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
15 select X86_DEV_DMA_OPS
20 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
24 select HAVE_PCSPKR_PLATFORM
25 select HAVE_PERF_EVENTS
27 select HAVE_IOREMAP_PROT
30 select HAVE_MEMBLOCK_NODE_MAP
31 select ARCH_DISCARD_MEMBLOCK
32 select ARCH_WANT_OPTIONAL_GPIOLIB
33 select ARCH_WANT_FRAME_POINTERS
35 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
36 select HAVE_KRETPROBES
38 select HAVE_FTRACE_MCOUNT_RECORD
39 select HAVE_C_RECORDMCOUNT
40 select HAVE_DYNAMIC_FTRACE
41 select HAVE_FUNCTION_TRACER
42 select HAVE_FUNCTION_GRAPH_TRACER
43 select HAVE_FUNCTION_GRAPH_FP_TEST
44 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
45 select HAVE_SYSCALL_TRACEPOINTS
48 select HAVE_ARCH_TRACEHOOK
49 select HAVE_GENERIC_DMA_COHERENT if X86_32
50 select HAVE_EFFICIENT_UNALIGNED_ACCESS
51 select USER_STACKTRACE_SUPPORT
52 select HAVE_REGS_AND_STACK_ACCESS_API
53 select HAVE_DMA_API_DEBUG
54 select HAVE_KERNEL_GZIP
55 select HAVE_KERNEL_BZIP2
56 select HAVE_KERNEL_LZMA
58 select HAVE_KERNEL_LZO
59 select HAVE_HW_BREAKPOINT
60 select HAVE_MIXED_BREAKPOINTS_REGS
62 select HAVE_PERF_EVENTS_NMI
64 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
65 select HAVE_CMPXCHG_LOCAL if !M386
66 select HAVE_CMPXCHG_DOUBLE
67 select HAVE_ARCH_KMEMCHECK
68 select HAVE_USER_RETURN_NOTIFIER
69 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
70 select HAVE_ARCH_JUMP_LABEL
71 select HAVE_TEXT_POKE_SMP
72 select HAVE_GENERIC_HARDIRQS
73 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
75 select GENERIC_FIND_FIRST_BIT
76 select GENERIC_IRQ_PROBE
77 select GENERIC_PENDING_IRQ if SMP
78 select GENERIC_IRQ_SHOW
79 select GENERIC_CLOCKEVENTS_MIN_ADJUST
80 select IRQ_FORCED_THREADING
81 select USE_GENERIC_SMP_HELPERS if SMP
82 select HAVE_BPF_JIT if X86_64
84 select ARCH_HAVE_NMI_SAFE_CMPXCHG
86 select DCACHE_WORD_ACCESS
87 select GENERIC_SMP_IDLE_THREAD
88 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
89 select HAVE_ARCH_SECCOMP_FILTER
90 select BUILDTIME_EXTABLE_SORT
91 select GENERIC_CMOS_UPDATE
92 select CLOCKSOURCE_WATCHDOG
93 select GENERIC_CLOCKEVENTS
94 select ARCH_CLOCKSOURCE_DATA if X86_64
95 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
96 select GENERIC_TIME_VSYSCALL if X86_64
97 select KTIME_SCALAR if X86_32
98 select GENERIC_STRNCPY_FROM_USER
99 select GENERIC_STRNLEN_USER
100 select MODULES_USE_ELF_REL if X86_32
101 select MODULES_USE_ELF_RELA if X86_64
103 config INSTRUCTION_DECODER
104 def_bool (KPROBES || PERF_EVENTS || UPROBES)
108 default "elf32-i386" if X86_32
109 default "elf64-x86-64" if X86_64
111 config ARCH_DEFCONFIG
113 default "arch/x86/configs/i386_defconfig" if X86_32
114 default "arch/x86/configs/x86_64_defconfig" if X86_64
116 config LOCKDEP_SUPPORT
119 config STACKTRACE_SUPPORT
122 config HAVE_LATENCYTOP_SUPPORT
131 config NEED_DMA_MAP_STATE
132 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
134 config NEED_SG_DMA_LENGTH
137 config GENERIC_ISA_DMA
143 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
145 config GENERIC_BUG_RELATIVE_POINTERS
148 config GENERIC_HWEIGHT
154 config ARCH_MAY_HAVE_PC_FDC
157 config RWSEM_GENERIC_SPINLOCK
160 config RWSEM_XCHGADD_ALGORITHM
163 config GENERIC_CALIBRATE_DELAY
166 config ARCH_HAS_CPU_RELAX
169 config ARCH_HAS_DEFAULT_IDLE
172 config ARCH_HAS_CACHE_LINE_SIZE
175 config ARCH_HAS_CPU_AUTOPROBE
178 config HAVE_SETUP_PER_CPU_AREA
181 config NEED_PER_CPU_EMBED_FIRST_CHUNK
184 config NEED_PER_CPU_PAGE_FIRST_CHUNK
187 config ARCH_HIBERNATION_POSSIBLE
190 config ARCH_SUSPEND_POSSIBLE
201 config ARCH_SUPPORTS_OPTIMIZED_INLINING
204 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
207 config HAVE_INTEL_TXT
209 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
213 depends on X86_32 && SMP
217 depends on X86_64 && SMP
223 config X86_32_LAZY_GS
225 depends on X86_32 && !CC_STACKPROTECTOR
227 config ARCH_HWEIGHT_CFLAGS
229 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
230 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
232 config ARCH_CPU_PROBE_RELEASE
234 depends on HOTPLUG_CPU
236 config ARCH_SUPPORTS_UPROBES
239 source "init/Kconfig"
240 source "kernel/Kconfig.freezer"
242 menu "Processor type and features"
245 bool "DMA memory allocation support" if EXPERT
248 DMA memory allocation support allows devices with less than 32-bit
249 addressing to allocate within the first 16MB of address space.
250 Disable if no such devices will be used.
255 bool "Symmetric multi-processing support"
257 This enables support for systems with more than one CPU. If you have
258 a system with only one CPU, like most personal computers, say N. If
259 you have a system with more than one CPU, say Y.
261 If you say N here, the kernel will run on single and multiprocessor
262 machines, but will use only one CPU of a multiprocessor machine. If
263 you say Y here, the kernel will run on many, but not all,
264 singleprocessor machines. On a singleprocessor machine, the kernel
265 will run faster if you say N here.
267 Note that if you say Y here and choose architecture "586" or
268 "Pentium" under "Processor family", the kernel will not work on 486
269 architectures. Similarly, multiprocessor kernels for the "PPro"
270 architecture may not work on all Pentium based boards.
272 People using multiprocessor machines who say Y here should also say
273 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
274 Management" code will be disabled if you say Y here.
276 See also <file:Documentation/x86/i386/IO-APIC.txt>,
277 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
278 <http://www.tldp.org/docs.html#howto>.
280 If you don't know what to do here, say N.
283 bool "Support x2apic"
284 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
286 This enables x2apic support on CPUs that have this feature.
288 This allows 32-bit apic IDs (so it can support very large systems),
289 and accesses the local apic via MSRs not via mmio.
291 If you don't know what to do here, say N.
294 bool "Enable MPS table" if ACPI
296 depends on X86_LOCAL_APIC
298 For old smp systems that do not have proper acpi support. Newer systems
299 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
302 bool "Support for big SMP systems with more than 8 CPUs"
303 depends on X86_32 && SMP
305 This option is needed for the systems that have more than 8 CPUs
308 config X86_EXTENDED_PLATFORM
309 bool "Support for extended (non-PC) x86 platforms"
312 If you disable this option then the kernel will only support
313 standard PC platforms. (which covers the vast majority of
316 If you enable this option then you'll be able to select support
317 for the following (non-PC) 32 bit x86 platforms:
321 SGI 320/540 (Visual Workstation)
322 STA2X11-based (e.g. Northville)
323 Summit/EXA (IBM x440)
324 Unisys ES7000 IA32 series
325 Moorestown MID devices
327 If you have one of these systems, or if you want to build a
328 generic distribution kernel, say Y here - otherwise say N.
332 config X86_EXTENDED_PLATFORM
333 bool "Support for extended (non-PC) x86 platforms"
336 If you disable this option then the kernel will only support
337 standard PC platforms. (which covers the vast majority of
340 If you enable this option then you'll be able to select support
341 for the following (non-PC) 64 bit x86 platforms:
346 If you have one of these systems, or if you want to build a
347 generic distribution kernel, say Y here - otherwise say N.
349 # This is an alphabetically sorted list of 64 bit extended platforms
350 # Please maintain the alphabetic order if and when there are additions
352 bool "Numascale NumaChip"
354 depends on X86_EXTENDED_PLATFORM
357 depends on X86_X2APIC
359 Adds support for Numascale NumaChip large-SMP systems. Needed to
360 enable more than ~168 cores.
361 If you don't have one of these, you should say N here.
365 select PARAVIRT_GUEST
367 depends on X86_64 && PCI
368 depends on X86_EXTENDED_PLATFORM
371 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
372 supposed to run on these EM64T-based machines. Only choose this option
373 if you have one of these machines.
376 bool "SGI Ultraviolet"
378 depends on X86_EXTENDED_PLATFORM
380 depends on X86_X2APIC
382 This option is needed in order to support SGI Ultraviolet systems.
383 If you don't have one of these, you should say N here.
385 # Following is an alphabetically sorted list of 32 bit extended platforms
386 # Please maintain the alphabetic order if and when there are additions
389 bool "CE4100 TV platform"
391 depends on PCI_GODIRECT
393 depends on X86_EXTENDED_PLATFORM
394 select X86_REBOOTFIXUPS
396 select OF_EARLY_FLATTREE
399 Select for the Intel CE media processor (CE4100) SOC.
400 This option compiles in support for the CE4100 SOC for settop
401 boxes and media devices.
403 config X86_WANT_INTEL_MID
404 bool "Intel MID platform support"
406 depends on X86_EXTENDED_PLATFORM
408 Select to build a kernel capable of supporting Intel MID platform
409 systems which do not have the PCI legacy interfaces (Moorestown,
410 Medfield). If you are building for a PC class system say N here.
412 if X86_WANT_INTEL_MID
418 bool "Medfield MID platform"
421 depends on X86_IO_APIC
429 select X86_PLATFORM_DEVICES
430 select MFD_INTEL_MSIC
432 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
433 Internet Device(MID) platform.
434 Unlike standard x86 PCs, Medfield does not have many legacy devices
435 nor standard legacy replacement devices/features. e.g. Medfield does
436 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
441 bool "RDC R-321x SoC"
443 depends on X86_EXTENDED_PLATFORM
445 select X86_REBOOTFIXUPS
447 This option is needed for RDC R-321x system-on-chip, also known
449 If you don't have one of these chips, you should say N here.
451 config X86_32_NON_STANDARD
452 bool "Support non-standard 32-bit SMP architectures"
453 depends on X86_32 && SMP
454 depends on X86_EXTENDED_PLATFORM
456 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
457 STA2X11, default subarchitectures. It is intended for a generic
458 binary kernel. If you select them all, kernel will probe it
459 one by one and will fallback to default.
461 # Alphabetically sorted list of Non standard 32 bit platforms
464 bool "NUMAQ (IBM/Sequent)"
465 depends on X86_32_NON_STANDARD
470 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
471 NUMA multiquad box. This changes the way that processors are
472 bootstrapped, and uses Clustered Logical APIC addressing mode instead
473 of Flat Logical. You will need a new lynxer.elf file to flash your
474 firmware with - send email to <Martin.Bligh@us.ibm.com>.
476 config X86_SUPPORTS_MEMORY_FAILURE
478 # MCE code calls memory_failure():
480 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
481 depends on !X86_NUMAQ
482 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
483 depends on X86_64 || !SPARSEMEM
484 select ARCH_SUPPORTS_MEMORY_FAILURE
487 bool "SGI 320/540 (Visual Workstation)"
488 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
489 depends on X86_32_NON_STANDARD
491 The SGI Visual Workstation series is an IA32-based workstation
492 based on SGI systems chips with some legacy PC hardware attached.
494 Say Y here to create a kernel to run on the SGI 320 or 540.
496 A kernel compiled for the Visual Workstation will run on general
497 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
500 bool "STA2X11 Companion Chip Support"
501 depends on X86_32_NON_STANDARD && PCI
502 select X86_DEV_DMA_OPS
506 select ARCH_REQUIRE_GPIOLIB
509 This adds support for boards based on the STA2X11 IO-Hub,
510 a.k.a. "ConneXt". The chip is used in place of the standard
511 PC chipset, so all "standard" peripherals are missing. If this
512 option is selected the kernel will still be able to boot on
513 standard PC machines.
516 bool "Summit/EXA (IBM x440)"
517 depends on X86_32_NON_STANDARD
519 This option is needed for IBM systems that use the Summit/EXA chipset.
520 In particular, it is needed for the x440.
523 bool "Unisys ES7000 IA32 series"
524 depends on X86_32_NON_STANDARD && X86_BIGSMP
526 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
527 supposed to run on an IA32-based Unisys ES7000 system.
530 tristate "Eurobraille/Iris poweroff module"
533 The Iris machines from EuroBraille do not have APM or ACPI support
534 to shut themselves down properly. A special I/O sequence is
535 needed to do so, which is what this module does at
538 This is only for Iris machines from EuroBraille.
542 config SCHED_OMIT_FRAME_POINTER
544 prompt "Single-depth WCHAN output"
547 Calculate simpler /proc/<PID>/wchan values. If this option
548 is disabled then wchan values will recurse back to the
549 caller function. This provides more accurate wchan values,
550 at the expense of slightly more scheduling overhead.
552 If in doubt, say "Y".
554 menuconfig PARAVIRT_GUEST
555 bool "Paravirtualized guest support"
557 Say Y here to get to see options related to running Linux under
558 various hypervisors. This option alone does not add any kernel code.
560 If you say N, all options in this submenu will be skipped and disabled.
564 config PARAVIRT_TIME_ACCOUNTING
565 bool "Paravirtual steal time accounting"
569 Select this option to enable fine granularity task steal time
570 accounting. Time spent executing other tasks in parallel with
571 the current vCPU is discounted from the vCPU power. To account for
572 that, there can be a small performance impact.
574 If in doubt, say N here.
576 source "arch/x86/xen/Kconfig"
579 bool "KVM paravirtualized clock"
581 select PARAVIRT_CLOCK
583 Turning on this option will allow you to run a paravirtualized clock
584 when running over the KVM hypervisor. Instead of relying on a PIT
585 (or probably other) emulation by the underlying device model, the host
586 provides the guest with timing infrastructure such as time of day, and
590 bool "KVM Guest support"
593 This option enables various optimizations for running under the KVM
596 source "arch/x86/lguest/Kconfig"
599 bool "Enable paravirtualization code"
601 This changes the kernel so it can modify itself when it is run
602 under a hypervisor, potentially improving performance significantly
603 over full virtualization. However, when run without a hypervisor
604 the kernel is theoretically slower and slightly larger.
606 config PARAVIRT_SPINLOCKS
607 bool "Paravirtualization layer for spinlocks"
608 depends on PARAVIRT && SMP && EXPERIMENTAL
610 Paravirtualized spinlocks allow a pvops backend to replace the
611 spinlock implementation with something virtualization-friendly
612 (for example, block the virtual CPU rather than spinning).
614 Unfortunately the downside is an up to 5% performance hit on
615 native kernels, with various workloads.
617 If you are unsure how to answer this question, answer N.
619 config PARAVIRT_CLOCK
624 config PARAVIRT_DEBUG
625 bool "paravirt-ops debugging"
626 depends on PARAVIRT && DEBUG_KERNEL
628 Enable to debug paravirt_ops internals. Specifically, BUG if
629 a paravirt_op is missing when it is called.
637 This option adds a kernel parameter 'memtest', which allows memtest
639 memtest=0, mean disabled; -- default
640 memtest=1, mean do 1 test pattern;
642 memtest=4, mean do 4 test patterns.
643 If you are unsure how to answer this question, answer N.
645 config X86_SUMMIT_NUMA
647 depends on X86_32 && NUMA && X86_32_NON_STANDARD
649 config X86_CYCLONE_TIMER
651 depends on X86_SUMMIT
653 source "arch/x86/Kconfig.cpu"
657 prompt "HPET Timer Support" if X86_32
659 Use the IA-PC HPET (High Precision Event Timer) to manage
660 time in preference to the PIT and RTC, if a HPET is
662 HPET is the next generation timer replacing legacy 8254s.
663 The HPET provides a stable time base on SMP
664 systems, unlike the TSC, but it is more expensive to access,
665 as it is off-chip. You can find the HPET spec at
666 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
668 You can safely choose Y here. However, HPET will only be
669 activated if the platform and the BIOS support this feature.
670 Otherwise the 8254 will be used for timing services.
672 Choose N to continue using the legacy 8254 timer.
674 config HPET_EMULATE_RTC
676 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
679 def_bool y if X86_INTEL_MID
680 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
682 depends on X86_INTEL_MID && SFI
684 APB timer is the replacement for 8254, HPET on X86 MID platforms.
685 The APBT provides a stable time base on SMP
686 systems, unlike the TSC, but it is more expensive to access,
687 as it is off-chip. APB timers are always running regardless of CPU
688 C states, they are used as per CPU clockevent device when possible.
690 # Mark as expert because too many people got it wrong.
691 # The code disables itself when not needed.
694 bool "Enable DMI scanning" if EXPERT
696 Enabled scanning of DMI to identify machine quirks. Say Y
697 here unless you have verified that your setup is not
698 affected by entries in the DMI blacklist. Required by PNP
702 bool "GART IOMMU support" if EXPERT
705 depends on X86_64 && PCI && AMD_NB
707 Support for full DMA access of devices with 32bit memory access only
708 on systems with more than 3GB. This is usually needed for USB,
709 sound, many IDE/SATA chipsets and some other devices.
710 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
711 based hardware IOMMU and a software bounce buffer based IOMMU used
712 on Intel systems and as fallback.
713 The code is only active when needed (enough memory and limited
714 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
718 bool "IBM Calgary IOMMU support"
720 depends on X86_64 && PCI && EXPERIMENTAL
722 Support for hardware IOMMUs in IBM's xSeries x366 and x460
723 systems. Needed to run systems with more than 3GB of memory
724 properly with 32-bit PCI devices that do not support DAC
725 (Double Address Cycle). Calgary also supports bus level
726 isolation, where all DMAs pass through the IOMMU. This
727 prevents them from going anywhere except their intended
728 destination. This catches hard-to-find kernel bugs and
729 mis-behaving drivers and devices that do not use the DMA-API
730 properly to set up their DMA buffers. The IOMMU can be
731 turned off at boot time with the iommu=off parameter.
732 Normally the kernel will make the right choice by itself.
735 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
737 prompt "Should Calgary be enabled by default?"
738 depends on CALGARY_IOMMU
740 Should Calgary be enabled by default? if you choose 'y', Calgary
741 will be used (if it exists). If you choose 'n', Calgary will not be
742 used even if it exists. If you choose 'n' and would like to use
743 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
746 # need this always selected by IOMMU for the VIA workaround
750 Support for software bounce buffers used on x86-64 systems
751 which don't have a hardware IOMMU (e.g. the current generation
752 of Intel's x86-64 CPUs). Using this PCI devices which can only
753 access 32-bits of memory can be used on systems with more than
754 3 GB of memory. If unsure, say Y.
757 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
760 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
761 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
762 select CPUMASK_OFFSTACK
764 Enable maximum number of CPUS and NUMA Nodes for this architecture.
768 int "Maximum number of CPUs" if SMP && !MAXSMP
769 range 2 8 if SMP && X86_32 && !X86_BIGSMP
770 range 2 512 if SMP && !MAXSMP
772 default "4096" if MAXSMP
773 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
776 This allows you to specify the maximum number of CPUs which this
777 kernel will support. The maximum supported value is 512 and the
778 minimum value which makes sense is 2.
780 This is purely to save memory - each supported CPU adds
781 approximately eight kilobytes to the kernel image.
784 bool "SMT (Hyperthreading) scheduler support"
787 SMT scheduler support improves the CPU scheduler's decision making
788 when dealing with Intel Pentium 4 chips with HyperThreading at a
789 cost of slightly increased overhead in some places. If unsure say
794 prompt "Multi-core scheduler support"
797 Multi-core scheduler support improves the CPU scheduler's decision
798 making when dealing with multi-core CPU chips at a cost of slightly
799 increased overhead in some places. If unsure say N here.
801 config IRQ_TIME_ACCOUNTING
802 bool "Fine granularity task level IRQ time accounting"
805 Select this option to enable fine granularity task irq time
806 accounting. This is done by reading a timestamp on each
807 transitions between softirq and hardirq state, so there can be a
808 small performance impact.
810 If in doubt, say N here.
812 source "kernel/Kconfig.preempt"
815 bool "Local APIC support on uniprocessors"
816 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
818 A local APIC (Advanced Programmable Interrupt Controller) is an
819 integrated interrupt controller in the CPU. If you have a single-CPU
820 system which has a processor with a local APIC, you can say Y here to
821 enable and use it. If you say Y here even though your machine doesn't
822 have a local APIC, then the kernel will still run with no slowdown at
823 all. The local APIC supports CPU-generated self-interrupts (timer,
824 performance counters), and the NMI watchdog which detects hard
828 bool "IO-APIC support on uniprocessors"
829 depends on X86_UP_APIC
831 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
832 SMP-capable replacement for PC-style interrupt controllers. Most
833 SMP systems and many recent uniprocessor systems have one.
835 If you have a single-CPU system with an IO-APIC, you can say Y here
836 to use it. If you say Y here even though your machine doesn't have
837 an IO-APIC, then the kernel will still run with no slowdown at all.
839 config X86_LOCAL_APIC
841 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
845 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
847 config X86_VISWS_APIC
849 depends on X86_32 && X86_VISWS
851 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
852 bool "Reroute for broken boot IRQs"
853 depends on X86_IO_APIC
855 This option enables a workaround that fixes a source of
856 spurious interrupts. This is recommended when threaded
857 interrupt handling is used on systems where the generation of
858 superfluous "boot interrupts" cannot be disabled.
860 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
861 entry in the chipset's IO-APIC is masked (as, e.g. the RT
862 kernel does during interrupt handling). On chipsets where this
863 boot IRQ generation cannot be disabled, this workaround keeps
864 the original IRQ line masked so that only the equivalent "boot
865 IRQ" is delivered to the CPUs. The workaround also tells the
866 kernel to set up the IRQ handler on the boot IRQ line. In this
867 way only one interrupt is delivered to the kernel. Otherwise
868 the spurious second interrupt may cause the kernel to bring
869 down (vital) interrupt lines.
871 Only affects "broken" chipsets. Interrupt sharing may be
872 increased on these systems.
875 bool "Machine Check / overheating reporting"
877 Machine Check support allows the processor to notify the
878 kernel if it detects a problem (e.g. overheating, data corruption).
879 The action the kernel takes depends on the severity of the problem,
880 ranging from warning messages to halting the machine.
884 prompt "Intel MCE features"
885 depends on X86_MCE && X86_LOCAL_APIC
887 Additional support for intel specific MCE features such as
892 prompt "AMD MCE features"
893 depends on X86_MCE && X86_LOCAL_APIC
895 Additional support for AMD specific MCE features such as
896 the DRAM Error Threshold.
898 config X86_ANCIENT_MCE
899 bool "Support for old Pentium 5 / WinChip machine checks"
900 depends on X86_32 && X86_MCE
902 Include support for machine check handling on old Pentium 5 or WinChip
903 systems. These typically need to be enabled explicitely on the command
906 config X86_MCE_THRESHOLD
907 depends on X86_MCE_AMD || X86_MCE_INTEL
910 config X86_MCE_INJECT
912 tristate "Machine check injector support"
914 Provide support for injecting machine checks for testing purposes.
915 If you don't know what a machine check is and you don't do kernel
916 QA it is safe to say n.
918 config X86_THERMAL_VECTOR
920 depends on X86_MCE_INTEL
923 bool "Enable VM86 support" if EXPERT
927 This option is required by programs like DOSEMU to run 16-bit legacy
928 code on X86 processors. It also may be needed by software like
929 XFree86 to initialize some video cards via BIOS. Disabling this
930 option saves about 6k.
933 tristate "Toshiba Laptop support"
936 This adds a driver to safely access the System Management Mode of
937 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
938 not work on models with a Phoenix BIOS. The System Management Mode
939 is used to set the BIOS and power saving options on Toshiba portables.
941 For information on utilities to make use of this driver see the
942 Toshiba Linux utilities web site at:
943 <http://www.buzzard.org.uk/toshiba/>.
945 Say Y if you intend to run this kernel on a Toshiba portable.
949 tristate "Dell laptop support"
952 This adds a driver to safely access the System Management Mode
953 of the CPU on the Dell Inspiron 8000. The System Management Mode
954 is used to read cpu temperature and cooling fan status and to
955 control the fans on the I8K portables.
957 This driver has been tested only on the Inspiron 8000 but it may
958 also work with other Dell laptops. You can force loading on other
959 models by passing the parameter `force=1' to the module. Use at
962 For information on utilities to make use of this driver see the
963 I8K Linux utilities web site at:
964 <http://people.debian.org/~dz/i8k/>
966 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
969 config X86_REBOOTFIXUPS
970 bool "Enable X86 board specific fixups for reboot"
973 This enables chipset and/or board specific fixups to be done
974 in order to get reboot to work correctly. This is only needed on
975 some combinations of hardware and BIOS. The symptom, for which
976 this config is intended, is when reboot ends with a stalled/hung
979 Currently, the only fixup is for the Geode machines using
980 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
982 Say Y if you want to enable the fixup. Currently, it's safe to
983 enable this option even if you don't need it.
987 tristate "/dev/cpu/microcode - microcode support"
990 If you say Y here, you will be able to update the microcode on
991 certain Intel and AMD processors. The Intel support is for the
992 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
993 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
994 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
995 You will obviously need the actual microcode binary data itself
996 which is not shipped with the Linux kernel.
998 This option selects the general module only, you need to select
999 at least one vendor specific module as well.
1001 To compile this driver as a module, choose M here: the
1002 module will be called microcode.
1004 config MICROCODE_INTEL
1005 bool "Intel microcode patch loading support"
1006 depends on MICROCODE
1010 This options enables microcode patch loading support for Intel
1013 For latest news and information on obtaining all the required
1014 Intel ingredients for this driver, check:
1015 <http://www.urbanmyth.org/microcode/>.
1017 config MICROCODE_AMD
1018 bool "AMD microcode patch loading support"
1019 depends on MICROCODE
1022 If you select this option, microcode patch loading support for AMD
1023 processors will be enabled.
1025 config MICROCODE_OLD_INTERFACE
1027 depends on MICROCODE
1030 tristate "/dev/cpu/*/msr - Model-specific register support"
1032 This device gives privileged processes access to the x86
1033 Model-Specific Registers (MSRs). It is a character device with
1034 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1035 MSR accesses are directed to a specific CPU on multi-processor
1039 tristate "/dev/cpu/*/cpuid - CPU information support"
1041 This device gives processes access to the x86 CPUID instruction to
1042 be executed on a specific processor. It is a character device
1043 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1047 prompt "High Memory Support"
1048 default HIGHMEM64G if X86_NUMAQ
1054 depends on !X86_NUMAQ
1056 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1057 However, the address space of 32-bit x86 processors is only 4
1058 Gigabytes large. That means that, if you have a large amount of
1059 physical memory, not all of it can be "permanently mapped" by the
1060 kernel. The physical memory that's not permanently mapped is called
1063 If you are compiling a kernel which will never run on a machine with
1064 more than 1 Gigabyte total physical RAM, answer "off" here (default
1065 choice and suitable for most users). This will result in a "3GB/1GB"
1066 split: 3GB are mapped so that each process sees a 3GB virtual memory
1067 space and the remaining part of the 4GB virtual memory space is used
1068 by the kernel to permanently map as much physical memory as
1071 If the machine has between 1 and 4 Gigabytes physical RAM, then
1074 If more than 4 Gigabytes is used then answer "64GB" here. This
1075 selection turns Intel PAE (Physical Address Extension) mode on.
1076 PAE implements 3-level paging on IA32 processors. PAE is fully
1077 supported by Linux, PAE mode is implemented on all recent Intel
1078 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1079 then the kernel will not boot on CPUs that don't support PAE!
1081 The actual amount of total physical memory will either be
1082 auto detected or can be forced by using a kernel command line option
1083 such as "mem=256M". (Try "man bootparam" or see the documentation of
1084 your boot loader (lilo or loadlin) about how to pass options to the
1085 kernel at boot time.)
1087 If unsure, say "off".
1091 depends on !X86_NUMAQ
1093 Select this if you have a 32-bit processor and between 1 and 4
1094 gigabytes of physical RAM.
1098 depends on !M386 && !M486
1101 Select this if you have a 32-bit processor and more than 4
1102 gigabytes of physical RAM.
1107 depends on EXPERIMENTAL
1108 prompt "Memory split" if EXPERT
1112 Select the desired split between kernel and user memory.
1114 If the address range available to the kernel is less than the
1115 physical memory installed, the remaining memory will be available
1116 as "high memory". Accessing high memory is a little more costly
1117 than low memory, as it needs to be mapped into the kernel first.
1118 Note that increasing the kernel address space limits the range
1119 available to user programs, making the address space there
1120 tighter. Selecting anything other than the default 3G/1G split
1121 will also likely make your kernel incompatible with binary-only
1124 If you are not absolutely sure what you are doing, leave this
1128 bool "3G/1G user/kernel split"
1129 config VMSPLIT_3G_OPT
1131 bool "3G/1G user/kernel split (for full 1G low memory)"
1133 bool "2G/2G user/kernel split"
1134 config VMSPLIT_2G_OPT
1136 bool "2G/2G user/kernel split (for full 2G low memory)"
1138 bool "1G/3G user/kernel split"
1143 default 0xB0000000 if VMSPLIT_3G_OPT
1144 default 0x80000000 if VMSPLIT_2G
1145 default 0x78000000 if VMSPLIT_2G_OPT
1146 default 0x40000000 if VMSPLIT_1G
1152 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1155 bool "PAE (Physical Address Extension) Support"
1156 depends on X86_32 && !HIGHMEM4G
1158 PAE is required for NX support, and furthermore enables
1159 larger swapspace support for non-overcommit purposes. It
1160 has the cost of more pagetable lookup overhead, and also
1161 consumes more pagetable space per process.
1163 config ARCH_PHYS_ADDR_T_64BIT
1164 def_bool X86_64 || X86_PAE
1166 config ARCH_DMA_ADDR_T_64BIT
1167 def_bool X86_64 || HIGHMEM64G
1169 config DIRECT_GBPAGES
1170 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1174 Allow the kernel linear mapping to use 1GB pages on CPUs that
1175 support it. This can improve the kernel's performance a tiny bit by
1176 reducing TLB pressure. If in doubt, say "Y".
1178 # Common NUMA Features
1180 bool "Numa Memory Allocation and Scheduler Support"
1182 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1183 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1185 Enable NUMA (Non Uniform Memory Access) support.
1187 The kernel will try to allocate memory used by a CPU on the
1188 local memory controller of the CPU and add some more
1189 NUMA awareness to the kernel.
1191 For 64-bit this is recommended if the system is Intel Core i7
1192 (or later), AMD Opteron, or EM64T NUMA.
1194 For 32-bit this is only needed on (rare) 32-bit-only platforms
1195 that support NUMA topologies, such as NUMAQ / Summit, or if you
1196 boot a 32-bit kernel on a 64-bit NUMA platform.
1198 Otherwise, you should say N.
1200 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1201 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1205 prompt "Old style AMD Opteron NUMA detection"
1206 depends on X86_64 && NUMA && PCI
1208 Enable AMD NUMA node topology detection. You should say Y here if
1209 you have a multi processor AMD system. This uses an old method to
1210 read the NUMA configuration directly from the builtin Northbridge
1211 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1212 which also takes priority if both are compiled in.
1214 config X86_64_ACPI_NUMA
1216 prompt "ACPI NUMA detection"
1217 depends on X86_64 && NUMA && ACPI && PCI
1220 Enable ACPI SRAT based node topology detection.
1222 # Some NUMA nodes have memory ranges that span
1223 # other nodes. Even though a pfn is valid and
1224 # between a node's start and end pfns, it may not
1225 # reside on that node. See memmap_init_zone()
1227 config NODES_SPAN_OTHER_NODES
1229 depends on X86_64_ACPI_NUMA
1232 bool "NUMA emulation"
1235 Enable NUMA emulation. A flat machine will be split
1236 into virtual nodes when booted with "numa=fake=N", where N is the
1237 number of nodes. This is only useful for debugging.
1240 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1242 default "10" if MAXSMP
1243 default "6" if X86_64
1244 default "4" if X86_NUMAQ
1246 depends on NEED_MULTIPLE_NODES
1248 Specify the maximum number of NUMA Nodes available on the target
1249 system. Increases memory reserved to accommodate various tables.
1251 config HAVE_ARCH_ALLOC_REMAP
1253 depends on X86_32 && NUMA
1255 config ARCH_HAVE_MEMORY_PRESENT
1257 depends on X86_32 && DISCONTIGMEM
1259 config NEED_NODE_MEMMAP_SIZE
1261 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1263 config ARCH_FLATMEM_ENABLE
1265 depends on X86_32 && !NUMA
1267 config ARCH_DISCONTIGMEM_ENABLE
1269 depends on NUMA && X86_32
1271 config ARCH_DISCONTIGMEM_DEFAULT
1273 depends on NUMA && X86_32
1275 config ARCH_SPARSEMEM_ENABLE
1277 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1278 select SPARSEMEM_STATIC if X86_32
1279 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1281 config ARCH_SPARSEMEM_DEFAULT
1285 config ARCH_SELECT_MEMORY_MODEL
1287 depends on ARCH_SPARSEMEM_ENABLE
1289 config ARCH_MEMORY_PROBE
1291 depends on MEMORY_HOTPLUG
1293 config ARCH_PROC_KCORE_TEXT
1295 depends on X86_64 && PROC_KCORE
1297 config ILLEGAL_POINTER_VALUE
1300 default 0xdead000000000000 if X86_64
1305 bool "Allocate 3rd-level pagetables from highmem"
1308 The VM uses one page table entry for each page of physical memory.
1309 For systems with a lot of RAM, this can be wasteful of precious
1310 low memory. Setting this option will put user-space page table
1311 entries in high memory.
1313 config X86_CHECK_BIOS_CORRUPTION
1314 bool "Check for low memory corruption"
1316 Periodically check for memory corruption in low memory, which
1317 is suspected to be caused by BIOS. Even when enabled in the
1318 configuration, it is disabled at runtime. Enable it by
1319 setting "memory_corruption_check=1" on the kernel command
1320 line. By default it scans the low 64k of memory every 60
1321 seconds; see the memory_corruption_check_size and
1322 memory_corruption_check_period parameters in
1323 Documentation/kernel-parameters.txt to adjust this.
1325 When enabled with the default parameters, this option has
1326 almost no overhead, as it reserves a relatively small amount
1327 of memory and scans it infrequently. It both detects corruption
1328 and prevents it from affecting the running system.
1330 It is, however, intended as a diagnostic tool; if repeatable
1331 BIOS-originated corruption always affects the same memory,
1332 you can use memmap= to prevent the kernel from using that
1335 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1336 bool "Set the default setting of memory_corruption_check"
1337 depends on X86_CHECK_BIOS_CORRUPTION
1340 Set whether the default state of memory_corruption_check is
1343 config X86_RESERVE_LOW
1344 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1348 Specify the amount of low memory to reserve for the BIOS.
1350 The first page contains BIOS data structures that the kernel
1351 must not use, so that page must always be reserved.
1353 By default we reserve the first 64K of physical RAM, as a
1354 number of BIOSes are known to corrupt that memory range
1355 during events such as suspend/resume or monitor cable
1356 insertion, so it must not be used by the kernel.
1358 You can set this to 4 if you are absolutely sure that you
1359 trust the BIOS to get all its memory reservations and usages
1360 right. If you know your BIOS have problems beyond the
1361 default 64K area, you can set this to 640 to avoid using the
1362 entire low memory range.
1364 If you have doubts about the BIOS (e.g. suspend/resume does
1365 not work or there's kernel crashes after certain hardware
1366 hotplug events) then you might want to enable
1367 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1368 typical corruption patterns.
1370 Leave this to the default value of 64 if you are unsure.
1372 config MATH_EMULATION
1374 prompt "Math emulation" if X86_32
1376 Linux can emulate a math coprocessor (used for floating point
1377 operations) if you don't have one. 486DX and Pentium processors have
1378 a math coprocessor built in, 486SX and 386 do not, unless you added
1379 a 487DX or 387, respectively. (The messages during boot time can
1380 give you some hints here ["man dmesg"].) Everyone needs either a
1381 coprocessor or this emulation.
1383 If you don't have a math coprocessor, you need to say Y here; if you
1384 say Y here even though you have a coprocessor, the coprocessor will
1385 be used nevertheless. (This behavior can be changed with the kernel
1386 command line option "no387", which comes handy if your coprocessor
1387 is broken. Try "man bootparam" or see the documentation of your boot
1388 loader (lilo or loadlin) about how to pass options to the kernel at
1389 boot time.) This means that it is a good idea to say Y here if you
1390 intend to use this kernel on different machines.
1392 More information about the internals of the Linux math coprocessor
1393 emulation can be found in <file:arch/x86/math-emu/README>.
1395 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1396 kernel, it won't hurt.
1400 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1402 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1403 the Memory Type Range Registers (MTRRs) may be used to control
1404 processor access to memory ranges. This is most useful if you have
1405 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1406 allows bus write transfers to be combined into a larger transfer
1407 before bursting over the PCI/AGP bus. This can increase performance
1408 of image write operations 2.5 times or more. Saying Y here creates a
1409 /proc/mtrr file which may be used to manipulate your processor's
1410 MTRRs. Typically the X server should use this.
1412 This code has a reasonably generic interface so that similar
1413 control registers on other processors can be easily supported
1416 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1417 Registers (ARRs) which provide a similar functionality to MTRRs. For
1418 these, the ARRs are used to emulate the MTRRs.
1419 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1420 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1421 write-combining. All of these processors are supported by this code
1422 and it makes sense to say Y here if you have one of them.
1424 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1425 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1426 can lead to all sorts of problems, so it's good to say Y here.
1428 You can safely say Y even if your machine doesn't have MTRRs, you'll
1429 just add about 9 KB to your kernel.
1431 See <file:Documentation/x86/mtrr.txt> for more information.
1433 config MTRR_SANITIZER
1435 prompt "MTRR cleanup support"
1438 Convert MTRR layout from continuous to discrete, so X drivers can
1439 add writeback entries.
1441 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1442 The largest mtrr entry size for a continuous block can be set with
1447 config MTRR_SANITIZER_ENABLE_DEFAULT
1448 int "MTRR cleanup enable value (0-1)"
1451 depends on MTRR_SANITIZER
1453 Enable mtrr cleanup default value
1455 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1456 int "MTRR cleanup spare reg num (0-7)"
1459 depends on MTRR_SANITIZER
1461 mtrr cleanup spare entries default, it can be changed via
1462 mtrr_spare_reg_nr=N on the kernel command line.
1466 prompt "x86 PAT support" if EXPERT
1469 Use PAT attributes to setup page level cache control.
1471 PATs are the modern equivalents of MTRRs and are much more
1472 flexible than MTRRs.
1474 Say N here if you see bootup problems (boot crash, boot hang,
1475 spontaneous reboots) or a non-working video driver.
1479 config ARCH_USES_PG_UNCACHED
1485 prompt "x86 architectural random number generator" if EXPERT
1487 Enable the x86 architectural RDRAND instruction
1488 (Intel Bull Mountain technology) to generate random numbers.
1489 If supported, this is a high bandwidth, cryptographically
1490 secure hardware random number generator.
1493 bool "EFI runtime service support"
1496 This enables the kernel to use EFI runtime services that are
1497 available (such as the EFI variable services).
1499 This option is only useful on systems that have EFI firmware.
1500 In addition, you should use the latest ELILO loader available
1501 at <http://elilo.sourceforge.net> in order to take advantage
1502 of EFI runtime services. However, even with this option, the
1503 resultant kernel should continue to boot on existing non-EFI
1507 bool "EFI stub support"
1510 This kernel feature allows a bzImage to be loaded directly
1511 by EFI firmware without the use of a bootloader.
1513 See Documentation/x86/efi-stub.txt for more information.
1517 prompt "Enable seccomp to safely compute untrusted bytecode"
1519 This kernel feature is useful for number crunching applications
1520 that may need to compute untrusted bytecode during their
1521 execution. By using pipes or other transports made available to
1522 the process as file descriptors supporting the read/write
1523 syscalls, it's possible to isolate those applications in
1524 their own address space using seccomp. Once seccomp is
1525 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1526 and the task is only allowed to execute a few safe syscalls
1527 defined by each seccomp mode.
1529 If unsure, say Y. Only embedded should say N here.
1531 config CC_STACKPROTECTOR
1532 bool "Enable -fstack-protector buffer overflow detection"
1534 This option turns on the -fstack-protector GCC feature. This
1535 feature puts, at the beginning of functions, a canary value on
1536 the stack just before the return address, and validates
1537 the value just before actually returning. Stack based buffer
1538 overflows (that need to overwrite this return address) now also
1539 overwrite the canary, which gets detected and the attack is then
1540 neutralized via a kernel panic.
1542 This feature requires gcc version 4.2 or above, or a distribution
1543 gcc with the feature backported. Older versions are automatically
1544 detected and for those versions, this configuration option is
1545 ignored. (and a warning is printed during bootup)
1547 source kernel/Kconfig.hz
1550 bool "kexec system call"
1552 kexec is a system call that implements the ability to shutdown your
1553 current kernel, and to start another kernel. It is like a reboot
1554 but it is independent of the system firmware. And like a reboot
1555 you can start any kernel with it, not just Linux.
1557 The name comes from the similarity to the exec system call.
1559 It is an ongoing process to be certain the hardware in a machine
1560 is properly shutdown, so do not be surprised if this code does not
1561 initially work for you. It may help to enable device hotplugging
1562 support. As of this writing the exact hardware interface is
1563 strongly in flux, so no good recommendation can be made.
1566 bool "kernel crash dumps"
1567 depends on X86_64 || (X86_32 && HIGHMEM)
1569 Generate crash dump after being started by kexec.
1570 This should be normally only set in special crash dump kernels
1571 which are loaded in the main kernel with kexec-tools into
1572 a specially reserved region and then later executed after
1573 a crash by kdump/kexec. The crash dump kernel must be compiled
1574 to a memory address not used by the main kernel or BIOS using
1575 PHYSICAL_START, or it must be built as a relocatable image
1576 (CONFIG_RELOCATABLE=y).
1577 For more details see Documentation/kdump/kdump.txt
1580 bool "kexec jump (EXPERIMENTAL)"
1581 depends on EXPERIMENTAL
1582 depends on KEXEC && HIBERNATION
1584 Jump between original kernel and kexeced kernel and invoke
1585 code in physical address mode via KEXEC
1587 config PHYSICAL_START
1588 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1591 This gives the physical address where the kernel is loaded.
1593 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1594 bzImage will decompress itself to above physical address and
1595 run from there. Otherwise, bzImage will run from the address where
1596 it has been loaded by the boot loader and will ignore above physical
1599 In normal kdump cases one does not have to set/change this option
1600 as now bzImage can be compiled as a completely relocatable image
1601 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1602 address. This option is mainly useful for the folks who don't want
1603 to use a bzImage for capturing the crash dump and want to use a
1604 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1605 to be specifically compiled to run from a specific memory area
1606 (normally a reserved region) and this option comes handy.
1608 So if you are using bzImage for capturing the crash dump,
1609 leave the value here unchanged to 0x1000000 and set
1610 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1611 for capturing the crash dump change this value to start of
1612 the reserved region. In other words, it can be set based on
1613 the "X" value as specified in the "crashkernel=YM@XM"
1614 command line boot parameter passed to the panic-ed
1615 kernel. Please take a look at Documentation/kdump/kdump.txt
1616 for more details about crash dumps.
1618 Usage of bzImage for capturing the crash dump is recommended as
1619 one does not have to build two kernels. Same kernel can be used
1620 as production kernel and capture kernel. Above option should have
1621 gone away after relocatable bzImage support is introduced. But it
1622 is present because there are users out there who continue to use
1623 vmlinux for dump capture. This option should go away down the
1626 Don't change this unless you know what you are doing.
1629 bool "Build a relocatable kernel"
1632 This builds a kernel image that retains relocation information
1633 so it can be loaded someplace besides the default 1MB.
1634 The relocations tend to make the kernel binary about 10% larger,
1635 but are discarded at runtime.
1637 One use is for the kexec on panic case where the recovery kernel
1638 must live at a different physical address than the primary
1641 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1642 it has been loaded at and the compile time physical address
1643 (CONFIG_PHYSICAL_START) is ignored.
1645 # Relocation on x86-32 needs some additional build support
1646 config X86_NEED_RELOCS
1648 depends on X86_32 && RELOCATABLE
1650 config PHYSICAL_ALIGN
1651 hex "Alignment value to which kernel should be aligned" if X86_32
1653 range 0x2000 0x1000000
1655 This value puts the alignment restrictions on physical address
1656 where kernel is loaded and run from. Kernel is compiled for an
1657 address which meets above alignment restriction.
1659 If bootloader loads the kernel at a non-aligned address and
1660 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1661 address aligned to above value and run from there.
1663 If bootloader loads the kernel at a non-aligned address and
1664 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1665 load address and decompress itself to the address it has been
1666 compiled for and run from there. The address for which kernel is
1667 compiled already meets above alignment restrictions. Hence the
1668 end result is that kernel runs from a physical address meeting
1669 above alignment restrictions.
1671 Don't change this unless you know what you are doing.
1674 bool "Support for hot-pluggable CPUs"
1675 depends on SMP && HOTPLUG
1677 Say Y here to allow turning CPUs off and on. CPUs can be
1678 controlled through /sys/devices/system/cpu.
1679 ( Note: power management support will enable this option
1680 automatically on SMP systems. )
1681 Say N if you want to disable CPU hotplug.
1685 prompt "Compat VDSO support"
1686 depends on X86_32 || IA32_EMULATION
1688 Map the 32-bit VDSO to the predictable old-style address too.
1690 Say N here if you are running a sufficiently recent glibc
1691 version (2.3.3 or later), to remove the high-mapped
1692 VDSO mapping and to exclusively use the randomized VDSO.
1697 bool "Built-in kernel command line"
1699 Allow for specifying boot arguments to the kernel at
1700 build time. On some systems (e.g. embedded ones), it is
1701 necessary or convenient to provide some or all of the
1702 kernel boot arguments with the kernel itself (that is,
1703 to not rely on the boot loader to provide them.)
1705 To compile command line arguments into the kernel,
1706 set this option to 'Y', then fill in the
1707 the boot arguments in CONFIG_CMDLINE.
1709 Systems with fully functional boot loaders (i.e. non-embedded)
1710 should leave this option set to 'N'.
1713 string "Built-in kernel command string"
1714 depends on CMDLINE_BOOL
1717 Enter arguments here that should be compiled into the kernel
1718 image and used at boot time. If the boot loader provides a
1719 command line at boot time, it is appended to this string to
1720 form the full kernel command line, when the system boots.
1722 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1723 change this behavior.
1725 In most cases, the command line (whether built-in or provided
1726 by the boot loader) should specify the device for the root
1729 config CMDLINE_OVERRIDE
1730 bool "Built-in command line overrides boot loader arguments"
1731 depends on CMDLINE_BOOL
1733 Set this option to 'Y' to have the kernel ignore the boot loader
1734 command line, and use ONLY the built-in command line.
1736 This is used to work around broken boot loaders. This should
1737 be set to 'N' under normal conditions.
1741 config ARCH_ENABLE_MEMORY_HOTPLUG
1743 depends on X86_64 || (X86_32 && HIGHMEM)
1745 config ARCH_ENABLE_MEMORY_HOTREMOVE
1747 depends on MEMORY_HOTPLUG
1749 config USE_PERCPU_NUMA_NODE_ID
1753 menu "Power management and ACPI options"
1755 config ARCH_HIBERNATION_HEADER
1757 depends on X86_64 && HIBERNATION
1759 source "kernel/power/Kconfig"
1761 source "drivers/acpi/Kconfig"
1763 source "drivers/sfi/Kconfig"
1770 tristate "APM (Advanced Power Management) BIOS support"
1771 depends on X86_32 && PM_SLEEP
1773 APM is a BIOS specification for saving power using several different
1774 techniques. This is mostly useful for battery powered laptops with
1775 APM compliant BIOSes. If you say Y here, the system time will be
1776 reset after a RESUME operation, the /proc/apm device will provide
1777 battery status information, and user-space programs will receive
1778 notification of APM "events" (e.g. battery status change).
1780 If you select "Y" here, you can disable actual use of the APM
1781 BIOS by passing the "apm=off" option to the kernel at boot time.
1783 Note that the APM support is almost completely disabled for
1784 machines with more than one CPU.
1786 In order to use APM, you will need supporting software. For location
1787 and more information, read <file:Documentation/power/apm-acpi.txt>
1788 and the Battery Powered Linux mini-HOWTO, available from
1789 <http://www.tldp.org/docs.html#howto>.
1791 This driver does not spin down disk drives (see the hdparm(8)
1792 manpage ("man 8 hdparm") for that), and it doesn't turn off
1793 VESA-compliant "green" monitors.
1795 This driver does not support the TI 4000M TravelMate and the ACER
1796 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1797 desktop machines also don't have compliant BIOSes, and this driver
1798 may cause those machines to panic during the boot phase.
1800 Generally, if you don't have a battery in your machine, there isn't
1801 much point in using this driver and you should say N. If you get
1802 random kernel OOPSes or reboots that don't seem to be related to
1803 anything, try disabling/enabling this option (or disabling/enabling
1806 Some other things you should try when experiencing seemingly random,
1809 1) make sure that you have enough swap space and that it is
1811 2) pass the "no-hlt" option to the kernel
1812 3) switch on floating point emulation in the kernel and pass
1813 the "no387" option to the kernel
1814 4) pass the "floppy=nodma" option to the kernel
1815 5) pass the "mem=4M" option to the kernel (thereby disabling
1816 all but the first 4 MB of RAM)
1817 6) make sure that the CPU is not over clocked.
1818 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1819 8) disable the cache from your BIOS settings
1820 9) install a fan for the video card or exchange video RAM
1821 10) install a better fan for the CPU
1822 11) exchange RAM chips
1823 12) exchange the motherboard.
1825 To compile this driver as a module, choose M here: the
1826 module will be called apm.
1830 config APM_IGNORE_USER_SUSPEND
1831 bool "Ignore USER SUSPEND"
1833 This option will ignore USER SUSPEND requests. On machines with a
1834 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1835 series notebooks, it is necessary to say Y because of a BIOS bug.
1837 config APM_DO_ENABLE
1838 bool "Enable PM at boot time"
1840 Enable APM features at boot time. From page 36 of the APM BIOS
1841 specification: "When disabled, the APM BIOS does not automatically
1842 power manage devices, enter the Standby State, enter the Suspend
1843 State, or take power saving steps in response to CPU Idle calls."
1844 This driver will make CPU Idle calls when Linux is idle (unless this
1845 feature is turned off -- see "Do CPU IDLE calls", below). This
1846 should always save battery power, but more complicated APM features
1847 will be dependent on your BIOS implementation. You may need to turn
1848 this option off if your computer hangs at boot time when using APM
1849 support, or if it beeps continuously instead of suspending. Turn
1850 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1851 T400CDT. This is off by default since most machines do fine without
1855 bool "Make CPU Idle calls when idle"
1857 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1858 On some machines, this can activate improved power savings, such as
1859 a slowed CPU clock rate, when the machine is idle. These idle calls
1860 are made after the idle loop has run for some length of time (e.g.,
1861 333 mS). On some machines, this will cause a hang at boot time or
1862 whenever the CPU becomes idle. (On machines with more than one CPU,
1863 this option does nothing.)
1865 config APM_DISPLAY_BLANK
1866 bool "Enable console blanking using APM"
1868 Enable console blanking using the APM. Some laptops can use this to
1869 turn off the LCD backlight when the screen blanker of the Linux
1870 virtual console blanks the screen. Note that this is only used by
1871 the virtual console screen blanker, and won't turn off the backlight
1872 when using the X Window system. This also doesn't have anything to
1873 do with your VESA-compliant power-saving monitor. Further, this
1874 option doesn't work for all laptops -- it might not turn off your
1875 backlight at all, or it might print a lot of errors to the console,
1876 especially if you are using gpm.
1878 config APM_ALLOW_INTS
1879 bool "Allow interrupts during APM BIOS calls"
1881 Normally we disable external interrupts while we are making calls to
1882 the APM BIOS as a measure to lessen the effects of a badly behaving
1883 BIOS implementation. The BIOS should reenable interrupts if it
1884 needs to. Unfortunately, some BIOSes do not -- especially those in
1885 many of the newer IBM Thinkpads. If you experience hangs when you
1886 suspend, try setting this to Y. Otherwise, say N.
1890 source "drivers/cpufreq/Kconfig"
1892 source "drivers/cpuidle/Kconfig"
1894 source "drivers/idle/Kconfig"
1899 menu "Bus options (PCI etc.)"
1904 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1906 Find out whether you have a PCI motherboard. PCI is the name of a
1907 bus system, i.e. the way the CPU talks to the other stuff inside
1908 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1909 VESA. If you have PCI, say Y, otherwise N.
1912 prompt "PCI access mode"
1913 depends on X86_32 && PCI
1916 On PCI systems, the BIOS can be used to detect the PCI devices and
1917 determine their configuration. However, some old PCI motherboards
1918 have BIOS bugs and may crash if this is done. Also, some embedded
1919 PCI-based systems don't have any BIOS at all. Linux can also try to
1920 detect the PCI hardware directly without using the BIOS.
1922 With this option, you can specify how Linux should detect the
1923 PCI devices. If you choose "BIOS", the BIOS will be used,
1924 if you choose "Direct", the BIOS won't be used, and if you
1925 choose "MMConfig", then PCI Express MMCONFIG will be used.
1926 If you choose "Any", the kernel will try MMCONFIG, then the
1927 direct access method and falls back to the BIOS if that doesn't
1928 work. If unsure, go with the default, which is "Any".
1933 config PCI_GOMMCONFIG
1950 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1952 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1955 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1959 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1963 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1967 depends on PCI && XEN
1975 bool "Support mmconfig PCI config space access"
1976 depends on X86_64 && PCI && ACPI
1978 config PCI_CNB20LE_QUIRK
1979 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1981 depends on PCI && EXPERIMENTAL
1983 Read the PCI windows out of the CNB20LE host bridge. This allows
1984 PCI hotplug to work on systems with the CNB20LE chipset which do
1987 There's no public spec for this chipset, and this functionality
1988 is known to be incomplete.
1990 You should say N unless you know you need this.
1992 source "drivers/pci/pcie/Kconfig"
1994 source "drivers/pci/Kconfig"
1996 # x86_64 have no ISA slots, but can have ISA-style DMA.
1998 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2001 Enables ISA-style DMA support for devices requiring such controllers.
2009 Find out whether you have ISA slots on your motherboard. ISA is the
2010 name of a bus system, i.e. the way the CPU talks to the other stuff
2011 inside your box. Other bus systems are PCI, EISA, MicroChannel
2012 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2013 newer boards don't support it. If you have ISA, say Y, otherwise N.
2019 The Extended Industry Standard Architecture (EISA) bus was
2020 developed as an open alternative to the IBM MicroChannel bus.
2022 The EISA bus provided some of the features of the IBM MicroChannel
2023 bus while maintaining backward compatibility with cards made for
2024 the older ISA bus. The EISA bus saw limited use between 1988 and
2025 1995 when it was made obsolete by the PCI bus.
2027 Say Y here if you are building a kernel for an EISA-based machine.
2031 source "drivers/eisa/Kconfig"
2034 tristate "NatSemi SCx200 support"
2036 This provides basic support for National Semiconductor's
2037 (now AMD's) Geode processors. The driver probes for the
2038 PCI-IDs of several on-chip devices, so its a good dependency
2039 for other scx200_* drivers.
2041 If compiled as a module, the driver is named scx200.
2043 config SCx200HR_TIMER
2044 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2048 This driver provides a clocksource built upon the on-chip
2049 27MHz high-resolution timer. Its also a workaround for
2050 NSC Geode SC-1100's buggy TSC, which loses time when the
2051 processor goes idle (as is done by the scheduler). The
2052 other workaround is idle=poll boot option.
2055 bool "One Laptop Per Child support"
2062 Add support for detecting the unique features of the OLPC
2066 bool "OLPC XO-1 Power Management"
2067 depends on OLPC && MFD_CS5535 && PM_SLEEP
2070 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2073 bool "OLPC XO-1 Real Time Clock"
2074 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2076 Add support for the XO-1 real time clock, which can be used as a
2077 programmable wakeup source.
2080 bool "OLPC XO-1 SCI extras"
2081 depends on OLPC && OLPC_XO1_PM
2086 Add support for SCI-based features of the OLPC XO-1 laptop:
2087 - EC-driven system wakeups
2091 - AC adapter status updates
2092 - Battery status updates
2094 config OLPC_XO15_SCI
2095 bool "OLPC XO-1.5 SCI extras"
2096 depends on OLPC && ACPI
2099 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2100 - EC-driven system wakeups
2101 - AC adapter status updates
2102 - Battery status updates
2105 bool "PCEngines ALIX System Support (LED setup)"
2108 This option enables system support for the PCEngines ALIX.
2109 At present this just sets up LEDs for GPIO control on
2110 ALIX2/3/6 boards. However, other system specific setup should
2113 Note: You must still enable the drivers for GPIO and LED support
2114 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2116 Note: You have to set alix.force=1 for boards with Award BIOS.
2119 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2122 This option enables system support for the Soekris Engineering net5501.
2125 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2129 This option enables system support for the Traverse Technologies GEOS.
2135 depends on CPU_SUP_AMD && PCI
2137 source "drivers/pcmcia/Kconfig"
2139 source "drivers/pci/hotplug/Kconfig"
2142 bool "RapidIO support"
2146 If you say Y here, the kernel will include drivers and
2147 infrastructure code to support RapidIO interconnect devices.
2149 source "drivers/rapidio/Kconfig"
2154 menu "Executable file formats / Emulations"
2156 source "fs/Kconfig.binfmt"
2158 config IA32_EMULATION
2159 bool "IA32 Emulation"
2161 select COMPAT_BINFMT_ELF
2163 Include code to run legacy 32-bit programs under a
2164 64-bit kernel. You should likely turn this on, unless you're
2165 100% sure that you don't have any 32-bit programs left.
2168 tristate "IA32 a.out support"
2169 depends on IA32_EMULATION
2171 Support old a.out binaries in the 32bit emulation.
2174 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2175 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2177 Include code to run binaries for the x32 native 32-bit ABI
2178 for 64-bit processors. An x32 process gets access to the
2179 full 64-bit register file and wide data path while leaving
2180 pointers at 32 bits for smaller memory footprint.
2182 You will need a recent binutils (2.22 or later) with
2183 elf32_x86_64 support enabled to compile a kernel with this
2188 depends on IA32_EMULATION || X86_X32
2189 select ARCH_WANT_OLD_COMPAT_IPC
2191 config COMPAT_FOR_U64_ALIGNMENT
2195 config SYSVIPC_COMPAT
2197 depends on COMPAT && SYSVIPC
2201 depends on COMPAT && KEYS
2207 config HAVE_ATOMIC_IOMAP
2211 config HAVE_TEXT_POKE_SMP
2213 select STOP_MACHINE if SMP
2215 config X86_DEV_DMA_OPS
2217 depends on X86_64 || STA2X11
2219 config X86_DMA_REMAP
2223 source "net/Kconfig"
2225 source "drivers/Kconfig"
2227 source "drivers/firmware/Kconfig"
2231 source "arch/x86/Kconfig.debug"
2233 source "security/Kconfig"
2235 source "crypto/Kconfig"
2237 source "arch/x86/kvm/Kconfig"
2239 source "lib/Kconfig"