174 default 0xB0000000 if VMSPLIT_3G_OPT
1175 default 0x80000000 if VMSPLIT_2G
1176 default 0x78000000 if VMSPLIT_2G_OPT
1177 default 0x40000000 if VMSPLIT_1G
1183 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1186 bool "PAE (Physical Address Extension) Support"
1187 depends on X86_32 && !HIGHMEM4G
1189 PAE is required for NX support, and furthermore enables
1190 larger swapspace support for non-overcommit purposes. It
1191 has the cost of more pagetable lookup overhead, and also
1192 consumes more pagetable space per process.
1194 config ARCH_PHYS_ADDR_T_64BIT
1196 depends on X86_64 || X86_PAE
1198 config ARCH_DMA_ADDR_T_64BIT
1200 depends on X86_64 || HIGHMEM64G
1202 config DIRECT_GBPAGES
1203 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1207 Allow the kernel linear mapping to use 1GB pages on CPUs that
1208 support it. This can improve the kernel's performance a tiny bit by
1209 reducing TLB pressure. If in doubt, say "Y".
1211 # Common NUMA Features
1213 bool "Numa Memory Allocation and Scheduler Support"
1215 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1216 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1218 Enable NUMA (Non Uniform Memory Access) support.
1220 The kernel will try to allocate memory used by a CPU on the
1221 local memory controller of the CPU and add some more
1222 NUMA awareness to the kernel.
1224 For 64-bit this is recommended if the system is Intel Core i7
1225 (or later), AMD Opteron, or EM64T NUMA.
1227 For 32-bit this is only needed on (rare) 32-bit-only platforms
1228 that support NUMA topologies, such as NUMAQ / Summit, or if you
1229 boot a 32-bit kernel on a 64-bit NUMA platform.
1231 Otherwise, you should say N.
1233 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1234 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1238 prompt "Old style AMD Opteron NUMA detection"
1239 depends on X86_64 && NUMA && PCI
1241 Enable AMD NUMA node topology detection. You should say Y here if
1242 you have a multi processor AMD system. This uses an old method to
1243 read the NUMA configuration directly from the builtin Northbridge
1244 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1245 which also takes priority if both are compiled in.
1247 config X86_64_ACPI_NUMA
1249 prompt "ACPI NUMA detection"
1250 depends on X86_64 && NUMA && ACPI && PCI
1253 Enable ACPI SRAT based node topology detection.
1255 # Some NUMA nodes have memory ranges that span
1256 # other nodes. Even though a pfn is valid and
1257 # between a node's start and end pfns, it may not
1258 # reside on that node. See memmap_init_zone()
1260 config NODES_SPAN_OTHER_NODES
1262 depends on X86_64_ACPI_NUMA
1265 bool "NUMA emulation"
1268 Enable NUMA emulation. A flat machine will be split
1269 into virtual nodes when booted with "numa=fake=N", where N is the
1270 number of nodes. This is only useful for debugging.
1273 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1275 default "10" if MAXSMP
1276 default "6" if X86_64
1277 default "4" if X86_NUMAQ
1279 depends on NEED_MULTIPLE_NODES
1281 Specify the maximum number of NUMA Nodes available on the target
1282 system. Increases memory reserved to accommodate various tables.
1284 config HAVE_ARCH_ALLOC_REMAP
1286 depends on X86_32 && NUMA
1288 config ARCH_HAVE_MEMORY_PRESENT
1290 depends on X86_32 && DISCONTIGMEM
1292 config NEED_NODE_MEMMAP_SIZE
1294 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1296 config ARCH_FLATMEM_ENABLE
1298 depends on X86_32 && !NUMA
1300 config ARCH_DISCONTIGMEM_ENABLE
1302 depends on NUMA && X86_32
1304 config ARCH_DISCONTIGMEM_DEFAULT
1306 depends on NUMA && X86_32
1308 config ARCH_SPARSEMEM_ENABLE
1310 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1311 select SPARSEMEM_STATIC if X86_32
1312 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1314 config ARCH_SPARSEMEM_DEFAULT
1318 config ARCH_SELECT_MEMORY_MODEL
1320 depends on ARCH_SPARSEMEM_ENABLE
1322 config ARCH_MEMORY_PROBE
1324 depends on X86_64 && MEMORY_HOTPLUG
1326 config ARCH_PROC_KCORE_TEXT
1328 depends on X86_64 && PROC_KCORE
1330 config ILLEGAL_POINTER_VALUE
1333 default 0xdead000000000000 if X86_64
1338 bool "Allocate 3rd-level pagetables from highmem"
1341 The VM uses one page table entry for each page of physical memory.
1342 For systems with a lot of RAM, this can be wasteful of precious
1343 low memory. Setting this option will put user-space page table
1344 entries in high memory.
1346 config X86_CHECK_BIOS_CORRUPTION
1347 bool "Check for low memory corruption"
1349 Periodically check for memory corruption in low memory, which
1350 is suspected to be caused by BIOS. Even when enabled in the
1351 configuration, it is disabled at runtime. Enable it by
1352 setting "memory_corruption_check=1" on the kernel command
1353 line. By default it scans the low 64k of memory every 60
1354 seconds; see the memory_corruption_check_size and
1355 memory_corruption_check_period parameters in
1356 Documentation/kernel-parameters.txt to adjust this.
1358 When enabled with the default parameters, this option has
1359 almost no overhead, as it reserves a relatively small amount
1360 of memory and scans it infrequently. It both detects corruption
1361 and prevents it from affecting the running system.
1363 It is, however, intended as a diagnostic tool; if repeatable
1364 BIOS-originated corruption always affects the same memory,
1365 you can use memmap= to prevent the kernel from using that
1368 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1369 bool "Set the default setting of memory_corruption_check"
1370 depends on X86_CHECK_BIOS_CORRUPTION
1373 Set whether the default state of memory_corruption_check is
1376 config X86_RESERVE_LOW
1377 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1381 Specify the amount of low memory to reserve for the BIOS.
1383 The first page contains BIOS data structures that the kernel
1384 must not use, so that page must always be reserved.
1386 By default we reserve the first 64K of physical RAM, as a
1387 number of BIOSes are known to corrupt that memory range
1388 during events such as suspend/resume or monitor cable
1389 insertion, so it must not be used by the kernel.
1391 You can set this to 4 if you are absolutely sure that you
1392 trust the BIOS to get all its memory reservations and usages
1393 right. If you know your BIOS have problems beyond the
1394 default 64K area, you can set this to 640 to avoid using the
1395 entire low memory range.
1397 If you have doubts about the BIOS (e.g. suspend/resume does
1398 not work or there's kernel crashes after certain hardware
1399 hotplug events) then you might want to enable
1400 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1401 typical corruption patterns.
1403 Leave this to the default value of 64 if you are unsure.
1405 config MATH_EMULATION
1407 prompt "Math emulation" if X86_32
1409 Linux can emulate a math coprocessor (used for floating point
1410 operations) if you don't have one. 486DX and Pentium processors have
1411 a math coprocessor built in, 486SX and 386 do not, unless you added
1412 a 487DX or 387, respectively. (The messages during boot time can
1413 give you some hints here ["man dmesg"].) Everyone needs either a
1414 coprocessor or this emulation.
1416 If you don't have a math coprocessor, you need to say Y here; if you
1417 say Y here even though you have a coprocessor, the coprocessor will
1418 be used nevertheless. (This behavior can be changed with the kernel
1419 command line option "no387", which comes handy if your coprocessor
1420 is broken. Try "man bootparam" or see the documentation of your boot
1421 loader (lilo or loadlin) about how to pass options to the kernel at
1422 boot time.) This means that it is a good idea to say Y here if you
1423 intend to use this kernel on different machines.
1425 More information about the internals of the Linux math coprocessor
1426 emulation can be found in <file:arch/x86/math-emu/README>.
1428 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1429 kernel, it won't hurt.
1433 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1435 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1436 the Memory Type Range Registers (MTRRs) may be used to control
1437 processor access to memory ranges. This is most useful if you have
1438 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1439 allows bus write transfers to be combined into a larger transfer
1440 before bursting over the PCI/AGP bus. This can increase performance
1441 of image write operations 2.5 times or more. Saying Y here creates a
1442 /proc/mtrr file which may be used to manipulate your processor's
1443 MTRRs. Typically the X server should use this.
1445 This code has a reasonably generic interface so that similar
1446 control registers on other processors can be easily supported
1449 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1450 Registers (ARRs) which provide a similar functionality to MTRRs. For
1451 these, the ARRs are used to emulate the MTRRs.
1452 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1453 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1454 write-combining. All of these processors are supported by this code
1455 and it makes sense to say Y here if you have one of them.
1457 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1458 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1459 can lead to all sorts of problems, so it's good to say Y here.
1461 You can safely say Y even if your machine doesn't have MTRRs, you'll
1462 just add about 9 KB to your kernel.
1464 See <file:Documentation/x86/mtrr.txt> for more information.
1466 config MTRR_SANITIZER
1468 prompt "MTRR cleanup support"
1471 Convert MTRR layout from continuous to discrete, so X drivers can
1472 add writeback entries.
1474 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1475 The largest mtrr entry size for a continuous block can be set with
1480 config MTRR_SANITIZER_ENABLE_DEFAULT
1481 int "MTRR cleanup enable value (0-1)"
1484 depends on MTRR_SANITIZER
1486 Enable mtrr cleanup default value
1488 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1489 int "MTRR cleanup spare reg num (0-7)"
1492 depends on MTRR_SANITIZER
1494 mtrr cleanup spare entries default, it can be changed via
1495 mtrr_spare_reg_nr=N on the kernel command line.
1499 prompt "x86 PAT support" if EXPERT
1502 Use PAT attributes to setup page level cache control.
1504 PATs are the modern equivalents of MTRRs and are much more
1505 flexible than MTRRs.
1507 Say N here if you see bootup problems (boot crash, boot hang,
1508 spontaneous reboots) or a non-working video driver.
1512 config ARCH_USES_PG_UNCACHED
1518 prompt "x86 architectural random number generator" if EXPERT
1520 Enable the x86 architectural RDRAND instruction
1521 (Intel Bull Mountain technology) to generate random numbers.
1522 If supported, this is a high bandwidth, cryptographically
1523 secure hardware random number generator.
1527 prompt "Supervisor Mode Access Prevention" if EXPERT
1529 Supervisor Mode Access Prevention (SMAP) is a security
1530 feature in newer Intel processors. There is a small
1531 performance cost if this enabled and turned on; there is
1532 also a small increase in the kernel size if this is enabled.
1537 bool "EFI runtime service support"
1540 This enables the kernel to use EFI runtime services that are
1541 available (such as the EFI variable services).
1543 This option is only useful on systems that have EFI firmware.
1544 In addition, you should use the latest ELILO loader available
1545 at <http://elilo.sourceforge.net> in order to take advantage
1546 of EFI runtime services. However, even with this option, the
1547 resultant kernel should continue to boot on existing non-EFI
1551 bool "EFI stub support"
1554 This kernel feature allows a bzImage to be loaded directly
1555 by EFI firmware without the use of a bootloader.
1557 See Documentation/x86/efi-stub.txt for more information.
1561 prompt "Enable seccomp to safely compute untrusted bytecode"
1563 This kernel feature is useful for number crunching applications
1564 that may need to compute untrusted bytecode during their
1565 execution. By using pipes or other transports made available to
1566 the process as file descriptors supporting the read/write
1567 syscalls, it's possible to isolate those applications in
1568 their own address space using seccomp. Once seccomp is
1569 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1570 and the task is only allowed to execute a few safe syscalls
1571 defined by each seccomp mode.
1573 If unsure, say Y. Only embedded should say N here.
1575 config CC_STACKPROTECTOR
1576 bool "Enable -fstack-protector buffer overflow detection"
1578 This option turns on the -fstack-protector GCC feature. This
1579 feature puts, at the beginning of functions, a canary value on
1580 the stack just before the return address, and validates
1581 the value just before actually returning. Stack based buffer
1582 overflows (that need to overwrite this return address) now also
1583 overwrite the canary, which gets detected and the attack is then
1584 neutralized via a kernel panic.
1586 This feature requires gcc version 4.2 or above, or a distribution
1587 gcc with the feature backported. Older versions are automatically
1588 detected and for those versions, this configuration option is
1589 ignored. (and a warning is printed during bootup)
1591 source kernel/Kconfig.hz
1594 bool "kexec system call"
1596 kexec is a system call that implements the ability to shutdown your
1597 current kernel, and to start another kernel. It is like a reboot
1598 but it is independent of the system firmware. And like a reboot
1599 you can start any kernel with it, not just Linux.
1601 The name comes from the similarity to the exec system call.
1603 It is an ongoing process to be certain the hardware in a machine
1604 is properly shutdown, so do not be surprised if this code does not
1605 initially work for you. It may help to enable device hotplugging
1606 support. As of this writing the exact hardware interface is
1607 strongly in flux, so no good recommendation can be made.
1610 bool "kernel crash dumps"
1611 depends on X86_64 || (X86_32 && HIGHMEM)
1613 Generate crash dump after being started by kexec.
1614 This should be normally only set in special crash dump kernels
1615 which are loaded in the main kernel with kexec-tools into
1616 a specially reserved region and then later executed after
1617 a crash by kdump/kexec. The crash dump kernel must be compiled
1618 to a memory address not used by the main kernel or BIOS using
1619 PHYSICAL_START, or it must be built as a relocatable image
1620 (CONFIG_RELOCATABLE=y).
1621 For more details see Documentation/kdump/kdump.txt
1624 bool "kexec jump (EXPERIMENTAL)"
1625 depends on EXPERIMENTAL
1626 depends on KEXEC && HIBERNATION
1628 Jump between original kernel and kexeced kernel and invoke
1629 code in physical address mode via KEXEC
1631 config PHYSICAL_START
1632 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1635 This gives the physical address where the kernel is loaded.
1637 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1638 bzImage will decompress itself to above physical address and
1639 run from there. Otherwise, bzImage will run from the address where
1640 it has been loaded by the boot loader and will ignore above physical
1643 In normal kdump cases one does not have to set/change this option
1644 as now bzImage can be compiled as a completely relocatable image
1645 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1646 address. This option is mainly useful for the folks who don't want
1647 to use a bzImage for capturing the crash dump and want to use a
1648 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1649 to be specifically compiled to run from a specific memory area
1650 (normally a reserved region) and this option comes handy.
1652 So if you are using bzImage for capturing the crash dump,
1653 leave the value here unchanged to 0x1000000 and set
1654 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1655 for capturing the crash dump change this value to start of
1656 the reserved region. In other words, it can be set based on
1657 the "X" value as specified in the "crashkernel=YM@XM"
1658 command line boot parameter passed to the panic-ed
1659 kernel. Please take a look at Documentation/kdump/kdump.txt
1660 for more details about crash dumps.
1662 Usage of bzImage for capturing the crash dump is recommended as
1663 one does not have to build two kernels. Same kernel can be used
1664 as production kernel and capture kernel. Above option should have
1665 gone away after relocatable bzImage support is introduced. But it
1666 is present because there are users out there who continue to use
1667 vmlinux for dump capture. This option should go away down the
1670 Don't change this unless you know what you are doing.
1673 bool "Build a relocatable kernel"
1676 This builds a kernel image that retains relocation information
1677 so it can be loaded someplace besides the default 1MB.
1678 The relocations tend to make the kernel binary about 10% larger,
1679 but are discarded at runtime.
1681 One use is for the kexec on panic case where the recovery kernel
1682 must live at a different physical address than the primary
1685 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1686 it has been loaded at and the compile time physical address
1687 (CONFIG_PHYSICAL_START) is ignored.
1689 # Relocation on x86-32 needs some additional build support
1690 config X86_NEED_RELOCS
1692 depends on X86_32 && RELOCATABLE
1694 config PHYSICAL_ALIGN
1695 hex "Alignment value to which kernel should be aligned" if X86_32
1697 range 0x2000 0x1000000
1699 This value puts the alignment restrictions on physical address
1700 where kernel is loaded and run from. Kernel is compiled for an
1701 address which meets above alignment restriction.
1703 If bootloader loads the kernel at a non-aligned address and
1704 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1705 address aligned to above value and run from there.
1707 If bootloader loads the kernel at a non-aligned address and
1708 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1709 load address and decompress itself to the address it has been
1710 compiled for and run from there. The address for which kernel is
1711 compiled already meets above alignment restrictions. Hence the
1712 end result is that kernel runs from a physical address meeting
1713 above alignment restrictions.
1715 Don't change this unless you know what you are doing.
1718 bool "Support for hot-pluggable CPUs"
1719 depends on SMP && HOTPLUG
1721 Say Y here to allow turning CPUs off and on. CPUs can be
1722 controlled through /sys/devices/system/cpu.
1723 ( Note: power management support will enable this option
1724 automatically on SMP systems. )
1725 Say N if you want to disable CPU hotplug.
1729 prompt "Compat VDSO support"
1730 depends on X86_32 || IA32_EMULATION
1732 Map the 32-bit VDSO to the predictable old-style address too.
1734 Say N here if you are running a sufficiently recent glibc
1735 version (2.3.3 or later), to remove the high-mapped
1736 VDSO mapping and to exclusively use the randomized VDSO.
1741 bool "Built-in kernel command line"
1743 Allow for specifying boot arguments to the kernel at
1744 build time. On some systems (e.g. embedded ones), it is
1745 necessary or convenient to provide some or all of the
1746 kernel boot arguments with the kernel itself (that is,
1747 to not rely on the boot loader to provide them.)
1749 To compile command line arguments into the kernel,
1750 set this option to 'Y', then fill in the
1751 the boot arguments in CONFIG_CMDLINE.
1753 Systems with fully functional boot loaders (i.e. non-embedded)
1754 should leave this option set to 'N'.
1757 string "Built-in kernel command string"
1758 depends on CMDLINE_BOOL
1761 Enter arguments here that should be compiled into the kernel
1762 image and used at boot time. If the boot loader provides a
1763 command line at boot time, it is appended to this string to
1764 form the full kernel command line, when the system boots.
1766 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1767 change this behavior.
1769 In most cases, the command line (whether built-in or provided
1770 by the boot loader) should specify the device for the root
1773 config CMDLINE_OVERRIDE
1774 bool "Built-in command line overrides boot loader arguments"
1775 depends on CMDLINE_BOOL
1777 Set this option to 'Y' to have the kernel ignore the boot loader
1778 command line, and use ONLY the built-in command line.
1780 This is used to work around broken boot loaders. This should
1781 be set to 'N' under normal conditions.
1785 config ARCH_ENABLE_MEMORY_HOTPLUG
1787 depends on X86_64 || (X86_32 && HIGHMEM)
1789 config ARCH_ENABLE_MEMORY_HOTREMOVE
1791 depends on MEMORY_HOTPLUG
1793 config USE_PERCPU_NUMA_NODE_ID
1797 menu "Power management and ACPI options"
1799 config ARCH_HIBERNATION_HEADER
1801 depends on X86_64 && HIBERNATION
1803 source "kernel/power/Kconfig"
1805 source "drivers/acpi/Kconfig"
1807 source "drivers/sfi/Kconfig"
1814 tristate "APM (Advanced Power Management) BIOS support"
1815 depends on X86_32 && PM_SLEEP
1817 APM is a BIOS specification for saving power using several different
1818 techniques. This is mostly useful for battery powered laptops with
1819 APM compliant BIOSes. If you say Y here, the system time will be
1820 reset after a RESUME operation, the /proc/apm device will provide
1821 battery status information, and user-space programs will receive
1822 notification of APM "events" (e.g. battery status change).
1824 If you select "Y" here, you can disable actual use of the APM
1825 BIOS by passing the "apm=off" option to the kernel at boot time.
1827 Note that the APM support is almost completely disabled for
1828 machines with more than one CPU.
1830 In order to use APM, you will need supporting software. For location
1831 and more information, read <file:Documentation/power/apm-acpi.txt>
1832 and the Battery Powered Linux mini-HOWTO, available from
1833 <http://www.tldp.org/docs.html#howto>.
1835 This driver does not spin down disk drives (see the hdparm(8)
1836 manpage ("man 8 hdparm") for that), and it doesn't turn off
1837 VESA-compliant "green" monitors.
1839 This driver does not support the TI 4000M TravelMate and the ACER
1840 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1841 desktop machines also don't have compliant BIOSes, and this driver
1842 may cause those machines to panic during the boot phase.
1844 Generally, if you don't have a battery in your machine, there isn't
1845 much point in using this driver and you should say N. If you get
1846 random kernel OOPSes or reboots that don't seem to be related to
1847 anything, try disabling/enabling this option (or disabling/enabling
1850 Some other things you should try when experiencing seemingly random,
1853 1) make sure that you have enough swap space and that it is
1855 2) pass the "no-hlt" option to the kernel
1856 3) switch on floating point emulation in the kernel and pass
1857 the "no387" option to the kernel
1858 4) pass the "floppy=nodma" option to the kernel
1859 5) pass the "mem=4M" option to the kernel (thereby disabling
1860 all but the first 4 MB of RAM)
1861 6) make sure that the CPU is not over clocked.
1862 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1863 8) disable the cache from your BIOS settings
1864 9) install a fan for the video card or exchange video RAM
1865 10) install a better fan for the CPU
1866 11) exchange RAM chips
1867 12) exchange the motherboard.
1869 To compile this driver as a module, choose M here: the
1870 module will be called apm.
1874 config APM_IGNORE_USER_SUSPEND
1875 bool "Ignore USER SUSPEND"
1877 This option will ignore USER SUSPEND requests. On machines with a
1878 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1879 series notebooks, it is necessary to say Y because of a BIOS bug.
1881 config APM_DO_ENABLE
1882 bool "Enable PM at boot time"
1884 Enable APM features at boot time. From page 36 of the APM BIOS
1885 specification: "When disabled, the APM BIOS does not automatically
1886 power manage devices, enter the Standby State, enter the Suspend
1887 State, or take power saving steps in response to CPU Idle calls."
1888 This driver will make CPU Idle calls when Linux is idle (unless this
1889 feature is turned off -- see "Do CPU IDLE calls", below). This
1890 should always save battery power, but more complicated APM features
1891 will be dependent on your BIOS implementation. You may need to turn
1892 this option off if your computer hangs at boot time when using APM
1893 support, or if it beeps continuously instead of suspending. Turn
1894 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1895 T400CDT. This is off by default since most machines do fine without
1899 bool "Make CPU Idle calls when idle"
1901 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1902 On some machines, this can activate improved power savings, such as
1903 a slowed CPU clock rate, when the machine is idle. These idle calls
1904 are made after the idle loop has run for some length of time (e.g.,
1905 333 mS). On some machines, this will cause a hang at boot time or
1906 whenever the CPU becomes idle. (On machines with more than one CPU,
1907 this option does nothing.)
1909 config APM_DISPLAY_BLANK
1910 bool "Enable console blanking using APM"
1912 Enable console blanking using the APM. Some laptops can use this to
1913 turn off the LCD backlight when the screen blanker of the Linux
1914 virtual console blanks the screen. Note that this is only used by
1915 the virtual console screen blanker, and won't turn off the backlight
1916 when using the X Window system. This also doesn't have anything to
1917 do with your VESA-compliant power-saving monitor. Further, this
1918 option doesn't work for all laptops -- it might not turn off your
1919 backlight at all, or it might print a lot of errors to the console,
1920 especially if you are using gpm.
1922 config APM_ALLOW_INTS
1923 bool "Allow interrupts during APM BIOS calls"
1925 Normally we disable external interrupts while we are making calls to
1926 the APM BIOS as a measure to lessen the effects of a badly behaving
1927 BIOS implementation. The BIOS should reenable interrupts if it
1928 needs to. Unfortunately, some BIOSes do not -- especially those in
1929 many of the newer IBM Thinkpads. If you experience hangs when you
1930 suspend, try setting this to Y. Otherwise, say N.
1934 source "drivers/cpufreq/Kconfig"
1936 source "drivers/cpuidle/Kconfig"
1938 source "drivers/idle/Kconfig"
1943 menu "Bus options (PCI etc.)"
1948 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1950 Find out whether you have a PCI motherboard. PCI is the name of a
1951 bus system, i.e. the way the CPU talks to the other stuff inside
1952 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1953 VESA. If you have PCI, say Y, otherwise N.
1956 prompt "PCI access mode"
1957 depends on X86_32 && PCI
1960 On PCI systems, the BIOS can be used to detect the PCI devices and
1961 determine their configuration. However, some old PCI motherboards
1962 have BIOS bugs and may crash if this is done. Also, some embedded
1963 PCI-based systems don't have any BIOS at all. Linux can also try to
1964 detect the PCI hardware directly without using the BIOS.
1966 With this option, you can specify how Linux should detect the
1967 PCI devices. If you choose "BIOS", the BIOS will be used,
1968 if you choose "Direct", the BIOS won't be used, and if you
1969 choose "MMConfig", then PCI Express MMCONFIG will be used.
1970 If you choose "Any", the kernel will try MMCONFIG, then the
1971 direct access method and falls back to the BIOS if that doesn't
1972 work. If unsure, go with the default, which is "Any".
1977 config PCI_GOMMCONFIG
1994 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1996 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1999 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2003 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2007 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2011 depends on PCI && XEN
2019 bool "Support mmconfig PCI config space access"
2020 depends on X86_64 && PCI && ACPI
2022 config PCI_CNB20LE_QUIRK
2023 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2024 depends on PCI && EXPERIMENTAL
2026 Read the PCI windows out of the CNB20LE host bridge. This allows
2027 PCI hotplug to work on systems with the CNB20LE chipset which do
2030 There's no public spec for this chipset, and this functionality
2031 is known to be incomplete.
2033 You should say N unless you know you need this.
2035 source "drivers/pci/pcie/Kconfig"
2037 source "drivers/pci/Kconfig"
2039 # x86_64 have no ISA slots, but can have ISA-style DMA.
2041 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2044 Enables ISA-style DMA support for devices requiring such controllers.
2052 Find out whether you have ISA slots on your motherboard. ISA is the
2053 name of a bus system, i.e. the way the CPU talks to the other stuff
2054 inside your box. Other bus systems are PCI, EISA, MicroChannel
2055 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2056 newer boards don't support it. If you have ISA, say Y, otherwise N.
2062 The Extended Industry Standard Architecture (EISA) bus was
2063 developed as an open alternative to the IBM MicroChannel bus.
2065 The EISA bus provided some of the features of the IBM MicroChannel
2066 bus while maintaining backward compatibility with cards made for
2067 the older ISA bus. The EISA bus saw limited use between 1988 and
2068 1995 when it was made obsolete by the PCI bus.
2070 Say Y here if you are building a kernel for an EISA-based machine.
2074 source "drivers/eisa/Kconfig"
2077 tristate "NatSemi SCx200 support"
2079 This provides basic support for National Semiconductor's
2080 (now AMD's) Geode processors. The driver probes for the
2081 PCI-IDs of several on-chip devices, so its a good dependency
2082 for other scx200_* drivers.
2084 If compiled as a module, the driver is named scx200.
2086 config SCx200HR_TIMER
2087 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2091 This driver provides a clocksource built upon the on-chip
2092 27MHz high-resolution timer. Its also a workaround for
2093 NSC Geode SC-1100's buggy TSC, which loses time when the
2094 processor goes idle (as is done by the scheduler). The
2095 other workaround is idle=poll boot option.
2098 bool "One Laptop Per Child support"
2105 Add support for detecting the unique features of the OLPC
2109 bool "OLPC XO-1 Power Management"
2110 depends on OLPC && MFD_CS5535 && PM_SLEEP
2113 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2116 bool "OLPC XO-1 Real Time Clock"
2117 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2119 Add support for the XO-1 real time clock, which can be used as a
2120 programmable wakeup source.
2123 bool "OLPC XO-1 SCI extras"
2124 depends on OLPC && OLPC_XO1_PM
2129 Add support for SCI-based features of the OLPC XO-1 laptop:
2130 - EC-driven system wakeups
2134 - AC adapter status updates
2135 - Battery status updates
2137 config OLPC_XO15_SCI
2138 bool "OLPC XO-1.5 SCI extras"
2139 depends on OLPC && ACPI
2142 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2143 - EC-driven system wakeups
2144 - AC adapter status updates
2145 - Battery status updates
2148 bool "PCEngines ALIX System Support (LED setup)"
2151 This option enables system support for the PCEngines ALIX.
2152 At present this just sets up LEDs for GPIO control on
2153 ALIX2/3/6 boards. However, other system specific setup should
2156 Note: You must still enable the drivers for GPIO and LED support
2157 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2159 Note: You have to set alix.force=1 for boards with Award BIOS.
2162 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2165 This option enables system support for the Soekris Engineering net5501.
2168 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2172 This option enables system support for the Traverse Technologies GEOS.
2178 depends on CPU_SUP_AMD && PCI
2180 source "drivers/pcmcia/Kconfig"
2182 source "drivers/pci/hotplug/Kconfig"
2185 bool "RapidIO support"
2189 If you say Y here, the kernel will include drivers and
2190 infrastructure code to support RapidIO interconnect devices.
2192 source "drivers/rapidio/Kconfig"
2197 menu "Executable file formats / Emulations"
2199 source "fs/Kconfig.binfmt"
2201 config IA32_EMULATION
2202 bool "IA32 Emulation"
2204 select COMPAT_BINFMT_ELF
2206 Include code to run legacy 32-bit programs under a
2207 64-bit kernel. You should likely turn this on, unless you're
2208 100% sure that you don't have any 32-bit programs left.
2211 tristate "IA32 a.out support"
2212 depends on IA32_EMULATION
2214 Support old a.out binaries in the 32bit emulation.
2217 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2218 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2220 Include code to run binaries for the x32 native 32-bit ABI
2221 for 64-bit processors. An x32 process gets access to the
2222 full 64-bit register file and wide data path while leaving
2223 pointers at 32 bits for smaller memory footprint.
2225 You will need a recent binutils (2.22 or later) with
2226 elf32_x86_64 support enabled to compile a kernel with this
2231 depends on IA32_EMULATION || X86_X32
2232 select ARCH_WANT_OLD_COMPAT_IPC
2235 config COMPAT_FOR_U64_ALIGNMENT
2238 config SYSVIPC_COMPAT
2250 config HAVE_ATOMIC_IOMAP
2254 config HAVE_TEXT_POKE_SMP
2256 select STOP_MACHINE if SMP
2258 config X86_DEV_DMA_OPS
2260 depends on X86_64 || STA2X11
2262 config X86_DMA_REMAP
2266 source "net/Kconfig"
2268 source "drivers/Kconfig"
2270 source "drivers/firmware/Kconfig"
2274 source "arch/x86/Kconfig.debug"
2276 source "security/Kconfig"
2278 source "crypto/Kconfig"
2280 source "arch/x86/kvm/Kconfig"
2282 source "lib/Kconfig"