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_PMEM_API if X86_64
32 select ARCH_HAS_MMIO_FLUSH
33 select ARCH_HAS_SG_CHAIN
34 select ARCH_HAS_UBSAN_SANITIZE_ALL
35 select ARCH_HAVE_NMI_SAFE_CMPXCHG
36 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
37 select ARCH_MIGHT_HAVE_PC_PARPORT
38 select ARCH_MIGHT_HAVE_PC_SERIO
39 select ARCH_SUPPORTS_ATOMIC_RMW
40 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
41 select ARCH_SUPPORTS_INT128 if X86_64
42 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
43 select ARCH_USE_BUILTIN_BSWAP
44 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
45 select ARCH_USE_QUEUED_RWLOCKS
46 select ARCH_USE_QUEUED_SPINLOCKS
47 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
48 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
49 select ARCH_WANT_FRAME_POINTERS
50 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
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_MMAP_RND_BITS if MMU
88 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
89 select HAVE_ARCH_SECCOMP_FILTER
90 select HAVE_ARCH_SOFT_DIRTY if X86_64
91 select HAVE_ARCH_TRACEHOOK
92 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
93 select HAVE_BPF_JIT if X86_64
94 select HAVE_CC_STACKPROTECTOR
95 select HAVE_CMPXCHG_DOUBLE
96 select HAVE_CMPXCHG_LOCAL
97 select HAVE_CONTEXT_TRACKING if X86_64
98 select HAVE_COPY_THREAD_TLS
99 select HAVE_C_RECORDMCOUNT
100 select HAVE_DEBUG_KMEMLEAK
101 select HAVE_DEBUG_STACKOVERFLOW
102 select HAVE_DMA_API_DEBUG
103 select HAVE_DMA_CONTIGUOUS
104 select HAVE_DYNAMIC_FTRACE
105 select HAVE_DYNAMIC_FTRACE_WITH_REGS
106 select HAVE_EFFICIENT_UNALIGNED_ACCESS
107 select HAVE_FENTRY if X86_64
108 select HAVE_FTRACE_MCOUNT_RECORD
109 select HAVE_FUNCTION_GRAPH_FP_TEST
110 select HAVE_FUNCTION_GRAPH_TRACER
111 select HAVE_FUNCTION_TRACER
112 select HAVE_GENERIC_DMA_COHERENT if X86_32
113 select HAVE_HW_BREAKPOINT
115 select HAVE_IOREMAP_PROT
116 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
117 select HAVE_IRQ_TIME_ACCOUNTING
118 select HAVE_KERNEL_BZIP2
119 select HAVE_KERNEL_GZIP
120 select HAVE_KERNEL_LZ4
121 select HAVE_KERNEL_LZMA
122 select HAVE_KERNEL_LZO
123 select HAVE_KERNEL_XZ
125 select HAVE_KPROBES_ON_FTRACE
126 select HAVE_KRETPROBES
128 select HAVE_LIVEPATCH if X86_64
130 select HAVE_MEMBLOCK_NODE_MAP
131 select HAVE_MIXED_BREAKPOINTS_REGS
133 select HAVE_OPTPROBES
134 select HAVE_PCSPKR_PLATFORM
135 select HAVE_PERF_EVENTS
136 select HAVE_PERF_EVENTS_NMI
137 select HAVE_PERF_REGS
138 select HAVE_PERF_USER_STACK_DUMP
139 select HAVE_REGS_AND_STACK_ACCESS_API
140 select HAVE_SYSCALL_TRACEPOINTS
141 select HAVE_UID16 if X86_32 || IA32_EMULATION
142 select HAVE_UNSTABLE_SCHED_CLOCK
143 select HAVE_USER_RETURN_NOTIFIER
144 select IRQ_FORCED_THREADING
145 select MODULES_USE_ELF_RELA if X86_64
146 select MODULES_USE_ELF_REL if X86_32
147 select OLD_SIGACTION if X86_32
148 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
153 select SYSCTL_EXCEPTION_TRACE
154 select USER_STACKTRACE_SUPPORT
156 select X86_DEV_DMA_OPS if X86_64
157 select X86_FEATURE_NAMES if PROC_FS
159 config INSTRUCTION_DECODER
161 depends on KPROBES || PERF_EVENTS || UPROBES
163 config PERF_EVENTS_INTEL_UNCORE
165 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
169 default "elf32-i386" if X86_32
170 default "elf64-x86-64" if X86_64
172 config ARCH_DEFCONFIG
174 default "arch/x86/configs/i386_defconfig" if X86_32
175 default "arch/x86/configs/x86_64_defconfig" if X86_64
177 config LOCKDEP_SUPPORT
180 config STACKTRACE_SUPPORT
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 config X86_LEGACY_VM86
1046 bool "Legacy VM86 support"
1050 This option allows user programs to put the CPU into V8086
1051 mode, which is an 80286-era approximation of 16-bit real mode.
1053 Some very old versions of X and/or vbetool require this option
1054 for user mode setting. Similarly, DOSEMU will use it if
1055 available to accelerate real mode DOS programs. However, any
1056 recent version of DOSEMU, X, or vbetool should be fully
1057 functional even without kernel VM86 support, as they will all
1058 fall back to software emulation. Nevertheless, if you are using
1059 a 16-bit DOS program where 16-bit performance matters, vm86
1060 mode might be faster than emulation and you might want to
1063 Note that any app that works on a 64-bit kernel is unlikely to
1064 need this option, as 64-bit kernels don't, and can't, support
1065 V8086 mode. This option is also unrelated to 16-bit protected
1066 mode and is not needed to run most 16-bit programs under Wine.
1068 Enabling this option increases the complexity of the kernel
1069 and slows down exception handling a tiny bit.
1071 If unsure, say N here.
1075 default X86_LEGACY_VM86
1078 bool "Enable support for 16-bit segments" if EXPERT
1080 depends on MODIFY_LDT_SYSCALL
1082 This option is required by programs like Wine to run 16-bit
1083 protected mode legacy code on x86 processors. Disabling
1084 this option saves about 300 bytes on i386, or around 6K text
1085 plus 16K runtime memory on x86-64,
1089 depends on X86_16BIT && X86_32
1093 depends on X86_16BIT && X86_64
1095 config X86_VSYSCALL_EMULATION
1096 bool "Enable vsyscall emulation" if EXPERT
1100 This enables emulation of the legacy vsyscall page. Disabling
1101 it is roughly equivalent to booting with vsyscall=none, except
1102 that it will also disable the helpful warning if a program
1103 tries to use a vsyscall. With this option set to N, offending
1104 programs will just segfault, citing addresses of the form
1107 This option is required by many programs built before 2013, and
1108 care should be used even with newer programs if set to N.
1110 Disabling this option saves about 7K of kernel size and
1111 possibly 4K of additional runtime pagetable memory.
1114 tristate "Toshiba Laptop support"
1117 This adds a driver to safely access the System Management Mode of
1118 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1119 not work on models with a Phoenix BIOS. The System Management Mode
1120 is used to set the BIOS and power saving options on Toshiba portables.
1122 For information on utilities to make use of this driver see the
1123 Toshiba Linux utilities web site at:
1124 <http://www.buzzard.org.uk/toshiba/>.
1126 Say Y if you intend to run this kernel on a Toshiba portable.
1130 tristate "Dell i8k legacy laptop support"
1132 select SENSORS_DELL_SMM
1134 This option enables legacy /proc/i8k userspace interface in hwmon
1135 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1136 temperature and allows controlling fan speeds of Dell laptops via
1137 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1138 it reports also power and hotkey status. For fan speed control is
1139 needed userspace package i8kutils.
1141 Say Y if you intend to run this kernel on old Dell laptops or want to
1142 use userspace package i8kutils.
1145 config X86_REBOOTFIXUPS
1146 bool "Enable X86 board specific fixups for reboot"
1149 This enables chipset and/or board specific fixups to be done
1150 in order to get reboot to work correctly. This is only needed on
1151 some combinations of hardware and BIOS. The symptom, for which
1152 this config is intended, is when reboot ends with a stalled/hung
1155 Currently, the only fixup is for the Geode machines using
1156 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1158 Say Y if you want to enable the fixup. Currently, it's safe to
1159 enable this option even if you don't need it.
1163 bool "CPU microcode loading support"
1165 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1166 depends on BLK_DEV_INITRD
1170 If you say Y here, you will be able to update the microcode on
1171 certain Intel and AMD processors. The Intel support is for the
1172 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1173 Xeon etc. The AMD support is for families 0x10 and later. You will
1174 obviously need the actual microcode binary data itself which is not
1175 shipped with the Linux kernel.
1177 This option selects the general module only, you need to select
1178 at least one vendor specific module as well.
1180 To compile this driver as a module, choose M here: the module
1181 will be called microcode.
1183 config MICROCODE_INTEL
1184 bool "Intel microcode loading support"
1185 depends on MICROCODE
1189 This options enables microcode patch loading support for Intel
1192 For the current Intel microcode data package go to
1193 <https://downloadcenter.intel.com> and search for
1194 'Linux Processor Microcode Data File'.
1196 config MICROCODE_AMD
1197 bool "AMD microcode loading support"
1198 depends on MICROCODE
1201 If you select this option, microcode patch loading support for AMD
1202 processors will be enabled.
1204 config MICROCODE_OLD_INTERFACE
1206 depends on MICROCODE
1209 tristate "/dev/cpu/*/msr - Model-specific register support"
1211 This device gives privileged processes access to the x86
1212 Model-Specific Registers (MSRs). It is a character device with
1213 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1214 MSR accesses are directed to a specific CPU on multi-processor
1218 tristate "/dev/cpu/*/cpuid - CPU information support"
1220 This device gives processes access to the x86 CPUID instruction to
1221 be executed on a specific processor. It is a character device
1222 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1226 prompt "High Memory Support"
1233 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1234 However, the address space of 32-bit x86 processors is only 4
1235 Gigabytes large. That means that, if you have a large amount of
1236 physical memory, not all of it can be "permanently mapped" by the
1237 kernel. The physical memory that's not permanently mapped is called
1240 If you are compiling a kernel which will never run on a machine with
1241 more than 1 Gigabyte total physical RAM, answer "off" here (default
1242 choice and suitable for most users). This will result in a "3GB/1GB"
1243 split: 3GB are mapped so that each process sees a 3GB virtual memory
1244 space and the remaining part of the 4GB virtual memory space is used
1245 by the kernel to permanently map as much physical memory as
1248 If the machine has between 1 and 4 Gigabytes physical RAM, then
1251 If more than 4 Gigabytes is used then answer "64GB" here. This
1252 selection turns Intel PAE (Physical Address Extension) mode on.
1253 PAE implements 3-level paging on IA32 processors. PAE is fully
1254 supported by Linux, PAE mode is implemented on all recent Intel
1255 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1256 then the kernel will not boot on CPUs that don't support PAE!
1258 The actual amount of total physical memory will either be
1259 auto detected or can be forced by using a kernel command line option
1260 such as "mem=256M". (Try "man bootparam" or see the documentation of
1261 your boot loader (lilo or loadlin) about how to pass options to the
1262 kernel at boot time.)
1264 If unsure, say "off".
1269 Select this if you have a 32-bit processor and between 1 and 4
1270 gigabytes of physical RAM.
1277 Select this if you have a 32-bit processor and more than 4
1278 gigabytes of physical RAM.
1283 prompt "Memory split" if EXPERT
1287 Select the desired split between kernel and user memory.
1289 If the address range available to the kernel is less than the
1290 physical memory installed, the remaining memory will be available
1291 as "high memory". Accessing high memory is a little more costly
1292 than low memory, as it needs to be mapped into the kernel first.
1293 Note that increasing the kernel address space limits the range
1294 available to user programs, making the address space there
1295 tighter. Selecting anything other than the default 3G/1G split
1296 will also likely make your kernel incompatible with binary-only
1299 If you are not absolutely sure what you are doing, leave this
1303 bool "3G/1G user/kernel split"
1304 config VMSPLIT_3G_OPT
1306 bool "3G/1G user/kernel split (for full 1G low memory)"
1308 bool "2G/2G user/kernel split"
1309 config VMSPLIT_2G_OPT
1311 bool "2G/2G user/kernel split (for full 2G low memory)"
1313 bool "1G/3G user/kernel split"
1318 default 0xB0000000 if VMSPLIT_3G_OPT
1319 default 0x80000000 if VMSPLIT_2G
1320 default 0x78000000 if VMSPLIT_2G_OPT
1321 default 0x40000000 if VMSPLIT_1G
1327 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1330 bool "PAE (Physical Address Extension) Support"
1331 depends on X86_32 && !HIGHMEM4G
1334 PAE is required for NX support, and furthermore enables
1335 larger swapspace support for non-overcommit purposes. It
1336 has the cost of more pagetable lookup overhead, and also
1337 consumes more pagetable space per process.
1339 config ARCH_PHYS_ADDR_T_64BIT
1341 depends on X86_64 || X86_PAE
1343 config ARCH_DMA_ADDR_T_64BIT
1345 depends on X86_64 || HIGHMEM64G
1347 config X86_DIRECT_GBPAGES
1349 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1351 Certain kernel features effectively disable kernel
1352 linear 1 GB mappings (even if the CPU otherwise
1353 supports them), so don't confuse the user by printing
1354 that we have them enabled.
1356 # Common NUMA Features
1358 bool "Numa Memory Allocation and Scheduler Support"
1360 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1361 default y if X86_BIGSMP
1363 Enable NUMA (Non Uniform Memory Access) support.
1365 The kernel will try to allocate memory used by a CPU on the
1366 local memory controller of the CPU and add some more
1367 NUMA awareness to the kernel.
1369 For 64-bit this is recommended if the system is Intel Core i7
1370 (or later), AMD Opteron, or EM64T NUMA.
1372 For 32-bit this is only needed if you boot a 32-bit
1373 kernel on a 64-bit NUMA platform.
1375 Otherwise, you should say N.
1379 prompt "Old style AMD Opteron NUMA detection"
1380 depends on X86_64 && NUMA && PCI
1382 Enable AMD NUMA node topology detection. You should say Y here if
1383 you have a multi processor AMD system. This uses an old method to
1384 read the NUMA configuration directly from the builtin Northbridge
1385 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1386 which also takes priority if both are compiled in.
1388 config X86_64_ACPI_NUMA
1390 prompt "ACPI NUMA detection"
1391 depends on X86_64 && NUMA && ACPI && PCI
1394 Enable ACPI SRAT based node topology detection.
1396 # Some NUMA nodes have memory ranges that span
1397 # other nodes. Even though a pfn is valid and
1398 # between a node's start and end pfns, it may not
1399 # reside on that node. See memmap_init_zone()
1401 config NODES_SPAN_OTHER_NODES
1403 depends on X86_64_ACPI_NUMA
1406 bool "NUMA emulation"
1409 Enable NUMA emulation. A flat machine will be split
1410 into virtual nodes when booted with "numa=fake=N", where N is the
1411 number of nodes. This is only useful for debugging.
1414 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1416 default "10" if MAXSMP
1417 default "6" if X86_64
1419 depends on NEED_MULTIPLE_NODES
1421 Specify the maximum number of NUMA Nodes available on the target
1422 system. Increases memory reserved to accommodate various tables.
1424 config ARCH_HAVE_MEMORY_PRESENT
1426 depends on X86_32 && DISCONTIGMEM
1428 config NEED_NODE_MEMMAP_SIZE
1430 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1432 config ARCH_FLATMEM_ENABLE
1434 depends on X86_32 && !NUMA
1436 config ARCH_DISCONTIGMEM_ENABLE
1438 depends on NUMA && X86_32
1440 config ARCH_DISCONTIGMEM_DEFAULT
1442 depends on NUMA && X86_32
1444 config ARCH_SPARSEMEM_ENABLE
1446 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1447 select SPARSEMEM_STATIC if X86_32
1448 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1450 config ARCH_SPARSEMEM_DEFAULT
1454 config ARCH_SELECT_MEMORY_MODEL
1456 depends on ARCH_SPARSEMEM_ENABLE
1458 config ARCH_MEMORY_PROBE
1459 bool "Enable sysfs memory/probe interface"
1460 depends on X86_64 && MEMORY_HOTPLUG
1462 This option enables a sysfs memory/probe interface for testing.
1463 See Documentation/memory-hotplug.txt for more information.
1464 If you are unsure how to answer this question, answer N.
1466 config ARCH_PROC_KCORE_TEXT
1468 depends on X86_64 && PROC_KCORE
1470 config ILLEGAL_POINTER_VALUE
1473 default 0xdead000000000000 if X86_64
1477 config X86_PMEM_LEGACY_DEVICE
1480 config X86_PMEM_LEGACY
1481 tristate "Support non-standard NVDIMMs and ADR protected memory"
1482 depends on PHYS_ADDR_T_64BIT
1484 select X86_PMEM_LEGACY_DEVICE
1487 Treat memory marked using the non-standard e820 type of 12 as used
1488 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1489 The kernel will offer these regions to the 'pmem' driver so
1490 they can be used for persistent storage.
1495 bool "Allocate 3rd-level pagetables from highmem"
1498 The VM uses one page table entry for each page of physical memory.
1499 For systems with a lot of RAM, this can be wasteful of precious
1500 low memory. Setting this option will put user-space page table
1501 entries in high memory.
1503 config X86_CHECK_BIOS_CORRUPTION
1504 bool "Check for low memory corruption"
1506 Periodically check for memory corruption in low memory, which
1507 is suspected to be caused by BIOS. Even when enabled in the
1508 configuration, it is disabled at runtime. Enable it by
1509 setting "memory_corruption_check=1" on the kernel command
1510 line. By default it scans the low 64k of memory every 60
1511 seconds; see the memory_corruption_check_size and
1512 memory_corruption_check_period parameters in
1513 Documentation/kernel-parameters.txt to adjust this.
1515 When enabled with the default parameters, this option has
1516 almost no overhead, as it reserves a relatively small amount
1517 of memory and scans it infrequently. It both detects corruption
1518 and prevents it from affecting the running system.
1520 It is, however, intended as a diagnostic tool; if repeatable
1521 BIOS-originated corruption always affects the same memory,
1522 you can use memmap= to prevent the kernel from using that
1525 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1526 bool "Set the default setting of memory_corruption_check"
1527 depends on X86_CHECK_BIOS_CORRUPTION
1530 Set whether the default state of memory_corruption_check is
1533 config X86_RESERVE_LOW
1534 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1538 Specify the amount of low memory to reserve for the BIOS.
1540 The first page contains BIOS data structures that the kernel
1541 must not use, so that page must always be reserved.
1543 By default we reserve the first 64K of physical RAM, as a
1544 number of BIOSes are known to corrupt that memory range
1545 during events such as suspend/resume or monitor cable
1546 insertion, so it must not be used by the kernel.
1548 You can set this to 4 if you are absolutely sure that you
1549 trust the BIOS to get all its memory reservations and usages
1550 right. If you know your BIOS have problems beyond the
1551 default 64K area, you can set this to 640 to avoid using the
1552 entire low memory range.
1554 If you have doubts about the BIOS (e.g. suspend/resume does
1555 not work or there's kernel crashes after certain hardware
1556 hotplug events) then you might want to enable
1557 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1558 typical corruption patterns.
1560 Leave this to the default value of 64 if you are unsure.
1562 config MATH_EMULATION
1564 depends on MODIFY_LDT_SYSCALL
1565 prompt "Math emulation" if X86_32
1567 Linux can emulate a math coprocessor (used for floating point
1568 operations) if you don't have one. 486DX and Pentium processors have
1569 a math coprocessor built in, 486SX and 386 do not, unless you added
1570 a 487DX or 387, respectively. (The messages during boot time can
1571 give you some hints here ["man dmesg"].) Everyone needs either a
1572 coprocessor or this emulation.
1574 If you don't have a math coprocessor, you need to say Y here; if you
1575 say Y here even though you have a coprocessor, the coprocessor will
1576 be used nevertheless. (This behavior can be changed with the kernel
1577 command line option "no387", which comes handy if your coprocessor
1578 is broken. Try "man bootparam" or see the documentation of your boot
1579 loader (lilo or loadlin) about how to pass options to the kernel at
1580 boot time.) This means that it is a good idea to say Y here if you
1581 intend to use this kernel on different machines.
1583 More information about the internals of the Linux math coprocessor
1584 emulation can be found in <file:arch/x86/math-emu/README>.
1586 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1587 kernel, it won't hurt.
1591 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1593 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1594 the Memory Type Range Registers (MTRRs) may be used to control
1595 processor access to memory ranges. This is most useful if you have
1596 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1597 allows bus write transfers to be combined into a larger transfer
1598 before bursting over the PCI/AGP bus. This can increase performance
1599 of image write operations 2.5 times or more. Saying Y here creates a
1600 /proc/mtrr file which may be used to manipulate your processor's
1601 MTRRs. Typically the X server should use this.
1603 This code has a reasonably generic interface so that similar
1604 control registers on other processors can be easily supported
1607 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1608 Registers (ARRs) which provide a similar functionality to MTRRs. For
1609 these, the ARRs are used to emulate the MTRRs.
1610 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1611 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1612 write-combining. All of these processors are supported by this code
1613 and it makes sense to say Y here if you have one of them.
1615 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1616 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1617 can lead to all sorts of problems, so it's good to say Y here.
1619 You can safely say Y even if your machine doesn't have MTRRs, you'll
1620 just add about 9 KB to your kernel.
1622 See <file:Documentation/x86/mtrr.txt> for more information.
1624 config MTRR_SANITIZER
1626 prompt "MTRR cleanup support"
1629 Convert MTRR layout from continuous to discrete, so X drivers can
1630 add writeback entries.
1632 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1633 The largest mtrr entry size for a continuous block can be set with
1638 config MTRR_SANITIZER_ENABLE_DEFAULT
1639 int "MTRR cleanup enable value (0-1)"
1642 depends on MTRR_SANITIZER
1644 Enable mtrr cleanup default value
1646 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1647 int "MTRR cleanup spare reg num (0-7)"
1650 depends on MTRR_SANITIZER
1652 mtrr cleanup spare entries default, it can be changed via
1653 mtrr_spare_reg_nr=N on the kernel command line.
1657 prompt "x86 PAT support" if EXPERT
1660 Use PAT attributes to setup page level cache control.
1662 PATs are the modern equivalents of MTRRs and are much more
1663 flexible than MTRRs.
1665 Say N here if you see bootup problems (boot crash, boot hang,
1666 spontaneous reboots) or a non-working video driver.
1670 config ARCH_USES_PG_UNCACHED
1676 prompt "x86 architectural random number generator" if EXPERT
1678 Enable the x86 architectural RDRAND instruction
1679 (Intel Bull Mountain technology) to generate random numbers.
1680 If supported, this is a high bandwidth, cryptographically
1681 secure hardware random number generator.
1685 prompt "Supervisor Mode Access Prevention" if EXPERT
1687 Supervisor Mode Access Prevention (SMAP) is a security
1688 feature in newer Intel processors. There is a small
1689 performance cost if this enabled and turned on; there is
1690 also a small increase in the kernel size if this is enabled.
1694 config X86_INTEL_MPX
1695 prompt "Intel MPX (Memory Protection Extensions)"
1697 depends on CPU_SUP_INTEL
1699 MPX provides hardware features that can be used in
1700 conjunction with compiler-instrumented code to check
1701 memory references. It is designed to detect buffer
1702 overflow or underflow bugs.
1704 This option enables running applications which are
1705 instrumented or otherwise use MPX. It does not use MPX
1706 itself inside the kernel or to protect the kernel
1707 against bad memory references.
1709 Enabling this option will make the kernel larger:
1710 ~8k of kernel text and 36 bytes of data on a 64-bit
1711 defconfig. It adds a long to the 'mm_struct' which
1712 will increase the kernel memory overhead of each
1713 process and adds some branches to paths used during
1714 exec() and munmap().
1716 For details, see Documentation/x86/intel_mpx.txt
1721 bool "EFI runtime service support"
1724 select EFI_RUNTIME_WRAPPERS
1726 This enables the kernel to use EFI runtime services that are
1727 available (such as the EFI variable services).
1729 This option is only useful on systems that have EFI firmware.
1730 In addition, you should use the latest ELILO loader available
1731 at <http://elilo.sourceforge.net> in order to take advantage
1732 of EFI runtime services. However, even with this option, the
1733 resultant kernel should continue to boot on existing non-EFI
1737 bool "EFI stub support"
1738 depends on EFI && !X86_USE_3DNOW
1741 This kernel feature allows a bzImage to be loaded directly
1742 by EFI firmware without the use of a bootloader.
1744 See Documentation/efi-stub.txt for more information.
1747 bool "EFI mixed-mode support"
1748 depends on EFI_STUB && X86_64
1750 Enabling this feature allows a 64-bit kernel to be booted
1751 on a 32-bit firmware, provided that your CPU supports 64-bit
1754 Note that it is not possible to boot a mixed-mode enabled
1755 kernel via the EFI boot stub - a bootloader that supports
1756 the EFI handover protocol must be used.
1762 prompt "Enable seccomp to safely compute untrusted bytecode"
1764 This kernel feature is useful for number crunching applications
1765 that may need to compute untrusted bytecode during their
1766 execution. By using pipes or other transports made available to
1767 the process as file descriptors supporting the read/write
1768 syscalls, it's possible to isolate those applications in
1769 their own address space using seccomp. Once seccomp is
1770 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1771 and the task is only allowed to execute a few safe syscalls
1772 defined by each seccomp mode.
1774 If unsure, say Y. Only embedded should say N here.
1776 source kernel/Kconfig.hz
1779 bool "kexec system call"
1782 kexec is a system call that implements the ability to shutdown your
1783 current kernel, and to start another kernel. It is like a reboot
1784 but it is independent of the system firmware. And like a reboot
1785 you can start any kernel with it, not just Linux.
1787 The name comes from the similarity to the exec system call.
1789 It is an ongoing process to be certain the hardware in a machine
1790 is properly shutdown, so do not be surprised if this code does not
1791 initially work for you. As of this writing the exact hardware
1792 interface is strongly in flux, so no good recommendation can be
1796 bool "kexec file based system call"
1801 depends on CRYPTO_SHA256=y
1803 This is new version of kexec system call. This system call is
1804 file based and takes file descriptors as system call argument
1805 for kernel and initramfs as opposed to list of segments as
1806 accepted by previous system call.
1808 config KEXEC_VERIFY_SIG
1809 bool "Verify kernel signature during kexec_file_load() syscall"
1810 depends on KEXEC_FILE
1812 This option makes kernel signature verification mandatory for
1813 the kexec_file_load() syscall.
1815 In addition to that option, you need to enable signature
1816 verification for the corresponding kernel image type being
1817 loaded in order for this to work.
1819 config KEXEC_BZIMAGE_VERIFY_SIG
1820 bool "Enable bzImage signature verification support"
1821 depends on KEXEC_VERIFY_SIG
1822 depends on SIGNED_PE_FILE_VERIFICATION
1823 select SYSTEM_TRUSTED_KEYRING
1825 Enable bzImage signature verification support.
1828 bool "kernel crash dumps"
1829 depends on X86_64 || (X86_32 && HIGHMEM)
1831 Generate crash dump after being started by kexec.
1832 This should be normally only set in special crash dump kernels
1833 which are loaded in the main kernel with kexec-tools into
1834 a specially reserved region and then later executed after
1835 a crash by kdump/kexec. The crash dump kernel must be compiled
1836 to a memory address not used by the main kernel or BIOS using
1837 PHYSICAL_START, or it must be built as a relocatable image
1838 (CONFIG_RELOCATABLE=y).
1839 For more details see Documentation/kdump/kdump.txt
1843 depends on KEXEC && HIBERNATION
1845 Jump between original kernel and kexeced kernel and invoke
1846 code in physical address mode via KEXEC
1848 config PHYSICAL_START
1849 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1852 This gives the physical address where the kernel is loaded.
1854 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1855 bzImage will decompress itself to above physical address and
1856 run from there. Otherwise, bzImage will run from the address where
1857 it has been loaded by the boot loader and will ignore above physical
1860 In normal kdump cases one does not have to set/change this option
1861 as now bzImage can be compiled as a completely relocatable image
1862 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1863 address. This option is mainly useful for the folks who don't want
1864 to use a bzImage for capturing the crash dump and want to use a
1865 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1866 to be specifically compiled to run from a specific memory area
1867 (normally a reserved region) and this option comes handy.
1869 So if you are using bzImage for capturing the crash dump,
1870 leave the value here unchanged to 0x1000000 and set
1871 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1872 for capturing the crash dump change this value to start of
1873 the reserved region. In other words, it can be set based on
1874 the "X" value as specified in the "crashkernel=YM@XM"
1875 command line boot parameter passed to the panic-ed
1876 kernel. Please take a look at Documentation/kdump/kdump.txt
1877 for more details about crash dumps.
1879 Usage of bzImage for capturing the crash dump is recommended as
1880 one does not have to build two kernels. Same kernel can be used
1881 as production kernel and capture kernel. Above option should have
1882 gone away after relocatable bzImage support is introduced. But it
1883 is present because there are users out there who continue to use
1884 vmlinux for dump capture. This option should go away down the
1887 Don't change this unless you know what you are doing.
1890 bool "Build a relocatable kernel"
1893 This builds a kernel image that retains relocation information
1894 so it can be loaded someplace besides the default 1MB.
1895 The relocations tend to make the kernel binary about 10% larger,
1896 but are discarded at runtime.
1898 One use is for the kexec on panic case where the recovery kernel
1899 must live at a different physical address than the primary
1902 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1903 it has been loaded at and the compile time physical address
1904 (CONFIG_PHYSICAL_START) is used as the minimum location.
1906 config RANDOMIZE_BASE
1907 bool "Randomize the address of the kernel image"
1908 depends on RELOCATABLE
1911 Randomizes the physical and virtual address at which the
1912 kernel image is decompressed, as a security feature that
1913 deters exploit attempts relying on knowledge of the location
1914 of kernel internals.
1916 Entropy is generated using the RDRAND instruction if it is
1917 supported. If RDTSC is supported, it is used as well. If
1918 neither RDRAND nor RDTSC are supported, then randomness is
1919 read from the i8254 timer.
1921 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1922 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1923 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1924 minimum of 2MiB, only 10 bits of entropy is theoretically
1925 possible. At best, due to page table layouts, 64-bit can use
1926 9 bits of entropy and 32-bit uses 8 bits.
1930 config RANDOMIZE_BASE_MAX_OFFSET
1931 hex "Maximum kASLR offset allowed" if EXPERT
1932 depends on RANDOMIZE_BASE
1933 range 0x0 0x20000000 if X86_32
1934 default "0x20000000" if X86_32
1935 range 0x0 0x40000000 if X86_64
1936 default "0x40000000" if X86_64
1938 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1939 memory is used to determine the maximal offset in bytes that will
1940 be applied to the kernel when kernel Address Space Layout
1941 Randomization (kASLR) is active. This must be a multiple of
1944 On 32-bit this is limited to 512MiB by page table layouts. The
1947 On 64-bit this is limited by how the kernel fixmap page table is
1948 positioned, so this cannot be larger than 1GiB currently. Without
1949 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1950 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1951 modules area will shrink to compensate, up to the current maximum
1952 1GiB to 1GiB split. The default is 1GiB.
1954 If unsure, leave at the default value.
1956 # Relocation on x86 needs some additional build support
1957 config X86_NEED_RELOCS
1959 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1961 config PHYSICAL_ALIGN
1962 hex "Alignment value to which kernel should be aligned"
1964 range 0x2000 0x1000000 if X86_32
1965 range 0x200000 0x1000000 if X86_64
1967 This value puts the alignment restrictions on physical address
1968 where kernel is loaded and run from. Kernel is compiled for an
1969 address which meets above alignment restriction.
1971 If bootloader loads the kernel at a non-aligned address and
1972 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1973 address aligned to above value and run from there.
1975 If bootloader loads the kernel at a non-aligned address and
1976 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1977 load address and decompress itself to the address it has been
1978 compiled for and run from there. The address for which kernel is
1979 compiled already meets above alignment restrictions. Hence the
1980 end result is that kernel runs from a physical address meeting
1981 above alignment restrictions.
1983 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1984 this value must be a multiple of 0x200000.
1986 Don't change this unless you know what you are doing.
1989 bool "Support for hot-pluggable CPUs"
1992 Say Y here to allow turning CPUs off and on. CPUs can be
1993 controlled through /sys/devices/system/cpu.
1994 ( Note: power management support will enable this option
1995 automatically on SMP systems. )
1996 Say N if you want to disable CPU hotplug.
1998 config BOOTPARAM_HOTPLUG_CPU0
1999 bool "Set default setting of cpu0_hotpluggable"
2001 depends on HOTPLUG_CPU
2003 Set whether default state of cpu0_hotpluggable is on or off.
2005 Say Y here to enable CPU0 hotplug by default. If this switch
2006 is turned on, there is no need to give cpu0_hotplug kernel
2007 parameter and the CPU0 hotplug feature is enabled by default.
2009 Please note: there are two known CPU0 dependencies if you want
2010 to enable the CPU0 hotplug feature either by this switch or by
2011 cpu0_hotplug kernel parameter.
2013 First, resume from hibernate or suspend always starts from CPU0.
2014 So hibernate and suspend are prevented if CPU0 is offline.
2016 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2017 offline if any interrupt can not migrate out of CPU0. There may
2018 be other CPU0 dependencies.
2020 Please make sure the dependencies are under your control before
2021 you enable this feature.
2023 Say N if you don't want to enable CPU0 hotplug feature by default.
2024 You still can enable the CPU0 hotplug feature at boot by kernel
2025 parameter cpu0_hotplug.
2027 config DEBUG_HOTPLUG_CPU0
2029 prompt "Debug CPU0 hotplug"
2030 depends on HOTPLUG_CPU
2032 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2033 soon as possible and boots up userspace with CPU0 offlined. User
2034 can online CPU0 back after boot time.
2036 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2037 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2038 compilation or giving cpu0_hotplug kernel parameter at boot.
2044 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2045 depends on X86_32 || IA32_EMULATION
2047 Certain buggy versions of glibc will crash if they are
2048 presented with a 32-bit vDSO that is not mapped at the address
2049 indicated in its segment table.
2051 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2052 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2053 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2054 the only released version with the bug, but OpenSUSE 9
2055 contains a buggy "glibc 2.3.2".
2057 The symptom of the bug is that everything crashes on startup, saying:
2058 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2060 Saying Y here changes the default value of the vdso32 boot
2061 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2062 This works around the glibc bug but hurts performance.
2064 If unsure, say N: if you are compiling your own kernel, you
2065 are unlikely to be using a buggy version of glibc.
2068 prompt "vsyscall table for legacy applications"
2070 default LEGACY_VSYSCALL_EMULATE
2072 Legacy user code that does not know how to find the vDSO expects
2073 to be able to issue three syscalls by calling fixed addresses in
2074 kernel space. Since this location is not randomized with ASLR,
2075 it can be used to assist security vulnerability exploitation.
2077 This setting can be changed at boot time via the kernel command
2078 line parameter vsyscall=[native|emulate|none].
2080 On a system with recent enough glibc (2.14 or newer) and no
2081 static binaries, you can say None without a performance penalty
2082 to improve security.
2084 If unsure, select "Emulate".
2086 config LEGACY_VSYSCALL_NATIVE
2089 Actual executable code is located in the fixed vsyscall
2090 address mapping, implementing time() efficiently. Since
2091 this makes the mapping executable, it can be used during
2092 security vulnerability exploitation (traditionally as
2093 ROP gadgets). This configuration is not recommended.
2095 config LEGACY_VSYSCALL_EMULATE
2098 The kernel traps and emulates calls into the fixed
2099 vsyscall address mapping. This makes the mapping
2100 non-executable, but it still contains known contents,
2101 which could be used in certain rare security vulnerability
2102 exploits. This configuration is recommended when userspace
2103 still uses the vsyscall area.
2105 config LEGACY_VSYSCALL_NONE
2108 There will be no vsyscall mapping at all. This will
2109 eliminate any risk of ASLR bypass due to the vsyscall
2110 fixed address mapping. Attempts to use the vsyscalls
2111 will be reported to dmesg, so that either old or
2112 malicious userspace programs can be identified.
2117 bool "Built-in kernel command line"
2119 Allow for specifying boot arguments to the kernel at
2120 build time. On some systems (e.g. embedded ones), it is
2121 necessary or convenient to provide some or all of the
2122 kernel boot arguments with the kernel itself (that is,
2123 to not rely on the boot loader to provide them.)
2125 To compile command line arguments into the kernel,
2126 set this option to 'Y', then fill in the
2127 boot arguments in CONFIG_CMDLINE.
2129 Systems with fully functional boot loaders (i.e. non-embedded)
2130 should leave this option set to 'N'.
2133 string "Built-in kernel command string"
2134 depends on CMDLINE_BOOL
2137 Enter arguments here that should be compiled into the kernel
2138 image and used at boot time. If the boot loader provides a
2139 command line at boot time, it is appended to this string to
2140 form the full kernel command line, when the system boots.
2142 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2143 change this behavior.
2145 In most cases, the command line (whether built-in or provided
2146 by the boot loader) should specify the device for the root
2149 config CMDLINE_OVERRIDE
2150 bool "Built-in command line overrides boot loader arguments"
2151 depends on CMDLINE_BOOL
2153 Set this option to 'Y' to have the kernel ignore the boot loader
2154 command line, and use ONLY the built-in command line.
2156 This is used to work around broken boot loaders. This should
2157 be set to 'N' under normal conditions.
2159 config MODIFY_LDT_SYSCALL
2160 bool "Enable the LDT (local descriptor table)" if EXPERT
2163 Linux can allow user programs to install a per-process x86
2164 Local Descriptor Table (LDT) using the modify_ldt(2) system
2165 call. This is required to run 16-bit or segmented code such as
2166 DOSEMU or some Wine programs. It is also used by some very old
2167 threading libraries.
2169 Enabling this feature adds a small amount of overhead to
2170 context switches and increases the low-level kernel attack
2171 surface. Disabling it removes the modify_ldt(2) system call.
2173 Saying 'N' here may make sense for embedded or server kernels.
2175 source "kernel/livepatch/Kconfig"
2179 config ARCH_ENABLE_MEMORY_HOTPLUG
2181 depends on X86_64 || (X86_32 && HIGHMEM)
2183 config ARCH_ENABLE_MEMORY_HOTREMOVE
2185 depends on MEMORY_HOTPLUG
2187 config USE_PERCPU_NUMA_NODE_ID
2191 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2193 depends on X86_64 || X86_PAE
2195 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2197 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2199 menu "Power management and ACPI options"
2201 config ARCH_HIBERNATION_HEADER
2203 depends on X86_64 && HIBERNATION
2205 source "kernel/power/Kconfig"
2207 source "drivers/acpi/Kconfig"
2209 source "drivers/sfi/Kconfig"
2216 tristate "APM (Advanced Power Management) BIOS support"
2217 depends on X86_32 && PM_SLEEP
2219 APM is a BIOS specification for saving power using several different
2220 techniques. This is mostly useful for battery powered laptops with
2221 APM compliant BIOSes. If you say Y here, the system time will be
2222 reset after a RESUME operation, the /proc/apm device will provide
2223 battery status information, and user-space programs will receive
2224 notification of APM "events" (e.g. battery status change).
2226 If you select "Y" here, you can disable actual use of the APM
2227 BIOS by passing the "apm=off" option to the kernel at boot time.
2229 Note that the APM support is almost completely disabled for
2230 machines with more than one CPU.
2232 In order to use APM, you will need supporting software. For location
2233 and more information, read <file:Documentation/power/apm-acpi.txt>
2234 and the Battery Powered Linux mini-HOWTO, available from
2235 <http://www.tldp.org/docs.html#howto>.
2237 This driver does not spin down disk drives (see the hdparm(8)
2238 manpage ("man 8 hdparm") for that), and it doesn't turn off
2239 VESA-compliant "green" monitors.
2241 This driver does not support the TI 4000M TravelMate and the ACER
2242 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2243 desktop machines also don't have compliant BIOSes, and this driver
2244 may cause those machines to panic during the boot phase.
2246 Generally, if you don't have a battery in your machine, there isn't
2247 much point in using this driver and you should say N. If you get
2248 random kernel OOPSes or reboots that don't seem to be related to
2249 anything, try disabling/enabling this option (or disabling/enabling
2252 Some other things you should try when experiencing seemingly random,
2255 1) make sure that you have enough swap space and that it is
2257 2) pass the "no-hlt" option to the kernel
2258 3) switch on floating point emulation in the kernel and pass
2259 the "no387" option to the kernel
2260 4) pass the "floppy=nodma" option to the kernel
2261 5) pass the "mem=4M" option to the kernel (thereby disabling
2262 all but the first 4 MB of RAM)
2263 6) make sure that the CPU is not over clocked.
2264 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2265 8) disable the cache from your BIOS settings
2266 9) install a fan for the video card or exchange video RAM
2267 10) install a better fan for the CPU
2268 11) exchange RAM chips
2269 12) exchange the motherboard.
2271 To compile this driver as a module, choose M here: the
2272 module will be called apm.
2276 config APM_IGNORE_USER_SUSPEND
2277 bool "Ignore USER SUSPEND"
2279 This option will ignore USER SUSPEND requests. On machines with a
2280 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2281 series notebooks, it is necessary to say Y because of a BIOS bug.
2283 config APM_DO_ENABLE
2284 bool "Enable PM at boot time"
2286 Enable APM features at boot time. From page 36 of the APM BIOS
2287 specification: "When disabled, the APM BIOS does not automatically
2288 power manage devices, enter the Standby State, enter the Suspend
2289 State, or take power saving steps in response to CPU Idle calls."
2290 This driver will make CPU Idle calls when Linux is idle (unless this
2291 feature is turned off -- see "Do CPU IDLE calls", below). This
2292 should always save battery power, but more complicated APM features
2293 will be dependent on your BIOS implementation. You may need to turn
2294 this option off if your computer hangs at boot time when using APM
2295 support, or if it beeps continuously instead of suspending. Turn
2296 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2297 T400CDT. This is off by default since most machines do fine without
2302 bool "Make CPU Idle calls when idle"
2304 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2305 On some machines, this can activate improved power savings, such as
2306 a slowed CPU clock rate, when the machine is idle. These idle calls
2307 are made after the idle loop has run for some length of time (e.g.,
2308 333 mS). On some machines, this will cause a hang at boot time or
2309 whenever the CPU becomes idle. (On machines with more than one CPU,
2310 this option does nothing.)
2312 config APM_DISPLAY_BLANK
2313 bool "Enable console blanking using APM"
2315 Enable console blanking using the APM. Some laptops can use this to
2316 turn off the LCD backlight when the screen blanker of the Linux
2317 virtual console blanks the screen. Note that this is only used by
2318 the virtual console screen blanker, and won't turn off the backlight
2319 when using the X Window system. This also doesn't have anything to
2320 do with your VESA-compliant power-saving monitor. Further, this
2321 option doesn't work for all laptops -- it might not turn off your
2322 backlight at all, or it might print a lot of errors to the console,
2323 especially if you are using gpm.
2325 config APM_ALLOW_INTS
2326 bool "Allow interrupts during APM BIOS calls"
2328 Normally we disable external interrupts while we are making calls to
2329 the APM BIOS as a measure to lessen the effects of a badly behaving
2330 BIOS implementation. The BIOS should reenable interrupts if it
2331 needs to. Unfortunately, some BIOSes do not -- especially those in
2332 many of the newer IBM Thinkpads. If you experience hangs when you
2333 suspend, try setting this to Y. Otherwise, say N.
2337 source "drivers/cpufreq/Kconfig"
2339 source "drivers/cpuidle/Kconfig"
2341 source "drivers/idle/Kconfig"
2346 menu "Bus options (PCI etc.)"
2352 Find out whether you have a PCI motherboard. PCI is the name of a
2353 bus system, i.e. the way the CPU talks to the other stuff inside
2354 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2355 VESA. If you have PCI, say Y, otherwise N.
2358 prompt "PCI access mode"
2359 depends on X86_32 && PCI
2362 On PCI systems, the BIOS can be used to detect the PCI devices and
2363 determine their configuration. However, some old PCI motherboards
2364 have BIOS bugs and may crash if this is done. Also, some embedded
2365 PCI-based systems don't have any BIOS at all. Linux can also try to
2366 detect the PCI hardware directly without using the BIOS.
2368 With this option, you can specify how Linux should detect the
2369 PCI devices. If you choose "BIOS", the BIOS will be used,
2370 if you choose "Direct", the BIOS won't be used, and if you
2371 choose "MMConfig", then PCI Express MMCONFIG will be used.
2372 If you choose "Any", the kernel will try MMCONFIG, then the
2373 direct access method and falls back to the BIOS if that doesn't
2374 work. If unsure, go with the default, which is "Any".
2379 config PCI_GOMMCONFIG
2396 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2398 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2401 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2405 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2409 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2413 depends on PCI && XEN
2421 bool "Support mmconfig PCI config space access"
2422 depends on X86_64 && PCI && ACPI
2424 config PCI_CNB20LE_QUIRK
2425 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2428 Read the PCI windows out of the CNB20LE host bridge. This allows
2429 PCI hotplug to work on systems with the CNB20LE chipset which do
2432 There's no public spec for this chipset, and this functionality
2433 is known to be incomplete.
2435 You should say N unless you know you need this.
2437 source "drivers/pci/pcie/Kconfig"
2439 source "drivers/pci/Kconfig"
2441 # x86_64 have no ISA slots, but can have ISA-style DMA.
2443 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2446 Enables ISA-style DMA support for devices requiring such controllers.
2454 Find out whether you have ISA slots on your motherboard. ISA is the
2455 name of a bus system, i.e. the way the CPU talks to the other stuff
2456 inside your box. Other bus systems are PCI, EISA, MicroChannel
2457 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2458 newer boards don't support it. If you have ISA, say Y, otherwise N.
2464 The Extended Industry Standard Architecture (EISA) bus was
2465 developed as an open alternative to the IBM MicroChannel bus.
2467 The EISA bus provided some of the features of the IBM MicroChannel
2468 bus while maintaining backward compatibility with cards made for
2469 the older ISA bus. The EISA bus saw limited use between 1988 and
2470 1995 when it was made obsolete by the PCI bus.
2472 Say Y here if you are building a kernel for an EISA-based machine.
2476 source "drivers/eisa/Kconfig"
2479 tristate "NatSemi SCx200 support"
2481 This provides basic support for National Semiconductor's
2482 (now AMD's) Geode processors. The driver probes for the
2483 PCI-IDs of several on-chip devices, so its a good dependency
2484 for other scx200_* drivers.
2486 If compiled as a module, the driver is named scx200.
2488 config SCx200HR_TIMER
2489 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2493 This driver provides a clocksource built upon the on-chip
2494 27MHz high-resolution timer. Its also a workaround for
2495 NSC Geode SC-1100's buggy TSC, which loses time when the
2496 processor goes idle (as is done by the scheduler). The
2497 other workaround is idle=poll boot option.
2500 bool "One Laptop Per Child support"
2507 Add support for detecting the unique features of the OLPC
2511 bool "OLPC XO-1 Power Management"
2512 depends on OLPC && MFD_CS5535 && PM_SLEEP
2515 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2518 bool "OLPC XO-1 Real Time Clock"
2519 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2521 Add support for the XO-1 real time clock, which can be used as a
2522 programmable wakeup source.
2525 bool "OLPC XO-1 SCI extras"
2526 depends on OLPC && OLPC_XO1_PM
2532 Add support for SCI-based features of the OLPC XO-1 laptop:
2533 - EC-driven system wakeups
2537 - AC adapter status updates
2538 - Battery status updates
2540 config OLPC_XO15_SCI
2541 bool "OLPC XO-1.5 SCI extras"
2542 depends on OLPC && ACPI
2545 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2546 - EC-driven system wakeups
2547 - AC adapter status updates
2548 - Battery status updates
2551 bool "PCEngines ALIX System Support (LED setup)"
2554 This option enables system support for the PCEngines ALIX.
2555 At present this just sets up LEDs for GPIO control on
2556 ALIX2/3/6 boards. However, other system specific setup should
2559 Note: You must still enable the drivers for GPIO and LED support
2560 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2562 Note: You have to set alix.force=1 for boards with Award BIOS.
2565 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2568 This option enables system support for the Soekris Engineering net5501.
2571 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2575 This option enables system support for the Traverse Technologies GEOS.
2578 bool "Technologic Systems TS-5500 platform support"
2580 select CHECK_SIGNATURE
2584 This option enables system support for the Technologic Systems TS-5500.
2590 depends on CPU_SUP_AMD && PCI
2592 source "drivers/pcmcia/Kconfig"
2594 source "drivers/pci/hotplug/Kconfig"
2597 tristate "RapidIO support"
2601 If enabled this option will include drivers and the core
2602 infrastructure code to support RapidIO interconnect devices.
2604 source "drivers/rapidio/Kconfig"
2607 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2609 Firmwares often provide initial graphics framebuffers so the BIOS,
2610 bootloader or kernel can show basic video-output during boot for
2611 user-guidance and debugging. Historically, x86 used the VESA BIOS
2612 Extensions and EFI-framebuffers for this, which are mostly limited
2614 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2615 framebuffers so the new generic system-framebuffer drivers can be
2616 used on x86. If the framebuffer is not compatible with the generic
2617 modes, it is adverticed as fallback platform framebuffer so legacy
2618 drivers like efifb, vesafb and uvesafb can pick it up.
2619 If this option is not selected, all system framebuffers are always
2620 marked as fallback platform framebuffers as usual.
2622 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2623 not be able to pick up generic system framebuffers if this option
2624 is selected. You are highly encouraged to enable simplefb as
2625 replacement if you select this option. simplefb can correctly deal
2626 with generic system framebuffers. But you should still keep vesafb
2627 and others enabled as fallback if a system framebuffer is
2628 incompatible with simplefb.
2635 menu "Executable file formats / Emulations"
2637 source "fs/Kconfig.binfmt"
2639 config IA32_EMULATION
2640 bool "IA32 Emulation"
2643 select COMPAT_BINFMT_ELF
2644 select ARCH_WANT_OLD_COMPAT_IPC
2646 Include code to run legacy 32-bit programs under a
2647 64-bit kernel. You should likely turn this on, unless you're
2648 100% sure that you don't have any 32-bit programs left.
2651 tristate "IA32 a.out support"
2652 depends on IA32_EMULATION
2654 Support old a.out binaries in the 32bit emulation.
2657 bool "x32 ABI for 64-bit mode"
2660 Include code to run binaries for the x32 native 32-bit ABI
2661 for 64-bit processors. An x32 process gets access to the
2662 full 64-bit register file and wide data path while leaving
2663 pointers at 32 bits for smaller memory footprint.
2665 You will need a recent binutils (2.22 or later) with
2666 elf32_x86_64 support enabled to compile a kernel with this
2671 depends on IA32_EMULATION || X86_X32
2674 config COMPAT_FOR_U64_ALIGNMENT
2677 config SYSVIPC_COMPAT
2689 config HAVE_ATOMIC_IOMAP
2693 config X86_DEV_DMA_OPS
2695 depends on X86_64 || STA2X11
2697 config X86_DMA_REMAP
2707 tristate "Volume Management Device Driver"
2710 Adds support for the Intel Volume Management Device (VMD). VMD is a
2711 secondary PCI host bridge that allows PCI Express root ports,
2712 and devices attached to them, to be removed from the default
2713 PCI domain and placed within the VMD domain. This provides
2714 more bus resources than are otherwise possible with a
2715 single domain. If you know your system provides one of these and
2716 has devices attached to it, say Y; if you are not sure, say N.
2718 source "net/Kconfig"
2720 source "drivers/Kconfig"
2722 source "drivers/firmware/Kconfig"
2726 source "arch/x86/Kconfig.debug"
2728 source "security/Kconfig"
2730 source "crypto/Kconfig"
2732 source "arch/x86/kvm/Kconfig"
2734 source "lib/Kconfig"
projects / cascardo / linux.git / blob