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
25 select ARCH_SUPPORTS_NUMA_BALANCING
26 select ARCH_WANTS_PROT_NUMA_PROT_NONE
29 select HAVE_PCSPKR_PLATFORM
30 select HAVE_PERF_EVENTS
32 select HAVE_IOREMAP_PROT
35 select HAVE_MEMBLOCK_NODE_MAP
36 select ARCH_DISCARD_MEMBLOCK
37 select ARCH_WANT_OPTIONAL_GPIOLIB
38 select ARCH_WANT_FRAME_POINTERS
40 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
41 select HAVE_KRETPROBES
43 select HAVE_FTRACE_MCOUNT_RECORD
44 select HAVE_FENTRY if X86_64
45 select HAVE_C_RECORDMCOUNT
46 select HAVE_DYNAMIC_FTRACE
47 select HAVE_FUNCTION_TRACER
48 select HAVE_FUNCTION_GRAPH_TRACER
49 select HAVE_FUNCTION_GRAPH_FP_TEST
50 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
51 select HAVE_SYSCALL_TRACEPOINTS
52 select SYSCTL_EXCEPTION_TRACE
55 select HAVE_ARCH_TRACEHOOK
56 select HAVE_GENERIC_DMA_COHERENT if X86_32
57 select HAVE_EFFICIENT_UNALIGNED_ACCESS
58 select USER_STACKTRACE_SUPPORT
59 select HAVE_REGS_AND_STACK_ACCESS_API
60 select HAVE_DMA_API_DEBUG
61 select HAVE_KERNEL_GZIP
62 select HAVE_KERNEL_BZIP2
63 select HAVE_KERNEL_LZMA
65 select HAVE_KERNEL_LZO
66 select HAVE_HW_BREAKPOINT
67 select HAVE_MIXED_BREAKPOINTS_REGS
69 select HAVE_PERF_EVENTS_NMI
71 select HAVE_PERF_USER_STACK_DUMP
72 select HAVE_DEBUG_KMEMLEAK
74 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
75 select HAVE_CMPXCHG_LOCAL
76 select HAVE_CMPXCHG_DOUBLE
77 select HAVE_ARCH_KMEMCHECK
78 select HAVE_USER_RETURN_NOTIFIER
79 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
80 select HAVE_ARCH_JUMP_LABEL
81 select HAVE_TEXT_POKE_SMP
82 select HAVE_GENERIC_HARDIRQS
83 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
85 select GENERIC_FIND_FIRST_BIT
86 select GENERIC_IRQ_PROBE
87 select GENERIC_PENDING_IRQ if SMP
88 select GENERIC_IRQ_SHOW
89 select GENERIC_CLOCKEVENTS_MIN_ADJUST
90 select IRQ_FORCED_THREADING
91 select USE_GENERIC_SMP_HELPERS if SMP
92 select HAVE_BPF_JIT if X86_64
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
95 select ARCH_HAVE_NMI_SAFE_CMPXCHG
97 select DCACHE_WORD_ACCESS
98 select GENERIC_SMP_IDLE_THREAD
99 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
100 select HAVE_ARCH_SECCOMP_FILTER
101 select BUILDTIME_EXTABLE_SORT
102 select GENERIC_CMOS_UPDATE
103 select CLOCKSOURCE_WATCHDOG
104 select GENERIC_CLOCKEVENTS
105 select ARCH_CLOCKSOURCE_DATA if X86_64
106 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
107 select GENERIC_TIME_VSYSCALL if X86_64
108 select KTIME_SCALAR if X86_32
109 select GENERIC_STRNCPY_FROM_USER
110 select GENERIC_STRNLEN_USER
111 select HAVE_CONTEXT_TRACKING if X86_64
112 select HAVE_IRQ_TIME_ACCOUNTING
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
116 select GENERIC_SIGALTSTACK
118 config INSTRUCTION_DECODER
120 depends on KPROBES || PERF_EVENTS || UPROBES
124 default "elf32-i386" if X86_32
125 default "elf64-x86-64" if X86_64
127 config ARCH_DEFCONFIG
129 default "arch/x86/configs/i386_defconfig" if X86_32
130 default "arch/x86/configs/x86_64_defconfig" if X86_64
132 config LOCKDEP_SUPPORT
135 config STACKTRACE_SUPPORT
138 config HAVE_LATENCYTOP_SUPPORT
147 config NEED_DMA_MAP_STATE
149 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
151 config NEED_SG_DMA_LENGTH
154 config GENERIC_ISA_DMA
156 depends on ISA_DMA_API
161 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
163 config GENERIC_BUG_RELATIVE_POINTERS
166 config GENERIC_HWEIGHT
172 config ARCH_MAY_HAVE_PC_FDC
174 depends on ISA_DMA_API
176 config RWSEM_XCHGADD_ALGORITHM
179 config GENERIC_CALIBRATE_DELAY
182 config ARCH_HAS_CPU_RELAX
185 config ARCH_HAS_DEFAULT_IDLE
188 config ARCH_HAS_CACHE_LINE_SIZE
191 config ARCH_HAS_CPU_AUTOPROBE
194 config HAVE_SETUP_PER_CPU_AREA
197 config NEED_PER_CPU_EMBED_FIRST_CHUNK
200 config NEED_PER_CPU_PAGE_FIRST_CHUNK
203 config ARCH_HIBERNATION_POSSIBLE
206 config ARCH_SUSPEND_POSSIBLE
217 config ARCH_SUPPORTS_OPTIMIZED_INLINING
220 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
223 config HAVE_INTEL_TXT
225 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
229 depends on X86_32 && SMP
233 depends on X86_64 && SMP
239 config X86_32_LAZY_GS
241 depends on X86_32 && !CC_STACKPROTECTOR
243 config ARCH_HWEIGHT_CFLAGS
245 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
246 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
248 config ARCH_CPU_PROBE_RELEASE
250 depends on HOTPLUG_CPU
252 config ARCH_SUPPORTS_UPROBES
255 source "init/Kconfig"
256 source "kernel/Kconfig.freezer"
258 menu "Processor type and features"
261 bool "DMA memory allocation support" if EXPERT
264 DMA memory allocation support allows devices with less than 32-bit
265 addressing to allocate within the first 16MB of address space.
266 Disable if no such devices will be used.
271 bool "Symmetric multi-processing support"
273 This enables support for systems with more than one CPU. If you have
274 a system with only one CPU, like most personal computers, say N. If
275 you have a system with more than one CPU, say Y.
277 If you say N here, the kernel will run on single and multiprocessor
278 machines, but will use only one CPU of a multiprocessor machine. If
279 you say Y here, the kernel will run on many, but not all,
280 singleprocessor machines. On a singleprocessor machine, the kernel
281 will run faster if you say N here.
283 Note that if you say Y here and choose architecture "586" or
284 "Pentium" under "Processor family", the kernel will not work on 486
285 architectures. Similarly, multiprocessor kernels for the "PPro"
286 architecture may not work on all Pentium based boards.
288 People using multiprocessor machines who say Y here should also say
289 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
290 Management" code will be disabled if you say Y here.
292 See also <file:Documentation/x86/i386/IO-APIC.txt>,
293 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
294 <http://www.tldp.org/docs.html#howto>.
296 If you don't know what to do here, say N.
299 bool "Support x2apic"
300 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
302 This enables x2apic support on CPUs that have this feature.
304 This allows 32-bit apic IDs (so it can support very large systems),
305 and accesses the local apic via MSRs not via mmio.
307 If you don't know what to do here, say N.
310 bool "Enable MPS table" if ACPI || SFI
312 depends on X86_LOCAL_APIC
314 For old smp systems that do not have proper acpi support. Newer systems
315 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
318 bool "Support for big SMP systems with more than 8 CPUs"
319 depends on X86_32 && SMP
321 This option is needed for the systems that have more than 8 CPUs
324 config X86_EXTENDED_PLATFORM
325 bool "Support for extended (non-PC) x86 platforms"
328 If you disable this option then the kernel will only support
329 standard PC platforms. (which covers the vast majority of
332 If you enable this option then you'll be able to select support
333 for the following (non-PC) 32 bit x86 platforms:
337 SGI 320/540 (Visual Workstation)
338 STA2X11-based (e.g. Northville)
339 Summit/EXA (IBM x440)
340 Unisys ES7000 IA32 series
341 Moorestown MID devices
343 If you have one of these systems, or if you want to build a
344 generic distribution kernel, say Y here - otherwise say N.
348 config X86_EXTENDED_PLATFORM
349 bool "Support for extended (non-PC) x86 platforms"
352 If you disable this option then the kernel will only support
353 standard PC platforms. (which covers the vast majority of
356 If you enable this option then you'll be able to select support
357 for the following (non-PC) 64 bit x86 platforms:
362 If you have one of these systems, or if you want to build a
363 generic distribution kernel, say Y here - otherwise say N.
365 # This is an alphabetically sorted list of 64 bit extended platforms
366 # Please maintain the alphabetic order if and when there are additions
368 bool "Numascale NumaChip"
370 depends on X86_EXTENDED_PLATFORM
373 depends on X86_X2APIC
374 depends on PCI_MMCONFIG
376 Adds support for Numascale NumaChip large-SMP systems. Needed to
377 enable more than ~168 cores.
378 If you don't have one of these, you should say N here.
382 select PARAVIRT_GUEST
384 depends on X86_64 && PCI
385 depends on X86_EXTENDED_PLATFORM
388 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
389 supposed to run on these EM64T-based machines. Only choose this option
390 if you have one of these machines.
393 bool "SGI Ultraviolet"
395 depends on X86_EXTENDED_PLATFORM
397 depends on X86_X2APIC
399 This option is needed in order to support SGI Ultraviolet systems.
400 If you don't have one of these, you should say N here.
402 # Following is an alphabetically sorted list of 32 bit extended platforms
403 # Please maintain the alphabetic order if and when there are additions
406 bool "CE4100 TV platform"
408 depends on PCI_GODIRECT
410 depends on X86_EXTENDED_PLATFORM
411 select X86_REBOOTFIXUPS
413 select OF_EARLY_FLATTREE
416 Select for the Intel CE media processor (CE4100) SOC.
417 This option compiles in support for the CE4100 SOC for settop
418 boxes and media devices.
420 config X86_WANT_INTEL_MID
421 bool "Intel MID platform support"
423 depends on X86_EXTENDED_PLATFORM
425 Select to build a kernel capable of supporting Intel MID platform
426 systems which do not have the PCI legacy interfaces (Moorestown,
427 Medfield). If you are building for a PC class system say N here.
429 if X86_WANT_INTEL_MID
435 bool "Medfield MID platform"
438 depends on X86_IO_APIC
446 select X86_PLATFORM_DEVICES
447 select MFD_INTEL_MSIC
449 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
450 Internet Device(MID) platform.
451 Unlike standard x86 PCs, Medfield does not have many legacy devices
452 nor standard legacy replacement devices/features. e.g. Medfield does
453 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
457 config X86_INTEL_LPSS
458 bool "Intel Low Power Subsystem Support"
462 Select to build support for Intel Low Power Subsystem such as
463 found on Intel Lynxpoint PCH. Selecting this option enables
464 things like clock tree (common clock framework) which are needed
465 by the LPSS peripheral drivers.
468 bool "RDC R-321x SoC"
470 depends on X86_EXTENDED_PLATFORM
472 select X86_REBOOTFIXUPS
474 This option is needed for RDC R-321x system-on-chip, also known
476 If you don't have one of these chips, you should say N here.
478 config X86_32_NON_STANDARD
479 bool "Support non-standard 32-bit SMP architectures"
480 depends on X86_32 && SMP
481 depends on X86_EXTENDED_PLATFORM
483 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
484 STA2X11, default subarchitectures. It is intended for a generic
485 binary kernel. If you select them all, kernel will probe it
486 one by one and will fallback to default.
488 # Alphabetically sorted list of Non standard 32 bit platforms
491 bool "NUMAQ (IBM/Sequent)"
492 depends on X86_32_NON_STANDARD
497 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
498 NUMA multiquad box. This changes the way that processors are
499 bootstrapped, and uses Clustered Logical APIC addressing mode instead
500 of Flat Logical. You will need a new lynxer.elf file to flash your
501 firmware with - send email to <Martin.Bligh@us.ibm.com>.
503 config X86_SUPPORTS_MEMORY_FAILURE
505 # MCE code calls memory_failure():
507 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
508 depends on !X86_NUMAQ
509 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
510 depends on X86_64 || !SPARSEMEM
511 select ARCH_SUPPORTS_MEMORY_FAILURE
514 bool "SGI 320/540 (Visual Workstation)"
515 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
516 depends on X86_32_NON_STANDARD
518 The SGI Visual Workstation series is an IA32-based workstation
519 based on SGI systems chips with some legacy PC hardware attached.
521 Say Y here to create a kernel to run on the SGI 320 or 540.
523 A kernel compiled for the Visual Workstation will run on general
524 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
527 bool "STA2X11 Companion Chip Support"
528 depends on X86_32_NON_STANDARD && PCI
529 select X86_DEV_DMA_OPS
533 select ARCH_REQUIRE_GPIOLIB
536 This adds support for boards based on the STA2X11 IO-Hub,
537 a.k.a. "ConneXt". The chip is used in place of the standard
538 PC chipset, so all "standard" peripherals are missing. If this
539 option is selected the kernel will still be able to boot on
540 standard PC machines.
543 bool "Summit/EXA (IBM x440)"
544 depends on X86_32_NON_STANDARD
546 This option is needed for IBM systems that use the Summit/EXA chipset.
547 In particular, it is needed for the x440.
550 bool "Unisys ES7000 IA32 series"
551 depends on X86_32_NON_STANDARD && X86_BIGSMP
553 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
554 supposed to run on an IA32-based Unisys ES7000 system.
557 tristate "Eurobraille/Iris poweroff module"
560 The Iris machines from EuroBraille do not have APM or ACPI support
561 to shut themselves down properly. A special I/O sequence is
562 needed to do so, which is what this module does at
565 This is only for Iris machines from EuroBraille.
569 config SCHED_OMIT_FRAME_POINTER
571 prompt "Single-depth WCHAN output"
574 Calculate simpler /proc/<PID>/wchan values. If this option
575 is disabled then wchan values will recurse back to the
576 caller function. This provides more accurate wchan values,
577 at the expense of slightly more scheduling overhead.
579 If in doubt, say "Y".
581 menuconfig PARAVIRT_GUEST
582 bool "Paravirtualized guest support"
584 Say Y here to get to see options related to running Linux under
585 various hypervisors. This option alone does not add any kernel code.
587 If you say N, all options in this submenu will be skipped and disabled.
591 config PARAVIRT_TIME_ACCOUNTING
592 bool "Paravirtual steal time accounting"
596 Select this option to enable fine granularity task steal time
597 accounting. Time spent executing other tasks in parallel with
598 the current vCPU is discounted from the vCPU power. To account for
599 that, there can be a small performance impact.
601 If in doubt, say N here.
603 source "arch/x86/xen/Kconfig"
606 bool "KVM Guest support (including kvmclock)"
609 select PARAVIRT_CLOCK
610 default y if PARAVIRT_GUEST
612 This option enables various optimizations for running under the KVM
613 hypervisor. It includes a paravirtualized clock, so that instead
614 of relying on a PIT (or probably other) emulation by the
615 underlying device model, the host provides the guest with
616 timing infrastructure such as time of day, and system time
618 source "arch/x86/lguest/Kconfig"
621 bool "Enable paravirtualization code"
623 This changes the kernel so it can modify itself when it is run
624 under a hypervisor, potentially improving performance significantly
625 over full virtualization. However, when run without a hypervisor
626 the kernel is theoretically slower and slightly larger.
628 config PARAVIRT_SPINLOCKS
629 bool "Paravirtualization layer for spinlocks"
630 depends on PARAVIRT && SMP && EXPERIMENTAL
632 Paravirtualized spinlocks allow a pvops backend to replace the
633 spinlock implementation with something virtualization-friendly
634 (for example, block the virtual CPU rather than spinning).
636 Unfortunately the downside is an up to 5% performance hit on
637 native kernels, with various workloads.
639 If you are unsure how to answer this question, answer N.
641 config PARAVIRT_CLOCK
646 config PARAVIRT_DEBUG
647 bool "paravirt-ops debugging"
648 depends on PARAVIRT && DEBUG_KERNEL
650 Enable to debug paravirt_ops internals. Specifically, BUG if
651 a paravirt_op is missing when it is called.
659 This option adds a kernel parameter 'memtest', which allows memtest
661 memtest=0, mean disabled; -- default
662 memtest=1, mean do 1 test pattern;
664 memtest=4, mean do 4 test patterns.
665 If you are unsure how to answer this question, answer N.
667 config X86_SUMMIT_NUMA
669 depends on X86_32 && NUMA && X86_32_NON_STANDARD
671 config X86_CYCLONE_TIMER
673 depends on X86_SUMMIT
675 source "arch/x86/Kconfig.cpu"
679 prompt "HPET Timer Support" if X86_32
681 Use the IA-PC HPET (High Precision Event Timer) to manage
682 time in preference to the PIT and RTC, if a HPET is
684 HPET is the next generation timer replacing legacy 8254s.
685 The HPET 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. You can find the HPET spec at
688 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
690 You can safely choose Y here. However, HPET will only be
691 activated if the platform and the BIOS support this feature.
692 Otherwise the 8254 will be used for timing services.
694 Choose N to continue using the legacy 8254 timer.
696 config HPET_EMULATE_RTC
698 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
701 def_bool y if X86_INTEL_MID
702 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
704 depends on X86_INTEL_MID && SFI
706 APB timer is the replacement for 8254, HPET on X86 MID platforms.
707 The APBT provides a stable time base on SMP
708 systems, unlike the TSC, but it is more expensive to access,
709 as it is off-chip. APB timers are always running regardless of CPU
710 C states, they are used as per CPU clockevent device when possible.
712 # Mark as expert because too many people got it wrong.
713 # The code disables itself when not needed.
716 bool "Enable DMI scanning" if EXPERT
718 Enabled scanning of DMI to identify machine quirks. Say Y
719 here unless you have verified that your setup is not
720 affected by entries in the DMI blacklist. Required by PNP
724 bool "GART IOMMU support" if EXPERT
727 depends on X86_64 && PCI && AMD_NB
729 Support for full DMA access of devices with 32bit memory access only
730 on systems with more than 3GB. This is usually needed for USB,
731 sound, many IDE/SATA chipsets and some other devices.
732 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
733 based hardware IOMMU and a software bounce buffer based IOMMU used
734 on Intel systems and as fallback.
735 The code is only active when needed (enough memory and limited
736 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
740 bool "IBM Calgary IOMMU support"
742 depends on X86_64 && PCI && EXPERIMENTAL
744 Support for hardware IOMMUs in IBM's xSeries x366 and x460
745 systems. Needed to run systems with more than 3GB of memory
746 properly with 32-bit PCI devices that do not support DAC
747 (Double Address Cycle). Calgary also supports bus level
748 isolation, where all DMAs pass through the IOMMU. This
749 prevents them from going anywhere except their intended
750 destination. This catches hard-to-find kernel bugs and
751 mis-behaving drivers and devices that do not use the DMA-API
752 properly to set up their DMA buffers. The IOMMU can be
753 turned off at boot time with the iommu=off parameter.
754 Normally the kernel will make the right choice by itself.
757 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
759 prompt "Should Calgary be enabled by default?"
760 depends on CALGARY_IOMMU
762 Should Calgary be enabled by default? if you choose 'y', Calgary
763 will be used (if it exists). If you choose 'n', Calgary will not be
764 used even if it exists. If you choose 'n' and would like to use
765 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
768 # need this always selected by IOMMU for the VIA workaround
772 Support for software bounce buffers used on x86-64 systems
773 which don't have a hardware IOMMU. Using this PCI devices
774 which can only access 32-bits of memory can be used on systems
775 with more than 3 GB of memory.
780 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
783 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
784 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
785 select CPUMASK_OFFSTACK
787 Enable maximum number of CPUS and NUMA Nodes for this architecture.
791 int "Maximum number of CPUs" if SMP && !MAXSMP
792 range 2 8 if SMP && X86_32 && !X86_BIGSMP
793 range 2 512 if SMP && !MAXSMP
795 default "4096" if MAXSMP
796 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
799 This allows you to specify the maximum number of CPUs which this
800 kernel will support. The maximum supported value is 512 and the
801 minimum value which makes sense is 2.
803 This is purely to save memory - each supported CPU adds
804 approximately eight kilobytes to the kernel image.
807 bool "SMT (Hyperthreading) scheduler support"
810 SMT scheduler support improves the CPU scheduler's decision making
811 when dealing with Intel Pentium 4 chips with HyperThreading at a
812 cost of slightly increased overhead in some places. If unsure say
817 prompt "Multi-core scheduler support"
820 Multi-core scheduler support improves the CPU scheduler's decision
821 making when dealing with multi-core CPU chips at a cost of slightly
822 increased overhead in some places. If unsure say N here.
824 source "kernel/Kconfig.preempt"
827 bool "Local APIC support on uniprocessors"
828 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
830 A local APIC (Advanced Programmable Interrupt Controller) is an
831 integrated interrupt controller in the CPU. If you have a single-CPU
832 system which has a processor with a local APIC, you can say Y here to
833 enable and use it. If you say Y here even though your machine doesn't
834 have a local APIC, then the kernel will still run with no slowdown at
835 all. The local APIC supports CPU-generated self-interrupts (timer,
836 performance counters), and the NMI watchdog which detects hard
840 bool "IO-APIC support on uniprocessors"
841 depends on X86_UP_APIC
843 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
844 SMP-capable replacement for PC-style interrupt controllers. Most
845 SMP systems and many recent uniprocessor systems have one.
847 If you have a single-CPU system with an IO-APIC, you can say Y here
848 to use it. If you say Y here even though your machine doesn't have
849 an IO-APIC, then the kernel will still run with no slowdown at all.
851 config X86_LOCAL_APIC
853 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
857 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
859 config X86_VISWS_APIC
861 depends on X86_32 && X86_VISWS
863 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
864 bool "Reroute for broken boot IRQs"
865 depends on X86_IO_APIC
867 This option enables a workaround that fixes a source of
868 spurious interrupts. This is recommended when threaded
869 interrupt handling is used on systems where the generation of
870 superfluous "boot interrupts" cannot be disabled.
872 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
873 entry in the chipset's IO-APIC is masked (as, e.g. the RT
874 kernel does during interrupt handling). On chipsets where this
875 boot IRQ generation cannot be disabled, this workaround keeps
876 the original IRQ line masked so that only the equivalent "boot
877 IRQ" is delivered to the CPUs. The workaround also tells the
878 kernel to set up the IRQ handler on the boot IRQ line. In this
879 way only one interrupt is delivered to the kernel. Otherwise
880 the spurious second interrupt may cause the kernel to bring
881 down (vital) interrupt lines.
883 Only affects "broken" chipsets. Interrupt sharing may be
884 increased on these systems.
887 bool "Machine Check / overheating reporting"
890 Machine Check support allows the processor to notify the
891 kernel if it detects a problem (e.g. overheating, data corruption).
892 The action the kernel takes depends on the severity of the problem,
893 ranging from warning messages to halting the machine.
897 prompt "Intel MCE features"
898 depends on X86_MCE && X86_LOCAL_APIC
900 Additional support for intel specific MCE features such as
905 prompt "AMD MCE features"
906 depends on X86_MCE && X86_LOCAL_APIC
908 Additional support for AMD specific MCE features such as
909 the DRAM Error Threshold.
911 config X86_ANCIENT_MCE
912 bool "Support for old Pentium 5 / WinChip machine checks"
913 depends on X86_32 && X86_MCE
915 Include support for machine check handling on old Pentium 5 or WinChip
916 systems. These typically need to be enabled explicitely on the command
919 config X86_MCE_THRESHOLD
920 depends on X86_MCE_AMD || X86_MCE_INTEL
923 config X86_MCE_INJECT
925 tristate "Machine check injector support"
927 Provide support for injecting machine checks for testing purposes.
928 If you don't know what a machine check is and you don't do kernel
929 QA it is safe to say n.
931 config X86_THERMAL_VECTOR
933 depends on X86_MCE_INTEL
936 bool "Enable VM86 support" if EXPERT
940 This option is required by programs like DOSEMU to run 16-bit legacy
941 code on X86 processors. It also may be needed by software like
942 XFree86 to initialize some video cards via BIOS. Disabling this
943 option saves about 6k.
946 tristate "Toshiba Laptop support"
949 This adds a driver to safely access the System Management Mode of
950 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
951 not work on models with a Phoenix BIOS. The System Management Mode
952 is used to set the BIOS and power saving options on Toshiba portables.
954 For information on utilities to make use of this driver see the
955 Toshiba Linux utilities web site at:
956 <http://www.buzzard.org.uk/toshiba/>.
958 Say Y if you intend to run this kernel on a Toshiba portable.
962 tristate "Dell laptop support"
965 This adds a driver to safely access the System Management Mode
966 of the CPU on the Dell Inspiron 8000. The System Management Mode
967 is used to read cpu temperature and cooling fan status and to
968 control the fans on the I8K portables.
970 This driver has been tested only on the Inspiron 8000 but it may
971 also work with other Dell laptops. You can force loading on other
972 models by passing the parameter `force=1' to the module. Use at
975 For information on utilities to make use of this driver see the
976 I8K Linux utilities web site at:
977 <http://people.debian.org/~dz/i8k/>
979 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
982 config X86_REBOOTFIXUPS
983 bool "Enable X86 board specific fixups for reboot"
986 This enables chipset and/or board specific fixups to be done
987 in order to get reboot to work correctly. This is only needed on
988 some combinations of hardware and BIOS. The symptom, for which
989 this config is intended, is when reboot ends with a stalled/hung
992 Currently, the only fixup is for the Geode machines using
993 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
995 Say Y if you want to enable the fixup. Currently, it's safe to
996 enable this option even if you don't need it.
1000 tristate "CPU microcode loading support"
1004 If you say Y here, you will be able to update the microcode on
1005 certain Intel and AMD processors. The Intel support is for the
1006 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1007 Xeon etc. The AMD support is for families 0x10 and later. You will
1008 obviously need the actual microcode binary data itself which is not
1009 shipped with the Linux kernel.
1011 This option selects the general module only, you need to select
1012 at least one vendor specific module as well.
1014 To compile this driver as a module, choose M here: the module
1015 will be called microcode.
1017 config MICROCODE_INTEL
1018 bool "Intel microcode loading support"
1019 depends on MICROCODE
1023 This options enables microcode patch loading support for Intel
1026 For latest news and information on obtaining all the required
1027 Intel ingredients for this driver, check:
1028 <http://www.urbanmyth.org/microcode/>.
1030 config MICROCODE_AMD
1031 bool "AMD microcode loading support"
1032 depends on MICROCODE
1035 If you select this option, microcode patch loading support for AMD
1036 processors will be enabled.
1038 config MICROCODE_OLD_INTERFACE
1040 depends on MICROCODE
1043 tristate "/dev/cpu/*/msr - Model-specific register support"
1045 This device gives privileged processes access to the x86
1046 Model-Specific Registers (MSRs). It is a character device with
1047 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1048 MSR accesses are directed to a specific CPU on multi-processor
1052 tristate "/dev/cpu/*/cpuid - CPU information support"
1054 This device gives processes access to the x86 CPUID instruction to
1055 be executed on a specific processor. It is a character device
1056 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1060 prompt "High Memory Support"
1061 default HIGHMEM64G if X86_NUMAQ
1067 depends on !X86_NUMAQ
1069 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1070 However, the address space of 32-bit x86 processors is only 4
1071 Gigabytes large. That means that, if you have a large amount of
1072 physical memory, not all of it can be "permanently mapped" by the
1073 kernel. The physical memory that's not permanently mapped is called
1076 If you are compiling a kernel which will never run on a machine with
1077 more than 1 Gigabyte total physical RAM, answer "off" here (default
1078 choice and suitable for most users). This will result in a "3GB/1GB"
1079 split: 3GB are mapped so that each process sees a 3GB virtual memory
1080 space and the remaining part of the 4GB virtual memory space is used
1081 by the kernel to permanently map as much physical memory as
1084 If the machine has between 1 and 4 Gigabytes physical RAM, then
1087 If more than 4 Gigabytes is used then answer "64GB" here. This
1088 selection turns Intel PAE (Physical Address Extension) mode on.
1089 PAE implements 3-level paging on IA32 processors. PAE is fully
1090 supported by Linux, PAE mode is implemented on all recent Intel
1091 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1092 then the kernel will not boot on CPUs that don't support PAE!
1094 The actual amount of total physical memory will either be
1095 auto detected or can be forced by using a kernel command line option
1096 such as "mem=256M". (Try "man bootparam" or see the documentation of
1097 your boot loader (lilo or loadlin) about how to pass options to the
1098 kernel at boot time.)
1100 If unsure, say "off".
1104 depends on !X86_NUMAQ
1106 Select this if you have a 32-bit processor and between 1 and 4
1107 gigabytes of physical RAM.
1114 Select this if you have a 32-bit processor and more than 4
1115 gigabytes of physical RAM.
1120 depends on EXPERIMENTAL
1121 prompt "Memory split" if EXPERT
1125 Select the desired split between kernel and user memory.
1127 If the address range available to the kernel is less than the
1128 physical memory installed, the remaining memory will be available
1129 as "high memory". Accessing high memory is a little more costly
1130 than low memory, as it needs to be mapped into the kernel first.
1131 Note that increasing the kernel address space limits the range
1132 available to user programs, making the address space there
1133 tighter. Selecting anything other than the default 3G/1G split
1134 will also likely make your kernel incompatible with binary-only
1137 If you are not absolutely sure what you are doing, leave this
1141 bool "3G/1G user/kernel split"
1142 config VMSPLIT_3G_OPT
1144 bool "3G/1G user/kernel split (for full 1G low memory)"
1146 bool "2G/2G user/kernel split"
1147 config VMSPLIT_2G_OPT
1149 bool "2G/2G user/kernel split (for full 2G low memory)"
1151 bool "1G/3G user/kernel split"
1156 default 0xB0000000 if VMSPLIT_3G_OPT
1157 default 0x80000000 if VMSPLIT_2G
1158 default 0x78000000 if VMSPLIT_2G_OPT
1159 default 0x40000000 if VMSPLIT_1G
1165 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1168 bool "PAE (Physical Address Extension) Support"
1169 depends on X86_32 && !HIGHMEM4G
1171 PAE is required for NX support, and furthermore enables
1172 larger swapspace support for non-overcommit purposes. It
1173 has the cost of more pagetable lookup overhead, and also
1174 consumes more pagetable space per process.
1176 config ARCH_PHYS_ADDR_T_64BIT
1178 depends on X86_64 || X86_PAE
1180 config ARCH_DMA_ADDR_T_64BIT
1182 depends on X86_64 || HIGHMEM64G
1184 config DIRECT_GBPAGES
1185 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1189 Allow the kernel linear mapping to use 1GB pages on CPUs that
1190 support it. This can improve the kernel's performance a tiny bit by
1191 reducing TLB pressure. If in doubt, say "Y".
1193 # Common NUMA Features
1195 bool "Numa Memory Allocation and Scheduler Support"
1197 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1198 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1200 Enable NUMA (Non Uniform Memory Access) support.
1202 The kernel will try to allocate memory used by a CPU on the
1203 local memory controller of the CPU and add some more
1204 NUMA awareness to the kernel.
1206 For 64-bit this is recommended if the system is Intel Core i7
1207 (or later), AMD Opteron, or EM64T NUMA.
1209 For 32-bit this is only needed on (rare) 32-bit-only platforms
1210 that support NUMA topologies, such as NUMAQ / Summit, or if you
1211 boot a 32-bit kernel on a 64-bit NUMA platform.
1213 Otherwise, you should say N.
1215 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1216 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1220 prompt "Old style AMD Opteron NUMA detection"
1221 depends on X86_64 && NUMA && PCI
1223 Enable AMD NUMA node topology detection. You should say Y here if
1224 you have a multi processor AMD system. This uses an old method to
1225 read the NUMA configuration directly from the builtin Northbridge
1226 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1227 which also takes priority if both are compiled in.
1229 config X86_64_ACPI_NUMA
1231 prompt "ACPI NUMA detection"
1232 depends on X86_64 && NUMA && ACPI && PCI
1235 Enable ACPI SRAT based node topology detection.
1237 # Some NUMA nodes have memory ranges that span
1238 # other nodes. Even though a pfn is valid and
1239 # between a node's start and end pfns, it may not
1240 # reside on that node. See memmap_init_zone()
1242 config NODES_SPAN_OTHER_NODES
1244 depends on X86_64_ACPI_NUMA
1247 bool "NUMA emulation"
1250 Enable NUMA emulation. A flat machine will be split
1251 into virtual nodes when booted with "numa=fake=N", where N is the
1252 number of nodes. This is only useful for debugging.
1255 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1257 default "10" if MAXSMP
1258 default "6" if X86_64
1259 default "4" if X86_NUMAQ
1261 depends on NEED_MULTIPLE_NODES
1263 Specify the maximum number of NUMA Nodes available on the target
1264 system. Increases memory reserved to accommodate various tables.
1266 config HAVE_ARCH_ALLOC_REMAP
1268 depends on X86_32 && NUMA
1270 config ARCH_HAVE_MEMORY_PRESENT
1272 depends on X86_32 && DISCONTIGMEM
1274 config NEED_NODE_MEMMAP_SIZE
1276 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1278 config ARCH_FLATMEM_ENABLE
1280 depends on X86_32 && !NUMA
1282 config ARCH_DISCONTIGMEM_ENABLE
1284 depends on NUMA && X86_32
1286 config ARCH_DISCONTIGMEM_DEFAULT
1288 depends on NUMA && X86_32
1290 config ARCH_SPARSEMEM_ENABLE
1292 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1293 select SPARSEMEM_STATIC if X86_32
1294 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1296 config ARCH_SPARSEMEM_DEFAULT
1300 config ARCH_SELECT_MEMORY_MODEL
1302 depends on ARCH_SPARSEMEM_ENABLE
1304 config ARCH_MEMORY_PROBE
1306 depends on X86_64 && MEMORY_HOTPLUG
1308 config ARCH_PROC_KCORE_TEXT
1310 depends on X86_64 && PROC_KCORE
1312 config ILLEGAL_POINTER_VALUE
1315 default 0xdead000000000000 if X86_64
1320 bool "Allocate 3rd-level pagetables from highmem"
1323 The VM uses one page table entry for each page of physical memory.
1324 For systems with a lot of RAM, this can be wasteful of precious
1325 low memory. Setting this option will put user-space page table
1326 entries in high memory.
1328 config X86_CHECK_BIOS_CORRUPTION
1329 bool "Check for low memory corruption"
1331 Periodically check for memory corruption in low memory, which
1332 is suspected to be caused by BIOS. Even when enabled in the
1333 configuration, it is disabled at runtime. Enable it by
1334 setting "memory_corruption_check=1" on the kernel command
1335 line. By default it scans the low 64k of memory every 60
1336 seconds; see the memory_corruption_check_size and
1337 memory_corruption_check_period parameters in
1338 Documentation/kernel-parameters.txt to adjust this.
1340 When enabled with the default parameters, this option has
1341 almost no overhead, as it reserves a relatively small amount
1342 of memory and scans it infrequently. It both detects corruption
1343 and prevents it from affecting the running system.
1345 It is, however, intended as a diagnostic tool; if repeatable
1346 BIOS-originated corruption always affects the same memory,
1347 you can use memmap= to prevent the kernel from using that
1350 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1351 bool "Set the default setting of memory_corruption_check"
1352 depends on X86_CHECK_BIOS_CORRUPTION
1355 Set whether the default state of memory_corruption_check is
1358 config X86_RESERVE_LOW
1359 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1363 Specify the amount of low memory to reserve for the BIOS.
1365 The first page contains BIOS data structures that the kernel
1366 must not use, so that page must always be reserved.
1368 By default we reserve the first 64K of physical RAM, as a
1369 number of BIOSes are known to corrupt that memory range
1370 during events such as suspend/resume or monitor cable
1371 insertion, so it must not be used by the kernel.
1373 You can set this to 4 if you are absolutely sure that you
1374 trust the BIOS to get all its memory reservations and usages
1375 right. If you know your BIOS have problems beyond the
1376 default 64K area, you can set this to 640 to avoid using the
1377 entire low memory range.
1379 If you have doubts about the BIOS (e.g. suspend/resume does
1380 not work or there's kernel crashes after certain hardware
1381 hotplug events) then you might want to enable
1382 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1383 typical corruption patterns.
1385 Leave this to the default value of 64 if you are unsure.
1387 config MATH_EMULATION
1389 prompt "Math emulation" if X86_32
1391 Linux can emulate a math coprocessor (used for floating point
1392 operations) if you don't have one. 486DX and Pentium processors have
1393 a math coprocessor built in, 486SX and 386 do not, unless you added
1394 a 487DX or 387, respectively. (The messages during boot time can
1395 give you some hints here ["man dmesg"].) Everyone needs either a
1396 coprocessor or this emulation.
1398 If you don't have a math coprocessor, you need to say Y here; if you
1399 say Y here even though you have a coprocessor, the coprocessor will
1400 be used nevertheless. (This behavior can be changed with the kernel
1401 command line option "no387", which comes handy if your coprocessor
1402 is broken. Try "man bootparam" or see the documentation of your boot
1403 loader (lilo or loadlin) about how to pass options to the kernel at
1404 boot time.) This means that it is a good idea to say Y here if you
1405 intend to use this kernel on different machines.
1407 More information about the internals of the Linux math coprocessor
1408 emulation can be found in <file:arch/x86/math-emu/README>.
1410 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1411 kernel, it won't hurt.
1415 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1417 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1418 the Memory Type Range Registers (MTRRs) may be used to control
1419 processor access to memory ranges. This is most useful if you have
1420 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1421 allows bus write transfers to be combined into a larger transfer
1422 before bursting over the PCI/AGP bus. This can increase performance
1423 of image write operations 2.5 times or more. Saying Y here creates a
1424 /proc/mtrr file which may be used to manipulate your processor's
1425 MTRRs. Typically the X server should use this.
1427 This code has a reasonably generic interface so that similar
1428 control registers on other processors can be easily supported
1431 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1432 Registers (ARRs) which provide a similar functionality to MTRRs. For
1433 these, the ARRs are used to emulate the MTRRs.
1434 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1435 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1436 write-combining. All of these processors are supported by this code
1437 and it makes sense to say Y here if you have one of them.
1439 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1440 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1441 can lead to all sorts of problems, so it's good to say Y here.
1443 You can safely say Y even if your machine doesn't have MTRRs, you'll
1444 just add about 9 KB to your kernel.
1446 See <file:Documentation/x86/mtrr.txt> for more information.
1448 config MTRR_SANITIZER
1450 prompt "MTRR cleanup support"
1453 Convert MTRR layout from continuous to discrete, so X drivers can
1454 add writeback entries.
1456 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1457 The largest mtrr entry size for a continuous block can be set with
1462 config MTRR_SANITIZER_ENABLE_DEFAULT
1463 int "MTRR cleanup enable value (0-1)"
1466 depends on MTRR_SANITIZER
1468 Enable mtrr cleanup default value
1470 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1471 int "MTRR cleanup spare reg num (0-7)"
1474 depends on MTRR_SANITIZER
1476 mtrr cleanup spare entries default, it can be changed via
1477 mtrr_spare_reg_nr=N on the kernel command line.
1481 prompt "x86 PAT support" if EXPERT
1484 Use PAT attributes to setup page level cache control.
1486 PATs are the modern equivalents of MTRRs and are much more
1487 flexible than MTRRs.
1489 Say N here if you see bootup problems (boot crash, boot hang,
1490 spontaneous reboots) or a non-working video driver.
1494 config ARCH_USES_PG_UNCACHED
1500 prompt "x86 architectural random number generator" if EXPERT
1502 Enable the x86 architectural RDRAND instruction
1503 (Intel Bull Mountain technology) to generate random numbers.
1504 If supported, this is a high bandwidth, cryptographically
1505 secure hardware random number generator.
1509 prompt "Supervisor Mode Access Prevention" if EXPERT
1511 Supervisor Mode Access Prevention (SMAP) is a security
1512 feature in newer Intel processors. There is a small
1513 performance cost if this enabled and turned on; there is
1514 also a small increase in the kernel size if this is enabled.
1519 bool "EFI runtime service support"
1522 This enables the kernel to use EFI runtime services that are
1523 available (such as the EFI variable services).
1525 This option is only useful on systems that have EFI firmware.
1526 In addition, you should use the latest ELILO loader available
1527 at <http://elilo.sourceforge.net> in order to take advantage
1528 of EFI runtime services. However, even with this option, the
1529 resultant kernel should continue to boot on existing non-EFI
1533 bool "EFI stub support"
1536 This kernel feature allows a bzImage to be loaded directly
1537 by EFI firmware without the use of a bootloader.
1539 See Documentation/x86/efi-stub.txt for more information.
1543 prompt "Enable seccomp to safely compute untrusted bytecode"
1545 This kernel feature is useful for number crunching applications
1546 that may need to compute untrusted bytecode during their
1547 execution. By using pipes or other transports made available to
1548 the process as file descriptors supporting the read/write
1549 syscalls, it's possible to isolate those applications in
1550 their own address space using seccomp. Once seccomp is
1551 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1552 and the task is only allowed to execute a few safe syscalls
1553 defined by each seccomp mode.
1555 If unsure, say Y. Only embedded should say N here.
1557 config CC_STACKPROTECTOR
1558 bool "Enable -fstack-protector buffer overflow detection"
1560 This option turns on the -fstack-protector GCC feature. This
1561 feature puts, at the beginning of functions, a canary value on
1562 the stack just before the return address, and validates
1563 the value just before actually returning. Stack based buffer
1564 overflows (that need to overwrite this return address) now also
1565 overwrite the canary, which gets detected and the attack is then
1566 neutralized via a kernel panic.
1568 This feature requires gcc version 4.2 or above, or a distribution
1569 gcc with the feature backported. Older versions are automatically
1570 detected and for those versions, this configuration option is
1571 ignored. (and a warning is printed during bootup)
1573 source kernel/Kconfig.hz
1576 bool "kexec system call"
1578 kexec is a system call that implements the ability to shutdown your
1579 current kernel, and to start another kernel. It is like a reboot
1580 but it is independent of the system firmware. And like a reboot
1581 you can start any kernel with it, not just Linux.
1583 The name comes from the similarity to the exec system call.
1585 It is an ongoing process to be certain the hardware in a machine
1586 is properly shutdown, so do not be surprised if this code does not
1587 initially work for you. It may help to enable device hotplugging
1588 support. As of this writing the exact hardware interface is
1589 strongly in flux, so no good recommendation can be made.
1592 bool "kernel crash dumps"
1593 depends on X86_64 || (X86_32 && HIGHMEM)
1595 Generate crash dump after being started by kexec.
1596 This should be normally only set in special crash dump kernels
1597 which are loaded in the main kernel with kexec-tools into
1598 a specially reserved region and then later executed after
1599 a crash by kdump/kexec. The crash dump kernel must be compiled
1600 to a memory address not used by the main kernel or BIOS using
1601 PHYSICAL_START, or it must be built as a relocatable image
1602 (CONFIG_RELOCATABLE=y).
1603 For more details see Documentation/kdump/kdump.txt
1606 bool "kexec jump (EXPERIMENTAL)"
1607 depends on EXPERIMENTAL
1608 depends on KEXEC && HIBERNATION
1610 Jump between original kernel and kexeced kernel and invoke
1611 code in physical address mode via KEXEC
1613 config PHYSICAL_START
1614 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1617 This gives the physical address where the kernel is loaded.
1619 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1620 bzImage will decompress itself to above physical address and
1621 run from there. Otherwise, bzImage will run from the address where
1622 it has been loaded by the boot loader and will ignore above physical
1625 In normal kdump cases one does not have to set/change this option
1626 as now bzImage can be compiled as a completely relocatable image
1627 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1628 address. This option is mainly useful for the folks who don't want
1629 to use a bzImage for capturing the crash dump and want to use a
1630 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1631 to be specifically compiled to run from a specific memory area
1632 (normally a reserved region) and this option comes handy.
1634 So if you are using bzImage for capturing the crash dump,
1635 leave the value here unchanged to 0x1000000 and set
1636 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1637 for capturing the crash dump change this value to start of
1638 the reserved region. In other words, it can be set based on
1639 the "X" value as specified in the "crashkernel=YM@XM"
1640 command line boot parameter passed to the panic-ed
1641 kernel. Please take a look at Documentation/kdump/kdump.txt
1642 for more details about crash dumps.
1644 Usage of bzImage for capturing the crash dump is recommended as
1645 one does not have to build two kernels. Same kernel can be used
1646 as production kernel and capture kernel. Above option should have
1647 gone away after relocatable bzImage support is introduced. But it
1648 is present because there are users out there who continue to use
1649 vmlinux for dump capture. This option should go away down the
1652 Don't change this unless you know what you are doing.
1655 bool "Build a relocatable kernel"
1658 This builds a kernel image that retains relocation information
1659 so it can be loaded someplace besides the default 1MB.
1660 The relocations tend to make the kernel binary about 10% larger,
1661 but are discarded at runtime.
1663 One use is for the kexec on panic case where the recovery kernel
1664 must live at a different physical address than the primary
1667 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1668 it has been loaded at and the compile time physical address
1669 (CONFIG_PHYSICAL_START) is ignored.
1671 # Relocation on x86-32 needs some additional build support
1672 config X86_NEED_RELOCS
1674 depends on X86_32 && RELOCATABLE
1676 config PHYSICAL_ALIGN
1677 hex "Alignment value to which kernel should be aligned" if X86_32
1679 range 0x2000 0x1000000
1681 This value puts the alignment restrictions on physical address
1682 where kernel is loaded and run from. Kernel is compiled for an
1683 address which meets above alignment restriction.
1685 If bootloader loads the kernel at a non-aligned address and
1686 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1687 address aligned to above value and run from there.
1689 If bootloader loads the kernel at a non-aligned address and
1690 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1691 load address and decompress itself to the address it has been
1692 compiled for and run from there. The address for which kernel is
1693 compiled already meets above alignment restrictions. Hence the
1694 end result is that kernel runs from a physical address meeting
1695 above alignment restrictions.
1697 Don't change this unless you know what you are doing.
1700 bool "Support for hot-pluggable CPUs"
1701 depends on SMP && HOTPLUG
1703 Say Y here to allow turning CPUs off and on. CPUs can be
1704 controlled through /sys/devices/system/cpu.
1705 ( Note: power management support will enable this option
1706 automatically on SMP systems. )
1707 Say N if you want to disable CPU hotplug.
1709 config BOOTPARAM_HOTPLUG_CPU0
1710 bool "Set default setting of cpu0_hotpluggable"
1712 depends on HOTPLUG_CPU && EXPERIMENTAL
1714 Set whether default state of cpu0_hotpluggable is on or off.
1716 Say Y here to enable CPU0 hotplug by default. If this switch
1717 is turned on, there is no need to give cpu0_hotplug kernel
1718 parameter and the CPU0 hotplug feature is enabled by default.
1720 Please note: there are two known CPU0 dependencies if you want
1721 to enable the CPU0 hotplug feature either by this switch or by
1722 cpu0_hotplug kernel parameter.
1724 First, resume from hibernate or suspend always starts from CPU0.
1725 So hibernate and suspend are prevented if CPU0 is offline.
1727 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1728 offline if any interrupt can not migrate out of CPU0. There may
1729 be other CPU0 dependencies.
1731 Please make sure the dependencies are under your control before
1732 you enable this feature.
1734 Say N if you don't want to enable CPU0 hotplug feature by default.
1735 You still can enable the CPU0 hotplug feature at boot by kernel
1736 parameter cpu0_hotplug.
1738 config DEBUG_HOTPLUG_CPU0
1740 prompt "Debug CPU0 hotplug"
1741 depends on HOTPLUG_CPU && EXPERIMENTAL
1743 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1744 soon as possible and boots up userspace with CPU0 offlined. User
1745 can online CPU0 back after boot time.
1747 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1748 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1749 compilation or giving cpu0_hotplug kernel parameter at boot.
1755 prompt "Compat VDSO support"
1756 depends on X86_32 || IA32_EMULATION
1758 Map the 32-bit VDSO to the predictable old-style address too.
1760 Say N here if you are running a sufficiently recent glibc
1761 version (2.3.3 or later), to remove the high-mapped
1762 VDSO mapping and to exclusively use the randomized VDSO.
1767 bool "Built-in kernel command line"
1769 Allow for specifying boot arguments to the kernel at
1770 build time. On some systems (e.g. embedded ones), it is
1771 necessary or convenient to provide some or all of the
1772 kernel boot arguments with the kernel itself (that is,
1773 to not rely on the boot loader to provide them.)
1775 To compile command line arguments into the kernel,
1776 set this option to 'Y', then fill in the
1777 the boot arguments in CONFIG_CMDLINE.
1779 Systems with fully functional boot loaders (i.e. non-embedded)
1780 should leave this option set to 'N'.
1783 string "Built-in kernel command string"
1784 depends on CMDLINE_BOOL
1787 Enter arguments here that should be compiled into the kernel
1788 image and used at boot time. If the boot loader provides a
1789 command line at boot time, it is appended to this string to
1790 form the full kernel command line, when the system boots.
1792 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1793 change this behavior.
1795 In most cases, the command line (whether built-in or provided
1796 by the boot loader) should specify the device for the root
1799 config CMDLINE_OVERRIDE
1800 bool "Built-in command line overrides boot loader arguments"
1801 depends on CMDLINE_BOOL
1803 Set this option to 'Y' to have the kernel ignore the boot loader
1804 command line, and use ONLY the built-in command line.
1806 This is used to work around broken boot loaders. This should
1807 be set to 'N' under normal conditions.
1811 config ARCH_ENABLE_MEMORY_HOTPLUG
1813 depends on X86_64 || (X86_32 && HIGHMEM)
1815 config ARCH_ENABLE_MEMORY_HOTREMOVE
1817 depends on MEMORY_HOTPLUG
1819 config USE_PERCPU_NUMA_NODE_ID
1823 menu "Power management and ACPI options"
1825 config ARCH_HIBERNATION_HEADER
1827 depends on X86_64 && HIBERNATION
1829 source "kernel/power/Kconfig"
1831 source "drivers/acpi/Kconfig"
1833 source "drivers/sfi/Kconfig"
1840 tristate "APM (Advanced Power Management) BIOS support"
1841 depends on X86_32 && PM_SLEEP
1843 APM is a BIOS specification for saving power using several different
1844 techniques. This is mostly useful for battery powered laptops with
1845 APM compliant BIOSes. If you say Y here, the system time will be
1846 reset after a RESUME operation, the /proc/apm device will provide
1847 battery status information, and user-space programs will receive
1848 notification of APM "events" (e.g. battery status change).
1850 If you select "Y" here, you can disable actual use of the APM
1851 BIOS by passing the "apm=off" option to the kernel at boot time.
1853 Note that the APM support is almost completely disabled for
1854 machines with more than one CPU.
1856 In order to use APM, you will need supporting software. For location
1857 and more information, read <file:Documentation/power/apm-acpi.txt>
1858 and the Battery Powered Linux mini-HOWTO, available from
1859 <http://www.tldp.org/docs.html#howto>.
1861 This driver does not spin down disk drives (see the hdparm(8)
1862 manpage ("man 8 hdparm") for that), and it doesn't turn off
1863 VESA-compliant "green" monitors.
1865 This driver does not support the TI 4000M TravelMate and the ACER
1866 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1867 desktop machines also don't have compliant BIOSes, and this driver
1868 may cause those machines to panic during the boot phase.
1870 Generally, if you don't have a battery in your machine, there isn't
1871 much point in using this driver and you should say N. If you get
1872 random kernel OOPSes or reboots that don't seem to be related to
1873 anything, try disabling/enabling this option (or disabling/enabling
1876 Some other things you should try when experiencing seemingly random,
1879 1) make sure that you have enough swap space and that it is
1881 2) pass the "no-hlt" option to the kernel
1882 3) switch on floating point emulation in the kernel and pass
1883 the "no387" option to the kernel
1884 4) pass the "floppy=nodma" option to the kernel
1885 5) pass the "mem=4M" option to the kernel (thereby disabling
1886 all but the first 4 MB of RAM)
1887 6) make sure that the CPU is not over clocked.
1888 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1889 8) disable the cache from your BIOS settings
1890 9) install a fan for the video card or exchange video RAM
1891 10) install a better fan for the CPU
1892 11) exchange RAM chips
1893 12) exchange the motherboard.
1895 To compile this driver as a module, choose M here: the
1896 module will be called apm.
1900 config APM_IGNORE_USER_SUSPEND
1901 bool "Ignore USER SUSPEND"
1903 This option will ignore USER SUSPEND requests. On machines with a
1904 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1905 series notebooks, it is necessary to say Y because of a BIOS bug.
1907 config APM_DO_ENABLE
1908 bool "Enable PM at boot time"
1910 Enable APM features at boot time. From page 36 of the APM BIOS
1911 specification: "When disabled, the APM BIOS does not automatically
1912 power manage devices, enter the Standby State, enter the Suspend
1913 State, or take power saving steps in response to CPU Idle calls."
1914 This driver will make CPU Idle calls when Linux is idle (unless this
1915 feature is turned off -- see "Do CPU IDLE calls", below). This
1916 should always save battery power, but more complicated APM features
1917 will be dependent on your BIOS implementation. You may need to turn
1918 this option off if your computer hangs at boot time when using APM
1919 support, or if it beeps continuously instead of suspending. Turn
1920 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1921 T400CDT. This is off by default since most machines do fine without
1926 bool "Make CPU Idle calls when idle"
1928 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1929 On some machines, this can activate improved power savings, such as
1930 a slowed CPU clock rate, when the machine is idle. These idle calls
1931 are made after the idle loop has run for some length of time (e.g.,
1932 333 mS). On some machines, this will cause a hang at boot time or
1933 whenever the CPU becomes idle. (On machines with more than one CPU,
1934 this option does nothing.)
1936 config APM_DISPLAY_BLANK
1937 bool "Enable console blanking using APM"
1939 Enable console blanking using the APM. Some laptops can use this to
1940 turn off the LCD backlight when the screen blanker of the Linux
1941 virtual console blanks the screen. Note that this is only used by
1942 the virtual console screen blanker, and won't turn off the backlight
1943 when using the X Window system. This also doesn't have anything to
1944 do with your VESA-compliant power-saving monitor. Further, this
1945 option doesn't work for all laptops -- it might not turn off your
1946 backlight at all, or it might print a lot of errors to the console,
1947 especially if you are using gpm.
1949 config APM_ALLOW_INTS
1950 bool "Allow interrupts during APM BIOS calls"
1952 Normally we disable external interrupts while we are making calls to
1953 the APM BIOS as a measure to lessen the effects of a badly behaving
1954 BIOS implementation. The BIOS should reenable interrupts if it
1955 needs to. Unfortunately, some BIOSes do not -- especially those in
1956 many of the newer IBM Thinkpads. If you experience hangs when you
1957 suspend, try setting this to Y. Otherwise, say N.
1961 source "drivers/cpufreq/Kconfig"
1963 source "drivers/cpuidle/Kconfig"
1965 source "drivers/idle/Kconfig"
1970 menu "Bus options (PCI etc.)"
1975 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1977 Find out whether you have a PCI motherboard. PCI is the name of a
1978 bus system, i.e. the way the CPU talks to the other stuff inside
1979 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1980 VESA. If you have PCI, say Y, otherwise N.
1983 prompt "PCI access mode"
1984 depends on X86_32 && PCI
1987 On PCI systems, the BIOS can be used to detect the PCI devices and
1988 determine their configuration. However, some old PCI motherboards
1989 have BIOS bugs and may crash if this is done. Also, some embedded
1990 PCI-based systems don't have any BIOS at all. Linux can also try to
1991 detect the PCI hardware directly without using the BIOS.
1993 With this option, you can specify how Linux should detect the
1994 PCI devices. If you choose "BIOS", the BIOS will be used,
1995 if you choose "Direct", the BIOS won't be used, and if you
1996 choose "MMConfig", then PCI Express MMCONFIG will be used.
1997 If you choose "Any", the kernel will try MMCONFIG, then the
1998 direct access method and falls back to the BIOS if that doesn't
1999 work. If unsure, go with the default, which is "Any".
2004 config PCI_GOMMCONFIG
2021 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2023 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2026 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2030 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2034 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2038 depends on PCI && XEN
2046 bool "Support mmconfig PCI config space access"
2047 depends on X86_64 && PCI && ACPI
2049 config PCI_CNB20LE_QUIRK
2050 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2051 depends on PCI && EXPERIMENTAL
2053 Read the PCI windows out of the CNB20LE host bridge. This allows
2054 PCI hotplug to work on systems with the CNB20LE chipset which do
2057 There's no public spec for this chipset, and this functionality
2058 is known to be incomplete.
2060 You should say N unless you know you need this.
2062 source "drivers/pci/pcie/Kconfig"
2064 source "drivers/pci/Kconfig"
2066 # x86_64 have no ISA slots, but can have ISA-style DMA.
2068 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2071 Enables ISA-style DMA support for devices requiring such controllers.
2079 Find out whether you have ISA slots on your motherboard. ISA is the
2080 name of a bus system, i.e. the way the CPU talks to the other stuff
2081 inside your box. Other bus systems are PCI, EISA, MicroChannel
2082 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2083 newer boards don't support it. If you have ISA, say Y, otherwise N.
2089 The Extended Industry Standard Architecture (EISA) bus was
2090 developed as an open alternative to the IBM MicroChannel bus.
2092 The EISA bus provided some of the features of the IBM MicroChannel
2093 bus while maintaining backward compatibility with cards made for
2094 the older ISA bus. The EISA bus saw limited use between 1988 and
2095 1995 when it was made obsolete by the PCI bus.
2097 Say Y here if you are building a kernel for an EISA-based machine.
2101 source "drivers/eisa/Kconfig"
2104 tristate "NatSemi SCx200 support"
2106 This provides basic support for National Semiconductor's
2107 (now AMD's) Geode processors. The driver probes for the
2108 PCI-IDs of several on-chip devices, so its a good dependency
2109 for other scx200_* drivers.
2111 If compiled as a module, the driver is named scx200.
2113 config SCx200HR_TIMER
2114 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2118 This driver provides a clocksource built upon the on-chip
2119 27MHz high-resolution timer. Its also a workaround for
2120 NSC Geode SC-1100's buggy TSC, which loses time when the
2121 processor goes idle (as is done by the scheduler). The
2122 other workaround is idle=poll boot option.
2125 bool "One Laptop Per Child support"
2132 Add support for detecting the unique features of the OLPC
2136 bool "OLPC XO-1 Power Management"
2137 depends on OLPC && MFD_CS5535 && PM_SLEEP
2140 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2143 bool "OLPC XO-1 Real Time Clock"
2144 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2146 Add support for the XO-1 real time clock, which can be used as a
2147 programmable wakeup source.
2150 bool "OLPC XO-1 SCI extras"
2151 depends on OLPC && OLPC_XO1_PM
2157 Add support for SCI-based features of the OLPC XO-1 laptop:
2158 - EC-driven system wakeups
2162 - AC adapter status updates
2163 - Battery status updates
2165 config OLPC_XO15_SCI
2166 bool "OLPC XO-1.5 SCI extras"
2167 depends on OLPC && ACPI
2170 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2171 - EC-driven system wakeups
2172 - AC adapter status updates
2173 - Battery status updates
2176 bool "PCEngines ALIX System Support (LED setup)"
2179 This option enables system support for the PCEngines ALIX.
2180 At present this just sets up LEDs for GPIO control on
2181 ALIX2/3/6 boards. However, other system specific setup should
2184 Note: You must still enable the drivers for GPIO and LED support
2185 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2187 Note: You have to set alix.force=1 for boards with Award BIOS.
2190 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2193 This option enables system support for the Soekris Engineering net5501.
2196 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2200 This option enables system support for the Traverse Technologies GEOS.
2206 depends on CPU_SUP_AMD && PCI
2208 source "drivers/pcmcia/Kconfig"
2210 source "drivers/pci/hotplug/Kconfig"
2213 bool "RapidIO support"
2217 If you say Y here, the kernel will include drivers and
2218 infrastructure code to support RapidIO interconnect devices.
2220 source "drivers/rapidio/Kconfig"
2225 menu "Executable file formats / Emulations"
2227 source "fs/Kconfig.binfmt"
2229 config IA32_EMULATION
2230 bool "IA32 Emulation"
2232 select COMPAT_BINFMT_ELF
2235 Include code to run legacy 32-bit programs under a
2236 64-bit kernel. You should likely turn this on, unless you're
2237 100% sure that you don't have any 32-bit programs left.
2240 tristate "IA32 a.out support"
2241 depends on IA32_EMULATION
2243 Support old a.out binaries in the 32bit emulation.
2246 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2247 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2249 Include code to run binaries for the x32 native 32-bit ABI
2250 for 64-bit processors. An x32 process gets access to the
2251 full 64-bit register file and wide data path while leaving
2252 pointers at 32 bits for smaller memory footprint.
2254 You will need a recent binutils (2.22 or later) with
2255 elf32_x86_64 support enabled to compile a kernel with this
2260 depends on IA32_EMULATION || X86_X32
2261 select ARCH_WANT_OLD_COMPAT_IPC
2264 config COMPAT_FOR_U64_ALIGNMENT
2267 config SYSVIPC_COMPAT
2279 config HAVE_ATOMIC_IOMAP
2283 config HAVE_TEXT_POKE_SMP
2285 select STOP_MACHINE if SMP
2287 config X86_DEV_DMA_OPS
2289 depends on X86_64 || STA2X11
2291 config X86_DMA_REMAP
2295 source "net/Kconfig"
2297 source "drivers/Kconfig"
2299 source "drivers/firmware/Kconfig"
2303 source "arch/x86/Kconfig.debug"
2305 source "security/Kconfig"
2307 source "crypto/Kconfig"
2309 source "arch/x86/kvm/Kconfig"
2311 source "lib/Kconfig"
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blob