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_HUGE_VMAP if X86_64 || X86_PAE
83 select HAVE_ARCH_JUMP_LABEL
84 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
86 select HAVE_ARCH_KMEMCHECK
87 select HAVE_ARCH_SECCOMP_FILTER
88 select HAVE_ARCH_SOFT_DIRTY if X86_64
89 select HAVE_ARCH_TRACEHOOK
90 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
91 select HAVE_BPF_JIT if X86_64
92 select HAVE_CC_STACKPROTECTOR
93 select HAVE_CMPXCHG_DOUBLE
94 select HAVE_CMPXCHG_LOCAL
95 select HAVE_CONTEXT_TRACKING if X86_64
96 select HAVE_COPY_THREAD_TLS
97 select HAVE_C_RECORDMCOUNT
98 select HAVE_DEBUG_KMEMLEAK
99 select HAVE_DEBUG_STACKOVERFLOW
100 select HAVE_DMA_API_DEBUG
101 select HAVE_DMA_ATTRS
102 select HAVE_DMA_CONTIGUOUS
103 select HAVE_DYNAMIC_FTRACE
104 select HAVE_DYNAMIC_FTRACE_WITH_REGS
105 select HAVE_EFFICIENT_UNALIGNED_ACCESS
106 select HAVE_FENTRY if X86_64
107 select HAVE_FTRACE_MCOUNT_RECORD
108 select HAVE_FUNCTION_GRAPH_FP_TEST
109 select HAVE_FUNCTION_GRAPH_TRACER
110 select HAVE_FUNCTION_TRACER
111 select HAVE_GENERIC_DMA_COHERENT if X86_32
112 select HAVE_HW_BREAKPOINT
114 select HAVE_IOREMAP_PROT
115 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
116 select HAVE_IRQ_TIME_ACCOUNTING
117 select HAVE_KERNEL_BZIP2
118 select HAVE_KERNEL_GZIP
119 select HAVE_KERNEL_LZ4
120 select HAVE_KERNEL_LZMA
121 select HAVE_KERNEL_LZO
122 select HAVE_KERNEL_XZ
124 select HAVE_KPROBES_ON_FTRACE
125 select HAVE_KRETPROBES
127 select HAVE_LIVEPATCH if X86_64
129 select HAVE_MEMBLOCK_NODE_MAP
130 select HAVE_MIXED_BREAKPOINTS_REGS
132 select HAVE_OPTPROBES
133 select HAVE_PCSPKR_PLATFORM
134 select HAVE_PERF_EVENTS
135 select HAVE_PERF_EVENTS_NMI
136 select HAVE_PERF_REGS
137 select HAVE_PERF_USER_STACK_DUMP
138 select HAVE_REGS_AND_STACK_ACCESS_API
139 select HAVE_SYSCALL_TRACEPOINTS
140 select HAVE_UID16 if X86_32 || IA32_EMULATION
141 select HAVE_UNSTABLE_SCHED_CLOCK
142 select HAVE_USER_RETURN_NOTIFIER
143 select IRQ_FORCED_THREADING
144 select MODULES_USE_ELF_RELA if X86_64
145 select MODULES_USE_ELF_REL if X86_32
146 select OLD_SIGACTION if X86_32
147 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
152 select SYSCTL_EXCEPTION_TRACE
153 select USER_STACKTRACE_SUPPORT
155 select X86_DEV_DMA_OPS if X86_64
156 select X86_FEATURE_NAMES if PROC_FS
158 config INSTRUCTION_DECODER
160 depends on KPROBES || PERF_EVENTS || UPROBES
162 config PERF_EVENTS_INTEL_UNCORE
164 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
168 default "elf32-i386" if X86_32
169 default "elf64-x86-64" if X86_64
171 config ARCH_DEFCONFIG
173 default "arch/x86/configs/i386_defconfig" if X86_32
174 default "arch/x86/configs/x86_64_defconfig" if X86_64
176 config LOCKDEP_SUPPORT
179 config STACKTRACE_SUPPORT
182 config HAVE_LATENCYTOP_SUPPORT
188 config ARCH_MMAP_RND_BITS_MIN
192 config ARCH_MMAP_RND_BITS_MAX
196 config ARCH_MMAP_RND_COMPAT_BITS_MIN
199 config ARCH_MMAP_RND_COMPAT_BITS_MAX
205 config NEED_DMA_MAP_STATE
207 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
209 config NEED_SG_DMA_LENGTH
212 config GENERIC_ISA_DMA
214 depends on ISA_DMA_API
219 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
221 config GENERIC_BUG_RELATIVE_POINTERS
224 config GENERIC_HWEIGHT
227 config ARCH_MAY_HAVE_PC_FDC
229 depends on ISA_DMA_API
231 config RWSEM_XCHGADD_ALGORITHM
234 config GENERIC_CALIBRATE_DELAY
237 config ARCH_HAS_CPU_RELAX
240 config ARCH_HAS_CACHE_LINE_SIZE
243 config HAVE_SETUP_PER_CPU_AREA
246 config NEED_PER_CPU_EMBED_FIRST_CHUNK
249 config NEED_PER_CPU_PAGE_FIRST_CHUNK
252 config ARCH_HIBERNATION_POSSIBLE
255 config ARCH_SUSPEND_POSSIBLE
258 config ARCH_WANT_HUGE_PMD_SHARE
261 config ARCH_WANT_GENERAL_HUGETLB
270 config ARCH_SUPPORTS_OPTIMIZED_INLINING
273 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
276 config KASAN_SHADOW_OFFSET
279 default 0xdffffc0000000000
281 config HAVE_INTEL_TXT
283 depends on INTEL_IOMMU && ACPI
287 depends on X86_32 && SMP
291 depends on X86_64 && SMP
293 config X86_32_LAZY_GS
295 depends on X86_32 && !CC_STACKPROTECTOR
297 config ARCH_HWEIGHT_CFLAGS
299 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
300 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
302 config ARCH_SUPPORTS_UPROBES
305 config FIX_EARLYCON_MEM
308 config PGTABLE_LEVELS
314 source "init/Kconfig"
315 source "kernel/Kconfig.freezer"
317 menu "Processor type and features"
320 bool "DMA memory allocation support" if EXPERT
323 DMA memory allocation support allows devices with less than 32-bit
324 addressing to allocate within the first 16MB of address space.
325 Disable if no such devices will be used.
330 bool "Symmetric multi-processing support"
332 This enables support for systems with more than one CPU. If you have
333 a system with only one CPU, say N. If you have a system with more
336 If you say N here, the kernel will run on uni- and multiprocessor
337 machines, but will use only one CPU of a multiprocessor machine. If
338 you say Y here, the kernel will run on many, but not all,
339 uniprocessor machines. On a uniprocessor machine, the kernel
340 will run faster if you say N here.
342 Note that if you say Y here and choose architecture "586" or
343 "Pentium" under "Processor family", the kernel will not work on 486
344 architectures. Similarly, multiprocessor kernels for the "PPro"
345 architecture may not work on all Pentium based boards.
347 People using multiprocessor machines who say Y here should also say
348 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
349 Management" code will be disabled if you say Y here.
351 See also <file:Documentation/x86/i386/IO-APIC.txt>,
352 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
353 <http://www.tldp.org/docs.html#howto>.
355 If you don't know what to do here, say N.
357 config X86_FEATURE_NAMES
358 bool "Processor feature human-readable names" if EMBEDDED
361 This option compiles in a table of x86 feature bits and corresponding
362 names. This is required to support /proc/cpuinfo and a few kernel
363 messages. You can disable this to save space, at the expense of
364 making those few kernel messages show numeric feature bits instead.
369 bool "Support x2apic"
370 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
372 This enables x2apic support on CPUs that have this feature.
374 This allows 32-bit apic IDs (so it can support very large systems),
375 and accesses the local apic via MSRs not via mmio.
377 If you don't know what to do here, say N.
380 bool "Enable MPS table" if ACPI || SFI
382 depends on X86_LOCAL_APIC
384 For old smp systems that do not have proper acpi support. Newer systems
385 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
388 bool "Support for big SMP systems with more than 8 CPUs"
389 depends on X86_32 && SMP
391 This option is needed for the systems that have more than 8 CPUs
395 depends on X86_GOLDFISH
398 config X86_EXTENDED_PLATFORM
399 bool "Support for extended (non-PC) x86 platforms"
402 If you disable this option then the kernel will only support
403 standard PC platforms. (which covers the vast majority of
406 If you enable this option then you'll be able to select support
407 for the following (non-PC) 32 bit x86 platforms:
408 Goldfish (Android emulator)
411 SGI 320/540 (Visual Workstation)
412 STA2X11-based (e.g. Northville)
413 Moorestown MID devices
415 If you have one of these systems, or if you want to build a
416 generic distribution kernel, say Y here - otherwise say N.
420 config X86_EXTENDED_PLATFORM
421 bool "Support for extended (non-PC) x86 platforms"
424 If you disable this option then the kernel will only support
425 standard PC platforms. (which covers the vast majority of
428 If you enable this option then you'll be able to select support
429 for the following (non-PC) 64 bit x86 platforms:
434 If you have one of these systems, or if you want to build a
435 generic distribution kernel, say Y here - otherwise say N.
437 # This is an alphabetically sorted list of 64 bit extended platforms
438 # Please maintain the alphabetic order if and when there are additions
440 bool "Numascale NumaChip"
442 depends on X86_EXTENDED_PLATFORM
445 depends on X86_X2APIC
446 depends on PCI_MMCONFIG
448 Adds support for Numascale NumaChip large-SMP systems. Needed to
449 enable more than ~168 cores.
450 If you don't have one of these, you should say N here.
454 select HYPERVISOR_GUEST
456 depends on X86_64 && PCI
457 depends on X86_EXTENDED_PLATFORM
460 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
461 supposed to run on these EM64T-based machines. Only choose this option
462 if you have one of these machines.
465 bool "SGI Ultraviolet"
467 depends on X86_EXTENDED_PLATFORM
469 depends on X86_X2APIC
472 This option is needed in order to support SGI Ultraviolet systems.
473 If you don't have one of these, you should say N here.
475 # Following is an alphabetically sorted list of 32 bit extended platforms
476 # Please maintain the alphabetic order if and when there are additions
479 bool "Goldfish (Virtual Platform)"
480 depends on X86_EXTENDED_PLATFORM
482 Enable support for the Goldfish virtual platform used primarily
483 for Android development. Unless you are building for the Android
484 Goldfish emulator say N here.
487 bool "CE4100 TV platform"
489 depends on PCI_GODIRECT
490 depends on X86_IO_APIC
492 depends on X86_EXTENDED_PLATFORM
493 select X86_REBOOTFIXUPS
495 select OF_EARLY_FLATTREE
497 Select for the Intel CE media processor (CE4100) SOC.
498 This option compiles in support for the CE4100 SOC for settop
499 boxes and media devices.
502 bool "Intel MID platform support"
504 depends on X86_EXTENDED_PLATFORM
505 depends on X86_PLATFORM_DEVICES
508 depends on X86_IO_APIC
514 select MFD_INTEL_MSIC
516 Select to build a kernel capable of supporting Intel MID (Mobile
517 Internet Device) platform systems which do not have the PCI legacy
518 interfaces. If you are building for a PC class system say N here.
520 Intel MID platforms are based on an Intel processor and chipset which
521 consume less power than most of the x86 derivatives.
523 config X86_INTEL_QUARK
524 bool "Intel Quark platform support"
526 depends on X86_EXTENDED_PLATFORM
527 depends on X86_PLATFORM_DEVICES
531 depends on X86_IO_APIC
536 Select to include support for Quark X1000 SoC.
537 Say Y here if you have a Quark based system such as the Arduino
538 compatible Intel Galileo.
540 config X86_INTEL_LPSS
541 bool "Intel Low Power Subsystem Support"
546 Select to build support for Intel Low Power Subsystem such as
547 found on Intel Lynxpoint PCH. Selecting this option enables
548 things like clock tree (common clock framework) and pincontrol
549 which are needed by the LPSS peripheral drivers.
551 config X86_AMD_PLATFORM_DEVICE
552 bool "AMD ACPI2Platform devices support"
557 Select to interpret AMD specific ACPI device to platform device
558 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
559 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
560 implemented under PINCTRL subsystem.
563 tristate "Intel SoC IOSF Sideband support for SoC platforms"
566 This option enables sideband register access support for Intel SoC
567 platforms. On these platforms the IOSF sideband is used in lieu of
568 MSR's for some register accesses, mostly but not limited to thermal
569 and power. Drivers may query the availability of this device to
570 determine if they need the sideband in order to work on these
571 platforms. The sideband is available on the following SoC products.
572 This list is not meant to be exclusive.
577 You should say Y if you are running a kernel on one of these SoC's.
579 config IOSF_MBI_DEBUG
580 bool "Enable IOSF sideband access through debugfs"
581 depends on IOSF_MBI && DEBUG_FS
583 Select this option to expose the IOSF sideband access registers (MCR,
584 MDR, MCRX) through debugfs to write and read register information from
585 different units on the SoC. This is most useful for obtaining device
586 state information for debug and analysis. As this is a general access
587 mechanism, users of this option would have specific knowledge of the
588 device they want to access.
590 If you don't require the option or are in doubt, say N.
593 bool "RDC R-321x SoC"
595 depends on X86_EXTENDED_PLATFORM
597 select X86_REBOOTFIXUPS
599 This option is needed for RDC R-321x system-on-chip, also known
601 If you don't have one of these chips, you should say N here.
603 config X86_32_NON_STANDARD
604 bool "Support non-standard 32-bit SMP architectures"
605 depends on X86_32 && SMP
606 depends on X86_EXTENDED_PLATFORM
608 This option compiles in the bigsmp and STA2X11 default
609 subarchitectures. It is intended for a generic binary
610 kernel. If you select them all, kernel will probe it one by
611 one and will fallback to default.
613 # Alphabetically sorted list of Non standard 32 bit platforms
615 config X86_SUPPORTS_MEMORY_FAILURE
617 # MCE code calls memory_failure():
619 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
620 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
621 depends on X86_64 || !SPARSEMEM
622 select ARCH_SUPPORTS_MEMORY_FAILURE
625 bool "STA2X11 Companion Chip Support"
626 depends on X86_32_NON_STANDARD && PCI
627 select X86_DEV_DMA_OPS
631 select ARCH_REQUIRE_GPIOLIB
634 This adds support for boards based on the STA2X11 IO-Hub,
635 a.k.a. "ConneXt". The chip is used in place of the standard
636 PC chipset, so all "standard" peripherals are missing. If this
637 option is selected the kernel will still be able to boot on
638 standard PC machines.
641 tristate "Eurobraille/Iris poweroff module"
644 The Iris machines from EuroBraille do not have APM or ACPI support
645 to shut themselves down properly. A special I/O sequence is
646 needed to do so, which is what this module does at
649 This is only for Iris machines from EuroBraille.
653 config SCHED_OMIT_FRAME_POINTER
655 prompt "Single-depth WCHAN output"
658 Calculate simpler /proc/<PID>/wchan values. If this option
659 is disabled then wchan values will recurse back to the
660 caller function. This provides more accurate wchan values,
661 at the expense of slightly more scheduling overhead.
663 If in doubt, say "Y".
665 menuconfig HYPERVISOR_GUEST
666 bool "Linux guest support"
668 Say Y here to enable options for running Linux under various hyper-
669 visors. This option enables basic hypervisor detection and platform
672 If you say N, all options in this submenu will be skipped and
673 disabled, and Linux guest support won't be built in.
678 bool "Enable paravirtualization code"
680 This changes the kernel so it can modify itself when it is run
681 under a hypervisor, potentially improving performance significantly
682 over full virtualization. However, when run without a hypervisor
683 the kernel is theoretically slower and slightly larger.
685 config PARAVIRT_DEBUG
686 bool "paravirt-ops debugging"
687 depends on PARAVIRT && DEBUG_KERNEL
689 Enable to debug paravirt_ops internals. Specifically, BUG if
690 a paravirt_op is missing when it is called.
692 config PARAVIRT_SPINLOCKS
693 bool "Paravirtualization layer for spinlocks"
694 depends on PARAVIRT && SMP
695 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
697 Paravirtualized spinlocks allow a pvops backend to replace the
698 spinlock implementation with something virtualization-friendly
699 (for example, block the virtual CPU rather than spinning).
701 It has a minimal impact on native kernels and gives a nice performance
702 benefit on paravirtualized KVM / Xen kernels.
704 If you are unsure how to answer this question, answer Y.
706 source "arch/x86/xen/Kconfig"
709 bool "KVM Guest support (including kvmclock)"
711 select PARAVIRT_CLOCK
714 This option enables various optimizations for running under the KVM
715 hypervisor. It includes a paravirtualized clock, so that instead
716 of relying on a PIT (or probably other) emulation by the
717 underlying device model, the host provides the guest with
718 timing infrastructure such as time of day, and system time
721 bool "Enable debug information for KVM Guests in debugfs"
722 depends on KVM_GUEST && DEBUG_FS
725 This option enables collection of various statistics for KVM guest.
726 Statistics are displayed in debugfs filesystem. Enabling this option
727 may incur significant overhead.
729 source "arch/x86/lguest/Kconfig"
731 config PARAVIRT_TIME_ACCOUNTING
732 bool "Paravirtual steal time accounting"
736 Select this option to enable fine granularity task steal time
737 accounting. Time spent executing other tasks in parallel with
738 the current vCPU is discounted from the vCPU power. To account for
739 that, there can be a small performance impact.
741 If in doubt, say N here.
743 config PARAVIRT_CLOCK
746 endif #HYPERVISOR_GUEST
751 source "arch/x86/Kconfig.cpu"
755 prompt "HPET Timer Support" if X86_32
757 Use the IA-PC HPET (High Precision Event Timer) to manage
758 time in preference to the PIT and RTC, if a HPET is
760 HPET is the next generation timer replacing legacy 8254s.
761 The HPET provides a stable time base on SMP
762 systems, unlike the TSC, but it is more expensive to access,
763 as it is off-chip. You can find the HPET spec at
764 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
766 You can safely choose Y here. However, HPET will only be
767 activated if the platform and the BIOS support this feature.
768 Otherwise the 8254 will be used for timing services.
770 Choose N to continue using the legacy 8254 timer.
772 config HPET_EMULATE_RTC
774 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
777 def_bool y if X86_INTEL_MID
778 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
780 depends on X86_INTEL_MID && SFI
782 APB timer is the replacement for 8254, HPET on X86 MID platforms.
783 The APBT provides a stable time base on SMP
784 systems, unlike the TSC, but it is more expensive to access,
785 as it is off-chip. APB timers are always running regardless of CPU
786 C states, they are used as per CPU clockevent device when possible.
788 # Mark as expert because too many people got it wrong.
789 # The code disables itself when not needed.
792 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
793 bool "Enable DMI scanning" if EXPERT
795 Enabled scanning of DMI to identify machine quirks. Say Y
796 here unless you have verified that your setup is not
797 affected by entries in the DMI blacklist. Required by PNP
801 bool "Old AMD GART IOMMU support"
803 depends on X86_64 && PCI && AMD_NB
805 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
806 GART based hardware IOMMUs.
808 The GART supports full DMA access for devices with 32-bit access
809 limitations, on systems with more than 3 GB. This is usually needed
810 for USB, sound, many IDE/SATA chipsets and some other devices.
812 Newer systems typically have a modern AMD IOMMU, supported via
813 the CONFIG_AMD_IOMMU=y config option.
815 In normal configurations this driver is only active when needed:
816 there's more than 3 GB of memory and the system contains a
817 32-bit limited device.
822 bool "IBM Calgary IOMMU support"
824 depends on X86_64 && PCI
826 Support for hardware IOMMUs in IBM's xSeries x366 and x460
827 systems. Needed to run systems with more than 3GB of memory
828 properly with 32-bit PCI devices that do not support DAC
829 (Double Address Cycle). Calgary also supports bus level
830 isolation, where all DMAs pass through the IOMMU. This
831 prevents them from going anywhere except their intended
832 destination. This catches hard-to-find kernel bugs and
833 mis-behaving drivers and devices that do not use the DMA-API
834 properly to set up their DMA buffers. The IOMMU can be
835 turned off at boot time with the iommu=off parameter.
836 Normally the kernel will make the right choice by itself.
839 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
841 prompt "Should Calgary be enabled by default?"
842 depends on CALGARY_IOMMU
844 Should Calgary be enabled by default? if you choose 'y', Calgary
845 will be used (if it exists). If you choose 'n', Calgary will not be
846 used even if it exists. If you choose 'n' and would like to use
847 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
850 # need this always selected by IOMMU for the VIA workaround
854 Support for software bounce buffers used on x86-64 systems
855 which don't have a hardware IOMMU. Using this PCI devices
856 which can only access 32-bits of memory can be used on systems
857 with more than 3 GB of memory.
862 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
865 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
866 depends on X86_64 && SMP && DEBUG_KERNEL
867 select CPUMASK_OFFSTACK
869 Enable maximum number of CPUS and NUMA Nodes for this architecture.
873 int "Maximum number of CPUs" if SMP && !MAXSMP
874 range 2 8 if SMP && X86_32 && !X86_BIGSMP
875 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
876 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
878 default "8192" if MAXSMP
879 default "32" if SMP && X86_BIGSMP
880 default "8" if SMP && X86_32
883 This allows you to specify the maximum number of CPUs which this
884 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
885 supported value is 8192, otherwise the maximum value is 512. The
886 minimum value which makes sense is 2.
888 This is purely to save memory - each supported CPU adds
889 approximately eight kilobytes to the kernel image.
892 bool "SMT (Hyperthreading) scheduler support"
895 SMT scheduler support improves the CPU scheduler's decision making
896 when dealing with Intel Pentium 4 chips with HyperThreading at a
897 cost of slightly increased overhead in some places. If unsure say
902 prompt "Multi-core scheduler support"
905 Multi-core scheduler support improves the CPU scheduler's decision
906 making when dealing with multi-core CPU chips at a cost of slightly
907 increased overhead in some places. If unsure say N here.
909 source "kernel/Kconfig.preempt"
913 depends on !SMP && X86_LOCAL_APIC
916 bool "Local APIC support on uniprocessors" if !PCI_MSI
918 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
920 A local APIC (Advanced Programmable Interrupt Controller) is an
921 integrated interrupt controller in the CPU. If you have a single-CPU
922 system which has a processor with a local APIC, you can say Y here to
923 enable and use it. If you say Y here even though your machine doesn't
924 have a local APIC, then the kernel will still run with no slowdown at
925 all. The local APIC supports CPU-generated self-interrupts (timer,
926 performance counters), and the NMI watchdog which detects hard
930 bool "IO-APIC support on uniprocessors"
931 depends on X86_UP_APIC
933 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
934 SMP-capable replacement for PC-style interrupt controllers. Most
935 SMP systems and many recent uniprocessor systems have one.
937 If you have a single-CPU system with an IO-APIC, you can say Y here
938 to use it. If you say Y here even though your machine doesn't have
939 an IO-APIC, then the kernel will still run with no slowdown at all.
941 config X86_LOCAL_APIC
943 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
944 select IRQ_DOMAIN_HIERARCHY
945 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
949 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
951 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
952 bool "Reroute for broken boot IRQs"
953 depends on X86_IO_APIC
955 This option enables a workaround that fixes a source of
956 spurious interrupts. This is recommended when threaded
957 interrupt handling is used on systems where the generation of
958 superfluous "boot interrupts" cannot be disabled.
960 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
961 entry in the chipset's IO-APIC is masked (as, e.g. the RT
962 kernel does during interrupt handling). On chipsets where this
963 boot IRQ generation cannot be disabled, this workaround keeps
964 the original IRQ line masked so that only the equivalent "boot
965 IRQ" is delivered to the CPUs. The workaround also tells the
966 kernel to set up the IRQ handler on the boot IRQ line. In this
967 way only one interrupt is delivered to the kernel. Otherwise
968 the spurious second interrupt may cause the kernel to bring
969 down (vital) interrupt lines.
971 Only affects "broken" chipsets. Interrupt sharing may be
972 increased on these systems.
975 bool "Machine Check / overheating reporting"
976 select GENERIC_ALLOCATOR
979 Machine Check support allows the processor to notify the
980 kernel if it detects a problem (e.g. overheating, data corruption).
981 The action the kernel takes depends on the severity of the problem,
982 ranging from warning messages to halting the machine.
986 prompt "Intel MCE features"
987 depends on X86_MCE && X86_LOCAL_APIC
989 Additional support for intel specific MCE features such as
994 prompt "AMD MCE features"
995 depends on X86_MCE && X86_LOCAL_APIC
997 Additional support for AMD specific MCE features such as
998 the DRAM Error Threshold.
1000 config X86_ANCIENT_MCE
1001 bool "Support for old Pentium 5 / WinChip machine checks"
1002 depends on X86_32 && X86_MCE
1004 Include support for machine check handling on old Pentium 5 or WinChip
1005 systems. These typically need to be enabled explicitly on the command
1008 config X86_MCE_THRESHOLD
1009 depends on X86_MCE_AMD || X86_MCE_INTEL
1012 config X86_MCE_INJECT
1014 tristate "Machine check injector support"
1016 Provide support for injecting machine checks for testing purposes.
1017 If you don't know what a machine check is and you don't do kernel
1018 QA it is safe to say n.
1020 config X86_THERMAL_VECTOR
1022 depends on X86_MCE_INTEL
1024 config X86_LEGACY_VM86
1025 bool "Legacy VM86 support"
1029 This option allows user programs to put the CPU into V8086
1030 mode, which is an 80286-era approximation of 16-bit real mode.
1032 Some very old versions of X and/or vbetool require this option
1033 for user mode setting. Similarly, DOSEMU will use it if
1034 available to accelerate real mode DOS programs. However, any
1035 recent version of DOSEMU, X, or vbetool should be fully
1036 functional even without kernel VM86 support, as they will all
1037 fall back to software emulation. Nevertheless, if you are using
1038 a 16-bit DOS program where 16-bit performance matters, vm86
1039 mode might be faster than emulation and you might want to
1042 Note that any app that works on a 64-bit kernel is unlikely to
1043 need this option, as 64-bit kernels don't, and can't, support
1044 V8086 mode. This option is also unrelated to 16-bit protected
1045 mode and is not needed to run most 16-bit programs under Wine.
1047 Enabling this option increases the complexity of the kernel
1048 and slows down exception handling a tiny bit.
1050 If unsure, say N here.
1054 default X86_LEGACY_VM86
1057 bool "Enable support for 16-bit segments" if EXPERT
1059 depends on MODIFY_LDT_SYSCALL
1061 This option is required by programs like Wine to run 16-bit
1062 protected mode legacy code on x86 processors. Disabling
1063 this option saves about 300 bytes on i386, or around 6K text
1064 plus 16K runtime memory on x86-64,
1068 depends on X86_16BIT && X86_32
1072 depends on X86_16BIT && X86_64
1074 config X86_VSYSCALL_EMULATION
1075 bool "Enable vsyscall emulation" if EXPERT
1079 This enables emulation of the legacy vsyscall page. Disabling
1080 it is roughly equivalent to booting with vsyscall=none, except
1081 that it will also disable the helpful warning if a program
1082 tries to use a vsyscall. With this option set to N, offending
1083 programs will just segfault, citing addresses of the form
1086 This option is required by many programs built before 2013, and
1087 care should be used even with newer programs if set to N.
1089 Disabling this option saves about 7K of kernel size and
1090 possibly 4K of additional runtime pagetable memory.
1093 tristate "Toshiba Laptop support"
1096 This adds a driver to safely access the System Management Mode of
1097 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1098 not work on models with a Phoenix BIOS. The System Management Mode
1099 is used to set the BIOS and power saving options on Toshiba portables.
1101 For information on utilities to make use of this driver see the
1102 Toshiba Linux utilities web site at:
1103 <http://www.buzzard.org.uk/toshiba/>.
1105 Say Y if you intend to run this kernel on a Toshiba portable.
1109 tristate "Dell i8k legacy laptop support"
1111 select SENSORS_DELL_SMM
1113 This option enables legacy /proc/i8k userspace interface in hwmon
1114 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1115 temperature and allows controlling fan speeds of Dell laptops via
1116 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1117 it reports also power and hotkey status. For fan speed control is
1118 needed userspace package i8kutils.
1120 Say Y if you intend to run this kernel on old Dell laptops or want to
1121 use userspace package i8kutils.
1124 config X86_REBOOTFIXUPS
1125 bool "Enable X86 board specific fixups for reboot"
1128 This enables chipset and/or board specific fixups to be done
1129 in order to get reboot to work correctly. This is only needed on
1130 some combinations of hardware and BIOS. The symptom, for which
1131 this config is intended, is when reboot ends with a stalled/hung
1134 Currently, the only fixup is for the Geode machines using
1135 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1137 Say Y if you want to enable the fixup. Currently, it's safe to
1138 enable this option even if you don't need it.
1142 bool "CPU microcode loading support"
1144 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1145 depends on BLK_DEV_INITRD
1149 If you say Y here, you will be able to update the microcode on
1150 certain Intel and AMD processors. The Intel support is for the
1151 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1152 Xeon etc. The AMD support is for families 0x10 and later. You will
1153 obviously need the actual microcode binary data itself which is not
1154 shipped with the Linux kernel.
1156 This option selects the general module only, you need to select
1157 at least one vendor specific module as well.
1159 To compile this driver as a module, choose M here: the module
1160 will be called microcode.
1162 config MICROCODE_INTEL
1163 bool "Intel microcode loading support"
1164 depends on MICROCODE
1168 This options enables microcode patch loading support for Intel
1171 For the current Intel microcode data package go to
1172 <https://downloadcenter.intel.com> and search for
1173 'Linux Processor Microcode Data File'.
1175 config MICROCODE_AMD
1176 bool "AMD microcode loading support"
1177 depends on MICROCODE
1180 If you select this option, microcode patch loading support for AMD
1181 processors will be enabled.
1183 config MICROCODE_OLD_INTERFACE
1185 depends on MICROCODE
1188 tristate "/dev/cpu/*/msr - Model-specific register support"
1190 This device gives privileged processes access to the x86
1191 Model-Specific Registers (MSRs). It is a character device with
1192 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1193 MSR accesses are directed to a specific CPU on multi-processor
1197 tristate "/dev/cpu/*/cpuid - CPU information support"
1199 This device gives processes access to the x86 CPUID instruction to
1200 be executed on a specific processor. It is a character device
1201 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1205 prompt "High Memory Support"
1212 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1213 However, the address space of 32-bit x86 processors is only 4
1214 Gigabytes large. That means that, if you have a large amount of
1215 physical memory, not all of it can be "permanently mapped" by the
1216 kernel. The physical memory that's not permanently mapped is called
1219 If you are compiling a kernel which will never run on a machine with
1220 more than 1 Gigabyte total physical RAM, answer "off" here (default
1221 choice and suitable for most users). This will result in a "3GB/1GB"
1222 split: 3GB are mapped so that each process sees a 3GB virtual memory
1223 space and the remaining part of the 4GB virtual memory space is used
1224 by the kernel to permanently map as much physical memory as
1227 If the machine has between 1 and 4 Gigabytes physical RAM, then
1230 If more than 4 Gigabytes is used then answer "64GB" here. This
1231 selection turns Intel PAE (Physical Address Extension) mode on.
1232 PAE implements 3-level paging on IA32 processors. PAE is fully
1233 supported by Linux, PAE mode is implemented on all recent Intel
1234 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1235 then the kernel will not boot on CPUs that don't support PAE!
1237 The actual amount of total physical memory will either be
1238 auto detected or can be forced by using a kernel command line option
1239 such as "mem=256M". (Try "man bootparam" or see the documentation of
1240 your boot loader (lilo or loadlin) about how to pass options to the
1241 kernel at boot time.)
1243 If unsure, say "off".
1248 Select this if you have a 32-bit processor and between 1 and 4
1249 gigabytes of physical RAM.
1256 Select this if you have a 32-bit processor and more than 4
1257 gigabytes of physical RAM.
1262 prompt "Memory split" if EXPERT
1266 Select the desired split between kernel and user memory.
1268 If the address range available to the kernel is less than the
1269 physical memory installed, the remaining memory will be available
1270 as "high memory". Accessing high memory is a little more costly
1271 than low memory, as it needs to be mapped into the kernel first.
1272 Note that increasing the kernel address space limits the range
1273 available to user programs, making the address space there
1274 tighter. Selecting anything other than the default 3G/1G split
1275 will also likely make your kernel incompatible with binary-only
1278 If you are not absolutely sure what you are doing, leave this
1282 bool "3G/1G user/kernel split"
1283 config VMSPLIT_3G_OPT
1285 bool "3G/1G user/kernel split (for full 1G low memory)"
1287 bool "2G/2G user/kernel split"
1288 config VMSPLIT_2G_OPT
1290 bool "2G/2G user/kernel split (for full 2G low memory)"
1292 bool "1G/3G user/kernel split"
1297 default 0xB0000000 if VMSPLIT_3G_OPT
1298 default 0x80000000 if VMSPLIT_2G
1299 default 0x78000000 if VMSPLIT_2G_OPT
1300 default 0x40000000 if VMSPLIT_1G
1306 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1309 bool "PAE (Physical Address Extension) Support"
1310 depends on X86_32 && !HIGHMEM4G
1313 PAE is required for NX support, and furthermore enables
1314 larger swapspace support for non-overcommit purposes. It
1315 has the cost of more pagetable lookup overhead, and also
1316 consumes more pagetable space per process.
1318 config ARCH_PHYS_ADDR_T_64BIT
1320 depends on X86_64 || X86_PAE
1322 config ARCH_DMA_ADDR_T_64BIT
1324 depends on X86_64 || HIGHMEM64G
1326 config X86_DIRECT_GBPAGES
1328 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1330 Certain kernel features effectively disable kernel
1331 linear 1 GB mappings (even if the CPU otherwise
1332 supports them), so don't confuse the user by printing
1333 that we have them enabled.
1335 # Common NUMA Features
1337 bool "Numa Memory Allocation and Scheduler Support"
1339 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1340 default y if X86_BIGSMP
1342 Enable NUMA (Non Uniform Memory Access) support.
1344 The kernel will try to allocate memory used by a CPU on the
1345 local memory controller of the CPU and add some more
1346 NUMA awareness to the kernel.
1348 For 64-bit this is recommended if the system is Intel Core i7
1349 (or later), AMD Opteron, or EM64T NUMA.
1351 For 32-bit this is only needed if you boot a 32-bit
1352 kernel on a 64-bit NUMA platform.
1354 Otherwise, you should say N.
1358 prompt "Old style AMD Opteron NUMA detection"
1359 depends on X86_64 && NUMA && PCI
1361 Enable AMD NUMA node topology detection. You should say Y here if
1362 you have a multi processor AMD system. This uses an old method to
1363 read the NUMA configuration directly from the builtin Northbridge
1364 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1365 which also takes priority if both are compiled in.
1367 config X86_64_ACPI_NUMA
1369 prompt "ACPI NUMA detection"
1370 depends on X86_64 && NUMA && ACPI && PCI
1373 Enable ACPI SRAT based node topology detection.
1375 # Some NUMA nodes have memory ranges that span
1376 # other nodes. Even though a pfn is valid and
1377 # between a node's start and end pfns, it may not
1378 # reside on that node. See memmap_init_zone()
1380 config NODES_SPAN_OTHER_NODES
1382 depends on X86_64_ACPI_NUMA
1385 bool "NUMA emulation"
1388 Enable NUMA emulation. A flat machine will be split
1389 into virtual nodes when booted with "numa=fake=N", where N is the
1390 number of nodes. This is only useful for debugging.
1393 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1395 default "10" if MAXSMP
1396 default "6" if X86_64
1398 depends on NEED_MULTIPLE_NODES
1400 Specify the maximum number of NUMA Nodes available on the target
1401 system. Increases memory reserved to accommodate various tables.
1403 config ARCH_HAVE_MEMORY_PRESENT
1405 depends on X86_32 && DISCONTIGMEM
1407 config NEED_NODE_MEMMAP_SIZE
1409 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1411 config ARCH_FLATMEM_ENABLE
1413 depends on X86_32 && !NUMA
1415 config ARCH_DISCONTIGMEM_ENABLE
1417 depends on NUMA && X86_32
1419 config ARCH_DISCONTIGMEM_DEFAULT
1421 depends on NUMA && X86_32
1423 config ARCH_SPARSEMEM_ENABLE
1425 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1426 select SPARSEMEM_STATIC if X86_32
1427 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1429 config ARCH_SPARSEMEM_DEFAULT
1433 config ARCH_SELECT_MEMORY_MODEL
1435 depends on ARCH_SPARSEMEM_ENABLE
1437 config ARCH_MEMORY_PROBE
1438 bool "Enable sysfs memory/probe interface"
1439 depends on X86_64 && MEMORY_HOTPLUG
1441 This option enables a sysfs memory/probe interface for testing.
1442 See Documentation/memory-hotplug.txt for more information.
1443 If you are unsure how to answer this question, answer N.
1445 config ARCH_PROC_KCORE_TEXT
1447 depends on X86_64 && PROC_KCORE
1449 config ILLEGAL_POINTER_VALUE
1452 default 0xdead000000000000 if X86_64
1456 config X86_PMEM_LEGACY_DEVICE
1459 config X86_PMEM_LEGACY
1460 tristate "Support non-standard NVDIMMs and ADR protected memory"
1461 depends on PHYS_ADDR_T_64BIT
1463 select X86_PMEM_LEGACY_DEVICE
1466 Treat memory marked using the non-standard e820 type of 12 as used
1467 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1468 The kernel will offer these regions to the 'pmem' driver so
1469 they can be used for persistent storage.
1474 bool "Allocate 3rd-level pagetables from highmem"
1477 The VM uses one page table entry for each page of physical memory.
1478 For systems with a lot of RAM, this can be wasteful of precious
1479 low memory. Setting this option will put user-space page table
1480 entries in high memory.
1482 config X86_CHECK_BIOS_CORRUPTION
1483 bool "Check for low memory corruption"
1485 Periodically check for memory corruption in low memory, which
1486 is suspected to be caused by BIOS. Even when enabled in the
1487 configuration, it is disabled at runtime. Enable it by
1488 setting "memory_corruption_check=1" on the kernel command
1489 line. By default it scans the low 64k of memory every 60
1490 seconds; see the memory_corruption_check_size and
1491 memory_corruption_check_period parameters in
1492 Documentation/kernel-parameters.txt to adjust this.
1494 When enabled with the default parameters, this option has
1495 almost no overhead, as it reserves a relatively small amount
1496 of memory and scans it infrequently. It both detects corruption
1497 and prevents it from affecting the running system.
1499 It is, however, intended as a diagnostic tool; if repeatable
1500 BIOS-originated corruption always affects the same memory,
1501 you can use memmap= to prevent the kernel from using that
1504 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1505 bool "Set the default setting of memory_corruption_check"
1506 depends on X86_CHECK_BIOS_CORRUPTION
1509 Set whether the default state of memory_corruption_check is
1512 config X86_RESERVE_LOW
1513 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1517 Specify the amount of low memory to reserve for the BIOS.
1519 The first page contains BIOS data structures that the kernel
1520 must not use, so that page must always be reserved.
1522 By default we reserve the first 64K of physical RAM, as a
1523 number of BIOSes are known to corrupt that memory range
1524 during events such as suspend/resume or monitor cable
1525 insertion, so it must not be used by the kernel.
1527 You can set this to 4 if you are absolutely sure that you
1528 trust the BIOS to get all its memory reservations and usages
1529 right. If you know your BIOS have problems beyond the
1530 default 64K area, you can set this to 640 to avoid using the
1531 entire low memory range.
1533 If you have doubts about the BIOS (e.g. suspend/resume does
1534 not work or there's kernel crashes after certain hardware
1535 hotplug events) then you might want to enable
1536 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1537 typical corruption patterns.
1539 Leave this to the default value of 64 if you are unsure.
1541 config MATH_EMULATION
1543 depends on MODIFY_LDT_SYSCALL
1544 prompt "Math emulation" if X86_32
1546 Linux can emulate a math coprocessor (used for floating point
1547 operations) if you don't have one. 486DX and Pentium processors have
1548 a math coprocessor built in, 486SX and 386 do not, unless you added
1549 a 487DX or 387, respectively. (The messages during boot time can
1550 give you some hints here ["man dmesg"].) Everyone needs either a
1551 coprocessor or this emulation.
1553 If you don't have a math coprocessor, you need to say Y here; if you
1554 say Y here even though you have a coprocessor, the coprocessor will
1555 be used nevertheless. (This behavior can be changed with the kernel
1556 command line option "no387", which comes handy if your coprocessor
1557 is broken. Try "man bootparam" or see the documentation of your boot
1558 loader (lilo or loadlin) about how to pass options to the kernel at
1559 boot time.) This means that it is a good idea to say Y here if you
1560 intend to use this kernel on different machines.
1562 More information about the internals of the Linux math coprocessor
1563 emulation can be found in <file:arch/x86/math-emu/README>.
1565 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1566 kernel, it won't hurt.
1570 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1572 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1573 the Memory Type Range Registers (MTRRs) may be used to control
1574 processor access to memory ranges. This is most useful if you have
1575 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1576 allows bus write transfers to be combined into a larger transfer
1577 before bursting over the PCI/AGP bus. This can increase performance
1578 of image write operations 2.5 times or more. Saying Y here creates a
1579 /proc/mtrr file which may be used to manipulate your processor's
1580 MTRRs. Typically the X server should use this.
1582 This code has a reasonably generic interface so that similar
1583 control registers on other processors can be easily supported
1586 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1587 Registers (ARRs) which provide a similar functionality to MTRRs. For
1588 these, the ARRs are used to emulate the MTRRs.
1589 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1590 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1591 write-combining. All of these processors are supported by this code
1592 and it makes sense to say Y here if you have one of them.
1594 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1595 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1596 can lead to all sorts of problems, so it's good to say Y here.
1598 You can safely say Y even if your machine doesn't have MTRRs, you'll
1599 just add about 9 KB to your kernel.
1601 See <file:Documentation/x86/mtrr.txt> for more information.
1603 config MTRR_SANITIZER
1605 prompt "MTRR cleanup support"
1608 Convert MTRR layout from continuous to discrete, so X drivers can
1609 add writeback entries.
1611 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1612 The largest mtrr entry size for a continuous block can be set with
1617 config MTRR_SANITIZER_ENABLE_DEFAULT
1618 int "MTRR cleanup enable value (0-1)"
1621 depends on MTRR_SANITIZER
1623 Enable mtrr cleanup default value
1625 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1626 int "MTRR cleanup spare reg num (0-7)"
1629 depends on MTRR_SANITIZER
1631 mtrr cleanup spare entries default, it can be changed via
1632 mtrr_spare_reg_nr=N on the kernel command line.
1636 prompt "x86 PAT support" if EXPERT
1639 Use PAT attributes to setup page level cache control.
1641 PATs are the modern equivalents of MTRRs and are much more
1642 flexible than MTRRs.
1644 Say N here if you see bootup problems (boot crash, boot hang,
1645 spontaneous reboots) or a non-working video driver.
1649 config ARCH_USES_PG_UNCACHED
1655 prompt "x86 architectural random number generator" if EXPERT
1657 Enable the x86 architectural RDRAND instruction
1658 (Intel Bull Mountain technology) to generate random numbers.
1659 If supported, this is a high bandwidth, cryptographically
1660 secure hardware random number generator.
1664 prompt "Supervisor Mode Access Prevention" if EXPERT
1666 Supervisor Mode Access Prevention (SMAP) is a security
1667 feature in newer Intel processors. There is a small
1668 performance cost if this enabled and turned on; there is
1669 also a small increase in the kernel size if this is enabled.
1673 config X86_INTEL_MPX
1674 prompt "Intel MPX (Memory Protection Extensions)"
1676 depends on CPU_SUP_INTEL
1678 MPX provides hardware features that can be used in
1679 conjunction with compiler-instrumented code to check
1680 memory references. It is designed to detect buffer
1681 overflow or underflow bugs.
1683 This option enables running applications which are
1684 instrumented or otherwise use MPX. It does not use MPX
1685 itself inside the kernel or to protect the kernel
1686 against bad memory references.
1688 Enabling this option will make the kernel larger:
1689 ~8k of kernel text and 36 bytes of data on a 64-bit
1690 defconfig. It adds a long to the 'mm_struct' which
1691 will increase the kernel memory overhead of each
1692 process and adds some branches to paths used during
1693 exec() and munmap().
1695 For details, see Documentation/x86/intel_mpx.txt
1700 bool "EFI runtime service support"
1703 select EFI_RUNTIME_WRAPPERS
1705 This enables the kernel to use EFI runtime services that are
1706 available (such as the EFI variable services).
1708 This option is only useful on systems that have EFI firmware.
1709 In addition, you should use the latest ELILO loader available
1710 at <http://elilo.sourceforge.net> in order to take advantage
1711 of EFI runtime services. However, even with this option, the
1712 resultant kernel should continue to boot on existing non-EFI
1716 bool "EFI stub support"
1717 depends on EFI && !X86_USE_3DNOW
1720 This kernel feature allows a bzImage to be loaded directly
1721 by EFI firmware without the use of a bootloader.
1723 See Documentation/efi-stub.txt for more information.
1726 bool "EFI mixed-mode support"
1727 depends on EFI_STUB && X86_64
1729 Enabling this feature allows a 64-bit kernel to be booted
1730 on a 32-bit firmware, provided that your CPU supports 64-bit
1733 Note that it is not possible to boot a mixed-mode enabled
1734 kernel via the EFI boot stub - a bootloader that supports
1735 the EFI handover protocol must be used.
1741 prompt "Enable seccomp to safely compute untrusted bytecode"
1743 This kernel feature is useful for number crunching applications
1744 that may need to compute untrusted bytecode during their
1745 execution. By using pipes or other transports made available to
1746 the process as file descriptors supporting the read/write
1747 syscalls, it's possible to isolate those applications in
1748 their own address space using seccomp. Once seccomp is
1749 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1750 and the task is only allowed to execute a few safe syscalls
1751 defined by each seccomp mode.
1753 If unsure, say Y. Only embedded should say N here.
1755 source kernel/Kconfig.hz
1758 bool "kexec system call"
1761 kexec is a system call that implements the ability to shutdown your
1762 current kernel, and to start another kernel. It is like a reboot
1763 but it is independent of the system firmware. And like a reboot
1764 you can start any kernel with it, not just Linux.
1766 The name comes from the similarity to the exec system call.
1768 It is an ongoing process to be certain the hardware in a machine
1769 is properly shutdown, so do not be surprised if this code does not
1770 initially work for you. As of this writing the exact hardware
1771 interface is strongly in flux, so no good recommendation can be
1775 bool "kexec file based system call"
1780 depends on CRYPTO_SHA256=y
1782 This is new version of kexec system call. This system call is
1783 file based and takes file descriptors as system call argument
1784 for kernel and initramfs as opposed to list of segments as
1785 accepted by previous system call.
1787 config KEXEC_VERIFY_SIG
1788 bool "Verify kernel signature during kexec_file_load() syscall"
1789 depends on KEXEC_FILE
1791 This option makes kernel signature verification mandatory for
1792 the kexec_file_load() syscall.
1794 In addition to that option, you need to enable signature
1795 verification for the corresponding kernel image type being
1796 loaded in order for this to work.
1798 config KEXEC_BZIMAGE_VERIFY_SIG
1799 bool "Enable bzImage signature verification support"
1800 depends on KEXEC_VERIFY_SIG
1801 depends on SIGNED_PE_FILE_VERIFICATION
1802 select SYSTEM_TRUSTED_KEYRING
1804 Enable bzImage signature verification support.
1807 bool "kernel crash dumps"
1808 depends on X86_64 || (X86_32 && HIGHMEM)
1810 Generate crash dump after being started by kexec.
1811 This should be normally only set in special crash dump kernels
1812 which are loaded in the main kernel with kexec-tools into
1813 a specially reserved region and then later executed after
1814 a crash by kdump/kexec. The crash dump kernel must be compiled
1815 to a memory address not used by the main kernel or BIOS using
1816 PHYSICAL_START, or it must be built as a relocatable image
1817 (CONFIG_RELOCATABLE=y).
1818 For more details see Documentation/kdump/kdump.txt
1822 depends on KEXEC && HIBERNATION
1824 Jump between original kernel and kexeced kernel and invoke
1825 code in physical address mode via KEXEC
1827 config PHYSICAL_START
1828 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1831 This gives the physical address where the kernel is loaded.
1833 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1834 bzImage will decompress itself to above physical address and
1835 run from there. Otherwise, bzImage will run from the address where
1836 it has been loaded by the boot loader and will ignore above physical
1839 In normal kdump cases one does not have to set/change this option
1840 as now bzImage can be compiled as a completely relocatable image
1841 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1842 address. This option is mainly useful for the folks who don't want
1843 to use a bzImage for capturing the crash dump and want to use a
1844 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1845 to be specifically compiled to run from a specific memory area
1846 (normally a reserved region) and this option comes handy.
1848 So if you are using bzImage for capturing the crash dump,
1849 leave the value here unchanged to 0x1000000 and set
1850 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1851 for capturing the crash dump change this value to start of
1852 the reserved region. In other words, it can be set based on
1853 the "X" value as specified in the "crashkernel=YM@XM"
1854 command line boot parameter passed to the panic-ed
1855 kernel. Please take a look at Documentation/kdump/kdump.txt
1856 for more details about crash dumps.
1858 Usage of bzImage for capturing the crash dump is recommended as
1859 one does not have to build two kernels. Same kernel can be used
1860 as production kernel and capture kernel. Above option should have
1861 gone away after relocatable bzImage support is introduced. But it
1862 is present because there are users out there who continue to use
1863 vmlinux for dump capture. This option should go away down the
1866 Don't change this unless you know what you are doing.
1869 bool "Build a relocatable kernel"
1872 This builds a kernel image that retains relocation information
1873 so it can be loaded someplace besides the default 1MB.
1874 The relocations tend to make the kernel binary about 10% larger,
1875 but are discarded at runtime.
1877 One use is for the kexec on panic case where the recovery kernel
1878 must live at a different physical address than the primary
1881 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1882 it has been loaded at and the compile time physical address
1883 (CONFIG_PHYSICAL_START) is used as the minimum location.
1885 config RANDOMIZE_BASE
1886 bool "Randomize the address of the kernel image"
1887 depends on RELOCATABLE
1890 Randomizes the physical and virtual address at which the
1891 kernel image is decompressed, as a security feature that
1892 deters exploit attempts relying on knowledge of the location
1893 of kernel internals.
1895 Entropy is generated using the RDRAND instruction if it is
1896 supported. If RDTSC is supported, it is used as well. If
1897 neither RDRAND nor RDTSC are supported, then randomness is
1898 read from the i8254 timer.
1900 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1901 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1902 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1903 minimum of 2MiB, only 10 bits of entropy is theoretically
1904 possible. At best, due to page table layouts, 64-bit can use
1905 9 bits of entropy and 32-bit uses 8 bits.
1909 config RANDOMIZE_BASE_MAX_OFFSET
1910 hex "Maximum kASLR offset allowed" if EXPERT
1911 depends on RANDOMIZE_BASE
1912 range 0x0 0x20000000 if X86_32
1913 default "0x20000000" if X86_32
1914 range 0x0 0x40000000 if X86_64
1915 default "0x40000000" if X86_64
1917 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1918 memory is used to determine the maximal offset in bytes that will
1919 be applied to the kernel when kernel Address Space Layout
1920 Randomization (kASLR) is active. This must be a multiple of
1923 On 32-bit this is limited to 512MiB by page table layouts. The
1926 On 64-bit this is limited by how the kernel fixmap page table is
1927 positioned, so this cannot be larger than 1GiB currently. Without
1928 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1929 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1930 modules area will shrink to compensate, up to the current maximum
1931 1GiB to 1GiB split. The default is 1GiB.
1933 If unsure, leave at the default value.
1935 # Relocation on x86 needs some additional build support
1936 config X86_NEED_RELOCS
1938 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1940 config PHYSICAL_ALIGN
1941 hex "Alignment value to which kernel should be aligned"
1943 range 0x2000 0x1000000 if X86_32
1944 range 0x200000 0x1000000 if X86_64
1946 This value puts the alignment restrictions on physical address
1947 where kernel is loaded and run from. Kernel is compiled for an
1948 address which meets above alignment restriction.
1950 If bootloader loads the kernel at a non-aligned address and
1951 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1952 address aligned to above value and run from there.
1954 If bootloader loads the kernel at a non-aligned address and
1955 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1956 load address and decompress itself to the address it has been
1957 compiled for and run from there. The address for which kernel is
1958 compiled already meets above alignment restrictions. Hence the
1959 end result is that kernel runs from a physical address meeting
1960 above alignment restrictions.
1962 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1963 this value must be a multiple of 0x200000.
1965 Don't change this unless you know what you are doing.
1968 bool "Support for hot-pluggable CPUs"
1971 Say Y here to allow turning CPUs off and on. CPUs can be
1972 controlled through /sys/devices/system/cpu.
1973 ( Note: power management support will enable this option
1974 automatically on SMP systems. )
1975 Say N if you want to disable CPU hotplug.
1977 config BOOTPARAM_HOTPLUG_CPU0
1978 bool "Set default setting of cpu0_hotpluggable"
1980 depends on HOTPLUG_CPU
1982 Set whether default state of cpu0_hotpluggable is on or off.
1984 Say Y here to enable CPU0 hotplug by default. If this switch
1985 is turned on, there is no need to give cpu0_hotplug kernel
1986 parameter and the CPU0 hotplug feature is enabled by default.
1988 Please note: there are two known CPU0 dependencies if you want
1989 to enable the CPU0 hotplug feature either by this switch or by
1990 cpu0_hotplug kernel parameter.
1992 First, resume from hibernate or suspend always starts from CPU0.
1993 So hibernate and suspend are prevented if CPU0 is offline.
1995 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1996 offline if any interrupt can not migrate out of CPU0. There may
1997 be other CPU0 dependencies.
1999 Please make sure the dependencies are under your control before
2000 you enable this feature.
2002 Say N if you don't want to enable CPU0 hotplug feature by default.
2003 You still can enable the CPU0 hotplug feature at boot by kernel
2004 parameter cpu0_hotplug.
2006 config DEBUG_HOTPLUG_CPU0
2008 prompt "Debug CPU0 hotplug"
2009 depends on HOTPLUG_CPU
2011 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2012 soon as possible and boots up userspace with CPU0 offlined. User
2013 can online CPU0 back after boot time.
2015 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2016 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2017 compilation or giving cpu0_hotplug kernel parameter at boot.
2023 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2024 depends on X86_32 || IA32_EMULATION
2026 Certain buggy versions of glibc will crash if they are
2027 presented with a 32-bit vDSO that is not mapped at the address
2028 indicated in its segment table.
2030 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2031 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2032 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2033 the only released version with the bug, but OpenSUSE 9
2034 contains a buggy "glibc 2.3.2".
2036 The symptom of the bug is that everything crashes on startup, saying:
2037 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2039 Saying Y here changes the default value of the vdso32 boot
2040 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2041 This works around the glibc bug but hurts performance.
2043 If unsure, say N: if you are compiling your own kernel, you
2044 are unlikely to be using a buggy version of glibc.
2047 prompt "vsyscall table for legacy applications"
2049 default LEGACY_VSYSCALL_EMULATE
2051 Legacy user code that does not know how to find the vDSO expects
2052 to be able to issue three syscalls by calling fixed addresses in
2053 kernel space. Since this location is not randomized with ASLR,
2054 it can be used to assist security vulnerability exploitation.
2056 This setting can be changed at boot time via the kernel command
2057 line parameter vsyscall=[native|emulate|none].
2059 On a system with recent enough glibc (2.14 or newer) and no
2060 static binaries, you can say None without a performance penalty
2061 to improve security.
2063 If unsure, select "Emulate".
2065 config LEGACY_VSYSCALL_NATIVE
2068 Actual executable code is located in the fixed vsyscall
2069 address mapping, implementing time() efficiently. Since
2070 this makes the mapping executable, it can be used during
2071 security vulnerability exploitation (traditionally as
2072 ROP gadgets). This configuration is not recommended.
2074 config LEGACY_VSYSCALL_EMULATE
2077 The kernel traps and emulates calls into the fixed
2078 vsyscall address mapping. This makes the mapping
2079 non-executable, but it still contains known contents,
2080 which could be used in certain rare security vulnerability
2081 exploits. This configuration is recommended when userspace
2082 still uses the vsyscall area.
2084 config LEGACY_VSYSCALL_NONE
2087 There will be no vsyscall mapping at all. This will
2088 eliminate any risk of ASLR bypass due to the vsyscall
2089 fixed address mapping. Attempts to use the vsyscalls
2090 will be reported to dmesg, so that either old or
2091 malicious userspace programs can be identified.
2096 bool "Built-in kernel command line"
2098 Allow for specifying boot arguments to the kernel at
2099 build time. On some systems (e.g. embedded ones), it is
2100 necessary or convenient to provide some or all of the
2101 kernel boot arguments with the kernel itself (that is,
2102 to not rely on the boot loader to provide them.)
2104 To compile command line arguments into the kernel,
2105 set this option to 'Y', then fill in the
2106 boot arguments in CONFIG_CMDLINE.
2108 Systems with fully functional boot loaders (i.e. non-embedded)
2109 should leave this option set to 'N'.
2112 string "Built-in kernel command string"
2113 depends on CMDLINE_BOOL
2116 Enter arguments here that should be compiled into the kernel
2117 image and used at boot time. If the boot loader provides a
2118 command line at boot time, it is appended to this string to
2119 form the full kernel command line, when the system boots.
2121 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2122 change this behavior.
2124 In most cases, the command line (whether built-in or provided
2125 by the boot loader) should specify the device for the root
2128 config CMDLINE_OVERRIDE
2129 bool "Built-in command line overrides boot loader arguments"
2130 depends on CMDLINE_BOOL
2132 Set this option to 'Y' to have the kernel ignore the boot loader
2133 command line, and use ONLY the built-in command line.
2135 This is used to work around broken boot loaders. This should
2136 be set to 'N' under normal conditions.
2138 config MODIFY_LDT_SYSCALL
2139 bool "Enable the LDT (local descriptor table)" if EXPERT
2142 Linux can allow user programs to install a per-process x86
2143 Local Descriptor Table (LDT) using the modify_ldt(2) system
2144 call. This is required to run 16-bit or segmented code such as
2145 DOSEMU or some Wine programs. It is also used by some very old
2146 threading libraries.
2148 Enabling this feature adds a small amount of overhead to
2149 context switches and increases the low-level kernel attack
2150 surface. Disabling it removes the modify_ldt(2) system call.
2152 Saying 'N' here may make sense for embedded or server kernels.
2154 source "kernel/livepatch/Kconfig"
2158 config ARCH_ENABLE_MEMORY_HOTPLUG
2160 depends on X86_64 || (X86_32 && HIGHMEM)
2162 config ARCH_ENABLE_MEMORY_HOTREMOVE
2164 depends on MEMORY_HOTPLUG
2166 config USE_PERCPU_NUMA_NODE_ID
2170 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2172 depends on X86_64 || X86_PAE
2174 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2176 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2178 menu "Power management and ACPI options"
2180 config ARCH_HIBERNATION_HEADER
2182 depends on X86_64 && HIBERNATION
2184 source "kernel/power/Kconfig"
2186 source "drivers/acpi/Kconfig"
2188 source "drivers/sfi/Kconfig"
2195 tristate "APM (Advanced Power Management) BIOS support"
2196 depends on X86_32 && PM_SLEEP
2198 APM is a BIOS specification for saving power using several different
2199 techniques. This is mostly useful for battery powered laptops with
2200 APM compliant BIOSes. If you say Y here, the system time will be
2201 reset after a RESUME operation, the /proc/apm device will provide
2202 battery status information, and user-space programs will receive
2203 notification of APM "events" (e.g. battery status change).
2205 If you select "Y" here, you can disable actual use of the APM
2206 BIOS by passing the "apm=off" option to the kernel at boot time.
2208 Note that the APM support is almost completely disabled for
2209 machines with more than one CPU.
2211 In order to use APM, you will need supporting software. For location
2212 and more information, read <file:Documentation/power/apm-acpi.txt>
2213 and the Battery Powered Linux mini-HOWTO, available from
2214 <http://www.tldp.org/docs.html#howto>.
2216 This driver does not spin down disk drives (see the hdparm(8)
2217 manpage ("man 8 hdparm") for that), and it doesn't turn off
2218 VESA-compliant "green" monitors.
2220 This driver does not support the TI 4000M TravelMate and the ACER
2221 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2222 desktop machines also don't have compliant BIOSes, and this driver
2223 may cause those machines to panic during the boot phase.
2225 Generally, if you don't have a battery in your machine, there isn't
2226 much point in using this driver and you should say N. If you get
2227 random kernel OOPSes or reboots that don't seem to be related to
2228 anything, try disabling/enabling this option (or disabling/enabling
2231 Some other things you should try when experiencing seemingly random,
2234 1) make sure that you have enough swap space and that it is
2236 2) pass the "no-hlt" option to the kernel
2237 3) switch on floating point emulation in the kernel and pass
2238 the "no387" option to the kernel
2239 4) pass the "floppy=nodma" option to the kernel
2240 5) pass the "mem=4M" option to the kernel (thereby disabling
2241 all but the first 4 MB of RAM)
2242 6) make sure that the CPU is not over clocked.
2243 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2244 8) disable the cache from your BIOS settings
2245 9) install a fan for the video card or exchange video RAM
2246 10) install a better fan for the CPU
2247 11) exchange RAM chips
2248 12) exchange the motherboard.
2250 To compile this driver as a module, choose M here: the
2251 module will be called apm.
2255 config APM_IGNORE_USER_SUSPEND
2256 bool "Ignore USER SUSPEND"
2258 This option will ignore USER SUSPEND requests. On machines with a
2259 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2260 series notebooks, it is necessary to say Y because of a BIOS bug.
2262 config APM_DO_ENABLE
2263 bool "Enable PM at boot time"
2265 Enable APM features at boot time. From page 36 of the APM BIOS
2266 specification: "When disabled, the APM BIOS does not automatically
2267 power manage devices, enter the Standby State, enter the Suspend
2268 State, or take power saving steps in response to CPU Idle calls."
2269 This driver will make CPU Idle calls when Linux is idle (unless this
2270 feature is turned off -- see "Do CPU IDLE calls", below). This
2271 should always save battery power, but more complicated APM features
2272 will be dependent on your BIOS implementation. You may need to turn
2273 this option off if your computer hangs at boot time when using APM
2274 support, or if it beeps continuously instead of suspending. Turn
2275 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2276 T400CDT. This is off by default since most machines do fine without
2281 bool "Make CPU Idle calls when idle"
2283 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2284 On some machines, this can activate improved power savings, such as
2285 a slowed CPU clock rate, when the machine is idle. These idle calls
2286 are made after the idle loop has run for some length of time (e.g.,
2287 333 mS). On some machines, this will cause a hang at boot time or
2288 whenever the CPU becomes idle. (On machines with more than one CPU,
2289 this option does nothing.)
2291 config APM_DISPLAY_BLANK
2292 bool "Enable console blanking using APM"
2294 Enable console blanking using the APM. Some laptops can use this to
2295 turn off the LCD backlight when the screen blanker of the Linux
2296 virtual console blanks the screen. Note that this is only used by
2297 the virtual console screen blanker, and won't turn off the backlight
2298 when using the X Window system. This also doesn't have anything to
2299 do with your VESA-compliant power-saving monitor. Further, this
2300 option doesn't work for all laptops -- it might not turn off your
2301 backlight at all, or it might print a lot of errors to the console,
2302 especially if you are using gpm.
2304 config APM_ALLOW_INTS
2305 bool "Allow interrupts during APM BIOS calls"
2307 Normally we disable external interrupts while we are making calls to
2308 the APM BIOS as a measure to lessen the effects of a badly behaving
2309 BIOS implementation. The BIOS should reenable interrupts if it
2310 needs to. Unfortunately, some BIOSes do not -- especially those in
2311 many of the newer IBM Thinkpads. If you experience hangs when you
2312 suspend, try setting this to Y. Otherwise, say N.
2316 source "drivers/cpufreq/Kconfig"
2318 source "drivers/cpuidle/Kconfig"
2320 source "drivers/idle/Kconfig"
2325 menu "Bus options (PCI etc.)"
2331 Find out whether you have a PCI motherboard. PCI is the name of a
2332 bus system, i.e. the way the CPU talks to the other stuff inside
2333 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2334 VESA. If you have PCI, say Y, otherwise N.
2337 prompt "PCI access mode"
2338 depends on X86_32 && PCI
2341 On PCI systems, the BIOS can be used to detect the PCI devices and
2342 determine their configuration. However, some old PCI motherboards
2343 have BIOS bugs and may crash if this is done. Also, some embedded
2344 PCI-based systems don't have any BIOS at all. Linux can also try to
2345 detect the PCI hardware directly without using the BIOS.
2347 With this option, you can specify how Linux should detect the
2348 PCI devices. If you choose "BIOS", the BIOS will be used,
2349 if you choose "Direct", the BIOS won't be used, and if you
2350 choose "MMConfig", then PCI Express MMCONFIG will be used.
2351 If you choose "Any", the kernel will try MMCONFIG, then the
2352 direct access method and falls back to the BIOS if that doesn't
2353 work. If unsure, go with the default, which is "Any".
2358 config PCI_GOMMCONFIG
2375 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2377 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2380 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2384 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2388 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2392 depends on PCI && XEN
2400 bool "Support mmconfig PCI config space access"
2401 depends on X86_64 && PCI && ACPI
2403 config PCI_CNB20LE_QUIRK
2404 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2407 Read the PCI windows out of the CNB20LE host bridge. This allows
2408 PCI hotplug to work on systems with the CNB20LE chipset which do
2411 There's no public spec for this chipset, and this functionality
2412 is known to be incomplete.
2414 You should say N unless you know you need this.
2416 source "drivers/pci/pcie/Kconfig"
2418 source "drivers/pci/Kconfig"
2420 # x86_64 have no ISA slots, but can have ISA-style DMA.
2422 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2425 Enables ISA-style DMA support for devices requiring such controllers.
2433 Find out whether you have ISA slots on your motherboard. ISA is the
2434 name of a bus system, i.e. the way the CPU talks to the other stuff
2435 inside your box. Other bus systems are PCI, EISA, MicroChannel
2436 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2437 newer boards don't support it. If you have ISA, say Y, otherwise N.
2443 The Extended Industry Standard Architecture (EISA) bus was
2444 developed as an open alternative to the IBM MicroChannel bus.
2446 The EISA bus provided some of the features of the IBM MicroChannel
2447 bus while maintaining backward compatibility with cards made for
2448 the older ISA bus. The EISA bus saw limited use between 1988 and
2449 1995 when it was made obsolete by the PCI bus.
2451 Say Y here if you are building a kernel for an EISA-based machine.
2455 source "drivers/eisa/Kconfig"
2458 tristate "NatSemi SCx200 support"
2460 This provides basic support for National Semiconductor's
2461 (now AMD's) Geode processors. The driver probes for the
2462 PCI-IDs of several on-chip devices, so its a good dependency
2463 for other scx200_* drivers.
2465 If compiled as a module, the driver is named scx200.
2467 config SCx200HR_TIMER
2468 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2472 This driver provides a clocksource built upon the on-chip
2473 27MHz high-resolution timer. Its also a workaround for
2474 NSC Geode SC-1100's buggy TSC, which loses time when the
2475 processor goes idle (as is done by the scheduler). The
2476 other workaround is idle=poll boot option.
2479 bool "One Laptop Per Child support"
2486 Add support for detecting the unique features of the OLPC
2490 bool "OLPC XO-1 Power Management"
2491 depends on OLPC && MFD_CS5535 && PM_SLEEP
2494 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2497 bool "OLPC XO-1 Real Time Clock"
2498 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2500 Add support for the XO-1 real time clock, which can be used as a
2501 programmable wakeup source.
2504 bool "OLPC XO-1 SCI extras"
2505 depends on OLPC && OLPC_XO1_PM
2511 Add support for SCI-based features of the OLPC XO-1 laptop:
2512 - EC-driven system wakeups
2516 - AC adapter status updates
2517 - Battery status updates
2519 config OLPC_XO15_SCI
2520 bool "OLPC XO-1.5 SCI extras"
2521 depends on OLPC && ACPI
2524 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2525 - EC-driven system wakeups
2526 - AC adapter status updates
2527 - Battery status updates
2530 bool "PCEngines ALIX System Support (LED setup)"
2533 This option enables system support for the PCEngines ALIX.
2534 At present this just sets up LEDs for GPIO control on
2535 ALIX2/3/6 boards. However, other system specific setup should
2538 Note: You must still enable the drivers for GPIO and LED support
2539 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2541 Note: You have to set alix.force=1 for boards with Award BIOS.
2544 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2547 This option enables system support for the Soekris Engineering net5501.
2550 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2554 This option enables system support for the Traverse Technologies GEOS.
2557 bool "Technologic Systems TS-5500 platform support"
2559 select CHECK_SIGNATURE
2563 This option enables system support for the Technologic Systems TS-5500.
2569 depends on CPU_SUP_AMD && PCI
2571 source "drivers/pcmcia/Kconfig"
2573 source "drivers/pci/hotplug/Kconfig"
2576 tristate "RapidIO support"
2580 If enabled this option will include drivers and the core
2581 infrastructure code to support RapidIO interconnect devices.
2583 source "drivers/rapidio/Kconfig"
2586 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2588 Firmwares often provide initial graphics framebuffers so the BIOS,
2589 bootloader or kernel can show basic video-output during boot for
2590 user-guidance and debugging. Historically, x86 used the VESA BIOS
2591 Extensions and EFI-framebuffers for this, which are mostly limited
2593 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2594 framebuffers so the new generic system-framebuffer drivers can be
2595 used on x86. If the framebuffer is not compatible with the generic
2596 modes, it is adverticed as fallback platform framebuffer so legacy
2597 drivers like efifb, vesafb and uvesafb can pick it up.
2598 If this option is not selected, all system framebuffers are always
2599 marked as fallback platform framebuffers as usual.
2601 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2602 not be able to pick up generic system framebuffers if this option
2603 is selected. You are highly encouraged to enable simplefb as
2604 replacement if you select this option. simplefb can correctly deal
2605 with generic system framebuffers. But you should still keep vesafb
2606 and others enabled as fallback if a system framebuffer is
2607 incompatible with simplefb.
2614 menu "Executable file formats / Emulations"
2616 source "fs/Kconfig.binfmt"
2618 config IA32_EMULATION
2619 bool "IA32 Emulation"
2622 select COMPAT_BINFMT_ELF
2623 select ARCH_WANT_OLD_COMPAT_IPC
2625 Include code to run legacy 32-bit programs under a
2626 64-bit kernel. You should likely turn this on, unless you're
2627 100% sure that you don't have any 32-bit programs left.
2630 tristate "IA32 a.out support"
2631 depends on IA32_EMULATION
2633 Support old a.out binaries in the 32bit emulation.
2636 bool "x32 ABI for 64-bit mode"
2639 Include code to run binaries for the x32 native 32-bit ABI
2640 for 64-bit processors. An x32 process gets access to the
2641 full 64-bit register file and wide data path while leaving
2642 pointers at 32 bits for smaller memory footprint.
2644 You will need a recent binutils (2.22 or later) with
2645 elf32_x86_64 support enabled to compile a kernel with this
2650 depends on IA32_EMULATION || X86_X32
2653 config COMPAT_FOR_U64_ALIGNMENT
2656 config SYSVIPC_COMPAT
2668 config HAVE_ATOMIC_IOMAP
2672 config X86_DEV_DMA_OPS
2674 depends on X86_64 || STA2X11
2676 config X86_DMA_REMAP
2684 source "net/Kconfig"
2686 source "drivers/Kconfig"
2688 source "drivers/firmware/Kconfig"
2692 source "arch/x86/Kconfig.debug"
2694 source "security/Kconfig"
2696 source "crypto/Kconfig"
2698 source "arch/x86/kvm/Kconfig"
2700 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob