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
18 select X86_DEV_DMA_OPS
23 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PCSPKR_PLATFORM
28 select HAVE_PERF_EVENTS
30 select HAVE_IOREMAP_PROT
33 select HAVE_MEMBLOCK_NODE_MAP
34 select ARCH_DISCARD_MEMBLOCK
35 select ARCH_WANT_OPTIONAL_GPIOLIB
36 select ARCH_WANT_FRAME_POINTERS
38 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
39 select HAVE_KRETPROBES
41 select HAVE_FTRACE_MCOUNT_RECORD
42 select HAVE_FENTRY if X86_64
43 select HAVE_C_RECORDMCOUNT
44 select HAVE_DYNAMIC_FTRACE
45 select HAVE_FUNCTION_TRACER
46 select HAVE_FUNCTION_GRAPH_TRACER
47 select HAVE_FUNCTION_GRAPH_FP_TEST
48 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
49 select HAVE_SYSCALL_TRACEPOINTS
50 select SYSCTL_EXCEPTION_TRACE
53 select HAVE_ARCH_TRACEHOOK
54 select HAVE_GENERIC_DMA_COHERENT if X86_32
55 select HAVE_EFFICIENT_UNALIGNED_ACCESS
56 select USER_STACKTRACE_SUPPORT
57 select HAVE_REGS_AND_STACK_ACCESS_API
58 select HAVE_DMA_API_DEBUG
59 select HAVE_KERNEL_GZIP
60 select HAVE_KERNEL_BZIP2
61 select HAVE_KERNEL_LZMA
63 select HAVE_KERNEL_LZO
64 select HAVE_HW_BREAKPOINT
65 select HAVE_MIXED_BREAKPOINTS_REGS
67 select HAVE_PERF_EVENTS_NMI
69 select HAVE_PERF_USER_STACK_DUMP
70 select HAVE_DEBUG_KMEMLEAK
72 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
73 select HAVE_CMPXCHG_LOCAL if !M386
74 select HAVE_CMPXCHG_DOUBLE
75 select HAVE_ARCH_KMEMCHECK
76 select HAVE_USER_RETURN_NOTIFIER
77 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
78 select HAVE_ARCH_JUMP_LABEL
79 select HAVE_TEXT_POKE_SMP
80 select HAVE_GENERIC_HARDIRQS
81 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
83 select GENERIC_FIND_FIRST_BIT
84 select GENERIC_IRQ_PROBE
85 select GENERIC_PENDING_IRQ if SMP
86 select GENERIC_IRQ_SHOW
87 select GENERIC_CLOCKEVENTS_MIN_ADJUST
88 select IRQ_FORCED_THREADING
89 select USE_GENERIC_SMP_HELPERS if SMP
90 select HAVE_BPF_JIT if X86_64
91 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
93 select ARCH_HAVE_NMI_SAFE_CMPXCHG
95 select DCACHE_WORD_ACCESS
96 select GENERIC_SMP_IDLE_THREAD
97 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
98 select HAVE_ARCH_SECCOMP_FILTER
99 select BUILDTIME_EXTABLE_SORT
100 select GENERIC_CMOS_UPDATE
101 select CLOCKSOURCE_WATCHDOG
102 select GENERIC_CLOCKEVENTS
103 select ARCH_CLOCKSOURCE_DATA if X86_64
104 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
105 select GENERIC_TIME_VSYSCALL if X86_64
106 select KTIME_SCALAR if X86_32
107 select GENERIC_STRNCPY_FROM_USER
108 select GENERIC_STRNLEN_USER
109 select HAVE_RCU_USER_QS if X86_64
110 select HAVE_IRQ_TIME_ACCOUNTING
111 select ALWAYS_USE_PERSISTENT_CLOCK
112 select GENERIC_KERNEL_THREAD
113 select GENERIC_KERNEL_EXECVE
114 select MODULES_USE_ELF_REL if X86_32
115 select MODULES_USE_ELF_RELA if X86_64
117 config INSTRUCTION_DECODER
119 depends on KPROBES || PERF_EVENTS || UPROBES
123 default "elf32-i386" if X86_32
124 default "elf64-x86-64" if X86_64
126 config ARCH_DEFCONFIG
128 default "arch/x86/configs/i386_defconfig" if X86_32
129 default "arch/x86/configs/x86_64_defconfig" if X86_64
131 config LOCKDEP_SUPPORT
134 config STACKTRACE_SUPPORT
137 config HAVE_LATENCYTOP_SUPPORT
146 config NEED_DMA_MAP_STATE
148 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
150 config NEED_SG_DMA_LENGTH
153 config GENERIC_ISA_DMA
155 depends on ISA_DMA_API
160 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
162 config GENERIC_BUG_RELATIVE_POINTERS
165 config GENERIC_HWEIGHT
171 config ARCH_MAY_HAVE_PC_FDC
173 depends on ISA_DMA_API
175 config RWSEM_GENERIC_SPINLOCK
179 config RWSEM_XCHGADD_ALGORITHM
183 config GENERIC_CALIBRATE_DELAY
186 config ARCH_HAS_CPU_RELAX
189 config ARCH_HAS_DEFAULT_IDLE
192 config ARCH_HAS_CACHE_LINE_SIZE
195 config ARCH_HAS_CPU_AUTOPROBE
198 config HAVE_SETUP_PER_CPU_AREA
201 config NEED_PER_CPU_EMBED_FIRST_CHUNK
204 config NEED_PER_CPU_PAGE_FIRST_CHUNK
207 config ARCH_HIBERNATION_POSSIBLE
210 config ARCH_SUSPEND_POSSIBLE
221 config ARCH_SUPPORTS_OPTIMIZED_INLINING
224 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
227 config HAVE_INTEL_TXT
229 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
233 depends on X86_32 && SMP
237 depends on X86_64 && SMP
243 config X86_32_LAZY_GS
245 depends on X86_32 && !CC_STACKPROTECTOR
247 config ARCH_HWEIGHT_CFLAGS
249 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
250 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
252 config ARCH_CPU_PROBE_RELEASE
254 depends on HOTPLUG_CPU
256 config ARCH_SUPPORTS_UPROBES
259 source "init/Kconfig"
260 source "kernel/Kconfig.freezer"
262 menu "Processor type and features"
265 bool "DMA memory allocation support" if EXPERT
268 DMA memory allocation support allows devices with less than 32-bit
269 addressing to allocate within the first 16MB of address space.
270 Disable if no such devices will be used.
275 bool "Symmetric multi-processing support"
277 This enables support for systems with more than one CPU. If you have
278 a system with only one CPU, like most personal computers, say N. If
279 you have a system with more than one CPU, say Y.
281 If you say N here, the kernel will run on single and multiprocessor
282 machines, but will use only one CPU of a multiprocessor machine. If
283 you say Y here, the kernel will run on many, but not all,
284 singleprocessor machines. On a singleprocessor machine, the kernel
285 will run faster if you say N here.
287 Note that if you say Y here and choose architecture "586" or
288 "Pentium" under "Processor family", the kernel will not work on 486
289 architectures. Similarly, multiprocessor kernels for the "PPro"
290 architecture may not work on all Pentium based boards.
292 People using multiprocessor machines who say Y here should also say
293 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
294 Management" code will be disabled if you say Y here.
296 See also <file:Documentation/x86/i386/IO-APIC.txt>,
297 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
298 <http://www.tldp.org/docs.html#howto>.
300 If you don't know what to do here, say N.
303 bool "Support x2apic"
304 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
306 This enables x2apic support on CPUs that have this feature.
308 This allows 32-bit apic IDs (so it can support very large systems),
309 and accesses the local apic via MSRs not via mmio.
311 If you don't know what to do here, say N.
314 bool "Enable MPS table" if ACPI
316 depends on X86_LOCAL_APIC
318 For old smp systems that do not have proper acpi support. Newer systems
319 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
322 bool "Support for big SMP systems with more than 8 CPUs"
323 depends on X86_32 && SMP
325 This option is needed for the systems that have more than 8 CPUs
328 config X86_EXTENDED_PLATFORM
329 bool "Support for extended (non-PC) x86 platforms"
332 If you disable this option then the kernel will only support
333 standard PC platforms. (which covers the vast majority of
336 If you enable this option then you'll be able to select support
337 for the following (non-PC) 32 bit x86 platforms:
341 SGI 320/540 (Visual Workstation)
342 STA2X11-based (e.g. Northville)
343 Summit/EXA (IBM x440)
344 Unisys ES7000 IA32 series
345 Moorestown MID devices
347 If you have one of these systems, or if you want to build a
348 generic distribution kernel, say Y here - otherwise say N.
352 config X86_EXTENDED_PLATFORM
353 bool "Support for extended (non-PC) x86 platforms"
356 If you disable this option then the kernel will only support
357 standard PC platforms. (which covers the vast majority of
360 If you enable this option then you'll be able to select support
361 for the following (non-PC) 64 bit x86 platforms:
366 If you have one of these systems, or if you want to build a
367 generic distribution kernel, say Y here - otherwise say N.
369 # This is an alphabetically sorted list of 64 bit extended platforms
370 # Please maintain the alphabetic order if and when there are additions
372 bool "Numascale NumaChip"
374 depends on X86_EXTENDED_PLATFORM
377 depends on X86_X2APIC
379 Adds support for Numascale NumaChip large-SMP systems. Needed to
380 enable more than ~168 cores.
381 If you don't have one of these, you should say N here.
385 select PARAVIRT_GUEST
387 depends on X86_64 && PCI
388 depends on X86_EXTENDED_PLATFORM
391 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
392 supposed to run on these EM64T-based machines. Only choose this option
393 if you have one of these machines.
396 bool "SGI Ultraviolet"
398 depends on X86_EXTENDED_PLATFORM
400 depends on X86_X2APIC
402 This option is needed in order to support SGI Ultraviolet systems.
403 If you don't have one of these, you should say N here.
405 # Following is an alphabetically sorted list of 32 bit extended platforms
406 # Please maintain the alphabetic order if and when there are additions
409 bool "CE4100 TV platform"
411 depends on PCI_GODIRECT
413 depends on X86_EXTENDED_PLATFORM
414 select X86_REBOOTFIXUPS
416 select OF_EARLY_FLATTREE
419 Select for the Intel CE media processor (CE4100) SOC.
420 This option compiles in support for the CE4100 SOC for settop
421 boxes and media devices.
423 config X86_WANT_INTEL_MID
424 bool "Intel MID platform support"
426 depends on X86_EXTENDED_PLATFORM
428 Select to build a kernel capable of supporting Intel MID platform
429 systems which do not have the PCI legacy interfaces (Moorestown,
430 Medfield). If you are building for a PC class system say N here.
432 if X86_WANT_INTEL_MID
438 bool "Medfield MID platform"
441 depends on X86_IO_APIC
449 select X86_PLATFORM_DEVICES
450 select MFD_INTEL_MSIC
452 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
453 Internet Device(MID) platform.
454 Unlike standard x86 PCs, Medfield does not have many legacy devices
455 nor standard legacy replacement devices/features. e.g. Medfield does
456 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
461 bool "RDC R-321x SoC"
463 depends on X86_EXTENDED_PLATFORM
465 select X86_REBOOTFIXUPS
467 This option is needed for RDC R-321x system-on-chip, also known
469 If you don't have one of these chips, you should say N here.
471 config X86_32_NON_STANDARD
472 bool "Support non-standard 32-bit SMP architectures"
473 depends on X86_32 && SMP
474 depends on X86_EXTENDED_PLATFORM
476 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
477 STA2X11, default subarchitectures. It is intended for a generic
478 binary kernel. If you select them all, kernel will probe it
479 one by one and will fallback to default.
481 # Alphabetically sorted list of Non standard 32 bit platforms
484 bool "NUMAQ (IBM/Sequent)"
485 depends on X86_32_NON_STANDARD
490 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
491 NUMA multiquad box. This changes the way that processors are
492 bootstrapped, and uses Clustered Logical APIC addressing mode instead
493 of Flat Logical. You will need a new lynxer.elf file to flash your
494 firmware with - send email to <Martin.Bligh@us.ibm.com>.
496 config X86_SUPPORTS_MEMORY_FAILURE
498 # MCE code calls memory_failure():
500 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
501 depends on !X86_NUMAQ
502 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
503 depends on X86_64 || !SPARSEMEM
504 select ARCH_SUPPORTS_MEMORY_FAILURE
507 bool "SGI 320/540 (Visual Workstation)"
508 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
509 depends on X86_32_NON_STANDARD
511 The SGI Visual Workstation series is an IA32-based workstation
512 based on SGI systems chips with some legacy PC hardware attached.
514 Say Y here to create a kernel to run on the SGI 320 or 540.
516 A kernel compiled for the Visual Workstation will run on general
517 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
520 bool "STA2X11 Companion Chip Support"
521 depends on X86_32_NON_STANDARD && PCI
522 select X86_DEV_DMA_OPS
526 select ARCH_REQUIRE_GPIOLIB
529 This adds support for boards based on the STA2X11 IO-Hub,
530 a.k.a. "ConneXt". The chip is used in place of the standard
531 PC chipset, so all "standard" peripherals are missing. If this
532 option is selected the kernel will still be able to boot on
533 standard PC machines.
536 bool "Summit/EXA (IBM x440)"
537 depends on X86_32_NON_STANDARD
539 This option is needed for IBM systems that use the Summit/EXA chipset.
540 In particular, it is needed for the x440.
543 bool "Unisys ES7000 IA32 series"
544 depends on X86_32_NON_STANDARD && X86_BIGSMP
546 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
547 supposed to run on an IA32-based Unisys ES7000 system.
550 tristate "Eurobraille/Iris poweroff module"
553 The Iris machines from EuroBraille do not have APM or ACPI support
554 to shut themselves down properly. A special I/O sequence is
555 needed to do so, which is what this module does at
558 This is only for Iris machines from EuroBraille.
562 config SCHED_OMIT_FRAME_POINTER
564 prompt "Single-depth WCHAN output"
567 Calculate simpler /proc/<PID>/wchan values. If this option
568 is disabled then wchan values will recurse back to the
569 caller function. This provides more accurate wchan values,
570 at the expense of slightly more scheduling overhead.
572 If in doubt, say "Y".
574 menuconfig PARAVIRT_GUEST
575 bool "Paravirtualized guest support"
577 Say Y here to get to see options related to running Linux under
578 various hypervisors. This option alone does not add any kernel code.
580 If you say N, all options in this submenu will be skipped and disabled.
584 config PARAVIRT_TIME_ACCOUNTING
585 bool "Paravirtual steal time accounting"
589 Select this option to enable fine granularity task steal time
590 accounting. Time spent executing other tasks in parallel with
591 the current vCPU is discounted from the vCPU power. To account for
592 that, there can be a small performance impact.
594 If in doubt, say N here.
596 source "arch/x86/xen/Kconfig"
599 bool "KVM Guest support (including kvmclock)"
602 select PARAVIRT_CLOCK
603 default y if PARAVIRT_GUEST
605 This option enables various optimizations for running under the KVM
606 hypervisor. It includes a paravirtualized clock, so that instead
607 of relying on a PIT (or probably other) emulation by the
608 underlying device model, the host provides the guest with
609 timing infrastructure such as time of day, and system time
611 source "arch/x86/lguest/Kconfig"
614 bool "Enable paravirtualization code"
616 This changes the kernel so it can modify itself when it is run
617 under a hypervisor, potentially improving performance significantly
618 over full virtualization. However, when run without a hypervisor
619 the kernel is theoretically slower and slightly larger.
621 config PARAVIRT_SPINLOCKS
622 bool "Paravirtualization layer for spinlocks"
623 depends on PARAVIRT && SMP && EXPERIMENTAL
625 Paravirtualized spinlocks allow a pvops backend to replace the
626 spinlock implementation with something virtualization-friendly
627 (for example, block the virtual CPU rather than spinning).
629 Unfortunately the downside is an up to 5% performance hit on
630 native kernels, with various workloads.
632 If you are unsure how to answer this question, answer N.
634 config PARAVIRT_CLOCK
639 config PARAVIRT_DEBUG
640 bool "paravirt-ops debugging"
641 depends on PARAVIRT && DEBUG_KERNEL
643 Enable to debug paravirt_ops internals. Specifically, BUG if
644 a paravirt_op is missing when it is called.
652 This option adds a kernel parameter 'memtest', which allows memtest
654 memtest=0, mean disabled; -- default
655 memtest=1, mean do 1 test pattern;
657 memtest=4, mean do 4 test patterns.
658 If you are unsure how to answer this question, answer N.
660 config X86_SUMMIT_NUMA
662 depends on X86_32 && NUMA && X86_32_NON_STANDARD
664 config X86_CYCLONE_TIMER
666 depends on X86_SUMMIT
668 source "arch/x86/Kconfig.cpu"
672 prompt "HPET Timer Support" if X86_32
674 Use the IA-PC HPET (High Precision Event Timer) to manage
675 time in preference to the PIT and RTC, if a HPET is
677 HPET is the next generation timer replacing legacy 8254s.
678 The HPET provides a stable time base on SMP
679 systems, unlike the TSC, but it is more expensive to access,
680 as it is off-chip. You can find the HPET spec at
681 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
683 You can safely choose Y here. However, HPET will only be
684 activated if the platform and the BIOS support this feature.
685 Otherwise the 8254 will be used for timing services.
687 Choose N to continue using the legacy 8254 timer.
689 config HPET_EMULATE_RTC
691 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
694 def_bool y if X86_INTEL_MID
695 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
697 depends on X86_INTEL_MID && SFI
699 APB timer is the replacement for 8254, HPET on X86 MID platforms.
700 The APBT provides a stable time base on SMP
701 systems, unlike the TSC, but it is more expensive to access,
702 as it is off-chip. APB timers are always running regardless of CPU
703 C states, they are used as per CPU clockevent device when possible.
705 # Mark as expert because too many people got it wrong.
706 # The code disables itself when not needed.
709 bool "Enable DMI scanning" if EXPERT
711 Enabled scanning of DMI to identify machine quirks. Say Y
712 here unless you have verified that your setup is not
713 affected by entries in the DMI blacklist. Required by PNP
717 bool "GART IOMMU support" if EXPERT
720 depends on X86_64 && PCI && AMD_NB
722 Support for full DMA access of devices with 32bit memory access only
723 on systems with more than 3GB. This is usually needed for USB,
724 sound, many IDE/SATA chipsets and some other devices.
725 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
726 based hardware IOMMU and a software bounce buffer based IOMMU used
727 on Intel systems and as fallback.
728 The code is only active when needed (enough memory and limited
729 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
733 bool "IBM Calgary IOMMU support"
735 depends on X86_64 && PCI && EXPERIMENTAL
737 Support for hardware IOMMUs in IBM's xSeries x366 and x460
738 systems. Needed to run systems with more than 3GB of memory
739 properly with 32-bit PCI devices that do not support DAC
740 (Double Address Cycle). Calgary also supports bus level
741 isolation, where all DMAs pass through the IOMMU. This
742 prevents them from going anywhere except their intended
743 destination. This catches hard-to-find kernel bugs and
744 mis-behaving drivers and devices that do not use the DMA-API
745 properly to set up their DMA buffers. The IOMMU can be
746 turned off at boot time with the iommu=off parameter.
747 Normally the kernel will make the right choice by itself.
750 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
752 prompt "Should Calgary be enabled by default?"
753 depends on CALGARY_IOMMU
755 Should Calgary be enabled by default? if you choose 'y', Calgary
756 will be used (if it exists). If you choose 'n', Calgary will not be
757 used even if it exists. If you choose 'n' and would like to use
758 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
761 # need this always selected by IOMMU for the VIA workaround
765 Support for software bounce buffers used on x86-64 systems
766 which don't have a hardware IOMMU. Using this PCI devices
767 which can only access 32-bits of memory can be used on systems
768 with more than 3 GB of memory.
773 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
776 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
777 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
778 select CPUMASK_OFFSTACK
780 Enable maximum number of CPUS and NUMA Nodes for this architecture.
784 int "Maximum number of CPUs" if SMP && !MAXSMP
785 range 2 8 if SMP && X86_32 && !X86_BIGSMP
786 range 2 512 if SMP && !MAXSMP
788 default "4096" if MAXSMP
789 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
792 This allows you to specify the maximum number of CPUs which this
793 kernel will support. The maximum supported value is 512 and the
794 minimum value which makes sense is 2.
796 This is purely to save memory - each supported CPU adds
797 approximately eight kilobytes to the kernel image.
800 bool "SMT (Hyperthreading) scheduler support"
803 SMT scheduler support improves the CPU scheduler's decision making
804 when dealing with Intel Pentium 4 chips with HyperThreading at a
805 cost of slightly increased overhead in some places. If unsure say
810 prompt "Multi-core scheduler support"
813 Multi-core scheduler support improves the CPU scheduler's decision
814 making when dealing with multi-core CPU chips at a cost of slightly
815 increased overhead in some places. If unsure say N here.
817 source "kernel/Kconfig.preempt"
820 bool "Local APIC support on uniprocessors"
821 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
823 A local APIC (Advanced Programmable Interrupt Controller) is an
824 integrated interrupt controller in the CPU. If you have a single-CPU
825 system which has a processor with a local APIC, you can say Y here to
826 enable and use it. If you say Y here even though your machine doesn't
827 have a local APIC, then the kernel will still run with no slowdown at
828 all. The local APIC supports CPU-generated self-interrupts (timer,
829 performance counters), and the NMI watchdog which detects hard
833 bool "IO-APIC support on uniprocessors"
834 depends on X86_UP_APIC
836 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
837 SMP-capable replacement for PC-style interrupt controllers. Most
838 SMP systems and many recent uniprocessor systems have one.
840 If you have a single-CPU system with an IO-APIC, you can say Y here
841 to use it. If you say Y here even though your machine doesn't have
842 an IO-APIC, then the kernel will still run with no slowdown at all.
844 config X86_LOCAL_APIC
846 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
850 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
852 config X86_VISWS_APIC
854 depends on X86_32 && X86_VISWS
856 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
857 bool "Reroute for broken boot IRQs"
858 depends on X86_IO_APIC
860 This option enables a workaround that fixes a source of
861 spurious interrupts. This is recommended when threaded
862 interrupt handling is used on systems where the generation of
863 superfluous "boot interrupts" cannot be disabled.
865 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
866 entry in the chipset's IO-APIC is masked (as, e.g. the RT
867 kernel does during interrupt handling). On chipsets where this
868 boot IRQ generation cannot be disabled, this workaround keeps
869 the original IRQ line masked so that only the equivalent "boot
870 IRQ" is delivered to the CPUs. The workaround also tells the
871 kernel to set up the IRQ handler on the boot IRQ line. In this
872 way only one interrupt is delivered to the kernel. Otherwise
873 the spurious second interrupt may cause the kernel to bring
874 down (vital) interrupt lines.
876 Only affects "broken" chipsets. Interrupt sharing may be
877 increased on these systems.
880 bool "Machine Check / overheating reporting"
883 Machine Check support allows the processor to notify the
884 kernel if it detects a problem (e.g. overheating, data corruption).
885 The action the kernel takes depends on the severity of the problem,
886 ranging from warning messages to halting the machine.
890 prompt "Intel MCE features"
891 depends on X86_MCE && X86_LOCAL_APIC
893 Additional support for intel specific MCE features such as
898 prompt "AMD MCE features"
899 depends on X86_MCE && X86_LOCAL_APIC
901 Additional support for AMD specific MCE features such as
902 the DRAM Error Threshold.
904 config X86_ANCIENT_MCE
905 bool "Support for old Pentium 5 / WinChip machine checks"
906 depends on X86_32 && X86_MCE
908 Include support for machine check handling on old Pentium 5 or WinChip
909 systems. These typically need to be enabled explicitely on the command
912 config X86_MCE_THRESHOLD
913 depends on X86_MCE_AMD || X86_MCE_INTEL
916 config X86_MCE_INJECT
918 tristate "Machine check injector support"
920 Provide support for injecting machine checks for testing purposes.
921 If you don't know what a machine check is and you don't do kernel
922 QA it is safe to say n.
924 config X86_THERMAL_VECTOR
926 depends on X86_MCE_INTEL
929 bool "Enable VM86 support" if EXPERT
933 This option is required by programs like DOSEMU to run 16-bit legacy
934 code on X86 processors. It also may be needed by software like
935 XFree86 to initialize some video cards via BIOS. Disabling this
936 option saves about 6k.
939 tristate "Toshiba Laptop support"
942 This adds a driver to safely access the System Management Mode of
943 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
944 not work on models with a Phoenix BIOS. The System Management Mode
945 is used to set the BIOS and power saving options on Toshiba portables.
947 For information on utilities to make use of this driver see the
948 Toshiba Linux utilities web site at:
949 <http://www.buzzard.org.uk/toshiba/>.
951 Say Y if you intend to run this kernel on a Toshiba portable.
955 tristate "Dell laptop support"
958 This adds a driver to safely access the System Management Mode
959 of the CPU on the Dell Inspiron 8000. The System Management Mode
960 is used to read cpu temperature and cooling fan status and to
961 control the fans on the I8K portables.
963 This driver has been tested only on the Inspiron 8000 but it may
964 also work with other Dell laptops. You can force loading on other
965 models by passing the parameter `force=1' to the module. Use at
968 For information on utilities to make use of this driver see the
969 I8K Linux utilities web site at:
970 <http://people.debian.org/~dz/i8k/>
972 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
975 config X86_REBOOTFIXUPS
976 bool "Enable X86 board specific fixups for reboot"
979 This enables chipset and/or board specific fixups to be done
980 in order to get reboot to work correctly. This is only needed on
981 some combinations of hardware and BIOS. The symptom, for which
982 this config is intended, is when reboot ends with a stalled/hung
985 Currently, the only fixup is for the Geode machines using
986 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
988 Say Y if you want to enable the fixup. Currently, it's safe to
989 enable this option even if you don't need it.
993 tristate "CPU microcode loading support"
997 If you say Y here, you will be able to update the microcode on
998 certain Intel and AMD processors. The Intel support is for the
999 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1000 Xeon etc. The AMD support is for families 0x10 and later. You will
1001 obviously need the actual microcode binary data itself which is not
1002 shipped with the Linux kernel.
1004 This option selects the general module only, you need to select
1005 at least one vendor specific module as well.
1007 To compile this driver as a module, choose M here: the module
1008 will be called microcode.
1010 config MICROCODE_INTEL
1011 bool "Intel microcode loading support"
1012 depends on MICROCODE
1016 This options enables microcode patch loading support for Intel
1019 For latest news and information on obtaining all the required
1020 Intel ingredients for this driver, check:
1021 <http://www.urbanmyth.org/microcode/>.
1023 config MICROCODE_AMD
1024 bool "AMD microcode loading support"
1025 depends on MICROCODE
1028 If you select this option, microcode patch loading support for AMD
1029 processors will be enabled.
1031 config MICROCODE_OLD_INTERFACE
1033 depends on MICROCODE
1036 tristate "/dev/cpu/*/msr - Model-specific register support"
1038 This device gives privileged processes access to the x86
1039 Model-Specific Registers (MSRs). It is a character device with
1040 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1041 MSR accesses are directed to a specific CPU on multi-processor
1045 tristate "/dev/cpu/*/cpuid - CPU information support"
1047 This device gives processes access to the x86 CPUID instruction to
1048 be executed on a specific processor. It is a character device
1049 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1053 prompt "High Memory Support"
1054 default HIGHMEM64G if X86_NUMAQ
1060 depends on !X86_NUMAQ
1062 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1063 However, the address space of 32-bit x86 processors is only 4
1064 Gigabytes large. That means that, if you have a large amount of
1065 physical memory, not all of it can be "permanently mapped" by the
1066 kernel. The physical memory that's not permanently mapped is called
1069 If you are compiling a kernel which will never run on a machine with
1070 more than 1 Gigabyte total physical RAM, answer "off" here (default
1071 choice and suitable for most users). This will result in a "3GB/1GB"
1072 split: 3GB are mapped so that each process sees a 3GB virtual memory
1073 space and the remaining part of the 4GB virtual memory space is used
1074 by the kernel to permanently map as much physical memory as
1077 If the machine has between 1 and 4 Gigabytes physical RAM, then
1080 If more than 4 Gigabytes is used then answer "64GB" here. This
1081 selection turns Intel PAE (Physical Address Extension) mode on.
1082 PAE implements 3-level paging on IA32 processors. PAE is fully
1083 supported by Linux, PAE mode is implemented on all recent Intel
1084 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1085 then the kernel will not boot on CPUs that don't support PAE!
1087 The actual amount of total physical memory will either be
1088 auto detected or can be forced by using a kernel command line option
1089 such as "mem=256M". (Try "man bootparam" or see the documentation of
1090 your boot loader (lilo or loadlin) about how to pass options to the
1091 kernel at boot time.)
1093 If unsure, say "off".
1097 depends on !X86_NUMAQ
1099 Select this if you have a 32-bit processor and between 1 and 4
1100 gigabytes of physical RAM.
1104 depends on !M386 && !M486
1107 Select this if you have a 32-bit processor and more than 4
1108 gigabytes of physical RAM.
1113 depends on EXPERIMENTAL
1114 prompt "Memory split" if EXPERT
1118 Select the desired split between kernel and user memory.
1120 If the address range available to the kernel is less than the
1121 physical memory installed, the remaining memory will be available
1122 as "high memory". Accessing high memory is a little more costly
1123 than low memory, as it needs to be mapped into the kernel first.
1124 Note that increasing the kernel address space limits the range
1125 available to user programs, making the address space there
1126 tighter. Selecting anything other than the default 3G/1G split
1127 will also likely make your kernel incompatible with binary-only
1130 If you are not absolutely sure what you are doing, leave this
1134 bool "3G/1G user/kernel split"
1135 config VMSPLIT_3G_OPT
1137 bool "3G/1G user/kernel split (for full 1G low memory)"
1139 bool "2G/2G user/kernel split"
1140 config VMSPLIT_2G_OPT
1142 bool "2G/2G user/kernel split (for full 2G low memory)"
1144 bool "1G/3G user/kernel split"
1149 default 0xB0000000 if VMSPLIT_3G_OPT
1150 default 0x80000000 if VMSPLIT_2G
1151 default 0x78000000 if VMSPLIT_2G_OPT
1152 default 0x40000000 if VMSPLIT_1G
1158 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1161 bool "PAE (Physical Address Extension) Support"
1162 depends on X86_32 && !HIGHMEM4G
1164 PAE is required for NX support, and furthermore enables
1165 larger swapspace support for non-overcommit purposes. It
1166 has the cost of more pagetable lookup overhead, and also
1167 consumes more pagetable space per process.
1169 config ARCH_PHYS_ADDR_T_64BIT
1171 depends on X86_64 || X86_PAE
1173 config ARCH_DMA_ADDR_T_64BIT
1175 depends on X86_64 || HIGHMEM64G
1177 config DIRECT_GBPAGES
1178 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1182 Allow the kernel linear mapping to use 1GB pages on CPUs that
1183 support it. This can improve the kernel's performance a tiny bit by
1184 reducing TLB pressure. If in doubt, say "Y".
1186 # Common NUMA Features
1188 bool "Numa Memory Allocation and Scheduler Support"
1190 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1191 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1193 Enable NUMA (Non Uniform Memory Access) support.
1195 The kernel will try to allocate memory used by a CPU on the
1196 local memory controller of the CPU and add some more
1197 NUMA awareness to the kernel.
1199 For 64-bit this is recommended if the system is Intel Core i7
1200 (or later), AMD Opteron, or EM64T NUMA.
1202 For 32-bit this is only needed on (rare) 32-bit-only platforms
1203 that support NUMA topologies, such as NUMAQ / Summit, or if you
1204 boot a 32-bit kernel on a 64-bit NUMA platform.
1206 Otherwise, you should say N.
1208 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1209 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1213 prompt "Old style AMD Opteron NUMA detection"
1214 depends on X86_64 && NUMA && PCI
1216 Enable AMD NUMA node topology detection. You should say Y here if
1217 you have a multi processor AMD system. This uses an old method to
1218 read the NUMA configuration directly from the builtin Northbridge
1219 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1220 which also takes priority if both are compiled in.
1222 config X86_64_ACPI_NUMA
1224 prompt "ACPI NUMA detection"
1225 depends on X86_64 && NUMA && ACPI && PCI
1228 Enable ACPI SRAT based node topology detection.
1230 # Some NUMA nodes have memory ranges that span
1231 # other nodes. Even though a pfn is valid and
1232 # between a node's start and end pfns, it may not
1233 # reside on that node. See memmap_init_zone()
1235 config NODES_SPAN_OTHER_NODES
1237 depends on X86_64_ACPI_NUMA
1240 bool "NUMA emulation"
1243 Enable NUMA emulation. A flat machine will be split
1244 into virtual nodes when booted with "numa=fake=N", where N is the
1245 number of nodes. This is only useful for debugging.
1248 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1250 default "10" if MAXSMP
1251 default "6" if X86_64
1252 default "4" if X86_NUMAQ
1254 depends on NEED_MULTIPLE_NODES
1256 Specify the maximum number of NUMA Nodes available on the target
1257 system. Increases memory reserved to accommodate various tables.
1259 config HAVE_ARCH_ALLOC_REMAP
1261 depends on X86_32 && NUMA
1263 config ARCH_HAVE_MEMORY_PRESENT
1265 depends on X86_32 && DISCONTIGMEM
1267 config NEED_NODE_MEMMAP_SIZE
1269 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1271 config ARCH_FLATMEM_ENABLE
1273 depends on X86_32 && !NUMA
1275 config ARCH_DISCONTIGMEM_ENABLE
1277 depends on NUMA && X86_32
1279 config ARCH_DISCONTIGMEM_DEFAULT
1281 depends on NUMA && X86_32
1283 config ARCH_SPARSEMEM_ENABLE
1285 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1286 select SPARSEMEM_STATIC if X86_32
1287 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1289 config ARCH_SPARSEMEM_DEFAULT
1293 config ARCH_SELECT_MEMORY_MODEL
1295 depends on ARCH_SPARSEMEM_ENABLE
1297 config ARCH_MEMORY_PROBE
1299 depends on X86_64 && MEMORY_HOTPLUG
1301 config ARCH_PROC_KCORE_TEXT
1303 depends on X86_64 && PROC_KCORE
1305 config ILLEGAL_POINTER_VALUE
1308 default 0xdead000000000000 if X86_64
1313 bool "Allocate 3rd-level pagetables from highmem"
1316 The VM uses one page table entry for each page of physical memory.
1317 For systems with a lot of RAM, this can be wasteful of precious
1318 low memory. Setting this option will put user-space page table
1319 entries in high memory.
1321 config X86_CHECK_BIOS_CORRUPTION
1322 bool "Check for low memory corruption"
1324 Periodically check for memory corruption in low memory, which
1325 is suspected to be caused by BIOS. Even when enabled in the
1326 configuration, it is disabled at runtime. Enable it by
1327 setting "memory_corruption_check=1" on the kernel command
1328 line. By default it scans the low 64k of memory every 60
1329 seconds; see the memory_corruption_check_size and
1330 memory_corruption_check_period parameters in
1331 Documentation/kernel-parameters.txt to adjust this.
1333 When enabled with the default parameters, this option has
1334 almost no overhead, as it reserves a relatively small amount
1335 of memory and scans it infrequently. It both detects corruption
1336 and prevents it from affecting the running system.
1338 It is, however, intended as a diagnostic tool; if repeatable
1339 BIOS-originated corruption always affects the same memory,
1340 you can use memmap= to prevent the kernel from using that
1343 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1344 bool "Set the default setting of memory_corruption_check"
1345 depends on X86_CHECK_BIOS_CORRUPTION
1348 Set whether the default state of memory_corruption_check is
1351 config X86_RESERVE_LOW
1352 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1356 Specify the amount of low memory to reserve for the BIOS.
1358 The first page contains BIOS data structures that the kernel
1359 must not use, so that page must always be reserved.
1361 By default we reserve the first 64K of physical RAM, as a
1362 number of BIOSes are known to corrupt that memory range
1363 during events such as suspend/resume or monitor cable
1364 insertion, so it must not be used by the kernel.
1366 You can set this to 4 if you are absolutely sure that you
1367 trust the BIOS to get all its memory reservations and usages
1368 right. If you know your BIOS have problems beyond the
1369 default 64K area, you can set this to 640 to avoid using the
1370 entire low memory range.
1372 If you have doubts about the BIOS (e.g. suspend/resume does
1373 not work or there's kernel crashes after certain hardware
1374 hotplug events) then you might want to enable
1375 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1376 typical corruption patterns.
1378 Leave this to the default value of 64 if you are unsure.
1380 config MATH_EMULATION
1382 prompt "Math emulation" if X86_32
1384 Linux can emulate a math coprocessor (used for floating point
1385 operations) if you don't have one. 486DX and Pentium processors have
1386 a math coprocessor built in, 486SX and 386 do not, unless you added
1387 a 487DX or 387, respectively. (The messages during boot time can
1388 give you some hints here ["man dmesg"].) Everyone needs either a
1389 coprocessor or this emulation.
1391 If you don't have a math coprocessor, you need to say Y here; if you
1392 say Y here even though you have a coprocessor, the coprocessor will
1393 be used nevertheless. (This behavior can be changed with the kernel
1394 command line option "no387", which comes handy if your coprocessor
1395 is broken. Try "man bootparam" or see the documentation of your boot
1396 loader (lilo or loadlin) about how to pass options to the kernel at
1397 boot time.) This means that it is a good idea to say Y here if you
1398 intend to use this kernel on different machines.
1400 More information about the internals of the Linux math coprocessor
1401 emulation can be found in <file:arch/x86/math-emu/README>.
1403 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1404 kernel, it won't hurt.
1408 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1410 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1411 the Memory Type Range Registers (MTRRs) may be used to control
1412 processor access to memory ranges. This is most useful if you have
1413 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1414 allows bus write transfers to be combined into a larger transfer
1415 before bursting over the PCI/AGP bus. This can increase performance
1416 of image write operations 2.5 times or more. Saying Y here creates a
1417 /proc/mtrr file which may be used to manipulate your processor's
1418 MTRRs. Typically the X server should use this.
1420 This code has a reasonably generic interface so that similar
1421 control registers on other processors can be easily supported
1424 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1425 Registers (ARRs) which provide a similar functionality to MTRRs. For
1426 these, the ARRs are used to emulate the MTRRs.
1427 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1428 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1429 write-combining. All of these processors are supported by this code
1430 and it makes sense to say Y here if you have one of them.
1432 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1433 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1434 can lead to all sorts of problems, so it's good to say Y here.
1436 You can safely say Y even if your machine doesn't have MTRRs, you'll
1437 just add about 9 KB to your kernel.
1439 See <file:Documentation/x86/mtrr.txt> for more information.
1441 config MTRR_SANITIZER
1443 prompt "MTRR cleanup support"
1446 Convert MTRR layout from continuous to discrete, so X drivers can
1447 add writeback entries.
1449 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1450 The largest mtrr entry size for a continuous block can be set with
1455 config MTRR_SANITIZER_ENABLE_DEFAULT
1456 int "MTRR cleanup enable value (0-1)"
1459 depends on MTRR_SANITIZER
1461 Enable mtrr cleanup default value
1463 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1464 int "MTRR cleanup spare reg num (0-7)"
1467 depends on MTRR_SANITIZER
1469 mtrr cleanup spare entries default, it can be changed via
1470 mtrr_spare_reg_nr=N on the kernel command line.
1474 prompt "x86 PAT support" if EXPERT
1477 Use PAT attributes to setup page level cache control.
1479 PATs are the modern equivalents of MTRRs and are much more
1480 flexible than MTRRs.
1482 Say N here if you see bootup problems (boot crash, boot hang,
1483 spontaneous reboots) or a non-working video driver.
1487 config ARCH_USES_PG_UNCACHED
1493 prompt "x86 architectural random number generator" if EXPERT
1495 Enable the x86 architectural RDRAND instruction
1496 (Intel Bull Mountain technology) to generate random numbers.
1497 If supported, this is a high bandwidth, cryptographically
1498 secure hardware random number generator.
1502 prompt "Supervisor Mode Access Prevention" if EXPERT
1504 Supervisor Mode Access Prevention (SMAP) is a security
1505 feature in newer Intel processors. There is a small
1506 performance cost if this enabled and turned on; there is
1507 also a small increase in the kernel size if this is enabled.
1512 bool "EFI runtime service support"
1515 This enables the kernel to use EFI runtime services that are
1516 available (such as the EFI variable services).
1518 This option is only useful on systems that have EFI firmware.
1519 In addition, you should use the latest ELILO loader available
1520 at <http://elilo.sourceforge.net> in order to take advantage
1521 of EFI runtime services. However, even with this option, the
1522 resultant kernel should continue to boot on existing non-EFI
1526 bool "EFI stub support"
1529 This kernel feature allows a bzImage to be loaded directly
1530 by EFI firmware without the use of a bootloader.
1532 See Documentation/x86/efi-stub.txt for more information.
1536 prompt "Enable seccomp to safely compute untrusted bytecode"
1538 This kernel feature is useful for number crunching applications
1539 that may need to compute untrusted bytecode during their
1540 execution. By using pipes or other transports made available to
1541 the process as file descriptors supporting the read/write
1542 syscalls, it's possible to isolate those applications in
1543 their own address space using seccomp. Once seccomp is
1544 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1545 and the task is only allowed to execute a few safe syscalls
1546 defined by each seccomp mode.
1548 If unsure, say Y. Only embedded should say N here.
1550 config CC_STACKPROTECTOR
1551 bool "Enable -fstack-protector buffer overflow detection"
1553 This option turns on the -fstack-protector GCC feature. This
1554 feature puts, at the beginning of functions, a canary value on
1555 the stack just before the return address, and validates
1556 the value just before actually returning. Stack based buffer
1557 overflows (that need to overwrite this return address) now also
1558 overwrite the canary, which gets detected and the attack is then
1559 neutralized via a kernel panic.
1561 This feature requires gcc version 4.2 or above, or a distribution
1562 gcc with the feature backported. Older versions are automatically
1563 detected and for those versions, this configuration option is
1564 ignored. (and a warning is printed during bootup)
1566 source kernel/Kconfig.hz
1569 bool "kexec system call"
1571 kexec is a system call that implements the ability to shutdown your
1572 current kernel, and to start another kernel. It is like a reboot
1573 but it is independent of the system firmware. And like a reboot
1574 you can start any kernel with it, not just Linux.
1576 The name comes from the similarity to the exec system call.
1578 It is an ongoing process to be certain the hardware in a machine
1579 is properly shutdown, so do not be surprised if this code does not
1580 initially work for you. It may help to enable device hotplugging
1581 support. As of this writing the exact hardware interface is
1582 strongly in flux, so no good recommendation can be made.
1585 bool "kernel crash dumps"
1586 depends on X86_64 || (X86_32 && HIGHMEM)
1588 Generate crash dump after being started by kexec.
1589 This should be normally only set in special crash dump kernels
1590 which are loaded in the main kernel with kexec-tools into
1591 a specially reserved region and then later executed after
1592 a crash by kdump/kexec. The crash dump kernel must be compiled
1593 to a memory address not used by the main kernel or BIOS using
1594 PHYSICAL_START, or it must be built as a relocatable image
1595 (CONFIG_RELOCATABLE=y).
1596 For more details see Documentation/kdump/kdump.txt
1599 bool "kexec jump (EXPERIMENTAL)"
1600 depends on EXPERIMENTAL
1601 depends on KEXEC && HIBERNATION
1603 Jump between original kernel and kexeced kernel and invoke
1604 code in physical address mode via KEXEC
1606 config PHYSICAL_START
1607 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1610 This gives the physical address where the kernel is loaded.
1612 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1613 bzImage will decompress itself to above physical address and
1614 run from there. Otherwise, bzImage will run from the address where
1615 it has been loaded by the boot loader and will ignore above physical
1618 In normal kdump cases one does not have to set/change this option
1619 as now bzImage can be compiled as a completely relocatable image
1620 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1621 address. This option is mainly useful for the folks who don't want
1622 to use a bzImage for capturing the crash dump and want to use a
1623 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1624 to be specifically compiled to run from a specific memory area
1625 (normally a reserved region) and this option comes handy.
1627 So if you are using bzImage for capturing the crash dump,
1628 leave the value here unchanged to 0x1000000 and set
1629 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1630 for capturing the crash dump change this value to start of
1631 the reserved region. In other words, it can be set based on
1632 the "X" value as specified in the "crashkernel=YM@XM"
1633 command line boot parameter passed to the panic-ed
1634 kernel. Please take a look at Documentation/kdump/kdump.txt
1635 for more details about crash dumps.
1637 Usage of bzImage for capturing the crash dump is recommended as
1638 one does not have to build two kernels. Same kernel can be used
1639 as production kernel and capture kernel. Above option should have
1640 gone away after relocatable bzImage support is introduced. But it
1641 is present because there are users out there who continue to use
1642 vmlinux for dump capture. This option should go away down the
1645 Don't change this unless you know what you are doing.
1648 bool "Build a relocatable kernel"
1651 This builds a kernel image that retains relocation information
1652 so it can be loaded someplace besides the default 1MB.
1653 The relocations tend to make the kernel binary about 10% larger,
1654 but are discarded at runtime.
1656 One use is for the kexec on panic case where the recovery kernel
1657 must live at a different physical address than the primary
1660 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1661 it has been loaded at and the compile time physical address
1662 (CONFIG_PHYSICAL_START) is ignored.
1664 # Relocation on x86-32 needs some additional build support
1665 config X86_NEED_RELOCS
1667 depends on X86_32 && RELOCATABLE
1669 config PHYSICAL_ALIGN
1670 hex "Alignment value to which kernel should be aligned" if X86_32
1672 range 0x2000 0x1000000
1674 This value puts the alignment restrictions on physical address
1675 where kernel is loaded and run from. Kernel is compiled for an
1676 address which meets above alignment restriction.
1678 If bootloader loads the kernel at a non-aligned address and
1679 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1680 address aligned to above value and run from there.
1682 If bootloader loads the kernel at a non-aligned address and
1683 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1684 load address and decompress itself to the address it has been
1685 compiled for and run from there. The address for which kernel is
1686 compiled already meets above alignment restrictions. Hence the
1687 end result is that kernel runs from a physical address meeting
1688 above alignment restrictions.
1690 Don't change this unless you know what you are doing.
1693 bool "Support for hot-pluggable CPUs"
1694 depends on SMP && HOTPLUG
1696 Say Y here to allow turning CPUs off and on. CPUs can be
1697 controlled through /sys/devices/system/cpu.
1698 ( Note: power management support will enable this option
1699 automatically on SMP systems. )
1700 Say N if you want to disable CPU hotplug.
1704 prompt "Compat VDSO support"
1705 depends on X86_32 || IA32_EMULATION
1707 Map the 32-bit VDSO to the predictable old-style address too.
1709 Say N here if you are running a sufficiently recent glibc
1710 version (2.3.3 or later), to remove the high-mapped
1711 VDSO mapping and to exclusively use the randomized VDSO.
1716 bool "Built-in kernel command line"
1718 Allow for specifying boot arguments to the kernel at
1719 build time. On some systems (e.g. embedded ones), it is
1720 necessary or convenient to provide some or all of the
1721 kernel boot arguments with the kernel itself (that is,
1722 to not rely on the boot loader to provide them.)
1724 To compile command line arguments into the kernel,
1725 set this option to 'Y', then fill in the
1726 the boot arguments in CONFIG_CMDLINE.
1728 Systems with fully functional boot loaders (i.e. non-embedded)
1729 should leave this option set to 'N'.
1732 string "Built-in kernel command string"
1733 depends on CMDLINE_BOOL
1736 Enter arguments here that should be compiled into the kernel
1737 image and used at boot time. If the boot loader provides a
1738 command line at boot time, it is appended to this string to
1739 form the full kernel command line, when the system boots.
1741 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1742 change this behavior.
1744 In most cases, the command line (whether built-in or provided
1745 by the boot loader) should specify the device for the root
1748 config CMDLINE_OVERRIDE
1749 bool "Built-in command line overrides boot loader arguments"
1750 depends on CMDLINE_BOOL
1752 Set this option to 'Y' to have the kernel ignore the boot loader
1753 command line, and use ONLY the built-in command line.
1755 This is used to work around broken boot loaders. This should
1756 be set to 'N' under normal conditions.
1760 config ARCH_ENABLE_MEMORY_HOTPLUG
1762 depends on X86_64 || (X86_32 && HIGHMEM)
1764 config ARCH_ENABLE_MEMORY_HOTREMOVE
1766 depends on MEMORY_HOTPLUG
1768 config USE_PERCPU_NUMA_NODE_ID
1772 menu "Power management and ACPI options"
1774 config ARCH_HIBERNATION_HEADER
1776 depends on X86_64 && HIBERNATION
1778 source "kernel/power/Kconfig"
1780 source "drivers/acpi/Kconfig"
1782 source "drivers/sfi/Kconfig"
1789 tristate "APM (Advanced Power Management) BIOS support"
1790 depends on X86_32 && PM_SLEEP
1792 APM is a BIOS specification for saving power using several different
1793 techniques. This is mostly useful for battery powered laptops with
1794 APM compliant BIOSes. If you say Y here, the system time will be
1795 reset after a RESUME operation, the /proc/apm device will provide
1796 battery status information, and user-space programs will receive
1797 notification of APM "events" (e.g. battery status change).
1799 If you select "Y" here, you can disable actual use of the APM
1800 BIOS by passing the "apm=off" option to the kernel at boot time.
1802 Note that the APM support is almost completely disabled for
1803 machines with more than one CPU.
1805 In order to use APM, you will need supporting software. For location
1806 and more information, read <file:Documentation/power/apm-acpi.txt>
1807 and the Battery Powered Linux mini-HOWTO, available from
1808 <http://www.tldp.org/docs.html#howto>.
1810 This driver does not spin down disk drives (see the hdparm(8)
1811 manpage ("man 8 hdparm") for that), and it doesn't turn off
1812 VESA-compliant "green" monitors.
1814 This driver does not support the TI 4000M TravelMate and the ACER
1815 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1816 desktop machines also don't have compliant BIOSes, and this driver
1817 may cause those machines to panic during the boot phase.
1819 Generally, if you don't have a battery in your machine, there isn't
1820 much point in using this driver and you should say N. If you get
1821 random kernel OOPSes or reboots that don't seem to be related to
1822 anything, try disabling/enabling this option (or disabling/enabling
1825 Some other things you should try when experiencing seemingly random,
1828 1) make sure that you have enough swap space and that it is
1830 2) pass the "no-hlt" option to the kernel
1831 3) switch on floating point emulation in the kernel and pass
1832 the "no387" option to the kernel
1833 4) pass the "floppy=nodma" option to the kernel
1834 5) pass the "mem=4M" option to the kernel (thereby disabling
1835 all but the first 4 MB of RAM)
1836 6) make sure that the CPU is not over clocked.
1837 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1838 8) disable the cache from your BIOS settings
1839 9) install a fan for the video card or exchange video RAM
1840 10) install a better fan for the CPU
1841 11) exchange RAM chips
1842 12) exchange the motherboard.
1844 To compile this driver as a module, choose M here: the
1845 module will be called apm.
1849 config APM_IGNORE_USER_SUSPEND
1850 bool "Ignore USER SUSPEND"
1852 This option will ignore USER SUSPEND requests. On machines with a
1853 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1854 series notebooks, it is necessary to say Y because of a BIOS bug.
1856 config APM_DO_ENABLE
1857 bool "Enable PM at boot time"
1859 Enable APM features at boot time. From page 36 of the APM BIOS
1860 specification: "When disabled, the APM BIOS does not automatically
1861 power manage devices, enter the Standby State, enter the Suspend
1862 State, or take power saving steps in response to CPU Idle calls."
1863 This driver will make CPU Idle calls when Linux is idle (unless this
1864 feature is turned off -- see "Do CPU IDLE calls", below). This
1865 should always save battery power, but more complicated APM features
1866 will be dependent on your BIOS implementation. You may need to turn
1867 this option off if your computer hangs at boot time when using APM
1868 support, or if it beeps continuously instead of suspending. Turn
1869 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1870 T400CDT. This is off by default since most machines do fine without
1874 bool "Make CPU Idle calls when idle"
1876 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1877 On some machines, this can activate improved power savings, such as
1878 a slowed CPU clock rate, when the machine is idle. These idle calls
1879 are made after the idle loop has run for some length of time (e.g.,
1880 333 mS). On some machines, this will cause a hang at boot time or
1881 whenever the CPU becomes idle. (On machines with more than one CPU,
1882 this option does nothing.)
1884 config APM_DISPLAY_BLANK
1885 bool "Enable console blanking using APM"
1887 Enable console blanking using the APM. Some laptops can use this to
1888 turn off the LCD backlight when the screen blanker of the Linux
1889 virtual console blanks the screen. Note that this is only used by
1890 the virtual console screen blanker, and won't turn off the backlight
1891 when using the X Window system. This also doesn't have anything to
1892 do with your VESA-compliant power-saving monitor. Further, this
1893 option doesn't work for all laptops -- it might not turn off your
1894 backlight at all, or it might print a lot of errors to the console,
1895 especially if you are using gpm.
1897 config APM_ALLOW_INTS
1898 bool "Allow interrupts during APM BIOS calls"
1900 Normally we disable external interrupts while we are making calls to
1901 the APM BIOS as a measure to lessen the effects of a badly behaving
1902 BIOS implementation. The BIOS should reenable interrupts if it
1903 needs to. Unfortunately, some BIOSes do not -- especially those in
1904 many of the newer IBM Thinkpads. If you experience hangs when you
1905 suspend, try setting this to Y. Otherwise, say N.
1909 source "drivers/cpufreq/Kconfig"
1911 source "drivers/cpuidle/Kconfig"
1913 source "drivers/idle/Kconfig"
1918 menu "Bus options (PCI etc.)"
1923 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1925 Find out whether you have a PCI motherboard. PCI is the name of a
1926 bus system, i.e. the way the CPU talks to the other stuff inside
1927 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1928 VESA. If you have PCI, say Y, otherwise N.
1931 prompt "PCI access mode"
1932 depends on X86_32 && PCI
1935 On PCI systems, the BIOS can be used to detect the PCI devices and
1936 determine their configuration. However, some old PCI motherboards
1937 have BIOS bugs and may crash if this is done. Also, some embedded
1938 PCI-based systems don't have any BIOS at all. Linux can also try to
1939 detect the PCI hardware directly without using the BIOS.
1941 With this option, you can specify how Linux should detect the
1942 PCI devices. If you choose "BIOS", the BIOS will be used,
1943 if you choose "Direct", the BIOS won't be used, and if you
1944 choose "MMConfig", then PCI Express MMCONFIG will be used.
1945 If you choose "Any", the kernel will try MMCONFIG, then the
1946 direct access method and falls back to the BIOS if that doesn't
1947 work. If unsure, go with the default, which is "Any".
1952 config PCI_GOMMCONFIG
1969 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1971 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1974 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1978 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1982 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1986 depends on PCI && XEN
1994 bool "Support mmconfig PCI config space access"
1995 depends on X86_64 && PCI && ACPI
1997 config PCI_CNB20LE_QUIRK
1998 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1999 depends on PCI && EXPERIMENTAL
2001 Read the PCI windows out of the CNB20LE host bridge. This allows
2002 PCI hotplug to work on systems with the CNB20LE chipset which do
2005 There's no public spec for this chipset, and this functionality
2006 is known to be incomplete.
2008 You should say N unless you know you need this.
2010 source "drivers/pci/pcie/Kconfig"
2012 source "drivers/pci/Kconfig"
2014 # x86_64 have no ISA slots, but can have ISA-style DMA.
2016 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2019 Enables ISA-style DMA support for devices requiring such controllers.
2027 Find out whether you have ISA slots on your motherboard. ISA is the
2028 name of a bus system, i.e. the way the CPU talks to the other stuff
2029 inside your box. Other bus systems are PCI, EISA, MicroChannel
2030 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2031 newer boards don't support it. If you have ISA, say Y, otherwise N.
2037 The Extended Industry Standard Architecture (EISA) bus was
2038 developed as an open alternative to the IBM MicroChannel bus.
2040 The EISA bus provided some of the features of the IBM MicroChannel
2041 bus while maintaining backward compatibility with cards made for
2042 the older ISA bus. The EISA bus saw limited use between 1988 and
2043 1995 when it was made obsolete by the PCI bus.
2045 Say Y here if you are building a kernel for an EISA-based machine.
2049 source "drivers/eisa/Kconfig"
2052 tristate "NatSemi SCx200 support"
2054 This provides basic support for National Semiconductor's
2055 (now AMD's) Geode processors. The driver probes for the
2056 PCI-IDs of several on-chip devices, so its a good dependency
2057 for other scx200_* drivers.
2059 If compiled as a module, the driver is named scx200.
2061 config SCx200HR_TIMER
2062 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2066 This driver provides a clocksource built upon the on-chip
2067 27MHz high-resolution timer. Its also a workaround for
2068 NSC Geode SC-1100's buggy TSC, which loses time when the
2069 processor goes idle (as is done by the scheduler). The
2070 other workaround is idle=poll boot option.
2073 bool "One Laptop Per Child support"
2080 Add support for detecting the unique features of the OLPC
2084 bool "OLPC XO-1 Power Management"
2085 depends on OLPC && MFD_CS5535 && PM_SLEEP
2088 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2091 bool "OLPC XO-1 Real Time Clock"
2092 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2094 Add support for the XO-1 real time clock, which can be used as a
2095 programmable wakeup source.
2098 bool "OLPC XO-1 SCI extras"
2099 depends on OLPC && OLPC_XO1_PM
2104 Add support for SCI-based features of the OLPC XO-1 laptop:
2105 - EC-driven system wakeups
2109 - AC adapter status updates
2110 - Battery status updates
2112 config OLPC_XO15_SCI
2113 bool "OLPC XO-1.5 SCI extras"
2114 depends on OLPC && ACPI
2117 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2118 - EC-driven system wakeups
2119 - AC adapter status updates
2120 - Battery status updates
2123 bool "PCEngines ALIX System Support (LED setup)"
2126 This option enables system support for the PCEngines ALIX.
2127 At present this just sets up LEDs for GPIO control on
2128 ALIX2/3/6 boards. However, other system specific setup should
2131 Note: You must still enable the drivers for GPIO and LED support
2132 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2134 Note: You have to set alix.force=1 for boards with Award BIOS.
2137 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2140 This option enables system support for the Soekris Engineering net5501.
2143 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2147 This option enables system support for the Traverse Technologies GEOS.
2153 depends on CPU_SUP_AMD && PCI
2155 source "drivers/pcmcia/Kconfig"
2157 source "drivers/pci/hotplug/Kconfig"
2160 bool "RapidIO support"
2164 If you say Y here, the kernel will include drivers and
2165 infrastructure code to support RapidIO interconnect devices.
2167 source "drivers/rapidio/Kconfig"
2172 menu "Executable file formats / Emulations"
2174 source "fs/Kconfig.binfmt"
2176 config IA32_EMULATION
2177 bool "IA32 Emulation"
2179 select COMPAT_BINFMT_ELF
2182 Include code to run legacy 32-bit programs under a
2183 64-bit kernel. You should likely turn this on, unless you're
2184 100% sure that you don't have any 32-bit programs left.
2187 tristate "IA32 a.out support"
2188 depends on IA32_EMULATION
2190 Support old a.out binaries in the 32bit emulation.
2193 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2194 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2196 Include code to run binaries for the x32 native 32-bit ABI
2197 for 64-bit processors. An x32 process gets access to the
2198 full 64-bit register file and wide data path while leaving
2199 pointers at 32 bits for smaller memory footprint.
2201 You will need a recent binutils (2.22 or later) with
2202 elf32_x86_64 support enabled to compile a kernel with this
2207 depends on IA32_EMULATION || X86_X32
2208 select ARCH_WANT_OLD_COMPAT_IPC
2211 config COMPAT_FOR_U64_ALIGNMENT
2214 config SYSVIPC_COMPAT
2226 config HAVE_ATOMIC_IOMAP
2230 config HAVE_TEXT_POKE_SMP
2232 select STOP_MACHINE if SMP
2234 config X86_DEV_DMA_OPS
2236 depends on X86_64 || STA2X11
2238 config X86_DMA_REMAP
2242 source "net/Kconfig"
2244 source "drivers/Kconfig"
2246 source "drivers/firmware/Kconfig"
2250 source "arch/x86/Kconfig.debug"
2252 source "security/Kconfig"
2254 source "crypto/Kconfig"
2256 source "arch/x86/kvm/Kconfig"
2258 source "lib/Kconfig"