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_DEVMEM_IS_ALLOWED
28 select ARCH_HAS_ELF_RANDOMIZE
29 select ARCH_HAS_FAST_MULTIPLIER
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_KCOV if X86_64
32 select ARCH_HAS_PMEM_API if X86_64
33 select ARCH_HAS_MMIO_FLUSH
34 select ARCH_HAS_SG_CHAIN
35 select ARCH_HAS_UBSAN_SANITIZE_ALL
36 select ARCH_HAVE_NMI_SAFE_CMPXCHG
37 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
38 select ARCH_MIGHT_HAVE_PC_PARPORT
39 select ARCH_MIGHT_HAVE_PC_SERIO
40 select ARCH_SUPPORTS_ATOMIC_RMW
41 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
42 select ARCH_SUPPORTS_INT128 if X86_64
43 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
44 select ARCH_USE_BUILTIN_BSWAP
45 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
46 select ARCH_USE_QUEUED_RWLOCKS
47 select ARCH_USE_QUEUED_SPINLOCKS
48 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
49 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
50 select ARCH_WANT_FRAME_POINTERS
51 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
52 select ARCH_WANT_OPTIONAL_GPIOLIB
53 select BUILDTIME_EXTABLE_SORT
55 select CLKSRC_I8253 if X86_32
56 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
57 select CLOCKSOURCE_WATCHDOG
58 select CLONE_BACKWARDS if X86_32
59 select COMPAT_OLD_SIGACTION if IA32_EMULATION
60 select DCACHE_WORD_ACCESS
61 select EDAC_ATOMIC_SCRUB
63 select GENERIC_CLOCKEVENTS
64 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
65 select GENERIC_CLOCKEVENTS_MIN_ADJUST
66 select GENERIC_CMOS_UPDATE
67 select GENERIC_CPU_AUTOPROBE
68 select GENERIC_EARLY_IOREMAP
69 select GENERIC_FIND_FIRST_BIT
71 select GENERIC_IRQ_PROBE
72 select GENERIC_IRQ_SHOW
73 select GENERIC_PENDING_IRQ if SMP
74 select GENERIC_SMP_IDLE_THREAD
75 select GENERIC_STRNCPY_FROM_USER
76 select GENERIC_STRNLEN_USER
77 select GENERIC_TIME_VSYSCALL
78 select HAVE_ACPI_APEI if ACPI
79 select HAVE_ACPI_APEI_NMI if ACPI
80 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
81 select HAVE_AOUT if X86_32
82 select HAVE_ARCH_AUDITSYSCALL
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_MMAP_RND_BITS if MMU
89 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
90 select HAVE_ARCH_SECCOMP_FILTER
91 select HAVE_ARCH_SOFT_DIRTY if X86_64
92 select HAVE_ARCH_TRACEHOOK
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
94 select HAVE_BPF_JIT if X86_64
95 select HAVE_CC_STACKPROTECTOR
96 select HAVE_CMPXCHG_DOUBLE
97 select HAVE_CMPXCHG_LOCAL
98 select HAVE_CONTEXT_TRACKING if X86_64
99 select HAVE_COPY_THREAD_TLS
100 select HAVE_C_RECORDMCOUNT
101 select HAVE_DEBUG_KMEMLEAK
102 select HAVE_DEBUG_STACKOVERFLOW
103 select HAVE_DMA_API_DEBUG
104 select HAVE_DMA_CONTIGUOUS
105 select HAVE_DYNAMIC_FTRACE
106 select HAVE_DYNAMIC_FTRACE_WITH_REGS
107 select HAVE_EFFICIENT_UNALIGNED_ACCESS
108 select HAVE_FENTRY if X86_64
109 select HAVE_FTRACE_MCOUNT_RECORD
110 select HAVE_FUNCTION_GRAPH_FP_TEST
111 select HAVE_FUNCTION_GRAPH_TRACER
112 select HAVE_FUNCTION_TRACER
113 select HAVE_GENERIC_DMA_COHERENT if X86_32
114 select HAVE_HW_BREAKPOINT
116 select HAVE_IOREMAP_PROT
117 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
118 select HAVE_IRQ_TIME_ACCOUNTING
119 select HAVE_KERNEL_BZIP2
120 select HAVE_KERNEL_GZIP
121 select HAVE_KERNEL_LZ4
122 select HAVE_KERNEL_LZMA
123 select HAVE_KERNEL_LZO
124 select HAVE_KERNEL_XZ
126 select HAVE_KPROBES_ON_FTRACE
127 select HAVE_KRETPROBES
129 select HAVE_LIVEPATCH if X86_64
131 select HAVE_MEMBLOCK_NODE_MAP
132 select HAVE_MIXED_BREAKPOINTS_REGS
134 select HAVE_OPTPROBES
135 select HAVE_PCSPKR_PLATFORM
136 select HAVE_PERF_EVENTS
137 select HAVE_PERF_EVENTS_NMI
138 select HAVE_PERF_REGS
139 select HAVE_PERF_USER_STACK_DUMP
140 select HAVE_REGS_AND_STACK_ACCESS_API
141 select HAVE_SYSCALL_TRACEPOINTS
142 select HAVE_UID16 if X86_32 || IA32_EMULATION
143 select HAVE_UNSTABLE_SCHED_CLOCK
144 select HAVE_USER_RETURN_NOTIFIER
145 select IRQ_FORCED_THREADING
146 select MODULES_USE_ELF_RELA if X86_64
147 select MODULES_USE_ELF_REL if X86_32
148 select OLD_SIGACTION if X86_32
149 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
154 select SYSCTL_EXCEPTION_TRACE
155 select USER_STACKTRACE_SUPPORT
157 select X86_DEV_DMA_OPS if X86_64
158 select X86_FEATURE_NAMES if PROC_FS
159 select HAVE_STACK_VALIDATION if X86_64
160 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
161 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
163 config INSTRUCTION_DECODER
165 depends on KPROBES || PERF_EVENTS || UPROBES
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
186 config ARCH_MMAP_RND_BITS_MIN
190 config ARCH_MMAP_RND_BITS_MAX
194 config ARCH_MMAP_RND_COMPAT_BITS_MIN
197 config ARCH_MMAP_RND_COMPAT_BITS_MAX
203 config NEED_DMA_MAP_STATE
205 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
207 config NEED_SG_DMA_LENGTH
210 config GENERIC_ISA_DMA
212 depends on ISA_DMA_API
217 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
219 config GENERIC_BUG_RELATIVE_POINTERS
222 config GENERIC_HWEIGHT
225 config ARCH_MAY_HAVE_PC_FDC
227 depends on ISA_DMA_API
229 config RWSEM_XCHGADD_ALGORITHM
232 config GENERIC_CALIBRATE_DELAY
235 config ARCH_HAS_CPU_RELAX
238 config ARCH_HAS_CACHE_LINE_SIZE
241 config HAVE_SETUP_PER_CPU_AREA
244 config NEED_PER_CPU_EMBED_FIRST_CHUNK
247 config NEED_PER_CPU_PAGE_FIRST_CHUNK
250 config ARCH_HIBERNATION_POSSIBLE
253 config ARCH_SUSPEND_POSSIBLE
256 config ARCH_WANT_HUGE_PMD_SHARE
259 config ARCH_WANT_GENERAL_HUGETLB
268 config ARCH_SUPPORTS_OPTIMIZED_INLINING
271 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
274 config KASAN_SHADOW_OFFSET
277 default 0xdffffc0000000000
279 config HAVE_INTEL_TXT
281 depends on INTEL_IOMMU && ACPI
285 depends on X86_32 && SMP
289 depends on X86_64 && SMP
291 config X86_32_LAZY_GS
293 depends on X86_32 && !CC_STACKPROTECTOR
295 config ARCH_HWEIGHT_CFLAGS
297 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
298 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
300 config ARCH_SUPPORTS_UPROBES
303 config FIX_EARLYCON_MEM
309 config PGTABLE_LEVELS
315 source "init/Kconfig"
316 source "kernel/Kconfig.freezer"
318 menu "Processor type and features"
321 bool "DMA memory allocation support" if EXPERT
324 DMA memory allocation support allows devices with less than 32-bit
325 addressing to allocate within the first 16MB of address space.
326 Disable if no such devices will be used.
331 bool "Symmetric multi-processing support"
333 This enables support for systems with more than one CPU. If you have
334 a system with only one CPU, say N. If you have a system with more
337 If you say N here, the kernel will run on uni- and multiprocessor
338 machines, but will use only one CPU of a multiprocessor machine. If
339 you say Y here, the kernel will run on many, but not all,
340 uniprocessor machines. On a uniprocessor machine, the kernel
341 will run faster if you say N here.
343 Note that if you say Y here and choose architecture "586" or
344 "Pentium" under "Processor family", the kernel will not work on 486
345 architectures. Similarly, multiprocessor kernels for the "PPro"
346 architecture may not work on all Pentium based boards.
348 People using multiprocessor machines who say Y here should also say
349 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
350 Management" code will be disabled if you say Y here.
352 See also <file:Documentation/x86/i386/IO-APIC.txt>,
353 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
354 <http://www.tldp.org/docs.html#howto>.
356 If you don't know what to do here, say N.
358 config X86_FEATURE_NAMES
359 bool "Processor feature human-readable names" if EMBEDDED
362 This option compiles in a table of x86 feature bits and corresponding
363 names. This is required to support /proc/cpuinfo and a few kernel
364 messages. You can disable this to save space, at the expense of
365 making those few kernel messages show numeric feature bits instead.
369 config X86_FAST_FEATURE_TESTS
370 bool "Fast CPU feature tests" if EMBEDDED
373 Some fast-paths in the kernel depend on the capabilities of the CPU.
374 Say Y here for the kernel to patch in the appropriate code at runtime
375 based on the capabilities of the CPU. The infrastructure for patching
376 code at runtime takes up some additional space; space-constrained
377 embedded systems may wish to say N here to produce smaller, slightly
381 bool "Support x2apic"
382 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
384 This enables x2apic support on CPUs that have this feature.
386 This allows 32-bit apic IDs (so it can support very large systems),
387 and accesses the local apic via MSRs not via mmio.
389 If you don't know what to do here, say N.
392 bool "Enable MPS table" if ACPI || SFI
394 depends on X86_LOCAL_APIC
396 For old smp systems that do not have proper acpi support. Newer systems
397 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
400 bool "Support for big SMP systems with more than 8 CPUs"
401 depends on X86_32 && SMP
403 This option is needed for the systems that have more than 8 CPUs
407 depends on X86_GOLDFISH
410 config X86_EXTENDED_PLATFORM
411 bool "Support for extended (non-PC) x86 platforms"
414 If you disable this option then the kernel will only support
415 standard PC platforms. (which covers the vast majority of
418 If you enable this option then you'll be able to select support
419 for the following (non-PC) 32 bit x86 platforms:
420 Goldfish (Android emulator)
423 SGI 320/540 (Visual Workstation)
424 STA2X11-based (e.g. Northville)
425 Moorestown MID devices
427 If you have one of these systems, or if you want to build a
428 generic distribution kernel, say Y here - otherwise say N.
432 config X86_EXTENDED_PLATFORM
433 bool "Support for extended (non-PC) x86 platforms"
436 If you disable this option then the kernel will only support
437 standard PC platforms. (which covers the vast majority of
440 If you enable this option then you'll be able to select support
441 for the following (non-PC) 64 bit x86 platforms:
446 If you have one of these systems, or if you want to build a
447 generic distribution kernel, say Y here - otherwise say N.
449 # This is an alphabetically sorted list of 64 bit extended platforms
450 # Please maintain the alphabetic order if and when there are additions
452 bool "Numascale NumaChip"
454 depends on X86_EXTENDED_PLATFORM
457 depends on X86_X2APIC
458 depends on PCI_MMCONFIG
460 Adds support for Numascale NumaChip large-SMP systems. Needed to
461 enable more than ~168 cores.
462 If you don't have one of these, you should say N here.
466 select HYPERVISOR_GUEST
468 depends on X86_64 && PCI
469 depends on X86_EXTENDED_PLATFORM
472 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
473 supposed to run on these EM64T-based machines. Only choose this option
474 if you have one of these machines.
477 bool "SGI Ultraviolet"
479 depends on X86_EXTENDED_PLATFORM
482 depends on X86_X2APIC
485 This option is needed in order to support SGI Ultraviolet systems.
486 If you don't have one of these, you should say N here.
488 # Following is an alphabetically sorted list of 32 bit extended platforms
489 # Please maintain the alphabetic order if and when there are additions
492 bool "Goldfish (Virtual Platform)"
493 depends on X86_EXTENDED_PLATFORM
495 Enable support for the Goldfish virtual platform used primarily
496 for Android development. Unless you are building for the Android
497 Goldfish emulator say N here.
500 bool "CE4100 TV platform"
502 depends on PCI_GODIRECT
503 depends on X86_IO_APIC
505 depends on X86_EXTENDED_PLATFORM
506 select X86_REBOOTFIXUPS
508 select OF_EARLY_FLATTREE
510 Select for the Intel CE media processor (CE4100) SOC.
511 This option compiles in support for the CE4100 SOC for settop
512 boxes and media devices.
515 bool "Intel MID platform support"
516 depends on X86_EXTENDED_PLATFORM
517 depends on X86_PLATFORM_DEVICES
519 depends on X86_64 || (PCI_GOANY && X86_32)
520 depends on X86_IO_APIC
526 select MFD_INTEL_MSIC
528 Select to build a kernel capable of supporting Intel MID (Mobile
529 Internet Device) platform systems which do not have the PCI legacy
530 interfaces. If you are building for a PC class system say N here.
532 Intel MID platforms are based on an Intel processor and chipset which
533 consume less power than most of the x86 derivatives.
535 config X86_INTEL_QUARK
536 bool "Intel Quark platform support"
538 depends on X86_EXTENDED_PLATFORM
539 depends on X86_PLATFORM_DEVICES
543 depends on X86_IO_APIC
548 Select to include support for Quark X1000 SoC.
549 Say Y here if you have a Quark based system such as the Arduino
550 compatible Intel Galileo.
552 config X86_INTEL_LPSS
553 bool "Intel Low Power Subsystem Support"
554 depends on X86 && ACPI
559 Select to build support for Intel Low Power Subsystem such as
560 found on Intel Lynxpoint PCH. Selecting this option enables
561 things like clock tree (common clock framework) and pincontrol
562 which are needed by the LPSS peripheral drivers.
564 config X86_AMD_PLATFORM_DEVICE
565 bool "AMD ACPI2Platform devices support"
570 Select to interpret AMD specific ACPI device to platform device
571 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
572 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
573 implemented under PINCTRL subsystem.
576 tristate "Intel SoC IOSF Sideband support for SoC platforms"
579 This option enables sideband register access support for Intel SoC
580 platforms. On these platforms the IOSF sideband is used in lieu of
581 MSR's for some register accesses, mostly but not limited to thermal
582 and power. Drivers may query the availability of this device to
583 determine if they need the sideband in order to work on these
584 platforms. The sideband is available on the following SoC products.
585 This list is not meant to be exclusive.
590 You should say Y if you are running a kernel on one of these SoC's.
592 config IOSF_MBI_DEBUG
593 bool "Enable IOSF sideband access through debugfs"
594 depends on IOSF_MBI && DEBUG_FS
596 Select this option to expose the IOSF sideband access registers (MCR,
597 MDR, MCRX) through debugfs to write and read register information from
598 different units on the SoC. This is most useful for obtaining device
599 state information for debug and analysis. As this is a general access
600 mechanism, users of this option would have specific knowledge of the
601 device they want to access.
603 If you don't require the option or are in doubt, say N.
606 bool "RDC R-321x SoC"
608 depends on X86_EXTENDED_PLATFORM
610 select X86_REBOOTFIXUPS
612 This option is needed for RDC R-321x system-on-chip, also known
614 If you don't have one of these chips, you should say N here.
616 config X86_32_NON_STANDARD
617 bool "Support non-standard 32-bit SMP architectures"
618 depends on X86_32 && SMP
619 depends on X86_EXTENDED_PLATFORM
621 This option compiles in the bigsmp and STA2X11 default
622 subarchitectures. It is intended for a generic binary
623 kernel. If you select them all, kernel will probe it one by
624 one and will fallback to default.
626 # Alphabetically sorted list of Non standard 32 bit platforms
628 config X86_SUPPORTS_MEMORY_FAILURE
630 # MCE code calls memory_failure():
632 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
633 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
634 depends on X86_64 || !SPARSEMEM
635 select ARCH_SUPPORTS_MEMORY_FAILURE
638 bool "STA2X11 Companion Chip Support"
639 depends on X86_32_NON_STANDARD && PCI
640 select X86_DEV_DMA_OPS
644 select ARCH_REQUIRE_GPIOLIB
647 This adds support for boards based on the STA2X11 IO-Hub,
648 a.k.a. "ConneXt". The chip is used in place of the standard
649 PC chipset, so all "standard" peripherals are missing. If this
650 option is selected the kernel will still be able to boot on
651 standard PC machines.
654 tristate "Eurobraille/Iris poweroff module"
657 The Iris machines from EuroBraille do not have APM or ACPI support
658 to shut themselves down properly. A special I/O sequence is
659 needed to do so, which is what this module does at
662 This is only for Iris machines from EuroBraille.
666 config SCHED_OMIT_FRAME_POINTER
668 prompt "Single-depth WCHAN output"
671 Calculate simpler /proc/<PID>/wchan values. If this option
672 is disabled then wchan values will recurse back to the
673 caller function. This provides more accurate wchan values,
674 at the expense of slightly more scheduling overhead.
676 If in doubt, say "Y".
678 menuconfig HYPERVISOR_GUEST
679 bool "Linux guest support"
681 Say Y here to enable options for running Linux under various hyper-
682 visors. This option enables basic hypervisor detection and platform
685 If you say N, all options in this submenu will be skipped and
686 disabled, and Linux guest support won't be built in.
691 bool "Enable paravirtualization code"
693 This changes the kernel so it can modify itself when it is run
694 under a hypervisor, potentially improving performance significantly
695 over full virtualization. However, when run without a hypervisor
696 the kernel is theoretically slower and slightly larger.
698 config PARAVIRT_DEBUG
699 bool "paravirt-ops debugging"
700 depends on PARAVIRT && DEBUG_KERNEL
702 Enable to debug paravirt_ops internals. Specifically, BUG if
703 a paravirt_op is missing when it is called.
705 config PARAVIRT_SPINLOCKS
706 bool "Paravirtualization layer for spinlocks"
707 depends on PARAVIRT && SMP
708 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
710 Paravirtualized spinlocks allow a pvops backend to replace the
711 spinlock implementation with something virtualization-friendly
712 (for example, block the virtual CPU rather than spinning).
714 It has a minimal impact on native kernels and gives a nice performance
715 benefit on paravirtualized KVM / Xen kernels.
717 If you are unsure how to answer this question, answer Y.
719 config QUEUED_LOCK_STAT
720 bool "Paravirt queued spinlock statistics"
721 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
723 Enable the collection of statistical data on the slowpath
724 behavior of paravirtualized queued spinlocks and report
727 source "arch/x86/xen/Kconfig"
730 bool "KVM Guest support (including kvmclock)"
732 select PARAVIRT_CLOCK
735 This option enables various optimizations for running under the KVM
736 hypervisor. It includes a paravirtualized clock, so that instead
737 of relying on a PIT (or probably other) emulation by the
738 underlying device model, the host provides the guest with
739 timing infrastructure such as time of day, and system time
742 bool "Enable debug information for KVM Guests in debugfs"
743 depends on KVM_GUEST && DEBUG_FS
746 This option enables collection of various statistics for KVM guest.
747 Statistics are displayed in debugfs filesystem. Enabling this option
748 may incur significant overhead.
750 source "arch/x86/lguest/Kconfig"
752 config PARAVIRT_TIME_ACCOUNTING
753 bool "Paravirtual steal time accounting"
757 Select this option to enable fine granularity task steal time
758 accounting. Time spent executing other tasks in parallel with
759 the current vCPU is discounted from the vCPU power. To account for
760 that, there can be a small performance impact.
762 If in doubt, say N here.
764 config PARAVIRT_CLOCK
767 endif #HYPERVISOR_GUEST
772 source "arch/x86/Kconfig.cpu"
776 prompt "HPET Timer Support" if X86_32
778 Use the IA-PC HPET (High Precision Event Timer) to manage
779 time in preference to the PIT and RTC, if a HPET is
781 HPET is the next generation timer replacing legacy 8254s.
782 The HPET provides a stable time base on SMP
783 systems, unlike the TSC, but it is more expensive to access,
784 as it is off-chip. The interface used is documented
785 in the HPET spec, revision 1.
787 You can safely choose Y here. However, HPET will only be
788 activated if the platform and the BIOS support this feature.
789 Otherwise the 8254 will be used for timing services.
791 Choose N to continue using the legacy 8254 timer.
793 config HPET_EMULATE_RTC
795 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
798 def_bool y if X86_INTEL_MID
799 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
801 depends on X86_INTEL_MID && SFI
803 APB timer is the replacement for 8254, HPET on X86 MID platforms.
804 The APBT provides a stable time base on SMP
805 systems, unlike the TSC, but it is more expensive to access,
806 as it is off-chip. APB timers are always running regardless of CPU
807 C states, they are used as per CPU clockevent device when possible.
809 # Mark as expert because too many people got it wrong.
810 # The code disables itself when not needed.
813 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
814 bool "Enable DMI scanning" if EXPERT
816 Enabled scanning of DMI to identify machine quirks. Say Y
817 here unless you have verified that your setup is not
818 affected by entries in the DMI blacklist. Required by PNP
822 bool "Old AMD GART IOMMU support"
824 depends on X86_64 && PCI && AMD_NB
826 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
827 GART based hardware IOMMUs.
829 The GART supports full DMA access for devices with 32-bit access
830 limitations, on systems with more than 3 GB. This is usually needed
831 for USB, sound, many IDE/SATA chipsets and some other devices.
833 Newer systems typically have a modern AMD IOMMU, supported via
834 the CONFIG_AMD_IOMMU=y config option.
836 In normal configurations this driver is only active when needed:
837 there's more than 3 GB of memory and the system contains a
838 32-bit limited device.
843 bool "IBM Calgary IOMMU support"
845 depends on X86_64 && PCI
847 Support for hardware IOMMUs in IBM's xSeries x366 and x460
848 systems. Needed to run systems with more than 3GB of memory
849 properly with 32-bit PCI devices that do not support DAC
850 (Double Address Cycle). Calgary also supports bus level
851 isolation, where all DMAs pass through the IOMMU. This
852 prevents them from going anywhere except their intended
853 destination. This catches hard-to-find kernel bugs and
854 mis-behaving drivers and devices that do not use the DMA-API
855 properly to set up their DMA buffers. The IOMMU can be
856 turned off at boot time with the iommu=off parameter.
857 Normally the kernel will make the right choice by itself.
860 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
862 prompt "Should Calgary be enabled by default?"
863 depends on CALGARY_IOMMU
865 Should Calgary be enabled by default? if you choose 'y', Calgary
866 will be used (if it exists). If you choose 'n', Calgary will not be
867 used even if it exists. If you choose 'n' and would like to use
868 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
871 # need this always selected by IOMMU for the VIA workaround
875 Support for software bounce buffers used on x86-64 systems
876 which don't have a hardware IOMMU. Using this PCI devices
877 which can only access 32-bits of memory can be used on systems
878 with more than 3 GB of memory.
883 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
886 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
887 depends on X86_64 && SMP && DEBUG_KERNEL
888 select CPUMASK_OFFSTACK
890 Enable maximum number of CPUS and NUMA Nodes for this architecture.
894 int "Maximum number of CPUs" if SMP && !MAXSMP
895 range 2 8 if SMP && X86_32 && !X86_BIGSMP
896 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
897 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
899 default "8192" if MAXSMP
900 default "32" if SMP && X86_BIGSMP
901 default "8" if SMP && X86_32
904 This allows you to specify the maximum number of CPUs which this
905 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
906 supported value is 8192, otherwise the maximum value is 512. The
907 minimum value which makes sense is 2.
909 This is purely to save memory - each supported CPU adds
910 approximately eight kilobytes to the kernel image.
913 bool "SMT (Hyperthreading) scheduler support"
916 SMT scheduler support improves the CPU scheduler's decision making
917 when dealing with Intel Pentium 4 chips with HyperThreading at a
918 cost of slightly increased overhead in some places. If unsure say
923 prompt "Multi-core scheduler support"
926 Multi-core scheduler support improves the CPU scheduler's decision
927 making when dealing with multi-core CPU chips at a cost of slightly
928 increased overhead in some places. If unsure say N here.
930 source "kernel/Kconfig.preempt"
934 depends on !SMP && X86_LOCAL_APIC
937 bool "Local APIC support on uniprocessors" if !PCI_MSI
939 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
941 A local APIC (Advanced Programmable Interrupt Controller) is an
942 integrated interrupt controller in the CPU. If you have a single-CPU
943 system which has a processor with a local APIC, you can say Y here to
944 enable and use it. If you say Y here even though your machine doesn't
945 have a local APIC, then the kernel will still run with no slowdown at
946 all. The local APIC supports CPU-generated self-interrupts (timer,
947 performance counters), and the NMI watchdog which detects hard
951 bool "IO-APIC support on uniprocessors"
952 depends on X86_UP_APIC
954 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
955 SMP-capable replacement for PC-style interrupt controllers. Most
956 SMP systems and many recent uniprocessor systems have one.
958 If you have a single-CPU system with an IO-APIC, you can say Y here
959 to use it. If you say Y here even though your machine doesn't have
960 an IO-APIC, then the kernel will still run with no slowdown at all.
962 config X86_LOCAL_APIC
964 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
965 select IRQ_DOMAIN_HIERARCHY
966 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
970 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
972 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
973 bool "Reroute for broken boot IRQs"
974 depends on X86_IO_APIC
976 This option enables a workaround that fixes a source of
977 spurious interrupts. This is recommended when threaded
978 interrupt handling is used on systems where the generation of
979 superfluous "boot interrupts" cannot be disabled.
981 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
982 entry in the chipset's IO-APIC is masked (as, e.g. the RT
983 kernel does during interrupt handling). On chipsets where this
984 boot IRQ generation cannot be disabled, this workaround keeps
985 the original IRQ line masked so that only the equivalent "boot
986 IRQ" is delivered to the CPUs. The workaround also tells the
987 kernel to set up the IRQ handler on the boot IRQ line. In this
988 way only one interrupt is delivered to the kernel. Otherwise
989 the spurious second interrupt may cause the kernel to bring
990 down (vital) interrupt lines.
992 Only affects "broken" chipsets. Interrupt sharing may be
993 increased on these systems.
996 bool "Machine Check / overheating reporting"
997 select GENERIC_ALLOCATOR
1000 Machine Check support allows the processor to notify the
1001 kernel if it detects a problem (e.g. overheating, data corruption).
1002 The action the kernel takes depends on the severity of the problem,
1003 ranging from warning messages to halting the machine.
1005 config X86_MCE_INTEL
1007 prompt "Intel MCE features"
1008 depends on X86_MCE && X86_LOCAL_APIC
1010 Additional support for intel specific MCE features such as
1011 the thermal monitor.
1015 prompt "AMD MCE features"
1016 depends on X86_MCE && X86_LOCAL_APIC
1018 Additional support for AMD specific MCE features such as
1019 the DRAM Error Threshold.
1021 config X86_ANCIENT_MCE
1022 bool "Support for old Pentium 5 / WinChip machine checks"
1023 depends on X86_32 && X86_MCE
1025 Include support for machine check handling on old Pentium 5 or WinChip
1026 systems. These typically need to be enabled explicitly on the command
1029 config X86_MCE_THRESHOLD
1030 depends on X86_MCE_AMD || X86_MCE_INTEL
1033 config X86_MCE_INJECT
1035 tristate "Machine check injector support"
1037 Provide support for injecting machine checks for testing purposes.
1038 If you don't know what a machine check is and you don't do kernel
1039 QA it is safe to say n.
1041 config X86_THERMAL_VECTOR
1043 depends on X86_MCE_INTEL
1045 source "arch/x86/events/Kconfig"
1047 config X86_LEGACY_VM86
1048 bool "Legacy VM86 support"
1052 This option allows user programs to put the CPU into V8086
1053 mode, which is an 80286-era approximation of 16-bit real mode.
1055 Some very old versions of X and/or vbetool require this option
1056 for user mode setting. Similarly, DOSEMU will use it if
1057 available to accelerate real mode DOS programs. However, any
1058 recent version of DOSEMU, X, or vbetool should be fully
1059 functional even without kernel VM86 support, as they will all
1060 fall back to software emulation. Nevertheless, if you are using
1061 a 16-bit DOS program where 16-bit performance matters, vm86
1062 mode might be faster than emulation and you might want to
1065 Note that any app that works on a 64-bit kernel is unlikely to
1066 need this option, as 64-bit kernels don't, and can't, support
1067 V8086 mode. This option is also unrelated to 16-bit protected
1068 mode and is not needed to run most 16-bit programs under Wine.
1070 Enabling this option increases the complexity of the kernel
1071 and slows down exception handling a tiny bit.
1073 If unsure, say N here.
1077 default X86_LEGACY_VM86
1080 bool "Enable support for 16-bit segments" if EXPERT
1082 depends on MODIFY_LDT_SYSCALL
1084 This option is required by programs like Wine to run 16-bit
1085 protected mode legacy code on x86 processors. Disabling
1086 this option saves about 300 bytes on i386, or around 6K text
1087 plus 16K runtime memory on x86-64,
1091 depends on X86_16BIT && X86_32
1095 depends on X86_16BIT && X86_64
1097 config X86_VSYSCALL_EMULATION
1098 bool "Enable vsyscall emulation" if EXPERT
1102 This enables emulation of the legacy vsyscall page. Disabling
1103 it is roughly equivalent to booting with vsyscall=none, except
1104 that it will also disable the helpful warning if a program
1105 tries to use a vsyscall. With this option set to N, offending
1106 programs will just segfault, citing addresses of the form
1109 This option is required by many programs built before 2013, and
1110 care should be used even with newer programs if set to N.
1112 Disabling this option saves about 7K of kernel size and
1113 possibly 4K of additional runtime pagetable memory.
1116 tristate "Toshiba Laptop support"
1119 This adds a driver to safely access the System Management Mode of
1120 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1121 not work on models with a Phoenix BIOS. The System Management Mode
1122 is used to set the BIOS and power saving options on Toshiba portables.
1124 For information on utilities to make use of this driver see the
1125 Toshiba Linux utilities web site at:
1126 <http://www.buzzard.org.uk/toshiba/>.
1128 Say Y if you intend to run this kernel on a Toshiba portable.
1132 tristate "Dell i8k legacy laptop support"
1134 select SENSORS_DELL_SMM
1136 This option enables legacy /proc/i8k userspace interface in hwmon
1137 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1138 temperature and allows controlling fan speeds of Dell laptops via
1139 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1140 it reports also power and hotkey status. For fan speed control is
1141 needed userspace package i8kutils.
1143 Say Y if you intend to run this kernel on old Dell laptops or want to
1144 use userspace package i8kutils.
1147 config X86_REBOOTFIXUPS
1148 bool "Enable X86 board specific fixups for reboot"
1151 This enables chipset and/or board specific fixups to be done
1152 in order to get reboot to work correctly. This is only needed on
1153 some combinations of hardware and BIOS. The symptom, for which
1154 this config is intended, is when reboot ends with a stalled/hung
1157 Currently, the only fixup is for the Geode machines using
1158 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1160 Say Y if you want to enable the fixup. Currently, it's safe to
1161 enable this option even if you don't need it.
1165 bool "CPU microcode loading support"
1167 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1170 If you say Y here, you will be able to update the microcode on
1171 Intel and AMD processors. The Intel support is for the IA32 family,
1172 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1173 AMD support is for families 0x10 and later. You will obviously need
1174 the actual microcode binary data itself which is not shipped with
1177 The preferred method to load microcode from a detached initrd is described
1178 in Documentation/x86/early-microcode.txt. For that you need to enable
1179 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1180 initrd for microcode blobs.
1182 In addition, you can build-in the microcode into the kernel. For that you
1183 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1184 to the CONFIG_EXTRA_FIRMWARE config option.
1186 config MICROCODE_INTEL
1187 bool "Intel microcode loading support"
1188 depends on MICROCODE
1192 This options enables microcode patch loading support for Intel
1195 For the current Intel microcode data package go to
1196 <https://downloadcenter.intel.com> and search for
1197 'Linux Processor Microcode Data File'.
1199 config MICROCODE_AMD
1200 bool "AMD microcode loading support"
1201 depends on MICROCODE
1204 If you select this option, microcode patch loading support for AMD
1205 processors will be enabled.
1207 config MICROCODE_OLD_INTERFACE
1209 depends on MICROCODE
1212 tristate "/dev/cpu/*/msr - Model-specific register support"
1214 This device gives privileged processes access to the x86
1215 Model-Specific Registers (MSRs). It is a character device with
1216 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1217 MSR accesses are directed to a specific CPU on multi-processor
1221 tristate "/dev/cpu/*/cpuid - CPU information support"
1223 This device gives processes access to the x86 CPUID instruction to
1224 be executed on a specific processor. It is a character device
1225 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1229 prompt "High Memory Support"
1236 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1237 However, the address space of 32-bit x86 processors is only 4
1238 Gigabytes large. That means that, if you have a large amount of
1239 physical memory, not all of it can be "permanently mapped" by the
1240 kernel. The physical memory that's not permanently mapped is called
1243 If you are compiling a kernel which will never run on a machine with
1244 more than 1 Gigabyte total physical RAM, answer "off" here (default
1245 choice and suitable for most users). This will result in a "3GB/1GB"
1246 split: 3GB are mapped so that each process sees a 3GB virtual memory
1247 space and the remaining part of the 4GB virtual memory space is used
1248 by the kernel to permanently map as much physical memory as
1251 If the machine has between 1 and 4 Gigabytes physical RAM, then
1254 If more than 4 Gigabytes is used then answer "64GB" here. This
1255 selection turns Intel PAE (Physical Address Extension) mode on.
1256 PAE implements 3-level paging on IA32 processors. PAE is fully
1257 supported by Linux, PAE mode is implemented on all recent Intel
1258 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1259 then the kernel will not boot on CPUs that don't support PAE!
1261 The actual amount of total physical memory will either be
1262 auto detected or can be forced by using a kernel command line option
1263 such as "mem=256M". (Try "man bootparam" or see the documentation of
1264 your boot loader (lilo or loadlin) about how to pass options to the
1265 kernel at boot time.)
1267 If unsure, say "off".
1272 Select this if you have a 32-bit processor and between 1 and 4
1273 gigabytes of physical RAM.
1280 Select this if you have a 32-bit processor and more than 4
1281 gigabytes of physical RAM.
1286 prompt "Memory split" if EXPERT
1290 Select the desired split between kernel and user memory.
1292 If the address range available to the kernel is less than the
1293 physical memory installed, the remaining memory will be available
1294 as "high memory". Accessing high memory is a little more costly
1295 than low memory, as it needs to be mapped into the kernel first.
1296 Note that increasing the kernel address space limits the range
1297 available to user programs, making the address space there
1298 tighter. Selecting anything other than the default 3G/1G split
1299 will also likely make your kernel incompatible with binary-only
1302 If you are not absolutely sure what you are doing, leave this
1306 bool "3G/1G user/kernel split"
1307 config VMSPLIT_3G_OPT
1309 bool "3G/1G user/kernel split (for full 1G low memory)"
1311 bool "2G/2G user/kernel split"
1312 config VMSPLIT_2G_OPT
1314 bool "2G/2G user/kernel split (for full 2G low memory)"
1316 bool "1G/3G user/kernel split"
1321 default 0xB0000000 if VMSPLIT_3G_OPT
1322 default 0x80000000 if VMSPLIT_2G
1323 default 0x78000000 if VMSPLIT_2G_OPT
1324 default 0x40000000 if VMSPLIT_1G
1330 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1333 bool "PAE (Physical Address Extension) Support"
1334 depends on X86_32 && !HIGHMEM4G
1337 PAE is required for NX support, and furthermore enables
1338 larger swapspace support for non-overcommit purposes. It
1339 has the cost of more pagetable lookup overhead, and also
1340 consumes more pagetable space per process.
1342 config ARCH_PHYS_ADDR_T_64BIT
1344 depends on X86_64 || X86_PAE
1346 config ARCH_DMA_ADDR_T_64BIT
1348 depends on X86_64 || HIGHMEM64G
1350 config X86_DIRECT_GBPAGES
1352 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1354 Certain kernel features effectively disable kernel
1355 linear 1 GB mappings (even if the CPU otherwise
1356 supports them), so don't confuse the user by printing
1357 that we have them enabled.
1359 # Common NUMA Features
1361 bool "Numa Memory Allocation and Scheduler Support"
1363 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1364 default y if X86_BIGSMP
1366 Enable NUMA (Non Uniform Memory Access) support.
1368 The kernel will try to allocate memory used by a CPU on the
1369 local memory controller of the CPU and add some more
1370 NUMA awareness to the kernel.
1372 For 64-bit this is recommended if the system is Intel Core i7
1373 (or later), AMD Opteron, or EM64T NUMA.
1375 For 32-bit this is only needed if you boot a 32-bit
1376 kernel on a 64-bit NUMA platform.
1378 Otherwise, you should say N.
1382 prompt "Old style AMD Opteron NUMA detection"
1383 depends on X86_64 && NUMA && PCI
1385 Enable AMD NUMA node topology detection. You should say Y here if
1386 you have a multi processor AMD system. This uses an old method to
1387 read the NUMA configuration directly from the builtin Northbridge
1388 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1389 which also takes priority if both are compiled in.
1391 config X86_64_ACPI_NUMA
1393 prompt "ACPI NUMA detection"
1394 depends on X86_64 && NUMA && ACPI && PCI
1397 Enable ACPI SRAT based node topology detection.
1399 # Some NUMA nodes have memory ranges that span
1400 # other nodes. Even though a pfn is valid and
1401 # between a node's start and end pfns, it may not
1402 # reside on that node. See memmap_init_zone()
1404 config NODES_SPAN_OTHER_NODES
1406 depends on X86_64_ACPI_NUMA
1409 bool "NUMA emulation"
1412 Enable NUMA emulation. A flat machine will be split
1413 into virtual nodes when booted with "numa=fake=N", where N is the
1414 number of nodes. This is only useful for debugging.
1417 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1419 default "10" if MAXSMP
1420 default "6" if X86_64
1422 depends on NEED_MULTIPLE_NODES
1424 Specify the maximum number of NUMA Nodes available on the target
1425 system. Increases memory reserved to accommodate various tables.
1427 config ARCH_HAVE_MEMORY_PRESENT
1429 depends on X86_32 && DISCONTIGMEM
1431 config NEED_NODE_MEMMAP_SIZE
1433 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1435 config ARCH_FLATMEM_ENABLE
1437 depends on X86_32 && !NUMA
1439 config ARCH_DISCONTIGMEM_ENABLE
1441 depends on NUMA && X86_32
1443 config ARCH_DISCONTIGMEM_DEFAULT
1445 depends on NUMA && X86_32
1447 config ARCH_SPARSEMEM_ENABLE
1449 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1450 select SPARSEMEM_STATIC if X86_32
1451 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1453 config ARCH_SPARSEMEM_DEFAULT
1457 config ARCH_SELECT_MEMORY_MODEL
1459 depends on ARCH_SPARSEMEM_ENABLE
1461 config ARCH_MEMORY_PROBE
1462 bool "Enable sysfs memory/probe interface"
1463 depends on X86_64 && MEMORY_HOTPLUG
1465 This option enables a sysfs memory/probe interface for testing.
1466 See Documentation/memory-hotplug.txt for more information.
1467 If you are unsure how to answer this question, answer N.
1469 config ARCH_PROC_KCORE_TEXT
1471 depends on X86_64 && PROC_KCORE
1473 config ILLEGAL_POINTER_VALUE
1476 default 0xdead000000000000 if X86_64
1480 config X86_PMEM_LEGACY_DEVICE
1483 config X86_PMEM_LEGACY
1484 tristate "Support non-standard NVDIMMs and ADR protected memory"
1485 depends on PHYS_ADDR_T_64BIT
1487 select X86_PMEM_LEGACY_DEVICE
1490 Treat memory marked using the non-standard e820 type of 12 as used
1491 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1492 The kernel will offer these regions to the 'pmem' driver so
1493 they can be used for persistent storage.
1498 bool "Allocate 3rd-level pagetables from highmem"
1501 The VM uses one page table entry for each page of physical memory.
1502 For systems with a lot of RAM, this can be wasteful of precious
1503 low memory. Setting this option will put user-space page table
1504 entries in high memory.
1506 config X86_CHECK_BIOS_CORRUPTION
1507 bool "Check for low memory corruption"
1509 Periodically check for memory corruption in low memory, which
1510 is suspected to be caused by BIOS. Even when enabled in the
1511 configuration, it is disabled at runtime. Enable it by
1512 setting "memory_corruption_check=1" on the kernel command
1513 line. By default it scans the low 64k of memory every 60
1514 seconds; see the memory_corruption_check_size and
1515 memory_corruption_check_period parameters in
1516 Documentation/kernel-parameters.txt to adjust this.
1518 When enabled with the default parameters, this option has
1519 almost no overhead, as it reserves a relatively small amount
1520 of memory and scans it infrequently. It both detects corruption
1521 and prevents it from affecting the running system.
1523 It is, however, intended as a diagnostic tool; if repeatable
1524 BIOS-originated corruption always affects the same memory,
1525 you can use memmap= to prevent the kernel from using that
1528 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1529 bool "Set the default setting of memory_corruption_check"
1530 depends on X86_CHECK_BIOS_CORRUPTION
1533 Set whether the default state of memory_corruption_check is
1536 config X86_RESERVE_LOW
1537 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1541 Specify the amount of low memory to reserve for the BIOS.
1543 The first page contains BIOS data structures that the kernel
1544 must not use, so that page must always be reserved.
1546 By default we reserve the first 64K of physical RAM, as a
1547 number of BIOSes are known to corrupt that memory range
1548 during events such as suspend/resume or monitor cable
1549 insertion, so it must not be used by the kernel.
1551 You can set this to 4 if you are absolutely sure that you
1552 trust the BIOS to get all its memory reservations and usages
1553 right. If you know your BIOS have problems beyond the
1554 default 64K area, you can set this to 640 to avoid using the
1555 entire low memory range.
1557 If you have doubts about the BIOS (e.g. suspend/resume does
1558 not work or there's kernel crashes after certain hardware
1559 hotplug events) then you might want to enable
1560 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1561 typical corruption patterns.
1563 Leave this to the default value of 64 if you are unsure.
1565 config MATH_EMULATION
1567 depends on MODIFY_LDT_SYSCALL
1568 prompt "Math emulation" if X86_32
1570 Linux can emulate a math coprocessor (used for floating point
1571 operations) if you don't have one. 486DX and Pentium processors have
1572 a math coprocessor built in, 486SX and 386 do not, unless you added
1573 a 487DX or 387, respectively. (The messages during boot time can
1574 give you some hints here ["man dmesg"].) Everyone needs either a
1575 coprocessor or this emulation.
1577 If you don't have a math coprocessor, you need to say Y here; if you
1578 say Y here even though you have a coprocessor, the coprocessor will
1579 be used nevertheless. (This behavior can be changed with the kernel
1580 command line option "no387", which comes handy if your coprocessor
1581 is broken. Try "man bootparam" or see the documentation of your boot
1582 loader (lilo or loadlin) about how to pass options to the kernel at
1583 boot time.) This means that it is a good idea to say Y here if you
1584 intend to use this kernel on different machines.
1586 More information about the internals of the Linux math coprocessor
1587 emulation can be found in <file:arch/x86/math-emu/README>.
1589 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1590 kernel, it won't hurt.
1594 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1596 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1597 the Memory Type Range Registers (MTRRs) may be used to control
1598 processor access to memory ranges. This is most useful if you have
1599 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1600 allows bus write transfers to be combined into a larger transfer
1601 before bursting over the PCI/AGP bus. This can increase performance
1602 of image write operations 2.5 times or more. Saying Y here creates a
1603 /proc/mtrr file which may be used to manipulate your processor's
1604 MTRRs. Typically the X server should use this.
1606 This code has a reasonably generic interface so that similar
1607 control registers on other processors can be easily supported
1610 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1611 Registers (ARRs) which provide a similar functionality to MTRRs. For
1612 these, the ARRs are used to emulate the MTRRs.
1613 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1614 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1615 write-combining. All of these processors are supported by this code
1616 and it makes sense to say Y here if you have one of them.
1618 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1619 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1620 can lead to all sorts of problems, so it's good to say Y here.
1622 You can safely say Y even if your machine doesn't have MTRRs, you'll
1623 just add about 9 KB to your kernel.
1625 See <file:Documentation/x86/mtrr.txt> for more information.
1627 config MTRR_SANITIZER
1629 prompt "MTRR cleanup support"
1632 Convert MTRR layout from continuous to discrete, so X drivers can
1633 add writeback entries.
1635 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1636 The largest mtrr entry size for a continuous block can be set with
1641 config MTRR_SANITIZER_ENABLE_DEFAULT
1642 int "MTRR cleanup enable value (0-1)"
1645 depends on MTRR_SANITIZER
1647 Enable mtrr cleanup default value
1649 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1650 int "MTRR cleanup spare reg num (0-7)"
1653 depends on MTRR_SANITIZER
1655 mtrr cleanup spare entries default, it can be changed via
1656 mtrr_spare_reg_nr=N on the kernel command line.
1660 prompt "x86 PAT support" if EXPERT
1663 Use PAT attributes to setup page level cache control.
1665 PATs are the modern equivalents of MTRRs and are much more
1666 flexible than MTRRs.
1668 Say N here if you see bootup problems (boot crash, boot hang,
1669 spontaneous reboots) or a non-working video driver.
1673 config ARCH_USES_PG_UNCACHED
1679 prompt "x86 architectural random number generator" if EXPERT
1681 Enable the x86 architectural RDRAND instruction
1682 (Intel Bull Mountain technology) to generate random numbers.
1683 If supported, this is a high bandwidth, cryptographically
1684 secure hardware random number generator.
1688 prompt "Supervisor Mode Access Prevention" if EXPERT
1690 Supervisor Mode Access Prevention (SMAP) is a security
1691 feature in newer Intel processors. There is a small
1692 performance cost if this enabled and turned on; there is
1693 also a small increase in the kernel size if this is enabled.
1697 config X86_INTEL_MPX
1698 prompt "Intel MPX (Memory Protection Extensions)"
1700 depends on CPU_SUP_INTEL
1702 MPX provides hardware features that can be used in
1703 conjunction with compiler-instrumented code to check
1704 memory references. It is designed to detect buffer
1705 overflow or underflow bugs.
1707 This option enables running applications which are
1708 instrumented or otherwise use MPX. It does not use MPX
1709 itself inside the kernel or to protect the kernel
1710 against bad memory references.
1712 Enabling this option will make the kernel larger:
1713 ~8k of kernel text and 36 bytes of data on a 64-bit
1714 defconfig. It adds a long to the 'mm_struct' which
1715 will increase the kernel memory overhead of each
1716 process and adds some branches to paths used during
1717 exec() and munmap().
1719 For details, see Documentation/x86/intel_mpx.txt
1723 config X86_INTEL_MEMORY_PROTECTION_KEYS
1724 prompt "Intel Memory Protection Keys"
1726 # Note: only available in 64-bit mode
1727 depends on CPU_SUP_INTEL && X86_64
1729 Memory Protection Keys provides a mechanism for enforcing
1730 page-based protections, but without requiring modification of the
1731 page tables when an application changes protection domains.
1733 For details, see Documentation/x86/protection-keys.txt
1738 bool "EFI runtime service support"
1741 select EFI_RUNTIME_WRAPPERS
1743 This enables the kernel to use EFI runtime services that are
1744 available (such as the EFI variable services).
1746 This option is only useful on systems that have EFI firmware.
1747 In addition, you should use the latest ELILO loader available
1748 at <http://elilo.sourceforge.net> in order to take advantage
1749 of EFI runtime services. However, even with this option, the
1750 resultant kernel should continue to boot on existing non-EFI
1754 bool "EFI stub support"
1755 depends on EFI && !X86_USE_3DNOW
1758 This kernel feature allows a bzImage to be loaded directly
1759 by EFI firmware without the use of a bootloader.
1761 See Documentation/efi-stub.txt for more information.
1764 bool "EFI mixed-mode support"
1765 depends on EFI_STUB && X86_64
1767 Enabling this feature allows a 64-bit kernel to be booted
1768 on a 32-bit firmware, provided that your CPU supports 64-bit
1771 Note that it is not possible to boot a mixed-mode enabled
1772 kernel via the EFI boot stub - a bootloader that supports
1773 the EFI handover protocol must be used.
1779 prompt "Enable seccomp to safely compute untrusted bytecode"
1781 This kernel feature is useful for number crunching applications
1782 that may need to compute untrusted bytecode during their
1783 execution. By using pipes or other transports made available to
1784 the process as file descriptors supporting the read/write
1785 syscalls, it's possible to isolate those applications in
1786 their own address space using seccomp. Once seccomp is
1787 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1788 and the task is only allowed to execute a few safe syscalls
1789 defined by each seccomp mode.
1791 If unsure, say Y. Only embedded should say N here.
1793 source kernel/Kconfig.hz
1796 bool "kexec system call"
1799 kexec is a system call that implements the ability to shutdown your
1800 current kernel, and to start another kernel. It is like a reboot
1801 but it is independent of the system firmware. And like a reboot
1802 you can start any kernel with it, not just Linux.
1804 The name comes from the similarity to the exec system call.
1806 It is an ongoing process to be certain the hardware in a machine
1807 is properly shutdown, so do not be surprised if this code does not
1808 initially work for you. As of this writing the exact hardware
1809 interface is strongly in flux, so no good recommendation can be
1813 bool "kexec file based system call"
1818 depends on CRYPTO_SHA256=y
1820 This is new version of kexec system call. This system call is
1821 file based and takes file descriptors as system call argument
1822 for kernel and initramfs as opposed to list of segments as
1823 accepted by previous system call.
1825 config KEXEC_VERIFY_SIG
1826 bool "Verify kernel signature during kexec_file_load() syscall"
1827 depends on KEXEC_FILE
1829 This option makes kernel signature verification mandatory for
1830 the kexec_file_load() syscall.
1832 In addition to that option, you need to enable signature
1833 verification for the corresponding kernel image type being
1834 loaded in order for this to work.
1836 config KEXEC_BZIMAGE_VERIFY_SIG
1837 bool "Enable bzImage signature verification support"
1838 depends on KEXEC_VERIFY_SIG
1839 depends on SIGNED_PE_FILE_VERIFICATION
1840 select SYSTEM_TRUSTED_KEYRING
1842 Enable bzImage signature verification support.
1845 bool "kernel crash dumps"
1846 depends on X86_64 || (X86_32 && HIGHMEM)
1848 Generate crash dump after being started by kexec.
1849 This should be normally only set in special crash dump kernels
1850 which are loaded in the main kernel with kexec-tools into
1851 a specially reserved region and then later executed after
1852 a crash by kdump/kexec. The crash dump kernel must be compiled
1853 to a memory address not used by the main kernel or BIOS using
1854 PHYSICAL_START, or it must be built as a relocatable image
1855 (CONFIG_RELOCATABLE=y).
1856 For more details see Documentation/kdump/kdump.txt
1860 depends on KEXEC && HIBERNATION
1862 Jump between original kernel and kexeced kernel and invoke
1863 code in physical address mode via KEXEC
1865 config PHYSICAL_START
1866 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1869 This gives the physical address where the kernel is loaded.
1871 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1872 bzImage will decompress itself to above physical address and
1873 run from there. Otherwise, bzImage will run from the address where
1874 it has been loaded by the boot loader and will ignore above physical
1877 In normal kdump cases one does not have to set/change this option
1878 as now bzImage can be compiled as a completely relocatable image
1879 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1880 address. This option is mainly useful for the folks who don't want
1881 to use a bzImage for capturing the crash dump and want to use a
1882 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1883 to be specifically compiled to run from a specific memory area
1884 (normally a reserved region) and this option comes handy.
1886 So if you are using bzImage for capturing the crash dump,
1887 leave the value here unchanged to 0x1000000 and set
1888 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1889 for capturing the crash dump change this value to start of
1890 the reserved region. In other words, it can be set based on
1891 the "X" value as specified in the "crashkernel=YM@XM"
1892 command line boot parameter passed to the panic-ed
1893 kernel. Please take a look at Documentation/kdump/kdump.txt
1894 for more details about crash dumps.
1896 Usage of bzImage for capturing the crash dump is recommended as
1897 one does not have to build two kernels. Same kernel can be used
1898 as production kernel and capture kernel. Above option should have
1899 gone away after relocatable bzImage support is introduced. But it
1900 is present because there are users out there who continue to use
1901 vmlinux for dump capture. This option should go away down the
1904 Don't change this unless you know what you are doing.
1907 bool "Build a relocatable kernel"
1910 This builds a kernel image that retains relocation information
1911 so it can be loaded someplace besides the default 1MB.
1912 The relocations tend to make the kernel binary about 10% larger,
1913 but are discarded at runtime.
1915 One use is for the kexec on panic case where the recovery kernel
1916 must live at a different physical address than the primary
1919 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1920 it has been loaded at and the compile time physical address
1921 (CONFIG_PHYSICAL_START) is used as the minimum location.
1923 config RANDOMIZE_BASE
1924 bool "Randomize the address of the kernel image"
1925 depends on RELOCATABLE
1928 Randomizes the physical and virtual address at which the
1929 kernel image is decompressed, as a security feature that
1930 deters exploit attempts relying on knowledge of the location
1931 of kernel internals.
1933 Entropy is generated using the RDRAND instruction if it is
1934 supported. If RDTSC is supported, it is used as well. If
1935 neither RDRAND nor RDTSC are supported, then randomness is
1936 read from the i8254 timer.
1938 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1939 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1940 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1941 minimum of 2MiB, only 10 bits of entropy is theoretically
1942 possible. At best, due to page table layouts, 64-bit can use
1943 9 bits of entropy and 32-bit uses 8 bits.
1947 config RANDOMIZE_BASE_MAX_OFFSET
1948 hex "Maximum kASLR offset allowed" if EXPERT
1949 depends on RANDOMIZE_BASE
1950 range 0x0 0x20000000 if X86_32
1951 default "0x20000000" if X86_32
1952 range 0x0 0x40000000 if X86_64
1953 default "0x40000000" if X86_64
1955 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1956 memory is used to determine the maximal offset in bytes that will
1957 be applied to the kernel when kernel Address Space Layout
1958 Randomization (kASLR) is active. This must be a multiple of
1961 On 32-bit this is limited to 512MiB by page table layouts. The
1964 On 64-bit this is limited by how the kernel fixmap page table is
1965 positioned, so this cannot be larger than 1GiB currently. Without
1966 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1967 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1968 modules area will shrink to compensate, up to the current maximum
1969 1GiB to 1GiB split. The default is 1GiB.
1971 If unsure, leave at the default value.
1973 # Relocation on x86 needs some additional build support
1974 config X86_NEED_RELOCS
1976 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1978 config PHYSICAL_ALIGN
1979 hex "Alignment value to which kernel should be aligned"
1981 range 0x2000 0x1000000 if X86_32
1982 range 0x200000 0x1000000 if X86_64
1984 This value puts the alignment restrictions on physical address
1985 where kernel is loaded and run from. Kernel is compiled for an
1986 address which meets above alignment restriction.
1988 If bootloader loads the kernel at a non-aligned address and
1989 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1990 address aligned to above value and run from there.
1992 If bootloader loads the kernel at a non-aligned address and
1993 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1994 load address and decompress itself to the address it has been
1995 compiled for and run from there. The address for which kernel is
1996 compiled already meets above alignment restrictions. Hence the
1997 end result is that kernel runs from a physical address meeting
1998 above alignment restrictions.
2000 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2001 this value must be a multiple of 0x200000.
2003 Don't change this unless you know what you are doing.
2006 bool "Support for hot-pluggable CPUs"
2009 Say Y here to allow turning CPUs off and on. CPUs can be
2010 controlled through /sys/devices/system/cpu.
2011 ( Note: power management support will enable this option
2012 automatically on SMP systems. )
2013 Say N if you want to disable CPU hotplug.
2015 config BOOTPARAM_HOTPLUG_CPU0
2016 bool "Set default setting of cpu0_hotpluggable"
2018 depends on HOTPLUG_CPU
2020 Set whether default state of cpu0_hotpluggable is on or off.
2022 Say Y here to enable CPU0 hotplug by default. If this switch
2023 is turned on, there is no need to give cpu0_hotplug kernel
2024 parameter and the CPU0 hotplug feature is enabled by default.
2026 Please note: there are two known CPU0 dependencies if you want
2027 to enable the CPU0 hotplug feature either by this switch or by
2028 cpu0_hotplug kernel parameter.
2030 First, resume from hibernate or suspend always starts from CPU0.
2031 So hibernate and suspend are prevented if CPU0 is offline.
2033 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2034 offline if any interrupt can not migrate out of CPU0. There may
2035 be other CPU0 dependencies.
2037 Please make sure the dependencies are under your control before
2038 you enable this feature.
2040 Say N if you don't want to enable CPU0 hotplug feature by default.
2041 You still can enable the CPU0 hotplug feature at boot by kernel
2042 parameter cpu0_hotplug.
2044 config DEBUG_HOTPLUG_CPU0
2046 prompt "Debug CPU0 hotplug"
2047 depends on HOTPLUG_CPU
2049 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2050 soon as possible and boots up userspace with CPU0 offlined. User
2051 can online CPU0 back after boot time.
2053 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2054 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2055 compilation or giving cpu0_hotplug kernel parameter at boot.
2061 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2062 depends on X86_32 || IA32_EMULATION
2064 Certain buggy versions of glibc will crash if they are
2065 presented with a 32-bit vDSO that is not mapped at the address
2066 indicated in its segment table.
2068 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2069 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2070 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2071 the only released version with the bug, but OpenSUSE 9
2072 contains a buggy "glibc 2.3.2".
2074 The symptom of the bug is that everything crashes on startup, saying:
2075 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2077 Saying Y here changes the default value of the vdso32 boot
2078 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2079 This works around the glibc bug but hurts performance.
2081 If unsure, say N: if you are compiling your own kernel, you
2082 are unlikely to be using a buggy version of glibc.
2085 prompt "vsyscall table for legacy applications"
2087 default LEGACY_VSYSCALL_EMULATE
2089 Legacy user code that does not know how to find the vDSO expects
2090 to be able to issue three syscalls by calling fixed addresses in
2091 kernel space. Since this location is not randomized with ASLR,
2092 it can be used to assist security vulnerability exploitation.
2094 This setting can be changed at boot time via the kernel command
2095 line parameter vsyscall=[native|emulate|none].
2097 On a system with recent enough glibc (2.14 or newer) and no
2098 static binaries, you can say None without a performance penalty
2099 to improve security.
2101 If unsure, select "Emulate".
2103 config LEGACY_VSYSCALL_NATIVE
2106 Actual executable code is located in the fixed vsyscall
2107 address mapping, implementing time() efficiently. Since
2108 this makes the mapping executable, it can be used during
2109 security vulnerability exploitation (traditionally as
2110 ROP gadgets). This configuration is not recommended.
2112 config LEGACY_VSYSCALL_EMULATE
2115 The kernel traps and emulates calls into the fixed
2116 vsyscall address mapping. This makes the mapping
2117 non-executable, but it still contains known contents,
2118 which could be used in certain rare security vulnerability
2119 exploits. This configuration is recommended when userspace
2120 still uses the vsyscall area.
2122 config LEGACY_VSYSCALL_NONE
2125 There will be no vsyscall mapping at all. This will
2126 eliminate any risk of ASLR bypass due to the vsyscall
2127 fixed address mapping. Attempts to use the vsyscalls
2128 will be reported to dmesg, so that either old or
2129 malicious userspace programs can be identified.
2134 bool "Built-in kernel command line"
2136 Allow for specifying boot arguments to the kernel at
2137 build time. On some systems (e.g. embedded ones), it is
2138 necessary or convenient to provide some or all of the
2139 kernel boot arguments with the kernel itself (that is,
2140 to not rely on the boot loader to provide them.)
2142 To compile command line arguments into the kernel,
2143 set this option to 'Y', then fill in the
2144 boot arguments in CONFIG_CMDLINE.
2146 Systems with fully functional boot loaders (i.e. non-embedded)
2147 should leave this option set to 'N'.
2150 string "Built-in kernel command string"
2151 depends on CMDLINE_BOOL
2154 Enter arguments here that should be compiled into the kernel
2155 image and used at boot time. If the boot loader provides a
2156 command line at boot time, it is appended to this string to
2157 form the full kernel command line, when the system boots.
2159 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2160 change this behavior.
2162 In most cases, the command line (whether built-in or provided
2163 by the boot loader) should specify the device for the root
2166 config CMDLINE_OVERRIDE
2167 bool "Built-in command line overrides boot loader arguments"
2168 depends on CMDLINE_BOOL
2170 Set this option to 'Y' to have the kernel ignore the boot loader
2171 command line, and use ONLY the built-in command line.
2173 This is used to work around broken boot loaders. This should
2174 be set to 'N' under normal conditions.
2176 config MODIFY_LDT_SYSCALL
2177 bool "Enable the LDT (local descriptor table)" if EXPERT
2180 Linux can allow user programs to install a per-process x86
2181 Local Descriptor Table (LDT) using the modify_ldt(2) system
2182 call. This is required to run 16-bit or segmented code such as
2183 DOSEMU or some Wine programs. It is also used by some very old
2184 threading libraries.
2186 Enabling this feature adds a small amount of overhead to
2187 context switches and increases the low-level kernel attack
2188 surface. Disabling it removes the modify_ldt(2) system call.
2190 Saying 'N' here may make sense for embedded or server kernels.
2192 source "kernel/livepatch/Kconfig"
2196 config ARCH_ENABLE_MEMORY_HOTPLUG
2198 depends on X86_64 || (X86_32 && HIGHMEM)
2200 config ARCH_ENABLE_MEMORY_HOTREMOVE
2202 depends on MEMORY_HOTPLUG
2204 config USE_PERCPU_NUMA_NODE_ID
2208 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2210 depends on X86_64 || X86_PAE
2212 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2214 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2216 menu "Power management and ACPI options"
2218 config ARCH_HIBERNATION_HEADER
2220 depends on X86_64 && HIBERNATION
2222 source "kernel/power/Kconfig"
2224 source "drivers/acpi/Kconfig"
2226 source "drivers/sfi/Kconfig"
2233 tristate "APM (Advanced Power Management) BIOS support"
2234 depends on X86_32 && PM_SLEEP
2236 APM is a BIOS specification for saving power using several different
2237 techniques. This is mostly useful for battery powered laptops with
2238 APM compliant BIOSes. If you say Y here, the system time will be
2239 reset after a RESUME operation, the /proc/apm device will provide
2240 battery status information, and user-space programs will receive
2241 notification of APM "events" (e.g. battery status change).
2243 If you select "Y" here, you can disable actual use of the APM
2244 BIOS by passing the "apm=off" option to the kernel at boot time.
2246 Note that the APM support is almost completely disabled for
2247 machines with more than one CPU.
2249 In order to use APM, you will need supporting software. For location
2250 and more information, read <file:Documentation/power/apm-acpi.txt>
2251 and the Battery Powered Linux mini-HOWTO, available from
2252 <http://www.tldp.org/docs.html#howto>.
2254 This driver does not spin down disk drives (see the hdparm(8)
2255 manpage ("man 8 hdparm") for that), and it doesn't turn off
2256 VESA-compliant "green" monitors.
2258 This driver does not support the TI 4000M TravelMate and the ACER
2259 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2260 desktop machines also don't have compliant BIOSes, and this driver
2261 may cause those machines to panic during the boot phase.
2263 Generally, if you don't have a battery in your machine, there isn't
2264 much point in using this driver and you should say N. If you get
2265 random kernel OOPSes or reboots that don't seem to be related to
2266 anything, try disabling/enabling this option (or disabling/enabling
2269 Some other things you should try when experiencing seemingly random,
2272 1) make sure that you have enough swap space and that it is
2274 2) pass the "no-hlt" option to the kernel
2275 3) switch on floating point emulation in the kernel and pass
2276 the "no387" option to the kernel
2277 4) pass the "floppy=nodma" option to the kernel
2278 5) pass the "mem=4M" option to the kernel (thereby disabling
2279 all but the first 4 MB of RAM)
2280 6) make sure that the CPU is not over clocked.
2281 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2282 8) disable the cache from your BIOS settings
2283 9) install a fan for the video card or exchange video RAM
2284 10) install a better fan for the CPU
2285 11) exchange RAM chips
2286 12) exchange the motherboard.
2288 To compile this driver as a module, choose M here: the
2289 module will be called apm.
2293 config APM_IGNORE_USER_SUSPEND
2294 bool "Ignore USER SUSPEND"
2296 This option will ignore USER SUSPEND requests. On machines with a
2297 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2298 series notebooks, it is necessary to say Y because of a BIOS bug.
2300 config APM_DO_ENABLE
2301 bool "Enable PM at boot time"
2303 Enable APM features at boot time. From page 36 of the APM BIOS
2304 specification: "When disabled, the APM BIOS does not automatically
2305 power manage devices, enter the Standby State, enter the Suspend
2306 State, or take power saving steps in response to CPU Idle calls."
2307 This driver will make CPU Idle calls when Linux is idle (unless this
2308 feature is turned off -- see "Do CPU IDLE calls", below). This
2309 should always save battery power, but more complicated APM features
2310 will be dependent on your BIOS implementation. You may need to turn
2311 this option off if your computer hangs at boot time when using APM
2312 support, or if it beeps continuously instead of suspending. Turn
2313 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2314 T400CDT. This is off by default since most machines do fine without
2319 bool "Make CPU Idle calls when idle"
2321 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2322 On some machines, this can activate improved power savings, such as
2323 a slowed CPU clock rate, when the machine is idle. These idle calls
2324 are made after the idle loop has run for some length of time (e.g.,
2325 333 mS). On some machines, this will cause a hang at boot time or
2326 whenever the CPU becomes idle. (On machines with more than one CPU,
2327 this option does nothing.)
2329 config APM_DISPLAY_BLANK
2330 bool "Enable console blanking using APM"
2332 Enable console blanking using the APM. Some laptops can use this to
2333 turn off the LCD backlight when the screen blanker of the Linux
2334 virtual console blanks the screen. Note that this is only used by
2335 the virtual console screen blanker, and won't turn off the backlight
2336 when using the X Window system. This also doesn't have anything to
2337 do with your VESA-compliant power-saving monitor. Further, this
2338 option doesn't work for all laptops -- it might not turn off your
2339 backlight at all, or it might print a lot of errors to the console,
2340 especially if you are using gpm.
2342 config APM_ALLOW_INTS
2343 bool "Allow interrupts during APM BIOS calls"
2345 Normally we disable external interrupts while we are making calls to
2346 the APM BIOS as a measure to lessen the effects of a badly behaving
2347 BIOS implementation. The BIOS should reenable interrupts if it
2348 needs to. Unfortunately, some BIOSes do not -- especially those in
2349 many of the newer IBM Thinkpads. If you experience hangs when you
2350 suspend, try setting this to Y. Otherwise, say N.
2354 source "drivers/cpufreq/Kconfig"
2356 source "drivers/cpuidle/Kconfig"
2358 source "drivers/idle/Kconfig"
2363 menu "Bus options (PCI etc.)"
2369 Find out whether you have a PCI motherboard. PCI is the name of a
2370 bus system, i.e. the way the CPU talks to the other stuff inside
2371 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2372 VESA. If you have PCI, say Y, otherwise N.
2375 prompt "PCI access mode"
2376 depends on X86_32 && PCI
2379 On PCI systems, the BIOS can be used to detect the PCI devices and
2380 determine their configuration. However, some old PCI motherboards
2381 have BIOS bugs and may crash if this is done. Also, some embedded
2382 PCI-based systems don't have any BIOS at all. Linux can also try to
2383 detect the PCI hardware directly without using the BIOS.
2385 With this option, you can specify how Linux should detect the
2386 PCI devices. If you choose "BIOS", the BIOS will be used,
2387 if you choose "Direct", the BIOS won't be used, and if you
2388 choose "MMConfig", then PCI Express MMCONFIG will be used.
2389 If you choose "Any", the kernel will try MMCONFIG, then the
2390 direct access method and falls back to the BIOS if that doesn't
2391 work. If unsure, go with the default, which is "Any".
2396 config PCI_GOMMCONFIG
2413 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2415 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2418 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2422 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2426 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2430 depends on PCI && XEN
2438 bool "Support mmconfig PCI config space access"
2439 depends on X86_64 && PCI && ACPI
2441 config PCI_CNB20LE_QUIRK
2442 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2445 Read the PCI windows out of the CNB20LE host bridge. This allows
2446 PCI hotplug to work on systems with the CNB20LE chipset which do
2449 There's no public spec for this chipset, and this functionality
2450 is known to be incomplete.
2452 You should say N unless you know you need this.
2454 source "drivers/pci/Kconfig"
2456 # x86_64 have no ISA slots, but can have ISA-style DMA.
2458 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2461 Enables ISA-style DMA support for devices requiring such controllers.
2469 Find out whether you have ISA slots on your motherboard. ISA is the
2470 name of a bus system, i.e. the way the CPU talks to the other stuff
2471 inside your box. Other bus systems are PCI, EISA, MicroChannel
2472 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2473 newer boards don't support it. If you have ISA, say Y, otherwise N.
2479 The Extended Industry Standard Architecture (EISA) bus was
2480 developed as an open alternative to the IBM MicroChannel bus.
2482 The EISA bus provided some of the features of the IBM MicroChannel
2483 bus while maintaining backward compatibility with cards made for
2484 the older ISA bus. The EISA bus saw limited use between 1988 and
2485 1995 when it was made obsolete by the PCI bus.
2487 Say Y here if you are building a kernel for an EISA-based machine.
2491 source "drivers/eisa/Kconfig"
2494 tristate "NatSemi SCx200 support"
2496 This provides basic support for National Semiconductor's
2497 (now AMD's) Geode processors. The driver probes for the
2498 PCI-IDs of several on-chip devices, so its a good dependency
2499 for other scx200_* drivers.
2501 If compiled as a module, the driver is named scx200.
2503 config SCx200HR_TIMER
2504 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2508 This driver provides a clocksource built upon the on-chip
2509 27MHz high-resolution timer. Its also a workaround for
2510 NSC Geode SC-1100's buggy TSC, which loses time when the
2511 processor goes idle (as is done by the scheduler). The
2512 other workaround is idle=poll boot option.
2515 bool "One Laptop Per Child support"
2522 Add support for detecting the unique features of the OLPC
2526 bool "OLPC XO-1 Power Management"
2527 depends on OLPC && MFD_CS5535 && PM_SLEEP
2530 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2533 bool "OLPC XO-1 Real Time Clock"
2534 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2536 Add support for the XO-1 real time clock, which can be used as a
2537 programmable wakeup source.
2540 bool "OLPC XO-1 SCI extras"
2541 depends on OLPC && OLPC_XO1_PM
2547 Add support for SCI-based features of the OLPC XO-1 laptop:
2548 - EC-driven system wakeups
2552 - AC adapter status updates
2553 - Battery status updates
2555 config OLPC_XO15_SCI
2556 bool "OLPC XO-1.5 SCI extras"
2557 depends on OLPC && ACPI
2560 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2561 - EC-driven system wakeups
2562 - AC adapter status updates
2563 - Battery status updates
2566 bool "PCEngines ALIX System Support (LED setup)"
2569 This option enables system support for the PCEngines ALIX.
2570 At present this just sets up LEDs for GPIO control on
2571 ALIX2/3/6 boards. However, other system specific setup should
2574 Note: You must still enable the drivers for GPIO and LED support
2575 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2577 Note: You have to set alix.force=1 for boards with Award BIOS.
2580 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2583 This option enables system support for the Soekris Engineering net5501.
2586 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2590 This option enables system support for the Traverse Technologies GEOS.
2593 bool "Technologic Systems TS-5500 platform support"
2595 select CHECK_SIGNATURE
2599 This option enables system support for the Technologic Systems TS-5500.
2605 depends on CPU_SUP_AMD && PCI
2607 source "drivers/pcmcia/Kconfig"
2610 tristate "RapidIO support"
2614 If enabled this option will include drivers and the core
2615 infrastructure code to support RapidIO interconnect devices.
2617 source "drivers/rapidio/Kconfig"
2620 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2622 Firmwares often provide initial graphics framebuffers so the BIOS,
2623 bootloader or kernel can show basic video-output during boot for
2624 user-guidance and debugging. Historically, x86 used the VESA BIOS
2625 Extensions and EFI-framebuffers for this, which are mostly limited
2627 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2628 framebuffers so the new generic system-framebuffer drivers can be
2629 used on x86. If the framebuffer is not compatible with the generic
2630 modes, it is adverticed as fallback platform framebuffer so legacy
2631 drivers like efifb, vesafb and uvesafb can pick it up.
2632 If this option is not selected, all system framebuffers are always
2633 marked as fallback platform framebuffers as usual.
2635 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2636 not be able to pick up generic system framebuffers if this option
2637 is selected. You are highly encouraged to enable simplefb as
2638 replacement if you select this option. simplefb can correctly deal
2639 with generic system framebuffers. But you should still keep vesafb
2640 and others enabled as fallback if a system framebuffer is
2641 incompatible with simplefb.
2648 menu "Executable file formats / Emulations"
2650 source "fs/Kconfig.binfmt"
2652 config IA32_EMULATION
2653 bool "IA32 Emulation"
2656 select COMPAT_BINFMT_ELF
2657 select ARCH_WANT_OLD_COMPAT_IPC
2659 Include code to run legacy 32-bit programs under a
2660 64-bit kernel. You should likely turn this on, unless you're
2661 100% sure that you don't have any 32-bit programs left.
2664 tristate "IA32 a.out support"
2665 depends on IA32_EMULATION
2667 Support old a.out binaries in the 32bit emulation.
2670 bool "x32 ABI for 64-bit mode"
2673 Include code to run binaries for the x32 native 32-bit ABI
2674 for 64-bit processors. An x32 process gets access to the
2675 full 64-bit register file and wide data path while leaving
2676 pointers at 32 bits for smaller memory footprint.
2678 You will need a recent binutils (2.22 or later) with
2679 elf32_x86_64 support enabled to compile a kernel with this
2684 depends on IA32_EMULATION || X86_X32
2687 config COMPAT_FOR_U64_ALIGNMENT
2690 config SYSVIPC_COMPAT
2702 config HAVE_ATOMIC_IOMAP
2706 config X86_DEV_DMA_OPS
2708 depends on X86_64 || STA2X11
2710 config X86_DMA_REMAP
2720 tristate "Volume Management Device Driver"
2723 Adds support for the Intel Volume Management Device (VMD). VMD is a
2724 secondary PCI host bridge that allows PCI Express root ports,
2725 and devices attached to them, to be removed from the default
2726 PCI domain and placed within the VMD domain. This provides
2727 more bus resources than are otherwise possible with a
2728 single domain. If you know your system provides one of these and
2729 has devices attached to it, say Y; if you are not sure, say N.
2731 source "net/Kconfig"
2733 source "drivers/Kconfig"
2735 source "drivers/firmware/Kconfig"
2739 source "arch/x86/Kconfig.debug"
2741 source "security/Kconfig"
2743 source "crypto/Kconfig"
2745 source "arch/x86/kvm/Kconfig"
2747 source "lib/Kconfig"
projects / cascardo / linux.git / blob