3 bool "64-bit kernel" if ARCH = "x86"
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
20 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
21 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
23 select ARCH_CLOCKSOURCE_DATA
24 select ARCH_DISCARD_MEMBLOCK
25 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
26 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
27 select ARCH_HAS_ELF_RANDOMIZE
28 select ARCH_HAS_FAST_MULTIPLIER
29 select ARCH_HAS_GCOV_PROFILE_ALL
30 select ARCH_HAS_PMEM_API if X86_64
31 select ARCH_HAS_MMIO_FLUSH
32 select ARCH_HAS_SG_CHAIN
33 select ARCH_HAVE_NMI_SAFE_CMPXCHG
34 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
35 select ARCH_MIGHT_HAVE_PC_PARPORT
36 select ARCH_MIGHT_HAVE_PC_SERIO
37 select ARCH_SUPPORTS_ATOMIC_RMW
38 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
39 select ARCH_SUPPORTS_INT128 if X86_64
40 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
41 select ARCH_USE_BUILTIN_BSWAP
42 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
43 select ARCH_USE_QUEUED_RWLOCKS
44 select ARCH_USE_QUEUED_SPINLOCKS
45 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
46 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
47 select ARCH_WANT_FRAME_POINTERS
48 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
49 select HAVE_ARCH_MMAP_RND_BITS if MMU
50 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
51 select ARCH_WANT_OPTIONAL_GPIOLIB
52 select BUILDTIME_EXTABLE_SORT
54 select CLKSRC_I8253 if X86_32
55 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
56 select CLOCKSOURCE_WATCHDOG
57 select CLONE_BACKWARDS if X86_32
58 select COMPAT_OLD_SIGACTION if IA32_EMULATION
59 select DCACHE_WORD_ACCESS
60 select EDAC_ATOMIC_SCRUB
62 select GENERIC_CLOCKEVENTS
63 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
64 select GENERIC_CLOCKEVENTS_MIN_ADJUST
65 select GENERIC_CMOS_UPDATE
66 select GENERIC_CPU_AUTOPROBE
67 select GENERIC_EARLY_IOREMAP
68 select GENERIC_FIND_FIRST_BIT
70 select GENERIC_IRQ_PROBE
71 select GENERIC_IRQ_SHOW
72 select GENERIC_PENDING_IRQ if SMP
73 select GENERIC_SMP_IDLE_THREAD
74 select GENERIC_STRNCPY_FROM_USER
75 select GENERIC_STRNLEN_USER
76 select GENERIC_TIME_VSYSCALL
77 select HAVE_ACPI_APEI if ACPI
78 select HAVE_ACPI_APEI_NMI if ACPI
79 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
80 select HAVE_AOUT if X86_32
81 select HAVE_ARCH_AUDITSYSCALL
82 select HAVE_ARCH_HARDENED_USERCOPY
83 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
84 select HAVE_ARCH_JUMP_LABEL
85 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
87 select HAVE_ARCH_KMEMCHECK
88 select HAVE_ARCH_SECCOMP_FILTER
89 select HAVE_ARCH_SOFT_DIRTY if X86_64
90 select HAVE_ARCH_TRACEHOOK
91 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
92 select HAVE_ARCH_WITHIN_STACK_FRAMES
93 select HAVE_CC_STACKPROTECTOR
94 select HAVE_CMPXCHG_DOUBLE
95 select HAVE_CMPXCHG_LOCAL
96 select HAVE_CONTEXT_TRACKING if X86_64
97 select HAVE_COPY_THREAD_TLS
98 select HAVE_C_RECORDMCOUNT
99 select HAVE_DEBUG_KMEMLEAK
100 select HAVE_DEBUG_STACKOVERFLOW
101 select HAVE_DMA_API_DEBUG
102 select HAVE_DMA_ATTRS
103 select HAVE_DMA_CONTIGUOUS
104 select HAVE_DYNAMIC_FTRACE
105 select HAVE_DYNAMIC_FTRACE_WITH_REGS
106 select HAVE_EFFICIENT_UNALIGNED_ACCESS
107 select HAVE_FENTRY if X86_64
108 select HAVE_FTRACE_MCOUNT_RECORD
109 select HAVE_FUNCTION_GRAPH_FP_TEST
110 select HAVE_FUNCTION_GRAPH_TRACER
111 select HAVE_FUNCTION_TRACER
112 select HAVE_GENERIC_DMA_COHERENT if X86_32
113 select HAVE_HW_BREAKPOINT
115 select HAVE_IOREMAP_PROT
116 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
117 select HAVE_IRQ_TIME_ACCOUNTING
118 select HAVE_KERNEL_BZIP2
119 select HAVE_KERNEL_GZIP
120 select HAVE_KERNEL_LZ4
121 select HAVE_KERNEL_LZMA
122 select HAVE_KERNEL_LZO
123 select HAVE_KERNEL_XZ
125 select HAVE_KPROBES_ON_FTRACE
126 select HAVE_KRETPROBES
128 select HAVE_LIVEPATCH if X86_64
130 select HAVE_MEMBLOCK_NODE_MAP
131 select HAVE_MIXED_BREAKPOINTS_REGS
133 select HAVE_OPTPROBES
134 select HAVE_PCSPKR_PLATFORM
135 select HAVE_PERF_EVENTS
136 select HAVE_PERF_EVENTS_NMI
137 select HAVE_PERF_REGS
138 select HAVE_PERF_USER_STACK_DUMP
139 select HAVE_REGS_AND_STACK_ACCESS_API
140 select HAVE_SYSCALL_TRACEPOINTS
141 select HAVE_UID16 if X86_32 || IA32_EMULATION
142 select HAVE_UNSTABLE_SCHED_CLOCK
143 select HAVE_USER_RETURN_NOTIFIER
144 select IRQ_FORCED_THREADING
145 select MODULES_USE_ELF_RELA if X86_64
146 select MODULES_USE_ELF_REL if X86_32
147 select OLD_SIGACTION if X86_32
148 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
153 select SYSCTL_EXCEPTION_TRACE
154 select USER_STACKTRACE_SUPPORT
156 select X86_DEV_DMA_OPS if X86_64
157 select X86_FEATURE_NAMES if PROC_FS
159 config INSTRUCTION_DECODER
161 depends on KPROBES || PERF_EVENTS || UPROBES
163 config PERF_EVENTS_INTEL_UNCORE
165 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
169 default "elf32-i386" if X86_32
170 default "elf64-x86-64" if X86_64
172 config ARCH_DEFCONFIG
174 default "arch/x86/configs/i386_defconfig" if X86_32
175 default "arch/x86/configs/x86_64_defconfig" if X86_64
177 config LOCKDEP_SUPPORT
180 config STACKTRACE_SUPPORT
183 config HAVE_LATENCYTOP_SUPPORT
189 config ARCH_MMAP_RND_BITS_MIN
193 config ARCH_MMAP_RND_BITS_MAX
197 config ARCH_MMAP_RND_COMPAT_BITS_MIN
200 config ARCH_MMAP_RND_COMPAT_BITS_MAX
206 config NEED_DMA_MAP_STATE
208 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
210 config NEED_SG_DMA_LENGTH
213 config GENERIC_ISA_DMA
215 depends on ISA_DMA_API
220 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
222 config GENERIC_BUG_RELATIVE_POINTERS
225 config GENERIC_HWEIGHT
228 config ARCH_MAY_HAVE_PC_FDC
230 depends on ISA_DMA_API
232 config RWSEM_XCHGADD_ALGORITHM
235 config GENERIC_CALIBRATE_DELAY
238 config ARCH_HAS_CPU_RELAX
241 config ARCH_HAS_CACHE_LINE_SIZE
244 config HAVE_SETUP_PER_CPU_AREA
247 config NEED_PER_CPU_EMBED_FIRST_CHUNK
250 config NEED_PER_CPU_PAGE_FIRST_CHUNK
253 config ARCH_HIBERNATION_POSSIBLE
256 config ARCH_SUSPEND_POSSIBLE
259 config ARCH_WANT_HUGE_PMD_SHARE
262 config ARCH_WANT_GENERAL_HUGETLB
271 config ARCH_SUPPORTS_OPTIMIZED_INLINING
274 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
277 config KASAN_SHADOW_OFFSET
280 default 0xdffffc0000000000
282 config HAVE_INTEL_TXT
284 depends on INTEL_IOMMU && ACPI
288 depends on X86_32 && SMP
292 depends on X86_64 && SMP
294 config X86_32_LAZY_GS
296 depends on X86_32 && !CC_STACKPROTECTOR
298 config ARCH_HWEIGHT_CFLAGS
300 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
301 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
303 config ARCH_SUPPORTS_UPROBES
306 config FIX_EARLYCON_MEM
312 config PGTABLE_LEVELS
318 source "init/Kconfig"
319 source "kernel/Kconfig.freezer"
321 menu "Processor type and features"
324 bool "DMA memory allocation support" if EXPERT
327 DMA memory allocation support allows devices with less than 32-bit
328 addressing to allocate within the first 16MB of address space.
329 Disable if no such devices will be used.
334 bool "Symmetric multi-processing support"
336 This enables support for systems with more than one CPU. If you have
337 a system with only one CPU, say N. If you have a system with more
340 If you say N here, the kernel will run on uni- and multiprocessor
341 machines, but will use only one CPU of a multiprocessor machine. If
342 you say Y here, the kernel will run on many, but not all,
343 uniprocessor machines. On a uniprocessor machine, the kernel
344 will run faster if you say N here.
346 Note that if you say Y here and choose architecture "586" or
347 "Pentium" under "Processor family", the kernel will not work on 486
348 architectures. Similarly, multiprocessor kernels for the "PPro"
349 architecture may not work on all Pentium based boards.
351 People using multiprocessor machines who say Y here should also say
352 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
353 Management" code will be disabled if you say Y here.
355 See also <file:Documentation/x86/i386/IO-APIC.txt>,
356 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
357 <http://www.tldp.org/docs.html#howto>.
359 If you don't know what to do here, say N.
361 config X86_FEATURE_NAMES
362 bool "Processor feature human-readable names" if EMBEDDED
365 This option compiles in a table of x86 feature bits and corresponding
366 names. This is required to support /proc/cpuinfo and a few kernel
367 messages. You can disable this to save space, at the expense of
368 making those few kernel messages show numeric feature bits instead.
373 bool "Support x2apic"
374 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
376 This enables x2apic support on CPUs that have this feature.
378 This allows 32-bit apic IDs (so it can support very large systems),
379 and accesses the local apic via MSRs not via mmio.
381 If you don't know what to do here, say N.
384 bool "Enable MPS table" if ACPI || SFI
386 depends on X86_LOCAL_APIC
388 For old smp systems that do not have proper acpi support. Newer systems
389 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
392 bool "Support for big SMP systems with more than 8 CPUs"
393 depends on X86_32 && SMP
395 This option is needed for the systems that have more than 8 CPUs
399 depends on X86_GOLDFISH
402 config X86_EXTENDED_PLATFORM
403 bool "Support for extended (non-PC) x86 platforms"
406 If you disable this option then the kernel will only support
407 standard PC platforms. (which covers the vast majority of
410 If you enable this option then you'll be able to select support
411 for the following (non-PC) 32 bit x86 platforms:
412 Goldfish (Android emulator)
415 SGI 320/540 (Visual Workstation)
416 STA2X11-based (e.g. Northville)
417 Moorestown MID devices
419 If you have one of these systems, or if you want to build a
420 generic distribution kernel, say Y here - otherwise say N.
424 config X86_EXTENDED_PLATFORM
425 bool "Support for extended (non-PC) x86 platforms"
428 If you disable this option then the kernel will only support
429 standard PC platforms. (which covers the vast majority of
432 If you enable this option then you'll be able to select support
433 for the following (non-PC) 64 bit x86 platforms:
438 If you have one of these systems, or if you want to build a
439 generic distribution kernel, say Y here - otherwise say N.
441 # This is an alphabetically sorted list of 64 bit extended platforms
442 # Please maintain the alphabetic order if and when there are additions
444 bool "Numascale NumaChip"
446 depends on X86_EXTENDED_PLATFORM
449 depends on X86_X2APIC
450 depends on PCI_MMCONFIG
452 Adds support for Numascale NumaChip large-SMP systems. Needed to
453 enable more than ~168 cores.
454 If you don't have one of these, you should say N here.
458 select HYPERVISOR_GUEST
460 depends on X86_64 && PCI
461 depends on X86_EXTENDED_PLATFORM
464 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
465 supposed to run on these EM64T-based machines. Only choose this option
466 if you have one of these machines.
469 bool "SGI Ultraviolet"
471 depends on X86_EXTENDED_PLATFORM
473 depends on X86_X2APIC
476 This option is needed in order to support SGI Ultraviolet systems.
477 If you don't have one of these, you should say N here.
479 # Following is an alphabetically sorted list of 32 bit extended platforms
480 # Please maintain the alphabetic order if and when there are additions
483 bool "Goldfish (Virtual Platform)"
484 depends on X86_EXTENDED_PLATFORM
486 Enable support for the Goldfish virtual platform used primarily
487 for Android development. Unless you are building for the Android
488 Goldfish emulator say N here.
491 bool "CE4100 TV platform"
493 depends on PCI_GODIRECT
494 depends on X86_IO_APIC
496 depends on X86_EXTENDED_PLATFORM
497 select X86_REBOOTFIXUPS
499 select OF_EARLY_FLATTREE
501 Select for the Intel CE media processor (CE4100) SOC.
502 This option compiles in support for the CE4100 SOC for settop
503 boxes and media devices.
506 bool "Intel MID platform support"
508 depends on X86_EXTENDED_PLATFORM
509 depends on X86_PLATFORM_DEVICES
512 depends on X86_IO_APIC
518 select MFD_INTEL_MSIC
520 Select to build a kernel capable of supporting Intel MID (Mobile
521 Internet Device) platform systems which do not have the PCI legacy
522 interfaces. If you are building for a PC class system say N here.
524 Intel MID platforms are based on an Intel processor and chipset which
525 consume less power than most of the x86 derivatives.
527 config X86_INTEL_QUARK
528 bool "Intel Quark platform support"
530 depends on X86_EXTENDED_PLATFORM
531 depends on X86_PLATFORM_DEVICES
535 depends on X86_IO_APIC
540 Select to include support for Quark X1000 SoC.
541 Say Y here if you have a Quark based system such as the Arduino
542 compatible Intel Galileo.
544 config X86_INTEL_LPSS
545 bool "Intel Low Power Subsystem Support"
550 Select to build support for Intel Low Power Subsystem such as
551 found on Intel Lynxpoint PCH. Selecting this option enables
552 things like clock tree (common clock framework) and pincontrol
553 which are needed by the LPSS peripheral drivers.
555 config X86_AMD_PLATFORM_DEVICE
556 bool "AMD ACPI2Platform devices support"
561 Select to interpret AMD specific ACPI device to platform device
562 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
563 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
564 implemented under PINCTRL subsystem.
567 tristate "Intel SoC IOSF Sideband support for SoC platforms"
570 This option enables sideband register access support for Intel SoC
571 platforms. On these platforms the IOSF sideband is used in lieu of
572 MSR's for some register accesses, mostly but not limited to thermal
573 and power. Drivers may query the availability of this device to
574 determine if they need the sideband in order to work on these
575 platforms. The sideband is available on the following SoC products.
576 This list is not meant to be exclusive.
581 You should say Y if you are running a kernel on one of these SoC's.
583 config IOSF_MBI_DEBUG
584 bool "Enable IOSF sideband access through debugfs"
585 depends on IOSF_MBI && DEBUG_FS
587 Select this option to expose the IOSF sideband access registers (MCR,
588 MDR, MCRX) through debugfs to write and read register information from
589 different units on the SoC. This is most useful for obtaining device
590 state information for debug and analysis. As this is a general access
591 mechanism, users of this option would have specific knowledge of the
592 device they want to access.
594 If you don't require the option or are in doubt, say N.
597 bool "RDC R-321x SoC"
599 depends on X86_EXTENDED_PLATFORM
601 select X86_REBOOTFIXUPS
603 This option is needed for RDC R-321x system-on-chip, also known
605 If you don't have one of these chips, you should say N here.
607 config X86_32_NON_STANDARD
608 bool "Support non-standard 32-bit SMP architectures"
609 depends on X86_32 && SMP
610 depends on X86_EXTENDED_PLATFORM
612 This option compiles in the bigsmp and STA2X11 default
613 subarchitectures. It is intended for a generic binary
614 kernel. If you select them all, kernel will probe it one by
615 one and will fallback to default.
617 # Alphabetically sorted list of Non standard 32 bit platforms
619 config X86_SUPPORTS_MEMORY_FAILURE
621 # MCE code calls memory_failure():
623 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
624 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
625 depends on X86_64 || !SPARSEMEM
626 select ARCH_SUPPORTS_MEMORY_FAILURE
629 bool "STA2X11 Companion Chip Support"
630 depends on X86_32_NON_STANDARD && PCI
631 select X86_DEV_DMA_OPS
635 select ARCH_REQUIRE_GPIOLIB
638 This adds support for boards based on the STA2X11 IO-Hub,
639 a.k.a. "ConneXt". The chip is used in place of the standard
640 PC chipset, so all "standard" peripherals are missing. If this
641 option is selected the kernel will still be able to boot on
642 standard PC machines.
645 tristate "Eurobraille/Iris poweroff module"
648 The Iris machines from EuroBraille do not have APM or ACPI support
649 to shut themselves down properly. A special I/O sequence is
650 needed to do so, which is what this module does at
653 This is only for Iris machines from EuroBraille.
657 config SCHED_OMIT_FRAME_POINTER
659 prompt "Single-depth WCHAN output"
662 Calculate simpler /proc/<PID>/wchan values. If this option
663 is disabled then wchan values will recurse back to the
664 caller function. This provides more accurate wchan values,
665 at the expense of slightly more scheduling overhead.
667 If in doubt, say "Y".
669 menuconfig HYPERVISOR_GUEST
670 bool "Linux guest support"
672 Say Y here to enable options for running Linux under various hyper-
673 visors. This option enables basic hypervisor detection and platform
676 If you say N, all options in this submenu will be skipped and
677 disabled, and Linux guest support won't be built in.
682 bool "Enable paravirtualization code"
684 This changes the kernel so it can modify itself when it is run
685 under a hypervisor, potentially improving performance significantly
686 over full virtualization. However, when run without a hypervisor
687 the kernel is theoretically slower and slightly larger.
689 config PARAVIRT_DEBUG
690 bool "paravirt-ops debugging"
691 depends on PARAVIRT && DEBUG_KERNEL
693 Enable to debug paravirt_ops internals. Specifically, BUG if
694 a paravirt_op is missing when it is called.
696 config PARAVIRT_SPINLOCKS
697 bool "Paravirtualization layer for spinlocks"
698 depends on PARAVIRT && SMP
699 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
701 Paravirtualized spinlocks allow a pvops backend to replace the
702 spinlock implementation with something virtualization-friendly
703 (for example, block the virtual CPU rather than spinning).
705 It has a minimal impact on native kernels and gives a nice performance
706 benefit on paravirtualized KVM / Xen kernels.
708 If you are unsure how to answer this question, answer Y.
710 source "arch/x86/xen/Kconfig"
713 bool "KVM Guest support (including kvmclock)"
715 select PARAVIRT_CLOCK
718 This option enables various optimizations for running under the KVM
719 hypervisor. It includes a paravirtualized clock, so that instead
720 of relying on a PIT (or probably other) emulation by the
721 underlying device model, the host provides the guest with
722 timing infrastructure such as time of day, and system time
725 bool "Enable debug information for KVM Guests in debugfs"
726 depends on KVM_GUEST && DEBUG_FS
729 This option enables collection of various statistics for KVM guest.
730 Statistics are displayed in debugfs filesystem. Enabling this option
731 may incur significant overhead.
733 source "arch/x86/lguest/Kconfig"
735 config PARAVIRT_TIME_ACCOUNTING
736 bool "Paravirtual steal time accounting"
740 Select this option to enable fine granularity task steal time
741 accounting. Time spent executing other tasks in parallel with
742 the current vCPU is discounted from the vCPU power. To account for
743 that, there can be a small performance impact.
745 If in doubt, say N here.
747 config PARAVIRT_CLOCK
750 endif #HYPERVISOR_GUEST
755 source "arch/x86/Kconfig.cpu"
759 prompt "HPET Timer Support" if X86_32
761 Use the IA-PC HPET (High Precision Event Timer) to manage
762 time in preference to the PIT and RTC, if a HPET is
764 HPET is the next generation timer replacing legacy 8254s.
765 The HPET provides a stable time base on SMP
766 systems, unlike the TSC, but it is more expensive to access,
767 as it is off-chip. You can find the HPET spec at
768 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
770 You can safely choose Y here. However, HPET will only be
771 activated if the platform and the BIOS support this feature.
772 Otherwise the 8254 will be used for timing services.
774 Choose N to continue using the legacy 8254 timer.
776 config HPET_EMULATE_RTC
778 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
781 def_bool y if X86_INTEL_MID
782 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
784 depends on X86_INTEL_MID && SFI
786 APB timer is the replacement for 8254, HPET on X86 MID platforms.
787 The APBT provides a stable time base on SMP
788 systems, unlike the TSC, but it is more expensive to access,
789 as it is off-chip. APB timers are always running regardless of CPU
790 C states, they are used as per CPU clockevent device when possible.
792 # Mark as expert because too many people got it wrong.
793 # The code disables itself when not needed.
796 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
797 bool "Enable DMI scanning" if EXPERT
799 Enabled scanning of DMI to identify machine quirks. Say Y
800 here unless you have verified that your setup is not
801 affected by entries in the DMI blacklist. Required by PNP
805 bool "Old AMD GART IOMMU support"
807 depends on X86_64 && PCI && AMD_NB
809 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
810 GART based hardware IOMMUs.
812 The GART supports full DMA access for devices with 32-bit access
813 limitations, on systems with more than 3 GB. This is usually needed
814 for USB, sound, many IDE/SATA chipsets and some other devices.
816 Newer systems typically have a modern AMD IOMMU, supported via
817 the CONFIG_AMD_IOMMU=y config option.
819 In normal configurations this driver is only active when needed:
820 there's more than 3 GB of memory and the system contains a
821 32-bit limited device.
826 bool "IBM Calgary IOMMU support"
828 depends on X86_64 && PCI
830 Support for hardware IOMMUs in IBM's xSeries x366 and x460
831 systems. Needed to run systems with more than 3GB of memory
832 properly with 32-bit PCI devices that do not support DAC
833 (Double Address Cycle). Calgary also supports bus level
834 isolation, where all DMAs pass through the IOMMU. This
835 prevents them from going anywhere except their intended
836 destination. This catches hard-to-find kernel bugs and
837 mis-behaving drivers and devices that do not use the DMA-API
838 properly to set up their DMA buffers. The IOMMU can be
839 turned off at boot time with the iommu=off parameter.
840 Normally the kernel will make the right choice by itself.
843 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
845 prompt "Should Calgary be enabled by default?"
846 depends on CALGARY_IOMMU
848 Should Calgary be enabled by default? if you choose 'y', Calgary
849 will be used (if it exists). If you choose 'n', Calgary will not be
850 used even if it exists. If you choose 'n' and would like to use
851 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
854 # need this always selected by IOMMU for the VIA workaround
858 Support for software bounce buffers used on x86-64 systems
859 which don't have a hardware IOMMU. Using this PCI devices
860 which can only access 32-bits of memory can be used on systems
861 with more than 3 GB of memory.
866 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
869 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
870 depends on X86_64 && SMP && DEBUG_KERNEL
871 select CPUMASK_OFFSTACK
873 Enable maximum number of CPUS and NUMA Nodes for this architecture.
877 int "Maximum number of CPUs" if SMP && !MAXSMP
878 range 2 8 if SMP && X86_32 && !X86_BIGSMP
879 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
880 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
882 default "8192" if MAXSMP
883 default "32" if SMP && X86_BIGSMP
884 default "8" if SMP && X86_32
887 This allows you to specify the maximum number of CPUs which this
888 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
889 supported value is 8192, otherwise the maximum value is 512. The
890 minimum value which makes sense is 2.
892 This is purely to save memory - each supported CPU adds
893 approximately eight kilobytes to the kernel image.
896 bool "SMT (Hyperthreading) scheduler support"
899 SMT scheduler support improves the CPU scheduler's decision making
900 when dealing with Intel Pentium 4 chips with HyperThreading at a
901 cost of slightly increased overhead in some places. If unsure say
906 prompt "Multi-core scheduler support"
909 Multi-core scheduler support improves the CPU scheduler's decision
910 making when dealing with multi-core CPU chips at a cost of slightly
911 increased overhead in some places. If unsure say N here.
913 source "kernel/Kconfig.preempt"
917 depends on !SMP && X86_LOCAL_APIC
920 bool "Local APIC support on uniprocessors" if !PCI_MSI
922 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
924 A local APIC (Advanced Programmable Interrupt Controller) is an
925 integrated interrupt controller in the CPU. If you have a single-CPU
926 system which has a processor with a local APIC, you can say Y here to
927 enable and use it. If you say Y here even though your machine doesn't
928 have a local APIC, then the kernel will still run with no slowdown at
929 all. The local APIC supports CPU-generated self-interrupts (timer,
930 performance counters), and the NMI watchdog which detects hard
934 bool "IO-APIC support on uniprocessors"
935 depends on X86_UP_APIC
937 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
938 SMP-capable replacement for PC-style interrupt controllers. Most
939 SMP systems and many recent uniprocessor systems have one.
941 If you have a single-CPU system with an IO-APIC, you can say Y here
942 to use it. If you say Y here even though your machine doesn't have
943 an IO-APIC, then the kernel will still run with no slowdown at all.
945 config X86_LOCAL_APIC
947 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
948 select IRQ_DOMAIN_HIERARCHY
949 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
953 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
955 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
956 bool "Reroute for broken boot IRQs"
957 depends on X86_IO_APIC
959 This option enables a workaround that fixes a source of
960 spurious interrupts. This is recommended when threaded
961 interrupt handling is used on systems where the generation of
962 superfluous "boot interrupts" cannot be disabled.
964 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
965 entry in the chipset's IO-APIC is masked (as, e.g. the RT
966 kernel does during interrupt handling). On chipsets where this
967 boot IRQ generation cannot be disabled, this workaround keeps
968 the original IRQ line masked so that only the equivalent "boot
969 IRQ" is delivered to the CPUs. The workaround also tells the
970 kernel to set up the IRQ handler on the boot IRQ line. In this
971 way only one interrupt is delivered to the kernel. Otherwise
972 the spurious second interrupt may cause the kernel to bring
973 down (vital) interrupt lines.
975 Only affects "broken" chipsets. Interrupt sharing may be
976 increased on these systems.
979 bool "Machine Check / overheating reporting"
980 select GENERIC_ALLOCATOR
983 Machine Check support allows the processor to notify the
984 kernel if it detects a problem (e.g. overheating, data corruption).
985 The action the kernel takes depends on the severity of the problem,
986 ranging from warning messages to halting the machine.
990 prompt "Intel MCE features"
991 depends on X86_MCE && X86_LOCAL_APIC
993 Additional support for intel specific MCE features such as
998 prompt "AMD MCE features"
999 depends on X86_MCE && X86_LOCAL_APIC
1001 Additional support for AMD specific MCE features such as
1002 the DRAM Error Threshold.
1004 config X86_ANCIENT_MCE
1005 bool "Support for old Pentium 5 / WinChip machine checks"
1006 depends on X86_32 && X86_MCE
1008 Include support for machine check handling on old Pentium 5 or WinChip
1009 systems. These typically need to be enabled explicitly on the command
1012 config X86_MCE_THRESHOLD
1013 depends on X86_MCE_AMD || X86_MCE_INTEL
1016 config X86_MCE_INJECT
1018 tristate "Machine check injector support"
1020 Provide support for injecting machine checks for testing purposes.
1021 If you don't know what a machine check is and you don't do kernel
1022 QA it is safe to say n.
1024 config X86_THERMAL_VECTOR
1026 depends on X86_MCE_INTEL
1028 config X86_LEGACY_VM86
1029 bool "Legacy VM86 support"
1033 This option allows user programs to put the CPU into V8086
1034 mode, which is an 80286-era approximation of 16-bit real mode.
1036 Some very old versions of X and/or vbetool require this option
1037 for user mode setting. Similarly, DOSEMU will use it if
1038 available to accelerate real mode DOS programs. However, any
1039 recent version of DOSEMU, X, or vbetool should be fully
1040 functional even without kernel VM86 support, as they will all
1041 fall back to software emulation. Nevertheless, if you are using
1042 a 16-bit DOS program where 16-bit performance matters, vm86
1043 mode might be faster than emulation and you might want to
1046 Note that any app that works on a 64-bit kernel is unlikely to
1047 need this option, as 64-bit kernels don't, and can't, support
1048 V8086 mode. This option is also unrelated to 16-bit protected
1049 mode and is not needed to run most 16-bit programs under Wine.
1051 Enabling this option increases the complexity of the kernel
1052 and slows down exception handling a tiny bit.
1054 If unsure, say N here.
1058 default X86_LEGACY_VM86
1061 bool "Enable support for 16-bit segments" if EXPERT
1063 depends on MODIFY_LDT_SYSCALL
1065 This option is required by programs like Wine to run 16-bit
1066 protected mode legacy code on x86 processors. Disabling
1067 this option saves about 300 bytes on i386, or around 6K text
1068 plus 16K runtime memory on x86-64,
1072 depends on X86_16BIT && X86_32
1076 depends on X86_16BIT && X86_64
1078 config X86_VSYSCALL_EMULATION
1079 bool "Enable vsyscall emulation" if EXPERT
1083 This enables emulation of the legacy vsyscall page. Disabling
1084 it is roughly equivalent to booting with vsyscall=none, except
1085 that it will also disable the helpful warning if a program
1086 tries to use a vsyscall. With this option set to N, offending
1087 programs will just segfault, citing addresses of the form
1090 This option is required by many programs built before 2013, and
1091 care should be used even with newer programs if set to N.
1093 Disabling this option saves about 7K of kernel size and
1094 possibly 4K of additional runtime pagetable memory.
1097 tristate "Toshiba Laptop support"
1100 This adds a driver to safely access the System Management Mode of
1101 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1102 not work on models with a Phoenix BIOS. The System Management Mode
1103 is used to set the BIOS and power saving options on Toshiba portables.
1105 For information on utilities to make use of this driver see the
1106 Toshiba Linux utilities web site at:
1107 <http://www.buzzard.org.uk/toshiba/>.
1109 Say Y if you intend to run this kernel on a Toshiba portable.
1113 tristate "Dell i8k legacy laptop support"
1115 select SENSORS_DELL_SMM
1117 This option enables legacy /proc/i8k userspace interface in hwmon
1118 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1119 temperature and allows controlling fan speeds of Dell laptops via
1120 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1121 it reports also power and hotkey status. For fan speed control is
1122 needed userspace package i8kutils.
1124 Say Y if you intend to run this kernel on old Dell laptops or want to
1125 use userspace package i8kutils.
1128 config X86_REBOOTFIXUPS
1129 bool "Enable X86 board specific fixups for reboot"
1132 This enables chipset and/or board specific fixups to be done
1133 in order to get reboot to work correctly. This is only needed on
1134 some combinations of hardware and BIOS. The symptom, for which
1135 this config is intended, is when reboot ends with a stalled/hung
1138 Currently, the only fixup is for the Geode machines using
1139 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1141 Say Y if you want to enable the fixup. Currently, it's safe to
1142 enable this option even if you don't need it.
1146 bool "CPU microcode loading support"
1148 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1151 If you say Y here, you will be able to update the microcode on
1152 Intel and AMD processors. The Intel support is for the IA32 family,
1153 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1154 AMD support is for families 0x10 and later. You will obviously need
1155 the actual microcode binary data itself which is not shipped with
1158 The preferred method to load microcode from a detached initrd is described
1159 in Documentation/x86/early-microcode.txt. For that you need to enable
1160 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1161 initrd for microcode blobs.
1163 In addition, you can build-in the microcode into the kernel. For that you
1164 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1165 to the CONFIG_EXTRA_FIRMWARE config option.
1167 config MICROCODE_INTEL
1168 bool "Intel microcode loading support"
1169 depends on MICROCODE
1173 This options enables microcode patch loading support for Intel
1176 For the current Intel microcode data package go to
1177 <https://downloadcenter.intel.com> and search for
1178 'Linux Processor Microcode Data File'.
1180 config MICROCODE_AMD
1181 bool "AMD microcode loading support"
1182 depends on MICROCODE
1185 If you select this option, microcode patch loading support for AMD
1186 processors will be enabled.
1188 config MICROCODE_OLD_INTERFACE
1190 depends on MICROCODE
1193 tristate "/dev/cpu/*/msr - Model-specific register support"
1195 This device gives privileged processes access to the x86
1196 Model-Specific Registers (MSRs). It is a character device with
1197 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1198 MSR accesses are directed to a specific CPU on multi-processor
1202 tristate "/dev/cpu/*/cpuid - CPU information support"
1204 This device gives processes access to the x86 CPUID instruction to
1205 be executed on a specific processor. It is a character device
1206 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1210 prompt "High Memory Support"
1217 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1218 However, the address space of 32-bit x86 processors is only 4
1219 Gigabytes large. That means that, if you have a large amount of
1220 physical memory, not all of it can be "permanently mapped" by the
1221 kernel. The physical memory that's not permanently mapped is called
1224 If you are compiling a kernel which will never run on a machine with
1225 more than 1 Gigabyte total physical RAM, answer "off" here (default
1226 choice and suitable for most users). This will result in a "3GB/1GB"
1227 split: 3GB are mapped so that each process sees a 3GB virtual memory
1228 space and the remaining part of the 4GB virtual memory space is used
1229 by the kernel to permanently map as much physical memory as
1232 If the machine has between 1 and 4 Gigabytes physical RAM, then
1235 If more than 4 Gigabytes is used then answer "64GB" here. This
1236 selection turns Intel PAE (Physical Address Extension) mode on.
1237 PAE implements 3-level paging on IA32 processors. PAE is fully
1238 supported by Linux, PAE mode is implemented on all recent Intel
1239 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1240 then the kernel will not boot on CPUs that don't support PAE!
1242 The actual amount of total physical memory will either be
1243 auto detected or can be forced by using a kernel command line option
1244 such as "mem=256M". (Try "man bootparam" or see the documentation of
1245 your boot loader (lilo or loadlin) about how to pass options to the
1246 kernel at boot time.)
1248 If unsure, say "off".
1253 Select this if you have a 32-bit processor and between 1 and 4
1254 gigabytes of physical RAM.
1261 Select this if you have a 32-bit processor and more than 4
1262 gigabytes of physical RAM.
1267 prompt "Memory split" if EXPERT
1271 Select the desired split between kernel and user memory.
1273 If the address range available to the kernel is less than the
1274 physical memory installed, the remaining memory will be available
1275 as "high memory". Accessing high memory is a little more costly
1276 than low memory, as it needs to be mapped into the kernel first.
1277 Note that increasing the kernel address space limits the range
1278 available to user programs, making the address space there
1279 tighter. Selecting anything other than the default 3G/1G split
1280 will also likely make your kernel incompatible with binary-only
1283 If you are not absolutely sure what you are doing, leave this
1287 bool "3G/1G user/kernel split"
1288 config VMSPLIT_3G_OPT
1290 bool "3G/1G user/kernel split (for full 1G low memory)"
1292 bool "2G/2G user/kernel split"
1293 config VMSPLIT_2G_OPT
1295 bool "2G/2G user/kernel split (for full 2G low memory)"
1297 bool "1G/3G user/kernel split"
1302 default 0xB0000000 if VMSPLIT_3G_OPT
1303 default 0x80000000 if VMSPLIT_2G
1304 default 0x78000000 if VMSPLIT_2G_OPT
1305 default 0x40000000 if VMSPLIT_1G
1311 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1314 bool "PAE (Physical Address Extension) Support"
1315 depends on X86_32 && !HIGHMEM4G
1318 PAE is required for NX support, and furthermore enables
1319 larger swapspace support for non-overcommit purposes. It
1320 has the cost of more pagetable lookup overhead, and also
1321 consumes more pagetable space per process.
1323 config ARCH_PHYS_ADDR_T_64BIT
1325 depends on X86_64 || X86_PAE
1327 config ARCH_DMA_ADDR_T_64BIT
1329 depends on X86_64 || HIGHMEM64G
1331 config X86_DIRECT_GBPAGES
1333 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1335 Certain kernel features effectively disable kernel
1336 linear 1 GB mappings (even if the CPU otherwise
1337 supports them), so don't confuse the user by printing
1338 that we have them enabled.
1340 # Common NUMA Features
1342 bool "Numa Memory Allocation and Scheduler Support"
1344 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1345 default y if X86_BIGSMP
1347 Enable NUMA (Non Uniform Memory Access) support.
1349 The kernel will try to allocate memory used by a CPU on the
1350 local memory controller of the CPU and add some more
1351 NUMA awareness to the kernel.
1353 For 64-bit this is recommended if the system is Intel Core i7
1354 (or later), AMD Opteron, or EM64T NUMA.
1356 For 32-bit this is only needed if you boot a 32-bit
1357 kernel on a 64-bit NUMA platform.
1359 Otherwise, you should say N.
1363 prompt "Old style AMD Opteron NUMA detection"
1364 depends on X86_64 && NUMA && PCI
1366 Enable AMD NUMA node topology detection. You should say Y here if
1367 you have a multi processor AMD system. This uses an old method to
1368 read the NUMA configuration directly from the builtin Northbridge
1369 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1370 which also takes priority if both are compiled in.
1372 config X86_64_ACPI_NUMA
1374 prompt "ACPI NUMA detection"
1375 depends on X86_64 && NUMA && ACPI && PCI
1378 Enable ACPI SRAT based node topology detection.
1380 # Some NUMA nodes have memory ranges that span
1381 # other nodes. Even though a pfn is valid and
1382 # between a node's start and end pfns, it may not
1383 # reside on that node. See memmap_init_zone()
1385 config NODES_SPAN_OTHER_NODES
1387 depends on X86_64_ACPI_NUMA
1390 bool "NUMA emulation"
1393 Enable NUMA emulation. A flat machine will be split
1394 into virtual nodes when booted with "numa=fake=N", where N is the
1395 number of nodes. This is only useful for debugging.
1398 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1400 default "10" if MAXSMP
1401 default "6" if X86_64
1403 depends on NEED_MULTIPLE_NODES
1405 Specify the maximum number of NUMA Nodes available on the target
1406 system. Increases memory reserved to accommodate various tables.
1408 config ARCH_HAVE_MEMORY_PRESENT
1410 depends on X86_32 && DISCONTIGMEM
1412 config NEED_NODE_MEMMAP_SIZE
1414 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1416 config ARCH_FLATMEM_ENABLE
1418 depends on X86_32 && !NUMA
1420 config ARCH_DISCONTIGMEM_ENABLE
1422 depends on NUMA && X86_32
1424 config ARCH_DISCONTIGMEM_DEFAULT
1426 depends on NUMA && X86_32
1428 config ARCH_SPARSEMEM_ENABLE
1430 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1431 select SPARSEMEM_STATIC if X86_32
1432 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1434 config ARCH_SPARSEMEM_DEFAULT
1438 config ARCH_SELECT_MEMORY_MODEL
1440 depends on ARCH_SPARSEMEM_ENABLE
1442 config ARCH_MEMORY_PROBE
1443 bool "Enable sysfs memory/probe interface"
1444 depends on X86_64 && MEMORY_HOTPLUG
1446 This option enables a sysfs memory/probe interface for testing.
1447 See Documentation/memory-hotplug.txt for more information.
1448 If you are unsure how to answer this question, answer N.
1450 config ARCH_PROC_KCORE_TEXT
1452 depends on X86_64 && PROC_KCORE
1454 config ILLEGAL_POINTER_VALUE
1457 default 0xdead000000000000 if X86_64
1461 config X86_PMEM_LEGACY_DEVICE
1464 config X86_PMEM_LEGACY
1465 tristate "Support non-standard NVDIMMs and ADR protected memory"
1466 depends on PHYS_ADDR_T_64BIT
1468 select X86_PMEM_LEGACY_DEVICE
1471 Treat memory marked using the non-standard e820 type of 12 as used
1472 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1473 The kernel will offer these regions to the 'pmem' driver so
1474 they can be used for persistent storage.
1479 bool "Allocate 3rd-level pagetables from highmem"
1482 The VM uses one page table entry for each page of physical memory.
1483 For systems with a lot of RAM, this can be wasteful of precious
1484 low memory. Setting this option will put user-space page table
1485 entries in high memory.
1487 config X86_CHECK_BIOS_CORRUPTION
1488 bool "Check for low memory corruption"
1490 Periodically check for memory corruption in low memory, which
1491 is suspected to be caused by BIOS. Even when enabled in the
1492 configuration, it is disabled at runtime. Enable it by
1493 setting "memory_corruption_check=1" on the kernel command
1494 line. By default it scans the low 64k of memory every 60
1495 seconds; see the memory_corruption_check_size and
1496 memory_corruption_check_period parameters in
1497 Documentation/kernel-parameters.txt to adjust this.
1499 When enabled with the default parameters, this option has
1500 almost no overhead, as it reserves a relatively small amount
1501 of memory and scans it infrequently. It both detects corruption
1502 and prevents it from affecting the running system.
1504 It is, however, intended as a diagnostic tool; if repeatable
1505 BIOS-originated corruption always affects the same memory,
1506 you can use memmap= to prevent the kernel from using that
1509 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1510 bool "Set the default setting of memory_corruption_check"
1511 depends on X86_CHECK_BIOS_CORRUPTION
1514 Set whether the default state of memory_corruption_check is
1517 config X86_RESERVE_LOW
1518 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1522 Specify the amount of low memory to reserve for the BIOS.
1524 The first page contains BIOS data structures that the kernel
1525 must not use, so that page must always be reserved.
1527 By default we reserve the first 64K of physical RAM, as a
1528 number of BIOSes are known to corrupt that memory range
1529 during events such as suspend/resume or monitor cable
1530 insertion, so it must not be used by the kernel.
1532 You can set this to 4 if you are absolutely sure that you
1533 trust the BIOS to get all its memory reservations and usages
1534 right. If you know your BIOS have problems beyond the
1535 default 64K area, you can set this to 640 to avoid using the
1536 entire low memory range.
1538 If you have doubts about the BIOS (e.g. suspend/resume does
1539 not work or there's kernel crashes after certain hardware
1540 hotplug events) then you might want to enable
1541 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1542 typical corruption patterns.
1544 Leave this to the default value of 64 if you are unsure.
1546 config MATH_EMULATION
1548 depends on MODIFY_LDT_SYSCALL
1549 prompt "Math emulation" if X86_32
1551 Linux can emulate a math coprocessor (used for floating point
1552 operations) if you don't have one. 486DX and Pentium processors have
1553 a math coprocessor built in, 486SX and 386 do not, unless you added
1554 a 487DX or 387, respectively. (The messages during boot time can
1555 give you some hints here ["man dmesg"].) Everyone needs either a
1556 coprocessor or this emulation.
1558 If you don't have a math coprocessor, you need to say Y here; if you
1559 say Y here even though you have a coprocessor, the coprocessor will
1560 be used nevertheless. (This behavior can be changed with the kernel
1561 command line option "no387", which comes handy if your coprocessor
1562 is broken. Try "man bootparam" or see the documentation of your boot
1563 loader (lilo or loadlin) about how to pass options to the kernel at
1564 boot time.) This means that it is a good idea to say Y here if you
1565 intend to use this kernel on different machines.
1567 More information about the internals of the Linux math coprocessor
1568 emulation can be found in <file:arch/x86/math-emu/README>.
1570 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1571 kernel, it won't hurt.
1575 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1577 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1578 the Memory Type Range Registers (MTRRs) may be used to control
1579 processor access to memory ranges. This is most useful if you have
1580 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1581 allows bus write transfers to be combined into a larger transfer
1582 before bursting over the PCI/AGP bus. This can increase performance
1583 of image write operations 2.5 times or more. Saying Y here creates a
1584 /proc/mtrr file which may be used to manipulate your processor's
1585 MTRRs. Typically the X server should use this.
1587 This code has a reasonably generic interface so that similar
1588 control registers on other processors can be easily supported
1591 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1592 Registers (ARRs) which provide a similar functionality to MTRRs. For
1593 these, the ARRs are used to emulate the MTRRs.
1594 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1595 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1596 write-combining. All of these processors are supported by this code
1597 and it makes sense to say Y here if you have one of them.
1599 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1600 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1601 can lead to all sorts of problems, so it's good to say Y here.
1603 You can safely say Y even if your machine doesn't have MTRRs, you'll
1604 just add about 9 KB to your kernel.
1606 See <file:Documentation/x86/mtrr.txt> for more information.
1608 config MTRR_SANITIZER
1610 prompt "MTRR cleanup support"
1613 Convert MTRR layout from continuous to discrete, so X drivers can
1614 add writeback entries.
1616 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1617 The largest mtrr entry size for a continuous block can be set with
1622 config MTRR_SANITIZER_ENABLE_DEFAULT
1623 int "MTRR cleanup enable value (0-1)"
1626 depends on MTRR_SANITIZER
1628 Enable mtrr cleanup default value
1630 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1631 int "MTRR cleanup spare reg num (0-7)"
1634 depends on MTRR_SANITIZER
1636 mtrr cleanup spare entries default, it can be changed via
1637 mtrr_spare_reg_nr=N on the kernel command line.
1641 prompt "x86 PAT support" if EXPERT
1644 Use PAT attributes to setup page level cache control.
1646 PATs are the modern equivalents of MTRRs and are much more
1647 flexible than MTRRs.
1649 Say N here if you see bootup problems (boot crash, boot hang,
1650 spontaneous reboots) or a non-working video driver.
1654 config ARCH_USES_PG_UNCACHED
1660 prompt "x86 architectural random number generator" if EXPERT
1662 Enable the x86 architectural RDRAND instruction
1663 (Intel Bull Mountain technology) to generate random numbers.
1664 If supported, this is a high bandwidth, cryptographically
1665 secure hardware random number generator.
1669 prompt "Supervisor Mode Access Prevention" if EXPERT
1671 Supervisor Mode Access Prevention (SMAP) is a security
1672 feature in newer Intel processors. There is a small
1673 performance cost if this enabled and turned on; there is
1674 also a small increase in the kernel size if this is enabled.
1678 config X86_INTEL_MPX
1679 prompt "Intel MPX (Memory Protection Extensions)"
1681 depends on CPU_SUP_INTEL
1683 MPX provides hardware features that can be used in
1684 conjunction with compiler-instrumented code to check
1685 memory references. It is designed to detect buffer
1686 overflow or underflow bugs.
1688 This option enables running applications which are
1689 instrumented or otherwise use MPX. It does not use MPX
1690 itself inside the kernel or to protect the kernel
1691 against bad memory references.
1693 Enabling this option will make the kernel larger:
1694 ~8k of kernel text and 36 bytes of data on a 64-bit
1695 defconfig. It adds a long to the 'mm_struct' which
1696 will increase the kernel memory overhead of each
1697 process and adds some branches to paths used during
1698 exec() and munmap().
1700 For details, see Documentation/x86/intel_mpx.txt
1705 bool "EFI runtime service support"
1708 select EFI_RUNTIME_WRAPPERS
1710 This enables the kernel to use EFI runtime services that are
1711 available (such as the EFI variable services).
1713 This option is only useful on systems that have EFI firmware.
1714 In addition, you should use the latest ELILO loader available
1715 at <http://elilo.sourceforge.net> in order to take advantage
1716 of EFI runtime services. However, even with this option, the
1717 resultant kernel should continue to boot on existing non-EFI
1721 bool "EFI stub support"
1722 depends on EFI && !X86_USE_3DNOW
1725 This kernel feature allows a bzImage to be loaded directly
1726 by EFI firmware without the use of a bootloader.
1728 See Documentation/efi-stub.txt for more information.
1731 bool "EFI mixed-mode support"
1732 depends on EFI_STUB && X86_64
1734 Enabling this feature allows a 64-bit kernel to be booted
1735 on a 32-bit firmware, provided that your CPU supports 64-bit
1738 Note that it is not possible to boot a mixed-mode enabled
1739 kernel via the EFI boot stub - a bootloader that supports
1740 the EFI handover protocol must be used.
1746 prompt "Enable seccomp to safely compute untrusted bytecode"
1748 This kernel feature is useful for number crunching applications
1749 that may need to compute untrusted bytecode during their
1750 execution. By using pipes or other transports made available to
1751 the process as file descriptors supporting the read/write
1752 syscalls, it's possible to isolate those applications in
1753 their own address space using seccomp. Once seccomp is
1754 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1755 and the task is only allowed to execute a few safe syscalls
1756 defined by each seccomp mode.
1758 If unsure, say Y. Only embedded should say N here.
1760 source kernel/Kconfig.hz
1763 bool "kexec system call"
1766 kexec is a system call that implements the ability to shutdown your
1767 current kernel, and to start another kernel. It is like a reboot
1768 but it is independent of the system firmware. And like a reboot
1769 you can start any kernel with it, not just Linux.
1771 The name comes from the similarity to the exec system call.
1773 It is an ongoing process to be certain the hardware in a machine
1774 is properly shutdown, so do not be surprised if this code does not
1775 initially work for you. As of this writing the exact hardware
1776 interface is strongly in flux, so no good recommendation can be
1780 bool "kexec file based system call"
1785 depends on CRYPTO_SHA256=y
1787 This is new version of kexec system call. This system call is
1788 file based and takes file descriptors as system call argument
1789 for kernel and initramfs as opposed to list of segments as
1790 accepted by previous system call.
1792 config KEXEC_VERIFY_SIG
1793 bool "Verify kernel signature during kexec_file_load() syscall"
1794 depends on KEXEC_FILE
1796 This option makes kernel signature verification mandatory for
1797 the kexec_file_load() syscall.
1799 In addition to that option, you need to enable signature
1800 verification for the corresponding kernel image type being
1801 loaded in order for this to work.
1803 config KEXEC_BZIMAGE_VERIFY_SIG
1804 bool "Enable bzImage signature verification support"
1805 depends on KEXEC_VERIFY_SIG
1806 depends on SIGNED_PE_FILE_VERIFICATION
1807 select SYSTEM_TRUSTED_KEYRING
1809 Enable bzImage signature verification support.
1812 bool "kernel crash dumps"
1813 depends on X86_64 || (X86_32 && HIGHMEM)
1815 Generate crash dump after being started by kexec.
1816 This should be normally only set in special crash dump kernels
1817 which are loaded in the main kernel with kexec-tools into
1818 a specially reserved region and then later executed after
1819 a crash by kdump/kexec. The crash dump kernel must be compiled
1820 to a memory address not used by the main kernel or BIOS using
1821 PHYSICAL_START, or it must be built as a relocatable image
1822 (CONFIG_RELOCATABLE=y).
1823 For more details see Documentation/kdump/kdump.txt
1827 depends on KEXEC && HIBERNATION
1829 Jump between original kernel and kexeced kernel and invoke
1830 code in physical address mode via KEXEC
1832 config PHYSICAL_START
1833 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1836 This gives the physical address where the kernel is loaded.
1838 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1839 bzImage will decompress itself to above physical address and
1840 run from there. Otherwise, bzImage will run from the address where
1841 it has been loaded by the boot loader and will ignore above physical
1844 In normal kdump cases one does not have to set/change this option
1845 as now bzImage can be compiled as a completely relocatable image
1846 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1847 address. This option is mainly useful for the folks who don't want
1848 to use a bzImage for capturing the crash dump and want to use a
1849 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1850 to be specifically compiled to run from a specific memory area
1851 (normally a reserved region) and this option comes handy.
1853 So if you are using bzImage for capturing the crash dump,
1854 leave the value here unchanged to 0x1000000 and set
1855 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1856 for capturing the crash dump change this value to start of
1857 the reserved region. In other words, it can be set based on
1858 the "X" value as specified in the "crashkernel=YM@XM"
1859 command line boot parameter passed to the panic-ed
1860 kernel. Please take a look at Documentation/kdump/kdump.txt
1861 for more details about crash dumps.
1863 Usage of bzImage for capturing the crash dump is recommended as
1864 one does not have to build two kernels. Same kernel can be used
1865 as production kernel and capture kernel. Above option should have
1866 gone away after relocatable bzImage support is introduced. But it
1867 is present because there are users out there who continue to use
1868 vmlinux for dump capture. This option should go away down the
1871 Don't change this unless you know what you are doing.
1874 bool "Build a relocatable kernel"
1877 This builds a kernel image that retains relocation information
1878 so it can be loaded someplace besides the default 1MB.
1879 The relocations tend to make the kernel binary about 10% larger,
1880 but are discarded at runtime.
1882 One use is for the kexec on panic case where the recovery kernel
1883 must live at a different physical address than the primary
1886 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1887 it has been loaded at and the compile time physical address
1888 (CONFIG_PHYSICAL_START) is used as the minimum location.
1890 config RANDOMIZE_BASE
1891 bool "Randomize the address of the kernel image"
1892 depends on RELOCATABLE
1895 Randomizes the physical and virtual address at which the
1896 kernel image is decompressed, as a security feature that
1897 deters exploit attempts relying on knowledge of the location
1898 of kernel internals.
1900 Entropy is generated using the RDRAND instruction if it is
1901 supported. If RDTSC is supported, it is used as well. If
1902 neither RDRAND nor RDTSC are supported, then randomness is
1903 read from the i8254 timer.
1905 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1906 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1907 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1908 minimum of 2MiB, only 10 bits of entropy is theoretically
1909 possible. At best, due to page table layouts, 64-bit can use
1910 9 bits of entropy and 32-bit uses 8 bits.
1914 config RANDOMIZE_BASE_MAX_OFFSET
1915 hex "Maximum kASLR offset allowed" if EXPERT
1916 depends on RANDOMIZE_BASE
1917 range 0x0 0x20000000 if X86_32
1918 default "0x20000000" if X86_32
1919 range 0x0 0x40000000 if X86_64
1920 default "0x40000000" if X86_64
1922 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1923 memory is used to determine the maximal offset in bytes that will
1924 be applied to the kernel when kernel Address Space Layout
1925 Randomization (kASLR) is active. This must be a multiple of
1928 On 32-bit this is limited to 512MiB by page table layouts. The
1931 On 64-bit this is limited by how the kernel fixmap page table is
1932 positioned, so this cannot be larger than 1GiB currently. Without
1933 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1934 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1935 modules area will shrink to compensate, up to the current maximum
1936 1GiB to 1GiB split. The default is 1GiB.
1938 If unsure, leave at the default value.
1940 # Relocation on x86 needs some additional build support
1941 config X86_NEED_RELOCS
1943 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1945 config PHYSICAL_ALIGN
1946 hex "Alignment value to which kernel should be aligned"
1948 range 0x2000 0x1000000 if X86_32
1949 range 0x200000 0x1000000 if X86_64
1951 This value puts the alignment restrictions on physical address
1952 where kernel is loaded and run from. Kernel is compiled for an
1953 address which meets above alignment restriction.
1955 If bootloader loads the kernel at a non-aligned address and
1956 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1957 address aligned to above value and run from there.
1959 If bootloader loads the kernel at a non-aligned address and
1960 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1961 load address and decompress itself to the address it has been
1962 compiled for and run from there. The address for which kernel is
1963 compiled already meets above alignment restrictions. Hence the
1964 end result is that kernel runs from a physical address meeting
1965 above alignment restrictions.
1967 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1968 this value must be a multiple of 0x200000.
1970 Don't change this unless you know what you are doing.
1973 bool "Support for hot-pluggable CPUs"
1976 Say Y here to allow turning CPUs off and on. CPUs can be
1977 controlled through /sys/devices/system/cpu.
1978 ( Note: power management support will enable this option
1979 automatically on SMP systems. )
1980 Say N if you want to disable CPU hotplug.
1982 config BOOTPARAM_HOTPLUG_CPU0
1983 bool "Set default setting of cpu0_hotpluggable"
1985 depends on HOTPLUG_CPU
1987 Set whether default state of cpu0_hotpluggable is on or off.
1989 Say Y here to enable CPU0 hotplug by default. If this switch
1990 is turned on, there is no need to give cpu0_hotplug kernel
1991 parameter and the CPU0 hotplug feature is enabled by default.
1993 Please note: there are two known CPU0 dependencies if you want
1994 to enable the CPU0 hotplug feature either by this switch or by
1995 cpu0_hotplug kernel parameter.
1997 First, resume from hibernate or suspend always starts from CPU0.
1998 So hibernate and suspend are prevented if CPU0 is offline.
2000 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2001 offline if any interrupt can not migrate out of CPU0. There may
2002 be other CPU0 dependencies.
2004 Please make sure the dependencies are under your control before
2005 you enable this feature.
2007 Say N if you don't want to enable CPU0 hotplug feature by default.
2008 You still can enable the CPU0 hotplug feature at boot by kernel
2009 parameter cpu0_hotplug.
2011 config DEBUG_HOTPLUG_CPU0
2013 prompt "Debug CPU0 hotplug"
2014 depends on HOTPLUG_CPU
2016 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2017 soon as possible and boots up userspace with CPU0 offlined. User
2018 can online CPU0 back after boot time.
2020 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2021 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2022 compilation or giving cpu0_hotplug kernel parameter at boot.
2028 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2029 depends on X86_32 || IA32_EMULATION
2031 Certain buggy versions of glibc will crash if they are
2032 presented with a 32-bit vDSO that is not mapped at the address
2033 indicated in its segment table.
2035 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2036 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2037 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2038 the only released version with the bug, but OpenSUSE 9
2039 contains a buggy "glibc 2.3.2".
2041 The symptom of the bug is that everything crashes on startup, saying:
2042 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2044 Saying Y here changes the default value of the vdso32 boot
2045 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2046 This works around the glibc bug but hurts performance.
2048 If unsure, say N: if you are compiling your own kernel, you
2049 are unlikely to be using a buggy version of glibc.
2052 prompt "vsyscall table for legacy applications"
2054 default LEGACY_VSYSCALL_EMULATE
2056 Legacy user code that does not know how to find the vDSO expects
2057 to be able to issue three syscalls by calling fixed addresses in
2058 kernel space. Since this location is not randomized with ASLR,
2059 it can be used to assist security vulnerability exploitation.
2061 This setting can be changed at boot time via the kernel command
2062 line parameter vsyscall=[native|emulate|none].
2064 On a system with recent enough glibc (2.14 or newer) and no
2065 static binaries, you can say None without a performance penalty
2066 to improve security.
2068 If unsure, select "Emulate".
2070 config LEGACY_VSYSCALL_NATIVE
2073 Actual executable code is located in the fixed vsyscall
2074 address mapping, implementing time() efficiently. Since
2075 this makes the mapping executable, it can be used during
2076 security vulnerability exploitation (traditionally as
2077 ROP gadgets). This configuration is not recommended.
2079 config LEGACY_VSYSCALL_EMULATE
2082 The kernel traps and emulates calls into the fixed
2083 vsyscall address mapping. This makes the mapping
2084 non-executable, but it still contains known contents,
2085 which could be used in certain rare security vulnerability
2086 exploits. This configuration is recommended when userspace
2087 still uses the vsyscall area.
2089 config LEGACY_VSYSCALL_NONE
2092 There will be no vsyscall mapping at all. This will
2093 eliminate any risk of ASLR bypass due to the vsyscall
2094 fixed address mapping. Attempts to use the vsyscalls
2095 will be reported to dmesg, so that either old or
2096 malicious userspace programs can be identified.
2101 bool "Built-in kernel command line"
2103 Allow for specifying boot arguments to the kernel at
2104 build time. On some systems (e.g. embedded ones), it is
2105 necessary or convenient to provide some or all of the
2106 kernel boot arguments with the kernel itself (that is,
2107 to not rely on the boot loader to provide them.)
2109 To compile command line arguments into the kernel,
2110 set this option to 'Y', then fill in the
2111 boot arguments in CONFIG_CMDLINE.
2113 Systems with fully functional boot loaders (i.e. non-embedded)
2114 should leave this option set to 'N'.
2117 string "Built-in kernel command string"
2118 depends on CMDLINE_BOOL
2121 Enter arguments here that should be compiled into the kernel
2122 image and used at boot time. If the boot loader provides a
2123 command line at boot time, it is appended to this string to
2124 form the full kernel command line, when the system boots.
2126 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2127 change this behavior.
2129 In most cases, the command line (whether built-in or provided
2130 by the boot loader) should specify the device for the root
2133 config CMDLINE_OVERRIDE
2134 bool "Built-in command line overrides boot loader arguments"
2135 depends on CMDLINE_BOOL
2137 Set this option to 'Y' to have the kernel ignore the boot loader
2138 command line, and use ONLY the built-in command line.
2140 This is used to work around broken boot loaders. This should
2141 be set to 'N' under normal conditions.
2143 config MODIFY_LDT_SYSCALL
2144 bool "Enable the LDT (local descriptor table)" if EXPERT
2147 Linux can allow user programs to install a per-process x86
2148 Local Descriptor Table (LDT) using the modify_ldt(2) system
2149 call. This is required to run 16-bit or segmented code such as
2150 DOSEMU or some Wine programs. It is also used by some very old
2151 threading libraries.
2153 Enabling this feature adds a small amount of overhead to
2154 context switches and increases the low-level kernel attack
2155 surface. Disabling it removes the modify_ldt(2) system call.
2157 Saying 'N' here may make sense for embedded or server kernels.
2159 source "kernel/livepatch/Kconfig"
2163 config ARCH_ENABLE_MEMORY_HOTPLUG
2165 depends on X86_64 || (X86_32 && HIGHMEM)
2167 config ARCH_ENABLE_MEMORY_HOTREMOVE
2169 depends on MEMORY_HOTPLUG
2171 config USE_PERCPU_NUMA_NODE_ID
2175 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2177 depends on X86_64 || X86_PAE
2179 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2181 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2183 menu "Power management and ACPI options"
2185 config ARCH_HIBERNATION_HEADER
2187 depends on X86_64 && HIBERNATION
2189 source "kernel/power/Kconfig"
2191 source "drivers/acpi/Kconfig"
2193 source "drivers/sfi/Kconfig"
2200 tristate "APM (Advanced Power Management) BIOS support"
2201 depends on X86_32 && PM_SLEEP
2203 APM is a BIOS specification for saving power using several different
2204 techniques. This is mostly useful for battery powered laptops with
2205 APM compliant BIOSes. If you say Y here, the system time will be
2206 reset after a RESUME operation, the /proc/apm device will provide
2207 battery status information, and user-space programs will receive
2208 notification of APM "events" (e.g. battery status change).
2210 If you select "Y" here, you can disable actual use of the APM
2211 BIOS by passing the "apm=off" option to the kernel at boot time.
2213 Note that the APM support is almost completely disabled for
2214 machines with more than one CPU.
2216 In order to use APM, you will need supporting software. For location
2217 and more information, read <file:Documentation/power/apm-acpi.txt>
2218 and the Battery Powered Linux mini-HOWTO, available from
2219 <http://www.tldp.org/docs.html#howto>.
2221 This driver does not spin down disk drives (see the hdparm(8)
2222 manpage ("man 8 hdparm") for that), and it doesn't turn off
2223 VESA-compliant "green" monitors.
2225 This driver does not support the TI 4000M TravelMate and the ACER
2226 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2227 desktop machines also don't have compliant BIOSes, and this driver
2228 may cause those machines to panic during the boot phase.
2230 Generally, if you don't have a battery in your machine, there isn't
2231 much point in using this driver and you should say N. If you get
2232 random kernel OOPSes or reboots that don't seem to be related to
2233 anything, try disabling/enabling this option (or disabling/enabling
2236 Some other things you should try when experiencing seemingly random,
2239 1) make sure that you have enough swap space and that it is
2241 2) pass the "no-hlt" option to the kernel
2242 3) switch on floating point emulation in the kernel and pass
2243 the "no387" option to the kernel
2244 4) pass the "floppy=nodma" option to the kernel
2245 5) pass the "mem=4M" option to the kernel (thereby disabling
2246 all but the first 4 MB of RAM)
2247 6) make sure that the CPU is not over clocked.
2248 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2249 8) disable the cache from your BIOS settings
2250 9) install a fan for the video card or exchange video RAM
2251 10) install a better fan for the CPU
2252 11) exchange RAM chips
2253 12) exchange the motherboard.
2255 To compile this driver as a module, choose M here: the
2256 module will be called apm.
2260 config APM_IGNORE_USER_SUSPEND
2261 bool "Ignore USER SUSPEND"
2263 This option will ignore USER SUSPEND requests. On machines with a
2264 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2265 series notebooks, it is necessary to say Y because of a BIOS bug.
2267 config APM_DO_ENABLE
2268 bool "Enable PM at boot time"
2270 Enable APM features at boot time. From page 36 of the APM BIOS
2271 specification: "When disabled, the APM BIOS does not automatically
2272 power manage devices, enter the Standby State, enter the Suspend
2273 State, or take power saving steps in response to CPU Idle calls."
2274 This driver will make CPU Idle calls when Linux is idle (unless this
2275 feature is turned off -- see "Do CPU IDLE calls", below). This
2276 should always save battery power, but more complicated APM features
2277 will be dependent on your BIOS implementation. You may need to turn
2278 this option off if your computer hangs at boot time when using APM
2279 support, or if it beeps continuously instead of suspending. Turn
2280 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2281 T400CDT. This is off by default since most machines do fine without
2286 bool "Make CPU Idle calls when idle"
2288 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2289 On some machines, this can activate improved power savings, such as
2290 a slowed CPU clock rate, when the machine is idle. These idle calls
2291 are made after the idle loop has run for some length of time (e.g.,
2292 333 mS). On some machines, this will cause a hang at boot time or
2293 whenever the CPU becomes idle. (On machines with more than one CPU,
2294 this option does nothing.)
2296 config APM_DISPLAY_BLANK
2297 bool "Enable console blanking using APM"
2299 Enable console blanking using the APM. Some laptops can use this to
2300 turn off the LCD backlight when the screen blanker of the Linux
2301 virtual console blanks the screen. Note that this is only used by
2302 the virtual console screen blanker, and won't turn off the backlight
2303 when using the X Window system. This also doesn't have anything to
2304 do with your VESA-compliant power-saving monitor. Further, this
2305 option doesn't work for all laptops -- it might not turn off your
2306 backlight at all, or it might print a lot of errors to the console,
2307 especially if you are using gpm.
2309 config APM_ALLOW_INTS
2310 bool "Allow interrupts during APM BIOS calls"
2312 Normally we disable external interrupts while we are making calls to
2313 the APM BIOS as a measure to lessen the effects of a badly behaving
2314 BIOS implementation. The BIOS should reenable interrupts if it
2315 needs to. Unfortunately, some BIOSes do not -- especially those in
2316 many of the newer IBM Thinkpads. If you experience hangs when you
2317 suspend, try setting this to Y. Otherwise, say N.
2321 source "drivers/cpufreq/Kconfig"
2323 source "drivers/cpuidle/Kconfig"
2325 source "drivers/idle/Kconfig"
2330 menu "Bus options (PCI etc.)"
2336 Find out whether you have a PCI motherboard. PCI is the name of a
2337 bus system, i.e. the way the CPU talks to the other stuff inside
2338 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2339 VESA. If you have PCI, say Y, otherwise N.
2342 prompt "PCI access mode"
2343 depends on X86_32 && PCI
2346 On PCI systems, the BIOS can be used to detect the PCI devices and
2347 determine their configuration. However, some old PCI motherboards
2348 have BIOS bugs and may crash if this is done. Also, some embedded
2349 PCI-based systems don't have any BIOS at all. Linux can also try to
2350 detect the PCI hardware directly without using the BIOS.
2352 With this option, you can specify how Linux should detect the
2353 PCI devices. If you choose "BIOS", the BIOS will be used,
2354 if you choose "Direct", the BIOS won't be used, and if you
2355 choose "MMConfig", then PCI Express MMCONFIG will be used.
2356 If you choose "Any", the kernel will try MMCONFIG, then the
2357 direct access method and falls back to the BIOS if that doesn't
2358 work. If unsure, go with the default, which is "Any".
2363 config PCI_GOMMCONFIG
2380 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2382 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2385 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2389 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2393 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2397 depends on PCI && XEN
2405 bool "Support mmconfig PCI config space access"
2406 depends on X86_64 && PCI && ACPI
2408 config PCI_CNB20LE_QUIRK
2409 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2412 Read the PCI windows out of the CNB20LE host bridge. This allows
2413 PCI hotplug to work on systems with the CNB20LE chipset which do
2416 There's no public spec for this chipset, and this functionality
2417 is known to be incomplete.
2419 You should say N unless you know you need this.
2421 source "drivers/pci/pcie/Kconfig"
2423 source "drivers/pci/Kconfig"
2425 # x86_64 have no ISA slots, but can have ISA-style DMA.
2427 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2430 Enables ISA-style DMA support for devices requiring such controllers.
2438 Find out whether you have ISA slots on your motherboard. ISA is the
2439 name of a bus system, i.e. the way the CPU talks to the other stuff
2440 inside your box. Other bus systems are PCI, EISA, MicroChannel
2441 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2442 newer boards don't support it. If you have ISA, say Y, otherwise N.
2448 The Extended Industry Standard Architecture (EISA) bus was
2449 developed as an open alternative to the IBM MicroChannel bus.
2451 The EISA bus provided some of the features of the IBM MicroChannel
2452 bus while maintaining backward compatibility with cards made for
2453 the older ISA bus. The EISA bus saw limited use between 1988 and
2454 1995 when it was made obsolete by the PCI bus.
2456 Say Y here if you are building a kernel for an EISA-based machine.
2460 source "drivers/eisa/Kconfig"
2463 tristate "NatSemi SCx200 support"
2465 This provides basic support for National Semiconductor's
2466 (now AMD's) Geode processors. The driver probes for the
2467 PCI-IDs of several on-chip devices, so its a good dependency
2468 for other scx200_* drivers.
2470 If compiled as a module, the driver is named scx200.
2472 config SCx200HR_TIMER
2473 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2477 This driver provides a clocksource built upon the on-chip
2478 27MHz high-resolution timer. Its also a workaround for
2479 NSC Geode SC-1100's buggy TSC, which loses time when the
2480 processor goes idle (as is done by the scheduler). The
2481 other workaround is idle=poll boot option.
2484 bool "One Laptop Per Child support"
2491 Add support for detecting the unique features of the OLPC
2495 bool "OLPC XO-1 Power Management"
2496 depends on OLPC && MFD_CS5535 && PM_SLEEP
2499 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2502 bool "OLPC XO-1 Real Time Clock"
2503 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2505 Add support for the XO-1 real time clock, which can be used as a
2506 programmable wakeup source.
2509 bool "OLPC XO-1 SCI extras"
2510 depends on OLPC && OLPC_XO1_PM
2516 Add support for SCI-based features of the OLPC XO-1 laptop:
2517 - EC-driven system wakeups
2521 - AC adapter status updates
2522 - Battery status updates
2524 config OLPC_XO15_SCI
2525 bool "OLPC XO-1.5 SCI extras"
2526 depends on OLPC && ACPI
2529 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2530 - EC-driven system wakeups
2531 - AC adapter status updates
2532 - Battery status updates
2535 bool "PCEngines ALIX System Support (LED setup)"
2538 This option enables system support for the PCEngines ALIX.
2539 At present this just sets up LEDs for GPIO control on
2540 ALIX2/3/6 boards. However, other system specific setup should
2543 Note: You must still enable the drivers for GPIO and LED support
2544 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2546 Note: You have to set alix.force=1 for boards with Award BIOS.
2549 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2552 This option enables system support for the Soekris Engineering net5501.
2555 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2559 This option enables system support for the Traverse Technologies GEOS.
2562 bool "Technologic Systems TS-5500 platform support"
2564 select CHECK_SIGNATURE
2568 This option enables system support for the Technologic Systems TS-5500.
2574 depends on CPU_SUP_AMD && PCI
2576 source "drivers/pcmcia/Kconfig"
2578 source "drivers/pci/hotplug/Kconfig"
2581 tristate "RapidIO support"
2585 If enabled this option will include drivers and the core
2586 infrastructure code to support RapidIO interconnect devices.
2588 source "drivers/rapidio/Kconfig"
2591 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2593 Firmwares often provide initial graphics framebuffers so the BIOS,
2594 bootloader or kernel can show basic video-output during boot for
2595 user-guidance and debugging. Historically, x86 used the VESA BIOS
2596 Extensions and EFI-framebuffers for this, which are mostly limited
2598 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2599 framebuffers so the new generic system-framebuffer drivers can be
2600 used on x86. If the framebuffer is not compatible with the generic
2601 modes, it is adverticed as fallback platform framebuffer so legacy
2602 drivers like efifb, vesafb and uvesafb can pick it up.
2603 If this option is not selected, all system framebuffers are always
2604 marked as fallback platform framebuffers as usual.
2606 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2607 not be able to pick up generic system framebuffers if this option
2608 is selected. You are highly encouraged to enable simplefb as
2609 replacement if you select this option. simplefb can correctly deal
2610 with generic system framebuffers. But you should still keep vesafb
2611 and others enabled as fallback if a system framebuffer is
2612 incompatible with simplefb.
2619 menu "Executable file formats / Emulations"
2621 source "fs/Kconfig.binfmt"
2623 config IA32_EMULATION
2624 bool "IA32 Emulation"
2627 select COMPAT_BINFMT_ELF
2628 select ARCH_WANT_OLD_COMPAT_IPC
2630 Include code to run legacy 32-bit programs under a
2631 64-bit kernel. You should likely turn this on, unless you're
2632 100% sure that you don't have any 32-bit programs left.
2635 tristate "IA32 a.out support"
2636 depends on IA32_EMULATION
2638 Support old a.out binaries in the 32bit emulation.
2641 bool "x32 ABI for 64-bit mode"
2644 Include code to run binaries for the x32 native 32-bit ABI
2645 for 64-bit processors. An x32 process gets access to the
2646 full 64-bit register file and wide data path while leaving
2647 pointers at 32 bits for smaller memory footprint.
2649 You will need a recent binutils (2.22 or later) with
2650 elf32_x86_64 support enabled to compile a kernel with this
2655 depends on IA32_EMULATION || X86_X32
2658 config COMPAT_FOR_U64_ALIGNMENT
2661 config SYSVIPC_COMPAT
2673 config HAVE_ATOMIC_IOMAP
2677 config X86_DEV_DMA_OPS
2679 depends on X86_64 || STA2X11
2681 config X86_DMA_REMAP
2689 source "net/Kconfig"
2691 source "drivers/Kconfig"
2693 source "drivers/firmware/Kconfig"
2697 source "arch/x86/Kconfig.debug"
2699 source "security/Kconfig"
2701 source "crypto/Kconfig"
2703 source "arch/x86/kvm/Kconfig"
2705 source "lib/Kconfig"