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
73 select HAVE_CMPXCHG_LOCAL
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_CONTEXT_TRACKING if X86_64
110 select HAVE_IRQ_TIME_ACCOUNTING
111 select GENERIC_KERNEL_THREAD
112 select GENERIC_KERNEL_EXECVE
113 select MODULES_USE_ELF_REL if X86_32
114 select MODULES_USE_ELF_RELA if X86_64
115 select CLONE_BACKWARDS if X86_32
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_XCHGADD_ALGORITHM
178 config GENERIC_CALIBRATE_DELAY
181 config ARCH_HAS_CPU_RELAX
184 config ARCH_HAS_DEFAULT_IDLE
187 config ARCH_HAS_CACHE_LINE_SIZE
190 config ARCH_HAS_CPU_AUTOPROBE
193 config HAVE_SETUP_PER_CPU_AREA
196 config NEED_PER_CPU_EMBED_FIRST_CHUNK
199 config NEED_PER_CPU_PAGE_FIRST_CHUNK
202 config ARCH_HIBERNATION_POSSIBLE
205 config ARCH_SUSPEND_POSSIBLE
216 config ARCH_SUPPORTS_OPTIMIZED_INLINING
219 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
222 config HAVE_INTEL_TXT
224 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
228 depends on X86_32 && SMP
232 depends on X86_64 && SMP
238 config X86_32_LAZY_GS
240 depends on X86_32 && !CC_STACKPROTECTOR
242 config ARCH_HWEIGHT_CFLAGS
244 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
245 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
247 config ARCH_CPU_PROBE_RELEASE
249 depends on HOTPLUG_CPU
251 config ARCH_SUPPORTS_UPROBES
254 source "init/Kconfig"
255 source "kernel/Kconfig.freezer"
257 menu "Processor type and features"
260 bool "DMA memory allocation support" if EXPERT
263 DMA memory allocation support allows devices with less than 32-bit
264 addressing to allocate within the first 16MB of address space.
265 Disable if no such devices will be used.
270 bool "Symmetric multi-processing support"
272 This enables support for systems with more than one CPU. If you have
273 a system with only one CPU, like most personal computers, say N. If
274 you have a system with more than one CPU, say Y.
276 If you say N here, the kernel will run on single and multiprocessor
277 machines, but will use only one CPU of a multiprocessor machine. If
278 you say Y here, the kernel will run on many, but not all,
279 singleprocessor machines. On a singleprocessor machine, the kernel
280 will run faster if you say N here.
282 Note that if you say Y here and choose architecture "586" or
283 "Pentium" under "Processor family", the kernel will not work on 486
284 architectures. Similarly, multiprocessor kernels for the "PPro"
285 architecture may not work on all Pentium based boards.
287 People using multiprocessor machines who say Y here should also say
288 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
289 Management" code will be disabled if you say Y here.
291 See also <file:Documentation/x86/i386/IO-APIC.txt>,
292 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
293 <http://www.tldp.org/docs.html#howto>.
295 If you don't know what to do here, say N.
298 bool "Support x2apic"
299 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
301 This enables x2apic support on CPUs that have this feature.
303 This allows 32-bit apic IDs (so it can support very large systems),
304 and accesses the local apic via MSRs not via mmio.
306 If you don't know what to do here, say N.
309 bool "Enable MPS table" if ACPI || SFI
311 depends on X86_LOCAL_APIC
313 For old smp systems that do not have proper acpi support. Newer systems
314 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
317 bool "Support for big SMP systems with more than 8 CPUs"
318 depends on X86_32 && SMP
320 This option is needed for the systems that have more than 8 CPUs
323 config X86_EXTENDED_PLATFORM
324 bool "Support for extended (non-PC) x86 platforms"
327 If you disable this option then the kernel will only support
328 standard PC platforms. (which covers the vast majority of
331 If you enable this option then you'll be able to select support
332 for the following (non-PC) 32 bit x86 platforms:
336 SGI 320/540 (Visual Workstation)
337 STA2X11-based (e.g. Northville)
338 Summit/EXA (IBM x440)
339 Unisys ES7000 IA32 series
340 Moorestown MID devices
342 If you have one of these systems, or if you want to build a
343 generic distribution kernel, say Y here - otherwise say N.
347 config X86_EXTENDED_PLATFORM
348 bool "Support for extended (non-PC) x86 platforms"
351 If you disable this option then the kernel will only support
352 standard PC platforms. (which covers the vast majority of
355 If you enable this option then you'll be able to select support
356 for the following (non-PC) 64 bit x86 platforms:
361 If you have one of these systems, or if you want to build a
362 generic distribution kernel, say Y here - otherwise say N.
364 # This is an alphabetically sorted list of 64 bit extended platforms
365 # Please maintain the alphabetic order if and when there are additions
367 bool "Numascale NumaChip"
369 depends on X86_EXTENDED_PLATFORM
372 depends on X86_X2APIC
374 Adds support for Numascale NumaChip large-SMP systems. Needed to
375 enable more than ~168 cores.
376 If you don't have one of these, you should say N here.
380 select PARAVIRT_GUEST
382 depends on X86_64 && PCI
383 depends on X86_EXTENDED_PLATFORM
386 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
387 supposed to run on these EM64T-based machines. Only choose this option
388 if you have one of these machines.
391 bool "SGI Ultraviolet"
393 depends on X86_EXTENDED_PLATFORM
395 depends on X86_X2APIC
397 This option is needed in order to support SGI Ultraviolet systems.
398 If you don't have one of these, you should say N here.
400 # Following is an alphabetically sorted list of 32 bit extended platforms
401 # Please maintain the alphabetic order if and when there are additions
404 bool "CE4100 TV platform"
406 depends on PCI_GODIRECT
408 depends on X86_EXTENDED_PLATFORM
409 select X86_REBOOTFIXUPS
411 select OF_EARLY_FLATTREE
414 Select for the Intel CE media processor (CE4100) SOC.
415 This option compiles in support for the CE4100 SOC for settop
416 boxes and media devices.
418 config X86_WANT_INTEL_MID
419 bool "Intel MID platform support"
421 depends on X86_EXTENDED_PLATFORM
423 Select to build a kernel capable of supporting Intel MID platform
424 systems which do not have the PCI legacy interfaces (Moorestown,
425 Medfield). If you are building for a PC class system say N here.
427 if X86_WANT_INTEL_MID
433 bool "Medfield MID platform"
436 depends on X86_IO_APIC
444 select X86_PLATFORM_DEVICES
445 select MFD_INTEL_MSIC
447 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
448 Internet Device(MID) platform.
449 Unlike standard x86 PCs, Medfield does not have many legacy devices
450 nor standard legacy replacement devices/features. e.g. Medfield does
451 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
456 bool "RDC R-321x SoC"
458 depends on X86_EXTENDED_PLATFORM
460 select X86_REBOOTFIXUPS
462 This option is needed for RDC R-321x system-on-chip, also known
464 If you don't have one of these chips, you should say N here.
466 config X86_32_NON_STANDARD
467 bool "Support non-standard 32-bit SMP architectures"
468 depends on X86_32 && SMP
469 depends on X86_EXTENDED_PLATFORM
471 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
472 STA2X11, default subarchitectures. It is intended for a generic
473 binary kernel. If you select them all, kernel will probe it
474 one by one and will fallback to default.
476 # Alphabetically sorted list of Non standard 32 bit platforms
479 bool "NUMAQ (IBM/Sequent)"
480 depends on X86_32_NON_STANDARD
485 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
486 NUMA multiquad box. This changes the way that processors are
487 bootstrapped, and uses Clustered Logical APIC addressing mode instead
488 of Flat Logical. You will need a new lynxer.elf file to flash your
489 firmware with - send email to <Martin.Bligh@us.ibm.com>.
491 config X86_SUPPORTS_MEMORY_FAILURE
493 # MCE code calls memory_failure():
495 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
496 depends on !X86_NUMAQ
497 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
498 depends on X86_64 || !SPARSEMEM
499 select ARCH_SUPPORTS_MEMORY_FAILURE
502 bool "SGI 320/540 (Visual Workstation)"
503 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
504 depends on X86_32_NON_STANDARD
506 The SGI Visual Workstation series is an IA32-based workstation
507 based on SGI systems chips with some legacy PC hardware attached.
509 Say Y here to create a kernel to run on the SGI 320 or 540.
511 A kernel compiled for the Visual Workstation will run on general
512 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
515 bool "STA2X11 Companion Chip Support"
516 depends on X86_32_NON_STANDARD && PCI
517 select X86_DEV_DMA_OPS
521 select ARCH_REQUIRE_GPIOLIB
524 This adds support for boards based on the STA2X11 IO-Hub,
525 a.k.a. "ConneXt". The chip is used in place of the standard
526 PC chipset, so all "standard" peripherals are missing. If this
527 option is selected the kernel will still be able to boot on
528 standard PC machines.
531 bool "Summit/EXA (IBM x440)"
532 depends on X86_32_NON_STANDARD
534 This option is needed for IBM systems that use the Summit/EXA chipset.
535 In particular, it is needed for the x440.
538 bool "Unisys ES7000 IA32 series"
539 depends on X86_32_NON_STANDARD && X86_BIGSMP
541 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
542 supposed to run on an IA32-based Unisys ES7000 system.
545 tristate "Eurobraille/Iris poweroff module"
548 The Iris machines from EuroBraille do not have APM or ACPI support
549 to shut themselves down properly. A special I/O sequence is
550 needed to do so, which is what this module does at
553 This is only for Iris machines from EuroBraille.
557 config SCHED_OMIT_FRAME_POINTER
559 prompt "Single-depth WCHAN output"
562 Calculate simpler /proc/<PID>/wchan values. If this option
563 is disabled then wchan values will recurse back to the
564 caller function. This provides more accurate wchan values,
565 at the expense of slightly more scheduling overhead.
567 If in doubt, say "Y".
569 menuconfig PARAVIRT_GUEST
570 bool "Paravirtualized guest support"
572 Say Y here to get to see options related to running Linux under
573 various hypervisors. This option alone does not add any kernel code.
575 If you say N, all options in this submenu will be skipped and disabled.
579 config PARAVIRT_TIME_ACCOUNTING
580 bool "Paravirtual steal time accounting"
584 Select this option to enable fine granularity task steal time
585 accounting. Time spent executing other tasks in parallel with
586 the current vCPU is discounted from the vCPU power. To account for
587 that, there can be a small performance impact.
589 If in doubt, say N here.
591 source "arch/x86/xen/Kconfig"
594 bool "KVM Guest support (including kvmclock)"
597 select PARAVIRT_CLOCK
598 default y if PARAVIRT_GUEST
600 This option enables various optimizations for running under the KVM
601 hypervisor. It includes a paravirtualized clock, so that instead
602 of relying on a PIT (or probably other) emulation by the
603 underlying device model, the host provides the guest with
604 timing infrastructure such as time of day, and system time
606 source "arch/x86/lguest/Kconfig"
609 bool "Enable paravirtualization code"
611 This changes the kernel so it can modify itself when it is run
612 under a hypervisor, potentially improving performance significantly
613 over full virtualization. However, when run without a hypervisor
614 the kernel is theoretically slower and slightly larger.
616 config PARAVIRT_SPINLOCKS
617 bool "Paravirtualization layer for spinlocks"
618 depends on PARAVIRT && SMP && EXPERIMENTAL
620 Paravirtualized spinlocks allow a pvops backend to replace the
621 spinlock implementation with something virtualization-friendly
622 (for example, block the virtual CPU rather than spinning).
624 Unfortunately the downside is an up to 5% performance hit on
625 native kernels, with various workloads.
627 If you are unsure how to answer this question, answer N.
629 config PARAVIRT_CLOCK
634 config PARAVIRT_DEBUG
635 bool "paravirt-ops debugging"
636 depends on PARAVIRT && DEBUG_KERNEL
638 Enable to debug paravirt_ops internals. Specifically, BUG if
639 a paravirt_op is missing when it is called.
647 This option adds a kernel parameter 'memtest', which allows memtest
649 memtest=0, mean disabled; -- default
650 memtest=1, mean do 1 test pattern;
652 memtest=4, mean do 4 test patterns.
653 If you are unsure how to answer this question, answer N.
655 config X86_SUMMIT_NUMA
657 depends on X86_32 && NUMA && X86_32_NON_STANDARD
659 config X86_CYCLONE_TIMER
661 depends on X86_SUMMIT
663 source "arch/x86/Kconfig.cpu"
667 prompt "HPET Timer Support" if X86_32
669 Use the IA-PC HPET (High Precision Event Timer) to manage
670 time in preference to the PIT and RTC, if a HPET is
672 HPET is the next generation timer replacing legacy 8254s.
673 The HPET provides a stable time base on SMP
674 systems, unlike the TSC, but it is more expensive to access,
675 as it is off-chip. You can find the HPET spec at
676 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
678 You can safely choose Y here. However, HPET will only be
679 activated if the platform and the BIOS support this feature.
680 Otherwise the 8254 will be used for timing services.
682 Choose N to continue using the legacy 8254 timer.
684 config HPET_EMULATE_RTC
686 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
689 def_bool y if X86_INTEL_MID
690 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
692 depends on X86_INTEL_MID && SFI
694 APB timer is the replacement for 8254, HPET on X86 MID platforms.
695 The APBT provides a stable time base on SMP
696 systems, unlike the TSC, but it is more expensive to access,
697 as it is off-chip. APB timers are always running regardless of CPU
698 C states, they are used as per CPU clockevent device when possible.
700 # Mark as expert because too many people got it wrong.
701 # The code disables itself when not needed.
704 bool "Enable DMI scanning" if EXPERT
706 Enabled scanning of DMI to identify machine quirks. Say Y
707 here unless you have verified that your setup is not
708 affected by entries in the DMI blacklist. Required by PNP
712 bool "GART IOMMU support" if EXPERT
715 depends on X86_64 && PCI && AMD_NB
717 Support for full DMA access of devices with 32bit memory access only
718 on systems with more than 3GB. This is usually needed for USB,
719 sound, many IDE/SATA chipsets and some other devices.
720 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
721 based hardware IOMMU and a software bounce buffer based IOMMU used
722 on Intel systems and as fallback.
723 The code is only active when needed (enough memory and limited
724 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
728 bool "IBM Calgary IOMMU support"
730 depends on X86_64 && PCI && EXPERIMENTAL
732 Support for hardware IOMMUs in IBM's xSeries x366 and x460
733 systems. Needed to run systems with more than 3GB of memory
734 properly with 32-bit PCI devices that do not support DAC
735 (Double Address Cycle). Calgary also supports bus level
736 isolation, where all DMAs pass through the IOMMU. This
737 prevents them from going anywhere except their intended
738 destination. This catches hard-to-find kernel bugs and
739 mis-behaving drivers and devices that do not use the DMA-API
740 properly to set up their DMA buffers. The IOMMU can be
741 turned off at boot time with the iommu=off parameter.
742 Normally the kernel will make the right choice by itself.
745 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
747 prompt "Should Calgary be enabled by default?"
748 depends on CALGARY_IOMMU
750 Should Calgary be enabled by default? if you choose 'y', Calgary
751 will be used (if it exists). If you choose 'n', Calgary will not be
752 used even if it exists. If you choose 'n' and would like to use
753 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
756 # need this always selected by IOMMU for the VIA workaround
760 Support for software bounce buffers used on x86-64 systems
761 which don't have a hardware IOMMU. Using this PCI devices
762 which can only access 32-bits of memory can be used on systems
763 with more than 3 GB of memory.
768 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
771 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
772 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
773 select CPUMASK_OFFSTACK
775 Enable maximum number of CPUS and NUMA Nodes for this architecture.
779 int "Maximum number of CPUs" if SMP && !MAXSMP
780 range 2 8 if SMP && X86_32 && !X86_BIGSMP
781 range 2 512 if SMP && !MAXSMP
783 default "4096" if MAXSMP
784 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
787 This allows you to specify the maximum number of CPUs which this
788 kernel will support. The maximum supported value is 512 and the
789 minimum value which makes sense is 2.
791 This is purely to save memory - each supported CPU adds
792 approximately eight kilobytes to the kernel image.
795 bool "SMT (Hyperthreading) scheduler support"
798 SMT scheduler support improves the CPU scheduler's decision making
799 when dealing with Intel Pentium 4 chips with HyperThreading at a
800 cost of slightly increased overhead in some places. If unsure say
805 prompt "Multi-core scheduler support"
808 Multi-core scheduler support improves the CPU scheduler's decision
809 making when dealing with multi-core CPU chips at a cost of slightly
810 increased overhead in some places. If unsure 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"
878 Machine Check support allows the processor to notify the
879 kernel if it detects a problem (e.g. overheating, data corruption).
880 The action the kernel takes depends on the severity of the problem,
881 ranging from warning messages to halting the machine.
885 prompt "Intel MCE features"
886 depends on X86_MCE && X86_LOCAL_APIC
888 Additional support for intel specific MCE features such as
893 prompt "AMD MCE features"
894 depends on X86_MCE && X86_LOCAL_APIC
896 Additional support for AMD specific MCE features such as
897 the DRAM Error Threshold.
899 config X86_ANCIENT_MCE
900 bool "Support for old Pentium 5 / WinChip machine checks"
901 depends on X86_32 && X86_MCE
903 Include support for machine check handling on old Pentium 5 or WinChip
904 systems. These typically need to be enabled explicitely on the command
907 config X86_MCE_THRESHOLD
908 depends on X86_MCE_AMD || X86_MCE_INTEL
911 config X86_MCE_INJECT
913 tristate "Machine check injector support"
915 Provide support for injecting machine checks for testing purposes.
916 If you don't know what a machine check is and you don't do kernel
917 QA it is safe to say n.
919 config X86_THERMAL_VECTOR
921 depends on X86_MCE_INTEL
924 bool "Enable VM86 support" if EXPERT
928 This option is required by programs like DOSEMU to run 16-bit legacy
929 code on X86 processors. It also may be needed by software like
930 XFree86 to initialize some video cards via BIOS. Disabling this
931 option saves about 6k.
934 tristate "Toshiba Laptop support"
937 This adds a driver to safely access the System Management Mode of
938 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
939 not work on models with a Phoenix BIOS. The System Management Mode
940 is used to set the BIOS and power saving options on Toshiba portables.
942 For information on utilities to make use of this driver see the
943 Toshiba Linux utilities web site at:
944 <http://www.buzzard.org.uk/toshiba/>.
946 Say Y if you intend to run this kernel on a Toshiba portable.
950 tristate "Dell laptop support"
953 This adds a driver to safely access the System Management Mode
954 of the CPU on the Dell Inspiron 8000. The System Management Mode
955 is used to read cpu temperature and cooling fan status and to
956 control the fans on the I8K portables.
958 This driver has been tested only on the Inspiron 8000 but it may
959 also work with other Dell laptops. You can force loading on other
960 models by passing the parameter `force=1' to the module. Use at
963 For information on utilities to make use of this driver see the
964 I8K Linux utilities web site at:
965 <http://people.debian.org/~dz/i8k/>
967 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
970 config X86_REBOOTFIXUPS
971 bool "Enable X86 board specific fixups for reboot"
974 This enables chipset and/or board specific fixups to be done
975 in order to get reboot to work correctly. This is only needed on
976 some combinations of hardware and BIOS. The symptom, for which
977 this config is intended, is when reboot ends with a stalled/hung
980 Currently, the only fixup is for the Geode machines using
981 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
983 Say Y if you want to enable the fixup. Currently, it's safe to
984 enable this option even if you don't need it.
988 tristate "CPU microcode loading support"
992 If you say Y here, you will be able to update the microcode on
993 certain Intel and AMD processors. The Intel support is for the
994 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
995 Xeon etc. The AMD support is for families 0x10 and later. You will
996 obviously need the actual microcode binary data itself which is not
997 shipped with the Linux kernel.
999 This option selects the general module only, you need to select
1000 at least one vendor specific module as well.
1002 To compile this driver as a module, choose M here: the module
1003 will be called microcode.
1005 config MICROCODE_INTEL
1006 bool "Intel microcode loading support"
1007 depends on MICROCODE
1011 This options enables microcode patch loading support for Intel
1014 For latest news and information on obtaining all the required
1015 Intel ingredients for this driver, check:
1016 <http://www.urbanmyth.org/microcode/>.
1018 config MICROCODE_AMD
1019 bool "AMD microcode loading support"
1020 depends on MICROCODE
1023 If you select this option, microcode patch loading support for AMD
1024 processors will be enabled.
1026 config MICROCODE_OLD_INTERFACE
1028 depends on MICROCODE
1031 tristate "/dev/cpu/*/msr - Model-specific register support"
1033 This device gives privileged processes access to the x86
1034 Model-Specific Registers (MSRs). It is a character device with
1035 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1036 MSR accesses are directed to a specific CPU on multi-processor
1040 tristate "/dev/cpu/*/cpuid - CPU information support"
1042 This device gives processes access to the x86 CPUID instruction to
1043 be executed on a specific processor. It is a character device
1044 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1048 prompt "High Memory Support"
1049 default HIGHMEM64G if X86_NUMAQ
1055 depends on !X86_NUMAQ
1057 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1058 However, the address space of 32-bit x86 processors is only 4
1059 Gigabytes large. That means that, if you have a large amount of
1060 physical memory, not all of it can be "permanently mapped" by the
1061 kernel. The physical memory that's not permanently mapped is called
1064 If you are compiling a kernel which will never run on a machine with
1065 more than 1 Gigabyte total physical RAM, answer "off" here (default
1066 choice and suitable for most users). This will result in a "3GB/1GB"
1067 split: 3GB are mapped so that each process sees a 3GB virtual memory
1068 space and the remaining part of the 4GB virtual memory space is used
1069 by the kernel to permanently map as much physical memory as
1072 If the machine has between 1 and 4 Gigabytes physical RAM, then
1075 If more than 4 Gigabytes is used then answer "64GB" here. This
1076 selection turns Intel PAE (Physical Address Extension) mode on.
1077 PAE implements 3-level paging on IA32 processors. PAE is fully
1078 supported by Linux, PAE mode is implemented on all recent Intel
1079 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1080 then the kernel will not boot on CPUs that don't support PAE!
1082 The actual amount of total physical memory will either be
1083 auto detected or can be forced by using a kernel command line option
1084 such as "mem=256M". (Try "man bootparam" or see the documentation of
1085 your boot loader (lilo or loadlin) about how to pass options to the
1086 kernel at boot time.)
1088 If unsure, say "off".
1092 depends on !X86_NUMAQ
1094 Select this if you have a 32-bit processor and between 1 and 4
1095 gigabytes of physical RAM.
1102 Select this if you have a 32-bit processor and more than 4
1103 gigabytes of physical RAM.
1108 depends on EXPERIMENTAL
1109 prompt "Memory split" if EXPERT
1113 Select the desired split between kernel and user memory.
1115 If the address range available to the kernel is less than the
1116 physical memory installed, the remaining memory will be available
1117 as "high memory". Accessing high memory is a little more costly
1118 than low memory, as it needs to be mapped into the kernel first.
1119 Note that increasing the kernel address space limits the range
1120 available to user programs, making the address space there
1121 tighter. Selecting anything other than the default 3G/1G split
1122 will also likely make your kernel incompatible with binary-only
1125 If you are not absolutely sure what you are doing, leave this
1129 bool "3G/1G user/kernel split"
1130 config VMSPLIT_3G_OPT
1132 bool "3G/1G user/kernel split (for full 1G low memory)"
1134 bool "2G/2G user/kernel split"
1135 config VMSPLIT_2G_OPT
1137 bool "2G/2G user/kernel split (for full 2G low memory)"
1139 bool "1G/3G user/kernel split"
1144 default 0xB0000000 if VMSPLIT_3G_OPT
1145 default 0x80000000 if VMSPLIT_2G
1146 default 0x78000000 if VMSPLIT_2G_OPT
1147 default 0x40000000 if VMSPLIT_1G
1153 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1156 bool "PAE (Physical Address Extension) Support"
1157 depends on X86_32 && !HIGHMEM4G
1159 PAE is required for NX support, and furthermore enables
1160 larger swapspace support for non-overcommit purposes. It
1161 has the cost of more pagetable lookup overhead, and also
1162 consumes more pagetable space per process.
1164 config ARCH_PHYS_ADDR_T_64BIT
1166 depends on X86_64 || X86_PAE
1168 config ARCH_DMA_ADDR_T_64BIT
1170 depends on X86_64 || HIGHMEM64G
1172 config DIRECT_GBPAGES
1173 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1177 Allow the kernel linear mapping to use 1GB pages on CPUs that
1178 support it. This can improve the kernel's performance a tiny bit by
1179 reducing TLB pressure. If in doubt, say "Y".
1181 # Common NUMA Features
1183 bool "Numa Memory Allocation and Scheduler Support"
1185 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1186 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1188 Enable NUMA (Non Uniform Memory Access) support.
1190 The kernel will try to allocate memory used by a CPU on the
1191 local memory controller of the CPU and add some more
1192 NUMA awareness to the kernel.
1194 For 64-bit this is recommended if the system is Intel Core i7
1195 (or later), AMD Opteron, or EM64T NUMA.
1197 For 32-bit this is only needed on (rare) 32-bit-only platforms
1198 that support NUMA topologies, such as NUMAQ / Summit, or if you
1199 boot a 32-bit kernel on a 64-bit NUMA platform.
1201 Otherwise, you should say N.
1203 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1204 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1208 prompt "Old style AMD Opteron NUMA detection"
1209 depends on X86_64 && NUMA && PCI
1211 Enable AMD NUMA node topology detection. You should say Y here if
1212 you have a multi processor AMD system. This uses an old method to
1213 read the NUMA configuration directly from the builtin Northbridge
1214 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1215 which also takes priority if both are compiled in.
1217 config X86_64_ACPI_NUMA
1219 prompt "ACPI NUMA detection"
1220 depends on X86_64 && NUMA && ACPI && PCI
1223 Enable ACPI SRAT based node topology detection.
1225 # Some NUMA nodes have memory ranges that span
1226 # other nodes. Even though a pfn is valid and
1227 # between a node's start and end pfns, it may not
1228 # reside on that node. See memmap_init_zone()
1230 config NODES_SPAN_OTHER_NODES
1232 depends on X86_64_ACPI_NUMA
1235 bool "NUMA emulation"
1238 Enable NUMA emulation. A flat machine will be split
1239 into virtual nodes when booted with "numa=fake=N", where N is the
1240 number of nodes. This is only useful for debugging.
1243 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1245 default "10" if MAXSMP
1246 default "6" if X86_64
1247 default "4" if X86_NUMAQ
1249 depends on NEED_MULTIPLE_NODES
1251 Specify the maximum number of NUMA Nodes available on the target
1252 system. Increases memory reserved to accommodate various tables.
1254 config HAVE_ARCH_ALLOC_REMAP
1256 depends on X86_32 && NUMA
1258 config ARCH_HAVE_MEMORY_PRESENT
1260 depends on X86_32 && DISCONTIGMEM
1262 config NEED_NODE_MEMMAP_SIZE
1264 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1266 config ARCH_FLATMEM_ENABLE
1268 depends on X86_32 && !NUMA
1270 config ARCH_DISCONTIGMEM_ENABLE
1272 depends on NUMA && X86_32
1274 config ARCH_DISCONTIGMEM_DEFAULT
1276 depends on NUMA && X86_32
1278 config ARCH_SPARSEMEM_ENABLE
1280 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1281 select SPARSEMEM_STATIC if X86_32
1282 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1284 config ARCH_SPARSEMEM_DEFAULT
1288 config ARCH_SELECT_MEMORY_MODEL
1290 depends on ARCH_SPARSEMEM_ENABLE
1292 config ARCH_MEMORY_PROBE
1294 depends on X86_64 && MEMORY_HOTPLUG
1296 config ARCH_PROC_KCORE_TEXT
1298 depends on X86_64 && PROC_KCORE
1300 config ILLEGAL_POINTER_VALUE
1303 default 0xdead000000000000 if X86_64
1308 bool "Allocate 3rd-level pagetables from highmem"
1311 The VM uses one page table entry for each page of physical memory.
1312 For systems with a lot of RAM, this can be wasteful of precious
1313 low memory. Setting this option will put user-space page table
1314 entries in high memory.
1316 config X86_CHECK_BIOS_CORRUPTION
1317 bool "Check for low memory corruption"
1319 Periodically check for memory corruption in low memory, which
1320 is suspected to be caused by BIOS. Even when enabled in the
1321 configuration, it is disabled at runtime. Enable it by
1322 setting "memory_corruption_check=1" on the kernel command
1323 line. By default it scans the low 64k of memory every 60
1324 seconds; see the memory_corruption_check_size and
1325 memory_corruption_check_period parameters in
1326 Documentation/kernel-parameters.txt to adjust this.
1328 When enabled with the default parameters, this option has
1329 almost no overhead, as it reserves a relatively small amount
1330 of memory and scans it infrequently. It both detects corruption
1331 and prevents it from affecting the running system.
1333 It is, however, intended as a diagnostic tool; if repeatable
1334 BIOS-originated corruption always affects the same memory,
1335 you can use memmap= to prevent the kernel from using that
1338 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1339 bool "Set the default setting of memory_corruption_check"
1340 depends on X86_CHECK_BIOS_CORRUPTION
1343 Set whether the default state of memory_corruption_check is
1346 config X86_RESERVE_LOW
1347 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1351 Specify the amount of low memory to reserve for the BIOS.
1353 The first page contains BIOS data structures that the kernel
1354 must not use, so that page must always be reserved.
1356 By default we reserve the first 64K of physical RAM, as a
1357 number of BIOSes are known to corrupt that memory range
1358 during events such as suspend/resume or monitor cable
1359 insertion, so it must not be used by the kernel.
1361 You can set this to 4 if you are absolutely sure that you
1362 trust the BIOS to get all its memory reservations and usages
1363 right. If you know your BIOS have problems beyond the
1364 default 64K area, you can set this to 640 to avoid using the
1365 entire low memory range.
1367 If you have doubts about the BIOS (e.g. suspend/resume does
1368 not work or there's kernel crashes after certain hardware
1369 hotplug events) then you might want to enable
1370 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1371 typical corruption patterns.
1373 Leave this to the default value of 64 if you are unsure.
1375 config MATH_EMULATION
1377 prompt "Math emulation" if X86_32
1379 Linux can emulate a math coprocessor (used for floating point
1380 operations) if you don't have one. 486DX and Pentium processors have
1381 a math coprocessor built in, 486SX and 386 do not, unless you added
1382 a 487DX or 387, respectively. (The messages during boot time can
1383 give you some hints here ["man dmesg"].) Everyone needs either a
1384 coprocessor or this emulation.
1386 If you don't have a math coprocessor, you need to say Y here; if you
1387 say Y here even though you have a coprocessor, the coprocessor will
1388 be used nevertheless. (This behavior can be changed with the kernel
1389 command line option "no387", which comes handy if your coprocessor
1390 is broken. Try "man bootparam" or see the documentation of your boot
1391 loader (lilo or loadlin) about how to pass options to the kernel at
1392 boot time.) This means that it is a good idea to say Y here if you
1393 intend to use this kernel on different machines.
1395 More information about the internals of the Linux math coprocessor
1396 emulation can be found in <file:arch/x86/math-emu/README>.
1398 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1399 kernel, it won't hurt.
1403 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1405 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1406 the Memory Type Range Registers (MTRRs) may be used to control
1407 processor access to memory ranges. This is most useful if you have
1408 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1409 allows bus write transfers to be combined into a larger transfer
1410 before bursting over the PCI/AGP bus. This can increase performance
1411 of image write operations 2.5 times or more. Saying Y here creates a
1412 /proc/mtrr file which may be used to manipulate your processor's
1413 MTRRs. Typically the X server should use this.
1415 This code has a reasonably generic interface so that similar
1416 control registers on other processors can be easily supported
1419 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1420 Registers (ARRs) which provide a similar functionality to MTRRs. For
1421 these, the ARRs are used to emulate the MTRRs.
1422 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1423 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1424 write-combining. All of these processors are supported by this code
1425 and it makes sense to say Y here if you have one of them.
1427 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1428 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1429 can lead to all sorts of problems, so it's good to say Y here.
1431 You can safely say Y even if your machine doesn't have MTRRs, you'll
1432 just add about 9 KB to your kernel.
1434 See <file:Documentation/x86/mtrr.txt> for more information.
1436 config MTRR_SANITIZER
1438 prompt "MTRR cleanup support"
1441 Convert MTRR layout from continuous to discrete, so X drivers can
1442 add writeback entries.
1444 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1445 The largest mtrr entry size for a continuous block can be set with
1450 config MTRR_SANITIZER_ENABLE_DEFAULT
1451 int "MTRR cleanup enable value (0-1)"
1454 depends on MTRR_SANITIZER
1456 Enable mtrr cleanup default value
1458 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1459 int "MTRR cleanup spare reg num (0-7)"
1462 depends on MTRR_SANITIZER
1464 mtrr cleanup spare entries default, it can be changed via
1465 mtrr_spare_reg_nr=N on the kernel command line.
1469 prompt "x86 PAT support" if EXPERT
1472 Use PAT attributes to setup page level cache control.
1474 PATs are the modern equivalents of MTRRs and are much more
1475 flexible than MTRRs.
1477 Say N here if you see bootup problems (boot crash, boot hang,
1478 spontaneous reboots) or a non-working video driver.
1482 config ARCH_USES_PG_UNCACHED
1488 prompt "x86 architectural random number generator" if EXPERT
1490 Enable the x86 architectural RDRAND instruction
1491 (Intel Bull Mountain technology) to generate random numbers.
1492 If supported, this is a high bandwidth, cryptographically
1493 secure hardware random number generator.
1497 prompt "Supervisor Mode Access Prevention" if EXPERT
1499 Supervisor Mode Access Prevention (SMAP) is a security
1500 feature in newer Intel processors. There is a small
1501 performance cost if this enabled and turned on; there is
1502 also a small increase in the kernel size if this is enabled.
1507 bool "EFI runtime service support"
1510 This enables the kernel to use EFI runtime services that are
1511 available (such as the EFI variable services).
1513 This option is only useful on systems that have EFI firmware.
1514 In addition, you should use the latest ELILO loader available
1515 at <http://elilo.sourceforge.net> in order to take advantage
1516 of EFI runtime services. However, even with this option, the
1517 resultant kernel should continue to boot on existing non-EFI
1521 bool "EFI stub support"
1524 This kernel feature allows a bzImage to be loaded directly
1525 by EFI firmware without the use of a bootloader.
1527 See Documentation/x86/efi-stub.txt for more information.
1531 prompt "Enable seccomp to safely compute untrusted bytecode"
1533 This kernel feature is useful for number crunching applications
1534 that may need to compute untrusted bytecode during their
1535 execution. By using pipes or other transports made available to
1536 the process as file descriptors supporting the read/write
1537 syscalls, it's possible to isolate those applications in
1538 their own address space using seccomp. Once seccomp is
1539 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1540 and the task is only allowed to execute a few safe syscalls
1541 defined by each seccomp mode.
1543 If unsure, say Y. Only embedded should say N here.
1545 config CC_STACKPROTECTOR
1546 bool "Enable -fstack-protector buffer overflow detection"
1548 This option turns on the -fstack-protector GCC feature. This
1549 feature puts, at the beginning of functions, a canary value on
1550 the stack just before the return address, and validates
1551 the value just before actually returning. Stack based buffer
1552 overflows (that need to overwrite this return address) now also
1553 overwrite the canary, which gets detected and the attack is then
1554 neutralized via a kernel panic.
1556 This feature requires gcc version 4.2 or above, or a distribution
1557 gcc with the feature backported. Older versions are automatically
1558 detected and for those versions, this configuration option is
1559 ignored. (and a warning is printed during bootup)
1561 source kernel/Kconfig.hz
1564 bool "kexec system call"
1566 kexec is a system call that implements the ability to shutdown your
1567 current kernel, and to start another kernel. It is like a reboot
1568 but it is independent of the system firmware. And like a reboot
1569 you can start any kernel with it, not just Linux.
1571 The name comes from the similarity to the exec system call.
1573 It is an ongoing process to be certain the hardware in a machine
1574 is properly shutdown, so do not be surprised if this code does not
1575 initially work for you. It may help to enable device hotplugging
1576 support. As of this writing the exact hardware interface is
1577 strongly in flux, so no good recommendation can be made.
1580 bool "kernel crash dumps"
1581 depends on X86_64 || (X86_32 && HIGHMEM)
1583 Generate crash dump after being started by kexec.
1584 This should be normally only set in special crash dump kernels
1585 which are loaded in the main kernel with kexec-tools into
1586 a specially reserved region and then later executed after
1587 a crash by kdump/kexec. The crash dump kernel must be compiled
1588 to a memory address not used by the main kernel or BIOS using
1589 PHYSICAL_START, or it must be built as a relocatable image
1590 (CONFIG_RELOCATABLE=y).
1591 For more details see Documentation/kdump/kdump.txt
1594 bool "kexec jump (EXPERIMENTAL)"
1595 depends on EXPERIMENTAL
1596 depends on KEXEC && HIBERNATION
1598 Jump between original kernel and kexeced kernel and invoke
1599 code in physical address mode via KEXEC
1601 config PHYSICAL_START
1602 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1605 This gives the physical address where the kernel is loaded.
1607 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1608 bzImage will decompress itself to above physical address and
1609 run from there. Otherwise, bzImage will run from the address where
1610 it has been loaded by the boot loader and will ignore above physical
1613 In normal kdump cases one does not have to set/change this option
1614 as now bzImage can be compiled as a completely relocatable image
1615 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1616 address. This option is mainly useful for the folks who don't want
1617 to use a bzImage for capturing the crash dump and want to use a
1618 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1619 to be specifically compiled to run from a specific memory area
1620 (normally a reserved region) and this option comes handy.
1622 So if you are using bzImage for capturing the crash dump,
1623 leave the value here unchanged to 0x1000000 and set
1624 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1625 for capturing the crash dump change this value to start of
1626 the reserved region. In other words, it can be set based on
1627 the "X" value as specified in the "crashkernel=YM@XM"
1628 command line boot parameter passed to the panic-ed
1629 kernel. Please take a look at Documentation/kdump/kdump.txt
1630 for more details about crash dumps.
1632 Usage of bzImage for capturing the crash dump is recommended as
1633 one does not have to build two kernels. Same kernel can be used
1634 as production kernel and capture kernel. Above option should have
1635 gone away after relocatable bzImage support is introduced. But it
1636 is present because there are users out there who continue to use
1637 vmlinux for dump capture. This option should go away down the
1640 Don't change this unless you know what you are doing.
1643 bool "Build a relocatable kernel"
1646 This builds a kernel image that retains relocation information
1647 so it can be loaded someplace besides the default 1MB.
1648 The relocations tend to make the kernel binary about 10% larger,
1649 but are discarded at runtime.
1651 One use is for the kexec on panic case where the recovery kernel
1652 must live at a different physical address than the primary
1655 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1656 it has been loaded at and the compile time physical address
1657 (CONFIG_PHYSICAL_START) is ignored.
1659 # Relocation on x86-32 needs some additional build support
1660 config X86_NEED_RELOCS
1662 depends on X86_32 && RELOCATABLE
1664 config PHYSICAL_ALIGN
1665 hex "Alignment value to which kernel should be aligned" if X86_32
1667 range 0x2000 0x1000000
1669 This value puts the alignment restrictions on physical address
1670 where kernel is loaded and run from. Kernel is compiled for an
1671 address which meets above alignment restriction.
1673 If bootloader loads the kernel at a non-aligned address and
1674 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1675 address aligned to above value and run from there.
1677 If bootloader loads the kernel at a non-aligned address and
1678 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1679 load address and decompress itself to the address it has been
1680 compiled for and run from there. The address for which kernel is
1681 compiled already meets above alignment restrictions. Hence the
1682 end result is that kernel runs from a physical address meeting
1683 above alignment restrictions.
1685 Don't change this unless you know what you are doing.
1688 bool "Support for hot-pluggable CPUs"
1689 depends on SMP && HOTPLUG
1691 Say Y here to allow turning CPUs off and on. CPUs can be
1692 controlled through /sys/devices/system/cpu.
1693 ( Note: power management support will enable this option
1694 automatically on SMP systems. )
1695 Say N if you want to disable CPU hotplug.
1697 config BOOTPARAM_HOTPLUG_CPU0
1698 bool "Set default setting of cpu0_hotpluggable"
1700 depends on HOTPLUG_CPU && EXPERIMENTAL
1702 Set whether default state of cpu0_hotpluggable is on or off.
1704 Say Y here to enable CPU0 hotplug by default. If this switch
1705 is turned on, there is no need to give cpu0_hotplug kernel
1706 parameter and the CPU0 hotplug feature is enabled by default.
1708 Please note: there are two known CPU0 dependencies if you want
1709 to enable the CPU0 hotplug feature either by this switch or by
1710 cpu0_hotplug kernel parameter.
1712 First, resume from hibernate or suspend always starts from CPU0.
1713 So hibernate and suspend are prevented if CPU0 is offline.
1715 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1716 offline if any interrupt can not migrate out of CPU0. There may
1717 be other CPU0 dependencies.
1719 Please make sure the dependencies are under your control before
1720 you enable this feature.
1722 Say N if you don't want to enable CPU0 hotplug feature by default.
1723 You still can enable the CPU0 hotplug feature at boot by kernel
1724 parameter cpu0_hotplug.
1726 config DEBUG_HOTPLUG_CPU0
1728 prompt "Debug CPU0 hotplug"
1729 depends on HOTPLUG_CPU && EXPERIMENTAL
1731 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1732 soon as possible and boots up userspace with CPU0 offlined. User
1733 can online CPU0 back after boot time.
1735 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1736 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1737 compilation or giving cpu0_hotplug kernel parameter at boot.
1743 prompt "Compat VDSO support"
1744 depends on X86_32 || IA32_EMULATION
1746 Map the 32-bit VDSO to the predictable old-style address too.
1748 Say N here if you are running a sufficiently recent glibc
1749 version (2.3.3 or later), to remove the high-mapped
1750 VDSO mapping and to exclusively use the randomized VDSO.
1755 bool "Built-in kernel command line"
1757 Allow for specifying boot arguments to the kernel at
1758 build time. On some systems (e.g. embedded ones), it is
1759 necessary or convenient to provide some or all of the
1760 kernel boot arguments with the kernel itself (that is,
1761 to not rely on the boot loader to provide them.)
1763 To compile command line arguments into the kernel,
1764 set this option to 'Y', then fill in the
1765 the boot arguments in CONFIG_CMDLINE.
1767 Systems with fully functional boot loaders (i.e. non-embedded)
1768 should leave this option set to 'N'.
1771 string "Built-in kernel command string"
1772 depends on CMDLINE_BOOL
1775 Enter arguments here that should be compiled into the kernel
1776 image and used at boot time. If the boot loader provides a
1777 command line at boot time, it is appended to this string to
1778 form the full kernel command line, when the system boots.
1780 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1781 change this behavior.
1783 In most cases, the command line (whether built-in or provided
1784 by the boot loader) should specify the device for the root
1787 config CMDLINE_OVERRIDE
1788 bool "Built-in command line overrides boot loader arguments"
1789 depends on CMDLINE_BOOL
1791 Set this option to 'Y' to have the kernel ignore the boot loader
1792 command line, and use ONLY the built-in command line.
1794 This is used to work around broken boot loaders. This should
1795 be set to 'N' under normal conditions.
1799 config ARCH_ENABLE_MEMORY_HOTPLUG
1801 depends on X86_64 || (X86_32 && HIGHMEM)
1803 config ARCH_ENABLE_MEMORY_HOTREMOVE
1805 depends on MEMORY_HOTPLUG
1807 config USE_PERCPU_NUMA_NODE_ID
1811 menu "Power management and ACPI options"
1813 config ARCH_HIBERNATION_HEADER
1815 depends on X86_64 && HIBERNATION
1817 source "kernel/power/Kconfig"
1819 source "drivers/acpi/Kconfig"
1821 source "drivers/sfi/Kconfig"
1828 tristate "APM (Advanced Power Management) BIOS support"
1829 depends on X86_32 && PM_SLEEP
1831 APM is a BIOS specification for saving power using several different
1832 techniques. This is mostly useful for battery powered laptops with
1833 APM compliant BIOSes. If you say Y here, the system time will be
1834 reset after a RESUME operation, the /proc/apm device will provide
1835 battery status information, and user-space programs will receive
1836 notification of APM "events" (e.g. battery status change).
1838 If you select "Y" here, you can disable actual use of the APM
1839 BIOS by passing the "apm=off" option to the kernel at boot time.
1841 Note that the APM support is almost completely disabled for
1842 machines with more than one CPU.
1844 In order to use APM, you will need supporting software. For location
1845 and more information, read <file:Documentation/power/apm-acpi.txt>
1846 and the Battery Powered Linux mini-HOWTO, available from
1847 <http://www.tldp.org/docs.html#howto>.
1849 This driver does not spin down disk drives (see the hdparm(8)
1850 manpage ("man 8 hdparm") for that), and it doesn't turn off
1851 VESA-compliant "green" monitors.
1853 This driver does not support the TI 4000M TravelMate and the ACER
1854 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1855 desktop machines also don't have compliant BIOSes, and this driver
1856 may cause those machines to panic during the boot phase.
1858 Generally, if you don't have a battery in your machine, there isn't
1859 much point in using this driver and you should say N. If you get
1860 random kernel OOPSes or reboots that don't seem to be related to
1861 anything, try disabling/enabling this option (or disabling/enabling
1864 Some other things you should try when experiencing seemingly random,
1867 1) make sure that you have enough swap space and that it is
1869 2) pass the "no-hlt" option to the kernel
1870 3) switch on floating point emulation in the kernel and pass
1871 the "no387" option to the kernel
1872 4) pass the "floppy=nodma" option to the kernel
1873 5) pass the "mem=4M" option to the kernel (thereby disabling
1874 all but the first 4 MB of RAM)
1875 6) make sure that the CPU is not over clocked.
1876 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1877 8) disable the cache from your BIOS settings
1878 9) install a fan for the video card or exchange video RAM
1879 10) install a better fan for the CPU
1880 11) exchange RAM chips
1881 12) exchange the motherboard.
1883 To compile this driver as a module, choose M here: the
1884 module will be called apm.
1888 config APM_IGNORE_USER_SUSPEND
1889 bool "Ignore USER SUSPEND"
1891 This option will ignore USER SUSPEND requests. On machines with a
1892 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1893 series notebooks, it is necessary to say Y because of a BIOS bug.
1895 config APM_DO_ENABLE
1896 bool "Enable PM at boot time"
1898 Enable APM features at boot time. From page 36 of the APM BIOS
1899 specification: "When disabled, the APM BIOS does not automatically
1900 power manage devices, enter the Standby State, enter the Suspend
1901 State, or take power saving steps in response to CPU Idle calls."
1902 This driver will make CPU Idle calls when Linux is idle (unless this
1903 feature is turned off -- see "Do CPU IDLE calls", below). This
1904 should always save battery power, but more complicated APM features
1905 will be dependent on your BIOS implementation. You may need to turn
1906 this option off if your computer hangs at boot time when using APM
1907 support, or if it beeps continuously instead of suspending. Turn
1908 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1909 T400CDT. This is off by default since most machines do fine without
1913 bool "Make CPU Idle calls when idle"
1915 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1916 On some machines, this can activate improved power savings, such as
1917 a slowed CPU clock rate, when the machine is idle. These idle calls
1918 are made after the idle loop has run for some length of time (e.g.,
1919 333 mS). On some machines, this will cause a hang at boot time or
1920 whenever the CPU becomes idle. (On machines with more than one CPU,
1921 this option does nothing.)
1923 config APM_DISPLAY_BLANK
1924 bool "Enable console blanking using APM"
1926 Enable console blanking using the APM. Some laptops can use this to
1927 turn off the LCD backlight when the screen blanker of the Linux
1928 virtual console blanks the screen. Note that this is only used by
1929 the virtual console screen blanker, and won't turn off the backlight
1930 when using the X Window system. This also doesn't have anything to
1931 do with your VESA-compliant power-saving monitor. Further, this
1932 option doesn't work for all laptops -- it might not turn off your
1933 backlight at all, or it might print a lot of errors to the console,
1934 especially if you are using gpm.
1936 config APM_ALLOW_INTS
1937 bool "Allow interrupts during APM BIOS calls"
1939 Normally we disable external interrupts while we are making calls to
1940 the APM BIOS as a measure to lessen the effects of a badly behaving
1941 BIOS implementation. The BIOS should reenable interrupts if it
1942 needs to. Unfortunately, some BIOSes do not -- especially those in
1943 many of the newer IBM Thinkpads. If you experience hangs when you
1944 suspend, try setting this to Y. Otherwise, say N.
1948 source "drivers/cpufreq/Kconfig"
1950 source "drivers/cpuidle/Kconfig"
1952 source "drivers/idle/Kconfig"
1957 menu "Bus options (PCI etc.)"
1962 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1964 Find out whether you have a PCI motherboard. PCI is the name of a
1965 bus system, i.e. the way the CPU talks to the other stuff inside
1966 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1967 VESA. If you have PCI, say Y, otherwise N.
1970 prompt "PCI access mode"
1971 depends on X86_32 && PCI
1974 On PCI systems, the BIOS can be used to detect the PCI devices and
1975 determine their configuration. However, some old PCI motherboards
1976 have BIOS bugs and may crash if this is done. Also, some embedded
1977 PCI-based systems don't have any BIOS at all. Linux can also try to
1978 detect the PCI hardware directly without using the BIOS.
1980 With this option, you can specify how Linux should detect the
1981 PCI devices. If you choose "BIOS", the BIOS will be used,
1982 if you choose "Direct", the BIOS won't be used, and if you
1983 choose "MMConfig", then PCI Express MMCONFIG will be used.
1984 If you choose "Any", the kernel will try MMCONFIG, then the
1985 direct access method and falls back to the BIOS if that doesn't
1986 work. If unsure, go with the default, which is "Any".
1991 config PCI_GOMMCONFIG
2008 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2010 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2013 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2017 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2021 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2025 depends on PCI && XEN
2033 bool "Support mmconfig PCI config space access"
2034 depends on X86_64 && PCI && ACPI
2036 config PCI_CNB20LE_QUIRK
2037 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2038 depends on PCI && EXPERIMENTAL
2040 Read the PCI windows out of the CNB20LE host bridge. This allows
2041 PCI hotplug to work on systems with the CNB20LE chipset which do
2044 There's no public spec for this chipset, and this functionality
2045 is known to be incomplete.
2047 You should say N unless you know you need this.
2049 source "drivers/pci/pcie/Kconfig"
2051 source "drivers/pci/Kconfig"
2053 # x86_64 have no ISA slots, but can have ISA-style DMA.
2055 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2058 Enables ISA-style DMA support for devices requiring such controllers.
2066 Find out whether you have ISA slots on your motherboard. ISA is the
2067 name of a bus system, i.e. the way the CPU talks to the other stuff
2068 inside your box. Other bus systems are PCI, EISA, MicroChannel
2069 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2070 newer boards don't support it. If you have ISA, say Y, otherwise N.
2076 The Extended Industry Standard Architecture (EISA) bus was
2077 developed as an open alternative to the IBM MicroChannel bus.
2079 The EISA bus provided some of the features of the IBM MicroChannel
2080 bus while maintaining backward compatibility with cards made for
2081 the older ISA bus. The EISA bus saw limited use between 1988 and
2082 1995 when it was made obsolete by the PCI bus.
2084 Say Y here if you are building a kernel for an EISA-based machine.
2088 source "drivers/eisa/Kconfig"
2091 tristate "NatSemi SCx200 support"
2093 This provides basic support for National Semiconductor's
2094 (now AMD's) Geode processors. The driver probes for the
2095 PCI-IDs of several on-chip devices, so its a good dependency
2096 for other scx200_* drivers.
2098 If compiled as a module, the driver is named scx200.
2100 config SCx200HR_TIMER
2101 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2105 This driver provides a clocksource built upon the on-chip
2106 27MHz high-resolution timer. Its also a workaround for
2107 NSC Geode SC-1100's buggy TSC, which loses time when the
2108 processor goes idle (as is done by the scheduler). The
2109 other workaround is idle=poll boot option.
2112 bool "One Laptop Per Child support"
2119 Add support for detecting the unique features of the OLPC
2123 bool "OLPC XO-1 Power Management"
2124 depends on OLPC && MFD_CS5535 && PM_SLEEP
2127 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2130 bool "OLPC XO-1 Real Time Clock"
2131 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2133 Add support for the XO-1 real time clock, which can be used as a
2134 programmable wakeup source.
2137 bool "OLPC XO-1 SCI extras"
2138 depends on OLPC && OLPC_XO1_PM
2143 Add support for SCI-based features of the OLPC XO-1 laptop:
2144 - EC-driven system wakeups
2148 - AC adapter status updates
2149 - Battery status updates
2151 config OLPC_XO15_SCI
2152 bool "OLPC XO-1.5 SCI extras"
2153 depends on OLPC && ACPI
2156 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2157 - EC-driven system wakeups
2158 - AC adapter status updates
2159 - Battery status updates
2162 bool "PCEngines ALIX System Support (LED setup)"
2165 This option enables system support for the PCEngines ALIX.
2166 At present this just sets up LEDs for GPIO control on
2167 ALIX2/3/6 boards. However, other system specific setup should
2170 Note: You must still enable the drivers for GPIO and LED support
2171 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2173 Note: You have to set alix.force=1 for boards with Award BIOS.
2176 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2179 This option enables system support for the Soekris Engineering net5501.
2182 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2186 This option enables system support for the Traverse Technologies GEOS.
2192 depends on CPU_SUP_AMD && PCI
2194 source "drivers/pcmcia/Kconfig"
2196 source "drivers/pci/hotplug/Kconfig"
2199 bool "RapidIO support"
2203 If you say Y here, the kernel will include drivers and
2204 infrastructure code to support RapidIO interconnect devices.
2206 source "drivers/rapidio/Kconfig"
2211 menu "Executable file formats / Emulations"
2213 source "fs/Kconfig.binfmt"
2215 config IA32_EMULATION
2216 bool "IA32 Emulation"
2218 select COMPAT_BINFMT_ELF
2221 Include code to run legacy 32-bit programs under a
2222 64-bit kernel. You should likely turn this on, unless you're
2223 100% sure that you don't have any 32-bit programs left.
2226 tristate "IA32 a.out support"
2227 depends on IA32_EMULATION
2229 Support old a.out binaries in the 32bit emulation.
2232 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2233 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2235 Include code to run binaries for the x32 native 32-bit ABI
2236 for 64-bit processors. An x32 process gets access to the
2237 full 64-bit register file and wide data path while leaving
2238 pointers at 32 bits for smaller memory footprint.
2240 You will need a recent binutils (2.22 or later) with
2241 elf32_x86_64 support enabled to compile a kernel with this
2246 depends on IA32_EMULATION || X86_X32
2247 select ARCH_WANT_OLD_COMPAT_IPC
2250 config COMPAT_FOR_U64_ALIGNMENT
2253 config SYSVIPC_COMPAT
2265 config HAVE_ATOMIC_IOMAP
2269 config HAVE_TEXT_POKE_SMP
2271 select STOP_MACHINE if SMP
2273 config X86_DEV_DMA_OPS
2275 depends on X86_64 || STA2X11
2277 config X86_DMA_REMAP
2281 source "net/Kconfig"
2283 source "drivers/Kconfig"
2285 source "drivers/firmware/Kconfig"
2289 source "arch/x86/Kconfig.debug"
2291 source "security/Kconfig"
2293 source "crypto/Kconfig"
2295 source "arch/x86/kvm/Kconfig"
2297 source "lib/Kconfig"
projects / can-eth-gw-linux.git / blob